JPH0820133A - Method and apparatus for assembling led print head - Google Patents

Abstract

PURPOSE:To assemble an LED print head without generating large errors and dispersion in set distances from an LED element to each part and to improve the quality of an image. CONSTITUTION:Positioning pins 12, 12 are installed at least on one side of the right and left ends of a radiator plate 10 to project by a specified length from the side. After a head base 13 equipped with an LED element and a lens holder 11 being attached to the radiator plate 10, a lens R, which is engaged vertically movably in the lens fitting groove 11a of the lens holder 11, is held by a lens holding means 3 to face the lens holder 11 and moved vertically. In this way, the lens R is stopped at a specified height which is set on the basis of the height of the positioning pins 12, 12 and glued to the lens holder 11 while being kept stopping.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an LED print head (light emitting diode) used for forming an electrostatic image on the surface of a photosensitive drum of an electrophotographic printer by exposing the surface of the photosensitive drum. The present invention relates to a method of assembling a print head) and an apparatus for the same.

[0002]

2. Description of the Related Art Generally, an LED print head has a structure in which light emitted from a large number of LED elements arranged in a line is converged by a lens. Therefore, when assembling the LED print head, it is necessary to accurately set the mutual distance between the LED element and the lens to a predetermined constant dimension, and if this dimension is not accurate, the resolution of the image becomes poor.

Therefore, conventionally, when assembling the LED print head, a method as shown in FIGS. 9 and 10, for example, has been adopted. That is, in the prior art, as shown in FIG. 9, first, both ends 81 and 81 of the lens R are first brought into contact with the stepped portions 80a and 80b of the lens holder 11e, respectively, and these portions are bonded using an adhesive. Thus, the lens R is previously incorporated in the lens holder 11e. On the other hand, as shown in FIG. 10, positioning pins 12e and 12e are appropriately attached to the left and right ends of the heat dissipation plate 10, and the LED is provided on the surface of the heat dissipation plate 10.
The head substrate 13 provided with elements (not shown) is bonded. Then, the lens holder 11e in which the lens R is incorporated is arranged on the upper side of the head substrate 13 so as to be overlapped with it and attached to the heat dissipation plate 10.

Further, conventionally, after the above assembling work is completed, an LED positioned below the lens R is mounted by a camera C disposed above the central portion a1 in the longitudinal direction of the lens R and the left and right end portions a2 and a3. The device was being imaged. When the captured image of the LED element is unclear, the heights of the positioning pins 12e and 12e are adjusted so that the image is clear within a certain allowable range.

[0005]

However, in the above-described conventional assembling method, since the lens R is fixedly incorporated in the lens holder 11e in advance and then these are attached to the heat dissipation plate 10, the lens R is attached at various places. So-called out-of-focus was likely to occur. That is, in the related art, the lens R may be attached to the lens holder 11e in an inclined state rather than in an exactly horizontal state due to a processing accuracy error of the stepped portions 80a and 80b of the lens holder 11e. Further, due to the warp of the lens R itself, the bending of the lens R due to its own weight due to the support of both ends of the lens R, and the like, each LE of the heat sink 10 or the head substrate 13 is also caused.
There may be a large variation in the distance from the D element to each part of the lens R.

Therefore, conventionally, due to the large mounting error of the lens R as described above, the camera C is mounted after the assembly work of the LED print head is completed.
However, there is a problem that it takes time to adjust the positioning pins 12e and 12e by adjusting the positioning pins 12e and 12e to eliminate the out-of-focus state at various points of the lens R, and it takes a long time.

Further, there is a certain limit in focusing the various parts of the lens R only by adjusting the positioning pins 12e, 12e, and when there are large variations in the various parts of the lens R, the positioning pins 12e, 12e are not always removed. It is not always possible to appropriately correct the above variation by adjustment. Therefore, in such a case, there is a problem that the focus adjustment of the lens R cannot be appropriately performed and the image quality cannot be improved. Then, in order to solve this, it is necessary to remove the lens R from the lens holder 11e and then re-bond them, so that a series of assembly work of the LED print head needs to be redone.
There has been a problem that the series of operations is very complicated.

The present invention has been conceived under such circumstances, and an LED print head is assembled so as not to cause a large error or variation in the set distance from the LED element to each part of the lens. This makes it possible to increase the resolution to improve the image quality, eliminate the complicated focus adjustment work after the assembly is completed, or simplify the work even if the adjustment work is performed. The task is to improve the work efficiency of.

[0009]

SUMMARY OF THE INVENTION The present invention does not assemble the respective parts of the LED print head on the premise that the focusing adjustment work using the positioning pins is carried out after the assembly is completed as in the prior art, but the lens is positioned by the positioning pins. Based on the completely new idea that the burden required for complicated focusing work after assembly work can be reduced by accurately mounting and fixing the lens to the predetermined height based on the height of the It was invented in.
In order to solve the above problems, the present invention takes the following technical means.

That is, according to the invention of claim 1 of the present application, a positioning pin is mounted so as to project by a predetermined dimension on at least one side of the left and right ends of the heat dissipation plate, and the heat dissipation plate is provided with a head substrate and an LED element. After the lens holder is attached, the lens that is vertically movable in the lens mounting groove of the lens holder is held by the lens holding means and is raised or lowered by being opposed to the lens holder to move the lens. It is characterized in that the positioning pin is set to a predetermined height based on the height of the positioning pin and stopped, and then the lens is bonded to the lens holder in this stopped state.

The step of setting the lens to a predetermined height based on the height of the positioning pin is to hold the lens by the lens holding means and maintain it at a constant height, and then set the lens to that height. By pressing the tip end portion of the positioning pin while maintaining it at the above, it is possible to lower or raise the heat dissipation plate to which the lens holder and the head substrate are attached by a predetermined dimension (claim 2).

According to a third aspect of the present invention, in the method of assembling the LED printhead according to the first or second aspect, the lens holding means has upper surfaces at least at a central portion and left and right end portions in the longitudinal direction of the lens. Is a suction head for suction-holding in a flush state.

The invention according to claim 4 of the present application is an LED print head assembling apparatus for carrying out the method for assembling the LED print head according to claim 1, wherein L
A mount holder that can be moved up and down for mounting and holding the heat sink of the ED print head, and is fitted into the lens mounting groove of the lens holder mounted on the heat sink mounted and held on the mount holder. And a lens holding means that is detachably attached to the lens and that is movable up and down so that the held lens can be held at a constant height. When maintained at the above position, the tip end of the positioning pin protruding to the upper surface side of both left and right ends of the heat dissipation plate is pressed from above and the heat dissipation plate on the above-mentioned holding holder is set to a predetermined constant size. It is characterized in that it is provided with a pressing means for the positioning pin to be lowered.

[0014]

According to the invention described in claim 1, the lens fitted vertically in the lens mounting groove of the lens holder attached to the heat dissipation plate is based on the height of the positioning pin. After setting to a predetermined height,
Since this lens is adhered to the lens holder, unlike the conventional method in which the lens is assembled to the lens holder and then these are attached to the heat sink, the LED print head can be installed regardless of the processing error of the lens holder. The actual height of the lens in the assembled state can be accurately set to a predetermined height with reference to the height of the positioning pin.
Therefore, the LED of the head substrate mounted on the heat sink
The distance from the element to each part of the lens can also be accurately set to a predetermined dimension, and the dimension error can be reduced.

As a result, L having high resolution and good quality
ED print head can be manufactured and LED
It is possible to eliminate the need for complicated focusing work after the print head is assembled, and even if the focusing work is performed, the focusing work will be easier than before and the efficiency of a series of work will be improved. The special effect of being able to raise it is acquired.

According to the third aspect of the present invention, when the lens fitted in the lens mounting groove of the lens holder is held by the suction head as the lens holding means and maintained at a constant height, The upper surfaces of at least the central portion and the left and right end portions in the longitudinal direction can be set to be flush with each other. Therefore, it is possible to prevent the center portion of the lens from being bent due to the weight of the lens or the like, and it is possible to maintain the lens in a horizontal state and bond it to the lens holder. As a result, the height of the central portion of the lens is less than that of the both ends, and it is possible to reduce the variation in the set distance from the LED element to each portion of the lens, thereby further improving the quality of the LED print head. The effect of being able to be obtained is obtained.

In the invention described in claim 4, first, L
After the heat dissipation plate of the ED print head is placed and maintained on the mount holder which can be raised and lowered, the lens fitted into the lens mounting groove of the lens holder attached to the heat dissipation plate is attracted by the lens holding means. It can be held and maintained at a constant height. Then, after that, in a state in which the lens is maintained at a constant height, by pressing the tip end portion of the positioning pin projecting to the upper surface side of the left and right ends of the heat dissipation plate by the pressing means for the positioning pin, The heat dissipation plate can be lowered by a predetermined constant size. Thereby, the distance from the LED element of the head substrate attached to the heat dissipation plate to the lens can be accurately set. If the lens is adhered to the lens holder in this state using an adhesive or the like, the lens can be fixed and the LED print head can be assembled. Therefore, the method of assembling the LED print head according to the first aspect can be properly implemented, and the same effect as that described above with respect to the invention of the first aspect can be expected.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The preferred embodiments of the present invention will be described below.
A specific description will be given with reference to the drawings.

FIG. 1 is a partially sectional front view showing an example of an LED print head assembling apparatus according to the present invention, and FIG. 2 is a side view thereof.

In FIG. 1, this assembling apparatus is provided with a mount holder 2 for mounting and holding the heat dissipation plate 10 of the LED print head 1, and is arranged above the mount holder 2 so as to be movable up and down. Suction head 3 as a lens holding means, and a pair of left and right pressing bodies 4 as pressing means for positioning pins arranged on both the left and right sides of the suction head 3.
4 is provided.

As shown in FIG. 2, the above-mentioned mount holder 2 is
A positioning step portion 22 and a clamp piece 21 for clamping and fixing the heat dissipation plate 10 of the LED print head 1 in the width direction are provided on the upper surface portion thereof. The clamp piece 21 is provided so as to be reciprocally movable along the direction of the arrow a by the cylinder 20 or the like.
The heat dissipation plate 10 can be clamped by advancing and pressing the front end face portion of the heat dissipation plate 10. Further, a plurality of guide shafts 24 provided upright on a flat plate-shaped base 23 are inserted into the mounting and holding base 2, and the mounting and holding is performed between the base 23 and the mounting and holding base 2. A spring 25 is interposed to constantly urge the base 2 upward. As a result, the mounting and holding base 2 can be raised and lowered while maintaining the horizontal state.

In FIG. 1, the lower end surface of the suction head 3 is formed as a horizontal surface, and a plurality of small-hole-shaped intake holes 30 are formed on the lower end surface of the suction head 3 in series at regular intervals. It is provided. The upper part of the suction head 3 is connected to the suction side of the blower 5 (including a vacuum pump) by piping, and a negative pressure is generated in the plurality of suction holes 30 by the suction action of the blower 5, and the LED print head 1 The lens R constituting the above can be held by vacuum suction. The suction head 3 is supported by, for example, rods 61a of cylinders 61, 61 mounted on a suitable frame 60.
By the operation of 1, it can be raised and lowered to an arbitrary height while maintaining the horizontal state.

Further, as shown in FIGS. 3 and 4, concave groove portions 33a to 33c for applying an adhesive are provided on the front side of each of the central portion and the left and right ends of the suction head 3 in the longitudinal direction. There is. These concave groove portions 33a to 33c are
This is a part that serves as an injection port of an adhesive when the lens R of the LED print head 1 is adhered to the lens cover 11 in the assembly work process described later.

Each of the pair of pressing bodies 4 and 4 presses down the positioning pins 12 and 12 which are attached so as to project from the left and right ends of the heat dissipation plate 10 mounted on the mounting and holding base 2. The linear motors 40, 40 serving as reciprocating motion sources are attached to the tips of the reciprocating rods. Each of these linear motors 40 is attached to the left and right ends of the plate 34 attached to the upper part of the suction head 3, and when the suction head 3 moves up and down, the pressing bodies 4 and 4 move up and down together. It is supposed to do. However, even when the raising / lowering operation of the suction head 3 is stopped, it is possible to raise / lower these pressing bodies 4 and 4 independently by operating the linear motor 40. When the pressing bodies 4 and 4 are individually moved up and down, the linear motor 40 accurately lowers the moving stroke of the pressing bodies 4 and 4 by a predetermined constant dimension with reference to the lower end surface of the suction head 3. It is configured so that it can be controlled.

Next, an example of the method of assembling the LED print head according to the present invention using the LED print head assembling apparatus having the above-described structure will be described.

First, as shown in FIG. 5, positioning pins 12 are provided on the left and right ends of the heat sink 10 of the LED print head 1.
The protrusions S (height S) of the positioning pins 12 are accurately set to predetermined constant dimensions. As a setting method, as shown in FIG.
After being clamped by 2a, the height S of the positioning pin 12 may be adjusted by rotating the positioning pin 12 while checking the height of the tip of the positioning pin 12 with the dial gauge DG. Further, after adjusting the height S of the positioning pin 12 to a fixed dimension, the nut 64 may be tightened so that the positioning pin 12 does not rotate carelessly.

As described above, the left and right positioning pins 1
After the setting of the heights S of 2 and 12 is completed, as shown in FIG. 6, the head substrate 13,
The flexible substrate 14, the lens holder 11, etc. are attached. In the present invention, these head substrates 13
It goes without saying that the above-described setting work of the height S of the positioning pins 12 and 12 may be performed after the above-mentioned mounting is performed first.

The head substrate 13 is the head substrate 1
3. A large number of LEDs arranged in series along the longitudinal direction
The element 13a and the drive circuit 13b for driving each of the LED elements 13a are mounted, and the element 13a can be attached to the surface of the heat dissipation plate 10 by using an adhesive or the like. The flexible substrate 14 is for supplying electric power and control signals to the head substrate 13.

The lens holder 11 has a through-hole-shaped lens mounting groove 1 into which the lens R is vertically movable.
1a is provided. The lens holder 11 is mounted and fixed to the heat dissipation plate 10 by using a screw body 65 after stacking the lens mounting groove 11a on the head substrate 13 so that the lens mounting groove 11a matches the position of the LED element 13a of the head substrate 13. You can do it.

Lens mounting groove 1 of the lens holder 11
A lens R may be fitted in advance in 1a,
The lens R is not yet adhered to the lens holder 11. The lens R is formed by casting a large number of unit lens bodies 66 in a non-translucent resin mold 67 to form an elongated block shape as a whole.

Then, as described above, the lens holder 1
After mounting the heat radiating plate 10 on which the components 1 and the like have been mounted on the mount holder 2 as described with reference to FIGS. 1 and 2,
It is clamped by the clamp piece 21. After that, for example, a lens pressing jig 7 as shown in FIG. 2 is brought into contact with one side surface of the lens R and pressed. As a result, the lens R that is fitted in the lens mounting groove 11a of the lens holder 11 in a rattling state is inserted into the lens mounting groove 1
The lens R can be positioned in the front-rear width direction along one side surface of the la 1a.

After that, the cylinders 61, 61 are operated and the suction head 3 is lowered by a certain size. Further, at this time, the pressing bodies 4 and 4 located on both sides thereof are also lowered by the same dimension amount as the suction head 3.

When lowering the suction head 3 as described above, first, as shown in FIG. 7, the suction head 3 is placed on the upper surface of the lens R fitted in the lens mounting groove 11a of the lens holder 11. Although they come into contact with each other, the suction head 3 is also lowered by a certain amount thereafter. As a result, not only the heat dissipation plate 10 but also the mounting / holding base 2 moves down against the elastic force of the spring 25. At this time, the flat lower surface of the suction head 3 causes the upper surface of the lens R to move. Each place will be pressed.

Therefore, various portions of the lens R in the longitudinal direction can be pushed to the bottommost positions of the lens mounting groove 11a of the lens holder 11, and the various portions of the upper surface of the lens R can be evenly attracted to the lower surface of the suction head 3. Can be made.
That is, it is possible to properly prevent the lens R from being sucked by the suction head 3 in a bent state.

After the suction head 3 is lowered and stopped as described above, the linear motors 40, 40 are operated while the upper surface of the lens R is suctioned by the suction head 3,
As shown in FIG. 8, the positioning pins 12, 12 of the heat dissipation plate 10 are pressed by the pressing bodies 4, 4 to a predetermined size S.
Press down by 1. Then, not only the heat dissipation plate 10, but also the base substrate 13, the lens holder 11, etc., and all the components other than the lens R sucked by the suction head 3 are lowered by the predetermined dimension S1 together with the mount holder 2.

In the above state, the height of the lens R is set because the upper surface of the lens R is suction-held by the suction head 3. On the other hand, the heat sink 1
The height of the LED element 13a of the base substrate 13 attached to 0 is lower than the height when the suction head 3 is stopped by the dimension amount S1 in which the pressing bodies 4 and 4 push down the positioning pins 12 and 12. ing. That is, in the above series of operations, the height of the lens R is determined by the positioning pin 1
It is possible to set the heights of the tip ends of the reference numerals 2 and 12 as a relative reference to a predetermined height.

Therefore, if the dimensions for lowering the positioning pins 12, 12, that is, the lower dimensions for the pressing bodies 4, 4 are taken into consideration in advance, the lens R and the LE on the base substrate 13 are taken into consideration.
The dimension between the D element 13a and each other can be set to a desired appropriate dimension. Further, since the entire area of the upper surface of the lens R is adsorbed on the flat lower end surface of the adsorption head 3,
The center portion of the lens R will not be bent.

After the dimensions of the lens R and the LED element 13a are set as described above, the lens R may be bonded to the lens holder 11 while maintaining the dimension setting state. . This bonding operation is performed by injecting the adhesive as shown by an arrow b in FIG. 4 from concave grooves 33a to 33c for applying the adhesive, which are provided on the front surface of the suction head 3 shown in FIGS. 3 and 4, for example. , Can be applied. This makes it possible to appropriately bond the central portion and the left and right end portions of the lens R in the longitudinal direction to the corresponding portions of the lens holder 11 by using an adhesive, and set between the lens R and the LED element 13a. It is possible to fix the lens R without causing a change in size. The application of such an adhesive may be performed manually by an operator, but may be performed by mechanization.

After the lens R is adhered to the lens holder 11 as described above and the adhesive is dried, the adsorbing action of the adsorbing head 3 may be released and the lens R may be raised. As a result, the LED print head 1 that has been assembled can be taken out from the mount holder 2.

In the LED print head 1 assembled as described above, since the mutual distance between the lens R and the LED element 13a is set to a predetermined proper dimension, the resolution is high and the image of good quality is obtained. Output can be done.
Further, after completion of the above assembling, in order to ensure the integrity of the product, the camera C shown in FIG. 10 as a conventional example may be used to inspect whether the lens R is properly focused.

In the above embodiment, the lens R is sucked and held by the suction head 3 and maintained at a constant height, and then the tip ends of the positioning pins 12, 12 are pressed by the pressing members 4, 4 by a predetermined dimension. Thus, the lens R is set to a predetermined height based on the height of the positioning pins 12 and 12 (corresponding to claim 2), but the invention according to claim 1 is not limited to this.

According to the first aspect of the present invention, the point is that the lens R is held by the lens holding means, and is raised or lowered relative to the lens holder 11 to bring the lens R into the positioning pins 12, 12. It may be set to a predetermined height based on the height. Therefore, unlike the method of the above-described embodiment, the LED holding device for holding the lens is moved up or down by itself while the positioning pin is kept at a constant height, whereby the LED element on the heat dissipation plate is moved. The distance between the lens and the lens may be set to a predetermined distance.

In addition, according to the present invention, the specific configuration of each part of the LED print head assembling apparatus is not limited to that in the above embodiment, and various design changes are possible.

[Brief description of drawings]

FIG. 1 is a cross-sectional front view of essential parts showing an example of an LED printhead assembling apparatus according to the present invention.

FIG. 2 is a side view of the LED print head assembling apparatus shown in FIG.

3 is a front view of a main part of a suction head in the LED print head assembling apparatus shown in FIG.

FIG. 4 is a sectional view taken along line XX of FIG.

FIG. 5 is a front view showing an example of work for setting the height of a positioning pin attached to a heat dissipation plate.

FIG. 6 is an exploded perspective view of an example of a part to be assembled with a heat dissipation plate.

FIG. 7 is a cross-sectional front view of essential parts showing an example of work steps in the middle of the method for assembling the LED print head according to the present invention.

FIG. 8 is a cross-sectional front view of the main parts, showing another example of the work process in the middle of the method for assembling the LED print head according to the present invention.

FIG. 9 is an explanatory diagram showing an example of a conventional method for assembling an LED print head.

10 is an explanatory diagram showing an example of work after the work of assembling the conventional LED print head shown in FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 LED print head 2 Mounting / holding base 3 Suction head (lens holding means) 4 Pressing body (pressing means for positioning pin) 10 Heat sink 11 Lens holder 11a Lens mounting groove 12 Positioning pin 13 Base substrate 13a LED element R lens

Claims (4)

[Claims] 1. A radiating plate is mounted with projecting positioning pins on at least one side of both left and right ends of the heat radiating plate, and a head substrate having an LED element and a lens holder are mounted on the heat radiating plate. A lens fitted in the lens mounting groove so as to be movable up and down is held by a lens holding means and is raised or lowered relative to the lens holder, so that the lens is predetermined with reference to the height of the positioning pin. A method of assembling an LED print head, characterized in that the lens is set to a height of 10 mm and stopped, and then the lens is bonded to the lens holder in this stopped state. 2. The step of setting the lens to a predetermined height with reference to the height of the positioning pin, after the lens is held by the lens holding means and maintained at a constant height,
2. A step of lowering or raising a heat sink, to which the lens holder and the head substrate are attached, by a predetermined dimension by pressing the tip end of the positioning pin while keeping the lens at that height. The method for assembling the LED print head according to claim 1. 3. The lens holding means is a suction head for holding the upper surfaces of at least the central portion and the left and right end portions of the lens in the longitudinal direction by suction so as to be flush with each other. A method for assembling the LED print head described. 4. A mount holder capable of moving up and down for mounting and holding a heat sink of an LED print head, and lens mounting of a lens holder attached to the heat sink mounted and held on the mount holder. A lens holding means for detachably adsorbing and holding the lens fitted in the working groove, and for raising and lowering so that the sucked and held lens can be maintained at a constant height, and the lens holding means. Is maintained at a constant height, the tip of the positioning pin protruding toward the upper surface of the left and right ends of the heat dissipation plate is pressed from above to displace the heat dissipation plate on the stand. A device for assembling an LED print head, comprising: a pressing means for a positioning pin that lowers a predetermined fixed dimension.