Image forming apparatus

Abstract

The present invention provides an image forming apparatus that can suppress errors in feeding sheets. [Solution] The image forming apparatus comprises a sheet storage section for storing sheets, and a paper feed roller for transporting the uppermost sheet, which is the topmost sheet among the sheets stored in the sheet storage section, toward the main body of the image forming apparatus. When the downstream side in the sheet transport direction is considered the front and the upstream side is considered the rear, the sheet storage section has a rotating plate that rotates upward to tilt the mounting surface on which the sheets are placed, so that the front end of the topmost sheet comes into contact with the paper feed roller, a regulating plate that comes into contact with the rear end of the sheet and restricts the sheet's movement toward the rear, and a connecting section that engages and connects the rotating plate and the regulating plate so that the regulating plate moves toward the front in accordance with the upward rotation of the rotating plate. The connecting section is provided with a gap so that the rotating plate and the regulating plate do not engage until the inclination angle of the mounting surface reaches a predetermined angle.

Description

Technical Field

[0001] The present disclosure relates to an image forming apparatus.

Background Art

[0002] Patent Document 1 discloses a sheet feeding device. The sheet feeding device includes a sheet storage unit for storing sheets. In the sheet storage unit, a middle plate is provided that presses the sheets against the feed roller obliquely.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the sheet feeding device disclosed in Patent Document 1, the relationship between the inclination angle (rotation angle) of the middle plate and the distance by which the rear end regulating member pushes the rear end of the sheet to extrude the sheet from the upstream to the downstream in the conveyance direction is a proportional relationship. However, the relationship between the inclination angle of the middle plate and the sheet retreat distance by which the sheet retreats from the downstream to the upstream in the conveyance direction as the middle plate inclines is not necessarily a proportional relationship.

[0005] For this reason, in the sheet feeding device of Patent Document 1, when the distance by which the rear end regulating member extrudes the sheet is greater than the sheet retreat distance, the sheet may be extruded downstream in the conveyance direction more than necessary and may be sent out in a state of overlapping with the sheet that should be conveyed ahead of the sheet.

[0006] One aspect of the present disclosure has been made in view of this problem. One aspect of the present disclosure aims to provide, for example, an image forming apparatus capable of suppressing paper feeding errors of sheets.

Means for Solving the Problems

[0007] An image forming apparatus according to a first aspect of the present disclosure includes a sheet storage section for storing sheets, and a paper feed roller for transporting the uppermost sheet, which is the uppermost sheet among the sheets stored in the sheet storage section, toward the main body of the image forming apparatus. When the downstream side in the conveying direction of the sheet is considered the front and the upstream side is considered the rear, the sheet storage section includes a rotating plate that rotates upward to incline the mounting surface on which the sheets are placed, so as to bring the front end of the uppermost sheet into contact with the paper feed roller, a regulating plate that contacts the rear end of the sheet and restricts the sheet's movement toward the rear, and a connecting section that engages and connects the rotating plate and the regulating plate so as the rotating plate rotates upward, the regulating plate moves toward the front. The connecting section is provided with a gap such that the rotating plate and the regulating plate do not engage until the inclination angle of the mounting surface reaches a predetermined angle. [Brief explanation of the drawing]

[0008] [Figure 1] This is a schematic cross-sectional view showing an example of the internal structure of an image forming apparatus according to the present disclosure. [Figure 2] This is a perspective view of a paper feed cassette according to an embodiment of the present disclosure. [Figure 3] Figure 2 is a perspective view showing an example of the configuration of the rotating plate included in the paper feed cassette. [Figure 4] Figure 2 is a cross-sectional view of the paper feed cassette along line IV-IV. [Figure 5] Figure 2 is a perspective view showing an example of the configuration of the regulating plate included in the paper feed cassette. [Figure 6] This figure schematically shows the relationship between the position of the rotating plate when a full load of sheets is set on the mounting surface of the paper feed cassette according to the present disclosure, and the position of the rotating plate when a single sheet is set on the mounting surface. [Figure 7]This graph shows an example of the relationship between the distance the rear end of the rotating plate moves as the rotating plate rotates upward, and the distance the seat moves backward as the rotating plate rotates upward. [Figure 8] This figure schematically shows an example of the configuration of the connecting portion of the paper feed cassette according to the embodiment of this disclosure. [Figure 9] This figure schematically shows an example of the configuration of the connecting portion of the paper feed cassette according to the embodiment of this disclosure. [Figure 10] This figure schematically shows an example of the configuration of the connecting portion of the paper feed cassette according to the embodiment of this disclosure. [Modes for carrying out the invention]

[0009] The embodiments of this disclosure will be described below with reference to the drawings. In the drawings, the same or equivalent elements are denoted by the same reference numerals, and redundant descriptions are omitted.

[0010] (Image forming apparatus) The image forming apparatus 100 is a laser-type color printer that forms multi-color and monochrome images on a sheet on which an image is to be formed. The image forming apparatus 100 prints an image on the sheet based on image data read from a document by the image reading device 90 (described later) or image data received from an external source. In this embodiment, the image forming apparatus 100 is described using a laser-type color printer as an example, but it is not limited to this. For example, the image forming apparatus 100 may be an inkjet printer.

[0011] As shown in Figure 1, the image forming apparatus 100 comprises a printing unit 110, an image reading device 90, and an automatic document feeder 120. Figure 1 is a schematic cross-sectional view showing an example of the internal structure of the image forming apparatus 100 according to the embodiment of this disclosure. Note that the printing unit 110, the image reading device 90, and the automatic document feeder 120 may be collectively referred to as the main body of the image forming apparatus 100.

[0012] The printing unit 110 includes an exposure unit 1, a developing device 2, a photoreceptor drum 3, a cleaner unit 4, a charger 5, an intermediate transfer belt unit 6, a fixing unit 7, and a paper feed cassette 80 (sheet storage unit).

[0013] Above the printing unit 110, an image reading device 90 is provided with an original document placing table 92 made of transparent glass on its upper surface. Also, an automatic document feeder 120 is attached above the original document placing table 92.

[0014] The automatic document feeder 120 automatically conveys the original document onto the original document placing table 92. Also, the automatic document feeder 120 is configured to be able to rotate in the direction of arrow R. And by opening above the original document placing table 92, the original document can be placed on the original document placing table 92.

[0015] The image reading device 90 reads image data from the original document conveyed or placed on the original document placing table 92. The printing unit 110 prints an image on the sheet based on the image data read by the image reading device 90.

[0016] The image data handled in the image forming apparatus 100 corresponds to a color image using each color of yellow (Y), magenta (M), cyan (C), and black (K). Therefore, the developing device 2, the photoreceptor drum 3, the cleaner unit 4, and the charger 5 are respectively provided to form four types of latent images corresponding to each color.

[0017] The charger 5 uniformly charges the surface of the photoreceptor drum 3 to a predetermined potential. The charger 5 can use a charger of a charger type, a contact type, a brush type, or the like.

[0018] The exposure unit 1 is configured as a laser scanning unit (LSU) including a laser emission unit and a reflection mirror or the like. The exposure unit 1 includes a polygon mirror that scans a laser beam, and optical members such as a lens or a mirror for guiding the laser light reflected by the polygon mirror to the photoreceptor drum 3. The exposure unit 1 exposes the charged photoreceptor drum 3 according to image data, thereby forming an electrostatic latent image corresponding to the image data on its surface.

[0019] The developing unit 2 visualizes the electrostatic latent image formed on the photoreceptor drum 3 with toner. The developing unit 2 includes a developing tank 2a, and toner is stored in the developing tank 2a. The developing unit 2 is configured to supply the toner stored in the developing tank 2a to the photoreceptor drum 3. Each developing tank 2a is connected to each toner cartridge 20 that stores toner via a toner supply pipe (not shown). The toner cartridges 20 are provided corresponding to each of the four colors of toner.

[0020] The cleaner unit 4 removes and recovers the toner remaining on the surface of the photoreceptor drum 3 after development and image transfer.

[0021] An intermediate transfer belt unit 6 is disposed above the photoreceptor drum 3. The intermediate transfer belt unit 6 includes an intermediate transfer belt 61, an intermediate transfer belt driving roller 62, an intermediate transfer belt driven roller 63, a plurality of intermediate transfer rollers 64, and an intermediate transfer belt cleaning unit 65. Four intermediate transfer rollers 64 are provided corresponding to each of the colors Y, M, C, and K.

[0022] The intermediate transfer belt driving roller 62, the intermediate transfer belt driven roller 63, and the four intermediate transfer rollers 64 stretch and rotationally drive the intermediate transfer belt 61. Each intermediate transfer roller 64 applies a transfer bias for transferring the toner image on the photoreceptor drum 3 onto the intermediate transfer belt 61.

[0023] The intermediate transfer belt 61 is positioned to contact each photoreceptor drum 3. The toner images of each color formed on the photoreceptor drum 3 are then sequentially transferred onto the intermediate transfer belt 61, thereby forming a color toner image (multicolor toner image) on the intermediate transfer belt 61. The intermediate transfer belt 61 is formed in an endless manner using, for example, a film with a thickness of about 100 μm to 150 μm.

[0024] The transfer of the toner image from the photoreceptor drum 3 to the intermediate transfer belt 61 is performed by an intermediate transfer roller 64 that is in contact with the back side of the intermediate transfer belt 61. A high-voltage transfer bias (a high voltage with the opposite polarity (+) to the charge polarity (-) of the toner) is applied to the intermediate transfer roller 64 in order to transfer the toner image. The intermediate transfer roller 64 is a roller based on a metal (e.g., stainless steel) shaft with a diameter of 8 to 10 mm, and its surface is covered with a conductive elastic material (e.g., EPDM, foamed urethane, etc.). This conductive elastic material allows for the uniform application of a high voltage to the intermediate transfer belt 61.

[0025] The electrostatic latent images, manifested on each photoreceptor drum 3 according to their respective hues, are stacked on the intermediate transfer belt 61 and transferred onto the sheet by a transfer roller 10 positioned at the contact point between the sheet and the intermediate transfer belt 61.

[0026] At this time, the intermediate transfer belt 61 and the transfer roller 10 are pressed together at a predetermined nip, and a voltage is applied to the transfer roller 10 to transfer the toner to the sheet (a high voltage with the opposite polarity (+) to the charge polarity (-) of the toner).

[0027] Furthermore, as described above, toner that adheres to the intermediate transfer belt 61 by contacting the photoreceptor drum 3, or toner that remains on the intermediate transfer belt 61 because it was not transferred onto the sheet by the transfer roller 10, is removed and recovered by the intermediate transfer belt cleaning unit 65 because it can cause toner color mixing in the next process.

[0028] The intermediate transfer belt cleaning unit 65 includes, for example, a cleaning blade as a cleaning member that contacts the intermediate transfer belt 61. The surface of the intermediate transfer belt 61 opposite to the surface that contacts the cleaning blade is supported by the intermediate transfer belt driven roller 63.

[0029] The printing unit 110 is further equipped with a paper output tray 91. The paper output tray 91 collects the printed sheets face down.

[0030] The printing unit 110 is also provided with a sheet transport path S for sending sheets from the paper feed cassette 80 to the output tray 91 via the transfer roller 10 and the fuser unit 7. Along the sheet transport path S from the paper feed cassette 80 to the output tray 91, there are a paper feed roller 11a and a separation roller 11b, a pair of transport rollers 12a to 12d, a pair of registration rollers 13, a transfer roller 10, and the fuser unit 7, etc.

[0031] The paper feed roller 11a and the separation roller 11b are positioned so that their circumferential surfaces are in contact with each other. The sheets contained in the paper feed cassette 80 are stacked vertically. The top sheet of the stacked sheets (top sheet) is positioned so that its front end, which is downstream in the direction of sheet transport, is in contact with the paper feed roller 11a. The sheets are nipped between the paper feed roller 11a and the separation roller 11b and separated one by one. The separated sheets are then sandwiched between a pair of transport rollers 12a and transported to the register roller 13.

[0032] The pair of conveying rollers 12a and the pair of conveying rollers 12b to 12d described above are small rollers that assist in the conveying of sheets, and multiple units are provided along the sheet conveying path S.

[0033] The pair of register rollers 13 temporarily hold the sheet being transported in the sheet transport path S. The register rollers 13 transport the sheet to the transfer roller 10 at the timing when the leading edge of the toner image on the intermediate transfer belt 61 aligns with the leading edge of the sheet.

[0034] The fuser unit 7 is equipped with a heat roller 71 and a pressure roller 72, which rotate with the sheet between them. The heat roller 71 is set to a predetermined fixing temperature based on a signal from a temperature detector (not shown). The heat roller 71, together with the pressure roller 72, heat-presses the toner onto the sheet. In this way, the fuser unit 7 melts, mixes, and presses the multi-color toner image transferred to the sheet, and heat-fixes it to the sheet. The fuser unit 7 is also provided with an external heating belt 73 for heating the heat roller 71 from the outside.

[0035] In the image forming apparatus 100 having the above configuration, the printing unit 110 acquires image data and prints it onto a sheet as follows. Specifically, the printing unit 110 guides one or more sheets placed on the paper feed cassette 80 one by one into the sheet transport path S using the paper feed roller 11a and the separation roller 11b, and transports them to a pair of registration rollers 13 using a pair of transport rollers 12a. The pair of registration rollers 13 then transport the sheet to the transfer roller 10 at the timing when the leading edge of the sheet aligns with the leading edge of the toner image on the intermediate transfer belt 61, and the toner image is transferred onto the sheet. After that, the toner image is heat-fixed onto the sheet by passing the sheet through the fixing unit 7, and the sheet is discharged to the output tray 91 via the pair of transport rollers 12b.

[0036] (Paper feed cassette) The configuration of the paper feed cassette 80 provided in the image forming apparatus 100 according to the embodiment of this disclosure will be described with reference to Figures 2 to 5. For the sake of explanation, the downstream side in the sheet transport direction will be referred to as the front, and the upstream side as the rear. When viewing the paper feed cassette from above, the direction perpendicular to the transport direction will be referred to as the sheet width direction. Furthermore, when viewed from the rear towards the front, the left side in the sheet width direction will be referred to as the left, and the right side as the right.

[0037] Figure 2 is a perspective view of a paper feed cassette 80 according to an embodiment of the present disclosure. Figure 2 shows the configuration of the paper feed cassette 80 when viewed from above and downward. Figure 3 is a perspective view showing an example of the configuration of the rotating plate 30 included in the paper feed cassette 80 shown in Figure 2. Figure 4 is a cross-sectional view of the paper feed cassette 80 shown in Figure 2, taken along line IV-IV. Figure 5 is a perspective view showing an example of the configuration of the regulating plate 40 included in the paper feed cassette 80 shown in Figure 2.

[0038] As shown in Figure 2, the paper feed cassette 80 includes a rectangular bottom 81, and a first side wall 82, a second side wall 83, a third side wall 84, and a fourth side wall 85 that are erected upward from the bottom 81 along the outer circumference of the bottom 81.

[0039] The first side wall 82 is connected to the front edge of the bottom 81, the second side wall 83 to the rear edge of the bottom 81, the third side wall 84 to the left edge of the bottom 81, and the fourth side wall 85 to the right edge of the bottom 81. The paper feed cassette 80 is formed by the bottom 81, the first side wall 82, the second side wall 83, the third side wall 84, and the fourth side wall 85, creating a rectangular parallelepiped container with an open top.

[0040] One or more sheets are placed in predetermined positions within the sheet-receiving area enclosed by the bottom 81, the first side wall 82, the second side wall 83, the third side wall 84, and the fourth side wall 85. For the sake of clarity, the sheets are not shown in Figure 2.

[0041] The first side wall 82 on the front side of the paper feed cassette 80 is provided with a pair of roller support parts 87 that support the separation roller 11b. The roller support parts 87 rotatably support the roller rotation shaft 14 that rotates the separation roller 11b.

[0042] A rotating plate 30 is provided in front of the bottom portion 81, and a restricting plate 40 is provided behind the bottom portion 81. The rotating plate 30 is a rectangular plate-shaped member provided so as to cover the upper surface in front of the bottom portion 81. On the other hand, the restricting plate 40 is a plate-shaped member provided so as to extend along the transport direction (front-to-back direction) behind the bottom portion 81.

[0043] The rotating plate 30 includes a mounting section 31, a first rotating plate side wall 32, and a second rotating plate side wall 33, as shown in Figures 2 and 3.

[0044] As shown in Figure 4, the mounting portion 31 is a flat plate-shaped member that extends along the main surface of the bottom portion 81 on the bottom portion 81 and has a mounting surface 31a on which the sheet is placed. The first rotating plate side wall 32 is connected to the left edge of the mounting portion 31 and is erected upward from the mounting portion 31 along the third side wall 84. The second rotating plate side wall 33 is connected to the right edge of the mounting portion 31 and is erected upward from the mounting portion 31 along the fourth side wall 85.

[0045] A rotating shaft 34 is provided at the rear upper corner of the first rotating plate side wall 32, projecting toward the third side wall 84 and rotatably connected to the third side wall 84. Similarly, a rotating shaft 34 is provided at the rear upper corner of the second rotating plate side wall 33, projecting toward the fourth side wall 85 and rotatably connected to the fourth side wall 85.

[0046] In other words, the rotation axes 34 provided on the first rotating plate side wall 32 and the second rotating plate side wall 33 intersect perpendicularly with the transport direction (front-to-back direction) when the paper feed cassette 80 is viewed from above, and lie on the same virtual axis of rotation that extends along the main surface of the bottom 81. The rotating plate 30 is attached to the paper feed cassette 80 so as to be able to rotate freely in the vertical direction within a defined angular range with these rotation axes 34 as the center of rotation.

[0047] Furthermore, as shown in Figure 3, a pair of engaging portions 51 are provided at the center of the rear edge of the rotating plate 30, where it is in contact with the front edge of the regulating plate 40. The pair of engaging portions 51 protrude rearward from the rear edge of the rotating plate and engage with the engaging shaft 52 of the regulating plate 40, which will be described later.

[0048] Here, when a full load of sheets is set in the sheet storage area of ​​the paper feed cassette 80, the mounting surface 31a of the rotating plate 30 is in a horizontal position along the bottom 81. As shown in Figure 4, an elastic member 86 is provided between the lower surface of the mounting portion 31 and the upper surface of the bottom 81, which applies a biasing force to the rotating plate 30 from the bottom 81 upwards. Examples of the elastic member 86 include a compression coil spring and a leaf spring.

[0049] As the number of sheets placed on the mounting surface 31a decreases and the mass of the sheets on the mounting surface 31a decreases, the rotating plate 30 rotates upward around the rotation axis 34 due to the biasing force of the elastic member 86. As a result, the front end of the mounting portion 31 moves upward and the mounting surface 31a becomes inclined with respect to the horizontal plane.

[0050] Furthermore, the rotating plate 30 is provided with a pair of first guides 35 that are movable in the width direction of the sheet. Each of the pair of first guides 35 is erected on the rotating plate 30, extending upward from the mounting portion 31. One of the pair of first guides 35 moves along the width direction of the sheet from the left side of the mounting portion 31 to the right. The other first guide 35 moves along the width direction of the sheet from the right side of the mounting portion 31 to the left. Because the pair of first guides can move along the width direction of the sheet in this way, the sheet can be positioned at any position in the sheet width direction. In other words, the sheet can be positioned in the width direction by gripping it with each of the pair of first guides 35.

[0051] The front edge of the regulating plate 40 is connected to the rear edge of the rotating plate 30 via a connecting portion 50 (see Figure 8, described later). The regulating plate 40 is provided at the bottom 81 so that it can move along the transport direction (front-to-back direction) in accordance with the rotation of the rotating plate 30.

[0052] In other words, the regulating plate 40 moves downstream (forward) in the conveying direction in accordance with the upward rotation of the rotating plate 30. Also, the regulating plate 40 moves upstream (rearward) in the conveying direction in accordance with the downward rotation of the rotating plate 30. The detailed configuration of the connecting section 50 will be described later.

[0053] As shown in Figure 5, the regulating plate 40 has a regulating plate body 41, a second guide 42 (contact surface), and a pair of slider parts 43.

[0054] The regulating plate body 41 is a plate-shaped member that extends in the transport direction (front-to-back direction). The regulating plate body 41 is movable along the transport direction (front-to-back direction) at the bottom 81 of the paper feed cassette 80.

[0055] Specifically, the left and right sides of the regulating plate body 41 are provided with flat, plate-shaped slider portions 43 that protrude outward in the left-right direction and extend in the transport direction (front-back direction). On the other hand, the bottom portion 81 of the paper feed cassette 80 has an opening into which the regulating plate 40 can be fitted. Rail portions (not shown) that engage with the slider portions 43 are provided at the left and right edges of the opening so that the slider portions 43 can slide. As the slider portions 43 slide along the rail portions, the regulating plate 40 becomes movable in the transport direction (front-back direction) within the paper feed cassette 80.

[0056] Furthermore, the front edge of the regulating plate body 41 is provided with an engagement shaft 52 that engages with the engagement portion 51 of the rotating plate 30. In other words, the front end of the regulating plate body 41 is provided with a recess that is recessed toward the rear. The engagement shaft 52 is provided in this recess so as to extend in the left-right direction.

[0057] The second guide 42 is erected above the regulating plate body 41 and contacts the rear end of the sheet placed on the mounting surface 31a of the rotating plate 30. The second guide 42 is configured to move along the transport direction (front-to-back direction) from the rear end to the front end of the regulating plate body 41 and to be fixed in any position.

[0058] Therefore, the second guide 42 moves along the transport direction (front-to-back direction) from the rear end to the front end of the regulating plate body 41. When the second guide 42 is fixed in a position where it contacts the rear end of the sheet, the sheet can be positioned in the transport direction (front-to-back direction).

[0059] Furthermore, as the rotating plate 30 rotates upward and the mounting surface 31a tilts, the sheet retracts to the rear side of the mounting surface 31a, i.e., to the upstream side in the transport direction. However, the paper feed cassette 80 is equipped with a regulating plate 40 having a second guide 42, which prevents the sheet from retracting to the upstream side in the transport direction.

[0060] Furthermore, as the inclination angle of the mounting surface 31a increases, the distance the sheet moves backward (sheet retreat distance) increases. On the other hand, as the inclination angle of the mounting surface 31a increases, the distance the regulating plate body 41 moves downstream in the transport direction (front-back direction) increases.

[0061] Due to this relationship between the sheet retraction distance and the movement distance of the regulating plate body 41, the regulating plate body 41 can push the retracting sheet downstream in the transport direction (forward and backward direction).

[0062] (Distance traveled from the rear end of the rotating plate and distance traveled back of the seat) Here, the relationship between the rotational plate rear end position movement distance and the sheet retraction distance will be explained with reference to Figures 6 and 7. Figure 6 is a schematic diagram showing the relationship between the position of the rotational plate 30 when a full load of sheets is set on the mounting surface 31a and the position of the rotational plate 30 when one sheet is set on the mounting surface 31a in the paper feed cassette 80 according to the present disclosure. Figure 7 is a graph showing an example of the relationship between the rotational plate rear end position movement distance, which is the distance the rear end position of the rotational plate 30 moves as the rotational plate 30 rotates upward, and the sheet retraction distance, which is the distance the sheet retracts backward as the rotational plate rotates upward.

[0063] As shown in Figure 6, when the rotating plate 30 rotates upward around the rotation axis 34, the rear end of the rotating plate moves downstream in the conveying direction, i.e., forward. Furthermore, as the rotating plate 30 rotates upward, the regulating plate 40 connected to it also moves forward. Therefore, the distance the rear end of the rotating plate moves can be considered as the distance the regulating plate 40 pushes the sheet forward (the distance the regulating plate body 41 moves).

[0064] Furthermore, as the rotating plate 30 rotates upward, the mounting surface 31a tilts, causing the sheet placed on the mounting surface 31a to move backward.

[0065] Here, L1 is the horizontal distance from the center of the rotation axis 34 to the front end of the rotating plate 30, and L2 is the distance from the center of the rotation axis 34 to the rear end of the rotating plate 30. Also, θ is the inclination angle of the mounting surface 31a that allows the front end of a sheet to contact the paper feed roller 11a when one sheet is set on the mounting surface 31a.

[0066] At this time, when the mounting surface 31a goes from a fully loaded state to a single sheet, the sheet retraction distance of the front end of the sheet is approximately L1 - L1cosθ. On the other hand, the distance the rear end of the rotating plate moves is approximately L2·sinθ.

[0067] The relationship between the sheet retraction distance and the rotational plate rear end position movement distance is shown in the graph in Figure 7. Graph (i) in Figure 7 shows the relationship between the inclination angle (angle (°)) of the mounting surface 31a and the rotational plate rear end position movement distance (distance (mm)) when no gap G is provided in the connecting portion 50. Graph (ii) shows the relationship between the inclination angle (angle (°)) of the mounting surface 31a and the sheet retraction distance (distance (mm)). Graph (iii) shows the relationship between the inclination angle (angle (°)) of the mounting surface 31a and the rotational plate rear end position movement distance (distance (mm)) when a gap G is provided in the connecting portion 50. Note that gap G refers to the gap provided between the engaging portion 51 and the engaging shaft 52, which will be described later, in the connecting portion 50.

[0068] As shown in graph (i) of Figure 7, the distance the rear end of the rotating plate moves increases proportionally as the inclination angle of the mounting surface 31a increases.

[0069] On the other hand, as shown in graph (ii) of Figure 7, the sheet retraction distance hardly increases until the inclination angle reaches about 3 degrees, and then gradually increases exponentially as the inclination angle increases. In other words, during the period until the inclination angle of the mounting surface 31a reaches a predetermined angle (for example, 3 degrees), the distance the sheet moves upstream in the conveying direction, i.e., the sheet retraction distance, is small due to the influence of static friction force acting between the mounting surface 31a and the sheet.

[0070] Therefore, if the regulating plate 40 is moved downstream in the conveying direction, i.e., forward, from the moment the rotating plate 30 starts rotating, the sheets may be pushed towards the paper feed roller 11a more than necessary, potentially causing multiple sheets to be fed at once by the paper feed roller 11a.

[0071] Therefore, in the paper feed cassette 80, a gap G is provided in the connecting section 50 that connects the rotating plate 30 and the regulating plate 40, and the rotating plate 30 and the regulating plate 40 are not connected until the inclination angle of the mounting surface 31a reaches a predetermined angle. More specifically, the connecting section 50 is configured as follows.

[0072] (Connection part) Next, the configuration of the connecting portion 50 provided in the paper feed cassette 80 will be described with reference to Figure 8. Figure 8 is a schematic diagram showing an example of the configuration of the connecting portion 50 provided in the paper feed cassette 80 according to the embodiment of this disclosure. Figure 8(a) shows the configuration of the connecting portion 50 when the mounting surface 31a is in a horizontal position, Figure 8(b) shows the configuration of the connecting portion 50 when the inclination angle of the mounting surface 31a is a predetermined angle (for example, 6 degrees), and Figure 8(c) shows the configuration of the connecting portion 50 when the inclination angle of the mounting surface 31a is greater than the predetermined angle (for example, 6 degrees).

[0073] As shown in Figure 8, the connecting portion 50 includes an engaging shaft 52 and an engaging portion 51. The engaging shaft 52 is a shaft provided on the regulating plate 40. As described above, the engaging shaft 52 extends along the width direction (left-right direction) of the sheet on the regulating plate 40.

[0074] The engaging portion 51 is a member that contacts and engages with the engaging shaft 52. In Figure 8, for the sake of explanation, only the engaging portion 51 provided on the right side of the rotating plate 30 is shown.

[0075] The engaging portion 51 protrudes rearward from the rear end of the rotating plate 30 and has a curved portion 51a that is curved so as to be convex towards the rear. The inner circumference of the curved portion 51a abuts against the engaging shaft 52 and engages so as to be rotatable around the engaging shaft 52.

[0076] In the connecting portion 50, a gap G is provided between the engaging shaft 52 and the engaging portion 51 so that the engaging shaft 52 and the engaging portion 51 do not come into contact until the rotating plate 30 rotates upward and the inclination angle of the mounting surface 31a reaches a predetermined angle.

[0077] In other words, as shown in Figure 8(a), when the mounting surface 31a of the rotating plate 30 is in a horizontal position, a predetermined gap G is provided between the engaging shaft 52 and the curved portion 51a of the engaging portion 51 behind the engaging shaft 52. Also, the rear contact surface 30a of the rotating plate 30 and the front contact surface 40a of the regulating plate 40 are in contact.

[0078] Then, as shown in Figure 8(b), when the inclination angle of the mounting surface 31a reaches a predetermined angle (for example, 6 degrees), the curved portion 51a of the engaging portion 51 contacts and engages with the engaging shaft 52, exerting a force to pull the regulating plate 40 downstream in the conveying direction, i.e., forward. At this time, the rear contact surface 30a of the rotating plate 30 and the front contact surface 40a of the regulating plate 40 are separated by the distance of the gap G.

[0079] As shown in Figure 8(c), as the inclination angle of the mounting surface increases beyond a predetermined angle, the regulating plate is pulled forward and moved.

[0080] In this configuration, when a gap G is provided between the engaging portion 51 and the engaging shaft 52 in the connecting portion 50, the relationship between the inclination angle of the mounting surface 31a and the distance the rear end of the rotating plate moves is shown in graph (iii) of Figure 7. As shown in graphs (ii) and (iii) of Figure 7, in the paper feed cassette 80 according to the embodiment of this disclosure, the sheet retraction distance and the distance the rear end of the rotating plate moves coincide when the inclination angle of the mounting surface 31a is 12 degrees. Note that an inclination angle of 12 degrees for the mounting surface 31a is the angle at which the front end of the uppermost sheet can be brought into contact with the paper feed roller 11a when one sheet is set on the mounting surface 31a.

[0081] Furthermore, in order for the engaging shaft 52 and the engaging portion 51 to come into contact when the inclination angle of the mounting surface 31a is 6 degrees, a gap G of 3.5 mm is provided between the engaging portion 51 and the engaging shaft 52, as shown in graphs (i) and (iii) of Figure 7.

[0082] The distance of the gap G between the engaging shaft 52 and the engaging portion 51 can be set such that the distance the rear end of the rotating plate moves and the distance the sheet retracts coincide when the inclination angle (12 degrees) allows the front end of a single sheet set on the mounting surface 31a to contact the paper feed roller 11a, as described above.

[0083] Furthermore, when the rotating plate 30 rotates downward from a tilted position on the mounting surface 31a back to a horizontal position, the rear contact surface 30a of the rotating plate 30 comes into contact with the front contact surface 40a of the regulating plate 40, pushing the regulating plate 40 upstream in the transport direction, i.e., backward. The regulating plate 40, pushed backward by the rotating plate 30, returns to its initial position.

[0084] Then, as shown in Figure 8(a), the front contact surface 40a of the regulating plate 40 and the rear contact surface 30a of the rotating plate 30 come into contact, and the curved portion 51a of the engaging portion 51 moves away from the engaging shaft 52 by a predetermined distance (play G).

[0085] As described above, the paper feed cassette 80 according to this disclosure has a gap G between the engaging portion 51 and the engaging shaft 52 in the connecting portion 50. Therefore, the regulating plate 40 does not engage with the rotating plate 30 during the period from when the rotating plate 30 starts to rotate until the inclination angle of the mounting surface 31a reaches a predetermined angle. Consequently, the regulating plate 40 does not move forward during the period from when the rotating plate 30 starts to rotate until the inclination angle of the mounting surface 31a reaches a predetermined angle.

[0086] Here, during the period from the horizontal position to a predetermined angle of inclination of the mounting surface 31a, the distance the sheet retracts becomes smaller due to the influence of static friction force and other factors acting between the mounting surface 31a and the sheet. Therefore, in a configuration where the regulating plate 40 is moved forward according to the inclination angle of the mounting surface 31a from the start of rotation of the rotating plate 30, the regulating plate 40 pushes the top sheet towards the paper feed roller 11a beyond the sheet retraction distance. When the top sheet is pushed towards the paper feed roller 11a beyond the sheet retraction distance in this way, there is a possibility that multiple sheets, including the top sheet, will be fed together by the paper feed roller 11a.

[0087] In the image forming apparatus 100 according to this disclosure, a gap G is provided between the engaging portion 51 and the engaging shaft 52 in the connecting portion 50. Therefore, the rotating plate 30 and the regulating plate 40 do not engage until the inclination angle of the mounting surface 31a reaches a predetermined angle, and the regulating plate 40 does not move backward. This prevents multiple sheets, including the top sheet, from being stacked by the paper feed roller 11a.

[0088] The engaging portion 51 constituting the connecting portion 50 according to the embodiment of this disclosure is not limited to the configuration having the curved portion 51a described above. As shown in Figure 9, the engaging portion 51 may have an annular portion 51b provided so as to protrude toward the rear from the rear end of the rotating plate 30. Figure 9 is a schematic diagram showing an example of the configuration of the connecting portion 50 provided in the paper feed cassette 80 according to the embodiment of this disclosure. Figure 9 shows the configuration of the connecting portion 50 when the mounting surface 31a is in a horizontal position. In Figure 9, for the sake of explanation, only the engaging portion 51 provided on the right side of the rotating plate 30 is shown, but a similar engaging portion 51 is also provided on the left side of the rotating plate 30.

[0089] An engaging shaft 52 is inserted through the annular portion 51b of the engaging portion 51. The engaging portion 51 abuts against the engaging shaft 52 on the inner circumference side of the annular portion 51b and engages so as to be rotatable around the engaging shaft 52. When the mounting surface 31a is in a horizontal position, a gap G is provided between the engaging shaft 52 and the contact position on the inner circumference side of the annular portion 51b where the engaging shaft 52 abuts.

[0090] Furthermore, as shown in Figure 10, the engaging portion 51 may be configured to protrude backward from the rear end of the rotating plate 30 and to have a bent portion 51c that bends downward in a direction intersecting the regulating plate 40. Figure 10 is a schematic diagram showing an example of the configuration of the connecting portion 50 provided in the paper feed cassette 80 according to the embodiment of this disclosure. Figure 10 shows the configuration of the connecting portion 50 when the mounting surface 31a is in a horizontal position. In Figure 10, for the sake of explanation, only the engaging portion 51 provided on the right side of the rotating plate 30 is shown, but a similar engaging portion 51 is also provided on the left side of the rotating plate 30.

[0091] The engaging portion 51 contacts the engaging shaft 52 on the front surface of the bent portion 51c and engages so as to be rotatable around the engaging shaft 52. When the mounting surface 31a is in a horizontal position, a gap G is provided between the engaging shaft 52 and the front surface of the bent portion 51c. [Explanation of symbols]

[0092] 11a Paper feed roller 11b Separation roller 14 Roller rotation axis 30 Rotating Plates 30a Rear contact surface 31 Mounting section 31a Mounting surface 32. Side wall of the first rotating plate 33. Side wall of the second rotating plate 34 Rotation axis 35 Guide 1 40 Restriction board 40a Front contact surface 41 Regulatory board body 42 Guide 2 50 Connecting part 51 Engaging part 51a Curved section 51b Ring section 51c Bend part 52 Engagement axis 80 Paper feed cassette 81 Bottom 82 First side wall 83 Second side wall 84 Third side wall 85. Fourth side wall 86 Elastic members 87 Roller support section 100 Image forming apparatus 110 Printing Department

Claims

1. A seat storage compartment for storing the seat, The image forming apparatus comprises a paper feed roller that transports the uppermost sheet, which is the uppermost sheet among the sheets stored in the sheet storage section, toward the main body of the image forming apparatus, When the downstream side in the conveying direction of the sheet is considered the front and the upstream side is considered the rear, The aforementioned seat storage section is A rotating plate that rotates upward to tilt the mounting surface on which the sheet is placed, so that the front edge of the uppermost sheet comes into contact with the paper feed roller, A restricting plate that abuts against the rear end of the sheet and restricts the sheet's movement backward, A connecting portion engages and connects the rotating plate and the regulating plate so as the rotating plate rotates upward, the regulating plate moves forward. It has, The connecting portion is provided with a gap such that the rotating plate and the regulating plate do not engage until the inclination angle of the mounting surface described above reaches a predetermined angle, in an image forming apparatus.

2. The aforementioned regulatory plate is, A regulating plate body that is movable along the aforementioned transport direction, The image forming apparatus according to claim 1, further comprising: a contact surface erected above the regulating plate body and in contact with the rear end of the sheet placed on the aforementioned mounting surface.

3. The aforementioned connecting portion is An engaging shaft is provided at the front end of the regulating plate and extends along the width direction of the sheet, The rotating plate includes an engaging portion that is provided so as to protrude toward the rear from its rear end and abuts against and engages with the engaging shaft, When the aforementioned mounting surface of the rotating plate is in a horizontal position, the clearance is provided between the engagement shaft and the engagement portion at the rear of the engagement shaft. The image forming apparatus according to claim 1 or 2, wherein when the inclination angle of the mounting surface becomes greater than or equal to a predetermined angle, the engaging portion contacts and engages with the engaging shaft, and exerts a force to pull the regulating plate downstream in the conveying direction.

4. The aforementioned engaging portion is It has a curved section that curves so as to become convex towards the rear, The image forming apparatus according to claim 3, wherein the inner circumference of the curved portion abuts against the engaging shaft and engages with it so as to be rotatable about the axis of the engaging shaft.

5. The aforementioned engaging portion is It has an annular portion through which the engagement shaft is inserted, The image forming apparatus according to claim 3, wherein the inner circumference of the annular portion abuts against the engaging shaft and engages with it so as to be rotatable about the axis of the engaging shaft.

6. The aforementioned engaging portion is It has a bent portion that bends downward in a direction intersecting with the regulating plate, The image forming apparatus according to claim 3, wherein the front surface of the bent portion abuts against the engaging shaft and engages with the engaging shaft so as to be rotatable around the axis of the engaging shaft.

7. The image forming apparatus according to claim 1, further comprising a biasing member that rotates the rotating plate upward in accordance with the decrease in the number of sheets placed on the mounting surface.

Images