GB2130562A - Copy sheet inverter with adjustable stop mechanism - Google Patents

Abstract

A sheet inverter/reverser (44) for use in a copier/duplicator during a duplex mode of operation or whenever copy sheet reversal is desired comprises resilient, ring-shaped, stop members (74, 75) to limit the extent to which sheets enter a chute (65) before being conveyed out of the inverter/reverser. The stop members are mounted on a yoke element (77) for movement up or down to lengthen or shorten the working range of the receptacle automatically in response to a signal indicative of a sheet dimension. The yoke 77 is attached to a belt 80 passing over rollers 81, 82 driven by a reversible motor operated by switches actuated by movement of width guide plates on the copy sheet supply trays. <IMAGE>

Description

SPECIFICATION Copy sheet inverter with adjustable stop mechanism This invention relates to a sheet inverter mechanism for use in a reproduction machine or copier, and more particularly to a system for automatically adjusting a sheet limiting stop in response to the size of the copy sheets being processed.

Modern day high speed reproduction machines or copiers enable the operator to perform a variety of different copy functions such as simplex copying, duplex copying, sorting, collating, stapling, and the like. However, the addition of these various features often comes at the expense of additional burdens on the user or operator in the form of machine set ups and adjustments that are required before the feature can be implemented. To compound the burdens has been the strategy to devise a machine international in nature, that is, a machine which may utilize various copy sheet sizes indigenous to the various countries of the world. For example, in the United States, the current copy size is 216 x 279 mm, whereas throughout the world the international sizes B4, B5 and A4 are standard sizes.The goal, to enable a machine to accommodate a multitude of sheet sizes such as exemplified above, has in some cases led to the imposition on the user or operator of certain manual tasks that must be performed before the machine may be used. In some cases, this requirement may not only be burdensome and time consuming but may also, because of the nature of the machine, be difficult, as for example, where the part to be adjusted is not easily accessible.

In the prior art, such as illustrated in U.S. Patent No. 4,078,789, an adjusting member is utilized in a sheet inverter in order to accommodate documents of various sizes. However, there is no provision for varying the positioning of the adjusting -z~mber automatically or to move the same in accordance with a measured parameter of a document sheet, at some other location in the host machine. In another prior art patent, U.S. Patent No. 3,856,295, a resilient stop member is adapted to be moved into and out of a sheet path, but there is no provision for moving the stop member along the path in accordance with sheet size.

Therefore, it is the principle object of the present invention to simplify sheet handling of a copier wherein sheet inversion is necessary, say for duplex operation, by conditioning a sheet inverter/reverser automatically to accommodate copy sheets of various sizes and in accordance therewith.

The invention is directed to a copy sheet inverter reverser for copier which is capable of producing duplex or two sided copying, wherein the inverter is arranged to receive copy sheets having a first side copied thereon and to re-insert sheets into the paper path for proper orientation of output copy. In accordance with the invention, a resilient stop member is interposed into the path of the copy sheets which are driven into a chute to limit the extent to which the sheets are so driven. The stop member serves as a springboard to assist in the reverse driving of the sheet out of the chute for return to the copier processor, or out of the copier if simplex copying has been programmed and it is desired that the sheets be inverted as part of the output orientation.The stop member is movable relative to the paper path in the chute in order to accommodate sheets of many different widths and such movement is under control of means for sensing the width of copy sheets before entering the inverter mechanism.

Other objects and advantages of the invention will become apparent after reading the description taken in conjunction with the accompanying drawings wherein: Figure 1 is a schematic view of a reproduction machine or copier incorporating the automatic inverter/reverser system of the present invention; Figure 2 is an isometric view of the inverter reverser shown in the machine of Figure 1 incorporating the present invention; and Figure 3 is an elevational view of the inverter reverser.

For a general understanding of the features of the present invention, reference is had to the drawings.

In the drawings, like reference numerals have been used throughout to designate identical elements.

Figure 1 schematically depicts the various components of an illustrative electrophotographic printing machine incorporating the copy processing and jam monitoring system of the present invention therein.

It will become evident from the following discussion that the invention is equally well suited for use in a wide variety of printing machines and is not necessarily limited in its application to the particular embodiment shown herein.

Inasmuch as the art of electrophotographic printing is well known, the various processing stations employed in the Figure 1 printing machine will be shown hereinafter schematically and their operation described briefly with reference thereto.

As shown in Figure 1, the illustrative electrophotographic printing machine 5 employs a belt 6 having a photoconductive surface thereon. Preferably, the photoconductive surface is made from a selenium alloy. The belt 6 moves in the direction indicated by the arrow 7 to advance successive portions of the photoconductive surface through the various processing stations disposed about the path of movement thereof. Successive portions of the photoconductive surface pass through charging station A whereat a corona generating device, indicated generally by the reference numeral 8, charges the photoconductive surface to a relatively high substantially uniform potential.

A charged portion of the photoconductive surface is advanced through imaging station B whereat it is exposed to imaging light rays of a document 0 handled in a document handling unit, indicated generally by the reference numeral 10. The unit 10 positions original documents 0 facedown on a transparent platen 11. An exposure system, indicated generally by reference numeral 12, includes a lamp 13 which illuminates each document 0 positioned on the platen 11 and the light rays reflected from the document 0 are transmitted through a lens system 15. The lens system 15 focuses the light image of the document 0 onto the charged portion of the photoconductive surface of the belt 6 to selectively dissipate the charge thereof in image configuration.This records an electrostatic latent image on the photoconductive surface which corresponds to the informational areas contained within the original document.

Thereafter, the belt 6 advances the electrostatic latent image recorded on the photoconductive surface to development station C. The platen 11 is movably mounted and arranged to move in the direction of arrows 16 to adjustthe magnification of the original document being reproduced. The lens system 15 moves in synchronism therewith so asto focus the imaging light rays of original document 0 onto the charged portion of the photoconductive surface of the belt 6.

A document handling unit 10 sequentially feeds document sheets from a stack placed by the operator in a normally forward collated order in a document stacking and holding tray. The document sheets are fed in seriatim from the holding tray to the platen 11 and the document handling unit recirculates document sheets back to the stack supported on the tray.

Preferably, the document handling unit is adapted to serially sequentially feed the documents, which may be of various sizes and weights of paper or plastic containing information to be copied. The size of the original document disposed in the holding tray and the size of the copy sheet are measured. Preferably, magnification of the imaging system is adjustable to insure that information contained on the original document is reproduced within the space of the copy sheet.

A plurality of sheet transports 20,21,22,23,24,25, sheet guides 26 and 27 and a decurler 28 cooperate to form a paper path along which the copy sheets being processed pass from either a main paper supply tray 30, or an auxiliary paper sup ~ tray 31, or a duplex paper supply tray 32 through the machine 5 to either output tray 33 or discharge path 34. The transports 20,21, 22, 23, 24, may be driven by a common motor (not shown) with specific gear drives or be provided with their own individual drive system under coordinated action. Suitable sheet sensors designated here by the numeral 35, are provided at the output of each of the paper trays 30, 31 and the duplex tray 32 to detect feeding of a sheet therefrom and sheet monitoring.

With continued reference to Figure 1, at development station C, a pair of magnetic brush developer rollers, indicated generally by the reference numeral 36 and 37, advance developer material into contact with the electrostatic latent image. The latent image attracts toner particles from the carrier granules of the developer material to form a toner powder image on the photoconductive surface of the belt 6.

After the electrostatic latent image recorded on the photoconductive surface of the belt is developed, the belt 6 advances the toner powder image to transfer station D whereat a copy sheet is moved into transfer relation with the toner powder image. The transfer station D includes a corona generating device 38 which sprays ions onto the backside of the copy sheet, thus attracting the toner powder image from the photoconductive surface of the belt 6 to the sheet. After transfer, the pre4user transport 23 advances the sheet to the fusing station E.

The fusing station E includes a fuser assembly, indicated generally by the reference numeral 40, which permanently affixes the transferred powder image to the copy sheet. Preferably, the fuser assembly 40 includes a heated fuser roller 41 and a backup roller 42. The sheet passes between the fuser roller and the backup roller with the powder image contacting the fuser roller 42. In this manner, the powder image is permanently affixed to the sheet.

After fusing, the decurler 28 transports the sheets to the transport 24 which directs the same to a gate 43 which functions as an inverter selector. Depending upon the positon of the gate 43, the copy sheets will either be deflected into a sheet inverter 44 or bypass the sheet inverter and be fed directly to a second decision gate 45. Thus, copy sheets which bypass the inverter 44 are turned 90" in the sheet path before reaching the gate 45 which directs the sheets into a faceup orientation so that the imaged side, which has been transferred and fused, is faceup. If the inverter path 44 is selected, the opposite is true, i.e. the last printed face is facedown.

The second decision gate 45 deflects the sheet directly into the output tray 33 or deflects the sheet into a transport path which carries the sheetto a third decision gate 46. The gate 46 either passes the sheets directly on without inversion to the discharge path 34 or routes the sheets into a duplex inverter roll transport 47.

The transport 47 inverts and stacks the sheets to beduplexed in the duplex tray 32 when the gate 46 so directs. The duplex tray 32 provides intermediate or buffer storage for those sheets which have been printed on one side and on which an image will be subsequently printed on the side opposed thereto, i.e. the copy sheets being duplexed. Due to the sheet inverting action of the transport 47, the buffer set sheets are stacked in the duplex tray 32 facedown in the order in which the sheets have been copied.

In order to complete duplex copying, the previously simplexed sheets in the tray 32 are fed seriatim by a bottom feeder 48 back to the transfer station D for transferofthetoner powder image to the opposed side of the sheet. The transports 20,21,22 advance the sheet along a path which produces an inversion thereof. However, inasmuch as the bottommost sheet is fed from the duplex tray 32, the unprinted or clean side of the copy sheet is positioned in contact with the belt 6 at the transfer station D so that the toner powder image thereon is transferred thereto.

The duplex sheets are then fed through the same path as the previously simplexed sheets to be stacked in the tray 33 for subsequent removal by the printing machine operator.

A suitable machine clock pulse generator 50, which is drivingly coupled to the output shaft of a main drive motor 52, generates a succession of clock pulses whenever the drive motor 52 is energized.

The motor 52 may be connected to each of the transports 20, 21, 22, 23, 24, 47 and the drive for the belt 6 by way of suitable gear means to insure coordinated sheet movement and copy processing.

As will be understood, to enhance copy throughput, several copy sheets may be in process at various locations along the paper path of any one time. To accommodate this and permit individual copies to be tracked and processed in the particular manner desired, timing control over the copy processing functions is divided into pitches, each pitch being further subdivided into a number of machine clock pulses. For example, the paper path may be separated into eleven pitches, one pitch for each copy sheet, with each pitch being composed of approximately 850 machine clock pulses.

Pitch reset signals, which serve in effect to determine the length of the pitch and the number of machine clock pulses within the pitch, are derived from the copy sheet registration finger 53. For this purpose, a switch 54 is disposed adjacent the registration finger 53. As a result, each revolution of the finger 53 trips the switch 54 to output a rest pulse. The output of machine clock pulses by the generator 50 are input through the central processing master for the machine processing control while the pitch reset signals generated by the switch 54 are input directly to a paper handling logic system.

To enable the user or operator of the repoduction machine 5 to control the machine and program the copy run desired, a suitable operator control panel 60 is provided at some convenient location on the machine 5. The copy run instuctions programmed by the control panel 60 are input to the central processing master where a copy information byte for each copy to be made is generated. Further descriptions of the control system for the machine 5 is not necessary for understanding and utilizing the present invention. A complete description of the control system is found in U.S. patent application Serial No.

(D/82147) filed concurrently herewith by the common assignee and which is incorporated by reference.

Referring particularly to Figures 2 and 3 of the drawings, the inverter/reverser 44 includes a chute 65 comprising paper guides 66, 67 made from wire strands spaced apart in parallel and extending in width to a dimension approximately equal to the length of the sheet of paper. The wire guides 66, 67 are spaced one from another a sufficient distance to permit sheets to be driven into and out of the chute 65 without constraints. As shown in Figure 2, the paper guides 66, 67 are curved at their upper ends, and their orientation, starting from a generally horizontal entry position for sheets entering the chute, is such as to terminate in a vertical plane.

The chute 65 includes at its upper entry end the conventional tri-roller transport means for inverters comprising a driven central roller 70 and two idler rollers 71,72 on either side of the roller 70 to be driven thereby. Sheets enter the chute 65 with a side edge or width orientation being conveyed therein by the roller pair 70,71 and being driven out of the chute by the roller pair 70,72.

Spaced between the wire strands comprising the paper guides 66,67, as shown in Figure 2, is a pair of resilient stop members 74, 75. The members 74, 75 extend within the space between the guides 66, 67 and are arranged to intercept the leading edge of the copy sheets entering the chute 65 as the leading edge is being driven downwardly by the roller pair 70,71, The members 74,75 are spaced apart relative to one another a distance shorter than the smallest sheet that the inverter 44 is conditioned to handle so that at all times every sheet entering and leaving the inverter contacts both of the members 74,75. The members 74, 75 are formed as ring-shaped from flexible polyurethane foam having a light spring rate so that the members do not damage light paper and is compliant enough to accept a large mass range.

Recovery of the foam, ring-shaped members to its circular shape is used to drive a sheet into the nip of the roller pair 70,72 after the now leading edge of the sheet is carried to the nip by the roller 70.

Adjacent the lower end of the chute 65 is a yoke element 77 which is positioned horizontally adjacent the wire guide 67 and extends across the width of the chute 65 below the members 74,75. Each of the members 74, 75 is fastened to one end of the yoke element 77 by means of spring snaps 78 which secure the member to a bent tab 79 formed from the material of the yoke 77 and extending through both of the wire guides 66,67. The yoke member 77 is secured to a timing belt 80 which is entrained around an upper driven roller 81 and a lower drive roller 82.

The belt 80 is oriented vertically and has a working run of approximately 127 mm to which the element 77 is attached in order to provide a range of movement of the members 74, 75 for approximately 89 mm.

The adjustable range of movementforthe members 74, 75 is approximately 89 mm in order to permit the accommodation of the international sheet sizes designated as B4 to B5. B4 sheets are nominally 182 mm in width, while the B4 width size sheets are nominally 257 mm. Within this range and contemplated by the present invention are the raising and lowering positioning of the members 74, 75 for standard U.S. sheet sizes, that is, 216 mm.

Another international sheet size is designated as A4 paper having a width of 210 mm. The present arrangement is capable of handling sheet widths as previously stated from 182 mm to 257 mm. It will be understood that other sizes and ranges of paper widths and corresponding range of movements placed upon the members 74,75 may be provided.

The yoke member 77 is arranged to be moved vertically in either direction by means of the timing belt 80. The rollers 81, 82 are arranged for rotation in a frame 90 secured to the frame structure of the machine 5. The frame 90 is generally rectangular in configuration and includes two side rails 91,92 which are vertically oriented and positioned parallel to the lower straight portions of the wire guides 66, 67. Each of the side rails 91, 92 are formed with elongated slots 93,94 respectively. Slideable within each of these slots is a guide pin 95,96 respectively secured to the yoke 77 and which serve to guide the member 77 during its vertical movement in either direction.

The lower drive roller 82 is secured to a shaft 98 suitably journaled in the rail members 91,92 of the frame 90. The shaft 98 is connected to a reversible motor 100 for selectively driving the adjusting member74,75 to any of its vertically oriented positions within the chute 65.

As previously stated, the present invention provides adjustment of stop member 74, 75 for sheets in the inverter 44 in accordance with width sizes of copy sheets placed in the machine 5 for duplex purposes. This adjustment may be made in accordance with known sheet sizes so that specific fixed adjustments can be made to the members 74, 75 which may be positioned for any of a multitude or an infinite number of positioning placements. It is preferred that known fixed widths of copy sheets be utilized to control placement of the stop members and that suitable mechanical adjustment means be incorporated in the sheet supply trays to accommodate changes in standard sheet sizes.

Energization of the positioning motor 100 in either directional rotation to effect corresponding movement ofthe yoke 77 in either direction is under control of switches (not shown) placed relative to the sheet supply stacks 30, 31 and actuated by the width guide plates normally associated with such sheet supply trays. Copiers and duplicating machines in commerical use normally have a copy sheet supply trays with adjustable width guide plates which the operator positions in accordance with the size of the copy sheets to be utilized in the copier/duplicator.

With the use of adjustment positions, the guide plates are provided with fixed stops for ease of operation and control switches are associated with the width guide plates to effect energization of the positioning motor 100 in accordance with the width dimension of the copy sheets.

As an example, if the B4 size paper is to be utilized, the width guide plates will be moved so as to provide 257 mm of space therebetween to accom modate the 84 size paper. When the width guide plates are so moved, a switch positioned in response thereto serves two produce energization the positioning motor 100 to drive the yoke 77 downwardly to its lowermost position in the inverter thereby placing the member 74,75 in position so that when the 84 size sheets are fed into the chute 65, with the width leading edges thereof against the members 74,75, are in position so as to be fed out of the chute by the rollers 70,72. As another example, the width guide plates for the trays 30,31 may be moved closertogetherto accommodate B5 paper having a width of 182 mm.Another switch may be acutated when the width guide plates are moved to accom modate this size paper to actuate the positioning motor 100 to a forward direction to bring the members 74,75 closer to the rollers 70,72.

With these extremes of paper widths and move ment of the members 74, 75 relative to the feed out rollers 70,72, any other size of sheets may be used between this range of movement of the members and is available merely by utilizing additional switch es in the paper supply trays 30, 31 to be actuated by the width guide plates which will be moved to accommodate any particular size paper.

Since the inverter/reverser 44 will be used primari ly for a duplex operation to produce copy sheets having information on both sides, it is envisioned that the energization of the positioning motor 100 will occurwhen the machine has been programmed for the duplex operation. This may be accomplished by a suitable button on the console 60 by a button switch labeled "Duplex" and which conditions the machine 5 for duplex operation. Actuation of this button is combined with the actuation of the switches associated with the sheet supply trays 30, 31, as aforesaid, so that two inputs are necessary in order to accomplish energization in either direction of the positioning motor 100, that is, duplex operation and copy sheet size. In those situations wherein the duplex mode of operation is not to be utilized, but reversal of copy sheet orientation is desired, another operator controlled switch may be invoked to provide the needed signal which was accomplished with the "Duplex" button switch.

Claims (6)

1. A sheet inverter mechanism for inverting sheets including a receptacle for receiving the sheets and arresting movement thereof, means for feeding the sheets out of the receptacle, stop means associated with the receptacle to limit the extent of movement of the sheets into the receptacle, adjusting means for movably mounting the stop means for adjusting the extent to which sheets enter the receptacle, drive means associated with said adjusting means for moving the stop means in order to lengthen or shorten the working range of the receptacle, and control means connected to said drive means for automatically activating the latter in accordance with a sensed dimension of the sheets.

2. The mechanism of claim 1 wherein the stop means is formed as a circular ring against which the copy sheets are driven.

3. The mechanism of claim 2 wherein the stop means is made of resilient material being compliant to resume its circular shape.

4. A reproduction machine capable of duplex copying and including a sheet inverter mechanism for inverting sheets having an image on one side copied thereon prior to being transported to a duplex tray wherein the sheet inverter mechanism is in accordance with any one of claims 1 to 3.

5. The reproduction machine of claim 4 wherein said control means includes means operatively connected to a supply source for the sheets and to a pre-selected mode of operation for the machine.

6. A sheet inverter mechanism substantially as hereinbefore described with reference to the accompanying drawings.