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Hatanaka, Isamu; |
Image forming method

In a method for forming an image, a liquid crystal shutter array or matrix is positioned between a photosensitive material and a light source, and light emitted by the light source to the photosensitive material is controlled by driving each liquid crystal shutter portion constituting a picture element of the liquid crystal shutter array or matrix. Drive of the liquid crystal shutter portion is controlled by using the driving pulses having a pulse width shorter than the response time of the liquid crystal and by changing the pulse width or the number of the driving pulses in accordance with an image signal. The photosensitive material is of the type which can express a half tone. When the liquid crystal shutter array or matrix which intercepts light upon application of a voltage is used, the driving pulses are applied prior to exposure to intercept light. Then application of the driving pulses is stopped for a time corresponding to the image signal so that the liquid crystal shutter allows the light to pass therethrough.


I claim:
1. An image forming method in which a liquid crystal shutter array operable as a light valve is positioned between a photosensitive material and a light source, and light emitted by said light source to said photosensitive material is controlled by driving each liquid crystal shutter portion constituting a picture element of said liquid crystal shutter array, thereby conducting imagewise exposure of said photosensitive material to the light, wherein the improvement comprises controlling the drive of said liquid crystal shutter portion by supplying to said liquid crystal shutter portion driving pulses having a pulse width shorter than the response time of the liquid crystal and by changing the effective duration of said driving pulses as a function of image density information of an image signal, and using a photosensitive material which can express a half tone as said photosensitive material.
2. A method as defined in claim 1 wherein a photosensitive material exhibiting the toe-cut characteristics in used as said photosensitive material.
3. A method as defined in claim 1 wherein said liquid crystal shutter array is of the type normally intercepting the light.
4. A method as defined in claim 3 wherein said liquid crystal shutter array or said liquid crystal shutter matrix is a parallel nicols type twisted nematic liquid crystal shutter array.
5. An image forming method in which a liquid crystal shutter array operable as a light valve is positioned between a photosensitive material and a light source, and light emitted by said light source to said photosensitive material is controlled by driving each liquid shutter portion constituting a picture element of said liquid crystal shutter array, thereby conducting imagewise exposure of said photosensitive material to the light, wherein the improvement comprises using a liquid crystal shutter array of the type intercepting light upon application of a voltage thereto, continuously applying a pulse voltage having a pulse width shorter than the response time of the liquid crystal to the liquid crystal shutter panel prior to the exposure of said photosensitive material to the light, thereby intercepting the light, thereafter stopping the application of the voltage to the liquid crystal shutter for a time corresponding to an image signal so that the liquid crystal shutter allows the light to pass therethrough, and using a photosensitive material which can express a half tone as said photosensitive material.
6. A method as defined in claim 5 wherein a photosensitive material exhibiting the toe-cut characteristics is used as said photosensitive material.
7. A method as defined in claim 5 wherein said liquid crystal shutter array is a crossed nicols type twisted nematic liquid crystal shutter array of matrix.
8. A method as defined in claim 1 wherein the effective duration of said driving pulses is changed by changing the pulse width thereof.
9. A method as defined in claim 1 wherein the effective duration of said driving pulses is changed by changing the number of driving pulses that are supplied to said liquid crystal shutter portion during a predetermined period.
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