JP2001054964A - Imaging apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a malfunction caused by the leakage of light and reflected light from another apparatus by arranging a recording medium detector and a reflection characteristic detector to face each other. SOLUTION: After printing paper 20 is extracted from a paper tray 80, the reflective characteristics of the paper 20 are measured by a measurement part 81. A darkroom box is formed by making a box including a light source and a sensor adhere to the paper 20, and a darkroom box is used also between a paper sensing plate 83 and the paper 20. When the paper 20 is not set in the tray 80, the sensor measures the sensing plate 83. Since the plate 83 is processed to absorb light and absorbs light from the light source without reflecting it, the sensor outputs a low value. In this case, the absence of the paper 20 is recognized by a printer driver. When the output of the sensor is high in value, the specification of the paper 20 from measured data and the change of printing are made possible.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a color printer that changes a printing method based on information on a recording medium such as paper used for a color printer.

[0002]

2. Description of the Related Art Generally, a recording medium used in a color printer is properly used depending on the purpose. When printing high-quality images such as photographs, use special paper with a special coating to improve color reproducibility, and use plain paper when printing low-quality images such as documents. Used. There are various other recording media used for the printer, such as special paper for high-resolution printing and special paper for low-resolution printing.

As described above, when different printing processes are performed for each recording medium, for example, in Japanese Patent Application Laid-Open No. 9-190113,
The difference or the like between the multiple areas of the recording paper is calculated and calculated as the uniformity of the recording paper surface, and whether the value of the uniformity is large or small is determined as dedicated paper or general-purpose paper. It describes that parameter settings are changed.

Japanese Patent Application Laid-Open No. 9-69960 discloses that the type of printing paper is identified, and color conversion of print data is performed using a color conversion table corresponding to the type of printing paper. ing.

[0005]

As described above, there are various methods for identifying the type of printing paper.

The present invention is directed to a device utilizing the reflection characteristics of a recording medium to identify the type of printing paper. In this case, malfunction may occur due to light leakage or light reflected from another device.

An object of the present invention is to provide an image forming apparatus for preventing such a malfunction.

[0008]

In order to achieve the above object, an image forming apparatus according to the present invention comprises a printing unit for printing on a recording medium, a transport roller for guiding the recording medium to the printing unit,
A recording medium detector that detects whether a recording medium has been sent from the conveyance roller, a reflection characteristic detector that reads the reflection characteristic of the surface of the recording medium sent from the conveyance roller, and a processing unit that controls printing in the printing unit. Wherein the recording medium detector and the reflection characteristic detector are arranged to face each other, and the surface of the recording medium detector is processed to absorb light.

Further, the processing section of the image forming apparatus of the present invention comprises:
A printing process is selected and executed based on a reflection characteristic from a reflection characteristic detector from among a plurality of printing processes.

Further, the reflection characteristic detector of the image forming apparatus according to the present invention is a spectral altimeter.

Further, the reflection characteristic detector of the image forming apparatus according to the present invention has a plurality of photo sensors.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below in detail with reference to the block diagram of FIG.

The present invention relates to a printer 17 and a printer driver 16 which measure print paper with a measuring device, automatically set a print processing method from measured data, and perform print processing and printing. 10, print paper setting unit 11, print paper data storage unit 12, image data storage unit 13, print processing unit 1
4, the printing unit 15.

The printer driver 16 performs print operations, print processing, and print paper settings, and may be provided on a personal computer or on the printer 17. In addition, the functions of the printer driver 16 can be shared between the personal computer and the printer 17. If there is a printer driver 16 on the personal computer, the functions of the printer driver 16 are executed by software,
When the printer driver 16 is mounted on the printer 17, all the functions of the printer driver 16 can be implemented as hardware, or the processing can be performed by software using an embedded processor.

The print paper measuring section 10 measures print paper. The print paper data storage unit 12 stores print paper data such as glossy paper and special paper recommended by the printer corresponding to the measurement data output by the print paper measurement unit 10, and is optimal for each of the recommended print papers. Print processing data for performing various print processing is stored in the print processing unit 14. The print paper setting unit 11 compares the measurement data from the print paper measurement unit 10 with the print paper data registered in the print paper data storage unit 12 and sets the measured print paper. If there is no print paper data corresponding to the measurement data in the print paper data storage unit 12, the closest print paper is provisionally set and the measurement data is passed to the print processing unit. The image data storage unit 13 stores image data to be printed. The printing unit 15 performs printing from the image data after the print processing from the print processing unit 14.

The print processing unit 14 executes an optimum print process on the print paper set by the print paper setting unit 11.

Since there are various types of print processing depending on the print format and printer characteristics, FIG. 1B shows a specific block diagram of a print processing unit of an ink jet printer as an example.

The print processing unit 14 includes a print processing data storage unit 140, a print processing setting unit 141, and a data processing unit 142. Print processing data storage unit 14
0 stores data for performing optimal print processing on various print papers recommended by the printer. The print processing setting section 141 is a print paper setting section 1
The print processing data and device profile corresponding to the print paper set in step 1 are selected or changed from the print processing data storage unit 140 and set. Hereinafter, a specific description will be given.

The general data processing of an ink-jet printer includes an enlargement / reduction processing for changing an image data size according to a print paper size or a user setting, and a color signal (for example, an RGB signal) input to the printer as a color material color of the printer. (CMY, CMYK, etc.) and a gradation conversion process for reducing the number of gradations of the color signal to the number of gradations that can be output by the printer. The above data processing
Some are executed by software as a printer driver on a personal computer, while others are executed by hardware on a printer.

Since such data processing needs to be changed depending on the print paper in order to perform optimum printing, the print processing data storage section 140 stores print processing data optimal for each print paper.

Specifically, there are a data processing method (a function of data processing in the case of software, a data processing circuit in the case of hardware), a coefficient value used during calculation, a table value, and a device profile to be described later. For example, when the print paper set by the print paper setting unit 11 is plain paper, high-density printing is not performed on print paper, such as plain paper, in which color materials easily bleed during enlargement / reduction processing. Sets the method of linear interpolation calculation (two-arrested bar method), which is the method. Further, in the color conversion processing, it is general to perform a matrix operation or a table operation in order to absorb the characteristics of the color materials and the characteristics of the printer. Taking a one-dimensional table operation as an example, when the input color signal is RGB, a table in which the input and output of the signal value are associated with each color of RGB is used. Since plain paper has a stronger yellow component than specialty paper such as glossy paper, a table is set in which the output value of the yellow component is suppressed. Further, a profile process can be performed by setting a device profile for plain paper in the pre-process of the print process.

The print paper temporarily set by the print paper setting section 11 is set by converting print processing data and device profile data corresponding to the print paper based on the measurement data. Although the conversion method is not limited, the data from the measuring device is data on the whiteness of the printing paper (this data will be described in the embodiment because it differs depending on the measuring device for measuring the printing paper). If the print processing data of the temporarily set print paper is more yellowish, it is possible to reduce the ink color yellow of the printer as a whole. In addition, the printing unit 1
It is also possible to measure the print paper printed in 5 by the print paper measurement unit 10 and to convert the print processing data to stabilize the device of the printer by the print processing setting unit 141.

The data processing section 142 executes the print processing set by the print processing setting section 141 on the image data storage section 15.
And performs digital signal processing of the image data. The data processing consists mainly of enlargement for adjusting the image size, color conversion for converting the color signal of the image to the ink color signal to the printer, and gradation processing for converting the number of gradations of the ink color signal to the printer output level Is done.

The data processing is changed depending on the printing paper. This is because the whiteness of the paper, which is the basis of color reproduction, changes. Relatively low quality print paper such as plain paper absorbs light of short wavelength easily (it looks yellowish)
Therefore, high color reproducibility cannot be obtained. Therefore, two methods are generally selected: one is to simply perform data processing to increase the printing speed, and the other is to perform data processing for plain paper strictly and print a proper image on plain paper. Special paper is coded to absorb less light in order to pursue high color reproduction. For this reason, high color reproduction can be achieved by strictly performing data processing for exclusive use paper. Therefore, by measuring the whiteness of the print paper and changing the data processing based on the measured data, printing errors due to paper settings are eliminated, and high color reproduction is possible by performing optimal print processing on print paper. Become.

In addition, ICC profile processing, which is standardly installed in various OSs as a color management system in recent years, can be included in the print processing. The ICC profile converts color signals for the purpose of reproducing the same color between image input / output devices such as a monitor and a printer, and depends on the device by using a device profile that describes input and output device characteristics. Color conversion that does not occur can be realized. A printer device profile is prepared for each print sheet used for printing. Therefore, if the print paper can be specified, the device profile can be automatically specified. Also, the device profile is created based on the white point of the print paper, and if there is no device profile corresponding to the measured white point of the print paper, the profile closest to the white point can be used. is there.

FIG. 1C shows a flowchart of FIG.

When a print operation 110 occurs, a measurement 111 of the print paper is performed. Next, comparison 112 of the measured data with the registered print paper data is performed. If the registered data matches, the print paper corresponding to the registered data is set 113, and the print processing setting 114 prepared for each print paper is performed. If there is no registered data corresponding to the measured print paper, the print paper of the registered data closest to the measured data may be set, or the print processing data is changed from the measured data.
4 to set 115 print processing. The printing process is executed 116 on the image data, and the printing 117 is performed.

FIG. 2 shows the configuration of the embodiment of the present invention. Print operation, print paper settings, print processing settings, and print processing are performed by the printer driver 1 installed in the personal computer.
6. The measuring unit 10 of the print paper 20
The printing unit 15 is mounted on a printer 17.

Hereinafter, a specific description will be given.

When a print operation is executed from the printer driver 16, the printer 12 measures the set print paper 20 and transmits the measurement data 22 to the printer driver 16. The data transmission method is not limited. In this embodiment, the parallel port bidirectional communication is used. The printer driver 16 executes optimal printing processing for the printing paper 20 set in the printer 12 from the measurement data 22. The printer 12 receives the data 21 after the print processing, and the printing unit 15 performs printing.

Further, it is also possible to display the set print paper information on a monitor of a personal computer to obtain the user's confirmation. Thereby, it is possible to confirm whether the print paper desired by the user is set in the printer.

In this embodiment, since all the operations of the print driver are performed on the personal computer side, the data of the print paper data storage unit 12 and the print processing data storage unit 140 are stored as files of the personal computer. The samples used in the selection of print papers this time are five types, two of which are commercially available paper dedicated to inkjet printers, glossy film paper (hereinafter, p1) and glossy paper (hereinafter, p2). Others are high-quality (hereinafter, p3), low-quality plain paper (hereinafter, p4), and plain paper for leaflets (hereinafter, p5).

In the first embodiment, a spectrophotometer is mounted on the measuring section of the printer, the spectral reflectance of the print paper is measured, and the white point is determined to set the print paper and print processing. FIG. 3A shows the configuration of the measuring unit 16. The spectral reflectance of the printing paper 20 set in the printer is measured by the spectrophotometer 30, the white point is obtained, and the measured data 22 is transmitted to the printer driver of the personal computer. The printer driver specifies a print sheet from the measurement data 22 and executes an optimal print process for the print sheet. The data in the print paper data storage unit 12 used in this embodiment is a white point.

The details will be described below.

The spectrophotometer 30 irradiates a light source of standard light such as D50, D65 or the like with the print paper 20 in close contact with the light source, and measures the spectral reflectance to obtain a white point for the standard light used as the light source. The calculation for obtaining the white point from the measured value of the spectrophotometer 30 may be performed in the printer, but when the measured value is used for the printing process, it may be transmitted to the printer driver as it is.

FIG. 5A shows the white point measured for each of the five types of print paper samples.
The result of mapping on the 0 chromaticity diagram is shown. Although the white points of the special paper such as p1 and p2 are relatively present around the white point of the D50 light source, it can be seen that the white points move in the yellow direction on the chromaticity diagram as the paper quality decreases.

FIG. 4 shows a flowchart of the first to fourth embodiments. Since only the A section 41 in the flowchart is different in each embodiment, the entire flow will be described in the first embodiment, and only the flowchart of the A section 41 will be described in the second to fourth embodiments.

First, the flow chart of the first embodiment will be described. The A section 41 uses 46.

The measuring section of the printer, which has received the print execution command 40 from the printer driver of the personal computer, measures the spectral reflectance of the printing paper using a spectrophotometer, and determines the white point (hereinafter referred to as Wpt_P) 46 of the printing paper.
Ask for. This measured value is sent to the printer driver 1 of the PC.
Send to 6. The print paper is set 42 based on the value of Wpt_P46. For example, the measured value of Wpt_P is x = 0.
In the case of 34591, y = 0.35789.0, since it corresponds to the white point of sample P1 from FIG. 5B, it is set as the print paper of P1. Other print papers can be set in the same manner. If there is no print paper corresponding to the measured value of Wpt_P, the print paper having the white point closest to the measured value is provisionally set 410.

As a method for specifying the print paper using the white point, the distance L between the measured Wpt_P and the white point Wpt_D50 of the standard light used as the light source (Wpt_D50 since the light source D50 is used) is used. realizable. As shown in FIG. 5A, the higher the quality of the printing paper, the higher the white point becomes.
It approaches t_D50. In addition, since the white points of various printing papers are almost on a straight line,
The print paper can be specified by the distance from pt_D50. For example, when the distance L between the measured values Wpt_P and Wpt_D50 is 7.0 × 10 ⁻³ , Wp is determined from FIG.
Since it is closest to L of t_P1, the print paper can be specified as P1. Other print papers can be similarly specified. In addition, as shown in FIG. 5, when specifying two types of special paper and plain paper, a special paper area centering on Wpt_D50 is determined, and within that area,
The determination can be made outside the area.

After setting print paper 42, device profile processing 43 is performed, print processing data corresponding to the print paper is set, and print processing is executed 44. In addition, when the temporary setting 410 of the print paper is performed, the profile processing and the print processing are performed using the profile data or the print processing data of the temporarily set print paper. Also, the profile data and print processing data are converted 41 based on the measurement data 22.
It is also possible to execute 412 the profile process and the print process. Finally, printing 45 is performed.

The print paper information from the measured data can be displayed on a screen of a personal computer or a message display of a printer, and the print paper information can be provided to the user.

In the second embodiment, a light source and a photo sensor are mounted on the measuring section of the printer, the wavelength range of the printer paper is measured at one location, and the print paper and print processing are set from the data. FIG. 3B shows the configuration of the measurement unit. Light source 32 is applied to print paper 20 set in the printer.
The measurement data 22 is transmitted to a printer driver of a personal computer. The printer driver specifies a print sheet from the measurement data 22 and executes an optimal print process for the print sheet. The data in the print paper data storage unit 12 used in this embodiment is a measured value of a photo sensor.

Since the irradiation of the light source 32 and the measurement of the photo sensor 33 must be performed in an environment that blocks external light, the dark room box 31 is used. However, the means for shielding light is not limited. Further, in this embodiment, the D50 light source is used, but another light source may be used. However, it is necessary to make changes while maintaining the relationship between the light source and the peak value of the photosensor.

FIG. 6A shows the results of measuring the spectral reflectance in the visible region of five print paper samples.
In the blue region of 380 to 480 nm, the spectral reflectance of dedicated paper such as p1 and p2 sharply rises, while p3 and p2
Plain papers such as 4, p5 have a gentle rise. This means that low-quality paper, such as plain paper, tends to absorb short-wavelength light (it looks yellow). Especially F2
In the vicinity of (about 460 nm), there is a large difference in the reflectance between the special paper and the plain paper. Therefore, a photosensor having a peak value as shown in FIG. 7A is used. The print paper set in the printer is specified from the output value of the photo sensor. Further, the peak value of the photo sensor may be changed according to the type of print paper used in the printer.

FIG. 4B shows a flowchart of the measuring section of the second embodiment. The A section 41 uses 47.

The printer, which has received a print execution command from the printer driver of the personal computer, irradiates light from a light source onto the set printing paper and measures 47 with a photo sensor. The data F after A / D conversion is 8 bit information (max: 2
55, min: 0), for example, when the measured value is 250, the print paper can be identified as P1 from the print paper information shown in FIG. Other print papers can be similarly specified. When the print paper is specified by a printer, the data after the A / D conversion of the photo sensor as shown in FIG. 6B can be stored in a ROM, and the print paper can be specified by a personal computer. In the case of performing, the data after the A / D conversion can be used by having it on the printer driver.

In the third embodiment, two photosensors and a light source are mounted on the measuring section of the printer, two wavelength ranges of the printer paper are measured at two locations, and the print paper and print processing are set based on the measured data. . The data in the print paper data storage unit 12 used in this embodiment is a measured value of a photo sensor. When such two wavelength ranges are required, instead of using two photo sensors,
A method in which the wavelength of the light source is fluctuated twice and measurement is performed twice with one photosensor is also possible.

FIG. 3C shows the configuration. As shown in FIG. 6A, the spectral reflectance of the special paper such as p1 and p2 sharply rises in the blue region of 380 to 480 nm,
Plain paper such as p3, p4, and p5 has a gentle rise. Therefore, if the width of the rise can be measured, it is possible to specify the print paper. For this reason,
As shown in FIG. 7B, the photo sensor has F1 in the blue region.
(About 380 nm) and F
Two types having a peak sensitivity around 2 (about 460 nm) are used.

The rising width is measured from the outputs from the two photo sensors 35. The measurement data 22 is transmitted to the printer driver of the personal computer. The printer driver specifies a print sheet from the measurement data 22 and executes an optimal print process for the print sheet. Further, the peak value of the photo sensor 35 may be changed according to the type of the printing paper 20 used in the printer. Since the irradiation of the light source 34 and the measurement of the photosensor 35 must be performed in an environment that blocks external light, the dark room box 31 was used.

FIG. 4C shows a flowchart of the measuring section according to the third embodiment. The A section 41 uses 48.

The printer, which has received a print execution command from the printer driver of the personal computer, irradiates light from a light source to the set printing paper, and measures 48 with two photo sensors. The rising width X is obtained from the data F1 and F2 after the A / D conversion. When the data after A / D conversion is 8-bit information (max: 255, min: 0), for example, when the measured rise width is X = 68, the print paper can be identified as P1 from the print paper information in FIG. it can. Other print papers can be similarly specified. When specifying the print paper by a printer, FIG.
The data X after the A / D conversion of the photo sensor can be used by storing the data in a ROM as shown in FIG. You can use it by holding it on top.

In the fourth embodiment, a CCD sensor and a light source are mounted on a measuring section of a printer, print paper is measured, and print paper and print processing are set from the data. Print paper data storage unit 12 used in this embodiment
Are data measured by the CCD sensor. FIG. 3D shows the configuration. As shown in FIG. 6, the spectral reflectance of dedicated paper such as p1 and p2 sharply rises in the blue region of 380 to 480 nm, whereas plain paper such as p3, p4 and p5 rises gently. A blue-filtered CCD sensor 37 for obtaining the wavelength range as shown in FIG. 14 for obtaining the wavelength range around 400 nm is used. This C
The measurement data 22 of the CD sensor 37 is transmitted to the printer driver of the personal computer. The printer driver uses measurement data 2
2, the print paper is specified, and print processing optimal for the print paper is executed. Since the irradiation of the light source 36 and the measurement of the CCD sensor 37 must be performed in an environment that blocks external light, the dark room box 31 was used.

FIG. 4D shows a flowchart of the measuring section according to the fourth embodiment. A part 41 uses 49.

The printer, which has received a print execution command from the printer driver of the personal computer, irradiates the set printing paper with light from a light source, measures the light with a CCD sensor, and
/ D conversion and conversion 49 into luminance data C. C is data on the intensity of light reflected from the print paper by the light from the light source. The data after A / D conversion is 8-bit luminance information (max: 2
55: white, min: black), for example, the measured C is 250
In the case of, the print paper is P from the print paper information in FIG.
1 can be specified. Other print papers can be similarly specified. When the print paper is specified by a printer, the data C after A / D conversion of the CCD sensor as shown in FIG. 6 can be used by storing it in a ROM, and when the print paper is specified by a personal computer. Can be used by having the data C after A / D conversion in a printer driver.

A specific example in which the measuring instruments of Examples 1 to 4 are mounted on a printer will be described as Example 5 with reference to FIG. The printer typically has a paper tray 8 for storing printer paper 20.
0, a roller 84 for feeding paper, and a printing unit 82 for printing.

The configuration in which the measuring instrument is mounted on the printer is the same as the printer described above, except that the measuring section 81 for the printing paper 20 is provided. Hereinafter, a specific description will be given. When the print command is executed, the paper feed roller 84 of the printer pulls out the print paper 20 from the paper tray 80. In the printer of the type shown in the figure, since the print surface of the print paper 20 is set downward on the paper tray 80, the measurement is performed upward, but the measurement direction can be changed depending on the configuration of the printer.

The measuring section 81 measures the printing paper 20. In the sensors used for measuring the paper in Examples 2 to 4, since it is necessary to block the external light and perform the measurement, the print paper 20
It is necessary to have a mechanism for providing a dark room between the light source and the measuring instrument. Here, a box containing the light source and the sensor was brought into close contact with the print paper 20. This is a dark room box.
The inner wall of the darkroom box is processed to completely absorb light. Further, a dark room box was used between the paper detection plate 93 and the print paper 20 used for paper detection. This paper detection plate is also processed to completely absorb light, like the inner wall of the dark room box.

After the paper has been fed from the paper feed roller 84, the print paper 20 is measured. If the print paper 20 is not set on the paper tray 80, the paper cannot be fed and the sensor measures the paper detection plate 83. Since the paper detection plate 83 is processed to completely absorb light as described above, it absorbs light from a light source and hardly reflects light. For this reason, the sensor outputs a low value.
In this case, the printer driver can recognize that there is no print paper 20. When the output of the sensor is a high value, it is possible to specify the printing paper 20 and change the printing process from the measurement data. After the print processing or in parallel with the print processing, paper feeding and printing are performed.

FIG. 9 is a block diagram showing a part related to the measurement of print paper.

The printer driver 90 is used by a user who operates the printer to perform a printing operation, and executes printing and print processing x. Normally, the operation is performed using a monitor on a personal computer. However, an operation function may be provided in the printer body. The printer control device 101 performs mechanical control on the printer side. The light source 92 and the sensor 93 measure the print paper 20. The output value of the sensor 93 is converted into a digital signal by the A / D converter 94, and then transmitted to the printer driver 90 by the output device 95. When the printer driver 90 is provided in a personal computer, the printer driver 90 can be executed by an interface device (for example, via Centronics) for transmitting and receiving data between the personal computer and the printer. If the printer driver 90 is on the printer, the output device 95
No need to go through. The paper feed roller 92 takes out the print paper 20 from the paper tray in order to measure the print paper 20 after the print execution command from the printer driver 90.

FIG. 10 is a timing chart of this block diagram.

The printer controller 91 which has received the print operation signal 100 from the printer driver 90 issues a paper feed command 102 to the paper feed roller 84. When the paper feed is completed, the light source 92 starts irradiating 103 on the print paper 20, and simultaneously performs the measurement 104 of the sensor 93 and the A / D converter 105 of the measurement result by the A / D converter 104. When the measurement 104 is completed, the output device 95 transmits the measurement result to the print driver 90 106. If the print driver 90 is installed in the printer, the transmission 106 is not necessary. The measurement result may be a result of specifying the print paper 20 on the printer side. The print driver 90 specifies the print paper 20 from the measurement result, changes the print processing, and automatically executes printing. Further, it is also possible to check the print paper information specified by the printer driver or output an error message to the user who performs printing, and perform print execution 101 from the user.

[0064]

As described above, according to the present invention,
By measuring the print paper with a measuring instrument and specifying the paper based on the information and automatically changing the print processing method, the printing operation is simplified, and printing errors due to paper settings are eliminated. Further, by selecting an optimal print processing method from the measurement data of the print paper, higher color reproduction can be realized.

[Brief description of the drawings]

FIG. 1 (a) is a block diagram of the present invention.

FIG. 1B is a detailed block diagram of a print processing unit in FIG. 1A.

FIG. 1 (c) is a flowchart of a block diagram of the present invention.

FIG. 2 is a configuration diagram of an entire embodiment of the present invention.

FIG. 3 is a configuration diagram of a measurement unit according to the first to fourth embodiments of the present invention.

FIG. 3A is a configuration diagram of a measurement unit according to the first embodiment.

FIG. 3B is a configuration diagram of a measurement unit according to a second embodiment.

FIG. 3C is a configuration diagram of a measurement unit according to a third embodiment.

FIG. 3D is a configuration diagram of a measurement unit according to a fourth embodiment.

FIG. 4 is a flowchart of Embodiments 1 to 4 of the present invention.

FIG. 4A is a flowchart of a measurement unit according to the first embodiment.

FIG. 4B is a flowchart of a measurement unit according to the second embodiment.

FIG. 4C is a flowchart of the measurement unit according to the third embodiment.

FIG. 4D is a flowchart of a measurement unit according to the fourth embodiment.

FIG. 5 shows a white point value of print paper.

FIG. 5A is a graph of a white point value of a print sheet measured as a sample.

FIG. 5B is a white point value of a print sheet measured as a sample.

FIG. 6 shows the spectral reflectance of a print sheet.

FIG. 6 (a) is a graph of the spectral reflectance of print paper measured as a sample.

FIG. 6 (b) is a value for specifying print paper obtained from the spectral reflectance of print paper measured as a sample.

FIG. 7 shows a peak value of a sensor sensitivity for measuring print paper used in Examples 2 to 4.

FIG. 7A shows a peak value of a sensor sensitivity for measuring print paper in the second embodiment.

FIG. 7B shows a peak value of a sensor sensitivity for measuring print paper in the third embodiment.

FIG. 7C illustrates a peak value of a sensor sensitivity for measuring print paper in the fourth embodiment.

FIG. 8 is a configuration diagram of an embodiment in which the present invention is mounted on a printer.

FIG. 9 is a block diagram of a portion related to print paper measurement.

FIG. 10 is a timing chart of a block diagram of a portion relating to print paper measurement.

[Explanation of symbols]

10 print paper measuring unit, 11 print paper setting unit, 12 print paper data storage unit, 13 printing unit,
14 print processing unit, 15 image data storage unit, 1
6, 90 ... printer driver, 17 ... printer, 20 ...
Print paper, 21 ... Image data after print processing, 2
2 ... measurement data, 30 ... spectrophotometer, 31 ... dark room box, 32 ... light source corresponding to 33, 33 ... photo sensor, 34
... 35 light sources, 35 ... two photo sensors, 36 ...
37 light source, 37 ... CCD sensor, 40 ... print execution instruction, 41, 42, 104, 113 ... print paper setting, 43 ... profile processing, 44 ... print processing,
45, 118: printing, 46: measuring method of Example 1, 47
... the measuring method of Example 2, 48 ... the measuring method of Example 3, 4
9 Measurement method of Example 4, 80 Paper tray, 81 Measurement part, 82 Printing part, 83 Paper detection plate, 84 Paper feed roller, 91 Printer control device, 92 Light source, 93 Sensor 94 A / D converter, 95 output device, 100
Print operation command 101 print execution command 102
... paper feed by paper feed roller, 103: irradiation of light source, 105
... A / D conversion, 106 ... Data transmission, 110 ... Print operation, 111 ... Print paper measurement, 112 ... Print paper data comparison, 114 ... Print processing data setting, 1
15: provisional setting of print paper, 116: change and setting of print processing data, 117: print processing of image data,
140: print processing data storage unit; 141: print processing setting unit; 142: data processing unit; 410: temporary setting of print paper; 411: data conversion of print processing;
12 Profile and print processing.

Claims (4)

[Claims] A printing unit that prints on a recording medium; a conveying roller for guiding the recording medium to the printing unit; a recording medium detector that detects whether the recording medium has been sent from the conveying roller; A reflection characteristic detector that reads the reflection characteristic of the surface of the recording medium sent from the roller, and a processing unit that controls printing in the printing unit, wherein the recording medium detector and the reflection characteristic detector face each other. An image forming apparatus, wherein the surface of the recording medium detector is processed so as to absorb light. 2. The image forming apparatus according to claim 1, wherein the processing unit selects and executes a print process from a plurality of print processes based on a reflection characteristic from the reflection characteristic detector. 3. The image forming apparatus according to claim 1, wherein the reflection characteristic detector is a spectral altimeter. 4. The image forming apparatus according to claim 1, wherein the reflection characteristic detector has a plurality of photo sensors.