JPH08220848A - Cleaning device for contact electrifying member - Google Patents

Abstract

PURPOSE: To prevent a mechanical life from being shortened and image quality from being deteriorated by providing plural cleaning systems for a cleaning member. CONSTITUTION: A foreign matter passing through a cleaning device adheres to a photoreceptor 11 again. Since it adheres to the cleaning member 107 press- contacting with an electrifying roller 104 again, the surface staining of the roller 104 is reduced, thereby obtaining a soft cleaning function. By energizing a solenoid 10, the cleaning member 107 is drawn right and left. Then, the roller 104 is rotated but the cleaning member 107 stops the rotation, and the surface of the roller 104 is cleaned. This case is hard cleaning because the roller 104 is rubbed. Thus, the member 104 is cleaned by ordinarily selecting the soft cleaning system to fulfill the mechanical life and selecting the hard cleaning system in every fixed period in the case of the foreign matter adhering without being completely removed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus for uniformly charging an image carrier, exposing a charged surface to form a latent image, and developing the latent image. The present invention relates to a cleaning device for a contact charging member for electrically charging or for transferring a developed image appearing on an image carrier by development to a transfer paper.

[0002]

2. Description of the Related Art The above-mentioned contact charging member is in contact with or very close to an image carrier, and when the image carrier is uniformly charged, foreign matters such as transfer residual toner on the image carrier are carried on the image carrier. Although it is removed by a cleaning device that cleans the body surface, some foreign substances pass through the cleaning device, and the contact charging member becomes dirty. When the contact charging member is used for transfer charging, foreign matter such as a toner on the image carrier after the transfer paper has passed adheres to the contact charging member.

In order to remove dirt on the contact charging member, Japanese Patent Laid-Open No. 3-130787 discloses a charging roller provided with a cleaning means.

[0004]

However, the cleaning member for cleaning the charging roller is brought into contact with the charging roller under a certain condition, while the charging roller is contaminated depending on operating conditions, operating time and the like. However, under certain cleaning conditions, it is not possible to deal with the problem, which causes deterioration of image quality.

The cleaning conditions must be determined so that the charging roller surface will not be excessively scratched or uneven, and that the charging roller surface will not be deposited and deposited. Are not satisfied, the charging roller is scratched, and the cleaning ability is too weak to satisfy the requirements, it is very difficult to satisfy both requirements.

The present invention is usually carried out under cleaning conditions that satisfy the mechanical life, and if the foreign matter adhered without being completely cleaned, the contact charging member can be cleaned by hard cleaning at regular intervals to shorten the life. There is provided a cleaning device for a contact charging member that does not deteriorate the image quality. Further, by automatically changing the cleaning condition of the contact charging member, the convenience is further improved and the deterioration of the mechanical quality due to forgetting to switch the cleaning condition is prevented.

[0007]

SUMMARY OF THE INVENTION The present invention provides a cleaning device for a contact charging member, which comprises a contact charging member that is in contact with or close to an image carrier and a cleaning member for cleaning the surface of the contact charging member. The cleaning member has a plurality of cleaning methods.

[0008]

[Operation] By selecting one of a plurality of cleaning methods,
The contact charging member is cleaned under the cleaning condition determined by the selected cleaning method. Normally, a cleaning method that satisfies the mechanical life is selected to clean the contact charging member.For foreign substances that have not been completely cleaned, the cleaning method that meets hard cleaning conditions is selected at regular intervals. If the contact charging member is cleaned in this manner, the life of the contact charging member is not shortened, and the image quality is not significantly deteriorated. One embodiment of the present invention is provided with an automatic switching means for switching the cleaning condition of the contact charging member, and normally sets a cleaning method that satisfies the mechanical life, and responds to a command input at regular intervals and / or. The automatic switching means switches to a cleaning method that meets hard cleaning conditions. As a result, convenience is further improved, and deterioration of machine quality due to forgetting to switch cleaning conditions is avoided.

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

[0010]

1 shows an outline of a copying machine equipped with a contact charging device 100 equipped with a cleaning device according to an embodiment of the present invention. The copying machine shown in FIG. 1 is a copying machine capable of two-color overlapping recording (two-color color copying).
A single-color recording mode of red, blue or blue, and a two-color recording mode of black + red or blue recording can be selectively reproduced. Although there is only one 11, a contact charging device (first charging charger) 100, a first exposure device 14, and a first developing device 15 for black recording.
And a second visible image forming unit for recording red or blue, which includes a second charging charger 16, a second exposure device 17, and a second developing device 18. First
The developing device 15 stores a black toner, and the second developing device 18 stores a red or blue toner.

The photosensitive drum 11 is rotationally driven by a main motor (not shown), and first, light is emitted by a static eliminator 12 including a static eliminator lamp and a static eliminator to eliminate static electricity, so that the surface potential is 0V to 100V. It becomes the reference potential of. Next, the photosensitive drum 11 is uniformly charged by the first charging charger 100 and has a surface potential of -85.
It will be around 0V.

The recording image light modulated by the digital recording image information (black image information) is projected from the laser exposure device (not shown) onto the reflecting mirror 141 of the exposure system 14, and then the photosensitive drum 11 is exposed. Then, the first electrostatic latent image is formed on the photosensitive drum 11. Laser light 14
The surface potential of the portion irradiated with 2 becomes 0 to -100V. The first electrostatic latent image is developed with a black toner by the first developing device 15 to become a black visible image. The first developing device 15
During the developing operation, the developing rollers 151, 152, the stirring roller 153, and the stirring blades 154 are rotationally driven, and the developer including the black toner and the carrier is stirred by the stirring roller 153 and the stirring blades 154 and sent to the developing rollers 151, 152. The black toner is transferred from these rollers 151 and 152 to the potential portion of 0 to -100V of the photosensitive drum 11.

A part of the developer on the developing roller 151 is scraped off by a doctor blade 156 and adjusted to a constant amount, and then the photosensitive drum 11 and the developing sleeves 151,1.
After passing between 52 and 52, it returns to the inside of the developing container 155, and is again stirred by the stirring roller 153 and stirring blade 154 and conveyed. Further, the developing sleeve 1 is formed by the doctor member 156.
The developer scraped off from above the 51 is separated by the separator 157.
Through the stirring roller 153 and the stirring blades 154 to be stirred again.
1,152. While the developer circulates in this manner, the electrostatic latent image on the photoconductor drum 11 is developed by the developer passing between the photoconductor drum 11 and the developing rollers 151, 152. Further, black toner is replenished to the developer in the developing container 155 from the toner replenishing section 158. A developing bias voltage of about -600 V is applied to the developing sleeves 151, 152 from a power source.

Charging, static image formation and development for the black recording described above are performed only when the black monochromatic recording mode or the two-color recording mode is selected by the operation unit, and monochromatic color recording ( It is not executed when the (red or blue) mode is selected on the operation unit.

When the two-color recording mode or the single-color color recording mode is selected, the photosensitive drum 11 is set to the second
The electrostatic charger 16 is charged by the charging charger 16, is exposed to the image light by the exposure device 17, forms an electrostatic latent image, and is developed by the second developing device 18 with a red toner or a blue toner.

After passing through the second developing device 18, the photoconductor drum 11 is neutralized by the pre-transfer static eliminator 19 and is transferred by the transfer belt 201 of the transfer device 20.
The toner image on 1 is transferred to the recording paper fed from the paper feeding device. The recording paper is fed from the paper feeding device to the registration roller 2
1 and the registration roller 21 sends the recording paper to the transfer device 20 at a timing such that the front end of the toner image on the photosensitive drum 11 and the front end of the recording paper coincide with each other.

The transfer device 20 includes a transfer belt 201, and a driving roller 202 and a driven roller 203 that support the transfer belt 201.
A bias roller 204 that contacts the back surface of the transfer belt 201, and a cleaning device 205. The drive roller 202 is connected to the main motor and rotationally drives the transfer belt 201 when the main motor rotates. The transfer belt 201 is pressed against the photosensitive drum 11 only at the time of transfer by a belt contacting / separating mechanism (not shown), and is separated from the photosensitive drum 11 when the transfer is completed. When recording paper is sent from the registration roller 21 to the transfer device 20, the bias roller 204 is charged with black toner and color toner (red toner or blue toner) on the photosensitive drum 11 from a high voltage power source (not shown). A transfer voltage having a polarity opposite to the polarity is applied, and the toner image is transferred onto the recording paper at the nip portion (contact surface) between the photoconductor drum 11 and the transfer belt 201.

The transfer belt 201 changes the transfer voltage according to its transfer voltage.
The recording paper is adsorbed and conveyed, whereby the recording paper is separated from the photosensitive drum 11. If the recording paper is the photosensitive drum 1
If it is not separated from 1, the photosensitive drum 11 is separated by the separation claw 22.

The recording paper conveyed by the transfer belt 201 is
The fixing device (not shown) heats and pressurizes. As a result, the toner image is fixed (fixed) on the recording paper. This recording paper is discharged to the outside of the copying machine. The transfer belt 201 is cleaned by the cleaning device 205 after the recording paper is separated. That is, the residual toner on the transfer belt 201 is scraped off by the brush 205a and the cleaning blade 205b.

The photosensitive drum 11 is cleaned by the cleaning device 23 after the recording paper is separated. That is, the residual toner is removed by the brush 231 and the cleaning blade 232, and the process moves to the next image forming step again.

FIG. 2 is an enlarged view of the contact charging device 100. 2A is an enlarged view of the left side surface of the apparatus 100 when viewed from the developing device 15 (FIG. 1) side, FIG. 2B is an enlarged vertical cross section of the left end portion, and FIG. The vertical cross section of the right end portion is enlarged and shown, and (d) is the enlarged right side surface. The top plate 101 extending in the x direction has guide plates 102L1, 102L2 and 102R1, 10 on its left and right ends.
2R2, and they have slide blocks 103L,
106L, 103R, and 106R are mounted to be movable to some extent in the z direction.

A shaft of a contact charging type charging roller 104 is rotatably supported by blocks 103L and 103R via bearings, and compression coil springs 102L1, 102L2 and 102R1, 102R2 are supported.
Pushes the blocks 103L and 103R in the direction toward the photoconductor 11, so that the charging roller 1 is caused by these spring forces.
Reference numeral 04 is pressed against the photoconductor 11 and is rotated by the rotation of the photoconductor 11. In addition, the photoconductor 11
A voltage is applied to the charging roller 104 by a DC power source (not shown) at the timing of charging the photosensitive member 11 to charge the photosensitive member 11.

A shaft of a cleaning member 107 is supported by the blocks 106L and 106R so as to be rotatable and movable in the x direction, and a compression coil spring 108 is provided.
Since L1, 108L2 and 108R1, 108R2 push the blocks 106L and 106R in the direction toward the blocks 103L and 103R, the cleaning member 107 is pushed against the charging roller 104 by these spring forces, and in the state shown in FIG. , Charging roller 104
Is rotated by the rotation of.

The cleaning member 107 is attached to the body 1. Referring to FIG. 2 (b), a ring-shaped groove 2L is cut all around the left end portion of the body 1, and an incomplete ring-shaped groove is formed next to the groove 2L. The groove 3L is cut. Referring to FIG. 2 (c), a similar ring-shaped groove 2R and incomplete ring-shaped groove 3R are cut at the right end of the body 1.

Referring to FIG. 2 (b), a cap 5 is provided at the left end of the shaft of the cleaning member 107 so that the cap 5 slides with respect to the rotation of the shaft but does not move with respect to the linear movement in the x direction. It is engaged in a relationship of moving integrally, and a pin 6 stands on this cap 5. A lever that can rotate around the pin 8
One end of 7 is engaged with the pin 6, and the other end is engaged with the pin 9 standing on the plunger of the solenoid 10.

The solenoid 10 has a plunger return spring built-in. While the electric coil is not energized, the repulsive force of the return spring causes the plunger to be pushed to the left as shown in FIG. 2 (b). By this, pin 9, lever
The cleaning member 107 is pushed rightward via the pin 7, the pin 6 and the cap 5. When pushed in this way to the right, the ring-shaped grooves 2L (left end portion) and 2
To match the R (right end) and enter inside them,
The upper ends of the stoppers 4R and 4L that are highly flexible in the x direction and hard and strong in the y direction are fixed to the top plate 101.

While the solenoid 10 is not energized, the pressing force of the pressing spring in the solenoid 10 and the stoppers 4R and 4L are fitted in the ring-shaped grooves 2L and 2R, so that the cleaning member 107 is It is in the position pushed to the right as shown in FIGS. 2B and 2C, and is stable there. A cross section of the ring-shaped groove 2L at this time is shown in FIG. Since the stopper 4R does not restrain the rotation of the cleaning member 107, the cleaning member 107 is rotated by the rotation of the charging roller 104. Foreign matter such as transfer residual toner on the photoconductor 11 is removed by the cleaning device 23 (FIG. 1).
Although removed from the surface, some foreign substances pass through the cleaning device 23, and some foreign substances are re-deposited on the photoconductor 11 from the cleaning device 23. These reach the charging roller 104 pressed against the photoconductor 11 and stain the surface of the charging roller 104 to reduce the charging performance of the charging roller 104, but here, the cleaning member 107 pressed against the charging roller 104. The surface of the charging roller 104 is less contaminated because of reattachment to the surface of the charging roller 104. In this cleaning function, since the cleaning member 107 rotates together with the charging roller 104, there is substantially no relative slippage, the mechanical load on the charging roller 104 is small, and the charging roller 104 is small. The degree to which the la 104 is worn is extremely low. That is, "soft" cleaning. However, to that extent, the effect of removing foreign matter that is relatively strongly or firmly attached is low.

When the solenoid 10 is energized, the plunger is pulled against the repulsive force of the built-in return spring, whereby the lever 7 is rotationally driven in the clockwise direction and the cleaning member 107 is pulled to the left. . At this time, the stopper 4L,
4R is bent in the x direction, and the ring-shaped flanges between the grooves 2L / 3L and between the grooves 2R / 3R of the body 1 are stopped by the stoppers 4L,
Go through the lower end of 4R to the left, and clean member 1
07 moves to the left as shown in FIG. When the state of moving to the left (energization of the solenoid 10) is continued, the non-grooved portions of the imperfect grooves 3L and 3R of the core body 1 of the cleaning member 107 that is rotating with the charging roller 104. As shown in FIG. 4B, the stoppers 4L and 4R prevent the cleaning member 107 from rotating together with the stoppers 4L and 4R. This allows
The charging roller 104 rotates, but the cleaning member 107
Stops rotating and cleaning member 10 stops rotating
In step 7, the surface of the charging roller 104 that continues to rotate is rubbed to clean the surface of the charging roller 104. The cleaning member 104 is charged with the cleaning roller 104.
Since 7 is rubbed, a considerable mechanical force acts on the foreign matter, and the effect of removing the foreign matter that is relatively strongly or firmly attached is high. However, the degree to which the charging roller 104 is worn is relatively high. That is, a "hard" clear
It is Ning.

When the solenoid 10 is de-energized, the return spring built into the solenoid 10 pushes out the plunger and the cleaning member 107 returns to the left position (FIG. 2).
That is, when the solenoid 10 is not energized, "soft" cleaning is set, and when the solenoid 10 is energized, "hard" cleaning is set.

As described above, since the "hard" or "soft" cleaning is realized depending on whether or not the solenoid 10 is energized, the cleaning method (hard or soft) is selected. It is possible.

In the above-described embodiment, the solenoid 107 is energized / de-energized by a signal from a controller (not shown). Since the hard is set only while the signal is on (solenoid energization), and when the power is off, it naturally returns to soft, which reduces mode change work. In addition, there is no possibility of leaving the hard setting for a long time due to forgetting to change the setting.

In the above embodiment, the solenoid 107 is provided so that the software / software can be automatically operated (that is, by a control signal).
Although the hard is set, in a simpler mode, the solenoid 107 and the lever 7 can be omitted, and the cap 5 can be manually set to the soft / hard position. For example, when the cap 10 is pulled to the left without the solenoid 10 and the lever 7 in FIG. 2, the hard setting shown in FIG. 3 (however, the solenoid 10 and the lever 7 are not provided) is obtained. Cap 5 with hard setting (Fig. 3)
Press to the right to enter the software settings shown in FIG.

Further, in the above embodiment, the contact charging device 100 is used as a charger for uniformly charging the photoconductor, but it is also possible to use this in place of the transfer charger. It is also possible to use the cleaning section of the contact charging device 100 for cleaning the transfer belt. That is, the charging roller 104 of the contact charging device 100 described above may be replaced with a transfer belt.

[0034]

EFFECTS OF THE INVENTION Normally, a cleaning method which is a soft cleaning condition that satisfies the mechanical life is selected to clean the contact charging member, and the foreign matter adhered to the contact charging member cannot be completely cleaned. If the cleaning method is selected and the contact charging member is cleaned, the life of the contact charging member is not shortened and the image quality is not significantly deteriorated.

[Brief description of drawings]

FIG. 1 is a side view showing the outline of the mechanism of a copying machine equipped with an embodiment of the present invention.

FIG. 2 is an enlarged view of the contact charging device 100 shown in FIG. 1 in a state where the solenoid 10 is not energized, (a) is a left side view (a view taken along the line AA of (b)), (b). Is a vertical cross-sectional view of the left end portion, (c) is a vertical cross-sectional view of the right end portion, and (d) is a right side view (a view from the arrow D-D of (c)).

FIG. 3 is an enlarged view of the contact charging device 100 shown in FIG. 1 in a state where the solenoid 10 is energized. (A) is a left side view (a view taken along the line AA of (b)), (b) is FIG. 5 is a vertical sectional view of a left end portion, (c) is a vertical sectional view of a right end portion, and (d) is a right side view (a view taken along the line D-D of (c)).

4 is an enlarged cross-sectional view of the cleaning member 107, (a) showing an enlarged cross-section of the ring 2L portion in the state shown in (b) of FIG. 2, and (b) of FIG. The enlarged cross section of the ring 3L part in the state shown to b) is shown.

[Explanation of symbols]

1: Body 2L, 2R: Ring-shaped groove 3L, 3R: Incomplete ring-shaped groove 4L, 4R: Stopper 5: Cap 6, 8, 9: Pin 7: Lever 10: Solenoid 11: Photoconductor 12: Static eliminator 14: Exposure system 15: First developing device 16: Second charging charger 17: Exposure device 18: Second developing device 19: Pre-transfer static eliminator 20: Transfer device 201: Transfer belt 202: Driving roller 203: driven roller 204: bias roller 205: cleaning device 208: transfer device frame 21: registration roller
LA 22: Separation claw 23: Cleaning device

Claims (2)

[Claims] 1. A cleaning device for a contact charging member, comprising: a contact charging member that is in contact with or close to an image carrier and a cleaning member for cleaning the surface of the contact charging member. A cleaning device for a contact charging member, which has: 2. The cleaning device for a contact charging member according to claim 1, wherein the cleaning method is automatically changed according to a predetermined period.