Abstract: A non-impact printer has a print data correction circuit for providing a print data correction processing for video signals transmitted from a printing control unit to produce correction output data or patterns for printing on basic raster lines and other correction output data or patterns for printing on sub-raster lines. Those correction output data or patterns are supplied to the print head in the form of a real printing data signal.

Abstract: Bit data of a received video signal is partially converted into a first signal representing a data sequence corresponding to the resolution of an LED head. The first signal is transmitted to the LED head in the form of a real printing data signal that is to be printed on a basic raster line in synchronism with a line timing signal. The remaining bit data of the received video signal, which are not converted into the first signal, are converted into a second signal representing another data sequence, and then stored in a line buffer. The second signal stored in the line buffer is transmitted to the LED head in the form of a real printing data signal that is to be printed on an additional raster line in synchronism with an additional line timing signal. The LED head drive energy with which the basic raster lines are printed and another LED head drive energy with which the additional raster lines are printed are set independently of each other. The LED head may be provided with such a resolution function.

Abstract: A non-impact printer include a print head with a plurality of print elements such as light emitting diodes (LEDs). A driver drives the plurality of LEDs in accordance with logical states of corresponding bits of print data. A non-volatile memory stores energy specifying data. The energy specifying data describes an amount of drive energy that should be supplied to each of the plurality of print elements when each of the plurality of LEDs are driven during the printing. A random number generator generates random numbers. An adder adds the random numbers to the values of the energy specifying data to produce the energy specifying data that fluctuates within a predetermined range. Each of the plurality of LEDs is supplied with an amount of drive energy to in accordance with the fluctuating energy specifying data, thereby rendering the variations in print density of an entire image not detectable.

Abstract: A color image recording apparatus operates in a color print mode and in a monochrome printing mode. A set of color print heads are driven in accordance with corresponding color image data. A monochrome print head is driven in accordance with black image data. A controller transmits in parallel or in serial the color image data and the black image data to the corresponding print heads in a color printing mode. The controller transmits the black image data faster in the monochrome printing mode than in the color printing mode, thereby increasing printing speed. The controller may include signal processing circuits such as compressing circuits and expanding circuit for the respective color image data and black image data. In the monochrome printing mode, the controller divides the black image data into a plurality of segments and supplies the segments in parallel to the signal processing circuits.

Abstract: A non-impact printer has a print data correction circuit for providing a print data correction processing for video signals transmitted from a printing control unit to produce correction output data or pattern for printing on the basic raster line and other correction output data or patterns for printing on the sub-raster lines. Those correction output data or patterns are supplied to the print head in the form of a real printing data signal.

Abstract: An LED printer includes a printing control unit and an LED head. When a video signal received at the control unit has a higher resolution than the LED head, the control unit carries out the logical AND between successive bit data of the video signal to convert the video signal to a first signal. Corresponding to a line timing signal, this first signal is transferred as a head data signal to the LED head and is then printed on a basic raster scanning line. Further, the control unit also carries out the exclusive-OR between the successive bit data of the video signal so that the video signal is converted to a second signal and outputted to a line buffer. Corresponding to an additional line timing signal, the second signal is transferred as another head data signal to the LED head and is printed on an additional raster scanning line. The LED head drive energy for performing printing along the basic raster scanning line is set independently.

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: A toner image fixing device in an electrophotographic image forming apparatus has a heating roller containing a heater and a backup roller, a surface of which is in contact with a surface of the heating roller. A toner image on the paper is fixed by causing the paper to pass through a contacting portion of the heating roller and the backup roller. The toner image fixing device also has a driving device for supplying driving power to the heating roller or the backup roller to rotate both the heating roller and the backup roller, and a controller. The controller controls the driving section in such a way that both the heating roller and the backup roller begin to rotate intermittently immediately after an electric power supply switch of the apparatus is turned on and heat generation from the heater is initiated, and subsequently begin to rotate continuously when the backup roller achieves one revolution by the intermittent rotation.

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: Bit data of a received video signal is partially converted into a first signal representing a data sequence corresponding to the resolution of an LED head. The remaining bit data of the received video signal, which are not converted into the first signal are converted into a second signal representing another data sequence corresponding to the resolution of an LED head. The LED head includes a resolution conversion circuit which converts the video data into the first signal and the second signal. The signals are stored in a shift register having a plurality of line buffers. The first signal is printed on a basic raster line and the second signal is printed on an additional raster line. An LED head drive energy with which basic raster lines are printed and another LED head drive energy with which additional raster lines are printed are set independently of each other.

Abstract: Bit data of a received video signal is partially converted into a first signal representing a data sequence corresponding to the resolution of an LED head. The first signal is transmitted to the LED head in the form of a real printing data signal that is to be printed on a basic raster line in synchronism with a line timing signal. The remaining bit data of the received video signal, which are not converted into the first signal, are converted into a second signal representing another data sequence, and then stored in a line buffer. The second signal stored in the line buffer is transmitted to the LED head in the form of a real printing data signal that is to be printed on an additional raster line in synchronism with an additional line timing signal. The LED head drive energy with which the basic raster lines are printed and another LED head drive energy with which the additional raster lines are printed are set independently of each other. The LED head may be provided with such a resolution function.

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: Bit data of a received video signal is partially converted into a first signal representing a data sequence corresponding to the resolution of an LED head. The first signal is transmitted to the LED head in the form of a real printing data signal that is to be printed on a basic raster line in synchronism with a line timing signal. The remaining bit data of the received video signal, which are not converted into the first signal, are converted into a second signal representing another data sequence, and then stored in a line buffer. The second signal stored in the line buffer is transmitted to the LED head in the form of a real printing data signal that is to be printed on an additional raster line in synchronism with an additional line timing signal. The LED head drive energy with which the basic raster lines are printed and another LED head drive energy with which the additional raster lines are printed are set independently of each other.

Abstract: A method for printing an image including the step of generating a basic line timing signal and an additional line timing signal providing timings between respective timings of the basic line timing signal, producing a matrix by a video signal of a number of lines corresponding to a ratio of a resolution of the video signal to a resolution of a printing portion, producing one dot of a grayscale data signal having grayscale information of dots of the matrix, and driving a printing head by head drive energy determined according to the grayscale data signal, when an image is printed by using the printing head having a resolution in the raster direction less than the resolution of the video signal for forming the image to be printed. Although a number of dots for forming the image is reduced, amount of information is not reduced since dot information is converted into the grayscale information, so that high-quality printing is possible at a time of printing for grayscale.

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: In an electrophotographic printer, a power supply is connected to a transfer roller to which a current is supplied at a time that a print paper is inserted between a photosensitive drum 10 and the transfer roller. Since respective print papers have different resistances from one another, a voltage according to the kind of the print paper is generated at the transfer roller at a time that a preset current is supplied to the transfer roller, and is held. A sensor is arranged for detecting the width of the print paper, and detects the width of the print paper inserted between the photosensitive drum and the transfer roller. The value of the preset current supplied to the transfer roller 14 is changed so as to adapt to the width of the print paper.

Abstract: A multivoltage power supply which can output a plurality of high voltages in parallel. The voltage values of the respective outputs are feedback to an A/D converter. Each feedback signal is converted to a digital signal and the difference between the digital signal and a corresponding predetermined output voltage is then calculated in the form of a digital value. This digital value is inputted to a corresponding auto-reload timer, whereby a pulse signal having a pulse width corresponding to the digital value is output at a predetermined frequency.

Abstract: An electrophotographic printer capable of changing its printing speed includes a change signal generating circuit for generating a speed change signal, a head scan cycle setting circuit for setting a cycle time of a scan line of an LED array head, and a motor speed setting circuit for setting a rotation speed of a photosensitive drum. Since the head scan cycle setting circuit and the motor speed setting circuit are activated in response to the speed change signal outputted from the change signal generating circuit, the operations of the photosensitive drum and the LED array head are synchronized with each other, so that the printer can print a fine image on a recording medium. The printer control unit including those circuits also includes control circuits for controlling a constant current supplied to a transfer roller, and for controlling a temperature of fixing rollers, to avoid unevenness of printing.

Abstract: An image forming device for printing images on sheets of material includes a photosensitive member for carrying a latent image thereon, a developing roller rotatably disposed adjacent to the photosensitive member for supplying a layer of toner to the photosensitive member through rotation, and a developing blade adjustably disposed adjacent to the developing roller for regulating the thickness of the toner layer supplied to the photosensitive member. A driving circuit controllably rotates the developing roller, and a controller controls the driving circuit. The controller generates signals to control the driving circuit to reverse the rotation of the developing roller under certain conditions.

Abstract: A printing head drive circuit of a printer is mounted on the side of a carriage having a printing head attached thereto for a allowing said carriage to act as a heat sink. Hereby, no particular cooling means (heat sink, cooling fan and the like) is required for printing head drive elements. In addition, a controller and heat generating parts can be completely separated. Thus, it can be anticipated to reduce the number of parts and the cost required for assembling the whole structure as well as to improve reliability of the printing head drive circuit.