Black ink composition
AssigneeSeiko Epson Corporation
InventorsChie Maruyama, Miharu Kanaya
Life of this patent
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Abstract
Provided is a black ink composition containing a pigment, wherein the value calculated from the average particle diameter and the particle size distribution width of the pigment and the ink viscosity is regulated within a certain range, and the number of coarse particles contained in the ink composition is regulated to a certain value or less. The ink composition is excellent in ink storage stability and can give an image realized with good balance between color development, in particular, in high-speed printing and inhibition of a time-dependent change in printing density due to pigment sedimentation.
Claims12
A black ink composition comprising a pigment, wherein the value, X, calculated, from the average particle diameter (nm), D50%, of the pigment contained in the ink composition, the particle size distribution width (nm), D90%-D10%, of the pigment contained in the ink composition, and the ink viscosity (mPa·s), η, at 20° C., by the following Expression (I):
- X={D50%X(D90%-D10%)}/η (I)
- is within a range of 2500 to 4500, and the number of coarse particles having a pigment particle size not smaller than 0.5 μm contained in the ink composition is 7.0×109 or less per 1 mL of the ink composition.
Dependencies are inferred from the claim text.