Abstract: A common data line serially connects a first dot memory group and a second dot memory group in layout order of driven devices so as to form each pair. First word lines are connected to the first dot memory group. Second word lines are connected to the second dot memory group. A data writing section supplies the correction values for the first dot memory group and the correction values for the second dot memory group while shifting the timing and supplies writing signals to the first word lines and the second word lines at predetermined timing. A chip area is reduced and costs of a driving apparatus is reduced.

Abstract: An array of three-terminal switching elements such as light-emitting thyristors is formed from a thin semiconductor film. A combined semiconductor device may be formed by bonding the thin-film three-terminal switching elements to a major surface or edge surface of an integrated circuit chip including a shift register that shifts data supplied to the control electrodes of the three-terminal switching elements, or by bonding both the thin-film three-terminal switching elements and another thin semiconductor film including the shift register to a substrate. In either case, thin-film wiring may be used to interconnect the shift register and the switching elements, and the need for an array of large transistors to feed driving current to the switching elements is eliminated, reducing the size and cost of the combined semiconductor device, which can be advantageously used in the optical head of an electrophotographic printer.

Abstract: Each of a plurality of driver circuits includes a first 3-terminal switch element, a second 3-terminal switch element, and a 3-terminal light emitting element driven by the first 3-terminal switch element. The first 3-terminal switch element in a first circuit of adjacent driver circuits is driven by one of first and second clocks and the first 3-terminal switch element in a second circuit of the adjacent driver circuits is driven by the other of the first and second clocks. The second 3-terminal switch element in the first circuit supplies a signal to the second driver circuit, the signal representing an operational state of the first circuit. The second 3-terminal switch element in the first circuit includes a control electrode to which a third clock is supplied. The second 3-terminal switch element in the second circuit includes a control electrode to which a fourth clock is supplied.

Abstract: When correction data is set, a CPU 3 reads out the correction data from an EEPROM 8 through strobe signal lines STB1-N to STB4-N and supplies it as print data signals DATA3 to DATA0 to an LED driver IC 6. When the driving of an LED array 7 according to print data is instructed, the CPU 3 supplies a group selection signal to the LED array 7 through the strobe signal lines STB1-N to STB4-N. An electrophotographic printer which can realize a high speed of the operation and contribute to the improvement of the reliability is provided.

Abstract: A driving circuit includes an array of driving elements that selectively supply current from a power supply to an array of driven elements at a rate responsive to the difference between a control voltage and the power supply voltage. The control voltage is furnished to the driving elements through a conductive member that extends parallel to the array of driving elements. The driving circuit includes means for adjusting the control voltage independently at each end of the conductive member, to reduce variations in the current supplied by different driving elements.

Abstract: A dot-matrix image-forming device such as an electrophotographic printer alters the size of a dot according to the surrounding dot pattern, thereby compensating for the tendency of isolated dots or small groups of dots to be undersized due to characteristics of the image formation process. Alternatively, the device may add dots to or delete dots from a contiguous group of dots to achieve substantially the same effect. Preferably, the device both adds or deletes dots and alters the dot size. This compensation scheme enables the total area occupied by dots in a given image region to be proportional to the number of dots in the region, regardless of the dot density and arrangement in the region.

Abstract: A drive circuit drives a plurality of light emitting diodes (LED) in an LED array chip. The drive circuit includes a row of drive transistors that supply drive currents to corresponding LEDs, a control circuit that produces a control voltage for driving the drive devices, and a supply voltage electrode that extends along the row. The control circuit has a reference current transistor through which a predetermined reference current flows in accordance with a control voltage applied to the reference current transistor. The control voltage is also supplied to the individual drive devices to cause the drive currents to flow through the corresponding LEDs in reference to the reference current. The supply voltage electrode supplies a supply voltage to each of the drive transistors such that each drive transistor receives its supply voltage from a nearest location on the supply voltage electrode. The reference transistor receives its supply voltage from a substantially mid point of the supply voltage electrode.

Abstract: A print head includes a driving circuit having a cascaded series of driver integrated circuits mounted on a printed wiring board. Differential clock signals are supplied to the driver integrated circuits to synchronize the transfer of print data through the cascaded series. Even-numbered driver integrated circuits and odd-numbered driver integrated circuits are connected differently to the clock signal lines, but the even-numbered (or odd-numbered) driver integrated circuits generate an inverted internal clock signal, thereby compensating for the difference. This enables the clock signal lines to be mutually adjacent and to have a weaving layout that yields improved noise immunity.

Abstract: Adjustment of correction data for the respective LEDs at the end of manufacture of a print head is performed by transferring provisional correction data from a manufacturing device to an LED driver, directly, i.e., without once being stored in a storage circuit 10c in the print head, and measuring the amounts of light from the LEDs and varying the correction data, and repeating such an operation until the correction data is optimized. The optimized correction data as well as the strobe time data determined from the measured average power are written in the storage circuit 10c. During use of the printer, the data stored in the storage circuit 10c is used for correction of the data and determination of the strobe time.

Abstract: A driving circuit includes an array of driving elements that selectively supply current from a power supply to an array of driven elements at a rate responsive to the difference between a control voltage and the power supply voltage. The control voltage is furnished to the driving elements through a conductive member that extends parallel to the array of driving elements. The driving circuit includes means for adjusting the control voltage independently at each end of the conductive member, to reduce variations in the current supplied by different driving elements.

Abstract: A dot-matrix image-forming device such as an electrophotographic printer alters the size of a dot according to the surrounding dot pattern, thereby compensating for the tendency of isolated dots or small groups of dots to be undersized due to characteristics of the image formation process. Alternatively, the device may add dots to or delete dots from a contiguous group of dots to achieve substantially the same effect. Preferably, the device both adds or deletes dots and alters the dot size. This compensation scheme enables the total area occupied by dots in a given image region to be proportional to the number of dots in the region, regardless of the dot density and arrangement in the region.

Abstract: In a first aspect of the invention, a driven element is driven by a static driving element coupled in series with a switching element. The static driving element sets the driving current value. In a second aspect, a plurality of driven elements are driven by respective driving elements, which in turn are driven by respective pre-stage circuits, using a control voltage supplied by a single control-voltage generating circuit. Resistors inserted between the driving elements and pre-stage circuits limit transient current flow to a value within the output capability of the control-voltage generating circuit. In a third aspect, the pre-stage circuits have constant-current output characteristics, and the control-voltage generating circuit is designed to provide the necessary transient current, even when all driven elements are driven simultaneously.

Abstract: A driving circuit generates an internal control voltage that controls the driving current supplied to a group of driven elements in a printer or other device. Generation of the control voltage involves the flow of current on one or more static current paths. The driving circuit includes switching elements that open these static current paths in response to a standby command, to reduce standby power consumption of the printer or other device, and to enable quiescent-current testing of the driving circuit. The standby command may be given by a combination of signals that are also used for other purposes.

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: When correction data is set, a CPU 3 reads out the correction data from an EEPROM 8 through strobe signal lines STB1-N to STB4-N and supplies it as print data signals DATA3 to DATA0 to an LED driver IC 6. When the driving of an LED array 7 according to print data is instructed, the CPU 3 supplies a group selection signal to the LED array 7 through the strobe signal lines STB1-N to STB4-N. An electrophotographic printer which can realize a high speed of the operation and contribute to the improvement of the reliability is provided.

Abstract: A print head includes a driving circuit having a cascaded series of driver integrated circuits mounted on a printed wiring board. Differential clock signals are supplied to the driver integrated circuits to synchronize the transfer of print data through the cascaded series. Even-numbered driver integrated circuits and odd-numbered driver integrated circuits are connected differently to the clock signal lines, but the even-numbered (or odd-numbered) driver integrated circuits generate an inverted internal clock signal, thereby compensating for the difference. This enables the clock signal lines to be mutually adjacent and to have a weaving layout that yields improved noise immunity.

Abstract: A chip module includes a driver IC chip and a driven IC mounted on the drive IC by the use of anisotropic film. The driver IC has a plurality of drive-elements that drive driven-elements in the driven IC chip. A plurality of drive-elements are aligned at predetermined intervals. A power-supplying electrode extends along the plurality of drive-elements and distributes electric power to individual drive-elements. A plurality of power supplying electrode pads are provided on the power-supplying electrode. The power-supplying electrode pads receive electric power from outside and supply the electric power to the power-supplying electrode. The n-th power-supplying electrode pad is positioned at a location given by L(2n−1)/2N where N is a number of the power-supplying electrode pads, n is an integer from 1 to N, and L is a total length of the power-supplying electrode. There are provided a plurality of drive electrode pads through which the drive-elements are connected to the driven elements.

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: A temperature-sensing circuit has a pair of bipolar transistors of different sizes, exposed to the temperature to be sensed. A current mirror circuit, or an operational amplifier and another bipolar transistor, is used to sense the difference between the base-emitter voltages of the bipolar transistors and generate a corresponding output current, which is converted to a voltage output signal. This temperature-sensing circuit can be integrated into a driving circuit to sense the temperature of the driven elements and compensate for temperature effects. In a printer, the temperature-sensing circuit can be used for temperature compensation of dot-forming elements.

Abstract: A driving apparatus has driving circuits that supply driving energy to driven elements which form dots. The driving circuits are controlled by driving data indicating which driven elements are to be driven, and compensation data adjusting the amount of driving energy. The compensation data are stored in compensation memory circuits coupled to the driving circuits. A single data transfer means transfers the driving data to the driving circuits and the compensation data to the compensation memory circuits. If the driven elements are located on two or more different semiconductor chips, some of the compensation data preferably compensate for chip-to-chip differences, while other compensation data compensate for dot-to-dot differences within the same chip.