JPH10260614A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To uniformly apply lubricant on a photoreceptor surface, also, to reduce the biting quantity of a brush, to reduce the rotating speed of a lubricant applying member and to prolong the life of the lubricant applying member by setting the bristle density of the brush of the lubricant applying member at a specified value or higher. SOLUTION: The lubricant applying member 60 is installed in the cleaning case 20 of a cleaning device 70, and the base end part of a sheet-like lubricant holding member 64 is rotatably and pivotally supported through a pin 63 in the cleaning case 20, solid lubricant 65 is held by the leading end part of the lubricant holding member 64, the lubricant holding member 64 is energized clockwise by an energizing member constituted of a pressure spring, then, the solid lubricant 65 is brought into press contact with the brush 62. In this case, it is important to increase the bristle density of the brush 62 of the lubricant applying member 60 in order to suppress unevenness in applying the lubricant on the photoreceptor surface, then, the bristle density of the brush 62 of the lubricant applying member 60 is set >=20,000 pieces/645.16mm<2> in this case.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image carrier on which a toner image is formed on the surface while being rotated, a transfer device for transferring the toner image to a transfer material, and a surface of the image carrier after the toner image is transferred. A cleaning member for cleaning the surface of the image carrier by removing transfer residual toner adhering to the surface of the image carrier, and a lubricant for applying a lubricant to the surface of the image carrier while being rotationally driven while having a brush contacting the surface of the image carrier The present invention relates to an image forming apparatus including an application member.

[0002]

2. Description of the Related Art Electronic copiers, printers, facsimile machines,
Alternatively, an image forming apparatus of the above type configured as a multifunction peripheral having at least two of these functions has been conventionally known (see Japanese Patent Application Laid-Open No. 56-154778).
According to this type of image forming apparatus, since the lubricant is applied to the surface of the image carrier, the coefficient of friction of the surface of the image carrier with respect to the toner can be reduced, whereby the toner formed on the surface of the image carrier can be reduced. It is possible to suppress the occurrence of transfer failure when transferring the image to the transfer material, and to improve the quality of the transferred toner image. In particular, it is possible to suppress the occurrence of a character portion hollowing phenomenon in which a part of a character image is missing like a bug, and to improve the image quality.

However, when a lubricant is applied to the surface of the image carrier, the friction coefficient of the surface with respect to the toner is reduced. Therefore, if the amount of the lubricant applied to the surface of the image carrier becomes non-uniform, the unevenness of the application causes The amount of toner adhered to the toner image formed on the surface of the image carrier becomes non-uniform, and uneven density occurs in the toner image to degrade the image quality. A small amount of toner adheres to the surface of the image carrier where the amount of lubricant applied is large, and a large amount of toner adheres to a portion where the amount of lubricant is small, resulting in uneven density in the toner image. You do it. In particular, density unevenness tends to occur in a low-density toner image.

In view of the above, various configurations have conventionally been proposed for making the amount of the lubricant applied to the surface of the image bearing member uniform. However, any of these countermeasures complicates the configuration of the image forming apparatus or increases the complexity. This was accompanied by the disadvantage of increasing costs.

[0005]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a simple and inexpensive arrangement which can increase the uniformity of the amount of lubricant applied to the surface of an image bearing member. An object of the present invention is to provide an image forming apparatus.

[0006]

According to the present invention, in order to achieve the above object, in an image forming apparatus of the type described at the beginning, the density of brushes of a lubricant application member is 20,000 / 64.
An image forming apparatus characterized by being at least 5.16 mm ² is proposed (claim 1).

In this case, in the image forming apparatus according to the first aspect of the present invention, the rotational speed of the lubricant applying member is R, the amount of penetration of the brush of the lubricant applying member into the surface of the image carrier is δ, and the brush is in contact with the lubricant. When the pressure at which the solid lubricant to be brought into contact with the brush is P, 55 rpm ≦ R ≦ 220 rpm, 0 mm <δ
It is advantageous to satisfy ≦ 1 mm and 0 mN <P ≦ 400 mN, respectively (claim 2).

The image forming apparatus according to claim 1 or 2, wherein the rotation direction of the image carrier is downstream of a transfer unit that transfers a toner image to a transfer material by the transfer device. A lubricant holding member for holding a solid lubricant with which the brush of the lubricant applying member comes into contact with the surface of the image carrier upstream of the cleaning section for cleaning the surface of the image carrier by the cleaning member. Advantageously, an opening through which the residual toner scraped off from the surface of the image carrier by the brush of the lubricant applying member passes through the lubricant retaining member is formed in the lubricant retaining member. 3).

Further, in the image forming apparatus according to any one of claims 1 to 3, the rotation direction of the image carrier is downstream of a transfer unit that transfers a toner image to a transfer material by the transfer device. A lubrication device that contacts a brush of the lubricant applying member with an image carrier surface upstream of a cleaning unit that cleans the image carrier surface with the cleaning member, and holds a solid lubricant with which the brush contacts. It is advantageous to provide a brush holding member which has an agent holding member and which comes into contact with the brush of the lubricant applying member (claim 4).

In the image forming apparatus according to the present invention, in the rotational direction of the lubricant applying member, the brush of the lubricant applying member is downstream of a portion where the brush contacts the surface of the image carrier, and It is advantageous that the brush contact member abuts on a brush portion upstream of a portion where the brush contacts the solid lubricant (claim 5).

Furthermore, in the image forming apparatus according to claim 4 or 5, the brush contact member is formed integrally with the lubricant holding member, and the brush contact member is scraped off from the surface of the image carrier by the brush of the lubricant application member. It is advantageous to form an opening in the brush contact member through which the remaining transfer toner passes (claim 6).

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a schematic diagram showing the internal structure of a color image forming apparatus configured as a printer. The main body 1 of the image forming apparatus shown here includes a fixed main body 2 that is immovably mounted on an installation surface such as a floor surface, and a rotating main body 3 that is rotatably supported by the fixed main body 2. , This rotating body 3
Further, a process unit 4 in which a plurality of process elements are integrally assembled is detachably mounted. FIG. 2 is a sectional view showing the inside of the process unit 4.

In FIGS. 1 and 2, an endless belt-shaped photosensitive member 8 constituting an example of an image carrier is wound around rollers 6 and 7 rotatably supported by a unit case 5 of a process unit 4. ing. As the image carrier, a drum-shaped photoconductor, a dielectric drum or a dielectric belt can be used. A charging device including a charging charger 9 is disposed at a position facing the photoconductor 8, and the charging charger 9 is also supported by the unit case 5.

On the other hand, the fixed body 2 supports an exposure device configured as a laser writing unit 10, a rotary type color developing unit 11, and a black developing unit 12, respectively. The device is configured. Laser writing unit 1
Reference numeral 0 denotes a laser light source (not shown) and an optical system for scanning light from the light source onto the surface of the photoconductor.

The color developing unit 11 includes a yellow developing unit 11Y, a magenta developing unit 11M, and a cyan developing unit 11M.
C is integrally assembled, and the whole is rotatably supported by the fixed main body 2. The yellow developing unit 11Y, the magenta developing unit 11M, the cyan developing unit 11C, and the black developing unit 12 contain yellow, magenta, cyan, and black developers, respectively. As the developer, either a two-component developer having a toner and a carrier or a one-component developer having no carrier may be used. Further, a liquid developer can be used, but in the illustrated example, a powdery developer is used.

During the image forming operation, the photosensitive member 8 is rotationally driven in the direction of arrow A by driving the roller 7 by a driving device (not shown). At this time, the surface of the photosensitive member is subjected to a charge removing operation by a charge removing lamp 13 which is an example of a charge removing device, and then the surface of the photosensitive member is uniformly charged by a charging device including a charging charger 9.
Exposure is performed by the light-modulated laser light L emitted from the laser writing unit 10, whereby a first electrostatic latent image is formed on the surface of the photoconductor. At this time, for example, the yellow developing unit 11Y of the color developing unit 11 is located to face the surface of the photoconductor 8, and the yellow developing unit 11Y
Thus, the first electrostatic latent image is visualized as a yellow toner image. At this time, the black developing unit 12
Is separated from the surface of the photoreceptor 8 and does not perform the developing operation.

On the other hand, the unit case 5 has an appropriate number of rollers 14, 1 (in this example,
5 is rotatably supported, and an endless intermediate transfer belt 16 which is an example of an intermediate transfer member is attached to these rollers 14 and 15.
Is wound, and one of the rollers 14 is driven by a driving device (not shown), so that the intermediate transfer belt 16 is rotationally driven in the direction of arrow B. The intermediate transfer belt 16 and the photoconductor 8 abut on each other at a transfer portion 17, and the front end of a transfer brush 18, which is an example of a transfer device, abuts on the back surface of the intermediate transfer belt 16 at this portion.
The transfer brush 18 is also supported by the unit case 5. As the transfer device, a transfer roller, a corona discharger, or the like can be used.

When the yellow toner image formed on the surface of the photosensitive member 8 reaches the transfer portion 17 as described above, a voltage having a polarity opposite to that of the toner is applied to the transfer brush 18, whereby the photosensitive member 8 is moved. The toner image on the surface is the intermediate transfer belt 1
6 is transferred to the surface. Thus, the intermediate transfer belt 1
Reference numeral 6 denotes an example of a transfer material to which the toner image formed on the surface of the photoconductor is transferred.

After the transfer of the toner image,
Toner remaining without being transferred is attached, and the transferred toner is scraped off by a cleaning member composed of a cleaning blade 19 supported by the unit case 5 and having a front end pressed against the photoconductor 8. . The transfer residual toner removed from the photoreceptor surface in this way is
It falls into the cleaning case 20 integrated with the unit case 5. As a cleaning member, other appropriate means such as a fur brush can be adopted,
Also, a plurality of cleaning members can be used in combination.
Cleaning blade 19 and cleaning case 20
The cleaning device 70 for the photoconductor 8 is constituted by the toner conveying screw 38 described below.

The surface of the photoreceptor whose surface has been cleaned as described above is again subjected to a discharging operation by the discharging lamp 13,
The charged surface is uniformly charged by the charging charger 9, and then the charged surface is irradiated with the laser light L emitted from the laser writing unit 10 to form a second electrostatic latent image on the surface of the photoconductor. When this electrostatic latent image passes through the color developing unit 11, the rotation of the unit 11 causes, for example, a magenta developing unit 11M to face the photoconductor 8, whereby the second electrostatic latent image becomes a magenta toner image. As a visible image. This toner image is also transferred to the surface of the intermediate transfer belt 16 on which the yellow toner image has been previously transferred by being superimposed on the yellow toner image by the operation of the transfer brush 18 in exactly the same manner as described above. . The toner remaining on the surface of the photoconductor 8 after the transfer of the magenta toner image is also removed from the photoconductor surface by the cleaning blade 19.

In exactly the same manner as described above, a cyan toner image and a black toner image are sequentially formed on the photoreceptor surface by a cyan developing unit 11C and a black developing unit 12 facing the photoreceptor surface, respectively. On the surface of the intermediate transfer belt 16, the toner image is sequentially transferred while being superimposed on the previously transferred toner image. The transfer blade removes the transfer residual toner from the photoreceptor surface every time each toner image is transferred, and the surface is cleaned. Thus, a full-color toner image is formed on the surface of the intermediate transfer belt 16. At the time of forming a black toner image, the black developing unit 12 is brought close to the surface of the photoconductor 8, and performs a predetermined developing operation.

On the other hand, a recording medium 22 made of paper or a plastic sheet is stacked on a sheet cassette 21 set in the fixed main body 2, and the recording medium 22 is moved one by one by rotation of a sheet feeding roller 23. The paper is fed in the C direction. The recording medium 22 fed in this manner is conveyed by a pair of conveying rollers 24 and a pair of registration rollers 25 rotatably supported by the rotating main body 3, and a full-color toner image formed on the surface of the intermediate transfer belt 16. Is fed into a nip portion between the intermediate transfer belt 16 and a transfer roller 26 which is an example of a transfer device opposed to the intermediate transfer belt 16 at a timing matching with the transfer roller. At this time, a voltage having a polarity opposite to that of the toner applied to the transfer roller 26 is applied to the intermediate transfer belt 1.
The full-color toner images on the six surfaces are transferred to the surface of the recording medium 22. Transfer roller 26 constituting an example of a transfer device
Is rotatably supported by the rotating main body 3, and as such a transfer device, an appropriate means such as a corona discharger or a brush can be adopted.

After leaving the intermediate transfer belt 16, the recording medium 22 onto which the full-color toner image has been transferred passes between a fixing roller 28 and a pressure roller 29 of a fixing device 27 provided on the fixed main body 2. Sometimes by the action of heat and pressure,
The toner image is fixed on the surface of the recording medium 22. The recording medium 22 that has exited from the fixing device 27 is discharged with the image surface downward to a discharge stack portion 31 above the fixed main body by a pair of discharge rollers 30 rotatably supported by the fixed main body 2.

On the other hand, the full-color toner image is
The transfer residual toner remaining on the intermediate transfer belt 16 after being transferred to the intermediate transfer belt 16 is scraped off by a cleaning blade 32 having a front end pressed against the surface of the intermediate transfer belt 16, and the surface of the intermediate transfer belt 16 is cleaned. The cleaning blade 32 constitutes an example of a cleaning member for the intermediate transfer belt 16. The cleaning blade 32 is fixed to an arm 33 swingably supported by the unit case 5, and the intermediate transfer is performed by the cleaning blade 32. The transfer residual toner scraped from the belt 16 is received by a toner receiver 34 fixed to the arm 33. As this cleaning member, a cleaning member of another appropriate form such as a fur brush can be adopted.

The cleaning blade 32 includes an arm 33
The cleaning blade 32 is separated from the surface of the intermediate transfer belt 16 when each toner image is transferred to the surface of the intermediate transfer belt 16 by the swing of. After transferring the full-color toner image on the surface of the intermediate transfer belt to the recording medium 22, only when cleaning the toner remaining on the surface, the tip of the cleaning blade 32 is pressed against the surface of the intermediate transfer belt by the swing of the arm 33, The transfer residual toner is scraped off.

The cleaning blade 32 extends in the width direction of the intermediate transfer belt 16, and the toner receiver 34 extends along the cleaning blade 32. The transfer residual toner scraped from the surface of the intermediate transfer belt by the cleaning blade 32 is
The toner is conveyed by the toner conveying screw 37 toward the near side with respect to the plane of FIG. Next, the toner is sent to the cleaning case 20 through the toner conveying duct 36 arranged on the front side of the unit case 5.

Also, the cleaning blade 19 which is in pressure contact with the surface of the photosensitive member 8 extends in the width direction of the photosensitive member 8, and the cleaning case 20 extends along this.
The transfer residual toner scraped off from the surface of the photoconductor 8 by the cleaning blade 19 and the transfer residual toner sent to the cleaning case 20 through the toner transport duct 36 are transferred by a toner transport screw 38 provided at the bottom of the cleaning case 20. After being conveyed, the toner drops from the toner discharge port 50 to the toner guide tube 51, and is then fed into the waste toner container 35 from the inlet 40 and stored therein.

The above description is about the image forming operation when forming a full-color image on the recording medium 22, but only one of the developing units constituting the color developing unit 11 and one of the black developing units 12 is used. To form a single-color image or a two-color or three-color image.

In the illustrated image forming apparatus, the rotating main body 3 forming a part of the main body 1 of the image forming apparatus has a rotating roller 15 around which the intermediate transfer belt 16 is wound around the fixed main body 2. It is pivotally supported about a central axis in the direction of arrow E in FIG. The state of a part of the rotating main body 3 when rotated in this way is shown by a chain line in FIG. When the rotating main body 3 is rotated to the open position in this manner, the upper portion of the waste toner container 35 is opened. When the waste toner in the waste toner container 35 becomes full, the container 35 is removed. And the waste toner container 35 can be replaced. Also, when the deterioration of the photoconductor 8 is advanced and the photoconductor 8 reaches the end of its life, the rotating main body 3 is rotated to the open position indicated by the chain line in FIG. 1 to replace the entire process unit 4 with a new one. be able to.

An electric control unit 41 is provided on the left side in FIG. 1, and a fan 42 is disposed above the electric control unit 41. The fan 42 exhausts air from the inside of the machine to prevent an excessive rise in temperature inside the machine. it can. In addition, a relatively small-sized paper feeding device 43 is provided in the right portion of FIG.

As described above, the image forming apparatus according to the present embodiment has the photosensitive member 8 on which a toner image is formed on the surface while being rotated.
, A transfer device configured as a transfer brush 18 for transferring the toner image to a transfer material including an intermediate transfer belt 16, and transfer residual toner adhered to the surface of the image carrier after the transfer of the toner image And a cleaning member configured as a cleaning blade 19 for removing the image carrier and cleaning the surface of the image carrier.

Here, the transfer failure at the time of transferring the toner image formed on the surface of the photoconductor 8 as an example of an image carrier to the surface of the intermediate transfer belt 16 as an example of a transfer material is suppressed, and the image forming apparatus is completed. In order to prevent the occurrence of missing characters in an image, the illustrated image forming apparatus is provided with a lubricant application member 60 as shown in FIG.

The lubricant application member 60 shown as an example in FIG.
Has a central shaft 61 that extends long in the width direction of the photoconductor 8, that is, the axial direction thereof, and a brush 62 made of a number of hairs provided on the outer peripheral surface thereof. For example, a brush 62 is implanted on a base cloth (not shown), and the base cloth is
The lubricant application member 60 is configured by fixing the lubricant application member to the outer peripheral surface. The tip of the brush 62 contacts the surface of the photoconductor 8 over substantially the entire width thereof. Also, the rotating shaft 61
Extend in a direction perpendicular to the paper surface of FIGS. 1 to 3 at a fixed interval from the photoreceptor surface, and are rotatably supported by front and rear side walls of a cleaning case 20 which constitutes an example of a supporting member thereof; It is rotationally driven in an appropriate direction by a driving device (not shown), for example, clockwise (direction of arrow D) in the example of the figure. At the contact portion between the brush 62 and the surface of the image carrier made of the photoreceptor 8, the rotation direction of the lubricant application member 60 is set so that the two move in opposite directions.

As described above, the lubricant application member 60 of the present embodiment is used.
Is provided inside the cleaning case 20 of the cleaning device 70, and a base end of a plate-shaped lubricant holding member 64 is pivotally attached to the cleaning case 20 via a pin 63, A solid lubricant 65 is held at the tip of the lubricant holding member 64, and the lubricant holding member 64 is pressed by an urging member (not shown) including a pressure spring.
Are urged clockwise in FIG. 3, whereby the solid lubricant 65 is pressed against the brush 62. Lubricant holding member 6
4, an opening 66 is formed as shown in FIG. 4, which will be described later in detail.

Lubricant application member 60 rotating in the direction of arrow D
The brush 62 contacts the solid lubricant 65,
The lubricant is scraped little by little from the solid lubricant 65. The lubricant transferred to the brush 62 in this manner is applied to the brush 6
2 is applied to the surface of the photoreceptor 8 driven in the direction of arrow A while contacting the surface 2. As a result, the coefficient of friction of the surface of the photoconductor with respect to the toner is reduced, and the toner image formed on the surface of the photoconductor can be efficiently transferred to the surface of the intermediate transfer belt 16.
It is possible to effectively suppress the occurrence of the character missing phenomenon in the toner image on the surface of the intermediate transfer belt due to the transfer failure, and to improve the quality of the image transferred to the final recording medium 22.

As the solid lubricant 65, for example, a dry solid hydrophobic lubricant is used. Typical examples thereof include zinc stearate, barium stearate, lead stearate, iron stearate, nickel stearate, and stearic acid. Cobalt, copper stearate, strontium stearate, calcium stearate, cadmium stearate, magnesium stearate, zinc oleate, manganese oleate, iron oleate, cobalt oleate, lead oleate, magnesium oleate, copper oleate, partimine Acid, zinc zinc palmitate, copper palmitate, magnesium palmitate, aluminum palmitate, calcium palmitate, lead caprylate, lead caproate, zinc linolenate, cobalt linolenate, calcium linolenate Arm, and the like can be given a relatively higher fatty acid such as Rikorinoren cadmium. Natural waxes such as carnauba wax can also be used.

As described above, the image forming apparatus of this embodiment has the brush 62 that comes into contact with the surface of the image carrier composed of the photoreceptor 8, and applies the lubricant to the surface of the image carrier while being driven to rotate. A lubricant application member 60 is provided.

When the amount of the lubricant applied to the surface of the photoreceptor by the above-described lubricant applying member 60, that is, the amount of the applied lubricant becomes non-uniform, as described above,
Density unevenness occurs in the toner image formed on the photoreceptor surface. In particular, when the brush 62 is in contact with the surface of the photoconductor upstream of the cleaning blade 19 as in this embodiment, a part of the transfer residual toner attached to the surface of the photoconductor is also scraped off by the brush 62. At this time, a small amount of the lubricant is removed from the photoreceptor surface together with the toner. This is considered to be the same when the cleaning blade 19 scrapes the transfer residual toner from the photoconductor surface.

At this time, the transfer residual toner does not adhere to the surface of the photoreceptor in a uniform distribution, but a relatively large amount of the transfer residual toner adheres to the portion where the toner image before transfer is formed. The remaining toner is not substantially adhered to other portions. Also, depending on the image density of the toner image,
The amount of transfer residual toner is different. A large amount of lubricant is scraped off together with the toner by the brush 62 and the cleaning blade 19 from the place where the amount of the transfer residual toner is large, so that the amount of the lubricant applied to the photoreceptor surface is uneven. There is a possibility that.

The lubricant applied to the surface of the photoreceptor lowers the coefficient of friction of the surface. Therefore, if the amount of application is not uniform, the amount of toner of the toner image formed on the surface of the photoreceptor is also reduced. The amount becomes uneven according to the amount of unevenness, and the image density becomes uneven. Particularly, in the case of a low density image, the density unevenness is likely to occur.

The inventor of the present invention has studied various measures for suppressing the increase in the cost of the image forming apparatus and for uniformly applying the lubricant to the surface of the photoreceptor, by repeating many experiments.

As a result, it is important to increase the density of the bristles of the brush 62 of the lubricant applying member 60 in order to suppress the uneven application of the lubricant on the surface of the photoreceptor. It was also found that the lubricant can be uniformly applied to the surface of the photoreceptor even if the amount of the brush 62 that is inserted into the photoreceptor 8 is set to be extremely small. In particular, the density of the bristles is ² per square inch (645.16 mm ² ).
It has been found that when the number is set to 10,000 or more, the lubricant can be uniformly applied to the surface of the photoreceptor even if the number of rotations of the lubricant applying member and the amount of penetration of the brush are set extremely small.

In the image forming apparatus of this embodiment, the density of the bristles of the brush 62 of the lubricant applying member 60 is set to 20,000 / 645.16 mm ² or more based on such knowledge. In order to clarify that the above-described operation and effect can be achieved by this configuration, an experimental example conducted by the inventor will be introduced.

In all of the experiments, the image forming apparatus shown in FIGS. 1 to 4 was used, and only a black developing unit 12 was used as a developing device to form a black monochromatic image on a recording medium 22 made of paper. . At this time, the ratio of the image area to the area of the recording medium was 5%.

First, the density of the bristles of the brush 62 is 0.5, 1, ^2, 3.5 per square inch (645.16 mm ² ).
And 50,000 new lubricant application members 60 are prepared, each of which is sequentially assembled to the image forming apparatus as shown in FIGS. 1 to 4, and each of them is made of paper in a room at room temperature and room. 1000 toner images were formed on the recording medium 22 each time, and the image quality of the image on the recording medium 22 was evaluated every time the number of printed sheets reached 1, 100, 200, and 1000 sheets. Table 1 shows the results.

In Table 1, ○ indicates that the unevenness in the application of the lubricant to the photosensitive member 8 was extremely small, and no unevenness in the density was observed even in the low-density portion of the toner image on the obtained recording medium.
Δ indicates that some density unevenness was observed in the low density part, and X indicates that density unevenness was clearly apparent. This is the same in Tables 2 to 4 described later.

In the first experiment shown in Table 1, the rotational speed R of the lubricant application member 60 was 110 rpm, the amount of penetration δ of the brush 62 of the lubricant application member 60 into the surface of the photoreceptor was 1 mm, and the solid lubricant 65 was used. The pressure P contacting the brush 62 is 400 mN
(Millinewton), the linear velocity on the surface of the photoconductor 8 is 96 mm /
Seconds. The brush density in Table 1 indicates the density of the bristles of the brush, and the unit is 10,000 brushes / 645.16 mm ² . The pressure P at which the solid lubricant 65 abuts on the brush 62 depends on the weight of the solid lubricant 65 and the lubricant holding member 64 and the force of the above-described pressure spring that presses the solid lubricant 65 against the brush 62. This is the total value.

[0049]

[Table 1]

As can be seen from Table 1, the density of the bristles of the brush is 50,000 / 645.16 mm ² and 10,000 / 645.16 m.
At m ² , density unevenness appears in the image on the recording medium 22. On the other hand, the brush density was 20,000 brushes / 645.16.
If it is more than ² mm, the density unevenness of the image will sharply disappear,
The image quality is enhanced.

When the density of the bristles of the brush 62 is set to 20,000 / 645.16 mm ² or more as described above, the lubricant can be uniformly applied to the surface of the photoreceptor, and the unevenness of the image density can be prevented. The rotational speed R of the lubricant application member 60 is 110
The rpm and the biting amount δ of the brush are 1 mm, which are small values. The number of revolutions of the lubricant application member 60 is increased, and the brush 62 is pressed against the surface of the photoreceptor with a large pressure, and the tip of the brush abutting on the surface of the photoreceptor is largely bent and deformed by the reaction force from the surface of the photoreceptor. If the amount of penetration of the brush is increased, a large load is constantly applied to the brush 62 during operation of the image forming apparatus, and excessive stress is generated in the brush 62, and the brush 62 deteriorates early and its life is shortened. Is shrunk. When the density of the bristles of the brush is set to 20,000 / 645.16 mm ² or more, the lubricant can be uniformly applied to the surface of the photoreceptor, the amount of penetration of the brush can be reduced, and the rotation speed of the lubricant application member 60 can be reduced. Therefore, the life of the lubricant application member can be prolonged.

The brush 62 has a bristle density of 20,000 hairs / 6.
If it is 45.16 mm ² or more, the occurrence of image density unevenness can be suppressed, and the upper limit is not particularly defined. However, the density of the bristles of the brush 62 is 100,000 / 645.
If it exceeds 16 mm ² , the density will be too high, and the function as a brush will be reduced.
Producing brushes having a density of 5.16 mm ² or more is not easy with current production techniques. Therefore, if the density of the bristles of this brush is 20,000 / 645.16 mm ² or more, it is 100,000 // 6.
It is practically most preferable to set the diameter to 45.16 mm ² or less.

The amount of penetration of the brush 62 into the surface of the photoreceptor will now be described. First, as shown in FIG. 7, the brush 62 is set in a free state so as not to bend, and the tip of the brush is moved to the image carrier. In this example, the distance from the rotation center X of the lubricant applying member 60 to the surface of the image bearing member with which the tip of the brush 62 contacts when contacting the surface of the photosensitive member 8 is D.
_Set to ₁ . On the other hand, FIG. 8 shows that the lubricant application member 60 is actually incorporated in the image forming apparatus as shown in FIGS.
The state in which the tip of the brush 62 is pressed against the surface of the image carrier made of the photoconductor 8 and the tip of the brush is bent is shown from the rotation center X of the lubricant application member 60 at this time. brush tip the distance to the surface of the image bearing member which is pressed against a D _2. Then, δ represented by D ₁ −D ₂ becomes
This is the amount of engagement of the brush 62.

Next, Table 2 shows that the solid lubricant 65
2 shows the results of a second experiment when the pressure P abutting on was changed. The density of the brush hair at this time is 20,000 / 6
45.16 mm ² , the amount of penetration δ of the brush 62 into the surface of the photoreceptor is 1 mm, and the rotation speed of the lubricant applying member 60 is 110 rp.
m, the linear velocity on the surface of the photoreceptor is 96 mm / sec.

[0055]

[Table 2]

As can be seen from Table 2, the solid lubricant pressure P
Is 600 mN or more, density unevenness appears in the image on the recording medium 22. Therefore, the pressing force P is preferably 400 mN or less and more preferably 0 mN. As described above, when the density of the bristles of the brush is set to 20,000 / 645.16 mm ² or more, it is more likely that the pressure P at which the solid lubricant 65 is in contact with the brush 62 is reduced, so that uneven application of the lubricant to the photoreceptor surface occurs. Can be suppressed. When the pressure P is increased, the amount of the lubricant applied to the photoreceptor surface increases.
By setting the density of the bristles to 20,000 hairs / 645.16 mm ² or more, the value of the pressure P can be reduced, thereby making it possible to reduce the amount of the lubricant used.

Table 3 shows the experimental results of examining the change in the density unevenness of the image on the recording medium when the amount of penetration δ of the brush 62 into the photosensitive member surface was changed. At this time, the density of the brush bristles was 20,000 / 645.16 mm ² , and the solid lubricant 6
The pressure P at which the brush 5 contacts the brush 62 is 400 mN, the rotational speed of the lubricant application member 60 is 110 rpm, and the linear velocity of the photosensitive member surface is 96 mm / sec.

[0058]

[Table 3]

As can be seen from Table 3, if the biting amount δ of the brush 62 is 1 mm or less, that is, 0 mm <δ ≦ 1 mm,
It can be understood that density unevenness of the image does not occur. As described above, the density of the bristles of the brush 62 is set to 20,000 / 645.16 mm.
^When it is set to ² or more, the smaller the biting amount δ of the brush 62, the more uniformly the lubricant can be applied to the surface of the photoreceptor, thereby extending the life of the lubricant application member.

Next, Table 4 shows the experimental results of examining the density unevenness of the image on the recording medium 22 when the rotation speed R of the lubricant application member 60 was changed. The brush 62 at this time
Hair density is 20,000 hairs / 645.16 mm ² , solid lubricant 6
The pressure P at which the brush 5 is pressed against the brush 62 is 400 mN, the amount of penetration of the brush 62 into the surface of the photoreceptor is 1 mm, and the linear velocity on the surface of the photoreceptor is 96 mm / sec.

[0061]

[Table 4]

From Table 4, it can be understood that when the rotational speed of the lubricant application member 60 is in the range of 55 to 220 rpm, the unevenness in image density can be suppressed. in this way,
The planting density of the bristles of the brush 62 is 20,000 / 645.16 mm ²
With the above setting, even if the rotational speed R of the lubricant application member is set to be low, uneven application of the lubricant can be suppressed, and the life of the lubricant application member 60 can be extended.

From the above experimental results, the lubricant application member 60
It can be understood that by setting the density of the bristles of the brush 62 to 20,000 / 645.16 mm ² or more, the amount of lubricant used can be suppressed and the life of the lubricant application member can be extended.

More specifically, the lubricant application member 60
The brush planting density of the brush 62 is 20,000 / 645.16 mm
^The number of rotations of the lubricant application member is R, the amount of penetration of the brush of the lubricant application member into the surface of the image carrier is δ, and the pressure at which the solid lubricant that the brush contacts comes into contact with the brush. Is P, 55 rpm ≦ R ≦ 220 rpm,
The respective values are set so as to satisfy 0 mm <δ ≦ 1 mm and 0 mN <P ≦ 400 mN, respectively.

In the illustrated image forming apparatus, the transfer device including the transfer brush 18 transfers the toner image to the transfer material including the intermediate transfer belt 16 with respect to the rotation direction of the image carrier including the photosensitive member 8. Transfer unit 17
The brush 62 of the lubricant applying member 60 is brought into contact with the surface of the image carrier that is further downstream than the cleaning unit that cleans the surface of the image carrier by a cleaning member including the cleaning blade 19. The position at which the brush 62 of the lubricant application member 60 contacts the surface of the photoreceptor can be set to an appropriate position other than the above-mentioned position as long as the position does not disturb the toner image on the photoreceptor surface. The lubricant can be applied to the surface of the photoconductor 8 even when the brush 62 is brought into contact with the surface of the photoconductor downstream of the cleaning blade 19 in the rotation direction of the photoconductor 8.

As described above, the position at which the brush is brought into contact with the surface of the photoreceptor can be set as appropriate, considering only that the lubricant is applied to the surface of the photoreceptor. When the position of the lubricant application member 60 is determined,
The brush 62 does not have the function of partially scraping off the transfer residual toner on the surface of the photoconductor, and the secondary effect that the efficiency of cleaning the surface of the photoconductor can be improved can be obtained.

However, according to this configuration, the transfer residual toner on the photoreceptor surface is always scraped off by the brush 62, and when the brush 62 comes into contact with the solid lubricant 65, the brush 62
A portion of the untransferred toner adhered to the surface is scraped off from the brush 62. At this time, since the illustrated image forming apparatus has the lubricant holding member 64 that holds the solid lubricant 65 with which the brush 62 contacts, the transfer residual toner scraped off from the brush 62 is The toner is blocked by the member and accumulates on the upper end surface 65a (FIG. 3) of the solid lubricant 65, and the accumulated toner adheres to the upper end surface 65a of the solid lubricant 65 and the brush itself over time due to the powder pressure of the toner. Then, the toner scatters again, which may cause uneven application of the lubricant to the surface of the photoconductor.

Therefore, in the image forming apparatus of this embodiment,
As shown in FIGS. 3 and 4, an opening 66 through which the transfer residual toner scraped from the surface of the image carrier made of the photoconductor 8 by the brush 62 of the lubricant application member 60 passes through the lubricant holding member 64 is formed. Are formed on the lubricant holding member 64. The transfer residual toner attached to the brush 62 is transferred to the brush 6
The solid lubricant 65 is scraped off from the brush 62 by hitting the solid lubricant 65, and the solid lubricant 65 is passed through the opening 66 formed in the lubricant holding member 64 as shown by an arrow F in FIG. It is possible to escape to the side of the lubricant holding member 64 opposite to the held surface, and it is possible to prevent the transfer residual toner from being deposited on the upper end surface 65 a of the solid lubricant 65. As a result, even when the image forming apparatus is used for a long period of time, the above-described problem can be prevented from occurring, and the lubricant can be more uniformly applied to the surface of the photoconductor.

Further, in the image forming apparatus described above, as shown in FIGS. 5 and 6, a plate-shaped brush contact member 67 that contacts the brush 62 of the lubricant applying member 60 is fixedly arranged, and the brush contact is provided. When the tip of the contact member 67 is brought into contact with the brush 62 over the entire length of the lubricant application member 60, the transfer residual toner attached to the brush 62 can be scraped off by the brush contact member 67. . For this reason, the amount of adhesion of the transfer residual toner is extremely small, or the portion of the brush 62 to which substantially no toner adheres can be brought into contact with the surface of the photoconductor. With this, brush 6
2 can improve the cleaning property of the photoreceptor surface, suppress the occurrence of a filming phenomenon in which the toner is fixed in a filming state on the photoreceptor surface, and further enhance the image quality of the toner image formed on the photoreceptor surface It becomes possible.

Although it has been described above that the transfer residual toner is not uniformly attached to the surface of the photoreceptor, the transfer residual toner adhered to the brush 62 is also uniform over the entire length of the brush 62. Therefore, such a brush 6
When 2 comes into contact with the photoreceptor surface again, the amount of the lubricant applied to the photoreceptor surface may become non-uniform. However,
When the brush contact member 67 is provided as described above, the brush 6
2 can be evenly dispersed in the longitudinal direction of the lubricant applying member 60, so that the brush 62
This makes it possible to apply the lubricant more evenly to the surface of the photoreceptor.

At this time, as shown in FIGS. 5 and 6, with respect to the rotational direction of the lubricant
A brush 62 that is located downstream of a portion that contacts the surface of the image bearing member made of the photoconductor 8 and that is upstream of a portion where the brush 62 contacts the solid lubricant 65.
When the brush contact member 67 is brought into contact with the brush contact member 6, the brush contact member 6 contacts the brush portion to which a relatively large amount of residual toner adheres.
7, the effect of uniformly dispersing the toner attached to the brush 62 can be enhanced.

In the examples shown in FIGS. 5 and 6, the brush contact member 67 is formed integrally with the lubricant holding member 64, thereby reducing the number of parts and reducing the cost of the image forming apparatus. Can be achieved. However, when this configuration is adopted, the brush 62 is
A portion of the transfer residual toner scraped from the toner accumulates on the brush contact member 67, which sticks with time, and scatters, which may cause uneven application of the lubricant on the surface of the photoreceptor. There is.

Therefore, in the example shown in FIGS. 5 and 6, the opening 68 through which the transfer residual toner scraped off from the surface of the image carrier composed of the photoreceptor 8 by the brush 62 of the lubricant applying member 60 passes. , Formed on the brush contact member 67. With such a configuration, the toner scraped off from the brush 62 passes through the opening 68 of the brush contact member 67.
, The accumulation of the transfer residual toner on the brush contact member 67 can be suppressed, and the above-described problem can be prevented from occurring.

In the above, the example in which the lubricant is applied to the surface of the image bearing member made of the photosensitive member has been described. For example, the lubricant is applied to the surface of the intermediate transfer member made up of the intermediate transfer belt 16 shown in FIGS. The present invention can also be applied to an image forming apparatus for coating. In this case, an image carrier on which a toner image is formed on the surface thereof while being driven to rotate is constituted by, for example, an intermediate transfer member including an intermediate transfer belt 16, and a transfer material onto which the toner image is transferred is a recording medium 22. Consisting of A transfer device that transfers the toner image onto a transfer material is constituted by, for example, the transfer roller 26 illustrated in FIG. 1, and removes transfer residual toner attached to the surface of the image carrier after the transfer of the toner image.
The cleaning member for cleaning the surface of the image carrier is constituted by, for example, the cleaning blade 32 shown in FIG. In such an image forming apparatus, a lubricant applying member that applies a lubricant to the surface of the image carrier has a brush that contacts the surface of the image carrier, and is not driven to rotate.
It is provided similarly to the lubricant application member 60 illustrated in FIGS. 1 to 6. The lubricating member is configured in exactly the same manner as described above with reference to the lubricating member 60.

However, as described above, when toner images of different colors are sequentially transferred onto the intermediate transfer belt in a superimposed manner, when each toner image passes through the portion of the lubricant applying member, the lubricant It is necessary to separate the application member from the intermediate transfer belt so that the toner image is not disturbed. The brush of the lubricant applying member is brought into contact with the surface of the intermediate transfer belt at a timing when the toner image is not likely to be disturbed, and the lubricant is applied to the surface. Thus, the present invention
When adopting a configuration in which a lubricant is applied to the intermediate transfer body of the color image forming apparatus, it is necessary to provide a contact / separation unit for bringing the lubricant application member into and away from the intermediate transfer body.

As the intermediate transfer member, a transfer drum for clamping a recording medium as a final transfer material can be used.
A toner image is transferred from the photoconductor to the surface of the recording medium wound around the transfer drum.

The present invention can be applied to an image forming apparatus in which a lubricant is applied to both surfaces of a photoreceptor and an intermediate transfer member without any trouble. The present invention can be widely applied to a forming apparatus. In addition, the present invention can be widely applied to image forming apparatuses other than the color image forming apparatus, image forming apparatuses that do not have an intermediate transfer member, and directly transfer a toner image from a photosensitive member to a recording medium that is a final transfer material.

[0078]

According to the first aspect of the present invention, the number of rotations of the lubricant applying member is kept low, and the amount of the brush penetrated into the surface of the image carrier is reduced, and the surface of the image carrier is uniformly lubricated. It is possible to apply a lubricant, thereby suppressing the occurrence of density unevenness of an image, improving the image quality, and extending the life of the lubricant application member.

According to the invention described in claim 2, according to claim 1
The effects of the invention described in (1) can be more reliably achieved.

According to the third aspect of the present invention, it is possible to prevent the transfer residual toner scraped off from the surface of the image bearing member by the brush from being deposited on the solid lubricant, and the lubricant on the surface of the image bearing member can be prevented from being deposited. The coating uniformity can be further improved.

According to the fourth aspect of the present invention, since the transfer residual toner attached to the brush can be scraped off by the brush contact member, the cleaning efficiency of the surface of the image carrier can be improved, and the surface of the image carrier can be improved. The occurrence of toner filming can be suppressed, and the amount of transfer residual toner adhered to the brush can be evened out, so that the lubricant can be more uniformly applied to the surface of the image carrier, and the image density can be improved. The occurrence of unevenness can be more reliably prevented.

According to the fifth aspect of the present invention, the amount of the transfer residual toner attached to the brush can be more reliably leveled, and the uneven application of the lubricant to the surface of the image carrier can be more reliably performed. Thus, the occurrence of image density unevenness can be more effectively suppressed.

According to the sixth aspect of the present invention, it is possible to prevent the transfer residual toner from depositing on the brush contact member, thereby more effectively preventing uneven application of the lubricant to the surface of the image carrier. be able to.

[Brief description of the drawings]

FIG. 1 is a cross-sectional front view illustrating an example of an image forming apparatus.

FIG. 2 is a sectional view showing an internal structure of a process unit.

FIG. 3 is a partially enlarged view of FIG. 2;

FIG. 4 shows the lubricant holding member and the solid lubricant shown in FIG.
It is the figure seen from the lubricant application member side.

FIG. 5 is a view similar to FIG. 3, showing an example in which a brush contact member is provided.

FIG. 6 shows a brush contact member shown in FIG.
It is the figure seen in the direction.

FIG. 7 is a diagram illustrating the amount of engagement of a brush.

FIG. 8 is a diagram illustrating the amount of penetration of a brush.

[Explanation of symbols]

 17 Transfer unit 60 Lubricant application member 62 Brush 64 Lubricant holding member 65 Solid lubricant 66 Opening 67 Brush contact member 68 Opening

Claims (6)

[Claims] An image carrier having a toner image formed on the surface thereof while being rotated, a transfer device for transferring the toner image to a transfer material, and a transfer residual toner adhered to the surface of the image carrier after the transfer of the toner image A cleaning member for cleaning the surface of the image carrier by removing the toner, and a lubricant applying member having a brush for contacting the surface of the image carrier and applying a lubricant to the surface of the image carrier while being driven to rotate. In the image forming apparatus, the density of the bristles of the brush of the lubricant applying member is 20,000 / 64.
5. An image forming apparatus characterized in that the size is not less than 16 mm ² . 2. The rotational speed of the lubricant application member is R, the amount of penetration of the brush of the lubricant application member into the surface of the image carrier is δ, and the pressure at which the solid lubricant that the brush contacts comes into contact with the brush. When P, 55 rpm ≦ R ≦ 220 rpm, 0 mm <
The image forming apparatus according to claim 1, wherein δ ≦ 1 mm and 0 mN <P ≦ 400 mN. 3. The cleaning device according to claim 1, further comprising: a cleaning unit configured to transfer a toner image to a transfer material by the transfer device, wherein the cleaning unit cleans a surface of the image carrier. The brush of the lubricant application member contacts the surface of the image carrier on the upstream side, and has a lubricant holding member for holding a solid lubricant with which the brush contacts, and the image is formed by the brush of the lubricant application member. 3. The image forming apparatus according to claim 1, wherein an opening through which the residual toner scraped off from the surface of the carrier passes through the lubricant holding member is formed in the lubricant holding member. 4. A cleaning unit for cleaning a surface of the image carrier by the cleaning member, the downstream side of a transfer unit for transferring a toner image to a transfer material by the transfer device in the rotation direction of the image carrier. The brush of the lubricant applying member comes into contact with the surface of the image carrier on the upstream side, and has a lubricant holding member for holding a solid lubricant with which the brush comes into contact. The image forming apparatus according to claim 1, further comprising a brush contact member that comes into contact with the image forming apparatus. 5. In the rotation direction of the lubricant applying member, the brush of the lubricant applying member is located on the downstream side of a portion where the brush contacts the surface of the image carrier, and is located at a position lower than a portion where the brush contacts the solid lubricant. The image forming apparatus according to claim 4, wherein the brush contact member contacts an upstream brush portion. 6. The brush contact member is formed integrally with a lubricant holding member, and the brush contact member passes through an opening through which the transfer residual toner scraped from the surface of the image carrier by the brush of the lubricant applying member passes. The image forming apparatus according to claim 4, wherein the image forming apparatus is formed in the image forming apparatus.