JPH10232565A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming device which highly increases printing speed by setting a toner-image transfer area wider than the smallest-size printing paper usable in the device. SOLUTION: The image forming device of an orthogonal transfer system transfers a toner image, held on a toner-image carrier 1 by the supply of toner from a developing unit 3, to printing paper in a direction orthogonal to the direction where the printing paper 7 is carried, and fixes the toner image transferred to the printing paper. The length of the toner-image area on the toner- image carrier 1 in the direction where the printing paper 7 is carried is equal to or longer than a printing area on the smallest-size printing paper, usable in image formation by the device, in the direction where the printing paper is carried.

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 using an orthogonal transfer system for transferring a toner image onto a print sheet in a direction perpendicular to a conveying direction of the print sheet.

[0002]

2. Description of the Related Art In recent years, toner-type image forming apparatuses capable of forming clear images with high resolution, such as laser printers, have become widespread. Among such toner-type image forming apparatuses, as proposed in Japanese Patent Application No. 7-328600, the toner image carrier is moved while moving the toner image carrier in a direction orthogonal to the printing paper conveyance direction. An orthogonal transfer type image forming apparatus that rubs on a printing paper and transfers a toner image in small steps one by one is very suitable for promoting miniaturization of a product due to its configuration.

Hereinafter, a conventional image forming apparatus using such an orthogonal transfer system will be described. FIG. 1 is a configuration diagram schematically illustrating a general image forming apparatus of the orthogonal transfer system.
FIG. 2A is a perspective view of a main part of a general image forming apparatus of the orthogonal transfer type, and FIG. 2B is a part of a fixing unit of the general image forming apparatus of the orthogonal transfer type. Perspective view, FIG.
7A to 7D are transfer process diagrams showing a transfer process in a conventional image forming apparatus of the orthogonal transfer system.

In FIGS. 1, 2 and 4, reference numeral 1 denotes a toner image carrier formed of a photosensitive belt, 2 denotes a charger, 3 denotes a developing device, 3a denotes a toner, 3b denotes a developing roller, 3c denotes a toner image, Is a cleaning device, 5 is a static eliminator, 6 is an exposure device, 7
Is the minimum size printing paper that can be used in this apparatus, 8 is a transfer opposing roller, 9a is a support roller, 9b is a displacement roller,
Reference numeral 0 denotes a transfer plate, 11 denotes a fixing device, 12 denotes a heat source, 13 denotes a reflection plate, and 14 denotes a reflection conveyance plate. A typical example of the exposure device 6 using a laser will be described.
As the exposure device 6, not only a laser but also an LED or LCD may be used.

The arrangement, operation, and the like of the image forming apparatus configured as described above will be described.

As shown in FIG. 1, a toner image carrier 1 composed of a photoreceptor belt whose surface is coated with a layer of an organic photoconductive material is stretched by a plurality of rollers in a direction perpendicular to the conveying direction of a printing paper 7. Around the toner image carrier 1, the rotation direction of the toner image carrier 1 (arrow A in FIG. 2)
In the direction (R), a cleaning device 4, a static eliminator 5, a charger 2, and a developing device 3 are arranged in this order, and an exposure device 6 for irradiating a laser beam 6 a is arranged above the toner image carrier 1. When the toner image carrier 1 is rotated in a direction perpendicular to the transport direction of the printing paper 7 (the direction perpendicular to the paper surface of FIG. 1, the printing paper transport direction X of FIG. 2A) as indicated by an arrow AR, the charger 2 is turned on. The passed portion is uniformly charged to about -600 V, and the potential of the portion irradiated with the laser beam 6a by the exposure device 6 becomes-
When the voltage rises to about 100 V, an electrostatic latent image is formed.
When the toner 3a is pressed against the portion where the electrostatic latent image is formed by the developing roller 3b, visible toner images 3c appear on the toner image carrier 1 one after another.

As shown in FIG. 1, at the time of image formation, the toner image carrier 1 is stretched in at least three directions of a supporting roller 9a, a displacement roller 9b, and a transfer opposing roller 8 in a direction orthogonal to the transport direction of the printing paper 7. Have been.

As shown in FIG. 2A, 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 7 are temporarily stopped during transfer. Then, the toner image carrier 1 is moved in the transfer direction Y of the transfer opposing roller 8.
Is displaced by being rubbed against the printing paper 7 in accordance with the movement to. At this time, the displacement roller 9b is displaced following the movement of the transfer opposing roller 8 in order to eliminate the slack of the toner image carrier 1.

Each time the transfer in one process is completed, the transfer image counter roller 8 moves over the printing paper 7 and moves out of the area of the printing paper 7, so that the toner image carrier 1
Keep away from Then, the conveyance of the printing paper 7 is started, but the conveyance distance of the printing paper 7 is only the effective transfer width M of the toner image carrier 1. The printing paper 7 is intermittently sent by the amount corresponding to the effective transfer width M to the fixing device 11 side which fixes the toner without contacting the printing paper 7.

As shown in FIG. 2B, the fixing device 11
The heat source 12 irradiates a heat ray to melt the toner particles of the image transferred onto the printing paper 7, and a reflecting plate 13 for reflecting the heat ray radiated by the heat source 12 to the printing paper 7, The toner particles are fixed in a non-contact manner by setting the reflection transport plate 14 below the fixing device 11 to improve the thermal efficiency.

Here, a method of transferring the toner image 3c to the printing paper 7 and conveying the printing paper 7 will be described with reference to FIG. 4, Y, M, C, and Bk indicate yellow, magenta, cyan, and black toner images on the toner image carrier 1, respectively.

In FIG. 4, the lines between the toner images of Y, M, C, and Bk are shown by lines, but in actuality, there is a non-contact between the toner images in the developing unit 3 due to the seal between the toners. There is a gap in the print area. However, in this description, for simplicity, it is assumed that there is no seal gap as shown in FIG.

First, the yellow toner image on the toner image carrier 1 is placed on the printing paper 7 which is fed by a paper feeding mechanism (not shown) and conveyed to the yellow transfer area of the toner image carrier 1. Is transferred (FIG. 4A). Next, the printing paper 7 is conveyed by the printing area width of one color. Then, the next magenta printing is started, and M
Is formed. The formed toner image M is transferred onto the printing paper 7 (FIG. 4B). In the next yellow area on the same printing paper 7, Y
Is transferred (FIG. 4B). Similarly, the cyan and black toner images are sequentially printed on the printing paper 7.
Developed and transferred on the top to form a composite image (FIG. 4C,
(D)). After a series of these steps, the printing paper 7 is conveyed to the fixing device 11 side, where the toner image is fixed. The next paper feed is performed after the above-described series of printing operations is completed, and printing is performed through similar steps.

[0014]

However, in the above-described conventional image forming apparatus, the transfer area of the toner image is smaller than the print area of the minimum size of the print paper which can be used in this apparatus. However, there is a problem that the printing speed is slow because only a part of the printing area of one printing sheet is printed.

In this image forming apparatus, it is required to increase the printing speed. SUMMARY OF THE INVENTION It is an object of the present invention to provide an image forming apparatus capable of setting a toner image transfer area wider than the minimum size printing paper usable in the present apparatus and increasing the printing speed.

[0016]

In order to solve this problem, an image forming apparatus according to the present invention is arranged so that a toner image carried on a toner image carrier by toner supply from a developing device is perpendicular to a conveying direction of a printing paper. An image forming apparatus of an orthogonal transfer system for transferring a toner image transferred to a printing paper in a direction and fixing the toner image transferred on the printing paper, wherein the length of the toner image area of the toner image carrier in the conveyance direction of the printing paper is determined by the present apparatus. The length of the printing area in the transport direction of the printing paper of the minimum size printing paper capable of forming an image by the above-described method is provided.

As a result, it is possible to obtain an image forming apparatus capable of setting a toner image transfer area wider than the minimum size printing paper usable in the present apparatus and increasing the printing speed.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS According to the first aspect of the present invention, a toner image carried on a toner image carrier by toner supply from a developing device is printed on a printing paper in a direction orthogonal to a conveying direction of the printing paper. An image forming apparatus of an orthogonal transfer type for transferring and fixing a toner image transferred to a print sheet, wherein a length of a toner image area of a toner image carrier in a conveying direction of the print sheet is set to a minimum value capable of forming an image with the apparatus. The size of the print area is set to be longer than the length of the print area in the transport direction of the print paper. Have.

According to a second aspect of the present invention, in the first aspect of the present invention, there is provided an exposing device for exposing the toner image carrier based on an image signal, wherein the toner image carrier comprises a photosensitive belt. The developing unit develops the toner image carrier in accordance with the exposure. An electrostatic latent image is formed on the photoreceptor belt according to the size of the printing area of the printing paper, and the electrostatic latent image is formed. Is developed and printed on the printing area of the printing paper.

According to a third aspect of the present invention, in the second aspect of the present invention, the exposure device simultaneously controls the toner image carrier based on the image signals of the four primary colors for forming an image.
Exposure is performed for the primary colors, and the developing unit arranges toners of the four primary colors to form an image, forms toner layers of the four primary colors on the same developing roller, and develops the toner image carrier. The electrostatic latent image of each color on the toner image carrier is formed according to the size of the printing area of the printing paper,
This has the effect that the toner images of each color are transferred in accordance with the printing area of the printing paper.

Hereinafter, an embodiment of the present invention will be described with reference to FIG.
This will be described with reference to FIG. (Embodiment 1) An image forming apparatus according to Embodiment 1 of the present invention has a configuration similar to that of FIGS. 1, 2A and 2B, and functions and operations of an exposure unit 6, a developing unit 3, and the like. Etc. are different.

The function, operation, and the like of the image forming apparatus configured as described above will be described with reference to FIG. FIG.
FIGS. 3A to 3D are transfer process diagrams showing a transfer process in the image forming apparatus according to the present embodiment. In FIG.
1 is a toner image carrier, 7a, 7b, 7c and 7d are the first, second, third and fourth sheets of printing paper, which is the minimum size printing paper that can be used in this apparatus. is there.

In FIG. 3, Y, M, C, and Bk represent yellow, magenta, cyan,
3 illustrates a black toner image. In FIG.
Lines between toner images of Y, M, C, and Bk are indicated by lines.
Actually, there is a gap in the non-printing area between the respective parts due to the seal between the toners in the developing device 3. However, in this description, for simplicity, it is assumed that there is no seal gap as shown in FIG.

First, on the first printing paper 7a fed by the paper feeding mechanism (not shown) and conveyed to the yellow transfer area of the toner image carrier 1, the toner image carrier 1 The yellow toner image is transferred (FIG. 3A). Next, the printing paper 7a is conveyed by the printing area width of one color. Then, printing of the next magenta (M) is started, and an M toner image is formed on the toner image carrier 1. The formed toner image M is transferred onto the printing paper 7 (FIG. 3B). At this time, the second printing paper 7b is fed by the paper feeding mechanism, and the yellow toner image is transferred to the printing paper 7b in the yellow printing area (FIG. 3).
(B)). Similarly, the cyan and black toner images are sequentially developed and transferred onto the printing paper 7a to form a composite image (FIGS. 3C and 3D). At the same time, the second, third, and fourth printing papers 7b, 7c, and 7d are conveyed, and the toner images on the toner image carrier 1 are similarly transferred (FIGS. 3C and 3D). )). After a series of these steps is completed, the printing paper 7a, 7b, 7c, 7d is conveyed to the fixing device 11 side, where the toner image is fixed.

As described above, according to the present embodiment, the toner image area of the toner image carrier 1 is set to be larger than the printing area of the printing papers 7a to 7d. The width of one line corresponding to the printing area of (1) allows simultaneous transfer of the toner image to a plurality of printing papers 7a to 7d, so that the printing speed can be increased.

[0026]

As described above, according to the image forming apparatus of the present invention, an image can be formed in one line in the printing area of the printing paper, so that the toner image can be simultaneously transferred to a plurality of printing papers. Thus, an advantageous effect that the printing speed can be increased can be obtained.

The image forming apparatus further includes an exposure device for exposing the toner image carrier based on the image signal. The toner image carrier comprises a photosensitive belt, and the developing device develops the toner image carrier according to the exposure. An electrostatic latent image is formed on the photoreceptor belt according to the size of the printing area of the printing paper, the electrostatic latent image is developed, and a toner image based on the electrostatic latent image is printed on the printing area of the printing paper. This has the advantageous effect that it can be performed.

Further, the exposure device simultaneously exposes the toner image carrier for the four primary colors based on the respective image signals of the four primary colors for forming an image, and the developing device executes the respective toners of the four primary colors for forming the image. To form toner layers for each of the four primary colors on the same developing roller, and develop the toner image carrier so that the electrostatic latent images of each color on the toner image carrier are reduced to the size of the printing area of the printing paper. Accordingly, an advantageous effect that a toner image of each color can be transferred in accordance with the printing area of the printing paper can be obtained.

[Brief description of the drawings]

FIG. 1 is a configuration diagram schematically showing a general image forming apparatus of an orthogonal transfer system.

FIG. 2A is a perspective view of a main part of a general image forming apparatus of an orthogonal transfer type, and FIG. 2B is a partial perspective view of a fixing device of a general image forming apparatus of an orthogonal transfer type.

FIG. 3A is a transfer process diagram illustrating a transfer process in the image forming apparatus according to the first embodiment. FIG. 3B is a transfer process diagram illustrating a transfer process in the image forming device according to the first embodiment. Transfer process diagram showing the transfer process in the image forming apparatus (d) Transfer process diagram showing the transfer process in the image forming device according to the first embodiment

4A is a transfer process diagram showing a transfer process in a conventional image forming apparatus of an orthogonal transfer system. FIG. 4B is a transfer process diagram showing a transfer process in a conventional image forming device of an orthogonal transfer system. (D) Transfer process diagram showing the transfer process in the conventional image forming apparatus of the orthogonal transfer system

[Explanation of symbols]

 Reference Signs List 1 toner image carrier 2 charger 3 developing device 3a toner 3b developing roller 3c toner image 4 cleaning device 5 static eliminator 6 exposure device 7 printing paper 8 transfer facing roller 9a support roller 9b displacement roller 10 transfer plate 11 fixing device 12 heat source 13 Reflector 14 Reflective transport plate

 ──────────────────────────────────────────────────の Continuing on the front page (72) Inventor Koji Migita 1006 Kazuma Kadoma, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (72) Inventor Shinichi Kizu 1006 Kadoma Kadoma Kadoma City, Osaka Matsushita Electric Industrial Co., Ltd. (72) Inventor Yusuke Shiihara 1006 Kadoma, Kazuma, Osaka Pref. Matsushita Electric Industrial Co., Ltd. (72) Inventor Masashi Ogawa 1006 Odaka, Kazuma, Kadoma, Osaka Pref. Matsushita Electric Industrial Co., Ltd. Matsushita Electric Industrial Co., Ltd.

Claims (3)

[Claims] An image forming apparatus comprising: a toner supply unit configured to transfer a toner image carried by a toner image carrier onto a printing paper in a direction perpendicular to a direction in which the printing paper is transported; and to fix the toner image transferred to the printing paper. An image forming apparatus of an orthogonal transfer system, wherein the length of the toner image area of the toner image carrier in the conveying direction of the printing paper is printed in the conveying direction of the printing paper of the minimum size printing paper capable of forming an image by the apparatus. An image forming apparatus, wherein the length of the area is equal to or longer than the length of the area. 2. An exposure device for exposing the toner image carrier based on an image signal, wherein the toner image carrier comprises a photosensitive belt, and the developing device develops the toner image carrier in accordance with the exposure. The image forming apparatus according to claim 1, wherein: 3. The exposure device according to claim 1, wherein the exposure device simultaneously controls the toner image carrier based on image signals of four primary colors for forming an image.
Exposure is performed for the primary colors, and the developing device arranges toners of the four primary colors for forming an image, forms toner layers of the four primary colors on the same developing roller, and develops the toner image carrier. The image forming apparatus according to claim 2, wherein: