JP2855000B2 - 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 such as an electrophotographic apparatus or an electrostatic recording apparatus, and more particularly to a method for transferring a toner image formed on an image carrier onto a flexible transfer material supporting member of a transfer apparatus. The present invention relates to an image forming apparatus that electrostatically transfers onto a held transfer material to obtain an image on the transfer material.

[0002]

2. Description of the Related Art For example, in a color electrophotographic copying machine, after a toner image is formed on an image carrier by an electrophotographic method, the toner image is transferred onto a transfer material by a transfer device, and the image is transferred onto the transfer material. It has gained.

A transfer device usually includes a transfer drum as transfer material holding means. The transfer drum is provided in a notch portion of a drum type frame (frame body) having cylindrical both end frames. A transfer material support sheet, usually a transfer material support sheet made of a high resistance film, is wound in a cylindrical shape. The transfer material is supplied to the transfer drum of the transfer device, and is applied and held on the support sheet by applying an electrostatic attraction force between the transfer material support sheet and the transfer material at the transfer material suction position,
Wound on a transfer drum (Japanese Patent Laid-Open No. 55-32079)
No.).

[0004] At the transfer material adsorbing position, an adsorbing charger composed of a corona charger is disposed inside (back side) across the transfer material carrying sheet, and is opposed to the outside and is in contact with the transfer material outside. A contactable conductive roller (charge injection roller) is provided. The transfer material is fed from a paper feed unit, and is sent to a transfer material suction position on the carrying sheet at a predetermined timing by a conveyance roller. Then, by applying and injecting a charge having a polarity opposite to the charge of the toner constituting the toner image on the image carrier to the transfer material with the attraction charger and the conductive roller, the toner is electrostatically attracted onto the carrier sheet, Will be retained.

The transfer material adsorbed and held on the transfer material carrying sheet is transported a plurality of times to an image transfer position facing the image carrier by rotating the transfer drum, and a toner image of each color is placed on the image carrier. Each time is formed, the toner image is electrostatically transferred onto the surface of the transfer material, thereby obtaining a color image obtained by multiple transfer of the toner images of a plurality of colors onto the transfer material.

[0006]

By the way, the conductive roller is brought into contact with the transfer sheet immediately before the transfer material arrives at the transfer material suction position of the transfer material support sheet when the transfer material is sucked.
The transfer material is held in contact with the transfer sheet sandwiched between the carrier sheets and is rotated by the rotation of the transfer drum while being driven to rotate, thereby adsorbing and holding the transfer material at the same speed as the rotation speed of the transfer drum.
After the transfer, the rear end of the transfer material passes through the transfer material suction position,
The contact is released by retracting from the transfer drum.

When the above-mentioned conductive roller first comes into contact with the transfer material carrying sheet, the conductive roller comes into contact with the frame of the transfer drum. A sensor or a sensor flag that emits an image formation start signal vibrates. Therefore, only the first color latent image of the multi-color image is formed from a position shifted from the normal position, and as a result, the multi-color image finally obtained on the transfer material is The toner image of the first color is shifted from the toner images of the second and subsequent colors over the entire area in the transport direction.

In recent years, in the copier market, downsizing of the apparatus has been regarded as important, and the size of the transfer material supply unit has also been reduced. Is close to the above-mentioned sensor position and the contact position of the conductive roller to the transfer material carrying sheet (the transfer material suction position).
The influence of the impact at the time of abutment directly shifts the start timing of the image forming signal, so that the color shift tends to be more noticeable.

When a large number of continuous images are formed on a small-sized transfer material in the axial direction of the transfer material carrying sheet (also the axial direction of the conductive roller), the toner is gradually deposited on the non-image portion of the carrying sheet. It is accumulated (so-called fog). Then, when the conductive roller comes into contact with the carrier sheet in an attempt to attract the transfer material onto the carrier sheet, a part of the fog toner in the non-image area is transferred to the conductor roller. Following this, if you try to obtain a copy with a large transfer material,
The image surface of the transfer material is stained by fog toner transferred to the conductive roller.

In order to maintain the toner concentration of the developer at an appropriate level, a patch image of a constant density level may be formed on the image carrier, and the density may be read to control the toner concentration of the developer. However, in this case, a part of the toner of the patch image may be transferred to the conductive roller via the transfer material carrying sheet. For this reason, a cleaning member for the conductive roller is provided, but this cleaning member increases the rotational load of the conductive roller.

Further, since the conductive roller contacts the transfer material carrying sheet and is driven by the transfer drum, a load fluctuation is applied to the rotation of the transfer drum when the conductive roller comes into contact and when the contact is released. There is also. Transfer drum is PL
Although constant rotation control is performed by L control or the like, constant rotation of the transfer drum is hindered by contact and release of the conductive roller. This load variation is performed from immediately before the leading end of the transfer material reaches the transfer material suction position of the carrier sheet to immediately after the rear end of the transfer material passes through the suction position. Image formation, development, occurring during the transfer process, due to local rotation fluctuations of the transfer drum due to load fluctuations in such contact and release of the conductive roller, color shift and color unevenness in the resulting image, Density unevenness occurs. If the image formation is started after one rotation of the transfer drum for completely adsorbing the transfer material, the above-mentioned problem is solved, but the efficiency of image formation is extremely reduced.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to eliminate the impact caused by the contact of the suction member with the transfer material holding means, and the rotation fluctuation caused by the load change of the transfer material holding means at the time of contact and release of the contact. Another object of the present invention is to provide an image forming apparatus capable of obtaining a high-quality image free from image shift, color shift, and color unevenness on a transfer material.

[0013]

The above object is achieved by an image forming apparatus according to the present invention. In summary, the present invention provides an image carrier that carries an image, a frame, a flexible member that covers a notch of the frame, a transfer material carrier that carries a transfer material, and the transfer material. An adsorbing means for adsorbing the transfer material to the supporting means, wherein the adsorbing means is moved to the first position when the adsorbing operation is performed by passing the transfer material between the transferring material and the transferring material, and An adsorbing member movable to a second position farther from the transfer material carrying means than the first position;
And a pressing member provided on a side of the transfer material supporting unit that does not support the transfer material, the pressing member pressing the flexible member. In the image forming apparatus in which the image is transferred onto the transfer material carried by the unit, the suction member moves the first member from the second position.
When moved to the position, without contacting the frame,
An image forming apparatus, wherein the flexible member contacts the flexible member at a pressing position pressed by the pressing member.
Preferably, the flexible member is a 10-200 μm film. According to one embodiment of the present invention, the image carrier can carry a plurality of color images, and the plurality of color images on the image carrier are transferred to a transfer material carried by the transfer material carrying means. The images are sequentially transferred and superimposed.

[0014]

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

In FIG. 1, reference numeral 1 denotes a photosensitive drum as an image carrier. The photosensitive drum 1 is supported at its center and is driven to rotate in the direction of the arrow. Around the photosensitive drum 1, a primary charger 2, an optical system 3,
A developing device 4 and a toner density sensor 5 are provided.

The primary charger 2 applies uniform primary charging to the photosensitive drum 1, and the optical system 3 applies a color-separated light image or a light image L corresponding thereto to the surface of the photosensitive drum 1 at a predetermined timing. To form an electrostatic latent image. A laser beam scanning device or the like is used for the optical system 3. The developing device 4
In this embodiment, a horizontal moving type developing device which moves in a tangential direction opposite to the surface of the photosensitive drum 1 is used, and a magenta developer, a cyan developer, a yellow developer, and a black developer are used as the developer. 4 developing units 4 specially stored
M, 4C, 4Y and 4B. Developing device 4
A developing device containing toner of a color corresponding to the electrostatic latent image formed on the photosensitive drum 1 is opposed to the photosensitive drum 1, and the toner of the facing developing device is electrostatically charged on the surface of the photosensitive drum 1. And then adheres to the electrostatic latent image, develops the electrostatic latent image, and visualizes it as a toner image.

On the right side of the photosensitive drum 1, a transfer device 6A is provided.
The transfer drum 6 serving as a transfer material holding means is provided so as to be slightly separated from the surface of the photosensitive drum 1.

The transfer drum 6, as shown in FIG.
Cylindrical end frames 6b of a drum frame constituting a frame body
A transfer material carrying sheet 6a, which is a flexible member serving as a transfer material carrying member, is wound in a cylindrical shape in the notch portion between them. Usually, the carrier sheet 6a is made of a high-resistance film, for example, P
VdF and PET are made of a flexible film material having a thickness of about 10 to 200 μm. At the image transfer position facing the photosensitive drum 1, a transfer charger 7 composed of a corona charger is disposed on the side opposite to the transfer material holding surface of the support sheet 6a, that is, inside the transfer drum 6.

The photosensitive drum 1, an optical system 3 for forming a toner image on the photosensitive drum 1, a developing device 4, and a transfer charger 7 for transferring the toner image on the photosensitive drum 1 onto a transfer material.
And the like, an image is obtained on the transfer material.

The transfer drum 6 is driven to rotate in the direction of the arrow,
At the upstream side of the transfer position where the transfer charger 7 is provided, an adsorption charger 19 including a corona charger is provided inside the transfer drum 6.
However, a conductive roller (charge injection roller) 20, which is a suction member grounded as a charge injection means, is disposed outside the support sheet 6a opposite thereto. By gripping the transfer material electrostatically on the support sheet 6a by the suction means including the suction charger 19 and the conductive roller 20, a gripper for gripping and holding the transfer material on the transfer drum 6 is provided. The transfer drum 6 does not need to be provided.

Corona dischargers 10 and 11 for static elimination are disposed outside and inside the transfer material carrying sheet 6a at positions downstream of the transfer position in the rotation direction of the transfer drum 6, respectively. Pressing rollers 12 and 13 for separating the material P from the support sheet 6a are provided, respectively.
Further, a separation blade 14 is provided in the vicinity thereof. At a position downstream of the separation blade 14 in the rotation direction of the transfer drum 6, a brush roller 15 for cleaning the toner attached to the outer surface (transfer material holding surface) of the support sheet 6a is provided. Inside the sheet 6a,
Corona discharger or brush type static eliminator 1 for removing the adhesive force (residual Coulomb force and Van der Waals force) of toner 1
6 are provided.

A fixing device 18 composed of a pair of fixing rollers is disposed adjacent to the transfer drum 6. The fixing device 18 is separated from the supporting sheet 6 a by the separation claw 14 and conveys the toner image on the transfer material P conveyed by the conveyor 17. Fixing is performed.

Further, around the photosensitive drum 1, there are provided a static eliminator 27 for removing electrostatic charges on the surface of the photosensitive drum 1, and a cleaning blade 28 for removing residual toner. Also, if necessary, a corona discharger 29 is provided near the separation claw 14 for the purpose of preventing image disturbance due to peeling discharge that occurs when the transfer material P is separated from the support sheet 6a. It is good to do.

With the above-described structure, the surface of the photosensitive drum 1 is uniformly primary-charged by the primary charger 2, and the optical system 3 irradiates the surface of the photosensitive drum 1 with the optical image L that has first passed through the green filter, for example. Then, an electrostatic latent image mainly composed of the magenta component of the light image L is formed. The developing device 4 moves in a tangential direction with respect to the photosensitive drum 1 in synchronization with the feeding of the electrostatic latent image due to the rotation of the photosensitive drum 1 and transfers the developing device 4M containing magenta toner to the photosensitive drum 1. In opposition, the electrostatic latent image on the photosensitive drum 1 is developed with magenta toner, thereby forming a magenta toner image.

On the other hand, the transfer material P is transferred to upper and lower guides 3 by the action of registration rollers (transfer material transfer rollers) 21a and 21b.
The conductive roller 20 and the suction charger 19 are supplied along the surface of the supporting sheet 6a to the transfer material suction position where the conductive roller 20 and the suction charger 19 are opposed by the upper and lower guides 30 and 22.

The lower guide 22 is supported swingably about a fulcrum 31 and is normally urged clockwise in FIG. 1 by a coil spring 32 of an elastic member. The conductive roller 20 is rotatably attached to the tip of the lower guide 22, and the lower guide 22 is supported by the eccentric cam 33 which is rotated in the direction of the arrow by a driving means (not shown).
When the conductive roller 20 swings around 1, the conductive roller 20 moves away from and closes to the transfer material carrying sheet 6a and conversely approaches the transfer material carrying sheet 6a. According to the present invention, the eccentric cam 33 is driven in synchronization with the supply timing of the transfer material P, thereby controlling the position of the conductive roller 20 and when the transfer material P is supplied to the suction position, as shown in FIG. As shown in FIG. 7, the positioning is performed in a state of contact with the supporting sheet 6a. This will be described later.

In this embodiment, an elastic sheet 2 having a thickness of, for example, 150 μm, which constitutes a suction means at a transfer material suction position.
A pressing member 23 composed of a sheet supporting member 4 and a sheet supporting member 25 is provided to press and hold the supporting sheet 6a from the inside.
The mechanical deformation of the carrier sheet 6a due to the brush roller 15 or the like or the mechanical deformation due to the electrostatic force of the attraction charger 19 is forcibly removed.

In this case, the elastic force of the elastic sheet 24 is such that the direction in which the support sheet 6a is stretched, that is, the direction from the free end of the elastic sheet 24 in contact with the support sheet 6a to the support of the elastic sheet 24 is the moving direction of the support sheet 6a. The direction is preferably opposite to the above, so that the distortion of the support sheet 6a in the thrust direction (the longitudinal direction of the transfer drum) can be reduced. As shown in the figure, the elastic sheet 2 covers the discharge area where the shield member of the adsorption charger 19 is open.
By providing 4, the discharge distribution in the circumferential direction of the adsorption charger 19 can be regulated.

The transfer material P supplied to the transfer material suction position is
Thereafter, the transfer drum 6 is electrostatically adsorbed and held on the supporting sheet 6a by the adsorption charger 19 and the conductive roller 20.
Is conveyed to the image transfer position facing the photosensitive drum 1 by the rotation of. Of course, the timing of the transfer of the transfer material by the registration rollers 21a and 21b and the timing of the formation of the latent image by the optical system 3 are synchronized, and the toner image obtained by developing the latent image on the photosensitive drum 1 and the transfer material The position corresponding to P coincides with the transfer position.

At the image transfer position, the transfer charger 7 operates to generate a transfer electric field, whereby the toner image on the photosensitive drum 1 is continuously transferred onto the transfer material P conveyed by the charge applied to the carrier sheet 6a. Transcribe.

As shown in FIG. 2, when the rear end of the transfer material P passes through the conductive roller 20, the eccentric cam 3
3 is rotated by the driving means to the bottom dead center, whereby the lower guide 22 is pressed downward by the eccentric cam 33 and
As a result, the conductive roller 20 is released from contact with the transfer material carrying sheet 6a and retreats, and is largely separated.

On the lower side of the lower guide 22, a cleaning member 41 directly in contact with the surface of the conductive roller 20 and a sheet-like seal 42 provided from the lower side of the cleaning member 41 to the lower side of the roller 20 are provided. Cleaning means 40 is provided. The cleaning member 41 is made of, for example, an elastic rubber blade, a collecting brush, a sheet scraper, or the like. The conductive roller 20 on which the cleaning member 41 is in contact with the surface is cleaned by the cleaning member 41 when rotated by a driving unit described later. Is performed. As a result, the toner transferred from the support sheet 6a to the surface of the conductive roller 20 is removed, and the cleaned conductive roller 20 is constantly brought into contact with the transfer material P to transfer the transfer material P onto the support sheet 6a. The charge for adsorption is injected well. The toner removed from the surface of the conductive roller 20 by the cleaning member 41 is received by the sheet-shaped seal 42 to prevent the toner from scattering and falling downward.

Now, according to the present invention, the conductive roller 20
Is provided with a driving means different from the transfer drum 6. FIG.
The driving means of the conductive roller 20 will be described on the basis of FIG. FIG. 3 is an axial development in the vicinity of the transfer drum 6 of the image forming apparatus.

As shown in FIG. 3, the drive means 200 for the conductive roller 20 includes a motor M ₂ for the conductive roller 20. The motor M ₂ is located on the right side of the transfer device 6A (in FIG. (The rear side of the transfer drum 6), which is the rear side of the main body side plate 150. Upper registration roller 2
1a is a bearing 20 between the left and right main body side plates 151 and 150.
1 is rotatably supported via a main body side plate 150 at one end protruding from the main body side plate 150 on the right side thereof.
The rotational drive of the motor M ₂ is input to the gear 202. When the electromagnetic clutch gear 202 is ON (drive transmitting state), rotation of the motor M ₂ is transmitted to the upper register roller 21a, the upper registration roller 21
a starts to rotate. The lower registration roller 21b is rotatably supported between the unit side plates 203 and 204 via a bearing 205.
At the position where 1a and 21b are in contact, gears 206 and 207 fixed to one end of the gears are engaged with each other.
As a result, the rotation of the upper registration roller 21a is transmitted, and the lower registration roller 21b starts rotating.
21b rotates.

A fulcrum shaft 31, which is a fulcrum of the lower guide 22, is supported between the unit side plates 203 and 204.
The conductive roller 20 rotatably supported by the lower guide 22 and the bearing 208 at the tip of the lower guide 22 around this.
Can swing together. Lower registration roller 21
The above-mentioned gear 207 fixed to b has an integrated timing pulley 207a, and an integrated timing pulley 209a rotatably supported on the fulcrum shaft 31;
209b, for example, a timing pulley 209
a and a timing belt 210. Further, the other timing pulley 209 b and a timing pulley 211 fixed to one end of the conductive roller 20 are connected by a timing belt 212.

Accordingly, the upper and lower registration rollers 21a, 21
When the roller b rotates, the rotation of the registration roller 21b therebelow is driven by the pulley 207a, the belt 210, and the pulley 20.
9a to the pulley 209b.
9b, the belt 212 and the pulley 211 to the conductive roller 20. As a result, when the upper and lower registration rollers 21a and 21b rotate, the conductive roller 20 rotates synchronously so that the direction of movement of the outer surface facing the transfer drum 6 is the same.

In the present invention, the rotational speed of the conductive roller 20 is the same as the rotational speed of the transfer drum, that is, the moving speed of the outer surface of the conductive roller 20 is substantially equal to the moving speed of the transfer material carrying sheet 6a on the outer surface of the transfer drum 6. The same speed is set. In the present embodiment, the timing pulley 207
a, 209a, 209b, and 211, the rotational speed of the conductive roller 20 is reduced.
The rotation speed was set to be the same as the rotation speed.

On the other hand, the rotation of the photosensitive drum 1 and the transfer drum 6 is performed by a motor M ₁ provided on the same side as the motor M ₂ . The photosensitive drum 1 has its centering plate 15
2 is rotatably supported between the main body 2 and the main body side plate 150 via a bearing 102 on a drum shaft 103, and a gear 104 is fixed to one end of the drum shaft 103 of the photosensitive drum 1 protruding from the main body side plate 150. The rotational drive of the motor M ₁ is input to the gear 104. Thereby, the drum cylinder 101a having the photosensitive layer on the surface and the flanges 1 at both ends are formed.
01b is rotated.

The transfer drum 6 includes a transfer unit side plate 60.
1 and 602, rotatably supported via a bearing 603 on a drum shaft 604, and a transfer gear 6c provided on one flange 6b of the transfer drum 6 and a drum gear provided on one flange 101b of the photosensitive drum 1. 10
1c. Thereby, when the photosensitive drum 1 rotates, the transfer drum 6 rotates integrally with the photosensitive drum 1.

Therefore, the motor M ₁ drives only the photosensitive drum 1 and the transfer drum 6, while the upper and lower registration rollers 21 a and 21 b, which rotate and stop, and the conductive roller 20
To be driven by the motor M ₂ different driving source through the gear 202, the photosensitive drum 1 of course, run out of abutment upon and load variation thereof during release of the abutment of the transfer drum 6 is also conductive roller 20, It is possible to always rotate at a constant speed with a constant load, and image defects such as color misregistration and color unevenness due to rotation speed fluctuations are completely prevented.

According to the present invention, position control means for positioning the conductive roller 20 in contact with the transfer material carrying sheet 6a is provided in the separating / contacting means for the conductive roller 20 including the eccentric cam 33. I have. This will be described. FIG. 4 is a detailed view of a portion K in FIG. 1 and shows a state immediately before the transfer material P is attracted.

In the figure, the eccentric cam 33 has a camshaft 3
The motor 4 is stopped at the top dead center position under the control of a half-rotation control device (not shown) as position control means connected to 4. The conductive roller 20 and the lower guide 22 are supported by a fulcrum shaft 31.
The upper guide is biased upward by the upper coil spring 32, whereby the lower guide 22 comes into contact with the upper dead center of the eccentric cam 33, the suction posture is maintained, and the conductive roller 20 is moved to the transfer material supporting sheet 6a.
Is positioned in contact with the The conductive roller 20 positioned in this contact state is at a position substantially non-contact with both flanges 6 b of the transfer drum 6, and is transferred by pushing the pressing member 23 built in the transfer drum 6 in the outer peripheral direction. Only the material carrying sheet 6a is in contact with the conductive roller 20.

As described above, the position control means including the half-rotation control device is provided in the separation / contact means of the conductive roller 20 including the eccentric cam 33 and the like, so that the conductive roller 20 Since it is positioned in contact with the supporting sheet 6a, it is possible to reduce the impact and vibration caused by the contact of the conductive roller 20 with the supporting sheet 6a.

After the transfer material P is attracted onto the supporting sheet 6a, the cam shaft 34 rotates half a turn, moves backwards to the coil spring 32 at the bottom dead center of the eccentric cam 33, and pushes down the conductive roller 20.
The conductive roller 20 is released from contact with the supporting sheet 6a, and assumes a retreating posture separated from the transfer drum 6. Lower guide 2
2 is always in contact with the eccentric cam 33 by the coil spring 32, so that the conductive roller 20 does not contact the transfer drum 6.

From the above, it is possible to reduce the impact of the conductive roller 20 on the transfer sheet 6 when the conductive roller 20 abuts on the supporting sheet 6a, and to completely eliminate image defects such as color shift caused by the impact of the transfer drum 6. Will be resolved. Thus, according to the present invention,
As described above, the load fluctuation at the time when the conductive roller 20 abuts on the transfer drum 6 and the time when the abutment is released are eliminated, and the rotational speed fluctuation is eliminated.
In combination with the prevention of density unevenness and the like, high quality images free from color shift, color unevenness, density unevenness, etc. can be obtained on the transfer material by image formation.

FIG. 5 shows a means for separating and connecting conductive rollers using a linear stepping motor. Immobile upper guide 30
By controlling the stepping motor 35 fixed to the transfer roller 6, the actuator 36 is moved forward and backward to move the conductive roller 20 closer to and away from the transfer drum 6, and as described above, the actuator 36 The lower guide 22 is always in contact with the terminal 37 by the urging force of the spring 32, and does not give an impact when the transfer drum 6 is in contact with or retracted.

Further, since the drive source of the conductive roller 20 is separated from the transfer drum 6, the conductive roller 20 can be rotated independently of the rotation of the transfer drum 6. The timing may be, for example, immediately before or immediately after the copy sequence or after the jam processing, or the like.
Is rotated when the cleaning means 4 is not in the contact position.
0 completely cleans the surface of the conductive roller 20. As a result, contamination of the image surface of the transfer material P due to toner contamination of the conductive roller 20 is prevented, and uniform charge injection for adsorption to the transfer drum 6 becomes possible.

[0048]

As described above, the image forming apparatus of the present invention comprises an image carrier for carrying an image; a frame; and a flexible member for covering the notch of the frame. Transfer material carrying means for carrying; and suction means for adsorbing the transfer material to the transfer material carrying means, wherein the transfer material is moved to the first position when the suction operation is performed by passing the transfer material between the transfer material carrying means and the transfer material carrying means. A suction member movable to a second position farther from the transfer material holding means than the first position when the suction operation is not performed, and a flexible member provided on the side of the transfer material holding means that does not hold the transfer material, And a pressing member for pressing the elastic member to the outside. In an image forming apparatus in which an image on the image carrier is transferred to a transfer material carried by the transfer material carrying means, ,
When the movable member is moved from the second position to the first position, it does not contact the frame but contacts the flexible member at the pressing position pressed by the pressing member. When the abutment is made on the transfer material holding means, the suction member can prevent the transfer material holding means from giving an impact, prevent the occurrence of image displacement due to the impact, and form on the image holding body. In the case where images of multiple colors are sequentially transferred onto the transfer material carried by the transfer material carrying means, color shift and color unevenness can be prevented, and as a result, a high-quality image can be obtained. it can.

[Brief description of the drawings]

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

FIG. 2 is a diagram illustrating a state in which a conductive roller of a transfer device of the image forming apparatus of FIG. 1 is in contact with a transfer material carrying sheet of a transfer drum.

FIG. 3 is an axial development in the vicinity of a transfer drum of the image forming apparatus.

FIG. 4 is a detailed view of a separating / contacting means for a conductive roller.

FIG. 5 is a detailed view of another example of a conductive roller separating / contacting means.

FIG. 6 is a perspective view of a transfer drum of the transfer device.

[Explanation of symbols]

 Reference Signs List 6 transfer drum 6a transfer material carrying sheet 20 conductive roller 33 eccentric cam 200 conductive roller driving means

Claims (3)

(57) [Claims] 1. An image carrier that carries an image, a frame, and a flexible member that covers a notch of the frame.
A transfer material supporting means for supporting the transfer material; and a suction means for adsorbing the transfer material to the transfer material supporting means, wherein the transfer material is passed between the transfer material supporting means to perform a suction operation. And a suction member movable to a second position farther from the transfer material holding means than the first position when the suction operation is not performed, and the transfer material of the transfer material holding means is held. And a pressing member provided on the non-moving side, the pressing member pressing the flexible member, and the image on the image carrier is transferred to a transfer material carried by the transfer material carrying device. In the image forming apparatus, when the suction member is moved from the second position to the first position, the suction member does not come into contact with the frame body, but at a pressing position pressed by the pressing member. An image forming apparatus contacting the flexible member. . 2. The image forming apparatus according to claim 1, wherein said flexible member is a film having a thickness of 10 to 200 μm. 3. The image carrier is capable of carrying images of a plurality of colors, and the images of the plurality of colors on the image carrier are sequentially transferred onto a transfer material carried by the transfer material carrying means. 3. The image forming apparatus according to claim 1, wherein: