US 6,886,902 B2 · Ink jet printing system and method for controlling the printing quality

Abstract

This invention relates to an ink jet system (10) and to a corresponding method of use suitable for rendering the printing characteristics homogeneous upon changes in working conditions, such as the type of printing medium, inks and ambient conditions. The object is attained through optical means (24) suitable for detecting the quantity of light reflected by appropriate patterns and a control unit (21) suitable for processing the data corresponding to the quantity of light reflected in order to identify the real dimensions of the ink droplets (dot size) on the printing medium and for transmitting them to the print management programs or print drivers (67b). The system (10) and method guarantee total independence from the working conditions, with the result that the images printed will be uniform no matter what the conditions.

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Drawings

Claims8

Dependent claims

An ink jet printing system (10) comprising:

printing equipment (12) having a ink jet printhead (22) for printing on a medium via the ejection of droplets of ink;
a print driver (21) associated with said printing equipment (12) and configured both for processing data to be printed on the basis of information indicative of the medium and of the dimensions of the droplets of ink on the medium and for supplying the processed information to the printing equipment (12);
pattern printing means for printing on said medium with said ink jet printhead (22) a plurality of patterns (30, 30a, 30b, 30c) of predefined different densities (Ks), in order to obtain corresponding optical effects;
superpixel printing means for printing on said medium with said ink jet printhead (22) an area constituted by at least one typical superpixel (31) having a predefined intensity and being calculated from typical information on the medium and on the printed dot size;
optical analysis means comprising an optical device (24) associated with said printing equipment (12), said optical analysis means being configured for:
reading by said optical device (24) such plurality of printed patterns (30, 30a, 30b, 30c),
analyzing the optical signals (VA) generated by said optical device (24) by reading said plurality of printed patterns (30, 30a, 30b, 30c),
extrapolating from the analysis of said optical signals corresponding to said printed patterns (30, 30a, 30b, 30c) a characteristic curve indicative of the optical effect of said printed patterns upon changes in the density of said printed patterns (30, 30a, 30b, 30c),
reading by said optical device (24) such printed typical superpixel (31), and
identifying a real optical density (Kt) corresponding to said printed typical superpixel (31), by interpolation of said characteristic curve with the optical signal generated by said optical device (24) by reading said printed typical superpixel (31);
computing means (14) for calculating the real dimensions (Ad) of the dot printed on the medium by said real optical density (Kt) identified by said optical analysis means;
and
means for supplying said print driver (21) with said real dimensions (Ad) of the dot printed on the medium.

10 more elements

An ink jet printing system (10) comprising:

printing equipment (12) having an ink jet printhead (22) for printing on a medium via the ejection of droplets of ink;
a print driver (21) associated with said printing equipment (12) and suitable both for processing data to be printed on the basis of information indicative of the medium and of the dimensions of the droplets of ink on the medium, and for supplying the processed information to the printing equipment (12);
pattern printing means for printing on said medium with said ink jet printhead (22) a composite pattern (35, 35a, 35b) comprising:
a pattern of predefined density (Kt);
and
a plurality of patterns obtained with values typical of the medium and of the printed dot size and representing a corresponding plurality of superpixels of intensity variable about the predefined density (Kt) of said pattern of predefined density (Kt);
optical analysis means comprising an optical device (24) associated with said printing equipment (12), said optical analysis means being configured for:
reading by said optical device (24) such printed composite pattern (35, 35a, 35b),
analyzing the optical signals (V, Vt, Vs) generated by said optical device (24) and corresponding to the different patterns of said printed composite pattern (35, 35a, 35b), and
identifying from the analysis of said optical signals (V, Vt, Vs) a determined superpixel having a determined intensity (Ks) and capable of providing an optical effect equivalent to that of said pattern of predefined density (Kt);
and
computing means (14) for computing from the results of the optical analysis performed by said optical analysis means (24) the real dimensions (Ad) of the dot printed on the medium, said computing means being suitable for calculating said real dimensions by way of said determined intensity (Ks) of said determined superpixel.

9 more elements

A method for controlling the printing quality of a printing system (10) comprising printing equipment (12) having a ink jet printhead (22) for printing on a medium via the ejection of droplets of ink and a print driver (21) associated with said printing equipment (12), said print driver (21) being configured both for processing data to be printed on the basis of information indicative of the medium and of the dimensions of the droplets of ink on the medium and for supplying the processed information to the printing equipment (12), said method comprising the following steps:

printing on said medium with said ink jet printhead (22) a plurality of patterns (30, 30a, 30b, 30c) of predefined different densities (Ks) to obtain corresponding optical effects;
optically analyzing the optical density of said plurality of printed patterns;
calculating from the results of said optical analysis the real dimensions of the dot printed on the medium;
and
supplying said print driver with said real dimensions of the dot printed on the medium,
wherein the printing step includes:
printing on said medium with said printhead (22) a typical superpixel (31) having a predefined intensity and being calculated from typical information on the medium and on the printed dot size;
wherein the step of optically analyzing is performed by using an optical device (24) associated with said printing equipment and includes:
extrapolating from the optical analysis of said plurality of printed patterns a characteristics curve indicative of the optical effect upon changes in the density of said patterns;
detecting by said optical device (24) the optical effect of the printed typical superpixel (31);
and
identifying the optical density (Kt) corresponding to said printed typical superpixel (31), by interpolation of said characteristic curve with the detected optical effect of said printed typical superpixel (31);
and
wherein the calculating step includes using the identified optical density (Kt) in order to calculate the real dimensions of the printed dot on the medium.

11 more elements

Dependencies are inferred from the claim text.

Description3,602 words

Summary1,453 words

#This invention relates to an ink jet printing system comprising printing equipment suitable for printing images of given characteristics and a print driver suitable for controlling the characteristics of the printing equipment, depending on the size of the drops of ink on the medium, and to the relative method for controlling the printing quality.

#More particularly the invention relates to a system and method for rendering the printing characteristics of printing equipment homogeneous in the presence of changing working conditions.

#Printing systems are known in the art, such as for instance printers, photocopiers, fax machines, etc., that are suitable for producing the printout of a document by means of ink jet printing devices in the form of fixed or interchangeable printheads.

Brief description of the drawings6 figures

#These and other characteristics of the invention will become clear from the following description of a preferred embodiment, provided by way of a nonrestrictive example with the aid of the accompanying diagrams, wherein:

#FIG. 1 is a block diagram of a printing system according to the invention;

#FIG. 2 is a summary diagram of the optical device of the system of FIG. 1;

Detailed description2,009 words

#With reference to FIG. 1, the printing system 10 according to this invention comprises printing equipment 12, suitable for printing texts and/or images on various types of media, and a computer 14, for example a personal computer or PC, suitable for processing, with appropriate programs, the printing data, texts or images, and transmitting this processed data to the printing equipment 12 by means of a connecting cable 15, a parallel cable for instance.

#The printing equipment 12 comprises a print controller 21, an ink jet printhead 22, of known type, an optical device 24, of known type, connected to the print controller 21 and controlled by the latter.

#The printing equipment 12 also comprises an interface device 25, of known type, for instance of the parallel type, connected to the cable 15 and to the print controller 21 and suitable for transmitting data and parameters to the computer 14, a random access memory (printer RAM) 27, of known type, suitable for storing, under the control of the print controller 21, the information processed by the computer 14 and transmitted by the latter to the printing equipment 12, and a read only memory (printer ROM) 29, of known type, suitable for storing data, for example calibration patterns, and programs developed in the design stages of the printing equipment 12.

Facts

Application

10/332,488Filed 9 Jul 2001

Priority

IT TO2000A068810 Jul 2000

Published

US 2004/0090481 A113 May 2004

Granted

3 May 2005

Term ended

12 Nov 2021

Estimated · how

20 years from earliest known nonprovisional domestic filing plus recorded patent term adjustment, including 126 days of adjustment. Maintenance-fee lapses, terminal disclaimers and statutory extensions have not been checked. The continuity chain may be incomplete; this is not an enforceability determination.

Classification3 codes

B41J 2/2121
For multi-colour printing: characterised by dot size, e.g. combinations of printed dots of different diameter
B41J 2/2135
Print quality control characterised by dot disposition, e.g. for reducing white stripes or banding: alignment of dots
B41J
Typewriters

Timeline

10 Jul 2000Priority claimedIT TO2000A0688
9 Jul 2001Application filedUS 10/332,488
9 Jan 2003Assigned to Olivetti Tecnost S.P.A.assignment of assignor's interest
13 May 2004PublishedUS 2004/0090481 A1
3 May 2005GrantedUS 6,886,902 B2
10 Jan 2014Assigned to Sicpa Holding SAassignment of assignor's interest
12 Nov 2021Term endedEstimated, includes 126 days of adjustment

Ink jet printing system and method for controlling the printing quality

Life of this patent

Ink jet printing system and method for controlling the printing quality

Life of this patent

Life of this patent

Abstract

Drawings

Drawings

Claims8

Description3,602 words

Classification3 codes

Life of this patent

Drawings

Description3,602 words