JP2004262664A - Sheet conveyance device and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sheet conveyance device capable of stopping a sheet at a position where the sheet can be easily taken out on a sheet conveyance passage in the event of a sheet jam, and to provide an image forming apparatus with the same. <P>SOLUTION: The sheet conveyance device has a sheet conveyance means arranged in the sheet conveyance passage, a sheet detection means detecting the passing of the sheet in the conveyance passage, a conveyance abnormality detection means detecting the abnormality of the sheet conveyance in the passage, a sheet position counter recognizing the position of the sheet in the passage, a sheet stop position determining means determining the proper stop position of the sheet by the counter upon the detection of abnormality by the abnormality detection means, and a stop control means controlling the sheet to be stopped at the stop position determined by the position determining means. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

  The present invention relates to sheet processing in an image forming apparatus such as a copying machine, a printer, and a facsimile.

  In a conventional image forming apparatus, when a jam occurs in a sheet being conveyed, a control for immediately stopping a clutch or a drive motor for transmitting drive to a conveyance system is generally performed. Then, a sheet disposed on the conveyance path is detected by a sensor arranged to detect the passage of the sheet, and a unit of the conveyance path to which the sensor belongs is displayed on the display unit. Thus, the user is configured to remove the stopped jam sheet.

  In recent years, in order to improve sheet removability when a jam occurs, an apparatus in which a sheet conveying path is divided into a plurality of units and these units are configured to be detachable from the apparatus main body has been provided. I have.

  However, in the above-described apparatus configured with a plurality of units that can be attached to and detached from the apparatus main body, if the transport drive system is immediately stopped when a jam occurs, both the detachable and adjacent units are separated. One sheet may stop. At that time, when only one of the units was pulled out, there was a problem that the sheet was broken. Further, as the size of the apparatus decreases, the sheet conveyance path is complicatedly curved, and it becomes difficult to remove a jammed sheet.

  An object of the present invention is to solve the above-described problems, and an object of the present invention is to provide a sheet conveying apparatus capable of stopping a sheet at a position where it can be easily taken out on a sheet conveying path when a sheet jam occurs, and an image forming apparatus including the same. It will not be provided.

  A typical configuration according to the present invention for solving the above-mentioned problems includes a sheet conveying unit disposed in a sheet conveying path, a sheet detecting unit for detecting passage of a sheet in the sheet conveying path, and a sheet in the sheet conveying path. Conveyance abnormality detection means for detecting conveyance abnormality of the sheet, a sheet position counter for recognizing the position of the sheet in the sheet conveyance path, and a sheet position counter for detecting a sheet conveyance abnormality by the conveyance abnormality detection means. And a stop control means for stopping the sheet at the stop position determined by the sheet stop position determining means.

  The sheet conveying device according to the present invention can provide a sheet conveying device that can stop a sheet at a position where it can be easily taken in consideration of sheet removability when a jam occurs in a sheet being conveyed. Further, by recognizing the stop position of the sheet on the sheet conveyance path by the position counter, the accuracy of recognizing the jam processing position is improved, so that the sheet to be removed can be efficiently and reliably removed.

  An embodiment of a copying machine adopting an electrophotographic method as an example of a sheet conveying apparatus and an image forming apparatus having the same will be specifically described with reference to the drawings. FIG. 1 is a schematic configuration diagram of a copying machine having a sheet conveying device, FIG. 2 is a block diagram of a control device of the copying machine having a sheet conveying device, FIG. 3 is a diagram showing an arrangement configuration of an operation panel, and FIG. FIG. 5 is an explanatory view of an original reading operation by reading, FIG. 5 is a perspective view showing a detachable unit and an openable unit provided in the apparatus main body, FIG. 6 is a perspective view showing an open / close state of an upper right door unit, and FIG. FIG. 8 is a perspective view showing a state in which the unit is pulled out to the front, FIG. 8 is a flowchart showing control of a sheet feeding operation task, FIG. 9 is a flowchart showing control of a sheet feeding task, and FIG. 10 shows control of a jam display task. 11 is a flowchart illustrating control of a sheet removal process, FIG. 12 is a flowchart illustrating control of a post-jam processing task, and FIG. 13 is a flowchart illustrating control of jam monitoring. It is over door.

  In FIG. 1, a copying machine 1 includes a circulation type automatic document feeder 2 (RDF) for automatically feeding a document, and an image forming apparatus main body 3. Are combined.

  The apparatus main body 3 includes a document table glass 5 as a document table on an upper portion, and an optical system 6 as an image reading unit below the document table glass 5. The optical system 6 includes an exposure lamp 6a, a scanning mirror 6b, a zoom lens 6c, and a motor (not shown). Then, the original is illuminated by the exposure lamp 6a, and the reflected light from the original is radiated by the scanning mirror 6b and the zoom lens 6c to the photosensitive drum 7a serving as a toner image carrier. There are the following two methods for irradiating the photosensitive drum 7a with light reflected from a document. One method is to move the optical system 6 such as the exposure lamp 6a with the original fixed on the platen glass 5, and to fix the original with the optical system 6 such as the exposure lamp 6a fixed. There is a method of moving the original on the glass plate 5 (hereinafter referred to as "flow reading").

  Below the optical system 6, an image forming unit 7 as an image forming unit is arranged. The image forming unit 7 includes a photosensitive drum 7a rotatably arranged in the direction of arrow a, a high-pressure unit 7b arranged around the photosensitive drum 7a, a blank exposure unit 7c, a potential sensor 7d, and a developing device. 7e, a transfer charger 7f, a separation charger 7g, and a cleaning device 7h. The photoreceptor drum 7a is driven to rotate by a main motor (not shown), is corona-charged by a high-voltage unit 7b, and is irradiated with reflected light of a document from the optical system 6 to form an electrostatic latent image. The electrostatic latent image is developed by the developing device 7e and is visualized as a toner image.

  On the other hand, a lower cassette of the apparatus main body 3 is provided with a first cassette 9a, a second cassette 9b, a third cassette 9c, and a fourth cassette 9d. Each of the cassettes 9a to 9d is provided with pickup rollers 10a to 10d for feeding out the sheets S stored in the cassettes 9a to 9d. Further downstream, separation roller pairs 11a to 11d for separating and feeding the sheets S respectively fed by the pickup rollers 10a to 10d are arranged, and the uppermost sheet S is separated one by one. The separated sheet S is conveyed to registration rollers 13 provided in front of the image forming unit 7 by conveyance rollers 12a to 12d arranged further downstream.

  In the vicinity of the image forming unit 7, a multi-manual feeding device 14 that conveys the sheet S to the image forming unit 7 by manual feeding is provided. Further, downstream of the image forming section 7, a transport belt 15 for transporting the sheet S on which an image has been formed further downstream, and a fixing device 16 as a fixing unit are provided. The fixing device 16 fixes the toner image on the sheet S by heating and pressing the sheet nipped and conveyed by the fixing rollers 16a and 16b. A discharge flapper 17 is disposed in the vicinity of the downstream side of the fixing device 16, and a discharge path A1 for discharging the sheet S to the outside of the apparatus main body 3; The mode is switched as appropriate to the re-transport path A2 for performing multiplex recording. A discharge roller 19 is provided in the discharge path A1.

  Below the fixing device 16, a transport path 20 connected to the re-transport path A2 is provided. Downstream of the transport path 20, a temporary storage tray 23 for temporarily storing the sheet S conveyed after image formation, a temporary storage tray discharge roller 21 for discharging the sheet S thereto, and a temporary storage tray 23 A discharge sensor 22 for detecting the discharged sheet S is provided. The discharge sensor 22 also functions as a sheet detecting unit for detecting the passage of the sheet S and a conveyance abnormality detecting unit for detecting a conveyance error of the sheet S. In the vicinity of the discharge sensor 22, there is provided a re-feed device 34 for sequentially re-feeding the sheets S stored in the temporary storage tray 23.

  A re-feed roller 31 for re-feeding the stored sheets S is disposed near the feed port of the temporary storage tray 23. Further, a re-feeding roller 32 and a re-feeding separation belt 33 abut on the downstream side, so that the sheets S are separated and re-feeded one by one. As shown in FIG. 1, the temporary storage tray 23 has a structure inclined at a predetermined angle to assist in reaching the re-feed separation belt 33 when the stored sheets S are re-fed. ing.

  A multiple flapper 36 is disposed near the downstream side of the re-feeding roller 32 and the re-feeding separation belt 33. Downstream of the multiplex flapper 36, a reverse transport path 37 and a transport path 39 are provided. The reversing conveyance path 37 extends upward, and when performing multiple recording on one recording surface of the sheet S, an image of the sheet S to be conveyed is recorded in a multiplex manner on the recording surface of the sheet S Here, the formation surface is once inverted. The conveyance path 39 extends downward so that the image forming surface of the sheet S is reversed and the other recording surface is conveyed to the image forming unit 7 again when performing double-sided recording. The sheet S is conveyed to the reverse conveyance path 37 or the conveyance path 39 by appropriately switching the multiplex flapper 36 according to the recording purpose.

  In the transport path 39, transport rollers 40a to 40d are sequentially arranged. At a predetermined position on the sheet conveyance path arranged in the apparatus main body 3, a sheet detection means for detecting the passage of the sheet S and a conveyance error detection means for detecting a conveyance error of the sheet S in the sheet conveyance path. Are also provided.

  FIG. 2 shows a block diagram of the control device. The control device 100 controls the entire apparatus of the copying machine 1. The control device 100 includes, as a procedure or a module of a control program, sheet transport control means, stop control means for forcibly stopping a transfer sheet during image formation, and other control means. Have implemented the means. The control device 100 includes a CPU 101 for controlling the entire copying machine 1 according to control means stored in a read-only memory (ROM 102), a ROM 102 for storing a control procedure (control program) for the control device 100, A random access memory (RAM 103), which is a main storage device used as a work storage area, etc .; an output of a control signal of the CPU 101 to driving means such as a main motor; Processor 104 (I / O).

  FIG. 3 shows an example of an arrangement configuration of an operation panel 200 provided in the apparatus main body 3. In FIG. 3, a user mode key 601 is turned on / off by an operator (user) for automatic sorting, ON / OFF for taking out before the sorter, ON / OFF for both sides of the skip, ON / OFF for the automatic start of the manual feeder feed, and automatic ON / OFF for the cassette. Selection ON / OFF, buzzer ON / OFF setting, slightly smaller mode change, preheating mode setting, specification setting initialization, standard mode change, auto clear time change, auto power off time change, weekly timer Setting, day / time setting, zoom fine adjustment, feeder cleaning, wire cleaning, and other settings and adjustments.

  The all reset key 610 is pressed when returning to the standard mode. A copy start key 605 (copy start key) is pressed to start copying. The clear key 604 is used to release the set number of copies. A stop key 609 is pressed to interrupt continuous copying. After the copying at the time when this key is pressed is completed, the copying operation of the apparatus is stopped.

  A ten key 608 is pressed to set the number of copies. The guide key 602 is used to display a description of a function corresponding to various keys on the message display 615. A preheating key 607 is pressed to set a preheating mode. This key is a self-illuminated key provided with a light emitting element such as a light emitting diode, and lights up in the preheating mode.

  The interrupt key 606 interrupts during a copying operation and is pressed to make another copy. This key is also a self-illuminated key similarly to the above-described preheating key 607, and is lit when an interrupt is received, and is lit during interrupt copying.

  The message display 615 is a display unit that displays an operation procedure of the device. The message display 615 has an LCD (liquid crystal) type touch panel, and displays characters and graphics at 240 × 320 dots to display various information related to copying.

  In the message display 615, in the standard state, a mode for fixed-size variable-size key, same-size key, zoom key, slightly smaller key, sheet selection key, copy density key, sorter key for selecting the function of the sorter, and duplex copy mode is set. Double-sided key to perform other operations such as frame erasing, binding margin, cover / insert, reduced layout, enlarged layout, OHP sheet insertion, continuous page copying, multiplexing, mixed original, photo, mode memory, etc. An application mode key for setting a mode is displayed, and by touching a portion corresponding to each key, a window relating to the content is further displayed. In addition, an operation procedure when a sheet jam or an error occurs is also displayed.

  FIGS. 4A to 4F are explanatory diagrams of an original reading operation by moving reading. First, the original D is set in the automatic document feeder 2 (see FIG. 4A), and when the copy start key 605 is turned on, the second original D2 in which the automatic document feeder 2 is located at the lowest position is shown in FIG. 4A, the document is fed to the document reading unit 4 from the right side, and at the same time, the apparatus main body 3 moves the optical system 6 to the center of the document table glass 5 and locks the optical system 6 by an optical system locking means (not shown) (FIG. b)).

  When the second document D2 is conveyed immediately before the optical system 6 (see FIG. 4C), the automatic document feeder 2 sends an image signal to the apparatus main body 3, and the apparatus main body 3 turns on the exposure lamp 6a. Then, the registration roller 13 is controlled according to the image signal (see FIG. 4D).

  At this time, the first document D1 placed on the second document D2 is fed to the document reading unit 4 from the right side of the figure following the second document D2, and is then transferred to the second document D2. Subsequently, the first document D1 is exposed, and the second document D2 is discharged from the left side of the figure (see FIG. 4E). Then, the optical system 6 returns to the home position, and the first document D1 is discharged from the left side of the figure (see FIG. 4F).

  FIG. 5 is a perspective view showing an example in which a sheet conveying path in the apparatus main body 3 is divided into a plurality of units, and these units are configured to be detachable or openable from the apparatus main body 3. 6 is a perspective view showing an open state of the upper right door unit 311 in FIG. 5, and FIG. 7 is a perspective view showing a state in which the fixing and conveying unit 301 in FIG.

  As shown in FIGS. 5 to 7, the fixing and conveying unit 301 includes components from the registration roller 13 to the discharge roller 19 which are integrated. The fixing and conveying unit 301 is provided with a plurality of sheet conveying means such as a registration roller 13, a conveying belt 15, and a discharging roller 19, and the first sheet disposed on the upstream side in the conveying direction inside the fixing and conveying unit 301. The registration roller 13 corresponds to the transport unit. In the temporary storage tray unit 302, the temporary storage tray 23 and the re-feed device 34 are integrated. The re-feeding conveyance unit 303 is integrally formed with conveyance rollers 40a to 40d for conveying the sheet S re-fed from the temporary storage tray 23. The sheet feeding cassette units 304 to 307 include the first- to fourth-stage cassettes 9a to 9d, respectively. Each of the units is configured to be integrally detachable from the apparatus body 3 by being pulled out forward (toward the front side in the figure).

  Further, the manual feed cover unit 310 is configured to be able to open and close the transport path of the multi manual feed device 14. The upper right door unit 311 and the lower right door unit 312 are configured such that a transport path extending above the apparatus main body 3 on which the transport rollers 12a to 12d are arranged can be opened and closed by dividing the transport path into upper and lower parts. The manual feed cover unit 310 and the door units 311 and 312 can be opened and closed with the back side in the drawing as a fulcrum.

  As described above, each unit is configured to be attachable / detachable / openable / closable to / from the apparatus main body 3, and includes unit unattachment detection means and unit openness detection means (not shown) for detecting that each unit is detached / opened / closed. ing. The detached or opened state of each unit detected by these detecting means is transmitted to the control device 100.

  The control device 100 includes a unit recognizing unit (not shown) inside, and receives the detection information from the above-described sensors 22, 50 to 58, etc., and detects the unit where the sheet S is currently located. When a sheet S conveyed in each unit has a conveyance error, the control device 100 recognizes the unit to which the sheet S in which the conveyance error has occurred belongs, and also displays a message display 615 (LCD) on the operation panel 200. ) To indicate the optimal processing procedure.

  Next, a control system of the copying machine 1 configured as described above will be described in detail. FIG. 8 is a flowchart of a control task for controlling the sheet S feeding operation of the apparatus main body 3. First, when the copy start key 605 is turned on, a sheet feeding task for controlling conveyance of the sheet S is started (step S101). Then, a position count value Cc corresponding to the position where the sheet feeding cassette units 304 to 307 are arranged on the sheet conveying path is set to the position counter C of the sheet feeding task (step S102).

  The position counter C is a sheet position counter for recognizing the current position (the leading end position) of the sheet S on the sheet conveyance path in the apparatus main body 3, and sets the position of the registration roller 13 to “0” on the upstream side (sheet feeding). Side) has a negative value, and the downstream side (sheet discharge side) has a positive value. The position counter C is counted up by an encoder clock of an unillustrated main motor or an internal timer clock for driving a conveyance unit such as a conveyance roller arranged on a sheet conveyance path in the apparatus main body 3. Is calculated. In the position counter C counted up by the encoder clock, the count value Cc corresponding to the position where the sheet feeding cassette units 304 to 307 are arranged is from the position of the sheet feeding cassette units 304 to 307 to the registration roller 13. A value obtained by dividing the actual distance in the transport path by the moving distance per one pulse of the encoder clock is set. The position counter C is configured to indicate a value calculated in the same manner as in the setting method described above.

  Next, a value obtained by subtracting the position count value Cc corresponding to the arrangement position of the sheet feeding cassette units 304 to 307 from the count value Cp of the position counter C in the previous sheet feeding task control is fed on the sheet conveyance path. The process waits until the count value becomes greater than the count value Cb corresponding to the sheet interval distance between the preceding sheet and the succeeding sheet (step S103). If there is a request to feed the next sheet S, the next sheet feeding task is started (step S101), and if there is no request to feed the next sheet S, the sheet feeding task is ended.

  Next, a specific operation of the sheet feeding task will be described. FIG. 9 is a flowchart illustrating the operation of the sheet feeding task. First, when the sheet feeding task is started, it is checked whether the sheet S passes through any of the sensors 22 and 50 to 58 disposed on the conveyance path (step S201). After passing through any of the sensors 22, 50 to 58, the value of the position counter C is corrected (updated) to the absolute position counter value Ca corresponding to the arrangement position of the sensor 22, 50 to 58 (step S202). Further, the conveying means such as a conveying roller to be driven next, which is disposed on the sheet conveying path, is turned on, and the conveying means such as the conveying roller which has already passed is turned off (step S203).

  Next, the sensors 22, 50 to 58 check whether a jam has occurred in the sheet S being conveyed (step S204). When a jam occurs on the sheet conveyance path, the current value Cx of the position counter C is changed to the value of the fixing conveyance unit 301, the temporary storage tray unit 302, the re-feed conveyance unit 303, and the sheet feeding on the sheet conveyance path. It is calculated which of the units such as the feed cassette units 304 to 307, the manual feed cover unit 310, the upper right door unit 311 and the lower right door unit 312 belongs (step S205).

  The sheet stop position determining means provided in the control device 100 determines the optimum stop position of the sheet S based on the count information of the position counter C, and sets the optimum stop position for stopping the sheet S in the unit to which the sheet S belongs. The stop position count value Cs of the position counter C corresponding to the set position is output. Then, the current position count value Cx is subtracted from the stop position count value Cs (step S206), and the process waits until a difference position count value Cd corresponding to the difference elapses (step S207). Thereafter, the conveying means such as the conveying roller being driven is turned off by the stop control means to stop the sheet S at a predetermined stop position (step S208). After stopping the sheet S which is the cause of the conveyance abnormality, the stop control means also sequentially stops the sheets located on the sheet conveyance path upstream of the stopped sheet S in the sheet conveyance path.

  In other words, the sheet conveying apparatus according to the present embodiment recognizes the current position of the sheet by the position counter that indicates the absolute position of the sheet on the sheet conveying path when the sheet conveying abnormality is detected by the conveying error detecting unit, and stops the sheet. Position determining means determines an optimal stop position of the sheet. Then, the stop control means stops the sheet at the stop position determined by the sheet stop position determination means. Thereby, the sheet can be stopped at the optimal stop position.

  For example, the sheet S immediately before the registration roller 13 or the sheet S passing through the registration roller 13 is stopped with the vicinity of the rear end of the sheet SR sandwiched between the registration rollers 13 as shown in FIG. Since the rear end of the sheet SR is stopped at a position completely inside the fixing and conveying unit 301 shown by the broken line in FIG. 1, even if the fixing and conveying unit 301 is pulled out to the front, the sheet SR is not damaged. Further, since the sheet SR stops while being nipped by the registration rollers 13, when the fixing and transporting unit 301 is pulled out, the sheet SR is reliably pulled out together with the fixing and transporting unit 301, and is attracted to the photosensitive drum 7a to move to the main body side. Nothing remains. Further, since the vicinity of the rear end of the sheet SR is sandwiched by the registration rollers 13, it is easy to remove the sheet SR.

  Even if the sheet SR has the maximum length in the sheet conveyance direction among the sheets S used in the image forming apparatus, when the sheet SR stops at a predetermined stop position, the sheet SR By setting the distance between the registration roller 13 and the fixing rollers 16a and 16b so that the leading end is not pinched by the fixing rollers 16a and 16b, the removal of the sheet SR becomes easy. Even when the distance between the registration roller 13 and the fixing rollers 16a and 16b is relatively short, the fixing rollers 16a and 16b are stopped before the leading end of the sheet SR reaches the fixing rollers 16a and 16b. Is also good. In that case, when stopped at a predetermined stop position, the sheet SR curves between the fixing device 16 and the photosensitive drum 7a.

  Next, it is checked whether or not there is a succeeding sheet S upstream of the stopped sheet S (step S209). If there is a succeeding sheet S, the occurrence of a jam of the preceding sheet S is notified to the sheet feeding task of the succeeding sheet S (step S210). If there is no subsequent sheet S, it is checked whether or not the current position count value Cx has passed the count value Ci of the position counter C corresponding to the arrangement position of the separation charger 7g (step S211).

  When the current position count value Cx has passed the arrangement position count value Ci of the separation charger 7g, the charging is turned off in the order of primary charging, developing bias, post charging, transfer charging, and separation charging. The post-rotation control for the high pressure is started (step S212), the control is shifted to the next task, and the sheet feeding task ends. This task is activated for a certain period of time or as needed.

  Next, display control to be displayed on the operation panel 200 when a jam of the sheet S on the sheet conveyance path occurs will be described. FIG. 10 is a flowchart in controlling the jam display task. When a jam occurs in the sheet S conveyed on the sheet conveyance path, a jam display task is activated. First, the number n of sheets S remaining on the sheet conveyance path in the apparatus main body 3 (excluding the number of sheets S normally accommodated in the sheet feeding cassette units 304 to 307) is described above as the sheet feeding task. This is calculated from the information, and the number of sheet removal tasks Tn (n times) related to the jam processing is obtained (step S301).

  Then, the number Ui of each unit on the sheet conveyance path where each sheet S is stopped is calculated (step S302). The unit number Ui is determined by the first unit number and the second unit number for which the priority order of the jam processing has been determined, for example, when the sheet S is unavoidably stopped between adjacent units. Are assigned.

  For example, the sheet S stopped immediately before the registration roller 13 has the first unit number in which the jam processing for the upper right door unit 311 shown in FIG. 6 has the priority processing order, and the jam processing for the fixing and conveying unit 301 shown in FIG. Is the second unit number which is the post-processing order. That is, by instructing the operator to preferentially process the unit corresponding to the first unit number, the jammed sheet S can be efficiently and easily removed.

  Next, it is determined whether there is a unit Up to be removed with priority. This is because, if the sheet S of the priority unit Up is not removed first, there is damage to the sheet S to be removed, or the stop position of the sheet S or the like due to the jam cannot be accurately determined, or the sheet S is inevitably adjacent. This is advantageous when the sheet S is stopped between the units.

  First, "1" is set to a temporary variable i for counting the number n of sheets S to be removed remaining on the sheet conveyance path in the apparatus main body 3 (step S303). While judging that the temporary variable i reaches the number n to be removed (step S304), it is checked whether or not the priority unit Up is set in advance (step S305). If it is the priority unit Up, the priority unit Up existence flag is set (step S306), the temporary variable i is incremented (sequentially adding "1") (step S307), and the sheet is removed by the number of times Tn corresponding to the number n to be removed. Repeat the task. Then, if the above-mentioned priority unit Up presence flag is set (step S308), a sheet removal process described later is executed (step S309), and the sheets S to be removed with priority are sequentially removed.

  Next, the remaining sheet S is similarly subjected to the removing process. First, "1" is set to the temporary variable i (step S310). While determining that the temporary variable i reaches the number n to be removed (step S311), a sheet S removal process described later is executed (step S312), and the temporary variable i is incremented (sequentially adding "1") (step S313). ). When the sheet removing task is repeated Tn times corresponding to the number n of sheets to be removed, the sheet removing task control operation ends.

  Next, the sheet S removal processing will be described. FIG. 11 is a flowchart showing the control of the sheet removing process. The display order determination unit provided in the control device 100 determines the display order of the jam processing target unit recognized by the unit recognition unit described above, and the display control unit operates the display unit to display the jam on the message display 615. Is displayed.

  First, a message prompting the user to perform jam processing for the first unit number, which is the priority processing order, is displayed on the message display 615 (LCD) of the operation panel 200 (step S401), and the first unit is detached or opened and closed by the operator. Wait for the operation (step S402). When the first unit is attached or detached or opened and closed, the sensor provided in the first unit is in a state capable of detecting the sheet S, that is, the sensor is attached before the first unit is attached or detached or opened and closed. Detects whether the sheet S has been detected, and whether the sensor has been turned off due to attachment / detachment or opening / closing of the first unit (step S403).

  When the detection by the sensor is valid and the sensor is OFF, the operator removes the sheet S and recognizes that the removal of the sheet S is completed, and ends the control of the sheet removing process. In other states, that is, when the detection of the sensor is not valid or the sensor is ON, it is recognized that the removal of the sheet S is not completed. In this case, in step S404, it is checked whether or not the second unit number as the post-processing order is set (step S404). If the second unit number is not set, the detection of the sensor is performed. Is determined (step S405), and if the detection by the sensor is valid, the CPU waits for the first unit to be detached or opened or closed again (step S402).

  If the second unit number has been set, a message prompting the processing of the second unit number is displayed on the message display 615 of the operation panel 200 (step S406), and the second unit is detached by the operator. Or, it waits for opening and closing (step S407). When the second unit is detached or opened / closed, it is checked whether a sensor in the second unit is detecting the sheet S and whether the sensor is turned off by detaching / opening / closing the second unit. (Step S408).

  If the sensor is capable of detecting the sheet S and the sensor is OFF, it is recognized that the removal of the sheet S has been completed, and the control of the sheet removal process ends as described above. In other states, that is, when the detection of the sensor is not valid or / and the sensor is ON, it is recognized that the removal of the sheet S is not completed. In this case, in step S409, it is determined whether or not the detection of the sensor is valid. If the detection of the sensor is not valid, it is recognized that the removal of the sheet S is completed, and the control of the sheet removal process is performed. To end. If the detection by the sensor is valid, the process waits for the second unit to be detached or opened or closed again (step S407).

  Next, a jam post-processing task control for reusing the sheet S remaining in the temporary storage tray 23 when a jam occurs will be described. FIG. 12 is a flowchart of the post-jam processing. If it is recognized by the unit recognition means that the sheet S remains in the temporary storage tray 23, the display control means provided in the control device 100 operates the display means to display the message S on the message display 615. Is displayed to process the sheet S in the temporary storage tray 23.

  First, it is checked whether or not the sheet S remains in the temporary storage tray 23 (step S501). If the sheet S does not remain in the temporary storage tray 23, normal recovery data is calculated (step S506). I do.

  If the sheet S remains in the temporary storage tray 23, it is checked whether or not the temporary storage tray 23 has been detached after all the jams have been cleared (step S502). If the temporary storage tray 23 has been detached, the processing of the temporary storage tray 23 is displayed (step S503), and the process waits for the temporary storage tray 23 to be detached by the operator (step S504). After the temporary storage tray 23 is detached and attached, the process display is repeated until the sheets S in the temporary storage tray 23 are exhausted (step S505), and when the sheets S are exhausted in the temporary storage tray 23, the recovery data is calculated (step S506). ), The jam post-processing task control operation ends. If the operator detaches the temporary storage tray 23 even though the sheets S in the temporary storage tray 23 can be reused, the processing is displayed as reusable.

  Next, the control of the monitoring unit that monitors the occurrence of a jam, particularly the control when the copy operation is in the streaming mode, will be described. FIG. 13 is a flowchart of the jam monitoring control. First, the process waits until the copy start key 605 is pressed (step S601). When the copy start key 605 is pressed, it is determined from the document size, the copy magnification, and the like whether or not the flow reading operation is possible (step S602).

  If the flow reading operation is possible, the flow reading mode flag is set (step S603). If the drift reading mode flag is set (step S604), the occurrence of a jam in the circulating automatic document feeder 2 (RDF) is monitored by a detection unit (not shown) (step S605). If a jam has occurred in the automatic document feeder 2, the sheet feeding task during image formation is notified that the jam has occurred (step S606). The monitoring is continued until the copying is completed (step S607), and when the copying is completed, the monitoring unit ends the monitoring operation of the occurrence of the jam.

  That is, when a jam occurs in the automatic document feeder 2 in the flow-reading mode, the jamming of the sheet S on which an image is being formed corresponding to this document is forcibly stopped, so that the image formation is not completed. The sheet S can be prevented from being discharged outside the apparatus.

  INDUSTRIAL APPLICATION This invention can be utilized for the image forming apparatus which conveys a sheet and forms an image.

FIG. 1 is a schematic configuration diagram of a copying machine including a sheet conveying device. FIG. 2 is a block diagram of a control device of a copying machine having a sheet conveying device. FIG. 3 is a diagram illustrating an arrangement configuration of an operation panel. FIG. 9 is an explanatory diagram of an original reading operation by drift reading. FIG. 2 is a perspective view showing a detachable unit and an openable unit provided in the apparatus main body. It is a perspective view showing the open state of the upper right door unit. FIG. 4 is a perspective view illustrating a state in which the fixing and conveying unit is pulled out to the front and detached from the apparatus main body. 9 is a flowchart illustrating control of a sheet feeding operation task. 9 is a flowchart illustrating control of a sheet feeding task. It is a flowchart which shows control of a jam display task. 9 is a flowchart illustrating control of a sheet removing process. It is a flowchart which shows control of a jam post-processing task. It is a flowchart which shows the control of jam monitoring.

Explanation of reference numerals

A1 discharge path A2 re-transport path C position counter D document S sheet 1 copy machine 2 automatic document feeder 3 image forming apparatus main body 4 document reading section 7 image forming section 9 feeding cassette
13… Registration roller
16… Fusing unit
22… Emission sensor
23… Temporary storage tray
34… Refeeding device
50-58… Sensor
100 ... control unit
200… Operation panel
301… Fixing conveyance unit
302… Temporary storage tray unit
303… Re-feed unit
304-307… Sheet feeding cassette unit
310… Manual cover unit
311… Top right door unit
312… lower right door unit
615… Message display

Claims (7)

Sheet conveying means arranged in the sheet conveying path,
Sheet detection means for detecting passage of a sheet in the sheet conveyance path,
Conveyance abnormality detection means for detecting sheet conveyance abnormality in the sheet conveyance path,
A sheet position counter for recognizing the position of the sheet in the sheet transport path;
A sheet stop position determining unit that determines an optimal stop position of the sheet by the sheet position counter when a sheet transport abnormality is detected by the transport abnormality detecting unit;
Stop control means for stopping the sheet at the stop position determined by the sheet stop position determination means,
A sheet conveying device comprising: The method according to claim 1, wherein the stop control unit sequentially stops the sheets located upstream of the stopped sheet in the sheet conveyance direction in the sheet conveyance path after stopping the sheet causing the conveyance error. Item 2. The sheet conveying device according to Item 1. The sheet conveying device according to claim 1, wherein the sheet position counter recognizes a leading edge position of the sheet. 4. The sheet conveying device according to claim 1, wherein the sheet position counter updates the count value to a predetermined count when the sheet passes through the sheet detection unit. 5. Equipped with a plurality of detachable or openable and closable units that constitute the sheet transport path,
When a sheet conveyance error is detected by the conveyance error detection means, a unit belonging to the plurality of units is calculated based on counter information of the sheet position counter, and a count of the sheet position counter is calculated. The sheet conveying apparatus according to any one of claims 1 to 4, wherein the sheet stop position determining means determines an optimum stop position in a unit to which the sheet belongs based on the information. A count value corresponding to a difference between a stop position count value corresponding to a preset position and a current position count value from the sheet position counter, which is optimal for stopping the sheet in the unit to which the sheet belongs, has elapsed. 6. The sheet conveying apparatus according to claim 5, wherein the stop control means controls the sheet to stop after a while. The sheet conveying apparatus according to claim 1, wherein the sheet position counter counts using an encoder clock or an internal timer clock of a motor that drives the sheet conveying unit.

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