JP5585321B2 - Image forming apparatus - Google Patents

Description

  The present invention relates to an image forming apparatus such as a copying machine, a facsimile machine, or a printer that forms an image by forming an electrostatic latent image on an image carrier using an optical writing device.

  An optical writing head (LED head) in which light emitting elements and rod lenses are arranged in the longitudinal direction of a photosensitive drum as an image carrier is held by an openable / closable cover that can be opened and closed with respect to the apparatus body, and optical writing is performed as the openable / closable cover opens and closes. 2. Description of the Related Art An electrophotographic color image forming apparatus is known that includes a moving unit that makes a head come into contact with and retreats from a positioning unit provided in the vicinity of a photosensitive drum.

  In the above-described image forming apparatus, since the plurality of optical writing heads are moved as the opening / closing cover is opened / closed, the movement trajectory of the optical writing head depends on the distance from the opening / closing fulcrum of the opening / closing cover. In the direct transfer method that directly transfers the image to the paper, the fixing device etc. is arranged on the rear side of the main body, so the opening / closing fulcrum of the opening / closing cover can be arranged at a position far from the optical writing head. In the intermediate transfer system that batch-transfers the paper onto the paper later, the depth of the apparatus main body is small, and the opening / closing fulcrum of the opening / closing cover cannot be moved far from the optical writing head. Therefore, the radius of curvature in the movement locus of the optical writing head arranged at a position close to the opening / closing fulcrum of the opening / closing cover is reduced, and the optical writing head comes into contact with the process unit and breaks when contacting or retracting. There was a problem.

  Therefore, in an image forming apparatus configured to hold the LED head by the opening / closing cover, when performing maintenance work such as releasing the paper jam or taking out the photosensitive unit by opening the opening / closing cover, a process is applied to the LED head protruding from the opening / closing cover. A technique for rotating the LED head to the retracted position after the opening / closing cover is opened to a predetermined angle by a driving means arranged near the rotation fulcrum of the opening / closing cover so that the unit does not contact is disclosed in, for example, “Patent Document 1”. It is disclosed.

  However, the above-described technique also has a problem that the distance between the opening / closing cover and the LED head has to be increased in order to prevent the LED head from coming into contact with the process unit, resulting in a large apparatus.

  The present invention solves the above-mentioned problems, and the optical writing head can be retracted from the process unit when the opening / closing cover is opened with a simple configuration without depending on the distance between the pivot point of the opening / closing cover and the optical writing head. An object of the present invention is to provide an image forming apparatus.

According to the first aspect of the present invention, there is provided an apparatus main body, a cover that is supported by the apparatus main body so as to be openable and closable on a rotation shaft, a process unit having an image carrier disposed in the apparatus main body, and the image carrier. An optical writing head for writing an electrostatic latent image on the image forming apparatus, wherein the optical writing head is supported by the cover and is capable of approaching and retracting from the process unit when the cover is opened and closed. The writing head has an engaging portion that engages with an engaged portion arranged in the process unit so as to determine a relative position with the image carrier when approaching the process unit, and the cover is in a closed position. When the optical writing head is released from the engaged portion, the optical writing head performs a retracting operation from the process unit after performing the disengaging operation of the engaging portion from the engaged portion, Serial saving operation and Ri moving track Do different of the optical write head associated with the opening operation of the cover at a head holding member for holding the optical write head, a connecting member supporting the head holding member rotatably, Holding member having a guide member that supports one end of the connecting member so as to move up and down, and an opening that rotatably supports one end of the connecting member at the other end and slidably supports the other end of the connecting member. The optical writing head linearly moves upward when the connecting member moves upward along the guide member during the detaching operation, and upwards during the retracting operation. The optical writing head is moved in a curved manner by rotating the connecting member upward with the moved end as a fulcrum .

  According to a second aspect of the present invention, in the image forming apparatus according to the first aspect, the rotating shaft is further provided in the same direction as the paper width direction.

According to a third aspect of the present invention, in the image forming apparatus according to the first or second aspect, the head holding member, the connecting member, and the connecting member holding member are provided in pairs, and each pair of the head holding members and The connection member and the connection member holding member are arranged on both outer sides in the rotation axis direction of the process unit .

According to a fourth aspect of the present invention, in the image forming apparatus according to the first or second aspect , the head holding member and the connecting member are provided in pairs, and a second connecting member that connects the other ends of the connecting members is provided. Each pair of the head holding member and the connecting member is arranged on both outer sides in the rotational axis direction of the process unit, and the connecting member holding member slidably supports the second connecting member by the opening. characterized in that it.

According to a fifth aspect of the present invention, in the image forming apparatus according to any one of the first to fourth aspects, when the cover is further opened by a predetermined angle, the connecting member or the second member is provided at the end of the opening. The opening operation of the cover is restricted by contact of the connecting member .

According to a sixth aspect of the present invention, in the image forming apparatus according to the fifth aspect , the opening further includes a locking portion that locks the connecting member or the second connecting member at the end, and the locking portion. When the connecting member or the second connecting member is locked, the open state of the cover is maintained .

According to a seventh aspect of the present invention, in the image forming apparatus according to the sixth aspect , the locking portion further includes a small-diameter portion having a smaller diameter than the supported portion in which the connecting member or the second connecting member is supported by the opening. becomes, the to the small-diameter portion the supported portion is the connecting member and the second coupling member, characterized in that it is locking by fitting.

According to an eighth aspect of the present invention, in the image forming apparatus according to the seventh aspect, the engaging portion is a fitting portion into which a supported portion in which the connecting member or the second connecting member is supported by the opening is fitted. have the supported portion in the fitting portion is the connecting member and the second coupling member, characterized in that it is locking by fitting.

According to a ninth aspect of the present invention, in the image forming apparatus according to any one of the first to eighth aspects, the image forming apparatus further includes a plurality of the image carrier and the optical writing head, and each of the optical writing heads corresponds to each of the optical writing heads. A plurality of the head holding members are provided.

A tenth aspect of the present invention is the image forming apparatus according to any one of the first to eighth aspects, further comprising a plurality of the image carrier and the optical writing head, wherein the light closest to the rotation axis. The writing head is held by the head holding member .

The invention of claim 11, wherein, in the image forming apparatus according to any one of claims 1 to 10, further wherein the optical write head, characterized in that a light emitting diode.

The invention of claim 12, wherein, in the image forming apparatus according to any one of claims 1 to 10, further wherein the optical write head, characterized in that an organic EL element.

According to a thirteenth aspect of the present invention, in the image forming apparatus according to any one of the first to twelfth aspects, the image forming apparatus further includes a fixing device , and the fixing device is provided between the optical writing head and the rotating shaft. Are not arranged .

  According to the present invention, the optical writing head that moves as the cover is opened continuously performs the disengaging operation of the engaging portion from the engaged portion and the retracting operation from the process unit, and the optical writing head is moved. During the detachment operation, the retraction operation is performed upward while drawing an arc, and the movement path of the optical writing head is different between the separation operation and the retraction operation, so that the rotation axis and the optical writing head The optical writing head can be withdrawn without interfering with the process unit and the optical writing head can be removed without depending on the distance between the optical writing head and the engaged portion with respect to the engaged portion. With a simple configuration, the retracting operation of the optical writing head from the process unit accompanying the opening operation of the cover can be performed.

1 is a schematic side view of an image forming apparatus employing a first embodiment of the present invention. It is the schematic of the process unit used for one Embodiment of this invention. FIG. 10 is a schematic diagram illustrating a retracting operation of an optical writing head accompanying a cover opening / closing operation in a conventional image forming apparatus. FIG. 10 is a schematic diagram illustrating a retracting operation of an optical writing head accompanying a cover opening / closing operation in a conventional image forming apparatus. It is the schematic explaining the positioning mechanism of the optical writing apparatus with respect to the process unit used for the 1st Embodiment of this invention. 1 is a schematic front view of an image forming apparatus employing a first embodiment of the present invention. FIG. 6 is a schematic front view of an image forming apparatus adopting a modification of the first embodiment of the present invention. It is the schematic explaining the cover opening operation | movement in the 1st Embodiment of this invention. It is the schematic explaining the movement of the optical writing head accompanying the cover opening operation | movement in the 1st Embodiment of this invention. It is the schematic explaining the movement of the optical writing head accompanying the cover opening operation | movement in the 1st Embodiment of this invention. It is the schematic explaining the movement of the optical writing head accompanying the cover opening operation | movement in the 1st Embodiment of this invention. It is the schematic explaining the connection bar holding member used for the 2nd Embodiment of this invention. It is the schematic explaining the connection bar holding member used for the 2nd Embodiment of this invention. It is the schematic explaining the connection bar holding member used for the 3rd Embodiment of this invention.

  FIG. 1 is a schematic diagram of a color printer 1 as an image forming apparatus employing an embodiment of the present invention. In the figure, the right side shows the front side of the printer 1 and the left side shows the rear side of the printer 1. The printer 1 includes four process units 2Y, 2M, 2C, and 2K for forming yellow (Y), magenta (M), cyan (C), and black (K) toner images. The units 2Y, 2M, 2C, and 2K are the same except that toners of different colors (Y: yellow, M: red, C: blue, K: black) are used, and are replaced when the lifetime is reached.

  FIG. 2 shows a process unit 2K for forming a black toner image. The process unit 2K includes a photosensitive drum 3K as an image carrier, a drum cleaning device 4K, a neutralizing device (not shown), a charging device 5K, a developing device 6K, and the like, and is detachable from the apparatus main body of the printer 1. Consumables can be replaced at a time.

  The charging device 5K uniformly charges the surface of the photosensitive drum 3K that is driven to rotate clockwise in FIG. 2 by a driving unit (not shown), and the charged surface of the photosensitive drum 3K is exposed by the optical writing head 7K. Thus, an electrostatic latent image for black is formed. The formed electrostatic latent image is visualized by black toner stored in the developing device 6K, and the drum cleaning device 4K removes the transfer residual toner adhering to the surface of the photosensitive drum 3K after the transfer process. A neutralization device (not shown) neutralizes the residual potential of the photosensitive drum 3K after cleaning, and the surface of the photosensitive drum 3K is initialized by this neutralization to prepare for the next image formation.

  The developing device 6K includes a vertically long hopper portion 8K that stores black toner (not shown) and a developing portion 9K. In the hopper 8K, an agitator 10K that is rotationally driven by a driving means (not shown), an agitation paddle 11K that is arranged below the agitator 10K and is rotationally driven by a driving means (not shown), and an arrangement that is arranged below the agitation paddle 11K. A toner supply roller 12K that is rotationally driven by a driving means that does not operate is provided. The black toner in the hopper 8K moves toward the toner supply roller 12K by its own weight while being stirred by the rotation of the agitator 10K and the stirring paddle 11K. The toner supply roller 12K has a metal cored bar and a roller portion made of foamed resin or the like coated on the surface thereof, and rotates while adhering black toner in the hopper portion 8K to the surface of the roller portion. .

  In the developing unit 9K, a developing roller 13K that rotates while contacting the photosensitive drum 3K and the toner supply roller 12K, a thinning blade 14K that has a tip abutting the surface of the developing roller 13K, and the like are disposed. . The black toner adhering to the toner supply roller 12K is supplied to the surface of the developing roller 13K at the contact portion with the developing roller 13K, and passes through the contact position with the thinning blade 14K as the developing roller 13K rotates. Layer thickness is regulated. The black toner after the regulation of the layer thickness adheres to the electrostatic latent image formed on the photosensitive drum 3K in the developing area where the developing roller 13K and the photosensitive drum 3K are in contact with each other. The image is visualized with black toner. Similarly, in the other process units 2Y, 2M, and 2C, a yellow toner image, a red toner image, and a blue toner image are formed on the photosensitive drums 3Y, 3M, and 3C, respectively, and the formed color toner images are transferred belts to be described later. And transferred to the paper P.

  Optical writing heads 7Y, 7M, 7C, and 7K are disposed near the upper portions of the photosensitive drums 3Y, 3M, 3C, and 3K. Each optical writing head 7 exposes each photosensitive drum 3 by causing a light emitting element at a predetermined position to emit light based on image information, and the surface of each photosensitive drum 3 is for yellow, red, blue, and black. Each electrostatic latent image is formed. Each optical writing head 7 arranges light emitting elements such as light emitting diodes (LEDs) in the longitudinal direction of the respective photosensitive drums 3, and similarly, each rod through the rod lenses arranged in the longitudinal direction of the respective photosensitive drums 3. The photosensitive drum 3 is irradiated. As each optical writing head 7, an organic EL element may be used instead of the LED.

  Below each process unit 2 is an endless intermediate transfer belt 16, a drive roller 17, a driven roller 18, four primary transfer rollers 19Y, 19M, 19C, and 19K, a secondary transfer roller 20, and a belt. A transfer unit 15 having a cleaning device 21 and the like is disposed. The intermediate transfer belt 16 is stretched by rollers 17, 18, and 19, and is driven to run counterclockwise in FIG. 1 when the drive roller 17 is rotationally driven by a driving unit (not shown). Each primary transfer roller 19 is in contact with a corresponding photosensitive drum 3 via an intermediate transfer belt 16, and a primary transfer nip portion is provided at a portion where the intermediate transfer belt 16 and each photosensitive drum 3 are in contact with each other. Is formed. A primary transfer bias is applied to each primary transfer roller 19 from a power source (not shown), whereby a transfer electric field is formed between the toner image on each photosensitive drum 3 and each primary transfer roller 19. Instead of each primary transfer roller 19, a transfer charger or a transfer brush may be used.

  When the yellow toner image formed on the surface of the photosensitive drum 3Y enters the primary transfer nip portion as the photosensitive drum 3Y rotates, the yellow toner image is transferred from the photosensitive drum 3Y to the intermediate transfer belt by an action such as a transfer electric field and nip pressure. First transfer to 16. The intermediate transfer belt 16 on which the yellow toner image is primarily transferred is sequentially superposed with the toner images of the respective colors when passing through the primary transfer nip portions for red, blue, and black as the traveling movement thereof. As a result, a four-color toner image is formed on the intermediate transfer belt 16.

  The secondary transfer roller 20 is disposed at a position where the secondary transfer roller 20 is in contact with the driving roller 17 via the intermediate transfer belt 16, and a secondary transfer nip portion is formed at a portion where the intermediate transfer belt 16 and the secondary transfer roller 20 are in contact. Has been. A secondary transfer bias is applied to the secondary transfer roller 20 from a power source (not shown), whereby a secondary transfer electric field is formed between the secondary transfer roller 20 and the drive roller 17 connected to the ground.

  Below the transfer unit 15, there is disposed a paper feed cassette 22 that stores a plurality of recording papers P in a bundle of sheets, and the paper feed cassette 22 is slidable with respect to the main body of the printer 1. It is configured. The recording paper P is fed toward the post-feed conveyance path 23 by rotating counterclockwise in FIG. 1 at a position where it abuts on the uppermost recording paper P of the paper bundle accommodated in the paper feeding cassette 22. A sheet feeding roller 24 is disposed, and a registration roller pair 25 is disposed in the vicinity of the end of the conveyance path 23 after sheet feeding. The registration roller pair 25 stops when the recording paper P fed from the paper feed cassette 22 is sandwiched between the rollers, and rotates at a timing at which the recording paper P synchronizes with the four-color toner image formed on the intermediate transfer belt 16. Then, the recording paper P is fed toward the secondary transfer nip portion.

  The four-color toner images on the intermediate transfer belt 16 that are in close contact with the recording paper P in the secondary transfer nip portion are subjected to secondary transfer collectively onto the recording paper P under the influence of the secondary transfer electric field and nip pressure, A full color toner image is transferred onto the recording paper P. The recording paper P having the full-color toner image transferred to the surface is separated from the secondary transfer roller 20 and the intermediate transfer belt 16 by the curvature after passing through the secondary transfer nip portion, and then the fixing device 27 via the post-transfer conveyance path 26. Sent to. Transfer residual toner that has not been transferred to the recording paper P adheres to the intermediate transfer belt 16 that has passed through the secondary transfer nip, and this transfer residual toner is cleaned by the belt cleaning device 21.

  The fixing device 27 includes a fixing roller 28 including a heat source such as a halogen lamp (not shown), and a pressure roller 29 that rotates while being pressed against the fixing roller 28 with a predetermined pressure. The fixing nip portion is formed at the portion. The recording paper P fed into the fixing device 27 is sandwiched between the fixing nip portion in such a manner that the unfixed toner image carrying surface is brought into close contact with the fixing roller 28, and the toner is softened by the influence of heating and pressurization, so that a full color image is obtained. Is fixed to the recording paper P. The recording paper P discharged from the fixing device 27 is discharged out of the apparatus by a pair of paper discharge rollers 32 through a post-fixing conveyance path 30 and a paper discharge path 31, and can be opened and closed with respect to the apparatus main body at the top of the apparatus main body. It is stacked on the stack portion provided on the upper surface of the provided cover 33.

  In the printer 1 having the above-described configuration, when the process unit 2 that is a consumable is replaced, the optical writing head 7 disposed in the vicinity of the photosensitive drum 3 is in the way and the process unit 2 cannot be removed from the apparatus main body. Therefore, a configuration is known in which the optical writing head 7 is held by a cover 33 that is openable and closable with respect to the apparatus main body, and the optical writing head 7 is retracted by opening the cover 33 during replacement work. In the present embodiment, the cover 33 is supported on the main body of the apparatus by a rotating shaft 34 extending in the width direction of the recording paper P, and each optical writing head 7 has a head holder 35 as a head holding member. And is held by the cover 33. The holding mechanism for each optical writing head 7 will be described later.

Here, a configuration of a conventional example in which the writing head is retracted by opening the cover when the process unit 2 is replaced will be described.
In the conventional printer 50 shown in FIG. 3, the same components as those of the printer 1 described above are denoted by the same reference numerals, and detailed descriptions thereof are omitted. This printer 50 is a so-called direct transfer system in which the toner images formed in each process unit 2 are sequentially transferred onto the recording paper P by the transfer unit 51 and a full color image is formed on the recording paper P. Each optical writing head 7 is held by a head holder 35, and each head holder 35 is fixed to a cover 33. After the transfer operation in the transfer unit 51, the recording paper P onto which the toner image has been transferred is fixed on the toner image by the fixing device 27, and then discharged to the outside by the paper discharge roller pair 32 and provided on the upper surface of the cover 33. Stacked in the stack.

  The cover 33 can be opened upward with the pivot shaft 34 as a fulcrum. In this conventional example, each optical writing head 7 also moves integrally with the cover 33 along the locus of the arrow in the figure, and the cover 33 and each optical writing The head 7 is in a state indicated by a broken line when opened. In the configuration of the printer 50, the fixing device 27 is disposed between the optical writing head 7 and the rotating shaft 34, and the rotating shaft 34 can be disposed at a position far from the optical writing head 7. When the cover 33 is opened, each optical writing head 7 can move to the retracted position (the position where the cover 33 occupies the open position) without interfering with each process unit 2.

  FIG. 4 shows a conventional printer 52 having a different configuration, and the same reference numerals are given to the same configuration as the printer 1 described above, and detailed description thereof is omitted. The printer 52 is configured in the same manner as the printer 1 except for the holding mechanism of the optical writing head 7. Each optical writing head 7 is held by a head holder 35, and each head holder 35 is interposed via a rotating member 53. The cover 33 is rotatably supported. When the cover 33 is opened, each optical writing head 7 is rotated about the rotating member 53 as a fulcrum when the cover 33 is opened, so that the head holder 35 is maintained in the vertical direction and is moved to the retracted position. And move.

  In the printer 52 having the above-described configuration, each optical writing head 7 can be retracted without interfering with each process unit 2 by opening the cover 33. However, each optical writing head 7 needs to be positioned with respect to each corresponding photosensitive drum 3, and as shown in FIG. 5, the optical writing head 7 has a positioning hole 7 a which is an engaging portion, as shown in FIG. A positioning projection 2b, which is an engaged portion, is provided on the case 2a that constitutes the above. Unlike the printer 52 shown in FIG. 4 or the printer 1 shown in FIG. 1, the fixing device 27 is not disposed between the optical writing head 7 and the rotating shaft 34, and the cover 33 is opened. Among the optical writing heads 7 that perform the retracting operation, when the radius of curvature of the movement locus is small, such as the optical writing head 7K or the optical writing head 7C, the positioning hole 7a contacts the positioning protrusion 2b obliquely from above. As a result, the positioning hole 7a cannot be fitted into the positioning projection 2b, and there is a possibility that accurate positioning is not performed. In such a situation, the relative position between the photosensitive drum 3 and the optical writing head 7 shifts, and an electrostatic latent image is not written at a predetermined position on the photosensitive drum 3. There is a problem that when the image is primarily transferred from the drum 3, a positional shift occurs and an image defect occurs. Further, even when the cover 33 is opened from the state in which the cover 33 is closed and the positioning hole 7a is fitted to the positioning projection 2b, the optical writing heads 7 are fitted when they try to move obliquely upward. There is a possibility that the portion may be twisted or the positioning projection 2b may be damaged. This also causes an image defect as described above.

  A configuration in which the positioning hole 7a can be reliably engaged (fitted) / detached with respect to the positioning projection 2b while preventing the occurrence of the above-described image defect will be described below as a first embodiment of the present invention. In FIG. 1, each optical writing head 7 is held at one end of a head holder 35 and is urged toward the photosensitive drum 3 by urging means (not shown). The other end of each head holder 35 is rotatably supported by a connecting bar 37 as a connecting member via a rotating member 36. One end of the connection bar 37 is supported by a guide member 38 disposed in the apparatus main body so as to be movable up and down, and the other end is rotated around the cover 33 by a rotation member 39 via a rotation member 36. It is slidably supported by an opening 40a formed at the other end of the connecting bar holding member 40, which is a connecting member holding member that is movably connected. One end of the connecting bar 37 is urged vertically upward by an urging means (not shown), and is locked by a locking mechanism (not shown) so that the urging force of the urging means does not act on one end of the linking bar 37. A lock mechanism (not shown) is automatically released as the cover 33 is opened. The guide member 38 includes a linear portion 38 a that guides one end of the connecting bar 37 in the vertical direction, and an arc portion 38 b that rotatably supports one end of the connecting bar 37.

  FIG. 6 is a view of the printer 1 as viewed from the front. A left frame 42 is disposed inside the left side wall 41 of the apparatus main body, and a right frame 44 is disposed inside the right side wall 43. The head holder 35 has a substantially U shape having a pair of leg portions, and the leg portions are rotatably supported by the pair of connecting bars 37 while holding the optical writing head 7. Each connecting bar 37 is disposed inside each leg portion of the head holder 35, and a pair of connecting bar holding members 40 are respectively disposed outside each leg portion of the head holder 35. The leg portions of the head holder 35, the connecting bars 37, and the connecting bar holding members 40 are disposed between the process units 2 and the frames 42 and 44, respectively, and the optical writing heads 7 are retracted. It is configured not to interfere with each process unit 2 when moving to a position. The arrangement order of the leg portions of the head holder 35, the connection bars 37, and the connection bar holding members 40 is not limited to this, and is arranged at a position between the process units 2 and the frames 42 and 44. Any order is acceptable. Further, as shown in FIG. 7, a connection member 45 as a second connection member that connects the other ends of the connection bars 37 is provided, and the connection bar holding member is configured to support the substantially central portion of the connection member 45 by the opening 40 a. A configuration may be adopted in which only one 40 is provided.

  The retracting operation of each optical writing head 7 accompanying the opening operation of the cover 33 in the printer 1 will be described. When the cover 33 is opened upward from the state shown in FIG. 1, the opening 40a slides with respect to the other end of the connecting bar 37 up to the position shown in FIG. At the same time, the connecting bar 37, each head holder 35 and each optical writing head 7 do not move.

  When the cover 33 is further opened from the state shown in FIG. 8, the other end of the connecting bar 37 comes into contact with the end surface of the opening 40a as shown in FIG. 9, and moves upward as the connecting bar holding member 40 moves upward. The one end moves upward along the straight portion 38a by releasing a lock mechanism (not shown). By this operation, the positioning hole 7a is satisfactorily detached without being twisted from the positioning projection 2b, and the separation operation of each optical writing head 7 is completed by this series of operations.

  When the cover 33 is further opened from the state shown in FIG. 9, the other end of the connecting bar 37 is lifted further upward by the connecting bar holding member 40 as shown in FIG. 10, and one end climbs up the straight portion 38a. The arc reaches the arc portion 38b, and the connecting bar 37 rotates with the arc portion 38b as a fulcrum. When the cover 33 is finally opened to the position shown in FIG. 11, the cover 33 is held in an opened state by a holding member (not shown) provided in the vicinity of the rotation shaft 34. The retracting operation of the optical writing head 7 is completed. Further, by performing the above operations in reverse, the proximity operation and the positioning operation of each optical writing head 7 with respect to each process unit 2 are performed in accordance with the closing operation of the cover 33.

  In the opening operation of the cover 33 described above, each optical writing head 7 that moves as the cover 33 is opened continuously performs the detaching operation of the positioning hole 7a from the positioning projection 2b and the retracting operation from the process unit 2, and The movement of each optical writing head 7 is performed upward while drawing a circular arc during the retreating operation in the vertically upward direction during the detaching operation, and the movement locus of each optical writing head 7 is different between the separating operation and the retreating operation. Thus, each optical writing head 7 can be detached without depending on the distance between the rotation shaft 34 and each optical writing head 7 and without squeezing the positioning hole 7a with respect to the positioning projection 2b. Each optical writing head 7 can be retracted without interfering with 2 and the cover 33 can be opened with a simple configuration. It is possible to perform the save operation from the process unit 2 of each optical writing head 7.

  FIG. 12 shows a second embodiment of the present invention. This second embodiment differs from the first embodiment described above only in that a connection bar holding member 46, which is a connection member holding member, is used in place of the connection bar holding member 40. Are the same. The connecting bar holding member 46 has an opening 46a that slidably supports the rotating member 36 or the connecting member 45 provided at the other end of the connecting bar 37 that is a supported portion, and below the opening 46a. A small-diameter portion 46 b formed by an elastic member and having a smaller diameter than the rotating member 36 or the connecting member 45 is provided at the side end portion. With this configuration, when the cover 33 is opened from the state shown in FIG. 8 to the state shown in FIG. 10, the rotating member 36 or the connecting member 45 is positioned in front of the small diameter portion 46b as shown in FIG. When the cover 33 is in the fully opened state shown in FIG. 11, the rotating member 36 or the connecting member 45 is fitted into the small diameter portion 46b as shown in FIG. 13, and the cover 33 is opened. Can be maintained. Thereby, the holding member (not shown) described above can be omitted.

  FIG. 14 shows a connecting bar holding member 47 as a connecting member holding member used in the third embodiment of the present invention. The connecting bar holding member 47 has an opening 47a that slidably supports the rotating member 36 or the connecting member 45, and is formed of an elastic member near the lower end of the opening 47a. Protrusions 47 b are formed so that the width L is smaller than the rotation member 36 or the connection member 45. With this configuration, when the cover 33 is opened from the state shown in FIG. 8 to the state shown in FIG. 10, the rotating member 36 or the connecting member 45 occupies a state positioned in front of the protruding portion 47b. When the cover 33 is in the fully opened state shown in FIG. 11, the rotating member 36 or the connecting member 45 gets over the protruding portion 47b and fits into the fitting portion 47c formed below the protruding portion 47b. 33 can maintain an open state. Thereby, the holding member (not shown) described above can be omitted.

  In each of the above-described embodiments, a plurality of optical writing heads 7 are provided, and the movement trajectories are different for all optical writing heads 7 during the detaching operation and during the retracting operation. However, as shown in FIG. If the distance between the shaft 34 and the optical writing head 7 can be sufficiently set, it is not necessary to apply the above-described configuration to all the optical writing heads, and at least the optical writing head 7 closest to the rotating shaft 34 is described above. The configuration described above may be applied.

  In the above embodiment, an example in which a color printer is used as an image forming apparatus has been described. However, an image forming apparatus to which the present invention can be applied is not limited to this, and a copier, a plotter, a facsimile, a printing machine, a complex machine of these, or the like The present invention can also be applied to other image forming apparatuses.

1 Image forming device (copier)
2 Process unit 2b Engagement part (positioning protrusion)
3 Image carrier (photosensitive drum)
7 Optical writing head 7a Engagement part (positioning hole)
27 Fixing device 33 Cover 34 Rotating shaft 35 Head holding member (head holder)
37 Connection member (connection bar)
38 Guide members 40, 46, 47 Connecting member holding member (connecting bar holding member)
45 Second connecting member (connecting member)
46b Small diameter part 47c Fitting part

JP 2007-65125 A

Claims (13)

An apparatus main body, a cover supported by the apparatus main body on the rotation shaft so as to be opened and closed, a process unit having an image carrier disposed in the apparatus main body, and light for writing an electrostatic latent image on the image carrier In the image forming apparatus, the optical writing head is supported by the cover and can be moved close to and retracted from the process unit in accordance with the opening and closing operation of the cover.
The optical writing head has an engaging portion that engages with an engaged portion disposed in the process unit to determine a relative position with the image carrier when approaching the process unit, and the cover includes When the optical writing head is released from the closed position, the optical writing head performs a retracting operation from the process unit after performing the disengaging operation of the engaging portion from the engaged portion. Ri moving track Do different of the optical write head associated with the opening operation of the cover, a head holding member for holding the optical write head, a connecting member supporting the head holding member rotatably, one end of said connecting member And a connecting member holding member having one end rotatably supported by the cover and an opening at the other end slidably supporting the other end of the connecting member. The optical writing head linearly moves upward when the connecting member moves upward along the guide member during the detaching operation, and upwards during the retracting operation. An image forming apparatus, wherein the optical writing head is moved in a curved manner by rotating the connecting member upward with the moved end as a fulcrum . The image forming apparatus according to claim 1.
The image forming apparatus, wherein the rotation shaft is provided in the same direction as the paper width direction. The image forming apparatus according to claim 1 or 2,
Each of the head holding member, the connecting member, and the connecting member holding member is provided in pairs, and each of the pair of the head holding member, the connecting member, and the connecting member holding member is on both outer sides in the rotation axis direction of the process unit. the image forming apparatus characterized by being arranged to. The image forming apparatus according to claim 1 or 2 ,
Each of the head holding member and the connecting member is provided in a pair, and has a second connecting member that connects the other end of each connecting member, and each pair of the head holding member and the connecting member rotates the process unit. An image forming apparatus, wherein the image forming apparatus is disposed on both outer sides in the axial direction, and the connection member holding member slidably supports the second connection member by the opening . The image forming apparatus according to any one of claims 1 to 4 ,
2. An image forming apparatus according to claim 1, wherein when the cover is opened at a predetermined angle, the opening operation of the cover is restricted by contact of the connecting member or the second connecting member with an end of the opening . The image forming apparatus according to claim 5 .
The opening has a locking portion for locking the connecting member or the second connecting member at the end portion, and the connecting member or the second connecting member is locked to the locking portion, thereby An image forming apparatus, wherein an open state is maintained . The image forming apparatus according to claim 6 .
The locking portion includes a small-diameter portion having a smaller diameter than the supported portion where the connecting member or the second connecting member is supported by the opening, and the supported member is fitted into the small-diameter portion, thereby the connecting member. or the image forming apparatus in which the second coupling member, characterized in that it is engaging. The image forming apparatus according to claim 7.
The locking portion has a fitting portion into which a supported portion in which the connecting member or the second connecting member is supported by the opening is fitted, and the supported portion is fitted into the fitting portion. image forming apparatus, characterized in that the connecting member or the second coupling member is engaging. The image forming apparatus according to any one of claims 1 to 8 ,
An image forming apparatus comprising a plurality of the image carrier and the optical writing head, and a plurality of the head holding members corresponding to the optical writing heads . The image forming apparatus according to any one of claims 1 to 8 ,
An image forming apparatus comprising a plurality of the image carrier and the optical writing head, wherein the optical writing head closest to the rotation axis is held by the head holding member . The image forming apparatus according to any one of claims 1 to 10,
An image forming apparatus, wherein the optical writing head is a light emitting diode . The image forming apparatus according to any one of claims 1 to 10,
An image forming apparatus, wherein the optical writing head is an organic EL element . The image forming apparatus according to any one of claims 1 to 12,
An image forming apparatus comprising a fixing device, wherein the fixing device is not disposed between the optical writing head and the rotation shaft .

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