JPH09304966A - Developer and manufacture thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an electrophotographic developer which is excellent in offset-resistance, keeping quality, fluidity and fixability by providing a wax internal added resin manufacturing process of manufacturing resin containing first wax and a melting and mixing process of melting and mixing second wax having a specified viscosity. SOLUTION: As a wax internal added resin manufacturing process, first wax is dispersed with a polymerizing monomer for forming binder resin in a solvent, and the dispersed matter is mixed and polymerized in a polymerizing process ST1. Subsequently, resin manufactured in the wax internal added resin manufacturing process is molten and mixed together with second wax having a higher viscosity than that of the first wax and a coloring agent while heating in the melting and mixing process ST2. The mixed material obtained in the melting and mixing process is subjected to grinding and classification process ST3 to obtain toner of a desired size. Thus, it is possible to obtain a developer which is excellent in fixability such as fixing remaining rate and smear-proofing, offset resistance, quality keeping and fluidity.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an electrophotographic developer, and more particularly to an electrophotographic developer used in a heat fixing method.

[0002]

2. Description of the Related Art Conventionally, a developer has (1) a high fixing residual rate, (2) a good smear characteristic, and (3).
It has been required to simultaneously satisfy various characteristics such as not causing an offset phenomenon. Here, the fixing residual rate indicates the fixing strength of the developer fixed on the recording medium, and the higher the fixing residual rate, the more the fixing is performed. Smear means that when a recorded sheet of paper or the like is used as an original and it passes through an automatic original feeder, the fixed developer image receives mechanical frictional force and peels from the paper,
This is a phenomenon in which a peeled developer image appears as image stains on another sheet. The offset phenomenon refers to a phenomenon in which a developer that is heated and melted at the time of fixing adheres to a fixing device to cause image contamination. Particularly, when the heating and pressure fixing is performed by the pair of fixing rollers, the heat-melted toner adheres to the pressure roller to cause so-called back stain that contaminates the back side of the sheet.

In order to satisfy such various characteristics at the same time, for example, JP-A-4-358159 discloses that two kinds of waxes having different softening point temperatures are contained in the toner. However, it has been difficult to uniformly disperse a plurality of different types of waxes in the binder resin, which is the main component of the developer.

[0004]

As described in detail above,
In conventional electrophotographic developers, in order to simultaneously satisfy a plurality of properties required for the developer, it is desired to contain a plurality of types of wax, but a plurality of types of wax are used as binder resin. There is a problem in that it is difficult to uniformly disperse the particles in the toner, so that a satisfactory developer cannot be produced. An object of the present invention is to solve the above problems and to provide an electrophotographic developer excellent in offset resistance, storability, fluidity and fixability.

[0005]

According to the present invention, firstly, a polymerizable monomer and a first wax having a viscosity of a first magnitude are dispersed in a solution and the solution is stirred to form the polymerizable monomer. A step of producing a resin containing the first wax by polymerizing the wax, and a resin, a colorant, and a second larger than the first size produced in the step of producing the resin containing the wax. And a melt-kneading step of melt-kneading a second wax having a viscosity of 1.

Secondly, the present invention provides a polymerizable monomer and a viscosity ρ _{1 at a} temperature of 100 ° C. of 100 to 1000 cP.
And a wax-added resin production step of producing a resin containing the first wax by stirring the solution in which the first wax is dispersed to perform polymerization with the polymerizable monomer.
The resin produced in the wax-added resin production process, the colorant, and the viscosity at a temperature of 100 ° C. of 10,000 to 1
A melt-kneading step of melt-kneading a second wax of 00000 cP is provided.

The present invention comprises, thirdly, a polymerizable monomer and a first monomer.
A step of producing a resin containing the first wax by stirring a solution in which a first wax having a viscosity of 1 is dispersed to perform polymerization with the polymerizable monomer, The resin manufactured in the wax-added resin manufacturing process, the colorant, and the second larger than the first size.
And a melt-kneading step of melt-kneading a second wax having a viscosity of about 1 to 7 parts by weight with respect to 100 parts by weight of the toner material mixture, The second wax is included in an amount of 0.1 to 3 parts by weight, based on 100 parts by weight of the toner material mixture.

Fourthly, the present invention comprises: stirring a solution in which a polymerizable monomer and a first wax having a number average molecular weight of 1500 to 4000 are dispersed to carry out polymerization with the polymerizable monomer; A step of producing a resin containing the first wax, and a resin produced in the step of producing a resin containing the wax, a colorant, and a number average molecular weight of 8
And a melt-kneading step of melt-kneading the second wax of 000 to 11000.

The fifth aspect of the present invention is the polymerizable monomer and the first aspect.
A wax internal addition resin containing the first wax obtained by stirring a solution in which a first wax having a viscosity of the above is dispersed and performing polymerization with the polymerizable monomer, and a colorant And a second wax having a viscosity of a second magnitude larger than the first magnitude, which is obtained by melt-kneading.

Sixth, the present invention provides a polymerizable monomer and a viscosity ρ _{1 at a} temperature of 100 ° C. of 100 to 1000 cP.
The wax-containing resin containing the first wax obtained by stirring the solution in which the first wax is dispersed and performing the polymerization with the polymerizable monomer, a colorant, and a temperature of 100 ° C. Viscosity at 10,000 to 10
A developer obtained by melt-kneading a second wax of 0000 cP.

Seventh, the present invention relates to a polymerizable monomer and a first.
A wax internal addition resin containing the first wax obtained by stirring a solution in which a first wax having a viscosity of the above is dispersed and performing polymerization with the polymerizable monomer, and a colorant And a first wax obtained by polymerizing the polymerizable monomer and the first wax having a viscosity of the first magnitude dispersed in the solution by stirring the solution. A wax internally added resin,
In a developer obtained by melt-kneading a colorant and a second wax having a second size viscosity larger than the first size, the first wax is added to 100 parts by weight of the toner material mixture. On the other hand, 1 to 7 parts by weight, and the second wax is 100 parts by weight of the toner material mixture,
Provided is a developer characterized by being contained in an amount of 0.1 to 3 parts by weight.

The eighth aspect of the present invention is to stir a solution in which a polymerizable monomer and a first wax having a number average molecular weight of 1500 to 4000 are dispersed to carry out polymerization with the polymerizable monomer. The obtained wax-containing resin containing the first wax, a colorant, and a number average molecular weight of 80
There is provided a developer characterized by being melt-kneaded with a second wax of 00-11000.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION According to the method for producing a developer of the first invention, the solution in which the polymerizable monomer and the first wax having the viscosity of the first magnitude are dispersed is stirred to A wax-added resin production step of producing a resin containing the first wax by polymerizing with a polymerizable monomer;
A resin manufactured in the wax-added resin manufacturing process, a colorant, a charge control agent, etc., and a second larger than the first size.
A method for producing a developer is provided, which comprises a melt-kneading step of melt-kneading a second wax having a viscosity of the following formula, and a step of crushing the melt-kneaded toner material mixture to form toner particles. .

According to the present invention, the first wax having a low viscosity is added, that is, internally added during polymerization production of the binder resin, and the second wax having a higher viscosity than the first wax is melt-kneaded in the toner material mixture. Addition, that is, external addition, can improve the wax dispersibility of the toner, and at the same time, the toner obtained has an offset resistance,
It is possible to obtain a developer for electrophotography, which is excellent in storability, fluidity and fixability.

A low viscosity first wax and a high viscosity second wax.
The wax is added separately at the time of polymerization and at the time of kneading. FIG. 1 is a flow chart showing the outline of the method for producing a developer according to the first invention.

In the method for producing a developer of the present invention, as shown in FIG. 1, first, in a step of producing a resin containing a wax, the first wax is mixed with a polymerizable monomer for constituting a binder resin in a solvent. In the polymerization step S
Polymerization with stirring is performed at T1.

Next, the resin produced in the wax-added resin production step is melt-kneaded together with the second wax having a higher viscosity than the first wax and the colorant in the melt-kneading step ST2 while heating.

The kneaded product obtained in this melt-kneading step is crushed and subjected to a classification step ST3 to obtain a toner of a desired size. Here, the viscosity of the wax will be described. Viscosity is the internal friction of a liquid and can be determined by measuring the time it takes for a given amount of liquid to flow through a capillary tube.
The viscosity of the wax varies depending on the constituent components. The wax having a higher molecular weight has a higher viscosity, and the wax having an ester having a higher degree of unsaturation with the same carbon number has a lower viscosity. The viscosity can be roughly classified into three types: absolute viscosity, kinematic viscosity, and industrial viscosity.

The absolute viscosity is defined physically correctly, and its unit is Poise (P, 1P = 1 g / cm · s).
Expressed as 1/100 of poise, centipoise (cP)
Say. The kinematic viscosity is the absolute viscosity divided by the density of the liquid at the same temperature. The unit is Stokes (St), and 1/100 of Stokes is centistokes (cS
t). The industrial viscosity is a viscosity unit obtained by using a specific instrument such as a Redwood viscometer, a Saybolt viscometer, and the like based on a uniquely specified measurement method. The method of measuring the viscosity of the wax used in this proposal is the Brookfield viscosity measuring method using a Brookfield viscometer.

The Brookfield viscometer is a kind of inner cylinder rotary type rotary viscometer. Without using the outer cylinder, hang the inner cylinder directly into the sample and give it a certain number of rotations,
The resistance of the inner cylinder due to the viscosity of the sample is measured. This is convenient because it is possible to directly measure the viscosity of the sample in the liquid saw during operation in a factory or the like. Also called a B-type viscometer.

The second invention is one of the preferred embodiments of the first invention, wherein the polymerizable monomer and the viscosity ρ _{1 at a} temperature of 100 ° C. are 100 to 1000 cP.
The wax-added resin manufacturing step of manufacturing a resin containing the first wax by stirring the solution in which the wax is dispersed and polymerizing with the polymerizable monomer, and the wax-added resin manufacturing step Resin, colorant and viscosity at 100 ° C of 10,000 to 100,000
Provided is a method for producing a developer, which comprises a melt-kneading step of melt-kneading a second wax of cP and a step of crushing a melt-kneaded toner material mixture to form toner particles.

When the viscosity of the first wax at a temperature of 100 ° C. is less than 100 cP, the wax has no compatibility with the resin and tends to not be in a good dispersed state in the toner, which exceeds 1000 cP. When,
The wax has a too high viscosity, and even if it is added during the polymerization of the binder resin, it tends not to be in a good dispersed state.

When the viscosity of the second wax at a temperature of 100 ° C. is less than 10000 cP, the second wax has a large difference in viscosity with the resin, so that the second wax has no compatibility and tends to be in a good dispersed state in melt kneading. If it exceeds 100,000 cP, the fluidity of the wax itself deteriorates, and there is a tendency that a good dispersed state is not obtained.

Further, the third invention is one of the preferred embodiments of the first invention, in which the solution in which the polymerizable monomer and the first wax having the viscosity of the first size are dispersed is stirred. Polymerizing with a polymerizable monomer to produce a resin containing the first wax, and a resin, a colorant and a first size produced by the wax-containing resin producing step. A melt-kneading step of melt-kneading a second wax having a second magnitude of viscosity greater than
In a method for producing a developer, which comprises a step of pulverizing a melt-kneaded toner material mixture to form toner particles,
The first wax may be included in an amount of 1 to 7 parts by weight based on 100 parts by weight of the toner material mixture, and the second wax may be included in an amount of 0.1 to 3 parts by weight based on 100 parts by weight of the toner material mixture. Provided is a method for producing a developer.

Further, the addition amount of the first wax is 1% by weight.
If the amount is less than the above, the amount of the release agent tends to be too small, and the offset resistance tends to be deteriorated. If the amount exceeds 7% by weight, the wax is once dispersed in the toner, but the two are melted again to be in a good dispersion state. do not become. If the amount of the second wax added is less than 0.1% by weight, smear resistance tends to deteriorate, and if it exceeds 3 parts by weight, a good dispersed state tends not to be obtained.

The fourth invention is one of the preferred embodiments of the first invention, in which the solution in which the polymerizable monomer and the first wax having a number average molecular weight of 1500 to 4000 are dispersed is stirred. By a polymerizable monomer to produce a resin containing a first wax, and a resin, a colorant, and a number average molecular weight of 8000, which are produced in the wax-added resin production step. A method for producing a developer is provided, which comprises a melt-kneading step of melt-kneading a second wax of 11000 to 11000 and a step of crushing the melt-kneaded toner material mixture to form toner particles.

The number average molecular weight of the first wax is 1500.
If it is less than 1, high temperature offset tends to occur,
When the number average molecular weight of the first wax exceeds 4000,
When the number average molecular weight of the second wax is less than 8,000, smear resistance tends to be deteriorated, and when the number average molecular weight of the second wax is more than 11,000, good offset occurs. It is not in a dispersed state and tends to cause problems such as filming.

In the above second to fourth inventions, it is possible to use a combination of the characteristics of the first and second waxes used. In the method for producing a developer of the present invention, the total amount of the first wax and the second wax added is preferably 10% by weight or less.

In the method for producing a developer of the present invention, the addition weight ratio of the first wax and the second wax is
It is preferably 1: 3 to 70: 1. As the binder resin material, for example, a binder resin monomer, a solvent, a polymerization initiator, a molecular weight modifier, etc. can be used.

As the resin used as the binder of the developer, polystyrene, styrene-butadiene copolymer,
Styrene-based copolymers such as styrene-acrylic copolymers,
Polyethylene, ethylene-vinyl acetate copolymer, ethylene-based copolymer such as ethylene-vinyl alcohol copolymer, phenolic resin, polyamide resin, polyester resin, maleic acid resin, polymethylmethacrylate,
So-called petroleum resins such as polyacrylic acid, polyvinyl butyral, aliphatic hydrocarbon resins, alicyclic hydrocarbon resins and aromatic hydrocarbons, chlorinated paraffins and the like and mixtures thereof can be used.

As the colorant used in the developer, for example, carbon black, fast yellow G, benzidine yellow, pigment yellow, indo first,
Orange, Irgadine Red, Carmine FB, Permanent Bordeaux FRR, Pigment Orange R, Resole Red 2G, Lake Red C, Rhodamine FB, Rhodamine B Lake, Phthalocyanine Blue, Pigment Blue, Brilliant Green B, Phthalocyanine Green, Quinacridone, etc. Known colorants can be used.

Further, to the developer, an antistatic agent such as a metal dye, a ligrosin type or a polyamine type can be added for the purpose of controlling the amount of charge given by the carrier particles. These charge control agents can be used as a mixture with the nuclear toner and / or the surface treatment agent.

Further, in order to improve the fluidity and anti-aggregation resistance of the colored particles, hydrophobic colloidal particles having the same polarity as the colored particles, such as colloidal silica, may be added if necessary. .

In addition to colloidal silica, aluminum oxide, titanium oxide, silicon oxide, zinc oxide, magnesium oxide, calcium oxide, tin oxide, silicon may be used in addition to colloidal silica in order to improve the fluidity of the colored particles and stabilize the charge amount. Inorganic oxides such as indium oxide, cerium oxide and molybdenum trioxide, coupling agents such as silane coupling agents and titanium coupling agents on the surface, inorganic oxides surface-treated with silicone oil, polystyrene, styrene-butadiene Copolymers, styrene-based copolymers such as styrene-acrylic copolymers, polyethylene and ethylene-based copolymers, aliphatic copolymers such as polymethylmethacrylate, alicyclic copolymers, silicone resins, Teflon, etc. Resin fine powder, resin fine powder whose surface is treated with a coupling agent, silicone oil, etc. , Magnetite, may be added to the magnetic powder such as ferrite. Incidentally, the charging polarity of the developer in the invention may be positive or negative.

The fifth to eighth inventions respectively relate to a developer obtained by the method according to the first to fourth inventions. FIG. 2 is a schematic view of an image forming apparatus that can use the developer according to the present invention.

In FIG. 2, the photosensitive drum 3 as an image bearing member is rotatably provided in the direction of arrow a in the figure. The following components are arranged around the photosensitive drum 3 along the rotation direction. In FIG. 2, the photosensitive drum 3
The charging charger 5 that uniformly charges the photosensitive drum 3 is
Are provided opposite to each other.

Above the photoconductor drum 3, a document table glass 7 on which a document is placed, an automatic document feeder (hereinafter referred to as an ADF 8) for feeding a document on the document table glass 7, and a charged photoconductor drum. 3 is provided with an exposure unit 9 which forms an electrostatic latent image by performing exposure according to the original image. A
The detailed configuration of the DF8 will be described later.

The exposure unit 9 includes an exposure lamp 11 which serves as a light source,
Reflection mirrors 13a, 13b, 13c, 13d, 13 that guide the light emitted from the exposure lamp 11 onto the photosensitive drum 3.
e, 13f, a slit glass 13g, and a lens unit 14 for forming an image of reflected light.

A developing device 1 for accommodating a toner T as a developer and a carrier (not shown) downstream of the exposure unit 9 and developing the electrostatic latent image formed by the exposure unit 9 with the toner T.
5 are provided. Downstream of the developing device 15, a transfer charger 17 for transferring the toner image formed by the developing device 15 on a sheet P as an image forming medium is provided.

Charging charger 5, exposure unit 9, developing unit 15
Constitutes a developer image forming means. Adjacent to the transfer charger 17, a peeling charger 19 for peeling the paper P electrostatically attached to the photosensitive drum 3 at the time of transfer is arranged. A cleaning device 21 for removing the toner T remaining on the photosensitive drum 3 after the transfer is provided downstream of the peeling charger 19. The cleaning device 19 has a cleaning blade 23. A charge eliminator 25 that removes charges on the photoconductor drum 3 is provided downstream of the cleaning device 19.

In FIG. 2, on the right side of the photosensitive drum 3, a paper feed cassette 27 for accommodating the paper P is detachably provided in the main body of the image forming apparatus 1. Further, a pickup roller 29 for taking out the paper P in the paper feed cassette 27 is attached to the main body of the image forming apparatus 1. Further, a paper feed roller pair 31 is provided near the pickup roller 29 to separate and feed the paper P one by one.

An aligning roller pair 32 is provided upstream of the transfer charger 17 along the transport direction of the paper P to feed the transported paper P toward the photosensitive drum 3 at a predetermined timing. The aligning roller pair 32 nips and conveys the paper P, and supplies the paper P between the photoconductor drum 3 and the transfer charger 17.

Downstream of the transfer charger 17 along the conveyance direction of the paper P, the peeling charger 19 and the paper P described above are provided.
Belt 3 that carries the toner and transports it to a fixing device 35 described later
3 and a fixing device 35 as fixing means for fixing the toner image on the sheet P are provided.

The conveyor belt 33 is made of an insulating material, and is charged by the transfer charger 17 to electrostatically adsorb the charged paper P and conveys it to a fixing device 35 described later.

The fixing device 35 has a pair of rollers composed of a heating roller 37 and a pressure roller 39. The toner image is fused and fixed on the paper P by rotating the heating roller 37 and the pressure roller 39 in the directions indicated by arrows c and d, respectively.

A paper discharge roller pair 43 for discharging the fixed paper P to the outside of the image forming apparatus 1 and a paper discharge tray for receiving the discharged paper P are provided downstream of the fixing device 35 along the conveyance direction of the paper P. 45 are provided.

On the other hand, the ADF 8 has an original placing table 47 on which an original is placed and a pickup roller 49 for taking out the original placed on the original placing stand 47. The original is placed on the original placing table 47 with the original side up. In the vicinity of the pickup roller 49, a separation belt 51 and a sheet feeding roller 53 for separating and feeding the documents one by one toward the platen glass 7 are provided to face each other. An aligning roller 55 is provided between the separation belt 51 and the sheet feeding roller 53 and the platen glass 7 to align the original and send it out onto the platen glass 7.

An original conveying belt 57 for conveying an original on the original table glass 7 is provided opposite to the original table glass 7. Document conveying belt 57 along the document conveying direction
A reversing roller 59 for reversing the document and a discharge roller 61 for discharging the document to the outside of the ADF 8 are provided downstream of the document.

An image forming process in the image forming apparatus 1 thus constructed will be described. When the image formation start is instructed via an operation panel or the like (not shown), the photosensitive drum 3 starts rotating in the direction of arrow a in the figure. The charging charger 5 uniformly charges the surface of the rotating photosensitive drum 3.

The ADF 8 sends out the originals one by one onto the original table glass 7. The exposure lamp 11 irradiates the original placed on the original table glass 7 with light to move the original, and the exposure unit 9 exposes the charged photosensitive drum 3 in accordance with the original image to form an electrostatic latent image. To form.

The developing device 15 attaches the charged toner T to the electrostatic latent image to form a toner image. The paper P is fed from the paper feed cassette 27 to the pickup roller 29 and the paper feed roller pair 3.
1 is taken out one by one by rotation of 1, and the photoconductor drum 3 and the transfer charger 1 are moved by the aligning roller pair 32.
It is supplied between 7 and.

The transfer charger 17 applies a charge having a polarity opposite to the charging polarity of the toner T to the back surface of the supplied paper P, and transfers the toner image onto the paper P. Peeling charger 19 is A
By performing C corona discharge, the paper P adhered to the photosensitive drum 3 at the time of transfer is separated from the photosensitive drum 3. The transported belt 33 transports the peeled sheet P toward the fixing device 35.

The fixing device 35 heats and melts the heated toner image on the paper P to fix the toner image on the paper P. After that, the paper P is discharged from the discharge tray 4 by rotation of the discharge roller pair 43.
5 is discharged.

On the other hand, the photosensitive drum 3 is a cleaning device 2
After the toner T remaining after the transfer is removed by 1, the charge is removed by the charge remover 25. The charge removal by the charge remover 25 completes one cycle of the image forming process, and the photosensitive drum 3 is charged again by the charger 5 at the time of the next image formation. On the other hand, the original is transported by the original transport belt 57 and discharged out of the ADF 8.

[0055]

EXAMPLE An image was formed with a developer having the following composition by using the image forming apparatus having the above-mentioned structure. Example 1-9 The binder resin added with the low-viscosity first wax was
For example, it can be manufactured using the following method.

First, a reaction vessel was charged with a predetermined amount of xylene and polypropylene wax, styrene, n-butyl acrylate, and di-t-butyl peroxide were added thereto, and the inside of the vessel was replaced with nitrogen gas. It was heated to the boiling point of xylene (135 ° C to 145 ° C). While stirring under reflux of xylene, a mixed solution of styrene, n-butyl acrylate and benzoyl peroxide (polymerization initiator) was added dropwise over 2 hours to carry out solution polymerization. After completion of the dropping, aging was carried out for 1 hour while stirring under reflux of xylene. Then, the temperature in the container was gradually raised to 180 ° C., and xylene was removed under reduced pressure to obtain a binder resin containing a low-viscosity polypropylene wax.

Using the styrene-acrylic copolymer resin containing the polypropylene low-viscosity wax obtained as described above, a toner was manufactured, for example, as follows. To 100 parts by weight of styrene-acrylic copolymer resin containing a polypropylene low viscosity wax at the time of polymerization,
5 parts by weight of carbon black, metal complex salt of monoazo dye 2
A toner material mixture was obtained by mixing 1 part by weight, 0.1 part by weight of hydrophobic silica and a high viscosity polyethylene wax. Here, the viscosity and the content of the polyethylene-based high-viscosity wax and the viscosity and the content of the polypropylene-based low-viscosity wax were variously changed as shown in Tables 1 and 2 to obtain the viscosity of Example 1-9 and Comparative Example 1-3. A toner material mixture was obtained.

[0058]

[Table 1]

[0059]

[Table 2]

In Table 1, A indicates a low-viscosity first polypropylene wax, and B indicates a high-viscosity second polyethylene wax. Further, ρ ₁ and ρ ₂ are viscosities at 100 ° C., and the unit thereof is cP.

After the above materials are mixed, they are kneaded with a kneader (pressure kneader) at about 170 ° C. for 30 minutes and then pulverized.
Further, it was finely pulverized with an I-type jet mill-DS classifier, and a toner having a 50% volume average particle diameter of 11.0 μm was obtained by air classification.

The following tests were conducted on the obtained toner. Table 1 shows the results. 1) Fixing residual rate test At low temperature and low humidity (10 ° C, 20%), halftone images (ID 0.6 to 0.8) are fixed at a fixing temperature of 200 ° C,
The image was subjected to a rubbing test using a rubbing fastness tester to measure image densities before and after the test to evaluate the residual fixing rate.

For the test, Toshiba Leo Dry 6550 was used.
When the residual rate before and after rubbing is 75% or more,
0 to 74% was designated as Δ, and 69% or less was designated as x. 2) Smear test Toshiba TOSHIBA TEST CHART-61
Using an image forming apparatus, 50 sheets were printed in a hammer mill letter size, and then passed through ADF. After passing the paper, the image stain caused by the pressure of the separation belt roller, friction, etc. was evaluated.

For the test, Toshiba Leo Dry 6550 was used.
The ADF was also used for the aircraft. The fixing temperature was 200 ° C. Smear level 0 depending on the degree
In the evaluation of this test, the level 5 or less was evaluated as ◯, 6 to 7 was evaluated as Δ, and 8 or more was evaluated as x.

3) Offset resistance test The offset test chart was measured using an image forming apparatus.
Images were continuously printed on 10 sheets in a hammer mill letter size.
At this time, all the cleaning members of the fixing device were removed, and the oil of the heat roller and the press roller was wiped off cleanly before the test.

In the test, Toshiba's Leo Dry 6550 was used.
It was used. The offset resistance is ranked from level 0 to level 5 according to its degree, and in the evaluation of this test, level 2 or lower was evaluated as ◯, 3 was evaluated as Δ, and 4 or more was evaluated as x.

4) Preservation test 20 g of the toner was put in 100 ml of polybin and allowed to stand in a water bath at 55 ° C. for 8 hours, and then the fluidity was evaluated by a powder tester (manufactured by Hosokawa Micron Corporation). (2
Vibrate with a 00 mesh sieve for 10 seconds) In addition, 5 g or less of what remains on the mesh is ○, 5.1
g to 10 g were evaluated as Δ, and 10.1 g or more was evaluated as x.

As is clear from Table 1, in Examples 1 to 9, the dispersibility, the residual fixing rate, the smearing property, the offset resistance and the storage stability were all good. However, as is clear from Comparative Example 1 in Table 2, in the case of the toner containing only the low-viscosity polypropylene wax, the smear property is poor even if the wax is added during the polymerization of the binder resin. On the other hand, as is clear from Comparative Example 2, when only the high-viscosity polyethylene wax was contained, the offset resistance was poor even when the wax was added during melt kneading. Further, in Comparative Example 3 in which the low-viscosity polypropylene wax was added during melt-kneading and the high-viscosity polyethylene wax was added during binder resin polymerization, dispersibility and storability were particularly poor.

Example 10-17 5 parts by weight of carbon black and a metal of a monoazo dye were added to 100 parts by weight of a styrene-acrylic copolymer resin containing 3 parts by weight of a polypropylene low viscosity wax having a viscosity of 100 cP at 100 ° C. at the time of polymerization. 2 parts by weight of complex salt, 0.1 part by weight of hydrophobic silica, viscosity 1000 at 100 ° C.
A toner material mixture was obtained by mixing 1 part by weight of a 0 cP polyethylene-based high-viscosity wax. Here, the number average molecular weight of the polyethylene-based high-viscosity wax and the number average molecular weight of the polypropylene-based low-viscosity wax were variously changed as shown in Table 3 to obtain toner material mixtures of Examples 10-17. Using the obtained toner material mixture, a toner was manufactured in the same manner as in Example 1-9, and the obtained toner was subjected to each test and evaluation. Table 3 shows the results.

[0070]

[Table 3]

In Table 3, Mn ₁ represents the number average molecular weight of the polyethylene high viscosity wax, and Mn ₂ represents the number average molecular weight of the polypropylene low viscosity wax. As is clear from Table 3, the number average molecular weights of the low-viscosity polypropylene wax added at the time of polymerization of the binder resin and the high-viscosity polyethylene wax added at the time of melt-kneading as in Examples 10 to 13 are in the preferred range of the present invention, that is, 1500.
In the case of ˜4000 cP and 8000 to 11000 cP, the dispersibility, the residual fixing rate, the smearing property, the offset resistance, and the storability were all good, but Example 14-1
7, when the number average molecular weight of one or both of the low-viscosity polypropylene wax added during polymerization of the binder resin and the high-viscosity polyethylene wax added during melt-kneading is outside the preferred range of the present invention, , Fixing residual rate, smearing property, offset resistance,
And, at least one of the storage properties is slightly inferior to Examples 10-13.

Backside Staining and Member Staining Test Further, in Example 1-17 and Comparative Example 1-3, the toner remaining on the heat roller due to the occurrence of offset is transferred to the press roller and the backside of the paper is soiled, and the fixing is performed. The cleaning member of the container was inspected for dirt.

In the test, Toshiba's Leo Dry 6550 was used.
Was used, and both the back stain and the stain on the member were rated as level 3 or less. As a result, all of Examples 1 to 17 in the invention were good. Further, Comparative Example 1 was good, but Comparative Examples 2 and 3 were poor.

In the present invention, the low viscosity wax is 10
At 0 ° C, its viscosity is 100 to 1000 cP,
High-viscosity wax has a viscosity of 100 at 100 ° C.
Although a wax having a viscosity of 00 to 100,000 cP was used, it is more preferable that the low viscosity wax and the high viscosity wax satisfy the following relational expressions.

When the viscosity ρ ₁ of the low-viscosity wax is ρ ₁ = α ₁ × T ₁ + C ₁ −9.78 ≦ α ₁ <0 and T ₁ = 100 ° C. 10
0 ≦ ρ ₁ ≦ 1000 When viscosity ρ ₂ of high-viscosity wax is ρ ₂ = α ₂ × T ₂ + C ₂ −950 ≦ α ₂ <0 and T ₂ = 100 ° C. 100
00 ≦ ρ ₂ ≦ 100000 The viscosity of wax changes with temperature. When various waxes are used as the low-viscosity wax and the high-viscosity wax, respectively, if the wax satisfies the above relationship, the toner is used. It was found that each wax exhibits an appropriate viscosity under the above temperature environment, and the toner containing both waxes has excellent smear characteristics and a fixing residual rate.

FIG. 3 shows the results of investigating the relationship between the viscosity and the temperature of some waxes suitable as the first wax in the present invention. Further, FIG. 4 shows the results of examining the relationship between the viscosity and the temperature of some waxes suitable as the second wax in the present invention. Table 4 shows the data of the points plotted in FIGS. 3 and 4.

[0077]

[Table 4]

[0078]

As described above, according to the present invention, the first wax material having a low viscosity is added during the polymerization of the binder resin, and the second wax having a viscosity higher than that of the first wax is added during the melt-kneading of the resin mixture. By adding the above wax, an electrophotographic developer having excellent fixability such as residual fixing rate and smearing property, offset resistance, storability, and fluidity can be obtained.

[Brief description of drawings]

FIG. 1 is a flowchart showing an outline of a method for producing a developer according to a first invention.

FIG. 2 is a schematic diagram for explaining an image forming apparatus that can use the developer according to the present invention.

FIG. 3 is a graph showing the relationship between the viscosity of the first wax and the temperature.

FIG. 4 is a graph showing the relationship between the viscosity of the second wax and the temperature.

[Explanation of symbols]

 1 ... Image forming device 3 ... Photosensitive drum 5 ... Charging charger 8 ... ADF 9 ... Exposure part 11 ... Exposure lamp 15 ... Developing device 17, 19 ... Transfer charger 21 ... Cleaning device 23 ... Cleaning blade 27 ... Paper feeding cassette 29 ... Pickup Roller 35 ... Fixing device 37 ... Heating roller 39 ... Pressure roller

Front page continuation (72) Inventor Kunobu Ajima 70, Yanagimachi, Saiwai-ku, Kawasaki-shi, Kanagawa Toshiba Intelligent Agents Co., Ltd.

Claims (8)

[Claims] 1. A solution in which a polymerizable monomer and a first wax having a viscosity of a first magnitude are dispersed is stirred to carry out polymerization with the polymerizable monomer, thereby containing the first wax. And a colorant and a second wax having a viscosity of a second size larger than the first size, which is manufactured by the wax-added resin manufacturing process. And a melt-kneading step of melt-kneading. 2. A solution in which a polymerizable monomer and a first wax having a viscosity ρ _{1 at a} temperature of 100 ° C. of 100 to 1000 cP are dispersed is stirred to carry out polymerization with the polymerizable monomer, A step of producing a resin containing a wax, and a resin produced in the step of producing a resin containing a wax, a colorant, and a viscosity at a temperature of 100 ° C. of 10,000 to 1
And a melt-kneading step of melt-kneading a second wax of 00000 cP. 3. A solution in which a polymerizable monomer and a first wax having a viscosity of a first magnitude are dispersed is stirred to polymerize with the polymerizable monomer, and the first wax is contained. And a colorant and a second wax having a viscosity of a second magnitude larger than the first magnitude, which are produced in the wax-added resin production step. In the method for producing a developer, which comprises a melt-kneading step of melt-kneading, the first wax is 1 to 7 with respect to 100 parts by weight of the toner material mixture.
Parts by weight, the second wax is the toner material mixture 10
0.1 to 3 parts by weight relative to 0 parts by weight, a method for producing a developer. 4. The polymerizable monomer and the number average molecular weight are 150.
The solution in which the first wax of 0 to 4000 is dispersed is stirred to polymerize with the polymerizable monomer.
A step of producing a resin containing a wax, and a resin produced in the step of producing a resin containing wax, a colorant, and a number average molecular weight of 8000 to 11000.
And a melt-kneading step of melt-kneading the above wax. 5. The first obtained by stirring a solution in which a polymerizable monomer and a first wax having a viscosity of a first magnitude are dispersed to carry out polymerization with the polymerizable monomer. A developer obtained by melt-kneading a wax-containing resin containing the above wax, a colorant, and a second wax having a viscosity of a second size larger than the first size. . 6. A solution obtained by dispersing a polymerizable monomer and a first wax having a viscosity ρ ₁ of 100 to 1000 cP at a temperature of 100 ° C., and stirring the solution to obtain a polymerizable monomer. And a wax-containing resin containing the first wax, a colorant, and a temperature of 100 ° C.
A developer obtained by melt-kneading a second wax having a viscosity of 10,000 to 100,000 cP. 7. A first solution obtained by polymerizing the polymerizable monomer and the first wax having a viscosity of a first magnitude in a solution with stirring to carry out polymerization with the polymerizable monomer. A wax-containing resin containing the above wax, a colorant, a polymerizable monomer, and a first viscosity having a first magnitude.
The wax-containing resin containing the first wax obtained by stirring the solution in which the wax is dispersed and performing the polymerization with the polymerizable monomer, the colorant, and the size larger than the first size. In a developer obtained by melt-kneading a second wax having a second viscosity, the first wax is 1 to 7 parts by weight based on 100 parts by weight of the toner material mixture. The wax is included in an amount of 0.1 to 3 parts by weight based on 100 parts by weight of the toner material mixture. 8. The polymerizable monomer and the number average molecular weight are 150.
A wax-containing resin containing the first wax, which is obtained by stirring a solution in which the first wax of 0 to 4000 is dispersed and performing polymerization with the polymerizable monomer; and a colorant. Number average molecular weight is 8000 to 11,000
And a second wax that is melt-kneaded.