My remaining print quota is not large enough to print it in color. Even if I try to change to monochrome on the on-demand terminal, an error occurs and I cannot print it.

Specify monochrome settings on the application side so that the print request is sent as a monochrome data to the on-demand terminal.

However, in applications such as Word, monochrome data may not be produced as intended, so please refer to the FAQ below for concrete methods:

Even if I send a print request in monochrome setting from Word, for some reason it becomes in color setting on the on-demand terminal.
https://www.u.tsukuba.ac.jp/ufaqs/en-printing-mono/