Abstract: A multi-function printer can print on two different types of record media, one of which types of record media is continuous, such as may be used for printing receipts, and is stored within the printer, and a second of which types of record media is discontinuous, may be of varying thickness, and is introduced from the exterior of the printer. A reversible motor and associated transmission mechanism provide means for driving the two types of record media, and a pivotally mounted solenoid-driven platen arm provides for selective engagement of driving means in the printer and for altering the gap between the printhead and the platen of the printer in accordance with the thickness of the record media to be printed upon.

Abstract: In a slip printer, the slip is inserted or placed on the slip table at 90.degree. to normal orientation to accommodate slips which are wider than the print station. Character data and space data are input into memory and printing is done by shifting out character data along with space data on either side of the character in dot by dot manner. A pattern processing section is capable of changing the arrangement of the dot pattern read out from memory, a space data generating section is adapted to output space data signals before and after output of pattern data from the processing section, and a print data buffer stores the process data and the space data for one line dot row prior to printing.

Abstract: A reflection type overhead projector employs a Fresnel concave mirror adapted for allowing a transparency to be put on the mirror surface thereof. The beam of light emitted from a light source lamp is reflected by the Fresnel concave mirror, enters a projecting lens and then is projected on a screen. A reflecting mirror is interposed in an optical path between the Fresnel concave mirror and the projecting lens to thereby bend the optical path. The Fresnel concave mirror, the light source lamp and the projecting lens are all mounted to a single case.

Abstract: A self-excited switching type D.C. power supply for producing a stabilized output signal. The power supply is provided with a rectifier, a primary winding of a transformer, a switching transistor and a resistor connected in series with one another between first and second input terminals of the power supply. The transformer is further provided with a secondary winding, a Zener diode, a capacitor and a resistor connected in series with a photocoupler. The photocoupler is connected in series with a pair of control transistors which control the operation of the switching transistor. The switching frequency of the switching transistor is stabilized by providing a quiescent time period during which the switching transistor is disabled.