JP3498536B2 - Transfer device in image forming apparatus - Google Patents

Description

Description: BACKGROUND OF THE INVENTION [0001] 1. Field of the Invention [0002] The present invention relates to an electrophotographic image forming apparatus, and more particularly to a conveying direction of a toner image obtained from an electrostatic latent image on a recording medium such as paper. The present invention relates to a transfer device in a parallel transfer type image forming apparatus in which transfer is performed in the same direction as the transfer device. 2. Description of the Related Art In recent years, toner-type image forming apparatuses capable of forming clear images with excellent resolution, such as laser printers, have become widespread. Among such toner-type image forming apparatuses, a parallel transfer type image forming apparatus in which a photoreceptor is rubbed (rubbed) in a conveying direction of a printing paper so as to transfer a toner image one color at a time is, for example, an intermediate type. Since an intermediate transfer body such as a transfer drum is not required,
Optimum for miniaturization of products. FIG. 9 is a schematic configuration diagram of a conventional parallel transfer type image forming apparatus. In FIG. 9, an elastically deformable photosensitive belt 11 whose surface is coated with an organic photoconductive material is wound in a loop by rollers 12, 13 and a transfer opposing roller 14, and can run in the direction of arrow A in the figure. And While the positions of the rollers 12 and 13 remain fixed, only the transfer opposing roller 14 is
Are included in a drive system that can move in parallel on the same level plane and rotate itself. In the running direction of the photoreceptor belt 11, a cleaning device 16 for removing residual toner after transfer,
A static eliminator 17 for erasing residual charges after transfer, and a charger 1 for uniformly charging the photosensitive belt 11 to a negative potential in preparation for transfer
5. Photoreceptor belt 1 by irradiating exposure such as laser beam
An exposing device 2 for forming an electrostatic latent image on the surface of the photoreceptor 1 and a developing means 18 are sequentially arranged. The developing unit 18 is a combination of developing units 18B, 18Y, 18M, and 18C that are divided into black, yellow, magenta, and cyan, respectively.
A color toner image of each color toner is formed on the surface of the photoreceptor belt 11 by the developing roller 18 r provided for each of C. The printing paper 7 is supplied onto the transfer plate 19 by a paper feed roller (not shown) arranged on the path on the input side of the transfer plate 19, and after the transfer, the paper is discharged on the output side path. The sheet is sent to the fixing device side by a roller (not shown). At this time, the direction in which the printing paper 7 is supplied by the paper feed roller is the same as the direction in which the photosensitive belt 11 passes over the transfer plate 19. In such a parallel transfer type transfer apparatus, when the photoreceptor belt 11 rotates in the same direction as the conveying direction of the printing paper 7, the portion passing through the charger 15 is -60.
It is uniformly charged to about 0V. The exposing unit 2 irradiates the surface of the photoreceptor belt 11 with laser light one color at a time based on the image signals of the four primary colors of cyan, magenta, yellow, and black, thereby forming an electrostatic latent image on the photoreceptor belt. 11 is formed on the surface. By contacting only the portion corresponding to the irradiated laser light in the developing units 18B to 18C with the portion where the electrostatic latent image is formed, and pressing the toner with the developing roller 18r, the toner is visible on the photosensitive belt 11. One color toner image can be formed. In the transfer operation of the toner image of one color onto the printing paper 7, after the printing paper 7 is supplied onto the transfer plate 19, the printing paper 7 is stopped and, at the same time, the running of the photosensitive belt 11 is stopped. Let it. Then, the toner image is transferred to the printing paper 7 by pressing the photosensitive belt 11 at the portion where the toner image for one color is formed while rolling the transfer opposing roller 14. When the transfer for the first color is completed, the same process is repeated for the remaining colors. The transfer by the photoreceptor belt 11 can be performed not only when the transfer opposing roller 14 moves to the right side, but also during the period when the transfer plate 19 moves to the left from the right end to the original position after the movement. is there. Then, finally, a color toner image composed of four primary colors is formed on the printing paper 7, and when the transfer of the four colors is completed, the printing paper 7 is sent out from the transfer plate 19 to the fixing device side. In the transfer device of the orthogonal transfer system, the printing area on the printing paper is divided into a plurality of areas and printing is performed. Therefore, even if the printing paper is long in the paper feeding direction, the transfer area can be accommodated. If printing is performed while giving such a feed, printing operation on long printing paper is possible. However, in the parallel transfer method in which the running direction of the photoreceptor belt 11 and the feeding direction of the printing paper 7 coincide with each other, printing can be performed only in a printing area corresponding to the upper surface of the transfer plate 19, If the length in the sheet feeding direction is longer than the transfer plate 19, transfer by one movement of the transfer opposing roller 14 cannot be performed. For example, in FIG. 9, when the printing paper 7 is of A4 size and its vertical direction is set as the paper feeding direction, even if the printing paper of A3 size is fed in the vertical direction, half the area is obtained. Can only be printed. As described above, when the transfer plate 19 corresponds to, for example, A4 size printing paper 7, printing on B5 size printing paper or the like is possible, but printing exceeding the size of the transfer plate 19 is possible. Paper cannot be transferred by one transfer operation. For this reason, in order to perform the transfer to the A3 size printing paper in one operation, for example, the transfer plate 19 is required.
Is double length in the left-right direction in FIG.
The distance between the 13 axes can be dealt with by making the length twice as long. However, if the distance between the axes of the transfer plate 19 and the rollers 12 and 13 is increased, the bulk of the transfer device itself becomes large, causing interference with the layout of the printing paper supply path and the fixing device. As a result, there are design restrictions. In addition, since the printing paper is not always used in a large format, the photoreceptor belt 1 is used in a case where the printing paper of a small size is frequently used.
In some cases, the amount of movement of one is unnecessarily long, and power is wasted. An object of the present invention is to provide a parallel transfer type image forming apparatus capable of performing printing without increasing the size of the apparatus even when the size of the printing paper exceeds the printable range using a transfer plate or a photosensitive belt. An object of the present invention is to provide a transfer device. [0014] The present invention provides a printing method for printing.
A loop-shaped photoreceptor belt capable of forming a traveling direction in parallel with the sheet conveyance direction and forming a toner image on the surface thereof by development, and a printing sheet disposed in the loop of the photoreceptor belt and set at a transfer position Along the photoreceptor belt along this
For printing a toner image will successively pressed against the surface of the printing paper
A transfer apparatus that includes a transfer opposing roller for transferring to the paper, when the length in the conveying direction of the printing paper is longer long object from the transfer region by the transfer opposing roller, the printing paper based on the size of the transfer region , The print area can be divided into a plurality of print areas, and a print image can be set in a mode in which the print image is divided into the same number and printed. In such a configuration, even if the reciprocating stroke of the transfer opposing roller and the traveling range of the photosensitive belt are limited to a certain value, when a print sheet exceeding the limited range is fed, It can be handled by setting multiple image transfer modes for one printing paper,
It is not necessary to increase the size of the transfer device in accordance with the size of the printing paper. According to the first aspect of the present invention, there is provided a loop-shaped photosensitive member capable of forming a traveling direction parallel to a conveying direction of a printing paper for printing and forming a toner image on the surface thereof by development. and body belt, sequentially pressed will toner image of the photoreceptor belt along a printing paper set in the deployed and the transfer position in the loop of the photoreceptor belt surface of the printing paper
A transfer device having a transfer opposing roller for transferring to a print sheet , and when the length of the print sheet in the transport direction is longer than the transfer area by the transfer opposing roller, printing is performed based on the size of the transfer area. It is possible to divide the print area on the paper into a plurality of parts and to set the mode to print the print image by dividing the print image into the same number. This enables the transfer operation to be performed. Hereinafter, embodiments of the present invention will be described. FIG. 1 is a schematic configuration diagram of a parallel transfer type image forming apparatus according to an embodiment of the present invention, and FIGS. 2 and 3 are schematic perspective views illustrating transfer to a printing paper. The structure of the transfer device itself is the same as that of the conventional example. In FIG. 1, a photosensitive belt 11 which can travel in the direction of arrow A is wound in a loop by rollers 12, 13 and a transfer opposing roller 14. A paper feed roller 3 for feeding the printing paper 7 is arranged on a transfer plate 19 arranged at a position along the photoreceptor belt 11. The cleaning device 1 is moved in the running direction of the photoreceptor belt 11.
6, static eliminator 17, charger 15, exposure unit 2 and black,
A developing unit 18 having developing units 18B, 18Y, 18M, and 18C that are divided into yellow, magenta, and cyan, respectively, is provided. The toner image developed by the developing device 18 is the printing paper 7 supplied on the transfer plate 19.
After the four color toner images are transferred, the printing paper 7 is transferred to the left side in FIG. 1 and sent out to the fixing device 8 side constituted by the combination of the heating roller 10 and the pressure roller 9. It is. The method of forming a color toner image on the printing paper 7 resting on the transfer plate 19 starts from the state shown in FIG. 4 at first, but in the first transfer, only the cyan toner image is transferred. . In the second transfer, as shown in FIG. 5, a magenta toner image is transferred, and the cyan and magenta toner images are superimposed on the printing paper 7. Similarly, as shown in FIG. 6, in the third transfer, a yellow toner image is transferred, and cyan, magenta, and yellow toner images are superimposed. Thereafter, as shown in FIG. 7, in the fourth transfer, a black toner image is transferred, and a color toner image is formed on the printing paper 7 by the cyan, magenta, yellow, and black toner images. In the present embodiment, the printing paper 7 is conveyed in small increments, and the toner image formation and transfer are performed separately in the conveying direction of the printing paper 7, so that the printing paper 7 can be transferred to the long printing paper 7. Printing is also possible. This is shown in FIG.
As shown in (1), it is possible to provide a print paper detection sensor 4 for detecting the print paper 7 between the transfer plate 19 and the paper feed roller 3 and to provide a system for detecting the front end and the rear end of the print paper 7. is there. As the printing paper detection sensor 4, a light transmission type photosensor or the like can be used. The length of the printing paper 7 is calculated by an arithmetic system based on the detection signals of the leading and trailing ends of the printing paper 7 and the printing is performed. The necessary number of transfers is derived for the sheet 7 and the number of transfers is automatically set. In this case, the feeding pitch of the printing paper 7 is assumed to be equal to the transfer amount per one time. Here, in the conventional example of FIG. 9, one transfer operation (photosensitive belt 1) is performed when the printing paper 7 is A4 size.
(1 is four running operations), so that the entire printing paper 7 can be transferred. On the other hand, in the present invention, even when the printing paper 7 is, for example, A3 size and is fed in the vertical direction, up to half of the leading end of the printing paper 7 is transferred as shown in FIG. The sheet is stopped on the plate 19, and first, the image is transferred by the steps shown in FIGS. Thereafter, the printing paper 7 is moved in the paper feeding direction by a distance equal to half the length of the A4 size in the vertical direction, and the printing paper 7 is similarly moved based on the image signal for the rear half.
Is transferred by the step of Thus, A
Even if the specification is set to the size of the transfer plate 19 and the travel distance of the photoreceptor belt 1 corresponding to the 4-size printing paper 7,
The transfer processing can be performed on the three-size printing paper 7 by performing the transfer operation twice. Further, not only the A3 size printing paper 7 but also a long printing paper 7 having a longer length is transferred in order on the transfer plate 19 in each printable area. Since various operations can be performed, the transfer process can be performed regardless of the length of the printing paper 7. As shown in FIG. 8, a fixing device 20 comprising a heat source 21 and a reflection plate 22 is employed.
The fixing may be performed in a non-contact manner with the toner by improving the thermal efficiency by installing the reflection plate 23 below the fixing device 20. That is, when the long printing paper 7 is conveyed and transferred in small increments, the printing paper 7 is repeatedly fed and stopped even in the fixing device. Therefore,
If the fixing device 8 is a combination of the heating roller 10 and the pressure roller 9 as shown in FIG.
Since the pressure of the print paper 7 is still applied to the printing paper 7, uneven fixing is likely to occur during the stop period. On the other hand, in the fixing device 20 shown in FIG. 8, since non-contact fixing is performed on the printing paper 7, there is an advantage that no pressure is applied, and as a result, fixing unevenness does not occur. According to the present invention, the transfer operation can be performed by dividing the print image in accordance with the length of the print paper even if the print paper is long, so that the travel distance of the photosensitive belt and the transfer opposing roller Even if the device configuration is limited by the size of the stroke, the transfer operation to long printing paper can be performed without increasing the size of the device, so there is no interference with the layout of the fixing device and other members. The image forming apparatus itself can be downsized.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic configuration diagram of a parallel transfer type image forming apparatus according to an embodiment of the present invention. FIG. 2 is a schematic perspective view showing transfer to print paper. FIG. 4 is a schematic view showing a state of transfer of cyan. FIG. 5 is a schematic view showing a state of transfer of magenta. FIG. 6 is a schematic view showing a state of transfer of yellow. FIG. 8 is a schematic diagram showing a transfer state. FIG. 8 is a schematic diagram of a fixing unit of the image forming apparatus according to the embodiment of the present invention. FIG. 9 is a schematic configuration diagram of a conventional parallel transfer type image forming apparatus. Exposure device 3 Paper feed roller 4 Print paper detection sensor 7 Print paper 8 Fixing device 11 Photoreceptor belt (toner image carrier) 12, 13 Roller 14 Transfer opposite roller 15 Charger 16 Cleaning device 17 Static eliminator 18 Developing devices 18C, 18M 18Y, 18B developing unit 18r developing roller 19 transfer plate 20 fixing unit 21 the heat source 22 reflector 23 reflector

Continued on the front page (72) Inventor Masashi Ogawa 1006 Kazuma Kadoma, Osaka Prefecture Inside Matsushita Electric Industrial Co., Ltd. Inventor Takashi Migita 1006 Kazuma, Kadoma, Osaka Prefecture Inside Matsushita Electric Industrial Co., Ltd. 4-69254 (JP, A) JP-A-6-143731 (JP, A) JP-A-5-22571 (JP, A) JP-A-8-314291 (JP, A) JP-A-63-249882 (JP, A) A) European Patent Application Publication No. 698833 (EP, A1) (58) Fields investigated (Int. Cl. ⁷ , DB name) G03G 21/14 G03G 15/01 114 G03G 15/16

Claims (1)

(57) [Claim 1] A loop-shaped photoreceptor belt capable of forming a running direction parallel to the conveying direction of printing paper for printing and forming a toner image on the surface thereof by development, and A transfer opposing roller disposed in the loop of the photoreceptor belt and sequentially pressing the photoreceptor belt against the surface of the print paper along the print paper set at the transfer position to transfer the toner image to the print paper; When the transfer device is a long object in which the length of the print sheet in the transport direction is longer than the transfer area by the transfer opposing roller, the print area on the print sheet is divided into a plurality of areas based on the size of the transfer area, and the print image is printed. A transfer mode in the image forming apparatus, wherein the mode can be set to a mode in which printing is performed by dividing the same into the same number.