JP2010191279A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus that can reduce color shift by accurately positioning a development unit and writing unit in replacing the development unit, achieves operability when a user replaces the development unit, and is easily cleaned when foreign objects are attached to the writing unit. <P>SOLUTION: A movable frame 14 houses: a plurality of the development unit 26 in which a drum-type photoreceptor 24 is integrated; and the writing unit 28 for scanning the drum-type photoreceptor 24 with light beam to form the electrostatic latent image. The writing unit and development unit are arranged so that the development unit lies on the upper side of the writing unit. The movable frame is slidably supported onto a body frame 12 having a front cover 18 that can be opened and closed and constitutes the casing of the image forming apparatus 10. The development unit can be replaced by opening the front cover and drawing the movable frame to the outside of the image forming apparatus. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an image forming apparatus such as a printer or a copying machine, and more particularly to an image forming apparatus that facilitates an attaching / detaching operation for replacing a developing unit.

  In an image forming apparatus such as a printer or a copying machine, an internal unit can be pulled out from the apparatus main body in order to replace an internal unit that is a consumable item or to remove a jammed paper.

  In JP-A-2008-65122, a writing unit is fixed to an upper cover so as to facilitate an attaching / detaching operation for replacing a developing unit in which a photoconductor is integrated. And a tandem type full-color image forming apparatus in which the developing unit can be pulled out upward.

  As described above, in a conventional tandem type full-color image forming apparatus, a method in which a user replaces a developing unit in which a photoreceptor is integrated is widely adopted. However, the method disclosed in Patent Document 1 has the following problems.

  Since the writing unit rotates together with the upper cover with the upper cover open, and it is necessary to attach and detach the developing unit while avoiding the writing unit, the operability by the user when the developing unit is replaced is poor.

  Also, since the development unit is replaced by fixing the writing unit to the upper cover and rotating, the degree of freedom increases in the direction of attaching and detaching the development unit. However, when the upper cover is closed after replacement of the development unit, The positioning accuracy between the embedding unit and the developing unit may deteriorate, resulting in color misalignment and the like, resulting in an image defect.

  Further, since the writing unit is fixed to the upper cover and rotates, it is difficult to clean when foreign matter adheres to the writing unit.

  Furthermore, a space for opening the upper cover above the apparatus main body is required, and there are restrictions on the installation location of the image forming apparatus.

  An object of the present invention is to accurately position the developing unit and the writing unit when replacing the developing unit to reduce color misregistration, ensure operability when the user replaces the developing unit, and the writing unit. An object of the present invention is to provide an image forming apparatus that is easy to clean even when foreign matter adheres to the surface.

  The present invention includes at least one developing unit in which a drum-shaped photoconductor is integrated, and a writing unit that scans a light beam on the drum-shaped photoconductor to form an electrostatic latent image, according to an electrophotographic process. In an image forming apparatus for forming an image on a recording medium, a main body frame that constitutes a casing of the image forming apparatus, has a front cover that can be opened and closed, is slidably supported with respect to the main body frame, and is external to the image forming apparatus. A box-shaped movable frame that can be pulled out is provided, and the writing unit and the developing unit are housed in the movable frame so that the developing unit is disposed on the writing unit.

  When the image forming apparatus is a tandem type full-color image forming apparatus, a plurality of developing units are held in tandem in a direction perpendicular to the sliding direction of the movable frame, and the writing unit is fixed to the movable frame. Each developing unit is configured to be detachable in the vertical direction with respect to the movable frame.

  If the writing unit has the light beam emission opening on the upper side, the light beam emission opening can be exposed when the developing unit is pulled upward from the movable frame.

  The movable frame has a box shape, two side plate members extending in a direction parallel to the pulling direction, two front plate members fixed to the side plate member and extending in a direction perpendicular to the pulling direction, and the rear The writing unit is positioned by the first positioning member with respect to each side plate member. It is preferable that the first positioning member includes at least one positioning hole provided in the side plate member and at least one positioning pin provided in the writing unit and fitted in the positioning hole.

  The developing unit is positioned by the second positioning member with respect to the two side plate members. The second positioning member is provided on each side plate member with a plurality of slits cut downward from the upper end, and at least two end faces in the axial direction of each developing unit, and engages with the corresponding slits. It is preferable to configure it from columnar protrusions.

  Two slide members are provided on the outer surface of each side plate member so as to protrude outwardly and are spaced apart in the pull-out direction of the movable frame, and the main body frame extends in the direction in which the movable frame is pulled out. When the movable frame is pulled out, the slide member slides on the rail.

  Each rail has a stopper portion for stopping the movement of the movable frame in the direction opposite to the pull-out direction on the upstream side of the pull-out direction of the movable frame so that the movable frame can be positioned with respect to the main body frame.

  The front cover has two rail-shaped pressing members that press the front plate member on the downstream side in the pulling direction of the movable frame in a direction opposite to the pulling direction of the movable frame. In a state where the front cover is opened and tilted in the horizontal direction and the movable frame is pulled out, the slide member on the upstream side in the pull-out direction of the movable frame is supported by the rail of the main body frame and is downstream in the pull-out direction of the movable frame. The side slide member is supported by the rail-like pressing member of the front cover. Thereby, when the movable frame is pulled out from the printer, the movable frame is stabilized in posture, and thus the operation becomes easy.

  The rail-shaped pressing member is preferably urged in a direction opposite to the pulling direction by a spring such as a coil spring.

  According to the image forming apparatus of the present invention, since the movable frame can be pulled out from the apparatus main body and only the developing unit that is a consumable can be detached from the movable frame, the operability for the user when the developing unit is replaced is improved.

  Since the writing unit and the developing unit are accommodated in the movable frame so that the developing unit is disposed on the writing unit, the writing unit is pulled out of the printer together with the developing unit. Therefore, the degree of freedom of the printer body layout is improved.

  In addition, since the positional relationship between the developing unit and the writing unit can always be maintained, color misregistration can be reduced.

  Furthermore, since the writing unit is disposed below the developing unit, the writing unit can be easily cleaned when the developing unit is removed.

1 is a cross-sectional view of an image forming apparatus according to an embodiment of the present invention. It is a perspective view which shows a movable frame. It is the schematic for showing the positional relationship of a slide member and a rail. It is a perspective view which shows a rail and a rail-shaped press member. It is a figure which shows the state which fell the front cover. It is a figure which shows the state which pulled out the movable frame.

  FIG. 1 is a side sectional view of a tandem type full color printer 10 according to an embodiment of the present invention. This printer forms a full-color image according to a general electrophotographic process.

  The printer 10 includes a main body frame 12 that forms a casing of the printer, and a movable frame 14 that is supported inside the main body frame so as to be slidable in the horizontal direction.

  Hereinafter, a direction in which the movable frame 14 is pulled out is referred to as a front direction (a direction indicated by an arrow F), and a direction opposite to the front direction is referred to as a rear direction (a direction indicated by an arrow B).

  The main body frame 12 includes a front cover 18 that is rotatably supported by a fulcrum 16 in the front direction of the printer 10 and a rear cover 22 that is rotatably supported by a fulcrum 20 in the rear direction of the printer 10. is doing. The user can open the front cover 18 and pull the movable frame 14 out of the printer 10.

  In order to form images of toner colors of yellow (Y), cyan (C), magenta (M), and black (Bk) on the movable frame 14, drum-shaped photoreceptors 24Y, 24C, 24M, An electrostatic latent image is written by scanning the development units 26Y, 26C, 26M, and 26Bk each having 24Bk integrated therein and each charged drum-shaped photoconductor with a modulated light beam corresponding to image data for each color. A writing unit 28 is provided.

  In the following description, members corresponding to colors of yellow (Y), cyan (C), magenta (M), and black (Bk) are denoted by reference symbols Y, C, M, and Bk. If there is a need for distinction, but no distinction is required, these symbols shall not be given.

  The writing unit 28 is fixed to the bottom of the movable frame 14, and the developing unit 26 is provided on the writing unit 28 so as to be detachable from the movable frame 14.

  In the developing unit 26, the charged drum-like photosensitive member 24 is scanned with the light beam from the writing unit 28, an electrostatic latent image is formed, and developed with toner of each color.

  Inside the main body frame 12, an endless intermediate transfer belt 30 is stretched between rollers 32 and 34 so as to be in contact with the drum-shaped photoreceptors 24Y, 24C, 24M, and 24Bk. Primary transfer rollers 36 </ b> Y, 36 </ b> C, 36 </ b> M, and 36 </ b> Bk are provided on the inner peripheral portion of the intermediate transfer belt 30 so as to face each photoconductor. A secondary transfer roller 38 is provided on the outer peripheral portion of the intermediate transfer belt 30 so as to face the roller 32.

  The toner image of each color on the surface of each drum-shaped photoreceptor developed with toner is transferred to the intermediate transfer belt 30 by the primary transfer rollers 36Y, 36C, 36M, and 36Bk, and each color is superimposed to form a color toner image. .

  On the other hand, below the movable frame 14, a paper feed cassette 42 that supplies paper 40 as a recording medium is disposed so as to be drawn out of the printer 10. The paper 40 placed in the paper feed cassette 42 is selectively sent out by the rotation of the pickup roller 44. The fed paper 40 is conveyed to the secondary transfer roller 38, the color toner image on the intermediate transfer belt 30 is electrostatically transferred, and sent to the fixing unit 46 provided inside the main body frame 12.

  The fixing unit 46 includes a roller with a built-in heater, and the color toner image is fixed on the paper 40 by heating. Thereafter, the paper is sent out of the printer 10 by a paper discharge roller 48.

  2 is a perspective view showing the movable frame 14, the writing unit 28 accommodated in the movable frame 14, and the developing units 26Y, 26C, 26M, and 26Bk to be accommodated in the movable frame 14. As shown in FIG.

  The movable frame 14 has a box shape, and includes a bottom plate 50, side plates 52a and 52b parallel to a direction F (front direction) to be pulled out, a front plate 54 and a rear plate 56 extending in a direction orthogonal to the direction F. Consists of The front plate 54 is located on the downstream side in the direction F, and the rear plate 56 is located on the upstream side in the direction F.

  The bottom plate 50, the front plate 54, and the rear plate 56 connect the side plate 52a and the side plate 52b. In the vicinity of the edge of each plate 50, 54, 56, there are a plurality of fixing pieces 58 bent at right angles, and each side plate 52 a, 52 b is fixed to the fixing piece 58 with a screw 60. Thereby, the space | interval of the side plate 52a and the measuring plate 52b is ensured, and the rigidity as the movable frame 14 is ensured.

  In each side plate 52a, 52b, four slits 62 are cut at equal intervals from the upper end downward. The slits 62 of the side plates 52a and 52b are formed so as to be symmetrical between the side plates 52a and 52b. Accordingly, the same side plates 52a and 52b can be used. Further, the position of each slit 62 is set so as to be positioned with respect to the writing unit 28 when the developing unit 26 is attached to the movable frame 14, as will be described later.

  On the other hand, two columnar protrusions 64 are provided on the upper and lower sides of each developing unit 26Y, 26C, 26M, and 26Bk in the axial direction (same as the axial direction of the drum-shaped photoconductor).

  The writing unit 28 is fixed on the bottom plate 50 of the movable frame 14. When the writing unit is fixed, it is necessary to position and fix the writing unit with respect to the side plates 52a and 52b. For this purpose, two positioning pins 66f and 66b are respectively provided on both side surfaces of the writing unit 28 parallel to the F direction, and the positioning holes 68f and 68b are formed in the side plates. This is done by fitting the In this case, the positioning hole 68f on the downstream side in the F direction is a round hole, and the positioning hole 68b on the upstream side in the F direction is an oblong hole. The reason why the shape of the positioning hole 68b is an ellipse is to absorb the dimensional variation in the distance between the positioning pin 66f and the positioning pin 66b.

  The writing unit 28 includes openings 70Y, 70C, 70M, and 70Bk (70Bk for emitting a light beam to the surface of each of the drum-shaped photosensitive members 24Y, 24C, 24M, and 24Bk of the developing units 26Y, 26C, 26M, and 26Bk. (Not shown). Each light beam exit opening is provided with a translucent dustproof member (not shown).

  The developing unit 26 is mounted from above by aligning with the writing unit 28. While the two cylindrical protrusions 64 of the developing unit 26 are engaged with the slits 62 cut into the side plates 52a and 52b, the developing unit 26 is developed. The unit 26 is fitted into the movable frame 14. At this time, if the width of the slit 62 and the diameter of the columnar protrusion 64 are set so as not to cause a gap, when the developing unit 26 is attached for replacement, the fixed writing unit 28 is fixed. Thus, the developing unit 26 can be accurately positioned.

  As described above, the movable frame 14 is slidable with respect to the main body frame 12. For this purpose, as shown in FIG. 2, two cylindrical slide members 72f and 72b are fixed near the lower corners of the outer surfaces of the side plates 52a and 52b of the movable frame 14, as shown in FIG. As shown in FIG. 3, two rails 74 a and 74 b for supporting the slide members 72 f and 72 b are fixed to the main body frame 12. FIG. 3 is a schematic view for illustrating the positional relationship between the slide member and the rail, and is a view of the movable frame 14 as viewed from the rear plate 56 side. The lateral width of the front plate 54 is set to be larger than the lateral width of the rear plate 56. This is because, as will be described later, it is necessary to press both end portions of the front plate 54 in the lateral direction by pressing members provided on the front cover 18 when the front cover 18 is closed.

  In the movable frame 14 in which the writing unit 28 and the developing unit 26 are accommodated, the slide members 72f and 72b on both sides are brought into contact with the rails 74a and 74b on both sides by the own weight or biasing means such as a leaf spring, respectively. The slide members 72f and 72b are held movably by sliding on the rails 74a and 74b on both sides, respectively. As shown in FIG. 1, the rails 74a and 74b are bent at right angles at the rear end portions and serve as stopper portions with which the slide member 72b comes into contact. FIG. 4 shows a perspective view of the two rails 74a and 74b. In the drawing, the stopper portions are indicated by 76a and 76b.

  The structure of the stopper portion is not limited to the above. Since it is sufficient that the movement of the movable frame 14 can be stopped, the stopper portion may be configured to abut against the edge portions of the side plates 52a and 52b.

  On the other hand, two U-shaped rail-like pressing members 78a and 78b are movably held inside the front cover 18 rotatably supported by the fulcrum 16 in the main body frame 12. As shown in FIG. 4, the rail-like pressing members 78a and 78b are provided to be separated by the same distance as the separation distance D between the rails 74a and 74b. This is because the front slide member 72f is supported when the front cover 18 is opened and the movable frame 14 is pulled out, as will be described later. The rail-shaped pressing members 78a and 78b are urged by coil springs 80a and 80b, and move in the F direction (front direction) and the B direction (rear direction) with respect to the front cover 18, but are not illustrated by a regulating means (not shown). The range of movement is limited.

  Each rail-shaped pressing member 78a, 78b is configured to be urged in the B direction by a plurality of springs 80a, 80b. When the front cover 18 is closed, the rail-like pressing members 78a and 78b press both end portions of the front plate 54 of the movable frame. As a result, the slide members 72b on both sides come into contact with the stopper portions 76a and 76b of the rails 74a and 74b, respectively. The movable frame 14 is positioned with respect to the main body frame 12. With such a simple mechanism, it is possible to avoid mistakes in mounting the movable frame to the printer body.

  The rear cover 22 rotatably supported by the fulcrum 20 in the main body frame 12 can be opened when the paper 40 is jammed, and the jammed paper can be removed.

  In the image forming apparatus 10 having the above-described configuration, when the developing unit 26 that is a consumable is replaced, the user opens the front cover 18 as shown in FIG. Rotate and tilt horizontally. At this time, the height of the support surfaces of the rail-shaped pressing members 78a and 78b is substantially the same as the height of the upper surfaces of the rails 74a and 74b by the above-described appropriate regulating means (not shown), and the rail The shape pressing members 78a and 78b are held by the front cover 18 so as not to be pushed downward.

  Next, as shown in FIG. 6, the user slides the movable frame 14 forward and pulls it out of the printer 10. At this time, the front slide member 72f protruding from both side surfaces of the movable frame 14 is on the upper surface of the rail-like pressing members 78a and 78b that are tilted in the horizontal direction, and the rear slide member 72b is on the upper surface of the rails 74a and 74b. If it is positioned, the movable frame 14 is held horizontally without dropping when it is pulled out.

  Therefore, when the user replaces the developing unit 26, the developing unit 26 accommodated in the movable frame 14 is pulled out upward as indicated by the arrow U without the movable frame 14 rattling. The developing unit can be exchanged with good operability by inserting the columnar protrusion 64 into the movable frame 14 while engaging the slit 62.

  According to the full color printer of the present embodiment, when the front cover 18 is closed, the rail-like pressing members 78a and 78b press the movable frame 14 in the direction opposite to the pull-out direction to position the movable frame 14. When the front cover 18 is opened, the movable frame 14 is supported. Thus, the number of parts can be reduced by giving the rail-like pressing member two functions.

  Further, when the developing unit is pulled upward from the movable frame, the light beam emission opening of the writing unit faces upward, so that foreign matter can be visually observed and cleaning can be performed easily. Image defects such as white stripes can be prevented by cleaning.

  Further, according to the full color printer of this embodiment, the writing unit is positioned by fitting positioning pins provided on the side portions of the writing unit into positioning holes provided on the side plate of the movable frame. . The side plate of the movable frame uses the same parts with slits, so that when a plurality of development units are set on the movable frame, the development units are arranged at equal intervals. The positional accuracy is also equally arranged on both sides of the movable frame. For this reason, when the developing unit is replaced, the positional relationship with the writing unit can be maintained with extremely high accuracy, and color misregistration can be reduced.

  The present invention has been described by taking the tandem type full color printer as an example, but it is obvious that the present invention can be applied not only to a color printer but also to a single color printer.

  Furthermore, it goes without saying that the present invention can be applied not only to printers but also to copying machines and facsimile machines.

DESCRIPTION OF SYMBOLS 10 Full color printer 12 Main body frame 14 Movable frame 18 Front cover 22 Rear cover 24 Drum-shaped photoreceptor 26 Developing unit 28 Writing unit 50, 52, 54, 56 Plate 62 Slit 64 Cylindrical protrusion 66 Pin 68 Hole 70 Opening 72 Slide Member 74 Rail 76 Stopper

JP 2008-65122 A

Claims (11)

And at least one developing unit integrated with the drum-shaped photosensitive member, and a writing unit that scans the drum-shaped photosensitive member with a light beam to form an electrostatic latent image on a recording medium according to an electrophotographic process. In an image forming apparatus for forming an image on
A main body frame that constitutes a casing of the image forming apparatus and has a front cover that can be opened and closed;
A box-shaped movable frame that is slidably supported with respect to the main body frame and can be pulled out of the image forming apparatus;
The image forming apparatus, wherein the writing unit and the developing unit are accommodated in the movable frame so that the developing unit is disposed on the writing unit. The image forming apparatus according to claim 1,
A plurality of developing units are held in tandem in a direction perpendicular to the sliding direction of the movable frame, the writing unit is fixed to the movable frame, and each developing unit is vertically positioned with respect to the movable frame. An image forming apparatus which is detachable. The image forming apparatus according to claim 1, wherein
The image forming apparatus, wherein the writing unit has a light beam emission opening corresponding to each developing unit on the upper side. The image forming apparatus according to claim 1, 2 or 3.
The movable frame includes two side plate members extending in a direction parallel to the pull-out direction, and two front plate members and a rear plate fixed to the side plate member and extending in a direction perpendicular to the pull-out direction. And having a member
The image forming apparatus, wherein the writing unit is positioned by a first positioning member with respect to each side plate member. The image forming apparatus according to claim 4.
The first positioning member includes at least one positioning hole provided in the side plate member and at least one positioning pin provided in the writing unit and fitted in the positioning hole. An image forming apparatus. The image forming apparatus according to claim 4 or 5, wherein:
The image forming apparatus, wherein the developing unit is positioned by a second positioning member with respect to the two side plate members. The image forming apparatus according to claim 6.
The second positioning member is provided on each of the side plate members with a plurality of slits cut downward from the upper end and on both end surfaces in the axial direction of each developing unit, and engages with the corresponding slit. An image forming apparatus comprising two columnar protrusions. The image forming apparatus according to claim 4,
On the outer surface of each side plate member, two slide members are provided that protrude outward and are spaced apart in the pull-out direction of the movable frame,
The main body frame is provided with two rails extending in a direction in which the movable frame is pulled out and supporting the slide members,
The image forming apparatus, wherein the slide member slides on the rail when the movable frame is pulled out. The image forming apparatus according to claim 8.
The image forming apparatus according to claim 1, wherein each of the rails has a stopper portion that stops the movement of the movable frame in a direction opposite to the pulling direction on the upstream side of the pulling direction of the movable frame. The image forming apparatus according to claim 9.
The front cover has two rail-shaped pressing members that press the front plate member on the downstream side in the pulling direction of the movable frame in a direction opposite to the pulling direction of the movable frame,
In a state where the front cover is opened and tilted in the horizontal direction and the movable frame is pulled out, a slide member on the upstream side in the pull-out direction of the movable frame is supported by a rail of the main body frame, and the movable frame The slide member on the downstream side in the pull-out direction is supported by a rail-like pressing member of the front cover. The image forming apparatus according to claim 10.
The image forming apparatus, wherein the two rail-shaped pressing members are each urged by a spring in a direction opposite to the pulling-out direction.

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