Abstract: An amplifier for an active terminator for outputting a specified voltage to a bus line through a terminal resistor includes a capacitor inserted between the drive line such as a base line of an output transistor and a voltage source such as a power voltage source or a grounding line. When there is a sudden change in the voltage condition in the bus line, the capacitor can quickly react to supply a current to the output transistor.

Abstract: A laser beam printing machine according to the present invention includes a polygon mirror motor; a first control circuit which generates, in response to an error in rotation of the polygon mirror motor, a control signal which bring about the rotation of the polygon mirror motor to a target rpm and performs a PWM control; an output circuit which receives data for printing and, in response to the received data, outputs data for controlling a laser beam; a voltage controlled oscillator which generates clock pulses for determining the transmission timing of the data from the output circuit; and a second control circuit which controls, in response to the control signal, a control voltage of the voltage controlled oscillator to follow up the rotation fluctuation of the polygon mirror motor.

Abstract: Receiving a track address, an ECC selection signal generation circuit generates a selection signal. In accordance with the selection signal, a read/write circuit selects the number of bits of an ECC to be added to data. Typically, a plurality of numbers of bits are assigned to respective groups of tracks such that the number of bits becomes smaller as the group of tracks is closer to the outermost track.

Abstract: In the present invention, data with regard to passing time of respective sides of a polygon mirror when a polygon motor is in a predetermined rotating condition is stored in a memory at the respective addresses, the memory is accessed in response to the rotation of the polygon mirror and the data on the side (reflection face) performing the scan on a photo sensitive drum are successively generated while corelating with the scan, a difference between a target rotating amount under a proper standard rotation of a particular side and an actual rotating amount of the particular side is obtained time to time for respective sides of the polygon mirror, which depends on the processing accuracy of the respective sides, thereby even the polygon motor having a poor processing accuracy can be controlled at the standard rotation so that the scanning speed by the rotation is brought about to a target value like a polygon motor having a high processing accuracy.

Abstract: The silk-hat-shaped flexible external gear (13) of a silk-hat flexible meshing gear device (11) comprises a body (22), a diaphragm (23) and a boss (25). Between the main portion of the body (22) and a curved portion (222) is formed a thinned portion (221) whose thickness is about 80% that of the main portion. The thickness of the diaphragm (23) is defined to be largest at the inner edge (point A), smallest at the middle portion (point B) and slightly smaller than the largest thickness at the outer edge (point C). To make the change in thickness smooth throughout, the contour is defined by use of a group of curved lines (223, 224). Providing the thinned portion (221). and defining the thickness of the diaphragm (23) in the foregoing manner relieves stress concentration at the inner and outer edges and smooths the stress distribution. As a result, the axial length and the outer diameter can be reduced to realize a compact silk-hat flexible meshing gear device.

Abstract: A laser beam printing device for conducting the print includes a control circuit for controlling a rotation speed of a rotation mirror which reflects the laser beam to scan, an image processing circuit for outputting image information in synchronism with an origin pulse signal, and an origin sensor to receive the laser beam to generate a detection signal and to transmit the signal to the image processing circuit as the origin pulse signal. The control circuit receives the detection signal from the origin sensor as a signal for detecting the rotation speed of the rotation mirror.

Abstract: An active terminator comprises a thermal shutdown circuit. When this circuit detects a predetermined high temperature, this information is supplied to a driver, and the active terminator stops operating. The signal from the thermal shutdown circuit is also supplied to an RS latch circuit that stores information to the effect that the thermal shutdown circuit has detected high temperature, and that the active terminator has stopped operation. A computer examines the contents of this RS latch circuit so that it can be determined that the terminator has stopped operating, and communication errors can therefore be prevented by, for example, reducing the data transfer rate accordingly.

Abstract: A cup-type harmonic gear drive comprises a rigid circular spline, a cup-shaped flexspline disposed inside the circular spline and a wave generator means fitted inside the flexspline for flexing the flexspline into elliptic to engage it with the circular spline and for rotating the engagement portions to thereby produce relative rotation between the splines. The flexspline has a tube, a disc-shaped diaphragm connected integrally to the end of said tube to define the cup bottom, and a thick boss formed on the center of the diaphragm. The diaphragm has a root portion from the boss, a thickness of which is set at least about three times the minimum thickness of the diaphragm. The outer profile of the diaphragm is defined, when viewed along a plane including the axis of the flexspline, by a plurality of curves having a different curvature. These curves are arranged from one having a larger curvature from the root protion to the tube portion of the diaphragm.