Final answer:
Gainax studio's OVA 'Aim for the Top! Gunbuster' in 1988 was a key moment for the U.S. exposure to anime, showcasing the increasing global influence of Japanese animation led by artists such as Akira Toriyama and Tite Kubo.
Step-by-step explanation:
The first widespread exposure that U.S. fans had to anime was in 1988 when Gainax, a fledgling anime studio in Japan, produced an Original Video Animation (OVA) known as Aim for the Top! Gunbuster. This anime was significant in the spread of Japanese animation in the United States, marking a moment in history where the anime art form began to reach a broader audience. Influence on anime was also greatly impacted by artists like Akira Toriyama, known for creating Dr. Slump and Dragon Ball, and Tite Kubo, known for the Bleach series. These creators, alongside their series, have been influential in shaping the anime industry, creating significant milestones in its globalization.