Ink-Jet Printer and Method of Performing Printing

• US 20160288527A1
• Filed: 03/31/2016
• Published: 10/06/2016
• Est. Priority Date: 03/31/2015
• Status: Active Grant

• Current Assignee: Brother Kogyo Kabushiki Kaisha
• Original Assignee: Brother Kogyo Kabushiki Kaisha
• Inventors: Ogawa, Masanobu, Hasegawa, Shin, Nodsu, Tomohiro, Kanzaki, Shotaro, Someya, Masaru, Sugahara, Hiroto
• Granted Patent: US 9,487,018 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: B41J 2/2103 Features not dealing with the colouring process per se, e.g. construction of printers or heads, driving circuit adaptations
• CPC Class Codes: B41J 2/2139 Compensation for malfunctioning nozzles creating dot place or dot size errors generating single droplets or particles on demand by pressure, e.g. electromechanical transducers B41J2/045
• CPC Class Codes: H04N 1/603 controlled by characteristics of the picture signal generator or the picture reproducer
• CPC Class Codes: H04N 1/6036 involving periodic tests or tests during use of the machine

Abstract

An ink-jet printer, including a density detector and a controller, wherein, where successive three ejecting operations to be repeatedly performed on the same predetermined region of a recording medium are defined as first through third ejecting operations in the order of performance, the controller executes: a process for detecting a color density of the predetermined region immediately after attachment of the ink ejected in the second ejecting operation; a process for calculating, based on the detected color density, an estimated density after fixation of the ink ejected in the second ejecting operation; a process for calculating, based on print data, an ideal density after fixation of the ink ejected in the second ejecting operation; and a process for correcting the print data based on a difference between the estimated density and the ideal density, and wherein the ink-jet printer performs the third ejecting operation based on the corrected print data.

Claims

1. An ink-jet printer, comprising:

an ink-jet head configured to eject ink from a plurality of nozzles while moving in a scanning direction;

a conveyor configured to convey a recording medium in a conveyance direction orthogonal to the scanning direction;

a density detector configured to move with the ink-jet head in the scanning direction for detecting a color density which is a density of a color on a surface of the recording medium; and

a controller configured to control the ink-jet head, the conveyor, and the density detector,

wherein the controller controls the ink-jet printer such that the ink-jet printer repeatedly and alternately performs an ejecting operation in which the ink-jet head ejects the ink from the nozzles based on print data while moving in the scanning direction and a conveying operation in which the conveyor conveys the recording medium, so that printing is repeatedly performed on the same predetermined region of the recording medium in a plurality of ejecting operations performed at least three times,

wherein, where successive three ejecting operations among the plurality of ejecting operations are defined as a first ejecting operation, a second ejecting operation, and a third ejecting operation in the order of performance, the controller executes;

a density detecting process for controlling the density detector to detect the color density of the predetermined region immediately after the ink ejected in the second ejecting operation has been attached to the predetermined region;

an estimated density calculating process for calculating, based on the color density detected in the density detecting process, an estimated density which is an estimated value of the color density of the predetermined region after fixation of the ink ejected in the second ejecting operation;

an ideal density calculating process for calculating, based on the print data, an ideal density which is an ideal value of the color density of the predetermined region after fixation of the ink ejected in the second ejecting operation; and

a correcting process for correcting the print data based on a difference between the estimated density and the ideal density, and

wherein the controller controls the ink-jet printer to perform the third ejecting operation based on the print data corrected in the correcting process.

2. The ink-jet printer according to claim 1, further comprising a storage in which are stored estimation data to be used for estimating, based on the color density detected by the density detector, the color density after fixation of the ink,

wherein a plurality of first estimation data are stored in the storage in connection with an ink fixing time condition which relates to an ink fixing time,

wherein the controller further executes a first data selecting process for selecting one first estimation data from among the plurality of the first estimation data in accordance with the ink fixing time condition, and

wherein the controller calculates the estimated density in the estimated density calculating process based on the color density detected in the density detecting process and the one first estimation data selected in the first data selecting process.

3. The ink-jet printer according to claim 2,

wherein the ink fixing time condition includes a condition relating to a type of the recording medium,

wherein the controller further executes a type obtaining process for obtaining the type of the recording medium, and

wherein the controller selects, in the first data selecting process, the one first estimation data in accordance with the type of the recording medium.

4. The ink-jet printer according to claim 2, further comprising a temperature sensor for detecting a temperature around the recording medium,

wherein the fixing time condition includes a condition relating to the temperature around the recording medium, and

wherein the controller selects, in the first data selecting process, the one first estimation data in accordance with the temperature detected by the temperature sensor.

5. The ink-jet printer according to claim 2, further comprising a humidity sensor for detecting a humidity around the recording medium,

wherein the fixing time condition includes a condition relating to the humidity around the recording medium, and

wherein the controller selects, in the first data selecting process, the one first estimation data in accordance with the humidity detected by the humidity sensor.

6. The ink-jet printer according to claim 2,

wherein, aside from the plurality of the first estimation data, a plurality of second estimation data are stored in the storage in connection with attached amount information which is information relating to an attached mount of the ink per unit area of the recording medium,

wherein the controller further executes:

an attached amount information obtaining process for obtaining the attached amount information in the predetermined region based on the print data; and

a second data selecting process for selecting one second estimation data from among the plurality of the second estimation data in accordance with the attached amount information in the predetermined region, and

wherein the controller calculates, in the estimated density calculating process, the estimated density based on the color density detected in the density detecting process, the one first estimation data selected in the first data selecting process, and the one second estimation data selected in the second data selecting process.

7. The ink-jet printer according to claim 1,

wherein the controller further executes a region specifying process for specifying, based on the print data, a high-density region among a plurality of divided regions which are obtained by dividing the predetermined region in the scanning direction, the high-density region having a dot occupation ratio higher than a predetermined threshold, the dot occupation ratio indicating the number of ink dots to be attached per unit area,

wherein the controller controls the density detector to detect the color density of the high-density region in the density detecting process, and

wherein the controller calculates the ideal density of the high-density region in the ideal density calculating process.

8. The ink-jet printer according to claim 7,

wherein, where a plurality of the high-density regions are present, the controller specifies, in the region specifying process, one high-density region among the plurality of the high-density regions which has the smallest number of successively adjacent blank dots to each of which the ink is not attached,

wherein the controller controls the density detector to detect the color density of the one high-density region in the density detecting process, and

wherein the controller calculates the ideal density of the one high-density region in the ideal density calculating process.

9. The ink-jet printer according to claim 1,

wherein the ink-jet head ejects the ink in mutually different colors from the plurality of nozzles,

wherein the controller further executes a dot occupation ratio obtaining process for obtaining, based on the print data, a dot occupation ratio in the predetermined region for each of the colors, the dot occupation ratio being the number of ink dots to be attached per unit area,

wherein the controller controls, in the density detecting process, the density detector to detect the color density of one of the colors having the highest dot occupation ratio in the predetermined region, and

wherein the controller calculates, in the ideal density calculating process, the ideal density for the one of the colors having the highest dot occupation ratio in the predetermined region.

10. The ink-jet printer according to claim 9,

wherein the density detector is configured to emit light toward the recording medium and to receive light reflected on the recording medium, so as to detect the color density on the surface of the recording medium, and

wherein, in the density detecting process, the controller controls the density detector to emit, toward the predetermined region, light whose color is a complementary color for the one of the colors having the highest dot occupation ratio and to detect the color density of the one of the colors in the predetermined region.

11. The ink-jet printer according to claim 9, wherein, in the correcting process, the controller corrects print data for the respective colors in proportions of the dot occupation ratios of the respective colors, based on the difference between the estimated density and the ideal density for the one of the colors having the highest dot occupation ratio.

12. A method of performing printing by an ink-jet printer, comprising:

an ejecting step of ejecting ink from a plurality of nozzles of an ink-jet head based on print data while moving the ink-jet head in a scanning direction; and

a conveying step of conveying, by a conveyor, a recording medium in a conveyance direction orthogonal to the scanning direction,

wherein the ejecting step and the conveying step are repeatedly and alternately executed, so that printing is repeatedly performed on the same predetermined region of the recording medium by a plurality of ejecting steps executed at least three times,

wherein, where successive three ejecting steps among the plurality of ejecting steps are defined as a first ejecting step, a second ejecting step, and a third ejecting step in the order of execution, the method further comprising;

a density detecting step of detecting the color density of the predetermined region immediately after the ink ejected in the second ejecting step has been attached to the predetermined region, by a density detector configured to move with the ink-jet head in the scanning direction for detecting the color density on the surface of the recording medium;

an estimated density calculating step of calculating, based on the color density detected in the density detecting step, an estimated density which is an estimated value of the color density of the predetermined region after fixation of the ink ejected in the second ejecting step;

an ideal density calculating step of calculating, based on the print data, an ideal density which is an ideal value of the color density of the predetermined region after fixation of the ink ejected in the second ejecting step; and

a correcting step of correcting the print data based on a difference between the estimated density and the ideal density,

wherein the ink is ejected from the nozzles based on the corrected print data in the third ejecting step.