Abstract: An interchangeable lens assembly includes a plurality of lens-side claw portions configured to enable engagement with a plurality of camera-side claw portions, and a lock pin concave portion in which a lock pin is inserted. Furthermore, ?1 is an angle formed by a line passing through a fifth lens-side end and an optical axis, and a line passing through a center of a lock pin concave portion and the optical axis, and ?2 is an angle formed by a line passing through a fourth lens-side end and the optical axis, and a line that passes through the center of the lock pin concave portion and the optical axis. In the above, ?1 and ?2 satisfy a predetermined conditional expression.

Abstract: An interchangeable lens assembly includes a plurality of lens-side claw portions and a lock pin concave portion. Furthermore, internal angles of a quadrangle formed by connecting a center of a first lens-side claw portion, a center of a second lens-side claw portion, a center of a third lens-side claw portion, and a center of the lock pin concave portion satisfies a predetermined condition.

Abstract: An accessory configured to be detachably mountable to an image pickup apparatus including a first mount portion including first bayonet claw portions and first terminals, the accessory including a second mount portion including second bayonet claw portions configured to enable engagement with the first bayonet claw portions, and second terminals configured to enable contact with the first terminals, in which the second terminals are provided at positions that are different from positions of the second bayonet claw portions, and wherein half lines that extends from a central axis of the second mount portion and passes through second terminals that are used in communication between the image pickup apparatus and the accessory, all pass through a predetermined second bayonet claw portion.

Abstract: An accessory configured to be detachably mountable to an image pickup apparatus including a first mount portion including first bayonet claw portions, and first terminals, the accessory including a second mount portion including second bayonet claw portions configured to enable engagement with the first bayonet claw portions, and second terminals configured to enable contact with the first terminals, in which the second terminals are provided at positions that are different from positions of the second bayonet claw portions, and wherein, a half line that extends from a central axis of the second mount portion and passes through a second terminal that determines whether an optical apparatus is mounted on the image pickup apparatus or not, passes through a predetermined second bayonet claw portion.

Abstract: An accessory configured to be detachably mountable to an image pickup apparatus including a first mount portion including first bayonet claw portions and first terminals, the accessory including a second mount portion including second bayonet claw portions configured to enable engagement with the first bayonet claw portions, and second terminals configured to enable contact with the first terminals, in which the second terminals are provided at positions that are different from positions of the second bayonet claw portions, and wherein half lines that extends from a central axis of the second mount portion and passes through second terminals that are used in communication between the image pickup apparatus and the accessory, all pass through a predetermined second bayonet claw portion.

Abstract: An accessory configured to be detachably mountable to an image pickup apparatus including a first mount portion including first bayonet claw portions, and first terminals, the accessory including a second mount portion including second bayonet claw portions configured to enable engagement with the first bayonet claw portions, and second terminals configured to enable contact with the first terminals, in which the second terminals are provided at positions that are different from positions of the second bayonet claw portions, and wherein, a half line that extends from a central axis of the second mount portion and passes through a second terminal that determines whether an optical apparatus is mounted on the image pickup apparatus or not, passes through a predetermined second bayonet claw portion.

Abstract: An optical element unit is insertable into and removable from an opening portion provided in an optical apparatus and a first portion with a first inner diameter and a second portion with a second inner diameter smaller than the first inner diameter are disposed inside of the opening portion. The optical element unit has a third portion with a first outer diameter and a fourth portion with a second outer diameter smaller than the first outer diameter, wherein the first outer diameter is greater than the second inner diameter. Therefore, when the optical element unit is inserted into the opening portion in a reverse way, the third portion contacts with the second portion so that the optical element cannot be fully inserted into the opening portion.

Abstract: An accessory mountable on and demountable from a camera body includes a first mount unit including a plurality of first bayonet claw portions, a second mount unit including a plurality of second bayonet claw portions configured to be engaged with the plurality of first bayonet claw portions, an elastic member configured to contact the camera body when the accessory is mounted on the camera body, and a holding member configured to hold the elastic member. The holding member is provided with a recessed portion which a part of the elastic member can enter when the accessory is mounted on the camera body.

Abstract: An interchangeable lens assembly includes a plurality of lens-side claw portions configured to enable engagement with a plurality of camera-side claw portions, and a lock pin concave portion in which a lock pin is inserted. Furthermore, ?1 is an angle formed by a line passing through a fifth lens-side end and an optical axis, and a line passing through a center of a lock pin concave portion and the optical axis, and ?2 is an angle formed by a line passing through a fourth lens-side end and the optical axis, and a line that passes through the center of the lock pin concave portion and the optical axis. In the above, ?1 and ?2 satisfy a predetermined conditional expression.

Abstract: An accessory configured to be detachably mountable to an image pickup apparatus including a first mount portion including first bayonet claw portions, and first terminals, the accessory including a second mount portion including second bayonet claw portions configured to enable engagement with the first bayonet claw portions, and second terminals configured to enable contact with the first terminals, in which the second terminals are provided at positions that are different from positions of the second bayonet claw portions, and wherein, a half line that extends from a central axis of the second mount portion and passes through a second terminal that determines whether an optical apparatus is mounted on the image pickup apparatus or not, passes through a predetermined second bayonet claw portion.

Abstract: An interchangeable lens assembly includes a plurality of lens-side claw portions and a lock pin concave portion. Furthermore, internal angles of a quadrangle formed by connecting a center of a first lens-side claw portion, a center of a second lens-side claw portion, a center of a third lens-side claw portion, and a center of the lock pin concave portion satisfies a predetermined condition.

Abstract: An accessory configured to be detachably mountable to an image pickup apparatus including a first mount portion including first bayonet claw portions and first terminals, the accessory including a second mount portion including second bayonet claw portions configured to enable engagement with the first bayonet claw portions, and second terminals configured to enable contact with the first terminals, in which the second terminals are provided at positions that are different from positions of the second bayonet claw portions, and wherein half lines that extends from a central axis of the second mount portion and passes through second terminals that are used in communication between the image pickup apparatus and the accessory, all pass through a predetermined second bayonet claw portion.

Abstract: A holding apparatus which holds an optical element, the apparatus including: a lens barrel having an axis; and an annular pressing member configured to be screwed with the lens barrel and press the optical element against the lens barrel in a direction of the axis, wherein an engaging portion is formed in the pressing member, the engaging portion being to engage with a fastening tool for fastening the pressing member, at least a part of the engaging portion being formed, in the direction, in a region of the pressing member where the pressing member is screwed with the lens barrel.

Abstract: In a toner image fixing device, there are provided an endless belt being looped up around a heating roller and a conveyance roller, a pressure roller for pressing a sheet having a toner image onto the heating roller with the endless belt intervening between the pressure roller and the heating roller. A sensor is disposed inside the loop of the belt so as to come in contact with the heating roller, for detecting the temperature of the heating roller. The fixing temperature for the toner image is controlled on the basis of the temperature of the heating roller detected by the sensor. A first nip region is formed on a pressing portion located between the heating roller and the fixing roller. A second nip region is formed between the belt and the fixing roller, continuing from the first nip region but without contacting the heating roller.

Abstract: An electrophotographic image forming method is disclosed. The method comprises the steps of developing an electrostatic image formed on an image-forming member with a particulate toner for forming a toner image and transferring said toner image onto a receiving material, in which the image-forming member has a surface-improving layer comprised principally of amorphous silicon, and the toner has a weight average particle size within the range of from 1 .mu.m to 6 .mu.m and contains a constituent having a weight average particle size of not more than 5 .mu.m which accounts for not less than 20% by weight of the whole amount of the toner. An electrophotographic copy bearing a high-resolution and high-quality image can be stably obtained by this method.

Abstract: Disclosed is a photoreceptor which comprises a charge generation layer composed of at least one compound selected from the group consisting of amorphous hydrogenated silicon, amorphous fluorinated silicon and amorphous hydrofluorinated silicon, a charge transport layer formed on a lower surface of said charge generation layer and composed of at least one compound selected from the group consisting of amorphous hydrogenated silicon nitride, amorphous fluorinated silicon nitride, amorphous hydrofluorinated silicon nitride, amorphous hydrogenated silicon carbide, amorphous fluorinated silicon carbide and amorphous hydrofluorinated silicon carbide, and a substrate, wherein said charge transport layer contains oxygen within the range of from 50 atomic ppm to 5 atomic % based on the total atoms of silicon, nitrogen and carbon.

Abstract: An electrophotographic photoreceptor comprising a photosensitive layer comprisingat least one compound selected from the group consisting of hydrogenated amorphous silicon, fluorinated amorphous silicon,a surface modifying layer formed on the upper surface of said photosensitive layer comprising at least one compound selected from the group consisting of hydrogenated amorphous silicon carbide, fluorinated amorphous silicon carbide, hydrogenated and fluorinated amorphous silicon carbide, hydrogenated amorphous silicon nitride, fluorinated amorphous silicon nitride, and hydrogenated and fluorinated silicon nitride,a charge transport layer formed on the lower surface of said photosensitive layer comprising at least one compound selected from the group consisting of hydrogenated amorphous silicon carbide, fluorinated amorphous silicon carbide, and hydrogenated and fluorinated amorphous silicon carbide, the carbon content of said charge transport layer is within the range of 5 to 30 atomic % and said charge transp

Abstract: A photosensitive member wherein a charge transporting layer, a charge generating layer, and a surface modifying layer are laminated on a retainer. The charge transporting layer is prepared from one selected from a group of a-SiC:H, a-SiC:F, a-SiC:H:F, a-SiN:H, a-SiN:F, and a-SiN:H:F, the charge generating layer is prepared from one selected from a group of a-Si:H, a-Si:F and a-Si:H:F; and the surface modifying layer is prepared from one selected from a group of a-SiC:H, a-SiC:F, a-SiC:H:F, a-SiN:H, a-SiN:F and a-SiN:H:F. The surface modifying layer contains 1.about.50 atomic % of oxygen, 100 atomic % in total of Si, C (or N) and 0 atoms.

Abstract: A photoreceptor comprising a support bearing thereon a charge transport layer comprising one selected from the group consisting of a--SiC:H, a--SiC:F and a--SiC:H:F, a charge generating layer comprising one selected from the group consisting of a--SiH, a--SiF and a SiH:F, an a--Si type surface modifying layer containing one selected from the group consisting of N, O and C, and an a--Si type interlayer containing at least one selected from the group consisting of N, O and C, the content of said at least one of N, O and C in said interlayer being less than in said surface modifying layer, said interlayer being interposed between said charge generating layer and said surface modifying layer.

Abstract: A process for producing a photoreceptor is disclosed. A gaseous compound of the constituent materials of the photoreceptor is decomposed by glow discharge in the presence of a metal, thereby forming a constituent layer containing atoms and or ions of the metal.