Canon Kabushiki Kaisha

Daizo Fukuzawa

Mahito Yoshioka

Yasuhiro Shimura

Akira Kato

Yasumasa Ohtsuka

Noriaki Sato

Munehito Kurata

Akira Hayakawa

Kuniaki Kasuga

Yohji Tomoyuki

Kouichi Okuda

Shunji Nakamura

Tooru Imaizumi

Atsuyoshi Abe

Manabu Takano

Atsushi Iwasaki

Hisashi Nakahara

Hiromitsu Kumada

Yasumasa Otsuka

Tomonori Sato

Hiroyuki Kadowaki

Atsunobu Mori

Toshifumi Kitamura

Satoru Koyama

Hidenobu Suzuki

Yoshimichi Ikeda

Ken Nakagawa

Toru Imaizumi

Kenichi Ogawa

Masahide Hirai

Takashi Soya

Teruhiko Namiki

Eihiro Sakaki

Kenji Takagi

Tatsunori Ishiyama

Hiroyuki Oba

Takashi Shibuya

Toshio Yoshimoto

Yoji Tomoyuki

Yoshiyuki Yamazaki

Koichi Otaka

Tomoko Nanbu

Nobuya Tamura

An image forming apparatus, including: a determining portion to acquire a density value for respective colors of toners, obtain a sum value of the density values of the colors of the toners, obtain a numerical value indicating the number of the density values being values larger than 0 out of the density values corresponding to the colors of the toners, and determine a target temperature on the basis of the sum value and the numerical value, wherein in a case the sum value is a first value and the numerical value is a first number, the determining portion determines a first temperature as the target temperature, in a case the sum value is the first value and the numerical value is a second number that is larger than the first number, the determining portion determines a second temperature that is lower than the first temperature as the target temperature.

Image forming apparatus and image forming method

A fixing apparatus a tubular film, a nip forming member that contacts an inner surface of the film, and a roller that forms a nip portion together with the nip forming member via the film. The nip portion is an area where the film and the roller are in contact with each other and where a recording material is conveyed. The nip forming member has a protruding portion, protruding toward the roller and extending in a generatrix direction, that is provided on at least one of an upstream side and a downstream side in the nip in a conveying direction of the recording material. In the conveying direction of the recording material, an end portion of the protruding portion in the generatrix direction is arranged at a location different from a central portion of the protruding portion in the generatrix direction.

Fixing apparatus

A fixing apparatus includes a nip forming member that contacts an inner surface of a tubular film and forms a nip together with a roller via the film. The roller has a region where a diameter of the roller gradually increases in a direction from a center to each of ends of the roller with respect to a generatrix direction of the film. The nip forming member has a protruding portion, protruding toward the roller and extending in the generatrix direction, that is provided on at least one of an upstream side and a downstream side in the nip in a conveying direction of the recording material. Ends of the protruding portion in the generatrix direction are positioned at a larger distance from a center of the nip in the conveying direction than a central of the protruding portion in the generatrix direction.

A fixing apparatus includes: two rotatable members, for forming a nip, including a region where an outer diameter is increased from a longitudinal central portion toward a longitudinal end portion; a heater; and a controller for controlling a heat generation distribution of the heater. The controller is capable of controlling the heater so that the heat generation distribution of the heater is such that a heat generation amount at the longitudinal end portion is larger than that at the longitudinal central portion in a period from start of the heater until the recording material reaches the nip. A ratio of the heat generation amount at the longitudinal end portion to that at the longitudinal central portion is larger when a cumulative amount of use of the fixing apparatus is larger than a predetermined amount than when the cumulative amount of use is smaller than the predetermined amount.

Adjusting the start timing for conveying a printing material from a printing material conveying unit based on a power supply update period for power supplied to a heater allows proper power correction timing to be attained for compensating for a drop in temperature of the endless belt following the printing material entering a fixing nip portion.

Image forming apparatus controlling power supplied to fixing unit

The image forming apparatus includes a fixing portion, a temperature detection element, and a power control portion. The power control portion is capable of setting a first power supply control mode for supplying power according to the detected temperature for each one control cycle, a second power supply control mode for supplying power according to the detected temperature for each one control cycle and a third power supply control mode for supplying predetermined power, and switches, immediately before a leading edge of the recording material enters the fixing portion, a state of supplying the power in the first power supply control mode to a state of supplying the power in the second power supply control mode, and then switches the state of supplying the power in the second power supply control mode to a state of supplying the power in the third power supply control mode.

Image forming apparatus

Corrected power for compensating for a reduction in the temperature of an endless belt that accompanies the entry of a recording material into a fixing nip portion is adjusted by correcting the power supplied to a fixing unit when the recording material enters the fixing unit with a correction power based on the difference between the update time of a power updating period and the time of the entry of the recording material.

Image forming apparatus having fixing unit for fixing unfixed toner image formed on recording material onto recording material by heat

The present invention provides an image forming apparatus including an upstream conveying portion, a downstream conveying portion, and a loop detector, wherein the image forming apparatus further includes a driving portion which moves the contact portion to a projecting position where the sheet conveying path is in contact with a conveyed sheet and to a retracted position where the sheet conveying path is not in contact with the conveyed sheet, and a controlling portion which controls the driving portion such that the contact portion is moved from the projecting position to the retracted position before a tip end of a sheet which enters the sheet conveying path from the upstream conveying portion reaches the contact portion.

Image forming apparatus with conveying portions having a loop detector with contact portion for contacting the sheet

The image forming apparatus includes an image forming portion forming a toner image on a recording material, and a fixing portion heating and fixing the toner image formed on the recording material to the recording material, wherein the apparatus has a cleaning mode in which the fixing portion is cleaned, and when the cleaning mode is set, the image forming portion forms a predetermined toner image on the recording material, and the fixing portion then heats and fixes the predetermined toner image to the recording material to form a cleaning sheet which is heated and conveyed to clean the fixing portion. By the virtue of the present invention, it achieves high cleaning performance in which the fixing portion is cleaned by the cleaning sheet.

Image forming apparatus operable in a mode for cleaning a fixing portion

The image forming apparatus, in the case where image forming is performed on a recording medium whose size covers a position of a second temperature detection element perpendicularly disposed to the recording medium conveyance direction, when the detected temperature rises to a predetermined temperature during execution of the first power supply control, a first power supply control is switched to a second power supply control. In the case where image forming is performed on a recording medium whose size does not cover a position of the second temperature detection element, when the detected temperature rises to a predetermined temperature during execution of the first power supply control, a conveyance control portion executes a control for extending the conveyance interval of the recording medium. Thus, an unduly large temperature rise in the non-sheet passing portion is prevented, and a good quality image can be provided without glossy unevenness in one sheet.

Image forming apparatus with cleaning mode

The image forming apparatus includes a current detection circuit for detecting an input current from the commercial power supply to the apparatus, in which: when a current detected by the current detection circuit exceeds a predetermined value, a maximum current suppliable to a fixing portion is restricted; and when a temperature of the fixing portion falls below, in a situation where the maximum current suppliable to the fixing portion is restricted, the predetermined temperature lower than a control target temperature, a conveyance interval of a recording material conveyed to the fixing portion is extended. In the image forming apparatus, even when a consumption current of the image forming apparatus is increased during successive image formation, it is capable of controlling the consumption current so as not to exceed a maximum current of a commercial power supply, securing desired fixability, and minimizing decline of image forming performance.

Image forming apparatus for fixing an image on a recording material and a current detection circuit therefor

The image heating apparatus for heating an image formed on a recording material includes a flexible sleeve member, a guide member, a regulating member having a flange portion and a sliding portion, a rotatable member, a nip portion and a plurality of ribs. The plurality of ribs are positioned in the manner the contour of the plurality of ribs is positioned inside the contour of the sliding portion of the regulating member along the longitudinal direction of the image heating apparatus. Thereby, a reduction in the durability of the flexible sleeve member can be suppressed.

Image heating apparatus having a flexible sleeve

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Mishima, Japan

Daizo Fukuzawa