JP2008050118A - Paper feeder and image forming device having it - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To accurately detect the uppermost recording material in the bundle of the supplemented recording material even when the bundle of the supplemented recording material is displaced from the distal end side reference surface in the paper feeding direction or even when the bundle of the supplemented recording material causes warpage. <P>SOLUTION: (1) When first and second supplementing height detection means 35, 36 detect the supplement of the recording material S after a detection signal from an opening/closing detection sensor 34 is inputted, a paper feed table drive means 14 is operated to lower a paper feed table 3 until the first and second supplementing height detection means 35, 36 detect the height of the uppermost paper S on the paper feed table 3. (2) When a first supplementing height detection means 34 or a second supplementing height detection means 36 detects the supplement of the recording material S, one of the first and second supplementing height detection means 35, 36 which detects the supplement of the recording material S lowers the paper feed table 3 by operating the paper feed table drive means 14 until it detects the height of the uppermost paper (recording material S) on the paper feed table 3. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a sheet feeding device configured to feed sheet-like recording materials such as copy sheets and OHP films stacked on a sheet feeding table one by one from the sheet feeding table, and to be fed from the sheet feeding device. The present invention relates to an image forming apparatus (such as a copying machine, a printer, a facsimile machine, and a multi-function machine of these) that prints an image on a recorded material.

  Conventionally, as shown in FIG. 8, in order to enable a large amount of printing, a large capacity sheet feeding device 101 is provided in the image forming apparatus main body 102 or a large capacity sheet feeding device 103 is provided in the image forming apparatus main body. An image forming apparatus 100 that can be detachably installed outside 102 is used.

  In such an image forming apparatus 100, when the large capacity sheet feeding apparatuses 101 and 103 send out the recording material S to the image forming unit 104, the sheet feeding base 105 is raised at a predetermined timing to perform recording with the sheet feeding unit 106. The height position (paper feed height position) of the paper feed tray 105 is adjusted so that the contact state of the material S becomes a state that enables stable paper feeding.

  Further, in the case of supplying the recording material S, the large-capacity paper feeding devices 101 and 103 as shown in FIG. 8 output a recording material replenishing operation start signal when opening the lid or pulling out the paper feeding tray. It is input to a controller (not shown) of the forming apparatus 100, and an operation control signal is output from the controller to the driving means of the paper feeding apparatuses 101 and 103. Then, as shown in FIGS. 8 and 9A, the sheet feeding apparatuses 101 and 103 are configured such that the sheet feeding table 105 is lowered to a predetermined height (from the sheet feeding position h1 to the replenishment height position h2. When the sensor 110 attached to the sheet feeding device main body 108 (107) detects the uppermost recording material S stacked on the sheet feeding table 105, the sheet feeding table 105 stops at its height position and is replenished. It will be in a standby state (refer patent document 1).

JP 2004-83206 A

  However, in such a conventional sheet feeding device 103 (101), for example, as shown in FIG. 9B, a bundle of the replenished recording materials S has a predetermined dimension from the reference surface 111 in the sheet feeding direction (side). d1) When the recording material S is placed with a deviation, the tip of the sensor 111 cannot touch the tip of the bundle of recording materials S (missing), and the sensor 111 detects that the recording material S has been replenished. There was a possibility that the desired replenishment operation could not be performed.

  Further, as shown in FIG. 9C, when the bundle of supplied recording materials S is warped, the tip of the sensor 111 cannot touch the tip of the bundle of recording materials S. (Swivel), the sensor 111 cannot detect that the recording material S has been replenished, and the desired replenishment operation may not be performed.

  Accordingly, the present invention provides a recording medium that has been replenished even when the replenished recording material bundle is deviated from the reference surface in the sheet feeding direction or when the replenished recording material bundle is warped. An object of the present invention is to make it possible to accurately detect the uppermost recording material of a bundle of materials and to perform a desired replenishment operation.

  The sheet feeding device according to the first aspect of the present invention includes (1) a sheet feeding table that can be raised and lowered, and (2) a sheet feeding unit that feeds sheet-like recording material on the sheet feeding table one by one from the sheet feeding table. And (3) a sheet feeding table driving means for moving the sheet feeding table up and down, and (4) a replenishment operation for detecting that an operation for replenishing a large number of the recording materials on the sheet feeding table is started. And (5) detecting the height position of the recording material positioned at the top of the multiple recording materials supplied on the paper feed base at the leading end side in the feeding direction of the recording material. A first replenishment height detecting means; and (6) a height position of the recording material positioned at the top of the plurality of recording materials replenished on the paper feed table, A second replenishment height detecting means for detecting on the side surface orthogonal to the direction; and (7) the replenishment operation detecting means and the first replenishment height. It comprises a control means for controlling operation of the feed table drive means based on knowledge means and the detection signal from the second supply when the height detecting means. In this sheet feeding apparatus, the control unit is (1) the first replenishment height detection unit and the second replenishment height detection unit after the detection signal from the replenishment operation detection unit is input. When the replenishment of the recording material is detected, the first replenishment height detection means and the second replenishment height detection means detect the height position of the recording material located on the uppermost position on the paper feed table. The sheet feeding table driving means is operated until the sheet feeding table is lowered or (2) or after the detection signal from the replenishment operation detecting means is input, the first replenishment height detecting means Alternatively, when the second replenishment height detection means detects the replenishment of the recording material, the replenishment of the recording material is detected in the first replenishment height detection means or the second replenishment height detection means. The height of the recording material positioned at the top of the sheet feed table. Lowering the feed table by operating the feed table drive means until the knowledge, it is characterized in that.

  According to a second aspect of the present invention, in the paper feeding device according to the first aspect of the invention, (1) the recording material in a direction orthogonal to the feeding direction of the recording material is set to the first replenishment height detecting means. (2) The second replenishment height detecting means is arranged at the central portion on the side surface of the recording material in the direction along the feeding direction of the recording material. Yes.

  According to a third aspect of the present invention, in the paper feeding device according to the first aspect of the present invention, (1) the first replenishment height detecting means is set to the recording material in a direction orthogonal to the feeding direction of the recording material. (2) the second replenishment height detecting means is 60 mm from the central portion on the side surface side of the recording material in the direction along the feeding direction of the recording material. It is characterized by being arranged within the range up to.

  According to a fourth aspect of the present invention, there is provided a paper feeding device according to any one of the first to third aspects, and an image forming unit that prints an image on a recording material fed from the paper feeding device. And an image forming apparatus.

  According to the present invention, the replenished recording material does not warp and is placed at the correct position on the paper feed table, as well as the front end of the replenished recording material in the paper feed direction. Even if the plate (developed in the paper feeding direction) is displaced without being abutted, or even if the supplied recording material is warped, the highest level of the supplied recording material is recorded. The material can be detected accurately, and the desired replenishment operation of the recording material can be performed accurately and smoothly.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

(Constitution)
FIG. 1 is a diagram illustrating an image forming apparatus 1 according to the present embodiment and a sheet feeding device 2 used in combination with the image forming apparatus 1.

  As shown in FIG. 1, a sheet feeding device 2 that enables large-volume sheet feeding is assembled to the side surface side (right side surface in FIG. 1) of the image forming apparatus 1 in a detachable state.

  The sheet feeding device 2 is configured to be able to stack a large capacity (thousands) of recording materials (sheet-like copy paper, plastic film, etc.) S on a sheet feeding table 3 that can be moved up and down. The means 4 feeds the uppermost recording material S on the paper feed tray 3 one by one to the image forming apparatus 1 side.

  In the image forming apparatus 1, a sheet feeding port 7 that allows the recording material S to pass therethrough is formed on the right side surface 6 of the image forming apparatus main body 5, and the recording material S fed from the sheet feeding device 2 is fed to the sheet feeding port. 7 into the image forming apparatus main body 5. In this image forming apparatus 1, the recording material S taken from the paper feed port 7 is transported along the transport path 11 to the image forming unit 12 by the transport roller pair 8 and 10, and the recording material S is transferred to the recording material S by the image forming unit 12. An image is printed, and the printed recording material S is sent out to a discharge tray or a post-processing device (a device capable of performing stapling, sorting, punching, bookbinding, etc.) not shown. . The image forming unit 12 only needs to be able to print on the sheet-like recording material S. For example, an electrophotographic image forming unit or an inkjet image forming unit can be considered, but the image forming unit 12 is not limited thereto. Absent. Further, the recording material S on the paper feed tray 3 is positioned by positioning guide members (not shown) at both ends in the width direction orthogonal to the paper feed direction.

  In FIG. 1, the sheet feeding device 2 guides the movement of the sheet feeding table 3 by a guide (not shown) in the sheet feeding device body 13, and the sheet feeding table 3 is moved up and down by the sheet feeding table driving means 14. It is like that. The sheet feed table drive means 14 includes a motor 15, a drive pulley 16 that is rotationally driven by the motor 15, and a first driven pulley that is rotatably mounted above the sheet feed position h1 in the sheet feeder main body 13. 17, a second driven pulley 18 that is rotatably attached to the sheet feed table 3, and a drive pulley 16 and a wire 20 that is stretched over the first and second driven pulleys 17 and 18. Among these, the motor 15 and the drive pulley 16 are attached to the lower part in the sheet feeder main body 13. Further, one end of the wire 20 is fixed to a support portion 21 arranged at the same height position as the first driven pulley 17 in the sheet feeding device body 13, and the other end is attached to the drive pulley 16 so that it can be wound up. The intermediate portion is stretched over the first driven pulley 17 and the second driven pulley 18. The sheet feeding table driving means 14 configured as described above drives the sheet feeding table 3 to move up and rotate by the motor 15 when the drive pulley 16 that is driven to rotate by the motor 15 winds up the wire 20. When the pulley 16 sends out the wire 20 (rewinds), the paper feed table 3 is moved downward.

  Further, in FIG. 1, a recording material detection sensor 22 that detects the presence or absence of the recording material S is installed in the paper feed table 3. When the recording material detection signal of the recording material detection sensor 22 is input to the control unit 23, display data is output from the control unit 23 to the display unit 50, and characters or characters for prompting the display unit 50 to replenish the recording material are displayed. A graphic or the like is displayed or a replenishment lamp is turned on. In addition, a sheet feed table bottom position detection sensor 24 that detects the lowest position of the sheet feed table 3 is installed in the lower part of the sheet feeder main body 13. When the paper feed table detection signal of the paper feed table bottom position detection sensor 24 is input to the control means 23, the downward movement of the paper feed table 3 is stopped and the paper feed table 3 is below the lowest position. Do not move to.

  In FIG. 1, a paper feed path 25 is installed in the upper part of the paper feed apparatus main body 13, and a paper feed means is provided upstream of the paper feed path 25 in the recording material feed direction (right side in FIG. 1). 4 is arranged. The sheet feeding means 4 includes a pickup roller 26 that feeds a recording material (the uppermost recording material of the sheet feeding table 3) S at the sheet feeding position h1 from the sheet feeding table 3 toward the sheet feeding path 25, and the pickup roller. 26, a paper feed roller 28 connected to the paper feed roller 28 via an arm 27, and a separation roller 30 in contact with the paper feed roller 28. The sheet feeding means 4 is configured such that the arm 27 can be rotated around the rotation center of the sheet feeding roller 28. The space above the sheet feed table 3 can be opened by rotating it in a clockwise direction (to make it stand upright). Thus, when the recording material S is replenished on the paper feed tray 3 in the paper feeder main body 13, the upper portion of the paper feed tray 3 (the uppermost recording material S when the recording material S is loaded). The space is opened toward the outside of the paper feeder main body 13, and the replenishment work of the recording material S becomes easy.

  Further, in the sheet feeding means 4 shown in FIG. 1, the arm 27 is urged clockwise around the rotation center of the sheet feeding roller 28 by a spring or a weight (not shown), and the pickup roller 26 is in the sheet feeding position h1. The recording material S can be contacted at a desired pressure. Further, a paper feed height position detection sensor 31 is attached to the paper feed means 4. The paper feed height position detection sensor 31 detects whether or not the recording material S is located at a desired paper feed position h1 through the posture (rotation angle) of the arm 27. ing. The detection signal of the paper feed height position detection sensor 31 is input to the control means 23.

  In the sheet feeding means 4 having such a configuration, when a print job is executed, the pickup roller 26 sends the recording material S on the sheet feeding table 3 to the nip portion between the sheet feeding roller 28 and the separation roller 30, and this sheet feeding roller 28 and the separation roller 30 feeds only one sheet of recording material S to the downstream side in the sheet feeding direction of the sheet feeding path 25 (left side of the sheet feeding roller 28 in FIG. 1). It is designed to return to 3 above. The recording material S sent out to the paper feed path 25 by the paper feed means 4 is fed into the image forming apparatus main body 5 by a feed roller pair 32 positioned on the downstream end side in the paper feed direction of the paper feed path 25. It has become.

  In FIG. 1, an upper cover 33 is detachably attached to the upper end portion of the sheet feeding device main body 13, and the sheet feeding table 3 (when the recording material S is stacked on the sheet feeding table 3). The upper space of the uppermost recording material S) can be easily opened to the outside. An opening / closing detection sensor 34 that detects opening / closing of the upper cover 33 is installed at the upper end of the sheet feeding device body 13. In general, when the upper cover 33 is opened, it is considered that it is time to replenish the recording material S onto the paper feed table 3 except during jam processing, so that it can function as a replenishment operation detecting means. .

  As shown in FIGS. 1 and 2, the sheet feeding device 2 has a replenishment height position h <b> 2 set at a height position lower than the sheet feeding position h <b> 1 by a predetermined dimension. When the recording material S is not loaded, the upper surface of the paper feed tray 3 is positioned at the replenishment height position h2, and when the recording material S is loaded on the paper feed tray 3, the uppermost position is set. First replenishment height detecting means 35 for detecting the upper surface of the sheet feed table 3 or the uppermost recording material S and the second replenishment so that the upper surface of the recording material S is positioned at the replenishment height position h2. An hour height detecting means 36 is installed in the sheet feeder main body 13.

  As shown in FIG. 1, the first replenishment height detection means 35 is a lever swingably attached to the abutting plate 37 side against which the leading end of the recording material S on the sheet feeding table 3 abuts. A member 38 and an optical sensor 40 that detects the posture (swing angle) of the lever member 38 are provided. The lever member 38 has a substantially inverted L shape, and can be swung by a support shaft 41 on a frame (not shown) extending from the sheet feeding device body 13 or a frame (not shown) extending from the abutting plate 37. And is always urged clockwise by a spring (not shown). Then, the upper end portion of the lever member 38 abuts on the upper end edge of the uppermost recording material S on the paper feed table 3 or hits the upper end edge of the paper feed table 3 on which the recording material S is not stacked. The protrusion 42 which contacts is formed (refer FIG. 2). In the present embodiment, the shape of the projection 42 is pushed by the bundle of recording materials S supplied when the bundle of recording materials S is supplied onto the paper feed table 3, as shown in FIG. In order to prevent the recording material supply operation from being disturbed, the top portion has a substantially isosceles triangle protruding in the right direction in the figure. However, the present invention is not limited to this, and the recording material S is placed on the paper feed table 3. Any shape that can detect the replenishment and can detect the uppermost recording material S on the sheet feed table 3 may be used. A trapezoidal shape, an arc shape, a composite shape thereof, or the like is conceivable.

  As shown in detail in FIG. 2, the first replenishment height detection means 35 is configured such that the protrusion 42 of the lever member 38 abuts against the upper end edge of the uppermost recording material S on the paper feed table 3 or the lever. When the protrusion 42 of the member 38 is in an upright position (solid line position) in contact with the upper edge of the paper feed table 3 on which the recording material S is not stacked, the uppermost recording material S or the recording material on the paper feed table 3 A signal that detects the upper surface of the paper feed tray 3 on which S is not loaded is output to the control means 23 (see FIG. 1). On the other hand, in FIG. 2, the first replenishment height detecting means 35 is rotated clockwise (+ θ ° times) to the two-dot chain line position through the standing position when the lever member 38 is biased by a spring (not shown). (When the lever member 38 is swung), a signal indicating that the uppermost recording material S on the paper feed tray 3 or the upper surface of the paper feed tray 3 on which the recording material S is not loaded is detected is directed to the control means 23. Is not output. Further, in FIG. 2, the first replenishment height detecting means 35 is configured such that the tip of the protrusion 42 of the lever member 38 is pushed by the side surface 43 of the bundle of recording materials S and the side surface 44 of the sheet feed table 3 to When 38 rotates counterclockwise from the standing position to the dotted line position (rotates by −δ °) (rotates until the tip of the protrusion 42 of the lever member 38 is substantially flush with the surface of the abutting plate 37). Then, the signal indicating that the uppermost recording material S on the paper feed tray 3 or the upper surface of the paper feed tray 3 on which the recording material S is not loaded is not output to the control means 23.

  Further, the first replenishment height detection means 35 is disposed so as to be positioned at the center (CL1) in the width direction of the recording material S, as shown in FIG. However, the first replenishment height detection means 35 may not be arranged so as to be located in the center in the width direction of the recording material S because it is necessary to secure an arrangement space for the separation roller 30 and the like. In such a case, as shown in FIG. 3B, the first replenishment height detection means 35 may be disposed within a predetermined distance (L1) from the center of the recording material S in the width direction. preferable. The predetermined distance (L1) is, for example, about 60 mm when the recording material S is A4 size copy paper (backing paper printed on one side with an electrostatic copying printer). Even if the one end side and the other end side in the width direction are curled, it is an experiment that the first replenishment height detecting means 35 can detect a portion of the recording material S that is less influenced by curling (almost flat portion). (See FIG. 3C). The predetermined distance (L1) is a portion where there is no curling of the recording material S or as much as possible of the curling of the recording material S in consideration of the arrangement space between the first replenishment height detecting means 35 and other components. It is set so that a small portion can be detected by the first replenishment height detection means 35.

  As shown in FIGS. 1 and 3, the second replenishment height detecting means 36 is an optical sensor in which a light emitting element 45 and a light receiving element 46 are arranged to face each other, and each of the light emitting element 45 and the light receiving element 46. Are divided into one side 47 side (lower side of FIG. 3A) and the other side 48 side (upper side of FIG. 3A) of the sheet feeding base 3 and the recording material S, The light emitting element 45 and the light receiving element 46 are fixed in the sheet feeding apparatus main body 13. The second replenishment height detecting means 36 is configured such that the optical axes of the light emitting element 45 and the light receiving element 46 are orthogonal to the paper feeding direction, and the uppermost recording material on the paper feeding table 3 is used. When S is at a predetermined height position, or when the upper surface of the paper feed tray 3 when the recording material S is not on the paper feed tray 3 is at the predetermined height position, the light emitted from the light emitting element 45 is received by the light receiving element. 46, a signal indicating that the uppermost recording material S on the paper feed tray 3 or the upper surface of the paper feed tray 3 on which the recording material S is not loaded is detected is output to the control means 23. Yes.

  Further, the second replenishment height detection means 36 is disposed so as to be positioned at the center (CL2) in the direction along the feeding direction of the recording material S, as shown in FIG. However, the second replenishment height detection means 36 may not be disposed so as to be positioned at the center in the direction along the sheet feeding direction of the recording material S because it is necessary to secure an arrangement space for other members. . In such a case, as shown in FIG. 3B, the second replenishment height detection means 36 is set within a predetermined distance (L2) from the center in the direction along the feeding direction of the recording material S. It is preferable to arrange in. The predetermined distance (L2) is, for example, about 60 mm when the recording material S is A4 size copy paper (backing paper printed on one side with an electrostatic copying printer). Even if the front end side and the rear end side are curled, it has been confirmed by experiments that the second replenishment height detecting means 36 can detect a portion (almost flat portion) of the recording material S that is less influenced by curling. (See FIG. 3C). Note that the predetermined distance (L2) is a portion where there is no curling of the recording material S or as much as possible of the curling of the recording material S in consideration of the arrangement space between the second replenishment height detecting means 36 and other components. It is set so that a small portion can be detected by the second replenishment height detection means 36.

  Note that the control unit 23 displays data relating to the replenishment of the recording material S in the paper feeding device 2 (data indicating that there is no recording material on the paper feeding table) and other data and messages on the display unit (for example, liquid crystal). Display on the display panel 50.

(Operation status of the paper feeder)
Next, the operation state at the time of replenishment of the sheet feeding device 2 will be described based on the flowchart of FIG.

[When the bundle of supplied recording materials S is not curled]
First, a case where the bundle of recording materials S to be supplied is not curled will be described.

  When an operator opens the upper cover 33 to replenish the recording material S to the paper feeding device 2, the opening / closing detection sensor 34 detects that the upper cover 33 has been opened, and the detection signal is used as an opening / closing detection sensor 34. To the control means 23. As a result, the control means 23 determines that the replenishment operation has been started, outputs an operation start signal to the motor 15 of the paper feed table drive means 14, lowers the paper feed table 3 (step S1), and the paper feed table 3 The uppermost recording material S is moved downward from the paper feeding position h1 (see FIG. 4B).

  As shown in FIG. 4B, when the uppermost recording material S (hereinafter abbreviated as the uppermost paper) on the paper feed tray 3 is lowered from the paper feed position h1 to the replenishment height position h2, the first replenishment is performed. A detection signal (ON signal) indicating that the lever member 38 of the hour height detection means 35 has risen from the dotted line position to the solid line position (see FIG. 2) and the upper surface of the uppermost paper has been detected is the first detection height detection. It is output from the means 35 to the control means 23. In addition, the light receiving element 46 receives the light emitted from the light emitting element 45 of the second replenishment height detection means 36, and a detection signal (ON signal) indicating that the upper surface of the uppermost paper has been detected is the second replenishment height. It is output from the height detection means 36 to the control means 23. When the control means 23 receives the detection signals from the first replenishment height detection means 35 and the second replenishment height detection means 36 (step S2), the control means 23 detects the motor 15 of the paper feed table drive means 14. Stop operation. As a result, the paper feed tray 3 stops at a position where the upper surface of the uppermost paper coincides with the height position h2 during replenishment (step S3).

  Next, as shown in FIG. 4A, when a large number (for example, 500 sheets) of recording materials S (bundles of recording materials S) are newly loaded (supplied) on the paper feed tray 3, 1 The lever member 38 of the replenishment height detection means 35 rotates counterclockwise from the solid line position and falls to the dotted line position (see FIG. 2), and the first replenishment height detection means 35 turns OFF to the control means 23. A signal (replenishment detection signal) is output. The light emitted from the light emitting element 45 of the second replenishment height detection means 36 is blocked by the bundle of recording materials S, and the second replenishment height detection means 36 sends an OFF signal (replenishment detection signal) to the control means 23. Is output. Thereby, the control means 23 determines that the recording material (paper) S has been replenished (step S4), operates the motor 15 of the paper feed table drive means 14, and lowers the paper feed table 3 (step). S1). When the control means 23 receives an OFF signal from at least one of the first replenishment height detection means 35 and the second replenishment height detection means 36, it is assumed that the recording material (paper) S has been replenished. The determination is made (see steps S4 and S5).

  As shown in FIG. 4B, when the uppermost sheet of the recording material S replenished on the paper feed tray 3 is lowered to the replenishment height position h2, the first and second replenishment height detecting means 35, 36 are provided. Outputs an ON signal to the control means 23 (step S), and the control means 23 detects the motor 15 of the paper feed table drive means 14 based on the ON signals from the first and second replenishment height detection means 35 and 36. The operation is stopped (the paper feed table 3 is stopped) (step S3).

  When the first and / or second replenishment height detection means 35, 36 does not detect replenishment of the recording material S (steps S4, S5), and the open / close detection sensor 34 detects that the upper cover 33 is closed, The detection signal (replenishment operation end signal) is output from the open / close detection sensor 34 to the control means 23 (step S6). Then, the control means 23 operates the motor 15 of the paper feed table driving means 14 and raises the paper feed table 3 (step S7). As a result, the lever member 38 of the first replenishment height detection means 35 is pushed by the front end surface of the bundle of recording materials S and falls to the solid line position shown in FIG. An OFF signal is output to the control means 23. Further, the light emitted from the light emitting element 45 of the second replenishment height detection means 36 is blocked by the bundle of recording materials S and is not received by the light receiving element 46, and the second replenishment height detection means 36 to the control means 23. An OFF signal is output.

  Thereafter, when the uppermost sheet on the sheet feeding table 3 rises to the sheet feeding position h1, the uppermost sheet on the sheet feeding table 3 and the pickup roller 26 come into contact with each other at a desired contact pressure, and the sheet feeding height position detection sensor 31 is activated. Detecting that the uppermost sheet on the sheet feed tray 3 is positioned at the height of a predetermined sheet feed position h1, a detection signal is output from the sheet feed height position detection sensor 31 to the control means 23, and the sheet feed position is detected. It is determined that the paper board 3 is at the optimum height position for feeding the uppermost paper (step S8), and the replenishment operation of the recording material S is ended.

[When the bundle of supplied recording materials S is not stacked at the correct supply position]
Next, as shown in FIG. 5A, the leading end of the bundle of recording materials S replenished on the paper feed table 3 is not abutted against the abutting plate 37 (the leading end of the bundle of recording materials S). A case will be described in which a gap d1 is generated between the abutting plate 37) and the leading end position of the replenished recording material S is not at the correct replenishment position.

  In the case shown in FIG. 5A, the first replenishment height detection means 35 is not pushed by the replenished bundle of recording materials S and does not output an OFF signal to the control means 23. On the other hand, since the light emitted from the light emitting element 45 is blocked by the bundle of recording materials S and cannot be received by the light receiving element 46 (see FIG. 3), the second replenishment height detection means 36 has a second replenishment height. An OFF signal is output from the detection means 36 to the control means 23 (step S5).

  Based on the OFF signal from the second replenishment height detection means 36, the control means 23 operates the motor 15 of the paper feed table drive means 14 to lower the paper feed table 3 (step S11).

  When the paper feed table 3 is moved downward, the uppermost paper is lowered to the height position h2 during replenishment, and the light receiving element 46 receives light from the light emitting element 45 of the second replenishment height detecting means 36, the second replenishment time is reached. An ON signal is output from the height detection unit 36 to the control unit 23, and the control unit 23 determines that the uppermost sheet is at the replenishment height position h2 (step S12).

  When receiving the ON signal from the second replenishment height detecting means 36, the control means 23 stops the operation of the motor 15 of the paper feed table driving means 14 and stops the paper feed table 3 (step S3).

  Thereafter, the replenishment operation is completed through steps S4 to S8, or the operations of steps S4 to S5, steps S11 to S12, and step S3 are repeated a plurality of times, and then the replenishment operation is terminated through steps S4 to S8.

[When the leading and trailing ends of the replenished recording material S are curled upward]
Next, as shown in FIG. 5B, a case where the leading end side and the trailing end side of the bundle of recording materials S supplied on the sheet feeding table 3 are curled upward will be described.

  In the case as shown in FIG. 5B, as in the case of FIG. 5A, the OFF signal is not output from the first replenishment height detection means 35 to the control means 23, and the second replenishment height. An OFF signal is output from the detection means 36 to the control means 23. As a result, the sheet feeding device 2 performs the replenishment operation of the recording material S as in FIG.

[When the leading edge and the trailing edge of the replenished recording material S are curled downward]
Next, as shown in FIG. 5C, a case where the front end side and the rear end side in the paper feeding direction of the bundle of recording materials S supplied on the paper feeding base 3 are curled downward will be described.

  In the case shown in FIG. 5C, the second replenishment height detection means 36 is pushed by the bundle of replenished recording materials S, and the tip of the protrusion 42 of the lever member 38 is the same as the abutting plate 37. It falls so as to be positioned on the surface and outputs an OFF signal to the control means 23. On the other hand, the second replenishment height detecting means 36 receives the light emitted from the light emitting element 45 by the light receiving element 46 without being blocked by the bundle of recording materials S (see FIG. 3). An OFF signal is not output from the height detection means 36 to the control means 23 (step S5).

  The control means 23 operates the motor 15 of the paper feed table driving means 14 based on the OFF signal from the first replenishment height detection means 35 to lower the paper feed table 3 (step S11).

  The paper feed table 3 is moved downward, the uppermost paper is lowered to the height position h2 at the time of replenishment, and the protrusion 42 of the lever member 38 of the first replenishment height detection means 35 projects above the uppermost paper (FIG. 2). The first replenishment height detection means 35 outputs an ON signal to the control means 23, and the control means 23 has the uppermost paper at the replenishment height position h2. Is determined (step S12).

  When receiving the ON signal from the first replenishment height detection means 35, the control means 23 stops the operation of the motor 15 of the paper feed table driving means 14 and stops the paper feed table 3 (step S3).

  Thereafter, the replenishment operation of the recording material S is finished through steps S4 to S8, or the operations of steps S4 to S5, steps S11 to S12, and step S3 are repeated a plurality of times, and then the recording material is passed through steps S4 to S8. The S replenishment operation is terminated.

[When both ends in the width direction of the supplied recording material S are curled upward]
Next, as shown in FIG. 6A, a case where both ends in the width direction of the bundle of recording materials S supplied on the sheet feeding table 3 are curled upward will be described.

  In the case shown in FIG. 6A, the protrusion 38 of the lever member 38 of the first replenishment height detecting means 35 is pushed by the leading end of the replenished bundle of recording materials S to control the OFF signal 23. And the light emitted from the light emitting element 45 of the second replenishment height detection means 36 is blocked by the bundle of replenished recording materials S and cannot be received by the light receiving element 46, and the second replenishment height detection means. It is conceivable that 36 outputs an OFF signal to the control means 23. In such a case, the replenishment operation of the recording material S is performed through the same steps as when the bundle of replenished recording materials S is not curled (see FIG. 4).

  In the case shown in FIG. 6A, the protrusion 42 of the lever member 38 of the first replenishment height detecting means 35 is not pushed by the leading end of the bundle of recording materials S that has been replenished (FIG. 5). (Refer to (a)), the first replenishment height detection means 35 cannot output the OFF signal to the control means 23, and the recording material replenished with the light emitted from the light emitting element 45 of the second replenishment height detection means 36. It is conceivable that the second replenishment height detection means 36 outputs an OFF signal to the control means 23 because it is blocked by the bundle of S and cannot be received by the light receiving element 46. In such a case, the recording material S is replenished through the same steps as when the replenished bundle of recording materials S is not stacked at the correct replenishment position (see FIG. 5A).

[When both ends of the supplied recording material are curled downward]
Next, as shown in FIG. 6B, a case where both ends in the width direction of the bundle of recording materials S supplied on the sheet feeding table 3 are curled downward will be described.

  In the case shown in FIG. 6B, the protrusion 38 of the lever member 38 of the first replenishment height detecting means 35 is not pushed by the leading end of the bundle of recording materials S that has been replenished (skipping). The first replenishment height detection means 35 cannot output the OFF signal to the control means 23, and the light emitted from the light emitting element 45 of the second replenishment height detection means 36 is blocked by the bundle of recording materials S replenished. Accordingly, the light receiving element 46 cannot receive light, and the second replenishment height detecting means 36 outputs an OFF signal to the control means 23. In such a case, the recording material S is replenished through the same steps as when the replenished bundle of recording materials S is not stacked at the correct replenishment position (see FIG. 5A).

(Effect of this embodiment)
As described above, according to the present embodiment, the bundle of recording materials S that has been replenished is not warped and has been replenished, of course, when it is placed at the correct position on the paper feed table 3. The leading end of the bundle of recording materials S is displaced without being abutted against the abutting plate (reference surface on the leading end side in the feeding direction) 37, or the replenished bundle of recording materials S is warped. Even in such a case, the uppermost recording material S in the bundle of supplied recording materials S can be accurately detected, and the replenishment operation of the recording materials S can be executed accurately and smoothly.

  Further, in the present embodiment, the replenishment operation of the recording material S can be performed at a substantially constant replenishment height position h2 as compared with the conventional example in which the paper feed table 3 is lowered to the lowest position when the recording material S is replenished. This makes it easy for the operator to perform replenishment work (improves workability) and shortens the replenishment time.

  In the present embodiment, the first replenishment height detection means 35 also functions as a leading edge position detection sensor for the recording material S in the paper feeding direction. Further, since the second replenishment height detection means 36 is an optical sensor, it can be arranged away from the paper feed tray 3 and the degree of freedom of component layout in the paper feeder main body 13 is increased.

(Other variations)
In the above-described embodiment, the paper feed roller 28, the arm 27, the pickup roller 26, and the paper feed height position detection sensor 31 of the paper feed unit 4 are attached to the upper cover 33. When the roller 26 and the arm 27 are separated from the recording material S and the paper feed roller 28 is separated from the separation roller 30, the paper feed table 3 in the paper feeder main body 13 (when the recording material S is placed). May be opened to the outside of the sheet feeder main body 13.

  In the above embodiment, the opening / closing detection sensor 34 of the upper cover 33 is exemplified as the replenishment operation detecting means. However, the present invention is not limited to this. Replenishment operation detection means may be used.

  In the above-described embodiment, the sheet feeding device 2 is illustrated as being assembled on the outer side surface side of the image forming apparatus main body 5, but may be configured to be accommodated in the image forming apparatus main body 5. As described above, the sheet feeding device 2 built in the image forming apparatus main body 5 may use the opening / closing detection sensor for the opening / closing cover of the image forming apparatus 1 or the operation sensor for the drawer lever as the replenishment operation detecting means.

  Further, in the above embodiment, after the first and / or second replenishment height detection means 35, 36 detects the uppermost recording material (uppermost paper) on the paper supply table 3, The paper feed table may be lowered until a predetermined time has elapsed.

  The sheet feeding device according to the present invention is a mode of stacking recording materials, not exemplified in the above-described embodiment, on the sheet feeding table. In step S5 in FIG. After either one of the replenishment height detection means detects the replenishment of the paper and the paper feed table is lowered (step S11), in step S12, the first replenishment height detection means and the second replenishment height detection means. Even if the other of them is in a stacking mode in which the uppermost sheet on the sheet feeding table is detected, the recording material replenishing operation can be executed accurately and smoothly as in the above embodiment.

1 is a schematic configuration diagram of a sheet feeding device according to an embodiment of the present invention and an image forming apparatus including the sheet feeding device. It is a figure which expands and shows the structure of the 1st replenishment height detection means. FIG. 6A is a first plan view showing the positional relationship between a recording material on a paper feed tray and first and second replenishment height detection means. FIG. 6B is a second plan view showing the positional relationship between the recording material on the paper feed tray and the first and second replenishment height detection means. (C) is the figure of the recording material seen from the A direction of (a). (D) is a view of the recording material viewed from the B direction of (a). It is a 1st operation state figure of a paper feed stand. It is a 2nd operation state figure of a paper feed stand. It is a 3rd operation state figure of a paper feed stand. FIG. 6 is a flowchart for explaining an operation state of the sheet feeding device according to the present embodiment. It is a schematic block diagram of a conventional paper feeding device and an image forming apparatus provided with the same. It is a figure which shows the operating state of the paper feed stand in the conventional paper feeder.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Image forming apparatus, 2 ... Paper feed apparatus, 3 ... Paper feed stand, 4 ... Paper feed means, 12 ... Image forming part, 14 ... Paper feed stand drive means, 23 ... Control means, 34... Open / close detection sensor (supply operation detection means), 35... First supply height detection means, 36... Second supply height detection means, S.

Claims (4)

A feed stand that can be raised and lowered;
A sheet feeding means for feeding sheet-like recording materials on the sheet feeding table one by one from the sheet feeding table;
A sheet feeding table driving means for moving the sheet feeding table up and down;
Replenishment operation detecting means for detecting that an operation for replenishing a large number of the recording materials on the sheet feeding base is started;
First height detection at the time of replenishment for detecting the height position of the recording material located at the top of the plurality of recording materials replenished on the sheet feeding base at the leading end side in the feeding direction of the recording material Means,
At the time of the second replenishment in which the height position of the recording material located at the highest position among the plurality of recording materials replenished on the paper feed table is detected on the side surface orthogonal to the feeding direction of the recording material. Height detection means;
Control means for controlling the operation of the paper feed table driving means based on detection signals from the replenishment operation detection means, the first replenishment height detection means and the second replenishment height detection means. Means
(1) When the first replenishment height detection means and the second replenishment height detection means detect replenishment of the recording material after the detection signal from the replenishment operation detection means is input, The paper feed table driving means is operated until the height detection means during replenishment and the second height detection means during replenishment detect the height position of the recording material located at the uppermost position on the paper feed table. Lower the paper tray or
(2) or when the first replenishment height detection means or the second replenishment height detection means detects replenishment of the recording material after the detection signal from the replenishment operation detection means is input, Of the first replenishment height detection means or the second replenishment height detection means, the one that has detected the replenishment of the recording material detects the height of the recording material that is positioned at the top on the paper feed table. Until the paper feed table driving means is operated to lower the paper feed table,
A paper feeder characterized by that. The first replenishment height detection means is arranged at the center on the front end side of the recording material in a direction perpendicular to the feeding direction of the recording material,
The second replenishment height detection means is arranged at the central portion on the side surface side of the recording material in a direction along the feeding direction of the recording material.
The paper feeding device according to claim 1. The first replenishment height detection means is disposed within a range of 60 mm from the front end side central portion of the recording material in a direction orthogonal to the recording material feeding direction,
The second replenishment height detection means is disposed within a range of 60 mm from the central portion on the side surface side of the recording material in a direction along the feeding direction of the recording material.
The paper feeding device according to claim 1.   An image forming apparatus comprising: the paper feeding device according to claim 1; and an image forming unit that prints an image on a recording material fed from the paper feeding device.

Images