JPH0736366Y2 - Transfer drum device in image forming apparatus - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention relates to an image forming apparatus having a transfer drum such as a color copying machine.

(Prior Art) In FIG. 3, reference numeral 1 indicates a color copying machine as an image forming apparatus. The color copying machine 1 has a document table 15, and an illumination device 16 for irradiating the document on the document table 15 with light is provided below the document table 15.

Reference numerals 19, 20, 21, and 22 denote reflection mirrors for reflecting the reflected light from the document surface. An imaging lens 25 is arranged between the reflection mirror 21 and the reflection mirror 22. Further, the reflection mirror 22 reflects the light reflected from the original surface on the exposure area of the photosensitive drum 2.
It is arranged to reflect on 2a. A color separation filter is provided between the reflection mirror 22 and the exposure area 2a of the photosensitive drum 2.
28 are arranged. The color separation filter 28 is rotated by 90 degrees so that one of blue, green and red filters can be selected according to the developing color.

The photoconductor drum 2 is configured to rotate in the clockwise direction, and around the photoconductor drum 2, a charge removing device 4, a charging device 5, a developing device 6 for black development, a developing device 7 for yellow development, A developing device 8 for magenta development, a developing device 9 for cyan development, a charge eliminating lamp 10, and a cleaning device 11 are arranged in this order in the rotational direction of the photosensitive drum 2.

Reference numeral 30 denotes a transfer drum which is rotated counterclockwise and faces the photoconductor drum 2 with a slight gap, and a transfer region is formed in this facing region.

FIG. 4 shows the structure of the transfer drum 30. Symbols in the figure
Reference numeral 31 denotes a transfer drum frame body. The transfer drum frame body 31 is formed by cylindrical side portions 31a, 31b and the side portions 31a, 31b continuously, and a belt shape connecting the side portions 31a, 31b. It is composed of the connecting portion 31c.

A flexible transfer paper support sheet 40 made of a dielectric material such as a polyester film is wound around the frame 31.

Around the transfer drum 30, as shown in FIG. 3, a charge removing charger 32, a charging charger 33, and a cleaning device.
A separation charger 34, a separation charger 35, and a separation claw 36 are arranged in this order in the rotation direction of the transfer drum 30.

The cleaning device 34 includes a cleaning roller as a cleaning member including a brush roller.
34a is provided. The cleaning device 34 is configured so as to be able to move toward and away from the transfer drum 30, and the cleaning roller 34a is provided with respect to the outer peripheral surface of the transfer drum 30.
It is designed to come into contact and separate.

In the transfer drum 30, a transfer charger 45 is arranged corresponding to the transfer area. Also cleaning device 34
Corresponding to the above, a backup roller 51 as a backup member is provided. This backup roller
The swing arm 52 is swingably supported by a swing bowl 52, and the swing arm 52 is attached to a rotary shaft 53. This swing arm 52 has a spring 54
Is attached to the swing arm by the elastic force of the spring 54.
52 is biased clockwise. The backup roller 51 is constantly pressed against the inner peripheral surface of the transfer drum 30 by this urging force.

Further, an in-drum charge eliminating charger 55 is arranged corresponding to the charge eliminating charger 32, and an in-drum charging charger 56 is arranged corresponding to the charging charger 33.

The development in the copying machine 1 is performed for each color. That is, the illumination device 16 irradiates the document on the document table 15 with light, and the reflected light from the document surface passes through the reflection mirrors 19, 20, and 21, the imaging lens 25, the reflection mirror 22, and the blue decomposition filter 28. The photosensitive drum 2 is irradiated with image-forming light, and an electrostatic latent image including a yellow component having a complementary color relationship with blue is formed on the photosensitive drum 2. Then, a yellow toner image is formed on the photosensitive drum 2 by the developing device 7 for yellow.

On the other hand, the transfer drum 30 is rotated counterclockwise, and the transfer drum 30 is charged to a predetermined potential by the action of the charging charger 56 in the drum. Then, the transfer paper is supplied from the transfer paper supply device 60 onto the transfer drum 30, and is held on the transfer drum 30. Further, the transfer drum 30 is rotated, the transfer paper is conveyed to the transfer area, and corona discharge having a polarity opposite to that of the toner image by the transfer charger 45 is applied to transfer the yellow toner image on the photosensitive drum 2 to the transfer drum. Transferred to the transfer paper on 30.

Subsequently, a magenta toner image and a cyan toner image are formed on the photoconductor drum 2 by the exposure of the green and red decomposition filters 28, the operations of the corresponding decomposition filters 28, the developing devices 8 and 9, and the yellow toner described above. The magenta toner image and the cyan toner image are respectively transferred to the transfer paper on the transfer drum 30 by the same process as the image transfer.

The transfer paper onto which the toner images of the respective colors have been transferred is separated from the transfer drum 30 by the action of the separation charger 35 and the separation claw 36 and is conveyed to the fixing device 61, where the toner images on the transfer paper are fixed, and It is discharged outside.

After the transfer operation is completed, the cleaning device 34 moves toward the transfer drum 30, and the cleaning roller 34a
Contacts the outer peripheral surface of the transfer drum 30, and the toner remaining on the transfer drum 30 is collected by the cleaning roller 34a. In such an operation, the backup roller 51 provided in the transfer drum 30 supports the portion of the transfer paper supporting sheet 40, which is in contact with the cleaning roller 34a, from the inner peripheral surface side of the transfer drum 30, and
It prevents the 40 from being deformed by the pressure contact force of the cleaning roller 34a.

(Problems to be solved by the invention) However, in the above-described conventional transfer drum device, the backup roller 51 is constantly pressed against the inner peripheral surface of the transfer drum 30 formed of the flexible sheet 40 by the elastic force of the spring 54. And since there is no adjustment of this pressure contact force,
Since the peripheral surface of the transfer drum 30 is deformed, the cleaning roller 34a cannot properly collect the toner on the transfer drum 30.

If the amount of toner collected on the transfer drum 30 is insufficient, the back surface of the transfer paper held on the transfer drum 30 may become dirty, and if a thin transfer paper is used, the image may be difficult to see. is there.

If uncollected toner is stacked on the transfer drum 30, the transfer efficiency will be reduced.

Even during the transfer operation, since the backup roller 51 is in pressure contact with the transfer paper support sheet 40, the transfer paper support sheet 40 may be deformed, resulting in transfer omission, image unevenness, or image blurring. There is.

Furthermore, in order to properly collect the toner on the transfer paper drum 30, the contact pressure of the backup roller 51 with respect to the transfer paper support sheet 40 must be uniform over the entire contact portion. For that purpose, it is necessary to manage the parts such as the swing arm 52 that support the backup roller 51 and the mounting of the backup roller 51 with high accuracy.

(Means for Solving the Problem) The present invention has been made to solve the above-mentioned conventional problems, and a cylinder is formed on both sides of the cylinder and a circumferential surface continuous with the both sides and parallel to the axis. And a transfer drum constituted by winding a flexible transfer paper support sheet around the cut drum frame so as to cover the cut portion, and a transfer operation. A cleaning member that is movable toward and away from the outer peripheral surface of the transfer drum for collecting the remaining toner on the subsequent transfer drum, and deformation of the transfer paper support sheet due to the contact of the cleaning member with the outer peripheral surface of the transfer drum. In order to prevent the contact with the inner surface of the transfer drum, it is arranged at a position facing the cleaning member,
A backup member having a length shorter than the width of the cut-off portion of the drum frame, an arm for movably supporting the backup member, and a transfer paper support sheet for the backup member which is provided on the arm and contacts the inner surfaces of both sides. A transfer drum device in an image forming apparatus, the transfer drum device including a restricting member that restricts a position with respect to.

(Operation) In this transfer drum device, the arm that supports the backup member is provided with the regulating member that comes into contact with the inner surfaces of both sides of the transfer drum. Even if it is biased, the position of the backup member with respect to the transfer paper support sheet is restricted.

Embodiment An embodiment of the present invention will be described below with reference to the drawings.

The structure is the same as that of the conventional example except for the transfer drum device in the image forming apparatus of the present invention shown in FIG. 1. Therefore, only the transfer drum device will be described for the embodiment, and the description for other configurations will be omitted. To do.

In FIG. 1, auxiliary rollers 61, 6 are provided at ends 60a, 60b of a shaft 60 of a cleaning roller 34a as a cleaning member.
1 is attached, and the auxiliary rollers 61, 61 come into contact with the outer peripheral surfaces of both side portions 31a, 31b of the frame body 31 constituting the transfer drum 30. A gear 63 is fixed to the end portion 60a, and the gear 63 meshes with a pinion 66 attached to the motor 65. A gear 67 is attached to the end portion 60b.

Reference numeral 69 indicates a collecting roller for collecting the toner on the cleaning roller 34a, and a shaft of the collecting roller 69.
A gear 71 is fixed to 70, and via an intervening gear 73,
It meshes with gear 67.

Reference numeral 75 indicates a collecting blade for collecting the toner on the collecting roller 69, and the collecting blade 75 is in contact with the peripheral surface of the collecting roller 69.

Reference numeral 77 indicates a backup roller as a backup member, and this backup roller 77 is the transfer drum 31.
It is provided inside and is arranged at a position facing the cleaning roller 34a with the transfer paper supporting sheet 40 interposed therebetween.

Both ends of a shaft 78 of the backup roller 77 are rotatably supported by respective tip portions 80a, 81a of independent arms 80, 81. Projecting pieces 80b and 81b are formed at the centers of the lower edges of the arms 80 and 81, respectively. Shafts 83c and 83d are attached to the projecting pieces 80b and 81b, and adjusting rollers 83a and 83b as restricting members are rotatably attached to the shafts 83c and 83d, respectively.

A support shaft 85 is loosely inserted into each of the base end portions 80d and 81d of the arms 80 and 81. The support shaft 85 is supported by a frame (not shown). Further, springs (not shown) are attached to the arms 80 and 81, and the adjusting rollers 83a and 83b are pressed against the insides of the side portions 31a and 31b by the elastic force of the springs.
The mounting positions of the adjusting rollers 83a and 83b are adjusted so that the backup roller 77 contacts the transfer sheet supporting sheet 40 in a state where the adjusting rollers 83a and 83b contact both side portions 31a and 31b. The contact pressure of the backup roller 77 on the transfer sheet 40 is set higher than the contact pressure of the cleaning roller 34a on the outer peripheral surface of the transfer drum 30.

Next, the operation of the transfer drum device of this embodiment will be described.

By the springs attached to the arms 80 and 81, the adjusting rollers 83a and 83b are provided on both sides 31 of the frame body 31 that constitutes the transfer drum 30.
The backup roller 77 is brought into pressure contact with a and 31b to bring the backup roller 77 into contact with the transfer paper support sheet 40 at a constant and uniform pressure.

After the transfer operation is completed, the cleaning device 34 moves toward the transfer drum 30, the cleaning roller 34a contacts the outer peripheral surface of the transfer drum 30, and the cleaning roller 34
a is driven by the motor 65, and the toner on the transfer drum 30 is collected. The toner collected on the cleaning roller 34a is electrostatically attracted to the collection roller 69 driven by the motor 65, and the toner on the collection roller 69 is scraped off by the collection blade 75, and the toner is collected in the cleaning device. Will be collected.

Since the contact pressure of the backup roller 77 is set higher than the contact pressure of the cleaning roller 34a as described above, the transfer paper support sheet 40 is not deformed by the cleaning roller 34a in the above cleaning operation.

A second embodiment will be described.

In the embodiment shown in FIG. 2, folding pieces 80c and 81c are formed on the upper edges of the arms 80 and 81, respectively.

The support shaft 85 is rotatably supported by a frame (not shown). The bases of levers 86 and 87 are fixed to the support shaft 85, and the upper ends of the free ends 86a and 87a of the lever 86 face the bent pieces 80c and 81c. A link engaging piece 86b extending upward is formed at a substantially center of an upper surface side of the lever 86, and a bent lower end 89a of a link 89 is engaged with the link engaging piece 86b. The link 89 is connected to a solenoid (not shown), and when the solenoid is excited, the link 89 is pulled up.

During the transfer operation for the transfer sheet held on the transfer drum 30, the solenoid is excited, the link 89 is pulled up against the spring (not shown), and the arms 80 and 81 are supported by the support shaft.
Ascending around 85, the backup roller 77 and the adjusting rollers 83a and 83b move away from the inner peripheral surface of the transfer drum 30.

Although the cleaning roller 34a configured by a brush roller is used as the cleaning member in the embodiment, a blade may be used instead of the cleaning roller.

(Effect of the Invention) As described above, according to the present invention, the arm supporting the backup member is provided with the regulating member that comes into contact with the inner surfaces of both sides of the transfer drum. Position of the backup member with respect to the transfer paper support sheet is restricted even if the backup member is urged to contact the transfer paper support sheet. Can be uniform.

[Brief description of drawings]

FIG. 1 is a perspective view showing a first embodiment of a transfer drum device in an image forming apparatus of the present invention, FIG. 2 is a perspective view showing the same second embodiment, and FIG. 3 is a copying machine as an image forming apparatus. FIG. 4 is a schematic view of the transfer drum. 1 ... Color copying machine as image forming apparatus, 2 ... photosensitive drum, 30 ... transfer drum, 31 ... frame body, 31a, 31b ...
… Both sides, 31c …… Coupling part, 34a …… Cleaning roller as cleaning member, 40 …… Transfer paper support sheet, 77 …… Backup roller as backup member, 83a, 83b …… Adjusting roller as regulating member

Claims (1)

[Scope of utility model registration request] Claim: What is claimed is: 1. A drum frame body, which is formed by cutting a cylinder, leaving both side portions thereof and a belt-like connecting portion which is a part of a peripheral surface which is continuous with the both side portions and which is parallel to the axis line. A transfer drum configured by winding a flexible transfer paper supporting sheet so as to cover the entire surface of the An image forming apparatus comprising: a cleaning member capable of moving in and out of contact with the transfer drum; an inner surface of the transfer drum for preventing deformation of the transfer paper support sheet due to contact of the cleaning member with an outer peripheral surface of the transfer drum. Contacting the cleaning member, the backup member having a length shorter than the width of the cut-off portion of the drum frame, which is arranged at a position facing the cleaning member, and an arm supporting the backup member so as to freely move. Transfer drum device in an image forming apparatus, which comprises: a frame; .