Sheet transport device and image forming apparatus

Abstract

To suppress the occurrence of sound caused by movement of a pressure plate during printing of a plurality of sheets.SOLUTION: A sheet conveyance device 500 comprises: a pressure plate 102; a transfer switching mechanism 510; a pressure plate actuation mechanism 520; and a switching mechanism 530 capable of switching a state of the pressure plate actuation mechanism 520. The transfer switching mechanism 510 can switch to a transfer state for transferring drive force of a motor M to a supply roller, and a non-transfer state of not transferring drive force to the supply roller. The pressure plate actuation mechanism 520 can switch to an actuation state for actuating a pressure plate 102 according to drive force of the motor M, and a non-actuation state of not actuating the pressure plate 102 by blocking drive force of the motor M. The transfer switching mechanism 510 switches a state in linkage with the pressure plate actuation mechanism 520. If actuation time of the switching mechanism 530 is a first time, the pressure plate 102 moves, and a state of the transfer switching mechanism is switched. If an actuation time of the switching mechanism 530 is a second time being shorter than the first time, a position of the pressure plate 102 is maintained, and a state of the transfer switching mechanism is switched.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present invention relates to a sheet conveying device and an image forming apparatus including a pressure plate that vertically moves a sheet set on a tray. Background Art

[0002] Conventionally, there has been known a sheet conveying device including a pickup roller for conveying a sheet placed on a manual feed tray, a pressure plate for bringing the sheet on the manual feed tray into pressure contact with or separating from the pickup roller, and a push-up member that vertically moves the pressure plate (see Patent Document 1). In this technology, the operation of pushing up the pressure plate by the push-up member and the rotation operation of the pickup roller for conveying one sheet are performed in conjunction with each other every time one sheet is conveyed. Prior Art Literature Patent Literature

[0003] Patent Document 1 Japanese Unexamined Patent Application Publication No. 2020-104973 Summary of the Invention Problem to be Solved by the Invention

[0004] However, in the conventional technology, when printing a plurality of sheets, the pressure plate moves up and down every time one sheet is conveyed, so there is a problem that noise caused by the vertical movement of the pressure plate is frequently generated.

[0005] Therefore, an object of the present invention is to suppress the generation of noise caused by the movement of the pressure plate when printing a plurality of sheets. Means for Solving the Problem

[0006] In order to solve the above problem, a sheet conveying device according to the present invention includes: a tray; a supply roller; a pressure plate; a motor; a transmission switching mechanism; a pressure plate actuation mechanism; and a switching mechanism. The supply roller transports the sheets that are set in the tray. The pressure plate moves between a contact position where the sheet is in contact with the supply roller and a separation position where the sheet is separated from the supply roller. The transmission switching mechanism can switch between a transmission state in which the motor's driving force is transmitted to the supply roller and a non-transmission state in which the motor's driving force is not transmitted to the supply roller. The pressure plate operating mechanism can be switched between an operating state in which the pressure plate is operated using the driving force of the motor, and a non-operating state in which the pressure plate is not operated by cutting off the driving force of the motor. The switching mechanism can switch the state of the pressure plate operating mechanism. The pressure plate operating mechanism comprises an input gear, a sector gear, a spring, a moving gear, and a gear unit. The input gear is the gear to which the driving force is input. The sector gear has first and second tooth sections that can mesh with the input gear, and first and second missing tooth sections that do not mesh with the input gear, arranged on its outer surface in the order of first missing tooth section, first tooth section, second missing tooth section, and second tooth section. The spring biases the sector gear in the direction of its rotation. The moving gear is movable between a connected position where it receives driving force from the sector gear and a detached position where it does not receive driving force from the sector gear. The gear unit acts on the pressure plate by the driving force transmitted from the moving gear. The gear unit comprises an upstream gear and a downstream gear. The upstream gear meshes with the moving gear located at the coupling position. The downstream gear rotates together with the upstream gear when the upstream gear rotates by more than a first angle. The transmission switching mechanism is configured so that the state switches between a transmission state and a non-transmission state each time the sector gear rotates by a second angle. The switching mechanism comprises a sector lever and a solenoid actuator. The sector lever is rotatable between a rotation-restricting position, where it engages with the sector gear to stop the rotation of the sector gear due to the spring's biasing force, and a rotation-allowing position, where it disengages from the sector gear to allow the sector gear to rotate due to the spring's biasing force. The solenoid actuator moves the sector lever between a rotation-restricted position and a rotation-allowed position. When the sector lever is in the rotation restriction position, the moving gear is in the disengagement position. The moving gear is in the coupling position when the sector lever is in the rotational allowable position. If the operating time of the solenoid actuator, which corresponds to the time it takes to maintain the sector lever in the rotation-permissible position, is the first time, the downstream gear rotates, causing the pressure plate to move, and the sector gear rotates by a second angle, switching the state of the transmission switching mechanism between transmission and non-transmission. If the operating time of the solenoid actuator is shorter than the first time (second time), the position of the pressure plate is maintained because the downstream gear does not rotate, and the state of the transmission switching mechanism is switched between the transmission state and the non-transmission state by the sector gear rotating by a second angle.

[0007] With this configuration, when the pressure plate is in the contact position, activating the solenoid actuator in a second time (shorter than the first time) switches the state of the transmission switching mechanism between transmission and non-transmission while the pressure plate remains in contact. Therefore, when printing multiple sheets, the drive and stop of the supply roller can be switched while maintaining the pressure plate in contact. As a result, when printing multiple sheets, noise generated by the movement of the pressure plate can be suppressed.

[0008] The transmission switching mechanism may also include a planetary gear mechanism, a transmission switching lever, and a cam. The planetary gear mechanism comprises a sun gear, planetary gears, planetary carriers, and internal gears. The transmission switching lever can be switched between a transmission position, which puts the transmission switching mechanism into a transmission state, and a non-transmission position, which puts the transmission switching mechanism into a non-transmission state. In the transmission position, the transmission switching lever engages with the first component, which is one of the three components of the sun gear, planetary carrier, and internal gear. In the non-transmission position, the transmission switching lever disengages from the first component. The cam rotates in conjunction with the sector gear. The cam switches the transmission switching lever between the transmission position and the non-transmission position.

[0009] Furthermore, the pressure plate operating mechanism may include an interlocking gear that rotates together with the sector gear. The interlocking gear can mesh with the moving gear located in the coupling position. The interlocking gear has a cam.

[0010] Furthermore, the interlocking gear may have two toothed portions on its outer surface that can mesh with the moving gear located at the coupling position, and two toothless portions that do not mesh with the moving gear located at the coupling position.

[0011] Furthermore, the input gear may also be one of the three components of the planetary gear mechanism.

[0012] The gear unit may also include a spring that biases the upstream gear toward its initial position.

[0013] The moving gear may also be rotatably supported by the sector lever.

[0014] Furthermore, the sheet conveying device according to the present invention comprises a tray, a supply roller, a pressure plate, a motor, a transmission switching mechanism, a pressure plate operating mechanism, and a solenoid actuator. The supply roller transports the sheets that are set in the tray. The pressure plate moves between a contact position where the sheet is in contact with the supply roller and a separation position where the sheet is separated from the supply roller. The transmission switching mechanism can switch between a transmission state in which the motor's driving force is transmitted to the supply roller and a non-transmission state in which the motor's driving force is not transmitted to the supply roller. The pressure plate actuation mechanism is switchable between an actuation state in which the pressure plate is actuated using the driving force of a motor, and a non-actuation state in which the driving force of the motor is cut off and the pressure plate is not actuated. The solenoid actuator can switch the states of the pressure plate actuation mechanism and the transmission switching mechanism. When the actuation time of the solenoid actuator is a first time, the state of the pressure plate actuation mechanism is switched to the actuation state to move the pressure plate, and the state of the transmission switching mechanism is switched to a transmission state or a non-transmission state. When the actuation time of the solenoid actuator is a second time that is shorter than the first time, the state of the pressure plate actuation mechanism is not switched to the actuation state, the position of the pressure plate is maintained, and the state of the transmission switching mechanism is switched to a transmission state or a non-transmission state.

[0015] According to this configuration, when the solenoid actuator is actuated for a second time shorter than the first time in a state where the pressure plate is positioned at the contact position, the state of the transmission switching mechanism is switched to the transmission state or the non-transmission state while the pressure plate is maintained at the contact position. Therefore, when printing on a plurality of sheets, the driving and stopping of the supply roller can be switched while maintaining the pressure plate at the contact position. Accordingly, when printing on a plurality of sheets, the generation of noise caused by the movement of the pressure plate can be suppressed.

[0016] Further, the tray may be a manual feed tray positioned on a side surface of a main body casing of the image forming apparatus.

[0017] Further, the image forming apparatus according to the present invention includes the sheet conveying device, a main body casing, and a drawer. The main body casing has an opening. A plurality of developing cartridges are attachable to and detachable from the drawer. The drawer is movable through the opening. The supply roller is positioned below the opening. Effects of the Invention

[0018] According to the present invention, when printing multiple sheets, it is possible to suppress the generation of noise caused by the movement of the pressure plate. [Brief explanation of the drawing]

[0019] [Figure 1] This is a diagram showing an image forming apparatus according to the first embodiment. [Figure 2] This figure shows an image forming apparatus with its cover open. [Figure 3] This figure shows an image forming apparatus with the manual feed tray open. [Figure 4] Figure (a) shows a sheet conveying device, and figure (b) shows a cross-sectional view of a planetary gear mechanism. [Figure 5] (a) shows the sheet conveying device as viewed from the sector gear side, and (b) shows it as viewed from the cam side. [Figure 6] Figures 5(a) and 5(b) show the state in which the sector lever has detached from the first projection and the sector gear has rotated, compared to the state in Figures 5(a) and 5(b). [Figure 7] Figures 6(a) and 6(b) show the state after the sector gear has rotated and the upstream gear has rotated relative to the downstream gear, as shown in the states in Figures 6(a) and 6(b). [Figure 8] Figures 7(a) and 7(b) show the state after the sector gear has rotated and the downstream gear has rotated together with the upstream gear, compared to the state shown in Figures 7(a) and 7(b). [Figure 9] Figure 5(a) shows the state in which the sector gear has rotated 180° from the state in Figure 5(a) and the second projection of the sector lever is stopped by the sector lever, and Figure 5(b) shows the state in which the transmission switching lever has been switched to the transmission position. [Figure 10] Figures 9(a) and 9(b) show the state in which the sector lever has detached from the second projection and the sector gear has rotated, compared to the state in Figures 9(a) and 9(b). [Figure 11] Figure 10(a) shows the state after the sector gear has rotated from the state shown in Figure 10(a), and Figure 10(b) shows the state after the transmission switching lever has been switched to the non-transmission position. [Figure 12]Figure (a) shows the state in which the linkage between the interlocking gear and the moving gear is broken and the upstream gear returns to its initial position, and Figure (b) shows the state of the transmission switching lever. [Figure 13] Figure (a) shows the sheet conveying device according to the second embodiment as viewed from the sector gear side, and Figure (b) shows it as viewed from the cam side. [Modes for carrying out the invention]

[0020] [First Embodiment] Next, a first embodiment of the present invention will be described in detail with reference to the drawings as appropriate. As shown in Figure 1, the image forming apparatus 1 is a color printer. The image forming apparatus 1 comprises a main body housing 10, a cover 11, a supply unit 20, an image forming unit 30, and an output unit 90.

[0021] The main casing 10 has an opening 10A. The cover 11 opens and closes the opening 10A.

[0022] The supply unit 20 is located in the lower part of the main body housing 10. The supply unit 20 includes a sheet tray 21 for holding sheets S and a first supply mechanism 22 for supplying sheets S from the sheet tray 21 to the image forming unit 30. The sheet tray 21 is configured to be removable by pulling it out from the main body housing 10. The first supply mechanism 22 includes a first pickup roller 23, a first separation roller 24, a first separation pad 25, and a registration roller 26. The sheet S is a medium on which the image forming apparatus 1 can form an image, and includes plain paper, envelopes, postcards, thin paper, thick paper, glossy paper, resin sheets, seals, etc.

[0023] In the supply unit 20, after the sheets S in the sheet tray 21 are fed out by the first pickup roller 23, the sheets S are separated one by one between the first separation roller 24 and the first separation pad 25. Then, the leading edge position of the sheets S is restricted by the registration roller 26, which is in a stopped state, and then the registration roller 26 rotates to supply the sheets S to the image forming unit 30.

[0024] The image forming unit 30 has the function of forming an image on the sheet S. The image forming unit 30 comprises a scanner unit 40, a drawer 50, a transfer unit 70, and a fixing unit 80.

[0025] The scanner unit 40 is located at the top of the main body housing 10 and includes a laser light-emitting unit (not shown), a polygon mirror, a lens, and a reflector. The scanner unit 40 exposes the surface of each photosensitive drum 51 of the drawer 50 with a laser beam.

[0026] The drawer 50 is movable through the opening 10A between the storage position shown in Figure 1 and the pull-out position shown in Figure 2. The drawer 50 includes four photosensitive drums 51 and four developing cartridges 52.

[0027] Each photosensitive drum 51 is attached to a drawer 50. Although not shown in the diagram, the drawer 50 also has a charger and other components attached to it in addition to the photosensitive drums 51.

[0028] Each developing cartridge 52 is detachable from the drawer 50. The developing cartridge 52 has a developing roller 53 that supplies toner to the photosensitive drum 51. The developing cartridge 52 contains toner inside.

[0029] The transfer unit 70 is located between the supply unit 20 and the drawer 50. The transfer unit 70 includes a drive roller 71, a driven roller 72, a conveyor belt 73, and a transfer roller 74.

[0030] The drive roller 71 and driven roller 72 are rollers for rotating the conveyor belt 73. The outer surface of the conveyor belt 73 is in contact with the photosensitive drum 51. In addition, four transfer rollers 74 are arranged on the inside of the conveyor belt 73 to sandwich the conveyor belt 73 between itself and the photosensitive drum 51.

[0031] The fixing unit 80 includes a heating roller 81 and a pressure roller 82. The pressure roller 82 sandwiches the sheet S between itself and the heating roller 81.

[0032] In the image forming unit 30, first, the surface of the photosensitive drum 51 is uniformly charged by a charger, and then exposed by the scanner unit 40. This forms an electrostatic latent image on the photosensitive drum 51. Subsequently, the developing roller 53 supplies toner to the electrostatic latent image on the photosensitive drum 51. This forms a toner image on the photosensitive drum 51.

[0033] Next, the sheet S supplied onto the conveyor belt 73 passes between the photosensitive drum 51 and the transfer roller 74, transferring the toner image on the photosensitive drum 51 to the sheet S. Then, the sheet S passes between the heating roller 81 and the pressure roller 82, thermally fixing the toner image to the sheet S.

[0034] The discharge unit 90 discharges the sheet S on which the image has been formed. The discharge unit 90 is equipped with a plurality of transport rollers 91 for transporting the sheet S. The sheet S on which the toner image has been heat-fixed is transported by the transport rollers 91 and discharged to the outside of the main body housing 10.

[0035] As shown in Figure 4(a), the image forming apparatus 1 further comprises a sheet transport device 500 and a control unit CT. The sheet transport device 500 comprises a manual feed tray 101, a pressure plate 102 and a second supply mechanism 110 as shown in Figure 3, and a motor M, a push-up member 580, a transmission switching mechanism 510, a pressure plate operating mechanism 520 and a switching mechanism 530 as shown in Figure 4(a).

[0036] As shown in Figure 3, the manual feed tray 101 is an example of a tray into which the sheet S is set. The manual feed tray 101 is located on the side of the main housing 10. The manual feed tray 101 is rotatably attached to the cover 11. The manual feed tray 101 is rotatable between the closed position shown in Figure 1 and the open position shown in Figure 3.

[0037] As shown in Figure 3, the cover 11 has an opening 11A through which the sheet S can pass. When the manual feed tray 101 is in the closed position, it closes the opening 11A. When the manual feed tray 101 is in the open position, it opens the opening 11A.

[0038] The pressure plate 102 is movable between a contact position shown by a solid line in the figure and a separation position shown by a dashed line. Specifically, the pressure plate 102 is rotatable relative to the manual feed tray 101 and can rotate between the contact position and the separation position. Here, the contact position changes depending on the number of sheets S on the pressure plate 102.

[0039] When the pressure plate 102 is in the contact position, it brings the sheet S on the manual feed tray 101 into contact with the second pickup roller 111, which will be described later. When the pressure plate 102 is in the separated position, it separates the sheet S on the manual feed tray 101 from the second pickup roller 111.

[0040] The second supply mechanism 110 includes a second pickup roller 111 as an example of a supply roller, a second separation roller 112, a second separation pad 113, a holder 114, and a spring 115.

[0041] The second pickup roller 111 is a roller for transporting the sheet S on the manual feed tray 101. The second pickup roller 111 is located below the opening 10A of the main housing 10.

[0042] The second separation roller 112 and the second separation pad 113 have the function of separating the sheets S fed out from the second pickup roller 111 into individual sheets. The second separation roller 112 conveys the sheets S toward the registration roller 26.

[0043] The second pickup roller 111 and the second separation roller 112 are rotatably mounted on a holder 114. The holder 114 is rotatably mounted on the main housing 10. The holder 114 rotates, for example, around the rotation axis of the second separation roller 112.

[0044] The spring 115 is located between the main housing 10 and the holder 114. The spring 115 biases the second pickup roller 111 toward the pressure plate 102.

[0045] As shown in Figure 4(a), the push-up member 580 is a member that pushes the pressure plate 102 from a separated position to a contact position. The push-up member 580 has a push-up gear 581 and a push-up cam 582.

[0046] The push-up gear 581 is a gear that receives driving force from the motor M via the pressure plate operating mechanism 520. The push-up cam 582 is a cam that rotates together with the push-up gear 581. The push-up cam 582 can be switched between a spaced-out position, shown by a solid line in the figure, and a contact position, shown by a dashed-dot line.

[0047] The push-up cam 582 has a contact portion 582A that contacts the pressure plate 102 when the pressure plate 102 is in the contact position. The contact portion 582A may be located within the range of the second pickup roller 111 in the width direction of the sheet S, or it may be located outside the range of the second pickup roller 111. Here, the width direction of the sheet S is the same direction as the axial direction of the second pickup roller 111.

[0048] The transmission switching mechanism 510 is a mechanism that can switch between a transmission state in which the driving force of the motor M is transmitted to the second pickup roller 111 and a non-transmission state in which the driving force of the motor M is not transmitted to the second pickup roller 111. The transmission switching mechanism 510 comprises a planetary gear mechanism 540, a transmission switching lever Lt, and a cam 511.

[0049] As shown in Figures 4(a) and 4(b), the planetary gear mechanism 540 comprises a sun gear 541, a plurality of planetary gears 542, a planetary carrier 543 as an example of a first component, and an internal gear 544. The planetary gear mechanism 540 is structured such that if the rotation of one of the three components—the sun gear 541, the planetary carrier 543, and the internal gear 544—is stopped, the remaining components rotate in conjunction.

[0050] The sun gear 541 is a two-stage gear. The sun gear 541 has a large-diameter gear section 541A and a small-diameter gear section 541B which has a smaller diameter than the large-diameter gear section 541A.

[0051] Multiple planetary gears 542 are arranged around the small-diameter gear section 541B and mesh with the small-diameter gear section 541B. The multiple planetary gears 542 are rotatably mounted on the planetary carrier 543.

[0052] The planetary carrier 543 is rotatable around the axis of rotation of the sun gear 541. The planetary carrier 543 has a plurality of claws 543A on its outer surface.

[0053] The internal gear 544 is a ring-shaped member. The internal gear 544 has internal teeth 544A located on its inner circumferential surface and external teeth 544B located on its outer circumferential surface. The internal teeth 544A mesh with the planetary gear 542. For convenience, the internal teeth 544A of the internal gear 544 and the planetary gear 542 are not shown in Figure 4(a) and Figure 5(a) described later.

[0054] The external teeth 544B of the internal gear 544 mesh with the gear G51 to which the driving force of the motor M is input. In this embodiment, the internal gear 544 is an example of an input gear to which the driving force of the motor M is input. The internal gear 544 and the motor M may be directly connected or indirectly connected via multiple gears. Similarly, the connection between other gears may be direct or indirect.

[0055] The large-diameter gear section 541A of the sun gear 541 meshes with gear G52, which outputs driving force to the second separation roller 112 and the second pickup roller 111.

[0056] When the rotation of the planetary carrier 543 is stopped, the driving force from the motor M is transmitted to the second separation roller 112 and the second pickup roller 111 via the planetary gear mechanism 540. When the rotation of the planetary carrier 543 is permitted, the gear G52, etc., acts as a resistance to the rotation of the sun gear 541, stopping the rotation of the sun gear 541. As a result, the driving force from the motor M is transmitted to the planetary carrier 543, causing the planetary carrier 543 to spin freely. In other words, when the rotation of the planetary carrier 543 is permitted, the driving force from the motor M is not transmitted to the second pickup roller 111, and the second pickup roller 111 does not rotate.

[0057] The transmission switching lever Lt is a lever for stopping or allowing the rotation of the planetary carrier 543. The transmission switching lever Lt is rotatable between the transmission position shown in Figure 9(b) and the non-transmission position shown in Figure 5(b). When the transmission switching lever Lt is in the transmission position, it catches on the claw 543A of the planetary carrier 543, stopping the rotation of the planetary carrier 543. As a result, when the transmission switching lever Lt is in the transmission position, the transmission switching mechanism 510 is put into the transmission state.

[0058] When the transmission switching lever Lt is in the non-transmission position, it disengages from the claw 543A of the planetary carrier 543, thereby allowing the planetary carrier 543 to rotate. As a result, when the transmission switching lever Lt is in the non-transmission position, the transmission switching mechanism 510 is put into a non-transmission state. The transmission switching lever Lt is biased from the non-transmission position toward the transmission position by a spring (not shown).

[0059] Cam 511 is a cam for switching the transmission switching lever Lt between the transmission position and the non-transmission position. As shown in Figure 5(b), cam 511 has a cam surface F1 and a retracted surface F2.

[0060] The cam surface F1 is a cylindrical surface centered on the rotation axis of the sector gear 550. The cam surface F1 can contact the transmission switching lever Lt. The retracted surface F2 is retracted further towards the rotation axis of the sector gear 550 than the cam surface F1.

[0061] When the cam 511 rotates from the state shown in Figure 9(b) and the cam surface F1 comes into contact with the transmission switching lever Lt, the cam surface F1 moves the transmission switching lever Lt from the transmission position to the non-transmission position against the biasing force of the spring. When the cam 511 rotates from the state shown in Figure 5(b) and the transmission switching lever Lt disengages from the cam surface F1, and the retracted surface F2 faces the transmission switching lever Lt, the transmission switching lever Lt moves from the non-transmission position to the transmission position due to the biasing force of the spring.

[0062] The cam 511 rotates in conjunction with the sector gear 550 of the pressure plate operating mechanism 520, which will be described later. More specifically, the cam 511 rotates together with the sector gear 550 around the rotation axis of the sector gear 550.

[0063] As will be described later, the sector gear 550 is configured to rotate in 180° increments, which is an example of a second angle. As a result, the cam 511 is switched to the position shown in Figure 9(b) or Figure 5(b) each time the sector gear 550 rotates 180°, and the transmission switching lever Lt is switched to the transmission position or the non-transmission position. Therefore, the transmission switching mechanism 510 is configured so that its state switches between the transmission state and the non-transmission state each time the sector gear 550 rotates 180°.

[0064] As shown in Figure 4(a), the pressure plate operating mechanism 520 is a mechanism that can switch between an operating state in which the pressure plate 102 is operated using the driving force of the motor M, and a non-operating state in which the pressure plate 102 is not operated by cutting off the driving force of the motor M. The pressure plate operating mechanism 520 comprises the internal gear 544, sector gear 550, interlocking gear 560, spring 521, moving gear 522, gear unit 570, and push-up member 580.

[0065] As shown in Figure 5(a), the sector gear 550 has a first tooth portion 551, a second tooth portion 552, a first missing tooth portion 553, and a second missing tooth portion 554 on its outer circumferential surface. The first tooth portion 551 and the second tooth portion 552 are portions that can mesh with the external teeth 544B of the internal gear 544. The first missing tooth portion 553 and the second missing tooth portion 554 are portions that cannot mesh with the external teeth 544B of the internal gear 544. On the outer circumferential surface of the sector gear 550, the first tooth portion 551, the first tooth portion 551, the second missing tooth portion 554, and the second missing tooth portion 552 are arranged in that order.

[0066] More specifically, the teeth are arranged in the following order from the first missing tooth portion 553 toward the upstream side in the rotational direction of the sector gear 550 (see Figure 6): the first tooth portion 551, the second missing tooth portion 554, and the second tooth portion 552. Here, the rotational direction of the sector gear 550 refers to the direction of rotation of the sector gear 550 when it receives driving force from the internal gear 544, which is the clockwise direction in the figure.

[0067] In the rotational direction of the sector gear 550, the first missing tooth portion 553 is located upstream of the second tooth portion 552. In the rotational direction of the sector gear 550, the first tooth portion 551 is located upstream of the first missing tooth portion 553. In the rotational direction of the sector gear 550, the second missing tooth portion 554 is located upstream of the first tooth portion 551. In the rotational direction of the sector gear 550, the second tooth portion 552 is located upstream of the second missing tooth portion 554.

[0068] The sector gear 550 has a first projection 555, a second projection 556, and a spring contact portion 557. The first projection 555, the second projection 556, and the spring contact portion 557 protrude from one side of the sector gear 550 in the axial direction. The first projection 555 and the second projection 556 are projections on which the sector lever Ls, described later, can catch.

[0069] When the sector lever Ls is caught on the first projection 555, the first missing tooth portion 553 faces the internal gear 544, and no driving force is transmitted from the internal gear 544 to the sector gear 550. As shown in Figure 9(a), when the sector lever Ls is caught on the second projection 556, the second missing tooth portion 554 faces the internal gear 544, and no driving force is transmitted from the internal gear 544 to the sector gear 550.

[0070] As shown in Figure 4(a), the spring contact portion 557 is the portion that the spring 521 contacts. The spring 521 is a spring that biases the sector gear 550 in the rotational direction of the sector gear 550. The spring 521 is, for example, a torsion spring. One end of the spring 521 contacts the spring contact portion 557. The other end of the spring 521 contacts a part 13 of the main housing 10.

[0071] The interlocking gear 560 is a gear that rotates together with the sector gear 550. The interlocking gear 560 is fixed to or integrally formed with the other axial side of the sector gear 550. As shown in Figure 5(b), the interlocking gear 560 has the aforementioned cam 511 on the side opposite to the side where the sector gear 550 is located. The cam 511 is fixed to or integrally formed with the interlocking gear 560.

[0072] As shown in Figure 5(a), the interlocking gear 560 has a third tooth portion 561, a fourth tooth portion 562, a third missing tooth portion 563, and a fourth missing tooth portion 564 on its outer circumferential surface. The third tooth portion 561 and the fourth tooth portion 562 are portions that can mesh with the moving gear 522 located at the coupling position (position indicated by the dashed line), which will be described later. The number of teeth on the third tooth portion 561 and the fourth tooth portion 562 is such that the downstream gear 572, which will be described later, can be rotated by 180°. More specifically, the number of teeth on the third tooth portion 561 and the fourth tooth portion 562 is such that the upstream gear 571, which will be described later, can be rotated by an angle equal to the first angle plus 180°.

[0073] The third tooth portion 563 and the fourth tooth portion 564 are parts that cannot mesh with the moving gear 522 located in the coupling position. The third tooth portion 561, the fourth tooth portion 562, the third tooth portion 563, and the fourth tooth portion 564 are arranged on the outer circumferential surface of the interlocking gear 560 in the order of third tooth portion 563, third tooth portion 561, fourth tooth portion 564, and fourth tooth portion 562.

[0074] More specifically, the teeth are arranged in the following order from the third missing tooth portion 563 toward the upstream side in the rotational direction of the interlocking gear 560: the third tooth portion 561, the fourth missing tooth portion 564, and the fourth tooth portion 562. Here, the rotational direction of the interlocking gear 560 is the same as the rotational direction of the sector gear 550.

[0075] In the rotational direction of the interlocking gear 560, the third missing tooth portion 563 is located upstream of the fourth tooth portion 562. In the rotational direction of the interlocking gear 560, the third tooth portion 561 is located upstream of the third missing tooth portion 563. In the rotational direction of the interlocking gear 560, the fourth missing tooth portion 564 is located upstream of the third tooth portion 561. In the rotational direction of the interlocking gear 560, the fourth tooth portion 562 is located upstream of the fourth missing tooth portion 564.

[0076] When the sector lever Ls is engaged with the first projection 555, the third missing tooth portion 563 faces the moving gear 522. As shown in Figure 9(a), when the sector lever Ls is engaged with the second projection 556, the fourth missing tooth portion 564 faces the moving gear 522.

[0077] As shown in Figure 5(a), the movable gear 522 is movable between the connected position, shown by the dashed line in the figure, and the disengaged position, shown by the solid line. When the movable gear 522 is in the connected position, it is possible for it to mesh with the third tooth 561 or the fourth tooth 562 of the interlocking gear 560. As a result, when the movable gear 522 is in the connected position, it is possible for it to receive driving force from the sector gear 550.

[0078] When the moving gear 522 is in the disengaged position, it cannot engage with the third tooth 561 or the fourth tooth 562 of the interlocking gear 560. As a result, when the moving gear 522 is in the disengaged position, it cannot receive driving force from the sector gear 550. The moving gear 522 is rotatably supported by the sector lever Ls, which will be described later.

[0079] The gear unit 570 has the function of operating the pressure plate 102 by the driving force transmitted from the moving gear 522. More specifically, the gear unit 570 operates the pressure plate 102 by transmitting the driving force transmitted from the moving gear 522 to the push-up member 580.

[0080] The gear unit 570 comprises an upstream gear 571, a downstream gear 572, and a spring 573. The upstream gear 571 meshes with the moving gear 522, which is located in the coupling position. In this embodiment, the upstream gear 571 also meshes with the moving gear 522 when the moving gear 522 is in the disengaged position.

[0081] The upstream gear 571 has two grooves 571A. Each groove 571A is formed in an arc shape centered on the pivot axis of the upstream gear 571. The two grooves 571A are point-symmetric with respect to the pivot axis of the upstream gear 571.

[0082] The downstream gear 572 is a gear that rotates together with the upstream gear 571 when the upstream gear 571 rotates by a first angle or more. Here, the first angle is an angle less than 180°, and in this embodiment, it is an angle less than 90°.

[0083] The downstream gear 572 has two projections 572A. The projections 572A fit into grooves 571A of the upstream gear 571. Specifically, one projection 572A fits into one groove 571A, and the other projection 572A fits into the other groove 571A.

[0084] One projection 572A is separated from the upstream end E1 of one groove 571A in the rotational direction of the upstream gear 571. Here, the rotational direction of the upstream gear 571 is the direction in which the upstream gear 571 rotates due to the driving force of the motor M. The other projection 572A is separated from the upstream end E1 of the other groove 571A in the rotational direction of the upstream gear 571.

[0085] Spring 573 is a spring that biases the upstream gear 571 toward its initial position. Here, the initial position refers to the position of the upstream gear 571 when the driving force of the motor M is not input to the upstream gear 571. The initial position when the pressure plate 102 is in the separated position is the position shown in Figure 5(a). The initial position when the pressure plate 102 is in the contact position is the position shown in Figure 9(a), that is, the position rotated 180° from the position shown in Figure 5(a).

[0086] There is one spring 573 in one groove 571A and one in the other groove 571A. One spring 573 is located between one projection 572A and the upstream end E1 of one groove 571A. The other spring 573 is located between the other projection 572A and the upstream end E1 of the other groove 571A.

[0087] The downstream gear 572 receives driving force from the upstream gear 571 via a spring 573. Specifically, as shown in Figure 7, when the upstream gear 571 rotates within a range of less than a first angle from its initial position, the spring 573 is simply compressed between the upstream gear 571 and the downstream gear 572, and the downstream gear 572 does not rotate. As shown in Figure 8, when the upstream gear 571 rotates by more than a first angle from its initial position, the upstream gear 571 pushes the downstream gear 572 via the spring 573, causing the downstream gear 572 to rotate together with the upstream gear 571.

[0088] When all the teeth of the third tooth section 561 or the fourth tooth section 562 of the interlocking gear 560 push against the teeth of the moving gear 522, the downstream gear 572 rotates 180°. The downstream gear 572 is meshed with the push-up gear 581. Therefore, each time the downstream gear 572 rotates 180°, the push-up member 580 also rotates 180°.

[0089] As shown in Figure 4(a), the switching mechanism 530 is a mechanism for switching the state of the pressure plate operating mechanism 520. The switching mechanism 530 comprises a sector lever Ls, a solenoid actuator SA, and a spring 531.

[0090] The sector lever Ls is rotatable between a rotation restriction position shown by a solid line in the figure and a rotation allowance position shown by a dashed line. When the sector lever Ls is in the rotation restriction position, it catches on the first projection 555 or the second projection 556 of the sector gear 550, thereby stopping the rotation of the sector gear 550 due to the biasing force of the spring 521. When the sector lever Ls is in the rotation allowance position, it disengages from the first projection 555 or the second projection 556 of the sector gear 550, thereby allowing the rotation of the sector gear 550 due to the biasing force of the spring 521.

[0091] One end of the sector lever Ls engages with the first projection 555 or the second projection 556. The other end of the sector lever Ls rotatably supports the moving gear 522. The pivot axis of the sector lever Ls is located between the one end and the other end of the sector lever Ls.

[0092] When the sector lever Ls is in the rotation-restricting position, the moving gear 522 is in the disengaged position. When the sector lever Ls is in the rotation-permitted position, the moving gear 522 is in the coupled position.

[0093] The solenoid actuator SA is an actuator for moving the sector lever Ls between a rotation-restricting position and a rotation-allowing position. The solenoid actuator SA has a retractable piston SA1. The piston SA1 is engaged with the sector lever Ls. The piston SA1 is movable between the forward position shown in the figure and the retracted position not shown.

[0094] The spring 531 biases the sector lever Ls from the rotation-permitted position to the rotation-restricted position.

[0095] When the solenoid actuator SA is energized, it activates, causing the piston SA1 to move from the forward position to the reverse position, pulling the sector lever Ls. This causes the sector lever Ls to move from the rotation-restricted position to the rotation-allowed position against the biasing force of the spring 531.

[0096] When the power supply to the solenoid actuator SA is cut off, the piston SA1 moves from the retracted position to the forward position. As a result, the sector lever Ls moves from the rotation-allowed position to the rotation-restricted position due to the biasing force of the spring 531.

[0097] As shown in Figure 4(a), the control unit CT has a CPU, ROM, RAM, non-volatile memory, etc., and is configured to perform various controls based on a pre-prepared program. When printing multiple sheets S, the control unit CT has the function of transporting multiple sheets S by moving the pressure plate 102 from a separated position to a contact position, and then intermittently driving the second pickup roller 111 without moving the pressure plate 102 from the contact position.

[0098] The operation of the control unit CT is described in detail below. Note that when the control unit CT is not receiving a print command, the positions of each component are as shown in Figure 4(a).

[0099] When the control unit CT receives a print command to print multiple sheets S, it first rotates the motor M. This causes the gear G51, internal gear 544, and planetary carrier 543 to rotate.

[0100] Subsequently, the control unit CT energizes the solenoid actuator SA, and when the solenoid actuator SA is activated, the sector lever Ls rotates from the rotation-restricted position to the rotation-allowed position, as shown in Figure 6(a). As a result, the sector lever Ls disengages from the first projection 555 of the sector gear 550, and the moving gear 522 moves from the disengaged position to the coupled position.

[0101] When the control unit CT first energizes the solenoid actuator SA after receiving a print command, the energizing time is set to the first time required to move the pressure plate 102 from the separated position to the contact position. As a result, the operating time of the solenoid actuator SA becomes the first time, and the sector lever Ls is maintained in the rotation-permissible position for the duration of the first time.

[0102] When the sector lever Ls disengages from the first projection 555, the biasing force of the spring 521 shown in Figure 4(a) causes the sector gear 550, the interlocking gear 560, and the cam 511 to rotate, as shown in Figures 6(a) and (b). As a result, the first teeth 551 of the sector gear 550 mesh with the internal gear 544, and the third teeth 561 of the interlocking gear 560 mesh with the moving gear 522 located in the coupling position.

[0103] In this embodiment, the first timing at which the first tooth portion 551 engages with the internal gear 544 and the second timing at which the third tooth portion 561 engages with the moving gear 522 are set to be approximately simultaneous. However, it is acceptable for the second timing to be later than the first timing.

[0104] When the sector gear 550 is connected to the internal gear 544 and the interlocking gear 560 is connected to the moving gear 522, the driving force of the motor M is transmitted from the internal gear 544 to the moving gear 522 via the sector gear 550 and the interlocking gear 560. As a result, the moving gear 522 and the upstream gear 571 rotate.

[0105] As the upstream gear 571 rotates, the spring 573 is compressed between the upstream gear 571 and the downstream gear 572, as shown in Figure 7(a). During this time, the downstream gear 572 does not move.

[0106] When the upstream gear 571 rotates by more than a first angle from its initial position, as shown in Figure 8(a), the upstream gear 571 pushes the downstream gear 572 via the spring 573, causing the downstream gear 572 to rotate together with the upstream gear 571. As the downstream gear 572 rotates, the push-up member 580 rotates from the spaced-out position towards the contact position, causing the pressure plate 102 to rotate from the spaced-out position towards the contact position.

[0107] When the third tooth 561 of the interlocking gear 560 disengages from the moving gear 522, which is located in the coupling position, the downstream gear 572 stops at a position rotated 180° from its initial position, as shown in Figure 9(a). As a result, the push-up member 580 stops at the contact position, and the pressure plate 102 is maintained in the contact position.

[0108] Furthermore, when the third tooth 561 of the interlocking gear 560 disengages from the moving gear 522, the biasing force of the spring 573 causes the upstream gear 571 to rotate relative to the stationary downstream gear 572, moving it to its initial position.

[0109] The control unit CT stops supplying power to the solenoid actuator SA after 1 hour has elapsed since the start of power supply. This 1 hour is set to be longer than the time it takes for the downstream gear 572 to rotate 180° from its initial position, from the start of power supply to the solenoid actuator SA.

[0110] When the power supply to the solenoid actuator SA is cut off, the sector lever Ls rotates from the rotation-allowed position to the rotation-restricted position. This allows the sector lever Ls to engage with the second projection 556 of the sector gear 550, and the moving gear 522 moves from the coupled position to the disengaged position.

[0111] When the first tooth 551 of the sector gear 550 disengages from the internal gear 544, the driving force of the motor M is no longer transmitted to the sector gear 550, but the sector gear 550 rotates due to the biasing force of the spring 521. As a result, the second projection 556 of the sector gear 550 engages with the sector lever Ls, which is located in the rotation-restricting position, and the rotation of the sector gear 550 is stopped. In other words, the sector gear 550 stops at a position rotated 180° from the position shown in Figure 5(a).

[0112] As the sector gear 550 rotates 180°, the cam 511 also rotates 180°, as shown in Figures 5 to 9(b). This causes the cam surface F1 of the cam 511 to disengage from the transmission switching lever Lt, so that the transmission switching lever Lt moves from the non-transmission position to the transmission position. This switches the state of the transmission switching mechanism 510 from the non-transmission state to the transmission state.

[0113] When the transmission switching lever Lt moves from the non-transmission position to the transmission position, the rotation of the planetary carrier 543 is stopped. As a result, the sun gear 541 rotates together with the internal gear 544, causing the second pickup roller 111 to rotate and the transport of the first sheet S to begin.

[0114] The control unit CT, in order to transport the sheet S to the registration roller 26 by the rotating second pickup roller 111, stops supplying power to the solenoid actuator SA, and then, after a predetermined time, supplies power to the solenoid actuator SA for a second time. Here, the second time is the time during which the upstream gear 571 does not rotate by more than a first angle, and is shorter than the first time.

[0115] When the solenoid actuator SA is operating for the second time, as shown in Figures 10 to 12(a), the moving gear 522 is in the coupled position for the second time and then moves to the disengaged position. As a result, the driving force of the motor M is transmitted to the upstream gear 571 for the second time, so the upstream gear 571 rotates by a small angle less than the first angle and then returns to its initial position due to the biasing force of the spring 573. Therefore, when the solenoid actuator SA is operating for the second time, the downstream gear 572 does not rotate. This maintains the position of the pressure plate 102 in the contact position.

[0116] On the other hand, the sector gear 550 also stops after rotating 180° even when the operating time of the solenoid actuator SA is the second time. Specifically, after the sector lever Ls disengages from the second projection 556, the sector gear 550 rotates 180° due to the biasing force of the spring 521 and the driving force from the internal gear 544, and then stops when the first projection 555 catches on the sector lever Ls. As a result, as shown in Figures 10 to 12(b), the cam surface F1 of the cam 511 pushes the transmission switching lever Lt, so that the transmission switching lever Lt moves from the transmission position to the non-transmission position, and the state of the transmission switching mechanism 510 is switched from the transmission state to the non-transmission state.

[0117] Subsequently, the control unit CT performs a short-time energizing process, which energizes the solenoid actuator SA for a second time, a number of times corresponding to the remaining sheets S. Specifically, to transport one sheet S, the control unit CT performs the short-time energizing process twice, switching the state of the transmission switching mechanism 510 from a non-transmission state to a transmission state, and then from a transmission state to a non-transmission state. The interval between the two short-time energizing processes corresponding to one sheet S is set to correspond to the time required to transport one sheet S to the registration roller 26.

[0118] When transporting the last sheet S, the control unit CT performs a short-time energizing process once, followed by a long-time energizing process that energizes the solenoid actuator SA for 1 hour. As a result, the short-time energizing process maintains the position of the pressure plate 102 in contact with the start of sheet S transport, and the long-time energizing process stops the rotation of the second pickup roller 111 and returns the position of the pressure plate 102 to the separated position.

[0119] In other words, when printing multiple sheets S, the control unit CT performs a long-duration power application on the first sheet S, followed by a short-duration power application, to move the pressure plate 102 to the contact position and transport the first sheet S. When printing the remaining sheets S, excluding the last sheet S, the control unit CT performs two short-duration power applications on each sheet S, maintaining the pressure plate 102 in the contact position while transporting the sheets S one by one. When printing the last sheet S, the control unit CT performs a short-duration power application, followed by a long-duration power application, to transport the last sheet S and then move the pressure plate 102 to the separated position.

[0120] As described above, the following effects can be obtained according to this embodiment. When the pressure plate 102 is in the contact position, if the solenoid actuator SA is activated for a second time shorter than the first time, the state of the transmission switching mechanism 510 is switched between a transmission state and a non-transmission state while the pressure plate 102 is maintained in the contact position. Therefore, when printing multiple sheets S, the drive and stop of the second pickup roller 111 can be switched while maintaining the pressure plate 102 in the contact position, thus suppressing the generation of noise caused by the movement of the pressure plate 102 when printing multiple sheets S.

[0121] [Second Embodiment] Next, a second embodiment of the present invention will be described in detail with reference to the drawings as appropriate. Since this embodiment is a modification of the gear unit 570 in the first embodiment, components substantially the same as those in the first embodiment are denoted by the same reference numerals, and their descriptions are omitted.

[0122] As shown in Figure 13, the upstream gear 571 of the gear unit 570 according to the second embodiment is positioned to mesh with the moving gear 522 in the connected position, but not with the moving gear 522 in the disengaged position. According to the second embodiment, the moving gear 522 can be moved smoothly.

[0123] The present invention is not limited to the embodiments described above, and can be used in various forms as illustrated below.

[0124] The tray is not limited to a manual feed tray; for example, it could be a sheet tray. Also, the supply roller could be a first pickup roller.

[0125] The pressure plate and moving gear may be movable in a straight line.

[0126] The sector lever and the moving gear may be moved by separate drive sources. In this case, the control unit may drive the first drive source to move the sector lever to a rotation-permitted position and the second drive source to move the moving gear to a coupled position. Alternatively, the control unit may drive the first drive source to move the sector lever to a rotation-restricted position and the second drive source to move the moving gear to a disengaged position.

[0127] The transmission switching lever only needs to be switchable between a transmission position and a non-transmission position, and may, for example, be moved in a straight line.

[0128] The first component of the planetary gear mechanism into which the transmission switching lever engages may be a sun gear or an internal gear.

[0129] The cam and sector gear do not have to be a single unit; they may be separate components. In this case, for example, the cam and sector gear may be directly connected by gear teeth, or indirectly connected via a predetermined number of gears.

[0130] The interlocking gear and the sector gear do not have to be a single unit; they may be separate components. In this case, for example, the interlocking gear and the sector gear may be directly connected by gear teeth, or indirectly connected via a predetermined number of gears.

[0131] The transmission switching mechanism may be, for example, a pendulum gear. In this case, the pendulum gear is rotatable between a transmission position in which the motor's driving force is transmitted to the supply roller and a non-transmission position in which the motor's driving force is not transmitted to the supply roller. Furthermore, the pendulum gear is switched between the transmission position and the non-transmission position each time the sector gear rotates by a second angle.

[0132] The second angle is not limited to 180°; for example, it may be 120° or 90°. If the second angle is 120°, the sector gear may have three teeth and missing teeth. If the second angle is 90°, the sector gear may have four teeth and missing teeth.

[0133] The pressure plate operating mechanism is not limited to the structure of the embodiment described above, but may have any structure.

[0134] In the above embodiment, the state of the pressure plate operating mechanism and the transmission switching mechanism were switched by the sector lever Ls, solenoid actuator SA, cam 511, and transmission switching lever Lt, but the present invention is not limited thereto. Any structure is acceptable as long as the state of the pressure plate operating mechanism and the transmission switching mechanism can be switched using a solenoid actuator. Specifically, when the operating time of the solenoid actuator is 1 time, the state of the pressure plate operating mechanism is switched to the operating state and the pressure plate moves, and the state of the transmission switching mechanism is switched to the transmission state or non-transmission state, and when the operating time of the solenoid actuator is 2 time, which is shorter than the 1 time, the state of the pressure plate operating mechanism is not switched to the operating state and the position of the pressure plate is maintained, and the state of the transmission switching mechanism is switched to the transmission state or non-transmission state.

[0135] Interlocking gears are not necessarily required. In this case, for example, the moving gear may be made movable between a connected position where it meshes with the sector gear and a disengaged position where it is disengaged from the sector gear.

[0136] The input gear is not limited to an internal gear; for example, it may be a gear that meshes directly or indirectly with the internal gear in the above embodiment.

[0137] The spring is not limited to the above embodiment; it may be a wire spring, a leaf spring, or any other type of spring.

[0138] The elements described in the above embodiments and modifications may be implemented in any combination. [Explanation of symbols]

[0139] 101 Manual Feed Tray 102 Pressure plate 111 Second Pickup Roller 500 Sheet Conveyor System 510 Transmission switching mechanism 520 Pressure plate operating mechanism 521 Spring 522 Movement gear 530 Switching mechanism 544 Internal gear 550 Sector Gear 551 1st tooth part 552 2nd tooth part 553 1st missing tooth part 554 2nd missing tooth part 570 Gear Unit 571 Upstream gear 572 Downstream gear Ls Sector Lever M Motor S Seat SA Solenoid Actuator

Claims

1. A tray and A supply roller for transporting the sheet set in the tray, A pressure plate that moves between a contact position in which the sheet is in contact with the supply roller and a separation position in which the sheet is separated from the supply roller, Motor and, A transmission switching mechanism that can switch between a transmission state in which the driving force of the motor is transmitted to the supply roller and a non-transmission state in which the driving force of the motor is not transmitted to the supply roller, A pressure plate operating mechanism that can switch between an operating state in which the pressure plate is operated using the driving force of the motor and a non-operating state in which the pressure plate is not operated by cutting off the driving force of the motor, The system includes a switching mechanism that can switch the state of the pressure plate operating mechanism, The pressure plate operating mechanism is, The input gear to which the driving force is input, A sector gear having first tooth portions and second tooth portions that can mesh with the input gear, and first missing tooth portions and second missing tooth portions that do not mesh with the input gear, arranged on its outer surface in the order of first missing tooth portion, first tooth portion, second missing tooth portion, second tooth portion, and so on. A spring that biases the sector gear in the rotational direction of the sector gear, A movable gear that can move between a connected position that receives driving force from the sector gear and a disengaged position that does not receive driving force from the sector gear, A gear unit that operates the pressure plate by a driving force transmitted from the moving gear, An upstream gear that meshes with the moving gear located at the aforementioned connection position, The gear unit comprises a downstream gear that rotates together with the upstream gear when the upstream gear rotates by a first angle or more, The transmission switching mechanism is configured such that the state switches between a transmission state and a non-transmission state each time the sector gear rotates by a second angle. The aforementioned switching mechanism is A sector lever that can rotate between a rotation-restricting position that engages with the sector gear to stop the rotation of the sector gear due to the biasing force of the spring, and a rotation-allowing position that disengages from the sector gear to allow the rotation of the sector gear due to the biasing force of the spring, The sector lever is provided with a solenoid actuator for moving it between the rotation-restricting position and the rotation-allowing position, When the sector lever is in the rotation restricting position, the moving gear is in the disengaged position. When the sector lever is in the rotation-permissible position, the moving gear is in the coupling position. When the operating time of the solenoid actuator, which corresponds to the time for which the sector lever is maintained in the rotation-permissible position, is the first time, the downstream gear rotates, causing the pressure plate to move, and the sector gear rotates by the second angle, switching the state of the transmission switching mechanism between a transmission state and a non-transmission state. A sheet conveying device characterized in that, when the operating time of the solenoid actuator is a second time shorter than the first time, the position of the pressure plate is maintained by the downstream gear not rotating, and the state of the transmission switching mechanism is switched to a transmission state or a non-transmission state by the sector gear rotating by a second angle.

2. The aforementioned transmission switching mechanism is A planetary gear mechanism comprising a sun gear, planetary gears, planetary carriers, and internal gears, A transmission switching lever that can switch between a transmission position, in which the transmission switching mechanism is put into the transmission state by engaging with a first component, which is one of the three components of the sun gear, the planetary carrier, and the internal gear, and a non-transmission position, in which the transmission switching mechanism is put into the non-transmission state by disengaging from the first component, The sheet conveying device according to claim 1, further comprising a cam that rotates in conjunction with the sector gear, and which switches the transmission switching lever between the transmission position and the non-transmission position.

3. The pressure plate operating mechanism is, An interlocking gear that rotates together with the sector gear, comprising an interlocking gear capable of meshing with the moving gear located at the coupling position, The sheet conveying device according to claim 2, characterized in that the interlocking gear has the cam.

4. The aforementioned interlocking gear is, The sheet conveying device according to claim 3, characterized in that it has two toothed portions on its outer surface that can mesh with the moving gear located at the aforementioned connection position, and two toothless portions that do not mesh with the moving gear located at the aforementioned connection position.

5. The sheet conveying device according to claim 2, characterized in that the input gear is one of the three components of the planetary gear mechanism.

6. The sheet conveying device according to claim 1, characterized in that the gear unit includes a spring that biases the upstream gear toward its initial position.

7. The sheet conveying device according to claim 1, characterized in that the moving gear is rotatably supported on the sector lever.

8. A tray and A supply roller for transporting the sheet set in the tray, A pressure plate that moves between a contact position in which the sheet is in contact with the supply roller and a separation position in which the sheet is separated from the supply roller, Motor and, A transmission switching mechanism that can switch between a transmission state in which the driving force of the motor is transmitted to the supply roller and a non-transmission state in which the driving force of the motor is not transmitted to the supply roller, A pressure plate operating mechanism that can switch between an operating state in which the pressure plate is operated using the driving force of the motor and a non-operating state in which the pressure plate is not operated by cutting off the driving force of the motor, The system includes a solenoid actuator capable of switching the state of the pressure plate operating mechanism and the transmission switching mechanism, When the operating time of the solenoid actuator is the first hour, the state of the pressure plate operating mechanism is switched to the operating state and the pressure plate moves, and the state of the transmission switching mechanism is switched to the transmission state or the non-transmission state. A sheet conveying device characterized in that, when the operating time of the solenoid actuator is shorter than the first time (a second time), the state of the pressure plate operating mechanism is not switched to the operating state and the position of the pressure plate is maintained, and the state of the transmission switching mechanism is switched to either the transmission state or the non-transmission state.

9. The sheet transport device according to any one of claims 1 to 8, characterized in that the tray is a manual feed tray located on the side of the main housing of the image forming apparatus.

10. The sheet conveying device according to claim 9, The main casing and An image forming apparatus comprising a drawer from which multiple developing cartridges can be attached and detached, The main housing has an opening, The drawer is movable through the opening, The image forming apparatus is characterized in that the supply roller is located below the opening.

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