Image forming apparatus

An image forming apparatus comprising:

• an image heating member configured to heat an image formed on each of a plurality of first recording materials and a second recording material having a thickness larger than that of the first recording materials;
• a pressing member configured to form a nip, between itself and said image heating member, in which each recording material is to be nipped and conveyed;
• and
• an executing portion configured to execute different image heating conditions during the heating of the first recording materials when the image formed on the second recording material is to be subsequently formed on the first recording materials, wherein the executing portion also is configured to execute an operation in a first mode in which the image formed on each of the plurality of the first recording materials is heated under a first image heating condition and an operation in a second mode in which the image formed on the second recording material is heated under a second image heating condition,
• wherein when the image is formed in the second mode and subsequently the images are formed in the first mode, a switching operation is carried out in which the first recording material is heated under a third image heating condition different from the first image heating condition, said switching operation being started after the operation in the second mode or is started on or after the start of the operation in the first mode so that the heating of images on the first recording materials is performed under different image heating conditions when the image formed on the second recording material is to be subsequently formed on the first recording materials, and
• wherein the first and third image heating conditions comprise a sheet passing speed of the first recording materials, and wherein the sheet passing speed of the third condition is higher than the sheet passing speed of the first condition, so that the sheet passing speed of the first recording materials in the first mode is increased when the image formed on the second recording material is to be subsequently formed on the first recording material.

A fixing apparatus comprising:

• first and second rotatable members configured to fix a toner image on a sheet at a nip portion therebetween;
• a rotating mechanism configured to rotate said first and said second rotatable members;
• a pressing mechanism configured to press between said first rotatable member and said second rotatable member to form the nip portion;
• and
• a control portion configured to control an operation of said rotating mechanism and said pressing mechanism,
• wherein in the case where continuous fixing operations for plural thick sheets are subsequently performed after continuous fixing operations for plural thin sheets, thinner than the thick sheets, said control portion increases the rotational speed with which said rotating mechanism rotates said first and said second rotatable members and increases a pressure in the nip portion by said pressing mechanism during a fixing operation for the last thin sheet of the thin sheets.

A fixing apparatus comprising:

• first and second rotatable members configured to fix a toner image on a sheet at a nip portion therebetween;
• a rotating mechanism configured to rotate said first and said second rotatable members at a predetermined fixing speed;
• a pressing mechanism configured to press between said first rotatable member and said second rotatable member to form the nip portion;
• and
• a control portion configured to control an operation of said rotating mechanism and said pressing mechanism,
• wherein in the case where continuous fixing operations for plural thick sheets under a first pressure in the nip portion and a first fixing speed are subsequently performed after continuous fixing operations for plural thin sheets, thinner than the thick sheets, under a second pressure which is higher than the first pressure in the nip portion and the first fixing speed, said control portion increases the first fixing speed to a second fixing speed, which is higher than the first fixing speed, by controlling said rotating mechanism and increases the first pressure to the second pressure by controlling said pressing mechanism during a fixing operation for the last thin sheet of the thin sheets.

A fixing apparatus comprising:

• first and second rotatable members configured to fix a toner image on a sheet at a nip portion therebetween;
• a rotating mechanism configured to rotate said first and said second rotatable members at a predetermined fixing speed;
• a pressing mechanism configured to press between said first rotatable member and said second rotatable member to form the nip portion;
• and
• a control portion configured to control an operation of said rotating mechanism and said pressing mechanism,
• wherein in the case where continuous fixing operations for plural thick sheets under a first pressure in the nip portion and a first fixing speed are subsequently performed after continuous fixing operations for plural thin sheets, thinner than the thick sheets, under a second pressure which is higher than the first pressure in the nip portion and the first fixing speed, said control portion increases the first fixing speed to a second fixing speed, which is higher than the first fixing speed, by controlling said rotating mechanism and increases the first pressure to a third pressure, which is higher than the first pressure and is lower than the second pressure, by controlling said pressing mechanism during a fixing operation for the last thin sheet of the thin sheets.