JPS59184377A - Electrophotographic device - Google Patents

Abstract

PURPOSE:To execute easily carrying of a transfer material, a transfer of a toner image, and also separation of an electrostatic latent image holding member and the transfer, by charging electrostatically an insulating layer of an endless electrostatically charged belt which has formed an insulating layer on the upper face of a conductive layer, and using an adsorbing force caused by its electrostatic force. CONSTITUTION:An electrostatically charged belt 18 has a conductive layer 18a, and an insulating layer 18b formed on its upper face. When paper 5 is supplied between resist rollers 9a, 9b by a rotation of a semicircular roller 8, the electrostatically charged belt 18 carries the paper 5 toward a photosensitive drum 1 in a state that it is adsorbed to the surface of the insulating layer 18b. As a result, when the paper occupies a position just below the photosensitive drum 1, a toner image formed on a photosensitive surface 1a is attracted and transferred on the surface of the paper 5 by an attracting force of an electrostatically charged charge of the insulating layer 18b operated through the paper. Thereafter, the paper 5 is carried toward a fixing part 6 in a state that it remains adsorbed to the electrostatically charged belt 18 without being adsorbed by the photosensitive drum 1.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electrophotographic apparatus, and more particularly, to an electrophotographic apparatus in which a toner image obtained by developing a transfer material is transferred by electrostatic adsorption force of charges charged on a charging belt.

FIG. 1 is an explanatory diagram conceptually showing an electrophotographic apparatus, a device called patented xerography.

As shown in the figure, in this electrophotographic apparatus, the surface of a photosensitive drum 1 is a photosensitive surface 1a coated with a photoconductive and insulating material such as selenium. A predetermined electrostatic latent image is formed by being charged with electricity in the exposure section 3, and then a predetermined electrostatic latent image is formed in the developing section 4, and a toner image is obtained by developing the electrostatic latent image in the developing section 4. This toner image is applied to the surface of the sea bream 5. After being transferred, the image is fixed in a fixing section 6. On the other hand, paper 5
is stored in the cassette 7, and the half-moon row 28 rotates to open the registration row 29a.

It is designed to be inserted into 9b. At this point, the registration rollers 29a and 9b are stopped, so the leading edge of the paper 5 comes into contact with the registration rollers 9a and 9b and sag, thereby aligning the leading edge of the paper 5 with the photosensitive drum. 1. Paper 5 is photosensitive drum 1
When the corona charger 1o is positioned downward, the back surface of the corona charger 1o is charged, and the photosensitive surface 1 is charged by the electrostatic force of the charge at this time.
The toner image formed on a is attracted and transferred.

In such an electrophotographic apparatus, it is necessary to peel off the paper 5 from the photosensitive drum 1 after transferring the toner image. This is because the zero paper 5 is attracted to the photosensitive drum 1 due to the electrostatic force of the charges on the photosensitive surface 1a. For this reason, various paper separation methods have been proposed as described below.

1) Buffer method In this method, a buffer device 11 as shown in FIG. 1 is provided, and this buffer device 11 blows compressed air onto the boundary line between the photosensitive drum 1 and the paper 5 to separate the two. It is. Although this method can separate the paper 5 most reliably, it is particularly bulky and is therefore particularly applicable to large-sized devices.

11) Separation belt method This method is shown in Figures 2 to 4 (a), (b),
(c) As shown in K, separation belts 12, 13, and 14 are provided, and external force is applied to one of the ends of the paper 5 in the conveying direction to separate the photosensitive drum 1 and the paper 5. . To further comment, the separation belt system shown in FIG. 2 has pins 15a on both the left and right sides of the photosensitive drum 1.

15b, and a separation belt 12 is fixedly stretched between the pins 15a and 15b. As a result, the center portion of the separation belt 12 is in contact with one end portion of the photosensitive drum 1 in the axial direction, and this portion is interposed between one end portion of the transported paper 5, thereby separating the paper 5. In the separation belt system shown in FIG.
It is a structure that has been strung up. Therefore, the separation belt 13 is an endless belt that moves at the same speed as the photosensitive drum 1, and like the separation belt 12, the separation belt 13 separates the paper 5 by being interposed at one end of the transported paper 5. be done.

The separation belt system shown in FIGS. 4(a), 4(b), and 4(c) consists of white rollers 17a and 17b arranged at the same positions as the pins 15a and 15b, and a photosensitive drum below these. A separation belt 14 is twisted and stretched around rollers 17c and 17d arranged between rollers 17a and 17b on the outer side of the roller 1 in the axial direction. As a result, the separation belt 14 becomes an endless belt that contacts one end of the photosensitive drum 1 in the axial direction between the rollers 17a and 17b, and when the paper 5 is conveyed, it contacts the one end of the photosensitive drum 1 and separates the photosensitive drum. 1
It is designed to separate by pulling outward in the axial direction.

All of these devices require small bulk and can separate the paper 5 relatively reliably, so they are mainly applied to small devices.

111) Separate charger method This method uses AC corona generated by a separate charger to eliminate the charge on at least one of the photosensitive surface 1a or the paper 5 after the toner image is transferred, thereby preventing the paper 5 from being attracted to the photosensitive drum IK. However, because it is difficult to completely remove static electricity, separation often fails.

Although the various paper separation methods according to the prior art have been outlined above, each method has its advantages and disadvantages.

In view of the above-mentioned prior art, the present invention provides a method for supplying a transfer material, which enables reliable separation of a transfer material with a small bulk, and facilitates reversal of the transfer direction of the transfer material after transferring a toner image onto the transfer material. An object of the present invention is to provide an electrophotographic apparatus having an image transfer and transfer material separation mechanism. The present invention achieves this object by charging the insulating layer of a charging belt, which is an endless belt in which an insulating layer is formed on the upper surface of a conductive layer, and adsorbing a transfer material by the adsorbing force caused by the electrostatic force of the charging belt. The technical idea is based on the fact that the electrostatic latent image holding member is transported to the electrostatic latent image holding member, the toner image is transferred, and the electrostatic latent image holding member and the transfer material can be easily separated. .

Embodiments of the present invention will be described in detail below based on the drawings. Note that parts that are the same as those in the prior art are given the same numbers and redundant explanations will be omitted. As shown in FIG. 5, the charging belt 18 is an endless belt stretched between a registration roller 9b and a roller 19 disposed on the opposite side with respect to the vertical center line of the photosensitive drum 1. As shown in FIG. 6, it has a conductive layer 18a and an insulating layer 18b formed on the upper surface thereof. Thus, in the charging belt 18, the insulating layer 18b is charged by the corona charger 10, which is a charging means, using the conductive layer 18a, which is at ground potential, as a counter electrode. As a result, the charging belt 18 can attract the paper 5 by the electrostatic force of the charged charges, and can also attract and transfer the toner image via the paper 5.

In this embodiment, when the paper 5 is supplied between the registration rollers 9a and 9b by the rotation of the half-moon roller 8, the charging belt 18 is transferred to the corona charger 10 and the insulating layer 18b is
Since the paper 5 is charged, the paper 5 is conveyed toward the photosensitive drum 1 while adsorbed to the surface of the insulating layer 18b. Thus, when the paper 5 is located directly below the photosensitive drum 1, the toner image formed on the photosensitive surface 1a is attracted to the surface of the paper 5 due to the attraction force of the electrical charge of the insulating layer 18b acting through the paper 5.・Transferred. Thereafter, the paper 5 is conveyed toward the fixing section 6 as shown by an arrow in the figure while being attracted to the charging belt 18 without being attracted to the photosensitive drum 1.

FIGS. 7(a) and 7(b) each show an embodiment in which the conveyance direction is reversed after transfer. In the embodiment shown in FIG. 7(,), a charging belt 20 having the same structure as the charging belt 18 is an endless belt stretched between a registration roller 9a and rollers 21a and 21b.

At this time, the row 221a is disposed directly below the photosensitive drum 1, and the roller 21b is disposed on the same side as the registration roller 9a (left side in the figure) with respect to the vertical center line of the photosensitive drum 1. However, in the embodiment shown in FIG. 7(b), the charging belt 22 having the same structure as the charging belt 18 is connected to the registration roller 9.
It is an endless belt stretched between a and rollers 23.

On both actual flow sides, the charging belts 20 and 22 are charged with their conductive layers 2. The insulating layer 2 with Oa and 22a as the counter electrode
Since 0b and 22b are charged, the paper 5 is removed from the cassette 7.
・At this time, the paper 5 is lower than the charging belt 20.22, that is, its surface is facing downward, but it is attracted by the electrostatic force of the insulating layers 20b and 22b without falling and is exposed to light. It is conveyed toward the drum 1. Then, when the toner image is positioned directly below the photosensitive drum 1, the toner image is transferred in the same manner as in the above embodiment, and thereafter the charging bell) 20.2
As the moving direction of the paper 5 is reversed, the conveyance direction of the paper 5 is also reversed and the paper 5 heads toward the fixing section 6. Figures 7(a) and (b) show paper 5.
The direction of transport is indicated by an arrow. In order to improve such reversal, the embodiment shown in FIG. b)
In the embodiment shown in K, a guide plate 26 guides the paper 5 toward the roller 23 by a curved portion that follows the curvature of the row 223.
has.

In each of the above embodiments, the paper 5 is a charging belt 18.20
．． Conveyance to the photosensitive drum 1, transfer, and separation are performed by the electrostatic force 22. In particular, in order for the transfer and separation to be performed well, the electrostatic force must be greater than the electrostatic force on the photosensitive surface 1a. . Further, although the electrostatic latent image holding member has been described as a drum-shaped photoreceptor, it goes without saying that the present invention is not limited to this example and that a belt-shaped photoreceptor may be used.

As specifically explained above in conjunction with the embodiments, according to the present invention, the insulating layer of the charging belt can be charged, so that paper can be attracted and conveyed. , transfer and separation can be performed well, and the conveyance direction can be easily reversed.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram conceptually showing a conventional electrophotographic apparatus having a buffer device as a paper separation method, and FIGS. 2 and 3 show a first separation belt method as a paper separation method according to the prior art. FIG. 4(a) is an explanatory diagram conceptually showing the third example of the separation belt system as seen from the front, and FIG. 4(b) is an explanatory diagram conceptually showing the third example of the separation belt system. 4(c) is a perspective view thereof, FIG. 5 is an explanatory diagram conceptually showing the first embodiment of the present invention, and FIG. 6 is a cross-sectional view of the charged belt. 7(a) is an explanatory diagram conceptually showing a second embodiment of the present invention, and FIG. 7(b) is an explanatory diagram conceptually showing a third embodiment of the present invention.゛) In the drawing, 1 is a photosensitive drum, 1a is a photosensitive surface, 5 is paper, 9a, 9b are registration rollers, 10 is a roller, a charger, 18, 20, 22 is a charging belt, 18a, 20a, 22a are conductive Layers 18b, 20b, 22b are insulating layers. Patent Applicant Fuji Photo Film Co., Ltd. Representative Patent Attorney Shibu Mitsuishi (and 1 other person) Procedural Amendment June 7, 1982 To the Commissioner of the Japan Patent Office 1, Indication of Case 1982 Patent Wish No. 58759 Showa era
Case No. 2, Name of the invention Electrophotographic device 3, Relationship with the idea of doing hli + IE Patent application 210 Nakanuma, Minamiashigara City, Kanayo Prefecture (520) Fuji Photo Film Co., Ltd. 4 Agent postal code 107 6, Amendments will be made to drawings to be amended, drawings 7, contents of amendments, and notices that are not included in the attached drawings, including Figs. 1 and 5. 8. List of attached documents

Claims (1)

[Claims] A toner image obtained by developing one electrostatic latent image formed on the electrostatic latent image holding member is transferred to a separately supplied transfer material as this transfer material moves and the electrostatic latent image holding member moves. In an electrophotographic apparatus having a transfer step, the electrophotographic apparatus includes a conductive layer and an insulating layer formed on the upper surface of the conductive layer, and the insulating layer is charged by a charging means, and the electrophotographic apparatus is charged with a conductive layer supplied from a transfer material storage section such as a cassette. An electrophotographic apparatus comprising an endless charging belt that attracts and conveys a transfer material by the electrostatic force of the insulating layer and separates the toner image from the electrostatic latent image holding member after transferring the toner image onto the transfer material.