Abstract: The zoom lens includes, in order from object side to image side, a positive first lens unit (LU), a negative second LU, a positive third LU, and a rear lens group including at least one LU. The zoom lens further includes an aperture stop. A LU arranged on image side of aperture stop moves during zooming. The first LU consists of at least two positive lenses (TPL), and two negative lenses (TNL). An average partial dispersion ratio (APDR) of TNL, APDR of TPL having highest refractive powers of at least TPL, an average Abbe number (AAN) of TNL, AAN of TPL, larger one of Abbe numbers of TNL, smaller one of Abbe numbers of TPL, focal lengths of first and second LUs, a distance from an optical surface closest to object side to image plane, and a focal length of zoom lens at a telephoto end are each appropriately set.

Abstract: A sheet ejection device includes a sheet stacker, a retainer, and a biasing member. The sheet stacker has a stacker face and a coupling portion. The sheet stacker is configured to stack a sheet on the stacker face. The retainer has a coupling portion and an adjuster configured to rotate the sheet stacker to adjust an angle of the stacker face. The retainer is configured to retain the sheet stacker to be movable in a vertical direction. The biasing member is coupled to the sheet stacker and the retainer to apply a biasing force to bias the sheet stacker in an upward direction to the retainer. The sheet stacker is configured to move in a downward direction against the biasing force, as a number of sheets stacked on the stacker face increases. The coupling portion of the retainer is configured to move when the adjuster rotates the sheet stacker.

Abstract: At least one embodiment of an optical system includes, in order from an object side to an image side, a front unit having a plurality of lenses, an aperture stop, and a rear unit having a positive refractive power. In at least one embodiment, a positive lens and three or more negative lenses are disposed in the front unit, and the material of negative lenses included in the front unit, the focal length of the front unit, and the focal length of the entire optical system are set appropriately.

Abstract: At least one embodiment of an optical system includes, in order from an object side to an image side, a front unit including a plurality of lenses, an aperture stop, and a rear unit having a positive refractive power. In at least one embodiment, four negative lenses are consecutively arranged from a side of the front unit closest to the object side, and a focal length of the front unit and a focal length of the rear unit are appropriately set.

Abstract: A sheet feeding device includes a device body including a stopper portion and a feeding tray detachably mounted to the device body. The feeding tray includes a stopper, a lock assembly, and an operating member. The stopper includes a stopped portion movable between a stop position at which the stopped portion is stopped by the stopper portion and a release position. The lock assembly prevents drawing of the feeding tray from the device body. An operating member rotates from an initial state by a predetermined angle to move the stopped portion from the stop position to the release position. The lock assembly restricts rotation of the operating member when the lock assembly is locked. The stopped portion is movable from the stop position to the release position with an operation of mounting the feeding tray to a mount position of the device body without rotation of the operating member.

Abstract: A sheet feeder, which is included in an image forming apparatus, includes a pair of first regulators and a pair of second regulators. The pair of first regulators is disposed movable in a width direction of a recording medium loaded on the sheet loader and is configured to contact a side end of the recording medium and regulate a position of the recording medium in the width direction. The pair of second regulators is configured to be detachably attachable to multiple attachment positions of the sheet tray selectably.

Abstract: A sheet feeding device includes a device body including a stopper portion and a feeding tray detachably mounted to the device body. The feeding tray includes a stopper, a lock assembly, and an operating member. The stopper includes a stopped portion movable between a stop position at which the stopped portion is stopped by the stopper portion and a release position. The lock assembly prevents drawing of the feeding tray from the device body. An operating member rotates from an initial state by a predetermined angle to move the stopped portion from the stop position to the release position. The lock assembly restricts rotation of the operating member when the lock assembly is locked. The stopped portion is movable from the stop position to the release position with an operation of mounting the feeding tray to a mount position of the device body without rotation of the operating member.

Abstract: Provided is a zoom lens, including, in order from an object side to an image side: a positive first lens unit; a negative second lens unit; a positive third lens unit; and a rear lens group including at least one lens unit, in which the first lens unit is not configured to move for zooming, and the second lens unit, the third lens unit, and at least one lens unit included in the rear lens group are configured to move during zooming so that intervals between adjacent lens units are changed during zooming. A lateral magnification of the second lens unit at a wide angle end, a lateral magnification of the second lens unit at a telephoto end, a movement amount of the third lens unit during zooming from the wide angle end to the telephoto end, and a total length of the zoom lens are appropriately set.

Abstract: An objective optical system for endoscope includes, a first group having a positive refractive power, an aperture stop, and a second group having a positive refractive power, wherein the first group includes a first lens having a negative refractive power, and a second lens having a positive refractive power, the second group includes a cemented lens, and the cemented lens includes a third lens having a positive refractive power and a fourth lens having a negative refractive power, and the following conditional expressions (1), (2), (3), (4), (7) and (9) are satisfied: 0.13?La/Lb?0.17??(1), ?2.7?f4/f??2.2??(2), ?0.7?(ne2×f2)/(ne4×f4)?0??(3), 2.5??d3/?d4?3.5??(4) ?2.6?r2o/rcc??2??(7), and ?1.2?r2i/f2??0.9??(9).

Abstract: A sheet feeder, which is included in an image forming apparatus, includes a pair of first regulators and a pair of second regulators. The pair of first regulators is disposed movable in a width direction of a recording medium loaded on the sheet loader and is configured to contact a side end of the recording medium and regulate a position of the recording medium in the width direction. The pair of second regulators is configured to be detachably attachable to multiple attachment positions of the sheet tray selectably.

Abstract: An objective optical system for endoscope includes, a first group having a positive refractive power, an aperture stop, and a second group having a positive refractive power, wherein the first group includes a first lens having a negative refractive power, and a second lens having a positive refractive power, the second group includes a cemented lens, and the cemented lens includes a third lens having a positive refractive power and a fourth lens having a negative refractive power, and the following conditional expressions (1), (2), (3), (4), (7) and (9) are satisfied: 0.13?La/Lb?0.17 ??(1), ?2.7?f4/f??2.2 ??(2), ?0.7?(ne2×f2)/(ne4×f4)?0 ??(3), 2.5??d3/?d4?3.5 ??(4) ?2.6?r2o/rcc??2 ??(7), and ?1.2?r2i/f2??0.9 ??(9).

Abstract: A sheet container, which is included in an image forming apparatus, includes a container body, a body side stopper device, a sheet tray, a tray side stopper device, a tray handler, a releasing device, and a tray locking device. The tray side stopper device has a tray side stopper portion to be engaged with the body side stopper device. The releasing device moves the body side stopper device along with movement of the tray handler from the first position to the second position. The releasing device cancels retention of the sheet tray in the container body and the tray locking device prevents the tray handler from canceling the retention of the sheet tray in the container body. The tray locking device regulates movement of the tray handler from the first position to the second position and moves the tray side stopper portion without moving the tray handler.

Abstract: At least one embodiment of an optical system includes, in order from an object side to an image side, a front unit having a plurality of lenses, an aperture stop, and a rear unit having a positive refractive power. In at least one embodiment, a positive lens and three or more negative lenses are disposed in the front unit, and the material of negative lenses included in the front unit, the focal length of the front unit, and the focal length of the entire optical system are set appropriately.

Abstract: At least one embodiment of an optical system includes, in order from an object side to an image side, a front unit including a plurality of lenses, an aperture stop, and a rear unit having a positive refractive power. In at least one embodiment, four negative lenses are consecutively arranged from a side of the front unit closest to the object side, and a focal length of the front unit and a focal length of the rear unit are appropriately set.

Abstract: A sheet container, which is included in an image forming apparatus, includes a container body, a body side stopper device, a sheet tray, a tray side stopper device, a tray handler, a releasing device, and a tray locking device. The tray side stopper device has a tray side stopper portion to be engaged with the body side stopper device. The releasing device moves the body side stopper device along with movement of the tray handler from the first position to the second position. The releasing device cancels retention of the sheet tray in the container body and the tray locking device prevents the tray handler from canceling the retention of the sheet tray in the container body. The tray locking device regulates movement of the tray handler from the first position to the second position and moves the tray side stopper portion without moving the tray handler.

Abstract: Provided is a zoom lens, including, in order from an object side to an image side: a positive first lens unit; a negative second lens unit; a positive third lens unit; and a rear lens group including at least one lens unit, in which the first lens unit is not configured to move for zooming, and the second lens unit, the third lens unit, and at least one lens unit included in the rear lens group are configured to move during zooming so that intervals between adjacent lens units are changed during zooming. A lateral magnification of the second lens unit at a wide angle end, a lateral magnification of the second lens unit at a telephoto end, a movement amount of the third lens unit during zooming from the wide angle end to the telephoto end, and a total length of the zoom lens are appropriately set.

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: 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: 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 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.