Coater design for low flowrate coating applications
AssigneeEastman Kodak Company
InventorsRichard L. Columbus, Harvey J. Palmer
Life of this patent
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Abstract
There are disclosed coaters that repeatedly and intermittently apply a uniform, thin coating of liquid onto a support at a rate that does not exceed the maximum swell rate of the support. Thus, developer liquid can be applied to photographic paper supports without leaving behind liquid effluent. The coater features a delivery channel leading from a manifold chamber to a slit orifice, the channel being improved in that it contains a plurality of spaced-apart wall portions connecting the opposed flow surfaces of the delivery channel, that extend in a direction towards the slit orifice, and structure inside the orifice for coalescing the individual streams fed by these wall portions, into a continuous strip of liquid to be dispensed by the slit orifice.
Claims7
In a photographic developer apparatus for developing a photographic product, said developer apparatus comprising a source of developer liquid and a coater for delivery of the liquid in a uniform layer onto a surface of the photographic product, said coater comprising a body having an internal manifold chamber of a width generally equal to the width of a photographic product, means for introducing the liquid at a point within said chamber, a slit orifice shaded to deliver a uniform layer of liquid, and a delivery channel having a length extending from said manifold to said orifice,
- the improvement wherein said coater delivery channel comprises spaced-apart opposed surfaces connected together for the majority of said delivery channel length at spaced intervals by a plurality of wall portions in said channel extending between said surfaces in a first direction toward said orifice to confine liquid flow into spaced-apart individual streams of flow between said wall portions, and coalescing means disposed inside said orifice next to said wall portions for coalescing said individual streams together into a substantially continuous strip of liquid while still inside said orifice, so that said developer is effluent-free,
- and wherein said wall portions extend substantially completely across the gap between said surfaces and to said orifice with a thickness that tapers sufficiently as the orifice is reached as to aid coalescence of said separate streams at said orifice.
In a photographic developer apparatus for developing a photographic product, said developer apparatus comprising a source of developer liquid and a coater for delivery of the liquid in a uniform layer onto a surface of the photographic product, said coater comprising a body having an internal manifold chamber of a width generally equal to the width of a photographic product, means for introducing the liquid at a point within said chamber, a slit orifice shaded to deliver a uniform layer of liquid, and a delivery channel having a length extending from said manifold to said orifice,
- the improvement wherein said coater delivery channel comprises spaced-apart opposed surfaces connected together for the majority of said delivery channel length at spaced intervals by a plurality of wall portions in said channel extending between said surfaces in a first direction toward said orifice of confine liquid flow into spaced-apart individual streams of flow between said wall portions, and coalescing means disposed inside said orifice next to said wall portions for coalescing said individual streams together into a substantially continuous strip of liquid while still inside said orifice, so that said developer is effluent-free,
- and wherein said wall portions extending between said surfaces have a transverse thickness that decreases as said wall portions approach said orifice so as to minimize liquid flow vortices that can be created by said wall portions.
Dependencies are inferred from the claim text.