JP7199915B2 - image forming device - Google Patents

Description

The present invention relates to an electrophotographic image forming apparatus such as a digital copier and a facsimile machine.

2. Description of the Related Art Conventionally, as a technique related to an exposure device used in an electrophotographic image forming apparatus, for example, the technique described in Japanese Patent Application Laid-Open No. 2002-200001 is known. Japanese Patent Application Laid-Open No. 2002-200002 describes an LED array type exposure device in which a plurality of light emitting points are arranged in the vicinity of the surface of a photoreceptor along the axial direction of the photoreceptor to form a latent image on the surface of the photoreceptor. Further, Japanese Patent Application Laid-Open No. 2002-200002 proposes a folding advance/retreat mechanism in order to reduce the space for retracting the exposure device from the photoreceptor.

In the exposure apparatus disclosed in Japanese Patent Application Laid-Open No. 2002-200000, the retraction mechanism for the exposure member is folded using a plurality of arms, thereby reducing the space required for retraction and realizing the miniaturization of the main body of the image forming apparatus. However, in the case of an exposure apparatus using such a configuration, there is a problem that when dust adheres to the LED head, which is an exposure member, it is difficult to remove the dust. When an LED head is used as the exposure member, unlike the laser scanner system using a rotating polygon mirror, the LED head must be arranged very close to the photosensitive drum, which is the surface to be scanned. In that case, the distance between the surface of the lens array of the LED head and the surface of the photosensitive drum is generally about 3 mm. Therefore, if print output is continued for a certain period of time, toner and its external additives that scatter near the photosensitive drum adhere to the lens array surface of the LED head, resulting in white streaks and density unevenness in the image printed on the recording material. image defects may occur. Therefore, a user or a maintenance person needs to periodically clean the surface of the lens array to remove dirt such as toner adhered to the lens array surface.

In the exposure apparatus having the above-described configuration, when dirt adheres to the surface of the lens array, first open the front cover for maintenance work of the image forming apparatus, pull out the drum unit housing the photosensitive drum from the attachment/detachment opening, and remove it from the image forming apparatus. Leave it removed. At that time, the LED head moves to a position retracted from the photosensitive drum in conjunction with the opening operation of the front cover. Next, a hand is inserted through the attachment/detachment opening, and dirt such as toner adhering to the surface of the lens array is wiped off using a cleaning member.

JP 2010-271743 A

In the configuration of the conventional example described above, the height of the lens array of the LED head retracted from the photosensitive drum is the same among the plurality of image forming stations, and they are arranged in a straight line at the same height. Therefore, when cleaning the lens array of the LED head of the image forming station installed on the back side in the direction away from the front cover, the lens array of the LED head of the image forming station installed in front of it becomes an obstacle. As described above, the visibility of the lens array to be cleaned is low, and moreover, it is difficult to reliably remove dirt from the surface of the lens array because it may be accidentally touched and soiled during cleaning work. There is a problem.

SUMMARY OF THE INVENTION It is an object of the present invention to improve workability when cleaning the lens surface of an exposure head.

In order to solve the above problems, the present invention has the following configuration.

(1) An image forming apparatus having an opening formed in a side surface of an apparatus main body and having a housing that is movable between a position attached to the apparatus main body and a position pulled out from the apparatus main body through the opening. a plurality of photosensitive drums provided in parallel along the direction of movement of the housing and rotatable with respect to the housing; and an exposure position provided in the apparatus main body for exposing the photosensitive drums from above in the vertical direction. and a retracted position retracted vertically above the exposure position; a closed position provided rotatably with respect to the apparatus main body; a cover that is pivotally movable to and from an open position; and when the cover is positioned at the closed position, the plurality of optical print heads are positioned at the exposure position, and the cover is positioned at the open position. a moving mechanism for moving the plurality of optical print heads in conjunction with the rotation of the cover so that the plurality of optical print heads are positioned at the retracted position; The optical printheads of are positioned lower in the vertical direction as the optical printheads are positioned farther from the opening in the direction of movement of the housing , and both ends of the optical printheads in the longitudinal direction of the optical printheads. is formed with a projection extending in the longitudinal direction, and the device main body has a side plate formed with a groove in which the projection is fitted, at a position opposed to the optical print head in the longitudinal direction, the groove being arc-shaped. , wherein the curvature of the arc varies depending on the corresponding optical print head .

According to the present invention, it is possible to improve workability when cleaning the lens surface of the exposure head.

1 is a schematic cross-sectional view showing the configuration of an image forming apparatus of Example 1; FIG. 2 is a cross-sectional view showing the configuration around the image forming unit of Examples 1 and 2; 1 is a schematic cross-sectional view showing the configuration of an image forming apparatus of Example 1; FIG. 2 is a cross-sectional view showing the configuration of the image forming unit of Examples 1 and 2; 4 is a perspective view showing a cross section of the LED exposure head of Examples 1 and 2; FIG. FIG. 2 is a cross-sectional view showing the structure of the LED exposure head of Examples 1 and 2; 4 is a perspective view showing the shape of the LED exposure head of Examples 1 and 2; FIG. FIG. 2 is a schematic cross-sectional view showing the configuration of the image forming apparatus with the image forming unit removed according to the first embodiment; Schematic cross-sectional view showing the configuration of an image forming apparatus of Embodiment 2 Schematic cross-sectional view showing the configuration of an image forming apparatus of Embodiment 2 FIG. 2 is a schematic cross-sectional view showing the configuration of the image forming apparatus with the image forming unit removed according to the second embodiment;

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

[Configuration of Image Forming Apparatus]
FIG. 1 is a schematic cross-sectional view showing the configuration of an image forming apparatus 100 to which Embodiment 1 is applied. In the drawings, (front) indicates the front side (front side) of the image forming apparatus 100, and (rear) indicates the rear side (rear side) of the image forming apparatus 100. The same applies to other drawings. . In FIG. 1, an image forming unit 270 that forms an image on the recording material S is installed in the central portion inside the image forming apparatus 100 . The image forming unit 270, which is a housing, is a so-called tandem image forming unit having four developing cartridges 220 containing toner materials for color printing.

[Configuration of Image Forming Unit]
A configuration of the image forming section 270 will be described with reference to the drawings. FIG. 2 is a cross-sectional view of the image forming unit 270 and its peripheral devices extracted from FIG. 1 in order to explain the image forming unit 270. As shown in FIG. The image forming unit 270 shown in FIG. 2 is a so-called tandem system image forming station in which image forming stations for forming toner images of respective colors are arranged in the image forming apparatus 100 so as to face the transfer belt 260 that conveys the recording material S. Department. Image forming stations for forming toner images of four colors, that is, yellow (Y), magenta (M), cyan (C), and black (BK) are arranged from left to right in FIG. from upstream to downstream in the conveying direction). Note that the number of toner colors is not limited to four, and the arrangement order of the image forming stations is not limited to this. In addition, a, b, c, and d at the end of the reference numerals in the figure indicate members of yellow (Y), magenta (M), cyan (C), and black (BK) image forming stations, respectively. The same applies to other drawings. In the following, descriptions of a, b, c, and d at the end of the reference numerals are omitted except when indicating that they are members of a specific image forming station. Each color image forming station has a photosensitive drum 210 , a charger 212 , and a developer cartridge 220 . The photosensitive drum 210 rotates in the arrow direction (counterclockwise direction) in the drawing, and an electrostatic latent image is formed by the exposure unit 12, which will be described later. A charger 212 charges the surface of the photosensitive drum 210 to a uniform potential. The developer cartridge 220 has a developer sleeve 218 that stores toner therein and causes the toner to adhere to the photosensitive drum 210 .

The transfer belt 260 is an endless belt that is rotationally driven in the arrow direction (R1) in the drawing, and conveys a recording material S, which will be described later. The transfer belt 260 is stretched by rollers including an inner transfer roller 261 , a driven roller 262 and a tension roller 263 which are arranged at positions facing the respective photosensitive drums 210 . The inner transfer roller 261 also serves as a drive roller that drives the transfer belt 260 .

[Image forming process]
Next, an image forming process in which the image forming apparatus 100 forms an image on the recording material S will be described with reference to FIGS. 1 and 2. FIG. When image formation is started, each image station of the image forming section 270 starts forming a toner image of each color. Since the configuration of each image forming station is the same except for the color of the toner, the image forming station of one color will be described below. A similar image forming operation is performed for the image forming stations of other colors. When the image forming operation is started, first, the charger 212 charges the surface of the photosensitive drum 210 to a uniform potential. Next, an electrostatic latent image is formed on the surface of the photosensitive drum 210 by the exposure unit 12 that irradiates a light beam based on a signal of image information. The developing sleeve 218 attaches the toner stored in the developing cartridge 220 to the electrostatic latent image on the photosensitive drum 210 to perform development and form a toner image.

On the other hand, as shown in FIG. 1, the recording materials S are stored in the form of stacking in the paper cassette 4 . The recording material S is fed by a paper feeding roller 219 and conveyed to the image forming section 270 in accordance with the image forming timing of the image forming station. The recording material S is conveyed to the transfer portion T1 of the image forming portion 270 by the transfer belt 260 . A transfer portion T1 is a transfer nip portion formed by the photosensitive drum 210 and the transfer belt 260 . By applying a predetermined bias to the inner transfer roller 261 arranged at a position facing the photosensitive drum 210 and pressing the recording material S on the transfer belt 260 toward the photosensitive drum 210 , the photosensitive drum 210 is applied to the recording material S. Transfer the upper toner image. The toner images of each color processed in parallel by each image forming station are sequentially superimposed and transferred onto the recording material S on the transfer belt 260, and finally a full-color toner image is formed on the recording material S. FIG.

After that, the recording material S onto which the toner image has been transferred is conveyed to the fixing device 30 and is pressurized and heated by the fixing device 30 to melt and fix the toner image onto the recording material S. FIG. The recording material S on which the toner image is thus fixed is discharged onto the discharge tray 312 by the discharge roller 22 .

[Removal of Image Forming Unit]
As shown in FIG. 1, the image forming apparatus 100 has a cover 1 which is a door that can be opened and closed on the front side of the apparatus main body (the left side in FIG. 1 indicated by (front) in the figure). 2 is a schematic cross-sectional view of the image forming apparatus 100 with the cover 1 closed; FIG. On the other hand, FIG. 3 is a schematic cross-sectional view of the image forming apparatus 100 with the cover 1 opened from the closed state shown in FIG. In FIG. 3, when the cover 1 is opened, the attachment/detachment opening 2, which is an opening provided on the side surface of the image forming apparatus 100 for attaching/detaching the image forming unit 270, appears on the front side of the image forming apparatus 100. As shown in FIG.

As shown in FIG. 3, below the attachment/detachment opening 2 of the image forming apparatus 100, a cover shaft 3 is arranged as a central axis of rotation of the cover 1 when the cover 1 is opened and closed. The cover shaft 3 rotatably supports one end of an arm 5 connecting the cover 1 and the cover shaft 3 . The other end of the arm 5 integrally holds the cover 1 so that the cover 1 can rotate around the cover shaft 3 .

Further, as shown in FIG. 3, the above-described image forming section 270 is installed in the center of the inside of the image forming apparatus 100 on the rear side of the attachment/detachment opening 2 (on the right side in the drawing). In general, the developing cartridge 220 and the photosensitive drum 210 are consumables and have a shorter durability period (so-called service life) than other devices (for example, the fixing device 30) that constitute the image forming apparatus 100. , need to be replaced. Therefore, in the image forming apparatus 100, the image forming section 270 is detachable. That is, in the image forming apparatus 100, the image forming unit 270 can be removed by pulling the image forming unit 270 out of the attachment/detachment opening 2 in the direction of arrow G in the drawing while the cover 1 is open. On the other hand, by inserting the image forming section 270 in the direction opposite to the arrow G direction, the image forming section 270 can be moved to the mounting position where it is mounted on the image forming apparatus 100 (installed). In the image forming apparatus 100, a rail member (not shown) on which the image forming unit 270 is placed extends in the insertion direction of the image forming unit 270 in order to facilitate attachment and detachment of the image forming unit 270. there is The image forming unit 270 is placed on the rail member and is movable inside the image forming apparatus 100 by being guided by the rail member.

The image forming apparatus 100 also includes a pair of side plates 211 that sandwich the image forming section 270 from the left and right (the front-rear direction of the paper surface of FIGS. 1 and 3). The side plate 211 as a side wall is a metal sheet frame, and stays (not shown) bridging between the side plate 211 and the side plate 211 provided on the left and right sides of the image forming apparatus 100 ensure the rigidity of the frame.

FIG. 4 is a sectional view showing the configuration of the image forming section 270 extracted from the image forming apparatus 100. As shown in FIG. For example, when replacing the developing cartridge 220 , the image forming section 270 is pulled out from the image forming apparatus 100 and removed to secure a space above the image forming section 270 . By lifting up the developing cartridge 220 of the target image forming station, it can be removed from the image forming section 270 . By attaching a new developing cartridge 220 to the image forming station and installing the image forming section 270 again in the image forming apparatus 100, the developing cartridge 220 can be replaced. Further, for example, when the endurance period of the photosensitive drum 210 has passed, in this embodiment, the entire image forming section 270 is configured to be replaced.

Positioning when installing the image forming unit 270 in the image forming apparatus 100 is performed as follows. Positioning bosses 213 (see FIGS. 1 and 3) are provided on the side plates 211 provided on the left and right sides of the image forming apparatus 100 described above, and protrude from the side plates 211 to determine the installation position of the image forming unit 270 . . When the image forming unit 270 placed on the rail member is guided by the rail member and inserted into the image forming apparatus 100 through the attachment/detachment opening 2 , the engaging portion 271 of the image forming unit 270 engages with the positioning boss 213 . Positioning of the image forming unit 270 is performed by the contact. Further, when the image forming section 270 is positioned in this way, the positioning holes 352 (see FIG. 4) provided for each image forming station in the left and right pair of the image forming section 270 are aligned with the guide holes 214 and 214 described later. 215, 216, 217 are also positioned.

[Configuration of exposure unit]
Next, the exposure unit 12 will be explained. As described above, the exposure unit 12 used in this embodiment is a device that forms an electrostatic latent image on the photosensitive drum 210 charged by the charger 212. In order to downsize the image forming apparatus 100, the LED It uses an array method. The LED array type exposure unit 12 is characterized in that a plurality of light emitting points are arranged close to the surface of the photosensitive drum 210 along the rotation axis direction of the photosensitive drum 210 .

FIG. 5 is a perspective view showing a cross-section of the LED exposure head 105, which is an optical print head positioned at the tip of the exposure unit 12, cut at substantially the center in the longitudinal direction. The LED exposure head 105 has an elongated shape extending in one direction, and is arranged parallel to the rotational axis of the photosensitive drum 210 in the image forming apparatus 100 . The LED exposure head 105 has an LED mounting substrate 303 on which an LED array 304, which is an example of a light emitting element, is mounted. The LED exposure head 105 also includes a lens assembly 301 for condensing the light beam emitted from the LED array 304 and forming an image on the photosensitive drum 210 . The lens assembly 301 has a configuration in which cylindrical rod lenses through which light beams pass are integrated. Furthermore, the LED exposure head 105 includes a housing 300 that positions and supports the LED mounting board 303 and the lens assembly 301 with high precision.

The LED mounting substrate 303 has a shape extending in one direction, and as shown in FIG. is implemented multiple times. Electronic components (not shown) for controlling light emission of the LED array 304 are mounted on the surface of the LED mounting substrate 303 opposite to the surface on which the LED array 304 is mounted.

The lens assembly 301 is an optical component having a rectangular parallelepiped shape extending in one direction and having cylindrical glass rod lenses arranged in a zigzag pattern through which light beams pass. FIG. 6 is a cross-sectional view of the LED exposure head 105. As shown in FIG. A light beam emitted from the LED array 304 becomes an incident beam 307 and enters a plurality of rod lenses forming the lens assembly 301 . The light beam that has passed through the plurality of rod lenses becomes an output beam 308 , is output from the lens assembly 301 , and forms an image on the surface of the photosensitive drum 210 .

The housing 300 is a member formed by injection molding a filler-containing resin having both high rigidity and heat resistance. The housing 300 precisely positions and fixes the lens assembly 301 and the LED mounting board 303 .

[Exposure head support mechanism]
FIG. 7 is a perspective view showing the shape of the housing 300 of the LED exposure head 105. As shown in FIG. As shown in FIG. 7, projection-shaped exposure guide engagement bosses 350 and positioning bosses 351 (details will be described later) are arranged at both ends of the housing 300 in the longitudinal direction. The exposure guide engaging boss 350 is roughly engaged with guide holes 214, 215, 216 and 217, which are grooves provided in the side plate 211 shown in FIGS. 1 and 3 corresponding to the respective image stations. The LED exposure head 105 can be moved along the shapes of the guide holes 214, 215, 216, and 217 by an advancing/retreating mechanism, which will be described later. Guide holes 214 , 215 , 216 and 217 are formed in a pair of side plates 211 provided on both sides of image forming apparatus 100 . The guide holes 214 , 215 , 216 , and 217 each have an arcuate shape with a convex curvature from the attachment/detachment opening 2 in FIGS. 1 and 3 toward the inside of the image forming apparatus 100 . Further, the curvature of each guide hole is different, and the curvature of the guide hole increases from the attachment/detachment opening 2 toward the inside of the image forming apparatus 100 .

Next, a method for supporting the LED exposure head 105 will be described with reference to FIG. As shown in FIG. 1 , the LED exposure head 105 is held within the image forming apparatus 100 by a first arm 106 and a second arm 107 . The first arm 106 and the second arm 107 are fitted to a cylindrical shaft 108 (second shaft) whose axis is fixed vertically below the shaft 109, and are rotatable relative to each other. . Further, the shafts 108 provided for each image forming station are also fitted with holes (described later) formed in the connecting member 111, are rotatably attached to the connecting member 111, and are arranged in a straight line. there is

The first arm 106, the second arm 107, and the shaft 108 are arranged at respective image forming stations for yellow (Y), magenta (M), cyan (C), and black (BK), respectively. Further, the first arm 106, the second arm 107, and the shaft 108 are arranged as a pair on the left and right outside side plates 211 provided on both sides inside the image forming apparatus 100 (on the side other than the storage area of the image forming section 270). ing. Further, a pair of left and right connecting members 111 that are fitted with the above-described shaft 108 are similarly arranged on the outside of the side plate 211 (on the side other than the housing area of the image forming section 270). The first arm 106 protrudes outward from the pair of side plates 211 and is rotatably supported around a shaft 109 (first shaft) having a fixed axis. An exposure unit 12 having an LED exposure head 105 is attached via an elastic member 110 to the end of the second arm 107 opposite to the end connected to the shaft 108 .

The LED exposure head 105 faces downward so that the lens assembly 301 faces the surface of the photosensitive drum 210 when the cover 1 is closed and the image can be formed as shown in FIG. At this time, the precision surface of the housing 300 is urged toward the precision surface of the photosensitive drum 210 by the elastic member 110 provided at the end of the second arm 107 . The precision surfaces of the photosensitive drum 210 and housing 300 abut each other to ensure that the imaging position of the emitted beam 308 (see FIG. 6) is on the surface of the photosensitive drum 210 . Regarding the positioning of the LED exposure head 105 with respect to the photosensitive drum 210, the positioning bosses 351 provided at both ends of the housing 300 are aligned with the positioning holes 352 (see FIG. 4) provided in the image forming section 270 as a pair of left and right positioning holes. mated to. Thereby, positioning of the LED exposure head 105 with respect to the photosensitive drum 210 is performed.

[Exposure head movement mechanism]
For example, when pulling out the image forming section 270 to replace the developing cartridge 220, if the LED exposure head 105 is in the state (first position) shown in FIG. , the image forming unit 270 cannot be pulled out. A first position is a position when the LED exposure head 105 exposes the photosensitive drum 210 from above in the vertical direction. Therefore, this embodiment has a mechanism for moving (retracting) the LED exposure head 105 of each image forming station to a space above the image forming apparatus 100 in response to opening and closing operations of the cover 1 . 1 and 3, an advance/retreat mechanism for attaching/detaching the LED exposure head 105 to/from the image forming station when the cover 1 is opened/closed will be described.

In FIG. 1, an input gear 353 is fixed to the outside of the first arm 106a fitted to the shaft 109a closest to the cover 1 and rotatably supported by the shaft 109a. The image forming apparatus 100 is provided with a drive transmission mechanism for rotating the input gear 353 in order to retract the LED exposure head 105 upward in the image forming section 270 in conjunction with the opening operation of the cover 1 . there is

Specifically, gears 355, 356, 357, and 358 interposed between a rack gear 354 provided on the cover 1 and an input gear 353 constitute a drive transmission mechanism (driving mechanism). The rack gear 354 is an arc-shaped rack gear provided concentrically with the cover shaft 3, which is the rotation shaft of the cover 1, and has a large number of teeth (not shown) on its outer peripheral surface. Gears 355 to 358 are engaged with a rotation center shaft (not shown) projecting from side plate 211 . Gears 355 to 358 and input gear 353 also have a large number of teeth (not shown), and the teeth of adjacent gears are in mesh with each other. Therefore, when the cover 1 is opened from the state shown in FIG. 1 to the state shown in FIG. Accordingly, the gear 355 rotates the gear 356 counterclockwise. Similarly, gear 356 rotates gear 357 in a clockwise direction, gear 357 rotates gear 358 in a counterclockwise direction, and gear 358 rotates input gear 353 in a clockwise direction, causing input gear 353. Thus, the driving force transmitted from rack gear 354 to gear 355 is transmitted to gears 356, 357 and 358, respectively, and finally rotates input gear 353 clockwise.

When the input gear 353 rotates clockwise, since the input gear 353 is fixed to the first arm 106a supported by the shaft 109a, the rotation of the input gear 353 also causes the first arm 106a to rotate clockwise. Rotate. As a result, the end of the first arm 106a on the side of the shaft 108a rises (moves) about the shaft 109a in the upward direction of the paper surface of FIG. Along with this, the swingable connecting member 111 and the second arm 107a, which are connected to the end of the first arm 106a via the shaft 108a, also rise (move) upward in the plane of FIG. become. At this time, the LED exposure head 105a is connected to the second arm 107a. Therefore, the exposure guide engagement boss 350 provided at the end of the LED exposure head 105 a and engaged with the guide hole 214 also rises (moves) in the guide hole 214 along the shape of the guide hole 214 .

1, the first arms 106b, 106c, and 106d connected to the connecting member 111 via the shafts 108b, 108c, and 108d also move to the shafts 109b, 109c, and 109d. will rise upwards around Similarly, the second arms 107b, 107c, and 107d also rise upward, and along with this, the exposure guide engagement bosses 350 of the LED exposure heads 105b, 105c, and 105d also follow the shapes of the guide holes 215, 216, and 217. to ascend (move).

Thus, according to the opening operation of the cover 1, the input gear 353 rotates, and the connecting member 111 guides the LED exposure head 105 to the guide holes 214, 215, 216, and 217 so that the LED exposure head 105 conforms to the shape of the guide holes. move along. As a result, the LED exposure heads 105 for yellow (Y), magenta (M), cyan (C), and black (BK) retreat toward the top of the image forming apparatus 100 . When the exposure guide engaging boss 350 moves to the upper end of the guide holes 214, 215, 216, and 217 (second position), the LED exposure head 105 of each image forming station stops moving, and the state is changed to It is held (see FIG. 3). The second position is a retracted position vertically above the exposure position (first position) where the LED exposure head 105 exposes the photosensitive drum. In the open state of the cover 1 shown in FIG. 3, the LED exposure head 105 of each image forming station is retracted above the image forming section 270 so that the image forming apparatus can operate without contacting the image forming section 270 with the LED exposure head 105 . You can draw from 100.

On the other hand, when closing the cover 1, the LED exposure head 105 is moved to a predetermined position of each image forming station by performing an operation opposite to the operation described above. That is, when the cover 1 is closed after the cover 1 is opened as shown in FIG. Accordingly, the gear 355 rotates the gear 356 clockwise. Similarly, gear 356 rotates gear 357 in a counterclockwise direction, gear 357 rotates gear 358 in a clockwise direction, and gear 358 rotates input gear 353 in a counterclockwise direction to input Drive is transmitted to gear 353 . Thus, the driving force transmitted from rack gear 354 to gear 355 is transmitted to gears 356, 357 and 358, respectively, and finally rotates input gear 353 counterclockwise.

When the input gear 353 rotates counterclockwise, since the input gear 353 is fixed to the first arm 106a supported by the shaft 109a, the first arm 106a rotates counterclockwise as the input gear 353 rotates. Rotate in a circular direction. As a result, the end portion of the first arm 106a on the side of the shaft 108a descends (moves) toward the bottom of the paper surface of FIG. 3 with the shaft 109a as the center. Along with this, the connecting member 111 connected to the end of the first arm 106a via the shaft 108a and the second arm 107a also descend (move) downward in the plane of FIG. At this time, the exposure guide engagement boss 350 provided at the end of the LED exposure head 105a and engaged with the guide hole 214 also descends (moves) through the guide hole 214 along the shape of the guide hole 214. .

3, the first arms 106b, 106c, and 106d connected to the connecting member 111 via the shafts 108b, 108c, and 108d also move to the shafts 109b, 109c, and 109d. centered on the downward direction. Similarly, the second arms 107b, 107c, and 107d also descend downward, and along with this, the exposure guide engagement bosses 350 of the LED exposure heads 105b, 105c, and 105d are also aligned with the guide holes 215, 216, and 217. Descending along the shape.

In this manner, the input gear 353 rotates according to the closing operation of the cover 1, and the connecting member 111 rotates the LED exposure heads 105 for each of yellow (Y), magenta (M), cyan (C), and black (BK). descends toward the image forming section 270 . The positioning bosses 351 of the LED exposure head 105 of each image forming station are provided in pairs on the left and right sides of the image forming section 270 when the exposure guide engaging bosses 350 are moved to the bottom ends of the guide holes 214 , 215 , 216 and 217 . It fits with the locating hole 352 provided. Thereby, the LED exposure head 105 of each image forming station is positioned at a predetermined image forming position (see FIG. 1).

[Cleaning the lens of the exposure head]
In this embodiment, the amount of withdrawal from the photosensitive drum 210 of the LED exposure heads 105 for the respective colors of yellow (Y), magenta (M), cyan (C), and black (BK) when the cover 1 is opened is It is characterized by being different. Here, assume that the image forming stations are arranged in order of yellow (Y), magenta (M), cyan (C), and black (BK) from the front side to the rear side of the image forming apparatus 100 . As shown in FIG. 3, the yellow (Y) LED exposure head 105a, which is closer to the loading/unloading port 2, has the largest retraction amount from the photosensitive drum 210a, followed by magenta (M), cyan (C), and black (BK). quantity becomes smaller.

FIG. 8 is a cross-sectional view showing the state of the image forming apparatus 100 when dirt on the lens assembly 301 of the LED exposure head 105 is removed. FIG. 8 shows a state in which the cover 1 is opened and the image forming section 270 is pulled out from the image forming apparatus 100 in order to remove dirt from the lens assembly 301 . Then, in this state, the surface of the lens assembly 301 is accessed through the attachment/detachment opening 2, and dirt on the surface of the lens assembly 301 is removed using a cleaning member. At this time, the height of the LED exposure head 105 retracted from the photosensitive drum 210 from the image forming section 270 (not shown, see FIG. 3) is higher for the LED exposure head 105 of the image forming station closer to the attachment/detachment opening 2 . Conversely, the height of the LED exposure head 105 of the image forming station from the image forming section 270 becomes lower as it moves away from the loading port 2 toward the inside of the image forming apparatus 100 from the loading port 2 .

As indicated by the dashed line in FIG. 8, in a state in which the LED exposure head 105 is retracted from the photosensitive drum 210, each LED exposure head and the connecting member 111 approach the photosensitive drum 210 toward the back side (rear side) of the apparatus main body. It is slanted so that A connecting member 111 connects between the four shafts 108a to 108d. Here, the axis 108a is an intersection point that rotationally supports the first arm 106a and the second arm 107a. The axis 108b is an intersection point that rotationally supports the first arm 106b and the second arm 107b. The axis 108c is a point of intersection that rotationally supports the first arm 106c and the second arm 107c. The axis 108d is an intersection point that rotationally supports the first arm 106d and the second arm 107d.

The shaft 108 that rotatably supports the first arm 106 and the second arm 107 is driven by the rotation of each gear caused by the opening/closing operation of the cover 1, as described above. The yellow (Y) shaft 108a closest to the attachment/detachment port 2 is fitted into the connecting member 111 through a round hole and is rotatably supported. On the other hand, the magenta (M), cyan (C), and black (BK) shafts 108b, 108c, and 108d are fitted into the coupling member 111 in the form of long oval holes in the longitudinal direction. Therefore, the four shafts 108a to 108d also move in conjunction with the movement of the connecting member 111. As shown in FIG.

As described above, exposure guide engaging bosses 350 protrude from both ends of the housing 300 in the longitudinal direction of the housing 300 of each of the LED exposure heads 105a to 105d. These exposure guide engaging bosses 350 are fitted into the guide holes 214-217. As a result, the exposure guide engagement bosses 350 move along the guide holes 214 to 217 corresponding to the exposure guide engagement bosses 350 of the LED exposure heads 105a to 105d in conjunction with the movement of the connecting member 111. FIG.

Here, details of the shape of each of the guide holes 214 to 217 will be described. As shown in FIG. 8, each guide hole 214 to 217 has a different curvature. The curvature of the guide hole 214 corresponding to yellow (Y), which is closest to the loading port 2, is the smallest, and the curvature of the guide hole 217 corresponding to black (BK) is the largest. That is, the curvature is increased in the order of guide hole 217 corresponding to black (BK), guide hole 216 corresponding to cyan (C), guide hole 215 corresponding to magenta (M), and guide hole 214 corresponding to yellow (Y). It's getting smaller. In other words, as can be seen from FIG. 8, the closer the guide hole (the guide hole 217 corresponding to black (K)) to the front side of the apparatus main body, the steeper the slope. As a result, the amount of vertical movement of the exposure guide engagement boss 350 with respect to the unit amount of rotation of the gear 358 increases toward the front side of the apparatus main body.

Further, since the curvatures of the guide holes 214 to 217 are different, the intervals between the guide holes 214 to 217 in the horizontal direction are also different in the vertical direction. That is, the horizontal distance between the upper end of the guide hole 216 and the upper end of the guide hole 217 is narrower than the distance between the lower end of the guide hole 216 and the lower end of the guide hole 217 in the horizontal direction. Similarly, the horizontal distance between the upper end of the guide hole 215 and the upper end of the guide hole 216 is narrower than the distance between the lower end of the guide hole 215 and the lower end of the guide hole 216 in the horizontal direction. Similarly, the horizontal distance between the upper end of the guide hole 214 and the upper end of the guide hole 215 is narrower than the distance between the lower end of the guide hole 214 and the lower end of the guide hole 215 in the horizontal direction. Furthermore, since the curvature of each of the guide holes 214 to 217 is smaller toward the front side of the apparatus main body, the distance between the upper end of the guide hole 215 and the guide hole 217 is greater than the distance between the upper end of the guide hole 216 and the upper end of the guide hole 217 in the horizontal direction. The horizontal distance from the upper end of 216 is narrower. Furthermore, the horizontal distance between the upper ends of the guide holes 214 and 215 is narrower than the horizontal distance between the upper ends of the guide holes 215 and 216 . Here, since each of the shafts 108a to 108d is connected to the connecting member 111, the intervals between the shafts 108a to 108d adjacent to each other in the longitudinal direction of the connecting member 111 are constant. Similarly, the intervals between the exposure guide engagement bosses 350 corresponding to the LED exposure heads 105a-105d are also constant as indicated by broken lines in FIG. Since the curvatures of the guide holes 214 to 217 are different, as shown by broken lines in FIG. 105d are kept at regular intervals.

As described above, the height of the LED exposure head 105 retracted from the photosensitive drum 210 is higher for the LED exposure head 105 in the image forming station closer to the loading/unloading port 2 , and decreases as it moves away from the loading/unloading port 2 . , and is located on the lower side in the vertical direction. As a result, when cleaning dirt on the lens assembly 301, the lens assembly 301 of the LED exposure head 105 away from the attachment/detachment port 2 can be visually observed, and the risk of accidentally touching the lens assembly 301 during cleaning work is reduced. be done. Therefore, this facilitates the cleaning work for removing dirt adhering to the surface of the lens assembly 301 of the LED exposure head 105 .

As described above, according to this embodiment, it is possible to improve workability when cleaning the lens surface of the exposure head.

In Example 1, the lens assembly 301 of the LED exposure head 105 retracted from the photosensitive drum 210 faces the inside of the image forming apparatus 100 instead of the attachment/detachment opening 2 . In the second embodiment, an example will be described in which the lens assembly 301 of the LED exposure head 105 retracted from the photosensitive drum 210 faces the outside of the image forming apparatus 100 , that is, toward the attachment/detachment opening 2 . Since the configuration of the image forming apparatus 100 is the same except for some members, the same members and devices are denoted by the same reference numerals as in the first embodiment, and description thereof is omitted.

[Exposure head movement mechanism]
9 is a schematic cross-sectional view of the image forming apparatus 100 with the cover 1 closed, and FIG. 10 is a schematic cross-sectional view of the image forming apparatus 100 with the cover 1 open. be. As shown in FIG. 10, when the LED exposure head 105 is at the retracted position, the lens assembly 301 of the LED exposure head 105 of the image forming station closest to the loading/unloading port 2 is the highest. Further, as in the first embodiment, the height of the lens assembly 301 of the LED exposure head 105 decreases in the direction away from the attachment/detachment opening 2 , ie, in the direction inside the image forming apparatus 100 . The present embodiment differs from the first embodiment in that all the lens aggregates 301 of the LED exposure head 105 are oriented toward the attachment/detachment opening 2 .

In the second embodiment, the way in which the first arm 106 and the second arm 107 are folded differs from that in the first embodiment so that the lens assembly 301 of the LED exposure head 105 faces the direction of the attachment/detachment opening 2 . That is, in Embodiment 1, when the cover 1 in FIG. At the same time, the first arm 106 rotates clockwise. On the other hand, in this embodiment, when the cover 1 in FIG. 9 is closed and the cover 1 is open in FIG. 10, the first arm 106 rotates counterclockwise. reverses the direction of rotation. Therefore, the number of gears required between the rack gear 354 and the input gear 353 integrally fixed with the first arm 106 is reduced from the four in the first embodiment to gears 355, 356, and 357 shown in FIG. It becomes 3 pieces.

When the cover 1 is opened from the closed state shown in FIG. 9 , the rack gear 354 rotates the gear 355 clockwise according to the movement of the cover 1 . Accordingly, the gear 355 rotates the gear 356 counterclockwise. Similarly, gear 356 rotates gear 357 in a clockwise direction, and gear 357 rotates input gear 353 in a counterclockwise direction to transmit drive to input gear 353 . Thus, the driving force transmitted from rack gear 354 to gear 355 is transmitted to gears 356 and 357, respectively, and finally rotates input gear 353 counterclockwise.

When the input gear 353 rotates counterclockwise, since the input gear 353 is fixed to the first arm 106a supported by the shaft 109a, the first arm 106a also rotates counterclockwise as the input gear 353 rotates. rotate in the direction As a result, the end portion of the first arm 106a on the side of the shaft 108a rises about the shaft 109a in the upward direction in FIG. Along with this, the connecting member 111 connected to the end of the first arm 106a via the shaft 108a and the second arm 107a are also raised upward on the plane of FIG. At this time, the exposure guide engagement boss 350 provided at the end of the LED exposure head 105a and engaged with the guide hole 221 also rises through the guide hole 221 along the shape of the guide hole 221 .

9, the first arms 106b, 106c, and 106d connected to the connecting member 111 via the shafts 108b, 108c, and 108d also move to the shafts 109b, 109c, and 109d. will rise upwards around Similarly, the second arms 107b, 107c, and 107d also rise upward, and along with this, the exposure guide engagement bosses 350 of the LED exposure heads 105b, 105c, and 105d also follow the shapes of the guide holes 222, 223, and 224. to rise.

In this manner, the input gear 353 rotates according to the opening operation of the cover 1, and the LED exposure head 105 is guided by the guide holes 221, 222, 223, and 224 by the connecting member 111, and is guided along the shape of the guide holes. to move. As a result, the LED exposure heads 105 for yellow (Y), magenta (M), cyan (C), and black (BK) retreat above the image forming apparatus 100 . Then, the LED exposure head 105 of each image forming station stops moving when the exposure guide engaging boss 350 moves to the upper end of the guide holes 221, 222, 223, and 224, and this state is maintained (FIG. 10). reference). In the open state of the cover 1 shown in FIG. 10, the LED exposure head 105 of each image forming station moves (retracts) above the image forming section 270 so that the image forming section 270 can be pulled out from the image forming apparatus 100. become.

On the other hand, when closing the cover 1, the LED exposure head 105 is moved to a predetermined position of each image forming station by performing an operation opposite to the operation described above. That is, when the cover 1 is closed after the cover 1 is opened as shown in FIG. Accordingly, the gear 355 rotates the gear 356 clockwise. Similarly, gear 356 rotates gear 357 in a counterclockwise direction, and gear 357 rotates input gear 353 in a clockwise direction to transmit drive to input gear 353 . Thus, the driving force transmitted from rack gear 354 to gear 355 is transmitted to gears 356 and 357, respectively, and finally rotates input gear 353 clockwise.

When the input gear 353 rotates clockwise, since the input gear 353 is fixed to the first arm 106a supported by the shaft 109a, the rotation of the input gear 353 causes the first arm 106a to rotate clockwise. Rotate. As a result, the end of the first arm 106a on the side of the shaft 108a descends toward the bottom of the paper surface of FIG. 10 with the shaft 109a as the center. Along with this, the connecting member 111 connected to the end of the first arm 106a via the shaft 108a and the second arm 107a also descend downward in the plane of FIG. At this time, the exposure guide engagement boss 350 provided at the end of the LED exposure head 105a and engaged with the guide hole 221 also descends through the guide hole 221 along the shape of the guide hole 221 .

10, the first arms 106b, 106c, and 106d connected to the connecting member 111 via the shafts 108b, 108c, and 108d also move to the shafts 109b, 109c, and 109d. centered on the downward direction. Similarly, the second arms 107b, 107c, and 107d also descend downward, and along with this, the exposure guide engaging bosses 350 of the LED exposure heads 105b, 105c, and 105d also change the shape of the guide holes 222, 223, and 224. descend along.

In this manner, the input gear 353 rotates according to the closing operation of the cover 1, and the connecting member 111 rotates the LED exposure heads 105 for each of yellow (Y), magenta (M), cyan (C), and black (BK). descends toward the image forming section 270 . The positioning bosses 351 of the LED exposure head 105 of each image forming station are provided in pairs on the left and right sides of the image forming section 270 when the exposure guide engaging bosses 350 are moved to the lower ends of the guide holes 221, 222, 223, and 224. It fits with the locating hole 352 provided. Thereby, the LED exposure head 105 of each image forming station is positioned at a predetermined image forming position (see FIG. 9).

[Cleaning the lens of the exposure head]
FIG. 11 is a cross-sectional view of the image forming apparatus 100 with the image forming unit 270 removed from the state of FIG. As shown in FIG. 11, in this embodiment, unlike the first embodiment, the lens assembly 301 faces toward the attachment/detachment opening 2 . Therefore, the lens assembly 301 to be cleaned can be easily viewed from the attachment/detachment opening 2, and the cleaning work is easy because the cleaning surface faces the attachment/detachment opening 2 side. Also, as in the first embodiment, the position of the LED exposure head 105 from the image forming unit 270 of the lens assembly 301 is the highest at the image forming station closest to the loading/unloading port 2 , and increases as the distance from the loading/unloading port 2 increases. 2) becomes lower as it advances from the exit 2 toward the inside of the image forming apparatus 100). Therefore, the visibility of the lens assembly 301 of the image forming station located inside the image forming apparatus 100 away from the attachment/detachment port 2 is high as in the first embodiment. 11, in which the LED exposure head 105 is retracted upward, the connecting member 111 is inclined downward as indicated by the dashed line in the drawing toward the inside of the image forming apparatus 100 from the attachment/detachment opening 2. As shown in FIG.

In Examples 1 and 2, the LED exposure head 105 is arranged above the photosensitive drum 210 and the photosensitive drum 210 is exposed. , 2 can be applied. Also in this case, similarly to Embodiments 1 and 2, the retraction amount of the LED exposure head 105 of the image forming station closest to the loading/unloading port 2 is the largest, and the LED exposure of the image forming station located away from the loading/unloading port 2 is the largest. The retraction amount of the head 105 is made to decrease in order. Thereby, the cleaning work of the lens assembly 301 can be efficiently performed.

As described above, according to this embodiment, it is possible to improve workability when cleaning the lens surface of the exposure head.

1 cover 2 attachment/detachment opening 105 LED exposure head 210 photosensitive drum 270 image forming unit

Claims (10)

An image forming apparatus having an opening formed in a side surface of an apparatus main body and having a housing capable of moving between a position attached to the apparatus main body and a position pulled out from the apparatus main body through the opening,
a plurality of photosensitive drums arranged in parallel along the direction of movement of the housing and rotatable with respect to the housing;
a plurality of optical print heads provided in the apparatus main body and movable between an exposure position where the photosensitive drum is exposed from above in the vertical direction and a retracted position where the exposure position is retracted vertically above the exposure position;
a cover that is rotatably provided with respect to the apparatus main body and is rotatably movable between a closed position that closes the opening and an open position that opens the opening;
The plurality of optical print heads are located at the exposure position when the cover is located at the closed position, and the plurality of optical print heads are located at the retracted position when the cover is located at the open position. a moving mechanism for moving the plurality of optical print heads in conjunction with rotation of the cover;
with
each of the optical print heads when positioned at the retracted position is positioned lower in the vertical direction as the optical print head is positioned farther from the opening in the moving direction of the housing ;
projections extending in the longitudinal direction are formed at both ends of the optical print head in the longitudinal direction of the optical print head,
the apparatus main body includes a side plate having a groove in which the protrusion is fitted, at a position facing the optical print head in the longitudinal direction;
the groove has an arc shape,
The image forming apparatus according to claim 1, wherein the arc-shaped curvature differs according to the corresponding optical print head . The moving mechanism is
a first arm that rotates about a first shaft whose axis is fixed with respect to the device main body;
a second arm rotatably connected to the first arm about a second shaft whose axis is fixed to the first arm vertically below the first shaft; ,
with
The optical print head is provided on the second arm,
The position of the second shaft when the cover is in the open position is vertically higher than the position of the second shaft when the cover is in the closed position. The image forming apparatus according to claim 1 . a drive mechanism that rotates the first arm in conjunction with rotation of the cover;
the first arm rotates in conjunction with the rotation of the cover from the closed position to the open position to move the second shaft vertically upward;
3. The first arm rotates in conjunction with the rotation of the cover from the open position to the closed position to move the second shaft downward in the vertical direction. 2. The image forming apparatus according to 2 above. The first arm and the second arm are provided corresponding to each of the plurality of optical print heads, and the respective second shafts are rotatably attached to connecting members and arranged in a straight line. 4. The image forming apparatus according to claim 2, wherein the image forming apparatus comprises: 5. The image forming apparatus according to any one of claims 1 to 4, wherein the optical print head, which moves in association with rotation of the cover, moves along the groove. 6. The image forming apparatus according to any one of claims 1 to 5 , wherein the curvature of the arc shape increases with distance from the opening to the optical print head . The drive mechanism rotates in conjunction with the rotation of the cover and has a plurality of gears that transmit the rotation,
one of the first shafts has a gear to which the rotation of the gear of the drive mechanism is transmitted and rotates integrally with the one first shaft;
The moving mechanism moves the optical print head by rotating the first arm supported by the one first shaft with the gear of the one first shaft. 4. The image forming apparatus according to claim 3. 8. The image forming apparatus according to claim 7 , wherein the one first axis is the first axis of the optical print head closest to the opening among the optical print heads. The optical print head has a lens for condensing the light for exposing the photosensitive drum onto the photosensitive drum,
9. The image according to any one of claims 1 to 8 , wherein the lens faces the side where the opening is arranged when the optical print head is moved to the retracted position. forming device. The optical print head has a lens for condensing the light for exposing the photosensitive drum onto the photosensitive drum,
9. The lens according to any one of claims 1 to 8 , wherein when the optical print head is moved to the retracted position, the lens faces a direction opposite to the side on which the opening is arranged. 2. The image forming apparatus according to item 1.

Images