| 摘要 |
PURPOSE: To dispense with the use of a register mark which is to be specially provided by recognizing the detected output levels of all sensors as a linear part for subsequent register control, when the output levels satisfy predetermined criteria. CONSTITUTION: The linear array of photosensors of photodiodes 1A-1F is arranged orthogonally with the running direction of a web 3 on which an image is printed. These sensors receive a reflected light from the area of the web 3 irradiated with a light source 5. Each of the sensors is connected to an addition AGC amplifier 6, the output terminal of which is connected, in parallel, to comparator systems 7-11. Output signals from these comparator systems 7-11 are entered to an AND gate 12. When a length area is detected, the comparator systems output a binary signal '1'. When the signal indicates a value exceeding a specified value, the system 7 generates an output HIGH, initiating the operation of a counter 7B. Finally, the comparator 11 interprets whether an image area corresponding to an output level LOW from the sensors has an absolute value which is low enough to correspond to REF 5. |
