JP4840425B2 - Image forming apparatus - Google Patents

Description

  The present invention relates to an image forming apparatus.

  In an electrophotographic image forming apparatus used for a copying machine, a printer, a facsimile, or the like, the peripheral surface of an image carrier represented by a photosensitive drum or the like is uniformly charged, and exposure light holding image information is supplied to the image forming apparatus. An electrostatic latent image is formed on the peripheral surface of the image carrier by irradiating the peripheral surface of the image carrier, and a toner image is formed on the peripheral surface of the image carrier by developing the electrostatic latent image. The toner image is transferred directly or via, for example, an intermediate transfer member onto a sheet conveyed along the conveyance path, and the toner image is fixed on the sheet by fixing the toner image on the sheet by a fixing unit. An image composed of a toner image is formed. The paper on which the image composed of the fixed toner image is formed is further transported along the transport path and discharged to the outside of the image forming apparatus.

  In such an image forming apparatus, for example, when a paper jam occurs on the conveyance path due to a sheet being conveyed being caught by a component in the image forming apparatus, an image forming operation or a sheet conveyance is performed. Operation stops. Then, for example, the operator pulls out the apparatus assembly accommodated in the housing of the image forming apparatus so as to expose the conveyance path, and removes the paper remaining on the conveyance path due to the occurrence of a paper jam. .

  For example, when a paper jam occurs, the paper jam detection member activates a member related to paper feeding in the direction opposite to the paper feeding direction to reverse the paper, thereby removing the paper located in the transport path from the paper feeding device. A reversing mechanism of a paper feeding unit of a paper feeding device that returns to a stacking position has been proposed (for example, see Patent Document 1).

  Also, for example, when a paper jam occurs, either the upstream first sheet nipping / conveying means for nipping and conveying the sheet or the downstream second sheet nipping / conveying means for nipping and conveying the sheet There has been proposed a sheet processing apparatus and an image forming apparatus that automatically release the nipping state and send a sheet that is nipped and stopped moving to the upstream side or the downstream side by using a manual feeding unit (for example, (See Patent Document 2).

  In addition, for example, when the machine is stopped due to a paper jam that occurs outside the paper feeder, the feed clutch is turned off, the transmission of power from the drive motor to the feed roller is interrupted, and the feed roller can be freely rotated. Then, the drive motor drive is stopped after continuing for a predetermined time, the rotation of the reverse shaft driven by the drive motor is transmitted to the reverse roller via the torque limiter, and the reverse roller is driven to rotate in the counter feed direction. There has been proposed an image forming apparatus that returns a sheet sandwiched between a lever and a feed roller (see, for example, Patent Document 3).

In addition, for example, it has a pull-out member that can be pulled out from the main body. In a paper feeding device that enables paper replenishment and jamming to be performed by picking up the paper stacked and stored in the lift-up tray and feeding it to the main body one by one through the roller. A sheet feeding device provided with driving means for reversing the whirling roller by a predetermined amount, for example, a maximum length considered from the size of the paper stored in the lift-up tray when the lift-up tray is lowered, An image forming apparatus is proposed (see, for example, Patent Document 4).
JP-A 63-127933 JP-A-9-197736 JP 2004-217405 A JP 2007-22786 A

  SUMMARY OF THE INVENTION An object of the present invention is to provide an image forming apparatus that can remove paper remaining on a conveyance path without causing paper breakage or damage inside the apparatus.

The image forming apparatus according to claim 1, wherein the object is achieved.
A housing,
An image forming unit disposed in the housing, which forms a toner image and transfers the toner image onto the conveyed paper;
The toner image on the sheet is fixed on the sheet with the sheet disposed and conveyed downstream of the image forming unit in the sheet conveyance direction, and the fixing is stopped when the sheet conveyance is stopped during the fixing. A fixing device assembly configured to be freely drawn out from the housing and housed in the housing;
It is arranged downstream of the fixing device assembly in the sheet conveyance direction and adjacent to the fixing device assembly, and performs a post-fixing process on the conveyed sheet, and is configured to be pulled out from the housing. A processing device assembly housed in the housing;
When the operation is stopped, the sheet is present in an area sandwiched between a first position where the leading edge of the sheet being conveyed reaches the inlet of the processing device assembly and a second position where the completion of fixing of the sheet is guaranteed. The paper is returned to the fixing device assembly, and when the operation is stopped, the paper being transported is sandwiched between the second position and the third position where the rear edge of the paper reaches the inlet of the processing device assembly. And a control unit for advancing the sheet to be accommodated in the processing apparatus assembly when the sheet exists in the area.

Here, the image forming apparatus according to claim 2 is:
“A detector for detecting passage of the leading edge of the paper and passage of the trailing edge of the paper is provided in the fixing device assembly.
The control unit recognizes the first position and the second position by measuring a time from a first time point when the detector detects the passage of the leading edge of the paper, and the paper is detected by the detector. The third position is recognized by measuring the time from the second time point when the passage of the rear end of the vehicle is detected. "
It is characterized by that.

  According to a third aspect of the present invention, in the image forming apparatus, the processing apparatus assembly is an apparatus assembly including a cooler for cooling the sheet after fixing.

  Further, in the image forming apparatus according to claim 4, the second position is a position where the control unit guarantees completion of fixing of the maximum length paper in the transport direction among the sheets used in the image forming apparatus. It is characterized by being recognized as

  The image forming apparatus according to claim 5 is characterized in that the fixing device assembly and the processing device assembly can be pulled out from the housing only exclusively.

  According to the image forming apparatus of the first aspect, it is possible to remove the paper remaining on the conveyance path without causing paper tearing or contamination inside the apparatus.

  In addition, according to the image forming apparatus of the second aspect, it is less likely to remove the paper remaining on the conveyance path without causing the paper torn and the inside of the apparatus to be damaged as compared with the case where the present configuration is not provided. It can be realized at a cost.

  According to the image forming apparatus of the third aspect, it is possible to remove the paper remaining on the transport path without causing paper breakage or fouling of the cooler.

  According to the image forming apparatus of the present invention, even if the maximum length of the paper used in the image forming apparatus is in the transport direction, the transport path does not cause paper breakage or contamination in the apparatus. The paper remaining on the top can be removed.

  According to the image forming apparatus of the present invention, when the fixing device assembly and the processing device assembly are exclusively pulled out of the housing, the image forming device remains on the conveyance path without causing paper breakage or contamination inside the device. Used paper can be removed.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 is a schematic configuration diagram of an image forming apparatus 1 according to an embodiment of the present invention. 2 is an external perspective view of the fixing device assembly 500 and the processing device assembly 800 in the image forming apparatus 1 shown in FIG. FIG. 3 is an external perspective view of a state in which the fixing device assembly 500 shown in FIG.

  An image forming apparatus 1 shown in FIG. 1 is an image forming apparatus that employs a full-color tandem method, and each of four color toners of yellow (Y), magenta (M), cyan (C), and black (K). Using corresponding four toner image forming units arranged in parallel, each toner image forming unit forms a toner image of each color of YMCK in synchronization with feeding of an intermediate transfer belt as an intermediate medium, and the toner image of each color is The toner images are sequentially superimposed and transferred (primary transfer) on the intermediate transfer belt, and the color toner image superimposed on the intermediate transfer belt is transferred (secondary transfer) and fixed on the conveyed paper.

  As shown in FIG. 1, the image forming apparatus 1 includes a housing 100. Further, in the case 100 of the image forming apparatus 1, four toner image forming units 10Y, 10M, 10C, and 10K and four primary transfer rolls 20Y, 20M, 20C, and 20K are provided. Further, in the casing 100 of the image forming apparatus 1, a peripheral surface that is stretched around the drive roll 31, the driven roll 32, the tension roll 33, and the backup roll 42 and circulates in the counterclockwise arrow A direction. A semiconductive intermediate transfer belt 30 formed, a batch transfer device 40 for performing secondary transfer, a fixing device 50 for fixing an unfixed toner image on a sheet, a cooler 80 for cooling the sheet after fixing, and the intermediate transfer belt 30 A belt cleaning device 34 for cleaning residual toner remaining on the belt is also provided.

  The four toner image forming units 10Y, 10M, 10C, and 10K are arranged side by side in the circulating movement direction of the intermediate transfer belt 30, and each toner image forming unit 10Y, 10M, 10C, and 10K has a clockwise arrow. There are provided photosensitive drums 11Y, 11M, 11C, and 11K that form an electrostatic latent image on the peripheral surface while rotating in the B direction and hold the electrostatic latent image. The peripheral surfaces of the photosensitive drums 11Y, 11M, 11C, and 11K are in contact with the intermediate transfer belt 30. The primary transfer rolls 20Y, 20M, 20C, and 20K are disposed at respective locations facing the respective four photosensitive drums 11Y, 11M, 11C, and 11K surrounded by the intermediate transfer belt 30. A portion where the body drums 11Y, 11M, 11C, and 11K are in contact with the intermediate transfer belt 30 is a primary transfer region.

  Further, around the toner image forming units 10Y, 10M, 10C, and 10K, developing device main bodies 12Y, 12M, 12C, and 12K provided with developing rolls 121Y, 121M, 121C, and 121K, and exposure light irradiation devices 17Y and 17M are provided. , 17C, 17K, non-contact charging devices 13Y, 13M, 13C, 13K, and drum cleaning devices 14Y, 14M, 14C, 14K.

  The developing device main bodies 12Y, 12M, 12C, and 12K are arranged around the photosensitive drums 11Y, 11M, 11C, and 11K, and are upstream of the rotation of the photosensitive drums 11Y, 11M, 11C, and 11K with respect to the primary transfer region. Has been deployed. Each developing device main body 12Y, 12M, 12C, 12K contains toner inside that is replaceable by being pulled out in the axial direction of the developing device main bodies 12Y, 12M, 12C, 12K with respect to the main body of the image forming apparatus 1. The toner cartridges 15Y, 15M, 15C and 15K thus mounted are detachably mounted. Each of the developing device main bodies 12Y, 12M, 12C, and 12K includes reserve tanks 16Y, 16M, 16C, and 16K that temporarily store toner, and the mounted toner cartridges 15Y, 15M, 15C, and 15K. The toner contained in the toner is supplied to the developing device main bodies 12Y, 12M, 12C, and 12K through reserve tanks 16Y, 16M, 16C, and 16K.

  The exposure light irradiation devices 17Y, 17M, 17C, and 17K are disposed further upstream than the developing device bodies 12Y, 12M, 12C, and 12K. Further, the non-contact charging devices 13Y, 13M, 13C, and 13K are arranged further upstream than the exposure light irradiation devices 17Y, 17M, 17C, and 17K.

  The drum cleaning devices 14Y, 14M, 14C, and 14K are arranged around the photosensitive drums 11Y, 11M, 11C, and 11K, and are downstream in the rotation of the photosensitive drums 11Y, 11M, 11C, and 11K with respect to the primary transfer region. In the primary transfer region, residual toner remaining on the photosensitive drums 11Y, 11M, 11C, and 11K that is not transferred to the intermediate transfer belt 30 is cleaned with a conductive brush and blade (not shown).

  As shown in FIGS. 1 to 3, the fixing device 50 is provided in a fixing device assembly 500 that is configured to be freely pulled out from the housing 100 and accommodated in the housing 100. The fixing device 50 fixes the toner image on the sheet onto the sheet with the sheet disposed and conveyed downstream of the secondary transfer region in the sheet conveyance direction. In the fixing device assembly 500, a detector 53 that detects the passage of the leading end of the sheet after fixing and the passage of the trailing end of the sheet is connected to the fixing device 50 on the downstream side of the fixing device 50 in the sheet transport direction. Adjacent to each other. The fixing device 50 provided in the fixing device assembly 500 stops fixing when the sheet conveyance is stopped during fixing.

  As shown in FIGS. 1 to 3, the cooler 80 is provided in a processing apparatus assembly 800 that is configured to be drawable from the casing 100 and is accommodated in the casing 100. The processing device assembly 800 is disposed downstream of the fixing device assembly 500 in the paper transport direction and adjacent to the fixing device assembly 500, and a cooler 80 provided in the processing device assembly 800 is transported by the processing device assembly 800. The sheet after fixing is cooled.

  Note that the fixing device assembly 500 and the processing device assembly 800 can be pulled out of the housing 100 only exclusively.

  The belt cleaning device 34 is provided around the intermediate transfer belt 30 and is provided downstream of the secondary transfer region in the circulating movement direction of the intermediate transfer belt 30. This belt cleaning device 34 includes a cleaning roll 341, and residual toner remaining on the intermediate transfer belt 30 that is not transferred onto the sheet in the secondary transfer region is cleaned by the cleaning roll 341.

  In addition, the image forming apparatus 1 includes a control unit 90.

  In the image forming apparatus 1, the control unit 90 causes an image forming operation in which a paper jam occurs, for example, a paper jam occurs on a transport path due to a paper being transported being caught by a component in the image forming apparatus. When the sheet conveyance operation is stopped, the sheet remaining on the conveyance path in a state straddling between the fixing device assembly 500 and the processing device assembly 800 is returned to the fixing device assembly or the processing device assembly. Control whether to advance into the body.

  Hereinafter, image formation when the image forming apparatus 1 shown in FIG. 1 is operated will be described.

  The peripheral surfaces of the photoconductive drums 11Y, 11M, 11C, and 11K are uniformly negatively charged by the non-contact charging devices 13Y, 13M, 13C, and 13K. On the peripheral surfaces of the photosensitive drums 11Y, 11M, 11C, and 11K that are uniformly negatively charged by the non-contact type charging devices 13Y, 13M, 13C, and 13K, images are applied from the exposure light irradiation devices 17Y, 17M, 17C, and 17K. The laser beam holding the information is irradiated to form electrostatic latent images on the circumferential surfaces of the photosensitive drums 11Y, 11M, 11C, and 11K. The developing device main bodies 12Y, 12M, 12C, and 12K adopt a two-component developing system. The developing device main bodies 12Y, 12M, 12C, and 12K include a magnetic carrier and toner cartridges 15Y, 15M, 15C, and 15K. And a two-component developer composed of negatively charged toner supplied through the reserve tanks 16Y, 16M, 16C, and 16K. On the peripheral surfaces of the developing rolls 121Y, 121M, 121C, and 121K provided in the developing device main bodies 12Y, 12M, 12C, and 12K, there is a developer layer (so-called magnetic layer) in which a magnetic carrier to which toner is attached is layered. The formed negatively charged toner is rotated around the developing rolls 121Y, 121M, 121C, and 121K, so that the photosensitive drums 11Y, 11M, 11C, and 11K around which the electrostatic latent images are held from the developer layer are rotated. Supplied to the surface. The electrostatic latent images formed on the peripheral surfaces of the photoconductor drums 11Y, 11M, 11C, and 11K are developed by being supplied with negatively charged toner and become toner images.

  The primary transfer rolls 20Y, 20M, 20C, and 20K are applied with a positive transfer bias having a polarity opposite to the polarity of the toner, and are formed on the peripheral surfaces of the photosensitive drums 11Y, 11M, 11C, and 11K. The toner images are transferred from the peripheral surfaces of the photoconductive drums 11Y, 11M, 11C, and 11K to the peripheral surface of the intermediate transfer belt 30. The toner images formed by the toner image forming units 10 </ b> Y, 10 </ b> M, 10 </ b> C, and 10 </ b> K become color toner images that overlap one on the intermediate transfer belt 30.

  The batch transfer device 40 is provided on the toner image holding surface side of the intermediate transfer belt 30 and in contact with the secondary transfer roll 41 provided with pressure, and on the back side of the intermediate transfer belt 30. A backup roll 42 is provided, and the intermediate transfer belt 30 is sandwiched between these two rolls 41 and 42. A space between these two rolls 41 and 42 becomes a secondary transfer region.

  Further, as shown in FIG. 1, the image forming apparatus 1 is provided with a paper tray 60, and the paper stored in the paper tray 60 is sent to the secondary transfer region at a predetermined timing. In the secondary transfer area, the color toner images overlapped on the intermediate transfer belt 30 are transferred onto the fed paper.

  Further, the image forming apparatus 1 is provided with four conveyor belts 70 that convey the sheet on which the color toner image is secondarily transferred, and the sheet conveyed by the four conveyor belts 70 is the fixing device assembly. It is sent to the fixing device 50 provided in 500. The fixing device 50 includes a fixing roll 51 having a heating mechanism 511 and a pressure roll 52 provided so as to face the fixing roll 51. When the paper that has passed through the secondary transfer region is conveyed between the fixing roll 51 and the pressure roll 52 facing each other, the toner constituting the color toner image on the paper is transferred by the heating mechanism 511 of the fixing roll 51. It is melted and fixed on a sheet, and an image composed of a fixed toner image is formed on the sheet. A detector 53 provided adjacent to the fixing device 50 and downstream of the fixing device 50 in the paper transport direction detects passage of the leading edge of the paper after fixing and passage of the trailing edge of the paper.

  In addition, in the fixing device assembly 500 of the image forming apparatus 1, a conveyance belt 71 that conveys the paper after fixing is provided, and the paper conveyed by the conveyance belt 71 is provided in the processing device assembly 800. To the cooler 80. When the fixed sheet is conveyed to the processing apparatus assembly 800, the sheet is cooled by a cooler 80 provided in the processing apparatus assembly 800. As a result, the melted toner on the paper is solidified.

  Further, after the toner images formed on the peripheral surfaces of the photoconductive drums 11Y, 11M, 11C, and 11K move to the peripheral surface of the intermediate transfer belt 30 in the primary transfer region, the photoconductor drums 11Y, 11M, 11C, and 11K Residual toner remaining in is cleaned with a conductive brush and a blade (not shown) arranged in the drum cleaning devices 14Y, 14M, 14C, and 14K.

  The residual toner remaining on the intermediate transfer belt 30 after the overlapping color toner images on the intermediate transfer belt 30 are transferred onto the paper in the secondary transfer region is disposed in the belt cleaning device 34. Cleaning is performed by the cleaning roll 341.

  The description of the image formation when operating the image forming apparatus 1 shown in FIG. 1 is finished, and the control operation by the control unit 90 will be described in detail below.

  FIG. 4 is a time chart for explaining the control operation by the control unit 90.

  The control unit 90 measures the time from the first time point when the passage of the leading edge of the sheet is detected by the detector 53, thereby the first position where the leading edge of the sheet being conveyed reaches the inlet of the processing apparatus assembly 800, Then, the second position where the completion of fixing of the maximum length paper in the transport direction among the sheets used in the image forming apparatus 1 is recognized is recognized. In addition, the control unit 90 measures the time from the second time point when the passage of the trailing edge of the sheet is detected by the detector 53, so that the third position at which the trailing edge of the sheet reaches the inlet of the processing apparatus assembly 800. Recognize

  Note that “T1” shown in FIG. 4 is obtained by dividing the distance on the conveyance path between the detector 53 and the inlet of the processing apparatus assembly 800 by the conveyance speed, and the leading edge or trailing edge of the sheet being conveyed. Represents the time required to pass the distance. Further, “T2” shown in FIG. 4 indicates the leading edge of the sheet being conveyed or the sheet obtained by dividing the distance on the conveyance path between the inlet of the processing apparatus assembly 800 and the second position by the conveyance speed. It represents the time required for the trailing edge to pass that distance.

  In the image forming apparatus 1, when a paper jam occurs and the image forming operation and the paper transporting operation are stopped (hereinafter, such time is referred to as operation stop time), the control unit 90 recognizes the first position. In other words, before the time from the first time point when the passage of the leading edge of the sheet is detected by the detector 53 reaches “T1”, the leading edge of the sheet has not reached the inlet of the processing apparatus assembly 800, and the sheet Is present in the fixing device assembly 500, so that the sheet is stopped without moving.

  When the operation is stopped, the controller 90 recognizes the first position before the second position is recognized, that is, from the first time point when the detector 53 detects the passage of the leading edge of the sheet. After the time reaches “T1”, before the time reaches “T1 + T2”, that is, when the paper is present in the area sandwiched between the first position and the second position, the leading edge of the paper is the processing device. The sheet that has entered the assembly 800 but has not yet been fixed and has an unfixed area remains on the transport path in a state of straddling between the fixing device assembly 500 and the processing device assembly 800. The control unit 90 returns the sheet into the fixing device assembly 500.

  When the operation is stopped, the controller 90 recognizes the second position and then recognizes the third position, that is, from the first time point when the detector 53 detects the passage of the leading edge of the sheet. After the time reaches “T1 + T2”, the time from the second point in time when the passage of the trailing edge of the sheet is detected by the detector 53 is reached before the time reaches “T1”, that is, the second position and the third position. When the sheet exists in the sandwiched area, the sheet that has been fixed but the rear end of the sheet does not enter the cooling device straddles between the fixing device assembly 500 and the processing device assembly 800. Since the sheet remains on the conveyance path in the state, the control unit 90 advances the sheet and stores it in the processing apparatus assembly 800.

  When the operation is stopped, the time after the third position is recognized by the control unit 90, that is, the time from the second time point when the passage of the trailing edge of the paper is detected by the detector 53 has reached "T1". After that, the trailing edge of the sheet enters the cooling device, and the sheet exists in the processing apparatus assembly 800, so that the sheet is stopped without moving.

  As described above, according to the image forming apparatus 1 of the present embodiment, the conveyance path in a state where the sheet straddles between the fixing device assembly 500 and the processing device assembly 800 by the control operation of the control unit 90. Therefore, the operator pulls out the fixing device assembly 500 or the processing device assembly 800 that can be pulled out only exclusively from the housing 100 to expose the conveyance path, thereby causing paper breakage. The paper remaining on the transport path can be removed without any trouble.

  Further, according to the image forming apparatus 1 of the present embodiment, the sheet in which the unfixed area is present is returned into the fixing device assembly 500 by the control operation of the control unit 90, and thus the sheet is transported without causing the cooler to become dirty. Paper remaining on the path can be removed.

  Further, according to the image forming apparatus 1 of the present embodiment, the control unit 90 measures the time from the first time point when the passage of the leading edge of the paper is detected by the detector 53, thereby the first position, the first position. Since the position 2 and the third position are recognized, it is less likely to remove paper remaining on the conveyance path without causing paper breakage or contamination in the apparatus, as compared with the case where this configuration is not provided. It can be realized at a cost.

  Further, according to the image forming apparatus 1 of the present embodiment, the control unit 90 sets the second position at which the completion of fixing of the maximum length paper in the transport direction among the sheets used in the image forming apparatus 1 is guaranteed. Since it is recognized as a position, even if it is the maximum length paper in the transport direction among the paper used in the image forming apparatus 1, the paper remaining on the transport path without causing paper breakage or contamination in the apparatus Can be removed.

  In the above-described embodiment, the example in which the image forming apparatus of the present invention is an image forming apparatus adopting the full-color tandem method has been described. However, the present invention is not limited to this, and the image forming unit and the fixing unit are not limited thereto. Any type of image forming apparatus may be used as long as the image forming apparatus includes an apparatus assembly and a processing apparatus assembly.

  In the above-described embodiment, the example in which the processing device assembly is a device assembly including a cooler that cools the sheet after fixing has been described. However, the processing device assembly according to the present invention is not limited to this. Any device assembly may be used as long as it is a device assembly that performs a post-fixing process on the conveyed paper.

  Further, in the above-described embodiment, the example in which the fixing device assembly and the processing device assembly can be pulled out exclusively from the casing has been described. However, the fixing device assembly and the processing device assembly according to the present invention are described. Is not limited to this.

1 is a schematic configuration diagram of an image forming apparatus 1 according to an embodiment of the present invention. FIG. 2 is an external perspective view of the fixing device assembly 500 and the processing device assembly 800 in the image forming apparatus 1 shown in FIG. FIG. 3 is an external perspective view of a state in which the fixing device assembly 500 shown in FIG. 6 is a time chart for explaining a control operation by a control unit 90.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Image forming apparatus 100 Case 10Y, 10M, 10C, 10K Toner image forming unit 11Y, 11M, 11C, 11K Photosensitive drum 12Y, 12M, 12C, 12K Developing device main body 121Y, 121M, 121C, 121K Developing roll 13Y, 13M , 13C, 13K Non-contact charging device 14Y, 14M, 14C, 14K Drum cleaning device 15Y, 15M, 15C, 15K Toner cartridge 16Y, 16M, 16C, 16K Reserve tank 17Y, 17M, 17C, 17K Exposure light irradiation device 20Y, 20M, 20C, 20K Primary transfer roll 30 Intermediate transfer belt 31 Drive roll 32 Driven roll 33 Tension roll 34 Belt cleaning device 341 Cleaning roll 40 Batch transfer device 41 Secondary transfer roll 42 Bar Click-up roll 50 fixing device 51 fixing roller 511 heating mechanism 52 pressure roll 53 detector 500 fixing assembly 60 paper tray 70, 71 the conveyor belt 80 cooler 800 processor assembly 90 control unit

Claims (5)

A housing,
An image forming unit disposed in the casing, which forms a toner image and transfers the toner image onto the conveyed paper;
The toner image on the sheet is fixed on the sheet with the sheet arranged and conveyed downstream of the image forming unit in the sheet conveyance direction, and the fixing is stopped when the sheet conveyance is stopped during fixing. A fixing device assembly configured to be freely drawn out from the housing and housed in the housing;
It is arranged downstream of the fixing device assembly in the paper conveyance direction and adjacent to the fixing device assembly, and performs a post-fixing process on the conveyed paper so that it can be pulled out from the housing. and a processor assembly該筐housed in the body,
The image forming unit transfers the toner image onto the paper, fixes the toner image on the paper in the fixing device assembly, the leading edge of the paper enters the processing device assembly, and the rear of the paper. An image in which the completion of fixing of the paper is guaranteed at the first timing when the paper is straddled between the fixing device assembly and the processing device assembly before the end reaches the processing device assembly entrance. A forming device,
The leading end of the sheet in feed transportable reaches the processing assembly inlet, the paper is the fixing assembly and the second and subsequent timings start spans between the processor assembly and the the paper fixing completion When the operation is stopped before the guaranteed first timing, the sheet is returned to the fixing device assembly , and after the first timing at which the completion of fixing of the sheet is guaranteed , the trailing edge of the sheet is the processing device. When the operation stops before the third timing at which the sheet straddling between the fixing device assembly and the processing device assembly reaches the entrance of the assembly and stops, the paper is advanced and accommodated in the processing device assembly. An image forming apparatus comprising: a control unit that controls the image forming apparatus. A detector for detecting passage of the leading edge of the paper and passage of the trailing edge of the paper in the fixing device assembly;
The control unit recognizes the second timing and the first timing by measuring the time from the first time the passage of the leading end of the sheet is detected by the detector, the paper by the detector The image forming apparatus according to claim 1, wherein the third timing is recognized by measuring a time from a second time point when the passage of the rear end of the rear end is detected.   The image forming apparatus according to claim 1, wherein the processing apparatus assembly is an apparatus assembly including a cooler that cools a sheet after fixing. Wherein said control unit, characterized in that the timing of completion of the fixing of the conveying direction maximum length of the sheet of paper used in the image forming apparatus is ensured is to recognize as the first timing Item 4. The image forming apparatus according to any one of Items 1 to 3. 5. The image forming apparatus according to claim 1, wherein the fixing device assembly and the processing device assembly can be pulled out exclusively from the housing. 6.

Images