Denise Truscello/Getty Images If you think that companies should stick to their core expertise, Toto is here to flush away that notion. The Japanese company is best known for its bidet-style "Washlet" toilets , but it also has an advanced ceramics division that produces components used in NAND memory chips. That business gained 34 percent over last year thanks to AI chip demand, accounting for 55 percent of Toto's 53.8 billion yen ($343.5 million) operating profit so far this year. Toto expects that division to continue to grow rapidly, around 27 percent next year. To that end, the company plans to invest another 30 billion yen (around $192 million) over the next fiscal year to boost mass production and R&D. As it turns out, Toto is the world's second-largest producer of electrostatic chucks (E-chucks) used to manufacture NAND memory. Those are designed to securely hold silicon wafers into place during fabrication via electrostatic force.…