Apparatus for forming image on copying machine at variable zoom ratio

摘要

A three-group lens barrel for zooming in a photo-copier in which the barrel is movable and fixes a middle lens group. The front and rear lens group are slidable in the barrel. The front and rear lens groups are connected to ends of two link levers. The link levers are swung together or apart by a common pin connection to a swing lever which has at one end a cam follower following a cam groove in the photo-copier. The common pin may be eccentric to finely adjust the lens separation.