JPH08195855A - Image forming device - Google Patents

Abstract

(57) [Abstract] [Object] To provide an image forming apparatus capable of accurately irradiating light emitted from an image element array onto a surface of a photoconductor through a lens to form a latent image with high image quality on the photoconductor. It is in. A lens plate 3 in which a plurality of lenses 3a are linearly arranged and supported at predetermined intervals, and a plurality of image element arrays 2 in which a large number of image elements 2a are linearly arranged are linearly mounted. An image forming apparatus in which a base plate 1 and a lens 3a are fixed side by side so that each lens 3a and each image element array 2 are in a one-to-one correspondence with a spacer 4 interposed therebetween. Image element 2 located at
The electrode 8 of a is led out in the direction parallel to the arrangement direction of the image elements 2a, and the electrodes 8 of the other image elements 2a are led out in the direction perpendicular to the arrangement direction of the image elements 2a.

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 progress of information processing apparatus 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 image forming apparatus in which a plurality of light emitting diode elements as image elements are linearly arranged and mounted on one main surface of an electrically insulating substrate is used as a light source of the printer. It is proposed as a small size and high resolution type.

An image forming apparatus used in this conventional electrophotographic printer usually has a spacer, a lens plate made of a resin such as polycarbonate in which a plurality of lenses are linearly arranged and supported at a predetermined interval, and a large number of lenses. Each of the lenses and each light emitting diode element array includes a plurality of light emitting diode element arrays in which the light emitting diode elements of FIG. The light emitting diode elements of each light emitting diode element array are made to emit light selectively in response to an external electrical signal, and each light emitting diode element The emitted light is irradiated through the lens onto the surface of the external photoconductor to form an image, and a latent image is formed on the photoconductor. Functions as printer light source.

The light emitting diode element array linearly arranged and mounted on the base plate is generally composed of 64 light emitting diode elements linearly arranged therein, and is a B4 size electrophotographic printer. When used as a light source, the 32 light emitting diode element arrays are mounted on the base plate so that each of the 32 light emitting diode element arrays has a one-to-one correspondence with each lens.

Further, in the light emitting diode element array in which the plurality of light emitting diode elements are linearly arranged, the electrodes of the respective light emitting diode elements are all led out in a direction perpendicular to the arrangement direction of the light emitting diode elements. The light emission intensity of the device is uniform.

Further, when each lens supported by the lens plate and each light emitting diode element array mounted on the base plate are displaced from each other, the image formed on the surface of the photoconductor has a bleed, white or black streaks. Therefore, it is impossible to form a clear latent image that is clear and accurate, so that it is necessary to align each lens and each light emitting diode element array with extremely high accuracy.

[0007]

However, in this conventional image forming apparatus, there is a difference of about 0.2 mm in the focal length between the central portion and the outer peripheral portion of the lens. When the light emitting diode elements are made to selectively emit light and the light is applied to the surface of the photoconductor through the lens to form a latent image on the photoconductor, the light emitting diode elements arranged in the center of each light emitting diode element array are The emitted light passes through the central part of the lens and is applied to the photoconductor with a large amount of light, whereas the emitted light from the light emitting diode elements located at both ends of each light emitting diode element array when passing through the outer peripheral portion of the lens. The amount of light radiated on the surface of the photoconductor is disturbed thickly and the amount of light radiated on the photoconductor surface is reduced. As a result, the amount of light radiated on the photoconductor surface varies, forming a clear latent image without unevenness on the photoconductor. It had the disadvantage that can not be Rukoto.

[0008]

SUMMARY OF THE INVENTION The present invention has been devised in view of the above-mentioned drawbacks, and an object thereof is to accurately irradiate the photoconductor surface with light emitted from an image element array through a lens to form a latent image of high image quality on the photoconductor. An object of the present invention is to provide an image forming apparatus capable of forming an image.

[0009]

SUMMARY OF THE INVENTION According to the present invention, a lens plate having a plurality of lenses linearly arranged and supported at predetermined intervals, and a plurality of image element arrays in which a large number of image elements are linearly arranged are provided. Base plate mounted in a
Each lens and each image element array have one spacer with a spacer interposed therebetween.
In the image forming apparatus, which is fixed side by side so as to correspond to pair 1, the electrodes of the image elements located at both ends of each of the image element arrays are parallel to the arrangement direction of the image elements, and It is characterized in that the electrodes are led out in a direction perpendicular to the arrangement direction of the image elements.

[0010]

According to the image forming apparatus of the present invention, the electrodes of the image elements located at both ends of each image element array mounted on the base plate are parallel to the arrangement direction of the image elements, and The electrodes were led out in the direction perpendicular to the arrangement direction of the image elements, and the emission intensity of the image elements located at both ends was made stronger than the emission intensity of the other image elements. When light is emitted and the surface of the photoconductor is irradiated with the light through the lens to form a latent image, the light emitted by the image elements located at both ends of the image element array becomes thick when passing through the outer peripheral portion of the lens. Even if it is disturbed, the amount of light applied to the photoconductor is almost equal to the light applied to other image elements, and as a result,
Irradiation of light onto the surface of the photoconductor becomes uniform, and it becomes possible to form a latent image with extremely high image quality on the photoconductor.

[0011]

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

The base plate 1 is made of an electrically insulating material such as aluminum oxide sintered body, crystallized glass, quartz, or glass epoxy resin, and a plurality of light emitting diode element arrays 2 are linearly mounted on the upper surface of the base plate 1 to emit light. It serves to fix and support the diode element array 2.

When the base plate 1 is made of, for example, an aluminum oxide sintered body, alumina (Al ₂ O ₃ )
, Silica (SiO ₂ ), calcia (CaO), magnesia (MgO)
To obtain a ceramic green sheet (ceramic green sheet) by adding an appropriate organic solvent to the raw material powder such as and mixing it to form a slurry and adopting the conventionally known doctor blade method or calender roll method Then, 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 arranged and mounted on the base plate 1 is composed of a plurality of light emitting diode elements 2a, and the light emitting diode elements 2a individually and selectively emit light in response to an external electric signal. A latent image for forming an image is formed on the photoconductor P by irradiating the surface of the photoconductor P with the emitted light.

The light emitting diode element 2a is a GaAsP type, Ga
P-based light-emitting diodes are used, for example, in the case of a GaAsP-based light-emitting diodes, as well as heating to a high temperature the GaAs substrate at furnace First AsH ₃ and (arsine) PH ₃ and (Hosuhin) Ga (gallium ) Is contacted with a gas to grow a single crystal of n-type semiconductor GaAsP (gallium-arsenic-phosphorus) on the substrate surface, and then Si ₃ is grown on the GaAsP single crystal surface.
A windowed film of N ₄ (silicon nitride) is deposited, and Zn (zinc) gas is exposed to the window to form an n-type semiconductor GaAsP.
Zn is diffused into a part of the single crystal to form a p-type semiconductor, and pn
It is formed by providing a bond.

In the case of a B4 size optical printer head, the number of the light emitting diode elements 2a is 2048 (8 per 1 mm).
Are arranged linearly, and specifically, a light emitting diode element array in which 64 light emitting diode elements 2a are one unit
32 light emitting diode elements 2a are linearly arranged, and thus 2048 light emitting diode elements 2a are arranged and mounted on the base plate 1.

To mount the light emitting diode element array 2 on the base plate 1, a strip-shaped common wiring conductor 5 and a plurality of individual wiring conductors 6 are previously formed on the upper surface of the base plate 1 as shown in FIG. The common wiring conductor
This is performed by bonding the common electrode 7 of the light emitting diode element array 2 to 5 through a conductive material such as solder.

Further, the individual wiring conductors 6 deposited on the base plate 1 are provided with individual electrodes of each light emitting diode element 2a.
8 is connected via a bonding wire 9, whereby a predetermined electric power required for light emission is externally applied to each light emitting diode element 2a of the light emitting diode element array 2 through the common wiring conductor 5 and the individual wiring conductor 6. To be done.

The common wiring conductors 5 and the individual wiring conductors 6 deposited on the upper surface of the base plate 1 are made of, for example, a metal material such as aluminum, nickel or gold. Aluminum is vapor-deposited or sputtered on the base plate 1. It is applied to a thickness of 1.0 to 3.0 μm by thin film forming technology such as the above, and it is formed into a predetermined pattern by photolithography technology, and then nickel and gold are electroplated or electroless plated on this aluminum pattern. Is formed by sequentially depositing.

When an aluminum pattern is to be deposited on the base plate 1, if a layer made of titanium, chromium, or the like is deposited between the base plate 1 and the aluminum pattern to a thickness of 100 to 1000 angstroms, the two are bonded. The strength can be extremely strong. Therefore, it is preferable to provide a layer of titanium or chromium having a thickness of 100 to 1000 angstrom between the base plate 1 and the aluminum pattern.

Further, as shown in FIG. 4, in the light emitting diode element array 2, among the individual electrodes 8 of the light emitting diode element 2a, the individual electrodes 8a of the light emitting diode elements 2a located at both ends of the light emitting diode element array 2 are the light emitting diode elements. 2a
In the direction parallel to the arrangement direction of the, the individual electrodes 8b of the other light emitting diode elements 2a are led out in the direction perpendicular to the arrangement direction of the light emitting diode elements 2a, whereby the emission intensity of the light emitting diode elements 2a located at both ends Is stronger than the light emission intensity of the other light emitting diode elements 2a.

The base plate 1 on which the light emitting diode element array 2 is mounted is also provided with a lens plate 3 on the upper part thereof with a certain distance, and a plurality of holes are linearly arranged in the lens plate 3. The lens 3a is attached so as to cover the hole while being formed.

The lens plate 3 includes a plurality of lenses 3a.
Function as a supporting member for supporting the light emitting diode elements of the light emitting diode element array 2 at a predetermined interval.
The light emitted from 2a is transmitted to the lens 3a.

Further, each lens 3a supported by the lens plate 3 causes the light emitted from each emitting diode element 2a to pass through the photoconductor P.
A lens formed of a transparent resin such as an acrylic resin or a polycarbonate resin or a transparent inorganic material such as glass, which has the function of irradiating the surface, is preferably used.

Furthermore, the light emitting diode element array 2
Is mounted on the base plate 1 and a plurality of lenses 3a are supported by the lens plate 3
Each LED element array 2 and each lens 3a are arranged side by side by a predetermined distance so as to correspond one-to-one by being joined to each other.

The pair of spacers 4, 4 has a first alignment reference plane 4a at the upper portion thereof and a second alignment reference plane at the lower portion thereof.
Each of the spacers 4 and 4 has a first alignment reference surface 4a on which the lower surface of the lens plate 3 is abutted, and a second alignment reference surface 4b on which an outer peripheral portion of the upper surface of the base plate 1 is abutted and fixed. Diode element array 2 and each lens
It is designed to correspond exactly one-to-one with a predetermined distance from 3a. The pair of spacers 4, 4 are made of, for example, glass epoxy resin or the like.

Thus, according to the image forming apparatus of the present invention, each light emitting diode element 2a is individually selected by applying a predetermined power to each light emitting diode element 2a of the light emitting diode element array 2 arranged and mounted on the base plate 1. The light emitted from each light emitting diode element 2a is radiated and image-formed on the surface of the external photoconductor P through the lens 3a while functioning as a light source of the electrophotographic printer. In this case, the individual electrodes 8a of the light emitting diode elements 2a located at both ends of each light emitting diode element array 2 mounted on the base plate 1 are parallel to the arrangement direction of the light emitting diode elements 2a, and the other light emitting diode elements 2a The individual electrode 8b of is led out in the direction perpendicular to the arrangement direction of the light emitting diode elements 2a, and the light emitting intensity of the light emitting diode elements 2a located at both ends is made stronger than the light emitting intensity of the other light emitting diode elements 2a. Even if the light emitted from the light emitting diode elements 2a located at both ends of 2 is disturbed thickly when passing through the outer periphery of the lens 3a, the light amount applied to the photoconductor P is smaller than that of the other light emitting diode elements 2a. As a result, the surface of the photoconductor P is substantially evenly irradiated, and a latent image with extremely high image quality can be formed on the photoconductor P. It becomes possible.

The present invention is not limited to the above-mentioned embodiments, and various modifications can be made without departing from the scope of the present invention. For example, between the base plate 1 and the lens plate 3 Further, when the light shielding plate 10 is arranged between the adjacent light emitting diode element arrays 2, even if the light emitted from the light emitting diode elements 2a of each light emitting diode element array 2 tries to leak to the adjacent light emitting diode element array 2 side. The leakage is completely blocked by the light shielding plate 10, and as a result, the light emitted from the light emitting diode elements 2a of each light emitting diode element array 2 is irradiated and imaged on the photoconductor P only through the corresponding lens 3a. As a result, bleeding or the like due to unnecessary light irradiation is eliminated on the photoconductor P, and an extremely clear latent image can be formed. Therefore, it is preferable to dispose the light shielding plate 10 between the base plate 1 and the lens plate 3 and between the adjacent light emitting diode element arrays 2.

[0029]

According to the image forming apparatus of the present invention, the electrodes of the image elements located at both ends of each image element array mounted on the base plate are parallel to the arrangement direction of the image elements, and other images are formed. The electrodes of the image elements are led out in the direction perpendicular to the arrangement direction of the image elements, and the emission intensity of the image elements located at both ends is made stronger than the emission intensity of the other image elements. Therefore, each image element of the image element array is individually selected. Light, and irradiate the photoconductor surface with the light through the lens,
When a latent image is formed on the photoconductor, even if the light emitted from the image elements located at both ends of the image element array is thickly disturbed when passing through the outer peripheral portion of the lens, the amount of light irradiated to the photoconductor is equal to that of other image elements. The light irradiation on the surface of the photoconductor becomes uniform, and a latent image with extremely high image quality can be formed on the photoconductor.

[Brief description of drawings]

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

FIG. 2 is a sectional view taken along line XX of FIG.

3 is an enlarged cross-sectional view of a main part of the image forming apparatus shown in FIG.

4 is an enlarged plan view of an image element array of the image forming apparatus shown in FIG.

[Explanation of symbols]

 1 ... Base plate 2 ... Light emitting diode element array 2a ... Light emitting diode element 3 ... Lens plate 3a Lens 4 ...・ Spacer 8 ・ ・ ・ ・ Individual electrode P ・ ・ ・ ・ ・ ・ ・ ・ Photoconductor

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI technical display location H01L 33/00 N

Claims (1)

[Claims] 1. A lens plate in which a plurality of lenses are linearly arranged and supported at predetermined intervals, and a base plate in which a plurality of image element arrays in which a large number of image elements are linearly arranged are linearly mounted. Is an image forming apparatus in which each lens and each image element array are fixed side by side so that each lens and each image element array have a one-to-one correspondence, and each of the image element arrays has electrodes of image elements located at both ends thereof. Is led out in a direction parallel to the arrangement direction of the image elements, and the electrodes of the other image elements are led out in a direction perpendicular to the arrangement direction of the image elements.