Postage meter with means for preventing unauthorized postage printing

The improvement according to claim 3, including said second control signal connected for driving said first stage amplifying circuit, said capacitor charging during the time period between successive pulses and discharging during the time interval of duration of the respective pulses, said interposing means being operated by said second stage amplifying circuit to permit operation of said shutter means during the capacitor charging time period, and said discharging time interval being sufficiently small to permit continuous operation of said shutter means.

In an electronic postage meter having computer means and means operable for printing a postage value, wherein said computer means includes means for authorizing printing of said postage value, and said postage meter having shutter means operable for normally preventing operation of said postage printing means, and having interposing means including an interposer and a solenoid, wherein said solenoid is operable for causing said interposer to alternately prevent and permit operation of said shutter means, an improvement for controlling operation of the solenoid, said improvement comprising:

• (a) means for generating a first control signal for normally operating said solenoid to prevent operation of said shutter means;
• (b) means for generating a second control signal for operating said solenoid to permit operation of said shutter means, said second control signal being generated when said authorizing means has authorized printing the postage value, and said second control signal is a series of periodically generated pulses during a printing cycle, each pulse having a predetermined time duration.