JP2017003768A - Image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problem in which: sheets in an apparatus are discarded and wasted to solve paper jam; a device collecting sheets after the occurrence of paper jam has an increased size.SOLUTION: An image forming apparatus has a retreat conveyance path 1 retreating sheets arranged on an extension line from a reverse conveyance path 2, and has the retreat conveyance path 1 connected to a conveyance path upstream an image forming part 13. After the occurrence of paper jam, the image forming apparatus retreats sheets on the retreat conveyance path 1, and after the paper jam is solved, conveys the sheet retreated on the retreat conveyance path 1 to resume an operation of image formation.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an image forming apparatus that forms an image on a sheet.

  Conventionally, when an abnormality such as a sheet jam occurs in an image forming apparatus, the operation of the apparatus is generally stopped when the sheet jam occurs, and an operator performs a sheet jam process.

  In order to eliminate waste of a sheet when a sheet jam occurs, a sheet collecting unit is provided in the middle of a conveyance path or in a discharge unit to collect a usable sheet (Patent Document 1). In this proposal, after the sheet jamming process, the sheet is fed from the sheet collecting unit and the image forming operation is resumed.

JP 2008-20729 A

  When a sheet that can be used in the sheet collecting unit in the apparatus is retracted when an abnormality such as a sheet jam occurs, there is a problem of an increase in size. In the case of the sheet collection unit described in Patent Document 1, since a sheet collection unit that branches from the conveyance path is provided, a dedicated sheet guide component (such as a switching flapper) for guiding sheet paper to the sheet collection unit is necessary. is there. Since there is a dedicated part for guiding the sheet to the sheet collecting unit, the apparatus becomes large.

  In order to solve the above problems, an image forming apparatus according to the present invention guides an image forming unit that forms an image on a sheet, and a sheet that is conveyed in a first direction after the image is formed by the image forming unit. In addition, the sheet guided in the first direction is connected to the reversal conveyance path that guides the sheet when reversed in the second direction opposite to the first direction and the reversal conveyance path, and an abnormality has occurred. A retreat conveyance path for receiving a sheet sent in the first direction from the reversal conveyance path.

  According to the configuration of the present invention, an increase in size of the apparatus can be prevented while suppressing waste of the sheet.

1 is a schematic cross section of an image forming apparatus according to the present embodiment. 1 is a schematic diagram of an image forming apparatus of the present embodiment. It is explanatory drawing for demonstrating the paper conveyance operation | movement of single-sided image formation and double-sided image formation. It is the schematic showing the operation | movement at the time of sheet | seat jamming by FD discharge | emission of the single side | surface concerning this Embodiment. It is the schematic showing the operation | movement at the time of sheet | seat clogging by the double-sided image formation in connection with this Embodiment. FIG. 10 is a schematic diagram illustrating an operation when a sheet jam occurs in the discharge tray. 6 is a flowchart of an operation associated with occurrence of a sheet jam related to the present embodiment. It is a control block diagram.

  FIG. 1 is a schematic sectional view of an image forming apparatus 100 according to an embodiment of the present invention.

  The image forming apparatus 100 includes a feeding unit 12 that feeds sheets one by one sequentially. The sheet fed from the feeding unit 12 is conveyed to the image forming unit 13 by a feeding conveyance unit 91 including the registration unit 11.

  The image forming unit 13 includes a photosensitive drum 7 that forms a developer image with a developer. The image forming unit 13 forms an image on the sheet while conveying the sheet by a known electrophotographic method.

  A fixing unit 6 that fixes the toner image on the sheet is provided downstream of the image forming unit 13 in the transport direction.

  A discharge conveyance unit 92 including a discharge conveyance path 8 for discharging the sheet as it is is provided downstream of the fixing unit 6 in the conveyance direction. Below the discharge conveyance path 8 is provided a reverse conveyance unit 93 that reverses (switches back) and conveys the sheet. The reverse conveyance unit 93 includes a vertical conveyance path 21 that guides the sheet sent from the fixing unit 6 downward, and a reverse conveyance path 2 that is connected to the vertical conveyance path 21 and into which the reversed sheet is temporarily pulled. . Specifically, the reverse conveyance path 2 guides a sheet that is sent from the vertical conveyance path 21 and is conveyed to the right in FIGS. Thereafter, the reverse conveyance path 2 guides the sheet when the sheet is reversed and conveyed so as to go to the left in FIGS. 1 and 2, which is the second direction opposite to the first direction.

  The reversing conveyance unit 93 is for reversing and conveying the sheet in the reversing discharge conveying path 10 that joins the discharge conveying path 8 to discharge the reversed sheet to the outside of the apparatus, and the conveying paths 21, 2, and 10. A reverse conveying means such as a conveying roller is provided.

  Below the image forming unit 13, there is provided a double-sided conveyance unit 94 that conveys the sheet reversed by the reverse conveyance unit 93 in order to form images on both sides. The double-sided conveyance unit 94 includes a double-sided conveyance path 3 as a re-conveyance path for conveying the inverted sheet to the upstream side of the registration unit 11 for double-sided image formation.

  As shown in FIG. 2, the image forming apparatus 100 includes a retreat conveyance unit 95 for retreating a sheet that has been fixed by the fixing unit 6 when a sheet jam occurs. The evacuation conveyance unit 95 includes the evacuation conveyance path 1 disposed on an extension line of the reverse conveyance path 2. That is, the retreat conveyance path 1 is directly connected to the reversal conveyance path 2 so as to receive the sheet sent in the first direction (rightward in FIG. 2) in the reversal conveyance path 2.

  Further, the retreat conveyance path 1 is also connected to the upstream side of the registration unit 11. That is, one end of the retreat conveyance path 1 is connected to the reverse conveyance path 2, and the other end of the retraction conveyance path 1 is connected to the feeding conveyance section 91. The retreat conveyance unit 95 can convey the sheet in the retreat conveyance path 1 in both directions, that is, the normal conveyance direction toward the feeding conveyance unit 91 and the reverse conveyance direction toward the reverse conveyance path 2.

  FIG. 8 is a control block diagram of the image forming apparatus 100. The control unit 99 is connected to the sensors SN arranged in each conveyance path shown in FIGS. A signal from a sensor SN that detects a sheet in each conveyance path is input to the control unit 99, and the control unit 99 determines the occurrence of an abnormality such as a jam (jam) of the sheet and the occurrence location. In this way, the control unit 99 and the sensor SN constitute a detection unit that detects an abnormality of the apparatus.

  The control unit 99 is connected to the image forming unit 13 and the fixing unit 6, and the control unit 99 controls operations of the image forming unit 13 and the fixing unit 6. Further, a feeding conveyance unit 91, a discharge conveyance unit 92, a reverse conveyance unit 93, a double-side conveyance unit 94, and a retreat conveyance unit 95 are connected to the control unit 99. The control unit 99 controls sheet operations of the feeding conveyance unit 91, the discharge conveyance unit 92, the reverse conveyance unit 93, the double-side conveyance unit 94, and the retreat conveyance unit 95. The control unit 99 is connected to an operation panel 98 for an operator to input mode settings for image formation. On the operation panel 98, guidance (display) for guiding the operation to the operator is also performed by the control unit 99.

  The control unit 99 controls the operations of the image forming unit 13 and the conveying units 91, 92, 93, 94, and 95 according to the signal from the sensor SN if the RAM is used as a work area in accordance with the program recorded in the ROM. . Hereinafter, the operation of the control unit 99 will be described.

  First, a normal sheet conveyance operation (when no sheet jam occurs) will be described with reference to FIG.

  In the mode in which image formation is performed on one side, face-up discharge (FU discharge) in which the image forming surface is up when discharging out of the image forming apparatus and face-down discharge (FD discharge) in which the image forming surface is down There are two types of discharge methods.

  In the case of FU discharge, the sheet on which the toner image is fixed by the fixing unit 6 is conveyed to the discharge conveyance path 8, and the discharge conveyance unit 92 is discharged to the outside as it is (see FIG. 3A).

  In the case of FD discharge, the reverse conveyance unit 93 conveys the sheet on which the toner image is fixed by the fixing unit 6 to the vertical conveyance path 21 and the reverse conveyance path 2. Thereafter, the reverse conveyance unit 93 is switched back with the conveyance direction reversed, and discharged through the reverse discharge conveyance path 10 (see FIG. 3B).

  In the case of double-sided image formation, the sheet on which the first-side toner image has been fixed is conveyed to the vertical conveyance path 21 and the reverse conveyance path 2 and switched back. And the reverse conveyance part 93 conveys a sheet | seat to the double-sided conveyance path 3 (refer FIG.3 (c)). Thereafter, the sheet is conveyed from the double-sided conveyance path 3 to the upstream side of the registration unit 11, and the image formation unit 13 and the fixing unit 6 form the second image. The sheet with the images formed on both sides is conveyed to the discharge conveyance path 8 and discharged outside the apparatus.

  Hereinafter, the operation when a sheet jam occurs will be described for each image forming mode, using the flowcharts of FIGS. 4 to 6 and FIG. In FIGS. 4 to 6, for the sake of explanation, numbers corresponding to the order in which the sheets are discharged out of the apparatus are given in the vicinity of each sheet.

  In the case of FU discharge for forming an image on one side, a sheet positioned on the downstream side in the conveying direction from the place where the sheet is jammed is discharged outside the apparatus.

  However, in the case of FU discharge in which an image is formed on one side and the sheet is jammed in the discharge tray of the image forming apparatus 100 (not shown), the operation will be described below with reference to FIG. To do. Note that the same operation is performed when a post-processing apparatus that post-processes a sheet discharged by the image forming apparatus is mounted on the image forming apparatus and the sheet is jammed in the post-processing apparatus. In FIG. 6, it is assumed that the first sheet is jammed in the discharge tray, and the second and subsequent sheets fed subsequently are in the image forming apparatus 100. When the first sheet is jammed, the second sheet (2) positioned in the discharge conveyance path 8 is conveyed out of the image forming apparatus 100 as shown in FIG. 6B. . The third sheet (3) fixes the toner image, conveys it to the retreat conveyance path 1, and retreats (stops) the retreat conveyance path 1. In this state, the operator processes (removes) sheets other than the sheet (3) retreated to the retreat conveyance path 1. FIG. 6C shows a state after the operator processes the sheet.

  Next, as shown in FIG. 6D, image formation is performed on the first sheet and the second sheet (2) that have been subjected to the sheet jamming process in the discharge tray or the post-processing apparatus. That is, new feeding is performed from the feeding unit 12 and an image is formed on the fed sheet. Thereafter, the third sheet (3) evacuated to the evacuation conveyance path 1 is conveyed to the upstream side of the registration unit 11, and is discharged through the image forming unit 13, the fixing unit 6, and the discharge conveyance path 8. The By conveying the sheet to the upstream side of the registration unit 11, the front and back of the sheet on which the image has been formed can be discharged as requested. Note that since the image has already been formed on the third sheet (3) that has been retracted in the retracting conveyance path 1, the image forming unit 13 does not form a toner image.

  Also in the case of FD discharge for forming an image on one side, if a sheet jam occurs in the image forming apparatus as in the case of FU discharge, the sheet on the downstream side in the transport direction from the place where the sheet jam occurs is removed from the machine. To discharge. However, in the case of FU discharge in which an image is formed on one side and the sheet is jammed in the discharge tray of the image forming apparatus 100, the operation will be described below with reference to FIG. The same operation is performed when a sheet jam occurs in a post-processing apparatus that post-processes a sheet discharged by the image forming apparatus. If a sheet jam occurs in the state of FIG. 4A, the second sheet (2) on which image formation has been completed is conveyed to the retreat conveyance path 1 and retreated as shown in FIG. 4B. In this state, the operator processes (removes) sheets other than the second sheet (2) retreated to the retreat conveyance path 1. FIG. 4C shows a state after the operator processes the sheet.

  After the sheet clogging process, image formation is performed on one sheet (1) that has been clogged in the discharge tray or the post-processing apparatus. That is, a new sheet is fed from the feeding unit 12 to form an image on the fed sheet, and then the third sheet (3) is fed (see FIG. 4D). After reversing the first sheet (1), the second sheet (2) that has been retreated to the retreat conveyance path 1 is conveyed toward the discharge port via the reversal conveyance path 2 and the vertical conveyance path 21. (See FIG. 4E). Then, the second sheet (2) is discharged out of the apparatus following the first sheet (1).

  Next, an operation when a sheet is jammed in the case of double-sided image formation will be described. In the example shown in FIG. 5A, the first sheet (1) is fixing the image on the second side, and the second sheet (2) is before the image formation on the second side. It is. The third sheet (3) is reversely conveyed in the reverse conveyance path 2 toward the second surface after the fixing of the image on the first surface, and the fourth sheet (4) is in the first surface. The image is being formed. The fifth sheet (5) is after being fed and before image formation. Here, in the state shown in FIG. 5A, when a sheet jam occurs in the second sheet (2), the third sheet (3) being reversed is conveyed to the retreat conveyance path 1 and retreated. . At this time, the first sheet (1) on the downstream side of the sheet jamming point and on which both sides of the image can be formed is discharged out of the apparatus, and the state shown in FIG. In this state, the operator processes (removes) the sheets other than the sheet (3) and the fifth sheet (5) retreated to the retreat conveyance path 1. FIG. 5C shows a state after the operator processes the sheet.

  When the process of removing the sheet is completed, the image formation is resumed, but the fifth sheet (5) is in an available state before the image formation. Therefore, when restarting, the fifth sheet (5) forms an image as the second sheet (2) (see FIG. 5D). After the image formation on the first surface of the second sheet (2) is completed, the second sheet (2) is reversed and conveyed, and the second sheet that has been reversed and conveyed is conveyed to the duplex conveyance path 3. That is, the second sheet (2) is reversely conveyed on the reverse conveyance path 2 while the third sheet (3) is stopped on the retreat conveyance path 1. The sheet (3) retreated to the retreat conveyance path 1 is conveyed to the double-sided conveyance path 3 so as to follow the second sheet (2). Here, during that time, image formation on the first side of the fourth sheet (4) that has been removed due to sheet jamming is performed on the newly fed sheet (see FIG. 5E). By the above operation, it is possible to return to the state before the sheet is jammed.

  Further, when a sheet jam occurs in the discharge tray or the post-processing apparatus in the duplex mode, the operation is performed as follows. That is, when a sheet on which both sides of the image have been formed is retreated in the retreat conveyance path 1, the sheet is conveyed upstream of the registration unit 11, rotated forward, and discharged through the image forming unit 13. If the retracted sheet has an image formed on only one side, as shown in FIG. 5, the sheet retracted to the retracted transport path 1 is transported back to the image forming unit 13 to form an image on the second surface. To do.

  As described above, when a sheet jam occurs in the image forming apparatus 100, the image forming apparatus 100 is operated as follows. After the control unit 99 confirms that no sheet jam has occurred in the fixing unit 6, the discharge conveyance path 8, and the reversal conveyance path 2, the image-formed sheet is conveyed to the retreat conveyance path 1 and retreated there. (Stop). After the sheet is retreated to the retreat conveyance path 1, the operator is caused to process a sheet other than the sheet in the retreat conveyance path 1, and then the conveyance of the sheet in the retreat conveyance path 1 is resumed.

  Here, in the present embodiment, only one sheet on which an image has been fixed is retracted when a sheet jam occurs, and the sheet retracted at the time of resumption is used. Here, in the case of a sheet jam in the image forming apparatus, there is a possibility that the image forming process may be delayed due to the sheet jam when the sheet is jammed. In this case, since it is expected to affect the image, in the present embodiment, only one sheet is retracted.

  More specifically, first, in the case of single-sided image formation, when a sheet jam occurs in the image forming apparatus, the sheet downstream from the location where the sheet jam has occurred is normally discharged as described above, and the retreat conveyance path Do not evacuate to 1. In the case of double-sided image formation, when a sheet jam occurs in the state shown in FIG. 5, the third sheet (3) that is being reversed is retracted. On the other hand, the fourth sheet (4) during image formation may have an effect on the image such as an image shock due to the sheet clogging. Therefore, the fourth sheet (4) is removed by the operator by the sheet clogging process.

  Further, when sheet jam occurs in a state where the double-sided image formation is slightly advanced from the state of FIG. 5A, the following is performed. That is, when the third sheet (3) has been reversed and is in the duplex conveying path 3, the first sheet (1) is being discharged, and the fourth sheet (4) is being fixed. In the following way: Only the fourth sheet (4) is retreated to the retreat conveyance path 1. Since the upstream side of the fourth sheet (4) is in the process of image formation, it is removed because there is an effect on the image due to sheet jamming. When a sheet jam occurs in the image forming apparatus 100 as described above, the sheet being reversed or fixed may be retracted. Therefore, in this embodiment, the number of sheets to be retracted is one.

  FIG. 7 is a flowchart showing an operation associated with occurrence of a sheet jam in the image forming apparatus. The control unit 99 controls the operations of the image forming unit 13 and the conveying units 91, 92, 93, 94, and 95 according to the program recorded in the ROM according to the flowchart of FIG.

  When a sheet jam occurs, the control unit 99 first determines whether the single-side mode or the double-side mode is selected (S11).

  In the case of the single-sided mode (YES in S11), the control unit 99 controls to normally discharge all the sheets downstream from the place where the sheet jam has occurred (S12). Next, a sheet clogging process is performed (S13). That is, the control unit 99 causes the operation panel 98 to display a message prompting the removal of the sheet staying in the image forming apparatus 100. Next, image formation is performed for the portion of the sheet that is upstream of the location where the sheet jam occurred and has been removed by the sheet jam processing (S13).

  In the case of the duplex mode (NO in S11), first, the control unit 99 determines whether or not there is a sheet in the reverse conveyance path 2 (S15). If there is a sheet in the reverse conveyance path 2, the sheet is conveyed to the retreat conveyance path 1 as it is and retreated (S16). Further, the sheet on which the image formation is completed at the downstream side of the place where the sheet is jammed is discharged out of the apparatus (S17). Next, a sheet clogging process is performed (S18). That is, the control unit 99 causes the operation panel 98 to display a message that prompts the user to remove a sheet (a sheet other than the retreat conveyance path 1) that has accumulated in the image forming apparatus 100. At the time of restart, image formation is performed for the removed sheet (S19), and image formation (second side) of the sheet that has been retracted to the retreat conveyance path 1 is performed.

  When the duplex mode is selected (NO in S11) and there is no sheet in the reverse conveyance path 2 (NO in S15), the paper on which image formation on both sides has been completed is discharged out of the apparatus (S21). . Then, the sheet on which the image is formed only on one side is conveyed to the retreat conveyance path 1 and retreated. Thereafter, the process proceeds to S18.

  According to this embodiment, the evacuation conveyance path 1 is arranged on the extension line of the reverse conveyance path 2. This eliminates the need for a guide member such as a dedicated flapper that switches the conveyance path for retraction. Therefore, the retreat conveyance path can be provided with a simple configuration.

  Further, since one sheet that can be used is retracted when a sheet jam occurs, the image of the sheet that has been removed by the sheet jam processing at the time of restart is formed first. Then, the page order can be restored to the original by transporting the retreated sheet to the retreat conveyance path 1. Further, the retreat conveyance path 1 of the present embodiment is connected to a conveyance path that leads to the upstream side of the image forming unit 13. Accordingly, when the sheet retracted on the retracting conveyance path 1 needs to be reversed, the sheet is conveyed to the reversing conveyance path 2 side. On the other hand, when the sheet retracted to the retracting conveyance path 1 does not need to be reversed, the sheet can be conveyed without being reversed by being conveyed to the image forming unit 13. Therefore, simple sheet conveyance control can be performed.

  In the above embodiment, the image forming apparatus that forms an image by the electrophotographic method is exemplified as the image forming unit. However, the image forming unit may be an apparatus that forms an image by, for example, an inkjet method.

DESCRIPTION OF SYMBOLS 1 Retraction conveyance path 2 Reverse conveyance path 13 Image formation part

Claims (9)

An image forming unit for forming an image on a sheet;
After the image is formed by the image forming unit, the sheet conveyed in the first direction is guided, and the sheet guided in the first direction is reversed and conveyed in the second direction opposite to the first direction. A reversing conveyance path that guides when
An image forming apparatus comprising: a retreat conveyance path that is connected to the reversal conveyance path and that receives a sheet sent from the reversal conveyance path in the first direction when an abnormality occurs.   The one end of the retreat conveyance path is connected to the reverse conveyance path, and the other end of the retraction conveyance path is connected to a conveyance path for conveying the sheet to the image forming unit. The image forming apparatus according to 1.   3. The sheet having image formation completed when an abnormality occurs is conveyed to the retreat conveyance path via the reverse conveyance path in response to the occurrence of the abnormality. The image forming apparatus described in 1.   4. The display according to any one of claims 1 to 3, wherein a display prompting removal of a sheet other than the sheet retracted to the retracting conveyance path is performed in a state where the sheet is retracted to the retracting transport path. The image forming apparatus described.   5. The image forming apparatus according to claim 4, wherein an image is formed on another sheet in a state where the sheet is retracted in the retracting conveyance path after the process of removing the sheet is completed.   The image forming apparatus according to claim 5, wherein the other sheet is reversely conveyed by the reversal conveyance path in a state where the sheet is retreated to the retreat conveyance path.   The sheet that has been retreated to the retreat conveyance path is conveyed outside the apparatus via the reversal conveyance path after conveying the other sheet on which image formation has been completed to the outside of the apparatus. Item 7. The image forming apparatus according to Item 5 or 6.   8. The image forming apparatus according to claim 5, wherein the image is formed on a sheet that has been retreated to the retreat conveyance path following image formation of the other sheet. 9. 9. The image forming apparatus according to claim 1, further comprising a re-conveying path that guides the sheet reversely conveyed from the reverse conveying path toward the image forming unit.

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