JPS6352172A - Electrophotographic printer - Google Patents

Abstract

PURPOSE:To transfer a visualized image to printing paper by means of a transferring means after stopping a photosensitive belt so as to simplify the constitution of a printer, by providing the endless photosensitive belt which can be run in a direction orthogonal to the printing paper feeding direction and visualizing a latent image formed against the belt. CONSTITUTION:Printing paper 11 is closely faced to the endless photosensitive belt of this printer and at this position the paper 11 is fed and wound around pulleys 12 and 13 so that the paper can be run in a vertical direction. A driving motor 15 is coupled with the driving side pulley 12 by means of a clutch 14. A belt driving means 16 is constituted of these mechanisms and controlled by a belt start/stop control circuit. Moreover, printing information is recorded on the belt 10 as latent images by electrifying one surface of the belt with negative charges by means of a corona discharger 19 provided along the belt 10 and radiating the belt 10 with rays of light of the printing information by means of an LED array 20. The recorded latent images are transferred to the printing paper 11 by means of a transferring means 23 after the latent image is developed and visualized by a developing device 21.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an electrophotographic printer that performs printing using an electrophotographic method.

[Prior Art] In the electrophotographic recording method, recorded information is recorded on a photoreceptor as an electrostatic latent image, and toner (developer) is attached to this latent image to make it visible. This is a method of transferring images onto paper, and is used in copying machines and the like, but in recent years, this electrophotographic method has also been adopted in printers.

As shown in FIG. 2, a conventional electrophotographic printer has a structure using a photosensitive drum 1 formed by coating a photoconductive material 1b on the surface of a conductive cylindrical substrate 1a.

During printing, the photosensitive drum 1 is rotated, the surface of the photosensitive drum 1 is negatively charged by the charger 2, and then, for example, an exposure means such as an LED array 3 is irradiated with light according to the print information. A latent image is formed on the surface of the photosensitive drum 1 by causing the charged portion to lose its charge, and then positively charged toner is attached to the surface of the photosensitive drum 1 by the developing device 4 to develop the latent image. and then the transfer device 5
The toner image is electrostatically transferred to the paper 6 by the image forming apparatus 6, and then fixed by the fixing device 7. 8 is a static elimination lamp, and 9 is a cleaner.

The electrophotographic printer described above has various excellent features, such as the following. First, compared to impact dot printers, it is easier to increase the density of the dots that make up characters, and high print quality can be obtained.Second, it is possible to print at a speed that is, for example, five times faster than impact dot printers. M3 can be printed on plain paper, so the running cost is low. PLS4 is a non-impact method, so it has low noise, and has excellent environmental friendliness, which is a strong requirement in office automation.Fifth, it can be printed in color. It is easy, etc.

Problems to be Solved by the Invention] However, the above-mentioned conventional electrophotographic printer using a photosensitive drum has the following deficiencies.

First, the equipment is expensive. In particular, when a laser beam method is adopted as an exposure means that irradiates light onto a charged photosensitive drum to form a latent image, it is necessary to control the laser beam with high precision, but the laser optical system and FI structure for this purpose are required. It is complicated and the exposure means is expensive. Furthermore, even if a 7-ray LED (light-emitting diode) system is adopted as the exposure means, in the conventional system, the 7-ray LED has the same width as the paper, and the number of recording dots, for example 1000, can be recorded within that width.
Since it constitutes a large number of LEDs, such as 2,000 LEDs, it is expensive, and the price of the photosensitive drum is also high.

Second, the device becomes larger. Since the photosensitive drum occupies a large space, it is difficult to miniaturize it.

Further, regarding the exposure means, in the laser beam method, the laser optical system and the Wi-ring structure occupy a large space, and even in the LED 7-ray method, the LED array has the width of the paper, so it is large in size.

The rjS3 requires periodic replacement of many parts, such as the photosensitive drum 1 and the developing device 4, which have short maintenance cycles.

Therefore, maintenance costs are high.

As mentioned above, electrophotographic printers have excellent features, and at the same time, they require miniaturization and
There were many obstacles to lower prices.

The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide an electrophotographic printer that can be easily reduced in size, price, and maintenance costs.

Means for Solving Problem E] In order to solve the above problems, the present invention provides a photosensitive belt formed by coating a photoconductive material on the surface of an endless belt base made of metal or conductive plastic; A belt driving means for driving the photosensitive belt close to the paper in a direction perpendicular to the feeding direction of the paper; an exposing means for recording an electrical latent image; a developing means for making the latent image visible by depositing toner on the photosensitive belt on which the latent image is formed; The photosensitive belt must be stopped correctly so that the toner image can be printed correctly on the paper at the desired position.
Alternatively, the apparatus may be configured to include a belt start/stop control means for starting and a transfer means for transferring the toner image on the photosensitive belt stopped at a predetermined position onto a sheet of paper.

[Function] In the above configuration, the photosensitive belt runs in a direction perpendicular to the paper, and the exposure means irradiates light onto the running photosensitive belt to form an electrostatic latent image corresponding to print information. The latent image formed on the photosensitive belt is visualized by applying toner to it by a developing means.Then, the latent image is controlled by a belt start/stop control means, and the photosensitive belt is moved to a predetermined position relative to the paper. Stop at. At this point, the transfer means is activated, and the toner image on the photosensitive belt is transferred onto the paper.

[': Example Xa] FIG. 1 is a perspective view showing a main part of the internal structure of an electrophotographic printer according to an embodiment of the present invention. 10 is a photosensitive belt,
This photosensitive belt 10 is made of an endless belt base made of metal or conductive plastic and coated with a photoconductive material on the surface thereof. The photosensitive belt 10 is attached to the paper 11
The boo 912 on the driving side is wound around the pulleys 12 and 13 so as to be able to travel in the direction (arrow (b)) perpendicular to the feeding direction (arrow (a)) of the paper 11 at a position close to and opposite to the paper 11. It is connected to the drive motor 15 via.

The pulleys 12, 13, clutch 14, drive motor 15, etc. constitute belt drive means 16. This belt driving means 1
Although the details are omitted, 6 is controlled by a belt start/stop control circuit so that the toner image visualized on the photosensitive belt 10 can be correctly printed at a predetermined position on the paper 11, as will be described later. To correctly stop or start a photosensitive belt 10.

Facing the photosensitive belt 10, a static elimination lamp 17, a cleaner 18, a corona discharger 19, an LED array 20, and a developer 21 are arranged in order in the belt running direction.

The charge eliminating lamp 17 exposes the entire surface of the photosensitive belt 10 to remove all charges from the photosensitive belt 10.

The cleaner 18 is for mechanically removing residual toner on the photosensitive belt 10 from which electricity has been removed.

The corona discharger 19 is used to negatively weigh the photosensitive belt 10 over one side.

The LED array 20 irradiates the photosensitive belt 10 with light corresponding to the printed information and turns the irradiated part into a conductor.
The photoreceptor belt 10 is
This exposure means records printed information as a electrostatic latent image on the belt, and includes a plurality of LEDs arranged in a line in the width direction of the belt. The number of LEDs in this LED array 20 is
There are as many as are necessary in the vertical direction to print one line, and usually, for example, there may be no more than a few dozen.

The developing device 21 includes, for example, a magnet roll 21a in contact with the photosensitive belt 10, and uses a magnetic brush development method to deposit positively charged toner onto the photosensitive belt 10 on which a latent image is formed. Visualize the image.

In the embodiment, the corona discharger 19, the LED array 20, and the developer 21 are arranged on the side of the photosensitive belt 10 that approaches the paper 11, that is, in the vicinity of the driven pulley 13, and the static elimination lamp 17 and the cleaner 18 is photosensitive bell) 1
0, the side moving away from the paper 11, that is, the drive boot 9
It is located near 12.

A photosensitive belt guide 22 is provided inside a portion of the photosensitive belt 10 that faces the paper 11, and a transfer device 123 is provided opposite the photosensitive belt guide 22 side. This transfer device 23, which is a charger, is movable toward the photosensitive belt kite 22 as shown by the arrow (C), and while charging the paper 11, transfers the paper 11 to the photosensitive belt 10 using the photosensitive belt guide 22 as a support. The donor on the photosensitive belt 10 is electrostatically transferred to the photosensitive belt 11.

2=1 is a heat roller, which is a fixing device for heating the paper 11 and fixing the transferred toner image at a constant value of 'X1'.

This heat roller 24 also serves as a feed roller that feeds the paper by sandwiching the paper 11 between it and the bail roller 25, and is rotationally driven by a motor 26 via a belt 29 wound around pulleys 27 and 28. Ru.

The printing operation of the electrophotographic printer configured as above will be explained.

When one line of printing is completed, the photosensitive belt 10 is activated by the belt start/stop control circuit and runs in the direction of the arrow (b) to print one line of the dog. At this point, photosensitive belt 10
The upper photoconductive layer is turned into a conductor by the light from the static elimination lamp 17 and loses charge.

Therefore, the photosensitive belt 10 does not lose its ability to adsorb the toner remaining after the transfer of the previous row, and the remaining toner on the photosensitive belt 10 is easily removed by the subsequent cleaner 18.

The photosensitive bell) 10 that continues to run is a corona discharger 19
One side of the LED array is negatively charged, followed by LED array 2.
At 0, light corresponding to the print information is irradiated, and the portion that is hit by the light becomes conductive and loses charge, so that the print information is sequentially recorded on the photosensitive belt 10 as an electrostatic latent image. When the toner reaches the developing device 21, the positively charged toner is attracted to the negative charge on the photosensitive belt 10 by the magnet roll 21a in contact with the photosensitive belt 10, and the latent image is visualized. In this way, latent images are recorded one after another on the traveling photosensitive belt 10, and the latent images are visualized to form a toner image for one line.
When the toner image for a row faces a predetermined position on the paper 11 to be printed, the photosensitive belt 10 is activated by the belt start/stop means.
stops.

Next, the transfer device 23 charges the paper 11 and moves in the direction of the arrow (c) to press the paper 11 against the photosensitive belt 10 using the photosensitive belt guide 22 as a support, thereby transferring the toner image on the photosensitive belt 10. The image is electrostatically transferred onto the paper 11.

When the transfer of one line is completed in this way, the paper 11 is sent by the heat roller 24 and the bail roller 29, and the photosensitive belt 10 is started and runs again, repeating the above operation and printing information one after another. The images are transferred to the paper 11 line by line.

On the other hand, the paper 11 sent after printing is transferred to the heat roller 24.
By heating the paper 11, the toner, that is, the transferred image, is fixed.

In the electrophotographic printer with the above configuration, the width of the LED 7 ray 20 is only the width of the photosensitive bell (10), and the number of LEDs can be configured within, for example, several tens, resulting in significant downsizing.
and cost reduction.

In addition to the above-mentioned LED array 20, the static elimination lamp 1
7. The parts of the cleaner 18, one corona discharger, and the developing device 21 only need to be made to correspond to the width of the photosensitive belt 10, which is different from the conventional photosensitive drum system, which requires parts corresponding to the width of the paper. In addition, since the photoreceptor itself is belt-shaped, it is significantly smaller than the conventional photoreceptor drum system.

Further, a disadvantage of electrophotography is that it requires periodic replacement of many parts such as the photoreceptor and developing device, and maintenance costs are generally high due to these replacements.However, in the present invention, the photoreceptor belt 10 The regular replacement parts, such as the developing device 21, are small and inexpensive, significantly reducing maintenance costs.

In the embodiment, an LED array was used as the exposure means, but the exposure means is not limited to this, and means using a laser beam, means using a liquid crystal shutter, etc. may also be used.

[Effects of the Invention 1 As explained above, according to the present invention, an endless photosensitive belt that can run in a direction perpendicular to the paper feeding direction is provided,
A latent image is formed on this running photosensitive belt, it is visualized, and after the photosensitive belt has stopped running, it is transferred to paper by a transfer means, so it has various excellent features such as: be effective.

(i) Since the exposure means for forming a latent image on the photosensitive belt in accordance with the print information only needs to correspond to the width of the photosensitive belt, this exposure means can be significantly downsized and inexpensive.

(ii) With the conventional photosensitive drum method, in which a latent image is formed simultaneously over the entire width of the paper, it is difficult to increase the number of recorded dots at a high density. It is relatively easy to achieve this, and the present invention can easily realize even higher density printing.

(iii) Compared to the photosensitive drum system, the photosensitive belt is smaller, and the charging device, exposure means, developing means, toner removal means, etc. are all required for the width of the photosensitive belt, so these parts are smaller and cheaper. become.

Therefore, the entire device can be significantly downsized and inexpensive.

(iv) Since the photosensitive belt, developing device, etc. that require periodic replacement are also cheaper, maintenance costs are significantly reduced.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing a main part of the internal structure of an electrophotographic printer according to an embodiment of the present invention, and FIG. 2 is a schematic side view of a conventional electrophotographic printer. 10... Photosensitive belt, 11... Paper, 16... Belt driving means, 19... Corona discharger (charging device),
20...LED7 Ray (exposure means), 21...Developer, 23...Transfer means, 24...Heat roller (fixer).

Claims (1)

[Scope of Claims] A photosensitive belt formed by applying a photoconductive material to the surface of an endless belt base made of metal or conductive plastic; and the photosensitive belt is placed close to paper in a direction perpendicular to the feeding direction of the paper. a belt drive means for causing the photoreceptor belt to run; an exposure means for irradiating the photoreceptor belt with light corresponding to print information to record the print information as an electrostatic latent image on the photoreceptor belt; and a latent image is formed. a developing means for making the latent image visible by depositing a developer on the photosensitive belt; , an electrophotographic system comprising: a belt start/stop control means for correctly stopping or starting the photosensitive belt; and a transfer means for transferring the toner image on the photosensitive belt stopped at a predetermined position onto a sheet of paper. printer.