Abstract A developing liquid feed device to be used in a wet process electrophotographic apparatus for feeding a developing liquid having a toner concentration higher than that of the developing solution in the main developing chamber, comprising a developing liquid feed storage tank having a normally closed valve therein which valve is opened by appropriate means when the tank is mounted upon the main developing chamber permitting the developing liquid therein to be metered into the main developing solution. A premix chamber is floated in the main developing solution beneath the valve in the storage tank to receive the developing liquid passing therethrough. This premix chamber is provided with means for exerting a buoyant force sufficient to overcome the head of the developing liquid and thus maintains the uppermost edge of the premix chamber above the level of the developing solution. When the developing solution is at a predetermined level, the developing liquid in the premix chamber closes off the valve so that there is no metering of the developing liquid from the storage tank, but when the solution drops below the predetermined level, the concurrent dropping of the premix chamber opens the valve, permitting developing liquid to pass through the premix chamber into the main developing chamber until the solution is again raised to the predetermined level.
A developing liquid feed device as specified in claim 1 wherein said premix developing liquid chamber has an arm whose one end is securely fixed to said intermediate chamber and whose the other end is pivotably fixed to the sidewall of said developing liquid chamber, whereby said intermediate chamber may move along a predetermined path when the liquid level in said developing liquid chamber varies.
Claim 2
Dependent Claim
57 words
A developing liquid feed device as specified in claim 1 wherein said intermediate developing liquid chamber has a rod extending downwardly from the bottom of said intermediate chamber and fitted into guide means securely fixed to the bottom of said developing liquid chamber, thereby preventing the lateral deviation of said intermediate chamber when it is moved vertically.
Claim 3
Dependent Claim
169 words
Apparatus for wet process electrophotography, comprising a. a developing chamber containing a first supply of developing liquid; b. a developing liquid feed tank containing a second supply of developing liquid and mounted on said developing chamber, said tank having a valve therein for metering said second supply of developing liquid to said developing chamber; c. a premix chamber floated in the first supply of developing liquid in said developing chamber in cooperating relation with said valve; and d. means for exerting a buoyant force on said premix chamber sufficient to maintain the uppermost edge of said premix chamber above the level of the first supply of developing liquid in said developing chamber, such that said valve is closed by said premix chamber when said first supply of developing liquid is above a predetermined level in said developing chamber and said valve opens communicating said second supply of developing liquid to said developing chamber through said premix chamber when said first supply of developing liquid drops below said predetermined level.