JP2020064230A - Image forming apparatus - Google Patents

Abstract

To improve jam processing performance.SOLUTION: An image forming apparatus comprises: a fixing unit that fixes an image formed on a recording material to the recording material; a detection unit that detects the recording material on a path through which the recording material is conveyed; and a control unit that detects if jam occurs in the conveyance of the recording material based on a signal from the detection unit and controls the operation. When detecting that jam occurs in the conveyance of the recording material, the control unit conveys a subsequent recording material present in the fixing unit to a position at which the subsequent recording material is in contact with or overlaps a preceding recording material preceding immediately before the subsequent recording material in the direction of conveyance of the recording material, and then stops the subsequent recording material.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an image forming apparatus such as a printer or a copying machine that forms an image on a recording material.

  Conventionally, in an image forming apparatus, a fixing unit, which is a fixing unit, is configured to be detachable from a main body of the image forming apparatus, and when a jam of a sheet of recording material occurs and the sheet remains in the fixing unit, the fixing unit It is known to remove the remaining paper by removing the paper. Patent Document 1 discloses a configuration having a door opening / closing detection unit that detects opening / closing of a door and a fixing unit attachment / detachment detection unit that detects attachment / detachment of a fixing unit. When a sheet remains in the fixing unit when a jam occurs, the fixing unit is removed and the remaining sheet is removed. At this time, it is disclosed that if a series of operations of opening the door, removing the fixing unit, mounting the fixing unit, and closing the door are detected in this order, it is determined that the jam has been removed. There is.

  If the fixing unit is driven in a state where a sheet jam occurs and there is a sheet remaining in the fixing unit, the remaining sheet may be wound around a roller in the fixing unit. Once the remaining paper is wrapped around the rollers in the fixing unit, it is very difficult to remove it. Therefore, when the paper jam occurs and the paper remains in the fixing unit as described above, it is necessary to remove the fixing unit and have the user remove the remaining paper.

JP, 2007-333814, A

  To remove the fixing unit from the image forming apparatus, first, the exterior door of the image forming apparatus is opened to expose the fixing unit. After that, the lever that fixes the fixing unit to the image forming apparatus is released. After that, the fixing unit is pulled out from the image forming apparatus, and the sheet sandwiched by the fixing unit is removed. Particularly in an image forming apparatus compatible with printing of A3 size paper, the size of the fixing unit becomes large and the weight becomes heavy. Therefore, the user cannot proceed with the work unless the user holds the fixing unit with both hands. In addition, unfixed toner may remain on the paper sandwiched between the fixing units. Therefore, when removing the paper, the user has to be careful so that the toner does not adhere to the user's hand or the periphery of the image forming apparatus.

  When the paper jam occurs near the fusing unit and the above-mentioned work is required, the paper jam occurs at a position downstream of the fusing unit, and the following paper stops in the fusing unit. However, the same work as the above work may be required.

  The work related to the jam processing imposes a heavy burden on the user, and there is a problem that usability is deteriorated.

  Therefore, an object of the present invention is to provide an image forming apparatus having improved jam handling property and excellent usability.

  To achieve the above object, the present invention provides a fixing unit that fixes an image formed on a recording material onto the recording material, a detection unit that detects the recording material in a path along which the recording material is conveyed, and a detection unit that detects the recording material. And a control unit for controlling the operation by detecting whether a jam has occurred in the conveyance of the recording material based on the signal of, and the control unit has detected that the jam has occurred in the conveyance of the recording material. In some cases, the succeeding recording material existing in the fixing unit is conveyed to a position where it comes in contact with or overlaps with the preceding recording material preceding the succeeding recording material in the recording material conveying direction, and then stopped. And

  According to the present invention, the succeeding recording material existing in the fixing unit is stopped after being conveyed to a position overlapping the preceding recording material that is being conveyed immediately before the succeeding recording material. Can be stopped at a position downstream of the fixing unit. As a result, the user does not need to remove the fixing unit to process the remaining recording material, and the jam handling property is improved.

Cross-sectional view of image forming apparatus Block diagram of image forming device (A) and (b) are sectional views of a main part of the image forming apparatus according to the first embodiment. (A) and (b) are cross-sectional views of a main part of the image forming apparatus according to the second embodiment. Diagram explaining the position of the succeeding paper when a jam occurs in the paper discharge option FIG. 3 is a flowchart showing an operation during jam processing of the image forming apparatus according to the first embodiment. FIG. 3 is a flowchart showing an operation during jam processing of the image forming apparatus according to the first embodiment. FIG. 6 is a flowchart showing an operation during jam processing of the image forming apparatus according to the second embodiment. FIG. 6 is a flowchart showing an operation during jam processing of the image forming apparatus according to the third embodiment.

  Hereinafter, preferred embodiments of the present invention will be illustratively described in detail with reference to the drawings. However, the dimensions, materials, shapes, relative arrangements, and the like of the components described in the following embodiments should be appropriately changed depending on the configuration of the apparatus to which the present invention is applied and various conditions. Therefore, unless otherwise specified, the scope of the present invention is not intended to be limited thereto.

[First Embodiment]
An image forming apparatus according to the first embodiment of the present invention will be described. FIG. 1 is a sectional view of the image forming apparatus. The image forming apparatus shown in FIG. 1 includes an image forming apparatus main body 128, a paper discharge option 180 that is a discharge unit connected to the image forming apparatus main body 128, and an intermediate conveyance unit that connects the image forming apparatus main body 128 and the paper discharge option 180. It consists of 170. The configuration of the image forming apparatus shown in FIG. 1 will be described in detail later.

  FIG. 2 is a block diagram of a control system of the image forming apparatus shown in FIG. The control block of the image forming apparatus will be described with reference to FIG.

  In FIG. 2, the image forming apparatus main body 128 receives print information and image information from the host computer 917 by the video controller 916 in the image forming apparatus main body 128.

  The video controller 916 analyzes print information, and informs the system controller 901 and the discharge option control unit 918, which are control units, under what print conditions image formation is to be performed. Further, the video controller 916 expands the image information into bitmap data and sends it to the system controller 901 as video data.

  The system controller 901, which is a control unit, comprehensively controls the operation of the image forming apparatus based on the data transmitted by the video controller 916. The system controller 901 mainly plays a role of driving each load in the image forming apparatus, collecting and analyzing information of sensors, and exchanging data with the display unit 906, that is, a user interface.

  The internal configuration of the system controller 901 is equipped with the CPU 903 to fulfill the above-mentioned role. The CPU 903 similarly executes various sequences relating to predetermined image formation by using the timer 902 by a program stored in the ROM 904 mounted on the system controller 901. At that time, a RAM 905 is also installed to store data that needs to be temporarily or permanently stored. The RAM 905 stores, for example, a high voltage set value for a high voltage control unit 908 described later, various data described later, image forming command information from the display unit 906 and the video controller 916, and the like.

  The intermediate transfer unit control unit 921 drives the transfer rollers in the intermediate transfer unit by the motor control unit 923 according to an instruction from the system controller 901. Further, the intermediate transfer unit control unit 921 is configured to detect a change in the sensor in the intermediate transfer unit by the sensor input unit 922 and notify the system controller 901.

  The paper discharge option control unit 918 causes the motor control unit 920 to drive the motor in the paper discharge option based on the print conditions transmitted from the video controller 916. Further, the paper discharge option control unit 918 is configured to detect a change in the sensor in the paper discharge option by the sensor input unit 919 and notify the video controller 916. The system controller 901 and the discharge option control unit 918 send and receive information via the video controller 916.

  The system controller 901 obtains information such as printing conditions and density setting values set by the user from the display unit 906 or the video controller 916. On the other hand, the system controller 901 notifies the display unit 906 and the video controller 916 of the state of the image forming apparatus. For example, the number of images to be formed, information as to whether or not an image is being formed, data for indicating the occurrence of a jam and its location to the user, and the like are notified.

  In this image forming apparatus, a plurality of motors, DC loads such as clutches / solenoids, and sensors such as photo interrupters are arranged at various locations inside the apparatus. That is, the recording material is conveyed and each unit is driven by appropriately driving the motor and each DC load, and various sensors monitor the operation.

  Therefore, the system controller 901 detects signals from various sensors by the sensor input unit 911, and the motor control unit 909 controls stop and drive of each motor based on the signals.

  At the same time, the system controller 901 causes the DC load control unit 910 to operate the clutch / solenoid to smoothly advance the image forming operation.

  The system controller 901 also sends various high voltage control signals to the high voltage controller 908. As a result, an appropriate high voltage is applied to the charging rollers 111 to 114, the developing rollers 105 to 108, the primary transfer rollers 119 to 122, the secondary transfer roller 126, etc., which are included in the high voltage unit 914.

  Further, a fixing heater 915 is built in the fixing roller 157 as a heating body of the fixing device 127 shown in FIG. The fixing heater 915 is ON / OFF controlled by an AC driver 912. At this time, the fixing roller is provided with a thermistor 913 as a temperature detector for measuring the temperature of the fixing roller. The A / D converter 907 converts the resistance value change of the thermistor 913 according to the temperature change of the fixing roller into a voltage value, and then inputs the voltage value to the system controller 901 as a digital value. The system controller 901 controls the above-mentioned AC driver 912 based on this temperature data.

  The configuration and operation of the image forming apparatus main body, paper discharge option, and intermediate conveyance unit will be described with reference to FIG. As described above, the image forming apparatus shown in FIG. 1 has an image forming apparatus main body 128, a paper discharge option 180 connected to the image forming apparatus main body 128, and an intermediate connecting the image forming apparatus main body 128 and the paper discharge option 180. The transport unit 170 is included.

  The image forming apparatus main body 128 has a fixing device 127 that is a fixing unit that fixes an image formed on a recording material to the recording material, and forms an image on the recording material that is the recording material. The fixing device 127 will be described later.

  The image forming apparatus main body 128 has four photosensitive drums 101, 102, 103, 104, and obtains a full-color image by forming toner images of four colors using the intermediate transfer belt 123 and superimposing them, so-called in-line system. It is a full-color laser printer.

  Around the photosensitive drums 101 to 104, charging rollers 111 to 114, which are charging devices, and developing rollers 105 to 108, which are developing devices, are arranged, and process cartridges 115 to 118 in which these are unitized are provided from the image forming apparatus main body 128. It has a removable structure.

  Hereinafter, the process cartridge 115 will be described in detail. Since the other three process cartridges 116 to 118 have the same structure, the description thereof will be omitted. The process cartridge 115 is for yellow, the process cartridge 116 is for magenta, the process cartridge 117 is for cyan, and the process cartridge 118 is for black toner.

  The process cartridge 115 includes the photosensitive drum 101 that is rotatably supported. The photosensitive drum 101 is a general organic photosensitive drum having a conductive base such as aluminum and a photoconductive layer formed on the outer periphery thereof as a basic structure. The photosensitive drum 101 is rotationally driven in the direction of the arrow shown by a drum motor, which is a driving unit (not shown).

  A charging roller 111 is arranged above the photosensitive drum 101. The charging roller 111 is in contact with the surface of the photosensitive drum 101 and uniformly charges the surface to a predetermined polarity (negative in this embodiment) and potential. The charging roller 111 is composed of a conductive cored bar arranged in the center and a conductive layer formed on the outer periphery thereof, and is rotatably supported. The charging roller 111 is arranged substantially parallel to the photosensitive drum 101, and is pressed toward the center of the photosensitive drum 101 by pressing means (not shown). The charging roller 111 is driven to rotate as the photosensitive drum 101 rotates in the arrow direction. A bias voltage is applied to the charging roller 111 by a charging high-voltage power source (not shown), so that the surface of the photosensitive drum 101 is uniformly contact-charged.

  The downstream side of the charging roller 111 along the rotation direction of the photosensitive drum 101 is configured to be irradiated with the laser beam L1 from the laser scanner 109. The laser scanner 109 exposes the photosensitive drum 101 by scanning while turning on / off the laser light based on the image information, and the potential of the exposure portion changes, so that the photosensitive drum 101 receives the image information according to the image information. To form an electrostatic latent image.

  The laser scanner 109 is configured to perform exposure for black and magenta, and the laser scanner 110 is configured to perform exposure for cyan and yellow.

  Further, a developing roller 105 is rotatably installed on the downstream side of the irradiation position of the laser beam L1. Toner as a developer is supplied to the developing roller 105 from a developer container (not shown). A developing bias voltage is applied to the developing roller 105 by a developing high-voltage power supply (not shown), so that toner adheres to the exposed portion on the surface of the photosensitive drum, and the electrostatic latent image is developed as a toner image.

  A transfer roller 119 is arranged downstream of the developing roller 105 and below the photosensitive drum 101 with the intermediate transfer belt 123 interposed therebetween. Similarly, a transfer roller 120 is provided below the photosensitive drum 102, a transfer roller 121 is provided below the photosensitive drum 103, and a transfer roller 122 is provided below the photosensitive drum 104.

  The transfer roller 119 is composed of a grounded cored bar and a conductive layer formed in a cylindrical shape on the outer peripheral surface thereof. Further, both ends of the transfer roller 119 in the longitudinal direction are pressed toward the center of the photosensitive drum 101 by pressing members such as springs (not shown). As a result, the conductive layer of the transfer roller 119 is pressed against the surface of the photosensitive drum 101 via the intermediate transfer belt 123 with a predetermined pressing force, and a transfer nip portion is formed between the photosensitive drum 101 and the transfer roller 119. .

  The intermediate transfer belt 123 is sandwiched in the transfer nip portion, and the toner charged by the potential difference between the surface of the photosensitive drum 101 and the transfer roller 119 is transferred from the surface of the photosensitive drum 101 to the surface of the intermediate transfer belt 123. This transfer is called primary transfer.

  After the transfer of the toner image, the photosensitive drum 101 is cleaned of adhering substances such as residual toner by a cleaning unit (not shown).

  The intermediate transfer belt 123 is stretched by three rollers including a counter roller 124 of a secondary transfer roller 126 and a tension roller 125, and is rotationally driven in the arrow direction of the three rollers. The intermediate transfer belt 123 is made of a dielectric resin such as PC, PET, PDVF. The transfer roller 119 is made of conductive urethane sponge.

  The toner images of the respective colors formed on the photosensitive drums 101 to 104 are sequentially transferred onto the intermediate transfer belt 123 as described above. After that, the toner image is conveyed to the secondary transfer portion formed by the secondary transfer roller 126 and the counter roller 124 as the intermediate transfer belt 123 rotates.

  Recording materials are accommodated in the paper feed cassette 140. The image forming apparatus according to the present exemplary embodiment includes a pickup roller 144 as a conveying unit that conveys a recording material to the secondary transfer unit, a conveying roller 148, and a registration roller 160.

  The recording material contained in the paper feed cassette 140 is fed by the pickup roller 144 at the timing when the print instruction command from the video controller 916 is output to the system controller 901. Then, the recording material is conveyed by the conveying roller 148, and further conveyed by the registration roller 160 toward the secondary transfer portion composed of the secondary transfer roller 126 and the counter roller 124.

  When the leading edge of the recording material is detected by the registration sensor 161 which is a detection unit for detecting the presence / absence of the recording material, the transport roller 148 and the registration roller 160 temporarily stop and enter a standby state.

  Then, the system controller 901 outputs a / TOP signal which is an image formation start signal to the video controller 916. The video controller 916 outputs video data in synchronization with the / TOP signal, and exposure is started.

  The system controller 901 restarts the driving of the conveyance roller 148 and the registration roller 160 at a predetermined timing from the / TOP signal. Then, the recording material in the standby state starts to move and is conveyed to the secondary transfer portion.

  Conveying the recording material from the paper feed cassette is called paper feeding, and restarting driving from a paused state is called paper refeeding.

  By feeding and re-feeding paper at a predetermined timing from the start of exposure, the toner image on the intermediate transfer belt overlaps with the recording material at the secondary transfer portion, and the toner image on the recording material The toner image is secondarily transferred without displacement. At this time, a high voltage power source of positive polarity is applied to the secondary transfer roller 126 as a secondary transfer bias from the secondary transfer high voltage power source 132. The recording material on which the toner image is transferred is then further conveyed toward the fixing device 127.

  The untransferred toner that has not been transferred to the recording material and remains on the intermediate transfer belt is scraped off from the intermediate transfer belt by the cleaning blade 131 and collected in a waste toner container (not shown). As a result, the intermediate transfer belt is cleaned and prepared for the next image formation.

  The fixing device 127, which is a fixing unit, includes a fixing roller 157 that is rotatably arranged, and a pressure roller 156 that rotates while being in pressure contact with the fixing roller 157. A fixing heater 915 such as a halogen lamp is provided inside the fixing roller 157, and the temperature of the surface of the fixing roller 157 is adjusted by controlling the electric power supplied to the fixing heater 915.

  When the recording material is conveyed to the fixing device 127, the fixing roller 157 and the pressure roller 156 rotate at a constant speed, and when the recording material passes between the fixing roller 157 and the pressure roller 156, the recording material is almost completely removed from both front and back surfaces. It is pressurized and heated at a constant pressure and temperature. As a result, the unfixed toner image on the surface of the recording material is melted and fixed on the recording material to form a full-color final image.

  The recording material on which the full-color image is fixed passes through the fixing paper discharge sensor 162 and the post-fixing sensor 130 arranged at the exit of the fixing device 127, and is then conveyed to the intermediate conveying unit 170. The fixed paper ejection sensor 162 and the post-fixing sensor 130 are detection units that detect the recording material in the path where the recording material is conveyed in the image forming apparatus main body 128.

  The intermediate conveyance unit 170 connects the image forming apparatus main body 128 and the paper discharge option 180 that is a discharge unit, and conveys the recording material from the image forming apparatus main body 128 to the paper discharge option 180.

  Within the intermediate transport unit, there are three transport rollers, a first intermediate transport roller 172, a second intermediate transport roller 173, and a third intermediate transport roller 174. The first intermediate conveyance roller 172 conveys the recording material discharged from the image forming apparatus main body 128. The second intermediate transport roller 173 is provided on the downstream side of the first intermediate transport roller 172 in the transport direction of the recording material and transports the recording material. The third intermediate transport roller 174 is provided on the downstream side of the second intermediate transport roller 173 in the transport direction of the recording material, and transports the recording material toward the paper discharge option. These three intermediate conveyance rollers are driven by an intermediate conveyance motor (not shown). Inside the intermediate conveyance unit, there is an intermediate conveyance sensor which is a detection unit for detecting the recording material, downstream of each conveyance roller. The first intermediate conveyance sensor 175 is provided downstream of the first intermediate conveyance roller 172 and detects the recording material. The recording medium is provided downstream of the second intermediate conveyance sensor 176 and the second intermediate conveyance roller 173. The third intermediate conveyance sensor 177 is provided downstream of the third intermediate conveyance roller 174 and detects the recording material. The system controller 901, which is a control unit, detects the timing at which the leading edge and the trailing edge of the recording material pass based on the signals from the respective intermediate transport sensors, so that the recording material jams in the intermediate transport unit. The occurrence can be detected.

  An opening / closing door 171 that can be opened and closed is provided above the intermediate conveyance unit 170. By opening the opening / closing door 171, the recording material in the intermediate conveyance unit 170 can be easily removed.

  The recording material conveyed through the intermediate conveying unit 170 is conveyed to the paper discharge option 180.

The discharge option 180, which is a discharge unit, is connected to the image forming apparatus main body 128, and the first discharge bin 185 and the second discharge bin 185 as a stacking unit that stacks the recording material on which the image is fixed by the fixing device 127. It has a bottle 186. The paper discharge option 180 is for sorting and stacking recording materials by the first paper discharge bin 185 and the second paper discharge bin 186.

  The recording material transported from the intermediate transport unit 170 is transported by the first transport roller 181 and the second transport roller 182 in the paper discharge option 180. Then, the recording material is selectively discharged and stacked in the first paper discharge bin 185 or the second paper discharge bin 186 that has been moved up and down by the bin lifting motor 184.

  A discharge option sensor 183, which is a detection unit that detects a recording material, is disposed downstream of the first transport roller 181. The paper discharge option control unit 918 uses the paper discharge option sensor 183 to monitor the timing at which the recording material passes, and is used to detect whether or not a recording paper jam has occurred.

  Although not shown, a processing unit for processing the recording material is provided in the paper discharge option 180, and the recording material is appropriately processed to be processed in the first paper discharge bin 185 or the first paper discharge bin 185. Second, the paper is selectively discharged to the paper discharge bin 186. The processing section includes a stapling section for stapling a bundle of recording materials and a punching section for punching a recording material.

  The above is a schematic description of the image forming apparatus including the image forming apparatus main body 128, the paper discharge option 180, and the intermediate conveying unit 170.

  In such an image forming apparatus, a case where a jam occurs in the paper discharge option 180 during continuous printing will be described.

  FIG. 5 is a diagram showing the conveyance position of the recording material at the moment when the jam occurs in the paper discharge option 180. FIG. 5 is a cross-sectional view of a main part of a sectional view of the image forming apparatus shown in FIG. 1 in which only necessary parts are extracted and shown, and the same parts as those in FIG. 1 are denoted by the same reference numerals.

  In FIG. 5, the paper 200, which is a recording material, is jammed in the paper discharge option 180. The paper discharge option control unit 918 is a jam detecting unit that detects whether a paper jam in the paper discharge option 180 has occurred. The paper discharge option control unit 918 monitors the paper discharge option sensor 183, which is a detection unit for detecting paper, and detects a jam by continuously detecting the presence of paper for a predetermined time or longer. When the paper discharge option control unit 918 detects a jam, it notifies the video controller 916 that a jam has occurred. The video controller 916 notifies the system controller 901 of the image forming apparatus main body 128 that a jam has occurred in the paper discharge option 180.

  At the moment when the system controller 901 receives the jam occurrence notification, as shown in FIG. 5, the three sheets 201, 202, and 203 following the jammed sheet 200 are inside the intermediate conveyance unit 170 and the image forming apparatus main body 128. Is being transported. Here, the sheets 201, 202, and 203 being conveyed in the intermediate conveyance unit 170 and the image forming apparatus main body 128 are recording materials different from the sheet 200 jammed by the sheet discharge option 180.

  In FIG. 5, the sheet 200 is a sheet that is jammed in the sheet discharge option 180. The sheet 201 is a sheet subsequent to the jammed sheet 200 and is being conveyed in the intermediate conveyance unit 170. The sheet 202 is a sheet following the sheet 201 and is being conveyed in the intermediate conveyance unit 170. Further, the sheet 203 is a sheet following the sheet 202, and is being conveyed in the fixing device 127 of the image forming apparatus main body 128.

  The transport position of all the sheets being transported in the image forming apparatus main body 128 is constantly monitored by the system controller 901 which is a control unit. Therefore, at the moment when the paper jam occurs, the paper that is being conveyed on the upstream side of the path through which the recording material is conveyed than the jammed paper will be recorded in the system based on the signal from the sensor that is the detection unit that detects the recording material. The transport position is detected by the controller 901.

  The processing after the system controller 901 receives the notification of the jam occurrence in the paper discharge option 180 from the video controller 916 will be described with reference to FIG. FIG. 6 is a flowchart showing the operation of the image forming apparatus according to the first embodiment at the time of jam processing.

  The system controller 901 constantly monitors whether or not a jam occurrence notification is received in the paper discharge option 180 from the video controller 916 (S101). Here, when the system controller 901 receives the jam occurrence notification, it instructs the intermediate conveyance unit controller 921 to stop the intermediate conveyance motor that drives the intermediate conveyance rollers 172, 173, and 174 (S102). As a result, the sheet 201 and the sheet 202 in the intermediate transport unit 170 are stopped from being transported.

  Next, the system controller 901 determines whether there is a sheet being conveyed in the fixing device 127 (S103). If there is no sheet being conveyed in the fixing device 127, the fixing motor that drives the fixing device 127 is stopped (S105). If there is a sheet being conveyed in the fixing device 127, the driving is continued without stopping the fixing motor. In this embodiment, there is the sheet 203 being conveyed in the fixing device 127, and the sheet 203 continues to be conveyed as it is. Then, the system controller 901 contacts the sheet 203, which is the succeeding recording material existing in the fixing device 127, with the sheet 202, which is the preceding recording material that precedes the preceding sheet 203 by one in the conveying direction of the recording material, or Transport them to the overlapping position. That is, the system controller 901 waits for the leading edge of the sheet 203 to reach the nip of the first intermediate conveyance roller 172 in the intermediate conveyance unit 170 (S104). Then, the system controller 901 stops the fixing motor when the leading edge of the sheet 203 reaches the nip of the first intermediate conveyance roller 172 (S105).

  The position of the sheet at this point is shown in FIG. The sheet 204 shown in FIG. 3A shows a state in which the sheet 203 shown in FIG. 5 has been conveyed and has moved to a position overlapping the preceding sheet 202.

  Since the conveyance of all the sheets is stopped in this state, by opening the opening / closing door 171 of the intermediate conveyance unit 170, the sheets 201 and 202 remaining in the intermediate conveyance unit 170 can be easily removed. Further, the rear end of the paper 204 has also passed through the fixing device 127, and can be pulled out from the door side of the intermediate conveyance unit 170 without removing the fixing device 127 from the image forming apparatus main body 128.

  In the above description, in the case where the length of the sheet being conveyed in the fixing device 127 in the conveying direction is shorter than the conveying distance from the first intermediate conveying roller 172 in the intermediate conveying unit 170 to the fixing device 127. I explained. Therefore, when the sheet being conveyed in the fixing device 127 is conveyed until the leading end reaches the position of the first intermediate conveying roller 172, the trailing end of the sheet comes out of the fixing device 127.

  However, the length of the sheet being conveyed in the fixing device 127 in the conveying direction may be longer than the conveying distance from the first intermediate conveying roller 172 to the fixing device 127. Even in this case, the following may be performed as long as there is a margin for the sheet to form a loop in the transport path before the first intermediate transport roller 172. That is, the sheet is being conveyed in the fixing device 127, the conveyance is continued even after the leading end of the sheet reaches the position of the first intermediate conveying roller 172, and the sheet is continuously conveyed until the trailing end of the sheet leaves the fixing device 127. You may make it stop.

  The processing in this case will be described with reference to the flowchart of FIG. In FIG. 7, the same processes as those in the flowchart of FIG.

  In the flowchart of FIG. 7, the same process is performed until it is determined in S103 whether there is a subsequent sheet being conveyed to the fixing device, and the process after determining that there is a subsequent sheet being conveyed to the fixing device is different.

  In the flowchart of FIG. 7, when it is determined that the fixing device 127 has a succeeding paper sheet being conveyed, the conveyance of the succeeding paper sheet until the trailing edge of the succeeding paper sheet exits the fixing device 127 is monitored (S110).

  This monitoring may be performed by the system controller 901 by calculating the length from the nip of the fixing device 127 to the trailing edge of the succeeding sheet and determining that the sheet has been conveyed by that length. Further, the system controller 901 monitors the fixing paper ejection sensor 162 located downstream of the conveyance path of the fixing device 127 to detect that the trailing edge of the succeeding paper passes the fixing paper ejection sensor 162. May be.

  When the system controller 901 detects that the trailing edge of the succeeding paper has passed through the fixing device 127, the system controller 901 stops the fixing motor that drives the fixing device 127 (S105).

  The position of the sheet at this point is shown in FIG. Since the leading edge of the sheet 204 shown in FIG. 3B reaches the nip position of the first intermediate conveying roller 172 and is continuously conveyed thereafter, a loop is formed at a position before the first intermediate conveying roller 172. It Since the conveyance of all the sheets is stopped in this state, by opening the opening / closing door 171 of the intermediate conveyance unit 170, the sheets 201 and 202 remaining in the intermediate conveyance unit 170 can be easily removed. Further, the rear end of the paper 204 has also passed through the fixing device 127, and can be pulled out from the door side of the intermediate conveyance unit 170 without removing the fixing device 127 from the image forming apparatus main body 128.

  As described above, according to the present exemplary embodiment, when a jam occurs, the succeeding paper is not left in the fixing device, and the remaining paper is conveyed to a position where it is easy to remove the paper. As a result, it is possible to provide an image forming apparatus with improved usability and excellent usability.

[Second Embodiment]
An image forming apparatus according to the second embodiment of the present invention will be described with reference to FIGS. 4 and 8. 4 (a) and 4 (b) are cross-sectional views of essential parts extracted and shown only in the necessary parts of the cross-sectional view of the image forming apparatus shown in FIG. 1. Attached.

  In FIGS. 4A and 4B, the first intermediate conveyance roller 172 is configured to be driven independently of the second intermediate conveyance roller 173 and the third intermediate conveyance roller 174.

  The first intermediate transfer roller 172 is driven by a first intermediate transfer motor (not shown). The second intermediate transfer roller 173 and the third intermediate transfer roller 174 are driven by a second intermediate transfer motor (not shown) that is a motor different from the first intermediate transfer motor.

  Further, in this embodiment, the paper length, which is the length in the paper transport direction, is longer than that in the first embodiment. Specifically, the paper length is longer than the distance from the first intermediate conveyance roller 172 to the fixing device 127. Further, there is not enough margin in the conveyance path so that a sheet can form a loop in front of the first intermediate conveyance roller 172.

  With the above configuration, the processing after the system controller 901 receives the jam occurrence notification in the paper discharge option 180 from the video controller 916 will be described with reference to FIG. FIG. 8 is a flowchart showing the operation of the image forming apparatus according to the second embodiment during the jam processing. In FIG. 8, the same processes as those in the flowchart of FIG. 6 are given the same numbers.

  The system controller 901 constantly monitors whether or not a jam occurrence notification is received in the paper discharge option 180 from the video controller 916 (S101). Here, when the system controller 901 receives the jam occurrence notification, the system controller 901 instructs the intermediate conveyance unit controller 921 to stop the second intermediate conveyance motor that drives the intermediate conveyance rollers 173 and 174. As a result, the second intermediate conveyance roller 173 and the third intermediate conveyance roller 174 are stopped (S111), and the sheet 205 in the intermediate conveyance unit 170 is stopped.

  Next, the system controller 901 determines whether there is a sheet being conveyed in the fixing device 127 (S103). If there is no sheet being conveyed in the fixing device 127, the intermediate conveyance unit controller 921 is instructed to stop the first intermediate conveyance motor that drives the first intermediate conveyance roller 172. As a result, the first intermediate conveyance roller 172 is stopped (S113). Then, the fixing motor that drives the fixing device 127 is stopped (S105).

  If there is a sheet being conveyed in the fixing device 127, the driving is continued without stopping the first intermediate conveying motor and the fixing motor. In this embodiment, since there is the sheet 206 being conveyed in the fixing device 127, the sheet 206 is continuously conveyed as it is.

  Then, the system controller 901 contacts the sheet 206, which is the succeeding recording material existing in the fixing device 127, with the sheet 205, which is the preceding recording material that precedes the preceding sheet 206 by one in the recording material conveyance direction, or Transport them to the overlapping position. That is, the system controller 901 waits for the leading edge of the sheet 206 to reach the nip of the second intermediate conveyance roller 173 in the intermediate conveyance unit 170 (S112).

  Then, when the leading edge of the sheet 206 reaches the nip of the second intermediate conveyance roller 173, the system controller 901 instructs the stop of the first intermediate conveyance roller (S113) and the stop of the fixing motor (S105). .

  The position of the sheet at this point is shown in FIG. The sheet 207 shown in FIG. 4B shows a state in which the sheet 206 shown in FIG. 4A has been conveyed and moved to a position where it overlaps the preceding sheet 205.

  Since the conveyance of all sheets is stopped in this state, by opening the opening / closing door 171 of the intermediate conveyance unit 170, the sheet 205 remaining in the intermediate conveyance unit 170 can be easily removed. Further, the sheet 207 has also passed through the fixing device 127 at the rear end, and can be pulled out from the door side of the intermediate conveyance unit 170 without removing the fixing device 127 from the image forming apparatus main body 128.

  As described above, in this embodiment, the first intermediate transport roller and the second and third intermediate transport rollers in the intermediate transport unit 170 can be independently driven. With this configuration, even when the paper length of the succeeding paper is longer than the distance from the first intermediate transfer roller 172 to the fixing device 127, the second intermediate transfer roller downstream of the first intermediate transfer roller is in front of the second intermediate transfer roller. At the position of, it can be overlaid on the preceding paper.

  In this embodiment, the succeeding paper is superposed on the preceding paper at a position before the second intermediate conveying roller, but the present invention is not limited to this. Similar to the first embodiment described above, it is possible to stack the succeeding paper on the preceding paper before the first intermediate conveying roller. That is, in the present embodiment, the succeeding paper can be superposed on the preceding paper at two positions before the first intermediate conveying roller or before the second intermediate conveying roller.

  Furthermore, it goes without saying that if the first, second, and third intermediate conveying rollers can be independently driven, it is possible to superimpose the succeeding sheet on the preceding sheet before the respective intermediate conveying rollers.

[Example 3]
An image forming apparatus according to the third embodiment of the present invention will be described with reference to FIG. FIG. 9 is a flowchart showing the operation of the image forming apparatus according to the third embodiment during the jam processing.

  In the first and second embodiments, the opening / closing door of the intermediate conveyance unit is opened to allow the user to remove the succeeding sheet that has been conveyed to the position where it overlaps the preceding sheet.

  On the other hand, in the present embodiment, not the removal processing by the user, but the automatic discharge processing for automatically discharging the remaining preceding paper and the succeeding paper overlapping the preceding paper is performed. However, it is necessary to detect a jam during the automatic discharge process because a jam may occur during the conveyance of the recording material even during the automatic discharge process.

  In the jam detection of this embodiment, when the remaining preceding paper and the succeeding paper that overlaps with this are automatically discharged, the remaining paper remains in the path for conveying the recording material. That is, so-called stay jam detection is performed. In the jammed jam detection, the system controller 901 detects the leading edge of the residual paper to be ejected based on a signal from a sensor that is a detection unit that detects a recording material in the conveyance path, and then detects the length of the residual paper in the conveyance direction. This is because the trailing edge of the remaining sheet cannot be detected even if the sheet is conveyed.

  In the present embodiment, the remaining sheet to be discharged is stopped in a state where the preceding sheet and the succeeding sheet are overlapped, so that the sensor cannot detect the trailing edge of the preceding sheet and the leading edge of the succeeding sheet. Therefore, in the present embodiment, the length in the transport direction from the leading edge of the preceding sheet to the trailing edge of the succeeding sheet is detected, and this length is set as the detection condition for the accumulated jam. That is, in the present embodiment, during the execution of the automatic discharge process, the condition of the jam jam detection based on the signal from the sensor according to the length from the leading edge of the preceding sheet to the trailing edge of the succeeding sheet stacked on the preceding sheet. Is changing.

  As shown in FIG. 9, in the present embodiment, the system controller 901 first waits for the completion of jam processing for removing the jammed paper in the paper discharge option 180 (S201). This is because the paper discharge option control unit 918 monitors the paper discharge option sensor 183, detects that the jammed paper in the paper discharge option 180 has been removed, and notifies the system controller 901 via the video controller 916. Done in. Then, it is determined whether there is a residual sheet to be automatically ejected (S202). This is performed by the system controller 901 by monitoring each sensor that detects a sheet in the transport path. If there is no remaining sheet to be automatically ejected, such as when the user has already removed the remaining sheet, the automatic ejection does not need to be performed, so the automatic ejection process is not started.

  On the other hand, when there is a residual sheet to be automatically discharged, the length 187 (see FIG. 3A) in the transport direction from the leading edge of the remaining preceding sheet to the trailing edge of the following sheet is detected (S203). This is performed by the system controller 901 by calculating from the leading edge position and the sheet length of each residual sheet. Then, the automatic discharging process is started (S204). In this embodiment, specifically, the system controller 901 gives a drive instruction for a paper discharge option, a drive instruction for an intermediate conveyance roller, and a drive instruction for a fixing motor. Then, the process waits until the second intermediate conveyance sensor 176 shown in FIG. 3A detects the presence of paper (S205).

  In the present embodiment, the waiting is continued until the presence of paper can be detected. However, if the presence of paper cannot be detected even after the lapse of a predetermined time, a delay jam may be set to interrupt the automatic discharge process. .

  When detecting the presence of paper, the system controller 901 uses the timing as a starting point, and adds the length of the jam margin of 100 mm to the length from the leading edge of the preceding sheet to the trailing edge of the succeeding sheet calculated in S203. Is monitored (S206). If the second intermediate conveyance sensor 176 detects that there is no paper during the monitoring of S206, it is determined that the remaining paper has been conveyed without a conveyance failure, and the automatic discharge process ends (S209).

  On the other hand, during the monitoring of S206, even if the sheet is conveyed by the distance from the leading edge of the preceding sheet to the trailing edge of the succeeding sheet plus the length of the jam margin of 100 mm, the second intermediate conveyance sensor 176 detects that there is no sheet. If it cannot be detected, the jammed jam is detected (S208).

  In addition, in this embodiment, the configuration of the stay jam detection using the second intermediate conveyance sensor 176 is illustrated, but the present invention is not limited to this. For example, the stay jam detection using the third intermediate conveyance sensor 177 may be similarly performed. Further, in the present embodiment, the jam margin added to the length from the leading edge of the preceding sheet to the trailing edge of the succeeding sheet is set to 100 mm, but the invention is not limited to this value, and an appropriate value may be appropriately set according to the device configuration. Just decide.

  As described above, according to the present embodiment, it is not necessary for the user to open the opening / closing door of the intermediate conveyance unit and perform the removal processing of the remaining paper, so that the jam processing property is further improved and the usability is excellent. An image forming apparatus can be provided.

[Other Examples]
In the above-described embodiment, four process cartridges that can be attached to and detached from the main body of the image forming apparatus are used, but the number of these process cartridges is not limited and may be set appropriately as needed.

  Further, in the above-mentioned embodiment, the laser scanner is used as the exposing means, but the exposing means is not limited to this, and an LED array or the like may be used.

  Further, in the above-described embodiment, as the process cartridge detachable from the main body of the image forming apparatus, the process cartridge integrally including the photosensitive drum and the charging unit, the developing unit and the cleaning unit as the process unit acting on the photosensitive drum is provided. Illustrated. However, it is not limited to this. In addition to the photosensitive drum, a process cartridge that integrally includes any one of a charging unit, a developing unit, and a cleaning unit may be used.

  Further, in the above-described embodiment, the structure in which the process cartridge including the photosensitive drum is attachable to and detachable from the main body of the image forming apparatus is illustrated, but the invention is not limited to this. For example, an image forming apparatus in which each constituent member is incorporated, or an image forming apparatus in which each constituent member is detachable may be used.

  Further, in the above-described embodiment, the printer is exemplified as the image forming apparatus, but the present invention is not limited to this. For example, the image forming apparatus may be another image forming apparatus such as a copying machine or a facsimile machine, or another image forming apparatus such as a multi-function machine that combines these functions. Further, an example of an image forming apparatus which uses an intermediate transfer member, sequentially transfers the toner images of the respective colors to the intermediate transfer member, and transfers the toner images carried on the intermediate transfer member to a recording material at once is illustrated. However, it is not limited to this. An image forming apparatus may be used which uses a recording material carrier and sequentially transfers the toner images of the respective colors onto the recording material carried by the recording material carrier. Similar effects can be obtained by applying the present invention to these image forming apparatuses.

127 Fixing device 128 Image forming apparatus main body 130 Post-fixing sensor 162 Fixing ejection sensor 170 Intermediate transport unit 172 First intermediate transport roller 173 Second intermediate transport roller 174 Third intermediate transport roller 175 First intermediate conveyance sensor 176 ... Second intermediate conveyance sensor 177 ... Third intermediate conveyance sensor 180 ... Paper ejection option 181 ... First conveyance roller 182 ... Second conveyance roller 183 ... Paper ejection option sensor 184 ... Bin lifting motor 185 ... First Paper ejection bin 186 ... Second paper ejection bin 901 ... System controller 916 ... Video controller 918 ... Paper ejection option control unit 921 ... Intermediate conveyance unit control unit

Claims (12)

A fixing unit for fixing the image formed on the recording material to the recording material;
A detection unit that detects the recording material in the path where the recording material is conveyed,
A control unit that detects whether a jam occurs in the conveyance of the recording material based on a signal from the detection unit and controls the operation,
Have
When the control unit detects that a jam has occurred in the conveyance of the recording material, the control unit causes the succeeding recording material existing in the fixing unit to precede the succeeding recording material in the conveying direction of the recording material. An image forming apparatus characterized in that after being conveyed to a position where it comes into contact with or overlaps with a preceding recording material, it is stopped.   When the control unit detects that a jam has occurred in the conveyance of the recording material, it stops the conveyance of the preceding recording material, and then conveys the succeeding recording material to a position where the succeeding recording material contacts or overlaps with the preceding recording material. The image forming apparatus according to claim 1, wherein the image forming apparatus is stopped.   Based on a signal from the detection unit, the control unit determines that the length of the succeeding recording material in the conveyance direction is such that the trailing edge of the succeeding recording material is fixed when the succeeding recording material is superposed on the preceding recording material. 3. When the length is detected to be a position downstream of the set in the transport direction, the subsequent recording material is transported to a position overlapping the preceding recording material and then stopped. The image forming apparatus according to item 1.   Based on a signal from the detection unit, the control unit determines that the length of the succeeding recording material in the conveyance direction is such that the trailing edge of the succeeding recording material is fixed when the succeeding recording material is superposed on the preceding recording material. When it is detected that the length of the subsequent recording material is present, the subsequent recording material is conveyed to a position where it overlaps with the preceding recording material, and the subsequent recording material is moved until the trailing edge of the subsequent recording material passes through the fixing section. The image forming apparatus according to claim 1, wherein the image forming apparatus is stopped after being conveyed. An image forming apparatus main body having the fixing unit and forming an image on a recording material;
A discharge unit connected to the main body of the image forming apparatus, having a stacking unit for stacking the recording material on which the image is fixed by the fixing unit;
An intermediate conveyance unit that connects the image forming apparatus main body and the discharge unit and conveys a recording material from the image forming apparatus main body to the discharge unit;
Have
When the controller detects that a jam has occurred in the conveyance of the recording material, the position of the jammed recording material and the preceding recording material preceding the succeeding recording material existing in the fixing unit Position, the position of the succeeding recording material existing in the fixing section, and the information on the length of the succeeding recording material in the conveying direction are detected based on the signal from the detection section, and these information meet specific conditions. 3. The image forming apparatus according to claim 1, wherein, when the recording medium is filled, the succeeding recording material is conveyed to a position where it comes into contact with or overlaps with the preceding recording material and then stopped. The control unit, based on the signal from the detection unit,
The position of the preceding recording material is in the intermediate transport unit,
The position of the succeeding recording material is upstream of the preceding recording material in the conveying direction of the recording material, and is in the fixing section,
The length of the succeeding recording material in the transport direction is a length such that when the succeeding recording material is superposed on the preceding recording material, the trailing edge of the succeeding recording material is at a position downstream of the fixing unit in the transport direction. Is detected,
The image forming apparatus according to claim 5, wherein the subsequent recording material is conveyed to a position overlapping the preceding recording material and then stopped. The control unit, based on the signal from the detection unit,
When it is detected that the length of the subsequent recording material in the transport direction is the length that the trailing edge of the subsequent recording material exists in the fixing unit when the subsequent recording material is superposed on the preceding recording material,
7. The method for transporting the subsequent recording material to a position overlapping the preceding recording material, further transporting the subsequent recording material until the trailing edge of the subsequent recording material passes through the fixing section, and then stopping the subsequent recording material. The image forming apparatus according to item 1. The intermediate transport unit is provided on the first intermediate transport roller that transports the recording material discharged from the image forming apparatus main body, and downstream of the first intermediate transport roller in the transport direction, and transports the recording material. A second intermediate conveying roller, and a configuration in which the first intermediate conveying roller and the second intermediate conveying roller are independently driven,
The control unit, based on the signal from the detection unit,
When it is detected that the length of the subsequent recording material in the transport direction is longer than the distance from the first intermediate transport roller to the fixing unit,
7. The image forming apparatus according to claim 6, wherein the first intermediate conveyance roller and the fixing unit are stopped after the succeeding recording material is conveyed to a position where the succeeding recording material overlaps with the preceding recording material.   9. The intermediate conveyance unit has a door that can be opened and closed, and is configured such that the recording material in the intermediate conveyance unit can be taken out when the door is opened. The image forming apparatus according to any one of items.   10. The automatic discharge process of automatically discharging the remaining recording material without the user's removal processing after the processing of removing the jammed recording material is completed, the control unit performing the automatic discharge processing. The image forming apparatus according to any one of items.   During execution of the automatic ejection process, the control unit outputs a signal from the detection unit according to the length from the leading end of the preceding recording material to the trailing end of the succeeding recording material that is superposed on the preceding recording material. 11. The image forming apparatus according to claim 10, wherein the condition for detecting whether a jam has occurred in the conveyance of the recording material based on the condition is changed.   The image forming apparatus according to claim 1, wherein the subsequent recording material and the preceding recording material are recording materials different from a jammed recording material.

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