JPH01263676A - Transfer device - Google Patents

Abstract

PURPOSE:To improve the efficiency of toner removal and to obtain a clean copy by providing a blade which contacts a transfer belt and a means which removes paper powder from the surface of the transfer belt positioned on the upstream side of an electrostatic charging means on the upstream side. CONSTITUTION:In the transfer device 131, the transfer belt 14 is moved as shown by an arrow (c) by a roller 17 in synchronism with the rotation of a photosensitive drum 3 and a sheet to which a toner image is transferred is separated from the belt 14 in a separation area Y where the sheet changes its direction suddenly at the position of the roller 15 and sent to a paper discharge part through a fixing device. A paper removing roller 25 removes paper powder from the belt 14 having passed through the area Y. The paper powder which is collected by the roller 25 is scraped by a blade 27 and removed to clean the roller 25. The particle size of toner is smaller than the paper powder and large-diameter paper powder is removed principally by the roller 25. The belt 14 from which the paper powder is removed has toner removed by a blade 24.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a transfer device that uses an endless transfer belt to transfer toner held on the surface of an electrostatic latent image carrier onto a sheet.

(Prior Art) Conventionally, the transfer device includes: (i) an endless transfer belt that is wound around a plurality of rollers and rotates and moves while contacting an electrostatic latent image carrier based on the rotation of the rollers; 1. a charging device such as a charger that applies an electric charge to the surface of the transfer belt; and (iii) a charging device located upstream of the charging device with respect to the rotational direction of the transfer belt to remove impurities such as toner attached to the transfer belt. a blade-type cleaning device, wherein the transfer belt charged by the charging means and the electrostatic latent image carrier carrying the toner image are sandwiched and transported for sorting, and at that time, the toner image is electrostatically charged. A method that transfers images onto sheets has been proposed.

(Problems to be Solved by the Invention) However, in the transfer device, the sheet is held in close contact with the sheet by the electrostatic force caused by the charge applied to the transfer belt, so that a considerable amount of paper powder adheres to the transfer belt.

Therefore, the blade-type cleaning device has a problem in that paper dust accumulates on the tip of the blade, reducing the toner removal efficiency of the blade and staining the sheet.

(Means for Solving the Problems) The present invention has been made to solve the above problems, and will be described with reference to FIG. 1.2 showing one embodiment. (19), an endless transfer belt (+4) wound around the transfer belt (19), and a charging means (charger) (21) for applying an electric charge to the transfer belt (14). Charged transfer belt (14)
In a transfer device (13), a transfer belt conveys the sheet while holding it, and transfers the toner held on the surface of the electrostatic latent image carrier (photoreceptor drum) (36) to the sheet. (14) In the direction of rotation [direction of arrow (c)], the sheet to which the toner has been transferred is rotated by the transfer bell) (
A blade (23) in contact with the transfer belt (14) and a blade (23) in contact with the transfer belt (14) on the downstream side of the area separated from the transfer belt (14) [separation area] (Y) and on the upstream side of the charging means (2I). ) is located upstream of the transfer belt (14) and removes paper dust from the surface of the transfer belt (14).
(24) and .

(Function) In the transfer device (13) having the above configuration, the transfer belt (14) is given a predetermined electric charge based on the discharge of the transfer charger (20) while rotating in the direction of the arrow (C).

The toner image formed on the surface of the electrostatic latent image carrier (3) is conveyed in the direction of arrow (a), and is transferred to a transfer area (where the electrostatic latent image carrier (3) and the transfer belt (14) face each other). The image is transferred to the sheet conveyed to X).

The sheet is held based on the electrostatic attraction force acting between the sheet and the transfer belt (14), and is conveyed in the direction of arrow (C) in close contact with the sheet.

Then, paper dust is removed from the surface of the transfer belt (14) from which the sheets have been separated in the separation area (Y) by a paper dust removing means (24), and residual toner is removed by a subsequent blade (23).

(Example) Hereinafter, the present invention will be described with reference to the accompanying drawings showing one example.

FIG. 1 is a schematic sectional view of a copying machine, and FIG. 2 is a sectional view of a transfer device according to the present invention. A plurality of rollers (15), ~, (16)
is wrapped around. Further, the roller (16) is arranged to face the photoreceptor drum (3), and is pressed against the outer circumference of the photoreceptor drum (3) with the belt (14) sandwiched between the rollers (20). Further, a charger (21) and a cleaning device (22) are arranged outside the transfer belt (I4) located between the rollers (17) to (19).

The cleaning device (22) includes a collection box (23).
), a blade (24) located in the collection box (23) and in pressure contact with the roller (18) via the transfer belt (14), and a roller (19) sandwiching the transfer belt (14).
) and is pressed against the roller (19) via the transfer belt (14) by a spring (26); It consists of a blade (27) made of maltplane that presses against the outer circumference of the powder removal roller (25).

The surface of the paper dust removal roller (25) is coated with a highly insulating material such as polytetrafluoroethylene, vinyl chloride, polyester, etc., and the transfer belt (14) is charged by friction due to contact with the blade (27). The paper dust on top is absorbed.

In a copying machine equipped with the transfer device (13) having the above configuration, when a copy start signal is input, the photosensitive drum (3)
While rotating, its surface is charged to a predetermined voltage by discharge from the charger (4).

In addition, in the optical system (5), the exposure lamp (6) is
) direction and is covered by an opening/closing cover (2) provided on the top of the copying machine body (1) (not shown).
The upper original is irradiated with light, and the reflected light is exposed to the charged surface of the photosensitive drum (3) along the dashed-dotted line, forming an electrostatic latent image corresponding to the original image.

This electrostatic latent image is visualized as a toner image by supplying toner from the developing device (7), and the toner image and the photoreceptor drum (3) are irradiated with light by the pre-transfer eraser (8). Electrostatic force is reduced.

On the other hand, in the transfer device (13), the roller (I7) is driven by a driving means (not shown) in synchronization with the rotation of the photoreceptor drum (3).
rotates, and the transfer belt (14) follows the arrow (C).
) direction, other rollers follow and rotate, and the surface of the transfer belt (14) is uniformly charged to a predetermined potential by the charger (21).

Further, the sheet fed from the paper feed cassette (11) or (12) is brought into contact with the photosensitive drum (3) and the transfer belt (14) in time with the toner image by a timing roller (12). It is transported to the transfer area (X).

Here, the charged toner on the photoreceptor drum (3) is electrostatically transferred to the sheet conveyed between the transfer belt (14) and the photoreceptor drum (3) and the roller (16) and the photoreceptor drum (3). 3
) is transferred by pressure.

This and the transfer belt (1
4) The arrow (
Separation area (Y) where the sheet is conveyed in the direction C) and changes direction abruptly at the roller (15) due to the stiffness of the sheet itself.
The toner images are separated from the surface of the transfer belt (+4) by the fixing device (29), sorted and fixed, and then discharged to the paper discharge section (30).

The transfer belt (+4) that has passed through the separation area (Y) is in contact with the paper dust removal roller (25),
Paper dust is removed in step 5).

The paper dust collected by the paper dust removal roller (25) is
The paper dust is removed by scraping with a blade (27), and the paper dust removal roller (25) is cleaned. Therefore, the paper dust removal roller (
25) The paper dust removal performance is regenerated and maintained.

Note that the particle size of toner is smaller than paper dust, and the paper dust removal roller (25) mainly uses large-diameter paper dust.

removed.

The transfer belt (14) from which paper dust has been removed is moved by the blade (2
4) The toner is removed at the tip in preparation for the next transfer.

Here, since paper dust has already been removed from the surface of the transfer belt (14), the performance of the blade (24) will not deteriorate due to paper dust accumulating on the tip of the blade (24).

The paper dust and toner scraped off by the blades (27) and (24) fall into a collection box (23) and are collected, and the collection box (23) is appropriately taken out and disposed of.

A mylar sheet (28) is attached around the upper opening of the collection box (23) to prevent toner from scattering.

In the above embodiment, a paper dust removing roller (25) was provided as a paper dust removing means, and this was brought into contact with the transfer belt (1, 1), but a roller having a radial brush was rotationally driven. , the toner may be removed using the brush.

(Effects of the Invention) As is clear from the above description, in the transfer device according to the present invention, paper dust on the transfer belt is removed by the paper dust removal means, and the toner removal ability of the toner removal blade provided on the downstream side is improved. Can be maintained properly.

Therefore, toner does not adhere to the sheet from the transfer belt, and clean copies can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing a schematic configuration of a copying machine, and FIG. 2 is a schematic sectional view of a transfer device. ■... Main body, 2... Opening/closing cover, 3... Photosensitive drum, 13... Transfer device, 14...
Transfer belt, 15. ~． I9...roller, 2I...
Charging chart, 22...Cleaning device, 23.
...Collection box, 2.1...Blade, 25...Paper dust removal roller, 27...Blade. Patent applicant Minolta Camera Co., Ltd.

Claims (1)

[Claims] (1) comprising an endless transfer belt wound around a plurality of rollers and a charging means for applying an electric charge to the transfer belt, and conveying the sheet while holding it with the transfer belt charged by the charging means; In a transfer device that transfers the toner held on the surface of the electrostatic latent image carrier at a portion facing the electrostatic latent image carrier onto the sheet, the sheet to which the toner has been transferred is separated from the transfer belt with respect to the rotational direction of the transfer belt. a blade that contacts the transfer belt downstream of the area where the charging means is located and upstream of the charging means; and a paper dust removal means that is located upstream of the blade and removes paper dust from the surface of the transfer belt. A transfer device characterized by being provided with.