JPS5850347B2 - Dirt prevention device for electrophotographic optical system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a stain prevention device for an optical system for electrophotography.

Compared to lens-based optical systems, electrophotographic optical systems have the advantage of being lower in cost, allowing the equipment to be more compact, and eliminating the need for mirrors, as well as eliminating the difference in illuminance between the center and the periphery. Focusing light transmitters have recently begun to be used.

However, the focusing light transmitter is 0.771L771~1.07
It is an array of optical elements such as glass fibers with a diameter of 717H, and each optical element operates individually, so if toner or dust adheres to the light entrance or light exit of the optical element, the image will not be formed in that area and the image will not be formed. Unnecessary background smudges may occur, resulting in poor image quality.

When creating an image using the entire surface of the lens or mirror, as in the case of a lens system, a small amount of toner or dust attached will not have a great effect on the image, but with a convergent light transmitter, the part to which toner or dust has adhered will The effect is significant in that the optical path is completely cut off, and preventing contamination of the convergent optical transmitter is a major issue.

The present invention aims to provide means for solving the above problems.

The details of the present invention will be explained with reference to the drawings with reference to embodiments.

In FIG. 1, light from a light source 1 such as a halogen lamp is reflected by an original 3 on a contact glass 2, and an image is formed on a photoreceptor drum 5 by a focusing light transmitting member 4, such as SELFOC (trade name).

A diaphragm 6 is provided between the focusing light transmitter 4 and the photosensitive drum 5.

As shown in FIG. 2 or 3, the convergent light transmitter 4 is provided with electrodes 7 on the side surfaces or end surfaces of the input port 4a and the output port 4b, and each electrode is connected to a high-voltage power source 9.

An electric field 10 is formed between the electrodes 7 that are arranged opposite to each other near the entrance 4a and near the exit 4b, and each electric field surrounds the opening end of the optical element 8 on the entrance side and the exit side of the focusing light transmitter 4. It is formed like this.

With this structure, even if floating objects such as toner or dust come near the optical system, that is, the focusing optical transmitter 4, they will be removed along the electric field (
It does not move toward the electrode of either 1) or (c) and cross the electric field to penetrate into the focusing light transmitter.

In other words, it is possible to eliminate toner and dust from adhering to the optical elements of the convergent light transmission body.

In most cases, toner, dust, etc. that adversely affect the focusing light transmitter are scattered from the surface of the photoreceptor.

Therefore, by shielding the space between the photoreceptor drum 5 and the convergent light transmitter 4, it is possible to almost avoid toner and dust from adhering to the convergent light transmitter.

However, since the light from the convergent light transmitter 4 must be projected onto the photoreceptor drum 5, the space between the convergent light transmitter 4 and the photoreceptor drum 5 cannot be completely shielded.

In order to solve this problem, as shown in FIG. 4, the diaphragm 6 provided between the convergent light transmitter 4 and the photosensitive drum 5 is formed as an diaphragm lever 6' pivotably mounted on the partition plate 11 and capable of tilting up and down. However, except for the aperture lever 6', the focusing light transmitting body 4 is shielded from the photosensitive drum 5 by a partition plate 11.

The aperture lever 6' is tilted up and down depending on the luminous flux, and the aperture lever 61 is connected to the high-voltage power source 9 and formed as two electrodes facing each other.

An electric field is formed between the opposing aperture levers 6' by applying a high voltage, and toner and dust scattered from the photosensitive drum 5 are blocked by the electric field and cannot enter the optical system.

Therefore, it was possible to prevent the optical system from being contaminated and adversely affecting the image.

If the example of FIG. 2 or 3 is used in conjunction with the example of FIG. 4, the effect of preventing contamination of the optical system will be nearly perfect.

Note that by making each electrode removable, it is also possible to clean toner, dust, etc. attached thereto.

[Brief explanation of the drawing]

FIG. 1 is a partial explanatory diagram of an electrophotographic apparatus using a focusing light transmission body, FIGS. 2 and 3 are explanatory diagrams of different embodiments of the apparatus according to the present invention, and FIG. FIG. 7 is an explanatory diagram of yet another embodiment of such a device. 4... Focusing light transmission body, 5... Photosensitive drum, 6... Aperture, 6'... Aperture lever 7... Electrode, 9... High voltage power supply,
10... Electric field, 11... Partition plate.

Claims (1)

[Claims] 1. In an electrophotographic device that uses a focusing light transmitter as an optical system, two opposing electrodes are provided near the optical system, and a high-voltage power source is connected to the electrodes, so that the electric field formed between the electrodes is connected to the optical system. A contamination prevention device for an optical system for electrophotography, characterized in that the electrode is arranged so as to block the intrusion of toner particles and the like.