Image forming unit, image forming apparatus, and cooling method for image forming unit

Abstract

The present invention provides an image forming unit, an image forming apparatus, and a cooling method for an image forming unit that can effectively suppress the temperature rise inside the image forming unit. [Solution] The image forming unit (10) attached to the image forming apparatus (1) has a layer restricting member (15) that restricts the thickness of the layer of developer supported on a developer carrier (14) that supplies developer to an image carrier (11), and a cover portion (20) that covers the layer restricting member (15). The cover portion (20) has a first vent (21) provided on one end of the image forming unit (10) in the longitudinal direction (Y) and facing the layer restricting member (15), a second vent (22) provided on the other end of the image forming unit (10) in the longitudinal direction (Y) and facing the layer restricting member (15), and a closed region (23) provided between the first vent (21) and the second vent (22) and facing the layer restricting member (15) at a distance from it.

Description

Technical Field

[0001] The present disclosure relates to an image forming unit, an image forming apparatus, and a method for cooling an image forming unit. Background Art

[0002] Conventionally, as a technique for suppressing temperature rise inside an image forming unit mounted in an image forming apparatus, a cooling technique is known in which air entering from one of openings provided at both ends in the longitudinal direction of the image forming unit is caused to flow through a hollow duct structure penetrating the image forming unit in the longitudinal direction and is discharged from the other opening (see, for example, Patent Document 1). Prior Art Literature Patent Literature

[0003] Patent Document 1 Japanese Unexamined Patent Application Publication No. 2006-208673 (see, for example, Claim 1 and Figure 3) Summary of the Invention Problem to be Solved by the Invention

[0004] However, in the conventional configuration in which cooling is performed by causing air to flow from one of the openings provided at both ends in the longitudinal direction of the image forming unit to the other opening through the hollow duct structure, it has been difficult to obtain a sufficient cooling effect inside the image forming unit.

[0005] The present disclosure has been made in view of the above problem, and an object thereof is to provide an image forming unit, an image forming apparatus, and a cooling method for an image forming unit that can effectively suppress temperature rise inside the image forming unit. Means for Solving the Problem

[0006] The image forming unit of the present disclosure includes a layer restricting member that restricts the thickness of a layer of developer supported on a developer carrier that supplies developer to an image carrier, and a cover portion that covers the layer restricting member. The layer restricting member has one end in the longitudinal direction of the layer restricting member and the other end on the opposite side of the one end in the longitudinal direction, and the cover portion is characterized by having a first vent facing the layer restricting member on the side of the one end from the other end, a second vent facing the layer restricting member on the side of the other end from the one end, and a closed region between the first vent and the second vent that is spaced apart from the layer restricting member and faces the layer restricting member.

[0007] The image forming apparatus of the present disclosure is characterized by comprising the image forming unit described above, a housing that covers the image forming unit, and an intake fan that sends air from outside the housing to the first vent.

[0008] Other image forming units of the present disclosure include a developer carrier that carries a developer supplied to an image carrier, and a cover portion that covers the developer carrier. The developer carrier has one end in the longitudinal direction of the developer carrier and the other end on the opposite side of the one end in the longitudinal direction, and the cover portion is characterized by having a first vent facing the developer carrier on the side of the other end that faces the developer carrier, a second vent facing the developer carrier on the side of the one end that faces the developer carrier, and a closed region between the first vent and the second vent that is spaced apart from the developer carrier and faces the developer carrier.

[0009] Other image forming apparatuses of the present disclosure include the above-described other image forming unit, an optical head portion that exposes the surface of the image carrier to form an electrostatic latent image, a holding portion disposed opposite to the cover portion and holding the optical head portion, a housing that covers the image forming unit, the optical head portion, and the holding portion, and an intake fan that sends outside air into the housing, wherein the holding portion has a first opening into which the air sent into the housing flows, and a second opening that directs the air that has flowed in from the first opening toward the first vent. [Effects of the Invention]

[0010] According to the image forming unit, image forming apparatus, and cooling method for the image forming unit of this disclosure, the rise in internal temperature of the image forming unit can be effectively suppressed. [Brief explanation of the drawing]

[0011] [Figure 1] This is a longitudinal cross-sectional view schematically showing the configuration of the image forming apparatus according to Embodiment 1. [Figure 2] This is a longitudinal cross-sectional view schematically showing the configuration of the image forming unit according to Embodiment 1. [Figure 3] This is a schematic plan view showing the configuration of the image forming apparatus according to Embodiment 1. [Figure 4] This is a schematic front view showing the configuration of the exposure unit of the image forming apparatus according to Embodiment 1. [Figure 5] This is a schematic plan view showing a part of the configuration of the head holder of the exposure unit of the image forming apparatus according to Embodiment 1. [Figure 6] This is an external perspective view that schematically shows the configuration of the cover portion of the image forming unit according to Embodiment 1. [Figure 7] This is a magnified view of the main part of Figure 6. [Figure 8] This is a schematic plan view showing the configuration of the image forming unit and exposure unit according to Embodiment 1. [Figure 9]It is a plan view schematically showing the configuration of an image forming apparatus according to Embodiment 2. [Figure 10] It is an external perspective view schematically showing the configuration of a cover portion of an image forming unit of the image forming apparatus according to Embodiment 2. [Figure 11] It is a front view schematically showing the configuration of an exposure unit of the image forming apparatus according to Embodiment 2. DESCRIPTION OF EMBODIMENTS

[0012] Hereinafter, an image forming unit, an image forming apparatus with the image forming unit mounted thereon, and a cooling method for the image forming unit according to embodiments will be described with reference to the drawings. The following embodiments are merely examples, and the embodiments can be modified as appropriate.

[0013] Coordinate axes of an XYZ orthogonal coordinate system are shown in the drawings. The X-axis is a coordinate axis along the widthwise direction of the image forming unit (that is, the X direction extending from the rear portion toward the front surface of the image forming apparatus). The Y-axis is a coordinate axis along the longitudinal direction of the image forming unit (that is, the Y direction corresponding to the width direction of the image forming apparatus). The Z-axis is a coordinate axis along the height direction of the image forming unit (that is, the Z direction corresponding to the height direction of the image forming apparatus).

[0014] Embodiment 1 Image Forming Apparatus 1 and Image Forming Unit 10 FIG. 1 is a longitudinal sectional view schematically showing the configuration of an image forming apparatus 1 according to Embodiment 1. FIG. 2 is a longitudinal sectional view schematically showing the configuration of an image forming unit 10 according to Embodiment 1. The image forming apparatus 1 is a monochrome printer that forms monochrome images by an electrophotographic process. The image forming apparatus 1 may be a color printer that forms color images by an electrophotographic process. Further, the image forming apparatus 1 may be a facsimile machine, a copier, a multifunction peripheral, or the like. In FIG. 1, a part of the internal structure of the image forming unit 10 is shown.

[0015] The image forming unit 10 is detachably mounted on the image forming apparatus 1. The image forming unit 10 is also called an image drum (ID) unit. The image forming unit 10 mounted on the image forming apparatus 1 is a part of the image forming apparatus 1. The image forming apparatus 1 is an apparatus capable of implementing the cooling method for the image forming unit 10 according to Embodiment 1.

[0016] The image forming apparatus 1 includes a housing 1a serving as an enclosure, and an upper cover 1b serving as a cover member that is openably and closably supported on the housing 1a. The upper cover 1b rotates around a support shaft 1d by an opening / closing operation performed by a user, to open and close the upper opening of the housing 1a.

[0017] Inside the housing 1a, the image forming apparatus 1 includes a media cassette 30 that accommodates a medium M as a print medium, a media supply unit 40 that feeds the medium M accommodated in the media cassette 30, the image forming unit 10 that forms an image, a transfer unit 50 that transfers an image onto the medium M, a fixing unit 70 as a fixing device that fixes an image onto the medium M, a medium discharge unit 80 that conveys the medium M and discharges it from a medium discharge port 1c onto a stacker 1e, and a return conveying unit 90 used for duplex printing that prints images on both sides (i.e., the front side and the back side) of the medium M. The medium M is, for example, paper or a film.

[0018] Inside the housing 1a, the image forming apparatus 1 has medium conveyance paths R1, R2, R3, and R4 which are paths through which the medium M is conveyed. The medium conveyance paths R1, R2, and R3 are paths for conveying the medium M from the media cassette 30 through the media supply unit 40, the transfer unit 50, and the fixing unit 70 to the medium discharge port 1c. The medium conveyance path R4 is a return conveyance path for reversing the front and back sides of the medium M and returning it to the medium conveyance path R1 during duplex printing.

[0019] The media cassette 30 is detachably mounted at the bottom of the housing 1a. When removing the media cassette 30, the media cassette 30 is pulled out of the housing 1a in the X direction by the user. When installing the media cassette 30, the media cassette 30 is inserted into the housing 1a in the -X direction by the user.

[0020] The media supply unit 40 includes a pickup roller 41, a paper feed roller 42, a separation roller 43, a registration roller 44, a pressure roller 45, and a transport roller pair 46. The pickup roller 41 pulls out the media M loaded in the media cassette 30 from the media cassette 30. The paper feed roller 42 and the separation roller 43 separate the pulled-out media M one sheet at a time and send them to the media transport path R1. The registration roller 44 and the pressure roller 45 transport the media M toward the transport roller pair 46. The transport roller pair 46 corrects the skew of the media M and transports the media M to the media transport path R2, which includes the position where the transfer unit 50 is located.

[0021] The image forming unit 10 includes a photoreceptor drum 11 as an image carrier, a charging roller 12 as a charging member, a toner supply roller 13 as a developer supply member, a developer roller 14 as a developer carrier, a layer restricting member 15, a cleaning blade 16 as a cleaning member to remove residual developer (residual toner) and the like adhering to the surface of the photoreceptor drum 11, a cover portion 20 which is a housing structure that houses these components, and a toner cartridge 17 which is a developer container that houses replenishment developer (toner). The photoreceptor drum 11 rotates clockwise in Figures 1 and 2.

[0022] The image forming apparatus 1 has an exposure unit 60 positioned inside the housing 1a, facing the photoreceptor drum 11. The exposure unit 60 has a head holder 61 as a holding part and an LED (Light Emitting Diode) head 62. The LED head 62 has an LED array (not shown) in which LEDs as light-emitting elements are arranged and a lens array (not shown) in which lenses are arranged, and exposes the surface of the photoreceptor drum 11 based on image data transmitted from a higher-level device to the image forming apparatus 1 to form an electrostatic latent image based on the image data. The LED head 62 is held in the head holder 61 fixed inside the upper cover 1b. The exposure unit 60 can use a laser optical system using a semiconductor laser instead of the LED head 62.

[0023] When the upper cover 1b is opened, the LED head 62 and the head holder 61 that supports it are lifted together with the upper cover 1b and separated from the cover portion 20 of the image forming unit 10. At this time, the image forming unit 10 becomes detachable from the housing 1a. When the upper cover 1b is closed, as shown in Figure 1, the LED head 62 and the head holder 61 that supports it are positioned close to the cover portion 20 of the image forming unit 10 together with the upper cover 1b.

[0024] The charging roller 12 is positioned to contact the surface of the photoreceptor drum 11 and rotates in accordance with the rotation of the photoreceptor drum 11. A charging voltage is applied to the charging roller 12, uniformly charging the surface of the photoreceptor drum 11.

[0025] The toner supply roller 13 is positioned to contact the surface of the developing roller 14 and rotates in the same direction as the developing roller 14 (in a direction opposite to the direction of surface movement at the contact point). The toner supply roller 13 is supplied with toner to the developing roller 14 when a supply voltage is applied.

[0026] The developing roller 14 is positioned to contact the surface of the photoreceptor drum 11 and rotates in the opposite direction to the photoreceptor drum 11 (in the direction in which the surface moves at the contact point is the forward direction). When a developing voltage is applied to the developing roller 14, a developer layer (toner layer) is formed on its surface. The toner layer of the developing roller 14 moves to the electrostatic latent image on the surface of the photoreceptor drum 11 using Coulomb force, and the electrostatic latent image becomes a developer image (toner image).

[0027] The layer regulating member 15 includes a developing blade 15a and a support member 15b attached to the cover portion 20 and supporting the developing blade 15a. The developing blade 15a has a fixed end 15aa fixed to the cover portion 20 by the support member 15b and a tip-side contact portion 15ab that contacts the surface of the developing roller 14, and this tip-side contact portion 15ab regulates the thickness of the toner layer carried on the surface of the developing roller 14. Generally, the developing blade 15a is formed using a plate-shaped member made of metal (e.g., SUS301) in order to make the pressure applied to the developing roller 14 by the tip-side contact portion 15ab constant (i.e., uniform) throughout the entire Y direction. In addition, the support member 15b of the layer regulating member 15 is constructed using rigid members 15ba and 15bb (e.g., metal such as galvanized steel) throughout the entire Y direction.

[0028] The toner cartridge 17 has a container for storing replenishment toner and is detachably attached to the image forming unit 10. The toner cartridge 17 supplies toner into the developer storage section which houses the developing roller 14 and the toner supply roller 13. The developer storage section is part of the housing structure of the image forming unit 10.

[0029] The transfer unit 50 is located on the opposite side of the image forming unit 10, across the medium transport path R2. The transfer unit 50 is located on the -Z side (lower side in Figure 1) of the image forming unit 10 and has a transfer roller 51 that contacts the surface of the photoreceptor drum 11. A transfer voltage is applied to the transfer roller 51. The toner image on the surface of the photoreceptor drum 11 is transferred to the medium M that passes between the photoreceptor drum 11 and the transfer roller 51. The medium M that has passed between the photoreceptor drum 11 and the transfer roller 51 is transported along the medium transport path R2 toward the fuser unit 70 by the rotation of the photoreceptor drum 11.

[0030] The fixing unit 70 is positioned downstream of the image forming unit 10 in the transport direction of the medium M. The fixing unit 70 has a fixing roller 71 as a fixing member and a pressure roller 72 as a pressurizing member. The fixing roller 71 has a built-in heater such as a halogen lamp. The pressure roller 72 is pressed against the fixing roller 71. The fixing roller 71 and the pressure roller 72 heat and pressurize the medium M passing between them, fixing the toner image to the medium M. The image forming apparatus 1 may also have a duct 73 for passing air and an open space 74 inside. The duct 73 and the open space 74 make it difficult for the heat generated in the fixing unit 70 to be transferred to the image forming unit 10.

[0031] The media discharge section 80 has a discharge roller pair 81 and a discharge roller pair 82 along the media transport path R3 from the fixing unit 70 to the media discharge port 1c of the upper cover 1b. The discharge roller pair 81 and the discharge roller pair 82 transport the media M that has passed through the fixing unit 70 along the media transport path R3 and discharge it from the media discharge port 1c onto the stacker 1e, which is the upper surface of the upper cover 1b.

[0032] Furthermore, the image forming apparatus 1 may have a return transport unit 90 for returning the medium M on which the toner image has been fixed to the medium transport path R1 for double-sided printing. The return transport unit 90 includes a switching guide 91 as a transport path switching unit, a medium transport path R4 which is the path from the downstream side of the fixing unit 70 to the medium transport path R1, and transport roller pairs 92, 93, and 94 for transporting the medium M along the medium transport path R4.

[0033] The switching guide 91 is located downstream of the fixing unit 70 and switches the transport path of the media M based on a command from the control unit (not shown) of the image forming apparatus 1. When the image forming apparatus 1 is instructed to print on one side, the media M that has passed through the fixing unit 70 passes through the switching guide 91, the discharge roller pair 81, and the discharge roller pair 82, and is discharged onto the stacker 1e from the media discharge port 1c. When the image forming apparatus 1 is instructed to print on both sides, the media M that has passed through the fixing unit 70 stops after passing through the switching guide 91, is sent to the media transport path R4 by the discharge roller pairs 81 and 82, and is transported to the media transport path R1 upstream of the transport roller pair 46 by the transport roller pairs 92, 93, and 94. The image forming apparatus 1 may be configured without a return transport section 90.

[0034] In Figures 1 and 2, the longitudinal direction of the image forming unit 10 (i.e., the longitudinal direction of the developing roller 14 and the axial direction of the developing roller 14) is the Y direction. The direction of movement of the medium M when it passes through the image forming unit 10 in the medium transport path R2 (i.e., the direction intersecting the axial direction of the developing roller 14 and the short direction of the developing roller 14) is the X direction.

[0035] <Airflow 16a~16g> Figure 3 is a schematic plan view showing the configuration of the image forming apparatus 1 according to Embodiment 1. As shown in Figure 2 or Figure 3, the image forming unit 10 has a layer regulating member 15 that regulates the thickness of the toner layer supported on the developing roller 14 that supplies toner to the photoreceptor drum 11, and a cover portion 20 that covers the layer regulating member 15 and the like. The cover portion 20 has a first vent 21 provided on one end in the Y direction (longitudinal direction of the image forming unit 10) and facing the layer regulating member 15, a second vent 22 provided on the other end in the Y direction (longitudinal direction of the image forming unit 10) and facing the layer regulating member 15, and a closed region 23 provided between the first vent 21 and the second vent 22 and spaced apart from and facing the layer regulating member 15. In other words, the layer restricting member 15 has one end in the longitudinal direction of the layer restricting member 15 and the other end on the opposite side of the longitudinal direction of this end, and the cover portion 20 has a first vent 21 facing the layer restricting member 15 on the side of the other end facing the layer restricting member 15, a second vent 22 facing the layer restricting member 15 on the side of the one end facing the other end, and a closed region 23 between the first vent 21 and the second vent 22 that is spaced away from the layer restricting member 15 and facing the layer restricting member 15. The closed region 23 is a region that does not have an opening. The layer restricting member 15 has a developing blade 15a facing the surface of the developing roller 14, and a support member 15b attached to the cover portion 20 and supporting the developing blade 15a. The first vent 21 and the second vent 22 are arranged to face the layer restricting member 15 with a space 24 in between. For example, the cover portion 20 has a wall portion 27 that extends in the Y direction opposite to at least a part of the layer restricting member 15, and the wall portion 27 has a first vent 21, a second vent 22, and a closed area 23. In addition, a space 24 is formed between the wall portion 27 and the layer restricting member 15, and the first vent 21 and the second vent 22 are in communication with the space 24.

[0036] Furthermore, the positional relationship between the first vent 21, the second vent 22, the occluded area 23, and the image forming unit 10 can also be described as follows. The cover portion 20 of the image forming unit 10 has a first vent 21 provided on one end in the Y direction (longitudinal direction of the image forming unit 10) and facing the surface of the developing roller 14, a second vent 22 provided on the other end in the Y direction (longitudinal direction of the image forming unit 10) and facing the surface of the developing roller 14, and an occluded area 23 provided between the first vent 21 and the second vent 22 and facing the surface of the developing roller 14 at a distance from it. The first vent 21 and the second vent 22 are arranged to face the surface of the developing roller 14 with a space 24 in between.

[0037] The first vent 21, the closed area 23, and the second vent 22 are arranged in the Y direction on the same surface (i.e., the wall surface 27) that constitutes part of the cover portion 20. As shown by the airflow 26a to 26g indicated by the thick arrows in Figure 2, paths are formed for air to flow through the first vent 21, the space 24 inside the closed area 23, and the second vent 22. The positions of the first vent 21, the closed area 23, and the second vent 22 are not limited to the illustrated example, but are acceptable as long as they are positions where paths for air to flow through the first vent 21, the space 24 inside the closed area 23, and the second vent 22 are formed. For example, one of the first vent 21 and the second vent 22 may be arranged side by side on a first surface (e.g., wall surface 27) which is the same surface as the closed area 23, while the other of the first vent 21 and the second vent 22 may be arranged on a surface different from the first surface (e.g., a surface perpendicular to the wall surface 27). Also, although the wall surface 27 is a plane parallel to the Y direction, the wall surface 27 does not have to be parallel to the Y direction. For example, the wall surface 27 may include a surface that is inclined with respect to the Y direction. Alternatively, the inner surface of the closed area 23 may be a surface that is inclined with respect to the Y direction or a curved surface.

[0038] As shown in Figure 3, the housing 1a covering the image forming unit 10 is provided with an intake port 111 for supplying air from outside the housing 1a to a first vent 21, and an intake fan 110 is provided at the intake port 111. The housing 1a is also provided with an exhaust port 121 for discharging air discharged from inside the cover portion 20 through a second vent 22 to the outside of the housing 1a, and an exhaust fan 120 is provided at the exhaust port 121. The positions of the intake fan 110 and the exhaust fan 120 are not limited to the illustrated example and may be in other positions. Furthermore, it is possible to provide an intake fan 110 but not an exhaust fan 120, or to provide an exhaust fan 120 but not an intake fan 110. Furthermore, in Figure 3, a structure may be adopted in which the first vent 21, intake port 111, and intake fan 110 are swapped with the second vent 22, exhaust port 121, and exhaust fan 120 (a structure in which the left and right sides are reversed when viewed in the X direction in Figure 3).

[0039] <Head holder 61> Figure 4 is a schematic front view showing the configuration of the exposure unit 60 of the image forming apparatus 1 according to Embodiment 1. Figure 5 is a schematic plan view showing a part of the configuration of the head holder 61 of the exposure unit 60 of the image forming apparatus 1 according to Embodiment 1.

[0040] As shown in Figures 4 and 5, the head holder 61 has a first opening 63 through which air supplied from outside the housing 1a into the housing 1a by the airflow 26a flows in (i.e., in the direction of flow 26b), and a second opening 64 that directs the air that has flowed into the space inside the head holder 61 from the first opening 63 toward the first vent 21 of the cover portion 20 (in the direction of flow 26c). The air that has flowed into the cover portion 20 from the second opening 64 flows inside the closed region 23 (in the direction of flow 26d) toward the second vent 22.

[0041] The head holder 61 has a third opening 65 positioned opposite the second vent 22, and a fourth opening 66 positioned opposite the third opening 65. Air flowing into the head holder 61 from the third opening 65 passes through the fourth opening 66 (in the direction of flow 26e) and is discharged into a passage communicating with the exhaust fan 120. The air is then flowed by the exhaust fan 120 in the direction of flow 26g and discharged to the outside of the housing 1a. The head holder 61 also has a flat cable 67 extending upward from the LED head 62. The flat cable 67 is located in the center of the LED head 62 in the Y direction (between the second opening 64 and the third opening 65). This is to ensure that the opening areas of the first opening 63 provided at one end of the head holder 61 in the Y direction, the second opening 64 provided near the other end of the head holder 61 in the Y direction, and the third opening 65 and fourth opening 66 provided near the other end of the head holder 61 in the Y direction are sufficiently large, so as not to obstruct the airflow through each opening.

[0042] Air sent from outside the housing 1a into the housing 1a and into the head holder 61 is bent by the walls of the head holder 61 and directed towards the image forming unit 10. The angle at which the air is bent by the walls of the head holder 61 is preferably 20° to 30°. If the angle is too small, the air will not reach the first vent 21 of the image forming unit 10. If the angle is too large, it will obstruct the airflow that is trying to send to the first vent 21. If the angle at which the airflow is bent by the walls of the head holder 61 is in the range of 20° to 30°, the airflow will not be obstructed, and air can be sent to the first vent 21 of the image forming unit 10 over a wide range. In Embodiment 1, the angle at which the airflow is bent by the walls of the head holder 61 was set to 26°.

[0043] Regarding the respective opening widths of the intake port 111 and exhaust port 121, the opening area of ​​the exhaust port 121 is made larger than the opening area of ​​the intake port 111. This is to efficiently expel the air that enters through the intake port 111 through the exhaust port 121.

[0044] <First ventilation opening 21, second ventilation opening 22, closed area 23> Figure 6 is a schematic external perspective view showing the configuration of the cover portion 20 of the image forming unit 10 according to Embodiment 1. Figure 7 is an enlarged view showing the main part of Figure 6. Figure 8 is a schematic plan view showing the configuration of the image forming unit 10 and exposure unit 60 according to Embodiment 1.

[0045] The first ventilation opening 21 of the cover portion 20 has a plurality of first ribs 21b arranged in the Y direction (longitudinal direction of the image forming unit 10). A first slit is formed on both sides of each of the plurality of first ribs 21b in the Y direction (longitudinal direction of the image forming unit 10). Each of the plurality of first ribs 21b has a first end 21ba on the inside of the cover portion 20 and a second end 21bb on the outside of the cover portion 20, and each of the plurality of first ribs 21b is inclined such that the first end 21ba is closer to the closed region 23 than the second end 21bb. A preferred inclination angle of the first ribs 21b with respect to the YZ plane is, for example, 45°, but the inclination angle is not limited to 45°.

[0046] The second ventilation opening 22 of the cover portion 20 has a plurality of second ribs 22b arranged in the Y direction. A second slit 22a is formed on both sides of each of the plurality of second ribs 22b in the Y direction. Each of the plurality of second ribs 22b has a third end 22ba on the inside of the cover portion 20 and a fourth end 22bb on the outside of the cover portion 20. Each of the plurality of second ribs 22b is inclined such that the third end 22ba is closer to the closed region 23 than the fourth end 22bb. A preferred inclination angle of the second ribs 22b with respect to the YZ plane is, for example, 45°, but the inclination angle is not limited to 45°.

[0047] <Operation> First, the media M stored in the media cassette 30 is picked up by the pickup roller 41, and then the media M is transported one by one to the media transport paths R1 and R2. In the image forming unit 10, an electrostatic latent image is formed on the surface of the photoreceptor drum 11, and the toner image formed by toner adhering to the electrostatic latent image is transferred to the media M by the transfer roller 51. Next, the toner image transferred to the media M is heated and pressurized by the fixing unit 70, and the toner is fixed to the media M. After that, the media M on which the image has been formed is discharged onto the stacker 1e.

[0048] In the case of double-sided printing, after the media M is transported to the media transport path R3, the media M is transported in the reverse direction, passes through the media transport path R4, and is transported to the media transport path R1 with the front and back sides reversed. After printing on the back side of the media M is completed, the media M is discharged onto the stacker 1e.

[0049] When such image forming processes are carried out continuously, the sliding friction between the toner supply roller 13 and the developing roller 14, the sliding friction between the photoreceptor drum 11 and the developing roller 14, and the sliding friction between the developing roller 14 and the layer restricting member 15 generates heat, causing the temperature inside the image forming unit 10 to rise.

[0050] Furthermore, when printing on both sides of the medium M, the medium M is heated as it passes through the fuser unit 70 during printing on the front side. This heated medium M then passes through the photoreceptor drum 11 during printing on the back side. At this time, the heat from the medium M is transferred to the photoreceptor drum 11, and the image forming unit 10 is heated. Due to these two factors, the inside of the image forming unit 10 becomes hot when continuous printing is performed.

[0051] When heat builds up inside the image forming unit 10, the toner deteriorates, making it more susceptible to detachment of external additives and toner aggregation. This can lead to toner charging problems, deterioration of toner fluidity, changes in print density, streaking, fogging, and other image defects.

[0052] On the other hand, in recent years, low-melting-point toners have been used to save energy in image forming apparatuses. However, these low-melting-point toners are prone to image defects even at low temperatures.

[0053] The image forming apparatus 1 has a control unit (for example, an information processing circuit not shown) that controls the operation of the apparatus, and can implement the cooling method for the image forming unit 10 according to Embodiment 1. The cooling method for the image forming unit 10 according to Embodiment 1 includes the steps of driving an intake fan 110 that sends outside air from the housing 1a covering the image forming unit 10 to a first vent 21 of the cover portion 20, and driving an exhaust fan 120 that discharges air discharged from inside the cover portion 20 through a second vent 22 to the outside of the housing 1a.

[0054] This cooling operation can be controlled, for example, during printing, or by providing a temperature sensor, so that the cooling operation is executed when the temperature sensor's detected value exceeds a set value. Furthermore, the positions of the intake fan 110 and exhaust fan 120 are not limited to those shown in the figure. Also, the number of intake fans 110 is not limited to one, but may be two or more. Similarly, the number of exhaust fans 120 is not limited to one, but may be two or more.

[0055] <effect> The temperature rise inside the image forming unit 10 is largely due to the heat generated by the sliding friction between the layer restricting member 15 and the developing roller 14. The first vent 21 and the second vent 22 are provided facing the layer restricting member 15. Therefore, the heat generated by the sliding friction between the layer restricting member 15 and the developing roller 14 is efficiently discharged to the outside of the housing 1a by the first vent 21 and the second vent 22. According to Embodiment 1, the heat generated by the sliding friction between the tip-side contact portion 15ab of the developing blade 15a and the developing roller 14 is also largely related. The heat generated at the tip-side contact portion 15ab is transferred (heat transferred) to the support member 15b via the developing blade 15a. In contrast, the first vent 21 and the second vent 22 are provided facing the support member 15b of the developing blade 15a. Therefore, the heat transferred from the developing blade 15a to the support member 15b is efficiently discharged to the outside of the housing 1a through the first vent 21 and the second vent 22. This allows for efficient cooling of the layer restricting member 15 and the inside of the image forming unit 10.

[0056] Furthermore, since the end regions of the layer restricting member 15 and the developing roller 14 correspond to the non-feeding regions in the width direction of the medium M, no temperature drop occurs as the medium M passes through. In Embodiment 1, the first vent 21 and the second vent 22, which are formed on the longitudinal side of the closed region 23, can effectively dissipate heat from the end regions to the outside of the image forming unit 10.

[0057] Furthermore, according to Embodiment 1, it is possible to continuously remove heat from inside the image forming unit 10 even during printing. As a result, the temperature rise inside the image forming unit 10 can be suppressed, and even when using low-melting-point toner, a decrease in throughput and a decrease in print quality are less likely to occur, enabling continuous printing. In Embodiment 1, the temperature rise caused by continuous printing is suppressed for the image forming unit 10 and the exposure unit 60, allowing printing to continue without a decrease in printing speed or waiting time.

[0058] Furthermore, by driving the intake fan 110 and exhaust fan 120 during the printing operation of the image forming apparatus 1, an airflow 26d (Figure 3) is generated inside the image forming unit 10, thereby suppressing temperature rise caused by self-heating due to sliding friction and heat received from the double-sided printing medium.

[0059] The first vent 21 and the second vent 22 are provided facing the layer restricting member 15. Therefore, the layer restricting member 15 is cooled by the air flowing from the first vent 21 to the second vent 22, and the heat of the layer restricting member 15 is efficiently discharged to the outside of the housing 1a by the air flowing from the second vent 22 through the third opening 65 and the fourth opening 66. According to Embodiment 1, the first vent 21 and the second vent 22 are provided facing the support member 15b of the developing blade 15a. Therefore, the support member 15b, to which the heat generated by the developing blade 15a is transferred, is cooled by the air flowing from the first vent 21 to the second vent 22, and the heat of the support member 15b is efficiently discharged to the outside of the housing 1a by the air flowing from the second vent 22 through the third opening 65 and the fourth opening 66. This allows for efficient cooling of the layer restricting member 15 and the image forming unit 10.

[0060] Furthermore, by providing a closed region 23 between the first vent 21 and the second vent 22, air can flow along the longitudinal direction (Y direction) of the layer restricting member 15 from one end (the first vent 21 side) to the other end (the second vent 22 side). This allows the layer restricting member 15 to be effectively cooled. Moreover, because air can flow from one end (the first vent 21 side) to the other end (the second vent 22 side) of the layer restricting member 15 (i.e., the air does not escape along the way), air can be guided through the third opening 65 and the fourth opening 66 of the head holder 61 to the exhaust fan 120. This prevents the air heated by the layer restricting member 15 from accumulating in the image forming unit 10, improving the cooling efficiency of the layer restricting member 15 and the image forming unit 10.

[0061] Furthermore, the air flowing into the image forming unit 10 from the first vent 21 is bent by the first rib 21b and directed toward the center of the layer restricting member 15. As a result, air can flow along the longitudinal direction (Y direction) of the layer restricting member 15 from one end (the first vent 21 side) to the other end (the second vent 22 side), and the air can be guided through the third opening 65 and the fourth opening 66 of the head holder 61 to the exhaust fan 120. This prevents the air heated by the layer restricting member 15 from accumulating inside the image forming unit 10, improving the cooling efficiency of the layer restricting member 15 and the image forming unit 10.

[0062] Furthermore, air from the intake fan 110 is bent at less than 90° via the head holder 61 and sent through the first vent 21. This allows air to be sent into the image forming unit 10 from the first vent 21 without obstructing the airflow. This enhances the effect of suppressing the retention of air heated by the layer restricting member 15 within the image forming unit 10, thereby improving the cooling efficiency of the layer restricting member 15 and the image forming unit 10.

[0063] Furthermore, the air discharged from the second vent 22 to the outside of the image forming unit 10 is bent by the second rib 22b and directed toward the third opening 65 and the fourth opening 66. This allows the air to be efficiently guided from the second vent 22 through the third opening 65 and the fourth opening 66 to the exhaust fan 120. As a result, the layer regulating member 15 and the inside of the image forming unit 10 can be efficiently cooled.

[0064] Furthermore, a sealing material is attached to the end face of the developing roller 14 to prevent toner from leaking out of the image forming unit 10. Toner accumulates on the end face of this sealing material, so if there is an airflow towards the end face of the developing roller 14, the toner will be stirred up, and this stirred-up toner will adhere to the LED head 62 and the photoreceptor drum 11, resulting in a defective print image. By bending the air flowing into the image forming unit 10 from the first vent 21 towards the center of the developing roller 14 using the first rib 21b, the stirring up of toner (toner scattering) can be reduced.

[0065] Furthermore, according to Embodiment 1, since it is possible to continuously absorb heat from inside the image forming unit 10 even during printing, the inside of the image forming unit 10 does not become too hot, and even when using low-melting-point toner, continuous printing is possible without a decrease in throughput or print quality.

[0066] Embodiment 2 Figure 9 is a schematic plan view showing the configuration of the image forming apparatus 2 according to Embodiment 2. In Figure 9, components that are the same as or corresponding to those shown in Figure 3 are denoted by the same reference numerals as those shown in Figure 3. The image forming apparatus 2 differs from the image forming apparatus 1 according to Embodiment 1 in terms of the structure of the cover portion 20a of the image forming unit 10a and the structure of the exposure unit 60a. In other respects, Embodiment 2 is the same as Embodiment 1. For this reason, the description of Embodiment 2 will also refer to Figures 1 and 2 showing Embodiment 1. Below, the image forming apparatus 2 according to Embodiment 2 will be described, focusing on the differences from the image forming apparatus 1 according to Embodiment 1.

[0067] The image forming unit 10a includes a photosensitive drum 11 as an image carrier, a developing roller 14 that supplies developer to it, a layer regulating member 15 that regulates the thickness of the developer layer on the developing roller 14, and a cover portion 20a that covers the layer regulating member 15.

[0068] Figure 10 is a schematic external perspective view showing the configuration of the cover portion 20a of the image forming unit 10a of the image forming apparatus 2 according to Embodiment 2. In Figure 10, components that are the same as or corresponding to the components shown in Figure 6 are denoted by the same reference numerals as those shown in Figure 6. The layer restricting member 15 has one end in the longitudinal direction (Y direction) of the layer restricting member 15, and the other end on the opposite side of this end in the longitudinal direction. The cover portion 20a has a ventilation opening 28 that extends in the Y direction from the one end to the other end. For example, the cover portion 20a of Embodiment 2 has one ventilation opening 28, and this ventilation opening 28 is an opening with an area approximately equal to the area occupied by the first ventilation opening 21, the closed region 23, and the second ventilation opening 22 in Embodiment 1.

[0069] Figure 11 is a schematic front view showing the configuration of the exposure unit 60a of the image forming apparatus 2 according to Embodiment 2. In Figure 11, components that are the same as or corresponding to those shown in Figure 4 are denoted by the same reference numerals as those shown in Figure 4. The exposure unit 60a has a wall portion 68. The wall portion 68 is located between the second opening 64 and the third opening 65, in the region facing the ventilation opening 28. The wall portion 68 has a function similar to that of the closed region 23 in Embodiment 1.

[0070] The position and shape of the vent 28 are not limited to the illustrated example, and may be any position and shape that forms a path for air to flow through the second opening 64, the space 24a, and the third opening 65. For example, the wall surface 27 does not have to be parallel to the Y direction. For example, the wall surface 27 may include a surface that is inclined with respect to the Y direction.

[0071] As shown in Figure 9, the head holder 61 has a first opening 63 through which air supplied from outside the housing 1a into the housing 1a by the airflow 26a flows in (i.e., in the direction of flow 26b), and a second opening 64 that directs the air flowing from the first opening 63 into the space inside the head holder 61 toward the vent 28 of the cover portion 20 (in the direction of flow 26c). The air flowing from the second opening 64 into the cover portion 20 flows through the space 24a between the layer restricting member 15 and the wall portion 68 (in the direction of flow 26d) toward the third opening 65. The wall portion 68 allows air to flow in the longitudinal direction (Y direction) of the layer restricting member 15 from one end (the second opening 64 side) to the other end (the third opening 65 side). This allows the layer restricting member 15 to be effectively cooled.

[0072] The head holder 61 has a third opening 65 positioned opposite the vent 28 and a fourth opening 66 positioned opposite the third opening 65. Air flowing into the head holder 61 from the vent 28 through the third opening 65 passes through the fourth opening 66 (in the direction of flow 26e) and is discharged into a passage communicating with the exhaust fan 120. The air is then flowed by the exhaust fan 120 in the direction of flow 26g and discharged to the outside of the housing 1a.

[0073] In the image forming unit 10a according to Embodiment 2, the vent 28 is provided facing the support member 15b of the developing blade 15a. As a result, the heat generated by the developing blade 15a is transferred to the support member 15b, which flows from the second opening 64 towards the vent 28, and is cooled by the air passing through the space 24a between the support member 15b and the wall portion 68. The heat from the support member 15b is efficiently discharged to the outside of the housing 1a by the air flowing through the vent 28, the third opening 65, and the fourth opening 66. This allows for efficient cooling of the layer restricting member 15 and the inside of the image forming unit 10a.

[0074] [Note] The various aspects of this disclosure are summarized below as an appendix. (Note 1) A layer restricting member that restricts the thickness of the developer layer supported on a developer carrier that supplies the developer to an image carrier, A cover portion that covers the layer restricting member, In an image forming unit having, The layer restricting member has one end in the longitudinal direction of the layer restricting member, and the other end on the opposite side of the one end in the longitudinal direction. The aforementioned cover portion is On the side of the other end toward the one end, a first ventilation opening facing the layer restricting member is provided, A second ventilation opening facing the layer restricting member is located on the other end side from the one end, Between the first vent and the second vent, there is a closed region spaced apart from the layer restricting member and facing the layer restricting member, has An image forming unit characterized by the following features. (Note 2) The cover portion has a wall portion that extends in the longitudinal direction and faces at least a part of the layer restricting member, The wall portion has the first ventilation opening, the second ventilation opening, and the closed region. The image forming unit according to Appendix 1, characterized in that it is a product of the present invention. (Note 3) A space is formed between the wall surface and the layer restricting member. The first vent and the second vent communicate with the space. The image forming unit described in Appendix 2, characterized by the features described herein. (Note 4) The aforementioned layer restricting member is A developing blade facing the surface of the developer carrier, A support member attached to the cover portion to support the developing blade, It has, The first vent and the second vent are separated from the support member and face each other across the space. The image forming unit according to Appendix 3, characterized by the features described herein. (Note 5) The developing blade and the support member are made of metal. The image forming unit described in Appendix 4, characterized by the features described herein. (Note 6) A developer carrier that carries the developer supplied to the image carrier, A cover portion that covers the developer carrier, In an image forming unit having, The developer carrier has one end in the longitudinal direction of the developer carrier, and the other end on the opposite side of the one end in the longitudinal direction. The aforementioned cover portion is A first vent facing the developer carrier is located on the side of the other end that is closer to the one end, A second vent facing the developer carrier is located on the other end side from the one end, Between the first vent and the second vent, there is a closed region that is spaced apart from the developer carrier and facing the developer carrier, has An image forming unit characterized by the following features. (Note 7) The first vent and the second vent are separated by a space and face the developer carrier. The image forming unit according to Appendix 6, characterized in that it is a product of the present invention. (Note 8) The first vent has a plurality of first ribs arranged in the longitudinal direction, The second ventilation opening has a plurality of second ribs arranged in the longitudinal direction, A first slit is formed on both sides of the longitudinal direction of each of the plurality of first ribs. A second slit is formed on both sides of each of the plurality of second ribs in the longitudinal direction. An image forming unit according to any one of the appendices 1 to 7, characterized in that it is an image forming unit. (Note 9) Each of the plurality of first ribs has a first end on the inside of the cover portion and a second end on the outside of the cover portion. Each of the plurality of second ribs has a third end on the inside of the cover portion and a fourth end on the outside of the cover portion. Each of the plurality of first ribs is inclined such that the first end is closer to the closed region than the second end. Each of the plurality of second ribs is inclined such that the third end is closer to the closed region than the fourth end. The image forming unit according to Appendix 8, characterized in that it is a product of the present invention. (Note 10) The image carrier is further disposed inside the cover portion. An image forming unit according to any one of the appendices 1 to 9, characterized in that it is the same as described in the appendix. (Note 11) The first vent, the closed area, and the second vent are arranged side by side in the longitudinal direction on the same surface that constitutes a part of the cover portion. A path is formed through which air flows from the first vent to the second vent, through the space inside the closed region. An image forming unit according to any one of the appendices 1 to 10, characterized in that it is the same as described in the appendix. (Note 12) An image forming unit as described in any one of the appendices 1 to 11, A housing that covers the image forming unit, An intake fan that sends outside air from the enclosure to the first vent, An image forming apparatus characterized by having the following features. (Note 13) The housing further includes an exhaust fan that discharges the air expelled from inside the cover through the second vent to the outside of the housing. The image forming apparatus according to Appendix 12, characterized in that it is a picture forming apparatus. (Note 14) An image forming unit as described in any one of the appendices 1 to 13, A light head unit that exposes the surface of the image carrier to form an electrostatic latent image, A holding portion is positioned opposite the cover portion and holds the optical head portion, The housing covers the image forming unit, the optical head, and the holding unit, An intake fan that draws air from outside the enclosure into the enclosure, It has, The aforementioned retaining part is A first opening through which the air sent into the housing flows, It has a second opening that directs the air flowing in from the first opening toward the first vent. An image forming apparatus characterized by the following features. (Note 15) The enclosure further includes an exhaust fan that discharges the air inside the enclosure to the outside. The aforementioned retaining part is A third opening is positioned opposite the second ventilation opening, It has a fourth opening through which the air that flows in from the third opening passes. The image forming apparatus according to Appendix 14, characterized in that it is a picture forming apparatus. (Note 16) A method for cooling an image forming unit performed by the image forming apparatus described in Appendix 13, The steps include: driving the intake fan that sends the air from outside the housing covering the image forming unit into the first vent; The steps include: driving the exhaust fan that discharges the air discharged from inside the cover through the second vent to the outside of the housing; A method for cooling an image forming unit, characterized by having the following features. (Note 17) A method for cooling an image forming unit performed by the image forming apparatus described in Appendix 15, The steps include: driving the intake fan that sends the air from outside the housing covering the image forming unit to the first opening of the holding part; The steps include: driving the exhaust fan which discharges the air that flows into the cover portion from the first vent through the first opening and the second opening, and is discharged from the cover portion through the second vent, to the outside of the housing; A method for cooling an image forming unit, characterized by having the following features. (Note 18) An image forming unit having a layer restricting member that restricts the thickness of the developer layer supported on a developer carrier that supplies developer to an image carrier, and a cover portion that covers the layer restricting member, A light head unit that exposes the surface of the image carrier to form an electrostatic latent image, A holding portion is positioned opposite the cover portion and holds the optical head portion, The housing covers the image forming unit, the optical head, and the holding unit, An intake fan that draws air from outside the enclosure into the enclosure, It has, The layer restricting member has one end in the longitudinal direction of the layer restricting member, and the other end on the opposite side of the one end in the longitudinal direction. The aforementioned cover portion is It extends in the longitudinal direction and has a ventilation opening facing the layer restricting member, The aforementioned retaining part is A first opening through which the air sent into the housing flows, A second opening that directs the air flowing in from the first opening toward the one end through the vent, A third opening is positioned opposite the other end via the aforementioned ventilation opening, A fourth opening through which the air flowing in from the third opening passes, has An image forming apparatus characterized by the following features. [Explanation of Symbols]

[0075] 1, 2 Image forming apparatus, 1a Housing, 1b Upper cover (cover member), 1c Media outlet, 1d Support shaft, 1e Stacker, 10, 10a Image forming unit (ID unit), 11 Photoreceptor drum (image carrier), 12 Charging roller (charging member), 13 Toner supply roller (developer supply member), 14 Developer roller (developer carrier), 15 Layer regulating member, 15a Developer blade, 15b Support member, 15aa Fixed end, 15ab Front end contact part, 15ba~15bb Rigid member, 16 Cleaning blade (cleaning member), 17 Toner cartridge (developer container), 18 Waste toner container, 20, 20a Cover part, 21 First ventilation port, 21a First slit, 21b 21ba First rib, 21bb First end, 22 Second end, 22a Second slit, 22b First rib, 22ba Third end, 22bb Fourth end, 23 Blocked area, 26a~26g Airflow, 27, 27a Wall section, 28 Vent, 30 Media cassette, 40 Media supply section, 41 Pickup roller, 42 Paper feed roller, 43 Separation roller, 44 Resist roller, 45 Pressure roller, 46 Transport roller pair, 50 Transfer unit, 60, 60a Exposure unit, 61 Head holder (holding section), 62 LED head (light head section), 63 First opening, 64 Second opening, 65 Third opening, 66 Fourth opening, 68 Wall section, 70 Fixing unit, 71 Fixing roller, 72 Pressure roller, 73 Duct, 74 Open space, 80 Media discharge section, 81, 82 Discharge roller pair, 90 Return transport section, 91 Switching guide (transport path switching section), 92, 93, 94 Transport roller pair, 110 Intake fan, 111 Intake port, 120 Exhaust fan, 121 Exhaust port, M Media, R1, R2, R3 Media transport path, R4 Media transport path (return transport path).

Claims

1. A layer restricting member that restricts the thickness of the developer layer supported on a developer carrier that supplies the developer to an image carrier, A cover portion that covers the layer restricting member, In an image forming unit having, The layer restricting member has one end in the longitudinal direction of the layer restricting member, and the other end on the opposite side of the one end in the longitudinal direction. The aforementioned cover portion is On the side of the other end toward the one end, a first ventilation opening facing the layer restricting member is provided, A second ventilation opening facing the layer restricting member is located on the other end side from the one end, Between the first vent and the second vent, there is a closed region spaced apart from the layer restricting member and facing the layer restricting member, has An image forming unit characterized by the following features.

2. The cover portion has a wall portion that extends in the longitudinal direction and faces at least a part of the layer restricting member, The wall portion has the first ventilation opening, the second ventilation opening, and the closed region. The image forming unit according to feature 1.

3. A space is formed between the wall surface and the layer restricting member. The first vent and the second vent communicate with the space. The image forming unit according to claim 2.

4. The aforementioned layer restricting member is A developing blade facing the surface of the developer carrier, A support member attached to the cover portion to support the developing blade, It has, The first vent and the second vent are separated from the support member and face each other across the space. The image forming unit according to feature 3.

5. The developing blade and the support member are made of metal. The image forming unit according to feature 4.

6. The first vent has a plurality of first ribs arranged in the longitudinal direction, The second ventilation opening has a plurality of second ribs arranged in the longitudinal direction, A first slit is formed on both sides of the longitudinal direction of each of the plurality of first ribs. A second slit is formed on both sides of each of the plurality of second ribs in the longitudinal direction. The image forming unit according to feature 4.

7. Each of the plurality of first ribs has a first end on the inside of the cover portion and a second end on the outside of the cover portion. Each of the plurality of second ribs has a third end on the inside of the cover portion and a fourth end on the outside of the cover portion. Each of the plurality of first ribs is inclined such that the first end is closer to the closed region than the second end. Each of the plurality of second ribs is inclined such that the third end is closer to the closed region than the fourth end. The image forming unit according to feature 6.

8. A developer carrier that carries the developer supplied to the image carrier, A cover portion that covers the developer carrier, In an image forming unit having, The developer carrier has one end in the longitudinal direction of the developer carrier, and the other end on the opposite side of the one end in the longitudinal direction. The aforementioned cover portion is A first vent facing the developer carrier is located on the side of the other end that is closer to the one end, A second vent facing the developer carrier is located on the other end side from the one end, Between the first vent and the second vent, there is a closed region that is spaced apart from the developer carrier and facing the developer carrier, has An image forming unit characterized by the following features.

9. The first vent and the second vent are separated by a space and face the developer carrier. The image forming unit according to feature 8.

10. The first vent has a plurality of first ribs arranged in the longitudinal direction, The second ventilation opening has a plurality of second ribs arranged in the longitudinal direction, A first slit is formed on both sides of the longitudinal direction of each of the plurality of first ribs. A second slit is formed on both sides of each of the plurality of second ribs in the longitudinal direction. The image forming unit according to feature 9.

11. Each of the plurality of first ribs has a first end on the inside of the cover portion and a second end on the outside of the cover portion. Each of the plurality of second ribs has a third end on the inside of the cover portion and a fourth end on the outside of the cover portion. Each of the plurality of first ribs is inclined such that the first end is closer to the closed region than the second end. Each of the plurality of second ribs is inclined such that the third end is closer to the closed region than the fourth end. The image forming unit according to feature 10.

12. The image carrier is further disposed inside the cover portion. The image forming unit according to any one of claims 1 to 11.

13. The first vent, the closed area, and the second vent are arranged side by side in the longitudinal direction on the same surface that constitutes a part of the cover portion. A path is formed through which air flows from the first vent to the second vent, through the space inside the closed region. The image forming unit according to any one of claims 4 or 9.

14. An image forming unit according to any one of claims 1 to 11, A housing that covers the image forming unit, An intake fan that sends outside air from the enclosure to the first vent, An image forming apparatus characterized by having the following features.

15. The housing further includes an exhaust fan that discharges the air expelled from inside the cover through the second vent to the outside of the housing. The image forming apparatus according to feature 14.

16. An image forming unit according to any one of claims 1 to 11, A light head unit that exposes the surface of the image carrier to form an electrostatic latent image, A holding portion is positioned opposite the cover portion and holds the optical head portion, The housing covers the image forming unit, the optical head, and the holding unit, An intake fan that draws air from outside the enclosure into the enclosure, It has, The aforementioned retaining part is A first opening through which the air sent into the housing flows, It has a second opening that directs the air flowing in from the first opening toward the first vent. An image forming apparatus characterized by the following:

17. The enclosure further includes an exhaust fan that discharges the air inside the enclosure to the outside. The aforementioned retaining part is A third opening is positioned opposite the second ventilation opening, It has a fourth opening through which the air that flows in from the third opening passes. The image forming apparatus according to feature 16.

18. A method for cooling an image forming unit carried out by an image forming apparatus according to claim 15, The steps include: driving the intake fan that sends the air from outside the housing covering the image forming unit into the first vent; The steps include: driving the exhaust fan that discharges the air discharged from inside the cover through the second vent to the outside of the housing; A method for cooling an image forming unit, characterized by having the following features.

19. A method for cooling an image forming unit carried out by an image forming apparatus according to claim 17, The steps include: driving the intake fan that sends the air from outside the housing covering the image forming unit to the first opening of the holding part; The steps include: driving the exhaust fan which discharges the air that flows into the cover portion from the first vent through the first opening and the second opening, and is discharged from the cover portion through the second vent, to the outside of the housing; A method for cooling an image forming unit, characterized by having the following features.

20. An image forming unit having a layer restricting member that restricts the thickness of the developer layer supported on a developer carrier that supplies developer to an image carrier, and a cover portion that covers the layer restricting member, A light head unit that exposes the surface of the image carrier to form an electrostatic latent image, A holding portion is positioned opposite the cover portion and holds the optical head portion, The housing covers the image forming unit, the optical head, and the holding unit, An intake fan that draws air from outside the enclosure into the enclosure, It has, The layer restricting member has one end in the longitudinal direction of the layer restricting member, and the other end on the opposite side of the one end in the longitudinal direction. The aforementioned cover portion is It extends in the longitudinal direction and has a ventilation opening facing the layer restricting member, The aforementioned retaining part is A first opening through which the air sent into the housing flows, A second opening that directs the air flowing in from the first opening toward the one end through the vent, A third opening is positioned opposite the other end via the aforementioned ventilation opening, A fourth opening through which the air flowing in from the third opening passes, has An image forming apparatus characterized by the following:

Images