JPH06250438A - Thermal fixing method - Google Patents

Abstract

PURPOSE:To provide a thermal fixing method by which a short wait time and high thermal efficiency are attained and sure fixation can be carried out. CONSTITUTION:A toner image is formed with a toner for developing an electrostatic charge image satisfying such characteristics as >=80 deg.C rising temp. at an endothermic peak, <=105 deg.C onset temp. in an endothermic process and 100-120 deg.C endothermic peak temp. at the time of heating on a DSC curve and 62-75 deg.C exothermic peak temp. and >=5X10<-3> intensity ratio of an exothermic peak at the time of cooling. The toner image is fixed on a transfer material by contact and heating with a fixer having <1mm thickness of the core far of a heating roll.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat fixing method for fixing an electrostatic charge image developing toner suitable for heat fixing used in electrophotography, electrostatic recording and magnetic recording by heating.

[0002]

2. Description of the Related Art Conventionally, as an electrophotographic method, U.S. Pat. No. 2,297,691 and JP-B-42-23910 are known.
Although many methods are known as described in JP-B No. 43-24748 and Japanese Patent Publication No. 43-24748, generally, a photoconductive substance is used and an electric latent image is formed on a photoreceptor by various means. And then developing the latent image with toner,
After transferring the toner image to a transfer material such as paper, if necessary,
The toner is fixed by heat, pressure, heat and pressure, or solvent vapor to obtain a copy, and the toner remaining on the photoreceptor without being transferred is cleaned by various methods, and the above steps are repeated.

In recent years, such a copying apparatus has begun to be used not only as a general-purpose copying machine for copying original documents but also as a printer as an output of a computer or a personal copy for individuals. .

[0004] Therefore, smaller size, lighter weight, higher speed, and higher reliability have been rigorously pursued, and machines have come to be composed of simpler elements in various respects. As a result, the performance required for the toner has become higher, and if the improvement in the performance of the toner cannot be achieved, a better machine cannot be established.

For example, various methods and apparatuses have been developed for fixing a toner image on a sheet such as paper.
At present, the heat fixing method is the mainstream. Among them, the heat roll fixing method using a pair of rollers is widely used because of its high thermal efficiency. Its basic configuration is as shown in FIG. That is, in the figure, 1 is a heating roller and 2 is a pressure roller. The heating roller 1 is provided with a halogen heater 1c as a heating source in the center, and an outer layer of the core metal 1b, which is an offset prevention layer formed of a resin having good releasability, as a surface layer 1
a. On the other hand, the pressure roller 2 has an elastic layer 2a on a core metal 2b. The surface temperature of the heating roller 1 is detected by the thermistor 4, and the halogen heater 1c is turned on / off so that it is in a constant temperature range.
The heating roller 1 and the pressure roller 2 are in pressure contact with each other and form a pair with an appropriate pressing portion (also called a nip portion). This roller is driven by a drive means (not shown) from the main body to rotate. The unfixed image is fixed on the transfer material by heat and pressure when the transfer material passes through the fixing guide 3 and enters the pinching portion of the pair of rollers and passes therethrough.

As described above, in the heating method via the heating roller, the toner image surface of the sheet to be fixed is passed while being in contact with the surface of the heating roller having a surface formed of a material having releasability for toner to fix the toner. Since the surface of the heating roller and the toner image on the sheet to be fixed come into contact with each other, the thermal efficiency at the time of fusing the toner image on the sheet to be fixed is extremely good, and quick fixing can be performed. , Very effective in electrophotographic copying machines.

Therefore, in order to efficiently transfer the heat of the heater to the toner, it is desirable to make the thickness of the core metal of the heating roller as thin as possible.

However, if the core metal is thin, the heat capacity of the heating roller as a whole also becomes small, and the heat is easily received from the heating roller when the sheet to be fixed passes. Therefore, the halogen heater is turned on to compensate for it. The time spent is inevitably long. During continuous paper feeding, an excessive amount of heat is supplied to the non-paper feeding portion in order to keep the temperature of the heating roller of the paper feeding portion in a constant region. Therefore, the temperature of the heating roller becomes too high, and a part of the toner image that has passed next may adhere to and transfer to the heating roller, resulting in a so-called offset phenomenon that stains the fixing target sheet.

The halogen heater is repeatedly turned on and off even when only the power source of the copying machine or the like is turned on. However, if the heat capacity is small, this halogen heater is turned on and off.
The temperature fluctuation of the heating roller due to F is large. In addition, since the temperature of the pressure roller is lowered at this time, when the sheet to be fixed passes through the fixing device when the temperature of the heating roller becomes the lowest, heat is not sufficiently transmitted to the toner,
Fixability may deteriorate.

From the above, in order to make the core metal of the heating roller thin, it is indispensable to use a toner having a non-offset and a wide fixing temperature range. However, for that purpose, it is difficult to realize without further improvement of the binder resin of the toner, the release agent and the like.

Japanese Unexamined Patent Publication (Kokai) No. 59-38772 discloses a technique of thinning the core metal of a heating roller by using a toner whose elasticity increases with time. It has not reached the offset property.

It is known to include wax as a releasing agent in the toner. For example, JP-A-52-330
4, JP-A-52-3305, JP-A-57-
Techniques such as Japanese Patent No. 52574 are disclosed.

Further, JP-A-3-50559, JP-A-2-79860, JP-A-1-109359, JP-A-62-14166, and JP-A-61-27.
3554, 61-94062, JP-A-61
-138259, JP-A-60-252361, JP-A-60-252360, and JP-A-60-2.
A technique for containing waxes is disclosed in Japanese Patent No. 17366.

Waxes are used to improve the offset resistance of the toner at low temperatures and high temperatures, and to improve the fixability at low temperatures. However, on the other hand, while improving these performances, the blocking resistance is deteriorated, the developability is deteriorated when exposed to heat due to the temperature rise of a copying machine, and the developability is deteriorated due to blooming of wax when left for a long time. It gets worse.

No conventional toner satisfies all of these aspects, and some problems have occurred. For example, high-temperature offset and developability are excellent, but low-temperature fixability is not good enough, or low-temperature offset and low-temperature fixability are excellent, but blocking resistance is slightly inferior, and developability decreases due to temperature rise inside the machine. However, there are some adverse effects, such as the fact that offset resistance at both low temperature and high temperature cannot be achieved at the same time.

In addition, low molecular weight polypropylene (for example,
Viscole 550P, 660 manufactured by Sanyo Kasei Co., Ltd.
Although a toner containing P, etc. is commercially available, a toner having improved low temperature offset property and improved fixability is desired.

[0017]

SUMMARY OF THE INVENTION An object of the present invention is to provide a heat fixing method for toner which solves the above problems.

That is, an object of the present invention is to provide a heat fixing method which has a short wait time, has a high thermal efficiency, and can perform a reliable fixing.

Further, an object of the present invention is to fix the toner at a low temperature,
It is to provide a heat fixing method having excellent offset resistance.

A further object of the present invention is to provide a heat fixing method which is excellent in offset resistance at high temperatures.

A further object of the present invention is to provide an image forming method which is excellent in blocking resistance and does not deteriorate in developability even when left for a long period of time.

A further object of the present invention is to provide an image forming method having excellent durability against temperature rise of the machine body.

A main object of the present invention is to provide a heat fixing method which can meet the above objects without contradicting each other.

[0024]

Means for Solving the Problems The present invention relates to the endotherm at the time of temperature rise in the DSC curve measured by a differential scanning calorimeter, the rising temperature at the endothermic peak is 80 ° C. or higher, and the on-state at the endothermic peak is on. The set temperature is 105 ° C or lower, and the endothermic peak temperature is 100 to 1
In the range of 20 ° C., with respect to the exothermic peak at the time of temperature decrease, the exothermic peak temperature is in the range of 62 to 75 ° C., and the exothermic peak intensity ratio is 5 × 10 ⁻³ or more, for electrostatic image development which satisfies the characteristics. The present invention relates to a heat fixing method, wherein a toner image formed of a toner is contact-heat-fixed on a transfer material by using a fixing device having a heating roller having a core metal thickness of less than 1 mm.

Further, in the present invention, in the DSC curve measured by a differential scanning calorimeter, regarding the endothermic peak at the time of temperature increase and the exothermic peak at the time of temperature decrease, the endothermic onset temperature is 5
In the range of 0 to 110 ° C., there is at least one endothermic peak P ₁ in the region of the temperature 70 to 130 ° C., there is a maximum exothermic peak at the time of cooling in the range of endothermic peak temperature ± 9 ° C. peak P ₁ , A toner image formed by a toner for developing an electrostatic image containing a hydrocarbon wax and a binder resin satisfying the characteristics is transferred by using a fixing device having a heating roller with a core metal thickness of less than 1 mm. The present invention relates to a heat fixing method, which comprises contact heat fixing to a material.

Further, the present invention will be described in detail.

In the present invention, the toner is heat-fixed to a transfer material such as plain paper or a transparent sheet for an overhead projector (OHP) by a contact heat fixing means.

In the present invention, a heating / pressurizing roll fixing device is used as the contact heating fixing means, and the core of the heating roller is particularly less than 1 mm thick. Since the thickness of the core metal is less than 1 mm, the heat of the heater is efficiently and quickly transferred to the surface of the heating roller, so the wait time can be shortened and the quick start of the first copy is possible. To do. In order to provide the heating roller with sufficient strength, it is preferable to use iron, stainless steel, carbon steel, aluminum, nickel steel, chrome steel or the like as the material of the core metal.

Further, the problem that has been caused by reducing the thickness of the core metal of the heating roller in the related art can be solved by using the toner of the present invention.

The toner of the present invention will be described in detail below.

The behavior between heat and toner can be found by analyzing the data of the toner measured by a differential scanning calorimeter. That is, it is possible to know the heat exchange with the toner and the change in the toner state from the data. For example, it is possible to know whether the offset phenomenon can be prevented, the effect of heat during storage or actual use, such as blocking resistance, and how much the temperature rise affects the developability. it can.

At the time of temperature rise, the state change when heat is applied to the toner can be seen, and the wax component is transferred, melted,
An endothermic peak associated with dissolution is observed. The present invention is characterized in that an endothermic peak rises at 80 ° C. or higher,
Excellent blocking resistance. When the temperature is lower than 80 ° C., the toner begins to change its plasticity in a range for a long time from a relatively low temperature, the storage stability is deteriorated, and the developability is apt to deteriorate with temperature rise. Furthermore, the endothermic onset temperature is 10
It is characterized by being 5 ° C. or lower (preferably in the range of 90 to 102 ° C.), which makes the low temperature fixability excellent. If it exceeds 105 ° C., the temperature of plastic change in the short-time range becomes high, and the low temperature offset resistance and fixability become poor.

The endothermic peak temperature is 100 to 120 ° C.
It is characterized by being in the range of (preferably 102 to 115 [deg.] C.), whereby good fixability and high temperature offset resistance can be obtained. If the temperature is lower than 100 ° C, the wax component is dissolved in the binder resin before the temperature rises, and it is difficult to obtain sufficient offset resistance at high temperature.
If it exceeds 120 ° C., it is difficult to obtain sufficient fixability.

That is, since the binder resin for toner used for heat fixing enters the viscoelastic region where fixing is possible from around 100 ° C., melting of the wax component in this temperature region has a plasticizing effect on the resin. It is possible to increase the fixing property, improve the fixing property, sufficiently exert the releasing effect, and improve the offset resistance. Therefore, since it does not wind around the fixing roller and does not rely on the separating claws, it does not easily cause nail marks and the like, does not stain the pressure roller, and does not wind around the pressure roller. If the above conditions are satisfied, peaks may exist in other regions.

When the temperature is lowered, changes in the state of the toner at room temperature and in the state of being cooled can be seen, and exothermic peaks due to the transition, solidification and crystallization of the wax component are observed. In the present invention, the exothermic peak temperature is 62 to 75 ° C (preferably 65 ° C).
˜72 ° C.), which provides good fixability and blocking resistance. On the other hand, 7
If it exceeds 5 ° C., the temperature range in which the wax is in a molten state is narrowed and the fixability becomes poor. If the temperature is lower than 62 ° C, blocking and fusion are likely to occur, and the plasticizing effect on the binder resin is maintained until low temperature, and the image part has a nail mark on the paper discharge part or the transfer material on the paper discharge tray. Adhesion may occur.

The peak intensity ratio is 5 × 10 ^-3 or more (preferably 10 × 10 ^-3 or more, particularly preferably 15 × 10 ^-3).
-3 or more). The larger the peak intensity ratio, the higher the density of the wax component, the higher the degree of crystallinity, the higher the hardness, the less likely to cause blocking, and the more excellent the triboelectric charging property. When it is less than 5 × 10 ⁻³ , the blocking resistance is deteriorated and the developability is affected, and the developability is particularly deteriorated when the temperature is raised, and the peak temperature is particularly low. It is easy to appear when Further, fusion on the photoconductor is likely to occur.

In the DSC measurement of the present invention, since the heat exchange of the toner is measured and its behavior is observed, it is necessary to measure with a highly accurate internal heat type input compensation type differential scanning calorimeter from the principle of measurement. For example, DSC-7 manufactured by Perkin Elmer can be used.

The measuring method is ASTM D3418-82.
Carry out according to. The DSC curve used in the present invention has a temperature rate of 10 ° C./min after the temperature is raised once and a previous history is taken.
The DSC curve measured when the temperature is lowered or raised in the temperature range of 0 to 200 ° C. is used. The definition of each temperature is defined as follows. Endothermic peak in toner (endothermic in positive direction) Rising temperature of peak in toner (LP): temperature at which the peak curve is clearly deviated from the baseline. That is, it means the temperature at which the differential value of the peak curve is positive and the increase of the differential value starts to increase, or the temperature at which the differential value changes from negative to positive. (Specific examples are shown in FIGS. 1 and 3 to 6.) Onset temperature (OP) of endotherm in toner: A tangent line of the curve is drawn at a point where the differential value of the peak curve is maximum, and a tangent line and a base line are drawn. In the toner containing the wax at the temperature of the intersection point (a specific example is shown in FIG. 1), the endothermic peak having a peak at a temperature of 70 ° C. or higher is targeted.

Temperature of endothermic peak in toner (P
P): Peak top temperature (maximum peak in the range of 120 ° C. or less.) Exothermic peak in toner (minus direction is assumed to be exothermic) Exothermic peak temperature in toner: Maximum peak peak top temperature In toner Exothermic peak intensity ratio: A tangent to each curve is drawn at the points where the differential values of the curve before and after the peak top and bottom of the peak are maximum and minimum, and the temperature difference between each tangent and the baseline intersection is ΔT, and the baseline per unit weight ΔH / ΔT (ΔH, Δ in FIGS. 2 and 7 to 10) where ΔH is the height from the peak to the peak top (value mW / mg obtained by dividing the measured peak height by the weight of the measurement sample)
A specific example of T is shown). That is, the fact that this value is large indicates that the peak is sharp.

The hydrocarbon wax used in the present invention is a low molecular weight alkylene polymer obtained by radically polymerizing alkylene under a high pressure or a Ziegler catalyst under a low pressure, or an alkylene polymer obtained by thermally decomposing a high molecular weight alkylene polymer. A hydrocarbon wax obtained by extracting and fractionating a specific component from a synthetic hydrocarbon obtained by hydrogenating a distillation residue of a hydrocarbon obtained by the Arge method from a synthesis gas composed of carbon monoxide and hydrogen is used. Hydrocarbon wax is fractionated by a press crystallization method, a solvent method, and a fractional crystallization method utilizing vacuum distillation. That is, those obtained by removing low molecular weight components, those obtained by extracting low molecular weight components, and those obtained by further removing low molecular weight components by these methods, etc.

The hydrocarbon as a base is one synthesized by the reaction of carbon monoxide and hydrogen using a metal oxide catalyst (often two or more multi-component system), for example, the gintol method, the hydrocol method ( Hydrocarbons with up to several hundred carbons (finally hydrogenated and used as the target product) obtained by the Arge method (using a fixed catalyst bed) where a large amount of waxy hydrocarbons can be obtained. Or a hydrocarbon obtained by polymerizing alkylene such as ethylene with a Ziegler catalyst is preferable because it is a saturated long-chain linear hydrocarbon with few branches and small. In particular, a hydrocarbon wax synthesized by a method that does not depend on the polymerization of alkylene is preferable because of its structure and molecular weight distribution that facilitates separation. The preferred range of the molecular weight distribution is
Number average molecular weight (Mn) is 550 to 1200, preferably 600 to 1000, and weight average molecular weight (Mw) is 800 to.
3600, preferably 900 to 3000, and Mw / Mn is 3 or less, preferably 2.5 or less, particularly preferably 2.0 or less. Further, the molecular weight is 700 to 2400 (preferably the molecular weight is 750 to 2000, and particularly preferably the molecular weight is 800).
-1600). By having such a molecular weight distribution, it is possible to give the toner favorable thermal characteristics. That is, if the molecular weight is smaller than the above range is excessively susceptible to thermal effects, blocking resistance, it becomes inferior in developability, if the molecular weight is larger than the above range, heat from the outside cannot be effectively utilized, Excellent fixability and offset resistance cannot be obtained.

As other physical properties, the density at 25 ° C. is 0.95 (g / cm ³ ) or more and the penetration is 1.5 (10 ^−1).
mm) or less, preferably 1.0 (10 ^-1 mm) or less. If it deviates from these ranges, it tends to change at low temperatures and the storage stability and developability tend to deteriorate.

The melt viscosity at 140 ° C. is 10
It is 0 cP or less, preferably 50 cP or less, and particularly preferably 20 cP or less. When the melt viscosity exceeds 100 cP, the plasticity and the releasability are deteriorated, and the excellent fixability and offset resistance are affected. The softening point is preferably 130 ° C. or lower, and particularly preferably 120 ° C. or lower. When the softening point exceeds 130 ° C., the temperature at which the releasability works particularly effectively becomes high, and the excellent offset resistance is affected.

Further, the acid value is less than 2.0 mgKOH / g, preferably less than 1.0 mgKOH / g. If it exceeds this range, the interfacial adhesion with the binder resin, which is one of the components constituting the toner, is large and the phase separation during melting tends to be insufficient, so that good releasability is difficult to obtain. Offset resistance at high temperatures is not good, and the triboelectric charging characteristics of the toner are adversely affected, which may cause problems in developability and durability.

The content of these hydrocarbon waxes is 20 parts by weight or less with respect to 100 parts by weight of the binder resin.
It is effective to use 0.5 to 10 parts by weight.

In the present invention, the molecular weight distribution of the hydrocarbon wax is determined by gel permeation chromatography (G
PC) under the following conditions.

(GPC measurement conditions) Device: GPC-150
C (Waters Co.) Column: GMH-HT 30 cm 2 series (manufactured by Tosoh Corp.) Temperature: 135 ° C. Solvent: o-dichlorobenzene (0.1% ionol added) Flow rate: 1.0 ml / min Sample: 0.15% sample 0.4 ml injection Measured under the above conditions, a molecular weight calibration curve prepared from a monodisperse polystyrene standard sample is used to calculate the molecular weight of the sample. Further, it is calculated by performing polyethylene conversion using a conversion formula derived from the Mark-Houwink viscosity formula.

The penetration of waxes in the present invention is J
It is a value measured according to IS K-2207. Specifically, it is a numerical value representing the penetration depth in units of 0.1 mm when a needle having a conical tip with a diameter of about 1 mm and an apex angle of 9 ° is penetrated with a constant load. The test conditions in the present invention are a sample temperature of 25 ° C., a load of 100 g, and a penetration time of 5 seconds.

The melt viscosity is a value measured using a Brookfield viscometer, and the conditions are a measurement temperature of 140 ° C., a shear rate of 1.32 rpm, and a sample of 10 ml.

The acid value is the number of mg of potassium hydroxide necessary to neutralize the acid groups contained in 1 g of the sample,
According to SK5902. Density is 25 ° C and JIS K6
760 and the softening point are values measured according to JIS K2207.

Further, as described above, the present invention provides a toner for developing an electrostatic charge image containing at least a binder resin and a hydrocarbon wax, wherein the hydrocarbon wax is measured by the following characteristics using a differential scanning calorimeter. In the DSC curve, the endothermic onset temperature is 5 at the endothermic peak at the time of temperature rise.
In the range of 0 to 110 ° C., at least one endothermic peak P ₁ is present and the maximum exothermic peak at the time of cooling in the range of endothermic peak temperature ± 9 ° C. peak P ₁ in the range of 70 to 130 ° C. The present invention is also achieved by a toner for developing an electrostatic charge image, characterized in that

At the time of temperature rise, a change when heat is applied to the wax can be seen, and an endothermic peak due to wax transition and melting is observed. Endothermic onset temperature is 50-11
0 ° C. (preferably 50 to 90 ° C., more preferably 6
Within the range of 0 to 90 ° C., the developability, blocking resistance and low temperature fixability can be satisfied. If the peak onset temperature is less than 50 ° C., the wax change temperature is too low, resulting in a toner having poor blocking resistance or poor developability at the time of temperature increase. Change temperature is too high, and sufficient fixability cannot be obtained. Due to the presence of an endothermic peak in the range of 70 to 130 ° C., preferably 70 to 120 ° C., more preferably 95 to 120 ° C., and particularly preferably 97 to 115 ° C., good fixing can be achieved. And offset resistance can be satisfied. When the peak temperature exists only below 70 ° C., the melting temperature of the wax is too low to obtain sufficient high temperature offset resistance, and when the peak temperature exists only in the region exceeding 130 ° C. Melting temperature is too high and sufficient low temperature offset resistance and low temperature fixability cannot be obtained. That is, the presence of the peak temperature in this region makes it easy to balance the offset resistance and the fixability. Here, when the peak below 70 ° C. becomes the maximum peak, the same behavior as in the case where there is a peak only in this region is exhibited, so a peak in this region may exist, but in that case, 70 to 130 It must be smaller than the peak in the ° C region.

When the temperature is lowered, changes in the wax during cooling and the state at room temperature can be observed, and exothermic peaks associated with the solidification, crystallization and transition of the wax are observed. The exothermic peak at the time of cooling is the maximum exothermic peak due to the solidification and crystallization of the wax. The presence of an endothermic peak due to melting at the time of temperature rise near the exothermic peak temperature indicates that the wax is more homogeneous, such as the structure and molecular weight distribution of the wax, and the difference is within 9 ° C. The temperature is preferably 7 ° C. or lower, particularly preferably 5 ° C. or lower. That is, by reducing this difference, the wax is sharply melted, that is, it is hard at low temperatures, melts quickly at melting, and the melt viscosity is greatly reduced, resulting in developability, blocking resistance, fixability, and offset resistance. Can be well-balanced and stand up. The maximum exothermic peak has a temperature of 85 to 115 ° C (preferably 90 to
110 ° C.) is preferable.

The DSC measurement of the wax is based on the case of the above-mentioned toner, and the definition of each temperature is defined as follows. Endothermic peak of wax (endothermic in the positive direction) Onset temperature of endothermic wax: The lowest temperature at which the differential value of the curve becomes maximum. Therefore, the definition is different from the onset temperature in the case of heat absorption of toner.

Wax endothermic peak temperature: peak top temperature Wax exothermic peak (minus direction is assumed to be exothermic) Wax exothermic peak temperature: maximum peak peak top temperature Content of these hydrocarbon waxes Is a binder resin 100
Used within 20 parts by weight with respect to parts by weight, 0.5-10
It is effective to use it in parts by weight and may be used in combination with other waxes as long as it does not adversely affect.

Since the toner or the hydrocarbon wax of the present invention has the above characteristics, it is possible to use a heating roller having a core metal thickness of less than 1 mm by making the best use of its characteristics. is there. That is, no offset occurs due to the temperature rise of the non-sheet passing portion when continuously feeding small size paper, and the fixability may deteriorate even when the copy interval is opened and the temperature of the lower roller is lowered. Absent. Therefore, a wide non-offset and fixing area can be obtained, and as a result, the core metal can be made thin and the sufficient fixing property and anti-offset property can be maintained, and the set temperature can be made lower than before to reduce the wait time. It has become possible to make it even shorter.

On the other hand, as the binder resin used in the toner of the present invention, the following binder resins can be used.

For example, homopolymers of styrene such as polystyrene, poly-p-chlorostyrene, polyvinyltoluene and the like, and substitution products thereof; styrene-p-chlorostyrene copolymers, styrene-vinyltoluene copolymers, styrene-vinylnaphthalene. Copolymer, styrene-acrylic acid ester copolymer, styrene-methacrylic acid ester copolymer, styrene-α-chloromethyl methacrylate copolymer, styrene-acrylonitrile copolymer, styrene-
Styrene such as vinyl methyl ether copolymer, styrene-vinyl ethyl ether copolymer, styrene-vinyl methyl ketone copolymer, styrene-butadiene copolymer, styrene-isoprene copolymer, styrene-acrylonitrile-indene copolymer -Based copolymer; polyvinyl chloride, phenol resin, natural modified phenol resin, natural resin modified maleic acid resin, acrylic resin, methacrylic resin, polyvinyl acetate, silicone resin, polyester resin, polyurethane, polyamide resin, furan resin, epoxy resin , Xylene resin, polyvinyl butyral, terpene resin, coumarone indene resin, petroleum resin and the like can be used. Preferred binder materials include styrene copolymers and polyester resins.

Examples of the comonomer for the styrene monomer of the styrene type copolymer include acrylic acid, methyl acrylate, ethyl acrylate, butyl acrylate,
Dodecyl acrylate, octyl acrylate, 2-ethylhexyl acrylate, phenyl acrylate, methacrylic acid, methyl methacrylate, ethyl methacrylate, butyl methacrylate, octyl methacrylate, octyl methacrylate, acrylonitrile, methacrylonitrile, acrylamide, etc. A monocarboxylic acid having a heavy bond or a substituted product thereof; for example, a dicarboxylic acid having a double bond such as maleic acid, butyl maleate, methyl maleate, dimethyl maleate and the like; and a substituted product thereof; for example, vinyl chloride, vinyl acetate. , Vinyl esters such as vinyl benzoate; ethylene-based olefins such as ethylene, propylene, butylene; vinyl ketones such as vinyl methyl ketone, vinyl hexyl ketone; Chirueteru, vinyl ethyl ether, vinyl ethers such as vinyl isobutyl ether; vinyl monomers are used alone or two or more.

The styrene-based polymer or styrene-based copolymer may be crosslinked or a mixed resin thereof.

As the crosslinking agent for the binder resin, a compound having two or more polymerizable double bonds may be mainly used. For example, aromatic divinyl compounds such as divinylbenzene, divinylnaphthalene; Carboxylic acid esters having two double bonds such as glycol diacrylate, ethylene glycol dimethacrylate and 1,3-butadiol dimethacrylate; divinyl compounds such as divinylaniline, divinyl ether, divinyl sulfide and divinyl sulfone; and 3
A compound having at least one vinyl group; is used alone or as a mixture.

The toner of the present invention may contain a charge control agent.

The following substances control the toner to be negatively charged.

Organic metal complexes and chelate compounds are effective, for example, monoazo metal complexes, acetylacetone metal complexes, aromatic hydroxycarboxylic acids, and aromatic dicarboxylic acid type metal complexes. Other examples include aromatic hydroxycarboxylic acids, aromatic mono- and polycarboxylic acids and their metal salts, anhydrides, esters, and phenol derivatives such as bisphenol.

There are the following substances for controlling the toner to be positively charged.

Modified products of nigrosine and fatty acid metal salts, quaternary ammonium salts such as tributylbenzylammonium-1-hydroxy-4-naphthosulfonate and tetrabutylammonium tetrafluoroborate,
And onium salts such as phosphonium salts and the like, lake pigments thereof, triphenylmethane dyes and lake pigments thereof (as the laker, phosphotungstic acid, phosphomolybdic acid, phosphotungsten molybdic acid, tannin Acid, lauric acid, gallic acid, ferricyanide, ferrocyanide, etc.) metal salt of higher fatty acid; dibutyltin oxide, dioctyltin oxide, diorganotin oxide such as dicyclohexyltin oxide; dibutyltin borate, dioctyltin borate, dicyclohexyltin borate Such as diorgano tin borate; these can be used alone or in combination of two or more kinds. Among these, charge control agents such as nigrosine and quaternary ammonium salts are particularly preferably used.

In the toner of the present invention, the charging stability,
In order to improve developability, fluidity and durability, it is preferable to add silica fine powder.

The silica fine powder used in the present invention is BE.
Specific surface area due to nitrogen adsorption measured by T method is 30 m ² / g
Those in the above range (particularly 50 to 400 m ² / g) give good results. The fine silica powder is used in an amount of 0.01 to 8 parts by weight, preferably 0.1 to 5 parts by weight, based on 100 parts by weight of the toner.

Further, the fine silica powder used in the present invention contains a silicone varnish, various modified silicone varnishes, and various other silicone varnishes for the purpose of hydrophobizing and controlling the charging property, if necessary.
It is also preferably treated with a treating agent such as silicone oil, various modified silicone oils, a silane coupling agent, a silane coupling agent having a functional group, other organosilicon compounds, or a combination of various treating agents.

As other additives, lubricant powders such as Teflon powder, zinc stearate powder and polyvinylidene fluoride powder, among others, polyvinylidene fluoride are preferable.
Alternatively, abrasives such as cerium oxide powder, silicon carbide powder, and strontium titanate powder, among which strontium titanate is preferable. Or, for example, titanium oxide powder,
A fluidity-imparting agent such as aluminum oxide powder is preferable, and a hydrophobic agent is particularly preferable. A small amount of an anti-caking agent or a conductivity-imparting agent such as carbon black powder, zinc oxide powder, antimony oxide powder, tin oxide powder, or white and black particles of opposite polarity can be used as a developing property improver.

When the toner of the present invention is used as a two-component developer, it is used as a mixture with carrier powder. In this case, the mixing ratio of the toner and the carrier powder is 0.1 to 50% by weight as the toner concentration, preferably 0.5.
10 to 10% by weight, and more preferably 3 to 10% by weight.

As the carrier that can be used in the present invention, known carriers can be used. For example, magnetic powder such as iron powder, ferrite powder, nickel powder, glass beads and the like, and the surface thereof with a fluororesin. Examples thereof include those treated with a vinyl resin, a silicone resin, or the like.

Further, the toner of the present invention may further contain a magnetic material to be used as a magnetic toner. In this case, the magnetic material can also serve as a coloring agent. In the present invention, the magnetic material contained in the magnetic toner includes iron oxides such as magnetite, hematite, and ferrite; metals such as iron, cobalt, and nickel; or aluminum, cobalt, copper, lead, magnesium, and tin of these metals. ,
Examples thereof include alloys of metals such as zinc, antimony, beryllium, bismuth, cadmium, calcium, manganese, selenium, titanium, tungsten and vanadium, and mixtures thereof.

The average particle size of these ferromagnetic materials is 2 μm or less, preferably about 0.1 to 0.5 μm. The amount contained in the toner is about 20 to 200 parts by weight, preferably 40 to 150 parts by weight, based on 100 parts by weight of the resin component.

The magnetic properties under application of 10 K oersted are as follows: coercive force ratio (Hc) 20 to 300 oersted, saturation magnetization (σs) 50 to 200 emu / g, residual magnetization (σ).
r) 2 to 20 emu / g is preferable.

The colorant that can be used in the toner of the present invention includes any appropriate pigment or dye. As the colorant of the toner, for example, carbon black as a pigment,
Examples include aniline black, acetylene black, naphthol yellow, hansa yellow, rhodamine lake, alizarin lake, red iron oxide, phthalocyanine blue, and indanthrene blue. These are used in an amount necessary and sufficient for maintaining the optical density of the fixed image, and are 0.1 to 20 parts by weight, preferably 0.2 to 10 parts by weight, relative to 100 parts by weight of the resin.
Good addition of parts by weight. Further, a dye is further used for the same purpose. For example, there are azo dyes, anthraquinone dyes, xanthene dyes, methine dyes, etc.
0.1 to 20 parts by weight, preferably 0.
The addition amount of 3 to 10 parts by weight is good.

To prepare the toner for developing an electrostatic image according to the present invention, a binder resin, a wax, a metal salt or a metal complex, a pigment as a colorant, or a dye, a magnetic substance, and if necessary, a charge control agent, Other additives and the like are sufficiently mixed by a mixer such as a Henschel mixer or a ball mill, and then melt-kneaded by using a heat kneader such as a heating roll, a kneader or an extruder to make the resins compatible with each other. The toner according to the present invention can be obtained by dispersing or dissolving a metal compound, a pigment, a dye, and a magnetic material, cooling and solidifying, and then pulverizing and classifying.

Further, if desired, desired additives can be sufficiently mixed with a mixer such as a Henschel mixer to obtain the toner for developing an electrostatic image according to the present invention.

[0079]

EXAMPLES The present invention will be described below with reference to specific examples, but the present invention is not limited thereto.

First, the hydrocarbon wax used in the present invention will be described.

Hydrocarbon wax D (comparative example) synthesized by the Arge process was used to obtain wax A (invention) and wax B (invention) by fractional crystallization.
The DSC curve of wax A (invention) at the time of temperature increase is shown in FIG. 11, and the DSC curve at the time of temperature decrease is shown in FIG.
The DSC curve at the time of temperature rise (Comparative Example) is shown in FIG. 13, and the DSC curve at the time of temperature reduction is shown in FIG. Using a Ziegler catalyst, ethylene was low-pressure polymerized to obtain a wax E (comparative example) having a relatively low molecular weight, and a wax C (invention) in which a low molecular weight component was partially removed by fractional crystallization was obtained. These physical properties are shown in Table 1, Table 2 and Table 3.

(Production Example 1) Styrene-butyl acrylate copolymer 100 parts by weight (copolymerization weight ratio = 80: 20; number average molecular weight about 10,000) Magnetic iron oxide 80 parts by weight (average particle size 0.25 μm; 10K Oersted) Under saturation magnetization 80 emu / g, remanent magnetization 10 emu / g, coercive force 120 oersted) Nigrosine 2 parts by weight Wax A 4 parts by weight After the above materials are premixed, melt kneading is performed by a twin-screw extruder set to 130 ° C. went. The kneaded product was cooled, coarsely pulverized, finely pulverized by a pulverizer using a jet stream, and further classified by an air classifier to obtain a toner 1 having a weight average particle diameter of 8 μm.

100 parts by weight of this toner is mixed with 0.6 parts by weight of positively charged hydrophobic colloidal silica fine powder (external addition).
Then, a toner having colloidal silica fine powder on the surface of the toner particles was used as a developer. The DSC measurement result of Toner 1 is shown in Table 4, and the DSC curve of Toner 1 at the time of temperature rise is shown in FIG.
2 shows the DSC curve when the temperature was lowered. The results of the blocking test are shown in Table 4. The blocking test is performed by adding about 20 g of the developer to a 100 cc poly cup at 50 ° C.
It was left to stand for 3 days and visually evaluated. In Table 4, excellent: no aggregates are seen.

Good: Aggregates can be seen, but they easily collapse.

Poor: Aggregates can be seen, but collapse if shaken.

Poor: Aggregates can be grabbed and are not easily broken. Indicates.

(Production Examples 2 to 5) Toners 2 to 5 were prepared in the same manner as in Production Example 1 except that waxes B to E were used. Table 4 shows the DSC measurement results of these toners. Table 4 shows the results of the blocking test for each toner.

Example 1 A modified machine was prepared in which the core metal of the heating roller of the electrophotographic copying machine NP-1215 (manufactured by Canon Inc.) was changed to iron having a thickness of 0.7 mm. Other fixing device configurations are shown below.

Heating roller Roller diameter 32 mm Surface layer PTFE firing Surface layer thickness 25 μm Pressure roller Roller diameter 30 mm Material (rubber layer) Silicon rubber, 5.0 mm Rubber hardness (JIS-A) 25 ° Surface layer PFA tube Surface layer thickness 50 μm Heater 900 W Nip 4.0 mm Process speed 100 mm / sec Linear pressure 0.5 Kg / cm Using the above-mentioned modified machine, the temperature setting of the fixing device was set to 180 ° C. and the wait time after power-on was measured. Furthermore,
The toner 1 obtained in Production Example 1 was evaluated for fixing property and developing property by using the modified machine as follows. The results are shown in Tables 5 and 6.

Fixing and Offset Test First, the temperature of the fixing device was set to 5 within a temperature range of 120 to 250 ° C.
The fixing start temperature, the density decrease rate at 170 ° C., the low temperature offset free starting point, and the high temperature offset free ending point were measured by adjusting the temperature at every ° C.

For the low temperature offset and fixing property tests,
80 g / m ² paper was used. For high temperature offset testing,
Evaluation was performed using 52 g / m ² paper. The fixing property is that the fixed image is applied with a load of 50 g / cm ² on sillbon paper [lenz
cleaning paper "dasper (R)"
(Ozu Paper Co. Ltd)], and the temperature at which the density reduction rate before and after rubbing was less than 10% was taken as the fixing start point. For the offset, the temperature at which the offset disappears visually was used as the low temperature offset free starting point, and the temperature was raised, and the maximum temperature without offset was taken as the high temperature offset free ending point. The test results are summarized in Table 5. Table 5 shows the fixing start temperature, the density decrease rate at 170 ° C., the low temperature offset free start point, the high temperature offset free end point, and the non-offset region.

Further, a fixing test at the start after the power was turned on, a fixing test at a copying interval, and an offset test after continuous paper feeding were performed. In the environment of a temperature of 15 ° C., the unfixed toner image was copied 20 seconds after the power was turned on while the copying machine was sufficiently cooled, and the density reduction rate before and after rubbing was measured in the same manner as in the above method. Also, immediately after the end of the wait time, 3
Copy every 2 sheets up to 200 sheets at 0 second intervals and measure the density decrease rate before and after rubbing.
The 00th sheet and the worst value were recorded. Further, immediately after 200 sheets of B5 transfer paper were continuously copied, the A3 transfer paper was copied and the offset was visually evaluated. The results are summarized in Table 6.

Developability test About 100 g of the developer was put in a 500 cc polyethylene cup and left at 45 ° C. for 3 days, and then the developability was evaluated. The results of the test (image density, fog) are shown in Table 5. By this test, it is possible to make a simulation for observing the durability against the temperature rise of the machine and the safety by leaving it for a long time.

Example 2 Using a cored bar made of 18-8 stainless steel having a thickness of 0.7 mm, a modified machine was prepared in the same manner as in Example 1, and the weight time after power-on was measured. Further, using the modified machine, the fixing property and developing property of the toner 2 obtained in Production Example 2 were evaluated. The results are shown in Tables 5 and 6.

Example 3 The weight time was measured and the fixability and developability were evaluated in the same manner as in Example 1 except that a cored bar made of iron and having a thickness of 0.8 mm was used. The results are shown in Tables 5 and 6.

Example 4 The weight time was measured and the fixability and developability were evaluated in the same manner as in Example 1 except that a cored bar made of carbon steel having a thickness of 0.7 mm was used. The results are shown in Table 5,
It shows in Table 6.

Example 5 The fixing property and the developing property were evaluated in the same manner as in Example 1 except that the toner 3 obtained in Production Example 3 was used.
The results are shown in Tables 5 and 6.

Comparative Example 1 The weight time was measured and the fixability and developability were evaluated in the same manner as in Example 1 except that a cored bar made of iron having a thickness of 1.5 mm was used. The results are shown in Tables 5 and 6.

Comparative Example 2 The weight time was measured and the fixability and developability were evaluated in the same manner as in Example 2 except that a cored bar made of aluminum having a thickness of 2.0 mm was used. The results are shown in Tables 5 and 6.

Comparative Example 3 The fixing property and the developing property were evaluated in the same manner as in Example 1 except that the toner 4 obtained in Production Example 4 was used.
The results are shown in Tables 5 and 6.

Comparative Example 4 The fixing property and the developing property were evaluated in the same manner as in Example 3 except that the toner 5 obtained in Production Example 5 was used.
The results are shown in Tables 5 and 6.

[0102]

[Table 1]

[0103]

[Table 2]

[0104]

[Table 3]

[0105]

[Table 4]

[0106]

[Table 5]

[0107]

[Table 6]

[0108]

According to the present invention, the toner containing a specific hydrocarbon wax is contact-heated and fixed on a transfer material by using a fixing device composed of a specific heating roller. Be effective.

INDUSTRIAL APPLICABILITY The present invention can provide a heating and fixing method which has a short wait time, has a high thermal efficiency, and can perform fixing reliably.

The present invention can provide a heat fixing method which is excellent in fixability at low temperature and offset resistance.

The present invention can provide a heat fixing method which is excellent in offset resistance at high temperature.

The present invention can provide an image forming method which is excellent in blocking resistance and does not deteriorate in developability even when left for a long time.

The present invention is to provide an image forming method excellent in durability against temperature rise of the machine body.

The present invention can provide a heating and fixing method that can establish the above effects without conflict.

[Brief description of drawings]

FIG. 1 is a diagram showing a DSC curve at a temperature rise of Toner 1 of the present invention.

FIG. 2 is a diagram showing a DSC curve when the temperature of Toner 1 of the present invention is lowered.

FIG. 3 is a diagram showing an endothermic peak portion of a DSC curve at the time of heating.

FIG. 4 is a diagram showing an endothermic peak portion of a DSC curve at the time of heating.

FIG. 5 is a diagram showing an endothermic peak portion of a DSC curve at the time of heating.

FIG. 6 is a diagram showing an endothermic peak portion of a DSC curve at the time of heating.

FIG. 7 is a diagram showing an exothermic peak portion of a DSC curve when the temperature is lowered.

FIG. 8 is a diagram showing an exothermic peak portion of a DSC curve when the temperature is lowered.

FIG. 9 is a diagram showing an exothermic peak portion of a DSC curve when the temperature is lowered.

FIG. 10 is a diagram showing an exothermic peak portion of a DSC curve when the temperature is lowered.

FIG. 11 is a graph of D of the wax A according to the present invention when the temperature is raised.
It is a figure which shows a SC curve.

FIG. 12 is a graph D of the wax A according to the present invention when the temperature is lowered.
It is a figure which shows a SC curve.

FIG. 13: DS of wax D (comparative example) during temperature rise
It is a figure which shows a C curve.

FIG. 14 shows DS of wax D (comparative example) at the time of cooling.
It is a figure which shows a C curve.

FIG. 15 is a diagram showing a cross-sectional view of a fixing device.

[Explanation of symbols]

 1 Heating roller 2 Pressure roller 3 Fixing guide 4 Thermistor

Claims (2)

[Claims] 1. A DSC measured by a differential scanning calorimeter.
In the curve, regarding the endotherm at the time of temperature increase, the rising temperature at the endothermic peak is 80 ° C. or higher, the onset temperature at the endothermic peak is 105 ° C. or lower, the endothermic peak temperature is in the range of 100 to 120 ° C., and the temperature is decreasing. The exothermic peak temperature is in the range of 62 to 75 ° C., and the exothermic peak intensity ratio is 5 × 10 ⁻³ or more,
A heating method characterized in that a toner image formed with a toner for developing an electrostatic charge image satisfying the characteristics is contact-heated and fixed on a transfer material by using a fixing device having a core metal of a heating roller having a thickness of less than 1 mm. Fixing method. 2. A DSC measured by a differential scanning calorimeter.
In the curve, regarding the endothermic peak at the time of temperature rise and the exothermic peak at the time of temperature decrease, the endothermic onset temperature is in the range of 50 to 110 ° C., and at least 1 in the temperature range of 70 to 130 ° C.
One of there is an endothermic peak P _1, there is a maximum exothermic peak at the time of cooling in the range of endothermic peak temperature ± 9 ° C. peak P _1,
A toner image formed with a toner for developing an electrostatic charge image containing a hydrocarbon wax and a binder resin satisfying the characteristics is transferred to a transfer material by using a fixing device in which a core of a heating roller has a thickness of less than 1 mm. A heat fixing method comprising the step of contact heat fixing to.