JP2019113494A - Spectroscopy measuring device, electronic apparatus, and spectroscopy measuring method - Google Patents

Abstract

To provide a spectroscopy measuring device, capable of increasing degree of freedom of placement position of a reference object, an electronic apparatus and a spectroscopy measuring method.SOLUTION: The spectroscopy measuring device includes a spectroscope 17 for measuring the amount of light relevant to a plurality of wavelengths of light from an object, and an arithmetic unit 154 that calculates the reflection rate of the object on the basis of the measurement result of the amount of light with respect to the plurality of wavelengths. The arithmetic unit calculates the reflection rate of the object by applying transformation matrix for converting the measurement result into the reflection rate to the measurement result.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a spectrometry apparatus, an electronic device, and a spectrometry method.

  BACKGROUND Conventionally, an analyzer that measures the light characteristics of each wavelength of incident light is known (see, for example, Patent Document 1).

  In the spectrometer of Patent Document 1, a light source unit irradiates light to an object, and light reflected by an inspection object is dispersed into a plurality of measurement wavelengths to generate a measurement spectrum. Then, the spectrum of the object can be accurately estimated by applying a transformation matrix determined from the light whose spectrum is known to the obtained measurement spectrum.

JP, 2013-142656, A

By the way, the above-described apparatus may be provided in a printing apparatus and used as a colorimetry apparatus that measures the color of an object printed on a medium. When measuring the color of an object, it is necessary to measure the reflectance of the object. Generally, when measuring the reflectance, a reference plate is used for calibration. In the device described in Patent Document 1, as described above, the spectrum of the object can be estimated from the measured spectrum, but in order to calculate the reflectance of the object from the estimated spectrum, it is configured with a reference color (for example, white) It is necessary to measure the reference plate (white plate).
However, in order to perform high-accuracy measurement, it is necessary to equalize the conditions at the time of color measurement of a reference object (for example, a reference plate) and at the time of color measurement of an object formed on a medium. Therefore, it is necessary to place the reference object at the same height as the medium, and it is necessary to secure the placement position of the reference object. That is, the degree of freedom of the arrangement position of the reference object is reduced.

  An object of the present invention is to provide a spectrometry device, an electronic device, and a spectrometry method which can increase the freedom of the arrangement position of a reference object.

  A spectrometry apparatus according to an application example of the present invention includes a spectroscope for measuring light quantities for a plurality of wavelengths of light from an object, and a reflectance of the object based on measurement results of the light quantities for the plurality of wavelengths. A calculating unit is provided, and the calculating unit is characterized in that a conversion matrix for converting the measurement result into a reflectance is applied to the measurement result to calculate the reflectance of the object.

  In this application example, the calculation unit causes the conversion matrix that converts the measured value to the reflectance to act on the measured value measured by the spectroscope to calculate the reflectance of the object. That is, the reflectance is directly calculated from the measured value measured by the spectroscope. Therefore, when calculating the reflectance of the object, it is not necessary to measure the reflectance of the reference color using a reference object (for example, a reference plate), and the conditions at the time of color measurement are equalized between the reference object and the object. There is no need. Therefore, the reference object does not have to be disposed at the same height as the object, and the degree of freedom in the arrangement of the reference object can be increased.

In the spectrometry device of this application example, the conversion matrix is a reflectance for k (k is a natural number) wavelengths of a sample whose reflectance is known, and m (m when the sample is measured by the spectrometer. Is preferably a matrix calculated using measurement results for natural wavelengths).
In this application example, the conversion matrix is calculated from the reflectances for k wavelengths of the sample whose reflectance is known and the measurement results for m wavelengths when the sample is measured by a spectroscope. Therefore, the conversion matrix can be calculated by measuring a sample whose reflectance is known by using a spectroscope. That is, if a sample whose reflectance is known is prepared, the transformation matrix can be calculated without using a special device. Therefore, it is possible to easily calculate a transformation matrix for directly calculating the reflectance from the measurement values measured by the spectroscope.

In the spectrometer of this application example, a matrix of known reflectances for the k wavelengths in each of n (n is a natural number) different samples of different colors is denoted by S _{n, k} by the spectrometer. Let D _{n, m} be a matrix of measurement results of light quantity for the m wavelengths in each of the n samples to be measured, let M s be the conversion matrix, and F (M s) be an evaluation function F (M s) It is preferable that the transformation matrix Ms be a matrix that minimizes the evaluation function F (Ms), as = | S _{n, k} -MsD _{n, m} | ² .
In this application example, the transformation matrix Ms is a matrix that minimizes the evaluation function F (Ms) derived from the matrix S _{n, k} of reflectance and the matrix D _{n, m} of the measurement result. That is, the transformation matrix Ms is a matrix in which S _{n, k} and Ms · D _{n, m} match. Therefore, the transformation matrix Ms can be determined by expanding the evaluation function F (Ms) in the same manner as a general least squares error solution. Therefore, it is possible to easily determine the transformation matrix Ms for directly calculating the reflectance from the measurement values measured by the spectroscope.

In the spectrometer of this application example, a matrix of known reflectances for the k wavelengths in each of n samples having different colors is denoted by S _{n, k,} and the _n measured by the spectrometer _Let D _{n, m} be a matrix of measurement results of light quantity for the m wavelengths in each of the samples, _{let the} conversion matrix be Ms, and let the conversion term be β · Ms ^T · Ms. Let the evaluation function F (Ms) be F (Ms) = | S _{n, k} −Ms · D _{n, m} | ² + β · Ms ^T · Ms, the transformation matrix Ms has the minimum evaluation function F (Ms) It is preferable that the matrix be
Here, β is a constant called a hyperparameter, and T displayed on the right shoulder of the transformation matrix Ms indicates that it is a transposed matrix.
In this application example, by adding βMs ^T Ms, which is a multiplier term, to the evaluation function F (Ms), it is possible to calculate a transformation matrix in which overfitting is suppressed.
That is, in the evaluation function F (Ms), when such a multiplier term is not added, the best linear unbiased estimation under the condition that the matrix S _{n, k} and the matrix D _{n, m} do not include an error. It is possible to calculate a transformation matrix Ms capable of calculating the reflectance as a quantity. However, if an error is included in the matrix S _{n, m} or the matrix D _{n, m} , depending on the degree, it becomes a parameter of the over-fitting state. In this case, the parameters of the transformation matrix Ms determined by expanding this evaluation function F (Ms) will be obtained as a mixture of very large values and small values, and the variation of the parameters will be large. . In this case, when the conversion matrix is applied to the measurement value of the measurement result by the spectroscope to calculate the reflectance, if the measurement value of the measurement result is a measurement value including an error similar to that at the calculation of the conversion matrix, Although the reflectance can be determined with high accuracy, the estimation accuracy of the reflectance is lowered (over fitting) depending on the degree of the error included in the measurement value of the measurement result and the variation.
On the other hand, in this application example, as described above, the variance (or Euclidean norm) of the parameters of the transformation matrix Ms is minimized by adding the multiplier term βMs ^T Ms to the evaluation function F (Ms). Can be regularized. This makes it possible to reduce variations in the parameters of the conversion matrix Ms, and to calculate a conversion matrix that can suppress overfitting. That is, when the measured value of the measurement result is converted to the reflectance using the conversion matrix Ms, the reflectance can be calculated with high accuracy even if there is a variation in the error included in the measured value.

In the spectrometry device of this application example, the calculation unit measures the measurement results for m wavelengths when a sample whose reflectance is known by the spectrometer is measured, and the reflectances of k wavelengths of the sample Preferably, the transformation matrix is calculated using
In this application example, the calculation unit calculates a transformation matrix from the measurement results of the sample whose reflectance is known and the reflectance of the sample. In this way, when a spectrometer having such an operation unit prepares a sample having a known reflectance, it is possible to calculate a transformation matrix for directly calculating the reflectance from the measurement value measured by the spectrometer. Can. Therefore, for example, when the light source or the like changes over time due to long-term use of the spectrometry device, it is possible to calculate the conversion matrix in that state, and to calculate the reflectance of the object accurately.

The spectrometer according to the application example further includes a reference, and the calculation unit is configured to measure the spectroscope based on the measurement result of the reference by the spectrometer when the reference is irradiated with light from a light source. It is preferable to correct the measurement result when measuring the object according to
In this application example, the computing unit corrects the measurement result of the object based on the measurement result of the reference object (for example, the reference plate). Thus, for example, even if the light amount of the light source of the spectroscope changes, the measurement result of the target is corrected based on the measurement result of the reference object measured in the state where the light amount of the light source changes. Can be eliminated. Therefore, the reflectance of the object can be calculated accurately.

The spectrometry device of this application example further includes a temperature measurement unit that measures the temperature of the spectrometer, and the calculation unit is configured to measure the object with the spectrometer based on the temperature measured by the temperature measurement unit. It is preferable to correct the measurement result at the time of measurement.
In the application example, the calculation unit corrects the measurement result of the object based on the temperature measured by the temperature measurement unit. Thereby, for example, even if the characteristic of the spectroscopic device of the spectrometer is changed due to the temperature change, if the relationship between the characteristic of the spectroscopic device or the like and the temperature is obtained in advance, the change of the characteristic is measured by the measured temperature. It can be grasped. Therefore, the correction can be performed according to the change of the characteristic, and the reflectance of the object can be calculated with high accuracy.

An electronic device according to an application example of the present invention is characterized by including the above-described spectrometry device and a control unit that controls the arithmetic unit.
In this application example, since the above-described spectrometer is provided, when the reflectance is calculated from the measurement value measured by the spectrometer, it is necessary to measure the reference color using a reference object (for example, a reference plate) There is no As a result, it is not necessary to equalize the measurement conditions for the reference object and the object. Therefore, the reference object does not have to be disposed at the same height as the object, and the degree of freedom in the arrangement of the reference object can be increased.

In the spectrometry method according to an application example of the present invention, the spectroscope measures the light quantity for a plurality of wavelengths of light from the object, and the operation unit converts the measurement result of the light quantity for the plurality of wavelengths into a reflectance. A matrix is applied to the measurement result to calculate the reflectance of the object.
In this application example, the same effects as those of the above-described spectrometer can be obtained, and it is not necessary to arrange the reference object (for example, the reference plate) at the same height as the object, and the freedom of arrangement of the reference object Can be raised.

FIG. 1 is an external view showing a schematic configuration of a printer of a first embodiment. FIG. 1 is a block diagram showing a schematic configuration of a printer according to a first embodiment. FIG. 2 is a plan view showing a schematic configuration of a carriage of the first embodiment. Sectional drawing which shows schematic structure of the spectrometer of 1st embodiment. Sectional drawing which shows schematic structure of the carriage of 1st embodiment. FIG. 2 is a block diagram showing a functional configuration of a CPU of the printer of the first embodiment. 6 is a flowchart showing conversion matrix calculation processing in the printer of the first embodiment. 5 is a flowchart showing an example of correction processing in the printer of the first embodiment. 6 is a flowchart showing reference plate measurement processing in the printer of the first embodiment. 6 is a flowchart showing reflectance calculation processing in the printer of the first embodiment. The graph which shows the correlation of the initial value of light reception amount, and a measured value at the time of measuring-processing the reference | standard board in the printer of 1st embodiment. The graph which shows the inclination of the measured value to the initial value of the light reception amount at the time of measuring-processing the reference | standard board in the printer of 1st embodiment.

First Embodiment
Hereinafter, a first embodiment according to the present invention will be described based on the drawings. In the present embodiment, a printer 1 (ink jet printer) including a spectrometry device will be described below as an example of the electronic device of the present invention.

[Schematic Configuration of Printer]
FIG. 1 is a perspective view showing a configuration example of the appearance of the printer 1 of the present embodiment. FIG. 2 is a block diagram showing a schematic configuration of the printer 1 of the present embodiment. FIG. 3 is a plan view showing a schematic configuration of the carriage 13 of the printer 1 of the present embodiment.
As shown in FIG. 1, the printer 1 corresponds to the electronic device of the present invention, and controls the unit housing 10, the supply unit 11, the transport unit 12, the carriage 13, the carriage movement unit 14, and the present invention. A control unit 15 (see FIG. 2) corresponding to a unit and a maintenance unit 20 are provided. Further, as shown in FIG. 3, the carriage 13 is provided with a printing unit 16, a spectroscope 17, and a shutter mechanism 19 for protecting the spectroscope 17 from foreign matters such as ink mist.

The printer 1 configured in this way controls the units 11, 12, and 14 and the carriage 13 based on print data input from an external device 30 such as a personal computer, for example, and prints an image on the medium M. . As this image, for example, a correction pattern for correcting uneven density can be used. The printer 1 measures the correction pattern by the spectroscope 17 and performs various correction processes such as correction of color misregistration based on the color measurement result of the correction pattern.
Hereinafter, each configuration of the printer 1 will be specifically described.

The unit housing 10 is provided with units 11, 12, 14, 15, 20 and a carriage 13. The unit housing 10 is located on the + Z side, and has a bottom surface portion 101 on which the transport unit 12 and the maintenance unit 20 are disposed, and a first side surface portion 102 and a second side surface portion 103 rising from the bottom surface portion 101 in the −Z direction. , And the back part 104. The first side surface portion 102 is located on the −X side, the second side surface portion 103 is located on the + X side, and the back surface portion 104 is between the first side surface portion 102 and the second side surface portion 103 along the X direction. To position.
Here, the first side surface portion 102 is a surface on which a first end portion 194 of the shutter mechanism 19 described later abuts, and the second side surface portion 103 is a surface on which the second end portion 195 of the shutter mechanism 19 abuts. . Although not shown, the printer 1 includes an outer housing that covers at least a part of the unit housing 10.

The supply unit 11 is a unit for supplying a medium M (in the present embodiment, an example of a sheet of paper), which is an object of the present invention, to an image forming position. The supply unit 11 includes, for example, a roll body 111 (see FIG. 1) on which the medium M is wound, a roll drive motor (not shown), a roll drive wheel train (not shown), and the like. Then, based on the command from the control unit 15, the roll drive motor is rotationally driven, and the rotational force of the roll drive motor is transmitted to the roll body 111 via the roll drive wheel train. Thereby, the roll body 111 rotates, and the paper wound around the roll body 111 is supplied to the downstream side (+ Y direction) in the Y direction (sub scanning direction).
In the present embodiment, an example in which the paper wound around the roll body 111 is supplied is shown, but the present invention is not limited to this. For example, the media M may be supplied by any supply method such as supplying the media M such as paper stacked on a tray or the like, for example, one by one by a roller or the like.

The transport unit 12 transports the medium M supplied from the supply unit 11 along the Y direction. The conveyance unit 12 includes a driven roller (not shown) disposed at a position where the medium M is sandwiched between the conveyance roller 121 and the conveyance roller 121 and driven by the conveyance roller 121, and a platen 122.
When the driving force from the conveyance motor (not shown) is transmitted to the conveyance roller 121 and the conveyance motor is driven by the control of the control unit 15, the conveyance roller 121 is rotationally driven by its rotational force and the medium M is interposed between it and the driven roller. The sheet is conveyed along the Y direction in a pinched state. Further, on the downstream side (+ Y side) of the transport roller 121 in the Y direction, a platen 122 facing the carriage 13 is provided.

The carriage 13 is a housing on which the printing unit 16 that discharges ink to the medium M to print an image, the spectroscope 17 that measures the color of the image on the medium M, and the shutter mechanism 19 are mounted. .
The carriage 13 is moved by the carriage moving unit 14 along the main scanning direction (X direction). The detailed configurations of the carriage 13, the printing unit 16, the spectroscope 17, and the shutter mechanism 19 will be described later.
In the following description, the −X side in the main scanning direction (X direction) may be referred to as the Home side, and the + X side may be referred to as the Full side. Here, Home is a position at which the carriage 13 is retracted to a standby state in which printing processing is not performed. Also, Full is opposite to Home.

The carriage moving unit 14 reciprocates the carriage 13 along the X direction based on a command from the control unit 15.
The carriage moving unit 14 includes, for example, a carriage guide shaft 141, a carriage motor 142, and a timing belt 143, as shown in FIG.
The carriage guide shaft 141 is disposed along the X direction, and both ends thereof are fixed to, for example, a housing of the printer 1. The carriage motor 142 drives the timing belt 143. The timing belt 143 is supported substantially parallel to the carriage guide shaft 141, and a part of the carriage 13 is fixed. Then, when the carriage motor 142 is driven based on the command of the control unit 15, the timing belt 143 moves forward and backward, and the carriage 13 fixed to the timing belt 143 is guided by the carriage guide shaft 141 to reciprocate.

  The maintenance unit 20 is used when performing maintenance on a nozzle unit 161 (see FIG. 3), which will be described later, included in the printing unit 16. The maintenance unit 20 is provided at the Home position of the printer 1 as shown in FIGS. 1 and 3. The printer 1 is provided with a cap, a suction pump, etc. (not shown) for suctioning ink from the nozzles of the nozzle unit 161 after moving the carriage 13 to the Home position at the time of maintenance.

As shown in FIG. 2, the control unit 15 is configured to include an I / F 151, a unit control circuit 152, a memory 153, and a CPU (Central Processing Unit) 154.
The I / F 151 inputs print data input from the external device 30 to the CPU 154.
The unit control circuit 152 includes control circuits for controlling the supply unit 11, the transport unit 12, the carriage movement unit 14, the maintenance unit 20, the printing unit 16, and the spectroscope 17, respectively, based on command signals from the CPU 154. , Control the operation of each unit. The control circuit of each unit may be provided separately from the control unit 15 and connected to the control unit 15.

  The memory 153 stores various programs for controlling the operation of the printer 1 and various data. Examples of the various data include print profile data in which the discharge amount of each ink for color data included as print data is stored. In addition, emission characteristics of each light source 179 to be described later, spectral characteristics depending on the temperature of the spectroscopic device 173A, and the like may be stored.

  The CPU 154 reads out and executes various programs stored in the memory 153 to drive and control the supply unit 11, the transport unit 12, and the carriage moving unit 14, print control of the printing unit 16, measurement control of the spectroscope 17, and Operation processing and correction processing (for example, correction processing of uneven density, correction processing of color misregistration) and the like based on the measurement result of the spectroscope 17 are performed. Specific functions of the CPU 154 will be described later.

[Carriage configuration]
Next, the configurations of the carriage 13, the printing unit 16, the spectroscope 17, and the shutter mechanism 19 provided on the carriage 13 will be described.
As shown in FIG. 3, the carriage 13 is a housing on which the printing unit 16, the spectroscope 17, and the shutter mechanism 19 are mounted, and is moved along the main scanning direction (X direction) by the carriage moving unit 14. Configured to be possible. Among them, the printing unit 16 and the spectroscope 17 are connected to the control unit 15 by the flexible circuit 130 (see FIG. 1), and are driven based on the control signal from the control unit 15.
As will be described in detail later, the shutter 192 provided in the shutter mechanism 19 closes the window 176A (see FIG. 4) of the spectroscope 17 according to the movement of the carriage 13 along the X direction, and the window It is configured to be able to change the state of opening 176 A (the state in which light can be incident on the spectroscope 17).

[Configuration of printing unit]
The printing unit 16 individually discharges the ink onto the medium M on the part facing the medium M based on the command signal from the control unit 15 to form an image on the medium M (the medium M Image formation processing is performed.
As shown in FIG. 3, the printing unit 16 includes a nozzle unit 161 corresponding to a plurality of colors of ink, an ink cartridge (not shown) for supplying ink to each nozzle unit 161, and an ink from the ink cartridge to the nozzle unit 161. And a supply pipe (not shown) for supplying
The nozzle units 161 are provided for each color (for example, cyan, magenta, yellow, light cyan, light magenta, gray, light gray, matte black, photo black, etc.) to be discharged onto the medium M. These nozzle units 161 are provided with nozzles (not shown) for discharging ink droplets. For example, piezo elements are arranged in these nozzles, and by driving the piezo elements, ink droplets supplied from the ink tank are ejected to the + Z side and land on the medium M to form dots.

[Spectroscope configuration]
FIG. 4 is a cross-sectional view showing a schematic configuration of the spectroscope 17. As shown in FIG. FIG. 4 shows the configuration of the spectroscope 17 in a state where the window portion 176A is opened (the shutter 192 is moved to a position (open position) away from the window portion 176A).
The spectroscope 17 includes, as shown in FIG. 4, a base 171, a substrate holding portion 172 fixed to the base 171, and a spectral device holding substrate 173 and a light receiving element holding substrate 174 held by the substrate holding portion 172. , And a cover portion 175.

The base 171 includes a measurement light introducing unit 176 through which light reflected at the measurement position of the medium M passes, and a light source arrangement unit 177 in which the light source 179 is disposed.
The measurement light introducing portion 176 is, for example, a through hole along the Z direction, and the window portion 176A is disposed at the + Z side end. In addition, on the −Z side of the measurement light introducing unit 176, an optical holding unit 178 that holds an incident optical system such as an aperture 178A and an incident lens 178B is fixed. The optical axes of the window portion 176A, the aperture 178A, and the incident lens 178B coincide with the measurement optical axis L of the spectroscopic device 173A described later and the light receiving element 174A.

The light source placement portion 177 has, for example, a cylindrical hole portion 177A that approaches the measurement light axis L as the central axis goes to the + Z side. A light source 179 is disposed on the −Z side of the cylindrical hole portion 177A. The light source 179 may be, for example, an LED, and the LED substrate on which the LED is provided is fixed to the -Z side end of the cylindrical hole portion 177A by screwing or the like, for example. 179) is fixed. A substrate (such as an LED substrate) for holding the light source 179 is connected to a connector 175B described later.
Further, the + Z side end of the cylindrical hole portion 177A becomes an illumination window 177B from which the light of the light source 179 is emitted. When the shutter 192 is in the open position, as shown in FIG. 4, the illumination window 177 B is also opened to face the medium M placed on the platen 122. When the light source 179 emits light in this state, the light of the light source 179 is irradiated to the measurement position P in a predetermined range around the intersection of the medium M and the measurement optical axis L. In the present embodiment, spectrometry is performed in accordance with the (45 ° x: 0 °) system under the optical geometric conditions defined by the colorimetric standard (JIS Z 8722). That is, in the present embodiment, the illumination light from the light source 179 is incident at an incident angle of 45 ° ± 2 ° with respect to the measurement position P, and the light reflected in the normal direction at 0 ° ± 10 ° Enters the light receiving element 174A along the measurement optical axis L.

The substrate holding portion 172 is fixed to the base 171 by, for example, screwing. The spectral device holding substrate 173 and the light receiving element holding substrate 174 are fixed to the substrate holding portion 172.
The spectral device holding substrate 173 is a substrate on which the spectral device 173A is held, and has a through hole on the optical axis (measurement optical axis L) of the spectral device 173A. The spectral device holding substrate 173 is fixed to the substrate holding portion 172 at a position on the −Z side of the optical holding portion 178 and at a position where the optical axis of the spectral device 173A coincides with the measurement optical axis L. The spectroscopic device 173A is an optical device that transmits light of a specific wavelength from incident light, and can exemplify, for example, an etalon element, a liquid crystal tunable filter (LCTF), an acousto-optic variable wavelength filter (AOTF), etc. . The spectral device holding substrate 173 is provided with various circuits for controlling the spectral device 173A, and the circuits are connected to the connector 175B. In addition, the spectral device holding substrate 173 is provided with a temperature measurement unit 173B (see FIG. 2). The temperature measurement unit 173B is a temperature measurement unit according to the present invention, and in the present embodiment, the temperature of the spectroscopic device 173A is measured in the spectrometer 17.

The light receiving element holding substrate 174 is a substrate on which the light receiving element 174A is held. The light receiving element holding substrate 174 is fixed to the substrate holding portion 172 at a position on the −Z side of the spectral device holding substrate 173 and at a position where the optical axis of the light receiving element 174A coincides with the measurement light axis L. In addition, the light receiving element holding substrate 174 includes various circuits for controlling the light receiving element 174A, and the circuits are connected to the connector 175B.
The light receiving element 174A receives the light transmitted through the spectral device 173A in the light receiving area, and outputs a detection signal (current value) according to the amount of light received. The detection signal output from the light receiving element 174A is input to the control unit 15 via an IV converter (not shown), an amplifier (not shown), and an AD converter (not shown).

As shown in FIG. 4, for example, the cover portion 175 is fixed to the outer peripheral edge of the base 171, and together with the base 171, the substrate holding portion 172, the spectral device holding substrate 173, the light receiving element holding substrate 174, and the optical holding portion A closed space (dark space) for accommodating 178 is formed.
Further, an opening 175A is provided in a part of the cover portion 175, and a connector 175B is provided in the opening 175A. The connector 175 B is electrically connected to the control unit 15, and transmits control signals from the control unit 15 to the light source 179, the spectral device holding substrate 173, and the light receiving element holding substrate 174.

[Configuration of shutter mechanism]
FIG. 5 is a cross-sectional view showing a schematic configuration of the carriage 13 provided with the shutter mechanism 19. FIG. 5 shows a state in which the shutter 192 is at the closing position for closing the window portion 176A.
The shutter mechanism 19 shown in the present embodiment is configured of a carriage 13, a shutter holding portion 191 having a shutter 192, and a unit housing 10.
Specifically, as shown in FIG. 5, the bottom 131 of the carriage 13 has an opening for causing the reflected light from the medium M to be incident on the spectroscope 17 at a position overlapping the spectroscope 17 (the window portion 176A) in the Z direction. The part 132 is formed. Further, an insertion hole 134 through which the shutter holding portion 191 is inserted is formed on the side surface 133 on the ± X side of the carriage 13. A surface on the + Z side of the insertion hole 134 is a flat surface parallel to the XY plane, and is flush with the upper surface 131 A (a surface on the −Z side) of the bottom portion 131 of the carriage 13.
Furthermore, a positioning mechanism 135 for positioning the shutter holding portion 191 is disposed in at least one of the ± X-side insertion holes 134 (in the present embodiment, the + X-side insertion holes 134). The positioning mechanism 135 includes, for example, a locking projection provided in the insertion hole 134 or in any one of the shutter holding portions 191, and an engagement hole provided on the other and engaged with the locking projection. It can be illustrated.

  The shutter holding portion 191 is formed in, for example, a flat plate shape elongated in the X direction, as shown in FIG. A shutter 192 is provided on a part of the shutter holding portion 191, and a light passing portion 193 is provided at a position separated by a distance u on the + X side of the shutter 192.

  The shutter 192 is a portion that closes the window portion 176A. The shutter 192 is provided with a reference plate 192A which is a reference object for calculating a correction value of the measurement result of the medium M which is an object. In the present embodiment, the reference plate 192A is a white plate whose reflectance for light of each wavelength in a predetermined wavelength range (for example, visible light range) is, for example, 99% or more, and the shutter 192 is moved to the closing position. , And at a position facing the window portion 176A.

  Further, the shutter 192 is provided with a first wiper 192B in contact with the lower surface of the spectroscope 17 at the end on the + X side. The first wiper 192B contacts the lower surface of the window portion 176A when moving toward the −X side when the shutter 192 moves from the closed position to the open position. Similarly, the first wiper 192B contacts the lower surface of the window 176A also when the shutter 192 moves from the open position to the closed position. Thus, by opening and closing the shutter 192, the window portion 176A can be cleaned by the first wiper 192B.

  Further, on the + Z side surface facing the shutter 192 of the spectroscope 17 (base 171), a second wiper 192C projecting to the + Z side is provided on the −X side of the window portion 176A. The second wiper 192C contacts the reference plate 192A when it moves toward the -X side when the shutter 192 moves from the closed position to the open position, and removes dirt from the surface of the reference plate 192A due to ink droplets and the like. .

  The light passing portion 193 is a portion that allows the reflected light from the measurement position P to pass through the spectroscope 17. The light passing portion 193 may be configured, for example, by a through hole that passes through the shutter holding portion 191 in the Z direction, and a translucent optical member such as a glass plate may be fitted in the through hole. .

The lower surface (the surface on the + Z side) of the shutter holding portion 191 is slidably mounted on the upper surface 131A of the bottom portion 131 of the carriage 13, and both ends thereof are inserted into the insertion holes 134. It is disposed to penetrate in the X direction.
That is, the −X side end (first end 194) of the shutter holding portion 191 protrudes to the −X side through the insertion hole 134 on the −X side of the carriage 13, and the + X side end of the shutter 192 (second The end portion 195) protrudes to the + X side through the insertion hole 134 on the + X side of the carriage 13. Further, the first end portion 194 and the second end portion 195 are formed in a flange shape, whereby the drop of the shutter holding portion 191 from the carriage 13 is suppressed.

In the shutter mechanism 19 having such a configuration, the window portion 176A is opened and closed by the shutter 192 as the carriage 13 moves. Specifically, when the carriage 13 is moved to the end (FULL position) on the + X side, the second end 195 abuts on the second side surface portion 103 of the unit housing 10, and the shutter relative to the carriage 13 The holding unit 191 moves to the −X side by a predetermined distance u (open position). Thereby, the light passing portion 193 faces the window portion 176A, and the reflected light from the measurement position P can be incident on the spectroscope 17.
On the other hand, when the carriage 13 is moved to the end (HOME position) on the -X side, the first end 194 abuts on the first side face 102 of the unit housing 10, as shown in FIG. The shutter holding portion 191 moves to the + X side by a predetermined distance u with respect to 13 (blocked position). Thus, the shutter 192 faces the window portion 176A and is closed by the shutter 192.

[Functional configuration of CPU]
FIG. 6 is a block diagram showing a functional configuration of the CPU 154. As shown in FIG.
The CPU 154 is an operation unit according to the present invention, and reads and executes various programs stored in the memory 153, thereby, as shown in FIG. 6, a scan control unit 154A, a print control unit 154B, a measurement control unit 154C, a correction unit The function 154D functions as a transformation matrix calculation unit 154E, an error determination unit 154F, and a reflectance calculation unit 154G.

  The scan control unit 154 </ b> A outputs, to the unit control circuit 152, a command signal for driving the supply unit 11, the transport unit 12, and the carriage movement unit 14. Thereby, the unit control circuit 152 drives the roll drive motor of the supply unit 11 to supply the medium M to the transport unit 12. Further, the unit control circuit 152 drives the transport motor of the transport unit 12 to transport the predetermined area of the medium M along the Y direction to a position facing the carriage 13 of the platen 122. The unit control circuit 152 also drives the carriage motor 142 of the carriage moving unit 14 to move the carriage 13 along the X direction.

  Further, when changing the position of the shutter 192, the scan control unit 154 </ b> A outputs, to the unit control circuit 152, a command signal to drive the carriage movement unit 14. Thus, the unit control circuit 152 moves the carriage 13 to Home when moving the shutter 192 to the closed position, and moves the carriage 13 to Full when moving the shutter 192 to the open position.

  The print control unit 154B has a unit control circuit for controlling print commands to drive and control the supply unit 11, the transport unit 12, the carriage movement unit 14, and the printing unit 16 based on print data input from the external device 30, for example. Output to 152. The unit control circuit 152 outputs a print control signal to the printing unit 16 and drives a piezo element provided in the nozzle to eject the ink to the medium M.

  The measurement control unit 154C outputs a measurement command signal to drive the spectroscope 17 to the unit control circuit 152, causes the spectroscope 17 to perform measurement processing, and acquires the reflectance of each wavelength with respect to the measurement position P. . Further, the measurement control unit 154C drives the spectroscope 17 to perform measurement processing of the reference plate 192A and the medium M. The specific measurement method will be described later.

The correction unit 154D performs various correction processes based on the reflectance for each wavelength of the medium M obtained by the spectroscope 17. Examples of the correction processing include correction of uneven density and color misregistration.
The transformation matrix calculation unit 154E performs calculation processing of a transformation matrix Ms described later. The specific calculation method will be described later.
The error determination unit 154F performs an error determination process based on the measurement result of the reference plate 192A.
The reflectance calculation unit 154G performs processing to calculate the reflectance for each wavelength of the medium M. The specific calculation method will be described later.

[Spectrometry and transformation matrix calculation processing]
Next, calculation processing of the transformation matrix Ms for calculating the reflectance of the object in the printer 1 of the present embodiment will be described based on the drawings.
FIG. 7 is a flowchart showing an example of conversion matrix calculation processing in the printer 1.
In the printer 1 of the present embodiment, illumination light is emitted from the spectrometer 17 to the medium M by control of the measurement control unit 154C, and light reflected by the medium M is split into light of a plurality of wavelengths by the spectral device 173A. The light of each wavelength that has been dispersed is received by the light receiving element 174A. As a result, a detection signal corresponding to the amount of light received by the light receiving element 174A is input from the spectroscope 17 to the control unit 15 as a measurement result. The measurement results include measurement values (voltage values) for a plurality of wavelengths (for example, wavelengths of 16 bands at 20 nm intervals from 400 nm to 700 nm) when the medium M is measured. Then, the reflectance calculation unit 154G causes the conversion matrix to act on the measurement values for each wavelength included in the measurement result, and directly calculates the reflectance for each wavelength of the medium M.

  Such a conversion matrix needs to be set in accordance with the characteristics of the individual spectroscopes 17, and thus, for example, at the time of manufacturing the printer 1, the spectroscopes 17 are measured in advance and stored in the memory 153. In addition to this, in the present embodiment, the CPU 154 functions as the conversion matrix calculation unit 154E to calculate the conversion matrix even if aging occurs in the light source 179 or the spectral device 173A after the printer 1 is shipped, The transformation matrix stored in the memory 153 can be updated. When the conversion matrix is updated by the printer 1, for example, when a predetermined period has elapsed since the start of use of the printer 1, a guidance message is output to, for example, a display (not shown) etc. Prompt the update process. Then, when the user inputs an operation indicating that the update process is to be performed, the process of calculating the transformation matrix as shown in FIG. 7 is started.

The calculation process of the transformation matrix is performed in a state where the sample Z is disposed on the upper surface of the platen 122, that is, the position where the medium M is disposed. For sample Z, it is preferable to use, for example, a ceramic tile with little deterioration in color such as fading, and n (n is a natural number) (for example, 50 colors) in which RGB gradation values are shifted at substantially equal intervals. Pattern image (color patch) is formed.
In the present embodiment, in each of the color patches formed on the sample Z, the reflectance (for example, 400 nm to 700 nm) at 10 nm intervals for k (k is a natural number) wavelengths in the target wavelength range that can be measured by the spectrometer 17 The reflectance of each of the 31 bands is known, and the reflection spectrum of each color is stored in the memory 153 as a matrix _{Sn, k} . For example, in the present embodiment, color patches of 50 colors are formed on the sample Z, the reflectance of 31 bands for each color is known, and the reflection spectrum of each color is stored in the memory 153 as the matrix _S50,31 .

When the user issues a command to calculate a conversion matrix, first, the scan control unit 154A moves the carriage 13 to FULL and moves the shutter 192 to the open position (step S1).
Thereafter, the measurement control unit 154C drives the spectroscope 17 to execute a sample measurement process of performing the spectral measurement of the sample Z (step S2).
In the sample measurement process, the measurement control unit 154C controls the spectral device 173A and the light receiving element 174A to process m (m is a natural number) wavelengths (for example, natural numbers) in the target wavelength range for each color of the color patch formed on the sample Z Measure the measured values for the wavelengths of 16 bands (at intervals of 20 nm in the visible light range from 400 nm to 700 nm). In the present embodiment, when light is received by the light receiving element 174A, a detection signal of current corresponding to the amount of received light is output from the light receiving element 174A, and the IV converter of the light receiving element holding substrate 174, amplifier, and AD conversion The signal is processed by the controller and input to the control unit 15 as a digital signal indicating a voltage value. Then, measured values corresponding to the detection signal are stored in the memory 153 as a matrix D _{n, m} . That is, in the present embodiment, the measured values are stored in the memory 153 as the matrices D _{50 and 16} . In step S2, the number (m) of measurement bands in the target wavelength region may be the same as the number (k) of measurement bands of the reflection spectrum of the sample Z.

After step S2, the transformation matrix calculation unit 154E performs transformation matrix operation processing using the reflectance matrix S _{n, k} and the measurement value matrix D _{n, m} stored in the memory 153 (step S3). ).
Here, the transformation matrix Ms can be expressed as the following equation (1) from the matrix S _{n, k} and the matrix D _{n, m} .

S _{n, k} ^T = Ms · D _{n, m} ^T (1)

In the above equation (1), T displayed on the right shoulder of the reflectance matrix S _{n, k} and the measurement value matrix D _{n, m} indicates that it is a transposed matrix.
Here, if a correct conversion matrix Ms is obtained, Ms · D _{n, m} ^T should match S _{n, m} ^T. Therefore, an evaluation function F (Ms) representing the deviation between S _{n, k} ^T and Ms · D _{n, m} ^T is set as in the following equation (2), and this evaluation function F (Ms) is minimized The transformation matrix Ms can be determined by expanding into.

F (Ms) = | Sn _{, k} -Ms D _{n, m} | ² (2)

  Then, the solution that makes the above equation (2) the minimum is a solution in which the value obtained by partially differentiating the evaluation function F (Ms) by Ms is 0, as in the case of the least square error solution. That is, the equation (2) can be expanded to obtain the following equation (3).

−2 (D _{n, m} ^T · D _{n, m} ) · Ms + 2 D _{n, m} ^T · S _{n, k} = 0
(D _{n, m} ^T · D _{n, m} ) · Ms = D _{n, m} ^T · S _{n, k}
Ms = (D _{n, m} ^T · D _{n, m} ) ⁻¹ · D _{n, m} ^T · S _{n, k} (3)

In step S3, the conversion matrix calculation unit 154E calculates the conversion matrix Ms using the matrix S _{n, k} and the matrix D _{n, m} by expanding as shown in the equation (3).

  Referring back to FIG. 7, when the transformation matrix Ms is calculated in step S3, the transformation matrix calculation unit 154E stores the calculated transformation matrix Ms in the memory 153 (step S4).

Correction processing
Next, color misregistration correction processing will be described based on the drawings as an example of the correction processing in the printer 1 of the present embodiment.
FIG. 8 is a flowchart showing an example of the correction process in the printer 1.
The correction process by the printer 1 is performed, for example, when the power is turned on or when an instruction to execute the correction process is received.

In the spectrometry method shown in FIG. 8, first, the scan control unit 154A moves the carriage 13 to the HOME and moves the shutter 192 to the closed position (Step S10).
Thereafter, the print control unit 154B prints a pattern image for color misregistration correction on the medium M (step S20). The color misregistration correction pattern image can be exemplified by, for example, a color chart in which a plurality of color patches having different colors are arranged along the X direction and the Y direction. The color patch used here may be a color patch of the same color as that of the conversion matrix.
At this time, since the shutter 192 is located at the closed position, the intrusion of foreign matter such as ink mist into the spectroscope 17 during printing is suppressed.

After step S20, the measurement control unit 154C drives the spectroscope 17 to perform a reference plate measurement process of spectroscopically measuring the reference plate 192A as a reference object (step S30).
FIG. 9 is a flowchart showing reference plate measurement processing.
In the reference plate measurement process of step S30, as shown in FIG. 9, the measurement control unit 154C performs measurement of measurement values for light of m wavelengths in the target wavelength range and measurement of temperature by the temperature measurement unit 173B. (Step S31). The measurement of the measurement value in step S31 is the same process as the sample measurement process in step S2, and the measurement value for the same wavelength as each wavelength measured in step S2 is acquired. For example, the measurement control unit 154C measures, for example, measured values of 16 bands at intervals of 20 nm from 400 nm to 700 nm.

  Next, as shown in FIG. 9, the error determination unit 154F calculates the correlation coefficient between the initial value of the measured value for each measured wavelength at the time of factory shipment stored in the memory 153 and the measured value measured in step S31. The R and the inclination α are calculated (step S32).

Next, the error determination unit 154F determines whether the correlation coefficient R is equal to or greater than a predetermined reference value H (step S33). The reference value H is the lower limit value of the correlation coefficient R stored in advance in the memory 153, and can be appropriately set according to the tolerance of the result of the spectroscopic measurement related to the correction process, for example, 0.9 The value of the degree is set.
FIG. 11 is a view showing an example of the correlation between the initial value of the measured value and the measured value measured in step S31. In the example of FIG. 11, the horizontal axis represents the measurement value (initial value) of the wavelength of 16 bands at an interval of 20 nm from 400 nm to 700 nm at factory shipment (initial value), and the vertical axis is the measurement value of the same wavelength measured in step S31. It is an example which shows the correlation at the time of making the measured value of the amount of light reception of each band corresponding to the initial value, and plotting.
When the window 176A is not soiled and the reference plate 192A is not soiled, the measured value does not change so much, so the variation of the measured value measured in step S31 with respect to the initial value becomes smaller and the correlation coefficient R becomes larger.
On the other hand, if dirt such as ink mist adheres to the window portion 176A or the reference plate 192A, the measured value of the amount of received light fluctuates. Therefore, as shown in FIG. Variations in the measured values measured by That is, the correlation coefficient R between the initial value and the measured value decreases. Therefore, by determining whether or not the correlation coefficient R is equal to or greater than the reference value H in step S33, it is possible to detect dirt on the window portion 176A and the reference plate 192A.

  When it is determined No in this step S33 (in the case of R <H), the scan control unit 154A moves the carriage 13 to the FULL position and opens and closes the shutter 192 to open the window portion 176A and the wipers 192B and 192C. The reference plate 192A is cleaned (step S331). When cleaning of the window portion 176A is completed, the error determination unit 154F adds 1 to the variable “j” (initial value: 0) indicating the number of cleanings (step S332), and determines whether j ≧ N (step S333).

If the error determination unit 154F determines NO in step S333, the error determination unit 154F returns to step S31 and performs again the spectroscopic measurement of the reference plate 192A.
If YES is determined in the step S333, there is a possibility that there is a dirt that can not be removed by the cleaning with the wipers 192B and 192C, or an accurate spectral measurement may not be performed due to other factors. In this case, the error determination unit 154F outputs an error (step S334). For example, the error determination unit 154F displays an error message on a display (not shown) or the like to urge the user to perform maintenance.
In addition, as the predetermined number N of repeating the spectral measurement and the cleaning, the number of times of about three times is usually set.

On the other hand, when the determination in step S33 is YES, the error determination unit 154F determines whether the slope α is equal to or larger than the threshold K (step S34). The threshold value K is a lower limit value of the inclination α stored in advance in the memory 153, and for example, a value of about 0.7 is set.
FIG. 12 is a diagram showing an example of the slope of the measured value with respect to the initial value when plotting the measured value of the light reception amount of each band in correspondence with the initial value, as in FIG.
When the light source is not deteriorated, the light reception amount of each measurement wavelength measured in step S31 shows a value close to the initial value, so the inclination α of the measured value with respect to the initial value becomes a value close to “1”.
On the other hand, when the light amount decreases due to the deterioration of the light source 179 or the like, the light reception amount with respect to each measurement wavelength decreases uniformly. Then, as shown in FIG. 12, the inclination α of the measurement value with respect to the initial value decreases. Therefore, by determining whether or not the inclination α is equal to or larger than the threshold value K in step S34, it is possible to detect that the light amount is decreased due to the deterioration of the light source 179 or the like.

  If it is determined NO in this step S34 (α <K), the light source 179 may be deteriorated. In this case, the error determination unit 154F displays an error message on a display (not shown) or the like to prompt the user to perform maintenance (step S341).

  If it is determined as YES in step S34, the measurement control unit 154C stores the inclination α and the temperature measurement value T in the memory 153 (step S35), and ends the reference plate measurement process.

Returning to FIG. 8, when the reference plate measurement process is completed, the scan control unit 154A moves the carriage 13 to FULL and moves the shutter 192 to the open position (step S40). Then, the control unit 15 executes a pattern image measurement process (step S50).
In the pattern image measurement process, the scan control unit 154A moves the carriage 13 and the medium M to sequentially position the measurement area of the spectroscope 17 on the color patch. Then, the measurement control unit 154C performs spectrometry on each color patch. This spectral measurement is performed in the same manner as the reference plate measurement process shown in FIG. 9, and the measured value D ′ for each measurement wavelength is stored in the memory 153.

Then, when the measurement for all color patches is completed, the reflectance calculation unit 154G uses the conversion matrix Ms, the inclination α, the temperature measurement value T, and the measurement value D ′ stored in the memory 153 to determine the medium M as an object. A reflectance calculation process is performed to calculate the reflectance of (step S60).
FIG. 10 is a flowchart showing the reflectance calculation process.
In the reflectance calculation process of step S60, as shown in FIG. 10, the reflectance calculation unit 154G corrects the measured value D ′ based on the inclination α and the measured temperature value T (step S61). Here, for the correction of the measured value D ′, either the correction by the inclination α or the correction by the temperature measured value T may be performed first. In addition, for this correction, a correction table corresponding to the inclination α and the temperature measurement value T may be stored in advance in the memory 153 or a correction value may be calculated according to the inclination α and the temperature measurement value T. It is also good.
In the present embodiment, by correcting the measurement value D ′ based on the measurement result of the substrate measurement process and the temperature measurement result as described above, it is possible to eliminate the influence of light source deterioration or temperature drift of a spectroscopic device or the like. Hereinafter, the measurement value D ′ after correction is taken as a correction measurement value D.

After that, the reflectance calculation unit 154G calculates the reflectance of the medium M, which is the object, by multiplying the correction measurement value D by the conversion matrix Ms, as shown in equation (1) (step S62). That is, by causing the conversion matrix Ms to act on the measured values measured by the spectroscope 17, it is possible to directly calculate the reflectance of the medium M as the object without obtaining the reflectance of the reference plate 192A.
Then, the reflectance calculation unit 154G stores the calculated reflectance in the memory 153 (step S63), and ends the reflectance calculation process.

Referring back to FIG. 8, the correction unit 154D compares the reflectance calculated in the reflectance calculation process with the reference reflectance stored in advance in the memory 153 to obtain a colorimetric result (for example, an XYZ value, L * a *, etc.). b * value etc) is calculated (step S70). Then, the correction unit 154D performs color misregistration correction processing based on the color measurement result obtained in step S70 (step S80).
After the color misregistration correction processing is performed, a color patch is newly printed, the printing unit prints the color patch on the medium M, and the spectroscope performs a spectroscopic measurement to obtain a measurement result, and the conversion stored in the memory 153 Calculate the reflectance of the color patch using a matrix. If the desired reflectance is not obtained, color patch printing and spectrometry are further repeated so that the amount of color misregistration of the color patch to be printed is within an acceptable range.
As described above, since the conversion matrix stored in the memory 153 is used in calculating the reflectance of the color patch, the reflectance can be calculated without measuring the reflectance of the reference object.

[Operation and effect of the first embodiment]
The printer 1 according to the present embodiment includes a spectroscope 17 that measures the amount of light for a plurality of wavelengths of light from the medium M, which is an object, and an arithmetic unit that calculates the reflectance of the medium M based on the measurement results by the spectroscope 17. The CPU 154 operates the conversion matrix Ms that converts the measured value to the reflectance on the measured value measured by the spectroscope 17 to calculate the reflectance of the medium M.

  In such a configuration, the CPU 154 can directly calculate the reflectance of the medium M from the measurement value (voltage value) measured by the spectroscope 17. Therefore, when calculating the reflectance of the medium M, it is not necessary to measure the reflectance of the reference color using the reference plate 192A, which is a reference object, and the condition at the time of color measurement is measured by the reference plate 192A and the medium M. There is no need to align. Therefore, it is not necessary to arrange the reference plate 192A at the same height as the medium M, and the degree of freedom in the arrangement of the reference plate 192A can be increased.

In this embodiment, the conversion matrix Ms uses the reflectance for k wavelengths of the sample Z whose reflectance is known and the measured values for m wavelengths when the sample Z is measured by the spectroscope 17. It is calculated.
Therefore, if the sample Z whose reflectance is known is prepared, it is possible to calculate the transformation matrix Ms without using a special device. Therefore, it is possible to easily calculate the transformation matrix Ms for directly calculating the reflectance from the measurement value measured by the spectroscope 17.

In this embodiment, _{assuming that} the evaluation function F (Ms) is F (Ms) = | S _{n, k} −Ms · D _{n, m} | ² , the transformation matrix Ms is a matrix that minimizes the evaluation function F (Ms). is there.
Therefore, the transformation matrix Ms can be determined by expanding the evaluation function F (Ms) in the same manner as a general least squares error solution. Therefore, it is possible to easily determine the transformation matrix Ms for directly calculating the reflectance from the measurement value measured by the spectroscope 17.

In the present embodiment, the CPU 154 uses a matrix D _{n, m} of measurement values when the sample Z is measured by the spectroscope 17 and a matrix S _{n, k} of known reflectance of the sample Z, and converts the transformation matrix M s calculate.
For this reason, if the sample Z whose reflectance is known is prepared, it is possible to calculate the transformation matrix Ms for directly calculating the reflectance from the measurement value measured by the spectroscope 17. Therefore, for example, when the light source 179 or the like changes with time due to the printer 1 being used for a long time, the conversion matrix Ms in that state can be calculated, and the reflectance of the medium M can be calculated accurately.

In the present embodiment, the printer 1 includes the reference plate 192A, which is a reference object, and the CPU 154 performs spectroscopy based on the measurement result of the reference plate 192A by the spectroscope 17 when the light from the light source 179 is irradiated to the reference plate 192A. The measured value D ′ when the medium M is measured by the unit 17 is corrected.
Therefore, for example, even if the light quantity of the light source 179 of the spectroscope 17 is changed, the measured value which is the measurement result of the medium M based on the measurement result of the reference plate 192A measured in the state where the light quantity of the light source 179 is changed. Since D 'is corrected, the influence can be eliminated. Therefore, the reflectance of the medium M can be accurately calculated.

In the present embodiment, the printer 1 includes the temperature measurement unit 173B that measures the temperature of the spectrometer 17. The CPU 154 measures the medium M by the spectrometer 17 based on the temperature measurement value T measured by the temperature measurement unit 173B. Correct the measured value D 'at the time of
Therefore, for example, even if the characteristic of the spectroscopic device 173A changes due to a temperature change, if the relationship between the characteristic of the spectroscopic device 173A and the temperature is obtained in advance, the change of the characteristic is grasped by the measured temperature value T can do. Therefore, the measured value D 'correction can be performed according to the change of the characteristic, and the reflectance of the object can be accurately calculated.

Second Embodiment
Next, a second embodiment will be described.
In the first embodiment, as shown in the equation (2), the transformation matrix Ms is determined by expanding the evaluation function F (Ms) = | S _{n, k} −Ms · D _{n, m} | ² In the second embodiment, the equation for determining the transformation matrix Ms is different from the first embodiment.

In the above equation (2), under the condition that no error is included in the matrix S _{n, k} or the matrix D _{n, m} , a conversion matrix M s capable of calculating the reflectance as the best linear unbiased estimator It is possible to calculate. However, if an error is included in the matrix S _{n, m} or in the matrix D _{n, m} , it becomes a parameter of the overfitting state depending on the degree. In this case, the parameters of the transformation matrix Ms determined by expanding this evaluation function F (Ms) will be obtained as a mixture of very large values and small values, and the variation of the parameters will be large. . In this case, when the conversion matrix is applied to the measurement value of the measurement result by the spectroscope 17 to calculate the reflectance, the measurement value of the measurement result is a measurement value including an error similar to that at the calculation of the conversion matrix. Although the reflectance can be determined with high accuracy, the estimation accuracy of the reflectance is lowered (over-fitting) depending on the degree of the error included in the measurement value of the measurement result and the variation. In order to suppress this overfitting, it is necessary to add a constraint that reduces the variation in parameters. Therefore, the above equation (2) is replaced as follows using Lagrange's undetermined multiplier method.

F (Ms) = | Sn _{, k} -Ms D _{n, m} | ² + β Ms ^T Ms (4)

In the above equation (4), β is a constant called a hyper parameter. In the above equation (4), it is added βMs ^T Ms is number term to multiply the evaluation function F (Ms). Therefore, a constraint term that minimizes the variance (or Euclidean norm) of the parameters of the conversion matrix Ms is added to the evaluation function F (Ms), and regularization can be performed. This makes it possible to reduce variations in the parameters of the conversion matrix Ms, and to calculate a conversion matrix that can suppress overfitting. That is, when the measured value of the measurement result is converted to the reflectance using the conversion matrix Ms, the reflectance can be calculated with high accuracy even if there is a variation in the error included in the measured value.

[Modification]
Note that the present invention is not limited to the above-described embodiment, and modifications, improvements, and the like as long as the object of the present invention can be achieved are included in the present invention.

  In each of the above embodiments, the measurement value is an example of a digital signal indicating a voltage value, which is signal-processed by the I-V converter, the amplifier, and the AD converter of the light receiving element holding substrate 174. Absent. For example, the current value (current spectrum) for each wavelength may be acquired as a measurement value by sampling the detection signal (current value) output from the light receiving element 174A at the timing when the spectral wavelength is switched by the spectroscopic device 173A. . In this case, a matrix that converts current values to reflectance is used as the conversion matrix Ms.

  In each of the above embodiments, the reference plate 192A, which is a reference object, is a white plate having a reflectance of 99% or more to light of each wavelength in a predetermined wavelength range (for example, visible light range). Absent. The reference color of the reference plate 192A is not limited to white, and may be any color as long as it can set the standard for performing the measurement. In this case, the reflectance of the reference color is preferably known, but is not limited thereto. That is, when the light of the light source is irradiated to the reference plate, the initial value of the detection signal output from the light receiving element may be stored in the memory.

  In the above embodiments, the reference plate 192A is provided at a position facing the window portion 176A of the shutter 192. However, the present invention is not limited to this. For example, the reference plate 192A may be provided on the upper surface of the platen 122, as long as it can be measured by the spectroscope 17. Further, instead of the reference plate, the shutter 192 itself, a columnar material or the like may be used as a reference object.

In each of the above-described embodiments, although an example in which the conversion matrix Ms is calculated when a predetermined period has elapsed since the start of use of the printer 1 is shown, the present invention is not limited thereto. For example, in the printer 1, the conversion matrix Ms may not be calculated, but may be measured in advance at the time of manufacture of the printer 1 and stored in the memory 153 for use in the reflectance calculation process of the medium M. In this case, since the conversion matrix calculation process is not performed in the printer 1, the conversion matrix calculation unit 154E may not be provided.
In addition, the conversion matrix Ms calculated in the above embodiment is stored in memory 153 in place of the conversion matrix measured in advance at the time of manufacture, and stored for regular use in the reflectance calculation processing of medium M. May be Also, the transformation matrix Ms may be calculated and updated as necessary.

  In each of the above embodiments, the temperature measurement unit 173B is provided on the spectral device holding substrate 173, but the present invention is not limited to this. For example, the temperature measuring unit may be provided on the light receiving element holding substrate 174, as long as the temperature of the spectroscope 17 can be measured. Further, a plurality of temperature measurement units may be provided.

  In each of the above embodiments, an example in which the temperature measurement unit 173B measures the temperature in the reference plate measurement process of step S30 is described, but the present invention is not limited thereto. For example, the temperature measurement by the temperature measurement unit 173B may be performed in the pattern image measurement process of step S50, as long as the temperature measurement is performed in the correction process.

In each of the above embodiments, an example in which the shutter 192 can be moved in the X direction with respect to the carriage 13 by the movement of the shutter holding portion 191 is shown, but the present invention is not limited thereto. For example, the shutter 192 may be provided so as to be rotatable around a rotation axis parallel to the Z direction, and may be movable between the closed position and the open position by rotating around the rotation axis.
In addition, the shutter 192 is moved by moving the carriage 13 and bringing the first end 194 and the second end 195 into contact with the unit housing 10, but for example, a driving source such as a motor is used as the carriage 13. It may be mounted, and the shutter 192 may be moved by the driving force from the drive source.

  In each of the above-described embodiments, an example in which the printer 1 is a so-called inkjet printer including the printing unit 16 that discharges ink to form an image is shown, but the invention is not limited thereto. The configurations of the above-described embodiments can be applied to a printer including a printing unit that forms an image. As such a printer, for example, a so-called thermal transfer printer which heats and melts an ink ribbon as an image forming material and transfers it to the medium M, a latent image is developed using toner, and the developed image is used as a medium There are so-called electrophotographic printers that transfer to M.

  Moreover, although the printer 1 was shown as an electronic device, it does not restrict to this. For example, it may be a measuring device that does not include the printing unit 16 and performs only the measurement of the medium M. For example, the spectral measurement device of the present invention may be incorporated into a quality inspection device that performs quality inspection of printed matter manufactured in a factory or the like, and the spectral measurement device of the present invention may be incorporated into any other electronic device.

  In addition, the specific structure at the time of implementation of this invention can be suitably changed into another structure etc. in the range which can achieve the objective of this invention.

  DESCRIPTION OF SYMBOLS 1 ... Printer (electronic device), 10 ... Unit housing | casing, 13 ... Carriage, 15 ... Control unit (control part), 17 ... Spectroscope, 153 ... Memory, 154 ... CPU (calculation part), 154D ... Correction part, 154E ... transformation matrix calculation unit, 154F ... error determination unit, 154G ... reflectance operation unit, 192 ... shutter, 192A ... reference plate (reference object), M ... media (object), Z ... sample.

Claims (9)

A spectrometer that measures the amount of light for multiple wavelengths of light from the object;
And a calculation unit that calculates the reflectance of the object based on the measurement results of the light amounts for the plurality of wavelengths,
The spectrometer according to claim 1, wherein the calculation unit calculates a reflectance of the object by causing a conversion matrix that converts the measurement result to a reflectance to act on the measurement result. In the spectrometer according to claim 1,
The conversion matrix is a reflectance for k (k is a natural number) wavelengths of a sample whose reflectance is known, and a measurement result for m (m is a natural number) wavelengths when the sample is measured by the spectrometer. It is a matrix calculated using and, The spectrometry apparatus characterized by the above-mentioned. In the spectrometer according to claim 2,
Let S _{n, k} be a matrix of known reflectances for the k wavelengths in each of n (n is a natural number) of the samples having different colors.
Let D _{n, m} be a matrix of light intensity measurement results for the m wavelengths in each of the n samples.
Let the transformation matrix be Ms,
Evaluation function F _{(Ms) F (Ms) =} | S n, k -Ms · D n, m | a ^2,
The said transformation matrix Ms is a matrix which the said evaluation function F (Ms) becomes the minimum. The spectroscopy measurement apparatus characterized by the above-mentioned. In the spectrometer according to claim 2,
Let S _{n, k} be a matrix of known reflectances for the k wavelengths in each of n (n is a natural number) of the samples having different colors.
Let D _{n, m} be a matrix of light intensity measurement results for the m wavelengths in each of the n samples measured by the spectrometer.
Let the transformation matrix be Ms and the constant be β,
Let the evaluation function F (Ms) be F (Ms) = | S _{n, k} −Ms · D _{n, m} | ² + β · Ms ^T · Ms
The said transformation matrix Ms is a matrix which the said evaluation function F (Ms) becomes the minimum. The spectroscopy measurement apparatus characterized by the above-mentioned. The spectrometer according to any one of claims 1 to 4, wherein
The calculation unit uses measurement results for m (m is a natural number) wavelengths when measuring a sample whose reflectance is known and k (k is a natural number) reflectances of the sample. Calculating the transformation matrix. The spectrometer according to any one of claims 1 to 5,
Further equipped with a reference
The said calculation part correct | amends the measurement result at the time of measuring the said target object based on the measurement result with respect to the said reference object at the time of irradiating the light from a light source to the said reference object. The spectrometer according to any one of claims 1 to 6,
It further comprises a temperature measurement unit that measures the temperature of the spectrometer.
The said calculating part correct | amends the measurement result at the time of measuring the said target object based on the temperature measured by the said temperature measurement part. The spectrometry device according to any one of claims 1 to 7,
A control unit that controls the calculation unit;
An electronic device comprising: The spectrometer measures the amount of light for multiple wavelengths of light from the object,
A reflectance measurement method comprising: calculating a reflectance of the object by causing a calculation matrix to act on the measurement result to convert the measurement result of the light quantity for the plurality of wavelengths into the reflectance.

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