Matsushita Electric Industrial Co., Ltd.

Shoichi Kitagawa

Masahiro Samei

Keiichi Matsuzaki

Hideki Tatematsu

Kazunori Matsuo

Tadafumi Shimizu

Kenji Asakura

Masaru Imai

Yuji Toyomura

Masakazu Mizusaki

Masanobu Narazaki

The present invention relates to an image forming apparatus that enables the occurrence of print defects due to a first print start time delay to be eliminated without using a temperature sensor that has a small thermal time constant. When the temperature of a fixing belt serving as an image heating body is greater than or equal to a predetermined temperature following the elapse of a fixed time after an image forming operation is started, recording paper is transported to a nip area (fixing area) of a fixing apparatus before the temperature detected by a temperature sensor reaches a predetermined image fixing temperature, and an image forming operation is started immediately.

Method and apparatus for controlling image forming operation of an image forming apparatus

A fixing apparatus is provided that enables a recording medium that has undergone heat-fixing to be separated smoothly from a heating medium without causing a sheet jam or image disturbance. In this apparatus, there are provided on the guide surface of a separator two step parts raised along the guide surface guide width direction. Recording paper is transported gripped by a fixing nip, is guided so as to come into contact with only the apex parts of step parts, and is separated from the surface of a fixing belt. Thus, a gap is formed between the guide surface and the heat-fixing surface of recording paper guided along the guide surface, the contact area between the heat-fixing surface of recording paper and the guide surface decreases, the heat-fixing surface of recording paper becomes less prone to adhere to the guide surface of the separator, and recording paper is smoothly separated from the fixing belt without causing a sheet jam or image disturbance.

Fixing apparatus

An image heating device is operational to estimate a temperature of a pressure roller so as to determine a set temperature for a roller belt in a subsequent image heating period.

Image heating device, image forming apparatus, image copying machine, and method for controlling temperature

An image heating device is provided with reduced cost, by which a difference in glossiness among printed images on recording media is eliminated, and the wrapping of a belt and the like at a high temperature is prevented. In the image heating device, a controller estimates a temperature of a pressure roller according to at least one of a temperature of a belt detected by a temperature sensor and a variation with time in the detected temperature from completion of the heating after application of an electric power to the magnetization coil by an exciting circuit is stopped and the heating of the belt by the heating roller is stopped, so as to determine a set temperature for the belt in a subsequent image heating period.

A fixing device as an image heating device is provided, by which a difference in glossiness is not caused in a recording medium in the axial direction of a pressure roller. When a print request is issued during the end-processing sequence, an electric power applied to a magnetization coil via an exciting circuit is dropped to 0 by controlling means during the start-processing sequence, and after an appropriate interval, the heating with full power is restarted by the controlling means. By so doing, the decrease in temperature at both ends of a fixing belt and a heat-generating roller in the axial direction can be compensated.

An image reading apparatus for reading a original line by line, by moving the line image sensor in a direction orthogonal to the line, in which the line sensor is displaced in the line direction in each line to read the image of the original in a checkered pattern of pixels, and for interpolating a pixel in spaces of the said checkered pattern, plural interpolation candidate values for the pixel are determined and one of them is selected according to surrounding pixel values of the said pixel position to be interpolated, thereby reproducing edge portion of the original accurately.

Growing community of inventors

Fukuoka, Japan

Shoichi Kitagawa