JP2014083712A - Printer and printing method - Google Patents

Abstract

Color calibration of a printing apparatus is efficiently performed.
A printer 1 includes a head unit 40 that prints a plurality of patterns on a paper S, a detector 50 that reads the plurality of patterns printed on the paper S, and the head unit 40 and the detector 50 attached to the paper S. And the controller 10 that moves the controller 10, the controller 10 determines a printing order based on the characteristic values relating to the printing time and drying time of each pattern, and a plurality of head units 40 based on the determined order. The pattern is printed on the paper S.
[Selection] Figure 1

Description

  The present invention relates to a printing apparatus and a printing method.

A color printer is often used as a printing apparatus capable of expressing a plurality of colors. In such a color printer, calibration processing is performed to improve color reproducibility. When performing the calibration process, a patch sheet for calibration is printed. A plurality of patterns are printed on the patch sheet based on predetermined patch image data. For example, a patch sheet is used in which the gradation value is changed with a constant width over the entire gradation range for each ink color such as cyan, magenta, yellow, black, light cyan, and light magenta.
Then, as shown in Patent Document 1 below, a printed patch sheet pattern is measured to obtain a measurement value in the color space, and a color correction table for correcting a color shift output from the printer based on the result is created. doing.

JP 2005-184144 A

  However, since the pattern printed on the patch sheet ejects a larger amount of ink per unit area than a normal image, it takes time to dry the ink on the patch sheet. In order to perform accurate measurement, it is necessary to wait for the ejected ink to dry completely, and the waiting time until drying becomes longer, so the calibration process cannot be performed efficiently. It was.

  SUMMARY An advantage of some aspects of the invention is to solve at least a part of the problems described above, and the invention can be implemented as the following forms or application examples.

[Application Example 1]
A printing apparatus according to this application example includes a head unit that prints a plurality of patterns on a medium, a detector that reads the plurality of patterns printed on the medium, and the head unit and the detector with respect to the medium. And a controller for moving the controller, wherein the controller determines a printing order based on characteristic values relating to a printing time and a drying time of each of the patterns, and a plurality of the head units are arranged based on the determined order. The pattern is printed on the medium.

  According to such a configuration, the order in which the plurality of patterns is printed is determined based on the characteristic values relating to the printing time and the drying time of each pattern, and the plurality of patterns are printed on the medium based on the determined order. Is done. Accordingly, since the printing order is determined based on the characteristics of the printing time and the drying time, a plurality of patterns can be printed efficiently.

[Application Example 2]
In the printing apparatus according to the application example, the controller refers to a printing order characteristic table that indicates characteristics for determining the order in the printing time and the drying time, and a plurality of the printing order characteristic tables. It is preferable to include a printing order determining unit that determines the order in which the patterns are printed.

  According to such a configuration, the characteristics relating to the order in the printing time and the drying time can be described in the printing order characteristic table.

[Application Example 3]
In the printing apparatus according to the application example, the controller refers to the pattern combination table indicating a combination of the patterns according to a printing condition for printing the plurality of patterns, and the combination of the plurality of patterns with reference to the pattern combination table. It is preferable to include a pattern combination determining unit that determines

  According to such a configuration, a combination of patterns can be described in the pattern combination table in accordance with printing conditions for printing a plurality of patterns.

[Application Example 4]
In the printing apparatus according to the application example, the controller causes the detector to read each of the plurality of patterns printed based on the determined order, and a plurality of the patterns from a signal output by the detector. It is preferable to include a calibration processing unit that corrects a color correction table to be applied when printing an image based on a result of comparing the detected density with a reference density.

  According to such a configuration, it is possible to correct the color correction table applied when printing an image based on the printed pattern.

[Application Example 5]
The printing method according to this application example includes a pattern combination step of determining a combination of the patterns according to printing conditions for printing a plurality of patterns, a printing time of the pattern included in the combination determined in the pattern combination step, and A printing order determining step for determining the order in which the patterns are printed based on the characteristic values relating to the drying time; and a patch sheet printing step for printing a plurality of the patterns on a medium based on the order determined in the printing order determining step; It is characterized by providing.

  According to such a method, the order in which the plurality of patterns are printed is determined based on the characteristic values relating to the printing time and the drying time of each pattern, and the plurality of patterns are printed on the medium based on the determined order. Is done. Accordingly, since the printing order is determined based on the characteristics of the printing time and the drying time, a plurality of patterns can be printed efficiently.

1 is a block diagram showing a hardware configuration of a printer according to an embodiment of the present invention. 1 is a schematic perspective view of a printer according to an embodiment of the present invention. The figure explaining an optical sensor. The block diagram which shows the function structure for a calibration process. The flowchart explaining a calibration process.

  Embodiments of the present invention will be described below with reference to the drawings.

(Embodiment)
As the “printing apparatus”, an ink jet printer (hereinafter referred to as a printer) is assumed. The printing apparatus is not limited to an ink jet printer, and a line printer can also be assumed.
FIG. 1 is a block diagram illustrating a hardware configuration of the printer 1. FIG. 2 is a schematic perspective view of the printer 1. The printer 1 includes a controller 10, a transport unit 20, a carriage unit 30, a head unit 40, a detector 50, and a touch panel unit 70.
The controller 10 includes an interface unit (I / F) 11, a CPU 12, a memory 13, and a unit control circuit 14.

The printer 1 acquires image data via the interface unit 11 based on an operation from the touch panel unit 70 by a user, generates print data from the acquired image data, and forms a sheet as a medium based on the generated print data. Print on S and output. It is also possible to acquire print data generated by a computer (not shown) communicably connected via the interface unit 11, print it on a medium based on the acquired print data, and output it. .
A controller 10 in the printer 1 is for performing overall control in the printer 1. The interface unit 11 is assumed to be a network communication device, a memory card reading device, or the like. The CPU 12 is an arithmetic processing device for performing overall control of the printer 1, and controls each unit via the unit control circuit 14. The memory 13 is for securing an area for storing a program of the CPU 12, a work area, and the like.

The transport unit 20 feeds the paper S to a printable position and transports the paper S in the transport direction. The medium on which the printer 1 prints an image is not limited to paper, and may be, for example, cloth or film.
The carriage unit 30 is for moving the head 41 mounted on the carriage 31 in a moving direction that is a direction intersecting the transport direction of the paper S. Note that the intersecting direction is generally an orthogonal direction.

The head unit 40 is for ejecting ink onto the paper S and printing an image, and has a head 41. Although illustration is omitted, a number of nozzles for ejecting ink are provided on the lower surface of the head 41, and a nozzle row is formed for each color of ejected ink. For example, a black nozzle row that discharges black ink K, a cyan nozzle row that discharges cyan ink C, a magenta nozzle row that discharges magenta ink M, a yellow nozzle row that discharges yellow ink Y, and the like are formed on the lower surface of head 41. Is formed.
In each nozzle row, a large number of nozzles are arranged at predetermined intervals in the transport direction. The ink discharge method from the nozzle may be a piezo method in which ink is discharged from the nozzle by expanding and contracting the ink chamber by applying a voltage to the drive element (piezo element), or using a heating element in the nozzle. A thermal method in which bubbles are generated and ink is ejected from the nozzles by the bubbles may be used.

  The detector 50 is for monitoring the situation in the printer 1 and outputting the detection result to the controller 10. In the present embodiment, the detector 50 includes an optical sensor 51. The optical sensor 51 is used to detect the distance from the nozzle surface of the head 41 to the paper S, the width of the paper S, and the density of the pattern printed on the paper S.

  In the printer 1 having such a configuration, the controller 10 transports the paper S to the downstream side in the transport direction by the discharge operation of discharging the ink from the nozzles while moving the head 41 in the moving direction by the carriage 31. Repeat the transfer operation. As a result, since dots are formed by the subsequent ejection operation at positions different from the positions of the dots formed by the previous ejection operation, a two-dimensional image is printed on the paper S.

  FIG. 3 is a diagram illustrating the optical sensor 51. The optical sensor 51 is attached to the carriage 31 and can move in the moving direction. The optical sensor 51 is attached at a position downstream of the head 41 in the transport direction, and can move on an image printed by the head 41. The optical sensor 51 includes a light emitting unit 52 and a light receiving unit 53, the light emitting unit 52 includes a light emitting element 52a and a drive circuit 52b, and the light receiving unit 53 includes a light receiving element 53a, an amplification circuit 53b, and an AD conversion circuit 53c.

The light emitting element 52a is for irradiating the paper S with light, and examples thereof include a light emitting diode (LED), a laser diode, and an incandescent bulb. Note that an irradiation region when the irradiation light from the light emitting element 52 a is focused on the surface of the paper S is referred to as a spot 55.
The drive circuit 52b controls the drive current of the light emitting element 52a according to the light amount adjustment value which is a control signal received from the controller 10, and adjusts the light emission amount of the light emitting element 52a.
That is, the light emitting unit 52 can adjust the light emission amount by inputting the light amount adjustment value.

The light receiving element 53a is a photoelectric conversion element that receives the light reflected from the light emitting element 52a toward the paper S and reflected by the paper S, and generates a current according to the received light quantity. For example, a photodiode is assumed as the light receiving element 53a.
The amplifier circuit 53b is for converting the output current from the light receiving element 53a into a voltage and amplifying it. The AD conversion circuit 53 c AD converts the output voltage from the amplification circuit 53 b and outputs a reflected light amount value that is a digital value corresponding to the reflected light amount from the paper S to the controller 10.
That is, the light receiving unit 53 receives the reflected light of the light emitted from the light emitting unit 52 and outputs a reflected light amount value corresponding to the received light amount.

  The amount of reflected light (the intensity of the reflected light) received by the light receiving unit 53 varies depending on the color density at the reflection position of the paper S. Therefore, the density of the image can be detected based on the result of the light emitting unit 52 irradiating light toward the image printed on the paper S and the light receiving unit 53 receiving the reflected light from the image. Therefore, the optical sensor 51 can function as a concentration detector.

  Next, the calibration process will be described. Due to an error in the amount of ink discharged from the head 41, the color output characteristics differ between the individual printers 1. Even in the same printer, the color output characteristics may change due to changes over time. Calibration processing (density correction processing) is performed to correct the color output characteristic difference and improve the color reproducibility of the printer 1.

  The calibration processing is a result of the printer 1 outputting a patch sheet PS (see FIG. 4) on which a plurality of density measurement patterns (hereinafter referred to as patterns) are printed on the paper S and reading the density of the pattern. In this processing, a correction value is set based on the deviation from the target density, and correction is performed based on the correction value so that the image density printed by the printer 1 approaches the target density. For example, when the pattern reading density is lighter than the target density, the correction value is set so that the amount of ink discharged from the head 41 is increased. Conversely, when the pattern reading density is higher than the target density, the ink from the head 41 is set. A correction value is set so that the discharge amount is reduced. As a result, the image density printed by the printer 1 can be brought close to the target density, and the color reproducibility of the printer 1 can be improved. The detailed content of the density calibration process is not the gist of the present invention, and is therefore omitted (see, for example, Japanese Patent Application Laid-Open No. 2008-160340 for such a processing method).

FIG. 4 is a block diagram illustrating a functional configuration for calibration processing in the printer 1. FIG. 5 is a flowchart for explaining the calibration process. In this embodiment, the pattern is described for density correction, but the application of the pattern is not limited.
The printer 1 includes a creation condition input unit 100, a printing unit 130, and a density detection unit 140. Further, the controller 10 includes a creation condition acquisition unit 110, a pattern combination determination unit 112, a print order determination unit 114, a print data generation unit 116, a pattern combination table 118, a print order characteristic table 120, a color correction table 122, and a calibration processing unit. 124 is provided.

In the present embodiment, the creation condition input unit 100 assumes a touch panel unit 70. The printing unit 130 is assumed to be the transport unit 20, the carriage unit 30 and the head unit 40, and the density detection unit 140 is assumed to be the detector 50. Each functional unit included in the controller 10 realizes a function by the cooperation of hardware such as the CPU 12 and the memory 13 and software stored in the memory 13.
When the calibration process is started, the creation condition acquisition unit 110 acquires the creation information of the patch sheet PS input by the creation condition input unit 100 (step S200). In the present embodiment, the creation information is assumed to be media information, resolution information, and ink set information indicating a combination of colors. The creation information acquired by the creation condition acquisition unit 110 is sent to the pattern combination determination unit 112. That is, if any of the medium type, resolution, and color used for printing changes, the combination of patterns used for calibration processing changes, and the creation information of the patch sheet PS also changes.

The pattern combination determination unit 112 determines a pattern combination based on the creation information sent from the creation condition acquisition unit 110 (step S202) <pattern combination step>. In the present embodiment, a pattern combination is determined with reference to a pattern combination table 118 that is determined in advance and stored in the memory 13. Information on the pattern combination determined by the pattern combination determination unit 112 is sent to the printing order determination unit 114.
The print order determining unit 114 acquires the pattern combination information sent from the pattern combination determining unit 112 and determines the print order of each pattern by referring to the print order characteristic table 120 that is determined in advance and stored in the memory 13. (Step S204) <Print Order Determination Step> Information regarding the determined printing order is sent to the print data generation unit 116.

In the present embodiment, the printing order characteristic table 120 is a table for calculating characteristic values in consideration of ink drying time and printing time. The ink drying time is determined based on, for example, the amount of ink applied, the length of the ink drying time, and the dot size. Specifically, the larger the ink ejection amount, the longer the drying time as the ink characteristics, and the longer the dot size, the longer the drying time. In addition, for the printing time, for example, the characteristic value is determined based on the resolution level, the number of passes, and the carriage speed. Specifically, the higher the resolution, the greater the number of passes, and the higher the carriage speed, the longer the printing time.
The ink drying time characteristic value and the printing time characteristic value are added together, and the printing order of each pattern is determined based on the magnitude of the added value. In this case, the pattern printing order is determined so that the density detection process of the printed patch sheet PS can be started early.

For example, the order in which a pattern with a short print time is printed first so as to have a low resolution and few passes may be determined. Alternatively, the order in which a pattern with a small amount of ink to be printed or a color pattern is printed first may be determined. Further, the order in which a color pattern with a short drying time due to a small amount of moisturizing agent is printed first may be determined from the ink composition.
Alternatively, a pattern with a large ink ejection amount may be printed first, and drying may be started before a pattern with a small ink ejection amount.
The print data generation unit 116 generates print data in which each pattern is arranged based on the print order sent from the print order determination unit 114 (step S206). The generated print data is sent to the printing unit 130, and a patch sheet PS in which patterns arranged in the determined order are arranged in multiple stages is printed (step S208) <patch sheet printing process>.

The patch sheet PS printed by the printing unit 130 is set at a position where the density detection unit 140 can read after drying the ink of the pattern. The density detector 140 detects the density of the pattern on the set patch sheet PS (step S210). The pattern density information detected by the density detector 140 is sent to the calibration processor 124.
The calibration processing unit 124 compares the pattern density with the reference density (step S212), and corrects the color correction table 122 that is determined in advance and held in the memory 13 based on the comparison result (step S214). ). The color correction table 122 is referred to when the print data generation unit 116 prints an image, and is applied as correction data when the image data is color-converted.

According to the embodiment described above, the following effects can be obtained.
(1) A pattern for calibration processing is determined according to the medium that is the printing medium and the printing resolution, and printing is performed on the patch sheet PS based on the drying time of the ink used in the pattern and the printing time for printing the pattern. Since the pattern arrangement to be determined is determined, the throughput of the calibration process is improved.
(2) When reading the pattern printed on the patch sheet PS, the pattern is printed so that the ink of the pattern is already dry, so that the density of the pattern can be measured with high accuracy.
An apparatus that implements the above-described method may be realized by a single apparatus or may be realized by combining a plurality of apparatuses, and includes various aspects.
For example, if any of the medium type, resolution, and color used for printing changes, the creation information of the patch sheet PS is changed. However, the creation information of the patch sheet PS may be changed by focusing on only one of them. .
Each configuration in each embodiment and a combination thereof are examples, and addition, omission, replacement, and other changes of the configuration can be made without departing from the spirit of the present invention. In addition, the present invention is not limited to the embodiments, and is limited only by the scope of the claims.

  DESCRIPTION OF SYMBOLS 1 ... Printer, 10 ... Controller, 11 ... Interface part, 12 ... CPU, 13 ... Memory, 14 ... Unit control circuit, 20 ... Conveyance unit, 30 ... Carriage unit, 31 ... Carriage, 40 ... Head unit, 41 ... Head, DESCRIPTION OF SYMBOLS 50 ... Detector, 51 ... Optical sensor, 52 ... Light emission part, 52a ... Light emission element, 52b ... Drive circuit, 53 ... Light reception part, 53a ... Light reception element, 53b ... Amplification circuit, 53c ... AD conversion circuit, 55 ... Spot, DESCRIPTION OF SYMBOLS 70 ... Touch panel unit, 100 ... Creation condition input part, 110 ... Creation condition acquisition part, 112 ... Pattern combination determination part, 114 ... Print order determination part, 116 ... Print data generation part, 118 ... Pattern combination table, 120 ... Print order Characteristic table 122 ... color correction table 124 ... calibration Processing section, 130 ... printing unit, 140 ... concentration detection unit, S ... paper, PS ... patch sheet.

Claims (5)

A head unit for printing a plurality of patterns on a medium;
A detector for reading a plurality of the patterns printed on the medium;
A controller for moving the head unit and the detector relative to the medium, and
The controller determines a printing order based on a characteristic value related to a printing time and a drying time of each of the patterns, and causes the head unit to print a plurality of the patterns on the medium based on the determined order. A printing apparatus characterized by that. The printing apparatus according to claim 1,
The controller is
A printing order characteristic table respectively showing characteristics for determining the order in the printing time and the drying time;
A printing apparatus comprising: a printing order determining unit that refers to the printing order characteristic table and determines the order of printing the plurality of patterns. The printing apparatus according to claim 1,
The controller is
A pattern combination table showing combinations of the patterns according to printing conditions for printing a plurality of the patterns;
A printing apparatus comprising: a pattern combination determination unit that refers to the pattern combination table and determines a combination of a plurality of the patterns. The printing apparatus according to any one of claims 1 to 3,
The controller is
Each of the plurality of patterns printed based on the determined order is read by the detector, the density of the plurality of patterns is detected from a signal output from the detector, and the detected density and reference density are detected. And a calibration processing unit that corrects a color correction table to be applied when printing an image based on the result of the comparison. A pattern combination step of determining a combination of the patterns according to printing conditions for printing a plurality of patterns;
A printing order determination step for determining the order in which the patterns are printed based on characteristic values relating to the printing time and drying time of the patterns included in the combination determined in the pattern combination step;
A patch sheet printing step of printing a plurality of the patterns on a medium based on the order determined in the printing order determination step.

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