JP2012068568A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming device capable of positioning exposure members in the sub-scanning direction, and improve flexibility of the layout within a body housing.SOLUTION: An image forming device comprises: a body housing provided with an apertural area; a cover (an upper cover 12) which is rotatably attached to the body housing and is rotated between a closed position covering the apertural area and an open position uncovering the apertural area; photoreceptors (photosensitive drums 53) which are rotatably installed on the body housing and on which electrostatic latent images are formed; and exposure members (LED heads 41) which are provided movably against the cover and expose the photoreceptors along the horizontal scanning direction when the cover is in the closed position. The body housing is provided with positioning members (positioning parts 54) contacting with the exposure members in the sub-scanning direction of the exposure members, and the cover is provided with press members (compression coil springs 110) which press the exposure members toward the positioning members.

Description

  The present invention relates to an image forming apparatus including an exposure member that exposes a photoreceptor along a main scanning direction, and a cover that is provided so that the exposure member is movable.

  Conventionally, an exposure member in which a plurality of LEDs are arranged, an upper cover that supports the exposure member so as to be movable via a spring, a main body case that rotatably supports the upper cover, and a main body case, An image forming apparatus having a photosensitive drum exposed by an exposure member is known (see Patent Document 1). In this technique, in order to position the exposure member in the sub-scanning direction with respect to the photosensitive drum, a positioning member that contacts the exposure member in the sub-scanning direction, and a biasing member that presses the exposure member toward the positioning member; However, when the upper cover is closed, the exposure member is sandwiched between the positioning member and the urging member and positioned in the sub-scanning direction.

JP 2010-52154 A

  However, the above-described image forming apparatus has a problem in that the biasing member for positioning the exposure member in the sub-scanning direction is provided in the main body casing, so that the degree of freedom of layout in the main body casing is reduced.

  SUMMARY An advantage of some aspects of the invention is that it provides an image forming apparatus that can reliably position an exposure member in the sub-scanning direction and can improve the degree of freedom of layout in a main body housing.

  The present invention for solving the above problems includes a main body housing provided with an opening, a closed position that is rotatably provided in the main body housing and covers the opening, and an open position that opens the opening. A cover that rotates between, a photosensitive member that is rotatably provided on the main body casing and on which an electrostatic latent image is formed, a cover that is movable with respect to the cover, and the cover is closed. An exposure member that exposes the photoconductor along the main scanning direction when in position, the image forming apparatus including the main body housing and the exposure member in the sub-scanning direction of the exposure member. The contact member is provided with a positioning member, and the biasing member for biasing the exposure member toward the positioning member is provided on the cover.

  According to the present invention, since the urging member is provided on the cover, the degree of freedom of the layout of the main body casing can be improved as compared with a structure in which both the urging member and the positioning member are provided on the main body casing. Further, since the exposure member is biased by the positioning member by the biasing member provided on the cover, the exposure member can be reliably positioned in the sub-scanning direction.

  According to the present invention, the exposure member can be reliably positioned in the sub-scanning direction, and the degree of freedom of layout in the main body housing can be improved.

1 is an explanatory diagram illustrating an overall configuration of an electrophotographic color printer. FIG. It is explanatory drawing which expands and shows the structure around a LED unit. It is explanatory drawing which looked at the LED unit from the front. It is explanatory drawing (a) which shows the state which raised the upper cover from the closed position for a while, and explanatory drawing (b) which shows the state which put the upper cover in the open position. It is explanatory drawing which shows the cam interlock | cooperated with opening and closing of an upper cover, The figure (a) which shows the state when an upper cover is a closed position, The figure (b) which shows the state which raised the upper cover from the closed position a little, It is a figure (c) which shows a state when an upper cover is an open position.

  Next, embodiments of the present invention will be described in detail with reference to the drawings as appropriate. In the following description, the overall configuration of the color printer will be described first, and then the details of the features of the present invention will be described.

  In the following description, the direction will be described with reference to the user when using the color printer. That is, in FIG. 1, the left side toward the paper surface is “front side (front side)”, the right side toward the paper surface is “rear side (back side)”, the back side toward the paper surface is “left side”, and it faces the paper surface. Let the near side be the “right side”. In addition, the vertical direction toward the page is defined as the “vertical direction”.

  As shown in FIG. 1, the color printer 1 includes a paper feeding unit 20 that supplies a sheet P (recording sheet) and an image forming unit 30 that forms an image on the fed paper P. And a paper discharge section 90 for discharging the paper P on which the image is formed.

  An opening 11 that opens upward is formed on the upper wall of the main body casing 10, and an upper cover 12 that opens and closes the opening 11 is rotatably provided. Specifically, the upper cover 12 rotates between a closed position that covers the opening 11 (position in FIG. 5A) and an open position that opens the opening 11 (position in FIG. 5C). It is like that.

  The paper feed unit 20 includes a paper feed tray 21 that accommodates the paper P and a paper transport device 22 that transports the paper P from the paper feed tray 21 to the image forming unit 30.

  The image forming unit 30 includes four LED units 40, four process cartridges 50, a transfer unit 70, and a fixing unit 80 so as to correspond to four (plural) colors.

  The LED unit 40 includes a plurality of LEDs and is provided so as to be rotatable with respect to the upper cover 12. When the upper cover 12 is in the closed position, the LED unit 40 exposes a photosensitive drum 53 as an example of a photosensitive member to be described later along the main scanning direction (the axial direction of the photosensitive drum 53). The details around the LED unit 40 will be described later.

  The process cartridge 50 is arranged side by side in the front-rear direction, and includes a photosensitive drum 53, a charger (not shown), a known developing roller that is not shown, a toner storage chamber, and the like. The photosensitive drum 53 may be rotatably supported on the main body housing 10 via the process cartridge 50 by being provided rotatably on the housing of the process cartridge 50, and the rotational axis of the photosensitive drum 53 may be It may be supported directly on the main body housing 10 so as to be rotatable.

  The transfer unit 70 is provided between the paper feeding unit 20 and each process cartridge 50 and includes a driving roller 71, a driven roller 72, a conveyance belt 73, and a transfer roller 74.

  The driving roller 71 and the driven roller 72 are arranged in parallel in a spaced manner in the front-rear direction, and a conveyance belt 73 formed of an endless belt is stretched between them. The outer surface of the conveyance belt 73 is in contact with each photosensitive drum 53. In addition, four transfer rollers 74 that sandwich the conveyor belt 73 between the photosensitive drums 53 are arranged inside the conveyor belt 73 so as to face the photosensitive drums 53. A transfer bias is applied to the transfer roller 74 by constant current control during transfer.

  The fixing unit 80 is disposed on the rear side of each process cartridge 50 and the transfer unit 70, and includes a heating roller 81 and a pressure roller 82 that is disposed to face the heating roller 81 and presses the heating roller 81.

  In the image forming unit 30 configured as described above, first, the surface of each photosensitive drum 53 is uniformly charged by a charger and then exposed by each LED unit 40. As a result, the potential of the exposed portion is lowered, and an electrostatic latent image based on the image data is formed on each photosensitive drum 53. Thereafter, toner is supplied to the electrostatic latent image from the developing roller, so that the toner image is carried on the photosensitive drum 53.

  Next, the paper P supplied onto the conveying belt 73 passes between each photosensitive drum 53 and each transfer roller 74, so that the toner image formed on each photosensitive drum 53 is transferred onto the paper P. The Then, as the paper P passes between the heating roller 81 and the pressure roller 82, the toner image transferred onto the paper P is thermally fixed.

  The paper discharge unit 90 mainly includes a plurality of transport rollers 91 that transport the paper P. The sheet P on which the toner image has been transferred and heat-fixed is transported by the transport roller 91 and discharged outside the main body housing 10.

<Structure around the LED unit>
Next, the structure around the LED unit 40, which is a characteristic part of the present invention, will be described in detail.
As shown in FIGS. 2 and 3, the LED unit 40 includes an LED head 41 as an example of an exposure member and a support frame 42 that supports the LED head 41, and is suspended by the LED support member 13 provided on the upper cover 12. Supported in a lowered state. In FIG. 2 (the same applies to FIG. 5 described later), only one LED unit 40 is illustrated and the other LED units 40 are omitted so that the structure around the LED unit 40 can be easily understood.

  The LED head 41 includes a plurality of LED arrays 41A configured by arranging a large number of LEDs on a semiconductor chip, a head frame 41B, and a lens array 41C.

  The plurality of LED arrays 41A are arranged in a zigzag shape (a plurality of rows) in accordance with a predetermined pixel pitch in the left-right direction (axial direction of the photosensitive drum 53), and appropriately emit light when selectively driven. The light is intermittently emitted toward the photosensitive drum 53. Specifically, each LED array 41 </ b> A receives a signal from a control device (not shown) based on image data to be formed, emits light, and exposes the photosensitive drum 53.

  The head frame 41B is made of resin and supports the plurality of LED arrays 41A and the lens array 41C. A pair of extending portions 41D extending downward from the lens array 41C are formed at the left and right end portions of the lower surface of the head frame 41B, and guide rollers 43 as an example of a spacing member are provided in each extending portion 41D. Is rotatably provided.

  Each guide roller 43 comes into contact with the surface of the photosensitive drum 53 so that the distance between the light emitting surface 41E of the LED head 41 (the lower surface of the lens array 41C) and the surface of the photosensitive drum 53 is maintained. Yes.

  The lens array 41C forms an image of the light emitted from each LED array 41A on the photosensitive drum 53. A glass GRIN lens (cylindrical lens) having a light emitting surface 41E formed in a planar shape is staggered. Are arranged side by side.

  The support frame 42 includes a base portion 42A extending in the left-right direction, a hook 42B extending downward from the base portion 42A, and an extending portion 42C extending upward from the base portion 42A.

  On both left and right side surfaces of the base portion 42A, rotation shaft portions 42D that protrude outward in the left-right direction are formed. Then, each rotation shaft portion 42 </ b> D is rotatably supported by the LED support member 13, so that the support frame 42 and the LED head 41 can be rotated with respect to the upper cover 12.

  A coil spring 44 for pressing the LED head 41 toward the photosensitive drum 53 is provided between the base portion 42 </ b> A and the LED head 41. Thus, when the photosensitive drum 53 is exposed by the LED head 41, the guide roller 43 is reliably brought into contact with the photosensitive drum 53, and the distance between the light emitting surface 41E of the LED head 41 and the surface of the photosensitive drum 53 is made constant. It is possible to do.

  The lower ends of the hooks 42B are formed in a bowl shape, and are provided one pair at a predetermined interval in the left-right direction. Each pair of hooks 42 </ b> B is disposed inside the both ends of the LED head 41 in the left-right direction (main scanning direction) of the light emitting surface 41 </ b> E. Each pair of hooks 42B is disposed so as to sandwich the head frame 41B forward and backward, and the hook-like lower end engages with a hole 41F formed in the head frame 41B, thereby having a predetermined play. The head frame 41B is supported so as to be suspended.

  The extending portion 42C has a pin-like portion 42E protruding in the left-right direction at the upper end thereof. The pin-like portion 42E is connected to a retraction mechanism 100 provided in the upper cover 12, and is moved by the retraction mechanism 100 to move back and forth. In particular, the extending portion 42 </ b> C is a compression coil spring 110 as an example of an urging member constituting the retracting mechanism 100 when the LED head 41 is located at an exposure position (position in FIG. 2) for exposing the photosensitive drum 53. Is biased backwards. As a result, the LED head 41 is biased forward via the support frame 42 that swings clockwise in the drawing, and the LED head 41 is positioned by the process cartridge 50 as an example of a positioning member provided in the main body housing 10. The unit 54 is in contact with the photosensitive drum 53 in the sub-scanning direction by contacting the portion 54 in the sub-scanning direction (front-back direction).

  When the upper cover 12 is in the closed position (position in FIG. 2), the retracting mechanism 100 places the light emitting surface 41E of the LED head 41 at the exposure position (position in FIG. 2), and the upper cover 12 is in the open position. When in the (position of FIG. 4 (b)), the light emitting surface 41E of the LED head 41 is arranged at the retracted position (position of FIG. 4 (b)) closer to the upper cover 12 side than the exposure position. It is configured.

  Specifically, the retracting mechanism 100 includes the compression coil spring 110 described above, a support member 120 that supports the compression coil spring 110, a slide member 130 that is biased rearward by the compression coil spring 110, and the slide member 130. And a cam 140 that pushes forward against the urging force.

  The slide member 130 is supported by the upper cover 12 so as to be movable in the front-rear direction, and in the position corresponding to the pin-like portion 42E of each LED unit 40, the pin-like portion 42E is moved in the front-rear direction (the upper cover 12 is closed). Four engagement holes 131 are formed to be engaged in the front-rear direction). The engagement hole 131 is formed in a long hole shape that allows the pin-like portion 42E to move when the LED unit 40 swings between the exposure position and the retracted position.

  The cam 140 includes a cam surface 141 for pressing the slide member 130 forward. As shown in FIG. 5A, the cam 140 is connected to the main body housing 10 via a link member 142, and thereby rotates in conjunction with opening and closing of the upper cover 12. ing.

  Specifically, when the upper cover 12 is closed, the cam 140 has a non-pressing position (a position corresponding to the exposure position) in which the cam surface 141 is disengaged from the slide member 130 (see FIG. 2). Position). Then, as shown in FIG. 5B, when the upper cover 12 is opened, the cam surface 141 is gradually rotated clockwise, and the slide member 130 is resisted against the biasing force of the compression coil spring 110. And gradually push forward.

  When the upper cover 12 is opened to the maximum, the cam 140 is positioned at a pressing position (a position corresponding to the retracted position, the position shown in FIG. 4B) that presses the slide member 130 forward. By configuring the cam 140 in this manner, each LED unit 40 swings between the exposure position and the retracted position according to the opening / closing of the upper cover 12 by the action of the cam 140 and the compression coil spring 110. It comes to move. Note that, at the exposure position, a slight gap is formed between the cam 140 and the slide member 130, whereby each LED unit 40 is biased to the positioning portion 54 by the compression coil spring 110. ing.

  The compression coil spring 110 has a front end fixed to a support member 120 fixed to the upper cover 12, and is configured to urge the slide member 130 rearward at the rear end. The LED head 41 is urged toward the front positioning portion 54 via the frame 42 to contribute to the positioning of the LED head 41.

  Further, since the compression coil spring 110 is configured to urge the slide member 130 rearward in this way, the LED head 41 is moved from the retracted position (position shown in FIG. 4B) to the exposure position (shown in FIG. 2). Is biased toward (position). As a result, the compression coil spring 110 moves the LED head 41 from the retracted position to the exposure position when the upper cover 12 is closed as shown in the order of FIGS. 4B, 4A, and 2. And also serves as a part of the retracting mechanism 100.

  Further, the compression coil spring 110 urges the LED head 41 forward (the same direction as the moving direction D1 of the surface 53A of the photosensitive drum 53 facing the LED head 41) via the slide member 130 and the support frame 42. The direction in which the LED head 41 (guide roller 43) is pushed by the photosensitive drum 53 coincides with the urging direction, and the urging force applied to the LED head 41 can be stabilized (see FIG. 2).

  Furthermore, the compression coil spring 110 urges the inner portions of the LED head 41 from both ends in the left-right direction of the light emitting surface 41E by arranging the pair of hooks 42B as described above. Thereby, the LED head 41 can be shortened in the left-right direction.

According to the above, the following effects can be obtained in the present embodiment.
Since the compression coil spring 110 for positioning the LED head 41 is provided on the upper cover 12, the layout of the main body casing 10 can be more flexible than a structure in which both the urging member and the positioning member are provided on the main body casing 10. Can be improved. Further, since the LED head 41 is urged to the positioning portion 54 by the compression coil spring 110 provided on the upper cover 12, the LED head 41 can be reliably positioned in the sub-scanning direction.

  Further, since the positioning portion 54 is formed integrally with the process cartridge 50 having the photosensitive drum 53, the positioning accuracy of the LED head 41 with respect to the photosensitive drum 53 can be improved.

  The compression coil spring 110 urges the LED head 41 in the same direction as the moving direction D1 of the surface 53A of the photosensitive drum 53 facing the LED head 41 (the direction in which the guide roller 43 is pressed by the photosensitive drum 53). The urging force applied to 41 can be stabilized.

  Since the compression coil spring 110 for positioning the LED head 41 also serves as a part of the retracting mechanism 100, the configuration can be simplified compared to a structure in which a spring other than the positioning biasing member is provided in the retracting mechanism. .

  Since the compression coil spring 110 urges a portion of the LED head 41 that is on the inner side of the both end edges in the left-right direction of the light emitting surface 41E, the LED head 41 can be shortened in the left-right direction.

  Since a plurality of photosensitive drums 53 and LED heads 41 are provided so as to correspond to a plurality of colors, the main body is compared with a structure in which a plurality of urging members that urge LED heads corresponding to a plurality of colors are provided in the main body housing. When the process cartridge 50 is mounted on the housing 10, the compression coil spring 110 does not get in the way, so that the mounting can be performed smoothly.

In addition, this invention is not limited to the said embodiment, It can utilize with various forms so that it may illustrate below.
In the above embodiment, the upper cover 12 is exemplified as a cover for supporting the exposure member. However, the present invention is not limited to this, and may be, for example, a front cover or a side cover depending on the orientation of the LED head.

  In the above-described embodiment, the photosensitive drum 53 is exemplified as the photosensitive member. However, the present invention is not limited to this, and may be, for example, a belt-shaped photosensitive member.

  In the above embodiment, the LED head 41 is provided on the upper cover 12 so as to be rotatable. However, the present invention is not limited to this, and the LED head may be movable with respect to the upper cover. The LED head may be movable back and forth and up and down.

  In the above-described embodiment, the process cartridge 50 having the positioning portion 54 as the positioning member has been exemplified. However, the present invention is not limited to this, and for example, a component other than the process cartridge is used as the positioning member. It may be fixed to.

  In the embodiment, the compression coil spring 110 is exemplified as the urging member. However, the present invention is not limited to this, and may be, for example, a leaf spring or a wire spring.

  In the above-described embodiment, the guide roller 43 is exemplified as the spacing member, but the present invention is not limited to this, and may be a member that does not rotate, for example.

  In the above embodiment, the present invention is applied to the color printer 1. However, the present invention is not limited to this, and the present invention may be applied to other image forming apparatuses such as monochrome printers, copiers, and multifunction machines. Good.

  In the embodiment, the LED head 41 having the plurality of LED arrays 41A arranged in a staggered pattern (a plurality of rows) is exemplified as the exposure member. However, the present invention is not limited to this, and for example, a plurality of LEDs arranged in the left-right direction. It may be an LED head having only one row of LEDs. Further, the exposure member may be composed of one light emitting element such as an LED or a fluorescent lamp and a plurality of liquid crystal or PLZT element optical shutters arranged in the left-right direction outside the light emitting element. Further, the light source of the exposure member is not limited to the LED, but may be an EL (electroluminescence) element or a phosphor.

DESCRIPTION OF SYMBOLS 1 Color printer 10 Main body case 11 Opening part 12 Upper cover 41 LED head 41E Light emission surface 42 Support frame 42D Rotating shaft part 43 Guide roller 50 Process cartridge 53 Photosensitive drum 54 Positioning part 100 Retraction mechanism 110 Compression coil spring

Claims (5)

A main body housing provided with an opening;
A cover that is rotatably provided in the main body housing and rotates between a closed position that covers the opening and an open position that opens the opening;
A photoconductor that is rotatably provided in the main body housing and forms an electrostatic latent image;
An exposure member provided so as to be movable with respect to the cover, and exposing the photoconductor along a main scanning direction when the cover is in the closed position,
A positioning member that contacts the exposure member in the sub-scanning direction of the exposure member is provided in the main body casing,
An image forming apparatus, wherein the cover is provided with a biasing member that biases the exposure member toward the positioning member. The exposure member is provided with an interval holding member that maintains an interval between the light emitting surface of the exposure member and the surface of the photoconductor by contacting the surface of the photoconductor.
The image forming apparatus according to claim 1, wherein the urging member urges the exposure member in the same direction as a moving direction of a surface of the photoconductor facing the exposure member. The exposure member is rotatably provided on the cover,
When the cover is in the closed position, the light exit surface of the exposure member is disposed at an exposure position for exposing the photoconductor, and when the cover is in the open position, the light of the exposure member A retraction mechanism for disposing the exit surface at a retraction position closer to the cover side than the exposure position;
2. The biasing member is configured to bias the exposure member from the retracted position toward the exposure position, thereby serving also as a part of the retracting mechanism. The image forming apparatus according to 2.   4. The biasing member according to claim 1, wherein the biasing member is configured to bias a portion of the exposure member that is on the inner side of both end edges in the main scanning direction of the light emitting surface. The image forming apparatus according to claim 1. The image forming apparatus according to claim 1, wherein a plurality of the photosensitive members and the exposure members are provided so as to correspond to a plurality of colors.

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