Sheet Sorter Apparatus

The present invention relates to sheet sorter apparatus and particularly to a machine for sorting sheets produced by a duplicator, such as a xerographic copier, and arranging or collating the sheets into sets.

The invention is especially suitable for use in providing a low cost, compact sorter which may be associated with a copier by being placed adjacent to the copier to receive duplicated sheets dispensed by the copier.

In compact sorters, a stack of trays is provided for receiving the sheets to be sorted into sets. These trays are closely spaced to each other in a stack. The trays must be separated in order to provide access between them for clearing jams, servicing and maintenance of the sorter. In U.S. Pat. No. 4,433,837 issued to R. F. Romanowski on Feb. 28, 1984 as in other compact sorters, for example the sorter of U.S. Pat. No. 4,332,377 issued June 1, 1982, the rear ends of the trays are in close proximity and may be disposed on racks which limit their accessibility and the extent to which the trays can be separated.

Another problem with compact sorters resides in the mechanism for shifting the trays. Various types of tray shifting mechanisms have been suggested as shown in the above identified patents and also in the following patents which collectively provide the technological background for this invention: U.S. Pat. Nos. 3,356,362 issued Dec. 5, 1967; 3,721,435 issued Mar. 20, 1973; 3,788,640 issued Jan. 29, 1974; 3,879,032 issued Apr. 22, 1975; 3,953,023 issued Apr. 27, 1976; 4,343,463 issued Aug. 10, 1982; 4,397,461 issued Aug. 9, 1983; 4,466,608 issued Aug. 21, 1984; and 4,478,406 issued Oct. 23, 1984. The mechanism provided by this invention serves to shift the trays while they remain supported as cantilevers without any contact or restraint between their free ends, thereby facilitating the use and operation of the sorter.

It is the principal object of the present invention to provide improved sheet sorter apparatus which is easy to operate and use, particularly whenever access to sheets within the sorter is necessary, for example to clear sheets jammed in the sorter for repair, maintenance and other purposes.

It is another object of the present invention to provide an improved sheet sorter which is compact in size so as to be suitable for use with small bench top xerographic copiers or duplicators and which may be fabricated at low cost.

Briefly described, the invention provides apparatus for sorting sheets as they arrive, one at a time from the outlet of a copying machine or the like. The sorter uses a plurality of stacked trays. The trays have pins extending outwardly from the side edges thereof, preferably near the forward end of the trays. The pins are spaced from each other along the side edges. The sorter is supported in a frame having upright support plates disposed along the side edges of the trays. The plates have pairs of slots, generally paralleling each other, into which the pins extend. The slots have walls upon which the pins bear and upon which the trays are supported as cantilevers with the rearward ends of the trays spaced from each other in generally parallel relationship. A tray shifting mechanism is engagable with the pins and moves the trays, one at a time, along the slots through a region adjacent the copier outlet where adjacent ones of the trays are separated so that the sheets are received on the lower one of the separated trays. The mechanism translates the stack of trays, which are retained in a carriage, upwardly or downwardly depending upon the direction in which the trays are shifted through the gap.

The foregoing and other objects, features and advantages of the invention, as well as a presently preferred embodiment thereof, will become more apparent from a reading of the following description in connection with the accompanying drawings in which:

FIG. 1 is an elevational rear view of a sorter embodying the invention;

FIG. 2 is a sectional, front elevational view of the sorter shown in FIG. 1, the section being taken along the line 2--2 in FIG. 1;

FIG. 3 is a fragmentary top view showing the front end of the sorter shown in FIGS. 1 and 2;

FIG. 4 is a fragmentary view of a typical tray showing a pin assembly thereon;

FIG. 5 is an elevational view showing the pin assembly and tray of FIG. 4;

FIG. 6 is an elevational view of the linkage assembly of the tray shifting mechanism used in the sorter shown in FIGS. 1, 2 and 3;

FIG. 7 is a top view of the linkage assembly shown in FIG. 6, the view being shown partially in section so as to illustrate the pivotal connection between links;

FIG. 8 is a diagrammatic view showing the drive system for the tray shifting mechanism; and

FIGS. 9A, B, C and D illustrates the link mechanism in four positions as it translates a tray upwardly through the gap into which sheets are fed so that they can be received on the tray at the bottom of the gap.

Referring to the drawings, there is shown a frame 10 having side plates 12 and 14. Inwardly from the side plates 12 and 14 are support plates 16 and 18. The upper parts of these plates may be backed by strengthening plates 16a and 18a. Each of these support plates, as illustrated for the support plate 16, has a forward slot 20 and a rearward slot 22. These slots are generally parallel to each other. The slot 22 is wider than the slot 20. Each of these slots has an upper portion 20a and 22a, a lower portion 20b and 22b and a circular portion 20c and 22c. The support plates 16 and 18 have carriage members 24 (See FIGS. 2 and 3) slidably mounted in grooves along the edges of the support plates as shown at 27 and 29 in FIG. 3. The carriage members 24 are internally open and are essentially frames having side walls 28 and 30 and top and bottom walls 32 and 34.

The sorter is shown by way of example with ten trays 38 in stacked relationship. These trays have central indented regions 40 which allow the paper to bow to increase its lateral strength. The trays also have ears 42 and 44 at their rearward ends to restrain the sheets from moving laterally off the trays. These ears can be made of wire, as shown, or can be integral parts of the trays. The trays can be of integral construction, i.e., all plastic, metal or wire forms. The trays also have lips 46 providing L-shaped forward ends to prevent the paper sheets from slipping off the trays from the front thereof. The trays have assembled along the opposite side edges thereof, pin assemblies 50 as best shown in FIGS. 4 and 5. These pin assemblies, which are referred to herein also as "pin means", consist of bars 52 having rollers 54 in which metal pins 56 are inserted. The rollers are spacing rollers which define the distances between adjacent trays 38 in the stack. The rollers also are disposed in the slots 20 and 22. The pins 56 extend outwardly of the support plates 16 and 18 as shown in FIGS. 1 and 3. The diameter of the roller is approximately equal to the diameter of the slot 20; there being sufficient clearance to allow the rollers to translate and rotate in the slots. The rearward one of the roller pairs 54 is spaced so that it bears against the rearward wall 58 of the slot 22. Because the rollers bear against the walls of the slot and rest one upon the other, the trays are cantilevered in the slots so that their rearward ends thereof are free and spaced parallel to each other. Since the rearward slot 22 is displaced vertically upwardly from the forward slots 20, the trays are tilted upwardly toward the rear.

An important feature of the invention is that any tray or stack of trays can be grasped manually and tilted upwardly, pivoting about its forward rollers 54. This enables a large access space to be provided between trays. Paper can be cleared from between the trays and access also had for repair and maintenance purposes.

In effect, the slots provide a dual track along which the stack and trays and individual trays can be moved past a gap defined by the circular portions 20c and 22c of the slots. The document or copy from the duplicator which is located to the left as shown in FIG. 2 is advanced across a plate 62 between feed rolls 64, which may be motor driven, from the same drive motor which drives the sorter by means of pulleys or other mechanisms (not shown). The outlet of the copier thus is ahead of the plate 62 and of the feed rolls 64. The copy sheet is driven by the rolls onto the tray 38 at the bottom of the gap. This is the tray 38a shown in FIG. 2. In the position of the apparatus in the figures, nine of the trays are above the gap and one tray 38 is below the gap. A sorter is assumed to have received a sheet on tray 38a which will then be driven upwardly to be the last tray above the gap. In the next operation, the trays will be shifted downwardly, one at a time until all ten trays are below the gap. The stack of trays is driven upwardly and downwardly one at time, so as to collate ten sheets during a downward displacement of the stack and the next ten sheets during an upward displacement of the stack.

The carriage assures that the entire stack will move in unison as a tray is shifted across the gap. The shape of the slots 20 and 22 assures that the stack will be supported. It will be observed from FIG. 8 that the upper portions 20a and 22a of the vertical slots meet the intermediate circular slots 20c and 22c at a position past the vertical. Assuming the vertical is at zero degrees, the slot portions 20a and 20c and 22a and 22c meet about 15 degrees before zero degrees. The junction of these slots then forms indentations or ledges 66 and 68. The stack of trays is maintained by the carriage on these ledges below the top wall 32 of the carriage. A leaf spring 70, attached to the top wall 32, is engaged with the bars 52 of the pin assemblies 50 and urges the stack against the ledges 66 and 68. There is, of course, a similar mechanism including another spring in the carriage on the side of the machine where the other support plate 18 is located.

The manner in which the entire stack is shifted, and the carriage arrangement for retaining and moving the stack in unison, is similar to the mechanism for the same purpose which is described in the Romanowski Pat. 4,433,837, referenced above.

The mechanism for shifting the trays is an eccentric translating mechanism provided by a four bar linkage assembly 72 best shown in FIGS. 6 and 7, but also shown in dash lines in FIGS. 2 and 8. The linkage assembly 72 has a pair of crank links 74 and 76 with axes of rotation 78 and 80. These crank links are driven by pulleys 82 and 84 which are connected thereto by shafts 86 and 88. The pulleys are driven synchronously by a belt 90. The belt is entrained also around a dual diameter coaxial drive pulley 92. The drive pulley 92 is driven by another belt 94 which is connected to a pulley 96 on the output shaft 98 of a motor 100. The coaxial pulley 92 has a shaft 104 extending laterally across the copier to the opposite frame wall which is connected through a similar arrangement of belts and pulleys which are identified by like reference numerals.

Returning to the linkage assembly 72, the crank links 74 and 76 are pivotally connected at pin bearings 106 and 108 to a translational link or bar 110. This bar has a cam angle or radius indicated at 15 degrees so as to remain below the upper edge of the support plates 16 and 18. The link 110 is formed with slots or notches (key slots) 112 and 114. These slots have tapered outer regions and a neck which is extends over the pivotal axis of the bearings 106 and 108. The key slots allow positive engagement with tray roller pins (lead-in). The translational link is eccentrically driven about the axes 78 and 80 which are also the axes of the pulleys 82 and 84.

The operation of the shifting mechanism will be apparent from FIGS. 9A to 9D. It will be appreciated that these figures are taken generally along the line 9--9 in FIG. 3. In FIG. 9A the mechanism 72 initiates rotation counterclockwise. The key slots 112 and 114 receive the pins and carry the tray upwardly with the rollers 54 travelling around the intermediate circular portions of the slots 20c and 22c. The gap between the adjacent trays gradually closes as shown in FIGS. 9B and 9C. As shown in FIG. 9D, the rollers are in engagement and the adjacent trays are spaced apart by the rollers 54, as the key slots leave the pins. The lower rollers are on the ledges 66 and 68 (FIG. 8). By reversing the rotation direction of the mechanism 72 a tray at the bottom of the upper portion of the stack is shifted to the lower portion where it will be retained in the slot portions 20b and 22b upon the lower wall 34 of the carriage 24.

From the foregoing description, it will be apparent that there has been provided an improved sorter which may readily be implemented at low cost, since it requires only a limited number of parts. The dual track arranged afforded by the slots 20 and 22 maintain the trays in stacked relationship parallel to each other and cantilevered rearwardly for ready access and manipulation. Of course, variations and modifications in the herein described sorter, within the scope of the invention, will undoubtedly suggest themselves to those skilled in the art. Accordingly, the foregoing description should be taken as illustrative and not in an eliminating sense.