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US 6,644,187 B2Granted
Printer and sheet conveying device therefor
AssigneeTohoku Ricoh Co., Ltd.
InventorsToyoo Okamoto, Yoshihiko Kudoh, Akira Saito
Life of this patent
Estimating the term…
Abstract
A printer of the present invention includes a chain-delivery type of sheet conveying device arranged in an image transfer region that adjoins image transfer drums. The sheet conveying device includes a pair of drive pulleys, a pair of driven pulleys, a pair of chains each being passed over one drive pulley and one driven pulley, and a clamper affixed to the chains at opposite ends thereof. Each chain has a circumferential length that is an integral multiple of the circumference of an image transfer drum, and a number of teeth that is an integral multiple of the number of teeth of the drive pulley. A stabilizing mechanism is positioned in the image transfer region for preventing the chains from shaking.
Claims87
A printer comprising:
- at least one image carrier;
- and
- a sheet conveying device for conveying a sheet to which an image is to be transferred from said image carrier;
- said sheet conveying device comprising:
- a chain driven to run through an image transfer region, which is positioned immediately adjacent said image carrier, from an upstream side to a downstream side in a direction of sheet conveyance;
- and
- a clamper affixed to said chain for clamping the sheet fed at a sheet feed position, which is located at an upstream side of said image transfer region,
- wherein said chain is passed over a pair of toothed pulleys and has a circumferential pitch length that is an integral multiple of a circumferential length of said image carrier, and a number of teeth that is an integral multiple of a number of teeth of one of said pair of pulleys.
5 more elements
A printer comprising:
- at least one image carrier;
- and
- a sheet conveying device for conveying a sheet to which an image is to be transferred from said image carrier;
- said sheet conveying device comprising:
- a chain driven to run through an image transfer region, which is positioned immediately adjacent said image carrier, from an upstream side to a downstream side in a direction of sheet conveyance;
- a clamper affixed to said chain for clamping the sheet fed at a sheet feed position, which is located at an upstream side of said image transfer region;
- and
- a stabilizing mechanism positioned in said image transfer region for maintaining a position of said chain relative to said image carrier,
- wherein said stabilizing mechanism comprises:
- an idler pulley for maintaining the position of said chain relative to said image carrier;
- and
- a pressing roller facing said idler pulley for nipping said chain between said pressing roller and said idler pulley.
9 more elements
A printer comprising:
- at least one image carrier;
- and
- a sheet conveying device for conveying a sheet to which an image is to be transferred from said image carrier;
- said sheet conveying device comprising:
- a chain driven to run through an image transfer region, which is positioned immediately adjacent said image carrier, from an upstream side to a downstream side in a direction of sheet conveyance;
- and
- a clamper affixed to said chain for clamping the sheet fed at a sheet feed position, which is located at an upstream side of said image transfer region;
- wherein said clamper is affixed to said chain such that said clamper, clamping the sheet, conveys said sheet in a direction substantially tangential to said image carrier, and
- wherein said clamper is configured to ease collision of said clamper against rollers arranged on a conveyance path of said chain and to cause said rollers to retract.
6 more elements
The printer as claimed in claim 17, wherein said clamper includes at least two contact portions spaced from said guide member in the direction of sheet conveyance.
A printer comprising:
- at least one image carrier;
- and
- a sheet conveying device for conveying a sheet to which an image is to be transferred form said image carrier;
- said sheet conveying device comprising:
- a chain driven to run through an image transfer region, which is positioned immediately adjacent said image carrier, from an upstream side to a downstream side in a direction of sheet conveyance;
- and
- a clamper affixed to said chain for clamping the sheet fed at a sheet feed position, which is located at an upstream side of said image transfer region;
- wherein said clamper is affixed to said chain such that said clamper, clamping the sheet, conveys said sheet in a direction substantially tangential to said image carrier,
- wherein said clamper is constantly biased to remain closed, said printer further comprising cam means for sheet feed for causing, on contacting said clamper, said clamper to open and then close at the sheet feed position,
- wherein said cam means for sheet feed comprises:
- a cam for causing said clamper to open and then close;
- and
- a guide member for preventing said chain from shaking when said clamper opens and closes,
- wherein said clamper includes at least two contact portions spaced from said guide member in the direction of sheet conveyance, and
- wherein said guide member has such a length that said two contact portions contact said guide member before said clamper opens, and continuously contact said guide member until said clamper closes.
12 more elements
A printer comprising:
- at least one image carrier;
- a sheet conveying device for conveying a sheet to which an image is to be transferred from said image carrier;
- said sheet conveying device comprising:
- a chain driven to run through an image transfer region, which is positioned immediately adjacent said image carrier, from an upstream side to a downstream side in a direction of sheet conveyance;
- and
- a clamper affixed to said chain for clamping the sheet fed at a sheet feed position, which is located at an upstream side of said image transfer region;
- and
- cam means for sheet discharge for causing said clamper to open and then close on contacting said clamper at a preselected position
- wherein said clamper is affixed to said chain such that said clamper, clamping the sheet, conveys said sheet in a direction substantially tangential to said image carrier, and
- wherein said cam means for sheet discharge comprises a forcing mechanism for forcing the sheet outward of said chain in accordance with an opening motion of said clamper.
7 more elements
A sheet conveying device comprising:
- a chain driven to turn;
- a clamper affixed to said chain and biased to maintain a closed position for clamping a sheet;
- and
- cam means for sheet feed for causing said clamper to open, clamp the sheet, and then close;
- wherein said cam means for sheet feed comprises:
- a cam for causing said clamper to open and then close;
- and
- a guide member for preventing said chain from shaking when said clamper opens and closes,
- wherein said clamper includes at least two contact portions spaced from said guide member in a direction of sheet conveyance, and
- wherein said guide member has such a length that said two contact portions contact said guide member before said clamper opens, and continuously contact said guide member until said clamper closes.
7 more elements
A sheet conveying device comprising:
- a chain driven to turn;
- a clamper affixed to said chain and constantly biased to maintain a closed position for clamping a sheet;
- and
- cam means for sheet feed for causing said clamper to open, clamp the sheet, and then close;
- wherein said cam means for sheet feed comprises:
- a cam for causing said clamper to open and then close;
- and
- a guide member for preventing said chain from shaking where said clamper opens and closes,
- wherein said cam and said guide member are formed integrally with each other.
6 more elements
A sheet conveying device comprising:
- a chain driven to turn;
- a clamper affixed to said chain and biased to maintain a closed position for clamping a sheet;
- cam means for sheet feed for causing said clamper to open, clamp the sheet, and then close;
- wherein said cam means for sheet feed comprises:
- a cam for causing said clamper to open and then close;
- and
- a guide member for preventing said chain from shaking when said clamper opens and closes;
- and
- cam means for sheet discharge for causing said clamper to open and then close on contacting said clamper at a preselected position,
- wherein said cam means for sheet discharge comprises a forcing mechanism for forcing the sheet outward of said chain in accordance with an opening motion of said clamper.
7 more elements
A printer comprising:
- at least one image carrier;
- and
- a sheet conveying device for conveying a sheet to which an image is to be transferred from said image carrier;
- said sheet conveying device comprising:
- a chain driven to run through an image transfer region, which is positioned immediately adjacent said image carrier, from an upstream side to a downstream side in a direction of sheet conveyance;
- a clamper affixed to said chain for clamping the sheet fed at a sheet feed position, which is located at an upstream side of said image transfer region;
- and
- an image transfer roller for pressing the sheet against said image carrier;
- wherein said image transfer roller is smaller in diameter than said image carrier.
6 more elements
A printer comprising:
- at least one image carrier;
- and
- a sheet conveying device for conveying a sheet to which an image is to be transferred from said image carrier;
- said sheet conveying device comprising:
- a chain driven to run through an image transfer region, which is positioned immediately adjacent said image carrier, from an upstream side to a downstream side in a direction of sheet conveyance;
- a clamper affixed to said chain for clamping the sheet fed at a sheet feed position, which is located at an upstream side of said image transfer region;
- and
- a pressing roller positioned downstream, in the direction of sheet conveyance, of a position at which an image formed on said image carrier is to be transferred, for helping the sheet to be separated from said image carrier after image transfer.
5 more elements
A printer comprising:
- at least one image carrier;
- a sheet conveying device for conveying a sheet to which an image is to be transferred from said image carrier;
- said sheet conveying device comprising:
- a chain driven to run through an image transfer region, which is positioned immediately adjacent said image carrier, from an upstream side to a downstream side in a direction of sheet conveyance;
- and
- a clamper affixed to said chain for clamping the sheet fed at a sheet feed position, which is located at an upstream side of said image transfer region;
- ink feeding means for feeding ink to said image carrier;
- an intermediate image transfer body facing said image carrier and to which an image is transferred from said image carrier, wherein said intermediate image transfer body constitutes an image forming unit together with said image carrier and said ink feeding means with said sheet conveying device adjoining one side of said image forming unit;
- pressing means facing said intermediate image transfer body;
- first moving means for selectively bringing said image carrier and said ink feeding means into or out of contact with each other;
- and
- second moving means for selectively bringing said image carrier and said intermediate image transfer body into or out of contact with each other.
9 more elements
A printer comprising:
- at least one image carrier;
- a sheet conveying device for conveying a sheet to which an image is to be transferred from said image carrier;
- said sheet conveying device comprising:
- a chain driven to run through an image transfer region, which is positioned immediately adjacent said image carrier, from an up stream side to a downstream side in a direction of sheet conveyance;
- and
- a clamper affixed to said chain for clamping the sheet fed at a sheet feed position, which is located at an upstream side of said image transfer region;
- ink feeding means for feeding ink to said image carrier, wherein said ink feeding means constitutes an image forming unit together with said image carrier with said sheet conveying device adjoining one side of said image forming unit;
- pressing means facing said image carrier;
- first moving means for selectively bringing said image carrier and said ink feeding means into or out of contact with each other;
- and
- second moving means for selectively bringing said image carrier and said pressing means into or out of contact with each other.
8 more elements
A printer comprising:
- at least one image carner;
- a sheet conveying device for conveying a sheet to which an image is to be transferred from said image carrier;
- said sheet conveying device comprising:
- a chain driven to run through an image transfer region, which is positioned immediately adjacent said image carrier, from an upstream side to a downstream side in a direction of sheet conveyance;
- and
- a clamper affixed to said chain for clamping the sheet fed at a sheet feed position, which is located at an upstream side of said image transfer region;
- an intermediate image transfer body facing said image carrier and to which an image is transferred from said image carrier, wherein said intermediate image transfer body constitutes an image forming unit together with said image carrier;
- and
- pressing means facing said intermediate image transfer body;
- wherein said image forming unit comprises a plurality of ink feeding means each for feeding ink of a articular color to said image carrier.
7 more elements
A printer comprising:
- at least one image carrier;
- a sheet conveying device for conveying a sheet to which an image is to be transferred from said image carrier;
- said sheet conveying device comprising:
- a chain driven to run through an image transfer region, which is positioned immediately adjacent said image carrier, from an upstream side to a downstream side in a direction of sheet conveyance;
- and
- a clamper affixed to said chain for clamping the sheet fed at a sheet feed position, which is located at an upstream side of said image transfer region;
- pressing means facing said image carrier;
- wherein an image forming unit including said image carrier comprise a plurality of ink feeding means each for feeding ink of a particular color to said image carrier.
5 more elements
Dependencies are inferred from the claim text.