JPS6027028B2 - Transfer device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a transfer device applied to a transfer type electronic copying machine, and particularly to a transfer device suitable for use in a color copying machine.

In conventional color copying machines, in order to superimpose a powder image formed on a photoreceptor onto a transfer paper, the transfer paper is wrapped around a transfer roller and the transfer is performed three or four times.

This method is based on the so-called roller transfer method, and when transfer is performed multiple times, it becomes difficult for the next toner to be applied to the area where the previous toner image was located during the next transfer. A so-called hollow phenomenon occurs. Furthermore, when the transfer paper is charged and attracted to the roller, due to changes in the resistance of the transfer paper, it becomes difficult to wrap around the transfer roller when the humidity is high, and transfer failures tend to occur when the humidity is low. Therefore, the roller transfer method has many disadvantages in obtaining a final image of good quality with good color balance. There are also problems in the configuration and use of the device.

For example, in a copying machine that uses transfer paper of different paper sizes, if a small size transfer paper is used, the toner on the image drum will adhere to the area of the transfer roller where there is no paper, and then When using large-sized transfer paper, this area may cause diamond stains or uneven transfer due to non-uniformity of the transfer electric field. Therefore, cleaning means for the transfer roller is indispensable, and the operation of this cleaning means must be performed when there is no transfer paper, which is extremely troublesome. An object of the present invention is to provide a transfer device that always performs good transfer when performing transfer multiple times.

Another object of the present invention is to provide a transfer device that enables separation or superimposed transfer of images on the other side without disturbing the image after transfer. Hereinafter, the present invention will be explained in detail with reference to the drawings showing specific examples. FIG. 1 shows a side view of an embodiment of the electrophotographic machine used with the transfer device of the present invention. The light is irradiated by an illumination system (a mirror lamp 3 and a reflecting shade 2) that is integrally configured, and the reflected light is scanned by a first scanning mirror 4 and a second scanning mirror 5. The first and second scanning mirrors move at a speed ratio of 2:1 to scan the original while keeping the optical length of the first half of the lens system 6 constant. The reflected light image above is from lens 6.
After that, the light image reaches the color separation filter 7, and the light image is separated by one of the filters 7a, 7b, and 7c corresponding to the three colors [red (R), green (G), and blue (B)]. The separated and color-separated light image is transferred to a fixed third
Mirror 8 and fourth mirror 9, and dustproof sealed glass 1
0 and then an image is formed on the photosensitive drum 11. Photosensitive drum 11
is rotatably supported on a shaft 11a, rotates in the direction of the arrow with printing operation, is charged (for example, 10) by a primary charger 12, and then is irradiated with the color-separated light image while being Static electricity is removed by a static eliminator 13 having a polarity opposite to that of the primary one, and the entire surface is exposed to light uniformly by a lamp 14 to obtain a high-contrast electrostatic tank image. Photosensitive drum 11
The upper static latent image is then visualized by the developer 15.

The developing device 15 is composed of four developing devices 15a, 15b, 15c, and 15d for cyan C, magenta M, yellow Y, and black. Yellow developer 15C
). The transfer paper 16 in the cassette is fed into the machine by a paper feed roller 17, and the timing roll 18a
Take the first timing with , timing roll 18
At step b, it is sent to the entrance of the gripper 19 with even more accurate timing.

The gripper 19 closes at the position where it is removed from the cam 20, and the leading edge of the transfer paper is gripped by the gripper 19. Next, while the transfer paper 16 passes between the transfer Rorona charger 21 and the photosensitive drum 11, the developed image on the photosensitive drum is transferred onto the transfer paper.

In the case of color copying, the gripper 19 rotates three times while gripping the transfer material 16, and after the three-color transfer, the separation claws 22 and the gripper opening cam 23 operate to release the transfer material from the gripper and transfer it to the conveyor belt 24. . The transfer paper after being transferred is heat-fixed in a heat-fixing device 25 to form a 9E paper. In this device, the transfer mechanism has various features to enable good transfer.

FIG. 2 is a side view of the transfer mechanism, and FIG. 3 is a perspective view thereof. First, the conveyance guide 26 provided between the timing roller 18b and the transfer conveyance gripper has a movable structure.

This conveyance guide is provided with a fixed upper guide plate 26a, and a lower lower guide plate 26b which is rotatable around a shaft 27. When the solenoid SOL-1 is turned off, the lower guide plate 26b is moved downward by its own weight. drop down. Specifically, the transfer paper 16 fed in with the timing set by the timing roller 18b passes through the guide portion and is fed into the gripper 19. At this time, the transfer paper 16 is fed at a faster speed than the moving speed of the gripper, so for example, if the transfer paper is 40% farther away than the gripper, if you raise the gripper by about 12 columns, the transfer paper will move about 5 It penetrates into the body to the extent of skin/m and is grasped. At this time, the solenoid SOL-1 is turned off and the lower guide 26b rotates by its own weight to the position shown by the chain line, so that the lower guide no longer provides any resistance to the transfer paper. Moreover, since the lower guide is opened, the transfer paper is not held within the narrow guide 26, so that wrinkles do not occur in the transfer paper. Furthermore, a partial configuration of the gripper of this transfer device will be explained.

The gripper part 19 that grips the transfer paper needs to pass between the photoreceptor 11 and the transfer corona charger 21, and in order to pass through this gap, the overall thickness can be made thin (for example, about 8 sides). required. Construction of the gripper under such conditions poses difficulties while requiring the following conditions. That is, each grip bar requires sufficient pressing force to grip the transfer paper. Particularly when transferring multiple times, it is necessary to prevent paper misalignment. However, if the joint part of a part of the gripper is made thin, there is a risk that deformation may occur when the grip is released. In particular, if the base member of the gripper is thin and each gripper is independently pressed against the base member with a strong pressing force, the timing may not be correct when pushing up each gripper to release the gripper, and the base itself may deform and follow the movement of the gripper, making it impossible to obtain sufficient release clearance.

In the example of FIG. 3, each gripper piece 1 is attached to the common shaft 19d.
9c is provided, and the transfer paper is gripped and released by one gripper piece at the same time by rotating and pressing the shaft.

With this configuration, the gripper can be opened without fear of deforming the base member. The above-mentioned gripping mechanism is used by being attached to a chain suspended between a pair of rollers for rotation (FIG. 1), or by being attached to a rotatably supported drum.

(Figure 4). Due to the arrangement of this transfer device, the feeding force of the transfer paper after the holding mechanism is gripped and released after transfer is based on the transfer paper being attracted to the surface of the photoreceptor and the movement of the photoreceptor. Therefore, based on the movement of the photoreceptor, the feeding direction of the transfer paper is
No special means is required as long as the direction substantially coincides with the direction of the subsequent conveyance path of the transfer paper, but there are many cases where the direction does not coincide. In this case, the transfer paper released from the gripper 19 lacks stability in its conveyance, which may cause the transfer paper to stagnate and cause a jam. In the device mechanism shown in Figure 2 or Figure 4,
A conveyance roller 28 is arranged immediately before the separation position so as to properly convey the transfer paper after the gripper is released.

That is, the transfer paper 16 sent by the guide 26 is moved by the cam 20
The tip of the cam 19 is gripped by the gripper passing through the position, and after a predetermined number of transfers are completed, the protrusion of the cam 23 is set to the release position as the gripper 19 passes through the cam 23 position, and the gripper 19 releases the transfer paper 1.
6 is released and heads toward the discharge path. Before the transfer paper is released by the gripper, the static eliminator 29 is activated, and during the transfer, the transfer corona charger 21 neutralizes the charge remaining on the transfer paper, thereby preventing the transfer paper from being attracted to the first gripper. To prevent. Conveying rollers 28 and 30 provided immediately before the separating claw 22 are arranged with the gripper conveying path in between, so that the rollers enter into each other. Therefore, when paper is ejected from the transfer device,
By forming undulations in a direction parallel to the leading edge of the transfer paper 16,
To prevent the released transfer paper from sagging due to its own weight. Moreover, the back side of the transfer paper is pressed against the roller 30, and the transfer paper can apply a feeding force. The conveyance roller 28
, 30 are arranged in a staggered manner, so there is no strong imitation as in the case of vertical pressure contact, so there is less risk of disturbing the image. By forming waves in the transfer paper, the pus is strengthened in the direction of movement of the transfer paper, and easily rides on the separation claw-shaped guide.

In the example shown in FIG. 2, a suction hole 31 that rotates coaxially with the separation claw 22 further adds a conveying force to the transfer paper. In the illustrated example, while the pipe having the suction hole is rotated, the separating claws 22 are provided coaxially through a bearing material, so that they can be operated independently. As described above, the separation claw 22 reaches the solid line position when the plunger SOL-2 is operated for separation after a predetermined color image is transferred to the transfer paper. After the separation operation, the plunger SOL-2 is turned off and returned to the position shown by the broken line by the elastic force of the spring 32. In order to prevent the transfer paper from adhering to the gripper and improve transfer efficiency in humid conditions, the gripper is electrically suspended from the main body of the device.

By doing this, the weight applied to the transfer paper by the transfer corona flows out to the main body of the device via the gripper.
This prevents transfer charge from being reduced. On the other hand, as described above, neutralizing the electric charge added to the transfer corona discharger 21 on the transfer paper using the static eliminator 29 may be activated in the final rotation process when performing the transfer process multiple times. is in good condition.

For example, if it is activated before the final rotation step, the toner may fall off the transfer paper or be offset to the roller 28. Due to this static elimination, combined with the fact that the gripper is electrically insulated from the main body, adsorption of the transfer paper hardly occurs. Furthermore, it is advisable to apply a voltage to a part of the gripper to assist the transfer, and this is particularly effective in humid conditions because the transfer paper has a high degree of conductivity.

[Brief explanation of the drawing]

Fig. 1 is a side view of a specific example copying machine to which the device based on the present invention is applied, Fig. 2 is a side view of a specific example transfer device of the present invention, Fig. 3 is a perspective view of the device shown in Fig. 2, and Fig. 4 FIG. 2 is a cross-sectional view showing a side view of a transfer device according to a different embodiment of the present invention. In the figure, 16 is a transfer paper, 19 is a gripper, 21 is a corona discharger, 22 is a separating claw, and 29 is a static eliminating means. Figure 4

Claims (1)

[Claims] 1. A transfer device that transfers a toner image formed on an image carrier onto a transfer material, comprising: a transfer material conveying means that endlessly moves the same transfer material multiple times along a circulation path; A transfer corona means for transferring the toner image onto the transfer material; a separation means for separating the transfer material after the transfer process from the conveyance means; 1. A transfer device comprising: a static eliminator for removing static electricity; the static eliminator operates before a transferred transfer material is released from a transfer material conveying means by a separation means.