JP2005262879A5

JP2005262879A5 -

Info

Publication number: JP2005262879A5
Application number: JP2005044188A
Authority: JP
Filing date: 2005-02-21
Publication date: 2008-03-27
Anticipated expiration: 2025-02-21

Claims

In an image forming apparatus for supplying an ink contained in an ink tank to an ink jet head and ejecting the ink from the ink jet head to form an image on an image forming medium.
A pressure unit that pressurizes the ink path from the ink tank to the inkjet head;
An air opening portion for opening the ink path to the atmosphere;
A control unit that controls at least the air release unit when performing maintenance of the inkjet head;
The control unit seals the inside of the ink path by the atmosphere opening unit, pressurizes the inside of the ink path by the pressurizing unit in this state, and increases the head internal pressure of the ink jet head. An ink discharge control unit for discharging
After the ink is ejected from the inkjet head by the ink ejection control unit, the air in the pressurized ink path is discharged from the atmosphere release unit, and the head internal pressure is reduced to a predetermined pressure. After the depressurization step and the first depressurization step, the discharge area for discharging the air in the ink path of the atmosphere opening portion is made smaller than the discharge area in the first depressurization step, and the air in the ink path is further reduced. And an air discharge controller that performs a second pressure reducing step for reducing the internal pressure of the head to a fine positive pressure.

The discharge amount of the air in the ink path discharged from the atmosphere release portion at the time of the second pressure reduction step is the amount of the air in the ink path discharged from the atmosphere release portion at the time of the first pressure reduction step. The image forming apparatus according to claim 1, wherein the image forming apparatus is less than a discharge amount.

The atmosphere release section has a plurality of atmosphere release pipes communicating with the ink tank and a plurality of atmosphere release valves provided in each atmosphere release pipe,
The air discharge control unit
In the first pressure reducing step, at least two or more atmosphere release valves among the plurality of atmosphere release valves are opened, and the air is discharged from the ink path through the atmosphere release pipe.
In the second decompression step, the number of atmosphere release valves that release the atmosphere among the plurality of atmosphere release valves is less than that in the first decompression step, and the air is discharged from the ink path through the atmosphere release pipe. The image forming apparatus according to claim 1, wherein the image forming apparatus is an image forming apparatus.

Two of the plurality of atmosphere release pipes are provided in the ink tank,
The air discharge control unit opens the two atmosphere release pipes provided in the ink tank in the first decompression step, and releases the atmosphere of one of the two atmosphere release tubes in the second step. 4. The image forming apparatus according to claim 3, wherein only the tube is opened.

The plurality of open air pipes are configured with different discharge areas,
4. The maintenance method of an ink jet head according to claim 3, wherein in the second decompression step, only the air release valve of the air release pipe having a small discharge area is opened.

The plurality of atmosphere release pipes are provided in the ink tank with two different discharge areas,
The air discharge control unit
In the first depressurization step, the two atmosphere open tubes are opened, and in the second depressurization step, only the atmosphere open tube having a small discharge area is opened among the two atmosphere open tubes. The image forming apparatus according to claim 5.

The plurality of atmosphere open pipes are configured to have different lengths,
4. The maintenance method of an ink jet head according to claim 3, wherein in the second pressure reducing step, only the air release valve of the air release pipe having a long length is opened.

The plurality of atmosphere release pipes are provided in the ink tank with two different lengths, respectively.
The air discharge control unit
In the first depressurization step, the two atmosphere release pipes are opened, and in the second step, only the long atmosphere release pipe among the two atmosphere release pipes is opened. The image forming apparatus according to claim 7.

9. The long open air pipe among the plurality of open air pipes is configured to have a discharge area smaller than that of a short open air pipe. The image forming apparatus described in 1.

The image forming apparatus according to claim 7, wherein the plurality of atmosphere release pipes are branched from one atmosphere release pipe.

The atmosphere release section has a plurality of atmosphere release pipes having different discharge areas communicating with the ink tank and atmosphere release valves provided in the respective atmosphere release pipes,
The air discharge control unit
In the first decompression step, only the air release tube having a large discharge area among the atmosphere release tubes is opened to discharge the air from the ink path, and in the second decompression step, the discharge is performed among the atmosphere release tubes. The image forming apparatus according to claim 1, wherein only the air release pipe having a small area is opened to discharge the air from the ink path.

The plurality of atmosphere release pipes are provided in the ink tank with two different discharge areas,
The air discharge control unit
In the first depressurization step, only the atmosphere release tube having a large discharge area among the two atmosphere release tubes is opened, and in the second step, the atmosphere release tube having a small discharge area among the two atmosphere release tubes. The image forming apparatus according to claim 11, wherein only the image forming apparatus is opened.

The atmosphere release section includes an atmosphere release pipe communicating with the ink tank and an atmosphere release valve provided in the atmosphere release pipe, and the atmosphere release valve makes a discharge area of the atmosphere release pipe variable. The image forming apparatus according to claim 1 or 2.

A plurality of ink tanks each containing each ink;
An inkjet head that is provided corresponding to each of the plurality of ink tanks, discharges the ink supplied from the ink tanks onto an image forming medium, and performs image recording;
One pressure tank for pressurizing the plurality of ink tanks;
A plurality of communicating members having pressurizing valves that respectively communicate between the plurality of ink tanks and the one pressurized tank;
A plurality of air release valves provided for each of the plurality of ink tanks to release the plurality of ink tanks to the atmosphere;
A control unit that controls at least opening and closing operations of the pressurization valve and the atmosphere release valve when performing maintenance of the inkjet head;
The control unit closes all of the plurality of atmospheric release valves and opens all of the pressurization valves provided on the plurality of connecting members, thereby allowing the one pressurization tank to pass through the plurality of ink tanks. Increasing the internal pressure of the inkjet head and discharging the ink from the inkjet head;
After the ink is ejected from the inkjet head by the ink ejection control unit, the atmosphere release valve is opened with all the pressure valves opened, and the pressurized air in the ink tank is discharged. A first pressure reducing step for reducing the internal pressure of the head to a predetermined pressure; and a discharge area of the air discharged by the atmosphere release valve after the first pressure reducing step is smaller than a discharge area at the time of the first pressure reducing step. And an air discharge control unit that discharges the air in the ink path and performs a second pressure reducing step of reducing the internal pressure of the head to a fine positive pressure.

The air discharge control unit discharges the air from the ink tank by reducing the number of the plurality of atmosphere release valves that are opened to the atmosphere in the second pressure reducing step as compared with the first pressure reducing step. Item 15. The image forming apparatus according to Item 14.

The image according to claim 14, wherein the air discharge control unit opens the plurality of atmosphere release valves in the first pressure reducing step and sequentially closes the plurality of atmosphere release valves in the second step. Forming equipment.

The air discharge control unit opens the plurality of atmosphere release valves in the first pressure reducing step, and opens only one atmosphere release valve among the plurality of atmosphere release valves in the second step. The image forming apparatus according to claim 14.

In a maintenance method of an inkjet head that ejects ink,
A purging step of pressurizing the ink path connected to the ink jet head and discharging the ink from the ink jet head due to a pressure increase in the ink path;
A first depressurization step for releasing the pressure in the ink path by releasing the air from the ink path by opening the ink path to the atmosphere after the purging step;
When the pressure in the ink path approaches the atmospheric pressure by the first pressure reducing step, the discharge area for discharging the air from the ink path is made smaller than that in the first pressure reducing step, and further from the ink path A second pressure reducing step of discharging air and reducing the pressure in the ink path to a slight positive pressure;
A maintenance method for an ink jet head, comprising:

A plurality of ink tanks that store each ink, an inkjet head that is provided corresponding to each of the plurality of ink tanks and that discharges the ink supplied from the ink tank, and an air that is connected to the plurality of ink tanks A maintenance method for an inkjet head in an image forming apparatus having a tank and a pressure pump for pressurizing the inside of the air tank,
Pressure supply that drives the pressure pump and raises the pressure in the air tank to a predetermined pressure
Process,
A purge step of communicating the plurality of ink tanks and the air tank when the pressure in the air tank reaches a predetermined pressure, and discharging the ink from the inkjet head via the plurality of ink tanks;
After the purge step, the air tank and the plurality of ink tanks are in communication with each other, the plurality of ink tanks are opened to the atmosphere, and air is discharged from the plurality of ink tanks to reduce the pressure in the ink tanks. A first depressurization step for depressurization;
After the first pressure reducing step, a discharge area for discharging the air from the plurality of ink tanks is made smaller than that in the first pressure reducing step, and the air is discharged from the plurality of ink tanks. A second pressure reducing step for reducing the pressure to a slight positive pressure;
A maintenance method for an ink jet head, comprising: