Abstract: A print head for ink jet printer having a reduced length in a main scanning direction and an elongated length in an auxiliary scanning direction perpendicular to the main scanning direction. A plurality of linear print head modules are arrayed in the auxiliary scanning direction, and each linear print head module extends in a slanting direction with respect to the main scanning direction by a predetermined angle. Further, each linear print head module has a width in a direction perpendicular to its extending direction. The slanting angle and the width determine scanning pitch extending in the auxiliary scanning direction and can reduces the length of the print head in the main scanning direction.

Abstract: In an electrophotographic printer, a photoconductive drum is scanned with a light spot provided by scanning light sources to electrostatically form a latent image with dot on it. The light sources comprise at least two LED print heads different in linear density are provided to print out data different in linear density on one and the same page.

Abstract: A cleaning apparatus for a copier includes a photoconductor-cleaning rotating fur brush disposed within a housing. In order to prevent toner buildup and resultant flaking within the housing, the brush and housing are relatively movable so that the brush can periodically clean the housing.

Abstract: A driving motor of the type employing pneumatic bearings is improved by reducing a weight moment of an upper pad by cutting away a portion thereof, to make the gaps of the bearing pads of the motor more nearly uniform.

Abstract: A yoke mechanism for a copier is provided with an engagement mechanism capable of holding the yoke at a position intermediate the retracted and transfer positions, at which position the yoke may be easily loaded with paper, and then moved to the transfer position, in one simple operation.

Abstract: The print timing, with which a print hammer impacts a desired type moving on a type carrier, is advanced and then retarded or vice versa during test printing to find an ideal print timing. The amount of advancing and retarding respectively correspond to the negative and positive tolerance limits of the variation in flight time of the print hammer. During test printing the print timing is further advanced and/or retarded so that printed samples are perfect, and then the timing, which has been further advanced or retarded, is used to determine the ideal print timing. Circuit arrangements for performing the method are also disclosed as embodiments of the invention.

Abstract: In a paper feed control system employing a pulse motor steppingly rotatable in response to driving pulses, paper feeding is controlled by a prepunched format tape wherein line pulses generated every one line feeding of the paper are in synchronism with perforations detected from the format tape. Briefly, the format tape is moved by the pulse motor, and when a first perforation is detected therefrom a predetermined number of the driving pulses is applied to the pulse motor, whereby the format tape is moved to an approximate midpoint of the perforation. A first line pulse is generated in response to the predetermined number of the driving pulses so that the line pulse is generated in approximate midpoint of the first perforation. Accordingly, the succeeding line pulses are generated in the approximate midpoints of the succeeding perforations.