JP6870308B2 - Image forming device - Google Patents

Description

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

As an image forming apparatus provided with an exposure head, for example, in Patent Document 1, the left and right ends of the exposure head are urged forward by the left and right arms provided on the main body frame, so that the left and right ends of the exposure head are provided. It is disclosed that the portions are in contact with 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-A-2009-157142

By the way, in the conventional configuration, an arm for urging the exposure head is rotatably provided on the main body frame after the exposure head. Therefore, it is necessary to arrange these so that the rotating arm and other members provided on the main body frame do not interfere with each other, which may limit the degree of freedom in designing the main body of the image forming apparatus.

Therefore, an object of the present invention is to provide an image forming apparatus capable of improving the degree of freedom in designing the image forming apparatus main body.

In order to achieve the above object, the image forming apparatus of the present invention includes a photoconductor drum, a drum support member for supporting the photoconductor drum, and an exposure head.
The exposure head includes a plurality of light emitting parts arranged in the direction of the rotation axis of the photoconductor drum, an optical member that forms an image of light from the light emitting part on the surface of the photoconductor drum, and a head frame that supports the light emitting part and the optical member. It is possible to move between the exposure position where the photoconductor drum is exposed and the retracted position which is farther from the photoconductor 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 abutting the head frame when the exposure head is in 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 on the image forming apparatus main body, so that the degree of freedom in designing 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.

It is a figure which shows the schematic structure of the color printer which concerns on one Embodiment of this invention. It is a figure which shows the color printer with the cover open. It is a figure which shows the exposure head and the drum unit located at the exposure position. FIG. 3 is a cross-sectional view taken along the line XX of FIG. It is a figure seen from the Y direction of FIG. It is explanatory drawing (a), (b) of the operation when moving an exposure head from a retracted position to an exposure position. It is explanatory drawing (a), (b) of the operation when moving an exposure head from a retracted position to an exposure position. It is explanatory drawing (a), (b) of the operation when moving an exposure head from a retracted position to an exposure position.

Next, one 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 the image forming apparatus will be briefly described, and then the configuration of the characteristic portion of the present invention will be described in detail.

Further, in the following description, the left side in FIG. 1 is "front", the right side is "rear", the back side is "left", and the front side is "right". Further, the upper side in FIG. 1 is referred to as "upper" and the lower side is referred to as "lower".

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

The cover 11 is arranged in the vertical direction on the side opposite to the side on which the photoconductor drum 51 of the exposure head 40 is arranged, specifically, above the main body housing 10. The cover 11 is rotatably supported with respect to the main body housing 10 about the rotation shaft 11A, and opens and closes the opening 10A formed in the upper part 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 separated from the photoconductor drum 51 in the front-rear direction. As a result, the cover 11 can rotate between the closing position for closing the opening 10A (the position shown in FIG. 1) and the opening position for opening the opening 10A (the position shown in FIG. 2).

The paper feed unit 20 is provided in the lower part of the main body housing 10, and mainly includes a paper feed tray 21 for accommodating the paper P and a paper supply mechanism 22 for supplying the paper P from the paper feed tray 21 to the image forming unit 30. Be prepared for. 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 is mainly composed of four exposure heads 40, four process cartridge PCs, 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 the cover 11 (more specifically, a holder 12 described later) so as to be suspended from the cover 11. The exposure head 40 has a photoconductor in a closed state. It is arranged so as to face the upper side of the drum 51. Specifically, the exposure head 40 has an exposure position (position in FIG. 1) for exposing the photoconductor drum 51 by opening and closing the cover 11 and a retracted position (FIG. 2) that is farther from the exposure position than the exposure position. It is possible to move between the position). The exposure head 40 exposes the surface of the photoconductor drum 51 by blinking a plurality of LEDs based on the image data. The structure of the exposure head 40 will be described in detail later.

Each process cartridge PC is arranged in parallel between the cover 11 and the paper feed tray 21 along the front-rear direction. Each process cartridge PC (specifically, the drum frame 55 described later) can be attached to and detached from the main body housing 10 through the opening 10A in a state where 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 photoconductor drum 51, a charger 52 for charging the photoconductor drum 51, a pressing spring 53 for urging the developing cartridge 60 toward the photoconductor drum 51, a cleaning roller 54, and photosensitivity. It includes a drum frame 55 that supports the body drum 51 and the like.

The cleaning roller 54 is a roller that removes foreign matter such as toner remaining on the photoconductor drum 51. The cleaning roller 54 comes into contact with the photoconductor drum 51 and can rotate.

The developing cartridge 60 mainly includes a toner accommodating portion 61 for accommodating toner and a developing roller 62 for supplying the toner in the toner accommodating portion 61 to the photoconductor 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 drive roller 71, a driven roller 72, an endless transfer belt 73 stretched between the drive roller 71 and the driven roller 72, and four transfer rollers 74. The outer surface of the transport belt 73 is in contact with each photoconductor drum 51, and each transfer roller 74 is arranged inside the transport belt 73 so as to sandwich the transport belt 73 with each photoconductor 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 arranged to face the heating roller 81 and presses the heating roller 81.

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

The toner image formed on each photoconductor drum 51 is sequentially superimposed and transferred on the paper P transported on the transport belt 73 by the transfer roller 74. On the paper P on which the toner image is transferred, the toner image is thermally fixed by being conveyed between the heating roller 81 and the pressure roller 82. After that, the paper P is discharged from the inside of the main body housing 10 to the outside by the transport roller 91, and is placed on the paper discharge tray 11B formed on the upper surface of the cover 11.

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

The photoconductor drum 51 includes a cylindrical base tube 51A and two fitting members 400 that fit on the inner peripheral surface of the base tube 51A. The raw 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 raw tube 51A. In the following description, the outer peripheral surface of the raw pipe 51A is also referred to as a “surface”. The photosensitive layer is formed to the outside of the exposure range ER of the exposure head 40 in the direction of the rotation axis. The raw pipe 51A conducts with the metal member of the main body housing 10 and is connected to the ground potential.

The fitting member 400 is provided on one end side and the other end side of the raw pipe 51A in the direction of the rotation axis, respectively. The fitting member 400 is made of resin. By fitting the fitting member 400 into the inner peripheral surface of the raw pipe 51A, the fitting member 400 can rotate together with the raw pipe 51A. The fitting member 400 integrally includes a fitting portion 410 located inside the end face of the raw pipe 51A in the rotation axis direction and an exposed portion 420 located outside the end face of the raw pipe 51A in the rotation axis direction. doing.

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

In the present embodiment, the "drum support member" is formed by the rotation support member 500, the drum frame 55 that rotatably supports the photoconductor 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 the present embodiment, the drum support member that supports the photoconductor drum 51 includes a rotation support member 500, a drum frame 55, and a 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 slide bearing made of resin. The rotation support member 500 mainly has a cylindrical bearing portion 510 that rotatably supports the fitting member 400, and an extension portion 530 extending from the bearing portion 510 toward the exposure head 40.

The extending portion 530 has a contact surface 531 at the tip thereof with which the exposure head 40 comes into contact. The contact surface 531 abuts on the interval adjusting member 300 of the exposure head 40 to define the distance in the optical axis direction from the lens array 102 to the surface of the photoconductor drum 51.

The exposure head 40 is, as an example, an interval adjusting member 300 arranged between the first frame 100 and the second frame 200, the second frame 200 and the drum unit 50 (specifically, the rotation support member 500), and a pressing portion. It is provided with a first pressing portion 600.

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

The first frame 100 integrally has a substantially rectangular parallelepiped base portion 110 that is long in the left-right direction and two extension portions 120 that extend outward in the left-right direction from each end face of the base portion 110 in the left-right direction. .. The base portion 110 is made of resin and is open in the vertical direction.

A plurality of LED arrays 101 are provided in the base portion 110. The plurality of LED arrays 101 are arranged in the direction of the rotation axis. A lens array 102 is provided in the lower opening of the base portion 110 as an example of an optical member that forms an image of light from the LED array 101 on the surface of the photoconductor drum 51. That is, the base portion 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 parts (LEDs) arranged in the direction of the rotation axis, and the surface of the photoconductor drum 51 is scanned and exposed by blinking each light emitting part.
The lower surface of the lens array 102 is an exit surface that emits light, and faces the rotation axis X1 side.

In the following description, the direction in which the photoconductor 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, since the sub-scanning direction substantially coincides with the front-back direction, it is also appropriately referred to as a front-back direction. Further, in the present embodiment, since the optical axis direction substantially coincides with the vertical direction, it is also appropriately referred to as a vertical direction.

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 portion 210 has a first recess 211 and a hole 213. Two holes 213 are provided at intervals in the left-right direction. The holes 213 are arranged 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 12A for suspending the base portion 210 at a position corresponding to each hole 213. The tip of each hook 12A projects inward in the front-rear direction and engages with each hole 213. The holder 12 holds the base portion 210 in a state of having play in the front-rear direction and the up-down direction. In other words, the exposure head 40 is supported by the holder 12 so as to be movable in the front-rear direction and the up-down direction with respect to the cover 11.

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

Each protruding portion 220 is a portion that supports both ends of the first frame 100 in the direction of the rotation axis, and protrudes from the lower surface of the base portion 210 toward the photoconductor drum 51. Specifically, each protruding portion 220 protrudes from the lens array 102 in the optical axis direction. The first frame 100 is supported by the second frame 200 by attaching the extending 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 arranged at a position on one side of the second frame 200 in the optical axis direction, specifically, on the upper side. Further, the first edge portion 230 is arranged at a position near the center in the front-rear direction of the second frame 200. The first edge portion 230 has a substantially flat first head-side contact surface 231 that abuts on the first reference portion 710, which will be described later, on one side in the sub-scanning direction, specifically, on the rear side. ..

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

Further, the third edge portion 250 is arranged at a position displaced in the front-rear direction with respect to the first edge portion 230. Specifically, the third edge portion 250 is arranged at a position shifted to the other side in the sub-scanning direction, specifically, the front side from the center in the front-rear direction of the second frame 200. The lower end portion 252, which is the 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 photoconductor drum 51. Note that FIG. 4 is a cross-sectional view taken along the line XX of FIG. 3, but the photoconductor drum 51 is shown as a reference.

The third edge portion 250 has a substantially flat third head-side contact surface 251 that abuts on the 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 that of the first head-side contact surface 231 in the front-rear direction. Specifically, the third head-side contact surface 251 is arranged at a position shifted forward with respect to the first head-side contact surface 231.

As shown in FIG. 3, the second edge portion 240 is arranged on the other side of the base portion 210 in the rotation axis direction, specifically, 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 is arranged on the rear side.

The lower end portion 242, which is the lower end portion of the second edge portion 240, has a tapered shape in which the front surface is inclined so as to approach the rear side toward the photoconductor drum 51. The second edge portion 240 has a substantially flat second head-side contact surface 241 that abuts on the second reference portion 720, which will be described later, on the front side.

As shown in FIG. 3, the interval adjusting member 300 is an example of the contact portion, and by contacting the contact surface 531 of the rotation support member 500, the distance adjusting member 300 is in the optical axis direction from the lens array 102 to the photoconductor drum 51. It is a member for defining the distance.

The interval adjusting member 300 is made of resin. The interval adjusting member 300 integrally has a main body portion 310A and a boss 310B protruding upward from the main body portion 310A. The width of the main body 310A in the front-rear direction becomes narrower toward the photoconductor drum 51 (see FIG. 4). The interval adjusting member 300 is attached to the second frame 200 by inserting the boss 310B 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, which will be described later. It is a member for the purpose, and is provided in the second frame 200. The first pressing portion 600 has 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 comes into contact with the head guide 800 provided in the main body housing 10 (drum support member) when the exposure head 40 is in the exposure position, and is a member that comes into contact with the contact member main body 611 and a pair of extensions. It has a part 612 integrally.

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

The contact member 610 is arranged on the guide portion 260 provided in the second frame 200, so that the contact member 610 is supported so as to be movable in the front-rear direction with respect to the second frame 200. The guide portion 260 has upper and lower and left and right 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 abutting member 610 is pushed into the guide portion 260 from the front side, the abutting member 610 enters the guide portion 260 while the extending portion 612 is elastically deformed due to the inclination of the claw 613. Then, after the claw 613 passes through the guide wall 261, the shape of the extending portion 612 returns to the original shape, so that the contact member 610 is arranged on the guide portion 260 and the claw 613 is caught 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 in the exposure position. The spring member 620 is, for example, a compression coil spring, and is arranged 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 arranged outside the exposure range ER of the exposure head 40 in the direction of the rotation axis. Further, the first pressing portion 600 is arranged outside the interval adjusting member 300 in the direction of the rotation axis.

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 abutting the second frame 200 when the exposure head 40 is in 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 unit 710 and the third reference unit 730 are arranged so as 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. They are arranged so as to face each other. In other words, the first reference unit 710 and the third reference unit 730 are arranged on the same side in the left-right direction. Further, the second reference unit 720 is arranged on the side opposite to the first reference unit 710 and the third reference unit 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 5, the second reference portion 720 is arranged 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 located on the side opposite to the side where the first reference portion 710 and the third reference portion 730 are arranged with respect to the edges 230 and 250 with respect to the second edge portion 240 in the front-rear direction. Have been placed.

As shown in FIG. 4, the first reference portion 710 and the third reference portion 730 are provided so as to project toward the front side from the positioning portion 701 provided in the main body housing 10. 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 in the exposure position.

The first reference unit 710 and the third reference unit 730 are arranged apart from each other in the vertical direction. Specifically, the first reference unit 710 is arranged on the upper side, and the third reference unit 730 is arranged on the lower side. More specifically, the third reference unit 730 is arranged on the downstream side, specifically, 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 unit 710 has a first main body side contact surface 711 that the first head side contact surface 231 of the first edge portion 230 provided on the second frame 200 comes into contact with, and is a third reference unit. The 730 has a third main body-side contact surface 731 to which the third head-side contact surface 251 of the third edge portion 250 contacts. The first main body side contact surface 711 and the third main body side contact surface 731 are convex curved surfaces having a substantially arc shape when viewed from the direction of the rotation axis.

The head guide 800 is a member for guiding the exposure head 40 that moves from the retracted position to the exposure position. The head guide 800 is arranged on the front side of the positioning unit 701 so as to face the positioning unit 701. The exposure head 40 is arranged between the positioning unit 701 and the head guide 800 when it is in the exposure position.

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. It has a surface 830. The first guide surface 810, the second guide surface 820, and the third guide surface 830 are inclined surfaces that are located on the front side toward the upper side when viewed from the direction of the rotation axis. The inclination angles of the first guide surface 810, the second guide surface 820, and the third guide surface 830 in the vertical direction increase in this order.

As shown in FIG. 5, the second reference portion 720 has a second main body side contact surface 721 to which the second head side contact surface 241 of the second edge portion 240 provided on the second frame 200 contacts. ing. Like 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 convex curved surface having a substantially arc shape when viewed from the direction of the rotation axis.

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

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 on the main body housing 10. A protruding portion 911 that projects 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 located on the rear side toward the upper side. The torsion spring 920 is a member that applies a clockwise urging force to the rotating arm 910 in FIG.

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

In the present embodiment, the second pressing unit 900 presses the second frame 200 toward the second reference unit 720, and the first pressing unit 600 presses the second frame 200 against the first reference unit 710 and the third reference unit 720. 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 arranged.

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 and the first edge portion 230 of the second frame 200 The third edge portion 250 is pressed toward the rear side where the first reference portion 710 and the third reference portion 730 are arranged.

Next, the operation when the exposure head 40 is moved 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 of FIG. 2 to the closed position of FIG. 1, the exposure head 40 moves downward as shown in FIG. 6, and first, the third edge portion 250 The lower end portion 252 of the head guide 800 abuts on the third guide surface 830 of the head guide 800, as shown by the alternate long and short dash line.

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

Then, as shown in FIG. 8, as 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 presses the spring member 620. While compressing, it enters the guide section 260. At this time, when the contact member 610 presses the first guide surface 810 by the urging force of the spring member 620, the second frame 200 is urged to the rear side by the reaction force, and the third edge portion 250 is the third. The head-side contact surface 251 comes into contact with the third main body-side contact surface 731 of the third reference portion 730.

In the operation up to this point, the second edge portion 240 is in a free state in which it has not yet entered between the second reference portion 720 and the protruding portion 911 of the second pressing portion 900. After that, as shown in FIG. 4, when the exposure head 40 is further moved downward, the pressing force of the first pressing portion 600 causes the first head-side contact surface 231 of the first edge portion 230 to become the first reference portion 710. It abuts on the first main body side contact 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 lower end portion 242 of the second edge portion 240 is inclined at the protruding portion 911. By pushing the surface, the rotating arm 910 is rotated counterclockwise in FIG. 5 while resisting the urging 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 portion 240 comes into contact with the second main body-side contact surface 721 of the second reference portion 720 due to the pressing force of the second pressing portion 900.

Then, as shown in FIG. 3, the exposure head 40 reaches the exposure position when the interval adjusting member 300 comes into contact with the contact surface 531 of the rotation support member 500, from the lens array 102 to the photoconductor drum 51. The distance in the optical axis direction will be specified.

Based on the above, the following effects can be obtained in the present embodiment.
Since the first reference unit 710 is arranged on the rear side with respect to the second frame 200 and the second reference unit 720 is arranged on the front side with respect to the second frame 200, the degree of freedom in the arrangement of the reference unit 700 is improved. Can be made to. As a result, the degree of freedom in designing the configuration around the exposure head 40 can be improved. For example, in a configuration in which the process cartridge PC can be attached and detached, it becomes easy to arrange the second pressing portion 900 or the like at a position where the guide for attaching and detaching the cartridge is provided in the main body housing 10 and does not interfere with the guide.

Further, 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 direction of the rotation axis, the second frame 200 and the reference portion 700 are in linear or point contact. Can be made to. As a result, the second frame 200 can be brought into contact with the 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. Further, 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 it has three reference portions 700 (710, 720, 730), the second frame 200 and the reference portion 700 can be brought into contact with each other at three points. As a result, the position of the exposure head 40 in the front-rear direction can be accurately determined.

Further, since the first reference unit 710 is arranged upstream of the second reference unit 720 in the moving direction from the retracted position of the exposure head 40 to the exposure position, 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 moving 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 urging force of the spring member 620, and then the second pressing portion is operated. The rotating arm 910 of 900 can be operated against the urging force of the torsion spring 920. That is, the pressing portions 600 and 900 can be operated one by one. As a result, the resistance when moving the exposure head 40 becomes smaller as compared with the case where both pressing portions are operated at the same time, so that the exposure head 40 can be moved toward the exposure position with a small force.

Further, since the cover 11 that supports the exposure head 40 is rotatable about the rotation shaft 11A, by rotating the cover 11, the exposure head 40 is set to the exposure position along the rotation locus of the cover 11. It can be moved to and from the retracted position.

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

Further, the position where the third edge portion 250 arranged on the downstream side of the first edge portion 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 first edge portion 230 on the upstream side. When the exposure head 40 moves from the retracted position to the exposure position, the third edge portion 250 that first approaches the first reference portion 710 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 pressing portion for pressing the second frame 200 toward the reference portions 710 and 730 in the main body housing 10. As a result, the degree of freedom in designing the color printer 1 can be improved. For example, when the exposure head 40 is provided with the same configuration as that of the second pressing portion 900 as the pressing portion for pressing the second frame 200 toward the reference portions 710 and 730, the exposure head 40 is provided in one of the rotation axis directions of the exposure head 40. It is necessary to consider the arrangement and shape so as not to interfere with other members around the above, but according to the present embodiment, such restrictions can be eliminated.

Further, since the first pressing portion 600 is provided not in the first frame 100 that supports optical components such as the LED array 101 and the lens array 102, but in the second frame 200 provided separately from the first frame 100. The force of the first pressing portion 600 pressing 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. As a result, deformation of the first frame 100 and the like can be suppressed, so that the photoconductor drum 51 can be satisfactorily exposed by the LED array 101 and the lens array 102.

Further, since the contact member 610 of the first pressing portion 600 that comes into contact with the reference portions 710 and 730 is made of resin, the slidability between the first pressing portion 600 and the reference portions 710 and 730 of the main body housing 10 is improved. Can be enhanced. As a result, the exposure head 40 can be smoothly moved between the exposure position and the retracted position.

Further, since the second frame 200 has a guide portion 260 for guiding the movement of the contact member 610, the contact member 610 can be moved stably as compared with a configuration without the guide portion. As a result, the contact member 610 can accurately press the second frame 200 of the exposure head 40 toward the reference portions 710 and 730, 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 portion 600 and the second pressing portion 900 are arranged outside the exposure range ER of the exposure head 40 in the rotation axis direction, the pressing portions 600 and 900 use the second frame 200 as the reference portion 700. It is possible to suppress the force of pressing toward the exposure head 40 from acting within the exposure range ER of the exposure head 40. As a result, it is possible to prevent the force of the pressing portions 600 and 900 from pressing the second frame 200 from affecting the exposure range ER of the exposure head 40, so that the exposure head 40 can satisfactorily expose the photoconductor drum 51. it can.

The present invention is not limited to the above embodiment, and can be used in various forms as illustrated below. In the following description, members having substantially the same structure as that of the above embodiment are designated by the same reference numerals, and the description thereof will be omitted.

In the above embodiment, the head-side contact surface 231,241,251 is a flat surface and the main body-side contact surface 711,721,731 is a curved surface, but the present invention is not limited to this, and the head-side contact surface is used. It may be a curved surface and the contact surface on the main body side may be a flat surface. Further, 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 embodiment, the exposure head 40 has a structure including two frames 100 and 200 as a head frame, but the structure is not limited to this, and the exposure head may have a structure including one frame as a head frame. In this case, an optical component such as a light emitting portion, an interval adjusting member, and a first pressing portion may be provided on one frame.

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

In the above embodiment, the compression coil spring SP is exemplified as the urging member, but the urging member is not limited to this, and the urging member may be, for example, a leaf spring or a torsion spring. The same applies to the spring member of the first pressing portion.

In the above embodiment, the interval adjusting member 300 (contact portion) is in contact with the rotation support member 500, but the structure is not limited to this, and for example, the contact portion may be in contact with the drum frame. Further, the structure may be such that the contact portion abuts on the main body housing. Further, in the above embodiment, the exposure head 40 is provided with a contact portion by attaching the interval adjusting member 300 to the second frame 200, but the present invention is not limited to this, and for example, the contact portion is the head of the exposure head. It may be a part of a frame or the like.

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

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

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

In the above embodiment, the reference portion 700 is provided in the main body housing 10, but the present invention is not limited to this, and for example, the reference portion may be provided in a drum frame or the like. Further, the reference portion may be provided on a drawer or the like that supports the photoconductor drum and is movable with respect to the main body housing. In other words, the drum support member may be configured to have a drawer.

In the above embodiment, the first pressing portion 600 as the pressing portion is provided only at one end of the exposure head 40 in the rotation axis direction, but the present invention is not limited to this, and for example, the pressing portion is exposed in the rotation axis direction. It may be provided at both ends of the head. Further, 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, but the present invention is not limited to this, and the present invention may be applied to other image forming devices such as a copier and a multifunction device.

In addition, each element described in the above-described embodiment and modification may be arbitrarily combined and implemented.

1 Color printer 10 Main body housing 40 Exposure head 51 Photoreceptor drum 100 1st frame 101 LED array 102 Lens array 200 2nd frame 260 Guide part 300 Interval adjustment member 500 Rotational support member 600 1st pressing part 610 Contact member 620 Spring Member 700 Reference part 710 1st reference part 711 1st main body side contact surface 720 2nd reference part 721 2nd main body side contact surface 730 3rd reference part 731 3rd main body side contact surface

Claims (6)

Photoreceptor drum and
A drum support member that supports the photoconductor drum and
A plurality of light emitting parts arranged in the direction of the rotation axis of the photoconductor drum, an optical member for forming an image of light from the light emitting part on the surface of the photoconductor drum, and a head frame for supporting the light emitting part and the optical member. An exposure head that can move between an exposure position for exposing the photoconductor drum and a retracted position farther from the photoconductor drum than the exposure position.
The drum support member abuts on the exposure head when the exposure head is in the exposure position, so that the position of the exposure head in the sub-scanning direction orthogonal to both the optical axis direction and the rotation axis direction can be determined. It has a reference part to decide
Said head frame, have a pressing portion for pressing the head frame to the reference portion,
The pressing portion has a resin contact member that contacts the drum support member and a spring member that presses the contact member toward the drum support member.
The head frame is an image forming apparatus including a guide portion for guiding the movement of the contact member in the sub-scanning direction. The image forming apparatus according to claim 1, wherein the reference portion has a convex curved surface when viewed from the direction of the rotation axis. The reference portion has 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.
The image forming apparatus according to claim 1 or 2, wherein the first reference unit and the third reference unit are arranged apart from each other in the optical axis direction. The head frame has a first frame that supports the light emitting portion, the optical member, and a second frame that supports the first frame.
The image forming apparatus according to any one of claims 1 to 3, wherein the pressing portion is provided on the second frame. The image forming apparatus according to any one of claims 1 to 4 , wherein the pressing portion is arranged outside the exposure range of the exposure head in the direction of the rotation axis. The exposure head has an abutting portion that abuts on the drum support member and defines the distance in the optical axis direction from the optical member to the photoconductor drum.
The image forming apparatus according to any one of claims 1 to 5 , wherein the pressing portion is arranged outside the contact portion in the direction of the rotation axis.

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