JP2011145558A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an operator a chance of shortening return time from interruption of image forming operation to restarting when jamming occurs. <P>SOLUTION: A determination means, upon discriminating that remaining paper exists on a conveyance path with a remaining-paper discriminating means, determines whether a position of remaining paper is such a position that the remaining paper can or cannot be automatically discharged by operating a conveyance means. When it is determined that the remaining paper can be automatically discharged, further, the determination means determines whether the position of the remaining paper is such a position as to shorten interruption time of image formation of an image forming apparatus by operator's manual removal rather than implementation of automatic paper discharge. When the position is determined to be such a position as to shorten interruption time by manual removal much more even when automatic paper discharge is available, a control means outputs a message of urging the operator to conduct manual removal. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an image forming apparatus.

  In the image forming apparatus, jamming rarely occurs in the sheet conveyance path. A jam is a phenomenon in which the conveyance of a sheet fails and the sheet is jammed in the conveyance path. Therefore, the jammed paper (jam paper) must be removed by the operator. This removal processing is called jam processing. Generally, an image forming apparatus has a function of detecting the occurrence of a jam. Note that another sheet may remain in the conveyance path even after the jam processing is executed. Such paper will be called residual paper. In an image forming apparatus having a residual paper detection function, it is determined whether or not the residual paper can be automatically discharged. The image forming apparatus automatically discharges the residual paper by the transport roller if automatic discharge is possible, and notifies the operator of a message for manually removing the residual paper if automatic discharge is not possible. According to Patent Document 1, it is detected whether there is a sheet in a section surely before the flapper, a section that passes through the flapper, or a section that does not pass through the flapper reliably, and automatic paper discharge is performed. An invention for appropriately determining whether it is possible or impossible has been proposed.

JP 2002-154744 A

  In the conventional image forming apparatus, when it is determined that the remaining sheet can be automatically discharged, automatic discharge is always performed. However, depending on the position of the remaining paper on the conveyance path, the time required for manual paper discharge may be shorter than the time required for automatic paper discharge. This means that the return time from the stop to the restart of the image forming operation may be shortened. Therefore, an object of the present invention is to solve at least one of such problems and other problems. For example, an object of the present invention is to provide an operator with an opportunity to shorten the return time from the stop to the restart of an image forming operation when a jam occurs. Other issues can be understood throughout the specification.

  The image forming apparatus is provided at a different position in the conveyance path, and detects a position of the paper, a conveyance unit that conveys the sheet in the conveyance path, a jam detection unit that detects that a paper jam has occurred in the conveyance path, and Position detecting means. Further, the image forming apparatus includes a remaining sheet determining unit, a determining unit, and a control unit. The residual paper discriminating means detects the presence of residual paper and the residual paper by detecting the position of the paper remaining in the transport path by the position detecting means when the removal of the paper detected as jam by the jam detecting means is completed. Determine the position of. If the determination unit determines that the remaining sheet is present in the conveyance path by the remaining sheet determination unit, it is possible to shorten the image formation interruption time of the image forming apparatus when the position of the remaining sheet is automatically discharged by the conveyance unit. It is determined whether it is a position or a position where manual removal can shorten the interruption time. The control means outputs a message urging manual removal when the judgment means judges that the manual removal of the position of the remaining paper is a position where the interruption time can be shortened even if the paper can be automatically discharged. On the other hand, when the determination unit determines that the position where the remaining paper is automatically discharged is a position where the interruption time can be shortened rather than the manual removal, the control unit controls the conveying unit to automatically discharge the remaining paper.

  As described above, according to the present invention, even if the remaining paper can be automatically discharged, if the operator manually removes the remaining paper earlier, the operator is prompted to perform manual removal. Therefore, it is possible to give the operator an opportunity to reduce the return time from the stop to the restart of the image forming operation when a jam occurs. This will further improve the convenience for the operator.

1 is a cross-sectional view illustrating a configuration of an image forming apparatus 1 according to an embodiment. It is a figure which shows the hardware structural example centering on a control part. It is a figure which shows arrangement | positioning of the sensors 101-110 in a conveyance path, and the conveyance state of a paper. 6 is a flowchart illustrating a remaining paper discharge process according to the embodiment. (A) shows a manual removal mode, and (B) is a flowchart showing an automatic paper discharge mode. It is a flowchart which shows a user removable mode. 6 is a flowchart illustrating a remaining paper discharge process according to the embodiment.

  In the present invention, when the jam occurs, the operator removes the jammed paper. In general, paper other than the jammed paper may remain in the transport path. Residual paper can be automatically discharged. Depending on where the residual paper is located in the conveyance path, automatic paper discharge can be removed faster and manual removal can be removed faster. Therefore, in the present invention, it is determined whether the position of the remaining paper is a position where the conveying means is operated and the remaining paper can be automatically discharged, or whether the remaining paper cannot be automatically discharged. To do. If it is possible to automatically discharge the remaining paper, it is further determined whether the position where the residual paper is manually removed by the operator can shorten the interruption time of image formation of the image forming apparatus rather than executing the automatic paper discharge. judge. Even if automatic paper discharge is possible, if there is residual paper at a position where the manual removal can shorten the interruption time, the operator is notified of a message prompting manual removal. In the following, a specific example will be described for determining whether or not the position of the remaining paper is a position where manual removal by the operator can shorten the image formation interruption time rather than executing automatic paper discharge.

<< First Embodiment >>
As shown in FIG. 1, the image forming apparatus 1 includes a paper feeding unit 20, an image forming unit 30, and a paper discharge unit 40. In the present invention, since there is a characteristic in the processing of residual paper, it does not depend on the image forming method. Here, for the sake of convenience, an electrophotographic image forming apparatus will be described, but any image forming apparatus of an electrostatic recording system, a magnetic recording system, an ink jet system, a sublimation system, or an offset printing system may be used.

  The paper feed unit 20 includes a paper feed cassette 21 and a multi-tray 24. The paper is fed from the paper feed cassette 21 by the pickup paper feed roller 22, and the paper is transported by the transport roller 23. From the multi-tray 24 which is a kind of manual tray, the multi-pickup paper feed roller 25 feeds the paper, and the multi-transport roller 26 transports the paper. The paper fed from the paper feed cassette 21 and the multi-tray 24 is transported to the image forming unit 30 via the transport path. The image forming unit 30 includes an exposure device 31, a photosensitive drum 32, a developing device 33, a transfer belt 34, a secondary transfer roller 36, a fixing device 37, and a cleaner 38. Y, M, C, and K given to the end of the reference code indicate four colors of yellow, magenta, cyan, and black. It should be noted that YMCK is omitted when describing matters common to each toner color. The exposure device 31 exposes the photosensitive drum 32 by irradiating laser light based on image data via a polyhedral mirror, thereby forming an electrostatic latent image. Instead of a laser, a light emitting element such as an LED can be used. The photosensitive drum 32 is a kind of image carrier and is charged with a constant charge on the surface. Light is irradiated from the exposure device 31 to the charged photosensitive drum 32. The developing device 33 charges the toner and adheres to the surface of the photosensitive drum 32 to form a visible image. The transfer belt 34 is disposed on the loop in contact with the photosensitive drum 32 below the photosensitive drum 32, and rotates so as to contact in the order of 32Y, 32M, 32C, and 32K. A transfer roller 35 is disposed inside the transfer belt 34. The transfer roller 35 is charged with a certain amount of charge, and visible images formed on the surface of the photosensitive drum 32 are transferred in the order of 32Y, 32M, 32C, and 32K. Transcript to. The transfer belt 34 continues to rotate, and the transferred toner is transferred to the paper by the secondary transfer roller 36. The fixing device 37 includes a heating roller and a pressure roller, and fuses the toner to the paper by heat and pressure to make the image transferred to the paper a permanent image. The cleaner 38 removes the toner remaining on the surface of the photosensitive drum 32 after the transfer is completed. The paper discharge unit 40 includes paper discharge transport rollers 41 and 42, and the paper on which the permanent image is drawn by the image forming unit 30 is transported to the paper discharge port 45 by the transport rollers 41 and 42. When performing double-sided printing, the double-side flapper 43 guides the paper from the main transport path to the auxiliary transport path. A reversing mechanism is provided in the auxiliary transport path. The sheet guided to the reversing mechanism is pulled by the reversing roller 44, and a part of the sheet is exposed to the outside of the image forming apparatus 1. When the drawing is completed, the reversing roller 44 is rotated in the reverse direction to convey the paper in the reverse direction and guided to the double-sided conveyance unit that is a part of the auxiliary conveyance path. The paper guided to the double-sided conveyance unit is conveyed again by the image forming unit 30 by the conveyance rollers 46, 47, and 48, passes through the secondary transfer roller 36 and the fixing device 37, and is discharged by the conveyance rollers 41 and 42. It is conveyed to 45.

  In FIG. 2, a CPU 201 is a control unit that comprehensively controls each unit of the image forming apparatus 1. The CPU 201 includes a residual paper determination unit 205 and a paper removal determination unit 206 that are realized only by hardware or by hardware or software. A display control unit 202, a drive unit 204, a sensor unit 100, and a nonvolatile memory 207 are connected to the CPU 201. The sensor unit 100 includes sensors 101 to 110 for detecting the presence / absence of a sheet disposed in the conveyance path and the position of the sheet. Each of the sensors 101 to 110 is provided at a different position in the conveyance path, detects whether or not the sheet is passing through the position, and outputs the detection result to the CPU 201. That is, the sensors 101 to 110 notify the CPU 201 that there is a sheet if the sheet has passed, and notify the CPU 201 that there is no sheet if the sheet has not passed. CPU201, since knows whether advance which sensor is set to any position in the transport path, to recognize whether there paper from which sensor has been notified, or where the paper conveyance path is located Can be determined. Further, the CPU 201 outputs drive data to the drive unit 204 based on the detection signal input from the sensor unit 100. In addition, the state of each sensor is output to the display control unit 202. The drive unit 204 controls each drive part of the paper feed unit 20, the image forming unit 30, and the paper discharge unit 40 based on the drive data input from the CPU 201. The display control unit 202 is connected to the CPU 201 by a serial communication line and a signal line, and is connected to a display unit 203 having a display. The display unit 203 functions as a notification unit that notifies the operator of a message prompting manual removal when the first determination unit determines that the position of the remaining paper matches the position where automatic paper discharge is not possible. Similarly, when the second determination unit determines that the manual removal of the position of the remaining paper matches the position where the interruption time can be shortened even if the second paper can be automatically discharged, the display unit 203 performs the manual removal to the operator. It functions as a notification means for notifying a prompt message. The display control unit 202 requests the state of each sensor from the CPU 201, and notifies the display unit 203 of the content to be displayed on the display according to the state of each sensor input from the CPU 201. Display unit 203 displays information received from display control unit 202 on a display.

  The residual paper determination unit 205 provided in the CPU 201 has a known jam detection function in addition to the residual paper determination function. The remaining paper determination unit 205 stores the paper position at the time of occurrence of the jam and the paper after the jam processing in the nonvolatile memory 207, and specifies the presence / absence of the residual paper and the position of the residual paper. The paper removal determination unit 206 determines whether automatic paper discharge is possible or not based on the position of the remaining paper read from the nonvolatile memory 207. When it is determined that automatic paper discharge is possible, the paper removal determination unit 206 further determines whether it is faster for the operator to remove the remaining paper or to automatically discharge the paper.

  If the paper removal determination unit 206 determines that automatic discharge of residual paper is impossible, the CPU 201 notifies the display unit 203 via the display control unit 202 so as to notify the operator of a message prompting manual removal of the residual paper. Command. Even when the paper removal determination unit 206 determines that it is possible to automatically discharge the remaining paper and it is faster for the operator to remove the remaining paper, the CPU 201 issues a message prompting the operator to manually remove the remaining paper. The display unit 203 is instructed via the display control unit 202 to notify. When it is determined that it is faster to automatically discharge the remaining paper, the CPU 201 instructs the display unit 203 via the display control unit 202 to notify that automatic paper discharge is in progress.

  3A and 3B show the arrangement of the sensors 101 to 110 and the positions 301 to 311 of a plurality of remaining sheets remaining on the conveyance path after the jam processing. According to FIG. 3A, the paper fed from the paper feed cassette 21 is transported so as to pass through the sensors 102, 103, 104, 105, and 106 in order, and is discharged at the end of the transport path. The paper is discharged to the mouth 45. The paper fed from the multi-tray 24 is conveyed so as to pass through the sensors 101, 103, 104, 105, and 106 in this order, and is discharged to the paper discharge port 45. The sheet designated for duplex printing passes through the sensor 105, passes through the reverse roller 44 in the order of 108, 109, 110, and is conveyed so as to pass through the sensor 103 again.

  The remaining paper determination unit 205 stores, in the nonvolatile memory 207, the positions of the paper to be jammed and all other papers in the machine depending on the state of the sensors 101 to 110 when the jam occurs. If the job forms an image on only one sheet, the sheet is easily detected as a jam target. On the other hand, in the case of a job for forming an image on a plurality of sheets, the sheets are generally conveyed at equal intervals. Each sheet passes through the position of each sensor at a constant timing (cycle). Therefore, if the sensor does not detect a sheet even at a predetermined timing, the remaining sheet determination unit 205 can detect that the sheet is jammed.

  During the printing operation, the sensors 101 to 110 are turned from the OFF state to the ON state when the leading edge of the paper is approaching, are kept on while the paper is passing the sensor, and are turned from the ON state to the OFF state after the trailing edge of the paper has passed the sensor. become. Depending on the sensor, ON and OFF may be reversed. If the sensor is in an ON state when a jam occurs and the printing operation is stopped, the remaining paper determination unit 205 starts from the time when the leading edge of the paper reaches the sensor (when it is turned ON) until the occurrence of the jam. From the elapsed time and the sheet conveyance speed, the leading end position of the sheet can be calculated based on the sensor. Further, the trailing edge position of the paper can be calculated from the paper size. The remaining sheet determination unit 205 stores the position of each sheet identified in this way in the nonvolatile memory 207 as sheet position information when a jam occurs. After the trailing edge of the paper passes the sensor, a jam may occur and the printing operation may stop before the next sensor detects the leading edge of the paper in the paper conveyance direction. In this case, the remaining sheet determination unit 205 determines that there is a sheet between the sensors, calculates the position of the sheet by the same calculation procedure, and stores it in the nonvolatile memory 207 as sheet position information when a jam occurs.

  If the sensor is in the ON state after the jam processing, the remaining paper determination unit 205 calculates the position of each paper in the same manner and stores it in the nonvolatile memory 207 as the paper position information after the jam processing. When the paper position stored after the jam processing is the same as the paper position of the jam target paper stored when the jam occurs, the remaining paper determination unit 205 determines that the jam target paper has not been removed. Further, when a sheet is detected at a position different from the position of the jam target sheet, the remaining sheet determination unit 205 determines that the remaining sheet exists at that position. The remaining sheet determination unit 205 stores the position of the remaining sheet in the nonvolatile memory 207. In the embodiment of the present invention, the non-volatile memory 207 is adopted so that the remaining paper can be properly removed even when the operator turns the power OFF / ON during the jam processing. If the power is not turned off / on, the nonvolatile memory 207 may be replaced with the RAM of the CPU 201.

  An example of a processing procedure related to the first embodiment will be described with reference to FIG. In this flowchart, the time when the operator closes the door of the image forming apparatus 1 opened for jam processing after jam processing is set as the start time. That is, the CPU 201 detects that a paper jam has occurred in the conveyance path from the detection results of the sensors output from the sensor unit 100. Since a method for detecting a jam is publicly known, it is omitted here. The CPU 201 outputs a message prompting the operator to remove the jammed paper on the display unit 203 via the display control unit 202. An operator opens the door of the image forming apparatus 1 to remove the jam target paper, and detects that the door is closed after the jam processing by a door opening / closing detection sensor (not shown).

  In step S <b> 401, the remaining sheet determination unit 205 acquires the position of the remaining sheet from the nonvolatile memory 207. In step S <b> 402, the residual paper determination unit 205 determines whether there is residual paper in the conveyance path of the image forming apparatus 1. The remaining paper determination unit 205 recognizes the presence and position of each sheet in the transport path at that time from the detection result from the sensor unit 100. The remaining sheet determination unit 205 compares the position of each sheet at the time of jam detection with the position of each sheet after the manual removal of the jam target sheet. For example, if the comparison result indicates that there is no sheet on the conveyance path after the manual removal of the jam target sheet, the remaining sheet determination unit 205 determines that there is no remaining sheet. If it is determined that there is no remaining paper, the CPU 201 returns to the normal printing operation. On the other hand, if the comparison result indicates that there is residual paper at any position, the residual paper determination unit 205 determines that there is residual paper at that position, and proceeds to step S403. As described above, the residual paper determination unit 205 detects the position of the paper remaining in the conveyance path by the position detection unit when the removal of the paper detected as jam by the jam detection unit is completed. It functions as a residual paper discriminating means for discriminating the presence or absence and the position of the residual paper.

  In step S <b> 403, the paper removal determination unit 206 determines whether the remaining paper can be automatically discharged or not according to the position of the remaining paper. When the residual paper determination unit 206 determines that the residual paper exists in the conveyance path, the paper removal determination unit 206 sets the residual paper to a position where the residual paper can be automatically discharged when the conveyance unit is operated. It functions as a first determination unit that determines whether they coincide with each other or whether the sheet coincides with a position where automatic discharge of the remaining paper is impossible even if the conveying unit is operated. For example, if the position of the jam target paper at the time of jam occurrence is the position 302 shown in FIG. 3 and the position after the jam processing is also the position 302, the paper removal determination unit 206 determines that the jam target paper has not been removed. Judge that there is. The jam target paper is jammed because it cannot be discharged even if the conveyance roller is driven via the driving unit 204. Therefore, the paper removal determination unit 206 determines that automatic paper discharge is impossible (manual removal is necessary) if the jam target paper is not removed. On the other hand, it is assumed that the position of the jam target paper at the time of jam occurrence is the position 302 and the position of the other paper is the position approaching the fixing device 37 as the position 304. Further, if the position of the remaining paper detected after the jam processing is the position 304, the paper removal determination unit 206 determines that automatic paper discharge is impossible. When the printing operation is stopped, the fixing temperature of the fixing device 37 is usually lower than the fixing temperature. Therefore, if the automatic paper discharge is started as it is, the unfixed toner image existing on the paper cannot be fixed correctly. This unfixed toner may contaminate not only the fixing device 37 but also a device existing downstream in the transport direction from the fixing device 37. For this reason, even when the remaining sheet is in a position where it has reached the fixing device 37 as in the position 304, the sheet removal determination unit 206 determines that automatic paper discharge is impossible. Assume that the position of the jam target paper at the time of jam occurrence is the position 302 and the position of the other paper is the position 305. The sheet at position 305 is the sheet that has just reached the double-sided flapper 43. If the position of the remaining paper after the jam processing is the position 305, it is highly possible that the paper is jammed if automatic paper ejection is performed as it is. Therefore, even when a residual paper is detected at the position 305, the paper removal determination unit 206 determines that automatic paper discharge is impossible. Even at other positions, there are positions where automatic paper discharge is impossible depending on the configuration of the image forming apparatus. As described above, information indicating the position where automatic paper discharge is not possible (the detection result of the sensor unit 100) is stored in the nonvolatile memory 207 in advance. If it is determined that automatic paper discharge is impossible, the process proceeds to S10.

  In step S410, the CPU 201 processes the remaining paper according to the manual removal mode. Details of S410 are shown in FIG. In step S411, the CPU 201 sets the residual paper removal mode to the manual removal mode. In step S <b> 412, the CPU 201 displays a message prompting the operator to manually remove the remaining paper and the position of the remaining paper on the display unit 203 via the display control unit 202. In step S413, the residual paper determination unit 205 determines whether the operator has removed the residual paper. Whether or not the residual paper has been removed is the same as the detection method of the presence and position of the residual paper in S402. For example, the state of the sensor 104 corresponding to the remaining paper is the ON state. Therefore, the residual paper determination unit 205 determines that the operator has removed the residual paper when the sensor 104 is turned off, and ends the manual removal mode. A configuration may be employed in which the CPU 201 recognizes the removal by providing a removal end button or the like and pressing the button after the operator removes the remaining paper.

  An example in which it is possible to determine in step S403 that automatic paper discharge is possible is as follows. Assume that the position of the jam target paper is the position 302 and the position of the other paper is the position 301 when the jam occurs. The sheet present at the position 301 is a sheet fed from the multi-tray 24 and approaching the sensor 101. Further, the sheet present at the position 306 is a sheet that has been guided to the double-sided conveyance unit by the reversing roller 44 and has reached the sensor 108. After the jam target paper existing at the position 302 is jammed, if there is residual paper at the position 301 or the position 306, the paper can be automatically discharged in either case. Therefore, when residual paper is detected at these positions, the paper removal determination unit 206 determines that automatic paper discharge is possible. Thereafter, the process proceeds to S404.

  In step S <b> 404, the paper removal determination unit 206 determines whether the remaining paper stop position is earlier when the drive unit 204 is controlled and the remaining paper is automatically discharged by the conveyance roller, or when the operator manually removes it. judge. That is, the focus of determination is which one can shorten the interruption time of image formation of the image forming apparatus. When the first determination unit determines that the position of the remaining sheet coincides with a position where automatic discharge is possible, the sheet removal determination unit 206 determines that the image forming apparatus performs image formation when the remaining sheet is automatically discharged. It functions as a second determination means for determining whether it matches the position where the interruption time can be shortened or whether the manual removal matches the position where the interruption time can be shortened.

  The non-volatile memory 207 stores information indicating whether the automatic paper discharge is a position where the interruption time can be shortened or the manual removal is a position where the interruption time can be shortened for each position of the remaining paper assumed in advance. It may function as storage means. In other words, at the time of factory shipment, it is determined whether each of a plurality of positions on the transport path should be automatically discharged or manually removed, and the discharge method for each position is associated and stored in the nonvolatile memory 207. Keep it. The paper removal determination unit 206 compares the position of the residual paper specified by the residual paper determination unit 205 with the information stored in the nonvolatile memory 207. Thus, it is determined whether automatic discharge is a position where the interruption time can be shortened or manual removal is a position where the interruption time can be shortened. As a result, if the manual removal processing time is longer than the automatic paper discharge time, the paper removal determination unit 206 determines that the position of the remaining paper is a position where the automatic paper discharge can shorten the interruption time. On the other hand, if the manual removal processing time is not longer than the automatic paper discharge time, the paper removal determination unit 206 determines that the position of the remaining paper is a position where the interruption time can be shortened by manual removal.

  In the first embodiment, information on whether automatic paper discharge should be manually discharged or manually removed is stored in the nonvolatile memory 207 for each position on the transport path, and this information is referred to based on the position of the remaining paper. It is determined which of the paper discharge methods can shorten the interruption time. As described in the second embodiment, the automatic paper discharge time and the manual removal time may be dynamically calculated and compared.

  By the way, in the automatic paper discharge, a time (automatic paper discharge time) obtained by adding a margin of several seconds to several tens of seconds to the maximum transport time required when the remaining paper located farthest from the paper discharge port 45 is transported to the paper discharge port 45. ). If the automatic paper discharge is performed over the automatic paper discharge time, the CPU 201 determines that the automatic paper discharge is completed. This time is measured by a timer or a counter. In the embodiment, the position farthest from the sheet discharge outlet 45 among the positions where the remaining sheet can exist is the position 306. This maximum transfer time varies depending on the model. Further, the maximum conveyance time when the optional paper feed cassette is installed in the image forming apparatus 1 is longer than that when the optional paper feed cassette is not installed. Therefore, the nonvolatile memory 207 stores the maximum conveyance time of the own model and the respective maximum conveyance times when each option is installed, and the CPU 201 can acquire the maximum conveyance time from the nonvolatile memory 207. It should be noted that data on the transport speed and the distance from each position on the transport path to the paper discharge outlet 45 may be stored in the nonvolatile memory 207, and the CPU 201 may calculate the maximum transport time from these data. The CPU 201 may further consider the paper size (length in the transport direction). The CPU 201 may add the size of the paper to the distance from the position where the residual paper is detected to the paper discharge port 45, and further calculate the distance from the position to the trailing edge of the residual paper and discharge this. You may add to the distance to the mouth 45. In the embodiment of the present invention, for convenience, the time from the automatic paper discharge until the paper discharge is completed is set to 20 seconds, for example.

  In the position 301 or the position 306 illustrated in FIG. 3, a part of the remaining paper may be exposed to the outside of the image forming apparatus 1. The residual paper present at the position 301 is paper fed from the multi-tray 24 that is a manual feed tray for manually feeding paper, and a part thereof is exposed to the outside of the image forming apparatus 1. A position 306 is an auxiliary conveyance path for reversing the sheet on which the image is formed on the first side in order to form an image on the second side of the sheet on which the image is formed on the first side, and feeding it again to the image forming unit. Is part of. At this position 306, when the residual paper is fed through the auxiliary conveyance path, a part of the residual paper is exposed to the outside of the image forming apparatus. In these cases, the operator can pull out the remaining paper. Moreover, the time required for removal will be, for example, 1 second to 2 seconds. Therefore, if there is residual paper at the position 301 or 306, the paper removal determination unit 206 determines that the residual paper can be removed earlier by manual removal than by automatic paper discharge. As described above, when the position of the remaining sheet is a position where a part of the remaining sheet is exposed to the outside of the image forming apparatus, the sheet removal determination unit 206 manually removes the sheet by the operator rather than executing the automatic sheet discharge. It is determined that the interruption time can be shortened. If it is determined that it is faster for the operator to remove manually, the process proceeds to S420.

  In step S420, the CPU 201 executes residual paper removal processing according to the user-removable mode. In this way, the CPU 201 determines that the first determination unit matches the position of the remaining sheet with a position where automatic discharge is possible, and the second determination unit automatically discharges the position of the remaining sheet more than manual removal. If it is determined that the position coincides with the position where the interruption time can be shortened, it functions as a control means for controlling the conveying means to automatically discharge the remaining paper.

  The user-removable mode will be described with reference to FIG. In step S <b> 601, the CPU 201 sets the residual paper removal mode to the user removable mode. In step S <b> 602, the CPU 201 displays a message that prompts the operator to remove the remaining paper on the display unit 203. In step S <b> 603, the CPU 201 starts measuring time using a timer from the start of display, and determines whether the measured time has elapsed a predetermined time t <b> 1. The timer determines the elapsed time after the notification means notifies the operator of a message for manual removal by determining that the second determination means manually removes the position of the remaining paper so that the interruption time can be shortened. It is an example of the time measuring means to time. If t1 has not elapsed, the process proceeds to S604. In step S604, the CPU 201 determines whether the residual paper has been removed by the operator or not. The determination method in S604 is the same as that in S413 described above. If it is determined that it has been removed by the operator, the CPU 201 deletes the message and ends the user-removable mode process. If not removed by the operator, the process returns to S602. On the other hand, when the predetermined time t1 elapses without the residual paper being removed by the operator, the process proceeds to S430, and the CPU 201 executes the residual paper removal process according to the automatic paper discharge mode. As described above, the CPU 201 functions as a control unit that controls the conveying unit to automatically discharge the remaining paper when the elapsed time counted by the timing unit exceeds a predetermined threshold. A specific example of the automatic paper discharge mode is as shown in S431 to S434 of FIG. In the embodiment, t1 is defined as 10 seconds, for example.

  Conventionally, when automatic paper discharge is performed to remove the residual paper, it takes about 20 seconds. However, according to the present invention, the average value of the residual paper removal time can be shortened. For example, when there is residual paper at the position 301 or the position 306, the removal time can be shortened to 1 second to 2 seconds by the user removable mode. If manual removal is not performed even when the user removable mode is set, automatic discharge can be performed by providing a timeout time of 10 seconds. That is, it is possible to return to the printing operation in 30 seconds in total. That is, an operator who feels that manual removal is troublesome can omit the explicit switching instruction to the automatic paper discharge mode and execute the automatic paper discharge mode.

  By the way, in positions other than the position 301 and the position 306, a part of the remaining paper is not exposed to the outside of the apparatus, so that the operator cannot easily remove the residual paper. In addition, at the position 304 and the position 305, automatic paper discharge is not recommended for the reasons described above. Therefore, if there is residual paper at these positions, the paper removal determination unit 206 determines that the automatic paper discharge can discharge the residual paper earlier than manual removal. In this case, the process proceeds to S430.

  In step S430, the CPU 201 executes residual paper removal according to the automatic paper discharge mode. An example of the automatic paper discharge mode will be described with reference to FIG. In step S431, the CPU 201 sets the residual paper removal mode to the automatic paper discharge mode. In step S432, the CPU 201 instructs the driving unit 204 to start automatic discharge of the remaining paper. The drive unit 204 activates a motor for driving the transport roller in accordance with this command. In step S433, the CPU 201 displays on the display unit 203 that automatic paper discharge is in progress. In step S434, the residual paper determination unit 205 determines whether the automatic paper discharge has been completed according to whether the detection result from each sensor from the sensor unit 100 indicates that all residual paper has been discharged or assimilation. If automatic paper discharge has not been completed, the process returns to S433. If it is determined that the automatic paper discharge has been completed, the CPU 201 deletes the message and ends the automatic paper discharge mode.

  According to the present exemplary embodiment, even when the position of the remaining paper is a position where automatic paper discharge is possible, the manual image removal by the operator is shorter than the execution of automatic paper discharge, so that the image formation interruption time of the image forming apparatus is shortened. If it is possible, the operator can be given an opportunity for manual removal. That is, since the operator can be given an opportunity to shorten the time from the stop of the image forming operation to the return to the image forming operation, the convenience in use can be improved. Further, even if the mode is shifted to the user removable mode, if the manual removal is not executed before the predetermined time t1 elapses, automatic paper discharge is executed. Therefore, there is an advantage that an operator who still desires automatic paper discharge can omit the user-removable mode release or the switching instruction to the automatic paper discharge mode.

<< Second Embodiment >>
In the first embodiment, automatic paper discharge or manual removal is selected based on the residual paper position information stored in the nonvolatile memory 207. In the second embodiment, the automatic discharge or manual removal is selected by comparing the time required for automatic discharge of the remaining paper with the time required for manual removal by the operator. In addition, about the matter which is already demonstrated, the same referential mark is attached | subjected and the description is simplified.

  As described above, it is determined that the remaining paper at the position 301 or the position 306 shown in FIG. 3 can be automatically discharged in step S403, and the process proceeds to step S404. In S404 of the second embodiment, the time required to discharge paper from the detected position of the remaining paper to the paper discharge port 45 is compared with the time required for the operator to remove it manually. The paper removal determination unit 206 then determines which is faster between automatic paper discharge and manual removal based on the comparison result. The paper removal determination unit 206 calculates the time (automatic paper discharge time) required to complete the discharge of the residual paper using the transport speed, the distance from the position of the residual paper to the paper discharge port 45, and the size of the residual paper. . The CPU 201 functions as a paper discharge time determining unit that determines an automatic paper discharge time t2 required for automatic paper discharge from the distance from the position of the remaining paper to the paper discharge port of the transport path and the transport speed of the transport unit. The manual removal processing time (manual removal time) estimated in advance for each position of the remaining paper is defined as t3. It is assumed that t3 is previously determined by experiment or simulation at the time of factory shipment. The paper removal determination unit 206 compares the manual removal time t3 with the automatic paper discharge time t2. That is, the paper removal determination unit 206 functions as a comparison unit that compares the manual removal processing time estimated in advance for each remaining paper position with the automatic paper discharge time determined by the paper discharge time determination unit. If the manual removal time t3 is longer than the automatic paper discharge time t2, it is determined that the position of the remaining paper is a position where the automatic paper discharge can shorten the interruption time. On the other hand, if the manual removal time t3 is not longer than the automatic paper discharge time t2, the paper removal determination unit 206 determines that the position of the remaining paper is a position where the interruption time can be shortened by manual removal. Subsequent processing is the same as in the first embodiment.

  Thus, the second embodiment can achieve the same effects as those of the first embodiment. For example, it is assumed that t2 when there is residual paper at the position 301 is 15 seconds, and t2 when there is residual paper at the position 306 is calculated as 20 seconds. Further, t3 is assumed to be, for example, 1 second to 2 seconds. Conventionally, when automatic paper discharge is performed to remove residual paper, it takes 15 seconds when the residual paper is at position 301 and 20 seconds when it is at position 306. On the other hand, according to the present invention, the removal time when there is residual paper at the position 301 or the position 306 can be shortened to 1 second to 2 seconds. As described in the first embodiment, the user-removable mode is provided with a 10-second timeout period. Therefore, after 10 seconds have passed since the transition to the user-removable mode, automatic paper discharge is performed. Executed.

<< Third Embodiment >>
In the third embodiment, a case will be described in which automatic paper discharge needs to be executed even if there is residual paper at any position on the conveyance path where manual removal can be performed. According to FIG. 3B, the remaining paper is present at a position 311 or a position 310 similar to the position 306 or the position 301. Residual paper present at positions 311 and 310 can be removed manually at first glance, but automatic paper discharge is recommended for the following reasons. This is because the leading edge of the paper does not reach the sensor 101 or the sensor 108, and the CPU 201 cannot recognize that the operator has manually removed it. Therefore, when there is residual paper at such a position, the CPU 201 adopts the automatic paper discharge mode instead of the user removable mode.

  In step S <b> 403, the paper removal determination unit 206 determines whether or not automatic paper discharge is possible by determining whether or not the position of the remaining paper is in a predetermined position where automatic paper discharge should be prohibited. For example, the position 310 or the position 311 is stored in advance in the nonvolatile memory 207 as a position where automatic paper discharge should be prohibited. As described above, the non-volatile memory 207 indicates, for each remaining paper position assumed in advance, whether automatic discharge is a position where the interruption time can be shortened or manual removal is a position where the interruption time can be shortened. It functions as a storage means for storing information.

  According to the third embodiment, the automatic paper discharge mode is selected if the position at which manual removal is possible cannot be detected by the sensor even if the position can be manually removed. As a result, it is possible to avoid a situation where manual removal cannot be detected and the image forming operation cannot be restored.

  Note that, even when there is residual paper at the position 310 or the position 311, it may be determined that automatic paper discharge is possible in S 403, and manual removal may be determined earlier than automatic paper discharge in S 404. In this case, after the manual removal time t3 has elapsed, the CPU 201 instructs the driving unit 204 to drive the transport roller for a sufficient time (discharge trial time) until the remaining paper reaches the sensor 101 or the sensor 108. . Further, in step S434, if the sensor 101 or the sensor 108 cannot detect the paper even after the paper discharge trial time has elapsed, the CPU 201 determines that the operator has manually removed the residual paper. In this way, manual removal can also be adopted for residual paper existing at the position 310 and the position 311. Generally, since the paper ejection trial time is several seconds, there will be an advantage that even if the manual removal time t3 is added to this, the time is still shorter than the automatic paper ejection time t2.

<< 4th Embodiment >>
The first to third embodiments are basically examples in which the number of remaining sheets is one. Therefore, in the fourth embodiment, a case where there are a plurality of remaining sheets will be described in detail with reference to FIG. In addition, about the matter which is already demonstrated, the same referential mark is attached | subjected and the description is simplified. If it is determined in S402 that there is residual paper, the process proceeds to S701.

  In step S <b> 701, the paper removal determination unit 206 determines whether all of the plurality of remaining sheets can be automatically discharged. Note that the paper removal determination unit 206 determines whether or not each of the plurality of remaining sheets can be automatically discharged. This determination method is as described in the first embodiment. For example, even if one of a plurality of remaining sheets is present at an automatic paper discharge prohibition position such as position 304 or position 305, automatic paper discharge is impossible. The process proceeds to S410, and the CPU 201 follows the manual removal mode. Execute the process. On the other hand, if it is determined that automatic paper discharge is possible, the process proceeds to S702. In step S <b> 702, the paper removal determination unit 206 determines whether the leading ends of all remaining papers have reached any sensor. As described in the third embodiment, if the position of any remaining paper is the manual removal prohibition position such as the position 310 or the position 311, the completion of the manual removal cannot be detected. Therefore, if the leading ends of all remaining sheets have not reached any sensor, the process proceeds to S430, and the CPU 201 performs processing according to the automatic paper discharge mode.

  On the other hand, if the leading ends of all the remaining sheets are approaching the sensor, the process proceeds to S703. In step S <b> 703, the paper removal determination unit 206 determines whether all the remaining paper positions exist at manual removal recommended positions such as the position 301 and the position 306. If the positions of all the remaining sheets are the position 301 and the position 306, the process proceeds to S420, and the CPU 201 executes processing according to the user removable mode. This is because manual removal is faster than automatic paper discharge if the positions of all the remaining sheets are the positions 301 and 306. On the other hand, if even one sheet remains at a position different from the position 301 or the position 306, the automatic paper discharge is faster than the manual removal, and the process proceeds to S430. As described above, in this embodiment, even when there are a plurality of remaining sheets, it is possible to determine which of the manual removal and the automatic sheet discharge can shorten the interruption time according to the position of the remaining sheets. . Therefore, the interruption time of the image forming process can be shortened compared to the conventional case.

Claims (8)

An image forming apparatus,
Conveying means for conveying the paper in the conveying path;
A jam detecting means for detecting that a paper jam has occurred in the conveyance path;
Position detecting means provided at different positions in the transport path for detecting the position of the paper;
When the removal of the paper detected as jam by the jam detection means is completed, the position detection means detects the position of the paper remaining in the conveyance path, thereby determining the presence of the residual paper and the position of the residual paper. A residual paper discriminating means for discriminating;
If the residual paper determining means determines that residual paper is present in the transport path, the image forming apparatus's image formation interruption time is shortened when the residual paper is automatically discharged by the transport means. Determination means for determining whether it is a position where the interruption time can be shortened by manual removal or
If the determination means determines that manual removal of the position of the remaining paper is a position where the interruption time can be shortened even if automatic paper discharge is possible, a message prompting manual removal is output, and the determination means And a control unit that controls the transport unit to automatically discharge the residual paper when it is determined that the paper is automatically discharged at a position where the interruption time can be shortened rather than manual removal. An image forming apparatus. The determination means includes
When it is determined by the residual paper discrimination means that residual paper is present in the transport path, the position of the residual paper coincides with a position where the residual paper can be automatically discharged when the transport means is operated. Or a first determination unit that determines whether the remaining sheet coincides with a position where the sheet cannot be automatically discharged even when the transport unit is operated;
When the first determination unit determines that the position of the remaining sheet coincides with a position where automatic sheet discharge is possible, the position of the remaining sheet is when the automatic sheet discharge is performed and the image formation time of the image forming apparatus is interrupted. 2nd judging means for judging whether the position corresponding to the position where the interruption time can be shortened or the position where manual removal is the same can be shortened,
The image forming apparatus further includes:
When the first determination means determines that the position of the remaining paper matches the position where automatic paper discharge is impossible, and the second determination means is manually operated even if the position of the residual paper can be automatically discharged. The image forming apparatus according to claim 1, further comprising: a notification unit that outputs a message that prompts the operator to manually remove each time the removal is determined to coincide with a position where the interruption time can be shortened. . The determination means includes
Storage means storing information indicating whether the automatic paper discharge is a position where the interruption time can be shortened or the manual removal is a position where the interruption time can be shortened for each position of the remaining paper assumed in advance. Prepared,
The determination unit compares the position of the residual paper specified by the residual paper determination unit with the information stored in the storage unit, so that the automatic discharge is a position where the interruption time can be shortened. 2. The image forming apparatus according to claim 1, wherein it is determined whether manual removal is a position where the interruption time can be shortened. The determination means includes
A paper discharge time determining means for determining an automatic paper discharge time required for automatic paper discharge from a distance from a position of the residual paper to a paper discharge outlet of the transport path and a transport speed of the transport means;
Comparing means for comparing the manual removal processing time estimated in advance for each position of the residual paper and the automatic paper discharge time determined by the paper discharge time determining means;
If the manual removal processing time is longer than the automatic paper discharge time, the determination unit determines that the position of the remaining paper is a position where the automatic paper discharge can shorten the interruption time. 2. The image forming apparatus according to claim 1, wherein if the time is not longer than the automatic paper discharge time, the position of the remaining paper is determined to be a position where the interruption time can be shortened by manual removal.   If the position of the residual paper is a position where a part of the residual paper is exposed to the outside of the image forming apparatus, the determination unit may manually remove the residual paper rather than executing the automatic paper discharge. 5. The image forming apparatus according to claim 3, wherein it is determined that the interruption time can be shortened. The image forming apparatus includes a manual tray for manually supplying paper,
The image forming apparatus according to claim 5, wherein the residual paper is paper fed from the manual feed tray. The image forming apparatus reverses the sheet on which the image is formed on the first side in order to form an image on the second side of the sheet on which the image is formed on the first side, and sends the image to the image forming unit again. An auxiliary conveyance path,
6. The image forming apparatus according to claim 5, wherein a part of the residual paper is exposed to the outside of the image forming apparatus when the residual paper is fed through an auxiliary conveyance path. It further comprises time measuring means for measuring an elapsed time after outputting the message for prompting manual removal when the determination means determines that the manual removal of the position of the residual paper is a position where the interruption time can be shortened. ,
8. The control unit according to claim 1, wherein the control unit controls the transport unit to automatically discharge the remaining paper when the elapsed time measured by the time measuring unit exceeds a predetermined threshold value. 9. The image forming apparatus according to claim 1.

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