noun
hectograph; gelatin duplicator
A printing device that uses a gelatin pad to make copies; also called jellygraph or copygraph. Domain-specific term in printing.
昔の学校では、こんにゃく版でテストを印刷していた。
In old schools, they used to print tests with a hectograph.
From こんにゃく (konjac) + 版 (printing plate), named after the gelatinous texture of the duplicator pad.