Abstract: An electrophotographic photoreceptor includes a conductive base body and a multilayered photosensitive layer disposed on the conductive base body and including a charge generation layer and a charge transport layer, wherein the charge transport layer is an uppermost surface layer and contains a charge transport material, a polyester resin, and a compound (T) represented by Formula (T) below, the polyester resin includes a polyester resin (1) including at least one selected from the group consisting of a diol unit (P1) represented by Formula (P1), a diol unit (P2) represented by Formula (P2), a diol unit (P3) represented by Formula (P3), a diol unit (P5) represented by Formula (P5), and a diol unit (P6) represented by Formula (P6), the polyester resin (1) further includes a unit including a biphenyl skeleton, and end groups of the polyester resin (1) do not include fluorine atoms.

Abstract: According to one embodiment, a magnetic recording medium includes a first magnetic region, a second magnetic region, a third magnetic region, a fourth magnetic region, and a fifth magnetic region. The second magnetic region is provided between the fifth magnetic region and the first magnetic region in a first direction from the fifth magnetic region to the first magnetic region. The third magnetic region is provided between the fifth magnetic region and the second magnetic region in the first direction. The fourth magnetic region is provided between the fifth magnetic region and the third magnetic region in the first direction. A first composition ratio of a first Pt atomic concentration to a first Co atomic concentration in the first magnetic region is higher than a second composition ratio of a second Pt atomic concentration to a second Co atomic concentration in the second magnetic region.

Abstract: An electrophotographic photoreceptor includes a conductive base body and a multilayered photosensitive layer disposed on the conductive base body and including a charge generation layer and a charge transport layer, wherein the charge transport layer is an uppermost surface layer and contains a charge transport material, a polyester resin, and a compound (T) represented by Formula (T) below, the polyester resin includes a polyester resin (1) including at least one selected from the group consisting of a diol unit (P1) represented by Formula (P1), a diol unit (P2) represented by Formula (P2), a diol unit (P3) represented by Formula (P3), a diol unit (P5) represented by Formula (P5), and a diol unit (P6) represented by Formula (P6), the polyester resin (1) further includes a unit including a biphenyl skeleton, and end groups of the polyester resin (1) do not include fluorine atoms.

Abstract: According to one embodiment, a magnetic head includes a first magnetic pole, a second magnetic pole, and a magnetic element provided between the first and the second magnetic poles. The magnetic element includes first to fifth magnetic layers, and first to sixth non-magnetic layers. The fifth magnetic layer includes a first element and at least one of Fe, Co or Ni. The first element includes at least one selected from the group consisting of Cr, V, Mn, Ti, N and Sc. The fifth non-magnetic layer includes at least one selected from the group consisting of Ru, Ir, Ta, Rh, Pd, Pt and W. The sixth non-magnetic layer includes at least one selected from the group consisting of Cu, Au, Cr, Al, V and Ag.

Abstract: According to one embodiment, a magnetic head includes a first magnetic pole, a second magnetic pole, and a magnetic element provided between the first and the second magnetic poles. The magnetic element includes first to fifth magnetic layers. A differential electric resistance of the magnetic element when a voltage between the first magnetic pole and the second magnetic pole being changed includes a first positive peak and a second positive peak. The voltage corresponding to the first positive peak is a first positive peak voltage. The voltage corresponding to the second positive peak is a second positive peak voltage. The second positive peak voltage is higher than the first positive peak voltage. An element voltage applied between the first magnetic pole and the second magnetic pole in a recording operation is higher than the second positive peak voltage.

Abstract: According to one embodiment, a magnetic head includes a first magnetic pole, a second magnetic pole, and a magnetic element provided between the first and the second magnetic poles. The magnetic element includes first to fourth magnetic layers, and first to fifth non-magnetic layers. The fourth magnetic layer includes a first element and at least one of Fe, Co or Ni. The first element including at least one selected from the group consisting of Cr, V, Mn, Ti, N and Sc. The fourth non-magnetic layer including at least one selected from the group consisting of Cu, Au, Cr, Al, V and Ag. The fifth non-magnetic layer includes at least one selected from the group consisting of Cu, Au, Cr, Al, V and Ag.

Abstract: An electrophotographic photoreceptor includes a conductive substrate, and a lamination type photosensitive layer disposed on the conductive substrate and including a charge generation layer and a charge transport layer, in which the charge transport layer contains a polyester resin (1) having a dicarboxylic acid unit (A) represented by Formula (A) and a diol unit (B) represented by Formula (B), and an amount of a diol represented by Formula (1) in the charge transport layer is 10 ppm or less, in Formula (A), n1 represents 1, 2, or 3, n1 pieces of m1's each independently represent 0, 1, 2, 3, or 4, m1 pieces of Ra1's each independently represent an alkyl group having 1 or more and 10 or less carbon atoms, an aryl group having 6 or more and 12 or less carbon atoms, or an alkoxy group having 1 or more and 6 or less carbon atoms, in Formula (B), Rb1 and Rb2 each independently represent a hydrogen atom, an alkyl group having 1 or more and 20 or less carbon atoms, an aryl group having 6 or more and 12 or less

Abstract: An electrophotographic photoreceptor contains a conductive substrate, and a lamination type photosensitive layer disposed on the conductive substrate and including a charge generation layer and a charge transport layer, in which the charge transport layer contains a charge transport material, at least one of a polyester resin or a polycarbonate resin that has a constitutional unit containing biphenyl represented by Formula (1), and an aromatic dicarboxylic acid represented by Formula (2), in Formula (1), j represents an integer of 0 or greater and 4 or less, j pieces of R11's each independently represent a methyl group or an ethyl group, k represents an integer of 0 or greater and 4 or less, and k pieces of R12's each independently represent a methyl group or an ethyl group, in Formula (2), p represents an integer of 0 or greater and 4 or less, p pieces of R21's each independently represent a methyl group or an ethyl group, q represents an integer of 0 or greater and 4 or less, q pieces of R22's each in

Abstract: An electrophotographic photoconductor includes a conductive substrate, and a photoconductive layer, in which an outermost surface layer contains a binder resin, a charge transporting material, fluorine-containing resin particles, and an acidic compound, the number of carboxyl groups in the fluorine-containing resin particles is 0 or more and 30 or less per 106 carbon atoms of the fluorine-containing resin particles, and in a case where charging and exposure of the electrophotographic photoconductor are repeated 10,000 times under conditions of a charging potential of ?700 V and an exposure intensity of 5 mJ/m2, an absolute value |RP1?RP10000| of a difference between a residual potential RP1 after charging and exposure once and a residual potential RP10000 after charging and exposure 10,000 times is 25 V or less.

Abstract: An electrophotographic photoreceptor includes a conductive substrate, and a lamination type photosensitive layer disposed on the conductive substrate and including a charge generation layer and a charge transport layer, in which the charge transport layer contains a charge transport material, at least one of a polyester resin (PEz) or a polycarbonate resin (PCz) that has at least one of a structure (Z1) represented by Formula (Z1) or a structure (Z2) represented by Formula (Z2) at at least one terminal, and a resin (X) that has at least one of a unit (X1) represented by Formula (X1) or a unit (X2) represented by Formula (X2), a mass proportion of the resin (X) in a total amount of the polyester resin (PEz), the polycarbonate resin (PCz), and the resin (X) in the charge transport layer is 0.

Abstract: An electrophotographic photoreceptor includes a conductive substrate, and a lamination type photosensitive layer including a charge generation layer and a charge transport layer or a single layer type photosensitive layer that is a photosensitive layer disposed on the conductive substrate, in which the charge transport layer or the single layer type photosensitive layer is an outermost layer and contains a charge transport material and a binder resin containing a polyester resin having an aromatic ring, the charge transport layer or the single layer type photosensitive layer has an average thickness of 28 ?m or greater and 50 ?m or less, and a weight reduction ratio of the charge transport layer or the single layer type photosensitive layer from 30° C. to 175° C. in thermogravimetric analysis is 0.1% by mass or less.

Abstract: An electrophotographic photoreceptor includes a conductive substrate, and a lamination type photosensitive layer disposed on the conductive substrate and including a charge generation layer and a charge transport layer, in which the charge transport layer contains a charge transport material, a polyester resin, and a polycarbonate resin, and the polyester resin includes the following polyester resin (1), polyester resin (1): a polyester resin having at least one selected from the group including a diol unit (B3) represented by Formula (B3), a diol unit (B5) represented by Formula (B5), a diol unit (B6) represented by Formula (B6), a diol unit (B7) represented by Formula (B7), a diol unit (B8) represented by Formula (B8), a diol unit (B9) represented by Formula (B9), a diol unit (B10) represented by Formula (B10), and a diol unit (B11) represented by Formula (B11), in Formula (B3), Rb113 and Rb213 each independently represent a hydrogen atom, a linear alkyl group having 1 or more and 3 or less

Abstract: An electrophotographic photoreceptor includes a conductive substrate, and a lamination type photosensitive layer including a charge generation layer and a charge transport layer or a single layer type photosensitive layer that is a photosensitive layer disposed on the conductive substrate, in which the charge transport layer or the single layer type photosensitive layer is an outermost layer and contains a charge transport material, a polyester resin having a dicarboxylic acid unit (A) represented by Formula (A), and a compound that has a molecular weight of 255 or greater, has a phenol skeleton in which a primary carbon atom or a secondary carbon atom is bonded to one ortho position and a tertiary carbon atom or a quaternary carbon atom is bonded to the other ortho position, and has no linear alkylene structure having 4 or more carbon atoms.

Abstract: An electrophotographic photoreceptor includes a conductive substrate, and a lamination type photosensitive layer disposed on the conductive substrate and including a charge generation layer and a charge transport layer in this order, in which the charge transport layer contains at least one resin selected from a polyester resin or a polycarbonate resin, and in a case where a Martens hardness and an indentation hardness, which are acquired by an indentation test performed on the charge transport layer to a depth of 0.5 ?m, are respectively defined as HM (N/mm2) and nIT (N/mm2), Relational Equation (0) is satisfied, an elastic deformation modulus is 45% or greater and 70% or less, and a tensile elastic modulus of the charge transport layer is 2,300 MPa or greater and 5,000 MPa or less, nIT=a×HM?b(a=2±0.2,b=100±20).

Abstract: An electrophotographic photoreceptor includes a conductive substrate, and a lamination type photosensitive layer disposed on the conductive substrate and including a charge generation layer and a charge transport layer, in which the charge transport layer contains a polyester resin having a structure represented by Formula (1) at a terminal and a charge transport material, and in a case where a weight-average molecular weight Mw of the polyester resin is defined as A (×10,000), a value of a ratio M1/M2 of a mass M1 of the charge transport material to a mass M2 of an entire charge transport layer is defined as Cs, and an average thickness of the charge transport layer is defined as Ds (?m), expressions of 7?A?40, 0.28?Cs?0.55, 27?Ds?50, and 5.

Abstract: An electrophotographic photoreceptor includes a conductive substrate, an undercoat layer disposed on the conductive substrate, and a lamination type photosensitive layer disposed on the undercoat layer and including a charge generation layer and a charge transport layer, in which the charge transport layer contains a charge transport material and a polyester resin, and in a case where an average thickness of the charge transport layer is defined as As (?m) and an average thickness of the undercoat layer is defined as Bs (?m), expressions 27?As?50, 10?Bs?40, and 0.70?As/Bs?4.80 are satisfied.

Abstract: An electrophotographic photoreceptor includes a conductive substrate, and a lamination type photosensitive layer disposed on the conductive substrate and including a charge generation layer and a charge transport layer, in which the charge transport layer contains a charge transport material, at least one of a polyester resin that has a constitutional unit having an aromatic ring or a polycarbonate resin that has a constitutional unit having an aromatic ring, and a compound (1) represented by Formula (1) and having a melting point of 40° C. or higher, in Formula (1), Ar represents an aromatic ring that may have a substituent, L represents a single bond, an oxygen atom, or a sulfur atom, R represents an alkyl group having 1 or more and 10 or less carbon atoms, an aryl group having 6 or more and 20 or less carbon atoms, or an aralkyl group having 7 or more and 20 or less carbon atoms, and n represents an integer of 1 or greater.

Abstract: An image forming unit includes a photoreceptor and a charging member that comes into contact with a surface of the photoreceptor and charges the photoreceptor, in which the photoreceptor includes a conductive substrate, and a lamination type photosensitive layer disposed on the conductive substrate and including a charge generation layer and a charge transport layer, the charge transport layer contains at least one of a polyester resin that has a constitutional unit having an aromatic ring or a polycarbonate resin that has a constitutional unit having an aromatic ring, the charging member includes a support member and an elastic layer disposed on the support member, and the elastic layer has a storage elastic modulus G? of 5.0 MPa or less at a frequency of 100 Hz in dynamic viscoelasticity measurement under a temperature condition of 24° C.

Abstract: A gas control device includes a pump, a valve, a cuff, and a controller. The valve includes a first plate having a first vent hole and a first vent hole, a channel forming plate having an exhaust hole and an exhaust channel, a second plate having a second vent hole, and an edge separation plate. A manchette rubber tube in the cuff is joined to the periphery of the second vent hole in the second plate by an adhesive, and thus the valve is connected to the cuff. The exhaust hole is opened to the atmosphere. The pump includes a pump housing having a discharge hole and a discharge hole. The upper surface of the pump housing is joined to the bottom surface of the edge separation plate.

Abstract: An electrophotographic photoreceptor includes a conductive substrate, and a lamination type photosensitive layer disposed on the conductive substrate and including a charge generation layer and a charge transport layer, in which the charge transport layer contains a charge transport material and a polyester resin, and a mass proportion of a chemical substance (AA) represented by Formula (AA) in a total mass of the charge transport layer is 2,000 ppm or less. In Formula (AA), X represents an organic group, and mAA represents an integer.