Abstract: A print head for non-impact printer is, for example, an LED head which comprises a plurality of light-emitting elements, LED drivers for selectively causing a drive current to flow into the light-emitting elements on the basis of the print data, a non-volatile memory for storing the modification data related to the value of the drive current. The modification data are determined in advance at the manufacturing process on the basis of the measured result when the light-emitting elements were driven by the LED driver so that all the light-emitting elements emit substantially same amount of light at the printing operation.

Abstract: Data are transmitted from a control device through an interface cable to a set of driver devices in synchronization with an external clock signal, or a complementary pair of external clock signals. The signal line or lines carrying the external clock signal or signals are terminated at both ends by resistors with resistance values matching the characteristic impedance of the interface cable. Each driver device has a comparator that compares the external clock signal with a regulated reference voltage, or compares the two complementary external clock signals with each other, and thereby generates an internal clock signal. The driver devices receive the data in synchronization with these internal clock signals.

Abstract: A printer receives a bit-mapped image signal representing an arbitrary bit-mapped image, and generates an independent pattern signal having a certain dot density, representing a shade of gray. The printer discriminates between edge dots and interior dots in the bit-mapped image signal, and generates a corresponding discrimination signal. A logic circuit outputs edge dots that are present in the bit-mapped image signal, and interior dots that are present simultaneously in the bit-mapped image signal and pattern signal. The dots output by the logic circuit are printed to produce outlines filled with a shade of gray.

Abstract: A printer includes a controller for providing a sequence control for the printer in its entirety in response to a control signal and a video signal from another controller. A printer head is adapted for latching and printing a printing data signal transmitted from the controller.

Abstract: The operation of an automatic sheet feeder provided with a plurality of sheet hoppers which are used selectively to feed sheets to a printer is controlled. A control unit of the printer supplies a multiplex control signal including a hopper select signal and a sheet delivery signal to the automatic sheet feeder through a single signal line. The width of pulses of the hopper select signal is smaller than a predetermined time, while the width of the sheet delivery signal is greater than the predetermiend time. The pulses of the multiplex control signal are compared with the predetermined time to discriminate the hopper select signal and the sheet delivery signal from each other. That sheet hopper corresponding to the number of pulses of the hopper select signal is selected, and then the automatic feeding of sheets from the selected sheet hopper commences upon the reception of the sheet delivery signal.

Abstract: A method of controlling a cut-sheet feeder installed on a printer to feed a cut sheet from a sheet hopper (1) included in the cut-sheet feeder to the printing unit of the printer at a sheet feeding speed corresponding to that of the printer. The printer gives a correction signal (S.sub.1) of a predetermined pulse width to the cut-sheet feeder, and then the cut-sheet feeder converts the pulse width of the correction signal into a corresponding number of pulses of a clock signal generated by its control unit (25), and obtains the difference between the number of pulses of the clock signal and a predetermined reference value to determine the deviation of the frequency of the clock signal from a reference frequency. The difference between the number of pulses of the clock signal and the reference value is added to a reference motor controlling value for driving a stepping motor (4) at a reference speed to obtain a corrected motor controlling value. When the printer gives a sheet feed command signal (S.sub.

Abstract: A method of automatically inserting a printing paper in a hopper of an automatic paper feeder or a manual insertion printing paper inserted from a manual paper input slot. Upon receiving an instruction to insert a printing paper by a printer, a platen is first rotated. Thereupon, provided the presence of the printing paper is detected by a sensor even with the platen being rotated by a prescribed amount, a paper feed motor of the automatic paper feeder is rotated for obtaining a printing paper from the hopper. While, provided the presence of a printing paper is detected before the platen is rotated by the prescribed amount, the paper feed motor is not rotated, it being assumed that the manual insertion of a printing paper has been already performed. After detected the presence of the printing paper, the platen is rotated by a prescribed amount to cause the printing paper to be moved to a position where a first line of the printing paper faces the face of the printing head.

Abstract: A paper feeding control system of an automatic paper feeder has a setting device for enabling a position to head a printing medium to be reset. The setting device consists of a read/write enable nonvolatile memory for holding a reset value of the heading position of the printing medium. Upon taking in and setting the printing medium, an operating panel switch is operated to correct the heading position of the printing medium. In addition, the corrected value is again written in the memory, whereby the heading position of the printing medium can be corrected and altered.