JPH0456869A - Toner - Google Patents

Abstract

PURPOSE:To prevent a blocking phenomenon by using a binder showing the specified physical values. CONSTITUTION:The binder having the following physical values is used; <=30 dyne/cm of a surface tension at 200 deg.C, >=100 poise of a melt viscosity, >=100 dyne/cm<2> of a storage elasticity and <=5,000 poise of a melt viscosity at 125 deg.C, and <=40,000 dyne/cm<2> of a storage elasticity. In order that the temp. characteris tic of the binder, and the storage acid generating ratio are kept relatively higher at a high temp. and lower at a low temp., the binder showing a high melt viscosity and a high storage elasticity at a high temp. melting time and the binder resin showing a low melt viscosity and a low storage elasticity at a low temp. melting time are properly blended and used. Thus the void resistance characteristic and the fixing property are improved and the blocking phenome non is prevented.

Description

[Detailed Description of the Invention] [Summary] The purpose of the present invention is to provide a toner that is used for developing electrostatic latent images in electrophotography, etc., and has excellent void resistance and fixing properties, and is free from blocking phenomena. In the toner using a binder, the binder has a surface tension of 3Qd7ne/Cm or less at 200°C and a melt viscosity of 1
00 poise or more, storage modulus is 100 dyne/ci
f or more, the melt viscosity at 125° C. is 5000 poise or less, and the storage elastic modulus is 40000 d7ne/a (or less).

[Industrial Application Field] The present invention relates to a toner used for developing electrostatic latent images such as electrophotography.

As an electrophotographic method, the method described in US Pat. No. 2,297,691 and the like is well known. This generally uses a photoconductive insulator (such as a photocondrum) and applies a negative electrostatic charge on the photoconductive insulator by means of corona discharge, etc.
An electrostatic latent image is formed by irradiating a light image using various means, and this latent image is developed and visualized by electrostatically attracting a fine powder called toner, and if necessary, the toner is transferred to a recording medium such as paper. After the image is transferred, the toner image is fixed on the recording medium by means such as pressure, heating, blowing of solvent vapor, irradiation with light, etc. to obtain a printed photograph.

[Prior Art] In electrophotography, the toner for developing electrostatic latent images is a toner in which a coloring agent such as carbon black is dispersed in a binder resin made of natural or synthetic polymer material, and is used to develop an electrostatic latent image. Finely ground particles are used.

The toner is used alone or mixed with a carrier material such as iron powder or glass beads to develop an electrostatic latent image.

There are two types of developing methods: -component developing method and two-component developing method. The toner used in the former usually contains magnetic powder, and this toner is rubbed against the wall surface of the developing device and the members of the developing roll. The toner is triboelectrically charged by this, and is held on the developing roll by the magnetic force of the magnet contained in the developing roll, and as the developing roll rotates, the toner is carried to the latent image area of the photoconductive insulator, and only the charged toner is Development is performed by adhering to the latent image by electrical attraction.

In the latter two-component development method, the developer consisting of toner and carrier is mixed and stirred in the developing device and is triboelectrically charged, and the toner is supported on the carrier while the photoconductive insulator is hidden. Development is performed by carrying only the charged toner to the image area and selectively adhering it to the latent image by electrical attraction.

Heat roll fixing has traditionally been used to fix toner that has been visualized by developing an electrostatic latent image, but flash fixing, which uses the energy emitted from a xenon lamp, has attracted attention because of the following characteristics. ing.

■Since it is non-contact fixing, the resolution of the image during development does not deteriorate.

■No waiting time is required after the power is turned on, and immediate start is possible.

■Even if recording paper or other recording media gets stuck in the fuser due to system failure, it will not catch fire.

■Fixing is possible regardless of the material or thickness of the recording paper, such as adhesive paper, preprinted paper, or paper of different thickness.

Here, to explain the process in which toner adheres to a recording medium by flash fixing, the toner transferred to the recording medium adheres as a powder to form an image, and it crumbles when rubbed with a finger.

Next, when a flash of light is irradiated using a xenon flash lamp, the toner absorbs the energy of the flash, and as a result its temperature rises, softens and melts, and adheres closely to the record.

After the flash ends, the temperature drops and solidifies to produce a fixed image.

The toner requirements here are that it softens at a relatively low temperature and that the image does not deform even in the molten state.

However, when a solid, not just toner, melts, its viscosity decreases, and the melt aggregates and deforms due to surface tension, and in this case, the toner image is deformed.

Conventionally, low polymer polymers called oligomers have been used as binders for toners because of their low melting temperature and good thermal stability.

However, since these oligomers have low melt viscosity and storage modulus, the fixed image is easily deformed, which poses a problem as to whether the image quality will deteriorate.Furthermore, if the applied light energy is too strong, explosive fixing is likely to occur, which may cause the image to deteriorate. There is a problem in that white areas called voids occur, resulting in a decrease in image density.

FIG. 1 shows how voids occur in toner 1 arranged in multiple rows on recording paper 2 (a in the same figure).
When the toner 1 is irradiated with a strong flash 3 (b), the toner 1 easily melts due to its low softening temperature, but voids 5 are generated inside the toner 1 for the following reason (c). Note that 4 in FIG. 1 is a fixed image.

- When a portion of the toner 1 reaches a decomposition temperature and a decomposed gas is generated, the void 5 is formed by protruding.

- The air in the gaps between toner particles protrudes due to thermal expansion, and voids 5 are formed.

The void 5 is formed by this mechanism or the void 5 is caused by explosive settlement.

Furthermore, even if the toner 1 absorbs an appropriate amount of energy for melting from the flash 3, if the melt viscosity and storage modulus are too low relative to the surface tension of the toner 1, the toner 1 Void 5 may occur because the particles aggregate due to surface tension before solidifying each other. Note that this void phenomenon is more likely to occur in printers and copiers with short fixing times, that is, with high printing speeds, because it is necessary to irradiate a large amount of energy in a short period of time to perform fixing. This is particularly noticeable on high-speed aircraft.

As a means to solve these problems, if the molecular weight of the binder resin is simply increased, the melt viscosity and storage modulus of the toner 1 will increase, but the melting point of the toner 1 will also increase, and therefore the fixing properties of the toner 1 will generally deteriorate.

That is, in flash fixing, instantaneous light energy is applied from the upper part of the accumulated toner 1, and the heat generated by the energy is transmitted to the lower toner 1, melting the lower toner 1 and thereby fixing is performed ( Special Public Service 1977-14
0860), there is a temperature difference between the upper part of the toner and the lower part of the toner, and the lower part of the toner is relatively low temperature. For this reason,
When the melting point of the toner 1 is increased, the lower toner 1 hardly melts, resulting in extremely low fixability. This phenomenon becomes more pronounced as the thickness of the toner 1 deposited by development increases, and normally, if the thickness of the toner 1 after fixing exceeds 20 μm, good fixing performance cannot be maintained. However, it is difficult to always control the thickness of the developed toner 1 to be constant.

Further, the flash fixing toner 1 often uses a low polymer polymer with a lower softening temperature than the binder resin used in the hot roll fixing toner 1, and therefore, when exposed to a high temperature environment, the toner surface deteriorates. A blocking phenomenon may occur in which toner particles become soft and come together.

When the blocking phenomenon occurs, the fluidity of toner 1 is extremely reduced, which not only prevents toner from being smoothly supplied into the developing device, but also changes the charging characteristics due to changes in particle size, resulting in poor development. or become unable to do so.

Therefore, it was also necessary to develop a toner 1 that exhibits good fixing properties even if the amount of toner 1 to be developed varies to some extent, and that does not cause voids 5 or blocking phenomena.

[Problem to be solved by the invention] As described above, in the case of electrophotographic toners using a flash fixing method, conventionally used binders include epoxy resins such as bisphenol A diglycidyl ether polymer. However, when such a resin is used as a binder resin, it is necessary to use an oligomer having a low softening temperature, that is, a relatively low molecular weight, in order to obtain good fixing properties. Such oligomers are prone to explosive fixation due to thermal decomposition, and their high surface tension and low melt viscosity create voids due to aggregation, leading to a decline in image quality. There is also the problem that a blocking phenomenon is likely to occur when exposed to the air.

The present invention has been made in view of such conventional problems, and has excellent void resistance and fixing properties, and
The purpose is to provide a toner that does not cause blocking phenomenon.

[Means for Solving the Problems] In order to achieve the above object, the present invention provides a toner using a binder, wherein the binder has a surface tension of 30 + Iyne/am or less at 200°C, a melt viscosity of 100 poise or more, and The elastic modulus is 10Qdyne/a (
A binder is used which exhibits the above physical property values, and has a melt viscosity at 125° C. of 5000 poise or less and a storage modulus of 4 GOOOdyne/cnf or less.

Further, the present invention provides that the binder has a melt viscosity of 30 poise or more at 200°C and a storage modulus of 50 dy.
ne/'c! lf or more, and melt viscosity at 125°C is 3000 poise or less, storage modulus is 35000 d
A binder that is less than or equal to yne/car and 20
A binder having a melt viscosity at 0°C of 120 poise or more, a storage modulus of 120 d7ne/'cur or more, a melt viscosity at 125°C of 10,000 poise or less, and a storage modulus of +00,000 dYne/'ad or less is used as an essential component. It is something.

Further, the present invention provides a functional group as the binder that exhibits rubber-like elasticity at room temperature with respect to the first prepolymer or monomer that forms the main chain structure of the binder by polymerization, and that is capable of reacting with the first prepolymer or monomer. A second prepolymer having 1.5 equivalents or more of , or a main chain modified copolymer into which a monomer that becomes the same as the second prepolymer upon polymerization is used.

The present invention will be explained in more detail below.

Here, the measurement temperatures for physical property values such as surface tension and melt viscosity in the present invention are determined as described above based on the following reasons.

First, if we consider the flash fixing process of toner in chronological order, we will see: ■Flash light irradiation process (When toner is irradiated with flash light, the toner absorbs the energy of the flash light and generates heat, and its surface instantly becomes extremely ) ■Heat conduction/penetration process: (The heat on the surface is conducted to the underlying toner, and the entire toner softens and melts, penetrating into the recording medium.) ■Cooling/fixation process; (The toner temperature decreases. and hardens to produce a fixed image.

) The physical behavior such as surface tension involved in void generation is based on the physical properties of the toner surface where the toner is melted at a high temperature and the middle to upper layer of the toner. On the other hand, the fixing property is based on the behavior of the toner in the lower toner layer where the toner is relatively low temperature, such as the melt viscosity of the toner until it cools and solidifies, and the permeability of the toner into the recording medium. It is obvious that the thermal, mechanical, and chemical behavior of toner, which is deeply involved in void generation, cannot be discussed based on a single temperature such as the binder softening point. etc. are physical quantities that are temperature-dependent, and their values vary greatly depending on the measurement temperature.At the same time, their temperature-dependent characteristics also vary greatly depending on the toner constituent materials, such as the material of the binder resin. be.

Conventionally, binder resins for flash fixing toners have been disclosed in Japanese Patent Application Laid-open Nos. 57-79957 and 63-66563.
In addition, the melting point of the binder is
60 specifies the melt viscosity at the softening point, but as mentioned above, the melt viscoelasticity of the toner on the surface in contact with the recording medium is important for fixing properties, while the voids are determined by the surface tension of the upper layer of the toner. Melt viscoelasticity is important, and based on the experience of the present inventors, even if a toner that satisfies the physical property values described in the above patent is used, it does not necessarily mean that an excellent flash-fixed image will be obtained. is not limited.

Therefore, in developing the present invention, the temperatures of the upper toner layer and the lower toner layer in each process of the above-mentioned flash fixing were estimated based on the following experiment.

(1) Estimating the melting temperature of the upper part of the toner The aggregation of the toner due to surface tension, which is the cause of void formation, occurs immediately after irradiation with flash light, or when the toner is at a relatively high temperature and has a low melt viscosity and storage modulus. Therefore, first, the temperature of the upper part of the toner immediately after irradiation with flash light was estimated based on the temperature at which the binder resin is exposed and the components of the thermally decomposed fragments generated at that time.

First, the toner decomposition gas generated when the toner was irradiated with flash light and melted was collected, and its components were identified by gas chromatography-mass spectrometry (GC-MS method). Next, toners of the same composition were melted at a constant temperature using a heating furnace, the toner decomposition gas generated at that time was collected, and the components were identified in the same manner. The results shown in Table 1 were obtained by comparing the decomposed gases of the two and determining the temperature at which a decomposed gas of the same composition as in flash light melting is generated in heating furnace melting. Based on this result, it was estimated that the temperature reached by the upper part of the toner during flash fixing was 200° C. or higher.

(2) Estimating the temperature of the lower part of the toner On the other hand, the melt viscosity and storage elastic modulus of the lower part of the toner that is in contact with the recording medium are important factors for fixing performance.

Therefore, for five types of flash fixing toners having different melting characteristics, the temperature reached at the bottom of the toner when the optimum fixing energy is given to each toner was estimated using the following method. Note that the optimum fixing energy here refers to the energy at which the toner exhibits sufficient fixing strength and does not cause explosive fixing or the like due to excessive energy.

Specifically, the toner has a melting point (flow tester method) of 105
First, a fixing test was conducted using five types of polyester toners at temperatures of The optimum fixing energy was determined. Next, a thin layer (1 to 3 μm) of a heavy substance with a known melting point is formed on the recording medium, and a toner layer (about 10 μm) is formed on top of the thin layer, and a flash light is irradiated to melt the toner. Toner layer~
The temperature of the lower toner layer of each toner when the optimum fixing energy was applied was estimated based on whether the pure substance sandwiched between the recording media melted or not. The pure substances used were phenylacetic acid (melting point 76°C), benzyl (melting point 95°C), and acetanilide (melting point 95°C).
phenidone (melting point 121°C), zenacetin (melting point 135°C), phenanthrol (melting point 156°C), and benzanilide (melting point 163°C).

be.

The results are shown in Table 2.

From this, the temperature of the toner lower layer when the optimum fixing energy was applied was estimated to be 120 to 135°C.

Based on the above results, surface tension, melt viscoelasticity at high temperatures, etc., which are factors that cause void generation, should be discussed using physical property values in the temperature range of 200°C or higher, and melt viscosity, etc., which are involved in fixing properties, should be discussed. It was confirmed that the physical behavior should be discussed in the temperature range of about 125°C. In addition, regarding the present invention, the temperature at which the physical properties at high temperature melting are discussed is 200°C.
It was set as ℃. Based on the experience of the present inventors, this is 20
This is because it is possible to estimate the quality of toner fixing behavior using physical property values at 0°C as an indicator, and at higher temperatures thermal decomposition and thermal polymerization of the resin become more intense, making it difficult to discuss clear physical property values. It is something.

The above experiment was conducted using a printer (F-6700D; manufactured by Fujitsu) that employs a flash fixing method, and at a charging voltage of the light emitting capacitor in the range of +450V to 2550V.

As a result of the inventors' studies, the physical properties of the binder used in the toner were found to be 30d7ne/a at 200°C.
n (Wilhelmy method) or less, the melt viscosity is 100 poise or more, the storage modulus is 100 d7nt/aIr or more, the melt viscosity at 125°C is 5000 poise or less, and the storage modulus is 40000 dyne/a# or less. By doing so, it is possible to achieve both excellent flash fixing properties and void resistance. However, methods commonly used to increase melt viscoelasticity during high temperature melting, such as: Enlarge.

■Introducing a crosslinked structure between binder molecules.

If such a method is used, the toner's melting point and melt viscoelasticity at low temperature melting will also increase, resulting in poor toner fixing properties, and it has heretofore been difficult to fully satisfy both characteristics.

As a result of studies conducted by the present inventors, the temperature characteristics of the binder's melt viscosity and storage modulus are relatively high at high temperatures (specifically 10
0 poise or more / 100 dyne/a/ or more) and low at low temperatures (specifically 5000 poise or less / 400
00dyne/Ci or less), it is relatively easy to use by appropriately blending a binder that exhibits high melt viscosity and high storage modulus when melted at high temperature and a binder that exhibits low melt viscosity and low storage modulus when melted at low temperature. We have found that the above conditions can be achieved.

Specifically, as a binder with low melt viscosity and storage modulus when melted at low temperature, the melt viscosity at 200°C is 30 poise or more, the storage modulus is 50 dyne/cnf or more, and 1
A binder with a melt viscosity of 3000 poise or less at 25°C and a storage modulus of 35000 dyne/cnf or less and a binder with a high melt viscosity when melted at a high temperature of 200°C.
Melt viscosity at 120 poise or more, storage modulus 1
20 dyne/'ad or more, melt viscosity at 125°C is +0000 poise or less, storage modulus is 1OHO
By blending and using a binder with Qdyne/cm2 or less, the melt viscosity and storage modulus of the entire binder at 125°C is 5000 poise or less/400
0 G d y n e / at or less, and 2006
In C, 100 poise or more / 100 dyne /
cnf or higher.

Note that the lower limits of the melt viscosity and storage modulus at 200°C of Vanida, which exhibit low melt viscosity and low storage modulus when melted at low temperatures, are defined as 30 poise and 50 dyne/a, respectively, based on the experience of the present inventors. According to this, if a binder with a lower melt viscosity and storage modulus is blended at this temperature, the melt viscosity and storage modulus of the binder as a whole will decrease, even if a binder that exhibits a high melt viscosity and storage modulus at high temperature is blended. The rate is often below the desired value;
This is because, in extreme cases, the difference in melt viscosity between the two binders is large, causing problems such as layer separation between the two binders during melting.

On the other hand, the reason why the melt viscosity and storage modulus at 125° C. of a binder that exhibits high melt viscosity and high melt modulus when melted at high temperature are specified to be 10,000 poise and 100 HOdyne/d or less, respectively, is that the melt viscosity of this binder,
This is because if the storage modulus is high, even if it is blended with a binder having a low melt viscosity and a low storage modulus, the permeability to the recording medium will be poor, resulting in poor fixing.

It should be noted that the binder used in the above blend is also required to have a low melt viscosity and a low storage modulus when melting at a low temperature, and a high melt viscosity and a high storage modulus when melting at a high temperature, although the degree varies. According to the experience of the present inventors, it is difficult to obtain a binder that exhibits low melt viscosity and low storage modulus when melted at low temperature, and also exhibits high melt viscosity and high storage modulus. It is difficult to obtain a blending binder that satisfies the temperature-melt viscosity and storage modulus characteristics of the present invention by only partially changing the molecular structure, such as by controlling the molecular structure or introducing a crosslinked structure.

Therefore, as a result of our studies, the present inventors have found that as a method to obtain a binder that exhibits high melt viscosity and high melt elastic modulus when melted at high temperature while preventing an increase in melt viscoelasticity during low temperature melting that would cause an extreme rise in the softening point, It has been found that it is appropriate to use as a binder a main chain-modified copolymer whose main chain has been modified by introducing a component exhibiting rubber-like elasticity into the main chain.

In addition to the method of the present invention, methods for increasing the melt viscoelasticity of the binder resin when it is melted include: 1) increasing the degree of polymerization of the binder resin, 2) adding C4 or more to the main chain structure of the binder resin. Methods such as introducing a large number of long side chains, ■ introducing crosslinks between the main chain structures of the binder resin, etc. are possible, but in methods Since the softening point, melt viscosity at low temperature melting, and storage modulus also increase, although void generation can be prevented, fixing properties are often impaired. In addition, with method (2), it is possible to increase the melt viscosity during high temperature melting without increasing the softening point, the melt viscosity during low temperature melting, or the storage modulus, but the degree of this is still unclear. Furthermore, in this case, the glass transition point of the binder is lowered, and blocking resistance in a high-temperature environment is often extremely impaired.

In the method of the present invention using a main chain-modified copolymer which has been modified by introducing a component exhibiting rubber-like elasticity into the main chain, relatively crystalline copolymers such as epoxy and polyester can be used. By introducing a rubber elastic component with extremely low crystallinity into the main chain structure of a good polymer, the crystallinity of the main chain structure is reduced. This is a method of obtaining a binder that has a main chain structure but maintains softening point, melt viscosity at low temperature melting, and storage modulus almost the same as epoxy binders commonly used for flash fixing binders.

In addition, such binders have a longer main chain structure than epoxy binders commonly used in flash fixing binders, and furthermore, they have a region in the main chain structure that exhibits high flexibility and rubber elasticity. Because the chain structures are strongly intertwined, high melt viscosity can be maintained even at relatively high melting temperatures.

Prepolymers forming the main chain structure used in the present invention include epoxy resins, styrene-acrylic resins, polyester resins, vinyl resins, etc., as long as they have reactivity with rubber elastic components, and can be used as binder resins for toner. Can any commonly used resin be used?Introducing a rubber elastic component tends to lower the hardness of the binder resin, making it difficult to pulverize the toner after kneading, so the main chain As the prepolymer forming the structure, it is preferable to use a resin with relatively good crystallinity and high hardness.

Based on the experience of the present inventors, when the main chain is composed of bisphenol-type epoxy, it is desirable that the epoxy equivalent of the copolymer after modification of the main chain is 750 to 1000. When composed of
It is desirable that it be within the range of .

The reason for this is that if a main chain modified copolymer with a molecular weight smaller than the above range is used, it is difficult to obtain the desired temperature-melt viscosity and melt elastic modulus relationships, and if a main chain modified copolymer with a molecular weight larger than the above range is used. Because the binder becomes difficult to soften when used,
This is because fixing properties are often impaired.

In addition, the components exhibiting rubber-like elasticity used in the present invention include:
Polybutadiene or a copolymer containing butadiene as a constituent unit, such as 1.4 trans-polybutadiene, 1,4 cis-butadiene, 1.2-polybutadiene, butadiene-acrylonitrile copolymer, butadiene-styrene copolymer , butadiene-methyl methacrylate copolymer, butadiene-methyl vinyl ketone copolymer, etc. can be used.

In addition, these components exhibiting rubber-like elasticity may have functional groups such as epoxy groups, amino groups, carboxyl groups, and hydroxyl groups at their ends to impart reactivity with molecules forming the main chain structure. desirable.

The molecular weight of the component exhibiting rubber-like elasticity used in the present invention and the amount of modification to the main chain are arbitrary, or the molecular weight is 1000 to 1000.
5000, the amount of modification is 5 to 3 based on the weight of the main chain components
It is more desirable that it is 0W (%).

The molecular weight of the rubbery component used for modification is 1000 to 5000.
The reasons why it is more desirable to have a moderate amount of This is because when an oligomer having a molecular weight of about 1,000 to 5,000 in which several molecules of a rubbery component are polymerized is used, a main chain modified copolymer obtained by such block copolymerization can be obtained relatively easily.

In addition, the amount of modification is 5 to 30 w relative to the weight of the main chain constituent components.
The reason why it is more desirable that the amount of modification is 5w1% or less is that the effect of increasing melt viscosity during melting, which is described in the present invention when the amount of modification is 5w1% or less, is often difficult to appear, and 30vt96
If this is the case, the introduction of a rubbery component may cause problems, such as a decrease in the hardness of the modified copolymer and, when used as a toner binder, difficulty in pulverizing the toner after kneading. To become.

Note that the method for producing the main chain modified copolymer is arbitrary, but for example, when the prepolymer forming the main chain structure is a bisphenol-based epoxy resin, a bisphenol-type epoxy resin oligomer, a bisphenol compound, butadiene and/or isoprene may be used. as a raw monomer and an active hydrogen group capable of reacting with an epoxy group as 1. By reacting an oligomer containing 5 equivalents or more as an essential component,
A main chain modified copolymer can be obtained.

Similarly, when the prepolymer forming the main chain structure is a polyester, the polyester oligomer and butadiene and/or isoprene are used as raw monomers, and 1.5 equivalents of active hydrogen groups capable of reacting with carboxyl groups and/or hydroxyl groups are used. A main chain-modified copolymer can be obtained by reacting the oligomer containing the above as an essential component.

Furthermore, if the prepolymer forming the main chain structure is hydroxylated styrene-acrylic or carboxylated styrene-acrylic, the main monomers are styrene-acrylic oligomer and butadiene and/or isoprene, and
A main chain modified copolymer can be obtained by carrying out an esterification reaction using an oligomer containing 1.5 equivalents or more of active hydrogen groups capable of reacting with a hydroxy group or a carboxy group as an essential component.

In addition, as a method to reduce the adverse effects caused by the introduction of rubbery components, it is possible to supplementally use a method of introducing a partially crosslinked structure between the main chain skeletons and thereby increasing the melt viscosity and melt elastic modulus at high temperature melting. is also valid.

As a specific method, when the main chain skeleton is epoxy, a compound having active hydrogen in one molecule that can react with 3 or more equivalents of epoxy groups, such as N-aminoethylpiperazine, diethylenetriamine, triethylenetetramine, etc. , a method of crosslinking the epoxy rings of the main chain skeleton with metaxylene diamine, diaminodiphenylmethane, etc.
When the main chain skeleton is a polyester chain, the constituent monomer thereof is a compound having 3 or more equivalents of carboxyl group or hydroxyl group in one molecule, such as trimeri.

A method of containing appropriate amounts of toric acid, glycerin, pentaglycerol, pentaerythritol, 4,6-dioxy-2methylbenzophenone, etc. If the main chain skeleton is styrene-acrylic, as its constituent monomer, There is a method of containing an appropriate amount of a monomer containing two or more equivalents of unsaturated bonds, such as divinylbenzene.

In addition, when nitrogen-containing compounds are used as these crosslinking agents,
By selecting the structure of the nitrogen-containing compound and the number of nitrogen atoms in the compound, it is possible to obtain the secondary advantage that the charge imparting ability of the binder can be precisely controlled.

Furthermore, the main chain-modified copolymer of the present invention, which has undergone main chain modification by introducing a component exhibiting rubber-like elasticity into the main polymer, can be used alone as a binder, but other binder resins, That is, it is more desirable to use it by blending it with an epoxy resin, styrene-acrylic resin, polyester resin, vinyl resin, or the like.

The first reason why a binder blend is desirable is that by blending the binders as described above, the relationship between temperature, melt viscosity, and storage modulus of the binder can be controlled relatively easily.

The second reason is that as mentioned above, when the main chain is modified with a rubber-like elastic material, a certain degree of decrease in the strength of the copolymer is unavoidable, and when this main chain modified copolymer is used alone, This is because a decrease in toner pulverization efficiency is unavoidable.

From this point of view, the binder to be blended with this main chain modified copolymer should be a resin that has certain hard and brittle properties, such as an epoxy resin or a condensation of a short-chain linear diol and an aromatic dicarboxylic acid. More desirable are non-crosslinked polyesters formed by polymerization.

The third reason is that the main chain modified copolymer, which has been modified by introducing a component exhibiting rubber-like elasticity,
Although the degree of decrease in the glass transition temperature is smaller than when the side chain has a component exhibiting rubber-like elasticity, the glass transition temperature is still slightly lower due to the influence of having a component exhibiting rubber-like elasticity. This is because if this main chain modified copolymer is used alone as a binder, the toner may be blocked in a high temperature environment. From this point of view, it is desirable that the binder to be blended satisfies the above-mentioned temperature-melt viscosity and storage modulus relationships and has a high glass transition temperature. As a result of studies by the present inventors, the glass transition temperature of the binder blended into this main chain modified copolymer is preferably 70°C or higher, and the amount thereof is 5Qwt of the entire binder.
% or more is desirable.

The fourth reason is that by blending binders with different skeletal structures, the surface tension may be lower than when each binder is used alone. This is because toner binders are often made of oligomers or polymers that have a certain degree of polar groups, and the polar groups are oriented through hydrogen bonds, etc., which creates intermolecular attraction and increases surface tension. However, even in this case, by blending binders with different skeletal structures, the orientation of the polar groups is disturbed and the intermolecular force is reduced, resulting in a decrease in surface tension.

According to the experience of the present inventors, the binder used for blending has a melting temperature of 125°C or less, a weight average molecular weight of 20,000 or less, and a width of molecular weight distribution in which the value of weight average molecular weight/number average molecular weight is 4.0 or less. A narrow binder is more suitable for devices that perform high-speed flash fixing because the toner melts quickly when exposed to flash light.

Binders exhibiting such physical properties can be found in non-crosslinked bisphenol epoxy resins and non-crosslinked amorphous polyester resins.

In addition, for reasons such as preventing layer separation between binders during melting in the fixing process, when blending binders, it is preferable to partially react with each other during the kneading process during toner production to create a partially crosslinked product. is desirable.

Note that the toner used in the present invention can be manufactured by a conventionally known method. That is, the binder resin, colorant, inorganic filler, and charge control agent if necessary are cross-melted and uniformly dispersed using a pressure kneader, roll mill, extruder, etc., pulverized using a pulverizer such as a jet mill, and then classified. The desired toner can be obtained by classification using a machine, for example, a wind classifier.

Note that the various physical properties in the present invention were measured using the following measuring method.

(1) Surface tension The surface tension was measured at a measurement temperature of 200°C using the Welhelmi method surface tension measuring device “Digiomatic ESB-VJ (Kyowa Kagaku@)” equipped with a constant temperature sample holder with a temperature control range of ±0.5°C. This is the measured value.

(2) Melt viscosity/storage modulus Melt viscosity and melt modulus were measured using a cone-plate dynamic viscoelasticity measurement device MR-3 Soliquidometer (Kikushiology Co., Ltd.) at a heating rate of 10°C in a nitrogen atmosphere. / m i
This is a value obtained by measuring the temperature raised from 50°C to 250°C at n. Note that the frequency at this time was 0°5 Hz.

(3) Melting point The melting point can be measured using a flow tester [Shimabara Flow Tester CFT-500]
A heating flow test was conducted using J (Shimabara Seisakusho), and the value was obtained when the plunger was lowered by 4 mm. Note that the conditions for the temperature increase flow test are as follows.

・Die 1mmX1mmφ ・Sample 1.5g Pellet ・Preheating temperature 60℃ ・Preheating time 300 sec ・Heating rate 6℃ 7min ・Load 20kg+ (4) Glass transition temperature The glass transition temperature was measured using a differential scanning calorimeter rDSC-2OJ ((
It was determined from a temperature increase endothermic curve at a temperature increase rate of 5'C/min using a Seiko Electronics (Seiko Electronics).

[Examples] Hereinafter, the present invention will be explained in more detail based on Examples, but the present invention is not limited thereto.

First, the following 22 types of binders were prototyped as toner binders.

[Binder 1] Bisphenol A type epoxy oligomer, bisphenol A, and terminal carboxy-modified butadiene are essential components, and polybutadiene is contained in the main chain structure of the epoxy resin.
Butadiene-modified epoxy resin with w+% introduced [binder 2 cobisphenol A type epoxy oligomer, bisphenol A1 terminal carboxy-modified butadiene acrylonitrile as essential components, butadiene acrylonitrile copolymer introduced 17W1% into the main chain structure of the epoxy resin butadiene-acrylonitrile modified epoxy resin [Binder 3] Bisphenol A type epoxy oligomer, bisphenol A1-terminated sulfoxy-modified isoprene is an essential component, and 22wt of isoprene is contained in the main chain structure of the epoxy resin.
% introduced isoprene-modified epoxy [binder 4 cobisphenol A type epoxy oligomer, bisphenol A 1 terminal carboxy-modified butadiene-acrylonitrile, novolac as essential components, butadiene-acrylonitrile copolymer in the main chain structure of the epoxy resin 13
Partially cross-linked butadiene-acrylonitrile modified epoxy with vt% introduced [Binder 5] Bisphenol A type epoxy oligomer, bisphenol A 1-terminal amino-modified butadiene-acrylonitrile is an essential component, and butadiene-acrylonitrile copolymer is incorporated in the main chain structure of the epoxy resin. Partially cross-linked butane-acrylonitrile-modified epoxy with 10 wt% of introduced [Binder 6] Bisphenol A-type epoxy oligomer, bisphenol A-terminated sulfoxy-modified butadiene ~ acrylonitrile, metaxylene diamine as essential constituents, in the main chain structure of the epoxy resin Partially crosslinked butadiene-acrylonitrile modified epoxy with 13W1% of butadiene acrylonitrile copolymer introduced [Binder 7] Polyethylene terephthalate oligomer and terminal carboxy-modified isoprene are essential components, and 10W1% of isoprene is introduced into the main chain structure of polyethylene terephthalate. isoprene-modified epoxy [binder 8-coethylene glycol, 1,2-butylene glycol, polyoxyethylated bisphenol A1 terephthalic acid,
A polyester oligomer containing isophthalic acid and 2-methylterephthalic acid as essential constituents, and a terminal sulfoxy-modified butadiene-acrylnidonol as essential constituents,
Partially crosslinked butadiene-acrylonitrile modified polyester U binder 9j with 10w1% butadiene-acrylonitrile copolymer introduced into the main chain structure of the above polyester styrene, divinylbenzene, n-butyl acrylate,
Terminal hydroxylated crosslinked styrene acrylic oligomer containing hydroxymethyl acrylate as an essential component and partially crosslinked butadiene-acrylonitrile modified styrene-acrylic U binder containing terminal carboxy-modified isoprene as an essential component 10] Styrene, divinylbenzene, n-butyl acrylate Cross-linked styrene-acrylic as an essential constituent [Binder 11] Bisphenol A type epoxy oligomer, long-chain aliphatic carboxylic acid as an essential constituent, aliphatic carboxylic acid modified with long-chain aliphatic carboxylic acid grafted Epoxy [Binder 2] Bisphenol A type epoxy oligomer, lactone-modified epoxy containing polycaprolactone as an essential component and grafted with polycaprolactone [Binder 3.14] Polyoxyethylenated bisphenol A1 Polyoxypropylenated bisphenol A1 Terephthalic acid Eight types of resins were prototyped to be blended with a polyester main chain modified copolymer containing trimellitic acid as an essential component.

[Binder 5, 16, 171 Bisphenol A epoxy resin [Binder 8] Crosslinked epoxy resin made by partially crosslinking bisphenol A epoxy using aminocresol [Binder 9] Styrene and 2-ethylhexyl acrylate are essential constituents. Styrene-acrylic resin [Binder 20] Polyester containing ethylene glycol, 1,2-butylene glycol, terephthalic acid, isophthalic acid, and 2-methylterephthalic acid as essential components [Binder 21] Ethylene glycol, polyoxyethylated bisphenol A1 Polyester containing terephthalic acid, isophthalic acid, and trimellitic acid as essential constituents [Binder 22] Polyoxyethylenated bisphenol A1 Polyoxypropylenated bisphenol A1 Polyester containing terephthalic acid, isophthalic acid, and trimellitic acid as essential constituents In addition, the physical property values of the above resin are shown in Table 3. Further, toners were experimentally produced using the above resins and mixtures of the above resins as binders. Table 4 shows the evaluation results of toners using a single binder. Further, the mixing ratio, physical properties, and evaluation results are shown in Table 5. Note that trial production of each toner was performed by the following method.

First, 5 parts by weight of carbon black (Black Pearls L, manufactured by Capot Co., Ltd.) and 3 parts by weight of Nige 0 Shin dye (Bontron N-04 + manufactured by Orient Chemical Co., Ltd.) were added to the binder as a coloring agent, and the mixture was heated at 130°C using a pressure kneader. The mixture was melted and kneaded for 30 minutes to obtain a toner mass. The cooled toner mass was then processed into a coarse toner of about 2 mm using a Rotoplex mill.

Next, the crude toner was crushed and classified using a crushing classifier (IDs-3 type crushing classifier; manufactured by Nippon Pneumatic Industries) to obtain toner A having a particle size of 5 to 20 μm.

Furthermore, evaluations of fixability, void occurrence, etc. were performed as follows.

First, 95 parts by weight of resin-coated magnetite powder (average particle size 110 μm; Kanto Denka Gen) was used as a carrier, 5 parts by weight of toner was added to prepare a developer, and a flash fixing method was used. FACOM-67
This was done using a 15D laser printer. The thickness of the toner on the recording paper at this time was set to 10 to 15 μm. The setting conditions for the fixing device were such that a capacitor with a capacity of 160 μF was used, the charging voltage was 2+50 V, and this was applied to a flash lamp to cause the flash lamp to emit light, thereby fixing the toner on the paper.

In addition, for the evaluation of fixability, adhesive tape (Scotch Mending Tape, manufactured by Sumitomo 3M) was lightly applied, and a diameter of 100 mm was measured.
, a 20 mm thick iron cylindrical block is brought into close contact with the recording paper over the tape at a constant speed in the circumferential direction, then the tape is peeled off, and the ratio of the optical density after peeling to the optical density of the image before tape peeling is calculated. The fixability was evaluated as a percentage.

The optical density was measured using a PCM meter manufactured by Macbeth. In the evaluation table, the ratio of optical density after tape peeling is ◎ if it is 95% or more, and 0190 if it is 95 to 90%.
Up to 75% is marked with △, 75 to 30% is marked with ×, and less than that is marked with XX.

In addition, the occurrence of voids was visually evaluated.

Furthermore, regarding blocking properties, the toner was heated at 55°C.
After being left in a 30% R11 environment for 3 hours, the blocking state was visually evaluated. Regarding pulverization, the amount of toner processed using a jet pulverizer using each binder was compared with that of a toner using a jet pulverizer using bisphenol A diglycidyl ether polymer, which is commonly used as a binder for flash fixing toners, as a binder. Evaluation was made based on the throughput per unit time when pulverized.

The evaluation results are: ◎ for those that can process the same amount or more as bisphenol A diglycidyl ether polymer, ○ for those that have 90% or more of the processing fee, △ for 80 to 90%, and 50 to 8.
Those with a processing amount of 0% are indicated as ×, and those with a processing amount of less than that are indicated as XX.

As shown in Table 3.4, the melt viscosity and storage modulus at 200°C are 100 poise and 100 dyne/c, respectively.
Toner using a binder of nf or more has excellent void prevention ability, and on the other hand, the melt viscosity and storage modulus at 125°C are 5000 poise and 40000 dyn e/c.
Toners using the following binders have excellent fixing properties, and Na3. Nα1
, Nα8 satisfies the scope of the present invention in both low temperature melt viscoelasticity and high temperature melt viscoelasticity.

Furthermore, among the above binders, N has excellent void prevention ability.
α2. Nα3. Nct6. Nα16. which has excellent binding properties and blocking properties with Nα9 binder. Nα18°Nα20. Each of Nα21 was blended to make a binder, made into a toner, and its properties were evaluated (see Table 5).
.

[Effects of the Invention] As described above, according to the present invention, it is possible to obtain a toner having excellent void resistance and fixing properties, and excellent blocking resistance.

Table 1 Table 3 Table 2 Table 4

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of void generation. In the figure, 1... Toner 2...recording paper, 3...Flash, 4...Fixed image, 5...Void.

Claims (3)

[Claims] (1) In a toner using a binder, the binder has a surface tension of 30 dyne/c at 200°C.
m or less, melt viscosity is 100 poise or more, storage modulus is 1
00dyne/cm^2 or more, and the melt viscosity at 125°C is 5000 poise or less, and the storage modulus is 4000.
A toner characterized by using a binder having a physical property value of 0 dyne/cm^2 or less. (2) The binder has a melt viscosity of 30 poise or more at 200°C and a storage modulus of 50 dyne/cm^
2 or more, and the melt viscosity at 125°C is 3000 poise or less, and the storage modulus is 35000 dyne/cm^2
A binder with a melt viscosity of 120 poise or more at 200° C. and a storage modulus of 120 dyne/cm at 200° C.
^2 or more, and the melt viscosity at 125°C is 1000
0 poise or less, storage modulus is 100,000 dyne/c
The toner according to claim 1, characterized in that a binder having a molecular weight of m^2 or less is used as an essential component. (3) As the binder, a functional group that exhibits rubber-like elasticity at room temperature with respect to the first prepolymer or monomer that forms the main chain structure of the binder through polymerization and that is capable of reacting with the first prepolymer or monomer is selected from 1. 2. The toner according to claim 1, wherein the second prepolymer having 5 equivalents or more or a main chain modified copolymer into which a monomer which becomes the same as the second prepolymer upon polymerization is used.