JPH0693151B2 - Image forming apparatus and cartridge - Google Patents

Description

TECHNICAL FIELD The present invention relates to an image forming apparatus such as an electrophotographic apparatus or an electrostatic recording apparatus such as a copying machine or a laser beam printer.
In particular, it relates to cleaning a corona discharge device used in this image forming apparatus.

(Prior Art) Conventionally, in the above image forming apparatus, a corona discharge device for generating a corona discharge by applying a high voltage to a wire having a wire diameter of about 0.1 mm is used for charging or discharging the image carrier. Has been done.

However, in the above-mentioned corona discharge device, the corona discharge wire as the corona discharge electrode is liable to be contaminated by the developer and other foreign matter, and there is a problem that uneven discharge occurs due to the contamination. Further, when an image is formed while the corona discharge wire is dirty, there is a drawback that the discharge unevenness clearly appears as unevenness on the image. Therefore, the corona discharge wire must always be kept clean and free from dirt.

Therefore, various methods for cleaning the corona discharge wire have been conventionally considered.

For example, there is a method in which a cleaner is fixed to the main body of the image forming apparatus so as to contact the corona discharge wire, and the corona discharge device itself is inserted into and removed from the main body device to clean the wire. (Public Publication No. 51-1830)
However, with this method, when performing maintenance other than wire cleaning such as wire height adjustment on the corona discharge device, the corona discharge device cannot be pulled out unless the cleaner is removed from the main device each time. There was an inconvenience.

Also known is a corona discharge device itself provided with means for cleaning the corona discharge wire by sliding a rod or the like (US Pat. No. 3,942,006), but such a device generally complicates the device. However, there was a drawback that it became larger.

On the other hand, recently, image carriers, corona discharge devices, developing devices,
2. Description of the Related Art Image forming apparatuses such as cleaning devices, which are directly related to image formation and in which process elements that require particularly sufficient maintenance are housed in a single cartridge and each cartridge is replaced instead of maintenance, have become widespread. However, this device does not have a structure for removing or inserting the corona discharge device, etc. in order to reduce the cost and waste of the fixing method of each process element, etc., and fix the corona discharge device to the frame of the cartridge with screws etc. The configuration is as simple as possible. Also, since the inside of the cartridge is basically not touched from the outside, it is necessary to devise a method for cleaning the corona discharge wire. Regarding the cleaning of the corona discharge wire in such an image forming apparatus, as shown in JP-A-59-34556 and JP-A-59-34545 by the applicant of the present application, the rear side of the corona discharge device is used. There is one in which a slip opening is formed in the cartridge frame body, and a separate cleaner is inserted from this opening to clean the corona discharge wire. However, this cleaner is considered as a supplemental measure for a device with relatively low contamination of the corona discharge wire in the case of a copy volume of about 2,000 to 3,000 sheets per cartridge, and has a larger copy volume. For the cartridge corresponding to the apparatus, it is necessary to clean the corona discharge wire easily and surely.

(Object of the Invention) It is an object of the present invention to provide an image forming apparatus and a cartridge in which the above-mentioned conventional drawbacks for cleaning the corona discharge electrode are eliminated.

Another object of the present invention is to provide an image forming apparatus and a cartridge having excellent operability for cleaning the corona discharge electrode.

(Summary of the Invention) The present invention provides a side plate of the image forming apparatus main body when the cleaner is not located at the predetermined position of the corona discharge device or the predetermined position of the cartridge, and when the corona discharge device or the cartridge is attached to the image forming apparatus. A stopper provided on the inner side is engaged with the cleaner to relatively move the cleaner to a predetermined position of the corona discharge device or the cartridge.

(Example) Hereinafter, the Example of this invention is described based on drawing.

FIG. 1 shows an electrophotographic copying apparatus as an example of an image forming apparatus.

The photoconductor drum 1, which is an image carrier, is uniformly charged by the corona discharge device 10. The corona discharge device 10 is attachable to and detachable from the main body of the image forming apparatus. Details of the corona discharge device will be described later. The uniformly charged image carrier 1 moves while being illuminated by a document illumination lamp 3 supported by a document support table 2, so that a light image corresponding to the document is exposed via the imaging optical means 4. To be done. As a result, an electrostatic latent image is formed on the image carrier. The formed electrostatic latent image is visualized by the developing device 5. The visible image is transferred by the transfer corona discharge device 7 onto the transfer material moving from the cassette 6 while being timed by the feeding roller and the registration roller. The transfer material on which the visible image has been transferred is separated from the image carrier by a separating means (not shown), and then is conveyed to the fixing device 8 by the conveying means to fix the image.
After that, the transfer material is discharged onto the tray T by the discharge roller.

On the other hand, the residual toner on the image carrier is removed by the cleaning device 9, and the image carrier is reused for the next image formation.

Next, a corona discharge device used in the image forming apparatus of the present invention will be described with reference to FIGS.

The corona discharge device 10 is a conductive shield member 11a, 11a that forms a corona discharge opening for the image carrier 1 which is a member to be stripped.
have b. Plate-shaped members 12a and 12b having an L-shaped cross section are fixed to the shield members 11a and 11b by spot welding or the like. The shield member and the plate-shaped members form a guide portion 13 extending in the longitudinal direction of the corona discharge device. Is forming. The slide portion 21 of the cleaner 20 is guided by the guide portion 13, and the cleaner 20 is movable along the guide portion 13 in the longitudinal direction of the corona discharge wire.

As shown in FIG. 3, one end of the corona discharge wire 14 is locked to the power feeding portion 15 provided on the rear insulating support block 28 via a tension spring, and the other end is connected to the front insulating block.
It is fixed to 27 with screws 16. Further, the corona discharge wire 14 is engaged with a positioning member 17 provided on each of the insulating support blocks 27 and 28, and the positioning member 17 can be moved in the vertical direction by an adjusting screw 18. Therefore, the positioning member 17 is moved by adjusting the adjusting screw 18, and the image carrier 1 of the corona discharge wire 14 is moved.
The distance from can be set to an appropriate value. Incidentally, 19
Is a grid electrode for controlling the surface potential of the image carrier 1.

Here, the cleaner 20 will be explained.
A knob portion 22 protruding to the back side of the corona discharge device is provided on the upper portion of 21, and an arm portion 23 is provided on the opposite side. Further, an elastic arm portion 24 having elasticity is attached to the arm portion 23. At the tip of the elastic arm 24, there are provided a cleaning unit 25 that contacts the corona discharge wire 14 that is a corona discharge electrode to clean the corona discharge wire, and a holding unit 26 that holds the cleaning unit 25. Due to its elasticity, the elastic arm 24 presses the cleaning unit 25 against the corona discharge wire 14 with a predetermined pressing force (about 100 to 300 g) at least when cleaning the corona discharge wire 14 by the cleaning unit 25. Has become.

The shape of the elastic arm 24 can be determined by the tension of the corona discharge wire 14, the position adjustment width of the wire adjusted by the movement of the positioning member 17, the material of the cleaning unit 25, and the like for a predetermined pressing force.

On the other hand, the corona discharge device 10 is attachable / detachable to / from a support member 32 which is itself fixed to a frame 30 on the image forming apparatus main body side by a fixing member such as a screw 31. Specifically, the protrusions 2 of the insulating support blocks 27, 28 before and after the corona discharge device 10 are
The 7a and 28a are engaged with the guide rail portions 32a and 32a of the support member 32 so that the corona discharge device 10 can be inserted and removed in the direction of arrow A (FIG. 3). Further, the corona discharge device 10 is screwed in the state in which it is attached to the main body device (FIG. 3).
The plate spring 33 attached to the support member 32 presses the image bearing member 1 side. And corona discharge device
After 10 is inserted along the support member 32, the frame 35 on the main body side and the rear insulating support block 28 of the corona discharge device 10 are engaged with each other for positioning in the front-rear direction (direction of arrow A). Done. Reference numeral 29 is a handle for attaching / detaching the corona discharge device 10 to / from the image forming apparatus main body.

Here, an operation method for cleaning the corona discharge wire 14 will be described.

As shown in FIG. 3, from the state in which the corona discharge device 10 is attached to the image forming apparatus main body, the corona discharge device 10 is pulled out by pulling the corona discharge device 10 toward the front (to the left in the drawing) with the grip 29. Is separated from the main body of the image forming apparatus. After that, by holding the knob portion 22 of the cleaner 20 and reciprocating the cleaner 20 in the longitudinal direction of the corona discharge device,
The corona discharge wire 14 is cleaned by the cleaning unit 25.

When the corona discharger is mounted after cleaning the wires, the block 28 is attached to the body frame while the projection 28a of the rear insulating support block 28 and the guide rail portion 32a of the support member 32 are engaged with each other. The corona discharge device 10 is inserted into the image forming apparatus until it hits the body 35. This completes the mounting of the corona discharge device on the main body of the image forming apparatus.
This position is the operating position of the corona discharge device.

By the way, after cleaning the corona discharge wire, the cleaner 20 is moved to a position that does not affect the charging action of the end of the insulating support block 27 as shown by the solid line in FIG. For example, when the corona discharger is mounted in the image forming apparatus with the cleaner 20 in the position shown by the chain line 20 'in FIG. 3, the part where the cleaner 20 is located Uneven charging occurs. That is, not only the area to be charged is shielded by the cleaner 20, but also the cleaning portion 25 of the cleaner 20 is in contact with the wire 14 with a predetermined pressing force. The distance changes, and uniform charging cannot be performed.

Therefore, in the present invention, in order to prevent such a situation, a stopper 36 is provided on a part of the support member 32 that supports the corona discharge device 10. The stopper 36 is provided inside the side plate of the image forming apparatus main body. As a result, the cleaner 20 is not in the predetermined home position (the position shown by the solid line in FIG. 3 in this embodiment), for example, 2 in FIG.
Even if the corona discharge device 10 is attached to the main body of the image forming apparatus with the cleaner 20 placed at the position shown by the dashed line 20 ′,
As the corona discharge device is inserted, the knob portion 22 of the cleaner 20 contacts the stopper 36, and the cleaner 20 is inserted in the corona discharge electrode in the direction opposite to the insertion direction of the corona discharge device.
Are relatively moved, and the cleaner 20 is returned to the predetermined position. Therefore, even if the cleaner 20 is forgotten to be moved to the position shown by the solid line in FIG. 3 after cleaning the corona discharge wire, the cleaner 20 is always moved to the position shown by the solid line in FIG. 3 as the corona discharge device is inserted into the image forming apparatus. It can be moved relatively. Therefore, it is possible to surely eliminate the above-mentioned inconvenience such as uneven charging. Further, since the stopper 36 is provided inside the side plate of the image forming apparatus main body, the number of corona discharge devices protruding outside the side plate is small, so that the length of the image forming apparatus can be shortened.

Further, the cleaner 20 is at the position shown by the solid line in FIG. 3 (this position is the home position of the cleaner 20 in this embodiment). If yes, corona discharge wire 14 and cleaner
If the cleaning unit 25 of 20 is still in contact with the corona discharge wire 14, it is difficult to perform positioning such as height adjustment. Therefore, in this embodiment, the front insulating support block 27 is provided with an inclined portion 27b as shown in FIG. The protrusion 26a (FIG. 2) of the holding portion 26 of the cleaner 20 is guided by the inclined portion 27b, and the holding portion 26 moves in the direction away from the wire 14 against the elastic force of the elastic arm portion 24. As a result, when the corona discharge wire 14 is not cleaned, that is, when the cleaner 20 is at the position shown by the solid line in FIG. 3, the cleaning portion 25 of the cleaner 20 is separated from the corona discharge wire 14.

The corona discharger which is detachable from the image forming apparatus main body has been described above.
A second embodiment of the present invention will be described with reference to FIGS.

In this embodiment, the image carrier 1, the corona discharge device 10, the developing device 5, the cleaning device 9 and other process means for forming an image are housed in a cartridge C (indicated by a two-dot chain line) as one unit. The cartridge C is attachable to and detachable from the image forming apparatus main body in the direction of arrow B (FIG. 4). What is accommodated in the cartridge C is not necessarily limited to that of this embodiment, and any process means can be selected and accommodated. For example, the image carrier 1, the corona discharge device 10, and the cleaning device 9 may be housed in a cartridge, and the developing device 5 may be detachable from the image forming apparatus. In this way, the developer can be replenished by replacing only the developing device. In some cases, each process means in the cartridge can be individually attached to and detached from the cartridge.

Here, the corona discharge device in the cartridge C will be described. Those having the same functions as those of the corona discharger described in FIGS. 2 and 3 are designated by the same reference numerals.

The corona discharge device 10 is fixed to the frame 40 of the cartridge C by a fixing member such as a screw 31. The slide portion 21 of the cleaner 20 is movable in the longitudinal direction of the corona discharge wire using the opening 11C on the opposite side of the discharge opening of the shield member 11 of the corona discharge device 10 as a guide. The knob portion 22 of the cleaner 20 projects to the outside of the frame body 40 through the slit opening 40a of the frame body 40 of the cartridge C. still,
Other configurations of the cleaner are similar to those described above.

Further, a flexible light-shielding sheet 41 such as a black mylar sheet or a rubber sheet is provided in the slit opening 40a of the cartridge in order to prevent outside light, dust, and the like from entering. This light-shielding sheet has a notch in the center so that the cleaner 20 can move, and is adhered to the inside of the frame 40 of the cartridge.

By the way, in this embodiment, since the corona discharge device is fixed to the frame of the cartridge, it is not possible to remove the corona discharge device to clean the wire like the above-mentioned corona discharge device. Therefore, in this embodiment, after the cartridge is once pulled out from the image forming apparatus main body and taken out, the wire is cleaned by reciprocating the cleaner along the slit opening of the frame of the cartridge.

FIG. 6 shows a state in which the cartridge C is partially extracted from the image forming apparatus main body. Cartridge C is a support frame
It is supported by 50 (the back side is not shown) and a rail 52 (the right side is not shown) attached to the support frame 50.
The rail 52 engages a guide portion 53 (not shown on the right side) formed on a frame on the main body side so that the cartridge C can be stored in the main body device so as to be slidable in the directions of arrows B1 and B2. There is.

Here, in order to detach the cartridge C from the main body of the image forming apparatus, from the state where the cartridge C is mounted on the main body, the handle 51 of the support frame 50 is pulled out in the direction of the arrow B1, and the cartridge C is completely pulled out. The cartridge C is removed upward from the support frame 50. On the other hand, in order to mount the cartridge C on the main body of the image forming apparatus, the cartridge C is supported by the support frame 50.
Then, the support frame 50 may be pushed in the direction of arrow B2.

The support of the cartridge C is not limited to the above, but a rail portion is formed on the frame of the cartridge C, and a guide portion that engages with the rail portion is provided on the main body device side, so that the cartridge C is directly attached to the main body device. It may be configured to be attached and detached.

Further, the cleaner 20 of the corona discharger is placed at the front end of the slit opening 40a of the cartridge C when not in use as shown by the solid line in FIG.
In this embodiment, this position is the home position of the cleaner 20. Further, this position is at least a position that does not affect the charging action of the corona discharge device.

By the way, after removing the cartridge C from the main body device and cleaning the wire with the cleaner 20, if the cleaner 20 is not in the home position but in the position shown by the chain double-dashed line 20 'in FIG. If it has been attached to the apparatus, as in the case of the above-described embodiment, the disadvantage that charging unevenness occurs in the portion where the cleaner 20 is placed occurs.

Therefore, in this embodiment, a stopper 55 that engages with the knob portion 22 of the cleaner 20 is provided on the frame 54 on the main device side. The stopper 55 is provided inside the side plate of the main body of the image forming apparatus. Therefore, even if the cleaner C is installed in the main body apparatus with the cleaner 20 placed in the position shown by the chain double-dashed line 20 'in FIG. 6, the cartridge C is pushed in the direction of the arrow B2. Accordingly, the knob portion 22 of the cleaner 20 is changed to the two-dot chain line 2 in FIG.
Abut the stopper 55 as shown by 0 ″ and remove the cleaner 20
Movement is regulated. Therefore, as the cartridge C is inserted into the main body device, the cleaner 20 is moved relative to the corona discharge electrode in the direction B1 opposite to the insertion direction of the cartridge C, and is relatively moved to a predetermined home position. Returned to. Therefore, no matter where the cleaner 20 is placed, the cleaner 20 can be relatively moved to the home position that does not affect the charging action as the cartridge C is inserted into the main body device.

Therefore, the above-mentioned inconvenience does not occur. Further, since the stopper 55 is provided inside the side plate of the main body of the image forming apparatus, the portion of the cartridge projecting outward from the side plate is small, so that the length of the image forming apparatus can be shortened.

Incidentally, when the cleaner 20 is at the home position, the cleaning portion of the cleaner 20 is separated from the wire as in the corona discharge device described in FIGS. 2 and 3 above. As a result, an excessive pressing force does not act on the wire, and uniform charging can be performed.

By the way, as a material for the cleaning portion of the cleaner described in the above-mentioned embodiment, a flexible material such as felt is preferable, but it is required that it has ozone resistance and no fluffing, and is made of polyester fiber or polyurethane fiber. Felt is preferred. Further, since the dirt of the wire due to the additive of the toner, especially silica or the like is hard and hard to be removed, the sandpaper 25a (# 100
(About 0 or more) may be provided and applied to the wire, and the felt material 25b may be provided before and after the wire to wipe off the scraped powder. Further, the felt may be folded and the wire may be sandwiched in order to improve the cleaning.

(Effects of the Invention) As described above, according to the present invention, an operator can perform cleaning by a simple operation without directly touching the corona discharge electrode. Also, by providing a stopper, it is possible to reliably prevent forgetting to return the cleaner to the home position. The length of the image forming apparatus can be shortened because it is possible to reduce the portion protruding outward from the side plate of the image forming apparatus.

[Brief description of drawings]

FIG. 1 is a schematic diagram of an image forming apparatus showing a first embodiment of the present invention. FIG. 2 is a schematic cross-sectional view of the vicinity of the corona discharge device showing the first embodiment of the present invention. FIG. 3 is a schematic sectional view of the vicinity of a corona discharge device showing the first embodiment of the present invention. FIG. 4 is a schematic perspective view of an image forming apparatus showing a second embodiment of the present invention. FIG. 5 is a schematic cross-sectional view of the vicinity of a corona discharge device showing a second embodiment of the present invention. FIG. 6 is a perspective view showing a state in which the cartridge is partially extracted from the image forming apparatus main body. FIG. 7 is a sectional view showing a modified example of the cleaner. Symbol description 1 …… Image carrier 10 …… Corona discharge device 20 …… Cleaner 36,55 …… Stopper C …… Cartridge

Claims (4)

[Claims] 1. An image forming apparatus in which a corona discharge device having a cleaning means for cleaning a corona discharge electrode is attachable / detachable at an operating position, wherein the corona discharge is performed when the cleaning means is not at a predetermined position with respect to the corona discharge device. When the apparatus is mounted in the operating position, it has stopper means that comes into contact with the cleaning means and moves the cleaning means to the predetermined position, and the stopper means is provided inside the side plate of the image forming apparatus main body. A characteristic image forming apparatus. 2. An image forming apparatus in which a cartridge including an image carrier and a corona discharge device that has a cleaning unit that cleans a corona discharge electrode and applies a discharge to the image carrier is detachable in an operating position. When the cartridge is not in the predetermined position with respect to the corona discharge device, when the cartridge is mounted in the operating position, it has a stopper means that comes into contact with the cleaning means to move the cleaning means to the predetermined position. The image forming apparatus, wherein the stopper means is provided inside the side plate of the image forming apparatus body. 3. A cartridge which can be attached to and detached from an operating position of an image forming apparatus, and which comprises an image carrier and a corona discharge device having a cleaning means for cleaning a corona discharge electrode to discharge the image carrier. A cartridge provided with the stopper means provided inside the side plate of the main body of the image forming apparatus when the cartridge is mounted in the operating position when the cleaning means is not in a predetermined position with respect to the corona discharge device. A cartridge which is brought into contact with and moves the cleaning means to the predetermined position. 4. The cartridge according to claim 3, wherein the cartridge has a developing means for developing the image bearing member with toner.