Abstract: A zoom lens, including, in order from object side, a positive first unit, a negative second unit, a positive third unit, a negative fourth unit, and a positive fifth unit. The first unit includes, in order from object side, a negative first sub unit which does not move for focusing, a positive second sub unit which moves during focusing, and a positive third sub unit which does not move for focusing and includes a negative lens. 1.6<L2tm/L2t<1000.0; L2w/L3w<1.0; and ?0.5<f2/f3<?0.05 are satisfied, where L2t represents an second-third unit interval at a telephoto end, L2tm represents second-third unit interval at a zoom position at which an interval between the third and fourth units is minimum, L2w represents second-third unit interval at a wide-angle end, L3w represents third-fourth unit interval at the wide-angle end, and f2 and f3 represent focal lengths of the second and third units, respectively.

Abstract: A zoom lens, including, in order from object side to image side: a positive first lens unit which does not move during zooming; a negative second lens unit for zooming; a positive third lens unit for zooming; a negative fourth lens unit which moves during zooming; and a positive fifth lens unit which does not move during zooming, in which: 0.6<|?3F|<1.0, ?4.0<f4/f3<?1.0, and 20<L2w/L3w<300 are satisfied, where ?3F is a lateral magnification of the third lens unit at a position at which a lateral magnification of the second lens unit becomes ?1; f3 and f4 are respectively focal lengths of the third and fourth lens units; L2w is a gap between the second and third lens units at a wide angle end; and L3w is a gap between the third and fourth lens units at the wide angle end.

Abstract: An image forming apparatus to which a sheet positioning device can be provided to perform a sheet positioning includes an image forming device and a sheet positioning device that includes a sheet setting plate, a pair of side fence units disposed facing each other along opposite sides of the sheet setting plate to move in a lateral direction of the sheet, a moving mechanism to move the pair of side fence units, a contact member to contact and press the sheet, a position detector to detect the position of the contact member, and a controller moving the pair of side fence units when the sheet is placed on the sheet setting plate, halting movement of the pair of side fence units after the contact member has contacted and pressed the sheet, and moving the pair of side fence units again based on detection results obtained by the position detector.

Abstract: A lens apparatus includes, in order from an object side: a first lens unit; an aperture stop; and a positive second lens unit. The first lens unit includes, in order from the object side, a first negative lens, a second negative lens having at least one aspheric surface, and a positive lens. The second lens unit includes at least one negative lens and at least two positive lenses. The first and second negative lenses of the first lens unit are meniscus lenses having a surface convex toward the object side. The focal length of the optical system, the focal lengths of the first and second lens units, the mean values of Abbe constants of the positive lens and the negative lenses of the first lens unit, and the mean values of Abbe constants of the positive lenses and the negative lenses of the second lens unit are appropriately configured.

Abstract: An image forming apparatus, in which a method of handling a sheet conveyance error is performed, includes an apparatus body, a fixing unit fixing an image to a recording medium at a nip area thereof, a sheet conveying path, a sheet output roller unit outputting the recording medium outside the apparatus body, a sheet output detector detecting the recording medium, a post-fixing nip detector detecting the recording medium, a notifying unit notifying a user of an error recovery process when the error is detected by the error detector, and a controller. A distance from the post-fixing nip detector to the sheet output detector is smaller than a given size of the recording medium. When the error is detected by the error detector and the recording medium is detected by the sheet output detector, the controller causes the notifying unit to display a different process according to the detection results.

Abstract: A zoom lens, including, in order from object side to image side: a positive first lens unit which does not move during zooming; a negative second lens unit for zooming; a positive third lens unit for zooming; a negative fourth lens unit which moves during zooming; and a positive fifth lens unit which does not move during zooming, in which: 0.6<|?3F|<1.0, ?4.0<f4/f3<?1.0, and 20<L2w/L3w<300 are satisfied, where ?3F is a lateral magnification of the third lens unit at a position at which a lateral magnification of the second lens unit becomes ?1; f3 and f4 are respectively focal lengths of the third and fourth lens units; L2w is a gap between the second and third lens units at a wide angle end; and L3w is a gap between the third and fourth lens units at the wide angle end.

Abstract: An image forming apparatus to which a sheet positioning device can be provided to perform a sheet positioning includes an image forming device and a sheet positioning device that includes a sheet setting plate, a pair of side fence units disposed facing each other along opposite sides of the sheet setting plate to move in a lateral direction of the sheet, a moving mechanism to move the pair of side fence units, a contact member to contact and press the sheet, a position detector to detect the position of the contact member, and a controller moving the pair of side fence units when the sheet is placed on the sheet setting plate, halting movement of the pair of side fence units after the contact member has contacted and pressed the sheet, and moving the pair of side fence units again based on detection results obtained by the position detector.

Abstract: A sheet positioning device includes a sheet setting plate, first and second regulating members disposed facing each other to move in an orthogonal direction to a sheet conveyance direction to regulate positions of two facing ends of the sheet on the plate by contacting these ends, a driving mechanism to move the first regulating member in the orthogonal direction, first and second contact detectors mounted on the first and second regulating members to detect contact of the two facing ends, and a controller to stop the driving mechanism based on detection results obtained by the first and second contact detectors. The first and second regulating members are used to adjust a position of the sheet to a predetermined position. Respective contact surfaces of the first and second contact detectors with the sheet extend over an entire maximum loadable range In a sheet setting direction on the plate.

Abstract: A sheet feeding device that is incorporatable in an image forming apparatus includes an endless belt disposed facing an upper surface of a sheet stack to convey sheets of the sheet stack forward in a first moving direction of a surface thereof, an attraction unit to attract an uppermost sheet of the sheet stack to the endless belt, a contact and separation unit to contact and separate the endless belt relative to the sheet stack, and a controller to cause the endless belt to contact or substantially contact the upper surface of the sheet stack to attract the uppermost sheet to the endless belt, perform a pre-separation operation in which the endless belt moves in a reverse direction that is opposite the sheet conveyance direction, and then perform a separating operation in which the endless belt separates from the sheet stack.

Abstract: A sheet feeding device that is incorporatable in an image forming apparatus includes an endless belt disposed facing an upper surface of a sheet stack to convey sheets of the sheet stack forward in a first moving direction of a surface thereof, an attraction unit to attract an uppermost sheet of the sheet stack to the endless belt, a contact and separation unit to contact and separate the endless belt relative to the sheet stack, and a controller to cause the endless belt to contact or substantially contact the upper surface of the sheet stack to attract the uppermost sheet to the endless belt, perform a pre-separation operation in which the endless belt moves in a reverse direction that is opposite the sheet conveyance direction, and then perform a separating operation in which the endless belt separates from the sheet stack.

Abstract: A tube-shaped film, made of fluorine resin, has a fold-free, smooth, and uniform inner peripheral surface formed thereon by a surface treatment. An apparatus for treating the inner peripheral surface of the tube-shaped film includes a holding device for holding the tube-shaped film on the inner peripheral surface of a cylindrical body with a cylindrical configuration of the tube-shaped film maintained. A treatment device is inserted into the cylindrical body to treat the inner peripheral surface of the tube-shaped film held on the inner peripheral surface of the cylindrical body. The holding device and the treatment device make a uniform linear motion relative to each other and a uniform rotary motion relative to each other.

Abstract: A process for modifying surfaces of fluorine resins including irradiating an ultraviolet laser beam on the surfaces in the presence of an inorganic silicon compound. The inorganic silicon compound could be a silicate, silicon oxide, silicon nitride, or silicon carbide.

Abstract: An apparatus for measuring the thickness of a thin film utilizing an interferometric method includes a light source for generating a monochromatic light beam, a scanner for scanning the light beam on a thin film in such a manner that an incident angle thereto is continuously varied from .alpha. to (-.alpha.), a first detector for detecting the incident angle of the light beam and a second detector for detecting an interference pattern caused by light beams reflected from the top and bottom surfaces of the thin film. The thickness of the thin film is obtained in accordance with a geometrical optical relationship defined between adjacent fringes contained in the detected interference pattern.