JPS6136775A - Transfer device - Google Patents

Abstract

PURPOSE:To prevent image disturbance due to contacting with an unfixed face by applying a voltage to parallel electrode groups to attract electrostatically a transfer material through a semiconductive film and using transfer means independently of this operation to prevent contact with an unstable transfer face. CONSTITUTION:Forms 3 are sent to a transfer area one by one with a roll 1. Three color developed images of yellow, magenta, and cyan corresponding to an original picture are formed on photosensitive drums 4a-4c, and photosensitive drums 4a-4c and electrostatically attracting belts 9 in form carrying devices 8a-8c are rotated completely synchronously. Transfer means 7a-7c are used to transfer images onto the form 3, and a color copy of yellow, magenta, and cyan is obtained. Since the transfer material is carried surely without contacting mechanically one face of the transfer material, the image disturbance due to contacting with the unfixed face is prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an improvement of a transfer device in an electrophotographic apparatus such as a copying machine.

[Background technology]

In electrophotography, a photoconductor such as a photoreceptor drum is generally charged in the dark, an original image is exposed to the photoconductor to obtain an electrostatic latent image, and this is developed. In high-speed machines, the developed image is transferred to a transfer material such as paper using a transfer means such as a roll to which a bias voltage is applied to obtain the object, but the image remains undefined until it is fixed in the next fixing process. The surface is in such an unstable state that it will come off if you touch it.

In particular, in the case of a copying machine that obtains color copies by transferring developed images of different colors onto a single sheet of paper multiple times, it is necessary to send such unfixed copies to the transfer area multiple times. Conventionally, in order to meet this requirement, the paper was held with a clipper and the paper was electrostatically attracted to a mesh-like drum, but this method resulted in image loss at the leading edge of the paper and Since the electrostatic adsorption of the paper does not have sufficient force, the rear part of the paper will be smeared, and if the unfixed surface comes into contact with other parts and is rubbed, the image will be distorted. In this case, it is possible to press and hold the unfixed surface using a star wheel, roller, or the like that has a small contact area, but even if this is done, image distortion will still occur.

[Problem that the invention seeks to solve]

This invention attempts to solve the problem of image disturbance caused by contact of the transfer material with the unfixed surface.

[Means and effects for solving the problems] This invention has the following features:
For this purpose, a transfer device is provided, which has a support conveyance body that electrostatically attracts the transfer material through a semiconductive film by applying a voltage to a group of parallel electrodes, and a separate conveyance device. By using a transfer means, it is possible to guide the transfer surface in an unstable state without mechanically touching it, thereby preventing the occurrence of image disturbance due to contact with an unfixed surface.

〔Example〕

Embodiments of the present invention will be described below based on the drawings.

Figures 1 to ÷ Figures show an embodiment of the present invention.
The case where it is applied to a color copying machine is shown. Note that color copying machines are broadly divided into 3 types in terms of the structure of their transfer devices. One is of a type having a plurality of transfer parts, and this embodiment is the latter case.

In Figure 1, (1) is a paper feed roller, (2) is a guide member that guides the paper (3), and (4a) to (4c) are each color of yellow (7), magenta (goods), and cyan (C1). The developed image of each color is sequentially transferred to the paper (3) by the photoconductor drum as a photoconductor on which the developed image of the paper (3) is formed.
The copy receiver is fixed and ejected to the tray (6). The transfer device includes transfer means (7a) to (7c) provided for each of the photoreceptor drums (4a) to (4c), and paper conveyance devices (8a) to 8a for electrostatically adsorbing and conveying the paper (2). (8c)
Equipped with.

The transfer means (7&) to (7c) may be any known transfer device such as a corotron, a bias application roller, or a brush charger, and each of the paper conveyance devices (8a) to (
8c) has the following structure.

In Fig. 2, (9) is an electrostatic adsorption belt as a supporting conveyance member for paper (2), which includes a pair of rollers (LOA), (
10b), and can be rotated in the direction of arrow A by a drive source (not shown).The electrostatic adsorption heald (9), as shown in FIGS. 8 and 4, and the semiconductive film Q2+ and the electrodes provided spaced apart from each other therebetween), (18a)..., (113
b), (18b)". The electrodes (18a), (18b) are arranged in parallel in a comb-shaped pattern.
18a)... to the reinforcing material UD side (14a),
(14a) is drawn out, and electrode Q8b).

Similarly from 08b)..., contact Q+b), (14b
)... is drawn out. The power supply frame (16a), (16b) connected to the power supply through the power supply line α51ζ supplies power only to the electrode group located in the part that requires suction among the electrode groups formed around the entire circumference, and As shown in FIG. 2, the electrostatic adsorption belt (9) is disposed along the lower side so that the adhesion force disappears when the electrostatic adsorption belt (9) passes through. And the above contacts (14a), (14a)-., (14b
), (], 4b le... and the power supply frame (16a).

(16b) tThus, the electrode α8a) passing through the power supply area.

(13a)--, (18b), (13b)..., every other power supply frame (16a), (16b)...
), a DC voltage is applied from the p-semiconducting film 07.
The paper (3) is sucked through J.

The voltage to be applied is 5000V or less, preferably 1000V or less
A range of 2000V is used. This is set from the viewpoint of dielectric breakdown and the fact that if the moisture content of the paper (3) used is low, the suction is weak and a high voltage is required from this point of view. Furthermore, regarding the semiconductive film 07J, although it is better for the volume resistivity to be low for adsorption, if it is low, the power consumption will increase, and if it is too high, it will not work as a resistor and the adsorption force will be low. It is selected in the range of 108 to 1012 Ωcm. From a mechanical standpoint, its thickness is approximately that of a 05 dragon, for example. With this configuration, the suction force can quickly rise and fall.

The paper conveyance devices (8a) to (8c) having the structure described above are very suitable for conveying paper for color copying, and are suitable for conveying paper for color copying.
3) One side, that is, the unfixed side that is still unstable, can be reliably conveyed without mechanically touching it.

As shown in Figure 1, the paper (3) is moved by the paper feed roller (1).
Therefore, each sheet is sent to five transfer areas. Photosensitive drum (4
In a) to (4c), developed images in eight colors of yellow, magenta, and cyan are created according to the original by means not shown, but the photosensitive drums (4a) to (4c) and the paper transport device (8a) The electrostatic adsorption belts (9) in ~(8c) rotate in complete synchronization, and the transfer means (7) is placed on the paper (3).
Transfer is performed one after another using a) to (7c), and yellow, magenta, and cyan toner images are superimposed to obtain a color copy. First, the paper (3) that has come out from the paper guide member (2) is transferred to the paper transport device (8a) after the developed image on the photosensitive drum (4a) is transferred onto the paper (3) by the transfer means (7a). It is electrostatically attracted and transported. Next, the sheet (3) is peeled off by a suitable peeling means, such as a belt neutralizer, a peeling claw, air blowing, etc., and sent to a transfer section consisting of a transfer means (7b), and the sheet (3) is further transferred to the next sheet conveying device (8b). will be in contact with.

When transporting the paper (3), the paper support and transport body of the paper transport device (8a) has the configuration shown in FIGS. 2 to 4, so in this embodiment, the paper is transported as shown in FIG. (3) The conveyance is performed in an upside down state, but even if it is upside down, it will be adsorbed and conveyed without falling. Also, at this time, it is inconvenient that the unfixed toner image is disturbed by the electrostatic field for attraction, but the paper (
The Coulomb force between the charge applied to the paper (3) and the charge of the toner attached to the paper (3) is so strong that it is unaffected by other electric fields, so it is not disturbed, and the experimental results also show that this is the case. It has not been. Furthermore, as mentioned above, the electrostatic adsorption belt (9), which serves as the supporting conveyor, supplies power only to the parts that require adsorption as shown in Figure 2, so the adsorption force suddenly decreases after passing the power supply area. Therefore, there is no problem with the insertion into the next transfer means (7b).

Also, JP-A-49-6218, JP-A No. 49-8953
The method described in Publication No. 7 electrostatically attracts paper to a highly insulating belt, and in this case, a high potential is required for attraction, resulting in dielectric breakdown of the photoconductor and paper falling from the belt. However, according to the above configuration, in order to support and convey the paper (3), a voltage of a different polarity is applied to every other electrode group arranged in parallel with the semiconductive film 0. This problem does not arise because the paper (3) is applied between the developed image and a transfer device, such as a corotron, which is provided separately from the developed image. The rise and fall of the suction force is extremely fast, unlike that of JP-A No. 49-6213, and therefore, the holding and peeling of the paper (3) on the conveying body is done at the processing speed of the copying machine. You can do it without any problem. Moreover, the transfer of the developed image is performed by a known means other than the conveyor as described above.

By doing so, the holding of the paper (3) and the transfer of the developed image can be controlled as desired, which is particularly useful when printing a color image.

The unfixed paper (3) sent to the transfer means (7b) is further overlaid with the developed image on the photoreceptor drum (4b) transferred by the transfer means (7b), and then Similarly, the sheet conveying device (8b) carries out conveyance, peeling, and feeding to the next transfer section.

In this way, the transfer means (7a) to (7c) are used to transfer the paper (3), and the paper (3) is conveyed without mechanically touching the unfixed transfer surface. ), yellow, magenta, and cyan toner images are superimposed on the toner image, and when this is fixed by the fixing device (5), it is possible to obtain a good color copy without image disturbance due to contact with the unfixed surface.

In the above embodiment, the case where there are a plurality of transfer sections has been explained as an example, but as mentioned above, it can also be applied to the case of a color copy system with only one transfer section, and the same effect can be applied. It is possible to eliminate image disturbances caused by contact with unfixed copies, which occurs in conventional color copying machines. That is, as shown schematically in FIG. 5, the supporting and conveying body shown in FIGS. 2 to 4 in the sheet conveying device (8) may be formed into a drum shape. In this case as well, it is possible to achieve the same purpose as in the above-mentioned embodiment, by applying voltage to the parallel electrode group and adsorbing the paper through the semiconductive film α2, and then flipping one side of the paper the necessary number of times. It is possible to transfer the developed image created by the developing means (171) by guiding it to the transfer area without mechanically touching it.

In addition, as shown in Figure 6, it can also be applied to the transfer of monochromatic developed images such as black toner, preventing the paper from lifting up without using a star wheel, etc., and without touching the unfixed surface. Can be transported.

〔Effect of the invention〕

As described above, in the electrophotographic developed image transfer device ζ, the present invention can reliably convey one side of the transfer material without mechanically touching it, thereby eliminating image disturbance caused by contact with the unfixed surface. It has the following effects.

[Brief explanation of drawings]

FIG. 1 is a configuration diagram showing one embodiment of the present invention, FIG. 2 is a side view showing an example of the structure of the electrostatic adsorption conveyance belt, and FIG.
The figure is a sectional view of the main part, Figure 4 is an electrode arrangement diagram showing the arrangement of comb-shaped electrodes, Figure 5 is a schematic diagram showing another embodiment, and Figure 6 is a schematic diagram showing another embodiment.
The figure is a schematic diagram of still another embodiment showing an application example. [Explanation of symbols] (3)・・・・・・Paper +? ), <7a)~(
7c)...Transfer means f81 (8a) to (8c
)... Paper conveyance device (9)... Electrostatic adsorption belt +121... Semi-conductive film (18a) (
18b) - Electrode

Claims (1)

[Claims] One or more devices, which are development image transfer devices in an electrophotographic apparatus, which apply a voltage to a group of parallel electrodes of a support conveyance member to electrostatically attract and convey a transfer material via a semiconductive film; A transfer device characterized by further comprising means for transferring a developed image.