Large format electrophotographic 3D printer

1. A method for constructing a three-dimensional part and a support structure with an electrophotography-based additive manufacturing system, the method comprising:

a) providing a removable support material compositionally including support material particles;

b) providing a part material compositionally including part material particles;

c) developing a support layer of the support structure from the support material with a first electrophotography engine;

d) transferring the developed support layer from the first electrophotography engine to a transfer medium;

e) developing a part layer of the three-dimensional part from the part material with a second electrophotography engine;

f) transferring the developed part layer from the second electrophotography engine to the transfer medium, wherein the developed-part and support layers have a maximum printing width in a cross-track direction and a maximum printing length in an in-track direction corresponding to a maximum printable area for the first and second electrophotography engines, respectively;

g) moving the transfer medium with the transferred part layer and the transferred support layer into alignment with a first tile region of a layer transfusion assembly;

h) transfusing the transferred part layer and the transferred support layer to previously-printed layers in the first tile region of the layer transfusion assembly;

i) repeating steps c)-f) to form a second transferred part layer and a second transferred support layer on the transfer medium;

j) moving the transfer medium with the second transferred part layer and the second transferred support layer into alignment with a second tile region of the layer transfusion assembly, wherein the second tile region is laterally adjacent to the first tile region; and

k) transfusing the second transferred part layer and the second transferred support layer to previously-printed layers in the second tile region of the layer transfusion assembly; and

wherein the three-dimensional part is constructed in a three-dimensional part region including the first and second tile regions, the three-dimensional part region being larger than the maximum printable area for the first and second electrophotography engines, a portion of the three-dimensional part being constructed in the first tile region and a portion of the three-dimensional part being constructed in the second tile region such that the three-dimensional part has a footprint that is larger than the maximum printable area for the first and second electrophotography engines.

2. The method of claim 1 , wherein step j) includes translating the layer transfusion assembly in the cross-track direction such that the three-dimensional part region has a larger width in the cross-track direction than the maximum printable area for the first and second electrophotography engines.

3. The method of claim 1 , wherein step j) includes translating the layer transfusion assembly in the in-track direction such that the three-dimensional part region has a larger length in the in-track direction than the maximum printable area for the first and second electrophotography engines.

4. The method of claim 1 , wherein the developed part layer and the developed support layer are transferred to the transfer medium in registration with each other, and wherein the transferred part and support layers are simultaneously transfused onto the previously-printed layers.

5. The method of claim 1 , wherein the layer transfusion assembly includes a build platform having a build surface onto which the three-dimensional part and the support structure are constructed, and wherein the build surface is subdivided into a plurality of tile regions, including at least the first and the second tile regions.

6. The method of claim 1 , wherein the transfer medium is a transfer belt that travels around a belt path to transport the transferred part and support layers to the layer transfusion assembly.

7. The method of claim 6 , wherein the transferred part and support layers are transfused to the previously-printed layers at a nip formed where the transfer belt passes between a nip roller and a build platform onto which the previously-printed layers were constructed.

8. The method of claim 7 , wherein the layer transfusion assembly further includes a gantry adapted to move the build platform past the nip roller in synchronization with the motion of the transfer belt such that the build platform moves at a velocity which is substantially the same as a tangential velocity of the transfer belt at the nip.

9. The method of claim 1 , wherein the layer transfusion assembly includes one or more heaters to heat the transferred heat and support layers on the transfer medium to a predefined transfusion interface temperature.

10. The method of claim 1 , wherein the layer transfusion assembly includes one or more heaters to heat a top surface of the previously-printed layers to a predefined transfusion interface temperature.

11. The method of claim 1 , wherein the layer transfusion assembly includes one or more heaters to heat the transfused heat and support layers to a predefined fusion temperature thereby fusing the transfused heat and support layers to the previously-printed layers.

12. The method of claim 1 , wherein the part material and the support material have substantially similar thermal properties and melt rheologies.

13. The method of claim 1 , further including removing the support structure from the three-dimensional part.

14. The method of claim 13 , wherein the support material is soluble in an aqueous-based solution, and wherein the support structure is removed by at least partially dissolving the support material of the support structure in the aqueous-based solution.