Abstract: Provided is a detecting apparatus including an illumination optical system for emitting an image bearing member with a light beam emitted from a light source unit, an imaging optical system including an imaging optical element for imaging an image on the surface of the image bearing member, a light receiving unit for detecting the image on the image bearing member which has been imaged by the imaging optical system, and a calculation unit for detecting image information on the image on the image bearing member from a detection signal received from the light receiving unit. In the detecting apparatus, at least one optical plane of the imaging optical element is configured to refract an imaging system principal ray after passing therethrough in a direction of farther becoming apart from the light source unit than the imaging system principal ray before passing through the optical plane.

Abstract: Provided are a scanning optical apparatus including an incident optical system for guiding a light beam emitted from a light source unit to a deflecting unit, an imaging optical system for imaging, on the surface to be scanned, a light beam deflectively scanned by the deflecting unit, and an optical path changing unit which is provided on an optical path between the deflecting unit and the surface to be scanned and includes at least two optical path changing elements. One of an optical path changing element having a minimum reflectance has a reflectance equal to or smaller than 70% in all areas used for image formation. An on-axis light beam deflected by the deflecting unit enters the optical path changing element having the minimum reflectance at a minimum angle of the at least two optical path changing elements.

Abstract: A scanning optical apparatus includes scanning units, a deflector. Each of the apparatuses includes a light source, an imaging optical system including imaging optical elements imaging a beam deflected by the deflector on a scanning surface. The scanning surfaces are scanned with beams in opposing directions. When a main scanning direction of the first scanning unit is a Y positive direction, a sign is the same between ?1h(Y1min)×?1r and ?2h(Y1min)×?2r. Here, ?1h(y), ?2h(y) denote orientation angles between the Y axis and a slow axis at a Y direction position y of first/second imaging optical elements from an optical axis, the imaging optical elements each being an imaging optical element having a largest thickness among them of the imaging optical systems, ?1r and ?2r denote angles between the Y axis and polarization directions of the beams reaching the imaging optical elements, and Y1min denotes a Y position where ?1h(y) becomes minimum.

Abstract: A color image forming apparatus obtaining a high quality color image with little write start misregistration among optical scanning devices, includes a plurality of optical scanning devices respectively including an incident optical unit guiding a light beam from a light source unit to a deflection unit, an imaging optical system allowing the light beam deflectively scanned by the deflection unit to be focused on a scanned surface, and an optical system for synchronous detection for adjusting image start timing on the scanned surface by using a part of the light beam deflectively scanned by the deflection unit. A ratio of a focal length of the optical system for synchronous detection to a focal length of the imaging optical system is set appropriately in a main scanning section of the plurality of optical scanning devices for obtaining a black color image and color images other than the black color image.

Abstract: Provided is a detecting apparatus including an illumination optical system for emitting an image bearing member with a light beam emitted from a light source unit, an imaging optical system including an imaging optical element for imaging an image on the surface of the image bearing member, a light receiving unit for detecting the image on the image bearing member which has been imaged by the imaging optical system, and a calculation unit for detecting image information on the image on the image bearing member from a detection signal received from the light receiving unit. In the detecting apparatus, at least one optical plane of the imaging optical element is configured to refract an imaging system principal ray after passing therethrough in a direction of farther becoming apart from the light source unit than the imaging system principal ray before passing through the optical plane.

Abstract: A scanning optical apparatus includes scanning units, a deflector. Each of the apparatuses includes a light source, an imaging optical system including imaging optical elements imaging a beam deflected by the deflector on a scanning surface. The scanning surfaces are scanned with beams in opposing directions. When a main scanning direction of the first scanning unit is a Y positive direction, a sign is the same between ?1h(Y1min)×?1r and ?2h(Y1min)×?2r. Here, ?1h(y), ?2h(y) denote orientation angles between the Y axis and a slow axis at a Y direction position y of first/second imaging optical elements from an optical axis, the imaging optical elements each being an imaging optical element having a largest thickness among them of the imaging optical systems, ?1r and ?2r denote angles between the Y axis and polarization directions of the beams reaching the imaging optical elements, and Y1min denotes a Y position where ?1h(y) becomes minimum.

Abstract: An optical scanning apparatus includes light source units; a deflecting unit, incident optical systems provided so as to correspond to the light source units, and at least one synchronous detection optical system that controls a timing at which the light beams form images on the surfaces to be scanned. The synchronous detection optical system includes a synchronous detection element, at least one optical path changing unit, and at least one synchronous detection optical element. The synchronous detection element is attached to a circuit substrate of the light source unit arranged to oppose the light source unit that emits a light beam used for synchronous detection, with the deflecting unit therebetween. The synchronous detection optical element and the synchronous detection element are arranged to oppose each other with respect to a line perpendicular to lines connecting a deflection axis of the deflecting unit and optical axes of the imaging optical systems.

Abstract: Provided are a scanning optical apparatus including an incident optical system for guiding a light beam emitted from a light source unit to a deflecting unit, an imaging optical system for imaging, on the surface to be scanned, a light beam deflectively scanned by the deflecting unit, and an optical path changing unit which is provided on an optical path between the deflecting unit and the surface to be scanned and includes at least two optical path changing elements. One of an optical path changing element having a minimum reflectance has a reflectance equal to or smaller than 70% in all areas used for image formation. An on-axis light beam deflected by the deflecting unit enters the optical path changing element having the minimum reflectance at a minimum angle of the at least two optical path changing elements.

Abstract: A color image forming apparatus obtaining a high quality color image with little write start misregistration among optical scanning devices, includes a plurality of optical scanning devices respectively including an incident optical unit guiding a light beam from a light source unit to a deflection unit, an imaging optical system allowing the light beam deflectively scanned by the deflection unit to be focused on a scanned surface, and an optical system for synchronous detection for adjusting image start timing on the scanned surface by using a part of the light beam deflectively scanned by the deflection unit. A ratio of a focal length of the optical system for synchronous detection to a focal length of the imaging optical system is set appropriately in a main scanning section of the plurality of optical scanning devices for obtaining a black color image and color images other than the black color image.

Abstract: Provided is a scanning optical apparatus capable of forming a high quality image while manufacture of an imaging optical system is facilitated, a length of the apparatus in a direction of height is reduced, and unevenness of illuminance distribution (light amount distribution) on a scanned surface is reduced. The scanning optical apparatus includes a single deflecting unit which deflects respective light beams from multiple light source units toward multiple scanned surfaces by different deflection surfaces, multiple incident optical systems each disposed in each light source unit, multiple optical systems which image the respective light beams on the multiple scanned surfaces, and multiple optical path changing units disposed in the respective optical paths between the single deflecting unit and the multiple scanned surfaces. A thin-film characteristic of each of the optical path changing units is different between the respective optical paths.

Abstract: An optical scanning apparatus includes light source units; a deflecting unit, incident optical systems provided so as to correspond to the light source units, and at least one synchronous detection optical system that controls a timing at which the light beams form images on the surfaces to be scanned. The synchronous detection optical system includes a synchronous detection element, at least one optical path changing unit, and at least one synchronous detection optical element. The synchronous detection element is attached to a circuit substrate of the light source unit arranged to oppose the light source unit that emits a light beam used for synchronous detection, with the deflecting unit therebetween. The synchronous detection optical element and the synchronous detection element are arranged to oppose each other with respect to a line perpendicular to lines connecting a deflection axis of the deflecting unit and optical axes of the imaging optical systems.