JP2001277587A - Optical printer head - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical printer head capable of maintaining linearity of a rod lens array good with simple assembling. SOLUTION: The optical printer head comprises the housing 4 having a strip-like opening on its upper surface and a long-sized frame 6 formed along an outer periphery of the opening and arranged on a board having a plurality of light emitting element array chip loaded in one row state thereon so that the opening is disposed on the chip, and the rod lens array 3 engaged with an inside of the frame 6 of the housing 4. In this case, a plurality of protrusions 1 are provided on an inner surface of the frame 6. A side face of the array 3 is pressed and sandwiched by the protrusions 1. Thus, the array 3 is held in the frame 6.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical printer head used as an exposure means for an electrophotographic printer or the like.

[0002]

2. Description of the Related Art Conventionally, optical printer heads such as LED array heads have been used as exposure means for electrophotographic printers and the like.

As shown in FIG. 3, for example, such a conventional optical printer head has a housing 14 having a band-shaped opening 15 on the upper surface and a substantially rectangular frame 16 formed along the outer periphery thereof. To a plurality of LED array chips 1
2 are mounted on the substrate 11 on which the openings 1 are mounted.
5 is arranged so as to be located directly above the LED array chip 12, and the rod lens array 13 is held in a frame 16 of the housing 14. Array chip 12
A large number of light emitting diode elements provided on the upper surface of the light emitting device are selectively and individually lit based on image data from the outside, and the radiated light is irradiated to an external photosensitive member via the rod lens array 13; By forming a predetermined latent image on the photoconductor, it functions as an optical printer head.

Then, the latent image formed on the photoreceptor becomes a toner image through a developing process, and a predetermined image is formed on the recording paper by transferring and fixing the toner image on the recording paper.

The rod lens array 13 has a structure in which a number of rod-shaped lenses 13a made of glass are arranged in a linear or staggered manner, and these are housed in a frame-shaped case 13b. , The rod lens array 1
3 is inserted into the frame 16 of the housing 14 and positioned. In this state, an instant adhesive 17 such as an epoxy resin is attached to both the side surface of the rod lens array 13 and the frame 16 and is cured. Thus, the rod lens array 13 is fixed at a predetermined position in the frame 16.

[0006]

However, according to the above-described conventional optical printer head, when the rod lens array 13 is mounted on the housing 14, the rod lens array 13 is mounted in the frame 16 using a large jig or the like. It must be positioned at a predetermined position, and the above-mentioned bonding operation must be performed while maintaining this state. Therefore, the workability for mounting the rod lens array 13 is extremely poor, and there is a disadvantage that the productivity of the optical printer head cannot be improved.

According to the conventional optical printer head described above, the rod lens array 13 is fixed with the hard instant adhesive 17 made of epoxy resin or the like.
When thermal stress is applied between the housing 14 and the rod lens array 13 due to a change in ambient temperature or the like, the rod lens array 13 and the like are warped, and the rod lens array 1 is bent.
The linearity of 3 is lost. In this case, the position of the light irradiated on the photoconductor is shifted in the sub-scanning direction, and the focus of the rod lens array 13 is out of focus, thereby causing defects such as image distortion and density unevenness.

[0008]

SUMMARY OF THE INVENTION The present invention has been devised in view of the above-mentioned drawbacks. An optical printer head according to the present invention has a band-shaped opening on the upper surface, and has a rectangular shape along the outer periphery of the opening. A housing in which a frame is formed is disposed on a substrate on which a plurality of light emitting element array chips are mounted in a row, such that the opening is located on the light emitting element array chip, and An optical printer head having a rod lens array inserted inside a frame of a housing, wherein a plurality of projections are provided on an inner surface of the frame, and the projections press and hold a side surface of the rod lens array. It is characterized by the following.

The optical printer head according to the present invention is characterized in that the projection has a curved surface with a radius of curvature of 0.5 mm to 2.0 mm.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to the accompanying drawings. 1 is an exploded perspective view of an optical printer head according to an embodiment of the present invention, FIG. 2 is a cross-sectional view of the optical printer head of FIG. 1, FIG. 3 is a side view of the optical printer head of FIG. 2 is L as a light emitting element array chip
An ED array chip, 3 is a rod lens array, 4 is a housing, 5 is an opening, 6 is a frame, 7 is a protrusion, and 8 is a base plate.

The substrate 1 is formed in a rectangular shape using an electrically insulating material such as a glass cloth base epoxy resin, glass, or ceramic, and has an LED array chip 2, a circuit pattern (not shown), a driver IC, and the like on its upper surface. It functions as a supporting base material for supporting.

When the substrate 1 is made of, for example, a glass cloth base epoxy resin, a glass cloth base formed using glass threads is impregnated with a liquid epoxy resin and cured.
It is manufactured by cutting this into a predetermined rectangular shape.

A plurality of LEs are provided on the upper surface of the substrate 1.
The D array chips 2 are mounted in a line.

Each of the plurality of LED array chips 2 has a plurality of light emitting diode elements 2a linearly arranged at a dot density of, for example, 600 dpi on each upper surface. When power is applied via the circuit pattern, the light emitting diode element 2a emits light at a predetermined luminance.

As such a light emitting diode element 2a, for example, a GaAlAs-based or GaAsP-based light emitting diode element or the like is suitably used. The LED array chip 2 having such a light emitting diode element 2a employs a conventionally known semiconductor manufacturing technique. It is produced by doing.

A long housing 4 is mounted on the substrate 1 on which the plurality of LED array chips 2 are mounted.

The housing 4 has a band-shaped opening 5 extending along the longitudinal direction of the housing 4 at an upper portion thereof, and a thickness of 1.0 mm or more integrally formed along the outer periphery of the opening 5.
And a rectangular frame 6 of about 2.0 mm. The opening 5 is disposed at a predetermined position on the substrate 1 such that the opening 5 is located directly above the LED array chip 2.

The housing 4 holds the rod lens array 3 in a frame 6 provided on the upper part thereof and seals a space formed between the rod lens array 3 and the LED array chip 2. The material is a resin such as polycarbonate or liquid crystal polymer,
Alternatively, a metal such as aluminum or steel is used. For example, when the housing 4 is formed of polycarbonate, the housing 4 is manufactured to have a predetermined shape by adopting a conventionally known injection molding.

On the other hand, the rod lens array 3 held in the frame 6 of the housing 4 is composed of a large number of bar-shaped lenses 3a arranged linearly or a large number of bar-shaped lenses 3a arranged in a staggered manner. This is an erecting equal-magnification lens disposed and accommodated in the case 3b.

Since the rod lens array 3 is disposed directly above the LED array chip 2 along the arrangement of the LED array chips 2, when the light emitting diode elements 2a of the LED array chip 2 emit light, these lights are emitted. Irradiation and image formation are performed on an external photoconductor at the same magnification.

The rod lens array 3 is held in the frame 6 by a plurality of protrusions 7 provided on the inner surface of the frame 6.

Each of the plurality of protrusions 7 has a width of, for example, 0.5 mm to 2.0 mm, and projects from the inner surface of the frame 6 by, for example, 0.1 mm to 0.5 mm toward the rod lens array 3. Between 25.0mm and 50.0m
The protrusions 7 are arranged in the main scanning direction with an interval of m, for example, when an A4 size optical printer head is configured, the protrusions 7 are provided at nine locations on both sides of the rod lens array 3 with the rod lens array 3 at the center. It is provided integrally with the frame body 6 at symmetrical positions.

The projections 7 hold the rod lens array 3 in the frame 6 by pressing and nipping the side surfaces of the rod lens array 3 at the respective tip portions. Array 3 to housing 4
When the rod lens array 3 is once inserted into the frame 6, when the rod lens array 3 is inserted into the frame 6, the rod lens array 3 is always well held in the frame 6 by the pressing force of the projection 7, and the position of the rod lens array 3 is changed. The rod lens array 3 can be attached by a simple operation of moving up and down and making fine adjustments. Therefore, it is not necessary to separately hold the rod lens array 3 using a large-sized jig or the like during the mounting operation of the rod lens array 3, and the workability for mounting the rod lens array 3 is improved, and the optical printer head is mounted. It is possible to assemble efficiently.

Further, in this case, the rod lens array 3 is held in the frame 6 of the housing 4 only by the pressing force from the projection 7 without using a hard instant adhesive or the like. Therefore, even if the housing 4 and the rod lens array 3 undergo thermal expansion in accordance with the respective linear expansion coefficients due to a change in ambient temperature or the like, the side surface of the rod lens array 3 and the distal end of the projection 7 are still in contact. Just by sliding in the longitudinal direction of the rod lens array 3, the rod lens array 3 does not warp due to a difference in linear expansion coefficient from the housing 4. Therefore, the linearity of the rod lens array 3 is always kept good, and the light of the light emitting diode element 2a is irradiated and imaged on the external photoreceptor with accurate and uniform intensity through the rod lens array 3. A clear image without distortion or density unevenness can be formed.

The plurality of protrusions 7 have a radius of curvature of 0.5 mm or less in contact with the side surface of the rod lens array 3.
It is processed to form a 2.0 mm curved surface. Therefore, the sliding between the rod lens array 3 and the projection 7 described above becomes extremely smooth, and therefore, the workability in positioning the rod lens array 3 in the frame 6 is further improved, and the rod lens array 3 Warpage is more reliably prevented.

Further, the housing 4 has a bending elasticity of 20 × 1.
If it is formed of resin or the like of 0 ³ kg / cm ² or more,
The frame 6 provided with the projections 7 is provided with a spring property suitable for holding the rod lens array 3 so that the rod lens array 3 can be retained even when an external force such as vibration is applied to the optical printer head. There is also an advantage that it can be reliably held in the frame body 6 by the pressing. Therefore, it is preferable that the housing 4 is formed of a resin having a bending elasticity of 20 × 10 ³ kg / cm ² or more.

Further, if the projection 7 is formed in a vertically long shape parallel to the optical axis direction of the rod lens array 3, the rod lens array 3 is oriented in the direction of the projection 7 when the rod lens array 3 is mounted on the housing 4. Since the rod lens array 3 is smoothly inserted into the frame body 6 along with the rod lens array 3, the rod lens array 3 can be easily moved in the vertical direction, and there is an advantage that the workability for mounting the rod lens array 3 is further improved. Therefore, it is preferable that the protrusion 7 is provided in a vertically long shape along the optical axis of the rod lens array 3.

A base plate 8 is arranged on the lower surface side of the substrate 1 described above, and the substrate 1 is held between the base plate 8 and the housing 4.

The base plate 8 is formed in a U-shape by, for example, a metal such as SUS, and the base plate 8 is fixed to the housing 4 side by using a leaf spring-shaped fixing metal 9 formed in a U-shape. , The substrate 1 is stably held between the housing 4 and the base plate 9.

Thus, the above-described optical printer head has an L
The light emitting diode elements 2a of the ED array chip 2 are selectively and individually illuminated based on image data, and the emitted light is irradiated and imaged on an external photoreceptor via the rod lens array 3 to form an image on the photoreceptor. By forming a predetermined latent image, it functions as an optical printer head.

The latent image formed on the photoreceptor then undergoes a development process to become a toner image, and a predetermined image is formed on the recording paper by transferring and fixing the toner image on the recording paper.

Note that 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-described embodiment, the projections 7 on the inner surface of the frame are provided on the both sides of the rod lens array 3 at a total of 18 locations, that is, at a total of 18 locations.
Up to 17 or 19 or more, such projections 7
May be different on both sides of the rod lens array 3.

In order to close the gap between the rod lens array 3 and the frame 6 in the above embodiment,
This gap is made of a hardness made of silicone resin (JIS).
A) The sealing may be performed using a soft resin of 30 to 60.

In the above embodiment, the LED array head has been described as an example. However, the present invention is applicable to other optical printer heads such as an EL head, a plasma dot head, a liquid crystal shutter head, a fluorescent head, and a PLZT. It is possible.

[0036]

According to the optical printer head of the present invention, a plurality of projections are provided on the inner surface of the frame into which the rod lens array is inserted, and these projections press and hold the side surface of the rod lens array. Since the rod lens array is held, once the rod lens array is inserted into the frame at the time of assembling the optical printer head, the rod lens array is always well held in the frame by the pressing force of the projection. The rod lens array can be mounted by a simple operation of finely adjusting the position of the rod lens array by moving it up and down. Therefore, it is not necessary to separately hold the rod lens array using a large-scale jig or the like during the mounting operation of the rod lens array, and the workability for mounting the rod lens array is improved, and the optical printer head is efficiently assembled. It becomes possible.

According to the optical printer head of the present invention,
Since the rod lens array is held by the pressing force from the protrusion in the housing frame, the housing and the rod lens array are moved in accordance with the respective linear expansion coefficients with a change in ambient temperature or the like. Even if thermal expansion occurs, only the side surface of the rod lens array and the tip of the protrusion slide in the longitudinal direction of the rod lens array. No warping occurs. Therefore, the linearity of the rod lens array is always kept good, and by irradiating the light of the light emitting element to an external photoreceptor with accurate and uniform intensity through the rod lens array with uniform intensity, distortion and density unevenness are obtained. And a clear image free of defects can be formed.

Further, according to the optical printer head of the present invention,
By forming the protrusions into a curved surface having a radius of curvature of 0.5 mm to 2.0 mm, the sliding between the rod lens array and the protrusions becomes smooth. Therefore, the workability in positioning the rod lens array in the frame is improved, and the warpage of the rod lens array is more reliably prevented.

[Brief description of the drawings]

FIG. 1 is a plan view of an optical printer head according to one embodiment of the present invention.

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

FIG. 3 is a sectional view of a conventional optical printer head.

[Explanation of symbols]

1 ... substrate, 2 ... LED array chip (light emitting element array chip), 3 ... rod lens array, 4 ...
・ Housing, 5 ・ ・ ・ Opening, 6 ・ ・ ・ Frame, 7 ・ ・ ・
Protrusion

Claims (2)

[Claims] 1. A substrate on which a plurality of light emitting element array chips are mounted in a row, the housing having a band-shaped opening on the upper surface and a rectangular frame formed along the outer periphery of the opening. An optical printer head, wherein the opening is disposed above the light emitting element array chip, and a rod lens array is inserted inside a frame of the housing, wherein an inner surface of the frame is provided. An optical printer head, wherein a plurality of projections are provided on each of the projections, and the projections press and hold the side surfaces of the rod lens array. 2. The projection has a radius of curvature of 0.5 mm to 2.0 m.
2. The optical printer head according to claim 1, wherein the optical printer head has a curved surface of m.