Separation roller unit and image forming apparatus

Abstract

By unitizing the separation rollers, the number of parts required when mounting them to the image forming apparatus is reduced, and the number of work steps is decreased, improving the work efficiency when replacing the separation rollers. [Solution] The separation roller unit 40, which is detachable from a mounting portion 37 located opposite the paper feed roller 33, comprises a separation roller 41 positioned to join with the paper feed roller 33, a unit body 50 that holds the separation roller 41 and is mounted on the mounting portion 37, and a biasing member 72 provided on the unit body 50 that biases the separation roller 41, which joins with the paper feed roller 33, toward the paper feed roller 33. The unit body 50 has a projection 53 that engages with an insertion groove 39 formed in the mounting portion 37, and when the projection 53 is inserted to the innermost end 39a of the insertion groove 39, the unit body 50 changes its posture due to the biasing force of the biasing member 72, and a part of the projection 53 is locked into a locking portion 39b formed in the insertion groove 39.

Description

Technical Field

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

Background Art

[0002] An image forming apparatus such as an MFP (Multifunction Peripheral) includes a sheet feeding unit that feeds sheets such as printing paper one by one. The sheet feeding unit has a pickup roller, a sheet feeding roller, and a separating roller. The pickup roller rotates in a predetermined direction while being joined to the uppermost surface of the stacked sheets, thereby feeding the sheets toward the sheet feeding roller and the separating roller. The sheet feeding roller and the separating roller are joined to each other to form a nip portion. The sheet fed by the pickup roller passes through the nip portion.

[0003] The sheet feeding roller is rotationally driven by a motor. Therefore, the sheet feeding roller feeds the first sheet fed from the pickup roller toward the downstream conveyance path.

[0004] On the other hand, the separating roller is not rotationally driven. That is, the separating roller is driven to rotate passively by the torque when a torque of a predetermined value or more acts thereon. When a plurality of sheets are fed by the pickup roller, the separating roller joins to the second and subsequent sheets. In this case, the torque acting on the separating roller becomes less than the predetermined value, and the separating roller does not rotate. Therefore, the separating roller can separate the second and subsequent sheets.

[0005] In the separating roller as described above, wear on the roller surface tends to progress. Therefore, conventionally, a technique has been proposed in which the separating roller is unitized so that the separating roller can be replaced relatively easily (for example, Patent Document 1). This conventional technique enables a holder member in which the separating roller is unitized to be attached to a conveyance guide.

[0006] However, the conventional technology described above has the drawback of having a large number of parts, as it requires attaching a stopper member to secure the holder member after it has been mounted on the transport guide. Furthermore, when replacing the separation roller, it is necessary to first remove the stopper member, then remove the old holder member, then install the new holder member, and then reattach the stopper member. Therefore, the conventional technology also has the drawback of having many steps involved in replacing the separation roller, resulting in poor workability. [Prior art documents] [Patent Documents]

[0007] [Patent Document 1] Japanese Patent Publication No. 2016-204150 [Overview of the Initiative] [Problems that the invention aims to solve]

[0008] This invention was made to solve the above problems. Specifically, the present invention aims to provide a separation roller unit and an image forming apparatus that reduce the number of parts when the separation roller is unitized and mounted on the image forming apparatus, reduce the number of work hours, and improve the workability when replacing the separation roller. [Means for solving the problem]

[0009] To achieve the above objective, the invention according to claim 1 is a separation roller unit that is detachable from a mounting portion provided at a position opposite to a paper feed roller, comprising: a separation roller arranged to be joined to the paper feed roller; a unit body that holds the separation roller and is mounted on the mounting portion; and a biasing member provided on the unit body that biases the separation roller, which is joined to the paper feed roller, toward the paper feed roller, wherein the unit body has a projection that engages with an insertion groove formed in the mounting portion, and when the projection is inserted to the inner end of the insertion groove, the unit body changes its posture due to the biasing force of the biasing member, and a part of the projection is locked into a locking portion formed in the insertion groove.

[0010] The invention according to claim 2 is characterized in that, in the separation roller unit of claim 1, when the projection is inserted to the innermost end of the insertion groove, the biasing member biases the unit body in a direction that separates it from the paper feed roller, thereby changing the orientation of the unit body.

[0011] The invention according to claim 3 is a separation roller unit according to claim 1, further comprising a holder that pivotally supports both ends of the separation roller, wherein the unit body pivotally supports the holder at a position different from the position in which the holder pivotally supports the separation roller.

[0012] The invention according to claim 4 is a separation roller unit according to claim 3, characterized in that the holder is equipped with a torque limiter that rotates the separation roller when the torque acting on the separation roller exceeds a predetermined value, and does not rotate the separation roller when the torque acting on the separation roller is less than the predetermined value.

[0013] The invention according to claim 5 is a separation roller unit according to claim 1, characterized in that the unit body has a first guide portion that guides the sheet fed by the paper feed roller in a predetermined direction when mounted on the mounting portion.

[0014] The invention according to claim 6 is a separation roller unit according to claim 5, wherein the unit body has a back side of the first guide portion facing the sheet transport path, and a second guide portion on the back side of the first guide portion that guides the sheet being transported along the transport path.

[0015] The invention according to claim 7 is a separation roller unit according to claim 1, characterized in that the insertion angle of the projection with respect to the insertion groove is inclined at a predetermined angle with respect to the paper feeding direction by the paper feeding roller.

[0016] The invention according to claim 8 is a separation roller unit according to claim 1, characterized in that when the unit body is mounted on the mounting portion, the paper feeding direction by the paper feed roller and the separation roller is an oblique upward direction having a first angle with respect to the horizontal direction, and when the unit body is mounted on the mounting portion, the insertion direction of the projection into the insertion groove is an oblique downward direction having a second angle with respect to the horizontal direction, and the second angle is greater than the first angle.

[0017] The invention according to claim 9 is a separation roller unit according to claim 1, characterized in that the projection protrudes outward from the left and right side walls of the unit body.

[0018] The invention according to claim 10 is a separation roller unit according to claim 1, wherein the projection is formed as a flat plate-shaped projection that protrudes outward from the left and right side walls of the unit body, the tip of the flat plate-shaped projection is inserted to the inner end of the insertion groove, and the rear end of the flat plate-shaped projection is locked into the locking portion.

[0019] The invention according to claim 11 is the separation roller unit according to claim 1, wherein the protrusion has a first protrusion protruding outside the left and right side walls of the unit body, and a second protrusion protruding outside the left and right side walls of the unit body at a position separated from the first protrusion by a predetermined distance, and the first protrusion is inserted to the inner end of the insertion groove, and the second protrusion is locked to the locking portion.

[0020] The invention according to claim 12 is the separation roller unit according to claim 1, wherein the unit body is removable from the mounting portion by releasing the locking state between a part of the protrusion and the locking portion against the biasing force of the biasing member.

[0021] The invention according to claim 13 is an image forming apparatus, comprising the separation roller unit according to any one of claims 1 to 12.

[0022] The invention according to claim 14 is the image forming apparatus according to claim 13, further comprising a device body, a manual feed tray, and a door member that is openable and closable with respect to the device body, and the separation roller unit is detachable from the mounting portion when the door member is open.

Advantages of the Invention

[0023] According to the present invention, when the protrusion of the unit body is inserted to the inner end of the insertion groove provided in the mounting portion, the unit body changes its posture by the biasing force of the biasing member, and a part of the protrusion is locked to the locking portion formed in the insertion groove. Therefore, the separation roller unit of the present invention can reduce the number of parts when mounted on an image forming apparatus, and can reduce the working hours when replacing the separation roller and improve the working efficiency.

Brief Description of the Drawings

[0024] [Figure 1] It is a diagram illustrating the external configuration of an image forming apparatus. [Figure 2]It is a diagram showing the internal structure of the printer unit. [Figure 3] It is a diagram showing an enlarged view of a paper feeding unit that feeds a sheet from a manual feed tray. [Figure 4] It is a perspective view showing a separation roller unit. [Figure 5] It is a side view and a cross-sectional view of the separation roller unit. [Figure 6] It is a diagram showing a state in which a door member of an image forming apparatus is opened. [Figure 7] It is a diagram of the mounting portion viewed from the lateral direction. [Figure 8] It is a diagram showing a process in which a separation roller unit is mounted on a mounting portion. [Figure 9] It is a diagram showing a process in which a separation roller unit is mounted on a mounting portion. [Figure 10] It is a diagram showing a mounting direction when mounting a separation roller unit on a mounting portion. [Figure 11] It is a diagram showing the internal structure of an image forming apparatus on which a separation roller unit is mounted. [Figure 12] It is a diagram showing a modification example of a protrusion.

Embodiments for Carrying Out the Invention

[0025] Hereinafter, preferred embodiments of the present invention will be described in detail while referring to the drawings. In the embodiments described below, elements common to each other are denoted by the same reference numerals, and redundant descriptions thereof are omitted.

[0026] (One Embodiment of the Invention) FIG. 1 is a diagram illustrating an external configuration of an image forming apparatus 1 according to an embodiment of the present invention. This image forming apparatus 1 is configured as, for example, an MFP and has a printing function, a scanning function, and a copying function.

[0027] The image forming apparatus 1 has a printer unit 2 in the center of the main body. The printer unit 2 has a paper feed cassette 3a at its bottom. The paper feed cassette 3a has a paper feed tray 10 (see Figure 2) inside, and a stack of sheets 8 such as printing paper can be placed in the paper feed tray 10 by pulling it out towards the front of the main body. The printer unit 2 also has a manual feed tray 3b on the side of the main body that can be opened and closed by rotating around a horizontal axis. The manual feed tray 3b can be opened laterally from the main body to allow sheets 8 such as printing paper to be placed on it. The manual feed tray 3b is provided on a door member 7 provided on the side of the main body. The door member 7 can be opened and closed by rotating around a vertical axis on the side of the main body, allowing the inside of the main body to be opened.

[0028] The printer unit 2 performs electrophotographic image formation on the sheet 8 fed from the paper feed tray 10 or the manual feed tray 3b. Specifically, the printer unit 2 transfers a toner image based on the image data to be printed onto the sheet 8, fixes the toner image onto the sheet 8, and discharges it into the output tray 4 located at the top of the printer unit 2.

[0029] The image forming apparatus 1 includes a scanner unit 5 and an operation panel 6 located above the printer unit 2. The scanner unit 5 optically reads the image of the original document set by the user and generates image data. For example, if the job specified by the user is a copy job, the scanner unit 5 reads the original document and generates image data, and the printer unit 2 performs image formation on the sheet 8 based on that image data. The operation panel 6 serves as the user interface for when the user operates the image forming apparatus 1. This operation panel 6 displays various screens to the user and accepts user operations.

[0030] Figure 2 shows the internal structure of the printer unit 2. The printer unit 2 includes a transport mechanism 2a for transporting the sheet 8 and an image forming mechanism 2b for forming an image on the sheet 8. The operation of the transport mechanism 2a and the image forming mechanism 2b is controlled by a controller (not shown).

[0031] The transport mechanism 2a is a mechanism that feeds one sheet 8 from the top of a stack of sheets 8 set in the paper feed tray 10 or manual feed tray 3b, and transports that sheet 8 along the transport path 11 shown by the dashed line in the figure in the direction of arrow F1.

[0032] As a mechanism for feeding paper from the paper tray 10, the transport mechanism 2a includes a pickup roller 12 and a roller pair 13. The pickup roller 12 feeds the sheets 8 contained in the paper tray 10 toward the roller pair 13. The roller pair 13 includes a feed roller and a separation roller, which separate the first sheet 8 from the second and subsequent sheets 8, and feeds only the first sheet 8 into the transport path 11.

[0033] As a mechanism for feeding paper from the manual feed tray 3b, the transport mechanism 2a includes a paper feeding section 30. The paper feeding section 30, as described above, is equipped with a pickup roller and a pair of rollers, and feeds only the topmost sheet 8 of the sheets 8 placed on the manual feed tray 3b into the transport path 11. The detailed configuration of the paper feeding section 30 will be described later.

[0034] The transport path 11 for the sheet 8 is equipped with a timing roller 14, a secondary transfer roller 15, a fuser unit 16, and a paper discharge roller 17. The sheet 8 fed into the transport path 11 from the paper feed tray 10 or manual feed tray 3b stops briefly at the position of the timing roller 14. Then, in conjunction with the timing at which the toner image, which has been primary transferred to the intermediate transfer belt 20 by the image forming mechanism 2b, reaches the position of the secondary transfer roller 15, the timing roller 14 is driven to rotate, and the sheet 8 is transported toward the secondary transfer roller 15. As a result, when the sheet 8 passes the position of the secondary transfer roller 15, the toner image that has been primary transferred to the intermediate transfer belt 20 is secondary transferred to the surface of the sheet 8. The sheet 8 with the transferred toner image is then subjected to heat treatment and pressure treatment as it passes through the fuser unit 16, and the toner image is fixed to its surface. The sheet 8 with the fixed toner image is then discharged to the paper discharge tray 4 by the paper discharge roller 17.

[0035] The image forming mechanism 2b has an intermediate transfer belt 20 stretched between a drive roller 20a and a driven roller 20b. The drive roller 20a is positioned opposite the secondary transfer roller 15 across the sheet transport path 11 of the sheet 8 and is rotationally driven in a predetermined direction (counterclockwise) by a motor (not shown). The driven roller 20b is positioned at approximately the same height as the drive roller 20a but at a distance from the drive roller 20a. The intermediate transfer belt 20 is configured as an endless belt, and as the drive roller 20a is rotationally driven in the predetermined direction, the intermediate transfer belt 20 moves in a circular motion in the direction of arrow F2 in the figure.

[0036] The image forming mechanism 2b has a plurality of image forming units 21Y, 21M, 21C, and 21K arranged at predetermined intervals below the intermediate transfer belt 20. Each of the image forming units 21Y, 21M, 21C, and 21K handles a different color of toner. Image forming unit 21Y forms a yellow (Y) toner image. Image forming unit 21M forms a magenta (M) toner image. Image forming unit 21C forms a cyan (C) toner image. Image forming unit 21K forms a black (K) toner image. However, the specific configuration and operation of these image forming units 21Y, 21M, 21C, and 21K are common to each other. Therefore, each of the image forming units 21Y, 21M, 21C, and 21K will be collectively referred to as image forming unit 21, and their specific configuration and operation will be described accordingly.

[0037] The image forming unit 21 comprises a photoreceptor 22, a charger 23, an exposure unit 24, a developer unit 25, a primary transfer roller 27, and a cleaner 26. The photoreceptor 22 is configured as a cylindrical drum and is rotationally driven in a predetermined direction. The charger 23, exposure unit 24, developer unit 25, primary transfer roller 27, and cleaner 26 are arranged around the photoreceptor 22. The primary transfer roller 27 is positioned on the opposite side of the photoreceptor 22, with the intermediate transfer belt 20 in between.

[0038] The charger 23 charges the photosensitive layer on the surface of the photoreceptor 22 to a predetermined charge. The exposure unit 24 has a light source, such as a semiconductor laser or a light-emitting diode, and exposes the photosensitive layer, which has been charged to a predetermined charge, based on the image data to be drawn. As a result, an electrostatic latent image is formed on the surface of the photoreceptor 22. The developer unit 25 is filled with a developer containing toner, and develops the electrostatic latent image with toner by applying the developer to the surface of the photoreceptor 22. As a result, a toner image is formed on the surface of the photoreceptor 22.

[0039] The toner image formed on the surface of the photoreceptor 22 is first transferred to the intermediate transfer belt 20 by the transfer voltage applied from the primary transfer roller 27 when the photoreceptor passes a position opposite the primary transfer roller 27. This operation is performed sequentially in each color image forming unit 21, so that the toner images of Y, M, C, and K are sequentially superimposed and transferred onto the intermediate transfer belt 20, forming a color image. This color image is secondarily transferred to the sheet 8 when the sheet 8 passes through the nip between the intermediate transfer belt 20 and the secondary transfer roller 15. Any toner remaining on the surface of the photoreceptor 22 that was not first transferred to the intermediate transfer belt 20 is removed from the surface of the photoreceptor 22 by the cleaner 26.

[0040] Figure 3 is an enlarged view of the paper feeding unit 30 that feeds sheets 8 from the manual feed tray 3b. The paper feeding unit 30 includes a pickup roller 31, a lifting tray 32, a transport guide 35, a paper feed roller 33, and a separation roller unit 40. The lifting tray 32 is positioned at the front end of the manual feed tray 3b and holds the front end of the sheet 8 placed on the manual feed tray 3b. The front end of the lifting tray 32 is positioned below the pickup roller 31 and can be raised and lowered. For example, when the paper feeding operation is performed by the paper feeding unit 30, the front end of the lifting tray 32 can be raised, pressing the top surface of the sheet 8 placed on the tray against the pickup roller 31.

[0041] The pickup roller 31 contacts the upper surface of the sheet 8 placed on the lifting tray 32 and rotates in a predetermined direction, thereby feeding the sheet 8 toward the paper feed roller 33. The transport guide 35 is positioned between the pickup roller 31 and the paper feed roller 33 and adjusts the leading edge position of the sheet 8 supplied to the paper feed roller 33.

[0042] The paper feed roller 33 is rotationally driven by a drive source such as a motor (not shown). The rotation axis 34 of the paper feed roller 33 is held rotatably at a predetermined position in the paper feeding section 30. Therefore, the paper feed roller 33 rotates at a fixed position in the paper feeding section 30 and feeds the sheets 8 sent out from the pickup roller 31 toward the transport path 11.

[0043] The separation roller unit 40 holds the separation roller 41. The separation roller unit 40 is detachable from the paper feed unit 30, and the unit can be replaced if the surface of the separation roller 41 becomes worn. When the separation roller unit 40 is attached to the paper feed unit 30, it joins the separation roller 41 to the paper feed roller 33, as shown in Figure 3. The separation roller unit 40 biases the separation roller 41 to press against the paper feed roller 33 with a predetermined pressing force. This forms a nip portion between the paper feed roller 33 and the separation roller 41, and a roller pair of the paper feed roller 33 and the separation roller 41 is formed, similar to the roller pair 13.

[0044] Therefore, when the separation roller unit 40 is attached to the paper feeding section 30, the roller pair consisting of the paper feeding roller 33 and the separation roller 41 has the function of separating the first sheet 8 from the second and subsequent sheets 8. For example, when multiple sheets 8 are fed toward the paper feeding roller 33 by the pickup roller 31, these multiple sheets 8 enter the nip section formed by the paper feeding roller 33 and the separation roller 41. At that time, the paper feeding roller 33 joins with the first sheet 8 on the top surface and feeds the first sheet 8 toward the transport path 11. On the other hand, the separation roller 41 joins with the second and subsequent sheets 8, preventing the second and subsequent sheets 8 from moving together with the first sheet 8 and separating the second and subsequent sheets 8.

[0045] Figure 4 is a perspective view showing the separation roller unit 40. Figure 5 is a side view and a cross-sectional view of the separation roller unit 40. Figure 5(a) shows a side view. Figure 5(b) shows a cross-sectional view. The separation roller unit 40 includes a separation roller 41, a unit body 50, a holder 60, and a biasing member 72. The separation roller 41 has both ends of its shaft portion 42 held by the holder 60. The unit body 50 pivotably supports the holder 60 that holds the separation roller 41. The biasing member 72 is made up of, for example, a coil spring. The biasing member 72 is positioned between the holder 60 and the unit body 50 and applies a biasing force to the separation roller 41.

[0046] A torque limiter 43 is attached to the shaft 42 of the separation roller 41. The torque limiter 43 applies a load when the separation roller 41 rotates around the shaft 42. The torque limiter 43 allows the separation roller 41 to rotate if the torque acting on the separation roller 41 is greater than or equal to a predetermined value. Conversely, the torque limiter 43 does not allow the separation roller 41 to rotate if the torque acting on the separation roller 41 is less than a predetermined value. Due to the function of this torque limiter 43, the separation roller 41 separates the second and subsequent sheets 8 from the first sheet 8.

[0047] The holder 60 has a holding portion 61 that houses the separation roller 41 inside and holds both ends of the shaft portion 42, a locking portion 62 provided at the lower part of the holding portion 61, and a base portion 63 provided at the upper part of the holding portion 61. The surface of the base portion 63 is inclined diagonally upward and guides the sheet 8 fed by the paper feed roller 33 toward the transport path 11. The shaft portion 71 is attached to the back side of the base portion 63. The shaft portion 71 connects the unit body 50 and the holder 60 and pivotally supports the holder 60 relative to the unit body 50. The holder 60 can change its orientation relative to the unit body 50 by pivoting around the axis 71a of the shaft portion 71. The locking portion 62 locks one end of the biasing member 72.

[0048] The unit body 50 is positioned on the rear side of the holder 60 and has a housing 51 that holds the holder 60. Side walls 52 are provided on both the left and right sides of the housing 51 at predetermined intervals. The side walls 52 are separated from the holding portion 61 of the holder 60 by a predetermined distance and do not come into contact with the holding portion 61 of the holder 60. In addition, a shaft portion 71 is mounted at a predetermined position on the side wall 52. The side wall 52 supports the holder 60 by its shaft portion 71. The shaft portion 71 supports the holder 60 at a position on the side wall 52 that is different from the position where the holder 60 pivotally supports the separation roller 41. As a result, the unit body 50 pivotally supports the holder 60 via the shaft portion 71 so that it can swing.

[0049] As shown in Figure 5(b), the unit body 50 has a locking portion 54 located below the holder 60. The locking portion 54 locks the other end of the biasing member 72. In other words, the biasing member 72 is provided on the unit body 50 and applies a biasing force between the unit body 50 and the holder 60. For example, when the separation roller unit 40 is mounted on the paper feed section 30, the biasing member 72 biases the separation roller 41 toward the paper feed roller 33 with a predetermined pressing force.

[0050] A projection 53 is provided on the side wall 52 of the unit body 50. The projection 53 protrudes perpendicularly outward from the side wall 52. For example, as shown in Figure 4, the projection 53 is formed as a flat plate-shaped projection that protrudes outward from the side wall 52. This projection 53 is inclined diagonally, with the tip 53a being lower than the rear end 53b.

[0051] Figure 6 shows the image forming apparatus 1 with the door member 7 open. As shown in Figure 6, the paper feeding unit 30 is installed inside the door member 7. Therefore, when the door member 7 is opened, the paper feeding unit 30 moves to the outside of the image forming apparatus 1 together with the door member 7. The paper feeding unit 30 is provided with a mounting portion 37 for attaching the separation roller unit 40 at a position opposite the paper feeding roller 33. This mounting portion 37 becomes accessible from the outside when the door member 7 is opened. Therefore, the separation roller unit 40 is detachable from the mounting portion 37 when the door member 7 is open.

[0052] Figure 7 is a side view of the mounting section 37. The mounting section 37 has walls 38 on both the left and right sides of the space that accommodates the separation roller unit 40. The separation roller unit 40 is inserted and mounted between these walls 38. Insertion grooves 39 are formed in the walls 38 of the mounting section 37. These insertion grooves 39 are grooves that guide the insertion direction of the projections 53 of the separation roller unit 40. Note that the insertion grooves 39 may also be provided as slits formed in the walls 38, as shown in Figure 7.

[0053] The insertion groove 39 slopes downward from the opening of the mounting portion 37 towards the back of the mounting portion 37. The insertion groove 39 is wider near the opening of the mounting portion 37 and gradually narrows towards the back of the mounting portion 37. The innermost end 39a of the insertion groove 39 is formed to engage with the tip 53a of the projection 53. Therefore, the separation roller unit 40 is inserted and mounted onto the mounting portion 37 from an obliquely upward position towards an obliquely downward position. At this time, the projection 53 enters the insertion groove 39, and the orientation of the unit body 50 is restricted by the gradually narrowing groove width as it is mounted onto the mounting portion 37.

[0054] Furthermore, the insertion groove 39 has a locking portion 39b at a predetermined distance from the inner end portion 39a. For example, the locking portion 39b is formed by providing a step at the lower edge of the insertion groove 39. The distance between the locking portion 39b and the inner end portion 39a is equal to the length of the projection 53. Therefore, when the tip 53a of the projection 53 is inserted to the inner end portion 39a of the insertion groove 39, the locking portion 39b can be locked to the rear end 53b of the projection 53.

[0055] Figures 8 and 9 show the process of mounting the separation roller unit 40 to the mounting section 37. First, as shown in Figure 8(a), the projection 53 enters the insertion groove 39 and the separation roller unit 40 is mounted to the mounting section 37, causing the separation roller 41 to come into contact with the paper feed roller 33. Furthermore, as the unit body 50 of the separation roller unit 40 is pushed towards the back of the mounting section 37, as shown in Figure 8(b), the unit body 50 moves towards the back of the mounting section 37 with the separation roller 41 in contact with the paper feed roller 33. At this time, the holder 60 changes its orientation relative to the unit body 50, and the biasing member 72 is compressed and deformed.

[0056] Furthermore, as the unit body 50 of the separation roller unit 40 is pushed toward the back of the mounting portion 37, the tip 53a of the projection 53 engages with the inner end 39a of the insertion groove 39, as shown in Figure 9(a). At this time, the amount of change in the posture of the holder 60 relative to the unit body 50 increases, and the amount of compression of the biasing member 72 also increases. In other words, a relatively large amount of elastic energy is accumulated in the biasing member 72.

[0057] In the state shown in Figure 9(a), when the force pushing the unit body 50 is released, the biasing member 72 biases the unit body 50 in a direction that separates it from the paper feed roller 33. The unit body 50 changes its orientation due to the biasing force of the biasing member 72. That is, the unit body 50 changes its orientation in the direction indicated by arrow F3 in Figure 9(b). Due to this change in orientation, the rear end 53b of the projection 53 becomes engaged with the locking portion 39b of the insertion groove 39. In other words, the separation roller unit 40 is mounted so that it does not detach from the mounting portion 37.

[0058] The biasing member 72 fixes the separation roller unit 40 to the mounting part 37 by its biasing force. Therefore, when attaching the separation roller unit 40 to the mounting part 37, there is no need to attach another stopper member or the like. Consequently, the number of parts required when attaching the separation roller unit 40 to the mounting part 37 is reduced, thereby reducing the user's workload.

[0059] Furthermore, when removing the separation roller unit 40 from the mounting section 37, the procedure is the reverse of the above. At this time, since the separation roller unit 40 does not have a stopper member or the like attached, the user can easily and efficiently pull out and remove the separation roller unit 40 from the mounting section 37. Therefore, this separation roller unit 40 can improve the workability when replacing the separation roller 41.

[0060] When the separation roller unit 40 is mounted on the mounting section 37, the biasing member 72 biases the separation roller 41 toward the paper feed roller 33 with a predetermined pressing force. Therefore, when multiple sheets 8 are fed out by the pickup roller 31, the separation roller 41 can separate the second and subsequent sheets 8 from the first sheet 8.

[0061] Figure 10 shows the mounting direction when the separation roller unit 40 is mounted on the mounting section 37. When the paper feeding operation is performed by the paper feeding section 30 with the separation roller unit 40 mounted on the mounting section 37, the sheet 8 is fed in the paper feeding direction indicated by arrow A1 in Figure 10. This paper feeding direction is perpendicular to the line connecting the centers of the paper feeding roller 33 and the separation roller 41, and is diagonally upward. Specifically, the paper feeding direction indicated by arrow A1 has a first angle θ1 with respect to the horizontal direction. In contrast, the insertion angle when mounting the separation roller unit 40 to the mounting section 37 is defined by the insertion groove 39. That is, the separation roller unit 40 is inserted into the insertion groove 39 in the insertion direction indicated by arrow A2 in Figure 10. This insertion direction is diagonally downward. Specifically, the insertion direction indicated by arrow A2 has a second angle θ2 with respect to the horizontal direction.

[0062] As shown in Figure 10, the second angle θ2 is larger than the first angle θ1. Therefore, the insertion angle of the projection 53 with respect to the insertion groove 39 is inclined at a predetermined angle with respect to the paper feeding direction by the paper feed roller 33. Consequently, the separation roller 41 can always come into contact with the paper feed roller 33 during the process in which the projection 53 of the separation roller unit 40 is inserted to the innermost end 39a of the insertion groove 39. As a result, during the insertion process of the separation roller unit 40, the holder 60 can be changed in position relative to the unit body 50, and elastic energy can be accumulated in the biasing member 72. Then, when the projection 53 is inserted to the innermost end 39a of the insertion groove 39, a portion of that elastic energy is released, causing the unit body 50 to change in position. This causes the rear end 53b of the projection 53 to be locked into the locking portion 39b of the insertion groove 39.

[0063] Figure 11 shows the internal structure of the image forming apparatus 1 with the separation roller unit 40 installed. Figure 11 shows the state in which the separation roller unit 40 is installed in the mounting section 37 and the door member 7 is closed. As shown in Figure 11, the unit body 50 of the separation roller unit 40 has a first guide section 59 on the upper front side of the housing 51. The first guide section 59 guides the sheet 8 fed by the paper feed roller 33 in a predetermined direction. That is, the first guide section 59 is formed as an inclined surface that is tilted diagonally and guides the sheet 8 fed by the paper feed roller 33 toward the transport path 11 formed inside the image forming apparatus 1. Because the separation roller unit 40 has the first guide section 59 formed on the housing 51, it can properly guide the sheet 8 fed by the paper feed roller 33 toward the transport path 11.

[0064] Furthermore, the unit body 50 has its rear surface 55 facing the transport path 11. The unit body 50 has a second guide section 58 on its rear surface 55 that guides the sheets 8 being transported along the transport path 11. The second guide section 58 guides the sheets 8 fed from the paper feed tray 10 so that they are transported along the transport path 11. Because the second guide section 58 is formed on the rear surface 55 of the housing 51 in this way, the sheets 8 fed from the paper feed tray 10 are transported along the transport path 11 by the second guide section 58.

[0065] As described above, the image forming apparatus 1 of this embodiment is equipped with a separation roller unit 40 that can be attached to and detached from a mounting portion 37 provided at a position opposite the paper feed roller 33. This separation roller unit 40 comprises a separation roller 41, a unit body 50, and a biasing member 72. The separation roller 41 is positioned so as to be joined to the paper feed roller 33 when the separation roller unit 40 is mounted on the mounting portion 37. The unit body 50 holds the separation roller 41 and is attached to and detached from the mounting portion 37. The biasing member 72 is provided on the unit body 50 and biases the separation roller 41, which is joined to the paper feed roller 33, toward the paper feed roller 33. The unit body 50 has a projection 53 that engages with an insertion groove 39 formed in the mounting portion 37. When the projection 53 is inserted to the innermost end 39a of the insertion groove 39, the unit body 50 changes its orientation due to the biasing force of the biasing member 72. This change in posture causes the unit body 50 to be configured to engage a portion of the projection 53 with the locking portion 39b formed in the insertion groove 39.

[0066] As described above, when the separation roller unit 40 is mounted on the mounting section 37, it is fixed in a locked state by the locking section 39b due to the change in the orientation of the unit body 50. Therefore, it is possible to fix the separation roller unit 40 to the mounting section 37 without using a stopper member or the like. Consequently, the separation roller unit 40 can reduce the number of parts required to mount and fix it to the image forming apparatus 1, and the amount of work required when replacing it can be reduced.

[0067] (modified version) Preferred embodiments of the present invention have been described above. However, the present invention is not limited to those described in the above embodiments, and various modifications are applicable.

[0068] For example, in the above embodiment, an example was shown in which the projection 53 formed on the side wall 52 of the unit body 50 is a flat plate-shaped projection that is inclined diagonally. However, the projection 53 is not limited to a flat plate-shaped projection. For example, the projection 53 may be composed of a first projection 531 and a second projection 532, as shown in Figure 12. The first projection 531 protrudes to the outside of the left and right side walls 52 of the unit body 50. The second projection 532 protrudes to the outside of the left and right side walls 52 of the unit body 50 at a predetermined distance from the first projection 531. For example, the first projection 531 corresponds to the tip 53a of the projection 53 described in the above embodiment. The second projection 532 corresponds to the rear end 53b of the projection 53 described in the above embodiment. When the separation roller unit 40 is mounted on the mounting part 37, the first projection 531 is inserted to the inner end 39a of the insertion groove 39, and the second projection 532 is locked into the locking part 39b. A separation roller unit 40 having such a configuration provides the same effects as those described in the above embodiment.

[0069] Furthermore, in the above embodiment, a separation roller unit 40 attached to the paper feeding section 30 of the manual feed tray 3b was illustrated as an example. However, the scope to which the above-described separation roller unit 40 can be applied is not limited to the paper feeding section 30 of the manual feed tray 3b. For example, the above-described separation roller unit 40 can also be applied to the paper feeding section that feeds sheets 8 from the paper feed tray 10. For example, the separation roller included in the roller pair 13 may be implemented with the same configuration as the above-described separation roller unit 40. In addition, the above-described separation roller unit 40 may be provided in the paper feeding section that feeds and transports documents to be image scanned one by one in the scanner section 5.

[0070] Furthermore, in the above embodiment, a configuration example was described in which a holder 60 is provided inside the unit body 50, and the holder 60 pivots on both ends of the separation roller 41. However, the separation roller unit 40 may not have a configuration that includes a holder 60. That is, the unit body 50 can pivotally support the separation roller 41, and the biasing force of the biasing member 72 can bias the separation roller 41 toward the paper feed roller 33.

[0071] Furthermore, in the above embodiment, an example was described in which the biasing member 72 is composed of a coil spring. However, the biasing member 72 is not limited to a coil spring. For example, the biasing member 72 may be composed of a torsion spring, a leaf spring, or the like.

[0072] Furthermore, in the above embodiment, an example was described in which the image forming apparatus 1 is configured as an MFP. However, the image forming apparatus 1 is not limited to being configured as an MFP. For example, the image forming apparatus 1 may be a printer equipped only with a printing function. [Explanation of Symbols]

[0073] 1. Image forming apparatus 2 Printer section 7 Door components 11 Conveyor path 30 Paper feed section 33 Paper feed roller 37 Mounting part 39 Insertion groove 39a Back end 39b Locking part 40 Separation Roller Unit 41 Separation roller 43 Torque Limiter 50 Unit Body 52 Side wall 53 Protrusion 53a Tip 53b rear end 58. Section 2 Guide 59. Section 1 Guide 60 holder 72 Biasing member 531 First protrusion 532 Second protrusion

Claims

1. A detachable separation roller unit, which is attached to a mounting part located opposite the paper feed roller, A separation roller is positioned to be joined to the aforementioned paper feed roller, The unit body, which holds the separation roller and is mounted on the mounting portion, A biasing member provided on the unit body, which biases the separation roller, which is joined to the paper feed roller, toward the paper feed roller, Equipped with, The separation roller unit is characterized in that the unit body has a projection that engages with an insertion groove formed in the mounting portion, and when the projection is inserted to the innermost end of the insertion groove, the unit body changes its posture due to the biasing force of the biasing member, and a part of the projection engages with a locking portion formed in the insertion groove.

2. The separation roller unit according to claim 1, characterized in that when the projection is inserted to the inner end of the insertion groove, the biasing member biases the unit body in a direction that separates it from the paper feed roller, thereby changing the orientation of the unit body.

3. Holders that pivotally support both ends of the separation roller, Furthermore, The separation roller unit according to claim 1, characterized in that the unit body pivotally supports the holder at a position different from the position in which the holder pivotally supports the separation roller.

4. The separation roller unit according to claim 3, characterized in that the holder includes a torque limiter that rotates the separation roller when the torque acting on the separation roller exceeds a predetermined value, and does not rotate the separation roller when the torque acting on the separation roller is less than the predetermined value.

5. The separation roller unit according to claim 1, characterized in that the unit body has a first guide portion that guides the sheet fed by the paper feed roller in a predetermined direction when mounted on the mounting portion.

6. The separation roller unit according to claim 5, characterized in that the unit body has a rear side of the first guide portion facing the sheet transport path, and a second guide portion on the rear side of the first guide portion that guides the sheet being transported along the transport path.

7. The separation roller unit according to claim 1, characterized in that the insertion angle of the projection with respect to the insertion groove is inclined at a predetermined angle with respect to the paper feeding direction by the paper feed roller.

8. When the unit body is mounted on the mounting portion, the paper feeding direction by the paper feed roller and the separation roller becomes an upward-slanting direction having a first angle with respect to the horizontal direction. When the unit body is mounted on the mounting portion, the insertion direction of the projection into the insertion groove becomes a diagonally downward direction having a second angle with respect to the horizontal direction. The separation roller unit according to claim 1, characterized in that the second angle is greater than the first angle.

9. The separation roller unit according to claim 1, characterized in that the projections protrude outward from the left and right side walls of the unit body.

10. The separation roller unit according to claim 1, characterized in that the projection is formed as a flat plate-shaped projection that protrudes outward from the left and right side walls of the unit body, the tip of the flat plate-shaped projection is inserted to the inner end of the insertion groove, and the rear end of the flat plate-shaped projection is locked into the locking portion.

11. The separation roller unit according to claim 1, characterized in that the projection has a first projection that protrudes to the outside of the left and right side walls of the unit body and a second projection that protrudes to the outside of the left and right side walls of the unit body at a predetermined distance from the first projection, the first projection is inserted to the inner end of the insertion groove and the second projection engages with the locking portion.

12. The separation roller unit according to claim 1, characterized in that the unit body is removable from the mounting portion by releasing the locking state between a part of the projection and the locking portion against the biasing force of the biasing member.

13. An image forming apparatus characterized by comprising a separation roller unit according to any one of claims 1 to 12.

14. The main body of the device, A door member that has a manual feed tray and can be opened and closed relative to the main body of the device, Furthermore, The image forming apparatus according to claim 13, characterized in that the separation roller unit is detachable from the mounting portion when the door member is open.

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