JPS6161064A - Measuring method of charge amount of toner - Google Patents

Abstract

PURPOSE:To measure the charge amount of toner accurately and easily by applying a voltage to a toner holder and attracting the toner, and connecting a capacitor and a voltmeter after the applied voltage is ceased and removing the toner. CONSTITUTION:The toner holder 11 is placed in opposition to a developing roller 9. This holder 11 is connected to a high-voltage power source 10 and applied with a voltage which differs in polarity from the charge of the toner 3. Then when the roller 9 is rotated, the toner 3 is attracted by the holder 11. At this time, no carrier 4 is attracted and only the toner 3 separates from the carrier 3. Then, the holder 11 which attracts the toner 3 is disconnected from the power source 10 and connected to the circuit consisting of the capacitor 5 and voltmeter 6 connected in parallel, and then the holder 11 has a charge which has the same polarity with and the same level with the toner and it is neutralized. Then, high pressure gas 8 is blown as shown by an arrow A to blow the toner away from the holder 11. Then, the charge moves to the capacitor 5 and a measurement is taken by the voltmeter 6 to obtain the charge amount of the toner.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for measuring the amount of charge of toner used in electrophotography or electrostatic recording devices.

2. Description of the Related Art In the process of electrophotography and electrostatic recording, there is a development step in which a developer consisting of toner and carrier is used to adhere toner to the charge image formed on a recording medium in order to visualize the charge image. This developing step is an extremely important step that determines image quality. In this developing process, the amount of charge of the toner in the developer is the most fundamental parameter that has a large effect on image quality. For this reason, it is important to accurately determine the amount of toner charge in the development, design, and maintenance of the device.
A measurement method is needed to measure j.

[Conventional technology]

The conventional method for measuring the amount of charge on toner is to separate toner and carrier, which are bound together by electrostatic attraction in a developer, through a developing process. That is, as shown in FIG. 3+a+, the surface of the dielectric film l which has been masked B leaving a latent image pattern is charged by the corona charger 2 in the unmasked portion to form a latent image.

Next, as shown in FIG. 3(1), toner 3 is attached to the latent image in a developing step and separated from carrier 4.

Next, as shown in FIG. 3, the dielectric film 1 holding the toner 3 is brought into close contact with the electrode 7 connected to the parallel-connected capacitor 5 and voltmeter 6, and the high-pressure gas 8 is introduced as shown in the arrow A. to blow away toner 3. This connects the capacitor 5 to the electrode 7 (capacitance, C
) transfers the same amount of charge as the blown toner and charges it. Both ends of the capacitor 5 are measured with a voltmeter 6, and the amount of charge Q=CXV is calculated from the measured voltage value (V) to measure the amount of charge.

[Problem that the invention seeks to solve]

The above method involves a complicated process of removing static electricity from the surface of the dielectric material in order to form a latent image on the dielectric material, masking it by leaving a latent image pattern, and charging it, and it is difficult to keep the potential of the latent image constant. There are problems such as difficulty and lack of reproducibility of the measurement system.

[Means for solving problems]

The present invention solves the above-mentioned problems and provides a measuring method for accurately and easily measuring the amount of charge of toner. The measuring method includes applying a voltage to a toner holding body formed of a conductor to attract the toner,
After the applied voltage is cut off, a capacitor and a voltmeter are connected between the toner holder and the ground, the adsorbed toner is removed, and the capacitor is charged in accordance with the charge of the removed toner. Measuring the voltage with the voltmeter,
This is done by a toner charge amount measuring method in which the toner charge ViII is measured from the measured value.

[Effect]

The above toner charge measurement method uses a toner holder made of a conductor, applies a high voltage of opposite polarity to the toner to be measured to the toner holder, and converts the toner holder into a developer consisting of toner and carrier. Bring it closer. As a result, only the toner is electrostatically attracted and uniformly attracted to one surface of the toner holder. After connecting a capacitor and a voltmeter connected in parallel between the toner holder and ground, the adsorbed toner is removed from the toner holder. This removal transfers an amount of charge equal to the removed toner to the capacitor, charging it. This charging voltage is measured with a voltmeter to calculate the amount of charge on the toner.

In this way, a toner holder made of a conductor is used as a medium for adsorbing toner, and a voltage of the opposite polarity to that of the toner is directly applied to the toner holder to attract only the toner to the toner adsorption surface of the toner holder. Accordingly, the conventional latent image forming step is omitted, and the potential of the attraction surface of the toner holder is kept constant.

〔Example〕

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

Fig. 1 (ia), (bl, Tel) are schematic diagrams for explaining the steps of an embodiment of the present invention.
As shown in al, a toner holder 11 made of a conductor is placed opposite the developing roller 9. This toner holding body 11
is connected to a high-voltage power supply 10, and a voltage having a polarity opposite to that of the charge on the toner 3 is applied. When the developing roller 9 is rotated,
The toner 3 in the developer is attracted to the toner holder 1 by electrostatic attraction.
Adsorbs to 1. At this time, like the development during image recording, the carrier 4 is not attracted and only the toner 3 is separated from the carrier 4.

Next, the toner holder 11 that has absorbed the toner 3 is disconnected from the high-voltage power supply 10 and connected to a circuit consisting of a capacitor 5 and a voltmeter 6 connected in parallel, as shown in FIG. Charges having the opposite polarity and the same size as the toner exist in the body 11, and are electrically neutralized.

Next, as shown in FIG. 1 (C1), by blowing high-pressure gas 8 in the direction of arrow A, the toner is blown off and removed from the toner holding body 11.
The electric charge present in the capacitor 5 is transferred to the capacitor 5 and charged. Measure the voltage (■) across the capacitor 6 with the voltmeter 6. The amount of charge Q of the toner removed from the capacitance C of the capacitor 5 and the voltage (2) is obtained by Q-C x (2). Also, the mass M of the removed toner can be obtained from the difference in the weight of the toner holding body 11 to which the toner is adsorbed before and after the toner is removed, and the amount of charge per unit mass of toner, that is, the specific gravity of the toner? iiq/m is Q
/M.

Figure 1 fdl shows the measurement results of toner specific charge according to this example.
Shown below. In addition, as the above measurement conditions, using developer A,
The voltage applied to the toner holder is -800V and the developer ear height is 0.
5mm, development distance ji11. oxm.

FIG. 2 shows another embodiment of the invention. This embodiment differs only in the step of removing the toner adsorbed to the toner holder described in FIG. 1 TC) of the previous embodiment. Therefore, this process will be explained.

That is, as shown in FIG.
It is connected to a circuit consisting of.

Here, by performing suction with the suction nozzle 12 approaching the toner holder 11, the toner 3 is removed from the toner holder 11.
It is something that releases and inhales. In this embodiment, the toner 3 that has separated from the toner holder 11 does not adhere to the charge amount measuring circuit system again, thereby preventing erroneous measurements, and since no high-pressure gas is required, the apparatus can be downsized.

In the above-described embodiment, a DC voltage is applied to the toner holder to attract the toner, but it is also possible to apply a voltage containing an AC component. Further, although a two-component developer was used in the above embodiment, the l-ner charge amount can be measured using the same procedure for a one-component developer.

〔Effect of the invention〕

As explained above, according to the present invention, a potential of opposite polarity to the charge of the toner is applied to the toner holding body formed of a conductor,
By separating only the toner from the developer and adsorbing it,
The conventional process of forming a latent image using corona charging is omitted, the potential of the toner adsorption surface remains constant, and the amount of toner charge can be easily measured with high accuracy.

[Brief explanation of the drawing]

FIG. 1 (δ1.
FIG. 1 is a schematic diagram for explaining a method for measuring the amount of toner charge in Norai. In the figure, 1 is a dielectric film, 2 is a corona charger,
3 is a toner, 4 is a carrier, 5 is a capacitor, 6 is a voltmeter, 7 is an electrode, 8 is a high pressure gas, 9 is a developing roller, 10 is a high voltage power source, 11 is a toner holder, and 12 is a suction nozzle. ing. No. 11!1 (Q) Fig. 1 U (b3 Unexamined Japanese Patent Publication No. 61-61064 (4) Fig. 112 “-Gl??l,/’“

Claims (1)

[Claims] A method for measuring the amount of charge of a toner used in an electrophotographic or electrostatic recording device, the method comprising: applying a voltage to a toner holder made of a conductor to attract the toner; and after turning off the applied voltage. , a capacitor and a voltmeter are connected between the toner holder and the ground, and the adsorbed toner is removed, and a charging voltage charged to the capacitor corresponding to the charge of the removed toner is measured with the voltmeter. A toner charge amount measuring method, characterized in that the amount of charge of the toner is measured from the measured value.