Image forming apparatus and fixing device that change opening widths of air blowing openings by moving shielding members with respect to a longitudinal direction of the fixing device

An image forming apparatus comprising:

• (A) an image forming portion configured to form toner images on recording materials;
• and
• (B) a fixing unit configured to form a nip, in which a toner image is fixed by nipping and feeding a recording material, wherein said fixing unit is capable of fixing the toner image on the recording material, said fixing unit including:
• (a) an elongated heater extending in a longitudinal direction of said heater, the longitudinal direction of said heater being perpendicular to a feeding direction of the recording material;
• (b) an air blowing device configured to blow air toward one end portion and another end portion of said heater with respect to the longitudinal direction when the recording material, having a size, with respect to the longitudinal direction, that is smaller than a maximum size of the recording material that can be fixed by said fixing unit, is inserted into said fixing unit;
• (c) a first opening through which air blown from said air blowing device toward the one end portion of said heater passes;
• (d) a first shielding member configured to change an opening width of said first opening with respect to the longitudinal direction;
• (e) a second opening through which air blown from said air blowing device toward the other end portion of said heater passes;
• (f) a second shielding member configured to change an opening width of said second opening with respect to the longitudinal direction;
• (g) a first driving source configured to change the opening width of said first opening with respect to the longitudinal direction;
• (h) a second driving source different from said first driving source, and configured to change the opening width of said second opening with respect to the longitudinal direction;
• (i) a detector configured to detect temperatures of the one end portion and the other end portion of said heater;
• and
• (j) a controller configured to control, on the basis of an output of said detector and size information of the recording material, the opening widths of said first opening and said second opening, so as to correspond to widths of non-passing portions of the recording material in the nip, by moving said first shielding member and said second shielding member in the longitudinal direction, respectively, when the recording material other than the maximum size is inserted into said fixing unit.

A fixing device for fixing toner images on recording materials in a nip by nipping and feeding the recording materials in the nip, said fixing device comprising:

• an elongated heater extending in a longitudinal direction of said heater of said heater, the longitudinal direction of said heater being perpendicular to a feeding direction of a recording material;
• an air blowing device configured to blow air toward one end portion and another end portion of said heater, with respect to the longitudinal direction, when the recording material, having a size, with respect to the longitudinal direction, that is smaller than a maximum size of the recording material that can be fixed by said fixing device, is inserted into said fixing device;
• a first opening through which air blown from said air blowing device toward the one end portion of said heater passes;
• a first shielding member configured to change an opening width of said first opening with respect to the longitudinal direction;
• a second opening through which air blown from said air blowing device toward the other end portion of said heater passes;
• a second shielding member configured to change an opening width of said second opening with respect to the longitudinal direction;
• a detector configured to acquire position information relating to a position of an end portion of the recording material in the longitudinal direction, and to output the position information;
• and
• a controller configured to make the opening widths of said first opening and said second opening correspond to widths of non-passing portions of the recording material in the nip by setting a moving amount of said first shielding member in the longitudinal direction and a moving amount of said second shielding member in the longitudinal direction on the basis of a deviation amount of the end portion of the recording material obtained from the position information output by said detector when the recording material having a size other than the maximum size is inserted into said fixing device, the moving amount of said first shielding member in the longitudinal direction and the moving amount of said second shielding member in the longitudinal direction being different from each other.

A fixing device for fixing toner images on recording materials in a nip by nipping and feeding the recording materials in the nip, said fixing device comprising:

• an elongated heater extending in a longitudinal direction of said heater, the longitudinal direction of said heater being perpendicular to a feeding direction of a recording material;
• an air blowing device configured to blow air toward one end portion and another end portion of said heater, with respect to the longitudinal direction, when the recording material, having a size, with respect to the longitudinal direction, that is smaller than a maximum size of the recording material that can be fixed by said fixing device, is inserted into said fixing device;
• a first opening through which air blown from said air blowing device toward the one end portion of said heater passes;
• a first shielding member configured to change an opening width of said first opening with respect to the longitudinal direction;
• a second opening through which air blown from said air blowing device toward the other end portion of said heater passes;
• a second shielding member configured to change an opening width of said second opening with respect to the longitudinal direction;
• a first driving source configured to change the opening width of said first opening with respect to the longitudinal direction;
• a second driving source different from said first driving source, and configured to change the opening width of said second opening with respect to the longitudinal direction;
• a detector configured to detect temperatures of the one end portion and the other end portion of said heater;
• and
• a controller configured to control, on the basis of an output of said detector and size information of the recording material, the opening widths of said first opening and said second opening, wherein, when the recording material having a size other than the maximum size is inserted into said fixing device, said controller makes the opening widths of said first opening and said second opening correspond to widths of non-passing portions of the recording material in the nip by moving said first shielding member and said second shielding member in the longitudinal direction, respectively, on the basis of the output of said detector and the size information of the recording material.