JPH0664226A - Optical printer head - Google Patents

Abstract

(57) [Abstract] [Purpose] An optical printer head capable of preventing light from leaking from the side surface of each light emitting diode element, having a high emission brightness, and having a clear emission contour to obtain high quality printing and printing. To provide. A plurality of light emitting diode elements 4 having a pair of electrodes are linearly arranged and mounted on an insulating substrate 1 having a common wiring conductor 2 and a plurality of individual wiring conductors 3, and one of the light emitting diode elements 4 is mounted. Electrode of common wiring conductor 2
In common with the above, in the optical printer head in which the other electrode is individually connected to each individual wiring conductor 3, the reflection film 5 is attached to the side surface of the light emitting diode element 4.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement of an optical printer head used as a light source of a recording device such as an electrophotographic printer.

[0002]

2. Description of the Related Art Recently, with the progress of information processing technology and communication technology, a compact and inexpensive electrophotographic printer capable of outputting a large amount of arbitrary kanji and figures on plain paper at high speed and high quality. Is required. Therefore, in order to meet this demand, an electrophotographic printer using an optical printer head, in which a plurality of light emitting diode elements (LEDs) are linearly mounted on one main surface of an insulating substrate as a light source of a printer, is small and high. It is proposed as a resolution one.

As shown in FIGS. 3 and 4, the optical printer head used in this conventional electrophotographic printer usually has a common wiring conductor 12 made of a metal material such as aluminum, nickel, or gold on the upper surface and individual wiring conductors. A base body made of an electrically insulating material such as ceramic or glass on which the wiring conductor 13 is formed.
A plurality of light emitting diode elements 14 having a pair of electrodes are linearly arranged and mounted on 11, and both electrodes of each light emitting diode element 14 are connected to a common wiring conductor 12 and individual wiring conductors 13.
It has a structure electrically connected to the common wiring conductor 12
Also, electric power is applied to each light emitting diode element 14 through the individual wiring conductor 13 to selectively emit light from the upper surface of each light emitting diode element 14, thereby functioning as a light source for an electrophotographic printer or the like.

In the optical printer head, light emitting diode elements linearly arranged and mounted on the insulating substrate 11
14 is, for example, made of gallium-arsenic-phosphorus (GaAsP),
The light emitting diode element 14 usually constitutes one light emitting diode array 14a with 64 of them as a unit. When the light emitting diode array 14a is used as a light source of a B4 size electrophotographic printer, the light emitting diode array 14a has 32 of the light emitting diode arrays 14a. They are arranged linearly on the insulating base 11.

[0005]

However, in this conventional optical printer head, the light emitting diode element 14 is used.
The main light emitting portion of the light emitting diode element 14 is the upper surface portion, but light equivalent to about 30% of the main light emitting portion leaks from the side surface, and the insulating substrate 11 is made of glass, ceramics, etc. Since the conductors are made of aluminum, nickel, gold, etc. and all of them are materials that easily reflect light, light is emitted by applying predetermined power to the light emitting diode element 14 via the common wiring conductor 12 and the individual wiring conductor 13. In this case, the light leaked from the side surface of the light emitting diode element 14 is reflected by the upper surface of the insulating substrate 11 and the common wiring conductor 12, and this is combined with the main light emission of the light emitting diode element 14 to make the light emitting contour of the light emitting diode element 14 unclear. It had a clear drawback. Therefore, when this optical printer head is used as a light source of an electrophotographic printer, printing and printing become unclear due to the unclear emission contour of the light emitting diode element, and the printing and printing quality is greatly deteriorated. Met.

[0006]

SUMMARY OF THE INVENTION The present invention has been devised in view of the above-mentioned drawbacks, and it is an object of the present invention to prevent light from leaking from the side surface of each light emitting diode element, to provide a high emission brightness and a high emission contour. An object of the present invention is to provide an optical printer head that can obtain high quality printing and printing.

[0007]

According to the present invention, a plurality of light emitting diode elements having a pair of electrodes are linearly arranged and mounted on an insulating substrate having a common wiring conductor and a plurality of individual wiring conductors, and each of the above-mentioned light emitting elements is mounted. In an optical printer head in which one electrode of a diode element is commonly connected to a common wiring conductor and the other electrode is individually connected to each individual wiring conductor, a reflection film is attached to a side surface of the light emitting diode element. It is a feature.

[0008]

According to the optical printer head of the present invention, the side surface of the light emitting diode element mounted on the insulating substrate is coated with a reflective film to effectively prevent light from leaking from the side surface of the light emitting diode element. Since the light leaking from the side surface of the light emitting diode element is returned to the main light emitting part side, the light emission of the light emitting diode element becomes a high brightness of the main light emitting part and the emission contour is clear, and as a result, the electrophotography When it is used as a light source of a printer, an extremely clear latent image that enables high-quality printing and printing can be formed on the photoconductor of the printer.

[0009]

The present invention will now be described in detail with reference to the accompanying drawings. 1 and 2 show one embodiment of the optical printer head of the present invention, 1 is an insulating substrate, 2 is a common wiring conductor, 3 is an individual wiring conductor, 4 is a light emitting diode element, and 5 is a reflective film.

The insulating substrate 1 is made of an electrically insulating material such as alumina ceramics or glass, and the light emitting diode 4 is mounted on the upper surface of the insulating substrate 1 to fix and support the light emitting diode element 4.

When the insulating base 1 is made of alumina ceramics, for example, alumina (Al ₂ O ₃ ) and silica (Si
O _2), calcia (CaO), which adopt a well-known doctor blade method or calendar roll method also the magnesia (MgO) material powder in a suitable organic solvent such as the solvents were admixed makes with mud漿状Thus, a ceramic green sheet (ceramic green sheet) is obtained, and thereafter, the ceramic green sheet is punched into a predetermined shape and fired at a high temperature (about 1600 ° C.).

A strip-shaped common wiring conductor 2 and a plurality of individual wiring conductors 3 are adhered and formed on the upper surface of the insulating substrate 1. The common wiring conductor 2 and the individual wiring conductors 3 are attached to the light emitting diode element 4. It has a function of supplying a predetermined electric power required for light emission.

The common wiring conductor 2 and the individual wiring conductor 3 are made of a metal material such as aluminum, nickel and gold. For example, aluminum (Al) is formed on the insulating substrate 1 by a thin film forming technique such as a vapor deposition method or a sputtering method. 1.0 to 3.0
It is formed by depositing it to a thickness of μm and forming it into a predetermined pattern by a photolithography technique, and then sequentially depositing nickel and gold on this aluminum pattern by an electrolytic plating method or an electroless plating method.

When depositing an aluminum pattern on the insulating substrate 1, a layer of titanium (Ti), chromium (Cr) or the like is formed between the insulating substrate 1 and the aluminum pattern by 100.
If it is applied to a thickness of ~ 1000 angstrom, the bonding strength between them can be made extremely strong. Therefore, there is a thickness between the insulating substrate 1 and the aluminum pattern.
100-1000 Angstroms of titanium (Ti) and chrome (Cr)
It is preferable to provide a layer composed of

Further, a plurality of light emitting diode elements 4 having a pair of electrodes are linearly arranged and mounted on a part of the upper surface of the common wiring conductor 2. One electrode of each light emitting diode element 4 is a common wiring conductor. The other electrode is also electrically connected to each individual wiring conductor 3 via a bonding wire 6.

When a predetermined power is applied from the common wiring conductor 2 and the individual wiring conductors 3, the plurality of light emitting diode elements (LEDs) 4 emit light having a brightness of, for example, 8 microwatt steradian, and the light is emitted. A latent image for forming an image is formed on the photoconductor by irradiating the photoconductor surface of the electrophotographic printer with light.

The light emitting diode element 4 is a GaAsP type, Ga
P-based light-emitting diodes are used.For example, in the case of GaAsP-based light-emitting diodes, the GaAs substrate is first heated to a high temperature in a furnace and AsH ₃ (arsine), PH ₃ (phosphine), Ga (gallium) are used. ) Is brought into contact with the substrate to grow an n-type semiconductor GaAsP (gallium-arsenic-phosphorus) single crystal on the substrate surface, and then a Si ₃ N ₄ (silicon nitride) windowed film is formed on the GaAsP single crystal surface. It is attached and Zn (
It is formed by exposing a (zinc) gas to diffuse Zn into a part of the GaAsP single crystal of the n-type semiconductor to form a p-type semiconductor and having a pn junction.

In the case of the B4 optical printer head, 2048 (8 per 1 mm) light emitting diode elements 4 are linearly arranged. Specifically, 64 light emitting diode elements are set as one unit. By arranging 32 light emitting diode arrays 4a linearly, 2048 light emitting diode elements 4 are arranged on the insulating base 1.

Further, each of the light emitting diode elements 4 is coated with a reflection film 5 on its side surface, and the reflection film 5 effectively prevents the light from leaking from the side surface of the light emitting diode element 4 and leaks it from the side surface. The light you are trying to
It has a function of returning to the main light emitting side.

The light emitting diode element 4 is coated with a reflection film 5 on its side surface, and the light which is about to leak from the side surface of the light emitting diode element 4 is returned to the main light emitting portion side by the reflection film 5. Therefore, when a predetermined power is applied to the light emitting diode element 4 through the common wiring conductor 2 and the individual wiring conductor 3 to emit light, the emission brightness of the main light emission of the light emitting diode element 4 is improved by about 10%, and as a result, electrophotography When it is used as a light source of a printer, an extremely clear latent image that enables high-quality printing and printing can be formed on the photoconductor of the printer.

Further, the light emitting diode element 4 is coated with a reflection film 5 on its side surface to prevent light from leaking from the side surface of the light emitting diode element 4, so that when the light emitting diode element 4 is made to emit light, The main light emission of the element 4 and the light leaking from the side face are never combined to make the contour unclear, and as a result, when used as a light source of an electrophotographic printer, the contour is clear on the photoconductor of the printer. It is possible to form a latent image.

The reflective film 5 is made of a material having a high reflectance such as silver. When the reflective film 5 is made of silver, for example, a silver paste obtained by adding and mixing an appropriate organic solvent or solvent to silver powder is used as a light emitting diode element. 4 is applied to the side surface of the light emitting diode element 4 by a thick film method and is baked at a temperature of 80 to 150 ° C.

If the thickness of the reflective film 5 is less than 0.5 μm, it is difficult to completely prevent light from leaking from the side surface of the light emitting diode element 4, and the light emitting contour of the light emitting diode element 4 becomes unclear. There is a risk of clarity.
Therefore, the thickness of the reflective film 5 is preferably 0.5 μm or more.

Thus, according to the optical printer head of the present invention, predetermined power is selectively applied to each light emitting diode element 4 linearly arranged and mounted on the insulating substrate 1 through the common wiring conductor 2 and the individual wiring conductor 3. And each light emitting diode element 4
To function as a light source of an electrophotographic printer.

The present invention is not limited to the above-mentioned embodiments, but various modifications can be made without departing from the scope of the present invention. For example, the reflection film 5 is limited to silver. Rather, any material such as gold or solder can be used as long as it is a material that effectively prevents light from leaking from the side surface of the light emitting diode element 4 and returns the light that is about to leak from the side surface to the main light emitting surface side. May be.

[0026]

According to the optical printer head of the present invention, the side surface of the light emitting diode element mounted on the insulating substrate is coated with a reflection film to prevent light from leaking from the side surface of the light emitting diode element. Since the light leaking from the side surface of the light emitting diode element is returned to the main light emitting surface side, when a predetermined power is applied to the light emitting diode element through the common wiring conductor and the individual wiring conductor to cause light emission, The element emits only the main emission with high brightness and a clear emission contour, and as a result, when used as the light source of an electrophotographic printer, it is extremely clear that it enables high-quality printing and printing on the photoconductor of the printer. A latent image can be formed.

[Brief description of drawings]

FIG. 1 is an enlarged sectional view of an essential part showing an embodiment of an optical printer head of the present invention.

FIG. 2 is a partially enlarged plan view of the optical printer head shown in FIG.

FIG. 3 is an enlarged cross-sectional view of a main part of a conventional optical printer head.

4 is a partially enlarged plan view of the optical printer head shown in FIG.

[Explanation of symbols]

 1 ... Insulating substrate 2 ... Common wiring conductor 3 ... Individual wiring conductor 4 ... Light emitting diode element 5 ...・ Reflective film

Continuation of the front page (51) Int.Cl. ⁵ Identification number Office reference number FI technical display location H01L 33/00 N 7514-4M H04N 1/036 A 9070-5C

Claims (2)

[Claims] 1. A plurality of light emitting diode elements having a pair of electrodes are linearly arranged and mounted on an insulating substrate having a common wiring conductor and a plurality of individual wiring conductors, and one electrode of each of the light emitting diode elements is mounted. What is claimed is: 1. An optical printer head comprising a common wiring conductor, the other electrode of which is individually connected to each individual wiring conductor, wherein a reflection film is attached to a side surface of the light emitting diode element. 2. The optical printer head according to claim 1, wherein the reflective film is made of silver.