JPH0426870A - electronic photo printer - Google Patents

Abstract

PURPOSE:To prevent the deterioration of the performance of a head caused by the contamination by toner and to improve reliability by causing a cleaning means to clean the light projection surface of the image-formation optical system of an exposing means. CONSTITUTION:A head cleaner 13 is arranged at the end of a photosensitive drum 1. The cleaner 13 is obtained by providing a brush 12 on a base 11. When the exposing head 2 passes the position of the cleaner 13 in the case of the scanning action of the head 2, the tip part of the brush 12 contacts with the tip part of an image-formation lens 33 to remove a foreign matter such as toner powder stuck to the surface of the projection surface 39. Thus, the projection surface of the exposing head is always cleaned and an electrophotographic printer where lowering of light quantity caused by the contamination is not found and which has high reliability is accomplished.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to an electrophotographic printer.

[Conventional technology]

In conventional electrophotographic printers, a method is widely used in which a laser beam emitted by a laser light source is deflected using a rotating polygon mirror, and the laser beam is modulated without being scanned over the photoconductor to expose a predetermined position (for example, Japanese Patent Publication No. 63-21081
5).

On the other hand, using an exposure head in which a plurality of LED elements are arranged in a straight line, an imaging optical system performs image exposure of the LED element array, and while continuously rotating the photoreceptor, the exposure head is It may also be configured to scan. According to this configuration, the light source and the photoreceptor can be placed close to each other, making it possible to downsize the device.

[Invention or problem to be solved]

In the above configuration, optical elements such as lenses are arranged closer to the photoreceptor than in a conventional structure using a rotating polygon mirror.

Since images are formed by adhering powdered toner to the surface of the photoreceptor, the optical elements are dyed with the toner, causing a problem of reduced light intensity.

An object of the present invention is to solve this problem, prevent head performance from deteriorating due to toner contamination, and realize a highly reliable electrophotographic printer.

[Means to solve the problem]

The electrophotographic printer of the present invention includes a photoreceptor made of a photoconductor, an exposure means, and a developing means cleaning means, and the electrostatic latent image is formed on the charged photoreceptor by the exposure means; In an electrophotographic printer in which an image is visualized by a developing means, the exposure means has a light emitting element and an imaging optical system, scans the photoreceptor, and performs image exposure at a predetermined position on the photoreceptor; It is characterized in that the cleaning means is configured to clean the light exit surface of the imaging optical system of the exposure means.

〔Example〕

Next, the present invention will be explained based on examples. FIG. 2 is a sectional view of a printer showing an embodiment of the present invention. An exposure head 2 serving as an exposure means, a charging device 3,
A developing device 4, a cleaner device 5, and a transfer device 6 are arranged.

Furthermore, a head cleaner 13, which is a cleaning means, is provided at the end of the photosensitive drum 1 in the direction toward the surface of the drawing. The charging device 3 is a roller made of conductive rubber, which is brought into contact with the photosensitive drum 1 while applying a potential to perform contact charging. The developing device 4 rubs the charged powder toner on the photoreceptor tram 1, adheres the toner in accordance with the electrostatic latent image, and visualizes this. The transfer device 6 is composed of a conductive roller, creates a potential difference between the metal tram of the photoreceptor tram 1, and directs the charged toner interposed between the metal tram and the photoreceptor drum 1 toward the recording paper, which is a recording medium, by static electricity. The toner image is transferred by suction and adhesion using force. The cleaner device 5 presses an elastic plate against the photoreceptor tram 1 to remove residual toner after transfer. Furthermore, it is comprised of a paper feeding device 7 that stores recording paper as a recording medium, a fixing device 9 that heat-fixes toner on the recording paper, and a paper discharge tray 8 that stores the recording paper after printing.

FIG. 3 shows the structure of the exposure head which is the exposure means. The exposure head 2 includes a light emitting substrate 36, a carriage 31, an imaging lens 33, and a cover (not shown). The carriage 31 has a structure in which a bearing 35 is integrated and is guided by a guide shaft, which will be described later. As shown in FIG. 4, the light emitting board 36 has an LED chip 42 having an LED element row 44 consisting of 128 LED elements that can be independently lit and driven on a board 43 provided with a wiring pattern. Driver IC41 is installed and wired. L
The ED element rows 44 are arranged in a direction perpendicular to the axis of the photoreceptor drum 1. This LED light is imaged onto the outer peripheral surface of the photoreceptor drum 1 by the imaging lens 33. The photosensitive drum 1 has a cylindrical shape with a diameter of 30 mm, and the imaging lens 33 is composed of an array of gradient index rod lenses 37.

As a result, an image of each LED element of the LED element array 34 is formed on the surface of the photoreceptor.

The relationship among the exposure head 2, photosensitive drum 1, guide shaft 25, and head cleaner 13 is shown in FIG.

The exposure head 2 spirally scans over the photoreceptor tram,
128 L on photoconductor tram 1 in one exposure scanning operation.
Exposure is performed in a stripe shape with a predetermined width determined by the width of the ED element array. The exposure head 2 is guided by a guide shaft 25,
The photoreceptor tram 1 is scanned while maintaining a constant distance from the outer periphery of the photoreceptor tram, and a carriage drive wire 23 is driven by a motor 24 to cause it to reciprocate. A wiring 22 for driving a light source is provided at the exposure throat 2. Head 2 is arrow B
When moving in the lj direction of the photoconductor tram 1, the photoconductor tram 1 is moved in the rotational direction at the same speed as the rotational speed of the arrow A in the pj direction.
The guide shaft 25 is formed into a spiral shape.

A head cleaner 13 is arranged at the end of the photoreceptor tram. This is a swing 2 provided on a base 11. Head cleaner 1 during scanning operation of exposure head 2
When passing through position 3, the tip of the brush 12 comes into contact with the tip of the imaging lens 33, and foreign matter such as toner powder adhering to the surface of the emission surface 39 is removed.

Next, the printing operation will be explained. While rotating the photosensitive drum 1, it is brought into contact with a charging device 3 to which a high voltage is applied, and the surface thereof is charged. Next, the exposure head 2 selectively removes the charge and forms an electrostatic latent image. That is, by scanning a curve along the guide shaft 25 while rotating the photoreceptor drum 1 in the direction of arrow A, the photoreceptor drum 1 is moved in a direction parallel to the photoreceptor drum axis relative to the photoreceptor drum 1. is scanned. The exposure head 2 exposes a stripe-shaped area with a width of about 10.1 mm on the photoreceptor drum 1 parallel to the drum axis. The outer peripheral speed of the photoreceptor drum 1 is constant rotation at 101 mn/s. The length of exposure in the circumferential direction on the photosensitive drum 1 made by the exposure head 2 is 101 mm, and the helical scanning operation is performed in a reciprocating motion in about 1 second. In other words, since the photoreceptor drum moves by a distance equal to the head's effective exposure length (10.1 mm) during one scanning operation, the next scanning operation of the exposure head 2 exposes the photoreceptor drum 1 without any gaps. I can do something.

The electrostatic latent image thus formed is developed by a well-known method as an electrophotographic process, transferred and fixed onto recording paper, and stored in the paper discharge tray 8.

In this configuration, the imaging lens 3 is
The light emitting surface 39 on the surface of the light emitting device 3 is constantly cleaned by the Herad cleaner 13, and problems such as a decrease in the light intensity due to adhesion of foreign matter do not occur.

A second embodiment is shown in FIG. The figure shows photoconductor tram 1.
Only the herad cleaner 16 is shown. In this embodiment, the head cleaner 16 consists of an elastic blade 15, and is connected to the exposure head 2.
During the scanning operation, the elastic bullet tip 14 touches the imaging lens 3.
It comes into contact with the surface of No. 3 and removes foreign matter adhering to the surface.

Yet another embodiment is shown in FIG. A head cleaner 18 consisting of brushes 17 with radially flocked bristles is provided on the outer periphery of the end of the photosensitive drum 1. During the exposure scanning operation of the exposure head 2, the rotating operation of the photoreceptor 1 and the scanning operation of the exposure head 2 clean the surface of the exit surface 39 of the imaging lens 33 passing through. Other components, operations, etc. are the same as those in the first embodiment, and their explanations will be omitted.

〔Effect of the invention〕

According to the above configuration of the present invention, the exit surface of the exposure head is always kept clean, and a highly reliable electrophotographic printer can be realized without any decrease in light amount due to contamination.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing the structure of the peripheral portion of a photoreceptor, showing an embodiment of a printer equipped with a cleaning member according to the present invention. FIG. 2 is a sectional view of a printer showing an embodiment of the present invention. FIG. 3 is a diagram showing the configuration of an exposure head used in a printer showing an embodiment of the present invention. FIG. 4 is a diagram showing the configuration of a light emitting board used in a printer showing one embodiment of the present invention. FIG. 5 is a diagram showing the structure of a cleaning member showing another embodiment of the present invention. FIG. 6 is a diagram showing the structure of a cleaning member showing still another embodiment of the present invention. ]......Photoreceptor drum...Exposure head 36...Light emitting board 33...Imaging lens 39...Emission surface 13.16.18...Head cleaner 12.17...
... Brush 15 ...... Elastic blade Applicant Seiko Epson Co., Ltd. Agent Attorney Kizobe Suzuki (and others) Figure 3 36 Luminescence group - \ in No. 401

Claims (1)

[Scope of Claims] A photoreceptor made of a photoconductor, an exposure means, and a developing means, the charged photoreceptor is subjected to imagewise exposure by the exposure means to form an electrostatic latent image, and the developing means is used to develop the electrostatic latent image. An electrophotographic printer that generates an image has a light emitting element and an imaging optical system, scans the photoreceptor,
An electrophotographic printer comprising: the exposure means for performing imagewise exposure on a predetermined position on the photoreceptor; and a cleaning means for cleaning a light exit surface of the imaging optical system of the exposure means.