JPS615243A - Imaging head of optical switch array type - Google Patents

Abstract

PURPOSE:To use effectively the light of a lamp by ventilating a lamp holder of an imaging head, which is provided with the light source lamp holder and an optical switch array, independently of the optical switch array to cool effectively the lamp holder. CONSTITUTION:A lamp house 4 where a light source lamp 5 is stored is provided independently of the storage part of an optical switch array consisting of a liquid crystal. The lamp 5 is stored in a lamp storage vessel 18 of the light source lamp house 4, and its inside face 20 is subjected to specular surface treatment, and scattered light is converged and is irradiated on the optical switch array 6 through a lens 21, and the light transmitted through the array 6 by a control signal omitted in the figure passes a lens 7 and forms an image. Cooling folds 32 are provided on the outside of the lamp storage vessel 18. Fans 24 and 25 are provided in the entrance and the exit of the lamp house 4 to flow the cooling air in the direction of an arrow. Thus, the light of the light source lamp 5 is used effectively, and the liquid crystal array is protected from high temperatures.

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to an optical switch array type printer, and in particular,
The present invention relates to an optical switch array type printing head in which temperature rise due to a light source lamp is a problem.

[Background of the invention]

Recently, research has been focused on small-sized electrophotographic printers that use a printing head that is an optical signal generator consisting of an optical switch array and a light source lamp.

FIG. 5 shows its principle configuration and provides an overview of its operation.

An electrophotographic printer has a photoreceptor drum, 1 degree charger, and 2. Optical switch array type printing head main, latent image developing device 1, transfer device 11 to recording paper 10. Fixing device 12. The cleaning section 13 includes a brush 14 for removing residual toner and a discharge lamp 15 for erasing residual charges on the photoreceptor drum 1. A charger 2 is placed on the surface of the photoreceptor drum 1 in advance.
uniformly charged by corona discharge.

The optical switch array type printing head receives input information from the outside, modulates it into an optical signal, and irradiates the surface of the photoreceptor drum l with light. A latent image is formed when the surface charge on the area hit by the light disappears.

Toner 9 is once attached thereto by a developing device and visualized, and then transferred to a recording paper 10 by a transfer device 11, and further fixed by a fixing device 12 to form a permanent image.

By the way, the main optical switch array type printing head used here includes a light source 5 as shown in FIG.
an optical switch array 6 having a shutter with a thin capacitive electrode;
It also includes a first condenser lens 7 for focusing the light. 16 is a light source lamp lighting device; 17
is an optical switch array drive circuit. When the light from the light source lamp 5 reaches the surface of the optical switch array 6, the light is transmitted here only by a shutter selected according to an external signal. Then, the light is imaged and irradiated onto the surface of the photoreceptor drum 1 by the first condensing lens 7 such as a SELFOC lens.

By the way, the light source 5 of the optical switch array type printing head uses a relatively easily available fluorescent lamp, but when it is confined in the sealed light source lamp house 4, the surface temperature of the light source lamp 5 is 70 to 90°C. heated to a high temperature of ℃. Further, the fluorescent lamp itself becomes high in temperature, which is not preferable from the viewpoint of light emitting characteristics and deterioration. Conventionally, air is forcibly blown into the light source lamp house 4 for cooling, but since the gas 30 heated by the light source lamp 5 comes into direct contact with the light switch array 6,
The temperature of the optical switch array 6 ends up being heated to 40°C to 50°C. On the other hand, in order to utilize the light intensity of the light source lamp 5 as much as possible, it is better to provide the optical switch array 6 close to the light source lamp 5, but this will increase the temperature. When a liquid crystal optical switch array is used as the optical switch array 5, the temperature dependence of the physical properties of the liquid crystal becomes a problem. In particular, there is concern about the impact on response speed and contrast.

When using a ferroelectric liquid crystal with large temperature dependence, the seventh
As shown in the figure, this tendency becomes noticeable.

Here, the ferroelectric liquid crystal temperature range is 0 to 50°C.

Therefore, it is necessary to improve the method of cooling the light source lamp 5.

Note that related devices of this type include, for example, Japanese Patent Application Laid-Open No. 58-78'181. This technology is.

It is a printing head that characteristically uses a dual-frequency driven liquid crystal element, and the liquid crystal element and the light source lamp are arranged in parallel in the light source lamp house. As a result, although the negative effects of temperature rise have been pointed out, they are simply countered by cooling through air circulation inside and outside the house, and the temperature control of liquid crystal elements is difficult.

[Purpose of the invention]

An object of the present invention is to provide an optical switch array type printing head having a light source lamp house with excellent cooling efficiency, which can also be applied to an optical switch array using a liquid crystal material whose optical shutter performance has a relatively large temperature dependence. It is in.

[Summary of the invention]

As shown in FIG. 8, in the present invention, a light source lamp (for example, a fluorescent lamp) 5 is housed in a container (for example, a glass tube) 18, and a gas (for example, air) 26 flows through a tube surface 27 to cool the light source. By separating the passage 28 for cooling the optical switch array element 6 from the passage 29 for the gas 31 that cools the optical switch array element 6, the heated gas 30 is prevented from coming into direct contact with the element. As a result, as shown in FIG.
To obtain a suitable function of an optical switch array without temperature rise due to the influence of heat.

[Embodiments of the invention]

Hereinafter, the structure of a liquid crystal optical switch array type printing head 3 according to an embodiment of the present invention will be described with reference to FIGS. 1 and 2. A portion housing the light source lamp 5 is called a light source lamp house 4, and is provided independently from the storage portion of the liquid crystal switch array 6. This is because in order to reduce the influence of heat exerted by the light source lamp 5 on the liquid crystal switch array 6, the six light source lamps 5 of this embodiment, which are provided independently from the liquid crystal switch array 6, are equipped with a 30W fluorescent lamp with a peak emission wavelength of 525 nm. A light lamp was used. The light source lamp 5 is stored inside the light source lamp storage container (2) in the light source lamp house 4. This light source lamp storage container ■ not only holds the light source lamp 5, but also has a mirror finish 20 applied to its inner surface so that the scattered light emitted from the light source lamp 5 is reflected and focused on the inner surface. It also works. Furthermore, the light source lamp 5
Because of the heat generated, the temperature inside the light source lamp house 4 rises excessively, so forced air cooling is performed to suppress this. At this time, it is necessary to obtain a good flow of air.

When the cylindrical lamp storage container ■ is made of glass as in this example, the inner surface has a smooth finish to reduce surface friction resistance, so the flow of air, which is a medium for heat transfer, is It's smooth and very convenient. Note that a heat dissipation extension 32 may be provided on the outer surface of the light source lamp storage container 18. An air blowing port 22 is provided on one side of the light source lamp house 4, and an air outlet 23 is provided on the other side, and air cooling is performed in a split manner by small fans 24 and 25 that are integrally provided in each side.

Here, the structure of the lamp containment vessel 18 will be explained in more detail. The inner diameter of the lamp storage container 18 is slightly larger than the diameter of the light source lamp 5, and when the gap between the lamp storage container 18 and the light source lamp 5 is about 3 to 5 cm, air flow is particularly good and sufficient. A cooling effect can be obtained. In addition, in order to reflect and condense the light from the light source lamp 5 on the inner surface of the lamp storage container 18, a mirror finish 20 is applied to the entire surface except for the light extraction part by vapor deposition of aluminum to create a good reflective surface. In addition, the light emitted from the light source lamp 5 can be condensed without waste, and the light can be aligned in a certain direction. A slit with a width of about 5 m is provided at the exit of the focused light, and a second condensing lens 21 is integrally provided.

This allows even more effective light collection. These means apparently provide the same effect as using a light source lamp 5 with a large output capacity. The light thus obtained is extracted from the light source lamp house 4 and reaches the shutter surface of the liquid crystal switch array 6 arranged at the focal point of the second condenser lens 21. Here, an external information signal output from a terminal such as a computer is received and applied to the shutter electrode, and by selectively opening and closing the optical shutter, the output light therefrom becomes an image signal.

<Example ■> Regarding another example of the light source lamp storage container in the optical switch array printing head, an example in which the light source lamp storage container unit and the second condensing lens 21 are manufactured by integral processing is shown in the third example. This will be explained using figures. Using a transparent glass member or plastic member, two circles are deeply overlapped and connected to form a container 1B whose outer periphery is approximately daruma-shaped. A concentric hollow hole 28 is provided in one of the circular portions 19, and the inner diameter of the hollow hole 28 is made larger than the diameter of the light source fluorescent lamp 5. The light source lamp 5 is housed inside the cavity hole 28, and a cooling air passage is formed in the gap. In other words, the container 18 is a light source lamp storage container that has a circular hollow part in which the light source lamp 5 can be stored, and a part corresponding to the second condensing lens 21 that has a crescent-shaped convex lens shape. 18 is obtained. Furthermore, on the inner surface of the part where the light source lamp 5 is stored,
The entire surface except for the light extraction portion is subjected to a mirror finish 20, for example, by vapor deposition of aluminum. As a result, the light from the light source lamp 5 is reflected and further condensed by the second condensing lens 21, so that the light can be efficiently extracted to the outside of the light source lamp house 4.

Therefore, it is possible to realize a light source lamp storage container that is easy to process without impairing the functions of the light source lamp storage container.

<Example ■> Another example will be described with reference to the cross-sectional view of FIG. 4. In this embodiment, the side 1 forming the light reflecting surface of the light source lamp storage container 1B is
9 is made into a parabola.

The inner surface is subjected to two full mirror finishings, and second condensing lenses 21 are integrally provided on both sides. Furthermore, the focal position fl of the mirror surface! By arranging the center of the light source lamp 5 at 33, the irradiated light from the light source lamp 5 becomes a parallel light beam directed at right angles to the optical axis of the second condenser lens 21, and is focused by the second condenser lens 21. It is taken out.

Therefore, it is possible to obtain a light source lamp container that is easy to process without impairing the cooling function of the light source lamp container according to the present invention and the function of effectively utilizing the light from the light source lamp.

〔Effect of the invention〕

According to the present invention, the light from the light source lamp can be effectively utilized by providing an effective cooling effect and giving the light source lamp storage container a lens effect or a mirror effect.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a printing head equipped with a light source lamp storage container of the present invention, FIG. 2 is a cross-sectional view of the printing head shown in FIG. 1, and FIGS. 3 and 4 are a light source of the present invention. A cross-sectional view of the printing head of another embodiment of the lamp storage container, Fig. 5 is a JM construction diagram of a conventional printer, Fig. 6 is a configuration diagram of the printing head in a conventional printer, and Fig. 7 is a diagram of the printing head of the conventional printer. An explanatory diagram of the temperature dependence of the ferroelectric liquid crystal used in the embodiment of the invention, FIG. 8 is an explanatory diagram of the light source lamp storage container according to the invention, and FIG. 9 is an illustration of the effect of the light source lamp storage container according to the invention. FIG. 1 β-... Optical switch array type printing head, 4...
Light source lamp house, 5... Light source lamp, 6... Light switch array, 7... First condensing lens, 18-...
Light source lamp storage capacity, 20...Mirror finish, 21...
Second condensing lens, 24. 25... Fan for blowing/discharging air, 26... Gas (air), 32... Cooling panel for the outer surface of the light source lamp storage container.

Claims (1)

[Claims] 1. A light source lamp, a light source lamp house that houses this light source lamp, an optical switch array consisting of a plurality of optical shutters that control the amount of light transmission by applying a voltage or a magnetic field, and this optical switch array. In the optical switch array type printing head, the light source lamp house includes a light source lamp storage container storing the light source lamp, and a light source lamp storage case in which the light source lamp is stored. 1. An optical switch array printing head comprising a fan that blows air into the container and the optical switch array section for cooling. 2. The optical switch array type printing head according to claim 1, further comprising a fan for discharging cool air at the outlet of the light source lamp house. 3. The optical switch array type printing head according to claim 1, wherein the optical switch array is an element using ferroelectric liquid crystal. 4. The optical switch array type printing head according to claim 1, wherein the front optical switch array is a thin film magnetic garnet element. 5. The optical switch array type printing head according to claim 1, wherein the gas sent into the light source lamp storage container is air. 6. The optical switch array type printing system according to claim 1, further comprising means for changing the temperature of the gas sent into the light source lamp storage container according to the temperature of the optical switch array. head. 7. The optical switch array type printing according to claim 1, wherein an opening of the light source lamp storage container that serves as a light output portion from the light source to the optical switch array is made of a transparent member. head. 8. Claim 1, characterized in that the inner surface of the light source lamp storage container is mirror-finished so that the light from the light source lamp can be focused to effectively utilize the light from the light source. The optical switch array type printing head described. 9. The optical switch array type printing head according to claim 1, wherein the cross-sectional shape of the light source lamp storage container is circular or parabolic. 10. The optical switch array type printing head according to claim 1, wherein a condensing lens for converging light is integrally attached to the light exit portion of the light source lamp storage container. 11. The optical switch array type printing head according to claim 1, wherein the member of the light source lamp storage container is made of a glass material, a plastic material, or a metal member. 12. The optical switch array type printing head according to claim 1, characterized in that the outer surface of the light source lamp storage container is provided with folds.