JPH03231757A - Two-component type toner for heat roll fixing - Google Patents

Abstract

PURPOSE:To widen a practicable fixing temp. region by regulating the viscoelastic characteristic of the toner at 150 deg.C and 200 deg.C to an adequate range. CONSTITUTION:The viscoelastic characteristic at 150 deg.C is 5X10<2 G1'<3X10<3>(dyn/cm<2>),1X10<3eta-1'<1X10<4> (poise) and G2',eta2' at 200 deg.C are so determined as to satisfy log(G1'/G2')<0.8, log(eta1'/eta2')<0.8. The G1', G2' (dynamic modulus of elasticity) and eta1', eta2' (dynamic viscosity) of the toner refer to the values measured by using 'MR3 Solikid Meter(R)' produced by Rheology Co. at the measuring frequency set at 0.1Hz. The min. fixing temp. and the temp. at which an under offset occurs are low in this way and the temp. at which a hot offset occurs is high. The practicable fixing temp. region is extremely widened.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a two-component toner for hot roll fixing, which is used for visualizing electrostatic images in electrophotography and the like.

[Conventional technology]

In an example of electrophotography, an electrostatic image is formed on a photoconductor by charging and exposure, this electrostatic image is developed with a developer containing toner to form a toner image, and this toner image is then transferred. The image is transferred to a material and fused by a heated roll fuser to form a visible image.

The two-component toner for hot roll fixing used in such electrophotography basically requires the following conditions.

(1) Excellent low-temperature fixability. In other words, the minimum fixing temperature at which toner can be fixed sufficiently for practical purposes is low.

(2) Excellent offset resistance. In other words, the temperature at which the toner transferred to the heat roll is transferred again to the transfer paper (hot offset occurrence temperature) is high, and the temperature at which the transfer paper begins to wrap around the heat roll (under offset occurrence temperature) is low. .

Toners that meet these demands have conventionally been made by chemically combining crystalline polyester with an ionically crosslinked amorphous vinyl polymer having a ratio Mw/Mn of 3.5 or more as a binder resin. A technique using bonded block copolymers or graft copolymers has been proposed (Japanese Patent Laid-Open No. 1163755).

[The problem that the invention attempts to solve]

However, upon further investigation by the present inventors, it was found that even the above-mentioned toner still may not exhibit sufficient low-temperature fixing properties and anti-offset properties.

In other words, with the above toners, even if the minimum fixing temperature is low, the hot offset occurrence temperature may be low or the under offset occurrence temperature may be high, so the practical fixing temperature range is narrow. Even when the temperature is high, the practical fixing temperature range may be narrow because the minimum fixing temperature is high or the under-offset generation temperature is high.

An object of the present invention is to provide a two-component toner for hot roll fixing that has a low minimum fixing temperature, a low under-offset occurrence temperature, a high hot offset occurrence temperature, and a wide practical fixing temperature range. be.

[Means to solve the problem]

In order to achieve the above object, the two-component toner for hot roll fixing of the present invention has viscoelastic properties at 150°C of 5 x 10''<01'< 3 x 10' (d
yn/cm2) IXIO'<η1°<IXIO'
(poise) and 02', η at 200°C
2' is log (G +' / 02°) < 0.810
A configuration that satisfies g(η,′/η,″)<0.8 is adopted.

Here, G1'' and G2° represent dynamic elastic modulus, and η1'' and η2 represent dynamic viscosity.

That is, the present invention takes into account the practical temperature conditions of the heat roll fixing device, and specifically defines the viscoelastic properties of the toner at 150°C and 200°C within an appropriate range, thereby achieving a practical fixing temperature range. This made it possible to expand the

[Effect]

In the toner of the present invention, the G1 of the toner at 150°C
' and η1' are defined within the above ranges, so even when the temperature of the heat roll of the heat roll fixing device drops to about 150°C, toner fixation failure will not occur and the toner will be fixed sufficiently firmly. become.

Since 62' and η2° of the toner at 200°C are defined in the above range, the temperature dependence of the viscoelastic properties of the toner is small, and therefore the temperature of the hot roll is 150°C.
Even when there is a large change between ℃ and 200℃, toner fixability does not deteriorate, and the under-offset generation temperature is low, so no wrapping phenomenon occurs, and the hot-offset generation temperature is high, so no offset occurs. The phenomenon does not occur.

Therefore, the practical fixing temperature range becomes sufficiently wide, and the temperature control of the thermal roll of the thermal roll fixing device can be easily controlled.

[Specific explanation of configuration]

As mentioned above, the two-component toner for hot roll fixing of the present invention has viscoelastic properties at 150°C of 5XIO2<
G+'< 3 Xl03 (dyn/cm2) 1 xl
O3<77+'< 1 xlO' (poise)
, and G, °, η2° at 200°C are log(
G, "/G2') <0.81og(η+°/η2'
)<0.8.

Here, if Glo and η1° of the toner at 150°C are smaller than the above range, the minimum fixing temperature can be lowered, but the hot offset generation temperature will also be lower; on the other hand, if they are larger than the above range, the hot offset generation temperature However, since the softening point of the toner increases, the minimum fixing temperature becomes high, and in either case, the practical fixing temperature range becomes narrow.

In the present invention, Glo, G2' (dynamic modulus of elasticity) and η1', η2' (dynamic viscosity) of the toner are defined using an MR3 solid meter manufactured by Rheology Co., Ltd. and a measurement frequency of 0.1 Hz. Refers to what has been measured.

In particular, the binder resin of the toner is a crystalline polyester, and the ratio Mw /Mn of the weight average molecular weight Mw to the number average molecule 31 Mn is 3.5 or more,
In addition, a block copolymer or a graft copolymer formed by chemically bonding an ionically crosslinked amorphous vinyl polymer (hereinafter also referred to as "ionically crosslinked amorphous vinyl polymer") is preferable. Can be used.

The ionically crosslinked amorphous vinyl polymer needs to have a functional group to form a block copolymer or graft copolymer with the crystalline polyester. Such functional groups include, for example, carboxyl group, hydroxyl group, amino group,
Preferred examples include epoxy groups.

Further, the ionically crosslinked amorphous vinyl polymer needs to be an amorphous vinyl polymer having a structure crosslinked by ionic bonds. Examples of the vinyl polymer include polystyrene, polymethyl methacrylate, polyvinyl chloride, polyvinyl acetate, polyacrylonitrile, and others. Among these, a vinyl polymer obtained using at least one selected from styrene monomers, acrylic acid monomers, and methacrylic acid monomers as an essential component is preferred.

In particular, it is preferable that a polyvalent metal compound reacts with the carboxyl group of the vinyl polymer having a carboxyl group to form an ionic crosslink. In order to obtain such a vinyl polymer having a carboxyl group, polymerization may be carried out using, in addition to the above-mentioned monomers, a monomer selected from acrylic acid or methacrylic acid and derivatives thereof as an essential component. For example, a half-ester compound having a structure obtained by an esterification reaction between an acrylic ester or methacrylic ester having a hydroxyl group, or a derivative thereof, and a dicarboxylic acid compound can be mentioned as a preferable compound.

According to such half-ester compounds, the carboxyl group is introduced at a position that has little effect on the main chain structure, so the steric hindrance of the chemical structure is reduced, and as a result, the reaction between the carboxyl group and the polyvalent metal compound becomes more efficient. The process progresses well to form ionically crosslinked bonds, and an ionically crosslinked amorphous vinyl polymer with a good crosslinked structure can be obtained.

The metal element of the polyvalent metal compound to be reacted with the carboxyl group of the vinyl polymer having a carboxyl group is as follows:
For example, Cu, Ag, Be, Mg, Ca, Sr
.

Ba, Zn, Cd, AI, Ti, Ge, S
n, V, Cr, Mo, MnFe, Ni, Co
, Zr, Se, etc.

Among these, alkaline earth metals (Be, Mg, C
a.

Sr, Ba) and zinc group elements (Zn, Cd) are preferred, with Mg and Zn being particularly preferred.

Examples of polyvalent metal compounds containing these metals include:
Fluorides, chlorides, chlorates, bromides, iodides, oxides, hydroxides, sulfides, sulfites, sulfates, selenides, tellurides, nitrides, nitrates, phosphides of the above metal elements, Examples include phosphinates, phosphates, carbonates, orthosilicates, acetates, oxalates, and lower alkyl metal compounds such as methyl compounds or ethyl compounds. Among these, acetates of the above metal elements and oxides of the above metal elements are particularly preferred.

Further, from the viewpoint of further improving low-temperature fixing properties and anti-offset properties, it is preferable that the ionically crosslinked amorphous vinyl polymer has at least two maximum values in its molecular weight distribution. Specifically, it has a molecular weight distribution divided into at least two groups: a low molecular weight component with a small maximum molecular weight value and a high molecular weight component with a large maximum molecular weight value, and has a molecular weight measured by gel permeation chromatography (GPC). In the distribution curve, at least one local maximum value is within a range of approximately 2.000 to 20.000, and at least one local maximum value is within a range of approximately 100.000 to 1.000.
It is preferable to have at least two maximum values, such as within a range of about 000. The proportion of the high molecular weight component is preferably at least 15% by weight of the ionically crosslinked amorphous vinyl polymer, particularly preferably from 15 to 50% by weight.

In addition, in the ionically crosslinked amorphous vinyl polymer, the weight average molecule is 11Mw and the number average molecule is j1MnO ratio Mw/Mn
It is preferable that the value of is 3.5 or more, especially 4 to 40
is preferred. If the value of the ratio Mw/Mn is within this range, the offset resistance will further improve. Here, the values of Mw and Mn can be obtained by various methods,
Although there are some differences depending on the measurement method, in the present invention, the value determined by the following measurement method is used.

Mw was determined by Sunawachi and Kell permeation chromatography (GPC) under the following conditions.
, Mn, measure the peak molecular weight. At a temperature of 40°C, the solvent (tetrahydrofuran) was flowed at a flow rate of 1.2 ml per minute, and the concentration was 0.2 g/20 ml! A sample solution of 3 mg of tetrahydrofuran (sample weight) is injected and measured. When measuring the molecular weight of a sample, select measurement conditions in which the molecular weight of the sample falls within a range where the logarithm of the molecular weight and the count number of the calibration curve created using several types of monodisperse polystyrene standard samples are linear. . In addition,
The reliability of the measurement results is based on NB5 measured under the above measurement conditions.
706 polystyrene standard sample (Mw-28, 8 x 10'
, 1vin=13.7 XIO'lvh /Mn
= 2.11), the value of the ratio Mw/Mn is 2.11±0.1
Confirm by checking that it becomes 0. Moreover, any column may be used as the GPC column as long as it satisfies the above conditions.

Specifically, for example, TSK-GEL, GMH (manufactured by Toyo Soda Co., Ltd.), etc. can be used. Note that the solvent and measurement temperature are not limited to the above conditions, and may be changed to appropriate conditions.

In addition, the glass transition point T of the ionically crosslinked amorphous vinyl polymer
g is preferably 50 to 100°C, particularly preferably 50 to 85°C. If Tg is within this range, fixing properties and anti-offset properties can be further improved. In the present invention, Tg is a value measured based on differential scanning calorimetry (DSC), and specifically, using DSC20 manufactured by Seiko Electronics Co., Ltd. i
When measured at n, it refers to the temperature at the intersection of the extension line of the baseline below the glass transition point and the tangent line showing the maximum slope from the rising part of the peak to the top of the peak.

Further, the softening point Tsp of the ionically crosslinked amorphous vinyl polymer is preferably 100 to 15111°C, particularly 110 to 1
40°C is preferred. If Tsp is within this range, low-temperature fixing properties will be further improved. In the present invention, the softening point Tsp
Using a flow tester rCFT500 manufactured by Shimabara Seisakusho, a 1 cm3 sample was heated at a heating rate of 6°C/min while applying a load of 20 Kg/cm2 with a plunger, and a nozzle with a diameter of 1 mm and a length of 1 mm was extruded. As a result, a plunger drop-temperature curve (softening flow curve) of the flow tester is drawn, and when the height of the S-shaped curve is h, the temperature corresponds to h/2.

The crystalline polyester that forms a block copolymer or graft copolymer with the above-mentioned ionically crosslinked amorphous vinyl polymer has a crystal structure in at least a part of the polyester, and is a homopolymer or copolymer. At least one component is crystalline, ie, partially crystallized, and exhibits a sharp and clear melting point, and in the solid state at a temperature below the melting point, it becomes cloudy due to the crystallized portion.

As such crystalline polyester, polyalkylene polyester is particularly preferred from the viewpoint of low-temperature fixability and fluidity. Specifically, for example, polyethylene sebacate, polyethylene adipate, polyethylene glycol, polyethylene succinate, polyethylene-p-(carbophenoxy) undecaate, polyhexamethylene sebacate, etc.
Polyhexamethylene sebacate, polyhexamethylene decanedioate, polyoctamethylene dodecanedioate, polynonamethylene azelate, polydecamethylene adipate, polydecamethylene acelate, polydecamethylene adipate, poly Decamethylene sebacate, polydecamethylene dodecanedioate, polydecamethylene dodecanedioate, polytetramethylene sebacate, polydecamethylene dodecanedioate, polytrimethylene octadecanedioate, polytrimethylene ester, polyhexamethylene-decamethylene-sebacate, polyoxydecamethylene-2-methyl-1,3-propane-dodecanedioate, and the like.

The melting point Tm of the crystalline polyester is preferably 50 to 120°C, particularly 50 to 100°C. If Tm is within this range, toner fixability will further improve. Note that the Tm of this crystalline polyester was measured in a state where it was not bonded to an ionically crosslinked amorphous vinyl polymer. In the present invention, Tm refers to differential scanning calorimetry (DSC>
10 mg of sample was heated at a constant heating rate (10°C/m1
n) is the melting peak value when heated.

In addition, as a crystalline polyester, its Mw is 5.0
00-50.000, Mn is 2.000-20.000
Preferably.

The proportion of crystalline polyester in the block copolymer or graft copolymer is 3 to 50% by weight, especially 5% by weight.
~411% is preferred. When the proportion of crystalline polyester is too small, low-temperature fixing properties tend to deteriorate, while when it is too large, anti-offset properties tend to deteriorate.

It is preferable that the crystalline polyester and the ionically crosslinked amorphous vinyl polymer are substantially incompatible.

Note that "substantially incompatible" means that the crystalline polyester and the ionically crosslinked amorphous vinyl polymer are not sufficiently dispersed, and specifically, for example, S, P by the Fedose method.
, value CR,F, Fedors, Polym.

Eng, Sc+, 14. (2) 147 (1
974)) is greater than 0.5.

In order to obtain a block copolymer or a graft copolymer in which a crystalline polyester and an ionically crosslinked amorphous vinyl polymer are chemically bonded, for example, they are bonded to each other in a head-to-tail manner by a coupling reaction between terminal functional groups. It can be bonded directly or via a terminal functional group and a bifunctional coupling agent. For example, a urethane bond formed by a reaction between a polymer whose terminal group is a hydroxyl group and a diisocyanate, a reaction between a polymer whose terminal group is a hydroxyl group and a dicarboxylic acid, or a reaction between a polymer whose terminal group is a carboxyl group and a glycol. ester bond formed by
The bond can be bonded by other bonds formed by reacting a polymer whose terminal group is a hydroxyl group with phosgene or dichlorodimethylsilane.

Such coupling agents include, for example, difunctional isocyanates such as hexamethylene diisocyanate, diphenylmethane diisocyanate, tolylene diisocyanate, tolidine diisocyanate, naphthylene diisocyanate, inphorone diisocyanate, xylylene diisocyanate; for example, ethylenediamine, hexamethylene Difunctional amines such as diamines and phenylenediamines;
For example, oxalic acid, succinic acid, adipic acid, sebacic acid,
Difunctional carboxylic acids such as terephthalic acid and isophthalic acid;
For example, ethylene glycol, propylene glycol, butanediol, bentanediol, hexanediol,
Difunctional alcohols such as cyclohexane dimetatool, p-quinrylene glycol; Difunctional acid chlorides such as terephthalic chloride, isophthalic chloride, adipic chloride, sebacic chloride; such as diisothiocyanate, bisketene, Other bifunctional coupling agents such as biscarbodiimide can be mentioned.

Internal additives optionally added to the toner of the present invention include colorants, wax, and the like.

Examples of colorants include carbon black, nigrosine dye, aniline blue, calco oil blue, chrome yellow, ultramarine blue DuPont oil red,
Quinoline yellow, methylene blue chloride, phthalocyanine blue malachite green offsalate, lamp black, rose benganope, mixtures thereof, and others can be used.

Waxes include low molecular weight polyolefins, fatty acid metal salts, fatty acid esters and fatty acid ester waxes, partially saponified fatty acid esters, higher fatty acids, higher alcohols, liquid or solid paraffin waxes, polyamide waxes, polyhydric alcohol esters, and silicone waxes. , aliphatic fluorocarbon, etc. can be used. Particularly preferred is a wax having a softening point of 60 to 150°C according to the ring and ball method (JIS K 2531).

External additives that may be added to the toner of the present invention as needed include fluidity improvers, cleaning performance improvers, and the like.

Examples of fluidity improvers include silica, alumina, titanium oxide, barium titanate, magnesium titanate, calcium titanate, strontium titanate, zinc oxide, silica sand, clay, mica, wollastonite, diatomaceous earth, and chromium oxide. , cerium oxide, red iron oxide, antimony trioxide,
Magnesium oxide, zirconium oxide, barium sulfate,
Fine particles of barium carbonate, barium carbonate, silicon carbide, silicon nitride, etc. can be used. Particularly preferred are silica particles.

As the cleaning property improver, for example, fatty acid metal salts such as zinc stearate, calcium stearate, and stearic acid, and polymer particles such as methyl methacrylate particles and styrene particles can be used.

In one example of the method for producing the toner of the present invention, a binder resin and internal additives added as necessary are melt-kneaded using an extruder, cooled, and then finely pulverized using a jet mill or the like, and then classified. , producing colored particles of a predetermined particle size. These colored particles may be used as they are as a toner, or if necessary, external additives may be added and mixed with the colored particles from the outside to form a toner.

The toner of the present invention is mixed with a carrier to form a two-component developer, and as such a carrier, a conventionally known carrier can be used.

The toner of the present invention is a two-component toner for hot roll fixing, and is applied to an image forming process using a hot roll fixing device. For example, in an example of electrophotography, an electrostatic charge image formed on a photoreceptor is developed with a two-component developer containing the toner of the present invention to form a toner image, and this toner image is made of paper or the like. The image is transferred to a transfer material, and then heated and fixed by a heat roll in a heat roll fixing device.

〔Example〕

Examples of the present invention will be described below along with comparative examples, but the embodiments of the present invention are not limited to these Examples. In addition, in the following, "part" represents "part by weight".

<Manufacture of crystalline polyester> (1) Crystalline polyester 1 1500 g of sebacic acid and 964 g of hexamethylene glycol were mixed with a thermometer, a stainless steel stirrer,
The reactor was placed in a round bottom flask with a capacity of 5J2 equipped with a glass nitrogen inlet tube and a flow-down condenser, and then this flask was placed in a mantle heater, and nitrogen gas was introduced through the glass nitrogen inlet tube to create an inert atmosphere inside the reactor. The temperature was raised while the temperature was maintained at .

Then, 13.2 g of p-)luenesulfonic acid was added and reacted at a temperature of 150°C. The amount of distilled water is 250-
The reaction was stopped when the temperature reached , and the reaction system was cooled to room temperature to produce crystalline polyester 1, which was made of polyhexamethylene sebacate having a hydroxyl group at the end of the molecule, and had a Tm of 64°C and a Mw of 14.000. did.

(2) Crystalline polyester 2 Made of polydecamethylene adipate in the same manner as crystalline polyester 1, with Tm of 77°C and Mw of 8.370.
A crystalline polyester 2 was produced.

<Production of amorphous vinyl polymer> (1) Place 100 parts of toluene in a separable flask containing 1 g drop of 1 p of amorphous vinyl polymer, and add 75 parts of styrene as a monomer for a high molecular weight component, 20 parts of n-butyl acrylate, 5 parts of methyl methacrylate, and 0.2 parts of benzoyl peroxide were added and dispersed, and after replacing the gas phase in the flask with nitrogen gas, the temperature was raised to 80°C. The first stage polymerization was carried out by maintaining this temperature for 15 hours. In addition, the Mw of the homopolymer of the monomer for the low molecular weight component is 461.000, T
g is 61°C.

Thereafter, the inside of the flask was cooled to a temperature of 40°C, and 85 parts of styrene and n
- 10 parts of butyl methacrylate, 5 parts of acrylic acid,
After adding 4 parts of benzoyl peroxide and continuing stirring at a temperature of 40°C for 2 hours, the temperature was raised again to 80°C and maintained at that temperature for 8 hours to carry out second stage polymerization. In addition, the Mw of the homopolymer of the monomer for the low molecular weight component is 8.2.
00, Tg is 64°C.

Next, add 0 zinc oxide, which is a polyvalent metal compound, to the flask.
15 g of the solution was added, and the reaction was carried out for 2 hours while maintaining the temperature at reflux and stirring.

After that, the reaction system is cooled to separate the solid matter, and after repeated dehydration and washing, it is dried to form an amorphous vinyl produced by reacting zinc oxide with the carbokylene groups of the vinyl polymer to form ionic crosslinks. Polymer 1 was produced. The amorphous vinyl polymer 1 has a carboxyl group as a functional group for bonding with the crystalline polyester.

This amorphous vinyl polymer 1 has two peaks in its molecular weight distribution by GPC, the peak molecular weight on the high molecular weight side is 363.000, and the peak molecular weight on the low molecular weight side is 7.000.
590, and Mw is 155. [lOL ratio Mw/Mn
The value of is 25.9, Tg is 62°C, and Tsp is 130°C.

(2) Amorphous vinyl polymer 2 In the production of the above amorphous vinyl polymer 1, 80 parts of styrene, 15 parts of n-butyl methacrylate, and 5 parts of acryloyl monosaranate were used as monomers for low molecular weight components. Amorphous vinyl polymer 2 was obtained by the same treatment except that
was manufactured. This amorphous vinyl polymer 2 has a carboquine group as a functional group for bonding with the crystalline polyester.

This amorphous vinyl polymer 2 has two peaks in its molecular weight distribution by GPC, the peak molecular weight on the high molecular weight side is 324.000, and the peak molecular weight on the low molecular weight side is 6.5.
30, MII+ is 156.000, the value of the ratio Mw /Mn is 27.0, Tg is 615°C, and Tsp is 124.0°C.

(3) Amorphous vinyl polymer 3 Amorphous vinyl polymer 3 was produced in the same manner as in the production of amorphous vinyl polymer 1 above, except that zinc oxide was not added. This amorphous vinyl polymer 3 has a carboxyl group as a functional group for bonding with the crystalline polyester.

This amorphous vinyl polymer 3 has two peaks in the molecular weight distribution by GPC, the peak molecular weight on the high molecular weight side is 355.000, and the peak molecular weight on the molecular weight side is 6.8.
40, Mw is 142.000, ratio Mw/Mn value is 24.5, Tg is 60℃, Tsp is 128.5℃
It is.

<Binder resin! l! (1) Binder resin A-I Crystalline polyester and amorphous vinyl polymer in the combinations and amounts shown in Table 1 below, 0.05 part of p-toluenesulfonic acid, and Kinren 10081: were mixed in a volume of 3β. It was placed in a separable flask and refluxed at a temperature of 150°C for 1 hour, and then the xylene was distilled off using an aspirator and a vacuum pump. Binder resin A-I was produced.

(2) Binder Resin J Amorphous vinyl polymer 1 was used as binder resin J as it was.

Table 1 (Examples and Comparative Examples) In each of the Examples and Comparative Examples, toners were manufactured as follows.

Binder resin shown in Table 2 below: 10 [) parts Carbon black 10 parts Paraffin wax 3 parts Alkylene bis fatty acid amide wax 3 parts or more of the materials are mixed, melted and kneaded with heated rolls, cooled, coarsely pulverized, and further It was pulverized using a sonic jet mill and classified using an air classifier to obtain colored particles.

To 100 parts of these colored particles, 0.8 parts of hydrophobic licorice powder was added.
1 part and 0.05 part of zinc stearate were mixed using a V-type mixer to produce each toner having an average particle size of 11.0 μm.

When the viscoelastic properties of each of the above toners were measured, the results shown in Table 2 below were obtained.

<Preparation of developer> Electrophotographic copying machine U-Bix 1550 manufactured by Konica@J
Each two-component developer having a toner concentration of 4% by weight was prepared by mixing a carrier for MR and each of the above toners.

<Evaluation> (1) Evaluation of low-temperature fixing performance Konica@-manufactured electronic device equipped with an organic photoreceptor, a developing device for two-component developer, and a hot roll fixing device, and modified to be able to variably adjust the set temperature of the hot roll. Photocopy machine U-Bix 1
With the 550MR modified machine, the linear speed of the hot roll was increased to 139m.
m/sec, and while keeping the temperature of the pressure roll lower than the set temperature of the heat roll, set the set temperature of the heat roll to 100 m/s.
A photocopy test was carried out in which a copy image was formed using each of the above two-component developers while changing the temperature stepwise in the range of ~240°C, and a constant load was applied to the edges of the resulting copy image using a rubbing tester. After rubbing, the residual rate of the image at the edge was measured using a microantometer, and the lowest set temperature (minimum fixing temperature) that provided a sufficient residual rate was determined.

The heat roll fixing device includes a heat roll with a diameter of 3Q mmO whose surface layer is made of PFA (tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer), and a heat roll whose surface layer is made of PFA (tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer).
Polycone rubber rKE-1300R coated with A
TVJ (manufactured by Shin-Etsu Chemical Co., Ltd.), the linear pressure is 0.8 kg/cm, and the nib width is 4.
．． It is 3mm thick and does not have a mechanism for applying a release agent such as silicone oil.

(2) Evaluation of under-offcent resistance Using a so-called solid black original, a live copy test was conducted in the same manner as in the evaluation of low-temperature fixing performance, while the set temperature of the heat roll was gradually lowered. The highest temperature at which under-offset occurred (temperature at which under-offset occurred) was determined.

(3) Evaluation of hot offset resistance A copy image was formed in the same manner as in the evaluation of low-temperature fixing properties above, except that the pressure roll was kept at a temperature close to the set temperature of the pressure roll, and immediately after that, a blank paper was transferred. Paper is sent to the hot roll fuser under similar conditions and visually observed to see if toner stains occur on it at each set temperature of the hot roll, and the lowest setting when toner stains occur is performed. The temperature (hot offset occurrence temperature) was determined.

(4) Evaluation of copy image quality durability Using each of the above developers, an electrophotographic copying machine U-Bix manufactured by Konica, which is equipped with an organic photoreceptor, a developing device for two-component developer, and a heating roller constant deposition device, is used. 1550MR modified machine under normal temperature and normal humidity environment conditions (temperature 20℃, relative humidity 60%)
) conducted 10,000 live-action tests,
Durability was evaluated by visually observing the obtained images. Specifically, after making continuous copies on B5 paper,
Subsequently, copies were made on A3 paper, and the quality of the images at both ends (both ends of the fixing roller) was judged. During continuous copying with B5 paper, the temperature at both ends of the fixing roller does not drop, so if you change to A3 paper and continue copying, hot offset is likely to occur at both ends of the fixing roller.

The above results are shown in Table 3 below.

In the above actual photography tests, the two-component toner of the present invention sufficiently satisfies both low-temperature fixability and offset resistance, and the practical fixing temperature range is significantly widened.

On the other hand, in comparison toner 1, the value of η1′ is too small and the value of log(η1°/η2”) is too large.
The under-offset generation temperature becomes high, and the practical fixing temperature range is narrow.

Comparative toner 2 has an excessive value of η, ", so the minimum fixing temperature is high and the practical fixing temperature range is narrow.

For comparison toner 3.4, log(c+'/G2')
Since the value of is excessive, the offset generation temperature becomes low, and the practical fixing temperature range is narrow. Further, the fluidity of the toner was also poor.

In comparison toner 5, the values of Glo and η1' are excessive, so the minimum fixing temperature is high and the practical fixing temperature range is narrow.

〔Effect of the invention〕

According to the toner of claim 1, the G1 of the toner at 150°C
' and η1'' are specified within specific ranges, and furthermore, at 200℃
Since the 62"$ and η2' of the toner in
The practical fixing temperature range becomes much wider.

According to the toner of claims 2 to 5, it is possible to further improve low-temperature fixability and offset resistance.

Claims (5)

[Claims] (1) Viscoelastic properties at 150℃ are 5×10^2<G_1′<3×10^3 (dyn/cm
^2) 1×10^3<η_1′<1×10^4(poi
se) and G_2′, η_2′ at 200°C
A two-component toner for hot roll fixing, characterized in that: log(G_1'/G_2')<0.8 log(η_1'/η_2')<0.8. (2) The binder resin contained in the toner is a crystalline polyester and an ionically crosslinked amorphous vinyl polymer having a ratio Mw/Mn of weight average molecular weight Mw to number average molecular weight Mn of 3.5 or more. The two-component toner for hot roll fixing according to claim 1, which is a block copolymer or a graft copolymer formed by chemically bonding. (3) Claim 2, wherein the ionically crosslinked amorphous vinyl polymer is formed by reacting a polyvalent metal compound with the carboxyl group of a vinyl polymer having a carboxyl group to form an ionically crosslinked bond. The two-component toner for hot roll fixing described in . (4) The functional group chemically bonded to the crystalline polyester in the ionically crosslinked amorphous vinyl polymer is a carboxyl group, a hydroxyl group, an amino group, or an epoxy group. Two-component toner for heat roll fixing. (5) The two-component system for hot roll fixing according to any one of claims 2 to 4, wherein the ionically crosslinked amorphous vinyl polymer has at least two maximum values in its molecular weight distribution. toner.