Macintosh
Overview
Uninstall the PS Plug-in Driver on a Macintosh.
Procedure
1
Open the [Printers & Scanners] screen.
The [Printers & Scanners] screen is opened by clicking the Apple mark and selecting [System Preferences] from [Apple Menu].
2
Select the name of the printer you want to delete and click [-].
The selected printer is deleted.
3
Close the [Printers & Scanners] screen.
4
Drag the below installed files from [Library] - [Printers] - [PPDs] - [Contents] - [Resources] in [Macintosh HD] and drop them in [Trash].
KOI140C-1J.ppd
KOI140C-1_.ppd
5
Delete any unnecessary files from [Library] - [Printers].
Drag the below files from [Library] - [Printers] - [GENERIC] and drop them in [Trash].
pstoKOI140C-1
KOI140C-1.plugin
KOI140C-1.icns
6
Click Move from the Finder menu. Hold down the option key and click [Library]. Drag the below files from [Preferences] and drop them in [Trash].
140C-1 Printer Driver Preferences
The file above may not be displayed depending on the driver setting.
[User Name] is set to the account selected when login.
7
Restart your PC.
in the upper-right of a page, it turns into 
and is registered as a bookmark.