JPS63108315A - Method for controlling light quantity of bubble shutter - Google Patents

Abstract

PURPOSE:To control the quantity of light projected from a bubble shutter in steps or steplessly by changing the quantity of heat generation of a heat generating body in steps or steplessly. CONSTITUTION:The current supply, i.e. heat generation, of the heat generating body 13 is changed on the basis of a command signal from a control circuit 14. At the time of suppressing the current supply to a low level, bubbles generated in a solution 12 are small. Thereby, an optical path of incident light beams passed into the solution 12 is expanded and the quantity of projected light is reduced. In case of increasing the heat generation of the heat generating body 13, bubbles are expanded sharply in an optical path direction. Thereby, the optical path of incident light beams passed into the solution 12 is shortened and the quantity of projected light is increased. Thus, the heat generation of the heat generating body 13 is changed in steps or steplessly through the control circuit 14 to obtain the quantity of projected light increased/decreased in accordance with the change in the heat generation.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a bubble shutter used in an optical writing device of an electrophotographic printer, and particularly relates to a method for controlling the amount of light passing through the bubble shutter. It is something.

[Prior art] As this type of bubble shutter, for example, Japanese Patent Application Laid-Open No. 59-2
The one shown in Japanese Patent No. 2034 is already known. To explain this with reference to FIG. 3, an opaque liquid 2 that does not transmit light is filled in a translucent cell 1 whose light entrance wall and light exit wall are each made of a transparent material. A heating element 3 is disposed in the liquid 2, and bubbles 4 are generated in the liquid 2 by causing the heating element 3 to generate heat based on print or image input signals from a computer, etc., and the incident light is emitted through the bubbles 4. It was designed to let you do so.

This bubble shutter has the advantage of faster response speed to input signals than conventionally known optical shutters such as liquid crystal shutters.

[Problems to be Solved by the Invention] However, the bubble shutter disclosed in the above-mentioned publication merely performs binary control of passing or blocking light, so it is difficult to print or record images with gradation. Alternatively, exposure processing could not be performed.

[Object of the Invention] The present invention has been made in view of the above problems, and its purpose is to adjust the amount of light emitted by the bubble shutter in multiple stages or steplessly. An object of the present invention is to provide a method for controlling the amount of light of a bubble shutter, which enables the following. With this, it is intended to realize printing with gradation, image recording, exposure processing, etc. at high speed.

[Means for Solving the Problems] In order to achieve the above object, the light amount control method for a bubble shutter according to the present invention is such that the light entrance wall and the light exit wall are each made of a transparent material, and the light exit wall is connected from the entrance wall to the exit wall. A control circuit in which a liquid having a certain light transmittance is filled in a translucent cell having a long optical path, and a heating element disposed in the liquid is disposed outside the translucent cell. In the bubble shutter, the bubble shutter is configured to generate bubbles in the liquid by generating heat according to a command signal from the control circuit, and light passes through the bubbles to an optical path in the liquid. The size of the bubbles in the liquid (expansion amount in the optical path direction) is changed stepwise or steplessly according to a command signal of the heating element, and the size of the bubbles in the liquid (expansion amount in the optical path direction) is The gist is that the amount of light emitted is adjusted.

[Embodiment] An embodiment of the present invention will be described below with reference to FIGS. 1 to 3. The illustrated bubble shutter S is a light incident wall 11a.
and the output wall 11b are each made of a transparent material, and the light path from the input wall 11a to the output wall 11b is formed to be long. The liquid 12 is filled with a liquid 12 (the ratio of the amount of emitted light to the amount of emitted light). The liquid 12 is preferably a mixture of ink dissolved in water, but is not limited thereto. However, the light transmittance is such that when there are no bubbles in the liquid 12 in the translucent cell 11, the amount of light incident on the liquid 12 in the case 11 from the entrance wall 11a is It is desirable to select a value so that it gradually disappears as it advances, and becomes almost zero at the surface of the exit wall 11b. Thus, a heating element 13 is disposed on the inner surface of the entrance wall 11a of the translucent cell 110, and the heating element 3 is connected to a control circuit 4 disposed outside the translucent cell 11. The control circuit 14 receives the heating element 13 based on an external input signal.
A variable resistor (
(not shown) is built-in. A through hole 15 is provided in the center of the heating element 13 so that the path of light entering the translucent cell 11 from the entrance wall 11a is not blocked. Further, a flow channel 16 is provided in the upper mold 11c of the translucent cell 11, and the flow channel 16
A water reservoir (soak 17) is provided in a continuous manner, so that when bubbles B are generated in the liquid 12 in the translucent cell 11, the liquid 12 in the translucent cell 11 is transferred to the water reservoir tank. 17, and conversely, when the bubble B disappears, the spilled liquid is naturally returned to the translucent cell 11, and the liquid pressure inside the translucent cell 11 is adjusted. .

However, according to the bubble shutter configured in this way, for example, when a character or image signal from a computer is input to the control circuit 14, a current flows from the control circuit 14 to the heating element 13 according to the electric signal, heating element 1
3 is heated, and bubbles B are generated in the liquid 12. Therefore, when the character or image signal from the computer requires gradation, the energization m sent from the control circuit 14 to the heating element 13 is decreased or increased in accordance with the command signal. If this is done, for example, when the amount of electricity is kept low, the bubbles B generated in the liquid 12 will be small as shown in FIG. Therefore, in this case, the entrance wall 1
The optical path through which light enters the liquid 12 in the translucent cell 11 passes through the liquid 12 is longer than in the case 1a, and the loss of light quantity increases accordingly. Therefore, the amount of light emitted from the emission wall 11b is small. On the other hand, when the amount of heat generated by the heating element 13 is increased, the bubbles B expand greatly in the optical path direction, as shown in FIG. Therefore, in this case, the light is
The optical path passing through 2 is shorter than in the case of FIG.

Thus, by changing the amount of heat generated by the heating element 13 stepwise or steplessly via the control circuit 14, the amount of emitted light can be increased or decreased accordingly. FIG. 3 shows a state in which bubble shutters configured as described above are arranged in a row as one unit element. As shown in the figure, by controlling a certain element to generate a small bubble B and another element to generate a large bubble B according to a command signal from the control circuit 14, the amount of light emitted from each element is controlled. It can be different. Therefore, if the bubble shutter configured as described above is used as an optical shutter in, for example, an optical writing device of an electrophotographic printer, printed matter of characters or images with gradation can be obtained.

Note that if the heating element 13 in the above embodiment is made of a transparent material, such as tin oxide or indium oxide, deposited on the entrance wall 11a, there is no need to open the through hole 15 in the center of the heating element, making it easier to manufacture. can be simplified.

[Effects of the Invention] As described above with respect to the embodiments, the present invention can provide gradated printing and image display by applying it to optical printers, display displays, and the like. Furthermore, this bubble shutter has the characteristic that its response speed to electrical signals is extremely fast compared to conventional liquid crystal shutters, etc., and is extremely useful industrially.

[Brief explanation of the drawing]

Fig. 1 is a sectional view of the bubble shutter according to the present invention, Fig. 2 is a sectional view for explaining its operating state, Fig. 3 is a sectional view for explaining its specific usage state, and Fig. 4 is a sectional view for explaining its operating state. FIG. 2 is a cross-sectional view showing the operating state of a conventional bubble shutter. S...Bubble shutter, 11...Translucent cell, 11
a...Incidence wall, 11b...Output wall -12.
...Liquid, 13...Heating element, 14...Control circuit, B...Bubble.

Claims (1)

[Claims] A liquid with a certain light transmittance is filled in a translucent cell in which the light entrance wall and the light exit wall are each made of a transparent material, and the optical path from the entrance wall to the light exit wall is formed to be long. Bubbles are generated in the liquid by causing a heating element placed in the liquid to generate heat in accordance with a command signal from a control circuit placed outside the translucent cell, and light passes through the bubbles into the liquid. In a bubble shutter configured to pass through an optical path, the amount of heat generated by the heating element is changed stepwise or steplessly according to a command signal from the control circuit, and the amount of heat generated by the heating element is changed. A light amount control method for a bubble shutter, characterized in that the size of the bubbles in the liquid (the amount of expansion in the optical path direction) is changed stepwise or steplessly to adjust the amount of emitted light. .