JP2002326388A - Optical printer head - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical printer head in which the light from a light emitting element array chip can be focused accurately on the surface of a photosensitive body by correcting deformation of a housing for fixing a lens array thereby sustaining high linearity of the lens array. SOLUTION: The optical printer head comprises a circuit board 1 mounting a plurality of light emitting element array chips 2 arranged in a line, and a resin housing 4 for holding a lens array 3 above the light emitting element array chips 2 such that a reference plane 4b, provided at a lower part thereof, abuts against the upper surface of the circuit board 1. A plurality of positioning pins 5 are arranged along the line of the light emitting element array chips 2 on any one of the reference plane 4b of the housing 4 or the upper surface of the circuit board 1 and a plurality of reference holes 6, each having an opening larger than the forward end part of the positioning pin 5, are made in the other of the reference plane 4b of the housing 4 or the upper surface of the circuit board 1. Under a state where the housing 4 is deformed resiliently, the positioning pins 5 are secured at a specified position in the reference holes 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 optical writing 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 optical writing means in electrophotographic printers and the like.

As such a conventional optical printer head, for example, as shown in FIG. 4, on a circuit board 11 on which a plurality of light emitting element array chips 12 are mounted in a line,
The lens array 1 above the light emitting element array chip 12
A structure in which a plurality of light emitting elements 12a provided on an upper surface of the light emitting element array chip 12 are individually accommodated in correspondence with image data from the outside is known. By selectively emitting light and irradiating and forming an image on an external photosensitive member via the lens array 14 to form a predetermined latent image on the photosensitive member, the device 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 recorded on the recording paper by transferring and fixing the toner image on the recording paper. Becomes

The housing 13 of the optical printer head is made of a resin such as polycarbonate or liquid crystal polymer. It had been.

[0006]

However, in the above-described conventional optical printer head, when the housing 13 is formed by injection molding or the like, the outer shape of the housing 13 is greatly curved due to contraction stress applied during molding. Often, it deforms into a constricted shape at the center.
The lens array 1 is located at a predetermined position of the housing 13.
When fixing the lens array 4 using an adhesive, the shape of the opening for mounting the lens array provided on the upper part of the housing 13 does not match the shape of the lens array 14, so that it is difficult to mount the lens array 14. When the lens array 14 is bonded to the housing 13, the outer shape of the lens array 14 is pulled by the housing 13 and deformed, so that the linearity of the lens array 14 is significantly reduced.
A disadvantage that a part of the lens array 14 is displaced from above the light emitting element array chip 12 so that it is impossible to accurately form light from the light emitting element array chip 12 on the surface of the photoreceptor via the lens array 14. Had.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned drawbacks, and has as its object to correct the deformation of a housing in which a lens array is mounted so as to maintain the linearity of the lens array at a high level. An object of the present invention is to provide an optical printer head capable of accurately forming light from an array chip on a surface of a photoconductor.

[0008]

An optical printer head according to the present invention holds a lens array above a light emitting element array chip on a circuit board on which a plurality of light emitting element array chips are mounted in a line. In an optical printer head in which a resin housing is disposed such that a reference surface provided at a lower portion thereof is in contact with an upper surface of the circuit board, the optical printer head may be provided on one of the reference surface of the housing and the upper surface of the circuit board A plurality of positioning pins arranged along the row of the light emitting element array chip, a plurality of reference holes having an opening larger than the tip of the positioning pin are provided on the other side, and the housing is elastically deformed. The positioning pin is fixed at a predetermined position in a reference hole.

In the optical printer head according to the present invention, the resin forming the housing has a flexural modulus of 1.0 × 10 ^4.
kgf / cm ^{2 to} 20 × 10 ⁴ kgf / cm ² .

Further, in the optical printer head according to the present invention, the positioning pin is formed in a tapered shape, and the reference hole is formed in an inverted taper shape in which the positioning pin can be fitted.

Still further, in the optical printer head according to the present invention, the positioning pins are arranged on both sides of the lens array one by one, and an arrangement pitch of the positioning pins forming one row and a positioning pitch forming the other row. The arrangement pitch of the pins is set according to the distance from the lens array.

Still further, in the optical printer head according to the present invention, the circuit board and the housing are integrally held by a leaf spring-shaped clip for pressing the circuit board toward the lens array. is there.

According to the optical printer head of the present invention, a resin housing for holding a lens array above the light emitting element array chips on a circuit board on which a plurality of light emitting element array chips are mounted in a line. Are arranged such that the reference surface provided thereunder is brought into contact with the upper surface of the circuit board, and the reference surface of the housing and the upper surface of the circuit board are arranged along the rows of the light emitting element array chips. A plurality of positioning pins to be arrayed, and a plurality of reference holes each having an opening larger than a tip end of the positioning pin are provided on the other side, and the positioning pins are positioned within the reference hole in a state where the housing is elastically deformed. By fixing to the position, deformation such as curvature and constriction generated during molding of the housing is corrected, and the linearity of the lens array attached to the housing is corrected. It will allow to form high.
Therefore, when the optical printer head is used, it is possible to form a good latent image corresponding to image data by accurately forming light from the light emitting element array chip on the surface of the photoconductor.

According to the optical printer head of the present invention,
If the lens array is inserted into the opening of the housing that has been corrected to a desired shape, the labor required for mounting the lens array is significantly reduced, and there is an advantage that the productivity of the optical printer head is improved.

Further, according to the optical printer head of the present invention,
By arranging the positioning pins in a row on both sides of the lens array and setting the arrangement pitch of these positioning pins in accordance with the distance from the lens array, the positioning pins and the reference holes can reduce the shrinkage stress applied to the housing. Since the lenses are arranged on both sides of the lens array in a well-balanced manner according to the size, the above-described effects can be obtained with the minimum number of positioning pins and reference holes.

Further, according to the optical printer head of the present invention, the circuit board and the housing described above are integrally held by a leaf spring-shaped clip for pressing the circuit board toward the lens array, so that the housing can be referred to as a reference. The surface can be pressed against the upper surface of the circuit board with a simple structure, and the structure of the optical printer head can be effectively prevented from becoming complicated.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to the accompanying drawings. FIG. 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, wherein 1 is a circuit board, 2 is a light emitting element array chip, and 3 is a lens array. 4 is a housing, 5 is a positioning pin, and 6 is a reference hole.

The circuit board 1 has a structure in which a light emitting element array chip 2 and circuit wiring (not shown) are attached to an upper surface of a base made of an electrically insulating material such as glass cloth epoxy resin, glass, or ceramic. ing.

When the base of the circuit board 1 is made of a glass cloth epoxy resin, a glass cloth base material formed by using glass thread is impregnated with a liquid epoxy resin and hardened, and this is processed into a rectangular shape. Thus, a base is formed, and silver (Ag) or copper (Cu) is formed on the upper surface of the obtained base.
It is manufactured by applying and forming a large number of circuit wirings in a predetermined pattern using a conventionally known screen printing or the like of a conductive material mainly composed of, for example.

The plurality of light emitting element array chips 2 mounted on the upper surface of the circuit board 1 have a large number of light emitting elements 2a and electrodes (shown in the drawing) arranged linearly at a density of, for example, 600 dpi on each upper surface. A plurality of light emitting element array chips 2 are mounted on the upper surface of the circuit board 1 in a row so that the light emitting elements 2a are arranged in a straight line in the main scanning direction.

Light emitting element 2 of the light emitting element array chip 2
As a, for example, a GaAlAs-based or GaAsP-based light-emitting diode (LED) is preferably used. When such a light-emitting diode is used as the light-emitting element 2a, power supply power is supplied to the light-emitting element 2a via circuit wiring on the upper surface of the circuit board. Is supplied, electrons and holes are recombined in the vicinity of the pn junction provided in the light emitting element 2a, and the energy generated thereby is converted into light, so that the light emitting element 2a
Emit light at a predetermined luminance.

When the light emitting element 2a is constituted by a GaAlAs-based light emitting diode, a conventionally known semiconductor manufacturing technique, specifically, MOCVD (Metal Organic
Chemical Vapor Deposition)
The light emitting element array chip 2 is manufactured by epitaxially growing a compound semiconductor containing As as a main component on the upper surface of a base made of single crystal silicon or the like, and the obtained light emitting element array chip 2 is mounted at a predetermined position on the upper surface of the circuit board. After that, it is bonded to the circuit wiring on the circuit board 1 by a conventionally known wire bonding method or the like.

On the circuit board 1, a housing 4 for holding the lens array 3 above the light emitting element array chip 2 is mounted.

The lens array 3 is an erecting equal-magnification lens in which a large number of fiber-shaped lenses are linearly or staggeredly arranged in the main scanning direction, and is disposed in a frame 4 a provided on an upper portion of the housing 4. After being inserted, it is fixed to the housing 4 by an adhesive such as an epoxy resin, and when the light emitting element 2a of the light emitting element array chip 2 emits light, these lights are irradiated and coupled to an external photoreceptor at the same magnification. Image.

The housing 4 for holding the lens array 3 has a rectangular frame 4a in which the lens array 3 is inserted, and a lower portion in contact with the upper surface of the circuit board 1 on both sides of the lens array 3. And a pair of reference surfaces 4b. An opening is provided inside the frame 4a for allowing light from the light emitting element array chip 2 to enter the lens array 3.

The housing 4 has a part thereof, specifically, a reference surface 4b brought into contact with the upper surface of the circuit board 1 so that
While maintaining a predetermined distance between the lens array 3 and the light emitting element array chip 2 held at the upper portion, a closed space is formed between the two.

Such a housing 4 is made of a resin such as polycarbonate or liquid crystal polymer which is easily elastically deformed, and more specifically, has a flexural modulus of 1.0 × 10 ⁴ kgf / cm ² to 2 × 10 ⁴ kgf / cm 2.
The housing 4 is formed by molding a resin of 0 × 10 ⁴ kgf / cm ² into a predetermined shape by adopting a conventionally known injection molding or the like. Because the outer shape is greatly curved or deformed into a constricted shape at the center due to the outer shape, the outer shape of the housing 4 is elastically deformed to a desired shape using the positioning pins 5 and the reference holes 6 described later. Has been corrected.

That is, on the reference surface 4b of the housing 4, a plurality of positioning pins 5 arranged along both sides of the row of the light emitting element array chips 2 project toward the circuit board 1 (downward). As described above, on the upper surface of the circuit board 1 described above, a plurality of reference holes 6 having an opening larger than the tip of the positioning pin 5 are provided at positions corresponding to the positioning pin 5. When the positioning pin 5 is fixed at a predetermined position in the corresponding reference hole 6, the outer shape of the housing 4 is elastically deformed into a desired shape, and the curvature and constriction generated during the molding of the housing 4 are corrected extremely well.

Therefore, the linearity of the lens array 3 attached to the housing 4 is maintained at a high level, and when the optical printer head is used, the light from the light emitting element array chip 2 is accurately applied to the surface of the photosensitive member. By forming an image, a good latent image corresponding to the image data can be formed.

In this case, when the lens array 3 is attached to the housing 4, the workability is good because the lens array 3 may be inserted into the opening of the housing 4 corrected to a desired shape. However, the labor required for the mounting operation can be greatly reduced, and the productivity of the optical printer head can be improved.

Each of the positioning pins 5 is formed to have a tapered shape, and is made of a material such as metal which is hardly deformed (flexural modulus: 20 × 10 ⁴ kgf / cm ^2).
Above), and is integrated with the housing 4 in a state where a part thereof is embedded in the housing 4.

On the other hand, the reference hole 6 is formed in an inversely tapered shape so that the positioning pin 5 can be fitted therein, and its opening is, as shown in FIG. Since it is sufficiently wide, a displacement amount caused by deformation of the housing 4 can be allowed.

For this reason, the positioning of the positioning pin 5 and the reference hole 6 when the housing 4 is mounted on the circuit board 1 is relatively easy, and such a positioning pin 5 is inserted deeply into the reference hole 6. The positioning pin 5 is fixed at a predetermined position in the reference hole 6 by pushing the housing 4
Is corrected.

The positioning pin 5 and the reference hole 6 are
It is preferable to arrange in the main scanning direction at a pitch of 5 mm to 100 mm. For example, when configuring an A3 size optical printer head, three to sixty positioning pins 5 are provided on both sides of the lens array 3 in the longitudinal direction of the housing 4. Are arranged, and the same number of reference holes 6 are provided in the circuit board 1.

A plurality of clips 7 are used to hold the housing 4 and the circuit board 1 integrally and to maintain the shape of the housing 4.

The clip 7 is formed by forming a predetermined plate body made of stainless steel or the like into a substantially U-shape by sheet metal working. Both ends of the clip 7 are engaged with the upper surface of the housing 4 and provided near the center. By pressing the lower surface of the circuit board 1 toward the lens array 3 with the bent portion 7a, the reference surface 4a of the housing 4 is brought into close contact with the upper surface of the circuit board 1 and the positioning pin 5 is fitted into the reference hole 6. While maintaining the state, the housing 4 and the circuit board 1 are integrally held.

By integrally holding the circuit board 1 and the housing 4 using such a leaf spring-like clip 7, the contact state between the reference surface 4a and the upper surface of the circuit board, and
The fitting state between the positioning pin 5 and the reference hole 6 can be reliably realized by a relatively simple configuration.

If the clip 7 is attached so as to correspond to the position of the positioning pin 5, the force from the clip 7 can be effectively applied to the positioning pin 5, and the positioning pin 5 is used as a reference. There is also an advantage that the hole 6 can be securely fitted. Therefore, the clip 7
It is preferable to attach the cable corresponding to the position of the positioning pin 5.

Thus, the optical printer head described above selectively emits the light emitting elements 2a of the light emitting element array chip 2 individually in accordance with the image data, and emits the emitted light to the outside through the lens array 3. It functions as an optical printer head by irradiating and forming an image on a body and forming a predetermined latent image on a photoconductor.

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

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, if the arrangement pitch of the positioning pins 5 arranged on both sides of the lens array 3 is set according to the distance from the lens array 3, the positioning pins 5 and the reference holes 6 are provided. Are arranged on both sides of the lens array 3 in a well-balanced manner in accordance with the magnitude of the contraction stress applied to the housing 4, so that the number of the positioning pins 5 and the reference holes 6 can be minimized.
It is possible to effectively prevent the configuration of the optical printer head from becoming complicated.

In the above-described embodiment, the housing 4 and the positioning pin 5 are formed of different materials, and the two are integrated by combining them. However, the housing 4 and the positioning pin 5 may be replaced with each other. The same material may be integrally molded.

Further, in the above embodiment, the positioning pin 5
To the reference surface 4b of the housing 4 and the reference hole 6 to the circuit board 1.
Alternatively, the positioning pin 5 may be provided on the circuit board 1 side, and the reference hole 6 may be provided on the reference surface 4b of the housing 4.

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. Applicable.

[0046]

According to the optical printer head of the present invention, on a circuit board on which a plurality of light-emitting element array chips are mounted in a line, a resin-made resin holding a lens array above the light-emitting element array chips is provided. Is arranged such that the reference surface provided at the lower portion thereof is in contact with the upper surface of the circuit board, and the reference surface of the housing and the row of the light emitting element array chips are arranged on one of the upper surface of the circuit board. A plurality of positioning pins arranged along the other, a plurality of reference holes each having an opening larger than the tip of the positioning pin are provided on the other side, and the positioning pins are inserted into the reference holes while the housing is elastically deformed. Is fixed at a predetermined position, deformation such as curvature or constriction generated during molding of the housing is corrected, and the straight line of the lens array attached to the housing is corrected. It is possible to form a high. Therefore, when using the optical printer head, the light from the light emitting element array chip is accurately imaged on the surface of the photoconductor,
A good latent image corresponding to the image data can be formed.

According to the optical printer head of the present invention,
If the lens array is inserted into the opening of the housing that has been corrected to a desired shape, the labor required for mounting the lens array is significantly reduced, and there is an advantage that the productivity of the optical printer head is improved.

Further, according to the optical printer head of the present invention,
By arranging the positioning pins in a row on both sides of the lens array and setting the arrangement pitch of these positioning pins in accordance with the distance from the lens array, the positioning pins and the reference holes can reduce the shrinkage stress applied to the housing. Since the lenses are arranged on both sides of the lens array in a well-balanced manner according to the size, the above-described effects can be obtained with the minimum number of positioning pins and reference holes.

Further, according to the optical printer head of the present invention, the circuit board and the housing described above are integrally held by a leaf spring-shaped clip for pressing the circuit board toward the lens array, so that the reference of the housing is maintained. The surface can be pressed against the upper surface of the circuit board with a simple structure, and the structure of the optical printer head can be effectively prevented from becoming complicated.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view of an optical printer head according to an embodiment of the present invention.

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

FIG. 3 is an enlarged view of a main part for explaining the movement of a positioning pin.

FIG. 4 is a sectional view of a conventional optical printer head.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Circuit board, 2 ... Light emitting element array chip, 3
... Lens array, 4 ... Housing, 5 ... Positioning pin, 6 ... Reference hole

Claims (5)

[Claims] 1. A reference board having a resin housing for holding a lens array above a light emitting element array chip on a circuit board on which a plurality of light emitting element array chips are mounted in a line. An optical printer head having a surface arranged in contact with an upper surface of a circuit board, wherein the plurality of light printer element arrays are arranged along a row of light emitting element array chips on one of the reference surface of the housing and the upper surface of the circuit board. The two positioning pins were provided on the other side with a plurality of reference holes having openings larger than the tip of the positioning pins, and the positioning pins were fixed at predetermined positions in the reference holes in a state where the housing was elastically deformed. An optical printer head, characterized in that: 2. The resin forming the housing has a flexural modulus of 1.0 × 10 ⁴ kgf / cm ^{2 to} 20 × 10 ⁴ kgf.
^2. The optical printer head according to claim 1, wherein the optical printer head is / cm ² . 3. The optical printer head according to claim 1, wherein said positioning pin is formed in a tapered shape, and said reference hole is formed in an inverted taper shape in which said positioning pin can be fitted. 4. The positioning pins are arranged on both sides of the lens array, one row at a time, and the pitch of the positioning pins forming one row and the pitch of the positioning pins forming the other row are different from each other. The optical printer head according to claim 1, wherein the optical printer head is set according to a distance from the optical printer. 5. The optical printer head according to claim 1, wherein the circuit board and the housing are integrally held by a leaf spring-shaped clip for pressing the circuit board toward the lens array.