Image forming apparatus

Abstract

To prevent attachment of a foreign substance to a photoconductor drum.SOLUTION: An image forming apparatus forming an image on a recording material has: (i) an apparatus body that includes an ejection part provided with a first opening for ejecting the recording material, and a wall provided on the opposite side of the ejection part with respect to the horizontal direction and provided with a second opening; (ii) a rotatable photoconductor drum that is arranged below the first opening and the second opening with respect to the vertical direction; and (iii) an exposed surface that is exposed toward a first communication path communicating between the first opening and the second opening. The image forming apparatus includes a receiving surface that projects from the exposed surface toward the first communication path and is directed upward in the vertical direction.SELECTED DRAWING: Figure 11

Description

[Technical field]

[0001] The present invention relates to an image forming apparatus, such as a copying machine or a printer, that utilizes an electrophotographic system. [Background technology]

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

[0003] Patent Document 1 discloses an image forming apparatus using a cleanerless system (simultaneous cleaning during development) in which residual toner remaining on a photosensitive drum after transfer is collected by a developing device and reused. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2001-183905 A Summary of the Invention [Problem to be solved by the invention]

[0005] The main body of the image forming apparatus may be provided with an opening for releasing heat and steam generated in the fixing unit to the outside of the main body. When foreign matter such as sand and dust enters the inside of the main body of the apparatus through the opening of the main body of the apparatus, it is preferable to suppress adhesion of the foreign matter to the photosensitive drum. In particular, an image forming apparatus using a cleanerless system such as that disclosed in Patent Document 1 does not have a cleaning member for cleaning toner remaining on the photosensitive drum. Therefore, it is more preferable to suppress adhesion of foreign matter to the photosensitive drum.

[0006] An object of the present invention is to suppress adhesion of foreign matter to a photosensitive drum. [Means for solving the problem]

[0007] One of the inventions related to this application is as follows.

[0008] An image forming apparatus for forming an image on a recording material, an apparatus body including a discharge section provided with a first opening for discharging the recording material, and a wall provided with a second opening, the wall being disposed on the opposite side of the discharge section in a horizontal direction; a rotatable photosensitive drum that is accommodated in the device body and is disposed below the first opening and the second opening in a vertical direction; an exposed surface that is housed in the device body and exposed toward a first communication passage that communicates with the first opening and the second opening, the exposed surface being disposed below the first communication passage; a plurality of ribs arranged in a rotational axis direction of the photosensitive drum protruding from the exposed surface toward the first communication passage, the plurality of ribs each extending in a direction intersecting the rotational axis direction; a receiving surface that protrudes from the exposed surface toward the first communication passage, faces upward in the vertical direction, and faces the first communication passage, the receiving surface extending in the rotation axis direction so as to be connected to the plurality of ribs, and is disposed so as to be located above the photosensitive drum in the vertical direction; having An image forming apparatus, characterized in that the receiving surface is inclined with respect to the vertical direction and the horizontal direction so that a tip of the receiving surface is located above a base of the receiving surface that is connected to the exposed surface.

[0009] One of the inventions related to this application is as follows.

[0010] An image forming apparatus for forming an image on a recording material, an apparatus body including a discharge section provided with a first opening for discharging the recording material, and a wall provided with a second opening, the wall being disposed on the opposite side of the discharge section in a horizontal direction; a rotatable photosensitive drum that is accommodated in the device body and is disposed below the first opening and the second opening in a vertical direction; an exposed surface that is accommodated in the device body, exposed toward a first communication passage that communicates with the first opening and the second opening, and disposed below the first communication passage; a plurality of ribs arranged in a rotational axis direction of the photosensitive drum protruding from the exposed surface toward the first communication passage, the plurality of ribs each extending in a direction intersecting the rotational axis direction; a plurality of receiving portions, each of which is a receiving surface, the receiving surfaces protruding from the exposed surface toward the first communication passage, facing upward in the vertical direction, facing the first communication passage, extending in the rotation axis direction so as to be connected to the plurality of ribs, and disposed so as to be located above the photosensitive drum in the vertical direction; having a length of the plurality of receiving portions in the direction of the rotation axis is 50% or more of a length of an image forming area on the photosensitive drum; an image forming apparatus, wherein the plurality of receiving portions are closer to the second opening than to the first opening when viewed in a direction of the rotation axis;

[0011] One of the inventions related to this application is as follows.

[0012] An image forming apparatus for forming an image on a recording material, an apparatus body including a discharge section provided with a first opening for discharging the recording material, and a wall provided on the opposite side of the discharge section in a horizontal direction and provided with a second opening; a rotatable photosensitive drum that is accommodated in the device body and is disposed below the first opening and the second opening in a vertical direction; an opposing member that is accommodated in the device body, faces a first communication passage that communicates with the first opening and the second opening, and is disposed below the first communication passage; an opening / closing member that is disposed below the opposing member and is movable between a closed position that covers the photosensitive drum and an open position that exposes the photosensitive drum; The opening and closing member is The bottom wall and a first side wall extending along a rotation axis direction of the photosensitive drum and connected to the bottom wall; a second side wall extending along the rotation axis direction, connected to the bottom wall, and facing the first side wall; a third side wall extending along a direction intersecting the rotation axis direction, connected to the bottom wall, the first side wall, and the second side wall; and a fourth side wall extending along a direction intersecting the rotation axis direction, connected to the bottom wall, the first side wall, and the second side wall, and facing the third side wall, when the opening / 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 in the vertical direction from the bottom wall so as to form a recess that is open upward in 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 provided to form the recess, an image forming apparatus characterized in that, when the opening / closing member is in the closed position, the recess is located below a first communication passage that communicates with the first opening and the second opening in the vertical direction and above the photosensitive drum, and the bottom wall faces the opposing member. Effect of the Invention

[0013] According to the present invention, it is possible to suppress adhesion of foreign matter to the photosensitive drum. [Brief description of the drawings]

[0014] [Figure 1] FIG. [Diagram 2] 1A and 1B are schematic cross-sectional views of an image forming apparatus. [Diagram 3] FIG. 1 is a schematic cross-sectional view of an image forming apparatus. [Figure 4] FIG. 1 is a schematic cross-sectional view of an image forming apparatus. [Diagram 5] FIG. 1 is a schematic cross-sectional view of an image forming apparatus. [Figure 6] FIG. 1 is a schematic cross-sectional view of an image forming apparatus. [Figure 7] FIG. 4 is a diagram illustrating toner adhesion to a recording material. [Figure 8]11 is a cross-sectional view illustrating a double-sided guide and a transfer guide according to a comparative example. [Figure 9] 3A and 3B are diagrams showing a double-sided guide and a transfer guide according to the present embodiment. [Figure 10] 3A and 3B are diagrams showing a double-sided guide according to the embodiment. [Figure 11] 3A and 3B are cross-sectional views showing a double-sided guide and a transfer guide according to the embodiment. [Figure 12] 3A and 3B are cross-sectional views showing a double-sided guide and a transfer guide according to the embodiment. [Figure 13] 3A and 3B are diagrams showing a transfer guide according to the embodiment. [Figure 14] 3A and 3B are cross-sectional views showing a double-sided guide and a transfer guide according to the embodiment. [Figure 15] 3A and 3B are cross-sectional views showing a double-sided guide and a transfer guide according to the embodiment. [Figure 16] FIG. 4 is a cross-sectional view showing a double-sided guide and a transfer guide according to the embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] [Example 1] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. However, the dimensions, materials, shapes, and relative positions of the components described in the following embodiments may be changed as appropriate depending on the configuration of the device to which the present invention is applied and various conditions. Therefore, unless otherwise specified, it is not intended to limit the scope of the present invention to only those.

[0016] (Overall configuration of image forming apparatus) The overall configuration of the image forming apparatus 100 will be described with reference to Figs. 1, 2(a), (b), and 3. Fig. 1 is a cross-sectional view of the image forming apparatus 100. Figs. 2(a) and (b) are schematic cross-sectional views of the image forming apparatus 100 for explaining the conveyance of the recording material P. Fig. 3 is a schematic cross-sectional view of the image forming apparatus 100 for explaining the movement of the door 12 and the transfer guide 13. Figs. 1, 2(a), (b), and 3 are views seen in the direction of the rotation axis of a photosensitive drum 1, which will be described later.

[0017] In the following description, the vertical direction when the image forming apparatus 100 is placed on a horizontal surface is defined as the Z direction. The Z direction is opposite to the direction of gravity. The height direction of the image forming apparatus 100 is parallel to the Z direction and opposite to the direction of gravity. The direction perpendicular to the Z direction and parallel to the rotation axis direction (main scanning direction or longitudinal direction) of the photosensitive drum 1 is defined as the X direction. The direction perpendicular to the X direction and the Z direction is defined as the Y direction. The X direction and the Y direction are parallel to the horizontal direction. For convenience, the positive side in the X direction is called the right side and the negative side is called the left side, the positive side in the Y direction is called the front side or front side and the negative side is called the rear side or back side, and the positive side in the Z direction is called the upper side and the negative side is called the lower side.

[0018] The image forming apparatus 100 forms an image on a recording material (sheet) P. The image forming apparatus 100 of this embodiment is a monochrome laser beam printer that employs a cleanerless system.

[0019] The image forming apparatus 100 has an apparatus main body 100a. The apparatus main body 100a houses an image forming unit IM, an exposure device 3, a fixing unit 9, a double-sided guide (opposing member) 11, and a transfer guide (opening / closing member) 13. More specifically, the apparatus main body 100a has a housing 100c and a door 12 that can be opened and closed relative to the housing 100c. The image forming unit IM, the exposure device 3, the fixing unit 9, the double-sided guide 11, and the transfer guide 13 are housed in the housing 100c. The apparatus main body 100a is provided with a control unit (controller) that performs an image forming operation based on image information received from an external device.

[0020] The apparatus main body 100a includes a discharge section 14 having a first opening 14a for discharging the recording material P, and a wall 16a having a second opening 16 provided on the opposite side of the discharge section 14 in the horizontal direction. The wall 16a having the second opening 16 is a part of the door 12. The discharge section 14 is provided in a housing 100c, and includes a pair of discharge rollers 14b.

[0021] The image forming unit IM has a cylindrical electrophotographic photosensitive member (hereinafter, photosensitive drum) 1 as an image carrier, a charging roller 2 as a charging member, and a developing device 4 as a developing means. The photosensitive drum 1 is rotatable around a rotation axis. The direction of the rotation axis of the photosensitive drum 1 is parallel to the X direction.

[0022] The device main body 100a is formed with a first communication passage CP1 that communicates with the first opening 14a and the second opening 16. The photosensitive drum 1 is accommodated in the device main body 100a, and is disposed below the first opening 14a, the second opening 16, and the first communication passage CP1 in the Z direction.

[0023] Around the photosensitive drum 1, there are arranged a charging roller 2, a developing device 4, an exposure device 3 which is an exposure means, a transfer roller 5 which is a transfer means, and a pre-exposure device 6. The exposure device 3, the transfer roller 5, and the pre-exposure device 6 can be called a part of the image forming unit IM.

[0024] Based on image information from an external device, the control unit starts an image forming operation. When the image forming operation starts, the photosensitive drum 1 rotates in the direction of the arrow R1 as shown in FIG. 2(a). The surface of the photosensitive drum 1 is charged to a predetermined potential with a predetermined polarity (negative polarity in this embodiment) by a charging roller 2 that contacts the photosensitive drum 1. The charged surface of the photosensitive drum 1 is exposed by an exposure means 3 in accordance with the image information. As a result, 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 development position and visualized as a toner image.

[0025] The charging roller 2 has an elastic layer made of a conductive elastic body, and the surface roughness of the elastic layer is Ra1.5 to 2.5 μm. The charging roller 2 is in contact with the surface of the photosensitive drum 1 with a predetermined pressure contact force. The position where the charging roller 2 and the photosensitive drum 1 are in contact is called a charging portion. The charging roller 2 is driven by a driving mechanism (not shown) so that the peripheral speed of the charging roller 2 is 105% of the peripheral speed of the photosensitive drum 1. A predetermined DC voltage is applied to the shaft of the charging roller 2 from a charging voltage power source. In this embodiment, a DC voltage of −1350 V is applied to the shaft of the charging roller 2 as the charging voltage. The surface of the photosensitive drum 1 charged by the charging roller 2 has a predetermined potential (dark potential) of −780 V.

[0026] The exposure device 3 is a laser scanner device that irradiates the photosensitive drum 1 with laser light based on image information to form an electrostatic latent image on the surface of the photosensitive drum 1. In this embodiment, the surface of the photosensitive drum 1 has a predetermined potential (light area potential) of -100 V in the portion exposed by the exposure device 3. In this embodiment, toner is supplied from the developing device 4 to the surface of the photosensitive drum 1 having the light area potential, and toner from the developing device 4 is not supplied to the surface of the photosensitive drum 1 having the dark area potential.

[0027] The developing device 4 has a developing roller 41 as a developer carrier, a toner supply roller 42 as a developer supplying means, a developer storage chamber 43 that stores toner, and a developing blade 44 as a layer regulating member. The developing device 4 has a toner transporting member that transports the toner stored in the developer storage chamber 43 toward the toner supply roller 42. The toner supplied from the developer storage chamber 43 is supplied to the developing roller 41 by the toner supply roller 42. The developing blade 44 abuts against the developing roller 41. As 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 (positive expected polarity), and a toner layer of a predetermined thickness is formed on the surface of the developing roller 41.

[0028] The toner is a non-magnetic single-component toner having negative polarity produced by a suspension polymerization method, has a volume average particle size of 6.0 μm, and has a normal charge polarity of negative polarity.

[0029] The developing roller 41 is in contact with the surface of the photosensitive drum 1 with a predetermined pressure. The portion where the developing roller 41 and the photosensitive drum 1 are in contact is hereinafter referred to as the developing portion. The developing roller 41 is driven by a drive mechanism (not shown) so that the peripheral speed of the developing roller 41 is 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 from a developing voltage power supply. During image formation, the toner carried on the developing roller 41 is developed into the portion of the photosensitive drum 1 having the light area potential by electrostatic force generated by the potential difference between this developing voltage of -380V and the light area potential of the photosensitive drum 1 of -100V.

[0030] An area on the surface of the photosensitive drum 1 to which toner can be supplied from the developing roller 41 can be called an image forming area for the photosensitive drum 1. The image forming area for the photosensitive drum 1 may be an area that can be exposed by the exposure device 3, or may be an area corresponding to an area on the surface of the developing roller 41 that is covered with toner (toner coated area).

[0031] The transfer roller 5 faces the photosensitive drum 1 and contacts the surface of the photosensitive drum 1 with a predetermined pressure. A transfer portion is formed between the transfer roller 5 and the photosensitive drum 1. A predetermined voltage is applied to the shaft of the transfer roller 5 from a transfer voltage power source at a predetermined timing, and the toner image formed on the surface of the photosensitive drum 1 is transferred to a recording material P in the transfer portion.

[0032] The pre-exposure device 6 exposes the surface of the photosensitive drum 1 after it has passed the transfer section and before it reaches the charging section. This eliminates unevenness in the surface potential of the photosensitive drum 1. Furthermore, the toner remaining on the photosensitive drum 1 without being transferred to the recording material P passes through the charging section and is collected by the developing roller 41.

[0033] Meanwhile, a tray 10 serving as a recording material storage section (sheet storage section) for storing recording material P, and a paper feed unit 7 are provided in the lower portion of the image forming apparatus 100. The paper feed unit 7 has a pickup roller 7a, a feed roller 7b, and a separation roller 7c.

[0034] The pickup roller 7a rotates in contact with the topmost recording material P stacked on the tray 10, and sends out the recording material P from the tray 10. The recording materials P sent out from the tray 10 are further conveyed in a state where they are separated one by one at a nip portion (separation nip) between the feed roller 7b and the separation roller 7c.

[0035] The apparatus main body 100a has a conveying section 8 including 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 material P that has passed through the separation nip is conveyed toward the transfer section by the conveying roller 8a and the first driven roller 8b that is in contact with the conveying roller 8a.

[0036] In synchronization with the timing at which the toner image formed on the photosensitive drum 1 reaches the transfer section, a recording material P stored in a tray 10 is conveyed to the transfer section by a paper feed unit 7 and a conveying roller 8. The toner image formed on the photosensitive drum 1 is transferred onto the recording material P by a transfer roller 5 to which a predetermined transfer voltage is applied by a transfer voltage power supply.

[0037] A fixing unit 9 configured to heat the recording material P is provided above the photosensitive drum 1. The fixing unit 9 has a heating roller with a built-in heater and a pressure roller that is biased toward the heating roller with a predetermined pressure. A transport path SP1 is formed downstream of the transfer unit and upstream of the fixing unit in the transport direction of the recording material P. The recording material P that passes through the transfer unit and is transported from the photosensitive drum 1 toward the fixing unit 9 passes through the transport path SP1.

[0038] Here, a second communication passage CP2 is formed above the photosensitive drum 1 and below the first communication passage CP1. The second communication passage CP2 communicates with the transport path SP1 and the first communication passage CP1.

[0039] The recording material P conveyed to the fixing unit 9 is heated and pressurized by the fixing unit 9, so that the toner image transferred onto the recording material P is fixed onto the recording material P.

[0040] The recording material P on which the toner image has been fixed is discharged from the first opening 14a to the outside of the apparatus main body 100a. The apparatus main body 100a is provided with a paper discharge tray 15 on which the recording material P is stacked. The recording material P discharged from the first opening 14a is stacked on the paper discharge tray 15.

[0041] When the recording material P is heated, water vapor may be generated from the recording material P. The water vapor generated from the recording material P is discharged to the outside of the apparatus main body 100a through the second opening (exhaust port) 16. In this embodiment, the apparatus main body 100a (housing 100c) has an upper opening 100d above the first communication passage CP1. The upper opening 100d includes a plurality of holes, and water vapor is also discharged to the outside of the apparatus main body 100a through the upper opening 100d.

[0042] In this embodiment, the image forming apparatus 100 is capable of single-sided printing, in which an image is formed on one side of the recording material P, and double-sided printing, in which an image is formed on both sides of the recording material P.

[0043] When single-sided printing is performed, as shown in Fig. 2(a), the recording material P is transported in the P1 direction by the discharge roller pair 14b and discharged onto the paper discharge tray 15. When double-sided printing is performed, the recording material P with a toner image fixed on one side is transported in the arrow P1 direction by the discharge roller pair 14b, and then the rotation direction of the discharge roller pair 14b is reversed, and the recording material P is transported in the P2 direction as shown in Fig. 2(b).

[0044] The recording material P conveyed in the P2 direction passes through the double-sided conveying path SP2, and is conveyed by the second driven roller 8c and the conveying roller 8a to the nip portion between the first driven roller 8b and the conveying roller 8a. After that, the recording material P, on whose back side a toner image has been formed in the transfer section, passes through the fixing section 9 and is discharged onto the paper discharge tray 15.

[0045] In this embodiment, the first communication path CP1 is a part of the double-sided conveying path SP2. The double-sided guide 11 and the transfer guide 13 function as guide members that guide the recording material P passing through the double-sided conveying path P2.

[0046] The toner in the developing device 4 is reduced by the image forming operation on the recording material P. The image forming apparatus 100 of this embodiment can replenish toner to the developing device 4 from a replenishing container TP that is detachably attached to the image forming apparatus 100. As shown in FIG. 1, a replenishing receiver 100R is provided in an apparatus main body 100a of the image forming apparatus 100. A replenishing container TP is detachably attached to the replenishing receiver 100R. Toner is replenished from the replenishing container TP attached to the replenishing receiver 100R to the developing device 4 through a toner flow path (not shown).

[0047] In this embodiment, the discharge tray 15 has a function as a cover that covers the supply receiving portion 100R in an openable and closable manner. The discharge tray 15 can be moved to a cover position that covers the supply receiving portion 100R and a supply position that exposes the supply receiving portion 100R. The discharge tray 15 can rotate around the rotation center 15a relative to the housing portion 100c. When the recording material P discharged from the first opening 14a is loaded onto the discharge tray 15, the discharge tray 15 is positioned at the cover position. When the discharge tray 15 moves from the cover position to the supply position, the discharge tray 15 moves in a direction approaching the first opening 14a. When the discharge tray 15 is in the supply position, the first opening 14a is covered by the discharge tray 15, so that the discharge of the recording material P from the first opening 14a and the image forming operation on the recording material P are restricted.

[0048] When a so-called jam occurs in which a recording material P is stuck in the image forming apparatus 100, a so-called jam clearance is performed in which the user removes the recording material P from inside the image forming apparatus 100. For this reason, the door 12 and the transfer guide 13 of the image forming apparatus 100 of this embodiment are each configured to be openable and closable. The door 12 is rotatable about a rotation center 121, and the transfer guide 13 is rotatable about a rotation center 131 (see FIG. 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 below the photosensitive drum 1 in the vertical direction.

[0049] The transfer guide 13 is an opening / closing member that can move between a closed position where the photosensitive drum 1 is covered and an open position where the photosensitive drum 1 is exposed. When the transfer guide 13 is in the closed position, the upper end of the transfer guide 13 is located above the photosensitive drum 1 in the vertical direction. The transfer guide 13 supports a transfer roller 5, and when the transfer guide 13 is in the closed position, the transfer roller 5 abuts against the photosensitive drum 1, and 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 may be opened and closed in conjunction with the opening and closing operation of the door 12.

[0050] When the recording material P is stuck between the conveying section 8 and the fixing device 9, the user opens the door 12 and moves the transfer guide 13 to the open position as shown in Fig. 3. In this state, the user can remove the recording material P and clear the jam. On the other hand, when the recording material P is stuck in the double-sided conveying path SP2, the user can also clear the jam by opening only the door 12.

[0051] After the jam clearance is completed, the transfer guide 13 is moved to the closed position and the door 12 is closed, whereby the image forming apparatus 100 is ready to resume the image forming operation.

[0052] <Intrusion of dust and other foreign matter> 4, 5, and 6, the second opening 16 and the intrusion of foreign matter such as sand and dust into the inside of the image forming apparatus 100 will be described.

[0053] As described above, the device body 100a includes a wall 16a provided with the second opening 16, which is provided on the opposite side of the discharge section 14 in the horizontal direction (see FIG. 1). The wall 16a is a part of the door 12. As shown in FIG. 4, the second opening 16 includes a plurality of holes, and communicates between the inside of the device body 100a (the first communication path CP1, the double-sided conveying path SP2) and the outside of the device body 100a.

[0054] The second opening 16 is located above the photosensitive drum 1 and the fixing unit 9 (more specifically, the fixing nip) in the vertical direction. In addition, in the direction of the rotation axis of the photosensitive drum 1, a range in which an image forming area for the photosensitive drum 1 exists and a range in which the second opening 16 exists overlap with each other.

[0055] A first communication passage CP1 communicating with the first opening 14a and the second opening 16 serves as a passage for air. More specifically, as shown by an arrow A1 in Fig. 5, air may pass from the first opening 14a to the second opening 16. Also, in the opposite direction to the arrow A1 in Fig. 5, air may pass from the second opening 16 to the first opening 14a. These air flows may be generated by an air conditioning system or a blower system in the room in which the image forming apparatus 100 is installed.

[0056] The double-sided guide 11 is located below the first communication passage CP in the vertical direction and faces the first communication passage CP1. When viewed in the direction of the rotation axis of the photosensitive drum 1, the double-sided guide 11 is disposed between the first opening 14a and the second opening 16 in the horizontal direction. In addition, the double-sided guide 11 is disposed above the photosensitive drum 1 in the vertical direction. When viewed in the direction of the rotation axis 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.

[0057] Here, when there is a large amount of foreign matter D1 such as sand and dust in the air and the air flow passing through the first communication passage CP1 is strong, the foreign matter D1 such as sand and dust may enter the image forming apparatus 100 together with the air passing through the first communication passage CP1 and accumulate on the double-sided guide 11. Note that the foreign matter D1 in this case may include foreign matter D1 that has entered together with the air flowing in the direction of the arrow A1 in Fig. 5, and may also include foreign matter D1 that has entered together with the air flowing in the opposite direction to the direction of the arrow A1.

[0058] For example, vibrations generated when closing the door 12 or the transfer guide 13 may cause foreign matter D1 accumulated on the double-sided guide 11 to fall from the double-sided guide 11 to the negative Z-direction. In this embodiment, the transfer guide 13 is biased by a spring, and therefore tends to vibrate more strongly than the door 12 when closed.

[0059] In a configuration in which the photosensitive drum 1 is disposed below the double-sided guide 11, there is a possibility that a foreign object D1 may fall near the photosensitive drum 1.

[0060] For example, in this embodiment, as shown in Figures 1 and 6, the transfer guide 13 is located below the double-sided guide 11, and when the transfer guide 13 is in the closed position, a second communication passage CP2 is formed between the transfer guide 13 and the double-sided guide 11. The second communication passage CP2 communicates with the transport path SP1 and the first communication passage CP1. As shown in Figure 6, the foreign object D1 may fall near the photosensitive drum 1 through the second communication passage CP2.

[0061] Furthermore, when the transfer guide 13 is in the open position, the photosensitive drum 1 is exposed. When the transfer guide 13 is moved from the open position to the closed position, a foreign object D1 may fall near the photosensitive drum 1.

[0062] 7 is a diagram for explaining toner adhesion to the recording material P. For example, when the photosensitive drum 1 is scratched to a predetermined depth or more, the charge retention ability of the surface of the photosensitive drum 1 decreases. As a result, toner may be supplied from the developing roller 41 to the scratched portion (the portion of the surface of the photosensitive drum 1 where the charge retention ability has decreased) and may periodically adhere to the recording material P. In the example shown in FIG. 7, toner adhesion is repeated in one rotation period of the photosensitive drum 1.

[0063] In this way, when the image forming apparatus 100 is used in an environment where there is a large amount of foreign matter D1 such as sand and dust in the air and the air flow through the first communication passage CP1 is strong, if toner adhesion occurs due to the foreign matter D1 adhering to the photosensitive drum 1, it is necessary to replace the photosensitive drum 1.

[0064] <Configuration for preventing adhesion of foreign matter to photosensitive drum> 8 is a cross-sectional view for explaining a double-sided guide 11' and a transfer guide 13' according to a comparative example. In Fig. 8(a), the transfer guide 13' is positioned in an open position, and in Fig. 8(b), the transfer guide 13' is positioned in a closed position. The double-sided guide 11' according to the comparative example does not have a portion for suppressing the falling of the foreign matter D1, and the foreign matter D1 accumulated on the double-sided guide 11' falls near the photosensitive drum 1.

[0065] A configuration for suppressing adhesion of a foreign matter D1 to the photosensitive drum 1 will be described with reference to FIGS.

[0066] Figures 9(a) and (b) are diagrams showing the double-sided guide 11 and the transfer guide 13 according to this embodiment. In Figure 9(a), the transfer guide 13 is in a closed position, and in Figure 9(b), the transfer guide 13 is in an open position. Figures 9(a) and 9(b) are views of the image forming apparatus 100 as viewed in the Y direction. Arrow 1a in Figure 9(b) indicates the direction of the rotation axis of the photosensitive drum 1.

[0067] 10(a) and (b) are diagrams showing the double-sided guide 11 according to this embodiment. Fig. 10(a) is a diagram showing the double-sided guide 11 in the vertical direction, more specifically, in the direction opposite to the Z direction. Fig. 10(b) is a perspective view of the double-sided guide 11.

[0068] 11(a), (b), 12(a), and (b) are cross-sectional views showing the double-sided guide 11 and the transfer guide 13 according to this embodiment. Figures 11(a), (b), 12(a), and (b) are cross-sectional views of the double-sided guide 11 and the transfer guide 13 according to this embodiment, cut in a direction perpendicular to the rotation axis of the photosensitive drum 1, as viewed in the direction of the rotation axis of the photosensitive drum 1.

[0069] The double-sided guide 11 of this embodiment has receiving ribs (receiving protrusions) 11b1 and 11b2. The receiving ribs 11b1 and 11b2 receive the foreign matter D1 and prevent the foreign matter D1 from adhering to the photosensitive drum 1. The shape of the double-sided guide 11 will be described in more detail below.

[0070] The double-sided guide 11 is housed in the device main body 100A and has an exposed surface 11c exposed toward the first communication passage CP1. The exposed surface 11c is disposed below the first communication passage CP1. The exposed surface 11c being exposed toward the first communication passage CP1 means that the exposed surface 11c is visible from any position in the first communication passage CP1. The exposed surface 11c can also be referred to as an opposing surface that faces the first communication passage CP1.

[0071] As shown in Figures 10(b), 11(a), etc., the exposed surface 11c has a curved surface that curves upward in the vertical direction. The curved surface of the exposed surface 11c includes a vertex 11c0 that is at the highest position in the vertical direction, a first surface 11c1, and a second surface 11c2. As shown in Figure 11(a), when viewed in the direction of the rotation axis of the photosensitive drum 1, the first surface 11c1 is located on one side of the vertex 11c0, and the second surface 11c2 is located on the other side of the vertex 11c0.

[0072] When viewed in the rotation axis direction of the photosensitive drum 1, the vertex 11c0 is located between the first opening 14a and the second opening 16 in the horizontal direction. As can be seen from Fig. 1, when viewed in the rotation axis direction of the photosensitive drum 1, the vertex 11c0 is closer to the second opening 16 than the first opening 14a. In other words, the distance between the vertex 11c0 and the second opening 16 in the horizontal direction is shorter than the distance between the vertex 11c0 and the first opening 14a.

[0073] 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 apex 11c0 in the horizontal direction. That is, the distance between the first surface 11c1 and the second opening 16 is shorter than the distance between the apex 11c0 and the second opening 16 in the horizontal direction. 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 apex 11c0 in the horizontal direction. That is, the distance between the second surface 11c2 and the first opening 14a is shorter than the distance between the apex 11c0 and the first opening 14a in the horizontal direction.

[0074] The first surface 11c1 and the second surface 11c2 are surfaces that are inclined downward from the vertex 11c0. In other words, the first surface 11c1 and the second surface 11c2 each extend downward in the vertical direction as they move away from the vertex 11c0 in the horizontal direction. In this embodiment, the first surface 11c1 and the second surface 11c2 each include a curved surface.

[0075] 10(a) and (b), the double-sided 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 communication passage CP1. The plurality of first ribs 11a1 are arranged discretely from one another and aligned in the direction of the rotation axis of the photosensitive drum 1. The plurality of second ribs 11a2 are aligned in the direction of the rotation axis of the photosensitive drum 1.

[0076] Each of the multiple first ribs 11a1 and each of the multiple second ribs 11a2 extends in a direction intersecting with the rotation axis direction of the photosensitive drum 1. In this embodiment, the first communication path CP1 functions as a transport path through which the recording material P can pass. Specifically, the first communication path CP1 is a part of the double-sided transport path SP2. The multiple first ribs 11a1 and the multiple second ribs 11a2 extend along the transport direction of the recording material P passing through the first communication path CP1, and have the function of guiding the recording material P passing through the first communication path CP1.

[0077] 10(b), the back side of the double-sided guide 11 is provided with receiving ribs 11b1 and 11b2 protruding from the exposed surface 11c of the double-sided guide 11. The upper surfaces (surfaces facing upward in the vertical direction) of the receiving ribs 11b1 and 11b2 function as receiving surfaces for receiving foreign matter D1. In other words, the double-sided guide 11 has a plurality of receiving portions, each of which is the upper surface of the receiving ribs 11b1 and 11b2.

[0078] In this embodiment, the double-sided 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 substantially the same. The number of receiving ribs 11b1 and 11b2 may be one or more. The double-sided guide 11 may have either the receiving rib 11b1 or the receiving rib 11b2.

[0079] The upper surfaces of the receiving ribs 11b1 and 11b2 protrude from the exposed surface 11c toward the first communication passage CP1 and face the first communication passage CP1. At least a portion of the upper surfaces of the receiving ribs 11b1 and 11b2 is located directly below the first communication passage CP1. Therefore, the upper surfaces of the receiving ribs 11b1 and 11b2 can receive the foreign object D1 that has fallen downward from the first communication passage CP1.

[0080] The upper surfaces of the receiving ribs 11b1 and 11b2 extend in the direction of the rotation axis of the photosensitive drum 1 so as to be connected to the second ribs 11a2. This prevents the foreign matter D1 from falling from the upper surfaces of the receiving ribs 11b1 and 11b2.

[0081] The upper surfaces of the receiving ribs 11b1 and 11b2 are positioned vertically above the photosensitive drum 1. The upper surfaces of the receiving ribs 11b1 and 11b2 are positioned vertically above the second communication passage CP2.

[0082] 9(b), in the direction of the rotation axis of the photosensitive drum 1, the positions of the upper surfaces of the receiving ribs 11b1 and 11b2 overlap with the position of the photosensitive drum 1. In the direction of the rotation axis of the photosensitive drum 1, the length of the multiple receiving portions (the total length of the upper surfaces of the receiving ribs 11b1 and 11b2) is preferably 50% or more of the length of the image forming area on the photosensitive drum 1.

[0083] In this embodiment, the receiving ribs 11b1 and 11b2 are provided in a portion other than the longitudinal center of the double-sided guide 11, but they may be provided in a region including the longitudinal center. Even if the receiving ribs 11b1 and 11b2 are arranged so as not to be connected to the second rib 11a2, the falling of the foreign object D1 can be suppressed.

[0084] A space for accommodating foreign matter D1 is formed by the upper surfaces of receiving ribs 11b1 and 11b2, exposed surface 11c, and the multiple second ribs 11a2, thereby preventing foreign matter D1 from falling and adhering to the photosensitive drum 1.

[0085] 12(a) and 12(b), when viewed in the direction of the rotation axis of the photosensitive drum 1, the upper surfaces of the receiving ribs 11b1 and 11b2 are closer to the second opening 16 than the first opening 14a. In other words, the distance between the upper surfaces of the receiving ribs 11b1 and 11b2 and the second opening 16 is shorter than the distance between the upper surfaces of the receiving ribs 11b1 and 11b2 and the first opening 14a. In addition, the upper surfaces of the receiving ribs 11b1 and 11b2 protrude from the exposed surface 11c toward the second opening 16.

[0086] The upper surfaces of the receiving ribs 11b1 and 11b2 may extend horizontally, but preferably extend upward in a direction intersecting the horizontal and vertical directions. More specifically, the upper surfaces of the receiving ribs 11b1 and 11b2 are preferably inclined with respect to the vertical and horizontal directions so that the tips of the upper surfaces of the receiving ribs 11b1 and 11b2 are located above the bases that are connected to the exposed surface 11c.

[0087] Further, the first surface 11c1 of the exposed surface 11c is located between the apex 11c0 and the tips of the upper surfaces of the receiving ribs 11b1 and 11b2 in the horizontal direction when viewed in the rotation axis direction of the photosensitive drum 1. As a result, the foreign matter D1 that has fallen from the first surface 11c1 is received by the upper surfaces of the receiving ribs 11b1 and 11b2.

[0088] Foreign matter D1, which may cause toner adhesion as shown in FIG. 7 when it adheres to the photosensitive drum 1, tends to have a size of about several tens to several hundreds of μm. Therefore, it is preferable that the length by which the upper surfaces of the receiving ribs 11b1 and 11b2 protrude from the exposed surface 11c (hereinafter, simply referred to as the protruding length) is 1 mm or more. In order to prevent the foreign matter D1 from falling from the upper surfaces of the ribs 11b1 and 11b2 when the impact of the opening and closing operation of the transfer guide 13 is strong, it is preferable that the protruding length is long.

[0089] On the other hand, in this embodiment, the second rib 11a2 functions as a guide rib that guides the recording material P. The receiving ribs 11b1 and 11b2 extend from the exposed surface 11c in a direction opposite to the conveying direction of the recording material P. The protruding height is shorter than the length by which the second rib 11a2 protrudes from the exposed surface 11c. As a result, contact between the upper surfaces of the receiving ribs 11b1 and 11b2 and the recording material P is suppressed.

[0090] 12(a) and 12(b), the tips of the upper surfaces of the receiving ribs 11b1 and 11b2 protrude in the -Y direction beyond the rear surface of the transfer guide 13. The tips of the upper surfaces of the receiving ribs 11b1 and 11b2 protrude in the -Y direction beyond the end of the second communication passage CP2 formed by the double-sided guide 11 and the transfer guide 13.

[0091] As a result, even when foreign matter D1 falls from the upper surfaces of receiving ribs 11b1 and 11b2, foreign matter D1 is prevented from entering second communication path CP2, and foreign matter D1 is less likely to fall near photosensitive drum 1. Transfer guide 13 is provided with guide ribs that guide recording material P passing through double-sided conveying path SP2, and the back surface of transfer guide 13 refers to the surface between the guide ribs of transfer guide 13.

[0092] 8, if the receiving rib 11b2 is not present, when a foreign object D1 on the double-sided guide 11 falls due to the vibration of closing the transfer guide 13, it easily gets into the gap between the double-sided guide 11 and the transfer guide 13 and falls onto the photosensitive drum 1. On the other hand, if the receiving ribs 11b1 and 11b2 are present, the upper surfaces of the receiving ribs 11b1 and 11b2 block the gap between the double-sided guide 11 and the transfer guide 13 when viewed from the positive side in the Z direction. The upper surfaces of the receiving ribs 11b1 and 11b2 can receive the foreign object D1 and prevent it from falling onto the photosensitive drum 1.

[0093] The effect of the double-sided guide 11 according to this embodiment will be described. The state of adhesion of foreign matter D1 to the photosensitive drum 1 was compared between a configuration including the double-sided guide 11 of the comparative example shown in FIG. 8 and a configuration including the double-sided guide 11 according to this embodiment. Specifically, 0.5 g of mineral powder simulating sand dust was uniformly scattered on the double-sided guides 11, 11' in the longitudinal direction. The mineral powder contained silica with a particle size of several tens to several hundreds of microns. Next, the transfer guide 13 was opened and closed five times, and the number of mineral powder particles adhering to the photosensitive drum 1 was counted. The evaluation was performed three times for each of the double-sided guide 11 of this embodiment and the comparative example.

[0094] Table 1 shows the evaluation results of the configuration A equipped with the double-sided guide 11 of this embodiment and the comparative example.

[0095] [Table 1]

[0096] As shown in Table 1, the number of mineral powder particles adhering to the double-sided guide 11 of this embodiment was reduced by about half compared to the comparative example, and the effect of suppressing adhesion of foreign matter D1 on the double-sided guide 11 to the photosensitive drum 1 was observed.

[0097] In the present embodiment, the receiving rib 11b1, the receiving rib 11b2, the exposed surface 11c, and the second rib 11a2 are integrally provided on the double-sided guide 11. However, the receiving rib 11b1, the receiving rib 11b2, the exposed surface 11c, and the second rib 11a2 may be separated into a plurality of parts.

[0098] (Transcription Guide) In addition to providing the receiving ribs 11b1 and 11b2 on the double-sided guide 11, the transfer guide 13 may be provided with a transfer receiving portion 13R described below. By providing the transfer guide 13 with the transfer receiving portion 13R, it is possible to prevent the foreign matter D1 that has fallen from the double-sided guide 11 from adhering to the photosensitive drum 1.

[0099] The configuration of the transfer guide 13 according to this embodiment will be described below with reference to FIGS.

[0100] Figures 13(a) and (b) are diagrams showing the transfer guide 13 according to this embodiment. Figure 13(b) is a cross-sectional view of the transfer guide 13 taken along line A in Figure 13(a).

[0101] 14(a), (b), 15(a), (b), and 16 are cross-sectional views showing the double-sided guide 11 and the transfer guide 13 according to this embodiment. 14(a), (b), 15(a), (b), and 16 are cross-sectional views of the double-sided guide 11 and the transfer guide 13 according to this embodiment cut in a direction perpendicular to the rotation axis of the photosensitive drum 1, viewed in the direction of the rotation axis of the photosensitive drum 1.

[0102] In this embodiment, the transfer guide 13 has a plurality of transfer receiving portions 13R. The shapes of the plurality of transfer receiving portions 13R are substantially the same.

[0103] 13(a) and 13(b), the transfer guide 13 has 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.

[0104] Furthermore, the transfer guide 13 has a plurality of side walls 13c. Each of the side walls 13c extends in a direction intersecting with 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 side walls 13c face each other, and one of the side walls 13c can be called a third side wall, and the other can be called a fourth side wall.

[0105] 14A, when the transfer guide 13 is in the closed position, the bottom wall 13a extends in a direction intersecting the vertical direction. In this embodiment, the bottom wall 13a extends in the horizontal direction.

[0106] The bottom wall 13a, the first side wall 13b, the second side wall 13e, and the multiple side walls 13c are integrally provided with the transfer guide 13, and form a transfer receiving portion 13R as a recess. Specifically, when the transfer guide 13 is in the closed position, the first side wall 13b, the second side wall 13e, and the multiple side walls 13c extend vertically upward from the bottom wall 13a. As a result, when the transfer guide 13 is in the closed position, the transfer receiving portion 13R as a recess is opened vertically upward. In other words, the opening that serves as the entrance of the transfer receiving portion 13R is located above the bottom wall 13a.

[0107] When the transfer guide 13 is in the closed position, the second side wall 13e is located between the first side wall 13b and the photosensitive drum 1 in the horizontal direction, and the height of the second side wall 13e is lower than the height of the first side wall 13b.

[0108] When the transfer guide 13 is in the closed position, the transfer receiving portion 13R is located below the first communication passage CP1 in the vertical direction and above the photosensitive drum 1, and the bottom wall 13a faces the double-sided guide 11. When the transfer guide 13 is in the closed position, the transfer receiving portion 13R is located below the second communication passage CP2 in the vertical direction, and the bottom wall 13a faces the second communication passage CP2.

[0109] As a result, the foreign matter D1 passing through the second communication passage CP2 is contained in the transfer receiving portion 13R, which prevents the foreign matter D1 from adhering to the photosensitive drum 1. Since the transfer receiving portion 13R opens upward in the vertical direction when the transfer guide 13 is in the closed position, the foreign matter D1 received by the transfer receiving portion 13R is prevented from moving toward the photosensitive drum 1 when the transfer guide 13 is closed.

[0110] 14B, when the transfer guide 13 moves from the closed position to the open position, the transfer receiving portion 13R moves away from the photosensitive drum 1. This prevents the foreign matter D1 received by the transfer receiving portion 13R from adhering to the photosensitive drum 1 when the transfer guide 13 is opened.

[0111] The transfer receiving portion 13R may be disposed below the receiving ribs 11b1 and 11b2 of the double-sided guide 11. For example, as shown in FIGS. 15(a) and 15(b), the transfer receiving portion 13R disposed at the end of the transfer guide 13 is disposed below the receiving rib 11b2 in the direction of the rotation axis of the photosensitive drum 1. The transfer receiving portion 13R may be disposed below the receiving rib 11b1. That is, the position of the transfer receiving portion 13R and the positions of the upper surfaces of the receiving ribs 11b1 and 11b2 in the direction of the rotation axis of the photosensitive drum 1 may overlap. In this way, the foreign object D1 that has fallen from the receiving ribs 11b1 and 11b2 can also be received by the transfer receiving portion 13R.

[0112] In addition, the receiving ribs 11b1 and 11b2 are not disposed above the transfer receiving portion 13R disposed in the center of the transfer guide 13 with respect to the rotation axis direction of the photosensitive drum 1. In other words, with respect to the rotation axis direction of the photosensitive drum 1, the position of the transfer receiving portion 13R does not have to overlap with the positions of the upper surfaces of the receiving ribs 11b1 and 11b2.

[0113] 13(b) and 16, the transfer guide 13 has 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. In this embodiment, the upper wall 13d extends in the horizontal direction when the transfer guide 13 is in the closed position. 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.

[0114] The upper wall 13d prevents the foreign matter D1 from passing through the second communication passage CP2 and prevents the foreign matter D1 from adhering to the photosensitive drum 1. In the rotational axis direction of the photosensitive drum 1, the position of the upper wall 13d and the positions of the upper surfaces of the receiving ribs 11b1 and 11b2 may overlap with each other.

[0115] 13(b), the tip of the upper wall 13d is provided with a concave-convex shape including a plurality of concave portions. When the transfer guide 13 is in the closed position, the second rib 11a2 of the double-sided guide 11 is housed in the plurality of concave portions of the upper wall 13d.

[0116] In this embodiment, the upper wall 13d and the transfer receiving portion 13R are closer to the upper end of the transfer guide 13 than the rotation center 131 of the transfer guide 13. Also, the upper wall 13d and the transfer receiving portion 13R are closer to the first communication passage CP1 than the transport path SP1. Therefore, the foreign object D1 can be received on the upstream side of the second communication passage CP2.

[0117] In addition to the double-sided guide 11 whose results are shown in Table 1, a transfer guide 13 having a transfer receiving portion 13R and an upper wall 13d was used to evaluate adhesion of foreign matter D1 to the photosensitive drum 1. In this evaluation, 0.5 g of mineral powder simulating sand dust was used, as in the evaluation whose results are shown in Table 1.

[0118] Table 2 shows the evaluation results of the configuration B including the double-sided guide 11 and the transfer guide 13 of this embodiment, and the comparative example shown in FIG.

[0119] [Table 2]

[0120] As shown in Table 2, with the double-sided guide 11 and transfer guide 13 of this embodiment, the number of mineral powder particles adhering was reduced by approximately 60% compared to the comparative example, and the adhesion of foreign matter D1 on the double-sided guide 11 to the photosensitive drum 1 was suppressed.

[0121] As described above, according to the present invention, it is possible to prevent the foreign matter D1 from adhering to the photosensitive drum 1. The receiving ribs 11b1 and 11b2, the transfer receiving portion 13R, and the upper wall 13d of the double-sided guide 11 each have a function of preventing the foreign matter D1 from adhering to the photosensitive drum 1. Therefore, as long as the image forming apparatus 100 has at least one of the receiving ribs 11b1 and 11b2, the transfer receiving portion 13R, and the upper wall 13d, it is possible to prevent the foreign matter D1 from adhering to the photosensitive drum 1. In other words, it is not necessary for the image forming apparatus 100 to have all of the receiving ribs 11b1 and 11b2, the transfer receiving portion 13R, and the upper wall 13d.

[0122] (Modification) The image forming apparatus 100 according to this embodiment adopts a cleanerless system in which no cleaning member is used to clean the photosensitive drum 1, but the present invention can also be applied to an image forming apparatus having a cleaning member to clean the photosensitive drum 1.

[0123] Further, the image forming apparatus 100 according to the present embodiment uses a laser scanner unit as the exposure device 3, but the present invention can also be applied to an image forming apparatus that exposes the photosensitive drum 1 using a light emitting diode.

[0124] In the image forming apparatus 100 according to the present embodiment, double-sided printing of the recording material P was possible. In other words, the first communication path CP1 was part of the double-sided conveying path SP2. The present invention can also be applied to an image forming apparatus 100 that does not perform double-sided printing on the recording material P. In other words, the first communication path CP1 does not have to be part of the double-sided conveying path SP2, and the first rib 11a1 and the second rib 11a2 do not have to function as guide ribs that guide the recording material P.

[0125] Although the image forming apparatus 100 according to this embodiment is a monochrome printer, the present invention can also be applied to a color printer.

[0126] (summary) This embodiment discloses at least the following.

[0127] (Configuration 1) An image forming apparatus for forming an image on a recording material, an apparatus body including a discharge section provided with a first opening for discharging the recording material, and a wall provided with a second opening, the wall being disposed on the opposite side of the discharge section in a horizontal direction; a rotatable photosensitive drum that is accommodated in the device body and is disposed below the first opening and the second opening in a vertical direction; an exposed surface that is housed in the device body and exposed toward a first communication passage that communicates with the first opening and the second opening, the exposed surface being disposed below the first communication passage; a plurality of ribs arranged in a rotational axis direction of the photosensitive drum protruding from the exposed surface toward the first communication passage, the plurality of ribs each extending in a direction intersecting the rotational axis direction; a receiving surface that protrudes from the exposed surface toward the first communication passage, faces upward in the vertical direction, and faces the first communication passage, the receiving surface extending in the rotation axis direction so as to be connected to the plurality of ribs, and is disposed so as to be located above the photosensitive drum in the vertical direction; having An image forming apparatus, characterized in that the receiving surface is inclined with respect to the vertical direction and the horizontal direction so that a tip of the receiving surface is located above a base of the receiving surface that is connected to the exposed surface.

[0128] (Configuration 2) An image forming apparatus for forming an image on a recording material, an apparatus body including a discharge section provided with a first opening for discharging the recording material, and a wall provided with a second opening, the wall being disposed on the opposite side of the discharge section in a horizontal direction; a rotatable photosensitive drum that is accommodated in the device body and is disposed below the first opening and the second opening in a vertical direction; an exposed surface that is accommodated in the device body, exposed toward a first communication passage that communicates with the first opening and the second opening, and disposed below the first communication passage; a plurality of ribs arranged in a rotational axis direction of the photosensitive drum protruding from the exposed surface toward the first communication passage, the plurality of ribs each extending in a direction intersecting the rotational axis direction; a plurality of receiving portions, each of which is a receiving surface, the receiving surfaces protruding from the exposed surface toward the first communication passage, facing upward in the vertical direction, facing the first communication passage, extending in the rotation axis direction so as to be connected to the plurality of ribs, and disposed so as to be located above the photosensitive drum in the vertical direction; having a length of the plurality of receiving portions in the direction of the rotation axis is 50% or more of a length of an image forming area on the photosensitive drum; an image forming apparatus, wherein the plurality of receiving portions are closer to the second opening than to the first opening when viewed in a direction of the rotation axis;

[0129] (Configuration 3) a fixing section configured to heat the recording material, The image forming apparatus according to configuration 1 or 2, characterized in that a second communication passage is formed above the photosensitive drum and below the first communication passage in the vertical direction, and the second communication passage is connected to a transport path through which the recording material transported from the photosensitive drum toward the fixing unit passes, and to the first communication passage.

[0130] (Configuration 4) 4. The image forming apparatus according to claim 3, wherein the receiving surface is located above the second communication passage.

[0131] (Configuration 5) an opposing member having the exposed surface, the plurality of ribs, and the receiving surface, and facing the first communication passage; and an opening / closing member movable between a closed position covering the photosensitive drum and an open position exposing the photosensitive drum, The image forming apparatus according to configuration 3 or 4, characterized in that the opening / closing member is located below the opposing member, and when the opening / closing member is in the closed position, the second communication passage is formed between the opening / closing member and the opposing member.

[0132] (Configuration 6) The image forming apparatus according to configuration 5, further comprising a transfer member facing the photosensitive drum, the opening / closing member supporting the transfer member, the transfer member being in contact with the photosensitive drum when the opening / closing member is in the closed position, and the transfer member being separated from the photosensitive drum when the opening / closing member is in the open position.

[0133] (Configuration 7) The exposed surface has a curved surface that is curved upward in the vertical direction, The image forming apparatus of any one of configurations 1 to 6, characterized in that the curved surface includes a first surface, which, when viewed in the direction of the rotation axis, is located on one side of a vertex of the curved surface in the horizontal direction, extends downward from the vertex, and is located between the vertex and the tip of the receiving surface in the horizontal direction.

[0134] (Configuration 8) 8. The image forming apparatus according to claim 7, wherein the first surface includes a curved surface.

[0135] (Configuration 9) 9. The image forming apparatus according to configuration 7 or 8, wherein the first surface is closer to the second opening than the apex.

[0136] (Configuration 10) The image forming apparatus of any one of configurations 7 to 9, characterized in that the curved surface has a second surface that is located on the other side of the apex of the curved surface in the horizontal direction when viewed in the direction of the rotation axis and is inclined downward from the apex.

[0137] (Configuration 11) 11. The image forming apparatus according to any one of configurations 1 to 10, wherein the first communication passage is a transport path through which the recording material can pass, and the plurality of ribs are configured to guide the recording material.

[0138] (Configuration 12) 12. The image forming apparatus according to any one of configurations 1 to 11, wherein the position of the receiving surface overlaps the position of the photosensitive drum in the direction of the rotation axis.

[0139] (Configuration 13) An image forming apparatus for forming an image on a recording material, an apparatus body including a discharge section provided with a first opening for discharging the recording material, and a wall provided on the opposite side of the discharge section in a horizontal direction and provided with a second opening; a rotatable photosensitive drum that is accommodated in the device body and is disposed below the first opening and the second opening in a vertical direction; an opposing member that is accommodated in the device body, faces a first communication passage that communicates with the first opening and the second opening, and is disposed below the first communication passage; an opening / closing member that is disposed below the opposing member and is movable between a closed position that covers the photosensitive drum and an open position that exposes the photosensitive drum; The opening and closing member is The bottom wall and a first side wall extending along a rotation axis direction of the photosensitive drum and connected to the bottom wall; a second side wall extending along the rotation axis direction, connected to the bottom wall, and facing the first side wall; a third side wall extending along a direction intersecting the rotation axis direction, connected to the bottom wall, the first side wall, and the second side wall; and a fourth side wall extending along a direction intersecting the rotation axis direction, connected to the bottom wall, the first side wall, and the second side wall, and facing the third side wall, when the opening / 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 in the vertical direction from the bottom wall so as to form a recess that is open upward in 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 provided to form the recess, an image forming apparatus characterized in that, when the opening / closing member is in the closed position, the recess is located below a first communication passage that communicates with the first opening and the second opening in the vertical direction and above the photosensitive drum, and the bottom wall faces the opposing member.

[0140] (Configuration 14) a fixing section configured to heat the recording material, The image forming apparatus described in configuration 13, characterized in that a second communication passage is formed above the photosensitive drum and below the first communication passage in the vertical direction, and the second communication passage is connected to a transport path through which the recording material transported from the photosensitive drum toward the fixing unit passes, and to the first communication passage.

[0141] (Configuration 15) 15. The image forming apparatus according to configuration 14, wherein the bottom wall faces the second communication passage when the opening / closing member is in the closed position.

[0142] (Configuration 16) 16. The image forming apparatus according to any one of configurations 13 to 15, wherein when the opening / closing member moves from the closed position to the open position, the recess moves away from the photosensitive drum.

[0143] (Configuration 17) 17. The image forming apparatus of any one of configurations 13 to 16, wherein when the opening / 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 the height of the first side wall.

[0144] (Configuration 18) 18. The image forming apparatus according to any one of configurations 13 to 17, further comprising a transfer member facing the photosensitive drum, the opening / closing member supporting the transfer member, the transfer member being in contact with the photosensitive drum when the opening / closing member is in the closed position, and the transfer member being separated from the photosensitive drum when the opening / closing member is in the open position.

[0145] (Configuration 19) 19. The image forming apparatus of any one of configurations 13 to 18, wherein when the opening / closing member is in the closed position, an upper end of the opening / closing member is located above the photosensitive drum in the vertical direction.

[0146] (Configuration 20) 19. The image forming apparatus according to any one of configurations 1 to 19, wherein the apparatus main body includes a housing having the discharge section, and a door that can be opened and closed relative to the housing and includes the wall. [Explanation of symbols]

[0147] 1 Photosensitive drum 9 Fixing device 11 Double-sided guide 11b1,11b2 receiving rib 13 Transcription Guide 13R Transfer receiver 14a First opening 16 Second opening 100 Image forming device P Recording material CP1 1st communication passage CP2 2nd communication passage

Claims

1. An image forming apparatus for forming an image on a recording material, an apparatus body including a discharge section provided with a first opening for discharging the recording material, and a wall provided with a second opening, the wall being disposed on the opposite side of the discharge section in a horizontal direction; a rotatable photosensitive drum that is accommodated in the device body and is disposed below the first opening and the second opening in a vertical direction; an exposed surface that is housed in the device body and exposed toward a first communication passage that communicates with the first opening and the second opening, the exposed surface being disposed below the first communication passage; a plurality of ribs arranged in a rotational axis direction of the photosensitive drum protruding from the exposed surface toward the first communication passage, the plurality of ribs each extending in a direction intersecting the rotational axis direction; a receiving surface that protrudes from the exposed surface toward the first communication passage, faces upward in the vertical direction, and faces the first communication passage, the receiving surface extending in the rotation axis direction so as to be connected to the plurality of ribs, and is disposed so as to be located above the photosensitive drum in the vertical direction; having An image forming apparatus, characterized in that the receiving surface is inclined with respect to the vertical direction and the horizontal direction so that a tip of the receiving surface is located above a base of the receiving surface that is connected to the exposed surface.

2. An image forming apparatus for forming an image on a recording material, an apparatus body including a discharge section provided with a first opening for discharging the recording material, and a wall provided with a second opening, the wall being disposed on the opposite side of the discharge section in a horizontal direction; a rotatable photosensitive drum that is accommodated in the device body and is disposed below the first opening and the second opening in a vertical direction; an exposed surface that is accommodated in the device body, exposed toward a first communication passage that communicates with the first opening and the second opening, and disposed below the first communication passage; a plurality of ribs arranged in a rotational axis direction of the photosensitive drum protruding from the exposed surface toward the first communication passage, the plurality of ribs each extending in a direction intersecting the rotational axis direction; a plurality of receiving portions, each of which is a receiving surface, the receiving surfaces protruding from the exposed surface toward the first communication passage, facing upward in the vertical direction, facing the first communication passage, extending in the rotation axis direction so as to be connected to the plurality of ribs, and disposed so as to be located above the photosensitive drum in the vertical direction; having a length of the plurality of receiving portions in the direction of the rotation axis is 50% or more of a length of an image forming area on the photosensitive drum, an image forming apparatus, wherein the plurality of receiving portions are closer to the second opening than to the first opening when viewed in a direction of the rotation axis;

3. a fixing section configured to heat the recording material, 2. The image forming apparatus according to claim 1, wherein a second communication passage is formed above the photosensitive drum and below the first communication passage in the vertical direction, and the second communication passage is connected to a transport path through which the recording material transported from the photosensitive drum toward the fixing section passes and to the first communication passage.

4. 4. The image forming apparatus according to claim 3, wherein the receiving surface is located above the second communication passage.

5. an opposing member having the exposed surface, the plurality of ribs, and the receiving surface, and facing the first communication passage; and an opening / closing member movable between a closed position covering the photosensitive drum and an open position exposing the photosensitive drum, 4. The image forming apparatus according to claim 3, wherein the opening / closing member is located below the opposing member, and the second communication passage is formed between the opening / closing member and the opposing member when the opening / closing member is in the closed position.

6. 6. The image forming apparatus according to claim 5, further comprising a transfer member facing the photosensitive drum, the opening / closing member supporting the transfer member, the transfer member contacting the photosensitive drum when the opening / closing member is in the closed position, and the transfer member being separated from the photosensitive drum when the opening / closing member is in the open position.

7. The exposed surface has a curved surface that is curved upward in the vertical direction, 2. The image forming apparatus according to claim 1, wherein the curved surface includes a first surface, the first surface being located on one side of a vertex of the curved surface in the horizontal direction when viewed in the direction of the rotation axis, extending downward from the vertex, and being located between the vertex and the tip of the receiving surface in the horizontal direction.

8. 8. The image forming apparatus according to claim 7, wherein the first surface includes a curved surface.

9. The image forming apparatus according to claim 7 , wherein the first surface is closer to the second opening than the apex.

10. 8. The image forming apparatus according to claim 7, wherein the curved surface has a second surface that is located on the other side of the apex of the curved surface in the horizontal direction when viewed in the direction of the rotation axis and is inclined downward from the apex.

11. 2. The image forming apparatus according to claim 1, wherein the first communication path is a transport path through which the recording material can pass, and the plurality of ribs are configured to guide the recording material.

12. 2. The image forming apparatus according to claim 1, wherein the position of the receiving surface overlaps the position of the photosensitive drum in the direction of the rotation axis.

13. An image forming apparatus for forming an image on a recording material, an apparatus body including a discharge section provided with a first opening for discharging the recording material, and a wall provided on the opposite side of the discharge section in a horizontal direction and provided with a second opening; a rotatable photosensitive drum that is accommodated in the device body and is disposed below the first opening and the second opening in a vertical direction; an opposing member that is accommodated in the device body, faces a first communication passage that communicates with the first opening and the second opening, and is disposed below the first communication passage; an opening / closing member that is disposed below the opposing member and is movable between a closed position that covers the photosensitive drum and an open position that exposes the photosensitive drum; The opening and closing member is The bottom wall and a first side wall extending along a rotation axis direction of the photosensitive drum and connected to the bottom wall; a second side wall extending along the rotation axis direction, connected to the bottom wall, and facing the first side wall; a third side wall extending along a direction intersecting the rotation axis direction, connected to the bottom wall, the first side wall, and the second side wall; and a fourth side wall extending along a direction intersecting the rotation axis direction, connected to the bottom wall, the first side wall, and the second side wall, and facing the third side wall, when the opening / 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 in the vertical direction from the bottom wall so as to form a recess that is open upward in 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 provided to form the recess, an image forming apparatus characterized in that, when the opening / closing member is in the closed position, the recess is located below a first communication passage that communicates with the first opening and the second opening in the vertical direction and above the photosensitive drum, and the bottom wall faces the opposing member.

14. a fixing section configured to heat the recording material, 14. The image forming apparatus according to claim 13, wherein a second communication passage is formed above the photosensitive drum and below the first communication passage in the vertical direction, and the second communication passage is connected to a transport path through which the recording material transported from the photosensitive drum toward the fixing unit passes and to the first communication passage.

15. 15. The image forming apparatus according to claim 14, wherein the bottom wall faces the second communication passage when the opening / closing member is in the closed position.

16. 14. The image forming apparatus according to claim 13, wherein the recessed portion moves away from the photosensitive drum when the opening / closing member moves from the closed position to the open position.

17. 14. The image forming apparatus according to claim 13, wherein when the opening / 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 the height of the first side wall.

18. 14. The image forming apparatus according to claim 13, further comprising a transfer member facing the photosensitive drum, the opening / closing member supporting the transfer member, the transfer member contacting the photosensitive drum when the opening / closing member is in the closed position, and the transfer member being separated from the photosensitive drum when the opening / closing member is in the open position.

19. 14. The image forming apparatus according to claim 13, wherein an upper end of the opening / closing member is located above the photosensitive drum in the vertical direction when the opening / closing member is in the closed position.

20. 20. The image forming apparatus according to claim 1, wherein the apparatus body includes a housing having the discharge portion, and a door that can be opened and closed relative to the housing and includes the wall.

Images