JP2018131302A - Paper feeder and image formation system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a paper feeder capable of satisfactorily sucking and conveying a sheet placed on a sheet loading table.SOLUTION: A sucking and conveying part 220 comprises a first sucking and conveying part in which a distance to a sheet P placed on a sheet loading table 211 is set to a first distance D1, and a second sucking and conveying part in which a distance to the sheet P placed on the sheet loading table 211 is set to a second distance D2 shorter than the first distance D1. The first sucking and conveying part and the second sucking and conveying part are arranged in parallel to the sheet conveying direction. The first sucking and conveying part sucks the edge area the sheet P in the sheet width direction, and the second sucking and conveying part sucks the central area of the sheet P in the sheet width direction rather than the first sucking and conveying part. In this case, a control part controls the first sucking and conveying part and the second sucking and conveying part by their separate suction amounts.SELECTED DRAWING: Figure 4

Description

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

  In recent years, there has been known an image forming system capable of performing various processes including image formation in series. This image forming system is configured by arranging at least one device 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 and a post-processing apparatus that performs post-processing on a sheet, a sheet feeding unit that holds a large volume of paper and feeds it to the image forming apparatus Apparatus.

  The paper feeding device includes one or more paper feeding units that feed paper, and the paper fed from the paper feeding unit is transported along a transport path and discharged outside the apparatus. Accordingly, the sheet can be supplied to an apparatus connected downstream, for example, an image forming apparatus. Each paper feed unit is provided with a paper placement table. A paper bundle made up of a plurality of papers is placed on the paper placement table, and the paper located on the uppermost surface of the paper bundle is fed one by one.

  For example, Patent Document 1 discloses a paper feeding device that conveys a sheet positioned on the uppermost surface placed on a sheet placing table by adsorbing the sheet to the surface of a conveying unit. The conveying portion has a stepped shape that is stretched so that end portions corresponding to both sides of the belt protrude from the center of the belt in a cross section orthogonal to the sheet conveying direction.

  On the other hand, for example, Patent Document 2 discloses a paper feeding device that sucks and conveys a sheet loaded on a sheet placing table to a conveyance unit. In this sheet feeding device, the effective suction area is distributed so as to be smaller at both ends than in the center of the transport unit in a direction orthogonal to the sheet transport direction.

JP2011-225290A JP 2013-166541 A

  However, in the conventional transport mode, for example, a stiff sheet such as cardboard may not follow the stepped shape of the transport unit. Thereby, there is a possibility that poor conveyance such as double feeding cannot be improved.

  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 satisfactorily adsorb and convey the paper stacked on the paper mounting table.

  In order to solve such a problem, the first invention sucks the paper placed on the paper placing table in a paper feeding device that feeds the paper from the paper placing table on which one or more sheets are placed. And a control unit that controls the suction amount of the suction transport unit. In the sheet feeding device, the suction conveyance unit includes a distance between the first suction conveyance unit in which the distance to the paper placed on the paper placement table is set to the first distance and the paper placed on the paper placement table. And a second suction conveyance unit set at a second distance smaller than the first distance, and the first suction conveyance unit and the second suction conveyance unit are arranged in parallel with the paper conveyance direction, and the first suction conveyance unit Sucks the edge region of the paper in the paper width direction, and the second suction conveyance unit sucks the central region of the paper in the paper width direction more than the first suction conveyance unit. Then, the control unit controls the first suction conveyance unit and the second suction conveyance unit with independent suction amounts.

  Here, in the first invention, when the control unit determines that the sheet is attracted to the second suction conveyance unit after the suction by the suction conveyance unit is started, the suction amount of the first suction conveyance unit is set to the second suction amount. It is preferable to perform control so as to be larger than the suction amount of the suction conveyance unit.

  In the first aspect of the invention, the control unit may determine that the suction amount of the first suction conveyance unit is greater than the suction amount of the second suction conveyance unit when a predetermined time has elapsed after the suction by the suction conveyance unit has started. It is preferable to perform control that increases.

  In the first aspect of the invention, the control unit preferably performs control so that the suction amount of the first suction conveyance unit is larger than the suction amount of the second suction conveyance unit simultaneously with the start of suction by the suction conveyance unit. .

  In the first invention, the control unit preferably performs control such that the first suction amount is larger than the second suction amount when the job satisfies a preset condition.

  In this case, the condition preferably includes one or more of the basis weight of the paper, the thickness of the paper, and the rigidity of the paper. Alternatively, it is preferable that the condition is an environment recognized by the image forming apparatus which is a paper basis weight specified by the user or a paper feed destination.

  In addition, the first invention may further include a suction detection unit that is provided in each of the first suction transport unit and the second suction transport unit and detects the suction of the paper. In this case, the control unit determines that the sheet is attracted to the second suction conveyance unit after starting the suction by the suction conveyance unit, and determines that the sheet is not attracted to the first suction conveyance unit within a predetermined time. In this case, it is preferable to perform control so that the suction amount of the first suction conveyance unit is larger than the suction amount of the second suction conveyance unit.

  In addition, the first invention may further include a side-end air blowing unit that blows air on a side end parallel to the sheet conveyance direction in the sheet bundle placed on the sheet placing table. In this case, when the control unit determines that the sheet is attracted to the first suction conveyance unit, the control unit preferably switches the wind direction of the side end blowing unit from the direction parallel to the sheet surface to the upward direction.

  In addition, the first invention may further include a front-end air blowing unit that blows air to a front-end portion parallel to the paper width direction in the sheet bundle placed on the paper placement table. In this case, when the control unit determines that the sheet is attracted to the first suction conveyance unit, the control unit preferably switches the wind direction of the front blowing unit from the direction parallel to the sheet surface to the upward direction.

  Further, in the first invention, the suction conveyance unit is divided corresponding to one suction fan, the first suction conveyance unit and the second suction conveyance unit, and each of the ducts includes an opened opening, It is preferable to include a shutter member that blocks a passage in the duct corresponding to the two suction conveyance unit or adjusts an area of a variable opening set in the passage in the duct.

  In the first aspect of the invention, it is preferable that the opening corresponding to the first suction conveyance unit is disposed on the downstream side in the paper conveyance direction with respect to the opening corresponding to the second suction conveyance unit.

  In the first invention, the control unit sucks and conveys a predetermined number of sheets after the start of the job, and the suction amount of the first suction conveyance unit is larger than the suction amount of the second suction conveyance unit. When it is determined whether or not to perform such control, and when it is determined that the control is performed, the suction amount of the first suction transport unit is set to the second suction transport unit when sucking and transporting subsequent sheets. It is preferable to apply a control that is larger than the suction amount.

  Further, the second invention is an image forming system comprising the paper feeding device according to the first invention and an image forming device for forming an image on a paper fed from the paper feeding device. provide.

  According to the present invention, it is possible to provide a paper feeding device and an image forming system capable of properly adsorbing and appropriately transporting papers stacked on a paper mounting table.

1 is a front view schematically showing the configuration of an image forming system according to an embodiment. Front view schematically showing the configuration of the paper feed unit Top view showing the configuration of the suction transfer unit Explanatory drawing which shows the structure of a suction conveyance part from the downstream of a paper conveyance direction Flow chart showing the operation procedure of the large capacity paper feeder Explanatory drawing showing the suction state of the paper

  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 supplied 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, and a fixing device 40, and these elements are accommodated in one casing. ing.

  The document reader SC scans and exposes an image of the document with the optical system of the scanning exposure device, reads the reflected light with a 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 apparatus 100 or another image forming apparatus, 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. Further, 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 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 composed of each color transferred onto the intermediate transfer belt 15 is transferred by the secondary transfer roller 16 onto the paper P that is transported at a predetermined timing by a paper transport unit 20 described later. 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 feed unit 21 or the paper P supplied from the large-capacity paper feeder 200 according to a series of transport paths.

  The fixing device 40 is a device that performs a fixing process on the paper P onto which the image has been transferred, that is, the paper P sent out from the transfer nip. 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 members. The fixing device 40 fixes the transferred image onto the paper P through the action of the pressure by the pair of fixing rollers and the heat of the fixing roller as the paper P passes through the fixing nip. The paper P subjected to the fixing process by the fixing device 40 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 sheet P with the front and back 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 other surface.

  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 job setting conditions (information on paper P (basis weight, etc.), image density and magnification, and information on a paper feed unit serving as a paper feed source) 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 paper feeding device for feeding paper P to the image forming apparatus 100, and is disposed on the upstream side of the image forming apparatus 100. 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 supply unit 210 stores one or more sheets P and supplies the stored sheets P one by one. 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 supply unit 210, a plurality of stacked sheets of paper P (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, the sheet placing table 211 is configured to be able to be pulled out from the large capacity sheet feeding device 200 by the guide rail 214.

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

  The trailing edge regulating member 213 regulates the trailing edge position of the sheet bundle on the sheet placing table 211 and is supported by the main body of the large capacity sheet feeding device 200 so as to be displaceable in the sheet conveying direction.

  The rear end regulating member 213 is provided with a height sensor (not shown) that detects the height of the bundle of sheets stacked on the sheet placing table 211. The control unit 250 drives the lifting mechanism based on the signal from the height sensor and performs control to raise and lower the paper placement table 211. By this control, the uppermost sheet P of the sheet bundle stacked on the sheet placing table 211 is maintained at a constant height.

  The suction conveyance unit 220 is disposed above the sheet placement table 211 so as to face the sheet placement table 211, and sucks the uppermost sheet P of the sheet bundle placed on the sheet placement table 211. It is to be transported.

  The suction conveyance unit 220 is mainly composed of a conveyance unit 221 and a suction unit 226. FIG. 3 is a top view illustrating the configuration of the suction conveyance unit 220. FIG. 4 is an explanatory diagram illustrating a configuration of the suction conveyance unit 220, and is a schematic diagram illustrating a cross-sectional state of the suction conveyance unit 220 viewed from the downstream side in the paper conveyance direction.

  The transport unit 221 transports the paper P, and includes a plurality of endless belt members. In the present embodiment, the transport unit 221 includes four belt members 221a to 221d arranged in parallel with the paper transport direction, and each belt member 221a to 221d is in the paper width direction (perpendicular to the paper transport direction). (Direction).

  The individual belt members 221a to 221d are stretched around large-diameter driving rollers 223a to 223d connected to the driving source 222 and two driven rollers 224a to 224d and 225a to 225d. The driving rollers 223a to 223d are disposed on the upstream side in the paper transport direction, and the two driven rollers 224a to 224d and 225a to 225d are disposed on the downstream side in the paper transport direction and spaced apart from each other.

  The individual belt members 221a to 221d rotate when the driving rollers 223a to 223d are driven to rotate, and the surface facing the paper P moves in the paper transport direction. The drive rollers 223a to 223d are rotationally driven in synchronization, and the individual belt members 221a to 221d are also rotated in synchronization. Each belt member 221a-221d is provided with a plurality of through holes (not shown) each having a small diameter.

  In the present embodiment, the lower driven rollers 225b and 225c corresponding to the central belt members 221b and 221c are offset below the lower driven rollers 225a and 225d corresponding to the belt members 221a and 221d on both sides. Placed in position. Due to this arrangement relationship, the belt members 221a and 221d on both sides are arranged relatively above the central belt members 221b and 221c. As a result, the distance between the belt members 221a and 221d at both ends and the paper P becomes the first distance D1, while the distance between the central belt members 221b and 221c and the paper P is greater than the first distance D1. Is also a small second distance D2.

  The suction unit 226 is disposed so as to face the paper P across the transport unit 221. In the present embodiment, the suction unit 226 is disposed inside the belt members 221 a to 221 d that are the transport unit 221. The suction unit 226 sucks air through the transport unit 221 and causes the belt members 221a to 221d to suck the paper P (the paper P positioned on the uppermost surface of the paper bundle) placed on the paper placement table 211.

  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 that guides air from the transport unit 221 to the suction fan 227. The duct 228 is divided into two duct portions 228a and 228b, each serving as a passage, corresponding to the belt members 221b and 221c at the center and the belt members 221a and 221d on both sides. Specifically, a partition wall 228c is provided inside the duct 228 along the air flow direction, and two duct portions 228a and 228b are formed with the partition wall 228c interposed therebetween. However, the configuration of the duct 228 may utilize two ducts that are divided in advance, in addition to dividing the inside of a single duct.

  Of the two duct portions 228a and 228b, the duct portion 228a on the downstream side in the paper transport direction is a duct portion corresponding to the belt members 221a and 221d on both sides. The duct portion 228a is provided with openings 228a1 and 228a2 that are opened to face the belt members 221a and 221d. On the other hand, the upstream duct portion 228b in the paper conveyance direction is a duct portion corresponding to the central belt members 221b and 221c. The duct portion 228b is provided with openings 228b1 and 228b2 that are opened to face the belt members 221b and 221c. The openings 228a1 and 228a2 corresponding to the belt members 221a and 221d on both sides are arranged downstream of the openings 228b1 and 228b2 corresponding to the central belt members 221b and 221c in the paper transport direction.

  In the duct portion 228b corresponding to the central belt members 221b and 221c, a shutter member 229 for blocking the duct passage is provided between the suction fan 227 and the openings 228b1 and 228b2. The shutter member 229 is movable by a driving mechanism (not shown), and can be switched between a blocking position for blocking the duct internal passage and an open position for opening the duct internal passage. The operation of the shutter member 229 is controlled by the control unit 250.

  In the suction conveyance unit 220, air is sucked by the suction unit 226, the uppermost sheet P of the sheet bundle is attracted to the conveyance unit 221, and the conveyance unit 221 is rotated to send the sheet P to the conveyance path. be able to. That is, the transport unit 221 functions as a suction transport unit that sucks and transports the paper P placed on the paper placement table 211 by cooperating with the suction unit 226. In this case, the belt members 221a and 221d and the suction unit 226 on both sides correspond to the first suction conveyance unit in which the distance from the paper P is set to the first distance D1, and the end of the paper P in the paper width direction Aspirate the area. On the other hand, the central belt members 221b and 221c and the suction unit 226 correspond to a second suction conveyance unit in which the distance from the paper P is set to the second distance D2, and the belt members 221a and 221d on the both sides. Rather, the area including the center of the paper P is sucked. Thus, the suction conveyance unit 220 of the present embodiment is set to have a step shape with different heights at the center and both sides thereof.

  Please refer to FIG. 1 and FIG. 2 again. The front air blowing unit 230 is disposed in front of the paper placement table 211 and in the vicinity of the suction conveyance unit 220, and has a function of blowing air to the front end portion parallel to the paper width direction in the sheet bundle placed on the paper placement table 211. Is responsible. The tip blower 230 is configured mainly with a blower 231 and a blower opening 232.

  The blower 231 outputs a wind for floating the uppermost sheet P of the sheet bundle or scooping the uppermost sheet P from the lower sheet P. For example, a multi-blade fan (sirocco) Fan) can be used. The air outlet 232 is a duct for blowing the wind output from the blower 231 toward the sheet bundle. The air outlet 232 is provided with a louver 233 that switches the direction of the output wind. With this louver 233, the direction of the wind blown out from the air blowing port 232 can be switched between a direction parallel to the sheet surface and an upward direction.

  The side edge blower 240 is disposed on the side of the paper placement table 211 and has a function of blowing air to the side edge parallel to the paper conveyance direction in the sheet bundle placed on the paper placement table 211. Yes. 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. Note that the side-end air blowing unit 240 may be provided only on one side of the sheet bundle.

  The blower 241 outputs a wind for floating the uppermost sheet P in the sheet bundle or scooping the uppermost sheet P from the lower sheet P. For example, a multi-blade fan (sirocco) Fan) can be used. The air outlet 242 is a duct for blowing the wind output from the blower 241 toward the sheet bundle. The air outlet 242 is provided with a louver 243 that switches the direction of the output wind. With this louver, the direction of the wind blown from the blower opening 242 can be switched between a direction parallel to the sheet surface and an upward direction.

  The paper feeding operation related to the paper P in the paper feeding unit 210 having such a configuration will be described. First, the direction of the wind output from the front blower 230 and the side blower 240 is set in a direction parallel to the paper surface. By outputting wind from these air blowing units 230 and 240, several sheets P are lifted against the weight of the sheet P from the uppermost surface of the sheet stack placed on the sheet placing table 211. In addition, the uppermost sheet P is adsorbed to the transport unit 221 by the suction of air by the suction unit 226. The details of the sheet P suction operation by the transport unit 221 will be described later.

  When the paper P is adsorbed to the transport unit 221, the direction of the wind of the leading end blowing unit 230 and the side end blowing unit 240 is changed upward. Thus, wind flows between the uppermost sheet P and the lower sheet P (second sheet P from the top), and the uppermost sheet P is separated from the lower sheet P. As a result, only the uppermost sheet P of the sheet bundle is conveyed by the conveying unit 221. The paper P fed from the suction transport unit 220 is transported by transport rollers arranged along the transport path and is discharged outside the apparatus. Then, the paper P is supplied to the image forming apparatus 100 which is an apparatus connected downstream.

  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.

  In relation to the present embodiment, the control unit 250 includes a first suction amount that is the suction amount of the belt members 221a and 221d on both sides that is the first suction conveyance unit, and a central belt member 221b that is the second suction conveyance unit. , 221c and the second suction amount are independently controlled. Through such independent control, the control unit 250 can appropriately follow the sheet P with respect to the suction conveyance unit 220 having a step shape that differs in height between the center and both sides thereof.

  Specifically, when the suction unit 226 is operated to start suction, the control unit 250 performs control such that the first suction amount becomes larger than the second suction amount with the first transition condition as a trigger. Moreover, the control part 250 switches the direction of the wind output from the front air blower 230 and the side end air blower 240 by using the second transition condition as a trigger. Then, the control unit 250 rotates the transport unit 221 to transport the paper P.

  Detection signals from various sensors are input to the control unit 250. As shown in FIG. 3, the paper suction sensor 251a is provided corresponding to the belt members 221b and 221c at the center, and is a sensor that detects the suction of the paper P to the belt members 221b and 221c. On the other hand, the paper suction sensor 251b is provided corresponding to the belt members 221a and 221d on both sides, and is a sensor that detects the suction of the paper P to the belt members 221a and 221d.

  Hereinafter, the operation of the large-capacity paper feeding device 200 of the image forming system according to the present embodiment will be described. Here, FIG. 5 is a flowchart showing an operation procedure of the large-capacity paper feeding device 200. The process shown in this flowchart shows the operation of the suction conveyance unit 220 related to the feeding of one sheet of paper, and is executed for each sheet of paper by the control unit 250 when called by a job input as a trigger. FIG. 6 is an explanatory diagram schematically showing the transition of the suction state of the paper P.

  First, in step 1 (S1), the control unit 250 determines whether or not the job satisfies a predetermined condition. This condition is that the basis weight of the paper P to be fed in the job is not less than a specified value. This specified value is a parameter for separating the stiff paper P (thin paper, etc.) and the stiff paper P (thick paper, etc.), and an optimal value is set in advance through experiments and simulations. The control unit 250 can make the determination in step 1 by grasping the basis weight of the paper P from the setting conditions designated by the user when executing the job.

  If an affirmative determination is made in step 1, that is, if the job meets the condition, the process proceeds to step 2 (S2). On the other hand, if a negative determination is made in step 1, that is, if the job does not meet the condition, the process proceeds to step 9 (S9) described later.

  If the paper P is weak, following the step shape of the suction conveyance unit 220 may cause wrinkles or creases. The conditions in step 1 are for determining whether wrinkles or creases occur on the paper P by following the step shape of the suction conveyance unit 220. Therefore, if such a state can be determined, in addition to the basis weight of the paper P, conditions such as the thickness of the paper P or the rigidity of the paper P may be used. These conditions can be acquired from the setting conditions specified by the user when executing the job.

  Further, in a situation where the amount of moisture contained in the air is large, the paper P tends to become weak, so the environment such as humidity and temperature alone, or the basis weight of the paper P, the thickness of the paper P, or the paper The above conditions may be combined with the rigidity of P. As information related to the environment, information detected by a temperature sensor and a humidity sensor included in the image forming apparatus 100 can be acquired from the image forming apparatus 100 that is the paper feed destination of the paper P.

  In Step 2, the control unit 250 starts the suction by operating the suction unit 226. At the timing of starting suction, the control unit 250 controls the shutter member 229 to the open position. Therefore, air is sucked from the openings 228a1 to 228b2 corresponding to the belt members 221a to 221d, respectively. In the case of the configuration of the present embodiment, at the start of suction, the first suction amount corresponding to the center and the second suction amount corresponding to both sides are the same.

  Further, in Step 2, the control unit 250 operates the leading end blowing unit 230 and the side end blowing unit 240 to output wind to the sheet end surfaces (the leading end surface and the side end surfaces), and causes the sheet P to float. In this case, the direction of the wind output from the front end blowing unit 230 and the side end blowing unit 240 is set in a direction parallel to the sheet surface.

  In step 3 (S3), control unit 250 determines whether or not the first transition condition is satisfied. Since the stiff paper P floats in a substantially flat state, it is attracted to the central belt members 221b and 221c that are close to the paper P (FIG. 6A). The controller 250 determines that the sheet P is attracted to the central belt members 221b and 221c as the first transition condition. This determination is made based on the detection result of the paper suction sensor 251a.

  If the first transition condition is satisfied, that is, if the paper P is attracted to the central belt members 221b and 221c, an affirmative determination is made in step 3 and the process proceeds to step 4 (S4). On the other hand, if the first transition condition is not satisfied, that is, if the sheet P is not attracted to the central belt members 221b and 221c, a negative determination is made and the routine returns to step 3.

  However, the first transition condition does not require strict determination of the timing at which the paper P is attracted to the belt members 221b and 221c. For this reason, the first transition condition may be that a predetermined time has elapsed since it is considered that the sheet P is adsorbed to the belt members 221b and 221c from the start of suction. At this predetermined time, an optimum value can be set in advance through experiments and simulations. The first transition condition is that the sheet P is adsorbed to the central belt members 221b and 221c, and the sheet P is not adsorbed to the belt members 221a and 221d at both ends within a certain time from the adsorption of the sheet P. It is good.

  In step 4, the control unit 250 decreases the second suction amount corresponding to the center. Specifically, the control unit 250 moves the shutter member 229 to the blocking position and blocks the duct unit 228b. Therefore, the air sucked from the openings 228b1 and 228b2 provided in the duct portion 228b is stopped, and the second suction amount becomes zero. As a result, the first suction amount corresponding to both sides becomes larger than the second suction amount corresponding to the center.

  In addition, in this embodiment, the two duct portions 228a and 228b share the suction fan 227. Therefore, the air sucked by the suction fan 227 is concentrated on the remaining duct portion 228a by the operation of the shutter member 229, and compared with the control state before step 4, the openings 228a1 and 228a2 provided in the duct portion 228a. Suction volume increases. For this reason, the 1st amount of suction corresponding to both sides will be in a state larger than the state before performing control of Step 4.

  As described above, the control in step 4 corresponds to a control in which the first suction amount corresponding to both sides is larger than the second suction amount corresponding to the center. As the first suction amount relatively increases, the suction force acting on both ends of the paper P increases. As a result, both ends of the paper P are lifted (see FIG. 6B).

  In step 5 (S5), the control unit 250 determines whether or not the second transition condition is satisfied. The second transition condition is that the paper P is attracted to the belt members 221a and 221d on both sides. This determination is made based on the detection result of the paper suction sensor 251b.

  When the second transition condition is satisfied, that is, when the paper P is adsorbed to the belt members 221a and 221b on both sides, an affirmative determination is made in step 5, and the process proceeds to step 6 (S6). On the other hand, if the second transition condition is not satisfied, that is, if the sheet P is not attracted to the belt members 221a and 221d on both sides, a negative determination is made and the process returns to step 5.

  However, the second transition condition does not require strict determination of the timing at which the paper P is attracted to the belt members 221a and 221d on both sides. For this reason, the second transition condition may be that the time when it can be considered that the paper P is adsorbed to the belt members 221a and 221d on both sides from the start of the control in Step 4 may be passed. For this elapsed time, an optimum value can be set in advance through experiments and simulations.

  In step 6, the control unit 250 increases the second suction amount corresponding to the center. Specifically, the control unit 250 moves the shutter member 229 to the open position and opens the duct unit 228b. Thereby, air is sucked from the openings 228b1 and 228b2 provided in the duct part 228b. This suction of air causes the paper P to be adsorbed to the central belt members 221b and 221c (see FIG. 6C).

  In step 7 (S7), the control unit 250 switches the direction of the wind output from the leading end blowing unit 230 and the side end blowing unit 240 from a direction parallel to the sheet surface to the upward direction. By the switching of the wind direction, the wind output from the front blower 230 and the side blower 240 is effectively between the uppermost sheet P in which both ends are lifted and the sheet P underneath. enter in. As a result, the sheet P positioned below the uppermost sheet P is spread, and the second sheet P can be separated from the uppermost sheet P (see FIG. 6C).

  In Step 8 (S8), the control unit 250 rotates and drives the driving rollers 223a to 223d to rotate the individual belt members 221a to 221d, thereby starting the conveyance of the paper P.

  On the other hand, in step 9, the control unit 250 starts the suction by operating the suction unit 226. At the start of suction, the control unit 250 controls the shutter member 229 to the open position. Therefore, air is sucked from the openings 228a1 to 228b2 corresponding to the belt members 221a to 221d, respectively. In the case of the configuration of the present embodiment, at the start of suction, the first suction amount corresponding to the center and the second suction amount corresponding to both sides are the same. And after performing the process of this step 9, it progresses to step 7 mentioned above.

  The control unit 250 performs such a series of processes for each sheet, and sequentially feeds the sheets P placed on the sheet placing table 211.

  As described above, the large-capacity paper feeding device 200 according to the present embodiment is a paper feeding device that feeds the paper P from the paper placing table 211 on which one or more sheets P are placed, and is placed on the paper placing table 211. A suction conveyance unit 220 that sucks and conveys the placed paper P and a control unit 250 that controls a suction amount of the suction conveyance unit 220 are provided. Here, the suction conveyance unit 220 includes the first suction conveyance unit in which the distance to the paper P placed on the paper placement table 211 is set to the first distance D1, and the paper P placed on the paper placement table 211. And a second suction conveyance unit set to a second distance D2 that is smaller than the first distance D1, and the first suction conveyance unit and the second suction conveyance unit are arranged in parallel with the paper conveyance direction. Then, the first suction conveyance unit sucks the end region in the paper width direction of the paper P, and the second suction conveyance unit sucks the central region in the paper width direction of the paper P more than the first suction conveyance unit. In this case, the control unit 250 controls the first suction conveyance unit and the second suction conveyance unit with independent suction amounts.

  According to this configuration, the suction conveyance unit 220 includes the first suction conveyance unit that faces the end region of the paper P, and the second suction conveyance unit that sucks the central region of the paper P more than the first suction conveyance unit. It becomes a stepped shape. Further, since the suction amount (first suction amount) of the first suction transport unit and the suction amount (second suction amount) of the second suction transport unit can be controlled independently, the suction of the paper P is the first. It can be performed by separating the first suction conveyance unit and the second suction conveyance unit. Thereby, the paper P can be made to follow appropriately with respect to the level | step difference shape of the suction conveyance part 220. FIG. For this reason, since the paper P can be deformed so that the end region in the paper width direction is lifted, a wind for spreading the paper P is sent to the gap between the uppermost paper P and the lower paper P. it can. As a result, the sheets P can be appropriately separated from each other, and the occurrence of double feeding can be suppressed. Therefore, the paper P stacked on the paper placement table 211 can be satisfactorily attracted and appropriately conveyed.

  In this embodiment, the suction conveyance unit 220 includes a pair of first suction conveyance units disposed on both sides, and a second suction conveyance unit sandwiched between the first suction conveyance units. . In this case, the pair of first suction conveyance units includes the belt members 221 a and 221 d and the suction unit 226 on both sides, and the second suction conveyance unit includes the central belt members 221 b and 221 c and the suction unit 226.

  According to this configuration, the suction conveyance unit 220 is configured in a stepped shape in which the center is convex downward in the sheet width direction. For this reason, a gap can be generated between the uppermost sheet P and the lower sheet P in both end regions in the sheet width direction. For this reason, the air flows between the uppermost sheet P and the lower sheet P from the gaps on both sides, so that the two can be effectively separated.

  In the present embodiment, the controller 250 determines that the sheet P is adsorbed to the second suction conveyance unit after the suction conveyance unit 220 starts the suction, and then the first suction amount is greater than the second suction amount. Control is performed to increase.

  According to this configuration, the suction force of the first suction conveyance unit that sucks the edge region of the paper P is relatively increased. Due to the increase in the suction force, the paper P can appropriately follow the stepped shape of the suction conveyance unit 220, so that the paper P can be deformed so that the end region is lifted (FIG. 6B). reference). As a result, a gap can be formed between the uppermost sheet P and the next sheet P in the end region in the sheet width direction. The air flows between the uppermost sheet P and the next sheet P from the gap, so that the two can be effectively separated.

  In the present embodiment, the control unit 250 determines the suction of the paper P based on the paper suction sensors 251a and 251b. However, the control unit 250 may determine that the paper P is attracted to the transport unit 221 based on a predetermined time passage. In addition, when the controller 250 determines that the sheet P is attracted to the second suction conveyance unit and determines that the sheet P is not attracted to the first suction conveyance unit within a predetermined time, the first suction amount is Control may be performed so as to be larger than the second suction amount. As described above, the first transition condition shown in Step 3 can be variously modified.

  In this embodiment, after the sheet P is sucked by the second suction conveyance unit, control is performed so that the first suction amount becomes larger than the second suction amount. At the same time, control may be performed so that the first suction amount becomes larger than the second suction amount.

  Further, in the present embodiment, the sheet bundle placed on the sheet placing table 211 further includes a side end blower 240 that blows air to a side end parallel to the sheet conveyance direction. In this case, when the control unit 250 determines that the sheet P is attracted to the first suction conveyance unit, the control unit 250 switches the wind direction of the side end air blowing unit 240 from the direction parallel to the sheet surface to the upward direction.

  According to this configuration, the wind direction of the side edge blower 240 is changed from the direction for floating the paper P (the direction parallel to the paper surface) to the direction from the uppermost paper P to the paper P below it ( (Upward direction). As a result, the wind output from the side edge blower 240 effectively flows into the gap between the uppermost sheet P and the next sheet P. As a result, the air flows between the uppermost sheet P and the next sheet P, so that the two can be effectively separated.

  Furthermore, in this embodiment, the front end blowing unit 230 that blows air to the front end portion parallel to the paper width direction in the paper stack placed on the paper placement table 211 is further provided. In this case, when the control unit 250 determines that the sheet P is adsorbed to the first suction conveyance unit, the control unit 250 switches the wind direction of the front blower unit 230 from the direction parallel to the sheet surface to the upward direction.

  According to this configuration, the wind direction of the front blower 230 is changed from the direction for floating the paper P (the direction parallel to the paper surface) to the direction from the uppermost paper P to the lower paper P (upward). Direction). As a result, the wind output from the front blower 230 effectively flows into the gap between the uppermost sheet P and the next sheet P. As a result, the air flows between the uppermost sheet P and the next sheet P, so that the two can be effectively separated.

  In the present embodiment, the wind direction is changed for both the front-end blower 230 and the side-end blower 240. However, the direction of the wind may be changed for either one of the front end blowing unit 230 and the side end blowing unit 240. In this case, a control mode may be determined according to the type of the paper P, such as whether to change the wind direction of only one of the front end blowing unit 230 and the side end blowing unit 240, or whether to change both wind directions. Further, the timing for changing the wind direction of the front end blowing unit 230 and the side end blowing unit 240 may be changed according to the type of the paper P.

  In the present embodiment, the control unit 250 performs control such that the first suction amount is larger than the second suction amount when the job meets a preset condition.

  According to this configuration, since the control is performed only for a necessary job, it is possible to suppress unnecessary control execution and inconvenience associated therewith.

  In the present embodiment, the preset condition includes at least one of the basis weight of the paper P, the thickness of the paper P, and the rigidity of the paper P.

  In the case of thin paper or the like, wrinkles or creases may occur on the paper P due to the paper P following the stepped shape of the suction conveyance unit 220. Therefore, as shown in the present embodiment, by considering the conditions regarding the paper P, it is possible to appropriately determine whether or not the job causes a wrinkle or a crease on the paper P. Thereby, the main control is executed on the weak paper P such as thin paper, and the inconvenience that the paper P is wrinkled or folded can be suppressed.

  In the present embodiment, when the job meets a predetermined condition, control is performed such that the first suction amount is larger than the second suction amount. However, the control unit 250 itself may determine whether or not the paper P is weak, such as thin paper, and may determine whether the control can be executed.

  Specifically, after the suction by the suction conveyance unit 220 is started, it is determined that the paper P is adsorbed to the second suction conveyance unit, and the paper P is adsorbed to the first suction conveyance unit within a certain time after the adsorption. If not, it is determined that the paper is not thin, and control is performed so that the first suction amount is larger than the second suction amount. On the other hand, after starting suction by the suction conveyance unit 220, it is determined that the paper P is adsorbed to the second suction conveyance unit, and the paper P is adsorbed to the first suction conveyance unit within a certain time after the adsorption For example, it is determined that the paper is thin, and control is not performed so that the first suction amount is larger than the second suction amount.

  The control unit 250 (1) performs this control (control that makes the first suction amount larger than the second suction amount) while sucking and transporting a predetermined number of sheets of paper P after the start of the job. (2) When it is determined that the control is to be performed, a control is applied to the subsequent paper P such that the first suction amount is larger than the second suction amount. May be.

  According to this configuration, even when the type of the paper P does not exist in the setting information or the paper P of a paper type different from the setting information is conveyed, it is determined whether control is necessary in the process of executing the job. can do.

  In the above-described embodiment, the second suction amount is set to zero as control such that the first suction amount is larger than the second suction amount. However, if the first suction amount is greater than the second suction amount, (1) the second suction amount may be reduced from the state before the control without setting the second suction amount to zero, (2) A method of increasing the first suction amount from the state before the control while maintaining the second suction amount may be used.

  In this embodiment, the suction conveyance unit 220 includes a single suction fan 227, a duct 228, and a shutter member 229. Here, the duct 228 includes openings 228a1 to 228b2 that are divided to correspond to the first suction conveyance unit and the second suction conveyance unit, and are respectively opened. The shutter member 229 blocks the duct internal passage corresponding to the belt members 221a and 221d on both sides.

  According to this configuration, this control can be easily realized by operating the shutter member 229.

  The shutter member 229 adjusts the area of the variable opening set in the duct internal passage in addition to the configuration in which the duct internal passage corresponding to the belt members 221a and 221d on both sides can be switched between blocking and opening. It may be something like this.

  In the present embodiment, a single suction fan 227 is shared. However, a suction fan may be provided for each of the divided ducts, and the suction amount may be controlled by adjusting the air volume of the suction fan.

  In the present embodiment, the openings 228a1 and 228a2 opened to face the first suction conveyance unit are further downstream in the paper conveyance direction than the openings 228b1 and 228b2 opened to face the second suction conveyance unit. Arranged on the side.

  According to this configuration, suction on both sides of the paper P can be performed on the leading end side of the paper P. For this reason, when the second suction amount is increased, the leading edge of the sheet P is sucked up, so that it is suppressed that the leading end of the sheet P is suspended. As a result, it is possible to suppress a situation in which the paper P interferes with a paper guide or the like and a conveyance failure occurs.

  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 a paper feeding device is incorporated as part of the image forming system, the control unit provided in the image forming device may realize the function of the control unit provided in the paper feeding device.

  Moreover, in this embodiment, although the conveyance part was comprised with the several belt member, you may comprise with one wide belt member. Moreover, you may comprise a conveyance part with members other than a belt member. In the present embodiment, the suction conveyance unit has a stepped shape with a concave center, but may have a stepped shape other than this. For example, a step shape may be employed in which only one end region in the paper width direction is the first distance, and the remaining regions (the center region and the other end region) in the paper width direction are the second distance.

DESCRIPTION OF SYMBOLS 100 Image forming apparatus 200 Large-capacity paper feeding device 210 Paper feeding unit 211 Paper placing table 212 Front end regulating member 213 Rear end regulating member 214 Guide rail 220 Suction conveyance unit 221 conveyance units 221a, 221b, 221c, 221d Belt member 222 Drive source 223a , 223b, 223c, 223d Driving roller 224a, 224b, 224c, 224d Driven roller (upper side)
225a, 225b, 225c, 225d driven roller (lower side)
226 Suction part 227 Suction fan 228 Duct 228a, 228b Duct part 228a1, 228a2 Opening part 228b1, 228b2 Opening part 228c Partition 229 Shutter member 230 Front air blowing part 240 Side end air blowing part 250 Control part 251a, 251b Paper adsorption sensor

Claims (14)

In a paper feeding device that feeds paper from a paper placing table on which one or more sheets are placed,
A suction conveyance unit that sucks and conveys the paper placed on the paper placement table;
A control unit for controlling the suction amount of the suction conveyance unit,
The suction conveyance unit is
A first suction conveyance unit in which a distance to the paper placed on the paper placement table is set to a first distance;
A second suction conveyance unit set to a second distance that is smaller than the first distance, the distance to the paper placed on the paper placement table,
The first suction transport unit and the second suction transport unit are arranged in parallel with the paper transport direction, the first suction transport unit sucks an end region in the paper width direction of the paper, and the second suction transport unit Suction the central region of the paper in the paper width direction from the first suction conveyance unit,
The sheet feeding device, wherein the control unit controls the first suction conveyance unit and the second suction conveyance unit with independent suction amounts.   When the control unit determines that the sheet is adsorbed to the second suction conveyance unit after the suction by the suction conveyance unit is started, the suction amount of the first suction conveyance unit is set to the second suction conveyance unit. 2. The sheet feeding device according to claim 1, wherein control is performed so as to be larger than a suction amount.   The control unit is configured such that the suction amount of the first suction transport unit becomes larger than the suction amount of the second suction transport unit when a predetermined time has elapsed after the suction start by the suction transport unit. The sheet feeding device according to claim 1, wherein control is performed.   The control unit performs control so that the suction amount of the first suction transport unit is larger than the suction amount of the second suction transport unit simultaneously with the start of suction by the suction transport unit. 1.   5. The control unit according to claim 1, wherein the control unit performs control such that the first suction amount is greater than the second suction amount when a job satisfies a preset condition. The paper feeder described in the above.   The sheet feeding device according to claim 5, wherein the condition includes at least one of a basis weight of the sheet, a thickness of the sheet, and a rigidity of the sheet.   The sheet feeding device according to claim 5, wherein the condition is a basis weight of a sheet specified by a user or an environment recognized by an image forming apparatus that is a sheet feeding destination. The first suction conveyance unit and the second suction conveyance unit are provided in the first suction conveyance unit, respectively, and further include a suction detection unit that detects the suction of the paper,
The control unit determines that the sheet is adsorbed to the second suction conveyance unit after starting the suction by the suction conveyance unit, and determines that the sheet is not adsorbed to the first suction conveyance unit within a predetermined time. 2. The sheet feeding device according to claim 1, wherein in such a case, control is performed so that a suction amount of the first suction conveyance unit is larger than a suction amount of the second suction conveyance unit. The sheet bundle placed on the sheet placing table further includes a side end blower that blows air to a side end parallel to the sheet conveying direction;
2. The control unit according to claim 1, wherein when it is determined that the sheet is attracted to the first suction conveyance unit, the air direction of the side-end air blowing unit is switched from a direction parallel to the sheet surface to an upward direction. To 8. The paper feeding device described in any one of 8. In the sheet bundle placed on the sheet placing table further has a tip air blowing unit that blows air on the tip portion parallel to the sheet width direction,
The control unit switches the wind direction of the front-end air blowing unit from a direction parallel to the sheet surface to an upward direction when it is determined that the sheet is adsorbed to the first suction conveyance unit. 9. A paper feeding device described in any one of 9 above. The suction conveyance unit is
With one suction fan,
A duct that is divided in correspondence with the first suction conveyance unit and the second suction conveyance unit, each having an opening, and
The shutter member which interrupts the passage in a duct corresponding to the 2nd above-mentioned suction conveyance part, or adjusts the area of the variable opening set up as the passage in the duct is provided. A paper feeder described in any of the above.   The opening corresponding to the first suction conveyance unit is disposed on the downstream side in the paper conveyance direction with respect to the opening corresponding to the second suction conveyance unit. Paper feeder.   The control unit performs control so that the suction amount of the first suction conveyance unit is larger than the suction amount of the second suction conveyance unit while sucking and conveying a predetermined number of sheets after the start of the job. When it is determined whether or not to perform the control, when the subsequent sheets are sucked and transported, the suction amount of the first suction transport unit is the suction amount of the second suction transport unit. The paper feeding device according to claim 1, wherein a control that is larger than that is applied. A paper feeding device according to any one of claims 1 to 13,
An image forming system comprising: an image forming apparatus that forms an image on a sheet fed from the sheet feeding device.

Images