Abstract: A printer includes a system for automatically adjusting the drive voltage of a print head according to a predetermined rank characteristic of the head. This is accomplished by initially producing a reference signal along a signal line. The reference signal is delayed by a delay circuit by an amount corresponding to the rank characteristic of the print head. The delayed reference is then compared to the reference signal thereby resulting in the detection of the delay time therebetween. A control signal is subsequently generated that corresponds to the delay time. The control signal is connected to a print head driver through the signal line so that a drive voltage may be generated during a subsequent time interval, the drive voltage corresponding to the rank characteristic of the print head.

Abstract: A manual printer includes a head unit. The head unit includes a recording head, a running roller and a projection coupled to a housing via a universal joint. The head unit can be tilted relative to the housing. The position of the head unit relative to a recording medium P is maintained even if the housing is tilted in any direction. A gap and an angle between the recording head and the recording medium P can be fixed which enables a stable printing operation.

Abstract: A remaining liquid quantity detecting device to detect the quantity of the liquid remaining in a tank by applying a voltage to a pair of electrodes 1 and 2 set in the tank and detecting the electric resistance which will change under the influence of the liquid existing between the electrodes 1 and 2, wherein a standard voltage 10 having a predetermined electric potential is applied to both of the electrodes 1 and 2 at a non-detection time, and one electric potential between the electrodes 1 and 2 is changed so as to alternate on the basis of the standard voltage.

Abstract: A wet type image developing device for applying a developing liquid over an electrostatic latent image provided on a photosensitive member on a rotary drum. The developing device has an inner tubular member and an outer tubular member. The developing liquid is pressurizingly supplied into the inner tubular member, and the outer tubular member is radially outwardly expandable by the liquid introduction for providing a facial contact of the outer tubular member with the photosensitive member. The developing liquid is transuded into the outer tubular member and is oozed out for applying the liquid over the photosensitive member. If no liquid is supplied to the inner tubular member, the outer tubular member is radially inwardly shrunken for the separation of the outer tubular member from the photosensitive member.