Ink Jet Image Formation Apparatus With Means for Collecting Ink Mist

1. Field of the Invention

The present invention relates to an image formation apparatus and, more particularly, to an image formation apparatus which has a convey system for a recording medium in a continuous paper form such as fan fold paper, a recording means for forming images along the entire width of the recording medium, and the like.

2. Related Background Art

Conventional image formation apparatuses of the type described above are disclosed in Japanese Patent Applications No. 065103/1985-No. 065122/1985 whose assignee is the same as that of the present invention. The apparatus disclosed in either application has a recording means (with a convey system and a liquid jet recording device which can be connected and disconnected with ease), and a recovery means for recovering ejection of the liquid jet recording device. When the convey system and the recording device are disconnected, replacement of the recording medium and maintenance of the respective parts is easy. When the convey system and the recording device are connected, the respective parts are appropriately arranged, and high-quality images can be formed.

In the apparatus described above, it is strongly desired that an appropriate means can exhaust fine ink mist produced from ejected ink droplets outside the apparatus so as to prevent a recording medium and the apparatus from being contaminated therewith.

It is an object of the present invention to provide an image formation apparatus wherein a suction airflow is formed using a fan and a member which can maintain an appropriate distance to a liquid jet port of a recording means and against which a recording medium abuts, so as to trap fine ink mist produced from ejected ink droplets, and an absorbing member is caused to absorb the trapped mist and is replaced with a new one as needed so as to exhaust the ink mist outside the apparatus.

FIGS. 1, 2A, and 2B are perspective views showing an example of the schematic construction of an image formation apparatus according to the present invention;

FIG. 3 is a perspective view of an open paper feed unit showing an example of the internal construction of a recording system unit 100;

FIG. 4 is a perspective view showing the open paper feed unit for explaining its internal construction;

FIGS. 5A to 5C are views for explaining an example of the internal construction of a controller unit;

FIGS. 6A to 6E are views showing an example of the setting state of fan fold paper as a recording medium;

FIG. 7 is a plan view showing an example of the configuration of a display panel;

FIG. 8 is a diagram showing the display contents of a 7-segment display;

FIG. 9 is a perspective view showing an example of a switch and a display inside the apparatus of FIG. 1;

FIGS. 10A to 10D are diagrams showing an example of replacement procedures of a drain tank;

FIG. 11 is a view showing an example of the detailed construction of a paper feed unit;

FIGS. 12A to 12C are views showing an example of the construction of a paper deck section;

FIG. 13 is a view showing an example of the construction of a lower paper feed mechanism and a lower roller open/close mechanism;

FIG. 14A is a view showing an example of the construction of a main part of a recording surface forming section including a platen;

FIG. 14B is a sectional view showing a platen mount base and an airflow;

FIG. 14C is a detailed sectional view of a duct section;

FIG. 15 is a diagram showing an example of the construction of a motor unit;

FIG. 16 is a view showing an example of the construction of an upper feed roller and its power transmission mechanism;

FIG. 17 is a view showing an example of the construction of a part including upper pinch rollers;

FIG. 18 is a view showing an example of the construction of a paper feed unit cover;

FIGS. 19A and 19B show a flap open/close mechanism;

FIGS. 20A to 20C show a state wherein a feed-out port is closed, a state wherein a flap is pivoted to a predetermined position, and a state wherein the flap is closed to open the feed-out port;

FIG. 21 is a perspective view showing a paper feed unit from below in order to explain the mounting state of a stacker;

FIG. 22 is a longitudinal sectional view of a stacker arranged below the paper feed unit in a state wherein the stacker is used;

FIGS. 23 and 24 are views showing lock mechanisms mounted at upper and lower portions of the paper feed unit, respectively;

FIGS. 25 and 26 are views showing a handle lever and its power transmission mechanism;

FIG. 27 is a diagram showing an example of the construction of a controller unit;

FIGS. 28 and 29 are views showing a cap respectively in the open and closed states with respect to a cap cover;

FIGS. 30 and 31 are perspective views showing an example of the cap cover;

FIG. 32 is a view showing an example of the construction of a head assembly;

FIG. 33 is an exploded view of a support structure for a recording head assembly in a recording system unit;

FIG. 34 is a sectional view showing an example of the coupled state between a stationary table and a movable table;

FIG. 35 is a block diagram showing an example of the electrical configuration of the overall image formation apparatus according to the present invention;

FIGS. 36, 37 and 38 are flow charts showing an example of the operation according to the present invention;

FIG. 39 is a table showing the arrangement of switches;

FIG. 40 is a table showing test patterns;

FIG. 41 is a view showing a registration adjustment process;

FIG. 42 is a view showing structure near a monitor terminal;

FIG. 43 is a view showing an example of a head voltage adjustment mechanism.

FIG. 44 is the protocol for command data reception;

FIG. 45 is the protocol for the reception of a print start command to reception of image data; and

FIG. 46 is the protocol for detection of an error in hardware of the communication system.

The present invention will be described in more detail with reference to the accompanying drawings.

FIGS. 1, 2A and 2B show an example of the schematic construction of an image formation apparatus of the present invention. The image formation apparatus of this embodiment can be connected to a host system which supplies image information and control signals for image recording.

In FIGS. 1, 2A and 2B, the reference numerals, and the names, functions and meanings of the respective parts correspond to each other in the following Table 1.

(1) Interior of Recording System

FIG. 3 is a perspective view showing an open state of the paper feed unit 300 in order to show an example of its internal construction. The reference numerals, and the names, functions and meanings of the respective parts correspond as shown below. In this system, a control system including a recording head 110 and a cartridge tank 120 can be an ink-jet printer as disclosed in Japanese Patent Application Nos. 244131/1983 to 244138/1983, whose assignee is the same as that of this application.

(2) Interior of Paper Feed Unit

FIG. 4 is a perspective view showing the open paper feed unit 300 so as to show its internal construction. The reference numerals, and the names, functions and meanings of the respective parts correspond to each other as follows shown in the following Table 3.

(3) Interior of Controller

FIGS. 5A to 5C are views for explaining an example of the internal construction of the controller unit 200. In this embodiment, the controller unit 200 is arranged below the recording system unit 100. The controller unit 200 can be maintained and inspected separately from the recording system unit 100. In addition, when ink leaks inside the unit 100, the controller unit 200 can be shielded from the leaked ink by a shielding plate (to be described later), and the ink is guided to the drain tank 800. Thus, the controller unit 200 is protected from the adverse influence of ink leakage.

In FIGS. 5A to 5C, the reference numerals, and the names, functions and meanings of the respective parts correspond to each other as showing in the following Table 4.

The basic operation of the respective parts of the apparatus will be described below.

(1) ON/OFF of Power Source

a. ON

The power source switch 1500 is switched to its upper position while the paper feed unit 300 is closed (state shown in FIG. 1). Next, a BUSY lamp to be described later is turned on, and the respective parts are checked.

If no abnormality is detected, the BUSY lamp is turned off after about 5 to 10 seconds, and image data can be printed.

If the cap 140 is not fitted to the head unit 110, the unit 110 is automatically capped.

However, if an abnormality is detected, an error code is displayed on the display panel.

When the paper feed unit 300 is open, the head unit 110 is not automatically capped, even if it is not currently capped, since it is determined that the cap is open regardless of its position, and a cap UP/DOWN switch is depressed to close the cap.

b. OFF

The power source switch 1500 is switched to its lower position.

(2) ON LINE mode and OFF LINE mode

The ON LINE mode corresponds to the ON mode of an ON LINE lamp, and the OFF LINE mode corresponds to the off state of the ON LINE lamp.

In the ON LINE mode, the host system controls to perform form feed, initialize, and printing of image data.

In the OFF LINE mode, when an internal switch is depressed, paper feed, check print, and recovery can be performed.

Normally, the ON and OFF line modes are switched by switching the ON LINE switch. However, in one of the following modes, a switch from the OFF LINE mode to the ON LINE mode cannot be made.

BUSY lamp is ON.

Paper feed unit is open.

Head is not capped.

Error display is displayed.

The apparatus is initially in the ON LINE mode immediately after it is powered.

(3) Paper Setting

FIGS. 6A to 6C show the procedures for setting paper when fan fold paper is used as a recording medium.

It is checked if the power source is ON.

It is checked if the flap 400 is open.

The paper feed unit 300 is opened.

The deck lever lever 316A is moved up (FIG. 6A).

Paper P is set in each deck section 310 so that a black rectangular mark (TOF mark) is at the left rear side of the paper (FIG. 6B).

Move down the deck lever 316A.

The lower paper feed mechanism is opened (FIG. 6C).

The paper P is inserted between the lower feed roller 320 and the lower pinch rollers 330 (FIG. 6D).

The paper P is guided along the paper guide 380 while the upper roller 350 is opened. The paper P is kept projecting out of the flap (FIG. 6E).

The lower paper feed mechanism is closed so that the paper is not loosened.

An FF switch is depressed to feed the paper. If the paper is set in the wrong direction, the TOF mark is not detected and the feed operation is stopped.

The paper feed unit 300 is closed.

It is checked if an error is displayed on the display panel.

(4) Operation of Display Panel

FIG. 7 shows an example of the construction of the display panel 500. The correspondence between the reference numerals of the switches and the names, functions, and the effective times, and the correspondence between the reference numerals of the displays, the names, and ON times are as follows shown in the following Table 5.

FIG. 8 is a diagram for explaining the display contents of the 7-segmentdisplay 550. In this embodiment, of three digit positions, an upper digit position 552 is used as an error display section for displaying an error content, and a section 554 consisting of two lower digit positions is used as a display section for displaying the status and display corresponding to each error. Decimal points 555, 556 and 557 are respectively turned on when the apparatus is normally initialized, when a plurality of errors are present, and when the recording head assembly 130 is not mounted.

(5) Switching Operation Inside the Apparatus

FIG. 9 shows an example of switches and displays arranged inside the apparatus. The correspondence between the reference numerals of the switches and the names, functions and effective times, and correspondence between the reference numerals of the displays and the meanings in the ON times are as shown in the following Table 6.

The expendables are replenished or replaced as follows:

(1) Removal of Paper P

Removed as follows:

It is checked if the power source is ON.

The FF switch 520 is kept depressed until all the printed portion of the paper P is fed outside the flap 400.

The paper P is torn at a perforation.

The cut paper P is removed from the stacker 700.

It is checked if an error is displayed on the display panel 500.

(2) Replenishment of Ink

Ink is replenished as follows (See FIG. 3):

The paper feed unit 300 is opened.

The cap UP/DOWN switch 11 is depressed to move the cap 140, protecting the head unit 110, downward (once depressed, the cap is moved to a predetermined position even if the switch 11 is released).

The cartridge 120 is pulled.

A new cartride is inserted. Cartridges are aligned from the left in the order: black, cyan, magenta and yellow cartridges 120B, 120C, 120M and 120Y.

The cap UP/DOWN switch 11 is depressed to move the cap 140 upward (once depressed, the cap is moved to the predetermined position even if the switch 11 is released).

The paper feed unit 300 is closed.

After the cap is moved upward, ink is supplied from its corresponding color cartridge to a fixed tank by a pump (neither shown). When the fixed tank is full, the pump is stopped and printing can be started. A fixed tank as disclosed in Japanese Patent Disclosure Nos. 244131/1983 to 244138/1983 can be used.

(3) Replacement of Drain Tank 800

FIGS. 10A to 10C shown an example of the procedures for replacing the drain tank 800. The tank 800 can be replaced as follows:

a. Move up a lever 854 (FIG. 10A).

b. Draw up the drain tank 800 (FIG. 10B).

c. Remove a drain tank cap 840 (FIG. 10C).

d. Mount a new drain tank in reverse order.

e. A sealing cap 842 of the new ink tank can be mounted on the old, removed drain tank.

In the drawings, a waste ink tube is indicated by 820.

FIG. 10D is a sectional view showing an installation state of the drain tank 800. The drain tank 800 is held by the holding member 852 to have a shape that coincides with an inclination of the holding member 852. The lever 854 is coupled to the holding member 852 to be rotatable in a direction indicated by an arrow A, so that the distal end portion of the lever 854 has a dimension which coincides with the upper surface of the drain tank 800 (as indicated by an alternate long and short dashed line in FIG. 10D). In addition, a magnet member 853 assures abutment between the lever 854 and the holding member 852. In this state, if a force is applied to the drain tank 800 in a direction indicated by an arrow B by, e.g., vibration, the drain tank 800 is to be moved in a direction along the inclination of the holding member 852. However, since the lever 854 is arranged above the tank 800, and the moving direction of the tank 800 is not against the rotating direction of the lever 854 (the direction indicated by the arrow A). Therefore, the drain tank 800 will not be removed from the position shown in FIG. 10D. When the drain tank 800 is replaced, the lever 854 is rotated first, and thereafter, the drain tank 800 can be removed.

As described above, the drain tank can be reliably held, and can be easily removed by a simple mechanism.

The causes of printing errors which can be fixed include the following:

(1) Ink in the distal end of the head (nozzle) has evaporated and the ink viscosity has become very high.

(2) Air is introduced into the nozzle.

(3) Air is introduced into a liquid chamber for storing ink in the head.

These problems can be fixed by the recovery operation.

In order to allow a recovery operation, the cap 140 must be mounted on the head 100. The recovery operation is initiated by depressing the internal recovery switch 12.

The recovery processing lamp 13 is ON while the above operations are performed.

FIG. 11 shows an example of the detailed configuration of the paper feed unit 300. The paper feed unit 300 mainly has a mounting base 302. A panel 306 opposes the recording system unit 100 when the unit 100 is connected. The paper deck section 310, the lower and upper paper feed mechanisms, the open/close mechanisms 340 and 370 therefor, the platen 392 and so on are exposed through a window 306A. A surface 306B opposing the unit 100 is a gap reference surface with respect to the head unit 110 to be described later.

Portions 302A and 302B have pivot shafts for pivoting the paper feed unit 300 with respect to the recording system unit 100. A sensor 1450 detects coupling with the recording system unit 100, and a lock mechanism 1420 ensures secure coupling.

A motor 3000 drives the lower and upper feed rollers 320 and 350. A transmission mechanism 325 for the lower feed roller 320 includes a pulley G1 for transmitting rotation of the motor 3000, a bearing, a retainer, and the like. A transmission mechanism 355 for the upper feed roller 350 includes a pulley G2, a bearing, a slip plate 352 such as a retainer, and so on.

(1) Paper Deck Section 310

FIGS. 12A to 12C show an example of the paper deck section 310. A stack guide section 311 stacks the recording paper P. The stack guide section 311 has a side plate 311A as a reference surface for regulating a convey path in an initial period, a front end guide 311D for stably stacking the recording paper when the paper feed unit 100 is opened or closed, and the like. In this embodiment, the bottom plate 312 is pivotal about a pivot 312A in a direction indicated by an arrow M in FIG. 12A, and can be inclined in order to facilitate a setting operation of the recording paper. (See 2.1 (3) and FIGS. 6A to 6E for paper setting procedures.)

In FIG. 12A, a press plate 315 presses the recording paper and urges it against the side plate 311A by two springs 313 and 314, mounted between the plate 315 and the side plate 311A, so that a distance between the side plate 311A and the press plate 315 always coincides with the recording paper size. FIGS. 12B and 12C show an example of a mechanism for maintaining the press plate 315 in position.

In FIG. 12B, when the deck lever 316A is moved up, the lever member 316B is pivoted about the pivot 316D, and pushes a slide member 318 downward. The slide member 318 is received in a hole 311C of the stack guide section 311, and is pressed upward in a direction indicated by an arrow L in FIG. 12A so as to be engaged with a rack member 317 fixed to the press plate 315. FIG. 12C shows a state wherein the slide member 318 is engaged with the rack member 317 so as to maintain the press plate 315 in position.

As shown in FIG. 12B, the lever member 316B and the bottom plate 312 are coupled through a link member 316C having a rotatable pivot. Thus, when the deck lever 316A is moved up, the bottom plate 312 is also moved up in a direction indicated by an arrow N in FIG. 12B. At the same time, the slide member 318 is moved downward in the direction indicated by the arrow M in FIG. 12A. Thus, the slide member 318 is disengaged from the rack member 317, and the press plate 315 is set in a free state. At this time, when the recording paper is set, the press plate 315 is stopped at a paper width position by the springs 313 and 314. When the deck lever 316A is then pressed downward, the press plate 315 can be held in position, as described above.

In this manner, the recording paper sheets having different sheet paper widths are regulated in position at the most upstream side of the convey path and can be stably conveyed by a single paper setting operation.

(2) Lower Paper Feed Mechanism and Lower Roller Open/Close Mechanism

FIG. 13 shows an example of the construction of the lower paper feed mechanism and the lower roller open/close mechanism.

Each pinch roller 330 for pressing the recording paper P toward the lower paper feed roller 320 has an elastic member 332 along its substantially central portion in the axial direction. A nipping amount is obtained between the member 332 and the roller 320 so as to clamp the recording paper P therebetween. An open/close lever 341 is used to open or close the pinch rollers 330 with respect to the feed roller 320.

Side plates 342 support the two ends of the series of pinch rollers 330, and are pivotal about a shaft 343. A pinch roller arm 344 at each end has arm portions 344A and 344B and is supported by a pin 345 projecting from the side plate 342 between the arm portions 344A and 344B. The arm 344 is pivotal about the pin 345. The pinch rollers 330 are supported by the arm portion 344A of the arm 344, and a spring 346 is mounted between the other arm portion 344B and a bent portion 342A of the side plate 342 so as to obtain a pressing force of the pinch rollers 330 against the feed roller 320. The side plate 342 has ramp preventive rollers 338 at a position immediately before the paper P is clamped between the lower paper feed roller 320 and the pinch rollers 330. When the rollers 338 are brought into contact with the paper P, the weight of the recording paper P up to the paper deck section 310 is supported, and the winding angle of the paper P around the roller 320 can be increased. When the open/close lever 341 is operated to pivot the side plate 342 around the shaft 343, the pinch rollers 330 and the rollers 338 can be separated from the feed roller 320.

The open/close lever 341 is pivotal about a pin 342A projecting from the pinch roller side plate 342. A button 341A, which is depressed to separate the pinch rollers 330 from the feed roller 320, is arranged at one end of the lever 341. A pawl portion 341B engageable with a lock pin on the base 320 is arranged at the other end of the lever 341. A spring 349 is mounted between a button 341A of the lever 341 and the side plate 342. The spring 349 applies a counterclockwise biasing force so as to provide stable engagement.

The side of the side plate 342 facing the recording system unit 100 is a cam surface 342B which engages with the cap 140. When the cam surface 342B and the cap 140 engage with each other, the side plate 342 pivots clockwise and the feed roller 320 and the pinch rollers 330 engage. With this arrangement, even when the operator forgets to close the lower paper feed mechanism after setting the recording paper P, the lower paper feed mechanism is automatically closed upon movement of the cap 140 (to be described later). Therefore, jams of the recording paper P or the like at this portion can be prevented.

(3) Recording Surface Formation Section

FIG. 14A shows an example of the construction of the main part of the recording surface formation section 390 including the platen 392. Holes 393 are formed in the platen 392. The recording paper P is drawn by suction onto the platen surface by the fans 390F through these holes 393, thereby forming a recording surface. Springs 395 serve to pivot the platen with respect to the base 302 and the panel 306. Spring mount portions 394 are formed on the platen 392, and guide holes 396 receive pins 309 projecting from the base 302. Sensors 397 detect the recording paper P.

A seal member 398 consists of an elastic member and provides a seal between the recording surface formation section 390 and the base 302. An ink-mist trap section 399 is constituted by a duct 399A mounted on the platen 392, a porous trap member 399B for trapping ink mist, and an absorbing member 399C for absorbing the trapped ink.

FIG. 14B is a sectional view near the recording surface formation section 390 in a print mode, and shows an airflow therein. Fine ink mist produced from ejected ink droplets is moved along a neighboring airflow, and becomes attached to a wall surface against which the airflow collides.

An airflow of the fans 390F for paper suction is flowed through the ink mist trap section 399, so as to trap the ink mist. FIG. 14C shows the airflow in detail. Ink mist enters the ink mist trap section 399 through the holes of the platen 392 together with the airflow, and first collides against the trap member 399B to be trapped thereby. Furthermore, the ink mist collides against the wall surface of the duct 399A, so that the entering ink mist can be perfectly trapped. When the trapped ink mist is trapped and converted to ink droplets, the ink droplets fall in the direction indicated by an arrow A in FIG. 14A due to gravity, and are absorbed by the absorbing member 399C. An operator can replace the absorbing member 399C to exhaust the ink mist outside the apparatus.

In this manner, fine ink mist produced from ejected ink droplets is exhausted outside the apparatus by a simple method, and the interior of the apparatus can be prevented from being contaminated therewith. When the above-mentioned airflow is formed, an additional fan can be used in addition to the fans 390F.

As will be described later, when the recording system unit 100 and the paper feed unit 300 are connected, a pin formed on the front surface of the recording head unit 110 abuts against the panel 306 with a reference surface. Next, the head assembly 130 pivots to keep the nozzle of the head unit 110 and the reference surface parallel to each other. At the same time, the platen 392 follows the pivotal movement of the assembly 130 through a projection formed on the assembly 130 side. Therefore, the nozzle and the recording surface of the recording paper P, regulated by the platen 392, face each other with a predetermined gap therebetween.

(4) Motor Unit

FIG. 15 shows an example of the construction of the motor unit 3000. Rotation of a rotating shaft 3004 of a motor 3002 is transmitted to a pulley G20, associated with the lower feed transmission mechanism 325, through a pulley 3006 and a belt 3008. A pulley G3 is concentric with the pulley G20 and has a smaller diameter than the pulley G20. Rotation of the pulley G3 is transmitted to the pulley G2 of the upper feed roller transmission mechanism 355 through a belt 3010.

The gear tooth ratios of the respective pulleys are selected so that the rotational speed of the upper feed roller 350 is 2 to 3% higher than that of the lower feed roller 320.

(5) Upper Feed Roller and Its Transmission Mechanism

FIG. 16 shows an example of the construction of the upper feed roller 350, and its transmission mechanism 355. A bearing 353 is mounted on an extended shaft 351 of the roller 350 and rotatably holds the pulley G2. Slip plates 352A and 352B are mounted on the pulley G2 and the shaft 351, respectively, so as to allow sliding movement of a ring 354 and the pulley G2, which are fixed on the shaft 351. Next, rotational movement of the motor rotating shaft 3004 is transmitted to the roller 350 through the slip plates 352A and 352B, and the recording paper P is pulled upward by the upper feed roller 530 at a predetermined tension.

(6) Upper Pinch Roller and Paper Guide

FIG. 17 shows an example of the construction of a portion including the upper pinch rollers 360. Members 362.sub.1 and 362.sub.2 have portions 362.sub.1A and 362.sub.2A for regulating the displacement of the recording paper P along its widthwise direction during its setting and convey start periods, and portions 362.sub.1B and 362.sub.2B for holding the two outermost pinch rollers 360, and the like. One of these two types of members is biased to normally press the pinch rollers 360 against the feed roller 350 by a spring 372 (FIG. 11) of the upper roller open/close mechanism 370, and opens the upper paper feed mechanism upon operation of an open/close lever 374. Movement of one of these members is transmitted to the other one of these members through a coupling lever 364. In this state, the operator can set the recording paper P.

When the recording paper P is set, the leading end of the paper is guided and located at a proper location on the convey path by the guide 380 and portions 362.sub.1A and 363.sub.2A.

(7) Paper Feed Unit Cover

FIG. 18 shows an example of the construction of a portion including a paper feed unit cover 308. The portion has a feed-out port (mount port of the flap 400) 308A for the printed paper P, a mount port 308B for the display panel 500, and a mount port 308C for the hangle lever 1400.

A flap lever 410 pivots the flap 400 about a shaft 412 so as to open the port 308A. An open/close control mechanism 420 controls the open/close operation of the port 308A.

A mounting member 510 is used to mount the display panel 500 in the mount port 308B.

Groove portions 308D have mount ports for the stacker 700. Stacker hinges 710 are inserted in the groove portion 308D, so as to serve as a pivot for the stacker 700. A clamp member 790 is mounted on the front surface of the cover 308 so as to position the stacker 700, and holds the stacker 700 both in the print mode and storage mode (to be described later).

(8) Flap Open/Close Operation

FIGS. 19A and 19B show an example of the construction of the flap open/close control mechanism 420. A flap stay 422 is pivotal about a shaft 402 on the flap 400 and has a bent portion 422A and a cam hole 422B. A rotor 424 is rotatable about a shaft 432 mounted on a base 430 fixed on the cover 308. The rotor 424 has a lug 424A engageable with the bent portion 422A, as well as a pin 424B engageable with the cam surface of the cam hole 422B.

FIGS. 20A, 20B and 20C respectively show a state wherein the port 308A is closed, a state wherein the flap 400 is pivoted to a predetermined position, and a state wherein the flap 400 is locked and the port 308A is opened.

When the flap 400 is pivoted clockwise from the state shown in FIG. 20A to the state shown in FIG. 20B, the cam hole 422B and the pin 424B engage with each other, and the rotor 424 rotates counterclockwise about the shaft 432 and reaches the state shown in FIG. 19A (note that the rotation direction in FIG. 19 is opposite to that shown in FIG. 20). When the flap 400 is pivoted in the closing direction to the state shown in FIG. 20C, the lug 424A of the rotor 424 and the bent portion 422A of the flap stay 422 engage with each other, whereupon further pivoting (counterclockwise) of the flap 400 is prevented. Thus, the flap 400 is locked, the port 308A is opened, and the printed paper P can be fed. During this feeding operation, even if the operator accidentally presses the flap 400 or vibration of the flap 400 occurs, the flap 400 is locked and the port 308A will not be closed.

When the port 308A is closed, the procedures described above are followed in the reverse order. Thus, the flap 400 is pivoted clockwise from the state shown in FIG. 20C, located in the position shown in FIG. 20B, released from the locked state, and is closed as shown in FIG. 20A.

(9) Stacker Open/Close Operation

FIGS. 21A to 21C are perspective views viewed from the front side of the paper feed unit 300 in order to explain the open/close operation of the stacker 700. The stacker 700 is constituted by the following five components; the stacker hinges 710 which are rotatably engaged with the cover 308, a stacker base 720 which is a paper stack section rotatably engaged with the stacker hinges 710, stacker arms 730A and 730B which are rotatably engaged with the stacker base 720 and holds the stacker 700, and an elastic member 740 which is mounted on the stacker arm 730A. In addition, the clamp member 790 positions and holds the stacker 700.

FIG. 21A shows the inoperative mode of the stacker 700. In this case, the stacker arms 730A and 730B are folded with respect to the stacker base 720. The elastic member 740 abuts against the front surface of the cover 308. The stacker base 720 is fixed by the clamp member 790. This state is a storage state. In this state, the stacker base 720 guides the lower end of the flap 400, thereby suppressing vibration of the flap 400.

FIG. 21B shows the open/close operation of the stacker 700. First, the clamp member 790 is opened to set the stacker base 720 to be movable. Then, the stacker arms 730A and 730B are opened and are respectively fixed by the clamp member 790, thereby attaining an operative state shown in FIG. 21C.

As described above, the stacker 700 can be folded and stored on the front surface of the paper feed unit 300 in the inoperative mode. Therefore, the total volume of the apparatus can be reduced.

(10) Position of Stacker

FIG. 22 is a side view when the stacker 700 mounted on the front surface of the paper feed unit 300 is in use (projects forward).

As shown in FIG. 22, the mounting position of the stacker 700 is below the downstream side of the flap 400 by a distance corresponding to the sum of a paper stack height (distance a) and a paper feed direction width (distance b). This is because if the paper feed length is prolonged, a static force is generated due to friction between the wall surface of the cover 308 and the recording paper, and the recording paper easily jams. Therefore, a member for removing the static force is necessary. In view of this, the paper feed length is preferably as short as possible.

Since the stacker 700 is located above the paper window 600, the remaining volume of paper can be visually checked.

As described above, the stacker 700 is mounted at a position as near as possible to the flap 400, i.e., a position separated by the sum of the paper stack height and the paper feed direction width, thereby realizing a stable paper delivery state.

(1) Lock Mechanism

FIGS. 23 and 24 show lock mechanisms 1420 and 1430 arranged at the upper and lower portions of the paper feed unit 300. Lock levers 1422 and 1432 have pawls 1422A and 1432A which are pivotal about shafts 1421 and 1431 and engage with lock members arranged at the side of the recording system unit 100.

Springs 1423 and 1433 pivot the lock levers 1422 and 1432 in the locking direction. Pins 1424 and 1434 are respectively arranged between the shaft 1421 and the pawl 1422A and between the shaft 1431 and the pawl 1432A. The pins 1424 and 1434 are connected to the handle lever 1400 through wires 1425 and 1435, respectively. When the wires 1425 and 1435 are pulled downward and upward, respectively, upon operation of the handle lever 1400, the lock levers 1422 and 1432 are pivoted to release the locked state between the paper feed unit 300 and the recording system unit 100.

(2) Handle Lever

FIGS. 25 and 26 respectively show an example of the construction of the handle lever 1400 and its transmission section. An operation handle 1401 has a pin 1402 which can be connected to a transmission shaft 1412. A member 1403 has a mounting portion 1403A on the handle lever mounting hole 308C, and a flange portion 1403B. A sealing member 1404 is arranged on the flange portion 1403B. A spring 1405 applies a biasing force toward the hole 308C to the member 1403, so as to bring the sealing member 1404 in tight contact with the peripheral edge of the hole 308C. A stop ring 1406 prevents accidental removal of the pin 1402. In other words, when the handle lever 1400 is mounted, the sealing member 1404 provides a suitable seal against dust around the mounting hole 308C.

A transmission shaft 1412 is supported by a bearing 1414 and can pivot in response to operation of the handle lever 1400. A wire connecting member 1415 is fixed to the transmission shaft 1412, and has pins 1416 and 1417 which are connected to wires 1425 and 1435, respectively.

FIG. 27 shows an example of the construction of the controller unit 200. In this embodiment, the periphery of an opening 262 (for air flow or wire path) in a top plate 260 of the controller unit is bent to constitute a guide portion 264. Thus, even if ink leaks from the recording system unit 100, it will not flow into the controller unit 200. The leaked and collected ink is drained from the guide portion 264 through a hole 266 connected to a tube 826. The tube 826 is exposed outside the unit 200 through a side plate 270, and is connected to the waste ink tube 820. Ink flowing onto the top plate 260 can thereby be drained into the drain tank 800. In this manner, the interior of the controller unit 200 is protected from ink leakage from the recording system unit 100.

In this embodiment, the tube 826 is connected to the tube 820. However, if ink collected by the cap 140 is guided onto the top plate 260 and into the drain tank 800 through a tube connected to the hole 266, the tube construction can be simplified.

(1) Cap Open/Close Mechanism

FIGS. 28 and 29 respectively show the closed and open states of the cap 140, with respect to the cap cover 150. Rails 141A and 141B guide the vertical movement of the cap 140. A hold member 142A holds the cap 140 such that it is pivotal about a vertical axis along the rail 141A. A member 143B engages or disengages with a slide member on the rail 141B. A waste ink reservoir 825 is arranged below the cap 140 and the tube 820 is connected to the reservoir 825.

With the arrangement described above, during a maintenance operation of the cap 140 or the like, a sufficient working area can be provided and the maintenance operation is facilitated. In addition, according to this embodiment, since the cap 140 is pivotal about a vertical axis, contamination of the head nozzle by mixing of the different colored inks at the cap can be prevented.

Referring to FIGS. 28 and 29, a cap rear surface 145 is engageable with the cam surface 342B of the pinch roller side plate 342 previously described. When the units 100 and 300 are connected with the pinch rollers 330 separated from the roller 320, the lower paper feed mechanism is closed upon downward movement of the cap 140.

(2) Cap Cover

FIG. 30 is a perspective view showing an example of the construction of the cap cover 150, and FIG. 31 is a view showing the coupling relationship between the cap cover 150 and the cap 140. Springs 151 normally apply a biasing force to the cap cover 150 toward the cap 140. Rollers 152 are engageable with a portion 149 on the front surface of the cap 140.

Rollers 152 and the portion 149 are disengaged from each other when the cap 140 faces the cap cover 150. The cover 150 is moved toward the cap 140 by the biasing force of the springs 151, and the cap 140 is covered with the cap cover 150. Thus, the cap 140 is protected from dust or becoming dried out.

When the cap 140 is moved, the rollers 152 ride on the portion 149, and the cover 150 is withdrawn against the biasing force of the springs 151. Therefore, the cover 150 does not prevent movement of the cap 140.

(3) Capping of Head Unit

Capping processing of the head unit 110 can be performed following the procedures to be described later with reference to FIG. 38. In order to obtain a proper and stable engagement at the cap position, in this embodiment, recesses 146 are formed in the front surface of the cap, as shown in FIG. 31, and projections 136 which fit in the recesses 146 are formed in the head unit 110, as shown in FIG. 32. Since the head assembly 130 is biased toward the cap, as will be described later, when the cap 140 faces the head unit 110, the projections 136 fit into the recesses 146 and movement of the cap 140 in this position is prevented. Therefore, the cap 140 can be reliably and accurately positioned with respect to the head unit 110, and a proper recovery treatment can be performed.

FIG. 32 shows an example of the construction of the recording head assembly 130. As shown in FIG. 32, the assembly 130 has projections 132 engageable with the reference surface 306B, projections 134 engageable with the front surface of the platen 392, and projections 136 which fit into recesses 146 in the cap 140. A fan 138 backs up vacuum suction of the recording paper P to the platen 392 by the fans 390F.

The head assembly 130 is mounted on a movable base shown in FIG. 33.

FIG. 33 shows an exploded state of the support structure of the recording head assembly 130 inside the recording system unit 100. A movable base 170 is movable with respect to a stationary base 160. The recording head assembly 130 is fixed on the movable base 170.

A drive mechanism 180 including a motor (pulse motor) for driving the movable base 170 is fixed to the lower surface of the stationary base 160. A screw is fixed to the distal end of the motor shaft through a universal joint. A guide mechanism 181 for converting motor rotation to linear movement is coupled to the screw. The guide mechanism 181 projects upward from an opening 161 formed at substantially the center of the stationary base 160. A part of the projecting guide mechanism 181 is mounted on a lower portion of the movable base 170. Therefore, the movable base 170 is moved by the drive mechanism 180 through the guide mechanism 181.

The drive mechanism 180 is positioned with respect to the stationary base 160 such that the movable base 170 moves in a direction perpendicular to the recording surface (in the set mode) in the paper feed unit 300. The guide mechanism 181 is mounted on the movable base 170.

Guide rails 162 and 163 are fixed on the front and back of the opening 161 in the upper surface of the stationary base 160. The direction of these rails 162 and 163 coincides with the moving direction of the movable base 170. Guide rollers 171 and 172 having vertical shafts are mounted on the front and back of the lower surface of the movable base 170. The front guide roller 171 is located inside the front guide rail 162, and the rear guide roller 172 is located inside the rear guide rail 163, so that movement of the movable base 170 is regulated by these guide rails and guide rollers and the movable base 170 is moved on a predetermined path.

A first receiving roller 164 is arranged below the stationary base 160, and its upper portion projects upward through an opening 165. The axis of the roller 164 coincides with the moving direction of the movable base 170. A second receiving roller 173 is fixed to the lower surface of the movable base 170 so that it faces the first receiving roller 164 during the forward movement of the movable base 170 (forward movement up to a recording start position). The axis of the roller 173 is perpendicular to the axis of the first receiving roller 164. The front width of the front guide rail 162 is substantially equal to the diameter of the front roller 171. The rear width of the rear guide rail 163 is substantially equal to the diameter of the rear roller 172, and its front width is larger than the diameter of the rear roller 172. In the forward movement of the movable base 170, the front guide roller 171 is located at the front portion of the front guide rail 162, and the rear roller 172 is located at the front portion of the rear guide rail 163. Therefore, the movable base 170 can oscillate in a horizontal plane about the front roller 171. Since in this case the second receiving roller 173 on the movable base side is located on the first receiving roller 164 on the stationary base side, the oscillating movement of the base 170 is further facilitated. Upon this oscillating movement of the base 170, positioning of the assembly 130 with respect to the side reference surface of the paper feed unit by the positioning front surface portion of the recording head assembly 130 fixed to the movable base 170 can be performed easily and smoothly.

As shown in FIG. 34, a lock mechanism 183 for fixing the movable base 170 with respect to the stationary base 160 during reverse movement of the base 170 is fixed to the lower surface of the base 160. The lock mechanism 183 has a solenoid 184, and a lock lever 185 driven by the solenoid 184 and pivotal within a vertical plane. The lock lever 185 has a groove 185A at the pivoting distal end. The lock lever 185 projects to the upper side of the base 160 through the opening 166 formed in the base 160. An engaging pin 174 is fixed to the lower surface of the movable base 170. The engaging pin 174 is positioned such that it is located immediately above the pivoting distal end of the lock lever 185 during reverse movement of the movable base 170. Thus, during the reverse movement of the movable base 170, the solenoid 184 is actuated and the engaging pin 174 on the side of the movable base 170 is engaged with the groove 185A at the pivoting distal end of the lock lever 185. With this arrangement, the movable base 170 (and hence the recording head assembly 130) is reliably and securely supported by the stationary base 160 (e.g., the recording head assembly 130 is reliably fixed to the recording head unit 110 during transportation of the apparatus).

When the recording head unit 110 and the paper feed unit 300 are connected during the forward movement of the movable base 170, the oscillating movement of the base 170 serves to reliably abut the positioning projections 132 on the front surface of the recording head assembly 130 against the reference surface 306B of the paper feed unit 300. In this state, the platen 392 is spring-pressed against the projections 134 similarly arranged on the front surface of the head assembly 130. Thus, the recording surface of the recording paper P regulated by the platen 392 is reliably positioned with respect to the nozzle of the assembly 130.

FIG. 35 is a block diagram showing the electrical configuration of the overall apparatus according to the present invention. Referring to FIG. 35, a host computer HC supplies image data to be printed through an optical fiber.

A modulator/demodulator MD performs conversion between photosignals and electrical signals.

A communication controller CC extracts only image data from data signals supplied from the host computer HC and supplies the image data to image memories IMM and IMS.

A main processor MP controls the overall apparatus and includes a CPU.

A mechanical controller MC includes a CPU. The mechanical controller MC performs communication with a head assembly mechanism to be described later, and also performs control operation of a pulse motor M1 for feeding fan fold paper, a DC motor M2 for vertically moving the cap, and a pulse motor M3 for horizontally (front-to-back) moving the head assembly.

The recording head unit has four recording heads (Y, M, C and B) which form an image on recording paper (fan fold paper) in accordance with image data supplied from the image memories IMM and IMS. Ink supply and recovery for each head is performed under the control of a head assembly mechanism AM.

In this embodiment, the respective blocks described above are assembled on separate printed circuits boards. The image memories (master and slave memories) IMM and IMS have a total memory capacity of 1 megabyte.

The operation of the apparatus when returned ON will be described briefly with reference to FIG. 36.

When power is supplied to the apparatus (step S1), the respective units having CPUs (MP, MC, and AM in FIG. 35) respectively perform various hardware checks including memory and port checks (step S2).

The main control of the apparatus is shifted to the main processor MP, and various system error checks including the following items are performed (step S3):

(1) Supply of recording paper

(2) Supply of ink

(3) Open/closed state of the door

(4) Mounting state of the recording head unit 110

When a "no error" state is confirmed (step S4), the ON LINE mode is set and communication with the host computer HC can be started (step S5).

When the amount of image data sent from the host computer HC and stored in the image memories IMM and IMS reaches a predetermined amount, the cap is moved down and the head assembly is moved forward to the printing position to perform printing (image formation) (step S6). During printing, further image data is received from the host computer HC (i.e., the image write and read is performed non-synchronously). This printing operation is continued unless an error occurs (step S7).

When a specific switch is depressed in the ON LINE mode in step S5, the apparatus is disconnected from the host computer HC and the OFF LINE mode is set (step S8).

Test printing, to be described in detail below, is then performed (step S9). The test pattern to be used in test printing is stored in a ROM (not shown). When a predetermined amount of the test pattern is printed, test printing is automatically stopped. In order to reset the apparatus in the ON LINE mode, the switch is depressed again (step S8 to S5).

When an error is detected in step S7, the apparatus is set in the OFF LINE mode (step S10). Such errors include paper jam, short supply of recording paper, and short supply of ink. When the cause of the error is removed (step S11), a specific reset switch is depressed to reset the apparatus in the ON LINE mode (step S12).

FIG. 37 is a flow chart for explaining the mode of operation of the apparatus when normal printing is performed.

When power is turned on (step S20), the recording head assembly is withdrawn to the home position (step S21) and the cap is moved downward (step S22). Thereafter, the recording head assembly is moved forward by the pulse motor, and stopped at the printing position corresponding to a preset number of pulses (step S23).

Head control for printing is then performed (step S24).

FIG. 38 is a flow chart showing the control sequence for covering the cap on the front surface of the recording head assembly.

The recording head assembly is withdrawn to the home position. When the assembly reaches the home position, a predetermined output is obtained from the home position sensor (step S30).

A voltage of +24 V is applied to the DC motor for cap drive to move the cap upward (step S31).

When the cap is moved upward and a sensor output indicates that the cap has reaches a predetermined position, the application voltage on the DC motor is changed to +5 V (step S32). Then, the cap is balanced with the DC motor torque and stopped.

Thereafter, a predetermined number of pulses are supplied to the recording head assembly drive pulse motor so as to move the assembly to the cap position (step S33).

Since the distal end of the recording head assembly is projected into the cap, the DC motor for driving the cap is disconnected from the power source (step S34). Thus, the cap is moved down by its own weight and engages with the recording head assembly. In this way, the capping operation is completed.

Communication between the host computer or host system and the image formation apparatus according to the present invention will be described below.

(1) Command Data

Command data exchanged between the host system and the image formation apparatus includes:

Type 1 (No operand)

Type 2 (With operand)

Command data types sent from the host system to the image formation apparatus are shown in the following Table 7.

Command data types sent from the image formation apparatus to the host system include are shown in the following Table 8.

(2) Image Data

The format of the image data is as follows:

The meanings of symbols are described in the following Table 9.

(1) Status

Before sending the command data and image data, the host system must send a status request command so as to check the status of the image formation apparatus. The host system need not send a status request command before sending specific command data (`M`, `N`, `W`) such as a status request.

The status word consists of 16 bits and has the meanings described in the following Table 10. ##STR1##

Which bit of the status is to be checked is different in each command. The following Table 11 shows the states of the respective bits of the status words when execution of commands and image data input are enabled.

(2) Command Data

The protocol for command data reception is as shown in FIG. 44.

(3) Image Data

The protocol for the reception of a print start command to reception of image data is as shown in FIG. 45.

When the process shown in FIG. 46 is executed to the end during communication between the host system and the image formation apparatus, the host system determines that there is an error in the hardware of the communication system and recovery processing must be performed.

The image data sent from the host system is temporarily stored in the buffer in the apparatus and is then printed. When the data transmission speed is lower than the printing speed and the buffer becomes empty, printing is interrupted. When more image data is sent and stored in the buffer, printing is resumed. If image data is not stored in the buffer within 3 minutes, the head is capped. When image data is sent and stored in the buffer after the head is capped, printing is resumed.

The types of and countermeasures for errors occurring in the image formation apparatus according to the present invention will be described below.

(1) Paper Jam

A paper jam occurs during printing or feeding of paper, or a paper jam is detected when the power is turned on.

Error Code:

State: OFF LINE mode is set.

Check printing cannot be performed.

Countermeasure is described in the following Table 12.

(2) No Paper

Paper has been used up during printing or feeding of paper, or no paper is detected when the power is turned on.

Error Code:

State: OFF LINE mode is set.

Check printing cannot be performed.

Counermeasure is described in the following Table 13.

When no paper is detected during printing, the image data in the buffer is printed first and then printing is interrupted.

(3) Paper Set Error

The paper is not set correctly.

Error Code:

State: OFF LINE mode is set.

Check printing cannot be performed.

Countermeasure:

(4) No Ink

Ink is not supplied in an amount sufficient to perform printing.

Error Code: (in the order of B, C, M and Y)

State: OFF LINE mode is set.

Check printing cannot be performed.

Recovery cannot be performed.

Countermeasure is described in the following Table 14.

(5) Setting Error of Recording Heat Unit

When power is turned on, it is found that no recording head unit is set.

Error code:

State: OFF LINE mode is set.

Checking printing cannot be performed.

Recovery cannot be performed.

Countermeasure is described in the following Table 15.

The apparatus has a temperature sensor and is operated as follows in accordance with the detected temperature.

(1) Power Failure

A voltage drop of AC is detected.

Countermeasure is described in the following Table 17.

(2) Overload

A current exceeding the rated current flows from the DC power supply in the apparatus.

Countermeasure is described in the following Table 18.

The state is different in accordance with the cause of overload.

(1) Mechanical Controller MC Hardware Error

An error which cannot be recovered has occurred in a mechanical part other than the recording head assembly.

Countermeasure is described in the following Table 20.

(2) Head Assembly Mechanism AM Hardware Error

An error which cannot be recovered has occurred in the recording head assembly.

Countermeasure is described in the following Table 21.

Maintenance of the image formation apparatus according to the present invention will now be described.

Switches used for maintenance are arranged on the board in the card rack. The arrangement used is as shown in FIG. 39.

(1) Purpose

Four test patterns are available for the check printing functions. One of the four test patterns can be selected by a test pattern switch in the card rack. The test patterns are used for the purposes shown in FIG. 40.

(2) Function

Used to confirm that the apparatus is in the following states:

No error is present.

OFF LINE mode is selected.

BUSY lamp is not ON.

Head is capped.

Paper feed unit is closed.

One of the four patterns is selected using the test pattern switch in the card rack.

The CHECK switch on the display panel is depressed.

" " is displayed on the display panel, and the BUSY LED is turned on. After about 15 seconds, check printing is started.

After check printing is ended, if the apparatus is in the OFF LINE mode and no error has been produced, normal operation can be continued.

Ink ejection positions of the respective colors are adjusted to eliminate color misregistration. A registration adjustment switch is used to change the ejection position, and printing shift is confirmed by the test pattern (number 0).

(1) Registration Adjustment Switch

A horizontal registration adjustment switch is used to adjust the printing position in a direction (horizontal) perpendicular to the paper feed direction. A vertical registration adjustment switch is used to adjust the printing position in a direction (vertical) parallel to the paper feed direction.

a. Horizontal Registration Adjustment Switch.

One switch is provided for each color.

When the indication value of each switch is increased, the printing position is shifted to the right (when the paper feeding direction is upward). When the indication value of each switch is decreased, the printing position is shifted to the left (when the paper feeding direction is downward).

Adjustment can be made in units of 1/8 mm and within a range of -7/8 mm to +7/8 mm.

b. Vertical Registration Adjustment Switch

Each color head is vertically divided into two parts. For the color, therefore, two adjustment switches are provided for the upper and lower heads, respectively. The switch for the upper head does not influence the printing position of the lower head, and vice versa.

Each of the switches for the upper and lower heads further consists of two switch elements; one for coarse adjustment (adjustment in units of 1/2 mm) and the other for fine adjustment (adjustment in units of 1/32 mm).

When the indication value of each switch is increased, the printing position is shifted downward (when the paper feeding direction is upward). When the indication value of each switch is decreased, the printing position is shifted upward (when the paper feeding direction is upward).

Adjustment can be made in units of 1/32 mm and within a range of -4 mm to +(3+31/32) mm.

FIG. 41 shows the above relationship.

(2) Procedures of Adjustment

Step 1

All the horizontal registration adjustment switches are set a reference position (7).

Step 2

All the vertical registration adjustment switches are set at reference position (coarse adjustment: 8, fine adjustment: 0).

Step 3

The test pattern switch is set at 0.

Step 4

The CHECK switch is depressed to perform check printing.

Step 5

The polygonal line pattern portion of the test pattern obtained in step 4 is checked.

Deviations of the cyan, magenta, and yellow lines from the black line to the right or left are measured.

Step 6

The horizontal registration adjustment switches of cyan, magenta and yellow are operated in accordance with the results obtained in step 5.

For example, if the cyan line is shifted from the black line by 2 dots (2/8 mm) to the left, the cyan horizontal registration adjustment switch is set to 9.

Step 7

The CHECK switch is depressed again to perform check printing. If adjustment is not sufficient, steps 5 and 6 are repeated.

When there is no more horizontal deviation of the lines of the respective colors from the black line, the process advances to step 8.

Step 8

The portion of the test pattern printed by the upper head in step 7 is checked.

Particular portions to be checked are a folded portion of the polygonal pattern, and a linear pattern.

The amounts and directions (upward or downward) of vertical deviations of the cyan, magenta and yellow lines from the black line are measured.

Step 9

The cyan, magenta and yellow color outputs are adjusted by operating the upper head vertical registration adjustment switches in accordance with the results obtained in step 8.

Step 10

The CHECK switch is depressed to perform check printing. If adjustment is still insufficient, steps 8 and 9 are repeated.

When there is no further vertical color misregistration for the portions printed by the upper heads, the process advances to step 11.

Step 11

The portions of the test pattern printed by the lower heads in step 10 are checked.

The amounts and directions (upward or downward) of vertical deviations of the cyan, magenta and yellow lines from the black line are measured.

Step 12

The lower head vertical registration adjustment switches for black, cyan, magenta and yellow are operated in accordance with the results obtained in step 11.

Step 13

The CHECK switch is depressed to perform check printing. If adjustment is not yet satisfactory, steps 11 and 12 are repeated.

The head voltage (Vop) set for ejecting ink is different in each recording head unit (even in each unit for the same color).

Therefore, when the recording head unit is replaced, Vop adjustment must be peformed in the following manner (FIGS. 42 and 43).

Specified digital tester terminals are inserted into Vop monitor terminals of a replacement recording head unit (left (black) -, right (red) +).

While a Vop monitor switch is depressed, the volume is set at a voltage indicated at the upper portion of the recording head unit.

The recording surface positioned with respect to the recording head unit can be formed also in the following manner.

In the example described above, the fan 138 arranged in the assembly 130 is operated to blow air from the assembly 130 to the platen 392 in order to facilitate vacuum suction of the recording paper P toward the platen 392. However, the fan 138 can be operated in a reverse direction so as to draw the recording paper P to the front surface of the assembly 130. In this case, the height of the horizontal linear projections 115 at the upper and lower portions of the recording head is set higher than the height of the recording head. The operation of the fans 390F for drawing the recording paper P to the platen 392 is then stopped. With this arrangement, the recording paper P can be reliably drawn to the front surface of the assembly 130, and the linear projections 115 can keep an optimal distance between the surface of the recording paper P and the recording head. Thus, stable printing on the recording paper P can be performed. The fan 138 is continuously operated, whereas the recording head heater is controlled to keep the temperature in the assembly 130 constant in accordance with the detection result of the temperature sensor in the recording head assembly 130.

According to the present invention as described above, an image formation apparatus with the following advantages can be provided. More specifically, a suction airflow is formed using a fan and a member which maintains a proper distance to a liquid jet port of a recording means and against which a recording medium abuts, so that fine ink mist produced from ejected ink droplets is trapped, and the trapped mist is absorbed by an absorbing member. The absorbing member can be replaced with a new one, thereby exhausting the ink mist outside the apparatus.