JPH05265307A - Cleaning method for electrostatic charging roller and device for the method - Google Patents

Abstract

PURPOSE:To improve the uniformity of an electrostatic charge by removing the foreign matter of the surface of an electrostatic charging roller. CONSTITUTION:On the upstream side in the rotational direction of the electrostatic charging roller 102, than a position where the electrostatic charging roller 102 is in contact with a photosensitive body 101, a cleaning member 103 constituted by radially attaching a Teflon brush 103b to a bar-like supporting member 103a, is brought into contact with the photosensitive body 101 and the electrostatic charging roller 102, and the cleaning member 103 is slid in the longitudinal direction of the electrostatic charging roller 102.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a charging roller cleaning method and apparatus for removing foreign matters adhering to the surface of the charging roller. BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a charging roller cleaning method and apparatus for sliding foreign matter on a surface of a charging roller to remove foreign matter.

[0002]

2. Description of the Related Art In an electrophotographic image forming apparatus, a corona charger that charges a photosensitive member by corona discharge is widely used. However, a corona discharger generally requires a voltage of 5 KV or more applied to the discharge wire,
There is a problem in terms of safety and economy, and ozone generated during discharge is a problem.

On the other hand, recently, for example, a roller charger (contact charger) using a charging roller has been put into practical use. The roller charger charges the photosensitive member by discharging through a gap existing between the charging roller and the surface of the photosensitive member. Generally, the charging roller is a conductive rubber roller and is necessary for discharging. Since high voltage cannot be applied,
A resistance layer for preventing leakage is provided on the surface of the conductive rubber roller. This roller charger has the advantage that it requires a lower voltage than the corona charger and generates less ozone, but it has the drawback of being less reliable in terms of charging uniformity.

Factors that greatly affect the uniformity of charging include structural factors such as the uniformity of the resistance layer provided on the surface of the charging roller, and stains on the surface of the charging roller and the photosensitive member. Generally, dirt on the surface of the photoconductor is caused by transfer of foreign matter such as toner on the surface of the photoconductor, and the area where the foreign matter is transferred is not properly discharged, resulting in uneven charging.
Therefore, for example, as in the “charging device” disclosed in Japanese Patent Laid-Open No. 3-101768, by contacting a sponge material to the surface of the charging rotator (charging roller), the surface of the charging rotator There is something that is being cleaned.
The use of the sponge material in the publication is, for example, in the case of using a film-like sheet or the like, it is difficult to follow the surface of the charging roller, so that the cleaning property is poor, and the cleaning property is improved. This is because if the sheet is strongly pressed against the charging roller, the surface of the charging roller may be damaged or the rotation of the charging roller may be hindered.

[0005]

However, according to the cleaning method used in the "charging device" of Japanese Patent Laid-Open No. 3-101768, cleaning is performed by bringing a sponge material into contact with the charging roller. Since a gap may be formed between the charging roller and the sponge material due to the worn state of the sponge material, partial chipping, and the like, foreign matter on the surface of the charging roller cannot always be removed, which causes uneven charging. It was

The present invention has been made in view of the above, and it is an object of the present invention to improve the uniformity of charging by reliably removing foreign matter on the surface of the charging roller.

[0007]

In order to achieve the above object, the present invention provides a method of cleaning a charging roller for removing foreign matter adhering to the surface of the charging roller, wherein a cleaning member in contact with the charging roller is The present invention provides a method for cleaning a charging roller that slides in the longitudinal direction of the.

In order to achieve the above object, the present invention provides a charging roller cleaning device for removing foreign matter adhering to the surface of the charging roller, wherein the charging roller rotates more than the position where the charging roller contacts the photosensitive member. Provided is a cleaning device for a charging roller, which comprises a cleaning member arranged in contact with a charging roller and a photoconductor on the upstream side with respect to the direction, and a drive means for sliding the cleaning member in the longitudinal direction of the charging roller. It is a thing.

In order to achieve the above object, the present invention provides a charging roller cleaning device for removing foreign matter adhering to the surface of the charging roller, wherein the charging roller rotates more than the position where the charging roller contacts the photosensitive member. A cleaning member arranged in contact with the charging roller and the photoconductor on the upstream side with respect to the direction, driving means for sliding the cleaning member in the longitudinal direction of the charging roller, and a predetermined mode is input via the input means. The present invention provides a cleaning device for a charging roller, which comprises a control means for executing drive control of the drive means when the cleaning is performed.

In order to achieve the above object, the present invention provides a charging roller cleaning device for removing foreign matter adhering to the surface of the charging roller, wherein the charging roller rotates more than the position where the charging roller contacts the photosensitive member. A cleaning member disposed in contact with the charging roller on the downstream side of the direction,
(EN) A cleaning device for a charging roller, comprising a driving means for sliding a cleaning member in the longitudinal direction of the charging roller.

In order to achieve the above object, the present invention provides a charging roller cleaning device for removing foreign matter adhering to the surface of the charging roller, wherein the charging roller rotates more than the position where the charging roller contacts the photosensitive member. A cleaning member disposed in contact with the charging roller on the downstream side of the direction,
When a predetermined mode is input through the drive means for sliding the cleaning member in the longitudinal direction of the charging roller and the input means,
The present invention provides a cleaning device for a charging roller, which is provided with a control means for executing drive control of the drive means.

In the above construction, it is desirable that the cleaning member is detachably arranged.

[0013]

In the method and apparatus for cleaning a charging roller according to the present invention, a cleaning member brought into contact with the charging roller is slid in the longitudinal direction of the charging roller to remove foreign matter adhering to the surface of the charging roller.

[0014]

Embodiments of the present invention will be described below in the order of the first embodiment, the second embodiment and the third embodiment with reference to the drawings. 1A and 1B are explanatory views showing the arrangement position and the shape of the cleaning member according to the first embodiment, and FIG. 2 is a control system of an image forming apparatus to which the first embodiment is applied. 3 is a block diagram showing a schematic configuration of FIG.

As shown in FIG. 2, the control system of the image forming apparatus includes a main control unit 201 that controls the entire apparatus.
A storage unit 202 that stores various conditions in image formation such as programs and copy modes that are currently set, an optical control unit 203 that controls an optical system (not shown) that reads a document image, and an image forming system The AC control unit 204 that executes the control of 1) and the operation control unit 206 that executes the control of the operation panel 205 for setting various copy modes are connected. Reference numeral 207 denotes various sensors such as a sensor for detecting the toner concentration in the developing unit (not shown),
Reference numeral 208 is a group of solenoids, clutches, and motors for controlling the operation of the apparatus.

The optical control unit 203 includes a lens of an optical system, a lens motor for changing the optical arrangement of mirrors, a scanner motor for driving the optical system to scan an original, and an original placed on a contact glass. APS sensors 1 and 2 for detecting the size are connected.

The AC control unit 204 includes an exposure lamp for irradiating the original with light, a fixing heater for supplying heat to a fixing unit for fixing the toner image transferred on the recording paper, and a main motor for driving the photoconductor and the like. Connected to are a developing motor that drives the developing sleeve of the developing unit, a conveying motor that supplies power for conveying the recording paper on which the toner image has been transferred, and a paper feeding motor that takes out the recording paper from the paper feeding cassette and conveys it. Has been done.

The operation of the above configuration will be described. The image forming conditions input by operating the keys on the operation panel 205 are output to the main control unit 201 via the operation control unit 206. Main control unit 201
Outputs a control signal to each control unit based on the input image forming condition, each detection result output from the sensors 207, and each control unit receives the control signal input from the main control unit 201. According to the above, various motors are driven. The main control unit outputs a control signal to each control unit and also drives a solenoid, a clutch, etc. at a predetermined timing,
Manage the process of image formation.

Next, the first embodiment will be described. As shown in FIG. 1A, the charging roller 10 according to the first embodiment is used.
The charging roller 10 is located at a position more than the position where 2 contacts the photoconductor 101.
2, a cleaning member 103 that is in contact with the photoconductor 101 and the charging roller 102 on the upstream side with respect to the rotation direction of
And a case 104 that covers the charging roller 102 and the cleaning member 103. The cleaning member 103 includes a photoconductor 101 and a charging roller 102.
In order to remove foreign substances adhering to the surface, it is a roller-shaped support member 103a in which a Teflon brush 103b is radially attached to a rod-shaped support member 103a, and as shown in FIG. 1 (b), the brush 103b is a photosensitive member. It covers the portion of the charging roller 102 that charges the image area of the body 101.

In the first embodiment, the cleaning member 103 and the case 104 are attached to the image forming apparatus together with the charging roller 102 and a charging unit (not shown).
Is attached to the image forming apparatus. Cleaning member 1
03 and the case 104 are configured to be easily removable from the charging unit. Specifically, in FIG. 1 (b),
The lower end is inserted into the hole on the back side plate when it is mounted on the image forming device of the charging unit, and the other end is charged by being clamped in the groove provided on the front side plate. It is attached to the unit, and the case 104 is attached to the charging unit with screws.

Further, the end portion of the cleaning member 103 inserted into the side plate on the back side of the charging unit engages with the cam mechanism to which power is transmitted from the main motor when the charging unit is mounted on the image forming apparatus. Cleaning member 10
The upper end of 3 is configured such that pressure is applied toward the inside of the image forming apparatus (that is, the cam mechanism) by the spring member.

The operation of the above configuration will be described. The power of the main motor is transmitted to the photoconductor 101 via a gear and a clutch to rotate, and the charging roller 102 rotates following the rotation of the photoconductor 101. The cleaning member 103 slides in the longitudinal direction of the charging roller 102 by a cam mechanism to which the power of the main motor is transmitted via a clutch.

Next, a cleaning performance test conducted using the image forming apparatus to which the first embodiment is applied will be described. The image forming apparatus to which the first embodiment is applied has a function added so that various cleaning performance tests can be performed. The cleaning performance test is performed in three cases, that is, when the cleaning member 103 is removed (case 1), when the cleaning member 103 is not slid (case 2), and when the cleaning member 103 is slid (case 3), The cleaning performance was evaluated based on the stains on the surface of the charging roller 102 during the normal image formation and the occurrence of background stains due to uneven charging. Table 1 shows the cleaning performance test results.

[0024]

[Table 1]

As shown in Table 1, in both case 1 and case 2, the charging roller 102 had vertical streaks, but in case 3, uniform stains were generated on the entire surface. Since a large amount of toner adheres to the portion of the vertical streaks, the difference in charging potential from other portions becomes large. Therefore, Case 3 has a far better result than the other cases in the number of background stains caused by uneven charging.

Here, in the case 3, when the cleaning member 103 is dirty at the time of 15,000 sheets, a large amount of toner adheres to the portion in contact with the photoconductor 101 and a small amount of toner adheres to the portion in contact with the charging roller 102. there were.
This means that the first embodiment has an effect of preventing uneven charging due to the toner attached to the photoconductor 101. When the cleaning member 103 was cleaned and reused, the result was almost the same as before.

As described above, by sliding the cleaning member 103 in contact with the charging roller 102, foreign matter on the surface of the charging roller 102 can be removed uniformly and efficiently, and uneven charging can be suppressed. be able to. Further, by uniformly removing the foreign matter on the surface of the charging roller 102, it is possible to reduce the degree of uneven charging, and it is particularly effective in suppressing the occurrence of scumming.

In case 3 shown in Table 1, the cleaning member 103 is slid while the photosensitive member 101 is rotating.
02 Surface stains occur at 3000 sheets and background stains occur at 5000 sheets. From this result, the charging roller 102
It can be seen that the cleaning can be done regularly.

In the first embodiment, a cleaning mode function is further provided so that the charging roller 102 can be regularly cleaned. The cleaning mode is set via the operation panel 205. When the cleaning mode is set, the cleaning member 103 is slid while the photoconductor 101 is idly rotated to slide the charging roller 1
No. 02 cleaning was performed. Charging roller 10
The cleaning frequency of No. 2 was set to every 5000 sheets based on the result of Case 1 shown in Table 1, and the cleaning result was examined by changing the cleaning time.

As a result, it was found that the cleaning period of the charging roller 102 is about 1 minute for every 5000 sheets of image formation. Since the image forming apparatus to which this embodiment is applied uses the positive developing method, the cleaning member 103 is attached only when cleaning the charging roller 102. This is because in the case of the positive development method, the polarity applied to the charging roller 102 and the polarity of the toner are different, so that the charging roller 102 does not adsorb the toner from the cleaning member 103. In the image forming apparatus using the reversal development method,
Since the polarity applied to the charging roller 102 and the polarity of the toner are the same, the cleaning member 103 may be separated when the charging roller 102 is not cleaned.

As described above, depending on the developing method of the image forming apparatus, the cleaning member 103 may have to be removed from the apparatus, and the cleaning member 10 may be removed.
It is desirable that the cleaning member 103 can be easily attached and detached also from the viewpoint of labor when replacing the cleaning member 103. Further, in order to prevent the toner attached to the cleaning member 103 from scattering, it is desirable that the cleaning member 103 can be attached and detached without giving much vibration.

In the first embodiment, the cleaning member was manually slid on the charging roller 102 to perform cleaning. As a result, it was easy to use a cleaning member having a length about half that of the charging roller 102.

Next, the second embodiment will be described. In the second embodiment, in the image forming apparatus to which the first embodiment is applied, the cleaning member is arranged downstream of the contact position of the charging roller with the photoconductor in the rotation direction of the charging roller. For this reason, the configuration of the control system of the image forming apparatus is the same as that of the first embodiment, and only the different reference numerals are changed.

FIGS. 3A and 3B are explanatory views showing the arrangement position and the shape of the cleaning member according to the second embodiment. As shown in FIG. 3A, in the third embodiment, a cleaning member 301 is arranged downstream of the position where the charging roller 102 contacts the photoconductor 101 in the rotation direction of the charging roller 102. is there. The cleaning member 301 includes a support member 301a and a brush 30 made of Teflon.
1b is attached, and as shown in FIG. 3B, the brush 301b covers the portion of the charging roller 102 that charges the image area of the photoconductor 101. The cleaning member 301 is mounted on the charging unit together with the charging roller 102 as in the first embodiment. At this time, the rail member 301c is inserted along the groove provided in the plate member of the charging unit. It is attached. In FIG. 3B, the rail member 30
The upper end of 1c is bent so that the cleaning member 301 can be easily attached and held.

In the second embodiment, as shown in FIG. 3A, the cleaning member 301 is brought into contact with the charging roller 102. Therefore, in the first embodiment, the foreign matter removed from the charging roller 102 is carried on the brush 103b, but in the second embodiment, the foreign matter removed from the charging roller 102 is dropped onto the photoconductor 101. In the first embodiment, when the cleaning performance of the cleaning unit of the photoconductor 101 is low, the amount of toner that the brush 103b cannot hold immediately accumulates, and the cleaning member 103 does not need to be cleaned frequently. However, the second embodiment has an advantage that the cleaning frequency of the cleaning member 301 is smaller than that of the first embodiment under the same conditions. Therefore, it is appropriate to apply the first embodiment to an image forming apparatus having a high cleaning performance for the photoconductor 101, and to apply the second embodiment to an image forming apparatus having a low cleaning performance.

In the second embodiment, similarly to the first embodiment, the cleaning mode is set and the charging roller 102 is cleaned. As for the frequency of cleaning,
From the results shown in Case 1 of Table 1, the number of sheets was set to 3000. Further, in the second embodiment, since the toner on the surface of the charging roller 102 is dropped onto the photoconductor 101, the cleaning unit for removing the toner on the surface of the photoconductor 101 is driven during the cleaning mode.

Also in the second embodiment, good results could be obtained as in the first embodiment. In addition, about 30 seconds was sufficient for cleaning the charging roller 102 for every 3000 sheets of image formation. The second
In the first embodiment, the case is not provided as in the first embodiment. This is because the cleaning member 103 is in contact with the upstream side of the charging roller 102 in the first embodiment. This is to prevent the brush 103b from scattering the toner removed from the charging roller 102 (may be scattered leftward toward FIG. 1A). Also,
As a result of manually cleaning the charging roller 102,
Similar to the first embodiment, it was easy to use a cleaning member having a length about half that of the charging roller 102.

Next, a third embodiment will be described. The third embodiment differs from the second embodiment only in the cleaning member. As shown in FIG. 4A, the cleaning member 401 used in the third embodiment has a support member 401a on which a sponge 401 made of polyurethane foam is attached.
b is attached. Similar to the second embodiment, the cleaning member 401 has a rail member 401c (see FIG. 4B) along a groove formed in the plate member of the charging unit.
It is attached by inserting.

The third embodiment has the same effect as the second embodiment, but the brush 3 used in the second embodiment is used.
The cleaning performance of the sponge 401b was better than that of 01b. At this time, the pressure for bringing the sponge 401b into contact with the charging roller 102 showed a high cleaning performance when the contact was made lightly. Further, as the shape of the sponge 401b, by making the contact surface with the charging roller 102 small, high cleaning performance was exhibited. Therefore, regarding the cross-sectional shape of the sponge 401b,
From the viewpoint of cleaning performance and strength, it has a trapezoidal shape as shown in FIG. In addition, the charging roller 102
As a result of cleaning the
A cleaning member having a length of about 3 was easy to use.

In the first to third embodiments, the charging roller is cleaned by setting the cleaning mode. For example, the charging roller is automatically cleaned every 3000 sheets (see Table 1). The cleaning may be performed, or may be performed when the image forming apparatus is powered on. What is performed when the image forming apparatus is turned on has an effect that the time from turning on the power to starting the apparatus can be effectively used.

Further, since the charging roller generally rotates following the photosensitive member, it is desirable that the resistance of the cleaning member exerted on the charging roller is small. Therefore, since the cleaning member slides in the longitudinal direction of the charging roller, the shape of the cleaning member contacting the charging roller may be a sawtooth shape by providing a groove in the longitudinal direction of the charging roller. The member may be slid to a large extent in the longitudinal direction of the charging roller. Recently, high-performance small motors have been developed,
When a small cleaning member is used, the cost of the device according to the present invention can be suppressed by using this motor as a power source. Further, it is also effective for downsizing the apparatus, and therefore, it becomes easy to newly install the apparatus of the present invention to the image forming apparatus which already uses the charging roller.

The speed at which the cleaning member slides depends on the material and shape of the cleaning member (particularly the length in contact with the charging roller in the longitudinal direction), the shape of the charging roller,
An appropriate speed suitable for the device may be set based on the material, linear velocity, and the like. At this time, for example, the cleaning member may be slid at a high speed with a shape in which the cleaning member is in long contact with the rotation direction of the charging roller. Further, since the cleaning member that is in contact with the charging roller is worn out as it is used, it is desirable to use a mechanism that presses the cleaning member against the charging roller with an appropriate pressure. Further, the present invention can be applied not only to the charging roller but also to a charging member that moves following the photosensitive member, for example, a belt-shaped charging member.

[0043]

As described above, in the charging roller cleaning method and apparatus according to the present invention, the cleaning member brought into contact with the charging roller is slid in the longitudinal direction of the charging roller to adhere to the surface of the charging roller. Since the foreign matter is removed, the foreign matter on the surface of the charging roller can be reliably removed, and the uniformity of charging can be improved.

[Brief description of drawings]

FIG. 1 is an explanatory view showing an arrangement position and a shape of a cleaning member according to a first embodiment.

FIG. 2 is a block diagram showing a schematic configuration of a control system of the image forming apparatus to which the first embodiment is applied.

FIG. 3 is an explanatory view showing a disposition position and a shape of a cleaning member according to a second embodiment.

FIG. 4 is an explanatory view showing an arrangement position and a shape of a cleaning member according to a third embodiment.

[Explanation of symbols]

101 photoconductor 102 charging roller 103 301 401 cleaning member 103a 301a 401a support member 103b 301b brush 401b sponge 104 case 301c 401
c Rail member 201 Main control unit 205 Operation panel 204 AC control unit

Claims (6)

[Claims] 1. A method of cleaning a charging roller for removing foreign matters adhering to the surface of the charging roller, wherein a cleaning member in contact with the charging roller is slid in a longitudinal direction of the charging roller. Cleaning method. 2. A charging roller cleaning device for removing foreign matter adhering to the surface of the charging roller, wherein the charging roller is located upstream of the position where the charging roller contacts the photoconductor in the rotating direction of the charging roller. A cleaning device for a charging roller, comprising: a cleaning member arranged in contact with the photoconductor; and a driving means for sliding the cleaning member in the longitudinal direction of the charging roller. 3. A charging roller cleaning device for removing foreign matter adhering to the surface of the charging roller, wherein the charging roller is located upstream of the position where the charging roller contacts the photoconductor in the rotating direction of the charging roller. And a cleaning member disposed in contact with the photoconductor, a driving unit that slides the cleaning member in the longitudinal direction of the charging roller, and a predetermined mode of the driving unit when inputting a predetermined mode through the input unit. A charging roller cleaning device, comprising: a control unit that executes drive control. 4. A charging roller cleaning device for removing foreign matter adhering to the surface of the charging roller, wherein the charging roller is located downstream of a position where the charging roller contacts the photoconductor with respect to a rotation direction of the charging roller. A cleaning device for a charging roller, comprising: a cleaning member disposed in contact with the charging roller; and driving means for sliding the cleaning member in the longitudinal direction of the charging roller. 5. A charging roller cleaning device for removing foreign matter adhering to the surface of the charging roller, wherein the charging roller is located downstream of a position where the charging roller contacts the photoconductor in the rotation direction of the charging roller. A cleaning member which is disposed in contact with the cleaning roller, a drive unit which slides the cleaning member in the longitudinal direction of the charging roller, and a drive control of the drive unit when a predetermined mode is input through the input unit. A charging roller cleaning device, comprising: a control unit that executes the charging roller. 6. The cleaning device for a charging roller according to claim 2, 3, 4, or 5, wherein the cleaning member is detachably arranged. .