The present disclosure is drawn to non-aqueous ink compositions. The non-aqueous ink compositions can include from 70 wt % to 98 wt % alcohol solvent, from 1 wt % to 6 wt % phenol-formaldehyde resin, from 1 wt % to 5 wt % tackifier, and from 1 wt % to 14 wt % organic solvent-soluble dye. The tackifier can include a shellac having an acid number from 50 KOH/g to 100 mg KOH/g or a tackifier resin having an acid number from 100 mg KOH/g to 300 mg KOH/g.

Examples provide inkjet ink sets and related methods. An ink set may include a pre-treatment fixing fluid, an ink, and a post-treatment fluid including a wax and a binder present in the post-treatment fluid in a range of about 10 weight percent to about 30 weight percent.

A nonaqueous inkjet printing method that can provide prints with both high printing density and good gradation is provided. The nonaqueous inkjet printing method comprises printing an image by an inkjet recording system using a first nonaqueous ink comprising at least a coloring pigment, a water-soluble resin having an amino group, and a nonaqueous solvent, and then printing an image so as to overlap with the preceding image by an inkjet recording system using a second nonaqueous ink, wherein the second nonaqueous ink comprises at least a coloring pigment, inorganic particles, and a nonaqueous solvent, and the content of the coloring pigment in the second nonaqueous ink is lower than the content of the coloring pigment in the first nonaqueous ink. The first nonaqueous ink is preferably printed at a higher resolution of printing than the second nonaqueous ink.

An ink jet recording method includes discharging a ultraviolet curable ink of which viscosity is 7 mPa.Math.s or more at 20° C. from a head toward a recording medium, and curing the ultraviolet curable ink adhered to the recording medium, wherein, in the discharging, the temperature of the ultraviolet curable ink discharged is 20 to 30° C., and the viscosity of the ultraviolet curable ink at the temperature is 13 mPa.Math.s or less.

An inkjet printing method includes the steps of: a) printing a first print job by jetting a free radical UV curable white inkjet ink from a white ink print head and one or more free radical UV curable color inkjet inks from one or more other print heads in a UV curable inkjet printer; b) filling the white ink print head in the UV curable inkjet printer with a safeguard liquid including one or more free radical polymerizable monomers; c) printing a second print job employing only the one or more other print heads in the UV curable inkjet printer for jetting one or more free radical UV curable color inkjet inks; d) replacing the safeguard liquid of the white ink print head in the UV curable inkjet printer by UV curable white inkjet ink; and e) printing a third print job by jetting free radical UV curable white inkjet ink from the white ink print head and jetting one or more free radical UV curable color inkjet inks from one or more other print heads in the UV curable inkjet printer.

In a printing method in which a base layer is formed with glossy ink or the like, a longer time period for drying the base layer is ensured. A metallic ink nozzle section, a superimposed colored ink nozzle section configured to discharge superimposed colored ink that is to be superimposed onto a metallic ink layer, and a non-superimposed colored ink nozzle section configured to discharge colored ink onto a position at which no metallic ink layer has been formed are provided. The non-superimposed colored ink nozzle section is interposed between the metallic ink nozzle section and the superimposed colored ink nozzle section.

A printing apparatus includes a first nozzle which ejects first ink containing a black coloring material, a second nozzle which ejects second ink with a low content rate of the coloring material compared to the first ink, and a control unit which controls ejecting of the ink from the first and second nozzles, in which, in a case of printing a darkest point, the control unit causes the second ink to be ejected after causing the first ink to be ejected, and causes the second ink to be ejected from the second nozzle so that a use rate of the second ink becomes 1% or more and 15% or less, when causing the second ink to be ejected.

The present invention provides a photocurable ink composition for ink jet recording with excellent curability. The photocurable ink composition for ink jet recording includes polymerizable compounds, a photopolymerization initiator, and a colorant, wherein the polymerizable compounds include a vinyl ether group-containing (meth)acrylate represented by general formula (I):
CH.sub.2═CR.sup.1—COOR.sup.2—O—CH═CH—R.sup.3  (I)
(wherein R.sup.1 is a hydrogen atom or a methyl group, R.sup.2 is a divalent organic residue having 2 to 20 carbon atoms, and R.sup.3 is a hydrogen atom or a monovalent organic residue having 1 to 11 carbon atoms) and phenoxyethyl (meth)acrylate.

To provide an image forming set including: an aqueous ink including a colorant, a water-soluble organic solvent, and water; and a post-treatment liquid including a water-soluble organic solvent, water, and at least one of a urethane resin and an acrylic resin, wherein a solubility parameter of a mixed solution of the water-soluble organic solvent and the water in the post-treatment liquid is lower than a solubility parameter of a mixed solution of the water-soluble organic solvent and the water in the aqueous ink by 1.5 (cal/cm.sup.3).sup.1/2 or greater.

An application of clear protectant to a printable medium is described that allows for different amounts of protectant to be applied to the medium based on the amounts of colorant that is applied to the medium. Colorant bitmaps are analyzed to calculate an amount of colorant coverage for a medium. Printable features in the colorant bitmaps are replicated into different intermediate protectant bitmaps based on the colorant coverage for the printable features, where the intermediate protectant bitmaps specify different amounts of protectant to apply. Features in the intermediate bitmaps are expanded and replicated into a final protectant bitmap. A determination is made for the amount of protectant to apply to the medium that is based on the different amounts specified by the intermediate bitmaps.