Abstract: An image forming apparatus includes an image forming device to form an image on a sheet and a sheet feeding unit to feed the sheet to the image forming device. The sheet feeding unit includes an endless, dielectric belt disposed facing an upper surface of a sheet stack to contact and attract an uppermost sheet to the surface thereof and feed the sheet in the sheet feeding direction, and an electric potential pattern forming unit to form an electric potential pattern on the surface of the dielectric belt. The electric potential pattern has multiple potential holding sections of identical absolute values and opposite polarities disposed adjacent to each other at a uniform pitch. The electric potential pattern forming unit forms the electric potential pattern to have equal numbers of positive potential holding sections and negative potential holding sections.

Abstract: A sheet feeder attracts an uppermost sheet of a sheet stack of a plurality of stacked sheets, and feeds the sheet in a sheet feeding direction. The sheet feeder includes an endless belt, a charging device, and a control device. The endless belt is made of a dielectric material, passes over upstream and downstream rollers, and is disposed above the sheet stack to face the sheet stack. The charging device applies an alternating voltage to an outer circumferential surface of the endless belt to form thereon alternating charge patterns. The control device separately controls the respective rotation states of the upstream and downstream rollers to make a sheet contact surface of the endless belt go slack in sheet attraction and make the sheet contact surface of the endless belt taut with tension into a substantially flat surface in sheet conveyance.

Abstract: A vacuum pump includes a casing having an inlet port and an outlet port, a stator portion provided inside the casing and a rotor portion having a shaft rotatably supported inside the casing and a rotor disposed on the shaft and provided with a gas transfer mechanism that transfers a gas from the inlet port to the outlet port. The rotor portion is arranged with a predetermined clearance between the rotor portion and the stator portion. A motor rotates the shaft. Vibration detection disposed in the stator portion detects vibrations by converting vibration amplitude to an electric signal. Contact detection judges an occurrence of contact between the stator portion and the rotor portion when, in the vibration detected by the vibration detection, an amplitude in frequency of a specific vibration caused by contact between the stator portion and the rotor portion exceeds a predetermined threshold value.

Abstract: A sheet separation/conveyance device that is included in an image forming apparatus includes an attraction/separation unit including an endless belt on which a region of attraction and a region of no attraction that divides the region of attraction are aligned in a sheet conveying direction, the endless belt configured to hold an uppermost sheet placed on top of a sheet stack contained in an image forming apparatus by using electrostatic attraction, a charger configured to charge a surface of the endless belt, the charger including an electrode configured to contact the surface of the endless belt due to a supply of a voltage and a detector configured to detect a charged condition on the surface of the endless belt based on a detection result obtained when the electrode contacts the endless belt, and a sheet conveying unit configured to convey the uppermost sheet held by the electrostatic attraction.

Abstract: A sheet feeding device that can be incorporated in an image forming apparatus includes a sheet feeder including a belt unit including an attraction belt facing a sheet stack and first and second tension rollers to keep the attraction belt taut, and a side holder to rotatably support the belt unit about the first tension roller that serves as a pivot of the sheet feeder being disposed upstream from the second tension roller in the sheet conveyance direction, a contact and separation drive unit to swing the sheet feeder to make the attraction belt contact with and separate from the sheet stack, and a swing range adjuster to adjust a range of swing of the belt unit with respect to the side holder between contact and separation of the attraction belt with respect to the sheet stack, according to a predetermined condition.

Abstract: Provided are a stator blade assembly advantageous for improving the evacuation performance by shortening the evacuation time, and an exhaust pump provided with such a stator blade assembly. Inner and outer stator blade bases of a plurality of stator blades are supported by frames. A projecting portion protruding from the frame supporting the inner stator blade base, or from the frame supporting the outer stator blade base, or from both of the frames is provided in a gap in the vicinity of the inner or outer stator blade base between one of the supported stator blades and the stator blade transversely adjacent thereto.

Abstract: A sheet conveyor incorporated in an image forming apparatus includes an attraction/separation unit including an attraction belt, a first tension roller, and a second tension roller, a support member to support the attraction/separation unit, a roller drive unit to rotate one of the first and second tension rollers, a charging member to uniformly charge a surface of the attraction belt, a mechanism to swing the attraction/separation unit to move the attraction belt reciprocally about the support member between a sheet attraction position and a sheet conveyance position being located farther from the sheet stack than the sheet attraction position, and a pressing member disposed inside a loop of the attraction belt to press the attraction belt at the sheet attraction position toward the sheet stack and separating from the attraction belt at the sheet conveyance position.

Abstract: A fixing device includes a fixing member, a pressing member, a contacting member fixed in an interior of the fixing member, and a heating unit that emits infrared ray. A mechanism concentrates the infrared ray emitted by the heating unit into a nip portion between the fixing member and the pressing member and into an area narrower than a width of the nip portion.

Abstract: A rotating body of a vacuum pump is partially constituted by a fiber-reinforced plastic and configured to exhaust gas by rotation. A corrosion-resistant layer is provided on the fiber-reinforced plastic portion which is the base material of the rotating body. A high-emissivity layer having a higher emissivity than the corrosion-resistant layer is provided on the corrosion-resistant layer. Fixed members facing the rotating body of the vacuum pump are each provided with a high-emissivity layer having a higher emissivity than the base material of the fixed members on the surfaces facing the fiber-reinforced plastic portion of the rotating body.

Abstract: A sheet feeder includes a loading member, an attraction separation unit, and a control device. The loading member carries sheet materials. The attraction separation unit includes an endless dielectric belt, holding rollers, and an adjustment device. The endless belt attracts and holds the uppermost one of the sheet materials. The holding rollers holding the endless belt include upstream and downstream holding rollers. The upstream holding roller is rotated around a shaft of the downstream holding roller as the rotation axis in accordance with rotation of the downstream holding roller. The adjustment device provided to the upstream holding roller adjusts the movement range of the upstream holding roller in the height direction. The control device controls, in accordance with the type of sheet materials, an operation of lifting and lowering the loading member, to thereby allow the adjustment device to adjust the movement range of the upstream holding roller.

Abstract: A sheet feeder attracts an uppermost sheet of a sheet stack of a plurality of stacked sheets, and feeds the sheet in a sheet feeding direction. The sheet feeder includes an endless belt, a charging device, and a control device. The endless belt is made of a dielectric material, passes over upstream and downstream rollers, and is disposed above the sheet stack to face the sheet stack. The charging device applies an alternating voltage to an outer circumferential surface of the endless belt to form thereon alternating charge patterns. The control device separately controls the respective rotation states of the upstream and downstream rollers to make a sheet contact surface of the endless belt go slack in sheet attraction and make the sheet contact surface of the endless belt taut with tension into a substantially flat surface in sheet conveyance.

Abstract: A sheet feeder includes: an attraction separation unit including an attraction belt stretched between rollers and facing the upper surface of a sheet bundle to attract an uppermost sheet thereof, rotatably supported by a support member at a position upstream of the attraction belt in a sheet feeding direction, and supporting the rollers to be released from the support upon contact of the rollers with the uppermost sheet via the attraction belt; and a swing device for swinging the attraction separation unit around the support member as a pivot to move the attraction belt between an attraction position and a feed position more distant from the sheet bundle than the attraction position, and swinging, after the uppermost sheet has been attracted to the attraction belt at the attraction position, the attraction belt to the feed position to be rotated to feed the uppermost sheet.

Abstract: A sheet feeder attracts an uppermost sheet of a sheet stack of a plurality of stacked sheets, and feeds the sheet in a sheet feeding direction. The sheet feeder includes an endless belt, a charging device, and a control device. The endless belt is made of a dielectric material, passes over upstream and downstream rollers, and is disposed above the sheet stack to face the sheet stack. The charging device applies an alternating voltage to an outer circumferential surface of the endless belt to form thereon alternating charge patterns. The control device separately controls the respective rotation states of the upstream and downstream rollers to make a sheet contact surface of the endless belt go slack in sheet attraction and make the sheet contact surface of the endless belt taut with tension into a substantially flat surface in sheet conveyance.

Abstract: A sheet feeding device includes a sheet carrying unit and an attraction separation and conveyance device. The sheet carrying unit is configured to carry thereon a sheet stack. The attraction separation and conveyance device is configured to electrostatically attract the uppermost sheet of the sheet stack and separate and convey the uppermost sheet from the sheet stack, and is placed between the upstream end and the central position in a sheet conveying direction of the sheet stack located at a sheet carrying position and having a minimum sheet size compatible with the sheet feeding device.

Abstract: A sheet feeder includes: an attracting and separating device disposed above a leading end portion in a sheet-feeding direction of a sheet stack, attracting and holding an uppermost sheet of the sheet stack with electrostatic force and separating the uppermost sheet from the sheet stack, a sheet loading device carrying the sheet stack, and including a first bottom plate carrying a rear-side portion of the sheet stack and a second bottom plate separated from the first bottom plate and carrying the leading end portion of the sheet stack below the attracting and separating device; and a lifting device lifting and lowering the sheet loading device, and including a first lifting device lifting and lowering the first bottom plate and a second lifting device lifting and lowering the second bottom plate to move the leading end portion of the sheet stack toward and away from the attracting and separating device.

Abstract: A sheet feeding device includes a sheet carrying unit, an attraction separation device electrostatically attracting and separating an uppermost sheet from a sheet stack and including multiple rollers, an endless dielectric belt stretched over the multiple rollers, and an elastic member provided inside a loop of the belt to cause the endless dielectric belt to contact the uppermost sheet, a sheet conveying device, and a lifting and lowering device. The lifting and lowering device lifts the sheet stack to a lift position at which the uppermost sheet contacts with the attraction separation device, and the attraction separation device stands by for a predetermined time to attract the uppermost sheet and starts to convey the uppermost sheet after the predetermined time elapses in a state in which the sheet stack remains at the lift position.

Abstract: A sheet feeder includes: an attracting and separating device disposed above a leading end portion in a sheet-feeding direction of a sheet stack, attracting and holding an uppermost sheet of the sheet stack with electrostatic force and separating the uppermost sheet from the sheet stack, a sheet loading device carrying the sheet stack, and including a first bottom plate carrying a rear-side portion of the sheet stack and a second bottom plate separated from the first bottom plate and carrying the leading end portion of the sheet stack below the attracting and separating device; and a lifting device lifting and lowering the sheet loading device, and including a first lifting device lifting and lowering the first bottom plate and a second lifting device lifting and lowering the second bottom plate to move the leading end portion of the sheet stack toward and away from the attracting and separating device.

Abstract: A sheet conveying device includes an attractive separation unit and a contacting and separating device. The attractive separation unit includes an attraction belt arranged to face the upper surface of a sheet stack, two rollers that stretch the attraction belt taut, with the upstream-side roller in the sheet conveying direction supported to be movable in substantially upward and downward directions within a predetermined range with respect to the upper surface of the sheet stack, and a charging device which charges a surface of the attraction belt. The contacting and separating device swings the attractive separation unit to make the attraction belt come into contact with and separate from the sheet stack, with a fulcrum of the swing of the attractive separation unit set to a position upstream in the sheet conveying direction of the upstream-side roller in the sheet conveying direction.

Abstract: A sheet feeding device that is incorporatable in an image forming apparatus includes an endless belt disposed facing an upper surface of a sheet stack to convey sheets of the sheet stack forward in a first moving direction of a surface thereof, an attraction unit to attract an uppermost sheet of the sheet stack to the endless belt, a contact and separation unit to contact and separate the endless belt relative to the sheet stack, and a controller to cause the endless belt to contact or substantially contact the upper surface of the sheet stack to attract the uppermost sheet to the endless belt, perform a pre-separation operation in which the endless belt moves in a reverse direction that is opposite the sheet conveyance direction, and then perform a separating operation in which the endless belt separates from the sheet stack.

Abstract: An image forming apparatus includes an image forming device, a sheet feeding unit, a belt pressing member, and a moving unit. The sheet feeding unit includes an endless, dielectric belt to contact and attract the uppermost sheet to a surface thereof and feed in a sheet feeding direction, and an electric potential pattern forming unit to form an electric potential pattern on a surface of the dielectric belt. The moving unit moves the belt pressing member between a sheet attracting position and a sheet feeding position. The dielectric belt attracts the uppermost sheet at the sheet attracting position, the moving unit moves the belt pressing member to the sheet feeding position, and an entire flat portion of the dielectric belt feeds the uppermost sheet in the sheet feeding direction while carrying the uppermost sheet thereon as the dielectric belt rotates.