Deflecting mirror adjusting device for an image forming apparatus

A device for adjusting a position of a deflecting mirror included in an exposing system of an image forming apparatus, said device comprising:

• a support member supporting said deflecting mirror;
• an adjusting member contacting said deflecting mirror for varying an inclination of said deflecting mirror in a main scanning direction, said adjusting member comprising an eccentric cam;
• and
• a drive source for driving said adjusting member;
• wherein a surface of said eccentric cam contacting said deflecting mirror is tapered.

A device for adjusting a position of a deflecting mirror included in an exposing system of an image forming apparatus, said device comprising:

• a support member supporting said deflecting mirror;
• an adjusting member contacting said deflecting mirror for varying an inclination of said deflecting mirror in a main scanning direction, said adjusting member comprising an eccentric cam;
• plural drive sources at opposite ends of the deflecting mirror, respectively, for driving said adjusting member;
• image forming means for forming patterns for measurement of a positional deviation between different colors on both edge portions in the main scanning direction;
• a plurality of pattern sensing means respectively assigned to said patterns different in color, for determining a positional deviation at least in a subscanning direction color by color;
• and
• control means for controlling said drive sources such that the deflecting mirror is adjusted on the basis of an equation:
• .DELTA..theta.=sin.sup.-1 (sin .theta.+.DELTA.y/e)-.theta.,e.noteq.0
• where .DELTA..theta. denotes an angle of movement of said eccentric cam to occur in a preselected time interval, .DELTA.y denotes a displacement of said deflecting mirror to occur in the preselected time interval .DELTA.t, e denotes an eccentricity of said eccentric cam, and .DELTA.t denotes a unit time interval in which the displacement .DELTA.y is to end, such that an approximation is determined with an output of said plurality of pattern sensing means, and such that the displacement .DELTA.y of said equation is determined on the basis of the approximation.

A device for adjusting a position of a deflecting mirror included in an exposing system of an image forming apparatus, said device comprising:

• a support member supporting said deflecting mirror;
• an adjusting member contacting said deflecting mirror for varying an inclination of said deflecting mirror in a main scanning direction, said adjusting member comprising an eccentric cam;
• plural drive sources at opposite ends of the deflecting mirror, respectively, for driving said adjusting member;
• image forming means for forming patterns for measurement of a positional deviation between different colors on both end portions in the main scanning direction;
• a plurality of pattern sensing means respectively assigned to said patterns different in color, for determining a positional deviation at least in a subscanning direction color by color;
• and
• control means for controlling said drive sources such that the deflecting mirror is adjusted on the basis of an equation:
• .DELTA..theta.=sin.sup.-1 (sin .theta.+.DELTA.y/e)-.theta.,e.noteq.0
• where .DELTA..theta. denotes an angle of movement of said eccentric cam to occur in a preselected time interval, .DELTA.y denotes a displacement of said deflecting mirror to occur in the preselected time interval .DELTA.t, e denotes an eccentricity of said eccentric cam, and .DELTA.t denotes a unit time interval in which the displacement .DELTA.y is to end, and such that when information representative of a position of rotation of said eccentric cam is processed as a number of consecutive pulses generated by a clock on the basis of said equation, a number of pulses corresponding to the displacement .DELTA.y is determined every preselected time interval .DELTA.t with a fragment below a decimal point rounded to determine the angle of movement of said eccentric cam.

A device for adjusting a position of a deflecting mirror of an exposing system included in an image forming apparatus in order to correct a deviation of an image on an image carrier included in said image forming apparatus, said device comprising:

• a pair of first supporting means respectively supporting opposite ends of a surface of said deflecting mirror in a main scanning direction, and for moving said deflecting mirror;
• second supporting means resiliently contacting a rear of said deflecting mirror at one end of said deflecting mirror, and retaining said deflecting mirror in cooperation with one of said pair of first supporting means;
• and
• third supporting means resiliently contacting a rear of said deflecting mirror at the other end of said deflecting mirror, and retaining said deflecting mirror in cooperation with the other of said pair of first supporting means;
• said second and third supporting means each comprising a presser member supported by a stationary member and rotatable about a fulcrum defined by a shaft which extends parallel to a subscanning direction as viewed on said deflecting mirror.

A device for adjusting a deflecting mirror of a color image forming apparatus including writing means for deflecting a light beam with said deflecting mirror to thereby form a latent image on an image carrier with a deflected light beam, and a first drive source for moving said image carrier, and causing said writing means to write a plurality of images of different colors on said image carrier for forming a plurality of latent images, developing said plurality of latent images to thereby form a plurality of images of different colors, and superposing said plurality of images to thereby form a color image, said device comprising:

• pattern forming means for forming a plurality of patterns for measuring a positional deviation between the images of a same color or of different colors, said writing means including said pattern forming means;
• first sensing means corresponding to said plurality of patterns, for detecting a positional deviation at least in a subscanning direction;
• first storing means for storing results of detection output from said first sensing means;
• second sensing means for detecting an irregularity in the movement of said image carrier;
• second storing means for storing results of detection output from said second sensing means;
• support members supporting said deflecting mirror;
• two eccentric cams for varying an inclination of said deflecting mirror in a main scanning direction in contact with opposite ends of said deflecting mirror;
• a second drive source for driving said eccentric cams, wherein after said pattern forming means has formed said plurality of patterns, and said first sensing means has detected a positional deviation, said second drive source is controlled, as a correction process, at one or both sides of said deflecting mirror on the basis of an output of at least one of said first and second sensing means;
• and
• control means for executing, if a positional deviation represented by an output of said first sensing means and resulting from a first correction process does not lie in an allowable range, and when said eccentric cams are driven to displace said deflecting mirror, a second correction process, and for repeating, if a positional deviation represented by the output of said first sensing means and resulting from said second correction process does not lie in the allowable range, said correction process a preselected number of times.