JPS6211156A - Method for measuring deterioration degree of developer for electrophotography - Google Patents

Abstract

PURPOSE:To measure the deterioration degree of a developer, by scraping off the toner developed on a metal roller by using a blade and recovering the same under a vacuum sucking condition to measure the area resistance of a carrier. CONSTITUTION:A metal drum 1 is connected to a developing power source 2 to apply potential to a developing device 3. The toner 5 supplied from the outside is supplied to a magnetic roller 4 by a feed mechanism 6 and charged while rotated under the friction with a carrier to be electrostatically attracted to the drum 1. A blade 7 scrapes off the toner 5 on the drum 1 to a dust collector 8 to recover the toner 5. The area resistance of the carrier increases with the increase in the time of stirring by the magnetic roller 4.

Description

[Detailed Description of the Invention] [Summary] Instead of using an actual machine to test the lifespan of the developer, this method uses a metal drum to cause the developer to change over time, and thereby determines the state of deterioration.

[Industrial application field]

The present invention relates to an economical method for measuring the degree of deterioration of an electrophotographic developer.

Electrophotographic technology is widely used in copying machines, but is also actively used in information devices such as printers and facsimile machines.

The printing process of an electrophotographic printer involves uniformly charging the surface of a photoconductor drum coated with a photoconductive insulator using corona discharge, and then emitting light that is turned on and off in response to electrical signals. A conductive insulator is irradiated to create an electrostatic latent image, and toner is attached to this latent image to form a visible image.

Here, the toner is colored fine particles with a particle size of 5 to 30 μm made by dispersing a colorant in a synthetic resin, and the developer is formed together with a magnetic powder called Kya I77 with a particle size of 30 to 300 μm. The developer is supplied to a magnetic roller, and the carrier is magnetically attracted to form a magnetic brush. During the rotation, the carrier and toner rub against each other and become electrically charged. The toner carried by the carrier to the latent image is Electrostatic forces cause it to adhere to the latent image and form a visible image.

Next, the toner image created in this way is electrostatically transferred onto the recording paper by applying an electric field from the back side of the recording paper in the transfer section, and then heat and pressure are applied to the toner image in the fixing device. The recording is completed by fusing it to the recording paper.

Here, the carrier and toner supplied to the magnetic roller rotate while rubbing against each other due to the rotation of the magnetic roller, and the characteristics deteriorate in proportion to the number of printed sheets.

The present invention relates to a method for measuring the state of deterioration of a developer.

[Conventional technology]

The deterioration of the developer is due to a phenomenon called toner filming, which is a stage in which the toner and the carrier magnetically attracted to the magnetic roller rotate while rubbing against each other.
This is because toner called spent toner, which does not contribute to development, fuses to the surface of the carrier, reducing the triboelectric charging function.

In printing, such deterioration of the developer is caused by ■optical density (O
Decrease in optical density (abbreviated as 00), ■
It is observed as a fog (stain) on the white background (background area).

Therefore, when the developer deteriorates, it is necessary to replace it with a new one, but until now, the method of evaluating the deterioration characteristics of the developer has been to print with an actual machine using printing paper and evaluate it.

However, this method has the problem that not only the cost of printing paper required for long-time running tests is enormous, but also a large amount of labor costs are required.

Therefore, attempts have been made to place carrier and toner in a developing device and rotate a magnetic roller, thereby determining the state of deterioration of the developer. There was a problem that I couldn't get it.

[Problem that the invention seeks to solve]

As mentioned above, in electrophotographic equipment, as the number of sheets printed increases, the OD decreases and fogging occurs, and the developer deteriorates. However, when this deterioration characteristic is evaluated using an actual machine, paper costs and labor costs are reduced. Since the scale is enormous, the challenge is to find an alternative evaluation method.

[Means for solving problems]

The above problem can be solved by connecting the metal drum to a development power source, repeatedly using a blade to scrape off and collect the toner of the developer that has been electrostatically attracted to the metal drum from the magnetic roller, and then forming the developer. This problem can be solved by using a method for measuring the degree of deterioration of an electrophotographic developer, which is characterized by measuring the sheet resistance of the carrier.

[Effect]

In the present invention, instead of printing on paper using an actual machine, the toner developed on a metal roller is scraped off using a blade, and the toner is collected by vacuum suction, which is repeated. The degree of deterioration of the developer is measured by measuring the resistance.

This saves paper usage.

〔Example〕

FIG. 1 is a block diagram of a deterioration degree measuring mechanism according to the present invention, FIG. 2 is a deterioration characteristic of a developer obtained using an actual machine, and FIG. 3 is a deterioration characteristic of a developer determined by the mechanism shown in FIG.

That is, in FIG. 1, a metal drum 1 is made of aluminum (At) metal, for example, and is not coated with a photoconductive insulator as in the prior art.

A potential is applied to the developing device 3 by the developing power source 2.

Here, the developing device 3 has a magnetic roller 4 which is rotated by a motor while magnetically adsorbing the carrier on its surface, and the toner 5 supplied from the outside is supplied to the magnetic roller 4 by a conveyance mechanism 6 and is rubbed against the carrier. By adjusting the gap between the developing device 3 and the metal drum 1, the toner 5 is electrostatically attracted to the metal drum 1 having a potential of the opposite sign.

Next, on the side of the metal drum 1, there is a blade 7 for scraping off toner made of hard rubber such as urethane rubber, and a dust collector 8.
The toner 5 electrostatically adsorbed on the metal drum 1 is scraped off by a blade 7 and collected by a dust collector 8.

By employing such a mechanism, the present invention allows a toner filming phenomenon equivalent to this to occur without using printing paper.

Figure 2 shows the deterioration characteristics of developer using a conventional actual machine.
As the number of printed sheets increases, the sheet resistance value of the carrier decreases from the initial value of 1.
Figure 3 shows the deterioration characteristics of the developer measured using the mechanism shown in Figure 1 according to the present invention. As the stirring time by the magnetic roller 4 increases, the sheet resistance changes in a similar manner.
It has increased to the value of m.

As described above, by implementing the present invention, it is possible to measure the deterioration state of the developer without using paper.

〔Effect of the invention〕

As described above, conventionally, measuring the deterioration characteristics of developer required a large amount of paper and manpower to replace the paper, but with the implementation of the present invention, the deterioration characteristics can be evaluated with the same accuracy without using any paper. becomes possible.

[Brief explanation of drawings]

FIG. 1 is a block diagram of the deterioration degree measuring mechanism, FIG. 2 is the deterioration characteristics of the developer measured by an actual machine, and FIG. 3 is the deterioration characteristics of the developer determined by the mechanism shown in FIG. In the figure, l is a metal drum, 2 is a developing power source, 3 is a developing device,
4 is a magnetic roller, 5 is a toner,
6 is a conveyance mechanism, 7 is a blade, and 8 is a dust collector. /′

Claims (1)

[Claims] Connect the metal drum (1) to the development power source (2), and use the blade (7) to scrape off the developer toner (5) that has been electrostatically attracted to the metal drum (1) from the magnetic roller (4). 1. A method for measuring the degree of deterioration of an electrophotographic developer, comprising repeatedly performing a collecting operation and then measuring the sheet resistance of a carrier constituting the developer.