JP4127210B2 - Paper feeding device, large capacity paper feeding device, and image forming apparatus system - Google Patents

Description

  The present invention relates to a sheet feeding device capable of stacking sheets of different sizes, a large capacity sheet feeding device including the sheet feeding device, and an image forming apparatus system including the large capacity sheet feeding device.

  2. Description of the Related Art Image forming apparatuses such as copying machines and printers are provided with a paper feed cassette that stacks and feeds a plurality of sheets for image formation. In addition, when there are a large number of sheets for image formation, for example, 1000 sheets or more, a large capacity sheet feeding device (LCT) capable of stacking such a large number of sheets is connected to the side of the image forming apparatus. Paper is fed from the large capacity paper feeder to the image forming apparatus.

  On the other hand, paper of different sizes can be stacked on the paper feed cassette or the large capacity paper feeder, and a guide configured to be movable is provided so that different sizes of paper can be set at regular positions. In the paper feeding direction, the leading edge of the paper is in contact with a fixing member such as the inner wall of a paper feeding cassette or a large-capacity paper feeding device, and the trailing edge is provided with a trailing edge guide movable in the feeding direction. . Also, in the width direction orthogonal to the paper feeding direction, side guides that restrict both side edges of the paper are provided, and when one side guide is moved, the other side guide is linked in the reverse direction. The center position does not change even for papers having different widths.

  In other words, the rear end guide and the side guide are erected so as to be movable in the horizontal direction on the sheet stacking section for stacking sheets, and position control is performed on the range from the lowermost surface to the uppermost surface of the sheet.

  Here, among the plurality of stacked sheets, the uppermost sheet is configured to be held at a substantially constant height, and the uppermost sheet is fed by the feed roller and separated. The paper is separated into one sheet by a pair of paper rollers and fed by a pair of transport rollers. At this time, a rear end guide is provided in order to prevent the sheet from being retracted by the separating and separating roller pair and becoming unable to feed paper. The same applies to the influence of air assist for ensuring separation of the paper. As described above, the regulation of the trailing edge of the sheet by the trailing edge guide is important, and the trailing edge guide is configured so that its position can be changed according to the size of different sheets by a slide method or a replacement method.

As an example of the rear end guide for changing the position as described above, an invention has been disclosed in which an arm that expands and contracts is connected to the rear end guide so that paper of an arbitrary size can be set (see Patent Document 1).
JP 2002-46869 A

  Since the conventional rear end guide is provided in the paper stacking section for stacking paper, even if the thickness of the loaded paper becomes very thick in the large-capacity paper feeder or paper cassette, it reaches the top surface. It was long and formed so that it could be regulated. For this reason, the size has been increased in order to guarantee the strength.

  In addition, when the user sets a different size of paper, the rear end guide is operated to change the position, so that the operation is troublesome, and if there is an operation mistake, paper feeding may become impossible.

  The present invention has been made in view of such a problem, and the length of the trailing edge guide is short, and the trailing edge guide automatically regulates the trailing edge of the sheet according to the set sheet. It is an object of the present invention to provide a sheet feeding apparatus configured as described above, a large capacity sheet feeding apparatus including the sheet feeding apparatus, and an image forming apparatus system including the large capacity sheet feeding apparatus.

  The above object is achieved by the following means.

In a paper feeding device having a paper stacking unit capable of stacking sheets of different sizes and a paper feeding unit that feeds the papers stacked on the top surface one by one, the trailing edge of the paper in the paper feeding direction is The rear end guides to be regulated are positioned above the paper stacking portion so as to be movable in the vertical direction, and a plurality of rear end guides provided in the paper feeding direction and hung down by their own weight are used as the rear end of the predetermined paper. The rear end guide located on the side of the paper feed unit with respect to the predetermined rear end guide is pressed by the paper located on the uppermost surface and moves upward , and the rear end guide At least one detection unit that detects a moving state is provided, and a detection unit that detects a length of the paper in the paper feeding direction from the detection unit is provided .

According to the sheet feeding device, the large-capacity sheet feeding device, and the image forming apparatus system of the present invention, the length of the trailing edge guide can be shortened, and the trailing edge guide is automatically set according to the set sheet. Since the rear end portion is regulated, there is an effect that the paper feeding is not disabled due to an operation error by the user. In addition, since at least one detection unit for detecting the movement state of the trailing edge guide is provided and detection means for detecting the length of the paper in the paper feeding direction is provided by the detection unit, the size of the loaded paper is detected. The paper size information can be sent to the image forming apparatus.

  Hereinafter, embodiments of the paper feeding device of the present invention will be described with reference to the drawings.

  First, a configuration of an image forming apparatus system including an image forming apparatus provided with a paper feeding device and a large capacity paper feeding device will be described with reference to FIG.

  The image forming apparatus A is called a tandem type color image forming apparatus, and includes a plurality of sets of image forming units 10Y, 10M, 10C, and 10K, a belt-like intermediate transfer member 6, a paper feeding device 20, a fixing device 30, and the like. Consists of.

  On the upper part of the image forming apparatus A, an image reading apparatus B is installed. The document placed on the document table is scanned and exposed by the optical system of the document image scanning exposure apparatus of the image reading apparatus B, and read by the line image sensor. The analog signal photoelectrically converted by the line image sensor is subjected to analog processing, A / D conversion, shading correction, image compression processing, and the like in the image processing unit, and then input to the exposure means 3Y, 3M, 3C, 3K. The

  The image forming unit 10Y that forms a yellow (Y) image includes a charging unit 2Y, an exposure unit 3Y, a developing device 4Y, and a cleaning unit 5Y disposed around a photosensitive drum 1Y as an image carrier. The image forming unit 10M that forms a magenta (M) color image includes a photosensitive drum 1M as an image carrier, a charging unit 2M, an exposure unit 3M, a developing device 4M, and a cleaning unit 5M. An image forming unit 10C for forming a cyan (C) color image includes a photosensitive drum 1C as an image carrier, a charging unit 2C, an exposure unit 3C, a developing device 4C, and a cleaning unit 5C. The image forming unit 10K that forms a black (K) image includes a photosensitive drum 1K as an image carrier, a charging unit 2K, an exposure unit 3K, a developing device 4K, and a cleaning unit 5K. The charging unit 2Y and the exposure unit 3Y, the charging unit 2M and the exposure unit 3M, the charging unit 2C and the exposure unit 3C, and the charging unit 2K and the exposure unit 3K constitute a latent image forming unit.

  The developing devices 4Y, 4M, 4C, and 4K include a two-component developer including yellow (Y), magenta (M), cyan (C), and black (K) small particle size toners and a carrier.

  The intermediate transfer body 6 is wound around a plurality of rollers and is rotatably supported.

  The respective color images formed by the image forming units 10Y, 10M, 10C, and 10K are sequentially transferred (primary transfer) by the primary transfer units 7Y, 7M, 7C, and 7K onto the rotating intermediate transfer body 6, and a color image is formed. Synthesized.

  The paper S accommodated in the paper feeding cassette 21A of the paper feeding device 20 is fed by the paper feeding means 22A and conveyed to the transfer roller 9 through the paper feeding rollers 23, 24, 25, 26, the registration rollers 27, and the like. Then, the color image is transferred (secondary transfer) onto the paper S.

  Note that the three-stage sheet feeding cassettes 21A arranged vertically in the vertical direction below the image forming apparatus A have substantially the same configuration, and thus are given the same reference numerals. Further, the three-stage sheet feeding means 22A has the same configuration and is therefore given the same reference numeral.

  Further, the sheet feeding device 21 including the sheet feeding cassette 21A and the sheet feeding unit 22A is referred to as a sheet feeding device 20.

  The sheet S on which the color image is transferred is sandwiched between the heating roller 30A and the pressure roller 30B in the fixing device 30, and heated and applied. As a result, the toner image on the paper S is fixed and fixed on the paper S, and is sandwiched between the paper discharge rollers 28 and placed on the paper discharge tray 29 outside the apparatus.

  On the other hand, after the color image is transferred onto the paper S by the transfer roller 9, the residual toner is removed by the cleaning unit 8 from the intermediate transfer body 6 that has separated the curvature of the paper S.

  In the case of reversely discharging the fixed sheet S, the sheet S passes through the lower conveyance path of the branch plate 28A disposed between the fixing device 30 and the sheet discharge roller 28, and the lower conveyance path r1. Then, the sheet is conveyed in the reverse direction, passes through the conveying path r2 on the left side of the branch plate 28A, and is discharged out of the apparatus by the paper discharge roller 28.

  When copying on both sides of the sheet S, after fixing the image formed on the first surface of the sheet S, the sheet S is introduced into the transport path r1 and further into the transport path r3, then transported in reverse, and transported path r4. Then, the sheet is detoured upward and conveyed by the paper feed roller 26. In the same manner as described above, the sheet S is formed with an image of each color on the second surface which is the back surface of the first surface, heated and fixed by the fixing device 30, and discharged to the outside by the discharge roller 28.

  The image forming apparatus A is provided with a manual sheet feeding device C. The paper S accommodated in the manual paper feed tray 21B of the manual paper feed device C is fed by the paper feed means 22B, sent to the transfer roller 9 through the paper feed rollers 25 and 26 and the registration roller 27, and Similarly, an image is formed.

  The image forming apparatus A described above is an image forming apparatus that forms a color image, but may be an image forming apparatus that forms a monochrome image.

  On the right side of the image forming apparatus A in the figure, a large-capacity large-capacity sheet feeding device LT for feeding a large amount of sheets of, for example, 1000 sheets or more is connected. Based on the large-capacity paper feeder LT, the paper feeder according to the present invention will be described.

  The large-capacity paper feeding device LT includes a main body 40 that stores the paper S, and a lid portion 50 that is configured to be openable and closable with respect to the main body 40 when the paper S is stored. The main body 40 is provided with a paper stacking portion 41, a paper feeding portion including a feeding roller 42, a separating roller pair 43, and a conveying roller pair 44, and the lid portion 50 has a plurality of rear end guides 60 (61-67). Is provided.

  The sheet S is stacked on the sheet stacking unit 41. When the cover unit 50 is opened, the sheet stacking unit 41 is positioned below. When the sheet S is stacked and the cover unit 50 is closed, the sheet stacking unit 41 is not illustrated. Driven by the motor and ascend. Then, when the sensor (not shown) detects the sheet S positioned on the uppermost surface, the ascent of the sheet stacking unit 41 is stopped.

  When a paper feed signal for feeding paper from the large-capacity paper feeder LT is output from the image forming apparatus A to the large-capacity paper feeder LT, the feed roller 42 pressed against the paper S positioned on the uppermost surface rotates, The sheet is separated into one sheet by the separating roller pair 43 and fed into the image forming apparatus A by the conveying roller pair 44.

  The large-capacity paper feeder LT can store paper of different sizes. In the paper feeding direction of the paper S, the leading edge of the paper S abuts against a fixing member in the main body 40, and the trailing edge is regulated by the trailing edge guide 60 according to the present invention. The rear end guide 60 will be described later in detail. Further, in the width direction orthogonal to the paper feeding direction of the paper S, side guides (not shown) that restrict both side ends of the paper S are provided in the main body 40, and when one side guide is moved, the other side guide is moved. The side guide is interlocked and moved in the opposite direction, so that the center position does not change even for sheets of different widths. In addition, what is necessary is just to use this well-known and common side guide.

  Here, a plurality of rear end guides 60 (61 to 67) will be described with reference to FIG. In FIG. 2, only the rear end guides 62 to 64 that are part of the rear end guide 60 are illustrated, but the other rear end guides 60 have the same configuration. Each rear end guide 60 has two long holes (62A to 64A in FIG. 2), and two guide shafts 51 pass through the two long holes, and each rear end guide 60 extends in the vertical direction. It is arranged to move freely. Further, both ends of the two guide shafts 51 are held by holding plates 52 that hang down from the back surface of the lid 50. Note that the rear end guide 60 is regulated in the feeding direction of the paper S by a member (not shown) suspended from the back surface of the lid 50 and does not move in the axial direction of the guide shaft 51.

  The position of each trailing edge guide 60 is determined in advance, and the surface on which the sheet S is fed, that is, the left surface in FIGS. It is placed in a possible position. For example, it is assumed that sheets S having sizes A3, B4, A4, A4R, B5, B5R, A5R, and B6R can be stacked on the sheet stacking unit 41. Then, the lengths of the leading edge and the trailing edge of each sheet S in the sheet feeding direction are 420 mm, 364 mm, 210 mm, 297 mm, 182 mm, 267 mm, 210 mm, and 128 mm, respectively. Accordingly, the rear end guide 61 in FIG. 1 is for B6R, the rear end guide 62 is for B5, the rear end guide 63 is for A5R and A4, the rear end guide 64 is for B5R, the rear end guide 65 is for A4R, and the rear end. The guide 66 is for B4, and the rear end guide 67 is for A3.

  When the sheet S is not stacked on the sheet stacking unit 41, the respective rear end guides 60 (61 to 67) are suspended downward by their own weight.

  On the other hand, when the paper S is stacked on the paper stacking unit 41, the paper stacking unit 41 is raised by driving a motor (not shown), and a sensor (not shown) detects the paper S located on the top surface, so that The positioned sheet S has a substantially constant height, and the lifting of the sheet stacking unit 41 stops. At this time, the rear end guide 60 positioned above the sheet S is pressed by the sheet S positioned on the uppermost surface and pushed upward.

  For example, in FIGS. 1 and 2, it is assumed that the stacked sheets S are A4 size. Then, since the rear end guide 60 positioned above the sheet S is the rear end guides 61 and 62, only the rear end guides 61 and 62 are pressed and pushed up by the sheet S positioned on the uppermost surface, and the other rear ends. The guides 63 to 67 maintain a state where they are suspended by their own weight. At this time, the rear end portion of the sheet S is regulated by the rear end guide 63. Therefore, the sheet S is prevented from moving backward by the separating and separating roller pair 43 and the like, so that it is possible to avoid paper feeding from being disabled.

  As a matter of course, such an operation can be applied from, for example, a minimum size B6R sheet to a maximum size A3 sheet.

  Each rear end guide 60 is preferably formed of a material having a low frictional resistance so as not to interfere with the sheet feeding operation of the sheet S, so that the area in contact with the sheet S is small. It is desirable.

  A plurality of detection units 70 (photo sensors and the like) are provided corresponding to each rear end guide 60. Then, it is detected whether each of the rear end guides 60 is suspended or pushed upward. For example, if the loaded paper S is A4, the rear end guides 61 and 62 are pushed up as described above, and this is detected by the detection unit 70 for the rear end guides 61 and 62 (such as the detection unit 72 in FIG. 2). It is possible to detect that the sheet S that has been detected and loaded is A4 size by a detection unit (not shown) such as a CPU, and send information on the sheet size to the image forming apparatus A.

  Further, in this case, the dedicated detection unit 70 (detection units 73, 74, etc. in FIG. 2) detects that the rear end guides 63 to 67 are suspended, and determines that the stacked paper S is A4 size. Alternatively, the adjacent trailing edge guides 62 are pushed up and the trailing edge guide 63 is suspended by the dedicated detection unit 70 (detection units 72 and 73 in FIG. 2). S may be determined to be A4 size.

  Note that if the size of the paper S stored in the large-capacity paper feeder LT is limited to A4 and A3, for example, only the detection unit 73 that detects the movement of the rear end guide 63 is sufficient.

  On the other hand, in the above description, the rear end guide 60 is pressed from below by the sheet S positioned on the uppermost surface and moved upward. However, the pressing direction is not necessarily limited to this. You may make it the structure which presses from a side and moves it upwards. An example of this is shown in FIG.

  In FIG. 3, the paper S sufficiently stacked on the paper stacking portion moves from the left, contacts the lower left arc portion 60 </ b> C of the rear end guide 60, pushes up the rear end guide 60, and then the paper. S is positioned at a predetermined position below the rear end guide 60. This configuration can be applied to, for example, the paper feeding cassette 21A of the paper feeding device 20 in the image forming apparatus A. The rear end guide 60 is disposed above the insertion opening for inserting the paper feeding cassette 21A, and the paper S is sufficiently drawn out. If the loaded paper cassette 21A is inserted from the front (or from the side), the above-described operation is performed.

1 is a configuration diagram of an image forming apparatus system including an image forming apparatus and a large-capacity paper feeding apparatus. It is a perspective view of a rear end guide. It is a figure pressed from the side of a rear end guide with paper.

Explanation of symbols

A Image forming apparatus LT Large-capacity paper feeder S Paper 40 Main body 41 Paper stacking part 42 Feeding roller 50 Cover part 60, 61, 62, 63, 64, 65, 66, 67 Rear end guide 70, 72, 73, 74 Detection Part

Claims (3)

In a paper feeding device including a paper stacking unit capable of stacking different sizes of paper and a paper feeding unit that feeds paper stacked on the top surface one by one,
A rear end guide that regulates the rear end of the paper in the paper feeding direction is positioned above the paper stacking portion so as to be movable in the vertical direction, and a plurality of rear end guides are provided in the paper feeding direction.
A predetermined trailing edge guide hanging under its own weight regulates the trailing edge of a predetermined sheet,
A rear end guide located closer to the paper feed unit than the predetermined rear end guide is pressed by the paper located on the uppermost surface and moves upward , and
At least one detection unit that detects the movement state of the rear end guide is provided, and a detection unit that detects the length of the paper in the paper supply direction is provided by the detection unit . A large-capacity paper feeding device comprising the paper feeding device according to claim 1. 3. An image forming apparatus system comprising: the large capacity sheet feeding apparatus according to claim 2 and an image forming apparatus that forms an image of a sheet fed from the large capacity sheet feeding apparatus.

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