JPH0511511A - Instrument for measuring electrostatic charge quantity of toner of developing device - Google Patents

Abstract

PURPOSE:To allow the measurement of the electrostatic charge quantity of the toners of a developing device with extremely high accuracy and reliability by measuring the charge quantity of the accumulated toners. CONSTITUTION:A capturing means 40 which is previously subjected to the measurement of its initial weight is connected to a suction slit 41. The toners applied on a developing sleeve 11 limited in its rotating speed by an aging mechanism 20 to the conditions under which the sleeve is actually used with a copying machine, etc., are captured by the capturing means 50 via the suction slit 41. The captured weight is indicated by a difference in the weight of the capturing means 50 before and after the capturing. On the other hand, the charges of the polarity reverse from the polarity of the toners sucked from the developing sleeve 11 are accumulated in a capacitor 61 connected to the developing sleeve 11. The average charge quantity per unit weight of the toner is calculated by the weight of the entire toner captured from the developing sleeve 11 and the accumulated charge quantity of the capacitor 61. The average electrostatic charge quantity per unit area is calculated from the accumulated charge quantity of the capacitor 61 and the total suction area of the outer peripheral surface of the developing sleeve 11.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a developing device charge amount measuring device for measuring the charge amount of toner applied to a developing sleeve of a developing device in an image forming apparatus such as electrophotography and electrostatic recording.

[0002]

2. Description of the Related Art In electrophotographic and electrostatic recording processes, the developing process is an extremely important process that determines the image quality. In this developing step, the toner charge amount of the developer is the most basic parameter and has a great influence on the image quality. Therefore, in developing, designing, and maintaining the apparatus, a measuring apparatus that accurately and easily measures the charge amount of toner is required.

As a method for measuring the charge amount of toner, Japanese Patent Laid-Open Nos. 61-44367 and 61-61064 are available.
Japanese Patent Laid-Open No. 61-61065 and Japanese Patent Laid-Open No. 61-61065, and the Faraday cage method is well known.

The toner charge amount measuring method disclosed in the above publication is as follows.

A voltage is applied to the toner holding medium made of metal to adhere the toner, and the amount of toner (g)
To measure. Next, the voltage is cut off, the toner holding medium is grounded via the capacitor, compressed air is blown to blow off the toner, and the charge (μC / g) of the polarity opposite to the toner generated by the toner holding medium is obtained by calculation.

The suction type Faraday cage method will be described with reference to FIG. 3. A grounded Faraday cage 3 and a collecting net 5 are arranged in a part of the periphery of the developing sleeve 1 to provide a constant area on the outer periphery of the developing sleeve. The toner applied to the toner is sucked by the suction pump 4 and collected in the collecting net 5. The charge amount inside the Faraday cage 3 is measured by an electrometer 7 connected in parallel to the capacitor 6, and the charge amount per unit area (μC / cm ² ) is calculated.

[0007]

In the measuring method disclosed in the above publication, if the area of the toner holding medium is sufficient, the absolute amount becomes large and highly accurate and reliable measurement can be performed.
However, since the toner is blown laterally to the surface of the toner holding medium by the compressed air, when the toner is blown, the toner is frictionally charged with the toner holding medium, and there is a high possibility that unexpected new charging will occur.

Further, in the suction type Faraday cage method, of the toner applied to the developing sleeve, only a certain area of the toner exerted by the powerful air suction device is sucked, so that the absolute amount is small and the measured value is not uniform. Is large and inferior in reliability. In order to increase the absolute amount of the toner to be sucked and increase the measurement accuracy of the toner charge amount, after sucking a certain area from the surface of the developing sleeve 1 whose exposed area is precisely limited, the developing sleeve 1 is manually rotated. It is necessary to repeat the operation of sucking from the surface of the sleeve newly coated with toner.

However, such a measuring procedure cannot be said to be in agreement with the situation in which the developing sleeve 1 rotates at the speed of the actual copying operation and the toner is charged between the surface of the sleeve and the coating blade. .

Further, the attracted toner is likely to come into contact with the inner wall of the introduction portion of the Faraday cage 3 until it is guided to the filter, and is subject to unnecessary frictional electrification, which makes it impossible to accurately measure the electrification amount. There is.

The present invention solves such a problem, and an object of the present invention is to provide a measuring device capable of extremely accurately and reliably measuring the toner charge amount of a developing device. Another object of the present invention is to evaluate the matching property in conformity with the developing system condition of an actual developing device,
Another object of the present invention is to provide a toner charge amount measuring device capable of performing efficient measurement in a short time.

[0012]

According to the charge amount measuring device for a developing device of the present invention as defined in claim 1, the developing device of the image forming apparatus is detachably mounted and the developing sleeve of the developing device is rotated. An aging mechanism provided with a drive motor, a control means provided in the aging mechanism for controlling the rotation speed and rotation time of the drive motor, and a suction slit for sucking the toner applied to the outer peripheral surface of the developing sleeve. A suction mechanism, a collecting means connected to the suction mechanism for collecting toner sucked through the suction slit, a condenser provided between the developing sleeve and the earth ground, and connected in parallel to the condenser. And a charge measuring device having an electrometer, thereby achieving the above object.

Preferably, a developing unit of the image forming apparatus is detachably mounted, and an aging mechanism equipped with a drive motor for rotating a developing sleeve of the developing unit, and a rotation of the drive motor mounted on the aging mechanism. Control means for controlling the speed and rotation time, a suction mechanism having a suction slit for sucking the toner applied to the outer peripheral surface of the developing sleeve,
A reciprocating mechanism that reciprocates the suction slit of the suction mechanism in parallel with the axial direction of the developing sleeve, a collecting unit that is connected to the suction mechanism and collects the toner sucked through the suction slit, and the developing sleeve and the earth ground. And a charge measuring device having a capacitor and an electrometer connected in parallel to the capacitor, and
Thereby, the above object is achieved.

[0014]

In the developing device charge amount measuring device of the present invention, the collecting means whose initial weight is measured in advance is connected to the suction slit.

Then, the toner applied to the developing sleeve whose rotation speed is limited by the aging mechanism to the condition actually used in the image forming apparatus such as a copying machine is sucked through the suction slit and is aforesaid. It is collected by the collecting means. The weight of all the toner applied to the developing sleeve is represented by the difference in weight of the collecting means before and after collecting. On the other hand, in the capacitor connected to the developing sleeve, a charge having a polarity opposite to that of the toner generated when the toner is sucked from the developing sleeve is accumulated. Average charge amount per unit weight of toner (μC
/ G) is calculated from the weight (g) of all the toner collected from the developing sleeve and the amount of accumulated charge (μC) of the capacitor.

The average charge amount per unit area is calculated from the accumulated charge amount (μC) of the capacitor and the total suction area of the outer peripheral surface of the developing sleeve.

[0017]

EXAMPLES The present invention will be described below with reference to examples.

The developing device measured by the toner coating amount measuring device of the present invention is constructed, for example, as shown in FIG. 4 in an actual developing device. This developing device has a photosensitive drum M1 and a developing sleeve 11 that is provided in parallel with the photosensitive drum M1 and carries toner to be transferred to the photosensitive drum M1. The developing sleeve 11 is provided in parallel with the outer peripheral surface thereof and is provided in parallel with the supply roller M2 for transferring and carrying the toner to the developing sleeve 11, and the thickness of the toner carried on the developing sleeve 11 and brought into contact with the rotating developing sleeve 11. And a layer regulating member M3 for making the above uniform. A toner hopper M4 is provided above the supply roller M2, and the toner hopper M4 has a supply port for supplying toner to the developing sleeve 11 and the supply roller M2 at the lower end.

The toner application amount measuring apparatus of the present invention has an aging mechanism 20 to which the developing device 10 can be detachably mounted, as shown in FIG. The aging mechanism 20 includes a drive motor 21 that rotates the developing sleeve 11 of the developing device 10.
Are equipped with. Drive motor 21 and developing sleeve 11
Are connected by a belt 22 and a pulley 12. The drive motor 21 is used for the developing sleeve 1 of the developing device 10.
The drive is controlled by the control unit 30 so that the rotation speed and the rotation time of 1 are set to desired values.

The aging mechanism 20 is connected to the suction mechanism 40. The suction mechanism 40 includes a cylindrical cap 44 having a suction slit 41 at its tip and a suction drive unit 42.
And a cylindrical accommodating portion 43 that is connected to the suction drive portion 42 and accommodates the cap 44. The suction slit 41 is
It is formed of an elongated hole elongated in the axial direction of the developing sleeve, and is arranged very close to the outer peripheral surface of the developing sleeve 11 of the developing device 10.

The collecting means 50 is converged in the accommodating portion 43 of the suction mechanism 40 so that it can be replaced. Collecting means 50
Is formed into a bag shape by a thin plate having fine pores smaller than the toner particles, for example, paper, cloth, or a metal net.
The collecting means 50 is not limited to the above-mentioned thin plate or bag shape.

The collecting means 50 may collect the sucked toner, measure the weight before and after the collection, and calculate the weight of the toner. The collecting means 50 may be, for example, a solution reservoir that stores the liquid that dissolves only the toner by passing the air sucked together with the toner into the liquid.

A charge measuring device 60 is connected between the developing sleeve 11 of the developing device 10 and the earth ground 63. The charge measuring device 60 has a capacitor 61 connected between the developing sleeve 11 and the earth ground 63, and an electrometer 62 is connected to both electrodes of the capacitor 61.
The earth ground 63 may be connected to the aging mechanism 20 and the entire aging mechanism 20 may be grounded.

The charge amount measuring device of the developing device having such a configuration is operated and measured as follows. The developing device 10 to be measured is removed from the image forming apparatus and temporarily installed in the aging mechanism 20 at a predetermined position. A belt 22 is hung on the pulley 12 of the developing device 10 to connect the drive motor 21 and the developing sleeve 11.

The control means 30 sets the rotational speed of the developing sleeve 11 to a desired value. The electric charge of the capacitor 60 is leaked and the electric charge amount is set to 0 (μC). The developing sleeve 1 has a suction slit leaving an optimum gap for sucking the toner applied to the outer circumferential surface of the developing sleeve 11.
The suction mechanism 40 is arranged so as to be close to the outer peripheral surface of 1.
Usually, the optimum gap is formed by temporarily installing the developing device 10 at a prescribed position of the aging mechanism 20. The gap may be finely adjusted after the temporary installation.

When the drive motor 21 is driven in the state set as above, the toner is charged by the pressing of the layer thickness regulating member M4 in the developing device and the rotating action of the developing sleeve 11, and at the same time, the developing sleeve 11 is charged. It is evenly applied to the surrounding area. At the same time, the suction mechanism 40 operates and the suction drive unit 42
The toner applied to the outer peripheral surface of the developing sleeve 11 is sucked together with air from the suction slit 41 by the air suction force. Since the toner is sucked through the collecting means 50, all the sucked toner is collected by the collecting means 50.

Since the suction slit 41 is a thin slit, the suction force of the toner over a predetermined width is uniform and strong, and the toner on the outer peripheral surface of the photosensitive drum 11 is almost completely sucked without being left. The collecting means 50, after driving the drive motor 21 and the suction mechanism 40 for a desired time, stops driving them and is taken out from the accommodation portion 43. Then, the weight of each of the collecting means 50 before and after collecting the toner is strictly measured. The weight G of the collected toner is indicated by the difference between the weight G _{2 of the} collecting means 50 after the toner is collected and the initial weight G ₁ .

A charge having a polarity opposite to that of the attracted and removed toner is accumulated in the capacitor 60, and the accumulated charge amount Q is calculated by the voltage V measured by the electrometer 62 as follows. Q = CV, where C is the capacitance between the sleeve and the ground conductor, and the average charge of the toner (μC
/ G) is calculated from the weight G of the toner collected by the collecting means 50 and the amount of charge Q (μC) accumulated in the capacitor 61.

On the other hand, the total area S of the outer peripheral surface of the developing sleeve 11 sucked by the suction slit 41 is expressed as follows. Total area S (cmm ² ) = rotating speed of developing sleeve m (mm / se
c) × rotation time of developing sleeve n (sec) × width of suction slit 41 l (mm) Therefore, the amount of accumulated charge k of the capacitor per unit area k
_c (μC / cm ² ) is represented by the following formula.

[0030]

[Equation 1]

If toner is applied to the outer peripheral surface of the developing sleeve 11 and sucked by the suction slit 41, the rotation time n of the developing sleeve 11 can be set to an arbitrary time and is collected by the collecting means 50. The absolute weight of the toner can be increased. For example, the rotation time n is 100 times, 1000
If the number is doubled, the toner of 100 times and 1000 times the weight is collected. Therefore, the accumulated charge amount kc (μc / cm ² ) of the capacitor per unit area is represented by a highly accurate numerical value without fluctuation of the measuring device.

The charge amount measuring device of the present invention may be constructed as shown in FIG. In the figure, the suction mechanism 40
Means that the guide 72 connected to the lower portion of the accommodating portion 43 can slide on the rail 71 installed parallel to the axial direction of the reciprocating sleeve 11 in which the suction slit 41 reciprocates parallel to the axial direction of the developing sleeve 11. Is equipped with. The guide 72 is connected to a guide 74 driven by a motor 73 and reciprocates in parallel with the axial direction of the developing sleeve 11. The suction mechanism 40 reciprocates parallel to the axial direction in a state where the tip of the suction slit 41 is close to the outer peripheral surface of the developing sleeve 11 while maintaining a certain minute gap. The suction mechanism 40 forms a spiral band-shaped portion corresponding to the width of the suction slit 41 for the toner applied to the entire outer peripheral surface of the developing sleeve 11 so as to move in the axial direction around the rotating developing sleeve 11. So as to suck. In this manner, the toner present on the outer peripheral surface of the developing sleeve 11 is sucked at a location that does not overlap the previous rotational position of the toner, and thus the toner that has been repeatedly charged is measured. Further, by fixing the suction mechanism 40 and constantly comparing the newly applied toner with the measurement result from the same position of the rotating sleeve, the repetitive charging property of the toner and the toner exchange performance of the developing device 10 are evaluated. , You can get useful data.

[0033]

According to the present invention, the toner charge amount measuring device of the developing device can measure the charge amount of all the toner by sucking the toner applied to the outer peripheral surface of the developing sleeve from a wide area during many rotations. Therefore, the absolute amount of the collected toner can be increased. Therefore, according to this measuring apparatus, accurate and reliable measurement with less measurement error by the measuring apparatus can be efficiently performed in a short time. The toner is completely sucked by the thin suction slit and is not blown in the horizontal direction, so there is no worry of rubbing and charging, and the charge of the opposite polarity generated in the developing sleeve is measured, so secondary charging of toner after suction is ignored. Yes, and thus a value close to true charge is obtained. The suction mechanism is
If it is connected to a reciprocating mechanism that reciprocates parallel to the axial direction of the developing sleeve, it will suck the toner existing on the outer peripheral surface of the developing sleeve at a position that does not overlap with the previous rotation position of the toner, and thus repeatedly charge the toner. The received toner is measured. Also, by fixing the suction mechanism and always comparing the newly applied toner with the measurement result from the same location of the rotating sleeve, it is useful for evaluating the repetitive charging property of the toner and the toner exchange performance of the developing device. Data can be obtained.

[Brief description of drawings]

FIG. 1 is a side sectional view showing a toner charge amount measuring device of a developing device of the present invention.

FIG. 2 is a perspective view showing another embodiment of the charge amount measuring device of the developing device of the present invention.

FIG. 3 is a perspective view showing a toner charge amount measuring device of a conventional developing device.

FIG. 4 is a sectional view of a developing device of a one-component developing system.

[Explanation of symbols]

10 Developer 11 Development sleeve 20 Aging mechanism 21 Drive motor 22 belt 30 control means 40 suction mechanism 41 Suction slit 42 Suction drive unit 43 Housing 50 Collection means 60 charge measuring instrument 61 Capacitor 62 electrometer 63 Earth ground 70 reciprocating mechanism

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Yoshihisa Kuramae             1-22 Tamatsukuri, Chuo-ku, Osaka Mitako             Business (72) Inventor Takeshi Watanabe             1-22 Tamatsukuri, Chuo-ku, Osaka Mitako             Business

Claims (2)

[Claims] 1. An aging mechanism equipped with a drive motor for removably mounting a developing device of an image forming apparatus and rotating a developing sleeve of the developing device; and rotation of the driving motor provided in the aging mechanism. Control means for controlling the speed and rotation time, a suction mechanism having a suction slit for sucking the toner applied to the outer peripheral surface of the developing sleeve, and a toner connected to the suction mechanism to collect the toner sucked through the suction slit. And a charge measuring device having a capacitor and an electrometer connected in parallel to the capacitor, which is provided between the developing sleeve and the ground, and measures the toner charge amount of the developing device. apparatus. 2. An aging mechanism equipped with a developing device of an image forming apparatus detachably and equipped with a drive motor for rotating a developing sleeve of the developing device; and a rotation speed of the driving motor equipped with the aging mechanism. Control means for controlling the rotation time, a suction mechanism having a suction slit for sucking the toner applied to the outer peripheral surface of the developing sleeve, and a reciprocating movement of the suction slit of the suction mechanism in parallel to the axial direction of the developing sleeve. A reciprocating mechanism, a collecting means connected to the suction mechanism for collecting the toner sucked through the suction slit, a condenser provided between the developing sleeve and the earth ground, and connected in parallel to the condenser. A charge measuring device having an electrometer, and a toner charge measuring device for a developing device, comprising: