公开(公告)号：DE3269555D1

公开(公告)日：1986-04-10

申请号：DE3269555

申请日：1982-04-07

Applicant: IBM

Inventor： BILDSTEIN CARL ROBERT ,  HEIBEIN HARRY PARMER ,  MATHEWS HARLAN PAUL

IPC: B41J2/175 ,  B41J23/32 ,  H01F7/18 ,  B41J3/04

Abstract: An ink jet pump is switched from a mechanically off or idle state to a mechanically on or active state with no drift in pressure output by maintaining the pump at the same point in its force-temperature characteristic when it is on and off. This is accomplished by driving the pump in both the active and idle states with signals that dissipate the same amount of power in the pump. The frequency of the idle state signals is high enough that the pump can not mechanically respond. The power dissipations in the active and idle states are matched by adjusting the current build-up and current decay through the coil of the pump during the idle state. When the RMS current through the coil in the active state equals the RMS current in the idle state, the power dissipations are matched.As shown voltage regulator circuit (20) provides potential (V2) and current is drawn through the pump solenoid (12) via transistor (14) or (16). When the pump is active a 60 Hz signal is applied to transistor (14) and when the pump is idle a 26 KHz signal is applied to transistor (16). The 60 Hz signal switches transistor (14) on and off, alternately reverse and forwardly biasing diode (30) and causes the current I to build-up and decay. This occurs at a frequency the pump diaphragm can follow. Operation is similar at 26 KHz but the pump stops because it cannot operate at the high frequency. The idle current level is set by adjusting resistor (R3).