A light scanning apparatus, including: a light source configured to emit a light beam; and a rotary polygon mirror configured to deflect the light beam emitted from the light source so that the light beam scans a surface of a photosensitive member, wherein the rotary polygon mirror is formed in a four-sided polygon, and wherein a difference between a pair of diametrically opposed interior angles of the rotary polygon mirror is larger than 0.03°, and a difference between another pair of diametrically opposed interior angles of the rotary polygon mirror is 0.03° or less.

An image forming apparatus includes a rotating polygon mirror, a motor, a bearing portion, a measurement processing portion, and a determination processing portion. The rotating polygon mirror causes a light beam emitted from the light source to be scanned. The motor rotates the rotating polygon mirror. The bearing portion rotatably supports a rotation shaft of the motor via a lubricant. The measurement processing portion measures a transition time that is a time required for the motor to transition from a stationary state to a driving state in which the motor rotates at a predetermined speed. The determination processing portion determines whether or not a maintenance is required, based on the transition time measured by the measurement processing portion.

An undercoat layer of an electrophotographic photosensitive member includes a binder resin, and a complex particle composed of a core particle coated with tin oxide doped with zinc.

A curl correcting device includes a pair of fixed guides and a change-over guide. The pair of fixed guides composes a curved part of a conveyance path. The change-over guide is provided to be contactable with a sheet from a radial outer side of the curved part. An outer guide includes a pair of side pressing parts and a bulge part. The pair of side pressing parts is formed at both ends in a width direction. The bulge part is formed between the pair of side pressing parts so as to bulge toward the radial outer side of the curved part. The change-over guide is configured to move to a first correcting position when the sheet curled along the conveyance direction is conveyed through the conveyance path and to move to a second correcting position when the sheet curled along the width direction is conveyed through the conveyance path.

An image forming apparatus for forming an image on a recording material by a plurality of color materials, the apparatus includes: a determination unit configured to determine, based on converted data that are converted from image data corresponding to each image formed by the plurality of color materials, values each relating to an area of a respective color material caused to adhere to a recording material; and a detection unit configured to detect, based on the values each relating to the area of the respective color material that the determination unit determines, an overlapping of color materials.

The image forming apparatus includes a sheet storing unit insertably and pullably attached to the frame unit, an image forming unit, and a frame unit. The frame unit includes two frame members parallel to each other with a predetermined distance therebetween and are connected and fixed to each other. The two frame members respectively include engaged portions. The sheet storing unit includes engaging portions respectively engageable with the engaged portions in a state where the sheet storing unit is inserted in the frame unit. In a state where the engaging portions respectively engage with the engaged portions, the engaging portions that respectively engage with the engaged portions and a portion between the two engaging portions of the sheet storing unit serve as strengthening members to regulate deformation of the two frame members by at least a predetermined amount.

An information processing apparatus includes a processor configured to shift to an energy saving mode in which predetermined functions are inactivated. The processor includes a detection unit that detects a shutdown operation in the energy saving mode of the information processing apparatus, an operation reception unit that displays, when the shutdown operation is detected, a screen in which a user is prompted to determine whether performance of a shutdown process is to be continued, the operation reception unit receiving an operation through the screen, and a shutdown unit that performs the shutdown process when an operation to continue performance of the shutdown process is received through the screen.

A sheet processing apparatus that can suppress a reduction in a quality of a finish of a fold part of a stack of center-folded sheets without losing an ease of center-folding. The sheet processing apparatus comprises a creasing unit for forming a folding stripe on a sheet so as to facilitate folding the sheet, and an acquisition unit for acquiring information related to a thickness of the sheet. One or more sheets to be provided with folding stripes are determined, from among a plurality of sheets to be folded, according to the information related to the thickness of the sheets, and each of the determined one or more sheets are provided with a folding stripe.

An embodiment includes a method of determining whether or not to perform a decoloring process on a sheet. A front position of a sheet fed in a sheet transport direction is detected. A presence or absence of an identification mark on a front portion of the sheet outside of an image forming area of the sheet is detected, after detecting the front position of the sheet. A determination is made of whether an image formed with decolorable color material is printed on the sheet based on whether an identification mark is detected on the front portion of the sheet. When the image formed with decolorable color material is determined to be printed on the sheet, the image is decolored.

A paper feeding device includes a first tray, a first elevation motor for moving up the first tray, a second tray for placing paper sheets, a second elevation motor for moving up the second tray, a separation plate disposed between the first tray and the second tray, an upper sensor unit and a lower sensor unit attached to the first tray, a light blocking plate attached to the second tray, and a controller. The paper feeding device has a tray parallel elevation mode in which both the trays are moved up in parallel in a state where the separation plate is removed.