Abstract: A computer controlled printer is capable of printing at different print densities. This makes it possible to automatically determine an optimum print density according to a normal operational mode with serious consideration given to print quality and an economy operational mode with serious consideration given to operating costs, thereby decreasing the print consumables. The printer has a print mechanism section for printing papers according to print data and a print controlling section for controlling the print mechanism section. The print controlling section selects either a print density in a normal mode or a print density in an economy mode according to the normal/economy instructions and controls the print density of the print mechanism section correspondingly.

Abstract: A printer capable of operation in an economy mode as well as in a normal mode. The printer includes a print mechanism for printing in accordance with print data. The printer also includes a print controller which controls the print mechanism. The printer is provided with a mode of operation selector for selecting between a normal mode of operation in which the print quality is relatively emphasized and an economy mode of operation in which operating costs are relatively emphasized. The print controller controls the print density at a first level when the normal mode of operation has been selected and at a second reduced level when the economy mode of operation has been selected.

Abstract: An electrophotographic recording apparatus comprising a rotatable photosensitive drum and unit for electrifying the drum, depositing an electrostatic latent image on the drum, developing the latent image, transferring the image on the drum to printing paper, and optical-deelectrifying the drum. In this method, the optical deelectrification unit is located at a position opposite to the drum with respect to a passage of the printing paper, and an optical deelectrification beam is irradiated to the drum only when the printing paper interrupts an optical path of the deelectrification light toward the drum.

Abstract: A push-push mechanism of a pushbutton operating shaft characterized in that a driving member of a tubular body is rotatably supported upon the operating shaft of the push button. The driving member is provided with a protuberance extending orthogonally to the direction of movement of the operating shaft, and a cam plate formed with a heart-shaped groove in its upper surface is received in a frame so that the cam plate can move upwardly by being guided by the inner wall of the frame.