JPS59147369A - Developing device - Google Patents

Abstract

PURPOSE:To prevent a developer from being napped on a detection coil by arranging an auxiliary conveyance pole with a different magnetic polarity between two magnetic poles, i.e. a separating pole and the 1st development pre-conveyance pole on an included angle side. CONSTITUTION:The included angle theta between the separating pole 12 and the 1st development pre-conveyance pole 8 is set to 110 deg.<=theta<=130 deg. and an attracting pole 18 and the auxiliary conveyance pole 19 are provided dividing the angle almost equally. Therefore, a magnetic body iron core 17 in a toner mixing ratio detector is never magnetized by lines of magnetic force. Thus, no developer 3 is napped on the detection coil 16. Further, the developer at this part is returned smoothly, so a measurement of a toner mixing ratio is taken accurately.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a dry type developing device that can be applied to electrophotographic copying machines, facsimiles, and printers.

Conventional configuration and problems Conventionally, as a device for developing an electrostatic latent image on the surface of a photoreceptor using a magnetic developer, a fixed magnetic pole is placed inside a rotatable developing sleeve made of a non-magnetic material. (~, There is a sleeve rotating type that develops the electrostatic latent image formed on the photoreceptor with a magnetic brush that is formed by rotating the developing sleeve and conveying the developer. In addition to the N-polarity development pole, there are two N-pole magnetic poles, a first pre-development transport pole and a separation pole, as magnetic poles for developer transport and separation, and these two magnetic poles In order to adsorb the developer between the included angle sides of the
2. Description of the Related Art A developing device is known that has either a pole or a south pole adsorption pole. However, there are several problems in actually using this method. A conventional developing device will be described below with reference to the drawings.

FIG. 1 is a block diagram of a conventional developing device, in which 1 is a photoreceptor;
2 is a developing container. The developer 3 is stirred within the developer container 2 by a stirring member 4 .

The developer 3 is attracted to the developing sleeve 6 by the suction electrode 6, is transported in the direction of the arrow, is regulated to stand up by a regulating blade door, and is developed by the first pre-development transport pole 8 and the second pre-development transport pole 9. The image is transported in a 10-inch area and developed.

The developer 3 that has been developed is transported by the pre-development transport pole 11 to the separation pole 12 , where it is separated from the development sleeve 6 by the scraper 13 and collected into the developer container 2 . On the other hand, the overflowing developer is regulated by the regulating blade 7 and is refluxed on the reflux plate 14 and collected into the developing container 2. However, in the above configuration, the adsorption electrode 6
Under the influence of the magnetic lines of force generated on the bridge and the first pre-development transport pole 8, the developer 3 stagnates on the current plate 14 and is hardly refluxed. If the magnetic force of the attracting pole 6 is weakened by a certain amount, the conveying force of the developer 3 will be reduced or even be completely weakened.

FIG. 2 is an improved version of this, and the same parts as in FIG. 1 are given the same symbols. The polarity of the adsorption electrode is opposite to that in FIG. The flow of the developer 3 is similar to that shown in FIG. 1, but since there are no lines of magnetic force bridged between the adsorption pole 16 and the first pre-development transport pole 8, the developer 3 does not stagnate on the reflux plate 14 but refluxes. However, as illustrated in FIG. 2, the magnetic force lines of the attracting pole 15 magnetize the magnetic iron core 17 in the detection coil 16 of the toner mixture ratio detection device in a direction nearly perpendicular to the reflux plate 14. becomes a standing state and the magnetic iron core 17
This method has the drawback of impeding the flow of the soil developer and significantly reducing the ability to measure the toner mixing ratio. Another drawback is that if the magnetic force of the attraction pole 16 is weakened, the conveyance force of the developer 3 will be reduced or the life of the developer 3 will be completely exhausted.

Object of the Invention The object of the present invention is to provide an attraction pole between the narrow angle sides of two magnetic poles, a separation pole and a first pre-development transport pole, in a magnet roll, and at least one magnetic pole different from the attraction pole. By arranging a conveyance auxiliary pole with a magnetic field, determining the angle between the separation pole and the first pre-development conveyance pole, the positions of the adsorption pole and the conveyance auxiliary pole, and determining the magnetic force of the magnet roll, the above drawbacks can be solved. An object of the present invention is to provide a developing device in which the above problems are eliminated.

Structure of the Invention In order to achieve the above object in the developing device of the present invention, a magnetic roll built in a rotatable non-magnetic developing sleeve is used to develop a developer mainly composed of a magnetic carrier and an insulating toner. When developing the electrostatic latent image formed on the photoconductor, the developing sleeve is rotated from above to below with respect to the contact surface between the developer and the photoconductor, and a magnetic brush is formed on the photoconductor. As for the arrangement of the magnetic poles, a separation pole, an adsorption pole, and at least one transport auxiliary pole are arranged in this order in the stirring region, and a first pre-development transport pole is arranged in this order in the pre-development region. A regulating plate 1 for regulating the height of the developing layer on the developing sleeve is provided near the developing sleeve of the transport auxiliary pole which is close to the pole and the first pre-development transport pole. A developing device is provided, characterized in that a reflux plate for refluxing the developer and a toner mixture ratio detection device for the developer are provided in the vicinity of the auxiliary transport pole that is close to the first pre-development transport pole. It is something.

DESCRIPTION OF EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. The same parts as in Figures 1 and 2 are marked with the same symbols.

In FIG. 31, the flow of the developer 3 is almost the same as in the conventional example shown in FIG. ≦130
At the same time, the adsorption pole 18 and the conveyance aid 19 are provided at positions that almost equally divide this angle. The iron core 1 is not magnetized.As a result, the developer 3 does not form spikes on the detection coil 16 and flows over the return current plate 14 and the detection coil 16.

Unfortunately, since the detection surface of the detection coil 16 is arranged to be the same or almost the same surface as the reflux plate 14 (0 developer receiver), there may be no change in the original structure or characteristics of the developer. The toner mixture ratio can be detected in a uniform developer state at all times.The detection coil 16 used for detecting the toner mixture ratio includes a magnetic iron core 17 having an open magnetic path in the direction in which it contacts the developer 3.
It has a structure in which a winding 20 is applied to the terminal 21 and a change in inductance between the terminals 21 is detected.

Furthermore, the magnetic force of the magnet roll 22 is
00 to 600 Gauss, adsorption electrode 18 and transport auxiliary electrode 19
260 to 350 gauss, 60 gauss at first pre-development transport pole 8
0 to 9o○] and the magnetic poles are arranged as described above. As shown in FIG. 3, the developer 3 is stirred in the developer container 2 by the stirring member 4 without being affected by the magnetic lines of force caused by the first pre-development transport pole 8 and the transport auxiliary pole 19, and the transport force is reduced. There's nothing to do.

In the above embodiment, the developing pole 23 is the N pole, and the post-developing transport pole 1 is the N pole.
1 is the S pole, the separation electrode 12 is the N pole, the adsorption electrode 18 is the N pole (even, the transport auxiliary pole 19 is the S pole, the first pre-development transport pole 8 is the N pole, and the second pre-development transport pole 9 is the S pole). The pole ζ is the developing pole 23
pole, the post-development transport pole 11 is the N pole, the separation pole 12 is the S pole, and the first
It is also possible to make the pre-development transport pole 8 the south pole and the second pre-development transport pole 9 the north pole. Note that the attracting pole 18 and the conveying auxiliary pole 19 can be applied to any of the above cases as long as the polarities of the two magnetic poles are different.

Effects of the Invention As is clear from the above explanation, the present invention provides an adsorption pole between two magnetic poles, a separation pole and a first pre-development transport pole, and an adsorption pole between the narrow angle sides of the pole, and at least one phase attached to this adsorption pole. By arranging transport auxiliary poles with different magnetic poles, the magnetic iron core of the toner mixture ratio detection device is not affected by the magnetic lines of force of the attracting pole, so it is not magnetized and the developer does not flow on the detection coil. I often stand up. As a result, excellent effects such as smooth reflux of the developer in the area and accurate measurement of the toner mixture ratio can be obtained. However, since it is not affected by the magnetic lines of force of the adsorption pole and the first pre-development transport pole, excellent effects such as smooth stirring of the developer can be obtained. Furthermore, if the angles and magnetic force between the separation pole, attraction pole, transport auxiliary pole, and first pre-development transport pole are defined, it will be even more effective to prevent the transport force from decreasing.

[Brief explanation of the drawing]

1 and 2 are sectional views of a conventional developing device, FIG. 3 is a sectional view of a developing device according to an embodiment of the present invention, and FIG. 4 is an I
- It is an enlarged cross-sectional view of the main part of the mixture ratio detection device. 1...Photoreceptor, 2...Developer container, 3...
Developer, 4... Stirring member, 6... Developing sleeve, 7... Regulation blade, 8...
・First pre-development transport pole, 9... Second pre-development transport pole,
1o... Development area, 11... Post-development transport pole, 12... Separation electrode, 13... Scraper, 14... Reflux plate, 16...Detection Koinope 17...Magnetic iron core, 18...Adsorption pole, 19...Transfer auxiliary pole, 20...Winding wire, 2
1...Terminal 1, 22...Magnet roll, 23...Development pole. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure 2 Figure 3 Figure 4

Claims (4)

[Claims] (1) A magnetic roll built into a rotatable non-magnetic developing sleeve is used to form a magnetic brush of developer containing magnetic carrier and insulating toner as main components, and the developer is formed on the photoreceptor. When developing an electrostatic latent image, the developing sleeve is rotated from above to below with respect to the contact surface between the developer and the photoreceptor, and as the arrangement of the magnetic poles of the magnet roll, separation poles, separation poles, etc. are provided in the stirring area. A suction electrode and at least one auxiliary transport pole are arranged in this order, and a first pre-development transport pole is arranged in this order in the pre-development area, and is close to the first pre-development transport pole and the first pre-development transport pole. A regulating blade is provided near the developing sleeve of the auxiliary transport pole for regulating the height of the spikes of the developing layer on the developing sleeve, and further, a regulating blade is provided near the auxiliary transport pole near the first pre-development transport pole on the developing sleeve. a reflux plate for refluxing the developer;
A developing device comprising a developer toner mixing ratio detection device. (2) The angle between the first pre-development transport pole and the separation pole is 11
The developing device according to claim 1, wherein the angle is greater than or equal to 0 and less than or equal to 130, and the suction electrode and the transport auxiliary pole are provided at positions that substantially equally divide this angle. (3) The magnetic force of the magnet roll is 300~ with separated poles.
500 Gauss, 260-36 for adsorption electrode and transport auxiliary electrode
2. The developing device according to claim 1, wherein the pressure is 0 Gauss and 600 to 900 Gauss at the first pre-development transport pole. (4) As a developer toner mixture ratio detection device, a detection coil made by winding a magnetic iron core with a part of an open magnetic path is attached to the reflux plate that circulates the developer, and the detection surface The development according to claim 1, characterized in that the development omitted from the reflux plate uses a toner mixture ratio detecting device for the developer disposed so that the developing surface is flush with or almost flush with the surface of the reflux plate. Device.