JPS6173169A - Developing device - Google Patents

Abstract

PURPOSE:To form a transfer mechanism required for rotation by a simple structure, to improve a picture quality, to reduce its cost, to save a space, and to simplify its maintenance by providing a coil on the periphery of a part of a developing roll, and operating directly the developing roll as a rotor part of a motor. CONSTITUTION:A developing roll 1A is constituted of a magnet roll which has contained plural opposed permanent magnets by placing alternately the S and N poles, a pair of shafts 12 for supporting both ends of the magnet roll 11 as a revolving shaft, and a cylindrical sleeve 11a fitted in the vicinity of the outside periphery of the magnet roll 11. The developing roll 1A is extended in the axial direction outside of an area required for carrying a developer of this developing roll 1A and executing development, and in its extended part, plural electrodes formed by winding a coil 13 to an iron core 14 are installed so as to be opposed to the developing roll 1A. A magnetic field controlling circuit 16 generates a revolving magnetic field in the coil group 13. In this way, the developing roll 1A is rotated electromagnetically directly, therefore, another motor as a power is not required.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a developing device for an electrostatic recording device such as a transfer type electrophotographic copying device, and the present invention relates to a developing device for an electrostatic recording device such as a transfer type electrophotographic copying device. This relates to a developing device.

[Prior art]

In an electrostatic recording device such as a transfer-type electrophotographic copying device, light from a light source such as a halogen lamp is irradiated onto the original to be copied, and the reflected light from the original is pre-banded! The image is projected onto an image forming member such as a photoreceptor drum whose surface is uniformly charged by an electrode, and an electrostatic latent image based on the original image is formed on the surface of the image forming member. This electrostatic latent image is developed by a developing device using a developer containing toner to form a visible image (toner image), and this toner image is transferred onto a transfer paper supplied from a supplying device. The transfer paper bearing this toner image is separated from the image forming member by a separating means, and after being conveyed, the toner image is thermally fused and fixed by a heat fixing device to form a permanent image on the transfer paper. The developing device in this type of electrostatic recording apparatus is, for example, shown in FIG.
a is fitted to form a developing roll. This cylindrical sleeve 1a may be fixed or rotated counterclockwise or clockwise. A doctor blade 2 for regulating the thickness of toner is held above the cylindrical sleeve 1a parallel to the cylindrical sleeve 1a with a constant gap.

Toner is stocked inside the toner supply section 3, and the necessary amount of toner is supplied to the magnetic roll 1. A photosensitive drum 4 is held at a constant interval from the cylindrical sleeve 1a, forming a developing area A. The thickness of the toner supplied from the toner replenishing section 3 is regulated by the doctor blade 2, and the toner is conveyed to the development area A while being adhered to the cylindrical sleeve la, and the latent image on the photoreceptor drum 4 is developed. here,
In order to supply toner abundantly to the developing area A, the magnet roll 1 or the magnet roll 1 and the cylindrical sleeve 1a have a diameter of about 100OR.
It rotates at a rotation speed of about PM. For this purpose, it is necessary to transmit power from a power source such as an induction motor using a belt, gears, etc. Because the rotational speed is high, noise and vibration are likely to be generated in the power transmission system, and the vibrations affect the optical system of the device, causing unevenness in the image and deteriorating the image quality. In addition, the device for transmitting power is complicated, takes up space, and is expensive.

[Problems to be solved by the invention] The present invention minimizes noise and vibration caused by the rotation of the magnet roll, and also has a simple structure for the transmission mechanism necessary for rotation, improving image quality and reducing costs. To save space,
It is an object of the present invention to provide a developing device that is easy to maintain.

[Means for solving problems]

The present invention aims to solve the above-mentioned problems.It is an object of the present invention to generate a magnetic developer by at least the rotation of the magnetic roll of a developing roll composed of a non-magnetic cylindrical body and a magnetic roll having a plurality of electrodes inside the developing roll. In the developing device configured to transport and develop, at least one set of electromagnetic coils is provided around the magnet roll outside the transport area of the magnetic developer, and the magnet roll is rotated by changing the current flowing through the electromagnetic film. This is achieved by a developing device characterized by the following.

〔Example〕

FIG. 1 shows a perspective view of a developing roll section as a first embodiment of the present invention. FIG. 2 shows the electric circuit of the coil section of FIG. 1. A plurality of opposing permanent magnets are fitted in close proximity to the outer periphery of the magnet whirl, with a magnet roll 11 having 8N poles built in alternately, and a pair of shafts 12 supporting both ends of the magnet roll 1 as rotating shafts. The developing roll IA is constituted by the cylindrical sleeve lla. The developing roll IA was extended in the axial direction beyond the area necessary for conveying and developing the developer of the developing roll IA, and a coil 13 was wound around an iron core 14 around the extended part as shown in FIG. A plurality of sets of electrodes are installed facing the developing roll IA. In the case of FIG. 1, there are two sets of four poles, but there are cases where there are four sets of eight poles. Looking at this state cross-sectionally, as shown in Figure 2, a film 13 is wound around a magnet roll 11 containing a built-in magnet.
The structure has poles facing each other.

The magnetic field control circuit 16 is a known circuit that generates a rotating magnetic field in the coil group 13. For example, if the power source 17 is a DC power source, the polarity of the coil group 13 is switched by the current collector brush and electrodes as the magnet roll 1 rotates. Alternatively, the magnetic field of the magnet roll 11 is detected by a Hall element and the polarity is electrically switched. If the power source 17 is an AC power source,
A rotating magnetic field is generated by, for example, shifting the phase of the current to the fill group. Since the developing roll IA is directly electrically rotated in this manner, there is no need for a separate motor as a power source, and there is no need for a transmission mechanism for transmitting power from the separate motor. Furthermore, since there are no rotating parts such as a transmission mechanism, there are advantages such as eliminating noise and vibration generated from the transmission mechanism.

In the present invention, since the developer transport section and the drive section corresponding to the motor are on one axis, the magnetic powder of the developer is
It is necessary to prevent l/13 from going around to the side of the iron core 14, and the magnet roll 1 corresponding to the developer conveying section is located in the developing device, and the drive section is located in the developing device with a wall member 5 in between. Must be located outside. When the cylindrical sleeve 11a rotates, it is necessary to provide a small gap between the cylindrical sleeve 11a and the wall member 5, and it is necessary to prevent toner from leaking outside through this gap.

3, 4, and 5 show the relationship between the developing roll and the wall member 5 that is effective in preventing toner from leaking to the outside.

In FIG. 3, seven non-magnetic flanges n are provided between the developer conveyance section of the non-magnetic cylindrical sleeve 21a and the motor section, and the shape is such that toner hardly passes through the gap. Fig. 4 shows an unmagnetized part 32 provided between the developer transporting part of the magnet roll 31 and the motor part, and Fig. 5 shows a notch provided between the developer transporting part of the magnet roll 41 and the motor part. Part 4
2. Both have the effect of preventing toner from leaking outside through gaps by breaking the continuity of the magnet portion.

〔Effect of the invention〕

According to the present invention, by providing a coil around a part of the developing roll and making the developing roll act directly as the rotor part of the motor, a power transmission system such as a belt, boob, gear, bear, ring, etc. is no longer necessary. The space required is also unnecessary. Costs can also be reduced. In addition, noise and vibration generated from the transmission system are reduced, and copy image quality is improved.

Since the power is directly connected, a developing device has been provided that has many effects such as a reduction in the torque loss of the power.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of a developing roll section according to an embodiment of the present invention. FIG. 2 is an electrical circuit diagram of the coil section shown in FIG. 1. 3, 4, and 5 show various cross-sectional views of the developing roll portion according to the present invention. FIG. 6 shows a sectional view of a conventional developing device. IA...Developing rolls 11, 21, 31, 41...Magnetic rolls 11a, 21a, 31, 41a...Cylindrical sleeve...Shaft 13...
Coil 14... Iron core 16... Capacitor 17... Power supply ρ...7
Lunge 32...Unmagnetized part 42...
・Incision Department Agent Patent Attorney No 1) Parent-in-law Figure 1 Figure 3 t 1a

Claims (1)

[Claims] In a developing device configured to transport and develop a magnetic developer by at least the rotation of a developing roll comprising a non-magnetic cylindrical body and a magnetic roll having a plurality of magnetic poles therein, the magnetic developer is At least one set of electromagnetic coils is provided around the magnet roll outside the conveyance area,
A developing device characterized in that the magnet roll is rotated by changing the current flowing through the electromagnetic coil.