Abstract: The present invention provides a method and a device for printing images on halves of both sides of a group of receiving sheets by passing each sheet seriatim four times directly in succession through a printing station thereby printing the four halves of the sheet. The sheets thus printed are together folded double to form a book in which the sequence of the images corresponds to the sequence of the original images.

Abstract: The present invention provides a method and a device for printing images on halves of both sides of a group of receiving sheets by passing each sheet seriatim four times directly in succession through a printing station thereby printing the four halves of the sheet. The sheets thus printed are together folded double to form a book in which the sequence of the images corresponds to the sequence of the original images.

Abstract: The present invention provides a method and a device for printing images on halves of both sides of a group of receiving sheets by passing each sheet seriatim four times directly in succession through a printing station thereby printing the four halves of the sheet. The sheets thus printed are together folded double to form a book in which the sequence of the images corresponds to the sequence of the original images.

Abstract: In an ultrasonic system for detecting and distinguishing between superimposed and single sheets moving along a transport path, the frequency of the ultrasonic source is kept tuned to the natural frequency of the total system so that the phase displacement detected when a sheet-like object is present between the source and the ultrasonic receiver represents characteristics of the object itself. When no sheet-like object is present the receiver and the source are connected in a feedback circuit producing a certain natural frequency comparable to that which occurs with proximities between a microphone and a loud speaker, and the frequency of an oscillator is tuned to this natural frequency. When a sheet-like object is present the tuned oscillator frequency is applied to the ultrasonic source and its phase is compared with the phase of the ultrasonic signal at the receiver.

Abstract: A copying apparatus which automatically produces duplex copies in logical page sequence from simplex originals comprises transport paths for conveying originals to and from a copying position, imaging means for producing an image of an original onto a copy sheet, a first hopper to collect single-sided copy sheets, a second hopper to collect duplex copies and delivery means for delivering the duplex copies into the second hopper. The delivery means comprises a first delivery path and a second delivery path, and a detector in the transport path of the originals determines whether the number of originals to be copied is even or odd, thus causing the duplex copies to be delivered through the first or the second delivery path, depending on whether an even or an odd number of originals has been detected by the detector. The apparatus disclosed is also suited for programmed production of simplex copies from simplex originals, duplex copies from duplex originals, and simplex copies from duplex originals.