KR0138583B1 - One component toner for high speed copier - Google Patents

Abstract

The present invention is a one-component system for high-speed copiers using resins, magnetic materials, charge control agents and waxes as essential constituents when the toner is prevented from further pulverization and contamination of the sleeve during long-term copying, and is rapidly charged as well as a stable charge in the long term. It is for producing an incident toner. The resin has a shear viscosity of 1.5 × 10 ³ -3.0 × 10 ⁴ Pa · s at a shear rate of 0.1 1 s at 160 ° C., and a vertical stress coefficient of 2.0 × 10 ³ -3.0 × 10 ⁵ It has a value of Pa · s2, and the relative ratio of the vertical stress coefficient to the shear viscosity has a value between 2 and 200, and the charge control agent has a specific Q / M value at 200 and 1000 seconds, respectively. I), (II), and (III) are each composed of 0.5-2 parts by weight, 0.5-2 parts by weight, and 1.5 parts by weight or less based on 100 parts by weight of the precursor.

Description

One-component capacitive toner for high speed copier

1, 2, and 3: Behavior of Q / M (μC / g) with Time of Charge Control Agent

The present invention relates to a one-component incident charge toner for a high speed copier, and more particularly, to solve a problem of deterioration in image quality due to a change in toner particle size and charge distribution during continuous high volume copying, and a problem of fixing failure in a high speed copier. It relates to one component secondary toner.

An electrophotographic copier using a one-component toner charges fine toner particles having a size of about 10 μm through contact or friction with a sleeve / magnetic roller, and then charges the charged particles under an appropriate bias. The process of obtaining a permanent image by repeating the electrostatic latent image formed on the electrostatic force to form a toner image, moving the toner image to a medium such as paper charged higher than a drum, and then fixing it by heat and pressure. Here, the resolution and image density of the final image are almost determined in the course of development in which charged toner particles move from the sleeve to the drum in which the electrostatic latent image is formed. That is, since the latent electrostatic image formed with ions selectively takes only toner particles charged with opposite polarity, an essential condition for obtaining high resolution is to make each toner particle have a uniform and appropriate charge amount. If a large amount of toner particles of opposite polarity or excessively low or high charged amount is present, contamination of non-image parts, deterioration of image density, scattering of toner, and the like may occur. As a result, image density and image quality deteriorate. In particular, when a large amount of uncharged toner particles or toner particles having a low charge amount is present, scattering of the toner particles occurs and a problem of environmental pollution as well as a maintenance problem of the copier. From this point of view, the charge amount and charge distribution of the toner are directly related to the image quality and environmental issues, so in order to have proper charge characteristics, the electrical characteristics of the components must be considered in the design of the toner. Particle size should be determined in consideration. In particular, in the case of a toner for a high-speed copier, there is a restriction to be charged to an appropriate level within a short time, and therefore, more careful in selecting the constituent material and determining the particle size.

Several methods have been proposed to solve the problems listed above resulting from non-uniform charge distribution.

According to USP 4,299,900, USP 5,137,769 and USP 5,210,617, narrowing the particle size distribution of the particles can prevent the decrease in image density. However, according to the researches of the present inventors, the decrease in image density can be improved to some extent by narrowing the particle size distribution, but it is not a fundamental improvement, and it is particularly important to prevent the decrease in image density. Appeared to be. If the electrical characteristics of the toner particles are not uniform, even if the initial particle size distribution is narrow, only the fine particles in the developing process are preferentially developed, so that the particle size distribution of the toner particles waiting in the sleeve changes according to the repetition of the developing process. . As a result, deterioration of image density and image quality occurs as copying continues. On the other hand, USP 5,296,324 reports that the uniformity of the toner layer formed on the sleeve is affected by the particle size, the external speed, and the external time of the external substance and affects the image during long-term radiation. However, the externalization speed and externalization time set forth in USP 5,296,324 are applied to fine particles of about 8 μm, and have a long externalization time, which may lead to a decrease in transfer efficiency. In particular, in the case of a high-speed copier, the movement speed of the toner particles is high, which may cause contamination of the sleeve and the drum due to increased cohesion. According to USP 5,320,925, lubricants such as metal oxide powders can be used to prevent such contamination, but if not correctly designed, contamination of non-burned parts may occur.

Besides the problem of deterioration in image quality due to uneven charge distribution, fixing characteristics are an important consideration in designing a toner for a high speed copier. The toner particles must be melt-fixed within a short time while passing between the hot roller and the compression roller, so that the toner particles must have a low melt viscosity and a high elasticity to prevent the phenomenon of offset to the hot roller. This fixing characteristic is determined by the characteristics of the resin contained in the toner. In particular, in the case of a toner for a high-speed copier, a resin having excellent melt viscosity characteristics is required in order to increase fixability, and may include a polyester resin. However, polyester resins have the disadvantage of being expensive and inferior in triboelectric charge compared to general styrene-acrylic resins. In case of using general styrene-acrylic resins, deterioration in fixation and cold offset may occur in severe cases. Can be.

As discussed above, the long-term charging stability and fixing characteristics of the toner for a high-speed copier are typical. The triboelectric charge is greatly influenced by the grinding mechanism and the particle size distribution in addition to the electrical properties of the components. In addition, in the case of high-speed copiers, further grinding of the toner particles due to the collision of the toner and the toner or the toner and the sleeve or the blade is facilitated. Since the generated fine particles have a high charge per unit mass, they do not develop into the drum due to high electrostatic and dispersing forces and remain on the sleeve surface, thereby preventing the newly supplied toner from contacting the sleeve and consequently lowering the image density. do. On the other hand, the toner is partially melted due to the frictional heat caused by the high-speed motion, which contaminates the sleeve and hinders frictional charging.

The present inventors have solved the above problems, and as a result of earnest examination to prevent rapid toner charging and charging stability as well as to prevent pulverization of the toner during the triboelectric charging process, the present inventors have found that tribological charge is fast and three charge control agents are gentle. Dispersed in a resin with a suitable hardness along with other additives to prevent further grinding of the toner and contamination of the sleeve during long-term copying, and to invent a one-component incidental toner that maintains a stable charge over a long period of time. In order to eliminate the deterioration of fixability and the offset phenomenon which are problems of the toner for a copier, the toner of the present invention is designed such that the relative sizes of the storage modulus and the loss modulus have an appropriate size.

That is, in the present invention, in the one-component secondary toner containing resin, magnetic material, charge control agent and wax as essential components, the shear viscosity (η, shear viscosity) at a shear rate of 0.0 1 / s at 160 ° C is obtained. ^{1.5 × 10 3 - 3.0 × 10} 4 Pa · s , and the normal stress coefficient (ψ, first normal stress difference coefficient) is ^{2.0 × 10 3 - 3.0 × 10} 5 Pa · s will have the ^second value the charge control agent in 200 seconds Charge control agent (I) having a Q / M (μC / g) of 33 ± 5, 30 ± 3 at 1000 seconds, and a Q / M (μC / g) value of 20 ± 3 at 1000 seconds, at 200 seconds Charge control agent (II) having a Q / M (μC / g) value of 10 ± 3 and a Q / M (μC / g) value of 20 ± 3 at 1000 seconds and Q / M (μC / g at 200 seconds The charge control agent (I) has a value of 3 ± 2 and a charge control agent (II) having a Q / M (μC / g) value of 6 ± 2 at 1000 sec. 1 part by weight, characterized in that the charge control agent (III) is 0.5-2 parts by weight and the charge control agent (III) is 1.5 parts by weight or less. It relates to toner.

Hereinafter, the present invention will be described in detail.

The toner produced by the present invention is a one-component secondary positive toner having a resin of 30 to 90% by weight, 10 to 70% by weight of magnetic material, 0.1 to 5% by weight of charge control agent, and 0.5 to 10% by weight of wax. The present invention includes not only one-component secondary toner, but also its field of application includes one-component positively-charged toner and two-component toner.

The resin, which occupies the main component of the toner, should be free from pulverization during triboelectric charging, and should have sufficient elastic strength as well as low melt viscosity for rapid fixing.

The resin applicable to the present invention has a shear viscosity (η, shear viscosity) at 160 ° C. and a shear rate of 0.1 1 / s of 1.5 × 10 ³ -3.0 × 10 ⁴ Pa · s, and a vertical stress coefficient (ψ, The first normal stress differene coefficient should be between 2.0 × 10 ³ and 3.0 × 10 ⁵ Pa · s ² . If η exceeds 3.0 × 10 ⁴ , the fixability decreases, while if η is less than 1.5 × 10 ^{3, an} offset and blocking phenomenon occurs. If ψ exceeds 3.0 × 10 ⁵ , a cold offset occurs, and if less than 2.0 × 10 ³ , further pulverization occurs during triboelectric charging and external addition. The relative ratio of ψ to η should be between 2 and 200 in order to eliminate the hot offset phenomenon that often occurs during high temperature fixing process. In order to satisfy the above conditions, a resin having a molecular weight distribution of bimodal molecular weght distribution or branched structure or gel is preferred. Since the high molecular weight portion, the branch structure or the gel increases the elasticity, it serves to prevent further pulverization and offset phenomenon during the triboelectric charging process, and the low molecular weight portion increases the fixability. Representative resins are polyesters, polyamides, polyurethanes, epoxies, and vinyl resins. Vinyl resins are polystyrene, poly-α-methylstyrene, polychlorostyrene, polyvinyl naphthalene, polyethylene, polypropylene, polyisobutylene, polyvinyl chloride, polyvinyl fluoride, polyvinylacetate, polymethylacrylate, polyethylacryl Latex, polybutyl acrylate, polyisobutyl acrylate, polydodecyl acrylate, polyoctyl acrylate, polyphenyl acrylate, polyvinyl ethyl ether, styrene butadiene copolymer, styrene butyl acrylate copolymer, styrene ethylhexyl acryl Acrylate copolymers, and styrene butyl methacrylate copolymers.

The charge control agent plays the most important role in determining the charge amount and the charge distribution of the toner particles. The negatively charged charge control agents used in the present invention are three (I, II, III) having the behavior as shown in Figs. 1, 2 and 3, respectively, for rapid charging, long-term stability, and reverse polarity. It serves to prevent the formation of toner and is appropriately mixed. When used separately, degradation of long-term stability, initial image defects, and low image density due to low charge amount are caused, respectively. When the charge control agent is described in detail, the charge control agent (I) has a Q / M (μC / g) value of 33 ± 5 at 200 seconds (sec) and at 1000 seconds (sec) as shown in FIG. It has a Q / M (μC / g) value of 30 ± 5. As shown in FIG. 2, the charge control agent (II) has a Q / M (μC / g) value of 10 ± 3 at 200 seconds (sec) and a Q / M of 20 ± 3 at 1000 seconds (sec). μC / g). As shown in FIG. 3, the charge control agent (III) has a Q / M (μC / g) value of 3 ± 2 at 200 seconds (sec) and a Q / M of 6 ± 2 at 1000 seconds (sec). μC / g). Materials usable as charge control agent (I) include metal complexes of mono azo dyes, for example, complexes containing chromium, nickel, cobalt and iron and the like. As a substance which can be used as a charge control agent (II), the substance of the form which substituted the metal complex of a mono azo dye type, or the terminal group by an auxiliary substance, such as chlorine type, is preferable. Examples of the materials that can be used as the charge control agent (III) include ancillary materials that do not contain a metal, such as a benzoic acid compound, an acetic acid compound, a sulfuric acid compound, and a resin charge control agent such as isocarcinogenic FCA-1001-N. , FCA-1001-NB and FCA-1001-NZ and the like are preferred. The amount of charge control agents (I), (II) and (III) used was 0.5-2 parts by weight of charge control agent (I) and 0.5-2 parts by weight of charge control agent (II) based on 100 parts by weight of the total composition. 1.5 parts by weight or less of the charge control agent (III) is used.

Magnetic materials used in the present invention include metals such as iron, cobalt, nickel and alloys thereof, metal oxides such as Fe ₃ , O ₄ , γ-Fe ₂ O ₃ , and cobalt-added iron oxides, Mn.Zn ferrite, Ni.Zn. Ferrite, magnetite, hematite and the like are used. The particle diameter of these magnetic bodies is good to be 0.05-0.5 micrometer. Magnetic material should have characteristics of coercive force of 20 ~ 2000e, saturated magnetic force of 30 ~ 300 emu / g, residual magnetic force of 1 ~ 30 emu / g. In order to improve the frictional chargeability, a magnetic material having a particle size of 0.05 to 0.1 μm may be used, and a low particle distribution is preferable.

The toner of the present invention contains polyethylene or polypropylene wax having a molecular weight of 1,000 to 10,000 in the range of 0.5 to 10% by weight in order to prevent the offset phenomenon during the high temperature fixing process.

The toner of the present invention contains internally or externally added silica to increase flowability, and positively charged and secondaryly charged silica, alumina, and other conductive metal oxide powders are mixed to maintain stable triboelectric charge. The external attachment is made by mixing the classified toner particles and the external additive at 0.5 to 10 minutes at a linear speed of 5 to 60 m / s. The triboelectric charge characteristics of the toner vary greatly depending on the state in which the external additive is attached to the toner surface. Therefore, in order to maintain stable triboelectric charge characteristics, it is more effective to separate the external additives and coat them in the order of 0.1 to 2.0% by weight relative to the toner. . In particular, in order to maintain uniform triboelectric charge characteristics and an appropriate triboelectric charge amount, metal oxide powder having a BET area of 10 to 200 m ² / g and a conductivity of 10 to 200 l · cm and a hydrophobic positively charged silica or alumina having a BET area of 50 to 400 m ² / g Is recommended to use 0.1 to 2.0% by weight of the toner. Silica or alumina is preferably surface treated with positively and hydrophobic materials, and a mixture of ancillary silica or alumina may be used for the purpose of obtaining proper frictional chargeability. The toner according to the present invention may be used in combination with other ingredients, if necessary. For example, a charge control agent, an electrical resistance agent, a coloring agent, etc. can also be added according to wood. That is, for example, a fluorine-based surfactant, a metal salicylate with a salicylic acid chromium complex, a quaternary dye such as quaternary ammonium salt, nigrosine dye, carbon black, and the like can be added. In addition, inorganic fine powders such as silica, organic fine powders such as fatty acids or derivatives thereof and metal salts, fine fluorine resin powders and the like can be added for the purpose of improving the durability, fluidity and cleaning properties of the toner.

When described in detail through an embodiment of the present invention.

Example 1

Example 2

Example 3

Each of the components of Examples 1, 2, and 3 was subjected to powder mixing, and then melt mixed at 150 ° C. using a Buss Kneader. After cooling, a fine powder having a size of an average particle diameter of 13 μm was prepared through coarsely pulverized and classified processes. 1.0% of 10 μm fine silica powder was added to the prepared powder, followed by external addition for 5 minutes at a linear speed of 30 m / s. The prepared toner was applied to a copy of 200,000 sheets using a Kennon NP6640 copier. The initial image density was 1.30 or more and the image density was maintained at 1.30 or more after 200,000 copies. No fouling phenomenon or scattering phenomenon was observed in the non-image area. Hot and cold offset phenomena were not observed in the fixation process and fixation was excellent.

Comparative Example 1

Toner was prepared by the procedure of Example 1 using the above components and subjected to a copy test. The image density was high as 1.45, but the wave phenomenon occurred deeply. Fixability was relatively poor.

Comparative Example 2

The components of Comparative Example 2 were prepared by Tonal through the procedure of Example 1 and carried out copying. The initial image density was good as 1.30, but the image density decreased to 1.20 at 10,000 sheets, and the wave and sleeve contamination and hot offset occurred, and the blocking result was observed at 30 ° C.

Comparative Example 3

Toner was prepared by copying the components of Comparative Example 3 through the procedure of Example 1. Initial image density was low as 1.25 and gradually resisted. Cold offset phenomenon was observed and fixability was poor.

Example 4

Example 5

The toner was prepared by copying through the procedure of Example 1 using the components of Example 4 and Example 5. As a result of 200,000 copies, an image density of 1.30 or more was maintained, and cold offset and poor fixability were not observed.

[Comparative Example 4]

Toner was prepared through the procedure of Example 1 using the components of Comparative Example 4 to conduct a copy test. The image density was as high as 1.35 or more, but wave phenomenon was observed after 500 sheets, and toner adhered to the sleeve.

[Comparative Example 5]

A copy test was conducted after the toner was prepared using the components of Comparative Example 5. From the beginning, the image density was very low as 1.00 or less.

Comparative Example 6

The constituents of Comparative Example 6 were prepared and a toner was prepared and then subjected to a copy test. The initial image density was low, below 1.00, and tended to increase gradually.

Comparative Example 7

A toner was prepared and subjected to a copy test using the components of Comparative Example 7. The initial image density was good as 1.35 or more, but dropped to 1.30 or less as a result of 10,000 copies. The image test results of Examples and Comparative Examples were compared in Table 1.

Claims (5)

In a one-component auxiliary electroconductive toner for a high speed copying machine comprising a resin, a magnetic substance, a charge control agent and a wax as essential components, the resin has a shear viscosity (η, shear viscosity) of 1.5 at a shear rate of 0.1 1 / s at 160 ° C. ^{× 10 3 - 3.0 × 10 4} Pa · s , and the normal stress coefficient (ψ, first normal stress difference coefficient) is 2.0 × 10 ³ - has a 3.0 × 10 ⁵ Pa · s ² values, for the shear viscosity (η) The relative ratio of the vertical stress coefficient (ψ) has a value between 2 and 200, and the charge control agent has a Q / M (μC / g) of 33 ± 5 at 200 seconds and a Q / of 30 ± 5 at 1000 seconds. Charge control agent (I) with M (μC / g) and Q / M (μC / g) is 10 ± 3 at 200 seconds and 20 ± 3 Q / M (μC / g) at 1000 seconds. Charge control agent (II) having a charge control agent (III) having a Q / M (μC / g) of 3 ± 2 at 200 seconds and a Q / M (μC / g) value of 6 ± 2 at 1000 seconds. The charge control agent (I) is 0.5-2 parts by weight, the charge control agent (II) is 0.5-2 parts by weight and the charge control agent (III) is 1.5 parts by weight High-speed copiers 1-component chargeable toner featuring configured as follows. The one-component secondary electroconductive toner for high-speed copier according to claim 1, wherein the resin is polyester, polyamide, polyurethane, epoxy, or vinyl resin. The vinyl resin of claim 2, wherein the vinyl resin is polystyrene, poly-α-methylstyrene, polychlorostyrene, polyvinyl naphthalene, polyethylene, polypropylene, polyisobutylene, polyvinyl chloride, polyvinyl fluoride, polyvinylacetate, polymethyl Acrylate, polyethyl acrylate, polybutyl acrylate, polyisobutyl acrylate, polydodecyl acrylate, polyoctyl acrylate, polyphenyl acrylate, polyvinyl ethyl ether, styrene butadiene copolymer, styrene butyl acrylate A one-component secondary electroconductive toner for a high speed copying machine, characterized in that it is a copolymer, a styrene ethylhexyl acrylate copolymer, and a styrene butyl methacrylate copolymer. 2. The form according to claim 1, wherein the metal complexes of mono azo dyes as the charge control agent (I) and the metal complexes or terminal groups of the mono azo dye type as the charge control agent (II) are replaced with an auxiliary material such as chlorine. The one-component incident charge toner for a high-speed copier according to claim 1, wherein the charge control agent (III) uses a benzoic acid compound, an acetic acid compound, a sulfuric acid compound, and a resin-based acid control agent. The toner is a one-component bag for a high-speed copier according to claim 1, wherein the toner is composed of 30 to 90% by weight of resin, 10 to 70% by weight of magnetic material, 0.1 to 5% by weight of charge control agent, and 0.5 to 10% by weight of wax. Malleable toner.