JP3383765B2 - Non-magnetic one-component developing toner - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a toner used in an image output device such as a copying machine or a printer.

[0002]

2. Description of the Related Art In a non-magnetic one-component developing method, toner is carried on the surface of the carrying member by the electrostatic force of the toner and the carrying member, and the toner is carried to a developing position to develop the latent image on the surface of the photoreceptor. In order to generate an electrostatic force between the toner and the conveying member, a layer thickness regulating member that is in contact with the conveying member is often used, and when the toner passes between the layer thickness regulating member and the conveying member, the toner Will be charged. Further, in order to charge the toner instantly and uniformly, it is important to make the toner thin, and the member also regulates the toner layer at the same time. Therefore, when the conveying member and the layer thickness regulating member are contaminated with the toner, the toner on the conveying member cannot be controlled to a desired charge amount, resulting in increased fog and white stripe-like density unevenness.

Conventionally, it has been proposed to increase the amount of externally added silica in order to reduce toner contamination. This aims at preventing fusion of the toner component due to frictional heat generated when the toner passes between the transport member and the layer thickness regulating member, but cannot sufficiently prevent toner contamination.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to provide a negatively chargeable non-magnetic material 1 capable of providing a high-quality image even when it is repeatedly used without toner contamination on the conveying member and the layer thickness regulating member.
A toner for component development is provided.

[0005]

The present invention relates to a developing device having at least a carrying member carrying and carrying a non-magnetic one-component developing toner, and a layer thickness regulating member provided in pressure contact with the carrying member. The toner used is a positively chargeable silica and a negatively chargeable silica that are at least hydrophobized on the surface of a resin powder containing a binder resin, a colorant, and a negatively chargeable charge control agent as essential components. By attaching
Toner fusion to the conveying member and the layer thickness regulating member should be prevented. When the addition amounts of the positively chargeable silica and the negatively chargeable silica are Wp and Wn, respectively, and the absolute values of their saturated charge amounts are | Qp | and | Qn |, the following formula (1) is satisfied. By using the silica external addition method, a conveying member,
It was found that an image having high image density and less fog can be obtained without toner fusion on the layer thickness regulating member.

[0006]

[Equation 2] However, Wn is 0.5 to 0.9 parts by weight and Wp is 0.02.
5 to 0.20 parts by weight.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below.
As the binder resin used in the toner of the present invention, an alcohol component such as a dialcohol component, a polyester resin obtained from a polyhydric alcohol component and a carboxylic acid component such as a dicarboxylic acid component or a polyvalent carboxylic acid component, or a part thereof A polyester resin such as a polyester resin having a urethane bond, or a thermoplastic resin such as a styrene-acrylic copolymer known as a binder for a conventional non-magnetic one-component toner is used. From the viewpoint of storage stability of the toner, these binder resins are preferably binder resins having a glass transition point of 55 ° C. or higher, and the acid value thereof is preferably 40 or lower. If the acid value exceeds 40, the moisture resistance deteriorates, which is not preferable. It is more preferably 20 or less.

The colorants used in the toners of the present invention include any suitable pigment or dye conventionally used in toners. Carbon black as a pigment,
Examples include aniline black, acetylene black, naphthol yellow, Hansa yellow, rhodamine lake, alizarin lake, red iron oxide, phthalocyanine blue, indanthrene blue and the like. These pigments are used in an amount necessary and sufficient for maintaining the optical density of a fixed image, and usually 0.1 to 20 parts by weight, preferably 0.2 to 10 parts by weight is added to 100 parts by weight of the binder resin. It As a dye
Azo dyes, anthraquinone dyes, xanthene dyes, methine dyes and the like are exemplified. These dyes are usually added in an amount of 0.1 to 20 parts by weight, preferably 0.3 to 10 parts by weight, based on 100 parts by weight of the binder resin.

As the negatively chargeable charge control agent, for example, an organic metal complex or a chelate compound is effective, and an azo metal complex, an acetylacetone metal complex, an aromatic hydroxycarboxylic acid, an aromatic dicarboxylic acid, an aromatic monocarboxylic acid or a poly (polycarboxylic acid) is used. Examples thereof include carboxylic acids and their metal salts, anhydrides, esters, and phenol derivatives such as bisphenol.
These charge control agents are usually added in an amount of 0.1 to 10 parts by weight, preferably 0.5 to 5 parts by weight, based on 100 parts by weight of the binder resin. If it exceeds the upper limit of the above range, image quality is deteriorated due to fog and the like, and if it is less than the lower limit, a sufficient charge amount cannot be obtained, and the image density is lowered,
There is a problem that the image density is not stable when a large number of sheets are continuously copied. Further, the resin powder may contain a release agent such as polypropylene wax or polyethylene wax.

The resin powder may be obtained by melt-kneading, pulverizing and classifying the above-mentioned binder resin, colorant, negatively chargeable charge control agent and the like. Alternatively, when the binder resin is polymerized, the colorant and negatively chargeable charge control may be carried out. It may be obtained by a polymerization method in which an agent or the like is contained. The positively chargeable silica and the negatively chargeable silica described below can be adhered to the surface of the resin powder by using a stirrer such as a Henschel mixer or a super mixer. The positively chargeable silica and the negatively chargeable silica are resin powders. It may be attached to the surface of the resin in a weak state called glaze, or a part of the positively chargeable silica and the negatively chargeable silica may be embedded and fixed inside the resin powder. In addition to the positively chargeable silica and the negatively chargeable silica, inorganic oxides such as alumina, titania and zinc oxide, and conductive fine particles such as carbon black may be attached to the surface of the resin particles.

As the hydrophobized negatively-charged silica and positively-charged silica used in the present invention, commercially available ones can be used, but it is a relational expression between the saturated charge amount and the adhesion amount on the toner surface (1 ) It is necessary to select silica that satisfies the formula and determine the amount thereof in order to obtain an image with high image density and less fog. Value of the central term of the formula (1) Wn × | Qn | / Wp × | Qp |
When the value is less than 7, the fog increases, and when it is more than 30, the toner is likely to be fused to the conveying member (hereinafter referred to as a sleeve) and the layer thickness regulating member (hereinafter referred to as a blade). In addition, the amount of the positively chargeable silica attached is 100
It is necessary that the amount is 0.025 parts by weight or more with respect to parts by weight, and if it is less than 0.025 parts by weight, the toner fusion preventing effect cannot be recognized. The upper limit is 0.20 parts by weight or less
It The amount of the negatively chargeable silica may be determined in consideration of the fluidity of the toner, but 0.5 to 0.9 parts by weight is required.
is there.

Although the reason why toner fusion does not occur when negatively chargeable silica and positively chargeable silica are used in combination within the scope of the present invention has not been completely clarified, the charging polarity of the sleeve and the blade is different from that of the toner. Since the polarity is opposite to the normal charging polarity (negative charging in the case of the present invention), the toner to which only the negatively charging silica is attached is likely to be firmly attached to the blade or the sleeve, and the toner is likely to be attached between the blade and the sleeve. It is considered that the frictional force at the time of passage increases, resulting in toner fusion.

However, when the positively chargeable silica is added within the range of the present invention, a part of the toner surface that is neutrally or positively charged is generated, and this part exerts a roller action, thereby making the toner. It is considered that the above-mentioned frictional force applied is weakened, as a result of which toner fusing is prevented and an extreme amount of positive charge is not generated, so that the toner is less likely to cause fog, density usability, and toner scattering.

[0014] As the negatively chargeable silica, hydrophilic silica hexamethylene Le disilazane, silane compounds such as dimethyldichlorosilane, dimethyl silicone oil, the various modified silicone oils those known in which a hydrophobic treatment is available. As the positively chargeable silica, known ones obtained by subjecting hydrophobic silica to hydrophobic modification and positive charge imparting treatment with various silane compounds together with amino-modified silicone oil, quaternary ammonium compound, etc. It is possible.

The positively chargeable and negatively chargeable silicas having a primary average diameter of about 10 to 50 nm can be preferably used because they have a high toner fluidity imparting effect, and a methanol wettability value of 40 or more as a measure of hydrophobicity. preferable.
More preferably, it is 45 or more. If it is less than 40, the toner charge in the high temperature environment is greatly reduced, which is not preferable.

The optimum total addition amount of the positively chargeable silica and the negatively chargeable silica cannot be determined unconditionally depending on the particle size distribution of the toner and the fluidity of the resin powder before the addition of silica, but for example, the volume average diameter 8 In the case of a toner having a particle size of ˜9 μm, 0.2 to 2 parts by weight is preferable for 100 parts by weight of the resin powder. It is more preferably 0.4 to 1.5 parts by weight. If it exceeds 2 parts by weight, environmental stability and fixing property are likely to be deteriorated, which is not preferable.

A method for measuring the saturated charge amounts Qpμc / g and Qnμc / g of the positively and negatively charged silica will be described. The positively-charged or negatively-charged silica is sieved with a 150-mesh sieve, and the silica that has passed 150 mesh is used for the measurement. Carrier (made by Powder Tech: FSL
1020) 99.8 g and 0.2 g of measuring silica 150
Put in cc polybin, 22-24 ℃ / 57-62% R
Leave in an atmosphere adjusted to H for 10 hours. After that, the polybin is placed on a rotating device of constant rotation, and then the polybin is rotated and mixed and stirred under this atmosphere. In the mixing process, the charge amount of silica is measured with a blow-off charge amount measuring device three times every 5 minutes from the initial stage, and the average value of the three times is rounded to the nearest whole number to obtain the charge amount in the stirring time. .
Since the charge amount of silica becomes maximum at a certain point in time series and decreases thereafter, the maximum charge amount in the stirring and mixing process is defined as the saturated charge amount in the present invention. A 400-mesh stainless mesh is used for separating the carrier and silica when measuring with a blow-off charge amount measuring device.

[0018]

EXAMPLES Examples will be shown below, but the present invention is not limited thereto.

<Production of Resin Powder A> Polyester resin (Tg = 63 ° C., Mn = 3900, Mw = 48300, THF insoluble matter = 13%) 100 parts by weight carbon black (Cabot Corporation: Legal 400R) 5.5 parts by weight Part Negatively chargeable charge control agent (Orient Chemical Co., Ltd .: S-34) 1.3 parts by weight Polypropylene wax 1.5 parts by weight (Sanyo Kasei Co., Ltd .: Viscole 550P) Extruder after uniformly mixing the above materials Kneaded thoroughly. After cooling, pulverizing and classifying, volume average diameter 9.5 μm
Resin powder A of was obtained.

<Example of Negatively Charged Hydrophobic Silica> 1. Silica A (methanol wettability value = 48, dimethyldichlorosilane treatment, specific surface area 110 m ² / g) Saturated charge amount Qn = −320 μc / g 2. Silica B (methanol wettability value = 80, hexamethyi
Le disilazane treatment, a specific surface area of 140 m ² / g) saturated charge amount Qn = -490μc / g

<Example of Positively Charged Hydrophobic Silica> Saturated charge amount Qp 1. Silica C (HVK2115 manufactured by Clariant Japan KK) +130 μc / g 2. Silica D (manufactured by Clariant Japan: H3050EP) +380 μc / g As shown in Table 1, silica was adhered to the above resin powder A by a Henschel mixer to prepare toners of Examples and Comparative Examples, and commercially available non-magnetic one-component developing printer (20PPM ), A print test is performed, and image density (ID) and fog (B
G), the presence or absence of toner fusion was confirmed. The test environment conditions are 22 to 25 ° C./55 to 65% RH. In the print test, a character chart with a printing rate of about 6% was repeatedly printed. The presence or absence of toner fusion was confirmed by printing a halftone image (A4 size). The results of the live-action test are shown in Table 2. The image density (ID) is the reflection density of a solid image measured by Macbeth RD-914, and the fog (BG) is the difference in hunter whiteness of the non-image area between the paper before printing and the paper after printing. Show.

[0022]

[Table 1]

[0023]

[Table 2]

[0024]

As is clear from the results of the above comparative examination, the toner of the present invention is subjected to a hydrophobic treatment on the surface of a resin powder containing a binder resin, a colorant and a negatively chargeable charge control agent as essential components. By attaching the positive and negative chargeable silica, a preferable charge amount can be obtained, and in particular, 7 ≦ Wn × | Qn
The toner for one-component development, which is set such that | / Wp × | Qp | ≦ 30, is obtained even after the actual copying test after 7,000 sheets.
Adhesion of toner to the sleeve was not observed, which was preferable.

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Atsushi Miyamoto 3-1, Somune-cho, Shizuoka-shi, Shizuoka Prefecture Stock company, Tomoegawa Paper Co., Ltd. (56) Reference JP 62-17751 (JP, A) JP 61-250658 (JP, A) JP 9-171267 (JP, A) JP 9-166884 (JP, A) JP 9-160297 (JP, A) JP 9 -114128 (JP, A) JP 8-234479 (JP, A) JP 7-36209 (JP, A) JP 6-83103 (JP, A) JP 4-260061 (JP, A) ) JP-A-2-298959 (JP, A) JP-A-2-66564 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G03G 9/08

Claims (2)

(57) [Claims] 1. A surface of a resin powder containing a binder resin, a colorant, and a negatively chargeable charge control agent as essential components, on the surface of which at least hydrophobically-treated positively-charged silica and hydrophobically-treated negatively-charged silica are provided. The adhesion amount of the positively chargeable silica is Wp parts by weight and the saturation charge amount is Qpμc / g, and the adhesion amount of the negatively chargeable silica is Wn parts by weight and the saturation charge amount relative to 100 parts by weight of the resin powder. A toner for non-magnetic one-component development, which satisfies the following expression (1) when Qn μc / g. [Equation 1] However, Wn is 0.5 to 0.9 parts by weight and Wp is 0.02.
5 to 0.20 parts by weight. 2. The non-magnetic one-component developing toner according to claim 1, wherein the positively chargeable silica and the negatively chargeable silica have a methanol wettability value of 40 or more.