JPS63113482A - Method and device for image formation - Google Patents

Abstract

PURPOSE:To obtain an image of good quality stably for a long period by using specific polymerization toner, applying a press-contacting force to toner and increasing its heat flowability, and lowering the temperature at the time of transfer and fixation. CONSTITUTION:Toner which forms a toner image is the polymerization toner obtained by adding a 50-3,000wt.pts. low-softening point compound having a 40-130 deg.C softening point to a 100wt.pts. polymer made of polymerizing monomer. Then an image transferred to an intermediate transfer body 20 is transferred to and fixed on a transfer material passing between the intermediate transfer body 20 and a pressurizing body 3 at high temperature under pressure higher than the press-contacting force between a photosensitive body 1 and the intermediate transfer body 20. No electrostatic transfer means is employed for transfer, so the disorder of the image and a decrease in its sharpness caused by the weakness of the sticking force of toner to the transfer material are eliminated, and the temperature rise of the photosensitive body is suppressed to make characteristics hard to change, so the life can be prolonged and the image of good quality is obtained stably for a long period.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an image forming method and image forming apparatus for electrostatically forming an image, such as an electrophotographic apparatus and a printer thereof.

(Prior art) A photoreceptor having a photoconductive layer on its surface is charged uniformly and with a specific polarity, and a light image is projected onto the photoconductive layer using a timely image signal writing means to form an electrostatic latent image. Then, fine particles of toner charged to the opposite polarity to the latent image are electrostatically applied to the latent image to form a toner image, and this toner image is transferred to a sheet-like transfer material mainly made of paper. The toner image is electrostatically transferred to a transfer material by applying a charge of opposite polarity to the toner, and then this transfer material is transferred to a fixing site, and pressure or heat and pressure is applied to transfer the toner image to the transfer material. Image forming methods and image forming apparatuses configured in this manner have been widely used.

In such an image forming apparatus, since the toner image is electrostatically supported on the transfer material, a considerable amount of toner remains on the surface of the photoreceptor even after transfer (transfer rate is about 80 to 90%), resulting in poor image density. I couldn't avoid going low.

Furthermore, since the toner is moved electrostatically, it is difficult to completely prevent the toner from scattering, which may impair the clarity of the image or stain various parts within the apparatus.

In order to avoid such problems, for example, Japanese Patent Laid-Open No. 55-134872 or U.S. Pat.
As seen in the specification of No. 927, a transfer means using pressure has been proposed.

However, this type of device requires two
Since a pressure of about 0.00 kg/crrr is used, it is difficult to directly transfer the toner image on the surface of the photoreceptor to the transfer material, and it is necessary to transfer the electrostatic latent image to a dielectric layer, which is an intermediate transfer member. However, there have been disadvantages such as an increase in the size of the device and a complicated mechanism, and a reduction in image resolution due to the transfer of the electrostatic latent image.

Also, U.S. Patent Nos. 3,591,276 and 366
As seen in the specification of No. 9706, a latent image formed on a photoreceptor is visualized and transferred to an intermediate transfer member having a silicone rubber layer, and then this transferred image is transferred to a transfer material by applying heat. Something like transcription has been proposed.

However, for such products, it is necessary to apply heat to bring the temperature near or above the toner's melting point, and the toners conventionally used cannot be pulverized to an appropriate particle size in order to maintain image quality. Moreover, in order to prevent the occurrence of coagulation called blocking, the main resin of the toner had to have a high melting point. For this reason, a large amount of heat is required during transfer and fixing, and this heat increases the temperature of the photoreceptor via the intermediate transfer member, resulting in a problem in that the characteristics of the photoreceptor are impaired.

(Objective of the Invention) The present invention has been made in order to cope with the above-mentioned situation, and is an image forming method that has high transfer efficiency and low heat consumption, and can stably obtain high-quality images over a long period of time. It is an object of the present invention to provide a method and apparatus.

(Technical means for solving the problem and their effects) In order to achieve the above object, in the present invention, an electrostatic latent image is formed on the photoconductive layer of a photoreceptor having a photoconductive layer on a conductive substrate. is made into a developed image with powder toner, this developed image is transferred to an intermediate transfer member that is in pressure contact with the photoreceptor, and the transfer material that passes between the intermediate transfer member and the pressure member that is in pressure contact with the photoreceptor is transferred to the photoreceptor. The intermediate transfer material is heated at a temperature higher than the temperature of the contact surface between the photoreceptor and the intermediate transfer member, and the pressure member is pressed against the intermediate transfer member with a pressure greater than the pressure contact force between the intermediate transfer member and the intermediate transfer member. The toner image is transferred and fixed onto the transfer material, and the toner has a softening point of 40 to 100 parts by weight based on 100 parts by weight of a polymer formed from a polymerizable monomer.
It is a polymerized toner containing 50 to 3000 parts by weight of a compound with a low softening point of 130°C, and by applying the pressure to the toner, the thermal fluidity is increased, and the temperature during transfer and fixing described above is further lowered. It is characterized by this.

FIG. 1 is a schematic side view of an image forming apparatus showing an embodiment of the present invention, in which a photoreceptor 1 having a photoconductive layer on its surface is rotated in the direction of arrow A by a driving source (not shown). Reference numeral 2 denotes an intermediate transfer body constructed on a rotating cylinder made of a rigid material such as urethane rubber, fluorine rubber, or silicone rubber on its surface, and its bearing is supported by a spring (not shown) placed at the end. The photoreceptor is pressed against the photoreceptor by an appropriate means and rotates as a result.

A rotary cylindrical pressurizing body 3 made of a rigid material whose surface is coated with a resin of an appropriate thickness is in pressure contact with the intermediate transfer body 2, and the pressing force between these two is the same as that between the photoreceptor and the intermediate transfer body 2. It is larger than that between the transfer body, and there is also a heater 1 inside this pressure body to heat it.
2 is placed.

As the photoconductive layer formed on the surface of the photoreceptor 1, it is preferable to use amorphous silicon or an organic semiconductor having relatively high voltage resistance, and furthermore, a material having a surface energy of 35 dynes/cm or less, such as silicon, is preferably used. It is preferable to form the photoreceptor by directly applying or mixing a resin, a fluororesin, or a block polymer having a functional organ thereof. The thickness of the surface layer formed at this time is 2
μm or less, preferably 1 μm, surface roughness 0.5 μm
RMS or more, preferably about 0.2 μm RMS. The core metal of the photoreceptor is made of a conductive material such as aluminum, aluminum alloy, copper alloy, etc., and its thickness is made so that it can sufficiently withstand the contact pressure with the intermediate transfer member.

The intermediate transfer body 2 has a core metal made of a rigid material such as copper, whose surface is coated with a resin such as silicone rubber, fluorocarbon rubber, or urethane rubber. The window shall be appropriately set within the range of 1 to 5 μm.

Further, as the heat source installed inside the pressurizing body, an appropriate one such as a halogen lamp or a sheet heating element can be used.
A control means (not shown) maintains the surface temperature of the pressurizing body as much as possible at a temperature necessary for transferring and fixing the toner used.

As is well known, on the periphery of the photoreceptor 1 there is a primary charger 5 for uniformly charging the photoconductive layer, and a primary charger 5 for imparting image information to the charged surface to form an electrostatic latent image. an exposure unit 6, a developer 7 that supplies toner to visualize the latent image, a cleaner 4 that removes residual toner remaining on the surface of the photoreceptor after transfer, and an erase lamp 4b that removes residual charges.
, a static eliminator charger 4a, etc. are provided.

Image forming means having such a configuration is well known and will not be described in detail, but as the photoreceptor l rotates, the toner image formed at the position of the developing device 7 is brought into pressure contact with the intermediate transfer member 2 at the nip. It reaches N1.

At this position, the toner image on the photoreceptor is pressure-transferred onto the intermediate transfer member.

As the transfer body rotates, the toner image transferred to the intermediate transfer body in this way is brought into contact with the pressure body 3 at the pressure nip N.
2.

On the other hand, the transfer paper taken out from the reservoir 9 such as a cassette and sent to the conveyance path 13 temporarily waits at the position of the registration roller 10, and then reaches the nip portion N2 in synchronization with the toner image traveling on the intermediate transfer body. After coming into contact with the toner image and receiving the toner image under the action of pressure and heat, it is discharged from the apparatus via a discharge roller.

In the figure, reference numeral 8 is a cleaner for removing residual toner.

Next, talking about the pressure at the nip portions N, N2, the pressure at N1 is 0.1Kg/cd.
If it is less than 60%, the transfer rate will be less than 60%, which is not practical.

Also, 100Kg/err? The above is not preferable because it increases the change in characteristics and wear of the photoreceptor, resulting in a lack of durability. , preferably IKg/crrr or more and 30Kg/cg or less. The higher the pressure at the nip N2, the better the transfer rate, but if it is extremely high, for example, 300 kg
/ crd or more is not preferable because the transfer paper becomes transparent or becomes glossy, making it difficult to see. On the other hand, this pressure is 1
0Kg/crr? Below this, the transfer rate will be less than 60%, which is not practical. Furthermore, if the transfer pressure at the nip portion N is higher than that at the nip portion N2, this is not preferable because the transfer rate at the nip portion N2 will decrease.Practically speaking, the transfer pressure at the nip portion N1 is higher than that at the nip portion N2. Also 30Kg/
It is preferable that it is lower than crrr.

Furthermore, showing the temperature range at nip parts N1 and N2, in nip part N1, when the intermediate comes into contact with the photoreceptor at a high temperature, the dark resistance of the semiconductor photoreceptor tends to decrease, and the charged potential tends to decrease. show. For this reason, the temperature at the nip portion N1 is preferably kept at 30°C to 50°C, preferably 40°C to 50°C.
The temperature is 5°C. For this reason, it is preferable to take cooling means such as a fan (not shown) after the intermediate passes through the nip portion N2. Furthermore, if the temperature at the nip portion N2 is raised to the softening point temperature of the internal wax of the toner used, and if sufficient pressure is applied, sufficient transfer and fixation is possible. These conditions depend on the contact width (width of contact between the intermediate transfer member and the pressure/heating roller during transfer and fixing), temperature, and the moving speed (process speed) of the intermediate transfer member. In other words, if the softening point temperature of the internal wax is 69°C, the temperature at the nip must be 69°C or higher, and the process speed must be at most 69°C.
00mm/see and the nip width is 3 to 4mm, a maximum of 1600C is sufficient, preferably 170℃
It is.

FIG. 2 schematically shows another embodiment of the image forming apparatus according to the present invention, in which the intermediate transfer member is formed in the shape of an endless belt, and a roller 2a in contact with the photoreceptor 1 is shown in FIG. and is wound around a roller 2b that comes into contact with the pressurizing body 3.

It will be readily understood that such a device has the same effect as that of the previous embodiment.

Next, toners that can be used in the present invention will be described in detail.

The toner used in the present invention is a polymerized toner produced in an aqueous medium using a polymerization initiator by a suspension polymerization method from a monomer composition having a small amount (both a polymerizable monomer and a colorant). , polymer 1 formed from polymerizable monomers
The polymerized toner is characterized in that it contains 50 to 3000 parts by weight of a low softening point compound having a softening point of 40 to 130° C. per 00 parts by weight.

The polymerized toner according to the present invention is used for development, and usually has a volume average particle size of about 0.1 to about 30 μm, and contains 100 parts by weight of a polymer produced from polymerizable monomers by suspension polymerization. On the other hand, a low softening point compound with a softening point of 40 to 130℃ is
Contains 3,000 weight and 100% weight. As mentioned above, polymerized toners have excellent blocking resistance even though they contain a large amount of low softening point compounds compared to conventional polymerized toners. This is because the low softening point compound is well encapsulated in the polymer obtained from the polymerizable monomer, and the low softening point compound is not exposed on the surface of the polymerized toner particles.

In the present invention, it is confirmed whether or not the low softening point compound is substantially encapsulated in the polymer by melt-kneading the obtained polymerized toner, cooling it to solidify it, and then pulverizing it, classifying it, and polymerizing it. This is done by preparing a pulverized powder having an average particle size comparable to that of the toner, and comparing the blocking resistance of the prepared pulverized powder with that of the polymerized toner used as a raw material. Blocking resistance is 1 with a diameter of approximately 5 cm.
Agglomerates with a long particle size of about 1 mm or more remaining on a 20-mesh sieve (tiller mesh) after 1 to 5 g of a sample was placed in a 00ml container and left in an environment with a temperature of 50°C and a relative temperature of about 60 ± 5%. It can be measured by the presence or absence of an object.

In the present invention, a plurality of low softening point compounds may be used in combination. The softening points (40 to 130°C) and usage amounts of the multiple low softening point compounds used (TI, W
l), (T 2 , W 2 ) ・・−・−・(T
n-1.

W n -1), (T n , W n ), it is preferable that the following conditions are satisfied.

The amount of the low softening point compound used is based on the assumption that the added polymerizable monomer is almost 100% polymerized to form a polymer, and is 50≦per 100 parts by weight of the polymer. W
1 + W 2 + −・= W n −1+ W n
The condition of ≦3000 is satisfied. In other words, 100 parts by weight of the polymer means 100 parts by weight of the polymerizable monomer that is effectively used to produce the polymer forming the polymerized toner. Therefore, 100 parts by weight of the polymer may be produced by using 100 parts by weight or more of the polymerizable monomer, taking into account the amount dissolved in the aqueous medium and the unreacted amount. If the value deviates from the above conditions and the value is 0.05 or less, the amount of the low softening point compound used is too large, resulting in a decrease in blocking resistance and an increased tendency for the polymerized toner to lack mechanical strength. On the other hand, if the value is 0°8 or more, the degree of improvement in low-temperature fixability and/or low-pressure fixability will be reduced.

The polymerized toner according to the present invention can be produced by the following manufacturing method. That is, a small amount (both polymerizable monomer,
A monomer composition containing a low softening point compound having a low softening point of 40 to 130°C and a colorant was dispersed and granulated in an aqueous medium heated to a high temperature, and the granulation process was substantially completed. Thereafter, a polymerization initiator is added to an aqueous medium containing granulated monomer composition particles and adjusted to a polymerization temperature, and suspension polymerization is carried out. In this case, it is preferable that the temperature of the aqueous medium during the granulation step be higher than the softening point of the low softening point compound in terms of ease of granulation and sharp particle size distribution.

In the above production method, a polymerization initiator for polymerizing the polymerizable monomer is added to the aqueous medium after granulating the monomer composition. Therefore, it is possible to perform granulation by setting the temperature of the aqueous medium, which is the dispersion medium of the monomer composition, to a higher temperature than conventionally. Furthermore, a classification step is provided after granulation to classify the monomer composition particles having a predetermined particle size and the monomer composition particles having an unspecified particle size, and then a polymerization initiator is added to perform polymerization. On the other hand, it is also possible to mix the separated monomer composition particles with an unspecified particle size with other monomer compositions before the polymerization process, re-disperse and granulate them, and reuse them. It is. In addition, during the granulation process, it is possible to raise the temperature of the aqueous medium to a high temperature without considering the decomposition temperature of the polymerization initiator. Even low softening point compounds that are insoluble in polymerizable monomers can be added in large amounts and granulated, and even when large amounts are added, they can be granulated at high temperatures, resulting in sharp particle sizes. An energy-saving polymerized toner that can be fixed at a low temperature and/or at a low pressure and has a distribution can be produced.

When a water-soluble polymerization initiator is used, the moisture resistance of the polymerized toner produced decreases, and the development characteristics and blocking resistance at high temperatures deteriorate. Therefore, it is necessary to produce a polymerized toner with excellent environmental properties. For this purpose, it is preferable to use a substantially water-insoluble polymerization initiator. When using a substantially water-insoluble polymerization initiator, in a conventional system in which it is dissolved and mixed in the monomer composition in advance, the polymerization initiator is evenly distributed to each monomer composition particle. However, even in a system in which a substantially water-insoluble polymerization initiator is added after granulating the monomer composition in an aqueous medium as in the above production method, each particle undergoes a good polymerization reaction. It is surprising that this occurs.

As mentioned above, the polymerization initiator used in the above production method is preferably substantially water-insoluble. In the present invention, the substantially water-insoluble polymerization initiator means 100 ml of water at room temperature.
It has a solubility of 1 g or less per 100 g of water, preferably 0.5 g or less per 100 g of water, particularly preferably 0.2 g or less per 100 g of water. When the solubility is 1 g or more per 100 g of water, it is not preferable because decomposition products of the polymerization initiator remaining on the surface of the polymerized toner particles after completion of polymerization deteriorate the moisture resistance of the polymerized toner. In addition, the polymerization initiator used in the above production method is soluble in the polymerizable monomer, and the polymerization initiator is soluble in the entire range normally used (2 to 5 parts by weight of polymerization initiator per 100 parts by weight of monomer). It has the property of being soluble in polymerizable monomers. Polymerization initiators that can be used in the above production method include 2,2'-azobis-(2,4-dimethylvaleronitrile), 2,2'-azobisisobutyronitrile, l
, 1'-azobis(cyclohexane-1-carbonitrile), 2,2'-azobis-4-methoxy-2,4-
Azo or diazo polymerization initiators such as dimethylvaleronitrile and other azobisisobutyronitrile (AIBN); benzoyl peroxide, methyl ethyl ketone peroxide, isopropyl peroxy carbonate, cumene hydroperoxide, 2,4-dichloryl Examples include peroxide-based polymerization initiators such as benzoyl peroxide and lauroyl peroxide. In the above production method, the polymerization initiator is used at a polymerization temperature (usually 50
Those having a melting point equal to or lower than 'C or higher) are preferred. It is also preferred to use a mixture of two or more types of polymerization initiators for the purpose of adjusting the molecular weight and molecular weight distribution of the polymer or for the purpose of adjusting the reaction time.

In that case, it is preferable to use at least one type having a melting point corresponding to or lower than the temperature of the liquid in the aqueous medium during polymerization. This is because the polymerization initiator turns into an oil at the liquid temperature during the polymerization reaction, so the polymerization initiator or the radicals generated from the polymerization initiator are transferred to each monomer composition particle dispersed after being added to the aqueous medium. This is because it can be applied better. By the way, 2,2-azobis-(2,4-dimethylvaleronitrile) used in the examples below is the meso form (m, p, 55-57°
C) and the df form (m, p, 74-77°C), and the mixture starts to melt at about 45°C and melts at about 70°C.
Melting ends at °C.

The amount of the polymerization initiator used is 0.1 to 20 parts by weight, preferably 1 to 10 parts by weight, based on 100 parts by weight of the polymerized monomer. If the amount is less than 0.1 part by weight, it is difficult to apply the polymerization initiator evenly to each monomer composition particle, and if it is more than 20 parts by weight, the molecular weight of the polymerization product is low (too much and the polymerization The tendency for reactions to occur heterogeneously increases.

The suspension polymerization reaction is usually carried out at a polymerization temperature of 50° C. or higher, and the upper limit temperature is set in consideration of the decomposition rate of the polymerization initiator. If the set polymerization temperature is too high, the polymerization initiator will be rapidly decomposed, which is not preferable. In the above manufacturing method, since it is not necessary to have a polymerization initiator in the monomer composition during suspension granulation, the temperature of the aqueous medium during granulation is set to 75°C or higher, for example, to form a monomer composition. By lowering the melt viscosity of the material, granulation can be easily performed.

After confirming that the formed monomer composition particles have a predetermined particle size, the temperature of the aqueous medium containing the particles is lowered to the polymerization temperature (for example, 55 to 70°C), and then polymerization is carried out. Add initiator. By lowering the liquid temperature of the aqueous medium, the shape retention acid of the monomer composition particles is also improved, and coalescence of particles is also suppressed. The polymerization reaction time varies depending on the type of polymerization initiator and the polymerization temperature, but is usually 2 to 30 hours.

In the above production method, dispersion granulation at high temperatures is possible, so even if a large amount of a low softening point compound is added as an additive to the monomer composition, a polymerization product that can be used as a toner can be produced. is possible.

In the polymerized toner according to the present invention, the low softening point compound can also function as a binder resin. The low softening point compound in the present invention refers to the ring and ball method (JIS
Softening point measured by K 2531 etc.) is 40-13
0°C, preferably 50 to 120°C.

If the softening point is 40° C. or lower, the blocking resistance and shape retention of the toner will be insufficient, and if the softening point is 130° C. or higher, there will be little effect in lowering the fixing temperature or fixing pressure. Examples of low softening point compounds include paraffins, waxes, low molecular weight polyolefins, modified waxes having aromatic groups, hydrocarbon compounds having alicyclic groups, natural waxes, long hydrocarbon chains having 12 or more carbon atoms [CH3→CH2← -0, or -CH2
)--1□ or more aliphatic carbon chain], esters thereof, and the like can be exemplified. A mixture of different low softening point compounds may be used. Specifically, paraffin wax (manufactured by Nippon Seiro), paraffin wax (manufactured by Nippon Seiro), micro wax (manufactured by Nippon Seiro), microcrystalline wax (manufactured by Nippon Seiro), hard paraffin wax (manufactured by Nippon Seiro) , PE-130 (manufactured by Hoechst), Mitsui Hiwax 1lop (Mitsui Petrochemical), Mitsui Hiwax 220P (Mitsui Petrochemical), Mitsui Hiwax 660P (Mitsui Petrochemical), Mitsui Hiwax 210P (Mitsui Petrochemical) manufactured by Mitsui High Wax 3
20P (Mitsui Petrochemical), Mitsui Hiwax 410
P (manufactured by Mitsui Petrochemicals), Mitsui Hiwax 420P
(Mitsui Petrochemicals), Hiretsu T-100X (Mitsui Petrochemicals), Hiretsu T-200X (Mitsui Petrochemicals), Hiretsu T-300X (Mitsui Petrochemicals):
Vetrogin 80 (Mitsui Petrochemical), Vetrogin 100
(Mitsui Petrochemicals), Vetrogin 120 (Mitsui Petrochemicals), Tacace A-100 (Mitsui Petrochemicals), Tacace F-100 (Mitsui Petrochemicals), Tacace B-60 (Mitsui Petrochemicals) ), modified wax JC-1
141 (Mitsui Petrochemical), modified wax JC-213
0 (Mitsui Petrochemical), modified wax JC-4020 (
(manufactured by Mitsui Petrochemicals), modified wax JC-1142 (manufactured by Mitsui Petrochemicals), modified wax JC-5020 (manufactured by Mitsui Petrochemicals); beeswax, carnauba wax, montan wax, and the like. In addition, when using a low softening point compound having a softening point of 100° C. or higher, it may be preferable to carry out dispersion and granulation under pressure while raising the temperature of the aqueous medium to 100° C. or higher.

The above-mentioned low softening point compound controls the fixing temperature of the polymerized toner and/or
Alternatively, 50 to 3,000 parts by weight may be mixed with 100 parts by weight of a polymerizable monomer for lowering the fixing pressure. Especially from 70
Preferably, 1,000 parts by weight is mixed. If it is less than 50 parts by weight, it is insufficient to lower the fixing temperature or pressure of the fixing roller, and if it is more than 3,000 parts by weight, there is a strong tendency for blocking resistance and durability to decrease.

The polymerizable monomers that can be used to form the polymerized toner according to the present invention are monomers having a CH2=C〈 group as a reactive group, such as styrene, 0-methylstyrene, m-methylstyrene, p-methylstyrene. , p-methoxystyrene, p-phenylstyrene, p-chlorostyrene, 3
, 4-dichlorostyrene, p-ethylstyrene, 2.4
-dimethylstyrene, p-n-butylstyrene, p-t
ert-butylstyrene, p-n-hexylstyrene,
p-n-octylstyrene, p-n-nonylstyrene,
p-n-decylstyrene, p-n-dodecylstyrene,
Styrene and its derivatives such as; vinyl esters such as vinyl acetate, vinyl propionate, vinyl benzoate; acrylic acid, methacrylic acid, maleic acid, maleic acid hafester; methyl methacrylate, ethyl methacrylate, propyl methacrylate, methacrylic acid α-Methylene aliphatics such as n-butyl, inbutyl methacrylate, n-octyl methacrylate, dodecyl methacrylate, 2-ethylhexyl methacrylate, stearyl methacrylate, phenyl methacrylate, dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate, etc. Monocarboxylic acid esters; methyl acrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, propyl acrylate, n-octyl acrylate, dodecyl acrylate, 2-ethylhexyl acrylate, stearyl acrylate, acrylic Acrylic acid esters such as 2-chloroethyl acid and phenyl acrylate; Vinyl ethers such as vinyl methyl ether, vinyl ethyl ether, and vinyl isobutyl ether; Vinyl Kents such as vinyl methyl ketone, vinyl hexyl ketone, and methyl isopropenyl ketone; N- N-vinyl compounds such as vinylpyrrole, N-vinylcarbazole, N-vinylindole, and N-vinylpyrrolidone; vinylnaphthalenes; reactions such as vinyl groups such as acrylic acid or methacrylic acid derivatives such as acrylonitrile, methacrylonitrile, and acrylamide There are monomers that have a double bond. These may be used alone or in combination. A crosslinking agent may be used if necessary. As a crosslinking agent,
Examples include divinylbenzene, divinylnaphthalene, diethylene glycol dimethacrylate, and ethylene glycol dimethacrylate. The crosslinking agent additive is usually used in an amount of 0.1 to 5 parts by weight per 100 parts by weight of the polymerizable monomer. Further, a small amount of a polymer of these polymerizable monomers may be added to the monomer composition. Among the monomers mentioned above,
Styrene, styrene having substituents such as alkyl groups,
Alternatively, a polymerized toner produced from a mixed monomer of styrene and other monomers is preferable in consideration of developability and durability.

Further, a preferable polymerized toner can be obtained by adding a polar polymer having a polar group, a polar copolymer, or a cyclized rubber as an additive during polymerization of the monomer to polymerize the polymerizable monomer. The polar polymer, polar copolymer or cyclized rubber is 0.5 to 50 parts by weight per 100 parts by weight of the polymerizable monomer,
It is preferable to add 1 to 40 parts by weight. 0.5
If it is less than 50 parts by weight, it is difficult to obtain a sufficient pseudocapsule structure, and if it is more than 50 parts by weight, the amount of polymerizable monomer is insufficient and the properties as a polymerized toner tend to deteriorate (becoming a polar polymer. , suspending a polymerizable monomer composition to which a polar copolymer or cyclized rubber has been added in an aqueous phase of an aqueous medium in which the polar polymer and a dispersant having an opposite charge are dispersed, and polymerizing the composition. That is, the cationic or anionic polymer, cationic or anionic copolymer, or anionic cyclized rubber contained in the polymerizable monomer composition is preferably dispersed in an aqueous medium. The anionic or cationic dispersant and the toner particle surface are electrostatically attracted to each other, and the dispersant covers the particle surface to prevent the particles from coalescing and stabilize them, and the added polar polymer,
Since the polar copolymer or cyclized rubber gathers on the surface layer of the toner particles, they form a kind of shell-like form, and the resulting particles become pseudo-capsules. Since the relatively high molecular weight polar polymer, polar copolymer, or cyclized rubber gathered on the surface layer of the particles encapsulates a large amount of low softening point compounds inside the toner particles, the polymerized toner particles of the present invention have blocking properties. , provides excellent developability and abrasion resistance. Examples of polar polymers (including polar copolymers and cyclized rubbers) and counterloadable dispersants that can be used in the present invention are shown below. still,
The polar polymer has a weight average molecular weight of 5.0 as measured by GPC.
00 to 500,000 is preferably used because it dissolves well in the polymerizable monomer and has durability. (I)
Examples of cationic polymers include polymers of nitrogen-containing monomers such as dimethylaminoethyl methacrylate and diethylaminoethyl acrylate, copolymers of styrene and the nitrogen-containing monomers, or styrene, unsaturated carboxylic acid esters, and the like. There are copolymers with nitrogen monomers.

(n) Anionic polymers include nitrile monomers such as acrylonitrile, halogen-containing monomers such as vinyl chloride, unsaturated carboxylic acids such as acrylic acid, unsaturated dibasic acids,
There are polymers of anhydrides of unsaturated dibasic acids or copolymers of styrene and the monomer.

The dispersant is preferably an inorganic fine powder that has the ability to stabilize the dispersion of the monomer composition particles in an aqueous medium and is sparingly soluble in water. The amount of the dispersant added to the aqueous medium is preferably 0.1 to 50% by weight (preferably 1 to 20% by weight) based on water.

(m) As the anionic dispersant, Aerosil #200
There are colloidal silicas such as ゜#300 (manufactured by Nippon Aerosil Co., Ltd.).

(IV) Aluminum oxide as a cationic dispersant;
Examples include hydrophilic positively charged silica fine powder such as magnesium hydroxide, hydrophobic silica treated with a coupling agent, and aminoalkyl-modified colloidal silica.

An anionic cyclized rubber may be used instead of the above-mentioned polar polymer or copolymer.

To produce magnetic polymerized toners, magnetic particles are added to the monomer composition. In this case, the magnetic particles also serve as a coloring agent. The magnetic particles that can be used in the present invention include substances that are magnetized when placed in a magnetic field, such as iron,
Examples include powders of ferromagnetic metals such as cobalt and nickel, and powders of alloys and compounds such as magnetite, hematite, and ferrite. Magnetic fine particles having a particle size of 0.05 to 5 μm, preferably 0.1 μm in diameter are used.

The content of these magnetic particles is 10 to 60% based on the weight of the toner.
% by weight, preferably 20 to 50% by weight. Further, these magnetic fine particles may be treated with a treatment agent such as a silane coupling agent, a titanium coupling agent, or a suitable reactive resin. In this case, it depends on the surface area of the magnetic fine particles and the density of hydroxyl groups present on the surface, but it is less than 5% by weight (
A treatment amount of preferably 0.1 to 3% by weight) provides sufficient dispersibility in the polymerizable monomer and low softening point compound, and does not adversely affect the physical properties of the toner. The polymerized toner contains a colorant, and as the colorant, conventionally known dyes, carbon black, and pigments such as grafted carbon black, which is the surface of carbon black coated with a resin, can be used. The colorant is contained in an amount of 0.5 to 30% by weight based on the polymer and low softening point compound.

A charge control agent and a fluidity modifier may be added (internally added) to the toner as necessary. The charge control agent and the fluidity modifier may be used by being mixed (externally added) with the toner particles. Examples of charge control agents include metal complexes of organic compounds having carboxyl groups or nitrogen-containing groups, metal-containing dyes, and nigrosine. Examples of fluidity modifiers or cleaning aids for the surface of the latent image carrier (photoreceptor) include colloidal silica and fatty acid metal salts. Further, for the purpose of increasing the amount, fillers such as calcium carbonate and finely divided silica may be incorporated into the toner in an amount of 0.5 to 20% by weight.

Further, in order to prevent toner particles from coagulating with each other and improve fluidity, a fluidity improver such as fine Teflon powder or zinc stearate powder may be added. When a low-molecular-weight hydrocarbon compound (e.g., weight average molecular weight 500 to 5,000) or carnauba wax is used as a low-softening-point compound to improve mold releasability during hot roll fixing, for example, the hydrocarbon compound is hydrophobic and has a low softening point. Because of its molecular weight, it does not mix with the polymer produced by polymerization, and is pushed into the interior of the polymerized toner rather than coming out on the particle surface compared to polar polymers, polar copolymers, or cyclized rubber. As a result, even if it contains a large amount of a low softening point compound, it has excellent durability and blocking resistance because it is encapsulated. During fixing, it comes out from inside, significantly improving fixing properties and offset properties. In other words, it serves as an offset agent and a fixing agent. When the polymerized toner according to the present invention is applied to a two-component developer, it can be applied at a normal toner and carrier mixing ratio, for example, 1 to 500 parts by weight of carrier is mixed with 1 part by weight of toner. .

The temperature-sensitive method involves uniformly dissolving coloring agents (including magnetic substances in the present invention), 1 part by weight of a low softening point compound of 50 to 3,000 parts by weight, and additives to 100 parts by weight of polymerizable monomers. or the dispersed monomer composition in an aqueous medium containing 0.1 to 50% by weight of a suspension stabilizer (e.g., a sparingly soluble inorganic dispersant) (e.g., 5°C or higher than the polymerization temperature, preferably is heated to a temperature of 1090 to 30° C. or higher) using a conventional stirrer, homomixer, homogenizer, etc. Preferably, the particles of the molten or softened monomer composition have the desired toner particle size, generally 3.
The stirring speed, time, and temperature of the aqueous medium are adjusted so that the particles have a size of 0 μm or less (for example, a volume average particle size of 0.1 to 20 μm). Thereafter, the temperature of the aqueous medium is lowered to the polymerization temperature while stirring is performed to the extent that sedimentation of the particles is prevented, so that this state is substantially maintained by the action of the dispersion stabilizer. Polymerization temperature is 50°C or higher, preferably 55-80°C
The temperature is particularly preferably set at 60 to 75°C, and a substantially water-insoluble polymerization initiator is added while stirring to carry out polymerization. After the reaction is completed, the produced toner particles are recovered by an appropriate method such as washing, removal of the dispersion stabilizer, filtration, decantation, centrifugation, etc., and dried to obtain the polymerized toner of the present invention. In the suspension polymerization method, 200 to 200 parts by weight of water is usually added to 100 parts by weight of the polymerizable monomer and low softening point compound.
3000 parts by weight are used as aqueous dispersion medium.

Also suitable stabilizers, such as polyvinyl alcohol,
Gelatin, methylcellulose, methylhydropropylcellulose, ethylcellulose, sodium salt of carboxymethylcellulose, polyacrylic acid and their salts, starch, gum alginate, zein, casein,
Any one or a mixture of tricalcium phosphate, talc, barium sulfate, bentonite, aluminum hydroxide, ferric hydroxide, titanium hydroxide, thorium hydroxide, etc., in an aqueous medium may have an adverse effect on the production method of the present invention. It is also possible to use a substance containing only a small amount.

Further, for uniform dispersion of the inorganic dispersion stabilizer, a surfactant may be used to the extent that it does not adversely affect the production method of the present invention. This is to promote the intended action of the above-mentioned dispersion stabilizer, and specific examples thereof include sodium dodecylbenzenesulfonate, sodium tetradecylsulfate, sodium pentadecylsulfate, sodium octylsulfate, and allyl-alkyl-polymers. Sodium ethersulfonate, sodium oleate, sodium laurate, sodium caprate, sodium caprylate, sodium caproate, potassium stearate, calcium oleate, 3,3-disulfondi, phenylurea-4,4-diazo-bis- Amino-8-naphthol-
Sodium 6-sulfonate, ortho-carboxybenzene-azo-dimethylaniline, 2,2,5.5-tetramethyl-triphenylmethane-4,4-diazo-bis-
Examples include sodium β-naphthol-disulfonate and others. However, it must be noted that when a hydrophilic organic stabilizer or surfactant is used, the moisture resistance of the polymerized toner decreases.

In addition, water-soluble polymerizable monomers simultaneously cause emulsion polymerization in water and contaminate the resulting suspension polymer with small emulsion polymer particles, so water-soluble polymerization inhibitors, such as metal salts, are added. It is also good to prevent emulsion polymerization in the aqueous phase. It is also possible to add glycerin, glycol, etc. to water in order to increase the viscosity of the aqueous medium and prevent coalescence of particles during polymerization.

In addition, to reduce the solubility of easily soluble polymerizable monomers in water, N
aCl! , KCfSNa2S04 and the like may be added to the aqueous medium. It is also possible to add a Brønsted acid such as hydrochloric acid to the aqueous medium to enhance the ionization of the polar groups of the polar polymer or cyclized rubber in the monomer composition. In particular, adding a Brønsted acid such as hydrochloric acid to the aqueous medium is effective in further enhancing the effects of the anionic polymer, anionic copolymer or cyclized rubber.

The polymerized toner of the present invention can be applied to known dry electrostatic image development methods. For example, two-component development methods such as cascade method, magnetic brush method, and microtoning method; one-component development methods using magnetic toner such as conductive-component development method, insulating-component development method, and jumping development method; powder cloud method and fur brush method; non-magnetic component development method in which toner is held on a toner carrier by electrostatic force and transported to the developing section for development; electric field curtain method in which the toner is transported to the developing section and developed. It can be applied to developing methods, etc. Although it is particularly preferably applicable to dry development, it can also be used as a toner for wet development in some cases.

〔Example〕

Hereinafter, the present invention will be described in detail based on examples.

Practical JE Example 2 Styrene monomer 2000 parts by weight Cyclized rubber (Alpex CR450° manufactured by Hoechst Japan) 400 parts by weight Bontron E81 (charge control agent).

Orient Chemical Industry Co., Ltd.) 80 parts by weight Carbon black (STERING R.

A monomer composition was prepared by mixing the above components with an attritor at a temperature of 80°C for 4 hours. 254 parts by weight of the obtained monomer composition were mixed with 20 parts by weight of amino-modified silica (100 parts by weight of Aerosil 200 treated with 5 parts by weight of aminopropyltriethoxysilane) and 0.5 parts by weight. The mixture was poured into an aqueous medium of 1200 parts by weight of distilled water heated to 85° C. containing 25 parts by weight of IN hydrochloric acid under stirring using a TK homomixer, and then stirred at 10.00 rpm for 15 minutes to perform dispersion and granulation.

After granulation, the liquid temperature was lowered to 60°C, and 3 parts by weight of 2.2'-azobis-(2,4-dimethylvaleronitrile) and 1.2 parts by weight of 2,2'-azobisisobutyronitrile were added as polymerization initiators.
5 parts by weight were added to the aqueous medium and stirred for 30 minutes. Furthermore, the stirring was changed to paddle blade stirring, and the mixture was stirred at 60°C for 10 hours to complete the polymerization.

The obtained aqueous medium containing the polymerized toner is cooled and dehydrated,
Wash with sodium hydroxide solution to dissolve and remove amino-modified silica, wash with water, dehydrate, and dry (classify if necessary to remove fine particulate unnecessary component particles) Volume average particle size: 6. A polymerized toner of 5 μm (measured with a Coulter counter using a 100 μm aperture) was obtained. The obtained polymerized toner contained about 180 parts by weight of paraffin wax based on 100 parts by weight of polystyrene. Further, even when the obtained toner was left in an environment of 50° C. for one day, no blocking occurred. From this, it was found that paraffin wax was encapsulated inside the polymerized toner particles.

Total weight of the obtained polymerized toner lO, 0.1 part by weight of zinc stearate powder, 0.1 part by weight of hydrophobic silica (Aerosil R972° manufactured by Nippon Aerosil Co., Ltd.), and an average particle size of 40
A developer was prepared by mixing 90 parts by weight of micrometer insulating carrier particles (formed from 75 parts by weight of triiron tetroxide and 25 parts by weight of epoxy resin), and developed under the following conditions.

Transferred and fixed.

Photoreceptor・・・・・・・・・・・・・・・・・・・・・
Amorphous silicon photoreceptor copy speed...
・・・・・・・・・270mm/see Electrostatic latent image forming conditions Dark potential・・・・・・・・・・・・・・・・・・＋
450v sleeve diameter 32mm
(Peripheral speed 270mm/sec) Magnetic flux density in the vertical direction of the sleeve surface of the magnetic N and S magnetic poles...
・・・・・・1000 Gauss Thickness of developer layer・・・・・・
・・・・・・・・・・・・・・・・・・・・・・・・
・・・・・・・・・・・・・・・0, 2 mm Distance between sleeve and photoreceptor surface ・・・・・・・・・・・・3
00μm development bias・・・・・・・・・・・・・・・
・・・・・・－・・・・・・・・・・・・＋200v
(DC) 3.0KHz, 1.4KVpp (AC) Transfer conditions (from drum to intermediate transfer body) Intermediate transfer body material・・・・・・・・・・・・・・・・・・
・・・・・・RTV silicone rubber (thickness 1 mm) Intermediate transfer body surface roughness ・・・・・・・・・・・・・・・・・・
・・・・・・・・・・・・4μm RM S transfer pressure...
・・・・・・・・・・・・・・・・・・・・・・・・
・・・・・・・・・・・・・・・・・・・・・・・・
・・・・・・・・・I Kg/crd intermediate transfer body temperature・
・・・・・・・・・・・・・・・・・・・・・・・・
・・・・・・・・・・・・・・・・・・・・・・・・5
0°C transfer/fixing conditions (from intermediate transfer body to transfer paper) Transfer pressure・・・・・・・・・・・・・・・・・・・・・・・・
・・・・・・・・・・・・・・・・・・・・・・・・
・・・・・・・・・30 Kg/crtr Pressure/heating roller temperature・・・・・・・・・・・・・・・・・・・・・
......110'C nip width...
・・・－・・・・・・・・・・・・・・・・・・・・・
・・・・・・・・・・・・・・・・・・・・・・・・
......3mm results are shown below.

K on the lid'' Instead of 3500 parts by weight of paraffin 155°F, 500 parts by weight of paraffin wax 140°F (softening point 60°C) and 200 parts by weight of paraffin 155° (softening point 69°C)
0 parts by weight, and the liquid temperature of the aqueous medium during dispersion granulation was set to 90%.
A polymerized toner having a volume average particle size of 5.8 μm was produced in the same manner as in Example 1 except for changing to 'C.
It contained about 125 parts by weight of paraffin wax per 100 parts by weight of polystyrene.

A monomer composition was prepared by mixing the above components in an attritor for 4 hours. Separately, 20 parts by weight of amino-modified silica, 0. I
An aqueous medium consisting of 25 parts by weight of N-hydrochloric acid and 1200 parts by weight of distilled water was heated to 75°C, and 254 parts by weight of the above monomer composition was added to the aqueous medium under stirring with a TK homomixer,
After injection 10. After stirring at OOQ rpm for 30 minutes, the aqueous medium was cooled to 60° C. after granulation. As a polymerization initiator, 2,2
'-Azobis-(2,4-dimethylvaleronitrile)5
Parts by weight and 2,2'-azobisisobutyronitrile 2
After adding the parts by weight, the mixture was further stirred for 30 minutes. After that, stir with a regular stirrer at a rotation speed of 1100 rpm for 60 minutes.
'C for 10 hours. Thereafter, post-treatment was carried out in the same manner as in Example 1, and a polymerized toner with a sharp particle size distribution and a volume average particle diameter of 5.5 μm was obtained. The obtained polymerized toner contained about 55 parts by weight of paraffin wax based on 100 parts by weight of polystyrene.

The above components were mixed using an attritor at a temperature of 60° C. for 4 hours to prepare a monomer composition.

6 parts by weight of 2,2-azobis-(2,4-dimethylvaleronitrile) and 3 parts by weight of 2,2'-azobisisobutyronitrile were added to 254 parts by weight of the obtained monomer composition. The mixture was mixed with amino-modified silica (Aerosil 2).
00 (100 parts by weight treated with 5 parts by weight of aminopropyltriethoxysilane) and 20 parts by weight of 0. IN
Distilled water heated to 60°C containing 25 parts by weight of hydrochloric acid 1
The mixture was added to 200 parts by weight of an aqueous medium under stirring using a TK homomixer, and after the addition, the mixture was stirred at 10,000 rpm for 15 minutes to perform dispersion and granulation.

Furthermore, the stirring was changed to paddle blade stirring, and the mixture was stirred at 60° C. for 10 hours to complete the polymerization. Next, post-treatment was carried out in the same manner as in Example 1 to obtain a polymerized toner having a volume average particle diameter of 5.3 μm. The obtained polymerized toner contained about 20 parts by weight of paraffin wax based on 100 parts by weight of polystyrene. 10 parts by weight of the obtained polymerized toner, 0.1 parts by weight of zinc stearate powder, hydrophobic silica (Aerosil R97)
2. Carrier particles (manufactured by Nippon Aerosil Co., Ltd.) 0.1 part by weight and an average particle size of 40 μm (same as in Example 1) 9
A developer was prepared by mixing 0 parts by weight. When development, transfer, and fixing were performed in the same manner as in Example 1 using the prepared developer, a fixed image that could be used for practical purposes was obtained at a fixing temperature of 190° C. or higher. Furthermore, the fixing roller temperature is 100'C.
, 120° C., and 140° C., the fixing was insufficient and no fixed image usable for practical use was obtained.

The above components were mixed using an attritor at a temperature of 60° C. for 4 hours to prepare a monomer composition.

0.5 parts by weight of 2,2'-azobis-(2,4-dimethylvaleronitrile) and 0.2 parts by weight of 2,2-1azobisisobutyronitrile were added to 254 parts by weight of the obtained monomer composition.
20 parts by weight of amino-modified silica (100 parts by weight of Aerosil 200 treated with 5 parts by weight of aminopropyltriethoxysilane) and 0.0 parts by weight were added and mixed. The mixture was added to an aqueous medium containing 25 parts by weight of IN hydrochloric acid and 1200 parts by weight of distilled water heated to 60°C under stirring using a TK homomixer, and after the addition, the mixture was stirred at 10.00 rpm for 15 minutes to perform dispersion and granulation. .

Furthermore, the stirring was changed to paddle blade stirring, and the mixture was stirred at 60° C. for 10 hours to carry out polymerization. Subsequently, when post-processing was carried out in the same manner as in Example 1, there were many particles with a particle size of 100 μm or more, so that the toner could not be put to practical use as a toner for developing electrostatic images as it was. Therefore, although particles having a volume average particle diameter of about 8 μm were obtained by classification, the blocking resistance was insufficient.

(Effects of the Invention) Since the present invention uses the above-described apparatus and developing material,
Since electrostatic transfer means are not used for transfer, it is possible to prevent image distortion and loss of clarity due to the weak adhesion of toner to the transfer material, and prevent excessive pressure from being applied to the photoreceptor during transfer. At the same time, it is possible to transfer and fix at a temperature far lower than the melting point of the developing material under normal pressure, which sufficiently suppresses the rise in temperature of the photoreceptor and prevents changes in characteristics ((
Therefore, its lifespan can be greatly extended, and high-quality images can be stably obtained over a long period of time.

[Brief explanation of the drawing]

FIG. 1 is a schematic side view showing an image forming apparatus according to an embodiment of the present invention, and FIG. 2 is a side view schematically showing another embodiment of the present invention. l・・・・・・・・・・・・・・・・・・Photoreceptor,
20・・・・・・・・・・・・・・・・・・Intermediate transfer body, 3・・・・・・・・・・・・・・・Pressure body, N,
, N2......Nip section.

Claims (2)

[Claims] (1) The electrostatic latent image formed on the photoreceptor is developed using a developer to form a toner image, the formed toner image is pressure-transferred to an intermediate transfer member that is in pressure contact with the photoreceptor, and then this In an image forming method for obtaining a fixed image by transferring and fixing the transferred toner image onto a transfer material passing between the intermediate transfer body and a pressure body that is in pressure contact with the intermediate transfer body, the toner image is The toner to be formed is a polymerized toner containing 50 to 3000 parts by weight of a low softening point compound having a softening point of 40 to 130°C based on 100 parts by weight of a polymer formed from a polymerizable monomer, and the intermediate transfer The image transferred to the body is transferred to a transfer material passing between the intermediate transfer body and the pressure body under conditions of pressure and temperature higher than the pressure contact force between the photoreceptor and the intermediate transfer body, and An image forming method characterized by fixing. (2) Formed from a polymerizable monomer in an image forming apparatus equipped with a photoreceptor for forming an electrostatic latent image and an intermediate transfer member for pressure-transferring the toner image formed on the surface of the photoreceptor. softening point of 40 to 100 parts by weight of the polymer
Pressed against the intermediate transfer body for transferring the toner image on the intermediate transfer body formed from a polymerized toner containing 50 to 3000 parts by weight of a low softening point compound at 130° C. to a passing transfer material. A pressure member is provided, the pressure member is in pressure contact with the intermediate transfer member with a pressure contact force greater than the pressure contact force between the photoreceptor and the intermediate transfer member, and heats and fixes the toner. An image forming apparatus characterized in that it includes a heating means for heating.