JPH10312100A - Image forming device - Google Patents

Abstract

(57) [Summary] [Problem] When the amount of residual toner is too large to be collected, an afterimage may occur, or the remaining toner which has not been completely collected may adhere to the photoconductor and cause filming. A charging brush roller charges the surface of a photoreceptor and holds a scraped lubricant between brush fibers to apply the lubricant to the photoreceptor. When the transfer unit 14 transfers the toner image to the recording paper 4, the surface of the photoreceptor 10 is coated with the lubricant 20 that enhances the releasability of the toner, so that the toner image on the photoreceptor is efficiently transferred. Toner remaining on the photoreceptor 10 due to transfer is reduced. Developing unit 13
Makes toner adhere to the electrostatic latent image formed on the surface of the photoconductor 10 and efficiently removes residual toner adhering to the non-exposed area that has not been exposed from the surface of the photoconductor 10.

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 such as a printer, a facsimile machine and a copying machine, and more particularly to an improvement in the quality of an image formed by transferring a toner image formed on a photosensitive member to a transfer member. .

[0002]

2. Description of the Related Art In response to recent demands for space saving and cost reduction of an apparatus, a toner image formed on a photoreceptor is transferred by a transfer unit to a recording paper, which is a transfer target, in order to omit a cleaning unit. For example, Japanese Patent Application Laid-Open No. 8-137206 discloses a cleaning-less image forming apparatus in which the residual toner remaining without being transferred is moved with the rotation of the photoconductor as it is, and the residual toner is collected in the developing unit. Kaihei 8-185100
It is shown in Japanese Patent Publication No.

In the image forming apparatus disclosed in Japanese Patent Application Laid-Open No. 8-137206, the toner remaining on the surface of the photoreceptor after the transfer of the toner image by the transfer unit is charged by the charging unit or the exposure unit where the residual toner adheres. Alternatively, in order to suppress image defects such as afterimages caused by hindering exposure, the remaining toner is disturbed and dispersed using a charging rotating brush. The residual toner adhering to the non-exposed area is developed by a potential difference between the developing sleeve of the developing device in contact with the photoreceptor and the residual toner adhering to the non-exposed area of the photoreceptor not exposed by the exposure unit. And removed for recovery.

In the image forming apparatus disclosed in Japanese Patent Application Laid-Open No. 8-185100, in order to suppress image defects such as afterimages,
A roller-type brush charger and a toner dispersion capturing member are provided between the brush charger and the exposure unit. The brush charger scrapes off the residual toner on the photoreceptor surface and attaches it to the brush.Furthermore, the residual toner adhered to the brush is charged to the same polarity as the brush and flies over the photoreceptor by repulsion. Charges uniformly on the surface. The toner dispersion trapping member removes the residual toner on the surface of the photoconductor by dispersing the residual toner and attaching and holding the residual toner on a scraping brush. The photosensitive member is exposed by the exposure unit while the residual toner is held by the toner dispersion capturing member.

[0005]

However, when the amount of residual toner is too large to be recovered, for example, the surface of the photoconductor immediately below the residual toner is not charged in the charged portion, or the residual toner is not shadowed in the exposed portion. The light that falls on the part where the light is not sufficiently applied is lost. For this reason, the toner is attached to the portion where the residual toner is attached, or the image is whitened, and a so-called afterimage is generated. Further, there is a possibility that the residual toner that cannot be collected is fixed to the photoreceptor to cause filming, and conversely, the toner is fixed to the brush and charging performance is deteriorated.

In order to increase the transfer efficiency by reducing the amount of residual toner that cannot be recovered, for example, in an image forming apparatus disclosed in Japanese Patent Application Laid-Open No. 5-210300, a spherical toner is used as a developer. I have. However, spherical toner is disadvantageous in that the cost is very high because the toner is formed in a spherical shape, which directly leads to an increase in running cost.

Further, the image forming apparatus disclosed in Japanese Patent Application Laid-Open No. 6-342236 disposes a charging roller which rotates together with the photosensitive member during the transfer operation before the start of the transfer operation or after the end of the transfer operation. A lubricant that improves releasability from toner while rotating at a linear velocity different from the linear velocity is applied to the surface of the photoreceptor and collected by cleaning means to reduce the amount of toner remaining on the photoreceptor. I have to. However, the charging roller contacts the photoreceptor with a certain amount of pressure applied to apply the lubricant, and the linear velocity of the charging roller differs from the photoreceptor when applying the lubricant. In addition, friction occurs between the photoconductor and the charging roller, and the surfaces of the photoconductor and the charging roller are worn, thereby shortening the life of the photoconductor and the like. Further, the lubricant adheres to the charging roller due to friction between the photoreceptor and the charging roller, making it difficult to supply the lubricant to the photoreceptor or deteriorating the charging performance for the photoreceptor. There was a possibility.

SUMMARY OF THE INVENTION The present invention has been made in order to solve the above-mentioned disadvantage, and a cleaning-less image forming method capable of continuously forming a stable image for a long time by minimizing toner remaining on a photosensitive member. It is intended to obtain a device.

[0009]

SUMMARY OF THE INVENTION An image forming apparatus according to the present invention comprises a photosensitive member for holding a visible image, a charging brush roller for charging the surface of the photosensitive member which contacts while rotating, and a charged photosensitive member. An exposure unit that forms an electrostatic latent image by exposing, and a toner supply unit that supplies toner to the electrostatic latent image formed on the photoreceptor to form a toner image, and that the transfer unit transfers the toner image to a transfer target body In the image forming apparatus having a developing unit that recovers the toner remaining on the photoreceptor, a lubricant that enhances the releasability from the toner, and a supporting member that supports the lubricant at a position where the lubricant contacts the charging brush roller, The charging brush roller charges the photoreceptor surface and applies the scraped lubricant to the photoreceptor.

[0010] The support member may include a comb-shaped blade that contacts the charging brush roller. Further, the support member is desirably made of an insulating member.

Further, it is preferable to provide a movable portion for pushing out the support member so that the lubricant supported by the support member always comes into contact with the charging brush roller.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In an image forming apparatus according to the present invention, an image is printed and output on a recording sheet in accordance with image data generated by, for example, a host device or a scanner. And The image forming unit includes a photoconductor holding a visible image, a charging brush roller arranged around the photoconductor along a rotation direction, an exposure unit, a developing unit, and a transfer unit. The lubricant supply section includes a lubricant for improving the releasability from the toner, and a support member for supporting the lubricant at a position where the lubricant contacts the charging brush roller.

When image data is generated by a host device or a scanner, the charging brush roller charges the surface of the photoreceptor and applies the scraped lubricant between the fibers of the brush to the photoreceptor. In addition, dust such as toner or excessive lubricant clogged between the fibers of the brush is knocked down by an impact when the lubricant contacts the lubricant supported by the support member. The exposure unit forms an electrostatic latent image on the surface of the photoconductor coated with the lubricant,
The developing unit forms a toner image by attaching toner to the electrostatic latent image. Then, the transfer unit transfers the toner image on the surface of the photoreceptor to the recording paper sent in time. When the toner image is transferred to the recording paper, a lubricant that enhances the releasability of the toner is applied to the surface of the photoconductor, so that the toner image on the photoconductor can be transferred efficiently. Toner remaining on the photoreceptor can be reduced. After the transfer step, the toner remaining on the photoconductor moves to the contact surface with the charging brush roller by the rotation of the photoconductor.
The charging brush roller charges the photoreceptor surface to which the residual toner has adhered and applies a lubricant. The exposure unit forms an electrostatic latent image by performing exposure in a state where the residual toner adheres to the surface of the photoconductor. The developing unit attaches toner to the electrostatic latent image formed on the surface of the photoreceptor by the exposure unit, and removes residual toner adhering to the non-exposed area not exposed by the exposure unit from the surface of the photoreceptor. I do. When removing the residual toner adhered to the non-exposed area, the residual toner can be efficiently removed because the releasability from the photoconductor is enhanced by the lubricant.

As described above, the lubricant is applied to the photoreceptor using the charging brush roller to enhance the releasability between the photoreceptor and the toner, so that the transfer efficiency of the toner image by the transfer unit and the residual toner by the developing unit are improved. To reduce toner remaining on the photoreceptor as much as possible, thereby preventing image defects such as residual images caused by a large amount of toner remaining on the photoreceptor surface and improving image quality. be able to. In addition, the charged brush roller holds the scraped lubricant between the brush fibers and applies it to the photoreceptor to prevent pressure from being applied to the lubricant, and when the lubricant contacts the lubricant supported by the support member. The impact of rubbing off dust such as toner and excess lubricant clogged between the brush fibers prevents the charging performance from deteriorating due to sticking of lubricant etc. to the charging brush roller, and reduces the length of the charging brush roller. Life can be extended.

Further, by providing the supporting member with a comb-shaped blade which comes into contact with the charging brush roller, dust such as residual toner and excessive lubricant held between the fibers of the brush of the charging brush roller can be efficiently removed. Can be removed.

Further, a supporting member for supporting the lubricant at a position where the lubricant contacts the charging brush roller is formed of an insulating member, so that a bias voltage applied to the charging brush roller is applied to the housing via the supporting member supporting the lubricant. In order to prevent the lubricant from dropping onto the body, it is not necessary to provide a mechanism for bringing and removing the lubricant from the charging brush roller, and the cost of the apparatus can be reduced.

Further, by providing a movable portion for pushing out the support member so that the lubricant supported by the support member always comes into contact with the charging brush roller, the charging brush roller can always apply an appropriate amount of lubricant to the photosensitive member. In addition, uneven application of the lubricant to the photoconductor can be prevented. Further, the lubricant can be used for a long period of time without performing maintenance such as changing the position of the lubricant according to the consumption amount of the lubricant.

[0018]

FIG. 1 is a block diagram showing the configuration of an embodiment of the present invention. As shown in the figure, the image forming apparatus prints and outputs an image on a recording sheet in accordance with image data generated by a host device or a scanner, and has an image forming unit 1 and a lubricant supply unit 2. The image forming unit 1 includes a photoconductor 10 that holds a visible image, a charging brush roller 11 disposed along a rotation direction R of the photoconductor 10, and an exposure unit 1.
2 and a developing unit 13 and a transfer unit 14. The charging brush roller 11 comes into contact with the surface of the photoconductor 10,
The photoconductor 10 rotates at a different speed from the rotation speed. Then, a DC bias voltage or a bias voltage in which an AC component is superimposed on DC is applied from a bias power supply (not shown) to uniformly charge the surface of the photoconductor 10. As a brush material of the charging brush roller 11, a conductive fiber that can provide electric resistance, flexibility, strength, and the like in consideration of charging ability, surface hardness, rotation speed, and the like of the photoconductor 10 and the like is used. For example, a fiber or a resistance adjusting agent in which a resistance adjusting agent such as carbon black, carbon fiber, metal powder, metal whisker, or metal oxide is dispersed in a fiber formed of rayon, nylon, acrylic, polyester, polyethylene, or the like is dispersed. Fibers obtained by mixing fibers formed by mixing with ordinary fibers, spun fibers, or a fiber whose surface is coated with a resistance modifier material are used.

The exposure unit 12 is a charging brush roller 11
Exposes the surface of the photoconductor 10 charged to a predetermined potential to form an electrostatic latent image. The developing unit 13 includes the photoconductor 10
The toner is attached to the electrostatic latent image formed on the surface to visualize the image. The transfer unit 14 transfers the toner image formed on the surface of the photoreceptor 10 to the recording paper 4 fed by the separation roller 15 and fed at the timing by the registration roller 16. The recording paper 4 onto which the visible image has been transferred is separated from the photoreceptor 10 by a separation unit 17, subjected to a fixing process by a fixing unit 18, and discharged.

The lubricant supply section 2 has a lubricant 20 for improving the releasability from the toner, and a support member 21 formed of an insulating member for supporting the lubricant 20 at a position where the lubricant 20 contacts the charging brush roller 11. As the lubricant 20, a dry solid lubricant is used. Examples of the solid lubricant include zinc stearate, barium stearate, lead stearate, iron stearate, nickel stearate, cobalt stearate, copper stearate, strontium stearate, calcium stearate, cadmium stearate, and magnesium stearate. , Zinc oleate, manganese oleate, iron oleate, cobalt oleate,
Lead oleate, magnesium oleate, copper oleate, zinc palmitate, cobalt palmitate, copper palmitate, magnesium palmitate, aluminum palmitate, calcium palmitate, zinc caprylate, zinc linolenate, cobalt linolenate, linolenic acid Metal salts of fatty acids such as calcium, zinc licolinonenoate or cadmium licolinonenoate or colloidal high-temperature silica powder can be mentioned. The lubricant 20 is obtained by heating and melting this solid lubricant, for example, zinc stearate, and pouring it into a mold to form a bar shape.

An image forming operation in the image forming apparatus configured as described above will be described.

For example, when image data is generated by a host device, a scanner, or the like, the photoconductor 10 starts rotating clockwise R. On the other hand, the charging brush roller 11 charges the surface of the photoconductor 10 and applies the scraped lubricant 20 to the photoconductor 10. At this time, the charging brush roller 11 is
By rotating at a speed different from the rotation speed of 0, it is possible to suppress streak-like uneven charging of the photoconductor 10 unique to the brush. Further, the charging brush roller 11 holds the lubricant 20 scraped by the rotation between the fibers of the brush,
Since the lubricant 20 is conveyed to the contact surface with the surface of the photoreceptor 10 without applying pressure, the lubricant 20 is prevented from sticking to the brush fibers. In addition, the charging brush roller 11 strikes off dust such as toner or excessive lubricant clogged between the fibers of the brush by an impact when the charging brush roller 11 comes into contact with the lubricant 20 supported by the support member 21. Then, the exposure unit 12 forms an electrostatic latent image by exposing the surface of the photoreceptor 10 charged to a predetermined potential by the charging brush roller 11 and coated with the lubricant 20. The developing unit 13 forms a toner image by attaching toner to the electrostatic latent image formed on the surface of the photoconductor 10. At this time, the toner is applied to the lubricant 2 applied on the surface of the photoconductor 10.
Attach to 0. Then, the transfer unit 14 controls the recording paper 4 sent from the registration roller 16 at the same time.
The toner image on the photoconductor 10 is transferred to the photoconductor. When the toner image is transferred onto the recording paper 4, the toner image is transferred onto the surface of the photoconductor 10.
Since the lubricant 20 for improving the releasability of the toner is applied, the toner image on the photoconductor 10 can be transferred efficiently.
Toner remaining on the photoreceptor 10 can be reduced.

After the transfer step, the toner remaining on the photoreceptor 10 moves to the contact surface with the charging brush roller 11 by the rotation of the photoreceptor 10. The charging brush roller 11 charges the surface of the photoconductor 10 to which the residual toner has adhered, and applies the scraped lubricant 20. The exposure unit 12 includes the photoconductor 1
An electrostatic latent image is formed by exposing with the residual toner adhered to the surface 0. At this time, on the surface of the photoconductor 10, there are residual toner adhering on the electrostatic latent image, which is an exposure area, and residual toner adhering on a non-exposure area. Then, the developing unit 13 attaches the toner to the exposed area formed on the surface of the photoreceptor 10, forms a toner image together with the residual toner already attached, and absorbs the residual toner attached to the non-exposed area by, for example, adsorbing the toner. To remove from the surface of the photoconductor 10. When removing the residual toner attached to the non-exposure area, the residual toner can be efficiently removed because the releasability from the photoconductor 10 is enhanced by the lubricant.

As described above, the lubricant 20 is applied to the photoreceptor 10 by using the charging brush roller 11 to enhance the releasability of the photoreceptor 10 from the toner, so that the transfer efficiency of the toner image by the transfer unit 14 is improved. Since the toner remaining on the photoconductor 10 is reduced as much as possible by improving the efficiency of removing the residual toner by the developing unit 13, image defects such as afterimages caused by a large amount of toner remaining on the surface of the photoconductor 10 are eliminated. This can improve the image quality. The charging brush roller 11 holds the scraped lubricant 20 between the brush fibers and conveys the scraped lubricant 20 to the surface of the photoreceptor 10 to prevent pressure from being applied to the lubricant 20. The impact when contacting the lubricant 20 is used to knock down dust such as toner or excessive lubricant clogged between the fibers of the brush, so that the charging performance due to the lubricant 20 or the like being fixed to the charging brush roller 11 is reduced. Deterioration can be prevented, and the life of the charging brush roller 11 can be extended.

The lubricant 20 is supplied to the charging brush roller 11.
By forming the supporting member 21 that supports the position in contact with the roller with an insulating member, the bias voltage applied to the charging brush roller 11 is prevented from dropping into the housing via the supporting member 21 supporting the lubricant 20. Therefore, there is no need to provide a mechanism for contacting / separating the lubricant 20 from / to the charging brush roller 11 or to perform complicated control for separating the process of charging the photosensitive member 10 and applying the lubricant, thereby reducing the cost of the apparatus. Can be.

The charging brush roller 11 strikes off dust such as toner or excess lubricant clogged between the fibers of the brush by an impact when the charging brush roller 11 comes into contact with the lubricant 20 supported by the support member 21. As shown in FIG.
When the charging brush roller 11 is provided with a comb-shaped blade 22 that contacts the charging brush roller 11, the charging brush roller 11
2, the comb-shaped irregularities of the blade 22 enter between the brushes, so that dust such as residual toner and excessive lubricant 20 clogged between the fibers of the brushes can be efficiently removed. .

As described above, the comb-shaped blade 22 which contacts the charging brush roller 11 is provided on the supporting member 21, and the residual toner clogged between the brush fibers of the charging brush roller 11 by the blade 22, the excessive lubricant 20, etc. To efficiently remove dust from the charging brush roller 1
1 reliably prevents the deterioration of the charging performance of the charging brush roller 1
1, the service life can be extended.

The support member 21 of the lubricant supply unit 2
Supports the lubricant 20 at a position where the lubricant 20 is in contact with the charging brush roller 11. However, the supporting member 21 supports the lubricant 20 supported by the supporting member 21 so that the lubricant 20 always contacts the charging brush roller 11.
May be provided. For example, as shown in FIG. 3, the lubricant supply unit 2 includes a lubricant 20 and a support member 2.
1, a blade 22 and a movable part 3. Support member 2
1 is held by a housing so as to be movable about a shaft provided at both ends, and a shaft at one end is provided with a contraction spring 23 for regulating the position. The movable portion 3 includes, for example, a shaft 30 rotatably attached to a housing, arms 31 and 32 fixed to the shaft 30 so as to abut on the back surface of the support member 21, and an eccentric cam 33 for moving the arms 31 and 32. A motor 34 for rotationally driving the eccentric cam 33;
For example, a control unit (not shown) that controls the rotation of the motor 34 according to information from a sensor that detects the number of image forming processes or the amount of consumption of the lubricant 20. Then, FIG.
As shown in (2), for example, before the supply amount of the lubricant 20 to the photoreceptor 10 decreases due to the increase in the distance from the surface of the lubricant 20 to the charging brush roller 11 due to the consumption of the lubricant 20, Number of image forming processes or lubricant 20
According to the information from the sensor that detects the consumption of
The eccentric cam 33 is rotated via the motor 34 as shown in FIG. Arms 31 and 32 are rotated eccentric cams 33
By pressing the support member 21 on the shaft 30, the support member 21 is pushed toward the charging brush roller 11 by pushing the back surface of the support member 21. The support member 21 includes arms 31 and 3
The lubricant 20 supported by being extruded by the second brush 2 is brought into contact with the charging brush roller 11.

As described above, the movable portion 3 for pushing the supporting member 21 so that the lubricant 20 supported by the supporting member 21 always contacts the charging brush roller 11 is provided, and a proper amount of the lubricant 20 is always exposed by the charging brush roller 11. Since the lubricant 20 is applied to the body 10, the lubricant 20
Can be prevented from being applied unevenly, and the image quality can be improved. Further, the lubricant 20 can be used for a long period of time without performing maintenance such as changing the position of the lubricant 20 according to the consumption amount of the lubricant 20.

In the above-described embodiment, the case of forming an image of only a single color has been described. However, for example, a plurality of image forming units for forming a visible image of each color are arranged along a recording paper conveyance path. The visible image of each color formed on each photoreceptor is sequentially transferred to recording paper to form a color image, or a single photoreceptor is provided with a developing unit for each color, and the visible image of each color formed sequentially is formed. The present invention may be applied to an image forming apparatus in which a color image is formed by superimposing and holding an intermediate transfer member, and transferring a visible image of each color superimposed and held on recording paper.

[0031]

As described above, according to the present invention, the transfer efficiency of the toner image by the transfer unit is improved by applying the lubricant to the photoreceptor using the charging brush roller to enhance the releasability between the photoreceptor and the toner. In addition, since the toner remaining on the photoconductor is reduced as much as possible by improving the efficiency of removing the residual toner by the developing unit, image defects such as afterimages caused by a large amount of toner remaining on the photoconductor surface are prevented. ,
Image quality can be improved. In addition, the charging brush roller holds the scraped lubricant between the fibers of the brush and conveys the lubricant to the surface of the photoreceptor, thereby preventing pressure from being applied to the lubricant and contacting the lubricant supported by the support member. In this case, dust such as toner and excessive lubricant clogged between the fibers of the brush is knocked down by the impact of the brush, so that the charging performance is prevented from deteriorating due to the adhesion of the lubricant or the like to the charging brush roller, and the charging brush roller The service life can be extended.

Further, a comb-shaped blade is provided on the supporting member so as to be in contact with the charging brush roller, and the blade efficiently removes dust such as residual toner and excessive lubricant clogged between the brush fibers of the charging brush roller. As a result, the charging performance of the charging brush roller is reliably prevented from deteriorating.
The life of the charging brush roller can be extended.

Further, a supporting member for supporting the lubricant at a position in contact with the charging brush roller is formed of an insulating member, so that a bias voltage applied to the charging brush roller is applied to the housing via the supporting member supporting the lubricant. This eliminates the need to provide a lubricant contact / separation mechanism for the charging brush roller, and to perform complicated control for separating the charging of the photoconductor and the application of the lubricant. Reduction can be achieved.

Also, a movable portion is provided for pushing out the support member so that the lubricant supported by the support member always comes into contact with the charging brush roller, and an appropriate amount of the lubricant is always applied to the photoreceptor by the charging brush roller. It is possible to prevent uneven application of the lubricant to the photoreceptor and to improve image quality. Further, the lubricant can be used for a long period of time without performing maintenance such as changing the position of the lubricant according to the consumption amount of the lubricant.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing a configuration of an embodiment of the present invention.

FIG. 2 is a perspective view of a lubricant supply unit provided with a blade.

FIG. 3 is a perspective view of a lubricant supply unit provided with a movable unit.

FIG. 4 is a side view showing the operation of the movable unit.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Image forming part 11 Charging brush roller 12 Exposure unit 13 Developing unit 14 Transfer unit 2 Lubricant supply part 20 Lubricant 21 Support member

Claims (4)

[Claims] 1. A photoreceptor for holding a visible image, a charging brush roller for charging a surface of the photoreceptor contacted while rotating,
An exposure unit that forms an electrostatic latent image by exposing a charged photoconductor, and a toner image is formed by supplying toner to the electrostatic latent image formed on the photoconductor, and the transfer unit receives the toner image. An image forming apparatus having a developing unit for recovering toner remaining on the photoconductor by transferring the toner to a body, a lubricant for improving releasability from the toner, and a support for supporting the lubricant at a position where the lubricant contacts the charging brush roller An image forming apparatus having a member, wherein a charging brush roller charges the surface of the photoconductor and applies a scraped lubricant to the photoconductor. 2. The image forming apparatus according to claim 1, wherein the support member includes a comb-shaped blade that contacts the charging brush roller. 3. The image forming apparatus according to claim 1, wherein said support member is made of an insulating member. 4. The image forming apparatus according to claim 1, further comprising a movable portion that pushes out the support member so that the lubricant supported by the support member always contacts the charging brush roller.