Aprion Digital Ltd.

Hewlett-packard Industrial Printing Ltd.

Boaz Nitzan

Moshe Frenkel

Guy Peled

Naama Schur

A pretreatment liquid for applying to the upper surface of a recording media, prior to printing of printing applications using water-based ink, is provided. The liquid comprises a polyvalent metallic salt and at least one of a polymer swelling and a coalescence reagent.

Pretreatment liquid for water-based ink printing applications

A method of making a printing plate in which the uncoated surface of a substrate is treated with a pre-treatment solution prior to the deposition of ink on the surface. The pre-treatment liquid comprises a polyvalent metal salt, and at least one of an organic swelling reagent and/or a coalescence reagent. The pre-treatment liquid is applied to form a thin, homogenous layer of approximately 4 &#x3bc;m to the entire upper surface of the recording plate. The swelling reagent and/or the coalescence reagent and the polyvalent metal cations are physically well localized in the porous structure of the plate's surface. After partial drying of the pretreated anodized aluminum plate, CTP liquid is deposited onto the surface to form an image. The CTP liquid solids react with the pre-treatment liquid and are, therefore, chemically bound to the surface. This allows all data to be deposited in a single pass of the inkjet head without the problem of clustering.

Pre-treatment liquid for use in preparation of an offset printing plate using direct inkjet CTP

The surface treatment for printing applications using water-based ink of the present invention comprises a surface pretreatment of the recording media prior to the deposition of the ink on the surface, wherein the pretreatment liquid is an aqueous and/or alcoholic solution or emulsion containing a polyvalent metal salt, and at least one of an organic swelling reagent and a coalescence reagent. The pretreatment liquid is applied with a rubbing motion in a thin layer of approximately 4 &mgr;m to the entire upper surface of the recording media. The swelling reagent and/or the coalescence reagent cause the upper 3-5 &mgr;m to swell and the polyvalent metal cations become embedded in the surface. After partial drying of the pretreated media, ink composition is deposited onto the surface to form an image. The ink solids precipitate in response to the embedded cations deposited in the pretreatment, and form interactions above and below the surface of the media to give a mechanically stable ink dot. After drying at temperatures high enough to evaporate the swelling reagent and/or the coalescence reagent, the ink dot remains embedded in the surface of the media.

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Ganey-Tikva, Israel

Boaz Nitzan