JP3420654B2 - Image forming device - Google Patents

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 photosensitive member is charged, a charged surface is exposed to image light to form an electrostatic latent image, and the electrostatic latent image is visualized by a developing device. Related to an image forming apparatus. This type of image forming apparatus is used in, for example, a copying machine, a facsimile, a printer, and the like.

[0002]

2. Description of the Related Art In an electrophotographic image forming apparatus,
Immediately before or immediately after forming an electrostatic latent image, an illuminator for erasing (including a light emitting element such as a light emitting diode) for irradiating light to the outside of the original image area of the photoreceptor to remove electricity is formed by developing. Light-emitting device 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 photoconductor surface after the transfer of the developed image to transfer paper. A light eliminator for light removal to reduce electrostatic attraction to the photoreceptor, and
One or two or more types of erasing devices for erasing residual charges by irradiating the cleaned photoreceptor surface with light to remove residual toner are provided.

[0003]

The static eliminator as described above is:
The light emitting unit (LED) and the electric circuit board are attached to a holding member such as a sheet metal, and the cost is increased because the holding member is attached to the apparatus main body. Conventionally, the photoconductor has always been fixed at a position where the photoconductor is neutralized. As a result, the light emitting device may be contaminated by scattering of toner from the development and the like, and the static elimination effect may be reduced. That is, since the distance from the photoreceptor is short, the toner is easily stained by the toner. If the toner is soiled, the light irradiation becomes uneven and the desired static elimination cannot be realized. Also, recently, when a photoreceptor and other image forming process elements are used as a cartridge unit, for example, when a predetermined number or more of images are formed, the cartridge is replaced.
The process element is simply updated to one without deterioration. Since the above-mentioned light emitter is provided as a component outside the cartridge unit on the main body side where the cartridge unit is attached and detached, the light emitter does not hit the cartridge when the cartridge is mounted on the main body, and the photosensitive member is An air gap for receiving the light emitter is required so that the light emitter is located in the immediate vicinity, and this gap becomes a long slit extending in the axial direction parallel to the photoconductor, so that the structure of the cartridge is complicated.

A first object of the present invention is to suppress contamination of a light emitting device, and a second object of the present invention is to simplify a cartridge unit and to facilitate an attaching / detaching operation.

[0005]

An image forming apparatus according to the present invention comprises a photosensitive member (1), a charging device (2) for charging the photosensitive member, and an exposure device (DSR) for exposing the charged surface of the photosensitive member to image light. An image forming apparatus comprising: a developing device (3) for visualizing an electrostatic latent image generated by exposure; and transfer means (8) for transferring a visualized image of a photoconductor to transfer paper. Support and said
A charging device (2), from a distant retracted position from the photosensitive member (1) the photoreceptor
Supporting the movably charged position close to, detachable from the machine frame
Freely Ke - scan (18); emitter for irradiating light to the photosensitive member (1) (20); and, the light emitting device which supports the (20)
Outside of the case (18), from a distant retracted position from the photosensitive member (1) moves the light irradiation position close to the photosensitive member, the charging this time
A contact / separation mechanism (13 to 16, 31) provided on the machine frame side for driving the device (2) to the charging position .

[0006] In order to facilitate understanding, the symbols of the corresponding elements of the embodiment shown in the drawings and described later are added in parentheses for reference.

[0007]

According to the action and effect] above Kitoku symptoms, contact and separation mechanism (1:13
By driving the light emitting device (20) to the light irradiation position near the photoconductor (1) via the light emitting device (6, 31), the light emitting device (20) can irradiate the photoconductor (1) with light in the same manner as before. Can be. When light irradiation is unnecessary, the light emitting device (20) can be placed at a retracted position farther than the photoconductor (1) via the contact / separation mechanism (13 to 16, 31), and the light emitting device (20) is in the retracted position. Since the photoconductor (1) is at a long distance from the photoconductor (1), the light emitting device (20) is less contaminated by toner. Further, when the photosensitive member and other image forming process elements are cartridge units, the light-emitting device
Since (20) is at the retracted position, the degree of freedom in the structure for attaching and detaching the cartridge unit is increased, the cartridge unit can be simplified, and the attaching and detaching operation can be simplified.

Further , as the light emitting device (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 contaminated by toner. Also, the charging device should be a cartridge .
Because of this , the attachment / detachment operation of the cartridge unit can be further simplified.

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 emitting device 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 has a surface potential of -110.
It becomes around 0V. This is the pre-charge potential immediately before image light exposure. Next, an exposure device DSR in an optical exposure direction comprising an illumination lamp, a mirror and a lens for projecting a document image on a photosensitive member, or in a laser scanning direction for modulating a scanning laser beam according to an image signal. The image potential is projected on the portion (image portion), and the surface potential becomes 0 to -290 V, and the developing sleeve 3 is biased at around -800 V. The toner on the sleeve 3 adheres. A transfer sheet is fed from a paper supply unit (not shown) so that the leading end of the transfer paper is aligned with the leading end of the image on the photosensitive body with respect to the toner image on the photosensitive body. The toner image on the surface is transferred to a transfer paper. The transfer sheet is sent to a fixing section (not shown), the toner is fused to the transfer sheet by heat and pressure, and the transfer sheet is discharged as a copy.

On the other hand, the residual toner remaining on the photoreceptor is scraped off by a cleaning blade 10 and the photoreceptor 1
Is in a state without toner, and the process proceeds to the next image forming step again. The above is the basic operation.

The photosensitive member 1, the charging roller 2, the developing roller 3, the transfer roller 8 and the cleaning blade 10 and the mechanism and additional elements for supporting them are a cartridge case 18. Is stored within. The residual toner collected by the cleaning device including the blade 10 is conveyed by the toner conveying coil 11 and sent to a recycle toner conveying section in the case 18, where the toner is recycled. The developer is sent to the developer agitating section 5 by the belt 12, and the toner is recycled. The recycle transport section 5 is also integrated with the case 18 so that there is no need to worry about toner leakage at the joint when it is made separate and to add a sponge member to prevent this. May be.
Also, since they are integrated, the assemblability is also improved.

The charging roller 2 has a structure in which a core metal is wound around a metal with conductive raw rubber (epichlorohydrin rubber), and is in contact with the photoreceptor 1 during a charging operation. In this case, the photoconductor is contaminated if left in contact with the machine for a long period of time and an abnormal image is generated. Therefore, it is necessary to keep the photoconductor 1 away from the photoconductor 1 when the machine is stopped. In addition, since the charging roller 2 is kept in contact with the photoreceptor 1 during the charging operation, the surface of the charging roller 2 becomes dirty due to minute toner, causing uneven charging. In order to prevent this, it is necessary to attach a pad for cleaning the charging roller 2, and the cleaning pad 2-2 is attached.

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.
And these bearings 2-3 are charged rotatably.
The roller 2-1 is supported by the case 2-1 so as to be able to advance and retreat in a direction orthogonal to the roller axis, and the roller axis is always moved away from the charging roller case 2-1 by the compression coil spring 2-4. -La 2
Is pressed toward the photoconductor 1). The charging roller case 2-1 is connected to the cartridge case 18 (FIG. 1).
The charging roller case 2-1 is supported by a compression coil spring 2-5 so as to be movable forward and backward in a direction perpendicular to the roller shaft.
Is pushed in a direction away from the photoconductor 1. That is,
The charging roller case 2-1 in the cartridge case 18
Is pressed by a spring 2-5 in a direction away from the photoreceptor 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 photoreceptor 1) with respect to the charging roller case 2-1. Since -1 is farther away from the photoconductor 1 by the spring 2-5, the charging roller 2 pressed toward the photoconductor 1 by the spring 2-4 is far from the photoconductor 1.

The main body frame on which the cartridge case 18 is mounted has a rotating arm 13. When the cartridge case 18 is mounted on the main body frame, the tip of the rotating arm 13 is moved. The charging roller case 2-1 is located immediately below. The case 18 has an opening through which the light-emitting device 20 supported by the tip of the rotating arm 13 and the rotating arm 13 can enter. When the cartridge case 18 is mounted on the body frame of the main body. , Rotating arm 1
When the roller 3 rotates in the direction in which its tip is lowered in FIG. 2, the charging roller 2-1 approaches the photosensitive member 1 while compressing it against the repulsive force of the spring 2-5. , The charging roller 2 comes into contact with the photosensitive member (charging position). When further driven in the same direction, the charging roller case 2-1 moves in the direction approaching the photoreceptor 1;
Since the roller 2 is prevented from moving by the photoreceptor 1, the charging roller case 2-1 approaches the charging roller 2 while the spring 2-4 is compressed, and is mounted on the case 2-1. The cleaned pad is pressed against the charging roller 2 (cleaning position). When the rotating arm 13 returns and rotates, the leading end of the rotating arm 13 goes through the reverse process, and the charging roller case 2-1 is moved.
Out of the opening of the cartridge case 18 (retracted position). The three charging roller positions are as follows. (1) The charging roller case 2-1 is depressed to some extent, and the charging roller 2 comes into contact with the photoreceptor, and the charging position where the charging operation is performed. (2) The charging roller case 2-1 is further depressed. A position where the cleaning pad 2-2 is pressed against the charging roller 2 (cleaning position); and (3) the charging roller case 2-1 returns to the uppermost position, and the charging roller 2 Indicates a position (retreat position) separated from the cleaning pad 2-2 and the photoconductor 1.

FIG. 4A shows the position of the above (3).
(B) shows the position of (1), and (c) shows the position of (2).
Indicates the position of.

Referring to FIG. 1 again, the above (1) to (4)
(3) is determined by the rotation angle of the rotating arm 13 provided in the main body, and this rotation angle is determined by the cam 15. The cam 15 is formed integrally with the rotating shaft of the electromagnetic clutch 16, and when the electromagnetic clutch 16 is energized once, the cam 15 rotates 120 °. For this reason, it is possible to determine each of the above three positions depending on how many times the electromagnetic clutch 16 is energized.

FIG. 3 shows the relationship between the rotating 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) penetrating this bearing
, Two rotating arms 13 are fixed. One rotating arm 13 is integrally formed with an arm that contacts the cam 15, and this arm is pressed against the cam 15 by a compression coil spring. A light emitting device 20 for light-eliminating the photoconductor 1 immediately before charging the photoconductor 1 by the charging roller 2 is fixed near the tip of the rotating arm 13, and the light emitting device 20 described in (1) and (2) above is used.
In the state of (2), it is installed so as to have a desired distance from the photoconductor (the distance between the light emitting device 20 and the photoconductor 1 is 30 mm). In the state (2), the light emitter 20 may be turned on or off in relation to the pre-imaging processing and the post-processing (a charge eliminating effect can be expected). In the state (3), the light emitting device 20 provided on the rotating arm 13 is farther from the photosensitive member 1 than in the states (1) and (2) and outside the cartridge case 18. , 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 components around the photoreceptor 1 shown in FIG. In the above-described embodiment, the light-emitting device 20 for removing static electricity from the photoreceptor surface after cleaning is supported by the rotating arm 13, and is driven from the outside of the opening of the cartridge case 18 to the inside thereof to drive the photoreceptor. In the process from the charging (2) to the development (3), the erasing light emitting device 21 for removing the image forming unnecessary area is replaced with the rotating arm 13 and the rotating arm 13 described above. May be driven forward and backward with respect to the photoreceptor 1 by using a contact / separation mechanism similar to the mechanism for rotationally driving the photoconductor 1. If necessary, the charging roller 2 and / or the developing device 3 may be simultaneously driven to the retreat position / action 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 photoreceptor 1 due to the development is connected to the rotating arm 13 and a mechanism similar to the mechanism for driving the rotating arm. Photoconductor 1 using
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 / operating position by such a contact / separation mechanism. Further, similarly, the light emitting device 23 for erasing the residual toner potential after the transfer is transferred to the photosensitive member 1 by using the above-described rotating arm 13 and a contact / separation mechanism similar to the mechanism for rotating the rotating arm 13. 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 / operating position by such a contact / separation mechanism.

According to the embodiment described above, the light-emitting device 20 for static elimination is provided on another functional component (the rotating arm 13 for pressing and releasing the charging device) so that the holding member such as a bracket can be provided. There is no need to provide it, and cost reduction is possible. By setting the light emitter 20 at a position (retreat position) farther from the surface of the photosensitive member than a position (light irradiation position) required in the image forming process except during the image forming process, dirt due to toner scattering is suppressed to a minimum. As a result, a stable amount of static elimination light can always be secured.

[Brief description of the 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 contact / separation mechanism including a rotating arm 13 shown in FIG.

4 is a side view of the rotating arm 13 shown in FIG. 1,
(A) shows a state in which the rotating arm 13 is in the retracted position,
(B) shows the state at the charging position, and (c) shows the state at the cleaning position.

FIG. 5 is a simplified block diagram showing a photoconductor 1 shown in FIG. 1 and some components around the photoconductor 1;

[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: Toner replenishing section 7: Toner bottle 8: Transfer roller 9: Static elimination needle 10: Cleaning blade 10-1: Blade holder 11: Toner transport screw 12: Toner recycling belt 13: Charging roller contact / separation arm 14: Thermistor 15: Cam 16: Electromagnetic clutch

Continuation of the front page (56) References JP-A-5-61389 (JP, A) JP-A-3-130787 (JP, A) JP-A-7-104635 (JP, A) JP-A-2-210482 (JP) , A) Hikaru 2-95363 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name)

Claims (3)

(57) [Claims] 1. A photoconductor, a charging device for charging the photoconductor, an exposure unit for exposing image light to a charged surface of the photoconductor, a developing device for visualizing an electrostatic latent image generated by the exposure, and a developing device for the photoconductor. In an image forming apparatus including a transfer unit that transfers an image to transfer paper, the image forming apparatus supports the photoconductor and moves the charging device away from the photoconductor.
From the evacuation position to the charging position near the photoconductor.
That, freely Ke detachable from the machine frame - scan; emitter for irradiating light to the photosensitive body; and, outside of the case it supports the light emitting device, farther retracted position from the photosensitive member From, move to the light irradiation position close to the photoconductor ,
At this time , a machine frame for driving the charging device to the charging position
An image forming apparatus comprising: a contact / separation mechanism provided on the side . Wherein said moving mechanism comprises a mechanism for driving the record <br/> bar member and the lever member for supporting the light emitting device; before
Serial case, when the lever member moves the light irradiation position close to the photosensitive member from a distant retracted position the emitter from the photosensitive member
Having an opening through which the light emitter and lever member can enter;
The image forming apparatus according to claim 1. 3. The charging device is detachable from a machine frame.
In the case described above, the retracted position far from the photoconductor is close to the photoconductor.
Charging roller case movably supported at a charging position
Moveable and retractable in the same direction as the movable direction with the charging roller case
The feeling supported charging roller, and such a charging roller
The image forming apparatus according to claim 1 , further comprising a spring member that presses in a direction approaching the light body .