An inkjet printers linearization using 3D

gradation curves

Oleg MILDER, PhD, IRIT UrFU, Ekaterinburg Dmitry TARASOV, IRIT UrFU , Ekaterinburg

Marina Titova, IRIT UrFU , Ekaterinburgmilder@mail.ru

Color is how the reflectivity of an object is realized, taking into account its illumination and observing.

Color is a three-dimensional vector value.

Synthesis of a color is the process of obtaining a given color from the set of available ones.

Color

)(

)()()(

zyx

)(

dykY

аналогичноZY

dxkX

)()(100

,

)()()(

0

k

Lab space is a non-linear, "equally contrast" color coordinate space

Lab-coordinated

3

0

3

0

3

0

3

0

3

0

200

500

16116

ZZ

YYb

YY

XXa

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«Classical» gradation curves

fillsolidoffieldthe

ofdensityopticalDfieldscreen

ofdensityopticalD

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рп

рп

D

D

отт

рп

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%100101101

100

Linearization is a special configuration of the printer, which is responsible for supplying the ink in the required quantity.

Aim of the work: demonstration of the possibilities of gradation trajectories applied to the problems of linearization of inkjet digital printing systems.

Objectives: 1. To determine the criterion for limiting the ink supply in inkjet printing, based on the interaction of the ink and the substrate.

2. To determine experimentally the numerical value of the maximum ink feed

3. To present a linearization algorithm using gradation trajectories

Aims and objectives

Gradation Trajectory We will refer to the locus of

points in the Lab space, whose coordinates correspond to the measurement results of the individual gradation scale fields located in the order of the percentage of filling the raster cell in the layout from 0% (unprinted substrate) to 100% (die).

23

44

33

2210

44

33

2210

44

33

2210

)()()(),(),()(

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)()()(

trajectoryGradation ),,()(

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tLtLtLtLLtL

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Gradation trajectory, curvature and torsion

The experimentPrinter: Mimaki CJV30-160BSPrint mode: 720×720 variable dotPaper: MediaPrintGloss 150 г/м2.Chart generation: ChartGenerator MeasureTool ProfileMakerMeasurement: i1 iSisMathematical processing: MS Excel, MatLab

Saturation and color diagram (ab) for Cyan

22 baC

saturation

a

b

t

6

Gradation trajectory for Magenta, its Curvature and Torsion

Comparison of experimental data

Criterion for limiting

the ink supply

C M Y

0,95Сmax 60% 74% 78%Maximum curvature 75,5% 95% 91%Difference

E76 7,3 4,8 3,9

The result of linearization

Fill in the layout

Visu

al g

right

ness

, L

Algorithm of linearization using gradation trajectories

Printing and tone scale measurement

The construction of a gradation trajectory and finding the maximum of

curvature

Linearization by the selected parameter

ConclisionsGradational trajectories can be used as a replacement for traditional gradation curves when colorizing inkjet printing systems

Gradation trajectories make it possible to calculate the optimum maximum ink supply percentage by a certain criterion (maximum curvature, for example)

Gradational trajectories are invariant for a given "substrate-ink" pair

The process of linearization using gradation trajectories reduces to the displacement of points corresponding to the Lab coordinates of the target raster fields along the trajectory. The nature of the displacement depends on the parameter by which the linearization is carried out

Thanks for the attention!

An inkjet printers linearization using 3D gradation curves

Oleg MILDERDmitry TARASOV

milder@mail.ru