JP2801844B2 - Image forming device - Google Patents

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 an electrophotographic printer.

[0002]

2. Description of the Related Art Recently, with the development of information processing device technology and communication technology, a small and inexpensive electrophotographic type capable of outputting a large amount of arbitrary Chinese characters and figures on plain paper at high speed and with high quality. A printer has been requested. In order to meet this demand, an electrophotographic printer using an image forming apparatus in which a plurality of light emitting diode elements are linearly arranged and mounted on one main surface of an electrically insulating substrate as a light source of the printer has been reduced in size and resolution. It has been proposed as one.

An image forming apparatus used in this conventional electrophotographic printer generally has a lens plate made of a resin such as polycarbonate having a plurality of lenses linearly arranged and supported on a support at predetermined intervals, and a plurality of lenses. A base plate made of aluminum oxide sintered body, glass, etc., in which the light emitting diode element arrays of the above are linearly arranged and mounted, is fixed together so that each lens and each light emitting diode element array correspond one to one. It has a structure and is arranged inside a transparent cylindrical body with a photoreceptor film adhered on the outer surface, and the light emitting diodes of each light emitting diode element array selectively emit light corresponding to external electric signals At the same time, the light emitted from each of the light emitting diode elements is imaged on a photosensitive film adhered to the outer surface of the transparent cylindrical body via a lens, thereby forming a latent image on the photosensitive film. By doing so, it functions as an image forming apparatus.

Incidentally, the light emitting diode element array which is linearly arranged and mounted on the base plate generally has 64 light emitting diode elements linearly arranged inside thereof, and is a B4 size image forming apparatus. In this case, the light emitting diode element array is mounted on the base plate such that 32 of the light emitting diode element arrays correspond to the respective lenses on a one-to-one basis.

Further, when the positions of the respective lenses supported by the lens plate and the respective light emitting diode element arrays mounted on the base plate are displaced, the image formed on the surface of the photoreceptor becomes blurred, white stripes, or black. Since a streak or the like cannot be formed to form a clear and accurate latent image, each lens and each light emitting diode element array are aligned with extremely high precision.

[0006]

However, in this conventional image forming apparatus, a lens plate made of a resin such as polycarbonate for supporting a lens and an aluminum oxide sintered body or glass on which a light emitting diode element array is mounted are mounted. The thermal expansion coefficients of the base plates made of 1.9 × 10 ⁻⁵ / ° C. and 4.0 to 7.5 × 10 ⁻⁶ / ° C., respectively, are significantly different. When placed inside a transparent tubular body and used as a light source of an electrophotographic printer, when heat is applied to both the lens plate and the base plate due to the high temperature inside the transparent tubular body, The lens plate expands more thermally than the base plate, resulting in the lens supported by the lens plate and the light emitting diode element mounted on the base plate Misaligned between the ray, it had the disadvantage that it is impossible to form a clear and accurate latent image on the photoreceptor film.

[0007]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned drawbacks. It is an object of the present invention to accurately irradiate light emitted from a light-emitting diode element onto a photosensitive film through a lens so that the photosensitive film has high image quality. An object of the present invention is to provide an image forming apparatus capable of forming a latent image.

[0008]

SUMMARY OF THE INVENTION The present invention is arranged inside a transparent cylindrical body having a photoreceptor film adhered to an outer surface thereof, and irradiates the photoreceptor film with light from the inside of the transparent cylindrical body. An image forming apparatus for forming a latent image on a photoreceptor film, comprising a lens plate having a plurality of lenses linearly arranged and supported at predetermined intervals, and a large number of image element arrays being linearly arranged and mounted. A base plate, and a spacer for fixing the lens plate and the base plate together so that each lens and each image element array correspond to each other on a one-to-one basis. The thermal expansion coefficients of the lens plate, the base plate and the spacer are -30. It is characterized in that it is −2 to 3 × 10 ⁻⁶ / ° C. in a temperature range of １００100 ° C.

[0009]

According to the image forming apparatus of the present invention, the coefficients of thermal expansion of the lens plate supporting the lens, the base plate on which the image element array is mounted, and the spacer for positioning the lens plate and the base plate are set to -30 to -1.
The temperature was set to -2 to 3 × 10 ⁻⁶ / ° C. in the temperature range of 00 ° C., and almost no thermal expansion or contraction occurred. Therefore, when used as a light source for an electrophotographic printer, heat was applied to the lens plate, base plate and spacer. Are hardly expanded and contracted even when the image is applied. As a result, there is no displacement between each lens and each image element array, and there is also a variation in the distance between the photosensitive film and the lens. There is nothing to do. Therefore, in this image forming apparatus, the center of each lens is always positioned at the center of the light emitting diode element array, and the light emitted by the light emitting diode elements of each light emitting diode element array can be satisfactorily irradiated over the entire width of the photosensitive film. Thus, a clear and accurate latent image can be formed on the photoreceptor film.

[0010]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 and 2 show an embodiment of the image forming apparatus of the present invention, wherein 1 is a base plate, 2 is a lens plate, 3 is a spacer, 4 is a light emitting diode element array, and 5 is a lens.

The base plate 1 is made of an electrically insulating material, such as carbon fiber reinforced liquid crystal polymer, having a thermal expansion coefficient of -2 to 3 × 10 ⁻⁶ / ° C. in a temperature range of −30 to 100 ° C. and hardly thermally expanding and contracting. A plurality of light emitting diode element arrays 4 are linearly arranged and mounted on the upper surface.

The base plate 1 functions as a support member for supporting the light emitting diode element array 4, and is manufactured by adopting, for example, an injection molding method so that the injection flow direction coincides with the arrangement of the light emitting diode element array 4. Have been.

The light-emitting diode element array 4 arranged and mounted on the base plate 1 comprises a plurality of light-emitting diode elements 4a, and the light-emitting diode elements 4a individually and selectively emit light in response to an external electric signal. Then, the emitted light is applied to a photosensitive film 6b adhered to the outer surface of a transparent cylindrical body 6a described later to form a latent image for forming an image on the photosensitive film 6b.

The light emitting diode element 4a is made of GaAsP, Ga
P-based light-emitting diodes are used.For example, in the case of GaAsP-based light-emitting diodes, a GaAs substrate is first heated to a high temperature in a furnace, and AsH ₃ (arsine), PH ₃ (phosphine), and Ga (gallium) are used. ) Is brought into contact with a gas containing an appropriate amount of GaAsP (gallium-arsenide-phosphorus) single crystal on the substrate surface, and then Si ₃ O 4 is grown on the GaAsP single crystal surface.
An N ₄ (silicon nitride) film with a window is deposited, and the window is exposed to a gas of Zn (zinc).
Zn is diffused into a part of the single crystal to form a p-type semiconductor, and pn
It is formed by having a bond.

In the case of a B4 size electrophotographic printer, the number of the light emitting diode elements 4a is 2048 (8 per 1 mm).
) Are arranged in a straight line.Specifically, by arranging 32 light emitting diode element arrays 4 each having 64 light emitting diode elements 4a as one unit, 2048 light emitting diode elements 4a Are arranged on the base plate 1.

A base plate 1 on which the light emitting diode element array 4 is mounted is provided with a lens plate 2 at a predetermined distance above the base plate 1, and a plurality of holes 2a are formed in the lens plate 2 in a straight line. The lenses 5 are arrayed and fixed so as to cover the holes 2a via an adhesive such as resin.

The lens plate 2 includes a plurality of lenses 5
Acts as a support member for supporting the
Reference numeral 2a functions to transmit light emitted from each light emitting diode element 4a of the light emitting diode element array 4 to the photosensitive film 6b side.

The lens plate 2 includes a light emitting diode element array 4 made of, for example, a carbon fiber reinforced liquid crystal polymer.
Is the same as the base plate 1 on which
It is formed of a material of -2 to 3 × 10 ^-6 / ° C in a temperature range of 30 to 100 ° C, and has a lens plate 2 and a base plate.
1 has a thermal expansion coefficient of −2 to 3 × 10 ⁻⁶ / ° C. in a temperature range of −30 to 100 ° C. and hardly undergoes thermal expansion or contraction. And the lens supported by the lens plate 2 even when heat is applied to both the lens plate 2 and the base plate 1.
There is no displacement between the light emitting diode element 4 and the light emitting diode element array 4 arranged and mounted on the base plate 1, and as a result, light emitted from each light emitting diode element 4a is transmitted through the lens 5 to the photosensitive film. An accurate and clear image is formed on the photoconductor film 6b, and a high-quality latent image can be formed on the photoconductor film 6b.

Each lens 5 supported by the lens plate 2 has a function of irradiating the photosensitive film 6b with light emitted from each light emitting diode element 4a, and is made of a transparent resin such as acrylic resin or polycarbonate resin, glass or the like. A lens formed of a transparent inorganic material is preferably used.

Each of the lenses 5 is linearly bonded to the lens plate 2 at predetermined intervals by bonding a part of the outer surface of the lens 5 to the lens plate 2 via an adhesive such as a resin.

Further, the base plate 1 on which the light emitting diode element array 4 is mounted and the lens plate 2 on which the lens 5 is supported are fixed to the spacers 3 so that each light emitting diode element array 4 and each lens 5 are fixed. Are provided so as to correspond one-to-one with a predetermined distance.

The spacer 3 has a first reference surface on its top.
3a has a second reference surface 3b at the bottom, and the spacer 3
Each light emitting diode element array 4 and each lens 5 are fixed by abutting and fixing the outer peripheral portion of the lower surface of the lens plate 2 to the first reference surface 3a of the base plate 1 and the outer peripheral portion of the upper surface of the base plate 1 to the second reference surface 3b of the spacer 3. 1 to 1 with a predetermined distance between
It corresponds to.

The spacer 3 is made of, for example, a carbon fiber reinforced liquid crystal polymer having a coefficient of thermal expansion of -30 to 100.degree.
It is made of a material that hardly thermally expands and contracts in the temperature range of -2 to 3 × 10 ⁻⁶ / ° C., so that when it is used as a light source of an electrophotographic printer, heat is applied to the spacer 3. The distance between the lens 5 and the photoreceptor film 6b is always constant, and the light emitted from each light emitting diode element 4a is
Accurately and sharply irradiate the entire width of the photoreceptor film 6b through
A high-quality latent image can be formed on the photoconductor film 6b.

Thus, according to the image forming apparatus of the present invention, the image forming apparatus is disposed inside the transparent cylindrical body 6a having the photoreceptor film 6b adhered to the outer surface, and is linearly mounted on the base plate 1. A predetermined power is applied to each light emitting diode element 4a of the light emitting diode element array 4, and each light emitting diode element 4a
Are individually and selectively emitted, and the light emitted by the respective light emitting diode elements 4a is imaged on the photosensitive film 6b via the lens 5 to form a predetermined latent image on the photosensitive film 6b, thereby forming an image. Functions as a device.

It should be noted that the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the scope of the present invention. For example, in the above-described embodiment, the base plate 1 and the lens plate 2 And each of the spacers 3 is formed of a glass fiber reinforced liquid crystal polymer, which has a thermal expansion coefficient of -2 to 3 × 10 ^-6 /
It may be formed of another material having a temperature of ° C.

The transparent cylindrical body 6a having the photoreceptor film 6b on the outer surface is made of a material having a thermal expansion coefficient of -2 to 3 × 10 ^-6 / ° C. in a temperature range of -30 to 100 ° C. Once formed, when operated as an electrophotographic printer, the transparent tubular body 6a is almost thermally expanded, even if heat is applied to the transparent tubular body 6a.
As a result, the distance between the lens 5 and the photoreceptor film 6b becomes constant, and the light emitted from each light emitting diode element 4a is accurately and clearly radiated to the entire width of the photoreceptor film 6b via the lens 5. Thus, a high-quality latent image can be formed by the photoconductor film 6b.

Further, a light emitting diode element array between and adjacent to the base plate 1 and the lens plate 2
If a light-shielding plate 8 is provided between the light-emitting diodes 4, light emitted from the light-emitting diode elements 4a of each light-emitting diode element array 4 will leak to the adjacent light-emitting diode element array 4 even if the light is leaked by the light-shielding plate 8. As a result, light emitted from the light emitting diode elements 4a of each light emitting diode element array 4 is irradiated and imaged only on the photosensitive film 6b via the corresponding lens 5 on a one-to-one basis, and is formed on the photosensitive film 6b. No blur is caused by unnecessary light irradiation, and an extremely clear latent image can be formed. Therefore, it is preferable to arrange a light shielding plate 8 between the base plate 1 and the lens plate 2 and between the adjacent light emitting diode element arrays 4.

[0028]

According to the image forming apparatus of the present invention, the thermal expansion coefficient of each of the lens plate supporting the lens, the base plate on which the image element array is mounted, and the spacer for positioning the lens plate and the base plate is reduced by -3.
When used as a light source for an electrophotographic printer, the temperature was set to -2 to 3 × 10 ⁻⁶ / ° C. in a temperature range of 0 to 100 ° C., and almost no thermal expansion or contraction occurred.
Even when heat is applied to the base plate and the spacer, each of them hardly expands and contracts. As a result, there is no displacement between each lens and each image element array. There will be no variation in the distance. Therefore, in this image forming apparatus, the center of each lens is always positioned at the center of the light emitting diode element array, and the light emitted by the light emitting diode elements of each light emitting diode element array can be satisfactorily irradiated over the entire width of the photosensitive film. Thus, a clear and accurate latent image can be formed on the photoreceptor film.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating an embodiment of an image forming apparatus according to the present invention.

FIG. 2 is a longitudinal sectional view of the image forming apparatus shown in FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Base plate 2 ... Lens plate 3 ... Spacer 4 ... Light emitting diode element array 4a ... Light emitting diode element 5 ... Lens 6a ... Transparent cylindrical body 6b ... Photoreceptor film

──────────────────────────────────────────────────続 き Continuation of the front page (51) Int.Cl. ⁶ Identification symbol FI H01L 33/00 (56) References JP-A-5-307140 (JP, A) JP-A-4-336518 (JP, A) JP-A-2-286358 (JP, A) JP-A-2-134260 (JP, A) JP-A-1-264469 (JP, A) JP-A-56-80958 (JP, A) (JP, U) Japanese Utility Model 63-169754 (JP, U) (58) Fields investigated (Int. Cl. ⁶ , DB name) B41J 2/44 B41J 2/45 B41J 2/455 G02B 7/02 G02B 27 / 18 H01L 33/00 G03G 15/04

Claims (1)

(57) [Claims] 1. A photoreceptor film is disposed inside a transparent cylindrical body having a photoreceptor film adhered to an outer surface thereof, and light is applied to the photoreceptor film from inside the transparent cylindrical body to form a latent image on the photoreceptor film. An image forming apparatus for forming, a lens plate having a plurality of lenses linearly arranged and supported at predetermined intervals, a base plate on which a large number of image element arrays are linearly arranged and mounted, and the lens plate And a spacer for fixing the lens and the image element array together so that each lens and each image element array correspond to each other in a one-to-one correspondence. An image forming apparatus, wherein the temperature is −2 to 3 × 10 ⁻⁶ / ° C.