Roll coating device for forming a thin film of uniform thickness

A coating device comprising:

• a transporter for transporting discrete substrates piece by piece along a predetermined direction extending along a predetermined straight transportation path parallel to a surface to be coated of each substrate, said transporter including a bed member for holding one of said substrates to be transported, said bed member and said substrate held thereon being movable together in said predetermined direction along said predetermined transportation path;
• a coating roll having an elastic outer circumferential face supplied with a coating liquid, for coating the coating liquid onto said surface of said substrate by contact at a contact position of said elastic outer circumferential face with said surface of said substrate, said coating roll being rotatable so that its elastic outer circumferential face moves in a direction opposite to the predetermined direction of the substrate at the contact position;
• a coating liquid transfer roll made of metal and having an outer circumferential face on which said coating liquid is applied, for transferring said coating liquid to said elastic outer circumferential face of the coating roll by contact of said outer circumferential face of said coating liquid transfer roll with said elastic outer circumferential face of the coating roll at a transfer position, said coating liquid transfer roll being rotatable so that said outer circumferential face thereof is rotatable in a direction opposite to said elastic outer circumferential face of said coating roll at said transfer position, said coating liquid transfer roll having a rotation axis and transfers said coating liquid to said elastic outer circumferential face of said coating roll while rotating around said rotation axis and while said outer circumferential face of said coating liquid transfer roll contacts said elastic outer circumferential face of the coating roll;
• a first support structure for rotatable supporting said coating liquid transfer roll for rotation around said rotation axis and for moving said coating liquid transfer roll between a first position wherein it is pressed against said coating roll with a predetermined pressure and a second position wherein it is spaced from said coating roll;
• a coating liquid supplier for supplying a predetermined amount of coating liquid on said outer circumferential face of said coating liquid transfer roll;
• a scraper for scraping off excess coating liquid adhering to said outer circumferential face of said coating liquid transfer roll at a location downstream of said transfer position with respect to the direction of rotation of said coating liquid transfer roll;
• and
• a receiver provided beneath said scraper for receiving said coating liquid scraped from said outer circumferential face of said coating liquid transfer roll by said scraper;
• said first support structure comprising:
• a first holding frame for holding said coating roll;
• a second holding frame supported rotatably around a predetermined position in said first holding frame for holding said coating liquid transfer roll rotatably around said rotation axis thereof;
• and
• said second holding frame and said coating liquid transfer roll being biased downwards by the weight of said second holding frame and said coating liquid transfer roll to press said coating liquid transfer roll against said coating roll.