Patent EA-000440-B1 (EA)
Title: Exposure head and printer
Inventor: GOMI MASAO
IPC: B41J2/45
Filed: 1997-07-07
Abstract: 1. An exposure head comprising: a light source portion in which a plurality of semiconductor light sources capable of irradiating a photosensitive sheet with exposure light for forming an image on the photosensitive sheet are arranged; a front surface portion having a plurality of small openings at positions corresponding to said semiconductor light sources; and a light shielding portion having a plurality of enclosing openings at positions corresponding to the semiconductor light sources, said enclosing openings having a size that allows said semiconductor light sources to be housed therein; said front surface portion and said light shielding portion being layered on said light source portion so that said front surface portion faces a photosensitive sheet and said light shielding portion is disposed between said front surface portion and said light source portion. 2. An exposure head according to Claim 1, wherein said front surface portion has a non-reflective surface that faces a photosensitive sheet. 3. An exposure head according to Claim 1, wherein said front surface portion has a black surface that faces a photosensitive sheet. 4. An exposure head according to Claim 1, wherein said enclosing openings have reflective inside surfaces. 5. An exposure head according to Claim 1, wherein said light shielding portion has a strength to support said exposure head, and said front surface portion and said light source portion are mounted to said light shielding portion. 6. An exposure head according to Claim 1, wherein said semiconductor light emitting elements are LEDs capable of emitting exposure light of a color of a primary color group of red, green and blue, or a color of a primary color group of cyan, magenta and yellow. 7. An exposure head according to Claim 1, wherein said exposure head is a scanning type exposure head that moves relative to a photosensitive sheet in a scanning direction to form an image. 8. A printing apparatus according to Claim 7, further comprising a sheet conveyance apparatus that conveys a photosensitive sheet relative to said exposure head. 9. A printing apparatus according to Claim 7, wherein said semiconductor light sources are arranged so that when said exposure head moves and performs exposure, said semiconductor light sources can irradiate a same location on a photosensitive sheet with exposure light. 10. A printing apparatus according to Claim 7, wherein said light source portion has a plurality of semiconductor light source groups capable of emitting exposure light of different colors, and said plurality of semiconductor light source groups are arranged so that when said exposure head moves and performs exposure, said semiconductor light source groups can irradiate a same location on a photosensitive sheet with exposure light of the different colors. 11. A printing apparatus according to Claim 10, wherein at least one of said semiconductor light source groups has a plurality of semiconductor light sources. 12. A printing apparatus according to Claim 7, comprising a developing apparatus having a rotating body capable of developing a photosensitive sheet by pressurization while being moved in the scanning directions synchronously with said exposure head by said head conveying apparatus.