Process for forming coating on running film and apparatus therefor

A process for forming a coating having a constant thickness on at least one surface of a running film, which comprises

• continuously providing at least one surface of a running film with a first coating liquid film having a thickness greater than an intended thickness,
• transferring the first coating liquid film onto a roll which is in contact with the running film and rotates in the direction counter to the running direction of the running film,
• changing the first coating liquid film into a second coating liquid film having an intended constant thickness with a metering means on the roll, said metering means being a doctor knife spaced apart from the roll by a distance equal to the intended constant thickness, said doctor knife having a surface which contacts the coating liquid on the roll, said contact of said coating liquid and said surface generating a force on said doctor knife, said force on said doctor knife having a component normal to the surface of the roll, and then
• transferring the second coating liquid film having the constant thickness onto the running film.