JPH11102094A - Image forming device - Google Patents

Abstract

(57) [Problem] To provide a simple image forming apparatus with good operability, which is capable of separating a transfer unit from an image carrier either automatically or manually with a simple configuration. The transfer unit is movable between a first position and a second position, and the transfer unit is moved to a first position or a second position by moving the transfer unit in a predetermined manner. In an image forming apparatus having a pressure oscillating cam (position selecting means) 54 for selectively moving, a handle (first driving means) 55 for moving the pressure oscillating cam 54 reciprocates. Cam (second driving means) 59
Is provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention generally relates to a method of forming a visible toner image on an image carrier by an electrophotographic recording method or an electrostatic recording method, and transferring the toner image to a transfer material. The present invention relates to an image forming apparatus for obtaining

[0002]

2. Description of the Related Art An image forming apparatus employing an electrophotographic recording method forms a latent image on a photosensitive drum as an image carrier using light, magnetism, electric charge, and the like, and develops the latent image to form a toner. An image forming unit that visualizes the image, a transfer material conveying unit that conveys the transfer material to a transfer position of the image forming unit (hereinafter, referred to as a transfer unit), and the toner image on the transfer material on which the toner image has been transferred at the transfer position And fixing means for fixing the image.

As the transfer unit, a transfer unit having a transfer material transfer belt which is a belt-shaped transfer member is used from the viewpoint of transferability, and image forming sections for each color are arranged along the transfer belt. For example, recording paper as a transfer material is
It is held on the conveyor belt by electrostatic attraction, and is sequentially conveyed to the transfer position of the image forming unit of each color by the rotation of the conveyor belt,
Further, the sheet is transported to the fixing unit.

The above-mentioned transport belt is stretched and supported by one driving roller and at least one driven roller, and is configured as an endlessly rotating transfer material transporting means. The conveyance belt is devised so as to be stretched with a constant force between the drive roller and the driven roller, and the conveyance belt on the side facing the image forming unit is not loosened by disposing the drive roller downstream in the conveyance direction. It is devised as follows. As a result, the conveyor belt moves at a constant speed from the most upstream image forming section to the most downstream image forming section.

[0005] The toner image of each color formed on the image carrier of each image forming unit is sequentially placed on the recording paper sucked and held on the conveying belt and conveyed to the transfer position of each image forming unit. The image is superimposed and transferred.

By the way, the transfer unit is constructed so as to be able to be pulled out at the time of jam clearance or maintenance, so that when the transfer unit is pulled out, it can swing around a driving roller, for example, so as to separate the image forming section from the transfer belt. Is configured. This rocking mechanism automatically interposes the recording sheet between the transfer unit and each image forming unit when the apparatus stops when a jam occurs, and automatically separates the sheet so as not to damage the image carrier, and automatically returns after the jam is cleared. It has a configuration.

The recording paper on which the toner images of the respective colors have been transferred undergoes color mixing and fixing of the toner images of the respective colors by heat and pressure in a fixing unit disposed close to the downstream side in the transport direction of the transport belt. Thus, a full-color print image is formed.

[0008]

However, the conventional image forming apparatus has the following problems.

That is, since the transfer unit is automatically brought into and out of contact before and after the jam processing, the transfer unit cannot be separated when the power of the apparatus is not turned on. If the transfer unit is to be pulled out in this state, the image forming unit and The transfer unit is deformed. Specifically, it is difficult to perform a jam process when the power supply is momentarily interrupted due to a power failure or the like during image formation.

In order to solve this, there is an example in which an automatic swing mechanism and a manual swing mechanism are provided independently.
The mechanism becomes complicated, resulting in an increase in the size and cost of the apparatus.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and has as its object a simple structure with good operability in which the transfer unit can be separated from the image carrier either automatically or manually. It is to provide a simple image forming apparatus.

[0012]

SUMMARY OF THE INVENTION In order to achieve the above object, according to the present invention, a unit movable between a first position and a second position, and a unit movable in a predetermined manner. And a position selecting means for selectively moving the unit to the first position or the second position by causing the image forming apparatus to have two driving means for moving the position selecting means. It is characterized by having been provided above.

According to a second aspect of the present invention, in the first aspect of the invention, at least one of the driving means is of a manual type and at least one of the other driving means is of an automatic type. Features.

According to a third aspect of the present invention, in the first or second aspect of the invention, one of the driving means moves the position selecting means in a rotating direction, and the other of the other driving means. One of the features is to move the position selecting means in a linear direction.

According to a fourth aspect of the present invention, at least one image carrier fixedly disposed in the image forming apparatus main body and a transfer material for receiving a transfer of a toner image on the image carrier are held and held. A transfer unit that conveys the image carrier to a transfer position facing the image carrier, a transfer unit disposed so as to be able to move freely toward and away from the image carrier, and moving the image carrier itself in a predetermined direction. In an image forming apparatus including: a position selecting unit that achieves contact and separation between an image carrier and a transfer unit; a paper jam detecting unit that detects a paper jam; and a control unit that controls a detection signal from the paper jam detecting unit. First driving means for manually moving the position selecting means in the rotating direction; and moving the position selecting means in a linear direction by a signal from the control means when the image carrier and the transfer unit are in contact with each other. Characterized in that a, the second drive means to separate the transfer unit and the image carrier by.

According to a fifth aspect of the present invention, in the fourth aspect, the position selecting means is an eccentric cam, and the first driving means is fixed or engaged with a shaft of the eccentric cam. The handle is a rotatable handle, and the second driving means is a driving means for moving the eccentric cam in the axial direction to release the engagement with the transfer unit.

According to a sixth aspect of the present invention, in the fifth aspect of the present invention, the eccentric cam is manually moved in a rotational direction at a first position to move the transfer unit with respect to the image carrier. A first cam surface for moving the transfer unit away from the image carrier at a second position axially moved from the first position by the second driving means; The second driving means includes eccentric cam urging means for urging the eccentric cam from the second position toward the first position, and the eccentric cam includes:
When the first drive unit is rotated in the separating direction after moving to the second position, the eccentric cam biasing unit returns from the second position to the first position by the eccentric cam urging unit, and engages with the transfer unit. It is characterized in that the contact / separation operation by the first driving means is enabled.

According to a seventh aspect of the present invention, in the invention of the sixth aspect, the second cam surface of the eccentric cam causes the first driving means to move at a second position by a separating action of the transfer unit. It has a shape acting in the separating direction, and when the transfer unit is separated by the second driving unit, the first driving unit is synchronously moved to the separated position.

[0019]

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

FIG. 1 is a cross-sectional view of an image forming apparatus according to the present invention. Hereinafter, an image forming method is an electrophotographic method, and a plurality of image forming units considered to be particularly effective for the present invention are arranged in parallel. A description will be given of a color image output device to be arranged.

The image output unit 1P of the image forming apparatus according to the present embodiment is roughly divided into an image forming unit 10 (four stations a, b, c, and d are arranged side by side and have the same configuration). Paper feed unit 20, transfer material transport unit 30
And a fixing unit 40.

Here, each unit will be described in detail.

The image forming section 10 is configured as follows.

Photosensitive drums 11a to 11 as image carriers
d is pivotally supported at its center and these are driven to rotate in the direction of the arrow. The primary chargers 12a to 12d face the outer peripheral surfaces of the photosensitive drums 11a to 11d and rotate in the rotation direction thereof.
Optical systems 13a to 13d and developing devices 14a to 14d are arranged.

Each of the primary chargers 12a to 12d applies a uniform amount of charge to the surface of each of the photosensitive drums 11a to 11d.

Next, a light beam such as a laser beam modulated according to a recording image signal by the optical systems 13a to 13d is exposed on the photosensitive drums 11a to 11d to form an electrostatic latent image thereon.

By the way, the developing devices 14a to 14d store developers (hereinafter, referred to as toners) of four colors of yellow, cyan, magenta and black, respectively.
These are the photosensitive drums 11a-1 of the stations a-d.
The electrostatic latent image formed in 1d is developed and visualized as a toner image.

Note that, on the downstream side of the image transfer areas Ta to Td, the photosensitive drums 11a to 11d are not transferred to the recording paper P.
cleaning devices 15a to 15d
Thus, the surfaces of the photosensitive drums 11a to 11d are cleaned.

The paper feed unit 20 includes a cassette 21 for storing the recording paper P, and a pickup roller 2 for feeding out the recording paper P one by one from the cassette 21.
2. Recording paper P sent out from pickup roller 22
Rollers 23a and 23b for transporting the recording paper P to the registration roller rollers 25a and 25b, the paper supply guide 24, and the registration roller 25 for sending the recording paper P to the transfer unit 30 in accordance with the image forming timing of the image forming unit.
a, 25b, and a suction guide 26 for guiding the recording paper P to the transfer unit 30.

Next, the transfer unit 30 will be described.

The recording paper holding sheet 31a is interposed between the belt driving roller 32 and the driven roller 33 and the tension roller 34.
To form a transfer belt 31, and an image transfer plane A is formed between the belt driving roller 31 and the driven roller 33 of the transfer belt 31. In addition, as a material of the recording paper holding sheet 31a, PET (polyethylene terephthalate), PVdF (polyvinylidene fluoride), or the like is used. Further, an appropriate tension is applied to the transfer belt 31 by the tension roller 34.

Then, the transfer belt 31 and the photosensitive drum 11
A small gap of about 1 mm is formed in a to 11d.

An adsorption charger 27 is disposed at a position where the recording paper P sent from the registration rollers 25a and 25b enters the transfer belt 31, and each of the photosensitive drums 11a to 11d and the transfer belt 31 downstream therefrom are attached. The transfer charging blades 35a to 35d are provided in the image transfer areas Ta to Td facing each other.
Is arranged.

The transfer charging blades 35a to 35d can be pressed against and separated from the photosensitive drums 11a to 11d by a mechanism (not shown).
Is lifted and pressed against the photosensitive drums 11a to 11d with an appropriate pressure to perform good image transfer.

A charging / discharging device 36 for separating and removing electricity is disposed slightly upstream of the driving roller 32, and a discharging device 37 for applying a uniform charge to the surface of the transfer belt 31 and a transfer belt 31 downstream thereof. And a brush roller 38 for cleaning the recording paper holding surface.

The fixing unit 40 includes a fixing roller 41a having a heat source such as a halogen heater therein, and a pressing roller 41b pressed against the fixing roller 41a. A), an entrance guide 43 for guiding the recording paper P to the nip portion between the rollers 41a and 41b, and an inner discharge roller 44 for further guiding the recording paper P discharged from the rollers 41a and 41b to the outside of the apparatus. And an external discharge roller 45 and the like. Here, the distance between the fixing roller 41a and the driving roller 32 is set to about 100 mm or less.

Next, the operation of the image forming apparatus will be described.

When the image forming operation start signal is issued, first, the recording paper P is fed out of the cassette 21 one by one by the pickup roller 22. Then, the recording paper P is guided between the paper feed guides 24 by the paper feed rollers 23a and 23b, and is conveyed to the registration rollers 25a and 25b. At this time, the registration rollers 25a and 25b are stopped, and the leading end of the recording paper P is
5b.

Thereafter, the registration rollers 25a and 25b are synchronized with the timing when the image forming section starts forming an image.
Starts spinning. The registration rollers 25a, 25
The rotation timing of the recording paper P and the photosensitive drums 11a to 11d
The timing is set so that the upper toner image exactly matches the image transfer areas Ta to Td.

The recording paper P is moved by the driving roller 32 of the transfer belt 31.
When the recording paper P rushes upward and comes into contact, the recording paper P
Is electrostatically attracted to the recording paper holding sheet 31a by the Coulomb force generated on the recording paper holding sheet 31a.

Incidentally, the transfer belt 31 is
The recording paper P is rotated in synchronization with 1a to 11d, and is conveyed to the first image transfer area Ta while being held thereon. Here, a high voltage is applied to the transfer charging blade 35a pressurized at the start of the sequence in accordance with the passage timing of the recording paper P.

Then, the toner image formed on the photosensitive drum 11a by the above-described process is transferred onto the surface of the recording paper P, and thereafter, the recording paper P is further transferred to the next image transfer area T.
b. At the next station b, image formation is performed with a delay of the time required for the recording paper P to be conveyed between the stations a and b, and the registration rollers 25a and 25b are put on the previous image and the next image is formed. The toner image will be transferred.

In the following, the same steps are repeated, and the recording paper P
On the top, four color toner images are finally transferred in a multiplex manner.

When the above-described multiple transfer is completed, the adsorbing force between the recording paper P and the recording paper holding sheet 31a is reduced by the operation of the separating / discharging charger 36 in the separation section, and the recording paper is subsequently determined by the curvature of the driving roller 32. P is separated from the transfer belt 31.

The recording sheet P separated from the transfer belt 31 is guided by the entrance guide 43 and
And the toner image is fixed by heat and pressure by passing through a nip portion between the fixing roller 41a and the pressure roller 41b. Thereafter, the recording paper P is transferred to the inner and outer discharge rollers 44,
The sheet is discharged outside the apparatus by 45 and stacked on a sheet discharge tray 46.

Then, transfer charging blades 35a-35
d is released, and the transfer belt 31 is moved
The sequence is terminated in a state where the photosensitive drums are separated from the photosensitive drums 11a to 11d in order to protect the photosensitive drums 11a to 11d by minimizing an external force.

Here, a characteristic configuration of the image forming apparatus according to the present embodiment will be described.

The transfer unit 30 is generally constructed so that it can be pulled out of the apparatus body in consideration of the operability at the time of jam clearance and maintenance.

However, since the transfer belt 31 is in contact with the photosensitive drums 11a to 11d at the time of image formation, it is possible to pull out the transfer unit 31 once the transfer belt 31 is separated from the photosensitive drums 11a to 11d. It is necessary to adopt a simple configuration.

When the transfer belt 31 is pulled out while the transfer belt 31 and the recording paper P straddling the upstream and downstream sides of the transfer belt 31 remain at the time of the jam, if the recording paper P is a thick paper, May deform the transfer unit 30 and units disposed upstream and downstream of the transfer unit 30. Therefore, at the time of jam clearance, it is necessary to move the recording paper P and then pull out the transfer belt 31 so that the recording paper P does not straddle the upstream and downstream units. At this time, if the transfer belt 31 is not separated from the photosensitive drums 1a to 11d, the photosensitive drums 11a to 11d
d is damaged, and the transfer unit 30 and the guide portion are deformed by the stiffness (rigidity) of the recording paper P.

Therefore, when the image forming apparatus detects the jam, the transfer unit 30 automatically switches the photosensitive drums 11a to 11a.
After the transfer belt 31 is separated from the transfer belt 31, it is necessary to move the transfer belt 31 and the recording paper P straddling the upstream and downstream sides of the transfer belt 31 so that the transfer belt 31 can be pulled out.

Further, as described in the conventional example, it is necessary to balance both manual separation and automatic separation so that the transfer unit 30 can be pulled out even when the power is not turned on.

This embodiment is characterized in that the above requirements are satisfied.

FIG. 2 is a front sectional view of the periphery of the transfer unit showing a state where the transfer unit is in contact with the photosensitive drum in the image forming apparatus according to the present embodiment, and FIG. 3 shows a state where the transfer unit is separated from the photosensitive drum. FIG. 4 is a front sectional view of the vicinity of a transfer unit.

The transfer unit 30 is stretched by a drive roller 32, a driven roller 33, a tension roller 34, transfer charging blades 35a to 35d, a frame 39 for supporting these, and the rollers 32, 33, and 34. The transfer belt 31 is configured.

Thus, in the present embodiment, the transfer unit 30 uses the drive roller 32 as the center of swing to rotate the photosensitive drum 11.
It is configured to be swingable in a direction of coming and going with respect to a to 11d.

The transfer unit 30 includes the photosensitive drum 11
It is configured to be able to be pulled out to the near side while being separated from a to 11d.

More specifically, as shown in FIG. 2, when the transfer unit 30 is brought into contact with the photosensitive drums 11a to 11d, the frame 39 is pressed by the pressing means 53 provided at a position facing the drive roller 32. The transfer unit 30 is fixed by rotating the drive roller 32 about the swing center and bringing the protrusion 39 a of the frame 39 into contact with the abutting portion 110 on the photosensitive drum 11 a to 11 d side.

Further, as shown in FIG.
In order to separate the projection 39b from the photosensitive drums 11a to 11d, the pressure swing cam 54 is manually rotated by the handle 55, and the pressure means 53 is rotated in the pressure release direction to support the projection 39b of the frame 39 in the transfer unit support. Guide part 52a of table 52
Lock on top. In this state, the transfer unit 30 is placed on the left rail 56 via the rail frame 51 and on the right rail 57 via the support base 52. Can be withdrawn.

Next, a detailed configuration around the pressurizing means 53 will be described with reference to FIGS. FIG. 4 is a plan view around the pressing means 53 corresponding to FIG. 2 or FIG.

The pressurizing means 53 is fixed on a rotatable pressurizing shaft 53c spanned between the main body front side plate 2b and the main body rear side plate 2a, and as shown in FIG.
At two locations b, the front side and the rear side of the frame 39 are configured to contact and separate from the front side and the rear side of the photosensitive drums 11a to 11d, respectively.

On the other hand, the pressure swing cam 54 is
It is fixed in the rotation direction on a rotatable eccentric shaft 58 spanned between the main body b and the main body rear side plate 2a.
A handle 55 for manually separating the transfer unit 30 from the photosensitive drums 11a to 11d is fixed to the front end of the eccentric shaft 58.

The pressure swing cam 54 contacts and separates the transfer unit 30 from the photosensitive drums 11a to 11d by contacting the back side 53b of the pressure means 53.

The pressing means 53 (53b in FIG. 4)
The cam surface of the pressure swinging cam 54 which is the most distant from the eccentric shaft 58 contacts the other end of the pressing means 53 so as to contact and separate from the frame 39. The transfer unit 30 is separated from the photosensitive drums 11a to 11d by its own weight by the cam surface closest to the eccentric shaft 58 of the swing cam 54 coming into contact with the other end of the pressing means 53.

Further, the transfer unit 30 can automatically move only in the direction of separation, in addition to bringing the photosensitive drums 11a to 11d into and out of contact with each other by manually turning the handle 55.

The configuration will be described below.

The pressure swing cam 54 is fixed to the eccentric shaft 58 in the direction of rotation about the axis, but is movably supported in the axial direction of the eccentric shaft 58.

FIGS. 5A and 5B are front views of the pressure swing cam 54. FIG.

A concave portion 54c is formed in a fitting portion between the eccentric shaft 58 and the pressure swing cam 54, and the pressure swing cam 54 is fixed to the eccentric shaft 58 in the rotation direction by the concave portion 54c. It rotates (oscillates) with the eccentric shaft 58.

The pressure swing cam 54 is attached to the eccentric shaft 58.
The pressurizing swing cam 54 is configured to be movable in the axial direction along the eccentric shaft 58.

Further, as shown in FIG.
Is biased in one direction by a return spring 58a contracted between it and the stopper 58b to contact the stopper 58c. The pressure swing cam 54 has two different cam surfaces 54a and 54b formed in the axial direction of the eccentric shaft 58, and manually moves the transfer unit 30 toward and away from the photosensitive drums 11a to 11d. Sometimes cam surface 54
a is in contact with the other end of the pressing means 53b (see FIG. 4). Here, the cam surfaces 54a, 54 of the pressure swing cam 54
FIGS. 5A and 5B show the shape of b.

In this image forming apparatus, when the occurrence of a jam is detected, the reciprocating cam 59 is rotated by one rotation according to a jam detection signal from a control unit (not shown).

At first, the pressure swinging cam 54 and the reciprocating cam 59 are not in contact with each other, but as the reciprocating cam 59 rotates, the cam surface of the reciprocating cam 59 comes into contact with the pressure swinging cam 54 and the return spring 58a The pressing rocking cam 54 is moved toward the eccentric shaft 58 toward the front side against the urging force of.

FIG. 6 is a plan view showing a state where the cam surface of the reciprocating cam 59 is located closest to the eccentric shaft 58 in the near side, and FIG. 7 is a front view of the same.

At this time, the pressurizing means 53b is in contact with one cam surface 54b of the pressurizing oscillating cam 54. The force in the direction of the arrow B is applied by the contact force in the direction of the arrow A in FIG. 7 to generate a moment in the direction of the arrow C. Then, the transfer unit 30 moves the photosensitive drums 11a to 11d by its own weight.
Separate from.

At the same time, the eccentric shaft 58 and the handle 5 fixed thereto are actuated by the action of the moment of the pressure swinging cam 54.
5 rotates in the separating direction.

FIG. 8 is a plan view showing a state after the reciprocating cam 59 makes one rotation, and FIG. 9 is a front view of the same.

The pressure swing cam 54 is about to return to the back side of the eccentric shaft 58 by the urging force of the return spring 58a, but contacts the end 53d of the pressure means 53 and holds it at the position shown in FIG. Have been. The pressurizing unit 53 is rotated in the separating direction by the weight of the transfer unit 30.

By the way, the contact area of the end 53d of the pressurizing means 53 decreases in accordance with this rotation, and the rotational force of the transfer unit 30 due to its own weight acts on the pressurizing means 53 (with the transfer unit 30). The contact portion between the two decreases while the pressurizing means 53 is in contact, and the pressurizing swing cam 54 returns to the initial position where it comes into contact with the stopper 58c (that is, the cam surface 5).
4a and the pressing means 53b are engaged), and the transfer unit 30 is moved to the photosensitive drum 11a in a state where the transfer unit 30 can be manually moved toward and away from the photosensitive drums 11a to 11d.
11d (state shown in FIG. 3).

As described above, the state is the same between when the transfer unit 30 is manually separated from the photosensitive drums 11a to 11d and when it is automatically separated from the photosensitive drums 11a to 11d. The performance is improved.

Thus, according to the present embodiment, it is possible to automatically separate the transfer unit 30 from the photosensitive drums 11a to 11d at the time of jam clearance, and even when the power to the apparatus main body is not turned on. The transfer unit 30 can be manually separated and pulled out, and a simple image forming apparatus with good operability can be realized.

The present invention is, of course, not limited in its application to the relationship between the transfer unit and the photosensitive drum. For example, the present invention automatically swings and separates during jam processing.
The present invention can be similarly applied to a conveyance guide or the like in a paper conveyance path which manually comes back into contact after the jam processing.

[0083]

As is apparent from the above description, according to the present invention, at least one image carrier fixedly disposed on the main body of the image forming apparatus, and the transfer of the toner image on the image carrier. A transfer unit that includes a transfer belt that holds a transfer material to receive and transfers the transfer material to a transfer position facing the image carrier, and a transfer unit that is disposed so as to be freely movable toward and away from the image carrier,
A paper jam detecting means for detecting a paper jam, wherein the image forming apparatus comprises: a position selecting means for moving the image carrier and the transfer unit toward and away from each other by moving itself in a predetermined direction. Control means for controlling a detection signal from the clogging detection means; first driving means for manually moving the position selection means in the rotation direction; and A second driving means for separating the image carrier and the transfer unit by moving the position selecting means in a linear direction by a signal, so that the transfer unit can be automatically and manually moved from the image carrier by a simple configuration. The effect is obtained that a simple image forming apparatus with good operability, which can be separated in any case, can be realized.

[Brief description of the drawings]

FIG. 1 is a sectional view of an image forming apparatus according to the present invention.

FIG. 2 is a front sectional view around the transfer unit showing a state where the transfer unit is in contact with a photosensitive drum in the image forming apparatus according to the exemplary embodiment;

FIG. 3 is a front sectional view around the transfer unit in a state where the transfer unit is separated from the photosensitive drum in the image forming apparatus according to the exemplary embodiment;

FIG. 4 is a plan view of the vicinity of a pressing unit.

FIG. 5 is a front view of the pressure swing cam.

FIG. 6 is a plan view showing a state where the cam surface of the reciprocating cam is located closest to the eccentric axial direction.

FIG. 7 is a front view showing a state where the cam surface of the reciprocating cam is located closest to the eccentric axial direction.

FIG. 8 is a plan view showing a state after the reciprocating cam makes one rotation.

FIG. 9 is a front view showing a state after the reciprocating cam makes one rotation.

[Explanation of symbols]

11a to 11d Photosensitive Drum (Image Carrier) 30 Transfer Unit 31 Conveying Belt 53 Pressing Means 54 Pressing Oscillating Cam (Eccentric Cam: Position Selecting Means) 54a, 54b Cam Surface 55 Handle (First Driving Means) 58 Eccentric shaft 58a Return spring (eccentric cam biasing means) 59 Reciprocating cam (second drive means) P Recording paper (transfer material)

Claims (7)

[Claims] 1. A unit movable between a first position and a second position, and selectively moving the unit to the first position or the second position by moving itself in a predetermined manner. An image forming apparatus comprising: a position selecting unit configured to move the position selecting unit; and two or more driving units configured to move the position selecting unit. 2. The image forming apparatus according to claim 1, wherein at least one of the driving units is a manual type, and at least one of the other driving units is an automatic type. 3. One of the driving means moves the position selecting means in a rotating direction, and one of the other driving means moves the position selecting means in a linear direction. The image forming apparatus according to claim 1, wherein: 4. An image forming apparatus comprising: at least one image carrier fixedly disposed in a main body of an image forming apparatus; and a transfer material for receiving a transfer of a toner image on the image carrier. A transfer unit including a transfer belt for transferring to an opposed transfer position, the transfer unit being disposed so as to be able to freely contact and separate from the image carrier, and the image carrier and the transfer unit by moving itself in a predetermined direction. An image forming apparatus comprising: a paper jam detecting means for detecting a paper jam; a control means for controlling a detection signal from the paper jam detecting means; and the position selecting means. A first drive unit for manually moving the position selection unit in the rotation direction, and a position selection unit that is moved in a linear direction by a signal from the control unit when the image carrier and the transfer unit come into contact with each other. An image forming apparatus characterized in that a, the second drive means to separate the transfer unit and the image bearing member Te. 5. The position selecting means is an eccentric cam, the first driving means is a rotatable handle fixed or engaged with a shaft of the eccentric cam, and the second driving means is 5. A driving means for moving the eccentric cam in the axial direction to release the engagement with the transfer unit.
The image forming apparatus as described in the above. 6. The eccentric cam, wherein the eccentric cam is manually moved in a rotation direction at a first position to bring the transfer unit into and out of contact with the image carrier, and a second cam surface; A second cam surface that separates the transfer unit from the image carrier at a second position axially moved from the first position by a driving unit, wherein the second driving unit includes an eccentric cam; First from second position
And an eccentric cam urging means for urging the eccentric cam in the direction of the position, wherein the eccentric cam is moved to a second position and then the eccentric cam is rotated in the separating direction. 6. The image according to claim 5, wherein the cam urging means returns from the second position to the first position, and engages with the transfer unit to enable the contact and separation operation by the first driving means. Forming equipment. 7. The second cam surface of the eccentric cam has a shape that causes the first driving unit to act in a separating direction by a separating action of the transfer unit at a second position. 7. The image forming apparatus according to claim 6, wherein the first drive unit moves to the separated position in synchronization with the separation by the second drive unit.