An image forming apparatus configured to operate in first and second modes of which color gamut is different from each other, the image forming apparatus includes: an exposure unit configured to expose a photosensitive drum; a developing roller configured to form a toner image; a detection unit configured to detect density of the toner image transferred to an intermediate transfer member; and a controller configured to adjust the density based on a value of input image data. A dithering process for controller's controlling of the exposure unit is different depending on whether the operation is in the first mode or the second mode, and in at least a part of the input image data, the density of the toner image formed by the dithering process in the first mode is higher than the density of the toner image formed by the dithering process in the second mode.

An imaging device prints in color and monochromatically, such as black-only. It has a plurality of photoconductive drums, one each for black toner and at least one colored toner. The drums contact and rotate with an intermediate transfer member (ITM) to transfer images at a first transfer. During black-only imaging, the photoconductive drum for the black toner rotates with the ITM at process speed while the drum for the at least one colored toner rotates at less than process speed, often substantially less. The technique reduces consumption of colored toner during black-only imaging and minimizes charge build-up on the drum for the colored toner.

An image forming apparatus includes a housing, a drawer, a photosensitive member rotatably supported by the drawer, a first roller rotatably supported by the drawer, a second roller, an urging member disposed at the housing for urging the second roller toward the first roller, and a positioner. The drawer is movable between a housed position at which the drawer is housed in the housing, and a shifted position at which the drawer is shifted from the housed position toward an exterior of the housing. The second roller is rotatably supported by the housing, disposed to face the first roller, and movable relative to the first roller. The second roller and the first roller pinch a sheet therebetween and transport the sheet toward the photosensitive member. The positioner is disposed at the drawer and positions the second roller relative to the first roller when the drawer is at the housed position.

An image forming device which forms an image for color correction in the margin of a continuous recording medium such as continuous paper as appropriate without causing erroneous detection by a mark sensor at a post-processing stage. In the image forming device, a printing data generator (control section) performs: acquiring a detection criterion to detect a post-processing image for use at the post-processing stage; creating a color correction image to be used for color correction of an original image according to the detection criterion; and arranging the color correction image as an outer area image in an area other than an original image formation area in printing data.

A clutch device includes a drive transmitting shaft; a driving-side engaging member; and a driven-side engaging member. A driving force is transmitted from the driving-side engaging member to the driven-side engaging member. The driving-side engaging member has a driving-side clutch tooth, and the driven-side engaging member has a driven-side clutch tooth capable of being engaged with and released from the driving-side clutch tooth. The driving-side clutch tooth and the driven-side clutch tooth have drive transmitting surfaces inclined so as to axially attracting each other in engagement with each other. At least one of the driving-side clutch tooth and the driven-side clutch tooth has a functional surface on a free end side relative to the drive transmitting surface with respect to the engaging direction. The functional surface is inclined so as to axially separating from a surface of the other clutch tooth in engagement therewith.

A delivery system for delivering a plurality of layers of a powder to a three dimensional (3D) printing system for printing at least one 3D object, the delivery system comprising: a rotatable drum having a rounded photosensitive outer surface, a hopper unit comprising a container for storing the powder, wherein the hopper unit is configured to dispense the powder on the photosensitive outer surface of the rotatable drum. The delivery system further comprises a delivery unit comprising a movable delivery plate having a conductive outer surface, an engine for moving the delivery plate to a working chamber of the 3D printing system, one or more charging electrodes configured to charge the rotatable drum, a charging unit configured to charge the delivery plate. The movable delivery unit is further configured to: electrically and successively attract the dispensed plurality of layers from the rotatable drum outer surface to its conductive outer surface; and transfer the attracted plurality of layers to the working chamber by electrically rejecting the attracted plurality of layers into the working chamber.

An electrophotographic photosensitive member (1) includes a conductive substrate (2) and a photosensitive layer (3). The photosensitive layer (3) is a single-layer photosensitive layer (3c) containing a charge generating material and an electron transport material. The electron transport material includes a compound represented by general formula (1) shown below. An amount of charge of calcium carbonate as measured by charging the calcium carbonate through friction with the photosensitive layer (3) is at least +7.0 C/g. In general formula (1), R.sup.1 and R.sup.2 each represent, independently of each other, a halogen atom, for example. Further, m, n, and Y are as described in the description. ##STR00001##

According to one embodiment, an image forming apparatus includes a plurality of process units, a transferring member, a sensor, and a processor. The plurality of process units include a photosensitive drum, an electric charger which charges the photosensitive drum, an exposing device which includes a plurality of light emitting element rows in a sub-scanning direction configured by the plurality of light emitting elements, and irradiates the photosensitive drum to form a latent image, and a developing device which attaches toner to the latent image to form a toner image. The transferring member receives the toner image from the photosensitive drum. The sensor detects the toner image transferred to the transferring member. The processor calculates a skew deviation amount based on the detection result of the sensor, and controls turning on and off the light emitting element based on a central tendency and the skew deviation amount.

According to one embodiment, an image forming apparatus includes a plurality of process units, a transferring member, a sensor, and a processor. The plurality of process units include a photosensitive drum, an electric charger which charges the photosensitive drum, an exposing device which includes a plurality of light emitting element rows in a sub-scanning direction configured by the plurality of light emitting elements, and irradiates the photosensitive drum to form a latent image, and a developing device which attaches toner to the latent image to form a toner image. The transferring member receives the toner image from the photosensitive drum. The sensor detects the toner image transferred to the transferring member. The processor calculates a skew deviation amount based on the detection result of the sensor, and controls turning on and off the light emitting element based on a central tendency and the skew deviation amount.

An image forming apparatus includes a plurality of photosensitive members; a scanner unit including light sources, a rotatable polygonal mirror, and reflecting members; and a fixing portion. Parts of the laser beams emitted from the light sources are reflected by the rotatable polygonal mirror toward the fixing device side, and rest parts of the laser beams are reflected by the rotatable polygonal mirror toward a side opposite from the fixing device side. Of the parts of the laser beams reflected by the rotatable polygonal mirror toward the fixing device side, the laser beam reflected toward the reflecting member provided at a position remotest from the rotatable polygonal mirror travels downward relative to a horizontal direction. A rotational axis of the rotatable polygonal mirror is inclined relative to a vertical direction.