Dot Matrix Condition Display Device for Photocopiers

The present invention relates to a display device for a photocopier.

A photocopier is generally equipped with various dislay devices for informing the user of various troubles occuring during use. Examples of conventional display devices of the type described above are shown in FIGS. 1 and 2. In the display device shown in FIG. 1, holes 4 are formed in the vicinities of symbol marks printed on a symbol panel 2. Display is performed by lighting lamps 6 respectively arranged below these holes 4. Each of the symbol marks has its own meaning. For example, the symbol "ADD PAPER" associated with reference numeral 8 means that paper must be supplied, and that "READY" of reference numeral 10 means copying may be started at any time. The display device shown in FIG. 2 employs a screen 12 with symbol marks and display phrases corresponding to these symbol marks in place of the symbol panel 2. This device is so constructed that the symbol marks and the display phrases are lit by lighting lamps 14 arranged below the screen 12.

However, the display device for a photocopier of such a construction had drawbacks. For example, the area occupied by the display device becomes larger as the kinds of displays become greater. Although this does not pose a serious problem for a large photocopier, this limits the number of kinds of displays which may be provided by a small photocopier, precluding the display of all the functions.

The present invention has been made in consideration of this and has for its object to provide a display device so that even if a photocopier is small, a large quantity of information may be provided to the user. Also, the construction of the display devices is simple, and the display is of low cost.

In order to achieve the above and other objects, the present invention provides a display device for a photocopier which detects the various troubles of the photocopier by a detector and displays information about these troubles. A display is provided for displaying symbol marks corresponding to the various troubles of the photocopier. A pattern generator stores the symbol marks. A control device receives at least one detection signal from a detector and outputs a control signal to read out a pattern corresponding to the detection signal from the pattern generating means. A display driver receives the output signal from the control device and drives the display to display a corresponding symbol mark.

According to the display device for a photocopier of the present invention, various types of mark displays are realized by simply storing various symbol marks in a pattern generating means, thereby allowing the area occupied by the display unit to be made smaller. Thus, a display unit which is extremely easy for the user to observe may be provided. Further, the number and kinds of symbol marks to be stored in the pattern generator may be changed. A display device which may be generally used for all models of photocopiers may thus be provided.

Other objects and features of the present invention will be apparent from the following description taken in connection with the accompanying drawings.

FIGS. 1 and 2 are perspective views of conventional display devices for a photocopier;

FIG. 3 is a perspective view of an overall photocopier incorporating one embodiment of the present invention;

FIG. 4 is a schematic sectional view of the device shown in FIG. 3;

FIG. 5 is a plan view illustrating one embodiment of the control panel of the display device for a photocopier according to the present invention;

FIG. 6 is a schematic view illustrating one embodiment of the pattern display unit of the display device for a photocopier according to the present invention;

FIG. 7 is a block diagram illustrating one embodiment of the control unit for the display device of the present invention;

FIG. 8 is a view illustrating the stored contents of the pattern generator used in the control unit shown in FIG. 7;

FIG. 9 is a detailed block diagram of the control unit shown in FIG. 8;

FIG. 10 is a detailed block diagram of the display control unit shown in FIG. 8;

FIGS. 11A through 11C are views illustrating the operating principles of the display device for a photocopier according to the present invention, wherein FIG. 11A shows the symbol display calling for supply of more paper ("ADD PAPER"), FIG. 11B shows the symbol display for a jammed condition ("PAPER JAM"), and FIG. 11C shows the symbol display for the ready condition of the photocopier ("READY");

FIG. 12 is a plan view illustrating another embodiment of the control panel of the display device according to the present invention;

FIG. 13 is a schematic view illustrating one embodiment of the pattern generator;

FIG. 14 is a view illustrating an example of the stored contents of the pattern generator used in the embodiment shown in FIG. 12;

FIGS. 15A and 15B are views illustrating the operating principles of the pattern generator shown in FIG. 12, wherein FIG. 15A shows the symbol display and the phrase display for supplying more paper, and FIG. 15B shows the symbol display and the phrase display for a paper jam;

FIG. 16 is a plan view illustrating still another embodiment of the control panel of the display device according to the present invention;

FIG. 17 is a schematic view illustrating an embodiment of the pattern display unit according to the embodiment shown in FIG. 16; and

FIGS. 18A through 18D are views illustrating the operating principles of the pattern display unit shown in FIG. 17, wherein FIG. 18A shows the phrase display and the symbol display for "PAPER JAM," FIG. 18B shows the phrase display for "ADD PAPER," FIG. 18C shows the phrase display for "WAIT," and FIG. 18D shows the phrase display for the "READY" condition of the photocopier, respectively.

FIG. 3 is a perspective view of a photocopier to which a display device of the present invention is to be applied. FIG. 4 is a schematic sectional view of the photocopier shown in FIG. 3.

Referring to FIG. 3, a control panel 20 having a display unit 18 is disposed at one upper side edge of a photocopier 16. A manuscript table 22 of the photocopier 16 reciprocates in the direction shown by arrow X as required. A detachable tray 24 is mounted at the left side of the photocopier 16 as shown in FIG. 4, and a cassette 28 holding paper copying sheets 26 is mounted to the right side of the photocopier in the figure.

Inside this photocopier 16 are incorporated a paper feeding mechanism 30 for feeding the paper copying sheets 26 in the cassette 28, a copying mechanism 32, a carrying mechanism 34, a fixing mechanism 36, a photosensitive body 38, a developer 42 containing toner 40, a cleaning mechanism 44 for the photosensitive body 38, an illumination system 46, an optical fiber lens 48, a charger 50, carrying rollers 52, and a motor 54 for synchronously moving the manuscript table 22 and rotating the photosensitive body 38. A paper-absence detector 56 (e.g., a microswitch) is disposed at the upper middle part of the paper feeding cassette 28. A paper jam detector 58 (e.g., a microswitch) is disposed at the left side of the fixing mechanism 36. A temperature detector 60 (e.g., thermistor) is arranged at the upper part of the rollers 52 for exhaustion located in the vicinity of the edge of the tray 24. In this type of device, the manuscript placed on the manuscript table 22 is illuminated by the illumination system 46, and an image of it is formed on the surface of the photosensitive body 38 through the optical fiber lens 48. Thereafter, the paper copying sheets 26 inside the paper feeding cassette 28 are fed one by one by the paper feeding mechanism 30 and are guided below the photosensitive body 38. A photosensitive image developed by toner 40 inside the developer 42 is copied on the paper copying sheet 26 by the copying mechanism 32. The sheet 26 is guided to the fixing mechanism 36 through the carrying mechanism 34 for fixing and is exhausted to the tray 24. After the copying operation, the photosensitive body 38 is cleaned by the cleaning mechanism 44 which is positioned by the charger 50.

The control panel 20 has, as shown in FIG. 5, a display unit 18, a counter display unit 62, ten keys 64, a copy button 66, and a power source switch 68. The display unit 18, more particularly, comprises a liquid crystal panel 70 of the dot matrix type, as shown in FIG. 6.

An embodiment of the control system for this display unit 18 will be described with reference to FIG. 7. Referring to this figure, reference numeral 72 denotes a control unit and comprises, for example, a one-chip microcomputer incorporating an input/output port (I/O port) 84, a read-only memory (ROM) 86, a random-access memory (RAM) 88, and a central processing unit (CPU) 90, as shown in FIG. 9. To this control unit are applied the output signals of the paper-absence detector 56, the paper jam detector 58 and the temperature detector 60, as well as the output signals of the ten keys 64 and the copy button 66. This control unit is thus constructed to process these signals and to output predetermined control signals. Reference numeral 74 denotes a display control unit which drives, according to the control signal from the control unit 72, the display unit 18 and the counter display unit 62. This display control unit 74 comprises, for example, a one-chip microcomputer incorporating the I/O port 84, the ROM 86, the RAM 88, the CPU 90, a decoder 92, and a liquid crystal driver 94, as shown in FIG. 10.

Reference numeral 76 denotes a pattern generator and comprises, for example, the ROM 86 which stores a symbol mark 78 (see FIG. 8) representing "ADD PAPER," a symbol mark 80 representing "PAPER JAM," and a symbol mark 82 representing "READY." The contents of the pattern generator 76 are read out as binary code signals by address selection signals from the display control unit 74, decoded by the display control unit 74, and are reproduced by lighting the predetermined liquid crystal cell in the display unit 18. Preferably, many kinds of symbol marks are prepared as required and the detectors are disposed in correspondence therewith.

The mode of operation of the device of the construction as described above will be described with reference to FIGS. 11A through 11C.

When the paper copying sheets 26 in the cassette 28 are used up during the copying operation, the paper-absence detector 56 operates, and an output signal from this paper-absence detector 56 is applied to the control unit 72. The control unit 72 process the output signal from the paper-absence detector 56 and supplies an "ADD PAPER" display signal to the display control unit 74. The display control unit 74 outputs a signal for selecting the "ADD PAPER" symbol mark 78, reads out this mark 78, and supplies to the display unit 18 a display signal decoded by the read signal. Thus, the symbol mark 79 equivalent to the mark 78 stored in the pattern generator 76 is displayed at the display unit 18. The user is thus capable of recognizing that more paper copying sheets must be added and responding to this need (FIG. 11A).

When the copied paper sheet is jammed in the vicinity of the exhausting section, the paper jam detector 58 interposed between the carrying rollers 52 and the fixing mechanism 36 operates and its output signal is supplied to the control unit 72. A control signal is thus output from the control unit 72 to actuate the display control unit 74. Then, the paper jam mark 80 in the pattern generator 76 is selectively read out, and a drive signal is supplied to the display unit 18. The symbol mark 81 representing "PAPER JAM" is thus displayed. When the user sees this, an inspection can be performed and the jammed paper can be removed (FIG. 11B).

When further copying operation is possible, the mark 82 in the pattern generator 76 is selected. Then, a symbol 83 representing "READY" is displayed at the display unit 18. When the user sees this, he can depress the copy button (FIG. 11C).

In addition to this, various other symbol marks stored in the pattern generator 76 may be displayed as the case may require. It is preferable that the meanings of the symbol marks be clarified in the instruction manual.

FIG. 12 shows another embodiment of the display device of the present invention. This embodiment represents a case in which the display unit 18 arranged in the control panel 20 is transversely divided into two regions 18.sub.1 and 18.sub.2. This display unit 18 comprises, for example, a symbol mark display unit 18.sub.1 and a phrase display unit 18.sub.2 representing the meanings of these symbol marks as shown in FIG. 13. These units comprise a liquid crystal matrix panel. The liquid crystal cells of these display units 18.sub.1 and 18.sub.2 are driven and controlled by the two kinds of signals (synchronized with each other) output from the display control unit 74. Although the construction of the control system is substantially the same as that of the embodiment described above, the contents stored in the pattern generator 76 differ slightly from those of the embodiment described above. For Example, in addition to the symbol marks 78, 80 and 82, display phrases 96, 98 and 100 "ADD PAPER," "PAPER JAM," and "READY," are also stored as shown in FIG. 14. The various stored contents are selected based on a command signal from the display control unit 74 and are displayed at the display units 18.sub.1 and 18 .sub.2 to be associated with each other.

The mode of operation of the embodiment shown in FIG. 12 will be described with reference to FIGS. 15A and 15B.

When an output is supplied from the paper-absence detector 56, the symbol marks 78 and 96 are sequentially selected according to the operations of the control unit 72 and the display control unit 74. The symbol mark 79 is displayed at the display unit 18.sub.1 and a display phrase 97, "ADD PAPER" is simultaneously displayed at the display unit 18.sub.2 (FIG. 15A).

In the case of a paper jam, a mark 81 and a display phrase 99 "PAPER JAM" are simultaneously displayed at the display unit 18 (FIG. 15B).

In this embodiment, the symbol mark as well as the display phrase representing its meaning are simultaneously displayed. Due to this, in addition to the advantages obtained in the embodiment shown in FIG. 7, this embodiment presents further advantages in that the user may directly recognize the nature of the trouble and may take fast measures.

FIG. 16 shows a still further embodiment of the display device for a photocopier according to the present invention. According to this embodiment, the display unit 18 arranged in the control panel 20 is divided into two vertically arranged regions 18.sub.3 and 18.sub.4. In this display unit 18, the upper region 18.sub.3 comprises a liquid crystal matrix panel for a phrase display unit as shown in FIG. 17, and the particular symbol marks 102, 104, 106 and 108 are displayed at the lower region 18.sub.4 making up a symbol mark display unit.

To the display control unit are separately supplied a signal for driving the liquid matrix panel and a signal for driving the liquid crystal for a particular symbol mark.

Accordingly, it is possible to simultaneously drive both the regions 18.sub.3 and 18.sub.4 or to drive either of these separately. Since the construction of other parts is the same as that of the embodiments described above, the description thereof will be omitted.

The operation of the device of this embodiment will now be described with reference to FIGS. 18A through 18D. When the paper jam detector 58 operates and a command signal is output from the control unit 72, respective drive signals are output from the display control unit 74. The phrase 99, "PAPER JAM" is displayed at the phrase display unit 18.sub.3 so that the symbol mark 102 at the symbol mark display unit 18.sub.4 may be recognized (FIG. 19A). When there is no more paper, by the operation described hereinabove, the display phrase 97, "ADD PAPER" is displayed at the phrase display unit 18.sub.3 so that the mark 104 at the symbol mark display unit 18.sub.4 may be recognized (FIG. 18B).

During the warm-up operation, a display phrase 109, "WAIT," is displayed at the phrase display unit 18.sub.3 so that the mark 108 at the symbol mark display unit 18.sub.4 may be recognized (FIG. 18C).

When the photocopier is ready to start copying, the display phrase 112, "READY," is displayed at the phrase display unit 18.sub.3 so that the mark 106 at the symbol mark display unit 18.sub.4 may be recognized (FIG. 18D).

In a similar manner, various other pairs of display phrases and symbol marks are simultaneously displayed at the upper and lower regions of the display unit according to the various troubles. When a trouble occurs which does not correspond to any of the display phrases for symbol marks 102, 104, 106 and 108, the upper region of the display unit 18 is selectively driven so that the display phrase alone is displayed.

According to the above embodiment, it is possible to display the kinds of troubles which most frequently occur with both display phrases and symbol marks at both the upper and lower regions, and to display the kind of troubles which occur less frequently with display phrases at the upper region alone. Accordingly, a large quantity of information may be provided to the user by simply increasing the stored contents of the pattern generator.

Although the display phrases were all in English in the above embodiments, it is possible to simultaneously store phrases in French, German, Chinese and so on to allow selective display according to the market for the products. With this construction, there is no need to change the printing of the display unit of the control panel according to the language of the market for the product as has been the case with conventional display devices.

Although a liquid crystal display unit was used in the above embodiments, it is possible to use an LED (light-emitting diode) or a photoelectric conversion element, or the like.

It is also possible to dispose a plurality of detectors in the carrying path of the paper copying sheet within the photocopier and to store display phrases representing the positions of these detectors, so that the kinds of troubles as well as the positions may be displayed.