JPH06320792A - Image forming device - Google Patents

Abstract

(57) [Summary] [Object] To provide an image forming apparatus capable of effectively preventing unnecessary light from irradiating a photoconductor and forming a latent image with high image quality on the photoconductor. . A light emitting diode element array (2) having a large number of light emitting diode elements (2a) linearly arranged and mounted in a housing (4) in which a lens array (3) is mounted is arranged such that each light emitting diode element (2a) faces the lens array (3). An image forming apparatus fixedly housed in the housing 4
An antireflection portion 4a is formed on the inner surface of the.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus used as a light source of a recording device such as an electrophotographic printer.

[0002]

2. Description of the Related Art Recently, with the progress of information processing technology and communication technology, a compact and inexpensive electrophotographic printer capable of outputting a large amount of arbitrary kanji and figures on plain paper at high speed and high quality. Is required. Therefore, in order to meet this demand, an electrophotographic printer using an optical printer head in which a plurality of light emitting diode elements (LEDs) are linearly mounted on one main surface of an electrically insulating substrate as a light source of a printer is small. , Has been proposed as a high resolution one.

An optical printer head as an image forming apparatus used in this conventional electrophotographic printer is usually
As shown in FIG. 2, a light emitting diode element array 13 comprising a plurality of light emitting diode elements 13a on an electrically insulating substrate 12
Is composed of a base plate 11 in which a plurality of rods are arranged linearly, a lens array 14 in which a large number of rod-shaped self-focusing lenses 16 are linearly arranged in two rows on a frame body 15, and a housing 17 made of polycarbonate resin or the like. The base plate 11 and the lens array 14 are fixed to the housing 17 with an adhesive so that each light emitting diode element 13a is located on the optical axis of each rod-shaped self-focusing lens 16.

In the optical printer head as the image forming apparatus, each light emitting diode element 13a of the light emitting diode element array 13 is caused to selectively emit light in response to an external electric signal, and each light emitting diode element 13a emits light. The formed light is imaged on the surface of the external photoconductor 18 via the lens array 14, and a latent image is formed on the photoconductor 18 to function as an image forming apparatus.

[0005]

However, in this conventional image forming apparatus, the aperture angle of the lens array 14 is about 20 degrees in order to allow the lens array 14 to capture a large amount of light emitted from the light emitting diode element 13a. Due to the large size and the fact that the inner surface of the housing 17 is a flat surface and easily reflects light, each of the light emitting diode elements 13a is caused to selectively emit light, and the emitted light is externally exposed through the lens array 14. When an image is formed on the surface of the body 18 to form a latent image on the photoconductor 18, a part of the light emitted by each light emitting diode element 13a is irradiated to the inner surface of the housing 17 and scattered, and this enters the lens array 14. As a result, the photosensitive member is irradiated with unnecessary light through the lens array, and there is a drawback that an accurate and clear latent image cannot be formed on the photosensitive member.

[0006]

SUMMARY OF THE INVENTION The present invention has been devised in view of the above-mentioned drawbacks, and it is an object of the present invention to effectively prevent unnecessary light from irradiating the photoconductor and form a latent image on the photoconductor with high image quality. An object of the present invention is to provide an image forming apparatus capable of performing the above.

[0007]

SUMMARY OF THE INVENTION According to the present invention, a light emitting diode element array having a large number of light emitting diode elements linearly arranged and mounted in a housing to which a lens array is attached is provided. An image forming apparatus, which is fixedly housed so as to be opposed to each other, is characterized in that an antireflection portion is formed on an inner surface of the housing.

[0008]

According to the image forming apparatus of the present invention, since the antireflection portion is formed on the inner surface of the housing, each light emitting diode element is caused to selectively emit light, and the emitted light is passed through the lens array. When an image is formed on the surface of an external photoconductor to form a latent image on the photoconductor, a part of the light emitted from each light emitting diode element is applied to the inner surface of the housing, and even if scattered, the scattered light is an antireflection portion. Effectively prevents the light from entering the lens array, so that the lens array satisfactorily irradiates only the direct light from each light emitting diode element excluding the scattered light onto the photoconductor, and the photoconductor has a clear and accurate latent image. It is possible to form an image.

[0009]

The present invention will now be described in detail with reference to the accompanying drawings. FIG. 1 shows an embodiment of an optical printer head as an image forming apparatus of the present invention, in which 1 is a base plate, 2 is a light emitting diode element array, 3 is a lens array, and 4 is a housing.

The base plate 1 is made of an electrically insulating material such as ceramic, glass or glass epoxy, and a plurality of light emitting diode element arrays 2 are linearly mounted on the upper surface thereof.

The pace plate 1 functions as a support member for supporting the light emitting diode element array 2, and when it is made of, for example, a ceramic of an aluminum oxide sintered body, alumina (Al ₂ O ₃ ) and silica ( SiO ₂ ), calcia (CaO), magnesia (MgO), etc.A suitable organic solvent is added to the raw material powder, and the solvent is mixed together to form a slurry and this is adopted by the well-known doctor blade method or calendar roll method. To obtain a ceramic green sheet (ceramic green sheet), and thereafter, the ceramic green sheet is punched into a predetermined shape and fired at a high temperature (about 1600 ° C.).

The light emitting diode element array 2 mounted on the base plate 1 is composed of a plurality of light emitting diode elements 2a, and the light emitting diode elements 2a selectively emit light in response to an external electric signal, By irradiating the surface of the photoconductor 5 with the emitted light, a latent image for forming an image is formed on the photoconductor 5.

The light emitting diode element 2a is made of GaAsP.
-Based, GaP-based light-emitting diodes are used, for example, GaAs
In the case of P-based light-emitting diodes, as well as heating to a high temperature the GaAs substrate at furnace First AsH ₃ and (arsine) PH
A gas containing an appropriate amount of ₃ (phosphine) and Ga (gallium) is contacted to grow an n-type semiconductor GaAsP (gallium-arsenic-phosphorus) single crystal on the substrate surface, and then a GaAsP single crystal surface is grown.
A window film of Si ₃ N ₄ (silicon nitride) is deposited, and Zn (zinc) gas is exposed to the window part to remove Ga of n-type semiconductor.
It is formed by diffusing Zn into a part of an AsP single crystal to form a p-type semiconductor and having a pn junction.

In the case of the B4 size optical printer head, 2048 (8 per 1 mm) light emitting diode elements 2a are linearly arranged. Specifically, 64 light emitting diodes are set as one unit. By arranging 32 light emitting diode arrays 2 linearly, 2048 light emitting diode elements 2a are arranged on the base plate 1.

Further, the light emitting diode element 2a is provided with a lens array 3 at a predetermined distance above the light emitting diode element 2a. The lens array 3 has a function of irradiating the surface of the photoconductor 5 with the light emitted from each light emitting diode element 2a. Do

The lens array 3 is made of glass in a frame 6,
Rod-shaped self-focusing lens made of synthetic resin
It has a structure in which a large number of 7 are arranged linearly in two rows.
The rod-shaped self-focusing lens 7 is sandwiched between the ABS resin or FRP plate and each self-focusing lens 7 between the ABS resin or FRP plate and each self-focusing lens 7 by sandwiching the rod-shaped self-focusing lens 7 in two rows. It is manufactured by curing and adhering the frame body 6 and the self-focusing lens 7 with a silicone resin.

The base plate 1 and the lens array 3 on which the light emitting diode element array 2 is mounted have a fixed distance between them, and the optical axis of each self-focusing lens 7 of the lens array 3 is the light emitting diode element array. 2 is fixed to a housing 4 made of resin so as to be above each light emitting diode element 2a.

The base plate 1 and the lens array 3 are fixed to the housing 4 by mounting the light emitting diode element array 2 inside the lower part of the housing 4.
1 and the lens array 3 are bonded and fixed to the upper part of the lens array 3 with an adhesive made of epoxy resin.

The housing 4 to which the lens array 3 and the like are fixed is made of polycarbonate resin, and is formed into a predetermined shape by adopting a conventionally known resin molding method.

Further, the housing 4 has an antireflection portion 4a formed on the inner surface thereof, and the light emitted from each light emitting diode element 2a is imaged on the surface of the external photoconductor 5 through the lens array 3 to form the photoconductor 5 When a latent image is formed on the inner surface of the housing 4, a part of the light emitted from each light emitting diode element 2a is applied to the inner surface of the housing 4, and even if the light is scattered, the scattered light is the antireflection portion.
4a effectively prevents the light from entering the lens array 3, and as a result, the lens array 3 satisfactorily irradiates only the direct light from each light emitting diode element 2a excluding the scattered light onto the photoconductor 5 and makes the photoconductor 5 clear. Therefore, it is possible to form an accurate latent image.

The antireflection portion 4a on the inner surface of the housing 4 is formed by etching or sandblasting the inner surface of the housing 4 so that the inner surface of the housing 4 has a center line average roughness (Ra) of 0.
The surface area of the inner surface of the housing 4 is 0.01 mm when it is formed by forming a rough surface in the range of 1 mm ≤ Ra ≤ 2 mm, or when the housing 4 is formed into a predetermined shape by adopting a conventionally known resin molding method. ² to a small protrusion and depth 0.1mm to 2mm of 10 mm ^2, it is formed on the inner surface of the housing 4 by be formed at the same number of grooves of width 0.1mm to 1 mm.

Thus, according to the image forming apparatus of the present invention, the plurality of light emitting diode elements 2a linearly arranged on the base plate 1 are caused to individually and selectively emit light in response to an external electric signal, and the emitted light is emitted. By irradiating the photoconductor 5 through the lens array 3 with the light, it functions as an image forming apparatus.

The present invention is not limited to the above-mentioned embodiments, but various modifications can be made without departing from the scope of the present invention.

[0024]

According to the image forming apparatus of the present invention, since the antireflection portion is formed on the inner surface of the housing, each light emitting diode element is caused to selectively emit light, and the emitted light is lens array. When a latent image is formed on the photoconductor by forming an image on the external photoconductor surface via, the light emitted from each light emitting diode element is partly irradiated to the inner surface of the housing, and even if scattered, the scattered light is The antireflection portion effectively prevents the lens array from entering the lens array, and as a result, the lens array satisfactorily irradiates only the direct light from each light emitting diode element excluding the scattered light onto the photoconductor, and the photoconductor is clear and It is possible to form an accurate latent image.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of an optical printer head as an image forming apparatus of the present invention.

FIG. 2 is a sectional view of a conventional optical printer head.

[Explanation of symbols]

 1 ... Base plate 2 ... Light emitting diode array 2a ... Light emitting diode 3 ... Lens array 4 ... Housing 4a ... Antireflection portion 6 ... Frame 7 ... ..Bar-shaped lenses

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display location H04N 1/036 A 8721-5C

Claims (1)

[Claims] 1. A light-emitting diode element array in which a large number of light-emitting diode elements are linearly arranged and mounted in a housing to which a lens array is attached, is fixedly housed so that each light-emitting diode element is arranged to face the lens array. An image forming apparatus comprising: an antireflection portion formed on an inner surface of the housing.