JP7135611B2 - Paper feeder and image forming system - Google Patents

Description

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

2. Description of the Related Art In recent years, there has been known an image forming system that performs a series of various processes including image formation. This image forming system is configured by arranging one or more devices in series according to the specifications required by the user. Devices that make up an image forming system include an image forming device that forms an image, and a paper feeder that holds a large capacity of paper and feeds it to the image forming device (large-capacity paper feeder). be done.

The paper feeder includes a paper stacker on which a plurality of sheets stacked in the thickness direction, ie, a stack of sheets, is placed, and a paper feed unit for feeding the sheets. The paper feed unit feeds sheets (uppermost paper) one by one from a stack of sheets placed on the sheet stacking table. As a paper feed unit, a configuration is known in which paper is fed by suction, and the paper feed device has a side air blower that blows air to lift the paper on the side surface of the paper stack along the paper transport direction. It has

In this type of sheet feeding device, not only the topmost sheet but also the second and subsequent sheets float when the air is blown. Therefore, when the uppermost sheet of paper is sucked by the paper feed unit, the paper is fed after separating the second and subsequent sheets from the uppermost sheet. With such a configuration, if it takes a long time for the paper to float, the productivity will decrease. On the other hand, if an attempt is made to ensure productivity, there is a risk that a sufficient amount of time for handling the sheets cannot be ensured, resulting in the occurrence of double feeding. Further, when it is difficult to float the paper, there is a possibility that the paper cannot be sucked in time and the paper cannot be fed.

Therefore, for example, Japanese Patent Application Laid-Open No. 2002-200000 discloses a technique for increasing the amount of air blown to the side surface of a stack of sheets.

Japanese Unexamined Patent Application Publication No. 2014-1061

However, the amount of air blown to the sides of the stack of sheets depends on the configuration of the blower. Therefore, when a sufficient floating state cannot be obtained even with the upper limit air volume of the blower, there is a problem that a higher output blower is required.

SUMMARY OF THE INVENTION The present invention has been made in view of such circumstances, and an object of the present invention is to provide a paper feeder and an image forming system capable of reducing the time required for the paper to float, thereby realizing stable paper feed performance. That is.

In order to solve such a problem, one invention of the present application is a paper feeding device that sucks and feeds paper from a paper stack placed on a paper stack, and is arranged to separate the paper stack and levitate the paper. a pair of air outlets for blowing air toward the sides of the stack of sheets, a paper holding section that regulates the floating height of the paper by coming into contact with the upper side of the floating paper, and the height of one of the air outlets. The paper is floated in a first operation mode in which the height of the other blowing port is different and in a second operation mode in which the height of the paper holding portion is different between one side of the paper stack and the other side of the paper stack. and a control unit for performing blowing control for blowing air for causing the air to flow.
Further, another invention of the present application is a paper feeding device for sucking and feeding paper from a paper stack placed on a paper stack, wherein the paper stack is arranged to separate the paper stack, and air for floating the paper is supplied to the paper. A first operation mode in which a pair of air outlets that blow toward the side of the bundle, the height of one air outlet differs from the height of the other air outlet, and the amount of air blown from one air outlet and the other air outlet. and a control unit that performs blowing control for blowing air for floating the paper in a third operation mode in which the amount of air blown from the nozzle is different from that of the air blown from the nozzle.
Further, another invention of the present application is a paper feeding device for sucking and feeding paper from a paper stack placed on a paper stack, wherein the paper stack is arranged to separate the paper stack, and air for floating the paper is supplied to the paper. A pair of nozzles for blowing toward the side of the bundle, a paper holding section that regulates the floating height of the paper by coming into contact with the upper part of the floating paper, and the height of one nozzle and the height of the other nozzle. a second operation mode in which the height of the sheet presser is different between one side of the stack of sheets and the other side of the stack of sheets; a control unit that performs blowing control for blowing air for floating the paper in a third operation mode in which the air volume is different from that of the air blown from the other blowing port.
Further, another invention of the present application is a paper feeding device for sucking and feeding paper from a paper stack placed on a paper stack, wherein the paper stack is arranged to separate the paper stack, and air for floating the paper is supplied to the paper. A control unit that performs blowing control for blowing air for floating sheets in a first operation mode in which a pair of blowing openings blows toward the side of the bundle and the height of one blowing opening is different from the height of the other blowing opening. and the control unit further has a normal operation mode in which the height of one blowing port and the height of the other blowing port are the same as the operation mode in the blowing control, and information on the paper and the floating state of the paper. can be switched between a normal operating mode and a first operating mode based on either or both of make low.

In a second aspect of the present invention, in a paper feeding device for sucking and feeding paper from a paper stack placed on a paper stacking table, the paper stack is arranged to separate the paper stack, and air for floating the paper is supplied to the paper stack. a pair of nozzles for blowing toward the sides of the stack of paper, a paper holding section that regulates the floating height of the paper by coming into contact with the upper side of the floating paper, and the height of the paper holding section is on one side of the stack of paper. and a control unit that performs blowing control for blowing air for floating the sheets in a second operation mode different on the other side of the stack of sheets.

Further, another invention of the present application is a paper feeding device for sucking and feeding paper from a paper stack placed on a paper stack, wherein the paper stack is arranged to separate the paper stack, and air for floating the paper is supplied to the paper. Air for floating sheets in a third operation mode in which a pair of blowing openings for blowing toward the side of the bundle and a volume of air blown from one of the blowing openings is different from that of the air blowing from the other blowing opening. and a control unit that performs blowing control for blowing, and the control unit has an operation mode in blowing control in which the air volume blown from one blowing port and the air volume blown from the other blowing port are equal. It further has a normal operation mode, and is switchable between the normal operation mode and a third operation mode based on one or both of sheet information and a floating state of the sheet. The operation mode is switched based on the time until the paper suction unit located at the position sucks the paper .

Further, in the second invention, in addition to the second operation mode, the control unit performs blowing in a third operation mode in which the amount of air blown from one blowing port is different from the amount of air blown from the other blowing port. Control is preferred.

The first invention further comprises a duct that is connected to the blowing port and guides the air blown from the blower to the blowing port, and the duct is vertically movable to adjust the height of the blowing port. is preferred.

In this case, in the first invention, it is preferable that the duct is vertically movable by wind pressure of air.

Moreover, it is preferable that the first invention further includes a lock mechanism that regulates the movement of the duct and adjusts the height of the spray port.

Moreover, in the second invention, it is preferable that the paper holding portion is provided above the blowing port.

In this case, the second invention preferably further has a movable mechanism for adjusting the height of the sheet presser.

In the second invention, the control unit selects a normal operation mode in which the height of the paper holding portion is the same on one side surface of the paper bundle and on the other side surface of the paper bundle as the operation mode in the blowing control. It is preferable to further have and switch between the normal operation mode and the second operation mode based on one or both of sheet information and sheet floating state.

Further, in the first invention, when the amount of air blown from one blowing port is different from the amount of air blown from the other blowing port, the control unit adjusts the height of the blowing port with the larger air flow. It is preferable that the height be lower than the height of the blowing port with a smaller air volume.

In the first invention, when the amount of air blown from one blowing port is different from the amount of air blown from the other blowing port, the control unit selects the paper holding portion having a smaller air flow. It is preferable to make the height lower than that of the sheet presser having a larger amount of air.

A fourth aspect of the invention is an image forming system comprising a paper feeding device according to any one of the first to third aspects of the invention, and an image forming device for forming an image on the paper fed from the paper feeding device.

Another invention of the present application is an image forming system comprising: a paper feeding device for sucking and feeding paper from a stack of paper placed on a paper stacking table; An image forming apparatus for forming images, and a control unit for controlling the paper feeder and the image forming apparatus. The controller has a pair of blowing openings that blow toward the target, and the control unit selects a first operation mode in which the height of one blowing opening is different from the height of the other blowing opening , and the amount of air blown from one blowing opening and the other In a third operation mode in which the amount of air blown from the blowing port of the third operation mode is different from that of the blowing port of the third operation mode , the blowing control is performed to blow the air for floating the paper.

In a sixth aspect of the invention, in an image forming system, there is provided a paper feeding device for sucking and feeding paper from a stack of paper placed on a paper stacking table, and forming an image on the paper fed from the paper feeding device. and an image forming apparatus that controls the paper feeding device and the image forming device. It has a pair of blowing openings for blowing toward and a paper pressing section that regulates the floating height of the paper by coming into contact with the upper side of the floating paper. Blowing control for blowing air for floating the paper is performed in a second operation mode which is different between one side of the stack and the other side of the stack of sheets.

According to the paper feeding device and the image forming system according to the present invention, it is possible to reduce the time required for the paper to float, so that stable paper feeding performance can be achieved.

1 is a front view schematically showing the configuration of an image forming system according to this embodiment; FIG. Front view schematically showing the configuration of the paper feed unit A diagram schematically showing the configuration of the side end air blower Explanatory diagram showing the details of the side end air blower Explanatory diagram of normal operation mode Explanatory diagram of the first operation mode Explanatory diagram of the second operation mode Explanatory diagram of the third operation mode Flowchart showing the flow of paper feed processing Explanatory diagram of a table that defines the relationship between operation modes and paper information Explanatory drawing of a modified example of the paper pressing section

FIG. 1 is a front view schematically showing the configuration of an image forming system according to this embodiment. The image forming system is a system for performing predetermined processing including image formation on the paper P, and is composed of a plurality of devices. The image forming system of this embodiment includes an image forming apparatus 100 and a large-capacity paper feeder 200 . These devices are arranged in the order of the large-capacity paper feeding device 200 and the image forming device 100 from the upstream side to the downstream side in the sheet conveying direction, but each device is accommodated in the same housing. There may be.

The image forming apparatus 100 is a device that forms an image on a sheet P fed from the large-capacity sheet feeding device 200 or on a sheet P that it owns. The image forming apparatus 100 is, for example, an electrophotographic image forming apparatus, and forms a full-color image by arranging a plurality of photoreceptors in the vertical direction so as to face a single intermediate transfer belt. It is a color image forming apparatus. The image forming apparatus 100 mainly includes 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 integrated into one unit. Housed in a housing.

The document reader SC scans and exposes the document with an exposure device, reads the reflected light with a line image sensor, and thereby obtains an image signal. This image signal is subjected to processing such as A/D conversion, shading correction, compression, etc., and then input to the control unit 50 as image data. The image data to be input to the control unit 50 is not limited to the data read by the document reading device SC. It may be read from a portable recording medium such as a semiconductor memory.

The four sets of 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. It is composed of an image forming section 10C for forming an image and an image forming section 10K for forming a black (K) image.

The image forming section 10Y includes a photosensitive drum 11Y and a charging section, an optical writing section, 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 visualizes the latent image on the photosensitive drum 11Y by developing it 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 predetermined positions on the intermediate transfer belt 15, which is an endless belt, by the primary transfer roller.

The remaining image forming units 10M, 10C, and 10K are composed of photosensitive drums 11M, 11C, and 11K, and charging units, optical writing units, developing devices, and drum cleaners arranged therearound. are the same as those of the image forming section 10Y.

The image transferred onto the intermediate transfer belt 15 is transferred by the secondary transfer roller 16 onto the paper P conveyed by the paper conveying section 20 at a predetermined timing. The secondary transfer roller 16 is arranged 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 along the transport path. The paper transport unit 20 includes transport rollers, transport guides, and the like. Further, a sheet discharge roller 23 and a switching gate 24 to be described later also constitute a part of the sheet conveying section 20 .

The fixing device 40 is a device that applies a fixing process to 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 to the paper P while the paper P passes through the fixing nip, using pressure from the pair of fixing rollers and heat of the fixing rollers. The paper P that has undergone the fixing process is discharged outside the machine by the paper discharge roller 23 .

When image formation is also performed on the back surface of the paper P, the paper P on which the image formation on the front surface of the paper P has been completed is transported to the paper re-feed transport path by the switching gate 24 . In the paper re-feeding transport path, after the rear end of the transported paper P is nipped by the reversing rollers, the paper P is reversed by being reversed. The sheet P whose front and back sides have been reversed is transported by a plurality of transport rollers, and joins the transport path upstream of the secondary transfer roller 16 in order to form an image on the back surface of the sheet.

The control unit 50 controls operations of the image forming apparatus 100 . As the control unit 50, a microcomputer composed mainly of a CPU, ROM, RAM, and I/O interface can be used. The CPU controls operations 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. Also, the ROM stores data necessary for executing the program. The RAM is a memory that serves as a working storage area. Programs and data stored in the ROM are developed on the RAM when read by the CPU. Then, the CPU performs various processes based on the programs and data expanded on the RAM.

The operation panel 60 is an input unit that allows desired information to be input according to the information displayed on the display. As the operation panel 60, a touch panel system 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.) by operating the operation panel 60 . The set information is acquired by the control unit 50 . The operation panel 60 also functions as a display section for displaying various information to the user under the control of the control section 50 .

The large-capacity paper feeder 200 is a paper feeder that feeds paper P. As shown in FIG. The large-capacity paper feeder 200 includes one or more paper feed units 210, for example, three paper feed units 210 arranged in the upper, middle and lower stages, and a control section 250. These elements are combined into one. Housed in a housing.

FIG. 2 is a front view schematically showing the configuration of the sheet feeding unit 210. As shown in FIG. The paper feed unit 210 accommodates a plurality of sheets P (sheet bundle), and feeds the sheets P (top sheet P) from the sheet bundle one by one. The paper feed unit 210 mainly includes a paper stacking table 211, a leading end regulating member 212, a trailing end regulating member 213, a side end regulating member 214, a paper feeding section 220, a leading end air blowing section 230, and a side end blowing section 240. . A guide rail 215 is provided in the paper feed unit 210 , and the paper feed unit 210 is configured to be able to be pulled out from the housing of the large-capacity paper feeder 200 .

In the paper feed unit 210 , the paper stack is placed on the paper stack table 211 . The paper stacking table 211 is provided with an electric lifting mechanism, and is configured to be vertically movable.

The leading end regulating member 212 regulates the leading end of each sheet P placed on the sheet stacking table 211, that is, the surface (leading end surface) of the sheet bundle positioned downstream in the sheet conveying direction.

The trailing edge regulating member 213 regulates the trailing edge of each sheet P placed on the sheet stacking table 211, that is, the surface (trailing edge surface) of the sheet bundle positioned upstream in the sheet transport direction. The trailing end regulating member 213 is configured to be movable along the sheet conveying direction, and its position is adjusted according to the sheet size.

A height sensor (not shown) that detects the height of the stack of sheets placed on the sheet stacking table 211 is arranged on the trailing end regulating member 213 . The control unit 250 drives the lifting mechanism based on the signal from the height sensor, and controls the lifting and lowering of the paper stacking table 211 . By this control, the uppermost sheet P of the sheet bundle placed on the sheet stacking table 211 is maintained at a constant height.

The side edge regulating member 214 regulates the side edge of each sheet P placed on the sheet stacking table 211, that is, the surface (side surface) of the sheet bundle parallel to the sheet conveying direction. The side edge regulating members 214 are provided at two locations corresponding to both side surfaces (left and right side surfaces) of the sheet stack. In other words, the side end regulating members 214 are arranged to face each other while separating the sheet stack. One or both of the trailing end regulating members 213 are configured to be movable along a direction (paper width direction) orthogonal to the paper transport direction, and their position is adjusted according to the paper size.

The paper feeding unit 220 is arranged above the paper stacking table 211 (paper P) so as to face the paper stacking table 211 . The paper feeding unit 220 is arranged in a state separated by a certain distance from the uppermost paper sheet P of the paper stack placed on the paper stacking table 211 . The paper feeding unit 220 sucks the paper P (the uppermost paper P) floated from the paper stack by blowing air, and feeds the paper to the transport path. The paper feeding section 220 is mainly composed of a conveying section 221 and a suction section 226 .

The transport unit 221 has a function of transporting (feeding) the adsorbed paper P forward, and includes an endless adsorption belt 221a, and a drive roller 221b and a driven roller 221c over which the adsorption belt 221a is stretched. It has The suction belt 221a rotates when the drive roller 221b is driven to rotate, and the belt area (lower belt area) facing the paper P moves in the paper transport direction. The suction belt 221a is provided with a plurality of through holes (not shown) each having a small diameter.

The suction unit 226 sucks the floated paper P and attaches it to the suction belt 221a. The suction unit 226 is arranged inside the suction belt 221a and faces the paper P across the suction belt 221a. The suction unit 226 includes a suction fan that sucks air, and a duct that is arranged inside the suction belt 221a and guides the air to the suction fan. A suction port facing the suction belt 221a is provided in the lower part of the duct. When the suction fan operates, a negative pressure is created inside the suction belt 221a. As a result, an air flow is formed from the lower side of the suction belt 221a toward the duct, and the paper P is sucked.

Further, the paper feeding unit 220 is provided with an adsorption sensor (not shown) that detects adsorption of the paper P to the adsorption belt 221a. Information detected by the adsorption sensor is read by the control unit 250 .

The front end air blowing unit 230 is arranged near the paper feed unit 220 on the front end surface of the sheet bundle. The front end air blowing unit 230 blows air from the front end side of the paper stack placed on the paper stacking table 211 . By this blowing, air is introduced between the topmost sheet P and the second and subsequent sheets P, so that the topmost sheet P and the second and subsequent sheets P can be separated.

The tip air blower 230 mainly includes a blower 231 and a blower port 232 . The blower 231 is, for example, a multi-blade fan (sirocco fan). The blower port 232 blows the air blown from the blower 231 toward the top of the sheet stack.

FIG. 3 is a diagram schematically showing the configuration of the side end air blower 240. As shown in FIG. The side end air blowing units 240 are arranged at two locations corresponding to the left and right side surfaces of the stack of sheets. In this embodiment, the side air blower 240 is provided inside the side regulating member 214 . Similar to the pair of side end regulating members 214, the pair of side end air blowing units 240 are arranged to face each other with the sheet bundle separated. The individual side end air blowing units 240 are configured symmetrically with respect to the stack of sheets.

The side end blower section 240 includes a blower 241 , a duct 242 , a blowing port 243 and a paper pressing section 244 . The blower 241 is, for example, a multi-blade fan (sirocco fan), and blows air. The duct 242 guides the air blown from the blower 241 to the blowing port 243 . The duct 242 is configured such that air flows vertically. A spray port 243 is connected to the upper portion of the duct 242 . The blowing port 243 blows the air flowing through the duct 242 toward the side surface of the sheet stack. The air blown from the blowing port 243 to the side surface of the bundle of sheets functions as air for floating the uppermost sheet P. As shown in FIG. The paper holding portion 244 regulates the floating height of the paper P by contacting the uppermost paper P that floats from above. The sheet presser 244 is provided above the blowing port 243 and extends toward the center of the sheet stack. A movable mechanism 245 that adjusts the height is connected to the sheet presser 244 . The operation of the movable mechanism 245 is controlled by the controller 250 .

FIG. 4 is an explanatory diagram showing the details of the side end air blower 240. As shown in FIG. In the side end blowing section 240, the duct 242 is vertically movable within a movable range from the upper limit position to the lower limit position. When the blower 241 is stopped, the duct 242 remains at the lower limit position due to its own weight, as shown in FIG. 4(a). On the other hand, when the blower 241 is operating, the duct 242 rises to the upper limit position due to the wind pressure of the air blown from the blower 241 and remains at that position, as shown in FIG. 4(b). When the blower 241 stops, the duct 242 descends to the lower limit position due to its own weight, as shown in FIG. 4(a).

As one of the features of this embodiment, the side end air blower 240 has a lock mechanism 246 . A lock mechanism 246 limits the movement of the duct 242 and adjusts the height of the spray port 243 . As the lock mechanism 246, a method using an abutting member, a method using a solenoid, or the like can be considered. The abutting member is configured to be able to advance above the duct 242 when the duct 242 is at the lower limit position. When the abutting member advances, even if the blower 241 operates, the duct 242 abuts against the abutting member, thereby restricting the rise of the duct 242 . On the other hand, as a method using a solenoid, the plunger of the solenoid is connected with the duct 242 . When the solenoid is pulled, even if the air blower 241 operates, the duct 242 is connected to the plunger, so the upward movement of the duct 242 is restricted. By operating the lock mechanism 246 in this manner, the duct 242 is restricted to the lower limit position even if the blower 241 operates (FIG. 4(c)). The operation of lock mechanism 246 is controlled by control unit 250 .

Thus, the height of the blowing port 243 connected to the duct 242 is adjusted according to the elevation of the duct 242 . When the duct 242 is located at the upper limit position, that is, when the blower 241 operates and receives air pressure, the blowing port 243 is at a preset normal blowing position (FIG. 4(b)). . At the normal blowing position, only the lower area of the blowing opening 243 faces the side surface of the stack of sheets, and the upper area of the blowing opening 243 protrudes above the uppermost paper sheet P. As shown in FIG. On the other hand, when the duct 242 is positioned at the lower limit position, that is, when the blower 241 is stopped, or when the lock mechanism 246 is operated even when the blower 241 is operating, the blowing port 243 is normally closed. It is set at a position lower than the spray position. At this position, almost the entire area of the blowing port 243 faces the side surface of the stack of sheets.

By adjusting the height of the blowing port 243, it is possible to adjust the area of the blowing port 243 facing the side surface of the sheet stack. When the area of the blowing port 243 that faces the side surface of the sheet bundle is narrow, the proportion of the air that is blown to the side surface of the sheet bundle among the air that is output from the blowing port 243 decreases. On the other hand, when the area of the blowing port 243 facing the side surface of the sheet bundle is wide, the proportion of the air blown from the blowing port 243 to the side surface of the sheet bundle increases. That is, by adjusting the height of the blowing port 243, it is possible to adjust the ratio of the air blown to the side surface of the sheet stack.

The control unit 250 controls the operation of the large-capacity paper feeder 200 . As the control unit 250, a microcomputer composed mainly of a CPU, ROM, RAM, and 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. Also, the ROM stores data necessary for executing the program. The RAM is a memory that serves as a working storage area. Programs and data stored in the ROM are developed on the RAM when read by the CPU. Then, the CPU performs various processes based on the programs and data expanded on the RAM.

In relation to the present embodiment, the control unit 250 executes a paper feed operation of feeding the paper P (top paper P) from the paper bundle. Specifically, the control unit 250 controls the suction unit 226 to suck the paper P (top paper P) from the paper stack placed on the paper stacking table 211 (suction control). At this time, the control unit 250 controls the side air blowing unit 240 to blow air for floating the paper P (blowing control). Next, when the control unit 250 determines that the sheet P is adsorbed through the adsorption sensor, the control unit 250 terminates the blowing control. Then, the control unit 250 controls the front end air blowing unit 230 to blow air from the front end side of the paper P, thereby handling the top paper P and the second and subsequent papers P (handling control). Similarly, the control unit 250 controls the conveying unit 221 to feed the paper P to the forward conveying path (conveyance control). When the paper P is fed to the transport path, the controller 250 terminates handling control and transport control. This series of paper feed operations is repeated for a new topmost paper sheet P each time the paper sheet P is fed.

An outline of spray control, which is one of the features of this embodiment, will be described. In the following description, the front end blower 230 facing the right side of the stack of sheets will be referred to as the right front end blower 230, and the front end blower 230 facing the left side will be referred to as the left front end blower 230 (leading end blower 230). are expressed in the same way).

The control unit 250 has a plurality of operation modes to control spraying. The control unit 250 basically performs spray control in the normal operation mode.

FIG. 5 is an explanatory diagram of the normal operation mode. In the normal operation mode, the left and right side end air blowers 240 are operated under the same conditions. Specifically, in the normal operation mode, the height of the left blowing port 243 and the height of the right blowing port 243 are aligned at the normal blowing position. Also, the height of the left sheet pressing portion 244 and the height of the right sheet pressing portion 244 are aligned. Furthermore, the volume of air blown from the left blowing port 243 and the volume of air blown from the right blowing port 243 are equal.

On the other hand, when determining a predetermined switching condition, the control unit 250 switches from the normal operation mode to the floating priority mode in which one side of the paper P is actively floated. The levitation priority mode is implemented by any one of a first operation mode, a second operation mode, and a third operation mode, which will be described later, or by combining two or more operation modes. In the following description, a form in which the right edge of the sheet P is floated will be described as an example.

FIG. 6 is an explanatory diagram of the first operation mode. The first operation mode is a mode in which the height of the right blowing port 243 and the height of the left blowing port 243 are different. Specifically, the height of the left blowing port 243 is set to the normal blowing position, and the height of the right blowing port 243 is set to a position lower than the normal blowing position. That is, the height of the right blowing port 243 is lower than the height of the left blowing port 243 .

At the blowing port 243 located at a lower position, the ratio of air blown to the side surface of the sheet stack is increased compared to the blowing port 243 located at the normal blowing position. Therefore, on the right side of the stack of sheets, the amount of air entering between the sheets P increases, so that the right edge of the sheet P floats significantly.

When the right edge of the paper P floats significantly, the floated area of the paper P approaches the paper feeding unit 220, so that the assist by the suction of the paper feeding unit 220 can be received. Therefore, even if the entire sheet P is not floated, the right edge of the sheet P can be attracted to the sheet feeder 220 . Therefore, even if the paper P takes a long time to float when the air is blown evenly from both sides in the normal operation mode, the floating priority mode (first operation mode) is applied to actively blow only one side of the paper P. By levitation, the time required for levitation can be reduced. As a result, it is possible to ensure stable sheet feeding performance.

FIG. 7 is an explanatory diagram of the second operation mode. The second operation mode is a mode in which the height of the right paper pressing portion 244 and the height of the left paper pressing portion 244 are different. Specifically, the height of the left paper pressing portion 244 is set lower than the height of the right paper pressing portion 244 .

In this case, at the left edge of the sheet P, the sheet pressing portion 244 restricts the floating of the sheet P. As shown in FIG. On the other hand, since the right edge of the paper P is sufficiently far from the paper pressing portion 244, the paper P is allowed to float. When air is blown in this state, the left paper holding portion 244 serves as a fulcrum, and the right edge of the paper P floats significantly.

When the right edge of the paper P floats significantly, the floated area of the paper P approaches the paper feeding unit 220, so that the assist by the suction of the paper feeding unit 220 can be received. Therefore, even if the entire sheet P is not floated, the right edge of the sheet P can be attracted to the sheet feeder 220 . Therefore, even if the paper P takes a long time to float when the air is blown evenly from both sides in the normal operation mode, the floating priority mode (second operation mode) is applied to actively blow only one side of the paper P. By levitation, the time required for levitation can be reduced. As a result, it is possible to ensure stable sheet feeding performance.

FIG. 8 is an explanatory diagram of the third operation mode. The third operation mode is a mode in which the amount of air blown from the right blowing port 243 differs from the amount of air blown from the left blowing port 243 . Specifically, the amount of air blown from the right blowing port 243 is increased. In this case, the ratio of the air blown to the side surface of the sheet stack from the right blowing port 243 increases. Therefore, at the right edge of the sheet P, the amount of air entering between the sheets of the sheet bundle increases, so the floating amount increases.

When the right edge of the paper P floats significantly, the floated area of the paper P approaches the paper feeding unit 220, so that the assist by the suction of the paper feeding unit 220 can be received. Therefore, even if the entire sheet P is not floated, the right edge of the sheet P can be attracted to the sheet feeder 220 . Therefore, even if the paper P takes a long time to float when the air is blown evenly from both sides in the normal operation mode, the floating priority mode (third operation mode) is applied to actively blow only one side of the paper P. By levitation, the time required for levitation can be reduced. As a result, it is possible to ensure stable sheet feeding performance.

When the first operation mode and the third operation mode are combined, the height of the blowing port 243 with the larger air volume should be lower than the height of the blowing port 243 with the smaller air volume. is preferred. Similarly, when the second operation mode and the third operation mode are combined, the height of the paper holding portion 244 with the smaller air volume is made lower than the height of the paper holding portion 244 with the larger air volume. is preferred.

Switching between the normal operation mode and the floating priority mode is performed based on one or both of the information on the paper P and the floating state of the paper P. The information of the paper P is the basis weight and the paper length. If the sheet P has a large basis weight or a large sheet length, it may take time to float even if air is blown in the normal operation mode. Therefore, the control unit 250 can determine switching of the operation mode according to the information on the paper P. FIG. As a result, the time required for floating can be reduced, and stable paper feeding can be ensured. Further, by monitoring the actual floating state of the paper P, the control unit 250 can determine switching of the operation mode according to the paper P that takes time to float. As a result, the time required for floating can be reduced, and stable paper feeding can be ensured.

The operation of the image forming system according to the present embodiment, more specifically, the paper feeding process of the paper P in the large-capacity paper feeding device 200 will be described below. Here, FIG. 9 is a flow chart showing the flow of paper feed processing. The processing shown in this flowchart is executed by the control unit 250 with a paper feed job as a trigger.

First, in step S10, the control unit 250 initializes the operation mode. In initial setting, the control unit 250 reads information about the paper P to be fed. Then, the control unit 250 determines the operation mode based on a table (see FIG. 10) that defines the relationship between the operation mode and information about the paper P (basis weight and paper length).

In step S11, the control unit 250 performs the paper feed operation for the top sheet P of the sheet bundle. Specifically, the controller 250 performs suction control, spray control, separation control, and transport control. In this case, blowing control is performed in the operation mode determined in step S10.

In step S12, the control unit 250 calculates the floating time T, which is the time from the start of the paper feeding operation, that is, the time from when the paper P floats until the paper P is detected by the adsorption sensor.

In step S13, the controller 250 determines whether or not the ascent time T is equal to or greater than the first threshold value T1. The first threshold value T1 is a threshold value for judging whether the ascent state is slower than the normal ascent time, and an optimum value is set through experiments and simulations. If the ascent time T is equal to or greater than the first threshold value T1, an affirmative determination is made in step S13, and the process proceeds to step S14. On the other hand, if the floating time T is smaller than the first threshold value T1, a negative determination is made in step S13, and the process proceeds to step S15.

In step S14, the control unit 250 switches the operation mode to the levitation priority mode. If the operation mode has already been switched to the floating priority mode prior to step S14, the floating priority mode is continued. In this case, among the floating priority modes, if there is an operation mode that has not yet been implemented, that operation mode may be added. For example, if only the first operational mode is implemented, one or both of the second and third operational modes may be added.

In step S15, the controller 250 determines whether or not the ascent time T is less than the second threshold T2. The second threshold value T2 is a threshold value for judging an ascent state earlier than the normal ascent time, and an optimum value is set through experiments and simulations. If the ascent time T is shorter than the second threshold value T2, an affirmative determination is made in step S15, and the process proceeds to step S16. On the other hand, if the floating time T is equal to or greater than the second threshold value T2, a negative determination is made in step S15, and the process proceeds to step S17.

In step S16, control unit 250 switches the operation mode to the normal operation mode. If the current levitation priority mode is implemented in a plurality of operation modes, the levitation priority mode may be continued by reducing the number of operation modes instead of immediately switching to the normal operation mode. For example, when the first operation mode, the second operation mode, and the third operation mode are combined to implement the floating priority mode, one or two of the operation modes are stopped.

In step S17, the control section 250 determines whether or not the paper feeding job has ended. If the paper feeding job has ended, an affirmative determination is made in step S17, and this routine ends. On the other hand, if the paper feeding job has not ended, a negative determination is made in step S17, and the process returns to step S11.

As described above, in the present embodiment, the large-capacity paper feeder 200 operates in the first operation mode in which the height of one blowing port 243 and the height of the other blowing port 243 are different, and the height of the sheet holding portion 244 is set to the height of the sheet bundle. A second operation mode that differs between one side face and the other side face of the bundle of sheets, and a second mode in which the air volume blown from one blowing port 243 and the air blowing volume from the other blowing port 243 are different. By combining one or more of the three operation modes, air blowing control for blowing air for floating the paper P is performed.

According to this configuration, one side of the paper P can be floated to a large extent. Therefore, since the area where the paper P floats approaches the paper feeding unit 220, the assist by the suction of the paper feeding unit 220 can be received. Therefore, even if the entire sheet P is not floated, the right edge of the sheet P can be attracted to the sheet feeder 220 . Therefore, even if the paper P takes a long time to float when air is evenly blown from both sides in the normal operation mode, by applying the floating priority mode and actively floating only one side of the paper P, It is possible to reduce the time required for ascent. As a result, it is possible to ensure stable sheet feeding performance.

Note that, in this embodiment, the sheet holding portions 244 are arranged on both sides of the sheet bundle. However, as shown in FIG. 11, a single sheet presser 244 may be used that extends from one side of the stack of sheets to the other.

In addition, in this embodiment, the height adjustment of the blowing port 243 and the height adjustment of the paper holding portion 244 are performed separately, so that a movable mechanism 245 for moving the paper holding portion 244 is provided. However, even if the paper holding portion 244 is provided above the blowing port 243 so as to be rotated by the air output from the blowing port 243, and its height is adjusted according to the elevation of the duct 242. good.

Further, in the present embodiment, the height of the blowing port 243 is adjusted by a configuration in which the duct 242 is moved by the wind pressure of the air of the blower 241 and a configuration in which this movement is restricted by the lock mechanism 246 . However, all or part of the side end air blower 240 may be movable by an electric lifting mechanism. Further, in this embodiment, the height of the blowing port 243 is adjusted in two stages, the normal blowing position and the lowest position. However, the height of the spray port 243 may be adjusted in multiple steps or linearly between the normal spray position and the lowest position.

Although the image forming system according to the embodiment of the present invention has been described above, it goes without saying that the present invention is not limited to the above-described embodiment, and various modifications are possible within the scope of the invention. . Further, not only the image forming system but also the sheet feeding device (large-capacity sheet feeding device) that constitutes the image forming system itself functions as a part of the present invention. Furthermore, the present invention may be applied to a paper feeding unit incorporated in an image forming apparatus, in which case the image forming apparatus can also function as part of the present invention.

Further, when the image forming system is composed of an image forming apparatus and a paper feeder, the image forming apparatus and the paper feeder may each have a control function. A configuration including a control function may be employed. 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 paper feeder.

100 Image forming apparatus 10Y, 10M, 10C, 10K Image forming unit 11Y, 11M, 11C, 11K Photoreceptor drum 15 Intermediate transfer belt 16 Secondary transfer roller 20 Paper conveying unit 21 Paper tray 22 Paper feed roller 23 Paper discharge roller 24 Switching Gate 40 Fixing device 50 Control unit 60 Operation panel 200 Large-capacity paper feeding device 210 Paper feeding unit 211 Paper mounting table 212 Leading edge regulation member 213 Trailing edge regulation member 214 Side edge regulation member 215 Guide rail 220 Paper supply unit 221 Conveying unit 221a Adsorption Belt 221b Drive Roller 221c Driven Roller 226 Suction Part 230 Tip Blower Part 231 Blower 232 Blower Port 240 Side End Blower Part 241 Blower 242 Duct 243 Blower Port 244 Paper Holding Part 245 Movable Mechanism 246 Lock Mechanism 250 Control Part

Claims (19)

In a paper feeding device that sucks and feeds paper from a stack of paper placed on a paper table,
a pair of blowing ports arranged across the stack of paper and blowing air toward the sides of the stack of paper for floating the paper;
a paper holding portion that regulates the floating height of the paper by coming into contact with the upper side of the floating paper;
a first operation mode in which the height of one blowing port differs from that of the other blowing port ; a control unit that performs blowing control for blowing air to float the paper in two operation modes ;
A paper feeder having a In a paper feeding device that sucks and feeds paper from a stack of paper placed on a paper table,
a pair of blowing ports arranged across the stack of paper and blowing air toward the sides of the stack of paper for floating the paper;
A first operation mode in which the height of one blowing port is different from the height of the other blowing port , and a third operation mode in which the volume of air blown from the one blowing port and the volume of air blown from the other blowing port are different. a control unit that performs blowing control for blowing air to float the paper in the operation mode ;
A paper feeder having a In a paper feeding device that sucks and feeds paper from a stack of paper placed on a paper table,
a pair of blowing ports arranged across the stack of paper and blowing air toward the sides of the stack of paper for floating the paper;
a paper holding portion that regulates the floating height of the paper by coming into contact with the upper side of the floating paper;
A first operation mode in which the height of one blowing port and the height of the other blowing port are different, and a second operation mode in which the height of the paper pressing portion is different between one side of the stack of sheets and the other side of the stack of sheets. In an operation mode and a third operation mode in which the amount of air blown from one of the blowing ports is different from the amount of air blown from the other of the blowing ports, blowing control is performed to blow air to float the paper. a control unit;
A paper feeder having a further comprising a duct connected to the blowing port and guiding air blown from the blower to the blowing port;
4. The sheet feeding device according to claim 1 , wherein the duct is vertically movable to adjust the height of the blowing port. 5. A sheet feeding device according to claim 4 , wherein said duct is vertically movable by air pressure. 6. The sheet feeding device according to claim 5 , further comprising a lock mechanism that regulates the movement of the duct and adjusts the height of the blowing port. In a paper feeding device that sucks and feeds paper from a stack of paper placed on a paper table,
a pair of blowing ports arranged across the stack of paper and blowing air toward the sides of the stack of paper for floating the paper;
a control unit that performs blowing control for blowing air for floating a sheet in a first operation mode in which the height of one blowing port is different from the height of the other blowing port;
has
The control unit
Further, as an operation mode in the blowing control, a normal operation mode in which the height of the one blowing port and the height of the other blowing port are the same,
Switching between the normal operation mode and the first operation mode is possible based on one or both of paper information and a floating state of the paper,
In the first operation mode, the height of the one blowing port or the other blowing port is lower than the height in the normal operation mode . In a paper feeding device that sucks and feeds paper from a stack of paper placed on a paper table,
a pair of blowing ports arranged across the stack of paper and blowing air toward the sides of the stack of paper for floating the paper;
a paper holding portion that regulates the floating height of the paper by coming into contact with the upper side of the floating paper;
a control unit that performs blowing control for blowing air for floating the paper in a second operation mode in which the height of the paper presser is different between one side of the paper bundle and the other side of the paper bundle;
A paper feeder having a In addition to the second operation mode, the control unit operates in a third operation mode in which the amount of air blown from one of the pair of blow holes is different from the amount of air blown from the other blow hole. 9. The sheet feeding device according to claim 8 , wherein said blowing control is performed by: The control unit
As an operation mode in the blowing control, a normal operation mode is further provided in which the height of the paper holding portion is the same on one side surface of the paper bundle and on the other side surface of the paper bundle,
9. The paper feeding device according to claim 8 , wherein switching between the normal operation mode and the second operation mode is performed based on one or both of sheet information and a floating state of the sheet. In a paper feeding device that sucks and feeds paper from a stack of paper placed on a paper table,
a pair of blowing ports arranged across the stack of paper and blowing air toward the sides of the stack of paper for floating the paper;
a control unit that performs blowing control to blow air for floating a sheet in a third operation mode in which the amount of air blown from one blowing port differs from the amount of air blown from the other blowing port;
has
The control unit
Further, as an operation mode in the blowing control, a normal operation mode in which the air volume blown from the one blowing port and the air volume blown from the other blowing port are the same,
Switching between the normal operation mode and the third operation mode is possible based on one or both of paper information and a floating state of the paper,
A paper feeding device that switches between operation modes based on the time from when the paper is floated to when the paper is sucked by the paper suction unit located above the stack of paper. 10. The paper feeding device according to claim 1 , wherein said sheet presser is provided above said blowing port. 13. The paper feeder according to claim 12 , further comprising a movable mechanism for adjusting the height of said paper presser. 11. The paper feeder according to claim 7 , wherein the controller switches the operation mode based on the time from when the paper is floated to when the paper is sucked by the paper suction unit positioned above the paper stack. When the volume of air blown from one of the blowing openings is different from the volume of air blown from the other blowing opening, the control unit adjusts the height of the blowing opening with a larger air volume to the height of the air blowing opening. 4. The sheet feeding device according to claim 2 , wherein the height of said blowing port is set lower than the height of said blowing port of which air volume is smaller. When the amount of air blown from one of the blowing openings is different from the amount of air blown from the other blowing opening, the control unit adjusts the height of the paper holding unit with the smaller air amount to 10. The sheet feeding device according to claim 3 or 9 , wherein the sheet holding portion is set lower than the sheet holding portion having a larger air volume. a sheet feeding device according to any one of claims 1 to 16 ;
an image forming apparatus for forming an image on a sheet fed from the sheet feeding device;
An image forming system having a paper feeding device that sucks and feeds paper from a stack of paper placed on a paper table;
an image forming device that forms an image on paper fed from a paper feeding device;
a control unit that controls the paper feeding device and the image forming device;
The paper feeding device
having a pair of blowing ports arranged to separate the stack of paper and blowing air toward the side surface of the stack of paper for floating the paper;
The control unit
A first operation mode in which the height of one blowing port is different from the height of the other blowing port , and a third operation mode in which the volume of air blown from the one blowing port and the volume of air blown from the other blowing port are different. An image forming system that controls air blowing to float the paper in operation mode . a paper feeding device that sucks and feeds paper from a stack of paper placed on a paper table;
an image forming device that forms an image on paper fed from a paper feeding device;
a control unit that controls the paper feeding device and the image forming device;
The paper feeding device
a pair of blowing ports arranged across the stack of paper and blowing air toward the sides of the stack of paper for floating the paper;
a sheet presser that regulates the floating height of the sheet by coming into contact with the upper part of the sheet that floats,
The control unit
An image forming system that performs blowing control for blowing air for floating a sheet in a second operation mode in which the height of the sheet presser is different between one side of the sheet bundle and the other side of the sheet bundle.

Images