Image forming device

Abstract

The present invention discloses an image forming device. The image forming device includes an upper guide unit fixed to the image forming device and configured to guide the upper surface of a sheet discharged by a roller pair, a stacking unit arranged at a position recessed from an upper housing unit of the image forming device, and an operating unit including a display unit. The discharged sheets are stacked on the stacking unit. The upper guide unit extends further downstream than the roller pair in the discharge direction. The operating unit and the upper guide unit each have a portion that overlaps with each other. When viewed from the axial direction of the roller pair, the operating unit and the upper guide unit are arranged at a position where a straight line passes through, and the straight line is orthogonal to a plane passing through the roller axis of the roller pair and passes through the clamping portion of the roller pair.

Description

Technical Field

[0001] The present invention relates to an image forming apparatus for forming an image on a sheet. Background Art

[0002] Some image forming devices, such as printers and facsimile machines, are equipped with an operating unit configured to display information to the user or allow the user to operate the device. The operating unit is positioned outside the sheet stacking unit in the image forming device, in the sheet width direction orthogonal to the sheet discharge direction, so that the operating unit does not come into contact with discharged sheets. Furthermore, from the perspectives of the size and design of the image forming device, as well as to prevent damage, it is desirable that the operating unit does not protrude from the side of the device.

[0003] On the other hand, if the size of the operation unit is increased for the purpose of improving usability, such as increasing the amount of information displayed on the operation unit or adopting a touch panel, the operation unit tends to become larger. If a large-sized operation unit is provided so that the operation unit does not protrude from the side of the device, it may be difficult to arrange the operation unit outside the sheet stacking unit. In other words, the operation unit may protrude directly above the sheet stacking unit in the width direction of the sheets.

[0004] Therefore, Japanese Patent No. 06341975 describes a configuration in which an arm unit configured to connect the upper portion of the image forming apparatus and the operating unit is arranged in the image forming apparatus so that the operating unit does not come into contact with the discharged sheets even when the operating unit is arranged above the stacking unit. According to Japanese Patent No. 06341975, the arm unit is rotatable relative to the main body of the apparatus, and by rotating the arm unit, the operating unit can ensure a distance from the sheets to be discharged.

[0005] Japanese Patent No. 06398307 describes a technique in which a rotation trajectory of an operation unit is arranged above a paper discharge trajectory of a discharged sheet. According to Japanese Patent No. 06398307, the operation unit is arranged at a position where the operation unit does not come into contact with the discharged sheet.

[0006] However, according to the methods described in Japanese Patent No. 06341975 and Japanese Patent No. 06398307, the arm unit and the operation unit are located at positions distant from the main body of the apparatus, and therefore, the size of the image forming apparatus will increase. Summary of the Invention

[0007] According to one aspect of the present invention, there is provided an image forming apparatus comprising an image forming unit configured to form an image on a sheet, the image forming apparatus comprising: a roller pair configured to convey a sheet having an image formed thereon and to discharge at least a portion of the sheet to the outside of the image forming apparatus; an upper guide unit fixed to the image forming apparatus and configured to guide an upper surface of the sheet discharged by the roller pair; a stacking unit disposed at a position recessed from an upper housing unit of the image forming apparatus, the discharged sheets being stacked on the stacking unit; and an operating unit comprising a display configured to display information regarding an image forming process. a display unit, the operating unit being attached to the upper housing unit of the image forming device, the operating unit being configured to operate the image forming device, wherein the upper guide unit extends along the discharge direction of the sheet discharged by the roller pair, further downstream than the roller pair in the discharge direction, wherein, when viewed from a vertical direction, the operating unit and the upper guide unit each have a portion overlapping each other, and wherein, when viewed from an axial direction of the roller pair, the operating unit and the upper guide unit are arranged at a position where a straight line passes through, the straight line being orthogonal to a plane passing through the roller axis of the roller pair and passing through a clamping portion of the roller pair.

[0008] Further features of the present invention will become apparent from the following description of exemplary embodiments with reference to the attached drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 is a schematic diagram of an image forming apparatus according to a first exemplary embodiment.

[0010] Figure 2 is a perspective view illustrating the arrangement of an operation unit according to the first exemplary embodiment.

[0011] Figure 3 is a plan view of the image forming apparatus according to the first exemplary embodiment as viewed from a vertical direction.

[0012] Figure 4A and Figure 4B is a side view illustrating the configuration of the operation unit according to the first exemplary embodiment.

[0013] Figure 5 is a cross-sectional view illustrating a configuration of a sheet discharge unit according to the first exemplary embodiment.

[0014] Figure 6 yes Figure 5 , illustrating an area near the operation unit according to the first exemplary embodiment.

[0015] Figure 7A and Figure 7Bis a plan view illustrating an example of arrangement of packaging materials of the image forming apparatus according to the first exemplary embodiment.

[0016] Figure 8A and Figure 8B is a perspective view illustrating a shape of an upper guide unit according to a first exemplary embodiment.

[0017] Figure 9 is a cross-sectional view illustrating a relationship between a sheet discharge direction and the operation unit in a case where the operation unit according to the first exemplary embodiment is in the first position.

[0018] Figure 10 is a cross-sectional view illustrating a relationship between a sheet discharge direction and the operation unit in a case where the operation unit according to the first exemplary embodiment is in the second position.

[0019] Figure 11 is a cross-sectional view illustrating a relationship between states of a guide unit and a detection unit according to the first exemplary embodiment.

[0020] Figure 12 is a cross-sectional view illustrating the relationship between the rotational trajectories of the guide unit and the detection unit according to the first exemplary embodiment.

[0021] Figure 13 is a cross-sectional view illustrating a relationship between a guide unit and sheets stacked on a stacking unit according to the first exemplary embodiment.

[0022] Figure 14 is a perspective view illustrating the shape of an upper guide unit according to a second exemplary embodiment.

[0023] Figure 15 is a plan view of the image forming apparatus according to the second exemplary embodiment as viewed from a vertical direction.

[0024] Figure 16 is a perspective view illustrating the shape of an upper guide unit according to a third exemplary embodiment.

[0025] Figure 17 is a plan view of the image forming apparatus according to the third exemplary embodiment as viewed from a vertical direction. DETAILED DESCRIPTION

[0026] As an example of the configuration of an image forming apparatus configured to form an image on a sheet according to the first exemplary embodiment of the present invention, an exemplary embodiment in which the image forming apparatus is applied to an electrophotographic laser beam printer will be specifically described. As an order of explanation, the overall configuration of the image forming apparatus according to this exemplary embodiment will be described first, and then the configuration of a sheet discharge unit of the image forming apparatus according to this exemplary embodiment will be described.

[0027] Figure 1 is a cross-sectional view illustrating a configuration in a case where the image forming apparatus is applied to an electrophotographic laser beam printer having a double-sided image forming function, as an example of the image forming apparatus according to the present exemplary embodiment. Figure 2 and Figure 3 is a schematic diagram illustrating the arrangement of the operation unit 20 according to the first exemplary embodiment, Figure 2 is a perspective view, and Figure 3 is viewed from the vertical direction A Figure 2 . Note that, unless otherwise specified, the dimensions, materials, shapes, relative arrangements, and the like of the components described in this exemplary embodiment are not intended to limit the scope of the present invention to only these. Furthermore, the image forming apparatus according to this exemplary embodiment is not limited to a laser beam printer and can be applied to other image forming apparatuses such as copiers and facsimile machines.

[0028] Roughly speaking, Figure 1 The image forming apparatus 101 illustrated in FIG. 1 includes a sheet feeding unit, an image forming unit, a fixing unit, a paper ejection reversing unit, and a duplex conveying unit. The image forming apparatus 101 includes a process cartridge 1 detachably attached to a main body of the image forming apparatus 101. The process cartridge 1 includes a photosensitive drum 2 and process units such as a developing unit (not shown) and a charging roller.

[0029] The scanner unit 3 is arranged vertically above the process cartridge 1 and exposes the photosensitive drum 2 based on an image signal. The photosensitive drum 2 is charged to a predetermined negative potential by a charging roller (not shown) and then an electrostatic latent image is formed by the scanner unit 3.

[0030] The electrostatic latent image is reversely developed by a developing unit (not shown) in the process cartridge 1 , and negative toner is caused to adhere to form a toner image.

[0031] The sheet feeding unit includes a feed roller 4 mounted on the image forming apparatus 101 and a feed cassette 5 for storing sheets. The feed cassette 5 is detachably attached to the main body of the image forming apparatus 101. Sheets S stored in the feed cassette 5 are fed individually from the feed cassette 5 one by one by the feed roller 4, which is rotated by the power of a paper feeding drive unit (not shown). The fed sheets S are conveyed by a conveying roller pair 6 to a registration roller pair 7, subjected to skew correction by the registration roller pair 7, and then conveyed to the transfer unit.

[0032] The transfer unit is configured to apply a positive bias voltage by a bias applying unit (not shown) to the transfer roller 8. Thereby, the toner image is transferred as an unfixed image to the sheet S conveyed to the transfer unit.

[0033] The sheet S to which the toner image has been transferred is conveyed to a fixing device 9 provided in the transfer unit on the downstream side in the conveying direction of the sheet S. The fixing device 9 fixes the toner image transferred to the sheet S and includes a heating roller 10 heated by a heater (not shown) as a heating unit and a pressure roller 11 as a pressure member that rotates while being pressed against the heating roller 10. The fixing nip formed by the heating roller 10 and the pressure roller 11 pinches and conveys the sheet S, and heat and pressure are applied to the toner image, thereby fixing the toner image to the surface of the sheet S.

[0034] The sheet S on which the toner image is fixed, that is, the sheet S on which the image is formed is conveyed from the fixing device 9 to the paper discharge reversing unit. The paper discharge reversing unit has a triple roller including a driving roller 13, a paper discharge roller 14 and a reversing roller 15, and the paper discharge roller 14 and the reversing roller 15 are driven rollers. The paper discharge reversing unit also has a double-sided baffle 12. The driving roller 13 can receive a drive from a driving source (not shown) and rotate, and each of the paper discharge roller 14 and the reversing roller 15 as driven rollers contacts the driving roller 13 to form a holding portion and forms a roller pair when the driving roller 13 rotates, in which each of the paper discharge roller 14 and the reversing roller 15 rotates in a driven manner.

[0035] Among the roller pairs, the roller pair formed by the driving roller 13 and the paper discharge roller 14 is a discharge roller pair configured to discharge the sheet S to the stacking unit 16. Figure 2 As shown, the stacking unit 16 is provided at a position recessed from the upper housing unit 19 and has a stacking surface 31 on which discharged sheets are stacked. The stacking surface 31 has an inclined surface with the upstream side in the discharge direction of the sheets S being most recessed from the upper surface and gradually becoming shallower toward the downstream side. Furthermore, the roller pair formed by the drive roller 13 and the reverse roller 15 is a reverse roller pair configured to discharge a portion of the sheet S to the outside of the image forming apparatus 101 and then convey the sheet S to the interior of the image forming apparatus 101. In this exemplary embodiment, the upper housing unit 19 forms the upper surface cover of the image forming apparatus 101.

[0036] In progress Figure 5 In the case of a single-sided image forming operation (single-sided printing), the double-sided flapper 12 stands by at a position indicated by a solid line so that the sheet S is guided to the discharge roller pair formed by the drive roller 13 and the discharge roller 14.

[0037] Then, the conveyed sheet S is discharged by the driving roller 13 and the paper discharge roller 14 onto the stacking unit 16 , where the discharged sheet S is stacked outside the image forming apparatus 101 .

[0038] When performing a double-sided image forming operation (duplex printing), the double-sided flapper 12 stands by at the position indicated by the dotted line, guiding the sheet S to the reverse roller pair formed by the drive roller 13 and the reverse roller 15. The sheet S is then conveyed to the reverse roller pair by the fixing device 9. When the trailing edge of the sheet S reaches a predetermined position, the drive roller 13 is reversely rotated by a rotation direction switching unit (not shown). At this point, when the trailing edge of the sheet S reaches the predetermined position, a portion of the sheet S is ejected outside the image forming apparatus 101.

[0039] Due to the reverse rotation of the drive roller 13, the sheet S passes through the duplex conveying roller pair 17 and the re-feeding roller pair 18 in a manner such that the end portion on the upstream side in the discharge direction passes first, and is re-conveyed in an inverted state relative to the registration roller pair 7. Then, similar to the case of single-sided printing, the second side of the sheet S is skew-corrected by the registration roller pair 7, transferred by the transfer roller 8, and fixed by the fixing device 9, and the sheet S is discharged to the stacking unit 16 by the drive roller 13 and the paper discharge roller 14 to complete the double-sided printing.

[0040] Next, refer to Figures 2 to 14 The sheet discharge unit according to this exemplary embodiment will be described. In the following description, illustration of fastening members such as screws will be omitted. An operation unit 20 configured to receive operations of the image forming apparatus 101 is disposed on an upper housing unit 19, which is part of the housing surface of the image forming apparatus 101, and includes a display unit 22 configured to display information regarding the image forming process (e.g., the number of sheets during printing, the remaining amount of developer, etc.).

[0041] like Figure 3 As shown in FIG. 1 , the operation unit 20 is arranged to overlap the stacking unit 16 when viewed from the vertical direction. The operation unit 20 is arranged not to protrude outward from the side surface 33 of the image forming apparatus 101, that is, to be arranged inside the side surface 33. Figure 1 The roller pair is shown on one side of the discharge direction of the sheet S with respect to the center of the image forming apparatus 101. When viewed from the vertical direction, the operation unit 20 also overlaps with an upper guide unit to be described below.

[0042] Figure 4A and Figure 4B is a schematic diagram illustrating the configuration of the operation unit, and is viewed from direction B Figure 2. The operation unit 20 is supported by a holding unit 21 located on the upper housing unit 19. The operation unit 20 is configured to be rotatable around a rotation center portion 23 relative to the holding unit 21. The holding unit 21 is installed within the width of the upper housing unit 19 with respect to the width direction of the sheet S intersecting with the conveying direction of the sheet S, does not protrude toward the stacking unit 16, and does not overlap with an upper guide unit to be described below when viewed from a vertical direction.

[0043] When the operating unit 20 is attached to the upper housing unit 19, the provision of the rotation center portion 23 enables the operating unit 20 to be in a first position in which the operating unit 20 is positioned as shown in FIG. Figure 4A The operating unit 20 is shown to be arranged substantially parallel to the upper housing unit 19. In addition, the operating unit 20 can be in a second position, in which the operating unit 20 is positioned substantially parallel to the upper housing unit 19. Figure 4B As shown, the operation unit 20 is rotated to the maximum angle at which it can be rotated relative to the upper housing unit 19. By rotating the operation unit 20 in this manner, the operation unit 20 can be easily seen when the user operates the image forming apparatus 101. In addition, the operation unit 20 can be fixed not only in the first position and the second position but also at an angle between these positions, and the user can rotate the operation unit 20 to an angle at which the operation unit 20 is easy to use.

[0044] According to the configuration of this exemplary embodiment, the display unit 22 includes a touch sensor, and the user touches the touch sensor to operate the image forming apparatus 101 and give instructions to the image forming apparatus 101. The display unit 22 may have only a function of displaying information about the image forming process, etc., and may not have a function as an operation unit. In addition, the operation unit 20 may have a configuration in which the image forming apparatus 101 can be operated by buttons, etc.

[0045] Figure 5 is a cross-sectional view illustrating the configuration of the sheet discharge unit, and is viewed from direction B. Figure 2 The sheet discharge unit includes a double-sided flapper 12 configured to guide the sheet to a paper discharge path or a reverse path, and a triple roller including a drive roller 13 , a paper discharge roller 14 , and a reverse roller 15 .

[0046] Furthermore, the sheet discharge unit includes a stacking unit 16 on which the sheets S discharged by the driving roller 13 and the paper discharge roller 14 are stacked, and a lower guide unit 25 configured to guide the lower surface of the sheet S conveyed by the driving roller 13 and the reverse roller 15 .

[0047] The image forming apparatus 101 also includes an upper guide unit 24 fixedly provided on the image forming apparatus 101 and configured to guide the upper surface of the sheet S conveyed by the drive roller 13 and the reverse roller 15. The upper guide unit 24 extends downstream in the discharge direction of the sheet S discharged by the roller pair formed by the drive roller 13 and the reverse roller 15. In the present exemplary embodiment, the upper guide unit 24 and the upper surface cover 32 configured to cover the upper surface of the image forming apparatus 101 are separate components, but the upper guide unit 24 and the upper surface cover 32 may also be formed integrally.

[0048] When the sheet S is conveyed by the double-sided flapper 12 to the drive roller 13 and the paper discharge roller 14, the sheet S is discharged and stacked on the stacking unit 16. Furthermore, when the sheet S is conveyed by the double-sided flapper 12 located at the position indicated by the dotted line to the drive roller 13 and the reverse roller 15, a portion of the sheet S is conveyed to the outside of the apparatus above the stacking unit 16 while the lower guide unit 25 guides the lower surface side of the sheet and the upper guide unit 24 guides the upper surface side of the sheet. The drive roller 13 is then rotated in the opposite direction by a rotation direction switching unit (not shown), and the sheet S is reversed and conveyed to the inside of the apparatus.

[0049] Figure 6 yes Figure 5 The enlarged view illustrates the arrangement of the apparatus in the front-to-back direction, which is parallel to the sheet discharge direction of the sheet discharge unit. The size L1 of the operation unit 20 in the direction parallel to the sheet discharge direction and the distance L2 from the drive roller 13 to the rear cover 26 have a relationship of L1 > L2. Therefore, the operation unit 20 is arranged closer to the front surface of the image forming apparatus 101 than the drive roller 13.

[0050] A distance L3 from the operating unit 20 to the rear cover 26 and a distance L4 from the rear surface of the frame 28 configured to support the image forming unit (not shown) to the rear cover 26 have a relationship of L3>L4. That is, the operating unit 20 is arranged closer to the front side of the frame 28 than the rear side of the apparatus in the horizontal direction. This is to ensure a receiving surface for the packaging material 29 during transportation of the image forming apparatus 101.

[0051] Figure 7A and Figure 7B is a diagram illustrating an example of arrangement of the packaging material 29 of the image forming apparatus 101 during transportation of the image forming apparatus 101, Figure 7A is a top view from a vertical direction, and Figure 7B Is from Figure 2 Looking in direction B Figure 7A The graph obtained when Figure 7BIn the description, a part of the configuration of the sheet discharge unit that is not used will be omitted. Figure 7A As shown, the packaging material 29 is generally configured to receive the four corners of the image forming device 101. Figure 7B As shown, the arrangement is such that the packaging material 29 overlaps the frame 28 when viewed from the vertical direction (portion L5 ), and the packaging material 29 is provided between the operation unit 20 and the back surface of the image forming apparatus 101 (portion L3 ).

[0052] Therefore, the frame 28 can receive external force via the packaging material 29. In view of these points, in the present exemplary embodiment, the operation unit 20 is arranged in the front-rear direction of the apparatus (parallel to the sheet discharge direction) as shown in FIG. Figure 6 shown.

[0053] Figure 8A and Figure 8B : is a figure which illustrates the shape of the upper guide unit 24, Figure 8A It's a perspective drawing. Figure 8B When looking from the direction C Figure 8A The side view obtained when Figure 8A and Figure 8B In the upper guide unit 24 , the attachment shape of the upper surface cover 32 as the upper housing unit, the removal of unnecessary parts, etc. will be omitted.

[0054] Figure 9 yes Figure 5 , illustrating the relationship between the trajectory of the sheet S to be reversed and conveyed in the sheet discharge unit and the operating unit 20. A line T1, which is a first straight line, is a straight line perpendicular to a plane passing through the center of the drive roller 13 and the center of the reverse roller 15 and passing through the nip formed by the drive roller 13 and the reverse roller 15, that is, a nip tangent line T1. When viewed in the axial direction of the drive roller 13 and the reverse roller 15, the nip tangent line T1 is located at a position where the nip tangent line T1 passes through the operating unit 20 and the upper guide unit 24.

[0055] Then, in Figure 9 Line T2, which serves as the second straight line, is a straight line that contacts both the upper guide unit distal end 24a, which is the most downstream portion of the upper guide unit 24 in the direction in which the sheet S is discharged, and the lower guide unit distal end 25a, which is the point of contact between the sheet S and the lower guide unit 25. Line T2 is a straight line drawn closest to the operating unit 20 when the sheet S is discharged. The upper guide unit distal end 24a is a portion of the upper guide unit 24 and is located most downstream in the direction in which the sheet S is discharged. When viewed in the axial direction of the roller pair, line T2 does not pass through the operating unit 20, so that the sheet S to be reversed and conveyed does not contact the operating unit 20.

[0056] Therefore, the sheet S to be reversed and conveyed is conveyed as follows. First, the sheet S is conveyed in the direction of line T1 by the drive roller 13 and the reverse roller 15. Next, due to the overlapping relationship between the upper guide unit 24 and line T1, the sheet S comes into contact with the upper guide unit 24. The sheet S changes its moving direction upon contact with the upper guide unit 24 and is conveyed along the guide shape of the upper guide unit 24. Then, the sheet S is conveyed so that a portion of the sheet S is ejected to the outside of the apparatus along the trajectory of line T2, while the lower surface of the sheet S is guided by the lower guide unit 25 and the upper surface of the sheet S is guided by the upper guide unit 24.

[0057] When the driving roller 13 is rotated in the opposite direction by a rotation direction switching unit (not shown), the sheet S is reversed and conveyed along the trajectory of the line T2 in the apparatus while being similarly guided by the lower guide unit 25 and the upper guide unit 24. Therefore, the sheet S to be reversed and conveyed can be conveyed without any contact with the operation unit 20. Note that, as Figure 10 As shown, even when the operation unit 20 is in the second position, the line T2 is arranged below the operation unit 20. Therefore, as in the case where the operation unit 20 is in the first position, the sheet S to be reversed and conveyed can be conveyed without any contact with the operation unit 20.

[0058] That is, if the upper guide unit 24 were not present, the sheet S and the operating unit 20 would come into contact with each other. However, due to the presence of the upper guide unit 24, the sheet S to be discharged does not come into contact with the operating unit 20. In this exemplary embodiment, the drive roller 13 and the reverse roller 15 are configured as a reverse roller pair so that a portion of the sheet S is discharged to the outside of the image forming apparatus 101 and the sheet S is then conveyed to the inside of the image forming apparatus 101. However, other configurations are possible. For example, even if a single roller pair can be used as both a reverse roller pair and a discharge roller pair so that the drive roller 13 and the reverse roller 15 can not only reverse the sheet S but also function as a discharge roller pair to discharge the sheet S to the stacking unit 16, the same effect can be achieved. The same effect can also be achieved with a discharge roller pair in an image forming apparatus that is provided with only a single-sided printing function and does not have a sheet reversing function.

[0059] then, Figure 11 2 is a cross-sectional view illustrating the relationship between the upper guide unit 24 and the upward swing state of the detection unit 30, which is configured to detect that the number of sheets on the stacking unit has reached a predetermined number. The detection unit 30 is located below the upper guide unit 24 in the vertical direction. Figure 11The following illustrates a state where the detection unit 30 is swung upward to its maximum extent. Even when the detection unit 30 is swung upward to its maximum extent, a distance L6 is provided between the detection unit 30 and the upper guide unit 24 to prevent contact. That is, when the maximum number of sheets S are stacked on the stacking unit 16, the detection unit 30 does not come into contact with the upper guide unit 24. Therefore, even when the detection unit 30 is swung upward to its maximum extent, it does not come into contact with the upper guide unit 24 and does not block the conveying path.

[0060] Figure 12 2 is a cross-sectional view illustrating the relationship between the rotational loci of the upper guide unit 24 and the detection unit 30 .

[0061] Line 30a indicates the rotational trajectory of the detection unit 30. When the end of the detection unit 30 is located most downstream in the discharge direction of the sheet S due to the rotation, the end of the detection unit 30 is located upstream in the discharge direction of the sheet S at a distance L7 from the upper guide unit distal end 24a.

[0062] Therefore, even in the case where other sheets S are discharged to the stacking unit 16 while the sheet S is being reversed and conveyed, the reversed sheet S can be conveyed without coming into contact with the operation unit 20. Even in the case where the operation unit 20 is located at the second position, the line T2 is arranged below the operation unit 20. Therefore, as in the case where the operation unit 20 is located at the first position, the sheet S can be conveyed without any contact with the operation unit 20.

[0063] Figure 13 The relationship between the upper guide unit 24 and the sheets S stacked on the stacking unit 16 is illustrated. The number of sheets S stacked on the stacking unit 16 has reached the number predetermined by the detection unit 30. At this time, a distance L8 is provided between the stacked sheets S and the upper guide unit distal end 24a. Therefore, the sheets S to be turned over and conveyed can be conveyed without contacting the operation unit 20, and the sheets S can be stacked on the stacking unit 16 until the number of stacked sheets S reaches the number predetermined by the detection unit 30.

[0064] In this manner, with a configuration in which the upper guide unit 24 at least partially overlaps the operation unit 20 when viewed from the vertical direction and the upper guide unit 24 is located at an appropriate position, the sheet S can be conveyed without coming into contact with the operation unit 20. According to the present exemplary embodiment, the size of the image forming apparatus having a large operation unit can be reduced and the operation unit can be prevented from interfering with the discharge of the sheet.

[0065] Next, refer to Figure 14 and Figure 15A second exemplary embodiment of the present invention will be described. In this exemplary embodiment, descriptions of common portions of the first exemplary embodiment will be omitted. The difference from the first exemplary embodiment is the configuration of the guide unit. Figure 14 is a perspective view illustrating the shape of the upper guide unit 124 according to the second exemplary embodiment of the present invention, and Figure 15 is a top view illustrating the relationship between the upper guide unit 124 and the operation unit when viewed from a vertical direction. Figure 14 In the shape of the upper guide unit 124, the mounting shape of the upper surface cover 32 as the upper housing unit, the removal of unnecessary parts, etc. will be omitted. Figure 14 As shown, the upper guide unit distal end 124 a of the upper guide unit 124 on the downstream side in the discharge direction of the sheet S is only partially provided in the sheet width direction orthogonal to the discharge direction of the sheet S.

[0066] Specifically, the distance that the upper guide unit 124 extends downstream in the discharge direction of the sheet S is different in the width direction of the sheet S intersecting the discharge direction of the sheet S, and the distance at the ends in the width direction of the sheet S is longer than the distance at the center of the stacking unit 16.

[0067] like Figure 15 As shown, the width of the upper guide unit distal end 124a in the sheet width direction is longer by a distance R1 than the overlapping length between the stacking unit 16 and the operation unit 20. Therefore, the same effect as the first exemplary embodiment can be obtained, and the sheet S being conveyed does not contact the operation unit 20.

[0068] Furthermore, unlike the first exemplary embodiment, in the present exemplary embodiment, the upper guide unit distal end 124 a configured to restrict the posture of the sheet S is not arranged along the entire width above the stacking unit 16 in the sheet width direction orthogonal to the discharge direction of the sheet S. Therefore, the present exemplary embodiment can achieve a minimum arrangement to prevent the sheet S from coming into contact with the operation unit 20. Consequently, this arrangement can be improved in terms of visibility and ease of removal of the sheet discharged to the stacking unit 16, as compared with the first exemplary embodiment.

[0069] Will refer to Figure 16 and Figure 17 A third exemplary embodiment of the present invention will be described. In this exemplary embodiment, descriptions of common portions of the first exemplary embodiment will be omitted. The difference from the first exemplary embodiment is the configuration of the guide unit. Figure 16 is a perspective view illustrating the shape of a reversal guide unit according to a third exemplary embodiment of the present invention, and Figure 17 2 is a top view illustrating the relationship between the upper guide unit 224 and the operation unit 20 when viewed from the vertical direction. Figure 16In the shape of the upper guide unit 224, the mounting shape of the upper surface cover 32 as the upper housing unit, the removal of unnecessary parts, etc. will be omitted.

[0070] like Figure 16 As shown, the upper guide unit distal end 224a of the upper guide unit 224 on the downstream side in the sheet S discharge direction is only partially provided in the sheet width direction orthogonal to the sheet S discharge direction. A1 and A2, which are the upper guide unit distal ends 224a, protrude symmetrically in the sheet width direction. Similar to the second exemplary embodiment, the distance that the upper guide unit 224 extends downstream in the sheet S discharge direction varies in the sheet S width direction, and the distance at both ends in the sheet S width direction is longer than the distance at the center of the stacking unit 16.

[0071] In the sheet width direction, the width A1 of the upper guide unit distal end 224a is longer by a distance R2 than the overlapping length between the stacking unit 16 and the operating unit 20. Therefore, the same effects as those of the first and second exemplary embodiments can be obtained, and the sheet S being conveyed does not contact the operating unit 20.

[0072] In the present exemplary embodiment, the protruding distance at the center portion of the upper guide unit 224 in the sheet width direction is smaller than the protruding distances at the left and right portions of the upper guide unit 224. Therefore, as in the second exemplary embodiment, this configuration can improve visibility and ease of removal of sheets ejected to the stacking unit 16. In addition, in the present exemplary embodiment, when the upper guide unit 224 guides the sheet S being conveyed, since the shape of the upper guide unit distal end 224a is symmetrical in the sheet width direction, the conveying resistance is uniform on both sides in the sheet width direction.

[0073] Therefore, even when conveying sheets of a heavyweight type, such as thick paper, there is no difference in conveyance resistance between the left and right sides in the sheet width direction. This configuration improves not only visibility and ease of sheet removal, but also conveyance. Furthermore, in this exemplary embodiment, the shape of the upper guide unit 224 is symmetrical in the sheet width direction, thus maintaining a good appearance.

[0074] Although the exemplary embodiments of the present invention have been specifically described above, the present invention is not limited to the exemplary embodiments described above, and various modifications based on the technical concept of the present invention are possible.

[0075] According to an exemplary embodiment of the present invention, even in the case where the size of the operation unit is increased, the size of the image forming apparatus can be reduced and the operation unit can be prevented from interfering with the discharge of a sheet.

[0076] While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. The scope of the claims is to be accorded the broadest interpretation so as to encompass all such modifications, equivalent structures and functions.

Claims

1. An image forming apparatus comprising an image forming unit configured to form an image on a sheet, the image forming apparatus comprising: a roller pair configured to convey a sheet having an image formed thereon and discharge at least a portion of the sheet to the outside of the image forming apparatus; an upper guide unit fixed to the image forming apparatus and configured to guide an upper surface of a sheet discharged by the roller pair; a stacking unit provided at a position recessed from an upper housing unit of the image forming apparatus, on which discharged sheets are stacked; as well as an operation unit including a display unit configured to display information about an image forming process, the operation unit being attached to an upper housing unit of the image forming apparatus, the operation unit being configured to operate the image forming apparatus, wherein the upper guide unit extends downstream of the roller pair in the discharge direction of the sheet discharged by the roller pair, wherein the operating unit and the upper guide unit each have a portion overlapping each other when viewed from a vertical direction, and When viewed from the axial direction of the roller pair, the operating unit and the upper guide unit are arranged at positions where a straight line passes through, the straight line being orthogonal to a plane passing through the roller axes of the roller pair and passing through the clamping portion of the roller pair.

2. The image forming apparatus according to claim 1, wherein The operation unit operates the image forming apparatus in response to a touch on the display unit.

3. The image forming apparatus according to claim 1, wherein The operation unit is located inside a side surface of the image forming apparatus in a width direction of the sheet intersecting the discharge direction and is closer to the roller pair than a center of the image forming apparatus in the discharge direction.

4. The image forming apparatus according to claim 1, wherein The operation unit is held by a holding unit in the upper housing unit, and is held so as to be rotatable about a rotation center portion relative to the holding unit.

5. The image forming apparatus according to claim 1, wherein The operation unit and the stacking unit each have a portion overlapping each other when viewed from a vertical direction. 6 . The image forming apparatus according to claim 1 , further comprising a lower guide unit configured to guide a lower surface of the sheet discharged by the roller pair.

7. The image forming apparatus according to claim 6, wherein: When viewed from the axial direction of the roller pair, a straight line passing through the distal end of the lower guide unit and the distal end of the upper guide unit does not pass through the operating unit, the distal end of the lower guide unit being the contact point between the lower guide unit and the sheet, and the distal end of the upper guide unit being the most downstream part of the upper guide unit in the discharge direction.

8. The image forming apparatus according to any one of claims 1 to 5, wherein The distance that the upper guide unit extends in the sheet discharging direction is different in a width direction of the sheet intersecting the sheet discharge direction, and the distance at the width end of the sheet is longer than that at the center of the stacking unit.

9. The image forming apparatus according to any one of claims 1 to 5, wherein The roller pair is a reverse roller pair configured to discharge a portion of the sheet to the outside of the image forming apparatus and then convey the sheet to the inside of the image forming apparatus.

10. The image forming apparatus according to claim 1, further comprising a detection unit configured to detect the number of sheets stacked on the stacking unit, in, The detection unit is located below the upper guide unit in the vertical direction, and The detection unit is located at a distal end on the downstream side in the sheet discharge direction relative to a distal end of the guide unit, which is the most downstream portion of the upper guide unit in the sheet discharge direction.

11. The image forming apparatus according to claim 10, wherein When the number of sheets stacked on the stacking unit is maximum, the detecting unit does not come into contact with the upper guiding unit.

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