Electrophotographic apparatus having two fixing sections and control means for controlling temperature adjustments selectively to the fixing sections

An electrophotographic apparatus comprising:

• fixing means having a first through third fixing rollers for forming a first fixing section by contacting the first and second fixing rollers as well as forming a second fixing section by contacting the second and third fixing rollers, the first fixing section being temperature-adjusted in relation to a first copying mode, the second fixing section being temperature-adjusted in relation to a second copying mode;
• first through third heating means for heating the first through third fixing rollers by applying electric power;
• and
• control means which controls the electric power in such a manner that electric power is applied to the first and second or the second and third heating means for a pair of fixing rollers constituting either one of the first and second fixing sections, and after the temperatures of the pair of the fixing rollers have exceeded respective preset temperatures, electric power is preferentially applied to the first or the third heating means, while maintaining the pair of the fixing rollers at the preset temperature by controlling electric power to be applied to the first and second or the second and third heating means for the pair of the fixing rollers constituting the relevant fixing section.

An electrophotographic apparatus comprising:

• fixing means having a first through third fixing rollers for forming a first fixing section by contacting the first and second fixing rollers as well as forming a second fixing section by contacting the second and third fixing rollers, the first fixing section being temperature-adjusted in relation to a first copying mode, the second fixing section being temperature-adjusted in relation to a second copying mode;
• fixing-section forming means for allowing on demand the contact and the separation between either pair of the fixing rollers, which form the first and second fixing sections respectively;
• and
• control means for controlling the fixing-section forming means in such a manner that upon applying temperature adjustments to the first through third fixing rollers, either the first or third fixing roller, whose set temperature has a smaller difference from the set temperature of the second fixing roller, is pressed against the second fixing roller.

An electrophotographic apparatus comprising:

• fixing means having a first through third fixing rollers for forming a first fixing section by contacting the first and second fixing rollers as well as forming a second fixing section by contacting the second and third fixing rollers, the first fixing section being temperature-adjusted in relation to a first copying mode, the second fixing section being temperature-adjusted in relation to a second copying mode;
• temperature adjusting means for applying temperature adjustments to the first and second fixing sections;
• and
• control means for controlling the temperature adjusting means in such a manner that after completion of an image forming operation by the use of either of the first and second fixing sections, the temperature adjusting means continues to conduct temperature adjustments on the same fixing section during a stand-by state until the next image forming operation is called for.

An electrophotographic apparatus comprising:

• fixing means having a first through third fixing rollers for forming a first fixing section by contacting the first and second fixing rollers as well as forming a second fixing section by contacting the second and third fixing rollers, the first fixing section being temperature-adjusted in relation to a first copying mode, the second fixing section being temperature-adjusted in relation to a second copying mode;
• temperature adjusting means for applying temperature adjustments to the first and second fixing sections;
• and
• control means for controlling the temperature adjusting means in such a manner that, after completion of a copying operation using either of the first and second fixing sections, during a stand-by state before having a demand for the next image forming operation, the temperature adjusting means preferentially conducts temperature adjustments with respect to one of the fixing sections that has been used more times than the other fixing section in the number of image forming operations that have been executed up to the preceding operation.

An electrophotographic apparatus comprising:

• fixing means having a first through third fixing rollers for forming a first fixing section by contacting the first and second fixing rollers as well as forming a second fixing section by contacting the second and third fixing rollers, the first fixing section being temperature-adjusted in relation to a first copying mode, the second fixing section being temperature-adjusted in relation to a second copying mode;
• control means for providing temperature adjustments in such a manner that fixing rollers constituting either of the upper and lower fixing sections are heated;
• when the temperatures of the fixing rollers have exceeded respective predetermined temperatures, the heating operation of the fixing rollers are stopped;
• and during a period of time when the temperatures of the fixing rollers are kept above the predetermined temperatures, temperature adjustments are applied to the rest of the first through third fixing rollers.