MicroTFP print chips are manufactured at Epson's Suwa Minami Plant, in Nagano prefecture in Japan. Three silicon chips - a TFP actuator, an ink channel, and a nozzle plate - are bonded together. Ink that enters through the ink flow path of the ink channel is ejected from the nozzles by pump-like action of the TFP actuator. Epson's innovative thin-film piezo technology is used to produce the TFP actuators; its innovative MEMS technology is used to make the chip components.

1. Thin Film Piezo (TFP) technology

An TFP actuator is an extremely thin piezo element formed on a silicon substrate. The piezo element contracts when a voltage is applied to it. This movement provides the power to drive ink, which flows into the ink flow path, from the nozzle plate.

Thin film piezo technology is used to form piezo elements on a silicon wafer in uniform, one-micrometer-thick films. High-quality ceramic crystals that have consistent orientation are formed by sintering using Epson's own crystallization process.

These TFP actuators provide extremely precise control over droplet size and placement and astonishingly accurate prints. That is because their uniform crystal structure means that they maintain uniform displacement when they contract and because the extreme thinness of the piezo film allows for larger contractions and, thus, larger displacement.

Epson manufactures the material for the piezo elements themselves. We also independently developed the chemical reaction process used to synthesize the materials as well as the synthesizing equipment. Having access to the best piezoelectric materials to meet the performance requirements of the piezo elements is a huge advantage for Epson.

2. MEMS technology
High-accuracy, 3D submicron photolithography is a source of Epson's MEMS process strength. In ordinary semiconductor fabrication the dimensional accuracy required for planar processing is high, but the accuracy required for thicknesses is not all that high. Industrial equipment used in the photolithography step normally has several percent variation, but Epson is able to limit this variation anywhere from one-fifth to one-tenth.

This level of accuracy exceeds conventional systems and is among the best in the industry. And it is this that enables us to form extremely fine and intricate TFP actuators, ink channels, and nozzle plates. These are what provide the picoliter-level control over ejected ink volume and the extraordinary precision of dot placement on media.

The nozzles in thermal heads produced on photosensitive resin are only about several microns in length. In contrast, nozzles in MicroTFP print chips produced on silicon wafers may be more than 10 times that length, and this greater nozzle length translates into far more accurate ink droplet placement.