Optical scanner, optical-path adjustment method, and image forming apparatus

An optical scanner which irradiates a light beam to a scanned surface of an image support to form an electrostatic latent image on the image support surface, comprising:

• a light source emitting a light beam;
• at least one reflection mirror having a reflection surface;
• an optical element adjusting a position of a scanning line in a sub-scanning correspondence direction, the optical element having a beam-incidence surface, a first axis parallel to the main-scanning correspondence direction on the beam-incidence surface, and a second axis perpendicular to the first axis and along a beam-incidence direction;
• a first supporting unit supporting a portion of said at least one reflection mirror;
• a first adjustment unit provided to rotate said at least one reflection mirror about the first supporting unit in a direction perpendicular to the reflection surface and change a distance between the reflection surface and the image support surface in order to attain uniformity of a scanning speed of the optical scanner in the sub-scanning correspondence direction;
• a second supporting unit supporting a portion of said optical element;
• and
• a second adjustment unit provided to rotate said optical element about the second supporting unit in a direction of the second axis in order to correct an inclination of the scanning line in the sub-scanning correspondence direction to a desired position of the scanning line.

An optical-path adjustment method for an optical scanner which irradiates a light beam to a scanned surface of an image support to form an electrostatic latent image on the image support surface, the optical scanner including:

• a light source emitting a light beam;
• at least one reflection mirror having a reflection surface, a first axis parallel to a main-scanning correspondence direction on the reflection surface, and a second axis along the reflection surface and perpendicular to the first axis;
• and an optical element adjusting a position of a scanning line in a sub-scanning correspondence direction, the optical element having a beam-incidence surface, a third axis parallel to the main-scanning correspondence direction on the beam-incidence surface, and a fourth axis perpendicular to the third axis and along a beam-incidence direction, the method comprising the steps of:
• rotating said at least one reflection mirror around the second axis in order to attain uniformity of a scanning speed of the optical scanner in the sub-scanning correspondence direction;
• and
• rotating said optical element around the fourth axis in order to correct an inclination of the scanning line in the sub-scanning correspondence direction to a desired position of the scanning line,
• wherein the second rotating step is performed after the first rotating step is performed.

An optical-path adjustment method for an optical scanner which irradiates a light beam to a scanned surface of an image support to form an electrostatic latent image on the image support surface, the optical scanner including:

• a light source emitting a light beam;
• at least one reflection mirror having a reflection surface;
• an optical element adjusting a position of a scanning line in a sub-scanning correspondence direction, the optical element having a beam-incidence surface, a first axis parallel to the main-scanning correspondence direction on the beam-incidence surface, and a second axis perpendicular to the first axis and along a beam-incidence direction;
• a first supporting unit supporting a portion of said at least one reflection mirror;
• and a second supporting unit supporting a portion of said optical element, the method comprising the steps of:
• rotating said at least one reflection mirror about the first supporting unit in a direction perpendicular to the reflection surface and changing a distance between the reflection surface and the image support surface in order to attain uniformity of a scanning speed of the optical scanner in the sub-scanning correspondence direction;
• and
• rotating said optical element about the second supporting unit in a direction of the second axis in order to correct an inclination of the scanning line in the sub-scanning correspondence direction to a desired position of the scanning line,
• wherein the second rotating step is performed after the first rotating step is performed.

An image forming apparatus comprising:

• an optical scanner which irradiates a light beam to a scanned surface of an image support to form an electrostatic latent image on the image support surface;
• and
• an image formation unit forming an image on a recording material based on the electrostatic latent image formed on the image support surface,
• the optical scanner comprising:
• a light source emitting a light beam;
• at least one reflection mirror having a reflection surface, a first axis parallel to a main-scanning correspondence direction on the reflection surface, and a second axis along the reflection surface and perpendicular to the first axis;
• an optical element adjusting a position of a scanning line in a sub-scanning correspondence direction, the optical element having a beam-incidence surface, a third axis parallel to the main-scanning correspondence direction on the beam-incidence surface, and a fourth axis perpendicular to the third axis and along a beam-incidence direction;
• a first adjustment unit provided to rotate said at least one reflection mirror around the second axis in order to attain uniformity of a scanning speed of the optical scanner in the sub-scanning correspondence direction;
• and
• a second adjustment unit provided to rotate said optical element around the fourth axis in order to correct an inclination of the scanning line in the sub-scanning correspondence direction to a desired position of the scanning line.

An optical scanner which irradiates a light beam to a scanned surface of an image support to form an electrostatic latent image on the image support surface, the optical scanner comprising:

• a light source emitting a light beam;
• at least one reflection mirror having a reflection surface, a first axis parallel to a main-scanning correspondence direction on the reflection surface, and a second axis along the reflection surface and perpendicular to the first axis;
• an optical element adjusting a position of a scanning line in a sub-scanning correspondence direction, the optical element having a beam-incidence surface, a third axis parallel to the main-scanning correspondence direction on the beam-incidence surface, and a fourth axis perpendicular to the third axis and along a beam-incidence direction;
• first adjustment means for rotating said at least one reflection mirror around the second axis in order to attain uniformity of a scanning speed of the optical scanner in the sub-scanning correspondence direction;
• and
• second adjustment means for rotating said optical element around the fourth axis in order to correct an inclination of the scanning line in the sub-scanning correspondence direction to a desired position of the scanning line.

An optical scanner which irradiates a light beam to a scanned surface of an image support to form an electrostatic latent image on the image support surface, the optical scanner comprising:

• a light source emitting a light beam;
• at least one reflection mirror having a reflection surface;
• an optical element adjusting a position of a scanning line in a sub-scanning correspondence direction, the optical element having a beam-incidence surface, a first axis parallel to the main-scanning correspondence direction on the beam-incidence surface, and a second axis perpendicular to the first axis and along a beam-incidence direction;
• first supporting means for supporting a portion of said at least one reflection mirror;
• first adjustment means for rotating said at least one reflection mirror about the first supporting unit in a direction perpendicular to the reflection surface and changing a distance between the reflection surface and the image support surface in order to attain uniformity of a scanning speed of the optical scanner in the sub-scanning correspondence direction;
• second supporting means for supporting a portion of said optical element;
• and
• second adjustment means for rotating said optical element about the second supporting unit in a direction of the second axis in order to correct an inclination of the scanning line in the sub-scanning correspondence direction to a desired position of the scanning line.

An image forming apparatus comprising:

• an optical scanner which irradiates a light beam to a scanned surface of an image support to form an electrostatic latent image on the image support surface;
• and
• an image formation unit forming an image on a recording material based on the electrostatic latent image formed on the image support surface,
• the optical scanner comprising:
• a light source emitting a light beam;
• at least one reflection mirror having a reflection surface, a first axis parallel to a main-scanning correspondence direction on the reflection surface, and a second axis along the reflection surface and perpendicular to the first axis;
• an optical element adjusting a position of a scanning line in a sub-scanning correspondence direction, the optical element having a beam-incidence surface, a third axis parallel to the main-scanning correspondence direction on the beam-incidence surface, and a fourth axis perpendicular to the third axis and along a beam-incidence direction;
• first adjustment means for rotating said at least one reflection mirror around the second axis in order to attain uniformity of a scanning speed of the optical scanner in the sub-scanning correspondence direction;
• and
• second adjustment means for rotating said optical element around the fourth axis in order to correct an inclination of the scanning line in the sub-scanning correspondence direction to a desired position of the scanning line.