JP3218470B2 - One-component developing device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a one-component developing apparatus that develops an electrostatic latent image formed on a latent image holding member into a visible image with toner in an electrophotographic apparatus. It is.

(Prior Art) As disclosed in JP-A-47-13088 and JP-A-53-167341, toner is sent to a holder by a carrier to form an electrostatic latent image on the holder. A one-component developing device for developing a visual image is known.

In such a one-component developing apparatus, there is a serious problem that toner spills from the developing apparatus or toner scatters in a copying machine due to toner spilling from a thin toner layer formed on a toner carrier by a regulating member. . To prevent this, as described in JP-A-55-115061, there is a device in which a seal member made of a soft elastic material is provided below the toner carrier. In particular, spillage of toner from the toner layer is not used for developing an electrostatic latent image on the latent image holding member among toners flying by a developing electric field in an area near the toner holding member and the latent image holding member, and In many cases, toner that cannot return to the carrier drops due to gravity or the flow of air due to the rotation of the toner carrier and the latent image holder, as described in Japanese Utility Model Laid-Open No. 165553/1986. To prevent toner contamination inside the copying machine by providing a toner collecting means below the developing device, or as described in Japanese Patent Application No. 64-206843, a corotron facing the toner carrier just below the developing area. An electrode such as a wire is provided, and the toner that has not been used for development among the toner flying in the development area is forcibly returned to the toner carrier by an electric field created between the electrode such as a corotron wire and the toner carrier. , Multiple Attempts have been made to reduce toner scattering inside the copying machine.

However, in Japanese Utility Model Laid-Open Publication No. Sho 61-165553, it is difficult to stably prevent the toner from spilling except for providing the toner collecting means below the developing device. Therefore, it is not suitable especially when a developing device needs to be miniaturized like a full-color copying machine.

SUMMARY OF THE INVENTION It is an object of the present invention to reliably prevent toner from spilling without increasing the exclusive space of the developing device main body in a copying machine.

(Means for Solving the Problems) Here, the toner that is not developed into the latent image of the latent latent image holding member on the downstream side of the developing area and cannot return to the toner carrier roll is generated by the rotation of the two. An elastic toner seal member that passes through a space called an air flow path formed between the toner scattering prevention plate provided to receive an air flow and the toner carrier and contacts the surface of the toner carrier at the end of the air flow path. And the elastic toner seal member is arranged via a space from the accumulated toner surface of the storage section for storing the toner in the developing device, so that the toner can be returned to the developing device. In order to further enhance the effect of the present invention, a bias having a polarity opposite to that of the toner is applied to the toner scattering prevention plate.

The toner used in the present invention is a non-magnetic one-component or two-component developing type toner in which only the toner is adhered to the toner carrier and developed, and is particularly used for the non-magnetic one-component toner. However, if necessary, a magnetic toner may be contained, and a color toner and a capsule toner can also be used.

In order to solve the problems of the related art, the present invention provides a latent image holding member that holds an electrostatic latent image, and a toner holding member that rotates so as to move in the same direction as the latent image holding member on an opposing surface. Body, a toner scattering prevention plate having an end extending to a position close to the surface of the latent image holding member, and air blocked by the toner scattering prevention plate in order to dam the air flow generated by the rotation of the two. A flow passage for guiding the flow into the developing device, the latent image holding member air flow path formed between the toner scattering prevention plate and the toner carrying member, and an air flow path close to the latent image holding member surface; The toner in the developing device, which is in contact with the surface of the toner carrier disposed at the end opposite to the side and stores the toner in the developing device via a space from the accumulated toner surface of the storage unit, is externally charged. Elastic shell to prevent And seal member, a one-component developing apparatus comprising a.

(Effect) The scattered toner generated in the developing area is carried to the elastic seal member at the end through the air flow path by the flow of air due to gravity or rotation of the toner carrier and the latent image carrier, and partially. The scattered toner is directly developed by a laminar flow formed on the surface of the toner carrier which can flow into the developing device because the pressure on the carrier of the elastic seal member is sufficiently small and has a space inside. It can flow into the device.

(Embodiment 1) FIGS. 1 and 2 are general explanatory views of a one-component developing device using a non-magnetic toner according to the present invention. The developing device is supplied from a toner storage box outside the developing device by a supply auger 7 into the developing device. The transported toner 1 accumulates in the hopper 15 and is uniformly dispersed at a height regulated by the overflow position. The supply member 6 pumps the toner 1 in the hopper 15, and the toner 1 is supplied to the toner carrier 4 by an electric field between the toner carrier 4 and the toner carrier 4 generated by the supply member bias 12. As a result, a thin layer of the toner 1 is formed on the toner carrier 4. The toner 1 formed in a thin layer on the toner carrier 4 is
The electrostatic latent image 2 held on the latent image holding member 3 is developed by the developing bias 11. Here, in the toner 1 flying by the developing bias, the toner 1 is not used for developing the electrostatic latent image 2,
In addition, the toner 1 that cannot return to the toner carrier 4 becomes spilled toner 16, and the toner 1 on the toner scattering prevention plate 9 or the elastic seal member is caused by gravity or the flow of air generated by the rotation of the toner carrier 4 or the latent image carrier 3. A part of the toner is transported onto the toner carrier 10, a part of the toner directly passes between the toner carrier 4 and the elastic seal member 10, and falls into the developing device. Most of the toner is deposited on the toner scattering prevention plate 9 and the elastic seal member 10. When the toner 16 spills to some extent, the toner 16 passes between the toner carrier 4 and the elastic seal member 10 and falls into the developing device due to vibration or the like caused by the rotation of the toner carrier 4. The amount of the spilled toner 16 scattered in the copying machine depends on the gap between the tip of the toner scatter prevention plate 9 and the latent image holding member 3. When the spilled toner 16 is set to about 0.5 mm, the conventional elasticity as shown in FIG. The amount of toner scattered in the copier is 1 / compared to the case where a seal member is used.
When the conductive material is used as the toner scattering prevention plate 9 and a DC bias having a polarity opposite to that of the toner is applied by the scattering prevention plate bias 13, the toner scattering amount is further reduced, and +1000 V is applied. In the case, it was reduced to about 1/8 compared with the case where the conventional elastic seal member was used. An example of the toner is a non-magnetic one-component toner, in which a pigment such as carbon or a polarity controlling agent such as a metal-containing azo dye is dispersed in various thermoplastic resins such as styrene resin and acrylic resin. Then, it was made into a size of 5 to 20 μm from crushing and classification,
Charge control material is externally added. As the charge control material, fine particles of 0.1 μm or less, such as silica, alumina, and titanium, which have been subjected to hydrophobic treatment, are used, and hydrophobic silica is most preferable.

The toner carrier 4 usually has a diameter of 5 to 40 mm. After cutting a round bar of aluminum or stainless steel, the circumferential surface is subjected to machining such as sandblasting, liquid honing, emery polishing, or chemical corrosion. By Ra
It can be used to make irregularities of about 0.1 to 1.0 μm, or after cutting a round bar of aluminum or stainless steel, providing a semiconductive layer such as phenolic resin on the circumferential surface, and performing mechanical polishing such as emery polishing. It is used with a surface roughness of about 1 to 1.0 μm. In some cases, the aluminum roll is mechanically polished and then subjected to an anodic oxidation treatment. Carrier 4
When a semiconductive layer is provided on the carrier 4, the surface resistance of the surface layer of the carrier 4 in the thickness direction is about 10 ⁵ to 10 ¹² Ωcm. The rotation speed of the carrier was 100 to 300 rpm.

The restricting member 5 is made of a stainless steel leaf spring having a thickness of about 0.03 to 0.3 mm and vulcanized and bonded with Si rubber or EPDM rubber, and the contact pressure to the carrier 4 is set to about 20 to 200 g / cm. The toner 1 is formed into a thin layer of about 10 to 30 μm by the regulating member 5 and is given a charge of about 2 to 20 μc / g.

As the electrostatic latent image holder 3, a Se-based photoconductor or an organic photoconductor is generally used, and the latent image holder 3 and the toner carrier 4 are usually opposed to each other with a gap of about 100 to 300 μm.

The toner supply member 6 is a molded product such as urethane foam having a diameter of about 10 to 20 mm, and a supply member bias port may be applied between the toner supply member 6 and the carrier 4 in order to increase the toner supply rate. The shape of the supply member 6 is not limited to a cylindrical shape, and may be, for example, a member provided with blades parallel to the axial direction on a circumferential surface of the same quality.
The depth is set so as to be about 0.5 mm into the toner carrier 4. Further, when a supply member bias is applied, urethane may contain carbon in an amount of 10 ⁴ to 10 ^8.
What is molded with urethane foam having a volume resistance of about Ωcm is used. The rotation speed was 1 to 4 times the rotation speed of the toner carrier 4.

The toner supply auger consists of a stainless steel shaft with a diameter of 6 mm and a spiral auger with a width of about 4 mm adhered to the auger.
The pitch is set to 0.5 mm, and the toner collecting auger 8 is formed by bonding a spiral auger having a width of about 4 mm and a pitch of 20 mm to a stainless steel shaft having a diameter of 6 mm.
A mechanism is provided in which the toner collected by the collection auger 8 is once carried out of the developing device, but is returned to the supply auger 7 again.

The toner scattering prevention plate 9 according to the present invention has a stainless steel plate or the like of about 0.2 to 1 mm adhered below the toner carrier 4 in front of the developing device, and the elastic sealing member 10 uses a 25 to 50 μm Mylar film. One end is adhered to the toner scattering prevention plate 9, and the other end is slightly in contact with the carrier 4.

In this example, a long-term print test was performed to check the temporal stability of the toner scattering prevention mechanism in the copying machine. As a result, toner scattering in the copying machine was small even after about 30,000 sheets. (See FIG. 5) (Effect of the Invention) By adopting the technical configuration of the present invention, the toner can be retained in the developing machine without being scattered in the copying machine, and the copy quality and the reliability of the machine are improved. I was able to.

[Brief description of the drawings]

FIG. 1 is an overall explanatory view of the developing device viewed from a side,
FIG. 2 is a block diagram of the present invention. FIG. 3 is an explanatory view of a conventional developing device corresponding to the present invention, and FIGS. 4 and 5 show test results showing the effects of the present invention. 1: toner, 2: latent image, 3: latent image holder, 4: toner carrier, 6:
Toner regulating member, 9: toner scattering prevention plate, 10: elastic seal member, 11, 12, 13: bias power supply

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Masashi Kajimoto 2274 Hongo, Ebina-shi, Kanagawa Prefecture Inside Fuji Xerox Co., Ltd. (56) References JP-A-61-165779 (JP, A) JP-A-64-49066 (JP, A) JP-A-63-120266 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) G03G 15/08

Claims (1)

(57) [Claims] 1. A latent image holding member for holding an electrostatic latent image, a toner carrier rotating so as to move in the same direction as the latent image holding member on an opposing surface, and an air flow generated by rotation of the two. A toner scattering prevention plate having an end extending to a position close to the surface of the latent image holding member, and an air flow blocked by the toner scattering prevention plate for guiding the air flow into the developing device. A latent image carrier air passage formed between the toner scattering prevention plate and the toner carrier; and an air passage provided at an end of the air passage opposite to a side close to the surface of the latent image carrier. An elastic seal member that is in contact with the surface of the toner carrier and that is arranged through a space from a deposited toner surface of a storage unit that stores the toner in the developing device via a space so as not to discharge the toner in the developing device to the outside; A one-component developing device.