JP2019131388A - Paper feeding device and image formation system - Google Patents

Abstract

To provide a paper feeding device and an image formation system that are capable of well performing paper separation when sucking and transporting the paper.SOLUTION: A large volume paper feeding device includes: a sucking and transporting part 220 that sucks and transports paper loaded on the paper loading table; and a controlling part that controls the sucking and transporting part 220. The sucking and transporting part 220 is equipped with a sucking area that sucks paper along the paper width direction. The controlling part controls distribution of the sucking amount in the paper width direction based on the rigidity of the paper and the paper width.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a sheet feeding device and an image forming system.

  In recent years, an image forming system that performs a series of various processes including image formation is known. This image forming system is configured by arranging one or more devices in series according to specifications required by a user. As an apparatus constituting the image forming system, in addition to an image forming apparatus that forms an image, a paper feeding device (large capacity paper feeding device) that holds a large volume of paper and feeds it to the image forming apparatus can be cited. It is done.

  The paper feeding device includes a paper feeding unit that feeds paper. The paper fed from the paper feed unit is transported along the transport path and discharged outside the apparatus. As a result, the sheet is fed to an apparatus connected downstream, for example, an image forming apparatus. In the paper feeding device, a paper mounting table is prepared, and a sheet bundle composed of a plurality of papers is mounted on the paper mounting table. The paper feeding unit feeds the paper located at the top of the paper stack placed on the paper placement table one by one. As this type of paper feeding unit, one that sucks and conveys paper is known.

  For example, Patent Documents 1 to 3 disclose a technique for improving the separation performance between the uppermost sheet and the second and subsequent sheets. These patent documents disclose the contents of bending the sucked paper (uppermost paper) by providing a concavo-convex shape in the suction transport unit that sucks and transports the paper. According to this method, a gap is formed between the uppermost sheet and the second sheet, and separation air is introduced into the gap, so that the sheet can be separated satisfactorily.

  Further, for example, Patent Documents 4 and 5 disclose a method of changing the suction area according to the paper width that is the paper size in the paper width direction.

JP-A-6-107347 JP 2006-327778 A JP-A-6-255815 JP-A-6-144617 JP 2010-241590 A

  However, in the methods described in Patent Documents 4 and 5, since the sheet is sucked in a wide range in the sheet width direction, the sheet is adsorbed in a plane. Therefore, there is a problem that a gap is hardly generated between the uppermost sheet and the second sheet, and the sheet is not separated well. This problem is also affected by the stiffness of the paper.

  In addition, in the method using the uneven shape of the suction conveyance unit as in Patent Documents 1 to 3, since the large uneven shape is necessary to bend the paper, the uneven shape causes deformation of the paper. There is a possibility that. When the paper is deformed, the paper may be wrinkled during the transport process, or the paper position may not be properly regulated and the paper transport may be offset. In addition, it is necessary to design the shape of the guide member that guides the conveyance of the paper in consideration of the deformation of the paper, but in this case, the paper or thin paper that is curled cannot enter the guide member, Incorrect conveyance may occur.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide a paper feeding device and an image forming system that can perform good separation of the paper when the paper is sucked and conveyed. .

  In order to solve this problem, one aspect of the present invention provides a paper feeding device that feeds paper from a paper placement table on which a bundle of paper is placed. The sheet feeding device includes a suction conveyance unit that sucks and conveys the uppermost sheet in a bundle of sheets placed on a sheet placement table, and a control unit that controls the suction conveyance unit. In this case, the suction conveyance unit includes a suction region that sucks the sheet in the sheet width direction orthogonal to the sheet conveyance direction, and the control unit is based on the sheet width that is the sheet stiffness in the sheet width direction and the sheet size in the sheet width direction. The suction amount distribution in the paper width direction is controlled.

  Another aspect of the present invention provides a paper feeding device that feeds paper from a paper placement table on which a bundle of paper is placed. The sheet feeding device includes a suction conveyance unit that sucks and conveys the uppermost sheet in a bundle of sheets placed on a sheet placement table, and a control unit that controls the suction conveyance unit. In this case, the suction conveyance unit includes a suction region for sucking the paper in the paper width direction orthogonal to the paper conveyance direction, and the control unit is located at both ends of the paper more than the suction amount of the first suction region corresponding to the center of the paper. The distribution of the suction amount in the paper width direction is controlled so that the suction amount in the corresponding second suction region becomes small.

  According to another aspect of the present invention, a sheet feeding device that feeds a sheet from a sheet placing table on which a bundle of sheets is placed, an image forming apparatus that forms an image on a sheet fed from the sheet feeding device, An image forming system including a paper feeding device and a control unit that controls the image forming device is provided. The sheet feeding device has a suction conveyance unit that sucks and conveys the uppermost sheet of the sheet bundle placed on the sheet placement table. In this case, the suction conveyance unit includes a suction region that sucks the sheet in the sheet width direction orthogonal to the sheet conveyance direction, and the control unit is based on the sheet width that is the sheet stiffness in the sheet width direction and the sheet size in the sheet width direction. The suction amount distribution in the paper width direction is controlled.

  Here, in the present invention, the controller controls the suction amount in the sheet width direction so that the suction amount in the second suction area corresponding to both ends of the sheet is smaller than the suction amount in the first suction area corresponding to the center of the sheet. It is preferable to control the distribution.

  In this case, it is desirable that the control unit does not perform suction in the second suction region.

  Moreover, in this invention, it is preferable that the ventilation part which ventilates toward a paper is connected to the suction conveyance part. The control unit preferably sucks the paper in the first suction area and blows air toward the paper in the second suction area.

  In this case, it is preferable that the control unit starts air blowing in the second suction area after the uppermost sheet is adsorbed by the suction conveyance unit.

  Moreover, it is preferable that the present invention further includes a leading end air blowing unit that blows air to the sheet bundle from the leading end side of the sheet in the sheet conveying direction. And it is desirable for a control part to start ventilation of a 2nd suction area | region before starting the ventilation by a front-end | tip ventilation part.

  In addition, it is preferable that the control unit reduce the blowing amount of the second suction area as the stiffness of the sheet is smaller.

  Further, it is preferable that the control unit reduce the air blowing amount in the second suction area as the paper width is larger.

  In the present invention, it is preferable that the air flow rate in the second suction area is set such that the air flow rate on the paper rear end side in the paper transport direction is smaller than the air flow rate on the paper front end side.

  In the present invention, it is preferable that the control unit expands the range of the first suction area toward both ends of the sheet as the rigidity of the sheet decreases.

  In the present invention, it is preferable that the control unit expands the range of the first suction area toward both ends of the sheet as the sheet width increases.

  Further, it is desirable that the suction conveyance unit has a convex shape such that the center of the sheet is larger than both ends of the sheet with respect to the distance to the uppermost sheet.

  According to the present invention, it is possible to satisfactorily separate the paper when the paper is sucked and conveyed.

1 is a front view schematically showing a configuration of an image forming system according to a first embodiment. Front view schematically showing the configuration of the paper feed unit Top view schematically showing the configuration of the suction transfer unit Explanatory drawing schematically showing the configuration of the suction transfer unit 6 is a flowchart illustrating a paper feeding procedure by the paper feeding unit according to the first embodiment. Explanatory drawing which shows the relationship between the 1st suction area and the 2nd suction area, and an opening part. Explanatory drawing which shows typically the structure of the suction conveyance part which concerns on 2nd Embodiment. 7 is a flowchart showing a paper feeding procedure by a paper feeding unit according to the second embodiment. Explanatory drawing which shows the relationship between the 1st suction area and the 2nd suction area, and an opening part. Explanatory drawing which shows the relationship between the 1st suction area and the 2nd suction area, and an opening part. Explanatory drawing which shows the modification of a suction conveyance part Explanatory drawing which shows the modification of a suction conveyance part

(First embodiment)
FIG. 1 is a front view schematically showing the configuration of the image forming system according to the present embodiment. The image forming system is a system that performs predetermined processing including image formation on the paper P that is transported along a transport path, and is configured by a plurality of devices arranged in series. The image forming system according to this embodiment includes an image forming apparatus 100 and a large-capacity paper feeding apparatus 200. These apparatuses are arranged in the order of the large-capacity sheet feeding device 200 and the image forming apparatus 100 from the upstream side to the downstream side in the sheet conveyance direction.

  The image forming apparatus 100 is an apparatus that forms an image on the paper P fed from the large-capacity paper feeding device 200 or the paper P held by itself. The image forming apparatus 100 is, for example, an electrophotographic image forming apparatus, and forms a full-color image by arranging a plurality of photoconductors facing a single intermediate transfer belt in a vertical direction, so-called tandem type. A color image forming apparatus. The image forming apparatus 100 is mainly composed of a document reading device SC, four sets of image forming units 10Y, 10M, 10C, and 10K, a fixing device 40, and a control unit 50. These elements are one element. Housed in a housing.

  The document reader SC scans and exposes the document with the exposure device, reads the reflected light with the line image sensor, and obtains an image signal. The image signal is subjected to processing such as A / D conversion, shading correction, and compression, and then input to the control unit 50 as image data. Note that the image data input to the control unit 50 is not limited to the data read by the document reading device SC. For example, the image data received from a personal computer connected to the image forming device 100, another image forming device, or It may be read from a portable recording medium such as a semiconductor memory.

  The four image forming units 10Y, 10M, 10C, and 10K include an image forming unit 10Y that forms a yellow (Y) image, an image forming unit 10M that forms a magenta (M) image, and a cyan (C) image. The image forming unit 10 </ b> C to be formed and the image forming unit 10 </ b> K that forms a black (K) image are configured.

  The image forming unit 10Y includes a photosensitive drum 11Y and a charging unit, an optical writing unit, a developing device, and a drum cleaner arranged around the photosensitive drum 11Y. The surface of the photosensitive drum 11Y is uniformly charged by the charging unit, and a latent image is formed on the photosensitive drum 11Y by scanning exposure by the optical writing unit. The developing device develops the latent image on the photosensitive drum 11Y by developing with toner. As a result, an image (toner image) corresponding to yellow is formed on the photosensitive drum 11Y. The image formed on the photosensitive drum 11Y is sequentially transferred to a predetermined position on the intermediate transfer belt 15 which is an endless belt by a primary transfer roller.

  The remaining image forming units 10M, 10C, and 10K are composed of the photosensitive drums 11M, 11C, and 11K, and a charging unit, an optical writing unit, a developing device, and a drum cleaner arranged around the photosensitive drums 11M, 11C, and 11K. Is the same as that of the image forming unit 10Y.

  The image transferred onto the intermediate transfer belt 15 is transferred by the secondary transfer roller 16 to the paper P transported at a predetermined timing by the paper transport unit 20. The secondary transfer roller 16 is disposed in pressure contact with the intermediate transfer belt 15, and a transfer nip is formed between the secondary transfer roller 16 and the intermediate transfer belt 15.

  The paper transport unit 20 transports the paper P fed from the paper tray 21 by the paper feed roller 22 or the paper P fed from the large-capacity paper feeder 200 according to the transport path. The paper transport unit 20 includes a transport roller, a transport guide, and the like. A paper discharge roller 23 and a switching gate 24 described later also constitute a part of the paper transport unit 20.

  The fixing device 40 is a device that performs a fixing process on the paper P onto which the image has been transferred. The fixing device 40 includes, for example, a pair of fixing rollers that are pressed against each other to form a fixing nip, and a heater that heats one of the fixing rollers. The fixing device 40 fixes the transferred image onto the paper P using the pressure of the pair of fixing rollers and the heat of the fixing roller while the paper P passes through the fixing nip. The paper P on which the fixing process has been performed is discharged out of the apparatus by the paper discharge roller 23.

  When image formation is performed also on the back surface of the paper P, the paper P on which image formation on the front surface of the paper has been completed is conveyed to the refeed conveyance path by the switching gate 24. In the re-feed conveyance route, the rear end of the conveyed paper P is nipped by the reverse roller, and then reversely fed to reverse the front and back of the paper P. The paper P whose front and back are reversed is transported by a plurality of transport rollers, and is joined to a transport path on the upstream side of the secondary transfer roller 16 for use in image formation on the back surface of the paper.

  The control unit 50 controls the operation of the image forming apparatus 100. As the control unit 50, a microcomputer mainly composed of a CPU, a ROM, a RAM, and an I / O interface can be used. The CPU controls the operation of the image forming apparatus 100 by executing various programs (processor). The ROM stores various programs executed by the CPU in the form of program codes readable by the CPU. The ROM stores data necessary for program execution. The RAM is a memory serving as a working storage area. The program and data stored in the ROM are expanded on the RAM when read by the CPU. The CPU performs various processes based on the program and data developed on the RAM.

  The operation panel 60 is an input unit capable of inputting desired information according to information displayed on the display. As the operation panel 60, a touch panel method or the like can be adopted. The user can set the contents of the job (information about the paper P (paper size, paper type, etc.), image density, magnification, etc.) through an operation on the operation panel 60. The set information is acquired by the control unit 50. The operation panel 60 also functions as a display unit that displays various information to the user by being controlled by the control unit 50.

  The large-capacity paper feeding device 200 is a device that feeds the paper P. The large-capacity paper feeding device 200 includes one or more paper feeding units 210, for example, three paper feeding units 210 arranged in an upper stage, a middle stage, and a lower stage, and a control unit 250. Housed in a housing.

  FIG. 2 is a front view schematically showing the configuration of the paper feed unit 210. The paper feeding unit 210 accommodates a plurality of sheets P (sheet bundle) and feeds the uppermost sheet P of the accommodated sheet bundles to the transport path. The sheet feeding unit 210 is mainly configured by a sheet mounting table 211, a leading end regulating member 212, a trailing end regulating member 213, a suction conveyance unit 220, a leading end blowing unit 230, and a side end blowing unit 240.

  In the paper feeding unit 210, the paper bundle is placed on the paper placement table 211. The paper mounting table 211 is provided with an electric lifting mechanism, and is configured to be lifted and lowered along the vertical direction. Further, a guide rail 214 is provided on the sheet mounting table 211 and is configured to be able to be pulled out from the large capacity sheet feeding device 200.

  The leading edge regulating member 212 regulates the leading edge of the sheet bundle on the sheet placing table 211. The leading end regulating member 212 is fixed to the main body of the large capacity sheet feeding device 200.

  The trailing edge regulating member 213 regulates the trailing edge of the sheet bundle on the sheet placing table 211. The rear end regulating member 213 is configured to be movable along the paper transport direction, and its position is adjusted according to the paper size in the paper transport direction.

  The rear end regulating member 213 is provided with a height sensor (not shown) that detects the height of the sheet bundle placed on the sheet placing table 211. The controller 250 drives the lifting mechanism based on the signal from the height sensor, and controls the lifting / lowering of the sheet placing table 211. By this control, the uppermost sheet P of the sheet bundle placed on the sheet placing table 211 is maintained at a constant height.

  The suction conveyance unit 220 is disposed above the paper placement table 211 (paper P) so as to face the paper placement table 211. The suction conveyance unit 220 sucks and conveys the uppermost sheet P in the bundle of sheets placed on the sheet placing table 211.

  The suction conveyance unit 220 is mainly composed of a conveyance unit 221 and a suction unit 226. Here, FIG. 3 is a top view schematically showing the configuration of the suction conveyance unit 220. FIG. 4 is an explanatory diagram schematically showing the configuration of the suction conveyance unit 220.

  The transport unit 221 has a function of transporting the paper P and is composed of an endless belt member. In the present embodiment, the transport unit 221 includes five belt members 221a to 221e that are arranged adjacent to each other in the paper width direction orthogonal to the paper transport direction, and each belt member 221a to 221e is a paper sheet. Arranged along the transport direction.

  The individual belt members 221a to 221e are stretched over large-diameter driving rollers 223a to 223e connected to a driving source, and two driven rollers 224a to 224e and 225a to 225e. The driving rollers 223a to 223e are disposed on the upstream side in the paper transport direction, and the two driven rollers 224a to 224e and 225a to 225e are disposed on the downstream side in the paper transport direction and spaced apart from each other.

  The individual belt members 221a to 221e are rotated when the driving rollers 223a to 223e are rotationally driven, and the suction surface (belt region located on the lower side) facing the paper P is moved in the paper transport direction. The drive rollers 223a to 223e are rotationally driven in synchronization, and the individual belt members 221a to 221e are also rotated in synchronization. Each belt member 221a to 221e is provided with a plurality of through holes (not shown) each having a small diameter.

  The suction unit 226 has a function of sucking the uppermost sheet P and sucking it on the belt members 221a to 221e. The suction unit 226 is disposed inside the belt members 221a to 221e serving as the transport unit 221, and faces the paper placement table 211 (paper P) via the belt members 221a to 221e (suction surface).

  The suction part 226 is mainly composed of a suction fan 227 and a duct 228.

  The suction fan 227 is a fan that sucks air.

  The duct 228 is a duct to which the suction fan 227 is connected and guides air to the suction fan 227. The duct 228 is disposed inside the belt members 221a to 221e so as to intersect the individual belt members 221a to 221e. Five openings 228a to 228e are provided on the lower surface of the duct 228, that is, the surface facing the paper placing table 211 (paper P) via the belt members 221a to 221e. The five openings 228a to 228e are provided adjacent to each other in the paper width direction so as to correspond to the five belt members 221a to 221e. A plurality of internal flow paths corresponding to the individual openings 228a to 228e are provided inside the duct 228. The individual internal flow paths are provided with valve bodies 229a to 229e for blocking communication between the common flow path of the duct 228 connected to the suction fan 227 and the internal flow path.

  In the suction conveyance unit 220 having such a configuration, air is drawn into the duct 228 through the individual openings 228a to 228e when the suction fan 227 operates. Thereby, the individual openings 228a to 228e function as a suction area for sucking the paper P. On the other hand, when the valve bodies 229a to 229e are set to the closed state, the internal flow paths leading to the openings 228a to 228e are blocked. In this case, suction is not performed in the openings 228a to 228e. Therefore, the distribution of the suction amount in the paper width direction can be controlled by individually setting the opening and closing of the valve bodies 229a to 229e.

  Please refer to FIG. 1 and FIG. 2 again. The front air blowing unit 230 is arranged on the front side of the sheet bundle and in the vicinity of the suction conveyance unit 220. The leading edge blowing unit 230 has a function of blowing the uppermost sheet P and the second and subsequent sheets P by blowing air from the sheet leading end side to the sheet bundle placed on the sheet placing table 211. Yes. The tip blower 230 is configured mainly with a blower 231 and a blower opening 232.

  The blower 231 is, for example, a multiblade fan (sirocco fan). The air outlet 232 is a part for blowing the wind output from the blower 231 toward the upper part of the sheet bundle.

  The side end blower 240 is disposed on the side of the sheet mounting table 211. The side end blower 240 has a function of floating the uppermost sheet P by blowing air to the side end parallel to the sheet conveyance direction in the bundle of sheets placed on the sheet placing table 211. In this embodiment, a set of side-end air blowing units 240 is prepared, and these side-end air blowing units 240 are arranged to face each other with a sheet bundle interposed therebetween. Each side end air blower 240 has the same configuration as that of the tip air blower 230, and is mainly composed of a blower 241 and a blower opening 242.

  The blower 241 is, for example, a multiblade fan (sirocco fan). The blower opening 242 is a part for blowing the wind output from the blower 241 toward the upper part of the sheet bundle.

  The control unit 250 controls the operation of the large capacity sheet feeding device 200. As the control unit 250, a microcomputer mainly composed of a CPU, a ROM, a RAM, and an I / O interface can be used. The CPU controls the operation of the large-capacity paper feeder 200 by executing various programs (processor). The ROM stores various programs executed by the CPU in the form of program codes readable by the CPU. The ROM stores data necessary for program execution. The RAM is a memory serving as a working storage area. The program and data stored in the ROM are expanded on the RAM when read by the CPU. The CPU performs various processes based on the program and data developed on the RAM.

  The control unit 250 controls the suction conveyance unit 220, the leading end blowing unit 230, and the side end blowing unit 240 to suck and convey the uppermost sheet P out of the sheet bundle placed on the sheet placing table 211. . In relation to the present embodiment, the control unit 250 controls the distribution of the suction amount in the paper width direction based on the stiffness of the paper P and the paper width that is the paper size in the paper width direction.

  Detection signals from various sensors are input to the control unit 250. The sheet adsorption sensor 251 is a sensor that detects adsorption of the sheet P to the suction conveyance unit 220 (conveyance unit 221) (see FIG. 3). Further, the paper detection sensor 252 is disposed in the vicinity of the transport roller 201 to which the paper P sent out from the paper supply unit 210 first arrives, and detects that the leading edge of the paper P has reached the transport roller 201. (See FIG. 1). In addition, the control unit 250 can communicate with the control unit 50 of the image forming apparatus 100.

  Hereinafter, the operation of the large-capacity paper feeder 200 according to the present embodiment will be described. Here, FIG. 5 is a flowchart showing a paper feeding procedure by the paper feeding unit 210. The process shown in this flowchart is executed by the control unit 250 using, for example, paper feed start information input from the image forming apparatus 100 as a trigger. In the following description, the terms “paper center” and “paper both ends” are used to refer to the paper center and both paper edges in the paper width direction unless otherwise specified. Further, the center of the sheet and both ends of the sheet relatively indicate areas in the sheet, and do not indicate only specific areas of the sheet P in an absolute sense.

  First, in step S <b> 1, the control unit 250 acquires information about the paper P that is a paper supply target. In the relationship with the present embodiment, the rigidity of the paper P and the paper width correspond to this. For example, the image forming apparatus 100 holds information about the paper P stored in the paper supply unit 210, and the control unit 250 acquires the information about the paper P from the image forming apparatus 100. Note that the information about the paper P stored in each paper feed unit 210 may be held by the large-capacity paper feeder 200 itself.

  In step S <b> 2, the control unit 250 sets the distribution of the suction amount by the suction conveyance unit 220 based on the stiffness of the paper P and the paper width. Usually, the suction amount in the paper width direction is set uniformly. On the other hand, in this embodiment, the distribution of the suction amount in the paper width direction is controlled based on the stiffness of the paper P and the paper width.

  FIG. 6 is an explanatory diagram showing the relationship between the first suction region R1 and the second suction region R2 and the openings 228a to 228e. In the control according to the present embodiment, suction is performed in the first suction region R1 corresponding to the center of the sheet, and suction is not performed in the second suction region R2 corresponding to both ends of the sheet. The distribution of the suction amount is controlled through the setting modes of the first suction region R1 and the second suction region R2.

  Specifically, the central opening 228c is set as the first suction region R1. On the other hand, the two openings 228b and 228d located on both sides of the central opening 228c and the two openings 228a and 228e located at both ends are in accordance with the stiffness of the paper P and the paper width, and the first suction region R1. Alternatively, it is set as the second suction region R2. In this case, the openings 228a to 228e corresponding to the first suction region R1 are set in the open state of the valve bodies 229a to 229e, and the openings 228a to 228e corresponding to the second suction region R2 are set to the valve bodies 229a to 229e. Is set to the closed state.

  First, a sheet P having a small sheet width is shown in FIG. The central opening 228c is set as the first suction region R1. On the other hand, the remaining openings 228a, 228b, 228d, 228e are set as the second suction region R2. That is, in the distribution of the suction amount, the central opening 228c is in the suction state, and the remaining openings 228a, 228b, 228d, and 228e are in the non-suction state.

  FIG. 6B shows the paper P having a large paper width. The central opening 228c and the two adjacent openings 228b and 228d are set as the first suction region R1. On the other hand, the two openings 228a and 228e located at both ends are set as the second suction region R2. That is, in the distribution of the suction amount, the central opening 228c and the two adjacent openings 228b and 228d are in the suction state, and the remaining openings 228a and 228e are in the non-suction state.

  In this way, regardless of the paper width, suction is performed in the first suction region R1 corresponding to the center of the paper, and suction is not performed in the second suction region R2 corresponding to both ends of the paper. Therefore, when the sheet P is attracted to the suction conveyance unit 220, since suction is not performed in the second suction region R2, both ends of the sheet hang down. Due to the sagging of both ends of the sheet, a gap is formed between the uppermost sheet P and the second sheet P, and the separation air from the front fan section 230 is separated from the uppermost sheet P and the second sheet P. Can be sent in between. As a result, the separation of the paper P can be performed satisfactorily.

  For the paper P having a large paper width, the two openings 228b and 228d located on both sides of the central opening 228c are also set as the first suction region R1. That is, in the paper P having a large paper width, the range of the first suction region R1 is expanded toward the paper edge portion side compared to the paper P having a small paper width. The larger the paper width, the more affected by its own weight, the more drooping the both ends of the paper becomes. However, the range of the first suction region R1 is expanded and the range of the second suction region R2 is reduced, so Extreme drooping can be suppressed. Thereby, when the paper P is fed, the situation of interference with the guide member is suppressed, and the paper P can be fed appropriately.

  In addition, the setting of the first suction region R1 and the second suction region R2 differs depending on the rigidity even if the paper width is the same. Here, a description will be given by taking the paper P having a small paper width as an example.

  First, the paper P having a high stiffness is shown in FIG. 6A, as with the paper P having a small paper width. The central opening 228c is set as the first suction region R1. On the other hand, the remaining openings 228a, 228b, 228d, 228e are set as the second suction region R2. That is, in the distribution of the suction amount, the central opening 228c is in the suction state, and the remaining openings 228a, 228b, 228d, and 228e are in the non-suction state.

  On the other hand, the paper P having a low stiffness is shown in FIG. The central opening 228c and the two adjacent openings 228b and 228d are set as the first suction region R1. On the other hand, the two openings 228a and 228e located at both ends are set as the second suction region R2. That is, in the distribution of the suction amount, the central opening 228c and the two adjacent openings 228b and 228d are in the suction state, and the remaining openings 228a and 228e are in the non-suction state.

  In this way, suction is performed in the first suction region R1 corresponding to the center of the sheet, and suction is not performed in the second suction region R2 corresponding to both ends of the sheet, regardless of the stiffness. Therefore, when the sheet P is attracted to the suction conveyance unit 220, since suction is not performed in the second suction region R2, both ends of the sheet hang down. Due to the sagging of both ends of the sheet, a gap is formed between the uppermost sheet P and the second sheet P, and the separation air from the front fan section 230 is separated from the uppermost sheet P and the second sheet P. Can be sent in between. As a result, the separation of the paper P can be performed satisfactorily.

  For the paper P having a low stiffness, the two openings 228b and 228d located on both sides of the central opening 228c are also set as the first suction region R1. That is, in the paper P with a low stiffness, the range of the first suction region R1 is expanded toward the paper edge side compared to the paper P with a high stiffness. The lower the stiffness, the weaker the paper P, so that the amount of sag at both ends of the paper becomes more prominent. However, the range of the first suction region R1 is enlarged and the range of the second suction region R2 is reduced, so that both ends of the paper are reduced. Can be suppressed. Thereby, when the paper P is fed, the situation of interference with the guide member is suppressed, and the paper P can be fed appropriately.

  In step S <b> 3, the control unit 250 starts suction by the suction unit 226 and starts blowing by the side end blowing unit 240. The suction by the suction unit 226 is executed according to the first suction region R1 and the second suction region R2 set in step S2. The uppermost sheet P of the sheet bundle placed on the sheet placing table 211 is lifted against its own weight by the air blow by the side end blower 240 and the suction by the suction part 226.

  In step S <b> 4, the control unit 250 determines whether or not the uppermost sheet P is attracted to the transport unit 221. This determination is made with reference to the paper suction sensor 251. If the uppermost sheet P is attracted to the transport unit 221, an affirmative determination is made in step S4, and the process proceeds to step S5. On the other hand, if the uppermost sheet P is not attracted to the transport unit 221, a negative determination is made in step S4, and the process returns to step S4.

  In step S <b> 5, the control unit 250 starts the blowing of the tip blowing unit 230. Due to the air blow from the tip blower 230, wind (separation wind) flows between the uppermost paper P and the lower paper P (second paper P from the top). As a result, even when the second sheet P follows the uppermost sheet P adsorbed by the transport unit 221, the second sheet P is separated from the uppermost sheet P.

  In step S <b> 6, the control unit 250 starts driving the transport unit 221 and starts transporting the paper P. Specifically, the control unit 250 rotationally drives the belt members 221a to 221e of the transport unit 221. As a result, the uppermost sheet P sucked by the suction conveyance unit 220 is sent out to the conveyance path.

  In step S <b> 7, the control unit 250 determines whether the paper P has reached the transport roller 201. This determination is made with reference to the paper detection sensor 252. When the paper P reaches the transport roller 201, an affirmative determination is made in step S7, and the process proceeds to step S8. On the other hand, if the paper P has not reached the transport roller 201, a negative determination is made in step S7, and the process returns to step S7.

  In step S <b> 8, the control unit 250 stops driving the transport unit 221 and stops blowing the tip blowing unit 230.

  In step S9, the control unit 250 determines whether there is a next sheet P to be transported. If there is a next sheet P, an affirmative determination is made in step S9, and the process returns to step S4. On the other hand, if there is no next paper P, a negative determination is made in step S9, and this routine is terminated.

  As described above, the large-capacity paper feeding device 200 according to this embodiment includes the suction conveyance unit 220 that sucks and conveys the paper P placed on the paper placement table 211, and the control unit 250 that controls the suction conveyance unit 220. ,have. Here, the suction conveyance unit 220 includes a suction region that sucks the paper P along the paper width direction. The control unit 250 controls the distribution of the suction amount in the paper width direction based on the stiffness of the paper P and the paper width.

  According to this configuration, the suction amount can be set for each region in the paper P by controlling the distribution of the suction amount in the paper width direction. Thereby, the shape of the paper P adsorbed by the suction conveyance unit 220 can be controlled. As a result, a gap can be secured between the uppermost sheet P and the second sheet P, so that the sheet P can be separated satisfactorily.

  In the present embodiment, the control unit 250 performs suction in the first suction region R1 corresponding to the center of the sheet, and does not perform suction in the second suction region R2 corresponding to both ends of the sheet.

  According to this configuration, when the paper P is attracted to the suction conveyance unit 220, suction is not performed in the second suction region R2, so that both ends of the paper hang down. Due to the sagging of both ends of the sheet, a gap can be formed between the uppermost sheet P and the second sheet P in the center in the sheet width direction. Thereby, since the separation wind from the front blower 230 can be sent between the uppermost sheet P and the second sheet P, the sheet P can be separated satisfactorily.

  In the present embodiment, a method in which suction is not performed in the second suction region R2 has been described. However, the control unit 250 may control the suction amount distribution in the paper width direction so that the suction amount in the second suction region R2 is smaller than the suction amount in the first suction region R1. Even with such a configuration, the amount of suction at both ends of the sheet is small, so that the effect of sagging at both ends of the sheet can be obtained.

  In the present embodiment, the method of controlling the distribution of the suction amount in the paper width direction based on both the stiffness of the paper P and the paper width has been described. However, in the large-capacity paper feeding apparatus 200 according to the present embodiment, the suction amount distribution in the sheet width direction is such that the suction amount in the second suction region R2 is smaller than the suction amount in the first suction region R1. If controlled, control may be performed based on at least one of the stiffness of the paper P and the paper width.

  Further, in the present embodiment, the control unit 250 increases the range of the first suction region R1 toward both ends of the sheet as the rigidity of the sheet P is smaller.

  The lower the stiffness, the weaker the paper P, so that the drooping of both ends of the paper becomes more prominent. However, by enlarging the range of the first suction region R1, it is possible to suppress the dripping of both ends of the paper. Thereby, when the paper P is fed, the situation of interference with the guide member is suppressed, and the paper P can be fed appropriately.

  In the present embodiment, the control unit 250 increases the range of the first suction region R1 toward both ends of the sheet as the sheet width increases.

  The larger the paper width, the greater the influence of its own weight, so that the drooping of both ends of the paper becomes more conspicuous. Thereby, when the paper P is fed, the situation of interference with the guide member is suppressed, and the paper P can be fed appropriately.

(Second Embodiment)
The image forming system according to the second embodiment will be described below. The image forming system according to the present embodiment is different from that of the first embodiment in that air is blown toward the paper P in the second suction region R2. The description overlapping with the first embodiment will be omitted, and the description will be made focusing on the differences.

  FIG. 7 is an explanatory diagram schematically showing the configuration of the suction conveyance unit 220 according to the second embodiment. In the present embodiment, the suction conveyance unit 220 is provided with a blower 260 that blows air toward the paper P. As the blower 260, for example, a multiblade fan (sirocco fan) can be used. The blower 260 is connected to the duct 228 with a required structure, and communicates with individual internal flow paths leading to the five openings 228a to 228e. By driving the blower 260, the air sent out from the blower 260 is blown out from the openings 228 a to 228 e after passing through the duct 228. Thereby, it can blow toward the paper P. The air blow to the paper P becomes a flow of air in the reverse direction compared to the suction to the paper P, and corresponds to the suction defined in the minus direction (reverse direction). In other words, the blown air amount corresponds to the suction amount defined as minus.

  In addition, a valve body (not shown) is provided at a communication portion between each internal flow path and the blower 260. When this valve body is set to the closed state, the internal flow paths leading to the openings 228a to 228e are blocked. In this case, air blowing from the openings 228a to 228e is not performed.

  As one of the features of this embodiment, the control unit 250 sucks the paper P in the first suction region R1 and blows air toward the paper P in the second suction region R2.

  Hereinafter, the operation of the large-capacity paper feeder 200 according to the present embodiment will be described. Here, FIG. 8 is a flowchart showing a paper feeding procedure by the paper feeding unit 210. The process shown in this flowchart is executed by the control unit 250 using, for example, paper feed start information input from the image forming apparatus 100 as a trigger. In addition, since each process of step S21, S23, S24, S26-S28, S30 respond | corresponds to each process of step S1, S3-S7, S9 shown in 1st Embodiment, the detailed description is abbreviate | omitted. To do.

  In step S <b> 22, the control unit 250 sets the distribution of the suction amount by the suction conveyance unit 220 based on the stiffness of the paper P and the paper width. Usually, the suction conveyance unit 220 performs suction in the entire area in the paper width direction. On the other hand, in this embodiment, the distribution of the suction amount in the paper width direction is controlled based on the stiffness of the paper P and the paper width.

  FIG. 9 is an explanatory diagram showing the relationship between the first suction region R1 and the second suction region R2 and the openings 228a to 228e. In the control according to the present embodiment, suction is performed in the first suction region R1 corresponding to the center of the paper in the paper width direction, and air is blown toward the paper P in the second suction region R2 corresponding to both ends of the paper. . The distribution of the suction amount is adjusted through the setting mode of the first suction region R1 and the second suction region R2.

  Specifically, the central opening 228c is set as the first suction region R1. On the other hand, the two openings 228b and 228d located on both sides of the central opening 228c and the two openings 228a and 228e located at both ends are in accordance with the stiffness of the paper P and the paper width, and the first suction region R1. Alternatively, it is set as the second suction region R2. In this case, among the valve bodies 229a to 229e that control the amount of suction by the suction fan 227, the one corresponding to the first suction region R1 is set to the open state, and the one corresponding to the second suction region R2 is set to the closed state. The In addition, the valve body that controls the amount of air blown by the blower 260 is set to a closed state corresponding to the first suction region R1, and is set to an open state corresponding to the second suction region R2.

  First, a sheet P having a small sheet width is shown in FIG. The central opening 228c is set as the first suction region R1. On the other hand, the remaining openings 228a, 228b, 228d, 228e are set as the second suction region R2. That is, the distribution of the suction amount is such that the central opening 228c is in the suction state and the remaining openings 228a, 228b, 228d, and 228e are in the blowing state.

  FIG. 9B shows the paper P having a large paper width. The central opening 228c and the two adjacent openings 228b and 228d are set as the first suction region R1. On the other hand, the two openings 228a and 228e located at both ends are set as the second suction region R2. That is, in the distribution of the suction amount, the central opening 228c and the two adjacent openings 228b and 228d are in a suction state, and the remaining openings 228a and 228e are in a blowing state.

  As described above, regardless of the paper P of any paper width, suction is performed in the first suction region R1 corresponding to the center of the paper, and air is blown in the second suction region R2 corresponding to both ends of the paper. Therefore, when the paper P is attracted to the suction conveyance unit 220, the downward wind acts in the second suction region R2, and both ends of the paper hang down well. Due to the sagging of both ends of the sheet, a gap is formed between the uppermost sheet P and the second sheet P, and the separation air from the front fan section 230 is separated from the uppermost sheet P and the second sheet P. Can be sent in between. As a result, the separation of the paper P can be performed satisfactorily.

  For the paper P having a large paper width, the two openings 228b and 228d located on both sides of the central opening 228c are also set as the first suction region R1. That is, in the paper P having a large paper width, the range of the first suction region R1 is expanded toward the paper edge portion side compared to the paper P having a small paper width. The larger the paper width, the greater the influence of its own weight, so that the drooping of both ends of the paper becomes more prominent. Extreme drooping can be suppressed. Thereby, when the paper P is fed, the situation of interference with the guide member is suppressed, and the paper P can be fed appropriately.

  In addition, the setting of the first suction region R1 and the second suction region R2 differs depending on the rigidity even if the paper width is the same. Here, a description will be given by taking the paper P having a small paper width as an example.

  First, the paper P having a high stiffness is shown in FIG. 9A, similarly to the paper P having a small paper width. The central opening 228c is set as the first suction region R1. On the other hand, the remaining openings 228a, 228b, 228d, 228e are set as the second suction region R2. That is, the distribution of the suction amount is such that the central opening 228c is in the suction state and the remaining openings 228a, 228b, 228d, and 228e are in the blowing state.

  On the other hand, the paper P having a low stiffness is shown in FIG. The central opening 228c and the two adjacent openings 228b and 228d are set as the first suction region R1. On the other hand, the two openings 228a and 228e located at both ends are set as the second suction region R2. That is, in the distribution of the suction amount, the central opening 228c and the two adjacent openings 228b and 228d are in a suction state, and the remaining openings 228a and 228e are in a blowing state.

  In this way, suction is performed in the first suction region R1 corresponding to the center of the sheet and air is blown in the second suction region R2 corresponding to both ends of the sheet regardless of the stiffness. Therefore, when the sheet P is adsorbed to the suction conveyance unit 220, a downward wind acts in the second suction region R2, so that both ends of the sheet hang down satisfactorily. Due to the sagging of both ends of the sheet, a gap is formed between the uppermost sheet P and the second sheet P, and the separation air from the front fan section 230 is separated from the uppermost sheet P and the second sheet P. Can be sent in between. As a result, the separation of the paper P can be performed satisfactorily.

  For the paper P having a low stiffness, the two openings 228b and 228d located on both sides of the central opening 228c are also set as the first suction region R1. That is, in the paper P with a low stiffness, the range of the first suction region R1 is expanded toward the paper edge side compared to the paper P with a high stiffness. The lower the stiffness, the weaker the paper P, so that the drooping of both ends of the paper becomes more prominent. However, the range of the first suction region R1 is expanded and the range of the second suction region R2 is reduced, so that Extreme drooping can be suppressed. Thereby, when the paper P is fed, the situation of interference with the guide member is suppressed, and the paper P can be fed appropriately.

  In step S <b> 25, the control unit 250 starts blowing air from the blower 260 of the suction conveyance unit 220. In other words, the air blow by the blower 260 is executed after the paper P is adsorbed to the transport unit 221 and before the air blow of the front blower 230 is started.

  In step S <b> 29, the control unit 250 stops the driving of the transport unit 221 and stops the blowing of the tip blowing unit 230. Moreover, the control part 250 stops the ventilation of the air blower 260. FIG.

  As described above, in the large-capacity paper feeding device 200 according to the present embodiment, the blower 260 that blows air toward the paper P is connected to the suction conveyance unit 220. Then, the controller 250 sucks the paper P in the first suction region R1, and blows air toward the paper P in the second suction region R2.

  According to this configuration, since the downward wind acts in the second suction region R2 when the paper P is sucked, both ends of the paper hang down satisfactorily. Due to the sagging of both ends of the sheet, a gap is formed between the uppermost sheet P and the second sheet P, and the separation air from the front fan section 230 is separated from the uppermost sheet P and the second sheet P. Can be sent in between. As a result, the separation of the paper P can be performed satisfactorily.

  In the present embodiment, the control unit 250 blows air toward the paper P in the second suction region R2 after the uppermost paper P placed on the paper placement table 211 is adsorbed by the suction conveyance unit 220. Has started.

  According to this configuration, the air blowing in the direction opposite to the suction of the paper P is performed after the suction of the paper. Thereby, the suction of the paper P can be performed smoothly.

  Further, in the present embodiment, the control unit 250 starts air blowing toward the paper P in the second suction region R2 before the separation air is blown by the tip air blowing unit 230.

  According to this configuration, since air is started from the front blower 230 in a state where a gap is formed between the uppermost sheet P and the second sheet P, the separation air is supplied to the uppermost sheet P. And the second sheet P can be appropriately fed. Thereby, the separation of the paper P can be performed satisfactorily.

  In the present embodiment, the range of the first suction region R1 and the second suction region R2 is adjusted as control of the suction amount distribution according to the stiffness of the paper P and the paper width. However, the range of the first suction region R1 and the second suction region R2 may not be changed, and the size of the air blowing amount may be adjusted. For example, FIG. 10A is illustrated as a sheet P having a small sheet width, but the control unit 250 may decrease the air blowing amount in the second suction region R2 as the sheet width increases (FIG. 10B). It is. Further, FIG. 10A is illustrated as a sheet P having a high stiffness. However, the control unit 250 decreases the blowing amount of the second suction region R2 as the stiffness of the sheet P is small (FIG. 10C). That's right.

  In the present embodiment, it is assumed that the amount of air blown in the second suction region R2 is uniform in the paper transport direction. However, as shown in FIG. 11, the air flow rate in the second suction region R2 may be set such that the air flow rate on the paper rear end side is smaller than the air flow rate on the paper front end side. Thereby, the sagging of both ends of the paper can be appropriately realized without reducing the suction performance of the paper P.

  In the present embodiment, the shape of the suction surface of the suction conveyance unit 220 is set to a flat surface shape from both ends of the sheet. However, the suction conveyance unit 220 may have a convex shape such that the center of the sheet is larger than the both ends of the sheet with respect to the distance from the sheet P to the suction surface. Such a convex shape can be realized by changing the height at which the belt members 221a to 221e are arranged in the paper width direction, for example, as shown in FIG. As another method, as shown in FIGS. 12B and 12C, the distance between the belts of the belt members 221a to 221e may be changed in the paper width direction.

  According to this configuration, both ends of the sheet can be bent using the shape of the suction conveyance unit 220. In the case where the sheet P is bent using only the structure of the suction conveyance unit 220 without changing the distribution of the blowing amount, a large uneven shape must be set in the suction conveyance unit 220. However, by using together with the above-described suction amount distribution control, it is not necessary to provide a large uneven shape in the suction conveyance unit 220. Thereby, it is possible to suppress a situation in which the paper P is deformed due to the uneven shape of the suction conveyance unit 220.

  The image forming system according to the embodiment of the present invention has been described above, but the present invention is not limited to the above-described embodiment, and it is needless to say that various modifications are possible within the scope of the invention. . Further, not only the image forming system but also a sheet feeding device (large capacity sheet feeding device) constituting the image forming system itself functions as a part of the present invention. Further, the present invention may be applied to a paper feed unit built in the image forming apparatus, and in this case, the image forming apparatus can also function as a part of the present invention.

  When the image forming system includes an image forming apparatus and a paper feeding device, the image forming apparatus and the paper feeding device may each have a control function, or one control function may be integrated. The structure provided with a control function may be sufficient. Whether it is an individual control function or a single control function, it functions as a control unit that controls the image forming apparatus and the sheet feeding apparatus.

  In the present embodiment, the suction conveyance unit has a configuration in which the number of belt members and openings correspond to each other, but the present invention is not limited to this. For example, one common opening may be set for a plurality of belt members, or a plurality of openings may be set within the width of one belt member having a large width. .

  Moreover, although the valve body was used as a technique for switching the distribution of the suction amount, any technique that can block the internal flow path can be widely applied.

  Further, the first suction area and the second suction area are set by opening and closing the opening, but the opening width of the opening is adjusted using an adjustment mechanism such as a shutter to The setting with the second suction area may be performed.

DESCRIPTION OF SYMBOLS 100 Image forming apparatus 10Y, 10M, 10C, 10K Image forming part 11Y, 11M, 11C, 11K Photosensitive drum 15 Intermediate transfer belt 16 Secondary transfer roller 20 Paper conveyance part 40 Fixing apparatus 50 Control part 200 Large capacity paper feeder ( Paper feeder)
DESCRIPTION OF SYMBOLS 201 Conveyance roller 210 Paper feed unit 211 Paper mounting base 220 Suction conveyance part 221 Conveyance part 221a, 221b, 221c, 221d, 221e Belt member 223a, 223b, 223c, 223d, 223e Drive roller 224a, 224b, 224c, 224d, 224e Roller 225a, 225b, 225c, 225d, 225e Driven roller 226 Suction part 227 Suction fan 228 Duct 228a, 228b, 228c, 228d, 228e Opening part 229a, 229b, 229c, 229d, 229e Valve body 230 Front end blowing part 240 Side end blowing Unit 250 control unit 251 paper suction sensor 252 paper detection sensor 260 blower R1 first suction region R2 second suction region

Claims (14)

In a paper feeding device that feeds paper from a paper placement table on which a bundle of paper is placed,
A suction conveying unit that sucks and conveys the uppermost sheet among the bundle of sheets placed on the sheet placing table;
A control unit for controlling the suction conveyance unit,
The suction conveyance unit includes a suction region that sucks a sheet in a sheet width direction orthogonal to the sheet conveyance direction;
The control unit is a paper feeding device that controls the distribution of the suction amount in the paper width direction based on the stiffness of the paper and the paper width that is the paper size in the paper width direction. The control unit controls the distribution of the suction amount in the paper width direction so that the suction amount in the second suction region corresponding to both ends of the paper is smaller than the suction amount in the first suction region corresponding to the center of the paper. 1. The sheet feeding device according to claim 2, wherein the control unit does not perform suction in the second suction region. The suction conveyance unit is connected to a blowing unit that blows air toward the paper,
4. The sheet feeding device according to claim 2, wherein the control unit sucks a sheet in the first suction area and blows air toward the sheet in the second suction area. 5. The sheet feeding device according to claim 4, wherein the control unit starts blowing air in the second suction area after the uppermost sheet is adsorbed by the suction conveyance unit. It further has a tip blower that blows air from the leading edge side of the paper in the paper transport direction to the paper bundle,
The sheet feeding device according to claim 5, wherein the control unit starts blowing the second suction area before starting blowing by the tip blowing unit. The sheet feeding device according to any one of claims 4 to 6, wherein the control unit reduces the blowing amount of the second suction area as the stiffness of the sheet is smaller. The sheet feeding device according to any one of claims 4 to 7, wherein the control unit decreases the blowing amount of the second suction area as the sheet width increases. The paper feeding device according to any one of claims 4 to 8, wherein the air blowing amount in the second suction area is set such that the air blowing amount on the paper rear end side in the paper transport direction is smaller than the air blowing amount on the paper front end side. The paper feeding device according to any one of claims 2 to 9, wherein the control unit expands the range of the first suction area toward both ends of the paper as the stiffness of the paper is small. 11. The sheet feeding device according to claim 2, wherein the control unit expands the range of the first suction area toward both ends of the sheet as the sheet width increases. The sheet feeding device according to claim 1, wherein the suction conveyance unit has a convex shape such that a center of the sheet is larger than both ends of the sheet with respect to a distance to the uppermost sheet. In a paper feeding device that feeds paper from a paper placement table on which a bundle of paper is placed,
A suction conveying unit that sucks and conveys the uppermost sheet among the bundle of sheets placed on the sheet placing table;
A control unit for controlling the suction conveyance unit,
The suction conveyance unit includes a suction region that sucks a sheet in a sheet width direction orthogonal to the sheet conveyance direction;
The control unit controls the distribution of the suction amount in the sheet width direction so that the suction amount in the second suction area corresponding to both ends of the sheet is smaller than the suction amount in the first suction area corresponding to the center of the sheet. apparatus. A paper feeding device for feeding paper from a paper placement table on which a bundle of paper is placed;
An image forming apparatus for forming an image on a sheet fed from the sheet feeding apparatus;
A control unit that controls the sheet feeding device and the image forming apparatus,
The paper feeder is
A suction conveyance unit that sucks and conveys the uppermost sheet of the bundle of sheets placed on the sheet placement table;
The suction conveyance unit includes a suction region that sucks a sheet in a sheet width direction orthogonal to the sheet conveyance direction;
The control unit is an image forming system that controls the distribution of the suction amount in the paper width direction based on the stiffness of the paper and the paper width that is the paper size in the paper width direction.

Images