| 摘要 |
<p>A matrix printer impact energy control is disclosed wherein the impact energy supplied to the drive solenoids of matrix print heads is maintained substantially constant notwithstanding variations in the printer power supply output. The hammer power supply voltage is monitored and coupled, together with a derived reference voltage to a summing amplifier which is then pulse width modulated to produce a pulsed hammer drive output having constant print energy. The print energy may be increased to provide multiple copy printing capability. A single impact energy control circuit controls all of the print hammers of each print head. Synchronization of the pulse width modulator is provided by a variable frequency clock from which the pulse width modulator trigger frequency is derived.</p> |
