JP2005091739A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus in which the removal of a jam of paper is facilitated by simple structure. <P>SOLUTION: When a jam of paper occurs on a transport path and the paper is located upstream of a photoreceptor drum 31 being an image carrier, in the direction of the transport of the paper, namely, when only a resist sensor 23 in the vicinity of a pair of resist rollers 21 detects the jam, the pair of resist rollers 21 are reversely rotated to return the paper to the resist part 20. When the paper is located downstream of the photoreceptor drum 31 in the direction of the transport, namely, when only a post-transfer transport path sensor 39 disposed on a transport path B which is a post-transfer transport path, detects the jam, the paper is transported to an ejection side by a pair of transport rollers 36 disposed on the transport path B. When both of the post-transfer transport path sensor 39 and the resist sensor 23 detect jams, paper located upstream is returned to the resist part 20 by reversely rotating the pair of resist rollers 21 whereas paper located downstream is transported to the ejection side by the pair of transport rollers 36. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

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

  2. Description of the Related Art Conventionally, an image forming apparatus such as a copying machine or a printer that transfers a visible image formed on an image carrier made of a photosensitive drum or the like to a sheet for recording is known. In such an image forming apparatus, for example, in the case of a copying machine, when a paper jam occurs during the copying operation, the copying operation is stopped, and if the user does not remove all the paper on the conveyance path, the copying operation is performed. It cannot be restored. In this case, there is also a case in which the area where the paper is jammed is detected and illustrated on the screen.

In addition, even when the user forgets to remove the transfer paper at a position where there is no detection sensor at the time of jam processing, a configuration is disclosed in which the transfer paper is sent to the position where the detection sensor exists to detect forgetting jam processing. (For example, refer to Patent Document 1). In addition, a configuration is disclosed in which uncopied paper stopped near the registration portion can be reused when the copying operation is stopped due to a paper jam or the like (see, for example, Patent Document 2). In addition, a configuration is disclosed in which deterioration of the jammed state can be prevented and the removal and operability of the jammed paper can be improved to prevent an operator's erroneous operation (see, for example, Patent Document 3).
JP-A-9-90824 JP-A-11-249506 JP 2002-189398 A

  However, in the conventional configuration as described above, when a paper jam occurs during continuous feeding, a plurality of sheets are stopped on the conveyance path. In particular, in a high-speed copying machine or the like, once a paper jam occurs, a considerable number of sheets remain on the conveyance path. In such a case, for example, various process units such as a charging unit, a developing unit, and a transfer unit must be pulled out from the main body of the apparatus to clear the paper jam, and work must be performed. is there.

  In addition, since the number of sheets stopped inside the apparatus is unknown, there may occur a problem that the user tries to start the return operation such as closing the cover again, but the sheets are not completely removed, and the process is started again. . Even when the paper stop position is displayed, the exact position is not known, and the stopped paper may not be detected.

  SUMMARY An advantage of some aspects of the invention is that it provides an image forming apparatus that can easily clear a paper jam with a simple configuration.

  In order to achieve the above object, according to the present invention, in an image forming apparatus that performs recording by transferring an image formed on an image carrier onto a sheet, when a paper jam occurs on the sheet conveyance path, The sheet on the upstream side in the transport direction from the image carrier is returned to the registration side, and the paper on the downstream side in the transport direction from the image carrier is sent to the discharge side. To do.

  A first sensor for detecting the paper on the upstream side of the image carrier; and a second sensor for detecting the paper on the downstream side of the image carrier. When detected, the registration roller is rotated backward to return the upstream sheet to the registration side. When the second sensor detects, the conveyance roller is rotated forward to move the downstream sheet to the discharge side. It is characterized by being sent out.

  Further, when both the first sensor and the second sensor detect, the registration roller is rotated in the reverse direction to return the upstream sheet to the registration side, and the conveyance roller is rotated in the forward direction to move the downstream side. The paper is sent out to the discharge side.

  In addition, the number of sheets on the discharge side and the sheet on the registration side, or the number of sheets on the downstream side and the upstream side as viewed from the image carrier are displayed.

  According to the present invention, it is possible to provide an image forming apparatus capable of easily clearing a paper jam with a simple configuration. Specifically, it becomes possible to perform paper jam processing by distinguishing between the transferred paper and the non-transferred paper. Further, the user can determine the number of sheets that can be recycled and the number of sheets that cannot be recycled.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. The image forming apparatus according to the present invention includes a detection unit that detects a sheet on the conveyance path and a control unit that controls a copying operation of the main body. When a paper jam occurs on the conveyance path, the control unit stops the copying operation and obtains the position of the sheet stopped on the conveyance path by the detection unit. At this time, if the paper position is upstream from the image carrier in the conveying direction, that is, if only the registration sensor in the vicinity of the registration roller is detecting, the registration roller is rotated in the reverse direction to move the paper to the registration section. return.

  In addition, when the paper position is on the downstream side of the conveyance direction with respect to the image carrier, that is, when only the post-transfer conveyance path sensor provided in the post-transfer conveyance path detects, the conveyance provided in the post-transfer conveyance path The paper is sent to the discharge side by the roller. In addition, when both the post-transfer conveyance path sensor and the registration sensor detect, the upstream side paper rotates the registration roller in the reverse direction to return to the registration unit, and the downstream side paper is sent to the discharge side by the conveyance roller. It is configured.

  FIG. 1 is a longitudinal sectional view of an image forming apparatus according to Embodiment 1 of the present invention, showing an example of a copying machine. As shown in the figure, a document placing glass 3 and a document cover 2 for opening and closing the document placing glass 3 are provided on the upper part of the main body 1. An image information reading unit 10 that reads image information of a document (not shown) placed on the document placement glass 3 is disposed below the document placement glass 3. The image information reading unit 10 includes a light source 11, movable mirrors 12 to 14, a fixed lens 15, and fixed mirrors 16 to 18.

  The light source 11 and the movable mirrors 12 to 14 are disposed so as to be able to reciprocate below the document placement glass 3, and the light source 11 irradiates the document on the document placement glass 3. The reflected light reaches the exposure unit 33 on the photosensitive drum 31 in the image carrier 30 described later via an optical system including the movable mirrors 12 to 14, the fixed lens 15, and the fixed mirrors 16 to 18. In the main body 1, an image carrier 30 and a fixing unit 40 are provided below the image information reading unit 10, and a registration unit 20 and a paper feed unit 50 are provided below the image carrier 30.

  The image carrier 30 is provided with a photosensitive drum 31 as an image carrier. The photosensitive drum 31 is uniformly charged by a charging unit 32, and the exposure unit 33 receives image information from the original. Is applied to the peripheral surface of the photosensitive drum 31 to form an electrostatic latent image. The electrostatic latent image is developed by the developing unit 34 to form a toner image. Then, in synchronization with the rotation of the photosensitive drum 31, the paper is sent to the transfer unit 35 to transfer the toner image. Thereafter, the sheet is separated from the photosensitive drum 31 and conveyed to the fixing unit 40 in the next process by the conveyance roller pair 36 provided in the conveyance path B which is a conveyance path after transfer. A post-transfer conveyance path sensor 39 as a sheet detection unit is provided in the vicinity of the conveyance roller pair 36. As the post-transfer conveyance path sensor 39, for example, a reflective photo interrupter or the like is used.

  A cleaning unit 37 is disposed around the photosensitive drum 31 to clean the surface of the photosensitive drum 31 after transfer. Subsequently, the charge is removed by the charge removing unit 38 and then charged again by the charging unit 32 for the next image formation. On the other hand, the fixing unit 40 includes a pair of fixing rollers 41 and 42, and thereby heats and pressurizes the sheet to fix the toner image. After fixing, the pair of paper discharge rollers 43 and 44 discharge the paper to the discharge unit 45.

  The paper feed section 50 is provided with a plurality of paper feed stage sections 51a, 51b, and 51c, which are arranged in the upper, middle, and lower stages, respectively, in this embodiment. In addition, trays 52a, 52b, and 52c for storing paper are disposed in the paper feed stages 51a, 51b, and 51c, respectively. Paper feed rollers 53a, 53b, and 53c are disposed on the upper surfaces of the papers of the paper feed stages 51a, 51b, and 51c, respectively, and feed the paper intermittently. In front of each of the paper feed rollers 53a, 53b, and 53c, a pair of double feed prevention rollers 54a, 54b, and 54c are provided, respectively, to transport the sheets one by one to the transport path A. In the conveyance path A, conveyance roller pairs 55a, 55b, and 55c that constitute conveyance means are disposed.

  A registration roller pair 21 and a feed roller pair 22 are disposed in the registration unit 20 to which the sheet from the conveyance path A is conveyed. A registration sensor 23 serving as a sheet detection unit is provided in the vicinity of the registration roller pair 21. Is provided. As the resist sensor 23, for example, a reflective photo interrupter or the like is used. The registration roller pair 21 and the feed roller pair 22 are driven independently. The conveyed paper abuts against the registration roller pair 21, aligns the image on the image carrier with the paper, and forcibly forms a spool to correct the skew of the paper, and cancels this spool. In this way, the image is supplied to the image carrier 30.

  In this embodiment, as described above, the registration sensor 23 and the post-transfer conveyance path sensor 39, which are detection means for detecting the paper on the conveyance path, and the control means (not shown) for controlling the copying operation of the main body are provided. When a paper jam occurs on the conveyance path, the control unit stops the copying operation and obtains the position of the sheet stopped on the conveyance path by the detection unit. At this time, if the paper position is upstream of the photosensitive drum 31 as the image carrier with respect to the transport direction, that is, if only the registration sensor 23 in the vicinity of the registration roller pair 21 is detecting, the registration roller pair 21 is reversely rotated to return the paper to the registration unit 20.

  If the paper position is downstream of the photosensitive drum 31 with respect to the conveyance direction, that is, if only the post-transfer conveyance path sensor 39 provided in the conveyance path B which is the post-transfer conveyance path is detected, the conveyance is performed. The sheet is sent out to the discharge side by a pair of conveying rollers 36 provided in the path B. Further, when both the post-transfer conveyance path sensor 39 and the registration sensor 23 detect, the upstream sheet reversely rotates the registration roller pair 21 and returns to the registration unit 20, and the downstream sheet is the conveyance roller. The pair 36 is configured to send out to the discharge side.

  FIG. 2 is a flowchart showing the control content of the copying operation in this embodiment. In the figure, when copying starts, first, in step S5, it is determined whether or not there is a paper jam. If there is a paper jam, the process proceeds to step S10 to stop the copying operation. Subsequently, the process proceeds to step S15 to determine whether or not the registration sensor 23 has detected. If the registration sensor 23 has not detected, the process proceeds to step S20, and it is determined whether or not the post-transfer conveyance path sensor 39 has detected. If the post-transfer conveyance path sensor 39 has not detected, the process proceeds to step S25, and the number of sheets stopped on the conveyance path is obtained from the timing of paper jam, the number of fed sheets, the number of discharged sheets, etc. Display on the display panel of the operation unit. Subsequently, the process proceeds to step S30, where the user removes the sheet on the conveyance path and returns to step S5.

  In step S5, if there is no paper jam, the process proceeds to step S35, where the normal operation is performed and the process ends. In step S15, if the registration sensor 23 has detected, the process proceeds to step S40, and it is determined whether or not the post-transfer conveyance path sensor 39 has detected. If the post-transfer conveyance path sensor 39 has not detected, the process proceeds to step S45, and the registration roller pair 21 is reversely rotated to perform reverse registration roller feeding. Subsequently, the process proceeds to step S25.

  If the post-transfer conveyance path sensor 39 detects in step S40, the process proceeds to step S50, the registration roller pair 21 is reversely rotated to perform the registration roller reverse feed, and then the process proceeds to step S55. The pair 36 is rotated forward to carry forward the conveyance rollers. Then, the process proceeds to step 25. If the post-transfer conveyance path sensor 39 detects in step S20, the process proceeds to step S60, and the conveyance roller pair 36 is rotated forward to carry the conveyance rollers forward. Subsequently, the process proceeds to step S25.

  By performing the copying operation with the control contents as described above, it becomes possible to distinguish between the transferred paper and the non-transferred paper and perform the paper jam processing. Further, when displaying the number of stopped sheets in step S25, the transferred paper and the untransferred paper, in other words, the discharge side paper and the registration side paper, or the downstream side paper and the upstream side when viewed from the image carrier. By distinguishing and displaying the side sheets, the user can determine the number of sheets that can be regenerated and the number of sheets that cannot be regenerated.

  The first sensor referred to in the claims corresponds to the registration sensor in the embodiment, and the second sensor corresponds to the post-transfer conveyance path sensor.

  The present invention has been described with reference to a copying machine as an embodiment. However, the present invention is not limited to this, and any printer or facsimile can be used as long as a sheet conveyance path is provided before and after the image carrier. It is also applicable to the device.

1 is a longitudinal sectional view of an image forming apparatus according to Embodiment 1 of the present invention. 6 is a flowchart showing control details of a copying operation in the present embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Main body 2 Original cover 3 Original document glass 10 Image information reading part 11 Light source 12-14 Movable mirror 15 Fixed lens 16-18 Fixed mirror 20 Registration part 21 Registration roller pair 22 Feed roller pair 23 Registration sensor 30 Image carrying part 31 Photosensitive Body drum 32 Charging unit 33 Exposure unit 34 Development unit 35 Transfer unit 36 Conveying roller pair 37 Cleaning unit 38 Static eliminating unit 39 Post-transfer conveyance path sensor 40 Fixing unit 41, 42 Fixing roller 43, 44 Paper discharge roller 45 Ejecting unit 50 Paper feeding Sections 51a, 51b, 51c Paper feed stage sections 52a, 52b, 52c Tray 53a, 53b, 53c Paper feed rollers 54a, 54b, 54c Double feed prevention roller pair 55a, 55b, 55c Transport roller pair A, B Transport path

Claims (4)

  In an image forming apparatus that performs recording by transferring an image formed on an image carrier onto a sheet, when a paper jam occurs on the sheet conveyance path, the image carrier is upstream of the conveyance direction. An image forming apparatus, wherein the sheet is returned to the registration side, and the sheet located downstream of the image carrier in the transport direction is sent to the discharge side.   A first sensor for detecting the paper on the upstream side of the image carrier, and a second sensor for detecting the paper on the downstream side of the image carrier, the first sensor detecting Sometimes, the registration roller is reversely rotated to return the upstream sheet to the registration side, and when the second sensor detects, the transport roller is rotated forward to send the downstream sheet to the discharge side. The image forming apparatus according to claim 1, wherein:   When both the first sensor and the second sensor detect, the registration roller is reversely rotated to return the upstream sheet to the registration side, and the conveyance roller is rotated forward to rotate the downstream sheet. The image forming apparatus according to claim 2, wherein the image forming apparatus is configured to send the ink to the discharge side.   4. The number of sheets on the discharge side and the number of sheets on the registration side, or the number of sheets on the downstream side and the upstream side as viewed from the image carrier, respectively, are displayed. The image forming apparatus according to any one of the above.

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