| 摘要 |
PURPOSE:To suppress unevenness of printing due to white lines even if an original has low density and halftone gradation by inserting a resistance element for adjusting angular velocity in either phase A or phase B of a stepping motor and eliminating dispersion between the angular velocities at phases A and B of the stepping motor. CONSTITUTION:A resistance element for adjusting angular velocity is inserted in series into a phase A and phase A winding by opening angular velocity adjusting switches S1 and S2 on the common terminal side at phase A, the inverse of A thus delaying a rise of an exciting current at phase A and slowing down an angular velocity of the stepping motor at phase A. Similarly, a rise of an exciting current at phase B is delayed and an angular velocity of the stepping motor at phase B is slowed down by opening angular velocity adjusting switches S1 and S2 on the common terminal side at phase B, the inverse of B Therefore if unevenness of printing due to white lines may result, dispersion between the angular velocities at phases A and B is reduced by opening either of the switches for adjusting angular velocity the exciting current of which rises faster than the other. Thus, unevenness of printing due to white lines can be suppressed. |
