LIGHT BEAM SCANNER AND LIGHT BEAM SCANNING METHOD

• Main Authors: WADA YASUYUKI, MASAKI YUTAKA
• Format: Patent
• Language: English
• Published: 19.12.2000
• Edition: 7
• Subjects: CORRECTION OF TYPOGRAPHICAL ERRORS; ELECTRIC COMMUNICATION TECHNIQUE; ELECTRICITY; i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; LINING MACHINES; PERFORMING OPERATIONS; PICTORIAL COMMUNICATION, e.g. TELEVISION; PRINTING; SELECTIVE PRINTING MECHANISMS; STAMPS; TRANSPORTING; TYPEWRITERS

PROBLEM TO BE SOLVED: To detect a plotting abnormality due to the abnormality of speed in the sub-scanning direction and to efficiently scan a photosensitive material such as film and a glass substrate to be scanned by detecting a state, that the moving speed relative to a scanning surface in the sub-scanning direction of a light source part exceeds a specified reference, as an abnormality and making the specified standard variable. SOLUTION: A target displacement curve V0 or a displacement curve V2 is drawn when the speed in the sub-scanning direction is fixed or fast by a position Y in the sub-scanning direction of a plotting head. A scanning starting position reach signal XSS is turned on when the plotting head reaches scanning positions Y0, Y1,... and the scanning is started by the plotting head when a scanning part control signal CSS is turned on. A scanning error timing judging signal Etj is turned on after elapse of time tj since the control signal CSS is turned on. When the plotting head is moved at high speed to reach a position Y2 at time T1 before time T12 when the judging signal Etj is turned on and a reach signal XSS is turned on, such a state is judged to be abnormal.