Gear mechanism including gear and bearing portion having notched portion, and image forming apparatus provided with the same

A gear mechanism comprising:

• a first gear comprising a first gear body and a first rotation shaft extending in an axial direction;
• a second gear comprising a second gear body and a second rotation shaft extending in the axial direction, the second gear being capable of meshing engagement with the first gear, a force being applied to the first gear from the second gear due to the meshing engagement with the second gear;
• a first bearing portion comprising:
• a first collar portion allowing the first rotation shaft to be inserted therethrough to rotatably support the first rotation shaft;
• and
• a first notched portion allowing a portion of the first rotation shaft to be exposed to an outside, the first notched portion being formed by partially cutting away the first collar portion,
• wherein the first bearing portion has a first region and a second region opposite the first region with respect to a first imaginary plane, the first region and the second region being defined by dividing the first bearing portion by the first imaginary plane, the first imaginary plane extending in the axial direction and containing a first linear line, the first linear line passing through a center of the first rotation shaft inserted through the first collar portion and perpendicular to a direction of a line of action of the force, the first region being positioned downstream of the first linear line in the direction of the line of action of the force, and
• wherein the first notched portion is formed in the second region;
• and
• a second bearing portion comprising;
• a second collar portion allowing the second rotation shaft to be inserted therethrough to rotatably support the second rotation shaft;
• and
• a second notched portion allowing a portion of the second rotation shaft to be exposed to an outside, the second notched portion being formed by partially cutting away the second collar portion,
• wherein a second force is applied to the second gear from the first gear due to the meshing engagement with the first gear,
• wherein the second bearing portion has a third region and a fourth region opposite the third region with respect to a second imaginary plane, the third region and the fourth region being defined by dividing the second bearing portion by the second imaginary plane, the second imaginary plane extending in the axial direction and containing a second linear line different from the first linear line, the second linear line passing through a center of the second rotation shaft inserted through the second collar portion and perpendicular to a direction of a line of action of the second force, the third region being positioned down stream of the second linear line in the direction of the line of action of the second force, and
• wherein the second notched portion is formed in the fourth region.

A gear mechanism comprising:

• at least one gear comprising a gear body and a rotation shaft extending in an axial direction, the at least one gear being capable of meshing engagement with another gear, a force being applied to the at least one gear from the another gear due to the meshing engagement with the another gear;
• and
• at least one bearing portion comprising:
• a collar portion allowing the rotation shaft to be inserted therethrough to rotatably support the rotation shaft;
• and
• a notched portion allowing a portion of the rotation shaft to be exposed to an outside, the notched portion being formed by partially cutting away the collar portion,
• wherein the at least one bearing portion has a first region and a second region opposite the first region with respect to a first imaginary plane, the first region and the second region being defined by dividing the bearing portion by the first imaginary plane, the first imaginary plane extending in the axial direction and containing a first linear line, the first linear line passing through a center of the rotation shaft inserted through the collar portion and perpendicular to a direction of a line of action of the force, the first region being positioned downstream of the first linear line in the direction of the line of action of the force,
• wherein the notched portion is formed in the second region,
• wherein the at least one bearing portion has a first portion and a second portion in the axial direction, the first portion being positioned farther from the gear body in the axial direction than the second portion is from the gear body,
• wherein the notched portion is formed in the first portion, and
• wherein the second portion surrounds an entire circumference of the rotation shaft.