Matsushita Electric Industrial Co., Ltd.

Panasonic Corporation

Tomoyuki Noguchi

Masahiro Samei

Hideki Tatematsu

Kazunori Matsuo

Yukinori Hara

Tadayuki Kajiwara

Noboru Katakabe

Mitsuhide Matsuda

Masaharu Oyama

Tadashi Shiraishi

Hirofumi Ihara

Yasuhiro Nonaka

Keiichi Matsuzaki

Masaru Imai

Hideaki Horio

Youichi Nakamura

Akihiro Yamashita

Tadafumi Shimizu

Shigemitsu Tani

Masaya Shimada

Kazuhiko Soeda

Naoto Matsuo

Hirokazu Ikeda

Shinsuke Sato

Shunichi Uchinami

Naomi Uchida

Yuhzoh Kawano

Akira Sadamoto

The present invention switches to and from generation of a luminance signal based on a visible light pixel signal and generation of a luminance signal based on a near infrared light pixel signal depending on a result of comparison of signal levels of the visible light pixel signal and the near infrared light pixel signal.

Imaging device and signal processing circuit for the imaging device

A fixing device for reducing, without fail, the heating output without using a control circuit if an excessive temperature rise of a rotary heating member is predicted, even if the control circuit fails or runs away. In the fixing device, heating of a fixing belt for heat-fixing an unfixed image on a recording medium is controlled by a body-side processor. When the fixing belt stops or rotates at a rotational speed equal to or below a threshold, an oscillation stop circuit stops the oscillation of an inverter circuit to stop the heating, independently of the processor. To check the operation of a rotation detection circuit for detecting the rotating state of the fixing belt (fixing roller) and the oscillation stop circuit, self-diagnosis is utilized to ascertain that the fixing belt is not heated by giving a heating instruction when the condition of not heating the fixing belt is satisfied is performed when the power is turned on or is performed regularly during standby.

Fixing apparatus and image forming apparatus including power suppression

A heat generating roller, fixing equipment and an image forming apparatus in which warm-up time is shortened while preventing excessive temperature rise and good fixing performance is realized by preventing offset. The heat generating roller is formed principally by laying a high permeability conductive layer and a nonmagnetic conductive layer in layer. When a voltage is applied from a power supply to an exciting coil and an alternating current flow, magnetic flux is generated around the exciting coil and a magnetic field is formed. Magnetic coupling of a system including the heat generating roller and the exciting coil is advantageous at a low temperature and heat generation of the heat generating roller is accelerated. When the Curie point is exceeded, skin depth increases and skin resistance decreases, which suppresses generation of Joules heat and reduces heat generation of the heat generating roller.

Heat generating roller, fixing equipment, and image forming apparatus

An image heating apparatus that enables a temperature of an image heating element to be stably maintained at a target temperature as a fixing speed varies. A Proportional-Integral-Derivative (PID) controller determines whether a temperature control computation results in a range that allows temperature control with one IGBT, and a linear control is performed if the result is at least equal to a minimum power obtained as IH output. PWM control is performed at minimum power if the power is less than a required minimum power. Thus, a computation method of a supply power computator need not be switched according to the fixing speed, and a calorific value of a fixing belt can be controlled using one computation method.

Image heating apparatus

PID control performs integral control using an integral value of a deviation between a set temperature and current temperature. In particular, when a proportionality factor Kp is large, a fixing belt reaches a target temperature quickly but overshoot increases. On the other hand, when the proportionality factor Kp is small, the output is reduced gradually, and therefore the fixing belt reaches a target temperature slowly but the overshoot is small. Thus, a heat value control section changes the control value of the PID control according to the temperature (belt temperature) of a fixing belt at the start of heating as detected by a temperature detector. More specifically, a proportionality factor Kp of a calculation expression of the PID calculation is changed according to the belt temperature of the fixing belt. This makes it possible to reduce an overshoot when the temperature of the fixing belt increases.

Image heating apparatus including PID control

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

The present invention provides an induction heating apparatus including a fixing belt that heats an unfixed image on recording paper, an excitation coil that induction-heats the fixing belt, an inverter circuit that supplies power to the excitation coil, a harness that electrically connects the excitation coil and the inverter circuit. The harness is constructed of a litz wire having a resistance of the harness section of 0.016 &#x3a9; or below formed by stranding several tens of wires which are conductive wires coated with an insulator into a predetermined thickness.

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

Disclosed is a printer apparatus that ensures temperature control of a heat-up roller in a fixing unit thereof. An image-forming unit forms an image to be transferred onto a recording material. The fixing unit fixes the image onto the recording material. The fixing unit includes a heat-up roller, a heating section for heating the heat-up roller, a power supply section for supplying power to the heating section, and a heat controller for controlling the power supply section. The heat controller is disposed in contact with the inner circumferential surface of the heat-up roller. When heated to temperatures above a predetermined value, the heat controller is thermally deformed and leaves the inner circumferential surface of said heat-up roller to interrupt the power supply of the power supply section to the heating section.

Printer apparatus having fixing unit with heat controller for controlling temperature of heat-up roller

A printer includes, in its fixing device operable to fix toner particles onto a recording medium, a heating roller containing magnetic metal, a fixing roller disposed parallel to the heating roller, an endless belt containing magnetic metal bridged across the heating roller and the fixing roller. The printer also includes a press roller pressed to the fixing roller via the endless belt and the recording medium, and a coil core being operable to produce magnetic fields so as to cause both of the heating roller and the endless belt to generate heat with the magnetic metals contained therein.

Printer and fixing device which maintain a stable temperature for fixing a toner image

The fixing device includes a heating roller made of magnetic metal and heated by electromagnetic induction; a fixing roller disposed parallel to the heating roller; an endless toner heating medium belt bridged across the heating roller and the fixing roller, and a press roller pressed to the fixing roller via the toner heating medium. The press roller rotates in the same direction as the toner heating medium belt to form a fixing nip region, and the belt is heated by the heating roller and rotated by the two rollers. The construction of the present invention achieves stable temperature control of the toner heating medium, and provides a stable fixing quality of the toner image.

Toner image forming device with belt heated by electromagnetic induction heating

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 forms test patches with no lowering of image density and no unevenness of image density. The image forming device includes a unit for generating image data for at least one test patch, an image bearing medium on which a latent image of the test patch is formed being based upon the image data generated by the test patch generating unit, developing unit for supplying toner by means of a developing roller onto the latent image so as to manifest the latent image in order to obtain a toner image, a density sensor for detecting a toner density of a toner image in the manifested test patch, and a compensator for compensating the density, being based upon a value of an output from the density sensor. With this arrangement, the test patch generating unit is adapted to create the test patches after the toner on the developing roller is consumed by a quantity corresponding to one turn of the developing roller.

Image forming apparatus

By increasing/deceasing electric energy per unit time supplied to heat energy generation means arranged in a liquid chamber having a nozzle, the amount of the ink emitted from the nozzle can be changed to correct a difference in dot diameter which occurs nozzle by nozzle and a change in dot diameter with time and to permit gradational printing.

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Fukuoka, Japan

Tomoyuki Noguchi