JPH03139663A - Toner for heat fixing - Google Patents

Abstract

PURPOSE:To obtain the toner for heat fixing which does not generate an offset, allows the fixing of a toner image onto a recording material at a low temp. and is good in fixing as well by using release agents which exhibit a release property from a low temp. for a toner binder of low-temp. melting. CONSTITUTION:A thermoplastic resin with which the outflow initiation temp. in a flow tester is in a 75 to 105 deg.C range and the softening point is in a 90 to 150 deg.C range is used as the toner binder. At least one kind of the release agents having <=1.0X10<3> number average mol. wt. (Mn), <=2.5X10<2> weight average mol. wt. (Mw), <=3.0 Mw/Mn, and the m. p. ranging 60 to 120 deg.C are incorporated into the binder. The toner for heat fixing which does not generate the offset and allows the fixing of the toner image onto the recording material at a low temp. is obtd. in this way.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is applicable to electrophotography, electrostatic printing, magnetic recording, etc.
The present invention relates to a heat-fixing toner that fixes a visible image formed with the toner onto a recording material by heating.

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

However, in the above-mentioned hot roll fixing which has been widely used in the past, there is (1) a so-called wait time, which is a period during which the image forming operation is prohibited until the hot roller reaches a predetermined temperature.

(2) Maintaining the heating roller at an optimal temperature to prevent fixing failure and toner transfer to the heating roller due to fluctuations in temperature of the heating roller due to passage of the recording material or other external factors. It is necessary to
For this purpose, the heat capacity of the heating roller or heating body must be increased, which requires a large amount of electric power.

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

In order to achieve a fixing method that achieves excellent fixation of toner images on recording materials, prevention of offset, etc., and short wait time and low power consumption, much depends on the characteristics of the toner. Low-temperature fixing properties are required.

As a means to prevent the occurrence of offset phenomenon,
1) Those that perform fixing while applying a release oil such as silicone oil to the surface of a heated roller, 2) Those that use a high molecular weight polymer as the toner binder resin, and 3) Those that use a wax that has release properties in the toner. There are known methods for making it contain.

In the method (1), the above-mentioned oil etc. are heated, which generates an odor, and an extra device for supplying the liquid is required, resulting in disadvantages such as a complicated structure of the fixing device.

In method 2), although the non-offset property of the toner is improved, it is accompanied by an increase in the melting temperature of the toner, making it difficult to achieve low-temperature fixing.

Regarding method 3), for example, Japanese Patent Publication No. 52-3304
.

52-3305.57-52574.53-15565
5.58-12580 etc., there is a description of a toner containing a styrene resin and a specific mold release agent.

However, although the offset properties, particularly the high-temperature side offset phenomenon, have been improved, the fixing properties are insufficient, and the low-temperature fixing properties in particular have hardly been achieved. When these mold release agents are used with a binder that has low-temperature melting characteristics, the combination does not produce a mold release effect at lower temperatures, leading to deterioration of fixing properties due to the occurrence of low-temperature offset phenomenon. This is the reason why low-temperature fixability cannot be achieved.

[Problems to be Solved by the Invention] An object of the present invention is to solve the above-mentioned problems by providing a heating method that does not cause the offset phenomenon, fixes the toner image on the recording material at a low temperature, and provides good fixing. It provides fixing toner.

[Means and effects for solving the problems] The present invention provides a toner binder for heat fixing toner for fixing a visible image formed with a toner in electrophotography, electrostatic printing, magnetic recording, etc. onto a recording material by heating. Using a thermoplastic resin whose outflow start temperature in a flow tester is in the range of 75°C to 105°C and whose softening point is in the range of 90°C to 150°C, the number average molecular weight Mn is 1.0X103 or less, the weight average molecular weight ftMw or 2.5 XIO3 or less, Mw/M
The present invention relates to a toner for heat fixing, characterized in that it contains at least one type of release agent having n of 3.0 or less and a melting point mp in the range of 60 to 120°C.

One feature of the structure of the toner for heat fixing of the present invention is that as a toner binder, the outflow start temperature in a flow tester is in the range of 75 to 105 °C, and the softening point is in the range of 90 to 1
By using a toner using a thermoplastic resin having a temperature in the range of 50° C., the toner can be heated and fixed on a recording material with lower power consumption and lower temperature.

If the above-mentioned flow tester temperature of the toner binder is less than 75°C, the blocking properties of the toner will be significantly deteriorated and the storage stability will be impaired.On the other hand, if it exceeds 105°C, low-temperature fixing cannot be achieved and the toner will deteriorate. The power consumption required for fixing the image onto the recording material also increases.

On the other hand, if the softening point is less than 90°C, the toner tends to melt excessively during the heat fixing process, resulting in problems such as gloss on the image surface, seepage into the transfer paper, set-off, and image bleeding due to spread of the molten toner. A drawback arises. Further, offset to the fixing member becomes noticeable, and the effect of adding the release agent is significantly reduced.

On the other hand, if the softening point exceeds 150° C., although offset is improved, low-temperature fixing cannot be achieved and the power consumption required for fixing the toner to the recording material also increases.

The melting behavior of the toner binder was measured using an elevated flow tester (Shimadzu Flow Tester CFT-50) shown in Figure 1.
0 type) and was first molded using a pressure molder.
1. A load of 10 kgf was applied to sample 3 of 1 mm in diameter using plunger 1 at a heating rate of 5.0°C/min.
The sample was extruded from a nozzle 4 having a length of 1 mm, and the amount of descent of the plunger of the flow tester was thereby measured.

At this time, when the height of the S-curve in the flow tester's plunger drop-temperature curve (see Figure 2 flow tester outflow curve) is h, the temperature at h/2 is the softening point, and the sample starts flowing out. Let the temperature at the point be the outflow start temperature.

Another feature of the structure of the heat fixing toner of the present invention is that the number average molecular weight Mn is 1.
0x103 or less, weight average molecular weight Mw is 2.5 x 1
03 or less, Mw/Mn 3.0 or less, melting point mp 60~
By using a toner containing at least one type of 1llllt type agent that has a temperature range of 120°C, it is possible to heat and fix the toner on the recording material with lower power consumption and lower temperature without offset. be.

As a result of intensive research by the present inventors, it was found that for the low-temperature melting toner binder that enables low-temperature fixing, there is a need for a release agent that exhibits release properties at lower temperatures. It has become clear that the temperature is correlated with the melting point of the release agent, and that the lower the melting point is, the more advantageous it is to low-temperature fixing. However, when a release agent with a low melting point is used, adverse effects such as deterioration of the blocking properties of the toner and carrier filming when used as a two-component toner occur. Therefore, in the present invention, the molecular weight distribution of the mold release agent is determined so that the number average molecular weight Mn is 1.0
O" or less, weight average molecular weight Mw is 2.5 XIO" or less, Mw/Mn is 3.0 or less (preferably Mw/Mn =
It has been found that by making the molding material relatively sharp (2.0 or less), it is possible to improve the blocking properties, and it is also possible to obtain good properties that exhibit mold release properties at low temperatures and do not cause offset phenomena. .

In the present invention, the molecular weight distribution of the mold release agent is measured by GPC (gel permeation chromatography) under the following conditions.

(GPC measurement conditions) Equipment: LC-GPC150C (Waters Corporation) Column: GM) 16 (Toyo Soda) 60cm Column temperature: 140'C Measured under conditions of 3olv, o-dichlorobenzene or higher, and the molecular weight distribution of the sample is similar to the polyethylene standard. It was calculated from the relationship between the logarithm value of the calibration curve prepared using the sample and the number of counts.

Examples of the toner binder used in the present invention include boristyrene, polyα-methylstyrene, polyvinyltoluene, polychlorostyrene, styrene-butadiene copolymer, styrene-acrylic acid copolymer, and styrene-maleic anhydride copolymer. Polymers or copolymers of styrene or its substituted products such as coalescence, polyester resins, acrylic resins, xylene resins, ionomer resins, ketone resins, terpene resins, rosin, rosin-modified resins, maleic acid-modified phenolic resins, aromatic resins Petroleum resins, phenolic resins, aliphatic or alicyclic hydrocarbons, polyurethanes, polyamides, epoxy resins, polyvinyl alcohol resins, polyvinylpyrrolidone, silicone resins, etc. can be used alone or in combination.

The present invention is not limited to the toner binder made of the above-mentioned constituent materials, but the outflow start temperature in a flow tester is in the range of 75 to 105°C, and the softening point is in the range of 90 to!
Any thermoplastic resin with a temperature range of 50°C may be used.

The toner used in the present invention has a number average molecular weight Mn of 1.0X103 or less and a weight average molecular weight Mw of 2.5X
At least one release agent having IO3 or less, Mw/Mn 3.0 or less, and melting point ll1p in the range of 60 to 120°C is used in an amount of 0.1 to 20% by weight based on the toner. .

Examples include polyolefins such as polyethylene and polypropylene wax, paraffin waxes, and polyolefin waxes graft-modified with unsaturated fatty acids, styrene conductors, or unsaturated fatty acid esters.

The polyolefin is a homopolymer of α-olefin such as styrene, propylene, 1-butene, 1-hexene, 1-decene, 4-methyl-1-pentene, or 2 fff
It is a copolymer of α-olefins of i or more.

Furthermore, oxides of polyolefins are also included.

The unsaturated fatty acids or unsaturated fatty acid esters used to synthesize the graft-modified polyolefin include methacrylic acid and methyl methacrylate, ethyl methacrylate, propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, rhododendron methacrylate, and 2-ethyl methacrylate. Hexyl methacrylate, lauryl methacrylate-1, stearyl methacrylate, dodecyl methacrylate, phenyl methacrylate, dibutylaminoethyl acrylate, dibutylaminoethyl acrylate, 2-hydroxyethyl methacrylate, 2,2.2-trifluoroethyl methacrylate, methacrylic acid Methacrylates such as glycidyl, acrylic acid and methyl acrylate, edyl acrylate, propyl acrylate, n-butyl acrylate-1,
Inbutyl acrylate, n-octyl acrylate,
Lauryl acrylate-1, stearyl acrylate, dodecyl acrylate, 2-ethylhexyl acrylate, phenyl acrylate, 2-chloroethyl acrylate
I., 2-hydroxyethyl acrylate, cyclohexyl acrylate, dibutylaminoethyl acrylate, dibutylaminoethyl acrylate, dibutylaminoethyl acrylate, 2-ethoxy acrylate, 1.4
- Acrylates such as butanediol diacrylate, maleic acid, fumaric acid, itaconic acid, citraconic acid and monobutyl maleate, dibdermalate, monopropyl maleate, dipropyl maleate, monobutyl maleate, dibdermalate , di-2-ethylhexyl maleate, monobutyl maleate, diethyl fumarate, dibdermarate % di-2-ethylhexyl fumarate, monoethyl itaconate, diethyl fumarate, monoethyl citraconate, diethyl citraco Unsaturated dibasic acid esters such as
fffl or two or more types can be used simultaneously.

Examples of aromatic vinyl chlorides include styrene, 0-methylstyrene, m-methylstyrene, p-methylstyrene, α-methylstyrene, 2.4-dimethylstyrene, p-methylstyrene,
Ethylstyrene, p-n-butylstyrene, p-ter
t-butylstyrene, p-n-dodecylstyrene, p-
Phenylstyrene, p-chlorostyrene, etc. can be mentioned, and 1f weight or 21 weight or more of these can be used simultaneously.

As a method for graft modification, conventionally known methods can be used. For example, the above-mentioned polyolefin is reacted with an aromatic vinyl compound and an unsaturated fatty acid or an unsaturated fatty acid ester by heating in a solution or melt state in the atmosphere or under pressure in the presence of a radical initiator to obtain a graft-modified polyolefin. is obtained. Grafting with an aromatic vinyl compound and an unsaturated fatty acid or an unsaturated fatty acid ester may be carried out simultaneously or individually.

Examples of initiators used in the grafting reaction include benzoyl peroxide, dichlorobenzoyl peroxide, tert-butyl peroxide,
Examples include lauroyl peroxide, tert, -butylperphenylacetate, cumin verpivalate, azobisisobutyronitrile, dimedyl azoisobutyrate, dicumyl peroxide, and the like.

The toner used in the present invention is made of the above-mentioned constituent materials,
The number average molecule iMn is 1. In addition to a release agent having an OX of 103 or less, a weight average molecular weight Mw of 2.5X103 or less, a Mw/Mn of 3.0 or less, and a melting point mp in the range of 60 to 120℃, a release agent similar to the above-mentioned constituent materials with a melting point of 120℃ or higher is used. You may use a mixture of one or more molding agents.

When the toner used is a magnetic toner containing magnetic fine particles, the magnetic fine particles may be any material that exhibits magnetism or can be magnetized, such as metals such as iron, manganese, nickel, cobalt, and chromium, magnetite,
There are hematite, various ferrites, manganese alloys, and other ferromagnetic alloys, which have an average particle size of 0.05~
A fine powder of 5 μm can be used. The amount of magnetic fine particles contained in the magnetic toner is 1 of the total weight of the magnetic toner.
It is preferably 5 to 70% by weight (more preferably 25 to 45% by weight).

Further, various substances can be added to the toner used in the present invention for the purpose of coloring, controlling charge, etc. Examples include carbon black, iron black, graphite, nigrosine, metal complexes of monoazo dyes, ultramarine blue, phthalocyanine blue, banza yellow, benzidine yellow, quinacridone, and various lake pigments.

Alternatively, colloidal silica or the like may be contained in the toner in an amount of 10 to 40% by weight as a fluidity improver. Of course, this fluidity improver may be used by being mixed outside the toner, and the amount added in that case is 0.2 to 5% by weight (based on the weight of the toner).

[Example] Hereinafter, production examples of toners used in Examples and Comparative Examples of the present invention will be described, but they are not intended to limit the present invention in any way.

Example 1 Outflow start point measured by flow tester: 88.5°C, softening point: 1
Polyester (Tg 57.0°C) 100 at 15°C
parts by weight, 4 parts by weight of carbon black, 2 parts by weight of negative charge control agent, styrene and 2-ethylhexyl acrylate as graft components, number average molecular weight Mn 5.3x
102. Weight average molecular weight Mw 8.0x102, Mw
/Mn = 1.5, and after mixing 3 parts by weight of graft modified polyethylene wax with a melting point mp of 95°C, 2
After melt-kneading using an axial kneading extruder, the mixture was cooled, pulverized using an air flow pulverizer, and classified using an air classifier to obtain a black fine powder (non-magnetic toner) with an average particle size of about 12 μm. Toner A was obtained by adding and mixing 0.8 parts by weight of hydrophobic silica powder to 100 parts by weight of this toner.

300 g of resin-coated ferrite carrier was mixed with 30 g of this toner A to obtain developer A'.

An unfixed image of this Toner A was obtained using a modified NP-6650 (Canon ■ copier) from which the fixing device was removed. For recording purposes, commercially available copier paper 5 and Canon New Dry Paper (Canon sales ■) are used.
4 g/m2 paper was used.

For fixing tests on unfixed images, use Teflon as the upper roller.
Using a temperature-variable heat roller external fixing device with silicone rubber as the lower roller, the nip was 4 mm, the pressure between the upper and lower rollers was 0.4 kg/am in linear pressure, and the process speed was 5.
The temperature was controlled at 5°C intervals in a temperature range of 100°C to 230°C at a rate of 0 mm/sec. The fixed image obtained here is 5
Rubbing was performed with Silbon paper to which a load of 0 g/cm2 was applied, and fixing was started at a temperature at which the image density reduction rate before and after the rubbing was 7% or less. In addition, the offset test was evaluated by observing images and rollers.

As a result, the fixing start temperature was as low as 115°C, and the non-offset area was 110°C to 155°C, achieving low-temperature fixing.

(See Table 1) The anti-blocking properties were also good. The blocking resistance was determined by placing the toner in a dryer at 50°C.
Samples left in the sun were evaluated.

Example 2 6 A toner was obtained in the same manner as in Example 1, except that 2 parts by weight of the graft-modified wax used in Toner A and 1 part by weight of polyethylene wax with a melting point of 128° C. were used as release agents. Toner B was obtained by adding and mixing 0.8 parts by weight of hydrophobic silica to 100 parts by weight of this toner. This toner B was used in Example 1.
A developer was prepared in the same manner as above to obtain an unfixed image.

As a result of the fixing test, the fixing start temperature was 115°C and the non-offset region was 110-180°C, thus achieving low-temperature fixing.

(See Table 1) Also, the anti-blocking properties were good.

Comparative Example 1 A toner was obtained in the same manner as in Example 1, except that 3 parts by weight of polyethylene wax with a melting point of 128° C. was used as a release agent. Toner C was obtained by adding and mixing 0.8 parts by weight of hydrophobic silica to 100 parts by weight of this toner.

A developer was prepared from this Toner C in the same manner as in Example 1, and an unfixed image was obtained.

As a result of the fixing test, the fixing start temperature was 130° C., no non-offset region occurred, and no fixed region appeared. (Table-
1) Comparative Example 2 Number average molecule fiMn was used as a mold release agent 5. OX102,
Weight average molecular fiMw 1.7x 103. M+v/
Mn = 3.4, Example 1 for polyethylene wax
A toner was obtained in the same manner as in Example 1, except that 3 parts by weight of graft-modified polyethylene wax that had been subjected to the same graft modification treatment as in Example 1 was used. Toner D was obtained by adding and mixing 0.8 parts by weight of hydrophobic silica to 100 parts by weight of this toner.

A developer was prepared from this toner D in the same manner as in Example 1, and an unfixed image was obtained.

As a result of the fixing test, the fixing start temperature was 115°C and no offset was 110-150°C, achieving low-temperature fixing, but the blocking properties deteriorated, and blocking occurred in the sample left in a 50'C dryer for 3 days. . (See Table-1) Example 3 Outflow start point 95.0t, softening point 1 by flow tester
Styrene-butyl acrylate copolymer (at 34°C)
Tg! le, o°C) 100 parts by weight, 80 parts by weight of magnetic material, 2 parts of positive charge control agent, number average molecular weight Mn5, OX
102, weight average molecule fFzlJw 7.4X to2
After mixing linear paraffin wax synthesized by the Fischer-Tropsch method with Mw/Mn = 1.48, melting point mp, and 86°C, the mixture was melt-kneaded using a twin-screw kneading extruder, cooled, and pulverized using a pneumatic pulverizer. The mixture was classified using an air classifier to obtain a fine black powder (magnetic toner) with an average particle size of about 8 μm. Toner E was obtained by adding and mixing 0.6 parts by weight of hydrophobic silica to 100 parts by weight of this toner.

An unfixed image of this Toner E was obtained using a modified NP-1215 (Canon ■ copier) from which the fixing device was removed. The same recording material as in Example 1 was used, and the fixing test was conducted in the same manner. As a result, the fixing start temperature was 130
℃, the non-offset region was 120 to 220 degrees Celsius, and low-temperature fixing was achieved.

(See Table 1) The blocking properties were also good.

Example 4 A toner was obtained in the same manner as in Example 3, except that 2 parts by weight of the linear para-9 fin wax used in Toner E and 1 part by weight of polyethylene wax having a melting point of 128° C. were used as release agents. 0 parts of hydrophobic silica per 100 parts by weight of this toner.
．． Toner F was obtained by adding and mixing 6 parts by weight.

A fixing test was conducted using unfixed images obtained using this toner F in the same manner as in Example 1.

As a result, the fixing start temperature was 130°C, and the non-offset area was 1.
Low temperature fixing was achieved at 25-220°C.

(See Table 1) The blocking properties were also good.

Comparative Example 3 A toner was obtained in the same manner as in Example 3, except that 3 parts by weight of polyethylene wax having a melting point of 128° C. was used as a release agent. Toner G was obtained by adding and mixing 0.6 parts by weight of hydrophobic silica to 100 parts by weight of this toner.

A fixing test was conducted using unfixed images obtained using this toner G in the same manner as in Example 3.

As a result, the fixing start temperature was 145°C, which is higher than that of Example 0 3.4, and the non-offset area was also 160°C to 22°C.
The temperature shifted to the high temperature side of 0°C, and low temperature fixing could not be achieved.

Example 5 As in Example 1, Toner A was used as the toner to obtain an unfixed image.

The fixing test for the unfixed image was carried out using an external fixing device as shown in FIG. 3, which comprises a pressure member that is in pressure contact with a heating member and brings the recording material into close contact with the heating member via a film. As the material of the fixing film (5), a release layer of 10"m is made of polyimide film with fluororesin and conductive material added.
A coated endless film was used. As the pressure roller (8), silicone rubber is used, and the nip 3.
5 mm, and the process speed was 50 mm/sec.

The film drive consists of a drive roller (6) and a driven roller (
7) moves in the direction of the arrow without wrinkles due to the drive and tension. (The heating element (1) is a linear heating element with a low heat capacity, and the temperature is regulated by applying energy in a pulsed manner.) The temperature is controlled every 5 degrees Celsius in the range of 100 to 230 degrees Celsius, as in Example 1. Ta. As a result, the fixing start temperature was as low as 115°C, which was 100°C to 160°C in the non-offsera I region, and low-temperature fixing was achieved. Further, the wrapping around the fixing member was also good.

Table 1 Fixation test results [Effects of the invention] According to the heat fixing toner of the present invention, an offset phenomenon does not occur, a toner image is fixed to a recording material at a low temperature, and an image with good fixation is provided. be able to.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of an elevated flow tester. Second
The figure is a flow tester outflow curve, which shows the relationship between flow tester plunger drop amount and temperature. Third
The figure is an explanatory diagram of the fixing device.

Claims (1)

[Claims] 1) In toner for heat fixing, the toner binder has a flow start temperature of 75°C to 10°C in a flow tester.
A thermoplastic resin having a softening point of 90°C to 150°C and a number average molecular weight (Mn) of 1.5°C is used.
0x10^3 or less, weight average molecular weight (Mw) is 2.5x
10^3 or less, Mw/Mn 3.0 or less, and a melting point (mp) of 60 to 120°C.