Scanning optical device and image forming apparatus with bearing surfaces and regulating portions constructed to reduce laser deviation of a reflection mirror

A scanning optical device for scanning an object to be scanned with a laser light, said scanning optical device comprising:

• a light source constituted to emit the laser light;
• a deflection unit constituted to deflect the laser light emitted from said light source;
• a reflecting mirror constituted to reflect the laser light deflected by said deflection unit to guide to the object to be scanned;
• a housing constituted to accommodate said deflection unit and said reflecting mirror;
• a cover constituted to cover an opening of said housing;
• and
• an elastic member constituted to urge said reflecting mirror toward said housing,
• wherein said reflecting mirror includes a first surface urged by said elastic member, a second surface opposite to said first surface, a third surface substantially perpendicular to said first surface and said second surface, in parallel with a longitudinal direction of said reflecting mirror and closer to said opening of said housing, and fourth surface opposite to said third surface,
• wherein said housing includes a bearing surface constituted to support said second surface, and said cover includes a regulating portion constituted to regulate movement of said reflecting mirror to a mirror widthwise direction, substantially perpendicular to the longitudinal direction and substantially parallel with said second surface, and toward the opening of said housing, said regulating portion being provided opposite to only a part of said third surface so that a ridge line of said reflecting mirror between said second surface and said third surface does not contact said regulating member even an attitude of said reflecting mirror changes in a direction away from said bearing surface when said reflecting mirror is viewed in the longitudinal direction,
• wherein two sets of a combination of said elastic member, said bearing surface and said regulating portion are provided in the longitudinal direction, and
• wherein a number of said bearing surface of one set of the combination is two and a number of said bearing surface of the other set of the combination is one.

A scanning optical device for scanning an object to be scanned with a laser light, said scanning optical device comprising:

• a light source constituted to emit the laser light;
• a deflection unit constituted to deflect the laser light emitted from said light source;
• a reflecting mirror constituted to reflect the laser light deflected by said deflection unit to guide to the object to be scanned;
• a housing constituted to accommodate said deflection unit and said reflecting mirror;
• and
• an elastic member constituted to urge said reflecting mirror toward said housing,
• wherein said reflecting mirror includes a first surface urged by said elastic member, a second surface opposite to said first surface, a third surface substantially perpendicular to said first surface and said second surface, in parallel with a longitudinal direction of said reflecting mirror and closer to an opening of said housing, and fourth surface opposite to said third surface,
• wherein said housing includes a bearing surface constituted to support said second surface, and a regulating portion constituted to regulate movement of said reflecting mirror to a mirror widthwise direction, substantially perpendicular to the longitudinal direction and substantially parallel with said second surface, and toward said opening of said housing, said regulating portion being provided opposite to only a part of said third surface so that a ridge line of said reflecting mirror between said second surface and said third surface does not contact said regulating member even an attitude of said reflecting mirror changes in a direction away from said bearing surface when said reflecting mirror is viewed in the longitudinal direction,
• wherein when said reflecting mirror is supported on said bearing surface at a correct attitude, a portion of said housing opposite to the ridge line of said reflecting mirror between said second surface and said third surface becomes a shape more recessed than said regulating portion with respect to the direction toward said opening of said housing,
• wherein when said regulating portion is a first regulating portion, said housing includes a second regulating portion configured to regulate movement of said reflecting mirror to a direction opposite to the direction toward said opening of said housing, said second regulating portion being provided opposite to only a part of said fourth surface so that a ridge line of said reflecting mirror between said second surface and said fourth surface does not contact said second regulating portion even the attitude of said reflecting mirror changes in a direction away from said bearing surface when said reflecting mirror is viewed in the longitudinal direction, and
• wherein a distance between said first regulating portion and said second regulating portion is larger than a width of said reflecting mirror.