JP2000330396A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming device which makes it possible to obtain a stable image for a long time and easily take out each unit from a main body as it is without troubling a user. SOLUTION: In an image forming device which has a photoreceptor drum (first image carrier) 2 for forming a toner image thereon and an intermediate transfer belt (second image carrier) 1 being in contact with the photoreceptor drum 2 during image formation and which transfers the toner image formed on the photoreceptor drum 2 onto the intermediate transfer belt 1, force with which the intermediate transfer belt 1 is abutted on the photoreceptor drum 2 is applied by the driving force of the intermediate transfer belt 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus such as a copying machine or a printer employing an electrophotographic system or an electrostatic recording system.

[0002]

2. Description of the Related Art An intermediate transfer belt is used in a color image forming apparatus such as a color copying machine or a color printer.
The electrostatic latent image formed on the image carrier is visualized as a color toner image by each color developing device, and the visualized color toner images are sequentially superimposed on the intermediate transfer belt and transferred (primary transfer). As a result, a full-color image is formed on an intermediate transfer belt, and the full-color image is collectively transferred (secondarily transferred) to a transfer material.

As shown in FIG. 6, an intermediate transfer belt unit includes an intermediate transfer belt 1, a driving roller 3,
The unit support member 22 is constituted by a secondary transfer roller 6, a secondary transfer opposing roller 4, a tension roller 5 for obtaining the tension of the intermediate transfer belt 1, and the like.
, The intermediate transfer belt unit is positioned with respect to the photosensitive drum 2.

[0004] With the above-described configuration, the intermediate transfer belt 1 absorbs a change in the circumferential length due to a change over time or the like, and is stretched with an appropriate tension for a long period of time.

Incidentally, the primary transfer roller 6 is supported or biased so that a transfer pressure necessary for primary transfer can be obtained with respect to the photosensitive drum 2, whereby a stable primary transfer roller 6 is provided.
Next transfer is guaranteed.

In general, the photosensitive drum 2 and the intermediate transfer belt unit need to be replaced as consumables. To replace these, the swing cam 23 is operated as shown in FIG. Therefore, it is necessary to separate the photosensitive drum 2 and the intermediate transfer belt 1 from each other.

[0007]

However, in the above-described conventional configuration, when the image forming apparatus is in a stopped state, one of the following problems occurs.
In the nip of the next transfer section, the intermediate transfer belt 1 is held while being held between the photosensitive drum 2 and the primary transfer roller 6. Local permanent deformation occurs on the transfer belt 1, the transfer roller 6, and the like, which adversely affects image formation and shortens the life of the unit.

In an image forming apparatus employing a structure in which the photosensitive drum and the intermediate transfer belt unit can be replaced as consumables, when the photosensitive drum and the intermediate transfer belt unit are replaced, they usually come into contact with each other. Unless the photosensitive drum and the intermediate transfer belt are temporarily separated from each other, there is a possibility that the photosensitive layer of the photosensitive drum may be damaged when each unit is taken out from the main body. Therefore, there is a trouble that the operator has to perform an operation (lever operation or the like) for separating the photosensitive drum and the intermediate transfer belt unit at the time of replacement.

As described above, in the conventional configuration, when the image forming apparatus is not performing the image forming operation, the photosensitive drum and the intermediate transfer belt continue to be in contact with each other. This causes deterioration and shortens the life of the intermediate transfer belt.

Furthermore, there is another problem that the unit cannot be easily removed from the main body unless an operator performs an operation of separating the photosensitive drum and the intermediate transfer belt unit when replacing the photosensitive drum and the intermediate transfer belt unit.

However, the above problems shorten the life of the unit and complicate the product due to the necessity of the separating mechanism.
This caused the total cost of the product to rise.

Although the above has been described with reference to an example of a color image forming apparatus using an intermediate transfer belt, a similar problem also occurs in an image forming apparatus using an intermediate transfer drum. A similar problem occurs in an image forming apparatus using a transfer belt (transport belt) or a transfer roller instead of the intermediate transfer member. Further, the same problem occurs in a monochrome image forming apparatus in which the transfer roller is directly in contact with the photosensitive drum and the photosensitive drum and the transfer roller need to be separated for unit replacement or jam processing.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and an object thereof is to provide a stable image for a long period of time and to allow each unit to be easily detached from the main body without bothering the user. An object of the present invention is to provide an image forming apparatus that can be taken out of the apparatus.

[0014]

To achieve the above object, according to the first aspect of the present invention, there is provided a method for forming a first image on which a toner image is formed.
And a second image carrier that comes into contact with the first image carrier during image formation. The toner image formed on the first image carrier is transferred to the second image carrier. In the image forming apparatus for transferring images onto a carrier, a driving force of the second image carrier applies a force for bringing the second image carrier into contact with the first image carrier. .

According to a second aspect of the present invention, in the first aspect of the present invention, the first image carrier is a drum-shaped rotating body.

According to a third aspect of the present invention, in the second aspect, the second image bearing member is a drum-shaped rotating member.

According to a fourth aspect of the present invention, in the second aspect, the second image bearing member is a belt-shaped rotating member.

According to a fifth aspect of the present invention, in the first aspect of the present invention, the first image bearing member is a belt-shaped rotating member.

According to a sixth aspect of the present invention, in the fifth aspect, the second image carrier is a drum-shaped rotating body.

According to a seventh aspect of the present invention, in the fifth aspect of the invention, the second image carrier is a belt-shaped rotating body.

The invention according to claim 8 has a first image carrier on which a toner image is formed, and a second image carrier which comes into contact with the first image carrier during image formation. In an image forming apparatus for transferring a toner image formed on a first image carrier onto the second image carrier, the first image carrier is moved by the driving force of the first image carrier. It is characterized in that a force for contacting the second image carrier is applied.

According to a ninth aspect of the present invention, in the eighth aspect of the present invention, the first image bearing member is a belt-shaped rotating member.

According to a tenth aspect, in the ninth aspect, the second image carrier is a drum-shaped rotating body.

According to an eleventh aspect of the present invention, in the ninth aspect, the second image bearing member is a belt-shaped rotating member.

[0025]

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

<Embodiment 1> FIG. 1 is a structural view of an intermediate transfer belt unit of a color image forming apparatus according to the present invention. As shown in FIG.
A primary transfer roller 6 supported by a swing arm 8 is provided on a side opposite to the photosensitive drum 2 with the intermediate transfer belt 1 interposed therebetween. I have.

The driving roller 3 of the intermediate transfer belt 1
Is driven, a driving force is transmitted from a gear (not shown) fixedly supported coaxially with the driving roller 3 to the swing gear 11 via the A gear train 10. Here, the swing gear 1
1 is rotatably supported by the last gear (oscillating gear) 10 a of the A gear train 10, so that it rotates by the driving force transmitted from the A gear train 10 and rotates the B gear train 12. The driving force is transmitted by meshing with the first stage gear 12a.

The rotational force of the B gear train 12 to which the driving force is transmitted from the swing gear 11 is applied to the final gear 12b.
The tension adjusting cam 9 is pressurized by a constant force that overcomes the reaction force of the tension spring 13 via a torque limiter (not shown) installed on the same axis as the above, and the tension roller 5 is moved in a direction to obtain the tension.

Accordingly, the swing arm 8 swings with the movement of the shaft 5a of the tension roller 5 with the shaft 3a of the drive roller 3 as a fulcrum, and is supported by the swing arm 8 (or the photosensitive drum by a spring or the like). The primary transfer roller 6 urged to 2) moves in conjunction with the movement of the tension roller 5.

When the intermediate transfer belt 1 is driven to rotate, an appropriate tension is always obtained on the intermediate transfer belt 1 and at the same time, the primary transfer roller 6 is attached to the photosensitive drum 2 by the intermediate transfer belt. 1 is abutted.

FIG. 2 shows a state in which the intermediate transfer belt 1 shown in FIG. 1 is not driven. In this state, since the A gear train 10 is not driven, the swing gear 11 is not driven. It falls by its own weight and separates from the B gear train 12. Therefore, the B gear train 12 is free to rotate, and the tension roller 5 and the tension adjusting cam 9 move in the direction of releasing the belt tension by the urging force of the tension spring 13. At this time, the swing arm 8 moves together with the primary transfer roller 6 in accordance with the movement of the tension roller 5, and the intermediate transfer belt 1 is separated from the photosensitive drum 2 as shown in the figure.

As described above, in the present embodiment, when the intermediate transfer belt 1 is driven to rotate,
The intermediate transfer belt 1 is tensioned with an appropriate tension and contacts the photosensitive drum 2, but once the intermediate transfer belt 1 is in a non-driving state, the tension of the intermediate transfer belt 1 is automatically released, and the intermediate transfer belt 1 is released. 1 is separated from the photosensitive drum 2, unnecessary force that deteriorates the intermediate transfer belt 1 is removed, and the life of the intermediate transfer belt 1 is extended.

That is, when the intermediate transfer belt 1 is not driven, the tension of the intermediate transfer belt 1 is released,
A state in which the intermediate transfer belt 1 is separated from the photosensitive drum 2 is realized. In this state, the user can easily take out the consumables such as the intermediate transfer belt 1 and the photosensitive drum 2 from the main body without any special operation and remove them. Can be exchanged for a new one.

In the present embodiment, an embodiment in which the present invention is applied to an image forming apparatus using a photosensitive drum as the first image carrier and an intermediate transfer belt as the second image carrier has been described. Is similarly applicable to an image forming apparatus using a belt photoreceptor or an intermediate transfer member as a first image carrier and a transport belt or a transfer belt as a second image carrier.

Second Embodiment Next, a second embodiment of the present invention will be described with reference to FIG.

FIG. 3 is a structural view of a main part of a color image forming apparatus using an intermediate transfer drum as an intermediate transfer member.
(A) shows the driving state of the intermediate transfer drum, and (b) shows the non-driving state of the intermediate transfer drum.

In the driving state of the intermediate transfer drum 14 shown in FIG. 3A, the rotation of the driving gear 17 driven by the driving motor 7 to rotate in the direction shown by the arrow (clockwise) is transmitted to the driven gear 18 and The driven gear 18 and the intermediate transfer drum 14 are driven to rotate in the direction shown by the arrow (counterclockwise).

The driven gear 18 and the intermediate transfer belt 14 are rotatably supported by a rotating shaft 16 at an intermediate portion of a swing arm 20, and one end of the swing arm 20 is supported by the rotating shaft 15 of the driving gear 17. Have been.

Accordingly, as described above, the intermediate transfer drum 14
Is driven in the direction of the arrow (counterclockwise) in the figure, the intermediate transfer drum 14 rotates in the direction of the arrow (clockwise) about the rotating shaft 15 and contacts the photosensitive drum 2. At this time, the inter-axis compensating member 19 provided on the main body side comes into contact with the other end of the swing arm 20 so that the intermediate transfer drum 1
The intermediate distance between the shaft 4 and the photosensitive drum 2 is regulated, and the intermediate transfer drum 14 contacts the photosensitive drum 2 at a desired contact pressure.

On the other hand, when the drive motor 7 stops, FIG.
In this state, the intermediate transfer drum 14 is separated from the photosensitive drum 2 by its own weight. In this state, the intermediate transfer drum 14 and the photosensitive drum 2 are easily taken out of the main body and replaced with new ones. can do.

When an elastic layer is formed on the surface of the intermediate transfer drum 14, the intermediate transfer drum 14 is separated from the photosensitive drum 2 when it is not driven, so that the elastic layer is permanently deformed at the primary transfer position. Can be prevented, a stable image can be obtained for a long period of time, and the life of the intermediate transfer drum 14 can be extended.

In this embodiment, the embodiment in which the present invention is applied to a color image forming apparatus using a photosensitive drum as the first image carrier and an intermediate transfer drum as the second image carrier has been described. The invention relates to a belt photoreceptor and an intermediate transfer member as a first image carrier, a transfer drum as a second image carrier,
The present invention is similarly applicable to an image forming apparatus using a transfer roller, a transport roller, and the like.

Third Embodiment Next, a third embodiment of the present invention will be described with reference to FIGS. 4 and 5 are block diagrams of the intermediate transfer belt unit of the color image forming apparatus according to the present embodiment. In these figures, the same elements as those shown in FIGS. In the following, description thereof will be omitted.

In this embodiment, the belt photoconductor 2
4, the belt photoreceptor 21 is moved by the urging force of the primary transfer roller 6 to move the intermediate transfer drum 14 as shown in FIG.
Is in contact with

On the other hand, when the belt photoconductor 21 is not driven,
As shown in FIG. 5, the swing gear 11 is disengaged from the B gear train 12, and the tension roller 5 moves in a direction for separating the belt photoconductor 21 from the intermediate transfer drum 14 by the urging force of the tension spring 13.

Thus, also in this embodiment, when the belt photosensitive member 21 is not driven, the belt photosensitive member 2
1 is separated from the intermediate transfer belt 14, so that the same effects as those of the first and second embodiments can be obtained.

In the present embodiment, an embodiment in which the present invention is applied to a color image forming apparatus using a belt photoreceptor as a first image carrier and an intermediate transfer drum as a second image carrier has been described. The present invention is similarly applicable to an image forming apparatus using a transport belt or a transfer belt as the second image carrier.

[0048]

As is apparent from the above description, according to the present invention, the first image carrier on which the toner image is formed and the second image carrier which comes into contact with the first image carrier during image formation. An image forming apparatus having an image bearing member for transferring a toner image formed on the first image bearing member onto the second image bearing member. The second image carrier (first image carrier) is driven by the driving force of the image carrier.
A force for contacting the image carrier (second image carrier) is provided, so that a stable image can be obtained for a long period of time, and each unit can be directly moved from the main body without bothering the user. The effect that it can be easily taken out is obtained.

[Brief description of the drawings]

FIG. 1 illustrates an intermediate transfer belt unit (when an intermediate transfer belt is driven) of a color image forming apparatus according to a first embodiment of the present invention.
FIG.

FIG. 2 is a configuration diagram of an intermediate transfer belt unit (when the intermediate transfer belt is not driven) of the color image forming apparatus according to the first embodiment of the present invention.

FIG. 3 is a configuration diagram of an intermediate transfer drum part of a color image forming apparatus according to Embodiment 2 of the present invention.

FIG. 4 is a configuration diagram (when a belt photoconductor is driven) of an intermediate transfer belt unit of a color image forming apparatus according to Embodiment 3 of the present invention.

FIG. 5 is a configuration diagram of the intermediate transfer belt unit of the color image forming apparatus according to Embodiment 3 of the present invention (when the belt photoconductor is not driven).

FIG. 6 is a configuration diagram of an intermediate transfer belt unit of the conventional color image forming apparatus (when the intermediate transfer belt is driven).

FIG. 7 is a configuration diagram of the intermediate transfer belt unit of the conventional color image forming apparatus (when the intermediate transfer belt is not driven).

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 intermediate transfer belt (second image carrier) 2 photosensitive drum (first image carrier) 3 drive roller 4 secondary transfer opposing roller 5 tension roller 6 primary transfer roller 7 drive motor 8 swing arm 9 tension adjustment Cam 10 A gear train 11 Oscillating gear 12 B gear train 14 Intermediate transfer drum (second image carrier) 21 Belt photoconductor (first image carrier)

Claims (11)

[Claims] A first image bearing member on which a toner image is formed; and a second image bearing member which comes into contact with the first image bearing member during image formation, wherein the first image bearing member is provided. An image forming apparatus for transferring a toner image formed thereon onto the second image carrier, wherein the second image carrier is driven by the driving force of the second image carrier. An image forming apparatus for applying a force to abut against the image forming apparatus. 2. The image forming apparatus according to claim 1, wherein said first image bearing member is a drum-shaped rotating member. 3. The image forming apparatus according to claim 2, wherein said second image carrier is a drum-shaped rotating body. 4. An image forming apparatus according to claim 2, wherein said second image carrier is a belt-shaped rotating body. 5. The image forming apparatus according to claim 1, wherein said first image bearing member is a belt-shaped rotating member. 6. An image forming apparatus according to claim 5, wherein said second image carrier is a drum-shaped rotating body. 7. An image forming apparatus according to claim 5, wherein said second image carrier is a belt-shaped rotating body. 8. A first image carrier having a first image carrier on which a toner image is formed, and a second image carrier which comes into contact with the first image carrier during image formation. An image forming apparatus for transferring a toner image formed thereon onto the second image carrier, wherein the first image carrier is moved by the driving force of the first image carrier. An image forming apparatus for applying a force to abut against the image forming apparatus. 9. An image forming apparatus according to claim 8, wherein said first image carrier is a belt-shaped rotating body. 10. An image forming apparatus according to claim 9, wherein said second image carrier is a drum-shaped rotating body. 11. An image forming apparatus according to claim 9, wherein said second image bearing member is a belt-shaped rotating member.