JP2010105777A - Paper feeding device and image forming device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a paper feeding device of large capacity, eliminating weak points in strength of a paper stacking base in relation to paper from a large size to a microsize, and simply, easily and stably performing width regulation and switching of an air blowing state according to paper of various kinds of weight, and also to provide an image forming device provided with the device. <P>SOLUTION: This paper feeding device has a paper stacking tray provided with: the paper stacking base having a mechanism to stack paper and drive so that paper of a top part may be at a prescribed position; a separation means for separating the paper of the top part at the prescribed position one sheet by one sheet; a paper feeding and conveying means for conveying the paper separated by the separation means to the next process; paper guide side plates disposed on both sides to regulate the position of the width direction of the stacked paper to a prescribed position; and a paper distal end positioning part for regulating a distal end position of the stacked paper. Auxiliary guide members setting paper further smaller than the minimum width of paper set by the paper guide side plates made movable, are provided to be switchable on the paper guide side plates. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a sheet feeding tray, particularly a sheet feeding device that feeds sheets one by one on a large capacity sheet loading tray, and an image forming apparatus including the sheet feeding device.

  Recently, an electrophotographic image forming apparatus has been utilized as a light printing apparatus, and has attracted attention as a means for producing printed materials of various media. For this reason, not only is it necessary to guarantee a stable printing position and sharpness on the paper, but printing on a large amount of paper across various sizes and papers can continue to be produced without reducing production efficiency. It is desired. Therefore, about 2000 sheets of paper can be placed on it, and it can be easily switched from a large size to a small size. Paper feeders are desired.

  However, apart from the large size side, the large size paper feeding device that can be used by switching to a postcard size up to about B5 size on the small size side is almost impossible due to the structure of the paper stacking base. Recently, however, there has been an increasing demand for large-scale printing on extremely small paper such as postcard size.

In addition, along with the switching of the size and the amount of wrinkles, it is necessary to provide air blowing means for separating the upper sheet in order to assist width regulation by the sheet guide side plate and separation of one sheet provided near the sheet guide side plate. Has been made. For example, Patent Document 1 deals with this by changing the air blowing position according to the switching setting conditions of size and dredging amount. Moreover, in patent document 2, the spraying channel area is changed and the spraying port which is not applicable at the time of spraying to a small size is closed and dealt with. Further, in Patent Document 3 and Patent Document 4, the air blowing opening shape is changed, and the blowing nozzle of the air blowing opening is replaced each time. However, it is not preferable to change the position and shape of the opening and replace the spray nozzle because the structure becomes complicated and switching time is required.
JP 2001-247229 A JP-A-2005-75540 JP 2005-330079 A Japanese Patent No. 3940876

  The present invention eliminates the problems of the background art as described above, eliminates the weak point in the strength of the paper stacking base for the paper ranging from a large size to a very small size, and further various kinds of weights. To provide a large-capacity paper feeding device and an image forming apparatus provided with the paper feeding device capable of easily, reliably and stably switching the width regulation and air blowing state so as to be compatible with paper. To do.

This object is achieved by any of the following technical means 1-8.
1. A paper stacking table having a mechanism for loading paper and driving the uppermost paper so as to have a predetermined height;
A paper guide side plate disposed so as to be movable so as to regulate the position in the width direction of the paper stacked on the paper stacking base to a predetermined position;
A paper leading edge positioning portion that regulates a leading edge position of the paper loaded on the paper stacking table;
A paper trailing edge restricting portion for restricting a trailing edge position of the paper loaded on the paper loading table;
One sheet separation for separating the uppermost sheets stacked on the sheet stacking table one by one by blowing air from an air blowing opening provided on the sheet guide side plate and an air blowing opening provided on the sheet leading edge positioning unit. Means,
A paper stacking tray having
A paper feeding / conveying means provided on an upper part of the paper stacking tray for receiving the paper separated by the single sheet separating means and conveying it to the next process;
An auxiliary guide member for regulating a sheet having a width smaller than the minimum width of the sheet regulated by the sheet guide side plate;
A paper feeding device comprising:
2. 2. The paper feeding apparatus according to 1, wherein the paper feeding / conveying unit includes a suction paper feeding unit that receives the paper separated by the single sheet separating unit and a paper conveying unit.
3. An upper surface of the air outlet is set higher than the predetermined height and lower than a lowermost surface of the suction paper feeding unit, and a lower surface of the air outlet is set lower than the predetermined height. The sheet feeding device according to 1 or 2, wherein
4). The air volume of the air outlet and the air blow-up outlet are compared with data information predetermined for each paper size corresponding to the combination of the paper type and paper amount of the paper to be fed. 4. The paper feeding device according to any one of 1 to 3, wherein the paper feeding device is selected.
5). When the width of the paper is regulated by the paper guide side plate and when the width is regulated by switching to the auxiliary guide member, the data information is a first size data table for the normal size and a small size data table, respectively. 5. The paper feeding device according to 4, wherein the paper feeding device is used after being sorted into a data table of the second group.
6). The air volume of the air blowout port and the air blowout port can be varied by changing the rotational speed of the DC motor using a pulse width modulation method for the DC motor that drives the blower. Or the paper feeding device according to 5.
7). 7. The paper feeding apparatus according to claim 1, wherein the paper stacking tray can be pulled out from a base frame of the paper feeding apparatus.
8. An image forming apparatus comprising the paper feeding device according to claim 1.

  The present invention eliminates the weakness in the strength of the paper stacking base for papers ranging from large to very small, and further supports width regulation and air so that it can handle various types of paper and paper types. It is possible to obtain a large-capacity paper feeding device and an image forming apparatus provided with the paper feeding device so that the switching of the spraying state can be easily and reliably performed stably.

  An example of an embodiment of the present invention will be described with reference to the drawings.

  FIG. 1 is a front sectional view showing an internal configuration of a state in which a large capacity paper feeding device of the present invention is connected to an image forming apparatus incorporating a small capacity paper feeding cassette.

  The image forming apparatus 1 is a tandem color image forming apparatus having an intermediate transfer belt 50.

  The image forming apparatus 1 has a plurality of paper feed cassettes 20 built in the lower part. An image forming unit 40 and an intermediate transfer belt 50 are installed above the paper feed cassette 20, and an image reading unit 30 is installed on the upper part of the apparatus main body.

  The document set on the document feeding table a of the double-sided document automatic feeder 10 is conveyed toward the image reading unit 30 by various rollers.

  The paper feed cassette 20 can be pulled out to the front side of the apparatus (the front side of the paper in FIG. 1). A plurality of paper feed cassettes 20 contain white paper or the like, each of which is divided by size and has a small capacity of about 200 sheets. The paper contained in the built-in paper feed cassette 20 or the large capacity paper feed device 200 connected independently is constituted by a paper feed roller 21 or a suction paper feed unit 210 and a paper transport unit 220. A sheet is fed one by one by a sheet feeding / conveying means.

  The image forming unit 40 includes four sets of image forming engines 400Y, 400M, 400C, and 400K for forming toner images of Y, M, C, and K colors. The image forming engines 400Y, 400M, 400C, and 400K are arranged linearly from top to bottom in this order, and have the same configuration.

  The configuration of the image forming engine 400Y for yellow will be described as an example. The image forming engine 400Y includes a photoconductor 410 that rotates counterclockwise, a charging unit 420, an exposure unit 430, a developing unit 440, and a cleaning unit 450. The cleaning unit 450 is disposed to include a region facing the lowermost part of the photoconductor 410.

  The intermediate transfer belt 50 located at the center of the apparatus main body is endless and has a predetermined volume resistivity. The primary transfer roller (transfer unit) 510 is installed at a position facing the photoconductor 410 with the intermediate transfer belt 50 interposed therebetween.

  Next, an operation for forming a color image in the image forming apparatus 1 will be described.

  The photoconductor 410 is rotationally driven by a drive motor (not shown) and is negatively charged (for example, −800 V) by the discharge of the charging unit 420. Next, the exposure unit 430 performs optical writing according to image information on the photoconductor 410 to form an electrostatic latent image. When the formed electrostatic latent image passes through the developing unit 440, the toner charged negatively in the developing unit adheres to the portion of the latent image by application of the negative developing bias, and the toner image is formed on the photoreceptor 410. It is formed. The formed toner image is transferred to the intermediate transfer belt 50 that is pressure-bonded to the photoreceptor 410. The toner remaining on the photoreceptor 410 after the transfer is cleaned by the cleaning unit 450.

  The toner images formed by the image forming engines 400Y, 400M, 400C, and 400K are transferred onto the intermediate transfer belt 50 in an overlapping manner by the primary transfer rollers 510. As a result, a color image is formed on the intermediate transfer belt 50. The sheets are fed one by one by the sheet feeding cassette 20 or the large-capacity sheet feeding apparatus 200, and are conveyed to the position of the registration roller 60 that functions as the registration conveyance unit through the conveyance path 22. The paper is abutted against the registration roller 60 and stops at one end, and the curling of the paper is corrected. The sheet is fed from the registration roller 60 at a timing when the image position coincides with the toner image on the intermediate transfer belt 50.

  The sheet fed by the registration roller 60 is guided by a guide plate and fed to a transfer nip position formed by the intermediate transfer belt 50 and the secondary transfer roller 70. At the transfer nip position constituted by the secondary transfer roller 70, the sheet is pressed toward the intermediate transfer belt 50 side. By applying a bias (for example, + 500V) having a polarity opposite to that of the toner to the transfer unit 70, the toner image on the intermediate transfer belt 50 is transferred to the sheet by the action of electrostatic force. The sheet is neutralized by a separation device (not shown) composed of a neutralizing needle and separated from the intermediate transfer belt 50, and sent to a fixing unit 80 composed of a heating roller, a pressure roller pair, or a heating belt and a pressure roller. It is done. As a result, the toner image is fixed on the paper, and the paper on which the image is formed is discharged to a paper discharge tray 25 outside the apparatus.

  The above describes the state in which image formation is performed on the first side, which is one side of a sheet as a recording medium. However, in the case of duplex copying, the sheet discharge switching member 26 is switched and the sheet guide 26A is opened. The paper is conveyed in the direction of the broken line arrow.

  Further, the paper is transported to the lower transport path 27B by the transport mechanisms 27A1 and 27A2, and is switched back by the roller pair 27C that forms the paper feed reversing portion of the paper feed transport device 27, and the transport path is switched by the branching section 27D. The rear end portion of the sheet thus far becomes the front end portion and is conveyed into the duplex copying paper supply unit 130.

  The sheet moves in the sheet feeding direction in the conveyance guide 131 provided in the duplex copying sheet feeding unit 130, and the sheet is re-fed by the sheet feeding roller 132 and guided to the conveyance path 22.

  Then, as described above, the sheet is conveyed in the direction of the secondary transfer roller 70, the toner image is transferred to the second surface, which is the back surface of the sheet, fixed by the fixing device 80, and then discharged onto the discharge tray 25. Make paper.

  Further, after the color image is transferred onto the sheet by the secondary transfer roller 70, the residual toner is removed from the intermediate transfer belt 50, which has separated the curvature of the sheet, by the cleaning unit 190A of the intermediate transfer belt.

  The image forming apparatus 1 according to the present embodiment forms a color image on a sheet by electrophotography, but the image forming apparatus according to the present invention is not limited to the present embodiment, and forms a monochrome image. It may be an image forming apparatus.

  In the process of creating such an image, residual toner on each photoconductor 410 and intermediate transfer belt 50 is collected by each cleaning unit 450, 190A, and then inside a pipe 605 provided with a spiral member. The toner is conveyed and sent to the waste toner box 600.

  Next, a sheet feeding apparatus 200 according to the present invention, which is particularly applied to feeding a large capacity sheet, will be described using the portion shown in the right half of the front sectional view of FIG. At the same time, FIG. 2 is a plan view seen from above the paper stacking tray 230 mounted on the paper feeding device 200, FIG. 3A is a rear view thereof, and FIG. 3B is a front view thereof. 2 and FIG. 4 which is a plan view showing a state where the paper stacking base 232 in FIG. 2 is removed.

  As shown in the right half of FIG. 1, the paper feeder 200 is provided with a base frame 201 and at least one paper stacking tray 230 that is housed in a housing 231. In the figure, two units are arranged at each of the upper and lower stages a and b of the base frame 201, and both hold the handle 230-1 from the base frame 201 on the near side in the figure via the slide rail 204. It is provided so that it can be pulled out, so that it can be easily loaded and maintained. Since the paper stacking trays 230 at each stage have the same configuration, only one of them will be described. For ease of explanation, the front panel of the housing 231 is removed from the a stage so that the inside can be seen.

  A sheet is sucked by an endless suction belt 212 wound around a guide roller 213 and a driving roller 214 provided around the suction duct chamber 211 on the upper side of the paper stacking tray 230 of the base frame 201 to rotate the suction belt 212. A suction paper feeding unit 210 that feeds paper in the moving direction is provided. Further, in the adjacent portion of the base frame 201 to the image forming apparatus 1, the sheet from the suction sheet feeding unit 210 is guided and a sheet feeding unit is formed by the conveying rollers 221 and 222 and the guide roller 223, for example, image formation. A paper transport unit 220 that transports the transport path 22 of the apparatus 1 is provided. The suction sheet feeding unit 210 and the sheet conveying unit 220 constitute a sheet feeding / conveying means.

  As shown in FIGS. 1 and 2, the paper stacking tray 230 includes a paper stacking base 232 that moves up and down in the casing 231, a paper leading edge positioning unit 240, a paper trailing edge regulating unit 250, a paper guide side plate 260 A, 260B, an auxiliary guide member 271 and a scale gauge portion 280 for clamping the width position confirmation are provided.

  The ends of the two wires 233A-1, 233A-2 and 233B-1, 233B-2 are fastened to the four corners of the paper stacking base 232 shown in FIG. At the same time, as shown in FIGS. 3A and 3B which are rear and front views of the sheet stacking tray 230, the wires are arranged on the panels 231A and B (front side) on the A (back) side of the casing 231. It is wound around two pulleys 234A-1, 234A-2, and 234B-1, 234B-2 on both sides fixed to the panel 231B. Further, winding pulleys 235A and 235B connected to a driving device 236 provided in the housing 231 are integrally and concentrically provided on the panels 231A and 231B on both sides of the housing 231. The other ends of the two wires 233A-1 and 233A-2 on one side are fastened to a winding pulley 235A provided on the A-side panel 231A. Similarly, the other ends of the two other wires 233B-1 and 233B-2 are fastened to a take-up pulley 235B provided on the B-side panel 231B. By driving and rotating the take-up drum 235, the paper stacking base 232 can be moved up and down stably and accurately.

  Referring again to FIG. 1, a paper leading edge positioning unit 240 is fixedly attached to the housing 231, and a sensor for detecting the position of the uppermost part of the paper stacked on the paper stacking base 232 is provided above the housing 231. 241 is provided. In response to the detection signal of the sensor 241, the paper stacking base 232 is driven by the driving device 236, and the position of the uppermost portion of the paper is held within a predetermined height range. In addition, an air blowing blower 242 that blows the uppermost sheet and helps to separate one sheet is directly connected to the motor and an air blowing port 243 is provided inside the sheet leading edge positioning unit 240. . In addition, the sheet trailing edge regulating unit 250 that regulates the position of the trailing edge of the sheet on the sheet stacking table 232 comes into contact with the trailing edge of the sheet and moves from the trailing edge to a line in the leading direction so that the position can be adjusted. The guide member 253 provided on the bottom 231D of the housing 231 is slidably provided.

  Further, as shown in FIG. 2, in order to restrict the position in the width direction of the sheets to be stacked, sheet guide side plates 260A and 260B having restriction surfaces 261 are provided on both sides in the width direction. First, a moving plate 268A having a rack gear 267A is attached to the bottom of the paper guide side plate 260A so that the paper guide side plate 260A on one side (A side) can move in the width direction. The rack gear 267A meshes with a pinion gear 267 that is fixed to the bottom 231D of the housing 231 and rotatably provided. In addition, two guide bars 269A-1 and 269A-2 are provided at the bottom 231D of the housing frame 231 with both ends fixed. The guide members 267A-1, 267A-2 provided integrally with the moving plate 268A having the rack gear 267A are slidably fitted to the guide bar 269A-1, and the guide member 267A-3 is slidably fitted to the guide bar 269A-2. Match.

  In addition, a moving plate 268B having a rack gear 267B is attached to the bottom of the paper guide side plate 260B so that the paper guide side plate 260B on the other side (B side) can be moved in the width direction. The rack gear 267B meshes with the pinion gear 267 fixed to the bottom portion 231D of the housing frame 231 and rotatably provided. In addition, two guide bars 269B-1 and 269B-2 are provided at the bottom 231D of the housing frame 231 with both ends fixed. The guide members 267B-1 and 267B-2 provided integrally with the moving plate 268B having the rack gear 267B are slidably fitted to the guide bar 269B-1, and the guide member 267B-3 is slidably fitted to the guide bar 269B-2. Match. The above is more clearly shown in FIG. 4 together with FIG. 4, which is a plan view of the paper stacking base 232 in FIG.

  In this way, the paper guide side plates 260A and 260B on both sides can be adjusted by moving in the width direction from a large size to a small size so as to have an arbitrary width dimension with respect to the center.

  However, the range in which the sheet guide side plates 260A and 260B move in this manner is such that the sheet loading side plate 232 does not come into contact with the sheet loading table 232, that is, in order not to collide with the sheet loading table 232. A part must be cut away.

  There is no problem if the small size side in the moving range is close to the B5 size, but if the moving range is further enlarged, for example, the size width of the small size is set to about a postcard size, the paper stacking base shown in the plan view of FIG. This is because the distance L between the edges 232A and 232B of 232 becomes small and becomes unstable in strength.

  In particular, the paper stacking base 232 is provided with a relief window 239 for the paper trailing edge regulating portion 250 to move when adjusting the paper size. Because of the escape window 239, the dimensions L1 and L2 that are substantially left as a table between the edges 232A and 232B become extremely short and weak.

  As a countermeasure, an auxiliary guide member 271 is provided in the present invention.

  The auxiliary guide member 271 is shown in FIGS. 1 and 2, but is easily shown in the perspective views of FIGS. In this perspective view, an auxiliary guide member 271 is attached to the sheet guide side plate 260A, FIG. 5 shows a state where the auxiliary guide member 271 is set at the guide position, and FIG. 6 shows a state where the auxiliary guide member 271 is retracted from the guide position. Show. The auxiliary guide member 271 is attached to the B-side paper guide side plate 260B with the same configuration.

  As shown in FIGS. 5 and 6, a label 274 serving as a guide for a predetermined height of the uppermost sheet is provided on each of the sheet guide side plate 260 </ b> A and the auxiliary guide member 271. This can be used for a simple check of the paper-handling situation.

  The auxiliary guide member 271 is provided with a rotation shaft 272 having the same axial center at the upper and lower portions of the paper guide side plates 260A and 260B, and is rotated 90 degrees within the normal size range so as to be retracted from the paper regulation surface. Only when feeding a small paper of a very small size smaller than the size, the paper is regulated by turning 90 degrees in the opposite direction. Further, an auxiliary guide member operation sensor 273 for detecting this switched state is provided. At this time, only the guide surface of the auxiliary guide member 271 is in a position protruding inward as compared with the guide surface 261 having a normal size range. However, since the small size paper is small in both the horizontal (width) size and the vertical size, the escape window 239 of the paper stacking base 232 does not extend in this range, so that sufficient strength can be maintained. Therefore, when feeding a very small size, the auxiliary guide member 271 can be used to achieve the purpose of width regulation without moving the guide range of the paper guide side plates 260A and 260B beyond the normal size range. it can. In addition, it is possible to realize a paper feeding device in which the paper stacking state is sufficiently stabilized without forming a narrow portion weak in strength on the paper stacking base 232.

  The positions of the paper guide side plates 260A and 260B and the auxiliary guide members 271 thus configured are set and maintained at the required regular width dimensions for each width of paper as soon as the movement adjustment for positioning is completed. It can be done as follows. That is, as shown in FIGS. 2 and 4, the elongated hole portion 284 of the scale gauge 281 of the scale gauge portion 280 attached to the paper guide side plates 260 </ b> A and 260 </ b> B is clamped to the screw hole of the fixing portion 282 integrated with the housing frame 231. This is accomplished by tightening with 283 screws.

  In this way, the regulation in the width direction from the large size to the extremely small size can be made stable in terms of mechanical structure. Further, the amount of air blown is controlled in order to blow up the uppermost sheet and separate it one by one and stably deliver the sheet to the suction sheet feeding unit 210 provided on the upper part of the base frame 201. Is preferred. This will be described in detail below.

  FIG. 7 is a perspective view showing the inside of the sheet guide side plate 260A with the back cover removed. FIG. 8 is a perspective view showing the inside of the sheet guide side plate 260A in a state where the restriction surface 261 is removed.

  As shown in FIGS. 7 and 8, the paper guide side plates 260 </ b> A and 260 </ b> B are respectively connected to a blower 263 that is directly connected to a DC motor (not shown), an air suction port 262 to the blower 263, and the air suction. A duct 265 that forms an air path from the mouth 262 to the air outlet 264 and a shutter 266 that opens and closes the air inlet 262 are incorporated.

  Air is blown every time a sheet is supplied, and when air is blown and the sheet is sucked by the suction belt 212 and the conveyance of the sheet is started, the air is short until the next sheet feeding is performed. The air is blocked by the shutter 266 for the time, and the timing of feeding each sheet is stabilized. In addition, there are no gaps or obstacles to double feeding between the preceding paper. This achieves a stable high speed of paper feeding. Since it is impossible to adjust the air volume in a short time by stopping the motor for each paper feeding cycle, the means as in this embodiment is adopted.

  As shown in FIG. 1, the upper surface of the air outlet 264 is higher than a predetermined height at which the uppermost sheet of the sheet stacking base 232 is detected and held by the sensor 241, and the lowermost surface of the suction sheet feeding unit 210. Is set lower than the lower surface of the suction belt 212 corresponding to. The lower surface of the air outlet 264 is set lower than the predetermined height. As a result, the uppermost sheet can be reliably made and easily separated.

  In this embodiment, the amount of air blown is controlled by changing the rotational speed of the DC motor directly connected to the blower 263 in the paper guide side plates 260A and 260B in accordance with the combination of the paper type and the amount of dredging. Done.

  Similarly, a sheet at a predetermined height at the uppermost portion is blown obliquely upward inside the sheet leading edge positioning unit 240 and dammed so that the sheet does not flow downstream from the sheet leading edge positioning unit 240. . An air blowing blower 242 that transfers the leading end of the uppermost sheet to the suction sheet feeding unit 210 and assists in separating one sheet is directly connected to the DC motor. The blow-up amount of the air blow-off port 243 is also controlled by changing the rotational speed of the DC motor according to the combination of the paper type and the amount of soot. However, in this case, the air suction port of the blower 242 is not opened / closed every time one sheet is supplied, and is continuously blown out.

  In this way, by blowing air from the air blowing port 243 and the air blowing port 264, a single sheet separating unit for separating one uppermost sheet stacked on the sheet stacking base 232 is formed.

  In the present invention, first, each DC motor directly connected to each of the blowers 242 and 263 for obtaining an optimum air volume for separating one sheet of the uppermost sheet on the sheet stacking base, which is large in the amount of paper and common to each sheet type. The rotation speed of is determined experimentally and determined as the maximum rotation speed. In addition, the rotational speeds of the blowers 242 and 263 for obtaining the optimum air volume for separating the uppermost sheet on the sheet stacking table are experimentally determined for each combination of sheet types and sheet amounts. The rotation speed was obtained and expressed as a percentage of the maximum rotation speed. The obtained data can be used as it is as data information to optimize the separation of one sheet. That is, from the data in this experimental result, it was found that stable paper feeding can be performed by setting the optimum air volume corresponding to the combination of each paper type and each hull amount. In addition, the size range can be simplified as follows.

  First, as a first group, Table 1 shows what is obtained as an optimum value data table by applying it to a sheet in a normal size range in which the minimum size is a width dimension of about B5 size. Accordingly, it is possible to stably and optimally feed a normal size sheet within a range (B5 horizontal to A3 vertical) regulated by the regulation surfaces 261 of the paper guide side plates 260A and 260B.

  On the other hand, as a second group, the auxiliary guide member 271 is moved 90 around the rotation shaft 272 for a small paper of a very small size (less than B5 size to a postcard of various sizes) in a range less than the normal size. Rotate and set to the operating position, and the air volume of each of the blowers 242 and 263 is switched as follows by the detection of the auxiliary guide member operating sensor 273. Also at this time, the maximum rotational speed of each DC motor directly connected to each of the blowers 242 and 263 is set through experiments as described above. The optimum rotational speed of each blower for the separation of the uppermost sheet on the paper stacking table, which is a combination of each paper type and each weight with respect to the maximum rotational speed, is an optimum value expressed as a percentage of the maximum rotational speed. Table 2 shows the data table obtained. As a result, even when the auxiliary guide member 271 is actuated to regulate the width and the paper size is smaller than the normal size and includes the postcard size, the optimum air volume corresponding to the combination of each paper type and each hull amount is the size. It was confirmed that stable and optimal paper feeding was possible in common for all sizes within the range.

The vertical positions in Tables 1 and 2 indicate the paper types classified as coated paper, reprint paper, plain paper / quality paper, book paper / rough paper, and horizontal positions indicate weight (also referred to as basis weight g / m ² ). As described above, the direct current motor that directly connects the air blowing amount from the leading edge positioning unit and the air blowing amount from the paper guide side plate to each blower as the optimum air volume when feeding the paper combining the above vertical and horizontal conditions. Is expressed as a ratio to the maximum rotation speed. If, for example, 20/50 is displayed, 20 represents the percentage of the maximum rotational speed of the blower 242 and 50 represents the percentage of the maximum rotational speed of the blower 263.

  Here, in Tables 1 and 2, it was found that the maximum rotational speed of each motor directly connected to each blower 242, 263 may be the same value experimentally. The maximum rotation speed was set to 2000 rpm at low humidity, 2300 rpm at normal humidity, and 2500 rpm at high humidity as the maximum rotation speed at 100% output of the DC motor in consideration of changes in the load determined by the atmosphere due to temperature and humidity. . Each maximum rotation speed and each optimum rotation speed experimentally confirmed are changed by a pulse width modulation method (PWM method) to obtain an optimum value. Each optimum rotation speed is a percentage of each maximum rotation speed. it's shown. Here, the method of changing the rotation speed may be a method of changing the voltage of the DC motor.

  FIG. 9 is a block diagram of a control system for the above-described air volume control of the sheet feeding device 200.

  A CPU (Central Processing Unit) 701 is connected to a ROM (Read Only Memory) 702, a RAM (Random Access Memory) 703, an operation display unit 705, and the like via a system bus 707. The CPU 701 reads out the first group data table T1 as shown in Table 1 or the second group data table T2 as shown in Table 2 from the various programs stored in the ROM 702. And expanded in the RAM 703. Then, the paper size area switched by the ON / OFF signal of the auxiliary guide member sensor 263 and the amount of paper and the paper type input to the operation display unit 705 are collated with the data table T1 and the data table T2, and the blowing port 243 The air volume at the outlet 264 is selected. Then, the command of the selected air volume is issued to the blower 242 and the blower 263, and each optimum rotation speed is controlled by the rotation of each motor directly connected as% of the maximum rotation speed.

  The CPU 701 executes various processes according to the program developed in the RAM 703, stores the processing results in the RAM 703 and causes the operation display unit 705 to display them. Then, the processing result stored in the RAM 703 is stored in a predetermined storage destination. In the present embodiment, the CPU 701 cooperates with the ROM 702 and the RAM 703 to constitute the main part of the control device 700.

FIG. 3 is a front cross-sectional view showing an internal configuration in a state where an example of a large-capacity paper feeding device of the present invention is connected to an image forming apparatus incorporating a small-capacity paper feeding cassette. FIG. 4 is a plan view of a paper stacking tray mounted on the paper feeding device of the present invention. (A) is a rear view showing the wire winding state on the A side of the paper stacking tray mounted on the paper feeding device of the present invention, and (b) is a front view showing the wire winding state on the B side. . FIG. 3 is a plan view showing a state where a paper stacking base is removed in FIG. 2. FIG. 6 is a perspective view of a sheet guide side plate showing a state where an auxiliary guide member is set at a guide position. FIG. 6 is a perspective view of a sheet guide side plate in a state where an auxiliary guide member is retracted from a guide position. FIG. 6 is a perspective view showing the inside of the paper guide side plate with the cover on the back surface removed. FIG. 6 is a perspective view showing the inside of the sheet guide side plate in a state where a restriction surface is removed. FIG. 6 is a block diagram of an air volume control system of a paper feeding device.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Image forming apparatus 200 Paper feeding apparatus 201 Base frame 210 Suction feeding part 220 Paper conveyance part 230 Paper stacking tray 230-1 Handle 231 Housing 232 Paper stacking bases 233A-1, 233A-2, 233B-1, 233B- 2 Wires 234A-1, 234A-2, 234B-1, 234B-2 Pulley 235A, 235B Take-up pulley 236 Drive unit 239 Relief window 240 Paper leading edge positioning portion 241 Sensor 242, 263 Blower 242a, 263a DC motor 243 Air blow-up port 250 Paper rear end restricting portion 260A, 260B Paper guide side plate 261 Restricting surface 262 Air suction port 264 Air blowing port 265 Duct 266 Shutter 267 Pinion gear 267A, 267B Rack gear 267A-1, 267A-2 267A-3, 267B-1, 267B-2, 267B-3 Guide member 268A, 268B Moving plate 269A-1, 269A-2, 269B-1, 269B-2 Guide bar 271 Auxiliary guide member 272 Rotating shaft 273 Auxiliary guide Member operation sensor 280 Scale gauge part 281 Scale gauge 282 Fixed part 283 Clamper 284 Long hole part 700 Control device

Claims (8)

A paper stacking table having a mechanism for loading paper and driving the uppermost paper so as to have a predetermined height;
A paper guide side plate disposed so as to be movable so as to regulate the position in the width direction of the paper stacked on the paper stacking base to a predetermined position;
A paper leading edge positioning portion that regulates a leading edge position of the paper loaded on the paper stacking table;
A paper trailing edge restricting portion for restricting a trailing edge position of the paper loaded on the paper loading table;
One sheet separation for separating the uppermost sheets stacked on the sheet stacking table one by one by blowing air from an air blowing opening provided on the sheet guide side plate and an air blowing opening provided on the sheet leading edge positioning unit. Means,
A paper stacking tray having
A paper feeding / conveying means provided on an upper part of the paper stacking tray for receiving the paper separated by the single sheet separating means and conveying it to the next process;
An auxiliary guide member for regulating a sheet having a width smaller than the minimum width of the sheet regulated by the sheet guide side plate;
A paper feeding device comprising: 2. The sheet feeding device according to claim 1, wherein the sheet feeding / conveying unit includes a suction sheet feeding unit that receives the sheet separated by the single sheet separating unit and a sheet conveying unit. An upper surface of the air outlet is set higher than the predetermined height and lower than a lowermost surface of the suction paper feeding unit, and a lower surface of the air outlet is set lower than the predetermined height. The sheet feeding device according to claim 1 or 2. The air volume of the air outlet and the air blow-up outlet are compared with data information predetermined for each paper size corresponding to the combination of the paper type and paper amount of the paper to be fed. The paper feeding device according to claim 1, wherein the paper feeding device is selected. When the width of the paper is regulated by the paper guide side plate and when the width is regulated by switching to the auxiliary guide member, the data information is a first size data table for the normal size and a small size data table, respectively. 5. The sheet feeding device according to claim 4, wherein the sheet feeding device is used after being sorted into a second group of data tables. The air volume of the air blowout port and the air blowout port can be varied by changing the rotational speed of the DC motor using a pulse width modulation method for a DC motor that drives the blower. Item 6. The paper feeding device according to Item 4 or 5. The sheet feeding device according to any one of claims 1 to 6, wherein the sheet stacking tray can be pulled out from a base frame of the sheet feeding device. An image forming apparatus comprising the sheet feeding device according to claim 1.

Images