JP3298703B2 - Image forming device - Google Patents

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 intermediate image carrier such as an intermediate transfer belt in addition to an image carrier such as a photosensitive member.

[0002]

2. Description of the Related Art In an image forming apparatus such as a copying machine, a printer or a facsimile, a toner image is formed on the surface of an image carrier such as a photoreceptor, and the toner image is formed on an intermediate image carrier such as an intermediate transfer belt. There is known an image forming apparatus which transfers and further transfers a toner image transferred onto the intermediate image carrier to a transfer material. A typical example is a color image forming apparatus. In this image forming apparatus, toner images of different colors are respectively formed on an image carrier, and each toner image is superimposed and transferred to the same position on an intermediate image carrier, and the superimposed toner image is transferred onto a transfer material. Thus, a predetermined color image is obtained on the transfer material.

[0003] In an image forming apparatus using such an intermediate image transfer material, the image carrier, the intermediate image carrier, and the transfer material are not skillfully selected from the viewpoint of friction coefficient. In this case, transfer failure is likely to occur.

For example, when a toner image is transferred from a surface having a small coefficient of friction to a surface having a large friction coefficient, transferability is not impaired. However, in the opposite case, transfer failure is liable to occur. There is a possibility that a character portion dropout phenomenon called "biting" may occur.

[0005]

SUMMARY OF THE INVENTION It is an object of the present invention to reduce the occurrence of transfer defects such as a missing character portion.
It is an object of the present invention to provide an image forming apparatus capable of further improving image quality.

[0006]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides an image carrier on which a toner image is formed on a surface by being driven to rotate, and an image carrier which is driven to rotate while being in contact with the image carrier. An image forming apparatus comprising: an intermediate image carrier on which the toner image is transferred to the surface, and configured to transfer the toner image on the intermediate image carrier to a transfer material.
The relative coefficient of friction between the contacted body and the contacted body that comes into frictional contact with it is α, the relative friction coefficient between the intermediate image carrier and the same as the contacted body is β, the transfer material, and the contacted body. Assuming that the relative friction coefficient between the same is γ, the image carrier, the intermediate image carrier, and the transfer material are in a surface state such that the magnitude relationship of the friction coefficients is α ≦ β ≦ γ. By applying a lubricating oil additive to at least one of the image bearing member and the intermediate image bearing member by a lubricating oil additive applying means, a magnitude relationship between friction coefficients is established, and the lubricating oil additive applying means is applied. Is a carrier for both the image carrier and the intermediate image carrier,
An image forming apparatus characterized by being displaceable so that a lubricant additive can be applied.

In order to achieve the above object, the present invention also provides an image carrier on which a toner image is formed on the surface by rotating the image carrier, and a rotational drive while being in contact with the image carrier. And an intermediate image carrier transferred to the surface,
In an image forming apparatus configured to transfer a toner image on the intermediate image carrier to a transfer material, the relative friction coefficient between the image carrier and a contacted member that comes into frictional contact with the image carrier is α, Body, the relative friction coefficient between the same as the contacted body is β, the transfer material, and the relative friction coefficient between the same as the contacted body as γ, the image carrier, The intermediate image carrier and the transfer material, the magnitude relationship of the coefficient of friction is α ≦ β ≦
By applying a lubricating oil additive to at least one of the image bearing member and the intermediate image bearing member by a lubricant additive applying means, a surface condition such as γ is established, thereby establishing a magnitude relationship between friction coefficients. The lubricating oil additive applying means is configured to apply the lubricating oil additive by contacting only one of the image carrier and the intermediate image carrier; The present invention proposes an image forming apparatus characterized in that it is driven to rotate so as to generate a speed difference during the application.

[0008]

[0009]

[0010]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 shows a schematic configuration of an image forming apparatus according to an embodiment of the present invention. The image forming apparatus in this figure is of a color type, and includes a color image reading apparatus 1,
It mainly comprises a color image recording device 2.

In the main body of the color image recording apparatus 2, there is provided a drum-shaped photoreceptor 3, which is an example of the configuration of an image carrier, and the photoreceptor 3 is rotated in a counterclockwise direction in FIG. It is designed to be driven. During this rotation, the surface of the photoconductor 3 is uniformly charged by the charging charger 4.

Next, in the exposure unit 5, a predetermined electrostatic latent image is formed on the surface of the photosensitive member 3 by performing optical writing scanning using the writing optical unit 6. The developing device 7 includes developing devices 7B, 7C, 7M, and 7Y that perform development with toners of different colors, respectively, and the electrostatic latent image can be used as a toner image with any one of the developing devices. It is visualized. Thus, the photoconductor 3 is driven to rotate, and a toner image is formed on the surface thereof.

The intermediate transfer belt 8 is an example of a configuration of an intermediate image carrier that can be called an intermediate image carrier, and is rotated in a clockwise direction in FIG. It has become. That is, the intermediate transfer belt 8 is driven to rotate so that the belt portion in contact with the photoconductor 3 moves in the same direction as the direction of movement of the surface of the photoconductor 3 that is in contact with the belt.

The toner image formed on the photoconductor 3 is electrostatically transferred to the surface of the intermediate transfer belt 8 at a portion of the intermediate transfer belt 8 that contacts the photoconductor 3. This transfer is referred to as a first transfer unit, and a toner image of another color is sequentially formed on the photoreceptor 3 for each rotation thereof, and the toner image is transferred to the first transfer unit 11. At the same time, the image is superimposed and transferred to the same position on the intermediate transfer belt 8. Thus, a color toner image is formed on the intermediate transfer belt 8.

On the other hand, a transfer material 9 made of plain paper or the like is fed from a transfer material feed unit 10, and the color toner image on the intermediate transfer belt 8 is electrostatically transferred onto the transfer material 9 in the transfer unit 12. Is transcribed. In this way, the transfer unit 12
Is also referred to as a second transfer section for the transfer section.

The transfer material 9 to which the color toner image has been transferred is
Thereafter, the sheet is sent to the fixing device 14 by the transport belt 13, and is discharged to the tray 15 through this device.

After the toner image on the photoreceptor 3 is transferred to the intermediate transfer belt 8 in the first transfer section 11, the surface of the photoreceptor is cleaned by a photoreceptor cleaning device 16, and then a static eliminator (not shown) Is removed. After the second transfer, the belt cleaning device 17
1 (not shown in FIG. 1, see FIG. 2), the surface of the intermediate transfer belt 8 is cleaned.

Here, in the image forming apparatus using the intermediate transfer belt, the photosensitive member 3, the intermediate transfer belt 8, the transfer material 9
For each of the above cases, poor transfer is likely to occur unless a material selection is made skillfully from the viewpoint of the coefficient of friction.

For example, as described above, when a toner image is transferred from a surface having a small coefficient of friction to a surface having a large coefficient of friction, transferability is not impaired. This may cause a so-called “insect bite” to cause a character portion dropout phenomenon.

The features of the embodiment of the present invention are as follows.
Concerning the coefficient of friction, the photosensitive member 3 and the contacted object that comes into frictional contact with the photosensitive member 3 (the contact object assumed when discussing the coefficient of friction)
Is the relative friction coefficient between the intermediate transfer belt 8 and the same member as the contacted member, and β is the relative friction coefficient between the intermediate transfer belt 8 and the same member as the contacted member. Assuming that the friction coefficient is γ, the photosensitive member 3 and the intermediate transfer belt 8
And the transfer material 9 is in such a surface state that the magnitude relationship of the friction coefficients is α ≦ β ≦ γ.

For example, for the three members, materials having such a magnitude relationship may be selected.

Here, as a material of the photoreceptor 3, amorphous silicon, organic photoconductor (OPC), selenium and the like are selected as typical examples. The intermediate transfer belt 8 may be made of, for example, an electric resistance such as an elastic rubber or a polycarbonate resin in order to make it easy to hold the electric charge from the top of the transfer or to make it possible to perform the self-discharge without the charge eliminator. Is a medium resistance (about 1 × 10 ⁸ Ωcm).

The friction coefficient of the photoreceptor is as follows when classified by type. The friction coefficient is a coefficient when the same contacted object is used as a partner. (1) A-Si (amorphous silicon) around 0.7 (2) Overcoat selenium drum 0.8-0.9 (3) OPC (organic photoconductor) 1.0-1.2 (4) Selenium Drum 1.2-1.4

Further, the friction coefficient of the intermediate transfer belt can be classified as follows. (1) An elastic rubber surface provided with a coating layer such as Teflon 0.6 to 1.0 (2) Polycarbonate 1.0 to 1.4

Considering the friction coefficient of the transfer material 9 itself, the materials of the other two members (photoreceptor and intermediate transfer belt) are changed so that the magnitude relation of the friction coefficient described above satisfies α ≦ β ≦ γ. If various selections are made, it is possible to suppress the occurrence of a transfer failure such as a blank portion in a character portion, and to further improve the image quality.

By selecting various materials, the photoreceptor, the intermediate transfer belt, the transfer material, and the like can be brought into a surface state having the above-mentioned frictional coefficient magnitude relationship. In some cases, it is not possible to select a material that can be successfully established.

For example, in some cases, it is necessary to select a material such that α> β due to various constraints instead of α <β. In such a case, for example, a lubricating oil additive is applied to the photoreceptor 3 by a lubricating oil additive applying unit, and the friction coefficient is reduced so that α <β. In this case, even if the application condition is such that α = β, it is more advantageous than the case where no application is performed.

In FIG. 1, reference numeral 19 denotes a lubricating oil additive application device which is an example of a configuration of a lubricating oil additive applying means. FIG. 2 shows the lubricating oil additive application device 19 in an enlarged manner.

Here, the lubricating oil additives include zinc stearate, iron stearate, barium stearate, nickel stearate, cobalt stearate, copper stearate, strontium stearate, calcium stearate, cadmium stearate, and stearic acid. Magnesium, cobalt oleate, zinc oleate, manganese oleate, iron oleate, zinc palmitate, cobalt palmitate, copper palmitate, magnesium palmitate, aluminum palmitate, calcium palmitate, lead caprylate, copper caprylate, Metal salts of fatty acids such as zinc linolenate, cobalt linolenate, calcium linolenate, candelilla wax, carnauba wax, rice wax, wood wax, joba oil, beeswax, lanolin Such as wax and the like.

In FIG. 2, what is indicated by reference numeral 20 is a solidified product of such a lubricant additive.

The rocking member 22 to which the solid lubricating oil additive 20 and the application brush 21 brought into contact with the solid lubricating oil additive 20 are pivotally attached to the device substrate 24 by the pins 23. It is held at a position where it is stopped by the stopper pin 25.

A solenoid 26 is connected to the swing member 22. When the solenoid 26 is excited, the swing member 22
3, the application brush 21 comes into contact with the intermediate transfer belt 8. In this state, the application brush 21
It is driven to rotate so as to rub against the intermediate transfer belt 8.

During this rotation, the lubricant additive is supplied from the solid lubricant additive 20 to the application brush 21 and applied thereto.
The lubricating oil additive applied to the application brush 21 is uniformly applied to the intermediate transfer belt 8. That is, a thin film of the lubricating oil additive is formed on the surface of the intermediate transfer belt 8. The photoconductor 3 and the intermediate transfer belt 8 are, for example,
When the intermediate transfer belt 8 is made of a material that satisfies the relationship α> β, the intermediate transfer belt 8 is coated with a lubricant additive such that α ≦ β, so that the photosensitive member 3 and the intermediate transfer belt 8 Means that the surface state satisfies α ≦ β. In this case, of course, the relationship of the friction coefficient with the transfer material is also considered.

The transfer material 9 is used for such application.
Is performed until the next transfer material arrives at the transfer section after passing through the second transfer section 12, or at the end of copying.

To the photoconductor 3, a lubricating oil additive application device having a similar configuration is provided so that the same or different lubricating oil additives are applied to the photoconductor 3, or the photoconductor 3 and the intermediate transfer belt are applied. 8, the same or different lubricating oil additives can be applied.

As described above, the photosensitive member 3 and the intermediate transfer belt 8
The lubricating oil additive can be applied to at least one of the two by the lubricating oil additive applying means, and the magnitude relationship between the friction coefficients can be established as described above.

Further, the means for applying a lubricating oil additive is
And the intermediate transfer belt 8 is contacted to apply the lubricating oil additive to the photosensitive member 3 and the intermediate transfer belt 8 during the application. For example, when the lubricant is applied to the intermediate transfer belt 8 and the lubricant additive on the surface thereof is transferred to the photoreceptor 3 in the first transfer unit 11, the intermediate transfer belt 8 The same type of lubricant additive can be applied to both the photoreceptor 3 and the intermediate transfer belt 8 only by the lubricant additive application device 19 attached to
Only one lubricating oil additive application device is required. The same applies to the case where a lubricant additive is applied to the photoconductor 3.

With this configuration, the number of parts is reduced, the cost can be reduced, and the maintenance is simplified.

In order to make the linear velocity between the photosensitive member 3 and the intermediate transfer belt 8 different, for example,
The speed is made faster or slower than the linear speed of the photoconductor 3. In the present embodiment, the intermediate transfer belt 8 is stretched between the driving roller 27 and the driven rollers 28, 28, and the driving speed of the driving roller 27 is reduced when the lubricant additive is applied.
You just have to change it. On the other hand, the rotation direction of the intermediate transfer belt 8 may be reversed. Of course, the intermediate transfer belt 8 may be left as it is, and the linear velocity and the rotation direction of the photoconductor 3 may be changed.

In the embodiment shown in FIG. 3, a lubricating oil additive application device 29, which is an example of a configuration of a lubricating oil additive applying means, is used to apply lubricating oil to both the photoconductor 3 and the intermediate transfer belt 8. It is configured to be displaceable so that the agent can be applied.

The solid lubricant additive 20 and the application brush 31
The swing member 32 to which the components are attached is pivotally attached to the device substrate 24 by pins 33, and is swingably driven by a driving means such as a solenoid. That is, the application brush 31 can be brought into contact with both the photoconductor 3 and the intermediate transfer belt 8.

When applying the lubricating oil additive only to the photoconductor 3, the application brush 31 is brought into contact with the photoconductor 3.
When the lubricant additive is applied only to the intermediate transfer belt 8, the application brush 31 is brought into contact with the intermediate transfer belt 8. On the other hand, when applying the lubricating oil additive to both, the contact position may be switched as appropriate.

In any case, the lubricating oil additive application device 29 in this embodiment is displaceable so that the lubricating oil additive can be applied to both the photoreceptor 3 and the intermediate transfer belt 8. It is, of the photoconductor and the intermediate transfer belt,
A lubricating oil additive can be applied to a desired image carrier. Thereby, since only one lubricating oil additive application device is required, the configuration of the application means is simplified, the number of parts is reduced, and
It is also advantageous in terms of cost. And, for maintenance, it is sufficient to perform only one lubricating oil additive application device,
Serviceability is also improved.

Of course, the application brush 31 shown in FIG. 3 may be configured to be simultaneously contacted with the photoreceptor 3 and the intermediate transfer belt 8 so that the lubricant additive can be applied to both of them at the same time.

The present invention can be widely applied to an image forming apparatus and the like in which the image carrier is constituted by a belt and the intermediate image carrier is constituted by a drum or the like.

[0047]

According to the present invention, when performing a stepwise transfer of a toner image from an image bearing member to a transfer material via an intermediate image bearing member, the occurrence of transfer defects such as missing characters can be suppressed. The image quality can be further improved. Moreover, the magnitude relationship between the friction coefficients of the three members can be established without being restricted by the selection of the material type such as the image carrier, the intermediate image carrier, and the transfer material. Furthermore, since only one means for applying the lubricant additive is required, the application configuration is simplified, the number of parts is reduced, and the cost and space are advantageous. In addition, maintenance and the like are simplified.

[0048]

[0049]

[Brief description of the drawings]

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

FIG. 2 is an enlarged view of a main part of the image forming apparatus.

FIG. 3 is a diagram showing an example in which a oscillating lubricating oil additive coating device is interposed between a photoreceptor and an intermediate transfer belt.

[Explanation of symbols]

 9 Transfer material 19 Lubricating oil additive application device 29 Lubricating oil additive application device

Claims (2)

(57) [Claims] An image carrier on which a toner image is formed on a surface thereof which is rotationally driven; and an intermediate image carrier which is rotationally driven while being in contact with the image carrier and a toner image on the image carrier is transferred onto the surface. And an image forming apparatus configured to transfer the toner image on the intermediate image carrier to a transfer material, wherein a relative friction coefficient between the image carrier and a contacted member frictionally contacting the image carrier is α. , The relative friction coefficient between the intermediate image carrier and the same member as the contacted member is β, and the relative friction coefficient between the transfer material and the same member as the contacted member is γ, The carrier, the intermediate image carrier, and the transfer material, in a surface state such that the magnitude relationship of the friction coefficient is α ≦ β ≦ γ, and at least one of the image carrier and the intermediate image carrier, By applying the lubricating oil additive with the lubricating oil additive applying means, the magnitude relationship of the friction coefficient is established. The lubricant additive applying means is displaceable so that the lubricant additive can be applied to both the image carrier and the intermediate image carrier. Image forming apparatus. 2. An image carrier having a toner image formed on a surface thereof which is rotationally driven, and an intermediate image carrier which is rotationally driven while being in contact with the image carrier and a toner image on the image carrier is transferred onto the surface. And an image forming apparatus configured to transfer the toner image on the intermediate image carrier to a transfer material, wherein a relative friction coefficient between the image carrier and a contacted member frictionally contacting the image carrier is α. , The relative friction coefficient between the intermediate image carrier and the same member as the contacted member is β, and the relative friction coefficient between the transfer material and the same member as the contacted member is γ, The carrier, the intermediate image carrier, and the transfer material, in a surface state such that the magnitude relationship of the friction coefficient is α ≦ β ≦ γ, and at least one of the image carrier and the intermediate image carrier, By applying the lubricating oil additive with the lubricating oil additive applying means, the magnitude relationship of the friction coefficient is established. The lubricating oil additive applying means is adapted to apply the lubricating oil additive by contacting only one of the image bearing member and the intermediate image bearing member. The image forming apparatus is characterized in that the body is rotatably driven to generate a speed difference at the time of application.