JPH0680840B2 - Optical printer head - Google Patents

Description

The present invention relates to an optical printer head that uses light emitting diodes arranged in a row.

(B) Prior Art Although a conventional optical printer head is described in Japanese Patent Laid-Open No. 58-125878, a light emitting diode (14) having light emitting portions (15) (15) ... Aligned as shown in FIG. 2 is used. ) (14) were aligned. However, if this alignment state is disturbed, the scanning line (linearity) of printing is disturbed as it is, and the printing quality is degraded. However, while the optical print head for A4 has a long effective recording length of 200 to 430 mm like 214 mm, the interval (dot pinch) of the light emitting part is as short as 0.07 to 0.15 mm, so the linearity of the entire length should be monitored. No magnifying glass or pattern recognition device has been developed so far so as to keep the dot pitch of the light emitting diode connection part constant. Therefore, the light emitting diodes are aligned by placing importance on the alignment of the light emitting parts, but 100 μm ± 10 μm
The field of view of the device that can be recognized by is at most 15 mm, so waviness is likely to occur as a whole. Therefore, the above publication proposes to provide the groove (17) in the light emitting diode mounting portion. However, it is difficult to maintain linearity by a mechanical method to form a long groove having a width of 1 to 2 mm which is substantially equal to the width of the light emitting diode, and it is difficult to flatten the bottom surface by etching or the like. Inconveniences such as tilting of the surface of the light emitting diode are likely to occur, and precision processing to solve this inconvenience would be extremely expensive, which is not preferable.

(C) Problems to be Solved by the Invention The present invention has been made in consideration of the above points, and provides an optical printer head in which a reference line within the field of view of a magnifying glass or a recognition device is provided at a relatively low cost. Is.

D) Means for Solving the Problems The present invention was made by paying attention to the accuracy of thick film printing, and has a thickness of 10 μm in the conductive pattern on which the light emitting diode is mounted.
It is formed so as to include the following printing layers, and the edges of the printing layers are used as reference lines.

(E) Action As a result, when the placement device is used to align the intervals (dot pitches) of the light emitting parts, the reference line can be simultaneously recognized in the outer contour of the placement part or in the vicinity thereof, and the placement can be performed with good linearity. The reference line can be easily obtained by thick film printing.

F) Embodiment FIG. 1 is a perspective view (a) and a sectional view (b) of an optical printer head according to an embodiment of the present invention. (1) is a substrate made of ceramic or the like and a conductive pattern for mounting a light emitting diode on the surface. (2)
And wiring patterns (3) (3).
Numerals (4), (4), ... Are light emitting diodes aligned and mounted and fixed on the conductive pattern (2) for mounting. The PN junction (5) 'is formed by selective diffusion, and the aligned light emitting portions are formed. (5) (5) ... are provided. (6) (6) ... are thin metal wires for wiring the light emitting parts (5) (5). Connection is made by a wire bond method or the like.

Since the mounting conductive pattern (2) is devised to increase the current capacity and reduce the resistance, it is printed to a thickness of 20 to 35 μm when gold paste or the like is used. Therefore, in the present invention, this is divided into a plurality of thick film printing layers (2a) (2b) (2c) and subjected to multiple printing, and at least one of them is 10 μm.
The length is set to m or less and the long side edge is printed with good linearity.
When screen printing, thick film printing layers (2a) (2b)
If the thickness of (2c) is thick, the mold is likely to lose its shape. The linearity can be improved by thinning the thickness of the printing layer, but it is not preferable to prevent the original necessity of the conductive pattern from increasing the current capacity and reducing the resistance. Further, it is not preferable to use thin film printing or deposition for the recognition means because special conditions such as a reference light source are not added. Therefore, the thickness of the printing layer is set to 10 μm or less in order to prevent the mold from being deformed more than the unavoidable value (for example, 200 μm) due to the restriction of the mesh screen plate. And a plurality of thick film printing layers (2a) stacked
In (2b) and (2c), the bottom layer (2c) is thick so that the long side edge of the bottom layer (2c) with the widest line width becomes the mounting reference line of the light emitting diode (4). It is more preferable that the thickness is 0.3 μm to 5 μm.

As a concrete example, as the bottom layer of the conductive pattern (2) of the optical printer head for A4 plate (the light emitting diodes (4) (4) ... Width 1 mm, length 8 mm, light emitting part dot pitch 100 μm),
Gold (Au) with a thickness of 3 μm over a length of 1.8 mm and 240 mm
Conductive paste was printed using as a conductive substance and low melting point glass as a binder. The linearity after dry firing is
It was within +80 μm-5 μm.

G) Effect of the Invention As described above, the present invention prevents the disconnection of the layer by providing the thickness of the lowermost layer having the widest line width among the plurality of thick film printing layers to 0.3 μm or more, and By providing a relatively small thickness of 5 μm or less, this layer does not lose its shape. Therefore, since the long side edge of this layer has a correct linearity, this edge can be used as the mounting reference line of the light emitting diode. Therefore, the light emitting diode can be easily placed on a straight line. Therefore, since the light emitting diode can be easily placed on the straight line, an optical printer head with high printing quality can be obtained. Further, since the conductive pattern is formed by laminating a plurality of thick film printed layers, the total thickness of the conductive pattern can be made large (for example, 20 to 35 μm), which results in large current capacity and low resistance. can get. Further, since each thick film printing layer can be provided relatively thinly, the surface can be formed flat, so that the light emitting diode can be placed on the thick film printing layer without tilting.

[Brief description of drawings]

FIG. 1 is a perspective view (a) and a sectional view (b) of an optical printer head according to an embodiment of the present invention, and FIG. 2 is a perspective view of a main part of a conventional optical printer head. (1) ... substrate, (2) ... conductive pattern (for mounting),
(2a) (2b) (2c) ... Thick film printed layer, (3) (3) ... Pattern, (4) (4) ... Light emitting diode, (5) (5) ...
Light emitting part, (5) '... PN junction, (6) (6) ... Metal thin wire.

Claims (1)

[Claims] 1. A substrate, a conductive pattern provided on the substrate, and a plurality of light emitting diodes aligned and mounted on the conductive pattern. The conductive pattern is formed by laminating a plurality of thick film printing layers. In addition, the bottom layer is formed to have a thickness of 0.3 to 5 μm so that the long side edge of the bottom layer having the widest line width in the thick film printing layer serves as a mounting reference line for the light emitting diode. An optical printer head that is characterized by