JP2000181153A - Image forming device and method for detecting toner stuck quantity thereon - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make toner stuck quantity to be more appropriately detected, regardless of the presence of uneven gloss on the toner image carrier surface, without exerting adverse influence thereon. SOLUTION: This device is allowed to detect the ranges Δ of variance of output voltage of the toner image carrier by measuring the output voltage over one peripheral portion in accordance with a reflecting light quantity of the toner image carrier itself prior to the toner stuck quantity detection. Thereafter, in the actual toner stuck quantity detecting time, the device is allowed to detect the output voltage Vs corresponding to the reflecting light quantity from the toner image based on the gradation pattern formed on the toner image carrier by a light receiving element, however, by detecting the toner stuck quantity in specifying the range of the output voltage Vs so as to exclude the range Δ of variance of the output voltage, the toner stuck quantity being hardly influenced by the variance of the output voltage is detected.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus such as a color printer for forming an image by using a toner image carrier such as a photoreceptor or an intermediate transfer member, and a method for detecting the amount of toner attached thereto.

[0002]

2. Description of the Related Art Conventionally, in this type of color printer, etc., gamma correction for converting the number of gradations of input image data into the number of writing gradations of output so as to obtain a desired image gamma characteristic is performed. In order to perform the operation properly, a predetermined pattern toner image is formed on an image carrier, and the amount of toner adhesion is detected based on an output voltage obtained by detecting the amount of reflected light with a light receiving element. In this case, the pattern toner image is formed as a toner image with a gradation pattern in which the gradation per dot is continuous in the traveling direction (rotation direction) of the toner image carrier.

Here, the relationship between the output voltage of the light receiving element and the toner adhesion amount is as shown in FIG. 9 (a), since the regular reflection light is detected in the case of black toner, so that the toner adhesion amount is "0". The graph shows a downward-sloping graph characteristic in which the output voltage becomes the highest and decreases as the amount of adhesion increases. On the other hand, in the case of the color toner, as shown in FIG. 9B, the output voltage becomes the lowest when the toner adhesion amount is “0”, and shows a graph characteristic that rises to the right and increases as the adhesion amount increases. Assuming that the output voltage when the toner adhesion amount is “0” is Vst, this output voltage Vst is the intermediate transfer belt (or
It means an output voltage due to light reflected from the surface of the photosensitive member.

[0004]

However, due to individual differences of the intermediate transfer belt (or the photosensitive member) and differences in reflection characteristics due to aging, the surface of the intermediate transfer belt (or the photosensitive member) has a glossy surface during one rotation. Unevenness may occur and the output voltage Vst may vary. In particular, in the case of detecting the toner adhesion amount of the black toner for detecting the regular reflection light, the influence is large.
In other words, when detecting the adhesion amount of a portion of the gradation pattern where the toner adhesion amount is low, when there is uneven gloss on the surface of the toner image carrier, the amount of reflected toner due to the uneven gloss = the variation in output voltage, the toner adhesion amount is correctly detected. Failures that cannot be made may occur. As a result, correct gamma correction cannot be performed, and inconveniences such as inconsistency in the density of an image particularly in a highlight portion occur.

Accordingly, the present invention provides an image forming apparatus and a toner adhesion amount detecting method capable of detecting the adhesion amount of toner more properly without being affected by uneven gloss even on the surface of the toner image carrier. The purpose is to provide.

[0006]

According to the first aspect of the present invention,
A toner image is formed on a toner image carrier by a gradation pattern in which the density is continuously changed in accordance with the rotation direction, and the toner image is formed by an output voltage obtained from a light receiving element corresponding to the amount of reflected light from the toner image. In the method for detecting the amount of toner adhered to an image forming apparatus, the amount of toner adhered is detected by the light receiving element and the output voltage corresponding to the amount of light reflected from the surface of the toner image carrier for one round is detected before the amount of toner adhered is detected. The range of variation is detected by measuring over a range, and the effective range of the output voltage obtained from the light receiving element based on the toner image based on the gradation pattern when the amount of toner adhesion is detected is specified in accordance with the variation range to determine the toner adhesion amount. Was detected.

Therefore, prior to the detection of the amount of adhered toner, the output voltage corresponding to the amount of reflected light of the toner image carrier itself is measured over one rotation to detect the range of variation in the output voltage of the toner image carrier. Since the effective range of the output voltage at the time of detecting the toner adhesion amount is specified and the toner adhesion amount is detected so as to exclude such a variation range, it is possible to detect the toner adhesion amount with little influence of the output voltage variation. .
The toner adhesion amount corresponding to the output voltage outside the effective range may be complemented by, for example, data continuously connected by a straight line having a preset slope.

According to a second aspect of the present invention, a toner image is formed on a toner image carrier according to a gradation pattern in which the density is continuously changed in accordance with the direction of rotation of the toner image carrier, and light is received corresponding to the amount of reflected light from the toner image. In the toner adhesion amount detection method of the image forming apparatus, wherein the toner adhesion amount of the toner image is detected based on an output voltage obtained from an element, prior to the toner adhesion amount detection, the light receiving element detects the toner adhesion amount from the surface of the toner image carrier. The output voltage corresponding to the amount of reflected light is measured over one round to detect the minimum value, and the maximum value of the effective range of the output voltage obtained from the light receiving element based on the toner image based on the gradation pattern when detecting the amount of adhered toner. The value is specified according to the minimum value to detect the amount of toner adhesion.

Therefore, the output voltage corresponding to the amount of reflected light of the toner image carrier itself is measured over one rotation prior to the detection of the toner adhesion amount, so that the minimum value of the output voltage of the toner image carrier = the variation range Since the lower limit is detected and the effective range of the output voltage at the time of detecting the toner adhesion amount is specified according to the minimum value to detect the toner adhesion amount, it is possible to detect the toner adhesion amount with little influence of the output voltage variation. Become. In addition,
The toner adhesion amount corresponding to the output voltage out of the effective range may be complemented by, for example, data continuously connected by a straight line having a preset slope.

According to a third aspect of the present invention, a toner image is formed on a toner image carrier according to a gradation pattern in which the density is continuously changed in accordance with the direction of rotation, and light is received in accordance with the amount of reflected light from the toner image. In the toner adhesion amount detection method of the image forming apparatus, wherein the toner adhesion amount of the toner image is detected based on an output voltage obtained from an element, prior to the toner adhesion amount detection, the light receiving element detects the toner adhesion amount from the surface of the toner image carrier. The output voltage corresponding to the amount of reflected light is measured over one round to detect the variation range, and the effective range of the output voltage obtained from the light receiving element is determined based on the toner image based on the gradation pattern when the amount of adhered toner is detected. Specified according to the variation range, detect the toner adhesion amount, and enable the toner adhesion amount outside the effective range of the output voltage And to calculate on the basis of the output voltage of 囲内.

Therefore, prior to the detection of the amount of adhered toner, the output voltage corresponding to the amount of reflected light of the toner image carrier itself is measured over one turn, thereby detecting the variation range of the output voltage of the toner image carrier. Since the effective range of the output voltage at the time of detecting the toner adhesion amount is specified and the toner adhesion amount is detected so as to exclude such a variation range, it is possible to detect the toner adhesion amount with little influence of the output voltage variation. .
Further, the toner adhesion amount corresponding to the output voltage outside the effective range is calculated by a polynomial regression method or the like based on the output voltage within the effective range. The detection of the proper amount of toner adhesion is performed.

According to a fourth aspect of the present invention, there is provided a toner image carrier, a light emitting element for irradiating the toner image carrier with light,
A light receiving element for receiving light reflected from the toner image carrier based on the light emitted by the light emitting element, and a gradation pattern in which the density is continuously changed on the toner image carrier according to the rotation direction when the amount of toner adhered is detected. A pattern toner image forming unit for forming a toner image, and an output voltage obtained from the light receiving element corresponding to a reflected light amount from the toner image formed by the pattern toner image forming unit. An image forming apparatus comprising:
Prior to the detection of the amount of adhered toner, a toner image carrier inspection means for measuring an output voltage corresponding to the amount of light reflected from the surface of the toner image carrier by the light receiving element over one round and detecting a variation range thereof; A detection effective range specifying unit that specifies an effective range of an output voltage obtained from the light receiving element based on the toner image based on the gradation pattern when detecting the toner adhesion amount, according to the variation range.

Therefore, prior to the detection of the toner adhesion amount, the output voltage corresponding to the amount of reflected light of the toner image carrier itself is measured over one round by the toner image carrier inspection means, so that the output voltage of the toner image carrier is measured. Detect the variation range of
Since the effective range of the output voltage at the time of detecting the toner adhesion amount is specified and the toner adhesion amount is detected by the detection effective range specifying means so as to exclude such a variation range, the toner adhesion amount having little influence of the output voltage variation is reduced. Can be detected. The toner adhesion amount corresponding to the output voltage outside the effective range may be complemented by, for example, data continuously connected by a straight line having a preset slope.

According to a fifth aspect of the present invention, there is provided a toner image carrier, a light emitting element for irradiating the toner image carrier with light,
A light receiving element for receiving light reflected from the toner image carrier based on the light emitted by the light emitting element, and a gradation pattern in which the density is continuously changed on the toner image carrier according to the rotation direction when the amount of toner adhered is detected. A pattern toner image forming unit for forming a toner image, and an output voltage obtained from the light receiving element corresponding to a reflected light amount from the toner image formed by the pattern toner image forming unit. An image forming apparatus comprising:
Prior to the toner adhesion amount detection, a toner image carrier inspection means for measuring an output voltage corresponding to the amount of light reflected from the toner image carrier surface by the light receiving element over one rotation and detecting a minimum value thereof; Detection effective range specifying means for specifying the maximum value of the effective range of the output voltage obtained from the light receiving element based on the toner image based on the gradation pattern when detecting the amount of adhered toner, according to the minimum value.

Therefore, the output voltage of the toner image carrier is measured by measuring the output voltage corresponding to the amount of reflected light of the toner image carrier over one round by the toner image carrier inspection means prior to the detection of the toner adhesion amount. Minimum value = variable range is detected and the effective range of the output voltage at the time of detecting the toner adhesion amount is detected by the effective range identifying means according to this minimum value to detect the toner adhesion amount. This makes it possible to detect the amount of toner adhesion that is less affected by variations. The toner adhesion amount corresponding to the output voltage outside the effective range may be complemented by, for example, data continuously connected by a straight line having a preset slope.

According to a sixth aspect of the present invention, there is provided a toner image carrier, and a light emitting element for irradiating the toner image carrier with light;
A light receiving element for receiving light reflected from the toner image carrier based on the light emitted by the light emitting element, and a gradation pattern in which the density is continuously changed on the toner image carrier according to the rotation direction when the amount of toner adhered is detected. A pattern toner image forming unit for forming a toner image, and an output voltage obtained from the light receiving element corresponding to a reflected light amount from the toner image formed by the pattern toner image forming unit. An image forming apparatus comprising:
Prior to the detection of the toner adhesion amount, an image carrier inspection means for measuring an output voltage corresponding to the amount of light reflected from the surface of the toner image carrier by the light receiving element over one rotation and detecting a variation range thereof, Detection effective range specifying means for specifying an effective range of an output voltage obtained from the light receiving element based on the toner image based on the gradation pattern at the time of detecting the amount of adhesion in accordance with the variation range; And a toner adhesion amount calculation unit that calculates based on the output voltage within the effective range.

Therefore, the output voltage of the toner image carrier is measured by measuring the output voltage corresponding to the amount of reflected light of the toner image carrier over one round by the toner image carrier inspection means prior to the detection of the toner adhesion amount. Detect the variation range of
Since the effective range of the output voltage at the time of detecting the toner adhesion amount is specified and the toner adhesion amount is detected by the detection effective range specifying means so as to exclude such a variation range, the toner adhesion amount having little influence of the output voltage variation is reduced. Can be detected. Further, the toner adhesion amount corresponding to the output voltage out of the effective range is calculated by the toner adhesion amount calculating means by a polynomial regression method or the like based on the output voltage in the effective range, and thus has a variation outside the effective range. More appropriate detection of the amount of adhered toner than in the case of the output voltage.

[0018]

FIG. 1 shows a first embodiment of the present invention.
A description will be given with reference to FIG. First, a configuration example of a full-color printer using an electrophotographic process as an image forming apparatus to which the toner adhesion amount detection method of the present invention is applied will be described with reference to FIG. First, there is provided a belt-shaped photosensitive member 3 rotatably supported by the rotating rollers 1 and 2 and driven to rotate in the direction of arrow A. A charging device 4, a discharging lamp 5, and a cleaning blade 6 are arranged in this order around the photoreceptor 3, and a laser writing unit including a laser light source, a laser scanning optical system, and the like is located downstream of the charging device 4. The light writing position by the laser light emitted from 7 is set. A color developing device 8 is provided downstream of the optical writing position. The color developing device 8 has a revolver structure including a yellow developing device, a magenta developing device, and a cyan developing device for each color of toner to be stored. A black developing device 9 containing black toner is provided downstream of the color developing device 8.
Any one of the developing units and the black developing unit 9 in the color developing device 8 moves to a position where development can be performed on the photoconductor 3 in synchronization with the development timing of the corresponding color.

Further, on the downstream side of the developing position, the photosensitive member 3
An intermediate transfer belt 10 as a toner image carrier that is in contact with is supported by rotating rollers 11 and 12 so as to be rotatable in the direction of arrow B. The intermediate transfer belt 10 receives the transfer of the toner image on the photoreceptor 3 by the action of the bias means 13 on the back side. That is, the photoconductor 3 is cleaned by the cleaning blade 5 for each color, and a toner image of a predetermined color is sequentially formed.
The image is transferred to the same position on the intermediate transfer belt 10 every one rotation of the intermediate transfer belt 10, whereby a color toner image in which a plurality of color toners are superimposed on the intermediate transfer belt 10 is formed.
The toner image formed on the intermediate transfer belt 10 is transferred by a transfer roller 15 onto a recording medium 14 such as paper or plastic fed and conveyed at a predetermined timing.

In the printer, an electric device / control device 16 is provided.
Is built-in. A CPU 17 and a storage element 18 (see FIG.
In FIG. 2, for convenience, it is shown extracted). The CPU 17 can execute the functions of a pattern toner image forming unit, a toner adhering amount detecting unit, a toner image carrier inspecting unit, and a detection effective range specifying unit, which will be described later, according to a program stored in advance.

Further, in the present embodiment, a reflection-type detection element 19 is provided so as to closely approach a part of the outer peripheral surface of the intermediate transfer belt 10. The detecting element 19 is provided at a position corresponding to a toner image based on a gradation pattern formed by the pattern toner image forming means, and emits light toward the surface of the intermediate transfer belt 10 such as an LED (not shown). And a light receiving element (not shown) such as a photodiode for receiving the reflected light from the intermediate transfer belt 10 side.

In such a configuration, basically, as in the prior art, before starting the image forming operation, the number of gradations of the input image data is adjusted so that the target image γ characteristic is obtained. In order to properly perform γ correction for converting to a tone, the pattern toner image forming means
A toner image is formed by a gradation pattern in which the gradation per dot is continuous in the traveling direction (rotation direction) of the intermediate transfer belt 10, and the amount of toner adhesion is detected based on an output voltage obtained by detecting the amount of reflected light with a light receiving element. To detect the amount of toner adhesion.

Here, the relationship between the output voltage of the light receiving element for detecting the toner adhesion amount of the pattern toner image formed on the intermediate transfer belt 10 and the toner adhesion amount is shown in FIG.
(A) and (b) are as described above. Accordingly, due to individual differences of the intermediate transfer belt 10 and differences in reflection characteristics due to aging, gloss unevenness may occur on the surface during one round of the intermediate transfer belt 10 and the output voltage Vst may vary. In particular, in the case of detecting the toner adhesion amount of the black toner for detecting the regular reflection light, the influence is large. That is, when there is uneven gloss on the surface of the intermediate transfer belt 10 at the time of detecting the amount of toner adhesion in the portion of the gradation pattern where the amount of toner is low, the amount of toner adhesion is correctly detected based on the variation in the amount of reflected light due to the uneven gloss = the variation in the output voltage. Failures that cannot be made may occur. As a result, correct gamma correction cannot be performed, and inconveniences such as inconsistency in the density of an image particularly in a highlight portion occur.

Therefore, in the present embodiment, prior to the detection of the amount of adhered toner, an output obtained corresponding to the amount of light reflected from the surface of the intermediate transfer belt 10 over one rotation of the intermediate transfer belt 10 by the light receiving element in the detection element 19. The voltage Vst is measured, the variation range Δ thereof is detected and stored in the storage element 18. Then, when the actual amount of toner adhesion is detected, a toner image is formed on the intermediate transfer belt 10 by a gradation pattern, and the toner image is formed. The toner adhesion amount is detected by specifying the effective range of the output voltage obtained from the light receiving element according to the reflected light amount according to the variation range Δ stored in the storage element 18.

FIG. 2 shows an example of the result of measurement of the output voltage Vst obtained corresponding to the amount of light reflected from the surface of the intermediate transfer belt 10 over one rotation of the intermediate transfer belt 10 by the light receiving element prior to the detection of the amount of adhered toner. Has a certain variation range Δ. On the other hand, FIG. 3 shows how the output voltage obtained from the light receiving element changes in accordance with the amount of reflected light from the toner image due to the gradation pattern formed on the intermediate transfer belt 10 when the actual amount of attached toner is detected. That is, there is a relationship between the number of write gradations and the detection voltage (output voltage) Vs.
Using this relationship, the number of gradations of the input image data is converted into the number of writing gradations of the output so as to obtain the target image γ characteristic. At this time, since the portion where the toner adhesion amount is small is affected by the variation of the output voltage Vs, the portion belonging to the variation range Δ of the output voltage Vs detected in advance is out of the effective range as shown in FIG. The toner adhering amount is detected based on the output voltage Vs detected using a portion that does not belong to the variation range Δ as an effective range. Also,
The portion outside the effective range is obtained by complementing the data of the portion by continuing the effective range with a straight line having a preset slope.

FIG. 4 is a flowchart showing an example of such processing executed under the control of the CPU 17. In advance,
The variation range Δ is measured by detecting the output voltage Vst for one rotation of the intermediate transfer belt 10 (step S).
1). The processing in step S1 is executed as a function of the toner image carrier inspection means. Next, in order to detect the actual amount of adhered toner, a toner image is formed by a gradation pattern on the intermediate transfer belt 10 through the photoconductor 3 by the pattern toner image forming means, and the reflected light is received by the light receiving element. Obtain the output voltage Vs (S
2). With respect to the output voltage Vs detected in this manner, the portion belonging to the variation range Δ detected in step S1 is excluded from the effective range, thereby specifying the effective range and detecting the toner adhesion amount (S3). ). The process of step S3 is executed as a function of the detection effective range specifying unit. Thereafter, for the portion outside the effective range, the data is complemented to detect the toner adhesion amount (S4).

Therefore, according to the present embodiment, the intermediate transfer belt 10 has the output voltage Vst corresponding to the amount of reflected light of the intermediate transfer belt 10 itself for one rotation before detecting the toner adhesion amount. Output voltage variation range Δ
Is detected, and the effective range of the output voltage Vs at the time of detecting the toner adhesion amount is specified to detect the toner adhesion amount so as to exclude such a variation range Δ. Therefore, the toner adhesion is less affected by the variation in the output voltage Vst. The amount can be detected.
Further, the toner adhesion amount corresponding to the output voltage Vs out of the effective range is detected based on the complemented data.

The gray scale number data of the portion outside the effective range may be calculated based on the output voltage within the effective range. FIG. 5 shows an example of the processing, in which data outside the effective range is calculated using data within the effective range (S5).
The process of step S5 is executed as a function of the toner adhesion amount calculation means. More specifically, for example, it may be calculated by a polynomial regression method using a plurality of data in the effective range and in the vicinity of the portion where the toner adhesion amount is small.

A second embodiment of the present invention will be described with reference to FIGS. The same portions as those described in the first embodiment are denoted by the same reference numerals, and description thereof is omitted.
Basically, it is the same as the first embodiment, but in this embodiment, prior to detecting the amount of toner adhering, the amount of light reflected from the surface of the intermediate transfer belt 10 over one rotation by the light receiving element. Is measured and the minimum value A thereof is detected and stored in the storage element 18.
Thereafter, when detecting the actual amount of adhered toner, a toner image is formed on the intermediate transfer belt 10 by a gradation pattern, and the maximum value of the effective range of the output voltage obtained from the light receiving element according to the amount of reflected light from the toner image is stored. Element 1
The toner adhering amount is detected by specifying according to the minimum value A stored in 8.

FIG. 6 shows an example of the result of measurement of the output voltage Vst obtained corresponding to the amount of light reflected from the surface of the intermediate transfer belt 10 over one rotation of the intermediate transfer belt 10 by the light receiving element prior to the detection of the toner adhesion amount. It can be seen that the minimum value is A. On the other hand, FIG. 7 shows how the output voltage obtained from the light receiving element changes in accordance with the amount of reflected light from the toner image due to the gradation pattern formed on the intermediate transfer belt 10 when the actual amount of attached toner is detected. At this time, since the portion where the toner adhesion amount is small is affected by the variation of the output voltage Vs, the portion belonging to the region larger than the previously detected minimum value A of the output voltage Vs is, as shown in FIG. Outside the effective range, the minimum value A is set as the maximum value, and the lower part is set as the effective range, and the toner adhesion amount is detected based on the output voltage Vs detected. In addition, the portion outside the effective range is obtained by complementing the data of the portion by connecting the straight line with a preset slope to the effective range.

FIG. 8 is a flowchart showing an example of such processing executed under the control of the CPU 17. In advance,
The minimum value A is measured by detecting the output voltage Vst for one rotation of the intermediate transfer belt 10 (step S1). The processing in step S1 is executed as a function of the toner image carrier inspection means. Next, in order to detect the actual amount of adhered toner, the photosensitive member 3 is
To form a toner image with a gradation pattern on the intermediate transfer belt 10, and the reflected light is received by a light receiving element to obtain an output voltage Vs (S2). With respect to the output voltage Vs detected in this way, a portion that is equal to or more than the minimum value A detected in step S1 is outside the effective range,
The toner adhesion amount is detected by specifying the minimum value A as the maximum value and specifying the portion below the maximum value as the effective range (S6). The process of step S6 is executed as a function of the detection effective range specifying unit. Thereafter, for the portion outside the effective range, the data is complemented to detect the toner adhesion amount (S
7).

Therefore, according to the present embodiment, the output voltage of the intermediate transfer belt 10 is measured by measuring the output voltage corresponding to the amount of reflected light of the intermediate transfer belt 10 over one rotation before detecting the toner adhesion amount. The minimum value of the voltage A = the lower limit of the variation range is detected, and the effective range of the output voltage at the time of detecting the toner adhesion amount is specified in accordance with the minimum value A to detect the toner adhesion amount. It is possible to detect the toner adhesion amount with little influence. Further, the toner adhesion amount corresponding to the output voltage Vs out of the effective range is detected based on the complemented data.

In these embodiments, an intermediate transfer belt 10 is provided in addition to the photoreceptor 3.
Although an example in which 0 is a toner image carrier has been described, the present invention can be similarly applied to an image forming apparatus without the intermediate transfer belt 10 and using only a photoconductor as a toner image carrier.

[0034]

According to the first and fourth aspects of the present invention, the output voltage corresponding to the amount of reflected light of the toner image carrier itself is measured over one round prior to the detection of the amount of toner adhesion, whereby the toner image carrier is measured. Detect the variation range of the output voltage of the body,
Since the effective range of the output voltage at the time of detecting the toner adhesion amount is specified and the toner adhesion amount is detected so as to exclude such a variation range, it is possible to detect the toner adhesion amount with little influence of the output voltage variation. .

According to the second and fifth aspects of the present invention, the output voltage corresponding to the amount of reflected light of the toner image carrier itself is measured over one round prior to the detection of the amount of adhered toner, so that the toner image carrier can be measured. The minimum value of the output voltage has = the lower limit of the variation range is detected, and the effective range of the output voltage when the toner adhesion amount is detected is specified according to the minimum value to detect the toner adhesion amount. This makes it possible to detect the amount of toner adhesion with a small amount.

According to the third and sixth aspects of the present invention, the output voltage corresponding to the amount of reflected light of the toner image carrier itself is measured over one round prior to the detection of the amount of toner adhered, so that the toner image carrier can be measured. The range of the output voltage variation is detected, and the effective range of the output voltage at the time of toner adhesion amount detection is specified and the toner adhesion amount is detected so as to exclude such a variation range. It is possible to detect a small amount of toner adhesion.

[Brief description of the drawings]

FIG. 1 is a vertical sectional front view showing a configuration example of a color printer according to a first embodiment of the present invention.

FIG. 2 is a graph of a measurement result showing a state of variation of an output voltage based on light reflected from an intermediate transfer belt surface.

FIG. 3 is a graph of a measurement result showing an output voltage based on light reflected from a toner image by a gradation pattern.

FIG. 4 is a flowchart illustrating an outline of a toner density detection process.

FIG. 5 is a flowchart illustrating an outline of a toner density detection process according to a modified example.

FIG. 6 is a graph of a measurement result showing a state of variation of an output voltage based on light reflected from an intermediate transfer belt surface according to the second embodiment of the present invention.

FIG. 7 is a graph of a measurement result showing an output voltage based on light reflected from a toner image by a gradation pattern.

FIG. 8 is a flowchart illustrating an outline of a toner density detection process.

FIG. 9 is a graph showing an output voltage corresponding to a toner adhesion amount.

[Explanation of symbols]

 10 Toner image carrier

Claims (6)

[Claims] An output voltage obtained from a light receiving element corresponding to the amount of reflected light from a toner image is formed on a toner image carrier by a gradation pattern in which the density is continuously changed according to the rotation direction of the toner image. In the method for detecting the amount of toner attached to the toner image of the image forming apparatus, the output corresponding to the amount of light reflected from the surface of the toner image carrier by the light receiving element prior to the detection of the amount of toner attached The voltage is measured over one round to detect a variation range thereof, and an effective range of an output voltage obtained from the light receiving element is specified according to the variation range based on the toner image based on a gradation pattern when detecting the amount of adhered toner. A method for detecting the amount of toner attached to the image forming apparatus. 2. A toner image according to claim 1, wherein a toner image is formed on a toner image carrier by a gradation pattern in which the density is continuously changed in accordance with a rotation direction of the toner image. In the method for detecting the amount of toner attached to the toner image of the image forming apparatus, the output corresponding to the amount of light reflected from the surface of the toner image carrier by the light receiving element prior to the detection of the amount of toner attached The voltage is measured over one rotation to detect the minimum value, and the maximum value of the effective range of the output voltage obtained from the light receiving element based on the toner image based on the gradation pattern at the time of detecting the toner adhesion amount is set to the minimum value. A method for detecting the amount of toner adhered to an image forming apparatus, wherein the method detects the amount of toner adhered in a specified manner. 3. A toner image is formed on a toner image carrier according to a gradation pattern in which the density is continuously changed according to the rotation direction, and an output voltage obtained from a light receiving element corresponding to the amount of reflected light from the toner image. In the method for detecting the amount of toner attached to the toner image of the image forming apparatus, the output corresponding to the amount of light reflected from the surface of the toner image carrier by the light receiving element prior to the detection of the amount of toner attached The voltage is measured over one round to detect a variation range thereof, and an effective range of an output voltage obtained from the light receiving element is specified according to the variation range based on the toner image based on a gradation pattern when detecting the amount of adhered toner. To detect the amount of toner adhesion, and to determine the amount of toner adhesion outside the effective range of the output voltage based on the output voltage within the effective range. Toner adhesion amount detecting method of the image forming apparatus is characterized in that to calculate come. 4. A toner image carrier, a light emitting element for irradiating the toner image carrier with light, a light receiving element for receiving reflected light from the toner image carrier side based on light emitted by the light emitting element, and a toner A pattern toner image forming means for forming a toner image based on a gradation pattern in which the density is continuously changed in accordance with the rotation direction on the toner image carrier at the time of detecting the amount of adhesion, and the toner formed by the pattern toner image forming means An image forming apparatus comprising: a toner adhering amount detecting unit that detects a toner adhering amount of the toner image based on an output voltage obtained from the light receiving element in accordance with an amount of reflected light from an image. The output voltage corresponding to the amount of reflected light from the surface of the toner image carrier is measured by the light receiving element over one round, and the variation range is measured. A toner image carrier inspection means for detecting, and a detection effective range specifying means for specifying an effective range of an output voltage obtained from the light receiving element based on the toner image based on a gradation pattern at the time of toner adhesion amount detection according to the variation range, An image forming apparatus comprising: 5. A toner image carrier, a light emitting element for irradiating light on the toner image carrier, a light receiving element for receiving reflected light from the toner image carrier side based on light emitted by the light emitting element, and a toner. A pattern toner image forming means for forming a toner image based on a gradation pattern in which the density is continuously changed in accordance with the rotation direction on the toner image carrier at the time of detecting the amount of adhesion, and the toner formed by the pattern toner image forming means An image forming apparatus comprising: a toner adhering amount detecting unit that detects a toner adhering amount of the toner image based on an output voltage obtained from the light receiving element in accordance with an amount of reflected light from an image. The output voltage corresponding to the amount of reflected light from the surface of the toner image carrier is measured by the light receiving element over one round, and the minimum value is detected. Toner image carrier inspection means, and detection effective range identification means for identifying the maximum value of the effective range of the output voltage obtained from the light receiving element based on the toner image based on the gradation pattern when detecting the amount of applied toner in accordance with the minimum value An image forming apparatus comprising: 6. A toner image carrier, a light emitting element for irradiating the toner image carrier with light, a light receiving element for receiving reflected light from the toner image carrier side based on light emitted by the light emitting element, and a toner. A pattern toner image forming means for forming a toner image based on a gradation pattern in which the density is continuously changed in accordance with the rotation direction on the toner image carrier at the time of detecting the amount of adhesion, and the toner formed by the pattern toner image forming means An image forming apparatus comprising: a toner adhering amount detecting unit that detects a toner adhering amount of the toner image based on an output voltage obtained from the light receiving element in accordance with an amount of reflected light from an image. The output voltage corresponding to the amount of reflected light from the surface of the toner image carrier is measured by the light receiving element over one round, and the variation range is measured. Image carrier inspecting means for detecting, effective detection range specifying means for specifying an effective range of an output voltage obtained from the light receiving element based on the toner image based on a gradation pattern at the time of toner adhesion amount detection according to the variation range, An image forming apparatus comprising: a toner adhesion amount calculating unit that calculates a toner adhesion amount outside a voltage effective range based on an output voltage within the effective range.