JPS5942567A - Developing device of picture formation device - Google Patents

Abstract

PURPOSE:To improve picture density even at low humidity and to prevent the thinning and unevenness of lines, by providing a humidifier in a toner container and holding the inside of the container above specific humidity, and preventing a developer from becoming dry and increasing resistance. CONSTITUTION:In a developing contaner 9, a toner chamber 11 for storing toner 1 and a water chamber 12 for reserving water 5 are partitioned by a center wall 13. The water 5 is used to humidify the toner 1 and vaporized water passes through an air hole 7 provided in the center wall 13 and is guided into the toner chamber 11 of the developing container 9 to humidify the toner 1. When water is supplemented, the water level is checked on the liquid amount meter 6 formed by attaching an indication bar 6b to a float 6 on the surface of the water 5 and the water is supplied and injected from an injection opening 8.

Description

[Detailed description of the invention] related.

Various methods are known or proposed for developing devices that use a one-component developer.

Among these, the jumping development method is known as unique. In this method, a one-component developer is uniformly applied as a thin layer onto a developer holding means, and then the developer holding means and the latent image holding means are opposed to each other with a small gap being maintained. Then, the electrostatic attraction of the latent image causes the developer to fly from the developer holding means onto the electrostatic latent image holding means to perform development. (Refer to Japanese Patent Publication No. Sho Q./-94'?j, U.S. Patent No. 2t3'y, D00) According to this method, not only the developer is not attracted to the non-image area where there is no latent image, but also the developer Since the toner does not come into contact with non-image areas, good development without any fogging is achieved. Furthermore, since carrier particles are not used, there is no fluctuation in the mixing ratio of the developer and there is no deterioration of the carrier particles. Good effects can be obtained.

The applicant has also proposed a developing method different from this jumping developing method, as described in Japanese Patent Application Laid-Open No. 2003-120001 and II-4'. ? No. 037 and JP-A-S
s-igt. He proposed a completely new developing method as described in issue zz.

In the former development method, a one-component magnetic developer, a developer holding means (non-magnetic), and a magnetic field generating means are arranged at 110, and a uniform thin layer of developer is formed on the developer holding means by the magnetic force of the magnetic field generating means. The structure is such that the latent image holding means are placed opposite each other with a minute gap formed so that the surface layer of this thin developer layer does not come into contact with the surface on which the electrostatic latent image is formed. Development is performed by elongating the developer facing the image area due to the electrostatic attraction of the image. Also, since development is performed without contacting the non-image area with the developer, a developed image with no IJ blurring is produced. can get.

The latter developing method has the same configuration as the former, but the latent image is
, Apply a developing bias to the holding means as an AC bias (a combination of DC heavy duty and AC voltage may be used), and further reduce the gap between the electrostatic latent image holding means and the developer holding means. Development is performed by changing the color over time.In this case, in the early stage of development, the halftone area is developed by allowing the developer to reach the non-image area of the D latent image. Development is carried out so as to reach only the target image area.As a result, compared to the former developing method, development is achieved with better halftone reproducibility and fog-free development.

In this way, the development method in which a thin layer of component developers is arranged opposite to the latent image surface has extremely superior effects in terms of development performance, image reproducibility, developer equivalence, etc. compared to conventional methods. can get.

However, in the above-mentioned developing device configuration, the developer becomes electrically charged due to friction with the developer holding means, so if this is used in a humid environment of several inches, the developer becomes more resistant and is formed on the developer holding means. In the thin layer of developer, only the lower layer developer that is in contact with the developer holding means is triboelectrically charged and strongly adsorbed or fixed on the developer holding means by the mirror force. The thin upper layer toner has less opportunity to be triboelectrically charged, and the developing ability of the developer as a whole decreases.

An image using this will have a low density and thin lines. Further, if this state continues for a long period of time, the lower layer developer becomes abnormally charged and the toner cannot be made to stand up by the magnetic force of the magnetic field generating means, resulting in unevenness on the developer holding means.

In view of the above-mentioned drawbacks of a developing device using a one-component developer, it is an object of the present invention to provide a developing device that provides good image density even in low humidity, has no line thinning, and does not cause burrs.

In order to prevent the developer from drying out and becoming highly resistive when exposed to a low-humidity environment, the inside of the toner container is always maintained at a constant level.
- Keep it at the opening degree.・Is it added to the Utona container? ! i? It is characterized by having a container installed.

Hereinafter, the present invention will be specifically described in detail with reference to Examples.

FIG. 1 is a schematic diagram of the developing device of the present invention.

/ is a one-component magnetic developer (hereinafter abbreviated as l-ner), ``g'' is a magnetic blade that forms a thin layer, ``3'' is a developing sleeve that holds the toner, and ``g'' is a magnet that generates a magnetic field. The developer container 9 is partitioned by a partition wall /3 so as to form a toner chamber // that stores toner / and a water chamber / 7 that stores water.

Water 5 humidifies the toner, so the evaporated water is the partition wall/3
The toner chamber of the developer container passes through the ventilation hole 7 provided in the
/ to humidify the toner /. Water is replenished using a liquid M meter 6, which has an indicator rod 6b attached to a float 6a placed on the surface of the water S.
This is done from the injection port g by checking the water level.

Figure 2 shows the case where water is directly poured into the water chamber 12 in Figure 1.
In order to prevent water from leaking into the toner chamber due to machine vibrations, etc., the ice chamber 7.2 was filled with water absorbed by a grafted starch water absorbing member ja instead of water. be. The superabsorbent polymer water absorbing member &a used here has a water absorption rate of 100 to /θ00, and when it absorbs water, its volume increases by 10θ to 10θO times. Therefore, the upper surface of the water absorbing member ta falls within the ice chamber 7.2 due to evaporation of water, so the amount of water in the water chamber 2 can be determined by the liquid level gauge 6. Since these water absorbing members, ta, exhibit water volatility close to that of free water, the same effect as the water used in FIG. 1 was obtained.

Solid line A in FIG. 3 shows the relationship between the external environmental humidity (horizontal axis) and the internal humidity (vertical axis) of the developing device when the developing device is installed in a copying machine and the temperature is θ°C. . Arch line B is a conventional example. It can be seen that even in an extremely low humidity environment, the inside of the developing device maintains a humidity of several tens of degrees, indicating a large humidifying effect.

Curves C and D in Figure 1 are the external environmental humidity (horizontal axis) and image density (vertical axis) when an image is produced at each external humidity using a developing device in which the present invention is implemented on a conventional developing device. Show the relationship between -. C
D is the case where only the conventional developing device is used, and D is the case where the present invention is additionally used in the conventional developing device. It can be seen that in the conventional example, the concentration decreases significantly in a low humidity environment, whereas in the example to which the present invention is applied, this decrease is alleviated. Of course, we did not order unevenness even for long-term use. The temperature is 20℃ again! When the present invention was applied to a conventional developing device in which unevenness occurred at an external humidity of r%, the humidity inside the developing device became 3θ and the developing unevenness disappeared after 30 minutes. At this time, the image v1°i degree was arranged from o, q to /, /. On the other hand, at an environmental temperature λθ° C. and a humidity gθ˜90°, the humidity caused by the humidifying member was small, and the addition of the front groove member did not have any adverse effect on the toner.

As described above, according to the present invention, by providing a humidifying member in the developing container, it is possible to obtain uniform copies in a low-humidity environment without a decrease in hardness, without narrowing of lines, and in a long-term stable manner.

[Brief explanation of drawings]

FIG. 1 is a longitudinal cross-sectional view of an embodiment of the present invention, FIG. 2 is a longitudinal cross-sectional view of another embodiment of the present invention, and FIG. 3 is a diagram showing environmental humidity and the inside of the developing device in the embodiment of the present invention and the conventional example. Diagram showing the relationship between humidity. FIG. 1 is a diagram showing the relationship between environmental humidity and image density in the embodiment of the present invention and the conventional example. ri...Water, ta...Water absorption member 6...Liquid level meter 7...Vent hole g...Inlet 1, Patent applicant Canon Co., Ltd. Agent Arai - Department 1 Figure 2) 0 3 figure

Claims (1)

[Claims] / In a developing device that visualizes a latent image by arranging a latent image holding member and a developer holding member holding a one-component developer with a uniform thickness to face each other with a gap, the developer holding member is Developing device 1' of an image forming apparatus characterized in that a toner storage container for supplying component developers is equipped with a humidifier for the toner in the container.
7.