Riso Kagaku Corporation

Kosai Adachi

Masakazu Miyata

Tomoko Nagano

Susumu Oshio

Yasuhiro Fujimoto

A cut sheet feeder for use with an image forming apparatus, comprising: a sheet feed mechanism for picking up stacked cut sheets one at a time from a single sheet feed position and for feeding each sheet to an image recording portion; a sheet feed unit which is vertically movable relative to the sheet feed mechanism, to which a cassette containing cut sheets may be attached in a detachable manner, and which has a cutout portion corresponding to the position of the sheet feed mechanism; a sheet feed table which is vertically movable within the sheet feed unit and which carries a large number of cut sheets; and a sheet feed controller for lifting, in a sheet feed mode based on the cassette, at least the sheet feed unit up to a position where the cut sheets in the cassette reach the sheet feed position; and for lifting, in a sheet feed mode based on the sheet feed table, the sheet feed unit to a position where the top of the unit comes above the sheet feed position with the cutout portion of the unit letting the sheet feed mechanism pass therethrough unchecked, thereby lifting the sheet feed table up to a position where the cut sheets on the sheet feed table reach the sheet feed position.

Cut sheet feeder for image forming apparatus

A cut sheet feeder for use with an image forming apparatus is formed of a sheet feed mechanism for picking up stacked cut sheets one at a time from a single sheet feed position and for feeding each sheet to an image recording portion; a sheet feed unit which is vertically movable relative to the sheet feed mechanism and to which a cassette containing cut sheets may be attached in a detachable manner; a sheet feed table which is vertically movable within the sheet feed unit and which carries a large number of cut sheets; a cassette presence detection device for detecting the presence and absence of a cassette on the sheet feed unit and for outputting a signal indicating either the presence or the absence of the cassette; a power switch for starting and stopping the cut sheet feeder; and a mode establishment device. A cassette feed mode involving the cassette for minority sheet feed is established if the detection signal from the cassette presence detection device indicates the presence of the cassette when the power switch is turned on, and a table feed mode involving the sheet feed table for majority sheet feed is established if the detection signal from the cassette presence detection device indicates the absence of the cassette.

A cut sheet feeder for use with an image forming apparatus, is formed of: a sheet feed mechanism for picking up stacked cut sheets one at a time from a single sheet feed position and for feeding each sheet to an image recording portion; a sheet feed unit which is vertically movable relative to the sheet feed mechanism and to which a cassette containing cut sheets may be attached in a detachable manner; a sheet feed table which is vertically movable within the sheet feed unit and which carries a large number of cut sheets; a plurality of detectors for detecting the positions of the sheet feed unit, the sheet feed table and the cut sheets relative to the sheet feed position; and a sheet overload detector. The overload is detected by the detectors with respect to the relative position between the sheet feed unit and the sheet feed table with reference to the sheet feed position. A mode controller controls the vertical movement of the sheet feed unit and the sheet feed table and stops the vertical movement when the detection signal from the sheet overload detector is admitted.

A cut sheet feeder for use with an image forming apparatus includes a sheet feed mechanism and a sheet feed unit mechanism. The sheet feed mechanism picks up stacked cut sheets one at a time from a predetermined position and feeds each sheet to an image recording portion. The sheet feed unit is vertically movable relative to the sheet feed mechanism and has a first sheet feed table. The first sheet feed table is located in an upper part of the sheet feed unit and includes a cutout portion for avoiding interference with the sheet feed mechanism when the first sheet feed table moves vertically in combination with the sheet feed unit. A second sheet feed table is located in a lower part of the sheet feed unit and vertically movable relative to the sheet feed unit.

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Tsukuba, Japan

Kosai Adachi