Ricoh Company, Ltd.

Yoshikuni Ishikawa

Kenji Ueda

Manabu Nonaka

Hiroshi Kajiyama

Toshiaki Takahashi

Masayuki Ueda

Shun Kobayashi

Yasuhiro Sagawa

Hiroyuki Watase

Yu Wakabayashi

Naoyuki Okamoto

Aki Ikeda

Hajime Nishida

Hideto Higaki

Tamiya Akimoto

Tetsutaro Yasuda

Kazunori Bannai

Yosuke Eguchi

Satoshi Kuno

Katsuhiko Miki

Tadashi Kusumi

Tsugunao Toyooka

A sheet feeder, which is incorporated in an image forming apparatus, includes an endless attraction belt that is rotatably disposed facing a top surface of a sheet stack, a belt charger to attract an uppermost sheet of the sheet stack, and a sheet separator to press the attraction belt against the sheet stack, bend a contact region to which the uppermost sheet is attracted and contacted to the attraction belt, and separate the uppermost sheet from a subsequent sheet or other sheet of the sheet stack. In this configuration, a curvature of a contact surface of the sheet separator with respect to the attraction belt is changeable.

Sheet feeder and image forming apparatus incorporating same

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.

Sheet conveyor and image forming apparatus incorporating same

A sheet conveying device, that can be included in an image forming apparatus, includes a first conveying unit to convey a sheet in a first direction, a second conveying unit disposed on a downstream side of the first conveying unit to convey the sheet in a second direction, and a first path formed between the first and second conveying units. At least the second conveying unit has a holding section to hold and convey the sheet. The sheet conveying device further includes a belt conveying unit disposed along an outer side of the first path and includes a belt to convey the sheet toward the holding section. The belt is stretched around a first belt holding and rotating member and a second belt holding and rotating member disposed on an upstream side of the second conveying unit in the second direction.

Sheet conveying device, and image forming apparatus including same

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.

Sheet separation/conveyance device and image forming apparatus incorporating same

A sheet feeder includes an attraction separation unit including an attraction belt facing the upper surface of a stacked sheet bundle to attract an uppermost sheet thereof, and rotatably supported by a support member at a position upstream of the attraction belt in a sheet feeding direction; and a swing device for swinging the attraction separation unit around the support member as a fulcrum to move the attraction belt between an attraction position and a feed position more distant from the sheet bundle than the attraction position is. The swing device includes a first drive transmitting portion attached to a downstream end portion of the attraction separation unit and a second drive transmitting portion attached to the body of the sheet feeder and connected with the first drive transmitting portion. The first drive transmitting portion and the rack connect to swing the attraction separation unit.

Sheet feeder and image forming apparatus

An inkjet printer includes a movable conveyance belt, a first charging device, and a second charging device. Upon the conveyance belt, a recording medium is placed and conveyed at a given conveyance speed in a longitudinal, conveyance direction of the belt. The first charging device is disposed in contact with the belt while supplied with a first alternating current voltage to create a first electrified portion in the conveyance belt where positive and negative electric charges are arranged alternately with each other in the conveyance direction for electrostatically attracting the recording medium to the belt. The second charging device is disposed adjacent the belt to contact the recording medium conveyed on the belt while supplied with a second alternating current voltage to create a second electrified portion in the recording medium for cancelling an electric field originating from the first electrified portion of the belt.

Inkjet printer

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.

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.

Sheet feeding device and image forming apparatus incorporating same

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.

Sheet feeder and image forming apparatus using the same

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.

An attachment assist device includes an engagement member provided in one of a main body and a retractable unit, a catch portion provided in the other of the two, to engage the engagement member when the retractable unit is positioned at a drawing start position, and a drawing unit provided in the main body, to draw the retractable unit to a drawing completion position in the main body against multiple resistive forces acting on the retractable unit. On a projection plane on which the retractable unit is projected in an attachment direction, an engagement position where the engagement member engages the catch portion is disposed inside a rectangular area defined by two opposing corners respectively positioned at points of action of two of the multiple resistive forces acting on the retractable unit while the retractable unit moves from the drawing start position to the drawing completion position.

Attachment assist device and image forming apparatus including same

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.

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Tokyo, Japan

Yoshikuni Ishikawa