Image forming apparatus

• US 4,958,912 A
• Filed: 07/06/1988
• Issued: 09/25/1990
• Est. Priority Date: 07/07/1987
• Status: Expired due to Term

• Current Assignee: Canon Ayutthaya Limited (Canon Inc.)
• Original Assignee: Canon Ayutthaya Limited (Canon Inc.)
• Inventors: Inaba, Yutaka, Kojima, Makoto, Kawagishi, Hideyuki, Kaneko, Shuzo
• Primary Examiner(s): Miller, Stanley D.
• Assistant Examiner(s): MAI, HUY KIM
• Application Number:
  US07/215,791
• Time in Patent Office: 811 Days
• Field of Search: 350/332, 350/333, 350/350 S, 340/805, 340/811, 355/234
• US Class Current: 349/2
• CPC Class Codes: G06K 15/1252 using an array of light modulators, e.g. a linear array
• CPC Class Codes: H04N 1/19505 Scanning picture elements spaced apart from one another in at least one direction
• CPC Class Codes: H04N 1/1951 in one direction
• CPC Class Codes: H04N 1/19547 Apertures
• CPC Class Codes: H04N 1/40031 for a plurality of reproducing elements simultaneously

Abstract

An image forming apparatus includes a light source; an optical shutter unit comprising a pair of parallel substrates respectively having a plurality of scanning electrodes and a plurality of data electrodes disposed to intersect with each other to form a matrix electrode structure on their opposite surfaces, and a ferroelectric liquid crystal disposed between the pair of substrates so as to form a microshutter at each intersection of the scanning electrodes and data electrodes; an optical system for forming an image at a desired position with light transmitted through the optical shutter unit; a photosensitive member as a medium for recording the thus formed image; a scanning side drive circuit for applying a scanning voltage signal to the plurality of scanning electrodes so as to sequentially select at least one scanning electrode in a prescribed cycle; and a data side drive unit for applying data voltage signals to the plurality of data electrodes in synchronism with said scanning voltage signal. Image data are transferred on the optical shutter unit corresponding to the movement of the photosensitive member so as to move an image formed thereby on the photosensitive member while keeping the relative position of the image with respect to the photosensitive member.

Claims

1. An image forming apparatus comprising:

a light source;

an optical shutter unit comprising a pair of parallel substrates respectively having a plurality of scanning electrodes and a plurality of data electrodes disposed to intersect with each other to form a matrix electrode structure on opposite surfaces thereof and a ferroelectric liquid crystal disposed between said pair of substrates so as to form respective microshutters at each intersection of said scanning electrodes and said data electrodes, wherein said microshutters are arranged in a plurality of rows corresponding to said plurality of scanning electrodes;

an optical system for forming an image at a desired position with light transmitted through said optical shutter unit;

a photosensitive member;

a scanning line drive circuit for applying scanning voltage signals to said plurality of scanning electrodes so as to sequentially select at least one scanning electrode in a prescribed cycle;

a data line drive circuit for applying data voltage signals to said plurality of data electrodes in synchronism with said scanning voltage signal;

means for applying first image data to first ones of said microshutters on a first particular scanning electrode in a first scanning cycle and applying second image data associated with said first image data to provide desired gradation of the image to second ones of said microshutters on a second particular scanning electrode in a subsequent second scanning cycle;

means for controlling the scanning line drive circuit to provide different opening periods to said microshutters in respective rows; and

means for moving said photosensitive member so that a particular position on said photosensitive member corresponds to said first particular scanning electrode in the first scanning cycle, the particular position further corresponding to said second particular scanning electrode in the second scanning cycle.

2. An apparatus according to claim 1, wherein said microshutters are arranged in a staggered fashion.

3. An apparatus according to claim 1, wherein third image data are applied to third ones of said microshutters on a third particular scanning electrode in a third scanning cycle.

4. An apparatus according to claim 1, wherein said ferroelectric liquid crystal comprises a chiral smectic liquid crystal.

5. An apparatus according to claim 4, wherein said chiral smectic liquid crystal is disposed in a layer thin enough to release its own helical structure.

6. An apparatus according to claim 1, wherein said microshutters are arranged in a predetermined number N of rows and are controlled to have opening periods in ratios of 1:

2;

4;

8;

. . . . ;

2.sup.(N-1) for the respective rows.

7. An apparatus according to claim 1, wherein said first and second particular scanning electrodes are disposed adjacent to each other.

8. An apparatus according to claim 1, wherein the different microshutter opening periods are given by application of scanning pulses with different durations.

9. An image forming apparatus comprising:

a light source;

an optical shutter unit comprising a pair of parallel substrates respectively having a plurality of scanning electrodes and a plurality of data electrodes disposed to intersect with each other to form a matrix electrode structure on opposite surfaces thereof and a ferroelectric liquid crystal disposed between said pair of substrates so as to form respective microshutters at each intersection of said scanning electrodes and said data electrodes;

an optical system for forming an image at a desired position with light transmitted through the optical shutter unit;

a photosensitive member;

a scanning line drive circuit for applying scanning voltage signal to said plurality of scanning electrodes so as to sequentially select at least one scanning electrode in a prescribed cycle;

a data line drive circuit for applying data voltage signals to said plurality of data electrodes in synchronism with said scanning voltage signal;

means for applying image data to a first microshutter at a first intersection of a first particular scanning electrode and a particular data electrode to provide said first microshutter with a first optical state in a first scanning cycle and applying image data in accordance with gradation data of the image to a second microshutter, at a second intersection of a second particular scanning electrode and the particular data electrode, to provide said second microshutter with a second optical state in a subsequent second scanning cycle; and

means for moving said photosensitive member such that a particular position on said photosensitive member corresponds to said first particular scanning electrode in the first cycle and to said second particular scanning electrode in the subsequent second cycle.

10. An apparatus according to claim 9, wherein the first optical state is provided for a first duration in the first cycle and the second optical state is provided for a second duration in the second cycle, said first duration and second duration being different from each other.

11. An apparatus according to claim 10, wherein the first duration is twice as long as the second duration.

12. An apparatus according to claim 9, wherein said ferroelectric liquid crystal comprises a chiral smectic liquid crystal.

13. An apparatus according to claim 12, wherein said chiral smectic liquid crystal is disposed in a layer thin enough to release its own helical structure.

14. An image forming apparatus, comprising:

a light source;

an optical shutter unit comprising a pair of parallel substrates respectively having a plurality of scanning electrodes and a plurality of data electrodes disposed to intersect with each other to form a matrix electrode structure on opposite surfaces thereof and a ferroelectric liquid crystal disposed between said pair of substrates so as to form respective microshutters at each intersection of the scanning electrodes and data electrode;

an optical system for forming an image at a desired position with light transmitted through said optical shutter unit;

a photosensitive member;

a scanning line drive circuit for applying scanning voltage signals to said plurality of scanning electrodes so as to sequentially select at least one scanning electrode in a prescribed cycle;

a data line drive circuit for applying data voltage signals to said plurality of data electrodes in synchronism with said scanning voltage signal; and

means for moving said photosensitive member such that a first microshutter at the intersection of a first particular scanning electrode and a particular data electrode is supplied with image data so as to provide said first microshutter with a first optical state which corresponds to said first particular scanning electrode in a first scanning cycle, and such that in a subsequent second scanning cycle, said photosensitive member is moved to correspond to a second particular scanning electrode having thereon a second microshutter on said particular data electrode receiving image data in accordance with gradation data of the image so as to provide said second microshutter with a second optical state.

15. An apparatus according to claim 14, wherein the first optical state is provided for a first duration in the first cycle and the second optical state is provided for a second duration in the second cycle, the first duration and second duration being different from each other.

16. An apparatus according to claim 15, wherein the first duration is twice as long as the second duration.