JP2001162862A - Optical printer head - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical printer head capable of maintaining a binding strength of a rod lens array to a housing in a high level without enlarging the external dimensions thereof. SOLUTION: An optical printer head is so constituted that a substrate 1 having a light emitting element array chip 2 mounted thereon is housed in a housing 4 having an opening 5, to which the rod lends array 3 is inserted is such a manner that the opening 5 is placed above the light emitting element array chip 2. A cutout 6 is formed on a portion from the top face of the housing 4 in close proximity to the opening 5 to the inner face of the opening 5, and the rod lens array 3 is bonded to be fixed to the housing 4 by coating adhesives 7 to side faces of the cutout 6 and rod lens array 3.

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 such a conventional optical printer head, for example, as shown in FIG. 5, a housing 14 having an opening 15 into which a rod lens array 13 is inserted is provided.
There is known a structure in which a substrate 11 on which a plurality of LED array chips 12 are linearly arranged and mounted is accommodated such that the opening 15 is located right above the LED array chip 12, The light-emitting diode elements 12a of the LED array chip 12 are selectively and individually lit according to image data from the outside, and the radiated light is irradiated to an external photoconductor P via a rod lens array 13, By forming a predetermined latent image on the photoconductor P, it functions as an optical printer head. Then, the latent image formed on the photoconductor P 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.

Incidentally, the rod lens array 13 is fixed to the housing 14 with the rod lens array 13 fitted in the opening 15 of the housing 14 and the upper surface of the housing 14 close to the opening 15 and the rod lens array 13.
The adhesive 16 is applied to the side surface of the substrate.

[0005]

However, in the above-described conventional optical printer head, the adhesive 16 is applied to the upper surface of the housing 14 close to the opening 15 and the side surface of the rod lens array 13 so that the rod lens array is formed. 13 is fixed, the adhesive 1 for the rod lens array 13 and the housing 14 is used.
No. 6 has a small adhered area and tends to have insufficient adhesive strength. For this reason, when heat or vibration is repeatedly applied from other devices incorporated in the electrophotographic printer, the adhesive 16 is peeled off from the rod lens array 13 or the housing 14, and the rod lens array 13 is stably fixed. It has the drawback that it is impossible to keep it.

Therefore, in order to solve the above-mentioned drawback, an adhesive 16 adjusted to a low viscosity is poured into a gap between the rod lens array 13 and the inner surface of the opening 14 so that the adhesive 16 is removed from the side of the rod lens array 13 and the opening 15. May be applied over a large area to the inner surface of the substrate.

However, when the low-viscosity adhesive 16 is poured into the gap between the rod lens array 13 and the inner surface of the opening 14, the excess of the adhesive 16 is
3 may accumulate in the vicinity of the lower end, and a part thereof may adhere to the lower surface of the rod lens array 13. in this case,
Since a part of the light emitted from the LED array chip 12 is blocked by the adhesive 16 adhered to the lower surface of the rod lens array 13, the light cannot be irradiated on the photoconductor P, and an accurate light corresponding to the image data can be obtained. A drawback that a latent image cannot be formed is induced.

[0008]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned drawbacks. An optical printer head according to the present invention comprises a light emitting element array provided inside a housing having an opening into which a rod lens array is inserted. An optical printer head, in which a substrate on which a chip is mounted is accommodated such that the opening is located on the light emitting element array chip, wherein a notch is formed from an upper surface of the housing close to the opening to an inner surface of the opening. The rod lens array is bonded and fixed to the housing by forming an adhesive and applying an adhesive to both the cutout portion and the side surface of the rod lens array.

The optical printer head according to the present invention is characterized in that the inner surface of the opening is tapered downward from near the lower end of the rod lens array.

[0010]

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 according to an embodiment of the present invention, and FIG. 2 is an enlarged view of a main part of FIG.
1 is a substrate, 2 is an LED array chip as a light emitting element array chip, 3 is a rod lens array, 4 is a housing, 5 is an opening, 6 is a cutout portion, and 7 is an adhesive.

The substrate 1 is made of an electrically insulating material such as glass or ceramic.
And a support base material for supporting a circuit pattern (not shown), a driver IC, and the like.

When the substrate 1 is made of, for example, glass, it is manufactured by forming a plate having a predetermined thickness by a conventionally known floating method or the like and cutting the plate into a rectangular shape.

A plurality of LEs are provided on the upper surface of the substrate 1.
D array chips 2 are linearly arranged and mounted.

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 the power supply is applied via the circuit pattern described above, 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.

The substrate 1 on which the LED array chip 2 is mounted on the upper surface is housed inside the housing 4.

The housing 4 has an opening 5 directly above the LED array chip 2, and the rod lens array 3 is fixed in a state where the rod lens array 3 is fitted into the opening 5 so that the rod lens array 3 is fixed to the LED array chip. It holds the LED array chip 3 at a predetermined position on the chip 2 and seals the space in which the LED array chip 3 is arranged.

In this embodiment, the housing 4 includes a base portion 4a on which the substrate 1 is mounted and a cover portion 4b which is mounted on the substrate 1 and provided with an opening 5, both of which are leaf spring-shaped. The substrate 1 is fixed in a state where the substrate 1 is sandwiched by the locking members 8.

The housings 4a and 4b are formed in a predetermined shape by injection molding a plastic material such as a liquid crystal polymer.

On the other hand, the rod lens array 3 fitted into the opening 5 of the housing 4 is an erect equal-magnification type lens, and has a large number of linearly arranged rod-shaped lenses 3a or a staggered arrangement. Frame rods 3a
b.

Since the rod lens array 3 is located on the light emitting surface of the LED array chip 2, when the light emitting diode element 2a of the LED array chip 2 emits light,
The light is irradiated and imaged on the external photoconductor P.

The rod lens array 3 is fixed to the housing 4 with an adhesive 7.

Specifically, from the upper surface of the housing 4 close to the opening 5 into which the rod lens array 3 is inserted, the opening 5
A notch 6 having a C-plane cut shape is formed over the inner surface of the rod lens array 3, and an adhesive 7 is applied to both the notch 6 and the side surface of the rod lens array 3 so as to surround the rod lens array 3. Thus, the rod lens array 3 is bonded and fixed to the housing 4.

In this embodiment, the notch 6 is provided so as to form a plane inclined at an angle θ of, for example, 15 ° to 75 ° with respect to the upper surface of the housing 4. The adhesive 7 is formed between the side surfaces of the array 3 in a shape of a mountain-like swelling due to surface tension.

In this case, the area of the adhesive 7 applied to the side surface of the rod lens array 3 and the housing 4 can be made larger than that of the conventional example shown in FIG. 3 without increasing the outer dimensions of the optical printer head. Housing 4
Therefore, even if heat or vibration is repeatedly applied from other devices incorporated in the electrophotographic printer when the optical printer head is used or the like, the bonding strength of the rod lens array 3 is maintained high. The rod lens array 3 can be stably fixed without any peeling of the agent 7, and the reliability of the optical printer head can be improved.

If the inner surface of the opening 5 is formed so as to taper downward from the vicinity of the lower end of the rod lens array 3, the adhesive 7 adjusted to have a low viscosity as shown in FIG. Is poured into the gap between the rod lens array 3 and the inner surface of the opening 5 to apply the adhesive 7 to the rod lens array 3 and the housing 4 over a wider area. Flows through the inner surface of the housing 4 and hardly accumulates near the lower end of the rod lens array 3, effectively preventing a part of the adhesive 7 from adhering to the lower surface of the rod lens array 3. it can. Therefore, the LED array chip 2
The light from the light emitting diode element 2a always satisfactorily irradiates the photoconductor P, thereby making it possible to form an accurate latent image corresponding to the image data.

Further, in this case, since the adhesive 7 is applied so as to surround the rod lens array 3,
The gap between the rod lens array 3 and the opening 5 is satisfactorily sealed with an adhesive 7, so that ozone gas (O ₃ ) or toner generated during the electrophotographic process enters the inside of the housing 4. Therefore, it is possible to effectively prevent the light emitting diode element 2a from being corroded or adhered to the surface of the light emitting diode element 2a and contaminating the light emitting diode element 2a, thereby further improving the reliability of the optical printer head.

Further, if the light absorption of the adhesive 7 is adjusted to 10% or less by adding a predetermined amount of a pigment or a dye to the adhesive 7, the light emitted from the light emitting diode element 2a can be reduced to a rod lens array. Since there is no leakage from the gap between the housing 3 and the housing 4, unnecessary light is not irradiated to the photoconductor P, and a more accurate latent image corresponding to the image data can be formed. Therefore, it is preferable to set the light absorption of the adhesive 7 to 10% or less.

Thus, the above-described optical printer head is
A predetermined electric power is applied to the light emitting diode elements 2a of the ED array chip 2 in accordance with the image data, and the light emitting diode elements 2a are selectively and individually emitted, and the emitted light is externally transmitted through the rod lens array 3. Photoconductor P
By irradiating and forming an image on the photoconductor P, a predetermined latent image is formed on the photoconductor P, thereby functioning as an optical printer head.

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 housing 4 is constituted by the base portion 4a and the cover portion 4b. Instead, however, the housing 4 may be integrally formed, or may be constituted by three or more members. It does not matter.

In the above-described embodiment, the notch 6 of the housing 4 is formed in a C-plane. Alternatively, the notch 6 may be formed in a concave curved surface as shown in FIG. Alternatively, it may be formed in an L-shaped cross section as shown in FIG.

Further, in the above-described embodiment, the adhesive 7 is applied so as to surround the rod lens array 3. However, the adhesive 7 may be partially applied instead. The notch 6 of the housing 4 is partially formed only at a position where the adhesive 7 is applied.

In the above embodiment, the LED array head has been described as an example. However, the present invention can be applied 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. is there.

[0035]

According to the optical printer head of the present invention, a notch is formed from the upper surface of the housing close to the opening into which the rod lens array is inserted to the inner surface of the opening. Since the rod lens array was bonded and fixed to the housing by applying an adhesive to both sides,
The adhesive area of the adhesive to the side surface of the rod lens array and the housing can be increased without increasing the external dimensions of the optical printer head, and the bonding strength of the rod lens array to the housing can be maintained high. . Thus, even when heat or vibration is repeatedly applied from other devices incorporated in the electrophotographic printer when the optical printer head is used, the rod lens array is stably fixed without any peeling of the adhesive. Therefore, the reliability of the optical printer head can be improved.

According to the optical printer head of the present invention,
By forming the inner surface of the opening so as to taper downward from the vicinity of the lower end of the rod lens array, the adhesive adjusted to have a low viscosity is poured into the gap between the rod lens array and the inner surface of the opening. If the adhesive is to be applied over a larger area to the rod lens array or the housing, much of the excess adhesive will flow along the inner surface of the housing and accumulate near the lower end of the rod lens array. And it is possible to effectively prevent a part of the adhesive from adhering to the lower surface of the rod lens array. Accordingly, the light of the LED array chip is always satisfactorily irradiated on the photoreceptor, thereby making it possible to form an accurate latent image corresponding to the image data.

[Brief description of the drawings]

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

FIG. 2 is an enlarged view of a main part of FIG.

FIG. 3 is an enlarged view of a main part showing a flow of the adhesive when the rod lens array is fixed using a low-viscosity adhesive.

4A and 4B are enlarged views of a main part of an optical printer head according to another embodiment of the present invention.

FIG. 5 is a sectional view of a conventional optical printer head.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... board | substrate, 2 ... LED array chip as a light emitting element array chip, 3 ... rod lens array, 4
... Housing, 5 ... Opening, 6 ... Notch, 7 ... Adhesive

Claims (2)

[Claims] A substrate having a light emitting element array chip mounted therein is accommodated in a housing having an opening into which a rod lens array is inserted so that the opening is positioned on the light emitting element array chip. An optical printer head, wherein a notch is formed from an upper surface of the housing close to the opening to an inner surface of the opening, and an adhesive is applied to both the notch and the side surface of the rod lens array. An optical printer head comprising a lens array bonded and fixed to a housing. 2. The optical printer head according to claim 1, wherein the inner surface of the opening is tapered downward from near the lower end of the rod lens array.