Provided an electrophotographic electro-conductive member that can stably suppress an occurrence of fogging in an electrophotographic image. The member comprises a support having an electro-conductive outer surface, and an electro-conductive layer on the outer surface of the support, the electro-conductive layer having a matrix including a cross-linked product of a first rubber, and domains dispersed in the matrix, the domains each includes a cross-linked product of a second rubber and an electro-conductive particle, at least some of the domains is exposed to the outer surface of the electro-conductive member to constitute protrusions on an outer surface of the member, the outer surface of the electro-conductive member is constituted by the matrix and the domains exposed to the outer surface of the electrophotographic electro-conductive member, the electrophotographic electro-conductive member has an impedance of 1.0×10.sup.3Ω or more and 1.0×10.sup.8Ω or less, and some of the domains satisfy two specific requirements.

An electrophotographic photoreceptor includes a conductive substrate, an undercoating layer that is disposed on the conductive substrate, and a photosensitive layer that is disposed on the undercoating layer, in which the undercoating layer contains at least one perinone compound selected from the group consisting of the compounds represented by Formulas (1) and (2), and at least one acceptor compound selected from the group consisting of compounds represented by Formula (3) to (15) which are shown in the specification. ##STR00001##

A measurement device includes a measurement unit that measures a physical property of a measurement target by causing the measurement target to vibrate through an application of an ultrasonic wave, the measurement unit including a first mode that measures the physical property using a first burst wave sensitive in a first predetermined range of physical property values and a second mode that measures the physical property using a second burst wave sensitive in a second range of physical property values different from the first range, and a control unit that controls the measurement unit to execute at least one of the first mode and the second mode.

A photoconductive drum includes an elongated support element with a shaped charge generation layer. The layer extends from the support element at various thicknesses along a length thereof. Thicker charge generation portions provides denser optical densities compared to thinner portions allowing tailoring the photoconductive drum to compensate for imperfect optical scanning systems. A charge transport layer overcoats the charge generation layer. Optionally, an oxidation layer underlies the charge generation layer as does a protective overcoat overlying the charge transport layer. Various thicknesses and shapes of the charge generation layer are also disclosed.

A post-processing apparatus includes a binding device, a closing device, a driver, and a changeover switch. The binding device binds a sheet bundle. The closing device closes an entrance to a binding position at which the binding device binds the sheet bundle. The driver moves the closing device to a closing position to close the entrance. The switch performs switching to implement a state in which the binding device is able to bind the sheet bundle when the closing device moves to the closing position. The closing device includes an avoidance operation portion to move to the closing position to operate the switch, and a drive coupler coupled to the avoidance operation portion to move the avoidance operation portion to the closing position. A coupling state between the avoidance operation portion and the drive coupler is released when movement of the avoidance operation portion to the closing position is prevented.

There is provided a process cartridge detachably attachable to a main body of an electrophotographic apparatus, the process cartridge including: an electrophotographic photosensitive member and a charging member, in which when average local potential differences of calculated lengths in the electrophotographic photosensitive member is calculated based on a specific method, a maximum value of the average local potential difference is 2 V or more, the charging member includes a support and an electro-conductive layer, the electro-conductive layer has a matrix and domains dispersed in the matrix, a volume resistivity ρM of the matrix is at least 1.00×10.sup.5 times a volume resistivity ρD of the domain, and a specific calculated length S.sub.CP [μm] and a specific value relating a distance between the domains D.sub.ms [μm] satisfy S.sub.CP≥3×D.sub.ms.

There is provided a process cartridge detachably attachable to a main body of an electrophotographic apparatus, the process cartridge including: an electrophotographic photosensitive member and a charging member, in which when average local potential differences of calculated lengths in the electrophotographic photosensitive member is calculated based on a specific method, a maximum value of the average local potential difference is 2 V or more, the charging member includes a support and an electro-conductive layer, the electro-conductive layer has a matrix and domains dispersed in the matrix, a volume resistivity ρM of the matrix is at least 1.00×10.sup.5 times a volume resistivity ρD of the domain, and a specific calculated length S.sub.CP [μm] and a specific value relating a distance between the domains D.sub.ms [μm] satisfy S.sub.CP≥3×D.sub.ms.

An electrophotographic photoreceptor includes an electroconductive substrate; and a photosensitive layer that is formed on the electroconductive substrate and that contains an inorganic oxide and a lubricant resin which contains a polycarbonate resin having a siloxane structure therein or a polyarylate resin having a siloxane structure therein. When light having a wavelength of 780 nm is irradiated onto a slurry containing 20% by mass of the inorganic oxide in a predetermined solvent to provide an inorganic oxide slurry, the inorganic oxide slurry has a light transmittance that is 80% or more. The photosensitive layer may be a negatively-charged laminate-type photosensitive layer, a monolayer type photosensitive layer, or a positively-charged laminate-type photosensitive layer. The electrophotographic photoreceptor is less worn upon long-term use, allows no filming, and can realize stable images. A method for producing the electrophotographic photoreceptor and an electrophotographic apparatus including the electrophotographic photoreceptor are disclosed.

An electrophotographic photoreceptor includes a support, an undercoat layer placed on the support, a charge generation layer placed on the undercoat layer, and a charge transport layer placed on the charge generation layer. The undercoat layer contains titanium oxide particles surface-treated with an organosilicon compound that is at least one member selected from the group consisting of compounds represented by formulas (1) to (8) and a polyamide resin. The charge generation layer contains hydroxygallium phthalocyanine.

An electrophotographic photoreceptor, including a photosensitive layer formed on an electroconductive substrate. The photosensitive layer includes a charge-generating material and an electron-transporting material, and the electron-transporting material includes first and second electron-transporting materials. A difference in lowest unoccupied molecular orbital (LUMO) energy between the first electron-transporting material and the charge-generating material is in a range from 1.0 to 1.5 eV, and a difference in LUMO energy between the second electron-transporting material and the charge-generating material is in a range from 0.6 to 0.9 eV. A ratio of mass of the second electron-transporting material to a total of mass of the first electron-transporting material and the mass of the second electron-transporting material is in a range from 3 to 40%.