JP3862022B2 - Toner amount measuring device, measuring method, and image forming apparatus - Google Patents

Description

  The present invention relates to a toner amount measuring device, a measuring method, and an image forming apparatus.

An image forming apparatus such as a copy or printer that employs an electrophotographic system is made of toner on a recording medium such as paper through a series of image forming processes such as a charging process, an exposure process, a developing process, a transfer process, and a fixing process. An image is formed.
In the developing step, for example, charged toner is applied from the developing roller to the latent image in a state where the developing roller that carries the toner is in contact with or close to the photosensitive member that carries the electrostatic latent image, The latent image is visualized as a toner image. At this time, if the toner amount on the developing roller is not uniform within the set range in the longitudinal direction of the developing roller, the toner application amount may vary or exceed, and good development may not be performed. In order to prevent this, for example, the toner amount on the developing roller is measured at the final stage of the production line of the developing device, and it is inspected whether or not the toner amount is within a set range.

Conventionally, a method of measuring the amount of toner by using a pressure sensitive adhesive tape with a predetermined range of toner on a developing roller attached to the pressure sensitive adhesive tape and measuring the weight of the pressure sensitive adhesive tape to which the toner has adhered is generally used. Known to.
However, in this method, there is a problem that the sticking or peeling work of the adhesive tape on the developing roller is performed manually, and it takes a long time for the measurement, resulting in an increase in the cost of the product.

In addition, in this method, since the adhesive tape after measurement becomes dust, consideration for the environment is lacking.
Further, in this method, since the adhesive tape and the developing roller are in contact with each other during the measurement, the developing roller is scratched or the adhesive of the adhesive tape remains attached to the developing roller, thereby improving the image quality of the image forming apparatus. There is a possibility of lowering.

Further, when the toner amount on the developing roller is large and the layer thickness is relatively thick, it is difficult to adhere all of the developer within the target range to the adhesive tape, and it is difficult to obtain an accurate measurement result.
By the way, in addition to the above-mentioned method, as a method for measuring the amount of toner by attaching toner to a known weight, a method using a known weight nonwoven fabric is known (for example, see Patent Document 1). . Such a method also has the same problems as those described above.

JP-A-8-17920 (37th paragraph)

  SUMMARY OF THE INVENTION An object of the present invention is to provide a toner amount measuring device, a measuring method, and an image forming apparatus, which are environmentally friendly and can accurately measure the toner amount in a short time without contacting the toner carrier. is there.

The toner amount measuring apparatus of the present invention is an apparatus for measuring the amount of toner on a toner carrier that carries a toner containing a colorant in a thin layer,
Chromaticity detection means for detecting an average chromaticity of light irradiated on the toner carrier from a light source and reflected on the toner carrier;
Calculation means for calculating a toner amount based on the average chromaticity detected by the chromaticity detection means;
The chromaticity detection unit includes a charge coupled device that receives light reflected by the toner carrier, and detects chromaticity by calculating an output signal of the charge coupled device.
As a result, the light emitted from the light source onto the toner carrier is reflected by the wavelength component of chromaticity corresponding to the amount of toner on the toner carrier, and is detected by the chromaticity detection means. The calculating means can calculate the toner amount based on the average chromaticity detected by the chromaticity detecting means. As a result, the toner amount on the toner carrier can be accurately measured in a short time without contacting the toner carrier. Also, since no dust is generated during measurement, it is environmentally friendly.
In particular, the output signal of the charge coupled device can be processed to detect chromaticity, and the average chromaticity of the light reflected by the toner carrier can be detected more accurately, so that more accurate toner amount can be measured. . Further, even if the light amount of the light source is relatively small, the average chromaticity of the light reflected by the toner carrier can be detected more accurately. Therefore, a small and low-cost light source can be used.

The toner amount measuring apparatus of the present invention is an apparatus for measuring the amount of toner on a toner carrier that carries a toner containing a colorant in a thin layer,
Chromaticity detection means for detecting an average chromaticity of light irradiated on the toner carrier from a light source and reflected on the toner carrier;
Calculation means for calculating a toner amount based on the average chromaticity detected by the chromaticity detection means;
The chromaticity detecting means detects chromaticity as a tristimulus value.
As a result, the light emitted from the light source onto the toner carrier is reflected by the wavelength component of chromaticity corresponding to the amount of toner on the toner carrier, and is detected by the chromaticity detection means. The calculating means can calculate the toner amount based on the average chromaticity detected by the chromaticity detecting means. As a result, the toner amount on the toner carrier can be accurately measured in a short time without contacting the toner carrier. Also, since no dust is generated during measurement, it is environmentally friendly.
In particular, since the chromaticity is detected as a tristimulus value, the calculation means can calculate the toner amount by a relatively simple calculation method based on the average color difference.

In the toner amount measuring apparatus according to the aspect of the invention, it is preferable that the calculation unit calculates a toner amount according to a color difference between an average chromaticity detected by the chromaticity detection unit and a set chromaticity.
As a result, the calculation unit can calculate the toner amount according to the difference between the average chromaticity detected by the chromaticity detection unit and the set chromaticity. As a result, the toner amount on the toner carrier can be accurately measured in a short time without contacting the toner carrier. Also, since no dust is generated during measurement, it is environmentally friendly.
In the toner amount measuring apparatus according to the present invention, the calculating means stores a set chromaticity, a program for calculating the toner amount, and a conversion table, and the set chromaticity and the conversion table are respectively It is preferable that a plurality of settings are set corresponding to the type of toner, and the program selects a set chromaticity and conversion table corresponding to the type of toner and calculates the toner amount.
As a result, the calculation unit can calculate the toner amount according to the difference between the average chromaticity detected by the chromaticity detection unit and the set chromaticity.
In the toner amount measuring apparatus of the present invention, in the calculation means, it is preferable that the information on the type of toner includes information on the type of colorant contained in the toner.
As a result, the calculation unit can calculate the toner amount according to the difference between the average chromaticity detected by the chromaticity detection unit and the set chromaticity.

In the toner amount measuring apparatus of the present invention, the light source is preferably a white light source.
Thereby, since the average chromaticity of the light reflected by the toner carrier can be detected more accurately, a more accurate toner amount can be measured.
In the toner amount measuring apparatus of the present invention, the toner carrier is rotatably arranged, and the chromaticity detection unit scans the measurement range in the rotation axis direction of the toner carrier, It is preferable to detect the average chromaticity.
Thereby, the distribution of the toner amount in the rotation axis direction of the toner carrier can be known with a relatively simple configuration.

In the toner amount measuring apparatus of the present invention, the toner carrier is preferably a developing roller.
Thus, the amount of toner on the developing roller can be measured in a short time and accurately without being in contact with the developing roller.
In the toner amount measuring apparatus of the present invention, the toner carrier is preferably a photoconductor.
Accordingly, the amount of toner on the photoconductor can be accurately measured in a short time without being in contact with the photoconductor, which is environmentally friendly.
In the toner amount measuring apparatus of the present invention, the toner carrier is preferably a transfer body.
This makes it possible to measure the amount of toner on the transfer body in a short time and accurately without being in contact with the transfer body, which is environmentally friendly.

The toner amount measuring method of the present invention is characterized by measuring the toner amount on the toner carrier using the toner amount measuring device of the present invention.
Accordingly, the amount of toner on the toner carrier can be measured in a short time and accurately without being in contact with the toner carrier.

An image forming apparatus of the present invention is an image forming apparatus for recording an image formed by a series of image forming processes on a recording medium, and includes the toner amount measuring apparatus of the present invention.
Accordingly, the amount of toner on the toner carrier can be measured in a short time and accurately without being in contact with the toner carrier.

Embodiments of the present invention will be described below.
The present invention measures the amount of toner on a toner carrier that carries toner, and detects the average chromaticity of light irradiated on the toner carrier from a light source and reflected on the toner carrier. And a toner amount is calculated based on the average chromaticity detected by the chromaticity detection unit. Here, examples of the toner carrying member include a developing roller, a photosensitive member, and a transfer member provided in an image forming apparatus such as a copy or printer that employs an electrophotographic system. Hereinafter, prior to the toner amount measuring apparatus and method of the present invention, the configuration and operation of the image forming apparatus will be briefly described.

(Image forming device)
First, a laser beam printer (hereinafter referred to as a printer) 10 will be described as an example of an image forming apparatus with reference to FIG.
FIG. 1 is a schematic cross-sectional view showing a schematic configuration of the printer 10. In FIG. 1, the vertical direction is indicated by arrows.

  As shown in FIG. 1, the printer 10 has a photosensitive member 20 that carries a latent image and rotates in the direction of the arrow in the drawing, and sequentially, along the rotation direction, a charging unit 30, an exposure unit 40, a developing unit 50, A primary transfer unit 60, an intermediate transfer member 70, and a cleaning unit 75 are disposed. In addition, the printer 10 has a paper feed tray 92 that feeds a recording medium P such as paper at the bottom in FIG. 1, and the secondary side downstream of the paper feeding tray 92 in the conveyance direction of the recording medium P. A transfer unit 80 and a fixing unit 90 are sequentially arranged.

The photoreceptor 20 has a cylindrical conductive substrate and a photosensitive layer formed on the outer peripheral surface thereof, and is rotatable around the axis in the direction of the arrow in FIG.
The charging unit 30 is a device for uniformly charging the surface of the photoconductor 20 by corona charging or the like.
The exposure unit 40 receives image information from a host computer such as a personal computer (not shown) and irradiates a laser on the uniformly charged photoreceptor 20 to form an electrostatic latent image. It is a device to do.

  The developing unit 50 has four developing devices, a black developing device 51, a magenta developing device 52, a cyan developing device 53, and a yellow developing device 54. These developing devices are converted into latent images on the photosensitive member 20. It is an apparatus that visualizes the latent image as a toner image, selectively used correspondingly. The black developing device 51 uses black (K) toner, the magenta developing device 52 uses magenta (M) toner, the cyan developing device 53 uses cyan (C) toner, and the yellow developing device 54 uses yellow (Y) toner.

  The YMCK developing unit 50 in the present embodiment is rotatable so that the above-described four developing devices 51, 52, 53, 54 are selectively opposed to the photoconductor 20. Specifically, in this YMCK developing unit 50, four developing devices 51, 52, 53, and 54 are held by four holding portions 55a, 55b, 55c, and 55d, which are rotatable around a shaft 50a, respectively. The four developing devices 51, 52, 53, and 54 are selectively opposed to the photoconductor 20 while maintaining the relative positional relationship by the rotation of the holder. The detailed configuration of each developing device will be described later.

The primary transfer unit 60 is a device for transferring a single color toner image formed on the photoconductor 20 to the intermediate transfer body 70.
The intermediate transfer member 70 is an endless belt, and is driven to rotate in the direction of the arrow shown in FIG. On the intermediate transfer member 70, a toner image of at least one of black, magenta, cyan, and yellow is carried. For example, when a full-color image is formed, four color toner images of black, magenta, cyan, and yellow are sequentially formed. The toner images are transferred to form a full-color toner image.

The secondary transfer unit 80 is a device for transferring a single color or full color toner image formed on the intermediate transfer body 70 to a recording medium P such as paper, film, or cloth.
The fixing unit 90 is a device for fixing the toner image as a permanent image by fusing the toner image to the recording medium P by heating and pressurizing the recording medium P that has received the transfer of the toner image.
The cleaning unit 75 has a rubber cleaning blade 76 that contacts the surface of the photoconductor 20 between the primary transfer unit 60 and the charging unit 30, and a toner image is transferred onto the intermediate transfer body 70 by the primary transfer unit 60. Then, the toner remaining on the photoreceptor 20 is scraped off and removed by the cleaning blade 76.

Next, the operation of the printer 10 configured as described above will be described.
First, in response to a command from a host computer (not shown), the photosensitive member 20, a developing roller 510 (FIG. 3) provided in the developing unit 50, and an intermediate transfer member 70 start to rotate. The photoreceptor 20 is sequentially charged by the charging unit 30 while rotating.
The charged area of the photoconductor 20 reaches the exposure position as the photoconductor 20 rotates, and the exposure unit 40 forms a latent image corresponding to the image information of the first color, for example, yellow Y, in the area. .

The latent image formed on the photoconductor 20 reaches the development position as the photoconductor 20 rotates, and is developed with yellow toner by the yellow developing device 54. As a result, a yellow toner image is formed on the photoreceptor 20. At this time, in the YMCK developing unit 50, the yellow developing device 54 faces the photoconductor 20 at the developing position.
The yellow toner image formed on the photoconductor 20 reaches the primary transfer position as the photoconductor 20 rotates, and is transferred to the intermediate transfer body 70 by the primary transfer unit 60. At this time, a primary transfer voltage (primary transfer bias) having a polarity opposite to the charging polarity of the toner is applied to the primary transfer unit 60. During this time, the secondary transfer unit 80 is separated from the intermediate transfer member 70.

  By repeating the same process as the process described above for the second color, the third color, and the fourth color, the toner images of the respective colors corresponding to the respective image signals are transferred onto the intermediate transfer member 70 in an overlapping manner. The As a result, a full-color toner image is formed on the intermediate transfer member 70. On the other hand, the recording medium P is conveyed from the paper feed tray 92 to the secondary transfer unit 80 by a paper feed roller 94 and a registration roller 96.

The full-color toner image formed on the intermediate transfer body 70 reaches the secondary transfer position as the intermediate transfer body 70 rotates, and is transferred to the recording medium P by the secondary transfer unit 80. At this time, the secondary transfer unit 80 is pressed against the intermediate transfer body 70 and a secondary transfer voltage (secondary transfer bias) is applied.
The full color toner image transferred to the recording medium P is heated and pressurized by the fixing unit 90 and fused to the recording medium P.
On the other hand, after the primary transfer position has elapsed, the toner adhering to the surface of the photoconductor 20 is scraped off by the cleaning blade 76 of the cleaning unit 75 to prepare for charging for forming the next latent image. The toner that has been scraped off is collected by a residual toner collecting section in the cleaning unit 75.

(Developer)
Next, the yellow developing device 54 of the YMCK developing unit 50 will be described in detail with reference to FIG.
FIG. 2 is a schematic cross-sectional view showing a schematic configuration of the yellow developing device 54. The black developing device 51, the magenta developing device 52, and the cyan developing device 53 have the same configuration as that of the yellow developing device 54, although the toner to be used is different.
The yellow developing device 54 is carried by the developing roller 510, a housing 540 that accommodates toner T, which is yellow toner, a developing roller 510 that is a toner carrier, a toner supply roller 550 that supplies the toner T to the developing roller 510, and the developing roller 510. And a regulating blade 560 for regulating the layer thickness of the toner T.

  The housing 540 stores toner T in a storage portion 530 formed as an internal space thereof. In the housing 540, a toner supply roller 550 and a developing roller 510 are supported so as to be able to press and rotate with each other at an opening formed in the lower portion of the housing portion 530 and in the vicinity thereof. Further, the toner supply roller 550 and the regulation blade 560 are attached to the housing 540, and these are pressed against the developing roller 510. Further, a seal member 520 for preventing leakage of toner from between the housing 540 and the developing roller 510 in the opening is attached to the housing 540.

The developing roller 510 carries the toner T and conveys it to a developing position facing the photoconductor 20. The developing roller 510 is composed mainly of aluminum, stainless steel, iron or the like. Further, the surface of the developing roller 510 is subjected to nickel plating, chrome plating, sand blasting, or the like as necessary.
Further, the developing roller 510 can rotate around the axis, and in this embodiment, rotates in the direction opposite to the rotation direction of the photoconductor 20. That is, these peripheral surfaces move in the same direction at the facing portion between the developing roller 510 and the photosensitive member 20.
In this embodiment, the developing roller 510 and the photoconductor 20 face each other in a non-contact state with a minute gap during development by the yellow developing device 54. Then, an alternating electric field is applied between the developing roller 510 and the photosensitive member 20 to cause the toner T to fly from the developing roller 510 to the photosensitive member 20 for development.

  The toner supply roller 550 supplies the toner T stored in the storage unit 530 to the developing roller 510. The toner supply roller 550 is made of polyurethane foam or the like, and is pressed against the developing roller 510 in an elastically deformed state. In the present embodiment, the toner supply roller 550 rotates in the direction opposite to the rotation direction of the developing roller 510. The toner supply roller 550 not only has a function of supplying the toner T stored in the storage unit 530 to the developing roller 510, but also peels off the toner T remaining on the developing roller 510 after the development from the developing roller 510. It also has a function.

The regulating blade 560 regulates the layer thickness of the toner T carried on the developing roller 510, and applies a charge to the toner T carried on the developing roller 510 by frictional charging at the time of regulation. This regulating blade 560 also functions as a seal member on the upstream side of the developing position in the rotation direction of the developing roller 510. The regulating blade 560 includes a rubber portion 560a as a contact member that is contacted along the axial direction of the developing roller 510, and a rubber support portion 560b as a support member that supports the rubber portion 560a. . The rubber part 560a is made of silicon rubber, urethane rubber or the like as a main material, and the rubber support part 560b also has a function of urging the rubber part 560a toward the developing roller 510, so that it has spring properties such as phosphor bronze and stainless steel. A sheet-like thin plate is used. One end of the rubber support portion 560 b is fixed to the blade support metal plate 562. The blade support sheet metal 562 is attached to the housing 540. In a state where the seal member 520 is attached to the housing 540 and the developing roller 510 is further attached, the rubber part 560a is pressed against the developing roller 510 by the elastic force due to the bending of the rubber support part 560b.
In the present embodiment, a blade back member 570 is provided on the side opposite to the developing roller 510 side of the regulating blade 560 to prevent the toner T from entering between the rubber support portion 560b and the housing 540. The rubber portion 560a is pressed against the developing roller 510, and the rubber portion 560a is pressed against the developing roller 510.

  In this embodiment, the free end portion of the regulating blade 560, that is, the end portion opposite to the side supported by the blade support metal plate 562, is not contacted with the developing roller 510 at the end edge. It is in contact with the developing roller 510 at a slightly separated site. The regulating blade 560 is disposed so that the tip thereof faces the upstream side in the rotation direction of the developing roller 510, and is in a so-called counter contact.

  In the yellow developing device 54 configured as described above, the toner supply roller 550 supplies the toner T accommodated in the accommodating portion 530 to the developing roller 510. The toner T supplied to the developing roller 510 reaches the contact position of the regulating blade 560 as the developing roller 510 rotates, and the layer thickness is regulated and electric charge is applied when passing through the contact position. Is done. The toner T carried on the developing roller 510 after the regulation of the layer thickness reaches the developing position facing the photoconductor 20 by the further rotation of the developing roller 510, and the latent image on the photoconductor 20 is caused by an alternating electric field at the developing position. Used for image development. The toner T on the developing roller 510 that has passed the developing position due to further rotation of the developing roller 510 passes through the seal member 520 and is collected in the housing 540 without being scraped off by the seal member 520.

  In the developing process as described above, the toner amount on the developing roller 510 needs to be uniform over almost the entire area in the axial direction of the developing roller 510 in order to perform a good developing process. Therefore, in the present embodiment, in the development device manufacturing line, at the final stage before the development device is incorporated into the image forming apparatus, the amount of toner on the development roller of the development device alone is measured using a measurement device as described below. Measure and inspect the developing device. Here, the amount of toner on the developing roller 510 is not uniform over almost the entire area in the axial direction of the developing roller 510, and the reason why the developing device is defective as a product is that the surface of the developing roller is not uniform, the development Examples include contact failure of the regulating blade to the roller, toner charging failure by the regulating blade, and the like, and whether or not these defects are present can be inspected by a measuring device described later.

(Toner amount measuring device)
Next, the toner amount measuring apparatus 1 will be described with reference to FIG. Here, a case will be described as an example where the measuring device 1 is used to measure the amount of toner on the developing roller 510 of the yellow developing device 54 described above.
FIG. 3 is a schematic diagram showing a schematic configuration of the toner amount measuring apparatus 1 in the present embodiment.
As shown in FIG. 3, the measuring apparatus 1 includes a light source 2 that irradiates light onto a developing roller 510 that is a toner carrier that carries toner T in a thin layer, and an average chromaticity of light reflected on the developing roller 510. And a calculation device 4 that calculates a toner amount based on the chromaticity detected by the chromaticity detection device 3.

The light source 2 emits light in a wavelength region in which the chromaticity detection device 3 can detect the average chromaticity of the toner on the developing roller 510.
In the present embodiment, a xenon lamp that is a white light source is used as the light source 2. Thereby, the average chromaticity of the light reflected by the developing roller 510 can be detected more accurately. As a result, the toner amount can be measured more accurately. The white light source is not limited to a xenon lamp, and other white light sources such as a mercury lamp and a white laser can be used.

The light source 2 is not particularly limited as long as the chromaticity detection device 3 emits light having a wavelength region in which the average chromaticity of the toner on the developing roller 510 can be detected. A light source can be used.
In such light irradiated from the light source 2 to the developing roller 510, a wavelength component having a chromaticity corresponding to the amount of toner (particularly the amount of colorant) on the developing roller 510 is reflected on the developing roller 510. The light reflected on the developing roller 510 is detected by a chromaticity detection device 3 described later.

The chromaticity detection device 3 detects the average chromaticity of light reflected on the developing roller 510.
In the present embodiment, an XYZ line camera is used as the chromaticity detection device 3. This XYZ line camera has three charge-coupled devices (CCDs) corresponding to tristimulus values, arithmetically processes the output signals of these charge-coupled devices, and converts the chromaticity to tristimulus values (X, Y, Z) to be detected (tristimulus value CCD).

  If the chromaticity detection device 3 has a charge coupled device and detects the chromaticity by calculating the output signal of the charge coupled device, the average chromaticity of the light reflected by the developing roller 510 can be more accurately determined. Since it can be detected, a more accurate toner amount can be measured. In addition, even if the light amount of the light source is relatively small, the average chromaticity of the light reflected by the developing roller 510 can be detected more accurately. Therefore, the light source 2 can be made small and low cost.

If the chromaticity detection device 3 detects chromaticity as a tristimulus value, the calculation device 4 described later can calculate the toner amount by a relatively simple calculation method based on the average color difference.
The chromaticity detection device 3 is not limited to the tristimulus value CCD described above as long as it can detect the average chromaticity of the light reflected on the developing roller 510. For example, as the chromaticity detection device 3, in addition to the tristimulus value CCD, a solid-state imaging device such as a spectral CCD, a C-MOS (Complementary Metal Oxide Semiconductor), an imaging tube, or the like can be used.

The calculation device 4 obtains a difference between the average chromaticity (hereinafter referred to as detected chromaticity) detected by the chromaticity detection device 3 and the set chromaticity, and calculates the toner amount according to the difference. is there.
In the present embodiment, the calculation device 4 includes an AD conversion circuit 41, a ROM 42, a RAM 43, and a CPU 44 as shown in FIG.
The AD conversion circuit 41 converts the output value of the chromaticity detection device 3 from analog to digital.

The ROM 42 stores a difference between the detected chromaticity and the set chromaticity, a program for calculating the toner amount, a set chromaticity, a conversion table for converting the difference into the toner amount, and the like. Here, a plurality of set chromaticities and conversion tables are set corresponding to the type of toner to be measured (for example, the type of toner colorant) and are selected as appropriate.
The RAM 43 has a function of storing values calculated by programs.

  The CPU 44 calculates a difference value between the detected chromaticity digitized by the AD conversion circuit 41 and the set chromaticity stored in the ROM 42 according to the program stored in the ROM 42, and calculates the difference value based on the conversion table. Convert to In the present embodiment, the set chromaticity is fixed and set in advance in the ROM 42. However, the set chromaticity may be obtained by monitoring the light emitted from the light source 2 onto the developing roller 510.

  As described above, the light emitted from the light source 2 onto the developing roller 510 is detected by the chromaticity detection device 3 after the wavelength component of chromaticity corresponding to the toner amount on the developing roller 510 is reflected on the developing roller 510. Is done. Therefore, the difference between the detected chromaticity and the set chromaticity depends on the amount of toner on the developing roller 510. By using such a relationship between the detected chromaticity and the toner amount, the calculation device 4 can calculate the toner amount.

The toner amount calculated in this way can be visually displayed as a numerical value by a display means (not shown) such as a liquid crystal connected to the calculation device 4, for example. Thereby, the measurer can determine whether or not the measurement result is within the set reference range. Also, the difference between the calculated toner amount and the set reference value is displayed on the display unit, and whether the calculated toner amount is within the set reference range is displayed on the display unit. You can also
In the above-described measurement, it is preferable that the chromaticity detection unit 3 detects the average chromaticity while scanning the detection range in the rotation axis direction of the developing roller 510. Thereby, the distribution of the amount of toner T in the direction of the rotation axis of the developing roller 510 can be measured with a relatively simple configuration.

As described above, the calculation device 4 can calculate the amount of the toner T according to the difference between the average chromaticity detected by the chromaticity detection unit 3 and the set chromaticity. As a result, the amount of toner T on the developing roller 510 can be measured accurately in a short time without contacting the developing roller 510. Also, since no dust is generated during measurement, it is environmentally friendly.
In the above-described embodiment, the example in which the toner carrying member is the developing roller 510 has been described. However, there is no particular limitation as long as the toner carrying member is carried. For example, the photosensitive member 20 or the intermediate transfer member 70 in the above-described image forming apparatus can be used as a toner carrier, and the amount of toner carried on the surface can be measured. Alternatively, the recording medium P can be a toner carrier, and the amount of toner carried on the surface can be measured.

  In the above-described embodiment, the example in which the toner amount on the toner carrier is measured for the inspection of the product in the production line has been described. However, the toner amount measurement device is incorporated in the image forming apparatus to measure the toner amount. Various operations of the image forming apparatus can be controlled based on the measurement result of the toner amount by the apparatus. Hereinafter, an example of the control of the image forming apparatus using the toner amount measuring apparatus of the present invention will be briefly described in the case where the toner amount measuring apparatus 1 is incorporated in the printer 10.

  When the amount of toner carried on the developing roller 510 or the photoconductor 20 is measured by the toner amount measuring apparatus 1 of the present invention, for example, the developing bias can be controlled according to the measured toner amount. In this case, for example, the amount of toner flying from the developing roller 510 to the photoconductor 20 can be made constant by decreasing the developing bias as the measured toner amount increases. When measuring the toner amount on the photoconductor 20, for example, a latent image for toner amount measurement is formed in a non-sheet passing area on the photoconductor 20, and this latent image is used as a toner image. Then, the toner amount can be measured relatively easily and accurately. In particular, the present invention detects the amount of toner based on the chromaticity corresponding to the amount of colorant in the toner, so even if the amount of colorant in the toner varies among the toner particles, The amount of the colorant on the photoconductor 20 can be accurately controlled. As a result, an image obtained by the color image forming apparatus configured as described above is particularly excellent in color reproducibility with respect to input image information and the like.

  Further, when the toner amount on the intermediate transfer body 70 is measured by the toner amount measuring device 1 of the present invention, for example, the primary transfer bias and the secondary transfer bias can be controlled according to the measured toner amount. In this case, for example, as the amount of toner to be measured increases, the primary transfer bias and the secondary transfer bias are reduced to transfer from the photoconductor 20 to the intermediate transfer body 70 or from the intermediate transfer body 70 to the recording medium P. Good transferability can be maintained. Also in this case, for example, a latent image for toner amount measurement is formed in a non-sheet passing region on the photoconductor 20, and this latent image is used as a toner image, which is transferred onto the intermediate transfer member 70. When measured, the toner amount can be measured relatively easily and accurately.

  Further, the fixing conditions in the fixing unit 90 can be controlled in accordance with the measured toner amount in at least one of the developing roller 510, the photoconductor 20, the intermediate transfer member 70, and the recording medium P. For example, as the amount of measured toner increases, the heating temperature of the fixing roller provided in the fixing unit 90 is increased, the pressure contact force between the fixing roller and the pressure roller is increased, or the conveyance speed of the recording medium P is decreased. For example, the fixing result can be kept good.

Next, examples of the present invention will be described.
The amount of toner reflected on the developing roller of each of the yellow, magenta, cyan, and black developing devices configured as shown in FIG. 3 was measured using the toner amount measuring device configured as shown in FIG. .
At this time, a xenon lamp was used as the light source, and an XYZ line camera (XL-S, Kurabo Industries Co., Ltd.) that is a tristimulus CCD was used as the chromaticity detection device. Each color toner was produced by kneading and pulverization using polyester and a colorant as materials, and the average particle size was 8.5 μm. As a colorant for each toner, a non-benzine pigment was used for yellow toner, a carmine pigment was used for magenta toner, a copper phthalocyanine pigment was used for cyan toner, and carbon black was used for black toner. In these toners, silica and titania were used as external additives.
The measurement was performed on two types of developing devices (developing devices 1 and 2) having different toner amounts on the developing roller in each of the developing devices of yellow, magenta, cyan, and black.

Table 1 shows the measurement results of the toner amount of the developing roller of each developing device. Table 1 also shows the L, a, b values (Hunter Lab system) based on the output values (tristimulus values X, Y, Z) from the XYZ line camera, and the color difference between these values and the set chromaticity. Show.
As a reference example, using a pressure sensitive adhesive tape (Sumitomo 3M Co., Ltd.) having a width of 12 mm × a length of 275 mm square and a known weight, after the measurement in the example, the toner amount in the same part as the example for the developing roller of each developing device Table 1 also shows the results of careful measurement of.

As shown in Table 1, the color difference has a relationship according to the measured toner amount of the reference example. In this example, by using a conversion table having such a relationship, a result equivalent to that carefully measured using an adhesive tape was obtained. As described above, when the toner amount measuring apparatus of the present invention is used, the toner amount on the developing roller can be measured very accurately. Further, since the toner amount measuring apparatus of the present invention measures the toner amount in a non-contact manner with respect to the developing roller, the developing roller is not damaged, and the measuring time is also a measuring method using an adhesive tape. In comparison, it is extremely short.
For the photosensitive member, the intermediate transfer member, and the recording medium, the amount of toner carried on the photosensitive member, the intermediate transfer member, and the recording medium was measured in the same manner as in the above-described example, and as in the example, the toner amount could be measured satisfactorily. .

1 is a schematic cross-sectional view illustrating a schematic configuration of an image forming apparatus according to an embodiment. FIG. 2 is a diagram illustrating a schematic configuration of a developing device provided in the image forming apparatus of FIG. 1. 1 is a diagram illustrating a schematic configuration of a toner amount measuring apparatus according to an exemplary embodiment.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Toner amount measuring device 2 ... Light source 10 ... Printer (image forming device) 20 ... Photoconductor 3 ... Chromaticity detection device (chromaticity detection means) 30 ... Charging unit 4 ... Calculation device (calculation means) 40 ... Exposure unit 41 ... AD conversion circuit 42 ... ROM 43 ... RAM 44 ... CPU 50 ... Development unit 50a ... Axis 51 Black development device 52 Magenta development device 53 Cyan development device 54 Yellow development device 55a to 55d Holding unit 510 Development roller 520 Seal member 530 ············································································································· Rubber Holding plate 570 ... Blade back member 60 ... Primary transfer unit 70 ... Intermediate transfer body 75 ... Cleaning unit 76 ... Cleaning blade 80 ... Secondary transfer unit 90 ... Fixing unit 92 Paper feed tray 94 ... Paper feed roller 96 ... Registration roller P ... Recording medium T ... Toner

Claims (12)

An apparatus for measuring the amount of toner on a toner carrier for carrying a toner containing a colorant in a thin layer,
Chromaticity detection means for detecting an average chromaticity of light irradiated on the toner carrier from a light source and reflected on the toner carrier;
Calculation means for calculating a toner amount based on the average chromaticity detected by the chromaticity detection means;
The chromaticity detection unit includes a charge coupled device that receives light reflected by the toner carrier, and detects the chromaticity by calculating the output signal of the charge coupled device. Quantity measuring device. An apparatus for measuring the amount of toner on a toner carrier for carrying a toner containing a colorant in a thin layer,
Chromaticity detection means for detecting an average chromaticity of light irradiated on the toner carrier from a light source and reflected on the toner carrier;
Calculation means for calculating a toner amount based on the average chromaticity detected by the chromaticity detection means;
The toner amount measuring device, wherein the chromaticity detection means detects chromaticity as a tristimulus value.   The toner amount measuring apparatus according to claim 1, wherein the calculating unit calculates a toner amount according to a color difference between an average chromaticity detected by the chromaticity detecting unit and a set chromaticity.   The calculating means stores a set chromaticity, a program for calculating a toner amount, and a conversion table, and a plurality of the set chromaticities and the conversion table are set corresponding to the type of toner. 4. The toner amount measuring apparatus according to claim 3, wherein the program selects a set chromaticity and a conversion table corresponding to a toner type and calculates a toner amount.   5. The toner amount measuring apparatus according to claim 4, wherein in the calculation means, the information on the type of toner includes information on the type of colorant contained in the toner.   6. The toner amount measuring apparatus according to claim 1, wherein the light source is a white light source.   2. The toner carrier is rotatably arranged, and the chromaticity detection unit detects the average chromaticity while scanning a measurement range in a rotation axis direction of the toner carrier. 7. The toner amount measuring apparatus according to any one of items 6 to 6.   The toner amount measuring apparatus according to claim 1, wherein the toner carrier is a developing roller.   The toner amount measuring device according to claim 1, wherein the toner carrier is a photosensitive member.   The toner amount measuring apparatus according to claim 1, wherein the toner carrier is a transfer body.   11. A toner amount measuring method, comprising: measuring a toner amount on a toner carrier using the toner amount measuring device according to claim 1; An image forming apparatus for recording an image formed by a series of image forming processes on a recording medium, comprising the toner amount measuring device according to claim 1.

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