JP2017026836A - Image formation device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image formation device using roll sheets, capable of reducing generation of wastepaper even when a failure which affects to fixation occurs.SOLUTION: A control part acquires a job containing coverage information of an image to be printed on a roll sheet (S100), and starts printing (S110). Then, the control part determines whether or not jam occurs during job execution (S120). When it is determined that jam occurs, jam processing is executed (S130). When the jam is solved (S140), the control part determines whether or not, a blank sheet transport distance of the roll sheet required for cleaning a toner which adheres to a fixation part exceeds a blank sheet transport distance of a default roll sheet (S150). When it is determined that the distance exceeds the blank sheet transport distance of the default roll sheet, the distance is changed to a blank sheet transport distance in which a length for shortage for fixation cleaning is considered (S160). Then printing is restarted, and the blank sheet transport control is executed based on the changed blank sheet transport distance, for performing cleaning of the fixation part (S170).SELECTED DRAWING: Figure 5

Description

  The present invention relates to an image forming apparatus.

  2. Description of the Related Art Conventionally, image forming apparatuses having a plurality of functions that employ an electrophotographic method have been widely used. In a general image forming apparatus, a latent image carried on a photosensitive member is developed into a toner image by a developing unit, and then the developed toner image is transferred to a sheet via an intermediate transfer belt, and then transferred. Image forming processing is performed through a series of processes in which a toner image is fixed on a sheet by a fixing unit.

  Here, in the fixing unit, a fixing member such as a fixing roller or a fixing belt may be stained with toner over time, or the toner may adhere to the fixing member due to a paper jam. In such a case, when a new sheet is passed through the fixing unit, the toner remaining on the fixing member adheres to the sheet and becomes dirty, resulting in a problem that the quality of the product is impaired. For this reason, conventionally, a process of cleaning the toner adhering to the fixing member by transporting a blank sheet on which toner is not transferred to the fixing unit has been performed.

  For example, Patent Document 1 discloses an image forming apparatus that, when it is determined that a jam has occurred in a fixing unit, varies the number of blank sheets to be passed for cleaning according to the printing rate (coverage) of the entire page. ing. Patent Document 2 discloses an image forming apparatus that cleans a fixing unit by conveying a blank sheet by instructing the number of print output sheets for cleaning by an operator's operation. Patent Document 3 discloses an image forming apparatus that conveys a blank sheet when it is determined that the fixing unit needs to be cleaned according to the contamination state of the fixing unit based on the detection result of the detection unit.

JP 2007-65328 A Japanese Patent Laid-Open No. 2003-149979 JP 2014-095836 A

  Incidentally, in recent years, an image forming apparatus using a long recording medium such as roll paper has been used. In an image forming apparatus using roll paper, in order to avoid thermal damage to the roll paper when the temperature of the fixing unit rises (warm-up), the white paper roll paper on which the toner image is not transferred is conveyed. For this reason, when a jam occurs in which unfixed toner remains in the fixing unit, when the fixing unit is cleaned in the same manner as the image forming apparatuses disclosed in Patent Documents 1 to 3, blank paper is again used only for cleaning purposes. Therefore, there is a problem that the amount of waste paper for the conveyance of the white paper increases when the temperature of the fixing unit increases.

  Therefore, the present invention has been made in view of the above problems, and an object of the present invention is to reduce the occurrence of scraping paper even in the case where a defect that affects fixing occurs in an image forming apparatus using roll paper. An object of the present invention is to provide an image forming apparatus that can perform the above-described process.

  In order to solve the above problems, the present invention provides an image forming unit that transfers a toner image formed on an image carrier to roll paper, and the toner image transferred to the roll paper by the image forming unit A fixing unit that fixes the toner image on the paper, and a white paper conveyance that conveys the roll paper on which the toner image is not transferred in a state where the fixing unit is pressure-bonded before the image formation of the toner image on the image carrier is started. A control unit that performs control, and when the trouble that unfixed toner remains in the fixing unit occurs, the control unit performs the blank sheet conveyance control after the trouble is recovered, thereby controlling the fixing unit. In addition to performing cleaning, the image forming start timing of the toner image on the image carrier is changed.

  In the present invention, the problem that unfixed toner remains in the fixing unit is that a fixing member such as a fixing roller or a fixing belt is contaminated with toner due to the transport of roll paper over time, or the fixing member is jammed by roll paper. In some cases, toner adheres to the toner.

  According to the present invention, since the blank paper conveyance after recovery from the problem affecting the fixing is used for cleaning the fixing unit, it is possible to reduce the waste paper. In addition, since the image formation start timing is changed, it is possible to reliably prevent image smearing during fixing.

1 is a diagram illustrating a configuration example of an image forming system according to an embodiment of the present invention. 1 is a block diagram illustrating a functional configuration example of an image forming system. FIG. 6 is a diagram for explaining a relationship between image coverage, a conveyance distance of a white paper roll for fixing cleaning, and whether or not image formation timing is changed. FIG. 6 is a diagram for explaining a default blank paper conveyance distance in a color mode and a monochrome mode. 10 is a flowchart illustrating an operation example of the image forming system when a jam that affects fixing occurs.

  Hereinafter, preferred embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. In addition, the dimension ratio of drawing is expanded on account of description and may differ from an actual ratio.

<First Embodiment>
[Configuration Example of Image Forming System 100]
FIG. 1 shows an example of a schematic configuration of an image forming system 100 according to an embodiment of the present invention. As shown in FIG. 1, the image forming system 100 forms a predetermined image on a roll paper P as continuous paper. The image forming system 100 includes a paper feeding device 200, an image forming device 300, and a winding device 400.

  The sheet feeding device 200 is disposed upstream of the image forming apparatus 300 in the sheet conveyance direction W1 and includes a mounting unit 210. The mounting unit 210 includes a shaft, a drive motor, and the like, and is configured to be able to mount the rolled roll paper P. Based on a job start instruction, the paper feeding device 200 feeds the roll paper P from the mounting unit 210 and feeds the roll paper P to the image forming apparatus 300 through a plurality of transport rollers 212 and 214.

  The image forming apparatus 300 is called a tandem type image forming apparatus, and includes an automatic document feeder 312 and an apparatus main body 312. The automatic document conveyance unit 312 is attached to the upper part of the apparatus main body 312 and sends out the paper set on the conveyance table to the image reading unit 309 of the apparatus main body 312 by a conveyance roller or the like.

  The apparatus main body 312 includes an operation display unit 360, an image reading unit 309, an image forming unit 310, an intermediate transfer belt (image carrier) 308, and a fixing unit 340.

  The operation display unit 360 includes a touch panel in which a display unit and an input unit are combined, and a plurality of operation keys including a start key and a determination key provided in a peripheral part of the touch panel. The operation display unit 360 displays an operation screen or the like on the screen, or receives information such as an image forming condition input by a touch operation on the operation screen or an operation key operation.

  The image reading unit 309 scans and exposes the document placed on the document table or the document transported by the automatic document transport unit 312 by the optical system of the scanning exposure device, and the scanned image of the document is CCD (Charge Coupled Device). ) Photoelectric conversion is performed by an image sensor to generate an image information signal. The image information signal is output to the image forming unit 310 after being subjected to analog processing, analog / digital (hereinafter referred to as A / D) conversion processing, pseudo correction, image compression processing, and the like by an image processing unit (not shown).

  The image forming unit 310 forms an image by an electrophotographic method, and includes an image forming unit 310Y that forms a yellow (Y) image, an image forming unit 310M that forms a magenta (M) image, It has an image forming unit 310C that forms a cyan (C) color image and an image forming unit 310K that forms a black (K) color image. In this example, common function names, for example, Y, M, C, and K indicating colors to be formed are added to the back of the reference numeral 10.

  The image forming unit 310Y includes a photosensitive drum 301Y, a charging unit 302Y, an exposure unit (optical writing unit) 303Y, a developing unit 304Y, and a cleaning unit 306Y disposed around the photosensitive drum 301Y. The image forming unit 310M includes a photosensitive drum 301M, and a charging unit 302M, an exposure unit 303M, a developing unit 304M, and a cleaning unit 306M disposed around the photosensitive drum 301M. The image forming unit 310C includes a photosensitive drum 301C, and a charging unit 302C, an exposure unit 303C, a developing unit 304C, and a cleaning unit 306C disposed around the photosensitive drum 301C. The image forming unit 310K includes a photosensitive drum 301K, and a charging unit 302K, an exposure unit 303K, a developing unit 304K, and a cleaning unit 306K disposed around the photosensitive drum 301K.

  Respective photosensitive drums (image carriers) 301Y, 301M, 301C, 301K, charging units 302Y, 302M, 302C, 302K, exposure units 303Y, 303M, 303C, 303K, development in the image forming units 310Y, 310M, 310C, 310K The units 304Y, 304M, 304C, and 304K, the cleaning units 306Y, 306M, 306C, and 306K have a common configuration. In the following description, Y, M, C, and K are not used unless particularly distinguished.

  The charging unit 302 charges the surface of the photosensitive drum 301 almost uniformly. The exposure unit 303 is configured by, for example, an LPH (LED Print Head) having an LED array and an imaging lens, or a polygon mirror type laser exposure scanning device, and the photosensitive drum 301 is irradiated with laser light based on an image information signal. Scan to form an electrostatic latent image. The developing unit 304 develops the electrostatic latent image formed on the photosensitive drum 301 with toner. As a result, a toner image (image) that is a visible image is formed on the photosensitive drum 301.

  The intermediate transfer belt 308 is stretched by a plurality of rollers and is rotatably supported. Along with the rotation of the intermediate transfer belt 308, the primary transfer roller 307 and the photosensitive drum 301 rotate, and a predetermined voltage is applied between the primary transfer roller 307 and the photosensitive drum 301, whereby the photosensitive member. The toner image formed on the drum 301 is transferred onto the intermediate transfer belt 308 (primary transfer).

  The sheet feeding / conveying unit 320 includes, for example, a plurality of conveying rollers and a driving motor that rotationally drives these rollers. The paper feeding / conveying unit 320 feeds the roll paper P conveyed from the paper feeding device 200 to the secondary transfer unit 330 by rotating a plurality of conveying rollers by driving a drive motor. A tension adjusting unit 324 for applying a predetermined tension to the conveyed roll paper P is provided on the upstream side of the paper transport direction W1 of the paper feed transport unit 320.

  The secondary transfer unit 330 includes a pair of transfer rollers, and roll paper on which the Y, M, C, and K color toner images transferred onto the intermediate transfer belt 308 are conveyed by the sheet feeding and conveying unit 320. Batch transfer to the surface of P (secondary transfer).

  The fixing unit 340 includes a fixing roller, a pressure roller, a heating roller, and a fixing belt. The fixing unit 340 fixes the toner image on the surface of the roll paper P to the roll paper P by applying pressure and heat treatment to the roll paper P to which the toner image has been transferred in the secondary transfer unit 330. The roll paper P that has been subjected to the fixing process is conveyed to the paper discharge conveyance unit 350.

  The paper discharge conveyance unit 350 includes, for example, a plurality of conveyance rollers and a drive motor that rotationally drives them. The paper discharge conveyance unit 350 conveys the roll paper P fixed by the fixing unit 340 to the subsequent winding device 400 by rotating a plurality of conveyance rollers by driving the drive motor.

  The paper detection unit 370 is provided downstream of the fixing unit 340 in the paper transport direction W1 and outside the paper discharge port 352 (side surface part of the apparatus main body 312). The paper detection unit 370 is composed of, for example, an encoder, and detects whether or not a jam affecting the fixing unit 340 has occurred by detecting the presence or absence of rotation of the conveyance roller 372 (conveyance state of the roll paper P). .

  In this example, it is assumed that when the paper detection unit 370 determines that the conveyance of the roll paper P is stopped, a jam occurs in which toner remains on a fixing member such as a fixing belt of the fixing unit 340. Of course, based on the detection result of the sensor installed in the other conveyance path of the image forming apparatus 300 or the sensor installed in the paper feeding apparatus 200, it is determined whether or not a jam in which toner remains on the fixing member has occurred. May be. Further, a detection unit that detects toner attached to the fixing unit 340 may be provided, and it may be determined whether or not a problem that the toner remains in the fixing unit 340 has occurred based on a detection result of the detection unit.

  The winding device 400 is disposed on the downstream side of the image forming apparatus 300 in the paper transport direction W1 and includes a winding unit 410. The winding unit 410 includes, for example, a shaft, a drive motor, and the like, and winds the roll paper P that is discharged from the image forming apparatus 300 and conveyed via the conveyance rollers 412 and 414.

[Block Configuration Example of Image Forming System 100]
FIG. 2 is a block diagram illustrating an example of a functional configuration of the image forming system 100 according to the second embodiment. As shown in FIG. 2, the image forming system 100 includes a control unit 50 for controlling the operation of the entire system. The control unit 50 includes a CPU (Central Processing Unit) 52, a ROM (Read Only Memory) 54, and a RAM (Random Access Memory) 56. The CPU 52 controls each part of the image forming system 100 by executing the software (program) read from the ROM 54, and when a jam that affects fixing occurs, a blank sheet corresponding to the image coverage (image forming conditions) Carry out transport control and so on.

  The control unit 50 includes an operation display unit 360, a paper feed conveyance unit 320, a paper discharge conveyance unit 350, an image forming unit 310, a storage unit 380, a paper detection unit 370, a fixing unit 340, and a pressure separation. The mechanism 342 and the communication unit 390 are connected to each other.

  The storage unit 380 is configured by, for example, a nonvolatile semiconductor memory (so-called flash memory) or an HDD (Hard Disk Drive). The storage unit 380 stores job information including image coverage and the like transmitted from the computer 500, which will be described later, and a table TB used when acquiring a blank paper conveyance distance after the occurrence of a jam.

  The paper detection unit 370 detects the presence or absence of rotation of the transport roller 372 and supplies a signal based on the detection result to the control unit 50.

  The fixing unit 340 controls on / off of the heater based on an instruction from the control unit 50 to heat the fixing belt or the like to a predetermined temperature. The press-separation / separation mechanism 342 presses the pressure roller and the fixing roller based on the control of the control unit 50 or separates (releases the press-fit). In addition, about the crimping | separation separation mechanism 342, since a well-known technique is employable, detailed description is abbreviate | omitted.

  The communication unit 390 includes a communication interface and is connected to a personal computer (hereinafter referred to as a computer) 500 via a network such as a LAN. The computer 500 includes an operation unit, a display unit, a calculation unit, and the like, and transmits information on a job input by the user to the communication unit 390 of the image forming system 100.

  Operations of the other operation display unit 360, the paper feed conveyance unit 320, the paper discharge conveyance unit 350, and the image forming unit 310 are also controlled by the control unit 50.

[Configuration example of table TB]
FIG. 3 shows an example of the configuration of the table TB used when changing the blank transport distance for fixing cleaning in accordance with the image coverage. As shown in FIG. 3, the table TB includes the coverage of the image to be printed on the roll paper P, the blank paper transport distance D1 of the roll paper P for fixing cleaning, and the blank paper transport distance D2 of the default roll paper P (color mode). In this case, it is referred to as a blank paper transport distance D2c, and in the monochrome mode, it is referred to as a blank paper transport distance D2m) and whether or not the image forming timing has been changed. The blank paper transport distance D1 can be obtained by an experiment based on image coverage in advance.

  FIG. 4 is a diagram for explaining the blank paper transport distances D2c and D2m of the default roll paper P. The blank paper transport distance D2c (thick line) of the default roll paper P in the color mode is equal to the distance from the image forming start position P1 of the exposure unit 303Y of the photosensitive drum 301Y to the nip part P2 of the fixing unit 340. This is the minimum distance at which the blank roll paper P must be conveyed after the jam recovery and before the start of printing. In this example, at the blank paper transport distance D2c of the default roll paper P, the meandering of the roll paper P that occurs when the fixing unit 340 is crimped after the jam return is prevented, or the toner that adheres to the fixing unit 340 due to the occurrence of a jam. The white paper transport control for executing the cleaning is performed. The default blank paper conveyance distance D2c is determined by the design dimensions of the apparatus, and is “2 m”, for example.

  The default blank paper transport distance D2m in the monochrome mode is equal to the distance from the image forming start position P3 of the exposure unit 303K of the photosensitive drum 301K to the nip part P2 of the fixing unit 340, and is printed after the jam recovery. This is the minimum distance at which the blank roll paper P must be conveyed by the start. In this example, at the blank paper conveyance distance D2m of the default roll paper P, the meandering of the roll paper P that occurs when the fixing unit 340 is pressure-bonded after the jam recovery is prevented, or the toner attached to the fixing unit 340 due to the occurrence of the jam. The white paper transport control for executing the cleaning is performed. The default blank paper conveyance distance D2m is determined by the design dimensions of the apparatus and is, for example, “0.7 m”.

  Returning to FIG. 3, for example, when the image coverage is “80% or less” and the print mode is “color mode”, the blank transport distance D1 of the roll paper P for fixing cleaning is “1 m”, which is the default blank paper. The transport distance D2c is “2 m”. For this reason, the blank paper transport distance D1 of the roll paper P for fixing cleaning is shorter than the default blank paper transport distance D2c. In this case, the control unit 50 executes the image forming operation using a preset default image forming start timing (time). The default image formation start timing may be stored in the table TB in association with image coverage or the like.

  When the image coverage is “120% to 240%” and the print mode is “color mode”, the blank paper transport distance D1 of the roll paper P for fixing cleaning is “3 m”, and the default blank paper transport distance D2c. Becomes “2 m”. In this case, since the white paper transport distance D1 of the roll paper P in the fixing cleaning is insufficient by “1 m”, it is necessary to change the image forming timing. Therefore, the control unit 50 sets the default white paper transport distance D2c of the roll paper P to “3 m” according to the insufficient white paper transport distance and sets the default image formation according to the extended white paper transport distance D2c. The image forming operation is executed with the start timing delayed. The image formation start timing after the change may be stored in the table TB in association with the image coverage or the like.

  In addition, when the image coverage is “120% to 240%” and the print mode is “monochrome mode”, the blank paper transport distance D2m of the default roll paper P is “0.7 m”. It is necessary to extend the blank paper conveyance distance. On the other hand, when the print mode is “color mode”, the blank paper transport distance D2c of the default roll paper P is “2 m”, and therefore, the blank paper transport distance may be increased by “1 m”. As described above, when the print mode is the “monochrome mode”, the white paper conveyance distance to be changed (extended) becomes longer than that in the “color mode”.

  In the example described above, the example using the table TB has been described, but the present invention is not limited to this. For example, the control unit 50 may calculate the image formation start timing in real time using the coverage of each acquired image, the blank transport distance D1 for fixing cleaning, and the default blank paper transport distances D2c and D2m.

[Operation Example of Image Forming System 100]
FIG. 5 is a flowchart illustrating an example of the operation of the image forming system 100 when a jam in which toner remains in the fixing unit 340 according to the second embodiment occurs. The CPU 52 of the control unit 50 executes the process shown in FIG. 5 by reading and executing a program from the ROM 54, for example. In this example, it is assumed that the print mode of the image forming system 100 is set to the color mode, and the roll paper P is set in advance in the conveyance path of the image forming system 100.

  As illustrated in FIG. 5, in step S <b> 100, the control unit 50 acquires a job transmitted from the computer 500, for example. At this time, the control unit 50 acquires coverage information of an image to be printed on the roll paper P included in the acquired job. Note that image coverage information can also be input from the operation display unit 360.

  In step S110, when the control unit 50 acquires a job from the computer 500, the control unit 50 starts printing based on the job. Specifically, the fixing unit 340 turns on the heater to heat the fixing belt and the like, and brings the fixing roller and the pressure roller into a pressure-bonded state. In addition, the control unit 50 prevents the roll paper P from being burned when the temperature of the fixing unit 340 rises, and suppresses the meandering of the roll paper P when the conveyance of the roll paper P is started or when the fixing unit 340 is pressed. Then, the conveyance (blank sheet conveyance control) of the blank roll paper P on which no image is transferred is started. When the meandering of the roll paper P converges and the fixing temperature of the fixing unit 340 rises to the set temperature, the control unit 50 starts the image forming operation by the image forming unit 310.

  In step S120, the control unit 50 determines whether or not a jam has occurred in the toner in the fixing unit 340 (affects fixing) during execution of the job. For example, when the control unit 50 determines that the roll paper P is normally conveyed based on the detection result of the paper detection unit 370, the control unit 50 continues to execute the current job on the assumption that no jam has occurred during the execution of the job. To do.

On the other hand, for example, if the control unit 50 determines that the roll paper P is not normally conveyed based on the detection result of the paper detection unit 370, it is determined in step S130 that a jam that affects fixing occurs during the execution of the job. move on. Note that the fixing state of the fixing unit 340 or the like is released due to the occurrence of a jam. In step S130, the jam processing is executed by the user or service person according to the following procedures (1) to (5).
(1) Cut one end of the roll paper P at the paper discharge port 352 of the image forming apparatus 300.
(2) The other end of the roll paper P is cut at the paper feed port 322 of the image forming apparatus 300.
(3) The cut roll paper P remaining inside the image forming apparatus 300 is pulled out from the paper discharge port 352 and the like along the paper transport direction W1.
(4) Open the door provided on the front side of the image forming apparatus 300 and check whether there is any remaining paper, glue, dirt, etc. inside the apparatus.
(5) When the confirmation is completed, the door of the image forming apparatus 300 is closed.

  In step S140, the control unit 50 determines whether or not the jam has been restored by the completion of the jam processing (1) to (5) described above. For example, the control unit 50 determines whether or not a button indicating “start fixing cleaning” displayed on the operation display unit 360 is selected. If the control unit 50 determines that the sheet has not returned from the jam, for example, if the button indicating “start of fixing cleaning” is not selected, the control unit 50 returns to step S130 and performs the jam processing (1) to (5) described above. Wait until is completed.

  On the other hand, when the control unit 50 determines that the paper has returned from the jam, for example, when the button indicating “start fixing cleaning” is selected, the process proceeds to step S150. In step S150, the control unit 50 causes the blank paper transport distance D1 of the roll paper P necessary for cleaning the toner adhering to the fixing unit 340 to exceed the preset blank paper transport distance D2c of the default roll paper P. Determine whether or not.

  For example, when the coverage of the acquired image is “120% to 240%” and the print mode is “color mode”, the control unit 50 sets “white paper conveyance distance D1 of the roll paper P for fixing cleaning” to “ 3m "is acquired from the table TB, and" 2m "is acquired from the table TB as the blank paper transport distance D2c of the default roll paper P. In this case, the control unit 50 proceeds to step S160 because the blank paper transport distance D1 of the roll paper P for fixing cleaning exceeds the blank paper transport distance D2c of the default roll paper P.

  In step S160, the control unit 50 changes the blank paper transport distance D2c of the default roll paper P. For example, when the white paper transport distance D1 of the roll paper P for fixing cleaning is “3 m” and the white paper transport distance D2c of the default roll paper P is “2 m”, the white paper transport distance of the roll paper P for fixing cleaning is D2c is insufficient by “1 m”. Therefore, the control unit 50 changes the default white paper transport distance D2c of the roll paper P from “2 m” to “3 m” extended by “1 m”. The changed blank paper transport distance D2c can be acquired from a table TB stored in association with image coverage or the like.

  In step S170, the control unit 50 resumes the printing operation. Roll paper P is set in the conveyance path of the image forming system 100. The control unit 50 performs the blank paper conveyance distance D2c changed according to the image coverage in a state where the fixing unit 340 is pressure-bonded after the jam recovery and before the image formation of the toner image on the photosensitive drum 301 is started. The white paper transport control of the roll paper P based on the above is performed. At this time, the control unit 50 controls the fixing unit 340 so that the fixing temperature of the fixing unit 340 becomes higher than the fixing temperature of the fixing unit 340 during normal printing after the roll paper P is conveyed. The fixing temperature of the fixing unit 340 during normal printing is set based on, for example, the paper type and basis weight of the roll paper P. The control unit 50 also controls to delay the image formation start timing by the exposure unit 303 as the white paper transport distance of the roll paper P is increased. Information on this image formation start timing can be acquired from the table TB.

  On the other hand, in step S150, for example, when the coverage of the acquired image is “80% to 120%” and the print mode is “color mode”, the roll paper P for fixing cleaning is used. “2 m” is acquired from the table TB as the blank paper transport distance D1 and “2 m” is acquired from the table TB as the blank paper transport distance D2c of the default roll paper P. In this case, the control unit 50 determines that it is not necessary to change the blank paper transport distance because the blank paper transport distance D1 of the roll paper P for fixing cleaning is equal to (below) the blank paper transport distance D2c of the default roll paper P. Then, the process proceeds to step S170.

  In step S170, the control unit 50 resumes the printing operation. Specifically, the control unit 50 sets a preset default roll in a state where the fixing unit 340 is pressure-bonded after the jam recovery and before the image formation of the toner image on the photosensitive drum 301 is started. The blank paper conveyance control of the roll paper P is performed for the blank paper conveyance distance D2c of the paper P. Further, the control unit 50 starts the image forming operation based on the image forming start timing by the exposure unit 303 corresponding to the default roll paper P blank paper transport distance D2c.

  As described above, according to the first embodiment, the white paper conveyance for preventing the meandering of the roll paper P after the jam recovery that affects the fixing is also used for the cleaning of the fixing unit 340. Therefore, only the fixing cleaning is performed. Therefore, the paper conveyance distance can be shortened compared with the case of conveying the white paper, and the generation of scraping paper can be reduced. In addition, it is possible to reliably prevent image smearing during fixing.

  Further, according to the first embodiment, since the fixing paper cleaning distance is changed according to the image coverage, the fixing unit 340 is cleaned in consideration of the amount of toner remaining on the fixing member. it can. For example, when the coverage of the image is high and the fixing member is very dirty, the cleaning process of the fixing unit 340 can be executed by setting the conveyance distance for fixing cleaning to be long. As a result, the fouling of the fixing unit 340 can be reliably cleaned.

  Further, according to the first embodiment, since the temperature of the fixing unit 340 at the time of controlling the conveyance of the blank paper P for fixing cleaning is set high, the toner remaining on the fixing member is more effectively removed from the blank paper. It can be fixed (attached) to the roll paper P. Thereby, since the cleaning effect can be enhanced, it is possible to reliably prevent image smearing during printing.

<Second Embodiment>
When a jam that affects fixing occurs and the image is transferred to the end of the roll paper P, if the roll paper P is pulled out of the conveyance path of the apparatus, the image on the roll paper will be out of the image range. In some cases, it protrudes and adheres to the fixing member. In such a case, when a large roll paper P is used in a subsequent job or the transport position of the roll paper P is shifted, the fixing cleaning by the white paper transport of the first embodiment described above is executed. Even so, there is a possibility that the toner adhered outside the image range of the fixing member may adhere to the roll paper P. Therefore, in the second embodiment, when the image is transferred to the end of the roll paper P and the image is transferred to the end of the roll paper P, the fixing unit 340 is moved in the axial direction of the fixing roller. The white paper conveyance control for fixing cleaning is executed after swinging. Since the configuration and operation of the other image forming system 100 are the same as those in the first embodiment, common constituent elements are denoted by the same reference numerals, and detailed description thereof is omitted.

[Functional Configuration Example of Image Forming System 100]
First, an example of a functional configuration of the image forming system 100 according to the second embodiment will be described. The image forming system 100 includes a swing mechanism 344 (broken line) in addition to the components shown in FIG. Based on the control of the control unit 50, the swing mechanism 344 reciprocates the fixing roller, the pressure roller, and the like constituting the fixing unit 340 in a direction perpendicular to the paper transport direction W1 (hereinafter referred to as the width direction W2). . In this example, the near side of the image forming apparatus 300 is referred to as an end on the near side in the width direction W2, and the far side of the image forming apparatus 300 is referred to as an end on the far side in the width direction W2. The swing mechanism 344 can be configured by, for example, a motor or a gear. Note that a known technique can be employed for the swing mechanism 344, and thus detailed description thereof is omitted.

[Operation Example of Image Forming System 100]
Next, an example of the operation of the image forming system 100 according to the second embodiment will be described. In the following description, the blank transport control for fixing cleaning (hereinafter referred to as normal fixing cleaning) described above with reference to FIG. 5 of the first embodiment is executed first. Here, the normal fixing cleaning is a process for cleaning the toner attached to the fixing member within the image range of the roll paper P, and means cleaning performed without swinging the fixing unit 340.

  The control unit 50 determines whether or not the toner image is transferred to the end portion in the width direction W2 of the roll paper P from the image data included in the acquired job when the normal paper conveyance control for fixing cleaning is completed. To do. More specifically, the toner image is transferred to one end on the near side or the far side in the width direction W2 of the roll paper P or on both the near side and the far end in the width direction W2 of the roll paper P. Determine whether or not. Note that the case where the toner image is transferred to the end includes the case where the toner image is transferred to an area other than the end of the roll paper P in the width direction W2.

  When the control unit 50 determines that the toner image is transferred to the end of the roll paper P in the width direction W2, the control unit 50 moves the fixing unit 340 in the width direction W2. For example, when the toner image is transferred to the front end of the roll paper P, the control unit 50 has a high possibility that the toner image will protrude outside the image range on the front side. Swing in direction W2. In addition, when the toner image is transferred to the back end of the roll paper P, the control unit 50 is likely to cause the toner image to protrude out of the back image range. Swing in direction W2. When the toner image is transferred to both the front side and back side ends of the roll paper P, the control unit 50 has a high possibility of the toner image protruding outside the front and back side image ranges. 340 is swung in the width direction W2 on the near side and the far side.

  Note that the swing distance of the fixing unit 340 can be determined according to, for example, the coverage of the image. Specifically, when the image coverage is classified into a plurality as shown in FIG. 3 and the image coverage is high, there is a possibility that a large amount of toner image adheres outside the image range. Set a longer distance for rocking. On the other hand, when the image coverage is low, there is a possibility that a small amount of toner image adheres to the outside of the image range. Therefore, the distance at which the fixing unit 340 is swung is set short.

  The control unit 50 swings the fixing unit 340 in the width direction W2, and then starts white paper conveyance control of the roll paper P for fixing cleaning. The white paper conveyance distance of the roll paper P can be changed according to the coverage of the image printed on the roll paper P. Specifically, as shown in FIG. 3, the higher the image coverage is, the longer the blank paper transport distance of the roll paper P is changed, and the lower the image coverage is, the shorter the white paper transport distance of the roll paper P is changed. . The blank paper conveyance distance of the roll paper P for fixing cleaning may be set to the blank paper conveyance distance D1 shown in FIG. 3, or may be set longer or shorter.

  As described above, according to the second embodiment, when the image is transferred to the end of the roll paper P, the fixing unit 340 is swung in the width direction W2, so that the image is out of the image range. Even when attached to the fixing member, the fixing unit 340 can be cleaned. Thereby, it is possible to reliably prevent image smearing of the roll paper P after a jam has occurred.

  It should be noted that the technical scope of the present invention is not limited to the above-described embodiments, and includes those in which various modifications are made to the above-described embodiments without departing from the spirit of the present invention. Although the image forming apparatus 300 shown in FIG. 1 forms a color image, the present invention is not limited to an image forming apparatus that forms a color image, and may be an image forming apparatus that forms a monochrome image.

50 Control Unit 100 Image Forming System 300 Image Forming Apparatus 301Y, 301M, 301C, 301K, 301 Photosensitive Drum (Image Carrier)
308 Intermediate transfer belt (image carrier)
310 Image forming unit 340 Fixing unit 344 Swing mechanism (moving mechanism)
D1 Blank transport distance D2, D2c, D2m of roll paper for fixing cleaning Default blank paper transport distance P of roll paper W Roll paper W1 Paper transport direction (first direction)
W2 width direction (second direction)

Claims (9)

An image forming unit for transferring a toner image formed on the image carrier onto roll paper;
A fixing unit that fixes the toner image transferred to the roll paper by the image forming unit on the roll paper;
A control unit that performs white paper conveyance control for conveying the roll paper on which the toner image is not transferred in a state where the fixing unit is pressed before the image formation of the toner image on the image carrier is started. Prepared,
In the case where a problem occurs in which unfixed toner remains in the fixing unit, the control unit performs cleaning of the fixing unit by performing the blank paper conveyance control after the recovery of the problem, and also performs the cleaning of the toner image. An image forming apparatus for changing an image formation start timing on an image carrier. The control unit is configured to carry the image carrier of the toner image when a blank paper conveyance distance of the roll paper necessary for cleaning the fixing unit exceeds a distance from an image forming start position of the image forming unit to the fixing unit. The image forming apparatus according to claim 1, wherein the image formation start timing on the body is delayed. The controller holds the image of the toner image when the blank paper conveyance distance of the roll paper necessary for cleaning the fixing unit is equal to or less than the distance from the image forming start position of the image forming unit to the fixing unit. The image forming apparatus according to claim 1, wherein the image formation start timing on the body is not changed. 4. The temperature of the fixing unit when the roll paper is transported after the failure is recovered is higher than the temperature of the fixing unit after transporting the roll paper. Image forming apparatus. A moving mechanism for moving the fixing unit in a second direction orthogonal to a first direction that is a conveyance direction of the roll paper;
When the toner image is transferred to an end portion of the roll paper in the second direction, the control unit controls the moving mechanism to move the fixing unit in the second direction to move the roll paper. The image forming apparatus according to any one of claims 1 to 4, wherein a blank paper conveyance control is performed. The control unit performs blank paper conveyance control of the roll paper in a state where the fixing unit is not moved in the second direction when the toner image is not transferred to an end portion of the roll paper in the second direction. Item 6. The image forming apparatus according to Item 5. The image forming apparatus according to claim 1, wherein the control unit controls a white paper conveyance distance of the roll paper based on a coverage of an image transferred to the roll paper. The image forming apparatus according to any one of claims 1 to 7, wherein the control unit changes a white paper conveyance distance of the roll paper depending on whether a print mode is a monochrome mode or a color mode. 9. The image forming apparatus according to claim 1, wherein when the print mode is a monochrome mode, the control unit increases the blank paper conveyance distance to be changed as compared with a case where the print mode is a color mode.

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