Image forming apparatus

Abstract

An image forming apparatus includes (i) an apparatus body including a discharge portion including a first opening and a wall disposed on an opposite side of the discharge portion with respect to a horizontal direction, the wall including a second opening, (ii) a photosensitive drum disposed below the first opening and the second opening, (iii) an exposed surface disposed below the first opening and the second opening, the exposed surface is exposed toward a first communication path communicating with the first opening and the second opening, and is disposed below the first communication path. The imaging device includes a receiving surface protruding from the exposed surface toward the first communication path. The receiving surface is upward with respect to the vertical direction and faces the first communication path. The receiving surface is inclined with respect to a vertical direction and a horizontal direction.

Description

Technical Field

[0001] The present disclosure relates to an electrophotographic image forming apparatus such as a copier, a printer, or the like. Background Art

[0002] With an image forming apparatus using an electrophotographic process, a toner image formed on a surface of a photosensitive drum as an image bearing member is transferred onto a recording medium by a transfer member and then fixed onto the recording medium by a fixing unit.

[0003] Japanese Patent Application Laid-Open No. 2001-183905 discusses an image forming apparatus using a cleaner-less method (development and cleaning are performed simultaneously) in which transfer residual toner remaining on a photosensitive drum is recovered by a developing device for reuse.

[0004] The device body of the image forming device may be provided with an opening for releasing heat and steam generated in the fixing unit to the outside of the device body. Preferably, if foreign matter such as dust enters the device body from the opening of the device body, the foreign matter should be prevented from being attached to the photosensitive drum. In particular, the image forming device using the cleaner-less method as discussed in Japanese Patent Application Publication No. 2001-183905 does not include a cleaning unit for cleaning residual toner on the photosensitive drum. Therefore, it is more preferable to prevent foreign matter from being attached to the photosensitive drum. Summary of the invention

[0005] The present disclosure is intended to prevent foreign matter from being attached to a photosensitive drum.

[0006] One aspect of the invention according to the present application will be described below.

[0007] According to one aspect of the present disclosure, an imaging device for forming an image on a recording medium, the imaging device comprising: an apparatus body, comprising a discharge portion and a wall disposed on an opposite side of the discharge portion relative to a horizontal direction, wherein the discharge portion comprises a first opening for discharging the recording medium, and the wall comprises a second opening; a photosensitive drum housed in the apparatus body, wherein the photosensitive drum is rotatable and disposed below the first opening and the second opening relative to a vertical direction; an exposed surface housed in the apparatus body, wherein the exposed surface is exposed toward a first communication path communicating with the first opening and the second opening, and is disposed below the first communication path; a plurality of ribs disposed along the rotation of the photosensitive drum The photosensitive drum is arranged in the direction of the rotation axis, wherein the multiple ribs protrude from the exposed surface toward the first connecting path, and each of the multiple ribs extends in a direction intersecting the direction of the rotation axis; and a receiving surface protrudes from the exposed surface toward the first connecting path; wherein the receiving surface is upward and faces the first connecting path relative to the vertical direction, and the receiving surface extends along the rotation axis direction in a manner connected to the multiple ribs, and is arranged to be located above the photosensitive drum relative to the vertical direction; and wherein the receiving surface is inclined relative to the vertical direction and the horizontal direction, so that the front end of the receiving surface is arranged above the root of the receiving surface connected to the exposed surface.

[0008] Further features of the present disclosure 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 cross-sectional view showing the imaging apparatus.

[0010] Figure 2A and Figure 2B is a schematic cross-sectional view showing an image forming apparatus.

[0011] Figure 3 is a schematic cross-sectional view showing an image forming apparatus.

[0012] Figure 4 is another schematic cross-sectional view illustrating the imaging apparatus.

[0013] Figure 5 is another schematic cross-sectional view showing the imaging apparatus.

[0014] Figure 6 is another schematic cross-sectional view showing the imaging apparatus.

[0015] Figure 7 The toner is shown attached to the recording medium.

[0016] Fig. 8A and Figure 8B is a cross-sectional view showing a double-sided printing guide and a transfer guide according to a comparative example.

[0017] Fig.9A and Fig. 9B A double-sided printing guide and a transfer guide according to the present exemplary embodiment are shown.

[0018] Fig. 10A and Fig. 10B A double-sided printing guide according to the present exemplary embodiment is shown.

[0019] Fig.11A and Fig. 11B is a cross-sectional view illustrating a double-sided printing guide and a transfer guide according to the present exemplary embodiment.

[0020] Fig. 12A and Fig. 12B are other cross-sectional views illustrating the double-sided printing guide and the transfer guide according to the present exemplary embodiment.

[0021] Fig.13A and Fig. 13B A transfer guide according to the present exemplary embodiment is shown.

[0022] Fig.14A and Fig. 14B are other cross-sectional views illustrating the double-sided printing guide and the transfer guide according to the present exemplary embodiment.

[0023] Fig.15A and Fig. 15B are other cross-sectional views illustrating the double-sided printing guide and the transfer guide according to the present exemplary embodiment.

[0024] Fig.16 is a cross-sectional view illustrating a double-sided printing guide and a transfer guide according to the present exemplary embodiment. DETAILED DESCRIPTION

[0025] The exemplary embodiments of the present disclosure will be described in detail below with reference to the accompanying drawings. However, the size, material, shape and relative arrangement of the components according to the following exemplary embodiments should be modified as needed depending on the configuration of the device according to the present disclosure and other various conditions. Therefore, unless otherwise specifically described, the scope of the present disclosure is not limited to the following exemplary embodiments.

[0026] (Overall Structure of Imaging Device)

[0027] The following will refer to Figure 1 , Figure 2A , Figure 2B and Figure 3 The overall configuration of the imaging apparatus 100 is described. Figure 1 is a cross-sectional view showing the imaging apparatus 100 . Figure 2A and Figure 2B1 is a schematic cross-sectional view illustrating the conveyance of the recording medium P in the image forming apparatus 100 . Figure 3 1 is a schematic cross-sectional view illustrating the movement of the door 12 and the transfer guide 13 of the image forming apparatus 100 . Figure 1 , Figure 2A , Figure 2B and Figure 3 The image forming apparatus 100 is shown when viewed from the rotation axis direction of a photosensitive drum 1 (described below).

[0028] In the following description, the vertical direction in a state where the imaging device 100 is set on a horizontal surface is referred to as the Z direction. The Z direction is opposite to the gravity direction. The height direction of the imaging device 100 is a direction parallel to the Z direction and opposite to the gravity direction. The direction perpendicularly intersecting the Z direction and parallel to the rotation axis direction (main scanning direction or longitudinal direction) of the photosensitive drum 1 is referred to as the X direction. The direction perpendicularly intersecting the X direction and the Z direction is referred to as the Y direction. The X direction and the Y direction are parallel to the horizontal direction. For convenience, the positive side of the X direction is referred to as the right-hand side, and the negative side of the X direction is referred to as the left-hand side; the positive side of the Y direction is referred to as the front side, and the negative side of the Y direction is referred to as the rear side; the positive side of the Z direction is referred to as the upper side, and the negative side of the Z direction is referred to as the lower side.

[0029] The image forming apparatus 100 forms an image on a recording medium (sheet) P. The image forming apparatus 100 according to the present exemplary embodiment is a monochrome laser beam printer that adopts a cleaner-less method.

[0030] The imaging device 100 includes an apparatus main body 100a. The apparatus main body 100a accommodates an imaging unit IM, an exposure device 3, a fixing unit 9, a duplex printing guide (opposite member) 11, and a transfer guide (opening and closing member) 13. More specifically, the apparatus main body 100a includes a housing 100c and a door 12 that can be opened and closed relative to the housing 100c. The imaging unit IM, the exposure device 3, the fixing unit 9, the duplex printing guide 11, and the transfer guide 13 are accommodated in the housing 100c. The apparatus main body 100a includes a control unit (controller) for performing an imaging operation based on image information received from an external device.

[0031] The apparatus body 100a includes: a discharge portion 14 having a first opening 14a for discharging the recording medium P; and a wall 16a which is provided on the opposite side of the discharge portion 14 in the horizontal direction and has a second opening 16. The wall 16a having the second opening 16 is a part of the door 12. The discharge portion 14 included in the housing 100c includes a discharge roller pair 14b.

[0032] The imaging unit IM includes a cylindrical electrophotographic photosensitive member (hereinafter referred to as a photosensitive drum) 1 as an image bearing member, a charging roller 2 as a charging member, and a developing device 4 as a developing unit. The photosensitive drum 1 can rotate around a rotation axis. The rotation axis direction of the photosensitive drum 1 is parallel to the X direction.

[0033] A first communication path CP1 communicating with the first opening 14a and the second opening 16 is formed in the apparatus body 100a. The photosensitive drum 1 is housed in the apparatus body 100a and arranged below the first opening 14a, the second opening 16 and the first communication path CP1 in the Z direction.

[0034] In addition to the charging roller 2 and the developing device 4, an exposure device 3 as an exposure unit, a transfer roller 5 as a transfer unit, and a pre-exposure device 6 are also provided around the photosensitive drum 1. The exposure device 3, the transfer roller 5, and the pre-exposure device 6 may be referred to as a part of the imaging unit IM.

[0035] The control unit starts the image forming operation based on the image information from the external device. When the image forming operation starts, the photosensitive drum 1 rotates in the direction of the arrow R1. Figure 2A shown.

[0036] The surface of the photosensitive drum 1 is charged to a predetermined potential having a predetermined polarity (negative polarity in the present exemplary embodiment) by a charging roller 2 in contact with the photosensitive drum 1. The charged surface of the photosensitive drum 1 is exposed according to image information by an exposure device 3. Thus, an electrostatic latent image corresponding to the image information is formed on the surface of the photosensitive drum 1. The electrostatic latent image is developed by a developing device 4 at a developing position to be visualized as a toner image.

[0037] The charging roller 2 has an elastic layer made of a conductive elastic member, and the surface roughness Ra is 1.5 to 2.5 μm. The charging roller 2 contacts the surface of the photosensitive drum 1 with a predetermined contact pressure. The position where the charging roller 2 and the photosensitive drum 1 contact each other is called a charging portion. The charging roller 2 is driven by a driving mechanism (not shown) so that the circumferential speed of the charging roller 2 becomes 105% of the circumferential speed of the photosensitive drum 1. A predetermined direct current (DC) voltage is applied to the shaft of the charging roller 2 by a charging voltage power supply. According to the present exemplary embodiment, a DC voltage of -1350V is applied to the shaft of the charging roller 2 as a charging voltage. The surface of the photosensitive drum 1 charged by the charging roller 2 has a predetermined potential (dark portion potential) of -780V.

[0038] The exposure device 3 as a laser scanning device irradiates the photosensitive drum 1 with a laser beam based on image information to form an electrostatic latent image on the surface of the photosensitive drum 1. According to the present exemplary embodiment, the portion on the surface of the photosensitive drum 1 exposed by the exposure device 3 has a predetermined potential (bright portion potential) of -100 V. According to the present exemplary embodiment, toner is supplied from the developing device 4 to the surface of the photosensitive drum 1 having the bright portion potential, and toner from the developing device 4 is not supplied to the surface of the photosensitive drum 1 having the dark portion potential.

[0039] The developing device 4 includes a developing roller 41 as a developer carrying member, a toner supplying roller 42 as a developer supplying unit, a developer containing chamber 43 for containing toner, and a developing blade 44 as a layer regulating member. The developing device 4 includes a toner conveying member for conveying the toner contained in the developer containing chamber 43 to the toner supplying roller 42. The toner supplied from the developer containing chamber 43 is supplied to the developing roller 41 by the toner supplying roller 42. The developing blade 44 is in contact with the developing roller 41. When the developing roller 41 rotates, the toner supplied to the developing roller 41 passes through the contact portion between the developing blade 44 and the developing roller 41. As a result, the toner carried by the developing roller 41 is charged to a predetermined polarity (normal charging polarity), and a toner layer having a predetermined thickness is formed on the surface of the developing roller 41.

[0040] The toner used was a non-magnetic single-component toner having a negative polarity produced by a suspension polymerization method. The volume average particle diameter of the toner was 6.0 μm, and the normal charging polarity was negative.

[0041] The developing roller 41 contacts the surface of the photosensitive drum 1 with a predetermined contact pressure. The portion where the developing roller 41 and the photosensitive drum 1 contact each other is called a developing portion. The developing roller 41 is driven by a driving mechanism (not shown) so that the peripheral speed of the developing roller 41 becomes 140% of the peripheral speed of the photosensitive drum 1. A DC voltage of -380V is applied to the shaft of the developing roller 41 by a developing voltage power supply. In the image forming process, the toner carried on the developing roller 41 is developed to the portion of the photosensitive drum 1 having the bright portion potential by the electrostatic force generated by the potential difference between the -380V developing voltage and the -100V bright portion potential of the photosensitive drum 1.

[0042] The area on the surface of the photosensitive drum 1 to which the toner can be supplied from the developing roller 41 may be referred to as an image forming area on the photosensitive drum 1. The image forming area on the photosensitive drum 1 may be an area that can be exposed by the exposure device 3, or may be an area corresponding to a toner coating area on the surface of the developing roller 41 coated with toner.

[0043] The transfer roller 5 facing the photosensitive drum 1 contacts the surface of the photosensitive drum 1 at a predetermined contact pressure. Therefore, a transfer portion is formed between the transfer roller 5 and the photosensitive drum 1. When a transfer voltage power supply applies a predetermined voltage to the shaft of the transfer roller 5 at a predetermined timing, the toner image formed on the surface of the photosensitive drum 1 is transferred onto the recording medium P at the transfer portion.

[0044] The pre-exposure device 6 exposes the surface of the photosensitive drum 1 that has passed through the transfer section but has not yet reached the charging section. This eliminates the uneven surface potential of the photosensitive drum 1. The toner that is not transferred to the recording medium P and remains on the photosensitive drum 1 passes through the charging section and is then recovered by the developing roller 41.

[0045] The image forming apparatus 100 includes, at a lower portion, a tray 10 as a recording medium storage unit (sheet storage unit) for storing sheets of recording media P and a sheet feeding unit 7. The sheet feeding unit 7 includes a pickup roller 7a, a feeding roller 7b, and a separation roller 7c.

[0046] The pickup roller 7a rotates in contact with the top sheet of the recording medium P stacked on the tray 10 to send the top sheet of the recording medium P from the tray 10. The recording medium P sent out from the tray 10 is further conveyed, and each sheet is separated at a nip (separation nip) between the feed roller 7b and the separation roller 7c.

[0047] The apparatus body 100a includes a conveying unit 8, which includes a conveying roller 8a, a first driven roller 8b, and a second driven roller 8c. The conveying roller 8a is driven by a motor, and the first driven roller 8b and the second driven roller 8c are driven by the conveying roller 8a. The recording medium P that has passed through the separation nip is conveyed toward the transfer portion by the conveying roller 8a and the first driven roller 8b in contact with the conveying roller 8a.

[0048] In synchronization with the time when the toner image formed on the photosensitive drum 1 reaches the transfer section, the recording medium P accommodated in the tray 10 is conveyed to the transfer section by the sheet feeding unit 7 and the conveying roller 8. The toner image formed on the photosensitive drum 1 is transferred to the recording medium P by the transfer roller 5 to which a predetermined transfer voltage is applied by a transfer voltage power supply.

[0049] A fixing unit 9 configured to heat the recording medium P is provided above the photosensitive drum 1. The fixing unit 9 includes a heating roller having a built-in heater and a pressure roller biased toward the heating roller at a predetermined pressure. A conveying path SP1 is formed downstream of the transfer section and upstream of the fixing unit 9 in the conveying direction of the recording medium P. After passing through the transfer section, the recording medium P conveyed from the photosensitive drum 1 toward the fixing unit 9 passes through the conveying path SP1.

[0050] The second communication path CP2 is formed above the photosensitive drum 1 and below the first communication path CP1. The second communication path CP2 communicates with the transport path SP1 and the first communication path CP1.

[0051] When the recording medium P conveyed to the fixing unit 9 is heated and pressurized by the fixing unit 9 , the toner image transferred onto the recording medium P is fixed onto the recording medium.

[0052] The recording medium P to which the toner image is fixed is discharged from the first opening 14a to the outside of the apparatus body 100a. The apparatus body 100a is provided with a sheet discharge tray 15 for stacking sheets of recording medium P. The recording medium P discharged from the first opening 14a is stacked on the sheet discharge tray 15.

[0053] When the recording medium P is heated, steam is generated from the recording medium P. The steam generated from the recording medium P is discharged to the outside of the device body 100a via the second opening (exhaust port) 16. According to the present exemplary embodiment, the device body 100a (housing 100c) is provided with an upper opening 100d above the first communication path CP1. The upper opening 100d includes a plurality of holes, and the steam is discharged to the outside of the device body 100a via the upper opening 100d.

[0054] According to the present exemplary embodiment, the image forming apparatus 100 can perform single-sided printing for forming an image on one side of the recording medium P and double-sided printing for forming images on both sides of the recording medium P.

[0055] When single-sided printing is performed, the recording medium P is conveyed in the P1 direction by the discharge roller pair 14b and then discharged onto the sheet discharge tray 15. Figure 2A When double-sided printing is performed, the recording medium P with a toner image fixed on one side is conveyed by the discharge roller pair 14b in the direction of arrow P1. Then, the rotation direction of the discharge roller pair 14b is reversed, and the recording medium P is conveyed in the direction of arrow P2, as shown in FIG. Figure 2B shown.

[0056] The recording medium P transported in the P2 direction passes through the double-sided transport path SP2, and is then transported to the nip portion between the first driven roller 8b and the transport roller 8a by the second driven roller 8c and the transport roller 8a. Then, the recording medium P having a toner image formed on the back surface at the transfer portion passes through the fixing unit 9, and is then discharged onto the sheet discharge tray 15.

[0057] According to the present exemplary embodiment, the first communication path CP1 is a part of the duplex transport path SP2. The duplex printing guide 11 and the transfer guide 13 serve as guide members that guide the recording medium P passing through the duplex transport path P2.

[0058] The image forming operation on the recording medium P reduces the amount of toner in the developing device 4. The image forming apparatus 100 according to the present exemplary embodiment can supply toner to the developing device 4 from a replenishing container TP that is attachable to and detachable from the image forming apparatus 100. Figure 1 As shown, the apparatus body 100a of the image forming apparatus 100 is provided with a replenishment receiving member 100R. A replenishment container TP is detachably attached to the replenishment receiving member 100R. Toner is supplied to the developing device 4 from the replenishment container TP attached to the replenishment receiving member 100R via a toner flow path (not shown).

[0059] According to the present exemplary embodiment, the sheet discharge tray 15 is used as a cover that can open and close to cover the replenishment receiving member 100R. The sheet discharge tray 15 can move between a covering position for covering the replenishment receiving member 100R and a replenishment position for exposing the replenishment receiving member 100R. The sheet discharge tray 15 can rotate relative to the housing 100c around the rotation center 15a. When the recording medium P discharged from the first opening 14a is stacked on the sheet discharge tray 15, the sheet discharge tray 15 is positioned in the covering position. When the sheet discharge tray 15 moves from the covering position to the replenishment position, the sheet discharge tray 15 moves in a direction close to the first opening 14a. When the sheet discharge tray 15 is in the replenishment position, the first opening 14a is covered by the sheet discharge tray 15a, so the discharge of the recording medium P from the first opening 14a and the imaging operation on the recording medium P are restricted.

[0060] If the recording medium P is jammed, that is, if a jam occurs in the image forming apparatus 100, the user performs so-called jam removal to remove the recording medium P from the image forming apparatus 100. Therefore, the door 12 and the transfer guide 13 of the image forming apparatus 100 according to the present exemplary embodiment are configured to be openable and closable. The door 12 is rotatable around the rotation center 121, and the transfer guide 13 is rotatable around the rotation center 131 (see FIG. 1 ). Figure 1 ). The rotation center 131 of the transfer guide 13 coincides with the rotation center of the conveying roller 8a. The rotation center 131 of the transfer guide 13 is disposed below the photosensitive drum 1 with respect to the vertical direction.

[0061] The transfer guide 13 is an opening and closing member that can be moved between a closed position for covering the photosensitive drum 1 and an open position for exposing the photosensitive drum 1. In a state where the transfer guide 13 is in the closed position, the upper end of the transfer guide 13 is located above the photosensitive drum 1 with respect to the vertical direction. When the transfer guide 13 supporting the transfer roller 5 is in the closed position, the transfer roller 5 is in contact with the photosensitive drum 1. When the transfer guide 13 is in the open position, the transfer roller 5 is separated from the photosensitive drum 1. The transfer guide 13 is biased from the open position toward the closed position by a spring (not shown). The transfer guide 13 can be opened and closed in conjunction with the opening and closing operation of the door 12.

[0062] If the recording medium P is jammed between the conveying unit 8 and the fixing unit 9, the user opens the door 12 and moves the transfer guide 13 to the open position, as shown in FIG. Figure 3 In this state, the user can remove the recording medium P to perform jam clearing. If the recording medium P is jammed in the duplex transport path SP2, the user can simply open the door 12 and perform jam clearing.

[0063] After the jam clearing is completed, when the transfer guide 13 is moved to the closed position and the door 12 is closed, the image forming apparatus 100 is ready to resume the image forming operation.

[0064] <Intrusion of foreign matter such as dust>

[0065] The following will refer to Figure 4 , Figure 5 and Figure 6 A case where foreign matter such as dust intrudes into the second opening 16 and the imaging device 100 is described. Figure 4 , Figure 5 and Figure 6 is a schematic cross-sectional view showing the imaging apparatus 100 .

[0066] As described above, the apparatus body 100a includes the wall 16a (see FIG. 10a ) which is disposed on the opposite side of the discharge portion 14 in the horizontal direction and has the second opening 16. Figure 1 ). Wall 16a is a part of door 12. Figure 4 As shown, the second opening 16 includes a plurality of holes, and communicates between the interior of the apparatus body 100a (the first communication path CP1 and the two-sided conveying path SP2) and the exterior of the apparatus body 100a.

[0067] The second opening 16 is located above the photosensitive drum 1 and the fixing unit 9 (more specifically, the fixing nip) with respect to the vertical direction. The range where the image forming area exists on the photosensitive drum 1 overlaps with the range where the second opening 16 exists with respect to the rotation axis direction of the photosensitive drum 1.

[0068] The first communication path CP1 communicating with the first opening 14a and the second opening 16 serves as an air path. More specifically, air can flow from the first opening 14a to the second opening 16, as shown in FIG. Figure 5 As shown by arrow A1 in Figure 5 In the direction opposite to the arrow A1, air may also flow from the second opening 16 to the first opening 14a. These air flows may be generated by air conditioning and ventilation facilities in the room where the imaging device 100 is installed.

[0069] The double-sided printing guide 11 is located below the first communication path CP1 with respect to the vertical direction and faces the first communication path CP1. When viewed in the rotation axis direction of the photosensitive drum 1, the double-sided printing guide 11 is disposed between the first opening 14a and the second opening 16 in the horizontal direction. The double-sided printing guide 11 is disposed above the photosensitive drum 1 with respect to the vertical direction. When viewed in the rotation axis direction of the photosensitive drum 1, the photosensitive drum 1 is disposed between the first opening 14a and the door 12 in the horizontal direction, that is, between the first opening 14a and the second opening 16.

[0070] If foreign matter D1 such as dust exists in a large amount in the air and the air flow through the first communication path CP1 is strong, the foreign matter D1 such as dust may enter the image forming apparatus 100 together with the air passing through the first communication path CP1 and then accumulate on the duplex printing guide 11. In this case, the foreign matter D1 may include foreign matter D1 that is connected to the image forming apparatus 100 along the first communication path CP1. Figure 5 The air flowing in the direction of the arrow A1 may include the foreign matter D1 entering the imaging device 100 together with the air flowing in the direction opposite to the arrow A1 .

[0071] For example, the vibration generated when the door 12 or the transfer guide 13 is closed may cause the foreign matter D1 accumulated on the duplex printing guide 11 to fall from the duplex printing guide 11 to the negative side in the Z direction. According to the present exemplary embodiment, the transfer guide 13 is biased by a spring, and therefore, the vibration generated when the transfer guide 13 is closed tends to be greater than the vibration generated when the door 12 is closed.

[0072] In the configuration in which the photosensitive drum 1 is disposed below the duplex printing guide 11 , the foreign matter D1 may fall near the photosensitive drum 1 .

[0073] According to the present exemplary embodiment, for example, Figure 1 and Figure 6 As shown, when the transfer guide 13 located below the double-sided printing guide 11 is in the closed position, a second communication path CP2 is formed between the transfer guide 13 and the double-sided printing guide 11. The second communication path CP2 is connected to the conveying path SP1 and the first communication path CP1. Figure 6 As shown, the foreign matter D1 may drop to the vicinity of the photosensitive drum 1 via the second communication path CP2.

[0074] When the transfer guide 13 is in the open position, the photosensitive drum 1 is exposed. When the transfer guide 13 moves from the open position to the closed position, the foreign matter D1 may fall near the photosensitive drum 1.

[0075] Figure 7The toner is shown to be attached to the recording medium P. For example, if the photosensitive drum 1 has damage exceeding a predetermined depth, the charge retention capability of the surface of the photosensitive drum 1 is reduced. Therefore, the toner supplied from the developing roller 41 to the damaged portion (the portion on the surface of the photosensitive drum 1 where the charge retention capability is reduced) is periodically attached to the recording medium P. Figure 7 In the illustrated example, the attachment of toner is repeated in one rotation cycle of the photosensitive drum 1 .

[0076] As described above, if the image forming apparatus 100 is used in an environment where a large amount of foreign matter D1 such as dust exists in the air and the air flow through the first communication path CP1 is strong and toner adhesion is caused by the foreign matter D1 attached to the photosensitive drum 1 , it is necessary to replace the photosensitive drum 1 .

[0077] <Structure to prevent foreign matter from adhering to the photosensitive drum>

[0078] Fig. 8A and Figure 8B is a cross-sectional view showing a double-sided printing guide 11 ′ and a transfer guide 13 ′ according to a comparative example. Fig. 8A , the transfer guide 13' is in the open position. Figure 8B According to the comparative example, since the duplex printing guide 11' has no portion for preventing the foreign matter D1 from falling, the foreign matter D1 accumulated on the duplex printing guide 11' falls near the photosensitive drum 1.

[0079] The following will refer to Fig.9A , Fig. 9B , Fig. 10A , Fig. 10B , Fig.11A , Fig. 11B , Fig. 12A and Fig. 12B A configuration for preventing the foreign matter D1 from adhering to the photosensitive drum 1 is described.

[0080] Fig.9A and Fig. 9B The double-sided printing guide 11 and the transfer guide 13 according to the present exemplary embodiment are shown. Fig.9A The transfer guide 13 is shown in the closed position. Fig. 9B A state in which the transfer guide 13 is in the open position is shown. Fig.9A and Fig. 9B is a diagram when the imaging apparatus 100 is viewed in the Y direction. Fig. 9B The arrow 1 a in denoted the direction of the rotation axis of the photosensitive drum 1 .

[0081] Fig. 10A and Fig. 10B A double-sided printing guide 11 according to the present exemplary embodiment is shown. Fig. 10AThe duplex printing guide 11 is shown as viewed from the vertical direction, more specifically, from the direction opposite to the Z direction. Fig. 10B 1 is a perspective view showing the double-sided printing guide 11 .

[0082] Fig.11A , Fig. 11B , Fig. 12A and Fig. 12B : is a cross-sectional view showing the double-sided printing guide 11 and the transfer guide 13 according to the present exemplary embodiment. Fig.11A , Fig. 11B , Fig. 12A and Fig. 12B 1 is a cross-sectional view showing the double-sided printing guide 11 and the transfer guide 13 according to the present exemplary embodiment, taken in a direction perpendicularly intersecting the rotation axis direction of the photosensitive drum 1 when viewed from the rotation axis of the photosensitive drum 1 .

[0083] The double-sided printing guide 11 according to the present exemplary embodiment includes receiving ribs (receiving protrusions) 11 b 1 and 11 b 2 .

[0084] The receiving ribs 11b1 and 11b2 capture the foreign matter D1 to prevent it from being attached to the photosensitive drum 1. The shape of the double-sided printing guide 11 will be described in more detail below.

[0085] The double-sided printing guide 11 housed in the device body 100A includes an exposed surface 11c exposed toward the first communicating path CP1. The exposed surface 11c is arranged below the first communicating path CP1. The state in which the exposed surface 11c is exposed toward the first communicating path CP1 means that the exposed surface 11c can be seen from any position in the first communicating path CP1. The exposed surface 11c can be said to be an opposite surface facing the first communicating path CP1.

[0086] like Fig. 10B and Fig.11A As shown, the exposed surface 11c has a curved surface that is curved upward relative to the vertical direction. The curved surface of the exposed surface 11c includes a vertex 11c0 at the highest position relative to the vertical direction, a first surface 11c1, and a second surface 11c2. Fig.11A As shown, when viewed from the rotation axis direction of the photosensitive drum 1 , the first surface 11 c 1 is located on one side of the vertex 11 c 0 , and the second surface 11 c 2 is located on the other side of the vertex 11 c 0 .

[0087] When viewed in the direction of the rotation axis of the photosensitive drum 1, the apex 11c0 is located between the first opening 14a and the second opening 16 in the horizontal direction. Figure 1Apex 11c0 is closer to second opening 16 than to first opening 14a when viewed from the rotation axis direction of photosensitive drum 1. More specifically, in the horizontal direction, the distance between apex 11c0 and second opening 16 is shorter than the distance between apex 11c0 and first opening 14a.

[0088] When viewed in the rotation axis direction of the photosensitive drum 1, the first surface 11c1 is closer to the second opening 16 than the vertex 11c0 in the horizontal direction. More specifically, in the horizontal direction, the distance between the first surface 11c1 and the second opening 16 is shorter than the distance between the vertex 11c0 and the second opening 16. When viewed in the rotation axis direction of the photosensitive drum 1, the second surface 11c2 is closer to the first opening 14a than the vertex 11c0 in the horizontal direction. More specifically, in the horizontal direction, the distance between the second surface 11c2 and the first opening 14a is shorter than the distance between the vertex 11c0 and the first opening 14a.

[0089] The first surface 11c1 and the second surface 11c2 are inclined downward from the vertex 11c0. In other words, the first surface 11c1 and the second surface 11c2 extend downward in the vertical direction as they separate from the vertex 11c0 in the horizontal direction. According to the present exemplary embodiment, the first surface 11c1 and the second surface 11c2 each include a curved portion.

[0090] like Fig. 10A and Fig. 10B As shown, the duplex printing guide 11 has a plurality of first ribs 11a1 and a plurality of second ribs 11a2. The plurality of first ribs 11a1 and the plurality of second ribs 11a2 protrude from the exposed surface 11c toward the first communicating path CP1. The plurality of first ribs 11a1 are arranged discretely from each other and arranged along the rotation axis direction of the photosensitive drum 1. The plurality of second ribs 11a2 are arranged along the rotation axis direction of the photosensitive drum 1.

[0091] Each of the plurality of first ribs 11a1 and each of the plurality of second ribs 11a2 extends in a direction intersecting the direction of the rotation axis of the photosensitive drum 1. According to the present exemplary embodiment, the first communication path CP1 is used as a conveying path through which the recording medium P can pass. More specifically, the first communication path CP1 is a part of the double-sided conveying path SP2. The plurality of first ribs 11a1 and the plurality of second ribs 11a2 extend along the conveying direction of the recording medium P passing through the first communication path CP1, and have a function of guiding the recording medium P passing through the first communication path CP1.

[0092] like Fig. 10BAs shown, the back side of the duplex printing guide 11 is provided with receiving ribs 11b1 and 11b2 protruding from the exposed surface 11c of the duplex printing guide 11. For each of the receiving ribs 11b1 and 11b2, the top surface (the surface oriented upward relative to the vertical direction) serves as a receiving surface for receiving the foreign matter D1. In other words, the duplex printing guide 11 has a plurality of receiving members (which are the top surfaces of the receiving ribs 11b1 and 11b2).

[0093] According to the present exemplary embodiment, the duplex printing guide 11 has a plurality of receiving ribs 11b1 and a plurality of receiving ribs 11b2. The shapes of the plurality of receiving ribs 11b1 are substantially the same, and the shapes of the plurality of receiving ribs 11b2 are also substantially the same. One or more receiving ribs 11b1 and one or more receiving ribs 11b2 may be provided. The duplex printing guide 11 may have either one of the ribs 11b1 and 11b2.

[0094] The top surfaces of the receiving ribs 11b1 and 11b2 protrude from the exposed surface 11c toward the first communicating path CP1 and face the first communicating path CP1. At least a portion of the top surfaces of the receiving ribs 11b1 and 11b2 is located directly below the first communicating path CP1. Therefore, the top surfaces of the receiving ribs 11b1 and 11b2 can receive foreign matter D1 that falls downward from the first communicating path CP1.

[0095] The top surfaces of the receiving ribs 11b1 and 11b2 extend in the rotation axis direction of the photosensitive drum 1 in such a manner as to be connected to the plurality of second ribs 11a2. This prevents the foreign matter D1 from falling from the top surfaces of the receiving ribs 11b1 and 11b2.

[0096] The top surfaces of the receiving ribs 11b1 and 11b2 are located above the photosensitive drum 1 with respect to the vertical direction. The top surfaces of the receiving ribs 11b1 and 11b2 are located above the second communication path CP2 with respect to the vertical direction.

[0097] from Fig. 9B It can be seen that the positions of the top surfaces of the receiving ribs 11b1 and 11b2 overlap with the position of the photosensitive drum 1 relative to the rotation axis direction of the photosensitive drum 1. Preferably, the length of the plurality of receiving members (the total length of the top surfaces of the receiving ribs 11b1 and 11b2) relative to the rotation axis direction of the photosensitive drum 1 is 50% or more of the length of the imaging area on the photosensitive drum 1.

[0098] Although the receiving ribs 11b1 and 11b2 are provided at positions other than the longitudinal center of the duplex printing guide 11 according to the present exemplary embodiment, they may be provided in a region including the longitudinal center. Even if the receiving ribs 11b1 and 11b2 are provided without being connected to the second rib 11a2, the foreign matter D1 can be prevented from falling.

[0099] The top surfaces of the receiving ribs 11 b 1 and 11 b 2 , the exposed surface 11 c , and the plurality of second ribs 11 a 2 form a space for receiving the foreign matter D1 , thereby preventing the foreign matter D1 from falling and adhering to the photosensitive drum 1 .

[0100] like Fig. 12A and Fig. 12B As shown, when viewed from the rotation axis direction of the photosensitive drum 1, the top surfaces of the receiving ribs 11b1 and 11b2 are closer to the second opening 16 than to the first opening 14a. More specifically, the distance between each top surface of the receiving ribs 11b1 and 11b2 and the second opening 16 is shorter than the distance between each top surface of the receiving ribs 11b1 and 11b2 and the first opening 14a. The top surfaces of the receiving ribs 11b1 and 11b2 protrude from the exposed surface 11c toward the second opening 16.

[0101] Although the top surfaces of the receiving ribs 11b1 and 11b2 may extend horizontally, it is preferred that the top surfaces extend upward in a direction intersecting the horizontal and vertical directions. More specifically, the top surfaces of the receiving ribs 11b1 and 11b2 are preferably inclined relative to the vertical and horizontal directions so that the front end of the top surface is located above the root connected to the exposed surface 11c.

[0102] The first surface 11c1 of the exposed surface 11c is located between the vertex 11c0 and the front end of the top surface of the receiving ribs 11b1 and 11b2 in the horizontal direction when viewed in the rotation axis direction of the photosensitive drum 1. Therefore, the foreign matter D1 dropped from the first surface 11c1 is received by the top surfaces of the receiving ribs 11b1 and 11b2.

[0103] If foreign matter D1 adheres to the photosensitive drum 1, it will cause Figure 7 The foreign matter D1 attached to the toner shown often has a size of several tens to several hundreds of micrometers (μm). Therefore, preferably, the top surfaces of the receiving ribs 11b1 and 11b2 protrude from the exposed surface 11c by a length of 1 mm or more (hereinafter, this length is simply referred to as the protrusion length). If the opening and closing operation of the transfer guide 13 causes a strong impact, a longer protrusion length is more preferred in order to prevent the foreign matter D1 from falling from the top surfaces of the receiving ribs 11b1 and 11b2.

[0104] On the other hand, according to the present exemplary embodiment, the second rib 11a2 is used as a guide rib for guiding the recording medium P. The receiving ribs 11b1 and 11b2 extend from the exposed surface 11c in a direction opposite to the conveying direction of the recording medium P. The protruding height is shorter than the protruding length of the second rib 11a2 protruding from the exposed surface 11c. This prevents the top surfaces of the receiving ribs 11b1 and 11b2 from contacting the recording medium P.

[0105] like Fig. 12A and Fig. 12BAs shown, the front ends of the top surfaces of the receiving ribs 11b1 and 11b2 protrude more in the -Y direction than the back surface of the transfer guide 13. The front ends of the top surfaces of the receiving ribs 11b1 and 11b2 protrude more in the -Y direction than the end of the second communication path CP2 formed by the duplex printing guide 11 and the transfer guide 13.

[0106] Therefore, even if the foreign matter D1 falls from the top surfaces of the receiving ribs 11b1 and 11b2, the foreign matter D1 is prevented from entering the second communicating path CP2, and is difficult to fall near the photosensitive drum 1. The transfer guide 13 is provided with guide ribs for guiding the recording medium P passing through the double-sided transport path SP2. The back surface of the transfer guide 13 refers to the surface between the guide ribs of the transfer guide 13.

[0107] Fig. 8A and Figure 8B The case where the receiving rib 11b2 is not provided is shown. In this case, if the foreign matter D1 on the duplex printing guide 11 falls due to the vibration that occurs when the transfer guide 13 is closed, the foreign matter D is likely to enter the gap between the duplex printing guide 11 and the transfer guide 13 and fall onto the photosensitive drum 1. On the other hand, if the receiving ribs 11b1 and 11b2 are provided, the top surfaces of the receiving ribs 11b1 and 11b2 block the gap between the duplex printing guide 11 and the transfer guide 13 when viewed from the positive side in the Z direction. The top surfaces of the receiving ribs 11b1 and 11b2 receive the foreign matter D1 to prevent the foreign matter D1 from falling onto the photosensitive drum 1.

[0108] The effects of the double-sided printing guide 11 according to the present exemplary embodiment will be described below. Fig. 8A and Figure 8B The construction of the double-sided printing guide 11' of the comparative example shown was compared with the construction including the double-sided printing guide 11 according to the present exemplary embodiment for the case where the foreign matter D1 was attached to the photosensitive drum 1. More specifically, 0.5 g of mineral powder simulating dust was uniformly sprayed on the double-sided printing guides 11 and 11' in the longitudinal direction. The mineral powder included silicon dioxide having a particle size of several tens of micrometers to several hundreds of micrometers. Then, the opening and closing operation of the transfer guide 13 was performed five times, and the number of mineral powder particles attached to the photosensitive drum 1 was counted. The double-sided printing guide 11 according to the present exemplary embodiment and the double-sided printing guide according to the comparative example were evaluated three times, respectively.

[0109] Table 1 shows evaluation results of the configuration A including the double-sided printing guide 11 according to the present exemplary embodiment and the comparative example including the double-sided printing guide 11 ′.

[0110] Table 1

[0111] First evaluation Second evaluation The third evaluation Comparative Example 60 72 55 Structure A 30 34 28

[0112] Referring to Table 1, the duplex printing guide 11 according to the present exemplary embodiment reduces the amount of mineral powder particles to about half that according to the comparative example, and provides an effect of preventing foreign matter D1 on the duplex printing guide 11 from being attached to the photosensitive drum 1 .

[0113] According to the present exemplary embodiment, the receiving ribs 11b1 and 11b2, the exposed surface 11c, and the second rib 11a2 are integrally provided on the duplex printing guide 11. However, the receiving ribs 11b1 and 11b2, the exposed surface 11c, and the second rib 11a2 may be divided into a plurality of parts.

[0114] (Transfer guide)

[0115] In addition to the receiving ribs 11b1 and 11b2 provided on the duplex guide 11, a transfer receiving member 13R (described below) may be provided on the transfer guide 13. The transfer guide 13 having the transfer receiving member 13R can prevent foreign matter D1 dropped from the duplex guide 11 from adhering to the photosensitive drum 1.

[0116] The following will refer to FIG. 13A to FIG. 16 The configuration of the transfer guide 13 according to the present exemplary embodiment is described.

[0117] Fig.13A and Fig. 13B The transfer guide 13 according to the present exemplary embodiment is shown. Fig. 13B is along Fig.13A 2 is a cross-sectional view of the transfer guide 13 taken along line A in FIG.

[0118] Fig.14A , Fig. 14B , Fig.15A , Fig. 15B and Fig.16 is a cross-sectional view illustrating the transfer guide 13 and the double-sided printing guide 11 according to the present exemplary embodiment. Fig.14A , Fig. 14B , Fig.15A , Fig. 15B and Fig.16 1 is a cross-sectional view showing the double-sided printing guide 11 and the transfer guide 13 according to the present exemplary embodiment, taken in a direction perpendicularly intersecting the rotation axis direction of the photosensitive drum 1 when viewed from the rotation axis of the photosensitive drum 1 .

[0119] According to the present exemplary embodiment, the transfer guide 13 includes a plurality of transfer receiving members 13R. The plurality of transfer receiving members 13R have substantially the same shape.

[0120] like Fig.13A and Fig. 13BAs shown, the transfer guide 13 includes a bottom wall 13a, a first side wall 13b, and a second side wall 13e facing the first side wall 13b. The first side wall 13b and the second side wall 13e extend along the rotation axis direction of the photosensitive drum 1 and are connected to the bottom wall 13a.

[0121] The transfer guide 13 further includes a plurality of side walls 13c. Each of the plurality of side walls 13c extends in a direction intersecting the rotation axis direction of the photosensitive drum 1 and is connected to the bottom wall 13a, the first side wall 13b, and the second side wall 13e. The plurality of side walls 13c face each other. One of the plurality of side walls 13c is referred to as a third side wall, and the other is referred to as a fourth side wall.

[0122] like Fig.14A As shown, in a state where the transfer guide 13 is in the closed position, the bottom wall 13a extends in a direction intersecting the vertical direction. According to the present exemplary embodiment, the bottom wall 13a extends in the horizontal direction.

[0123] The bottom wall 13a, the first side wall 13b, the second side wall 13e and the plurality of side walls 13c are integrally formed on the transfer guide 13 to form a transfer receiving member 13R as a concave portion. More specifically, when the transfer guide 13 is in a closed position, the first side wall 13b, the second side wall 13e and the plurality of side walls 13c extend upward from the bottom wall 13a in the vertical direction. As a result, when the transfer guide 13 is in a closed position, the transfer receiving member 13R as a concave portion opens upward relative to the vertical direction. More specifically, the opening (entrance) of the transfer receiving member 13R is located above the bottom wall 13a.

[0124] In a state where the transfer guide 13 is in the closed position, the second side wall 13 e is located between the first side wall 13 b and the photosensitive drum 1 in the horizontal direction, and the height of the second side wall 13 e is lower than that of the first side wall 13 b .

[0125] In the state where the transfer guide 13 is in the closed position, the transfer receiving member 13R is located below the first communication path CP1 and above the photosensitive drum 1 with respect to the vertical direction, and the bottom wall 13a faces the duplex printing guide 11. In the state where the transfer guide 13 is in the closed position, the transfer receiving member 13R is located below the second communication path CP2 with respect to the vertical direction, and the bottom wall 13a faces the second communication path CP2.

[0126] As a result, the foreign matter D1 passing through the second communication path CP2 is received in the transfer receiving member 13R, thereby preventing the foreign matter D1 from being attached to the photosensitive drum 1. In a state where the transfer guide 13 is in the closed position, the transfer receiving member 13R opens upward relative to the vertical direction. This prevents the foreign matter D1 received by the transfer receiving member 13R from moving to the photosensitive drum 1 when the transfer guide 13 is closed.

[0127] like Fig. 14B As shown, when the transfer guide 13 moves from the closed position to the open position, the transfer receiving member 13R moves away from the photosensitive drum 1. This prevents the foreign matter D1 received by the transfer receiving member 13R from adhering to the photosensitive drum 1 when the transfer guide 13 is opened.

[0128] The transfer receiving member 13R may be disposed below the receiving ribs 11b1 and 11b2 of the double-sided printing guide 11. Fig.15A and Fig. 15B As shown, the transfer receiving member 13R disposed at the end of the transfer guide 13 relative to the rotation axis direction of the photosensitive drum 1 is disposed below the receiving rib 11b2. The transfer receiving member 13R may also be disposed below the receiving rib 11b1. More specifically, the position of the transfer receiving member 13R may overlap the position of the top surface of the receiving ribs 11b1 and 11b2 relative to the rotation axis direction of the photosensitive drum 1. This also enables the transfer receiving member 13R to receive the foreign matter D1 dropped from the receiving ribs 11b1 and 11b2.

[0129] The receiving ribs 11b1 and 11b2 are not provided above the transfer receiving member 13R provided at the center of the transfer guide 13 with respect to the rotation axis direction of the photosensitive drum 1. More specifically, the position of the transfer receiving member 13R with respect to the rotation axis direction of the photosensitive drum 1 may not overlap with the position of the top surface of the receiving ribs 11b1 and 11b2.

[0130] like Fig. 13B and Fig.16 As shown, the transfer guide 13 includes an upper wall 13d protruding from the first side wall 13b. When the transfer guide 13 is in the closed position, the upper wall 13d extends in a direction intersecting the vertical direction, more specifically, extends from the first side wall 13b in a direction away from the second opening 16. According to the present exemplary embodiment, when the transfer guide 13 is in the closed position, the upper wall 13d extends in the horizontal direction. When the transfer guide 13 moves from the closed position to the open position, the upper wall 13d moves away from the photosensitive drum 1.

[0131] The upper wall 13d prevents foreign matter D1 from adhering to the photosensitive drum 1 through the second communication path CP2. The position of the upper wall 13d may overlap the position of the top surfaces of the receiving ribs 11b1 and 11b2 with respect to the rotation axis direction of the photosensitive drum 1.

[0132] like Fig. 13B As shown, a concavo-convex surface profile including a plurality of concave portions is provided at the front end of the upper wall 13d. When the transfer guide 13 is in the closed position, the second rib 11a2 of the duplex guide 11 is received in the plurality of concave portions of the upper wall 13d.

[0133] According to the present exemplary embodiment, the upper wall 13d and the transfer receiving member 13R are closer to the upper end of the transfer guide 13 than to the rotation center 131 of the transfer guide 13. The upper wall 13d and the transfer receiving member 13R are closer to the first communication path CP1 than to the transport path SP1. Therefore, the foreign matter D1 can be received upstream of the second communication path CP2.

[0134] In addition to the duplex printing guide 11 whose evaluation results are shown in Table 1, the transfer guide 13 having the transfer receiving member 13R and the upper wall 13d was used to evaluate the attachment of foreign matter D1 to the photosensitive drum 1. In this evaluation, as in the evaluation of the results shown in Table 1, 0.5 g of mineral powder simulating dust was used.

[0135] Table 2 shows a configuration B including the double-sided printing guide 11 and the transfer guide 13 according to the present exemplary embodiment and Fig. 8A and Figure 8B The evaluation results of the comparative examples are shown.

[0136] Table 2

[0137] First evaluation Second evaluation The third evaluation Comparative Example 60 72 55 Structure B 23 25 20

[0138] Referring to Table 2, the duplex guide 11 and the transfer guide 13 according to the present exemplary embodiment reduce the amount of mineral powder particles to about 60% of that according to the comparative example, thereby preventing foreign matter D1 on the duplex guide 11 from being attached to the photosensitive drum 1 .

[0139] As described above, the present disclosure can prevent the foreign matter D1 from being attached to the photosensitive drum 1. The receiving ribs 11b1 and 11b2, the transfer receiving member 13R, and the upper wall 13d of the double-sided printing guide 11 have the function of preventing the foreign matter D1 from being attached to the photosensitive drum 1. Therefore, if the image forming apparatus 100 is provided with at least any one of the receiving ribs 11b1 and 11b2, the transfer receiving member 13R, and the upper wall 13d, the foreign matter D1 can be prevented from being attached to the photosensitive drum 1. This means that the image forming apparatus 100 does not need to be provided with all of the receiving ribs 11b1 and 11b2, the transfer receiving member 13R, and the upper wall 13d.

[0140] (Variation Example)

[0141] The image forming apparatus 100 according to the present exemplary embodiment adopts a cleaner-less method that does not use a cleaning member for cleaning the photosensitive drum 1. However, the present disclosure is also applicable to an image forming apparatus having a cleaning member for cleaning the photosensitive drum 1.

[0142] The image forming apparatus 100 according to the present exemplary embodiment uses a laser scanning unit as the exposure device 3. However, the present disclosure can also be applied to an image forming apparatus that exposes the photosensitive drum 1 by using a light emitting diode (LED).

[0143] The image forming apparatus 100 according to the present exemplary embodiment is capable of performing duplex printing on the recording medium P. More specifically, the first communication path CP1 is a part of the duplex transport path SP2. The present disclosure is also applicable to the image forming apparatus 100 that does not perform duplex printing on the recording medium P. More specifically, the first communication path CP1 does not need to be a part of the duplex transport path SP2, and the first rib 11a1 and the second rib 11a2 do not need to be used as guide ribs for guiding the recording medium P.

[0144] Although the image forming apparatus 100 according to the present exemplary embodiment is a monochrome printer, the present disclosure can also be applied to a color printer.

[0145] The present disclosure can prevent foreign matter from being attached to a photosensitive drum.

[0146] 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 following claims is to be accorded the broadest interpretation so as to encompass all modifications and equivalent structures and functions.

Claims

1. An imaging device for forming an image on a recording medium, the imaging device comprising: an apparatus body including a discharge portion and a wall disposed on an opposite side of the discharge portion with respect to a horizontal direction, wherein the discharge portion includes a first opening for discharging a recording medium, and the wall includes a second opening; a photosensitive drum housed in the apparatus body, wherein the photosensitive drum is rotatable and disposed below the first opening and the second opening relative to the vertical direction; an exposed surface housed in the device body, wherein the exposed surface is exposed toward a first communication path communicating with the first opening and the second opening, and is arranged below the first communication path; a plurality of ribs arranged along a rotation axis direction of the photosensitive drum, wherein the plurality of ribs protrude from the exposed surface toward the first communication path and each of the plurality of ribs extends in a direction intersecting the rotation axis direction; and a receiving surface protruding from the exposed surface toward the first communication path, wherein the receiving surface faces upward relative to the vertical direction and faces the first communicating path, and the receiving surface extends along the rotation axis direction in a manner connected to the plurality of ribs and is arranged to be located above the photosensitive drum relative to the vertical direction, and The receiving surface is inclined relative to the vertical direction and the horizontal direction, so that the front end of the receiving surface is arranged above the root of the receiving surface connected to the exposed surface.

2. The image forming apparatus according to claim 1, further comprising a fixing unit configured to heat the recording medium, in, The second communication path is formed above the photosensitive drum and below the first communication path with respect to the vertical direction, and The second communication path communicates with a transport path through which the recording medium is transported from the photosensitive drum toward the fixing unit, and communicates with the first communication path.

3. The imaging device according to claim 2, wherein: The receiving surface is located above the second communication path.

4. The imaging device according to claim 2, further comprising: an opposing member facing the first communication path and including the exposed surface, the plurality of ribs, and the receiving surface; and an opening and closing member movable between a closed position for covering the photosensitive drum and an open position for exposing the photosensitive drum, Here, when the opening and closing member is located below the opposing member and is in a closed position, the second communication path is formed between the opening and closing member and the opposing member.

5. The image forming apparatus according to claim 4, further comprising a transfer member facing the photosensitive drum, in, The opening and closing member supports the transfer member, When the opening and closing member is in the closed position, the transfer member contacts the photosensitive drum, and When the opening and closing member is in the open position, the transfer member is separated from the photosensitive drum.

6. The imaging device according to claim 1, in, The exposed surface includes a curved surface, wherein the curved surface is curved upward relative to the vertical direction and includes a first surface, and Wherein, when viewed in the rotation axis direction, the first surface is located on one side of the apex of the curved surface in the horizontal direction, extends downward from the apex, and is located between the apex and the front end of the receiving surface in the horizontal direction.

7. The imaging device according to claim 6, wherein: The first surface includes a curved portion.

8. The imaging device according to claim 6, wherein: The first surface is closer to the second opening than the vertex.

9. The imaging device according to claim 6, wherein: The curved surface includes a second surface which is located on the other side of the apex of the curved surface in the horizontal direction when viewed in the rotation axis direction and which is inclined downward from the apex.

10. The imaging device according to claim 1, wherein The first communication path is a conveying path through which a recording medium may pass, and the plurality of ribs are configured to guide the recording medium.

11. The imaging device according to claim 1, wherein With respect to the rotation axis direction, the position of the receiving surface overlaps with the position of the photosensitive drum.

12. An imaging device for forming an image on a recording medium, the imaging device comprising: an apparatus body including a discharge portion and a wall disposed on an opposite side of the discharge portion with respect to a horizontal direction, wherein the discharge portion includes a first opening for discharging a recording medium, and the wall includes a second opening; a photosensitive drum housed in the apparatus body, wherein the photosensitive drum is rotatable and disposed below the first opening and the second opening relative to the vertical direction; an opposing member housed in the device body, wherein the opposing member faces a first communication path communicating with the first opening and the second opening and is arranged below the first communication path; and The opening and closing member is arranged below the relative member, wherein the opening and closing member is movable between a closed position for covering the photosensitive drum and an open position for exposing the photosensitive drum, The opening and closing member includes a bottom wall, a first side wall, a second side wall, a third side wall and a fourth side wall. The first side wall extends along the rotation axis direction of the photosensitive drum and is connected to the bottom wall. The second side wall extends along the direction of the rotation axis, is connected to the bottom wall, and faces the first side wall. The third side wall extends along a first direction intersecting the direction of the rotation axis and is connected to the bottom wall, the first side wall and the second side wall. The fourth side wall extends along a second direction intersecting the direction of the rotation axis, is connected to the bottom wall, the first side wall and the second side wall, and faces the third side wall. wherein, when the opening and closing member is in the closed position, the bottom wall extends in a direction intersecting the vertical direction, and the first side wall, the second side wall, the third side wall and the fourth side wall extend upward from the bottom wall relative to the vertical direction to form a recessed portion opening upward relative to the vertical direction, The first side wall, the second side wall, the third side wall, the fourth side wall and the bottom wall are integrally arranged to form a recessed portion opening upward, and When the opening and closing member is in the closed position, the upwardly open recess is located below the first communication path communicating with the first opening and the second opening and above the photosensitive drum relative to the vertical direction, and the bottom wall faces the opposing member.

13. The image forming apparatus according to claim 12, further comprising a fixing unit configured to heat the recording medium, in, The second communication path is formed above the photosensitive drum and below the first communication path with respect to the vertical direction, and The second communication path communicates with a transport path through which the recording medium is transported from the photosensitive drum toward the fixing unit, and communicates with the first communication path.

14. The imaging device according to claim 13, wherein In a state where the opening and closing member is in the closed position, the bottom wall faces the second communication path.

15. The imaging device according to claim 12, wherein: When the opening and closing member moves from the closed position to the open position, the upwardly opening recess moves away from the photosensitive drum.

16. The imaging device according to claim 12, wherein: In a state where the opening and closing member is in the closed position, the second side wall is located between the first side wall and the photosensitive drum in the horizontal direction, and the height of the second side wall is lower than that of the first side wall.

17. The image forming apparatus according to claim 12, further comprising a transfer member facing the photosensitive drum, in, The opening and closing member supports the transfer member, When the opening and closing member is in the closed position, the transfer member contacts the photosensitive drum, and When the opening and closing member is in the open position, the transfer member is separated from the photosensitive drum.

18. The imaging device according to claim 12, wherein: In a state where the shutter member is in the closed position, an upper end of the shutter member is located above the photosensitive drum with respect to the vertical direction.

19. The imaging device according to any one of claims 12 to 18, wherein: The device body includes: a housing having the discharge portion; and a door including a wall and capable of opening and closing relative to the housing.

20. An imaging device for forming an image on a recording medium, the imaging device comprising: an apparatus body including a discharge portion and a wall disposed on an opposite side of the discharge portion with respect to a horizontal direction, wherein the discharge portion includes a first opening for discharging a recording medium, and the wall includes a second opening; a photosensitive drum housed in the apparatus body, wherein the photosensitive drum is rotatable and disposed below the first opening and the second opening relative to the vertical direction; an exposed surface housed in the device body, wherein the exposed surface is exposed toward a first communication path communicating with the first opening and the second opening, and is arranged below the first communication path; a plurality of ribs arranged along a rotation axis direction of the photosensitive drum, wherein the plurality of ribs protrude from the exposed surface toward the first communication path and each of the plurality of ribs extends in a direction intersecting the rotation axis direction; and a plurality of receiving members, each of which is a receiving surface that projects from the exposed surface toward the first communicating path and faces upward with respect to the vertical direction to face the first communicating path, wherein the receiving surface extends along the rotation axis direction in a manner connected to the plurality of ribs and is arranged to be located above the photosensitive drum with respect to the vertical direction, wherein the length of the plurality of receiving members relative to the direction of the rotation axis is more than 50% of the length of the imaging area on the photosensitive drum, and Wherein, when viewed in the direction of the rotation axis, the plurality of receiving members are closer to the second opening than to the first opening.

Images