Sheet feeder and image forming apparatus
AssigneeRicoh Company, Ltd.
InventorMunehisa Fuda
Life of this patent
Estimating the term…
Abstract
A sheet feeder attracts a topmost sheet on a sheet conveyor belt as a conveying member and conveys the sheet toward an image forming unit in a subsequent step. The sheet feeder includes a vane rotation direction control unit that serves as a suction direction control unit controlling a direction in which a suction blower as an air suction unit sucks air to be reversed as a positive pressure generating unit that generates a positive pressure in a sheet suction unit. The vane rotation direction control unit controls the direction in which the suction blower sucks air to be reversed immediately after a feeding operation ends to generate the positive pressure in the sheet suction unit.
Claims15
A sheet feeder, comprising:
- a feed tray configured to contain a stack of sheets;
- an air blower near a topmost sheet on top of the sheets stacked in the feed tray;
- a sheet suction unit that sucks the topmost sheet on top of the sheets stacked in the feed tray by a negative pressure generated at a position facing a top surface of the topmost sheet;
- an air suction unit that is connected to the sheet suction unit via an air flow passage and that sucks air from a sheet suction unit side to generate the negative pressure in the sheet suction unit;
- a sheet conveying unit that includes a conveying member and that attracts the topmost sheet sucked by the sheet suction unit on the conveying member and conveys the topmost sheet toward a pair of carriage rollers located in a downstream side in a conveying direction and disposed parallel to the sheet conveying unit;
- and
- a positive pressure generating unit that generates a positive pressure in the sheet suction unit,
- the positive pressure generating unit includes:
- an air releasing mechanism that opens the air flow passage between the sheet suction unit and the air suction unit to atmosphere, and
- an air release control unit that controls the air releasing mechanism to be opened and closed,
- wherein when the feeding operations ends, the respective driving sources of the air blower, the air suction unit, the sheet conveying unit, and the pair of carriage rollers are stopped and the air release control unit immediately controls the air releasing mechanism to be opened.
An image forming apparatus, comprising:
- an image forming unit that forms an image on a sheet as a recording medium;
- and
- a sheet feeder that feeds the sheet to the image forming unit, the sheet feeder Including;
- a feed tray configured to contain a stack of sheets;
- an air blower near a topmost sheet on top of the sheets stacked in the feed tray;
- a sheet suction unit that sucks the topmost sheet on top of the sheets stacked in the feed tray by a negative pressure generated at a position facing a top surface of the topmost sheet;
- an air suction unit that is connected to the sheet suction unit via an air flow passage and that sucks air from a sheet suction unit side to generate the negative pressure in the sheet suction unit;
- a sheet conveying unit that includes a conveying member and that attracts the topmost sheet sucked by the sheet suction unit on the conveying member and conveys the topmost sheet toward a pair of carriage rollers located in a downstream side in a conveying direction and disposed parallel to the sheet conveying unit;
- and
- a positive pressure generating unit that generates a positive pressure in the sheet suction unit, the positive pressure generating unit includes:
- an air releasing mechanism that opens the air flow passage between the sheet suction unit and the air suction unit to atmosphere, and
- an air release control unit that controls the air releasing mechanism to be opened and closed,
- wherein when the feeding operations ends, the respective driving sources of the air blower, the air suction unit, the sheet conveying unit, and the pair of carriage rollers are stopped and the air release control unit immediately controls the air releasing mechanism to be opened.
Dependencies are inferred from the claim text.