JP6043776B2 - Paper feeding device and image forming apparatus - Google Patents

Description

  The present invention relates to a sheet feeding device and an image forming apparatus including the sheet feeding device.

  The image forming apparatus is provided with a paper feeding device that accommodates paper used for printing and feeds paper. There are many types of paper feeders that can set a single size of paper so that a large size such as A3 paper can be accommodated. However, if, for example, A4 or B5 paper is set in a paper feeder corresponding to A3 size, the unused space can be increased. Therefore, there is a case where the number of sheets stored is increased by allowing a sheet bundle to be set in parallel in one sheet feeding device.

  Patent Document 1 discloses a sheet feeding device capable of setting two rows of paper bundles. Specifically, Patent Document 1 discloses that a first sheet stacking table can be moved up and down, a sheet is fed from the first sheet stacking table, and a second sheet stacking table that can be moved up and down is a first sheet stacking table. The sheet bundle on the second sheet stacking table is collectively transferred to the first sheet stacking table, and when the sheet bundle is transferred, the first sheet stacking table and the second sheet stacking table are transferred. Each stop position at which the sheet stacking table stops at substantially the same height position is detected, and when there are no more sheets on the first sheet stacking table, the sheet bundle on the second sheet stacking table is placed on the first sheet stacking table. Describes a sheet feeding apparatus capable of performing a tandem feeding operation that automatically transfers the sheet and continues the sheet feeding operation. With this configuration, during the tandem feeding operation, the occurrence of sheet bundle collapse is detected to try to eliminate the service call (Patent Document 1: Claim 1, paragraphs [0009] and [0010]).

JP 2009-263014 A

  In the sheet feeding device described in Patent Document 1, a bundle of sheets on a stacking table on which spare sheets are set is transferred to a stacking table with no sheets. On the other hand, there is a paper feeding device in which a plurality of trays are provided in a single paper feeding device so that paper can be fed from each tray (hereinafter, such a paper feeding device is referred to as “each tray independent paper feeding type feeding device”). "Paper device"). In other words, each tray independent sheet feed type sheet feeder can divide one (one stage) sheet feeder into a plurality of rooms and feed sheets from each room.

  Each tray independent sheet feeding type sheet feeding device can set a bundle of relatively small sized sheets in, for example, two rows. In such a tray independent sheet feed type sheet feeder, a sheet feed roller and a tray lifting mechanism are provided for each tray. Then, according to the remaining number of sheets in each tray, each tray is raised so that each sheet feeding roller and the sheet on each tray are in contact with each other.

  Each tray independent sheet feeding type sheet feeding device has an advantage that the space in the sheet feeding device can be effectively utilized and the number of sheets accommodated can be increased. On the other hand, in each tray independent paper feed type paper feeder, the size of one paper tray is small, and large paper (for example, A3 size or B4 size) cannot be set. Conventionally, there is no tray independent paper feed device that can load large size paper, and even if a user wants to load large size paper, it can be structured. However, there is a problem that it may not be easy to use.

  Here, the sheet feeding device described in Patent Document 1 can set two rows of sheet bundles in one space. However, it is not assumed that a sheet bundle having a size larger than the tray in the sheet feeding apparatus is set, and there is no related description. Therefore, based on the description in Patent Document 1, the above problem cannot be solved.

  The present invention has been made to solve the above-described problem, and in each tray independent sheet feeding type sheet feeding device, a large size set across a plurality of trays without using an expensive motor or circuit. Raise both trays without breaking the paper.

In order to achieve the above object, a paper feeding device according to a first aspect includes a first tray on which paper is placed, a first paper feeding roller that feeds the paper placed on the first tray, and the first tray. A first paper feed unit including a first elevating mechanism that raises the first tray by obtaining power from a first raising motor so that the paper placed on one tray comes into contact with the first paper feed roller; A second tray on which the paper is placed, a second paper feed roller that feeds the paper placed on the second tray, and a paper placed on the second tray is in contact with the second paper feed roller A second elevating mechanism that raises the second tray by obtaining power from a second elevating motor, and a second paper feeding unit provided in a horizontal direction with the first paper feeding unit, A partition plate standing between one tray and the second tray, and the first tray An upper sensor unit including a transmissive optical sensor mounted on the upper surface side of the tray, and a lower sensor unit including a transmissive optical sensor mounted on the lower surface side of the tray; When attached to the second tray and the first tray and the second tray have the same height, the upper edge is located above the second tray, and the lower edge is more than the second tray. A light-shielding plate provided on the lower side so as to shield light sensors of both the upper sensor part and the lower sensor part, and outputs of the upper sensor part and the lower sensor part are input, A control unit that controls ON / OFF of the first raising motor and the second raising motor . The upper sensor unit and the lower sensor unit output a light shielding output value indicating a light shielding state when the light shielding plate is shielded from light, and transmit a light transmitting state when the light shielding plate is not shielded from light. Output the output value. The partition plate is removed, and a sheet having a size larger than the placement surface of the first tray and the placement surface of the second tray is set across both the first tray and the second tray. In the case of the tray parallel ascending mode in which the tray is raised , when both the upper sensor unit and the lower sensor unit are at the light-shielding output value, both the first raising motor and the second raising motor are controlled. To raise both the first tray and the second tray, and when the output of the upper sensor unit is the light shielding output value while the output of the lower sensor unit is the transmission output value, While the second raising motor is stopped, the first raising motor is rotated to raise only the first tray, and the output of the upper sensor unit is the transmitted output value, while the lower sensor When the output of the section of the light shielding output value, the first rise motor to rotate the second rise motor while stopping raising only the second tray.

  According to the present invention, in each tray independent sheet feeding type paper feeder, both trays are lifted without using expensive motors and circuits and without breaking a large size sheet set across a plurality of trays. Can be made.

1 is a diagram illustrating a structure of a multifunction machine. FIG. 2 is a diagram illustrating a hardware configuration of a multifunction machine. It is a figure which shows an example of a paper feeder. It is a figure which shows an example of the left tray raising / lowering mechanism. It is a figure which shows an example of a right tray raising / lowering mechanism. It is a figure for demonstrating tray parallel raise mode. It is a figure which shows an example of attachment of the sensor part and light-shielding plate to each tray. It is a figure which shows an example of each sensor part. It is a figure which shows an example of each sensor part. It is a flowchart which shows an example of the flow of a process in tray parallel raise mode. It is a figure which shows an example of progress of the raise of both trays in tray parallel raise mode. It is a figure which shows an example of progress of the raise of both trays in tray parallel raise mode. It is a figure which shows an example of progress of the raise of both trays in tray parallel raise mode. It is a figure which shows an example of progress of the raise of both trays in tray parallel raise mode. It is a figure which shows an example of progress of the raise of both trays in tray parallel raise mode.

  Hereinafter, embodiments of the present invention will be described with reference to FIGS. Here, in this description, the multifunction peripheral 100 (corresponding to an image forming apparatus) provided with the paper feeding device 1 according to the present invention will be described as an example. However, each element such as configuration and arrangement described in this embodiment does not limit the scope of the invention and is merely an illustrative example.

(Outline of MFP 100)
First, an outline of the multifunction peripheral 100 according to the embodiment will be described with reference to FIG. FIG. 1 is a diagram illustrating the structure of the multifunction device 100.

  As shown in FIG. 1, the multifunction peripheral 100 of this embodiment has an operation panel 2 attached to the front front. The operation panel 2 includes a display unit 21 that displays information related to the multifunction peripheral 100 and information related to jobs. In addition, the operation panel 2 includes a hard key 23 and a touch panel unit 22 as an input unit for receiving user settings.

  A document transport unit 3 a and an image reading unit 3 b are provided on the upper part of the multifunction peripheral 100. The document transport unit 3a transports the set document and passes it through the reading position. The image reading unit 3b reads a document to be conveyed or a document set on a contact glass to generate image data.

  The multi-function device 100 includes a printing unit 4 inside. The printing unit 4 includes a paper feeding device 1, a conveyance unit 4a, an image forming unit 4b, a fixing unit 4c, and the like. The paper feeding device 1 accommodates a plurality of sheets and feeds out the sheets during printing (details will be described later). The transport unit 4a transports the paper supplied from the paper feeding device 1 to the image forming unit 4b, and transports the paper that has passed through the fixing unit 4c for discharge outside the apparatus. The image forming unit 4b forms a toner image based on the image data to be printed, and transfers the toner image to a sheet. The fixing unit 4c heats and pressurizes the paper on which the toner image is transferred, and fixes the toner image on the paper.

(Hardware configuration of MFP 100)
Next, a hardware configuration of the multifunction peripheral 100 according to the embodiment will be described with reference to FIG. FIG. 2 is a diagram illustrating a hardware configuration of the multifunction peripheral 100.

  As shown in FIG. 2, the multifunction peripheral 100 according to the present embodiment includes a main control unit 5. The main control unit 5 controls each unit included in the multifunction machine 100. The main control unit 5 includes a CPU 51, an image processing unit 52 that performs image processing on image data used for printing and transmission, and other electronic circuits and elements. The CPU 51 performs control and calculation of each unit of the multifunction peripheral 100 based on a control program and control data stored in the storage unit 53. The storage unit 53 is a combination of a non-volatile storage device such as ROM, flash ROM, and HDD and a volatile storage device such as RAM.

  The main control unit 5 controls the printing unit 4 (the paper feeding device 1, the conveyance unit 4a, the image forming unit 4b, the fixing unit 4c, and the like) (controls printing) an engine control unit 6 (corresponding to a control unit). In addition, an operation instruction is given to the document conveying unit 3a and the image reading unit 3b. The engine control unit 6 receives an instruction from the main control unit 5, causes the paper feeding device 1 to feed paper, transports the paper to the transport unit 4 a, causes the image forming unit 4 b to form and transfer a toner image, The fixing unit 4c is fixed. For example, the main control unit 5 instructs the engine control unit 6 to perform printing based on the printing data received from the computer 200 or the image data obtained by reading the originals of the original conveying unit 3a and the image reading unit 3b. 4 to perform printing (copy function, printer function).

  The engine control unit 6 includes an engine CPU 61 and an engine memory 62 that stores data and programs for controlling the printing unit 4 including the paper feeder 1. The engine CPU 61 controls the operation of the printing unit 4 based on an instruction from the main control unit 5, data in the engine memory 62, and a program. The engine control unit 6 receives outputs from various sensors provided in the printing unit 4 and recognizes the state of the printing unit 4. The engine control unit 6 includes a motor control circuit 63 for controlling ON / OFF and rotation speeds of various motors (see FIG. 3).

  A communication unit 54 is connected to the main control unit 5. The main control unit 5 controls the operation of the communication unit 54 and communication processing. The communication unit 54 is an interface for communicating with a computer 200 such as a personal computer or a server or the facsimile apparatus 300. The main control unit 5 controls operations such as notification on the operation panel 2. The main control unit 5 recognizes the operation and setting contents performed on the operation panel 2 and recognizes the setting contents and a print execution instruction.

(Outline of paper feeder 1)
Next, an outline of the sheet feeding device 1 according to the embodiment will be described with reference to FIGS. 1 and 3. FIG. 3 is a diagram illustrating an example of the sheet feeding device 1.

  The sheet feeder 1 according to the embodiment includes a left tray 71 (corresponding to a first tray) on which paper is placed and a right tray 81 (corresponding to a second tray) on which paper is placed in a housing 10. Including. The housing 10 has an open top surface and has a box shape. As shown in FIG. 1, slide units 12 are provided on the outer side of the housing 10 at left and right locations. With the slide unit 12, the housing 10 (the paper feeding device 1) and the members attached to the paper feeding device 1 can be pulled out horizontally from the multifunction peripheral 100.

  The user pulls out the housing 10 and loads the sheets from the upper surface direction. A bundle of about 500 to 1000 sheets can be set in one tray. When the housing 10 is pushed back after the paper is replenished, the slide unit 12 stores the housing 10 in the main body of the multi-function device 100 and closes the paper feeding device 1. The paper feeding device 1 is provided with an open / close sensor S1 for detecting opening / closing of the housing 10 (whether or not it is pulled out). Based on the output of the open / close sensor S1, the engine control unit 6 recognizes whether the housing 10 is pulled out or is closed and stored in the main body.

  The left tray 71 and the right tray 81 have the same size, and can stand alone up to A4 size paper. The left tray 71 is lifted and lowered by a left tray lifting mechanism 72 (corresponding to a first lifting mechanism) (details will be described later). The right tray 81 is raised and lowered by a right tray lifting mechanism 82 (corresponding to a second lifting mechanism) (details will be described later). The left tray 71 and the right tray 81 are provided side by side in the horizontal direction of the multi-function device 100.

  A left paper feed roller 73 (corresponding to a first paper feed roller) is provided for the left tray 71. The engine control unit 6 rotates the left ascending motor 74 (corresponding to the first ascending motor) of the left tray lifting mechanism 72 to indicate that the left tray 71 has been raised to the upper limit position (paper feeding position). 1) and the left tray 71 is raised until it contacts the left paper feed roller 73. In this way, the engine control unit 6 controls ON / OFF of the left ascending motor 74. When feeding paper from the left tray 71, the engine control unit 6 rotates the left paper feed motor 76 (see FIG. 3). As a result, the left paper feed roller 73 rotates. A left paper feed path 77 is provided at the paper feed destination of the left paper feed roller 73. The left paper feed path 77 is driven by the left paper feed motor 76 or other motors to convey paper.

  The left paper feed path 77 joins the paper fed from the left tray 71 to the transport unit 4a. A left separation roller pair 78 is provided in the upstream portion of the left paper feed path 77. The left separation roller pair 78 is rotated by receiving the drive of the left separation motor 79. The left separation roller pair 78 rotates in a direction in which the upper roller conveys the paper in the forward direction and the lower roller conveys the paper in the reverse direction. The left separation roller pair 78 returns the lower sheet to the left tray 71 when double feeding occurs. Further, the left paper feed path 77 is provided with a left paper feed sensor 710 for detecting whether or not the paper has been properly fed out.

  A right paper feed roller 83 (corresponding to a second paper feed roller) is provided for the right tray 81. The engine control unit 6 rotates the right ascending motor 84 (corresponding to the second ascending motor) of the right tray lifting mechanism 82 to indicate that the right tray 81 has moved up to the upper limit position (paper feeding position). 2) and the right tray 81 is raised until it contacts the right paper feed roller 83. Thus, the engine control unit 6 controls ON / OFF of the right ascending motor 84. When feeding paper from the right tray 81, the engine control unit 6 rotates the right paper feed motor 86 (see FIG. 3). As a result, the right paper feed roller 83 rotates. A right paper feed path 87 is provided at the paper feed destination of the right paper feed roller 83. The right paper feed path 87 is driven by the right paper feed motor 86 or other motors to convey paper.

  The right paper feed path 87 joins the paper fed from the right tray 81 to the transport unit 4a. A right separation roller pair 88 is provided in the upstream portion of the right paper feed path 87. The right separation roller pair 88 is rotated by being driven by the right separation motor 89. The right separation roller pair 88 rotates in a direction in which the upper roller conveys the paper in the forward direction and the lower roller in the reverse direction. When double feeding occurs, the right separation roller pair 88 sends the lower sheet back to the right tray 81. The right paper feed path 87 is provided with a right paper feed sensor 810 for detecting whether or not the paper has been properly fed out.

  The left paper feed motor 76, the left separation motor 79, the left tray lifting mechanism 72, the left upper limit sensor 75, and the like constitute the first paper feed unit 7. The first sheet feeding unit 7 is a part that feeds a bundle of sheets stored on the left side of the sheet feeding device 1. Further, the second paper feed unit 8 is configured by the right paper feed motor 86, the right separation motor 89, the right tray lifting mechanism 82, the right upper limit sensor 85, and the like. The second paper feeding unit 8 is a part that feeds a bundle of paper stored on the right side of the paper feeding device 1. The first paper feed unit 7 and the second paper feed unit 8 are provided side by side in the horizontal direction in the left-right direction of the multifunction peripheral 100.

  As shown in FIG. 1, a partition plate 11 is provided between the first paper feed unit 7 and the second paper feed unit 8. The partition plate 11 is a plate that stands in the vertical direction between the first paper feeding unit 7 and the second paper feeding unit 8, and the first paper feeding unit 7 and the second paper feeding unit along the front-rear direction of the multifunction peripheral 100. Partition 8 The partition plate 11 prevents the sheet from flowing from one of the left tray 71 and the right tray 81 to the other.

  Although details will be described later, the partition plate 11 is removable. In order to detect whether the partition plate 11 is attached or removed, a partition presence / absence sensor S2 is provided below the center of the sheet feeding device 1 and below the installation location of the partition plate 11. The engine control unit 6 can recognize and detect whether the partition plate 11 is attached or removed based on the output of the partition presence / absence sensor S2. The engine control unit 6 and the main control unit 5 may recognize the presence or absence of the partition plate 11 when the operation panel 2 receives an input as to whether or not the partition plate 11 is attached.

(Elevating mechanism)
Next, the raising / lowering mechanism of the left tray 71 and the right tray 81 will be described with reference to FIGS. FIG. 4 is a diagram illustrating an example of the left tray lifting mechanism 72. FIG. 5 is a diagram illustrating an example of the right tray lifting mechanism 82.

  First, the left tray lifting mechanism 72 will be described. First, as shown in FIG. 4, the left tray 71 is provided with two protrusions 72a protruding in the horizontal direction on each of the front side and the back side in a lateral direction (left and right direction) (total of four locations). . And the opening 72b is provided in the position corresponding to each protrusion 72a in the front wall 10a and the rear wall 10b of the housing 10, respectively. The opening 72b extends vertically. Each protrusion 72a protrudes outside the housing 10 from the opening 72b.

  As shown in FIG. 4, a left tray lifting mechanism 72 for the left tray 71 is provided on the left side of the housing 10. The left tray lifting mechanism 72 includes a wire 72c, a reel 72d, a rotating shaft 72e, a pulley 72f, and a joint portion 72g. Two wires 72c are provided at two locations on the outside of the front surface of the housing 10 and the outside of the back surface, respectively. Two reels 72 d are provided, one on each of the front side and the back side of the housing 10. One end of each wire 72c is connected to the reel 72d and the other end is connected to the upper surface of any one of the protrusions 72a, and each wire 72c is hung on a pulley 72f provided on the outer upper portion of the housing 10.

  A rotation shaft 72 e extending in the front-rear direction is provided at the lower left portion of the housing 10. The rotating shaft 72e is connected to the left ascending motor 74 through a joint portion 72g. The engine control unit 6 drives the left ascending motor 74 to rotate the rotating shaft 72e and the reel 72d in the direction in which the left tray 71 rises. Specifically, when the wire 72c is wound around the reel 72d, the left tray 71 is raised, and when the wire 72c is fed out, the left tray 71 is lowered.

  When the housing 10 is pulled forward, the connection between the left ascending motor 74 and the rotating shaft 72e is released by the action of the joint portion 72g. When the housing 10 is pulled forward, the connection between the left ascending motor 74 and the rotating shaft 72e is released at the joint portion 72g, so that the left tray 71 automatically lowers due to the action of gravity. In other words, when the predetermined lowering condition that the housing 10 is pulled forward and the left tray 71 is pulled out is satisfied, the left tray lifting mechanism 72 lowers the left tray 71 by the action of gravity. Finally, the left tray 71 descends to the lower limit position (reference position). The lower limit positions of the left tray 71 and the right tray 81 are the same. Therefore, when the housing 10 is pulled out, the left tray 71 and the right tray 81 have the same height.

  When the housing 10 is closed, the left ascending motor 74 and the rotating shaft 72e are connected by the action of the joint portion 72g. When recognizing that the housing 10 is closed based on the output of the open / close sensor S1, the engine control unit 6 drives the left ascending motor 74 to raise the left tray 71 to a position where paper can be fed.

  Specifically, the left paper feed roller 73 can swing in the vertical direction. When the left paper feed roller 73 is lifted by a certain amount due to the rise of the left tray 71, the left upper limit sensor 75 (switch) provided for the left paper feed roller 73 is turned on (or turned off). Based on the output change of the left upper limit sensor 75, the engine control unit 6 detects that the left tray 71 has reached the paper feed position (upper limit position). Then, the engine control unit 6 stops the left ascending motor 74.

  Next, the right tray lifting mechanism 82 will be described. Basically, the right tray lifting mechanism 82 has the same configuration as the left tray lifting mechanism 72. First, as shown in FIG. 5, the right tray 81 is provided with two protrusions 82a protruding in the horizontal direction on each of the front side and the back side in a horizontal direction (left and right direction) (total of four points). ). The front wall 10a and the rear wall 10b of the housing 10 are each provided with an opening 82b at a position corresponding to each protrusion 82a. The opening 82b extends vertically. Each protrusion 82a protrudes outside the housing 10 from the opening 82b.

  As shown in FIG. 5, a right tray lifting mechanism 82 for the right tray 81 is provided on the right side of the housing 10. The right tray lifting mechanism 82 includes a wire 82c, a reel 82d, a rotating shaft 82e, a pulley 82f, a joint portion 82g, and the like. Two wires 82c are provided at two locations on the front outside and the back outside of the housing 10, respectively. Two reels 82 d are provided, one on each of the front side and the back side of the housing 10. One end of each wire 82c is connected to the reel 82d, and the other end is connected to the upper surface of one of the protrusions 82a, and each wire 82c is hung on a pulley 82f provided on the outer upper portion of the housing 10.

  A rotation shaft 82 e extending in the front-rear direction is provided at the lower right portion of the housing 10. The rotating shaft 82e is connected to the right ascending motor 84 through the joint portion 82g. The engine control unit 6 drives the right ascending motor 84 to rotate the rotating shaft 82e and the reel 82d in the direction in which the right tray 81 ascends. Specifically, when the wire 82c is wound around the reel 82d, the right tray 81 is raised, and when the wire 82c is fed out, the right tray 81 is lowered.

  When the housing 10 is pulled forward, the connection between the right ascending motor 84 and the rotating shaft 82e is released by the action of the joint portion 82g. When the housing 10 is pulled forward, the connection between the right ascending motor 84 and the rotary shaft 82e is released at the joint portion 82g, so that the right tray 81 automatically lowers due to the action of gravity. In other words, when a predetermined lowering condition that the housing 10 is pulled forward and the right tray 81 is pulled out is satisfied, the right tray lifting mechanism 82 lowers the right tray 81 by the action of gravity. Finally, the right tray 81 moves down to the lower limit position (reference position).

  When the housing 10 is closed, the right ascending motor 84 and the rotary shaft 82e are connected by the action of the joint portion 82g. The engine control unit 6 recognizes that the housing 10 has been closed based on the output of the open / close sensor S1, and drives the right ascending motor 84 to raise the right tray 81 to a position where paper can be fed.

  Specifically, the right paper feed roller 83 can swing in the vertical direction. When the right paper feed roller 83 is lifted by a certain amount due to the rising of the right tray 81, the right upper limit sensor 85 (switch) provided on the right paper feed roller 83 is turned ON (or OFF). Based on the output change of the right upper limit sensor 85, the engine control unit 6 detects that the right tray 81 has reached the paper feed position (upper limit position). Then, the engine control unit 6 stops the right ascending motor 84.

(Tray parallel ascending mode)
Next, an outline of the tray parallel ascending mode in the sheet feeding device 1 according to the embodiment will be described with reference to FIG. FIG. 6 is a diagram for explaining the tray parallel ascending mode.

  The paper feeding device 1 according to the embodiment has a plurality of trays in a housing (inside the housing 10). As shown in the upper diagram of FIG. 6, the left tray 71 and the right tray 81 can be independently raised to the paper feeding position. Specifically, the engine control unit 6 raises the left tray 71 to the paper feed position (upper limit position) according to the thickness of the sheet bundle of the left tray 71, and rightward according to the thickness of the sheet bundle of the right tray 81. The tray 81 is raised to the paper feed position (upper limit position). Thus, the number of sheets of paper that can be accommodated in the paper feeding device 1 can be increased as compared with the paper feeding device 1 that can effectively use the space in the paper feeding device 1 and can accommodate only one paper size in the paper feeding device 1. . Also, A4 paper can be placed on one tray and B5 paper can be placed and set on the other tray, and the types of paper sizes can be increased.

  However, when the cross-sectional area of the paper feeding device 1 itself is the same (for example, the same or almost the same area as the cross-sectional area of the multifunction machine 100), if a plurality of trays are provided in the paper feeding device 1, one tray The size of becomes smaller. When the number of trays in the paper feeder 1 is one, the settable paper size is often A3 size in accordance with the size of the multifunction device 100. However, for example, when two trays are provided in the paper feeding device 1, the paper size that can be placed is up to ½ of the A3 size (that is, the A4 size). Accordingly, when a plurality of trays are provided in the paper feeding device 1, paper cannot be fed in a large size (for example, A3 or B4 size).

  Therefore, in the sheet feeding device 1 according to the present embodiment, the partition plate 11 is removable as shown in the lower diagram of FIG. Then, as shown in the lower diagram of FIG. 6, with the partition plate 11 removed, a sheet having a size larger than the placement surface 71a of the left tray 71 and the placement surface 81a of the right tray 81 (for example, A3 Or B4) can be set across both the left tray 71 and the right tray 81, and both trays can be raised together without breaking the sheet bundle. The mode in which both trays are raised in parallel is hereinafter referred to as “tray parallel ascending mode”.

(Configuration to raise the tray in parallel)
Next, a configuration for raising both trays in parallel will be described with reference to FIGS. FIG. 7 is a diagram illustrating an example of attaching the upper sensor unit 9a, the lower sensor unit 9b, and the light shielding plate 90 to each tray. 8 and 9 are diagrams illustrating an example of each sensor unit.

  When paper is placed across both trays (left tray 71 and right tray 81) and both trays are raised, if there is a difference in the ascending speed between left tray 71 and right tray 81, left tray 71 and right tray 81 In some cases, the height difference d of the tray 81 is increased, and the bundle of loaded sheets is broken. In a state where a bundle of sheets is broken, it is not possible to appropriately feed paper. Even if the sheet bundle does not collapse in the middle, if the height difference d between the left tray 71 and the right tray 81 is large when reaching the sheet feeding position, the sheet is fed due to the inclination of the sheet with respect to the sheet feeding direction. It may not be done properly.

  Therefore, when sheets are set across the left tray 71 and the right tray 81 in the tray parallel ascending mode of the sheet feeding device 1 of this embodiment and the trays are raised, the sheets may be collapsed regardless of the number of sheets. The height difference d between the left tray 71 and the right tray 81 is raised so as not to become larger than a certain value so as not to cause a problem in paper feeding.

  Here, in the sheet feeding device 1 of the present embodiment, a DC motor (brush motor) is used for the left ascending motor 74 and the right ascending motor 84. The brush motor is advantageous in that it is inexpensive because it is easy to obtain torque for raising the tray even when the load is large because a large number of sheets are loaded.

  However, the brush motor also has such aspects that, when a constant voltage (current) is supplied, the rotational speed has individual differences, and the rotational speed changes depending on the size of the load. Therefore, when using a brush motor for the left ascending motor 74 and the right ascending motor 84, rotating the two motors at the same speed and raising the left tray 71 and the right tray 81 at the same speed are possible when using a stepping motor. Compared to difficult. When a stepping motor is used, it is relatively easy to synchronize the rotational speeds of a plurality of motors with the same pulse frequency. However, when a stepping motor is used, the stepping motor itself is more expensive than a brush motor, and further, a circuit and a substrate for driving the stepping motor are required. For this reason, if a stepping motor is used, the cost of the sheet feeding device 1 may increase significantly.

  Therefore, in the sheet feeding device 1 of the present embodiment, as shown in FIG. 7, the heights of the two trays are maintained substantially the same by using only the upper sensor unit 9a, the lower sensor unit 9b, and the light shielding plate 90. While raising. Specifically, the upper sensor unit 9 a and the lower sensor unit 9 b are attached to the left tray 71. The attachment position is a position that does not interfere with the partition plate 11, and is provided below the left tray 71 and at a corner on the right front side or right back side of the left tray 71. The same sensor (sensor having the same specifications) can be used for the upper sensor unit 9a and the lower sensor unit 9b. Each of the upper sensor unit 9a and the lower sensor unit 9b is a transmissive optical sensor as shown in FIG.

  As shown in FIG. 8, the upper sensor unit 9a receives a light emitting unit 91a (for example, an LED) that emits light toward the light receiving unit 92a and light from the light emitting unit 91a, and a current (voltage) corresponding to the amount of received light. Is included. Further, as shown in FIG. 9, a lighting circuit 93a is provided that causes the light emitting unit 91a to emit light based on a signal from the engine control unit 6 to turn on, and turns off the light emitting unit 91a based on a signal that instructs to turn off.

  Similarly to the upper sensor unit 9a, the lower sensor unit 9b receives light from the light emitting unit 91b (for example, LED) that emits light toward the light receiving unit 92b and the light emitting unit 91b, and according to the amount of light received. It includes a light receiving portion 92b that outputs a current (voltage). Also, as shown in FIG. 9, a lighting circuit 93b is provided that causes the light emitting unit 91b to emit light based on a signal from the engine control unit 6 that instructs lighting, and that causes the light emitting unit 91b to turn off based on a signal that instructs to turn off.

  A light shielding plate 90 is attached to the right tray 81. The light shielding plate 90 is provided at a position corresponding to the concave portions of the upper sensor portion 9a and the lower sensor portion 9b. The light shielding plate 90 blocks or transmits light between the light emitting unit 91a and the light receiving unit 92a and between the light emitting unit 91b and the light receiving unit 92b according to the height of the right tray 81. In other words, the light shielding plate 90 is When the right tray 81 is raised or lowered, the light shielding plate 90 passes between the light emitting part 91a and the light receiving part 92a of the upper sensor part 9a and between the light emitting part 91b and the light receiving part 92b of the lower sensor part 9b. It is attached to such a position.

  The output of the light receiving unit 92a is input to the signal processing circuit 94a of the upper sensor unit 9a and the lower sensor unit 9b. The signal processing circuit 94a may be provided on the engine control unit 6 side, or the output of the light receiving unit 92a may be processed using the engine CPU 61. Then, the signal processing circuit 94a outputs High or Low depending on whether or not the output value of the light receiving unit 92a is greater than or equal to a predetermined threshold value. The engine control unit 6 receives the output of the upper sensor unit 9a (signal processing circuit 94a).

  On the other hand, the output of the light receiving unit 92b is input to the signal processing circuit 94b of the lower sensor unit 9b. The signal processing circuit 94b may be provided on the engine control unit 6 side, or the output of the light receiving unit 92b may be processed using the engine CPU 61. Then, the signal processing circuit 94b outputs High or Low depending on whether or not the output value of the light receiving unit 92b is greater than or equal to a predetermined threshold value. The engine control unit 6 also receives the output of the lower sensor unit 9b (signal processing circuit 94b).

  Here, in this description, the upper sensor unit 9a (signal processing circuit 94a) and the lower sensor unit 9b (signal processing circuit 94b) are High (ON) in the sense that they are shielded from light by the light shielding plate 90 (light shielding output value). Is output, and Low (OFF) is output as the meaning (transmission output value) that is not light-shielded by the light-shielding plate 90 and is in a transmissive state. The logic may be reversed.

  The light shielding plate 90 is attached so that when the left tray 71 and the right tray 81 have the same height, the outputs of the upper sensor portion 9a and the lower sensor portion 9b both output a light shielding output value (High). . The vertical length 90L of the light shielding plate 90 is the light between the optical axis 95a (level) of the optical sensor of the upper sensor unit 9a and the optical axis 95b (level) of the optical sensor of the lower sensor unit 9b. It is longer than the inter-axis distance L0 (see FIG. 7). In FIG. 7 and subsequent drawings, the positions (levels) of the optical axis 91a of the upper sensor unit 9a and the optical axis 95b of the lower sensor unit 9b are indicated by broken lines.

  The outputs of the upper sensor unit 9a and the lower sensor unit 9b are switched between Low and High when the optical axis (level) of the optical sensor and the upper or lower edge of the light shielding plate 90 are at the same height. (Switching between the transmission output value and the light shielding output value is performed). Therefore, the threshold value of the signal processing circuit 94a is an output value of the light receiving unit 92a when the edge of the light shielding plate 90 overlaps the optical axis 95a, and the threshold value of the signal processing circuit 94b is the light value of the edge of the light shielding plate 90. This is the output value of the light receiving portion 92b when the position overlaps the shaft 95b.

  More specifically, when the first tray and the second tray (the left tray 71 and the right tray 81) have the same height, the upper edge of the light shielding plate 90 is positioned above the left tray 71 and the right tray 81. The lower edge is located below the left tray 71 and the right tray 81, and is provided so as to shield both the upper sensor unit 9a and the lower sensor unit 9b. The vertical length 90L of the light shielding plate 90 is the distance L0 between the optical axes between the level of the optical axis 95a of the optical sensor of the upper sensor unit 9a and the level of the optical axis 95a of the optical sensor of the lower sensor unit 9b. Longer than. Further, the length 90L of the light shielding plate 90 in the vertical direction is equal to or less than the length obtained by adding a value equal to or less than the limit value to the inter-optical axis distance L0.

  Here, the limit value is a value indicating the limit of the height difference between the first tray and the second tray (the left tray 71 and the right tray 81) in the tray parallel ascending mode. The limit value is determined on the basis of experiments and the like, taking into consideration that paper can be properly fed after rising and the sheet bundle does not collapse. For example, the limit value is about 1 to 4 mm. Further, when the first tray and the second tray have the same height, the light shielding plate 90 has a level of the optical axis 95a of the optical sensor of the upper sensor unit 9a and a level of the optical axis 95b of the optical sensor of the lower sensor unit 9b. It is attached so that the center (the center of the distance L0 between the optical axes) and the center in the vertical direction of the light shielding plate 90 overlap.

  In this case, the upper side from the level of the optical axis 95a of the photosensor of the upper sensor unit 9a to the upper edge of the light shielding plate 90 when the first tray and the second tray (the left tray 71 and the right tray 81) are the same height. The protrusion length L1 is equal to the lower protrusion length L2 from the level of the optical axis 95b of the optical sensor of the lower sensor portion 9b to the lower edge of the light shielding plate 90. Specifically, the upper protrusion length L1 and the lower protrusion length L2 are the output change area width (for example, about ± 0.3 mm) of the optical sensor of the upper sensor unit 9a and the optical sensor of the lower sensor unit 9b, and the mounting error. It is determined in consideration of sheet metal length crossing. Therefore, the upper protrusion length L1 and the lower protrusion length L2 are, for example, about 0.5 to 1 mm. The shorter the upper protrusion length L1 and the lower protrusion length L2 are (the closer the vertical length 90L of the light shielding plate 90 is to the distance L0 between the optical axes), the difference in height between the trays at the completion of the ascent and during the ascent. Although it can be reduced and the accuracy can be increased, if the error or intersection is large, both the output of the upper sensor unit 9a and the output of the lower sensor unit 9b may be transmission output values even if both trays are the same height. Therefore, a certain amount of upper protrusion length L1 and lower protrusion length L2 are provided.

  Thus, although some errors occur, in the tray parallel ascending mode, the height difference between the two trays is ½ of the length 90L in the vertical direction of the light shielding plate 90 minus the distance L0 between the optical axes. Both trays can be raised while staying below (less than half the limit value) (details will be described later).

(Tray lift process flow in tray parallel lift mode)
Next, an example of the processing flow for raising the tray in the tray parallel raising mode will be described with reference to FIGS. FIG. 10 is a flowchart illustrating an example of a process flow in the tray parallel ascending mode. FIGS. 11-15 is a figure which shows an example of progress of the raise of both trays in tray parallel raise mode.

  First, the start of the flowchart of FIG. 10 will be described. The engine control unit 6 sets a condition for starting the parallel raising of both trays in the tray parallel raising mode that the partition plate 11 of the paper feeding device 1 is removed. The engine control unit 6 recognizes that the partition plate 11 has been removed based on the output of the partition presence / absence sensor S2. An input to the effect that the partition plate 11 has been removed may be made by operating the operation panel 2 without providing the partition presence / absence sensor S2. Therefore, the engine control unit 6 may recognize that the partition plate 11 has been removed based on the input to the operation panel 2.

  Further, the engine control unit 6 starts raising both trays to the paper feeding position in the tray parallel raising mode when the housing 10 of the paper feeding device 1 is pulled out and then pushed back (opened / closed). The conditions are as follows. By opening and closing the housing 10, both trays (the left tray 71 and the right tray 81) are lowered to the reference position (lower limit position).

  Specifically, this is the state shown in FIG. In order to raise, it is necessary for both trays to be lowered before ascending. Further, when the housing 10 is opened and closed, the partition plate 11 is removed, the accommodated sheets are replaced or replenished, and a bundle of sheets is set across both trays. Furthermore, as shown in FIG. 11, since the reference positions (positions where the trays are completely lowered) of both trays are the same, both trays have the same height.

  The start of FIG. 10 is a state in which the condition for starting the parallel raising of both trays (the left tray 71 and the right tray 81) in the tray parallel raising mode is satisfied.

  First, the engine control unit 6 determines whether the output values of both the upper sensor unit 9a and the lower sensor unit 9b are light-shielding output values (whether the left tray 71 and the right tray 81 are at the same height). Or whether both trays are at the reference position) (step # 1). If one of the output values of the upper sensor unit 9a and the lower sensor unit 9b is a transmission output value (No in step # 1), both trays are not lowered to the lower limit (reference position). There is a possibility that the heights of both trays are greatly deviated. When the tray is raised in such a state, the deviation increases, and the stored (set) sheet bundle may collapse. In addition, there may be a problem in the light shielding plate 90 such as misalignment or separation, or there may be a problem in the upper sensor unit 9a and the lower sensor unit 9b such as misalignment or failure of each sensor unit. is there.

  Therefore, when the transmission output value is the transmission output value, the engine control unit 6 proceeds to open and close the housing 10 again, and the heights of both trays are shifted at the present time, so that the light shielding plate 90 and each sensor should be inspected. Is displayed on the display unit 21 of the operation panel 2 (step # 2). Then, when an operation on a confirmation key (not shown) displayed on the screen is accepted by the touch panel unit 22, the flow returns to step # 1.

  On the other hand, when the engine control unit 6 has confirmed that the output values of both the upper sensor unit 9a and the lower sensor unit 9b are light-shielding output values and the heights of the left tray 71 and the right tray 81 are close to each other. (Yes in step # 1, the state shown in FIG. 11), the engine control unit 6 starts parallel raising processing of both trays (the left tray 71 and the right tray 81) (step # 13).

Then, the engine control unit 6 raises both trays by the following method (step # 4).
(1) When the output of the upper sensor unit 9a is a light shielding output value and the output of the lower sensor unit 9b is also a light shielding output value, the engine control unit 6 rotates both the left ascending motor 74 and the right ascending motor 84. Let
As shown in FIG. 12, when the outputs of the upper sensor unit 9a and the lower sensor unit 9b are both light-shielding output values, the heights of both trays are close to each other. When brush motors are used for the left ascending motor 74 and the right ascending motor 84, the ascending speeds of the left tray 71 and the right tray 81 are usually different due to individual differences in rotational speed. However, in the state shown in FIG. 12, there is no great difference in the height of the left tray 71 and the right tray 81, and even if the height difference is somewhat large, the paper bundle collapses or cannot be properly fed after completion of the rise. Does not occur. Therefore, as shown in FIG. 12, the engine control unit 6 rotates both the left raising motor 74 and the right raising motor 84 to raise both the left tray 71 and the right tray 81.

(2) When the output of the upper sensor unit 9a is a light-shielding output value while the output of the lower sensor unit 9b is a transmitted output value, the engine control unit 6 stops the right ascending motor 84 and stops the left ascending motor 74. Only rotate. As shown in FIG. 13, after aligning the heights of the left tray 71 and the right tray 81, the output value of the upper sensor unit 9a is a light shielding output value, and the output of the lower sensor unit 9b is a transmission output value. The engine control unit 6 recognizes that the right tray 81 is at a higher position and the left tray 71 is at a lower position. If the rising of the right tray 81 is continued in the state shown in FIG. 13, the difference in height between the left tray 71 and the right tray 81 becomes large, which may cause a problem that the sheet bundle collapses or cannot be fed properly after completion of the lifting. Therefore, in the state shown in FIG. 13, the engine control unit 6 rotates the left ascending motor 74 while stopping the right ascending motor 84 and raises only the left tray 71 so as to catch up with the right tray 81.

(3) When the output of the upper sensor unit 9a is a transmission output value, while the output of the lower sensor unit 9b is a light-shielding output value, the engine control unit 6 stops the left ascending motor 74 and stops the right ascending motor 84. Only rotate. As shown in FIG. 14, after the heights of the left tray 71 and the right tray 81 are aligned, the output value of the upper sensor unit 9a is a transmission output value, and the output of the lower sensor unit 9b is a light shielding output value. The engine control unit 6 recognizes that the left tray 71 is at a higher position and the right tray 81 is at a lower position. If the left tray 71 continues to rise in the state shown in FIG. 14, the difference in height between the left tray 71 and the right tray 81 becomes large, which may cause a problem that the sheet bundle collapses or cannot be fed properly after completion of the rise. Therefore, in the state shown in FIG. 14, the engine control unit 6 rotates the right ascending motor 84 while stopping the left ascending motor 74 and raises only the right tray 81 so as to catch up with the left tray 71.

  And the engine control part 6 confirms the output of the right upper limit sensor 85 periodically. Specifically, the engine control unit 6 periodically touches the loaded paper bundle with the right paper feed roller 83 and lifts the right paper feed roller 83 swinging up and down to the right tray 81 and the paper. Based on this, it is checked whether or not the output value of the right upper limit sensor 85 has changed to the left tray 71 and right tray 81 sheet feed position (upper limit position) (step # 5).

  If the right tray 81 (right paper feed roller 83) has not reached the height of the paper feed position (No in step # 5), the flow returns to step # 4. As a result, until reaching the paper feed position, the engine control unit 6 keeps both trays (the first tray and the second tray) at substantially the same height while preventing the height difference d between the trays from increasing. While raising.

  On the other hand, when the right tray 81 (right paper feed roller 83) reaches the height of the paper feed position (Yes in step # 5, the state shown in FIG. 15), the engine control unit 6 raises the left ascending motor 74 and the right ascending. The motor 84 is stopped (step # 6). Then, this flow ends (END).

  Here, the sheet feeding device 1 is provided with sheet feeding rollers (left sheet feeding roller 73 and right sheet feeding roller 83) for each tray so that sheet feeding can be performed from both trays. Further, a left upper limit sensor 75 that detects that the left tray 71 has reached the sheet feeding position by contacting the uppermost sheet among the sheets placed on the left tray 71 with the left sheet feeding roller 73, and a right tray 81. A right upper limit sensor 85 is provided for detecting that the right tray 81 has reached the paper feeding position when the right paper feeding roller 83 comes into contact with the uppermost paper among the placed papers.

  The right paper feed roller 83 is installed at a position where the paper transport distance to the printing position (image forming unit 4b) is shorter than the left paper feed roller 73. The right paper feed roller 83 and the right upper limit sensor 85, which have a short transport distance to the image forming unit 4b in relation to the paper feed path, are provided below the left paper feed roller 73 and the left upper limit sensor 75. For this reason, the right paper feed roller 83 gets in the way when the left paper feed roller 73 is raised until it touches the uppermost position of the sheet bundle. Even if both trays are raised until the sheet comes into contact with the left sheet feed roller 73, even if the left sheet feed roller 73 is rotated in consideration of the position of the entrance of the sheet feed path of the left sheet feed roller 73, A large-size sheet set across the left tray 71 and the right tray 81 cannot be transported toward the transport unit 4a.

  Therefore, in the tray parallel ascending mode, the engine control unit 6 raises the left tray 71 and the right tray 81 to the paper feeding position of the right tray 81 based on the right upper limit sensor 85 and rotates the right paper feeding roller 83 to the left. The sheet placed across the tray 71 and the right tray 81 is fed. In other words, a large-size sheet is set so as to be fed from the right sheet feed roller 83. Then, after completion of raising of both trays in the tray parallel raising mode, the left paper feeding roller is not rotated.

  In the paper feeder 1 in which a plurality of trays are provided in a single housing, an inexpensive DC motor (brush motor) is used because it is easy to obtain a large torque for raising a tray on which a large amount of paper is set. Is used. However, in the case of an inexpensive brush motor, the rotational speed changes depending on the size of the load, and when the same voltage and current are supplied, the rotational speed of each motor varies even with the same load (individual difference d). While maintaining the height of all trays at the same height, it is difficult to match the ascending speed of all trays by rotating each motor at a constant speed.

  Therefore, the paper feeding device 1 according to the embodiment includes a first tray (left tray 71) on which paper is placed, and a first paper feeding roller (left paper feeding roller 73) that feeds the paper placed on the first tray. ) And a first elevating mechanism (left) that obtains power from the first elevating motor (left elevating motor 74) and raises the first tray so that the paper placed on the first tray is in contact with the first paper feed roller. Tray raising and lowering mechanism 72), a first paper feed unit 7 including a paper, a second tray (right tray 81) on which paper is placed, and a second paper feed roller (feeding out paper placed on the second tray) The second paper feed roller 83) and a second tray that lifts the second tray by obtaining power from the second lift motor (right lift motor 84) so that the paper placed on the second tray contacts the second paper feed roller. 2 lifting mechanism (right tray lifting mechanism 82), and the first A second paper feeding unit 8 provided in parallel with the paper unit 7, a partition plate 11 standing between the first tray and the second tray, and a transmission provided on the upper surface side of the tray. An upper sensor unit 9a including a mold type optical sensor, a lower sensor unit 9b including a transmission type optical sensor provided on the lower surface side of the tray and attached to the first tray, and a second tray attached to the first tray. And the second tray have the same height, the upper edge is located above the second tray, and the lower edge is located below the second tray so that the upper sensor portion 9a and the lower sensor portion are The light shielding plate 90 provided to shield both the light sensors 9b, and the outputs of the upper sensor portion 9a and the lower sensor portion 9b are inputted, and ON / OFF of the first raising motor and the second raising motor is controlled. System (Engine control unit 6) and the partition plate 11 are removed, and a sheet having a size larger than the placement surface (71a, 81a) of each of the first tray and the second tray is placed on both the first tray and the second tray. And a tray parallel ascending mode in which both trays are set up and raised. The upper sensor unit 9a and the lower sensor unit 9b output a light shielding output value indicating a light shielding state when the light shielding plate 90 is shielded from light, and transmit a light transmitting state when the light shielding plate 90 is not shielded from light. The transmission output value shown is output. In the tray parallel ascending mode, the control unit (engine control unit 6) rotates both the first ascending motor and the second ascending motor when both the upper sensor unit 9a and the lower sensor unit 9b are light-shielding output values. Both the first tray and the second tray are raised, and when the output of the upper sensor unit 9a is the light shielding output value while the output of the lower sensor unit 9b is the transmission output value, the second raising motor is stopped. Rotate the first raising motor to raise only the first tray, and stop the first raising motor when the output of the upper sensor unit 9a is the transmission output value while the output of the lower sensor unit 9b is the light shielding output value The second raising motor is rotated while raising only the second tray.

  When the outputs of the upper sensor unit 9a and the lower sensor unit 9b are both light-shielding output values and both trays (the first tray and the second tray) are at the same height (when the heights are close), the first Both the ascending motor (left ascending motor 74) and the second ascending motor (right ascending motor 84) rotate. Therefore, both trays can be quickly raised. Further, when the output value of the upper sensor unit 9a is a transmissive output value, the upper edge of the light shielding plate 90 is below the upper sensor unit 9a, and the light shielding plate 90 is more than the first tray (left tray 71). It can be recognized that the rising of the attached second tray (right tray 81) is delayed. In this case, since only the second tray is raised, the difference in height between the first tray and the second tray is not enlarged. Further, when the output value of the lower sensor unit 9b is a transmission output value, the lower edge of the light shielding plate 90 is above the lower sensor unit 9b, and the second tray to which the light shielding plate 90 is attached. It can be recognized that the rise of the first tray is delayed. Also in this case, since only the first tray is raised, the difference in height between the first tray and the second tray is not enlarged.

  Accordingly, the difference in height between the two trays (the left tray 71 and the right tray 81) does not increase, and there is no problem with the difference in height between the two trays (there is no breakage of the sheet bundle or feeding error after the rise). Both trays can be quickly raised in parallel while being stored inside. Therefore, each tray independent paper feed device 1 can set paper of a large size (paper larger than both trays) that could not be set conventionally and can feed paper. Further, it is possible to provide each tray independent paper feed device 1 that is easy to use and can be used without problems even when a large size paper is set.

  In addition, even if an inexpensive motor such as a brush motor is used without using a stepping motor or a driving circuit for the stepping motor, both trays can be raised quickly without causing collapse of the sheet bundle placed over the two. Can do. Therefore, it is possible to provide an easy-to-use paper feeding device 1 while reducing the manufacturing cost of the paper feeding device 1.

  Further, a limit value of a difference in height between the first tray (left tray 71) and the second tray (right tray 81) in the tray parallel ascending mode is determined in advance, and the light shielding plate 90 has a vertical length 90L. Is longer than the inter-optical axis distance L0 between the level of the optical axis 95a of the optical sensor of the upper sensor unit 9a and the level of the optical axis 95b of the optical sensor of the lower sensor unit 9b. It is below the length which added the following values.

  Thereby, the vertical length 90L of the light shielding plate 90 is set to such a length that the difference between the heights of both trays is equal to or less than the limit value when both trays are raised (in the tray parallel raising mode). Therefore, both trays will rise within a range where the height difference between both trays does not exceed the limit value, and it is difficult for paper bundles to collapse at the time of ascent and paper feed errors after completion of the ascent. it can.

  Further, when the first tray (left tray 71) and the second tray (right tray 81) have the same height, the light shielding plate 90 has the level of the optical axis 95a of the optical sensor of the upper sensor unit 9a and the lower sensor unit 9b. The light sensor is attached so that the center of the level of the optical axis 95b of the light sensor overlaps the center of the light shielding plate 90 in the vertical direction.

  Accordingly, when the first tray (left tray 71) and the second tray (right tray 81) are at the same height, the light shielding plate 90 and the light shielding plate 90 are arranged at the center position in the vertical direction of the first tray and the second tray. It is attached so that the center position of the up and down direction overlaps. Thereby, when the ascent is completed, the difference in average height between the first tray and the second tray can be brought close to 0 (zero). Accordingly, the heights of both trays are more easily matched.

  The second paper feed roller (right paper feed roller 83) is installed at a position where the paper transport distance to the position where printing is performed is shorter than the first paper feed roller (left paper feed roller 73). The sheet feeding device 1 detects that the first tray has reached the sheet feeding position by contacting the top of the sheets placed on the first tray (left tray 71) with the first sheet feeding roller. 1 upper limit sensor (left upper limit sensor 75) and the uppermost sheet among the sheets placed on the second tray (right tray 81), and the second feed roller comes into contact with the second tray, the feed position And a second upper limit sensor (right upper limit sensor 85) provided below the first upper limit sensor. In the tray parallel ascending mode, the control unit (engine control unit 6) raises the first tray and the second tray to the feeding position of the second tray and rotates the second feeding roller based on the second upper limit switch. Thus, the sheet placed across the first tray and the second tray is fed.

  As a result, the first tray and the second tray are raised with the position where the sheet feeding roller located below can be fed as the upper limit position, and the time required for raising both trays can be shortened. In addition, the paper placed across the first tray and the second tray can be quickly sent to the printing position.

  When a predetermined lowering condition is satisfied, the first elevating mechanism (left tray elevating mechanism 72) uses the first tray as a reference when the first tray (left tray 71) is pulled out. The second elevating mechanism (right tray elevating mechanism 82) lowers the second tray to the same position as the first tray by the action of gravity when the second tray (right tray 81) is pulled out.

  For example, when both of the trays of the sheet feeding device 1 are pulled out (when the housing 10 is pulled out), when the predetermined lowering conditions are satisfied, the heights of both trays are the same. As a result, when the paper is set across the trays, the paper bundle does not tilt or collapse from the time of placement. Moreover, it can be raised, maintaining both trays at substantially the same height from the beginning of raising the first tray and the second tray.

  Further, the image forming apparatus (multifunction peripheral 100) includes the paper feeding device 1 according to the embodiment. Since each tray independent sheet feeding type sheet feeding device 1 that can set a large size that could not be set conventionally and can be used without any problem even when a large size sheet is set, the image forming apparatus is easy to use. Can be provided. Further, even if the convenience is improved as compared with the conventional case, an increase in the manufacturing cost of the sheet feeding device 1 can be suppressed, so that an image forming apparatus with high cost competitiveness can be provided.

(Modification 1)
In the above-described embodiment, an example in which the upper sensor unit 9a and the lower sensor unit 9b are provided on the left tray 71 and the light shielding plate 90 is provided on the right tray 81 has been described. However, the light shielding plate 90 may be provided in the left tray 71, and the upper sensor unit 9a and the lower sensor unit 9b may be provided in the right tray 81. In this case, the left tray 71 to which the light shielding plate 90 is attached becomes the second tray, and the left raising motor 74 that raises the left tray 71 becomes the second raising motor. Further, the right tray 81 to which the upper sensor portion 9a and the lower sensor portion 9b are attached becomes the first tray, and the right ascending motor 84 that raises the right tray 81 becomes the first ascending motor. When both the upper sensor unit 9a and the lower sensor unit 9b have light shielding output values, the engine control unit 6 rotates both the right ascending motor 84 and the left ascending motor 74 so that both the first tray and the second tray are rotated. Raise. Further, when the output of the upper sensor unit 9a is a light shielding output value while the output of the lower sensor unit 9b is a transmission output value, the engine control unit 6 stops the left ascending motor 74 (second ascending motor). Then, the right raising motor 84 (first raising motor) is rotated to raise only the first tray (right tray 81). Further, when the output of the upper sensor unit 9a is a transmission output value and the output of the lower sensor unit 9b is a light shielding output value, the engine control unit 6 stops the right ascending motor 84 (first ascending motor). The right raising motor 84 (second raising motor) is rotated to raise only the second tray (left tray 71).

  Therefore, in the embodiment, the correspondence relationship is “left” = “first”, “right” = “second”, but in this modification, “right” = “first”, “left” = “first” All of the above explanations can be applied, although the corresponding relationship is “2”.

(Modification 2)
In the embodiment described above, the type of paper feeding device 1 that feeds paper from the tray in the right direction has been described. However, the present invention can also be applied to a paper feeding device 1 that feeds paper rightward from the tray. In this case, the left tray 71 in the above description corresponds to the right tray 81 (first tray) in the description of the above embodiment in the paper feeding device 1 of the type that feeds paper in the left direction. Further, the right tray 81 in the sheet feeding device 1 of the type that feeds the sheet in the left direction corresponds to the left tray (second tray) in the description of the above embodiment.

  Embodiment disclosed this time is an illustration in all the points, Comprising: It is not restrictive. The scope of the present invention is shown not by the description of the above-described embodiment but by the scope of claims for patent, and further includes meanings equivalent to the scope of claims for patent and all modifications within the scope.

DESCRIPTION OF SYMBOLS 1 Paper feeder 11 Partition plate 6 Engine control part (control part) 7 1st paper feed part 71 Left tray (1st tray)
72 Left tray lifting mechanism (first lifting mechanism)
73 Left feed roller (first feed roller)
74 Left lift motor (first lift motor)
75 Upper left sensor (first upper sensor)
8 Second paper feed unit 81 Right tray (second tray)
82 Right tray lifting mechanism (second lifting mechanism)
83 Right paper feed roller (second paper feed roller)
84 Right ascending motor (second ascending motor)
85 Upper right sensor (second upper sensor)
9a Upper sensor part 90 Light shielding plate 91a Light emitting part 91b Light emitting part 95a Optical axis 9b Lower sensor part 92a Light receiving part 92b Light receiving part 95b Optical axis 100 Multifunction machine (image forming apparatus)
L0 Distance between optical axes

Claims (6)

A first tray on which paper is placed, a first paper feed roller for feeding out the paper placed on the first tray, and a paper placed on the first tray so as to be in contact with the first paper feed roller A first feed mechanism including a first lifting mechanism that lifts the first tray by obtaining power from a first lifting motor;
A second tray on which the paper is placed, a second paper feed roller that feeds the paper placed on the second tray, and a paper placed on the second tray so as to contact the second paper feed roller A second elevating mechanism that raises the second tray by obtaining power from the second raising motor, and a second paper feeding unit provided side by side with the first paper feeding unit,
A partition plate standing between the first tray and the second tray;
An upper sensor unit including a transmissive optical sensor attached to the first tray and provided on the upper surface side of the tray;
A lower sensor unit that is attached to the first tray and includes a transmissive optical sensor provided on the lower surface side of the tray;
When attached to the second tray and the first tray and the second tray are at the same height, the upper edge is located above the first tray and the second tray, and the lower edge is the A light shielding plate that is located below the first tray and the second tray and is provided so as to shield the light sensors of both the upper sensor portion and the lower sensor portion;
The outputs of the upper sensor unit and the lower sensor unit are input, and includes a control unit that controls ON / OFF of the first raising motor and the second raising motor ,
The upper sensor unit and the lower sensor unit output a light shielding output value indicating a light shielding state when the light shielding plate is shielded from light, and transmit a light transmitting state when the light shielding plate is not shielded from light. Output the output value
The partition plate is removed, and a sheet having a size larger than the placement surface of the first tray and the second tray is set across both the first tray and the second tray, and both trays are raised. In the case of the tray parallel ascending mode ,
The controller is
When both the upper sensor unit and the lower sensor unit are at the light shielding output value, both the first tray and the second tray are raised by rotating both the first raising motor and the second raising motor. Let
When the output of the upper sensor unit is the light-shielding output value and the output of the lower sensor unit is the transmission output value, the first raising motor is rotated while the second raising motor is stopped, and the first raising motor is rotated. Raise only one tray,
When the output of the upper sensor unit is the transmitted output value and the output of the lower sensor unit is the light-shielding output value, the second raising motor is rotated while the first raising motor is stopped, and the second raising motor is rotated. A sheet feeding device that raises only two trays.
A limit value of a difference in height between the first tray and the second tray in the tray parallel ascending mode is determined in advance;
The vertical length of the light shielding plate is longer than the distance between the optical axes between the optical axis level of the optical sensor of the upper sensor unit and the optical axis level of the optical sensor of the lower sensor unit, The sheet feeding device according to claim 1, wherein the sheet feeding device has a length equal to or less than a length obtained by adding a value equal to or less than the limit value to an inter-axis distance.   When the first tray and the second tray are at the same height, the light-shielding plate has an optical axis level of the optical sensor of the upper sensor unit and a center of the optical axis level of the optical sensor of the lower sensor unit. The sheet feeding device according to claim 2, wherein the light shielding plate is attached so that a center in a vertical direction overlaps. The second paper feed roller is installed at a position where a paper transport distance to a position where printing is performed is shorter than the first paper feed roller,
A first upper limit sensor for detecting that the first tray has reached the paper feed position by contacting the top of the papers placed on the first tray with the first paper feed roller;
The first upper limit sensor detects that the second tray has reached the paper feed position by contacting the uppermost paper among the papers placed on the second tray with the second paper feed roller. A second upper limit sensor provided on the lower side,
The controller raises the first tray and the second tray to the paper feeding position of the second tray and rotates the second paper feeding roller based on the second upper limit sensor in the tray parallel raising mode. 4. The sheet feeding device according to claim 1, wherein the sheet feeding unit is configured to feed a sheet placed across the first tray and the second tray. 5. Before Symbol first elevating mechanism, when the first tray is pulled out, by the action of gravity lowers the first tray to the reference position,
5. The first lifting mechanism according to claim 1, wherein when the second tray is pulled out, the second tray is lowered to the same position as the first tray by the action of gravity. The paper feeder described in the section.
  An image forming apparatus comprising the paper feeding device according to claim 1.

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