JPH05232010A - Method and device for evaluating dispersion state of functional particulate in toner - Google Patents

Abstract

PURPOSE:To quantitatively evaluate the dispersion state of functional particulates by obtaining the particle size distribution of the functional particulates from the image signal in which the image of molten toner has been picked up. CONSTITUTION:A television camera 2 picks up the image of molten toner that has been magnified for example 1000 times, and a monochrome image signal is sent to an image processor 3. The processor 3 divides it into for example a large number of image element matrices, and binarize them by a given threshold value in accordance with the density of the image, and both the number of regions in which image elements corresponding to the dense part of the image continue, and the numbers of image elements in respective regions are sent to a computer 4 as measurement data. The computer 4 calculates an evaluation value by the calculation formula that has been previously prepared for evaluating the dispersion state of the toner and by the data sent from the processor 3. The result of the calculation is output by an output device 5.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is for evaluating the dispersion state of a functional fine powder when a toner is manufactured through a kneading step in which a functional fine powder such as a pigment or a charge control agent is dispersed in a resin. Method and apparatus.

[0002]

2. Description of the Related Art As a technique for evaluating the dispersion state of functional fine powder in a toner, there is one disclosed in Japanese Patent Laid-Open No. 61-122543. This is to evaluate the dispersion state of the functional fine powder by elongating the molten toner into a thin film and observing the thin film piece with a transmission microscope.

Further, after the toner is made into a state of a finished product which can be used by an electrophotographic copying machine, a test chart is copied onto a light-transmitting sheet using the toner, and the toner is fixed on the light-transmitting sheet. It is also performed that the difference between the maximum value and the minimum value of the spectral transmittance is measured as transparency, and the higher the transparency, the better the dispersion state.

[0004]

When thinning the molten toner and observing it with a transmission microscope, there is a problem that the evaluation of the dispersion state cannot be quantitatively evaluated because it is judged by the naked eye.

Further, when the dispersion state is evaluated based on the transparency, it is necessary to put the toner in a finished state so that the toner can be fixed on the transmission type sheet by the electrophotographic copying machine. Therefore, there is a problem that the dispersion state cannot be evaluated in the kneading step of dispersing the functional fine powder in the resin, and the evaluation result of the dispersion state cannot be fed back to the control system of the kneading step.

An object of the present invention is to provide a method and an apparatus for evaluating the dispersed state of functional fine powder in a toner, which can solve the above-mentioned problems of the prior art.

[0007]

The method of the present invention is characterized in that, when a toner is manufactured through a kneading step of dispersing a functional fine powder in a resin, an image of a molten toner is picked up,
The point is that the image signal is processed to obtain the particle size distribution of the functional fine powder particles, and the dispersion state of the functional fine powder is evaluated from the particle size distribution. In this case, the image signal of the molten toner is binarized according to the density of the image, the number of functional fine powder particles and each particle size are obtained from the binarized signal, and the function is based on the obtained number of particles and each particle size. It is preferable to obtain an evaluation value of the dispersed state of the fine powdery particles.

The device of the present invention is characterized in that it is provided with means for picking up the image of the molten toner and means for processing the image signal to obtain the particle size distribution of the functional fine powder particles in the molten toner. In this case, the image signal of the molten toner is binarized according to the lightness and darkness of the image, and a means for obtaining the number of functional fine powder particles and each particle size from the binarized signal, and based on the obtained number of particles and each particle size It is preferable to include means for calculating an evaluation value of the dispersion state of the functional fine powder particles.

[0009]

Function: A large amount of functional fine powder particles having a small particle size are present in the resin so that the kneading for dispersing the functional fine powder in the resin is sufficiently performed. On the other hand, if the resin and the functional fine powder are not sufficiently kneaded, the number of particles of the functional fine powder having a small particle size will decrease. Therefore, the dispersed state of the functional fine powder can be evaluated by imaging the molten toner during kneading and processing the image signal to obtain the number of functional fine powder particles and each particle size, that is, the particle size distribution.

In the image of the molten toner, the resin portion is thin and the functional fine powder portion is dark. Therefore, by binarizing the image signal according to the shade of the image and processing it, the number of images of the functional fine powder particles can be increased. Each image area can be obtained. Since the image area of each functional fine powder particle corresponds to the particle size, the particle size distribution of the functional fine powder can be obtained.

[0011]

Embodiments of the present invention will be described below with reference to the drawings.

The toner dispersion state evaluation apparatus shown in FIG.
The optical microscope 1, a television camera 2 that captures an image magnified by the optical microscope 1, an image processing device 3 that processes an image signal sent from the television camera 2, and the image processing device 3 are controlled. A computer 4 for calculating an evaluation value of the toner dispersion state based on the data sent from the image processing device 3 and an output device 5 for outputting the evaluation result by the computer 4 are provided. The magnification of the optical microscope 1 is 1000 times in this embodiment. The television camera 2 sends a monochrome image signal to the image processing device 3 in this embodiment. In this embodiment, the image processing device 3 divides the image into a matrix of a large number of pixels, binarizes the image signal by a constant threshold value according to the shading of the image,
The number of regions in which pixels corresponding to a dark portion of an image are continuous and the number of pixels in each region are sent to the computer 4 as measurement data. The computer 4 stores an arithmetic expression prepared in advance for evaluating the toner dispersion state, and calculates an evaluation value based on the arithmetic expression and the data sent from the image processing apparatus 3. The output device 5 is composed of a monitor and a printer for displaying the calculation result of the computer 4.

Using the above dispersion state evaluation device, the following Table 1
The three types of cyan toners A, B, and C shown in (4) were evaluated. A biaxial extrusion kneader (PCM-45 type manufactured by Ikegai Tekko KK) was used for kneading the resin and the functional fine powder.

[0014]

[Table 1]

The procedure for evaluating the dispersed state of the functional fine powder is shown in FIG.
It will be described based on the flowchart shown in FIG.

First, a toner to be evaluated was heated on a slide glass to melt it, and another cover glass was placed on the toner to extend it into a thin film to prepare an evaluation sample (step 1).

Next, the evaluation sample was measured by the optical microscope 1 to 10
The image was magnified 00 times, the enlarged image was captured by the television camera 2, and the image signal was input to the image processing device 3 (step 2).

Next, the image processing apparatus 3 converts the image signal into 2
Labeled by digitizing. In this embodiment, the image is 6
The image signal was binarized by recognizing the lightness difference of four gradations and setting the lightness of 50% as the threshold value (step 3). That is, the magnified image of the fused toner is displayed by the image processing device 3 in FIG.
As shown in (1) of FIG. 1, the molten toner is divided into a matrix of a large number of pixels, and the resin 6 portion of the molten toner is light and the functional fine powder particles 7 are
Since the portion is dark, it is converted into a binary image as shown in (2) of FIG.

Next, the number of functional fine powder particles and each area were obtained from the binarized signal, and the particle size distribution was obtained based on the obtained number of particles and each particle area (step 4). That is, by scanning the binary image, the number of regions 7'where the pixels corresponding to the functional fine powder particle 7 portion are continuous,
The number of pixels in each area 7'is obtained. The number of regions corresponds to the number of functional fine powder particles 7, the number of pixels in each region 7'corresponds to the image area of each functional fine powder particle 7, and the image area corresponds to that of each functional fine powder particle 7. Corresponds to grain size.

Next, the number of functional fine powder particles obtained based on the image processing in step 4 and the measurement data corresponding to each particle size were stored in the storage device of the computer 4 (step 5).

Next, the visual field of the evaluation sample by the optical microscope 1 was changed, and the above steps 2 to 5 were repeated to obtain measurement data for a total of 10 visual fields (step 6).

Next, the computer 4 calculates an evaluation value (step 7). In this example, based on each image area S of the functional fine powder particles, a virtual particle diameter D when each particle is assumed to be spherical is calculated from the following equation.

D = 2 × (S / π) ^1/2

The number of particles whose virtual particle diameter D is 1 μm or less is N
The evaluation value H of the dispersed state of the functional fine powder was determined by the following equation, where a is the total number of measured particles and N is the number. The evaluation value H was output by the output device 5 (step 8).

H = Na / N

The evaluation value H obtained above and the transparency described in the prior art are shown in Table 1 above, and the relationship between the evaluation value H and the transparency is shown in FIG. From this, it was confirmed that the evaluation value H and the transparency have a correlation, and that the dispersion state of the functional fine powder can be quantitatively evaluated according to the present invention.

The present invention is not limited to the above embodiment. For example, the particle size distribution of the functional fine powder may be obtained by performing a gradation image processing. In particular,
The two-dimensional image of the fused toner is divided into a matrix of a large number of pixels, and the brightness of pixels adjacent to each other in the column direction is sequentially compared. Then, since the resin portion of the molten toner is light and the functional fine powder particle portion is thick, the brightness difference or the brightness ratio becomes a certain value or more due to the decrease in the brightness, and the brightness difference or the brightness ratio becomes a constant value due to the increase in the brightness. The parts up to the above can be labeled as the functional fine powder particle parts of the row. By performing the lightness comparison for each column in the same manner, the number of regions in which pixels corresponding to the functional fine powder particle portion are continuous, that is, the number of functional fine powder particles, and the number of pixels in each region, that is, each functional fine powder The particle size of the particles can be determined. According to this grayscale image processing, there is an advantage that the number and the particle size of the functional fine powder particles can be obtained by the relative value of the lightness.

In the case of color toner, it may be difficult to distinguish the toner particles from the resin portion only by the lightness. Therefore, the toner particles may be identified from the color image according to the hue to evaluate the dispersion state. Specifically, assuming that the hue of the color toner particles is C, the hues of the three primary color components of red, green, and blue are R, G, and B, respectively, and the shade intensities of the three primary color components are x, y, and z. The hue C is expressed by the following equation.

C = xR + yG + zB

Therefore, first, an image of the fused color toner is picked up by a color video camera, the image signal is input to an image processing apparatus, and it is decomposed into three primary color components, which are stored in different memories for each component. That is, in the red component memory R ', the red image component is stored as a matrix of a large number of pixels according to the intensity of light and shade, and similarly, in the memory G'for the green component, a large number of green image components according to the intensity of light and shade is stored. The pixel B is stored as a matrix of pixels, and the blue component memory B ′ stores a blue image component as a matrix of a large number of pixels according to the intensity of light and shade.

Next, the hue Co of the color toner particles to be evaluated is set to have a certain width as follows. The hue Co has a certain width because it is difficult to accurately detect the hue Co as the constant value C.

Co = (x1 to x2) R + (y1 to y2) G + (z1 to z2) B

Next, from the pixels stored in the red component memory R ', those having a gray scale intensity of x1 to x2 are extracted,
From the pixels stored in the green component memory G ′, y1 to y2
Of the pixels having the intensity of z and z2 are extracted from the pixels stored in the memory B'for the blue component.

Next, the portion represented by the product R "∩G" ∩B "of the set R" of the extracted red image component pixels, the set G "of the green image component pixels and the set B" of the blue image component pixels. Are labeled as color toner particle portions to be evaluated. Thereby, the number of regions where the labeled pixels are continuous, that is, the number of color toner particles, and the number of pixels in each region, that is, the particle size of each color toner particle can be obtained.

[0035]

According to the method of the present invention, the dispersion state of the functional fine powder in the toner can be quantitatively evaluated in the kneading step of the resin and the functional fine powder, and the evaluation result is fed back to the control system of the kneading step. For example, the functional fine powder can be well dispersed by controlling the temperature of the supplied resin, the screw rotation speed of the kneading machine, the toner retention time in the kneading machine, and the like. According to the device of the present invention, the method of the present invention can be carried out.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of a configuration of a distributed state evaluation device according to an embodiment of the present invention.

FIG. 2 is a flowchart showing a distributed state evaluation procedure according to the embodiment of this invention.

FIG. 3 is an explanatory diagram of image processing according to the embodiment of this invention.

FIG. 4 is a diagram showing a relationship between a dispersion state evaluation value and transparency.

[Explanation of symbols]

 2 TV camera 3 Image processing device

Claims (4)

[Claims] 1. When manufacturing a toner through a kneading step of dispersing a functional fine powder in a resin, an image of a molten toner is picked up and an image signal thereof is processed to obtain a particle size distribution of the functional fine powder particle. A method for evaluating the dispersion state of functional fine powder in a toner, characterized by evaluating the dispersion state of functional fine powder from particle size distribution. 2. The image signal of the molten toner is binarized according to the density of the image, the number of functional fine powder particles and each particle size are obtained from the binarized signal, and the obtained number of particles and each particle size are used. The method for evaluating the dispersion state of functional fine powder in a toner according to claim 1, wherein an evaluation value of the dispersion state of functional fine powder is obtained based on the above. 3. A functional fine powder in a toner, comprising: a means for picking up an image of the molten toner; and a means for processing an image signal thereof to obtain a particle size distribution of the functional fine powder particles in the molten toner. Distributed state evaluation device. 4. A means for binarizing an image signal of a molten toner in accordance with the lightness and darkness of an image, and a means for finding the number of functional fine powder particles and each particle size from the binarized signal, and the obtained number of particles and each particle size. 4. A dispersion state evaluation device for functional fine powder in toner according to claim 3, further comprising means for calculating an evaluation value of the dispersion state of the functional fine powder particles.