JP2018149702A - Optical sensor module and image formation device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical sensor module capable of detecting each color image with high resolution, and an image formation device.SOLUTION: An optical sensor module comprises: a light source; and an imaging part receiving reflection light reflected on a measuring object being irradiated with from the light source and formed on a medium. The imaging part has an R detection element, a B detection element and a G detection element corresponding to each color of red, blue and green. The light source comprises: a white light source emitting white light; and an auxiliary light source emitting auxiliary light. The auxiliary light is light of a wave length corresponding to a peak value when multiplying a difference between a reflectance of the medium and a reflectance of the measuring object by detection sensitivity in the R detection element or the G detection element in each wave length.SELECTED DRAWING: Figure 3

Description

  The present invention relates to an optical sensor module and an image forming apparatus.

Conventionally, a test pattern is printed on a medium such as a paper surface, light from a light source unit is irradiated onto the test pattern, and an image is picked up by an imaging device. Based on the obtained captured image, for example, a print correction such as color unevenness correction There is known a printer that performs (see, for example, Patent Document 1).
In the apparatus described in Patent Document 1, the light of a light source having a complementary color relationship with the color of the test pattern is irradiated on the medium, and abnormal ink ejection is detected based on the captured image.

JP 2013-240913 A

By the way, in the apparatus described in Patent Document 1, it is necessary to select a light source having a complementary color according to the color of each ink, and the circuit configuration for controlling the turning on and off of the light source becomes complicated. On the other hand, a circuit configuration can be simplified by using a white light source as the light source and detecting an ink ejection abnormality by capturing a captured image with an RGB camera. Even in this case, the complementary color can be detected in any of the RGB color pixels of the captured image captured by the RGB camera.
However, when a white light source is used, a complementary color may be detected only with any one of RGB. That is, in a general ink jet printer, ink of 10 colors is used, but in many cases, the color of ink can be detected by two or more color pixels (for example, R and G, G and B, etc.). However, since the yellow color can be detected only by the B element, the resolution of the yellow captured image using the RGB camera is lower than the resolution of the captured image of other colors.

  An object of the present invention is to provide an optical sensor module and an image forming apparatus capable of detecting each color image with high resolution.

  An optical sensor module of an application example according to the present invention includes a light source, and an imaging unit that receives reflected light reflected from a measurement target that is irradiated from the light source and formed on a medium, and the imaging unit Has an R detection element, a B detection element, and a G detection element corresponding to each color of red, blue, and green, and the light source includes a white light source that emits white light, an auxiliary light source that emits auxiliary light, and The auxiliary light corresponds to a peak value when the difference between the reflectance of the medium and the reflectance of the measurement target and the detection sensitivity of the R detection element or the G detection element are multiplied at each wavelength. It is characterized by being light of a wavelength.

  In this application example, from the auxiliary light source, the difference between the reflectance of the medium and the reflectance of the measurement target and the detection sensitivity of the R detection element or G detection element correspond to the peak value when multiplied for each wavelength. Auxiliary light having a wavelength to be irradiated is irradiated on the measurement object. When a white LED is used as the white light source, if a yellow image is formed on the measurement target, the yellow can be detected with high detection accuracy only by the B detection element. On the other hand, by using the auxiliary light as described above, a yellow image can be detected with high accuracy even in the R detection element or the G detection element. That is, a yellow image can be detected by the two detection elements of the B detection element and either the R detection element or the G detection element, and the resolution of the yellow image can be improved. Therefore, in this application example, each color image can be detected with high resolution.

In the optical sensor module according to this application example, it is preferable that the measurement target is a yellow image, and the auxiliary light is light having a wavelength of 500 to 510 nm.
As described above, in this application example, as the auxiliary light, light having a wavelength corresponding to the peak value when the difference between the reflectance of the medium and the reflectance of the measurement target is multiplied by the detection sensitivity of the R detection element, or Then, light having a wavelength corresponding to the peak value obtained by multiplying the difference between the reflectance of the medium and the reflectance of the measurement object and the detection sensitivity of the G detection element is used. Here, when the measurement object is a yellow image, the peak value when the difference between the reflectance of the medium and the reflectance of the measurement object and the detection sensitivity of the G detection element is multiplied is the reflectance of the medium and the measurement object. The peak value obtained by multiplying the difference from the reflectance by the detection sensitivity of the R detection element is at least twice as large. Therefore, by using the light of the wavelength corresponding to the peak value when multiplying the difference between the reflectance of the medium and the reflectance of the measurement object and the detection sensitivity of the G detection element as auxiliary light, The amount of auxiliary light can be reduced as compared with the case where light having a wavelength corresponding to the peak value obtained by multiplying the difference between the reflectance of the measurement object and the detection sensitivity of the R detection element is auxiliary light.
Here, the light having a wavelength of 500 to 510 nm used in this application example represents the difference between the reflectance of the medium and the reflectance of the yellow image to be measured and the detection sensitivity of the G detection element at each wavelength. It is the light having the wavelength that becomes the peak value when multiplied. Therefore, the amount of auxiliary light can be reduced by using light having a wavelength of 500 to 510 nm as auxiliary light.

  An optical sensor module according to an application example of the present invention includes a light source, and an imaging unit that receives reflected light reflected from a measurement target that is irradiated from the light source and formed on a medium. Has an R detection element, a B detection element, and a G detection element corresponding to each color of red, blue, and green, and the light source includes a white light source that emits white light, an auxiliary light source that emits auxiliary light, and The auxiliary light is calculated by calculating a first value obtained by multiplying the difference between the reflectance of the medium and the reflectance of the measurement object and the detection sensitivity of the R detection element or the G detection element at each wavelength. Further, the present invention is characterized in that the light has a wavelength at which the ratio of the first value to the R detection element and the first value to the G detection element is 0.9 or more and 1.1 or less.

In this application example, when the first value obtained by multiplying the difference between the reflectance of the medium and the reflectance of the measurement object and the detection sensitivity of the R detection element or the G detection element at each wavelength is calculated from the auxiliary light source. The measurement object is irradiated with auxiliary light having a wavelength at which the ratio of the first value for the R detection element and the first value for the G detection element is 0.9 or more and 1.1 or less. That is, light having a wavelength at which the first value for the R detection element and the first value for the G detection element are the same or substantially the same is used as auxiliary light.
In this case, the detection sensitivity for a yellow image can be increased by both the R detection element and the G detection element. Therefore, a yellow image can be detected by the three detection elements of the B detection element, the R detection element, and the G detection element, and the resolution of the yellow image can be improved.

An image forming apparatus according to an application example of the invention includes the above-described optical sensor module and an image forming unit that forms an image on the medium.
In this application example, it is possible to inspect whether or not an appropriate image is formed by the image forming unit by forming an image on the medium by the image forming unit and measuring the formed image by the optical sensor module. If an appropriate image is not formed, correction (printing correction) can be performed based on the measurement result so that the image forming process by the image forming unit is appropriately performed. At this time, by using the optical sensor module as described above, each color including yellow can be detected with high accuracy with a simple configuration using an imaging unit, a white light source, and an auxiliary light source, and each color image can be enhanced. It is possible to obtain with resolution. Therefore, printing correction in the image forming unit can be performed with high accuracy.

FIG. 3 is a diagram illustrating a configuration example of an appearance of the printer (image forming apparatus) according to the first embodiment. 1 is a block diagram illustrating a schematic configuration of a printer according to a first embodiment. The figure which shows schematic structure of the imaging part of 1st embodiment. The figure which shows an example of the image pick-up element of 1st embodiment. The figure which shows the reflectance difference detection amount at the time of using only a white light source. The difference between the reflectance of each wavelength of the medium and the reflectance of each wavelength of the yellow test pattern and the detection sensitivity of each wavelength of the R detection element, and the reflectance of each wavelength of the medium and the yellow test The figure which shows the value which multiplied the difference with the reflectance of each wavelength of a pattern, and the detection sensitivity of each wavelength of G detection element. The figure which shows the reflectance difference detection amount at the time of using a white light source and an auxiliary light source in 1st embodiment. The figure which shows the reflectance difference detection amount at the time of using a white light source and an auxiliary light source in 2nd embodiment. The figure which shows the reflectance difference detection amount at the time of using a white light source and an auxiliary light source in 2nd embodiment.

[First embodiment]
Hereinafter, a first embodiment according to the present invention will be described. In the present embodiment, a printer (inkjet printer) will be described below as an example of the image forming apparatus of the present invention.

[Schematic configuration of printer]
FIG. 1 is a diagram illustrating a configuration example of an appearance of a printer 1 according to the present embodiment. FIG. 2 is a block diagram illustrating a schematic configuration of the printer 1 of the present embodiment.
As shown in FIG. 1, the printer 1 includes a supply unit 11, a transport unit 12, a carriage 13, a carriage moving unit 14, and a control unit 15 (see FIG. 2). The printer 1 controls the units 11, 12, and 14 and the carriage 13 based on print data input from an external device 20 such as a personal computer, and prints an image on the medium M. The printer 1 of the present embodiment forms a test pattern at a predetermined position on the medium M based on preset original image data, acquires a captured image of the test pattern, performs image processing, and is printed. Print correction is performed when the printed image is not appropriate.
Hereinafter, each configuration of the printer 1 will be specifically described.

The supply unit 11 is a unit that supplies a medium M (for example, printing paper) that is an image forming target to an image forming position. The supply unit 11 includes, for example, a roll body 111 (see FIG. 1) around which the medium M is wound, and a supply drive mechanism such as a drive motor and a gear train for driving the roll body. The supply drive mechanism rotates the roll body 111 based on a command from the control unit 15. Thereby, the media M wound around the roll body 111 is supplied downstream (+ Y direction) in the Y direction (sub-scanning direction).
The unit for supplying the media M is not limited to this, and for example, a configuration may be adopted in which the media M loaded on a tray or the like is supplied by being conveyed by a roller or the like.

The transport unit 12 includes a transport roller 121 and a platen 122. In addition to the driving roller driven based on the command of the control unit 15, the transport roller 121 includes a driven roller that is driven by the driving roller and sandwiches the medium M together with the driving roller.
The transport unit 12 transports the medium M supplied from the supply unit 11 onto the platen 122.

The carriage 13 includes a printing unit 16 that prints an image on the medium M and an imaging device 17 that performs imaging processing at a predetermined position on the medium M. A configuration in which a spectrophotometer is separately mounted on the carriage 13 may be used.
The carriage 13 is provided by a carriage moving unit 14 so as to be movable along a main scanning direction (X direction) intersecting with the Y direction.
The carriage 13 is connected to the control unit 15 by a flexible circuit 131, and performs printing processing (image forming processing for the medium M) by the printing unit 16 and imaging processing by the imaging device 17 based on a command from the control unit 15. carry out.
The detailed configuration of the carriage 13 will be described later.

The carriage moving unit 14 constitutes a moving mechanism that moves the carriage 13 and 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.
The carriage guide shaft 141 is disposed along the X direction, and both ends are fixed to, for example, a casing 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. When the carriage motor 142 is driven based on a command from the control unit 15, the timing belt 143 travels forward and backward, and the carriage 13 fixed to the timing belt 143 is guided by the carriage guide shaft 141 and reciprocates.

Next, the configuration of the printing unit 16 and the imaging device 17 provided on the carriage 13 will be described.
[Configuration of printing section]
The printing unit 16 is an image forming unit of the present invention, and is provided in a portion facing the platen 122, and forms an image by ejecting ink droplets onto the medium M conveyed on the platen 122.
The printing unit 16 is detachably mounted with ink cartridges (not shown) corresponding to a plurality of colors of ink, and ink is supplied from each ink cartridge to an ink tank (not shown) via a tube (not shown). Is done. Further, nozzles (not shown) for ejecting ink droplets are provided on the lower surface (position facing the medium M) of the printing unit 16 corresponding to each color. For example, piezo elements are arranged in these nozzles, and by driving the piezo elements, ink droplets supplied from the ink tank are ejected and land on the medium M to form dots.

[Configuration of imaging device]
FIG. 3 is a diagram illustrating a schematic configuration of the imaging device 17.
The imaging device 17 is an optical sensor module according to the present invention, and includes an imaging lens 171, an imaging unit 172, and a light source unit 173. For example, in the carriage 13, the imaging device 17 is disposed on the + X side and the + Y side of the printing unit 16.
The imaging lens 171 is a lens that irradiates the light emitted from the light source unit 173 onto the medium M to be measured and guides the reflected light reflected by the medium M to the imaging unit 172. Although FIG. 3 shows a single lens, it may be composed of a plurality of lens groups.

FIG. 4 is a diagram illustrating an example of the imaging unit 172.
The imaging unit 172 is a so-called RGB camera, and as shown in FIG. 4, R detection elements 172R, G detection elements 172G, and B detection elements 172B that detect the amount of received red light are arranged in a matrix (for example, a Bayer array). ). Here, the R detection element 172R includes an R color filter that transmits red light and a photoelectric conversion element that receives light transmitted through the R color filter and outputs a light reception signal. Similarly, the G detection element 172G includes a G color filter that transmits green, and a photoelectric conversion element that receives light transmitted through the G color filter and outputs a light reception signal. The B detection element 172B includes a B color filter that transmits blue light, and a photoelectric conversion element that receives light transmitted through the B color filter and outputs a light reception signal. In addition, it is good also as a structure which provides a micro lens in each detection element 172R, 172G, 172B.
The received light signals from the detection elements 172R, 172G, and 172B are input to the control unit 15 via a signal processing circuit having, for example, an IV converter, an amplifier, and an AD converter.

The light source unit 173 includes a white light source 173A that emits white light and an auxiliary light source 173B that emits auxiliary light.
The white light source 173A is a white LED (Light Emitting Diode), and emits white light by combining a blue LED and a yellow phosphor.
As the white LED, a configuration in which a red LED, a blue LED, and a green LED are combined, a configuration in which a near-ultraviolet LED is combined with a red phosphor, a blue phosphor, and a green phosphor can be considered. However, when a red LED, a blue LED, and a green LED are combined, the circuit configuration for driving each LED independently becomes complicated, and power consumption increases for driving the three LEDs. It is unsuitable as a light source. Also, when combining near-ultraviolet LEDs with red, blue, and green phosphors, the cost of near-ultraviolet LEDs is high and the intensity of some wavelengths is peaky, making it difficult to handle in color measurement. This is not suitable for performing print correction of the printing unit 16 based on the captured image as in the present embodiment. On the other hand, as in this embodiment, a white LED that combines a blue LED and a yellow phosphor does not have a peaky wavelength component and has a circuit configuration as compared with a combination of a near-ultraviolet LED and a phosphor. It can be simplified.

  The auxiliary light source 173B outputs auxiliary light for obtaining a captured image of each color image using each color ink used in the printer 1 with high resolution. Hereinafter, the wavelength of the auxiliary light emitted from the auxiliary light source 173B will be described.

In the present embodiment, as described above, a test pattern is printed on the medium M by the printing unit 16, the test pattern is imaged by the imaging device 17, and an ink ejection abnormality or the like is detected based on the obtained captured image. To do. At this time, when the difference (reflectance difference) between the reflectance of the ink color and the reflectance of the color of the medium M (white in the case of white paper) is less than the detection threshold, it is difficult to detect the test pattern. It becomes. This reflectance difference is {(reflectance of the color of the medium M) − (reflectance of the ink color of the test pattern)} × (detection sensitivity of the detection elements 172R, 172G, and 172B) × (light emission intensity of the light source unit 173). It is possible to calculate by
In addition, since the R detection element 172R, the G detection element 172G, and the B detection element 172B of the imaging unit 172 receive light through different color filters, they have different detection sensitivities. Accordingly, the reflectance difference is different in each of the R detection element 172R, the G detection element 172G, and the B detection element 172B.

FIG. 5 is a diagram showing the detected amount of reflectance difference when only the white light source 173A is used. FIG. 5 shows, for each of the detection elements 172R, 172G, and 172B, the detection amount of the reflectance difference at each of the detection elements 172R, 172G, and 172B when the test pattern of each color ink is imaged. In this embodiment, ten colors of cyan, magenta, yellow, black, light cyan, light magenta, gray, light gray, orange, and green are used as ink colors.
As shown in FIG. 5, in colors other than yellow, a reflectance difference equal to or greater than the detection threshold can be obtained by at least two of the R detection element 172R, the G detection element 172G, and the B detection element 172B. That is, in these colors, the ink color and the color of the medium M can be distinguished by at least two of the R detection element 172R, the G detection element 172G, and the B detection element 172B (a test pattern formed of ink). Can be properly identified). Therefore, a high-resolution image can be obtained by forming an image based on light reception signals output from at least two of the R detection element 172R, the G detection element 172G, and the B detection element 172B.

  On the other hand, for yellow (yellow), as shown in FIG. 5, a reflectance difference equal to or greater than the detection threshold is obtained in the B detection element 172B, but less than the detection threshold in the R detection element 172R and the G detection element 172G. I can only get the reflectance difference. In this case, the captured image is formed based only on the light reception signal from the B detection element 172B, so that the resolution is insufficient.

FIG. 6 shows a case where glossy paper is used as the medium M, the difference between the reflectance of each wavelength of the medium M and the reflectance of each wavelength of the yellow test pattern formed on the medium M, and each wavelength of the R detection element 172R. And the difference between the reflectance of each wavelength of the medium M and the reflectance of each wavelength of the yellow test pattern, and the detection sensitivity of each wavelength of the G detection element 172G. It is a figure which shows the multiplied value (G sensitivity index). The R sensitivity index and the G sensitivity index correspond to the first value in the present invention. In the example shown in FIG. 6, glossy paper is used as the medium M. However, the present invention is not limited to this, and the other white media M have substantially the same R sensitivity index and G sensitivity index.
As shown in FIG. 6, with respect to the yellow test pattern formed on glossy paper, the R sensitivity index has a low value at any wavelength and is 0.1 or less. On the other hand, the G sensitivity index takes a peak value exceeding 0.25 at 500 to 510 nm. Therefore, in the present embodiment, auxiliary light of 500 to 510 nm is emitted from the auxiliary light source 173B so that the G detection element 172G can detect the yellow test pattern formed on the glossy paper in the wavelength range of 500 to 510 nm. Let

FIG. 7 is a diagram illustrating the reflectance difference detection amount when the white light source 173A and the auxiliary light source 173B are used. In the example shown in FIG. 7, light of 505 nm is used as auxiliary light.
As shown in FIG. 7, in the present embodiment, it is possible to detect a reflectance difference equal to or greater than the detection threshold in the G detection element 172G in addition to the B detection element 172B for yellow.
That is, in any of the 10 color ink test patterns, the ink color test pattern on the medium M can be discriminated by the two or more detection elements 172R, 172B, and 172G, and a high-resolution captured image can be obtained. can get.

[Control unit configuration]
Returning to FIG. 2, the control unit 15 includes 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 20 to the CPU 154.
The unit control circuit 152 includes control circuits that respectively control the supply unit 11, the transport unit 12, the printing unit 16, the imaging device 17, and the carriage movement unit 14, and based on a command signal from the CPU 154, Control the behavior. 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 and various data for controlling the operation of the printer 1.
As various data, for example, original image data for printing a test pattern (for example, a deviation adjustment pattern), an ejection amount of each ink when forming a predetermined color, and an ink droplet for landing an ink droplet at a predetermined position Print profile data that stores the discharge timing and the like.

The CPU 154 executes various processes by reading and executing various programs stored in the memory 153. For example, the CPU 154 outputs a command signal for driving the supply unit 11, the transport unit 12, and the carriage movement unit 14 to the unit control circuit 152. As a result, the medium M is supplied from the supply unit 11 to the transport unit 12 and transported to a position where a predetermined area of the medium M faces the carriage 13 of the platen 122. Further, based on the command signal, the unit control circuit 152 controls the carriage moving unit 14 to move the carriage 13 along the X direction.
Further, the CPU 154 outputs a command signal for controlling the printing unit 16 to the unit control circuit 152 based on, for example, print data input from the external device 20. As a result, the unit control circuit 152 outputs a print control signal to the printing unit 16 and causes the medium M to eject ink to form an image.

  Further, the CPU 154 outputs a command signal to the control unit 15 to cause the imaging device 17 to perform an imaging process. Specifically, the CPU 154 controls the imaging device 17 to drive the imaging unit 172 and acquires a light reception signal (captured image) input from the imaging unit 172. Here, in this embodiment, when the imaging process is performed on the medium M on which the test pattern is printed, the CPU 154 detects both the white light source 173A and the auxiliary light source 173B when imaging the yellow test pattern. May be turned on and the auxiliary light source 173B may be turned off and only the white light source 173A may be turned on when imaging test patterns of other colors. Then, the CPU 154 detects an ink ejection abnormality based on the captured image with respect to the test pattern imaged by the imaging device 17 and performs print correction so that an appropriate printing process is performed in the printing unit 16.

[Operational effects of this embodiment]
The printer 1 of this embodiment includes a carriage 13 on which a printing unit 16 and an imaging device 17 are mounted. The imaging device 17 includes an imaging unit 172 including an R detection element 172R, a G detection element 172G, and a B detection element 172B, and a white color. A light source 173A and an auxiliary light source 173B are provided. The auxiliary light source 173B has a peak value (G sensitivity index) obtained by multiplying the difference between the reflectance of the medium M and the reflectance of yellow (ink color) of the test pattern by the detection sensitivity of the G detection element 172G. Auxiliary light of 500 to 510 nm corresponding to the value is output.
As a result, the B detection element 172B and the G detection element 172G can detect a reflectance difference equal to or greater than the detection threshold for yellow. Therefore, by using the B detection element 172B and the G detection element 172G, it is possible to capture the yellow test pattern formed on the medium M with high resolution.
For other ink colors, as shown in FIG. 5, at least two or more detection elements 172R, 172G, and 172B can detect a reflectance difference equal to or greater than a detection threshold. Therefore, in this embodiment, a high-resolution captured image can be obtained for any test pattern of each ink color.
As a result, the printer 1 can detect an ink ejection abnormality with high accuracy using a captured image of each color ink captured by the imaging device 17 and can perform an appropriate print correction. It becomes.

In the present embodiment, light having a wavelength of 505 nm is used as auxiliary light.
As auxiliary light, light having a wavelength in the vicinity of 380 nm may be used based on the R sensitivity index, but as shown in FIG. 6, the peak value in the R sensitivity index is about 0.1. In contrast, the peak value of the G sensitivity index exceeds 0.25, and the resolution of the captured image for yellow can be improved with a smaller amount of auxiliary light.

[Second Embodiment]
Next, a second embodiment according to the present invention will be described.
In the first embodiment, an example in which light having a wavelength (500 to 510 nm) corresponding to the peak value of the G sensitivity index shown in FIG. 6 is used as auxiliary light has been described. In contrast, the second embodiment is different from the first embodiment in that a wavelength corresponding to the intersection of the G sensitivity index and the R sensitivity index is used.

The printer 1 of the second embodiment is the same as that of the first embodiment, and the wavelength of auxiliary light output from the auxiliary light source 173B is different from that of the first embodiment.
That is, in the present embodiment, as the auxiliary light output from the auxiliary light source 173B, the intersection of the R sensitivity index and the G sensitivity index shown in FIG. 6, that is, the ratio between the R sensitivity index and the G sensitivity index (R sensitivity index / Light having a wavelength such that (G sensitivity index) is 0.9 or more and 1.1 or less is used.

  Here, as shown in FIG. 6, 450 nm and 580 nm can be cited as wavelengths at which the ratio of R sensitivity index to G sensitivity index (R sensitivity index / G sensitivity index) is 0.9 or more and 1.1 or less. Among these, in this embodiment, it is more preferable to use 450 nm having a large R sensitivity index and G sensitivity index as auxiliary light.

8 and 9 are diagrams showing the reflectance difference detection amount when the auxiliary light source 173B outputs auxiliary light having a wavelength of 450 nm and the white light source 173A and the auxiliary light source 173B are used. It is the figure which made the unit of the vertical axis | shaft of 8 smaller.
As shown in FIGS. 8 and 9, in the present embodiment, a reflectance difference equal to or greater than the detection threshold can be detected by the R detection element 172R, the B detection element 172B, and the G detection element 172G for yellow. . Thereby, the yellow test pattern on the medium M can be imaged with higher resolution.

[Modification]
Note that the present invention is not limited to the above-described embodiments, and the present invention includes configurations obtained by modifying, improving, and appropriately combining the embodiments as long as the object of the present invention can be achieved. Is.

  In the first embodiment, light having a wavelength of 505 nm is used as auxiliary light. However, the present invention is not limited to this. For example, light having a wavelength of 380 nm that is the peak value of the R sensitivity index may be used. In this case, the light intensity of the auxiliary light is more required than light having a wavelength of 505 nm, but a high-resolution captured image for yellow can be obtained using the R detection element 172R and the B detection element 172B. .

  Moreover, although the structure which provides the one auxiliary light source 173B was illustrated in the said embodiment, it is good also as a structure which provides the some auxiliary light source 173B. In this case, a first auxiliary light source that outputs auxiliary light having a wavelength of 505 nm and a second auxiliary light source that outputs auxiliary light having a wavelength of 380 nm may be used. In such a configuration, it is possible to acquire a higher-resolution captured image for yellow using three elements of the R detection element 172R, the G detection element 172G, and the B detection element 172B.

  The same applies to the second embodiment, and the configuration using 450 nm auxiliary light is exemplified. However, the configuration using 580 nm auxiliary light may be used, and the configuration using both 450 nm auxiliary light and 580 nm auxiliary light may be used. Good.

  In the first embodiment, the white light source 173A and the auxiliary light source 173B are turned on when imaging a yellow test pattern, and the auxiliary light source 173B is turned off when imaging a test pattern of other colors. Although an example of imaging with only the light source 173A has been shown, the present invention is not limited to this. For example, the captured image may be captured by turning on both the white light source 173A and the auxiliary light source 173B for all color patterns.

  In addition, the specific structure for carrying out the present invention may be configured by appropriately combining the above-described embodiments and modifications within the scope that can achieve the object of the present invention, and may be appropriately changed to other structures and the like. May be.

  DESCRIPTION OF SYMBOLS 1 ... Printer (image forming apparatus), 13 ... Carriage, 16 ... Printing part (image forming part), 17 ... Imaging device, 171 ... Imaging lens, 172 ... Imaging part, 172B ... B detection element, 172G ... G detection element, 172R ... R detection element, 173 ... light source unit, 173A ... white light source, 173B ... auxiliary light source, M ... media (measuring object).

Claims (4)

A light source;
An imaging unit that receives reflected light that is reflected from a measurement object that is irradiated from the light source and formed on the medium; and
The imaging unit has an R detection element, a B detection element, and a G detection element corresponding to each color of red, blue, and green,
The light source includes a white light source that emits white light and an auxiliary light source that emits auxiliary light.
The auxiliary light is light having a wavelength corresponding to a peak value obtained by multiplying the difference between the reflectance of the medium and the reflectance of the measurement object and the detection sensitivity of the R detection element or the G detection element at each wavelength. An optical sensor module characterized by The optical sensor module according to claim 1,
The measurement object is a yellow image;
The optical sensor module, wherein the auxiliary light is light having a wavelength of 500 to 510 nm. A light source;
An imaging unit that receives reflected light that is reflected from a measurement object that is irradiated from the light source and formed on the medium; and
The imaging unit has an R detection element, a B detection element, and a G detection element corresponding to each color of red, blue, and green,
The light source includes a white light source that emits white light and an auxiliary light source that emits auxiliary light.
The auxiliary light is calculated by calculating a first value obtained by multiplying the difference between the reflectance of the medium and the reflectance of the measurement object and the detection sensitivity of the R detection element or the G detection element at each wavelength. An optical sensor module, wherein the ratio of the first value to the detection element and the first value to the G detection element is light having a wavelength of 0.9 to 1.1. The optical sensor module according to any one of claims 1 to 3,
An image forming unit for forming an image on the medium;
An image forming apparatus comprising:

Images