An image forming apparatus is operable in a normal image forming mode and an uneven lubrication detecting mode, and includes: an image carrier; a lubricant applying device that applies lubricant to the image carrier; and a processor that detects uneven lubrication on a surface of the image carrier in the uneven lubrication detecting mode in which an amount of the lubricant applied to the image carrier is increased to exceed an amount of the lubricant applied in image forming.

To reduce the influence of a coupling pin that fixes a shaft to a photoreceptor drum on rotation of a photoreceptor drum. To provide photoreceptor device including: a photoreceptor drum having an insertion hole formed along a lengthwise direction; and a flange that is provided at a lengthwise end portion of the photoreceptor drum and has a through hole formed thereon at a position to overlap the insertion hole, wherein the flange has a first protruding portion and a second protruding portion that: are provided on an end surface at which the through hole is provided and around the through hole; and protrude from the end surface, the first protruding portion has a first opening at a position facing the through hole, and the second protruding portion is provided at a position opposite to the first opening across a center of the through hole on the end surface.

A drum cartridge attachable to and detachable from a main body of an image forming apparatus includes a cleaning frame, a photosensitive drum rotatably supported by the cleaning frame, and an opening provided in the cleaning frame and configured to expose the photosensitive drum. In a factory default state of the drum cartridge, handling caution information is printed in at least part of a region of a surface of the photosensitive drum, the region being exposed from the opening.

In an electrophotographic photosensitive member, a circumferential surface has concave portions that are independent one another; each of the concave portions has an opening, a contour of the opening has an apex having an angle α of more than 0° and 90° or less on at least an upstream side of a rotational direction of the electrophotographic photosensitive member, and has a largest width in an axial direction of the electrophotographic photosensitive member of 20 μm or more and 80 μm or less, a width of the contour in the axial direction of the electrophotographic photosensitive member decreasing from a portion having the largest width toward the apex, when viewing each of the concave portions in the axial direction, each of the concave portions has a depth that decreases from a deepest point of each of the concave portions toward the apex.

An image forming apparatus (1) includes photosensitive drums (41y, 41c, 41m, and 41k), static eliminators (45y, 45c, 45m, and 45k), transfer rollers (54y, 54c, 54m, and 54k), a power source (55a) for transfer, and load resistors (47y, 47c, 47m, and 47k). The static eliminators (45y, 45c, and 45m) perform static elimination on adjacently upstream or downstream photosensitive drums (41y, 41c, 41m, and 41k) in a movement direction of a transfer target. The transfer rollers (54y, 54c, 54m, and 54k) are disposed opposite to the respective photosensitive drums (41y, 41c, 41m, and 41k). The power source (55a) for transfer applies potential to the transfer rollers (54y, 54c, 54m, and 54k). The load resistors (57y, 57c, 57m, and 57k) are respectively connected in parallel to one another and in series between the power source (55a) for transfer and the respective transfer rollers (54y, 54c, 54m, and 54k).

In a first image formation mode, an image is formed with a first development contrast C1 and a specific dot pattern is formed with a second development contrast C2, which is lower than the first development contrast C1; in a second image formation mode, an image is formed with a third development contrast C3 and a specific dot pattern is formed with a fourth development contrast C4, which is lower than the third development contrast C3; and when ΔC1 (=C2/C1) denotes a ratio between the second development contrast C2 and the first development contrast C1, and ΔC2 (=C4/C3) denotes a ratio between the fourth development contrast C4 and the third development contrast C3, ΔC2<ΔC1 is satisfied.

In a photosensitive drum, a drum flange is press-fitted to each end of a drum element tube. The drum flange includes a flange facing the drum element tube, and a press-in boss formed on a drum-facing surface side of the flange and press-fitted to the inner circumferential side of the drum element tube. The outer circumferential surface of the press-in boss is configured so that partial cylindrical surfaces to be in contact with the inner circumferential surface of the drum element tube and oppositely-facing partial cylindrical surfaces not to be in contact with the inner circumferential surface of the drum element tube are alternately formed along the circumferential direction. First openings formed to penetrate at least a part of the press-in boss are respectively provided on the proximal end side of the partial cylindrical surfaces in the press-in boss.

An image forming apparatus which forms an image on a medium on the basis of an input image signal includes: an image carrier configured to carry a developed toner image transferred to the medium on a photoreceptor layer; a contact member arranged so as to be in contact with the surface of the photoreceptor layer; a trace pattern generating unit configured to generate a trace pattern indicating specific information on the image forming apparatus; a composition unit configured to add the trace pattern to the image signal; and an acquiring unit configured to acquire information on the thickness of the photoreceptor layer of the image carrier, wherein the trace pattern is used for arranging a plurality of image areas at respective positions, and the trace pattern generating unit is configured to generate the trace pattern with the image area whose size is reduced in accordance with reduction of the thickness of the photoreceptor layer.

An organic photoconductor includes a cylindrical body having a surface on which an electrostatic latent image is to be formed, and an optical tag provided on an outer circumferential surface of the cylindrical body. The organic photoconductor may be included in a development cartridge for an image forming apparatus.

An image forming apparatus includes: a photosensitive drum; a process frame from which the photosensitive drum is detachable; an apparatus body from which the process frame is removable; a drum shaft including one end constituting a free end, and another end supported by the apparatus body, and transmitting rotational driving force to the photosensitive drum; and a fixing member configured to stop movement of the photosensitive drum, wherein the one end of the drum shaft is configured to penetrate through and protrude from the photosensitive drum, the photosensitive drum includes a first annular protruding portion, the process frame includes a bearing part, the fixing member includes a second annular protruding portion, the one end of the drum shaft is pivotally supported by the fixing member, and the first annular protruding portion of the photosensitive drum is pivotally supported by the second annular protruding portion of the fixing member.