JPH03229264A - Heat fixable toner - Google Patents

Abstract

PURPOSE:To obtain the toner having a wide fixable range by incorporating a bivalent or higher valency org. metal compd. into the above toner at 0.2 to 10 pts. wt. per 100 pts. wt. binder resin consisting of a linear polyester resin having 5 to 60 mg KOH/g acid value and a nonlinear polyester resin having <5 mg KOH/g acid value. CONSTITUTION:The binder resin consists of the linear polyester resin having 5 to 60 mg KOH/g acid value and the nonlinear polyester resin having <5 mg KOH/g acid value. The bivalent or higher valency org. metal compd. is incorporated into the toner at 0.2 to 10 pts. wt. per 100 pts. wt. such binder resin. Such heat fixable toner is used and a fixing film 18 is transferred by being pressed to a heating element 14 subjected to temp. control to a desired temp. controlled by a temp. detecting element 17. The unfixed toner 23 on a transfer material 22 is introduced to a fixing part and is heated to obtain a fixed image. The heat fixable toner which has the excellent fixability and offset resistance, is wide in the fixing temp. range and allows the reduction of energy is obtd. in this way.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a heat-fixable toner particularly suitable for a heat-fixing method among developers used in electrophotography, electrostatic printing, magnetic recording, and the like.

[Prior Art] Conventionally, methods for fixing a toner visible image on a recording material include a method of fixing by heating and melting with a heater or a heated roller, a method of fixing by applying pressure, and a method of softening or fixing a toner binder with an organic solvent. There are methods of melting and fixing, but the most common method at present is a method of melting and fixing by heating.

On the other hand, as copying operations become more efficient and energy efficient in recent years, and copying machines become smaller, faster, and more efficient, toners that can be fixed at lower temperatures are required for use in heat fixing methods.

Low molecular weight polyester resin is attracting attention as a material suitable for low-temperature fixing toner. An attempt to use polyester resin as binder for toner was made in Japanese Patent Publication No. 46-1268.
Publication No. 0 (IJsP, No. 3590000) 1 Special Publication Sho 5
Many proposals have been made, such as Publication No. 2-25420 ([JSP, No. 3681106). However, if the molecular weight of the resin is reduced in order to achieve fixing at a lower temperature, the melt viscosity will decrease. A so-called offset occurs in which the upper part is also fused.

To prevent offset in toners whose main binder is polyester resin, Japanese Patent Publication No. 52-25420
As typified by the above publication, it has been proposed to mix trivalent or higher valent polyols and polyacids to make the polymer nonlinear and improve its viscoelasticity to improve offset properties during fixing. If non-linearity is advanced until sufficient offset resistance is achieved, the fixing point will rise, which is disadvantageous for toners intended for lower temperature fixing.

Also, as proposed in Japanese Patent Application Laid-Open No. 59-9669,
There has also been an attempt to prevent offset by mixing polyvalent metal compounds and creating a cross-linked structure with metal ions, causing interaction between polymer chains and changing their melt viscoelasticity. However, since polyvalent metal compounds have lower specific resistance than resins, the charging ability of the toner decreases. For this reason, when offset prevention is sought only by crosslinking with a polyvalent metal compound, the amount added tends to be large and the developability of the toner tends to deteriorate.

As described above, low-temperature fixing properties and anti-offset properties are contradictory performances, and it is extremely difficult to achieve both. As a means to improve this, as proposed in JP-A No. 64-15755, there is a method of blending a low molecular weight polyester to achieve low temperature fixing with a high molecular weight polyester to achieve offset resistance. There is. This makes it possible to achieve low-temperature fixing while maintaining offset resistance compared to conventional polyester.

However, in order to achieve lower temperature fixing, the blended low molecular weight polyester must have a fairly low melting point, which lowers the glass transition point and causes the toner to block during storage or in high temperature environments. Undesirable phenomena occur.Furthermore, due to the low melting point resin, continuous use in a copying machine or use in a high temperature environment may cause inconveniences such as toner fusing on the toner carrier or photoreceptor due to heat. There were many points.

Furthermore, Japanese Patent Application Laid-Open No. 60-4947 proposes a toner in which an organometallic compound is added to a mixture of linear polyester and non-linear polyester resins to cause crosslinking. However, in this case, the crosslinking effect acts on both linear and non-linear polyester resins (therefore, the non-linear polyester becomes polymerized, which is insufficient when aiming at lower temperature fixing). It is.

[Problems to be Solved by the Invention] The objects of the present invention are to achieve sufficient fixation at a lower temperature, to enable low energy use, to sufficiently prevent offset, and to
The purpose of the present invention is to provide a toner with a wide fixable area. A further object of the present invention is to provide a toner that has an acceptable agglomeration temperature and that does not block during storage and use. A further object of the present invention is to provide a toner that does not fuse on a toner carrier or photoreceptor under any environment and under any usage conditions. A further object of the present invention is to provide a toner with excellent development characteristics that provides a sufficiently high image density, sharp resolution, and no background fog. A further object of the present invention is to provide a toner that is easy to manufacture, has good manufacturing efficiency (allows for stable production, and is low in cost).

[Means and effects for solving the problem] As a result of intensive studies, the present inventors found that the binder resin is a linear polyester resin having an acid value of 5 to 60 mgKOH/g, and a linear polyester resin having an acid value of 5 mgKOH/g.
It is characterized by comprising a non-linear polyester resin having an acid value of less than g, and containing 0.2 to 10 parts by weight of an organometallic compound having a valence of 2 or more based on 100 parts by weight of the binder resin. It has been found that the above object can be achieved by using a heat fixable toner. The details will be explained below.

In the present invention, an organometallic compound having a valence of 2 or more is added to a mixture of a linear polyester having an acid value of 5 to 60 mgKOH/g and a non-linear polyester having an acid value of less than 5 mgKOB/g. It is unique in that it only crosslinks.

In order to achieve both low-temperature fixing and offset resistance, it is effective to use a resin that is a blend of linear polyester with low-temperature fixing properties and non-linear polyester with offset-resistant properties. Measures are taken to lower the molecular weight and melting point of the linear polyester. However, at this time, the linear polyester component may cause the toner to fuse onto the toner carrier or photoconductor, or cause blocking in high-temperature environments.To prevent this, 5 to 60 mgKOH/g of linear polyester It was proposed that linear polyester be crosslinked by giving it an acid value and adding an organometallic compound with a divalent or higher valence. The crosslinking effect increases the molecular weight of linear polyester and increases its thermal strength, which can prevent fusion and blocking. Since the molecular weight increases without progress, low-temperature fixability is not impaired compared to crosslinking of non-linear polyester.

In the present invention, linear polyester and non-linear polyester are dissolved and mixed in a solvent such as xylene or toluene, the solvent is removed to obtain a blended resin, and then an organometallic compound is added and melt-kneaded to perform a crosslinking reaction. There is a way to do it. Alternatively, there is a method in which a linear polyester, a non-linear polyester, and an organometallic compound are mixed in a Henschel mixer or the like, and then melt-kneaded to perform a crosslinking reaction. However, a method in which linear polyester and an organometallic compound are melt-kneaded, a crosslinking reaction is performed, and then mixed with non-linear polyester is not preferred. Although the reason is unknown, this is because there is a phenomenon in which the developing characteristics are poor when turned into toner. As mentioned above, in the present invention, the crosslinking reaction is carried out in the presence of linear polyester and non-linear polyester at the same time, but the non-linear polyester used in the present invention has an acid value of 5 mgKOf (/g Since it is less than 10%, there is no substantial crosslinking even in the presence of an organometallic compound, and there is no increase in molecular weight, so low-temperature fixing properties are not impaired.

The linear polyester used in the present invention can be produced by condensation polymerization using a difunctional carboxylic acid and a diol using a conventional method.

Bifunctional carboxylic acids are divalent carboxylic acids, divalent carboxylic acid anhydrides, and derivatives thereof such as esters, such as terephthalic acid, isophthalic acid, phthalic acid, diphenyl-p-p-dicarboxylic acid, Naphthalene-2,7-
Dicarboxylic acid, naphthalene 2,6-dicarboxylic acid, diphenylmethane-pp-dicarboxylic acid, benzophenone-4,4'-dicarboxylic acid, 1,2-diphenoxyethane-pp-dicarboxylic acid, maleic acid, fumaric acid , glitaric acid, cyclohexanecarboxylic acid, succinic acid, malonic acid, adipic acid, or anhydrides and esters thereof.

Further, as diol components, ethylene glycol, diethylene glycol, triethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol,
Alkylene glycols such as 1,4-butanediol, cyclohexane dimetatool, neopentyl glycol, 1,4-butynediol, bisphenol A1 hydrogenated bisphenol A1 polyoxypropylene (2,0)-2,
2-bis(4-hydroxyphenyl)propane, polyoxyethylene(2,0)-2,2-bis(4-hydroxyphenyl)propane, 2,2'-(1,4-)unilenebisoxy)bis Ethanol, 1,1'-dimethyl-
2,2'-(1,4-phenylenebisoxy)bisethanol, 1,1.4',1'-tetramethyl-2,2'
-(1,4-phenylenebisoxy)bisethanol and the like.

Further, the non-linear polyester used in the present invention is 3
It can be produced by condensation polymerization of at least one type of polycarboxylic acid having a valence or higher or a polyol having a valence of 3 or higher, a difunctional carboxylic acid, and a diol by a conventional method.

Examples of trivalent or higher polycarboxylic acids include trimellitic acid, pyromellitic acid, cyclohexanetricarboxylic acids, 2,5.7-naphthalenetricarboxylic acid, 1,2.
4-naphthalenetricarboxylic acid, 1, 2.4-butanetricarboxylic acid, 1,2.5-hexanetricarboxylic acid, 1.3-dicarboxyl-2-methylenecarboxylpropane, 1.3-dicarboxyl-2-methyl- 2-
Methylenecarboxylpropane, tetra(methylenecarboxyl)methane, 1,2,7.8-octanetetracarboxylic acid, and their anhydrides and esters can be used.

Examples of trivalent or higher polyols include sorbitol,
1,2,3.6-hexanethetol, 1,4-sorbitan, pentaerythritol, dipentaerythritol,
Tripentaerythritol, sucrose, 1,2,4-mentatriol, glycerin, 2-methylpropanetriol, 2-methyl-1,2,4-butanetriol, trimethylolethane, trimethylolpropane, 1,3
．． 5-trihydroxymethylbenzene and the like can be used.

Furthermore, the bifunctional carboxylic acids and diols used in the nonlinear polyester can be those mentioned above.

The linear polyester used in the present invention has an acid value of 5 to 60 m.
gKOf (/g. If the acid value is less than 5 mgKOH/g, the crosslinking reaction will not substantially occur, and if the acid value is less than 60 mg
If it exceeds 1/g (KO), crosslinking will proceed too much, resulting in poor fixing and poor environmental properties of the resin. The non-linear polyester has an acid value of less than 5 mgKOH/g. When the acid value is 5 mgKOH/g or more, the crosslinking reaction proceeds due to the presence of the organometallic compound, resulting in problems such as an increase in the fixing temperature when a toner is formed. The acid value is measured according to JISK-0070.

Examples of the organometallic compound used in the toner of the present invention include organic salts or complexes containing divalent or higher valent metals. Effective metal species include 82゜Ba, Ca,
Cd, Go, Cr, Cu, Fe, Hg, Mg,
Examples include multivalent materials such as Mn, NiPb, Sn, Sr, and Zn.

As organometallic compounds, carboxylates, alkoxylates, organometallic complexes, and chelate compounds of the above metals are effective; examples include zinc acetate, magnesium acetate, calcium acetate, aluminum acetate, magnesium stearate, calcium stearate, and stearin. acid aluminum, aluminum isopropoxide, aluminum acetylacetate, iron (If) acetylacetonate,
Examples include chromium 3.5 di-tert-butylstearate, and acetylacetone metal complexes and salicylic acid metal salts are particularly preferred. The amount added should not exceed 10% by weight based on the binder resin in order to avoid the adverse effects mentioned above. Moreover, if it is less than 0.2%, the substantial effect disappears.

Further, as the toner binder of the present invention, other known binder resins may be mixed and used within a range that does not impair the performance of the present invention. Examples include epoxy resins, styrene-acrylic copolymers, styrene-butadiene copolymers, and the like.

A charge control agent, a colorant, and a fluidity modifier may be added to the toner of the present invention as necessary, and the charge control agent and fluidity modifier are mixed (externally added) with the toner and used. It's okay. Examples of charge control agents include metal-containing dyes and nigrosine, conventionally known dyes and pigments can be used as colorants, and colloidal silica, fatty acid metal salts, etc. can be used as fluidity modifiers. be.

Furthermore, if it is desired to obtain a magnetic toner, magnetic fine particles may be added to the toner. The magnetic substance may be any material that exhibits magnetism or can be magnetized, such as fine metal powders such as iron, manganese, nickel, cobalt, and chromium, various ferrites, alloys and compounds such as manganese, and other ferromagnetic alloys such as magnetite. It is possible to use conventionally known magnetic materials such as .

Furthermore, polyolefins such as low molecular weight polyethylene and low molecular weight polypropylene may be added to the toner in order to improve the releasability from the heat fixing roll.

[Example] Production examples of linear polyester and non-linear polyester used in the present invention are shown below.

<Production Example 1> Put four of them into a flask, set a stirrer, condenser, thermometer, and gas inlet tube, and place them in a mantle heater. Furthermore, dibutyltin oxide was added at 0.0% relative to the total acid components.
05 mol% was added, and the mixture was heated and stirred at 210°C. The reaction proceeded while removing the reaction water and measuring the acid value. When the acid value reached 45, the reaction product was cooled to room temperature to obtain a linear polyester resin A.

Production Example 2> A linear polyester resin B having an acid value of 35 was obtained from the above monomer in the same manner as in Production Example 1.

<Production Example 3> A linear polyester resin C having an acid value of 40 was obtained from the above monomer in the same manner as in Production Example 1.

<Production Example 4> The pressure in the system was adjusted in the same manner as in Production Example 1, and a linear polyester D having an acid value of 3 was obtained from the above monomer.

<Production Example 5> The reaction time was adjusted in the same manner as in Production Example 1, and a linear polyester resin E having an acid value of 70 was obtained from the above monomer.

<Production Example 6> A non-linear polyester resin F having an acid value of 3 was obtained from the above monomer in the same manner as in Production Example 4.

<Production Example 7> In the same manner as in Production Example 4, a non-linear polyester resin G having an acid value of 2 was obtained from the above monomer.

Production Example 8> In the same manner as in Production Example 4, a non-linear polyester resin H having an acid value of 1 was obtained from the above monomer.

<Production Example 9> Using the same method as Production Example 1, adjusting the reaction time, Production Example 7
A non-linear polyester resin (2) having an acid value of 10 was obtained from the monomer.

Examples will be described below, and evaluations regarding fixing, fusion, and blocking were performed as follows.

<Fixing> Take out the fusing unit of the Canon copier FC-5,
A separate fuser A is prepared that has been modified so that the pressure between the upper and lower rollers is 0.30 kg/cm in linear pressure, the nip width is 3.0 mm, the linear speed is 60 mm/sec, and the temperature of the upper roller can be varied from 100 to 270°C. did. Similarly, a modified fuser B of Canon copier NP-7550 (pressure between upper and lower rollers 2.5 kg/cm, nip width 6.0 mm, linear speed 450 mm/see, upper roller temperature 100-270
℃ (variable) was prepared. Furthermore, a fixing device C shown in FIG. 1 was prepared.

The fixing device shown in FIG. 1 will be briefly explained.

In the figure, reference numeral 14 denotes a low heat capacity linear heating element that is fixedly supported by the device and has a thickness of 1. omm, width 10mm, length 24
Resistance material 16 is placed on a 0mm alumina substrate 15 with a width of 1.0m.
It is coated with a thickness of 1.m and is energized from both ends in the long plane direction. The current is applied to a desired temperature controlled by the thermometer 17 using a pulse-like waveform of DC 100V with a period of 20m5ec.
A pulse corresponding to the amount of energy emitted is given by changing the pulse width. Such a pulse width is 0.5 m5ec~
5 m5ec. The fixing film 18 moves in the direction of the arrow in the figure while coming into contact with the heating body 14 whose energy and temperature are controlled in this manner. This fixing film has a thickness of 20 pm.
It is an endless film made of polyimide coated with a release layer of 10 μm, which is made by adding a conductive material to PTFE on the image contact side. The film is driven by the driving roller 19 and the driven roller 20 and tension to move the film in the direction of the arrow without wrinkles.

Reference numeral 21 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 5 kg and rotates in pressure contact with the film.

The unfixed toner 23 on the transfer material 22 is guided to the fixing section by the entrance guide 24, and a fixed image is obtained by the above-mentioned heating.

The conditions of the fixing device are the same as those of the fixing device A.

In the fixing test, the set temperature of each fixing device was varied, and an unfixed image was passed through the paper at each set temperature to evaluate fixing properties and offset properties. Regarding fixability, 50g/c on the fixed image
The temperature at which the density reduction rate of the image is 7% or less was determined as the fixing point by rubbing with Silbon paper with a load of Judging by how dirty it is.

For positively charged toner, use a Canon copier NP-55.
40. In the case of negatively chargeable toner, use a modified NP-5540 machine to continuously print 5,000 sheets in a high-temperature environment (32.5°C, 90%). I observed that the toner fused.

Blocking> The toner was left in an atmosphere at 50° C. for 3 days, and the state of blocking was visually confirmed.

Example 1 A mixture of the above formulation was melt-kneaded using a twin-screw extruder, cooled, and crushed and classified to obtain a black fine powder with an average particle size of 10.5 μm. Further, 0.4 parts of amino-modified silicone oil-treated silica fine powder was externally added to 100 parts of the black fine powder to obtain a positively chargeable toner.

Regarding fixing properties, evaluation was performed using fixing device A. The fixing point was 125°C, high temperature offset occurred from 200°C, and the fixable temperature range was 75°C, which was very excellent. No fusion was observed, and there was no problem with blocking.

Examples 2-5. and Comparative Examples 1 to 4 The prescriptions are summarized in Table 1, and the evaluation results are summarized in Table 2.

(The following is a margin) [Effects of the Invention] The toner of the present invention has excellent fixing properties and anti-offset properties, has a wide fixing temperature range, and can use low energy.

Further, the toner of the present invention has excellent blocking properties, development properties, etc., and can stably supply high-quality images.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram of a fixing device used in an embodiment of the present invention.

Claims (1)

[Claims] (1) The binder resin is composed of a linear polyester resin having an acid value of 5 to 60 mgKOH/g and a non-linear polyester resin having an acid value of less than 5 mgKOH/g, based on 100 parts by weight of the binder resin. A heat-fixable toner comprising 0.2 to 10 parts by weight of an organic metal compound having a valence of 2 or more.