JPH11212370A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming device capable of preventing fog toner from being transferred on a printing paper sheet. SOLUTION: This is the image forming device provided with a transferring mechanism transferring the toner image carried on a printing area of a photoreceptor belt to a storage medium by the successive pressure by the transfer counter roller 4A with respect to a transfer blade 11b, by arranging the photoreceptor belt of a closed loop disposed as the toner image carrier 1 allowed to travel in the direction orthogonal to the feeding direction of the storage medium, while arranging the transfer counter roller 4A made possible to move back and forth in the loop forming direction of the photoreceptor belt inside the closed loop of the photoreceptor belt. In the meantime, the roll width W of the transfer counter roller 4A is formed so as to match with the width of the printing area.

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 obtained from an electrostatic latent image in a direction perpendicular to a conveying direction of a recording medium such as printing paper.

[0002]

2. Description of the Related Art In recent years, toner-type image forming apparatuses, such as laser printers, capable of forming clear images with excellent resolution have become widespread. Among such toner-type image forming apparatuses, as disclosed in Japanese Patent Application No. 7-328600, the toner image carrier is moved in a direction orthogonal to the conveyance direction of the printing paper, and the toner image is gradually reduced by one process. The orthogonal transfer type image forming apparatus that performs the transfer of the image is very suitable for promoting the miniaturization of the product due to its configuration.

[0003] A general image forming apparatus for color printing by such an orthogonal transfer system will be described below.

FIG. 4 is a configuration diagram showing a general image forming apparatus, and FIG. 5 is a schematic diagram showing a transfer mechanism of the image forming apparatus of FIG.

In FIGS. 4 and 5, 1 is a toner image carrier, 2 is a support roller, 3 is a displacement roller, 4 is a transfer opposing roller, 5 is a printing paper as a recording medium, 6 is a charger, 7
Is a developing device, 7C is a cyan developing device, 7M is a magenta developing device, 7Y is a yellow developing device, 7B is a black developing device, 8 is a cleaning device, 9 is a static eliminator, 10 is an exposure device,
Reference numeral 11 denotes a transfer plate, 12 denotes a fixing device, 13 denotes a support member, and 14 denotes a hot air blower.

[0006] The function, operation, and the like of the image forming apparatus configured as described above will be described. A toner image carrier 1 composed of a photoreceptor belt whose surface is coated with a layer of an organic photoconductive material is transported by a plurality of rollers such as a support roller 2, a displacement roller 3, and a transfer opposing roller 4 in the transport direction of the printing paper 5. The toner image is formed on the surface of the toner image carrier 1 by rotating in the direction of the arrow during image formation.

Around the toner image carrier 1, a charger 6, a developing device 7, a cleaning device 8, a static eliminator 9 and the like are arranged, and the upper portion of the toner image carrier 1 is irradiated with laser light. Exposure device 10 is arranged. As shown by an arrow in FIG. 4, when the toner image carrier 1 rotates in a direction orthogonal to the transport direction of the printing paper 5, the portion passing through the charger 6 is uniformly charged to about -600V. The exposure device 10 scans one line of the surface of the toner image carrier 1 based on the image signals of the four primary colors of cyan, magenta, yellow, and black.
Irradiate with laser light corresponding to the primary colors. When the potential of the portion irradiated with the laser beam rises to about −100 V, an electrostatic latent image divided into four for each primary color is simultaneously formed on the surface of the toner image carrier 1. When toner of four primary colors is pressed against a portion where the electrostatic latent image is formed by a developing roller (not shown), a visible image is formed on the toner image carrier 1 by toner particles having negative polarity. Toner images of each primary color appear one after another.

As shown in FIGS. 4 and 5, the developing device 7 is composed of four parts for each primary color. The developing device 7C is cyan, the developing device 7M is magenta, the developing device 7Y is yellow, and the developing device 7B Are black, cyan, magenta, yellow,
The four primary color toner layers of black are formed on a common developing roller by dividing them into four for each primary color.

As shown in FIG. 5, the orthogonal transfer type image forming apparatus is characterized in that the rotation of the toner image carrier 1 and the conveyance of the printing paper 5 are temporarily stopped during the transfer, and That is, the toner image carrier 1 is rubbed and displaced on the printing paper 5 resting on the printing paper 11 as the transfer opposing roller 4 moves. At this time, the displacement roller 3 is displaced following the movement of the transfer opposing roller 4 in order to eliminate the slack of the toner image carrier 1.

[0010] During the transfer step, the printing paper 5
If the printing paper 5 is not prevented from floating from the transfer plate 11 and the sideslip of the printing paper 5 is not prevented, there is a possibility that a printing shift may occur.

Therefore, in order to suppress the occurrence of printing deviation, a positive voltage having a polarity opposite to that of the toner image is applied to the transfer plate 11 to charge the transfer plate 11 with a positive charge. Then, the printing paper 5 is electrostatically attracted by the static electricity generated on the surface of the transfer plate 11 and is temporarily bound on the transfer plate 11. Then, the transfer plate 11 having a positive charge attracts the negatively charged toner images of the four primary colors from the surface of the toner image carrier 1 to be peeled off and transferred to the printing paper 5.

Whenever the transfer for one process is completed, the transfer opposing roller 4 passes over the printing paper 5 and moves out of the area of the printing paper 5, so that the toner image carrier 1 is separated from the printing paper 5. . Immediately before the toner image carrier 1 is separated from the printing paper 5, the application of the voltage to the transfer plate 11 has already been stopped, so that the printing paper 5 electrostatically attracted to the transfer plate 11 is released. I have. The conveyance of the printing paper 5 is started in order to proceed to the next transfer step, and the conveyance distance of the printing paper 5 is only the width of the development area (printing area) of each color of the toner image carrier 1. The printing paper 5 is intermittently sent to the fixing device 12 by the width of the developing area of each color. The fixing device 12 of the hot-air fixing system that performs fixing without contacting the printing paper 5 has a heat source and a blowing fan inside when the printing paper 5 on which the image is transferred is conveyed and placed on the support member 13. Hot air is generated by a hot air blower 14 and blown onto the printing paper 5, so that the toner particles on the surface of the printing paper 5 are melted and fixed on the printing paper 5.

Here, a transfer operation using a conventional transfer opposing roller and a transfer plate will be described with reference to FIG. FIG.
FIG. 2 is a perspective view showing a transfer opposing roller and a transfer plate constituting a conventional image forming apparatus. In FIG. 3, the toner image carrier 1, the supporting roller 2, and the displacement roller 3 are the same as those in FIGS. 4 and 5, and therefore, are denoted by the same reference numerals and description thereof will be omitted.

4B is a transfer facing roller, and 11B is a transfer plate. In FIG. 3, an area (print area) on the toner image carrier 1 to be printed on the printing paper 5 by the transfer opposing roller 4B.
Is not the entire width of the transfer opposing roller 4B, but a width of W shorter than that. The toner image in the printing area on the toner image carrier 1 is printed on the printing paper 5 by the transfer opposing roller 4B. In addition to the toner image, the toner image on the toner image carrier 1 is also printed on the toner image carrier 1 at this time. Extra toner is attached to the outside. This extra toner, so-called fog toner, is printed on the printing paper 5 by the transfer opposing roller 4 pressing the toner image carrier 1 against the transfer plate 11 over its entire width. In the color orthogonal transfer, an image for one printing sheet is transferred by several transfers, so that a black band due to fog toner is generated at a portion corresponding to a seam of printing.

[0015]

As described above, the above-mentioned conventional image forming apparatus has a problem that a black band due to fogging toner is generated at a joint portion of printing.

In this image forming apparatus, it is required to prevent the transfer of the fog toner to the printing paper.

It is an object of the present invention to provide an image forming apparatus capable of preventing transfer of fog toner to printing paper.

[0018]

In order to solve this problem, an image forming apparatus according to the present invention has a closed-loop photoreceptor belt provided as a toner image carrier, which is disposed so as to be able to run in a direction perpendicular to a recording medium feeding direction. In addition, a transfer opposing roller capable of reciprocating stroke operation in the photoreceptor belt loop forming direction is arranged in the closed loop of the photoreceptor belt, and is continuously pressed against the transfer plate by the transfer opposing roller to the printing area of the photoreceptor belt. An image forming apparatus provided with a transfer mechanism for transferring a carried toner image to a recording medium, having a configuration in which a roll width of a transfer facing roller or a width of a transfer plate is formed to a width of a print area.

Thus, an image forming apparatus capable of preventing the transfer of the fog toner to the printing paper can be obtained.

[0020]

In the image forming apparatus according to the first aspect of the present invention, a closed-loop photosensitive belt provided as a toner image carrier is disposed so as to be able to run in a direction orthogonal to a recording medium feeding direction. A transfer facing roller capable of reciprocating stroke operation in a loop forming direction of the photosensitive belt is disposed in a closed loop of the photosensitive belt, and toner carried on a printing area of the photosensitive belt by continuous pressing of a transfer plate by the transfer facing roller. An image forming apparatus having a transfer mechanism for transferring an image to a recording medium, wherein the roll width of the transfer opposing roller is formed to be the width of the print area,
As a result, both ends of the toner image carrier that are not in contact with the transfer opposing roller (portions where the fogging toner is generated) are diverted toward the roll side of the transfer opposing roller by both ends of the transfer opposing roller. Only the toner in the area is pressed by the transfer facing roller and transferred to the printing paper,
This has the effect that the toner outside the printing area does not adhere to the printing paper.

According to a second aspect of the present invention, a closed-loop photoreceptor belt provided as a toner image carrier is disposed so as to be able to run in a direction perpendicular to the feeding direction of a recording medium, and a photosensitive loop is provided in the closed loop of the photoreceptor belt. A transfer mechanism in which a transfer opposing roller capable of reciprocating stroke operation is arranged in a loop forming direction of the body belt, and a toner image carried on a printing area of the photosensitive belt is transferred onto a recording medium by continuous pressing of a transfer plate by the transfer opposing roller. Wherein the width of the transfer plate is formed to be equal to the width of the print area, and only the toner in the print area of the toner image carrier is subjected to electrostatic attraction and transfer opposition by the transfer plate. Pressing by the roller acts, the above-mentioned electrostatic attraction force and pressing do not act on the toner outside the printing area, and the toner outside the printing area adheres to the printing paper. It has the effect that it is not.

An embodiment of the present invention will be described below with reference to FIGS. (Embodiment 1) FIG. 1 is a perspective view showing a transfer mechanism constituting an image forming apparatus according to Embodiment 1 of the present invention. In FIG. 1, the toner image carrier 1, the supporting roller 2, the displacement roller 3, and the transfer plate 11B are the same as those in FIG. Reference numeral 4A denotes a transfer opposing roller whose roll width W is the width of the printing area of the toner image carrier 1.

The operation of the image forming apparatus configured as described above will be described. The movement operation of the transfer opposing roller 4A is the same as that of the related art, but the toner image carrier 1 and the printing paper 5 by the transfer opposing roller 4A (see FIGS. 4 and 5).
Is the roll width W of the transfer opposing roller 4A, that is, the width of the print area. No pressure acts on the toner outside the print area, and the toner outside the print area does not adhere to the printing paper 5. Transfer opposite roller 4A with narrow roll width W
When the roller moves while pressing the toner image carrier 1 and the printing paper 5, both end portions of the toner image carrier 1 are turned over, but this itself does not particularly affect the effect of the present embodiment.

As described above, according to the present embodiment, the roll width W of the transfer opposing roller 4A is formed to be the width of the print area, so that only the toner in the print area of the toner image carrier 1 is transferred to the transfer area. The printing paper 5 which is pressed by the roller 4A
The toner (so-called fogging toner) in an area other than the printing area of the toner image carrier 1 is prevented from adhering to the printing paper.

(Embodiment 2) FIG. 2 is a perspective view showing a transfer mechanism constituting an image forming apparatus according to Embodiment 2 of the present invention. In FIG. 2, the toner image carrier 1, the supporting roller 2, the displacement roller 3, and the transfer opposing roller 4B are the same as those in FIG. 11
A is a transfer plate whose width W is the width of the printing area of the toner image carrier 1.

The operation of the image forming apparatus configured as described above will be described. The movement operation of the transfer opposing roller 4B having a width larger than W is the same as that of the related art, but the toner image carrier 1 and the printing paper 5
The pressing range (see FIGS. 4 and 5) is the width W of the transfer plate 11A, that is, the width of the printing area, and pressing does not act on the toner outside the printing area. Further, the electrostatic attraction of the toner based on the positive voltage applied to the transfer plate 11A does not occur outside the width W, that is, in an area other than the printing area of the toner image carrier 1. Therefore, the electrostatic attraction and the pressing do not act on the toner in the area other than the printing area of the toner image carrier 1, and the toner in the area other than the printing area of the toner image carrier 1 adheres to the printing paper 5. I will not do it.

In the present embodiment, the transfer opposing roller 4B is the same as the conventional one. However, the roll width of the transfer opposing roller may be W as in the transfer opposing roller 4A in the first embodiment.

As described above, according to the present embodiment, the width W of the transfer plate 11A is formed to be equal to the width of the printing area of the toner image carrier 1. Only the electrostatic attraction force by the transfer plate 11A and the pressing by the transfer opposing roller 4B act on the toner, and the electrostatic attraction force and the pressing do not act on the toner (so-called fog toner) other than the printing area. The adhesion of the toner in the area other than the print area to the print paper 5 can be prevented. Further, if the roll width of the transfer opposing roller is set to W in addition to the width of the transfer plate 11A, it is possible to more reliably prevent the fog toner from adhering to the printing paper 5.

[0029]

As described above, according to the image forming apparatus of the first aspect of the present invention, the closed loop photosensitive belt provided as the toner image carrier can run in the direction perpendicular to the recording medium feeding direction. A transfer facing roller capable of reciprocating stroke operation in a loop forming direction of the photosensitive belt is disposed in a closed loop of the photosensitive belt, and a printing area of the photosensitive belt is continuously pressed by the transfer facing roller against a transfer plate. An image forming apparatus provided with a transfer mechanism for transferring a toner image carried on a recording medium to a transfer medium. Both end portions that are not in contact with each other (the portion where the fogging toner is generated) are diverted toward the roll side of the transfer opposing roller by both end portions of the transfer opposing roller, and the toner image carrier Only the toner in the printing area is pressed by the transfer opposing roller and transferred to the printing paper, so that the toner (so-called fogging toner) in the area other than the printing area of the toner image carrier can be prevented from adhering to the printing paper. Effects can be obtained.

According to the second aspect of the present invention, the closed-loop photoreceptor belt provided as the toner image carrier is disposed so as to be able to run in a direction orthogonal to the recording medium feeding direction, and is provided in the closed loop of the photoreceptor belt. A transfer opposing roller capable of performing a reciprocating stroke operation in the direction of loop formation of the photoreceptor belt is disposed, and a toner image carried on a printing area of the photoreceptor belt is transferred onto a recording medium by continuous pressing of the transfer opposing roller against a transfer plate. An image forming apparatus having a transfer mechanism, wherein the width of the transfer plate is formed to be the width of the print area, so that only the toner in the print area of the toner image carrier is electrostatically attracted by the transfer plate and the transfer opposing roller is used. The electrostatic force and the pressing do not act on the toner (so-called fogging toner) in the area other than the printing area of the toner image carrier, and the toner acts on the toner image carrier. Beneficial effect is obtained that it is possible to prevent adhesion to the printing paper in the toner region outside the printing area of over image bearing member.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a transfer mechanism constituting an image forming apparatus according to a first embodiment of the present invention;

FIG. 2 is a perspective view showing a transfer mechanism constituting an image forming apparatus according to a second embodiment of the present invention;

FIG. 3 is a perspective view showing a transfer opposing roller and a transfer plate constituting a conventional image forming apparatus.

FIG. 4 is a configuration diagram illustrating a general image forming apparatus.

FIG. 5 is a schematic diagram illustrating a transfer mechanism of the image forming apparatus of FIG. 4;

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 toner image carrier 2 support roller 3 displacement roller 4, 4A, 4B transfer opposing roller 5 printing paper 6 charger 7 developing device 7C cyan developing device 7M magenta developing device 7Y yellow developing device 7B black developing device 8 cleaning Device 9 Static eliminator 10 Exposure device 11, 11A, 11B Transfer plate 12 Fixing device 13 Support member 14 Hot air blower

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Masanori Goto 1006 Kadoma Kadoma, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. 72) Inventor Koji Migita 1006 Kadoma, Kazuma, Kazuma, Osaka Prefecture Inside Matsushita Electric Industrial Co., Ltd. 1006 Kadoma Kadoma, Matsushita Electric Industrial Co., Ltd. (72) Inventor: Yukinori Hara

Claims (2)

[Claims] 1. A closed-loop photoreceptor belt provided as a toner image carrier is disposed so as to be able to run in a direction orthogonal to a feeding direction of a recording medium, and a loop of the photoreceptor belt is formed in the closed loop of the photoreceptor belt. And a transfer mechanism for transferring a toner image carried on a printing area of the photoreceptor belt to a recording medium by continuous pressing of a transfer opposing roller against a transfer plate by the transfer opposing roller. An image forming apparatus, wherein a roll width of the transfer opposed roller is formed to a width of the print area. 2. A closed-loop photoreceptor belt provided as a toner image carrier is disposed so as to be able to run in a direction orthogonal to a feeding direction of a recording medium, and a loop of the photoreceptor belt is formed in the closed loop of the photoreceptor belt. And a transfer mechanism for transferring a toner image carried on a print area of the photoreceptor belt to a recording medium by continuous pressing of a transfer opposing roller against a transfer plate by the transfer opposing roller. An image forming apparatus, wherein the width of the transfer plate is formed to the width of the print area.