JPS58208770A - Device for detecting toner density of developer - Google Patents

Abstract

PURPOSE:To improve detecting accuracy by comparing the value of an electric current flowing into a developer stored in a reference developer case with the value of a current flowing into a developer on a sleeve. CONSTITUTION:Voltage is applied to a developer over the sleeve 3 of a magnetic brush developing device using a dry type developer consisting of two components and the toner density of the developer is detected by the current value. The developer with the reference toner density for comparison is stored in the reference developer case 13 having a conductive part. The developer with the reference density is arranged on almost the same environmental position as the developer in a toner density detecting part on the sleeve 3 and DC voltage is applied to compare the value of current flowing into the developer in the reference developer case 13 with the value of current flowing into the developer on the sleeve 3. By comparing these current values with each other, the toner density is detected.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a toner concentration detection device for a developer in a photocopying machine using a dry two-component developer consisting of toner and carrier.

Conventionally, one of the methods for detecting the toner concentration of a dry two-component developer is the
As shown, along with applying a magnetic field to the developer,
Applying another field in the same direction as this magnetic field, the current flowing through it
f: There is a method of detecting the toner concentration of the developer by measuring it.

This conventional method has the advantage of being less affected by the degree of clogging of the developer, but the inventor's experiments have shown that the current flowing through the developer, that is, the resistance value of the developer, changes with humidity. It has been found that there is a problem in that it is difficult to detect a stable toner concentration because the detection level of toner viscosity is affected by humidity extremely strongly. In order to solve the problems with the toner temperature detection method, we developed a l-toner that is not affected by the humidity around the developing device and can stably and accurately detect the toner temperature of 61 degrees. This is an attempt to provide a rockyness detection device a.

The developer toner detection device a of the present invention applies a voltage to the developer on the sleeve of a magnetic brush developing device using a dry two-component developer so that 'i!' flows. In the toner yield detection device that detects the toner concentration of the developer based on the L flow value, a reference developer container having a ventilation part stores a developer containing a reference toner for comparison, and this developer is used to detect the toner concentration of the developer on the sleeve. The concentration detection section is placed at a position in almost the same environment as the developer, and a DC voltage is applied, and this base $ tJt in the developer container is
The special feature is that the toner degree can be detected by comparing the current sensitivity flowing through the developer on the sleeve with the 'lfi bt value that passes through the developer. , a magnetic brush iJ! incorporating an embodiment of the toner detection device of the present invention whose main part is shown in FIG.
, a schematic diagram showing an example of the configuration of an imaging device/4fr r
#i is a diagram.

In the same figure, the developer in the agent container l is collected by placing a plurality of permanent magnets long in the axial direction on the identified cylinder f7 L, and 1. , due to the magnetic force of the magnetic roll 2,
Sleeve 8 that rotates concentrically with respect to the magnetic roll 2
As the sleeve 8 rotates, the sleeve 8 is sent in both directions in the direction of the arrow a, and after being regulated to a constant N thickness by the doctor blade 4, it comes into contact with the photoreceptor 6 at the position of the developing magnetic pole 5. The electrostatically deposited image formed on the photoreceptor 6 is developed. The developer that has contributed to the developing chamber is scraped off from the surface of the sleeve 8 by the scraper 7, falls onto the stirring member 8, is stirred and conveyed by the stirring member 8, and is deposited on the sleeve 3 again. , the rotation of the toner replenishment row 29 causes the toner hopper □ to flow from 10 to the current 1.
The toner co-fed into the developer container I is stirred and mixed with the developer scraped off the sleeve 8 by the scraper 7.

Therefore, the permanent magnet 11 in the magnetic roll l and the sleeve 8
A toner detection electrode 12 having a shape extending in the axial direction of the sleeve 8 is provided at a position facing the sleeve 8 . The permanent 6 yoshiki is not directly involved in the development, but the sleeve 8
This is for conveying the upper developer, and the magnetic pole faces the direction of the straight pole 12 for toner one-time detection. Therefore, the developer that adheres to the sleeve 8 and is sent to the position of the permanent stone 11 is the drowsy brush? j: Formed and brought into contact with the toner concentration detection device 112. A direct current voltage of approximately 160 V is applied to the sleeve 8 from a direct current source (not shown), and since the city pole 12 for detecting fallen toner is also grounded, the magnetic field formed by the permanent magnet 11 A current flows through the two bristles of the brush. The m value varies depending on the toner concentration of the developer, and Mg is the applied vehicle pressure of 16
(In the case of IV, 1M degree, 25°C, 1 humidity [5σ temperature, RH, the developer of the powder carrier will change as shown in Figure 2. Even with moderate humidity, the toner yield rate will be 8.5%. In the case of , it changes as shown in FIG.

In order to accurately obtain the detection output of the toner yield without being affected by humidity, the main part of this embodiment is As shown in the figure, a developer having a reference toner for comparison is stored in a base 1vA developer trough 18 having a vent, and the toner detection pole 12 and the permanent magnet 11 of the magnetic roller 2 described earlier are used.
The toner at the position facing the developer on the sleeve 6 in the detection section 1a is exposed to almost the same atmosphere.
The reference developer container 18 is placed at.

The appearance of one example of each member of the reference developer container 13 is shown in FIGS. 5A and 5H. As shown in the figure, the reference developer container 18 is a kind of box, and inside the reference developer container 18 is a developer having the same reference toner concentration as the developer that adheres to and moves on the sleeve 8 (see FIG. 4). is accommodated.

Further, the upper surface iaa and the lower surface 181) of the container 18 are in contact with electrodes, and at least the lower surface 18b is covered with an electrode to prevent the reference toner concentration developer from spilling out of the container. The other four sides are sleeve 8
It is made of an insulating material to prevent the upper developer from entering. Furthermore, this reference developer container 18 includes
The container 18 has a ventilation section for placing the reference toner-summer developer in the container 18 in the same atmosphere as that in the case where the container 18 is placed.

The one in Fig. 5A has a structure in which an external/X-hole exchange window 14 is formed on the side as a ventilation part, and the one in Fig. 5B has a structure in which the electrode on the upper surface 18a is formed into a mesh-like electrode. This allows a ventilation section to be formed.

As shown in FIG. 4, the base developer container 18 constructed in this manner is connected to the permanent stone 11 of the magnetic roller 2 so that the electrode on the lower surface 181) faces the toner concentration detection electrode 12. On the other hand, they are placed opposite to each other with the sleeve 3 interposed therebetween, and at a distance slightly away from the sleeve 8 in order to prevent friction with the sleeve 8.

It is. Therefore, the reference toner developer in the reference developer container 13 is detected by the permanent magnet 11 in the magnetic roll z facing the toner concentration detection electrode 12, similarly to the developer on the sleeve δ. The spikes stand in the container 18 and are in contact with the electrodes forming the upper surface 18a of the container 18. On the other hand, the same voltage as the voltage applied to the sleeve 3 is applied to the electrode forming the lower Htab of the reference developer container 13.
The current flowing by supplying from the DC core source 15 and grounding the electrode corresponding to the upper surface 1aa of the container i18 is detected using the vehicle pressure drop caused by the resistor 16.The reference in the reference developer container 18 is detected. The developer for toner density is
Through the ventilation M provided in the container 18, its resistance value changes under almost the same environment or atmosphere as the developer on the sleeve 8, especially under the same humidity, so that the resistance value obtained by the resistor 16 changes. voltage and toner concentration detection electrode 1
Each of the m pressures detected by the conventional method of PJ is detected by the voltage drop across the resistor 17 due to the current from 2.

If it is led to the comparator 18 and compared, the detected ft4
The signal output terminal 19 outputs the current value on the sleeve 8 based on the toner hardness of the reference toner hardness developer without being affected by changes in the resistance value of the developer due to changes in humidity.
Comparison output is obtained for one dose of cheap toner. Therefore, by this comparison output, the 101 rotations of the toner replenishing roller 9 in the developer container 1 can be maintained at approximately the same toner concentration as the weaving developer.

The humidity If:'f in the container 18 may be formed of a material that can maintain the same humidity as the surrounding humidity without entering the container 18,
Furthermore, the number of windows may be provided on any of the four sides, and the number of windows is not limited to one.

@Diagram B is a schematic cross-sectional diagram showing the configuration of another embodiment of the present invention, and the same parts as in FIGS. 1, 4, and 5 are designated by the same reference numerals. be.

In this embodiment, the inside of the developer container 1 is the same environment as described in the above-mentioned example. ! ! By providing the quasi-developer container 18 on the inner surface of the developer container 1 at a position close to the "sensing electrode 12G" for toner concentration detection, the structure is made easier to understand. The +74 configuration of the pond has the same configuration as that of the deletion implementation array described in FIGS. 4 and 5.

Each resistor 16.1 controls the current flowing through the base toner concentration developer in the reference developer I8 on the inner wall of the container I.
7 is converted into vehicle pressure, and comparison 518 is used to detect the toner concentration.

In this case, the standard toner hardness developer in the standard developer container 13 does not stand up like the Jlj agent on the sleeve 3 in the IR at the level of the toner hardness detecting plate 12; Since it is under almost the same environment as the phenomenon agent on the sleeve 3,

The change in the resistance value of the reference toner and the developer in the sleeve 8 corresponds to the change in the resistance value of the developer on the sleeve 8 .

Therefore, when comparing the currents flowing through the respective developers using the comparator 18, each resistor 16, 17 (if set appropriately), the developer on the sleeve δ is independent of the influence of the environment. Toner transfer Rt of standard toner developer
The specific soft output is obtained based on . Therefore, it is possible to control the rotation of the toner 111f supplying roller O in the developer container 1 using this comparative output as in the case of the +11th embodiment.

As is clear from the explanatory power of the above-mentioned embodiments, according to the present invention 1, the present invention is arranged in the developer device path in which the toner density is to be detected, and the m flow of the developer having the reference toner density is provided. Since the value is compared with the value of the α flow flowing through the developer to be used to detect the toner, it is possible to detect changes in the atmosphere inside the imaging device, such as changes in humidity. It is possible to obtain stable toner concentration detection output.
Furthermore, the degree of detection is also effective.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional diagram schematically showing the configuration of a magnetic brush developing device incorporating the uninvented toner-once detection device a, and FIG. 2 shows an example of a change in m flow value with respect to toner-once detection device a. A curve diagram; FIG. 8 is a curve diagram showing an example of a change in the m flow value with respect to attitude; FIG.
and B are external diagrams showing different configuration examples of the reference developer container, respectively. FIG. 6 is a sectional view showing the structure of another embodiment of the present invention in outline and diagrammatic form. ■...Developer container 2 2...Magnetic roller 8...Sleeve 5, 11...Permanent magnet 9...Toner thickener 12...Toner thickness detection electrode 1
8...Reference developer volume Hxaa...Top surface 18 b...
・Bottom surface 14... Outside air window 15...
DC Ryugen 16, 17...a M ##1
8... Hiei story 19... Detection signal m terminal. Special Fl-tB &11' 1 person Olympus Optical Industry Co., Ltd. District map Figure 2 Figure 3 Humidity (〃RH) (3! 8th 1, Indication of the case 1988 Special Request No. 104.83 2, Name of the invention Developer toner concentration detection device 3, Person making the correction Patent applicant related to the case (OA7) Olympus Optical Industry Ltd. (corrected diagram) Figure 6

Claims (1)

[Claims] #1 on the sleeve of a magnetic brush developer using dry two-component #L developer. In a toner degree detection device that detects the toner concentration of the developer based on the current value that flows by applying a voltage to the developer, a developer having a reference toner error level for comparison is placed in a reference developer container having a vent. This is placed in a position in almost the same environment as the developer in the toner missing detection section on the sleeve, and a DC voltage is applied, and the current value flowing through the developer in this reference developer container and the developer on the sleeve are 1. A toner concentration detection device for a developer, characterized in that the toner concentration is detected by comparing the current value flowing through the developer.