Matsushita Electric Industrial Co., Ltd.

Tadayuki Kajiwara

Masahiro Samei

Hideki Tatematsu

Tomoyuki Noguchi

Masaya Shimada

Kazuhiko Soeda

Keiichi Matsuzaki

Kenji Asakura

Kazunori Matsuo

Tadafumi Shimizu

Shouichi Kitagawa

Kazunori Nakamura

Yasuhiro Nonaka

Tatsuya Yoshida

Yuichi Monda

Takumi Shimokawa

Eiji Torikai

Junichi Tanizaki

Toshihiko Mitsuse

Yoshitsugu Hayashi

Hirofumi Ihara

Takanobu Kajikawa

Hideshi Fujiki

Toshiyuki Kihara

Masanobu Narazaki

Takami Maeda

Yosuke Monji

Yoshinori Senju

Yasuhiko Isobe

Jun'ichi Tanizaki

Naomi Uchida

Yuhzoh Kawano

Akira Sadamoto

Atsushi Wakiyama

Shigehisa Fujisaki

An image fixing device that is controllable with a high degree of reliability. The image fixing device is configured with a heat generator for fixing a toner image onto a recording medium that is opposed to an induction heater. Heat is generated in the heat generator through electromagnetic induction. An inverter circuit drives the induction heater. A power controller controls a power value that is output from the inverter circuit, whose power value is calculated by a power-value calculator. A power-value sensor acquires the power value output from the power controller, and a temperature sensor senses a temperature at least at one point of the heat generator. Thus, either the power value sensed by the power-value sensor or a temperature value sensed by the temperature sensor may be used as a reference value to calculate the power value in the power-value calculator.

Image fixing controller with time/temperature control

When a temperature control does not operate, and a thermal runaway state occurs, the temperatures of a heating roller and a thermostat rise rapidly. When the rise in the temperature occurs such that the temperature of the thermostat reaches or exceeds a predetermined temperature, both ends of a thermostat are brought into an open circuit state. Thus the supply of a power from a commercial power source to an exciting coil is directly cut off.

Heat generating apparatus using electromagnetic induction

A heating device utilizing electromagnetic induction is provided with an induction heating unit that is opposed to a heating member and causes the heating member to heat through electromagnetic induction. The induction heating unit has an exciting coil for generating a magnetic field and a coil guide member on which the exciting coil is wound. The exciting coil is formed in at least two layers in such a manner that a first layer is formed on a circumferential surface of the coil guide member by winding a plurality of turns and a second layer is formed around and outside the first layer on the side opposite to the coil guide member, and winding of each of the second layer and following layers is started from a position close to a winding start position of the first layer.

Heating device and fuser utilizing electromagnetic induction

A short ring is provided outside a support frame. In the short ring, eddy current is generated in such a direction as to cancel apart of a magnetic flux developed from the exciting coil when it is fed with current, which the part of the magnetic flux leaks to outside. When the eddy current is generated, a magnetic field is developed in such a direction as to cancel the magnetic field by the leaking flux, as taught by Fleming's law. The result is that unnecessary radiation by the leaking flux is prevented, and hence noise generation in other members or devices is suppressed.

Heating device using electromagnetic induction and fuser

In a toner image forming apparatus, a contact member for pressing a work piece at a pressing position against a toner image on a movable transfer member so that the toner image is transferred from the transfer member onto the work piece is pressed against the transfer member while a test pattern toner image which is prevented from being transferred onto the work piece moves from a transfer position at which the toner image and the test pattern toner image are transferred onto the transfer member and a detecting position at which the test pattern toner image is detected to obtain a difference between the test pattern toner image on the transfer member and a desired test pattern image.

Image forming apparatus having test pattern transfer prevention control

A color-image forming apparatus minimizes displacement in toner images due to irregularities in the thickness of an inter-stage transfer belt. The pattern detector detects a registration reference pattern formed on the belt. Accepting information on displacement over one cycle of travel of the belt from the pattern detector, the displacement amount calculator detects information on displacement in a print range which the toner images formed in a plurality of image-forming stations are transferred thereto. The displacement amount calculator then calculates a mean value of displacement in the range. The central processing unit (CPU) controls the image-forming timing determined by a plurality of exposure units, according to the result calculated by the displacement amount calculator.

Color-image forming apparatus

A first image data selective output section selects odd-numbered image data of the second raster scan line from a memory section to cause a first exposure section to form an electrostatic latent image on a photoconductor drum. At the same time, a second image data selective output section selects even-numbered image data of the first raster scan line from the memory section to cause a second exposure section to form an electrostatic latent image on the photoconductor drum. In the second main scanning operation, positions of light beams are moved by an amount of one raster line in a sub-scanning direction so that the first image data selective output section forms odd-numbered image data of the third raster line and at the same time, the second image data selective output section forms even-numbered image data of the second raster line.

Image generating apparatus

A registering pattern having a predetermined configuration for each color is formed on a transfer material, and color misregistering is detected and corrected by laser beams and a photosensor.

Color image forming apparatus

An image forming apparatus has a plurality of drive motors for driving a plurality of photosensitive drums independently, a plurality of motor rotation controllers for controlling rotation and driving of the plurality of drive motors independently, a plurality of rotation phase detectors for detecting the rotation phase of each one of the plurality of photosensitive drums, a rotation phase difference calculator for calculating the rotation phase difference of the other photosensitive drums corresponding to the rotation phase of the photosensitive drum for black as the reference, a phase correction setting unit for setting the rotation phase difference in printing operation, and a phase correction controller for correcting rotation phase of the other photosensitive drums on the basis of the calculated rotation phase difference and the set rotation phase difference.

Color image forming apparatus with phase correction controller

In an image forming apparatus, even when the image forming positions of the plural light beams of the exposure optical system vary, there can be formed an image without any shifting between image forming positions. In response to a print reference signal from a timing controller, an output controller causes a storage to output image data of a first raster to a second temporary memory and image data of a second raster to a first temporary memory. The output controller supplies the second and first temporary memories with data output reference signals respectively indicating points of timing when a predetermined period of time lapses after each of the laser beams respectively of first and second exposing units enters a sensor disposed at a reference position. According to the output reference signals, the image data is outputted to the first and second exposing units such that an image is formed at timing corresponding to image forming positions of the laser beams.

Image forming apparatus for concurrent exposure of lines having variable

An image forming apparatus performs the gamma correction based on an image density on a photosensitive body or an intermediate transfer body. In the image forming apparatus, a test pattern generator unit generates a test image on the photosensitive body or the intermediate transfer body. A first density detector unit is provided in an upstream of a toner transfer section with respect to a rotation direction of the photosensitive body or the intermediate transfer body, and detects an image density on the photosensitive body or the intermediate transfer body. A second density detector unit is provided in a downstream of the toner transfer section with respect to the rotation direction of the photosensitive body or the intermediate transfer body, and detects the image density on the photosensitive body or the intermediate transfer body. A corrector unit corrects image data. A control unit calculates correction data for use in correcting the image data based on image density data outputted from the first and second density detector units to set the correction data in the corrector unit.

Gamma correction for apparatus using pre and post transfer image density

An image data producing apparatus for bit-developing processed image data includes a system processing memory and an variable capacity image data memory for storing bit-developed image data; control means is also included for changing the storage capacity of the image data memory.

Image producing apparatus with memory unit having an image memory area

An image processing apparatus includes a window setting device for setting a portion of a written region of an image composed of dots in an orthogonal matrix as a window, and for moving the set portion within the written region. A first edge detecting device serves to detect differences between image data of a given dot in the window set by the window setting device and image data of dots neighboring the given dot, and serves to detect directions of the detected differences. A second edge detecting device serves to detect edges between neighboring dots other than the given dot, the detected edges relating to image data differences and image data difference directions respectively equal to the image data differences and the image data difference directions detected by the first edge detecting device. A calculating device serves to provide the edges, detected by the second edge detecting device, with predetermined coefficients respectively, and serves to add the predetermined coefficients for the edges detected by the second edge detecting device to calculate a sum of the predetermined coefficients. A signal generating device serves to generate an image signal which varies a size of the given dot in accordance with the sum of the predetermined coefficients which is calculated by the calculating device.

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Fukuoka, Japan

Tadayuki Kajiwara