JP2006096502A - Image forming device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming device capable of continuously forming images even if abnormal feeding of sheets occurs, while restricting influence of the abnormal feeding of the sheets. <P>SOLUTION: This image forming device 1 is provided with a recording means for recording image data, an image forming means for forming the image data recorded by the recording means on a sheet, a sheet feeding means for feeding the sheet to the image forming means, while separating them one by one, and a sheet conveying means for conveying the sheet formed with the image by the image forming means. A sheet feeding passage, in which the sheets are fed by the sheet feeding means, is provided with an abnormal feeding detecting means 35 for detecting abnormal feeding of the sheet and a sheet discharging means 51 for discharging a sheet J, of which abnormal feeding is detected by the abnormal feeding detecting means 35, from the feeding passage. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an image forming apparatus that can detect abnormal feeding of a sheet on which an image is to be formed.

  A copying machine, a printer, or the like is used as an image forming apparatus that feeds a sheet fed from a stacking unit for stacking sheets to an image forming unit and forms an image on the sheet. Such an image forming apparatus detects a sheet by reversing the sheet and detecting a function of forming an image on both sides of the sheet, and double feeding (hereinafter referred to as double feeding) when the sheets are overlapped. Some have a function to warn the user of clogging. When the multi-feed is detected, the image forming apparatus prompts the user with a warning and stops the image forming operation to prevent further sheet jamming.

  On the other hand, in recent years, when printing publications, print-on-demand is often used in which digital data created by DTP or the like whose design and layout are performed on a personal computer is directly printed without going through the plate making process. An image forming apparatus for printing publications has been required to have high productivity and quality.

  However, the conventional image forming apparatus warns the user when the double feed is detected and stops the image forming operation. Therefore, the image forming operation cannot be performed until the user processes the sheet jamming. The decrease in productivity due to double feeding has been a problem. In particular, the printing of the publication has been a significant problem.

In recent years, an image forming apparatus has been proposed in which a conveyance interval of a sheet on which an image is formed is controlled to be short as the image forming speed is increased. Since the image forming apparatus conveys a large amount of sheets in a short time, a large amount of sheets are jammed due to a single jam. Further, the image forming apparatus is relatively likely to cause double feeding of sheets, and multi-feed sheets (sheets on which images are not formed) may be mixed in a printed publication, resulting in a reduction in product quality. was there.
JP-A-5-262443

  The present invention has been made in view of the above-mentioned various problems, and is less affected by abnormal sheet feeding, and can perform image forming operations continuously even when abnormal sheet feeding occurs. An object is to provide a forming apparatus.

  In order to solve the above problems, the present invention is configured as follows. The present invention provides a recording unit that records image data, an image forming unit that forms image data recorded in the recording unit on a sheet, and a sheet feeding unit that separates and feeds sheets one by one to the image forming unit. An image forming apparatus comprising: a feeding unit; and a sheet conveying unit configured to convey a sheet formed with an image by the image forming unit, wherein a sheet feeding path of the sheet fed by the sheet feeding unit includes a sheet Abnormality detecting means for detecting the abnormal feeding of the sheet, and sheet discharging means for discharging the sheet whose abnormal feeding has been detected by the abnormality detecting means from the feeding path.

  The image forming apparatus according to the present invention can discharge the sheet abnormally fed by the sheet discharge unit in the feeding path, and therefore, without abnormally feeding, the image forming operation is continuously stopped. Thus, an image forming operation can be performed. In addition, since a recording unit that records image data to be formed on a sheet is provided, it is possible to perform image formation again as necessary when abnormal feeding is performed, and continuous image formation can be performed. It becomes possible.

  The best mode for carrying out the present invention will be exemplarily described in detail below with reference to the drawings. However, the dimensions, materials, shapes, relative arrangements, and the like of the components described in this embodiment are not intended to limit the scope of the present invention only to those unless otherwise specified. The image forming apparatus according to the present invention is not limited to the one having the configuration described below.

  FIG. 1 is a schematic cross-sectional view of a copying machine 1 as an image forming apparatus according to the present embodiment. The copying machine 1 feeds the image reading unit that reads an image of the document, the image forming unit that forms the image read by the image reading unit on the sheet S, and the sheet S on which the image is to be formed. A sheet feeding unit and a sheet conveying unit that conveys the sheet S on which an image is formed by the image forming unit are configured. First, each means constituting the copying machine 1 will be described in detail.

  The image reading means includes a document table 2 fixed on the upper side of the copying machine 1, a document pressure plate 3 that presses a document placed on the document table 2, and a document table 2 below the document table 2. A lamp 4 for illuminating the placed and placed document; a CCD 11 for receiving a light image of the illuminated document; and reflecting mirrors 5, 6, 7 for guiding the light image to the CCD 11. The image of the document placed on the document table is read.

  The image forming means includes a recording means (not shown) for recording image data read by the image reading means, a photosensitive drum 12, and a charger 13 for uniformly charging the surface of the photosensitive drum 12. A laser scanner unit 9 that irradiates the surface of the photosensitive drum 12 charged by the charger 13 with laser light, and a toner image that is transferred from the electrostatic latent image formed by the laser light from the laser scanner unit 9 to the sheet S. The developing device 14 to be formed, the transfer charger 19 for transferring the toner image developed on the surface of the photosensitive drum 12 to the sheet S, and the sheet S on which the toner image has been transferred by the transfer charger 19 are separated. A separation charger 20 for transferring the toner image, and a cleaner 26 for removing the toner remaining on the photosensitive drum 12 after the toner image is transferred. The image read by the serial image reading means for forming the sheet S.

  The sheet feeding means is provided at the feeding cassettes 32 and 33 on which the sheets S are stacked and the leading ends of the feeding cassettes 32 and 33, and feeding units 34 and 36 for separating and feeding the sheets S one by one. And a double feed detecting device 35 provided downstream of the feeding units 34 and 36 as an abnormality detecting means for detecting double feeding of the sheet S, and a resist for adjusting the timing of the image forming operation of the image forming means and the sheet S. A roller 81, and a multi-feed sheet discharge valve 51 which is swingably provided in a sheet S feeding path connecting the multi-feed detecting device 35 and the registration roller 81, and discharges the multi-feed sheet S from the feeding path. And a multi-feed sheet discharge tray 53 on which the discharged sheets S are stacked.

  The multi-feed sheet discharge valve 51 swings in the E direction when discharging multi-feed sheets, which are abnormally fed, and in the F direction when feeding sheets to the image forming means, and the sheet S is arbitrarily selected. To the feed path. Reference numeral 52 denotes a discharge path through which the sheet S discharged by the multi-feed sheet discharge valve 51 is conveyed.

  The sheet conveying means is disposed on the downstream side of the image forming means, and conveys the sheet S on which the toner image has been transferred, and the image on the sheet S conveyed by the conveying means 21 is permanent. A fixing device 22 for fixing as an image, a discharge roller 24 for discharging the sheet S on which the toner image is fixed by the fixing device 22 from the copying machine 1, and a sheet S discharged by the discharge roller 24 are stacked. And a discharge tray 25 for conveying the sheet S on which an image is formed.

  Further, the sheet conveying means is disposed at the lower part of the fixing device 22 and is provided at a reversing path 37 for reversing the front and back of the sheet S, and at a junction of the discharge roller 24 and the reversing path 37. A discharge valve 41 supported so as to be swingable and guiding the sheet S to an arbitrary conveyance path, a duplex conveying path 38 for conveying the sheet S conveyed from the reversing path 37 to the image forming unit again, and the duplex conveying path. And a buffer path 39 as an intermediate tray on which sheets S are temporarily stacked.

  The discharge valve 41 swings in the B direction when the sheet S is conveyed to the discharge roller 24, and swings in the A direction when the sheet S is conveyed to the reversing path 37, so that the sheet S enters an arbitrary conveyance path. Transport.

  The buffer path 39 includes a buffer tray 111 on which sheets S are stacked, and a half-moon pickup roller that is rotatably supported to feed the sheets S stacked on the buffer tray 111 one by one from the bottom. 112, a feed roller 113 that carries the sheet S to the feeding path, and a retard roller 114 that is opposed to the feed roller 113 and is connected to a torque limiter (not shown) and is provided with a predetermined return torque. (See FIG. 2). The retard roller 114 is urged by a feed roller 113 by a compression spring (not shown), and can sequentially transport the sheets S temporarily stacked.

  Next, the double feed detection device 35 will be described in detail with reference to FIG. FIG. 3 is a schematic cross-sectional view of the double feed detection device 35. The double feed detection device 35 is disposed adjacent to a driving roller 104 that conveys the sheet S provided in the sheet S feeding path and a driven roller 103 that is disposed to face the driving roller 104. The drive roller 104 is rotatably supported and is rotationally driven by a motor (not shown). The driven roller 103 is also rotatably supported and is urged in the C direction by a compression spring (not shown).

  The multifeed detection device 35 includes a laser light emitting unit 100 that emits laser light, a laser light receiving unit 101 that receives laser light emitted by the laser light emitting unit 100, and the follow-up of light emission and light receiving directions of the laser light. And a prism 102 that adjusts to the roller 103, and irradiates the driven roller 103 with laser light when the sheet S passes between the driving roller 104 and the driven roller 103, whereby the sheet S is double-fed. Detect.

  When the sheet S passes between the driving roller 104 and the driven roller 103, the driven roller 103 is urged by a compression spring depending on the thickness of the sheet S and moves in the D direction. Further, when the sheet S passes between the driving roller 104 and the driven roller 103, the multi-feed detection device 35 irradiates the driven roller 103 with laser light, so that the thickness of the sheet S is adjusted according to the arrival time of the laser light. Can be detected. That is, if the sheet S to be fed is thick (multiple fed), the optical path lengths of the laser light emitting unit 100 and the laser light receiving unit 101 are shortened, and the arrival time of the laser light is shortened. The double feed detection device 35 compares the detected thickness of the sheet S with the thickness of the sheet S previously stored in the CPU, and detects whether or not it is double feed.

  Next, the sheet conveying operation of the copying machine 1 configured as described above will be described in detail with reference to FIGS. 4 to 11 are diagrams showing the sheet conveyance path in the copying machine 1, and the sheets S are conveyed in the order of S1 to S5. In order to simplify the description, detailed configurations such as the image reading means, the feeding cassettes 32 and 33, and the feeding unit 36 are omitted.

  FIG. 4 is a diagram illustrating a conveyance path of the sheet S when the sheet S is normally fed during double-sided image formation. The sheet (S1) fed from the feeding cassette is fed above the image forming unit (S2). After the timing with the image forming unit is adjusted by the registration roller 81, the image is transferred by the photosensitive drum 12 of the image reading unit, and the sheet S 3 is conveyed to the reverse path 37. The sheet S4 reversed by the reversing path 37 passes through the buffer path 39, is conveyed again to the position of the sheet S2, and images are formed on both sides. The sheet S5 having images formed on both sides is discharged out of the copying machine 1.

FIGS. 5 to 11 are diagrams illustrating a sheet conveyance path when a sheet is abnormally fed (double-fed) during double-sided image formation. FIG. 5 shows a state in which the multi-feed sheet is fed from the feed tray, and the double-feed sheet is shown as J.
When the multi-feed sheet J reaches the multi-feed detection device 35, the multi-feed detection device 35 detects the multi-feed by the thickness of the sheet, and indicates that the multi-feed sheet J is being fed to the CPU 40 of the copying machine 1. Communicate (see FIG. 6). By this communication, the CPU 40 swings the double feed sheet discharge valve 51 in the E direction. When the discharge valve 41 swings in the E direction, the discharge path 52 is opened, and the multi-feed sheet J is conveyed to the multi-feed sheet discharge tray 53 (see FIG. 7).

  When the multi-feed sheet J is discharged to the multi-feed sheet discharge tray 53, the sheet fed before the multi-feed sheet J (S4 shown in FIG. 7) adjusts the interval between the sheets. Wait on buffer path 39. Thereafter, the next sheet S6 of the multi-feed sheet J is fed from the feeding cassette (see FIG. 8). Further, when the sheet S3 arrives at the buffer path 39, the sheet S4 is waiting on the buffer path 39, so that the sheet S3 is stacked on top of the sheet S4.

  When the sheet S6 passes through the image forming means (see FIG. 9), the sheet S4 is restarted to form an image on both sides, and the sheet S4 is discharged out of the copying machine (see FIG. 10). Even if the sheet S4 is restarted, the sheet S3 stands by in the buffer path 39. Accordingly, the sheet S2 is stacked on top of the sheet S3. The sheet S3 restarts after the sheet S7 fed next to the sheet S6 passes through the image forming unit. When the sheet S3 is restarted, the sheet position returns to the normal state before the multi-feed sheet J is conveyed. As described above, when the multi-feed sheet J is fed, the multi-feed sheet J is discharged, and the conveyance of the sheet is adjusted using the buffer path 39 without stopping the image forming operation. The image forming operation can be continuously performed.

  As described above, according to the copying machine 1 according to the present embodiment, abnormally fed sheets can be discharged in the feeding path, so that image formation is stopped even when the sheets are abnormally fed. It is possible to perform image forming operations continuously without causing them to occur. In addition, since the buffer path 39 for temporarily stacking the sheets to be transported is provided, continuous operation that minimizes the decrease in productivity is achieved without stopping image formation of the entire apparatus even when multiple sheets are fed. Is possible.

  In addition, since a recording unit that records image data to be formed on a sheet is provided, it is possible to perform image formation again as necessary when abnormal feeding is performed, and continuous image formation can be performed. It becomes possible. Further, by adding a recording means for storing the image, it is possible to easily re-form the image, and the image forming operation can be quickly returned. Further, since the copying machine 1 has the discharge path 52 disposed upstream of the image forming unit, damage to the image forming unit and the fixing unit by the multi-feed sheet J can be eliminated.

  The copying machine 1 temporarily holds the sheet S by using the buffer path 39 as an intermediate tray. However, the present invention is not limited to the above-described configuration, and a temporary sheet is temporarily stored in the sorter instead of the buffer path 39. A holding means may be provided. In addition, although the present embodiment has been described by exemplifying the double feed detection device as the abnormality detection means, the sheet skew detection device and the sheet material corner detection device are respectively disposed to detect the sheet abnormality. May be.

1 is a schematic cross-sectional view of a copying machine 1 according to the present embodiment. 3 is a schematic cross-sectional view of a buffer path 39 of the copying machine 1. FIG. 2 is a schematic cross-sectional view of a multifeed detection device 35 of the copying machine 1. FIG. FIG. 6 is a diagram illustrating a sheet conveyance path of the copying machine 1 (at the time of normal feeding). FIG. 6 is a diagram illustrating a sheet conveyance path of the copying machine 1 (at the time of abnormal feeding). FIG. 6 is a diagram illustrating a sheet conveyance path of the copying machine 1 (at the time of abnormal feeding). FIG. 6 is a diagram illustrating a sheet conveyance path of the copying machine 1 (at the time of abnormal feeding). FIG. 6 is a diagram illustrating a sheet conveyance path of the copying machine 1 (at the time of abnormal feeding). FIG. 6 is a diagram illustrating a sheet conveyance path of the copying machine 1 (at the time of abnormal feeding). FIG. 6 is a diagram illustrating a sheet conveyance path of the copying machine 1 (at the time of abnormal feeding). FIG. 6 is a diagram illustrating a sheet conveyance path of the copying machine 1 (at the time of abnormal feeding).

Explanation of symbols

1 Copying machine (image forming device)
35 Double feed detection device (abnormality detection means)
51 Sheet discharge means (multifeed sheet discharge valve)
S sheet J Double feed sheet

Claims (6)

Recording means for recording image data, image forming means for forming image data recorded in the recording means on a sheet, sheet feeding means for separating and feeding sheets one by one to the image forming means, An image forming apparatus comprising: a sheet conveying unit that conveys a sheet on which an image is formed by the image forming unit;
The sheet feeding path of the sheet fed by the sheet feeding means includes an abnormality detecting means for detecting abnormal sheet feeding, and a sheet for which abnormal feeding is detected by the abnormality detecting means from the feeding path. An image forming apparatus comprising: a sheet discharge unit that discharges the sheet.   The sheet discharging means is provided swingably with respect to the feeding path, and discharges abnormally fed sheets from the feeding path based on detection of abnormal feeding by the abnormality detecting means. The image forming apparatus according to claim 1.   3. The intermediate tray that temporarily holds at least one sheet to be conveyed is provided in a conveyance path of the sheet conveyed by the sheet conveying unit. Image forming apparatus.   4. The image forming apparatus according to claim 1, wherein the abnormality detection unit detects double feeding, which is a state in which two sheets overlap each other. 5.   4. The image forming apparatus according to claim 1, wherein the abnormality detection unit detects an oblique feeding in which the sheet is inclined with respect to the feeding path. 5.   4. The image forming apparatus according to claim 1, wherein the abnormality detection unit detects a corner bend in a state where at least a corner of the sheet is bent. 5.

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