JPH03130672A - Measuring apparatus for charge quantity distribution of toner - Google Patents

Abstract

PURPOSE:To accurately perform measurement by controlling a measuring so that the optical density of the toner image formed on a filter enters a specific range. CONSTITUTION:A filter 10 having a toner image 14 formed thereon is placed on a moving stage 23 and the moving quantity of the moving stage 23 is inputted to a computer 25 by a controller 24. A density measuring part 26 measuring the optical density of toner image 14 measures the quantity of the reflected light from the toner image 14 irradiated with a definite quantity of the light from a light emitting part 27 in its light detection part 28. The computer 25 calculates the optical density of the toner image from the quantity of light of the light emitting part 27 and the quan tity of the light detected by the light detection part 28 and the optical density of the toner image is controlled by a measuring time control means so as to become 0.2 - 1.2. When the optical density is out of this range, the indication of re-measurement is issued by an optical density judging means 30 and, when the optical density is within said range, the moving quantity data of the moving stage 23 and the optical density data of the toner image 14 are obtained to calculate the charge quantity distribution of toner by calculation processing.

Description

[Detailed Description of the Invention] [Summary] An object of the present invention is to enable accurate toner charge amount distribution measurement with respect to a toner charge amount distribution measuring device that measures the charge amount distribution of toner used in electrophotographic devices, etc. In a toner charge amount distribution measuring device that measures the charge amount distribution of toner particles, a measurement time that manages the measurement time so that the optical density of the toner image formed on the toner collection member is 0.2 to 1.2. The structure shall include a management means. Further, the above structure may be further provided with an optical density determining means for determining whether the optical density of the toner image formed on the toner collecting member is between 0.2 and 1.2.

[Industrial application field]

The present invention relates to a charge amount distribution measuring device for measuring the charge amount distribution of toner used in electrophotographic devices and the like.

In the electrophotographic method used in laser printers, etc.
The amount of charge of toner, which is a developer that forms images, is one of the most important factors that influences development characteristics and transfer characteristics.

Therefore, measurement methods have been studied for a long time. However, the conventional blow-off method is a method that measures the average charge amount of a certain amount of toner, and it confirms the presence of toner with a small charge amount that causes fogging and other deterioration of image quality, and toner that is charged with the opposite polarity to the required polarity. It was difficult to do so. In view of this problem, in recent years, a toner charge amount distribution measuring method has been studied, which measures the charge amount of each toner and captures the charge amount of the toner as a distribution.

[Conventional technology]

FIG. 8 shows an outline of the structure of a conventional toner charge amount distribution measuring device, and FIG. 9 shows a block diagram of a data processing system of the device.

In FIG. 8, reference numeral 1 denotes a sample chamber containing toner particles to be measured, where the toner particles are individually separated by nitrogen blowing. Reference numeral 2 denotes a toner introduction path through which toner particles (sample) are introduced into the measuring section. The sample chamber 1 and the toner introduction path 2 constitute a third means. 3 is a cylindrical housing that constitutes the measuring device. 4 is an air suction device that generates an air flow within the housing 3.

After the air flow inside the housing 3 enters, the air flows through a nylon mesh screen 5. By passing through the linear airflow generator 6, the airflow becomes an airflow with a substantially flat flow velocity distribution and a uniform airflow direction, and flows downward in the figure. Air suction device 4. Mesh screen 5. The straight airflow generator 6 constitutes the first means. 7 is a pair of side wall electrodes for deflection so that an electric field is formed in the housing 3 in a direction perpendicular to the direction of the air flow.
Different voltages are provided by a power source 8. The side wall electrode 7 and the power source 8 constitute second means. Toner particles 9 are carried by the air flow and deflected by the electric field formed by the electrode 7. Reference numeral 10 denotes a filter (fourth means serving as a toner collecting member) that collects the deflected toner particles 9. 11 is a support member for the filter 10.

The operation of this device is as follows.

The toner particles 9 are separated individually in the sample chamber 1, guided through the toner introduction channel 2 into the interior of the housing 3, and carried downward by the air flow. The transported toner particles 9 are
The electric field formed by the electrode 7 causes the toner introduction path 2 to
The filter 10 for detecting toner adhesion is deflected in a direction perpendicular to the central axis (in the direction of the electric field, perpendicular to the direction of the air flow).
Adhere to the top. This displacement in the deflection direction is a function of the size and charge of the toner particles. Literature (R,B.

Lewis et al., “A CHARGE 5PECTRO
GRAPHFORXEROG-RAPHICTONER
”, Journal of the Electrophotography Society Vol. 22 No. 1 P, 85 (19
According to 83)), if the electric field is E, the air flow velocity is Va, the toner displacement is X, and the toner particle diameter is d, the distance from the tip of the toner introduction path 2 to the toner collection filter 10 is The amount of charge held can be obtained by the following formula.

However, η: Air viscosity The amount of displacement X and the amount of adhesion of the toner particles 9 collected on the filter 10 are measured by the data processing system shown in FIG. 9, and the toner charge amount distribution is determined. That's right.

The filter 10 that has collected the toner particles is taken out from the apparatus shown in FIG. 8 and set on a moving table 12. 13 is the optical density OD of the toner image 14 on the set filter 10
The density measurement section is comprised of a light emitting section 15 that irradiates the toner image 14 with a constant amount of light, and a light receiving section 16 that receives reflected light from the toner image 14 . Optical density OD is defined by the following equation.

OD=logto (amount of reflected light/amount of incident light) There is a relationship shown in FIG. 10 between the amount of toner adhesion per unit area and the optical density OD. Therefore, the amount of toner adhesion can be determined by measuring the optical density.

The displacement amount X can be determined from the moving distance of the movable table 12 on which the filter 10 is set.

Reference numeral 17 denotes a computer, which calculates the toner charge amount distribution by calculation processing from the toner adhesion amount and displacement amount obtained by the density measuring section 13 as described above.

[Problem to be solved by the invention]

When measuring the toner charge amount distribution using a conventional measuring device having the above-mentioned configuration 2 effect, as shown in FIG. If the optical density OD of the toner image obtained on the filter 10 is too large, an accurate toner adhesion amount cannot be obtained and the charge amount distribution will also be inaccurate.

Furthermore, if the amount of toner adhering to the filter 10 is small (the optical density of the toner image 14 is small), the difference from the optical density of the portion to which toner does not adhere is small (as a result, an accurate charge amount distribution cannot be obtained).

An object of the present invention is to provide a toner charge amount distribution measuring device that enables accurate toner charge amount distribution measurement.

[Means to solve the problem]

In order to solve the above-mentioned embodiment, in the present invention, in the toner charge amount distribution measuring device, the measurement time is set so that the optical density of the toner image formed on the toner collecting member is 0.2 to 1.2. The configuration includes a measurement time management means for managing the measurement time.

Furthermore, the above structure may be further provided with an optical density determining means for determining whether the optical density of the toner image formed on the toner collecting member is between 0.2 and 1.2.

[For production]

As is clear from FIG. 10, which shows the relationship between toner adhesion amount and optical density OD, when the optical density becomes 1.2 or more, it becomes saturated regardless of the toner particle size. That is, when the optical density is 1.2 or less, the toner adhesion amount and the optical density are in a proportional relationship, so the toner adhesion amount can be determined from the optical density.

Further, FIG. 6 shows the relationship between the peak optical density of the toner image on the toner collecting member and the variation in the toner charge amount distribution obtained as a result of calculation processing (the variation in the charge amount distribution is determined when the optical density is 0. 68), the variation in the charge amount distribution is significantly large in a small region where the peak optical density is 0.2 or less. This is because, in addition to variations in the charge amount distribution itself, the peak optical density is small, resulting in a large error in the toner adhesion amount.From this figure, it can be seen that when the peak optical density is 0.2 or more, the charge amount is small. It can be seen that the dispersion of the distribution becomes almost constant.

From the consideration of the above experimental data, in order to measure the toner charge amount distribution stably and accurately, the peak optical density of the toner image on the toner collecting member must be in the range of 0.2 or more and 1.2 or less. There needs to be.

By the way, in a device that uses an air flow and an electric field to form a toner image on a collection filter (toner collection member) according to the amount of toner charge, as shown in Fig. 7, which shows the relationship between measurement time and optical density, Furthermore, as the measurement time becomes longer, more toner adheres to the collection filter. Therefore, in the present invention, a measurement time management means is provided to manage the measurement time so that the optical density of the toner image is 0.2 to 1.2.

This makes it possible to accurately measure the toner charge amount distribution.

Further, in the present invention, an optical density determining means is provided for determining whether the peak optical density of the toner image on the toner collecting member is in the range of 0.2 to 1.2.

Therefore, based on this judgment result, the peak optical density is 0.2~
If the value is outside the range of 1.2, the measurement is stopped, thereby preventing unauthorized measurement.

〔Example〕

The present invention will now be described in detail with reference to FIGS. 1-5.

A first embodiment is shown in FIGS. 1 to 3.

FIG. 1 is a schematic structural diagram of the toner charge amount distribution measuring device of this example, and FIG. 2 is a block diagram showing the data processing system of the device. In the figure, 21 is a device control section, 22 is a device control section This is a measurement time management means provided within the system. Note that the same reference numerals are used for members that are common to the conventional one.

First, a supplementary explanation of some of the members common to the conventional one is as follows.

The housing 3 is made of acrylic and has a diameter of 160 mm. The mesh screen 5 is a nylon net and has the effect of equalizing the speed of air flow.

The linear airflow generator 6 is a lattice-like structure made by bundling a large number of nylon tubes, and plays the role of aligning the direction of airflow. The filter (toner collecting member) 10 is made of glass fiber. The support member 11 holds the filter 10 so as not to be deformed by the pressure of the air flow.

The device control section 21 performs on/off control of the main parts of the device, specifically, the air suction device 4. A power source for creating an electric field within the housing 3 8. and controls on/off of the nitrogen blow that separates the toner in the sample chamber 1.

The measurement time management means 22 plays a role of setting the optical density of the toner image formed on the filter 10 in the range of 0.2 to 1.2 by setting the measurement time to a constant value.

In the case of normal toner, a measurement time of 2 to 5 minutes or more is required to obtain an optical density of 0.2 or more.

During the measurement, an air flow is generated inside the housing 3 by the air suction device 4. Air flow is mesh screen5. The straight airflow generator 6 arranges the airflow at a constant speed and in a constant direction. The flow velocity is 0.5 m/s. On the other hand, sample chamber 1
The individually separated toner particles 9 are introduced into the housing 3 through the toner introduction path 2 and are carried downward by the air flow. The toner particles 9 are deflected by an electric field generated by the pair of electrodes 7 according to the amount of charge of the toner particles themselves, and adhere to the filter 10 . The above operations are performed until the time set by the measurement time management means 22, and the measurement is completed. The pattern of the toner image deposited on the filter 10 in this manner is determined by processing by the data processing system shown in FIG. The details are as follows.

In FIG. 2, 23 is a moving stage, and the toner image 14 is
The filter 10 on which the filter 10 is formed is placed on the moving stage 23. A controller 24 for the moving stage 23 inputs the amount of movement of the moving stage 23 into a computer (seventh means) 25 and receives movement instructions from the computer 25. 26 is a density measuring section (sixth means) that measures the optical density of the toner image 14 on the filter 10. The density measurement unit 26 includes a light emitting unit 27 that irradiates the toner image 14 with a constant amount of light, and a light receiving unit 28 that measures the amount of light reflected from the toner image 14.
It consists of. An LED was used for the light emitting section 27, and a phototransistor whose voltage level changed depending on the amount of light received was used for the light receiving section 28. 29 is an A/D converter that converts the analog signal from the light receiving section 28 into a digital signal and inputs it to the computer 25. computer 2
In step 5, the optical density OD is calculated from the amount of light from the light emitting section 27 and the amount of light received by the light receiving section 28, which have been input in advance. Then, if the optical density is outside the range of 0.2 to 1.2 by the optical density determination means 30 provided in the computer 25, re-measurement is necessary because accurate measurement data cannot be obtained as described above. Instruct the measurer to do so. If the optical density is within the range of 0.2 to 1.2 as a result of the determination, the computer 25 obtains the movement amount information of the moving stage 23 and the optical density information of the toner image 14, and calculates the toner charge by calculation processing. Find the quantity distribution. 31 is an output device that outputs the measurement results of the toner charge amount distribution.

The measurement results obtained by this measuring device are as illustrated in FIG. In FIG. 3, the horizontal axis represents the toner charge amount q/d normalized by the toner particle size d, and the vertical axis represents the toner 31M.
are taken respectively. In this embodiment, the toner amount M is normalized by the peak value. That is, let the minimum value be O,
The maximum value is displayed as 1. By normalizing the toner adhesion amount in this way, the computer 25
Since the calculation process within can be handled using optical density, the calculation process becomes faster. In FIG. 3(a), the optical density at the peak portion is 0.
12, and Figure 3(b) is the case of 0.36, and Figure 3(b) is the case of 0.36.
Figure (C) shows the case of 0.68. In the case of FIG. 3(a), the obtained data do not form a charge amount distribution.

This is because the measurement accuracy decreased due to the small amount of toner adhesion and the low optical density. In this case, in this embodiment, since accurate measurement data cannot be obtained in the optical density determining means 30, an instruction is issued to the measurer to perform the measurement again. On the other hand, in the cases of FIG. 3(b) and FIG. 3(c), where the optical density is 0.2 or more, the distributions are almost the same even though the optical densities are greatly different. Furthermore, if the optical density is 1.2 or more, based on the relationship between toner adhesion amount and optical density shown in Figure 10, an area where the optical density is saturated will be used, and an accurate charge amount distribution will not be obtained. Of course not.

According to this embodiment, accurate measurement of the toner charge amount distribution is possible by providing a measurement time management means for managing the measurement time so that the optical density of the toner image on the filter is 0.2 to 1.2. It became. Furthermore, by providing an optical density determination means for determining whether the optical density of the toner image on the filter is within the range of 0.2 to 1.2, more accurate toner charge amount distribution measurement is possible. .

A second embodiment is shown in FIGS. 4 and 5.

FIG. 4 is a schematic explanatory diagram of the structure of the toner charge amount distribution measuring device of this example. In this device, an air flow 42 is introduced into the measurement container 41.
, and the toner particles 44 to be measured are ejected from the toner introduction nozzle 43 provided on the side surface of the measurement container 41 . The toner particles 44 conveyed by the air flow 42 pass through the electrodes 45.4 depending on the amount of charge on the toner particles 44 along the way.
It is deflected by the electric field 46 formed by 5 and attached to the electrode 45.

FIG. 5 is a schematic structural diagram of a reading device for reading a toner image formed by adhesion of toner particles 44 as described above. When measuring a toner image, the electrode 45 is
The toner image 47 formed thereon is collected using an adhesive tape 48, and the adhesive tape 48 is placed on a moving stage 49. At this time, the adhesive tape 48 and the moving stage 49 are made transparent. In the density measuring section (sixth means) 50, a light emitting section 51 is arranged on the side of the toner image 47, and a light receiving section 52 is arranged on the back side of the toner image 47, and the transmitted optical density of the toner image 47 is measured. Thereafter, the toner charge amount distribution can be obtained through the same processing as in the previous example.

In the case of this example as well, the same effects as in the previous example can be obtained by providing the same measurement time management means and optical density judgment means as in the previous example.

〔Effect of the invention〕

As described above, according to the present invention, the measurement time management means is provided, and by this, the optical density of the collected toner image is defined in the range of 0.2 to 1.2, so that accurate toner It became possible to measure the charge amount distribution. Furthermore, by providing an optical density determination means for determining whether the optical density of the collected toner image is within the range of 0.2 to 1.2, more accurate toner charge amount distribution measurement becomes possible. Ta.

[Brief explanation of the drawing]

FIG. 1 is a schematic structural diagram of a toner charge amount distribution measuring device according to the first embodiment of the present invention, FIG. 2 is a block diagram showing a data processing system, and FIG.
a), (b), and (C) are graphs showing the toner charge amount distribution measurement results; FIG. Figure 5 is a schematic explanatory diagram of the structure of the toner image reading device, Figure 6.
The figure is a graph showing the relationship between optical density and charge amount distribution variation, Figure 7 is a graph showing the relationship between measurement time and optical density, and Figure 8 is a graph showing the relationship between measurement time and optical density.
The figure is an explanatory diagram of the structure of a conventional toner charge amount distribution measuring device. Figure 9 is a block diagram showing a conventional data processing system. Figure 10 is a block diagram showing a conventional data processing system.
The figure is a graph showing the relationship between toner adhesion amount and optical density. In the figure, 3.41 is a measurement container, 9.44 is a toner particle, 14.47 is a toner image, 22 is a measurement time management means, and 30 is an optical density. It is a means of judgment.

Claims (1)

[Claims] 1. In the toner charge amount distribution measuring device, the measurement time is managed so that the optical density of the toner image (14) formed on the toner collecting member is 0.2 to 1.2. A toner charge amount distribution measuring device characterized in that a measurement time management means (22) is provided. 2. Toner charge amount distribution equipped with a measurement time management means (22) for managing measurement time so that the optical density of the toner image (14) formed on the toner collecting member is 0.2 to 1.2. The measuring device further includes an optical density determining means (30) for determining whether the optical density of the toner image (14) formed on the toner collecting member is between 0.2 and 1.2. Characteristic toner charge amount distribution measuring device.