JP3487464B2 - Blow-off device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a blow-off device used for measuring the toner concentration of a two-component developer, and the average charge amount and charge amount distribution of the toner.

[0002]

2. Description of the Related Art The following methods have been conventionally known as methods for measuring the toner concentration of a two-component developer, the average charge amount of toner, the distribution of charge amount of toner, and the like. Faraday cage method: This is the most well-known and simple measurement method using a Faraday cage, and is mainly used for measuring the charge amount of a charged toner of a one-component developer. Blow-off method: A simple and highly accurate measurement method, which is a standard measurement method for the amount of triboelectric charge between powders of different sizes, such as toner and carrier, depending on the device configuration and measurement conditions. It is roughly divided into three. a) Jet type cage blow-off. b) Low flow cage blow-off. c) Magnet blow-off. Development separation method: A method of measuring the charge amount of the developed toner. Toner layer surface potential measurement method: This is a method of obtaining a rough toner charge amount from the surface potential of the developed toner layer. Stationary air flow method (Millican method): This is the most general measurement method for obtaining the amount of charge of individual charged particles by using an electric field and gravity as external forces. Layered air flow method: A measurement method using an air flow and an electric field that exerts a large acting force on toner, and there are the following two types. a) Electric field direction collection type. A type that has a toner collecting member in the direction of the electric field. b) Air flow direction collection type. A type that has a toner collection member in the direction of air flow movement. Simple oscillatory air flow method: Appropriate electric field is applied to charged particles that move downward while oscillating following air vibration caused by sound waves,
This is a measurement method in which the particle diameter and the particle charge amount are simultaneously obtained by measuring the phase delay and the deflection amount of the particles by the laser Doppler method.

Incidentally, these measuring methods are described in detail in the following documents (1) to (3). (1) Kimura, "Development Measuring Method (2)", The Electrophotographic Society of Japan No. 30
Volume 2 (1991). (2) Nakajima et al., "New toner charge measurement method", The Electrophotographic Society of Japan, Vol. 18, No. 3 (1980). (3) Tabata, "Toner particles q / m-
Distribution Measuring Equipment ”, Japan Hardcopy '90 Proceedings, EP-1, P.
1.

[0004]

Next, the advantages / disadvantages of the above-mentioned conventional measuring methods will be described. Faraday Cage Method: Advantages: Easy. Disadvantages: It is difficult to put the toner in the cage, and it is not used for measuring the toner concentration and charge amount of a two-component developer.
It is used to measure the charge amount of one-component toner and the developed toner.

Blow-off method: a) Jet cage blow-off. Advantages: The average amount of charge can be easily measured. Toner density can be measured accurately. Disadvantages: Depending on the developer, frictional electrification may occur due to contact with the mesh or casing during measurement, and a larger (or smaller) result may be obtained. It is possible to obtain data on the charge amount distribution by changing the blow pressure and repeating blow-off, but the reproducibility is poor. b) Low flow cage blow-off. Advantages: The average amount of charge can be easily measured (however, in the case of large particle size iron carriers). Can easily measure the charge distribution
(However, in case of large particle size iron carrier). Disadvantages: To separate toner with a particle size of 5 μm and a specific charge of 30 μC / g from the carrier, a wind speed of 10 m / sec is required, but it is currently lightweight (ferrite of 100 μm or less).
A carrier is mainly used, and such a lightweight carrier floats at the above-mentioned wind speed, and the developer is partially disturbed, so that an accurate charge amount distribution cannot be measured. Further, at a low flow velocity, the toner cannot be completely blown off from the developer. Therefore, an accurate value of toner density cannot be obtained. c) Magnet blow-off. Advantages: The average amount of charge can be easily measured (however, in the case of large particle size iron carriers). Disadvantages: At present, the mainstream is to use a ferrite carrier whose magnetization is smaller than that of iron (ferrite 60 Am ² / kg, while iron has a saturation magnetization of 190 Am ² / kg). Some of them blow off with an air jet, and it is impossible to measure the accurate toner concentration and toner specific charge.

Development Separation Method: Advantage: It is possible to measure a toner having a carrier diameter close to that of the toner. Therefore, it is possible to measure even small particle size ferrite carriers. Disadvantage: The toner charge amount changes during the developing process, and an accurate charge amount cannot be obtained. Since it is difficult to develop all the toner in the developer, it is impossible to accurately measure the toner density.

Toner layer surface potential measurement method: Advantages: It is possible to measure toner particles having a carrier diameter close to that of the toner. Therefore, it is possible to measure even small particle size ferrite carriers. Disadvantage: The toner charge amount changes during the developing process, and an accurate charge amount cannot be obtained. Since it is difficult to develop all the toner in the developer, it is impossible to accurately measure the toner density.

Static air flow method (Millican method): Advantages: The particle size and specific charge of each toner can be measured. Disadvantage: It is difficult to separately introduce the toner into the flask. Measurement of toner density is virtually impossible. It takes an enormous amount of time to measure (it is virtually impossible to measure the distribution of charge amount).

Laminar air flow method: a) Electric field direction collection type. Advantages: Toner particle size and specific charge amount can be measured. An image analyzer after collection can be used. Disadvantage: It is difficult to separately introduce the toner into the measurement parallel plate electrode. Measurement of toner density is virtually impossible. There is a limit to the sampling amount (count number). It takes time to measure. b) Air flow direction collection type. Advantages: Toner particle size and specific charge amount can be measured. Disadvantage: It is difficult to separate and introduce the toner from the developer into the apparatus. Measurement of toner density is virtually impossible. There is a limit to the sampling amount (count number). It takes time to measure.

Single-oscillation air flow method: Advantages: The toner particle size and the specific charge amount can be measured. There is no limit to the sampling amount (count number). Disadvantage: It is difficult to separate and introduce the toner from the developer into the apparatus. Measurement of toner density is virtually impossible. It takes time to measure.

As described above, each of the above-mentioned measuring methods has advantages and disadvantages, and there is no measuring method satisfying all requirements. Therefore, at present, they are used in a form complementary to each other by taking advantage of each measurement method.

The present invention has been made in view of the above circumstances, and an object of the present invention is to use the blow-off method among the above-mentioned measuring methods, in particular, to determine the toner concentration of a two-component developer and the average charge amount of the toner, and An object of the present invention is to provide a device that can easily obtain the charge amount distribution. Further, regarding the toner charge amount distribution, there is a provision of a measuring device that prioritizes simplicity even if the accuracy is somewhat sacrificed (simpleness of the device itself = not only cost but also shortening each measurement time). .

[0013]

In order to achieve the above object, the blow-off device according to the first aspect is such that a conductive mesh is provided above and below a conductive cylinder, and the conductive cylinder and the conductive mesh are electrically connected. a blow-off cell internal conductive tube and the conductive mesh formed into a closed space except conducting the opening of the mesh to each other in a state where the conductive mesh <br/> Interview of the blow-off cell is substantially horizontal in and means for supporting the electrically insulated state from the other, and, possess means for sucking air from below the blow-off cells, and means for blowing air from above the blow-off cells, and, the Blow air
As the means for applying, air is blown to a part of the above conductive mesh.
With a nozzle that sticks, and a nozzle that blows the air
Relative to the conductive mesh while maintaining a distance from each other
And blow air over the conductive mesh.
It is characterized by being able to and.

A blow-off device according to a second aspect of the present invention is the blow-off device according to the first aspect, characterized in that air suction from below is started and air blowing from above is started after a lapse of a predetermined time.

[0015] blowoff device according to claim 3, in blow-off device according to claim 1, further comprising a means for detecting the electrostatic <br/> load volume you outflow from the charge amount or blow-off cells flowing into the blow-off cell, In addition, sucking air from below
The feature is that the suction pressure can be changed.

[0016] blowoff device according to claim 4, in blow-off device according to claim 1, further comprising a means for detecting the electrostatic <br/> load volume you outflow from the charge amount or blow-off cells flowing into the blow-off cell, Moreover, it is characterized in that the air blowing pressure from above can be changed.

[0017]

[0018]

In the blow-off device of the present invention, a conductive mesh is provided above and below a conductive cylinder, and the conductive cylinder and the conductive mesh are electrically connected to each other, and the conductive cylinder is provided except for the opening of the mesh. Yes and the blow-off cell interior forms a closed space of the conductive mesh, and means for supporting the electrically insulated state from the other in a state where the conductive mesh <br/> Interview of the blow-off cell is substantially horizontal and, and, possess means for sucking air from below the blow-off cells, and means for blowing air from above the blow-off cells, and, blowing the air
As the means for applying, air is blown to a part of the above conductive mesh.
With a nozzle that sticks, and a nozzle that blows the air
Relative to the conductive mesh while maintaining a distance from each other
And blow air over the conductive mesh.
And a two-component developer consisting of a toner and a carrier is placed in the blow-off cell,
By sucking air from below the blow-off cell and blowing air from above the blow-off cell, the toner and the carrier can be separated, and only the toner can be taken out of the cell by the suction means. At this time, since the air is blown and sucked at the same time, the air flow does not flow in one direction in the blow-off cell and the toner is not scattered around. Particularly, if the air suction from the lower side is started and the air blowing is started from the upper side after a lapse of a certain time, the toner is prevented from scattering and the toner can be surely sucked.

The size of the conductive mesh of the blow-off cell allows the toner to pass, but the size of the carrier does not, and the charged toner separated by the air blow passes through the conductive mesh as described above to suck the toner. , But the carrier remains in the cell. Therefore, the toner density can be measured by measuring the amount of toner sucked by the suction means or the carrier weight after air blowing. Further, since the blow-off cell is electrically supported by the supporting means in an electrically insulated state with the conductive mesh being substantially horizontal, the carrier in the cell after the air blow is equivalent to the amount of the charged toner carried away. , The electric charge Q of the opposite polarity remains. Therefore, by measuring the change in the potential of the blow-off cell before and after the air blow, by multiplying this by the capacitance between the blow-off cell and the ground, it is possible to know the charge amount q carried away by the toner by the blow. Then, this charge amount q is divided by the weight difference between the blow-off cells (including the developer) before and after the air blow to obtain (the average of) the specific charge amount q / m of the toner. Furthermore, the air blowing pressure of the air of the intake suction pressure and the upper from the lower during air blowing, by repeating the measurement of the above with gradually increasing from a low value to a high value, to measure the charge distribution of the toner be able to.

[0020]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below based on the illustrated embodiments. FIG. 1 shows a conceptual diagram of the basic configuration of a blow-off device according to the present invention. In FIG. 1, reference numeral 1 is a holder for supporting the electrically conductive mesh 2b of the blow-off cell 2 in an electrically insulated state from the other in a substantially horizontal state,
The holder 1 is made of an insulating material such as resin and has a shape in which a circular trapezoidal holding portion 1a is fixed on a cylindrical body portion 1b, and a circular trapezoidal shape on which the blow-off cell 2 is placed. A part of the holding portion 1a is provided with a stylus for electrically connecting the cell 2 and the electrometer 7. Although not shown, a shield (punch metal or the like) covering the holder 1 and the cell 2 is provided in some cases. An opening communicating with the hollow portion of the cylindrical body portion 1b is provided at the center of the holding portion 1a of the holder 1, and the hose portion of the air suction device 3 connected to the other end side of the cylindrical body portion 1b. Air can be sucked from below the blow-off cell 2 via 3a. An air cleaner or other exhaust (suction) device can be used as the air suction device 3, and the suction force ( suction pressure ) can be changed by providing a means for varying the power supply voltage of the air suction device or an air bypass. It has become.

The blow-off cell 2 is a cylindrical conductive container 2a to put the two-component developer which is a sample to be measured, the conductivity of a predetermined numerical aperture at a predetermined opening length above and below the conductive container 2a Mesh (eg # 635 mesh, aperture 2
0 μm, aperture ratio 25%) 2b, and the conductive tube 2a
And the conductive mesh 2b are electrically connected to each other, and the inside of the conductive cylinder and the conductive mesh forms a closed space except for the opening of the mesh. For example, the volume is about 1c.
m ³ .

Blow-off cell 2 held by holder 1
A nozzle 4a of an air blower 4 as a means for blowing air from above the blow-off cell 2 is arranged above the. In addition, the nozzle 4a of this air blower 4
In a supporting portion (not shown) of the blow-off cell 2, a rotation (swirl) mechanism 4b for rotating (swirling) the nozzle 4a with respect to the mesh surface of the blow-off cell 2 so that an air jet sweeps the mesh surface, and a nozzle. There is provided a contact / separation mechanism 4c that moves the nozzle 4a up and down to change the distance between the nozzle 4a and the mesh surface of the cell 2, and it is possible to change the air blowing pressure and the blowing position from above. It is like this.

A mercury manometer 5 is connected to the cylindrical body 1b of the holder 1 via a rubber tube or the like so that the air suction force (pressure) can be measured.
Further, the suction force adjusting means of the air suction device 3, the air blower 4, and the moving mechanism (turning and contacting / separating mechanism) of the nozzle 4a are controlled by the controller 6.

In the blow-off device having the structure shown in FIG. 1, the suction pressure by the air suction device 3 is measured by using the mercury manometer 5. Then, the controller 6 manually adjusts the suction pressure level and the air jet strength by changing the height of the nozzle 4a by the controller 6. Also,
The nozzle 4a swirls on the mesh of the blow-off cell 2 so that an air jet can be sprayed evenly on the mesh.

Therefore, a sample of the two-component developer consisting of toner and carrier is put in the blow-off cell 2, air is sucked from below the blow-off cell 2 by the air suction device 3, and from above the blow-off cell 2. By blowing air from the nozzle 4a of the air blower 4, an air flow from above to below the blow-off cell 2 can be generated. This air flow separates the toner from the carrier, and only the toner is transferred to the cell 2 by suction pressure. It can be taken out of the cell through the elastic mesh 2b. At this time, since the air is blown and sucked at the same time, the air flow does not flow in one direction in the blow-off cell and the toner is not scattered around.

The conductive mesh 2b of the blow-off cell 2
The size of the eyes is large enough to allow the toner to pass through but not the carrier, and the charged toner separated by the air blow passes through the eyes of the conductive mesh 2b and is sucked by the air suction device 3, as described above. The carrier remains in the cell. Therefore, the toner density can be measured by measuring the amount of toner sucked by the suction device 3 or the weight of the carrier in the cell after air blowing. Further, since the blow-off cell 2 is electrically supported by the holding portion 1a of the holder 1 in a state where the conductive mesh 2b is substantially horizontal, the carrier in the cell after the air blow is electrically charged. When the toner is removed, an equal amount of electric charge Q of the opposite polarity remains. Therefore, measuring the amount of charge or electric load volume you outflow from the blow-off cell flows into the blow-off cell 2 before and after the air blow, i.e. by measuring the change in potential blow-off cell 2 before and after the air blow by the electrometer 7, blow-off to By multiplying the capacitance between the cell and the ground, it is possible to know the amount of charge q carried by the toner by blowing. Then, this charge amount q is divided by the weight difference between the blow-off cells (including the developer) before and after the air blow to obtain (the average of) the specific charge amount of the toner.
It is possible to obtain q / m.

Next, FIG. 2 is a perspective view of a blow-off device showing another embodiment of the present invention, and FIG. 3 is a sectional view showing a basic structure around a blow-off cell of the blow-off device shown in FIG. In the embodiment shown in FIGS. 2 and 3, an Al-made box 9 having a closed structure is placed on the XY table 8, and
A cylindrical holder 1 made of an insulating material (such as PTFE resin) is fixed to the upper surface of the box 9. An opening is provided on the upper surface of the Al box 9 and communicates with the hollow portion of the holder 1. A suction port is provided on one side surface of the Al box 9, and a hose 3a of an air suction device (not shown) such as an air cleaner is connected to the suction port. The Al box 9, the holder 1, the cell 2 and the like are surrounded by shield members 11 on all sides.

The blow-off cell 2 is provided on the upper surface of the holder 1.
There are held, blow-off cell 2 is a cylindrical conductive container holding the two-component developer which is a sample to be measured, predetermined opening at a predetermined opening length above and below the cylindrical conductive container 2a A conductive mesh (for example, # 635 mesh, opening 20 μm, opening ratio 25%) 2b, and the conductive container 2a and the conductive mesh 2b are electrically conductive to each other, except for the opening of the mesh. The interiors of the container 2a and the conductive mesh 2b form a closed space. Moreover, contact fingers for electrically connecting the blow-off cell 2 and the electrometer 7 are provided at three positions on the upper surface of the holder 1, and the electrometer 7 can measure the potential of the blow-off cell 2. it can. Further, a small-diameter hole is formed in the side wall of the holder 1, a hard rubber tube is connected to the hole, and the other end side of the rubber tube is connected to an electronic manometer (not shown). Has been done. Therefore, the suction pressure below the blow-off cell is measured by the electronic manometer. By feeding back the detection signal of the manometer to the controller as shown in FIG. 1, for example, the suction pressure of the air suction device can be automatically controlled. That is, the suction pressure can be controlled by using a variable power source such as a sliderac in the power source unit of the air suction device and controlling the variable power source by the controller according to the detection signal of the manometer.

Blow-off cell 2 held by holder 1
A nozzle 4a of an air blower serving as a unit for blowing air from above the blow-off cell 2 is disposed above. In the figure, only the nozzle part is shown.
The nozzle 4a is connected to an air blower via a rubber tube, but the air blower is not shown. The nozzle 4a for blowing the air jet is supported by a contacting / separating mechanism 10 for moving the nozzle up and down, and the space between the blow-off cell 2 and the mesh surface can be changed. In addition, the Al to which the holder 1 is fixed
Since the base portion of the box 9 is placed on the XY table, the nozzle 4a that blows an air jet vertically
The blow-off cell 2 can be moved relative to the horizontal direction. In addition, the contact / separation mechanism 10 of the nozzle 4a and the XY
The table moving mechanism can be automatically controlled by a controller (not shown).

Next, an operation example at the time of measurement using the blow-off device having the structure shown in FIGS. (Operation Example 1) FIG. 4 is a timing chart showing an operation example of the blow-off device. In FIG. 4, the operation from t _{0 to} t ₁₀ is as follows. t ₀ : Start button “ON” (nozzle descends from home position, air suction starts, indicator lights on controller during operation). t ₁ : The nozzle set height h ₃ is reached. t ₂ : Air blow "ON" (3 sec: Can be changed according to the time required for stable air suction). t _3: (also acceptable t ₂ at the same time) X-Y table swirling motion A → B start. t _4: X-Y table swirling motion A → B end. t _5: nozzle re-drop start. t ₆ : Arrived at the nozzle set height h ₅ . t _7: X-Y table swirling motion B → A start (t ₆ and availability at the same time). t _8: X-Y table swirling motion B → A the end. t ₉ : Nozzle rise start, air blow / air suction “OF”
F ″. T ₁₀ : The nozzle arrives at the home position and the operating indicator is turned off. In the above operation example, the heights h ₃ and h ₅ of the air nozzles are preset values.

In this operation example, the suction of air is started at the same time when the start button is pressed at t ₀ . Further, the nozzle starts moving toward a predetermined height. Then t ₁
At, the nozzle reaches a predetermined height h ₃ , but no air blow is performed. Then, at t ₂ (after the air suction pressure reaches a predetermined value), the air blow is started. That is, in this operation example, air suction from below the blow-off cell is started, and after a certain time has elapsed, air blowing from above is started (claim 2).

When a developer having a high toner concentration is used as a sample and suction and air blowing are performed at the same time, air is blown in a state where a large amount of toner is present on the surface of the developer, but in general, blowing is faster than suction. The air that has risen and is sometimes blown back may be bounced off by the developer layer and may fly up the toner. This may not only pollute the surroundings of the mechanical device but also impair the health of the person performing the measurement work. Therefore, as in this operation example, by starting the suction side first, the suction pressure becomes sufficiently high, and the toner that can be collected only by suction is blown with the toner removed from the developer, so that the toner is prevented from scattering. Can be prevented.

(Operation Example 2) FIG. 5 is a timing chart showing another operation example of the blow-off device. This operation example, the nozzle positions are fixed in the home position, an example in which was repeated the same operation by changing the suction pressure of air into five stages of P ₁ to P ₅ (step 1-5), FIG. In 5, the operation from t _{0 to} t ₇ is as follows. t ₀ : Start / restart button “ON” (start of air suction, indicator of operating controller lights up). t ₁ : After stable air suction (about 3 seconds), the variable power source of the air suction device is driven “ON” (boosting). t _2: When the measurement value by the manometer air suction pressure matches the set value, (air suction at set pressure) slidax driven "OFF". t _3: (also acceptable t ₂ at the same time) X-Y table swirling motion A → B start. t _4: X-Y table swirling motion A → B end. t _5: X-Y table swirling motion B → A start (t ₄ and is acceptable at the same time). t _6: X-Y table swirling motion B → A the end. t ₇ : Air suction “OFF”, indicator off during operation.

In the above operation example, the set pressure P _i (i = 1 to 1)
5) can be set (changed) on the operation panel of the controller. Further, in FIG. 5, for simplification, the third operation (set pressure P ₃ ) is represented by a solid line, and only the time t ₂ at which the air suction pressure reaches a predetermined value and the time t _{7 at} which the air suction is stopped are entered. There is. Further, the nozzle does not move, but the XY table moves. However, these operations are not essential to the present invention. That is, the XY table may be moved for the purpose of giving a slight vibration to the sample, or only suction may be performed in a static state as shown in the example of FIG. 6 below.

FIG. 6 shows a timing chart when the XY table does not move. In this example, the nozzle and X-
Fix the Y table and set the air suction pressure to P
_This is an example of the case where the same operation is repeated by changing the number of steps from _{1 to} P ₅ (steps 1 to 5). In FIG. 6, t ₀
The operation of ~t ₃ is as follows. t ₀ : Start / restart button “ON” (start of air suction, indicator of operating controller lights up). t ₁ : After stable air suction (about 3 seconds), the variable power source of the air suction device is driven “ON” (boosting). t _2: When the measurement value by the manometer air suction pressure matches the set value, (air suction at set pressure) slidax driven "OFF". t _3: After a predetermined time (e.g., t ₃ -t ₂ = 10sec),
Air suction “OFF”, indicator off during operation.

The operation example shown in FIG. 5 or 6 is an example in which the air suction pressure can be changed (claim 3). In this embodiment, the drive voltage of the air suction device (vacuum cleaner etc.) is changed. To change the suction pressure. However, the present invention is not limited to this, and a pressure adjusting valve may be provided in the intake passage for adjustment.

In this operation example, when the suction pressure is weak, only the toner having a small charge amount can be sucked, and the toner having a higher charge amount can be sucked as the suction pressure is increased. Therefore, the distribution of the charge amount of the toner in the developer is roughly known by measuring the weight of the toner that can be sucked in at a place where the suction pressure is low, and measuring the amount of charge flow (or inflow) at that time with an electrometer. be able to.

(Operation Example 3) FIG. 7 is a timing chart showing still another operation example of the blow-off device. In this operation example, the air suction pressure is constant and the nozzle heights are h ₁ to h ₅
This is an example in which the same operation is repeated by changing the air blowing pressure in five steps by changing the above (Claim 4). Figure 7
In, the operation from t _{0 to} t ₁₁ is as follows. t ₀ : Start button “ON” (nozzle descends from home position, air suction starts, indicator lights on controller during operation). t _1: arrive at the nozzle setting height h _{i (i} = 1~5). t ₂ : Air blow "ON" (3 sec: Can be changed according to the time required for stable air suction). t _3: (also acceptable t ₂ at the same time) X-Y table swirling motion A → B start. t _4: X-Y table swirling motion A → B end. t _7: X-Y table swirling motion B → A start (t ₄ and is acceptable at the same time). t _8: X-Y table swirling motion B → A the end. Air blow “OFF”, start of air suction device sliderac (pressure reduction). t ₉ : Nozzle rise start, air suction “OFF”. t ₁₀ : The nozzle arrives at the home position. t ₁₁ : Stops at the slider output voltage 0V position, and the operating indicator goes off.

In this operation example, the suction of air is started at the same time when the start button is pressed at t ₀ . Further, the nozzle starts moving toward a predetermined height. Then, at t ₁ , the nozzle reaches a predetermined height but does not blow air. Then, at t ₂ (after the air suction pressure reaches a predetermined value), the air blow is started. In this operation example, the nozzle height is set to h ₁
~ H ₅ is changed to change the air blowing pressure, but h _i
(I = 1 to 5) can be set (changed) on the operation panel of the controller. Further, instead of changing the height of the nozzle, a blowing pressure may be directly adjusted by using a pressure adjusting valve in the air supply passage to the nozzle.

In this operation example, when the blow pressure is weak, only the toner having a small charge amount is blown off, and the toner having a higher charge amount can be blown off as the blow pressure is increased. Therefore, the toner that has been blown off and sucked at a predetermined blow pressure is weighed, and the amount of charge flow (or inflow) at that time is gradually increased from a low blow pressure location (h ₁ ) (up to h ₅ ) By repeatedly measuring with an electrometer, the distribution of the charge amount of the toner in the developer can be roughly known.

(Operation Example 4) Next, using the blow-off device having the configuration shown in FIGS.
Move the table 8, as an operation example of <br/> field if changing the relative position of blow-off cell 2 and the nozzle 4a so as to be blown substantially constant amount of air across the mesh surface strung blow-off cell 2, FIG. 8 shows the locus (relative position) of the nozzle on the XY plane with respect to the blow-off cell.

In FIG. 8, the point A (0, 16) is the start point of the vortex motion, and the point B (16, 0) is the end point. If the diameter of the mesh surface of the blow-off cell is φ25, point A (0,
16) is outside the mesh plane. Generally, in a device that stores compressed gas in a tank and controls air blow by opening and closing a valve, the flow velocity immediately after the start of air blow is higher than the stable flow velocity. That is, there is a protrusion phenomenon. Therefore, the set pressure is set to start at this point A. By doing so, it is possible to prevent the charge amount of the toner blown off by the protrusion of air from changing depending on the location.

The linear velocity of the relative movement between the nozzle 4a and the XY table 8 is constant, and the distance between the trajectories is almost constant. In addition, a return: a locus when going from the center to the outside passes through an almost center of a trail: a path when going from the outside to the center.
In the timing charts of FIGS. 4, 5 and 7 described above, the inner winding represents the movement from the outer side of the outward movement toward the center, and the outer winding represents the movement from the center of the return toward the outer side. There is. Furthermore, not only the movement from position A to B,
There is also a movement from position B to A. From the position B to the position A, the locus of FIG. 8 is moved along a locus in which the straight line Y = X is mirror-inverted. Although the blow-off cell is moved by using the XY table in this embodiment, the nozzle may be moved by the turning mechanism as described in the configuration example of FIG.

Now, in this operation example, an air jet of a substantially constant amount can be blown toward the mesh surface on the upper surface of the blow-off cell during the sweep period of a certain step. As a result, air having a substantially constant flow velocity and flow rate flows in the sample developer layer, and the toner having substantially the same adsorption force (with respect to the carrier) can be peeled from the entire sample developer. Therefore, it is possible to reliably measure the average charge amount and the charge amount distribution of the toner.

[0045]

As described above, according to the present invention, there is provided a blow-off device capable of easily obtaining the toner concentration of a two-component developer, the average charge amount of the toner, and the charge amount distribution with a relatively simple structure. can do. Moreover, since the blow-off device according to the present invention includes the means for sucking air from the lower part of the blow-off cell and the means for blowing air from the upper part of the blow-off cell, the air flow flows in one direction in the blow-off cell to remove the toner. The toner that has passed through the mesh of the blow-off cell can be reliably collected on the suction unit side without being scattered around.
Also, as in claim 2, the suction side is started first,
By starting blowing in a state where the suction pressure is sufficiently high and the toner that can be collected only by suction is removed from the developer, it is possible to prevent the toner from scattering.

Furthermore, the electric charge flowing into the blow-off cell
Means for measuring the amount or blow-off cell electric load volume you flow out provided, and can change the air suction pressure as claimed in claim 3, or to allow change the air blowing pressure as claimed in claim 4 As a result, it is possible to easily measure the outline of the charge amount distribution of the toner. Moreover, by having means for varying the relative position of the blow-off cell and the nozzle to be blown substantially constant amount of air across the mesh surface strung Bed Roofuseru, through the sample developer layer flow velocity and flow rate substantially constant Air flows from the entire sample developer
It is possible to peel off the toner having substantially the same adsorption force (with respect to the carrier), and it is possible to reliably measure the average charge amount and charge amount distribution of the toner.

[Brief description of drawings]

FIG. 1 is a conceptual diagram of a basic configuration of a blow-off device showing an embodiment of the present invention.

FIG. 2 is a perspective view of a blow-off device showing another embodiment of the present invention.

3 is a cross-sectional view showing a basic configuration around a blow-off cell of the blow-off device shown in FIG.

FIG. 4 is a timing chart showing an operation example of the blow-off device according to the present invention.

FIG. 5 is a timing chart showing another operation example of the blow-off device according to the present invention.

FIG. 6 is a timing chart showing still another operation example of the blow-off device according to the present invention.

FIG. 7 is a timing chart showing still another operation example of the blow-off device according to the present invention.

FIG. 8 is an explanatory diagram of an operation example of the blow-off device according to the present invention, and is a diagram showing a locus (relative position) of the nozzle on the XY plane with respect to the blow-off cell.

[Explanation of symbols]

1: Holder 2: Blow-off cell 2a: conductive container 2b: Conductive mesh 3: Air suction device 3a: Air suction hose 4: Air blower 4a: nozzle 5: Mercury manometer 6: Controller 7: Electrometer 8: XY table 9: Al box 10: Nozzle contact / separation mechanism

─────────────────────────────────────────────────── ─── Continuation of the front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) G01N 27/60 G01R 29/24

Claims (4)

(57) [Claims] 1. A conductive cylinder and a conductive mesh are provided above and below a conductive cylinder, and the conductive cylinder and the conductive mesh are electrically connected to each other, and the conductive cylinder and the conductive mesh are separated except for the opening of the mesh. A blow-off cell whose inside is a closed space; and a means for supporting the electrically conductive mesh of the blow-off cell in an electrically insulated state from the other in a substantially horizontal state, and
Means for sucking air from below the blow-off cell,
Have a means for blowing air from above the blow-off cells, and, means for blowing the air, said conductive
Has a nozzle that blows air onto a part of the flexible mesh.
Of the air and the conductive mesh
It is possible to move relatively while maintaining the distance of
A blow-off device characterized by being able to blow air over the entire unit. 2. The blow-off device according to claim 1, wherein
A blow-off device, which starts sucking air from below and starts blowing air from above after a certain period of time. 3. The blow-off device according to claim 1, wherein
And means for detecting an electric load volume you outflow from the charge amount or blow-off cells flowing into the blow-off cell, and, blow-off device, characterized in that capable of changing the air intake suction pressure from below. 4. The blow-off device according to claim 1, wherein
And means for detecting to that electric load volume flows out from the charge amount or blow-off cells flowing into the blow-off cell, and, blow-off device, characterized in that capable of changing the air blowing pressure from above.