JP5489596B2 - Image forming apparatus - Google Patents

Description

  The present invention relates to an image forming apparatus, and more particularly to an image forming apparatus provided with a retraction tray (escape tray) for discharging a multi-feed sheet.

  Conventionally, in an image forming apparatus such as a copying machine or a printer, sheets may be fed in an overlapping manner. When such a sheet feeding occurs, the sheet stops (stays) in the middle of the conveyance path. Or jammed by being delayed (delayed) by a predetermined transport time. When a sheet feeding failure (jam) during conveyance occurs in this way, a message is displayed on the display unit provided in the operation unit or the like to stop the sheet conveyance and remove the jammed sheet. Like to do.

  Note that even when sheets are double-fed, the double-fed sheets may not be jammed in the conveyance path, and may be discharged to the tray after completion of image formation. In this case, the conveyance of the sheet does not stop, but blank sheets, that is, sheets without images are mixed in the image-formed product, and when sheets of blank pages are mixed in this way, when binding sheets It becomes a problem in etc. Therefore, conventionally, for example, a retreat tray (escape tray) for discharging the multi-fed sheets is connected to a sheet processing apparatus that is connected to an image forming apparatus and performs processing such as stapling by bundling sheets with image formation. The provided one has been proposed (see Patent Document 1).

  In recent years, in the field of application of electrophotographic image forming apparatuses, the base has been expanded from personal use to professional use. As such an application field, there is a print-on-demand (POD) capable of light printing, for example, a variety of products and a small amount of printing. In such an image forming apparatus used in the field of POD, a sheet feeding unit having a plurality of sheet storage portions such as a sheet feeding cassette is provided on the side of the image forming apparatus main body so that a large number of types of sheets can be supplied. There are several in parallel. In the image forming apparatus (image forming system) having such a configuration, it is necessary to prevent the apparatus from being stopped as much as possible even when sheets from these sheet feeding units are double-fed. In view of this, there has been proposed one in which a retraction tray is provided in a paper supply unit arranged at the most downstream of the plurality of paper supply units, and the sheets fed to the retraction tray are discharged (Patent Document 2). reference).

JP 2007-62956 A JP 2007-279168 A

  By the way, in such a conventional image forming apparatus, when the sheet fed from the sheet feeding cassette of the image forming apparatus main body is being double-fed, the double-fed sheet is discharged through the image forming unit, or already. The sheet is discharged to a retract tray provided in the sheet processing apparatus described above. Here, in general, a sheet that is being multi-fed is likely to cause a jam. Therefore, if the multi-fed sheet is discharged in this way, a jam may occur when the sheet passes through the image forming unit. For this measure, if the image forming apparatus main body is provided with a retract tray for discharging the multi-feed sheets as in the case of the paper feeding unit, the image forming apparatus main body cannot be increased in size and the cost is reduced. It also hinders conversion. Further, if the evacuation tray exists in both the paper feeding unit and the image forming apparatus main body, the user needs to collect the multi-feed sheets from the two evacuation trays, and the work efficiency is lowered.

  Accordingly, the present invention has been made in view of such a current situation, and an image forming apparatus capable of discharging a multi-feed sheet without increasing the size of the image forming apparatus main body and without causing a jam. Is intended to provide.

The present invention provides an image forming unit having an image forming unit that forms an image on a sheet, and a main body sheet feeding unit that feeds the sheet to the image forming unit, and the image forming unit connected to the main body of the image forming device. A sheet feeding unit having a unit sheet feeding unit and a sheet feeding unit having a retraction tray from which a sheet in which double feeding is detected is discharged, provided in the image forming apparatus main body, A main body sheet conveyance path that guides the sheet fed from the main body sheet feeding unit to the image forming unit, and a sheet that is provided in the sheet feeding unit and that is fed from the unit sheet feeding unit. A unit-side sheet conveyance path that guides the forming unit; a first conveyance path that is provided in the image forming apparatus main body and branches from the main body sheet conveyance path; and a sheet feeding unit. A second conveyance path that guides the sheet that has passed through the first conveyance path toward the unit-side sheet conveyance path, and a branch from the unit-side sheet conveyance path, the main body sheet feeding unit and the unit sheet feeding A retraction conveyance path that guides the sheet fed from the feeding section toward the retraction tray, and a branch point of the unit side sheet conveyance path where the retraction conveyance path branches; A switching member that switches the feeding direction of the sheet fed from the unit sheet feeding unit from the unit-side sheet conveyance path to the retreat conveyance path; and the second conveyance path of the switching member and the unit-side sheet conveyance path And a unit for detecting the double feeding of the sheet fed from the main body sheet feeding unit, and the unit sheet by the double feeding detection unit. A control unit that switches the switching member so that the double fed sheet is directed to the retreat conveyance path when double feeding of the sheet fed from the feeding unit is detected. To do.

  As in the present invention, the size of the main body of the image forming apparatus can be increased by discharging the multi-feed sheet from the sheet feeding unit on the apparatus main body side to a retraction tray provided in the sheet feeding unit. And it can be discharged without causing jamming.

1 is a diagram illustrating a schematic configuration of a printer that is an example of an image forming apparatus according to a first embodiment of the present invention. FIG. 3 is a control block diagram of the printer. FIG. 4 is a diagram illustrating a multifeed sheet removal control operation of the printer. FIG. 4 is a diagram illustrating a schematic configuration of a printer (image forming apparatus) according to a second embodiment of the invention. FIG. 9 is a diagram illustrating a schematic configuration of a printer (image forming apparatus) according to a third embodiment of the invention.

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments for carrying out the present invention will be described in detail with reference to the drawings. FIG. 1 is a diagram illustrating a schematic configuration of a printer as an example of an image forming apparatus according to a first embodiment of the present invention. In FIG. 1, reference numeral 1 denotes a printer. The printer 1 includes a printer main body 2 that is an image forming apparatus main body, and a scanner 3 that is disposed on the upper surface of the printer main body 2 and reads a document. When reading a document, the scanner 3 irradiates a document (not shown) placed on the platen glass 120 with light by a scanning optical system light source and reads a document image by inputting reflected light to the CCD. I am doing so. Then, the read original image is converted into an electric signal and transmitted to the laser scanner 100 as image forming means. Note that image data transmitted from a personal computer or the like may be input to the laser scanner 100.

  The printer main body 2 includes an image forming unit 4, a sheet feeding device 5 that feeds the sheet P, and a sheet conveying device 6 that conveys the sheet P fed by the sheet feeding device 5 to the image forming unit 4. ing. Here, the sheet feeding device 5 that is a main body sheet feeding unit on the image forming apparatus main body side includes a sheet storage unit 5 a that can be pulled out to the printer main body 2, a pickup roller 5 b, and a retard roller pair 146. ing. The sheets P in the sheet storage portion 5a are separated and fed one by one by the action of the pickup roller 5b that moves up and down / rotates at a predetermined timing and the retard roller pair 146. A double feed detection unit 160 that detects double feed of the sheet P is provided near the downstream side of the retard roller pair 146 in the sheet conveyance direction.

  The sheet conveying device 6 includes vertical path rollers 147 a and 147 b provided in the vertical path 155 and a registration roller pair 148. Then, the sheet P fed from the sheet feeding device 5 is once abutted against the stopped registration roller pair 148 by the vertical path rollers 147a and 147b. Here, once the sheet P is abutted against the resist roller pair 148 that has stopped, the sheet P forms a predetermined loop at the front part of the registration roller pair, and then becomes parallel to the drum axis due to rigidity. It is corrected. Thereafter, the registration roller pair 148 is driven at a predetermined timing, whereby the sheet P is conveyed to the image forming unit 4. The image forming unit 4 includes a photosensitive drum 102, a laser scanner 100, a developing unit 103, a transfer charger 104 that forms a transfer unit, a primary charger 107, and the like.

  At the time of image formation, the latent image is formed on the photosensitive drum by irradiating the photosensitive drum 102 with the laser beam L from the laser scanner 100. Further, the latent image formed on the photosensitive drum in this way is thereafter visualized as a toner image by the developing unit 103. Thereafter, the toner image on the photosensitive drum is transferred to the sheet P by the transfer charger 104 in the transfer portion. The residual toner on the drum is collected by the cleaner 106 and used for the next image formation. Further, the sheet P onto which the toner image has been transferred in this manner is conveyed to the fixing device 150 by the conveying belt 105 to fix the toner image, and thereafter, the toner image is fixed to the discharge tray 153 by the conveying roller 151 and the discharge roller 152. Discharged.

  The printer 1 includes an operation panel shown in FIG. 2 described later having a display unit for confirming necessary information such as setting of various modes and operating states, and the display unit has an abnormality such as sheet feeding failure. The contents of work are displayed to the user. The printer 1 also includes a control unit shown in FIG. 2, which will be described later, for controlling the operation of the laser scanner 100, the image forming unit 4 and the like with a predetermined program according to the set operation mode. Further, a sheet processing apparatus (not shown) is connected to the printer main body 2 when processing such as bookbinding. When performing processing such as bookbinding, the sheet after image formation is loaded. It is conveyed to the sheet processing apparatus.

  Furthermore, in the present embodiment, a large-capacity paper deck 7 that is a sheet feeding unit capable of storing a large amount of sheets as an option is detachably connected to the printer body 2. Then, by connecting such a paper deck 7 to the printer main body 2, a large amount of images can be continuously formed. The paper deck 7 also includes a sheet feeding device 5 </ b> A that includes a sheet storage unit 5 a, a pickup roller 5 b, and a retard roller pair 181 and conveys the sheet P to the image forming unit 4. When the sheet P is fed from the paper deck 7, the sheet P is first fed from the sheet storage portion 5a by the pickup roller 5b, and the sheet P is separated one by one by the action of the retard roller pair 181. Next, the sheet P thus separated one by one is transferred to the conveyance roller 149 in the printer main body by the conveyance roller pairs 182a to 182f. After that, the sheet P transferred to the conveying roller 149 forms an image by the same processing as the sheet P fed from the sheet feeding device 5 of the printer main body 2 described above.

  By the way, the paper deck 7 includes a multi-feed detection unit 190 that detects a multi-feed of sheets fed from the sheet feeding device 5A that is a unit sheet feeding unit on the sheet feeding unit side, and a multi-feed sheet. An escape tray 188 is provided as a retraction tray for discharging the waste. In the present embodiment, the double feed detection unit 160 on the printer main body side and the double feed detection unit 190 on the paper deck side are configured to detect double feed, for example, by detecting a change in sheet thickness. In addition, the paper deck 7 includes a sheet conveyance path 180 that is a unit-side sheet conveyance path for conveying the sheet fed from the sheet feeding device 5 </ b> A to the printer main body 2. Further, the paper deck 7 includes a first escape path 183 that is branched from the sheet conveyance path 180 and conveys the multi-feed sheet to the escape tray 188. In FIG. 1, reference numeral 184 denotes a unit-side switching member provided at a branch point between the sheet conveyance path 180 and the first escape path 183. When the double feed detection unit 190 detects the double feed of the sheet fed from the sheet feeding device 5A, the control unit 200 shown in FIG. 2 to be described later is based on a signal from the double feed detection unit 190. The switching member 184 is switched to guide the sheet to the first escape path 183. Further, the paper deck 7 includes a second escape path 193 that is a retreat conveyance path for conveying the multi-feed sheet conveyed from the sheet feeding unit 5 on the printer main body side to the escape tray 188 as will be described later.

  On the other hand, the printer main body 2 includes the above-described vertical path 155 that is a sheet conveyance path of the printer main body 2 that guides the sheet from the sheet feeding device 5 toward the image forming unit 4. Further, the printer main body 2 branches from a vertical path 155 that is a main body sheet conveyance path, and the main body side escape path that guides the sheets fed from the sheet feeding device 5 toward the second escape path 193 of the paper deck 7. 143. The sheet fed from the sheet feeding unit 5 on the printer body side is fed by the body side escape path 143 that is the first transport path and the second escape path 193 of the paper deck 7 that is the second transport path. A retreat conveyance path ER is formed in the escape tray 188. In FIG. 1, reference numeral 144 denotes a printer main body side (apparatus main body side) switching member provided at a branch point between the vertical path 155 and the main body side escape path 143. When the double feed detection unit 160 detects the double feed of the sheet, the control unit 200 shown in FIG. 2 to be described later switches the switching member 144 on the printer main body side based on a signal from the double feed detection unit 160. The sheet is guided to the main body side escape path 143.

  FIG. 2 is a control block diagram of the printer 1. The control unit 200 includes an operation including a double feed detection unit 160 on the printer body side, a double feed detection unit 190 on the paper deck side, a switching member 184 on the paper deck side, a switching member 144 on the printer body side, and a display unit (not shown). Unit 201 is connected. Then, as described above, the control unit 200 switches the switching member 144 based on the signal from the double feed detection unit 160 on the printer body side, and switches based on the signal from the double feed detection unit 190 on the paper deck side. 184 is switched. In the present embodiment, the control unit 200 is provided in the printer main body 2, but the switching members 144 and 184 are supplied to the printer main body 2 and the paper deck 7 based on signals from the double feed detection units 160 and 190, respectively. A control unit for switching between the two may be provided.

  Next, the double feed sheet removal control operation of the printer 1 configured as described above will be described. For example, when the double feed detection unit 160 detects double feed of sheets fed from the sheet feeding device 5 on the printer main body side, the control unit 200 switches the switching member 144 based on a signal from the double feed detection unit 160. The vertical path 155 is blocked and the sheet is guided to the main body side escape path 143. As a result, as shown in FIG. 3A, the multi-feed sheet PW is transported by the transport roller pair 145 in the main body side escape path in the printer main body and heads toward the second escape path 193 in the paper deck. Thereafter, the multi-feed sheet P merges with the first escape path 183 by the conveyance roller pairs 185 a and 185 b in the second escape path 193, and is conveyed to the escape tray 188 by the conveyance roller pairs 186 and 187. Further, when the double feed detection unit 190 detects the double feed of the sheet fed from the sheet feeding device 5 </ b> A of the paper deck 7, the control unit switches the switching member 184 based on a signal from the double feed detection unit 190. As a result, the switching member 184 blocks the sheet conveyance path 180 connected to the image forming unit 4 (transfer unit), and as shown in FIG. Go to 1 escape path 183. Thereafter, the double feed sheet PW is discharged to the escape tray 188 by the pair of conveying rollers 186 and 187 in the first escape path 183.

  When the multi-feed sheet PW from the sheet feeding device 5 on the printer main body side or from the paper deck 7 is forcibly discharged to the escape tray 188 in this way, it should be transferred to the discharged sheet. The toner image on the photosensitive drum is collected by the cleaner 106. That is, when the double feeding of the sheet is detected, the toner image on the photosensitive drum is collected by the cleaner 106 without performing normal transfer control. Further, after detecting double feeding, the same toner image is formed on the photosensitive drum, and a new sheet is conveyed to the transfer unit, whereby an image is formed on a sheet instead of the removed sheet. By performing such control, the user can operate the image forming apparatus without processing the multi-feed sheet even when the multi-feed sheet is generated.

  As described above, in this embodiment, when a multi-feed sheet is detected by the printer body 2, the multi-feed sheet is discharged to the escape tray 188 of the paper deck 7. That is, when a sheet is double-fed from the sheet feeding device 5 on the printer main body side, the double-fed sheet is discharged to an escape tray 188 provided on the paper deck 7. Thus, the multi-feed sheet can be discharged without providing an escape tray in the printer body, that is, without increasing the size of the printer body 2 and without causing a jam. Also, with this configuration, it is possible to automatically remove the multi-feed sheet, so that it is possible to reduce the jam processing time by the user in the transport path and eliminate the mixing of blank pages due to multi-feed. Furthermore, since double feed sheets from both the image forming apparatus and the sheet feeding apparatus can be collected by one escape tray, the collection workability is improved and the cost is reduced.

  Next, a second embodiment of the present invention will be described. FIG. 4 is a diagram showing a schematic configuration of a printer (image forming apparatus) according to the present embodiment. In FIG. 4, the same reference numerals as those in FIG. 1 described above indicate the same or corresponding parts. In FIG. 4, reference numeral 188 </ b> A denotes an escape tray, and this escape tray 188 </ b> A is provided in a position near the printer main body 2 inside the paper deck. When the double feed detection unit 160 detects double feed of the sheet P fed from the sheet feeding device 5 of the printer main body 2, the control unit 200 switches the switching member 144, thereby overlapping the escape path 143 on the main body side. The feeding sheet is headed. Thereafter, the multi-feed sheet is conveyed by the conveying roller pair 145 in the main body side escape path and travels toward the second escape path 193 in the paper deck. Thereafter, the multi-feed sheet P is conveyed to the first escape path 183 by the conveyance roller pair 185 in the second escape path 193 and is conveyed to the escape tray 188A by the conveyance roller pair 187. When the double feed detection unit 190 detects double feed of the sheets fed from the sheet feeding device 5A of the paper deck 7, the control unit 200 switches the switching member 184 based on a signal from the double feed detection unit 190. . As a result, the switching member 184 blocks the sheet conveyance path 180, and the multi-feed sheet P moves toward the first escape path 183. Thereafter, the multi-feed sheet P is discharged to the escape tray 188A by the conveying roller pair 186 and 187 in the first escape path 183. Here, in the present embodiment, by providing the escape tray 188A inside the paper deck, in particular, the length of the second escape path 193 in the paper deck can be shortened, resulting in space saving and cost reduction. It becomes possible.

  By the way, in the first and second embodiments described so far, the double feed detectors 160 and 190 are provided in the printer main body 2 and the paper deck 7, but the double feed detector 190 is provided only in the paper deck 7. Anyway. Next, a third embodiment of the present invention in which a double feed detector is provided only on the paper deck 7 will be described. FIG. 5 is a diagram showing a schematic configuration of a printer (image forming apparatus) according to the present embodiment. In FIG. 5, the same reference numerals as those in FIG. 1 described above indicate the same or corresponding parts. In FIG. 5, 193 </ b> A is provided on the paper deck 7, and conveys a multi-feed sheet conveyed from the sheet feeding unit 5 on the printer main body side to the upstream side of the sheet conveyance path 180 in the sheet conveyance direction of the multi-feed detection unit 190. It is the 2nd escape path which is the 2nd conveyance way. In this embodiment, when the sheet is likely to cause double feeding, the switching member 144 is switched in advance so that the sheet P from the sheet feeding device 5 on the printer main body side is transferred from the main body side escape path 143 to the second escape. Guidance is made toward the path 193A. Here, the second escape path 193A merges with the sheet conveyance path 180, which is a unit-side sheet conveyance path, on the upstream side of the double feed detection unit 190. Accordingly, the sheet conveyance path for conveying the sheet P from the sheet feeding device 5 to the image forming unit 4 is the second escape path 193A of the main body side escape path 143, the second escape path 193A, and the sheet conveyance path 180. It is comprised by the downstream part rather than the confluence | merging point.

  With this configuration, in the case of a sheet that is easily fed, the sheet P fed from the sheet feeding device 5 on the printer main body side goes from the main body side escape path 143 to the second escape path 193A. Thereafter, the multifeed detection unit 190 provided between the switching member 184 and the junction where the second escape path 193A of the sheet conveyance path 180 is merged is conveyed from the second escape path 193A to the sheet conveyance path 180. pass. At this time, when double feed is detected by the double feed detection unit 190, the switching member 184 is switched based on a signal from the double feed detection unit 190, and the double feed sheet P moves toward the first escape path 183. Thereafter, the multi-feed sheet P is discharged to the escape tray 188A by the conveying roller pair 186 and 187 in the first escape path 183. As described above, by providing the multifeed detection unit 190 only on the paper deck 7 as in the present embodiment, the number of used multifeed detection units can be reduced, and the cost can be reduced. .

DESCRIPTION OF SYMBOLS 1 ... Printer, 2 ... Printer main body, 4 ... Image forming part, 5 ... Sheet feeding apparatus, 5A ... Sheet feeding apparatus, 7 ... Paper deck, 143 ... Main body side escape path, 144 ... Switching member, 155 ... Vertical path 160 ... multiple feed detection unit, 180 ... sheet conveyance path, 183 ... first escape path, 184 ... switching member, 188 ... escape tray, 188A ... escape tray, 190 ... multiple feed detection unit, 193 ... second escape path, 193A ... second escape path, 200 ... control unit, ER ... retreat conveyance path, P ... sheet

Claims (3)

An image forming apparatus main body having an image forming section for forming an image on a sheet and a main body sheet feeding section for feeding the sheet to the image forming section, and connected to the main body of the image forming apparatus and feeding the sheet to the image forming section In an image forming apparatus comprising: a unit sheet feeding unit that feeds and a sheet feeding unit that includes a retraction tray from which a sheet in which double feeding is detected is discharged;
A main body sheet conveyance path that is provided in the image forming apparatus main body and guides the sheet fed from the main body sheet feeding unit to the image forming unit;
A unit-side sheet conveyance path that is provided in the sheet feeding unit and guides the sheet fed from the unit sheet feeding unit to the image forming unit;
A first conveyance path provided in the image forming apparatus main body and branched from the main body sheet conveyance path;
A second conveyance path that is provided in the sheet feeding unit and guides the sheet that has passed through the first conveyance path toward the unit-side sheet conveyance path;
A retreat conveyance path that branches from the unit side sheet conveyance path and guides the sheet fed from the main body sheet feeding unit and the unit sheet feeding unit toward the retraction tray;
The unit-side sheet conveyance path is provided at a branch point of the unit-side sheet conveyance path where the evacuation conveyance path branches, and the feeding direction of the sheet fed from the main body sheet feeding unit and the unit sheet feeding unit A switching member for switching from the path to the retreat conveyance path;
A multi-feed detection unit that is provided between the switching member and a merging unit where the second conveyance path of the unit-side sheet conveyance path merges, and detects a multi-feed of the sheet fed from the main body sheet feeding unit. When,
Control for switching the switching member so that the double fed sheet is directed to the retreat conveyance path when the double feeding of the sheet fed from the unit sheet feeding unit is detected by the double feeding detecting unit. And an image forming apparatus. A switching member on the apparatus main body side provided at a branch point of the main body sheet conveyance path where the first conveyance path branches;
Wherein the control unit, the switching member of the image forming apparatus according to claim 1, wherein the switching the switching member so as to direct the sheet to the first conveying path in accordance with the type of sheet. 3. The image forming apparatus according to claim 1, wherein the evacuation tray is provided inside the sheet feeding unit at a position close to the main body of the image forming apparatus.

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