JP5672780B2 - Image forming apparatus - Google Patents

Description

The present invention relates to images forming device.

Patent Document 1 proposes a method for discriminating the paper quality of paper sheets by using two types of light with wavelengths from 800 nm to 2200 nm and using the difference in absorbance between the photometric values as a paper quality identification method. Yes.
In Patent Document 2, a near-infrared absorption spectrum is measured with a Fourier transform type near-infrared analyzer in a wavelength range of 1300 to 1500 nm, and for the measured near-infrared absorption spectrum, an absorbance conversion process, a first derivative process, By performing a combination of one or more of the secondary differentiation process and the standardization process, the content discrimination data of at least one of the paper filler and the content is obtained, the content discrimination data, There has been proposed a method for comparing authenticity with predetermined content standard data and determining authenticity of a sheet that requires anti-counterfeiting.

JP2002-245511 JP-A-2005-275603

In the present invention, the content of used paper pulp in the recording medium to be detected is more accurately compared to the case where the principal component analysis is performed without excluding the first wavenumber band in the present invention during the principal component analysis of the near infrared spectrum. An object of the present invention is to provide an image forming apparatus for detection.

According to the first aspect of the present invention, there is provided a transfer unit that transfers a toner image on a photosensitive member onto a recording medium, a fixing unit that fixes the transferred toner image on the recording medium, and a measurement before the transfer unit transfers the toner image. Detecting means for detecting the used paper pulp content of the recording medium based on the near-infrared spectrum of the recording medium, and the more used paper pulp content detected by the detecting means, the more the transfer current of the transferring means, the transfer An image forming apparatus comprising: a control unit that increases at least one of a voltage and a fixing temperature of the fixing unit ;
The detection means includes a near-infrared spectrum of a plurality of types of first recording media having different waste paper pulp contents, and content data indicating the waste paper pulp content of each of the plurality of types of first recording media. Corresponding to absorption by stretching vibration of oxygen atoms and hydrogen atoms in the near-infrared spectrum of each of the first recording medium obtained by the first obtaining means and the first obtaining means obtained by the first obtaining means The first principal component analysis means for performing principal component analysis on a wave number band other than the first wave number band to be generated to create a principal component analysis model, and the first recording medium for each of the plurality of types of first recording media. First computing means for computing a principal component score for the first principal component of the plurality of principal components obtained by the principal component analysis means of
The main component score of each of the plurality of types of first recording media calculated by the first calculation means, and the inclusion of each of the plurality of types of first recording media acquired by the first acquisition means. A regression analysis unit that performs regression analysis based on the correlation with the amount data, and a regression equation calculating unit that calculates a regression equation, and a used paper pulp content conveyed from the sheet feeding tray between the sheet feeding tray and the transfer unit About the near-infrared spectrum of the 2nd recording medium acquired by the 2nd acquisition means acquired by measuring the near-infrared spectrum of the 2nd recording medium which is the candidate for detection, and the 2nd acquisition means, Compared to the near infrared spectrum of each of the plurality of types of first recording media acquired in the first acquisition step, and based on the principal component analysis model created by the first principal component analysis means, The first of the main components Waste paper pulp content corresponding to the principal component score obtained by the second computing means using the second computing means for computing the principal component score for the component and the regression equation calculated by the regression equation calculating means And a detecting means for detecting the content of used paper pulp of the second recording medium .

Invention, the first frequency band is, 4500cm ^-1 or 4600cm ^-1 The following frequency band, and 7020cm ^-1 or 7280cm ^-1 are the following frequency band according to claim 1 Symbol placement of image forming according to claim 2 Device.
Invention, the first frequency band is, 4190cm ^-1 or 4270cm ^-1 The following frequency band, 4500cm ^-1 or 4670cm ^-1 The following frequency band, 4900cm ^-1 or 5360cm ^-1 The following wave numbers according to claim 3 band, an image forming apparatus according to claim 1 or claim 2 which is less frequency band 7000 cm ^-1 or 7300cm ^-1.

According to a fourth aspect of the invention, the control means corresponds to at least one of the fixing temperature, the fixing speed, and the fixing pressure in the fixing means corresponding to the waste paper pulp content detected by the detecting means. each is an image forming apparatus according to any one of claims 1 to 3, characterized in that set to a predetermined value.
In the invention according to claim 5 , the control means corresponds to at least one of the transfer current, the transfer voltage, and the transfer pressure in the transfer means corresponding to the waste paper pulp content detected by the detection means. the image forming apparatus according to any one of claims 1 to 4, characterized in that setting each predetermined value by.

According to the first aspect of the present invention, compared with the case where the detection device according to the present invention is not provided, the waste paper pulp content in the recording medium to be detected is detected with high accuracy, and the waste paper pulp content in the recording medium to be image-recorded is detected. The image recording process according to the above is realized.

According to the invention of claim 2, the waste paper pulp content of the recording medium can be detected more accurately, faster and more easily than in the case where the wave number band in the present invention is not used as the wave number band to be excluded during the principal component analysis. Thus, an image recording process according to the waste paper pulp content of the image recording target recording medium is realized .

According to the invention of claim 3 , the waste paper pulp content of the recording medium can be detected more accurately, faster and more easily than in the case where the wave number band in the present invention is not used as the wave number band to be excluded during principal component analysis. Thus , an image recording process according to the waste paper pulp content of the image recording target recording medium is realized .

According to the invention of claim 4 , the image quality of the image recorded on the recording medium can be improved without depending on the waste paper pulp content contained in the recording medium.

According to the fifth aspect of the present invention, it is possible to improve the image quality of an image recorded on the recording medium without depending on the waste paper pulp content contained in the recording medium.

It is a functional block diagram which shows the detection apparatus which concerns on this Embodiment. (A), (B) It is a schematic diagram which shows an example of the apparatus which measures a near-infrared spectrum. It is a diagram which shows an example of the near-infrared spectrum of several types of recording media from which used paper pulp content differs used for regression line preparation. (A), (B), (C) It is a diagram which shows an example of the spectrum after pre-processing to the near-infrared spectrum shown in FIG. It is a graph which shows the distribution condition of the 1st main component score and the 2nd main component score for every several types of recording media from which waste paper pulp content differs. It is a diagram which shows an example of the regression line obtained by the process by the regression line creation process execution part. It is a diagram which shows an example which calculated | required the used paper pulp content of the recording medium of a detection target using the regression line shown by the regression equation using the regression line. It is a flowchart which shows the content of the waste paper pulp content derivation | leading-out routine in the detection apparatus concerning this Embodiment. 1 is a schematic diagram illustrating an example of an image forming apparatus according to an exemplary embodiment. 4 is a flowchart illustrating processing executed by the image forming apparatus according to the present embodiment.

  Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.

As shown in FIG. 1, the detection apparatus 10 according to the present embodiment irradiates light in the near-infrared region (wave number band: 4000 cm ⁻¹ or more and 12500 cm ⁻¹ or less) to the recording medium. Measuring device 38 (details will be described later) for measuring the outer spectrum, input device 36 for inputting information indicating waste paper pulp content and various information, information indicating the near infrared spectrum input from the measuring device 38, and input device A computer 12 storing a derivation program for realizing a used paper pulp content derivation routine for deriving a used paper pulp content of a recording medium to be detected based on information indicating the used paper pulp content input from 36; And an output unit 34 for outputting a processing result in the computer 12.

  The measuring device 38 is a device using near infrared spectroscopy that measures the near infrared spectrum of the recording medium by irradiating the recording medium with light in the near infrared region. In near-infrared spectroscopy, forbidden transition is observed, so the absorbance is generally small. That is, near-infrared light is more likely to penetrate or penetrate into the sample to be measured (recording medium in this embodiment) than infrared light, ultraviolet light, and visible light. The material and state inside the recording medium to be measured are identified.

As the measuring device 38, a known device for measuring the near infrared spectrum may be used, and a dispersive near infrared spectrophotometer, a near infrared spectrophotometer using an optical filter, or a Fourier may be used. A conversion near infrared spectrophotometer may be used.
For example, when a Fourier transform type near-infrared spectrophotometer is used as the measuring device 38, a light source 39A, an interferometer 39B, a detector 39C, and an amplifier (illustrated) as in the measuring device 38A shown in FIG. (Omitted), and a configuration including a signal processing unit 39D and the like.
As the light source 39A, a light source that irradiates light in a wave number band in the near-infrared region (4000 cm ⁻¹ or more and 12500 cm ⁻¹ or less) is used. Specifically, examples of the light source 39A include a halogen lamp, a tungsten lamp, a xenon lamp, a light emitting diode, and a laser. Examples of the interferometer 39B include a Michelson interferometer, a intercept interferometer, and a polarization interferometer. As the detector 39C, in addition to a semiconductor detector (silicon, lead sulfide, indium / gallium / arsenic, indium / antimony, etc.), a photomultiplier tube is also used. In the signal processing unit 39D, the interference waveform detected by the detector 39C and amplified by an amplifier (not shown) is read into a near-infrared spectrum by Fourier transform. Then, information indicating the obtained near-infrared spectrum is output to the computer 12.

  In the measuring device 38, the position where the detector 39C is installed may be any position as long as it is a position other than the position where the measuring light to the recording medium is blocked. For this reason, as the measuring device 38, a method (so-called transmission method) in which the measuring light A transmitted through the recording medium 11 to be measured is detected by the detector 39C, as in the measuring device 38A shown in FIG. Or a method of detecting the measurement light A reflected from the inside of the recording medium to be measured by the detector 39C (so-called diffuse reflection method) as in the measurement device 38B shown in FIG. Or, an apparatus using an interaction method), or an apparatus using a method combining these (transmission reflection method) may be used.

  In addition, as a recording medium used for detection of used paper pulp content and a regression equation described later in the detection apparatus 10 of the present embodiment, non-coated printing paper, fine-coated printing paper, coated printing paper Printing paper such as special paper, copy (PPC) paper, information paper such as foam paper, coated paper for inkjet color printer, OCR paper, thermal paper, and the like.

  Virgin pulp contained in these recording media includes hardwood bleached kraft pulp (LBKP), softwood bleached kraft pulp (NBKP), hardwood unbleached kraft pulp (LUKP), softwood unbleached kraft pulp (NUKP), hardwood bleached Made by chemically treating wood and other fiber materials such as sulfite pulp (LBSP), softwood bleached sulfite pulp (LUSP), hardwood unbleached sulfite pulp (LUSP), softwood unbleached sulfite pulp (NUSP), soda pulp, etc. Pulp and the like.

In addition, waste paper pulp contained in these recording media includes trimmed paper, printing paper, cutting offices, etc., white paper, special white, medium white, white loss, etc. Waste paper pulp from which unprinted waste paper is dissociated, high quality paper, high quality coated paper, medium quality paper, medium quality coated paper, reprint paper, etc., lithographic, letterpress, letterpress printing, etc., electrophotographic method, thermal method, thermal transfer method And pressure-sensitive recording method, ink jet recording method, waste paper printed with carbon paper, and the like, and pulp obtained by dissociating water and oil-based inks and waste paper written with a pencil or the like after dissociation.

  Since near-infrared light is likely to pass through the recording medium, when measuring the near-infrared spectrum, it is possible to obtain more information inside the recording medium if these recording media are overlapped. More preferred. However, since the ease of transmission varies depending on the basis weight of the recording medium, the recording medium with a large basis weight may have little overlap, and may be appropriately selected according to the recording medium.

  The output unit 34 may be any device that outputs the result derived by the computer 12, and may be a known display device, printing device, external storage device, or external device such as a computer. The input device 36 may be any device that is operated by an operator when inputting various types of information. Examples of the input device 36 include, but are not limited to, a keyboard and a touch panel.

  The computer 12 includes a CPU (central processing unit), a ROM (read only memory) that stores a derivation program for realizing a waste paper pulp content derivation routine described later, a RAM (random access memory) that stores data, and the like. It is comprised including the bus which connects. When the computer 12 is described in terms of functional blocks divided for each function realizing means determined based on hardware and software, as shown in FIG. 1, the computer 12 executes a regression line creation process for calculating a regression equation described later. 12A and a used paper pulp content detecting unit 12B that detects a used paper pulp content of a recording medium to be detected.

  The regression line creation processing execution unit 12A includes a used paper pulp content acquisition unit 14, a near infrared spectrum acquisition unit 16A, a preprocessing unit 18A, a preprocessing result storage unit 20A, a principal component analysis unit 24, a principal component score calculation unit 26A, A regression equation calculation unit 28A and a regression equation storage unit 32A are included.

  First, before the process is performed by the regression line creation process execution unit 12A, the detection apparatus 10 of the present embodiment uses a plurality of types of recording media having different waste paper pulp contents for detection of regression equations (detection of the present invention). Corresponding to the first recording medium of the method). Note that the waste paper pulp content in the recording medium prepared during the regression line creation process is known in advance. In the present embodiment, the “waste paper pulp content” indicates the content (% by mass) of used paper pulp contained in 100% by mass of the pulp in the recording medium.

In addition, as the number (number of types) of a plurality of types of recording media having different waste paper pulp contents used for the regression equation creation, two or more types may be used, but from the viewpoint of creating a more accurate regression line. Three or more types are preferable, four or more types are more preferable, and the number of types is more preferable.
In addition, as a plurality of types of recording media having different waste paper pulp contents used for the regression equation creation, a recording medium having a waste paper pulp content of 0% by mass in the recording medium, and a content of 100% by mass. It is preferable to include at least a certain recording medium. As a plurality of types of recording media having different waste paper pulp contents used for regression formula creation, a recording medium having a waste paper pulp content of 0 mass% in the recording medium and a waste paper pulp content in the recording medium of 100 mass% When the recording medium is used at least, the difference in spectrum derived from the used paper pulp becomes remarkable, and the application range of the principal component analysis model is such that the used paper pulp content in the recording medium is between 0% by mass and 100% by mass. It will be applied to all areas. For this reason, it is thought that a more accurate regression equation (high detection accuracy of waste paper pulp content) can be obtained as a regression equation to be described later for obtaining the waste paper pulp content.

  The near-infrared spectrum acquisition unit 16A acquires the measurement result of the near-infrared spectrum input from the measuring device 38 for a plurality of types of recording media with known waste paper pulp content prepared for creating the regression equation. And output to the preprocessing unit 18A. The pre-processing unit 18A that has received the near-infrared spectrum from the near-infrared spectrum acquisition unit 16A performs pre-processing on the received near-infrared spectrum.

This pre-processing is a process performed to enhance the characteristics of the near-infrared spectrum or reduce the effects of spectrum complexity, absorption band overlap, etc. Shows mathematical preprocessing, such as normalization. As this preprocessing, multiple scattering correction (MSC) or standard normal variable (SNV) conversion may be used in combination.
In the present embodiment, as preprocessing in the preprocessing unit 18A, logarithmic spectrum calculation processing, first-order differentiation processing, and standard normal variate processing (SNV: Standard Normal Variate) are sequentially performed on the obtained near-infrared spectrum. Then, pre-processing is performed. When these pretreatments are performed in this order, it is considered that the effect of scattering can be suppressed as compared with the case where the pretreatment is not performed in the above order, and the effect that the variation of solids is reduced can be obtained.

  In the logarithmic spectrum calculation process, log (1 / R) may be obtained for the near-infrared spectrum R, or logR may be obtained. In such logarithmic spectrum calculation processing, small numerical values are emphasized with respect to large numerical values in the spectrum. Further, in the first-order differentiation process, the parallel movement effect in the vertical axis direction that does not depend on the wavelength is excluded, and the overlapping peaks are separated. Further, in the SNV process, the variation in the near infrared spectrum due to the solid is corrected.

For example, the following spectrum is obtained by performing the above-described preprocessing in the preprocessing unit 18A.
For example, as shown in FIG. 3, from the near-infrared spectrum acquisition unit 16A, a near-infrared spectrum 50A of a recording medium having a waste paper pulp content of 0% by mass and a near red of a recording medium having a waste paper pulp content of 50% by mass. Assume that an outer spectrum 50B and a near-infrared spectrum 50C of a recording medium having a waste paper pulp content of 100% by mass are obtained.
And about each of these near-infrared spectrum (50A, 50B, 50C), the calculation process (log (1 / R) (R: near-infrared spectrum)) of a logarithm spectrum as said pre-processing by the pre-processing part 18A By performing the first-order differentiation process and the standard normal variable process (SNV) in this order, the near-infrared spectra (51A, 51B, and FIG. 4C) shown in FIG. 4 (A), FIG. 4 (B), and FIG. 51C) is obtained.

  In the pre-processing result storage unit 20A, the near-infrared spectrum pre-processed by the pre-processing unit 18A is input by the input device 36 and acquired by the used paper pulp content acquisition unit 14 to indicate the used paper pulp content of the recording medium. It is stored in association with information. The information indicating the waste paper pulp content is input by the input device 36 by a user input operation or the like when reading the near-infrared spectrum by the measuring device 38 at the time of creating the regression equation, and used paper pulp content acquisition unit 14 It was acquired by. For this reason, the pre-processed near-infrared spectrum of the recording medium is associated with the information indicating the waste paper pulp content of the recording medium whose near-infrared spectrum is measured by the measuring device 38 in the pre-processing result storage unit 20A. Is remembered.

  Then, the same processing as described above is performed for a plurality of types of recording media having different waste paper pulp contents prepared for the regression equation creation, and the pretreatment result storage unit 20A has the prepared preparation for the regression equation. When the information indicating the waste paper pulp content and the near-infrared spectrum are stored for a plurality of types of recording media, the principal component analysis unit 24 performs principal component analysis.

  In the principal component analysis unit 24, the principal components of the near-infrared wave number bands other than the excluded wave number band in the near-infrared spectra of a plurality of types of recording media having different waste paper pulp contents stored in the preprocessing result storage unit 20 </ b> A Perform analysis and create a principal component analysis model. The principal component analysis model is a mathematical formula for deriving a principal component score of each of a plurality of principal components described later from a near-infrared spectrum. Information indicating the excluded wave number band is stored in advance in a storage unit 25 provided in the principal component analysis unit 24. The excluded wave number band corresponds to the first wave number band in the method for detecting waste paper pulp content of the present invention.

The excluded wave number band is a wave number band to be excluded from the principal component analysis target when performing the principal component analysis of the near infrared spectrum in the detection apparatus 10 of the present embodiment. And a wave number band corresponding to a region where an absorption peak due to stretching vibration of oxygen atoms and hydrogen atoms (OH-stretching vibration of a hydroxyl group) appears. Examples of the excluded wave number band include a wave number band in which a sharp absorption peak due to the stretching movement of OH of a hydrogen-bonded OH group in a filler, an internal additive, or the like contained in a recording medium appears. Specifically, it is preferable that the frequency band and 7020cm ^-1 or 7280cm ^-1 the following frequency band of 4500cm ^-1 or 4600cm ^-1 or less.

In the principal component analysis unit 24, the excluded wave number band (4500 cm ⁻ ) in the near infrared wave number band (4000 cm ^{−1 to} 12500 cm ⁻¹ or less) of the near infrared spectra of a plurality of types of recording media having different waste paper pulp contents is used. by ^one or more 4600Cm ^-1 to perform a principal component analysis of the following frequency band and 7020cm ^-1 or 7280cm ^-1 the following frequency band) than the frequency band, the main component such as heaven fees or adductor chemicals contained in the recording medium The influence on the calculation at the time of analysis is excluded.

As the above-mentioned exclusion frequency band, 4190cm ^-1 or 4270cm ^-1 The following frequency band, 4500cm ^-1 or 4670cm ^-1 The following frequency band, 4900cm ^-1 or 5360cm ^-1 The following frequency band, and 7000 cm ^-1 or more A wave number band of 7300 cm ⁻¹ or less is more preferable. These excluded wavenumber bands are attributed to the stretching motion of OH that appears due to the influence of environmental humidity and paper moisture in addition to the wavenumber band in which a sharp absorption peak appears due to the stretching motion of OH of the hydrogen-bonded OH group. This is more preferable because the influence of a broad absorption peak derived from other vibrations overlapping the wave number band where the absorption peak appears and the wave number band where the absorption peak appears due to the stretching motion of the OH is excluded.

Furthermore, as the excluded wave number band, it is more preferable to add a wave number band of 10000 cm ^{−1 to} 12500 cm ⁻¹ to the excluded wave number band in addition to the above-described wave number bands. This absorption peak of 10000 cm ^-1 or higher 12500Cm ^-1 less frequency band, since it is often contains noise, it is preferable to exclude the time principal component analysis.

  In addition, by providing the above-described excluded wave number band at the time of principal component analysis, the information amount of the near-infrared spectrum for performing principal component analysis is reduced, but as described above, the detection apparatus 10 of the present embodiment. In the principal component analysis, the principal component analysis is performed on the near-infrared wave number band other than the excluded wave number band in the near-infrared spectrum of the recording medium, and as a result, a more accurate regression equation (regression line, details will be described later). ) And the content of used paper pulp in the recording medium is detected with higher accuracy.

  Here, principal component analysis is a method for creating multi-variate data to create a new comprehensive index, and is a method for creating a small number of synthetic variables by adding weights to many variables. In the calculation of the weight, eigenvalue expansion is used so that as many synthetic variables as possible contain the information amount of the original variables.

  Next, a method for performing principal component analysis on the near-infrared wavenumber bands other than the excluded wavenumber band in the near-infrared spectra of a plurality of types of recording media having different waste paper pulp contents in the present embodiment will be specifically described. explain.

First, the correlation matrix (in the near-infrared spectra of a plurality of types of recording media having different waste paper pulp contents obtained and pre-processed by the above processing, as sampling data, each of the spectrums in the wave number bands other than the excluded wavelength band are used as sampling data. For example, an M × N or M × M correlation matrix (M ≧ N) is calculated, and the correlation matrix is expanded into eigenvalues to calculate eigenvalues and eigenvectors. Then, the eigenvectors are arranged in descending order of the eigenvalues, and the first principal component, the second principal component,..., The Nth principal component are arranged in order from the eigenvector corresponding to the large eigenvalue.
Here, since each sampling data is a near-infrared spectrum of a plurality of types of recording media having different waste paper pulp contents (however, a spectrum excluding the above-described excluded wave number band), the difference in the waste paper pulp content is the sampling data. The first main component is a component that depends on the content of waste paper pulp contained in the recording medium.

Therefore, in the principal component score calculation unit 26A, each of the spectra other than the excluded wave number band of the near-infrared spectrum of a plurality of types of recording media having different waste paper pulp contents analyzed by the principal component analysis unit 24 is used. Of the principal component analysis results, the principal component score of the first principal component is calculated.
For this reason, the principal component score calculation unit 26A calculates the principal component scores of the first principal component for a plurality of types of recording media having different waste paper pulp contents prepared for creating regression equations.

  The calculation of the principal component score is obtained by reading the score obtained by projection onto the axis (vector) corresponding to the first principal component obtained in the principal component analysis in the principal component analysis unit 24.

For example, from the near-infrared spectrum acquisition unit 16A, a near-infrared spectrum 50A of a recording medium having a waste paper pulp content of 0% by mass, a near-infrared spectrum 50B of a recording medium having a waste paper pulp content of 50% by mass, and a waste paper pulp content Assume that the near-infrared spectrum (50A, 50B, 50C) shown in FIG. Then, after the preprocessing is performed by the preprocessing unit 18A, the principal component analysis is performed by the principal component analysis unit 24, and the principal component scores when the principal component scores are calculated by the principal component score calculation unit 26A. An example of the calculation result is shown in FIG.
In FIG. 5, the X-axis represents the first principal component score, and the Y-axis represents the second principal component score. In FIG. 5, the distribution state of the first main component score and the second main component score of the recording medium having a waste paper pulp content of 0% by mass is indicated by a plot 52CA, and the first recording medium having a waste paper pulp content of 50% by mass is shown in the plot 52CA. The distribution status of the main component score and the second main component score is shown by a plot 52B, and the distribution status of the first main component score and the second main component score of the recording medium having a waste paper pulp content of 100% by mass is shown by the plot 52C.

The regression equation calculation unit 28A performs regression analysis based on the correlation between the principal component score calculated by the principal component score calculation unit 26A and the waste paper pulp content of the recording medium corresponding to the principal component score, and the regression Calculate the formula.
Specifically, as shown in FIG. 6, the regression equation is obtained by the principal component score calculation unit 26A, with the waste paper pulp content on the horizontal axis and the principal component score of the first principal component on the vertical axis. Each of the positions corresponding to the main component score and the waste paper pulp content is plotted (see plots 54A, 54B, and 54C in FIG. 6), and the sum of the distances from these plots to the regression line L is minimized. It can be obtained by calculating a simple regression equation. In the present embodiment, as shown in FIG. 6, a case is described in which a regression equation indicated by a curved regression line L (that is, a regression line of a polynomial) is obtained, but depending on the type of recording medium, A curved regression line is not always obtained, and a linear regression line may be obtained.

  In the regression equation storage unit 32A, the regression equation obtained from the correlation between the waste paper pulp content calculated by the regression equation calculation unit 28A and the first principal component score is stored.

  As described above, the regression equation (regression line) is a main component score of the first main component obtained from a recording medium having a different waste paper pulp content used for the regression equation creation, a waste paper pulp content, As described above, the number of types of recording media with different waste paper pulp content (number of types) used to create this regression equation increases the number of types of waste paper pulp content to be detected. The detection accuracy of waste paper pulp content in the recording medium is improved.

  Next, the used paper pulp content detection unit 12B included in the computer 12 will be described.

The used paper pulp content detection unit 12B is a functional unit that detects the used paper pulp content of the recording medium to be detected using the regression line created by the regression line creation processing execution unit 12A.
Specifically, as shown in FIG. 1, the used paper pulp content detection unit 12B includes a near-infrared spectrum acquisition unit 16B, a preprocessing unit 18B, a preprocessing result storage unit 20B, a principal component analysis unit 24, a principal component score. The calculation unit 26B and the used paper pulp content deriving unit 30B are included.

  The near-infrared spectrum acquisition unit 16B acquires the near-infrared spectrum of the recording medium whose waste paper pulp content is to be detected from the measurement device 38 in the same manner as the near-infrared spectrum acquisition unit 16A. Note that the difference from the near-infrared spectrum acquisition unit 16A is that the obtained recording medium showing the near-infrared spectrum is a recording medium whose waste paper pulp content is detected and whose used paper pulp content is unknown. is there.

  In the preprocessing unit 18B, preprocessing is performed on the near-infrared spectrum of the recording medium to be detected acquired by the near-infrared spectrum acquisition unit 16B in the same manner as the preprocessing unit 18A. This preprocessing result is stored in the preprocessing result storage unit 20B. In the principal component analysis unit 24, the plurality of types of first recording media stored in the preprocessing result storage unit 20A for the preprocessed near-infrared spectrum stored in the preprocessing result storage unit 20B. A comparison is made with each of the near infrared spectra. And, based on the principal component analysis model created by the principal component analysis unit 24 in the process in the regression line creation processing execution unit 12A, for the pre-processed near infrared spectrum stored in the preprocessing result storage unit 20B, A principal component score for the first principal component of the plurality of principal components is computed by the principal component score computation unit 26B.

The waste paper pulp content deriving unit 30B uses the regression equation stored in the regression equation storage unit 32A by the processing of the regression line creation processing execution unit 12A to detect the recording medium to be detected calculated by the principal component score calculation unit 26B. The waste paper pulp content is derived from the main component score of.
For example, when the regression equation indicated by the regression line L shown in FIGS. 6 and 7 is stored in the regression equation storage unit 32A, the regression equation is used to calculate the principal component score calculation unit 26B. By determining the waste paper pulp content corresponding to the main component score of the first main component, the waste paper pulp content of the recording medium to be detected is easily determined.

  Next, a waste paper pulp content deriving routine according to the present embodiment performed by the computer 12 will be described with reference to FIG.

  First, in step 100, it is determined whether or not the regression line creation processing execution unit 12A is in the regression equation creation mode in which processing is executed. In step 100, for example, an operation unit (not shown) is provided in the detection device 10 and connected to the computer 12 so that signals can be transmitted and received. The operation unit (not shown) is operated by an operator, This is done by determining that a signal indicating the regression equation creation mode has been input.

  If the determination in step 100 is affirmative, the process proceeds to step 102, and negative determination is repeated until information indicating the waste paper pulp content is acquired from the input device 36. If the determination is affirmative, the process proceeds to step 104, and the acquired waste paper pulp content is indicated. Information is stored in the preprocessing result storage unit 20A.

  In the next step 106, the near-infrared spectrum of the recording medium to which the information indicating the waste paper pulp content is input in step 102 is acquired from the measuring device 38. Then, in the next step 108, preprocessing is performed on the acquired near-infrared spectrum. In the next step 110, the near-infrared spectrum preprocessed in step 108 is associated with information indicating the waste paper pulp content stored in the preprocess result storage unit 20 </ b> A in step 104, and the preprocess result storage unit Store in 20A.

In the next step 112, it is determined whether or not the processing in steps 102 to 110 has been performed N times, which is a predetermined number. If the determination is negative, the processing returns to step 102, and the processing in steps 102 to 102 is repeated until affirmative. The process of step 112 is repeated. Note that the N times indicates the number (number of types) of a plurality of types of recording media having different waste paper pulp contents, which is used for creating a regression line, and may be stored in advance. For example, when the number of types of recording media with different waste paper pulp contents used for creating the regression line is 4, the value indicating 4 may be stored in advance as N times.
The number N of times may be rewritable at any time by operating an operation unit (not shown). However, as described above, it is preferable that the number of types of recording media used for creating the regression line is two or more. Therefore, the number N may be determined in advance and stored in correspondence with the number of types.

  If affirmative in step 112, the process proceeds to step 114, where the principal component analysis described above is performed for wavebands other than the excluded wavebands described above for the near-infrared spectrum of the recording medium whose wastepaper pulp content is known. Create an analytical model. In the next step 116, the principal component score for the first principal component is calculated for each of the plurality of types of recording media. In the next step 118, the regression equation is calculated based on the principal component score obtained in step 116. calculate. In the next step 120, the regression equation calculated in step 118 is stored in the regression equation storage unit 32A, and then this routine is terminated.

  That is, by performing the processing of step 100 to step 120, the processing performed by the above-described regression line creation processing execution unit 12A is performed, and the regression equation is obtained and stored in the regression equation storage unit 32A.

  On the other hand, if the result in Step 100 is negative, the routine proceeds to Step 122, where it is determined whether or not it is a used paper pulp content detection mode in which processing is performed in the used paper pulp content detection unit 12B. The determination in step 122 is performed by, for example, providing an operation unit (not shown) in the detection device 10 and connecting it to the computer 12 so as to be able to send and receive signals. This is performed by determining that a signal indicating that the waste paper pulp content calculation mode has been input.

  If the result in step 122 is negative, the routine is terminated. If the result in step 122 is affirmative, the routine proceeds to step 124.

  In step 122, a near-infrared spectrum is acquired from the measuring device 38 for the recording medium whose target is the waste paper pulp content. Then, in the next step 126, preprocessing is performed on the acquired near-infrared spectrum. In the next step 127, the near-infrared spectrum preprocessed in step 126 is stored in the preprocess result storage unit 20B.

  In the next step 128, a principal component score for the first principal component is calculated from the preprocessed near-infrared spectrum stored in the preprocessing result storage unit 20B in step 127. In the next step 132, the main equation calculated in step 130 is calculated using the regression equation stored in the regression equation storage unit 32A by the processing in step 120 in the above-described regression line creation processing (step 100 to step 120). The waste paper pulp content corresponding to the component score is derived. Through the processing of step 134, the waste paper pulp content of the recording medium to be detected is detected.

  In the next step 136, the derivation result in step 134 is output to the output unit 34, and then this routine is terminated.

  As described above, in the detection apparatus 10 of the present embodiment, during the principal component analysis, the principal component analysis of the near infrared region other than the above-described excluded wave number band is performed on the near infrared spectrum, and the analysis result is obtained. Since the generation of the regression line and the derivation of the used paper pulp content are performed, the used paper pulp content is detected with high accuracy.

(Image forming device)
The detection device 10 of the present embodiment described above may be mounted on an image forming apparatus.
FIG. 9 shows an example of the configuration of a so-called tandem type image forming apparatus as an example of an image forming apparatus equipped with the detection device 10 of the present embodiment. I can't.

  An image forming apparatus 200 shown in FIG. 9 is arranged around four image holding members 201a to 201d formed of an electrophotographic photosensitive member in order along the rotation direction, in order of charging devices 202a to 202d, exposure devices 214a to 214d, Developing devices 203a to 203d, primary transfer devices (primary transfer rolls) 105a to 105d, and image carrier cleaning devices 204a to 204d are arranged.

  The intermediate transfer belt 207 includes a tension roll 206a as a member for applying tension, fixed rolls 206b and 206c, a drive roll 212 as a member for driving the intermediate transfer belt 207, and the intermediate transfer belt 207 at the secondary transfer position. It is stretched around a back roll 208 as a supporting member.

  In the following description, when the stretching roll 206a, the fixed rolls 206b and 206c, the secondary transfer roll 209, and the back roll 208 that convey the intermediate transfer belt 207 are collectively referred to as a stretching roll 221 There is.

  The plurality of stretching rolls 221 are configured in a columnar shape. The tension roll 206a and the back roll 208 are driven and rotated by the drive roll 212 being driven to rotate about the axial direction as a rotation axis by a drive unit (not shown). The intermediate transfer belt 207 is conveyed in the circumferential direction (in the direction of arrow A in FIG. 9, that is, the conveyance direction) by being conveyed by these stretching rolls, drive rolls 212, and back rolls 208.

  The primary transfer rolls 205a to 205d are disposed in contact with the inner peripheral surface side of the intermediate transfer belt 207 so as to sandwich the intermediate transfer belt 207 between each of the image carriers 201a to 201d. A region between each of the primary transfer rolls 205a to 205d and each of the image carriers 201a to 201d is a primary transfer region. A primary transfer current is applied to each of the primary transfer regions by each of the primary transfer rolls 205a to 205d, whereby the toner image held on each of the image holders 201a to 201d is transferred to the intermediate transfer belt 207. Transcribed above. Further, in the image forming apparatus 200, a back roll 208 and a secondary transfer roll 209 are disposed to face each other via an intermediate transfer belt 207 and a secondary transfer belt 216. The secondary transfer belt 216 is conveyed by a secondary transfer roll 209 and a roll 206d. An area where the secondary transfer roll 209 contacts the back roll 208 via the intermediate transfer belt 207 and the secondary transfer belt 216 becomes a secondary transfer area, and a contact portion between the secondary transfer roll 209 and the back roll 208 does not have a secondary transfer area. A next transfer voltage is applied.

  A recording medium 215 such as paper is disposed in the paper feed tray 213, and is transported from the paper feed tray 213 to the transport path by the transport roller 217, the transport roller 218, and the transport roller 219 to the secondary transfer region. It is conveyed. The recording medium 215 conveyed to the secondary transfer region is conveyed in the direction of arrow B between the intermediate transfer belt 207 and the secondary transfer roll 209 while contacting the surface of the intermediate transfer belt 207, and then the fixing device. Pass 210. As a result, the toner image held on the intermediate transfer belt 207 is transferred to the recording medium 215, and the toner image is fixed on the recording medium 215 by the fixing device 210.

  The image forming apparatus 200 is further provided with an intermediate transfer belt cleaning device 211 so as to come into contact with the intermediate transfer belt 207 after transfer, and foreign matters such as toner and paper dust on the intermediate transfer belt 207 are removed. The

  The image forming apparatus 200 having the above configuration is provided with a control unit 220 that controls each part of the apparatus, and this control part 220 is connected to each part of the apparatus so as to be able to exchange signals.

  The image forming apparatus 200 is provided with a detection device 10. The detection device 10 may be configured such that the measurement device 38 in the detection device 10 is provided at a position where the near-infrared spectrum of the recording medium 215 before the toner image is transferred can be measured. For example, a configuration in which the detection device 10 is provided at a position (see FIG. 9) where the near-infrared spectrum of the recording medium that has been transported from the paper feed tray 213 to the transport path and before the toner image is transferred can be measured. And it is sufficient. Further, for example, the measurement device 38 in the detection device 10 may be provided on the paper feed tray 213.

  The computer 12 of the detection apparatus 10 may be configured to be connected to the control unit 220 of the image forming apparatus 200 so as to be able to exchange signals. Specifically, instead of the output unit 34 shown in FIG. 1, the control unit 220 of the image forming apparatus 200 may be connected to the used paper pulp content deriving unit 30B so as to be able to exchange signals. In addition, a signal line connected to the input device 36 and an operation unit (not shown) may be electrically connected to the control unit 220 of the image forming apparatus 200.

  Next, an example of processing executed by the control unit 220 of the image forming apparatus 200 will be described with reference to FIG.

  As shown in FIG. 10, in step 300, waste paper pulp content derivation processing is executed. The process of step 300 is a process of outputting a signal indicating the waste paper pulp content detection mode to the computer 12 of the detection apparatus 10.

In the detection apparatus 10, the processing in the regression line creation processing execution unit 12A described above, which is indicated by the above steps 100 to 120, is executed in advance, and the regression equation is already created and stored in the regression equation storage unit 32A. It shall be.
When the detection apparatus 10 is mounted on the image forming apparatus 200, the control unit 220 determines whether or not the used paper pulp content detection mode in step 122 described above is performed by the computer 12 of the detection apparatus 10. The determination may be made by determining whether or not a signal indicating the pulp content detection mode is input.

  In the next step 302, the negative determination is repeated until information indicating the used paper pulp content is acquired from the detection apparatus 10. If the determination is affirmative, the process proceeds to step 304. In this step 302, for example, when the detection apparatus 10 is mounted on the image forming apparatus 200, the output destination of the waste paper pulp content in the process of step 136 described above performed by the computer 12 of the detection apparatus 10 is output. The control unit 220 may be used instead of the unit 34.

  In the next step 304, an image forming condition for performing an image forming process for forming an image based on the image data is set on the recording medium having the used paper pulp content acquired in the above step 302.

  As the image forming conditions, information indicating the image forming conditions corresponding to the information indicating the waste paper pulp content of the image recording target recording medium is stored in advance in the storage unit 220A provided in the control unit 220. The information indicating the image forming conditions corresponding to the information indicating the waste paper pulp content acquired in step 302 is read, and the read image forming conditions are set.

  Examples of the image forming conditions include fixing conditions and transfer conditions. Examples of the fixing conditions include a fixing temperature in the fixing device 210, a fixing speed in the fixing device 210, and a pressure at the time of fixing in the fixing device (pressure applied to the recording medium at the time of fixing). The transfer conditions include a transfer current value, a transfer voltage value, and a transfer pressure at the time of transferring a toner image to a recording medium, that is, at the time of secondary transfer by the back roll 208 and the secondary transfer roll 209. .

Specifically, these image forming conditions are the above-mentioned fixing conditions and transfer conditions for forming an image on a recording medium having a specific used paper pulp content (hereinafter referred to as a reference content) as a reference in advance. It is set as a standard condition. As the waste paper pulp content in the recording medium acquired in step 202 becomes larger than the reference content, the above-described fixing temperature, fixing pressure, transfer current value, transfer voltage value, and transfer pressure pressure are increased. Values for adjusting these conditions may be determined in advance so that at least one of them becomes large (high), and may be stored in advance in association with information indicating the content of waste paper pulp.
Similarly, as the waste paper pulp content in the recording medium acquired in step 302 is smaller than the reference content, the above-described fixing temperature, fixing pressure, transfer current value, transfer voltage value, and transfer time are transferred. Values for adjusting these conditions may be determined in advance so that at least one of the pressures is small (lower), and stored in advance in association with information indicating the content of waste paper pulp.

  In the next step 306, after performing an image forming process for forming an image on a recording medium under the image forming conditions set in step 304, this routine is terminated. The processing in steps 300 to 306 is executed for each recording medium on which an image is to be formed in the image forming apparatus 200.

  Note that as the content of used paper pulp contained in the recording medium increases, the strength of the recording medium decreases and the curl (warp) occurs. In addition, as the content of used paper pulp contained in the recording medium increases, streaky image defects and paper feed defects are more likely to occur due to the generation of paper dust. For this reason, the image forming apparatus 200 equipped with the detection device 10 is used, and by performing the processing of the above steps 302 to 306, the optimum image formation is performed according to the waste paper pulp content contained in the recording medium to be image formed. Image formation is performed under conditions. For this reason, it is considered that the image quality of the image recorded on the recording medium can be improved without depending on the waste paper pulp content contained in the recording medium.

<< Test Example >>

  Hereinafter, the present invention will be described in more detail with reference to test examples, but the present invention is not limited to the following test examples.

(Test Example 1)
A near-infrared analyzer NIRFLEX N-500 (manufactured by Nihon Büch Co., Ltd.) was prepared as a measuring device (see measuring device 38 in FIG. 1) for measuring the near-infrared spectrum of the recording medium. Further, the measuring apparatus is electrically connected to the computer 12 described above, the derivation program is stored, and the used paper pulp content derivation for deriving the used paper pulp content of the recording medium to be detected by the derivation program. A test detector was developed to execute the routine.

  Next, as a recording medium for creating a regression line, advanced printing paper with a waste paper pulp content of 0% by mass (trade name Able CoC, manufactured by Heiwa Paper Industry Co., Ltd.) and advanced printing paper with a waste paper pulp content of 50% by mass (ideal Prepared by Kagaku Kogyo Co., Ltd., trade name RG environmental paper ideal friend II), and advanced printing paper (Oji Paper Co., Ltd., trade name OK Prince Fine Eco G100) with a waste paper pulp content of 100% by mass, Using the test detection apparatus, the regression line creation processing execution unit 12A executed the regression equation creation processing (the processing from step 100 to step 120).

The excluded wavelength band was the excluded wavelength band shown in A below. Moreover, the near-infrared region in the near-infrared spectrum was set to a wave number band of 4000 cm ⁻¹ or more and 10,000 cm ⁻¹ or less. In addition, the number of overlapping recording media was set to 1 when creating the regression equation and measuring the content of waste paper pulp.

  Further, as a calculation method at the time of preprocessing, a calculation method X at the time of preprocessing shown below was used.

<Excluded wavenumber band>
Excluded wavenumber band A: 4550 ± 50 cm ⁻¹ and 7150 ± 130 cm ⁻¹
Excluded wavenumber band B: 4230 ± 40 cm ⁻¹ , 4585 ± 85 cm ⁻¹ , 5130 ± 230 cm ⁻¹ , and 7150 ± 150 cm ⁻¹
Excluded wavenumber band C: 4230 ± 100 cm ⁻¹ , 4585 ± 85 cm ⁻¹ , 5130 ± 230 cm ⁻¹ , and 7150 ± 150 cm ⁻¹
Excluded wavenumber band D: 4230 ± 40 cm ⁻¹ , 4585 ± 150 cm ⁻¹ , 5130 ± 230 cm ⁻¹ , and 7150 ± 150 cm ⁻¹
Excluded wavenumber band E: 4230 ± 40 cm ⁻¹ , 4585 ± 85 cm ⁻¹ , 5130 ± 300 cm ⁻¹ , and 7150 ± 150 cm ⁻¹
Excluded wavenumber band F: 4230 ± 40 cm ⁻¹ , 4585 ± 85 cm ⁻¹ , 5130 ± 300 cm ⁻¹ , and 7150 ± 150 cm ⁻¹
Excluded wavenumber band G: 4200 ± 40 cm ⁻¹ , 4585 ± 85 cm ⁻¹ , 5130 ± 230 cm ⁻¹ , and 7150 ± 150 cm ⁻¹
Excluded wavenumber band H: 4230 ± 20 cm ⁻¹ , 4585 ± 85 cm ⁻¹ , 5130 ± 230 cm ⁻¹ , and 7150 ± 150 cm ⁻¹
Excluded wavenumber band I: 4230 ± 40 cm ⁻¹ , 4530 ± 85 cm ⁻¹ , 5130 ± 230 cm ⁻¹ , and 7150 ± 150 cm ⁻¹
Excluded wave number band J: 4230 ± 40 cm ⁻¹ , 4585 ± 30 cm ⁻¹ , 5130 ± 230 cm ⁻¹ , and 7150 ± 150 cm ⁻¹
Excluded wavenumber bands K: 4230 ± 40 cm ⁻¹ , 4585 ± 85 cm ⁻¹ , 5000 ± 230 cm ⁻¹ , and 7150 ± 150 cm ⁻¹
Excluded wavenumber band L: 4230 ± 40 cm ⁻¹ , 4585 ± 85 cm ⁻¹ , 5130 ± 100 cm ⁻¹ , and 7150 ± 150 cm ⁻¹
Excluded wavenumber band M: 4230 ± 40 cm ⁻¹ , 4585 ± 85 cm ⁻¹ , 5130 ± 230 cm ⁻¹ , and 7050 ± 150 cm ⁻¹
Excluded wavenumber bands N: 4230 ± 40 cm ⁻¹ , 4585 ± 85 cm ⁻¹ , 5130 ± 230 cm ⁻¹ , and 7150 ± 50 cm ⁻¹
Excluded wave number band O: Wave number band of 4000 cm ⁻¹ or more and 10000 cm ⁻¹ or less

―Evaluation―
Next, as a recording medium for detecting waste paper pulp content, high-grade printing paper (product name: environmental paper 64gRJ64FSC-A0R manufactured by Musashi Kogyo Co., Ltd.) having a waste paper pulp content of 25% by weight, and a waste paper pulp content of 50% by weight. Advanced printing paper (made by Riso Kagaku Kogyo Co., Ltd., trade name RG environmental paper ideal friend II) and advanced printing paper with 70% by weight waste paper pulp content (made by Riso Kagaku Kogyo Co., Ltd., trade name ideal environmental paper NW) Each of these recording media was prepared, and the processing by the used paper pulp content detection unit 12B was executed using the test detection device, and the used paper pulp content in these recording media was detected.

  And the accuracy with respect to actual waste paper pulp content is calculated | required about the detection result of the waste paper pulp content of the recording medium of detection object of each of these waste paper pulp content of 25 mass%, 50 mass%, and 70 mass%. It was. The evaluation criteria are as follows, and the evaluation results are shown in Table 1.

--Evaluation criteria--
A: When the value of the detected waste paper pulp content with respect to the actual waste paper pulp content is within ± 5% by mass.
○: When the value of the detected waste paper pulp content with respect to the actual waste paper pulp content is within an error of ± 10% by mass.
(Triangle | delta): When the value of the detected waste paper pulp content with respect to actual waste paper pulp content is an error within +/- 15 mass%.
X: When the value of the detected waste paper pulp content with respect to the actual waste paper pulp content is an error larger than ± 15% by mass.

(Test Example 2 to Test Example 20, Comparative Test Example 1 to Comparative Test Example 18)
In Test Example 1 above, the number of recording media used when creating the regression equation, the type of excluded wave number band during principal component analysis, the type of recording medium, the number of overlapping recording media during near-infrared spectrum measurement, and preprocessing Except that the calculation method at the time was changed to the one shown in Table 1, a regression equation was created in the same manner as in Test Example 1, and the waste paper pulp content was 20% by mass and 50% by mass in the same manner as in the Test Example. The accuracy of the waste paper pulp content measured using a test detector for each of the recording media to be detected for 70% by mass and 70% by mass with respect to the actual waste paper pulp content was determined by the following equation. The evaluation criteria are as follows, and the evaluation results are shown in Table 1.

  In Table 1, PPC paper is recycled PPC paper (manufactured by Fuji Xerox Interfield), and PPC paper having a waste paper pulp content of 0% by mass is Fuji Xerox Interfield, trade name P paper. Used, as a PPC paper having a waste paper pulp content of 50% by mass, manufactured by Fuji Xerox Interfield, Inc., using the product name SG, and as a PPC paper having a used paper pulp content of 100% by mass, manufactured by Fuji Xerox Interfield, Inc., having a product name of GR100. Using.

  In Table 1, in Test Example 3 and Test Example 4, the number of recording media used for creating the regression equation is two. In Test Example 3 and Test Example 4, the recording medium for creating the regression equation is used. High-quality printing paper with a waste paper pulp content of 0% by mass (trade name: Able CoC, manufactured by Heiwa Paper Industry Co., Ltd.) and high-grade printing paper with a waste paper pulp content of 100% by weight (trade name: OK Prince, fine quality) Eco G100) was used.

  As shown in Table 1, in the apparatus in this test example, the waste paper pulp content in the recording medium was obtained with higher accuracy than in the comparative test example.

DESCRIPTION OF SYMBOLS 10 Detection apparatus, 14 Waste paper pulp content acquisition part, 16A, 16B Near infrared spectrum acquisition part, 18A, 18B Pre-processing part, 20A, 20B Pre-processing result storage part, 24 Principal component analysis part, 26A, 26B Principal component score Calculation unit, 28A regression equation calculation unit, 30B waste paper pulp content derivation unit, 32A regression equation storage unit, 38 measuring device, 200 image forming device

Claims (5)

Transfer means for transferring a toner image on the photoreceptor onto a recording medium;
Fixing means for fixing the transferred toner image to the recording medium;
Detecting means for detecting the waste paper pulp content of the recording medium based on the near-infrared spectrum of the recording medium measured before transfer by the transfer means;
A control unit that increases at least one of a transfer current, a transfer voltage, and a fixing temperature of the fixing unit as the waste paper pulp content detected by the detecting unit increases.
An image forming apparatus comprising :
The detection means includes
A first infrared image acquisition unit that obtains near-infrared spectra of a plurality of types of first recording media having different waste paper pulp contents and content data indicating the waste paper pulp content of each of the plurality of types of first recording media. Acquisition means;
Wave numbers other than the first wave number band corresponding to absorption by stretching vibration of oxygen atoms and hydrogen atoms in the near-infrared spectrum of each of the plurality of types of first recording media acquired by the first acquisition unit. First principal component analysis means for performing principal component analysis on the band and creating a principal component analysis model;
First computing means for computing a principal component score for the first principal component of the plurality of principal components obtained by the first principal component analyzing means for each of the plurality of types of first recording media;
The main component score of each of the plurality of types of first recording media calculated by the first calculation means, and the inclusion of each of the plurality of types of first recording media acquired by the first acquisition means. A regression equation calculation means for performing a regression analysis based on the correlation with the quantity data and calculating a regression equation;
Second acquisition means for measuring and acquiring a near-infrared spectrum of a second recording medium that is a detection target of waste paper pulp content conveyed from the paper feed tray between the paper feed tray and the transfer means. When,
Compare the near-infrared spectrum of the second recording medium acquired by the second acquisition means with the near-infrared spectrum of each of the plurality of types of first recording media acquired by the first acquisition step. And a second calculation means for calculating a principal component score for the first principal component of the plurality of principal components based on the principal component analysis model created by the first principal component analysis means;
Using the regression equation calculated by the regression equation calculation means, the waste paper pulp content of the second recording medium is derived by deriving the waste paper pulp content corresponding to the main component score obtained by the second calculation means. Detection means for detecting the content;
An image forming apparatus. It said first frequency band is, 4500cm ^-1 or 4600cm ^-1 The following frequency band, and an image forming apparatus according to claim 1 7020Cm ^-1 or 7280cm ^-1 are the following frequency band. It said first frequency band is, 4190cm ^-1 or 4270cm ^-1 The following frequency band, 4500cm ^-1 or 4670cm ^-1 The following frequency band, 4900cm ^-1 or 5360cm ^-1 The following frequency band, 7000 cm ^-1 or more 7300Cm ^- The image forming apparatus according to claim 2 , wherein the image forming apparatus has a wave number band of ¹ or less. The control means includes
At least one of the fixing temperature, fixing speed, and fixing pressure in the fixing unit is set to a predetermined value corresponding to the waste paper pulp content detected by the detecting unit. The image forming apparatus according to any one of claims 1 to 3 . The control means includes
At least one of the transfer current, the transfer voltage, and the transfer pressure in the transfer unit is set to a predetermined value corresponding to the waste paper pulp content detected by the detection unit. the image forming apparatus according to any one of claims 1 to 4, characterized.

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