JP2008262077A - Imaging unit and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an imaging unit having a simple structure, with the unit designed so as to be correctly positioned in an image forming apparatus without requiring large force. <P>SOLUTION: The imaging unit has a photoreceptor frame 14 by which a photoreceptor 5, on the surface of which images are formed, is held rotatably; and an intermediate transfer frame 18 connected to the photoreceptor frame 14 so as to be undulatable together with the photoreceptor frame 14, and holding at least two extension rollers 15 and 16 extending a rotatable intermediate transfer belt 8, on which images are transferred from the photoreceptor 5. A primary transfer roller 7 is disposed on the photoreceptor frame 14 so as to come into contact with the inside of the intermediate transfer belt 8 and opposite to the photoreceptor 5. The photoreceptor frame 14 and the intermediate transfer frame 18 are swung and energized by the tension of the intermediate transfer belt 8 so as to draw each other. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an imaging unit and an image forming apparatus.

  In an electrophotographic image forming apparatus, a unit including a photoconductor on which an electrostatic latent image is formed, a unit for supplying a developer to the photoconductor to develop an image, and an intermediate transfer in which an image is transferred from the photoconductor A unit for holding the belt in a stretched state, a unit for secondary transfer of an image from the intermediate transfer belt to the recording paper, a unit for fixing the image by heating the recording paper, etc. are detachably held to form an image. There are many devices that can be replaced and maintained for each unit.

  In order to ensure image quality, it is necessary to accurately position each unit at a predetermined position in the image forming apparatus.

  In Patent Document 1, a unit in which a unit that holds a photoconductor and a unit that holds an intermediate transfer belt and a primary transfer roller are connected to be relatively movable is mounted on an image forming apparatus, so that the photoconductor and the intermediate transfer are mounted. An invention is described in which the position of the belt is fixed.

However, in the image forming apparatus, it is necessary to press the primary transfer roller against the photoconductor via the intermediate transfer belt, so that a reaction force from the photoconductor acts on a unit that holds the intermediate transfer belt. For this reason, the image forming apparatus needs a strong lock mechanism that can press down the unit that holds the intermediate transfer belt against the reaction force.
JP 2002-99123 A JP 2001-350392 A JP 2000-356885 A

  It is an object of the present invention to provide an imaging unit having a simple structure that can be accurately positioned and mounted on an image forming apparatus without requiring a large force.

  In order to solve the above-described problems, an imaging unit according to the present invention includes a photosensitive member frame that rotatably supports a photosensitive member having an image formed on a surface thereof, and is rotatably connected to the photosensitive member frame. An intermediate transfer frame that rotatably holds at least two stretching rollers that stretch an intermediate transfer belt to which an image is transferred from the body, and abuts the inner side of the intermediate transfer belt to the photosensitive frame, It is assumed that a primary transfer roller facing the photosensitive member is provided.

  According to this configuration, since the primary transfer roller is provided on the photoconductor frame, the reaction force of the pressure contact force between the photoconductor and the primary transfer roller does not act on the intermediate transfer frame. As a result, the photoconductor frame and the intermediate transfer frame can be accurately positioned only by pressing with a small force.

  In the imaging unit of the present invention, the intermediate transfer frame can swing with respect to the photoreceptor frame within a range in which the primary transfer roller pulls the intermediate transfer belt out of the tangent line of the stretching roller. It may be.

  According to this configuration, the photosensitive frame and the intermediate transfer frame are attracted to each other by the tension of the intermediate transfer belt, so that the photosensitive frame and the intermediate transfer frame can be pressed and positioned to a predetermined position of the image forming apparatus by this tension. .

  In the imaging unit of the present invention, the photoreceptor frame may further hold a tension roller that applies tension to the intermediate transfer belt.

  According to this configuration, the tension of the intermediate transfer belt does not change due to the relative swing of the photosensitive frame and the intermediate transfer frame, and the swing range of the photosensitive frame and the intermediate transfer frame can be increased.

  In the imaging unit of the present invention, in the intermediate transfer frame and the intermediate transfer frame, a boss provided in the other is engaged with a long hole provided in one of the intermediate transfer frame, and the boss moves along the long hole. Thus, they may be able to swing with respect to each other.

  According to this configuration, the swing range of the photoconductor frame and the intermediate transfer frame can be regulated with a simple structure.

  In the imaging unit of the present invention, the boss may be a rotating shaft of the photoconductor.

  According to this configuration, the photosensitive member can be directly positioned by positioning the boss.

  According to the present invention, the photoconductor frame, the intermediate transfer frame, and the intermediate transfer frame are attracted to each other by the tension of the intermediate transfer belt. Can be pressed to a predetermined position in the image forming apparatus.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 shows an image forming apparatus 1 according to one embodiment of the present invention. The image forming apparatus 1 includes a developing rotary unit 4 that holds a developing unit 3 that supplies cyan, magenta, yellow, and black toner in an annular shape inside a main body 2 and a rotation that can form an electrostatic latent image on the surface. An imaging unit 9 that holds an intermediate transfer belt 8 to which an image formed on the photoreceptor 5 is transferred by a possible photoreceptor 5, a charger 6 that charges the photoreceptor 5, a primary transfer roller 7, and a primary transfer roller 7 An exposure unit 10 that exposes the photosensitive member 5, a two-transfer roller 11, a fixing unit 12, and a paper feed unit 13 are provided.

  The imaging unit 9 includes a photoreceptor frame 14 that holds the photoreceptor 5, the charger 6, and the primary transfer roller 7, an intermediate transfer belt that holds the tension rollers 15 and 16 and the tension roller 17 that stretch the intermediate transfer belt 8. Frame 18. The photoconductor 5 is located outside the intermediate transfer belt 8, the primary transfer roller 7 is in contact with the inside of the intermediate transfer belt 8, and the photoconductor 5 and the primary transfer roller 7 are connected via the intermediate transfer belt 8. It is held so as to face each other.

  The imaging unit 9 can be attached to and detached from the image forming apparatus 1 by opening the lid 19 of the main body 2, and the stretch roller 15 is attached to the two transfer rollers 11 via the intermediate transfer belt 8 in the mounted state. It comes to be pressed.

  As shown in detail in FIG. 2, the intermediate transfer frame 18 has elongated holes 20 and 21 formed therein. A swing boss 22 that is an end of the rotating shaft of the photoconductor 5 protruding from the photoconductor frame 14 is engaged with the elongated hole 20, and a swing boss 23 that protrudes from the photoconductor frame is engaged with the long hole 21. Are engaged. The photoconductor frame 14 and the intermediate transfer frame 18 can swing with respect to each other within a range in which the swing bosses 22 and 23 can move along the long holes 20 and 21.

  In the swinging range of the photoconductor frame 14 and the intermediate transfer frame 18, the primary transfer roller 7 does not completely enter between the stretching rollers 15 and 16, and the intermediate transfer belt 8 is moved between the stretching rollers 15 and 16. Located so as to be pulled out of the tangent line.

  Further, a rotation stop boss 24 protrudes from the photoconductor frame 14, and the intermediate transfer frame 18 has a rotation stop boss 25 and a positioning boss 26 from which the rotation shafts of the stretching rollers 15 and 16 protrude.

  The positioning boss 26 is received by a positioning bush 27 formed on the main body 2, and is accurately positioned by a pressing lever 28 provided by spring-biasing the lid 19. Similarly, a pressing lever 29 provided by spring biasing the lid 19 presses the swing boss 22 to rotate the imaging unit 9 around the positioning boss 26, but the positioning boss 24 of the photoconductor frame 14. However, it abuts against a regulating portion 30 formed on the main body 2 to regulate the swinging of the photoconductor frame 14.

  Since the intermediate transfer belt 8 stretched around the stretching rollers 15 and 16 of the intermediate transfer frame 18 is tensioned by the tension roller 17, it is arranged inside so as to extend straight between the stretching rollers 15 and 16. The primary transfer roller 7 is pulled in. Since the photoreceptor frame 14 holding the primary transfer roller 7 is positioned by being pressed by the pressing lever 29, the tension of the intermediate transfer belt 8 causes the photoreceptor to move around the intermediate transfer frame 18 around the positioning boss 26. It will be turned toward 5. Then, the boss 24 comes into contact with the regulating portion 31 provided on the main body 2 and the position and posture of the intermediate transfer frame 18 are determined.

  As described above, in the present invention, the photosensitive frame 14 and the intermediate transfer frame 18 are swung so as to be attracted to each other by the tension of the intermediate transfer belt 8. 2, the intermediate transfer frame 18 is positioned so that the intermediate transfer frame 18 can be positioned by being pushed into the main body 2.

  In the present invention, since the photoconductor 5 and the primary transfer roller 7 are held on the same photoconductor frame 14, the pressing force between the photoconductor 5 and the primary transfer roller 7 pushes out the intermediate transfer frame 18. Therefore, it is not necessary to hold down the imaging unit 9 with a large force. For this reason, the load applied to the holding levers 28 and 29 provided on the lid 19 is small. Therefore, strength is not required for the main body 2 and the lid 19 of the image forming apparatus 1, and an inexpensive structure can be achieved.

  In the imaging unit 9 of the present invention, the long holes 20 and 21 are formed in the intermediate transfer frame 18, and the swing bosses 22 and 23 that are engaged with the long holes 20 and 21 are protruded from the photoconductor frame 14. Simple connection structure. For this reason, the imaging unit 9 itself can also be provided at low cost.

1 is a schematic view of an image forming apparatus according to an embodiment of the present invention. The enlarged view of the imaging unit of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Image forming apparatus 5 Photoconductor 7 Primary transfer roller 8 Intermediate transfer belt 9 Imaging unit 14 Photoconductor frame 15, 16 Stretching roller 17 Tension roller 18 Intermediate transfer frame 20 Long hole 21 Long hole 22 Swing boss 23 Swing boss 23 24 Rotation Stop Boss 25 Rotation Stop Boss 26 Positioning Boss 27 Positioning Bush 28 Pressing Lever 29 Pressing Lever 30 Restricting Part 31 Restricting Part

Claims (6)

A photoreceptor frame that rotatably holds a photoreceptor on which an image is formed;
An intermediate transfer frame rotatably connected to the photoconductor frame and rotatably holding at least two tension rollers that stretch an intermediate transfer belt on which an image is transferred from the photoconductor;
An imaging unit, wherein a primary transfer roller that contacts the inner side of the intermediate transfer belt and faces the photosensitive member is provided on the photosensitive member frame.   The intermediate transfer frame is swingable with respect to the photoreceptor frame within a range in which the primary transfer roller pulls the intermediate transfer belt out of a tangent line of the stretching roller. The imaging unit according to 1.   The imaging unit according to claim 1, wherein the photosensitive frame further holds a tension roller that applies tension to the intermediate transfer belt.   The intermediate transfer frame and the intermediate transfer frame can swing with respect to each other by engaging a boss provided in the other with a slot provided in one of the intermediate transfer frame and moving along the slot. The imaging unit according to claim 1, wherein:   The imaging unit according to claim 4, wherein the boss is a rotating shaft of the photoconductor.   An image forming apparatus comprising the imaging unit according to claim 1.

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