JPH035577B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a fur brush developing method for developing an electrostatic latent image formed on the surface of a photoreceptor of an electronic copying machine.

One of the developing devices for electronic copying machines currently in practical use is one that uses a magnetic brush. This uses a magnetic two-component or magnetic one-component method in which a magnetic brush is brought into sliding contact with a photoreceptor, which is an image carrier, and supplies toner or magnetic toner to an electrostatic latent image formed on the surface of the photoreceptor. There is.

However, the magnetic roller that forms the magnetic brush is expensive and requires a high degree of mechanical precision, and in the magnetic two-component method, the carrier itself has a limited lifespan, making it difficult to maintain a constant mixing ratio of the carrier and toner. There are drawbacks such as difficulty in maintaining the stability of the machine, and a lot of time and effort is required to maintain the stability of the machine.

Furthermore, recently, a fur brush development method using a fur brush roller has been proposed, but since the developer used here is a non-magnetic toner that does not use a carrier, the toner is uniformly charged and background fog in the image is prevented. It is necessary to do so. However, although a bias voltage is conventionally applied to the fur brush roller to charge the toner, there is variation in the amount of toner charge, and background fogging of images due to uncharged toner is unavoidable.

This invention was made in view of the above-mentioned circumstances, and its purpose is to reduce background fog in images by tribocharging toner and developing the toner with a charge amount in the range of 5 to 25 μc/gr. prevent,
The present invention aims to provide a fur brush developing method that can obtain stable image density.

The present invention will be explained below based on an embodiment shown in the drawings. In FIG. 1, reference numeral 1 denotes an image carrier, such as a photoreceptor, of a dry type electronic copying machine, which is designed to rotate in the direction of the arrow. A developing device 2 is provided adjacent to the photoreceptor 1 . The developing device 2 includes a toner storage box 3, a toner supply roller 4 provided in the toner storage box 3, a charging roller 5 that contacts the toner supply roller 4, and a charging roller 5 that contacts the photoreceptor 1. It consists of a developing fur brush roller 6 that comes into sliding contact with the surface. The toner storage box 3 contains a non-magnetic toner 7 made of nigrosine dye and an amino group-containing resin. Further, the toner supply roller 4 and the charging roller 5 rotate in the direction of the arrow, and bristles 4a..., 5a... are implanted on their surfaces, and the bristles 4a and 5a rub against each other while maintaining a predetermined contact width. It's becoming like that. Further, the developing fur brush roller 6 is formed by providing a urethane layer 9 on the outer peripheral surface of the mandrel 8, and implanting short bristles 11 on the outer peripheral surface of the urethane layer 9 via a conductive adhesive layer 10. It has been this hair body 1
1 is made of rayon fiber with a specific resistance of 10 ⁶ to 10 ¹⁴ Ωcm, a length of 1.5 mm, and a thickness of 1.5 denier, and the surface density is
It is formed at 20,000 lines/cm ² .

Next, the operation of the above embodiment will be explained.
When the electrostatic latent image formed on the surface of the photoreceptor 1 faces the developing device 2 as the photoreceptor 1 rotates, a developing fur brush roller 6 rotating in the direction of the arrow causes the electrostatic latent image to be formed on the surface of the photoreceptor 1. Magnetic toner 7 is supplied and the electrostatic latent image is developed. At this time, the non-magnetic toner 7 in the toner storage box 3 is transferred to the toner supply roller 4.
The bristles 5a of the charging roller 5 rub against the bristles 4a of the toner supply roller 4 and the bristles 11 of the developing fur brush roller 6 via the charging roller 5. Therefore, the non-magnetic toner 7 being transported is triboelectrically charged. Moreover, the toner charge amount is determined by the number of rotations of the charging roller 5, the bristles 4a of the bristles 5a, and the bristles 1 of the bristles 5a.
It can be arbitrarily set by adjusting the contact width and toner concentration with respect to 1. That is, in order to measure the toner charge amount of the non-magnetic toner 7 adhering to the bristles 11 of the developing fur brush roller 6, a cyclone charge amount measuring device is used as shown in FIGS. 2 and 3. This measuring device has a connecting tube 14 connected to a vacuum suction device 13 at the upper end of a metal cyclone 12, and a suction port body 15 that sucks the non-magnetic toner 7 attached to the developing fur brush roller 6. , has a box 16 for storing non-magnetic toner 7 at its lower end. And this box 1
6 is connected to a Q meter 17 which measures the charge accumulated in the cyclone 12 and measures the amount of toner charge.

Therefore, the toner charge amount of the non-magnetic toner 7 adhering to the developing fur brush roller 6 is measured using this cyclone type charge amount measuring device, and the toner charge amount is in the range of 5 to 25 μc/gr. , the rotational speed of the charging roller 5, the contact width of the bristles 5a with the bristles 4a and 11, or the toner density. In this case, if the toner is less than 5 μc/gr, the toner will scatter and fog will occur, and if it is more than 25 μc/gr, it will not adhere to the photoreceptor side (development) and no image will be formed. Therefore, even in the case of continuous development, by setting the above conditions, development can be performed with the toner charge amount of the non-magnetic toner 7 in the range of 5 to 25 μc/gr, and the background of the image due to uncharged toner can be reduced. Fog can be prevented and stable image density can be obtained.

Note that in the above embodiment, the charging roller 5
As shown in FIG. The bristles 19 that rub against the bristles 11 of the developing fur brush roller 6...
It is also possible to have hair transplanted. In this case, by adjusting the length and density of the bristles 19 that rub against the bristles 11 of the developing fur brush roller 6, it is possible to develop the toner with a charge amount in the range of 5 to 25 μc/gr.

As explained above, this invention is capable of preventing background fog in images caused by uncharged toner by tribocharging toner and developing the toner with a charge amount in the range of 5 to 25 μc/gr, resulting in stable image formation. Image density can be obtained. Furthermore, there is an effect that a bias power source is not required and toner scattering is reduced.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view of a developing device showing an embodiment of the present invention, FIG. 2 is a front view of a cyclone type charge amount measuring device, and FIG. 3 is a sectional view taken along the line of FIG. 2.
FIG. 4 is a longitudinal sectional view of a developing device showing another embodiment of the invention. 1... Photoreceptor (image carrier), 6... Fur brush roller for development, 7... Toner.

Claims (1)

[Claims] 1. In a developing method in which a fur brush is used to supply toner to an image bearing member on which an electrostatic latent image has been formed to develop the electrostatic latent image, by rotating a roller on which a short hair fur brush is embedded. ,
A fur brush development method characterized by supplying toner triboelectrically charged in a charge amount range of 5 to 25 μc/gr to an image carrier to develop an electrostatic latent image on the image carrier.