Three-dimensional printing device

1. A three-dimensional printing device, comprising:

a printing tank to accommodate a powder material and including an opening in at least a portion thereof; and

an ejector facing the opening of the printing tank to eject a curing liquid to cure the powder material toward the opening; wherein

the ejector includes a plurality of nozzle strings each including a plurality of nozzles side by side in a predetermined first direction to eject the curing liquid;

the plurality of nozzles are located in each of the plurality of nozzle strings at a density of about 1200 dpi or lower in the first direction;

the plurality of nozzle strings are spaced away from each other by a distance of about 5 mm or longer in a second direction perpendicular to the first direction;

the powder material includes ceramic powder and binder powder; and

the curing liquid is water including surfactant.

2. The three-dimensional printing device according to claim 1 , wherein the plurality of nozzle strings are spaced away from each other by a distance of about 11 mm or longer in the second direction.

3. A three-dimensional printing device, comprising:

a printing tank to accommodate a powder material and including an opening in at least a portion thereof;

an ejector facing the opening of the printing tank to eject a curing liquid to cure the powder material toward the opening; and

a controller to control the ejector to eject the curing liquid; wherein

the powder material includes ceramic powder and binder powder;

the curing liquid is water including surfactant;

the ejector includes:

a first nozzle string including a first plurality of nozzles side by side in a predetermined first direction to eject the curing liquid;

a second nozzle string including a second plurality of nozzles side by side in the first direction to eject the curing liquid; and

a third nozzle string including a third plurality of nozzles side by side in the first direction to eject the curing liquid;

the first nozzle string and the second nozzle string are spaced away from each other by a distance shorter than 5 mm in a second direction perpendicular to the first direction;

the first nozzle string and the third nozzle string are spaced away from each other by a distance equal to, or longer than, 5 mm in the second direction; and

the controller is configured or programmed to, in at least a portion of a time duration in which the ejector ejects the curing liquid, cause the curing liquid to be ejected from the first plurality of nozzles of the first nozzle string and the third plurality of nozzles of the third nozzle string but not to be ejected from the second plurality of nozzles of the second nozzle string.

4. The three-dimensional printing device according to claim 3 , wherein the controller is configured or programmed to:

in a portion of the time duration in which the ejector ejects the curing liquid, cause the curing liquid to be ejected from the first plurality of nozzles of the first nozzle string and the third plurality of nozzles of the third nozzle string but not to be ejected from the second plurality of nozzles of the second nozzle string; and

in another portion of the time duration in which the ejector ejects the curing liquid, cause the curing liquid to be ejected from at least the second plurality of nozzles of the second nozzle string but not to be ejected from the first plurality of nozzles of the first nozzle string.

5. The three-dimensional printing device according to claim 4 , wherein the controller is configured or programmed to include:

a first counter to count an accumulated time duration in which the curing liquid is ejected from the first plurality of nozzles of the first nozzle string and the third plurality of nozzles of the third nozzle string but not ejected from the second plurality of nozzles of the second nozzle string;

a second counter to count an accumulated time duration in which the curing liquid is ejected from at least the second plurality of nozzles of the second nozzle string but not ejected from the first plurality of nozzles of the first nozzle string; and

a nozzle string selector to stop the ejection of the curing liquid from the first plurality of nozzles of the first nozzle string and the third plurality of nozzles of the third nozzle string, and cause the curing liquid to be ejected from the second plurality of nozzles of the second nozzle string, when the accumulated time duration counted by the first counter exceeds a predetermined time duration, and to stop the ejection of the curing liquid from at least the second plurality of nozzles of the second nozzle string, and cause the curing liquid to be ejected from the first plurality of nozzles of the first nozzle string, when the accumulated time duration counted by the second counter exceeds a predetermined time duration.

6. The three-dimensional printing device according to claim 4 , wherein the controller is configured or programmed to include:

a first counter to count an accumulated number of times by which the curing liquid is ejected from the first plurality of nozzles of the first nozzle string and the third plurality of nozzles of the third nozzle string; and

a second counter to count an accumulated number of times by which the curing liquid is ejected from the second plurality of nozzles of the second nozzle string; and

a nozzle string selector to stop the ejection of the curing liquid from the first plurality of nozzles of the first nozzle string and the third plurality of nozzles of the third nozzle string, and cause the curing liquid to be ejected from the second plurality of nozzles of the second nozzle string, when the accumulated number of times counted by the first counter exceeds a predetermined number of times, and stop the ejection of the curing liquid from at least the second plurality of nozzles of the second nozzle string, and cause the curing liquid to be ejected from the first plurality of nozzles of the first nozzle string, when the accumulated number of times counted by the second counter exceeds a predetermined number of times.

7. The three-dimensional printing device according to claim 4 , wherein the controller is configured or programmed to include:

a first counter to count an accumulated number of cured layers formed by ejection of the curing liquid from the first plurality of nozzles of the first nozzle string and the third plurality of nozzles of the third nozzle string; and

a second counter to count an accumulated number of cured layers formed by ejection of the curing liquid from the second plurality of nozzles of the second nozzle string; and

a nozzle string selector to stop the ejection of the curing liquid from the first plurality of nozzles of the first nozzle string and the third plurality of nozzles of the third nozzle string, and cause the curing liquid to be ejected from the second plurality of nozzles of the second nozzle string, when the accumulated number of the cured layers counted by the first counter exceeds a predetermined number, and stop the ejection of the curing liquid from at least the second plurality of nozzles of the second nozzle string, and cause the curing liquid to be ejected from the first plurality of nozzles of the first nozzle string, when the accumulated number of the cured layers counted by the second counter exceeds a predetermined number.

8. The three-dimensional printing device according to claim 3 , wherein:

the first nozzle string and the second nozzle string are spaced away from each other by a distance shorter than 11 mm in the second direction; and

the first nozzle string and the third nozzle string are spaced away from each other by a distance equal to, or longer than, 11 mm in the second direction.