JP2013101412A - Measuring apparatus and measuring method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To more accurately measure a toner amount on a patch having a fine pattern.SOLUTION: Light is projected on a carrier or transfer part surface, and a toner patch surface on a carrier or transfer part. The light reflected by the carrier or transfer part surface, and the toner patch surface on the carrier or transfer part is received, and intensity distributions at the light reception position of the received light are measured. The toner amount on the toner patch is calculated from a difference between a feature quantity of a waveform of the measured intensity distribution from the carrier or transfer part surface and a feature quantity of a waveform of the measured intensity distribution from the toner patch surface on the transfer part. Based upon a timing signal corresponding to position information on the toner patch on the carrier or transfer part from a control part, light having first intensity is projected on the carrier or transfer part surface, and light having second intensity lower than the first intensity is projected on the toner patch surface on the carrier or transfer part.

Description

  The present invention relates to a technique for measuring the amount of toner on a medium.

  The color output by the image forming apparatus using toner varies depending on the environment. For example, when the temperature / humidity changes, the latent image potential, the toner replenishment amount, the transfer efficiency, and the like also change. Thus, the amount of toner adhering to the photosensitive drum and the transfer belt is not constant. Therefore, conventionally, a technique for controlling the exposure amount, the development voltage, the transfer current, and the like based on the measured toner adhesion amount has been developed. For example, according to the method described in Patent Document 1, light is projected onto a patch formed based on patch data. By detecting the light reflected by the patch, the toner amount can be measured.

  Patent Document 2 discloses an optical displacement meter. The optical displacement meter of Patent Document 2 feedback-controls the intensity of incident light so that the intensity of reflected light is appropriate. If the intensity of the reflected light is too weak, accurate measurement is difficult. If the intensity of the reflected light is too strong, the measurement value output from the light receiving unit is saturated. In order to cope with these problems, Patent Document 2 uses feedback control.

JP-A-8-327331 JP 2008-216600 A

  The amount of adhering toner differs between a black solid patch and a patch formed using screen technology (including halftone technology and dithering technology). Therefore, in order to appropriately control the formation of an image using the screen, it is necessary to measure the toner amount of the patch formed using the screen. However, a patch formed using a screen contains a portion where toner is attached and a portion where the medium is exposed. Furthermore, the portion where the toner is adhered and the portion where the medium is exposed are often repeated at intervals of a few hundreds of μm. Since the toner and the medium have different reflectances, the amount of received light will not be stable even if feedback control is performed when measuring such a fine patch.

  The present invention makes it possible to more accurately measure the amount of toner on a patch having a fine pattern.

In order to achieve the object of the present invention, for example, the measuring apparatus of the present invention comprises the following arrangement. That is,
Used in a printing apparatus comprising a printing unit that prints a toner patch having a second reflectance larger than the first reflectance on a surface of a carrier or a transfer unit having a first reflectance according to print data, A measuring device for measuring the toner amount of a toner patch on a carrier or a transfer unit,
A light projecting means for projecting light onto the surface of the carrier or the transfer unit, and a toner patch surface on the carrier or the transfer unit;
A light receiving means for receiving the light reflected on the surface of the carrier or the transfer portion and the toner patch surface on the carrier or the transfer portion, and measuring an intensity distribution with respect to a light receiving position of the received light;
From the difference between the measured feature value of the waveform of the intensity distribution from the surface of the carrier or the transfer portion and the measured feature value of the waveform of the intensity distribution from the surface of the toner patch on the support or transfer portion. Calculating means for calculating the toner amount of the toner patch;
With
The light projecting unit projects light of a first intensity onto the surface of the carrier or transfer unit based on a timing signal corresponding to positional information of the toner patch on the carrier or transfer unit from the control unit. And a light having a second intensity that is weaker than the first intensity is projected onto the surface of the toner patch on the carrier or the transfer unit.

  According to the present invention, the amount of toner on a patch having a fine pattern can be measured more accurately.

The figure which shows an example of a structure of the printing apparatus which concerns on a 1st Example. Control block diagram of printing apparatus according to first embodiment The figure which shows an example of a structure of the measuring apparatus which concerns on a 1st Example. The figure which shows the measuring method of the toner amount which concerns on 1st Example. Detailed block diagram of the arithmetic unit 306 according to the first embodiment The figure which shows the detection method of the peak position which concerns on 1st Example. The figure which shows the light quantity control method of the laser light source 301 which concerns on a 1st Example. Control block diagram of the measuring apparatus according to the first embodiment The figure which shows the light quantity setting method of the laser light source 301 which concerns on a 2nd Example. The figure which shows the light quantity setting method of the laser light source 301 which concerns on a 2nd Example. The figure which shows the correction method of the measurement signal which concerns on 3rd Example The flowchart of the process which concerns on a 1st Example.

  Embodiments of the present invention will be described below with reference to the drawings. However, the scope of the present invention is not limited to the following examples.

[Example 1]
In this embodiment, a toner amount measuring method in an electrophotographic image forming apparatus will be described. FIG. 1A illustrates an example of an image forming apparatus according to the present exemplary embodiment. The charging roller 104 charges the surface of the photosensitive drum 101. Next, the exposure laser 102 and the polygon mirror 103 create an electrostatic latent image on the photosensitive drum 101 according to the patch data (printing unit). The developing unit 105 forms a toner patch 108 on the photosensitive drum 101. The photosensitive drum 101 is driven by a driving unit (not shown), and the toner patch 108 on the photosensitive drum 101 is transferred to the transfer belt 106. The transfer belt 106 is also driven by a drive unit (not shown), and the toner patch 108 on the transfer belt 106 is transferred onto a recording medium. Thus, an image is formed on the recording medium (print medium).

  The toner amount of the toner patch 108 (toner patch on the transfer portion) formed by the developing device 105 is measured by the measuring device 107. In this embodiment, the measuring device 107 measures the toner patch 108 on the photosensitive drum 101. However, the measuring device 107 can measure a toner patch on an arbitrary medium. For example, as shown in FIG. 1B, the measuring device 107 can measure the toner patch 108 on the transfer belt 106. In this specification, the photosensitive drum 101 may be referred to as a carrier. Further, the transfer belt 106 may be referred to as a transfer portion. In this embodiment, the measuring device 107 measures the toner amount of the toner patch 108 carried on the medium. The measurement object by the measuring device 107 is not limited to the photosensitive drum 101 and the transfer belt 106, and may be any medium carrying toner. In this specification, the term “supporting member or transfer unit” means any medium that supports toner. For example, the “carrier or transfer unit” can be configured to temporarily carry a toner image to be transferred onto a print medium such as paper.

  An example of the measuring apparatus 107 according to the present embodiment is shown in FIG. The laser light source 301 projects light onto the carrier (and the toner patch 108 on the carrier) (light projection means). The condensing lens 302 condenses the laser light from the laser light source 301 at a light irradiation point on the surface of the carrier (on the surface of the transfer unit). The light receiving lens 303 forms an image of reflected light from the carrier on the image sensor of the line sensor 304 (light receiving means). The light receiving lens 303 is configured to form an image of the reflected light on the corresponding image sensor in accordance with the distance from the surface of the carrier at the position where the light is reflected. As described above, the thickness of the toner layer can be determined based on the intensity of the light incident on each image sensor of the line sensor 304.

  The calculation unit 306 can calculate the toner layer thickness and the toner amount by analyzing the signal generated by the line sensor 304. In the present embodiment, the line sensor 304 is used to simultaneously detect the reflection position and the amount of light of the irregularly reflected light. The photodiode 305 may be installed at a position where the light regularly reflected on the carrier can be measured.

  A method in which the measuring device 107 measures the toner amount will be described in detail with reference to FIG. As shown in FIG. 4A, first, the carrier is driven so that the laser from the laser light source 301 irradiates the surface of the carrier on which the toner patch is not formed. Then, the light irregularly reflected on the surface of the carrier enters the line sensor 304. In this way, the line sensor 304 obtains the irregular reflection waveform 401 shown in FIG. The irregular reflection waveform 401 indicates the intensity distribution of the light incident on the line sensor 304 with respect to the light receiving position.

  Next, as shown in FIG. 4B, the carrier is driven so that the laser from the laser light source 301 irradiates the toner patch 108. Then, the light irregularly reflected by the toner patch 108 enters the line sensor 304. In this way, the line sensor 304 obtains the irregular reflection waveform 403 shown in FIG.

  In practice, the carrier is driven at a certain speed (process speed). Therefore, the toner patch 108 automatically passes under the measuring device 107. By continuously operating the line sensor at a sufficiently short period, the line sensor 304 can acquire a plurality of waveform data corresponding to the positions of the plurality of toner patches 108.

  FIG. 5 shows an example of the configuration of the calculation unit 306. The toner amount calculation process will be described with reference to FIG. The waveform data detected by the line sensor 304 is stored in the storage unit 501. The position detection unit 502 detects the peak position of the waveform indicated by the waveform data stored in the storage unit 501. Here, the peak position indicates a pixel position showing the highest intensity. The position detection unit 502 compares the waveform 401 of light reflected on the surface of the carrier with the waveform 403 of light reflected on the toner patch. The position detection unit 502 detects the amount of movement of the peak position between the waveform 401 and the waveform 403. The amount of movement of the peak position corresponds to the height of the toner from the surface of the carrier.

  The light amount calculation unit 503 calculates the area of the peak portion of the waveform indicated by the waveform data stored in the storage unit 501. Specifically, the light quantity calculation unit 503 calculates the area of the peak portion of the light waveform 401 reflected on the surface of the carrier and the light waveform 403 reflected on the toner patch. The light quantity calculation unit 503 detects the amount of change in the area of the peak portion between the waveform 401 and the waveform 403. The amount of change in the area of the peak portion corresponds to the amount of change in the amount of irregularly reflected light.

  The toner amount calculation unit 505 calculates the toner amount on the carrier based on the movement amount of the peak position detected by the position detection unit 502 and the change amount of the area of the peak portion detected by the light amount calculation unit 503. The toner amount can be calculated based on, for example, a look-up table held by the toner amount calculation unit 505. The toner amount can also be calculated by the toner amount calculation unit 505 performing calculation according to an appropriate calculation formula.

  As described above, the line sensor 304 can acquire waveform data corresponding to the positions of the plurality of toner patches 108. The toner amount calculation unit 505 can calculate the toner amount (toner thickness) for each waveform. The toner amount calculation unit 505 can also calculate the toner amount for the entire toner patch 108 from the toner amount corresponding to each position of the toner patch 108.

  As described above, the position detection unit 502 (and the light amount calculation unit 503) detects peaks in the waveforms 401 and 403. In this embodiment, the position detection unit 502 performs fitting with a Gaussian function in order to detect a peak. The position detection unit 502 performs fitting using the least square method. Then, the peak position is detected using the parameters of the Gaussian function after the fitting.

この式を波形データにフィッティングすることにより得られるμ及びＡを、波形の特徴量とすることができる。位置検出部５０２はこうして得られたパラメータμからピーク位置を求めることができる。 The Gaussian function is a function represented by formula (1) having a bell-shaped peak. In the formula (1), μ is a parameter indicating the X coordinate of the peak position. A is a parameter indicating the height and width of the peak.

Μ and A obtained by fitting this expression to waveform data can be used as waveform feature quantities. The position detection unit 502 can obtain the peak position from the parameter μ thus obtained.

In this embodiment, fitting with a Gaussian function was performed. However, fitting with an expression other than a Gaussian function may be performed. For example, for example, a Lorentz function (formula (2)) or a quadratic function (formula (3)) can be used. Further, the peak position may be obtained by detecting the maximum value.

  FIG. 2 is a block diagram illustrating a printing process performed by the image forming apparatus according to the present embodiment. In the image forming process 201, a charging process 202, an exposure process 203, a developing process 204, a transfer process 205, and a fixing process 206 are sequentially performed. In this embodiment, a measurement process 207 is performed after the development process 204 or the transfer process 205. In the measuring step 207, the measuring device 107 measures the toner amount of the toner patch. According to the measurement result in the measurement step 207, a transfer control step 208, a development control step 209, and an exposure control step 210 are performed.

  Based on the comparison result between the patch data used to form the toner patch 108 and the measurement result in the measurement step 207, the print control steps 208 to 210 are performed so that the formed image has an ideal color. Done. For example, in the transfer control step 208, the transfer current in the transfer step 205 is controlled. In the development control step 209, the development bias voltage or toner replenishment amount in the development step 204 is controlled. In the exposure control step 210, for example, the gradation γ characteristic is controlled.

  In the exposure control step 210, the output of the exposure laser 102 may be directly controlled. On the other hand, in the exposure control step 210, generation of print data used for driving the image forming apparatus may be controlled. For example, the process of converting input image data into print data by the image forming apparatus according to the present embodiment may be controlled in the exposure control step 210. Further, the exposure control process 210 may control a process in which an information processing apparatus such as a computer generates print data input to the image forming apparatus according to the present embodiment from the image data. Each of the print control steps 208 to 210 can be performed by, for example, the controller 506 shown in FIG.

  As described above, the position detection unit 502 (and the light amount calculation unit 503) detects peaks in the waveforms 401 and 403. However, the accuracy of peak detection depends on the intensity of light incident on the line sensor 304. Hereinafter, the relationship between the light amount and the peak detection accuracy will be described with reference to FIG. In FIG. 6A, the waveform 602 is fitted to the imaging waveform 601. As shown in FIG. 6A, there is a difference between the peak position of the imaging waveform 601 and the peak position of the waveform 602.

  The graph in FIG. 6B shows the relationship between the output laser power of the laser light source 301 and the above-described deviation. As shown in FIG. 6B, the deviation increases as the laser power decreases. That is, more accurate fitting can be performed by increasing the laser power. As a result, the peak position can be detected more accurately.

  However, generally, the reflection characteristic of the carrier does not match the reflection characteristic of the toner surface. In the example of FIG. 4, the reflectance of the carrier is lower than the reflectance of the toner surface. Therefore, the amount of light reflected by the carrier and entering the line sensor 304 is smaller. On the other hand, the amount of light reflected by the toner surface and incident on the line sensor 304 is larger. If the incident light amount is too large, the light amount value measured by the line sensor 304 is saturated, and an accurate waveform cannot be obtained.

  As described above, the appropriate output of the laser light source 301 varies depending on whether light is incident on the carrier surface or the toner surface. In this embodiment, the output of the laser light source 301 is controlled so that the measurement value by the line sensor 304 is not saturated and the amount of light incident on the line sensor 304 is sufficiently large. In this embodiment, the output of the laser light source is controlled according to the reflectance at the point where the light from the laser light source 301 is incident. For example, it is determined whether the light from the laser light source 301 is incident on the carrier surface or the toner surface (determination means). The output of the laser light source 301 is controlled according to this determination result.

  In general, the carrier has a low reflectance and the toner has a high reflectance. In this case, the laser light source 301 may project stronger light on the carrier surface and project weaker light on the toner surface. Since the peak position of the waveform can be detected more accurately in this way, the toner amount can be measured more accurately.

The light quantity control method will be described in more detail with reference to FIG. In FIG. 7, the carrier 701 to which the toners 702 and 703 are attached passes through the measuring device 107. The time when the position P ₀ on the carrier 701 passes through the measuring device 107 is assumed to be t ₀ . Similarly, the times at which the positions P _{1 to} P ₅ on the carrier 701 pass through the measuring device 107 are t ₁ to t ₅ .

In FIG. 7, toner adheres between P ₀ and P ₁ , between P ₂ and P _3, and between P ₄ and P ₅ . The position where the toner adheres is controlled by a control signal input to the exposure laser 102. The time required from when the control signal is input to the exposure laser 102 until the toner image formed according to the control signal passes through the measuring device 107 is usually constant. Therefore, when the control unit 801 of the measuring apparatus 107 acquires this control signal, the measuring apparatus 107 can know the times t _{0 to} t ₅ . For example, the time t ₂ is the time after the above-described required time from the input of the control signal (corresponding to the position P ₂ ) for starting the generation of the toner 703. In this way, the control unit 801 of the measuring apparatus 107 can generate a timing signal for controlling the output of the laser light source 301.

By driving the laser light source 301 according to this timing signal, the output of the laser light source 301 can be lowered at t ₀ to t ₁ , t _{2 to} t ₃ , and t _{4 to} t ₅ . For example, from t _{2 to} t ₃ , the light amount of the laser light source 301 is made lower as 712. In addition, from t _{3 to} t ₄ , the light amount of the laser light source 301 is increased as in 711.

As another method, by using the toner 702 (first toner patch) as a trigger, the measuring device can know that the times t ₀ and t ₁ have come. That is, a predetermined pattern such as the toner 702 is formed on the carrier 701 by driving the exposure laser 102 in accordance with the first control signal (first print data). When the measuring device 107 confirms that this predetermined pattern has arrived, the measuring device 107 can know that the times t ₀ and t ₁ have arrived. Further, a second control signal (second printing) indicating the toner 703 (second toner patch) after a predetermined time (t ₂ −t ₀ ) after the first control signal is input to the exposure laser 102. Data) is input to the exposure laser 102. That measuring device 107 from the time t ₀ when a predetermined time has elapsed, the toner 703 can be determined that reached.

By acquiring the control signal inputted to the exposure laser 102, measuring device 107 can know the time between time t ₁ and time t _2. Similarly, the measuring device 107 can also know the times t _{2 to} t ₃ , the times t _{3 to} t ₄ , and the times t _{4 to} t ₅ . In this way, the measuring device 107 can know the times t2 to t5.

  The process according to the present embodiment will be described with reference to FIG. 8 showing an example of the measurement apparatus 107 and FIG. 12 showing an example of the process performed by the measurement apparatus 107. In step S <b> 1301, the timing generation unit 805 included in the control unit 801 acquires the toner position information 706 from the print data generation unit 507. When printing an image based on the input image data, the print data generation unit 507 generates print data for controlling the exposure laser 102 based on the image data. In the flowchart of FIG. 12, since the toner amount is measured, the print data generation unit 507 generates print data for printing a predetermined measurement patch.

  The exposure laser 102, the polygon mirror 103, the charging roller 104, and the developing device 105 adhere toner to the photosensitive drum 101 based on the print data generated by the print data generation unit 507. The timing generation unit 805 acquires this print data, and extracts toner position information 706 indicating where the toner adheres on the carrier. The obtained toner position information 706 is stored in the information holding unit 804 included in the timing generation unit 805. In step S <b> 1301, the timing generation unit 805 further acquires speed information 710 indicating the time from when the print data is input to the laser light source 301 until the formed toner image passes through the measuring device 107.

  In step S1302, the timing generation unit 805 generates a timing signal 807 indicating the timing for switching the output of the laser light source 301. The timing signal 807 can be generated by the timing generation unit 805 as described with reference to FIG. That is, the timing generation unit 805 determines whether toner is present at a position where the laser is irradiated according to the toner position information 706, and generates a timing signal 807.

  In step S1303, the timing generation unit 805 sends the generated timing signal 807 to the light amount switching unit 808. In step S <b> 1304, the light amount switching unit 808 included in the control unit 801 switches the output of the laser light source 301 so as to emit a laser having a prescribed intensity in accordance with the timing signal 807. In step S 1305, the calculation unit 306 calculates the toner amount on the photosensitive drum 101 based on the waveform measured by the line sensor 304. The calculated toner amount is fed back to the controller 506. The controller 506 controls the print data generation unit 507 and the process control unit 508 according to the toner amount.

  In the present embodiment, the method of changing the incident light intensity according to the presence or absence of toner on the carrier has been mainly described. However, the incident light intensity can be changed according to the type of toner on the carrier. For example, the timing generation unit 805 can acquire toner position information 706 indicating which color toner is attached to which position on the carrier. In this way, the timing generation unit 805 can control the light amount switching unit 808 and the laser light source 301 so as to project light having an intensity matching the color of the toner. For example, light of different intensities may be projected on each of the CMYK four color toners.

  Further, the light amount switching unit 808 can control the light intensity projected by the laser light source 301 in consideration of the light reflectance of the carrier. Further, the light amount switching unit 808 can control the light receiving sensitivity of the line sensor 304 according to the presence or absence of toner on the carrier. In this embodiment, the description has been made on the assumption that the toner has lower light reflectance than the carrier. However, the method of this embodiment can also be applied to the case where the toner has a higher light reflectance than the carrier. In this case, the laser beam intensity on the toner surface may be made lower than the laser beam intensity (first intensity) on the carrier.

  In this embodiment, the timing generation unit 805 receives speed information 710 from the process control unit 508 indicating the time from when the print data is input to the laser light source 301 until the formed toner image passes through the measurement device 107. I got it. However, the time from when the predetermined print data generated by the print data generation unit 507 is input to the laser light source 301 until the measurement device 107 observes the toner image according to the print data may be actually measured.

[Example 2]
In this embodiment, before measuring the toner amount according to the first embodiment, a belt having a known size is measured to determine a belt conveyance speed and an appropriate amount of projection light. In the present embodiment, the same reference numerals are given to the same elements as those in the first embodiment, and the description thereof is omitted. FIG. 9 is a diagram for explaining the present embodiment. In this embodiment, toners 702 and 703 having a known length formed on the carrier 701 are measured using a laser light source 301 having a constant output. The length L (905) of the patch can be measured using, for example, an apparatus arranged in the vicinity of the measuring apparatus 107.

The line sensor measures the intensity of light reflected from the toner surface of the carrier 701 or the toners 702 and 703. In this way, the calculation unit 306 can obtain the light amount profile 903. According to the light amount profile 903, the time taken for the toner 703 having a length L to pass is Δt = t ₃ −t ₂ . Thus, the carrying speed of the carrier can be calculated as S = L / Δt. The conveyance speed of the carrier can also be calculated by measuring a plurality of patches and obtaining a statistical value, for example, an average value.

  From the light quantity profile 903, it is possible to know the light quantity 901 of light reflected by the toner surface and the light quantity 902 of light reflected by the carrier surface. Using these, the light amounts 711 and 712 in FIG. 7 can be determined. When the light amounts 711 and 712 are determined, the measurement value of the line sensor 304 is set within a predetermined range. For example, it is necessary to prevent the measurement value of the line sensor 304 from being saturated. For example, as shown in FIG. 10, it is necessary to prevent the output voltage from exceeding the saturation voltage level 1002 in the waveform 1001 output by the line sensor 304.

  In order to prevent this, the laser output or the sensor sensitivity may be set so that the peak voltage 1004 falls within the allowable range 1003 lower than the saturation voltage level. For example, appropriate light amounts 711 and 712 can be determined by repeating the measurement while changing the output of the laser light source 301.

  The measured conveyance speed or the determined light amount may be stored in the light amount switching unit 808, for example. In this case, it is not necessary to perform these measurements every time the measurement of the toner amount is started. The measurement may be performed again when a predetermined number of sheets are printed or when the peak voltage output from the line sensor 304 fluctuates. Further, different light amounts 711 and 712 may be determined according to the color of the toner.

[Example 3]
In Example 1, the incident light intensity varied depending on the presence or absence of toner on the carrier. Therefore, in order to obtain the amount of light reflected by the carrier or the toner surface, it is necessary to correct the measurement value by the line sensor 304 according to the incident light intensity. Hereinafter, a method for correcting the measurement value by the line sensor 304 will be described. In the present embodiment, the same elements as those in Embodiments 1 and 2 are denoted by the same reference numerals, and description thereof is omitted.

  FIG. 11 shows the time change of the signal when the toner adhesion amount is measured while switching the light amount to 711 or 712. Reference numeral 1101 in FIG. 11 is a light quantity timing chart. When measuring the carrier 701 having a low reflectance, a laser beam with a large light amount 711 is irradiated. Further, when measuring the highly reflective toner 703, a laser with a small light quantity 712 is emitted. Therefore, the line sensor 304 outputs a signal such as a waveform 1102 with little fluctuation.

  By multiplying the waveform 1102 by the ratio of the light quantity 711 and the light quantity 712, a waveform 1103 that correctly reflects the intensity of the reflected light can be obtained. Specifically, the calculation unit 306 acquires the timing signal 807 from the timing generation unit 805. The calculation unit 306 acquires values indicating the light amounts 711 and 712 included in the light amount switching unit 808. In this way, the calculation unit 306 corrects the waveform 1102 acquired from the line sensor 304.

Claims (10)

Used in a printing apparatus comprising a printing unit that prints a toner patch having a second reflectance larger than the first reflectance on a surface of a carrier or a transfer unit having a first reflectance according to print data, A measuring device for measuring the toner amount of a toner patch on a carrier or a transfer unit,
A light projecting means for projecting light onto the surface of the carrier or the transfer unit, and a toner patch surface on the carrier or the transfer unit;
A light receiving means for receiving the light reflected on the surface of the carrier or the transfer portion and the toner patch surface on the carrier or the transfer portion, and measuring an intensity distribution with respect to a light receiving position of the received light;
From the difference between the measured feature value of the waveform of the intensity distribution from the surface of the carrier or the transfer portion and the measured feature value of the waveform of the intensity distribution from the surface of the toner patch on the support or transfer portion. Calculating means for calculating the toner amount of the toner patch;
With
The light projecting unit projects light of a first intensity onto the surface of the carrier or transfer unit based on a timing signal corresponding to positional information of the toner patch on the carrier or transfer unit from the control unit. And a second intensity light that is weaker than the first intensity is projected onto the surface of the toner patch on the carrier or transfer portion. Used in a printing apparatus comprising a printing unit that prints a toner patch having a second reflectance smaller than the first reflectance on a surface of a carrier or a transfer unit having a first reflectance according to print data, A measuring device for measuring the toner amount of a toner patch on a carrier or a transfer unit,
A light projecting means for projecting light onto the surface of the carrier or the transfer unit, and a toner patch surface on the carrier or the transfer unit;
A light receiving means for receiving the light reflected on the surface of the carrier or the transfer portion and the toner patch surface on the carrier or the transfer portion, and measuring an intensity distribution with respect to a light receiving position of the received light;
From the difference between the measured feature value of the waveform of the intensity distribution from the surface of the carrier or the transfer portion and the measured feature value of the waveform of the intensity distribution from the surface of the toner patch on the support or transfer portion. Calculating means for calculating the toner amount of the toner patch;
With
The light projecting unit projects light of a first intensity onto the surface of the carrier or transfer unit based on a timing signal corresponding to positional information of the toner patch on the carrier or transfer unit from the control unit. And a light having a second intensity stronger than the first intensity is projected onto the surface of the toner patch on the carrier or the transfer unit. The print data includes first print data representing a first toner patch and second print data representing a second toner patch,
A second time after the first print data is input to the printing unit, the second print data is input to the printing unit;
The light receiving means detects that the first toner patch has reached a position where the light is projected from the amount of light received;
The controller switches the light of the first intensity and the light of the second intensity to the light projecting means according to the second print data after the predetermined time from the detection of the first toner patch. The measuring apparatus according to claim 1, wherein:   The control unit holds a time required for the toner patch according to the print data to reach a position where the light is projected after the print data is input to the printing unit. The measuring device according to claim 1 or 2.   5. The apparatus according to claim 1, further comprising a setting unit configured to set an intensity of light projected by the light projecting unit so that a light amount measured by the light receiving unit is within a predetermined range. The measuring device according to claim 1.   6. The printing apparatus according to claim 1, wherein the printing apparatus controls printing so that the amount of toner adhering to the print medium is constant with reference to the amount of toner measured by the measuring apparatus. The measuring device according to item. Used in a printing apparatus comprising a printing unit that prints a toner patch having a second reflectance larger than the first reflectance on a surface of a carrier or a transfer unit having a first reflectance according to print data, A measurement method performed by a measurement device that measures the toner amount of a toner patch on a carrier or a transfer unit,
A light projecting step in which the light projecting means of the measuring device projects light onto the surface of the carrier or transfer unit and the surface of the toner patch on the support or transfer unit;
The light receiving means of the measuring device receives the light reflected on the surface of the carrier or transfer portion and the toner patch surface on the carrier or transfer portion, and measures the intensity distribution of the received light with respect to the light receiving position. A light receiving process;
The calculation means of the measurement device includes the measured feature amount of the waveform of the intensity distribution from the surface of the carrier or transfer unit and the waveform of the intensity distribution from the surface of the toner patch on the carrier or transfer unit. A calculation step of calculating a toner amount of the toner patch from a difference from the feature amount of
With
In the light projecting step, light of a first intensity is projected onto the surface of the carrier or transfer unit based on a timing signal corresponding to position information of the toner patch on the carrier or transfer unit from the control unit. And a light having a second intensity that is weaker than the first intensity is projected onto the surface of the toner patch on the carrier or the transfer unit. Used in a printing apparatus comprising a printing unit that prints a toner patch having a second reflectance smaller than the first reflectance on a surface of a carrier or a transfer unit having a first reflectance according to print data, A measurement method performed by a measurement device that measures the toner amount of a toner patch on a carrier or a transfer unit,
A light projecting step in which the light projecting means of the measuring device projects light onto the surface of the carrier or transfer unit and the surface of the toner patch on the support or transfer unit;
The light receiving means of the measuring device receives the light reflected on the surface of the carrier or transfer portion and the toner patch surface on the carrier or transfer portion, and measures the intensity distribution of the received light with respect to the light receiving position. A light receiving process;
The calculation means of the measurement device includes the measured feature amount of the waveform of the intensity distribution from the surface of the carrier or transfer unit and the waveform of the intensity distribution from the surface of the toner patch on the carrier or transfer unit. A calculation step of calculating a toner amount of the toner patch from a difference from the feature amount of
With
In the light projecting step, light of a first intensity is projected onto the surface of the carrier or transfer unit based on a timing signal corresponding to position information of the toner patch on the carrier or transfer unit from the control unit. And a light having a second intensity higher than the first intensity is projected onto the surface of the toner patch on the carrier or the transfer unit. Used in a printing apparatus comprising a printing unit that prints a toner patch having a second reflectance larger than the first reflectance on a surface of a carrier or a transfer unit having a first reflectance according to print data, A measuring device for measuring the toner amount of a toner patch on a carrier or a transfer unit,
Control means for controlling the light projecting unit that projects light onto the surface of the carrier or transfer unit and the toner patch surface on the carrier or transfer unit;
Receives the light reflected from the surface of the toner patch on the carrier or transfer portion and the feature quantity of the intensity distribution of the reflected light obtained by receiving the light reflected from the surface of the carrier or the transfer portion. Calculating means for calculating the toner amount of the toner patch from the difference from the characteristic amount of the waveform of the intensity distribution of the reflected light obtained by
With
The control means includes
Based on a timing signal corresponding to the position information of the toner patch on the carrier or the transfer unit, control is performed so as to project light having a first intensity onto the surface of the carrier or the transfer unit, and the carrier or Control is performed so that light having a second intensity lower than the first intensity is projected onto the surface of the toner patch on the transfer unit. Used in a printing apparatus comprising a printing unit that prints a toner patch having a second reflectance larger than the first reflectance on a surface of a carrier or a transfer unit having a first reflectance according to print data, A measurement method performed by a measurement device that measures the toner amount of a toner patch on a carrier or a transfer unit,
A control step in which the control means of the measuring device controls the surface of the carrier or the transfer unit and the light projecting unit that projects light to the surface of the toner patch on the carrier or the transfer unit;
The characteristic amount of the waveform of the intensity distribution of the reflected light obtained by the calculation means of the measuring device receiving the light reflected from the surface of the carrier or transfer unit, and the surface of the toner patch on the carrier or transfer unit A calculation step of calculating a toner amount of the toner patch from a difference from a characteristic amount of a waveform of the intensity distribution of reflected light obtained by receiving the light reflected from
With
In the control step,
Based on a timing signal corresponding to the position information of the toner patch on the carrier or the transfer unit, control is performed so as to project light having a first intensity onto the surface of the carrier or the transfer unit, and the carrier or Control is performed so that light having a second intensity lower than the first intensity is projected onto the surface of the toner patch on the transfer portion.

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