Apparatus and method for driving an optical printer having a liquid crystal optical switch

A method for driving an optical printer having at least one liquid crystal optical switch including a ferroelectric liquid crystal layer interposed between a pair of substrates having electrodes on confronting surfaces thereof, the at least one liquid crystal switch being disposed between light source means and a photosensitive surface, a light transmission state of the at least one liquid crystal optical switch being controlled by application of a voltage signal to the at least one liquid crystal optical switch so as to control light transmission to the photosensitive surface, comprising the steps of:

• applying a first voltage signal to the liquid crystal layer of the at least one optical switch in a writing period in which the light transmission state is determined in accordance with a printing signal for printing;
• applying a second voltage signal having a DC component of one polarity to the liquid crystal layer of the at least one optical switch in a retention period;
• applying a third voltage signal having a DC component of an opposite polarity to the liquid crystal layer of the at least one optical switch in a reset period in which the at least one liquid crystal optical switch is placed in a light interrupting state;
• and
• applying a fourth voltage signal having a DC component of the one polarity to the liquid crystal layer of the at least one optical switch in a period other than an excluding period which is formed from the writing period, retention period and reset period.