JP2000155475A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To restrain generation of abrasion scratch on a photoreceptor and an intermediate transfer belt. SOLUTION: In this image forming device, the intermediate transfer belt 9 is provided with a rubber layer which is ground. When the surface velocity of the photoreceptor 1 and the intermediate transfer belt 9 at a primary transfer nip part N1 are different, respectively V1 and V2, and the surface velocity of the intermediate transfer belt 9 and transfer material P are different at a secondary nip part N2, respectively V3 and V4, V1<V2 and |V3-V4|<|V1-V2| are satisfied. Since the ground trace of the intermediate transfer belt at the primary nip part N1 is directed toward the direction of rotation of the photoreceptor 1, generation of scratches on the photoreceptor 1 and the intermediate transfer belt 9 can be prevented.

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 using an electrophotographic system such as a copying machine, a printer, a facsimile, etc., and more particularly to an image forming apparatus using an intermediate transfer member.

[0002]

2. Description of the Related Art Conventionally, various types of image forming apparatuses, such as an electrophotographic type, a thermal transfer type, and an ink jet type, are known. Of these, the electrophotographic type is replaced with another type. In comparison, they are superior in terms of image forming speed, image quality, quietness, and the like.

[0003] Among the image forming apparatuses adopting the electrophotographic system, there are further various types. For example, a multi-development method in which a plurality of color toner images are sequentially overlaid and transferred onto the surface of a photoreceptor and then a plurality of color toner images are collectively transferred to a transfer material to form an image, A multi-transfer method in which a toner image of a plurality of colors is formed on a transfer material by repeatedly performing a process of transferring to a transfer material, or a process in which a toner image formed on a photoreceptor surface is repeatedly transferred to an intermediate transfer body by a plurality of colors After the toner image is formed on the intermediate transfer member, there is an intermediate transfer method in which a plurality of color toner images are collectively transferred from the intermediate transfer member to a transfer material. Among them, the intermediate transfer method has the advantages that there is no risk of color mixing and that various transfer materials having different qualities and thicknesses can be used.

FIG. 5 schematically shows a four-color full-color laser beam printer as an example of an intermediate transfer type image forming apparatus.

As shown in FIG. 5, around the photosensitive drum 1 serving as an image carrier, a charger 2 and an exposure for irradiating a laser beam to the surface of the photosensitive drum 1 are sequentially arranged in the rotation direction (the direction of arrow R1). A device 3, a developing device 5, an intermediate transfer belt 9 as an intermediate transfer body, and a cleaner 19 for cleaning the photosensitive drum 1 are arranged.

Specifically, the surface speed V1 is 118 m in the direction of arrow R1.
The photosensitive drum 1 having a diameter of 46.7 mm, which is driven to rotate at m / sec,
The surface is negatively charged by the charger 2. A charging bias in which a DC voltage is superimposed on an alternating voltage is applied to the charger 2 by a power supply 17, and the potential on the surface of the photosensitive drum 1 (hereinafter, charging potential) is charged to -450v to -800v. By using a charging bias in which a DC voltage is superimposed on an alternating voltage, charging can be performed efficiently. An electrostatic latent image is formed on the surface of the charged photosensitive drum 1 by exposure L of the exposure unit 3 according to image information. This electrostatic latent image is reversely developed as a black toner image by using a black toner of negative polarity by the first black developing device 5 mounted on the rotary 22. Intermediate transfer belt 9
(Hereinafter, ITB 9) is supported by a plurality of support shafts (secondary transfer opposing roller 12, drive roller 15, tension roller 16). And it has a rubber layer on the surface, diameter 28mm
With the rotation of the drive roller 15 (in the direction of the arrow R2 in the figure), the ITB 9 rotates in the direction of the arrow R3 in the figure. And
12m in diameter that rotates following ITB9 (direction of arrow R5 in the figure)
When a positive primary transfer bias is applied from the power supply 20 to the primary transfer roller 10m, the toner image on the photosensitive drum 1 is primarily transferred to the ITB 9 at the primary transfer nip N1. At this time, the surface speed V2 of the ITB 9 in the primary transfer nip N1 is defined by the diameter of the drive roller 15, and
9 mm / sec. IT at the primary transfer nip N1
Making the B9 surface speed V2 higher than the surface speed V1 of the photosensitive drum 1 is effective in improving the primary transfer efficiency, preventing the occurrence of missing during transfer, and stabilizing the rotation of the photosensitive drum 1 and the ITB 9. The outer diameter of the driving roller 15 is adjusted by polishing a surface layer made of rubber. Further, as the primary transfer roller 10, a resistance adjuster such as carbon is added to a material such as EPDM (terpolymer of ethylene propylene diene), urethane rubber, CR (chloroprene rubber), NBR (nitrile butadiene rubber), Volume resistivity
Adjusted to 10 ⁵ Ω · cm or less. Then, by polishing the surface of a member obtained by winding this material around a cored bar, it is processed into a desired external dimension, and the primary transfer roller 10 is obtained. The primary transfer residual toner on the surface of the photosensitive drum 1 after the primary transfer is removed by the cleaner 19 having the elastic blade 191.

The above-described series of image forming processes of charging, exposure, development, primary transfer, cleaning, and charge elimination are performed by the second color magenta, the third color cyan, and the fourth color stored in the developing units 6, 7, and 8, respectively. This process is repeated for the yellow toner, and the four color toner images are sequentially transferred onto the ITB 9 in a superimposed manner. At that time, the surface of the ITB 9 is gradually charged to the negative polarity every time the primary transfer is performed. Therefore, in order to efficiently perform the primary transfer, for example, +100 v for the first color and + for the second color
The primary transfer bias is gradually increased for each color so that 500 V, the third color is +600 V, and the fourth color is +700 V.

The transfer material P is transferred to the secondary transfer nip portion N2 at a predetermined timing with a surface speed V4 of 122.8 mm /
Is fed and transported in seconds, and has a peripheral speed of 122.8 mm /
Power supply to the φ20 mm secondary transfer roller 11
When a secondary transfer bias is applied from 21, the toner images of a plurality of colors on the ITB 9 are secondarily transferred to the transfer material P at once. At this time, the ITB 9 in the secondary transfer nip N2
Has a surface speed V3 of 122 mm / sec.
The surface speed of the transfer material P is set to the value I at the secondary transfer nip N2.
The speed is set higher than the surface speed of the TB9 to improve the secondary transfer efficiency, prevent the occurrence of missing during transfer, and stabilize the running of the transfer material P and the ITB9. The portion of the ITB 9 wound around the secondary transfer facing roller 12 extends, and the surface speed of the ITB 9 increases according to the amount of the extension.

The transfer material P on which the unfixed toner images of four colors have been transferred to the surface is conveyed to a fixing device (not shown), where the toner image on the surface is fixed to complete the image formation.

On the other hand, after the completion of the secondary transfer, the ITB 9 removes the secondary transfer residual toner remaining on the ITB 9 without being transferred to the transfer material P by the cleaner 13 and, if necessary, a charge removing charger (a charge removing means). The charge is removed by 14. As the static eliminator 14, it is preferable to use AC corona charging. Further, an electrode facing the static eliminator 14 may be provided inside the ITB 9 in order to increase the static elimination efficiency.

The ITB 9 uses an elastic material (chloroprene rubber, EPDM, NBR, urethane rubber, etc.) having a thickness of about 0.5 to 2.0 mm as a material, and uses ZnO, SnO2, T
10 ⁷ to 10 ¹¹ Ω · due to iO2 and other conductive fillers
The volume resistance is adjusted to about cm. In this way ITB9
, The image defect due to the accumulation of electric charges in the ITB 9 can be prevented.

On the other hand, in order to process the elastic material to a desired thickness, polishing is performed with a grindstone.

As described above, when the primary transfer peripheral speed ratio is (V2 / V1) and the secondary transfer peripheral speed ratio is (V4 / V3), in the image forming apparatus, (V2 / V1)> (V4 / V3), but (V1 / V2)> (V3 / V4) may be satisfied. Also in this case, the transfer efficiency is improved, the occurrence of omission during transfer is prevented, and the running of the photosensitive drum 1, the ITB 9, and the transfer material P is stabilized.

[0014]

However, the above-mentioned prior art has the following problems. That is, shortly after using the apparatus from a new state, the photosensitive drum 1
In addition, scratches were generated on the surface of ITB9 and the image quality was sometimes reduced.

According to the study by the present inventors, the occurrence of this flaw is determined by the primary transfer peripheral speed ratio (V2 / V1) and the secondary transfer peripheral speed ratio (V
4 / V3), and it was found to be caused by the hooking caused by the direction of the polished line on the ITB9 surface.

In the manufacturing process, the surface of the ITB 9 is polished in order to process it to a desired thickness. FIG. 6 shows an example of a method of polishing the surface of the ITB 9. I supported by two rollers
The surface of the TB9 is shown by an arrow R in FIG.
Rotate in y direction, opposite direction to ITB9 (arrow Rx direction)
The surface is polished by a whetstone that rotates. The polished surface of the polished surface is determined by the polishing direction (the traveling direction of the grindstone when polishing is performed). In the case of the polishing direction shown in FIG. 6, the polished surface is as shown in FIG. The direction of the polished eye determines the catch at the time of rubbing the surfaces of the photosensitive drum 1 and the ITB 9. That is, as shown in FIGS. 8A and 8B, when a certain weight is placed on the polished surface and slid and moved, the catch in FIG. 8B becomes larger than that in FIG. 8A.

The scratches on the surfaces of the photosensitive drum 1 and the ITB 9 which occur at the primary transfer nip N1 occur at the polished eyes in the direction in which the hooking increases, and the degree of the abrasion deteriorates in proportion to the difference in the peripheral speed. .

FIG. 9 is a detailed view showing the vicinity of the primary transfer nip portion N1 of a conventional image forming apparatus. The relationship between the primary transfer peripheral speed ratio and the secondary transfer peripheral speed ratio is (V2 / V1)> (V4 / V
3) And (V2 / V1)> 1.0. At this time, at the primary transfer nip portion N1 having a large peripheral speed ratio, the surface of the photosensitive drum 1 and the surface of the ITB 9 were abraded due to a polished grain having a large catch.

In another conventional example, (V1 / V2)>
When (V3 / V4) and (V3 / V4)> 1.0, the ITB9 surface at the secondary transfer nip portion N2 has
As shown in FIG. 10, it was in the direction of large catching.
In this conventional example, the secondary transfer nip portion N2 having a large peripheral speed difference is used.
And the scratches became large on the surface of ITB9.

Further, as another problem, as the transfer material P,
When smooth paper such as glossy paper was used, a slip occurred between the secondary transfer roller and the transfer material P, and a jam occurred. According to the study, the cause of the slip was the magnitude of the catch due to the direction of the polished eyes of the secondary transfer roller.

FIG. 11 shows an example of a method for polishing the roller surface. In FIG. 11, the roller rotating in the direction of the arrow Rk is polished with a cylindrical grindstone rotating in the direction Rl opposite to the roller,
It is processed to a desired outer diameter. At this time, when polishing is performed in the direction shown in FIG. 11, the polishing direction of the surface is as shown in FIG.

When the roller having the polished eye shown in FIG. 13 is rotated in the directions of arrows a and b, the catch on the abutting sheet is greater when the roller is rotated in the direction of arrow b. The transport force of P also increases.

FIG. 14 is a detailed view showing the vicinity of the surface of the secondary transfer roller 11 in the conventional example. Secondary transfer roller
11 The polished surface of the surface is in a direction in which the transfer material P is not easily caught by the transfer material P, and the conveying force is small. Therefore, glossy paper or the like having a small dynamic friction force between the surface of the secondary transfer roller 11 and the surface of the transfer material P is not conveyed, and a jam occurs.

As another problem, when a small amount of toner adheres to the back surface of the ITB 9 due to slight scattering of toner in a high-temperature and high-humidity environment, the driving roller
There was a problem that slippage occurred between the back surface of the TB9 and the rotation of the ITB9 became unstable.

This is also because, as shown in FIG. 15, the polished surface of the drive roller 15 whose surface has been polished is in the direction in which the back surface of the ITB 9 is hardly caught. If a small amount of toner adheres to the back surface of the ITB 9, the dynamic frictional force between the back surface of the ITB 9 and the front surface of the drive roller 15 becomes small, and if the drive roller 15 is not easily caught by polishing, slip occurs.

Another problem is that, similarly, when a small amount of toner adheres to the back surface of the ITB 9 due to slight scattering of toner in a high-temperature, high-humidity environment, the primary transfer roller 10 moves between the ITB 9 and the back surface. Slip occurred, and the surface of the primary transfer roller 10 was worn. Primary transfer roller 10 and I
When a slip occurs between the back surfaces of the TB9, the primary transfer roller
10 is rubbed and worn by ITB9. In the apparatus shown in the conventional example, the polished surface of the primary transfer roller 10 whose front surface has been polished was, as shown in FIG. As in the case of the drive roller 15 described above, if the polished stitch of the primary transfer roller 10 is in the direction in which the catch is small, the kinetic frictional force between the back surface of the ITB 9 and the surface of the primary transfer roller 10 is reduced due to the adhesion of the toner. In the sample No. 9, slip occurred on the back surface of ITB9.

In view of the above, it is an object of the present invention to suppress the occurrence of scratches on the surface of the intermediate transfer member and the image carrier. Another object of the present invention is to prevent a transfer material from being jammed. Another object of the present invention is to
The object is to stabilize the rotation of the intermediate transfer member and the first transfer means. It will become apparent from the following detailed description read in conjunction with the accompanying drawings.

[0028]

According to the present invention, the above object is achieved. According to the present invention, there is provided a rotatable image carrier for carrying a toner image, and a rotatable intermediate transfer body on which the toner image on the image carrier is transferred at a first transfer position. In an image forming apparatus in which a toner image on a transfer body is transferred to a transfer material at a second transfer position, the intermediate transfer body has at least a polished polishing layer;
The surface speeds of the image bearing member and the intermediate transfer member at the transfer position are different from each other, and are V1 and V2.
The surface velocities of the intermediate transfer body and the transfer material at the transfer position are different from each other, and when V3 and V4, V1 <V
2, and | V3-V4 | <| V1-V2 |
The polishing pattern of the intermediate transfer member at the first transfer position is the first in the rotation direction of the image carrier.

According to another embodiment of the present invention, a rotatable image carrier for carrying a toner image, and a rotatable intermediate transfer for transferring the toner image on the image carrier at a first transfer position And an image forming apparatus in which the toner image on the intermediate transfer member is transferred to a transfer material at a second transfer position, wherein the intermediate transfer member has at least a polished polishing layer; The surface speeds of the image bearing member and the intermediate transfer member at the first transfer position are different from each other, V1 and V2, and the surface speeds of the intermediate transfer member and the transfer material at the second transfer position are different from each other. V4 <V3 and | V1-V2 | <| V3-V4
Is established, and the polishing line of the intermediate transfer body at the second transfer position is the first in the transport direction of the transfer material.

According to still another embodiment, a rotatable image carrier for holding a toner image, a rotatable intermediate transfer member, and the intermediate transfer member abutting on a side of the intermediate transfer member not holding the toner image. A first transfer unit rotatable with respect to the body, the first transfer unit transferring a toner image on the image carrier at a first transfer position; and a toner image on the intermediate transfer body. Is an image forming apparatus that is transferred to a transfer material at a second transfer position, wherein the first transfer means has at least a polished polishing layer, and the first transfer means has a polished eye on the intermediate transfer member. It is characterized by being opposite to the rotation direction of the back surface.

According to still another embodiment, a rotatable image carrier for carrying a toner image, a rotatable intermediate transfer body for transferring the toner image on the image carrier at a first transfer position, A second transfer means capable of abutting the toner image bearing side of the intermediate transfer body, the second transfer means being capable of transferring the toner image on the intermediate transfer body to a transfer material at a second transfer position. Wherein the second transfer means has at least a polished polishing layer, and the polished eyes of the second transfer means are in the direction of rotation of the surface of the intermediate transfer body. On the other hand, it is characterized by being a reverse order.

According to still another embodiment, a rotatable image carrier for carrying a toner image, an intermediate transfer belt on which the toner image on the image carrier is transferred at a first transfer position,
An image forming apparatus comprising: a driving unit that rotates the intermediate transfer belt in contact with the back surface of the intermediate transfer belt, and the toner image on the intermediate transfer belt is transferred to a transfer material at a second transfer position. The driving means has at least a polished polishing layer, and a polishing edge of the driving means is opposite to a rotation direction of a back surface of the intermediate transfer belt.

[0033]

(Embodiment 1) FIG. 1 is a schematic diagram showing an image forming apparatus according to a first embodiment of the present invention. Note that the same members as those of the conventional image forming apparatus shown in FIG. 4 are denoted by the same reference numerals, and redundant description will be omitted.

This image forming apparatus uses the ITB 9 according to this embodiment.
The configuration other than the above is the same as the conventional example shown in FIG. 5, and the image forming operation is performed in the same manner as in the above-described conventional image forming apparatus. In this embodiment, the description of the image forming operation is omitted.

The surface speed V1 of the photosensitive drum 1 at the primary transfer portion N1 is 117 mm / sec, and the surface speed V2 of the ITB 9 is
Is 118 mm / sec, the surface speed V3 of the ITB 9 at the secondary transfer portion N2 is 122 mm / sec, and the surface speed V4 of the transfer material P is 12
2.8 mm / sec. That is, V1 and V2 are set to different speeds, and V3 and V4 are set to different speeds to prevent transfer omission at the time of primary and secondary transfer and to improve transfer efficiency. As shown in FIG. 1, the primary transfer nip N
1, the rotation direction of the photosensitive drum 1 and the ITB 9 is the forward direction, and the rotation direction of the ITB 9 and the transfer material P (the secondary transfer roller 11) in the secondary transfer nip N2 is also the forward direction.

Here, as ITB9, JIS-A hardness is 55
The degree of epichlorohydrin rubber used was adjusted so that the volume resistivity was about 10 ⁸ Ω · cm. This rubber is processed into a cylindrical shape, and is polished by a polishing means (polishing roller) shown in FIG.
Polish the ITB9 surface in the direction parallel to the direction of rotation and reduce the thickness to 0.
It was adjusted to 8 mm.

In this embodiment, V1 <V2 and | V3-
V4 | <| V1-V2 |. And FIG.
In the middle, the polishing line on the surface of the ITB 9 is first in the rotation direction of the surface of the photosensitive drum 1 in the primary transfer nip portion N1. The reason for setting the upper limit to 1.05 is that the so-called color misregistration in which the toner images of the respective colors do not overlap correctly in the primary transfer cannot be ignored. The reason for setting the lower limit to 0.95 is that the rotation of the ITB 9 affects the conveyance of the transfer material P, and in the worst case, the conveyance becomes unstable, and a jam may occur. Furthermore, in an image forming apparatus that performs primary transfer of the next image simultaneously with secondary transfer, there is a possibility that a color shift (color shift between the first color and the second and subsequent colors) in the primary transfer may occur.

Therefore, the surface of the ITB 9 is less likely to be caught on the surface of the photosensitive drum 1 at the primary transfer nip portion N1 having a large peripheral speed ratio, and the occurrence of scratches on the surface of the ITB 9 and the surface of the photosensitive drum 1 can be prevented. Further, by setting the respective speeds in a relationship of V1 <V2 <V3 <V4, it was possible to prevent the occurrence of a braking force on the ITB 9 and the occurrence of rotational drive unevenness.

The present invention is not limited to the above embodiment, but 0.95 <(V4 / V3) <1.0 and 1.0 <(V2 / V1) <1.05 (1) or 0.95 <( V4 / V3) <1.0 and 1.0 <(V2 / V1) <1.05 (2) Even if ITB9 is polished on the photosensitive drum 1,
It is preferable that the rotation direction of the surface is the first. If the expressions (1) and (2) are satisfied, the surface of the ITB 9 is less likely to be caught on the surface of the transfer material P, and the surface of the ITB 9 (or the transfer material P
Otherwise, it is possible to prevent scratches on the surface of the secondary transfer roller 10).

The present invention is not limited to the above embodiment, and the respective speeds may have a relationship of V1>V2>V3> V4.
In this case, a unidirectional force is applied to the rotational force of the ITB 9, so that it is possible to prevent the occurrence of rotational drive unevenness.

Although a single-layer rubber belt is used as the ITB 9 in this embodiment, a woven fabric or a thread may be provided in the rubber belt as a reinforcing member.

Further, even when the ITB 9 is coated with a thin resin layer on the rubber surface, the catch between the surface of the ITB 9 and the surface of the photosensitive drum 1 (the surface of the secondary transfer roller 10) is similar to that described above. It changes according to the direction. The thickness of the resin layer is preferably 1 to 200 μm. Also,
The present invention is similarly effective in the case where a fluorine resin or the like is coated in order to improve the cleaning property of the secondary transfer residual toner remaining on the ITB 9 after the secondary transfer.

(Embodiment 2) FIG. 2 is a view showing a primary transfer nip portion N1 and a secondary transfer nip portion N2 of an image forming apparatus according to this embodiment. The ITB in the photosensitive drum 1, the primary transfer nip N1, and the secondary transfer nip N2
9. Embodiment 1 shown in FIG. 1 except for the surface speed of the transfer material P
This embodiment is the same as the image forming apparatus described above, and the description of the other components and the image forming operation is omitted in this embodiment.

In the primary transfer portion N1, the surface speed V1 of the photosensitive drum 1 is 117 mm / sec, and the surface speed V2 of the ITB 9 is
117.5 mm / sec, the surface speed V3 of the ITB 9 in the secondary transfer portion N2 was 122 mm / sec, and the surface speed V4 of the transfer material P was 123.5 mm.
mm / sec. As shown in FIG. 2, the rotation directions of the photosensitive drum 1 and the ITB 9 in the primary transfer nip portion N1 are forward directions, and the rotation directions of the ITB 9 and the transfer material P (secondary transfer roller 11) in the secondary transfer nip portion N2. It is forward direction.

The ITB 9 has the same JI as in the first embodiment.
Epichlorohydrin rubber with SA hardness of 55 has a volume resistivity of 10 ⁸ Ω
The one adjusted to about cm was used. This rubber was processed into a cylindrical shape, and the surface of the ITB 9 was polished in a direction parallel to the rotation direction by a polishing means (polishing roller) shown in FIG. 6 to adjust the thickness to 0.8 mm.

In this embodiment, V4 <V3 and | V1
−V2 | <| V3-V4 |. And FIG.
In the middle, the polishing line on the surface of the ITB 9 is first in the secondary transfer nip portion N2 in the transport direction of the transfer material P.
The reason for setting the upper limit to 1.05 is that the so-called color misregistration in which the toner images of the respective colors do not overlap correctly in the primary transfer cannot be ignored. The reason for setting the lower limit to 0.95 is that the rotation of the ITB 9 affects the conveyance of the transfer material P, and in the worst case, the conveyance becomes unstable, and a jam may occur. Furthermore, in an image forming apparatus that performs primary transfer of the next image simultaneously with secondary transfer, there is a possibility that a color shift (color shift between the first color and the second and subsequent colors) in the primary transfer may occur.

Therefore, in the secondary transfer nip portion N2 having a large peripheral speed ratio, the surface of the ITB 9 is less likely to be caught on the transfer material P, and the surface of the ITB 9 and the transfer material P (the secondary transfer when rotating without passing through the transfer material P). The generation of scratches on the surface of the transfer roller 11) could be prevented. Further, by setting the respective speeds in a relationship of V1 <V <V3 <V4, it was possible to prevent the occurrence of a braking force on the ITB 9 and the occurrence of rotational drive unevenness.

The present invention is not limited to the above embodiment, but 0.95 <(V1 / V2) <1.0 and 1.0 <(V3 / V4) <1.05 (3) or 0.95 <( V2 / V1) <1.0 and 1.0 <(V3 / V4) <1.05 (4) Even if ITB9 is polished on the surface of the photosensitive drum 1,
It is preferable that the rotation direction of the surface is the first. If the above expression (3) or (4) is satisfied, the surface of the ITB 9 is less likely to be caught on the surface of the transfer material P, and the surface of the ITB 9 (or the transfer material P) is also present in the secondary transfer nip N2.
It is possible to prevent the occurrence of scratches on the secondary transfer roller 11 rotating without passing through).

The present invention is not limited to the above embodiment, and the respective speeds may have a relationship of V1>V2>V3> V4.
In this case, a unidirectional force is applied to the rotational force of the ITB 9, so that it is possible to prevent the occurrence of rotational drive unevenness.

Although a single-layer rubber belt is used as the ITB 9 in this embodiment, a woven fabric or a thread may be provided in the rubber belt as a reinforcing member.

Further, even when the rubber surface is coated with a thin resin layer as the ITB 9, the catch between the surface of the ITB 9 and the surface of the photosensitive drum 1 (the surface of the transfer material P or the secondary transfer roller 10) is the same as described above. In addition, it changes according to the direction of the polishing line. The thickness of the resin layer is preferably 1 to 200 μm. Further, the present invention is similarly effective in a case where a fluorine resin or the like is coated in order to improve the cleaning property of the secondary transfer residual toner remaining on the ITB 9 after the secondary transfer.

(Embodiment 3) FIG. 3 is a view showing the vicinity of a secondary transfer roller of an image forming apparatus according to this embodiment. In addition,
The components other than the secondary transfer roller 11 are the same as those of the image forming apparatus of the first embodiment shown in FIG. 1, and the description of the other components and the image forming operation will be omitted in this embodiment.

In this embodiment, in addition to optimizing the direction of the polished line, the polished line of the secondary transfer roller 11 is reversed with respect to the transfer material. This prevents the photosensitive drum 1 and the ITB 9 from being damaged, and prevents the occurrence of a jam when using a transfer material P such as glossy paper, which has a small dynamic friction coefficient with the surface of the secondary transfer roller 11. Prevented.

The secondary transfer roller 11 used in this embodiment is made of a conductive urethane rubber having an Asker C hardness of 30 ° and a volume resistivity of 10 °.
A material adjusted to about ⁷ Ω · cm was used. This rubber
It was wound around a SUS cored bar having a diameter of 8 mm, the surface thereof was polished by a polishing apparatus shown in FIG. 11, and formed into a roller having a diameter of 20 mm. Hardness of secondary transfer roller 11 (Asker C hardness)
In consideration of the durability due to the abrasion of the secondary transfer roller 11, it is preferably 20 degrees (650 g load) or more. In order to secure a sufficient secondary transfer nip N2 and prevent poor transfer,
It is preferably 5 (1 kg load) or less.

In the third embodiment, the running stability of the transfer material P can be improved, but it may be appropriately combined with the first or second embodiment. By appropriately combining, it is possible to further prevent the ITB 9 and the photosensitive drum 1 from being damaged. The secondary transfer roller 11 is rotatably driven by a drive mechanism (not shown), and is configured to be able to contact and separate from the ITB 9 by a contact and separation mechanism (not shown).

(Embodiment 4) FIG. 4 is a view showing the vicinity of a driving roller and a primary transfer roller of an image forming apparatus according to this embodiment. The primary transfer roller 10 and the driving roller 1
The configuration other than the configuration 5 is the same as that of the image forming apparatus of the first embodiment shown in FIG. 1, and the description of the other configuration and the image forming operation in this embodiment is omitted.

In the present embodiment, in addition to optimizing the polishing direction of the ITB 9, the polishing direction of the primary transfer roller that rotates following the ITB 9 is set opposite to the ITB 9, and the driving roller 15 The direction of the polished line was set opposite to the back surface of ITB9. Thereby, the photosensitive drum 1 and the IT
B9 was prevented from being damaged, and the primary transfer roller 10 and the driving roller 15 were prevented from slipping on the back surface of the ITB 9.

The primary transfer roller 10 used in this embodiment was made of a conductive EPDM foam having a degree of 35 degrees (Asker C hardness) adjusted to a volume resistivity of about 10 ³ Ω · cm. This material was wound around a SUS core having a diameter of 6 mm, and the surface thereof was polished with a polishing device shown in FIG.
mm.

The driving roller used in this embodiment is JIS
-A chloroprene rubber having a hardness of 60 degrees was used. This rubber was wound around a SUS cored bar having a diameter of 8 mm, the surface thereof was polished by a polishing device shown in FIG. 11, and formed into a roller having a diameter of 28 mm.

In the fourth embodiment, the running stability of the ITB 9 and the rotation stability of the primary transfer roller 10 can be improved. However, the fourth embodiment can be appropriately combined with the first to third embodiments. . By combining, ITB9,
It is also possible to prevent the photosensitive drum 1, the secondary transfer roller 11 and the like from being damaged.

In the first to fourth embodiments, the toner images of different colors formed on one photosensitive drum 1 are
Although the image forming apparatus has been described in which the toner images of multiple colors on the ITB 9 are transferred onto the transfer material P in a lump, the image forming apparatus is not limited to this. That is, a plurality of photosensitive drums (three or four in accordance with the number of toner colors) are provided, and toner images of different colors formed on the plurality of photosensitive drums are sequentially superimposed on the ITB 9 and transferred.
Needless to say, the present invention can also be applied to an image forming apparatus that collectively transfers a plurality of color toner images on the TB 9 to the transfer material P.

[0062]

According to the present invention, the intermediate transfer member has at least a polished polishing layer, and the surface speeds of the image carrier and the intermediate transfer member at the first transfer position are different from each other. , The surface speeds of the intermediate transfer member and the transfer material at the second transfer position are different from each other.
V1 <V2, and | V3-V4 | <| V
1-V2 | is satisfied, and since the polishing line of the intermediate transfer member at the first transfer position is in the order of the rotation direction of the image carrier, scratches occur on the surfaces of the intermediate transfer member and the image carrier. Can be prevented.

According to another embodiment of the present invention, the intermediate transfer body has at least a polished polishing layer, and the surface speeds of the image carrier and the intermediate transfer body at the first transfer position are different from each other. , V2, and the surface speeds of the intermediate transfer member and the transfer material at the second transfer position are different from each other.
3, V4, V4 <V3, and | V1-V2
| <| V3−V4 | is satisfied, and since the polishing line of the intermediate transfer member at the second transfer position is first in the conveying direction of the transfer material, scratches are generated on the surface of the intermediate transfer member. Can be prevented.

According to another embodiment of the present invention, the first transfer means has at least a polished polishing layer,
Since the polishing line of the transfer unit is opposite to the rotational direction of the back surface of the intermediate transfer body, the rotation of the first transfer unit can be stabilized.

According to yet another embodiment, the second transfer means has at least a polished polishing layer, and the polished eyes of the second transfer means are opposite to the rotational direction of the surface of the intermediate transfer member. Therefore, it is possible to prevent the transfer material from being jammed.

According to another embodiment of the present invention, the driving means for rotating the intermediate transfer belt in contact with the back surface of the intermediate transfer belt has at least a polished polishing layer,
Since the polishing line of the driving unit is opposite to the rotation direction of the back surface of the intermediate transfer belt, even if toner adheres to the back surface of the intermediate transfer belt, the driving unit is prevented from slipping and the rotation of the intermediate transfer belt is stabilized. Can be done.

[Brief description of the drawings]

FIG. 1 is a schematic diagram illustrating an image forming apparatus according to a first embodiment of the present invention.

FIG. 2 is a schematic view illustrating an image forming apparatus according to a second embodiment of the invention.

FIG. 3 is a schematic diagram illustrating an image forming apparatus according to a third embodiment of the invention.

FIG. 4 is a schematic diagram illustrating a conventional image forming apparatus.

FIG. 5 is a schematic diagram.

FIG. 6 is a schematic diagram illustrating an apparatus for polishing an intermediate transfer member.

FIG. 7 is a schematic view showing a polished pattern of an intermediate transfer member.

FIG. 8 is a comparison of the catch between the intermediate transfer member and the weight (a,
Schematic diagram representing b).

FIG. 9 is a schematic diagram illustrating a conventional image forming apparatus.

FIG. 10 is a schematic diagram illustrating a conventional image forming apparatus.

FIG. 11 is a schematic diagram illustrating an apparatus for polishing a primary transfer roller.

FIG. 12 is a schematic view showing a polishing line of a primary transfer roller.

FIG. 13 is a schematic diagram illustrating the catch between a primary transfer roller and a sheet.

FIG. 14 is a schematic diagram illustrating a conventional image forming apparatus.

FIG. 15 is a schematic diagram illustrating a conventional image forming apparatus.

FIG. 16 is a schematic diagram illustrating a conventional image forming apparatus.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Photosensitive drum 9 ITB 10 Primary transfer roller 11 Secondary transfer roller

Claims (38)

[Claims] 1. A rotatable image carrier for carrying a toner image, and a rotatable intermediate transfer member onto which a toner image on the image carrier is transferred at a first transfer position, wherein the intermediate transfer is performed. An image forming apparatus wherein a toner image on a body is transferred to a transfer material at a second transfer position, wherein the intermediate transfer member has at least a polished polishing layer, and the image carrier at the first transfer position And the surface velocities of the intermediate transfer member are different from each other, V1 and V2,
The surface speeds of the intermediate transfer body and the transfer material at the second transfer position are different from each other, and when V3 and V4, V1 <V2 and | V3-V4 | <| V1-V2 | The image forming apparatus according to claim 1, wherein a polishing line of the intermediate transfer member at the first transfer position is a first line in a rotation direction of the image carrier. 2. The image forming apparatus according to claim 1, wherein 0.95 <(V4 / V3) <1.0 and 1.0 <(V2 / V1) <1.05 are satisfied. 3. The image forming apparatus according to claim 1, wherein 0.95 <(V3 / V4) <1.0 and 1.0 <(V2 / V1) <1.05 are satisfied. 4. The image forming apparatus according to claim 1, further comprising a polishing layer that has been polished at least, and a rotatable first roller that transfers the toner image on the image carrier to the intermediate transfer member at the first transfer position. The image forming apparatus according to claim 1, further comprising a transfer unit, wherein the first transfer unit is driven to rotate by the intermediate transfer body, and a polishing edge of the first transfer unit is reverse to a back surface of the intermediate transfer body. Item 4. The image forming apparatus according to any one of Items 1 to 3. 5. The image forming apparatus according to claim 4, wherein said polishing layer is an elastic layer. 6. The image forming apparatus is a second transfer unit that includes at least a polished polishing layer and is capable of abutting on a side of the intermediate transfer body that carries the toner image, wherein the intermediate transfer body A rotatable second transfer unit for transferring the upper toner image onto the transfer material at the second transfer position, wherein the polishing surface of the second transfer unit is opposite to the back surface of the transfer material; The image forming apparatus according to claim 1, wherein: 7. The image forming apparatus according to claim 6, wherein the polishing layer is an elastic layer. 8. The image forming apparatus includes at least a polishing layer that has been polished, and has a driving unit that rotates while being in contact with the back surface of the intermediate transfer body. The image forming apparatus according to any one of claims 1 to 7, wherein the image forming apparatus has a reverse face with respect to the back of the body. 9. The image forming apparatus according to claim 1, wherein the polishing layer of the intermediate transfer member is an elastic layer. 10. The image forming apparatus according to claim 9, wherein said intermediate transfer member has a coating layer for coating said elastic layer. 11. The image forming apparatus according to claim 10, wherein said coating layer is a resin layer. 12. The resin layer has a thickness of 1 to 200 μm.
The image forming apparatus according to claim 11, wherein 13. An image forming apparatus according to claim 9, wherein said intermediate transfer member has a reinforcing member inside said elastic layer. 14. The image carrier is capable of carrying a plurality of color toner images, and the plurality of color toner images on the image carrier are sequentially superimposed on the intermediate transfer member and transferred. 14. The image forming apparatus according to claim 1, wherein the plurality of color toner images are transferred onto a transfer material. 15. The image forming apparatus includes a plurality of image carriers each carrying a plurality of color toner images, and the plurality of color toner images on the plurality of image carriers are sequentially superimposed on the intermediate transfer member. 14. The image forming apparatus according to claim 1, wherein the transferred toner images of the plurality of colors on the intermediate transfer member are transferred to a transfer material. 16. A rotatable image carrier for carrying a toner image, and a rotatable intermediate transfer body onto which a toner image on the image carrier is transferred at a first transfer position, wherein the intermediate transfer is performed. An image forming apparatus wherein a toner image on a body is transferred to a transfer material at a second transfer position, wherein the intermediate transfer member has at least a polished polishing layer, and the image carrier at the first transfer position And the surface velocities of the intermediate transfer member are different from each other, V1 and V2,
The surface speeds of the intermediate transfer body and the transfer material at the second transfer position are different from each other, and when V3 and V4, V4 <V3 and | V1-V2 | <| V3-V4 | The surface of the intermediate transfer member at the transfer position 2 is:
An image forming apparatus characterized in that the order is in the order of conveyance direction of the transfer material. 17. The image forming apparatus according to claim 16, wherein 0.95 <(V2 / V1) <1.0 and 1.0 <(V3 / V4) <1.05 are satisfied. 18. The image forming apparatus according to claim 16, wherein 0.95 <(V1 / V2) <1.0 and 1.0 <(V3 / V4) <1.05 are satisfied. 19. The image forming apparatus according to claim 1, further comprising a polished polishing layer, and a rotatable first transfer member for transferring the toner image on the image carrier to the intermediate transfer member at the first transfer position. The image forming apparatus according to claim 1, further comprising a transfer unit, wherein the first transfer unit is driven to rotate by the intermediate transfer body, and a polishing edge of the first transfer unit is reverse to a back surface of the intermediate transfer body. Item 18. The image forming apparatus according to any one of Items 16 to 18. 20. The image forming apparatus according to claim 19, wherein said polishing layer is an elastic layer. 21. The image forming apparatus is a second transfer unit that includes at least a polished polishing layer and is capable of abutting on a side of the intermediate transfer body that carries a toner image, wherein the intermediate transfer body A rotatable second transfer unit for transferring the upper toner image onto a transfer material at the second transfer position;
21. The image forming apparatus according to claim 16, wherein the polishing line on the surface of the transfer unit is opposite to the back surface of the transfer material. 22. The image forming apparatus according to claim 21, wherein said polishing layer is an elastic layer. 23. The image forming apparatus, comprising: at least a polished polishing layer; and driving means for rotating and driving the intermediate transfer body in contact with the back surface of the intermediate transfer body. The image forming apparatus according to any one of claims 16 to 22, wherein the image forming apparatus has a reverse face with respect to the back of the body. 24. The image forming apparatus according to claim 16, wherein said polishing layer of said intermediate transfer member is an elastic layer. 25. The image forming apparatus according to claim 24, wherein said intermediate transfer member has a coating layer for coating said elastic layer. 26. The image forming apparatus according to claim 25, wherein said coating layer is a resin layer. 27. The resin layer has a thickness of 1 to 200 μm.
The image forming apparatus according to claim 26, wherein: 28. The intermediate transfer member according to claim 24, further comprising a reinforcing member inside the elastic layer.
Any one of the image forming apparatuses. 29. The image carrier is capable of carrying a plurality of color toner images, and the plurality of color toner images on the image carrier are sequentially superimposed on the intermediate transfer member and transferred. 29. The image forming apparatus according to claim 16, wherein the plurality of color toner images are transferred onto a transfer material. 30. The image forming apparatus includes a plurality of image carriers each carrying a plurality of color toner images, and the plurality of color toner images on the plurality of image carriers are sequentially superimposed on the intermediate transfer member. 29. The image forming apparatus according to claim 16, wherein the plurality of color toner images on the intermediate transfer member are transferred to a transfer material. 31. A rotatable image carrier that carries a toner image, a rotatable intermediate transfer body, and a rotatable intermediate transfer body that abuts on a side of the intermediate transfer body that does not carry the toner image and is rotatable with and driven by the intermediate transfer body. A transfer means for transferring the toner image on the image carrier at a first transfer position, wherein the toner image on the intermediate transfer body is transferred at a second transfer position. In the image forming apparatus that is transferred to a transfer material, the first transfer unit has at least a polished polishing layer, and the polished eyes of the first transfer unit are in a rotation direction of the back surface of the intermediate transfer body. An image forming apparatus characterized in that the image forming apparatus has a reverse order. 32. The image forming apparatus according to claim 31, wherein said polishing layer is an elastic layer. 33. The image forming apparatus according to claim 31, wherein the first transfer unit includes a roller. 34. A rotatable image carrier for carrying a toner image, a rotatable intermediate transfer body onto which a toner image on the image carrier is transferred at a first transfer position, and a toner for the intermediate transfer body Rotatable second transfer means for transferring the toner image on the intermediate transfer member to a transfer material at a second transfer position, the second transfer means being capable of abutting on an image bearing side; In the image forming apparatus, the second transfer means has at least a polished polishing layer, and the polished eyes of the second transfer means are opposite to the rotation direction of the surface of the intermediate transfer body. An image forming apparatus comprising: 35. The image forming apparatus according to claim 34, wherein said polishing layer is an elastic layer. 36. The image forming apparatus according to claim 34, wherein the second transfer unit includes a roller. 37. A rotatable image carrier for carrying a toner image, an intermediate transfer belt on which the toner image on the image carrier is transferred at a first transfer position, and an abutting surface of the intermediate transfer belt. An image forming apparatus that has a driving unit that rotationally drives the intermediate transfer belt, and the toner image on the intermediate transfer belt is transferred to a transfer material at a second transfer position. An image forming apparatus having a polishing layer, wherein a polishing line of the driving unit is reverse to a rotation direction of a back surface of the intermediate transfer belt. 38. The image forming apparatus according to claim 37, wherein the driving unit includes a roller.