JPH0693152B2 - One-component developing device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a one-component developing device, and in particular, a developer supplied onto a developer carrying member is formed into a developer layer having a predetermined thickness by a regulating member.
The present invention relates to a one-component developing device for visualizing a developer layer by attaching it to an electrostatic latent image.

[Prior Art] In an electronic copying machine or the like, a one-component developing device is used as one means for developing an electrostatic latent image into a visible image. 2. Description of the Related Art As a conventional one-component developing device, a device whose outline is shown in FIG. 2 is known (see Japanese Patent Application No. 59-150721).

In FIG. 2, a developer 1 is housed in a hopper 2, a developer carrier 4 facing the photoconductor 10, a carrier roll 3 for supplying the developer to the carrier 4, a developer on the carrier. A regulation member 5 that regulates the layer and imparts a charge of a predetermined polarity to the developer is provided. The developer carrier 4 and the transport roll 3 rotate in the directions of arrows A and B, respectively, and rotate in the same direction at their contact portions, and the developer 1 is transferred to the carrier 4 by the transport roll 3. The regulating member 5 contacts the carrier 4 with a uniform pressure in the axial direction thereof,
By this action, the developer 1 is formed into a predetermined uniform developer layer 6 on the carrier, and an electric charge is given to the developer. The uniform developer layer 6 pushes up the regulation member by mechanical force, passes between the developer carrying member 4 and the regulation member, and
It is conveyed to a position opposite to 10, and electrostatically adheres to the latent image on the photoconductor to be developed.

[Problems to be Solved by the Invention] In such a conventional one-component developing device, a two-layer structure in which a soft elastic body 8 is joined to a leaf spring material 7 is used as the regulating member 5, and the leaf spring is used. The elastic force of the material 7 brings the soft elastic body into contact with the carrier 4 at a predetermined linear pressure in the range of 50 to 500 g / cm to regulate the developer layer.

The pressure with which the regulating member 5 contacts the carrier 4 has a great influence on the state of the developer layer, and when the contact pressure is not uniform, the formed developer layer is not in a uniform state, and the copy image is disturbed. It is extremely important to maintain a uniform contact pressure, because it causes fogging of the background part.

However, when the conventional regulating member is used for a long time, the sliding portion (soft elastic body) with the carrier wears, and the elastic force (contact pressure) decreases by an amount corresponding to the worn depth,
As a result, there is a problem that the developer layer thickness becomes large, and fog in the background portion on the copy and uneven density occur.

Therefore, an object of the present invention is to provide a one-component developing device that can always obtain a uniform contact pressure between the regulating member and the developer carrying member and can form a uniform developer layer for a long time. To do.

[Means for Solving Problems] The inventors of the present invention reduce the influence of the contact pressure of the regulating member due to the wear amount of the soft elastic body depending on how the length and the thickness of the leaf spring material are set, and provide a stable contact pressure. The present invention has been completed, finding that it can be obtained over a long period of time.

That is, in the present invention, a metal material having elasticity is used as the leaf spring material of the regulating member, the length l (mm) from the supporting end of the leaf spring material to the supporting member contact portion of the leaf spring material, and the thickness of the leaf spring material. In the one-component developing device, a regulating member is set so that l ≧ 10 and the relation expressed by the following equation 100 ≦ l / t ≦ 500 is satisfied, where t is (mm). is there.

The present invention will be described below with reference to the drawings.

FIG. 1 is a schematic diagram of a non-magnetic one-component developing device in which the setting conditions of the regulating member according to the present invention are obtained.

This device has the same structure as the conventional device shown in FIG. 2, but as a developer regulating member, as shown in an enlarged view of FIG. The length (free length) to the contact portion of is 1 (mm) and the thickness is t (mm).

In the conventional device, the free length l of the leaf spring material of the regulating member is 10 mm.
Although the contact pressure is set to a predetermined value below, the inventors of the present invention set the free length of the leaf spring material to be larger than that of the conventional device by a preliminary experiment so that the wear amount of the soft elastic body can be reduced. It was confirmed that the influence on the contact pressure was reduced. However, simply increasing the free length is not practical. Therefore, we considered that there are appropriate conditions for the elastic modulus, free length and thickness of the leaf spring material, and decided to try a copy test under various conditions using a non-magnetic one-component developer.

Prior to the description of the copy test, the non-magnetic one-component developing device shown in FIG. 1 will be briefly described.

In FIG. 1, the developer 1 contained in the hopper 2 is
Particles having a size of about 5 to 20 μ in which a pigment such as carbon or a polarity control agent such as a metal-containing azo dye is dispersed in various thermoplastic resins such as styrene or acrylic resin. Is hydrophobic silica.
You may add 5 to 20 weight%.

The developer 1 is supplied to the carrier by gravity from a hopper 2 provided directly above the developer carrier 4.

The transport roll 3 has a structure in which an elastic body such as urethane rubber is adhered in a cylindrical shape to a metal cored bar, and rotates while being pressed against the surface of the developer carrier 4 with a predetermined pressure to supply the developer.

The developer carrying member 4 is formed by coating the surface of a solid or hollow cylindrical member made of iron with a semiconductive resin (phenol resin or the like) to a thickness of about 1 mm.

The regulation member 5 makes the developer on the carrier have a constant layer thickness and charges the developer by frictional charging.

As the leaf spring material that constitutes the regulating member 5, the elastic modulus is 7 ×.
10 ^{5 to} 3 × 10 ⁶ kg / cm ² of phosphor bronze, silicon steel, stainless steel, etc. are used, and as the soft elastic body, a silicone rubber base material, for example, KE650- which is a heat vulcanizing type silicone rubber is used.
U, KE850-U, KE554-U, KE555-U, KE752-U,
(Made by Shin-Etsu Silicone Co., Ltd.), TSE221, TSE270, TSE2
A material obtained by vulcanizing a base material such as 60 (above, manufactured by Toshiba Silicone Co.) containing an acid dye or the like is used.

When the developer layer formed on the developer carrier is conveyed to the position facing the latent image carrier 10 by the rotation of the carrier 4, the developer layer adheres to the electrostatic latent image on the carrier 10 and the electrostatic latent image is formed. The image is visualized.

The developer 1 that has passed through the development area and has not been used for development is removed from the surface of the carrier 4 by the transport rolls 3 and returned to the hopper 2 again.

Copy test In the constitution shown in FIG. 1, a negatively chargeable toner (average particle diameter 12 μm) containing 2% by weight of an azo dye and 10% by weight of carbon black in a styrene-acrylic binder as the developer 2 is used.
m), a carrier roll 3 in which an ethylene propylene die material (EPDM) rubber layer is adhered to the outer circumference of a stainless steel core metal, a developer carrier 4, a roll in which a phenol resin is made conductive, and a regulating member 5 having hardness Using 50 degree silicone rubber as a base material, knead 1.0% by weight of monoethanolamine with 3 rolls, heat in a mold,
After vulcanization, it was cut into a soft elastic body with a thickness of 1 mm, a width of 10 mm, and a length of 300 mm.The elastic modulus was 2.1 × 10 ⁶ Kg / cm ² , and the thickness was 0.
Free length l = 24 m for 2 mm stainless steel (SUS304CSP3 / 4HO)
Those bonded so as to have m, and as a comparative example, l = 5 mm
The contact pressure of the regulating member 5 to the carrier is 130 g / cm, and the peripheral speed of the developer carrier is 100 mm.
I did a copy test as / sec.

Fig. 4 shows the change in the amount of wear of the soft elastic body of the regulating member when copying up to 200,000 sheets, and Fig. 5 shows the change in the developer weight per unit area conveyed through the regulating member. Show.

The wear amount of the regulating member is almost unchanged at l = 24 mm and l = 5 mm (FIG. 4), but the developer transport amount is gradually increased when l = 5 mm (FIG. 5). As shown, the copy density is increased, and the background portion is fogged. On the other hand, when l = 24 mm, the contact pressure of the regulating member is not affected by the wear amount and is kept constant, the developer conveyance amount is almost unchanged (Fig. 5), and the copy density is 20%. It was almost constant during the copying of 10,000 sheets, and no fog was generated in the background portion.

Next, a copy test was similarly performed by changing the free length l and the thickness t of the leaf spring material, and when the wear amount of the soft elastic body reached a constant value of 80 μm, the amount of the developer conveyed on the carrier was determined. The fog on the copy background was measured. The results are shown in FIGS. 7 and 8.

It is clear from FIGS. 7 and 8 that under the condition of 100 ≦ l / t, a good copy without fog can be obtained for a long period of time. Under the condition of l / t> 500, it is difficult to obtain the required contact pressure due to the buckling of the leaf spring material.
It was found that the condition of 0 ≦ l / t ≦ 500 is suitable.

Further, in order to maintain the developer weight with a low background fog level of 0.95 mg / cm ² or less when the l / t is 100 or more,
As is clear from the figure, l must be 10 mm or more.

It should be noted that the above description is for a developing device that uses a non-magnetic one-component developer, but if a device that forms a developer layer by a developer regulating member also uses a magnetic developer or the like. It will be apparent to those skilled in the art that the present invention can be applied.

[Advantages of the Invention] In the present invention, the free length l of the leaf spring material of the developer regulating member is made larger than before (l ≧ 10 mm), and the ratio of thickness t to l (l / l
By setting t) from 100 to 500, we have provided a one-component developing device that reduces the effect of the wear amount of the soft elastic body of the regulating member on the contact pressure, and provides a uniform developer layer for a long time. It is possible to obtain a high-quality copy that is formed over the entire area and has no background fog or density unevenness.

[Brief description of drawings]

FIG. 1 is a schematic view of a non-magnetic one-component developing device for obtaining setting conditions of a regulating member according to the present invention, FIG. 2 is a schematic diagram of a conventional one-component developing device, and FIG. 3 is an enlarged sectional view of the regulating member. FIG. 4 is a graph showing the relationship between the amount of wear of the regulating member and the number of copies,
FIG. 5 is a graph showing the relationship between the developer weight per unit area conveyed through the regulating member and the number of copies, and FIG. 6 is the copy density and the background fog and the number of copies corresponding to FIG. 7 is a graph showing the relationship between the developer conveyance amount and the ratio (l / t) of the free length 1 of the leaf spring material to the thickness t, and FIG. 8 corresponds to FIG. 7 is a graph showing the relationship between the density of background fog appearing in a copy and the amount of transported developer. Reference numeral 1 in the figure: 1 developer; 2 hopper; 3 …… conveying roll; 4 …… developer carrier; 5 …… regulating member; 6 …… developer layer; 7 …… leaf spring material; 8… ... Soft elastic material; 9 ... Regulator member Support on the developing machine side; 10 ...
... latent image carrier;

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Kensuke Ito 2274 Hongo, Ebina City, Ebina, Kanagawa Prefecture Fuji Zero Tsux Co., Ltd.Ebina Works (72) Inventor Junichi Hama 2274, Hongo, Ebina City, Kanagawa Fuji Zero Tux Co., Ltd.Ebina Business In-house (72) Inventor Kazuyuki Otake 2274 Hongo, Ebina-shi, Kanagawa Fuji Zero Tux Co., Ltd. Ebina Works (56) References JP-A-58-154863 (JP, A) JP-A-59-174861 (JP, A) JP-A-60-73649 (JP, A)

Claims (1)

[Claims] 1. A developer is supplied to a carrier, and a soft elastic rubber portion of a regulation member having a two-layer structure in which a soft elastic rubber body is joined to a metal leaf spring material having elasticity is brought into contact with the carrier. By doing so, a thin layer of developer is formed on the carrier and at the same time an electric charge is applied to the developer, and this developer layer is conveyed to the position opposite to the electrostatic latent image holder, and the developer is attached to the electrostatic latent image. In the one-component developing device that visualizes the above, when the length from the supporting end of the leaf spring material to the developing device side contact portion is 1 (mm) and the thickness of the leaf spring material is t (mm), l ≧ 10 In addition, the one-component developing device is characterized in that the regulating member is set so that the relation expressed by the following formula 100 ≦ l / t ≦ 500 is established.