JPH034528Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Technical Field) The present invention relates to an assembly structure of an optical print head used in a photo printer.

(Prior Art) In recent years, photo printers using light emitting diode (LED) arrays as light sources have been developed and their results have been published in various literature. For example, pages 1 to 93 of "Research and Practical Application Report VOL.31 No. 3" published by the Telecommunications Research Institute of Nippon Telegraph and Telephone Public Corporation, or pages 114 to 93 of "Nikkei Electronics 1981 5-25"
There is a detailed explanation of this type of technology on page 128.

FIG. 1 is a structural diagram of an optical print head used in a conventional photo printer of this type.
Illustrated with a partial cutaway. In the figure, 1a ₁ , 1
a ₂ ,..., 1b ₁ , 1b ₂ ,... are a large number of elements, in other words, light emitting diodes arranged horizontally in a straight line, for example, 100 μm.
It is an integrated LED array arranged at intervals of
2a and 2b are focusing fiber lens arrays (hereinafter simply referred to as lens arrays). 3a, 3
b is a base, which is used in pairs, and is used for the LED arrays 1a ₁ , 1a ₂ , . . . , 1b ₁ , 1b ₂ , respectively.
... are fixed in a staggered manner along the width direction of a photosensitive drum (not shown) to ensure the print width, and the light emitted from the LED array arranged in the staggered manner is transmitted through the lens arrays 2a and 2b, which will be described later. (FIG. 2) The photosensitive drum is set at an angle so that the image is formed on a straight line with continuity on the photosensitive drum, which is the recording surface. Also, 4a ₁ , 4a ₂ , ... are drive ICs for emitting light from the corresponding LED arrays 1a ₁ , 1a ₂ , ...
and 5a ₁ , 5a ₂ , ..., 5b ₁ , 5b ₂ ... are the above-mentioned
This is a cable that connects the LED array and the drive IC in units of light emitting dots, and 6 is the drive IC 4a ₁ ,
This bus cable is on the input side of 4a ₂ , . . . and connects them in multiple ways.

FIG. 2 is a diagram illustrating the path of light that forms the main part of the optical print head shown in FIG. 1. In the figure, 1a ₁ and 1b ₁ are LED arrays, 2a,
2b is a lens array, and 7 is a photosensitive drum for recording an image emitted from the LED array. Further, 7C is an image forming area obtained on the photosensitive drum 7,
The erect, same-size image of the light emitting part of the LED array is drawn and stored as a straight line dot row as dot subtraction information. In this imaging section 7C, it is desirable that the information is focused on a line, and for this reason, it is necessary that the working distances l ₁ and l ₂ of the lens array be at equal intervals, and furthermore, it is necessary that the working distances l 1 and l 2 of the lens array In order to obtain linear optical information without any color, multiple LED arrays 1a ₁ , 1a ₂ , ..., 1b ₁ , 1 are arranged in a staggered manner to ensure the printing width.
It is necessary to assemble the light emitting lines obtained from each of b ₂ , .

Now, looking at the assembly structure of the optical print head described above, it can be seen that there is a problem in its manufacturability. That is, LED arrays 1a ₁ , 1a ₂ ,
..., 1b ₁ , 1b ₂ ..., drive ICs 4a ₁ , 4a ₂ , ... and cable 5 are integrated into the base 3.
A plurality of bases 2a, 2b must be installed to satisfy the required printing width, and furthermore, bases 2a, 2
b gives an angle so that each light path is converged on the photosensitive drum 7. Therefore, in order to adjust the working distances l ₁ and l ₂ of the lens arrays 2a and 2b,
The positions of the optical axis directions Y ₁ and Y ₂ and X ₁ and X ₂ must be adjusted until the imaging section 7C focuses them as a dot. Due to these factors, in assembling a conventional optical print head, it takes a large number of man-hours to assemble two rows of optical axis systems without errors due to the number of component parts and the processing accuracy required for them. is clear.

The operation of a photo printer using the optical print head having the above-mentioned configuration has been explained in detail in the above-mentioned literature, and will not be explained here.

(Purpose and structure of the invention) The present invention was made to eliminate the above-mentioned problems, and in this type of print head, a large number of LED arrays are arranged on one base board. The assembly structure of an optical print head is obtained by assembling an LED array unit consisting of an LED array unit, a cover having a lens array attached to the unit at a position facing the LED array, and a side plate that integrates the unit and the cover. By doing so, it is possible to obtain a simple configuration and assembly of the LED array unit and optical system. below,
The present invention will be explained in detail using figures.

(Description of Embodiments) FIG. 3 is a partially sectional perspective view showing an embodiment of the optical print head assembly structure according to the present invention. In the figure, 11 is integrated in a straight line in the center.
The LED array unit is made up of an array of LED arrays 12. Reference numeral 13 is a base on which the LED array unit 12 is firmly mounted, and includes a heat dissipation fin portion 14 and a shoulder portion 1 for efficiently dissipating heat from the unit.
5, 15' and leg parts 16, 16'. 1
Reference numeral 7 denotes a lens array arranged in a straight line facing the LED array 12 to form an image emitted from the LED array 12 on the photosensitive surface of a photosensitive drum (not shown); 18 a cover for mounting and holding the lens array 17; , 19 are U-shaped side plates made of a thin material with spring properties such as non-magnetic spring stainless steel.

4 and 5 are a longitudinal cross-sectional view and a cross-sectional view showing the shape of the cover 18, respectively, showing the base 13, the LED array 12, and the lens array 1.
It shows the relationship with 7th magnitude. That is, referring to FIG. 4, reference numeral 21 is a stop portion formed on the cover 18, which is a positioning portion for the lens array 17, and the lens array 17 is positioned on the photosensitive surface of the photosensitive drum 7 via the lens array 17. In order to obtain a pair-one connection, the distance l ₃ + l ₄ between the photosensitive surface and the LED array light emitting part point G is
The lens array 17 is formed so as to be locked at a position where l ₃ =l ₄ . A hole 22 is formed at one end of the cover 18, into which a pin 23 screwed into the base 13 is inserted and positioned relative to the base 13, and a hole 24 is formed at the other end, and a pin 25 screwed into the base 13 is inserted. is inserted. At this time, hole 22
The diameter of the pin 23 is approximately equal to the outer diameter of the pin 23, so the cover 18 does not wobble, and the hole 24 at the other end is formed as a blank hole. Further, referring to FIG. 5, the cover 18 supports the legs 16, 16' of the base 13 and supports the side plate 1 as shown.
Claws 26 and 26' are formed to which 9 is engaged, and further,
In order to hold the lens array 17 and maintain straightness in the longitudinal direction, a protrusion 27 is provided and a groove 28 is formed.

Next, the assembly of the optical print head made up of the components as described above will be explained with reference to FIGS. 3, 4, and 5. First, the LED array unit 11 having the LED array 12 is
As shown in the figure, it is bonded to the bottom surface of the base 13 formed between the legs 16, 16' of the base 13 using a thermally conductive adhesive, such as an epoxy resin,
Become one. On the other hand, in the cover 18, the lens array 17 is inserted into the groove 28 formed by the protruding part 27 until it is locked by the stop part 21,
It is fixed to the stopper part 21 with an adhesive if necessary.
Next, the cover 18 formed as described above is inserted into the hole 22.
Using the holes 24 and 24, pins 23 and 25 are screwed into the base 13 in advance as shown in FIG.
and position it with respect to the base 13. In this state, the shoulders 15 and 1 formed on the base 13 are
5' and the claws 26, 2 formed on the cover 18.
6' with both ends, and attach base 1.
3 and the cover 18 are integrated and assembled.

In addition, during the above assembly, a bus cable (not shown) as shown in FIG. 1 is connected to the end of the LED array unit 11, and is further connected to the control circuit section (not shown). Since these parts are not particularly relevant to the present invention, they are not shown in the drawings and their explanations will be omitted.

FIG. 6 is an explanatory diagram showing the optical path obtained by the present invention. As described above, the lens array 17, which is held by a cover (not shown) and whose linearity is maintained, is always located on the optical axis Y of the LED array 12, so that the imaging point on the photosensitive drum 7 is 7D
is always obtained on the optical axis Y. Therefore, it is clear that in order to obtain a clear focus at the imaging point 7D, only the height of the working distance _l4 needs to be finely adjusted. This means that in the present invention, the relationship between the working distances l _{1 and l 2} described in FIG. This shows that since the structure satisfies the height h corresponding to the distance up to 21, it is necessary to adjust only the working distance _l4 .

Therefore, the position adjustment of the optical axis system becomes easy,
The overall assembly of the optical print head is also facilitated.

Next, thermal distortion during operation and non-operation of the optical print head as described above will be explained with reference to FIGS. 3 and 4.

First, when the LED array unit 11 is in operation, the internal temperature of the base 13 closest to the LED array 12 rises above the room temperature, causing thermal strain between it and the cover 18, which is not directly affected by temperature. . The base 13 mainly expands in the longitudinal direction, that is, in the fourth direction due to its unique coefficient of linear expansion as the temperature rises.
It will extend in the W direction in the figure.

According to this embodiment, since the longitudinal positioning is performed by the pin 23 and the hole 22, the thermal strain in the direction W in FIG. Even if directional distortion occurs, the engagement between the cover 18 and the base 13 is maintained by the spring properties of the side plates 19.

In the embodiment described above, the positioning of the cover 18 using the holes 22, 24 and the pins 23, 25,
Furthermore, the base 13 and the cover 18 were integrated with the U-shaped side plate 19 by using the shoulders 15, 15' and the claws 26, 26' formed respectively, but these could be realized using other structures. There is no need to explain what you can do.

(Effects of the invention) As described above in detail, according to the invention, the LED array unit 11, which is indispensable to the configuration of the optical print head, is integrated into the base 13, which has a structure that takes heat radiation into consideration. Furthermore, the optical system including the lens array 17 etc. is fixed to the base 13 in consideration of thermal distortion of the base 13. To explain, even if there is thermal expansion of the base 13 due to the LED array 12, it is covered. Since the hole 24 formed in 18 is a blank hole, the distortion is absorbed and does not affect the optical system.Furthermore, it is easy to adjust the image formation, and has good manufacturability, and can be used as a mass-produced product. Excellent effects such as making it possible to realize a small and low-cost optical print head can be expected.

[Brief explanation of the drawing]

Fig. 1 is a structural diagram of a conventional optical print head, Fig. 2 is a diagram explaining the path of light obtained from its main parts, and Fig. 3 is an example of the assembly structure of an optical print head according to the present invention. Partial cross-sectional perspective view shown, No. 4
FIG. 5 is a vertical sectional view and a cross sectional view of the cover constituting the main part of FIG. 3, respectively, and FIG. 6 is a diagram illustrating the path of light obtained by the present invention. 1a ₁ , 1a ₂ ..., 1b ₁ , 1b ₂ ... are LED arrays, 2
a and 2b are lens arrays, 3a and 3b are bases,
4a ₁ , 4a ₂ , ... are drive ICs, 5a ₁ , 5a ₂ , ...,
5b ₁ , 5b ₂ , ... are cables, 6 is bus cable,
7 is a photosensitive drum, 11 is an LED array unit,
13 is a base, 14 is a heat radiation fin part, 15, 1
5' is a shoulder part, 16, 16' are leg parts, 17 is a lens array, 18 is a cover, 19 is a side plate, 21 is a stop part, 22, 24 are holes, 23, 25 are pins, 26,
26' is a claw, 27 is a protrusion, and 28 is a groove.

Claims (1)

[Scope of utility model registration request] It consists of an LED array and a focusing optical fiber lens array arranged along the axial direction of the photosensitive drum.
The assembly structure of an optical print head that forms an image from an LED array in a straight line on the photosensitive drum via the lens array includes an LED array unit in which the LED array is disposed on a base substrate, and the unit in the bottom thereof. a base that is attached to the unit and forms heat dissipation fins for dissipating heat from the unit and a protruding shoulder;
At the time of assembly, the focusing optical fiber lens array is attached to a position facing the LED array while maintaining its straightness, and a cover having a protruding claw portion is attached, and a base on which the cover and the LED array unit are attached is attached with a spring-like structure. 1. An assembly structure for an optical print head, characterized in that the shoulder portion and the claw portion are integrally constructed by sandwiching the shoulder portion and the claw portion with a side plate having a side plate.