Mitsumi KPR Type
|This article requires photographic illustration|
|Family||Mitsumi hybrid switch|
|Switch type||Progressive rate|
|Rated lifetime||10 M|
|Bounce time||5 ms|
|Actuation force||ca. 45 g|
|Peak force||85±30 g|
|Total travel||4.0±0.5 mm|
|Keycap mount||Mitsumi mount|
Mitsumi KPR Type is a "linear" (in reality progressive rate) Mitsumi hybrid switch type; the tactile equivalent is Mitsumi KPQ Type. KPR Type also covers stock keyboards and full custom OEM products made with these switches.
KPR Type keyboards use a conductive rubber foot to bridge traces on a single membrane sheet. A coil spring is placed under the keycap to return the switch. The equivalent PCB-backed switch is Mitsumi KKR Type.
The specification below specifically notes the 4 mm travel; no KPR 3 mm specification has been found, but the Custom-Made Keyboard Profile specifications indicate that 3 mm KPR Type was available.
The switch is classified as linear, although the force curve shows it to be progressive rate.
The example below matches the KPR specification but has no Mitsumi model number. Model KPR-A77YC was found on a hand-made prototype Commodore 65 keyboard sold on eBay, made in December 1989; no pictures of this keyboard are known, but a photo of the membrane sheet exists of another C65 keyboard.
- OASYS 30LX keyboard (1990)