JP2018097238A - Image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming apparatus that can improve the degree of freedom in design of an image forming apparatus body.SOLUTION: An image forming apparatus comprises: photoreceptor drums 51; a drum support member that supports the photoreceptor drums 51; and exposure heads 40 that include a plurality of light emitting parts that are arranged in a rotation axis direction of the photoreceptor drum 51, optical members that each form light from the light emitting parts into an image on a surface of the photoreceptor drum 51 and head frames 100, 200 that each support the light emitting parts and optical member, and that each can be moved between an exposure position to expose the photoreceptor drum 51 and a retracted position separated farther from the photoreceptor drum 51 than the exposure position. A head support member includes reference parts 700 that, upon contact with the head frame 200 when the exposure head 40 is at the exposure position, determine the position in a fore-and-aft direction of the exposure head 40. The head frame 200 includes a pressing part 600 that presses the head frame 200 toward one of the reference parts 700.SELECTED DRAWING: Figure 4

Description

  The present invention relates to an image forming apparatus including an exposure head for exposing a photosensitive drum.

  As an image forming apparatus provided with an exposure head, for example, in Patent Document 1, both left and right ends of an exposure head are biased forward by left and right arms provided on a main body frame. There is disclosed a structure in which the portion abuts against the left and right abutting portions of the main body frame, whereby the position of the exposure head in the front-rear direction is determined.

JP 2009-157142 A

  By the way, in the conventional configuration, an arm that urges the exposure head is rotatably provided on the main body frame after the exposure head. For this reason, it is necessary to arrange them so that the rotating arm and other members provided on the main body frame do not interfere with each other, and the design flexibility of the image forming apparatus main body may be restricted.

  SUMMARY An advantage of some aspects of the invention is that it provides an image forming apparatus capable of improving the degree of freedom in designing an image forming apparatus main body.

In order to achieve the above-described object, an image forming apparatus of the present invention includes a photosensitive drum, a drum support member that supports the photosensitive drum, and an exposure head.
The exposure head includes a plurality of light emitting units arranged in the rotation axis direction of the photosensitive drum, an optical member that forms an image of light from the light emitting unit on the surface of the photosensitive drum, a head frame that supports the light emitting unit and the optical member, And is movable between an exposure position for exposing the photosensitive drum and a retracted position farther from the photosensitive drum than the exposure position.
The drum support member has a reference portion that determines the position of the exposure head in the sub-scanning direction orthogonal to both the optical axis direction and the rotation axis direction by contacting the head frame when the exposure head is at the exposure position.
The head frame has a pressing portion that presses the head frame toward the reference portion.

  According to such a configuration, it is not necessary to provide the pressing portion in the image forming apparatus main body, so that the degree of design freedom of the image forming apparatus main body can be improved.

  According to the present invention, the degree of freedom in designing the image forming apparatus main body can be improved.

1 is a diagram illustrating a schematic configuration of a color printer according to an embodiment of the present invention. It is a figure which shows the color printer of the state which opened the cover. It is a figure which shows the exposure head and drum unit which are located in an exposure position. It is XX sectional drawing of FIG. It is the figure seen from the Y direction of FIG. It is explanatory drawing (a), (b) of operation | movement when moving an exposure head from an evacuation position to an exposure position. It is explanatory drawing (a), (b) of operation | movement when moving an exposure head from an evacuation position to an exposure position. It is explanatory drawing (a), (b) of operation | movement when moving an exposure head from an evacuation position to an exposure position.

  Next, an embodiment of the present invention will be described in detail with reference to the drawings as appropriate. In the following description, first, a schematic configuration of the color printer 1 as an example of an image forming apparatus will be briefly described, and then a configuration of a characteristic part of the present invention will be described in detail.

  In the following description, the directions are defined as “front” on the left side, “rear” on the right side, “left” on the back side, and “right” on the near side in FIG. Further, the upper side in FIG. 1 is “upper” and the lower side is “lower”.

  As shown in FIG. 1, the color printer 1 mainly includes a main body housing 10, a cover 11, and a paper feeding unit 20 and an image forming unit 30 provided in the main body housing 10.

  The cover 11 is disposed in the vertical direction on the opposite side of the exposure head 40 from the side on which the photosensitive drum 51 is disposed, specifically, above the main body housing 10. The cover 11 is supported so as to be rotatable about the rotation shaft 11 </ b> A with respect to the main body housing 10, and opens and closes an opening 10 </ b> A formed in the upper portion of the main body housing 10. Specifically, the cover 11 rotates about an axis parallel to the left-right direction, which is provided at a position apart from the photosensitive drum 51 in the back-and-forth direction. Thereby, the cover 11 can be rotated between a closed position (the position in FIG. 1) for closing the opening 10A and an open position (the position in FIG. 2) for opening the opening 10A.

  The paper feed unit 20 is provided at a lower portion in the main body housing 10, and mainly includes a paper feed tray 21 that stores the paper P and a paper supply mechanism 22 that supplies the paper P from the paper feed tray 21 to the image forming unit 30. In preparation. The paper P in the paper feed tray 21 is separated one by one by the paper supply mechanism 22 and supplied to the image forming unit 30.

  The image forming unit 30 mainly includes four exposure heads 40, four process cartridges PC, a transfer unit 70, and a fixing unit 80.

  The exposure head 40 has a plurality of LEDs at its tip and is supported by a cover 11 (specifically, a holder 12 described later) so as to be suspended from the cover 11. Opposed above the drum 51 is disposed. Specifically, the exposure head 40 opens and closes the cover 11 to expose the photosensitive drum 51 (position in FIG. 1) and a retracted position (in FIG. 2) farther from the photosensitive drum 51 than the exposure position. Position). The exposure head 40 exposes the surface of the photosensitive drum 51 by blinking a plurality of LEDs based on image data. The structure of the exposure head 40 will be described in detail later.

  Each process cartridge PC is arranged in parallel along the front-rear direction between the cover 11 and the paper feed tray 21. Each process cartridge PC (specifically, a drum frame 55 described later) can be attached to and detached from the main body housing 10 through the opening 10 </ b> A when the cover 11 is opened (see FIG. 2). The process cartridge PC includes a drum unit 50 and a developing cartridge 60 that can be attached to and detached from the drum unit 50.

  The drum unit 50 includes a cylindrical photosensitive drum 51, a charger 52 that charges the photosensitive drum 51, a pressing spring 53 that biases the developing cartridge 60 toward the photosensitive drum 51, a cleaning roller 54, and a photosensitive roller. And a drum frame 55 that supports the body drum 51 and the like.

  The cleaning roller 54 is a roller that removes foreign matters such as toner remaining on the photosensitive drum 51. The cleaning roller 54 is rotatable in contact with the photosensitive drum 51.

  The developing cartridge 60 mainly includes a toner containing portion 61 that contains toner, and a developing roller 62 that supplies the toner in the toner containing portion 61 to the photosensitive drum 51.

  The transfer unit 70 is provided between the paper feed tray 21 and the process cartridge PC. The transfer unit 70 mainly includes a driving roller 71, a driven roller 72, an endless conveyance belt 73 stretched between the driving roller 71 and the driven roller 72, and four transfer rollers 74. The outer surface of the conveyance belt 73 is in contact with each photosensitive drum 51, and the transfer roller 74 is disposed inside the conveyance belt 73 so as to sandwich the conveyance belt 73 with each photosensitive drum 51.

  The fixing unit 80 is provided behind the process cartridge PC and the transfer unit 70 and mainly includes a heating roller 81 and a pressure roller 82 that is disposed to face the heating roller 81 and presses the heating roller 81.

  In such an image forming unit 30, the surface of the photosensitive drum 51 is uniformly charged by the charger 52 and then exposed by the exposure head 40, so that a static image based on the image data is formed on the photosensitive drum 51. An electrostatic latent image is formed. Then, toner is supplied from the developing roller 62 to the photosensitive drum 51, whereby the electrostatic latent image is visualized and a toner image is formed on the photosensitive drum 51.

  The toner images formed on the respective photoconductive drums 51 are sequentially superimposed and transferred onto the paper P transported on the transport belt 73 by the transfer roller 74. The paper P onto which the toner image has been transferred is conveyed between the heating roller 81 and the pressure roller 82, whereby the toner image is thermally fixed. Thereafter, the paper P is discharged from the main body housing 10 to the outside by the transport roller 91 and placed on a paper discharge tray 11 </ b> B formed on the upper surface of the cover 11.

Next, the exposure head 40 and the structure around the exposure head 40 will be described in detail.
As shown in FIG. 3, in the present embodiment, the rotation axis X1 of the photosensitive drum 51 extends in the left-right direction. In the following description, the direction in which the rotation axis X1 extends, that is, the left-right direction is also simply referred to as “rotation axis direction”.

  The photosensitive drum 51 includes a cylindrical element tube 51A and two fitting members 400 that are fitted to the inner peripheral surface of the element tube 51A. The elementary tube 51A is made of a conductive material such as metal. A photosensitive layer (not shown) is formed on the outer peripheral surface of the base tube 51A. In the following description, the outer peripheral surface of the raw tube 51A is also referred to as “surface”. The photosensitive layer is formed outside the exposure range ER of the exposure head 40 in the rotation axis direction. The raw tube 51A is electrically connected to the metal member of the main body housing 10 and connected to the ground potential.

  The fitting member 400 is provided on one end side and the other end side in the rotation axis direction of the raw tube 51A. The fitting member 400 is made of resin. The fitting member 400 can be rotated together with the raw pipe 51A by fitting into the inner peripheral surface of the raw pipe 51A. The fitting member 400 integrally includes a fitting portion 410 located on the inner side in the rotational axis direction than the end surface of the raw tube 51A and an exposed portion 420 located on the outer side in the rotational axis direction from the end surface of the raw tube 51A. doing.

  Each end of the photosensitive drum 51 in the direction of the rotation axis is rotatably supported by a rotation support member 500. Each rotation support member 500 is supported by the drum frame 55. Further, the drum frame 55 attached to the main body housing 10 is supported by the main body housing 10.

  In the present embodiment, the “drum support member” includes the rotation support member 500, the drum frame 55 that rotatably supports the photosensitive drum 51 via the rotation support member 500, and the main body housing 10 that supports the drum frame 55. Is configured. That is, in this embodiment, the drum support member that supports the photosensitive drum 51 includes the rotation support member 500, the drum frame 55, and the main body housing 10.

  The rotation support member 500 is a member that rotatably supports the outer peripheral surface of the exposed portion 420 of the fitting member 400. The rotation support member 500 is configured as a sliding bearing made of resin. The rotation support member 500 mainly includes a cylindrical bearing portion 510 that rotatably supports the fitting member 400 and an extending portion 530 that extends from the bearing portion 510 toward the exposure head 40.

  The extending portion 530 has a contact surface 531 with which the exposure head 40 contacts at the tip. The contact surface 531 defines the distance in the optical axis direction from the lens array 102 to the surface of the photosensitive drum 51 by contacting the interval adjusting member 300 of the exposure head 40.

  The exposure head 40 includes a first frame 100 and a second frame 200, an interval adjustment member 300 disposed between the second frame 200 and the drum unit 50 (specifically, the rotation support member 500), and an example of a pressing unit. 1st press part 600 is provided.

  The first frame 100 and the second frame 200 constitute a head frame that is a frame of the exposure head 40. In other words, in the present embodiment, the head frame is configured to include the first frame 100 and the second frame 200. The first frame 100 and the second frame 200 are made of resin.

  The first frame 100 integrally includes a substantially rectangular parallelepiped base portion 110 that is long in the left-right direction, and two extending portions 120 that extend outward in the left-right direction from the respective end surfaces of the base portion 110 in the left-right direction. . The base part 110 is made of resin and is open in the up-down direction.

  A plurality of LED arrays 101 are provided in the base portion 110. The plurality of LED arrays 101 are arranged in the rotation axis direction. A lens array 102 as an example of an optical member that forms an image of light from the LED array 101 on the surface of the photosensitive drum 51 is provided in the opening below the base portion 110. That is, the base part 110 of the first frame 100 supports the plurality of LED arrays 101 and the lens array 102.

The LED array 101 is a semiconductor element having a plurality of light emitting portions (LEDs) arranged in the rotation axis direction, and the surface of the photosensitive drum 51 is scanned and exposed when each light emitting portion blinks.
The lower surface of the lens array 102 is an emission surface that emits light, and faces the rotation axis X1 side.

  In the following description, a direction in which the photosensitive drum 51 is scanned in the rotation axis direction by the plurality of LED arrays 101 arranged in the rotation axis direction is referred to as a main scanning direction. Further, the optical axis direction of the light emitted from the LED array 101 is simply referred to as “optical axis direction”. Further, a direction orthogonal to both the optical axis direction and the main scanning direction is referred to as a sub-scanning direction. In the present embodiment, the sub-scanning direction substantially coincides with the front-rear direction, and is also referred to as the front-rear direction as appropriate. In the present embodiment, the optical axis direction substantially coincides with the up-down direction, and hence is also referred to as the up-down direction as appropriate.

  The second frame 200 is a frame that supports the first frame 100, and is supported in a state of being suspended by a resin holder 12 that is rotatably supported by the cover 11. The second frame 200 integrally includes a substantially rectangular base portion 210 that is long in the left-right direction, two projecting portions 220, a first edge portion 230, a second edge portion 240, and a third edge portion 250. ing.

  The base part 210 has a first recess 211 and a hole 213. Two holes 213 are provided at intervals in the left-right direction. Each hole 213 is disposed symmetrically with respect to the center of the base portion 210 in the left-right direction. Each hole 213 penetrates the base portion 210 in the front-rear direction.

  The holder 12 has a hook 12 </ b> A for suspending the base portion 210 at a position corresponding to each hole 213. The tip of each hook 12A protrudes inward in the front-rear direction and engages with each hole 213. The holder 12 holds the base portion 210 with play in the front-rear direction and the up-down direction. In other words, the exposure head 40 is supported so as to be movable in the front-rear direction and the vertical direction with respect to the cover 11 via the holder 12.

  The first recess 211 is a recess that opens toward the holder 12 side. One first recess 211 is formed on the outer side in the left-right direction with respect to the two left and right holes 213. A compression coil spring SP that is an urging member is provided between the bottom surface of the first recess 211 and the holder 12. The compression coil spring SP biases the exposure head 40 toward the photosensitive drum 51.

  Each protruding portion 220 is a portion that supports both ends of the first frame 100 in the rotation axis direction, and protrudes from the lower surface of the base portion 210 to the photosensitive drum 51 side. Specifically, each protrusion 220 protrudes in the optical axis direction from the lens array 102. The first frame 100 is supported by the second frame 200 by attaching the extended portion 120 to the protruding portion 220.

  The first edge portion 230 and the third edge portion 250 are arranged on one side of the base portion 210 in the rotation axis direction, specifically, on the right end portion. As shown in FIG. 4, the first edge portion 230 is disposed at one side of the second frame 200 in the optical axis direction, specifically, at an upper position. Further, the first edge portion 230 is disposed at a position near the center of the second frame 200 in the front-rear direction. The first edge portion 230 has a substantially flat first head-side contact surface 231 that contacts a first reference portion 710 described later on one side in the sub-scanning direction, specifically, on the rear side. .

  The third edge 250 is arranged away from the first edge 230 in the optical axis direction. Specifically, the third edge 250 is disposed at the other side in the optical axis direction of the second frame 200, specifically, at a lower position. More specifically, the third edge 250 is located downstream of the first edge 230, specifically, on the lower side in the direction of movement from the retracted position of the exposure head 40 to the exposure position (from the top to the bottom). Is arranged.

  The third edge 250 is disposed at a position shifted in the front-rear direction with respect to the first edge 230. Specifically, the third edge 250 is disposed at a position shifted from the center of the second frame 200 in the front-rear direction to the other side in the sub-scanning direction, specifically, the front side. A lower end portion 252 that is a lower end portion of the third edge portion 250 has a tapered shape in which the width in the front-rear direction becomes narrower toward the photosensitive drum 51. FIG. 4 is a cross-sectional view taken along the line XX of FIG. 3, but shows a photosensitive drum 51 as a reference.

  The third edge 250 has a substantially flat third head-side contact surface 251 that contacts a third reference portion 730, which will be described later, on the rear side. The third head-side contact surface 251 is arranged at a position different from the first head-side contact surface 231 in the front-rear direction. Specifically, the third head-side contact surface 251 is disposed at a position shifted forward from the first head-side contact surface 231.

  As shown in FIG. 3, the second edge portion 240 is disposed on the other side of the base portion 210 in the rotation axis direction, specifically, on the left end portion. As shown in FIG. 5, the second edge portion 240 is located on the lower side of the second frame 200 and on the rear side.

  The lower end portion 242 that is the lower end portion of the second edge portion 240 has a tapered shape that inclines so that the front surface approaches the rear side as it goes toward the photosensitive drum 51. The second edge 240 has a substantially flat second head-side contact surface 241 that contacts a second reference portion 720 described later on the front side.

  As shown in FIG. 3, the interval adjusting member 300 is an example of an abutting portion. It is a member for defining the distance.

  The interval adjusting member 300 is made of resin. The interval adjusting member 300 integrally includes a main body portion 310A and a boss 310B that protrudes upward from the main body portion 310A. The width of the main body portion 310A in the front-rear direction becomes narrower toward the photosensitive drum 51 (see FIG. 4). The interval adjusting member 300 is attached to the second frame 200 by inserting the bosses 310 </ b> B into both ends of the base portion 210 in the rotation axis direction from below.

  As shown in FIG. 4, the first pressing unit 600 presses the head frame (specifically, the second frame 200) of the exposure head 40 toward the first reference unit 710 and the third reference unit 730 described later. And is provided on the second frame 200. The first pressing part 600 includes a contact member 610 and a spring member 620.

  The contact member 610 is made of a highly slidable resin such as polyacetal (POM). The contact member 610 is a member that contacts the head guide 800 provided in the main body housing 10 (drum support member) when the exposure head 40 is at the exposure position. It has the part 612 integrally.

  The contact member main body 611 is a portion that contacts the head guide 800. A surface of the contact member main body 611 that contacts the head guide 800 is a substantially arc-shaped convex curved surface when viewed from the direction of the rotation axis. The extending portion 612 extends rearward from both ends of the contact member main body 611 in the vertical direction. A claw 613 that protrudes outward in the vertical direction is formed at the tip of the extending portion 612.

  The contact member 610 is supported by the second frame 200 so as to be movable in the front-rear direction by being disposed on the guide portion 260 provided on the second frame 200. The guide part 260 has upper and lower guide walls 261 (not shown) extending in the front-rear direction, and a bottom wall 262.

  The guide wall 261 is a wall that guides the movement of the contact member 610 in the front-rear direction. When the contact member 610 is pushed into the guide portion 260 from the front side, the contact portion 610 enters the guide portion 260 while the extension portion 612 is elastically deformed by the inclination of the claw 613. Then, after the claw 613 passes through the guide wall 261, the shape of the extending part 612 is restored, so that the contact member 610 is disposed on the guide part 260 and the claw 613 is hooked on the guide wall 261. The contact member 610 is prevented from falling off.

  The spring member 620 is a member that presses the contact member 610 toward the head guide 800 when the exposure head 40 is at the exposure position. The spring member 620 is a compression coil spring, for example, and is disposed between the contact member 610 and the bottom wall 262 of the guide portion 260.

  As shown in FIG. 3, the first pressing portion 600 is disposed outside the exposure range ER of the exposure head 40 in the rotation axis direction. Further, the first pressing portion 600 is disposed outside the interval adjusting member 300 in the rotation axis direction.

  As shown in FIGS. 4 and 5, the main body housing 10 is provided with a reference portion 700, a head guide 800, and a second pressing portion 900. The reference portion 700 is a portion for determining the position of the exposure head 40 in the front-rear direction by the second frame 200 contacting when the exposure head 40 is at the exposure position. The reference unit 700 includes a first reference unit 710, a second reference unit 720, and a third reference unit 730.

  As shown in FIG. 3, the first reference portion 710 and the third reference portion 730 are arranged to face the right end portion of the exposure head 40, and the second reference portion 720 is located at the left end portion of the exposure head 40. It arrange | positions so that it may oppose. In other words, the first reference portion 710 and the third reference portion 730 are arranged on the same side in the left-right direction. Further, the second reference portion 720 is disposed on the opposite side of the first reference portion 710 and the third reference portion 730 in the left-right direction.

  Further, as shown in FIG. 4, the first reference portion 710 and the third reference portion 730 are arranged on the rear side with respect to the first edge portion 230 and the third edge portion 250 of the second frame 200, As shown in FIG. 5, the second reference portion 720 is disposed on the front side with respect to the second edge portion 240 of the second frame 200. In other words, the second reference portion 720 is opposite to the side where the first reference portion 710 and the third reference portion 730 are disposed with respect to the edge portions 230 and 250 with respect to the second edge portion 240 in the front-rear direction. Has been placed.

  As shown in FIG. 4, the first reference portion 710 and the third reference portion 730 are provided so as to protrude from the positioning portion 701 provided in the main body housing 10 toward the front side. The positioning portion 701 is a portion where the first edge portion 230, the guide portion 260, and the third edge portion 250 face each other when the exposure head 40 is at the exposure position.

  The first reference portion 710 and the third reference portion 730 are arranged apart from each other in the vertical direction. Specifically, the first reference portion 710 is disposed on the upper side, and the third reference portion 730 is disposed on the lower side. More specifically, the third reference unit 730 is disposed on the downstream side, specifically, on the lower side of the first reference unit 710 in the moving direction from the retracted position of the exposure head 40 to the exposure position.

  The first reference portion 710 has a first main body side contact surface 711 with which the first head side contact surface 231 of the first edge 230 provided on the second frame 200 contacts, and the third reference portion. 730 has a third main body side contact surface 731 with which the third head side contact surface 251 of the third edge 250 contacts. The first main body side contact surface 711 and the third main body side contact surface 731 are substantially curved surfaces having a substantially arc shape when viewed from the rotation axis direction.

  The head guide 800 is a member for guiding the exposure head 40 that moves from the retracted position toward the exposure position. The head guide 800 is disposed to face the positioning unit 701 on the front side of the positioning unit 701. When the exposure head 40 is at the exposure position, the exposure head 40 is disposed between the positioning portion 701 and the head guide 800.

  The head guide 800 includes a first guide surface 810, a second guide surface 820 that guides the exposure head 40 toward the first guide surface 810, and a third guide that guides the exposure head 40 toward the second guide surface 820. Surface 830. The first guide surface 810, the second guide surface 820, and the third guide surface 830 are inclined surfaces that are positioned on the front side toward the upper side when viewed from the rotational axis direction. The first guide surface 810, the second guide surface 820, and the third guide surface 830 have an inclination angle with respect to the vertical direction that increases in this order.

  As shown in FIG. 5, the second reference portion 720 has a second body-side contact surface 721 that contacts the second head-side contact surface 241 of the second edge 240 provided on the second frame 200. ing. Similar to the first main body side contact surface 711 and the third main body side contact surface 731, the second main body side contact surface 721 is a substantially arc-shaped convex curved surface when viewed from the rotational axis direction.

  The second reference portion 720 is disposed at a position overlapping the third reference portion 730 when viewed from the rotation axis direction. In other words, the second reference portion 720 is disposed at substantially the same position as the third reference portion 730 in the moving direction from the retracted position of the exposure head 40 to the exposure position. On the other hand, the first reference portion 710 is disposed upstream of the second reference portion 720 in the moving direction from the retracted position of the exposure head 40 to the exposure position, specifically, on the upper side.

  The second pressing portion 900 is a member for pressing the head frame (specifically, the second frame 200) of the exposure head 40 toward the second reference portion 720. The second pressing portion 900 has a rotating arm 910 and a torsion spring 920.

  The rotating arm 910 is rotatably supported by a rotating shaft 13 provided in the main body housing 10. A protruding portion 911 that protrudes toward the front side is provided at the upper end portion of the rotating arm 910. The tip of the protrusion 911 has an inclined surface that is positioned on the rear side as it goes upward. The torsion spring 920 is a member that applies a biasing force to the rotating arm 910 in the clockwise direction in FIG.

  When the exposure head 40 is at the exposure position, the second pressing portion 900 presses the second edge 240 toward the second reference portion 720 by the protrusion 911 of the rotating arm 910. When the exposure head 40 is not at the exposure position, the protrusion 911 is restricted from rotating by contacting the second reference portion 720 (see FIG. 6).

  In the present embodiment, the second pressing portion 900 presses the second frame 200 toward the second reference portion 720, and the first pressing portion 600 presses the second frame 200 to the first reference portion 710 and the third reference portion. The direction of pressing toward 730 is different. Specifically, the second pressing portion 900 presses the second edge portion 240 of the second frame 200 toward the front side where the second reference portion 720 is disposed.

  On the other hand, as shown in FIG. 4, the first pressing portion 600 is a reaction force caused by the spring member 620 pressing the contact member 610 toward the head guide 800, and the first edge portion 230 of the second frame 200 and The third edge portion 250 is pressed toward the rear side where the first reference portion 710 and the third reference portion 730 are disposed.

Next, an operation for moving the exposure head 40 from the retracted position (position in FIG. 2) to the exposure position (position in FIG. 1) will be described.
When the cover 11 is closed from the open position in FIG. 2 toward the closed position in FIG. 1, the exposure head 40 moves downward as shown in FIG. 6. First, the third edge 250. Is in contact with the third guide surface 830 of the head guide 800 as indicated by a two-dot chain line.

  Thereafter, in the exposure head 40, the third edge 250 is positioned with the first guide surface 810 while the lower end 252 of the third edge 250 slides on the third guide surface 830 and the second guide surface 820 of the head guide 800. It moves toward the part 701. Then, as shown in FIG. 7, the lower end 252 of the third edge 250 is separated from the second guide surface 820, and the third edge 250 enters between the first guide surface 810 and the positioning portion 701. Further, the contact member 610 of the first pressing part 600 contacts the third guide surface 830.

  Then, as shown in FIG. 8, when the exposure head 40 moves further downward, the first pressing portion 600 enters between the positioning portion 701 and the head guide 800, and the contact member 610 moves the spring member 620. The guide part 260 is entered while being compressed. At this time, the abutting member 610 presses the first guide surface 810 by the urging force of the spring member 620, whereby the second frame 200 is urged rearward by the reaction force, and the third edge 250 is The head side contact surface 251 contacts the third main body side contact surface 731 of the third reference portion 730.

  In the operation so far, the second edge portion 240 is in a free state that has not yet entered between the second reference portion 720 and the protruding portion 911 of the second pressing portion 900. Thereafter, as shown in FIG. 4, when the exposure head 40 moves further downward, the first head-side contact surface 231 of the first edge 230 is pressed against the first reference portion 710 by the pressing force of the first pressing portion 600. It abuts on the first main body side abutment surface 711.

  At this time, specifically, when the exposure head 40 moves from the position shown in FIG. 8B to the position shown in FIG. 5, the second edge 240 is inclined at the lower end 242 of the protrusion 911. The surface is pushed and the rotating arm 910 is rotated counterclockwise in FIG. 5 while resisting the biasing force of the torsion spring 920, and enters between the protruding portion 911 and the second reference portion 720. As a result, the second head-side contact surface 241 of the second edge 240 contacts the second main body-side contact surface 721 of the second reference portion 720 by the pressing force of the second pressing portion 900.

  As shown in FIG. 3, the exposure head 40 reaches the exposure position when the interval adjusting member 300 abuts against the abutting surface 531 of the rotation support member 500, and reaches from the lens array 102 to the photosensitive drum 51. The distance in the optical axis direction is defined.

According to the above, the following effects can be obtained in the present embodiment.
Since the first reference part 710 is arranged on the rear side with respect to the second frame 200 and the second reference part 720 is arranged on the front side with respect to the second frame 200, the degree of freedom of arrangement of the reference part 700 is improved. Can be made. Thereby, the design freedom of the structure around the exposure head 40 can be improved. For example, in a configuration in which the process cartridge PC is detachable, it is easy to dispose the second pressing portion 900 and the like at a position that does not interfere with the guide while providing a guide for detaching the cartridge in the main body housing 10.

  In addition, since the first main body side contact surface 711, the second main body side contact surface 721, and the like are convex curved surfaces when viewed from the rotation axis direction, the second frame 200 and the reference portion 700 are contacted in a linear or dotted manner. Can be made. As a result, the second frame 200 can be brought into contact with a desired position of the reference portion 700, so that the position of the exposure head 40 in the front-rear direction can be accurately determined. In addition, since the sliding resistance between the second frame 200 and the reference portion 700 can be reduced, the exposure head 40 can be smoothly moved between the exposure position and the retracted position.

  Further, since the three reference portions 700 (710, 720, 730) are provided, the second frame 200 and the reference portion 700 can be brought into contact with each other at three locations. Thereby, the position of the exposure head 40 in the front-rear direction can be determined with high accuracy.

  Further, since the first reference unit 710 is disposed upstream of the second reference unit 720 in the movement direction from the retracted position of the exposure head 40 to the exposure position, the first reference unit 710 is in the state where the exposure head 40 is in the exposure position. The first pressing portion 600 that presses the two frames 200 toward the first reference portion 710 is located upstream of the second pressing portion 900 that presses the second frame 200 toward the second reference portion 720 in the movement direction. It becomes possible to arrange.

  Therefore, when moving the exposure head 40 from the retracted position to the exposure position, first, only the contact member 610 of the first pressing portion 600 is operated against the biasing force of the spring member 620, and then the second pressing portion. The 900 rotating arms 910 can be operated against the biasing force of the torsion spring 920. That is, the pressing parts 600 and 900 can be operated one by one. Thereby, compared with the case where both pressing parts are operated simultaneously, the resistance when the exposure head 40 is moved becomes smaller, so that the exposure head 40 can be moved toward the exposure position with a small force.

  In addition, since the cover 11 that supports the exposure head 40 is rotatable about the rotation axis 11A, the exposure head 40 is moved to the exposure position along the rotation trajectory of the cover 11 by rotating the cover 11. It can be moved between the retracted positions.

  Further, since the exposure head 40 is supported so as to be movable in the front-rear direction, the second frame 200 is brought into contact with the reference portion 700 when the exposure head 40 is moved from the retracted position to the exposure position. 200 can be made to follow the reference unit 700. Thereby, the position of the exposure head 40 in the front-rear direction can be determined with high accuracy. Further, since the exposure head 40 is supported so as to be movable in the vertical direction and is urged toward the photosensitive drum 51 by the compression coil spring SP, the vertical position of the exposure head 40 can be accurately defined. . Thereby, the photosensitive drum 51 can be satisfactorily exposed by the exposure head 40.

  Further, the position where the third edge 250 arranged on the downstream side of the first edge 230 in the moving direction from the retracted position of the exposure head 40 to the exposure position is shifted to the front side of the upstream first edge 230. Therefore, when the exposure head 40 moves from the retracted position to the exposure position, the third edge portion 250 that approaches the first reference portion 710 first is prevented from interfering with the first reference portion 710. be able to.

  Further, since the second frame 200 of the exposure head 40 has the first pressing portion 600, it is not necessary to provide the main body housing 10 with a pressing portion that presses the second frame 200 toward the reference portions 710 and 730. Thereby, the design freedom of the color printer 1 can be improved. For example, when the same configuration as the second pressing unit 900 is provided on one side in the rotation axis direction of the exposure head 40 as a pressing unit that presses the second frame 200 toward the reference units 710 and 730, the exposure head 40. Although it is necessary to consider arrangement and shape so as not to interfere with other members around the area, according to the present embodiment, such a restriction can be eliminated.

  In addition, the first pressing portion 600 is provided not on the first frame 100 that supports optical components such as the LED array 101 and the lens array 102 but on the second frame 200 provided separately from the first frame 100. The force by which the first pressing portion 600 presses the second frame 200 toward the reference portions 710 and 730 acts on the second frame 200 but is less likely to act on the first frame 100. Thereby, since the deformation | transformation of the 1st flame | frame 100, etc. can be suppressed, the photosensitive drum 51 can be favorably exposed by the LED array 101 or the lens array 102. FIG.

  Moreover, since the contact member 610 that contacts the reference portions 710 and 730 of the first pressing portion 600 is made of resin, the sliding property between the first pressing portion 600 and the reference portions 710 and 730 of the main body housing 10 is improved. Can be increased. Thereby, the exposure head 40 can be smoothly moved between the exposure position and the retracted position.

  In addition, since the second frame 200 includes the guide portion 260 that guides the movement of the contact member 610, the contact member 610 can be stably moved as compared with a configuration that does not include the guide portion. Accordingly, the second frame 200 of the exposure head 40 can be accurately pressed toward the reference portions 710 and 730 by the contact member 610, so that the position of the exposure head 40 in the front-rear direction can be accurately determined. it can.

  Further, since the first pressing part 600 and the second pressing part 900 are arranged outside the exposure range ER of the exposure head 40 in the rotation axis direction, the pressing parts 600 and 900 use the second frame 200 as the reference part 700. It is possible to suppress the pressing force from acting within the exposure range ER of the exposure head 40. Thereby, since it can suppress that the force with which the press parts 600 and 900 press the 2nd frame 200 affects the exposure range ER of the exposure head 40, the photosensitive drum 51 can be favorably exposed by the exposure head 40. it can.

  In addition, this invention is not limited to the said embodiment, It can utilize with various forms so that it may illustrate below. In the following description, the same reference numerals are given to members having substantially the same structure as in the above embodiment, and the description thereof is omitted.

  In the above embodiment, the head side contact surfaces 231, 241, 251 are flat surfaces, and the main body side contact surfaces 711, 721, 731 are curved surfaces, but the present invention is not limited to this, and the head side contact surfaces are It is good also as a curved surface and makes a main body side contact surface into a plane. The curved surface may be a spherical surface. In this case, the reference portion and the head frame of the exposure head can be brought into point contact.

  In the above-described embodiment, the exposure head 40 has the structure including the two frames 100 and 200 as the head frame. However, the present invention is not limited to this, and the exposure head may have a structure including one frame as the head frame. In this case, an optical component such as a light emitting unit, an interval adjusting member, and a first pressing unit may be provided in one frame.

  In the embodiment, the contact member 610 of the first pressing portion 600 is provided to be linearly movable in the front-rear direction. However, the present invention is not limited to this, and for example, the contact member is provided to be rotatable. It may be.

  In the embodiment, the compression coil spring SP is exemplified as the urging member. However, the urging member may be, for example, a plate spring or a torsion spring. The same applies to the spring member of the first pressing portion.

  In the embodiment, the interval adjusting member 300 (contact portion) is in contact with the rotation support member 500. However, the present invention is not limited to this. For example, the contact portion may be in contact with the drum frame. Moreover, it is good also as a structure where a contact part contacts a main body housing | casing. Further, in the above-described embodiment, the contact portion is provided in the exposure head 40 by attaching the interval adjusting member 300 to the second frame 200. However, the contact portion is not limited to this. For example, the contact portion is the head of the exposure head. It may be a part of the frame.

  The material of each component such as the fitting member and the rotation support member is not limited to the above embodiment, and various materials can be selected and used. Further, the rotation support member may be a rolling bearing instead of a sliding bearing.

  In the embodiment, the plurality of light emitting units (LEDs) provided in the LED array 101 are illustrated as the plurality of light emitting units. However, the present invention is not limited to this. For example, the exposure head includes one light emitting member, and a light emitting member. In the case of having a plurality of shutters that block / release light from the light source, one light emitting unit may be composed of one shutter and a part of the light emitting member corresponding to the shutter.

  In the embodiment, the first reference unit 710 is disposed on the upstream side in the moving direction from the retracted position of the exposure head 40 to the exposure position with respect to the second reference unit 720. However, the present invention is not limited to this. The portion may be arranged upstream of the first reference portion in the movement direction of the exposure head.

  In the above-described embodiment, the reference unit 700 is provided in the main body housing 10. However, the present invention is not limited to this. For example, the reference unit may be provided in a drum frame or the like. Further, the reference unit may be provided in a drawer that supports the photosensitive drum and is movable with respect to the main body housing. In other words, the drum support member may have a drawer.

  In the embodiment, the first pressing portion 600 as the pressing portion is provided only at one end portion of the exposure head 40 in the rotation axis direction. However, the present invention is not limited to this. For example, the pressing portion is exposed in the rotation axis direction. It may be provided at both ends of the head. The pressing portions may be provided on both sides of the exposure head in the sub-scanning direction.

  In the above embodiment, the present invention is applied to the color printer 1. However, the present invention is not limited to this, and the present invention may be applied to other image forming apparatuses such as a copying machine and a multifunction machine.

  Moreover, you may implement combining each element demonstrated by above-described embodiment and modification arbitrarily.

DESCRIPTION OF SYMBOLS 1 Color printer 10 Main body housing | casing 40 Exposure head 51 Photoconductor drum 100 1st frame 101 LED array 102 Lens array 200 2nd frame 260 Guide part 300 Space | interval adjustment member 500 Rotation support member 600 1st press part 610 Contact member 620 Spring Member 700 Reference portion 710 First reference portion 711 First main body side contact surface 720 Second reference portion 721 Second main body side contact surface 730 Third reference portion 731 Third main body side contact surface

Claims (8)

A photosensitive drum;
A drum support member for supporting the photosensitive drum;
A plurality of light emitting units arranged in a rotation axis direction of the photosensitive drum; an optical member that forms an image of light from the light emitting unit on a surface of the photosensitive drum; and a head frame that supports the light emitting unit and the optical member. And an exposure head that is movable between an exposure position that exposes the photosensitive drum and a retracted position that is further away from the photosensitive drum than the exposure position, and
When the exposure head is in the exposure position, the drum support member abuts the head frame to position the exposure head in the sub-scanning direction perpendicular to both the optical axis direction and the rotation axis direction. Has a reference part to decide,
The image forming apparatus according to claim 1, wherein the head frame includes a pressing portion that presses the head frame toward the reference portion.   The image forming apparatus according to claim 1, wherein the reference portion has a convex curved surface when the head frame abuts on the rotation axis. The reference portion includes a first reference portion and a third reference portion arranged on one side in the rotation axis direction, and a second reference portion arranged on the other side in the rotation axis direction,
3. The image forming apparatus according to claim 1, wherein the first reference portion and the third reference portion are disposed apart from each other in the optical axis direction. The head frame includes a first frame that supports the light emitting unit and the optical member, and a second frame that supports the first frame.
The image forming apparatus according to claim 1, wherein the pressing portion is provided on the second frame.   The said pressing part has a resin-made contact member which contact | abuts to the said drum support member, and a spring member which presses the said contact member toward the said drum support member. 5. The image forming apparatus according to any one of 4 above.   The image forming apparatus according to claim 5, wherein the head frame includes a guide portion that guides movement of the contact member in the sub-scanning direction.   The image forming apparatus according to claim 1, wherein the pressing portion is disposed outside the exposure range of the exposure head in the rotation axis direction. The exposure head includes a contact portion that contacts the drum support member and defines a distance in the optical axis direction from the optical member to the photosensitive drum,
The image forming apparatus according to claim 1, wherein the pressing portion is disposed outside the contact portion in the rotation axis direction.

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