JPS5944074A - Toner supplying and distributing mechanism - Google Patents

Abstract

PURPOSE:To supply an irreducible necessary amount of magnetic toner into a developing device all the time and to distribute the magnetic toner to respective magnet rolls uniformly, by providing a means which detects the amount of the magnetic toner restrained on circumferential surfaces of respective sleeves of plural magnet rolls and a scraper rotatably between the magnets rolls. CONSTITUTION:An agitator 11 rotates according to the output signal of the toner amount detecting means 12 to supply the magnetic toner 9 in a toner tank 10 by an enough amount to form a uniform layer around the circumferential surface of the sleeve 5 of the magnet roll 2 until its level drops below the operation point of the toner amount detecting means 12. A solenoid 16 and a movable piece 17 operate by the output signal of the toner amount detecting means 13 to rotate the scraper 14 around a fulcrum 15, and its leading edge contacts the circumferential surface of the sleeve 5 of the magnet roll 2, so that the magnetic toner 9 is supplied onto the circumferential surface of the sleeve 5 until the level drops below the operation point of the toner among detecting means 13, i.e. until the uniform toner layer is formed.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a developing device for developing an electrostatic latent image formed on a recording medium with magnetic toner, in which magnetic toner is supplied and distributed to a plurality of magnet rolls in the device. Regarding the mechanism.

Generally, in electrophotographic recording devices and electrostatic recording devices, an electrostatic latent image is formed on a recording medium by a well-known exposure means, and a magnetic toner is attached to this electrostatic latent image to develop it and make it visible. I'm getting a statue.

Here, the term "magnetic toner" refers to a so-called -component magnetic toner in which a magnetic material is mixed into the toner itself.

The specific adhesion of magnetic toner in this development process is achieved by a magnetic brush development method using the rotation of a magnet roll installed in the development device, but higher-quality image reproduction and high-speed development are possible. Due to the necessity of It has been found that sufficient toner density can be maintained even when driven at high speed.

However, in this developing device, the following problem occurs when toner is supplied into the device provided with a plurality of magnet rolls. That is, the magnetic toner supplied from the toner supply port provided at a predetermined location of the developing device must be distributed to a plurality of magnetic rolls as necessary, as in the conventional method. It is n.

One way to solve this problem is to keep the developing device constantly filled with magnetic toner, but according to NVC, all magnet rolls are immersed in a layer of magnetic toner. The magnet roll is rotated in the same state as before, and the amount of bound toner on the circumferential surface of the sleeve that makes up the magnet roll is B.
H becomes excessive, so the rotational negative r of each red sea bream roll
Not only does the magnetic toner itself become very high and require a large drive system, but the magnetic toner itself also spends a lot of time idling in the developing device before it is actually consumed for development. The present invention aims to solve these drawbacks. A toner supply/distribution mechanism capable of efficiently producing the minimum amount of magnetic toner in a developing device having multiple magnetic rolls, and uniformly distributing magnetic toner to each magnetic roll. For this purpose, means for detecting the amount of magnetic toner bound on the circumferential surface of the sleeve of the magnet roll is disposed near a doctor blade that regulates the layer of magnetic toner on the circumferential surface of the sleeve, and
The entire feature is that means for arbitrarily transporting the magnetic toner is arranged between the magnet rolls that are in R contact with each other.

The following drawings ('Doyo J2) To explain, Fig. 1 is a side sectional view showing a first embodiment of the toner supply and distribution mechanism according to the present invention. Rotating magnet rolls 02 and 3 are developing magnet rolls placed at predetermined intervals along the circumferential surface of the recording medium 1. Each of the permanent magnets 4 is composed of alternately magnetized permanent magnets 4 and a sleeve 5 made of a non-magnetic material that covers the outer periphery of the permanent magnets 4 in a non-contact manner.
An optimum gap is set between the sleeve 5 and the recording medium 1.

6 is arranged so that the tip faces the circumferential surface of the sleeve 50 of the magnet roll 2 with a certain gap: +',
7 is a doctor blade arranged so that its tip faces the circumferential surface of the sleeve 50 of the magnet roll 3 with a certain gap in between, and 8 is a cover of the developing device containing the magnet roll 2g3 etc. , 9 is a magnetic toner, 10 is a toner tank containing the magnetic toner 9, and 11 is an agitator located at the bottom of the toner tank 10 for supplying toner.

Reference numerals 12 and 13 denote toner amount detecting means provided near the doctor blades 6 and 7, respectively.As the toner amount detecting means 12 and 13, for example, a photocoupler, an acoustic coupler, a piezo element, a Hall element, etc. are used. Sanru.

Reference numeral 14 denotes a scraper placed between the magnet rolls 2 and 3, which scrapes the magnetic toner 8 on the circumferential surface of the sleeve 5 of the magnet roll 2 onto the sleeve 50 of the magnet roll 3.
This is for guiding it onto the circumferential surface. This scraper 1
4 is rotatable around a fulcrum 15 provided in the middle, and its base end is fixed to a movable piece 17 of a solenoid 16, and this movable piece 17 is attached to a coil spring 18.
Under normal conditions, the tip of the scraper 14 is kept away from the circumferential surface of the sleeve 5 of the magnet roll 2 and is on standby.

Next, the operation of the above-mentioned structure will be explained. In FIG.
It is assumed that a predetermined area of magnetic toner 9 exists near the doctor blade 6.7 on the zero circumferential surface. In this state, the magnet rolls 2 and 3 rotate relative to each other between the permanent magnet 4 and the sleeve 5, that is, the sleeve 5 is in the direction of the arrow, and the permanent magnet 4 is in the direction of the arrow. By rotating in the respective directions, the magnetic toner 9 is conveyed in the direction indicated by the arrow.
The magnetic toner 9 is regulated by VC so as to form a single layer of toner of uniform thickness by the tip of the doctor blade drawer 7, and then the magnetic toner 9 is formed on the recording medium 1 at a predetermined position. If the developing process is continued, the magnetic material that is bound on the circumferential surface of the sleeve 5 of the magnet roll 293 will adhere to the electrostatic latent image that is spreading and will be developed. The amount of toner 9 decreases depending on the development process, and when this decrease progresses further, the amount of magnetic toner 9 on the circumferential surface of sleeve 5 decreases as the amount of magnetic toner 9 decreases depending on the development process. Although the amount of magnetic toner 9 is insufficient than the amount that can be regulated by γ to form a layer of uniform thickness, the toner amount detection means 12 and 13 are activated to supply the magnetic toner 9 just before the amount of magnetic toner 9 becomes insufficient. As a result, the magnetic toner 9 is supplied and distributed to the sleeves 5 of the magnet rolls 2 and 3.

That is, when the toner amount detection means 12 is activated, the agitator 11 is rotated by the output signal thereof, and the toner tank 1 is rotated.
Means 1 for determining the amount of magnetic toner 9 fed out
The magnetic toner 9 is supplied onto the circumferential surface of the sleeve 5 of the magnet roll 2 until the temperature reaches the operating point of 2 (n71). That is, an amount of magnetic toner 9 sufficient to form a uniform layer of toner on the circumferential surface of the sleeve 50 is supplied, and then the rotation of the agitator 11 is stopped.

On the other hand, when the toner amount detection means 13 is activated, the solenoid 16 is driven by the output signal, and the movable piece 1γ moves in the direction of arrow C against the tensile force of the coil spring 18. The center rotates to the position shown by the broken line, and its tip contacts the circumferential surface of the sleeve 5 of the magnet roll 2. At this time, the sleeve 5 of the magnet roll 2 rotates in the direction of the arrow to convey the magnetic toner 9. Then, this magnetic toner 9 is guided onto the circumferential surface of the sleeve 5 of the magnetic roll 3 by the scraper 14, and this induction is continued until the amount reaches below the operating point of the toner amount detection means 13, that is, a uniform layer of toner is formed. Then, the solenoid 16 stops, and the tension force of the coil spring 18 causes the system scraper 14 to return to its original position.

Here, when the amount of magnetic toner 9 on the circumferential surface of the sleeve 5 of the magnet roll 2 is insufficient due to the operation of the scraper 14, the toner amount detection means 12 is operated again, and the magnetic toner is removed by the agitator 11 on the circumferential surface of the sleeve 5 of the magnet roll 2. 9 is supplied again fL, 6° Such an operation is repeatedly performed during the continuation of the developing process ○ As explained above, in the first embodiment, a In addition to providing means for detecting the amount of magnetic toner that is being restrained, a rotatable scraper is arranged between the magnetic rolls, and the magnetic toner is removed immediately before the magnetic toner on the circumferential surface of the sleeve of each magnetic roll runs out. Since the toner can be transported, the developing device has a plurality of magnetic rolls, which is larger than a developing device having at least a single magnetic roll.
It is possible to constantly supply the required minimum amount of magnetic (i, l) toner into the L imager, and to evenly distribute magnetic toner to each magnet roll, thereby preventing mechanical damage, agglomeration, moisture absorption, etc. of the magnetic toner. Next, a second embodiment of the present invention will be explained with reference to FIG. 2.
In this second embodiment, instead of the scraper 14, flenoid 16, etc. in the first embodiment, a magnetic roll 21 dedicated to toner transport consisting of a permanent magnet 19 and a sleeve 20 covering the scraper is used, and a developing magnetic roll 21 is used. , 3, except that it is the same as the first embodiment. Note that the permanent magnet 19 shown here has one N pole and one S pole magnetized. , a plurality of N 4. similar to the permanent magnet 4. There is no problem with enthusiastic discussion even if the magnet is magnetized with both the return and south poles.

The developing operation of the magnet rolls 2 and 3 related to this configuration,
The operation timing of the toner amount detection means 12 and 13 and the supply of the magnetic toner 9 by the agitator 11 are performed in the same manner and inexpensively as in the first embodiment.
The relative rotation of the magnetic toner 9 and the sleeve 20 transfers the magnetic toner 9 in the mutual direction between the magnetic rolls 2 and 3.

Moreover, in this second embodiment, the magnetic roll 2
If the magnetic toner 9 is set to be constantly driven, the amount of magnetic toner 9 between the developing magnetic rolls 2 and 3 will be evenly distributed by 2 minutes, and the distribution speed will be higher than that of the magnetic toner 9 due to development. If the amount exceeds the consumption amount, the function of the toner amount detection means 13 can be replaced by the toner amount detection means 12 (or vice versa), and the supply 9 distribution is simpler and more reliable. The function can be maintained.Although the first and second embodiments described above describe the case where there are two magnet rolls for phenomena, the present invention is not limited to this. Even if there are three or more magnetic rolls, the same function can be obtained by arranging a magnetic toner transport means, that is, a scraper or a magnetic roll dedicated to transport, between each adjacent magnetic roll. Evenly supplies the required amount of magnetic toner.

can be distributed.

As explained above, the present invention provides a developing device having a plurality of developing magnet rolls (in addition, since it is possible to constantly supply and distribute a uniform and fixed amount of magnetic toner to each magnet roll, - It is possible to carry out the developing process by supplying the minimum amount of toner required. Therefore, the rotational load on the individual magnetic rolls for development can be reduced, the magnet rolls can be driven with a small drive system, and the magnetic toner can be This has the effect that inconveniences such as mechanical damage, moisture absorption, and aggregation can be minimized, and uniform, high-quality toner images can be obtained.

[Brief explanation of drawings]

FIG. 1 is a side sectional view showing a first embodiment of a toner supply and distribution mechanism according to the present invention, and FIG. 2 is a side sectional view showing a second embodiment. 1... Recording medium 2.3... Magnet roll 4
...Permanent magnet 5...Sleeve 6, 7...Doctor blade 8...Cover 9...Magnetic toner 1
0... Toner tank 11... Agitator 12.
13...Toner amount detection means 14...Scraper
15...Fully point 16...Renoid 17...Movable piece 18...Coil spring 19...Permanent magnet 20
... Sleeve 21 ... Magnet roll patent Applicant Computer Basic Technology Research Association Representative Patent attorney Takashi Kanakura Futataki 1-

Claims (1)

[Claims] 1. A developing magnetic roll consisting of a sleeve that covers a permanent magnet with N and S poles alternately magnetized in the circumferential direction, and the permanent magnet and the sleeve rotate relative to each other. In a developing device that has a plurality of magnetic rolls and performs development by attaching magnetic toner to a latent image formed on a recording medium using the plurality of magnetic rolls, the plurality of magnetic rolls are restrained on the circumferential surface of the sleeve. A toner supply and distribution mechanism characterized in that a means for detecting the amount of magnetic toner is provided near the doctor blade facing the sleeve, and a means for arbitrarily transferring the magnetic toner is arranged between adjacent magnetic rolls. .