JPH0588545A - Toner supplying device - Google Patents

Abstract

PURPOSE:To enhance the dispersibility of a toner supplied from a toner supplying device to a developing device by forming an electrifying coat film for electrifying a toner by friction of the toner on the surface of a toner supplying roller. CONSTITUTION:The electrifying coat film 3 for electrifying the toner by the friction with the toner is formed on the surface of the toner supplying roller 2 for discharging the toner from a toper hopper 1. The electrifying coat film 3 is formed of a fluororesin and the film thickness thereof is 10 to 20mum. Then, the electrifying coat film 3 and the toner rub against each other and the toner is electrified at the time of supplying the toner (during the rotation of the toner supplying roller 2). The particles of the toner electrified to the polarity reverse from the polarity of the electrifying coat film 3 are then repulsed by each other and are more easily dispersed. The toner is uniformly electrified in such a manner, by which the electrostatic dynamical repulsion force acts among the toner particles and the dispersibility of the toner is enhanced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a toner supply device.

[0002]

2. Description of the Related Art As shown in FIG. 3, an electrophotographic image forming apparatus such as an electrophotographic printer or an electrophotographic copying machine is
The photoconductor 10 is rotated in one direction, the surface thereof is uniformly charged by a charger 11, and a light beam 12 such as a laser beam is irradiated at an exposure portion to form an electrostatic latent image corresponding to image data. In the developing unit, toner is electrostatically attracted to the electrostatic latent image from the developing unit 13 to form a toner image on the surface of the photoconductor 10, and in the transfer unit, the transfer unit 14 transfers the toner image onto paper, and the peeling unit 15 The sheet separated from the photoconductor 10 is conveyed to the fixing unit by the conveying belt 16, and the fixing unit 17 fixes the toner image on the sheet in the fixing unit.

Since toner is supplied to the developing device 13 in accordance with the consumed toner, as shown in FIG.
A toner concentration sensor 18 for detecting the toner concentration in
A toner supply device 19 is attached.

The toner supply device 19 includes a toner hopper 20.
And a toner supply roller 21 that controls the amount of toner supplied from the toner hopper 20 to the developing device 13, and when the toner concentration detected by the toner concentration sensor 18 falls below a predetermined value, the toner supply roller 21 rotates to a constant amount. Toner is dropped and supplied into the developing device 13.

The toner supplied from the toner supply device 19 into the developing device 13 is stirred in the developing device 13 by the stirring paddles 22 and 2.
3 is mixed with magnetic particles called a carrier to form a developer, adheres to the mag roller 24, and is carried out from the developing device 13 to the developing section.

[0006]

By the way, according to the conventional toner supply device 19, the toner is supplied to the developing device 13 in an agglomerated state, so that the fluidity of the developer is lowered and the toner density control is disturbed. is there. In addition, the agglomerated toner may not be well stirred with the carrier, may be carried to the developing unit in the agglomerated state, and may be transferred to the sheet through the photoconductor 10, so-called raw toner rising may occur.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a toner supply device capable of improving the dispersibility of the toner supplied from the toner supply device to the developing device. ..

[0008]

In order to achieve the above-mentioned object, the toner supply device of the present invention, as shown in FIG. 1, for example, supplies toner to the surface of a toner supply roller 2 which discharges toner from a toner hopper 1. It is characterized in that the charging coat film 3 for charging the toner by the friction is formed.

[0009]

In the present invention, since the charge coat film 3 is formed on the surface of the toner supply roller 2, the charge coat film 3 and the toner rub against each other when the toner is supplied (when the toner supply roller 2 is rotated). The toner is charged, and the particles of the toner charged to the opposite polarity to the charge coat film 3 repel each other and are easily dispersed.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A toner supply device according to an embodiment of the present invention will be specifically described below with reference to FIGS.

FIG. 1 is a principle view of the present invention, in which toner particles are schematically shown by black dots. Further, this toner supply device includes a toner hopper 1 and a toner hopper 1
And a toner supply roller 2 for discharging toner from the developing device to the developing device.

The toner supply roller 2 is made of iron, stainless steel,
It can be made of aluminum alloy, synthetic resin, etc.,
Here, it is formed of the same solid aluminum alloy rod material as that of the conventional toner supply roller 2, and a plurality of (6 in this case) concave grooves 4 are provided at appropriate intervals on the outer peripheral surface.
The thickness of the toner supply roller 2 is 10 to 2 on the surface.
A charge coat film 3 having a thickness of 0 μm is formed.

The charge coat film 3 may be any as long as it can charge the toner by friction with the toner, for example, fluororesin, acrylic resin, styrene-acryl copolymer resin, silicone resin, polyester resin, polybutadiene resin and the like. Can be used. In this embodiment, the charge coat film 3 is formed of fluororesin.

As a method of forming the charge coat film 3 on the surface of the toner supply roller 2, for example, the charge coat film 3 is dissolved in an organic solvent and the solution is added to the toner supply roller 2.
Is applied (immersing method), or the solution is sprayed onto the toner supply roller 2 (spraying method) to be attached to the surface of the toner supply roller 2 and dried or heat-cured.

The thickness of the charge coat film 3 is determined in consideration of the chargeability imparting ability and durability of the charge coat film 3. In the case of the charge coat film 3 formed of a fluororesin, as shown in FIG. 2, when the film thickness is less than 10 μm, the charge imparting ability becomes sufficiently high, but the durability period becomes remarkably short, which is not preferable. .. On the other hand, if the film thickness exceeds 20 μm, the durability period becomes sufficiently long, but the charge imparting ability is significantly reduced, which is not preferable.

A toner supply port 5 closed by the toner supply roller 2 is opened on the lower surface of the toner hopper 1, and an edge 6 in the lower rotation direction of the toner supply roller 2 is formed in the lower part of the toner supply roller 2. The toner is scraped from the peripheral surface of the toner supply roller 2 by elastically contacting the peripheral surface.

In this toner supply device, when the toner supply roller 2 is rotated, the charge coat film 3 on the surface of the toner supply roller 2 rubs against the toner, and the charge coat film 3 is negatively charged and the toner is positively charged. .. That is, when the charged state of the toner was measured for the toner dropped and supplied from this toner supply device and the toner dropped and supplied from the conventional toner supply device, it was not charged in the conventional example as compared with the above-mentioned one. In the example, it can be confirmed that 2 to 5 μC / g is charged.

By thus uniformly charging the toner, electrostatic repulsion acts between the particles of the toner, and the dispersibility of the toner is enhanced. For example, when the toner dispersion state of the toner dropped and supplied from the toner supply device and the toner dropped and supplied from the conventional toner supply device was visually observed, in the conventional example, the toner dispersion state was poor and aggregation was observed. On the other hand, in the above-mentioned one example, it was observed that the toner was in a good dispersion state with almost no aggregation, and it was found that the dispersibility of the toner was enhanced.

Further, the average particle diameter of the toner of the toner dropped and supplied from the toner supply device and the toner dropped and supplied from the conventional toner supply device was observed with a microscope, and it was 50 to 100 μm in the conventional example. On the other hand, in the above example, it is observed that the thickness is about 16 to 20 μm, which shows that the dispersibility of the toner is enhanced.

By increasing the dispersibility of the toner as described above, the aggregation of the toner is less likely to occur, the aggregation toner is prevented from being carried to the developing section, that is, the occurrence of so-called raw toner rising is prevented, and the printing quality is improved. Be done. Further, since the dispersibility of the toner is increased, the fluidity of the toner is increased, and the toner concentration can be controlled accurately and stably.

[0021]

As described above, according to the present invention, the toner is charged by friction with the charge coat film, and electrostatic repulsion is imparted between the toner particles to improve the dispersibility of the toner. Can be increased.

Further, as a result, the aggregation of toner and the rise of raw toner can be prevented, the printing characteristics can be enhanced, the fluidity of the toner can be enhanced, and accurate toner density control can be stably performed. Become.

[Brief description of drawings]

FIG. 1 is a principle diagram of the present invention.

FIG. 2 is a characteristic diagram of a fluororesin charge coating film.

FIG. 3 is a principle diagram of an electrophotographic image forming apparatus.

FIG. 4 is a cross-sectional view of a developing device and a toner supply device.

[Explanation of symbols]

 1 Toner hopper 2 Toner supply roller 3 Charge coating film

Claims (2)

[Claims] 1. A toner supply device characterized in that a charge coat film (3) for charging the toner by friction with the toner is formed on the surface of a toner supply roller (2) for discharging the toner from the toner hopper (1). .. 2. The toner supply device according to claim 1, wherein the charging coat film (3) is made of a fluororesin and has a film thickness of 10 to 20 μm.