| 摘要 |
PURPOSE:To obtain the paper feeder with improved operability by alleviating the holding condition of a stepping motor through the detection of manual paper feeding on a printer when its feeding is performed. CONSTITUTION:When manual paper feeding is performed and a stator of a stepping motor 1 is at stationary, a rotor is held by a constant force under the excitation of only one set of rotors in an excitation circuit 8. If a platen knobs 2 begins to be turned manually, the rotor of the stepping motor 1 rotates through a timing belt 5, generating a back electromotive force in the excitation circuit 8. This back electromotive force is detected by a detection circuit 9, generating a logic (1) detection signal. A logic (1) stationary signal S1 and a logic signal S2 are supplied to an AND circuit 10 and their logic product signal S3 is supplied to a dividing circuit 7 in the form of logic. Consequently, an excitation current which excites a specific phase is weakened, the holding force of holding the rotor of the stepping motor in weakened. Thus, manual paper feed is facilitated. |
