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US 8,939,558 B2Granted
Image forming apparatus including liquid ejection head
AssigneeRicoh Company, Ltd.
InventorsTomomi Katoh, Yoichi Ito, Hiroshi Noda, Jun Ichinowatari
Life of this patent
Estimating the term…
Abstract
An image forming apparatus includes a liquid ejection head, a head tank, a liquid storage container, a liquid feed device, a supply valve, an exhaust passage, a float valve, an air release valve, and a suction device. The exhaust passage is disposed in the head tank and communicated with an ambient air. The float valve is disposed in the head tank to close the exhaust passage in response to an amount of liquid in the head tank. The air release valve opens and closes the exhaust passage of the head tank. When the suction device exhausts air from the exhaust passage with the air release valve open, the liquid feed device is driven to pressurize and feed the liquid.
Claims12
An image forming apparatus comprising:
- a liquid ejection head having nozzles to eject droplets of liquid and a nozzle face in which the nozzles are formed;
- a head tank to supply the liquid to the liquid ejection head, the head tank comprising an elastic member at a top wall face of the head tank;
- a liquid storage container to store the liquid;
- a liquid feed device comprising a pressurizing pump to pressure and supply the liquid from the liquid storage container to the head tank;
- a supply valve disposed in the head tank adjacent to the elastic member to open when a negative pressure in the head tank is greater than a predetermined value;
- an exhaust passage disposed in the head tank and communicated with an ambient air;
- a float valve disposed in the head tank to close the exhaust passage in response to an amount of the liquid in the head tank;
- an air release valve to open and close the exhaust passage of the head tank;
- and
- a suction device to exhaust air from the exhaust passage,
- wherein, when the suction device exhausts air from the exhaust passage with the air release valve open, the pressurizing pump of the liquid feed device is driven to pressurize and feed the liquid,
- wherein as the liquid in the head tank is consumed the elastic member is displaced toward an interior of the head tank to drive the supply valve from a closed state to an open state, and the supply valve in the open state permits communication between the head tank and the liquid storage container,
- wherein the exhaust passage comprises a groove having an arc-shaped cross section in a short direction of the groove, and formed along the top wall face of the head tank,
- wherein the elastic member has a thin film shape to cover at least a portion of the groove, and the elastic member an outer surface portion contacting an exterior of the head tank, and an inner surface portion opposing the groove, and
- wherein when the float valve closes the exhaust passage, the elastic member deforms to compress and choke the exhaust passage.
12 more elements
An image forming apparatus comprising:
- a liquid ejection head having nozzles to eject droplets of liquid and a nozzle face in which the nozzles are formed;
- a head tank to supply the liquid to the liquid ejection head;
- a liquid storage container to store the liquid;
- a liquid feed device to feed the liquid from the liquid storage container to the head tank;
- a supply valve disposed in the head tank to open when a negative pressure in the head tank is greater than a predetermined value;
- an exhaust passage disposed in the head tank an communicated with an ambient air;
- a float valve disposed in the head tank to close the exhaust passage in response to an amount of the liquid in the head tank;
- an air release valve to open and close the exhaust passage of the head tank;
- a suction device to exhaust air from the exhaust passage;
- and
- an exhaust pressure detector to detect an exhaust pressure when the suction device is connected to the air release valve and sucks and exhausts air,
- wherein, when the suction device exhausts air from the exhaust passage with the air release valve open, the liquid feed device is driven to pressurize and feed the liquid, and
- wherein the exhaust pressure detector is disposed between the suction device and the air release valve.
10 more elements
An image forming apparatus comprising:
- a liquid ejection head having nozzles to eject droplets of liquid and a nozzle face in which the nozzles are formed;
- a head tank to supply the liquid to the liquid ejection head, the head tank comprising a film member at a wall face of the head tank;
- a liquid storage container to store the liquid;
- a liquid feed device comprising a pressurizing pump to pressurize and supply the liquid from the liquid storage container to the head tank;
- a supply valve disposed in the head tank adjacent to the film member to open when a negative pressure in the head tank is greater than a predetermined value;
- an exhaust passage disposed in the head tank and communicated with an ambient air;
- a float valve disposed in the head tank to close the exhaust passage in response to an amount of the liquid in the head tank;
- an air release valve to open and close the exhaust passage of the head tank,
- a suction device to exhaust air from the exhaust passage;
- a pressure buffer having an elastically deformable wall face to temporarily store the liquid, wherein the pressure buffer is disposed between the pressurizing pump and the head tank;
- and
- a valve unit to allow ink to he fed in only one direction, wherein the valve unit is disposed between the liquid storage container and the pressurizing pump and between the pressurizing pump and the pressure buffer,
- wherein, when the suction device exhausts air from the exhaust passage with the air release valve open the pressurizing pump of the liquid feed device is driven to pressurize and feed the liquid, and
- wherein as the liquid in the head tank is consumed the film member is displaced toward an interior of the head tank to drive the supply valve from a closed state o an open state, and the supply valve in the open state permits communication between the head tank and the liquid storage container.
11 more elements
Dependencies are inferred from the claim text.