JP2008003340A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus achieving the enhancement of workability when attaching a drum unit equipped with a photoreceptor drum and an electrifying roller. <P>SOLUTION: The image forming apparatus X is equipped with an upper rail 21 indirectly guiding the rotary shaft of the electrifying roller 12 from the attaching position of the drum unit D to the image forming apparatus X to the take-out position of the drum unit D, and a lower rail 22 guiding the rotary shaft 11-1 of the photoreceptor drum 11. The upper rail 21 and the lower rail 22 are provided to leave space where the electrifying roller 12 and the photoreceptor drum 11 abut on each other at the attaching position, and provided to leave space where the electrifying roller 12 and the photoreceptor drum 11 are separated from each other at the take-out position. When the drum unit D is at the take-out position, the electrifying roller 12 and the photoreceptor drum 11 are maintained in the separated state. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an image forming apparatus, and more particularly to an image forming apparatus in which an image forming unit including an image carrier and a charging roller is detachable.

Conventionally, when performing maintenance of the unit in an image forming apparatus having a unit having a photosensitive drum and a charging roller, the unit is removed from the image forming apparatus main body and the maintenance is performed. In that case, in order to clean the charging roller in the removed unit, there is a risk of damage due to collision if the charging roller and the photosensitive drum are kept in contact with each other. The charging roller needs to be separated.
In the image forming apparatus described in Patent Document 1, an urging unit that constantly urges the charging roller in a direction in which the charging roller is separated from the photosensitive drum is provided, and a unit including the charging roller and the photosensitive drum. In the state where the image forming apparatus body is mounted, the urging force of the urging means is suppressed by the housing, and the charging roller and the photosensitive drum are in contact with each other. On the other hand, in a state where the unit is detached from the image forming apparatus main body, the pressing force by the casing that suppresses the urging force of the urging means is released, so that the charging force is applied by the urging force of the urging means. A roller is separated from the photosensitive drum.
As described above, the unit is removed from the main body of the image forming apparatus, and the charging roller is pulled out in the longitudinal direction by an operator in a state where the photosensitive drum and the charging roller are separated from each other. The surface of the charging roller is cleaned.
JP-A-5-107881

However, in the configuration in which the photosensitive drum and the charging roller are separated from each other as in the image forming apparatus described in Patent Document 1, when the unit is mounted on the main body of the image forming apparatus, the urging means is always charged. Since the roller acts in a direction to move away from the photosensitive drum, the unit is moved to the image while pressing the photosensitive drum and the charging roller in a direction against the urging force of the urging means. It was difficult to work because it had to be attached to the main body of the forming device.
Accordingly, the present invention has been made in view of the above circumstances, and an object thereof is to provide an image forming apparatus that improves workability when a drum unit including a photosensitive drum and a charging roller is mounted. .

As described above, a rotatable image carrier that bears an electrostatic latent image developed by a developer, and a charging roller that is detachable while maintaining a parallel state with the image carrier, are provided by an urging unit. In a conventional image forming apparatus in which the image carrier and the charging roller are separated only by an urging force, the image forming unit is pressed while pressing the image carrier and the charging roller against the urging force. The unit had to be mounted on the main body of the image forming apparatus, which was difficult to work with.
Therefore, in the present invention, the first and second guides that directly or indirectly guide the rotation shafts of the charging roller and the image carrier from the mounting position of the image forming unit to the image forming apparatus to the take-out position of the image forming unit, respectively. A rail and a separation maintaining means for maintaining the charging roller and the image carrier in a separated state when the image forming unit is in the take-out position, and the first rail and the second rail. When the image forming unit is in the mounting position, a rail is provided at an interval where the charging roller and the image carrier are in contact with each other. When the image forming unit is in the take-out position, The charging roller and the image carrier are provided at a distance from each other.
Thus, the image forming unit can be removed from the image forming apparatus main body without performing difficult work such as mounting while pressing a part of the image forming unit against the urging force of the urging means. The image carrier and the charging roller are separated from each other, and the image carrier and the charging roller are brought into contact with each other only by mounting the image forming unit on the main body of the image forming apparatus.
In addition, the image bearing member and / or the charging roller is provided with guide means for slidably guiding the image bearing member and the charging roller in a direction in which the image bearing member and the charging roller are separated from each other. It is conceivable that the urging means urges the body and the charging roller away from each other.
On the other hand, the image forming unit has a first protrusion for indirectly guiding the charging roller to the first rail and / or a second for indirectly guiding the image carrier to the second rail. It is conceivable to provide a protrusion.
This is because the first and second rails indirectly guide the rotation shafts of the charging roller and the image carrier from the mounting position of the image forming unit to the image forming apparatus to the take-out position of the image forming unit, respectively. It is an example.
In addition, the annular portion of the elastic member that is slidable in contact with the outer periphery of the charging roller and the image bearing member and the charging roller are separated from each other by the separation maintaining means. A support portion that is movably supported in the rotation axis direction of the roller, and the interval between the first rail and the second rail at the take-out position is such that the annular portion rotates along the charging roller. It is preferable that the interval be movable in the axial direction.
As a result, the annular portion can be slid along the charging roller in the rotational axis direction at the take-out position without completely removing the image forming unit from the image forming apparatus main body. The charging roller can be cleaned by sliding the part.

  According to the present invention, it is possible to provide an image forming apparatus that improves workability when a drum unit including a photosensitive drum and a charging roller is mounted.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings so that the present invention can be understood. The following embodiment is an example embodying the present invention, and does not limit the technical scope of the present invention.
1 is a cross-sectional view of the image forming apparatus X according to the embodiment of the present invention. FIG. 2 is a perspective view of the image forming apparatus X according to the embodiment of the present invention with the side cover and the developing unit 2 removed. 3 is a perspective view of the drum unit D as viewed from the direction of the arrow P7 in FIG. 1 when mounted on the image forming apparatus X according to the embodiment of the present invention. FIG. 4 is a schematic view of the drum unit D with the side support member 14 removed. FIGS. 5A and 5B show that the rotating shaft 11-1 of the photosensitive drum 11 and the protrusions 14-2 and 14-3 of the drum unit D of the image forming apparatus X according to the embodiment of the present invention are formed on the upper rail 21 and the lower rail 22, respectively. FIG. 6 is a schematic diagram for explaining a guided route. FIG. 6 is a schematic diagram of the vicinity of the rotating shaft 11-1 of the photosensitive drum 11 and the protrusions 14-2 and 14-3 of the drum unit D as viewed from the P direction of FIG. 7 shows the annular portion 16 and the support. Schematic of 17, 8 is an enlarged view of the vicinity support 17, FIG. 9 is a perspective view of the drum unit D in the image forming apparatus drum unit D unloading position of X according to the embodiment of the present invention.
In the schematic diagram of FIG. 4, the side support member 14 of the drum unit D is removed from the drum unit D for explanation.

As shown in FIG. 1, the image forming apparatus X according to the embodiment of the present invention is roughly classified into an image forming unit G that forms (transfers) a toner image on a recording sheet, and a recording sheet that is placed on the image forming unit G. The sheet feeding unit K to be supplied, the fixing unit T that heat-fixes the toner image on the recording paper on which the toner image is formed by the image forming unit G, and the casing 20 (see FIG. 2) that accommodates the toner image. Has been.
As shown in FIG. 1, the image forming unit G includes a drum unit D (an example of an image forming unit), an exposure unit 1, a developing unit 2, a transfer unit 3, a cleaning unit (not shown), a charge eliminating unit (not shown), and the like. Configured.
The drum unit D includes a photosensitive drum 11, a charging roller 12, an upper support member 13, a side support member 14, and a charging roller housing portion 15 as shown in FIG. 3 which is a schematic view seen from the direction of arrow P7 in FIG. , An annular portion 16 (described later), a support portion 17 (described later), a biasing portion 18 (see FIG. 4), and the like. The drum unit D can be attached to and detached from the image forming apparatus X main body. Details of the attachment / detachment of the drum unit D will be described later.
When the drum unit D is in the mounting position (the position shown in FIG. 1) with respect to the image forming apparatus X, the photosensitive drum 11 contacts the charging roller 12 and is centered on the rotating shaft 11-1. , Which rotates in a predetermined direction and carries an electrostatic latent image, and is separated from the charging roller 12 when the drum unit D is in the take-out position with respect to the image forming apparatus X.
The photosensitive drum 11 corresponds to an example of an image carrier.
The charging roller 12 is detachable from the photosensitive drum 11 while maintaining a parallel state. That is, when the drum unit D is in the mounting position (position shown in FIG. 1) with respect to the image forming apparatus X, the charging roller 12 rotates in contact with the photosensitive drum 11 and rotates. The surface of the drum 11 is charged. When the drum unit D is at the take-out position with respect to the image forming apparatus X, the photosensitive drum 11 is pushed away from the charging roller 12 by being pushed by the urging unit 18, so that the photosensitive drum 11 apart.
The upper support member 13 supports the charging roller housing portion 15 that supports the charging roller 12 and the side support member 14 that supports the photosensitive drum 11.
The charging roller housing portion 15 is a member that supports both ends of the rotating shaft of the charging roller 12.
As shown in FIG. 4, the side support member 14 is formed with a long hole 14-1 and protrusions 14-2 and 14-3.
The long hole 14-1 is a hole into which the rotating shaft 11-1 of the photosensitive drum 11 is fitted. The rotating shaft 11-1 of the photosensitive drum 11 is connected to the photosensitive drum 11 and the charging roller. 12 is guided so as to be slidable in the direction in which it is separated from and contacting 12 (the directions of arrows P6 and P5 in FIG. 4).
The long hole 14-1 corresponds to an example of a guide means.
The protrusions 14-2 and 14-3 are protrusions that indirectly guide the charging roller 12 to the upper rail 21 described later.
The protrusions 14-2 and 14-3 correspond to an example of a first protrusion.
A pair of the side support members 14 are provided on the left and right sides, and are fixed to the side surfaces of the drum unit D, respectively.
As shown in FIG. 4, the urging unit 18 is a spring that urges the rotating shaft 11-1 in a direction (in the direction of arrow P6 in FIG. 4) in which the photosensitive drum 11 is separated from the charging roller 12. The charging roller housing portion 15 is provided at both ends.
The urging unit 18 corresponds to an example of an urging unit.
The urging portion 18 is an example of a separation maintaining means.
In this embodiment, the urging portion 18 is provided. However, the urging portion 18 is not provided, and the charging roller 12 and the photosensitive drum 11 are maintained in a separated state. A member for hooking the photosensitive drum 11 to the side support member 14 of the drum unit D or the like may be provided.

As shown in FIG. 1, the exposure unit 1 forms an electrostatic latent image by irradiating the photosensitive drum 11 with a laser beam.
The developing unit 2 forms toner images on the surface of the photosensitive drum 11 by attaching toner to the electrostatic latent image formed on the photosensitive drum 11.
The transfer unit 3 transfers an image developed on the photosensitive drum 11 onto a recording paper or the like.
The cleaning unit cleans the photosensitive drum 11 after transfer.
The charge eliminating portion removes a potential remaining on the photosensitive drum 11 after transfer.

An image forming process performed by the image forming apparatus X will be briefly described.
When an image information signal is transmitted from a predetermined reading device or the like, the recording paper stored by the paper supply unit K is supplied to the image formation start position.
An image information signal transmitted from a predetermined reading device (not shown) or the like is transmitted to the image forming device X and subjected to predetermined image processing. Data (image data) that has undergone predetermined image processing is input to the exposure unit 1. Thereafter, the exposure unit 1 emits a laser beam (laser beam for writing an electrostatic latent image) whose light amount and blinking state are adjusted according to the data subjected to the predetermined image processing to the surface of the photosensitive drum 11. The
Then, an electrostatic latent image is written on the surface of the photosensitive drum 11 charged by the charging roller 12. The photosensitive drum 11 is rotated, and the toner carried on the developing roller of the developing unit 2 is transferred to the electrostatic latent image on the surface of the photosensitive drum 11 to form a toner image.
The photosensitive drum 11 is continuously rotated, and the toner image formed on the photosensitive drum 11 is transferred onto the recording paper conveyed by the paper feeding unit K by the transfer unit 3. The toner image transferred onto the recording paper is heated by the fixing unit T and fixed on the recording paper. The recording paper on which the toner image is fixed is discharged out of the image forming apparatus X.

By the way, in the image forming apparatus X to which the drum unit D can be attached and detached as described above, when performing maintenance of the drum unit D, the charging roller 12 and the above-described cleaning device are used to clean the charging roller 12 in the removed drum unit D. Although it is necessary to separate the photosensitive drum 11, the conventional image forming apparatus includes an urging unit that forcibly separates the charging roller and the photosensitive drum. When the photosensitive drum is brought into contact with the image forming apparatus, the image forming unit must be mounted on the main body of the image forming apparatus against the urging force of the urging means, and the operation is difficult.
In order to solve such a problem, in the present embodiment, a rail for guiding the drum unit D is provided, so that the image forming apparatus X main body can be attached to and detached from the photosensitive drum 11 along the rail. An image forming apparatus X in which the charging roller 12 is in contact with or separated from the charging roller 12 is provided.
Details are described below.

As shown in FIG. 2, an upper rail 21 and a lower rail 22 are formed on the side surfaces of the housing 20 at both ends of the photosensitive drum 11 in the rotation axis direction.
As shown in FIG. 5, the upper rail 21 has the protrusions 14-3 and 14-2 formed on the side support member 14 fitted therein so that the drum unit D with respect to the image forming apparatus X is connected to the upper rail 21. The groove portion guides from the mounting position to the take-out position of the drum unit D. By moving the protrusions 14-3 and 14-2 along the upper rail 21, the entire drum unit D integrally including the charging roller 12 is moved.
The protrusions 14-2 and 14-3 of the side support member 14 are arranged so that the rotating shaft of the charging roller 12 is placed on the upper rail 21 from the mounting position of the drum unit X to the image forming apparatus X. This is an example of a configuration that indirectly guides to the take-out position of X, and may be a configuration in which the rotation shaft of the charging roller 12 is protruded and the rotation shaft of the charging roller 12 is directly guided to the upper rail 21. .
The upper rail 21 corresponds to an example of the first rail.
As shown in FIG. 6, the lower rail 22 is fitted with a rotating shaft 11-1 of the photosensitive drum 11 fitted in a long hole 14-1 formed in the side support member 14. It is a groove that guides from the mounting position of the drum unit D to the image forming apparatus X to the take-out position of the drum unit D. As the rotating shaft 11-1 is moved along the lower rail 22, the drum unit D having the photosensitive drum 11 is moved.
In this example, the lower rail 22 directly guides the rotating shaft 11-1, but the rotating shaft 11-1 of the photosensitive drum 11 is not projected without protruding the rotating shaft 11-1 of the photosensitive drum 11. The protrusion may support the rotating shaft 11-1 of the photosensitive drum 11 from the mounting position to the take-out position on the lower rail 22 indirectly. .
Here, the lower rail 22 corresponds to an example of the second rail.
As shown in FIGS. 2 and 5, the distance between the upper rail 21 and the lower rail 22 gradually increases from the mounting position toward the take-out position.
At this time, the interval between the upper rail 21 and the lower rail 22 is an interval at which the charging roller 12 and the photosensitive drum 11 abut at the mounting position shown in FIG.
On the other hand, at the take-out position of the drum unit D, the interval between the upper rail 21 and the lower rail 22 is an interval at which the charging roller 12 and the photosensitive drum 11 are separated from each other.
Accordingly, when the drum unit D is in the mounting position shown in FIG. 1, the charging roller 12 and the photosensitive drum 11 come into contact with each other because the distance between the upper rail 21 and the lower rail 22 is narrow. When D moves to the take-out position, the charging roller 12 and the photosensitive drum 11 are separated by the widening of the space between the upper rail 21 and the lower rail 22. Details will be described later.
That is, the upper rail 21 and the lower rail 22 correspond to an example of a separation maintaining means.

Next, the movement of each part associated with the operation of attaching and detaching the drum unit D from the image forming apparatus X main body will be described. The drum unit D is attached or detached with the developing unit 2 removed.
First, in a state where the drum unit D is mounted on the main body of the image forming apparatus X, the protrusions 14-2 and 14-3 of the drum unit D and the rotating shaft 11-1 of the photosensitive drum 11 are shown in FIG. In position.
The drum unit D is moved by the operator in the direction in which the drum unit D is removed (in the direction of arrow P1 in FIG. 5). At this time, the protrusions 14-2 and 14-3 are guided to the upper rail 21. The rotating shaft 11-1 is slid to the end of the long hole 14-1 in the direction of arrow P6 in FIG. 6 by being guided by the lower rail 22. Accordingly, the photosensitive drum 11 is separated from the charging roller 12 at the take-out position of the drum unit D with respect to the image forming apparatus X (see FIG. 9).
Further, after the drum unit D is removed from the main body of the image forming apparatus X, the suppression of the urging force by the upper rail 21 and the lower rail 22 is released, so that the urging force of the urging portion 18 The state where the charging roller 12 and the photosensitive drum 11 are separated from each other is maintained.

On the other hand, in order to mount the drum unit D on the main body of the image forming apparatus X, an operator inserts the protrusions 14-2 and 14-3 into the upper rail 21 and the rotating shaft 11 into the lower rail 22. -1 is inserted. Subsequently, the drum unit D is moved by the operator in the direction in which the drum unit D is mounted (the direction of the arrow P2 in FIG. 5). At this time, the protrusions 14-2 and 14-3 are guided to the upper rail 21. The rotating shaft 11-1 slides by being guided by the lower rail 22 and is pressed against the end of the long hole 14-1 in the direction of arrow P5 in FIG. Is suppressed. Thereby, when the drum unit D is mounted, the photosensitive drum 11 is pressed against the charging roller 12, and the charging roller 12 and the photosensitive drum 11 come into contact with each other.
In the present embodiment, the developing unit 2 and the drum unit D are configured separately, but may be integrated.

Thus, the photosensitive drum 11 and the charging roller 12 are separated from each other only by moving the drum unit D to the take-out position. Even after the drum unit D is removed from the main body of the image forming apparatus X, the photosensitive drum 11 is kept away from the charging roller 12 by the urging force of the urging unit 18.
Further, when the drum unit D is mounted, the drum unit D can be easily mounted on the main body of the image forming apparatus X without performing a difficult operation such as mounting a part of the drum unit D while pressing it. The photosensitive drum 11 and the charging roller 12 are brought into contact with each other only by being mounted on the image forming apparatus X main body.
Thereby, the workability at the time of mounting the drum unit D including the photosensitive drum 11 and the charging roller 12 can be improved.

As described above, the contact portion between the charging roller 12 and the photosensitive drum 11 is cleaned while the charging roller 12 and the photosensitive drum 11 are separated from each other. In order to clean the charging roller 12, an annular portion 16 is provided that can slide the charging roller 12 in a state where the charging roller 12 and the photosensitive drum 11 are separated from each other.
The distance between the upper rail 21 and the lower rail 22 is such that the photosensitive drum 11 and the charging roller 12 are separated so that the annular portion 16 can slide while contacting the outer periphery of the charging roller 12. If the interval is set, the annular portion 16 can move along the charging roller 12 in the direction of the rotation axis at the take-out position without completely removing the drum unit D from the main body of the image forming apparatus X. Therefore, the charging roller 12 can be cleaned by sliding the annular portion 16.
Here, the annular portion 16 is an annular member that is slidable in contact with the outer periphery of the charging roller 12. As shown in FIG. 7B, the inner side of the annular portion 16 is formed of an elastic member such as acrylic pile or urethane foam. The charging roller 12 is inserted into the hole of the annular portion 16.
The annular portion 16 is not limited to this shape, and may be any shape as long as it can slide on the outer periphery in contact with the charging roller 12 and perform cleaning.
As shown in FIG. 7A, the support portion 17 is a handle for supporting the annular portion 16 and moving the annular portion 16, and is a center smaller than the width of the groove portion of the charging roller housing portion 15. A portion 17-1 and a handle portion 17-2 provided at the upper portion of the central portion 17-1 and larger than the width of the groove portion are provided. The central portion 17-1 is fitted in a groove portion provided along the charging roller 12 of the charging roller housing portion 15. With such a configuration, the support portion 17 moves only in the direction of the rotation axis of the charging roller 12 on the charging roller housing portion 15 in a state where the photosensitive drum 11 and the charging roller 12 are separated from each other. The support member is capable of moving the annular portion 16 in the direction of the rotation axis of the charging roller 12.
Incidentally, a flange portion 11-2 is formed at the end portion of the photosensitive drum 11. When the photosensitive drum 11 is in contact with the charging roller 12, the side end of the flange portion 11-2 is in contact with the annular portion 16, as shown in FIG. Therefore, when the photosensitive drum 11 and the charging roller 12 are in contact, the annular portion 16 cannot be moved in the direction of the rotation axis of the charging roller 12.
On the other hand, when the photosensitive drum 11 and the charging roller 12 are separated from each other, the flange portion 11-2 does not contact the annular portion 16 as shown in FIG. The support portion 17 can move the charging roller 12 in the rotational axis direction (directions of arrows P3 and P4 in FIG. 8).
The support portion 17 is not limited to this shape, and may have any shape as long as the annular portion 16 is moved in the rotation axis direction of the charging roller 12.

1 is a cross-sectional view of an image forming apparatus X according to an embodiment of the present invention. 3 is a perspective view of the image forming apparatus X according to the embodiment of the present invention with a side cover and a developing unit 2 removed. FIG. 1 is a perspective view of a drum unit D as viewed from the direction of arrow P7 in FIG. 1 when mounted on an image forming apparatus X according to an embodiment of the present invention. The schematic diagram which removed the side surface supporting member 14 from the drum unit D. FIG. The path through which the rotating shaft 11-1 of the photosensitive drum 11 and the protrusions 14-2 and 14-3 of the drum unit D of the image forming apparatus X according to the embodiment of the present invention are guided by the upper rail 21 and the lower rail 22 is illustrated. The schematic diagram for demonstrating. FIG. 4 is a schematic diagram of the vicinity of the rotating shaft 11-1 of the photosensitive drum 11 and the protrusions 14-2 and 14-3 of the drum unit D as viewed from the P direction of FIG. The schematic diagram of the annular part 16 and the support part 17. FIG. The enlarged view of the support part 17 vicinity. FIG. 3 is a perspective view of the drum unit D at the drum unit D take-out position of the image forming apparatus X according to the embodiment of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Exposure part 2 ... Developing part 3 ... Transfer part 11 ... Photoconductor drum 11-1 ... Rotating shaft 11-2 ... Flange part 12 ... Charging roller 13 ... Upper support member 14 ... Side part support member 14-1 ... Long hole 14-2, 14-3 ... Projection portion 15 ... Charging roller housing portion 16 ... Ring portion 17 ... Support portion 18 ... Energizing portion 20 ... Housing 21 ... Upper rail 22 ... Lower rail

Claims (5)

A detachable image forming unit comprising a rotatable image carrier that carries an electrostatic latent image developed by a developer, and a charging roller that is detachable from the image carrier while maintaining a parallel state. An image forming apparatus comprising:
First and second rails for directly or indirectly guiding the rotation shafts of the charging roller and the image carrier from the mounting position of the image forming unit to the image forming apparatus to the take-out position of the image forming unit, respectively;
A separation maintaining means for maintaining the charging roller and the image carrier in a separated state when the image forming unit is in the take-out position;
The first rail and the second rail are provided at an interval where the charging roller and the image carrier are in contact with each other when the image forming unit is in the mounting position. An image forming apparatus, wherein the charging roller and the image carrier are spaced apart from each other when the toner is at the take-out position. A guide means for slidably guiding the image carrier and / or the charging roller in a direction in which the image carrier and the charging roller are separated from and contacting each other;
The image forming apparatus according to claim 1, wherein the separation maintaining unit is a biasing unit that biases the image carrier and the charging roller in a separating direction.   The image forming unit has a first protrusion that indirectly guides the charging roller to the first rail and / or a second protrusion that indirectly guides the image carrier to the second rail. The image forming apparatus according to claim 1, further comprising: An annular portion of an elastic member slidable in contact with the outer periphery of the charging roller;
A support portion for supporting the annular portion movably in the direction of the rotation axis of the charging roller in a state where the image carrier and the charging roller are separated from each other by the separation maintaining means;
The image forming apparatus according to claim 1, further comprising:   5. The image according to claim 4, wherein an interval between the first rail and the second rail at the take-out position is an interval that allows the annular portion to move along the charging roller in the rotation axis direction. Forming equipment.

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