JPS61138973A - Device for developing electrostatic latent image - Google Patents

Abstract

PURPOSE:To scrape surely a two-component developer from a sleeve by providing a developer scraping plate in sliding contact with a sleeve on the side nearer the progression side of the developer than the developing region on the sleeve and providing an impeller to such scraping plate on the side opposite from the sleeve. CONSTITUTION:An electrostatic latent image 34 is developed by the toner incorporated into the two-component developer 27 which is conveyed in a uniform layer on the sleeve 22 and arrives at the developing region 33. The two- component developer 27 remaining on the sleeve 22 is stripped from the sleeve 22 by the developer scraping plate 24. The developer 27 moved onto the plate 24 is pushed out toward the direction parting from the magnetic field of a magnet 23 by the impeller 25 rotating in an arrow 29 direction and falls to the bottom of a developing device 32 and therefore the developer does not stagnate near the plate 24.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an electrostatic latent image developing device using a two-component developer.

Conventional technology An example of a conventional electrostatic latent image developing device is shown in FIG.

This electrostatic latent image developing device consists of two components: toner and carrier.
A cylindrical sleeve 2 that holds a component developer 7 and moves the developer by rotation, and a sleeve 2 that is arranged concentrically inside this sleeve 2, sucks the developer onto the sleeve 2, and corresponds to the sleeve 2. The magnet 3 that rotates and the electrostatic m*
14, and a developer scraping plate 4 provided on the advancing side of the two-component developer from the image area 11 in sliding contact with the sleeve 2. The two-component developer 7 conveyed by the wheel 6 is supplied to the sleeve 2, and is conveyed in the direction of an arrow 8 by rotation of the sleeve 2 and magnet 3.

The two-component developer 7 is made uniform in layer thickness by the regulating blade 1 before reaching the developing section 11, where the toner contained in the two-component developer 7 adheres to the electrostatic latent image 14 and develops it. I do. The two-component developer 7 remaining on the sleeve 2 is scraped off to the bottom of the developing device 12 by the developer scraping plate 4, and returned to the stirring impeller 6 by the conveying impeller 6, thereby making the toner concentration uniform. At the same time, the toner is charged by friction with the carrier.

By the way, in order to improve the quality of development of the electrostatic latent image 14,
It is necessary to maintain the toner concentration of the two-component developer 7 with high accuracy in the development area 11. On the other hand, since toner is consumed for development in the developing section 11, the toner concentration of the two-component developer immediately after the developing section 11 is decreasing. From this, development area 1
In order to restore the toner concentration of the two-component developer used in step 1 to a predetermined value, the two-component developer 7 that has passed through the development area 11 is collected from above the sleeve 2 by the toner scraping plate 4 and removed from the developing device 1.
2 and the remaining two-component developer 7. In this way, the toner density is maintained.

Problems to be Solved by the Invention However, according to the electrostatic latent image developing device described above, the two-component developer 7 falls on the developer scraping plate 4 due to its moving speed and own weight due to changes in fluidity, for example. If the balance between the attraction between the blade and the magnet 3 is different, the developer will accumulate near the scraper plate 4.
It becomes impossible to scrape off the subsequent two-component developer 7.

To solve this problem, the attractive force of the magnet 3 can be reduced by reducing the magnetic force of the magnet 3, increasing the transport speed of the two-component developer 7, and selecting a two-component developer 7 with appropriate mechanical and magnetic properties. It is conceivable to overcome this problem and scrape off the developer 7. However, when the magnetic force of the magnet 3 is reduced and the conveyance speed of the developer 7 is increased, the development characteristics also change. In addition, a developer 7 having appropriate mechanical and magnetic properties
Similarly, dealing with this problem also causes a change in the development characteristics.

The present invention was made to solve the above problems, and
It is an object of the present invention to provide an electrostatic latent image developing device that can reliably scrape off a two-component developer from a sleeve without changing the characteristics of the two-component developer.

Means for Solving the Problems The present invention includes a cylindrical sleeve to which a two-component developer is attached and moves the two-component developer by rotation, and a sleeve that sucks the two-component developer onto the sleeve and corresponds to the sleeve. a developer scraping plate provided in sliding contact with the sleeve on the advancing side of the two-component developer from the development area on the sleeve at a position corresponding to the electrostatic latent image;
An electrostatic latent image developing device includes a developing device that stores component developers, and a stirring member for the two-component developer that is built into the developing device. It was established.

Effects The effects of this technical means are as follows. A two-component developer consisting of toner and carrier is conveyed to a developing area by a cylindrical sleeve provided with a magnet inside. The two-component developer that has not adhered to the electrostatic latent image in the developing area is separated from the sleeve by a developer scraping plate provided in sliding contact with the sleeve, and is blown off to the bottom of the developing device by an impeller. Therefore, some of the two-component developer that was pulled away from the sleeve first is not completely scraped off and does not stay near the scraping root, so it does not interfere with the subsequent scraping of the two-component developer. . Moreover, the effect of the invention is further enhanced by arranging the developer scraping plate in a curved shape along the rotational circumference of the impeller.

Embodiment FIG. 1 is a block diagram of an electrostatic latent image developing apparatus according to a first embodiment of the present invention. This electrostatic latent image developing device includes a cylindrical sleeve 22 that holds a two-component developer 27 consisting of toner and a carrier and moves the two-component developer by rotation, and a concentric ring inside the sleeve 22. Place and sleeve 2
a developing area 33 on the sleeve at a position corresponding to an electrostatic latent image 34 formed on a photosensitive drum or the like; A developer scraping plate 2 is provided in sliding contact with the sleeve 22 on the advancing side of the two-component developer from the development area 33.
4 and an impeller 252 provided on the opposite side of the sleeve 22 with respect to the developer scraping plate 24. The component developer 27 is rotated in the direction of arrow 30 of the stirring impeller 26, which is a stirring member for the two-component developer 27. Move onto the sleeve 22. The two-component developer 27 on the sleeve 22 is conveyed in the direction of the arrow 28 and reaches the development area 33 after the developer layer is made uniform by the regulating blade 21 . 2M, the toner contained in the developer 27 adheres to the electrostatic latent image 34 in the development area 33, and development is performed.

The developer 27 remaining on the sleeve 22 is separated from the sleeve 22 by the developer scraping plate 24. The two-component developer 27 that has been separated from the sleeve 22 and moved onto the VT developer scraping plate 24 is shown by the arrow 29.
It is pushed away from the magnetic field of the magnet 23 by the impeller 25 rotating in the direction , and falls to the bottom of the developing device 32 . The two-component developer 27 has reached the bottom of the developing device 32
The toner is stirred with the two-component developer 27 left in the developing device 32 and the stirring impeller 26, and the toner is charged by frictional charging with the carrier, and after recovering to a predetermined toner concentration, it is mixed again. It is conveyed to the sleeve 22.

FIG. 2 shows a developing device according to a second embodiment of the invention.

In the developing device shown in FIG. 2, the developer scraping plate 31 is formed to be curved along the rotational circumference of the impeller 25, and the other members are the same as the developing device shown in FIG. The structure is indicated by the same reference numerals. This developing device is
Since the developer scraping plate 31 is curved and provided along the rotating circular paper of the impeller 25, the two-component developer 27 separated from the sleeve 22 can be easily moved out of the magnetic field of the magnet 23, making it more reliable. You can scrape it off.

Effects of the Invention According to the present invention, the impeller is provided on the side opposite to the sleeve with respect to the developer scraping plate, and the two-component developer separated from the sleeve by the impeller stays near the developer scraping root. This has the effect of being able to reliably scrape off without scraping.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of an electrostatic latent image developing device according to a first embodiment of the present invention, FIG. 2 is a block diagram of an electrostatic latent image developing device according to a second embodiment of the present invention, and FIG. FIG. 1 is a configuration diagram of a conventional electrostatic latent image developing device. 22...Sleeve, 23...Magnet, 24...Developer scraping plate, 26...
... Impeller, 26... - Stirring impeller, 31.
...Developer scraping plate, 32...Developer.

Claims (3)

[Claims] (1) A cylindrical sleeve to which a two-component developer is attached and which moves this developer by rotation, and a cylindrical sleeve arranged concentrically inside this sleeve to attract and hold the developer onto the sleeve. A magnet that rotates in response to the
a developer scraping plate provided in sliding contact with the sleeve on the advancing side of the developer from the development area on the sleeve corresponding to the electrostatic latent image; and a developing device incorporating the sleeve and storing the developer. and an electrostatic developing device which is built in the developing device and includes a stirring member for the developer, characterized in that an impeller is provided on the side opposite to the sleeve with respect to the developer scraping plate. Latent image developing device. (2) The electrostatic latent image developing device according to claim 1, wherein the developer scraping plate is a curved developer scraping plate. (3) The electrostatic latent image developing device according to claim 2, wherein the developer scraping plate is a toner scraping plate constituted by a curved surface formed along the rotational circumference of the impeller.