JP2016033622A - Image formation apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress the increase of the temperature of a light source due to the air heated by a fixation part.SOLUTION: An image formation apparatus includes in a housing: an image formation part which has a photoreceptor; a fixation part which is provided having a constant interval with the photoreceptor in a horizontal direction orthogonal to a rotation axis direction of the photoreceptor and has a heating part; a light source; a light guide part which has a reception part for receiving light from the light source and is configured to guide the light received from the reception part to the surface of the photoreceptor; a fan which exhausts the air in the housing to the outside; and a shield wall. The light source is provided between the photoreceptor and the fixation part in the horizontal direction and provided so as to face the reception part on the inner side with respect to both ends of the image formation part in the rotation axis direction. The shield wall shields the fixation part side of the light source and is arranged at a position apart from the light source. The reception part is arranged so as to face the light source on the inner side with respect to both ends of the image formation part in the rotation axis direction. A ventilation trunk connected with the fan is formed between the light source and the shield wall.SELECTED DRAWING: Figure 6

Description

  The technology disclosed in this specification relates to an image forming apparatus.

  2. Description of the Related Art Conventionally, there is known an electrophotographic image forming apparatus that forms an image on a sheet by charging a photosensitive drum to form a toner image, transferring the toner image to a sheet, and then thermally fixing the toner image on a fixing unit. Yes. Among such image forming apparatuses, there is an image forming apparatus that includes a static eliminator that removes charges remaining on a photosensitive drum (for example, Patent Document 1). The static eliminator is accommodated in a unit that holds the photosensitive drum and extends in the direction of the rotation axis of the photosensitive drum, and is disposed outside the both ends of the unit in the direction of the rotation axis. And a light source disposed opposite to one end. The light source emits light toward one end of the light guide unit, and the light guide unit discharges the photosensitive drum by irradiating the surface of the photosensitive drum with light incident from the one end.

JP 2011-227425 A

  In the image forming apparatus, in order to reduce the size of the apparatus, the position of the light source is changed from the position outside the both ends of the image forming unit such as the unit in the rotation axis direction to the inside position with respect to the conventional configuration. Can be considered. However, in the configuration after the change, the light source is disposed at a position closer to the fixing unit than in the conventional configuration, and the temperature of the light source is increased by the air heated by the fixing unit. There is a problem that it is promoted and easily causes failure of the light source.

  The present specification discloses a technique capable of solving at least a part of the above-described problems.

(1) An image forming apparatus disclosed in the present specification is an electrophotographic image forming apparatus, and includes an enclosure and a photoconductor that is provided in the enclosure and rotates around a rotation axis. A fixing unit provided in the casing at a predetermined interval in a horizontal direction perpendicular to the rotation axis direction of the photosensitive member, having a heating unit, a light source provided in the casing, A light guide portion provided in the housing, having a receiving portion for receiving light from the light source, and configured to guide the light received from the receiving portion to the surface of the photoreceptor; A fan for discharging air to the outside, and a shielding wall provided in the housing, wherein the light source is provided between the photosensitive member and the fixing unit in the horizontal direction, and is in the direction of the rotation axis In front of both ends of the image forming unit The shielding wall is provided facing the receiving portion, the shielding wall shields the fixing portion side of the light source and is disposed at a position away from the light source, and the receiving portion forms the image in the rotation axis direction. An air passage that is connected to the fan is formed between the light source and the shielding wall. In this image forming apparatus, the light source is provided between the photoconductor and the fixing unit in the horizontal direction, and is provided inside the both ends of the image forming unit in the rotation axis direction of the photoconductor. The light guide unit has a receiving unit for receiving light from the light source, and is configured to guide the light received from the receiving unit to the surface of the photoreceptor. The receiving part is located inside the both ends of the image forming part in the rotation axis direction. Therefore, the size of the image forming apparatus in the rotation axis direction can be reduced as compared with the conventional configuration in which the light source is arranged outside both ends of the image forming unit in the rotation axis direction. In such an image forming apparatus, the light source is disposed closer to the fixing unit than in the conventional configuration. However, since this image forming apparatus has a shielding wall that shields the fixing portion side of the light source, air heated by the fixing portion can be prevented from reaching the light source as compared with the case where there is no shielding wall. In addition, since the light source and the shielding wall are arranged apart from each other and a ventilation path connected to the fan is formed between the light source and the shielding wall, the air heated by the fixing unit is caused by the flow of air flowing through the ventilation path. It does not stay around. Accordingly, it is possible to suppress the temperature rise of the light source due to the air warmed by the fixing unit while reducing the size of the apparatus.

(2) In the image forming apparatus, the light source has an emission port that emits light, and further includes a hole that accommodates at least a portion of the light source except the emission port and opens the emission port. A cover body, wherein the cover body includes the shielding wall as a part of the cover body, and an inflow hole and an outflow hole are formed in a portion excluding the shielding wall of the cover body, An air passage connected to the fan is formed between the light source and the shielding wall via the inflow hole and the outflow hole, provided on the side of the cover body where the outflow hole is formed. It is good also as a structure. According to this image forming apparatus, since the cover body that accommodates at least a portion of the light source excluding the emission port is provided, air heated by the fixing unit reaches the light source as compared with the case where the cover body is not provided. Can be suppressed. In addition, an inflow hole and an outflow hole are formed in a portion excluding the shielding wall of the cover body, and a fan is provided on the side where the outflow hole of the cover body is formed, thereby constituting a part of the cover body. A ventilation path connected to the fan is formed between the shielding wall and the light source. Thereby, the temperature rise of the light source by the air warmed by the fixing unit can be suppressed.

(3) In the image forming apparatus, the inflow hole is formed in a lower surface of the cover body, the outflow hole is formed in an upper surface of the cover body, and the fan is disposed above the cover body. It is good also as composition which has. According to this image forming apparatus, since the inflow hole, the outflow hole, and the fan are arranged side by side in the vertical direction of the cover body, compared to the case where they are not arranged in a predetermined direction including the vertical direction, It is easy to create a flow of air that leads to the fans. Further, since the fan is disposed above the cover body, an upward air flow is generated in the cover body. Therefore, compared with the case where a downdraft is generated in the cover body, it is possible to suppress the toner and paper powder from entering the cover body, and it is possible to suppress the reduction of the charge removal capability due to the contamination of the light source.

(4) In the image forming apparatus, the fan is provided on a side surface of the casing on one end side of both ends of the image forming unit in the rotation axis direction, and the light guide unit extends in the rotation axis direction. A first light guide portion disposed opposite to the photosensitive member; and a first light guide portion extending from one end of the first light guide portion in a direction orthogonal to the rotation axis direction, and a leading end portion in the extending direction is the receiving portion The light source and the receiving unit may be provided on one end side where the fan is provided on both ends of the image forming unit. According to this image forming apparatus, the fan, the light source, and the receiving unit are provided on one end side of both ends of the image forming unit, and it is easy to create an air flow connected to the fan. Compared with the case where the fan and the light source are provided on different end sides, it is easy to discharge the air near the light source to the outside using the fan. Thereby, the temperature rise of the light source by the air warmed by the fixing unit can be suppressed.

(5) In the image forming apparatus, a guide member that is provided between the image forming unit and the fixing unit in the housing and guides a sheet from the image forming unit side to the fixing unit side. The guide member is provided with a plurality of communication holes connected to the outside of the housing, and the cover body is connected to the guide member so that one of the plurality of communication holes is connected to the inflow hole. It is good also as a structure provided in. According to this image forming apparatus, the guide member for guiding the sheet from the image forming unit to the fixing unit is provided, and the guide member is provided with a plurality of communication holes connected to the outside of the housing. Since one of the plurality of communication holes provided in the guide member is connected to the inflow hole, air from the outside of the housing can easily flow into the cover body, thereby suppressing an increase in the temperature of the light source. .

(6) In the image forming apparatus, the second light guide portion extends obliquely downward from the one end portion of the first light guide portion in a direction orthogonal to the rotation axis direction, and the light source includes the second light source. It is good also as a structure which the light guide part opposes the said receiving part which is the edge part extended in the said slanting downward, and is arrange | positioned outside the conveyance path | route of the sheet | seat on the said guide member. Since the light source is provided obliquely below the photoconductor, an image forming apparatus that is smaller in the horizontal direction can be configured than when the light source is provided directly beside the photoconductor. Further, since the light source is provided outside the sheet conveyance path on the guide member, the sheet can be conveyed without being obstructed by the light source.

(7) In the image forming apparatus, the image forming apparatus further includes a partition wall having a lower end positioned above the outflow hole and an upper end positioned at a position up to the fan. It is good also as a structure which has a partition wall extended from the said lower end to the said upper end over the both ends of a part. According to this image forming apparatus, it is possible to form a ventilation path connected from the communication hole and the outflow hole to the fan by the partition wall.

(8) In the image forming apparatus, the image forming unit may be a process cartridge that can be attached to and detached from the casing, and the process cartridge may include the light guide unit. According to this image forming apparatus, the light source is provided inside the both ends of the process cartridge in the direction of the rotation axis of the photosensitive member, and the receiving portion is positioned inside the both ends of the process cartridge in the direction of the rotation axis of the photosensitive member. Compared to the conventional configuration, the size of the image forming apparatus in the rotation axis direction can be reduced.

(9) In the image forming apparatus, an opening area of the outflow hole may be smaller than an opening area of the inflow hole. According to this image forming apparatus, since the opening area of the outflow hole is smaller than the opening area of the inflow hole, the flow velocity of air flowing out from the outflow hole can be improved more than the flow velocity of air flowing into the inflow hole. Thereby, it is possible to prevent toner and paper dust from entering the cover body from the outflow hole formed in the upper surface of the cover body.

(10) The image forming apparatus may further include a substrate connected to the light source, and a transmission substrate that transmits an electric signal to the substrate, the substrate being provided on the fixing unit side with respect to the light source. The harness connecting the board and the transmission board may be arranged via the inflow hole. According to this image forming apparatus, by being arranged via the inflow hole, the path through which the harness passes and the ventilation path are combined, and there is no need to separately provide a path through which the harness passes.

  Note that the technology disclosed in this specification can be realized in various forms, for example, in the form of a static eliminator, a light emitting device that emits light for static elimination, and the like. .

Sectional drawing of the printer which concerns on one Embodiment Photosensitive drum, guide member, light guide, and EL perspective view Schematic top view of photosensitive drum, light guide, EL, and fixing unit Perspective view of EL, support wall, guide member, air duct, and fixing unit Perspective view of photosensitive drum, support wall, guide member, air duct, and fixing unit Expanded sectional view of EL and guide member The figure which shows the position of the board and the main board in the housing EL perspective view Enlarged perspective view around the support portion of the guide member

  A printer 1 according to an embodiment will be described with reference to FIGS. The printer 1 is a monochrome laser printer that forms an image using a single color (for example, black) toner. The printer 1 is an example of an electrophotographic image forming apparatus. In the following description, the right side of FIG. 1 is the front side F of the printer 1, the back side of the paper is the right side R of the printer 1, and the upper side of the paper is the upper side U of the printer 1.

  The printer 1 includes a housing 2, and the housing 2 includes a sheet supply unit 3, a scanner unit 5, a process cartridge 6, a fixing unit 7, a guide member 15, and a discharge roller 30. .

  The casing 2 has a substantially rectangular parallelepiped shape as a whole, and an opening 2C is formed on the front surface. A front cover 2A is disposed so as to close the opening 2C. Since the lower end portion of the front cover 2A is supported by the housing 2 so as to be rotatable about a rotation axis parallel to the left-right direction, the front cover 2A has a closed position (see FIG. 1) that closes the opening 2C; It can be displaced to an open position (not shown) that opens the opening 2C. A discharge port 10C is formed on the upper surface of the housing 2, and a discharge tray 10B is formed in front of the discharge port 10C.

  The sheet supply unit 3 is disposed in the lower part of the housing 2 and includes a supply tray 10 </ b> A, a pressing plate 11, a supply roller 12, a conveyance roller 13, and a registration roller 14. The supply tray 10 </ b> A can store a plurality of sheets S and is configured to be able to be pulled out to the front side F of the printer 1 with respect to the housing 2. The pressing plate 11 presses the sheet S stored in the supply tray 10A upward. The supply roller 12 is disposed above the supply tray 10A, contacts the sheet S pressed by the pressing plate 11, and rotates to feed the sheet S forward.

  The conveyance roller 13 is disposed obliquely upward on the front side of the supply roller 12 and conveys the sheet S sent from the supply tray 10A to the registration roller 14 side. The registration roller 14 is disposed obliquely upward on the rear side of the conveyance roller 13, and corrects the sheet S conveyed so as to be folded back in a U shape via the conveyance roller 13 to the process cartridge 6 side. Transport. Note that a solid line H in FIG. 1 indicates the conveyance path of the sheet S from the supply tray 10A to the discharge tray 10B.

  The scanner unit 5 is disposed in the upper space in the housing 2, and emits laser light L <b> 1 by a polygon scanning method to a charged portion of the photosensitive drum 23 described later, and exposes the charged portion of the photosensitive drum 23. To do. The process cartridge 6 is disposed between the sheet supply unit 3 and the scanner unit 5. The process cartridge 6 is an example of an image forming unit, and includes a frame 28. In the frame 28, a toner storage unit 20, a developing roller 22, a photosensitive drum 23, a charging unit 25, a transfer roller 24, and the like. The cleaning roller 27 and a light guide unit 61 to be described later are provided. The photosensitive drum 23 is an example of a photoconductor.

  The photosensitive drum 23 is cylindrical and has a photosensitive layer formed on the surface. The photosensitive drum 23 has a rotating shaft body 23A parallel to the left-right direction, and is supported by the frame 28 so as to be rotatable about the rotating shaft body 23A. Hereinafter, the direction of the rotating shaft body 23 </ b> A may be referred to as the rotating shaft direction of the photosensitive drum 23.

  The charging unit 25 is disposed above the photosensitive drum 23 and charges the charging position Y <b> 2 facing the charging unit 25 on the surface of the photosensitive drum 23. When the charged portion of the photosensitive drum 23 is exposed by the scanner unit 5, an electrostatic latent image is formed on the surface of the photosensitive drum 23. The developing roller 22 is disposed on the front side of the photosensitive drum 23 and supplies toner stored in the toner storage unit 20 to the electrostatic latent image on the photosensitive drum 23. As a result, a toner image is formed on the surface of the photosensitive drum 23.

  The transfer roller 24 is disposed at a position facing the photosensitive drum 23 via the conveyance path H of the sheet S. The sheet S conveyed by the registration roller 14 passes through a transfer position Y1 where the photosensitive drum 23 and the transfer roller 24 face each other. The transfer roller 24 transfers the toner image on the photosensitive drum 23 to the sheet S at the transfer position Y1 by electrostatic force. The cleaning roller 27 collects deposits such as toner and paper powder remaining on the surface of the photosensitive drum 23 after the static elimination by the light guide unit 61 and before being charged again by the charging unit 25.

  The fixing unit 7 is provided at a predetermined interval from the photosensitive drum 23 in a direction orthogonal to the rotation axis direction of the photosensitive drum 23. The direction orthogonal to the rotation axis direction of the photosensitive drum 23 is an example of the horizontal direction. Specifically, the fixing unit 7 is disposed behind the photosensitive drum 23 and on the downstream side of the photosensitive drum 23 in the conveyance path H. The sheet S on which the toner image is transferred is transferred to the registration roller 14 and the registration roller 14. The photosensitive drum 23 and the like are conveyed from the photosensitive drum 23 side to the fixing unit 7 side. The fixing unit 7 includes a heating unit 7A having a heater inside, and a pressure roller 7B disposed to face the heating unit 7A, and applies the sheet S on which the toner image is transferred while heating the sheet S by the heating unit 7A. The toner image is conveyed and fixed on the sheet S by the pressure roller 7B. The sheet S on which the toner image has been thermally fixed is discharged onto the discharge tray 10B by the discharge roller 30.

  The guide member 15 is provided between the process cartridge 6 and the fixing unit 7 in the front-rear direction of the printer 1 and guides the sheet S from the process cartridge 6 side to the fixing unit 7 side. Specifically, as shown in FIG. 2, the guide member 15 has a substantially flat plate shape as a whole. The left and right ends of the guide member 15 are disposed so as to be positioned at substantially the same positions as the left and right ends of the photosensitive drum 23 or on the outer sides of the left and right ends of the photosensitive drum 23 in the rotation axis direction of the photosensitive drum 23.

  A plurality of ribs 15 </ b> C for guiding the sheet S are provided on the upper surface 15 </ b> B of the guide member 15 so as to be arranged at intervals in the rotation axis direction of the photosensitive drum 23. The upper end portion of each rib 15C is lowered as it goes from the process cartridge 6 side toward the fixing portion 7 side, and is curved so as to increase from the middle. As will be described later, the guide member 15 is formed with a plurality of communication holes 15D for ventilating the inside of the housing 2. The plurality of communication holes 15D are formed at positions between the ribs 15C and at positions outside the ribs 15C located at both left and right ends (see FIG. 6). Further, a support portion 16 for supporting an erase laser (hereinafter referred to as “EL”) 8 described later is provided at one end (right end in FIG. 2) of the guide member 15 in the left-right direction. The detailed structure of the support portion 16 will be described later.

  The process cartridge 6 is detachably attached to the housing 2. By setting the front cover 2 </ b> A to the open position, the process cartridge 6 can be taken in and out from the opening 2 </ b> C of the housing 2. Specifically, a pair of support walls 2B are provided in the housing 2, and the pair of support walls 2B sandwich the process cartridge 6 and the fixing unit 7 as shown in FIG. Are arranged to face each other in the left-right direction. As shown in FIG. 5, the support wall 2B disposed on the right side of the pair of support walls 2B has the right end portion of the rotating shaft 23A of the photosensitive drum 23 from the opening 2C side to the guide member 15 side. Ribs 2F for guiding are formed. Similarly, although not shown, a rib 2F for guiding the left end portion of the rotating shaft 23A of the photosensitive drum 23 from the opening 2C side to the guide member 15 side is provided on the support wall 2B disposed on the left side. Is formed.

  In order to mount the process cartridge 6 in the housing 2, as shown in FIG. 3, both ends of the rotating shaft 23A of the photosensitive drum 23 are supported by the ribs 2F of the pair of support walls 2B, respectively. 6 is pushed into the inner side of the housing 2.

  The printer 1 further includes a fan 9 and a partition wall 18, and can discharge the air heated by the fixing unit 7 to the outside of the housing 2. Specifically, as shown in FIG. 1, the fan 9 is provided on the side surface 2D of the support wall 2B located on the right side, and rotates to discharge the air in the housing 2 to the outside. The side surface 2D is an example of a side surface of the casing on one end side of both ends of the image forming unit. The fan 9 is disposed so as to be positioned above the communication hole 15D located on the rightmost side among the plurality of communication holes 15D formed in the guide member 15.

  As shown in FIG. 4, the partition wall 18 has a flat plate shape extending in the left-right direction as a whole. The partition wall 18 forms an air duct with a wall (not shown) disposed with a gap in front of the partition wall 18 (see FIG. 1). The lower end of the partition wall 18 is disposed at a position above the plurality of communication holes 15D of the guide member 15, and the upper end of the partition wall 18 is disposed at a position reaching the fan 9. Or extending from the lower end to the upper end over the entire length of the fixing unit 7. Thereby, the partition wall 18 partitions the space between the process cartridge 6 and the fixing unit 7 (see FIG. 1).

  Between the guide member 15 and the supply tray 10 </ b> A, for example, a structure 19 such as a reversing guide for double-sided printing is disposed, and a hole 19 </ b> A is formed through the structure 19. A gap 2G is secured between the rear end of the supply tray 10A and the rear surface of the housing 2. With the above configuration, as shown by the dotted arrow in FIG. 1, the housing 2 is formed from the gap 2 </ b> G by the hole 19 </ b> A of the structure 19, the communication hole 15 </ b> D formed in the guide member 15, and the partition wall 18. A ventilation path T connected to the outside is formed through the air duct and the fan 9, and the air heated by the fixing unit 7 can be discharged to the outside of the housing 2 by the ventilation path T. it can.

  The printer 1 further includes a light guide unit 61 and an EL 8. The printer 1 can remove charges remaining on the surface of the photosensitive drum 23 after the transfer of the toner image, that is, can remove electricity.

  The light guide unit 61 includes a receiving unit 66 for receiving light from the EL 8, and is configured to guide the light received from the receiving unit 66 to the surface of the photosensitive drum 23. As described above, the light guide 61 is provided in the process cartridge 6 (see FIG. 1). The light guide 61 is made of, for example, a colorless and transparent acrylic resin, and includes a first light guide 62 and a second light guide 63. Each of the first light guide 62 and the second light guide 63 has a columnar shape, and both ends thereof are connected so as to be substantially orthogonal to each other. As shown in FIG. Here, “substantially orthogonal” is not limited to 90 degrees, and the angle formed by the axial direction of the first light guide 62 and the axial direction of the second light guide 63 is, for example, an angle range from 80 ° to 100 °. It is also included in the case.

  The first light guide unit 62 extends in the direction of the rotation axis of the photosensitive drum 23 and is disposed to face the photosensitive drum 23. Specifically, as shown in FIG. 1, the first light guide unit 62 is disposed between the photosensitive drum 23 and the fixing unit 7, and in the rotation direction X of the photosensitive drum 23 on the surface of the photosensitive drum 23. It faces the position between the transfer position Y1 and the charging position Y2. The first light guide 62 is formed in a substantially D-shaped cross section, the front surface 64 facing the photosensitive drum 23 has an arc shape in cross section, and the rear surface 65 is a flat surface. The light received by the receiving unit 66 and guided by the second light guide unit 63 is reflected by the rear surface 65 of the first light guide unit 62 toward the front surface 64 and is irradiated on the surface of the photosensitive drum 23.

  As shown in FIG. 3, the length of the first light guide unit 62 in the left-right direction is slightly shorter than that of the photosensitive drum 23, and both ends of the first light guide unit 62 are positioned at the photosensitive drum 23 in the rotation axis direction of the photosensitive drum 23. 23 is located outside both ends of the transfer region R1. The transfer region R <b> 1 is a region through which the maximum size sheet S that can be formed by the printer 1 in the photosensitive drum 23 passes and is used for image formation on the sheet S. In the photosensitive drum 23, the non-transfer areas R2 positioned on the left and right sides of the transfer area R1 are areas where the sheet S does not pass and are not used for image formation on the sheet S.

  As shown in FIG. 2, the second light guide portion 63 extends obliquely downward and rearward from the right end portion of the first light guide portion 62, and the leading end portion in the extending direction becomes the receiving portion 66. Further, as shown in FIG. 3, the receiving portion 66 is disposed inside the both ends 28A and 28B of the frame 28 of the process cartridge 6 in the rotation axis direction of the photosensitive drum 23, and among these both ends 28A and 28B, Are arranged on the right end 28A side. More specifically, the second light guide unit 63 is disposed behind the outer region R3 on the right side of the process cartridge 6, and the receiving unit 66 is disposed so as to face the light emitting unit 41 of the EL 8 described later. Yes.

  The receiving unit 66 functions as an incident surface that receives light from the EL 8. The light received by the receiving unit 66 is internally reflected in the direction of the rotation axis of the photosensitive drum 23 by the reflecting surface 67 of the connection portion between the first light guide unit 62 and the second light guide unit 63, and thereby the second light guide. Guided into part 63.

  The EL 8 is provided between the photosensitive drum 23 and the fixing unit 7 in the front-rear direction, and is disposed on the inner side of both ends of the process cartridge 6 in the rotation axis direction of the photosensitive drum 23, and the receiving unit 66 of the light guide unit 61. Is facing. In other words, the EL 8 is the same as the photosensitive drum 23 when viewed from the direction (vertical direction) perpendicular to both the alignment direction (horizontal direction) of the photosensitive drum 23 and the fixing unit 7 and the rotation axis direction of the photosensitive drum 23. It is located between the fixing unit 7 and inside the both ends of the process cartridge 6. Specifically, the EL 8 is disposed at a position obliquely below the second light guide part 63 of the light guide part 61 (see FIG. 2), and emits light toward the receiving part 66 located obliquely above the front side. Exit. As shown in FIG. 6 which shows the AA cross section of FIG. 2, EL8 is equipped with the light emission part 41, the board | substrate 42, and the resin-made cover bodies 51. As shown in FIG. The light emitting unit 41 is an example of a light source.

  The light emitting unit 41 includes an LED (light emitting diode) element 43 and a lens member 47. The LED element 43 is mounted on the upper surface 42 </ b> A of the substrate 42 so that the receiving part 66 of the light guide part 61 is positioned on the optical axis Z of the LED element 43. The lens member 47 has a cylindrical shape as a whole, and an emission lens 47A is provided on the distal end side in the direction of the optical axis Z, and the proximal end side is fixed to the substrate 42. The exit lens 47 </ b> A collects the light emitted from the LED element 43 and causes the light to enter the receiving portion 66 of the light guide portion 61. The tip of the lens member 47 on the exit lens 47 </ b> A side is the exit port 44.

  The substrate 42 is provided on the fixing unit 7 side with respect to the light emitting unit 41. Specifically, the substrate 42 is located on the rear side of the light emitting unit 41 and is disposed in an inclined posture with its upper surface 42A directed obliquely upward on the front side. 42 is electrically connected to the LED element 43. Further, as shown in FIG. 7, the board 42 is electrically connected to a main board 45 disposed on the left side in the housing 2 by a harness 46. The board 42 receives an electric signal for lighting the LED element 43 from the main board 45, and lights the LED element 43 based on the electric signal. The main board 45 is an example of a transmission board.

  The cover body 51 accommodates at least a portion of the light emitting unit 41 excluding the emission port 44, and has a hole 54 that opens the emission port 44 of the light emission unit 41. That is, in the light emitting portion 41, the portion of the emission port 44 is exposed to the outside through the hole 54, and the portion other than the emission port 44 is covered with the cover body 51.

  Specifically, the cover body 51 has a substantially rectangular parallelepiped shape as a whole, and includes a light emission support portion 52 and a shielding wall 53. The light emission support part 52 is an example of the part except the shielding wall of a cover body. The light emission support portion 52 is made of, for example, ABS resin, has a box-like shape with an open rear end side, and the hole 54 described above is formed through the front upper portion thereof. Further, as shown in FIG. 8, an outflow hole 55 is formed on the upper surface 52 </ b> A of the light emission support portion 52, and an inflow hole 56 is formed on the lower surface 52 </ b> B of the light emission support portion 52. Further, as shown in FIG. 8, the opening area of the outflow hole 55 is formed smaller than the opening area of the inflow hole 56.

  The shielding wall 53 shields the fixing unit 7 side of the light emitting unit 41 and is disposed at a position away from the light emitting unit 41 and the substrate 42 toward the fixing unit 7 side. Specifically, the shielding wall 53 is disposed so as to cover the rear end side of the light emission support portion 52. In other words, the shielding wall 53 is disposed between the fixing unit 7 and the light emitting unit 41 so as to hide the light emitting unit 41 behind when viewed from the fixing unit 7 side. The shielding wall 53 is made of, for example, a polycarbonate resin having higher heat resistance than the ABS resin, and has heat resistance higher than that of the light emitting support portion 52. The shielding wall 53 is provided with an insertion portion 57 that is inserted into the support hole 17 provided in the support portion 16 of the guide member 15 (see FIGS. 6 and 8).

  The EL 8 is disposed on the ventilation path T for discharging the air heated by the fixing unit 7 to the outside of the housing 2. Specifically, a support portion 16 for supporting an EL 8 described later is provided in a portion of the guide member 15 where 15D located at the right end is formed (see FIG. 2). Therefore, EL8 is disposed at a position outside the transfer region R1 of the photosensitive drum 23 in the left-right direction.

  As shown in FIG. 9, the support portion 16 has a support hole 17 and a support surface 15 </ b> A located on the front side of the support hole 17. By inserting the insertion portion 57 of the shielding wall 53 into the support hole 17, the EL 8 is fixed to the guide member 15, and the lower surface 52B of the light emission support portion 52 is supported by the support surface 15A. The support surface 15A is formed with a right end communication hole 15D extending therethrough.

  As shown in FIG. 6, when the EL 8 is fixed to the support portion 16, the communication hole 15 </ b> D at the right end and the inflow hole 56 of the cover body 51 communicate with each other. Thus, in the cover body 51, the ventilation path T is formed between the light emitting unit 41 and the shielding wall 53 that are arranged apart from each other in the front-rear direction of the printer 1, and between the substrate 42 and the shielding wall 53. The As a result, the gap 19 </ b> G of the housing 2 is formed by the hole 19 </ b> A of the structure 19, the communication hole 15 </ b> D formed at the right end of the guide member 15, the inflow hole 56, the outflow hole 55, and the partition wall 18. A ventilation path T connected to the outside is formed via the air duct and the fan 9.

  Since such a ventilation path T is formed, when the fan 9 is driven, an air flow is generated in the ventilation path T from the gap 2G of the housing 2 to the fan 9, as shown in FIG. Along with this, an updraft is generated in the cover body 51 through the inflow hole 56 and the outflow hole 55.

  As shown in FIG. 7, the harness 46 that connects the board 42 and the main board 45 extends to the communication hole 15 </ b> D at the right end of the guide member 15, the inflow hole 56 of the cover body 51, and the lower side D of the guide member 15. It arrange | positions via the cavity 2H. The communication hole 15 </ b> D and the inflow hole 56 also serve as a hole for arranging the harness 46.

  As described above, in the printer 1 according to the present embodiment, the light emitting unit 41 is provided between the photosensitive drum 23 and the fixing unit 7 in the horizontal direction, and the frame 28 of the process cartridge 6 in the rotation axis direction of the photosensitive member. Are provided inside the both ends 28A, 28B. The light guide unit 61 includes a receiving unit 66 for receiving light from the light emitting unit 41, and is configured to guide the light received from the receiving unit 66 to the surface of the photosensitive drum 23. The receiving portion 66 is located inside both ends 28A and 28B of the frame 28 of the process cartridge 6 in the rotation axis direction. Therefore, as shown by a dotted line in FIG. 3, the light emitting portion 41 </ b> A has a printer in the rotational axis direction as compared with the conventional configuration in which the light emitting portion 41 </ b> A is disposed outside both ends 28 </ b> A and 28 </ b> B The size of 1 can be reduced.

  On the other hand, in such a printer 1, the light emitting unit 41 is disposed closer to the fixing unit 7 than in the conventional configuration. Since the printer 1 according to the present embodiment includes the shielding wall 53 that shields the fixing unit 7 side of the light emitting unit 41, the air heated by the fixing unit 7 reaches the light emitting unit 41 as compared to the case where the shielding wall 53 is not provided. This can be suppressed. Further, since the light emitting unit 41 and the shielding wall 53 are arranged apart from each other, and the ventilation path T connected to the fan is formed between the light emitting unit 41 and the shielding wall 53, the flow of air flowing through the ventilation path T Air heated by the fixing unit 7 does not stay around the light emitting unit 41. Accordingly, it is possible to suppress the temperature increase of the light source due to the air warmed by the fixing unit 7 while reducing the size of the printer 1.

  The printer 1 according to the present embodiment includes the cover body 51 that accommodates at least a portion of the light emitting unit 41 excluding the hole 54. Reaching the light emitting unit 41 can be suppressed. In addition, an inflow hole 56 and an outflow hole 55 are formed in the light emitting support portion 52 that is a portion excluding the shielding wall 53 of the cover body 51, and the upper side U in which the outflow hole 55 of the cover body 51 is formed in the fan 9. As a result, a ventilation path T connected to the fan 9 is formed between the shielding wall 53 constituting a part of the cover body 51 and the light emitting unit 41. Thereby, the temperature rise of the light emission part 41 by the air warmed by the fixing part 7 can be suppressed.

  In the printer 1 of the present embodiment, the inflow hole 56, the outflow hole 55, and the fan 9 are arranged side by side in the vertical direction of the cover body 51, and therefore they are not arranged in a predetermined direction including the vertical direction. Compared to the above, it is easier to create a flow of air connected to the fan 9. Further, since the fan 9 is disposed above the cover body 51, an upward air flow is generated in the cover body 51. Therefore, compared with the case where a downdraft is generated in the cover body 51, it is possible to suppress the toner and paper powder from entering the cover body 51 and to prevent the charge removal capability from being deteriorated due to contamination of the light emitting unit 41. it can.

  In the printer 1 of the present embodiment, the fan 9, the light emitting unit 41, and the receiving unit 66 are provided at one end common to both ends of the process cartridge 6, and an air flow connected to the fan 9 can be easily created. Compared with the case where the fan 9 and the light emitting unit 41 are provided on different end sides, the air near the light emitting unit 41 can be easily discharged to the outside using the fan 9. Thereby, the temperature rise of the light emission part 41 by the air warmed by the fixing part 7 can be suppressed.

  In the printer 1 of the present embodiment, a guide member 15 that guides the sheet S from the process cartridge 6 to the fixing unit 7 is provided, and the guide member 15 is provided with a plurality of communication holes 15D that are connected to the outside of the housing 2. Yes. Since one of the plurality of communication holes 15 </ b> D provided in the guide member 15 is connected to the inflow hole 56, air from the outside of the housing 2 easily flows into the cover body 51. Temperature rise can be suppressed.

  In the printer 1 of the present embodiment, since the light emitting unit 41 is provided obliquely below the photosensitive drum 23, the printer 1 that is smaller in the horizontal direction than when the light emitting unit 41 is provided directly beside the photosensitive drum 23. Can be configured. Further, since the light emitting unit 41 is provided outside the conveyance path H of the sheet S on the guide member 15, the sheet S can be conveyed without being obstructed by the light emitting unit 41.

  In the printer 1 of the present embodiment, the lower end of the partition wall 18 is disposed at a position above the plurality of communication holes 15 </ b> D of the guide member 15, and the upper end of the partition wall 18 is disposed at a position up to the fan 9. Therefore, the air duct formed by the partition wall 18 can form the ventilation path T connected from the communication hole 15 </ b> D and the outflow hole 55 to the fan 9.

  In the printer 1 of the present embodiment, the light emitting unit 41 is provided inside the both ends 28A and 28B of the frame 28 of the process cartridge 6 in the rotation axis direction of the photosensitive drum 23, and the receiving unit 66 is in the rotation axis direction of the photosensitive drum 23. Since the process cartridge 6 is positioned on the inner side of the both ends 28A and 28B of the frame 28, the size of the printer 1 in the direction of the rotation axis can be reduced as compared with the conventional configuration.

  In the printer 1 of the present embodiment, since the opening area of the outflow hole 55 is smaller than the opening area of the inflow hole 56, the flow velocity of the air flowing out from the outflow hole 55 is made higher than the flow velocity of the air flowing into the inflow hole 56. Can do. Thereby, it is possible to prevent toner and paper powder from entering the cover body from the outflow hole 55 formed on the upper surface of the cover body 51.

  In the printer 1 of this embodiment, by arranging the harness 46 that connects the board 42 and the main board 45 via the inflow hole 56, the path through which the harness 46 passes and the ventilation path T are combined. There is no need to provide a path through which the harness 46 passes.

  The technology disclosed in the present specification is not limited to the embodiments described with reference to the above description and drawings, and includes, for example, the following various aspects.

  In the above-described embodiment, the example in which the scanner unit 5 emits the laser beam L1 to the charged portion of the photosensitive drum 23 by the polygon scanning method is shown, but the present invention is not limited to this. For example, the scanner unit 5 includes a plurality of LED elements arranged in the direction of the rotation axis of the photosensitive drum 23, and the LED that emits light to the charged portion of the photosensitive drum 23 by sequentially emitting the plurality of LED elements. It may be a method.

  In the above embodiment, an example in which the transfer roller 24 is provided in the process cartridge 6 has been described. However, the present invention is not limited thereto, and the transfer roller 24 may be rotatably supported by the housing 2. Then, the process cartridge 6 detachably provided in the housing 2 may be mounted on the housing 2 so as to face the photosensitive drum 23 in the process cartridge 6.

  In the above-described embodiment, an example in which the process cartridge 6 includes the light guide unit 61 has been described. However, the present invention is not limited thereto, and the light guide unit 61 may be supported by the housing 2. Thereby, it can suppress that the relative position of the light emission part 41 and the light guide part 61 changes by attachment or detachment of the process cartridge 6, and a static elimination capability falls.

  In the above-described embodiment, an example in which the inflow hole 56 and the outflow hole 55 are formed in the lower surface 52B and the upper surface 52A of the light emitting support portion 52, respectively, the fan 9 is arranged side by side with the EL8 in the rotation axis direction, for example. In such a case, an inflow hole 56 and an outflow hole 55 may be formed on the right and left surfaces of the light emitting support 52, respectively. On the other hand, since the shielding wall 53 shields the portion of the light emitting unit 41 on the fixing unit 7 side, the inflow hole 56 and the outflow hole 55 are not formed in the shielding wall 53.

  In the above embodiment, an example in which the hole of the casing 2 through which the ventilation path T passes is the clearance 2G for clearance provided between the rear end of the supply tray 10A and the rear surface of the casing 2 is shown. Not limited to this, any hole formed in the housing 2 can be used.

  In the said embodiment, although the part other than the emission port 44 of the light emission part 41 was accommodated in the cover body 51, it was not restricted to this. For example, the entire light emitting unit 41 including the emission port 44 may be accommodated in the cover body 51. In this case, if a lens is disposed in the hole 54 formed in the light emission support portion 52 and the exit port 44 of the light emission portion 41 is visible through this lens, the light emission portion 41 is connected to the light guide portion 61 and the photosensitive drum 23. It is possible to irradiate light for neutralizing.

  Further, the light emitting unit 41 may not be covered with the light emitting support unit 52 in the front side F, the left and right direction, and the up and down direction of the printer 1. Even in this case, since the portion of the light emitting unit 41 on the fixing unit 7 side is shielded by the shielding wall 53, the heat from the fixing unit 7 is prevented from reaching the light emitting unit 41 compared to the case where there is no shielding wall 53. can do.

  In this case, air flows into or out of the space between the light emitting unit 41 and the shielding wall 53 or the space between the substrate 42 and the shielding wall 53 from, for example, the horizontal direction or the vertical direction of the printer 1. Therefore, the inflow hole 56 and the outflow hole 55 need not be formed.

  In the said embodiment, although the example which was connected so that the 1st light guide part 62 and the 2nd light guide part 63 might orthogonally cross in the light guide part 61 was shown, it is not restricted to this. For example, the receiving portion 66 is disposed on the inner side of both ends 28A, 28B of the frame 28 of the frame 28 of the process cartridge 6 in the rotation axis direction of the photosensitive drum 23, and the first light guide portion 62 and the second light guide portion 63 are disposed. And may be connected to cross each other.

2: casing, 2B: support wall, 2F: rib, 6: process cartridge, 7: fixing unit, 8: EL, 9: fan, 15: guide member, 15D: communication hole, 16: support unit, 17: support Hole: 18: Partition wall, 23: Photosensitive drum, 41: Light emitting part, 42: Substrate, 44: Outlet, 45: Main board, 46: Harness, 51: Cover body, 52: Light emitting support part, 53: Shielding wall , 55: outflow hole, 56: inflow hole, 61: light guide part, 62: first light guide part, 63: second light guide part, 66: receiving part, T: ventilation path

Claims (10)

An electrophotographic image forming apparatus,
A housing,
An image forming unit provided in the housing and having a photoconductor that rotates about a rotation axis;
A fixing unit provided in the housing at a predetermined interval from the photoconductor in a horizontal direction orthogonal to the rotation axis direction of the photoconductor, and having a heating unit;
A light source provided in the housing;
A light guide portion provided in the housing, having a receiving portion for receiving light from the light source, and configured to guide the light received from the receiving portion to the surface of the photoreceptor;
A fan for discharging the air in the housing to the outside;
A shielding wall provided in the housing;
With
The light source is provided between the photosensitive member and the fixing unit in the horizontal direction, and is provided on the inner side of both ends of the image forming unit in the rotation axis direction so as to face the receiving unit.
The shielding wall shields the fixing portion side of the light source and is disposed at a position away from the light source;
The receiving unit is disposed opposite to the light source on the inner side of both ends of the image forming unit in the rotation axis direction,
A ventilation path connected to the fan is formed between the light source and the shielding wall.
Image forming apparatus. The image forming apparatus according to claim 1,
The light source has an exit for emitting light,
Furthermore,
A cover body that accommodates at least a portion of the light source excluding the emission port and has a hole that opens the emission port,
The cover body is configured with the shielding wall as a part of the cover body, and an inflow hole and an outflow hole are formed in a portion excluding the shielding wall of the cover body,
The fan is provided on the side of the cover body where the outflow hole is formed,
A ventilation path connected to the fan is formed between the light source and the shielding wall via the inflow hole and the outflow hole.
Image forming apparatus. The image forming apparatus according to claim 2,
The inflow hole is formed in the lower surface of the cover body,
The outflow hole is formed on the upper surface of the cover body,
The fan is disposed above the cover body,
Image forming apparatus. The image forming apparatus according to claim 3, wherein
The fan is provided on a side surface of the casing on one end side of both ends of the image forming unit in the rotation axis direction.
The light guide is
A first light guide portion that extends in the direction of the rotation axis and is opposed to the photoconductor, and a direction that extends from one end of the first light guide portion in a direction perpendicular to the rotation axis direction and extends A second light guide part, the tip part of which becomes the receiving part,
The light source and the receiving portion are provided on the one end side where the fan is provided on both ends of the image forming portion.
Image forming apparatus. The image forming apparatus according to claim 4,
Furthermore,
A guide member which is provided between the image forming unit and the fixing unit in the housing and guides a sheet from the image forming unit side to the fixing unit side;
With
The guide member is provided with a plurality of communication holes connected to the outside of the housing,
The cover body is provided on the guide member so that one communication hole and the inflow hole among the plurality of communication holes are connected.
Image forming apparatus. The image forming apparatus according to claim 5, wherein
The second light guide portion extends obliquely downward from the one end portion of the first light guide portion, which is a direction orthogonal to the rotation axis direction,
The light source is disposed opposite to the receiving portion, which is the end portion of the second light guide portion extending obliquely downward, and outside the sheet conveyance path on the guide member.
Image forming apparatus. The image forming apparatus according to claim 6,
Furthermore,
A partition wall having a lower end positioned above the outflow hole and having an upper end positioned at a position up to the fan, and extending from both ends of the image forming unit in the rotation axis direction to the end of the image forming unit. A partition wall extending to the upper end,
An image forming apparatus. An image forming apparatus according to any one of claims 4 to 7,
The image forming unit is a process cartridge that can be attached to and detached from the housing,
The process cartridge is provided with the light guide.
Image forming apparatus. An image forming apparatus according to any one of claims 4 to 8,
The opening area of the outflow hole is smaller than the opening area of the inflow hole,
Image forming apparatus. An image forming apparatus according to any one of claims 4 to 9,
Furthermore,
A substrate connected to the light source;
A transmission board for transmitting electrical signals to the board;
With
The substrate is provided on the fixing unit side with respect to the light source,
A harness connecting the substrate and the transmission substrate is disposed via the inflow hole,
Image forming apparatus.

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