JPH11305486A - Toner for developing electrostatic charge image - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide toner for developing an electrostatic charge image having good adhesiveness to an image support in flash fixation and both good anti- offsetting property and adhesiveness to an image support in heat roll fixation by using specified high softening point and low softening point polyester resins as the resin of toner. SOLUTION: The toner for both flash fixation and heat roll fixation consists of a resin and a colorant. The resin consists of a high softening point polyester resin having 130-150 deg.C softening point and a low softening point polyester resin having 80-125 deg.C softening point in a weight ratio of (80-30):(20-70). The high softening point component is a polymer resin consisting of a trior higher valent monomer, an arom. dicarboxylic acid and dialcohols including >=70 mol.% aliphatic dialcohol. The low softening point component is a polymer resin consisting of a trior higher valent monomer, an arom. dicarboxylic acid and dialcohols including >=70 mol.% arom. dialcohol.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrostatic image developing toner used in an image forming apparatus such as a copying machine and a printer.

[0002]

2. Description of the Related Art Conventionally, heat roll fixing has been favorably used due to its simplicity. However, in the heat roll fixing method, the fixing is performed by passing through the gap between the rollers at the fixing portion, so that there is a disadvantage that it is difficult to perform fixing on so-called pressure paper, thin paper, and even a three-dimensional object. ing.

On the other hand, although flash fixing requires a large amount of equipment as a heat source, it has an advantage that the image support as a fixing medium is not particularly limited.

[0004] By using a device having both surfaces, a device capable of simple fixing and fixing without limiting the support can be devised, but the performance required for the toner is greatly different between the two fixing methods. .

In the heat roll fixing method, there is a problem of offset with respect to the heat roll, and in order to solve this problem, various techniques for preventing offset by expanding a so-called molecular weight distribution have been proposed. A crosslinked resin is one of the resins that can exhibit this effect most. However, although the offset property can be improved by crosslinking the resin, when it is applied to flash fixing, the problem of poor adhesion to the image support arises because the resin has low meltability.

On the other hand, in the flash fixing method, although there is no problem of offset with respect to the heat roll, it is desired that the heat is instantaneously melted in a state where heat is applied. In order to exhibit this effect, a so-called linear polyester resin has been proposed. However, since this linear polyester has a low melt viscosity, there is a problem that an offset to the hot roll occurs at the time of heat roll fixing.

As described above, the heat-fusing characteristics required for the toners differ greatly between the two types of fixing systems. Therefore, a toner satisfying both of them has not been proposed in the past.

[0008]

SUMMARY OF THE INVENTION An object of the present invention is to provide good adhesion to an image support in flash fixing, good offset in heat roll fixing, and good adhesion to an image support. An object of the present invention is to provide a dual-purpose toner for developing an electrostatic image having the following.

[0009]

The object of the present invention is achieved by adopting the following constitution.

[1] A flash fixing and heat roll fixing electrostatic image developing toner which can be used in a system for fixing an image on an image support in both flash fixing and heat roll fixing. Is composed of a resin and a colorant, and the resin further comprises a high softening point polyester resin having a softening point of 130 to 150 ° C. and a low softening point polyester resin having a softening point of 80 to 125 ° C. Point component: low softening point component = 80-3
0:20 to 70 (weight ratio), the toner for developing an electrostatic image.

High-softening point polyester resin component: trivalent or higher polyvalent monomer component: aromatic dicarboxylic acid component: dialcohol, wherein aliphatic dialcohol is 70 mol% or more of all dialcohols. A polymer resin made of dialcohol.

A low-softening point polyester resin component: a trivalent or higher valent polyvalent monomer component: an aromatic dicarboxylic acid component: a dialcohol, wherein the aromatic dialcohol is 70 mol% or more of all dialcohols. A polymer resin made of dialcohol.

[2] The toner for developing an electrostatic image according to [1], which contains carnauba wax.

That is, the present inventors have conducted intensive studies, and as a result, have found that a polyester resin having a specific structure is suitable for achieving both heat roll fixability and flash fixability, and completed the present invention. That is what led to it.

In order to improve the heat roll fixing property, particularly the offset property, it is better to include a high softening point component. However, since a mere high softening point component causes a problem of deteriorating fixability in flash fixing, particularly in the present invention, an image is obtained by using a polyester resin using an aliphatic dialcohol as a main component in the dialcohol component. It has been found that the adhesiveness to paper as a forming support can be improved, and the offset property in heat roll fixing can be maintained without lowering the flash fixing property.

Further, an aromatic dialcohol is used as a main component of the dialcohol component as a low softening point component used to maintain the melting property required for flash fixing, and a polyester having a crosslinked structure is used. .
Although the mechanism of the manifestation of the effect by having this structure is unclear, as a result, it is necessary to maintain the flash fixing property without lowering the offset property in the heat roll fixing which is likely to occur due to the presence of the low softening point component. Thus, the present invention has been completed.

As the constituent components of the polyester resin used in the present invention, for example, those described in JP-A-1-202062 can be used.

(Polyester resin having a high softening point) The resin having a softening point of 130 to 150 ° C and the following is used.

Component: Trivalent or higher polyvalent monomer Examples of the trivalent carboxylic acid include the following.

1,2,4-benzenetricarboxylic acid,
2,5,7-naphthalenetricarboxylic acid, 1,2,4-
Naphthalenetricarboxylic acid, 1,2,4-butanetricarboxylic acid, 1,2,5-hexanetricarboxylic acid,
3-dicarboxyl-2-methyl-2-methylenecarboxypropane, 1,2,4-cyclohexanetricarboxylic acid, tetra (methylenecarboxyl) methane, 1,
Examples thereof include 2,7,8-octanetetracarboxylic acid and pyromellitic acid, and acid anhydrides thereof can also be used.

The following are examples of trihydric or higher alcohols: sorbitol, 1,2,3,6-hexane tetrol, 1,4-sorbitan, pentaerythritol, dipentaerythritol, tripentaerythritol,
2,4-butanetriol, 1,2,5-pentatriol, glycerol, 2-methylpropanetriol,
2-methyl-1,2,4-butanetriol, trimethylolethane, trimethylolpropane, 1,3,5-
Trihydroxymethylbenzene and the like can be mentioned.

Component: Aromatic dicarboxylic acid Representative examples include phthalic acid, isophthalic acid, terephthalic acid and the like.

Ingredients: dialcohols, wherein the total number of the dialcohols is at least 70 mol%, such as ethylene glycol, diethylene glycol, triethylene glycol, 1,2
-Propylene glycol, 1,3-propylene glycol, 1,4-butanediol, 1,3-butanediol, 1,2-butanediol, 1,4-butenediol, neopentyl glycol, 1,5-pentane glycol, 1,2-pentane glycol, 1,2-hexanediol, 1,4-hexanediol, 1,6-hexaneglycol, 1,4-cyclohexanedimethanol,
Examples include dipropylene glycol, polyethylene glycol, polypropylene glycol, polytetramethylene glycol, and the like.

Preferred aliphatic dialcohols include:
An aliphatic dialcohol having a branched chain, 1,2-propylene glycol, 1,3-propylene glycol,
1,2-butanediol, 1,3-butanediol, neopentyl glycol, 1,2-pentane glycol,
There are 1,2-hexanediol, 2,5-hexanediol, 1,4-hexanediol, 1,4-cyclohexanedimethanol and the like. It is preferable that the aliphatic dialcohol having a branch is contained in 50 mol% or more of the total aliphatic dialcohol.

Other dialcohols include polyoxypropylene-2,2-bis (4-hydroxyphenyl) propane and polyoxyethylene-2,2-bis (4
-Hydroxyphenyl) propane and other etherified bisphenols, bisphenol A, bisphenol Z, hydrogenated bisphenol A, and the like can be used.

Alternatively, a divalent carboxylic acid may be used in combination, but in that case, it is not more than 30 mol% in the total carboxylic acid.
Examples of the carboxylic acid include maleic acid, fumaric acid, citraconic acid, itaconic acid, glutacoic acid, succinic acid,
Adipic acid, sebacic acid, azelaic acid, malonic acid and the like can be mentioned, and these acid anhydrides can also be used.

(Low Softening Point Component) Those having a softening point of 80 to 125 ° C. are used.

Component: trivalent or higher polyvalent monomer Examples of the trivalent carboxylic acid include 1,2,4-benzenetricarboxylic acid, 2,5,7-naphthalenetricarboxylic acid, 1,2,4 -Naphthalene tricarboxylic acid, 1, 2,
4-butanetricarboxylic acid, 1,2,5-hexanetricarboxylic acid, 1,3-dicarboxyl-2-methyl-2
-Methylenecarboxypropane, 1,2,4-cyclohexanetricarboxylic acid, tetra (methylenecarboxyl) methane, 1,2,7,8-octanetetracarboxylic acid, pyromellitic acid, etc., and these acid anhydrides are also used. can do.

Examples of the trihydric alcohol component include sorbitol, 1,2,3,6-hexanetetrol,
4-sorbitan, pentaerythritol, dipentaerythritol, tripentaerythritol, 1,2,4-
Butanetriol, 1,2,5-pentatriol, glycerol, 2-methylpropanetriol, 2-methyl-1,2,4-butanetriol, trimethylolethane, trimethylolpropane, 1,3,5-trihydroxymethylbenzene And the like.

Component: aromatic dicarboxylic acid Phthalic acid, isophthalic acid, terephthalic acid and the like can be mentioned.

-Ingredient: dialcohol, dialcohol in which aromatic dialcohol is 70 mol% or more of all dialcohols. As aromatic dialcohol, polyoxypropylene-
Etherified bisphenols such as 2,2-bis (4-hydroxyphenyl) propane and polyoxyethylene-2,2-bis (4-hydroxyphenyl) propane, bisphenol A and bisphenol Z can be used.

The aliphatic dialcohols include ethylene glycol, diethylene glycol, triethylene glycol, 1,2-propylene glycol, 1,3
-Propylene glycol, 1,4-butanediol,
1,3-butanediol, 1,2-butanediol,
1,4-butenediol, neopentyl glycol,
1,5-pentane glycol, 1,2-pentane glycol, 1,2-hexanediol, 1,4-hexanediol, 1,6-hexane glycol, 1,4-cyclohexanedimethanol, dipropylene glycol, polyethylene glycol, You may use polypropylene glycol, polytetramethylene glycol, etc.

Further, a divalent carboxylic acid may be used in combination. In this case, maleic acid, fumaric acid, citraconic acid, itaconic acid, glutacoic acid, phthalic acid, isophthalic acid, terephthalic acid, succinic acid, adipic acid, sebacic acid, azelaic acid, malonic acid, n-dodecylsuccinic acid,
Examples thereof include n-dodecenylsuccinic acid, isododecylsuccinic acid, isododecenylsuccinic acid, n-octylsuccinic acid, and n-octenylsuccinic acid. These acid anhydrides can also be used.

In particular, divalent carboxylic acids suitable for use in the low softening point component include n-dodecyl succinic acid, n-dodecenyl succinic acid, isododecyl succinic acid, and the like.
Isododecenyl succinic acid, n-octyl succinic acid, n-
It is preferable to use a carboxylic acid having a side chain having 2 to 20 carbon atoms, such as octenyl succinic acid, or an acid anhydride thereof. Although the reason is not clear, the occurrence of entanglement of the molecular chains improves the adhesiveness to the image support, and the fixing rate can exhibit the effect of improving both the flash fixing and the heat roll fixing. That's why.

The mixing ratio of the high softening point component and the low softening point component is as follows: high softening point component: low softening point component = 80-30: 20-70
(Weight ratio) is good, and the effect of the present invention can be obtained in this range.

A more preferable range is as follows: high softening point component: low softening point component = 70 to 30:30 to 70
(Weight ratio).

When there are many components having a high softening point, the flash fixability decreases, and when there are many components having a low softening point, the fixability in heat roll fixing decreases.

The measurement of the softening point in the present invention indicates a value measured using a Koka type flow tester (manufactured by Shimadzu Corporation). Specifically, the Koka type flow tester “CFT-
500 "(manufactured by Shimadzu Corporation) and the diameter of the dice
mm, length 1 mm, load 20 kg / cm ² , heating rate 6
The temperature corresponding to 1/2 of the height from the outflow start point to the outflow end point when a 1 cm ³ sample is melted out under the conditions of ° C / min is shown as a softening point.

As other components constituting the toner, it is preferable to use an aliphatic bisamide wax, a carnauba wax or the like as a wax if necessary in order to prevent offset of the toner at the time of heat roll fixing.
In particular, carnauba wax is preferably used. As carnauba wax, refined carnauba No. 1, refined carnauba 2
No. etc. can be used. The added amount is 1 to 5% by weight in the toner.

This wax precipitates on the surface because of its low melt viscosity in flash fixing. As a result, there is also an effect in that the glossiness of the fixed surface is increased and the density of the fixed image tends to be improved.

The colorant used in the present invention is not particularly limited, and various known pigments used for toner,
Dyes can be used.

Examples of the black color include carbon black,
Various carbons such as grafted carbon, furnace black and thermatomic carbon, and inorganic pigments such as magnetite and ferrite are usually used. For color toners, C.I. I. Pigment Blue 15, C.I.
I. Pigment Blue 15: 2, C.I. I. Pigment Blue 15: 3, C.I. I. Cyan pigments such as CI Pigment Blue 16, C.I. I. Pigment Red 2, C.I. I. Magenta pigments such as CI Pigment Red 3, C.I. I. Pigment Yellow 12, C.I. I. Pigment Yellow 17 and the like can be used.

Also, a positive charge control agent such as a metal salt of naphthenic acid or higher fatty acid as an antistatic agent, a quaternary ammonium salt, various metal complex salts, and a negative charge control agent such as an organic complex salt or chlorinated polyester are required. Can be used according to

The flash fixing conditions are not particularly limited as long as the toner can be sufficiently fixed. A typical example is a xenon lamp using an applied voltage of 1000 to 2500 V. flash energy: (1/2) energy represented by the CV ² is 100
About 1000J can be used (however, C
= Capacitor capacity of lamp, V = voltage applied to lamp).
The light emission time is about 500 to 2000 μsec.

On the other hand, if an example of the heat roll fixing method is shown, the inside of a metal cylinder made of iron, aluminum, or the like, whose surface is coated with tetrafluoroethylene or polytetrafluoroethylene-perfluoroalkoxyvinyl ether copolymer, etc. It is formed of an upper roller having a heat source and a lower roller formed of silicone rubber or the like. Specifically, it has a linear heater as a heat source,
The surface temperature of the upper roller is heated to about 120 to 200 ° C. In the fixing section, pressure is applied between the upper roller and the lower roller to deform the lower roller and form a so-called nip. The nip width is 1 to 10 mm, preferably 1.5 to 7 mm. Fixing linear speed is 40mm / s
ec to 400 mm / sec is preferable. When the nip is narrow, heat cannot be uniformly applied to the toner, causing uneven fixing. On the other hand, if the nip width is large, the melting of the resin is promoted, which may cause a problem that the fixing offset becomes excessive.

[0046]

EXAMPLES The present invention will be described below in detail with reference to examples, but embodiments of the present invention are not limited thereto. In the text, “parts” means “parts by weight”.

The high softening point component and the low softening point component were separately prepared and mixed.

(Preparation of high softening point component resin) A polyester resin having the composition shown in the following table was prepared. In the reaction, the raw materials other than the trivalent carboxylic acid are thermometer, stirrer, refluxer,
The mixture was placed in a reaction vessel equipped with a nitrogen inlet tube, dibutyltin oxide (20 to 40 mg) was added, and the mixture was reacted at 200 ° C. After that, only trivalent carboxylic acid was added, and the reaction was continued. The reaction time was controlled while measuring the softening point.

[0049]

[Table 1]

(Preparation of low softening point component resin) A polyester resin having the composition shown in the following table was prepared. In the reaction, the raw materials other than the trivalent carboxylic acid are thermometer, stirrer, refluxer,
The mixture was placed in a reaction vessel equipped with a nitrogen inlet tube, dibutyltin oxide (20 to 40 mg) was added, and the mixture was reacted at 200 ° C. After that, only trivalent carboxylic acid was added, and the reaction was continued. The reaction time was controlled while measuring the softening point.

[0051]

[Table 2]

The softening points of the above resins are shown below.

[0053]

[Table 3]

Further, the above-mentioned resins were mixed at the following ratio (weight ratio) to prepare a resin.

[0055]

[Table 4]

(Example of Toner Production) To 100 parts of the above resin, 10 parts of carbon black (Mogal L manufactured by Cabot Corporation), 3 parts of purified carnauba wax No. 1, and 2 parts of stearyl bisamide wax were added, and mixed with a Henschel mixer. Melt kneaded, crushed and classified to have a volume average particle size of 8.5.
μm colored particles were prepared. 0.6 parts by weight of hydrophobic silica was added to the colored particles and mixed with a Henschel mixer to obtain a toner.

A list is shown below.

[0058]

[Table 5]

A carrier coated with a styrene-acrylic resin was added to these toners to prepare a developer having a toner concentration of 5%. Next, an image was formed using this image by using a digital copying machine Konica 7050 manufactured by Konica Corporation, and the unfixed image was used to evaluate the flash fixing property and the hot roll fixing property. These fixing conditions are shown below. Note that 110 kg paper was used as the paper to be used. The printed image is a character image having a pixel ratio of 5%.

Flash Fixing Conditions The conditions for setting the flash fixing device were as follows. A capacitor having a capacity of 160 μF was used, the charging voltage was set to 2050 V, and the flash lamp was applied to the flash lamp. The light emission time was 1000 μsec.

Heat Roll Fixing Conditions As the heat roll system, the surface was made of tetrafluoroethylene-
A cylindrical iron having a 30 mm diameter heater built in the center part coated with a perfluoroalkyl vinyl ether copolymer is used as an upper roller, and a silicone rubber whose surface is similarly coated with a tetrafluoroethylene-perfluoroalkyl ether copolymer is used. The constructed lower roller of 30 mm diameter is used. The linear pressure was set at 0.8 kg / cm, and the nip width was 4.3 mm. Using this fixing device, the printing linear velocity was set to 250 mm / sec. Note that a cleaning mechanism for the fixing device is not provided.

The surface temperature of the fixing unit is variable (150 to
230 ° C.).

(Evaluation Method) Using the above-mentioned fixing device, evaluation of flash fixing property and hot roll fixing property was performed.

Using the fixed image, a scotch mending tape (manufactured by Sumitomo 3M) was lightly stuck on the image, and a cylindrical weight having a diameter of 5 cm and a weight of 1200 g was placed thereon and left for 1 minute. Next, the tape was peeled at a constant speed at an angle of about 180 °, and the state of adhesion to the tape was visually observed, and judged according to the following criteria.

A: No attached matter B: Slight attached matter is observed C: Characters are thin but not legible D: Characters legible The practical allowable range is "B" or more.

Heat Roll Fixability Using the above-mentioned fixing device,
The temperature was raised from 150 ° C. in steps of 5 ° C., and the occurrence of offset was evaluated. The offset occurrence temperature on the low temperature side and the offset occurrence temperature on the high temperature side are measured, and the difference is determined as a “non-offset region”. Further, at a fixing temperature of 190 ° C., the fixing property was evaluated in the same manner as the flash fixing property evaluation described above. The criteria are the same.

The results of the above evaluations are shown below.

[0068]

[Table 6]

As shown in the above results, it is understood that the toner of the present invention satisfies both the flash fixing property and the hot roll fixing property.

[0070]

According to the present invention, a dual-purpose static toner having good adhesiveness to an image support in flash fixing, good offset in heat roll fixing and good adhesiveness to an image support. A charge image developing toner can be provided.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Hiroko Nishimori 2970 Ishikawacho, Hachioji-shi, Tokyo Konica Corporation

Claims (2)

[Claims] 1. An electrostatic image developing toner for flash fixing and heat roll fixing which can be used in a method for fixing an image on an image support in both flash fixing and heat roll fixing. A high-softening point polyester resin having a softening point of 130 to 150 ° C and a low softening point polyester resin having a softening point of 80 to 125 ° C. Ingredient: low softening point component = 80-3
0:20 to 70 (weight ratio), the toner for developing an electrostatic image.・ High softening point polyester resin component: trivalent or higher polyvalent monomer component: aromatic dicarboxylic acid component: dialcohol, from dialcohol whose aliphatic dialcohol is 70 mol% or more in all dialcohols Polymer resin. -Low softening point component polyester resin Component: trivalent or higher polyvalent monomer Component: aromatic dicarboxylic acid Component: dialcohol, from dialcohol whose aromatic dialcohol is 70 mol% or more in all dialcohols Polymer resin. 2. The toner according to claim 1, further comprising carnauba wax.