JPH11237327A - Method and device for measuring adhesion force of fine particle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make measurable a electrostatic adhesion force and a non- electrostatic adhesion force. SOLUTION: After a fine particle is allowed to adhere to a supporting substrate 21 from a sample substrate where the fine particle is allowed to adhere by a centrifugation device, a gas is blown from a nozzle 29 by a compressor 32, a fine particle on the supporting substrate 21 is separated, the amount of electric charge on the supporting substrate is measured by an electric charge measuring device 28. By obtaining the amount of electric charge per fine particle from the number of fine particles adhering to the adhesion surface of the supporting substrate 21 that is measured in advance and the amount of electric charge, the relationship between the amount of electric charge and the adhesion force is obtained and the electrostatic adhesion force and the nonstatic adhesion force of the fine particle can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and a device for measuring powder adhesion, and more particularly to a method and a device for measuring powder adhesion used in electrophotography. .

[0002]

2. Description of the Related Art In the field of handling powder, it is important to grasp various characteristic values of the powder. One of the characteristic values of the powder is an adhesive force between the powder and an object to which the powder is attached. As a method of measuring the adhesive force of the powder, a method of estimating a force required to separate the powder from an object to which the powder is attached is generally used. As a method for separating powder, a method using centrifugal force, vibration, impact, air pressure, electric field, magnetic field, or the like is known. Among them, the method using centrifugal force is easy to quantify, and is reported in the following papers, for example.

[0003] M. Takeuchi, A. Onose, M. Anzai, R. Kojima
and K.Kawai: "Proc. IS & T 7th Int. Congress Adv. No
n-impact Printing Technology, "1991, vol.1, pp.200-
208 The method used in the above paper is explained. Hereinafter, it is referred to as a centrifugal adhesion measuring method. The measurement cell consisting of the substrate (sample substrate) to which the powder is attached, the substrate (receiving substrate) to which the separated powder is attached, and the member (spacer) installed between the sample substrate and the receiving substrate is placed in the rotor of the centrifugal separator The powder is separated from the sample substrate using centrifugal force generated by the rotation of the rotor and adheres to the receiving substrate. While changing the number of rotations of the rotor from the low-speed rotation to the high-speed rotation, the receiving substrate is exchanged for each rotation, and the above process is repeated. After the powder adheres to the receiving substrate, remove the receiving substrate, observe the powder on the receiving substrate using an optical microscope, capture the image into a computer, perform image processing, and measure the particle size of the powder. I do. The weight of the powder is determined from the particle diameter and the specific gravity of the powder, and the centrifugal force required for separation is calculated from the weight of the powder and the number of revolutions of the rotor to determine the adhesive force of each powder.

[0004] The adhesion of powder varies depending on various factors such as the shape, particle size, material of the powder, the amount of charge when charged, and unevenness of the adhesion surface, material, temperature and humidity. In the field of handling charged powder such as electrophotography, the relationship between the amount of charge of the powder and the adhesive force is particularly important. The adhesive force of the charged powder is the electrostatic adhesive force such as the image force generated by the charge,
It is composed of non-electrostatic adhesion such as van der Waals force and liquid crosslinking force which does not depend on electric charge. In electrophotography, it is important to control the electrostatic adhesion and non-electrostatic adhesion of the toner, and a means for easily measuring these is required.

[0005]

However, in the above-described conventional centrifugal adhesion measuring method, the total adhesion between the charged powder and the surface to which the powder adheres could be measured. It was not possible to measure the electrical and non-electrostatic adhesion separately. In view of the above, a first object of the present invention is to make it possible to measure an electrostatic adhesion and a non-electrostatic adhesion between a charged powder and a surface to which the powder is attached.

In order to achieve the first object, the present invention measures the amount of charge per powder attached to a receiving substrate. The charge amount is completely separated from the substrate, the charge amount is measured, and the charge amount is obtained by dividing by the previously measured number of powders on the receiving substrate. Therefore, in order to accurately measure the amount of charge per powder, it is necessary to confirm that the powder is completely separated from the receiving substrate while measuring the amount of charge.

It is a second object of the present invention to easily confirm the state of separation of the powder from the receiving substrate and to accurately measure the amount of charge per powder.

[0008]

According to the first aspect of the present invention,
In order to solve the above problems, a sample substrate having a sample surface to which powder is attached, a receiving substrate having an attaching surface to which powder separated from the sample substrate is attached, a sample surface of the sample substrate, and the receiving substrate A centrifugal separation step of rotating a measurement cell composed of a spacer provided between the attachment surfaces of the sample substrate and attaching the powder attached to the sample surface of the sample substrate to the attachment surface of the receiving substrate; A centrifugal separation step, a centrifugal separation step for each of a plurality of rotations performed by exchanging the receiving substrate for a plurality of rotation speeds, and a powder number measurement for measuring the particle diameter and the number of powders adhered to the adhering surface of the receiving substrate Step, the weight of the powder is determined from the particle size and specific gravity of the powder, the adhesion calculation step of determining the adhesion of the powder to the sample surface of the sample substrate from the weight of the powder and the rotation speed, Gas is applied to the powder adhering to the adhering surface of the receiving substrate. A powder separating step of separating the powder from the adhering surface of the receiving substrate, a charge measuring step of measuring a charge amount of the receiving substrate, and a step of measuring the amount of the powder adhering to the adhering surface of the receiving substrate. The amount of charge per powder is calculated from the number and the amount of charge, and the electrostatic adhesion and non-electrostatic adhesion are calculated from the relationship between the amount of charge and the adhesion of the powder. Electrical adhesion force calculating step.

According to a second aspect of the present invention, there is provided a powder adhesion measuring method according to the first aspect, wherein a powder adhering step separates the powder adhering to the adhering surface of the receiving substrate. In this case, the powder is separated while observing the place where the powder is separated in an enlarged manner. According to a third aspect of the present invention, there is provided a sample substrate having a sample surface to which powder is attached, a receiving substrate having an attachment surface to which powder separated from the sample substrate is attached, and The measuring cell composed of the sample surface of the substrate and the spacer provided between the attachment surface of the receiving substrate is rotated, and the powder attached to the sample surface of the sample substrate is attached to the attachment surface of the receiving substrate. The centrifugal separation means for attaching, the receiving substrate is exchanged, and the centrifugal separating means for each rotation speed for performing the rotation for a plurality of rotation speeds, and the particle size and the number of powder attached to the attachment surface of the receiving substrate are measured. Means for measuring the number of powders, and determining the weight of the powder from the particle diameter and the specific gravity of the powder, and determining the adhesion of the powder to the sample surface of the sample substrate from the weight of the powder and the number of rotations. Adhesion force calculating means, attached to the attachment surface of the receiving substrate Powder separating means for blowing gas onto the body to separate the powder from the adhering surface of the receiving substrate, charge measuring means for measuring the amount of electric charge of the receiving substrate, and powder adhering to the adhering surface of the receiving substrate The amount of charge per powder is determined from the number of particles and the amount of charge, and the electrostatic adhesion and non-electrostatic adhesion are determined from the relationship between the amount of charge and the adhesion of the powder. Electrical adhesion force calculating means.

According to a fourth aspect of the present invention, there is provided a powder adhesion measuring apparatus according to the third aspect, wherein a place for separating the powder adhered to the adhering surface of the receiving substrate is enlarged. And a separating position enlarging means for observing the object by observation.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to the accompanying drawings. FIGS. 1, 2 and 3 are views showing one embodiment of a measuring cell, a centrifugal separator and a powder charge measuring device of a powder adhesion measuring device according to the present invention.

FIG. 1 is an explanatory view of a measuring cell of a powder adhesion measuring device according to one embodiment. In FIG. 1, reference numeral 1 denotes a measuring cell. The measuring cell 1 has a sample substrate 2 having a sample surface 2a on which powder is adhered, and a receiving substrate 3 having an adhering surface 3a on which powder separated from the sample substrate 2 is adhered. 3 and sample substrate 2
And a spacer 4 provided between the sample surface 2a and the attachment surface 3a of the receiving substrate 3.

FIG. 2 is a partial sectional view of the centrifugal separator of the powder adhesion measuring device according to one embodiment. In FIG. 2, reference numeral 5 denotes a centrifugal separator, and the centrifugal separator 5 includes a rotor 6 for rotating the measurement cell 1 and a holding member 7. The rotor 6 has a hole shape in a cross section perpendicular to its own rotation center axis 9, and has a sample setting section 8 on which the holding member 7 is set. The holder 7 includes a rod 7a, a cell holder 7b provided on the rod 7a to hold the measurement cell 1, a hole 7c for pushing the measurement cell 1 from the cell holder 7b, and a rod 7a as a sample. An installation fixing section 7d for fixing to the installation section 8 is provided. The cell holder 7b is configured such that when the measurement cell 1 is installed, the vertical direction of the measurement cell 1 is perpendicular to the rotation center axis 9 of the rotor. The installation fixing part 7d is shown in FIG.
In the embodiment shown in (1), an elastic material such as rubber is used.

The sample substrate 2, the receiving substrate 3, the spacer 4, and the holding member 7 have strength enough to withstand a large centrifugal force. Since it is necessary to use a light-weight material that is less than the possible weight, an aluminum member was used. FIG. 3 is an explanatory diagram of a powder charge amount measuring device according to one embodiment.

In FIG. 3, a receiving substrate 21 is set on a conductive mounting table 22, and the mounting table 22 is set on an XY stage 24 with an insulating plate 23 interposed therebetween. The XY stage 24 is connected to an XY stage controller 26 through a cable 25, and is controlled by the XY stage controller 26. The mounting table 22 is connected to a charge measuring device 28 through a cable 27, and the charge amount of the receiving substrate 21 is measured by the charge amount measuring device 28.

Nozzle 2 fixed by fixing member 30
9 is connected to a compressor 32 through a tube 31, and by operating the compressor 32, compressed air is blown from the nozzle 29 onto the receiving substrate 21. The powder on the receiving substrate 21 is observed by a CCD camera 33 with a lens fixed by a fixing member 34. C
The CD camera 33 is connected to a camera controller 36 through a cable 35, and the camera controller 36 is connected to a monitor 38 through a cable 37, and an image of the powder on the receiving substrate 21 is displayed on the monitor 38. The CCD camera 33 has a portion that illuminates the observation area, and light is supplied from a light source lamp 40 connected through an optical fiber 39.

The powder separated from the receiving substrate 21 is sucked into the suction device 43 from the suction light 41 through the tube 42. The shield box 44 is grounded through a cable 45. A method for measuring the adhesive force and the charge amount of the charged toner using the apparatus shown in FIGS. 1 to 3 will be described.

First, the toner charged by mixing and agitating the Ricoh toner and the carrier is placed on the sample surface 2a of the sample substrate 2.
Was attached. The charge amount of the toner was 20.5 μC / g as measured by a blow-off method. Next, as shown in FIG. 1, the measurement cell 1 is constituted by using the sample substrate 2, the receiving substrate 3, and the spacer 4. The measuring cell 1 is
Is set on the cell holding portion 7b of the holding member 7 so that the sample substrate 2 is located between the receiving substrate 3 and the rotation center axis 9 of the rotor 6 when the sample is set on the sample setting portion 8 of the rotor 6. The holding member 7 is set so that the vertical direction of the measurement cell 1 is the rotation center axis 9 of the rotor.
Is set on the sample setting section 8 of the rotor 6 so as to be perpendicular to. The centrifugal separator 5 is operated to rotate the rotor 6 at a constant speed. The toner adhered to the sample substrate 2 receives a centrifugal force according to the rotation speed. If the centrifugal force received by the toner is larger than the adhesive force between the toner and the sample surface 2a, the toner separates from the sample surface 2a and The centrifugal force F received by the toner adhering to 3a is the weight m of the toner, the rotational speed f of the rotor,
(Rpm), using the distance r from the central axis 9 of the rotor 6 to the toner adhering surface (sample surface) 2a of the sample substrate 2, is obtained from the following equation (1).

F = m × r × (2πf / 60) ^ 2 (1) The toner weight m is obtained from the following equation (2) using the true specific gravity ρ of the toner and the circle equivalent diameter d. m = (π / 6) × ρ × d ^ 3 (2) From the equations (1) and (2), the centrifugal force F received by the toner is:
It is obtained from the following equation (3).

F = (π ^ 3/5400) × ρ × d ^ 3 × r × f ^ 2 (3) After the centrifugation, the holding member 7 is moved to the sample setting part 8 of the rotor 6.
Then, the measurement cell 1 is taken out from the cell holding portion 7b of the holding member 7. The receiving substrate 3 is replaced, the measuring cell 1 is installed on the holding member 7, the holding member 7 is installed on the rotor 6, and the rotor 6 is rotated at a higher rotation speed than the previous time. The centrifugal force received by the toner becomes larger than the previous time, and the toner having a large adhesive force separates from the sample surface 2a and adheres to the adhesive surface 3a.

By changing the set rotation speed of the centrifugal separator 5 from a low rotation speed to a high rotation speed and performing the same operation,
Depending on the magnitude relationship between the centrifugal force and the adhesive force received at each rotation speed,
The toner on the sample surface 2a moves to the attachment surface 3a. By measuring the particle diameter of the toner adhering to the adhering surface 3a of the receiving substrate 3 at each rotation speed, the adhering force of each toner can be obtained by using the equation (3).

Measurement of the particle diameter and the number of the toner is performed by observing the toner on the adhesion surface 3a with an optical microscope,
The images were taken into a computer through a D camera and performed using image processing software. The movement of the toner observation position on the attachment surface 3a was performed using an XY stage installed on an optical microscope. Receiving substrate 3 for measuring toner particle size
Was set on the mounting table 22 of the powder charge measuring device shown in FIG. While watching the monitor 38,
By operating the suction device 43 and the suction device 43, the compressed air was blown from the nozzle 29 to separate the toner from the attachment surface 3 a of the receiving substrate 3, and the toner was suctioned from the suction port 41. The XY stage 24 was controlled by the XY stage controller 26, and the area to which the compressed air was blown was moved to separate all the toner on the adhesion surface 3a. The charge amount was measured by the charge measuring device 28.
The measured charge was divided by the number of toners measured by the particle size measuring device to determine the charge per toner. If the place where the toner is separated is enlarged and observed and separated, it is possible to know whether each of the toners is separated, and therefore, the amount of charge can be measured more accurately than when the toner is separated by visual observation.

FIG. 4 shows the relationship between the number of revolutions of the rotor 6 and the average value of the adhesion of the toner separated at each number of revolutions. As shown in FIG. 4, as the number of rotations increases, toner having a large adhesive force is separated. FIG. 5 shows the relationship between the rotation speed of the rotor 6 and the amount of charge per toner separated at each rotation speed. As shown in FIG. 5, as the rotation speed increases, toner having a large charge amount is separated.

From FIGS. 4 and 5, the relationship between the charge amount of the toner and the adhesive force is such that the adhesive force increases in proportion to the square of the charge amount, as shown in FIG. It is known that the mirror image force increases in proportion to the square of the charge amount of the powder, and the result in FIG. 6 also corresponds. In the approximate curve shown in FIG. 6, the non-electrostatic adhesive force Fne is obtained from the adhesive force when the charge amount Q is set to 0, and the electrostatic charge is obtained from the following equation (4) using the slope K of the approximate curve. Force Fe is required. Fne and K in FIG.
Is Fne = 23.5 (nN), K = 27.65 (nN /
fC ^ 2).

Fe = K × Q ^ 2 (4) As described above, by measuring the adhesion and the charge of the powder selected by centrifugation, the relationship between the charge and the adhesion can be examined. Electrostatic and non-electrostatic adhesion can be easily measured. The embodiments of the present invention have been described above, but the present invention is not limited to these embodiments.

[0026]

According to the measuring method of the present invention, the particle size of the powder separated from the sample surface of the sample substrate and adhered to the adhering surface of the receiving substrate is measured by the centrifugal separator. The amount of charge per powder can be determined by measuring the adhesion between the powder and the sample surface and measuring the amount of charge in the powder suction container that sucks the powder attached to the adhesion surface of the receiving substrate. Since the relationship between the charge amount and the adhesive force can be obtained, the electrostatic adhesive force and the non-electrostatic adhesive force of the powder can be obtained.

According to the measuring method of the second aspect,
Accurately measure the amount of charge per powder because the position where the powder adhering to the receiving substrate is suctioned can be magnified and observed, so that the powder can be easily separated from the adhering surface. Thus, the electrostatic adhesion and the non-electrostatic adhesion of the powder can be accurately obtained. According to the measuring device of the third aspect of the present invention, the particle size of the powder separated from the sample surface of the sample substrate and adhered to the adhering surface of the receiving substrate is measured by the centrifugal separator, whereby the powder and the sample are measured. The adhesion to the surface can be measured, and the amount of charge per powder can be determined by measuring the amount of charge in the powder suction container that sucks the powder attached to the surface of the receiving substrate. Since the relationship between the amount and the adhesion can be determined, the electrostatic adhesion and the non-electrostatic adhesion of the powder can be determined respectively.

According to the measuring device of the invention described in claim 4,
Accurately measure the amount of charge per powder because the position where the powder adhering to the receiving substrate is suctioned can be magnified and observed, so that the powder can be easily separated from the adhering surface. Thus, the electrostatic adhesion and the non-electrostatic adhesion of the powder can be accurately obtained.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing one embodiment of a measurement cell of a powder adhesion measuring device according to the present invention.

FIG. 2 is a partial cross-sectional side view of a centrifugal separator of the powder adhesion measuring device of one embodiment.

FIG. 3 is a configuration diagram showing a powder charge amount measuring device according to one embodiment.

FIG. 4 is a diagram showing an average value of the adhesive force of the toner separated at each rotational speed with respect to the rotational speed of the rotor measured by the powder adhesive force measuring device in one embodiment.

FIG. 5 is a diagram illustrating a charge amount per toner separated at each rotation speed with respect to a rotation speed of a rotor measured by a powder charge amount measurement device in one embodiment.

FIG. 6 is a graph showing an adhesive force with respect to a charge amount per toner measured by a powder adhesive force measuring device in one example.

[Explanation of symbols]

 Reference Signs List 1 measurement cell 2 sample substrate 2a sample surface 3 receiving substrate 3a attachment surface 4 spacer 5 centrifugal separator 6 rotor 7 holding member 7a rod-shaped portion 7b cell holding portion 7c hole 7d installation fixing portion 8 sample installation portion 9 rotation center shaft 21 receiver Substrate 22 Installation table 23 Insulator 24 XY stage 25, 27, 35, 37, 45 Cable 26 XY stage controller 28 Charge measuring device 29 Nozzle 30, 34 Fixing member 31, 42 Tube 32 Compressor 33 CCD 36 Camera controller 38 Monitor 39 Optical fiber 40 light source lamp 41 suction port 43 suction device 44 shield box

Claims (4)

[Claims] 1. A sample substrate having a sample surface to which powder is adhered, a receiving substrate having an adhesion surface to which powder separated from the sample substrate is adhered, and an adhesion between the sample surface of the sample substrate and the receiving substrate A centrifugal separation step of rotating a measurement cell composed of a spacer provided between the surfaces, and adhering the powder adhered to the sample surface of the sample substrate to the adhering surface of the receiving substrate; The step, by replacing the receiving substrate, a centrifugation step by rotation speed to perform a plurality of rotation speed, a powder number measurement step of measuring the particle size and the number of powder adhered to the adhesion surface of the receiving substrate, An adhesive force calculating step of obtaining the weight of the powder from the particle diameter and the specific gravity of the powder, and obtaining the adhesive force of the powder to the sample surface of the sample substrate from the weight of the powder and the rotation speed; Gas is blown to the powder attached to the attached surface of the substrate By doing so, a powder separation step of separating the powder from the attachment surface of the receiving substrate, a charge measurement step of measuring the amount of charge of the receiving substrate, and the number of powders attached to the attachment surface of the receiving substrate The amount of charge per powder is calculated from the amount of charge, and the electrostatic adhesion and non-electrostatic adhesion are determined from the relationship between the amount of charge and the adhesion of the powder. A method for measuring the adhesion of powder, comprising: an adhesion calculation step; 2. The powder adhesion measuring method according to claim 1, wherein a place where the powder is separated is enlarged in a powder separation step of separating the powder adhering to the adhesion surface of the receiving substrate. A method for measuring the adhesive force of a powder, wherein the powder is separated while observing the powder. 3. A sample substrate having a sample surface to which powder is adhered, a receiving substrate having an adhesion surface to which powder separated from the sample substrate adheres, and an adhesion between the sample surface of the sample substrate and the receiving substrate. A centrifugal separation means for rotating a measuring cell composed of a spacer provided between the surfaces and adhering the powder adhering to the sample surface of the sample substrate to an adhering surface of the receiving substrate; Exchanging a plurality of rotation speeds, a centrifugal unit for each rotation speed for performing the rotation for a plurality of rotation speeds; a powder number measurement unit for measuring the particle size and the number of powders attached to the attachment surface of the receiving substrate; Adhesive force calculating means for obtaining the weight of the powder from the particle diameter and specific gravity of the body, and obtaining the adhesive force of the powder to the sample surface of the sample substrate from the weight of the powder and the number of rotations; A gas is blown onto the powder attached to the surface, A powder separating unit that separates from the adhering surface of the receiving substrate; a charge measuring unit that measures the amount of electric charge of the receiving substrate; Calculating an electrostatic adhesion and a non-electrostatic adhesion from the relationship between the charge of the powder and the adhesion, and calculating an electrostatic adhesion and a non-electrostatic adhesion. A powder adhesion measuring device. 4. A powder adhesion measuring apparatus according to claim 3, further comprising a separation position enlarging means for enlarging and observing a place where the powder adhering to the adhering surface of the receiving substrate is separated. Powder adhesion measuring device.