Abstract: In an image forming apparatus, in a case of duplex printing, a sheet is transported toward an image forming device along a sheet transport route, the image forming device forms an image on a first face, which is one of faces of the sheet, a reverse transport device reverses the front and back faces of the sheet and transports the sheet to a position upstream of a show-through reading device in a sheet transport direction, and the show-through reading device reads a second face, which is another face of the sheet. Then the show-through detector decides whether a show-through has occurred, on a basis of the image that has been read.

Abstract: A novel means by which HCMV infection can be detected with a high sensitivity and whose practicality is high is disclosed. The present inventors synthesized as many as 15 kinds of HCMV proteins in their full length forms, and intensively studied their reactivities with sera from HCMV-infected patients to find that all the infected patients can be detected without fail when using the pp28 full length protein as an antigen. The pp28 full length protein can be synthesized and purified as a recombinant protein in a large scale by using Escherichia coli, and can be commercially used as an antigen for HCMV tests.

Abstract: A video recording system is provided with a copy guard arrangement which can readily discriminate a video signal having pseudo horizontal synchronizing pulses in a portion of a vertical blanking interval, from a normal video signal, without deteriorating the quality of recorded pictures. Preferably, an analog circuitry or a microcomputer is designed to count the horizontal synchronizing pulses received during a predetermined portion of the vertical blanking interval, and to discriminate a copy-guarded video signal from an unguarded video signal in accordance with the result of the counting. In the case of the copy-guarded video signal, an inhibit signal is produced to prevent a normal recording operation.

Abstract: A rotary compressor includes a top clearance volume formed between a cylinder chamber and at least one delivery valve. Another top clearance volume, in communication with the cylinder chamber, produces a reverse flow of compressed fluid which generates pulsations adapted to offset a high frequency component of pulsations generated in the cylinder chamber by compressed fluid reversely flowing from the first top clearance volume to the cylinder chamber. Thereby the high frequency component of pulsations generated in the cylinder chamber is eliminated, and a low-noise rotary compressor is provided.

Abstract: A BTL power amplifier comprises main and inverse amplifier units having the same constitution but producing outputs inverted from each other. A low impedance load is directly connected between the output ports of the main and inverse amplifier units. The present BTL power amplifier further comprises a first operation control circuit which activates only the main amplifier unit after the power switch is turned on, and a second operation control circuit which maintains the output port of the inverse amplifier unit in a floating state for a predetermined period of time after the activation of the main amplifier unit is begun. Thus, the present BTL power amplifier produces no pop noise when the power supply is initiated.

Abstract: A bias circuit for generating bias voltages or bias currents including first and second elements for generating a voltage corresponding to the sum of two voltage drops in a forward p-n junction; first and second transistors for generating a negative feedback current; at least one resistor for determining the value of a constant current for generating bias voltages; a negative feedback circuit; a third resistor connected in the feedback circuit, and; a starting element for supplying currents to the first and second elements and to the first and second transistors in an initial state when the power is turned on, whereby the feedback circuit operates to generate the constant current which is used for forming bias voltages.