JP2600298Y2 - Structure of LED array print head - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure of an LED array print head used as a light source of an exposure section in an electrophotographic printer or the like.

[0002]

2. Description of the Related Art In general, an LED array print head of this type has a plurality of LED chip arrays having light emitting elements on the upper surface arranged in a line on an upper surface of a head substrate, and a lower surface of the head substrate. In addition, a metal heat sink is provided, and a hollow synthetic resin cover body having a rod-shaped rod lens array extending in the column direction of each LED chip array is provided on the upper surface side of the head substrate. Then, the cover body and the heat radiating plate are fastened with the head substrate interposed therebetween.

When assembling the LED array print head, each LED mounted on the head substrate is required.
It is necessary to position the rod lens array in the cover body so as to exactly match the light emitting element in the ED chip array. Conventionally, positioning pins having a round cross section are integrally formed on both left and right ends of a mounting surface of the cover body with respect to the head substrate, while each of the positioning pins is fitted to the head substrate and the heat sink. A round pin hole is formed so that the head substrate and the heat radiating plate are fitted to the cover body, and the respective pin holes in the head substrate and the heat radiating plate are fitted to the positioning pins in the cover body. By assembling, the three members are positioned at the time of assembly.

[0004]

[Problems to be Solved by the Invention] However, the diameter of the positioning pin formed integrally with the cover body made of synthetic resin,
And, since there is variation in the inner diameter of the pin hole formed in the head substrate, the fitting of the pin hole to the positioning pin is caused by the variation in the size.
It can be hard or loose.

If the pin holes are firmly fitted to the positioning pins, the pin holes in the head substrate cannot be easily fitted to the roots of the positioning pins in the cover body. As a result, the distance between the light emitting element in each LED chip array and the rod lens array in the cover body deviates from a predetermined value, and the lens focuses. This leads to the problem of blurring.

In order to avoid this problem, the fitting tolerance of the pin hole of the head substrate with respect to the positioning pin of the cover body may be increased. However, if the fitting tolerance is increased, the pin hole of the positioning pin may be reduced. Due to the backlash, the light emitting element in each LED chip array on the head substrate side and the rod lens array on the cover body side,
This causes a problem that the rod lens array is displaced in a direction perpendicular to the longitudinal direction.

It is a technical object of the present invention to prevent these problems from occurring.

[0008]

In order to achieve the above technical object, the present invention provides a method comprising: a cover body provided with a rod lens array, a heat radiating plate, and a plurality of LED chip arrays arranged on the upper surface in a row. closely the head substrate mounted on Jo
Between the mounting surface of the cover body and the head substrate, at least on both the left and right sides .
A pin hole formed in the head substrate, and a hole formed in the heat sink.
In the LED array print head, wherein the positioning pins that fit into both the pin holes are protruded , each of the positioning pins has a pin hole whose outer peripheral surface is formed in the head substrate.
And close to the inner peripheral surface of the pin hole formed in the heat sink.
A plurality of recessed grooves are formed on the outer peripheral surface of each positioning pin , and each recessed groove extends along the axial direction of each positioning pin.
To extend to the root of the positioning pin . ".

[0009]

[Operation] As described above, each positioning pin is connected to its outer periphery.
The surface is in the pin hole drilled in the head substrate and the heat sink.
This pin is configured to be in close contact with the inner peripheral surface of the
A plurality of dent grooves are formed on the outer peripheral surface of each positioning pin.
Recessed grooves are located along the axial direction of each positioning pin.
By engraving so as to extend to the root of the head substrate, both the head substrate and the heat radiating plate can be accurately and reliably positioned with respect to the cover body without play, while the head substrate side with respect to the positioning pins Even when the fitting of each pin hole is firm, this firm fitting can be absorbed and relaxed by each of the recessed grooves, and each pin hole on the head substrate side is connected to each positioning pin on the cover body side. On the other hand, the positioning pins can be easily and reliably fitted to the roots of the positioning pins with a light force.

[0010]

[Effect of the Invention] Therefore, according to the present invention, the cover body side
Each positioning pin, each pin hole on the head substrate side, and the cover body side
The fitting tolerance between each positioning pin
Make sure that the outer circumference of the pin is in close contact with the inner circumference of each pin hole.
Under the reduced condition, cover each pin hole on the head substrate side.
Make sure that the positioning pins on the bar
Therefore, when assembling the head substrate and the heat radiating plate to the cover body , the lens focus in the rod lens array is shifted, and the light emitting element in each LED chip array on the head substrate side and the rod lens array on the cover body side This has the effect of greatly reducing the occurrence of a displacement in the direction perpendicular to the longitudinal direction of the rod lens array during this.

[0011]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. In the figure, reference numeral 1 denotes a head substrate made of ceramic or glass epoxy resin, and reference numeral 2 denotes the head substrate 1.
A heat sink made of metal such as aluminum disposed on the lower surface of the head substrate 1; and a reference numeral 3 denotes a hollow synthetic resin cover disposed on the upper surface of the head substrate 1.
Is provided with a rod lens array 4 configured in a rod shape.

With the heat sink 2 and the cover 3 interposed therebetween with the head substrate 1 interposed therebetween, engagement holes 5 at both ends of a leaf spring fastener 5 formed in a substantially U-shape.
The engagement protrusions 6 and 7 integrally formed on the left and right side surfaces of the cover body 3 are respectively engaged with and affixed to a and 5b so as to be detachably fastened. On the other hand, on the upper surface of the head substrate 1, a plurality of LED chip arrays 8 each having a light emitting element portion are mounted in a line along the longitudinal direction of the rod lens array 4, and each LED chip Driving ICs 9 for each of the arrays 8 are mounted in a row.

A thin metal wire 10 is used for wire bonding between each of the LED chip arrays 8 and each of the driving ICs 9. Further, the upper surface of the head substrate 1, the surface of each LED chip array 8, and each driving IC
A thin resin coating 11 is formed on the surface of C9 by applying a transparent synthetic resin liquid. When the radiator plate 2 and the cover body 3 are fastened by the fastening body 5 with the head substrate 1 sandwiched therebetween, both right and left sides of the mounting surface 3a of the cover body 3 with respect to the head substrate 1 The positioning pins 12, 13 having a round cross section are integrally formed at the portion of the head substrate 1, while the positioning pins 12, 13 are in close contact with the head substrate 1.
Then, round pin holes 14 and 15 are formed, and the heat radiation plate 2 is also provided with pin holes 16 and 17 in which the respective positioning pins 12 and 13 are fitted closely. The pin holes 16 and 17 may be formed as long holes that are long in the longitudinal direction of the rod lens array 4). Each of the pin holes 14, 15, in the head substrate 1 and the heat sink 2,
By assembling each of the positioning members 16 and 17 so as to be fitted to each of the positioning pins 12 and 13 of the cover body 3, the positioning of the rod lens array 4 in the X-axis direction parallel to the longitudinal direction and the rod The lens array 4 is configured to simultaneously perform positioning in the Y-axis direction perpendicular to the longitudinal direction.

In this case, each of the positioning pins 1
As shown in FIG. 5, four concave grooves 18 are formed on the outer peripheral surfaces of the positioning pins 2 and 13 in the axial direction of the positioning pins.
It is engraved so as to extend to the root of the positioning pin . In this manner, a plurality of concave grooves 18 are formed on the outer peripheral surface of each positioning pin 12, 13 on the cover body 3 side so that each concave groove 18 extends along the axial direction of the positioning pin to the root of the positioning pin. Even if the pin holes 14, 15 on the head substrate 1 side are firmly fitted to the positioning pins 12, 13, the rigid fitting is performed by the plurality of recessed grooves 18. By
Since the pin holes 14 and 15 on the head substrate 1 side can be absorbed and alleviated, the positioning pins 1 and 2 on the cover body 3 side
It is possible to easily and securely fit the base portions 2 and 13 with a light force.

Since the positioning in the Y-axis direction out of the X-axis direction and the Y-axis direction requires higher accuracy than the positioning in the X-axis direction, each of the positioning pins 1 is required.
The plurality of concave grooves provided on the outer peripheral surfaces of the grooves 2 and 13 may be configured as a pair of left and right concave grooves 18a having a form as shown in FIG.
As shown in FIG. 7, it may be configured in a form divided into four by a concave groove 18b, or as shown in FIG. 8, may be configured in a form divided into two by a concave groove 18c. It is good.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view of an LED array printhead according to an embodiment of the present invention.

FIG. 2 is an enlarged sectional view taken along line II-II of FIG.

FIG. 3 is a view of an assembled state of FIG. 2;

FIG. 4 is a side view taken along the line IV-IV of FIG. 1;

FIG. 5 is a perspective view showing a positioning pin.

FIG. 6 is a perspective view showing another example of a positioning pin.

FIG. 7 is a perspective view showing another example of a positioning pin.

FIG. 8 is a perspective view showing another example of a positioning pin.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Head board 2 Heat radiating plate 3 Cover body 3a Mounting surface with respect to the head board in a cover body 4 Rod lens array 5 Fastening body 8 LED chip array 9 Driving IC 12,13 Positioning pin 14,15 Pin hole in head board 16,17 Radiation Pin holes 18, 18a, 18b, 18c in plate

Claims (1)

(57) [Scope of request for utility model registration] A cover having a rod lens array;
A heat sink is fastened in such a manner that a head substrate having a plurality of LED chip arrays mounted on the upper surface thereof in a row is sandwiched therebetween, and a mounting surface of the cover body with respect to the head substrate. At least the left and right sides, the header of the
A pin hole formed in the substrate and a pin formed in the heat sink.
LED with protruding positioning pins that fit into both holes
In the array print head, each of the positioning pins has an outer peripheral surface on the head substrate.
Inner circumference of the drilled pin hole and the drilled pin hole
A plurality of concave grooves are engraved on the outer peripheral surface of each positioning pin so that each concave groove extends along the axial direction of each positioning pin to the root of the positioning pin. A structure of an LED array print head, characterized in that: