JP2001265127A - Transfer device and image forming device using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a transfer device and an image forming device, capable of thoroughly absorbing an impact generated, when a paper rushes into a nip part and when the paper is separated from the nip part by using a moving means, and capable of forming a proper image. SOLUTION: The device is provided with a press-contact means for bringing a transfer member into press contact with an image carrier or an intermediate transfer body, while controlling the transfer member so as to come into press contact or separate from the image carrier or the intermediate transfer body, the moving means for supporting the transfer member, so as to be rocked and rocking the transfer member according to an external force generated at a process of bringing the recording medium to the press-contact part of the image carrier or the intermediate transfer body with the transfer member, and a positioning means for positioning the rocking direction of the transfer member, so that the rocking direction may be always kept constant with reference to the press-contact direction of the image carrier or the intermediate transfer body with the transfer member.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a color copying machine, a color printer, and the like which employ an image forming system such as an electrophotographic system, an electrostatic recording system, an ionography, and a magnetic recording system.
For image forming apparatuses such as color and facsimile,
In a transfer apparatus and an image forming apparatus using a transfer member for transferring a visible image on an image carrier such as a photoconductor drum or an intermediate transfer body onto a sheet, the speed fluctuation of the image carrier and the intermediate transfer body is suppressed. And an image forming apparatus.

[0002]

2. Description of the Related Art Conventionally, as a transfer device for transferring a visible image formed on an image carrier such as the photosensitive drum or a visible image transferred on an intermediate transfer member onto a sheet, for example, There is known a device using a bias transfer roll which is pressed against such an image carrier or an intermediate transfer member and to which a predetermined bias voltage is applied. In this transfer device, a bias transfer roll is pressed against a photosensitive drum on which a toner image is formed while rotating at a predetermined speed with a predetermined contact pressure by a spring or the like. The configuration is such that the toner image on the photosensitive drum is transferred onto the paper when the paper passes through the transfer portion (nip portion) formed between them.

Further, as a conventional image forming apparatus, there is one disclosed in, for example, JP-A-6-27832 and JP-A-6-317994. The image forming apparatus disclosed in Japanese Patent Application Laid-Open No. 6-27832 discloses a photosensitive drum carrying a toner image, an intermediate transfer fixing belt suspended by a heating roll, a driving roll and a transfer roll, and a photosensitive drum. The spring is provided with a spring which is urged away from the main body. In this configuration, when the driving roll is driven to rotate, the transfer roll is displaced by the tension of the intermediate transfer fixing belt, and the intermediate transfer fixing belt is pressed against the photosensitive drum. As a result, while the copying operation is stopped, the intermediate transfer fixing belt is separated from the photosensitive drum, and it is possible to prevent the toner on the photosensitive drum from adhering to the intermediate transfer fixing belt and soiling.

Further, an image forming apparatus disclosed in Japanese Patent Application Laid-Open No. 6-317994 discloses a registration sensor for detecting the leading edge and the trailing edge of a sheet and a detection sensor based on the detection result of the registration sensor.
And a cam for bringing the transfer roll into and out of the image carrier so as not to give an impact thereto. In this configuration, when the registration sensor detects the leading edge of the paper, the transfer roll is pressed against the image carrier by the rotation of the cam until the leading edge of the paper reaches the transfer site between the image carrier and the transfer roll,
The toner image on the image carrier is transferred to a sheet. When the transfer progresses and the registration sensor detects the rear end of the sheet, the transfer roll is separated from the image carrier by the rotation of the cam when the rear end passes the transfer portion. Accordingly, when the sheet is not present, the transfer roll is separated from the image carrier, so that the toner remaining on the image carrier is transferred to the transfer roll, and it is possible to prevent a back stain on the subsequent sheet. . Further, when the transfer roll is brought into contact with the image carrier, no impact is applied by the cam, so that the disturbance of the image written on the image carrier can be prevented.

However, in these apparatuses, when the paper passes between the photosensitive drum and the transfer roll, particularly when the leading edge of the paper enters between the photosensitive drum and the transfer roll,
When the trailing edge of the paper comes out of the nip portion, a shock is applied to both the photosensitive drum and the transfer roll due to the thickness difference of the paper, and as a result, the load torque of the photosensitive drum fluctuates, and the rotation speed of the photosensitive drum fluctuates. Problems arise. This problem also exists in a black-and-white printer, but in a color printer, it is a major problem in image quality such as color shift and uneven color tone.

Techniques that can solve the above problems include:
There is one disclosed in JP-A-11-52743. In the image forming apparatus shown here, as shown in FIG.
A transfer member (transfer roll) 201 that is in pressure contact with the image carrier 200 is swingably supported in a predetermined direction, and the transfer member 201 is moved in a predetermined direction in response to an external force generated when the paper advances to a transfer portion. A movable means 202 for swinging is provided.

In this configuration, since the transfer roller 201 is swingably supported in a direction parallel to the traveling direction of the sheet, when the leading end of the sheet enters the nip, and the trailing end of the sheet comes out of the nip. The occasional transient load fluctuation is absorbed by the swing of the transfer roll 201. For this reason, it is possible to prevent the rotation of the photosensitive drum and the intermediate transfer body from fluctuating, and as a result, it is possible to suppress the above-described image quality defect.

[0008]

However, the above-mentioned prior art has the following problems. That is, in the image forming apparatus disclosed in Japanese Patent Application Laid-Open No. H11-52743, as shown in FIG. 11, the transfer roll 201 is urged by a spring 203 or the like, and the movable means 202 is also constituted by a spring or the like. Therefore, when the position is initially set by a jig or the like and the position of the photosensitive drum or the intermediate transfer member is fixed, the effect of suppressing the rotation fluctuation of the photosensitive drum 200 or the like is exhibited. However, in the actual image forming apparatus, when a paper conveyance failure occurs, it is necessary to separate the transfer roll 201 from the photosensitive drum 200 or the intermediate transfer body 200 and remove the paper. Also, when performing other maintenance, it is necessary to separate the transfer roll 201 from the photosensitive drum 200 and the like. In this case, the transfer roll 201 is
When a spring or the like is also used as the movable means 202, the transfer roll 201 and the photosensitive drum 200 or the intermediate transfer body 200 are urged each time they are separated as shown in FIG.
When composed of the same support, the deviation from the initial position is relatively small even if the separation is performed, but when composed of another support, the deviation from the initial position is large, The external force generated when the paper enters the nip portion and separates from the nip portion cannot be sufficiently absorbed by the movable means 202, and the effect of suppressing the rotation fluctuation of the photosensitive drum 200 and the intermediate transfer member 200 cannot be exhibited.

In the case where the transfer roll is driven from the photosensitive drum and the intermediate transfer member using gears,
Since a gear is provided on the transfer roll, the load fluctuation of the transfer roll is directly transmitted to the photosensitive drum and the intermediate transfer body via the gear. In this case, if the position of the transfer roll changes with respect to the photosensitive drum or the intermediate transfer body when the sheet enters or leaves the nip by the movable means, the position of the gear attached to the transfer roll also changes. Assuming that the position of the photosensitive drum or the intermediate transfer member is not changed, the gear position of the transfer roll changes, thereby changing the meshing position of the gear and causing load fluctuation and the like. Therefore, not only the transfer roll rotation load fluctuation at the time of paper entry through the gears is transmitted to the photosensitive drum and the intermediate transfer body, but also rotation fluctuation such as load fluctuation due to gear meshing change is transmitted together. Will be lost.

Accordingly, an object of the present invention is to provide a transfer member which is different from a support member for supporting an image carrier such as a photoreceptor drum or an intermediate transfer member and a support member for supporting the transfer member due to paper conveyance failure or the like. Even when the paper is separated from the image carrier or the intermediate transfer member and pressed again, the impact when the paper enters the nip portion and when the paper separates from the nip portion can be sufficiently absorbed by the movable means, and a good image can be obtained. It is an object of the present invention to provide a transfer device and an image forming device that can form a sheet.

Further, another object of the present invention is to provide a method for transmitting a driving force from an image carrier or an intermediate transfer member to a transfer member to rotate the transfer member. It is an object of the present invention to provide a transfer device and an image forming apparatus capable of preventing the transfer of an image to an image carrier and an intermediate transfer member.

[0012]

According to a first aspect of the present invention, a transfer member is pressed against an image bearing member or an intermediate transfer member which rotates while an image is held on a surface thereof. In a transfer device for transferring an image from a surface of the image carrier or the intermediate transfer member to a recording medium by inserting a recording medium into a press-contact portion between the image carrier or the intermediate transfer member and the transfer member, the transfer member includes: A pressure contact unit that presses against the image carrier or the intermediate transfer body and a transfer member that swingably supports the transfer member while regulating the image carrier or the intermediate transfer body in a direction that presses and separates the image carrier or the intermediate transfer body. Movable means for oscillating the transfer member in response to an external force generated in a process of advancing to a press-contact portion between the carrier or the intermediate transfer body and the transfer member; and a pressing direction of the image carrier or the intermediate transfer body and the transfer member. Against As dynamic direction is always constant, a transfer apparatus characterized by comprising positioning means for positioning the swing direction of the transfer member.

According to a second aspect of the present invention, the pressing direction in which the image carrier or the intermediate transfer member and the transfer member are pressed against each other is such that the rotation axis of the image carrier or the intermediate transfer member and the rotation axis of the transfer member are different. 2. The transfer device according to claim 1, wherein the transfer direction is a direction connecting the two axes or a direction connecting substantially both axes.

According to a third aspect of the present invention, in the transfer apparatus according to the first aspect, the movable means includes an elastic member which supports the transfer member so as to swing in the predetermined direction. It is.

According to a fourth aspect of the present invention, there is provided the transfer apparatus according to the first aspect, wherein a swing direction of the movable means is a direction perpendicular or substantially perpendicular to the pressing direction.

According to a fifth aspect of the present invention, the transfer member includes an elastic member which presses the image carrier or the intermediate transfer member with a predetermined contact pressure. It is a transfer device of the description.

According to a sixth aspect of the present invention, there is provided an image carrier, wherein an electrostatic latent image corresponding to image information is formed, and the electrostatic latent image is developed to form a developed image. The developed image formed on the image carrier may be directly transferred to a recording medium by a transfer member pressed against the image carrier, or the developed image formed on the image carrier may be transferred via at least one intermediate transfer body. In an image forming apparatus for forming an image by transferring to a recording medium by a transfer member pressed against the intermediate transfer body, the image forming apparatus controls the transfer member in a direction in which the transfer member is pressed and separated from the image carrier or the intermediate transfer body. A pressing means for pressing against a carrier or an intermediate transfer member and the transfer member are swingably supported, and are generated in a process in which the recording medium advances to a pressing portion between the image carrier or the intermediate transfer member and the transfer member. According to external force Movable means for oscillating the transfer member, and positioning means for positioning the oscillating direction of the transfer member such that the oscillating direction of the image bearing member or the intermediate transfer member with respect to the pressure contact direction of the transfer member is always constant. An image forming apparatus comprising:

According to a seventh aspect of the present invention, the image bearing member or the intermediate transfer member and the transfer member are pressed against each other by a pressing direction of a rotation axis of the image bearing member or the intermediate transfer member and a rotation axis of the transfer member. 7. The image forming apparatus according to claim 6, wherein the direction is a direction connecting the two axes or a direction connecting substantially both axes.

According to an eighth aspect of the present invention, in the image forming apparatus according to the sixth aspect, the movable means includes an elastic member which supports the transfer member so as to swing in the predetermined direction. Device.

According to a ninth aspect of the present invention, there is provided the image forming apparatus according to the sixth aspect, wherein the swinging direction of the movable means is perpendicular or substantially perpendicular to the pressing direction.

According to a tenth aspect of the present invention, the transfer member includes an elastic member which presses the image carrier or the intermediate transfer member with a predetermined contact pressure. An image forming apparatus according to any one of the preceding claims.

According to the present invention, there is provided an image bearing member on which an electrostatic latent image corresponding to image information is formed and the electrostatic latent image is developed to form a developed image. The developed image formed on the image carrier may be directly transferred to a recording medium by a transfer member pressed against the image carrier, or the developed image formed on the image carrier may be transferred via at least one intermediate transfer body. In an image forming apparatus that forms an image by transferring an image to a recording medium by a transfer member pressed against the intermediate transfer body, the transfer member is drivingly connected to an image carrier or an intermediate transfer body using a gear, and the transfer member is connected to the transfer member. A pressure contact unit that presses against the image carrier or the intermediate transfer body and a transfer member that swingably supports the transfer member while regulating the direction in which the image carrier or the intermediate transfer body is pressed and separated from the image carrier or the intermediate transfer body. Carrier or intermediate transfer member A movable means for oscillating the transfer member in response to an external force generated in a process of advancing to the pressure contact portion of the transfer member; and a direction in which the image bearing member or the intermediate transfer member and the transfer member are slid with respect to the pressure contact direction is always constant. An image forming apparatus is provided with positioning means for positioning the transfer member in the swing direction.

According to a twelfth aspect of the present invention, there is provided the image according to the eleventh aspect, wherein the gear attached to the rotation shaft of the transfer member and the transfer member are connected by an elastic member. It is a forming device.

According to a thirteenth aspect of the present invention, the positional relationship between the gear attached to the rotating shaft of the transfer member and the gear attached to the rotating shaft of the image carrier or the intermediate transfer member is always the same. 12. The image forming apparatus according to claim 11, further comprising a positioning unit that performs positioning such that

According to a fourteenth aspect of the present invention, the pressing direction in which the image carrier or the intermediate transfer member and the transfer member are pressed against each other is such that the rotation axis of the image carrier or the intermediate transfer member and the rotation axis of the transfer member are different. 12. The image forming apparatus according to claim 11, wherein the direction is a direction connecting the two axes or a direction connecting substantially both axes.

According to a fifteenth aspect of the present invention, in the image forming apparatus according to the eleventh aspect, the movable means includes an elastic member for supporting the transfer member so as to swing in the predetermined direction. Device.

The invention according to claim 16 is the image forming apparatus according to claim 11, wherein the swing direction of the movable means is a direction perpendicular or substantially perpendicular to the pressing direction.

The invention according to claim 17 is characterized in that the transfer member is provided with an elastic member which presses the image carrier or the intermediate transfer member at a predetermined contact pressure. An image forming apparatus according to any one of the preceding claims.

According to the present invention, a plurality of the image carriers are arranged in parallel, and the developed images of different colors formed on the plurality of image carriers are transferred onto at least one intermediate transfer member. 12. The image forming apparatus according to claim 11, wherein the image is transferred onto the recording medium from the intermediate transfer body after transferring the image to the recording medium.

The invention described in claim 19 is characterized in that the plurality of image carriers and the intermediate transfer member are rotated and driven by one drive source to form a color image.
9. An image forming apparatus according to item 8.

According to a twentieth aspect of the present invention, there is provided the image forming apparatus according to the eleventh aspect, wherein a cleaner member is in contact with the transfer member.

[0032]

According to the above construction, when the support member for supporting the image carrier and the intermediate transfer member is different from the support member for supporting the transfer member, the two members repeatedly press and separate, and
Even if the position of the transfer member is likely to change, the relative position between the image carrier or the intermediate transfer member and the transfer member is regulated, so that the pressing direction and the swinging direction of the movable means are always the same. Therefore, even when the transfer roll is separated from the image bearing member or the intermediate transfer member due to a sheet conveyance failure or the like and pressed again, the impact when the sheet enters the nip portion and when the sheet separates from the nip portion is sufficiently moved by the movable member. It absorbs and can form a good image.

[0033]

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

Embodiment 1

FIG. 1 shows a tandem-type full-color printer as an image forming apparatus according to an embodiment of the present invention.

As shown in FIG. 1, this full-color printer has photosensitive drums (image carriers) 11, 21, 31 for black (K), cyan (C), yellow (Y), and magenta (M). Forming units 10, 20, having 41, 41
30, 40, and primary charging charging rolls (contact type charging devices) 12, 22, which contact these photosensitive drums 11, 21, 31, 41, respectively.
32,42 and laser optical unit (exposure device) 13,23,33,
43, a developing device 14, 24, 34, 44, and a first intermediate transfer drum (intermediate transfer member) that contacts two photosensitive members 11, 21 of the four photosensitive drums 11, 21, 31, 41. A) a second intermediate transfer drum (intermediate transfer member) 52 that contacts the photoconductor 51 and the other two photoconductors 31 and 41, and the first and second intermediate transfer drums
Third intermediate transfer drum (intermediate transfer body) contacting 51 and 52
53 and a transfer roll (transfer member) 61 that comes into contact with the third intermediate transfer drum 53 constitute a main part thereof.

The photosensitive drums 11, 21, 31, and 41 are arranged at regular intervals so as to have a common tangent plane M. The first intermediate transfer drum 51 and the second intermediate transfer drum 52 have respective rotating shafts of the photosensitive drums 11, 21, 31, 41.
They are arranged so as to be parallel to the axis and have a plane target relation with a predetermined target plane as a boundary. Further, the third intermediate transfer drum 53 is arranged so that the rotation axis is parallel to the photosensitive drums 11, 21, 31, 41.

Signals corresponding to the image information for each color are rasterized by an image processing unit (not shown) and input to the laser optical units 13, 23, 33, and 43. In the laser optical units 13, 23, 33, 43, black, cyan,
Yellow, magenta laser beam LB-K, LB-C, LB-Y, LB-M
Are modulated and the photosensitive drums of corresponding colors 11, 21, 31, 41
Is irradiated.

An image forming process for each color by a known electrophotographic method is performed around each of the photosensitive drums 11, 21, 31, and 41. First, as shown in FIG. 1, the surface of the photosensitive drums 11, 21, 31, 41 is applied to a charging roll 12, 22, 32, 42 as a contact type charging device by applying a voltage of about -1000V. , For example, to about -500V. afterwards,
Laser light units LB-K, LB- corresponding to black, cyan, yellow, and magenta are provided on the surfaces of the photosensitive drums 11, 21, 31, and 41 by laser optical units 13, 23, 33, and 43 as exposure devices. C, LB-Y, and LB-M are irradiated to form an electrostatic latent image corresponding to input image information for each color. Photoconductor drum
11, 21, 31, 41 are laser optical units 13, 23, 33, 43
When the electrostatic latent image is written, the surface potential of the image exposed portion is removed to about -100 V or less.

Further, the first and second embodiments used in this embodiment
The intermediate transfer drums 51 and 52 are cylindrical rotating bodies having a single-layer or multiple-layer surface with flexibility or elasticity, and generally have a metal core made of Fe, Al, or the like. On the metal pipe, a low-resistance elastic rubber layer (R = 10 ² to 10 ³ Ω) represented by conductive silicone rubber,
The thickness is set to about 0.1 to 10 mm. Further, the outermost surfaces of the first and second intermediate transfer drums 51 and 52 are typically made of fluororubber in which fine particles of fluororesin are dispersed with a thickness of 3 to 100 μm.
m is formed as a high release layer (ρ _V = 10 ¹¹ to 10 ¹³ Ω · cm) and bonded with a silane coupling agent-based adhesive (primer). The first and second intermediate transfer drums 51 and 52 have flexibility and elasticity of about 20 to 90 ° in JIS-A hardness.

The toner images of the respective colors formed on the photosensitive drums 11, 21, 31, 41 are firstly transferred to the transfer nip area.
About +4 applied to the cores of the second intermediate transfer drums 51 and 52
The electric field is transferred onto the first and second intermediate transfer drums 51 and 52 by a transfer voltage of about 00V. In FIG. 1, a black toner image is first transferred from a black photosensitive drum 11 onto a first intermediate transfer drum 51, and then a cyan toner image is transferred from a cyan photosensitive drum 21 to a first intermediate transfer drum 51. The black toner image previously transferred is superimposed and transferred from above. On the second intermediate transfer drum 52, first, a yellow toner image is transferred from the yellow photosensitive drum 31, and then a magenta toner image is transferred from the magenta photosensitive drum 41 first. The transferred yellow toner image is superimposed and transferred. In one embodiment according to the present invention shown in FIG. 1, the process distance from the formation of the electrostatic latent image to the transfer of the full-color toner image to the paper is different for each color. Therefore, in the embodiment of FIG. 1, since the image is written by the laser beam in the order of the black image, the cyan image, the yellow image, and the magenta image, the first intermediate transfer drum 51 and the second intermediate transfer drum 52 The order of the superimposed toner images is determined.

As described above, the first and second intermediate transfer drums 5
The toner images formed on the first and second intermediate transfer drums 53 and 52 are collectively transferred from the first intermediate transfer drum 51 to the third intermediate transfer drum 53 in the order of black and cyan. From 52, yellow and magenta are collectively transferred in this order.

The sectional configuration of the third intermediate transfer drum 53 is
The first and second intermediate transfer drums 51 and 52 are substantially the same.
0.1 to 10mm on a metal core made of e or Al
Degree low resistance elastic rubber layer (R = 10^Two~Ten^ThreeΩ) but typical
Is provided with a conductive silicone rubber or the like. Furthermore,
The outermost surface layer of the third intermediate transfer drum 53 is typically
Fluororubber with fine resin particles dispersed in a thickness of 3 to 100 μm
m high release layer (ρ _V= 10¹¹~Ten¹²Ω · cm)
With silane coupling agent-based adhesive (primer)
Glued. Hardness of the entire third intermediate transfer drum 53
Has flexibility and elasticity of about 20 to 90 ° in JIS-A hardness.
I have.

At the transfer nip portion of the first intermediate transfer drum 51, the magenta and the yellow layer previously transferred from the second intermediate transfer drum 52 are collectively transferred on the yellow layer in the order of cyan and black. A toner layer in the order of magenta, yellow, cyan, and black is formed. A transfer voltage of about +800 V is applied to the core portion of the third intermediate transfer drum 53, and the toner image on the first intermediate transfer drum 51,
The toner image on the second intermediate transfer drum 52 is transferred in a superimposed state.

On the other hand, the recording paper 62 as a recording medium is fed into a storage cassette (not shown), and forms a desired amount of paper curl at the pre-nip portion of the paper transport roll 63 and waits.

In response to a timing signal from a sequence controller (not shown), the recording paper 62 is transported from the paper transport roll 63 so that the leading edge of the paper coincides with the leading edge of the image. Enter the nip area with 61. The full-color toner image formed on the third intermediate transfer drum 53 is conveyed in the direction of the arrow while being transferred onto the recording paper 62 by a transfer voltage applied to the transfer roll 61, approximately + 2050V.

The transfer roll 61 is a flexible or elastic cylindrical rotating body, and receives a driving force from the third intermediate transfer drum 53 via a gear, or the third intermediate transfer drum 53 It is rotated by the following driven by the frictional driving force.

The toner image transferred onto the recording paper 62 by the transfer roll 61 is conveyed in the direction of the arrow, and
And is discharged outside the apparatus. The transfer roll 61 is cleaned by a cleaner (not shown) on the toner adhered to or transferred to the surface while rotating in the rotation direction, and is prepared for the next transfer step.

As described above, in FIG. 1, which is an embodiment of the present invention, the photosensitive drums 11, 21, and 21 for each color are shown.
The black photosensitive drum 11 and the cyan photosensitive drum 21 are in contact with or close to the first intermediate transfer drum 51. Here, primary transfer from the photosensitive drums 11 and 21 to the first intermediate transfer drum 51 is performed. Further, the yellow photoconductor drum 31 and the magenta photoconductor drum 41 are in contact with or close to the second intermediate transfer drum 52. Here, primary transfer from the photosensitive drums 31 and 41 to the second intermediate transfer drum 52 is performed. The first intermediate transfer drum 51 and the second intermediate transfer drum 52 have a plane-symmetric relationship parallel to the axis of each of the photoconductor drums 11 and 21 and a predetermined symmetry plane as a boundary.

Further, the third intermediate transfer drum 53
The first intermediate transfer drum 51 and the second intermediate transfer drum 52 are disposed in contact with or close to a boundary position that is symmetrical with respect to the positional relationship between the intermediate transfer drum 51 and the second intermediate transfer drum 52. The secondary transfer to the third intermediate transfer drum 53 is performed.

Finally, tertiary transfer from the third intermediate transfer drum 53 to the recording paper 62 conveyed by the transfer roll 61 is performed, and a final full-color toner image is formed.

FIG. 2 shows means for pressing the transfer member. The rotating shaft 53a of the third intermediate transfer drum 53 is, as shown in FIG.
Front frame 71 of full-color printer (support)
The transfer roller 61 is pressed against the third intermediate transfer drum 53 by pressing means 73 in a state where the position is fixed. The pressing means 73 includes a support 74 that supports the transfer roll 61 rotatably and movably in a direction of pressing and separating from the third intermediate transfer drum 53. The support 74 includes a front support plate portion 75 that supports the front side of the transfer roll 61, a rear support plate portion 76 that supports the rear side of the transfer roll 61, and a front support plate portion 75 and a rear support plate. And a connecting plate 77 for connecting the plate 76. Support 74
The front side support plate portion 75 and the rear side support plate portion 76
A long hole 78 having an open end on the side of the intermediate transfer drum 53 is formed, and the open end 78a of the long hole 78 guides the rotating shaft 53a of the third intermediate transfer drum 53. A recess 79 for positioning the rotary shaft 53a of the third intermediate transfer drum 53 is provided on the back side of the tapered portion 78a. Also, the elongated hole of the support 74
A rotation shaft 61a of the transfer roll 61 is rotatably supported inside 78, and the rotation shaft 61a of the transfer roll 61 is also supported.
A spring 80 for urging a to the third intermediate transfer drum 53 side is provided.

Here, an intermediate transfer member is used as an example, but the intermediate transfer member may be a photosensitive drum. In this configuration, even if the third intermediate transfer drum 53 is separated from the transfer roll 61 and pressed again, the third intermediate transfer drum 53
Since the pressing direction of the transfer roller 61 and the transfer roller 61 is always restricted by the elongated hole 78 of the support 74 in the direction between the two axes, the pressing direction does not vary every time it is separated. For example, even if the positional relationship between the supports is shifted as shown in FIG. 11, the configuration of the present invention can always apply pressure in the direction between both axes. Further, since the position of the shaft 53a of the third intermediate transfer drum 53 is determined by the recess 79 provided in the elongated hole 78, a desired pressure can be applied by the spring constant of the spring 80.

FIG. 3 shows the movable means of the transfer member. Here, the details of the press contact means in FIG. 2 are omitted. First,
The positioning pins 81 and 8 are respectively attached to the front-side support plate portion 75 and the rear-side support plate portion 76 of the first support 74 including the press-contact means 73.
2 is adopted. At this time, the two positioning pins 81 and 82 are arranged such that a straight line connecting the two pins is perpendicular or substantially perpendicular to the pressing direction. In the present invention, the positioning pins 81 and 82 are inserted into the arc-shaped elongated holes 86 provided in the front support plate 84 and the rear support plate 85 of the second support 83 supporting the transfer roll 61. It is configured to be. With this configuration, the direction in which the transfer member swings when the sheet enters or leaves can always be perpendicular or substantially perpendicular to the pressing direction. Where two pins
By biasing 81 and 82 by the swinging spring 87, the position is determined in a balanced manner at any position of the arc-shaped long hole 86 centered on the shaft 53a of the third intermediate transfer drum 53. That is, the oscillating position of the transfer roll 61 becomes an arbitrary arc shape centered on the axis of the third intermediate transfer drum 53 and varies in the process of repeatedly pressing and separating, but the pressing direction and the oscillating direction are different. Since the relationship is always the same, the rotation fluctuation of the third intermediate transfer drum 53 due to the external force at the time of entering and leaving the sheet always exerts a sufficient suppressing effect. The second support 83
Is rotatable in the direction of the arrow around a pivot 88 provided on both support plate portions 84 and 85 of the second support 83, and is used when paper jam occurs or the like. The transfer roll 61 is separated from the third intermediate transfer drum 53 so that the recording paper 62 having a paper jam can be easily removed.

FIG. 4 illustrates the arc-shaped long hole shown in FIG. Although the positioning pins 81 and 82 provided on the first support 74 shown in FIG. 3 move the arc-shaped long holes 86, the positioning pins 81 and 82 82 is pressed against the outer peripheral side of the arc-shaped elongated hole 86. Therefore, the arc-shaped elongated hole 86 is in contact with the outer peripheral side.
Will work. If the frictional force due to the contact is large, the transfer roll 61 becomes difficult to move when an external force such as a sheet entering or leaving occurs, and the third intermediate transfer drum 53
Cannot sufficiently exhibit the rotation fluctuation suppressing effect.
As a countermeasure, it is possible to prevent the decrease in the suppression effect by making the inside of the arc-shaped long hole 86 slippery by processing with Teflon (registered trademark) 90 or the like, but the rolling of the bearing 91 etc. can be prevented. It is desirable to provide a mechanism.

FIG. 6 shows the rotation fluctuation of the third intermediate transfer drum 53 according to the structure of the present invention. First, in the conventional example, since the movable direction and the pressing direction are not uniquely determined, if the third intermediate transfer drum 53 and the transfer roll 61 are separated and pressed several times, as shown in FIG. In addition, a large impulse fluctuation occurs in the rotation fluctuation of the third intermediate transfer drum 53 due to the external force due to the paper entry. However, by adopting the configuration of the present invention, even if separation and pressure contact are repeated, as shown in FIG.
It has become possible to always maintain stable rotation.

Embodiment 2 FIG. 6 shows a color printer using an intermediate transfer belt to which an image forming apparatus according to Embodiment 2 of the present invention is applied. The color printer includes a belt-shaped intermediate transfer member 105 stretched by a plurality of rolls 101 to 104 and a photosensitive drum 10.
6 is provided. Here, the image forming unit 107 is an exposure unit 10 that performs exposure with a laser beam modulated based on K, Y, M, and C image signals.
8 to form an electrostatic latent image, and arrange developing units having K, Y, M, and C toners at 90-degree intervals, rotate at the time of development, and apply toner corresponding to each color to the photosensitive drum. A rotary developing device 109 for supplying a visible image to the surface is provided. The transfer roll 110 here comes into pressure contact with the intermediate transfer belt 105. However, it can be basically considered that the intermediate transfer drum 53 in FIG. 2 is replaced with the backup roll 103 in FIG. The operation of the present invention is similar.

Third Embodiment FIG. 7 shows another tandem-type color printer to which an image forming apparatus according to a third embodiment of the present invention is applied. In this method, the image forming unit 122 including the photosensitive drum 121 is the same as that shown in FIG.
The visible image formed on the surface of the photosensitive drum 121 is transferred to the intermediate transfer belt 123, and the respective images of K, Y, M, and C are formed on the intermediate transfer belt 123, and are collectively transferred by the transfer roll 124. Thus, a color image is formed on the paper 125. The configuration and operation of the present invention used here are the same as those of the intermediate transfer belt of FIG.

Fourth Embodiment FIG. 8 shows a transfer device according to a fourth embodiment of the present invention, and the same parts as those in the above embodiment are denoted by the same reference numerals.

FIG. 8 shows a structure in which the transfer roller 61 is driven to rotate by transmitting the driving force from the intermediate transfer drum 53 by the gear 130. When the transfer roll 61 is always in contact with the intermediate transfer drum 53 without being separated during the operation of the printer, since the residual toner of the intermediate transfer drum 53 adheres thereto, as shown in FIG. May be provided. In this case, the transfer roller 61 does not rotate or does not rotate at a desired speed due to the load of the cleaner 131. In order to prevent such a situation, the transfer roll 61 may be forcibly rotated by using the gear 130 or the like in some cases. But,
In the case of such a configuration, since the external force due to the entry and detachment of the sheet propagates through the gear 130 to the intermediate transfer drum 53, the rotation fluctuation of the intermediate transfer drum 53 occurs more greatly than when the gear 130 is not used. I will. Further, when the movable means or the like in the present invention is used, the meshing of the gear 130 changes due to the swinging, and a large impulse fluctuation occurs. Here, a transfer roll as shown in FIG.
By coupling the gear 130 and the gear 130 attached to the second support 83 supporting the transfer roll 61 by an elastic coupling member 132, it is possible to reduce the above-described problem of external force propagation and the influence of the change in meshing of the gear 130. it can. In the configuration of FIG. 8, the gear 130 attached to the second support 83 meshes with the gear 130 of the intermediate transfer drum 53, but the elastic coupling member 132 is deformed even if the paper enters or leaves and the transfer member swings. Gear 13
0 is not rocked. Also, the transfer roll 61
The transmission of the rotation fluctuation caused by the elastic member 132 can be reduced by twisting the elastic member 132. When the transfer roll 61 is separated, the transfer roll 61 is largely displaced by the pressing means 73, so that the coupling between the elastic coupling member 132 and the transfer roll 61 is released. Here, the transfer roll 61 by the elastic coupling member 132 is used.
The connection and release of the gear 130 and the gear 130 are performed by rotating a rotating body 133 having a taper. The pressing force of the rotating body 133 having a taper is configured to be absorbed by a spring 134 interposed between the elastic coupling member 132 and the gear 130.

Fifth Embodiment FIG. 10 shows a transfer roll, an intermediate transfer member, and four photosensitive members.
1 shows a color printer to which an image forming apparatus according to an embodiment of the present invention driven by two driving sources is applied. In this printer configuration, four photosensitive drums, two first and second intermediate transfer drums, one third intermediate transfer drum, and a transfer roll are connected by a gear train, and driven by one motor. ing. The motor shaft / gear 151 of the motor 150 is connected to a third intermediate transfer drum via two idle gears 152 and 153.
Third intermediate transfer drum gear 154 for rotating and driving 53
Is engaged. This third intermediate transfer drum gear 154
The transfer roll for rotating the transfer roll 61
A gear 155 and first and second intermediate transfer drum gears 15 for rotationally driving the first and second intermediate transfer drums 51 and 52.
6,157 is engaged. Further, the first and second intermediate transfer drum gears 156 and 157 are provided with photosensitive drums 11, 21, 31, and 41, respectively.
Are engaged with first, second, third, and fourth photosensitive drum gears 158, 159, 160, and 161 for rotationally driving the photosensitive drum gears.

In such a low-cost driving method,
Rotational fluctuations are propagated to all three intermediate transfer drums and all four photosensitive drums due to the entry and detachment of the sheet. For this reason, it is not preferable that an external force due to the entry and detachment of the sheet is transmitted to the gear train. Even in such a configuration, if the transfer member supporting method and the gear mounting method of the present invention shown in FIG. 8 are applied, it is possible to reduce rotation fluctuation due to external force.

[0063]

As described above, according to the present invention, the positional relationship between the image bearing member and the intermediate transfer member and the transfer member and the pressing direction are regulated, and the transfer member can be swung in a predetermined direction. And the transfer member is swung in a predetermined direction in accordance with an external force. Therefore, even if the transfer member is repeatedly separated from the image carrier or the intermediate transfer member, the rotation speed of the image carrier or the intermediate transfer member is maintained. Fluctuations can be well absorbed and a good image free of image defects can always be obtained.

[Brief description of the drawings]

FIG. 1 is a configuration diagram illustrating a color printer as an image forming apparatus to which a transfer device according to a first embodiment of the present invention is applied.

FIG. 2 is a perspective configuration diagram illustrating a pressure contact unit of the transfer device according to the first embodiment of the present invention.

FIG. 3 is a perspective view showing a movable unit of the transfer device according to the first embodiment of the present invention.

FIG. 4 is a perspective configuration diagram illustrating a modification of the movable unit of the transfer device according to the first embodiment of the present invention.

FIG. 5 is a waveform chart showing the effects of the transfer device according to the first embodiment of the present invention and the effect of the conventional device, respectively.

FIG. 6 is a configuration diagram illustrating a color printer as an image forming apparatus to which the transfer device according to the second embodiment of the present invention is applied.

FIG. 7 is a configuration diagram illustrating a color printer as an image forming apparatus to which the transfer device according to the third embodiment of the present invention is applied.

FIG. 8 is a configuration diagram illustrating a transfer device according to a fourth embodiment of the present invention.

FIG. 9 is a configuration diagram showing a cleaner for a transfer roll.

FIG. 10 is a configuration diagram illustrating a color printer as an image forming apparatus to which a transfer device according to a fifth embodiment of the present invention is applied, and a driving system thereof.

FIG. 11 is a configuration diagram showing a conventional transfer device.

[Explanation of symbols]

53: Third intermediate transfer drum, 53a: Rotary axis of third intermediate transfer drum, 61: Transfer roll, 61a: Rotary axis of transfer roll, 71: Front side frame (support), 72: Rear side frame ( Support: 73; press-contact means; 74: support; 75: front-side support plate; 76: rear-side support plate; 78: elongated hole;
0: Spring for pressing, 81, 82: Positioning pin (positioning means), 83: Second support, 84: Front side support plate, 85: Rear side support plate, 86: Arc-shaped long hole ( Positioning means), 87: swing spring.

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Takeshi Noguchi 430 Nakai-cho, Ashigami-gun, Kanagawa Prefecture Green Tech Nakai Fuji Xerox Co., Ltd. F-term (reference) 2H030 AA01 AB02 AD16 BB42 BB43 BB46 BB53 2H032 AA05 AA14 AA15 BA07 BA19 BA23 BA30

Claims (20)

[Claims] 1. A transfer member is pressed against an image carrier or an intermediate transfer member which rotates while holding an image on its surface, and a recording medium is inserted through a pressure contact portion between the image carrier or the intermediate transfer member and the transfer member. Thereby, in a transfer device that transfers an image from a surface of the image carrier or the intermediate transfer body to a recording medium, the image carrier is controlled while the transfer member is pressed and separated from the image carrier or the intermediate transfer body. Or, a pressing means for pressing against the intermediate transfer member, the transfer member is swingably supported, and an external force generated in a process in which the recording medium advances to a pressing portion of the image bearing member or the intermediate transfer member and the transfer member. A movable means for oscillating the transfer member in response thereto, and positioning the oscillating direction of the transfer member such that the oscillating direction of the transfer member against the image carrier or the intermediate transfer member is always constant. Rank A transfer device comprising a positioning means. 2. A direction in which the image carrier or the intermediate transfer member and the transfer member are pressed against each other, the direction in which the rotation axis of the image carrier or the intermediate transfer member is connected to the rotation axis of the transfer member, or substantially both axes. 2. A direction connecting between the two.
The transfer device as described in the above. 3. The transfer apparatus according to claim 1, wherein the movable unit includes an elastic member that supports the transfer member so as to swing in the predetermined direction. 4. The transfer device according to claim 1, wherein a swing direction of the movable means is a direction perpendicular or substantially perpendicular to the pressing direction. 5. The transfer device according to claim 1, wherein the transfer member includes an elastic member that presses the image carrier or the intermediate transfer member with a predetermined contact pressure. 6. An image carrier on which an electrostatic latent image corresponding to image information is formed and the electrostatic latent image is developed to form a developed image, wherein the developed image formed on the image carrier is provided. Transferring directly to a recording medium by a transfer member pressed against the image carrier, or pressing a developed image formed on the image carrier against the intermediate transfer body via at least one intermediate transfer body In an image forming apparatus that forms an image by transferring an image to a recording medium by a member, the transfer member is pressed against the image carrier or the intermediate transfer member while regulating the transfer member in the direction of pressing or separating from the image carrier or the intermediate transfer member. Pressing means, and the transfer member is swingably supported, and the transfer member is moved in accordance with an external force generated in a process in which the recording medium advances to a pressure contact portion between the image carrier or the intermediate transfer body and the transfer member. Movable to swing Means, and positioning means for positioning the swing direction of the transfer member so that the swing direction of the image carrier or the intermediate transfer body and the transfer member against the pressure contact direction is always constant. Image forming device. 7. A pressing direction in which the image carrier or the intermediate transfer member is pressed against the transfer member is a direction connecting the rotation axis of the image carrier or the intermediate transfer member and the rotation axis of the transfer member, or substantially both axes. 7. A direction connecting the two.
The image forming apparatus as described in the above. 8. The image forming apparatus according to claim 6, wherein the movable unit includes an elastic member that supports the transfer member so as to swing in the predetermined direction. 9. An image forming apparatus according to claim 6, wherein a swing direction of said movable means is a direction perpendicular or substantially perpendicular to said pressing direction. 10. The image forming apparatus according to claim 6, wherein the transfer member includes an elastic member that presses the image carrier or the intermediate transfer member with a predetermined contact pressure. 11. An image forming apparatus, comprising: an image carrier on which an electrostatic latent image corresponding to image information is formed and the electrostatic latent image is developed to form a developed image; A direct transfer to a recording medium by a transfer member pressed against the image carrier, or a developed image formed on the image carrier,
In an image forming apparatus for forming an image by transferring to a recording medium by a transfer member pressed against the intermediate transfer body via at least one intermediate transfer body, the transfer member uses an image carrier or an intermediate transfer body and a gear. Drive connection
While regulating the transfer member in the direction of pressing and separating from the image carrier or the intermediate transfer member, a pressing means for pressing against the image carrier or the intermediate transfer member, and supporting the transfer member in a swingable manner,
A movable unit that swings the transfer member in accordance with an external force generated in a process in which the recording medium advances to a pressure contact portion between the image carrier or the intermediate transfer body and the transfer member; and the image carrier or the intermediate transfer body. An image forming apparatus comprising: a positioning unit that positions the transfer member in a swinging direction such that a swinging direction of the transfer member with respect to a pressing direction is always constant. 12. The image forming apparatus according to claim 11, wherein the gear attached to the rotation shaft of the transfer member and the transfer member are connected by an elastic member. 13. A positioning means for positioning the gear attached to the rotation shaft of the transfer member and the gear attached to the rotation shaft of the image carrier or the intermediate transfer member so that the positional relationship is always the same. The image forming apparatus according to claim 11, further comprising: 14. A pressing direction in which the image carrier or the intermediate transfer member is pressed against the transfer member is a direction connecting the rotation axis of the image carrier or the intermediate transfer member and the rotation axis of the transfer member, or substantially both axes. The image forming apparatus according to claim 11, wherein the direction is a direction connecting the spaces. 15. The image forming apparatus according to claim 11, wherein the movable unit includes an elastic member that supports the transfer member so as to swing in the predetermined direction. 16. The image forming apparatus according to claim 11, wherein a swing direction of said movable means is a direction perpendicular or substantially perpendicular to said pressing direction. 17. The image forming apparatus according to claim 11, wherein the transfer member includes an elastic member that presses the image carrier or the intermediate transfer member with a predetermined contact pressure. 18. The method according to claim 18, wherein a plurality of the image carriers are arranged in parallel, and the developed images of different colors formed on the plurality of image carriers are transferred onto at least one intermediate transfer member, and then the intermediate transfer is performed. The image forming apparatus according to claim 11, wherein the image is transferred from a body to a recording medium at a time. 19. The image forming apparatus according to claim 18, wherein the plurality of image carriers and the intermediate transfer body are rotationally driven by a single driving source to form a color image. 20. The image forming apparatus according to claim 11, wherein a cleaner member is in contact with said transfer member.