JPH0519640A - Color image forming device - Google Patents

Abstract

PURPOSE:To prevent jamming from occurring by providing a transfer material separating and conducting member for changing the direction of a transfer material lest the transfer material should go toward a transfer part when the transfer paper is doubly fed. CONSTITUTION:The transfer material separating and conducting member 12 is provided, which separates the transfer paper P2, which does not reach a clamping position as compared with a transfer paper P1 on a side in contact with a transfer drum 2, and changes the direction of the transfer paper P2 to an opposite direction to the transfer part 7 lest it should go toward the transfer part 7 after the leading edge side of the transfer paper P2 passes through a clamping member 3 when the transfer papers, two papers in all, are previously fed from the transfer part. A brush roller 12 is provided to contact with the transfer drum 2 between a resist roller pair 6 and the transfer part 7. In such a case, the brush roller 12 is driven to be rotated so that it may rub and move in a direction opposite to the moving direction of the surface of the drum 2 at a part where the outer peripheral part contacts with the surface of the drum 2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a color image forming apparatus having a transfer drum.

[0002]

2. Description of the Related Art As a color image forming apparatus having a transfer drum, those disclosed in Japanese Patent Laid-Open Nos. 60-168168 and 64-13562 have been already proposed. Generally, in this type of image forming apparatus, a clamp member is provided on the transfer drum, and while the front end of the fed transfer material is clamped by the clamp member, the transfer material is wound around the outer peripheral surface of the transfer drum. There is.

As a transfer material, a transfer paper made of plain paper is usually used well. However, when the transfer paper is fed from a predetermined paper feeding portion, a plurality of transfer papers are fed while being overlapped. Sometimes. For example, in the case of the upper feeding type paper feeding device, not only the uppermost transfer paper but also the second and subsequent transfer papers are fed at the same time.

For example, assuming that two sheets of transfer paper are fed at the same time, there is no problem if the leading edges of both are aligned and clamped by the clamp member. If the uppermost transfer paper is fed toward the clamp member with the transfer paper retracted by a predetermined distance, the leading end of the uppermost transfer paper is clamped by the clamp member, but the leading end of the next transfer paper is reached. However, the transfer direction is not fixed, and the transfer paper is apt to jam. Two
The same applies when a sheet of transfer paper is fed with its leading edge aligned and only the uppermost transfer paper is clamped by the clamp member.

This point will be described more specifically using the color image forming apparatus of the example shown in FIG.
Reference numeral 1 denotes a drum-shaped photoconductor that is an example of a latent image carrier, and the photoconductor 1 is rotationally driven in the clockwise direction, and a color image having different colors is formed on the surface of the photoconductor at each rotation.
To be formed. The transfer drum 2 is arranged so as to face the photoconductor 1, and a clamp member 3 is provided on the transfer drum 2 so as to be openable and closable. The position indicated by the broken line is the open position.

The transfer paper 5 is sent from the paper feed unit 4 toward the transfer drum 2 through the pair of registration rollers 6. At this time, the transfer paper 5 is transferred into the clamp member 3 which is opened at a proper timing. The leading edge of the paper enters and strikes against the back of the clamp member. After that, the clamp member 3 is closed, so that the front end of the clamp member 3 is clamped on the transfer drum 2. In this clamped state, the transfer paper is wound around the outer peripheral surface of the transfer drum 2.

On the other hand, a color image of a different color is formed on the photoconductor 1 each time the photoconductor 1 makes one revolution, and the first color image is formed at the first revolution of the photoconductor 1 and the transfer drum 2. However, in the transfer section 7 where the photoconductor 1 and the transfer drum 2 face each other, the transfer paper wound around the transfer drum 2 contacts the photoconductor 1 and is transferred to the transfer paper. Next, at the second rotation, the next color image is transferred and transferred to the same position on the transfer paper. After that, in the same manner, a color image of another color is superposed and transferred onto the transfer paper, and when the superposing transfer is completed, the clamp member 3 is opened and the tip portion thereof is separated by the separation claw 8.
And the transfer paper is removed from the transfer drum 2,
It is sent on the conveyor belt 9 and advances to a fixing device (not shown).

As described above, the transfer paper is fed from the paper feed section 4, but at this time, a plurality of transfer papers,
It may be fed while overlapping. For example, as shown in the figure, in the case of the upward feeding method, not only the uppermost transfer paper but also the next and subsequent transfer papers are simultaneously sent.

For example, if two transfer sheets are fed at the same time, there is no problem if the leading edges of the two are aligned and clamped by the clamp member 3, but for the uppermost transfer sheet, If the next-order transfer paper is fed toward the clamp member 3 while retracted by a predetermined distance, the leading end of the highest-order transfer paper is clamped by the clamp member 3, but the next-order transfer paper is transferred. The leading edge of the paper may not be clamped. Even when the two transfer sheets are fed with their leading edges aligned, only the uppermost transfer sheet may be clamped by the clamp member 3. With respect to such a transfer paper that is not clamped, the traveling direction is not determined, the cleaning paper 1 passes through the transfer unit 7, and is located on the outlet side of the transfer unit 7 with respect to the clamp-side portion of the transfer paper.
There is a case that even 1 goes in. The cleaning device 11 cleans the surface of the photoconductor 1 after the color image is transferred onto the transfer paper.

With respect to such a transfer sheet having a clamp error, it is inevitable that a jam will occur in the main body of the image forming apparatus. Incidentally, in FIG. 8, the reference numeral P ₁ is the uppermost transfer paper, which is properly clamped, and is removed from the transfer drum 2 after the final transfer and is not shown in the figure. Head to the device. On the other hand, the reference numeral P ₂ is the next transfer sheet in which the clamping error has occurred, and the jam has occurred from the cleaning device 11 across the registration roller pair 6.

In most cases, the transfer paper with the jam is left at a place where the user can process it. However, when the transfer paper is jammed at the above-mentioned place, the transfer paper is Since it is difficult to install the jam detection sensor in such a place, it is impossible to stop the machine immediately,
As shown in the figure, the transfer paper may enter the magnet brush roller 13 in the cleaning device 11 and the vicinity of the bias roller 14 as well, which causes the collected developer to overflow into the cleaning device. In such a case, the user can not handle it,
It will be handled by a professional service person.

[0012]

SUMMARY OF THE INVENTION It is an object of the present invention to, when a transfer material is double-fed, guide the transfer material having a clamping error so that it will not be directed to the transfer area, and transfer it. It is an object of the present invention to provide a color image forming apparatus capable of preventing the occurrence of a jam with the process equipment on the exit side of the device.

[0013]

In order to achieve the above object, the present invention is directed to a latent image carrier on which color visible images of different colors are sequentially formed, and a transfer material disposed so as to face the latent image carrier. A latent image carrier and a transfer drum, and a transfer drum for winding the sheet around the peripheral surface, and a clamp member provided on the transfer drum for clamping the front end of the fed transfer material on the transfer drum. In the transfer section facing each other,
In a color image forming apparatus in which color images of different colors are sequentially superimposed and transferred to the same position of the transfer material wound around the transfer drum, the transfer materials are fed toward the clamp member while being overlapped. When it has been done, while separating the other transfer material that has not yet been clamped from the transfer material that is in contact with the transfer drum, change the orientation so that this transfer material does not face the transfer part. We propose a configuration in which a transfer material separation guide member is provided to be changed.

It is effective that the transfer material separation guide member is a brush roller that is rotationally driven so that the outer peripheral portion slides in a direction opposite to the moving direction of the surface of the transfer drum.

Further, it is effective that the transfer material separation guide member is an elastic member whose tip end side is urged in the counter direction along the peripheral surface of the transfer drum.

Further, it is effective that the transfer material separation guide member is integrated with a transfer drum unit to which the transfer drum is assembled.

Further, it is effective that the brush roller is rotationally driven by a transfer material conveying drive system or a transfer drum rotational drive system.

Further, it is effective that the transfer material separation guide member is supported so as to be separated from the transfer drum so as not to disturb the unfixed transfer image on the transfer material wound around the transfer drum.

[0019]

FIG. 1 shows a state in which two transfer sheets, which are an example of a transfer material, have been stacked and fed from a paper feeding section, and the uppermost transfer sheet P ₁ is placed on a transfer drum 2. It is the transfer paper on the contact side. Reference numeral 12 indicates that the leading end side of the transfer paper P ₂ that has not yet been clamped is separated from the transfer paper P ₁ on the side in contact with the transfer drum 2 after passing through the clamp member 3. Meanwhile, this transfer paper P ₂
It is a transfer material separation guide member that changes the direction so as not to face the transfer unit 7 and the direction opposite to the transfer unit. In this example, the transfer material separation guide member is a brush roller. The brush roller 12 is installed between the registration roller pair 6 and the transfer portion 7 so as to be in contact with the transfer drum 2.

Further, as shown in FIG. 2, the front end of the transfer paper P ₁ is abutted against the inner part of the clamp member 3, and thereafter,
As the clamp member 3 is closed at the portion A, the brush roller 12 is provided on the downstream side of the portion A in the rotation direction of the transfer drum 2.

The brush roller 12 is rotatably driven in the direction of the arrow shown in the figure so that the peripheral portion of the brush roller 12 contacts the surface of the transfer drum 2 so that the brush roller 12 slides in a direction opposite to the moving direction of the surface. There is.

The other structure is the same as that of the color image forming apparatus shown in FIG.

In the case where the transfer papers are fed from the paper feeding unit 4 (FIG. 8), the next transfer paper is slightly shifted backward from the uppermost transfer paper. Are generally increasing. As shown in FIG. 2, such a transfer sheet does not contact the clamp member 3 at its tip side, and is, so to speak, a transfer sheet in which a clamping error has occurred. Alternatively, among the plurality of transfer sheets fed with the leading edges aligned, the transfer sheet not in contact with the transfer drum 2 may not be clamped. When the leading end of the transfer paper P ₂ having such a clamping error reaches the portion of the brush roller 12, the leading end is separated from the transfer paper P ₁ by the brush roller 12, as shown in FIG. , B opposite to the transfer part
Be guided in the direction. That is, the brush roller 12 both peels the leading edge of the transfer paper and guides the leading edge of the transfer paper downward.

As described above, the transfer paper having the erroneous clamp cannot pass through the transfer portion 7, and therefore, the jamming from the cleaning device 11 to the registration roller pair 6 as shown in FIG. Does not occur.

It is extremely easy to provide a predetermined jam detection sensor on the moving path of the transfer paper which advances in the B direction, and by providing it at such a location, the machine can be stopped immediately. In this way, the transfer paper P ₂ can be immediately taken out of the machine. And this taking out becomes easy.

The brush roller 12 may be independently driven by a motor, but this drive is also performed by a transfer paper transport drive system (rotational drive system such as the registration roller pair 6). By doing so, it is possible to eliminate the need for a motor dedicated to the brush roller, which is advantageous in terms of cost and simplifies the device configuration.

In an image forming apparatus of this type in which the transfer drum 2 is rotationally driven by a dedicated motor, the rotation of the motor is transmitted to the brush roller 12 via a gear, a belt, a chain or the like. Even if it does in this way, the drive motor for exclusive use of the brush roller 12 becomes unnecessary.

As shown in FIG. 4, the transfer drum 2 is assembled into a bracket 15 or the like to constitute a transfer drum unit, and each unit can be attached to and detached from the image forming apparatus main body in the axial direction of the transfer drum. It is like this.

In the case where the brush roller 12 is constituted independently, the transfer drum 2 and the brush roller 12 are rubbed against each other when the transfer drum unit is detached and attached. As shown in FIG. If the structure is integrated with the transfer drum unit, such rubbing can be prevented, and the brush roller and the transfer drum can be prevented from being damaged. Also for maintenance,
This can be done at the same time as the unit, improving this type of maintenance.

By the way, in FIG. 8, when the transfer paper is wound around the transfer drum 2, the first color visible image is transferred at the transfer portion 7, but the transferred image remains unfixed. That is, as long as the transfer paper does not pass through the fixing device, the subsequent superposed images also become unfixed transferred images.

In an image forming apparatus in which the brush roller 12 is still in contact with the transfer drum 2 and the unfixed transfer image is disturbed by the brush roller, the brush roller is used in a timely manner. Such a defect can be prevented by separating from the above.

At the end of the first transfer process, the clamp member 3 approaches the brush roller 12, but before the clamp member 3 passes the brush roller 12,
By separating the brush roller 12 that has been in contact with the transfer drum 2 so far, the first unfixed transfer image on the transfer paper wound around the transfer drum can be prevented from being disturbed. At least, at such time, the brush roller 12 may be separated from the transfer drum 2.

Regarding the contacting / separating operation of the brush roller 12,
For example, such a contacting / separating operation can be performed by the mechanism described below.

As shown in FIG. 4, a solenoid 16 is fixedly mounted on the bracket 15, and when the solenoid 16 is excited, the arm rod 17 pivotally attached to the bracket 15 is attracted at a fulcrum 18, and The brush roller 12 supported by the arm rod 17 is in contact with the transfer drum 2.

When the solenoid 16 is de-energized, the force of the spring 19 causes the arm rod 17 to rotate around the fulcrum 18 in the direction in which the brush roller 12 is separated from the transfer drum 2. Then, the arm rod 17 is stopped by a suitable stopper pin at a predetermined separated position, and in this state, the brush roller 12 is held at a position separated from the transfer drum 2.

As shown in FIG. 5, a filler 21 is provided on the end surface of the transfer drum 2, and a sensor 22 is installed on the main body of the image forming apparatus. When the filler 21 passes the sensor 22, the home position of the transfer drum 2 is set. Is detected and the excitation of the solenoid 16 is released when the timing from this detection to the previous timing is reached, the brush roller 12 is timed to the intended time,
It can be separated from the transfer drum 2.

As for the contact / separation mechanism of the brush roller 12, a cam or the like may be used in addition to the solenoid.
You may make it use the sector gear etc. which are driven by rotation of a motor.

In the monochrome copy mode, the transfer drum 2
The brush roller 12 does not necessarily have to be separated from each other because it is only required to rotate once. In any case, when the brush roller 12 is in contact with the transfer drum, the transfer paper separation guide function as described above is performed. In addition to this, the brush roller 12 also achieves a function of removing foreign matters such as “dust”, “dust”, and “thread scraps” on the transfer drum.

In the embodiment described so far, a brush roller is used as the transfer material separation guide member, but the example shown in FIG. 6 is a thin plate-shaped member as the transfer material separation guide member. The elastic member 24 is used.

The elastic member 24 is installed so that the tip end side of the elastic member 24 strikes the counter direction along the peripheral surface of the transfer drum 2. Then, the portion in contact with the transfer drum 2 is arranged at a position on the downstream side of the portion A in FIG. 2 (closing position of the clamp member).

[0041] After the clamping member 3 is closed, which although passing through the tip portion of the elastic member 24, this immediately, the tip portion of the transfer sheet P ₂ of next order, as shown in FIG. 7, the elastic member 24 Separated at the tip. And after this separation,
The transfer paper P ₂ is guided in a direction away from the transfer portion.

Even if such an elastic member 24 is used, as shown in FIG.
Therefore, it is possible to prevent a jam from extending over the cleaning device from the pair of registration rollers as shown in FIG. In the case of this example as well, since the transfer paper is jammed at a place where the jam detection can be activated, the machine can be stopped immediately after the jam detection and the removal thereof can be easily performed.

Also in this example, since the elastic member 24 is integrally provided on the transfer drum unit, the elastic member 24 and the transfer drum 2 do not rub against each other when the transfer drum unit is attached or detached. The elastic member 24 and the transfer drum are not damaged. Also, the maintainability becomes good as in the previous embodiment.

Also in the case of this embodiment, the elastic member 24 can be separated from the transfer drum so as not to disturb the unfixed transfer image on the transfer paper.

For example, as shown in FIG. 6, the elastic member 24
When the base end is fixed to the swing member 25 and the solenoid 26 is excited, the solenoid pulls the swing member 25, and the tip end side of the elastic member 24 is pressed against the transfer drum 2. I am letting you. In the separation time machine as described above, the excitation of the solenoid 26 is released, and the swing member 25 is pulled left by the spring 27 to rotate counterclockwise around the pivot 28. When the elastic member 24 is stopped by the stopper pin 29, its counterclockwise rotation ends,
In this state, the elastic member 24 is held at a position separated from the transfer drum 2.

Also in the case of this example, it is possible to prevent the unfixed toner image from being disturbed by using such a contact / separation drive mechanism of the elastic member. The elastic member 2
If a polyester film or the like is used as the material of 4, the cost is advantageous and the transfer drum 2 can be prevented from being damaged.

[0047]

According to the color image forming apparatus of the present invention, the jam of the transfer material is spread from the clamp portion side of the transfer material to the process equipment device on the exit side of the transfer section via the transfer section. When the process equipment is a cleaning device, it is possible to prevent the collected developer from overflowing. Further, the transfer material in which the clamping error has occurred can be guided to the portion where the jam can be easily detected, the machine can be stopped immediately, and the transfer material in which the jam has occurred can be easily taken out.

According to the color image forming apparatus of the second aspect, it is possible to more reliably guide the separation of the transfer material having the clamping error. It is also possible to remove foreign matters such as "dust" from the transfer drum with a brush roller.

According to the color image forming apparatus of the third aspect, the structure of the transfer material separation guide member is simplified, and it is not necessary to provide any means for rotationally driving it.

According to the color image forming apparatus of the fourth aspect, the transfer drum is not damaged when the transfer drum unit is attached or detached, and the maintainability is further improved.

According to the color image forming apparatus of the fifth aspect, the rotation driving means dedicated to the brush roller is not required, the apparatus structure can be further simplified, and the cost becomes advantageous.

According to the color image forming apparatus of the sixth aspect, the unfixed toner image on the transfer material can be prevented from being disturbed.

[Brief description of drawings]

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

FIG. 2 is a schematic configuration diagram of a peripheral portion of a transfer paper clamp.

FIG. 3 is a diagram showing that the transfer paper on which a clamping error has occurred is separated by a brush roller.

FIG. 4 is a perspective view showing an example of a contact / separation drive mechanism for a brush roller.

FIG. 5 is a perspective view showing one example of means for detecting a home position position of a transfer drum.

FIG. 6 is a diagram showing a configuration using an example of another transfer material separation guide member.

FIG. 7 is a view showing that a transfer paper having a clamping error is separated by an elastic member that is an example of another transfer material separation guide member.

FIG. 8 is a diagram showing a defect mode of a conventional example.

[Explanation of symbols]

2 transfer drum 3 Clamp member 7 Transfer part 12 brush roller 24 Elastic member

Claims (6)

[Claims] 1. A latent image carrier on which color images of different colors are sequentially formed, a transfer drum which is arranged so as to face the latent image carrier, and which winds a transfer material around a peripheral surface, and the transfer drum. And a clamp member for clamping the front end of the fed transfer material on the transfer drum, and the latent image carrier and the transfer drum are wound around the transfer drum at the transfer portion facing each other. In a color image forming apparatus that sequentially transfers color images of different colors to the same position of the transfer material, when multiple transfer materials are fed toward the clamp member while overlapping, transfer A transfer material separation guide portion that separates another transfer material that has not yet been clamped from the transfer material that is in contact with the drum, and changes the direction so that this transfer material does not face the transfer portion. A color image forming apparatus comprising a material. 2. The color image forming method according to claim 1, wherein the transfer material separation guide member is a brush roller that is rotationally driven so that the outer peripheral portion slides in a direction opposite to the moving direction of the surface of the transfer drum. apparatus. 3. The color image forming apparatus according to claim 1, wherein the transfer material separation guide member is an elastic member whose tip end side is abutted in the counter direction along the peripheral surface of the transfer drum. 4. The color image forming apparatus according to claim 1, wherein the transfer material separation guide member is integrated with a transfer drum unit to which the transfer drum is assembled. 5. The color image forming apparatus according to claim 2, wherein the brush roller is rotationally driven by a transfer material conveying drive system or a transfer drum rotational drive system. 6. The transfer material separation guide member is supported so as to be separated from the transfer drum so as not to disturb the unfixed transfer image on the transfer material wound around the transfer drum.
6. The color image forming apparatus according to any one of 5 to 5.