# US 9,038,444 B2 · Ink jet printing apparatus and method for estimating moisture content of print sheet

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- Number: US 9,038,444 B2
- Document ID: US9038444B2
- Status: Granted
- Kind: B2
- Application number: 14/287,754
- Filed: 2014-05-27
- Published: 2014-12-04
- Granted: 2015-05-26
- Earliest claimed: 2013-06-04
- Assignees: Canon Kabushiki Kaisha
- Applicants: Canon Kabushiki Kaisha
- Inventors: Riichi Saito; Noboru Toyama; Takaharu Aotani
- Web page: https://patentgrep.com/patent/US9038444B2

## CPC

- B41J 11/0022: {using convection means, e.g. by using a fan for blowing or sucking air}
- B41J 11/0005: {Curl smoothing, i.e. smoothing down corrugated printing material, e.g. by pressing means acting on wrinkled printing material}
- B41J 11/002: {Curing or drying the ink on the copy materials, e.g. by heating or irradiating}
- B41J 11/00216: {using infrared [IR] radiation or microwaves}
- B41J 11/0095: {Detecting means for copy material, e.g. for detecting or sensing presence of copy material or its leading or trailing end}
- G01N 19/10: Measuring moisture content, e.g. by measuring change in length of hygroscopic filament; Hygrometers
- B41J 2203/011: Inspecting the shape or condition, e.g. wrinkled or warped, of a medium to be printed before printing on it
- B41J: TYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS
- G01N: INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES (measuring or testing apparatus or processes other than immunoassay, involving enzymes or microorganisms C12M, C12Q)

## Abstract

In an ink jet printing apparatus of the present invention, a moisture content of a print sheet is estimated without decreasing productivity of the printing apparatus and appropriate conditions of printing operation in the subsequent printing process are specified. More specifically, by measuring a change in thickness of the print sheet after printing, a state of moisture content is estimated. Estimating a state of moisture content allows determination of appropriate conditions of printing operation such as a minimum drying time required for printing a high-quality image on various types of print sheets such as print coated paper or coated paper.

## Claims

### Claim 1

A method of estimating moisture content, said method comprising the steps of:
measuring a thickness of a medium to which liquid has been applied; and
estimating moisture content of the medium based on a change rate of the thickness of the medium.

### Claim 2 (depends on 1)

The method as claimed in claim 1, wherein the estimating step estimates the moisture content of the medium by using the thickness measured before the liquid is applied to the medium and after the liquid is applied to the medium.

### Claim 3 (depends on 1)

The method as claimed in claim 1, wherein the estimating step estimates the moisture content of the medium by using a thickness change that changes with elapsed time from applying the liquid to the medium.