Abstract: A reference generator implemented in a MOS technology integrated circuit comprises a current mirror device having three pairs of transistors connected so as to obtain a stable voltage at the mid point of its second arm. This same generator also supplies a stable current.

Abstract: A passively clamped quasi-resonant DC link ("PCQRL") converter includes an output inverter having a plurality of switches, and a DC link between a DC power source and the output inverter. The DC link is realized by a clamp transformer having a clamp factor not higher than 1.1-1.3 and a small auxiliary inductance which is switched by a pair of auxiliary switches (driven by the same gating signal) and a pair of diodes. When the auxiliary switches are turned "ON", the DC link voltage drops to zero; and the switches of the output inverter then can be switched under zero voltage condition with no switching losses. Most of the modulation schemes, including PWM, are applicable to the DC link design.

Abstract: A photographic printing apparatus capable of printing, as an index print, an inlaid composite image having images of a plurality of frames of a film. An exposure device 10 of this printing apparatus includes an exposure controller 104 for controlling this exposure device 10 according to exposure conditions determined based on image information read from the film. The apparatus incorporates an index printer 40 for printing an inlaid composite image. An image information converter 103 is provided for producing, from the read image information, index-print image information corresponding to an image which is expected to be obtained on a photosensitive material if the material is exposed under the determined exposure conditions, and also for sending this index-print information to the index printer 40. A monitor 30 is provided for displaying the image information produced by the image information converter 103 for allowing checking thereof.

Abstract: Disclosed is an image forming apparatus which reproduces halftone by using variable area toning method. The image forming apparatus stores a reference pattern data for adjusting bias voltage of developing device. The image forming apparatus also stores density toning data used for printout. An image of the reference pattern data has a dot pattern of which the optical density is more sensitive to environmental fluctuation than that of density toning data.

Abstract: To improve the power conversion efficiency of a power circuit provided with a power-factor improvement converter and reduce the size, weight, and cost of the circuit, the power-factor improvement converter according to the invention is provided at a stage in front of the switching power circuit, in which a self-excited current resonant switching converter with a simple circuit construction is provided and the switching voltage thereof is fed back to the rectifying path via series resonant circuits so as to improve the power factor.

Abstract: A picture forming apparatus comprises a memory means for storing an inputted picture data, a picture data changing means for changing a stored data into a new picture data in order to save a recording material, and a picture printing means. The picture data changing means changes the stored picture data into a new picture data in order to save a recording material only when a saving command of a recording material is given. The new picture data includes smaller dots than the stored picture data and/or has a fewer picture dots than the stored picture dots. As a result, the new picture data enables the picture printing means to save a recording material.

Abstract: A screening system comprises at least one screen of which the phase is tone or image level dependent. This tone dependent phase shift influences the rosette structure and can be used to improve the neutral balance and color fidelity in multi-color reproduction and to minimize the visibility of such rosette structures in highlight and shadow areas.

Abstract: An image processor for improving the quality of a picture, in which block noise arises as a result of a block encoding operation, by rendering gradations between blocks contiguous. A control point determination section reads references pixels from a decoded image storage section in accordance with a block address output from a block address generating section. The control point determination section then outputs control point information. A boundary condition determination section determines vector information on the basis of the control point information. An interpolating section interpolates a pixel block using a bicubic interpolated surface, and the thus interpolated pixel block is held in a buffer. A control point comparison section determines whether the pixel block can be interpolated and outputs prohibition information. On the other hand, a pixel block output from an 8 by 8 pixel block reading section is held in another buffer.

Abstract: Here is disclosed a push-pull inverter characterized by a thin and small-sized boosting transformer improved to require a dielectric strength as low as possible and to be free from leakage current as well as noise. To realize such improvement, the boosting transformer is provided with a first secondary coil and a second secondary coil between which an impedance element such as a capacitor is connected so as to form together a serial circuit section, an output side of the first secondary coil is connected in a manner to have a same potential as a negative potential of a DC source and a load such as a fluorescent lamp is connected to the respective output sides of the first and second secondary coils.

Abstract: A power supply regulator comprising a regulated-voltage source; a buffer connected to the voltage source; and a diode connected to the output of the buffer. A bootstrap capacitor is located between the diode and the output of a power stage; and the output of the power stage is switched between a low and a high value by a digital signal also supplied to the input of the buffer which therefore generates a switched regulated output voltage varying between a first value equal to the regulated voltage and a second lower value. The switched regulated voltage switches from the first to the second value before the output of the power stage switches to high, thus immediately disabling the diode and preventing current spikes due to minority carriers in the diode from being transmitted to the regulated-voltage source.

Abstract: A power supply system for detecting an operating configuration of a device, such as a processor, and for providing a corresponding operating voltage to the device. The power supply system includes a configurable power supply receiving configuration signals and for providing an operating voltage having a level corresponding to the configuration signals. A frequency determination circuit, such as a speed jumper block, is provided for asserting a signal indicative of the operating frequency of the device. Also, a device configuration circuit receives a signal indicative of the operating frequency and also receives a signal indicative of a plane configuration of the device, and correspondingly asserts the configuration signals to correspond to one of a matrix or plurality of predetermined operating voltage levels.

Abstract: A power converter protective apparatus for protecting an AC-DC converter against an excess fault current by preventing the fault current of a power system from flowing into the AC-DC converter. The protective apparatus comprises a series transformer, whose primary winding is connected in series with a power system and whose secondary winding is connected to a voltage-type AC-DC converter, first current bypass means of a normally open-type connected in parallel with the primary winding, a current transformer for detecting a fault current in the power system, and a control unit for outputting a bypass control signal to the first current bypass means when the current transformer detects the fault current, whereby when the fault in the power system is detected, a fault current flowing through the primary winding is bypassed by the first current bypass means.

Abstract: An improved bridge rectifier for an alternating current generator includes a first heat sink having a first diode, and an insulating layer disposed on the first heat sink. In addition, the improved bridge rectifier includes a second heat sink disposed on the insulating layer. The second heat sink includes a base section including first and second areas, a second diode, and a diode receiving holes in the base section and receiving the second diode therein. The second heat sink also includes a plateau section disposed on the first area of the base section, and air passages disposed in and extending through the base and plateau sections. The improved bridge rectifier further includes connectors, connecting the first heat sink and the second heat sink together with the insulating layer disposed therebetween, a cover connected to the base section and covering the second area of the base section, and a capacitor connected to the cover and to the second heat sink.

Abstract: A method and apparatus for controlling a regenerative drive having line and load converters connected by a DC link, the load converter for connection to an AC machine, and the line converter for connection to an AC source/sink by means of line reactors, the drive for causing real power to flow in the line reactors to control the DC link voltage at a selected DC voltage and for determining when a commanded line converter voltage exceeds a selected maximum line converter voltage for also causing reactive power to flow in the line reactors to reduce the line converter voltage required to control the real power flow.

Abstract: A screening system comprises at least one screen of which the phase is tone or image level dependent. This tone dependent phase shift influences the rosette structure and can be used to improve the neutral balance and colour fidelity in multi-colour reproduction and to minimise the visibility of such rosette structures in highlight and shadow areas.

Abstract: An image reading apparatus disclosed in this invention has first and second line sensors. The output from the first line sensor is compressed by a first compression circuit, and the output from the second line sensor is compressed by a second compression circuit. Furthermore, control is made to output image data for one page compressed by the first compression circuit, and thereafter, to output image data for one page compressed by the second compression circuit. The first compression circuit can operate at a higher speed than the second compression circuit.

Abstract: Multiple controllers connected in parallel to control external circuits such as dc-dc converters so that the external circuits supply power equally to a load such as a microprocessor. All of the controllers are connected and each controller includes an oscillator and a pulse width modulation circuit to synchronize the frequency of all of the oscillators such that the duty cycle of all the oscillators are equal. Each controller includes an over-current protection circuit and an over-voltage protection circuit which will cause the controller with a fault to discontinue supplying power to the load. Each controller further includes a circuit to adjust the duty cycle of the non-faulty controllers when a controller with a fault is caused to discontinue supplying power to the load.

Abstract: A power supply circuit, using direct current or rectified alternating current sources having output and return supply lines (a, b), for a coil of an electromagnet having at least one principal winding (B1) and a secondary winding (B2). The power supply circuit includes a first semiconductor element (T2) having a gate and a source drain path and capable of providing or blocking a supply of current to the secondary winding (B2), the source drain path connected between the secondary winding (B2) and the return supply line (b); and a switching means (10) connected between the primary winding (B1) and the gate of the first semiconductor element (T2).

Abstract: An image copying system is disclosed which has a thermal head energized at a strobe current supply time rate corresponding to a current head temperature according to a preset strobe current supply time rate control characteristics. In copying operation at a standard speed, a read sensor 211 reads an image by performing N main scans in one sub scan. A signal processor 221 validates the image signal thus read once every N scans according to a selection signal from a mode control circuit 401. A record circuit 311 having a thermal head performs one main scan every sub scan. During a copying operation at a speed N times the standard speed, the sub scan speed is made N times and the read sensor 211 reads the image by performing one main scan every sub scan and the signal processor 221 makes the read image signal always valid by the selection signal. The record device 311 performs one main scan every sub scan. A single A/D converter is used for A/D converting head temperature as well as other output signal.

Abstract: Disclosed is an image data processor for processing input image data representing the gray level of each of pixels constituting an image to produce output image data representing the gray level of each of pixels constituting an output image. The relative position of the pixel corresponding to the input image data in a group of pixels including a predetermined number of pixels is identified. The input image data is subjected to data processing corresponding to the relative position of the pixel in the group of pixels on the basis of the result of the identification. Consequently, gray levels are represented by the entire group of pixels.