JPH0584905B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a developing device for developing a latent image formed by electrophotography, electrostatic recording, or the like. More specifically, the invention relates to preventing scattering of developer from a developing device.

(Prior art) Conventional methods for developing electrical latent images include a wet development method in which toner particles are dispersed in insulating petroleum and transported to the surface of a latent image carrier for development, or a method in which magnetic particles and toner are used to develop the image. There are wet developing methods in which a developing agent is conveyed to the surface of a latent image carrier for development, but wet developing methods have been sluggish due to environmental hygiene issues and large contamination within the equipment, and currently dry developing methods are almost no longer in practical use. ing. However, this dry development method also involves mixing and stirring powder magnetic particles and toner.
Since the toner is conveyed to the surface of the latent image carrier by a magnetic generating means or the like, toner contamination within the apparatus cannot be avoided. To solve this problem, a developing device has been proposed in which a cover is provided along the outer periphery of the developer carrying member, and the developer is constantly rubbed against this cover. It is difficult to keep the toner constant all the time, and if the gap between the cover and the developer carrying member is wide, the developer cannot rub against the cover, and scattered toner accumulates on the inner wall of the cover, causing it to fall and form copy images, etc. This resulted in problems such as the appearance of aggregated toner clumps. Further, when the gap is narrow, the developer is removed by the cover, making it difficult to uniformly coat the developer carrying member. Therefore, it is complicated to adjust the position of the cover depending on the thickness of the developer. It has also been proposed to provide a flexible member at the tip of the cover in contact with the surface of the latent image carrier, but if there is a gap between the flexible member and the developer on the developer carrier, scattered toner may accumulate. , this has become a problem such as appearing in copied images.

(Objective) An object of the present invention is to improve the drawbacks of the above-mentioned conventional examples and to provide a stable developed image without scattering inside the machine and without toner contamination on images copied by a copying machine.

(Summary of the Invention) A developing device of the present invention that achieves the above object includes: a container portion that stores a developer; a rotating developer carrying member that carries and conveys the developer supplied within the container portion;
The developer carrying member is provided at a developer outlet section for carrying out the developer from the container section, and includes a layer thickness regulating member that regulates the layer thickness of the developer carried by the developer carrying member, In a developing device that supplies developer to the surface of the electrostatic latent image holder in a developing region located in a descending rotating portion of the carrying member, the outer circumferential surface of the developer carrying member is exposed from above outside the developer outlet portion. a first flexible sealing film that is attached to the cover member so as to protrude from the cover member and whose tip portion is brought into contact with the surface of the electrostatic latent image carrier above the development area; is located below the cover member and the first flexible sealing film, and is provided so as to be in contact with the developer layer on the developer carrying member from above from immediately after the developer outlet portion to the tip portion; and a second flexible seal film whose tip end is brought into contact with the surface of the electrostatic latent image holder near the development area.

(Example) The present invention will be explained below based on examples.

FIG. 1 is a sectional view of one embodiment of the developing device of the present invention. A is a latent image holding body, such as a drum-shaped or belt-shaped photoreceptor or an electrostatic recording dielectric;
It is driven in the direction of the arrow, a latent image is formed by an image forming process device (not shown), and the latent image is developed by the developing device B as a visible image.

In the developing device B, reference numeral 1 denotes a developing container, and the inside thereof is divided by a septum 2 into a toner storage section 3 and a developer storage section 4 that stores a developer consisting of toner and magnetic particles. The toner in the toner storage section 3 is transported toward the partition wall 2 by toner transport members 6 ₁ and 6 ₂ and is replenished into the developer storage section 4 from the toner replenishment port 16 .

Reference numeral 7 denotes a developer carrying member, which is composed of a developing sleeve ₇₁ made of a non-magnetic material and containing a magnet roll ₇₂ . S ₁ to S ₂ and N ₁ to _{N 3} indicate the magnetized positions of the magnet roll ₇₂ .

The magnet roll ₇₂ is fixedly supported at both ends and does not rotate, and the developing sleeve ₇₁ is driven to rotate around the magnet roll ₇₂ at a predetermined circumferential speed in the direction of the arrow.

Reference numerals 8 and 9 are rotatably driven in the direction of the arrow in the developer storage portion ₄ by screws, which are developer agitation and conveyance means arranged substantially parallel to the developing sleeve 71. A developer circulation regulating member 17 is provided between the upper and lower screws and regulates the developer circulation path.

10 and 14 are developer circulation area designating members on the circumferential surface of the developing sleeve ₇ in the developing storage section 4;
Reference numerals 1 and 13 refer to magnetic members, magnets, for preventing the developer from leaking toward the latent image holder A from the developer storage portion 4, and 12 refers to a magnet for regulating the layer thickness of the developer formed on the circumferential surface of the developer sleeve. It is a non-magnetic blade.

15 is a sensor that detects the concentration of developer (mixing ratio of toner and magnetic particles) in the developer container;
Depending on the output of this sensor, the toner conveying member 6 ₁ ,
6 Controls the operation of ₂ .

When the developing device is in operation, the developing sleeve 7 ₁ and the screws 8 and 9 are each driven to rotate, and an alternating voltage is applied between the developing sleeve 7 ₁ and the latent image holder A.

The developer mixed and stirred by the screws 8 and 9 moves over the developing sleeve ₇₁ ,
The latent image is uniformly applied onto the sleeve by the regulating member A, and the latent image is developed near the magnetic pole N ₂ (hereinafter referred to as the developing pole) facing the surface of the latent image carrier A. Reference numeral 18 denotes a scattering prevention cover provided to prevent the developer from scattering on the developing sleeve ₇₁ , which is regulated at a constant coating thickness by the regulating member 12. A first flexible sealing film 19 made of Mylar or the like with a thickness of several microns to 200 microns is in contact with the latent image carrier. Further, a second flexible sealing film 20 made of Mylar or the like having a thickness of several microns to 200 microns, preferably 10 microns to 50 microns, is fixed to the part 18a of the scattering prevention cover 18 by adhesive or the like, and the developing sleeve 7. While making contact with the developer on ₁ , install it up to the part where the latent image holding member A and the developing sleeve face each other (near the developing area of _N2 ). More specifically, the second flexible sealing film 20 is configured so that it comes into contact with the latent image holder near the developing area and is sandwiched between the developer on the developing sleeve ₇₁ and the latent image holder. Become. In this way, the developer on the developing sleeve ₇₁ is covered with and in contact with the second flexible seal film 20, so that toner does not accumulate. Further, in the portion of the second flexible sealing film 20 that is in contact with the latent image carrier, a developing magnetic pole is formed.
A developer pool forms slightly upstream of N ₂ , but when the developer coating on the developing sleeve is thick, this developer pool expands and lifts the tip of the second flexible sealing film 20 . A slight gap is created between the leading edge of the film and the latent image holder, and toner may leak upward through this gap. Also second
The flexible member may wave in the longitudinal direction of the developing sleeve, and at this time, some toner is scattered on the upper part. However, even if such leakage occurs, the first flexible sealing film 19 is disposed above the second flexible sealing film 20 in contact with the latent image holder, so that the upper part of the developer container is Toner scattering can be completely prevented. On the other hand, the toner that leaked from the tip of the second flexible sealing film 20 and flew upwards gradually accumulates on the cover 18 and the inner surface of the first flexible sealing film 19. When the toner has grown to a certain extent and is subjected to vibrations or the like, it may fall off in chunks, but in the past, the toner that fell in this way caused patchy stains on the developed image. However, the second
Since the tip of the flexible seal film 20 is in contact with the surface of the latent image carrier, the fallen toner lumps cannot pass through the developing area all at once, but are suppressed to enter the developing area little by little. , it is possible to prevent mottled stains from occurring on the developed image.

The first flexible sealing film 19 is made of mylar with a straightness of 50μ, and the second flexible sealing film 20 is made of more flexible mylar with a thickness of about 20 to 30μ. The desired purpose was achieved without applying unnecessary weight to the developer.

Furthermore, by disposing the second flexible sealing film 20 in contact with the developer, the developer can be coated on the developing sleeve extremely uniformly and without any unevenness. I was able to reproduce a copy image without .

It goes without saying that the abutment positions and support methods of the first and second flexible seal films are not limited to these.

Further, although Mylar was a good material for the flexible sealing film, it is not limited to this as long as it is an insulating flexible sealing film.

(Effects) As explained above, according to the present invention, the developing device has an extremely simple configuration, does not require an adjustment mechanism, can prevent scattering of the developer in the developer, and stably provides high-quality images for a long period of time. can be configured. Moreover, it goes without saying that it is low cost and has excellent maintainability.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a developing device showing one embodiment of the present invention. A ...Latent image holder, B ...Developing device, 7 ₁ ...
Developing sleeve (developer carrier), 18... Sleeve cover (cover member), 19... First flexible sealing film, 20... Second flexible sealing film, 18a... Second flexible sealing film Flexible seal film support part, shaded area...developer.

Claims (1)

[Claims] 1. A container section that accommodates a developer, a rotating developer carrying member that carries and conveys the developer supplied within the container section, and a developer outlet section through which the developer carrying member carries out the developer from the container section. a layer thickness regulating member for regulating the layer thickness of the developer conveyed by the developer carrying member; In the developing device that supplies developer to the developer, a cover member that covers the outer circumferential surface of the developer carrying member from above outside the developer outlet portion; and a cover member that is attached to the cover member so as to protrude from the cover member; a first flexible sealing film whose tip portion is brought into contact with the surface of the electrostatic latent image holder above the development area; a first flexible sealing film located below the cover member and the first flexible sealing film; The second electrode is provided so as to be in contact with the developer layer on the developer carrying member from immediately after the developer exit portion to the tip end, and the tip portion is brought into contact with the surface of the electrostatic latent image carrier near the development area. 2
A developing device comprising: a flexible seal film;