JP4586877B2 - Image forming apparatus - Google Patents

Description

  The present invention relates to an image forming apparatus such as an electrophotographic printer.

2. Description of the Related Art Image forming apparatuses such as printers that employ an LED exposure method have been provided.
An image forming apparatus that employs an LED exposure method includes, for example, a process cartridge having a photosensitive belt and an image exposure unit for exposing the outer peripheral surface of the photosensitive belt (for example, Patent Document 1). reference). A door for attaching / detaching the process cartridge to / from the apparatus is provided on the front surface of the image forming apparatus. The image exposure means is separated from the photosensitive belt in conjunction with the opening of the door and retracts from the process cartridge attachment / detachment path. Specifically, the image exposure means is housed in the guide device so as to be movable up and down. In a state where the door is closed, the image exposure means is arranged at a position where the tip end portion is close to the peripheral surface of the photosensitive belt. When the door is opened, in conjunction with this, the image exposure means moves downward in the guide device and is disposed at a position retracted from the process cartridge attachment / detachment path.
Japanese Patent Laid-Open No. 4-212973

  However, in such a configuration, since the image exposure means is linearly moved in the guide device, it is necessary to secure a large space in the device for arranging the guide device. In other words, on the side where the image exposure means is disposed with respect to the process cartridge, a space for completely accommodating the image exposure means in a state where the image exposure means is retracted from the attachment / detachment path of the process cartridge is required. As a result, the size of the image forming apparatus is increased.

  Accordingly, an object of the present invention is to provide an image forming apparatus capable of reducing the space for retracting the exposure member from the photosensitive member.

In order to achieve the above object, according to a first aspect of the present invention, in an image forming apparatus, an apparatus main body, a photoconductor disposed in the apparatus main body, a photoconductor provided in the apparatus main body, and the photoconductor An exposure unit having an exposure head for exposure, and an exposure unit provided to be displaceable between an exposure posture in which the exposure head faces the photosensitive member and a retracted posture in which the exposure head is retracted from the photosensitive member; A reading unit for reading the read image, and a support member that is provided between the apparatus main body and the reading unit and supports the reading unit, and at least a part of the exposure unit is formed of the support member. housed within, the photosensitive member has a plurality provided in parallel in the detachable direction, the exposure head, in correspondence with each of the photosensitive member, provided in a plurality in parallel with the detachable direction, a plurality of In serial exposure head, farthest the exposure heads arranged in a position from the mounting port, as compared to other of said exposure head, and wherein the movement amount with respect to the photosensitive member is small.

According to a second aspect of the present invention, there is provided a photosensitive unit according to the first aspect of the invention, wherein the photosensitive member unit is detachably mounted in the apparatus main body through an attachment / detachment port formed in the apparatus main body. The photoconductor is provided in the photoconductor unit.
According to a third aspect of the present invention, in the second aspect of the present invention, the exposure unit moves the exposure head to the photoconductor in a direction crossing a direction in which the photoconductor unit is attached to or detached from the apparatus main body. It is characterized by having an advance / retreat mechanism for advancing / retreating.

According to a fourth aspect of the present invention, in the invention of the third aspect, the cover is connected to the cover for opening and closing the attachment / detachment opening, the cover and the advance / retreat mechanism, and in conjunction with the opening of the cover, The advancing / retreating mechanism includes a power transmission mechanism that transmits power for retracting the exposure head from the photosensitive member.
According to a fifth aspect of the present invention, in the invention according to the third or fourth aspect, the advance / retreat mechanism includes a fixed shaft whose axis is fixed to the apparatus main body, and one end portion of which is the axis of the fixed shaft. A first arm rotatably supported around the axis, a moving shaft whose axis is movable with respect to the apparatus main body, one end holding the exposure head, and the other end via the moving shaft A second arm connected to the one end of the first arm and swingable about an axis of the moving shaft, and the one end of the second arm is formed by the exposure unit. In the state of being in the retracted position, it is directed in a separating direction away from the attachment / detachment port.

According to a sixth aspect of the present invention, in the fifth aspect of the present invention, when the exposure unit is displaced from the exposure posture to the retracted posture, the moving shaft is in a direction opposite to the separation direction. It is characterized by being moved toward.
According to a seventh aspect of the present invention, in the invention according to any one of the third to sixth aspects, the apparatus main body is provided with an arcuate guide portion for guiding the advance / retreat of the exposure head. The photoconductor unit includes a developing device for supplying a developer to the photoconductor, and the developing device has an outer shape that avoids a moving path of the exposure head guided by the guide portion. It is characterized by that.

The invention according to claim 8 is the invention according to any one of claims 5 to 7, further comprising a biasing member that biases the exposure head toward the photoconductor. Yes.
According to a ninth aspect of the present invention, in the image forming apparatus according to the eighth aspect, the urging member is interposed between the first arm and the second arm.

According to a tenth aspect of the present invention, in the ninth aspect of the invention, the other end of the second arm is supported to be swingable with respect to the moving shaft, and the biasing member is It is characterized by being interposed between the moving shaft and the second arm.
The invention according to claim 11 is the invention according to claim 9, wherein the first gear that rotates integrally with the fixed shaft has gear teeth on a part of the circumference, Gear teeth mesh with the first gear to transmit power for moving the exposure head forward and backward to the first gear, and the exposure head is closest to the photoconductor, and the And a second gear (sector gear, tooth-missing gear) for releasing the meshing of the gear teeth, and the urging member is interposed between the apparatus main body and the first arm. .

According to the first aspect of the present invention, the photoconductor is disposed in the apparatus main body. An exposure unit having an exposure head for exposing the photosensitive member is provided in the apparatus main body. The exposure unit can be displaced between an exposure posture in which the exposure head faces the photoconductor and a retracted posture in which the exposure head is retracted from the photoconductor. In addition, the image forming apparatus includes a reading unit for reading an image formed on a document. A support member for supporting the reading unit is provided between the reading unit and the apparatus main body. Then, at least a part of the exposure unit is accommodated in the support member. Therefore, it is not necessary to secure a space for a portion of the exposure unit that is accommodated in the support member in the exposure apparatus unit. Therefore, the space required for retracting the exposure head from the photosensitive member in the apparatus main body can be reduced by the space.
A plurality of photoconductors are provided in parallel in the attaching / detaching direction. Further, a plurality of exposure heads are provided in parallel in the attaching / detaching direction with respect to each photoconductor. Thus, even when a plurality of photosensitive members and exposure heads are provided, at least a part of each exposure unit is accommodated in the support member, so that a space for retracting the exposure head from the photosensitive member in the apparatus main body is obtained. Can be reduced.
In addition, in the plurality of exposure heads, the exposure head disposed at the position farthest from the attachment / detachment opening has a smaller amount of movement relative to the photoconductor than other exposure heads. Thereby, the space in the retracting direction (downstream in the direction intersecting with the attaching / detaching direction of the photoconductor unit) of the exposure member arranged at the position farthest from the attaching / detaching port can be effectively used.

  According to the second aspect of the present invention, the photosensitive unit is mounted in the apparatus main body. The photoconductor unit can be attached to and detached from the apparatus main body through an attachment / detachment opening formed in the apparatus main body. The photoconductor unit includes a photoconductor. Thus, even when the photosensitive unit is detachable from the apparatus main body, the space for retracting the exposure head from the photosensitive member in the apparatus main body can be reduced.

According to a third aspect of the present invention, the exposure unit includes an advance / retreat mechanism. The advance / retreat mechanism can advance and retract the exposure head relative to the photoreceptor in a direction that intersects with the attachment / detachment direction of the photoreceptor unit with respect to the apparatus body.
According to invention of Claim 4, the cover which opens and closes an attachment / detachment opening is provided. A power transmission mechanism is coupled to the cover and the advance / retreat mechanism. The power transmission mechanism transmits power for retracting the exposure head from the photosensitive member to the advance / retreat mechanism in conjunction with opening of the cover. Thereby, the exposure head can be retracted from the photosensitive member in conjunction with the opening of the cover.

  According to the invention described in claim 5, the advance / retreat mechanism includes a fixed shaft whose axis is fixed to the apparatus main body, and a first arm whose one end is supported so as to be rotatable around the axis of the fixed shaft. A movement axis whose axis is movable relative to the apparatus main body, one end holding the exposure head, and the other end connected to one end of the first arm via the movement axis. A second arm swingably provided at the center. Thereby, the 1st arm and the 2nd arm can be bent and extended so that one end of the 2nd arm may approach or separate from the 1st arm. While moving the moving shaft, the one end of the second arm is brought close to the first arm, whereby the exposure head held on the one end of the second arm can be retracted from the photoreceptor. As a result, a portion of the exposure unit that is not accommodated in the support member can be accommodated in a direction intersecting with the attaching / detaching direction of the photoreceptor unit in the apparatus main body, with one end of the second arm being close to the first arm. As long as the space is secured, the space for retracting the exposure head from the photosensitive member can be further reduced. Further, one end of the second arm is directed in a separation direction away from the attachment / detachment opening in a state where the exposure unit is in the retracted posture. Thus, the exposure head is not exposed toward the attachment / detachment port side of the apparatus main body, and it is possible to prevent the exposure head from being scratched or dusted.

According to the sixth aspect of the present invention, when the exposure unit is displaced from the exposure posture to the retracted posture, the moving shaft is moved in the direction opposite to the separation direction. Thereby, when the exposure head is retracted from the photosensitive member, one end portion of the second arm is directed in the separating direction, and the other end portion of the second arm is disposed in the direction opposite to the separating direction.
According to the invention described in claim 7, the apparatus main body is provided with the arc-shaped guide portion. The exposure head advances and retreats while being guided by the guide unit. The photoconductor unit includes a developing device for supplying a developer to the photoconductor. The developing device has an outer diameter that avoids the movement path of the exposure head guided by the guide portion. Thereby, it is possible to prevent the exposure head from coming into contact with the developing device when the exposure head is guided by the arcuate guide portion and moved forward and backward.

According to the eighth aspect of the present invention, the image forming apparatus further includes a biasing member that biases the exposure head toward the photosensitive member. As a result, the exposure head receives a biasing force from the biasing member and positions the photosensitive member at a position where exposure is possible.
According to the ninth aspect of the present invention, the urging member is interposed between the first arm and the second arm. Accordingly, the second arm can be biased toward the photoconductor, and the exposure head attached to one end of the second arm can be positioned at a position where the photoconductor can be exposed.

According to the invention described in claim 10, the other end of the second arm is supported so as to be swingable with respect to the moving shaft. The urging member is interposed between the moving shaft and the second arm. Accordingly, the second arm can be biased toward the photoconductor, and the exposure head attached to one end of the second arm can be positioned at a position where the photoconductor can be exposed.
According to the eleventh aspect of the present invention, the image forming apparatus includes the first gear and the second gear. The first gear rotates integrally with the fixed shaft. The second gear has gear teeth on a part of the circumference, and the gear teeth mesh with the first gear to transmit power to advance and retract the exposure head to the first gear. With the exposure head closest to the photoreceptor, the meshing of the gear teeth with the first gear is released. The urging member is interposed between the apparatus main body and the first arm. When the exposure head is closest to the photoconductor, the meshing of the gear teeth of the second gear with respect to the first gear is released. In this state, the first arm is biased, whereby the exposure head can be positioned at a position where the photosensitive member can be exposed.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.
1. 1 is a side sectional view of a printer as an example of an image forming apparatus according to an embodiment of the present invention.
The printer 1 is a so-called multi-function machine including a device main body 2 formed in a box shape and a flat bed scanner 4 as an example of a reading unit supported on the device main body 2 by a support member 3.
(1) Apparatus Main Body In the apparatus main body 2, a drum unit 6 as an example of a photoconductor unit is mounted. The drum unit 6 includes a photosensitive drum 8 as an example of photosensitive members of four colors of black, yellow, magenta, and cyan. The four-color photosensitive drums 8 are arranged at equal intervals in the conveyance direction of the paper P by the conveyance belt 20 described later. Further, the drum unit 6 is provided with a drum subunit 9 and a developing cartridge 10 as an example of a developing unit corresponding to each photosensitive drum 8.

Further, an LED unit 24 as an example of an exposure unit is provided in the apparatus main body 2 corresponding to each photosensitive drum 8.
As the photosensitive drum 8 rotates, the surface of the photosensitive drum 8 is uniformly charged by the scorotron charger 11 provided in the drum subunit 9 and then selectively exposed by the light from the LED unit 24. Is done. By this exposure, an electrostatic latent image based on the image data is formed on the surface of the photosensitive drum 8. When the electrostatic latent image faces the developing roller 16 provided in the developing cartridge 10 as the photosensitive drum 8 rotates, toner is supplied from the developing roller 16 to the electrostatic latent image, and the electrostatic latent image is converted into the toner by the toner. Visualized. As a result, a toner image is formed on the surface of the photosensitive drum 8.

  At the bottom of the apparatus main body 2, a paper feed cassette 19 that stores paper P is disposed. The paper P stored in the paper feed cassette 19 is transported onto the transport belt 20 by various rollers. The conveyor belt 20 is disposed to face the four photosensitive drums 8 from below. A transfer roller 21 is disposed at each position facing the photosensitive drum 8 across the upper portion of the conveyance belt 20. The paper P transported on the transport belt 20 sequentially passes between the transport belt 20 and each photosensitive drum 8 as the transport belt 20 travels. The toner image on the surface of the photosensitive drum 8 is transferred onto the paper P by the transfer bias applied to the transfer roller 21 when facing the paper P.

A fixing device 22 is provided on the downstream side in the conveyance direction of the paper P with respect to the conveyance belt 20. The paper P on which the toner image is transferred is conveyed to the fixing device 22. In the fixing device 22, the toner image is fixed on the paper P by heating and pressing. The paper P on which the toner image is fixed is discharged to a paper discharge tray 23 on the upper surface of the main body casing 2 by various rollers.
In the following description, the upstream side in the conveyance direction of the paper P by the conveyance belt 20 is the front side (front side), and the downstream side opposite to the upstream side is the rear side (back side). In addition, when the printer 1 is viewed from the front side, the left and right reference is used.
(2) Support Member FIG. 3 is a cross-sectional view of the printer shown in FIG. 1 taken along line III-III.

As shown in FIG. 3, the support member 3 is provided integrally with the apparatus main body 2 above the apparatus main body 2. The support member 3 has a pair of leg portions 28 that face each other in the left-right direction and extend in the front-rear direction. The lower ends of the pair of leg portions 28 are connected by a paper discharge tray 23. In FIG. 1, the leg portion 28 is indicated by a virtual line.
Each leg portion 28 is formed so as to be opened downward, and the inner space is used as a housing space for housing at least a part of the LED unit 24.
(3) Flatbed Scanner The flatbed scanner 4 includes a document table 31 fixed to the support member 3 and a presser cover 32 supported on the document table 31 through a hinge 34 so as to be swingable.

The document table 31 is formed in a rectangular plate shape in plan view. A platen glass 33 on which a document is placed is provided on the upper surface of the document table 31. Inside the document table 31, a CCD sensor (not shown) for reading an image of a document placed on the platen glass 33 is provided below the platen glass 33.
2. Front Cover FIG. 2 is a side sectional view showing a state in which the front cover is opened in the printer shown in FIG.

An attachment / detachment port 7 is formed on the front surface of the apparatus main body 2. In addition, a front cover 5 as an example of a cover is provided on the front surface of the apparatus main body 2 so that the attachment / detachment port 7 can be opened and closed. Specifically, a cover shaft 26 extending in the left-right direction below the attachment / detachment port 7 is provided at the front end of the apparatus main body 2. One end of a cover arm 27 that is substantially U-shaped in a side view is rotatably supported on the cover shaft 26. The other end of the cover arm 27 is fixed to the inner surface of the lower end portion of the front cover 5. As a result, the front cover 5 is supported by the cover arm 27 and is rotatably provided integrally with the cover arm 27 with the cover shaft 26 as a fulcrum. The front cover 5 is closed along the front surface of the apparatus main body 2 (the state shown in FIG. 1), closes the attachment / detachment port 7, and is tilted forward of the apparatus main body 2 (the state shown in FIG. 2). The attachment / detachment port 7 is opened.
3. Drum Unit The drum unit 6 can be attached to and detached from the apparatus main body 2 through the attachment / detachment opening 7 by sliding in the front-rear direction with the attachment / detachment opening 7 being opened. That is, the drum unit 6 can be mounted in the apparatus main body 2 by opening the attachment / detachment opening 7 and pushing the drum unit 6 toward the apparatus main body 2 (rearward). Further, the drum unit 6 can be detached from the apparatus main body 2 by opening the attachment / detachment opening 7 and pulling the drum unit 6 forward from the apparatus main body 2.

  The drum unit 6 includes a pair of side plates 25 that sandwich the four photosensitive drums 8, the four drum subunits 9, and the four developing cartridges 10 from the left and right. The side plate 25 is formed in a substantially elongated rectangular plate shape in side view extending in the front-rear direction. At the rear end portion of the side plate 25, a notch 40 having a substantially V shape in side view is formed. When the drum unit 6 is mounted in the apparatus main body 2, the reference shaft 41 laid in the left-right direction at the rear end of the apparatus main body 2 fits into the notch 40, and the positioning of the drum unit 6 with respect to the apparatus main body 2 is achieved. Is done. Further, four positioning grooves 42 are formed at equal intervals in the front-rear direction at the upper end of the side plate 25. Each positioning groove 42 corresponds to each photosensitive drum 8, and is formed by cutting the side plate 25 into a substantially straight line extending from the upper edge of the side plate 25 toward the rotation center of the corresponding photosensitive drum 8.

  Between the pair of side plates 25, the four photosensitive drums 8 are arranged at equal intervals in the front-rear direction. Each photosensitive drum 8 extends in the left-right direction, and both end portions thereof are rotatably held by the side plate 25. A drum subunit 9 corresponding to the photosensitive drum 8 is arranged behind each photosensitive drum 8. Each drum subunit 9 extends in the left-right direction, and both end portions thereof are fixed to the side plate 25.

  The four developing cartridges 10 are detachably mounted in front of each photosensitive drum 8 between a pair of side plates 25. The developing cartridge 10 includes a box-shaped casing 13 having an opening at one end. At one end of the housing 13, the developing roller 16 is rotatably held with a part of its peripheral surface exposed. The developing cartridge 10 is mounted between a pair of side plates 25 from the upper front side of the corresponding photosensitive drum 8 so that the peripheral surface of the developing roller 16 contacts the peripheral surface of the photosensitive drum 8. In this mounted state, the housing 13 extends in the up-down direction and protrudes greatly upward from the upper end edge of the side plate 25. And the upper end part (part which protruded upwards rather than the upper end edge of the side plate 25) in the housing | casing 13 is formed in the substantially rectangular parallelepiped shape in which the rear surface was slightly depressed ahead. Thereby, the housing | casing 13 has the external shape which avoided the movement path | route of the LED head 18 guided to the guidance part 71 mentioned later.

In the drawing, only the outer shape of the side plate 25 is shown, and the photosensitive drum 8, the developing roller 16, and the like are shown through the side plate 25.
4). LED Unit The four LED units 24 are provided in parallel in the front-rear direction corresponding to each photosensitive drum 8. Each LED unit 24 includes an LED head 18 as an example of an exposure head for exposing the surface of the photosensitive drum 8, and a pair of left and right advance / retreat mechanisms 51 for moving the LED head 18 forward and backward with respect to the photosensitive drum 8. It has.

In the drawing (FIG. 1 and the like), the paper discharge tray 23 and the like are shown through the LED unit 24.
(1) LED head The LED head 18 incorporates an LED array (not shown) having a configuration in which a large number of LEDs are arranged in the left-right direction. Positioning bosses 43 projecting outward are provided at the left end and the right end of the LED head 18, respectively.

The distal ends of the left and right positioning bosses 43 are fitted into groove-shaped guide portions 71 formed on the left and right side plates of the apparatus main body 2, respectively. Four guide portions 71 are formed on each side plate of the apparatus main body 2 corresponding to each positioning groove 42. Each guide portion 71 has a gentle arc shape whose lower end portion overlaps with the corresponding positioning groove 42 in a side view, extends upward in the front side, and has a convex rear side.
(2) Advance / Retreat Mechanism The left / right pair of advance / retreat mechanisms 51 are connected to the left end and the right end of the LED head 18, respectively. A pair of right and left is provided at each right end. Each advance / retreat mechanism 51 includes a fixed shaft 52, a first arm 53, a moving shaft 54, and a second arm 55.

The fixed shafts 52 of the pair of left and right advance / retreat mechanisms 51 are respectively installed on the left and right legs 28 of the support member 3 and are disposed on a common fixed axis extending in the left-right direction. Since the four LED units 24 are provided in parallel in the front-rear direction, four fixed shafts 52 are arranged in parallel in the front-rear direction at equal intervals in each leg portion 28.
An input gear 56 fixed to one end portion of the first arm 53 described below is rotatably supported on the fixed shaft 52 disposed at the forefront in the right leg portion 28. In addition, a transmission gear 59 fixed to one end of the first arm 53 is rotatably supported on the fixed shaft 52 arranged at the rearmost position in the left and right leg portions 28.

The first arm 53 is formed in an elongated rod shape. The first arm 53 is swingably provided about the axis of the fixed shaft 52 by having one end (base end) of the first arm 53 supported rotatably on the fixed shaft 52.
The axis of the moving shaft 54 extends in the left-right direction, and is provided at the tip of the first arm 53 (the end opposite to the end supported by the fixed shaft 52) so as not to rotate. Accordingly, the moving shaft 54 moves along an arcuate locus centering on the axis of the fixed shaft 52 by the swing of the first arm 55.

  The second arm 55 is formed in a bar shape that is slightly shorter than the first arm 53. The base end of the second arm 55 is rotatably supported by the moving shaft 54. More specifically, an opening extending in the longitudinal direction of the second arm is formed at the base end portion of the second arm 55, and the moving shaft 54 is rotatably inserted into the opening. Thereby, the second arm 55 is provided so as to be able to swing around the axis of the moving shaft 54. The LED head 18 is held between the distal ends of the second arms 55 of the pair of left and right advance / retreat mechanisms 51 so as to extend in the left-right direction.

  A coil spring 57 as an example of an urging member is provided in the opening formed at the other end of the second arm 55. One end of the coil spring 57 is fixed to the moving shaft 54, and the other end is fixed to the tip edge of the opening. That is, the coil spring 57 is interposed between the moving shaft 54 and the tip edge of the opening. Due to the urging force of the coil spring 57, the second arm 55 is urged in a direction in which the tip end portion is separated from the moving shaft 54.

On each of the left and right sides of the four LED units 24, the four moving shafts 54 arranged in the front-rear direction pass through a connecting member 58 that is elongated in a side view extending in the front-rear direction and is connected by the connecting member 58. ing. For this reason, the four moving shafts 54 connected by the connecting member 58 move while drawing an arcuate locus centering on the axis of the fixed shaft 52 while maintaining a parallel state to each other.
5). Power transmission mechanism A power transmission mechanism 61 is interposed between the front cover 5 and the input gear 56 to transmit power for operating the advance / retreat mechanism 51 to the input gear 56 in conjunction with opening and closing of the front cover 5. Yes.

The power transmission mechanism 61 includes a rack gear 62 and an even number (four in this embodiment) of gears 63 interposed between the rack gear 62 and the input gear 56.
The rack gear 62 is formed in a substantially ¼ arc shape in a side view centering on the swing shaft 26 and has a large number of gear teeth on the outer peripheral surface thereof. One end of the rack gear 62 is fixed to the center in the vertical direction of the inner surface of the front cover 5.

The even number of gears 63 mesh with each other to form a single gear train. The gear 63 at one end of the gear train meshes with the rack gear 62. The gear 63 at the other end of the gear train meshes with the input gear 56.
In the drawings (FIG. 1 and the like), only the outer shape of the rack gear 62 is shown, and the side plate 25 and the like are shown through the rack gear 62.
6). Synchronizing mechanism A synchronizing mechanism 81 is connected between the left and right transmission gears 59 to synchronize the movement of the advancing / retracting mechanism 51 arranged at the rearmost position on both the left and right sides.

The synchronization mechanism 81 includes an odd number (three in this embodiment) of gears 83 that are rotatably held on the left and right side plates of the apparatus main body. The odd number of gears 83 on each of the left and right sides constitutes a single gear train and is symmetrical. A gear 83 at one end of each gear train meshes with the transmission gear 59. The synchronization mechanism 81 includes a connecting shaft 82 that connects the rotation shaft of the gear 83 at the other end of each gear train.

With this configuration, when the right transmission gear 59 rotates, the rotation is transmitted to the left transmission gear 59 by the synchronization mechanism 81, and the left transmission gear 59 rotates in the same direction as the right transmission gear 59 in a side view. To do.
7). LED Head Advancing and Retracting Operation As shown in FIG. 1, when the front cover 5 closes the attachment / detachment opening 7, each LED unit 24 takes an exposure posture. In this exposure posture, each LED unit 24 is disposed behind each developing cartridge 10 and overlaps with the developing cartridge 10 in the front-rear direction. Specifically, in each LED unit 24, the first arm 53 and the second arm 54 extend in a substantially linear shape between the fixed shaft 52 and the photosensitive drum 8, and the LED head 18 extends above the photosensitive drum 8. From the nearest. Each positioning boss 43 provided on the LED head 18 has a tip disposed at the lower end of the guide portion 71 and fits in the positioning groove 42 of the side plate 25 on the inner side in the left-right direction, and the biasing force of the coil spring 57. Is pressed against the lower end edge of the positioning groove 42. Thus, the four LED heads 18 are positioned at fixed positions with respect to the corresponding photosensitive drums 8, respectively, and the surface of the photosensitive drums 8 can be exposed satisfactorily.

  When the front cover 5 is opened, the rack gear 62 moves forward around the swing shaft 26 in accordance with the opening operation. The movement of the rack gear 62 is transmitted to the input gear 56 through a gear train composed of the gear 63. As a result, the input gear 56 rotates clockwise in the figure, and the first arm 53 fixed to the input gear 56 rotates clockwise in the figure around the fixed shaft 52 as a fulcrum, and is provided at the tip portion thereof. The moving shaft 54 (the rightmost foremost moving shaft 54) moves upward in the front side. Since the four right moving shafts 54 are connected by the connecting member 58, the connecting member 58 moves forward and upward as the right most front moving shaft 54 moves, and the right three remaining moving shafts 54 are moved. Moves upward on the front side. As a result, the four first arms 53 on the right side rotate in synchronism with each other so that the tip ends are lifted upward in the front side.

  Further, as the four first arms 53 rotate, the transmission gear 59 fixed to the rightmost first arm 53 rotates clockwise in the figure. The rotation of the right transmission gear 59 is transmitted to the left transmission gear 59 by the synchronization mechanism 81. As a result, the left transmission gear 59 rotates clockwise in the figure, and the first arm 53 fixed to the transmission gear 59 rotates clockwise in the figure around the fixed shaft 52 as a fulcrum, and is provided at the tip portion thereof. The moving shaft 54 (the leftmost moving shaft 54) moves upward in the front side. Since the left four moving shafts 54 are connected by the connecting member 58, the left three moving shafts 54 move upward in the front side in accordance with the movement of the leftmost moving shaft 54. As a result, the four first arms 53 on the left side rotate in synchronism with each other so that the tip ends are lifted upward.

That is, when the front cover 5 is opened, all the first arms 53 are rotated simultaneously with the opening operation, and all the moving shafts 54 are simultaneously moved upward in the front side.
As each moving shaft 54 moves upward in the front side, each second arm 55 is lifted upward. As each second arm 55 moves, each LED head 18 moves upward. Since the positioning boss 43 provided in each LED head 18 is fitted in the guide portion 71, the positioning boss 43 is guided by the guide portion 71 at this time, and each LED head 18 moves upward along the guide portion 71. . As described above, the moving shaft 54 moves upward in the front direction and the LED head 18 moves upward along the guide portion 71, so that the first arm 53 and the second arm 55 are connected to the distal end portion of the second arm 55 ( The LED head 18) is folded (refracted) into a V-shape facing rearward.

  As shown in FIG. 2, when the front cover 5 is completely opened, each LED unit 24 takes a retracted posture. In this retracted position, the positioning boss 43 provided on each LED head 18 is disposed at the upper end of the guide portion 71, and each LED head 18 is retracted most from the photosensitive drum 8. Accordingly, each LED unit 24 is disposed above each developing cartridge 10 and is detached from the attachment / detachment path of the drum unit 6. The left and right advancing / retracting mechanisms 51 are respectively housed in the left and right leg portions 28 in a state where the first arm 53 and the second arm 55 are folded so as to form the acute angle.

Since each LED unit 24 is detached from the attachment / detachment path of the drum unit 6, the drum unit 6 can be attached to and detached from the inside of the apparatus main body 2 without causing interference with each LED unit 24.
8). As described above, the photosensitive drum 8 is disposed in the apparatus main body 2. Further, an LED unit 24 having an LED head 18 for exposing the photosensitive drum 8 is provided in the apparatus main body 2. The LED unit 24 can be displaced between an exposure posture in which the LED head 18 faces the photosensitive drum 8 and a retracted posture in which the LED head 18 is retracted from the photosensitive drum 8. Further, the printer 1 is provided with a flat bed scanner 4 for reading an image formed on a document. A support member 3 that supports the flat bed scanner 4 is provided between the flat bed scanner 4 and the apparatus main body 2. Then, at least a part of the LED unit 24 is accommodated in the support member 3. Therefore, it is not necessary to secure a space in the apparatus main body 2 for a portion of the LED unit 24 that is accommodated inside the support member 3. Therefore, the space necessary for retracting the LED head 18 from the photosensitive drum 8 in the apparatus main body 2 can be reduced by the space.

A drum unit 6 is mounted in the apparatus main body 2. The drum unit 6 can be attached to and detached from the apparatus main body 2 through an attachment / detachment opening 7 formed in the apparatus main body 2. Even in a configuration in which the drum unit 6 is detachable from the apparatus main body 2, the space for retracting the LED head 18 from the photosensitive drum 8 in the apparatus main body 2 can be reduced.
Further, the LED unit 24 includes an advance / retreat mechanism 51. The advance / retreat mechanism 51 can advance / retreat the LED head 18 relative to the photosensitive drum 8 in a direction crossing the attaching / detaching direction of the drum unit 6 with respect to the apparatus main body 2.

  The apparatus body 2 is provided with a front cover 5 that opens and closes the attachment / detachment opening 7. A power transmission mechanism 61 is connected to the front cover 5 and the advance / retreat mechanism 51. The power transmission mechanism 61 transmits power for retracting the LED head 18 from the photosensitive drum 8 to the advance / retreat mechanism 51 in conjunction with the opening of the front cover 5. Accordingly, the LED head 18 can be retracted from the photosensitive drum 8 in conjunction with the opening of the front cover 5.

  The advancing / retreating mechanism 51 includes a fixed shaft 52 whose axis is fixed with respect to the apparatus main body 2, a first arm 53 whose one end is rotatably supported around the axis of the fixed shaft 52, and the apparatus main body 2. A movement axis 54 whose axis is movable, one end holding the LED head 18, and the other end connected to one end of the first arm 53 via the movement axis 54. And a second arm 55 provided so as to be swingable about an axis. Accordingly, the first arm 53 and the second arm 55 can be bent and extended so that one end of the second arm 55 is close to or away from the first arm 53. While moving the moving shaft 54, the one end of the second arm 55 is brought close to the first arm 53, thereby retracting the LED head 18 held on one end of the second arm 55 with respect to the photosensitive drum 8. be able to. As a result, in the direction intersecting with the attaching / detaching direction of the drum unit 6 in the apparatus main body 2, the one end of the second arm 55 is close to the first arm 53 and is not accommodated in the support member 3 in the LED unit 24. It is only necessary to secure a space that can accommodate the portion, and the space for retracting the LED head 18 from the photosensitive drum 8 can be further reduced. Further, one end of the second arm 55 is directed in a separating direction away from the attachment / detachment port 7 in a state where the LED unit 24 is in the retracted posture. Thereby, the LED head 18 is not exposed toward the attachment / detachment port 7 side of the apparatus main body 2, and it is possible to prevent the LED head 18 from being scratched or dusted.

When the LED unit 24 is displaced from the exposure posture to the retracted posture, the moving shaft 54 is moved in the direction opposite to the separation direction. Thus, when the LED head 18 is retracted from the photosensitive drum 8, one end portion of the second arm 55 is directed in the separation direction, and the other end portion of the second arm 55 is disposed in the direction opposite to the separation direction. .
Further, the apparatus main body 2 is provided with an arcuate guide portion 71. The LED head 18 advances and retreats while being guided by the guide portion 71. The drum unit 6 includes a developing cartridge 10 for supplying toner to the photosensitive drum 8. The developing cartridge 10 has an outer diameter that avoids the movement path of the LED head 18 guided by the guide portion 71. Thereby, it is possible to prevent the LED head 18 from coming into contact with the developing cartridge 10 when the LED head 18 is guided by the arcuate guide portion 71 and moved forward and backward.

The printer 1 further includes a coil spring 57 that biases the LED head 18 toward the photosensitive drum 8. Thus, the LED head 18 is positioned at a position where the photosensitive drum 8 can be exposed by receiving the urging force of the coil spring 57.
The coil spring 57 is interposed between the first arm 53 and the second arm 55. Accordingly, the second arm 55 can be urged toward the photosensitive drum 8, and the LED head 18 attached to one end of the second arm 55 can be positioned at a position where the photosensitive drum 8 can be exposed. it can.

The other end of the second arm 55 is supported so as to be swingable with respect to the moving shaft 54. The coil spring 57 is interposed between the moving shaft 54 and the second arm 55. Accordingly, the second arm 55 can be urged toward the photosensitive drum 8, and the LED head 18 attached to one end of the second arm 55 can be positioned at a position where the photosensitive drum 8 can be exposed. it can.
9. Second Embodiment FIG. 4 is a side sectional view of a printer according to another embodiment of the present invention. FIG. 5 is a side sectional view showing a state where the cover is opened in the printer shown in FIG. 4 and 5, parts corresponding to those shown in FIGS. 1 and 2 are denoted by the same reference numerals as those parts. In the following, the configuration shown in FIGS. 4 and 5 will be described with a focus on the differences from the configuration shown in FIGS. 1 and 2, and description of portions corresponding to the portions shown in FIGS. 1 and 2 will be omitted.

In the printer 1 shown in FIGS. 1 and 2, a coil spring 57 is interposed between the moving shaft 54 and the second arm 55, whereas in the printer 100 shown in FIGS. 4 and 5, the coil spring 57 is omitted. In addition, a coil spring 101 as an example of an urging member is interposed between a middle portion in the longitudinal direction of each first arm 53 and the leg portion 28 of the support member 3.
Further, a gear 63 as an example of a second gear that meshes with an input gear 56 as an example of a first gear is a missing tooth gear having a missing tooth portion 63a in which a gear tooth is not formed on a part of its peripheral surface. It has become. When the front cover 5 is closed and the LED unit 24 is in the exposure posture, the missing tooth portion 63a of the gear 63 faces the input gear 56, and the meshing between the gear 63 and the input gear 56 is released. When the gear 63 rotates from this state, the gear 63 meshes with the input gear 56, and the input gear 56 rotates as the gear 63 rotates.

Further, in each of the left and right connecting members 58, except for the moving shaft 54 at the tip of the first arm 53 fixed to the input gear 56, the other moving shafts 54 are formed in substantially rectangular through holes 102 that are long in the front-rear direction. It is inserted.
With such a configuration, when each LED unit 24 is in the exposure posture, the first arm 53 fixed to the input gear 56 is swung within a range in which the tooth missing portion 63a of the gear 63 faces the input gear 56. It is possible to move. Further, the other first arms 53 can swing within a range in which the moving shaft 54 can move within the through hole 102. Then, each first arm 53 is urged rearward by the urging force of the coil spring 101, whereby each positioning boss 43 provided on each LED head 18 is pressed against the lower end edge of the positioning groove 42. The LED heads 18 are positioned at fixed positions with respect to the corresponding photosensitive drums 8 respectively.

The configuration of the printer 100 shown in FIGS. 4 and 5 can provide the same effects as the printer 1 shown in FIGS.
Although the gear 63 meshing with the input gear 56 is a chipped gear, a sector gear may be adopted as the gear 63.
10. Third Embodiment FIG. 6 is a side sectional view of a printer according to still another embodiment of the present invention. FIG. 7 is a side sectional view showing a state where the cover is opened in the printer shown in FIG. In FIGS. 6 and 7, parts corresponding to the parts shown in FIGS. 1 and 2 are denoted by the same reference numerals as those parts. In the following, the configuration shown in FIGS. 6 and 7 will be described with a focus on the differences from the configuration shown in FIGS. 1 and 2, and description of portions corresponding to the respective portions shown in FIGS. 1 and 2 will be omitted.

  In the printer 110 shown in FIGS. 6 and 7, the rear end portions of the left and right connecting members 58 extend downward in the rear side. More specifically, the rear end portion of each connecting member 58 extends in a direction opposite to the direction in which the connecting member 58 moves when the LED unit 24 is displaced from the exposure posture to the retracted posture. A long hole 111 having a shape along the bent portion is formed in a portion extending downward on the rear side, and the moving shaft 54 of the left and right advancing / retracting mechanisms 51 is slidably inserted.

  When the front cover 5 is closed and the LED units 24 are in the exposure posture, the moving shaft 54 of the left and right advancing / retracting mechanism 51 at the rearmost position is disposed at the upper end of the long hole 111. The front cover 5 is opened, and the left and right connecting members 58 are moved upward in the front side with the opening operation. At this time, on each of the left and right sides, the front three moving shafts 54 move upward in the front side as the connecting members 58 move. On the other hand, the rearmost movement shaft 54 does not change in absolute position, and moves relatively in the long hole 111 toward the lower end portion. Therefore, the front three LED heads 18 are lifted upward, and the rearmost LED head 18 does not move from the position closest to the photosensitive drum 8.

  Then, after the rearmost moving shaft 54 is arranged at the lower end of the long hole 111, when each connecting member 58 further moves, the rearmost moving shaft 54 moves to the upper front side, and the rearmost LED head 18 moves. It is lifted upward behind the three LED heads 18 in the front. Therefore, the rearmost LED head 18 has a smaller amount of movement relative to the photosensitive drum 8 than the other LED heads 18.

  As shown in FIG. 7, with the front cover 5 fully opened, the rearmost LED unit 24 overlaps the developing cartridge 10 in the front-rear direction. However, the rearmost LED unit 24 is separated from the attachment / detachment path of the drum unit 6 because the LED head 18 is disposed above the upper end edge of the side plate 25, so that the drum unit 6 is connected to each LED unit 24. Can be attached to and detached from the inside of the apparatus main body 2 without causing interference.

As described above, the rearmost LED head 18 disposed at the position farthest from the attachment / detachment opening 7 has a smaller movement amount relative to the photosensitive drum 8 than the other LED heads 18. As a result, the space required for retracting the rearmost LED head 18 from the photosensitive drum 8 is reduced. Therefore, the apparatus size can be reduced by the space. Alternatively, it is possible to effectively use the space in the apparatus main body 2 such as arranging another member in the space.
11. Modifications For example, in each of the above-described embodiments, the synchronization mechanism 81 is omitted, the input gear 56 is also provided in the rightmost forward advancement / retraction mechanism 51, and the power transmission mechanism 61 is interposed between the input gear 56. May be.

Further, even if the connecting member 58 is omitted, gear teeth that rotate integrally with each fixed shaft 52 are attached, and a gear train for transmitting power between the fixed shafts 52 arranged in the front-rear direction is provided. Good.
In the printer 100 shown in FIGS. 4 and 5, the coil spring 101 is connected to each first arm 53, but at least one coil spring 101 is provided and connected to any one of the first arms 53. Just do it. In this case, each moving shaft 54 is inserted through the connecting member 58 without play. Thus, when the first arm 53 connected to the coil spring 101 is biased, the biasing force is transmitted to the other first arm 53 via the connecting member 58.

  In each of the above-described embodiments, the LED head 18 including a plurality of LEDs is taken up as an example of the exposure head. However, the exposure head is not limited to the LED head 18 and has other configurations including a plurality of light emitting units. Can also be adopted. The plurality of light emitting units may be composed of one light emitting element. For example, a configuration may be adopted in which one backlight such as a fluorescent lamp is prepared as a light emitting element, and an optical shutter of liquid crystal or PLZT element arranged in a line in the left-right direction is provided outside the backlight. That is, a plurality of light emitting units arranged in one row can be formed by combining one light emitting element and one row of optical shutters. In addition, the light emitting units may be arranged in a plurality of rows instead of being arranged in one row in the left-right direction. Furthermore, the light emitting element is not limited to an LED, and an EL (electroluminescence) element, a phosphor, and the like can be used.

1 is a side sectional view of a printer as an example of an image forming apparatus according to a first embodiment of the present invention. FIG. 2 is a side sectional view showing a state where a cover is opened in the printer shown in FIG. 1. FIG. 3 is a sectional view of the printer shown in FIG. 1 taken along line III-III. It is a sectional side view of the printer which concerns on the 2nd Embodiment of this invention. FIG. 5 is a side sectional view showing a state where a cover is opened in the printer shown in FIG. 4. It is a sectional side view of the printer which concerns on the 3rd Embodiment of this invention. FIG. 7 is a side sectional view showing a state where a cover is opened in the printer shown in FIG. 6.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Printer 2 Apparatus main body 5 Front cover 6 Drum unit 7 Removable opening 8 Photosensitive drum 10 Developing cartridge 18 LED head 51 Advance / retract mechanism 52 Fixed shaft 53 1st arm 54 Moving shaft 55 2nd arm 56 1st gear 57 Coil spring 61 Power transmission mechanism 63a Second gear 71 Guide portion 101 Coil spring

Claims (11)

The device body;
A photoconductor disposed in the apparatus body;
An exposure head provided in the apparatus main body and having an exposure head for exposing the photoconductor, wherein the exposure head faces the photoconductor, and a retreat posture in which the exposure head is retracted from the photoconductor An exposure unit provided to be displaceable,
A reading unit for reading an image formed on a document;
A support member provided between the apparatus main body and the reading unit and supporting the reading unit;
At least a part of the exposure unit is accommodated in the support member ;
A plurality of the photoreceptors are provided in parallel in the attachment / detachment direction,
A plurality of the exposure heads are provided in parallel in the attachment / detachment direction corresponding to each of the photoconductors,
In the plurality of exposure heads, the exposure head disposed at a position farthest from the attachment / detachment opening has a smaller movement amount relative to the photoconductor than the other exposure heads. apparatus. A photosensitive unit detachably mounted in the apparatus main body through an attachment / detachment port formed in the apparatus main body;
The image forming apparatus according to claim 1, wherein the photoconductor is provided in the photoconductor unit.   The exposure unit includes an advancing / retreating mechanism for advancing / retreating the exposure head with respect to the photoconductor in a direction crossing a mounting / removal direction of the photoconductor unit with respect to the apparatus main body. The image forming apparatus according to 2. A cover for opening and closing the detachable opening;
A power transmission mechanism coupled to the cover and the advance / retreat mechanism, and transmitting power for retracting the exposure head from the photoreceptor to the advance / retreat mechanism in conjunction with opening of the cover; The image forming apparatus according to claim 3. The advancing / retreating mechanism includes a fixed shaft whose axis is fixed to the apparatus main body, a first arm whose one end is rotatably supported around the axis of the fixed shaft, and an axis line relative to the apparatus main body. A movable axis, one end holding the exposure head, and the other end connected to the one end of the first arm via the movable axis, with the axis of the moving axis as the center A second arm provided to be swingable,
5. The image forming apparatus according to claim 3, wherein the one end portion of the second arm is directed in a separation direction away from the attachment / detachment opening in a state where the exposure unit is in the retracted posture. .   6. The image forming apparatus according to claim 5, wherein the moving axis is moved in a direction opposite to the separation direction when the exposure unit is displaced from the exposure posture to the retracted posture. . The apparatus main body is provided with an arcuate guide portion for guiding the advance and retreat of the exposure head,
The photoconductor unit includes a developing device for supplying a developer to the photoconductor,
The image forming apparatus according to claim 3, wherein the developing unit has an outer shape that avoids a movement path of the exposure head guided by the guide unit.   The image forming apparatus according to claim 5, further comprising a biasing member that biases the exposure head toward the photosensitive member.   The image forming apparatus according to claim 8, wherein the urging member is interposed between the first arm and the second arm. The other end of the second arm is supported so as to be swingable with respect to the moving shaft,
The image forming apparatus according to claim 9, wherein the biasing member is interposed between the moving shaft and the second arm. A first gear that rotates integrally with the fixed shaft;
Gear teeth are partly on the circumference, and the gear teeth mesh with the first gear to transmit power for moving the exposure head forward and backward to the first gear. A second gear that disengages the gear teeth with respect to the first gear in a state closest to the photoreceptor.
The image forming apparatus according to claim 9, wherein the urging member is interposed between the apparatus main body and the first arm.

Images