JPH0219958B2 - - Google Patents

Description

[Detailed description of the invention]

[Technical Field] The present invention relates to a double-sided image forming apparatus that forms images on both sides of a sheet-like image carrier. [Background of the Invention] In conventional image forming apparatuses such as copying machines, it has been common practice to form an image only on one side of a single sheet-like image carrier (hereinafter referred to as a copy sheet). However, when storing a large number of copy sheets, the amount is twice as large as that of a book or the like printed on both sides of a single sheet, which poses problems in terms of storage space and weight. From this point of view, devices capable of forming images on both sides of a sheet have been proposed in recent years. One such device first makes a set number of copies on the front side of a sheet, temporarily stores it in an intermediate tray, and then feeds the sheet from the intermediate tray and copies a set number of copies on the back side of the sheet. There are some that copy . In this case, if double feeding of sheets occurs during front side copying, the intermediate tray contains more sheets than the set number, and when back side copying is performed for the set number of times and the copy operation is completed, the front and back sides are copied. Unable to get the set number of sheets. [Objective] The present invention has been made in view of the above points, and its object is to provide a double-sided image forming apparatus that can reliably obtain a set number of recording materials with images formed on both sides. It is in. That is, the present invention provides a first input means for inputting a desired number of times of image formation, a storage means for storing data of the number of times of image formation inputted from the first input means, and a method for recording the image after forming the image on the first surface of the recording material. Image formation in which images are formed on both sides of the recording material by sequentially performing a first step of storing the material in a temporary storage means and a second step of forming an image on the second side of the recording material fed from the storage means. means, a detection means for detecting the presence or absence of a recording material in the storage means, a counting means for performing a counting operation in accordance with an image forming operation executed by the image forming means, and a start signal input by the second input means; In response, the image forming means
The operation is started in the first step, and the image forming operation is performed in the first step until the counting means counts the amount of data stored in the storage means, and when the counting means counts the amount of data stored in the storage means, the image forming operation is started. The image forming operation in the first step is completed in response to the count up signal, and furthermore, after the first step is completed, the image forming means is started in response to the start signal inputted from the second input means. The operation is started in a second step, and the image forming operation is performed in the second step until the counting means counts by the amount of the stored data, and even if the counting means counts by the amount of the stored data, the detection means While it is detected that there is a recording material in the storage means, the image forming operation in the second step is further continued in response to a signal indicating the presence of recording material outputted from the detection means, and the image forming operation in the second step is continued. and control means for terminating the image forming operation in the second step in response to a signal indicating no recording material output from the detection means when the means detects that there is no recording material in the storage means. The present invention provides a double-sided image forming apparatus characterized by the following. DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be explained in detail with reference to the drawings. FIG. 1 is one embodiment of the present invention, and is a sectional view illustrating a copy paper conveyance path of a double-sided copying device. FIG. 2 shows the operating device. [Description of machine operation during single-sided copying] First, the operation of general single-sided copying will be explained. In FIG. 1, an original 1 is placed on a transparent plate 2 of an original table, and an optical system is composed of movable reflecting mirrors 3, 4, a lens 5, and fixed reflecting mirrors 6, 7. That is, the document 1 is moved between the movable reflecting mirror 3 that moves together with the illumination lamp 8 and the movable reflecting mirror 3.
While the optical path length is kept equal by the movable reflecting mirror 4 which moves in the same direction at a moving speed of 1/2 of imaged. The surface of the photosensitive drum 9 consists of a photoconductor with a photoconductive layer covered with a transparent insulating layer, and the photoconductor is first positively charged by a positive charger 11 that is supplied with a high positive voltage from a high voltage power source 10. . Next, when reaching the exposure section 12, the transparent plate 2 of the document table is exposed.
The upper original 1 is illuminated by an illumination lamp 8 and moved by moving reflecting mirrors 3, 4 and lenses 5, and fixed reflecting mirrors 6, 7.
An image is formed on the drum 9 by this. The photosensitive drum receives an AC discharge from an AC discharger 13 to which an AC high voltage is supplied from a high voltage power supply 10 at the same time as the original image is exposed to the photosensitive drum. Next, the entire surface is exposed by the entire surface exposure lamp 14, and an electrostatic latent image is formed on the surface of the photosensitive drum, which enters the developing device 15. Development is performed by powder development using a magnetic sleeve method, and the electrostatic latent image is visualized. Next, copy paper 1
6 is a station from which paper is sent out from the paper feed section, and the relay tray 17 and the first paper feed table 18 of the paper feed section are of the cassette type, and the second paper feed table 19 has an automatic paper lifting device and carries a relatively large number of sheets. It is a deck type that can be loaded. Although the details will be described later, the relay tray 17 is also used as a paper feed stand during double-sided copying. Copy paper 16 fed from one of paper feed sections 17, 18, and 19 is brought into close contact with drum 9.
The transfer charger 20 positively charges the transfer paper using the high voltage power supply 10 and transfers the image on the drum 9 onto the copy paper. After the copy paper has been transferred, it is transferred to the drum 9 at the separating section 21.
The paper is separated from the paper and guided to the fixing section 23 via the transport path 22. The fixing unit 23 includes a fixing roller 24 having a heating source.
A copy paper having a powder image is passed between the rollers that are in pressure contact with each other, and the powder image is fixed on the copy paper by pressure and heat. On the other hand, the remaining toner on the drum is cleaned by the blade 26 pressed against the drum surface, and the next cycle can be repeated again. Fixing part 2
The copy paper 16 that has passed through the paper 3 is sent out to a conveyance path 27. The conveyance path 27 includes a conveyance position (a) to the relay tray 17 (indicated by a solid line) during double-sided copying (described later), a conveyance position (b) to the sorter unit 30, and a conveyance position (c) to the storage tray (both shown by broken lines). The mode can be switched in three stages (shown by Conveyance path 2 to tray 31 side, sorter 30 side or relay tray 17 side
7 is switched. Similarly, the above operations are performed using count key 3.
Enter the desired number of copies using 4 and press the copy start button 3.
This is done automatically by pressing 5. As shown in FIG. 2, a display section is provided to display the set number of copies and the number of copies to be completed. The upper display 61 displays the number of sheets set using the numeric keypad 34. Lower display 6
2 displays the number of copies. For example, if 20 sheets are set using the numeric keypad 34, the upper display 61 will display 0|2|0, and each time each copy is completed, the lower display 62 will change from 0|0|0 to 0|0|1,
It counts as 0|0|2---, and the copy ends when it reaches 0|2|0. This display format is called additive type.
Conversely, a format in which the lower display 62 displays 0|1|9, 0|1|8, ---0|0|0 from the set number of sheets 0|2|0 is called a subtractive type. Although it does not matter whether the display 62 is an addition type or a subtraction type, in this embodiment, the addition type will be explained. Next, the paper jam detection device 36 to 4 in the paper path described above
4 is provided, and the measures to be taken in the event of a paper jam are as follows. () When a paper jam is detected by the detection device 36, 37, or 38, the paper present in the conveyance path after the separator 21 (not including the separation section) is discharged to a designated exit (ex tray, sorter). If paper is present in the transport path 22, it is discharged after undergoing a fixing process. At this time, all other processes (exposure, charging, development, transfer, etc.) are stopped. The ejected copy paper is considered to be a normal copy. Copy paper remaining in the machine will be removed with a jam indication and will not be counted as a completed copy. () When a paper jam is detected by the detection device 39, 43, or 44, the paper existing after the detection device is ejected, and all other process operations are stopped. Instructions for counting finished copies and removing paper jams are the same as in (). In order to realize the above operations, all the drive sources for each function can be controlled independently. Further, the relay tray 17, the first paper feed tray 18, and the second paper feed tray 19 are each provided with detectors 54, 55, and 56 for detecting the presence of copy paper. [Explanation of machine operation during double-sided copying] Next, double-sided copying will be described. In this embodiment, a standard mode is set for each copy mode, and the standard mode is designated without the need to designate a mode when power is turned on to the apparatus. This standard mode is a commonly used copying mode, and in Figure 2, it is "single-sided".
For "double-sided", "single-sided" is used, "tray" is used for exit, and "normal" is used for original density. Even if a mode other than the standard mode is specified, if the copy start is left unoperated for a predetermined period of time without the button 35 being operated, the mode is automatically returned to the standard mode. Through these operations, the machine is always maintained in a state that is convenient for the operator. Now, when the operator presses the duplex button 80 and specifies the duplex mode, the mode becomes the first side copy mode. That is, the lamp PL9 lights up and the first side of the copy paper is displayed, and at the same time the conveyance path 27 moves to position a.
can be switched to As will be described later, when the second side copy starts, the lamp PL10 is similarly turned on to display the second side copy, thereby making it possible for the operator to improve the operability. Similarly, selection buttons 71 to 8 for each copy mode
2 has an operation input function and a light emitting diode above the button.
It has LED1 to LED12, and when selected, the light emitting diode lights up to display the selected mode. Next, select another copy mode, set the number of copies, and copying starts, but when duplexing, relay tray 1
7 cannot be used as a copy paper feed tray for the first side, and paper can be fed only from the first and second paper feed trays 18 and 19. If there is copy paper in the relay tray 17 when copying the first side, it will be detected and the lamp PL11 will light up to display the message "Remove paper from the relay tray" and the operator can remove the paper. Copying will not begin until After copying starts, all copying modes other than the "stop" button 45 are held and cannot be changed. The other processes up to exposure, development, transfer, and fixing are the same as those for single-sided copying. Fixing part 2
The copy paper 16 that has passed through the paper 3 is fed into the relay tray 17 via a conveyance path 27. At this time, the leading edge of the paper conveyed is relay tray 1.
7 (opposite side of the paper feed port), and the rear end is stored toward the paper feed port side. As shown in the figure, the relay tray 17 is configured such that the paper feed port side is lowered compared to the opposite side, and the leading edge of the copy paper is aligned with the paper feed port side due to its own weight, and is fed when the next second side is copied. Paper is becoming easier. When copy sheets corresponding to the set number of copies are stored in the relay tray 17, the first side copying ends. At the same time as this ends, the lamp PL10 lights up to display the second page and prompt the operator to replace the document for the second page, and at the same time, the transport path 27 is switched to the designated exit. At this point, each copy mode suitable for the second side is designated again. However, it is not possible to shift to "single-sided" copy mode. In response to the signal to start copying on the second side, the copy paper in the first paper feed tray is sent out to the conveyance path 46, and, like the first side copying, it goes through the processes of exposure, development, transfer, and fixing, and then is sent out to a designated exit. Make a two-sided copy. At this time, as mentioned above, the copy paper stored in the relay tray 17 after the first side copying has the first side copied on the front side, and the back side is blank, so the second side is
Double-sided copying is automatically done on the back side of blank paper. Then, for all the copy sheets in the relay tray 17, the second
When the surface copying is completed, the lamp PL10 goes out and
The lamp PL9 lights up and the mode shifts to the first side copying mode, in preparation for the next double-sided copying. However, if double-sided copying is not performed even after a predetermined period of time has passed after the second-side copying is completed, the standard mode is returned to, as described above, and the single-sided copying mode is established. It is of course possible to shift to the single-sided mode by pressing the button 79 after the second-sided copy is completed and before returning to the standard mode. Although not shown, when copy sheets are stored in the relay tray 17, it is thought that the sheets are stored unevenly in the direction (Z direction) perpendicular to the direction in which the sheets travel (X direction). On the path 46, there is a so-called "width alignment" mechanism that positions the copy paper sent out from the relay tray 17 in the Z direction. The copy paper that has been properly positioned is sent out for the process after transfer. [Explanation of each mode] The operation of the machine during single-sided copying and double-sided copying has been explained above.
The operation in copying the first side of both sides is called "first side copying mode", and the second side is called "second side copying mode",
Furthermore, we have added the terms ``standard mode'' and ``copy mode,'' and their meanings are summarized below. "Copying mode" refers to the functions of the copying machine that can be designated and selected by the operator, and in this embodiment, refers to each function illustrated as the operation section in FIG. 2. "Standard Mode" During the copy mode mentioned above, when the machine is turned on or after a certain copying process is completed, if a predetermined period of time has elapsed without continuous copying, the mode is automatically held in the commonly used standard copy mode. Ru. The standard modes for each copy mode are as follows. Magnification: 1 (1:1) Copy density: Normal Paper feed port: 2nd paper feed tray 19 Output port: Tray Copy format: Simplex Set number of sheets: 0 | 0 | 1 Number of copies completed: 0 | 0 | 0 "Single-sided copy" When each copy mode including "mode": "single-sided" is selected, the conveyance path 27 is automatically switched to the designated exit side (position b or c) in response to a copy start signal. Copy paper is the first
Paper feed tray 18 Second paper feed tray 19 or relay tray 1
The sheet is sent out from one of the designated paper feed sections 7, and is discharged from the conveyance path 27 to a designated exit through the processes of exposure, transfer, development, and fixing. "First side copy mode": When "both sides" is selected, the "first side" is displayed, another copy mode is selected, and the conveyance path 27 is switched to position a by a copy start signal. The copy paper is sent out from the paper feed unit designated by either the first paper feed tray 18 or the second paper feed tray 19, and after passing through the processes of exposure, development, and transfer, is fed into the relay tray 17 from the conveyance path 27 and stored therein. Ru. When a limited number of sheets have been stored (details will be explained later, but this is not necessarily the case), the machine will stop and the "second page" will be automatically displayed. "Second side copy mode" After each copy mode is selected (exit, number of sheets set, duplex, and single side modes are not necessary as they are done for the first side), the conveyance path 27 is moved to position a by the copy start signal. The copy paper in the relay tray 17 is then sequentially sent to the conveying path 46, exposed, developed, transferred, and fixed, and then transferred to the opposite side of the first side (the second side). ) and is discharged to a designated exit. After discharging the set number of sheets (details will be described later, but this is not necessarily the case), the machine stops and the "first page" is automatically displayed. [Description of processing at the time of stop input and various abnormalities] Next, processing for paper jams, double feeding, and special operations during the above-mentioned double-sided copying cycle will be described. (When inputting a stop during copying of the first side) () First, if the "Stop" button 45 is pressed during copying of the first side, the copying ends at that point and the number of sheets for which the first side has been copied (relay tray 17
The number of sheets stored in the second side) is automatically displayed as the set number of sheets for the second side, and at the same time, the lamp PL10 is turned on and the mode shifts to the second side copy mode. The main reasons for the "stop" during copying of the first side are thought to be errors in the number of copies, incorrect settings for density and exit mode, and misplacement of originals. If the set number of sheets is transferred to the set number of sheets for the second side when the first side is copied continuously, the difference between the number of sheets in stock in the relay tray 17 and the set number of copies to be made for the second side This will cause a difference in the results and be inconvenient. In addition, considering other factors, there may be cases where the copy paper in the relay tray 17 is miscopied and there is no need to copy the second side of the copy paper, so the number of stock copies in the relay tray 17 and the new set number of copies may be changed. It is not a good method to automatically set the sum to the set number of sheets for the second side. Therefore, when a "stop" is performed during copying of the first side, it is assumed that the first side has been completed at that point, and the mode automatically shifts to the second side copying mode. Here, if the operator considers the copy paper in the relay tray 17 to be a normal copy, the second side copy can be performed. If this is considered to be a copy error, the copy paper can be removed from the relay tray 17 and a new copy of the first side can be made from the beginning. At this time, when the copy paper is removed from the relay tray 17, this is detected and the state automatically shifts to the state of first side copying such as display. At this time, all copy mode holds are released. Here, it is possible to manually remove the copy paper from the relay tray 17, but when the "Remove" button 48 in FIG. 2 is pressed, processes such as exposure, development, transfer, and fixing are performed. Only the paper conveyance function operates without any paper transfer, and the paper is automatically sent out from the relay tray 17 and is discharged onto the tray 31 or into a predetermined bin of the sorter 30 via positions b or c of the conveyance paths 46, 22, and 27. be done. In this embodiment, a dust box 49 is provided at the bottom of the sorter 30, and the rejected copy sheets are automatically fed into the dust box 49. In addition, the tray 31 has a copy paper sorting function by swinging the tray as known from Japanese Patent Application Laid-Open No. 54-41732.
1 is swung and is sorted from normal copy paper. Therefore, the operator can easily sort the copies into normal copies and erroneous copies in both the tray 31 and the sorter 30. (When there is no paper left while copying the first side) () If the remaining amount of paper on the first paper feed tray 18 or the second paper feed tray 19 becomes zero while copying the first side, the procedure described in the previous paragraph () will be applied. As in the case where the stop button 45 is pressed, it is assumed that the first side copy mode is completed at this point.In other words, when the remaining amount of paper becomes zero, copying in the first copy mode is completed and the relay tray is At the same time, the number of sheets stored in 17 is automatically displayed as the set number of sheets for the second side copy mode, the lamp PL10 lights up, the mode shifts to the second side copy mode, and the second side copying starts with the copy start on signal. Ru. Here, as copying progresses, the number of copies is added, and when the set number of copies matches the number of copies, the second side copy mode ends. Furthermore, when the second side copy mode is finished, the initial set number of copies and the finished number of copies are displayed, the lamp PL9 lights up, and the first
You can shift to the double-sided copy mode and request copies of the missing amount by following the steps below. At this point, by replenishing the first paper feed tray 18 or the second paper feed tray 19, where the amount of paper remaining previously became zero, with copy paper, a state is reached in which copying of the insufficient amount can be started. Next, when the copy button 35 is turned on, the first
The surface copying is restarted, and the number of copies is sequentially added to the number of copies completed. Copying further progresses, and when the set number of copies matches the number of copies, copying in the first side copy mode ends, and at the same time, the second side copy mode is entered, and the first side copy mode is restarted for the second time. The previous display, that is, the initial set number of copies and the number of copies to be completed, is displayed again. The second side copying is restarted by the next copy button and the on signal, and the number of copies is sequentially added to the number of copies completed above, and when the set number of copies and the number of copies match, the copying in the second side copying mode ends and the first All the desired double-sided copies can be obtained. Here, the number of copies will be specifically substituted for the above embodiments, and the operation and status of each will be clarified. Assuming that the desired copy setting number is 20 and the number of copies stored in the paper feed tray is 15, the first side copy mode starts with the copy start on signal when the first side copy mode display and the number of copies display 20-0. The number of copies displayed is 20-0, 20-1, 20.
-2, . . . 20-11, 20-12, 20-13, . . . , and the copied paper that has been copied is introduced into the first paper feed tray 18. Display number of copies here 20
-15, the remaining amount of paper on the paper feed tray becomes zero and the first side copy mode stops and ends. When the first side copying is completed, the first side copying mode shifts to the second side copying mode, and the copy number display shifts from 20-15 to 15-0. In other words, the set number of copies changes to 15. Next copy start, copying on the second side starts with the on signal, and as copying progresses, the number of copies is added, and the number of copies is displayed as 15-0, 15-1, 15-
The process progresses in the order of 2, . Here, when the number of copies and the set number of copies match, that is, when the number of copies displayed is 15-15, the second side copying stops and ends. When the second side copying is completed, the second side copying mode shifts to the first side copying mode, and the copy number display shifts from 15-15 to 20-15. In other words, preparation is made for the insufficient number of copies (5 copies), which is the final copy number of 15 copies compared to the initial set copy number of 20 copies. Next, by replenishing the paper feed tray where the remaining amount of paper has become zero, copying of the insufficient amount can be started. Copy start, the second first side copy mode starts with the on signal, and as copying progresses, the number of copies is added, and the number of copies is displayed as 20-15, 20.
-16, 20-17... and so on. Then, the copy-completed paper that has been copied is introduced into the relay tray 17. Here, when the number of copies and the set number of copies match, that is, when the number of copies displayed is 20-20, the first side copying stops and ends. When this first side copying is completed, the first side copying mode shifts to the second side copying mode, and the copy number display shifts from 20-20 to 20-15. With the next copy start on signal, the second side copying using the second side copying mode is started, and as the copying progresses, the number of copies is added, and the number of copies is displayed as 20-15, 20-16, 20-17, etc. ...and it progresses. Through the above-described operations, the copy paper on which double-sided copying has been completed is introduced into the subsequent copy paper processing department. Here, when the number of copies and the set number of copies match, that is, when the number of copies displayed becomes 20-20, the second side copying stops and ends, and the desired set number of copies is all achieved. As described above, even if the remaining amount of paper occurs during copying, it is possible to continue copying, but the present invention is not limited to the specific example in the above-mentioned method for displaying the number of copies. It will not be done. In other words, when the amount of paper remaining becomes zero and the mode shifts from the first side copy mode to the second side copy mode, the copy number display in the specific example changes from 20-15 to 15-0, but from 20-15 to 20- It is also possible to shift to 0. Furthermore, from the second side copy mode, the second
When switching to side copy mode, the number of copies displayed is 15.
-15 or 20-15 in accordance with other transition displays from the first side copy mode to the second side copy mode, or 5-0.
It is also possible to shift to the display. Furthermore, when shifting from the second first side copying mode to the second second side copying mode, the copy number display can also be changed from 5-5 to 5-0. As another example, it goes without saying that a subtraction type display of the number of sheets is also possible. As is clear from paragraphs () and (), in this embodiment, if image formation on the first surface is interrupted before the desired number of image formations is completed using the input key as an input means, the storage section An image is continuously formed on the second surface of the image carrier (copy paper) in the relay tray. With this configuration, it is possible to continue forming images on the second side even if paper runs out or the like occurs during image formation on the first side, and it is also possible to replenish the image carrier while forming images on the second side. Therefore, waiting time can be eliminated, which is very useful. (When inputting a stop while copying the second side) () Next, if the "Stop" button 45 is pressed while copying the second side, the copying operation will stop, but the display and the "duplex" mode and number of copies will not be set. When the button 35 is held and the next copy start button 35 is pressed, the copying operation is restarted and the number of copies displayed is added to the number before the stop. At this time, if the copy paper is removed from the relay tray 17, the display and copy mode automatically shifts to the first side copying mode, similar to the first side copying. The reason why the "stop" button 45 is pressed when copying the second side may be the same as that for the first side, and if the mode is changed to the first side copying mode and the number of copies can be newly set. This causes a discrepancy between the number of sheets stored in the relay tray 17 and the set number of sheets, which is inconvenient. As described above, when an interruption signal is generated during copying of the second side, the second side is
Retains side copy mode. Therefore, it is already the first
Among the copy sheets on which the image is formed, the copy sheets on which the second side cannot be copied yet are stored as valid copy sheets in the relay tray 17 serving as a storage section. (When a paper jam occurs while copying the first side) () Next, if a paper jam occurs while copying the first side, the operation is the same as for single-sided copying, and the detection device 36
Or, if a paper jam is detected at 37 or 38, the paper existing after the separating section 21 is stored in the relay tray 17 after undergoing a fixing process. When a paper jam is detected by the detection devices 38 and 39, the copy paper before the detection point must be removed.
Subsequent copy sheets are fed into the relay tray 17. When the next copy starts, it will be added to the number of copies that were completed on the first side at the time of the paper jam. (When a paper jam occurs while copying the second side) () Next, if a paper jam occurs while copying the second side, the number of copies will be added when the next copy starts, but the paper will be removed due to the jam. Therefore, the number of copies becomes insufficient compared to the set number of copies. The double-sided copying apparatus of this embodiment is configured to correct this shortage. First, after canceling the jam mode, complete copying of all remaining copy sheets in the relay tray 17, and at that point automatically return to the first side copying mode while displaying the number of completed duplex copies and the desired number of copies set in advance. At the same time, the lamp PL9 lights up to display the message "PLEASE PLACE THE FIRST SIDE OF THE ORIGINAL" and it becomes possible to copy the missing amount. When the next copy button 35 is turned on, the first
Side copying is started, and when the number of sheets to be copied is sequentially added to the set number of sheets to be copied and the set number of sheets is equal to the number of sheets to be copied, the first side copying mode is ended and the second side copying mode is entered. At this time, the lamp PL10 lights up and displays the message "Please place the original on the second side", and the number of copies to be completed and the set number of copies before the second copying of the first side is displayed again. . Next, when you turn on the copy button, copying on the second side is resumed, and the number of copies completed is added to the number of copies displayed again above. When the number of copies completed and the set number of copies match, the copying operation stops, and the next The system enters a waiting state for double-sided copying. When automatically transitioning to the second side copy mode and the second side copy mode, each mode selected at the first time, such as magnification, density, tray or sorter, etc., is memorized. It is now set automatically. Further, when the second copy of the first side is automatically set, if the missing number is not desired, the automatically set copy mode can be canceled by pressing the clear key. Since there is no copy paper in the relay tray 17 at this time, no inconvenience will occur even if another mode is newly set. In addition to this embodiment, it is also possible to correct the shortage of sheets due to a jam when copying the second side in the following manner. In the same manner as in the above example, copying of the second side of all the remaining copy sheets in the relay tray 17 is completed, and at that point, the number of sheets that have been duplexed completely short of the set number of sheets is automatically updated. will be displayed as the set number of sheets, return to the first side copy mode, and at the same time ask "Please place the original on the first side."
display. At this time, it is natural to automatically set each of the first-time copying modes that have been stored when returning to the second-time first side copying mode, similarly to the embodiment described above. Another example is a case where the number of sheets is displayed in a subtractive manner, but in this case, the number of uncopied sheets displayed when the second side of all copy sheets in the relay tray is completed is the number of missing sheets. Yes, the machine automatically switches to the first side copy mode, displays the message "Please place the original on the first side," and sets each copy mode that was memorized for the first first side copy. Just do it. In addition, when the sorter 30 is used for this double-sided copying, the missing copy paper for the second copy is fed from the bin next to the final bin that was sequentially fed in for the first copy. There is. (Double feeding during copying of the first side) () If there is double feeding of paper during copying of the first side, there are more copy sheets than the set number in the relay tray when copying of the second side is started. In this embodiment, the second side copying is executed until all the copy sheets in the relay tray 17 are used up. At this time, the number of copies completed on the lower display will be displayed as a number greater than the set number of copies. As described above, images are formed on the second surface of all the image carriers present in the storage means regardless of the number of settings made by the input keys as the setting means, so double feeding occurs when images are formed on the first surface. Even if there is an image carrier on which an image is not formed on the first surface due to the above, it is possible to reliably obtain a set number of image carriers on which an image is formed on both the first and second surfaces. (When double feeding occurs while copying the second side) () If double feeding occurs while copying the second side, the number of copies to be completed will be insufficient compared to the set number of copies, as is clear from the above () and (). In this embodiment, when the number of sheets of image carrier (copy paper) on which images are formed on both sides does not reach the number set by the input key as a setting means, the first side is automatically changed after image formation on the second side is completed. A transition is made to the first mode for surface copying. With this configuration, the necessary number of image carriers can always be obtained in just the right amount. Furthermore, each copying mode such as the magnification, paper feed port, density, etc. in the first mode is memorized, and the
At the same time as the mode is returned, each copy mode also returns to the same mode as the first time, so the user does not have to set the mode again, which is very convenient. (In the event of a power outage or power outage) () Next, in rare cases, if the power to the machine is cut off due to a power outage or an operational error during double-sided copying (both the first and second side copying), the power will be turned off again. When the power is turned on, the memory of the previous copy mode is erased and all copy modes shift to standard mode.
If there is copy paper in the relay tray 17 at this time,
When the operator selects duplex copy mode again,
The lamp PL11 lights up and the message "Remove copy paper in relay tray" is displayed, and the copy paper is removed until it is removed.
Copying is not possible. Furthermore, if the operator selects the single-sided copy mode at this time, the copy paper in the relay tray 17 does not become an obstacle during single-sided copying, so copying can be performed without removing the copy paper in the relay tray 17. It is possible. Here, if the copy paper in the relay tray 17 is a normal first-side copy finished paper, the copy paper is manually loaded into the first or second paper feed table and one-sided copying is performed. , the second side can be copied and a double-sided copy complete paper can be made. As described above, if there is copy paper in the relay tray serving as a storage section, the transition to the first side mode of double-sided copying is prohibited. (During interrupt copying) () Next, this embodiment has an interrupt function as one of the copy functions. Interrupt copying is possible only during single-sided copying, and interrupts are not allowed during double-sided copying. Regarding interruptions during single-sided copying, since the relay tray 17 is not used, it is possible to perform both single-sided copying and double-sided copying. During single-sided copying, if the "Interrupt" button is pressed, the copying operation will stop. At this time, all copy modes automatically shift to the standard mode, but all copy modes before the interrupt button is pressed are stored. During interrupt copying, it is possible to arbitrarily change the mode from the standard mode described above and set a new number of copies. When the interrupt copy is completed, the stored copy mode is automatically restored and continues when the copy button is pressed. [Description of Control Circuit] Description will be given based on the electric circuit diagrams shown in FIGS. 3 and 4. In Figure 3, the CPU is a 4-bit parallel processing microprocessor with RAM (256
×4bit) and program section ROM (4K×8bit) and 4bit
It has input/output L/O devices I/O1 to I/O8. Of these, Key Sw is connected to a dedicated I/O device I/O-5 (for example, μpD757 manufactured by NEC) for 7-segment display. I/O devices and loads are connected through drivers and input interfaces, as is well known. The control is to perform sequence control according to a program determined in advance in the ROM. [Description of Program] Figs. 6 to 7 show the general flow of this program, and Figs. 8 to 14 show subroutines. (Explanation of general flow) To explain the operation from these flowcharts, when the main switch (not shown) is turned on,
The CPU starts operating from program address '000'. First, use Stop1 to set all RAM data at addresses '000'' to OFF'' to 0. Next, since the output port is not specified when the power is turned on, the output port is set to 0 and all loads are turned off. The fifth button is used to output the set number of sheets and the number of copies at Stop2.
CNT1 (number of sheets set) shown in the RAM map in the figure,
CNT1 = 001 in the memory of CNT2 (number of copies),
Store CNT2=000. Next, set the mode to “024” to “029” in the RAM map.
=0 “025” = 2 (original exchange lamp ON) “026” = 0
“027” = 8 (1:1 display), “028” = A (normal, tray indicator lamp ON), “029” = 1 (lower cassette, lamp ON), and output the contents of RAM through the I/O device. . In Step 3, perform the following processing depending on whether there is a Key input. If there is a Key input, it processes the Sub Key and sets the necessary data in RAM based on the Key input data. In Step 4, if the key counter is checked, do nothing and proceed to the next step, but if not, if the copy key is pressed in Step 3, a copy flag is set, and if this is set, the program moves to the copy sequence. Therefore, reset it here so that it will not work without a key counter. In Step 5, depending on the contents of the RAM set in each mode in Steps 2 and 3, the sub reduction is first performed to set the RAM at the specified position. Next, adjust the concentration using Sub concentration.
Do the same for the exit as well as setting it to the specified position in RAM. In Step 6, it is checked whether the fixing heater is capable of fixing, and if the fixing temperature has not been reached, the wait lamp is turned on and the copy flag is reset so that copying is disabled, as described above. If the fixing temperature has been reached, turn off the wait lamp and proceed to the next step. In Step 7, the presence or absence of paper in the relay tray is checked, and if there is paper, the relay tray ejection subroutine is executed (Figure 14), but this subroutine is programmed so that the paper in the relay tray is ejected only in single-sided mode. has been done. In Step 8, the paper out lamp is turned on or off depending on whether there is paper in the selected cassette, and if there is no paper, the copy flag is also reset. Step 9 If the copy flag is set, reset the necessary flags and move on to the copy cycle.
If it is not set, return to Step 3, Step 3～
I am taking back Step 9. The steps up to this point will be referred to as the standby routine. Hereafter referred to as the copy routine. Step 10 The copy button is pressed, various Sets are made in the standby routine, and copying begins. The main motor rotates and the light source, document scanning, charging, development, paper feeding, etc. necessary for image formation are performed repeatedly according to the sequence, but the next Step 11 and subsequent steps are inserted at one or more locations in the repeated loop. I'll keep it. The figure shows only one location, JAM check, interrupt check, and SET.
A number of sheets completion check, a stop instruction check, a paper out check, etc. are included, and when these are detected, other processing is performed. These different processes are shown in Figures 9, 10, and 11.
This will be explained using FIG. First, in FIG. 7, if a jam is detected in Step 11, the process proceeds to a jam routine. Also, interrupt key
When is pressed, the process goes to Step 12. In Step 12, interrupts are not accepted if the mode is double-sided. Allow interrupts only when copying one side, and when an interrupt is received, the mode that was being copied in the current mode,
Figure 5 shows the data for the number of copies and the set number of copies.
CNT1 saves CNT4, CNT2 saves CNT5, and RAM addresses "024" to "029" are saved to "054" to "059". Then, set the interrupt start flag to RAM address "079". Then it goes back to standby. Key input is possible in standby.
When you press a key, you can select each mode depending on the key you pressed. You can also input a new number of sheets settings. And it can be copied only once in interrupt mode. If there is no interruption, go to STEP13. In STEP 13, when the set number of sheets and the number of copies match and the first side is being copied on both sides, the first side data is saved to RAM "034" to "039".
This is to remember that if you jam on the second side, it will run out and you will have to make the first side again. Also, when performing the second side of duplex printing, even if the set number of sheets and the number of copies are equal to 1, if there is paper left in the relay tray, a large number of sheets may be fed due to double feeding, etc. Copy the surface and extract as many valid copies as possible. In Step 14, it is checked whether or not the stop key is pressed, and if the stop key is pressed, processing is performed in Sub STOP. This will be explained with reference to FIG. In Step 15, the presence or absence of paper in the paper feed cassette is checked, and if there is no paper, the 11th step is processed by Sub PEMP.
This will be explained with a diagram. In step 16, in the second side mode during double-sided copying, the relay tray is effectively out of paper, so the process jumps to that shown in FIG. 11 and the subsequent processing is performed.
That is, the PEMP2 flag is set, the first side mode is set again, and the remaining amount is copied to obtain the required number of copies. (Description of Subroutines) Next, each subroutine will be explained. Sub Key: The values in the table below are stored in the working registers WR(b) and WR(M) (corresponding to RAM addresses "018" and "01C") by the pressed keys. This data determines what key it is, and the required portion of RAM is set according to the key. For example, if the reduced 0.7Key is pressed, the RAM address “027”
The bit at weight 4 is set to "1". In this case, the keys to not execute are selected depending on whether the key restriction flag is set or not.
This is to make it impossible to change the mode key in the case of JAM, paperless, etc., so that only the key CL and key Cpy are accepted. The key CL is the key to cancel the previous mode.

[Table] Sub JAM: When a jam occurs in single-sided mode, the JAMS flag is set and the I/O for the jam is reset and stabilized. Further, in order to display the effective number of copies, the number of completed copies CNT3 is transferred to the number of copies CNT2. It then sets the key restriction flag and returns to standby. The same process is performed for the first side in duplex mode, but the JAM1 flag is set instead of the JAMS flag. In duplex mode, JAM on the second side sets the JAM2 flag. If there is no paper depending on the presence or absence of paper in the relay tray,
Set the PEMP2 flag, call up the first side mode, and set each mode to the first side mode.
This is to ensure the necessary number of copies since even if one wanted to continue duplex copying on the second side, it would not be possible due to lack of paper. After the jam, the I/O process is performed and the system waits until the jam reset button (not shown) is pressed. Sub STOP: When the STOP key is pressed during copying,
Set a flag depending on whether it is double-sided or not. In single-sided mode, set the STOPS flag, set the key-only flag, and set the 7th
Jump to figure. Then it goes back to standby. Similarly, if it is on the second side of both sides, the STOP2 flag is set, the key restriction flag is set, and the process jumps to FIG. In the case of the first side of both sides, after setting the STOP1 flag, in order to complete the duplex copy first, the set number of copies is saved, the number of completed copies is set as the number of copies, and the mode is shifted to the second side. In this case, no key restriction is provided and a separate process for key input is performed using the STOP1 flag. Sub PEMP: This is a routine to check if there is no paper in the copy, but checks to see if there is paper in the selected paper feed cassette. If there is paper in the selected cassette, nothing is done, but if there is no paper, it determines whether it is double-sided or single-sided, and if it is single-sided, it sets the PEMPS flag and jumps to Figure 7. In the case of both sides, processing is performed depending on whether it is the first side or the second side. In the case of the first side, the PEMP1 flag is set, the set number of sheets is saved, the number of copies is transferred to the set number of sheets, and the number of copies is cleared. Then switch the mode to the second side mode and
Jump to figure. This is so that if you run out of paper on the first side, you can make the missing copy again after completing all double-sided copies. Since paper is sent from the relay tray during the second page, the presence or absence of paper in the relay tray means that there is virtually no paper. If there is no paper here, set the PEMP2 flag, set the 1-page mode, and do the rest from the 1st page. Sub exit switching Determine whether it is duplex mode or single-sided mode, and if it is single-sided mode, determine whether to specify a tray or a sorter. If sorter is specified, check whether it is at the sorter position. If it is not at the sorter position, turn on motor M3 and clutch Cl6 and rotate it until it is at the sorter position. When it reaches that position, turn off motor M3 and clutch Cl6. The same goes for the tray. In the case of double-sided paper, the exit designation on the first side (Side 1) is the position of the double-sided relay tray, whether it is a tray or a sorter, so the operation of checking whether there is an exit at the double-sided position is the same as described above. Only when the second screen mode is activated can you switch to the designated exit. Sub reduction Select whether the reduction is 1:1, 0.7, or 0.6.
Judgment is made based on the data in RAM “027”. 1:1
If so, check if you are in the 1:1 position and set it to 1:1.
If it is not in position, turn on the reduction motor M4 and 1:
Continue turning until it reaches position 1. The same applies to 0.7 and 0.6. Sub relay tray ejection: It is strange that there is paper here other than in the duplex, so it is displayed to eject paper and is ejected by pressing a button. That is, if the paper is not double-sided and there is paper in the relay tray, the "Please remove paper" lamp is turned on to see if the paper ejection key is pressed and waits until the key is pressed. When pressed, the main motor M1, fixing motor _M3, duplex paper feed clutch, and registration clutch are turned on to eject the paper from the relay tray (all paper buses are operated), and the paper is ejected to the tray through the conveyance system. let Perform the paper ejection sequence until the relay tray runs out of paper. As described above in detail, a double-sided image forming apparatus that is easy to use is realized. [Effects of the Invention] As explained above, according to the present invention, the first side image formation is performed a set number of times, and the second side image formation is performed regardless of the set number of times, and the record of the first side image formation is recorded. Since image formation is continued until there is no recording material left in the storage means that stores the materials, there is a possibility that double feeding of recording materials may occur during image formation on the first surface and more recording materials than the set number are stored in the storage means. Even in such a case, it is possible to reliably obtain a set number of recording materials on which images are formed on both sides.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of a double-sided copying apparatus to which the present invention can be applied, FIG. 2 is a plan view of the display section and operation section of the apparatus shown in FIG. 1, and FIGS. 3 and 4 are views of the apparatus shown in FIG. FIG. 5 is a diagram showing the memory area of the RAM in FIG. 3, and FIGS. 6 to 14 are diagrams showing control flowcharts stored in the ROM in FIG. 3. In the figure, 2 is a document table, 9 is a photosensitive drum, and 17
18 and 19 are paper feeding units, 27 is a conveyance path, 30 is a sorter, and 31 is a tray.

Claims (1)

[Scope of Claims] 1. A first input means for inputting a desired number of times of image formation; a storage means for storing data of the number of times of image formation inputted from the first input means; a start signal for instructing the start of image formation. a first step of forming an image on the first side of the recording material and then temporarily storing the recording material in the storage means; and forming an image on the second side of the recording material sent from the storage means. second to form
an image forming means for forming images on both sides of a recording material by sequentially performing steps; a detection means for detecting the presence or absence of the recording material in the storage means; and a counting operation in accordance with the image forming operation performed by the image forming means. a counting means for causing the image forming means to start operating in the first step in response to the start signal inputted by the second input means, and counting the amount of data stored in the storage means until the counting means counts the amount of data stored in the storage means; When the image forming operation is performed in the first step and the counting means counts the amount of the stored data, the image forming operation in the first step is completed in response to a count-up signal from the counting means, and furthermore, the image forming operation in the first step is completed. After the first step, the image forming means starts operating in the second step in response to the start signal inputted from the second input means, and the image forming means starts operating in the second step until the counting means counts the amount of stored data. The image forming operation is performed in two steps, and even if the counting means counts the amount of the stored data, no output is output from the detecting means while the detecting means detects that there is a recording material in the storage means. In response to a signal indicating that recording material is present, the image forming operation in the second step is further continued, and when the detection means detects that there is no recording material in the storage means, an output is output from the detection means. A double-sided image forming apparatus comprising: a control means for terminating the image forming operation in the second step in response to a signal indicating that there is no recording material.