JPH08314340A - Image forming device - Google Patents

Abstract

PURPOSE: To restrain the soiling of a discharging light emitting device, also, to simplify a photoreceptor cartridge unit and to facilitate the attaching/ detaching operation of the unit. CONSTITUTION: The device is provided with the light emitting device 20 for irradiating a photoreceptor 1 with light and attaching/detaching mechanisms 13 to 15 and 31 for driving the light emitting device 20 from a light irradiation position near the photoreceptor 1 to a retreat position far from the photoreceptor 1, or reversely driving the device 20. And also, the device is provided with the attaching/detaching mechanisms 13 to 15 including a lever member 13 for driving an electrostatic charger 2 from the retreat position far from the photoreceptor 1 to an electrostatic charging position near the photoreceptor 1, and the light emitting device 20 supported by the lever member 13 and which is moved from the retreat position far from the photoreceptor 1 to the light irradiation position near the photoreceptor 1 when the electrostatic charger 2 is driven by the lever member 13 from the retreat position far from the photoreceptor 1 to the electrostatic charging position near the photoreceptor 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic system in which a photoconductor is charged, the charged surface is exposed to image light to form an electrostatic latent image, and the electrostatic latent image is visualized by a developing device. Image forming apparatus. This type of image forming apparatus is used, for example, in copying machines, facsimiles, printers, and the like.

[0002]

2. Description of the Related Art In an electrophotographic image forming apparatus,
Immediately before or after the formation of an electrostatic latent image, an erase light emitter (including a light emitting element such as a light emitting diode) that irradiates light to the outside of the original image area of the photoconductor to eliminate the charge, and is formed by development. The light-eliminating light emitter for irradiating the developed image (toner image) with light to reduce the electrostatic attraction of the developed image to the photoconductor, and the residual toner on the surface of the photoconductor after the transfer of the developed image to the transfer paper. A light-eliminating light emitting device that reduces the electrostatic attraction force to the photoconductor, and
One or more kinds of light emitters for erasing, etc., which irradiate light on the surface of the photoreceptor that has been cleaned to remove residual toner to erase residual charges, are provided.

[0003]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention
The light emitting unit (LED) and the electric circuit board are attached to a holding member such as a metal plate, and the holding member is attached to the main body of the apparatus, resulting in an increase in cost. Further, conventionally, the photoconductor has always been installed at a constant position where the charge is removed. As a result, toner scattering from the development may contaminate the light emitting device and reduce the effect of static elimination. That is, since the distance from the photoconductor is short, the toner easily becomes soiled, and if soiled by the toner, light irradiation becomes uneven, and desired charge removal cannot be realized. Further, recently, when a photoreceptor and other image forming process elements as required are used as a cartridge unit, for example, when the image formation of a predetermined number or more is performed, the cartridge is replaced,
The process elements are easily updated to those that do not deteriorate. The above-mentioned light emitter is an element outside the cartridge unit, and is permanently installed on the main body side where the cartridge unit is attached and detached. Therefore, the light emitter does not hit the cartridge when it is attached to the main body, A cavity is required to receive the light emitter so that the light emitter is located in the immediate vicinity, and this air gap is a long slit parallel to the photoconductor and extending in the axial direction thereof, which complicates the structure of the cartridge.

A first object of the present invention is to suppress the contamination of the light emitter, and a second object thereof is to simplify the cartridge unit and facilitate the attachment / detachment operation.

[0005]

The image forming apparatus of the present invention comprises a photoconductor (1), a charging device (2) for charging the photoconductor, and an exposure means (DSR) for exposing the charged surface of the photoconductor to image light. In an image forming apparatus equipped with a developing device (3) that visualizes the electrostatic latent image generated by exposure and a transfer means (8) that transfers the visualized image of the photoconductor onto a transfer paper, the photoconductor (1) is exposed to light. A light emitting device (20) for irradiating the light source and a contacting / separating mechanism (13 to 16, 31) for driving the light emitting device from a light irradiation position near the photoconductor to a retracted position far from the photoconductor and vice versa. The first feature is that the contact / separation mechanism (13 to 16, 31) includes a lever member (13) for driving the charging device (2) from a retracted position far from the photoconductor (1) to a charging position close to the photoconductor. ), And when the charging device (2) is supported by the lever member (13) and drives the charging device (2) from a retracted position far from the photoconductor to a charging position close to the photoconductor, Emitter that moves from the retracted position to the light irradiation position close to the photosensitive member (2
The second feature is that (0), is provided.

In order to facilitate understanding, the symbols of the corresponding elements in the embodiments shown in the drawings and described later are added in parentheses for reference.

[0007]

[Operation and Effect] According to the first feature, the contact / separation mechanism
By driving the light emitter (20) to a light irradiation position close to the photoconductor (1) via (13 to 16,31), the light emitter (20) emits light to the photoconductor (1) as in the conventional case. Can be done. When light irradiation is not required, the light emitting device is attached via the contact / separation mechanism (13 to 16, 31).
(20) can be placed in a retracted position farther than the photoconductor (1),
At the retracted position, the light emitter (20) is located at a long distance from the photoconductor (1), so that the light emitter (20) is less contaminated by toner. Further, when the photoconductor and other image forming process elements are used as the cartridge unit, the light emitting device (20) is in the retracted position when the cartridge unit is attached and detached, so that the structure for attaching and detaching the cartridge unit is provided. The degree of freedom is increased, the cartridge unit can be simplified, and the attachment / detachment operation can be simplified.

According to the second feature, in addition to the same operation and effect of the first feature, the light emitter (20) moves from the retracted position to the light irradiation position. The charging device (2) also moves from the retracted position to the charging position. Therefore, the charging device (2) is also less soiled by toner. Further, when the photoreceptor and other image forming process elements are used as the cartridge unit, the charging device can be added to the cartridge unit, and in this case, the operation of attaching and detaching the cartridge unit can be made simpler.

Other objects and features of the present invention will become apparent from the following description of embodiments with reference to the drawings.

[0010]

FIG. 1 shows an embodiment of the present invention. The photoconductor 1 is neutralized by light irradiation by the light emitter 20 for neutralization, and the surface potential is averaged to a reference potential of 0 to -150V. Next, it is charged by the charging roller 2 and the surface potential is -110.
It will be around 0V. This is the pre-charged potential immediately before exposure to image light. Next, an exposure device DSR formed by an illumination lamp, a mirror, and a lens for projecting an original image on a photoconductor, in the optical exposure direction, or in a laser scanning direction for modulating scanning laser light in accordance with an image signal. The image potential is projected and the part irradiated with the light (image part) has a surface potential of 0 to -290 V and the developing sleeve 3 is biased at about -800 V, so the image part is developed. The toner on the sleeve 3 adheres. The transfer paper is fed from a paper feed unit (not shown) so that the front end of the transfer paper is aligned with the front end of the image on the photoconductor with respect to the toner image on the photoconductor. The toner image on the surface is transferred to the transfer paper. The transfer paper is sent to a fixing unit (not shown), the toner is fused to the transfer paper by heat and pressure, and the transfer paper is discharged as a copy.

On the other hand, the residual toner remaining on the photosensitive member is scraped off by the cleaning blade 10 and the photosensitive member 1
Becomes a clean state without toner, and moves to the next image forming process again. The above is the basic function.

The photoreceptor 1, the charging roller 2, the developing roller 3, the transfer roller 8 and the cleaning blade 10 as well as the mechanism and the additional elements for supporting them are the cartridge case 18. It is housed inside. Among them, the residual toner recovered by the cleaning device including the blade 10 is transported by the toner transport coil 11 and sent to the recycle toner transport section in the case 18, where it is recycled. The belt 12 sends the developer agitating section 5 to recycle the toner. This recycle transport unit 5 is also integrated with the case 18, so that there is no need to worry about toner leaks at the joints when they are separated, and no sponge member is added to prevent this. You may
Moreover, since it is integrated, the assembling property is also improved.

The charging roller 2 has a structure in which a conductive metal rubber (epichlorohydrin rubber) is wound around an outer circumference of a metal cored bar, and is in contact with the photoconductor 1 during a charging operation. In this case, if the machine is stopped and left in contact for a long period of time, the photoconductor is contaminated and an abnormal image is generated. Therefore, it is necessary to separate the photoconductor 1 from the photoconductor 1 when the machine is stopped. Further, during charging operation, the charging roller 2 is kept in contact with the photoconductor 1, so that the surface of the charging roller 2 becomes dirty and uneven charging occurs due to the small toner. In order to prevent this, it is necessary to mount a pad for cleaning the charging roller 2, and a cleaning pad 2-2 is mounted.

FIG. 2 is an exploded view of a charging device including the charging roller 2. The charging roller 2 has conductive bearings 2-3 at both ends.
These bearings 2-3 are rotatably supported by a charging roller.
The rack 2-1 is supported so as to be able to move back and forth in a direction orthogonal to the roller axis, and the roller axis is always separated by the compression coil spring 2-4 from the charging roller 2-1 (Roll). -La 2
Is pressed toward the photoconductor 1). The charging roller case 2-1 is attached to the cartridge case 18 (FIG. 1),
It is supported so as to be movable back and forth in a direction orthogonal to the roller axis, and is constantly charged by a compression coil spring 2-5.
Is pushed in a direction away from the photoconductor 1. That is,
In the cartridge case 18, the charging roller case 2-1
Is pressed by a spring 2-5 in a direction away from the photoconductor 1. The charging roller 2 is pushed by a spring 2-4 in a direction away from the charging roller case 2-1 (a direction approaching the photoconductor 1). Since -1 is separated from the photoconductor 1 by the spring 2-5, the charging roller 2 pushed toward the photoconductor 1 by the spring 2-4 is largely separated from the photoconductor 1.

The main frame of the main body on which the cartridge case 18 is mounted has a rotary arm 13, and when the cartridge case 18 is mounted on the main frame of the main body, the tip of the rotary arm 13 is shown. The charging roller case 2-1 is located immediately below. The case 18 has an opening into which the tip of the rotating arm 13 and the light emitting device 20 supported by the rotating arm 13 can be inserted, and the cartridge case 18 is attached to the main body frame. , Rotating arm 1
When the tip end of the charging roller 3 rotates in the direction in which the tip of the charging roller 3 descends in FIG. 2, the charging roller case 2-1 approaches the photoconductor 1 while compressing it against the repulsive force of the spring 2-5. And the charging roller 2 contacts the photoconductor (charging position). When driven further in the same direction, the charging roller case 2-1 moves in the direction approaching the photoconductor 1, but the charging roller 2-1 moves toward the charging roller.
Since the movement of the roller 2 is blocked by the photoconductor 1, the charging roller case 2-1 approaches the charging roller 2 while the spring 2-4 is being compressed, and is attached to the case 2-1. The cleaned cleaning pad is pressed against the charging roller 2 (cleaning position). When the rotating arm 13 returns and rotates, the tip of the rotating arm 13 is charged to the charging roller case 2-1 through the reverse process.
And exit the opening of the cartridge case 18 (withdrawal position). The three charging roller positions are as follows.

(1) The charging roller case 2-1 is pushed down to some extent and comes into contact with the charging roller 2 photoconductor, and the charging position where the charging operation is performed, (2) the charging roller case 2-1 is It is pushed down further, and the cleaning pad 2-2 is attached to the charging roller 2.
Position where pressure is applied (cleaning position), and (3)
The charging roller case 2-1 returns to the top, and the charging roller 2
Is a position separated from the cleaning pad 2-2 and the photoconductor 1 (retracted position).

The position (3) above is shown in FIG.
The position of the above (1) is shown in (b), and the above (2) is shown in (c).
Indicates the position of.

Referring again to FIG. 1, the above (1)-
(3) is determined by the rotation angle of the rotation arm 13 provided on the main body, and this rotation angle is determined by the cam 15. The cam 15 is formed integrally with the rotary shaft of the electromagnetic clutch 16, and when the electromagnetic clutch 16 is energized once, the cam 15 rotates 120 °. Therefore, each of the above three positions can be determined by how many times the electromagnetic clutch 16 is energized.

FIG. 3 shows the relationship between the rotary arm 13 and the cam 15. A bearing (not shown) is fixed to the machine frame mounting bracket 13-1 and a shaft rod (not shown) that penetrates the bearing.
Two pivoting arms 13 are fixed to each other. An arm that abuts on the cam 15 is integrated with one rotating arm 13, and this arm is pressed against the cam 15 by a compression coil spring. The light emitting device 20 that photo-electrifies the photoconductor 1 immediately before the photoconductor 1 is charged by the charging roller 2 is fixed near the tip of the rotating arm 13, and the (1),
In the state of (2), it is installed so as to have a desired distance from the photoconductor (the distance between the light emitter 20 and the photoconductor 1 is 30 mm). In the state of (2), the light emitting device 20 may be turned on or off depending on the pre-processing and post-processing of image formation (a static elimination effect can be expected). Further, in the state (3), the light emitter 20 provided on the rotating arm 13 is farther from the photoconductor 1 and outside the cartridge case 18 than in the states (1) and (2). Therefore, dirt due to toner scattering during standby is reduced, and a stable amount of static elimination light can be secured.

FIG. 5 schematically shows the main elements around the photoconductor 1 shown in FIG. In the above-described embodiment, the light emitter 20 for removing the charge on the surface of the photoreceptor after cleaning is supported by the rotating arm 13 and driven from outside the opening of the cartridge case 18 to the inside thereof. However, in the process from the charging (2) to the developing (3), the light emitting device 21 for erase erase of the area for eliminating the image formation unnecessary area is provided with the above-mentioned rotating arm 13 and it. The advancing / retreating drive with respect to the photoconductor 1 may be performed by using a contact / separation mechanism similar to the mechanism for rotationally driving. If necessary, the charging roller 2 and / or the developing device 3 may be simultaneously driven to the retracted position / acting position by such a contact / separation mechanism. Similarly, the light emitting device 22 for reducing the potential of the toner image appearing on the surface of the photosensitive member 1 by the development is connected to the rotating arm 13 and the contact / separation mechanism similar to the mechanism for driving the rotating arm 13. Using photoconductor 1
Alternatively, it may be driven forward and backward. If necessary, the developing device 3 and / or the transfer roller 8 may be simultaneously driven to the retracted position / acting position by such a contact / separation mechanism. Further, similarly, the light emitter 23 for erasing the residual toner potential after the transfer is formed by using the rotating arm 13 and the contacting / separating mechanism similar to the mechanism for driving the rotating arm 13 described above. Alternatively, it may be driven forward and backward. If necessary, the transfer roller 8 and / or the cleaning device 5 may be simultaneously driven to the retracted position / acting position by such a contacting / separating mechanism.

According to the above-described embodiment, since the light-emitting device 20 for static elimination is provided on the other functional component (the pivotal arm 13 for pressing and releasing the charging device), the holding member such as the bracket is provided. Since it is not necessary to provide it, the cost can be reduced. Except during the image forming process, the light emitter 20 is located farther from the surface of the photoconductor than the position required for the image forming process (light irradiation position) (retracted position), so that contamination due to toner scattering is suppressed to a minimum. As a result, a stable amount of static elimination light can be secured at all times.

[Brief description of drawings]

FIG. 1 is a side view of a main part of an embodiment of the present invention.

FIG. 2 is an exploded perspective view of a charging device including the charging roller 2 shown in FIG.

FIG. 3 is an exploded perspective view of a contacting / separating mechanism including a rotating arm 13 shown in FIG.

FIG. 4 is a side view of the rotating arm 13 shown in FIG.
(A) shows the state in which the rotating arm 13 is at the retracted position,
(B) shows the state at the charging position, and (c) shows the state at the cleaning position.

FIG. 5 is a block diagram showing in simplified form the photoconductor 1 shown in FIG. 1 and some elements around it.

[Explanation of symbols]

1: Photosensitive member 2: Charging roller 2-1: Charging roller case 2-2: Cleaning pad 2-3: Conductive bearing 2-4: Compression coil spring 2-5: Compression coil spring 2 -6: Electrode (for applying bias to roller) 2-7: Gear (for driving roller) 3: Developing sleeve 4: Doctor blade 5: Stirring screw 6: End toner replenishing section 7: Toner bottle 8: Transfer roller 9: Charge elimination needle 10: Cleaning blade 10-1: Blur
Holder 11: Toner-conveying screw 12: Toner-recycle belt 13: Charging roller contact / separation arm 14: Thermistor 15: Cam 16: Electromagnetic clutch

Claims (3)

[Claims] 1. A photoconductor, a charging device for charging the photoconductor, an exposing means for exposing a charged surface of the photoconductor to image light, a developing device for visualizing an electrostatic latent image generated by the exposure, and a photoconductor for the photoconductor. In an image forming apparatus provided with a transfer means for transferring an image onto a transfer paper, a light emitter for irradiating light on a photoconductor and a light emitting position for moving the light emitter near a photoconductor to a retracted position far from the photoconductor and vice versa. An image forming apparatus comprising: a contacting / separating mechanism that is driven by 2. A photoconductor, a charging device for charging the photoconductor, an exposing means for exposing the charged surface of the photoconductor with image light, a developing device for visualizing an electrostatic latent image generated by the exposure, and a photoconductor for the photoconductor. In an image forming apparatus including a transfer unit that transfers an image onto a transfer sheet, a contacting / separating mechanism including a lever member for driving the charging device from a retracted position far from the photoconductor to a charging position close to the photoconductor, and the lever. A light emitting device that is supported by a member and that moves the charging device from a retracted position far from the photoconductor to a charging position close to the photoconductor to a light irradiation position close to the photoconductor from the retracted position far from the photoconductor. An image forming apparatus characterized by the above. 3. The image forming apparatus according to claim 1, wherein the photoconductor and the charging device are installed in a case that is detachable from a machine frame that supports the contacting / separating mechanism.