JP2006220472A - Adhesion measuring device of powder - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an adhesion measuring device of powder capable of measuring non-electrostatic adhesion of different powder substances to each other by using a centrifugation method having a relatively simple principle and easy to quantify without limiting types of powder. <P>SOLUTION: This adhesion measuring device of powder is provided with a centrifuge having a rotor installable so that a vertical line of a sample surface of a sample substrate with one layer of particles of one kind of material to be attached uniformly fixed thereto is set vertical to its rotating shaft, and is used for measuring non-electrostatic powder-to-powder adhesion between powder comprising at least one kind of fine particles and the particles of the material to be attached on the sample substrate by centrifugal force generated by the rotation of the centrifuge. The adhesion measuring device is characteristically provided with a spin coat device for uniformly applying an adhesive for fixing the particles to be attached by rapidly rotating the sample substrate. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a powder adhesion measuring apparatus for measuring the adhesion between powders, and more particularly to a powder adhesion measuring apparatus for toners and carriers used in the field of electrophotography.

  Understanding various characteristics of powder is important in image formation using electrophotography. There are many characteristics of powder, such as repose angle, cohesion, and dispersion. Adhesion is one of the important factors involved in high-quality image formation, especially in the electrophotographic process. As the process progresses, the measurement of non-electrostatic adhesion that is sensitive to the environment has been regarded as important. In general, for example, a centrifugal separation method is known as a method for measuring the adhesion of powder (see, for example, Patent Document 1).

  In addition, as another method, there is one using an ultrasonic standing wave (see, for example, Patent Document 2).

  In addition, there is one using a means for separating from an adherend using vibration (for example, see Patent Document 3).

  In addition, there is one using a means for separating from an adherend using an electric field (see, for example, Patent Document 4).

  Among them, the method using centrifugal force is relatively easy to quantify as compared with other methods.

  These mainly relate to the adhesion between the toner, which is powder, and the photosensitive member, the metal substrate, and the like, and also relate to measurement means specialized in the adhesion between the toner and the carrier (for example, see Non-Patent Document 1).

  In this document, the toner is sprinkled on a fixed carrier when measuring the non-electrostatic adhesion force between the toner and the carrier. Thus, the adhesion force of the carrier cannot be measured, and there is a fear that the adhesion force between the toner aggregate and the carrier may be obtained. In addition, if the separation of the toner from the carrier can be observed while rotating the rotor, it is possible to correctly observe the toner particle diameter. It becomes impossible to confirm whether it was separated every time. Since the estimation of the toner adhesion force is performed based on the particle size of the toner after separation, there is a possibility that the toner particle size at the time of separation cannot be accurately observed.

  On the other hand, since the toner particles have variations in particle diameter, surface shape, and the like, it is expected that the adhesion force acting between the toner carriers is distributed. Since such distribution spread affects image formation, it is more preferable to obtain such information. For example, although it is not a centrifugal method, the method for measuring the adhesion force described in Patent Document 3 shows a method in which the adherend of fine particles is vibrated and collected by an electric field, and the adhesion force is estimated from its mass. In order to measure the influence of the electric field on the adhesion force due to the vibration of the electrode and the amount of fine particles as mass, the analysis is limited to the average analysis, and the distribution of the adhesion force of the toner alone is measured. There is a risk of not being able to.

  On the other hand, a powder comprising a mixture of at least one magnetic particle and one or more fine particles is magnetically attached to an object carrier having a uniform object-bearing surface. While applying a constant electric field to the body, the carrier is moved at high speed in the direction perpendicular to the carrying surface, the fine particles are desorbed from the magnetic particles, and the number of particles before and after desorption and the mass of the particles are obtained. There is also a method for measuring the adhesive force between fine particles, which is characterized by measuring the adhesive force (see Patent Document 5).

Japanese Patent Application Laid-Open No. 10-276772 JP 2002-310892 A JP-A-11-153538 JP 2001-228075 A JP 2003-098065 A Yutaka Fukuchi, 5 others, "Factors involved in toner adhesion" JapanHardCopy '97, Proceedings of the Electrophotographic Society, July 9, 1997, p.81-84

  However, in this case, since the method of fixing particles is magnetically fixed, it can be used only for magnetic particles such as carriers, and there is a more versatile measurement method for particles other than magnetic particles. More preferred.

  From the above, the principle is relatively simple, and there has been no sufficient measurement for non-electrostatic adhesion between different powders using a centrifugal method that is easy to quantify.

  The present invention has been made in view of the above-mentioned problems. The object of the present invention is not limited to the type of powder, and the powder is different using a centrifugal method that is relatively simple in principle and easy to quantify. An object of the present invention is to provide a powder adhesion measuring device capable of measuring the non-electrostatic adhesion between each other.

  In order to achieve the above object, the present invention provides a centrifugal separator having a rotor that can be installed so that a perpendicular to the sample surface of the sample substrate on which one kind of adherend particles are uniformly fixed is perpendicular to the rotation axis. A non-electrostatic adhesion force between the powder composed of at least one kind of fine particles and the adherend material particles on the sample substrate with a centrifugal force generated by the rotation of the centrifugal separator. The powder adhesion measuring apparatus is characterized by comprising a spin coater for uniformly applying an adhesive for rotating the sample substrate at a high speed and fixing the particles to be adhered.

  According to the present invention, the non-electrostatic adhesion force between different powders can be measured using a centrifugal method that is relatively simple in principle and easy to quantify without limiting the type of powder. .

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

  FIG. 1 is a schematic view of an adhesive force measurement sample according to the present invention.

  The adhesive 2 is uniformly applied to the sample substrate 1, and the adherend material particles 3 (hereinafter referred to as particles 3) are more uniformly fixed, and one particle or more of powder 4 composed of one or more kinds of fine particles is formed thereon. Each is attached independently. FIG. 2 is a diagram illustrating a process for preparing the adhesion force measurement sample. In this embodiment, the particle 3 is a color complex machine iRC3200 manufactured by Canon Inc., the powder 4 is a color toner for electrophotography, and the color is cyan.

  The sample preparation process includes an adhesive application process 5, an adherend fixing process 6, and a particle adhesion process 7. FIG. 3 is a schematic view showing the adhesive application step 5.

The adhesive 2 is uniformly applied to the sample substrate 1 using the spin coater 8. The spin coater 8 is composed of a motor 10 for rotating a base 9, a power supply device 11, and a cover 12 for preventing the adhesive from scattering. Adhesive 2 is an epoxy resin adhesive, and “Cemedine High Super 5” was used in the present embodiment. The tensile shear bond strength of the adhesive used is 20 (N / mm ² ) or more when the maximum rotational speed of the centrifugal separator used is 100,000 (rpm). When the adhesive strength is not sufficient at 20 N / mm ² or less, it is not preferable because the entire adhesion surface is separated from the sample substrate when centrifugation is performed.

The tensile shear bond strength of the adhesive of the present embodiment was 24.0 (N / mm ² ). The sample substrate 1 is fixed to the base 9 of the spin coater, and the adhesive 2 is dropped while rotating at a high speed to produce a uniform and thin layer. Adhesive thickness must be smaller than the average particle size of particles 3 and is buried in the adhesive layer and cannot be measured. Therefore, pay sufficient attention to rotation time, adhesive viscosity, and adhesive curing time. Cost.

  In the present embodiment, the viscosity of the main agent is 150 (Pa · S / 20 ° C.) and the curing agent is 75 (Pa · S / 20 ° C.). When rotated at about 10,000 rpm, 45 μm in 30 seconds, A film thickness of 20 to 25 μm was reached in 60 seconds, and the film pressure hardly changed even when a longer time was taken. If the curing time is too early, curing begins during spin coating, and the particles 3 cannot be completely fixed. In addition, if it takes too much time to start curing, the productivity is lowered. In the present embodiment, the carrier used has an average particle size of 35 μm, and the adhesive was cured by rotating at about 10,000 rpm for 60 seconds to a thickness of about 20 μm and fixing the carrier to the sample substrate 1.

  After applying the adhesive, the process proceeds to the adherend fixing process 6. The sample substrate 1 is removed from the base 9, and the particles 3 are sprinkled on the adhesive layer before the adhesive is cured. The adhesive is completely cured in a pile as much as possible, that is, until the maximum strength is reached. In this embodiment, 24 hours have passed. Thereafter, as shown in FIG. 4, the sample substrate 1 is placed in the folder 14 so that the perpendicular of the sample surface of the sample substrate 1 is perpendicular to the rotation axis 17 on the rotor 13 for centrifugation. A receiving substrate 15 is placed through a hollow central portion such as a spacer 16 so as to be parallel to the substrate 1, and a sufficient number of revolutions is given to the rotor 13. In this case, it is preferable to give the maximum rotation speed of the centrifuge to be used.

  The centrifuge used in this embodiment is CP100MX manufactured by Hitachi Koki (maximum rotational speed: 100,000 rpm, maximum centrifugal acceleration 803,000 × g), and the rotor is an angle rotor P100AT manufactured by Hitachi Koki (maximum rotational speed: 100000 rpm, A maximum centrifugal acceleration of 803,000 × g) was used. It is possible to remove excess particles 3 that are not in contact with the adhesive 2 by the centrifugal force generated by the centrifugal separation, and prevent the powder 4 from adhering to the sample substrate when the centrifugal separation is performed. Can do.

  Calculation of the magnitude of the centrifugal force will be described later.

  After removing the excess particles 3, the particle adhesion step 7 is reached. In this step, an operation of attaching the powder 4 to the sample substrate 1 on which the particles 3 are sufficiently fixed is performed. It should be noted here that since the desired adhesion force is the force between the particles 3 and the powder 4, if the powder 4 is agglomerated, it is determined whether the toner is separated alone during the centrifugation. The particle size varies depending on whether the particles are separated, and if the particle size is determined by estimation without knowing the state of separation, the value may be different from the desired value.

  Therefore, vibration is used for particle adhesion. FIG. 5 is a schematic view of the particle adhesion step 7. The powder 4 is placed on the vibration device 18, and the fixing base 20 on which the sample substrate 1 on which the particles 3 are fixed is attached upside down is placed on the support column 19, and vibration is applied. By applying vibration, the powder 4 is slightly in a cloud state, and becomes independent. Since it adheres to the sample substrate 1 in that state, it becomes possible to create a sample in which the powder 4 is individually independent, and the amount of adhesion can be adjusted by adjusting the height and time of the column 19. In addition, since the powder etc. which are easy to be charged will be easily charged when vibration is given for a long time, it must be attached in a short time. In the present embodiment, an ultrasonic generator is used as the vibration device 18 and is hardly charged if it adheres within 1 to 2 minutes.

  The above is the method for producing the measurement sample. Next, the method for calculating the adhesive force using the centrifugal separation method is entered.

  FIG. 6 shows an operation process for a method for calculating the adhesion between powders. The method for measuring the adhesion force between powders includes a centrifugal separation step 21, an image collection step 22, an image analysis step 23, and an adhesion force calculation step 24. As shown in FIG. 4, the substrate 1 and the receiving substrate 15, which are the measurement samples prepared, are perpendicular to the rotation axis 17 with respect to the rotor 13 for centrifugation through the spacer 16. In this manner, the rotor 13 is rotated. At this time, a one-point mark or the like is put in advance on the substrate 1 and the receiving substrate 15 so that the orientation is always matched when the folder 1 is put.

  Further, it is preferable to make the distance between the receiving substrate 15 and the measurement sample substrate closer. In this embodiment, it is 2 mm. This is because after the powder 4 is separated from the particles 3 during the centrifugal separation, the powder 4 does not go completely in the vertical direction but tends to go in the direction slightly opposite to the rotational direction.

When the centrifuge is driven and the rotor is rotated, the powder in the measurement cell receives a centrifugal force corresponding to the size and mass of the powder. A schematic diagram is shown in FIG. Fa is adhesive force, Fc is centrifugal force (centrifugal
force). The powder 4 on the measurement sample surface receives a centrifugal force corresponding to the number of rotations, and when the centrifugal force acting on the powder 4 becomes larger than the adhesion force on the measurement sample surface, the receiving substrate 15 receives from the measurement sample surface. The powder 4 moves. The centrifugal force received by the particles of mass m (kg) is expressed by the equation (1) using the rotational speed f (rpm) of the rotor and the distance r (m) from the rotary shaft 17 to the powder 4 on the measurement sample substrate. ).

F = m × r × (2πf / 60) ² (1)
Here, the mass m (kg) of the powder is obtained by the equation (2) using the true specific gravity ρ (kg / m 3) and the equivalent circle diameter d (m).

m = (4π / 3) × ρ × (d / 2) ³ (2)
In the centrifugal separation step 21, the receiving substrate 15 is changed at every constant rotation speed. In this case, the number of rotations of the rotor of the sample to be measured is determined so that the size of each particle of the powder 4 on the receiving substrate 15 can be reliably recognized, that is, the powders 4 overlap each other. Must be independent so that they do not. This is because the adhesive force cannot be estimated unless the particle size of the powder 4 can be measured accurately. In other words, since there was a possibility that toner that had been independent before separation would overlap due to toner movement while adhering to the receiving substrate at the time of separation, the rotation section was determined finely and received each time. It is preferable to change the substrate 15.

  In order to facilitate the image collection step 22 and the image analysis step 23, it is preferable to apply a material having a uniform surface to the substrate. In this measurement, cast coated paper was used. A metal such as aluminum is easily affected by light, and a paper having rough fibers is not preferable because toner enters the fibers and images cannot be captured well.

  The centrifugal separation step 21 changes the rotation number from a low rotation number to a high rotation number, and after changing the receiving substrate 15 at each rotation number, the image collection step 22 is entered.

  The image collecting step 22 is a step of collecting the powder 4 image on the receiving substrate 15. The powder 4 can be independently attached to the sample substrate 1 in the particle attaching step 7, but there are toners or the like that enter the shadow of the carrier, and it is difficult to accurately grasp the state of the sample substrate 1, so the amount of attachment can be reduced. It is difficult to accurately quantify from changes in the sample substrate 1. Therefore, it is necessary to calculate the adhesion force from the separated powder 4 of the receiving substrate 15 instead of calculating the adhesion force from the change in the amount of adhesion on the measurement sample substrate for each rotation speed.

  Therefore, in the present measurement method, as described above, the sample substrate 1 and the receiving substrate 15 are marked in advance, and the powder 4 is separated from the receiving substrate 15 and the measuring sample substrate by centrifuging them in the same direction. Since the locations to be connected have a corresponding relationship, it is possible to obtain the amount of separation of the powder 4 from the substrate. This becomes more accurate as the distance between the receiving substrate 15 and the measurement sample substrate is shorter, and the deviation in the horizontal direction of the substrate is almost negligible.

  Needless to say, repeating the measurement increases the accuracy from the reproducibility.

  The image collection is performed using an optical microscope and a photographing means for photographing an image of the powder on the receiving substrate obtained through the optical microscope. At that time, if a sample fixing table or the like is designed for the sample table and the receiving substrate 15 is placed on the fixed table and the image is taken in, an image of the separated powder 4 from a predetermined position on the measurement sample substrate is obtained. Can be collected.

  And the image collection process 22 is complete | finished by taking in the image of all the receiving boards for each rotation speed.

  Next, an image analysis process 23 for extracting information on the powder 4 using the captured image is performed. Here, for all the captured images, the equivalent circle diameter of the powder 4 on the image is extracted using image processing software. Most image processing software has functions such as binarization or color extraction, so that it can be processed without much trouble. At this time, if there is a lot of roughness on the receiving substrate, the image processing is relatively time-consuming and correction is required. Therefore, the material having a uniform surface is attached to the receiving substrate 15 as described above. And preferred. In the present embodiment, cyan toner is extracted using image processing software WinRoof, and the equivalent circle diameter of each toner is obtained.

  The final adhesion calculation operation is performed using the equivalent circle diameter of the powder taken out in the image analysis step 23.

  By substituting the equivalent circle diameter (m) and the rotation speed (rpm) taken out in the above formulas (1) and (2) and the true specific gravity ρ of the powder 4, the powder 4 per grain Can be calculated. In this embodiment, the value of the adhesion force is the value of the centrifugal force with respect to the rotational speed of the rotor 13 in the adhesion force measurement when the toner is separated and the rotor 13 in the previous adhesion force measurement in which the toner is not separated. The average value of the centrifugal force with respect to the number of rotations was defined as the value of the adhesion force of the toner. The above is the means for calculating the adhesion force of each powder 4.

  Therefore, an adhesion distribution is created by taking the common logarithm values of the estimated individual adhesion forces. FIG. 8 is a distribution diagram obtained from common logarithmic values of the adhesive force in the embodiment. The number distribution is displayed with the adhesive force on the horizontal axis and the frequency on the vertical axis. From the result of the adhesive force distribution, it was confirmed that there was a tendency in the adhesive force, and it was distributed in a wide range. When the obtained adhesive force distribution was statistically processed to calculate the average adhesive force, the non-electrostatic adhesive force was calculated to be about 3.5 nN with an average of two samples.

  By performing the above-described series of operations, it is possible to measure the non-electrostatic adhesion force between the powder composed of at least one kind of fine particles and the particles on the sample substrate.

  As described above, the non-electrostatic adhesion force between the electrophotographic toner and the carrier was calculated using the present invention while describing the embodiment. However, the present invention is not limited to these embodiments, and various powders are used. Non-electrostatic adhesion between bodies can be determined.

It is an image figure of the adhesive force measurement sample which concerns on this invention. It is a figure which shows the preparation process of a sample. It is the figure which showed the adhesive agent application process. It is the figure which showed the schematic diagram inside the rotor of a centrifuge. It is the figure which modeled the particle adhesion process. It is a figure which shows the operation | work process about the adhesive force calculation method between powder. It is a figure which shows the outline of the principle of the centrifugation method. It is a figure which shows the result of the adhesive force distribution of an Example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Sample board | substrate 2 Adhesive agent 3 Adhering material particle | grains 4 Powder which consists of one or more types of fine particles 8 Spin coat device 9 Base 10 Motor 11 Power supply device 12 Cover 13 Rotor 14 Folder 15 Receiving substrate 16 Spacer 17 Rotating shaft 18 Vibrating device 19 Strut 20 Fixing base 25 Distance between the rotating shaft and powder on the measurement sample substrate

Claims (7)

A centrifuge having a rotor that can be installed so that a perpendicular of the sample surface of the sample substrate on which one kind of adherent material particles are uniformly fixed is perpendicular to the rotation axis; and by rotating the centrifuge In a powder adhesion measuring apparatus for measuring a non-electrostatic adhesion force between a powder consisting of at least one kind of fine particles and a powder to be adhered on the sample substrate with a generated centrifugal force,
An apparatus for measuring adhesion of powder, comprising: a spin coater that uniformly rotates an adhesive that fixes the particles to be adhered by rotating the sample substrate at a high speed. One type of adhesive for fixing particles used in the spin coater has a tensile shear adhesive strength of 20 (N / mm 2).
2) Adhesive force measurement of powder according to claim 1.   3. The powder adhesive force measuring apparatus according to claim 1, wherein an epoxy resin adhesive is used as the adhesive.   A powder composed of one or more kinds of fine particles on the sample substrate is non-electrostatically attached to the adherent material particles on the sample substrate by using vibration without causing the powder to have an electric charge. The powder adhesive force measuring apparatus according to claim 1.   A receiving substrate that can receive powder composed of at least one kind of fine particles on the sample substrate separated by centrifugal force in the centrifugal separator and can be placed in parallel with the sample substrate; 2. The adhesion force of the powder composed of at least one kind of fine particles is calculated using the particle size and specific gravity of the separated powder and the rotational speed of the rotor at the time of separation from the sample substrate. The powder adhesive force measuring apparatus as described.   6. The powder adhesive force measuring apparatus according to claim 1, wherein an average adhesive force is calculated from an adhesive force distribution of at least one kind of fine particles separated from the sample substrate.   2. An optical microscope, a photographing means for photographing an image of the powder on the receiving substrate obtained through the optical microscope, and an image processing means for obtaining a particle diameter of the powder from the powder image. Item 6. The apparatus for measuring adhesion of powder according to Item 5.

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