JPH03111856A - Heat fixing method and toner for heat fixing - Google Patents

Abstract

PURPOSE:To shorten the wait time in heat fixing and to reduce electric power consumption as well as to prevent offsetting by supporting a developed image formed by the specific suspension polymerized toner on a recording material and bringing the images into adherence with a heating body via a film. CONSTITUTION:The suspension polymerized toner formed by suspending a monomer compsn. in the toner grains in an aq. medium and polymerizing the same is used in the heat fixing method. Polyolefin which has 1 to 250cps melt viscosity at 160 deg.C and is graft denaturalized with an arom. vinyl monomer (e.g.: styrene) and unsatd. fatty acid (ester) (e.g.: ethyl acrylate) is incorporated at 0.1 to 20wt.% into the toner. The sensible images 20 formed by the toner are disposed to face the heating body 11 formed and fixed onto the recording material 19 and are brought into adherence therewith via the film 15 (e.g.: a polyimide film provided with a releasing layer formed by adding a conductive material to PTFE on the surface in contact with the material 19), by which the images are thermally fixed.

Description

Detailed Description of the Invention [Industrial Application Field] The present invention relates to a fixing method for fixing a visual image formed with toner in electrophotography, electrostatic printing, magnetic recording, etc. to a recording material, and a fixing method used in the fixing method. related to toner.

[Prior Art] Conventionally, a method for fixing a toner image on a recording material involves using a heating roller maintained at a predetermined temperature and a pressure roller having an elastic layer that presses against the heating roller.
A hot roll fixing method is often used in which a recording material holding an unfixed toner image is heated while being nipped and conveyed.

Furthermore, a belt fixing method described in tlsP No. 3,578,797 is known.

[Problems to be Solved by the Invention] However, in the above-mentioned hot roll fixing which has been frequently used in the past, (1) there is a so-called wait time, which is a period during which the image forming operation is prohibited until the hot roller reaches a predetermined temperature.

(2) Set the heating roller to the optimum temperature in order to prevent fixing failure and toner transfer to the heating roller due to fluctuations in the temperature of the heating roller due to passage of the recording material or other external factors. For this purpose, the heat capacity of the heating roller or heating body must be increased, which requires a large amount of electric power and also causes an increase in temperature inside the image forming apparatus.

(3) Since the roller is at a constant temperature, when the recording material passes through the heating roller and is discharged, the recording material and the toner on the recording material are slowly cooled, resulting in a highly sticky state and the roller Coupled with the curvature of the recording material, paper jams may occur due to offset or entrainment of the recording material.

(4) The high-temperature heating roller is directly touched by the hands, which may pose a safety problem or require a protective member.

Also, in the belt fixing method described in USP 3,578,797, the above-mentioned problem (1) of heat roll fixing, (
2) has not been fundamentally resolved.

In the applicant's previous proposal, the wait time is shortened by a fixing device that heats the toner image via a moving heat-resistant sheet using a low-heat-capacity heating element that generates electricity in a pulsed manner and fixes it onto the recording material. Image forming apparatuses with low power consumption have been proposed. Similarly, in a previous proposal by the present applicant, in a fixing device that heats and fixes a toner image to a recording material via a heat-resistant sheet, the heat-resistant sheet has a heat-resistant layer and a release layer or a low-resistance layer. A fixing device that has a layer to effectively prevent the offset phenomenon has been proposed.

However, in order to realize a fixing method that achieves excellent fixation of toner images on recording materials, prevents offset, etc., and has a short wait time and low power consumption, it is necessary to use in addition to the above-mentioned fixing device. This is largely due to the characteristics of the toner.

An object of the present invention is to solve the above-mentioned problems, and to provide virtually no or very short wait time, low power consumption, no offset phenomenon, and fixation of toner images on recording materials. The present invention provides a novel heat fixing method that is favorable.

Another object of the present invention is to provide a toner for heat fixing that is preferably used in the heat fixing method provided in the present invention.

Still another object of the present invention is to provide a heat fixing method that does not require a special heat-resistant bearing because it does not use a high-temperature rotating roller.

Still another object of the present invention is to provide a heat fixing method that has a fixing device configuration that does not require direct hand contact with a high-temperature body, and is highly safe or does not require a protective member.

[Means and effects for solving the problems] The present invention provides a method for heating and fixing a toner image on a recording material, in which the toner is produced by suspending a monomer composition to the toner particle size in an aqueous medium and polymerizing the monomer composition. It is a suspension polymerization toner, and the toner has a melt viscosity of 1 to 250c at 160°C.
ps range, and contains 0.1 to 20% by weight of polyolefin graft-modified with an aromatic vinyl monomer and an unsaturated fatty acid or an unsaturated fatty acid ester based on the total toner. The present invention relates to a heat fixing method characterized in that heat fixing is carried out using a heating body fixedly supported by a heating body and a pressure member that is in opposing pressure contact with the heating body and brings the recording material into close contact with the heating body through a film.

Furthermore, the present invention provides heating using a heating body that fixes and supports a toner image on a recording material, and a pressure member that is in pressure contact with the heating body and brings the recording material into close contact with the heating body through a film. In the toner used in the fixing method, the toner is a suspension polymerized toner produced by suspending a monomer composition to the toner particle size in an aqueous medium and polymerizing the toner, and the toner has a melt viscosity at 160°C. 1-250
cps range of polyolefin graft-modified with an aromatic vinyl monomer and an unsaturated fatty acid or an unsaturated fatty acid ester, to the total toner.
The present invention relates to a heat fixing toner characterized by containing % by weight.

One of the structural features of the heat fixing method of the present invention is that the toner used is graft-modified with an aromatic vinyl monomer and an unsaturated fatty acid or an unsaturated fatty acid ester as a releasing component. The viscosity is
The content of modified polyolefin of 1 to 250 cps is 0.1 to 20% by weight in the total toner.

The polyolefin is a homopolymer of α-olefin such as ethylene, propylene, 1-butene, 1-hexene, 1-decene, 4-methyl-neepentene, or a copolymer of two or more α-olefins. Furthermore, oxides of polyolefins are also included.

The unsaturated fatty acids or unsaturated fatty acid esters used to synthesize graft-modified polyolefins include:
Methacrylic acid and methyl methacrylate, ethyl methacrylate, propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, n-octyl methacrylate, 2-ethylhexyl methacrylate, lauryl methacrylate, stearyl methacrylate, dodecyl methacrylate, phenyl methacrylate, dimethylaminoethyl methacrylate, diethylamino Ethyl methacrylate, 2-hydroxyethyl methacrylate, 2,2.2-trifluoroethyl methacrylate,
Methacrylates such as glycidyl methacrylate, acrylic acid and methyl acrylate, ethyl acrylate, propyl acrylate, n-butyl acrylate, isobutyl acrylate, n-octyl acrylate, lauryl acrylate, stearyl acrylate, dodecyl acrylate, 2-ethylhexyl acrylate, phenyl Acrylates such as acrylate, 2-chloroethyl acrylate, 2-hydroxyethyl acrylate, cyclohexyl acrylate, dimethylaminoethyl acrylate, diethylaminoethyl acrylate, dibutylaminoethyl acrylate, 2-ethoxy acrylate, l,4-butanediol diacrylate maleic acid, fumaric acid, itaconic acid, citraconic acid and monoethyl maleate, diethyl maleate, monopropyl maleate, dipropyl maleate, monobutyl maleate, dibutyl maleate, di-2-ethylhexyl maleate, mono Unsaturated dibasic acid esters such as ethyl fumarate, diethyl fumarate, dibutyl fumarate, di-2-ethylhexyl fumarate, monoethyl itaconate, diethyl itaconate, monoethyl citraconate, diethyl citraconate, etc. can be used, and one or more of these can be used simultaneously.

Further, aromatic vinyl monomers include styrene, 0-methylstyrene, m-methylstyrene, p-methylstyrene,
α-methylstyrene, 2.4 dimethylstyrene, p-ethylstyrene, p-n-butylstyrene, p-jert
-Butylstyrene! '-n-dodecylstyrene, p-
Examples include phenylstyrene and p-chlorostyrene, and one of these or 2f! ! The above can be used simultaneously.

As a method for graft modification, conventionally known methods can be used. For example, grafting can be achieved by heating and reacting the polyolefin with an aromatic vinyl monomer and an unsaturated fatty acid or an unsaturated fatty acid ester in a solution or molten state in the atmosphere in the presence of a radical initiator under pressure if necessary. A modified polyolefin is obtained. Grafting with an aromatic vinyl monomer and an unsaturated fatty acid or an unsaturated fatty acid ester may be carried out simultaneously or individually.

Examples of initiators used in the grafting reaction include benzoyl peroxide, dichlorobenzoyl peroxide, di-tert-butyl peroxide, lauroyl peroxide, tert-butyl perphenylacetate, cumin perpivalate, azobis-isobutyronitrile. , dimethyl azoisobutyrate, dicumyl peroxide and the like.

The ratio of the grafting agent to the polyolefin is preferably 0.1 to 100 parts by weight, more preferably 1 to 50 parts by weight, based on 100 parts by weight of the polyolefin. If the amount is less than 1 part by weight, the grafting effect will hardly be exhibited, and if it is more than 100 parts by weight, the advantageous properties originally possessed by the polyolefin will be lost.

The weight ratio of aromatic vinyl monomer to unsaturated fatty acid or unsaturated fatty acid ester is preferably 95:5 to 5:95, more preferably 80:20 to 20:80. When there is a large amount of unsaturated fatty acids or unsaturated fatty acid esters, the mold release effect of the polyolefin tends to decrease, and when there is a large amount of aromatic vinyl monomers, the dispersibility of the polyolefin in the toner does not improve much.

The amount of the graft-modified polyolefin used in the present invention is 0.1 to 2 parts by weight per 100 parts by weight of the binder resin.
It is preferably 0 parts by weight, more preferably 0.5 to 10 parts by weight. When the amount is less than 0.1 parts by weight, a sufficient mold release effect may not be exhibited, and when it is more than 20 parts by weight, the blocking properties of the toner tend to deteriorate.

In addition, the graft-modified polyolefin used in the present invention is
It is preferable that the melt viscosity at 160°C is in the range of 1 to 250 cps. If it is less than 1 cps, toner blocking tends to occur, and if it is more than 250 cps, it becomes difficult for the modified polyolefin to ooze out from the toner, making it difficult to exhibit the mold release effect. In the fixing method of the present invention, it is generally preferable to use a release component having a lower melt viscosity as the fixing temperature is lower.

The melt viscosity referred to in the present invention is a value measured by a B-type rotational viscometer.

The toner particles used in the present invention can be obtained, for example, by the method shown below. That is, a monomer system in which a polymerizable colorant, a polymerization initiator, and, if necessary, a crosslinking agent, a charge control agent, a polar polymer, and other additives are uniformly dissolved or dispersed, is added to an aqueous phase containing a suspension stabilizer ( (that is, a continuous phase), and granulation polymerization is carried out under stirring. Thereafter, the suspension stabilizer is removed, and the product is separated from the oven and dried.

It is particularly preferable to obtain the toner by the suspension polymerization method described below because the particle size distribution is sharp.

Polymerizable monomers that can be applied to form the toner particles are heptamers having a CH2-C< group as a reactive group, such as styrene, 0-methylstyrene, m-methylstyrene, p-methylstyrene, p-methylstyrene, and p-methylstyrene. - Styrene and its derivatives such as methoxystyrene and p-ethylstyrene Niacrylic acid, methacrylic acid, maleic acid, maleic acid half esters: methyl methacrylate, ethyl methacrylate, propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, α-Methylene aliphatic monocarboxylic acid esters such as n-octyl methacrylate, dodecyl methacrylate, 2-ethylhexyl methacrylate, stearyl methacrylate, phenyl methacrylate, dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate; acrylic acid Methyl, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, propyl acrylate, n-octyl acrylate, dodecyl acrylate, 2-ethylhexyl acrylate, stearyl acrylate, 2-chloroethyl acrylate, phenyl acrylate, etc. Acrylic acid esters: There are monomers having a reactive double bond such as a vinyl group, such as acrylic acid or methacrylic acid conductors such as acrylonitrile, methacrylonitrile, and acrylamide.

These may be used alone or in combination. A crosslinking agent may be used if necessary. Examples of the crosslinking agent include divinylbenzene, divinylnaphthalene, diethylene glycol dimethacrylate, and ethylene glycol dimethacrylate. The amount of the crosslinking agent added is usually 0.1 to 5 parts by weight per 100 parts by weight of the polymerizable monomer. Further, a small amount of a polymer of these polymerizable monomers may be added to the monomer composition.

Among the above monomers, a mixture of a styrene monomer in which styrene and/or an alkyl group is substituted with a halogen group, and an acrylic monomer such as ethyl acrylate or butyl methacrylate is particularly preferred in the present invention. This is a structural feature of the present invention, which is an aromatic vinyl monomer, a polyolefin graft-modified with an unsaturated fatty acid or an unsaturated fatty acid ester, and raw material components of a suspension polymerized toner. styrenic monomer and
Due to the close approximation or identity with the acrylic monomer, the dispersibility and partial solubility of the graft-modified polyolefin during suspension polymerization increase, resulting in improved developability, offset resistance, and offset resistance as a developer toner. It is thought that durability is also improved.

Therefore, the monomer composition of the suspension polymerized toner in the present invention is such that 80% by weight or more of the styrene monomer and acrylic monomer based on Kaneko Tsuma, and further considering the development characteristics and blocking resistance, The weight ratio of styrene monomer and acrylic monomer is 95:5 to 6.
The ratio is preferably 0:40.

Further, a preferable polymerized toner can be obtained by adding a polar polymer, a polar copolymer, or a cyclized rubber having a polar group as an additive during polymerization of the monomer to polymerize the polymerizable monomer. The polar polymer, polar copolymer or cyclized rubber is preferably added in an amount of 0.5 to 501 parts by weight, preferably 1 to 40 parts by weight, per 100 parts by weight of the polymerizable monomer. If it is less than 0.5 parts by weight, it is difficult to obtain a sufficient pseudocapsule structure, and if it exceeds 50 parts by weight, the amount of polymerizable monomer becomes insufficient and the properties as a polymerized toner tend to deteriorate.

A polymerizable monomer composition containing a polar polymer, a polar copolymer, or a cyclized rubber is suspended in an aqueous phase of an aqueous medium in which a dispersant having an opposite charge to the polar polymer is dispersed, and polymerization is carried out. That is, the cationic or anionic polymer, cationic or anionic copolymer, or anionic cyclized rubber contained in the polymerizable monomer composition is preferably dispersed in an aqueous medium. The oppositely charged anionic or cationic dispersant is electrostatically attracted to the surface of the toner particles, and the dispersant covers the particle surface to prevent the particles from coalescing.
In addition to stabilizing the toner, the added polar polymer, polar copolymer, or cyclized rubber gathers on the surface layer of the toner particles, forming a kind of shell-like form, and the resulting particles become pseudo-capsules. . Since the relatively high molecular weight polar polymer, polar copolymer, or cyclized rubber gathered on the surface layer of the particles encapsulates a large amount of low softening point compounds inside the toner particles, the polymer particles of the present invention have blocking properties. Provides excellent developability and abrasion resistance. Examples of polar polymers (including polar copolymers and cyclized rubbers) and counterloadable dispersants that can be used in the present invention are shown below. In addition, the polar polymer is GPC
The weight average molecular weight measured at 5.00θ~50G, (1
00 is preferably used because it dissolves well in the polymerizable monomer and has durability.

(i) Examples of the cationic polymer include polymers of nitrogen-containing monomers such as dimethylaminoethyl methacrylate and diethylaminoethyl acrylate, copolymers of styrene and the nitrogen-containing monomers, styrene, unsaturated carboxylic acid esters, etc. There is also a copolymer of the nitrogen-containing monomer and the nitrogen-containing monomer.

(ii) Examples of anionic polymers include polymers of nitrile monomers such as acrylonitrile, polymers of halogen-containing monomers such as vinyl chloride, polymers of unsaturated carboxylic acids such as acrylic acid, and polymers of unsaturated carboxylic acids such as acrylic acid. There are polymers of basic acids, polymers of anhydrides of unsaturated dibasic acids, and copolymers of styrene and the monomer.

The dispersant is preferably an inorganic fine powder that has the ability to stabilize the dispersion of the monomer composition particles in an aqueous medium and is sparingly soluble in water. The amount of dispersant added to the aqueous medium is 0.1 to 50% based on water! II amount% (preferably 1 to 201i amount%)
) should be added.

(ii+) As the anionic dispersant, Aerosil #
There are colloidal silicas such as 200.1300 (manufactured by Nippon Aerosil Co., Ltd.).

(iν) As a cationic dispersant, aluminum oxide,
Examples include magnesium hydroxide and hydrophilic positively charged silica fine powder such as aminoalkyl-modified colloidal silica treated with a coupling agent.

An anionic cyclized rubber may be used instead of the above-mentioned polar polymer or copolymer.

To produce magnetic toner particles, magnetic particles are added to the monomer composition. In this case, the magnetic particles also serve as a coloring agent. The magnetic particles that can be used in the present invention include substances that are magnetized when placed in a magnetic field, such as iron,
Examples include powders of ferromagnetic metals such as cobalt and nickel, and powders of alloys and compounds such as magnetite and ferrite. Particle size is 0.05 to 5 μm, preferably 0.1
Magnetic fine particles having a diameter of ~1 μmμ are used. The content of the magnetic particles is preferably 10 to 60% by weight, preferably 20 to 50% by weight, based on the weight of the toner. In addition, these magnetic fine particles may be treated with a treatment agent such as a silane coupling agent, a titanium coupling agent, or an appropriate reactive resin. In this case, the surface area of the magnetic fine particles and the density of hydroxyl groups present on the surface Although it depends on the
A treatment amount of ~3% by weight) provides sufficient dispersibility in the polymerizable monomer and low softening point compound, and does not adversely affect the physical properties of the toner particles. Suspension-polymerized toner particles contain a colorant, and pigments such as conventionally known dyes, carbon black, and grafted carbon black, in which the surface of carbon black is coated with a resin, can be used. It is. The colorant is 0.5-3 based on the entire suspension polymerized toner containing the polymer and modified polyolefin.
Contains 0% by weight. A charge control agent and a fluidity modifier may be added to the toner as necessary.

In the suspension polymerization method, monomers and, as mentioned above, additives such as colorants, charge control agents, and polymers added as necessary, and the modified polyolefin according to the present invention are uniformly added. (i) As described in JP-A No. 62-295073, the monomer composition dissolved and dispersed is heated above the melting point of the modified polyolefin, and then cooled below the melting point to obtain the monomer composition. A method of precipitating modified polyolefin particles and performing a polymerization step described later to produce a suspension polymerized toner; and (ii) a method of suspension polymerizing a monomer composition without going through such a precipitation step. There is.

In the latter method (11), the melting point of the modified polyolefin is
It is mainly used when the temperature is lower than that during suspension polymerization, but
In the case of the present invention, the above (i)
, (ii) may be used.

In the polymerization method, the above monomer composition is added in an amount of 0.1 to 50% by weight.
A suspension stabilizer (e.g., a poorly soluble inorganic dispersant) is added to an aqueous medium (e.g., heated to a temperature of 5° C. or higher, preferably 10° C. to 30° C. or higher than the polymerization temperature). Disperse using a stirrer, homomixer, homogenizer, etc. Preferably, the agitation speed, time and setting are such that the particles of the molten or softened monomer composition have the desired toner particle size, generally less than 30 micrometers (e.g., a volume average particle size of 0.1 to 20 micrometers). Adjust the temperature of the aqueous medium. Thereafter, the temperature of the aqueous medium is lowered to the polymerization temperature while stirring to an extent that prevents sedimentation of the particles so that the state is almost maintained by the action of the dispersion stabilizer.The polymerization temperature is preferably 50°C or higher. is set at a temperature of 55 to 80°C, particularly preferably 60 to 75°C, and a substantially water-insoluble polymerization initiator is added while stirring to carry out polymerization. After the reaction is completed, the produced toner particles are collected by an appropriate method such as washing, removal of the dispersion stabilizer, filtration, decantation, centrifugation, etc., and dried to obtain toner particles that can be used in the present invention. In the suspension polymerization method, 200 to 3 parts of water is usually added to 100 parts by weight of the polymerizable monomer and low softening point compound.
,000 parts by weight are used as the aqueous dispersion medium.

Furthermore, in the present invention, the melt viscosity of the toner is 1
10' to 106 poise in any range of 20 to 150°C, and when the logarithm (innη') of melt viscosity η' in the range of 120°C to 150°C is plotted against temperature. , the absolute value of the slope of the graph is 0.
It is preferable that the toner has physical properties of 50 I2n (poise)/'e or less in terms of fixing properties and anti-offset properties.

Here, the melt viscosity was measured using an elevated flow tester (Shimadzu flow tester (FT-500 type)) shown in Figure 1. 10k by plunger 101 under temperature
A load of g-f was applied and the sample was extruded from a nozzle 104 having a diameter of 1 mm and a length of 1 mm, thereby measuring the plunger descent amount (outflow velocity) of the flow tester. This outflow rate was measured at each temperature (5°C in the temperature range of 120 to 150°C).
The apparent viscosity η' can be determined from this value using the following formula.

However, η′2 Apparent viscosity (poise) TW′: The apparent viscosity of the tube wall is shear reaction (dyne/cm2)D
W': Apparent shearing velocity of the tube wall (17 sec) Q: Outflow velocity (cm37 sec = mi)/5 ec) P: Extrusion pressure (dyne/cm2) [10 kg-f-980XlO
'dyne] R: Nozzle radius (cm) L: Nozzle length (cm) In the heat fixing method of the present invention, the "viscosity" and "inclination" of the toner are unique to each toner, and the toner's It shows sensitivity to temperature and is involved in binding properties and toner particle deformation during fixed image formation. Especially in a fixing method using a film, there is a strong correlation with the fixing process.

If the melt viscosity at 120°C to 150°C exceeds 1O'poise, particle deformation during heat fixing is difficult to occur and binding property does not increase, causing poor fixing, and a large amount of energy is required to compensate for this. becomes. On the other hand, 10'
If it is less than poise, bleeding on the transfer paper or seepage into the transfer paper is likely to occur, and the absolute value of the °° inclination is 0.50j! If it is larger than n (poise)/'C'', the particles will be sensitive to temperature and show a rapid change in viscosity, making it impossible to maintain sufficient latitude in the fixing temperature, resulting in poor fixing and seepage. has a large dependence on the fixing processing speed (mm/5ec).This "slope" is also related to the viscosity change during cooling after particle melting during fixing, and "the absolute value of the slope is 0". .50
When it becomes larger than 11n (poise) /'e'',
There are disadvantages such as an increase in the offset phenomenon to the film, a noticeable gloss on the fixed image, and a deterioration in image quality.

In the present invention, the "slope" of viscosity is the value obtained by connecting the measurement point at t1°C and the measurement point at tb°C in the graph with a straight line, and calculating the "slope 1" by the following, as shown in Figure 2. is approximated and used as the “inclination” of the slope.

(However, jnη1' represents the value obtained by taking the natural logarithm of the viscosity at t1°C, and jnηb' represents the value at tb°C.) In the heat fixing method of the present invention, the suspension polymerized toner used has a thermal differential From 10℃ to 200℃ using the analyzer DSC
As a result of measurement in the measurement range up to .degree. C., toners exhibiting a maximum value of the first endothermic peak of 40.degree. C. to 120.degree. C. are preferable, and toners exhibiting characteristics of 55.degree. C. to 100.degree. C. are particularly preferable.

Further, it is preferable that the temperature at which the film is peeled off from the surface to which the toner is fixed is higher than the endothermic temperature, more preferably 30°C or more (more preferably 40 to 150°C) higher than the endothermic temperature. In other words, it is preferable to peel off the toner in a molten state.

The method for measuring the maximum value of the endothermic peak in the present invention is calculated in accordance with ASTM D-3418-82.

Specifically, 10 to 15 mg of toner is collected, heated in a nitrogen atmosphere from room temperature to 200°C at a temperature increase rate of 10°C/min, held at 200°C for 10 minutes, and then rapidly cooled. After pre-treating the toner, repeat the 10
℃ for 10 minutes and a heating rate of 10t/min.
Heat to 00℃ and measure. Generally, the data shown in FIG. 3 is obtained, and the maximum value of the endothermic peak that appears first is defined as the endothermic temperature TD in the present invention.

In the present invention, the heating body has a smaller heat capacity than a conventional heating roll and has a linear heating section, and the maximum temperature of the heating section is preferably 100 to 300'C.

The film located between the heating body and the pressure member is preferably a heat-resistant sheet with a thickness of 1 to 100 μm, and these heat-resistant sheets include highly heat-resistant polyester, PET (polyethylene), etc. terephthalate)
, PFA (tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer), PTFE (polytetrafluoroethylene), polyimide, polyamide, and other polymer sheets, as well as metal sheets such as aluminum, and metal sheets and polymer sheets. A laminate sheet is used.

A more preferable film configuration is that these heat-resistant sheets have a release layer and/or a low resistance layer.

[Example] Hereinafter, preferred embodiments of the present invention will be described based on the accompanying drawings, but this is not intended to limit the present invention in any way.

FIG. 5a shows a structural diagram of the fixing device of the present invention.

Reference numeral 11 denotes a low heat capacity linear heating element that is fixedly supported on the device. For example, a resistance material 13 is coated on an alumina substrate 12 having a thickness of 1.0 mm, a width of 10 mm, and a longitudinal length of 240 mm.
It is coated to a thickness of 0 mm and is energized from both ends in the longitudinal direction.

The current is supplied with a DClooV pulse-like waveform with a period of 20 m5 ec to a desired temperature controlled by the thermometer 14.
A pulse is given by changing the pulse width depending on the amount of energy released. Approximate pulse width is 0.5m5ec~5m5
It becomes ec. The fixing film 15 moves in the direction of the arrow in the figure while coming into contact with the heating body 11 whose energy and temperature are controlled in this way. As an example of this fixing film, the thickness is 20 μm.
heat-resistant film, such as polyimide, polyetherimide, PES, PFA, with P at least on the image contact side.
It is an endless film coated with a release layer of 10 μm, which is made by adding a conductive material to a fluororesin such as TFE or PAF.

Generally the total thickness is less than 100μ, preferably less than 40μ. The film is driven eight times in the direction of the arrow without wrinkles by the driving and tension of the driving roller 16 and the driven roller 17.

Reference numeral 18 denotes a pressure roller having a rubber elastic layer with good mold releasability such as silicone rubber, which presses the heating body through the film with a total pressure of 4 to 20 kg and rotates in pressure contact with the film. The unfixed toner 20 on the transfer material 19 is guided to a fixing section by a population guide 21, and a fixed image is obtained by the above-mentioned heating.

The above was explained using an endless belt, but as shown in Figure 5b,
The sheet feeding shaft 24 and the winding shaft 27 may be used, and the fixing film may be a film with ends.

Further, as an image forming apparatus, the present invention is applicable to all the fixing devices of apparatuses that form images using toner, such as copying machines, printers, and fax machines.

When the temperature detected by the temperature measuring element 14 in the low heat capacity linear heating element 11 is T, the surface temperature T2 of the film 15 facing the resistance material 13 is approximately equal to T1. Further, the film surface temperature T at the portion where the film 15 is peeled off from the toner fixed surface is approximately equal to the temperatures TI and T2.

An example of manufacturing a suspension polymerized toner according to the heat fixing method of the present invention and an example of the heat fixing method are shown below.

After mixing the above components, 1 part by weight of di-tert-butyl peroxide was added to the mixture to prepare a monomer composition. The monomer composition was added to Aeroseal #20.
0 (manufactured by Nippon Aerosil Co., Ltd.) was added to an aqueous medium containing 2,000 parts by weight of heated ion-exchanged water with 10 parts by weight under stirring using a TK homo mixer, and heated at 10,00 O for 25 minutes after addition.
The mixture was dispersed and granulated by stirring with Or, p, and m.

Furthermore, the stirring was changed to paddle blade stirring, and the mixture was stirred for 20 hours under heating to complete the polymerization. After that, it is cooled, washed with sodium hydroxide solution to dissolve and remove the silica, washed with water,
It was dehydrated, dried, and classified to produce suspension polymerized toner particles having a volume average particle size of 12 μm.

FIG. 4 shows the relationship between the melt viscosity and temperature of the toner.

Further, To of this toner was 63°C.

After mixing the above components, 0.8 parts by weight of cumene hydroperoxide was added to the mixture to prepare a monomer composition.

A suspension polymerized toner was produced using the monomer composition in substantially the same manner as in Toner Production Example 1.

The relationship between the viscosity and temperature of the produced toner is shown in (b) in Figure 4.
).

Further, the TD of this toner was 66°C.

1j Item 1j Made by Niji Co., Ltd. After mixing the above components, the mixture was heated to 150° C. under closed conditions to dissolve the modified polyolefin. Next, this was cooled to 70° C. while stirring to precipitate modified polyolefin particles.

In the monomer composition thus obtained, as a polymerization initiator,
A suspension polymerized toner was produced in substantially the same manner as in Toner Production Example 1 by adding azobisisonitrile.

The relationship between the viscosity and temperature of the produced toner is shown in FIG.
Shown in c).

Further, To of this toner was 68°C.

Example 1 2 parts by weight of the suspension polymerized toner of Production Example 1 and 100 parts by weight of carrier
Parts by weight were mixed to obtain a developer.

This developer is used in a commercially available copier (Canon NP).
-1215 (manufactured by Canon), the recording material on which the toner unfixed image was formed was taken out, and this was applied to the fifth
This was applied to the fixing device shown in Figure a.

In this fixing device, the temperature measuring element surface temperature T of the heating body,
is 200℃, the power consumption of the resistance material of the heating part is 150W,
The total pressure of the pressure roller is 15 kg, the nip between the pressure roller and the film is 3 mm, and the fixing speed is 100 mm/s.
ec, and as the heat-resistant sheet, a 20 μm thick polyimide film having a low-resistance release layer made of PTFH with a conductive substance added thereto was used on the contact surface with the recording material. At this time, the time required for the surface temperature T of the temperature measuring element of the heating body to reach 180° C. was about 2 seconds. Furthermore, the temperature T2 at this time is 177°C.

The temperature was 176°C. As recording materials, commercially available copier paper, Canon New Dry Vapor (Canon Sales Co., Ltd. 54)
g/m2) was used.

The obtained image was free from toner penetration into the paper, which is a practical matter, had good fixing properties, and had no offset on the film after being used for 5,000 sheets.

Example 2 2 parts by weight of the toner of Production Example 2 and 100 parts by weight of carrier were mixed to obtain a developer.

When this developer was evaluated in the same manner as in Example 1, it was found that there was no offset phenomenon after 5,000 sheets, and it had excellent fixing properties. Good images with no bleeding were obtained.

Also, the time and temperature T2 until the surface temperature T1 of the temperature measuring element of the heating body reaches 180°C. T3 was almost equivalent to Example 1.

Example 3 2 parts by weight of the suspension polymerized toner of Production Example 3 and 100 parts by weight of carrier
The weights were mixed to obtain a developer.

This developer is used in a commercially available copier (Canon NP).
-3225 (manufactured by Canon) was applied to the modified machine, the unfixed image of the toner was taken out, and this was applied to the fifth
The image obtained by fixing was performed using the fixing device shown in Fig. a and was evaluated.

The images obtained are clear and the toner does not penetrate into the recording paper.
It was easy to apply and had good fixing properties. Furthermore, no toner offset phenomenon was observed in the film after 5,000 sheets of durability.

Also, the time and temperature T2 until the surface temperature T1 of the temperature measuring element of the heating body reaches 200°C. T3 was almost equivalent to Example 1.

Comparative Example 1 Toner E was produced in substantially the same manner as in Production Example 3, except that a commercially available unmodified polyethylene wax (melt viscosity η at 160° C. was 300 cps) was used instead of the graft-modified polyolefin. .

A fixing test was conducted in the same manner as in Example 3 using the fixing device shown in FIG. 5(a). The fixing property was usable for practical use, but compared to Example 3, it was slightly inferior.

Further, the offset resistance was inferior to that of Example 3, as some toner adhesion was observed when the fixing film 15 and pressure roller 18 were observed after 5,000 sheets had been passed.

[Effects of the Invention] As described above, according to the present invention, toner can be heat-fixed quickly and reliably, and high-quality images can be provided.

[Brief explanation of drawings]

In the accompanying drawings, FIG. 1 shows a schematic cross-sectional view of an elevated flow tester for measuring the melt viscosity of toner or binder resin. FIG. 2 is a graph showing the slope of the natural logarithm of the viscosity of toner or binder resin with respect to temperature. FIG. 3 is a graph showing the endothermic peak of toner. Figure 4 shows the suspension polymerization toner used in the present invention at 120°C.
It is an example of a graph showing melt viscosity characteristics at ~150°C. FIG. 5a shows a schematic cross-sectional view of a fixing device for implementing the fixing method of the present invention, and FIG. 5b shows a schematic cross-sectional view of the fixing device for implementing the fixing method of another aspect of the present invention. Show the diagram. 11... Heating body 12... Alumina substrate 13
... Resistance material 14 ... Temperature measuring element 15 ... Fixing film 16 ... Drive roller 17 ... Followed roller 18 ... Pressure roller 19 ... Recording material
20... Unfixed toner visible image 21... Entrance guide

Claims (2)

[Claims] (1) In a method of heating and fixing a toner image on a recording material, the toner is a suspension polymerized toner produced by suspending a monomer composition to a toner particle size in an aqueous medium and polymerizing it, and in the toner, Melt viscosity at 160°C is 1-250
cps range of polyolefin graft-modified with an aromatic vinyl monomer and an unsaturated fatty acid or an unsaturated fatty acid ester, to the total toner.
% by weight, and heats a visible image of the toner by a heating body fixedly supported on a recording material and a pressure member that is in opposing pressure contact with the heating body and brings the recording material into close contact with the heating body through a film. A heating fixing method characterized by fixing. (2) A toner image is heated and fixed on the recording material by a heating body that is fixedly supported and a pressure member that is in pressure contact with the heating body and brings the recording material into close contact with the heating body through a film. In the toner used in the fixing method, the toner is a suspension polymerized toner produced by suspending a monomer composition to a toner particle size in an aqueous medium and polymerizing it, and the toner has a melt viscosity of 1 to 250 cps at 160°C. A toner for heat fixing, characterized in that it contains 0.1 to 20% by weight of a polyolefin graft-modified with an aromatic vinyl monomer and an unsaturated fatty acid or an unsaturated fatty acid ester, based on the total toner.