JPS58105270A - Electrophotographic device - Google Patents

Abstract

PURPOSE:To cause no transfer shift in the end part even in case of a single slip, by providing a sheet guide so that its width protrudes from both ends of a transfer charger, and also holding both lug parts of a sheet by a follower roll. CONSTITUTION:One end of a sheet guide 14 is supported by a shaft 15 so as to be freely turnable, is energized clockwise by a spring 16, both edge parts of the other end are made wider than width of a transfer charger 8, and a follower roll 17 is provided so as to peep out of the upper face. When a printing paper 6 is fed, an electromagnet 19 is energized and the guide 14 is turned counterclockwise so that the paper 6 is inserted easily. When the paper 6 has reached the charger 8, the electromagnet 19 is de-energized, and the guide 14 is reset. In case when the end part of the paper 6 has come to the transfer position, both lug parts are pinched by the guide 14 and are held by the roll 17, therefore, tightly adhere to a drum 1 and pass through. Therefore, the paper tightly adheres to the drum 1, and no printing blur is generated even in the end part.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is an electrophotographic method in which a desired print is obtained by forming an electrostatic latent image on a photoreceptor, then forming a toner image, transferring it to a cut sheet, and fixing it. Regarding equipment.

This will be explained below with reference to the drawings.

FIG. 1 is a side view showing a conventional electrophotographic apparatus. In the figure, reference numeral 1 denotes a photoreceptor for forming an electrostatic latent image, and generally a drum is used.

2 is a primary charger for charging the photosensitive drum 1;
3 is by irradiating the charged photosensitive drum 1 with light,
4 is a light source for forming an electrostatic latent image (destroying or leaving the charge on parts other than the shape of desired characters, images, etc.); 4 is a light source for forming an electrostatic latent image; 5 is a sheet guide that guides the printing paper 6 so that it comes into close contact with the photosensitive drum 1; 7 is a feed roller; 8 is a developer that forms the characters, images, etc. formed on the photosensitive drum 1; A transfer charger having a wire electrode 8a for transferring 1 to the printing paper 6; 9 an eraser for erasing an afterimage on the photosensitive drum that is no longer needed after transferring to the printing paper 6 by irradiating light or the like; 10
is a cleaning device that removes toner adhering to the photosensitive drum, and may be a device using a magnetic brush, or may be a device that scrapes off toner with a brush or a blade.

No. 1 is a conveyor belt that conveys the printing paper after transfer, and No. 12 is a fixing device, whether it is due to compression or heat fixing.
, and it is common to use both of the above. 13 is plywood.

When printing on a single sheet using such an electrophotographic apparatus, as shown in detail in FIG. is separated from the transfer drum due to the stiffness of the printing paper 6 itself. For this reason, there is a drawback that transfer misalignment occurs near the trailing edge of the printing paper 6.

Therefore, in the present invention, the width of the sheet guide is set so as to protrude from both ends of the transfer charger, and at the position corresponding to the transfer charger when viewed from the feeding direction, the printing paper is held on both sides of the transfer charger. 2. In order to guide the photosensitive drum so that it can come into close contact with the photosensitive drum. Moreover, it is an object of the present invention to provide an electrophotographic apparatus that does not cause transfer misalignment or the like near the end of printing paper even when printing a single sheet.

FIG. 3 is a side view showing one embodiment of the present invention, in which the same parts are given the same numbers.

In FIG. 3, reference numeral 14 denotes a sheet guide that guides the fed printing paper 6 to the transfer charger 8, and is rotatably supported around a shaft 15, with one end 14g extending in a concentric circle with the shaft 15. It is constructed in the shape of an eggplant.

Reference numeral 16 indicates a spring by which this seat urges the id 14 clockwise, and reference numeral 17 indicates a seat guide 1 as shown in FIG.
A follower roller 18 is rotatably provided in both ends near the other end of the ID 14 so that the sheet slightly peeks over the top surface of the ID 14. A sensor 19 that emits an output is excited by the output signal of the sensor 18, and attracts the sheet guide 14 in a counterclockwise direction to widen the gap between the sheet guide 14 and the photosensitive drum 1, making it easier to insert the printing paper 6. It is an electromagnet. ,.

Next, the operation of the present invention configured as described above will be explained.

First, after the photosensitive drum 1 is uniformly charged with the -order charger 2, it is irradiated with light from the light source 3 to break down the electrostatic charge, leaving only characters or images on the drum, or conversely, leaving only letters or images on the drum. An electrostatic latent image is formed leaving only a portion of the image. Next, toner is supplied by the developing device 4, and the toner is applied only to the above-mentioned character or image portion formed on the photosensitive drum, or vice versa.

In this state, the printing paper 6 is fed in synchronization with the rotation of the photosensitive drum 1, and the arrival of the printing paper 6 is detected by the sensor 1.
8, and based on this detection signal, the electromagnet 19 is excited and the sheet guide 14 is rotated counterclockwise to facilitate insertion of the printing paper. The leading edge of the printing paper is the transfer charger 8
When reaching the vicinity of , the electromagnet 19 is de-energized and the sheet guide 14 is returned clockwise by the spring 16.

Therefore, the print paper 6 is pressed by the follower roller 17 and comes into close contact with the photosensitive drum 1.

When the photosensitive drum passes through the transfer charger 8 in this closely contacted state, for example, if a negative voltage is applied to the wire electrode 8a, the characters or images on the photosensitive drum are transferred to the printing paper.

Subsequently, the image is fixed by the fixing device 12, allowing complete printing.

Eventually, the vicinity of the end of the printing paper 6 comes to the transfer position, but since both edges of the printing paper 6 are held down by the follower rollers 17, the end of the printing paper 6 remains in close contact with the photosensitive drum 1 until the transfer position is reached. pass.

Therefore, according to the present invention, printing does not occur even near the trailing edge 11 of the printing paper 6.

As described above in detail, according to the present invention, since the sheet guide 14 is made rotatable about the shaft 15, it is easy to insert the printing paper.

In addition, since the sheet is provided with follower rollers that press both ears of one printing paper 6 at both ends near the tip of the ID 14, the printing paper can be brought into close contact with the photosensitive drum 1 even near the end of the printing paper. Is it printed near the end of the file? Printing is possible without causing scratches.

Furthermore, in the present invention, since one end of the seat guide 14 is formed concentrically with the two rotation shafts 15, when the seat guide 14 is rotated counterclockwise, the one end becomes larger than the plate surface before rotation. There is less protrusion, and fed printing paper does not get stuck.

[Brief explanation of drawings]

FIG. 1 is a side view showing a conventional electrophotographic apparatus, FIG. 2 is a partially detailed view of FIG. 1, FIG. 3 is a side view showing an embodiment of the present invention, and FIG. 4 is a side view of FIG. It is a bottom view. DESCRIPTION OF SYMBOLS 1... Photosensitive drum, 2... -order charger, 3... Light source, 4... Developing device, 5... Sheet guide, 6...
Printing paper, 2...Feed row 2.8...Transfer charger, 9...Eraser, 10...Cleaning device,
11... Conveyance belt, 12... Fixing device, 13...
・Base plate, 14... Seat guide, 15... Rotation shaft,
16...Spring, No...Follow roller, 1
8...Sensor, 19...Electromagnet. ;1 Patent applicant Oki Electric Industry Co., Ltd.

Claims (1)

[Claims] By irradiating a uniformly charged photoreceptor with light, a desired electrostatic latent image is formed on the photoreceptor, toner is attached to this electrostatic latent image, and then transferred to printing paper, In an electrophotographic apparatus that performs desired printing by fixing, a sheet guide that rotates around one end to widen or narrow the gap between the sheet guide and the photoreceptor, and a sheet guide provided at both ends near the tip of the sheet guide. 2. An electrophotographic apparatus comprising: a follower roller that slightly peeks over the upper surface of the sheet guide and brings both edges of the printing paper into close contact with the photoreceptor.