Patent ID: 7596342

Claim:
A drive transmission device comprising: a drive source; a drive shaft adapted to receive a drive force from the drive source; a driven shaft connected to the drive shaft so as to transmit the drive force; a conductive housing having an electro-rheological fluid sealed therein; an applying unit configured to apply an electric field to the electro-rheological fluid; and a switching unit configured to switch an electric-field applying line by the applying unit between a first electric-field applying line and a second electric-field applying line, the first electric-field applying line having the drive shaft and the driven shaft functioning as electrodes, the second electric-field applying line having the driven shaft and the housing functioning as electrodes, wherein the drive force is transmitted from the drive source to the driven shaft when the first electric-field applying line is selected by the switching unit, and the rotation of the driven shaft is braked when the second electric-field applying line is selected.