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1. Field of the Invention
The present invention relates to the field of toners or inks used in imaging
processes, particularly electro photographic or electrographic imaging
processes. The invention also relates to compositions, apparatus and methods
for reducing solvent or carrier emission in imaging systems.
2. Background of the Art
Electro photography is generally classified into wet and dry methods. In the
former, a permanent image may be obtained through the steps of forming an
electrostatic latent image on an image-bearing element such as a selenium
electrophotographicelement, a zinc oxide electro photographic element or the
like, developing the thus formed image with a liquid developer, transferring
the developed image onto a transfer sheet as occasion demands, and thereafter
heating and drying the developed or transferred image by means of a heating
means such as heat roller or the like further as occasion demands. In the
latter, on the other hand, a permanent image may be obtained through the
steps of developing an electrostatic latent image formed in the same manner
as described above with a powder developer (toner particles), transferring
said image onto a transfer sheet as occasion demands, and thereafter
thermally fixing the image by means of a heating means such as heat roller or
the like. In addition, a method is also known which is designed to form an
electrostatic latent image on an electrostatic recording element (which is
also called a dielectric element) in place of an electro photographic element.
In this connection, it is to be noted that the electro photographic element
and electrostatic recording element shall hereinafter be called "an
element being developed" respectively.
3. In the case of the wet method, an odorous solvent
vapor-containing exhaust gas is discharged from a wet type electro
photographic machine utilizing this method, because the liquid developer used
in the developing step contains a large quantity of solvent consisting
essentially of a, such as a paraffin or isoparaffinic hydrocarbon. This
solvent vapor is caused by evaporation of the solvent attached to the element
being developed in the developing step or to the transfer member in the
transferring step, but additionally by evaporation of the solvent attached to
the developing unit or the like. This generation of solvent vapor is further
accelerated when the element being developed or transfer member is heated and
dried in drying step and/or is fused to permanently fix the image to a final
receptor by means of a heating means. Even in "dry" toner systems,
there is residual solvent (also usually non-polar hydrocarbon solvent)
present in the toner that is released by development procedures.
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