JPH11265100A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming device capable of making a recording paper feed speed constant on a transfer plate. SOLUTION: As to this image forming device, a resist roller 6 and an intermediate roller 30 that feed a recording paper at a specified speed in a transfer mechanism which transfers a toner image carried on the printing area of a photoreceptor belt to the recording paper by consecutively pressing the transfer plate 4 by means of a transfer opposed roller are arranged in the recording paper feed-in direction and the recording paper feed-out direction of the transfer plate. In this case, a transfer belt 32 is provided being laid on the same level surface as the paper feed surface of both rollers 6 and 30 and which transfers a rotary driving force from the roller 6 to the roller 30.

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 for transferring a toner image on a photosensitive belt onto a recording sheet on a transfer plate.

[0002]

2. Description of the Related Art FIG. 2 is a block diagram showing a general image forming apparatus, and FIG. 3 is a schematic diagram showing a transfer mechanism of the image forming apparatus shown in FIG.

2 and 3, reference numeral 1 denotes a photoreceptor unit (OPC unit), 2 denotes a photoreceptor belt (OPC belt), 3 denotes a transfer opposing roller, 4 denotes a transfer plate, 20 denotes a recording sheet, and 21 denotes a non-contact. A fixing device, 23 is a charging device, 24 is a developing device, 24a is a toner, 24b is a developing roller, 24c is a toner image, 25 is a cleaning device, 26 is a static eliminator, 27 is an exposing device, 27a is a laser beam, and 28 is a support. Laura, 29
Is a displacement roller.

The function, operation, and the like of the image forming apparatus configured as described above will be described. The photoreceptor belt 2 has a surface coated with a layer of an organic photoconductive material. The photoreceptor belt 2 is transported by a plurality of rollers such as a support roller 28, a displacement roller 29, and a transfer opposing roller 3 in a conveying direction of the recording paper 20. (In the direction perpendicular to the sheet of FIG. 2), the toner image is formed on the surface of the photoreceptor belt 2 by rotating in the direction of arrow AR during image formation. A charger 23, a developing device 24, a cleaning device 25, a static eliminator 26, and the like are arranged around the photoreceptor belt 2, and an exposing device for irradiating a laser beam 27a on the upper portion of the photoreceptor belt 2. 27 are arranged. As shown by an arrow AR in FIG. 2, when the photoreceptor belt 2 rotates in a direction orthogonal to the direction in which the recording paper 20 is conveyed, a portion passing through the charger 23 is -6.
It is uniformly charged to about 00V. The exposing unit 27 irradiates the surface of the photoreceptor belt 2 with laser light corresponding to the four primary colors on the surface of the photoreceptor belt 2 based on image signals of the four primary colors of cyan, magenta, yellow, and black. By increasing the potential of the portion irradiated with the laser beam 27a to about -100V,
An electrostatic latent image divided into four for each primary color is simultaneously formed on the surface of the photoreceptor belt 2. When the four primary colors of toner are pressed against the portion where the electrostatic latent image is formed by the developing roller 24b, the toner images of the four primary colors become visible images on the photoreceptor belt 2 by toner particles having negative polarity. 24c appear one after another.

The characteristic of such an image forming apparatus of the orthogonal transfer type is that, as shown in FIG. 3, during the transfer, the rotation of the photosensitive belt 2 and the conveyance of the recording paper 20 are temporarily stopped, and the transfer plate 4 is stopped.
That is, the photosensitive belt 2 is displaced by being rubbed on the recording paper 20 that is stationary above with the movement of the transfer opposing roller 3. At this time, the displacement roller 29 is displaced following the movement of the transfer opposing roller 3 in order to eliminate the slack of the photosensitive belt 2.

During the transfer process, the recording paper 20 at the time of transfer is
If the recording paper 20 is not prevented from floating from the transfer plate 4 and the recording paper 20 is prevented from slipping, there is a possibility that a printing shift may occur. Therefore, in order to suppress the occurrence of printing deviation, a positive charge is generated by applying a positive voltage to the recording paper 20, and a negative voltage is applied to the transfer plate 4. Then, the positively charged recording paper 20 is electrostatically attracted to the transfer plate 4 and temporarily bound on the transfer plate 4. Then, the negatively charged four primary color toner images 24 c are drawn from the surface of the photoreceptor belt 2, peeled off, and transferred to the recording paper 20.

Each time the transfer for one process is completed, the transfer opposing roller 3 moves over the recording paper 20 and out of the area of the recording paper 20, so that the photosensitive belt 2
Peel from Immediately before the photoreceptor belt 2 is separated from the recording paper 20, the application of the voltage to the transfer plate 4 has already been stopped, so that the recording paper 20 electrostatically attracted to the transfer plate 4 has been released. . The conveyance of the recording paper 20 is started in order to proceed to the next transfer step, and the conveyance distance of the recording paper 20 is only the width of the developing area (printing area) of each color of the photosensitive belt 2. The recording paper 20 is intermittently sent to the non-contact fixing device 21 by the width of the developing area of each color.

Next, a conventional image forming apparatus including a paper conveying device for feeding the recording paper 20 to a transfer mechanism including the transfer opposing roller 3, the transfer plate 4, and the like will be described.

FIG. 4 is a schematic sectional view showing a conventional image forming apparatus including a paper conveying device for conveying a recording paper 20 from a paper feed cassette 18 to a transfer mechanism.

In FIG. 4, reference numeral 1 denotes a photosensitive unit (OP
C unit), 2 is a photoreceptor belt (OPC belt), 3
Is a transfer opposing roller, 4 is a transfer plate, 4a is a transfer surface as a paper transport surface, 5 is an OPC unit driving device, 6 is a registration roller, 7 is a registration pinch roller, 8 is an urging spring,
9 is a pinch roller holder, 10 is a horizontal guide plate, 11 is a sensor lever, 12 is a sensor board, 13 is a feed roller,
14 is a press roller, 15 is a separation roller, 16 is a separation plate holder, 17 is a paper supply plate, 18 is a paper supply cassette, 19 is a paper supply plate urging spring, 20 is a recording paper, 21 is a non-contact fixing device, 22
Is a paper discharge roller, 22a is a paper discharge pinch roller, 30 is an intermediate roller, and 31 is an intermediate pinch roller. 4, the registration roller 6 and the intermediate roller 30 are driven by different rotation driving mechanisms.

The recording paper transport operation in the image forming apparatus thus configured will be described. The recording paper 20 conveyed from the paper feed cassette 18 via the separation roller 15, the feed roller 13, and the press roller 14 is then nipped by the registration roller 6 and the registration pinch roller 7, and sent to the transfer mechanism at a predetermined speed. As can be seen from FIG.
Is determined by the rotational driving force of only the pair of the registration roller 6 and the registration pinch roller 7 sandwiching it, and then, at the intermediate position, the recording paper 20 conveyed by the predetermined distance is moved by the registration roller 6, By being sandwiched between both the pair of resist pinch rollers 7 and the pair of intermediate rollers 30 and 31, the rotation is determined by the rotational driving force of both the roller pairs 6 and 7 and the roller pairs 30 and 31.
Finally, when the recording paper 20 is conveyed by a predetermined distance and separates from the registration roller 6 and the registration pinch roller 7, it is determined by the rotational driving force of only the pair of the intermediate roller 30 and the intermediate pinch roller 31. Thus, the recording paper 20
While the transfer plate 4 is conveyed from the recording paper carry-in direction to the recording paper carry-out direction, first, only the pair of the registration roller 6 and the registration pinch roller 7 is provided.
0 and 31, and finally, only the pair of the intermediate roller 30 and the intermediate pinch roller 31 are given different rotational driving forces. Therefore, the transport speed of the recording paper 20 differs depending on the transport position. . In other words, the predetermined speed of the recording paper 20 differs depending on the position on the transfer plate 4, and is the third speed.

[0012]

As described above, in the above-described conventional image forming apparatus, the transport speed of the recording paper 20 is reduced by the transfer plate 4.
However, there is a problem that the transfer image is not constant, and the transferred image is shifted.

In this image forming apparatus, it is required that the conveying speed of the recording paper on the transfer plate is constant.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an image forming apparatus capable of keeping a recording paper conveying speed on a transfer plate constant.

[0015]

In order to solve this problem, an image forming apparatus according to the present invention provides a toner image carried on a printing area of a photosensitive belt by continuously pressing a transfer plate with a transfer opposing roller. An image forming apparatus comprising: a registration roller for feeding recording paper at a predetermined speed into a transfer mechanism for transferring to recording paper; and an intermediate roller disposed in a recording paper loading direction and a recording paper unloading direction of a transfer plate. Hung on the same level as the paper transport surface of both rollers and intermediate rollers,
A transmission belt for transmitting the rotational driving force from the registration roller to the intermediate roller is provided.

As a result, it is possible to obtain an image forming apparatus capable of keeping the recording paper conveying speed on the transfer plate constant.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In an image forming apparatus according to a first aspect of the present invention, a toner image carried on a printing area of a photoreceptor belt is recorded on recording paper by continuously pressing a transfer plate with a transfer opposing roller. An image forming apparatus in which a registration roller and an intermediate roller for feeding recording paper at a predetermined speed into a transfer mechanism for transferring are arranged in a recording paper loading direction and a recording paper unloading direction of a transfer plate, wherein the registration roller and the intermediate A transmission belt that is hung on the same level as the paper conveyance surface of both rollers and transmits the rotational driving force from the registration roller to the intermediate roller, and the peripheral speed of the intermediate roller is the peripheral speed of the transmission belt. Since the peripheral speed of the transmission belt is the same as the peripheral speed of the registration roller that rotates the transmission belt, the peripheral speed of the registration roller and the peripheral speed of the intermediate roller are the same. Having.

According to a second aspect of the present invention, in the first aspect of the present invention, the transmission belt is disposed outside the traveling range of the recording paper, and the transmission belt does not hinder the transfer operation. Has the effect that a smooth transfer operation is maintained.

Hereinafter, an embodiment of the present invention will be described with reference to FIG.
This will be described with reference to FIG. (Embodiment 1) FIG. 1A is a plan view showing the periphery of a transfer plate of an image forming apparatus according to Embodiment 1 of the present invention.
FIG. 2B is a front view of FIG.

In FIG. 1, a transfer plate 4, a transfer surface (paper transport surface) 4a, a registration roller 6, a registration pinch roller 7, a paper discharge roller 22, a paper discharge pinch roller 22a, an intermediate roller 30, and an intermediate pinch roller 31 are illustrated. 4 are the same as those in FIG. Reference numeral 32 denotes a flat belt as a transmission belt for transmitting the rotational driving force of the registration roller 6 to the intermediate roller 30, and reference numeral 33 denotes a tension pulley for maintaining the tension of the flat belt 32. The width of the recording paper 20 is a paper width W as shown in FIG. 1A, and this width W is a traveling range of the recording paper 20, and the flat belt 32 is located outside the traveling range.

The operation of the image forming apparatus configured as described above will be described. As described above, the intermediate roller 30 is a driven roller, and is driven to rotate by the registration roller 6 via the transmission belt 32. Since the transmission belt (flat belt) 32 is hung on the surface of the same level as the sheet conveying surface 4a of the rollers 6 and 30, the peripheral speed of the transmission belt 32 is the same as the peripheral speed of the registration roller 6. Further, the peripheral speed of the intermediate roller 30 is the same as the peripheral speed of the transmission belt 32, whereby the peripheral speed of the registration roller 6 and the peripheral speed of the intermediate roller 30 become the same. Therefore, conventionally, the conveying speed of the recording paper 20 is three speeds that differ depending on the position on the transfer plate 4, but in the present embodiment, the speed is constant at any position on the transfer plate 4.

As described above, according to the present embodiment, the sheet conveying surfaces 4a of both the registration roller 6 and the intermediate roller 30 are used.
And a transmission belt (flat belt) 32 for transmitting the rotational driving force from the registration roller 6 to the intermediate roller 30, so that the peripheral speed of the intermediate roller 30 is the same as the peripheral speed of the registration roller 6. Transfer plate 4
The upper recording paper transport speed can be kept constant, and the transfer image does not shift.

[0023]

As described above, according to the image forming apparatus of the first aspect of the present invention, the toner image carried on the printing area of the photosensitive belt by continuously pressing the transfer plate with the transfer opposing roller. An image forming apparatus in which a registration roller and an intermediate roller for feeding the recording paper at a predetermined speed into a transfer mechanism for transferring the recording paper to the recording paper are disposed in a recording paper loading direction and a recording paper unloading direction of the transfer plate. By providing a transmission belt that is hung on the same level as the paper transport surface of both the registration roller and the intermediate roller and that transmits the rotational driving force from the registration roller to the intermediate roller, the peripheral speed of the intermediate roller is reduced by the circumference of the transmission belt. Speed, that is, the peripheral speed of the registration roller, it is possible to keep the recording paper conveyance speed on the transfer plate constant, and to prevent the transfer image from shifting. Results can be obtained.

According to the invention described in claim 2, according to claim 1,
In the invention described in (1), since the transmission belt is disposed outside the traveling range of the recording paper, the transmission belt does not hinder the transfer operation, and thus an advantageous effect that a smooth transfer operation can be maintained can be obtained.

[Brief description of the drawings]

FIG. 1A is a plan view showing the periphery of a transfer plate of an image forming apparatus according to a first embodiment of the present invention; FIG.

FIG. 2 is a configuration diagram illustrating a general image forming apparatus.

FIG. 3 is a schematic diagram illustrating a transfer mechanism of the image forming apparatus of FIG. 2;

FIG. 4 is a schematic cross-sectional view showing a conventional image forming apparatus including a paper transport device that transports recording paper from a paper feed cassette to a transfer mechanism.

[Description of Signs] 1 Photoconductor unit (OPC unit) 2 Photoconductor belt (OPC belt) 3 Transfer opposing roller 4 Transfer plate 4a Transfer surface 5 OPC unit driving device 6 Registration roller 7 Registration pinch roller 8 Urging spring 9 Pinch roller Holder 10 Horizontal guide plate 11 Sensor lever 12 Sensor substrate 13 Feed roller 14 Holding roller 15 Separation roller 16 Separation plate holder 17 Paper feed plate 18 Paper feed cassette 19 Paper feed plate urging spring 20 Recording paper 21 Non-contact fixing device 22 Paper discharge roller 22a Discharge pinch roller 23 Charger 24 Developing device 24a Toner 24b Developing roller 24c Toner image 25 Cleaning device 26 Static eliminator 27 Exposure device 27a Laser beam 28 Supporting roller 29 Displacement roller 30 Intermediate roller 31 Intermediate pinch roller 32 Flat belt (transmission belt) ) 33 tension pulley

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Masanori Goto 1006 Kazuma Kadoma, Kadoma City, Osaka Prefecture Inside Matsushita Electric Industrial Co., Ltd. 72) Inventor Koji Mita 1006 Kazuma Kadoma, Kadoma City, Osaka Pref. Matsushita Electric Industrial Co., Ltd. (72) Inventor Tetsuya Adachi 1006 Kadoma Odama, Kadoma City, Osaka Pref. 1006 Kadoma Kadoma, Matsushita Electric Industrial Co., Ltd.

Claims (2)

[Claims] A resist for feeding a recording sheet at a predetermined speed into a transfer mechanism for transferring a toner image carried on a printing area of a photoreceptor belt onto the recording sheet by continuously pressing a transfer plate with a transfer opposing roller. An image forming apparatus in which a roller and an intermediate roller are arranged in a recording paper loading direction and a recording paper unloading direction of the transfer plate, wherein the registration roller and the intermediate roller are hung on the same level surface as a paper transport surface. An image forming apparatus comprising: a transmission belt for transmitting a rotational driving force from the registration roller to the intermediate roller. 2. The image forming apparatus according to claim 1, wherein said transmission belt is disposed outside a traveling range of the recording paper.