Roller unit, and image forming device

Abstract

To facilitate an operation of attaching / detaching a roller unit to / from an image forming device.SOLUTION: According to a roller unit 60 that is attachable / detachable to / from an image forming device 100, the roller unit comprising a conveyance roller 61 for conveying a sheet S, that is opposed to or is brought into contact with a separation roller 113 provided in the image forming device 100 is made to be attachable to the image forming device 100 toward an upstream side in a conveyance direction F of the sheet S conveyed by the separation roller 113 and the conveyance roller 61 while eliminating the need of a movement operation along a center line direction of the conveyance roller 61.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a roller unit and an image forming apparatus. [Background technology]

[0002] Image forming apparatuses are equipped with transport rollers that transport sheets from a predetermined supply point. These transport rollers are subject to wear and deterioration with use, resulting in a decrease in performance. For this reason, the transport rollers are made into a detachable unit from the image forming apparatus, making replacement easier (see, for example, Patent Documents 1 and 2). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2017-030914 [Patent Document 2] Japanese Patent Application Laid-Open No. 2017-065865 Summary of the Invention [Problem to be solved by the invention]

[0004] When attaching or detaching the roller unit to or from the image forming apparatus, the roller unit requires two operations: movement in the insertion / removal direction and movement in the direction of the roller axis. This makes the attachment / detachment process for the image forming apparatus complicated.

[0005] SUMMARY OF THE INVENTION An object of the present invention is to facilitate the attachment and detachment of a roller unit to and from an image forming apparatus. [Means for solving the problem]

[0006] In order to solve the above problems, the roller unit of the present invention comprises: A roller unit detachable from an image forming apparatus, the roller unit comprising a conveying roller that faces or contacts a separation roller provided in the image forming apparatus to convey a sheet, The sheet conveying device is configured so as to be mountable on the image forming apparatus toward the upstream side in the conveying direction of the sheet by the separation roller and the conveying roller.

[0007] In order to solve the above problem, the image forming apparatus of the present invention is configured to include the roller unit described above.

[0008] Another image forming apparatus includes: a roller unit having an input unit that receives an input of a driving force that rotates a transport roller; a first power transmission body that directly inputs a driving force to the input portion from outside the roller unit, When viewed from the center line direction of the input portion, the mounting direction of the roller unit and the line segment connecting the center of the input portion and the center of the first power transmission body are configured to be perpendicular to each other.

[0009] In another image forming apparatus, an input unit for receiving an input of a driving force for rotating a transport roller is a roller unit, a second power transmission body that directly or indirectly inputs a driving force to the input portion from outside the roller unit; an openable door having a mounting portion for the roller unit; With the door open, the roller unit can be attached to the attachment section, When the door is open, the input of driving force from the second power transmission body to the input portion is cut off. [Effects of the Invention]

[0010] According to the present invention, it is possible to facilitate the attachment and detachment of a roller unit to and from an image forming apparatus. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is a diagram illustrating a schematic configuration of an image forming apparatus according to an embodiment of the present invention. [Figure 2]FIG. 2 is a perspective view showing the image forming apparatus with the door open. [Figure 3] FIG. 2 is a cross-sectional view showing the roller unit attached to the door and the surrounding structure. [Figure 4] FIG. [Figure 5] FIG. [Figure 6] 10 is a cross-sectional view perpendicular to the width direction of the device, showing the mounting direction relative to the support frame. FIG. [Figure 7] FIG. 10 is a perspective view showing the clip in an unattached state relative to the other end of the rotating shaft. [Figure 8] 6 is a cross-sectional view of the guide portion taken along line TT in FIG. 5, showing the roller unit in a state before the fully attached position. [Figure 9] 6 is a cross-sectional view of the guide portion taken along line TT in FIG. 5, showing the roller unit in a state where it is in the installation completion position. [Figure 10] 6 is a cross-sectional view of the locking mechanism taken along line SS in FIG. 5, showing the locking mechanism in an unlocked state. [Figure 11] 6 is a cross-sectional view of the locking mechanism taken along line SS in FIG. 5, showing the locked state of the locking mechanism. [Figure 12] 6 is a diagram showing the structure of inputting power to the input gear of the roller unit as viewed from a position along line RR in FIG. 5. [Figure 13] 10 is a perspective view showing a configuration in which power is input to a transmission gear as a second power transmission body that indirectly inputs driving force to an input gear. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0012] An embodiment of an image forming apparatus and a roller unit according to the present invention will be described below with reference to the drawings. The following embodiment illustrates various technically preferable configurations for carrying out the present invention. However, the scope of the present invention is not limited to the following embodiment and illustrated examples.

[0013] [Image forming device overview] FIG. 1 is a diagram showing a schematic configuration of an image forming apparatus 100 according to an embodiment of the present invention. 1, the image forming apparatus 100 includes a first sheet S supply unit 101, a second sheet S supply unit 102, an image forming unit 103, and the like. These are stored in an exterior case 104 of the image forming apparatus 100. The image forming apparatus 100 also includes an operation display unit, a control unit, a power supply unit, and the like, which are not shown. In the following description, the directions of the various parts of the image forming apparatus 100 are described on the assumption that the image forming apparatus 100 is placed on a horizontal surface.

[0014] The image forming apparatus 100 prints (forms) a full-color or monochrome image on a sheet S by electrophotography based on image data. The image data is input from an external terminal device or the like via a network (e.g., a LAN), for example. Sheet S generally refers to recording media on which image forming apparatus 100 forms an image. Note that, in the following, the term "sheet" may be referred to as "paper" or "paper sheet," but this does not mean that the sheet is limited to "paper." Sheet S includes various types of recording paper such as plain paper, as well as various sheet-like recording media to be printed on, such as overhead projector sheets.

[0015] 1, the image forming apparatus 100 has a first supply means 101 and a second supply means 102 for the sheet S at the bottom of the apparatus. An image forming unit 103 is provided above the first supply means 101 and the second supply means 102 in the image forming apparatus 100.

[0016] [First supply means] The first supply means 101 has a paper cassette 11 and a plurality of conveying means for feeding the sheets S from the paper cassette 11 onto a conveying path R. The conveying means is, for example, a conveying roller 12. The paper cassette 11 can accommodate various types of sheets S stacked one above the other. The operation of the transport rollers 12 is controlled by a control unit (not shown), and sends out the sheets S to be used for printing onto the transport path R one by one. The number of paper cassettes 11 is not limited to one, and may be more than one. Each paper cassette 11 may contain the same type of sheets S, or may contain sheets S of different paper types.

[0017] The sheet S sent out onto the transport path R from the paper cassette 11 is sent to the registration rollers 13 located before the image forming unit 103. The sheet S hits the registration rollers 13 once and is sent to the image forming unit 103 at an appropriate timing.

[0018] [Image forming section] The image forming unit 103 forms a toner image using toners of multiple colors, and transfers and fixes the toner image onto a sheet S supplied from first and second supply means 101 and 102. The toners of each color are, for example, yellow (Y), magenta (M), cyan (C), black (K), etc. The image forming unit 103 includes an intermediate transfer belt 41 arranged horizontally at the top of the device. The intermediate transfer belt 41 is wound around a pair of belt rotation rollers 42 and 43. The intermediate transfer belt 41 is rotated in the direction indicated by arrow X by a motor (not shown).

[0019] Below the intermediate transfer belt 41, process units 30 are provided, each of which is detachable from the apparatus main body. The process units 30 include process units 30Y, 30M, 30C, and 30K. The process units 30 are arranged in that order along the direction of rotation of the intermediate transfer belt 41. The process unit 30Y includes multiple process means for forming a toner image using yellow (Y) toner. The process unit 30M includes multiple process means for forming a toner image using magenta (M) toner. The process unit 30C includes multiple process means for forming a toner image using cyan (C) toner. The process unit 30K includes multiple process means for forming a toner image using black (K) toner. Each process unit 30 can be removed from the device body by pulling it out toward the front (the front side of the paper in FIG. 1). Also, each process unit 30 can be attached to the device body by inserting it toward the back of the device body. Note that the toner colors are not limited to the four shown here. If toner of another color is used, a process unit that forms a toner image with that toner is further provided. Alternatively, the process unit 30 may be a single color (for example, black (K)) only. Furthermore, when the number of process units 30 is small, an intermediate transfer drum may be used instead of the intermediate transfer belt 41 .

[0020] A toner storage unit (not shown) is provided above each of the process units 30Y, 30M, 30C, and 30K, with the intermediate transfer belt 41 sandwiched between them. Each toner storage unit stores toner of each color: yellow (Y), magenta (M), cyan (C), and black (K). The toner stored in each toner storage unit corresponding to each color is supplied to each process unit 30 by a toner supply mechanism (not shown).

[0021] Each of the process units 30Y, 30M, 30C, and 30K has a photosensitive drum 31 that faces the intermediate transfer belt 41 from below. A photosensitive layer is provided on the surface of each photosensitive drum 31 around the entire circumference, and each photosensitive drum 31 rotates in the direction indicated by arrow Z. A charger 32 is provided downstream in the rotation direction from above the photosensitive drum 31 that faces the intermediate transfer belt 41. The charger 32 uniformly charges the photosensitive layer of the photosensitive drum 31 to a predetermined charging potential.

[0022] Laser beams LY, LM, LC, and LK are emitted from an exposure unit 47 downstream of the charger 32 in the rotation direction of the photosensitive drum 31. The exposure unit 47 is provided with four semiconductor laser elements. Each semiconductor laser element emits laser beams LY, LM, LC, and LK based on image data. Each laser beam LY, LM, LC, and LK is irradiated onto the photosensitive layer of each photosensitive drum 31 via a polygon mirror, a scanning lens, etc. As a result, an electrostatic latent image is formed on the photosensitive layer of each photosensitive drum 31, which has been uniformly charged by each charger 32.

[0023] Each process unit 30 is provided with a developing device 33 downstream in the rotation direction of the photosensitive drum 31 from the exposure position. Each developing device 33 develops the electrostatic latent image formed on the photosensitive layer of each photosensitive drum 31 with toner. The developing device 33 of each process unit 30 develops the toner using a two-component developer containing toner of the corresponding color and a magnetic carrier.

[0024] The photosensitive drum 31, charger 32, and developer 33 in each process unit 30 constitute process means for forming a toner image. The process means provided in each of process units 30Y, 30M, 30C, and 30K have the same configuration in all process units 30. Note that Figure 1 is merely a schematic diagram and does not accurately show the arrangement, shape, etc. of each component.

[0025] Primary transfer rollers 44Y, 44M, 44C, and 44K are provided above each process unit 30. Each of the primary transfer rollers 44Y, 44M, 44C, and 44K is attached to face a corresponding photosensitive drum 31 with the intermediate transfer belt 41 sandwiched therebetween. When a transfer bias voltage is applied to each of the primary transfer rollers 44Y, 44M, 44C, and 44K, an electric field is formed between the rollers and the opposing photosensitive drum 31. As a result, the toner images formed on each photosensitive drum 31 are primarily transferred onto the intermediate transfer belt 41.

[0026] When a full-color image is formed, the toner images formed on the respective photosensitive drums 31 are multiple-transferred to the same area on the intermediate transfer belt 41. The multiple-transfer is performed by appropriately adjusting the timing of the image forming operations of the respective process units 30Y, 30M, 30C, and 30K. On the other hand, when forming a monochrome image, only one selected process unit is used. In this case, for example, process unit 30K for K toner is used. A toner image is formed on the photosensitive drum 31 of that process unit 30K. Then, the toner image is transferred onto a predetermined area of ​​intermediate transfer belt 41 by primary transfer roller 44K facing photosensitive drum 31.

[0027] Although not shown, a cleaning member is provided in each process unit 30. The cleaning member scrapes off residual toner from the surface of each photosensitive drum 31 onto which the toner image has been transferred.

[0028] The intermediate transfer belt 41 transports the transferred toner image to the end of the belt rotation roller 42 (the end on the right side in FIG. 1). A secondary transfer roller 45 is disposed opposite the belt rotation roller 42 with the intermediate transfer belt 41 sandwiched between them. The secondary transfer roller 45 is pressed against the intermediate transfer belt 41, forming a transfer nip between them. A transfer bias voltage is applied to the secondary transfer roller 45. The application of the transfer bias voltage forms an electric field between the secondary transfer roller 45 and the intermediate transfer belt 41. A sheet S fed from a paper cassette 11 of the first supply means 101 to a transport path R is transported to the transfer nip. The toner image transferred onto the intermediate transfer belt 41 is secondarily transferred onto the sheet S transported along the transport path R by the action of the electric field described above.

[0029] The sheet S that has passed through the transfer nip is transported to a fixing device 50 that is arranged above the secondary transfer roller 45. The fixing device 50 includes a heating roller 51 and a pressure roller 52 that are pressed against each other. The heating roller 51 and the pressure roller 52 are pressed against each other to form a fixing nip therebetween. A heating means 511 is arranged at the axial center of the heating roller 51. The heating means 511 is, for example, a heater lamp. The heating roller 51 is heated by the heating means 511. In the fixing device 50, the unfixed toner image on the sheet S is fixed by applying heat and pressure while passing through the fixing nip. The sheet S with the fixed toner image is discharged by a paper discharge roller 14 onto a paper discharge tray 15 disposed above the process unit 30, etc.

[0030] Note that the embodiment has been described above in which the image forming unit 103 of the image forming apparatus 100 forms images by an electrophotographic method. However, the image forming unit of the image forming apparatus may be of another method, such as an inkjet method.

[0031] [Second supply means] FIG. 2 is a perspective view showing the image forming apparatus 100 with the door 105 of the exterior case 104 open. Door 105 is provided on one side surface (the right side of the paper in FIG. 1) of exterior case 104, facing the inner transport path R. Door 105 is supported by one end of exterior case 104 in a direction perpendicular to the paper surface of FIG. 1 (the back side of the paper surface). Furthermore, door 105 is supported by exterior case 104 so as to be rotatable around an axis along the up-down direction of the paper surface of FIG.

[0032] In the following description, the direction perpendicular to the plane of the paper in Fig. 1 is defined as the device width direction W of the image forming apparatus 100 (see Fig. 4). When referring to the device width direction W in the description of the directions of the various parts of the second supply means 102, it is assumed that the door 105 is closed. The device width direction W is also the direction that coincides with the "center line direction of the transport rollers."

[0033] Door 105 is a one-sided door, and when door 105 is opened, the configuration of transport path R in image forming unit 103 is exposed to the outside of exterior case 104. This allows repairs and maintenance of image forming unit 103 to be performed.

[0034] An intake port 105 a for taking in the sheet S into the inside of the exterior case 104 is formed at the bottom of the door 105 . The second supply means 102 is for supplying the sheet S to the transport path R described above through the inlet 105a. The second supply means 102 has an openable / closable sheet tray 106, a sub-transport path R1 for the sheet S, and a transport means 110 for the sheet S on the sub-transport path R1.

[0035] The sheet tray 106 is provided on the outer surface of the door 105, at a position facing the outside of the inlet 105a. The lower end of the sheet tray 106 is supported by the door 105 so as to be rotatable around an axis along the width direction W of the device. When the sheet tray 106 is in an upright position, it closes the inlet 105a. When the upper end of the sheet tray 106 is rotated outward, it opens the inlet 105a to the outside. When the inlet 105a is open, the sheet tray 106 is tilted so that the inlet 105a side is lower, as shown by the two-dot chain line in FIG. 1. In this tilted position, the sheet tray 106 can hold multiple sheets S stacked on it.

[0036] The sub-conveying path R1 is formed from the inlet 105a to the junction at the bottom of the conveying path R. The sub-conveying path R1 joins the conveying path R upstream of the position of the registration rollers 13. Therefore, the sheet S conveyed through the sub-conveying path R1 is also sent to the image forming unit 103 at an appropriate timing by the registration rollers 13.

[0037] Fig. 3 is a cross-sectional view of the lower part of the door 105 taken along line VV in Fig. 2. Fig. 3 is a cross-sectional view of the lower part of the door 105 taken from the same direction as Fig. 1 with the door 105 closed. The conveying means 110 includes a conveying roller 111, an opposing plate 112, a separation roller 113, a conveying guide 114, and a support frame 115. The conveying means 110 further includes a roller unit 60 that is detachable from the support frame 115.

[0038] 1, the transport rollers 111 are arranged at multiple locations along the sub-transport path R1. The transport rollers 111 are made up of a pair of rollers that rotate around an axis along the device width direction W, and transport the sheet S by a drive source (not shown).

[0039] The support frame 115 constitutes an internal frame inside the inlet 105a and a part of the sub-transport path R1 at the bottom of the door 105. The support frame 115 supports the entire structure of the transport means 110.

[0040] The opposing plate 112 is a placing plate on which the leading edge of the sheet S stacked on the sheet tray 106 (not shown in FIG. 3) on the downstream side in the conveying direction is placed. The opposing plate 112 has an upstream end in the conveying direction (right side in FIG. 3) supported by a support frame 115. That is, the opposing plate 112 has the end rotatably supported about an axis along the width direction W of the device. This allows the opposing plate 112 to rotate and move up and down at the downstream end in the conveying direction (left side in FIG. 3). In addition, a pressing spring 116 is provided below the downstream end of the opposing plate 112 in the conveying direction. This presses the downstream end of the opposing plate 112 in the conveying direction upward. Meanwhile, a pick roller 62 held by a roller unit 60 (described later) is disposed opposite to the upper side of the downstream end of the opposing plate 112 in the conveying direction. Therefore, the leading edge of the top sheet S on the opposing plate 112 is pressed against the pick roller 62, making it easy to pick up the sheet S.

[0041] A conveying guide 114 is disposed further downstream in the conveying direction than the downstream end of the opposing plate 112. The conveying guide 114 has an inclined surface that slopes upward toward the downstream side in the conveying direction, and guides the sheet S downstream along the inclined surface. The conveying guide 114 is formed integrally with the support frame 115 inside the support frame 115.

[0042] A separation roller 113 is disposed downstream in the conveying direction of the conveying guide 114. The separation roller 113 is supported by a support frame 115 in a state where it can rotate about an axis along the width direction W of the device. In other words, the center line of the separation roller 113 is parallel to the width direction W of the device. The separation roller 113 is disposed so as to face the conveying roller 61 held by the roller unit 60 attached to the support frame 115. The separation roller 113 forms a nip with the conveying roller 61, and conveys the sheet S through the nip. The separation roller 113 may be disposed so as to abut against the conveying roller 61, as long as the separation roller 113 is capable of conveying the sheet S. The transport roller 61, which will be described later, is driven to rotate by inputting torque. In contrast, the separation roller 113 is rotated by torque transmitted from the transport roller 61 when transporting the sheet S. A torque limiter (not shown) is provided alongside the separation roller 113. The torque limiter applies a rotational resistance force to the separation roller 113. For this reason, the lower sheet S of the stacked sheets S is prevented from being transported by the separation roller 113, and only the top sheet S can be sent downstream.

[0043] [Second supply means: roller unit] Fig. 4 is a perspective view of roller unit 60, and Fig. 5 is a bottom view. Fig. 6 is a cross-sectional view perpendicular to the device width direction W, showing the mounting direction of roller unit 60 to support frame 115. In Figs. 4 and 5, the mounting direction of roller unit 60, which will be described later, is indicated by the symbol M. The roller unit 60 includes a transport roller 61, a pick roller 62, a housing 63, a guide portion 64, a locking mechanism 65, and the like. In the following, all descriptions of the directions of the various parts of roller unit 60 are based on the assumption that roller unit 60 is attached to image forming apparatus 100. Unless otherwise specified, it is also based on the assumption that door 105 is closed.

[0044] The housing 63 is a box body integrally including a sloped surface 631, a top surface 632, first to fourth side surface portions 633 to 636, and inner side surface portions 637 and 638. The bottom of the housing 63 is widely open.

[0045] The inclined surface portion 631 is made of a substantially rectangular flat plate that is parallel to the mounting direction M of the roller unit 60 to the support frame 115 (described later) and the device width direction W. The lower end of the inclined surface portion 631 is curved slightly downward over the entire length in the device width direction W. When roller unit 60 is attached to support frame 115, inclined surface 631 forms part of the exterior of image forming apparatus 100. In other words, inclined surface 631 is exposed to the outside when sheet tray 106 is open, and forms part of the outer wall of image forming apparatus 100.

[0046] Top surface 632 is made of a horizontal flat plate connected to the upper end of inclined surface 631. Top surface 632 is slightly wider in the device width direction W than inclined surface 631. Top surface 632 protrudes on both sides in the device width direction W beyond inclined surface 631.

[0047] The first side surface portion 633 and the second side surface portion 634 are individually connected to one end and the other end of the inclined surface portion 631 in the device width direction W. Both the first side surface portion 633 and the second side surface portion 634 hang down. Both the first side surface portion 633 and the second side surface portion 634 are flat plates that are perpendicular to the device width direction W. The third side surface portion 635 and the fourth side surface portion 636 are individually connected to one end and the other end of the top surface portion 632 in the device width direction W. Both the third side surface portion 635 and the fourth side surface portion 636 hang down. Both the third side surface portion 635 and the fourth side surface portion 636 are flat plates that are perpendicular to the device width direction W.

[0048] The inner side surface portion 637 is provided inside the housing 63 and directly faces the first side surface portion 633. The inner side surface portion 637 hangs down from the inclined surface portion 631. The inner side surface portion 637 is a flat plate that is perpendicular to the width direction W of the device. Internal side surface portion 638 is provided inside housing 63 directly opposite third side surface portion 635. Internal side surface portion 638 hangs down from top surface portion 632. Internal side surface portion 638 is a flat plate that is perpendicular to the width direction W of the device.

[0049] The transport roller 61 is disposed below the top surface portion 632 and between the fourth side surface portion 636 and the inner side surface portion 638 . The transport roller 61 is cylindrical. The transport roller 61 is supported by the housing 63 so that a lower part of the outer periphery of the transport roller 61 protrudes downward. As a result, the outer periphery of the transport roller 61 contacts the sheet S when rotating, thereby transporting the sheet S.

[0050] A rotating shaft 611 is inserted through the center of the transport roller 61. The rotating shaft 611 is connected to the transport roller 61 via a one-way clutch 612. The one-way clutch 612 transmits torque to the transport roller 61 only when the rotating shaft 611 rotates in a direction corresponding to the transport direction. The rotation shaft 611 passes through the fourth side surface portion 636 and the inner side surface portion 638 and is rotatably supported by them. The center lines of the rotation shaft 611 and the transport roller 61 are parallel to the width direction W of the device. One end of the rotation shaft 611 protrudes largely from the fourth side surface portion 636 to the outside of the roller unit 60. An input gear 613 serving as an input portion is fixedly mounted on one end of the rotation shaft 611. The input gear 613 receives an input of a driving force that rotates the transport roller 61. The input gear 613 receives the driving force from the main body side of the image forming apparatus 100. An output gear 614 is provided on the rotation shaft 611 between the fourth side surface portion 636 and the transport roller 61 to transmit the torque of the rotation shaft 611 to the outside.

[0051] Furthermore, a clip 66 is attached to the other end of the rotating shaft 611 between the third side surface portion 635 and the inner side surface portion 638 to prevent it from coming off. FIG. 7 is a perspective view showing the clip 66 in an unattached state to the other end of the rotary shaft 611. As shown in FIG. At the other end of the rotating shaft 611, a mounting groove 615 for mounting a clip 66 is formed around the outer circumferential surface of the rotating shaft 611. Clip 66 has an annular portion 661 and a knob 662. Annular portion 661 is a flat ring-shaped portion whose inner diameter is slightly larger than the outer diameter of the bottom surface of attachment groove 615. Knob 662 is a handle for clip 66. The annular portion 661 has a divided portion 663 formed by cutting out a portion of the ring. The clip 66 is formed from a flexible material such as resin. Therefore, the portion of the rotating shaft 611 whose diameter is reduced by the mounting groove 615 can be pushed inward from the divided portion 663 to the center of the clip 66. The clip 66 employs a snap-fit ​​structure that allows it to be attached to and detached from the mounting groove 615 of the rotating shaft 611 without the need for tools. The knob 662 is erected on one surface of the annular portion 661, on the diametrically opposite side of the dividing portion 663. Therefore, when attaching or detaching the clip 66 to or from the mounting groove 615, the knob 662 can be grasped and the clip can be easily pushed in or pulled out.

[0052] A stopper (not shown) is provided on the rotating shaft 611. This stopper prevents the rotating shaft 611 from moving further toward the third side surface portion 635 than the position shown in Fig. 5 relative to the housing 63. The rotating shaft 611 is restricted by a clip 66 from moving further toward the input gear 613 than the mounting position shown in Fig. 5. Therefore, when the clip 66 is pulled out from the rotating shaft 611, the entire rotating shaft 611 can be pulled out toward the input gear 613 from the housing 63. At that time, the rotating shaft 611 can also be pulled out from the conveying roller 61, the one-way clutch 612, and the output gear 614. That is, the transport roller 61, the one-way clutch 612, and the output gear 614 are detachably held in the housing 63 by a snap-fit ​​structure.

[0053] The pick roller 62 is disposed below the inclined surface portion 631 and between the second side surface portion 634 and the inner side surface portion 637 . The pick roller 62 is cylindrical. The pick roller 62 is supported by the housing 63 so that a portion of the lower side of the outer periphery of the pick roller 62 protrudes downward. This allows the outer periphery of the pick roller 62 to abut against the upper surface of the opposing plate 112 or the sheet S on the opposing plate 112. The pick roller 62 has countless grooves formed on its outer periphery that are aligned in the circumferential direction along the width direction W of the device. The grooves enable the pick roller 62 to pick up the sheet S with high frictional force.

[0054] A rotation shaft 621 is inserted through the center of the pick roller 62 . The rotation shaft 621 is connected to the pick roller 62 so that torque can be transmitted thereto. The rotation shaft 621 passes through the second side surface portion 634 and the inner side surface portion 637 and is rotatably supported by them. The center lines of the rotation shaft 621 and the pick roller 62 are parallel to the width direction W of the device. One end of the rotation shaft 621 protrudes slightly from the second side surface portion 634 to the outside of the roller unit 60 . An input gear 624 is fixedly mounted on the rotary shaft 621 between the second side surface portion 634 and the pick roller 62. The input gear 624 receives torque from the outside and transmits it to the rotary shaft 621.

[0055] Furthermore, a clip 66 that prevents the rotating shaft 621 from coming off is attached to the other end of the rotating shaft 621 between the first side surface portion 633 and the inner side surface portion 637. This clip 66 is the same as the clip 66 provided on the rotating shaft 611. Therefore, the clip 66 can be attached to and detached from a mounting groove (not shown) formed on the other end of the rotating shaft 621 without using any tools.

[0056] A stopper (not shown) is also provided on the rotating shaft 621. This stopper prevents the rotating shaft 621 from moving toward the first side surface portion 633 relative to the housing 63 beyond the mounting position shown in Fig. 5. The rotating shaft 621 is prevented from being pulled out of the housing 63 by a clip 66. Therefore, when the clip 66 is pulled out from the rotating shaft 621, the entire rotating shaft 621 can be pulled out from the housing 63 in the same direction as the rotating shaft 611. At that time, the rotating shaft 621 can also be pulled out from the pick roller 62 and the input gear 624. That is, the pick roller 62 and the input gear 624 are also detachably held in the housing 63 by a snap-fit ​​structure.

[0057] Furthermore, a transmission gear 67 that meshes with an output gear 614 of the rotary shaft 611 and an input gear 624 of the rotary shaft 621 is provided inside the housing 63. As a result, when torque is input to the rotary shaft 611 via the input gear 613, the torque is also transmitted to the rotary shaft 621. This structure allows the transport roller 61 and the pick roller 62 to rotate in the same direction in an interlocking manner.

[0058] 5 and 6, a plurality of transport guides 639 are provided upstream of the transport roller 61 in the mounting direction M in the housing 63. Each transport guide 639 is formed integrally with the housing 63. Each transport guide 639 is a convex strip extending along the mounting direction M. A protruding tip surface of each transport guide 639 comes into contact with the sheet S to guide the sheet S in the transport direction.

[0059] Figures 8 and 9 are cross-sectional views of the guide portion 64, the locking mechanism 65, and the holding structure of the roller unit 60 on the support frame 115 side. Figures 8 and 9 are cross-sectional views taken along line TT in Figure 5. Figures 10 and 11 are cross-sectional views taken along line SS in Figure 5 of the same configuration as in Figures 8 and 9.

[0060] The guide section 64 has flat guide plates 641, 642 that extend individually from both ends of the housing 63 in the device width direction W to both sides in the device width direction W. When viewed from the device width direction W, the guide plates 641, 642 both extend along the mounting direction M of the roller unit 60. The downstream ends of the guide plates 641, 642 in the mounting direction M bulge uniformly into a circular cross section across the entire width in the device width direction W.

[0061] 8, when viewed from the device width direction W, the guide plate 641 or its extension is arranged so as not to intersect with the center line 61c of the transport roller 61. Although not shown, the same applies to the guide plate 642.

[0062] On the other hand, the support frame 115 is formed with an insertion slot 117 (see FIGS. 2 and 3) for inserting the roller unit 60. This insertion slot 117 is provided on the inner surface side of the door 105 in a state where it opens upward. Guide grooves 118 are provided on surfaces of the insertion slot 117 that face both ends of the roller unit 60 in the device width direction W. Note that only the guide groove 118 that corresponds to the guide plate 641 is shown in Figures 8 and 9, and the guide groove that corresponds to the guide plate 642 is not shown.

[0063] The guide groove 118 is open on the guide plate 641 side and at its upper end. The guide groove 118 can receive the tip of the guide plate 641 from above. The guide groove 118 is formed along the mounting direction M, and its terminal end is closed in a semicircular shape. From the upper end to the middle of the guide groove 118, the groove width is wider than the tip of the guide plate 641 in the mounting direction. The groove width of the guide groove 118 gradually decreases from the middle. From just before the terminal end of the guide groove 118 to the terminal end, the groove width is approximately equal to the width of the tip of the guide plate 641. Further, the guide groove corresponding to the guide plate 642 has the same structure as the guide plate 642 .

[0064] As a result, when roller unit 60 is inserted into insertion slot 117, it is guided in the correct orientation by guide plates 641, 642 and guide groove 118. In other words, roller unit 60 can be installed with guide plates 641, 642 aligned with installation direction M. Furthermore, the terminal end of guide groove 118 can position roller unit 60 at an appropriate position. The appropriate position is a position where pick roller 62 abuts or faces opposing plate 112, and transport roller 61 abuts or faces separation roller 113. Note that it is desirable for pick roller 62 and transport roller 61 to be in close proximity with a gap of no more than one sheet S or less. Note that the position where roller unit 60 is inserted into insertion slot 117 until this abutting or facing state is reached is the "installation completion position" of roller unit 60.

[0065] 6, the relationship between the mounting direction M of the roller unit 60 and the conveying direction of the sheet S by the roller unit 60 will be described. In the following description, the conveying direction of the sheet S by the conveying roller 61 and the separation roller 113 is referred to as the conveying direction F. Furthermore, on a plane perpendicular to the device width direction W, the line segment connecting the center of the separation roller 113 and the center of the conveying roller 61 is indicated by the symbol P1.

[0066] The center line of the transport roller 61 is parallel to the device width direction W. Therefore, the transport direction F of the transport roller 61 is perpendicular to the device width direction W. The transport direction F is also perpendicular to the line segment P1 on a plane perpendicular to the device width direction W. In contrast, on a plane perpendicular to the device width direction W, the mounting direction M is a direction generally parallel to the conveying direction F. More specifically, the mounting direction M is set to intersect with the line segment P1 at an angle θ of 90° or more. The mounting direction M and the line segment P1 form four corners at their intersections. The angle θ here refers to the angle of the intersection on the upstream side of the roller unit 60 in the mounting direction M and on the separation roller 113 side relative to the conveying roller 61. It is preferable that the angle θ between the mounting direction M and the line segment P1 does not deviate significantly from 90°. The angle θ is preferably within a range of +30° from 90°. Furthermore, the angle θ is more preferably within a range of +15° from 90°.

[0067] Due to the configuration of the guide portion 64, the roller unit 60 can be attached to the image forming apparatus 100 facing the upstream side in the conveying direction F of the sheet S.

[0068] As shown in FIGS. 4, 5, 10 and 11, the locking mechanism 65 includes a handle 651, a hinge portion 652, and a locking pin 653. The handle 651 is provided on the top surface 632 of the housing 63 via two hinge portions 652. The handle 651 is supported by the two hinge portions 652 so as to be rotatable around an axis parallel to the width direction W of the device. The handle 651 has a width in the device width direction W that is approximately equal to the length from the tip of one guide plate 641 to the tip of the other guide plate 642. The handle 651 can be oriented upstream in the mounting direction M on the upper surface of the top surface 632. The handle 651 can be in an upright state extending from the rotation center C of each hinge portion 652 toward the upstream side in the mounting direction M. When viewed from the device width direction W, the handle 651 in the standing state is on the same straight line as the guide plate 641 along the mounting direction M (see FIG. 8).

[0069] The rotating end of the handle 651 is restricted by a stopper (not shown) so as not to rotate from the standing state toward the separation roller 113 relative to the conveying roller 61. On the other hand, the rotating end of the handle 651 can rotate within a range of 90° from the standing state toward the conveying roller 61 relative to the separation roller 113 (see FIG. 10). This rotation range is also restricted by another stopper (not shown).

[0070] The handle 651 is provided at the upstream end of the roller unit 60 in the mounting direction M. Furthermore, the rotating end of the handle 651 can be raised toward the upstream side in the mounting direction M. The handle 651 is restricted from rotating from the raised state toward the separation roller 113 side relative to the conveyance roller 61. Therefore, the roller unit 60 can be smoothly mounted on the support frame 115 by grasping the handle 651 with one hand.

[0071] Furthermore, the handle 651 is provided with a pair of lock pins 653 that protrude outward from both ends in the device width direction W. Each lock pin 653 has a generally cylindrical shape that is aligned with the device width direction W. The basic shape of a cross section of each lock pin 653 perpendicular to the device width direction W is circular. More specifically, the cross section of each lock pin 653 has a shape in which two places on the outer periphery of a circle have been removed by two parallel straight lines that are spaced apart more closely than the diameter of the circle. Note that these two straight lines are both equidistant from the center of the circle. The center of the cross-sectional shape of each lock pin 653 is arranged so as to be concentric with the center of rotation C of hinge portion 652 of handle 651. Furthermore, the two straight line portions of the cross-sectional shape of each lock pin 653 are parallel to the extension direction of handle 651.

[0072] Furthermore, inside the insertion slot 117, on surfaces facing both sides of the roller unit 60 in the device width direction W, there are provided holding portions 119 for the lock pin 653. Note that only the holding portion 119 that receives the lock pin 653 that protrudes in the same direction as the guide plate 641 is shown in Figures 10 and 11. Furthermore, the holding portion that receives the lock pin 653 that protrudes in the same direction as the guide plate 642 is not shown.

[0073] The holding portion 119 is disposed slightly further away from the roller unit 60 in the device width direction W than the guide groove 118 described above. This prevents the holding portion 119 from interfering with the tip of the guide plate 641 when the roller unit 60 is attached. The holding portion 119 has a receiving recess 119a for the lock pin 653 that is circular when viewed in the device width direction W. The inner diameter of the receiving recess 119a of the holding portion 119 is equal to or slightly larger than the outer diameter of the lock pin 653. Furthermore, the holding portion 119 is open on the roller unit 60 side. Furthermore, the holding portion 119 has an opening on the upstream side in the mounting direction M. The opening width of the opening of the holding portion 119 in a direction perpendicular to the mounting direction M is equal to the distance between the two straight portions in the cross-sectional shape of the lock pin 653. Strictly speaking, the opening width of the holding portion 119 is slightly larger than the distance between the two straight portions of the lock pin 653. Furthermore, the holding portion for receiving the lock pin 653 on the guide plate 642 side has the same structure as the lock pin 653 .

[0074] As shown in Figure 10, roller unit 60 is attached to support frame 115 through insertion slot 117. Then, lock pins 653 are housed in receiving recesses 119a through the openings of holder 119. This causes the center of the cross-sectional shape of each lock pin 653 (rotation center C of handle 651) to become concentric with the center of receiving recesses 119a. In this state, roller unit 60 reaches the attachment completion position described above. In this state, the rotating end of handle 651 is rotated 90 degrees toward conveyance roller 61 relative to separation roller 113. Then, as shown in FIG. 11 , lock pin 653 also rotates 90 degrees in the same direction within receiving recess 119a. As a result, the width of lock pin 653 becomes wider than the opening width of the opening of holding portion 119 in the direction perpendicular to installation direction M. Therefore, holding portion 119 and lock pin 653 restrict movement of roller unit 60 upstream in installation direction M. Roller unit 60 is held in the installation completion position and is fixed to image forming apparatus 100. When removing the roller unit 60, the handle 651 is rotated to an upright position. This allows the lock pin 653 to be removed from the holder 119, and the roller unit 60 to be pulled out of the insertion slot 117. In other words, the upright position of the handle 651 corresponds to the unlocked state of the locking mechanism 65. In this way, the handle 651 also functions as an operating part for holding the roller unit 60 by the locking mechanism 65.

[0075] When viewed from the device width direction W, the rotation center C of the handle 651 is located upstream of the center of gravity G of the roller unit 60 in the mounting direction M (see FIG. 9). Therefore, when the handle 651 is held by hand, the handle 651 remains upright, and the downstream end of the roller unit 60 in the mounting direction M faces downward. This allows the roller unit 60 to be oriented in a position that makes it easy to insert the roller unit 60 into the insertion slot 117. Furthermore, when the handle 651 is in an upright position facing upstream in the mounting direction M, the locking mechanism 65 is in a released state (see FIG. 10). Therefore, roller unit 60 can be easily inserted to the installation completion position while holding handle 651. In other words, by holding handle 651, roller unit 60 can be installed without the need for operations such as setting lock mechanism 65 to the unlocked state.

[0076] [Configuration for inputting driving force to the roller unit] Here, a configuration for inputting a driving force to roller unit 60 mounted in image forming apparatus 100 will be described. Figure 12 is a view of the power input structure for input gear 613 of roller unit 60, seen from a position along line RR in Figure 5. As shown in the figure, an idle gear 120 is provided inside insertion slot 117 on the surface facing fourth side surface portion 636 of roller unit 60. This idle gear 120 is a first power transmission member that meshes with input gear 613 when roller unit 60 is installed, and directly inputs driving force. A line segment connecting the center of the input gear 613 of the roller unit 60 and the center of the idle gear 120 on a plane perpendicular to the device width direction W is defined as P2. The roller unit 60 is installed in the insertion slot 117. This line segment P2 is set to be perpendicular to the installation direction M. As a result, simply by mounting the roller unit 60 to the support frame 115 in the mounting direction M, the input gear 613 and the idle gear 120 are meshed well with each other.

[0077] FIG. 13 is a perspective view showing a configuration in which power is input to a transmission gear 121 serving as a second power transmission body that indirectly inputs driving force to the input gear 613. In FIG. The transmission gear 121 is disposed on the door 105 at the end supported by the exterior case 104. The transmission gear 121 is coaxially connected to the idle gear 120 described above. Torque input to this transmission gear 121 enables the transport roller 61 to be driven via the idle gear 120 and the input gear 613.

[0078] A drive source (not shown) of the output gear 122 that inputs torque to the transmission gear 121 is disposed on the exterior case 104 side, not inside the door 105. As shown in FIG. 13 , the output gear 122, which is driven by the drive source, is disposed in the exterior case 104 near the support end of the door 105. The output gear 122 is disposed so as to mesh with the transmission gear 121 when the door 105 is closed in the direction of the arrow. In other words, when the door 105 is open, torque cannot be transmitted from the output gear 122 to the transmission gear 121. As a result, the input of drive force from the transmission gear 121 to the idle gear 120 and the input gear 613 is cut off. On the other hand, the insertion slot 117 for the roller unit 60 is provided on the inner side of the door 105. For this reason, the roller unit 60 must be attached or detached with the door 105 open. Therefore, when attaching or detaching the roller unit 60, the input of driving force to the input gear 613 is cut off. This prevents the roller unit 60 from being accidentally driven when attached or detached, improving the ease of attachment and detachment.

[0079] [Operation of image forming apparatus and image forming method] Next, the operation of image forming apparatus 100, including the installation of roller unit 60, will be described. The worker opens the door 105 and inserts the roller unit 60 into the insertion slot 117 in a state where the driving force is disconnected, and then mounts the roller unit 60. At this time, the worker holds the handle 651 with his / her hand and inserts the roller unit 60 into the insertion slot 117 with the pick roller 62 side facing downward. The guide plates 641, 642 of the roller unit 60 are inserted into the guide grooves 118 (FIG. 8). Each guide groove 118 guides the guide plates 641, 642 so that they are parallel to the installation direction M. This insertion causes the tips of the guide plates 641, 642 to reach the bottom of the guide grooves 118 (FIG. 9). Then, the operator rotates the handle 651 by 90° (FIG. 10) to fix the roller unit 60 at the installation position within the insertion slot 117 (FIG. 11). When the door 105 is closed, the output gear 122 and the transmission gear 121 mesh with each other, and the transport rollers 61 of the roller unit 60 are put into a state in which they can be driven. To remove roller unit 60, door 105 is opened and handle 651 is rotated upright to release the lock. Then, roller unit 60 is pulled out in the opposite direction of mounting direction M.

[0080] The following describes an example in which sheets S are supplied from the second supply means 102. The sheet tray 106 is rotated to an inclined state. Then, multiple sheets S are stacked on the upper surface of the sheet tray 106. At this time, the leading ends of the stacked sheets S are inserted between the opposing plate 112 and the pick roller 62. When a driving force is input to the roller unit 60, the pick roller 62 rotates, and the top sheet S is transported downstream. The sheet S is transported further downstream by the nip between the transport roller 61 and the separation roller 113. The separation roller 113 is rotated by the transport roller 61, but is given a certain rotational resistance force. Therefore, when multiple sheets S are transported overlapping each other, the lower sheet S is separated by the separation roller 113, preventing double feeding.

[0081] Then, the sheet S is transported in the sub-transport path R1 by transport rollers 111, and is transported into the transport path R at the junction. Once in the transport path R, the sheet S is transported by transport rollers 12 and temporarily stops just before the registration rollers 13. The registration rollers 13 then send the sheet S to the image forming unit 103 at the appropriate timing. The image forming operation on the sheet S in the image forming unit 103 has been described in the explanation of the configuration of the image forming unit 103, and will not be described here. Then, the sheet S on which the image has been formed is discharged onto the discharge tray 15, and the entire operation of the image forming apparatus 100 is completed.

[0082] [Technical Effects of the Embodiments of the Invention] As described above, the image forming apparatus 100 according to this embodiment has a roller unit 60 that is detachable from the image forming apparatus 100. The roller unit 60 can be attached to the image forming apparatus 100 simply by moving it upstream in the conveyance direction F of the sheet S. The roller unit 60 does not require movement along the center line of the conveyance roller 61 when attaching or detaching it to or from the image forming apparatus 100. This differs from conventional techniques in which the image forming apparatus 100 and roller unit 60 require movement in two different directions when attached. That is, the roller unit 60 can be attached to and detached from the image forming apparatus 100 much more easily than in the prior art.

[0083] Furthermore, the roller unit 60 is provided with a locking mechanism 65 that fixes the roller unit 60 at a predetermined position relative to the image forming apparatus 100. This makes it possible to stably hold the roller unit 60 in an appropriate position.

[0084] The handle 651 also functions as an operating portion that, when rotated, causes the locking mechanism 65 to fix the roller unit 60 to the image forming apparatus 100 . Therefore, roller unit 60 can be easily fixed to image forming apparatus 100 by rotating handle 651. In particular, when roller unit 60 is attached by holding handle 651, handle 651 can be rotated to lock it. When removing roller unit 60, the lock is released by holding handle 651 and rotating it, and roller unit 60 can be pulled out while still holding handle 651. Therefore, extremely high operability is exhibited when attaching and detaching roller unit 60. Furthermore, the handle 651 can be used as a part of the locking mechanism 65, which makes it possible to reduce the number of parts.

[0085] When viewed from the device width direction W, the roller unit 60 is arranged such that the guide plate 641 is aligned with the handle 651 in the upright state on the same line along the mounting direction M. The same is true for the guide plate 642. As a result, when attaching or detaching the roller unit 60, the handle 651 extending rearward can be held to easily insert or pull out the roller unit 60 into or from the insertion slot 117. This makes it extremely easy to attach or detach the roller unit 60.

[0086] Furthermore, roller unit 60 is arranged such that rotation center C of handle 651 is located upstream in mounting direction M with respect to center of gravity G of roller unit 60. Handle 651 is set to be released from locking by locking mechanism 65 when facing upstream in mounting direction M from rotation center C. When roller unit 60 is attached or detached, when handle 651 is held, the entire roller unit 60 faces downward in accordance with center of gravity G. In this state, handle 651 faces upstream in mounting direction M, bringing the unit into an unlocked state. Therefore, by orienting roller unit 60 in a direction suitable for attachment or detachment, the unlocked state is maintained, making attachment or detachment extremely easy.

[0087] When viewed from the device width direction W, the roller unit 60 has guide plates 641, 642 extending along the mounting direction M. Therefore, the roller unit 60 can be mounted and detached along the proper mounting direction M, making the mounting and detaching work extremely easy and proper.

[0088] When viewed from the width direction W of the device, the roller unit 60 is arranged so that the guide plates 641, 642 do not overlap the center line 61c of the transport roller 61. A configuration for driving the rotation of the transport roller 61 is arranged on the center line 61c of the transport roller 61. For this reason, the roller unit 60 tends to become larger in the width direction W of the device. Therefore, by arranging the guide plates 641, 642 so that they do not overlap the center line 61c, the roller unit 60 can be made smaller in the width direction W of the device.

[0089] The roller unit 60 is equipped with an input gear 613 that receives a driving force from the image forming apparatus 100 to rotate the transport roller 61. This eliminates the need to install a motor or other drive source in the roller unit 60, reducing the amount of materials discarded when the roller unit 60 is discarded or replaced. This also contributes to making the roller unit 60 more compact. Furthermore, the configuration can be simplified because there is no need to supply power to the roller unit 60. Also, since there is no need to bother with connecting a power source, the roller unit 60 can be attached and detached extremely easily.

[0090] When viewed from the device width direction W, the roller unit 60 has an angle θ of 90° or more between the mounting direction M and a line segment P1 connecting the centers of the rollers. In this case, the angle is on the separation roller 113 side of the conveying roller 61, and is an angle on the upstream side of the mounting direction M. As a result, the transport roller 61 and separation roller 113 can easily be positioned appropriately for transport by moving the roller unit 60 in the mounting direction M. Therefore, it is possible to provide a roller unit 60 that is suitable for mounting by moving only in the mounting direction M, without requiring axial movement of the rollers.

[0091] The transport roller 61 of the roller unit 60 is detachable. Therefore, when the transport roller 61 deteriorates or breaks, it becomes possible to replace only the transport roller 61. This reduces the frequency with which the entire roller unit 60 needs to be replaced, and reduces the amount of waste material that would result from replacement.

[0092] Furthermore, the transport roller 61 is detachably held by a snap-fit ​​structure, so that no tools are required when replacing the transport roller 61, which makes it possible to facilitate the replacement work, shorten the work time, and reduce the workload.

[0093] When the roller unit 60 is attached, the housing 63 forms part of the exterior of the image forming apparatus 100. This makes it possible to reduce the amount of exterior materials used in the image forming apparatus 100. It also makes it possible to omit part of the exterior, simplifying the structure of the exterior.

[0094] Furthermore, when the roller unit 60 is attached, a part of the housing 63 functions as a conveyance guide 639 for the sheet S. This eliminates the need for a dedicated member as the conveyance guide 639, making it possible to reduce the number of parts and simplify manufacturing.

[0095] Image forming apparatus 100 is equipped with idle gear 120 that inputs a driving force to roller unit 60. When roller unit 60 is attached, it is set so that attachment direction M and line segment P2 connecting the centers of the gears are perpendicular to each other when viewed from the device width direction W. As a result, the input gear 613 and the idle gear 120 mesh well simply by mounting the roller unit 60 in the mounting direction M. Therefore, it is not necessary to move the roller unit 60 in the axial direction when mounting the roller unit 60. Furthermore, it is possible to provide an image forming apparatus 100 that is suitable for mounting the roller unit 60 by moving it only in the mounting direction M.

[0096] Image forming apparatus 100 is equipped with a transmission gear 121 that inputs a driving force to roller unit 60. When door 105 is open, this transmission gear 121 is in a state where the input of the driving force to input gear 613 is cut off. On the other hand, roller unit 60 cannot be attached or detached unless door 105 is in an open state. As a result, the input of driving force to the input gear 613 is kept disconnected when attaching or detaching the roller unit 60. This prevents accidental driving when attaching or detaching the roller unit 60, and makes it possible to improve the workability when attaching or detaching the roller unit 60.

[0097] [others] The above describes various embodiments of the present invention. However, the present invention is not limited to the above embodiments. For example, in the embodiments, a component integrally formed from a single member may be replaced with a component divided into multiple members that are connected or fixed to each other. Furthermore, a component formed by connecting multiple members may be replaced with a component integrally formed from a single member. In addition, the details shown in the embodiments may be modified as appropriate without departing from the spirit of the invention.

[0098] For example, the transport roller 61 can be removed without tools by attaching the rotary shaft 611 with a snap-fit ​​structure. This snap-fit ​​structure is realized by a clip 66, but is not limited to this. For example, any structure that does not require tools may be used, such as inserting and removing a flexible connecting pin into a through-hole that penetrates the rotary shaft 611 in the diameter direction. Although the work becomes somewhat more complicated, the transport roller 61 may be made detachable using a tool. The above example is also applicable to the pick roller 62.

[0099] The locking mechanism is not limited to the configuration of the locking mechanism 65. For example, various members that can be connected and disconnected, such as a slide pin that fixes the roller unit 60 in the insertion slot 117, can be used as the locking mechanism. In addition, the locking mechanism 65 may be operated by a member other than the handle 651. Furthermore, it is preferable that the locking mechanism be one that can be connected and disconnected with a single operation, for example, one that requires fewer members and configurations.

[0100] In the roller unit 60, the driving force to the input gear 613 is cut off when the door 105 is opened by the arrangement of the transmission gear 121 and the output gear 122. However, the present invention is not limited to this. For example, a configuration may be adopted in which the open state of the door 105 is detected by a sensor, and the operation of the drive source of the input gear 613 is controlled based on the detection.

[0101] Furthermore, the roller unit 60 is not limited to use when taking in sheets S from outside the exterior case 104. For example, the roller unit 60 may be disposed inside the exterior case 104 in order to pick up sheets S on a tray built into the exterior case 104. In that case, the roller unit 60 can be replaced by opening a door or the like of the exterior case 104.

[0102] Furthermore, roller unit 60 is not limited to being arranged so as to be detachable from the inner surface of door 105 of exterior case 104. For example, roller unit 60 may be arranged so as to be detachable from the outer surface of door 105, so that it can be attached and detached without opening door 105. Alternatively, roller unit 60 may be arranged so as to be detachable from the outside of exterior case 104. [Explanation of symbols]

[0103] 11 Paper cassette 12 Transport roller 13 Resist Roller 14 Paper ejection roller 15 Paper output tray 30 Process Unit 31 Photosensitive drum 32 Charger 33 Developer 41 Intermediate transfer belt 42 Belt Circumference Roller 45 Secondary transfer roller 47 Exposure device 50 Fixing device 51 Heating roller 52 Pressure roller 60 Roller unit 61 Transport roller 61c center line 611 Rotating shaft 612 One-way clutch 613 Input gear (input part) 614 Output Gear 615 Mounting groove 62 Pick roller 621 Rotating Axis 624 Input Gear 63 Case 631 Slope 632 Top section 633 First side part 634 Second side part 635 Third side part 636 Fourth side part 637,638 Internal side part 639 Transport Guide 64 Guide part 641,642 Guide plate 65 Locking mechanism 651 Handle (operation part) 652 Hinge part 653 Lock pin 66 clips 661 Circular section 662 Picking 663 Divided part 67 Transmission gear 100 Image forming device 101 First supply means 102 Second supply means 103 Image forming unit 104 outer case 105 Door 105a intake 106 Sheet Tray 110 Means of transport 111 Transport roller 112 opposing plate 113 Separation roller 114 Transport guide 115 Support Frame 116 Compression spring 117 Insertion Slot 118 Guide groove 119 Holding part 119a Recess 120 Idle gear (first power transmission body) 121 Transmission gear (second power transmission body) C Rotation center F Conveying direction G center of gravity M Mounting direction P1,P2 line segment R Transport route R1 Sub-transport route S seat W Device width direction θ angle

Claims

1. A roller unit detachable from an image forming apparatus, the roller unit comprising a conveying roller that faces or contacts a separation roller provided in the image forming apparatus to convey a sheet, a roller unit that can be attached to the image forming apparatus toward an upstream side in a conveying direction of the sheet by the separation roller and the conveying roller;

2. The roller unit according to claim 1 , further comprising a locking mechanism that fixes the roller unit to the image forming apparatus at a position where the transport roller faces or abuts against the separation roller.

3. The roller unit according to claim 2 , wherein the handle of the roller unit functions as an operating portion that, when rotated, fixes the roller unit to the image forming apparatus using the locking mechanism.

4. a guide portion for mounting the image forming apparatus to the image forming apparatus; The roller unit according to claim 3 , wherein the guide portion and the handle are arranged side by side on the same line along a mounting direction of the roller unit to the image forming apparatus when viewed from the center line direction of the transport roller.

5. a rotation center of the handle is disposed on the upstream side of the center of gravity of the roller unit in the mounting direction of the roller unit; The roller unit according to claim 3 , wherein the roller unit is released from being fixed by the locking mechanism when the handle faces upstream of the rotation center in the mounting direction of the roller unit.

6. a guide portion for mounting the image forming apparatus to the image forming apparatus; The roller unit according to claim 1 , wherein the guide portion extends along a mounting direction of the roller unit relative to the image forming apparatus when viewed from the center line direction of the transport roller.

7. a guide portion for mounting the image forming apparatus to the image forming apparatus; The roller unit according to claim 1 , wherein the guide portion is disposed so that, when viewed from the direction of the center line of the transport roller, the guide portion or an extension thereof does not overlap the center line of the transport roller.

8. The roller unit according to claim 1 , further comprising an input section that receives an input of a driving force for rotating the transport roller from the image forming apparatus.

9. 2. The roller unit according to claim 1, wherein, when viewed from the center line direction of the transport roller, an angle formed by the mounting direction of the roller unit relative to the image forming apparatus and a line segment connecting the center of the separation roller and the center of the transport roller, the angle on the separation roller side relative to the transport roller and upstream of the mounting direction, is 90° or greater.

10. The roller unit according to claim 1 , wherein the transport roller is detachable from the roller unit.

11. The roller unit according to claim 10 , wherein the transport roller is removably held by a snap-fit ​​structure.

12. The roller unit according to claim 1 , wherein the housing of the roller unit forms part of the exterior of the image forming apparatus when the roller unit is attached to the image forming apparatus.

13. The roller unit according to claim 1 , wherein a housing of the roller unit functions as a transport guide for the sheet transported by the transport roller when the roller unit is attached to the image forming apparatus.

14. An image forming apparatus comprising the roller unit according to claim 1 .

15. An image forming apparatus comprising the roller unit according to claim 8, a first power transmission body that directly inputs a driving force to the input portion from outside the roller unit; an image forming apparatus in which, as viewed from the center line direction of the input portion, the mounting direction of the roller unit and a line segment connecting the center of the input portion and the center of the first power transmission body are perpendicular to each other;

16. An image forming apparatus comprising the roller unit according to claim 8, a second power transmission body that directly or indirectly inputs a driving force to the input portion from outside the roller unit; an openable door having a mounting portion for the roller unit; With the door open, the roller unit can be attached to the attachment section, When the door is open, the image forming apparatus is in a state where the input of the driving force from the second power transmission body to the input portion is cut off.

Images