Minolta Company, Ltd.

Sharp Kabushiki Kaisha Corporation

Akira Takasu

Toshikazu Higashi

Teruhiko Fujikura

Takahiro Tsujimoto

Tomonobu Tamura

Noriyuki Jinbo

Tatsuya Eguchi

Katsuhide Sakai

Hideki Matsuura

Yoshikazu Naito

Kiyohito Tsujihara

Shinya Kawanishi

Kouichi Furuta

Keiichi Okada

Ichiro Bessho

Morio Kinoshita

Rotational force of a driving motor is transferred to a photosensitive drum via a planetary-roller reduction device, so that the photosensitive drum is rotated. A speed detector set on the shaft of the photosensitive drum detects the rotational speed of the photosensitive drum. In accordance with the detected rotational speed of the photosensitive drum, the rotational speed of the driving motor is adjusted so that the photosensitive drum is rotated at a constant speed.

Rotator driving device, image forming apparatus using the rotator driving device, and method of driving rotator

An induction heating and fixing device includes a hollow cylindrical fixing member, a core for forming a closed magnetic circuit, a ring member formed of magnetic material and provided on the core in the vicinity of the bilateral ends of the fixing member, a coil wound around the core, and a pressure member disposed so as to press against the fixing member. This device suppresses temperature drop at the bilateral ends of the fixing roller and maintains uniform temperature distribution in the axial direction of the fixing roller by leaving the device open at both bilateral ends.

Induction heating and fixing device for fixing toner on a recording medium in an image forming apparatus

An optical system driving device is provided. This optical system driving device includes a driving unit for driving an optical system, and a controller for controlling the driving unit so as to create an easement interval for temporarily easing the acceleration during an acceleration period. The optical system reaches a predetermined running velocity at the end of the acceleration period.

Controlling the acceleration and deceleration of a motor with an acceleration easement interval

A luminescence controlling apparatus includes a rare gas pipe equipped with a pair of electrodes in which rare gas is sealed, a power supply for impressing voltage to the pair of electrodes and an electric charge absorption member for absorbing electrons generated during electric discharge of the rare gas pipe caused by impressing voltage to the pair of electrodes. The absorption member is disposed in the rare gas pipe. The luminescence controlling apparatus further includes a controller for controlling a luminescence amount of the rare gas pipe by adjusting a quantity of electrons absorbed by the electric charge absorption member.

Luminescence controlling apparatus, a luminescence apparatus, an image reading apparatus and an image forming apparatus

The object of the present invention is to provide an induction heating fusing device in which the rotary heating member, such as a fusing roller or fusing belt, may be easily replaced. In order to attain this objective, the induction heating fusing device has a core, which forms a closed magnetic circuit, that comprises a first core component that runs though the empty space of the fusing roller, and a second core component that exists outside the empty space of the fusing roller, said core components being separable. The fusing roller, first core component and induction coil are housed in a casing, and comprise a fusing unit that may be replaceably mounted to the main unit of an image forming apparatus. During replacement of the fusing unit, the second core component remains in the image forming apparatus. The induction heating fusing device also has a pressurization means that causes the end surfaces of the first core component and the end surfaces of the second core component to be in pressure contact.

Induction heating fusing device

Image forming apparatus

A rotational shaft of a photosensitive drum is connected to a rotational shaft of a stepping motor by a coupling, so that the stepping motor directly drives the photosensitive drum. Here, &thgr; (&deg;) indicating a step angle of the stepping motor, p (mm) indicating a distance between scanning lines on the photosensitive drum, &pgr; indicating the circular constant, and d (mm) indicating a diameter of the photosensitive drum are set so as to satisfy an equation n&middot;&thgr;&equals;(360&middot;p)/(&pgr;&middot;d) to make an optical unit scan the photosensitive drum by one scanning line every time the photosensitive drum is made to rotate n steps, n being a positive integer.

Image forming apparatus having photosensitive drum driven by stepping motor

In an image forming apparatus which forms images by transferring to a transfer drum a toner image formed on the surface of the photosensitive member directly driven by a stepping motor, the relationship between the stepping angle '.theta.' (.degree.) of the stepping motor and the rotational speed 'N' (rpm) of the photosensitive drum is expressed by the equation .theta..ltoreq.(360.times.N)/(60.times.a.times.b). Where 'a' is a natural number, optimally 10, which is less than the initial predetermined tolerance value when the harmonic content of rotational variation generated by the step period of the stepping motor is '1/a', and 'b' is the target frequency (Hz) of 100.

An apparatus and method for eliminating position deviations of a photosensitive drum which is rotated by a stepping motor driven by full step and half step drive pulses. The apparatus includes a photosensitive drum, a stepping motor which rotates the photosensitive drum; and a controller which controls the stepping motor to be driven with half step drive pulses when the photosensitive drum is being scanned. In the apparatus and method, a scanning starting control is performed by driving the stepping motor by full step drive pulses so that salient poles of the rotor are aligned with salient poles of the stator such that the rotor is in a stable position. The full step drive pulses are switched to half step drive pulses before scanning is started, and the scanning of the photosensitive drum is started on an even numbered half step drive pulse.

Method and apparatus for eliminating positional deviations of a

A drive control mechanism for an image reader having a controller, to control a drive current impressed to a connected stepping motor such that the impression of the drive current is carried out in a prescribed number of steps, and a changer, to change a largest value of a drive current in response to a scanning speed of a reading device of the image reader. Consequently, smooth rotation with little torque ripple may be obtained through microstep driving, and by changing a largest drive current, control of a drive torque becomes easier, thus making it possible to maintain an even balance between load torque and drive vibration when a high-torque motor is used to eliminate slider vibration.

Image reader

A signal processor having excellent noise resistance characteristics while maintaining superior synchronizing characteristics for hardware interrupt processes. Signal A output from a port REM of a high order CPU is input in parallel as signals B and C to an interrupt port INT of a motor drive control CPU, and to a normal input port Pi, respectively. Timers x and y are started at the same time as interrupt signal B falls, timer y counts up to time Y before time X set by timer x, and at that time a determination is made as to whether or not signal C input to port Pi and signal B input to port INT are identical. If signals B and C are identical, they are normal input signals, and pulse signals are output from ports P0-P3 after time X elapses. If signals B and C are different, a pulse signal is not output from the ports P0-P3.

Signal processor

A document reading device comprises a plurality of distance sensors, an original document size detection board, and a main unit control board. The plurality of distance sensors measure distance as for each certain position of an original document table. The original document size detection board comprises an EEPROM for storing a threshold value and an original document size detection CPU 1 for implementing a program for original document size detection. The original document size detection board judges the presence or the absence of an original document at each preset position of an original document table by comparing each threshold value from the plurality of distance sensors with the threshold value, detects the size of an original document according to the judging result from the original document size detection board, and outputs data indicative of the detected original document size. The main unit control CPU 2 implements a program for original document reading control.

Device for dtecting the size of an original document in a document reader

According to the invention, when directed to slow down a driven device, the speed of a driving motor is reduced from a first speed to a slower second speed. In this state, a driving gear continues to rotate at said second speed, whereas a driven gear continues to rotate by inertia and gradually slows down from said first speed. Thus, the rear of a cog of the driven gear is separated from the front of a cog of the driving gear. When the speed of the driven gear is equal to the second speed, i.e., the speed of the driving gear, the front of another cog of the driven gear reaches the rear of said cog of the driving gear. Accordingly, both gears lightly make contact. Thereafter, the driving motor is rapidly braked by maintaining the contact of the driving gear and driven gear such that both gears slow down and stop. When slowing down a driven device, noise generated by the impact of both gears is reduced as much as possible, and the time for slowing down a driven device is reduced.

Growing community of inventors

Toyokawa, Japan

Akira Takasu