JP2017173060A - Measurement device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To detect a thickness of a toner image with high accuracy.SOLUTION: A measurement device is configured to emit light toward a carrier conveying a toner image; observe the emitted light to thereby an incident position of the light in a direction vertical to a surface of the carrier is measured; and calculate a thickness of the toner image on the basis of an incident position of first light measured by observing the first light incident upon the surface of the toner image and an incident position of second light measured by simultaneously observing the second light incident upon the surface of the carrier and the first light. The first and second light are emitted to a position apart in a direction vertical to a conveyance direction of the toner image, and an irradiation direction of the first light and second light is a direction at a right angle with respect to the direction vertical to the conveyance direction of the toner image.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a measuring apparatus.

  The color of an image formed by an image forming apparatus employing an electrophotographic method or electrostatic recording method such as a copying machine, a laser printer, or a facsimile varies depending on changes in various physical parameters. For example, since the latent image potential, the toner replenishment amount, the transfer efficiency, or the like changes due to fluctuations in temperature or humidity, the amount of toner attached to the photosensitive drum or transfer belt is not constant.

  Patent Document 1 discloses a method of measuring the thickness (layer thickness) of a toner patch using a laser displacement meter. Specifically, spot light is irradiated onto a carrier that carries a toner patch. Then, the reflected light forms an image at a position corresponding to the thickness of the toner patch on the carrier. The thickness of the toner patch is measured by detecting a change in the light imaging position when the toner patch passes through the spot light irradiation position using PSD (Position Sensing Device) or the like. Based on the thickness of the toner patch, feedback control for the image forming process is performed.

JP-A-8-327331

  However, the method described in Patent Document 1 has a problem that an error occurs in a measurement value due to vibration and waviness of the carrier. That is, in the method described in Patent Document 1, the height of the toner patch surface is detected as the distance from the reference surface of the carrier. Therefore, when the distance between the surface of the carrier and the reference surface, in other words, the distance between the surface of the carrier and the measuring device changes due to mechanical factors such as vibration and waviness, an error occurs in the measured value.

  An object of the present invention is to provide a measuring apparatus capable of detecting the thickness of a toner image with high accuracy.

In order to achieve the above object, a measuring apparatus according to the present invention comprises:
Measuring means for measuring the incident position of the light in a direction perpendicular to the surface of the carrier by irradiating light toward the carrier carrying the toner image and observing the irradiated light;
The first light incident position measured by observing the first light incident on the surface of the toner image and the second light incident on the surface of the carrier are observed simultaneously with the first light. Calculating means for calculating the thickness of the toner image based on the incident position of the second light measured by
A measuring device comprising:
The measuring means includes an irradiating means for irradiating the first light and the second light, and an observing means for observing the first light and the second light,
The irradiating means irradiates the first light and the second light at a position separated in a direction perpendicular to the toner image transport direction, and the direction is perpendicular to the toner image transport direction. The irradiation directions of the first light and the second light are perpendicular directions.

  With the measuring apparatus according to the present invention, the thickness of the toner image can be detected with high accuracy.

1 is a diagram illustrating a configuration of an image forming apparatus according to an embodiment. Diagram showing an example of feedback control The figure which shows an example of a structure of the measuring apparatus which concerns on Embodiment 1. The figure explaining the measuring method of the thickness of a toner patch The figure explaining the method of measuring the thickness of a toner patch by differential calculation 1 is a block diagram illustrating a functional configuration of a signal processing unit according to a first embodiment. The figure which shows the example of the reflected image imaged in Embodiment 1. Processing flowchart performed in the first embodiment The figure which shows an example of a structure of the measuring apparatus which concerns on Embodiment 2. The figure which shows an example of the irradiation optical system used in Embodiment 2. The figure which shows an example of the irradiation optical system used in Embodiment 3 The figure which shows the example of the reflected image imaged in Embodiment 3. Diagram showing how to measure the thickness of a toner patch The figure which shows the imaging range of the area sensor in Embodiment 4. The figure which shows the example of the reflected image imaged in Embodiment 4. The block diagram which shows the function structure of the signal processing part which concerns on Embodiment 5. FIG. FIG. 10 is a diagram illustrating an example of a position detection patch used in the fifth embodiment. FIG. 10 is a diagram illustrating toner patch formation positions according to the fifth exemplary embodiment. Process flowchart performed in embodiment 5 FIG. 10 is a diagram illustrating an example of a position detection patch used in the sixth embodiment. FIG. 10 is a diagram illustrating an example of a position detection patch used in the seventh embodiment. FIG. 10 is a diagram illustrating measurement of a thin film toner image according to an eighth embodiment.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. However, the scope of the present invention is not limited to the following embodiments.

[Embodiment 1]
In the first embodiment, two spot lights are irradiated to the carrier and the toner image, respectively. The obtained image is divided into two, and the toner amount (toner adhesion amount) is calculated using each of the divided images.

(Configuration of image forming apparatus)
FIG. 1 is a diagram illustrating an example of a configuration of an image forming apparatus according to the first embodiment. Image forming apparatuses according to Embodiments 2 to 7 to be described later have the same configuration.

  An image forming apparatus 100 shown in FIG. 1A includes a photosensitive drum 101 as an image carrier, an exposure laser 102, a polygon mirror 103, a charging roller 104, a developing device 105, a transfer belt 106, a measuring device 107, and a fixing device. 110.

  The image forming apparatus 100 is an electrophotographic image forming apparatus. The operation principle of the electrophotographic image forming apparatus is well known, but the operation of the image forming apparatus 100 will be briefly described below.

  First, the surface of the photosensitive drum 101 is charged by the charging roller 104. Next, an electrostatic latent image is created on the surface of the photosensitive drum 101 by the exposure laser 102 via the polygon mirror 103. Next, a toner patch 108 that is a toner image for thickness measurement is formed on the photosensitive drum 101 by the developing unit 105.

  The measuring device 107 measures the toner amount of the toner patch 108 after development. As shown in FIG. 1B, the measuring device 107 may measure the toner amount of the toner patch 108 after being transferred from the photosensitive drum 101 to the transfer belt 106. The procedure for measuring the toner amount for the toner patch 108 on the photosensitive drum 101 and the procedure for measuring the toner amount for the toner patch 108 on the transfer belt 106 are the same.

  Hereinafter, a case where the toner amount of the toner patch 108 on the transfer belt 106 is measured will be described with reference to FIG.

(Feedback control based on toner amount measurement)
FIG. 2 is a control block diagram for feedback control based on toner amount measurement.

  As shown in FIG. 2, the image forming process 201 is controlled according to the result of the toner amount measurement 207. That is, based on the thickness of the toner patch measured by the measuring device 107, the forming means for forming a toner image on the carrier, such as the exposure laser 102 or the developing device 105, is controlled. Specifically, the toner amount measurement 207 is performed as described above after the development step 204 or after the transfer step 205.

  Based on the measured toner amount, transfer control 208, development control 209, and exposure control 210 are performed, and transfer process 205, development process 204, and exposure process 203 are controlled. Specifically, when the toner amount is larger than a specified amount, each process is controlled so as to reduce the toner amount. By such feedback control, color variation in the output image from the image forming apparatus 100 can be suppressed.

  In an electrophotographic image forming apparatus, such a feedback control method is known, and a specific control method is not particularly limited. For example, based on the thickness of the toner patch measured by the measuring device 107, it is possible to control the thickness of the toner when outputting an image having the maximum density. Further, the thickness of the toner patch may be converted into a density, and the density of the output image may be controlled based on the obtained density. Further, the tribo amount (charge amount per unit weight) may be calculated from the thickness of the toner patch in accordance with the toner charge amount measured by another means, and the tribo amount may be controlled. As an example of specific control, the gradation (gamma characteristic) of density output can be adjusted and the image density can be changed by changing the laser output characteristic in exposure control. Further, by adjusting the development bias voltage or the toner supply amount by development control, or by adjusting the transfer current by transfer control, it is possible to change the toner film thickness or tribo amount at the time of maximum density output.

  Such toner amount measurement and feedback control can be performed when the printer environment fluctuates, such as after replacement of the toner cartridge, after printing a predetermined number of sheets, or after turning on the printer main body. When performing feedback control, toner patches of various densities are formed on the photosensitive drum 101 or the transfer belt 106, and the toner amount is measured for each toner patch. Thereafter, the image forming conditions are controlled based on the measurement result. The thickness (or average thickness) of the toner patch 108 is proportional to the toner amount. Therefore, the toner amount can be calculated from the thickness of the toner patch 108 thus calculated, and the thickness of the toner patch 108 thus calculated may be treated as the toner amount. Hereinafter, the calculated thickness of the toner patch 108 is referred to as a toner amount.

(Configuration of measuring device 107)
The measuring apparatus 107 according to the present embodiment includes an irradiation unit that irradiates light toward a carrier that conveys a toner image, and an observation unit that observes the irradiated light, and is in a direction perpendicular to the surface of the carrier. The incident position of light is measured.

  FIG. 3 shows an example of the configuration of the measuring apparatus 107.

  The measuring device 107 includes a laser light source 301, a condensing lens 302, a diffraction grating 303, a light receiving lens 304, an area sensor 305, and a signal processing unit 306.

  The laser light source 301, the condensing lens 302, and the diffraction grating 303 constitute an irradiation unit, and the light receiving lens 304 and the area sensor 305 constitute an observation unit.

  The laser light source 301 is, for example, a laser diode, and irradiates light onto the photosensitive drum 101 or the transfer belt 106 (hereinafter referred to as a carrier). The condensing lens 302 condenses the laser light from the laser light source 301 in a small spot shape.

  In this embodiment, the optical axis of the laser light from the laser light source 301 and the condenser lens 302 is about 90 degrees with respect to the main scanning axis 308, and the elevation angle from the carrier plane is about 45 degrees. Is set. Here, the sub-scanning axis 307 represents an axis parallel to the sub-scanning direction of the carrier (the direction in which the carrier moves, that is, the direction in which the toner image is conveyed).

  The diffraction grating 303 divides the spot light from the laser light source 301 and the condenser lens 302 into two. In the present embodiment, the division is performed so that the two divided spot lights are aligned along the main scanning axis 308. Here, the main scanning axis 308 is the main scanning direction of the carrier (the scanning direction of the laser from the exposure laser 102, and is generally orthogonal to the direction in which the carrier moves and parallel to the surface of the carrier. Direction). It is not necessary to use the diffraction grating 303 to divide the light. For example, a beam splitter or a half mirror can be used.

  The two divided spot lights are incident on the carrier and reflected by the toner patch 108 or the carrier to be measured. The reflected light forms an image on the area sensor 305 through the light receiving lens 304. In the present embodiment, the area sensor 305 is an area-type image sensor, that is, an image sensor in which pixels are two-dimensionally arranged, and captures an image of the irradiated spot light. In this way, different images (reflected images) are obtained according to the difference in the thickness of the toner attached on the carrier.

  In the present embodiment, the area sensor 305 captures two spot light images irradiated on the surface of the toner patch 108 or the surface of the carrier. However, instead of the area sensor 305, another sensor that can simultaneously detect the incident positions of the two spot lights to the sensor in the one-dimensional direction can be used. For example, two line sensors that detect the position of the spot light in the direction parallel to the sub-scanning axis 307 can be used, and the line sensors can be driven in synchronization.

  In the present embodiment, the spot light is incident from a direction inclined with respect to the surface of the carrier, that is, a direction that is not perpendicular to the surface of the carrier. For this reason, the incident position of the spot light on the toner patch 108 changes in a direction parallel to the sub-scanning axis 307 according to the height of the toner patch 108.

  As described above, the position of the irregularly reflected light on the area sensor 305 changes in a direction parallel to the sub-scanning axis 307 according to the change in the height of the measurement target. In the present embodiment, observation of the incident position of the spot light on the surface of the carrier or the toner patch 108 using the area sensor 305 is continuously performed. In this way, a change with time in the incident position of the spot light on the surface of the carrier or the toner patch 108 is detected.

  In the present embodiment, a change in position in the direction along the sub-scanning axis 307 is detected for two spot lights at positions separated in the direction along the main scanning axis 308. For this reason, in this embodiment, an area type image sensor that detects a two-dimensional light distribution is used as the area sensor 305. The reflected image picked up by the area sensor 305 is stored by the signal processing unit 306 and is then used for calculating the toner amount. According to such a measuring apparatus 107, it is possible to simultaneously measure light reflection positions at a plurality of positions separated from each other.

  In this embodiment, as will be described later, the irradiation unit irradiates one surface of the spot light (beam A) onto the surface of the toner patch 108. The irradiation unit irradiates one of the spot lights (beam B) onto the surface of the carrier. More specifically, when the toner patch 108 is conveyed to the irradiation positions of the beams A and B by the carrier, the beam A is irradiated on the surface of the toner patch 108. On the other hand, while the beam A is applied to the surface of the toner patch 108, the beam B is always applied to the surface of the carrier. Then, the observation unit simultaneously observes the beam A and the beam B irradiated to the surface of the toner patch 108 or the surface of the carrier by the irradiation unit. Differential measurement is performed based on the two observation results thus obtained.

  With reference to FIG. 4A, a measuring method of the toner patch shape by the measuring device 107 will be described.

  The area sensor 305 continuously captures a carrier image or toner patch image that reflects light. Specifically, the area sensor 305 performs an operation of accumulating reflected light for a predetermined time based on a set sampling frequency and an operation of outputting a waveform of the reflected light obtained during that time as a reflected image of one frame. repeat. The carrier is driven by the driving roller 401 to move in the direction of the sub-scanning shaft 307 at a constant process speed where the toner patch 108 is placed. That is, the measuring device 107 continuously captures and stores the reflected waveform from the carrier or the toner patch at a certain sampling interval.

  The measuring device 107 starts irradiation of the laser beam and storage of the reflected waveform before the toner patch reaches the irradiation point of the laser beam (beams A and B). The two beams A and B divided by the diffraction grating 303 are reflected by the carrier or the toner patch and simultaneously enter the area sensor 305. The measuring device 107 divides the reflected image captured by the area sensor 305 into a region where the reflected beam A is reflected and a region where the reflected beam B is reflected. Then, the measuring device 107 stores an image in which the beam A is captured and an image in which the beam B is captured as independent image data.

  The measuring device 107 detects the reflection position of the laser beam (or the incident direction of the reflected laser beam on the area sensor 305) by performing signal processing described later on the image data thus obtained. By performing signal processing on each piece of continuously captured image data, the measuring device 107 can generate time-series data indicating changes in the reflected position of laser light over time.

  In the present embodiment, the toner patch 108 is disposed on the carrier so that the toner patch 108 is irradiated with the beam A and the toner patch 108 is not irradiated with the beam B.

(Toner amount calculation method)
A toner amount calculation method using reflection of laser light in this embodiment will be briefly described with reference to FIG.

  As described above, in the present embodiment, spot light is incident from a direction inclined with respect to the surface of the carrier. In FIG. 13A, laser light 1301 is incident on a light irradiation point 1302 on the carrier. In this case, when the area sensor 305 captures an image (reflection image) around the light irradiation point 1302, the laser light reflected on the carrier is observed as a bright spot at the light irradiation point 1302.

  On the other hand, in FIG. 13B, the toner patch 108 on the carrier is moved onto the light irradiation point 1302 by the carrier moving. When the area sensor 305 captures an image (reflection image) around the light irradiation point 1302, the laser light reflected on the carrier is observed as a bright spot at the incident point 1303. Due to the thickness of the toner patch 108, the position of the light irradiation point 1302 in the direction along the surface of the carrier and the position of the incident point 1303 are different.

  More specifically, the position of the incident point 1303 in the direction along the surface of the carrier depends on the position of the incident point 1303 in the direction perpendicular to the surface of the carrier. In other words, the position of the incident point 1303 on the surface in the direction along the surface of the carrier depends on the distance between the reference plane parallel to the surface of the carrier and the position of the incident point 1303. Thus, the position of the incident point 1303 in the direction perpendicular to the surface of the carrier can be determined by measuring the position of the incident point 1303 on the surface in the direction along the surface of the carrier. In other words, the position of the incident point 1303 on the surface in the direction along the surface of the carrier indicates the position of the incident point 1303 in the direction perpendicular to the surface of the carrier.

  Thus, in the image (reflection image) around the light irradiation point 1302 imaged using the area sensor 305, the position of the bright spot when the laser light is incident on the surface of the carrier, and the laser light is the toner patch. A deviation from the position of the bright spot when the light is incident on 108 is detected. For example, assuming that there is no vibration or undulation of the carrier and that the position of the carrier is always constant, the thickness t of the toner patch 108 and the light irradiation point 1302 in the direction along the surface of the carrier. And the distance d between the incident point 1303 and the incident point 1303 are proportional. Based on the detected deviation, the thickness of the toner patch 108 can be calculated. A specific method for calculating the thickness of the toner patch 108 is not particularly limited.

  In this embodiment, the incident position of the beam A on the surface of the toner patch 108 measured when the toner patch 108 passes the incident position of the beam A is measured. Further, the incident position of the beam A on the surface of the carrier measured before or after the toner patch 108 passes the incident position of the beam A is measured. Then, the thickness of the toner patch 108 is calculated based on the difference between these incident positions. Here, the incident position may be an incident position of the beam A in a direction perpendicular to the surface of the carrier, or an incident position of the beam A in a direction along the surface of the carrier.

  However, in another embodiment, the toner is obtained by the difference between the measured value of the incident position of the beam A on the surface of the toner patch 108 and a predetermined value indicating the incident position of the beam A on the surface of the carrier. The thickness of the patch 108 can also be calculated. The predetermined value indicating the incident position of the beam A on the surface of the carrier may be a value predetermined when the image forming apparatus 100 is manufactured, or the beam A on the surface of the carrier periodically. It may be a value measured by measuring the incident position.

  However, it is not essential that the irradiation unit including the laser light source 301 and the observation unit including the area sensor 305 are arranged in the positional relationship illustrated in FIG. If the irradiation direction of the light by the irradiation unit and the observation direction by the observation unit are inclined, that is, if the optical axis of the irradiation unit and the optical axis of the measurement unit are inclined, the light in the direction perpendicular to the surface of the carrier It is possible to measure the incident position.

  On the other hand, as shown in FIG. 3, the angle formed by the irradiation direction of the light from the irradiation unit and the direction of the main scanning axis 308, that is, the direction perpendicular to the toner image conveyance direction is approximately 90 degrees. The following advantages are obtained. That is, an elongated streak-like scratch may occur on the surface of the image forming apparatus using the electrophotographic system in the direction along the sub-scanning axis 307 due to the friction of the cleaning blade.

  If the angle formed by the irradiation direction of the light from the irradiation unit and the sub-scanning axis 307 is about 90 degrees, the light irradiated to such a flaw tends to be regularly reflected. May not be obtained. That is, even if the spot light is irradiated, the shape of the light spot appearing in the captured image obtained by the area sensor 305 may be distorted, and the light spot detection accuracy may be reduced.

  Therefore, since the angle formed by the irradiation direction of the light from the irradiation unit and the main scanning axis 308 is about 90 degrees, such a decrease in detection accuracy can be prevented. Note that the angle formed between the irradiation direction of light from the irradiation unit and the main scanning axis 308 is not strictly limited to 90 degrees, and may be designed to be within a range that is not affected by reflection due to scratches. .

  When the toner patch 108 has irregularities, such as when the toner patch 108 is a halftone image, and the sampling frequency of the area sensor 305 is not sufficiently high, the reflected image has a plurality of positions corresponding to the irregularities. A bright spot appears. Even in such a case, the center position of the bright spot on the image is detected, and the deviation between the detected center position and the bright spot position when the laser light is incident on the surface of the carrier is detected. By detecting, the average thickness of the toner patch 108 can be calculated.

  In an ideal state where the measuring device 107 and the carrier are not vibrating, the thickness (or average thickness) of the toner patch 108 can be obtained as follows. In the following example, the position of the bright spot when the laser beam is incident on the toner patch 108, the position of the bright spot when the laser beam is incident on the surface of the carrier before and after the toner patch, The toner patch thickness is calculated based on

That is, the thickness of the toner patch 108A shown in FIG. 4B can be obtained by multiplying the patch (108A) obtained according to the equation (1) by a predetermined coefficient.
patch (108A) = B- (A + C) / 2 Formula (1)
Further, the thickness of the toner patch 108B shown in FIG. 4B can be obtained by multiplying the patch (108B) obtained according to the equation (1) by a predetermined coefficient.
patch (108B) = D− (C + E) / 2 Formula (2)
In Expressions (1) and (2), A to E respectively indicate bright spots along the sub-scanning axis 307 in the reflected image captured by the area sensor 305 when the laser light is incident on the positions A to E. Indicates the position. The toner patch 108B is a halftone image. D indicates the center of gravity of the position of the bright spot along the sub-scanning axis 307 in a plurality of reflected images captured by the area sensor 305 when the laser light is incident on the position D.

  The method for calculating the toner amount in an ideal state where the measuring device 107 and the carrier are not vibrating has been described above.

  However, the photosensitive drum and the transfer belt vibrate due to rotational unevenness due to the eccentricity of the driving roller 401 that supports them, or fine vibrations transmitted from other motors or the like. As can be understood from FIG. 13B, when the position of the surface of the carrier perpendicular to the surface of the carrier varies, the position of the surface of the toner patch 108 in the direction perpendicular to the surface of the carrier also varies. Then, since the intersection between the laser beam 1301 and the surface of the toner patch 108 also varies, as a result, the position of the incident point 1303 also varies. As described above, because of the vibration of the carrier, the incident position of the irradiated beam on the carrier or the toner patch 108, that is, the incident position of the reflected beam on the area sensor 305 is as shown by a solid line in FIG. Vibrates finely.

  On the other hand, the beam A and the beam B are irradiated to positions close to each other on the surface of the carrier or the surface of the toner patch 108. For this reason, the incident position of the reflected beam A on the area sensor 305 and the incident position of the reflected beam B on the area sensor 305 vibrate similarly. Therefore, the data indicating the incident position of the irradiated beams A and B on the carrier or the toner patch 108 measured by the area sensor 305 includes a similar noise component. The data indicating the incident position of the beam A on the toner patch 108 reflects the shape of the toner patch 108 that is the original measurement target in addition to these noise components. Therefore, by calculating the difference between the incident position of the beam A on the toner patch 108 and the incident position of the beam B on the carrier, undulation and vibration components are removed from the data, and the shape of the toner patch 108 is further improved. It can be determined accurately.

  In this embodiment, the beam A and the beam B are irradiated to positions separated in a direction parallel to the main scanning axis 308. That is, the irradiation positions of the beam A and the beam B in the direction along the sub-scanning axis 307 coincide with each other. In the present embodiment, the axis of the driving roller 401 is parallel to the main scanning axis 308, and the carrier is driven while maintaining the planarity in the main scanning direction. Therefore, even if the carrier vibrates, the same vibration or undulation occurs at the incident positions of the beams A and B on the carrier or the toner patch 108 (common mode noise). According to such an embodiment, by calculating the difference, swell and vibration components can be removed from the measurement data with higher accuracy.

(Configuration and processing of signal processing unit 306)
Next, the configuration of the signal processing unit 306 and the toner amount calculation processing by the signal processing unit 306 will be described with reference to FIG. 6A which is a block diagram showing the functional configuration of the signal processing unit 306.

  The signal processing unit 306 includes a storage unit 601, a division unit 602, and a detection unit configured by an integration unit 603 and a position detection unit 604. The detection unit measures the incident position of light in a direction perpendicular to the surface of the carrier according to the calculation method described above based on the observation result by the observation unit. Specifically, the detection unit observes the incident position of the beam A measured by observing the beam A incident on the surface of the toner patch 108 and the beam B incident on the surface of the carrier simultaneously with the beam A. Thus, the incident position of the beam B measured is detected.

  The signal processing unit includes a calculation unit configured by a difference calculation unit 605, a height calculation unit 606, and a toner amount calculation unit 607. The calculation unit calculates the thickness of the toner patch 108 based on the incident position of the beam A and the incident position of the beam B detected by the detection unit.

  The storage unit 601 stores the reflection image captured by the area sensor 305. The area sensor 305 continuously captures reflected images according to the sampling frequency, and the storage unit 601 stores these images in time order.

  The dividing unit 602 divides each of the reflected images stored in the storage unit 601 into a plurality of image areas according to the position and number of laser beams. In the present embodiment, two laser beams of beam A and beam B are used. Therefore, the dividing unit 602 refers to the positions of the beam A and the beam B and divides the reflected image into a region where the beam A is reflected and a region where the beam B is reflected. In FIG. 6B, the reflected image is divided into a region where the beam A is incident and a region where the beam B is incident, with the dividing line as a boundary.

  The detecting unit configured by the integrating unit 603 and the position detecting unit 604 detects the incident position of the beam A in the direction perpendicular to the surface of the carrier by detecting the position of the beam A in the region where the beam A is reflected. The detection unit detects the incident position of the beam B in the direction perpendicular to the surface of the carrier by detecting the position of the beam B in the region where the beam B is reflected. Specifically, the integration unit 603 integrates the pixel values of the pixel columns in the main scanning direction for each region. In this way, a light amount distribution showing the relationship between the position in the sub-scanning direction and the light amount is obtained for each region. FIG. 6C shows the light amount distribution for each region. In this embodiment, since the beam A and the beam B are spot-like laser beams, the light amount distribution obtained by the integrating unit 603 is a bell-shaped. The accumulating unit 603 performs the process of generating the light amount distribution for each of the reflected images captured continuously.

  FIG. 6B and FIG. 6C show the case where both the beam A and the beam B irradiate the carrier. Therefore, the incident position of the reflected beam A and the incident position of the reflected beam B are substantially the same. On the other hand, FIG. 7A shows a reflection image obtained when the beam A irradiates the toner patch 108 and the beam B irradiates the carrier. The reflected beam A forms an image at a position on the area sensor 305 that is shifted by a distance corresponding to the thickness of the toner patch 108 as compared with the case where the carrier is irradiated. For this reason, the position of the light spot in the reflected image moves in the sub-scanning direction.

  FIG. 7B shows a light amount distribution for each region obtained from the reflection image of FIG. As shown in FIG. 7B, the light amount distribution is also shifted in the sub-scanning direction by a distance corresponding to the thickness of the toner patch 108. Therefore, the thickness of the toner patch 108 can be measured based on the position of the light quantity distribution, for example, the peak position of the light quantity distribution. The method for detecting the peak position from the light amount distribution data is not particularly limited. For example, the peak position can be detected by fitting with a function by the least square method. As an example, there is a method of predicting and calculating a peak position by performing curve fitting using a Gaussian function. The Gaussian function is a function having a bell-shaped peak with x = μ as the center, as shown by the equation (3). The parameter μ obtained by fitting indicates the peak position of the waveform.

  Instead of the Gaussian function, fitting with a function such as a Lorentz function (Expression 4) shown in Expression (4) or a quadratic function (Expression 5) shown in Expression (5) may be performed. In another embodiment, instead of fitting, the position where the light quantity is maximum may be detected as the peak position, or the center of gravity of the light quantity distribution may be calculated as the peak position.

The position detection unit 604 detects the peak position of the light amount distribution for each region generated by the integration unit 603 using the method described above. The position detection unit 604 performs processing for detecting a peak position for each of the reflected images that are continuously captured. In this way, the incident position on the area sensor 305 in the sub-scanning direction of the reflected beam A and the reflected beam B is detected for each of the reflected images. By plotting the time (or the moving distance of the carrier) and the incident position of the reflected beam A or B on the area sensor 305 in the sub-scanning direction, waveforms A and B shown in FIG. 5 are obtained. Hereinafter, the waveform thus obtained is referred to as beam (A or B) profile (cross-sectional shape) data. This profile data indicates the temporal change of the incident position on the surface of the carrier or the toner patch 108 for the beam A or the beam B.

  In another embodiment, the profile data includes time (or travel distance of the carrier) and the incident position of the beam A or B on the surface of the carrier or toner patch 108 in a direction perpendicular to the surface of the carrier. Also good. As described above, from the incident position of the laser light on the area sensor 305, the incident position of the laser light in the direction perpendicular to the surface of the carrier or the surface of the carrier or the toner patch 108 can be calculated.

  The difference calculation unit 605 calculates the difference between the profile data. Specifically, the difference calculation unit 605 calculates a difference (waveform AB) between the profile data of the beam A and the profile data of the beam B. The waveform AB thus obtained reflects the shape of the toner patch 108, but noise due to vibration or undulation is removed.

  The height calculation unit 606 calculates the thickness of the toner patch 108 according to the formula (1) or the formula (2) using the waveform AB calculated by the difference calculation unit 605. By using the waveform AB from which noise has been removed, the shape of the toner patch 108 can be calculated with high accuracy.

  The toner amount calculation unit 607 converts the thickness of the obtained toner patch 108 into a toner concentration or a toner volume as necessary. The toner patch thickness (toner amount), toner concentration or toner volume calculated in this way is used for control of each process.

  However, it is not indispensable to calculate a profile indicating the change in incident position with time. For example, the difference between the measured value indicating the incident position of the beam A on the surface of the toner patch 108 and the measured value indicating the incident position of the beam B on the surface of the carrier can be calculated. Based on the difference between this difference and a predetermined value indicating the difference between the incident positions of the beams A and B on the surface of the carrier, the thickness of the toner patch 108 can be calculated.

  Hereinafter, processing performed by the signal processing unit 306 will be described with reference to the flowchart of FIG.

  In step S801, the area sensor 305 starts imaging. The area sensor continuously captures images according to the designated sampling frequency.

  In step S <b> 802, the storage unit 601 starts storing the reflection image captured by the area sensor 305 before the beam A enters the toner patch 108 after the toner patch 108 is formed on the carrier. Imaging by the area sensor 305 and storage by the storage unit 601 are performed until the toner patch 108 to be measured passes through the incident position of the beam A.

  In step S803 and subsequent steps, processing is performed on the obtained reflection image. The processing after step S803 may be performed after the imaging by the area sensor 305 and the storage by the storage unit 601 are completed. Further, the processing after step S803 may be performed on the reflection image already stored in the storage unit 601 while the imaging by the area sensor 305 and the storage by the storage unit 601 are continued.

  In step S803, the dividing unit 602 divides the reflected image into a plurality of regions as described above.

  In step S804, the integration unit 603 generates a light amount distribution for each region as described above.

  In step S805, the position detection unit 604 detects the peak position for each light amount distribution as described above.

  The processes in steps S803 to S805 are performed for all the reflection images stored in the storage unit 601. That is, after step S805, it is determined whether all the reflected images have been processed. If all the reflected images have not been processed, the process returns to step S803, and the process for the next reflected image is performed. On the other hand, if all the reflected images have been processed, the process proceeds to step S806.

  In step S806, the difference calculation unit 605 removes the vibration component and the swell component from the profile data by calculating the difference of the profile data as described above.

  In step S <b> 807, the height calculation unit 606 calculates the thickness of the toner patch 108 using the difference calculated by the difference calculation unit 605 as described above.

  In step S808, the toner amount calculation unit 607 executes the toner amount calculation by the toner amount calculation unit 607 based on the calculated toner height.

[Embodiment 2]
In the first embodiment, a plurality of laser beams are obtained by dividing the laser beam from the laser light source 301 having one emission point by the diffraction grating 303. In Embodiment 2, a plurality of laser beams are obtained using a laser light source having a plurality of light emitting points.

  Hereinafter, the second embodiment will be described with reference to FIGS. 9 and 10 showing an example of the configuration of the measuring apparatus 107 according to the present embodiment.

  The configuration of the image forming apparatus according to the present embodiment is similar to that of the image forming apparatus according to the first embodiment, and the same reference numerals are given to the same configurations. Hereinafter, the description of the same configuration as that of the first embodiment will be omitted. In the first embodiment, three devices, that is, a laser light source 301, a condenser lens 302, and a diffraction grating 303 are used. On the other hand, as shown in FIG. 9, in the second embodiment, two devices, a laser light source 901 and a condenser lens 902 are used. In this manner, the diffraction grating can be omitted, and it is not necessary to adjust the attachment position of the diffraction grating, so that the manufacturing cost of the image forming apparatus can be reduced. In addition, by reducing the number of components constituting the optical system, it is easy to improve the accuracy of the laser beam irradiation position by adjusting the mounting positions of components such as the laser light source 901 and the condenser lens 902.

  10A and 10B show detailed configurations and arrangements of the laser light source 901 and the condenser lens 902. FIG.

  In the present embodiment, the laser light source 901 is a multiple light emitting point light source, that is, a laser light source having a plurality of light emitting points and capable of emitting a plurality of laser lights. For example, the laser light source 901 can be a multiple emission point laser diode. As shown in FIG. 10A, the laser light source 901 has two light emitting points 1001. Here, a light emission point axis 1002 passing through two light emission points 1001 is defined. As shown in FIG. 10B, the housing of the laser light source 901 is installed so that the light emitting point axis 1002 is parallel to the main scanning axis 308. Then, the irradiated axis 1003 that passes through the two spot lights imaged on the carrier through the condenser lens 902 is also parallel to the main scanning axis 308. With such an arrangement, two laser beams can be irradiated so that the two spot beams are aligned along the main scanning axis 308, as in the first embodiment.

[Embodiment 3]
In the first and second embodiments, one laser beam is irradiated onto the carrier and the toner patch 108. In Embodiment 3, the thickness of the toner patch 108 is detected with higher accuracy by irradiating the carrier and the toner patch 108 with two or more laser beams, respectively.

  The third embodiment will be described below with reference to FIGS. 11 and 12 showing an example of the configuration of the measuring apparatus 107 according to the present embodiment.

  The configuration of the image forming apparatus according to the present embodiment is similar to that of the image forming apparatus according to the first embodiment, and the same reference numerals are given to the same configurations. Hereinafter, the description of the same configuration as that of the first embodiment will be omitted.

  As shown in FIG. 11A, the laser light source 1101 used in this embodiment is a multi-emission point laser diode having four emission points 1102. Here, a light emission point axis 1103 passing through the four light emission points 1102 is defined. As shown in FIG. 11B, the housing of the laser light source 1101 is installed so that the emission point axis 1103 is parallel to the main scanning axis 308 as in the second embodiment. The four laser beams are incident on the carrier through the condenser lens 1104. At this time, the irradiated axis 1105 passing through the four spot lights imaged on the carrier becomes parallel to the main scanning axis 308.

  In the present embodiment, two of the laser beams (beams A and B) can be incident on the toner patch 108 as the positions of the toner patches 108 formed on the carrier, and the remaining two of the laser beams. The (beams C and D) are adjusted so as to be always incident on the carrier. The area sensor 305 measures the reflected light of the four laser beams irradiated in this way. In other words, the area sensor 305 captures a reflected image including a light spot obtained by four laser beams. Thereafter, the signal processing unit 306 performs image processing on the reflected image according to the flowchart shown in FIG.

  Hereinafter, of the processing performed by the signal processing unit 306, portions different from those of the first embodiment will be described with reference to FIGS.

  12A and 12B show a reflected image and a light amount distribution when the beams A and B are irradiated on the toner patch 108. FIG.

  In the present embodiment, the dividing unit 602 divides the reflection image obtained by the area sensor 305 into four along the dividing line 1201. As shown in FIG. 12A, each divided region includes an image of spot light by each of the beams A to D. For each divided region, the integration unit 603 performs the same processing as in the first embodiment, whereby the light amount distribution shown in FIG. 12B is obtained. As shown in FIG. 12B, the peak positions of the beams A and B are shifted with respect to the beams C and D.

  The position detection unit 604 detects the peak position from the respective reflected images taken in time order, whereby profile data for each of the beams A to D is obtained.

  The difference calculation unit 605 averages the profile data (waveforms C and D) for the beams C and D including noise components caused by vibration or undulation of the carrier. The difference calculation unit 605 also averages the profile data (waveforms A and D) for the beams A and D that reflect the shape of the toner patch 108 and include noise components. Then, the difference calculation unit 605 calculates a difference ((A + B) / 2− (C + D) / 2) between two profile data obtained by averaging. Thereafter, the height calculator 606 calculates the thickness of the toner patch using the difference calculated by the difference calculator 605. According to the present embodiment, even if it is assumed that the sampling frequency of the area sensor 305 is the same, the difference data used for calculating the thickness of the toner patch is twice as much as that of the first embodiment. Calculated using data. For this reason, the amount of high frequency noise mixed in the data can be further reduced.

  In this embodiment, the case where four laser beams are irradiated has been described. However, the number of laser beams may be three, or five or more. In the present embodiment, the number of laser beams incident on the toner patch is the same as the number of laser beams not incident on the toner patch. However, the number of laser beams incident on the toner patch and the number of laser beams not incident on the toner patch may be different depending on the surface state of the carrier or the reflection characteristics of the toner patch surface. For example, the number of each laser beam may be a ratio of, for example, 1 to 3 or 3 to 1.

  In a further embodiment, the beams A to F arranged in the direction along the main scanning axis 308 are irradiated. Here, the toner patch 108 is arranged so that the beams A, B, E, and F are irradiated to the carrier while the beams C and D are irradiated to the toner patch 108. In this case, the waveform C obtained for the beam C can be corrected using the waveforms A to B obtained for the beams A to B. Further, the waveform D obtained for the beam D can be corrected using the waveforms E to F obtained for the beams E to F. Specifically, the difference calculation unit 605 calculates the difference between the waveform C and the waveforms A and B (C− (A + B) / 2) and the difference between the waveform D and the waveforms E and F (D− (E + F) / 2. ) And can be calculated. Such an embodiment is effective when the toner patches 108 have portions having different heights. That is, since the measurement result of the toner patch 108 at each light spot can be corrected using the measurement result of the carrier at the adjacent light spot, the measurement accuracy can be improved.

[Embodiment 4]
In the first to third embodiments, the area sensor 305 is arranged so that the pixel arrangement direction of the area sensor 305 coincides with the main scanning axis 308 and the sub-scanning axis 307.

  In the fourth embodiment, the area sensor 305 is arranged so that the pixel arrangement direction of the area sensor 305 is inclined with respect to the main scanning axis 308 and the sub-scanning axis 307. That is, each side of the rectangular imaging range on the carrier by the area sensor 305 is inclined with respect to the main scanning axis 308 and the sub-scanning axis 307.

  In particular, a case will be described below in which the area sensor 305 is installed so that the pixel arrangement direction of the area sensor 305 forms an angle of about 45 degrees with respect to the main scanning axis 308 and the sub-scanning axis 307, respectively. .

  The configuration of the image forming apparatus according to the fourth embodiment is similar to that of the image forming apparatus according to the first to third embodiments, and the same reference numerals are given to the same configurations. Below, description is abbreviate | omitted about the structure similar to Embodiment 1-3. Hereinafter, a case where four laser beams are irradiated as in the third embodiment will be described. However, the number of laser beams may be two or any other number.

  FIG. 14 shows the relationship between the incident position of the laser beam on the carrier and the imaging range by the area sensor 305.

  The irradiated axis 1401 is an axis through which a laser beam passes a light spot formed on the carrier. In the present embodiment, the area sensor 305 is installed so that the diagonal axis 1402 of the imaging range 1403 by the area sensor 305 is parallel to the irradiated axis 1401. That is, the area sensor 305 is installed so that the diagonal direction of the imaging element of the square area sensor 305 is parallel to the irradiated axis 1401. The signal processing unit 306 performs image processing similar to that of the third embodiment on the reflection image captured by the area sensor 305 arranged in this manner.

  Hereinafter, of the processing performed by the signal processing unit 306, portions different from those of the third embodiment will be described with reference to FIGS.

  In the present embodiment, the dividing unit 602 divides the reflection image obtained by the area sensor 305 into four along the dividing line 1501. Then, the integration unit 603 generates a light amount distribution indicating the relationship between the position in the sub-scanning direction and the light amount by integrating the pixel values in a direction parallel to the main scanning axis 308 for each region. Here, since the pixel arrangement direction is inclined by about 45 degrees with respect to the main scanning axis 308, by integrating the pixel values for the pixels on the axis inclined by about 45 degrees with respect to the pixel arrangement direction, Pixel values can be integrated in a direction parallel to the main scanning axis 308. Using the obtained light quantity distribution, the position detection unit 604, the difference calculation unit 605, and the height calculation unit 606 perform the same processing as in the third embodiment, and thereby the thickness of the toner patch 108 is calculated.

  According to this embodiment, even when the range irradiated by each laser beam is larger than the length of one side of the imaging range by the area sensor 305, the reflected light by each laser beam can be observed. As described above, the area sensor 305 having a smaller light receiving surface as compared with the third embodiment can be used, so that the manufacturing cost of the image forming apparatus 100 can be reduced.

[Embodiment 5]
In the first and second embodiments, the toner patch 108 is formed on the carrier so that the beam A is incident on the toner patch 108 and at the same time the beam B is incident on the carrier. However, the incident position (the position of the light spot) of the laser beam irradiated from the laser light source 301 differs depending on the image forming apparatus 100 due to the influence of the mounting error of the measuring apparatus 107 or the like.

  Generally, the closer the incident position of two laser beams is, the more similar the influence of vibration or undulation on the two laser beams is. Therefore, by calculating the difference between the profile data, the vibration component or undulation component can be removed from the profile data more accurately. can do. However, it is difficult to form the toner patch 108 so that the closer the position of the two light spots is, the closer one of the two light spots passes, and the other light spot does not pass due to an error in the incident position of the laser light. become.

  In the fifth embodiment, a specific position detection patch is formed on the carrier, and the size of the position detection patch is measured using the measuring device 107, whereby the irradiation position of the laser beam on the carrier is determined. To detect. By using this result, it becomes easy to form the toner patch 108 so as to pass through one light spot and not through the other light spot. Specifically, it is used as a measurement toner image and a position detection patch having different lengths in the toner image transport direction depending on the position in the direction perpendicular to the toner image transport direction.

  The configuration of the image forming apparatus according to the fifth embodiment is similar to the image forming apparatus according to the first and second embodiments, and the same reference numerals are given to the same configurations. Hereinafter, the description of the same configuration as in the first and second embodiments is omitted.

  FIG. 16 shows the configuration of the signal processing unit 306 according to this embodiment.

  The measurement apparatus 107 includes a storage unit 601, a division unit 602, an integration unit 603, and a position detection unit 604, as in the first embodiment. The measurement apparatus 107 further includes a position determination unit 1601. The difference calculation unit 605, the height calculation unit 606, and the toner amount calculation unit 607 are unnecessary for the detection of the light spot in the present embodiment, and these are omitted from FIG.

  The detection principle of the light spot in this embodiment will be described with reference to FIGS. 17 (A) and 17 (B).

  In the present embodiment, the positions of the two light spots are detected by measuring the position detection patch. The position detection patch includes a first edge 1701 parallel to the main scanning axis 308 (perpendicular to the sub scanning axis 307) and a second edge inclined with respect to the main scanning axis 308 and the sub scanning axis 307. 1702. As shown in FIG. 17A, the length of the figure composed of the first edge 1701 and the second edge 1702 in the toner image conveyance direction depends on the position in the direction perpendicular to the toner image conveyance direction. Different. Accordingly, by measuring the length of the toner image of the figure in the transport direction at the position of the light spot, the position of the light spot in the direction perpendicular to the transport direction of the toner image can be detected.

In the present embodiment, the first edge 1701 and the second edge 1702 are continuous. The size of the position detection patch is such that both the first edge 1701 and the second edge 1702 pass through both of the two light spots even when there is an error in the mounting position of the measuring device 107. Is set sufficiently large. Hereinafter, the point O where the first edge 1701 and second edge 1702 intersect, the position along the main scanning axis 308 and _{Y 0.} The carrying speed V of the carrier is constant.

  The measurement device 107 acquires profile data for two beams when the position detection patch passes through two light spots. Specifically, the area sensor 305 continuously captures images, and the storage unit 601, the division unit 602, the integration unit 603, and the position detection unit 604 process the obtained reflected image, thereby obtaining profile data. It is done. FIG. 17B shows an example of profile data for beams A and B. FIG.

  In the present embodiment, the profile data indicates the relationship between the time (or the moving distance of the carrier) and the incident position on the area sensor 305 in the sub-scanning direction of the reflected beams A and B, as in the first embodiment. Show. However, in another embodiment, the profile data may indicate the relationship between time (or the moving distance of the carrier) and the amount of light of the reflected beams A and B. Calculation of the light amount from the light amount distribution of the reflected beams A and B can be performed by a known method such as fitting using a function such as a Gaussian function. The amount of reflected light differs depending on whether the laser light is incident on the toner patch or the carrier. Therefore, even if such profile data is used, it is possible to determine whether the laser beam is incident on the toner patch or the carrier at a predetermined time. That is, it is possible to calculate the time from when the first edge 1701 passes the light spot until the second edge 1702 reaches the light spot.

  The position determination unit 1601 refers to the profile data for each of the two laser beams, and for each light spot, after the first edge 1701 passes the light spot, until the second edge 1702 reaches the light spot. The time is calculated. Specifically, the position determination unit 1601 calculates a time t1 from when the first edge 1701 passes through the light spot A generated by the beam A until the second edge 1702 reaches the light spot A. This time t1 is shown in FIG. For example, the position determination unit 1601 can calculate the time from the time when the incident position of the reflected beam A to the area sensor 305 returns to the predetermined range to the time when the incident position deviates from the predetermined range as the time t1. This predetermined range is set in advance as a range on the area sensor 305 where the reflected laser light is incident when the laser light is incident on the carrier. The position determination unit 1601 similarly calculates a time t2 from when the first edge 1701 passes through the light spot B generated by the beam B until the second edge 1702 reaches the light spot B.

  In the present embodiment, the reflected laser light is observed by one area sensor 305. That is, since changes in the incident positions of the light spots A and B on the area sensor 305 are observed by the same area sensor 305, the times t1 and t2 can be measured with high accuracy. The obtained t1 and t2 represent the positions of the light spots A and B in the direction perpendicular to the toner image transport direction.

  Hereinafter, a specific method for calculating the position of the intermediate point between the light spots A and B in the direction perpendicular to the toner image conveyance direction will be described.

The position determination unit 1601 further calculates the movement distance L1 of the position detection patch from the passage of the first edge 1701 through the light spot A to the arrival of the second edge 1702 by the expression L1 = v -Calculate according to t1. Similarly, the position determination unit 1601 calculates the movement distance L2 of the position detection patch from the passage of the first edge 1701 through the light spot B until the second edge 1702 reaches the light spot B, using the equation L2 = Calculate according to v · t2. Then, the movement distance Lc of the position detection patch from when the first edge 1701 passes through the intermediate point between the light spot A and the light spot B until the second edge 1702 reaches this intermediate point is expressed by the equation Lc = (L1 + L2) / 2. Since the second edge 1702 is inclined by about 45 degrees with respect to the main scanning axis 308 and the sub-scanning axis 307, the point O where the first edge 1701 and the second edge 1702 intersect, the light spot A, and the light spot B The distance in the direction along the main scanning axis 308 from the intermediate point is represented by Lc. Therefore, the position Yc along the main scanning axis 308 at the intermediate point between the light spot A and the light spot B can be calculated according to the equation Yc = Y ₀ + Lc.

  When the light spots A and B are shifted by Δp along the sub-scanning axis 307 due to the mounting position of the measuring device 107 being shifted, the timing at which the first edge 1701 passes the light spots A and B is Δt = Δp / Deviation by v. However, since the times t1 and t2 do not change according to Δt and Δp, the calculated position Yc does not include errors due to Δp and Δt. Therefore, according to this embodiment, even if the positions of the light spots A and B in the direction along the sub-scanning axis 307 are shifted, the position Yc can be calculated with high accuracy. Further, according to the present embodiment, even when the distance Δw between the light spots A and B is different from the design value because the positions of the light spots A and B in the direction along the main scanning axis 308 are shifted, The position Yc can be calculated with high accuracy.

  The exposure laser 102 is controlled to form the toner patch 108 such that the edge of the toner patch 108 is positioned at the position Yc of the intermediate point between the light spots A and B detected by the above method. In this way, as shown in FIG. 18, the toner patch 108 can be formed so that the toner patch 108 passes through the light spot A but does not pass through the light spot B. However, the method of calculating the midpoint position of the light spots A and B is not limited to the above method. For example, the average value may be calculated after calculating the positions of the light spots A and B in the direction perpendicular to the toner image conveyance direction based on t1 and t2. Further, the method for controlling the formation position of the toner patch 108 is not limited to the method described above. The shape of the toner patch 108 is not limited to the above. That is, the toner patch 108 can be formed at any position determined based on the values t1 and t2 indicating the positions of the light spots A and B in the direction perpendicular to the toner image conveyance direction. For example, the toner patch 108 can be formed so that the edge of the toner patch 108 is located at an arbitrary internal dividing point between the light spots A and B.

  A toner amount measuring method according to this embodiment will be described with reference to a flowchart of FIG.

  In step S1901, the above-described position detection patch is formed on the carrier by the image forming process 201 using the exposure laser 102, the developing device 105, and the like.

  In step S1902, the measuring apparatus 107 measures the formed position detection patch. This measurement can be performed according to steps S801 to S805 in FIG.

  In step S1903, as described above, the position determination unit 1601 performs the time t1, t2 from when the first edge 1701 passes the light spots A and B until the second edge 1702 reaches the light spots A and B. Is calculated.

  In step S1904, the position determination unit 1601 calculates the coordinate value Yc in the direction along the sub-scanning axis 307 at the intermediate point between the two light spots A and B using the times t1 and t2, as described above. .

  In step S1905, the toner patch 108 is formed by the image forming process 201 using the exposure laser 102, the developing device 105, and the like so that the edge of the toner patch 108 is positioned at the middle position Yc of the light spots A and B. Is done.

  Finally, in step S1906, the measuring device 107 measures the formed toner patch 108. This measurement can be performed according to steps S801 to S808 of FIG.

[Embodiment 6]
In the fifth embodiment, the position of the light spot is measured when the measuring device 107 irradiates the carrier with two laser beams. In the sixth embodiment, as in the third embodiment, the position of the light spot is measured when the measuring device 107 irradiates the support with three or more laser beams. Hereinafter, a case where N laser beams are irradiated will be described.

  In the sixth embodiment, the same position detection patch as that in the fifth embodiment is used. However, the position detection patch is configured such that the first edge 1702 and the second edge 1702 of the position detection patch pass through the N light spots 1 to N by the beams 1 to N. In other words, the position detection patch is configured to be larger than the laser light irradiation area.

  Specifically, the lengths of the first edge 1702 and the second edge 1702 in the direction along the main scanning axis 308 are larger than the spread of the light spots 1 to N in the direction along the main scanning axis 308. FIG. 20A shows the positions of the light spots 1 to N and the position detection patch. Also in the present embodiment, as in the fifth embodiment, the measurement apparatus 107 measures profile data for the beams 1 to N. FIG. 20B shows an example of profile data obtained by the measuring apparatus 107.

Thereafter, in the same manner as in the fifth embodiment, the position determination unit 1601 takes the time from when the first edge 1701 passes through the light spot to the second edge 1702 reaching the light spot for each of the light spots 1 to N. to calculate the t ₁ ~t _N. Further, as in the fifth embodiment, the position determination unit 1601 detects the position from when the first edge 1701 passes through the light spots 1 to N until the second edge 1702 reaches the light spots 1 to N. The movement distances L _{1 to} L _N of the patch are calculated.

The position determination unit 1601 calculates the position in the direction along the main scanning axis 308 of the intermediate point of each light spot using L _{1 to} L _N calculated in this way. Specifically, the calculation can be performed according to the following formula, as in the fifth embodiment.
Lc _1,2 = (L ₁ + L ₂ ) / 2
Lc _2,3 = (L ₂ + L ₃ ) / 2
...
Lc _{N−1, N} = (L _N−1 + L _N ) / 2
Yc _1,2 = Lc _1,2 + Y ₀
Yc _2,3 = Lc _2,3 + Y ₀
...
_{Yc N-1, N = Lc} N-1, N + Y 0
Here, Lc _{a, a + 1} is the position detection patch from when the first edge 1701 passes through the intermediate point between the light spot a and the light spot a + 1 until the second edge 1702 reaches this intermediate point. Represents travel distance. Y _{a, a + 1} represents the distance in the direction along the main scanning axis 308 with respect to the intermediate point between the light spot a and the light spot a + 1.

  The exposure laser 102 is controlled to form the toner patch 108 so that the edge of the toner patch 108 is positioned at any position Yc of the intermediate point of the light spot detected by the above method.

As an example, a case where seven laser beams are irradiated, beams 1 to 3 are for measurement of the carrier, and beams 4 to 7 are for measurement of the toner patch 108 will be described. In this case, the toner patch 108 is formed so that the edge of the rectangular toner patch 108 is positioned at a position Yc ₃ , ₄ indicating the intermediate point of the light spots 3, ₄ and the toner patch 108 passes through the light spots 4 to 7. Is done.

As another example, a case where the beams 1, 2, 5, and 6 are used for measuring the carrier and the beams 3 and 4 are used for measuring the toner patch 108 will be described. In this case, a rectangular toner patch 108 having edges at positions Yc ₂ and ₃ indicating the intermediate point of the light spots ₂ and ₃ and positions Yc ₄ and ₅ indicating the intermediate point of the light spots ₄ and ₅ is formed. .

[Embodiment 7]
FIG. 21 shows a position detection patch according to the seventh embodiment. The position detection patch shown in FIG. 21 is a triangular patch having a first edge 2101 and a second edge 2102. Even when such a position detection patch is used, the time from when the light spot passes through the first edge 2101 until it reaches the second edge 2102 can be calculated. It is possible to detect the position of the light spot.

  According to this embodiment, since a toner image is formed between the first edge 2101 and the second edge 2102, the reflection between the first edge 2101 and the second edge 2102 due to deterioration or scratches on the carrier. It is possible to prevent a measurement error from occurring due to a change in characteristics.

[Embodiment 8]
In the first to seventh embodiments, the configuration for measuring the toner patch of the electrophotographic image forming apparatus has been described. In the eighth embodiment, a configuration for measuring the adhesion amount of a modeled object formed by a three-dimensional modeling apparatus called a 3D printer or the like will be described.

  With reference to FIG. 22, a configuration for measuring the adhesion amount of a three-dimensional modeling apparatus formed by a thin film stacking method will be described.

  Reference numeral 2200 denotes a thin-film image generation unit that receives three-dimensional data from a computer or the like (not shown) and generates thin-film transfer data based on the received three-dimensional data.

  A developing unit 2201 forms a thin-film toner image on the 2202 transfer unit based on the image.

  Reference numeral 2203 denotes a conveyance belt that conveys a 2204 transfer sheet on which a shaped article fed by the 2205 sheet feeding unit is placed. A 2206 thin film toner image is transferred from the 2202 transfer unit onto the transported transfer sheet, and then the height of the thin film toner image is measured as an adhesion amount of a modeled object by a 2207 adhesion amount measuring device.

  Reference numeral 2208 denotes a comparison unit that compares whether the measurement result is within an appropriate range.

  Reference numeral 2209 denotes a holding unit capable of holding a plurality of transfer sheets on which a thin film toner image has been transferred at a position determined in the stacking order.

  Reference numeral 2211 denotes a stacking unit that takes out the transfer sheets held in the holding unit in the order of stacking, and stacks them using the stacking pressure roller 2210.

  When measuring the height of the thin film toner image, a plurality of light sources are irradiated in a direction (main scanning) perpendicular to the conveying direction as in FIG. 3, and one side is the height of only the transfer sheet, and the other side is The height of the thin film toner image on the transfer sheet is measured. These measurement results include vibration components of a carrier such as a conveyor belt and a transfer sheet, as shown in FIG. 5, so that the accurate height of the thin film toner image can be measured by calculating the difference. .

  Based on the result of comparison between the measured value and the reference value by the comparison unit 2208, steps such as re-formation or discarding of the thin-film toner image and resetting of the forming conditions of the modeling apparatus are executed as necessary. For example, when the height of the formed thin-film toner image is lower than the reference value, the transfer belt and the holding unit are controlled so that the transfer sheet rotates around the transfer belt again, and the amount not satisfying the reference value is added. An image is generated and superimposed. When the height of the formed thin-film toner image is higher than the reference value, the formation condition of the developing unit is changed so that the thin-film toner image is discarded or the height of the output image is lowered.

101 Photosensitive drum, 106 Transfer belt, 107 Measuring device, 108 Toner image

Claims (1)

Measuring means for measuring the incident position of the light in a direction perpendicular to the surface of the carrier by irradiating light toward the carrier carrying the toner image and observing the irradiated light;
The first light incident position measured by observing the first light incident on the surface of the toner image and the second light incident on the surface of the carrier are observed simultaneously with the first light. Calculating means for calculating the thickness of the toner image based on the incident position of the second light measured by
A measuring device comprising:
The measuring means includes an irradiating means for irradiating the first light and the second light, and an observing means for observing the first light and the second light,
The irradiating means irradiates the first light and the second light at positions separated in a direction perpendicular to the toner image transport direction, and the first light and the second light are irradiated with respect to the direction perpendicular to the toner image transport direction. The measuring apparatus, wherein the irradiation directions of the first light and the second light are perpendicular to each other.