JPS6217231B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an apparatus for supplying magnetic toner to a developing section of a dry electrostatic copying machine.

Dry electrostatic copying machines are classified into direct type and transfer type. The former makes copy paper photosensitive and forms an electrostatic latent image directly on it, which is then developed with powdered toner, whereas the latter forms an electrostatic latent image on a photosensitive drum surface. This is then developed with powdered toner and then transferred onto non-photosensitive copy paper. In any case, there is a development process in which toner is attracted to the electrostatic latent image to form a developed image.
For example, in the case of a transfer type, toner is supplied to a developing roller facing a drum-shaped photoreceptor, and by rotating the drum, the developing roller adsorbs the toner to the entire surface of the photoreceptor. . In this case, the amount of toner adsorbed onto the photoreceptor must be constantly supplied to the developing roller.
In order to supply toner by gravity, an elongated toner bath is provided above the developing roller, and the toner is allowed to fall from there over the entire length of the developing roller. However, since this toner bath occupies a large volume,
This is a major hindrance to the overall layout of the copying machine. In order to improve this point, various methods have been proposed in which a toner bath is placed below the developing roller and toner is supplied to the developing roller by mechanical means. It is difficult to supply toner uniformly.
Furthermore, to replenish the toner bath with toner, it must be pulled out of the machine, which is more cumbersome to operate than in wet development.

Furthermore, as shown in Japanese Patent Application Laid-Open No. 50-129040, it is known that the developer is conveyed to the duct by disposing a magnetic roller in the duct. Moreover, since the magnetic roller is rotated within the duct, the toner tends to aggregate and clog, and the toner on the magnetic roller cannot be used until the end, which is uneconomical. There was a problem in that it was troublesome to remove the toner adhering to the magnetic roller.

The present invention aims to solve the above-mentioned problems, and provides a duct disposed above and along the developing roller, a hopper communicating with one end of the duct, and an outside of the duct. and generating a magnetic field across the duct;
and a magnet that moves the magnetic toner in the hopper along the duct, and the magnet moves the magnetic toner in the hopper by its attractive force and supplies it into the duct. The apparatus is characterized in that it has a roller having grooves formed on its circumferential surface in the axial direction, and the rotation of the roller causes the magnetic toner to fall to the developing section.

Next, each embodiment of the present invention shown in the accompanying drawings will be described in detail.

1 to 3 show a first embodiment of the present invention. A hopper 1 is disposed above the end of the developing roller 3 and stores magnetic toner 6. The top of the hopper 1 is open, and toner 6 can be easily replenished into the hopper 1 by opening a door (not shown) on the side of the copying machine. In addition, if necessary,
A duct extending from the toner supply port to the hopper 1 may be provided to supply the toner 6.
The bottom of the hopper 1 is formed into a funnel shape, and the duct 4
is connected to. The duct 4 is arranged above and along the developing roller 3, and only the bottom surface facing the developing roller 3 is open. This bottom surface is closed by rollers 5. The roller 5 has a plurality of axial grooves 9 arranged at equal intervals on its circumferential surface. The duct 4 is made of a non-magnetic material, and magnets 2 and 2' are arranged on both sides thereof.
The magnets 2 and 2' are arranged in a direction across the duct 4, with different polarities facing the duct 4. The magnets 2 and 2' are attached to pulleys 8a and 8a as shown in FIG.
It is attached to the endless conveyor wires 7, 7' wrapped around the conveyor wires 7, 8b, 8a', 8b'.
7', it runs along the duct 4 as shown by arrows A, A'. That is, the magnets 2 and 2' are
With its magnetic pole facing the duct 4, the hopper 1
It starts from the lower part of the duct 4, reaches the other end of the duct 4, leaves the duct 4, turns back to the hopper 1, approaches the duct again, and runs along the duct 4. Note that it is preferable to provide not only one set of magnets 2 and 2' but a plurality of sets.

Next, the operation of the device will be explained.

When the copying machine is started, the developing roller 3 starts rotating. The number of rotations or the number of sheets of developing roller 3 is counted, and when it is detected that a predetermined amount of toner has been consumed, the roller 5 and the conveyor wires 7, 7' are driven, and the magnets 2, 2' run in the direction of arrow A. do. The magnets 2 and 2' attract magnetic toner 6 through the side wall of the duct 4.
The attracted toner 6 is attracted to the magnet 2,
2' moves within the duct 4 towards its end. When the magnets 2 and 2' reach the end of the duct 4, the magnets 2 and 2' separate from the duct 4, and the toner 6, together with the fact that the end of the duct 4 is closed, is oxidized there. The toner 6 that is sent one after another in this way accumulates in the duct 4 and fills the entire length of the duct 4 starting from the closed end. On the other hand, as the roller 5 rotates, the toner 6 in the duct 4 falls toward the developing roller 3 due to the action of the groove 9, and the toner 6 is supplied to the developing roller 3. The developing roller 3 supplies toner 6 to the photosensitive drum 12 to perform development. The toner 6 in the hopper 1 is supplied to the end of the duct 4 by its own weight, and is replenished into the duct 4 by the magnets 2, 2', so that the duct 4 is always filled with toner 6. Therefore, the toner 6 is always uniformly supplied to the developing roller 3 over its entire length.

A tray 10 is provided below the developing roller 3, and stores the excess toner 6 scraped off by the doctor 11. This toner 6 is returned to the hopper 1 again via a route not shown. Third
Instead of the magnets 2 and 2' shown in the figure, a plurality of electromagnets are arranged at equal intervals along one side wall of the duct 4, and a long and narrow magnetic plate is arranged close to the other wall, and a current is applied to the electromagnets. The magnetic field is sequentially magnetized along the duct 4 to move the magnetic field. The magnetic toner inside the duct 4 can be configured to be transported by the movement of this magnetic field. The operation timing for conveying the magnetic toner by this electromagnet may be the same as that described above.

4 to 6 show a second embodiment of the present invention. In this example, a magnet roll 13 and a magnetic plate 14 are arranged along the duct 4 instead of the magnets 2, 2'.
The magnet roll 13, as shown in FIG.
It has spiral magnetic poles N and S on its circumferential surface, is arranged along the side wall of the duct 4, and is rotated as shown by arrow B. The magnetic plate 14 faces the magnet roll 13 via the duct 4, but the side wall of the duct 4 on the side opposite to the magnet roll 13 itself may be composed of the magnetic plate 14.

The magnetic field generated by the magnet roll 13 crosses the duct 4 and forms a loop through the magnetic path formed by the magnetic plate 14, so that the magnetic toner 6 interacts with the magnetic poles N and S of the magnet roll 13. It is attracted to the opposite portion of the plate 14. As the magnet roll 13 rotates in the direction of arrow B, this magnetic field moves in the direction of arrow C, that is, from the hopper 1 to the closed end of the duct 4, so that the toner 6 attracted by it moves in the direction of arrow C. The liquid also moves in the same direction and fills the duct 4 as in the previous embodiment.

In the present invention, the toner 6 in the duct 4 is compressed to some extent toward the closed end of the duct 4, but this force is applied by the attraction force of the magnets 2, 2' or the magnet roll 13. Therefore, the toner 6 does not condense due to this compression. Also, if the magnets 2, 2' and the magnet roll 13 are not activated all the time, but are activated when the roller 5 rotates, the consumed toner will be supplied into the duct, thereby preventing the toner from being compressed. do not have.

The present invention includes a duct disposed above and along the developing roller, a hopper communicating with one end of the duct, and a hopper disposed outside the duct to generate a magnetic field that crosses the duct and to transmit the magnetic field to the duct. The magnet moves the magnetic toner in the hopper by its attractive force and supplies it into the duct. It has a roller with grooves formed in the direction, and the rotation of the roller causes the magnetic toner to fall to the developing area. (1) There is no need to place it in a duct (conveyance path); There is no longer a restriction that the path size must be set larger than the size of the Hiku magnet →
It becomes possible to form a thin duct.

(2) Rotating and rotating objects are usually installed in a narrow frame.
The level of difficulty in designing and achieving functionality is very different between placing moving objects and being able to freely place them outside of the frame in a large space.

(3) Since the magnet is rotated within the frame, the toner tends to aggregate and become unable to be transported (clogged easily). cannot be used and is uneconomical (5) It is difficult to remove toner stuck to the magnet if it is placed inside during maintenance. If it is attached externally, it has the effect that it does not stick to magnets and is easy to maintain.

[Brief explanation of the drawing]

1 to 3 show a first embodiment of the present invention, in which FIG. 1 is a side view, FIG. 2 is a front view, and FIG. 3 is a plan view. Figures 4 to 6
The figure shows the second embodiment, and FIG. 4 is a side view thereof.
FIG. 5 is a front view, and FIG. 6 is an enlarged view of the magnet roll. 1... Hopper, 2, 2'... Magnet, 3... Developing roller, 4... Duct, 5... Roller, 6
...Magnetic toner, 7,7'...Transport wire, 1
3... Magnet Troll.

Claims (1)

[Claims] 1. A duct disposed above and along the developing roller, a hopper communicating with one end of the duct, and a hopper disposed outside the duct to generate a magnetic field across the duct and transmit it along the duct. and a magnet that is moved by
The suction force moves the magnetic toner in the hopper and supplies it into the duct, and the duct has a roller with a groove formed in the axial direction of the circumferential surface in an opening provided at the bottom of the duct. A magnetic toner supply device for a dry electrostatic copying machine, characterized in that magnetic toner is dropped into a developing section by rotation of a roller.