JPS58194069A - Developing device of electrophotographic copying machine - Google Patents

Abstract

PURPOSE:To detect accurate toner density by gathering a developer which is scraped off from a magnet roll with a scraper to one side part of a developing tank with a stirring rod, and arranging a toner density sensor on the side where the developer is gathered. CONSTITUTION:The developer after being carried by the magnet roll 13 and used for the development of a photosensitive drum 1 is scraped off with the scraper 14. Stirring rods 17 and 18 which have spiral stirring vanes are provided behind the scraper and under a toner hopper and their stirring and carrying diretions for the developer are set oppositely. The toner density right after toner is supplied from the toner hopper is highest at one side of the tank where the toner is gathered by the rod 17. A density sensor 15 is provided in the tank where the toner density is highest to facilitate the detection.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a developing device in an electronic copying machine. The developer that is in this product's developing device is made of carrier and toner, and is made of iron as the 5th and 4th degree king. It is a polymer powder coated with an RT-treated film (θ1 polymer) and colored with a 17% polymer. When Yayaya and toner are mixed and stirred, they rub against each other and have a -1if load. Non-A1 on the photosensitive drum. When '-selenium is used, the toner and carrier are selected so that the toner is negatively charged and the carrier is positively charged. Changing the mixture ratio of toner and carrier changes the image. If the toner ratio is low, the image density will decrease and streaks will become noticeable. If the proportion of toner is too high, it may cause soil bleed or cause dirt inside the machine.

Therefore, it is necessary to keep the mixing ratio of toner and carrier as constant as possible.

Toner is consumed in the developing device, and new toner is repeatedly replenished. When new toner is replenished into the developing device, agitation creates friction and imparts a sufficient charge to the toner. As mentioned above, the toner concentration in the developer is extremely important in obtaining high-quality images, and in order to obtain a large amount of stable images, it is necessary to maintain the toner concentration constant at all times. It is an object of the present invention to provide a developing device for an electronic copying machine that can meet this demand.

Embodiments of the present invention will be described with reference to the drawings. FIG. 1 shows an electronic copying machine equipped with a developing device of the present invention. In FIG. 1, a photosensitive drum made of amorphous selenium rotates in the direction of an arrow α. 2 is a charging device, and when a high voltage of 1F is applied, 11 charges of j' are applied to the photosensitive drum 1. The image of the original 3 is a mirror 4.5.6.7.8.9 and lens I> and one slit 11 [7] An image is formed on the photosensitive drum 1, and an electrostatic latent 1&4 m- is formed. 12 is a developing device, and the developer is supplied by a magnet roll 13 rotating in the direction of the arrow. The image is placed on the photosensitive drum 1 and the Seiden Statue is made visible.At this time, the photosensitive drum 1
Only #j toner adheres to the magnetic L-roll 15, and the carrier remains on the magnetic L-roll 15. As development is repeated, the amount of toner in the developer decreases, so new toner is replenished. 14k"
The surface of the magnet roll 15 is provided so as to be in sliding contact with the magnetic roll 16. Dark I fly sensor 1 to detect
5 ゛ is the setting. -〇Density sensor 15 detects toner hopper 1 depending on the number of months detected.
The toner supply by 6 is controlled to maintain a constant mixing ratio of toner and carrier.

17.18d: Mix the replenished toner and developer with a stirring rod. The toner adhering to the photosensitive drum 1 is transferred onto copy paper by a transfer charger 19.

A separating charger 20 separates the copy paper from the photosensitive drum 1. The image on the copy paper separated from the photosensitive drum 1 is fixed by a fixing device 21. The photosensitive drum 1 is neutralized by a static eliminator 22, cleaned by a cleaner 25, and the copying operation is completed.

Next, the developing device of the present invention will be explained with reference to FIGS. 2 and 5. The developing device 12 includes a magnet roll 15 that is axially mounted between a front side plate 24 and a rear side plate 25, and two stirring rods 17.
18, a scraper 14 provided in sliding contact with the magnet roll 13, and a concentration center 15. The magnet roll 13 has a permanent magnet fixed therein by a knob 26, and the outside is a rotating non-magnetic sleeve. The stirring rods 17 and 18 have a driving gear 27 at the shaft end.
．． It has 2B. The concentration sensor 15 is a coil wound around an iron core, and detects changes in magnetic permeability caused by changes in the mixing ratio of toner and carrier in the developer.

- 29i1: container of the developing device; 50 is its cover;

The developer is stirred and mixed by a stirring rod 17.1B, and is applied onto the photosensitive drum 1 through the space between the magnet roll 13 and the doctor blade 51. After development, the developer adhering to the magnet roll 13 is scraped off by a scraper 14. When the density sensor 15 detects that the toner density has decreased, a replenishment roller 34 provided in the dropper 16 is driven to supply new toner. 52 is a sealing member that prevents the toner from leaking from the gap between the hot spring 16 and the container 29. 35 is a kite plate.

Stirring rod 17.181 As shown in Figure 5, it has spiral stirring blades. The first stirring rod 17 provided below the hopper 16 and behind the scraper 14 rotates in the direction of arrow C (7,
The toner supplied from the direction of arrow e by the supply roller 34 is collected on one side (direction f) of the container. The toner collected on one side of the container is moved to the other side of the container by a second stirring rod 18 provided below the first stirring rod 17.
y direction). That is, the second stirring rod 18 rotates in the d direction, which is the opposite direction to the first stirring H-+117. Note that when the spiral directions of the stirring blades of the first stirring rod 17 and the second stirring rod 18 are opposite, they rotate in the same direction. The toner concentration immediately after toner is replenished from the hopper 16 is the first
One side of the container where the toner is collected by the stirring bar 17 is highest. The concentration sensor 15 is provided at a location within the container 29 where the toner concentration is highest to facilitate its detection.

As described above, the present invention provides electronic copying in which toner, carrier, and developing agent are applied to the surface of the photosensitive drum 10 on which the electrostatic latent image is formed by applying it to the magnet roll 15 to visualize the electrostatic latent image. In the machine, a container 2 of a developing device accommodates the magnet roll 13 and supports it rotatably.
9, a hopper 16 for feeding the toner (J) into the container 29, a scraper 14 for scraping off the developer remaining on the magnet roll 15, and first and second stirring blades having spiral stirring blades. rods 17, 18 and a concentration sensor 15 for detecting the concentration of toner in the developer, the first stirring rod 17 is connected to the scraper 1 below the hopper 16.
The developer is stirred and mixed so as to collect the developer on one side of the container 29, and the collected developer is transferred to the container 2.
The IW sensor 15 is disposed on one side of the container 29 where the developer is collected by the first stirring rod 173, and measures the toner concentration in the developer. Configured to detect.

Since the developing device of the present invention has the above configuration, the developer in the container and the supplied toner are collected on one side of the container by the first stirring rod 17, mixed and stirred, and the developing device is developed at the most effective position. By detecting the toner concentration in the developer and controlling the amount of toner replenished, the toner concentration in the developer can be kept uniform. As a result of experiments, it was possible to control the toner concentration in the developer to an ideal range of 35-45 cm.
When 0.000 sheets were continuously copied, it was confirmed that there was almost no difference in image quality between the initial copy and the final copy.

[Brief explanation of drawings]

No. 1N: A side view of an electronic copying machine equipped with the developing device of the present invention. FIG. 2: A side view of an embodiment of the developing device of the present invention. No. 3N: A plan view of an embodiment of the developing device of the present invention [Symbol] 1 ... Photosensitive drum, 2... Charger, 3... Document, 4.5.6.7.
8.9...Mirror, 10...Lens, 11...Slit, 12...Developer, 13...Magnet roll, 14...Scraper, 15...Density sensor, 1
6... Toner hopper, 17... First stirring rod, 18.
...Second stirring bar, 19...Transfer charger, 20...
Separation charger, 21... Fixing device, 22... Static eliminator,
23.--Cleaner, 9-

Claims (2)

[Claims] (1) Apply toner and carrier to the surface of the photosensitive drum, where an electrostatic latent image is formed, and a developer to a magnetic roll.
In an electronic copying machine in which the electrostatic latent image is visualized by applying the magnet roll to the container, a hopper for supplying toner to the container of a developing device that houses the magnet roll and rotatably supports the magnet roll, and a hopper that supplies toner to the container; A scraper for scraping off the remaining developer adhering to the roll, first and second stirring rods having spiral stirring blades, and a concentration sensor for detecting the concentration of toner in the developer are provided. A stirring bar is located below the hopper and behind the scraper to agitate and mix the developer to collect it on one side of the container, and the second stirring bar is located below the first stirring bar. 1. Transfer the developer collected on one side of the container to the other side.
- the concentration sensor is arranged on one side of the container in which the developer is collected by the first stirring bar and is configured to detect the positioning of the toner in the developer; A developing device for an electronic copying machine featuring (2) The density sensor is composed of a coil wound around an iron core, and detects changes in magnetic permeability based on changes in l/toner concentration IW in the developer, and controls the supply of toner by the output of the sensor. A developing device for an electronic copying machine according to claim (1), characterized in that: