Paper feeding device and image forming device

Abstract

To provide a paper feeding device capable of easily correcting a deviation of a paper guide even when it is deviated because of a lifting operation of a paper placement plate.SOLUTION: A paper feeding device comprises: a recording medium placement plate capable of moving in a vertical direction containing a placement surface on which one or more recording media to be conveyed in a medium conveyance direction are placed; first and second recording medium guides which are provided at the recording medium placement plate to guide the recording medium placed on the placement surface in the medium conveyance direction and at which racks are formed; a first gear which is engaged with the respective racks for interlocking the first and second recording medium guides; a second gear provided with a ratchet tooth for forming a two-stage gear with the first gear; a regulation member having a tip part which is engaged with the ratchet tooth of the second gear for restricting an operation direction to one direction; a contact part interlocked with the regulation member; and a protrusion which is brought into contact with the contact part and urges the movement of the regulation member when the recording medium placement plate goes down or up.SELECTED DRAWING: Figure 8

Description

[Technical Field]

[0001] The present disclosure relates to a paper feeding device and an image forming apparatus. [Background technology]

[0002] 2. Description of the Related Art Conventionally, image forming apparatuses such as electrophotographic printers, facsimile machines, and copiers are provided with a medium cassette as a first medium loading section that can be attached to and detached from the image forming apparatus main body and that can load recording media such as paper.

[0003] For example, Patent Document 1 discloses a media cassette that includes a first gear that links a paper guide, a second gear that forms a two-stage gear together with the first gear, a second gear regulating member that regulates the rotation of the second gear, and a fixing means that fixes the second gear regulating member when the media cassette is inserted into the image forming device main body.

[0004] The image forming apparatus also includes a manual feed tray as a second medium loading section that is attached to the side of the apparatus body so as to be freely opened and closed, and that allows manual paper feeding.

[0005] For example, Patent Document 2 discloses a manual feed tray that includes a paper loading plate (paper loading plate) on which paper is loaded and which rises during printing, and a paper guide that regulates the widthwise position of the paper loaded on the paper loading plate to a predetermined position when the paper is fed into the image forming device main body when the paper loading plate rises. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2006-160391 [Patent Document 2] Japanese Patent Application Laid-Open No. 2013-133218 Summary of the Invention [Problem to be solved by the invention]

[0007] In the manual feed tray, the paper guide needs to be able to move freely when paper is set (when the paper tray is down), and it needs to be restricted only when the paper tray is up during printing.

[0008] However, with conventional manual feed trays, the paper guide could become misaligned when the paper loading plate was raised from its lowered position (in other words, when switching to printing), and the paper guide could become fixed in that misaligned position. To correct this misalignment, it was necessary to lower the paper loading plate again and move the paper guide, which was a problem that required extra work.

[0009] Therefore, there is a demand for a paper feeder and an image forming apparatus that can easily correct the misalignment of the paper guide when the paper loading plate is lifted. [Means for solving the problem]

[0010] The paper feeding device of the first disclosure is characterized by having a recording medium loading plate that can move up and down and includes a loading surface on which one or more recording media to be transported in a media transport direction are placed, first and second recording medium guides that are provided on the recording medium loading plate and guide the recording media placed on the loading surface in the media transport direction and each have a rack formed on them, a first gear that engages with each of the racks and moves the first and second recording medium guides together, a second gear that has ratchet teeth that form a two-stage gear together with the first gear, a regulating member that has a tip that engages with the ratchet teeth of the second gear to limit the direction of movement to one side, a contact portion that moves in conjunction with the regulating member, and a protrusion that comes into contact with the contact portion and promotes movement of the regulating member when the recording medium loading plate is lowered or raised.

[0011] The image forming apparatus of the second aspect of the present disclosure is characterized by having the paper feeding device of the first aspect of the present disclosure. [Effects of the Invention]

[0012] According to the present disclosure, even if the paper guide is misaligned due to the lifting operation of the paper loading plate, the misalignment can be easily corrected. [Brief explanation of the drawings]

[0013] [Figure 1] 1 is a schematic cross-sectional view of a printer equipped with a manual feed tray according to a first embodiment. [Figure 2] 1 is an external perspective view of a manual feed tray and its surrounding area according to a first embodiment, seen obliquely from above. [Figure 3] 1 is an external perspective view showing a state in which the manual feed tray according to the first embodiment is in an open state and the lever is further raised. FIG. [Figure 4] FIG. 2 is an external perspective view showing the configuration of a paper placement plate (front) according to the first embodiment. [Figure 5] FIG. 2 is an external perspective view showing the configuration of the paper placement plate (back) according to the first embodiment. [Figure 6] FIG. 3 is a partially enlarged view showing a state in which a part of the paper placing plate (rear side) according to the first embodiment is enlarged. [Figure 7] FIG. 1 is a cross-sectional view (part 1) of the manual feed tray according to the first embodiment, as viewed from the side (Y direction). [Figure 8] FIG. 10 is a cross-sectional view (part 2) of the manual feed tray according to the first embodiment when viewed from the side (Y direction). [Figure 9] FIG. 9 is an enlarged view showing a part of FIG. 8 in an enlarged state. [Figure 10] FIG. 10 is a cross-sectional view (part 1) of the manual feed tray according to the second embodiment, as viewed from the side (Y direction). [Figure 11] FIG. 10 is a cross-sectional view (part 2) of the manual feed tray according to the second embodiment, as viewed from the side (Y direction). [Figure 12] FIG. 12 is an enlarged view showing a part of FIG. 11 in an enlarged state. [Figure 13] FIG. 10 is a third cross-sectional view of the manual feed tray according to the second embodiment, as viewed from the side (Y direction). [Figure 14]FIG. 14 is an enlarged view showing a part of FIG. 13 in an enlarged state. [Figure 15] FIG. 10 is a fourth cross-sectional view of the manual feed tray according to the second embodiment, as viewed from the side (Y direction). [Figure 16] FIG. 10 is a cross-sectional view (part 1) of the manual feed tray according to the third embodiment, as viewed from the side (Y direction). [Figure 17] FIG. 11 is a cross-sectional view (part 2) of the manual feed tray according to the third embodiment, as viewed from the side (Y direction). [Figure 18] FIG. 18 is an enlarged view showing a part of FIG. 17 in an enlarged state. [Figure 19] FIG. 11 is a third cross-sectional view of the manual feed tray according to the third embodiment, as viewed from the side (Y direction). [Figure 20] FIG. 20 is an enlarged view showing a part of FIG. 19 in an enlarged state. [Figure 21] FIG. 10 is a cross-sectional view (part 1) of the manual feed tray according to the fourth embodiment, as viewed from the side (Y direction). [Figure 22] FIG. 13 is a cross-sectional view (part 2) of the manual feed tray according to the fourth embodiment, as viewed from the side (Y direction). [Figure 23] FIG. 13 is a cross-sectional view (part 3) of the manual feed tray according to the fourth embodiment, as viewed from the side (Y direction). DETAILED DESCRIPTION OF THE INVENTION

[0014] (A) First embodiment A first embodiment of an image forming apparatus according to the present disclosure will be described below in detail with reference to the drawings. The following describes an example in which a paper feeder and an image forming apparatus according to the present disclosure are applied to a printer.

[0015] (A-1) Configuration of the First Embodiment (A-1-1) Overall structure FIG. 1 is a schematic cross-sectional view of a printer equipped with a manual feed tray according to a first embodiment.

[0016] The printer 1 shown in FIG. 1 includes a paper tray 5, a paper feeding section 30, a manual feed tray 300 as a paper feed device, a paper transport section 40, an image forming section 10, and a fixing section 20.

[0017] The paper tray 5 is a tray in which recording paper P as a recording medium is stacked inside the printer 1, and a paper feeding section 30 that feeds out the recording paper P one sheet at a time is provided on the paper feeding side.

[0018] The paper feed section 30 is provided with a pickup roller 31 that is arranged to press against the topmost stack of recording paper P on the paper tray 5 when it rises to a predetermined height, and a feed roller 32 and a separation piece 34 that separate the paper fed by the pickup roller 31 into individual sheets.

[0019] The manual feed tray 300 is provided with a paper loading plate 302 on which recording paper P is placed, a pickup roller 303 arranged to be pressed against the paper loading plate 302, a feed roller 304 which separates the recording paper P fed out by the pickup roller 303 one sheet at a time, a holding member 110 (Figure 2(b)) which holds the pickup roller 303, and a retard roller 305.

[0020] The recording paper P on the paper loading plate 302 is fed to the feed roller 304 by the rotation of the pickup roller 303 driven by a motor (not shown), and is separated one sheet at a time by the feed roller 304 and the retard roller 305 and sent to the paper conveying section 40.

[0021] The paper transport unit 40 transports the recording paper P, which has been separated into individual sheets and fed out by the paper feed unit 30 or the manual feed tray 300, to the image forming unit 10. The paper transport unit 40 is provided with a pair of transport rollers 41, 42 for transporting the fed out recording paper P.

[0022] The image forming unit 10 has four toner image forming units 11 (11-K, 11-Y, 11-M, 11-C (hereinafter, when there is no need to distinguish between them, they will simply be referred to as toner image forming units 11)) arranged in series from the upstream side in the transport direction of the recording paper P, and a transfer unit 13 that transfers the toner images formed by each toner image forming unit 11 onto the top surface of the paper by coulomb force.

[0023] The toner image forming units 11 (11-K, 11-Y, 11-M, 11-C) develop a toner image (form an image) on a sheet of paper using toner (developer) of either black, yellow, magenta, or cyan. Each toner image forming unit 11 also has a photosensitive drum 12. In each toner image forming unit 11, the photosensitive drum 12 is charged by a charging roller (not shown), image data is written onto the rotating photosensitive drum 12 by an optical head (not shown), and the image data is developed with toner, thereby obtaining a toner image of the respective color on the photosensitive drum 12.

[0024] The transfer unit 13 has a transfer belt 14 that transports the recording paper P transported from the paper tray 50 or the manual feed tray 300 in the direction of the arrow, and four transfer rollers 15 that are arranged opposite the photosensitive drums 12 of each toner image forming unit 11 via the transfer belt 14. The transfer unit 13 transfers the toner images of each color formed on the photosensitive drums 12 of each toner image forming unit 11 onto the recording paper P in succession by Coulomb force.

[0025] The fixing unit 20 fixes the toner image transferred onto the recording paper P by the transfer unit 13 onto the paper using heat and pressure. The printer 1 is equipped with a pair of transport rollers 53 and a pair of discharge rollers 54 for transporting and discharging the recording paper P on which the toner image has been fixed. The printer 1 is also provided with a stacking unit 56 for stacking the discharged printed recording paper P.

[0026] In FIG. 1, the X-axis is the transport direction of the recording paper P as it passes through the image forming unit 10, the Y-axis is the direction of the rotation axis of the photosensitive drum 12, and the Z-axis is the direction perpendicular to these two axes. Furthermore, when the X-axis, Y-axis, and Z-axis are shown in other figures described later, these axes indicate the same direction. That is, the X-axis, Y-axis, and Z-axis in each figure indicate the arrangement direction when the depicted parts of each figure constitute the printer 1 shown in FIG. 1. Note that the printer 1 is arranged so that the Z-axis is approximately vertical.

[0027] (A-1-2) Manual Feed Tray 300 Details Fig. 2 is an external perspective view of the manual feed tray 300 and its surrounding area of the printer 1 according to the first embodiment, viewed obliquely from above. Fig. 2(a) shows a closed state in which the manual feed tray cover 301 is closed to store the manual feed tray 300, and Fig. 2(b) shows an open state in which the manual feed tray 300 is used and the manual feed tray cover 301 is open (a state in which an operator operates drawer sections 301g and 301h (see Fig. 2(a)) to release the lock and pull the manual feed tray cover 301 forward). Fig. 3 is an external perspective view showing the manual feed tray 300 in the open state, with the lever 315 further pulled up.

[0028] 2(b), manual feed tray cover 301 is rotatably provided on device frame 101, which serves as a frame member fixed to the printer 1 body as will be described later, and rotates between an open position in the open state and a closed position in the closed state. Paper placement plate 302 is rotatably provided on manual feed tray cover 301 as will be described later, and recording paper P as a recording medium is placed on top of it.

[0029] Holding member 110 is rotatably held by device frame 101, and the tips of a pair of arms 110a, 110b (only 110a is shown in FIG. 2) formed on both left and right sides slidably fit into guide grooves formed at corresponding positions on manual feed tray cover 301, limiting the range of rotation of manual feed tray cover 301. Lever 315 is also rotatably held by holding member 110, and as shown in FIG. 3, by rotating it, arm 315a of lever 315 fits into groove 302a of paper loading plate 302, allowing paper loading plate 302 to move up and down.

[0030] Fig. 4 is an external perspective view showing the configuration of the paper loading plate (front) according to the first embodiment. Fig. 5 is an external perspective view showing the configuration of the paper loading plate (back) according to the first embodiment. Fig. 6 is a diagram showing an enlarged view of a part of the paper loading plate (back) according to the first embodiment.

[0031] As shown in FIGS. 4 and 5, the paper placement plate 302 mainly includes paper guides 320 (320a, 320b), a pinion 322, and a lock lever 323.

[0032] Racks 321a and 321b, which may be integral or separate, are coupled to paper guides 320a and 320b, respectively. Pinion 322 (gear portion 322a) is provided midway between racks 321a and 321b. The pinion engages with racks 321a and 321b and moves paper guides 320a and 320b in the left-right direction together with racks 321a and 321b. Racks 321a and 321b are formed with teeth in the area that engages with gear portion 322a, which engage with teeth provided around the entire circumference of gear portion 322a. When one of paper guides 320 is moved, the other also moves in conjunction with it.

[0033] Ratchet portion 322b, which is molded separately from or integrally with gear portion 322a, is disposed coaxially with the rotation axis of gear portion 322a. Ratchet portion 322b is coupled to gear portion 322a and is configured to rotate simultaneously with gear portion 322a.

[0034] Ratchet portion 322b has a larger gear diameter than gear portion 322a, and has ratchet teeth formed along the entire circumference. The teeth of ratchet portion 322b engage with tip portion 323b of lock lever 323, which is molded integrally with paper cassette 21 or separately.

[0035] Lock lever 323 has tip portion 323b and contact portion 323a, and is rotatably attached to paper loading plate 302. Lock lever 323 is also pressed by spring 330 in a direction in which tip portion 323b engages with ratchet portion 322b of pinion 322.

[0036] The tip end portion 323b is configured to mesh with the teeth of the ratchet portion 322b of the pinion 322.

[0037] As shown in Figure 6, the ratchet portion 322b of the pinion 322 engages with the tip portion 323b of the lock lever 323, preventing the pinion 322 from rotating clockwise in the figure. On the other hand, the ratchet portion 322b pushes the lock lever 323 upward in the figure, allowing it to rotate counterclockwise in the figure. The pinion 322 rotates clockwise when the paper guides 320a and 320b move away from each other. The pinion 322 rotates counterclockwise when the paper guides 320a and 320b move toward each other.

[0038] Contact portion 323a is a portion that comes into contact with protrusion 324 (FIGS. 7 and 8) of manual tray cover 301 when paper loading plate 302 descends. When contact portion 323a comes into contact with protrusion 324, tip portion 323b moves in a direction away from ratchet portion 322b (in FIG. 6, the opposite direction to the pressing direction of spring 330).

[0039] 7 and 8 are cross-sectional views of manual tray 300 as viewed from the side (Y direction). Fig. 7 shows the state of manual tray 300 during printing (when paper loading plate 302 is raised), and Fig. 8 shows the state of manual tray 300 when paper is set (when paper loading plate 302 is lowered). Fig. 9 is a partially enlarged view showing a portion of Fig. 8 in an enlarged state.

[0040] 7 to 9, manual tray cover 301 has protrusion 324. Protrusion 324 is shaped to come into contact with contact portion 323a of lock lever 323 when paper loading plate 302 is lowered, moving lock lever 323 to the left in the figure. Furthermore, protrusion 324 is positioned so that it quickly moves away from lock lever 323 when paper loading plate 302 begins to rise from its lowered state.

[0041] (A-2) Operation of the First Embodiment Next, the operation of the manual feed tray 300 in the first embodiment will be described.

[0042] The operator operates drawers 301g and 301h (FIG. 2(a)) to open manual tray 300. In this state, as shown in FIG. 7, paper loading plate 302 is raised (the state when recording paper P is fed to paper transport section 40).

[0043] At this time, the lock lever 323 and the protrusion 324 are separated. That is, the tip 323b of the lock lever 323 is engaged with the ratchet portion 322b of the pinion 322. Therefore, the ratchet portion 322b of the pinion 322 cannot rotate clockwise, and the paper guide 320 (320a, 320b) cannot be widened (it can be narrowed).

[0044] Then, when the operator pulls up the lever 315, the recording paper P can be set on the top surface of the paper placement plate 302 (the paper guide 320 can be moved freely) (FIGS. 8 and 9).

[0045] As lever 315 is pulled up, paper placement plate 302 descends (moves toward manual tray cover 301). As paper placement plate 302 descends, contact portion 323a of lock lever 323 comes into contact with inclined portion 324a of protrusion 324 of manual tray cover 301, moves down the slope to a certain extent, and then stops in contact with inclined portion 324a. At the same time, tip portion 323b of lock lever 323 moves in a direction away from ratchet portion 322b of pinion 322 (in the direction of the arrow in the figure), and tip portion 323b and ratchet portion 322b are completely separated from each other.

[0046] (A-3) Effects of the First Embodiment As described above, the first embodiment provides the following advantages.

[0047] When paper loading plate 302 is raised in manual tray 300 (during printing), tip 323b of lock lever 323 is engaged with ratchet portion 322b of pinion 322, so paper guides 320a and 320b do not move away from each other. This prevents recording paper P from shifting during printing.

[0048] On the other hand, when paper loading plate 302 is lowered, tip 323b of lock lever 323 is separated from ratchet portion 322b of pinion 322, so paper guides 320a and 320b can move either away from each other or towards each other. As a result, when placing recording paper P on paper loading plate 302, paper guides 320a and 320b move freely and do not interfere with the work.

[0049] Furthermore, even when the paper loading plate 302 is rising, the shape (tooth shape) of the ratchet portion 322b and the tip portion 323b of the lock lever 323 allows the paper guides 320a, 320b to be moved in a direction that brings them closer to each other. Therefore, even if the paper guides 320a, 320b spread apart when the paper loading plate 302 is rising, the misalignment can be corrected by narrowing the paper guides 320a, 320b.

[0050] (B) Second embodiment A second embodiment of a paper feeder and an image forming apparatus according to the present disclosure will be described below in detail with reference to the drawings. In the following, an example in which the image forming apparatus according to the present disclosure is applied to a printer will be described.

[0051] (B-1) Configuration and operation of the second embodiment The basic configuration of printer 1 of the second embodiment is the same as the configuration of the first embodiment shown in Figures 1 to 3, so a description thereof will be omitted. However, manual feed tray 300 of the second embodiment differs in part in configuration and operation from manual feed tray 300 of the first embodiment, and the following description will focus on these differences.

[0052] Fig. 10 is a cross-sectional view of manual feed tray 300 according to the second embodiment as seen from the side (Y direction). Fig. 10 shows the state of manual feed tray 300 during printing (when paper loading plate 302 is raised).

[0053] 10, the contact portion 333a of the lock lever 333 of the second embodiment is convex, unlike the contact portion 323a of the first embodiment. The tip portion 333b that contacts the ratchet portion 322b is the same as the tip portion 323b described above.

[0054] Furthermore, protrusion 334 that comes into contact with contact portion 323a of lock lever 333 has a concave shape, which is different from that in the first embodiment. The respective concave and convex shapes are positioned so as to engage with each other when paper loading plate 302 is lowered.

[0055] When the operator pulls up lever 315 from the state shown in Figure 10, paper loading plate 302 descends to the state shown in Figures 11 and 12. Figure 11 shows the state in which paper loading plate 302 has descended, and Figure 12 shows an enlarged view of a portion of Figure 11.

[0056] At this time, the convex shape of contact portion 333a of lock lever 333 and the concave shape of protrusion 334 are engaged with each other at fitting portion 334a.

[0057] When the operator pushes paper loading plate 302 downward from the state shown in Figure 11 (or when lever 315 is further pulled up), paper loading plate 302 further descends to the state shown in Figures 13 and 14. Figure 13 shows the state in which paper loading plate 302 has descended further, and Figure 14 shows an enlarged view of a portion of Figure 13.

[0058] At this time, contact portion 333a of lock lever 333 comes into contact with inclined portion 334b from fitting portion 334a of protrusion 334, moves down the slope to a certain extent, and then stops in the state of contact with inclined portion 334b. At the same time, tip portion 333b of lock lever 333 moves in a direction away from ratchet portion 322b of pinion 322 (in the direction of the arrow in the figure), and tip portion 333b and ratchet portion 322b are completely separated from each other. In other words, this is the state when paper is set, where paper guide 320 can be not only narrowed but also widened.

[0059] 13, after setting paper, when the operator pulls down lever 315, contact portion 333a of lock lever 333, which had been in contact with inclined portion 334b and stopped, starts to climb up inclined portion 334b and moves away from fitting portion 334a (FIG. 15). When lever 315 is subsequently pulled down, the printer enters the state shown in FIG. 10 (printable state).

[0060] (B-2) Effects of the Second Embodiment As described above, the second embodiment provides the following advantages.

[0061] Even when the paper loading plate 302 is lowered (Figure 11), the tip 333b of the lock lever 333 is engaged with the ratchet portion 322b of the pinion 322, so the paper guides 320a and 320b do not move away from each other, preventing the user from unintentionally opening the paper guides.

[0062] Furthermore, by pushing paper loading plate 302 downward (or operating lever 315) (FIG. 13), tip 333b of lock lever 333 separates from ratchet portion 322b of pinion 322, allowing paper guides 320a, 320b to move either away from or towards each other. This allows paper guides 320a, 320b to move freely when placing recording paper P on paper loading plate 302, so work is not hindered.

[0063] Other effects of the second embodiment are similar to those of the first embodiment.

[0064] (C) Third embodiment A paper feeding device and an image forming apparatus according to a third embodiment of the present disclosure will be described in detail below with reference to the drawings. In the following, an example in which the image forming apparatus according to the present disclosure is applied to a printer will be described.

[0065] (C-1) Configuration and Operation of the Third Embodiment The basic configuration of printer 1 of the third embodiment is the same as the configuration of the first embodiment shown in Figures 1 to 3, so a description thereof will be omitted. However, manual feed tray 300 of the third embodiment differs in part in configuration and operation from manual feed tray 300 of the first embodiment, and the following description will focus on these differences.

[0066] Fig. 16 is a cross-sectional view of manual tray 300 according to the third embodiment as seen from the side (Y direction). Fig. 16 shows the state of manual tray 300 during printing (when paper loading plate 302 is raised).

[0067] 16, the lock lever 323 of the third embodiment is exactly the same as that of the first embodiment. However, the protrusion 344 that comes into contact with the contact portion 323a of the lock lever 323 is different from the protrusion 324 of the first embodiment. Specifically, the protrusion 344 is lower than the protrusion 324, and is positioned so that the protrusion 344 and the contact portion 323a of the lock lever 323 do not come into contact with each other when the paper loading plate 302 is lowered.

[0068] When the operator pulls up lever 315 from the state shown in Figure 16, paper loading plate 302 descends to the state shown in Figures 17 and 18. Figure 17 shows the state in which paper loading plate 302 has descended, and Figure 18 shows an enlarged view of a portion of Figure 17.

[0069] At this time, the contact portion 323a of the lock lever 323 is not in contact with the protrusion 344. In addition, the tip portion 323b of the lock lever 323 is engaged with the ratchet portion 322b of the pinion 322.

[0070] When the operator pushes paper loading plate 302 downward from the state shown in Figure 17 (or when lever 315 is further pulled up), paper loading plate 302 further descends to the state shown in Figures 19 and 20. Figure 19 shows the state in which paper loading plate 302 has descended further, and Figure 20 shows an enlarged view of a portion of Figure 19.

[0071] At this time, contact portion 323a of lock lever 323 comes into contact with inclined portion 344a of protrusion 344, moves down the slope to a certain extent, and then stops in the state of contact with inclined portion 344a. At the same time, tip portion 323b of lock lever 323 moves in a direction away from ratchet portion 322b of pinion 322 (in the direction of the arrow in the figure), and tip portion 323b and ratchet portion 322b are completely separated from each other. In other words, this is the state when paper is set, where paper guide 320 can be not only narrowed but also widened.

[0072] (C-2) Effects of the Third Embodiment As described above, the third embodiment provides the following advantages.

[0073] Even when the paper loading plate 302 is lowered (Figure 17), the tip 323b of the lock lever 323 is engaged with the ratchet portion 322b of the pinion 322, so the paper guides 320a and 320b do not move away from each other, preventing the user from unintentionally opening the paper guides.

[0074] Furthermore, by pushing the paper loading plate 302 downward (or operating the lever 315) (FIG. 19), the tip 323b of the lock lever 323 separates from the ratchet portion 322b of the pinion 322, allowing the paper guides 320a, 320b to move either away from or toward each other. This allows the paper guides 320a, 320b to move freely when placing the recording paper P on the paper loading plate 302, and does not impede the work. Furthermore, when the paper loading plate 302 is raised from its lowered state, the tip 323b of the lock lever 323 and the ratchet portion 322b of the pinion 322 remain engaged, preventing the paper guides 320a, 320b from spreading apart when the paper loading plate 302 is raised from its lowered state. This prevents the recording paper P from shifting between placement and printing.

[0075] Other effects of the third embodiment are similar to those of the first embodiment.

[0076] (D) Fourth embodiment A fourth embodiment of a paper feeder and an image forming apparatus according to the present disclosure will be described below in detail with reference to the drawings. In the following, an example in which the image forming apparatus according to the present disclosure is applied to a printer will be described.

[0077] (D-1) Configuration and Operation of the Fourth Embodiment The basic configuration of printer 1 of the fourth embodiment is the same as the configuration of the first embodiment shown in Figures 1 to 3, so a description thereof will be omitted. However, manual feed tray 300 of the fourth embodiment differs in part in configuration and operation from manual feed tray 300 of the first embodiment, and the following description will focus on these differences.

[0078] 21 is a cross-sectional view of manual tray 300 according to the third embodiment as seen from the side (Y direction). Fig. 21 shows the state of manual tray 300 during printing (when paper loading plate 302 is raised).

[0079] 21, the lock lever 323 of the third embodiment is exactly the same as that of the first (third) embodiment. However, the protrusion 354 that comes into contact with the contact portion 323a of the lock lever 323 is different from the protrusion 324 of the first embodiment.

[0080] Specifically, the protrusion 354 has the same height as the protrusion 324 of the first embodiment, but is structured to be able to slide left and right to change the position of the protrusion 354 within the manual feed tray cover 301. In this embodiment, an example is shown in which the protrusion 354 transitions between two states, one in which the protrusion 354 is moved to the left and one in which the protrusion 354 is moved to the right, by the operator's operation, but the transition states are not particularly limited. Furthermore, the slidable structure is not particularly limited, and a variety of methods can be applied.

[0081] <When protrusion 354 is moved to the left> 22 shows the state in which the paper loading plate 302 is lowered when the protrusion 354 in the manual feed tray cover 301 is set to the left. The operations of the lock lever 323, pinion 322, etc. at this time are the same as those in the first embodiment, and therefore will not be described.

[0082] <When protrusion 354 is moved to the right> 23 shows the state in which the paper loading plate 302 is lowered when the protrusion 354 in the manual feed tray cover 301 is set to the right. The operations of the lock lever 323, pinion 322, etc. at this time are the same as those in the third embodiment, and therefore will not be described here.

[0083] (D-2) Effects of the Fourth Embodiment As described above, the fourth embodiment provides the following effects.

[0084] When the paper loading plate 302 is in the lowered state, the operator can select whether the paper guides 320a and 320b are free to move away from each other (corresponding to the first embodiment), or whether they are prevented from moving and, if movement is desired, the paper loading plate 302 is lowered further (corresponding to the third embodiment) by sliding the protrusion 354.

[0085] Other effects of the fourth embodiment are similar to those of the first and second embodiments.

[0086] (E) Other embodiments The present disclosure is not limited to the above-described embodiment, and may include modified embodiments such as those exemplified below.

[0087] (E-1) In the above-described embodiment, an electrophotographic printer was used as an example of an image forming apparatus, but the present disclosure can also be applied to other devices such as a copier, a multifunction peripheral, and a fax machine.

[0088] (E-2) In the above-described embodiment, as shown in FIG. 6 etc., when tip portion 323b and ratchet portion 322b (and tip portion 333b and ratchet portion 322b) engage with each other, the middle of the teeth abuts so that there is no rattle even if the tip portion and ratchet portion are slightly worn down. However, if the durability of the tip portion and ratchet portion (pinion) can be maintained, the gap may be reduced so that the teeth abut near the base.

[0089] (E-3) In the third embodiment described above, the protrusion 344 is shorter in height than the protrusion 324 of the first embodiment, but the same effect can be obtained even if the contact portion 323a of the lock lever 323 is shortened. [Explanation of symbols]

[0090] 1...printer, 5...paper tray, 10...image forming section, 11...toner image forming section, 12...photosensitive drum, 13...transfer section, 14...transfer belt, 15...transfer roller, 20...fixing section, 21...paper cassette, 30...paper feeding section, 31...pickup roller, 32...feed roller, 34...separation piece, 40...paper transport section, 41...transport roller, 42...transport roller, 50...paper tray, 53...pair of transport rollers, 54...pair of discharge rollers, 56...accumulation section, 101...device frame, 110...holding member, 110a, 110b...arm, 300...manual feed tray, 301...manual feed tray cover, 301g, 301h...drawer section, 302...paper loading section Placement plate, 302a...groove, 303...pickup roller, 304...feed roller, 305...retard roller, 315...lever, 315a...arm, 320 (320a, 320b)...paper guide, 321 (321a, 321b)...pinion, 322...pinion, 322a...gear portion, 322b...ratchet portion, 323...lock lever, 323a...contact portion, 323b...tip portion, 324...protrusion, 324a...inclined portion, 330...spring, 333...lock lever, 333a...contact portion, 333b...tip portion, 334...protrusion, 334a...engagement portion, 334b...inclined portion, 344...protrusion, 344a...inclined portion, 354...protrusion, P...recording paper.

Claims

1. a recording medium placement plate that is movable up and down and includes a placement surface on which one or more recording media to be transported in a medium transport direction are placed; a first recording medium guide and a second recording medium guide, each of which has a rack, provided on the recording medium placement plate and which guide the recording medium placed on the placement surface in the medium transport direction; a first gear that engages with each of the racks and moves the first and second recording medium guides together; a second gear having ratchet teeth forming a two-stage gear with the first gear; a restricting member having a tip portion that engages with the ratchet teeth of the second gear to restrict the movement direction to one direction; a contact portion that interlocks with the regulating member; a protrusion that contacts the contact portion and prompts the movement of the regulating member when the recording medium placing plate is lowered or raised; A paper feeding device comprising:

2. 2. The paper feed device according to claim 1, wherein the protrusion contacts the contact portion when the recording medium loading plate is lowered, and maintains a shape that separates the tip of the regulating member from the ratchet teeth of the second gear.

3. The protrusion has a concave shape and the contact portion has a convex shape, When the recording medium placing plate is lowered, the concave shape of the protrusion and the convex shape of the contact portion are fitted together, and the engagement between the tip end of the regulating member and the ratchet teeth of the second gear is maintained. When the recording medium placing plate is further lowered, the concave shape of the protrusion and the convex shape of the contact portion are displaced from each other, and the tip of the regulating member is separated from the ratchet teeth of the second gear.

2. The paper feeder according to claim 1.

4. The protrusion is When the recording medium placing plate is lowered, it does not come into contact with the contact portion, When the recording medium placing plate is further lowered, it comes into contact with the contact portion, and maintains the shape that separates the tip end of the regulating member from the ratchet teeth of the second gear.

2. The paper feeder according to claim 1.

5. The protrusion holds a movable structure, and depending on the moving position, When the recording medium placing plate is lowered, it comes into contact with the contact portion, and separates the tip end of the regulating member from the ratchet teeth of the second gear; Alternatively, when the recording medium placing plate is lowered, it does not come into contact with the contact portion, and the engagement between the tip of the regulating member and the ratchet teeth of the second gear is maintained.

2. The paper feeder according to claim 1.

6. An image forming apparatus comprising the paper feeder according to any one of claims 1 to 5.

Images