JP2000158705A - Production of optical printer head - Google Patents

Abstract

PROBLEM TO BE SOLVED: To largely improve the productivity of an optical printer head. SOLUTION: An optical printer head comprising a plurality of light emitting element array chips and a plurality of lenses 4 disposed corresponding to each other one by one, wherein the plurality of the lenses are produced by a step of disposing a frame member 3 having a plurality of hole parts 3a on the upper surface of a transparent substrate 1, a step of introducing a glass paste 4' or a liquid transparent resin precursor in each hole part 3a of the frame member 3 so as to have a substantially spherical surface according to its own surface tension, and a step of forming a plurality of lenses 4 integrally with the transparent substrate 1 according to curing of the glass paste 4' or the precursor filled in the hole parts 3a.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing an optical printer head used as a light source for an electrophotographic printer or the like.

[0002]

2. Description of the Related Art Conventionally, an optical printer head such as an LED printer head has been used as a light source for an electrophotographic printer or the like.

In such an optical printer head, for example, a plurality of light emitting element array chips supported on a base plate and a plurality of lenses supported on a lens plate are paired with the array chip and the lens. The light-emitting elements of the light-emitting element array chip are selectively emitted and driven individually in accordance with external printing data, and the emitted light is emitted. The device functions as an optical printer head by irradiating and forming an image on an external photoconductor via the lens and forming a predetermined latent image on the photoconductor. A predetermined light transmission hole is formed in the lens plate, and light from the light emitting element array chip is introduced into the corresponding lens through the transmission hole.

The lens is made of glass or a transparent resin. For example, when the lens is made of a transparent resin such as polymethyl methacrylate or polycarbonate, the lens is manufactured individually by well-known injection molding or the like. It is supported on the lens plate by individually positioning and fixing a predetermined number and a predetermined position of the lens plate.

[0005] At this time, if the positional relationship between the lens and the light emitting element array chip deviates, the latent image formed on the photoreceptor will be blurred, white stripes, black stripes, etc.
In order to obtain an accurate latent image, it is necessary to position the lens with extremely high precision (within ± 5 μm).

[0006]

However, in the above-mentioned conventional optical printer head, a plurality of lenses are individually positioned and fixed on a lens plate, and the positioning of each lens is extremely high. Since positional accuracy is required, it takes a long time to position the lens, and as a result, there is a disadvantage that the productivity of the optical printer head is greatly reduced.

In a conventional optical printer head,
Since the plurality of light emitting element array chips and the plurality of lenses are supported by separate plates, even if the initial lens position is accurate, the photoconductor and paper supply mechanism will be required for subsequent use. The lens may be displaced with respect to the light emitting element array chip due to vibration from other devices such as a developing device, a heat fixing device, and a difference in linear expansion coefficient between the lens plate and the base plate. In this case, the latent image formed on the photoreceptor suffers from defects such as blurring, white streaks, and black streaks.

[0008]

SUMMARY OF THE INVENTION The present invention has been devised in view of the above-mentioned disadvantages, and a method of manufacturing an optical printer head according to the present invention comprises a plurality of light emitting element array chips and a plurality of lenses. 1. An optical printer head arranged in correspondence with No. 1, wherein the plurality of lenses are formed by the following steps:

Step: A step of arranging a frame having a plurality of holes on the upper surface of a transparent substrate Step: A precursor of a glass paste or a liquid-state transparent resin is filled in each hole of the frame. A step of causing the surface to become substantially spherical by surface tension Step: a step of forming a plurality of lenses integrally with the transparent substrate by curing the glass paste or the precursor filled in the holes. In the method of manufacturing an optical printer head according to the present invention, the plurality of light emitting element array chips are mounted on a lower surface of the transparent substrate.

Further, in the method of manufacturing an optical printer head according to the present invention, the lens is formed of a transparent material of the same quality as the transparent substrate.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 is a sectional view of an optical printer head manufactured by the method of the present invention, FIG. 2 is a top view of a transparent substrate used in the optical printer head of FIG. 1, 1 is a transparent substrate, 2 is a light emitting element array chip, 3 is a frame, 3a is a hole, and 4 is a lens.

The transparent substrate 1 is made of a transparent insulating material such as borosilicate glass, quartz, sapphire, crystallized glass or the like, and has a plurality of light emitting element array chips 2 arranged and mounted linearly on the lower surface thereof. And a power supply circuit pattern (not shown) for supplying power from an external power supply to the array chip 2, and a plurality of lenses 4 and a frame corresponding to the light emitting element array chip 2 on a one-to-one basis. Each of the bodies 3 is attached.

The transparent substrate 1 functions as a supporting base material for supporting the light emitting element array chip 2, the frame 3, the lens 4 and the like on the upper and lower surfaces thereof. For example, when the transparent substrate 1 is made of borosilicate glass, It is manufactured by forming a plate having a predetermined thickness by a conventionally known floating method or the like, and cutting and processing the plate into a predetermined shape.

The reason why the substrate 1 is made of a transparent material is that light from the light emitting element array chip 2 attached and mounted on the lower surface is transmitted to the upper surface of the substrate 1 on which the lens 4 is disposed. It is to make it.

A plurality of light emitting element array chips 2 arranged and mounted on the lower surface of the transparent substrate 1 have a large number of light emitting elements arranged linearly on each upper surface.
When power from an external power supply is applied to these light-emitting elements based on external printing data, the light-emitting elements are selectively and individually made to emit light. The light emitted from these light emitting elements is applied to the surface of the photoconductor P via a lens 4 described later, and forms a predetermined latent image on the photoconductor P.

As such a light emitting element, for example, GaAs
An sP-based or GaP-based light-emitting diode is used. For example, in the case of a GaAsP-based light-emitting diode,
The substrate of aAs is heated to a high temperature in a furnace and the AsH
₃ (arsine), PH ₃ (phosphine), and a gas containing an appropriate amount of Ga (gallium) are brought into contact with each other to grow an n-type semiconductor GaAsP (gallium-arsenic-phosphorus) single crystal on the substrate surface. A windowed film of Si ₃ N ₄ (silicon nitride) is deposited on the crystal surface, and Zn
(Zinc) gas is exposed, Zn is diffused into a part of the n-type semiconductor GaAsP single crystal to form a p-type semiconductor, and pn
It is formed by having a bond.

For example, in the case of forming an A4 size, 300 dpi optical printer head, 40 508 dpi light emitting diode array chips each having 64 light emitting diodes as one unit are provided on the lower surface of the transparent substrate 1 and the light emitting surface thereof is transparent. The chips are arranged and mounted linearly so as to face the substrate 1 and at a predetermined interval between the individual chips. The mounting of the light emitting diode array chip on the transparent substrate 1 is performed by, for example, conventionally known face-down bonding.

On the other hand, the frame 3 on the upper surface of the transparent substrate has a plurality of holes 3a arranged linearly, and a lens 4 is individually disposed in each of the holes 3a. .

The frame 3 is made of Ag (silver), Au (gold), C
u (copper), Ni (nickel), etc.
The third hole 3a is formed in a substantially circular shape on each light emitting element array 2, and the inner peripheral surface thereof supports the outer peripheral portion of the lens 4.

The lens 4 is made of, for example, a transparent material of the same quality as that of the transparent substrate 1, for example, borosilicate glass, and corresponds to the light emitting element array 2 described above in one-to-one correspondence.
More specifically, after being arranged so that the optical axis of each lens 4 is located at the center of the corresponding light emitting element array 2, the transparent substrate
1 is baked on top.

The lens 4 functions to magnify the light of the light emitting elements of the light emitting element array 2 at a predetermined magnification and irradiate the light to the external photoconductor P in a linear manner, that is, the light from all the light emitting element arrays 2. Is illuminated and imaged in a line on the surface of the photoconductor P.

For example, a 508 dpi light emitting element array 2
When an A4 size optical printer head is constituted by using 40 lenses, a lens 4 having a magnification of 1.692 times is provided with a light emitting element array.
2 is disposed 8.8 mm above the light emitting surface. still,
In this case, the distance between adjacent light emitting element arrays 2 is 5.4.
It is set to 14 mm.

In this case, the lens 4 is provided on the transparent substrate 1.
Since the linear expansion coefficient of the lens 4 is substantially equal to the linear expansion coefficient of the transparent substrate 1, the optical printer head was used as the light source of the electrophotographic printer. In this case, even when heat is applied to both the lens 4 and the transparent substrate 1, the lens 4 and the transparent substrate 1 thermally expand by substantially the same amount, and no positional displacement or large thermal stress occurs between the two. Therefore, the light from the light emitting element array 2 is accurately and clearly irradiated and imaged on the photoconductor P via the corresponding lens 4.

In the optical printer head described above, predetermined power is applied to each light emitting element of the light emitting element array 2 mounted on the lower surface of the transparent substrate 1 based on external printing data, and the light emitting elements are individually selectively selected. In addition, the emitted light is radiated and imaged on an external photoconductor P via a lens 4 to form a predetermined latent image on the photoconductor P, thereby functioning as an optical printer head.

Next, a method of forming the lens 4 used in the above-described optical printer head will be described with reference to FIGS.

[Step] First, as shown in FIG. 3A, a transparent substrate 1 having a predetermined power supply circuit pattern (not shown) attached on the lower surface thereof is prepared, and FIG. b)
A frame 3 having a plurality of holes 3a is attached and arranged as shown in FIG.

The frame 3 is made of Ag (silver) or slightly Au.
A predetermined metal paste containing a metal powder such as (gold), Cu (copper), and Ni (nickel) is printed and applied in a predetermined pattern by a conventionally known screen printing or the like.
1 μm by baking at a temperature of 0 ° C. to 600 ° C.
It is deposited and formed to a thickness of 10 to 10 μm. The hole 3a
Is to be set according to the length of the light emitting element array 2. For example, the length of the light emitting element array 2 is 4 m.
In the case of m, for example, it is formed so as to form a substantially circular shape having a diameter of 2 mm to 4 mm.

[Step] Next, as shown in FIG. 3 (c), each hole 3a of the frame 3 is filled with a predetermined amount of glass paste 4 '.

The glass paste 4 'is prepared by adding and mixing an appropriate organic solvent and a solvent to, for example, borosilicate glass powder, and the glass paste 4' is introduced into the hole 3a using a dispenser D or the like. Is filled by At this time, the spread of the glass paste 4 'filled in each hole 3a is equally regulated by the inner periphery of the hole 3a, and the surface of the glass paste 4' is curved, more specifically, by its own surface tension. Specifically, it has a substantially spherical shape with a radius of curvature of 2 mm to 10 mm.

[Step] And finally, as shown in FIG. 3D, the glass paste 4 'filled in each hole 3a is cured to form a plurality of lenses 4.

The hardening of the glass paste 4 'is performed by applying heat. For example, the softening temperature of the frame 3 is 600 ° C.
, A lower temperature (500 ° C. to 550 ° C.)
The glass paste 4 ′ is baked at a temperature of 2 ° C., whereby a plurality of lenses 4 are firmly and integrally attached and formed on the upper surface of the transparent substrate 1.

Further, a plurality of light emitting element array chips 2 are mounted on the lower surface of the transparent substrate 1 by a conventionally known face-down bonding or the like, whereby an optical printer head as a product is completed.

A plurality of lenses are manufactured by the above manufacturing method.
When forming the glass paste 4, the spread of the glass paste 4 ′ filled in the hole 3 a of the frame 3 is substantially equally regulated by the inner circumference of each hole 3 a, and the glass paste 4 ′ filled in the hole 3 a is filled. The diameter and surface shape of 4 ′ are substantially equal. Therefore, the shapes and sizes of the plurality of lenses 4 obtained by curing these glass pastes 4 ′ are all substantially equal, and each lens 4 is accurately positioned by the inner circumference of the hole of the frame 3. Also, the positioning of the lens 4 becomes extremely high. That is, according to the manufacturing method of the present invention, the alignment of the lens 4 can be performed almost at the same time as the formation of the lens 4, whereby the productivity of the optical printer head can be greatly improved.

According to the manufacturing method of this embodiment, the plurality of lenses 4 and the plurality of light emitting element array chips 2 are formed on a single substrate.
1, even if vibrations from other devices such as a photoreceptor, a paper supply mechanism, a developing device, and a heat fixing device are applied during use, the position between the lens 4 and the light emitting element array chip 2 is increased. There is no deviation, and a good latent image with few blurs, white streaks, black streaks, etc. can be formed on the photoconductor P.

Further, according to the manufacturing method of the present embodiment, by forming the lens 4 with a transparent material of the same quality as the transparent substrate 1,
The two linear expansion coefficients are not made substantially equal to each other, whereby the positional deviation between the lens 4 and the light emitting element array chip 2 due to the difference in the linear expansion coefficients can be effectively prevented.
In this case, an extremely good latent image with almost no blur, white streak, black streak, etc. is formed on the photoconductor P.

The present invention is not limited to the above-described embodiment, and various changes and improvements can be made without departing from the gist of the present invention.

For example, in the above embodiment, the transparent substrate 1 and the lens
Although 4 is formed of an inorganic material such as borosilicate glass, the transparent substrate 1 and the lens 4 may be formed of a transparent resin material such as an acrylic resin or a polycarbonate resin instead. In this case, in order to form the lens 4, a precursor of a liquid transparent resin is used in place of the glass paste 4 ′, and the precursor is thermally cured (polymerized) at a temperature of, for example, 150 ° C. to 250 ° C. Alternatively, photo-curing is performed by irradiating ultraviolet rays of a predetermined wavelength. Also in this case,
In the case where one of the transparent substrate 1 and the lens 4 is formed of a transparent resin, the other is preferably formed of a transparent resin from the viewpoint of matching the linear expansion coefficients.

In the above embodiment, the plurality of light emitting element array chips 2 and the plurality of lenses 4 are supported by one transparent substrate 1, but instead of this, the plurality of light emitting element array chips 2 and The plurality of lenses 4 may be supported by separate transparent substrates. 4 and 5 show such modifications.

For example, in the embodiment shown in FIG. 4, a plurality of lenses 4 are formed on a first transparent substrate 1a and a plurality of light emitting element array chips 2 are formed.
Is supported by the second transparent substrate 1b, and further the second transparent substrate 1b
A plurality of microlenses 5 are attached to the upper surface of the device to extract light more efficiently. When manufacturing such an optical printer head, the micro lens 5 is also formed by the same manufacturing method as the lens 4 described above.

In the embodiment shown in FIG. 5, two transparent substrates 1c, 1
Using d, multiple lenses 4 and light emitting element array chip 2
4 is supported on separate substrates, but in this embodiment, lenses 4a and 4b are attached to the upper and lower surfaces of the first transparent substrate 1c so as to face each other. In this case, since the light emitted from the light emitting element is satisfactorily captured by the lens 4b and the light can be satisfactorily condensed by the lens 4a, there is also an advantage that sharper light (beam) can be obtained.

Further, in the above-described embodiment, printing and baking of a metal paste are employed for disposing the frame 3 on the transparent substrate 1. Instead, the frame is manufactured in advance, and the frame May be arranged at a predetermined position by fixing it to the upper surface of the transparent substrate with an adhesive or the like. In this case, as the material of the frame, it is preferable to use a glass paste used for forming a lens or a material having a poor wettability with a precursor of a liquid transparent resin.

Further, in the above-described embodiment, the hole 3a of the frame 3 is made circular, but is not limited to this shape.
For example, the hole 3a may have an elliptical shape or a substantially square shape.

[0043]

According to the present invention, when a plurality of lenses are formed, the spread of the glass paste or the like filled in the holes of the frame is substantially equally regulated by the inner periphery of each hole. The diameter and the surface shape of the glass paste or the like filled in the part are substantially equal. Therefore, the shape of a plurality of lenses obtained by curing these glass pastes,
Since the sizes are all substantially equal, and since each lens is accurately positioned by the inner periphery of the hole of the frame, the positioning of the lens is extremely accurate. That is, the alignment of the lens can be performed almost simultaneously with the formation of the lens, thereby greatly improving the productivity of the optical printer head.

According to the present invention, a plurality of light emitting element array chips and a plurality of lenses are supported by a common transparent substrate, so that when an optical printer head is used, vibrations from other devices and the like are caused. Is applied, no positional deviation occurs between the lens and the light emitting element array chip, and a good latent image with few blurs, white stripes, black stripes, etc. can be formed on the photoreceptor.

Further, according to the present invention, since the lens is formed of a transparent material of the same quality as the transparent substrate, the linear expansion coefficients of the two are not made substantially equal, whereby the lens resulting from the difference in the linear expansion coefficient is obtained. -The displacement between the light emitting element array chips can be effectively prevented. As a result, an extremely good latent image having almost no blur, white streak, black streak, or the like is formed on the photosensitive member.

[Brief description of the drawings]

FIG. 1 is a sectional view of an optical printer head manufactured by a manufacturing method of the present invention.

FIG. 2 is a top view of a transparent substrate used in the optical printer head of FIG.

3 (a) to 3 (d) are cross-sectional views for each step for explaining a manufacturing method of the present invention.

FIG. 4 is a sectional view of an optical printer head manufactured according to a modification of the present invention.

FIG. 5 is a sectional view of an optical printer head manufactured according to a modification of the present invention.

[Explanation of symbols]

1 ... transparent substrate, 2 ... light emitting element array chip, 3
・ ・ ・ Frame, 3a ・ ・ ・ Hole, 4 ・ ・ ・ Lens, 4 '・ ・ ・
Glass paste

Claims (3)

[Claims] 1. An optical printer head having a plurality of light emitting element array chips and a plurality of lenses arranged in one-to-one correspondence, wherein the plurality of lenses are formed by the following steps: A method for manufacturing an optical printer head, comprising: Step: A step of disposing a frame having a plurality of holes on the upper surface of a transparent substrate Step: A precursor of a glass paste or a liquid-state transparent resin is applied to each hole of the frame by its own surface tension. Step of making the surface enter a substantially spherical shape Step: Step of forming a plurality of lenses integrally with the transparent substrate by curing the glass paste or the precursor filled in the holes 2. The method according to claim 1, wherein the plurality of light emitting element array chips are mounted on a lower surface of the transparent substrate.
3. The method for manufacturing an optical printer head according to claim 1. 3. The method according to claim 1, wherein the lens is formed of a transparent material of the same quality as the transparent substrate.