DE2857189C2 - Document input device - Google Patents

Description

a) a first, from the storage container to the exposure station leading, non-inverting part of the track,

b) a second web part, whereby each sheet is turned so that its two sides can be presented to the exposure station for the purpose of copying, and

c) a third part of the web, which leads from the exposure station to the storage container and at the same time turns every bow,

characterized in that the first and third track parts (61 and 73, respectively) represent the storage container (31) and the exposure station (14) directly connect "! And that the second track part (57) runs at least partially with either the first or the third track part (61 or 73).

2. Document input device according to claim 1, characterized in that a sheet template part (33) is provided which transports the sheets (S ) away from the bottom of the storage container (31) one after the other.

3. Document input device according to claim 1 and 2, characterized in that a Sheet return part (35) is provided, which the Sheet removed from the exposure station.

4. Document input device according to one of claims 1 to 3, characterized in that the storage container (31) is arranged above and at a distance from the exposure station (14) is

5. Document input device according to one or more of the preceding claims, characterized characterized in that the reservoir (31) has an inclined bottom (37) and side guides having.

6. Document input device according to one or more of the preceding claims, characterized characterized in that a detector (39) is provided which detects when each time the set of Original sheet was copied.

7. Document input device according to one or more of the preceding claims, characterized characterized in that a sheet template section (33) is provided which has an oscillating vacuum pick-up device (41), a drive gap and a sheet deflector (47).

8. Document input device according to claim 7, characterized by a worm-like Shell (49) and two drive rollers (51 and 53).

9. Document input device according to claim 7 and 8, characterized by a guide part (54) and roles (63.65).

10. Document input device according to one or more of the preceding claims, characterized by an alignment stop (69) adjacent to the exposure station (14).

11. Document input device according to one or more of the preceding claims, characterized by a sheet reversing path (73) and two drive rollers (75,79).

12. Document input device according to one or more of the preceding claims, characterized characterized in that, with the elimination of the screw jacket (49), the reversing path (57) twice is used.

13. Document input device according to one or more of the preceding claims, characterized characterized in that the operation is controlled by a logic and control unit (9) he follows

The invention relates to a document input device for recirculating a stack of Duplex document sheets along a closed loop path from a storage container via an exposure station back to the reservoir of a copier to generate a desired number of copies with the sheets stacked in the supply bin in a predetermined order and orientation are, the input device has sheet input and guide means to feed the sheet, each individually to effect, and the loop track has the following track parts:

a) A first, not invirtierekd <. * n track part, leading from the storage container to the exposure station,

b) a second web part, whereby each sheet is turned so that its two sides on the Exposure station can be presented for the purpose of copying, and

c) a third part of the web, which leads from the exposure station to the storage container and at the same time each Bow turns.

Document input devices for copiers, like the copiers themselves, are already known. It is desirable that copiers be capable of duplex copying of both duplex originals from simplex originals. The US-PS 39 47 270 already describes a copier which is able to do so. This is the so-called »single pass« solution, in which images on both sides of a copy sheet during a single pass of the copy sheet through the copier be fixed. In the electrophotographic apparatus described in this patent sequentially two images of an original are formed on an endless photoconductor. The images are formed then developed, and the first developed image is transferred to the first side of a sheet of copy. Then If the copy sheet is separated from the photoconductor, it runs through a fusing device to form the first transfer image to melt on the copy sheet, whereupon the copy sheet is reversed and the opposite side of the copy sheet in contact

is brought to the photoconductor with the second developed image. Then the second picture becomes the second Transferring the side of the copy sheet, the copy sheet is separated from the photoconductor, and the second image is melted by means of a second melting device. Then the copy sheet becomes one Copy pick-up transported Although it is possible with the known device to produce duplex copies, so this device has a number of disadvantages. For example, the first picture is before flipping of the copy sheet is fixed, which requires the use of two fusing devices Increased costs. Performance and waste heat are the result.

Another duplex process uses the so-called "double pass", in which an intermediate container is used, which collects the copy sheets after these images are on a first page have received, whereupon the collected sheets are returned sequentially through the copier to take the pictures on the second page. Such an electrophotographic apparatus is described in the following section: February 1976 - Research Disclosure issue. Volume 142. No. 14 237, page 38 (published by Industrial Opportunities Limited, Homewell Kavant, Hampshire PO9, IEF, England, and in US patent 37 19 266).

Although the double pass in certain commercially available electrophotographic devices is used, it also has several disadvantages. As the first pages of all copy sheets before developing the second sides of the copy sheet is a duplex copy available for review only after all first pages and a set of second pages are developed. In addition, the relatively long paper webs required for the two-fold Passing a sheet of copy through the entire electrophotographic apparatus required Possibility of paper clogging or other copy handling complications, what about In addition, the efficiency and productivity of the copier are also decreased. For example, it can be when copying of a two- or three-page document take longer for the first sheet of copies, for the second Go back through the copying process as it takes for all other copy sheets to get the to run through the copying process for the first time.

Further, in the copying apparatus using either the single pass or the double pass method the images / with the first and second sides of a copy sheet in two different Melting operations merged. Thus, an image of each sheet needs to be fused twice while the other image only goes through a melting process once. This results in a potential problem in that the physical parameters of the copy sheet, e.g. Moisture content, can be changed, resulting in images of different quality on opposite sides Pages of a single sheet or sheet. Further, a toner is required which has a large size Has adaptability in terms of melting time and temperature.

DE-OS 27 23 458 relates to a device for generating collated copies of two-sided Originals. This publication is an older right.

The present invention is based on the object of providing a document input device as described in the opening paragraph mentioned type in such a way that repeatedly automatically collated duplex copies can be produced are.

To solve this problem, the invention provides that the first and third track parts the storage container and connect the exposure station directly to one another, and that the second web part at least partially ίο runs with either the first or the third part of the track

Preferred embodiments of the invention emerge from the subclaims.

Other advantages. Objects, details and features of the invention emerge in particular from the claims as well as from the description of exemplary embodiments with reference to the drawing; in the drawing shows

F i g. 1 is a schematic representation of a copier according to the invention with duplex copying capability,

F i g. 2 a schematic representation of the documents in ^<T EbevQrrichtun ^(T der F i °. 1

F i g. 3 is a schematic view of the document path in the duplex-aüi-dupiex mode of operation of the document input device;

F i g. Figure 4 is a schematic view of the copy path in the dupiex-on-duplex or simplex-on-simplex mode of operation of the copy processing section.
It is now particularly to the F i g. 1 and 2, where an electrophotographic copier 100 is shown schematically and has an image processing section 3, a document input device 5, a copy processing section 7 and a logic and control unit 9 of original document sheets, typically as an imagewise distribution of electroscopic marking particles. The document input device 5 supplies the original sheets to the image processing section 3 to generate visual representations, while the copy processing section 7, in synchronization with the input section 5, provides the copy sheets to the image processing section 3 to receive visual representations which constitute the final copies. The logic and control unit 9 coordinates the operation of the three sections as required.
The document input device (FIGS. 1, 3, 4) will now be described first. The document input device 5 has a storage bin 31, a sheet template 33 and a sheet return part 35. The bin 31 is used to receive a set of original document sheets 5, face up in the normal page order, so the sheets 5, one after the other to deliver the last sheet first from the bottom of the document set, the sheets San on top of the document set being received again, each sheet on top of the previously delivered sheet. The sheet original part 33 removes the sheets S one after the other from the bottom of the container 31, presents a removed sheet with one end face in contact with the platen 14 for copying, and in the duplex-on-duplex mode, places the sheet again with it the other end face in contact with the plate. The sheet return part 35 removes the sheet from the plate fBelichtunessta-

tion) 14 after one or both faces are copied and brings the sheet to the top of the container 31 in the original order of the document set.

The structural features of the document input device 5 will now be dealt with specifically, in particular to FIG. 3, according to which the container 31 is arranged above and at a distance from the plate 14 where it is easily accessible to receive and carry the set of original document sheets 5. The container 31, constructed in the usual way, has an inclined base 37 to assist in aligning the document sheets S on a front wall 38, with lateral guides and pushing elements (not shown) being provided, as well as a "set completed" detector 39 for determining, without counting, when (each time) the set of original sheet S was copied.

The sheet template section 33 has a first, second and third part. The first part is through an oscillating vacuum pick-up device 41, a drive gap formed between ring 43 and a support roller 45 and a sheet deflector 47 is formed. A second part has a helical jacket 49 and two drive rollers 51 and 53 which define a non-reversing sheet path (web) 61. A third part has guide part 54 and rollers 63 and 65, the first and second sheet reversing tracks 55 and 65 respectively. 57 define.

The first part of the sheet template section 33 is removed the sheets 5 from an exit 59, located at one end of the container bottom 37, and directs a distant one Arch in a selected inverting or non-inverting path 55 or 61, depending from the position of the deflector 47. The sheets are first removed by vacuum pick-up device 41, soft an Er.de of the bow pulls out of the exit 59, whereupon the sheet is driven into the selected path through the drive nip. at the duplex-on-duplex mode of operation of the document input device the sheets are guided by the deflector 47 into the non-inverting sheet path 61. In the simplex-on-simplex or simplex-on-duplex mode of operation the sheets are moved through the deflector 47 into the inverting or reversing sheet path 55 and passed onto the plate 14 in a manner as described in DE-OS 25 50 985.

As mentioned above, the duplex-on-duplex mode of operation leads the second part of the sheet template section 33 a removed sheet to the plate 14 without Reversal of the arch or, in other words, with the lower face (even-numbered side) of the arch in contact with the plate 14. In one sense, as mentioned above, this arrangement defines a non-inverting one Arch path 61, which leads from the container 31 to the plate 14 ss. In another sense, however, it is a shutdown device which makes the reversing arc path 55 ineffective for deflecting the sheets Im In operation, a sheet entering web 61 from deflector 47 is rolled into helical shell 49 namely under the force of movement of the rollers 51 and 53 until the rear end of the sheet from the deflector or deflector is released. The rollers 51 and 53 are then reversed around the sheet from the jacket around the Driving guide parts 54 around and with the support of roller 63 onto plate 14.

The third part of the sheet template section 33, which only works in the Duplcx-auf-Dtiplcx-Betricbsari, has been removed an arc from the plate 14 after the first face thereof is copied and inverts the arc or flip it over to copy its other face. This is through the reversal path 57 and the Drive rollers 63 and 65 reached, which drive the sheet 360 ° back onto the plate 14.

The plate 14 itself forms a sheet registration and exposure station including rollers 67 and one Alignment stop 69. Upon entering the exposure station, a document sheet is fed through rollers 67 driven into an aligned position with respect to the stop 69. After the first face of the arch is copied, the rollers 67 are reversed, once to drive the sheet into the reversing path 57, and again to realign the sheet to copy the second face. If then the second end face is copied, the stop 69 is removed by an electromagnet 71 and the rollers 67 drive the sheet towards the third part of the input device.

The sheet return part 35 has a sheet reversing path 73 and two drive rollers 75 and 79 to the Return the document sheet to the top of the set from which this sheet was originally removed had been.

The non-reversing path 61 retains, as described above, the original orientation of the sheet end faces when moving from the container 31 to the Plate 14 in the sense that the sheet, although it can be rolled in the screw jacket 49, never completely flipped over. However, those skilled in the art will recognize that an even number of arc reversals would also present the sheet of the plate with the same side down for copying. Accordingly, the screw shell 49 could be eliminated and the reversing path 57 could then be duplicated used (i.e. an even number of times before copying). This would become the original document sheet surfaces in the same order as the structure described above. The inverting orbits could have a similar relationship 55, 57 and 73 have one or a further odd number of inversions or reversals and still serve the purpose described. The document input device is sometimes called a circulating or recirculating input device denotes because the sheets 5 are in the input device repeatedly from the container 31 to the exposure plate 14 and back to the container in a manner move that a closed loop or a kr .s-shaped Simulate path. It is a collating input device because it is capable of is to enter the sheets in the correct order to make collated copies without a sorting device to create. This aspect of the input device will become more apparent from the following description. It The input device according to the invention is also a duplex input device in FIG in the sense that it is capable of inputting original duplex document sheets in a manner conducive to generation of duplex copies

The image processing section 3 (see FIG. 1) sees the original document sheets 5 arranged on the transparent plate 14 by means of the input section 5 and pre-creates visual representations on an image transfer member such as a photoconductor 15 carried on a drum 16 for movement in a cylindrical or closed path.

past a number of processing stations. As the processing stations from known Constructions can be selected here, a limitation to a few details as follows take place.

At a charging station 17, the photoconductive surface of the photoconductor 15 is made sensitive by receiving a uniform electrostatic charge. At an exposure station 19, an image of an original document sheet 5 on the platen 14 is projected onto the photoconductor 15. At a developer station 21, developer powder including electrostatic toner particles having an electrostatic charge opposite to that of the latent electrostatic image is brushed over the photoconductive surface of the photoconductor 15, with the result that toner particles adhere to the latent electrostatic image and form a visible toner image which is a mirror image of the original document sheet S. At a copy processing station 7, first and second non-fixed toner images are electrostatically transferred from the photoconductor 15 to the opposite side of a copy sheet 5 'in the duplex mode, before each of the images is fixed on the sheet 5'. Post-development erase stations 25 and 26 remove any original charge remaining on photoconductor 15 by the application of light and a corona discharge, respectively. At a cleaning station 27, the photoconductive surface of the photoconductor 15 is finally cleaned of any residual toner particles that verb '^; are flat after the toner images are transferred.

The copy processing section 7 has the following: one or more supply containers 81 for receiving and sequentially inputting copy sheets S 'into an alignment device 28, first and second transfer stations 83 and 84 including transfer and delamination coronas 85, 86, 87 and 88, a sheet reversing device 89, a vacuum stripping roller 91 and an exit tray 93. The supply tray 8t can be constructed in many respects similar to the tray 31 of the document input device, including a support base 95 and a pick-up device 97 for pulling one copy sheet at a time from a stack of such sheets S ' , and in order to direct the drawn out sheets towards the photoconductor 15, specifically along suitable guide channels (not shown).

In the duplex mode of operation, a copy sheet 5 'is transferred from the supply container 81 to the alignment device 28, which momentarily interrupts the movement of the copy sheet to prevent it from arriving at the align first transfer station 83 in alignment with the arrival of the first image zone on photoconductor 15, whereupon the sheet in contact with the photoconductor at the same relative speed as the photoconductor is routed.

At the first transfer station 83, a DC transfer corona charger 85 applies a charge to one side of the copy sheet S 'adjacent the charger. In this way, the copy sheet 5 'adheres electrostatically to the photoconductor 15 and transfers the first toner image formed by the above-described image processing section 3 from the photoconductor to the first side of the copy sheet 5'. The delamination corona 86, an AC corona charger, then eliminates the electrostatic forces which cause the copy sheet S ' to adhere to the photoconductor 15 so as to facilitate the removal of that copy sheet from the photoconductor.

The sheet reversing device 89 has a relatively short vacuum transport device 101 and a stripping and deflecting finger 103 in order to remove the copy sheet 5 'from the photoconductor 15 and to arrange the opposite end face opposite it. The vacuum transport device 101 is connected to a suitable source (not shown) for maintaining a vacuum in the end roller 107 and a space 109, which vacuum communicates with the copy sheet S ' through perforations in a reversible belt 112. If If the copy sheet S ' emerges from the first delamination corona 86, it is drawn away from the photoconductor 15 by the vacuum in roller 107 and onto the belt 112, which first runs in a clockwise direction. The stripping and deflecting finger 103 can also have a supporting effect, but preferably only touches the end face of the copy sheet 5 '. that has not yet received a picture because the picture is not yet fixed and could easily be smeared. When the copy sheet 5 'is completely removed from the photoconductor 15 and its rear end has come free from the stripping and deflecting finger 103, the direction of the belt 112 is reversed in order to bring the copy sheet S' back to the photoconductor 15 along the path 113, which is caused by the stripping - and rotating finger 103 is defined in such a way that the second non-image-bearing side of the copy sheet 5 'is in alignment with the second image area on the photoconductor. As the copy sheet S 'is separated from and brought back into contact with the photoconductor 15, the belt 112 is driven at a speed appropriate to the speed of the photoconductor and the distance between the first and second unfixed toner images which are on the copy sheet 5'. should be transmitted to correspond on the photoconductor. Normally, the spacing between the first and second images on photoconductor 15 can be kept to a minimum because of the relative location of sheet reverser 89 with respect to transfer stations 83 and 84. In addition, the spacing between toner images can be kept small by some means of moving the edge of 5 '(the trailing edge of the first image or the leading edge of the second image) in a path that closely follows the path of the photoconductor. Such means may be mechanical, pneumatic or electrostatic devices which deflect the edge of the copy sheet S' while this is free from the photoconductor 15 and while the belt 112 is running in reverse, the manner in which the copy sheet S 'is positioned for the re-contact with the photoconductor and the movement of the belt 112 is reduced. It should be noted that during the reversal of the copy sheet S ' the first toner image transferred to the first side thereof remains unfixed and is not destroyed during the reversal since the vacuum belt 112 is only in contact with the second non-image side of the sheet 5 'comes Accordingly, no fuser is required to fix the first toner image with the copy sheet S' before the reversal of the copy sheet and before the transfer of the second toner image.

The second transfer station 84 is designed essentially identically to the first transfer station 83 and serves to transfer the second toner image to the second, non-image-bearing side of the copy sheet 5 ', which then touches the photoconductor whereupon

the delamination corona charger 88 removes the copy sheet S 'for the second removal Prepared by the photoconductor This transfer and delamination is not fused without disturbing the Reached toner image on the first face of the copy sheet 5 '.

After the two unfixed toner ^{images have been transferred to J} .en copy sheet 5 ', vacuum stripping roller 91 pulls the copy sheet off photoconductor 15 and guides the copy sheet S' through a fuser 29, which has oppositely arranged rollers 29a and 296 As toner particles forming copy sheet S ' are heat-fusible, both rollers 29a and 296 are heated to heat fuse the two unfixed toner images onto opposite sides of the copy sheet 5'. If the toner particles can be melted by pressure, the rollers 29a and 296 need not be heatable and the fixing on the sheet 5 'is effected solely by pressure. From the melting device 29 the copy sheet 5' is transported to an output container 93, where each Copy sheet is delivered to the top of the previously delivered sheet, with the last transferred image facing up. Of course, other stripping devices could be used in place of roller 91. In the case of a copier with a flexible belt, for example, the belt can be guided to pass through a relatively sharp shape, which separates the copy sheet from the belt

The duplex process just described is referred to as a single pass duplex process because none Intermediate container is required Rather, the copy sheets run directly from a supply container an output tray or copy-handling accessories such as a finisher, not shown, with only a single pass through a melting device

In the simplex-to-simplex mode of operation, the second transfer station 84 and the document inverting device 89 are not in operation. The toner images on the photoconductor 15 are transferred to the copy sheet S ' at the first transfer station 83, removed from the photoconductor by the stripping roller 91 and transported to the fuser 29

Let us now turn to the overall operation of the copier received. A document or other original from a set of individual sheets is called a sheet after arc from the container 31 to the exposure plate 14 and back to the container 31 is circulated and recirculated In the example of a six-sided duplex original, the sheet defining pages 5 and 6 becomes first circulates to copy page 6 and then page 5. This is followed by the one defining pages 4 and 3 Arc and finally the arc defining pages 2 and 1. The arcs are sequentially on page 6 through page 1 for the purpose of copying and each page is presented only once during each corresponding Circulation exposed to collate copies without a sorter. Multiple copies will be generated by circulating and recirculating the sheets as often as copies are desired.

If the pages are presented sequentially for the purpose of copying, then a sequence of the presented Pages representing images generated in image zones of the photoconductor, successively in the same order as the submitted pages, d. H. Page 6, Page 5, Page 4, Page 3. Page 2 and Page 1. The an The development station 21 made visible images are by twisting the photoconductor in a Position for the subsequent transfer to alternate pages of copy sheet 5 'brought, and

at first and second transfer stations 83 and 84. The even-numbered sides would be on the first

Station 83 and the odd-numbered pages would be on

the second transmission station 84 transmitted.

For every circulation or recirculation of a document

mentenbogens such a bow twice for one Exposure presented and two images are generated. Likewise, a copy sheet 5 'becomes the processing station 3, first with one side and then with the other side for recording

is of the two pictures. The first copy sheet receives on one side an image representing page 6 and then on the other side page 5. The next sheet of copies receives pages 4 and 3 and the following copy sheet receives pages 2 and i. It can of course additional copies are made in the same order and on top of the previously made copies be placed in the output bin.

When making collated simplex copies of simplex originals, the input device could work in the manner described in the above DE-OS. The same applies to the production of Duplex copies from simplex originals, as far as the input device is concerned, but the copy processing section the two end faces of the Copy sheet S 'would be presented to the photoconductor to receive toner images in the manner described. In FIG. 1 is a logic and control unit (LCU) 9 for carrying out the operating modes described above The function of this unit is generally to monitor the activities of the image processing section 3 of the input section 5 and the copy processing section 7 to coordinate. In the special embodiment a minicomputer is used. Programming a number of commercially available Minicomputers or microprocessors are known to those skilled in the art enable the programmer with his specialist knowledge to develop a corresponding program for the Mini computer to write. The specifics of such a program would of course depend on the architecture the selected computer.

The LCU 9 consists of a temporary data memory 123, a central processing unit 125, a timing control unit 127 and a storage program control device 129. Data input and output are sequentially performed by program control Input data (INPUT) are fed to the central processing unit (CPU) 125 either through an input signal buffer coupled to a multiplexer (INPUT DATA MULTIPLEXER) 133 (INPUT SIGNAL BUFFERS) 131 or via an interrupt signal processor (INTERRUPT SIGNAL PROCESSING) 134, which is coupled to an incremental encoder 114. The encoder 114 is connected to the Drive means connected to the photoconductor drum 16 to provide information indicating the position of the itself moving photoconductor related to the positions of the fixed processing stations

The input and output signals are shown in FIG. 1

dutch reference numerals 139-154 represent the following Control lines are referred to as:

139 leads to the alignment stop 69 of the document

! ^ input device for controlling the two stop positions (raised and lowered or present and removed);

140 leads to the “sentence completed detector 39 for the purpose of counting the number of copies completed;

141 leads to the sheet drive rollers 67 for fixing of their direction of rotation;

142 leads to the sheet deflector 47 of the document input device to control their two positions (reverse and non-reverse);

143 leads to the drive rollers 51 and 53 for determining their directions of rotation;

144 leads * to the lighting source 156 for control the lighting intensity and scan control;

145 leads to the image projector 10 for controlling the optical scanning synchronously with the illumination source 156;

146 leads to the primary charger 17 for maintaining a uniform charge;

147 leads to development station 21 for bias control;

"C" and "F" lead to the incremental encoder 114 for recording timing signals (counting and image zone signals);

148 leads to copy sheet input roller 97 for introduction copy sheet input from tray 81;

149 leads to the transmission and release coronas 85 and 86 in the first transfer station 83 for transfer control;

150 leads to inverter 89 for determining the direction of movement of belt 112;

151 leads to the transmission and release coronas 87 and 88 in the second transmission station 84 again for transmission control;

152 leads to the Abstreifroüe Si for controlling their wiping effect;

153 leads to the melting station 29 for temperature control;

154 leads to extinguishing and cleaning stations 25 and 26 for controlling their operating intensities.

The output data and control signals are applied to memory latches 135, the input variables for suitable output drivers 137 which are directly coupled to the mentioned conductors, which in turn are connected to the copier workstations. The output signals from the LCU are special Logic level digital signals that are buffered and amplified to generate drive signals for various clutches, Brakes, electromagnets, circuit breakers and numeric displays in the various copier workstations and to be generated in the input device 5 of the copier 10. The processing functions the LCU 9 can be programmed by changing the commands stored in the computer memory.

The program is located in the memory program controller 129, which has a conventional ROM can. The ROM contains the operating program in the form of commands and fixed binary numbers accordingly the numeric constants. These programs are permanently stored in the ROMs and can cannot be changed by the computer operation.

The temporary data memory 123 can be formed by a conventional read / write memory. The read / Write memory or RAM differs from ROM in terms of two properties: 1) Stored data are destroyed when the power is switched off and

s 2) the stored data is easily changed by that one writes new data into the memory.

Under the influence of the logic and control unit 9 the original of the original document sheet 5 and the copy sheet S 'is sent to the image processing section 3

ίο coordinated in such a way that the copies in the above-described Page order can be collated. An exposure is carried out for each original of an original sheet, to provide a visual representation on one face of the sheet, and for each visual If the representation is intended, a copy sheet face is presented to accommodate this representation. Thus, the original and the copy sheet end faces are input on a 1: 1 basis. This is not supposed to mean that there is an equal number of originals and copy sheets, which of course not is the case when making multiple copies, but rather it should be said that on a 1: 1 basis is available for the corresponding with regard to the presentation of the corresponding arch faces on the verai - processing section 3. It is also not necessary that the original and the corresponding copy sheets for must be entered at the same time. In general, the entry of an original sheet is opposite in time the entry of the corresponding copy sheet either forward or backward, and although depending on the design of the copier.

The control and logic unit 9 also keeps track of the copies during their production and directs the document input section 3 and the copy duplex section 7 such that in the duplex-on-duplex mode the The first and second end faces of the copies properly match the first and two faces correspond to the original sheet.

Staggered stacking, stapling and other finishing operations are not shown. If such a Device is used, it can be controlled synchronously with the copier, and preferably by the logic and control unit 9.

The invention provides modes of operation which take into account the usual variations in the originals. A duplex original that ends on the first face or side of the last sheet does not need to be on the empty face to be copied. It is also clear

so that not all possibilities available according to the invention have to be used in every operating mode. Accordingly, the document input device could provide a non-collating mode of operation, in which each side of the plate surface is presented regardless of the number of copies to be made could.

Numerous advantages of the invention are evident. The invention provides an electrophotographic copier before, the efficiently collated duplex or simplex copies in the correct Page order generated from both duplex and simplex originals. In the duplex mode, a first copy completed on both sides before other copies are initiated. This will make the first copy time required decreased. Each copy sheet goes through the fuser only once, and only after the toner images have been recorded on both sides, so that the sheets are in their optimal relative

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Keep moisture in both transfer stations. The total copy path from the initial bin to the eventual exit is thereby reduced to improve copying efficiency, especially for documents with only a few 5 Pages that do not require a sorting device. In addition, a relatively simple, collating, inverting Document input device made possible with just a single container, while the convenience of presenting the document to 10 the input device is retained with the face up

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Claims (1)

Patent claims: 1. Document input device for recirculation of a stack of duplex document sheets along a closed loop path of one Storage container via an exposure station back to the storage container of a copier for production a desired number of copies, with the sheets in the supply bin in a predetermined Order and orientation are stacked, the input device sheet input and guide means has to cause the advance of the sheets, one at a time, and this loop path has the following track parts: