JPS5977468A - Recording method - Google Patents

Abstract

PURPOSE:To realize high-speed copying operation and to obtain an image with good transfer efficiency and high fidelity with a simple and small-sized device, by using toner with specific nature for transfer to a transfer material after transferring insulating magnetic toner from an image holder such as an electrophotographic receptor to an intermediate transfer body. CONSTITUTION:A toner image T on a photosensitive drum 1 is transferred onto an intermediate transfer belt 5 in a transfer area A by a pressure roll 6 and the toner transferred to a cohesive layer made of silicone rubber, etc., of the belt 5 is transferred repeatedly in a transfer and fixation area C by a roll 7 incorporating a heat roll 7A by using a device which performs transfer to the transfer material P by a press-contacting roll 9. The toner in use is insulating magnetic toner which has <=10<-13>v/cm conductivity and a >=5 deg.C difference between a softening point and a softening starting point. Toner which contains polyolefin with an 80-180 deg.C softening point is specially used. Consequently, high-speed copying operation is possible and a copy of superior quality which is stable even in a high-humidity atmosphere and has high transfer efficiency and no offset is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a recording method, such as an electrophotographic copying method, an electrostatic recording method, and the like.

In the conventional electrophotographic method, the following steps 1 to 2 are repeated. That is, (1) Charging step: A photoreceptor having a photoconductive substance is generally charged by an electrical method (corona generating device). ■Exposure process: 1. An electrostatic latent image is created by shining light through the original. ■Developing process:
A toner is attached to the electrostatic latent image to visualize it. ■Transfer step: Transfer the developed image onto a recording member (for example, copy paper).

■Fixing step: The transferred image on copy paper is fixed using heat and/or pressure. ■Cleaning process: Removes developer remaining on the photoreceptor.

Currently, in the transfer process, an electrostatic transfer method using a corona generating device is generally used.

In this method, an electric charge having a polarity opposite to that of the toner of the developed image on the photoreceptor to which the toner is attached is applied to the copying paper by corona discharge, and the toner is attracted and transferred in a non-contact manner. In this case, the amount of power required to effect image transfer is determined by many variables. Therefore, a lot of consideration needs to be taken in setting up the device, which makes the device complicated. The electrostatic transfer method is not always efficient because of the large attraction force between the toner and the photoreceptor, and the disturbance of the electric field prevents faithful transfer of the developed image.

As a result, the image quality becomes poor, with a low degree of blackening, poor gradation, and poor clarity. Moreover, since some toner remains on the photoreceptor with a force greater than the electrostatic attraction force, a process is required to completely remove the residual toner on the photoreceptor.
Problems arise in that the number of processes increases and the machines become more complex.

The transfer process is not a non-contact method as described above, but a contact method using an intermediate transfer body. Special Public Service No. 46-41679
The publication discloses a method of transferring toner on a photoreceptor to a silicone rubber intermediate transfer member by pressing, and then immediately applying heat energy sufficient to melt the toner and transferring the toner to transfer paper. has been done. Special public Sho 4B-22763
The publication discloses a method in which toner is adhered to a silicone rubber surface and transferred and separated onto a transfer medium such as paper. Japanese Unexamined Patent Publication No. 49-78559 discloses a method in which toner on an intermediate transfer member is heated and fixed by pressure on a transfer paper.

Japanese Patent Application No. 55-73865 discloses that a developed image made of conductive magnetic toner formed on a photoreceptor is transferred under pressure to an intermediate transfer member, and this developed image is thermally pressed, transferred and fixed onto a recording member. An image forming method is disclosed.

In the transfer process, in addition to such improvements in devices, attempts have also been made to improve materials. For example, there are resin-coated coated papers and toners with different conductivity.

Toners can generally be broadly classified into one-component type and two-component type.

The one-component developer has the following advantages compared to the two-component developer.

■No need to adjust developer concentration.

■Simplification and downsizing of equipment.

■Long maintenance cycle.

In addition, the one-component developer is an insulating magnetic toner that has a relatively high electrical resistance (especially a resistivity of 10'3 Ω-m or more) and an insulating magnetic toner that has a relatively low electrical resistance (especially a resistivity of 104 to 108 Ω-σ).
It can be classified as a conductive magnetic toner.

Since conductive toner develops based on electrostatic induction of latent image charges, the toner does not require a true charge. On the other hand, insulating toner has a true charge due to frictional charging and the like, and development proceeds due to the electric attractive force between the true charge of the toner and the latent image charge. Due to these essential differences, conductive toner cannot be developed at high speed in the development process, and since the toner is developed in a single layer, the degree of blackening is low and the image quality is poor in gradation.

Moreover, the transfer process is highly dependent on humidity.
In the case of electrostatic transfer using a corona generating device, the toner forms a conductive path and leaks the charge on the photoreceptor and the charge of corona discharge, resulting in poor transferability even in normal humidity.

On the other hand, insulating toner can be used by adjusting the amount of charge. )
It is possible to develop multiple layers of toner, and development with a high degree of blackening is possible. Also, in the transfer process, since the toner has a true charge, so-called "repulsion" occurs due to corona discharge.
Difficult to faithfully transcribe. Moreover, the transfer efficiency is 70-9
0%, which causes problems such as a decrease in image density and processing of residual toner.

An object of the present invention is to provide an image forming method that allows high-speed copying.

Another object of the present invention is to provide an image forming method capable of forming a stable high quality image that is not affected by a high humidity atmosphere.

Another object of the present invention is to provide an image forming method with high transfer efficiency and faithful latent image formation.

Another object of the present invention is to provide an image forming method that provides stable running properties without causing an offset phenomenon and that also provides good image quality.

Still another object of the present invention is to provide an image forming method that can simplify and downsize a copying apparatus.

Each of the above objects is achieved by the recording method of the present invention, that is, forming a latent image on an image carrier such as a photoreceptor drum, developing this latent image with an insulating magnetic toner to form a visible toner image, This is achieved by a recording method characterized by transferring this toner image onto an intermediate transfer member such as a belt or roll, and further transferring (further fixing) this transferred toner image onto a transfer material such as copy paper. Ru.

According to the recording method of the present invention, since an insulating magnetic toner is used for development, it is possible to exhibit the characteristics of the one-component insulating toner as described above, and also to use the insulating magnetic toner. The disadvantage of poor transferability is effectively overcome by applying an intermediate transfer method that does not require electrostatic force. The intermediate transfer method forcibly transfers the toner image on the image carrier onto a contact-type intermediate transfer member, and then physically transfers the transferred toner image onto the transfer material. The true charge possessed by the material can be transferred without substantially affecting the transfer characteristics, and the transfer efficiency can be improved.

In particular, the method of the invention provides a conductivity of 1.0" U/
It is desirable to use an insulating magnetic toner with a size of 1 cm or less for development. Further, when an insulating magnetic toner having a difference between the softening point and the softening start point of 5° C. or more is used for development, offset development (offset between the intermediate transfer member and the transfer material) can be completely reduced. The offset prevention effect has a softening point of 80 to 18
It can also be obtained by using an insulating magnetic toner containing polyolefin at 0° C. for development.

Hereinafter, the present invention will be illustrated in detail with reference to the drawings.

FIG. 1 shows a recording apparatus using a belt-shaped intermediate transfer member. In this recording device, a known latent image forming mechanism 2, a developing mechanism 3, and a cleaning mechanism 4 are sequentially provided in the rotation direction in a region along the outer peripheral surface of a toner image holding body 1 such as a rotating drum type photosensitive drum. It is being

In the transfer area A between the developing mechanism 3 and the cleaning mechanism 4, an intermediate transfer member 5 made of an endless belt is applied to the outer peripheral surface of the toner image carrier 1 by a pressure (transfer) roll 6 at a rate of about 0.15 kg/cnt, for example. Pressed down by pressure.

At the time of this suppressed transfer, consideration must be given so that the squeeze vector for the three-dimensional toner particle accumulation is minimized. The intermediate transfer belt 5 is made of a flexible film substrate made of polyimide or the like having a thickness of 10 to 100 .mu.m and coated with an adhesive layer of silicone rubber having a thickness of 10 to 100 .mu.m, for example. This transfer layer may be made of natural rubber, urethane rubber, styrene-butadiene rubber, ethylene-propylene rubber, fluororubber, etc. in addition to silicone rubber. The intermediate transfer belt 5 includes a pressure roll 6, a heating roll 7, and a tension roller 8.
The rack is then moved in the transfer area A at a constant speed in the same direction as the toner image holding member 1, and is directed to the intermediate transfer member heating area B on the heating roll 7.

Further, a cleaning roller 12 is disposed opposite to the tension roller 8, and a charge eliminating member 13 such as a charge eliminating brush that prevents the belt 5 from being charged is further provided.

In the transfer and fixing area C at or near the separation point of the intermediate transfer belt 5 on the heating roll 7 , a pressure roll 9 is provided so as to be pressed against the roll 7 . A transfer material heating plate 10 is placed along a transfer material heating area immediately before the transfer fixing area C in a transfer material moving path P of the transfer material constituted by a recording sheet, which is set to pass through the transfer fixing area C. is located.

Using the apparatus configured as described above, in this example, the toner image formed on the toner image holding member 17 is finally transferred and fixed onto a transfer material in the following manner.

First, the toner image T on the toner image holding member 1 is formed by developing a latent image formed by the latent image forming mechanism 2 with the developing mechanism 3. That is, when electrophotography is used, the toner image carrier 1 is composed of a selenium-based, organic compound-based, zinc oxide or cadmium sulfide-based binder type, or other electrophotographic photoreceptor, and has a latent image forming mechanism. 2, an electrostatic latent image is formed by charging the entire outer peripheral surface of the toner image carrier 1 and then performing image exposure. In addition, when using electrostatic recording, the toner image carrier 1 is composed of a dielectric material consisting of a conductive base and a dielectric surface layer, and the image signal is electrostatically transferred using a multi-starlice electrode or an ion control electrode. A latent image is formed by converting it into a latent image. Further, when a magnetic recording method is used, the toner image carrier 1 may be made of a magnetic material, and an image signal may be converted into a magnetic signal by a magnetized head to form a magnetic latent image.

If the latent image formed in this way is an electrostatic latent image, the developing mechanism 3 generates an insulator, which is colored charged particles triboelectrically charged to the opposite polarity to the charge forming the latent image. A visible image is created using magnetic toner.

The toner image T on the toner image carrier 1'' formed as described above is transferred onto the intermediate transfer belt 5 in the transfer area A by the pressing force of the pressing roller 6.

The adhesive layer of the intermediate transfer belt 5, especially the silicone rubber layer,
At a low temperature, the toner image carrier 1 is transferred to the transfer area A due to the appropriate tackiness of the surface and the rubber elasticity containing l-toner.
It is possible to overcome the toner retention force of the intermediate transfer member and sufficiently capture toner on the intermediate transfer member side. In addition, since the surface energy of the silicone rubber layer is sufficiently lower than that of ordinary transfer material, in the transfer fixing area C, which will be described later,
When the toner is heated from the transfer material side surface and is pressed against the transfer material in a fluid state, the toner strongly adheres to the transfer material and is almost completely transferred and fixed to the transfer material. Become so.

The heating roll 7 has a heater 7A made of, for example, an infrared lamp built into a hollow metal roll made of aluminum or the like, and controls the temperature of the surface of the metal roll within an appropriate range. This heats the intermediate transfer belt 5 and its second toner image T in the area between the contact start point E with the intermediate transfer belt 5 and the transfer fixing area C, that is, the intermediate transfer body heating area B, The transfer and fixing properties of the toner image in area C are made to be sufficient. The pressure roll 9 in the transfer fixing area C is configured as an auxiliary heating roll to further improve transfer fixing properties, and is a heat-resistant elastic roll provided with a surface layer of silicone rubber or the like and equipped with a built-in heater lamp 9A. Ru. Further, the transfer material heating plate 10 in the illustrated example has a shape adapted to contact along the outer layer surface of the pressure roll 9, and the transfer material is transferred between the surface of the pressure roll 9 and the transfer material heating plate 10. When the intermediate transfer member 5 is passed through the transfer material, the transfer material heating plate 10 contacts and heats the surface of the intermediate transfer member 5 in the transfer fixing area C to such an extent that the toner image on the intermediate transfer member 5 is sufficiently transferred and fixed to the transfer material.

Here, the friction coefficient of the surface of the pressure roll 9 is equal to that of the transfer material heating plate 1.
Therefore, as the surface moves due to the rotation of the pressure roll 9, the transfer material slides on the surface of the fixed transfer material heating plate 10 and is heated by contact, and is transferred to the transfer fixing area C. transported.

In the transfer fixing area C, the transfer material heated in this way is sandwiched and pressed between the intermediate transfer belt 5, which has been heated together with the toner image by the heat roll 7, and the pressure roll 9, whereby the Since the toner of the toner image is heated and pressed in a fluidized state, it is reliably transferred and fixed onto the transfer material.

The transfer material that has passed through the transfer fixing area C is normally conveyed along the intermediate transfer belt 5 and separated from the intermediate transfer belt 5 by a tension roller 8 .

Here, if the diameter of the tension roller 8 is made small, it is possible to easily separate the transfer material from the intermediate transfer belt 5, but by making it swing further, the biasing of the intermediate transfer belt 5 can be prevented. You can also do that. The intermediate transfer belt 5 that has passed through the transfer and fixing area C is partially naturally cooled, undergoes transfer again in the transfer area A, and is further transferred to the transfer and fixing area C.
Repeat the transfixing process at .

In the figure, reference numeral 11 denotes a cleaning roller, which removes toner when it adheres to the pressure roll 9.

In addition, in the transfer method shown in FIG. 1, since the intermediate transfer belt 5, the toner, and the transfer material are heated together, it is possible to reduce the heating temperature required for each of them. It is no longer necessary to excessively heat each component, and the amount of heat dissipated can be suppressed to a small level, greatly improving the overall heat utilization efficiency. This makes it possible to significantly reduce total energy consumption. can. Further, it becomes possible to transfer and fix toner images at high speed. In addition, since the intermediate transfer belt 5 is not heated excessively, even if the toner image carrier 1 has a basic property sensitive to heat, such as a photoconductive photoreceptor, its good properties can be maintained. It is possible to prevent problems such as when some of the material components of the intermediate transfer belt 5 adhere to the toner image carrier 1, and the intermediate transfer belt 5 is not heated to a high temperature. Moreover, since it is not exposed to severe temperature changes, its durability can be maintained for a long period of time, or the heat resistance conditions required for the material of the intermediate transfer belt 5 are relaxed, and the selection of the material is The range is expanded and costs can be reduced. Further, the toner is not heated excessively, and image blurring or offset phenomena due to excessive fluidity of the toner do not occur. In addition, the transfer material is not excessively heated, thermal deformation and wrinkles of the transfer material do not occur, and of course, there is virtually no risk of fire.

FIG. 2 shows an example in which the intermediate transfer member is of a roll type, and parts common to the above-described example are given common reference numerals and explanations are omitted.

In this example, the intermediate transfer roll 5, which has an adhesive layer such as silicone rubber as a transfer layer on a metal roll base, is used within the allowable range of the structural strength of the three-dimensional toner particle accumulation, for example, 0.
It is pressed against the drum 1 with a pressure of 1 kg/c/L. A pressure roll 9 is brought into pressure contact with the roll 5 from below,
Both rolls 5.9 are equipped with heaters 25A and 9A as described above.
are built-in respectively. A method using such an intermediate transfer roll has the advantage that the structure is much simpler than the intermediate transfer belt method, and the temperature of the roll can be easily controlled.

According to the recording apparatus shown in FIG. 1 or 2 above, since contact transfer is performed using an intermediate transfer body without relying on electrical action as in the electrostatic transfer method, there is no disturbance of the transferred latent image in the transfer process. . Therefore, good image quality without "bleeding" or "splashing" can be obtained. By adjusting the contact strength of the intermediate transfer member to an appropriate level, it is possible to transfer the toner to the intermediate transfer member and further to copy paper without destroying the three-dimensional cumulative structure of the toner.

Therefore, soft fixing that improves the degree of blackening is possible.

Furthermore, even in the contact method using an intermediate transfer member, the transfer efficiency is influenced by the conductivity of the toner. This seems to be related to the interaction between the intermediate transfer member and the toner as well as the interaction between the toners. Transfer efficiency is as follows: toner conductivity is 10-1
When 3 to 1o-30U/cIrt, preferably 101
It becomes good when it is 3 to 1o-18o/α.

If it is more than 10-+3 U/cm, the developing performance will be poor, and if it is less than 10-''U/cm, the toner will have strong cohesiveness and poor conveyance in the developing device.

Here, the conductivity of the toner is measured by placing the sample in a measuring cell with a constant cross-sectional area (Fi) to a depth of 0.03 to 0.08 cm.
CTL), apply a load of 1) to the top surface, and measure the current value (iA) when the applied voltage (Vvolt) is changed. The characteristics of the toner are defined by the conductivity at a voltage of 1000 V/CWL.

The magnetic toner according to the present invention is particularly preferably one in which the difference between the softening point and the softening start point is 5° C. or more. For toners with a difference between the softening point and the softening start point of less than 5°C, when forming images continuously, thermal transfer conditions may vary due to fluctuations in the temperature and humidity conditions of the atmosphere, fluctuations in the heating temperature of the image forming device, etc. This is because the image quality constantly changes and it is difficult to obtain good image quality. For example, the viscoelasticity of the toner transferred and fixed changes due to temperature changes during thermal transfer, and the softened toner is not sufficiently transferred to the copy paper and remains on the intermediate transfer member, and this residual toner is transferred to the photoreceptor or the next transfer member. A so-called offset phenomenon occurs when the toner is retransferred to the transferred transfer paper, etc., which deteriorates the image quality, or the toner is insufficiently fixed during thermal transfer, or conversely, it becomes overly fixed, which deteriorates the image quality. . In the magnetic toner according to the present invention, by considering the type of material used and the number of parts added, the difference between the softening point and the softening start point can be controlled to 5° C. or more, and good image quality can be obtained.

The softening point is measured using a Koka type flow tester (manufactured by Shimadzu Corporation) under the following conditions: load 20 kg/d, nozzle diameter 1
mm, the length of the nozzle is 1 blade, and the temperature increase rate is 6°C/min,
When measuring and recording under the condition that the sample amount of magnetic toner is 1-, when the height of the S-curve in the plunger drop-temperature curve (softening flow curve) of the float tester is h, 2
The temperature at h. Also, the temperature at h/10 is called the softening start point.

The toner according to the present invention preferably contains a polyolefin having a softening point of 80 to 180°C. Assuming that the temperature of the recording member (generally copy paper) during transfer and fixing is between the toner softening point and the softening start point, when the difference between the two temperatures is small, the state of the toner (
For example, the viscoelasticity) fluctuates greatly, and as a result, an offset phenomenon tends to occur, leading to deterioration of image quality. This problem can be solved by setting the difference between the 'softening point' and the softening start point to 5° C. or more, as described above.

However, the problem can also be solved by including a polyolefin having a softening point of so-xsO<0>C.

Although the reason for this is not clear, it is effective in reducing the offset phenomenon and preventing deterioration of the intermediate transfer member.

These polyolefins are JISK-2531-19
Softening point 80~ measured by the ring and ball method specified in 60
Any polyolefin may be used as long as it has a temperature of 180°C, and these polyolefins may be used alone or in combination of two or more types. If a polyolefin having a softening point of less than 80° C. is used, the softening point and glass transition point of the toner will be excessively lowered, resulting in a blocking phenomenon during storage, which is undesirable. Furthermore, if the softening point exceeds 180°C, the softening point will rise excessively, making it difficult for the polyolefin to melt during fixing, and as a result, it will not be able to exhibit its offset prevention function, making it impossible to achieve the purpose. The amount of polyolefin used in the present invention is not particularly limited, but is 11 to 65% by weight (more preferably 0.2 to 20% by weight) based on the total amount of toner.
% by weight). Further, the softening point of the polyolefin is preferably 80 to 180°C, more preferably 130 to 160°C.

Specific examples of such polyolefins include polyethylene, polypropylene, polybutylene, etc. Among these, polypropylene is particularly preferred.

The polyolefins effectively used in the present invention include:
Contains olefin copolymers. Such an olefin copolymer is an olefin copolymer containing only olefin as a monomer component, or an olefin copolymer containing something other than olefin as a monomer component, and has a relatively low softening point. . Here, the olefin as a monomer component includes:
For example, ethylene, propylene, butene-1, pentene-
1, hexene-1, heptene-1, octene-1, nonene-1, decene-1, and their isomers with different positions of the unsaturated bond, as well as e.g. 3-methyl-1-butene, 3-methyl -2-Pentene, 3-propyl-5-methyl-2-hexene, etc., which have branched chains composed of alkyl groups, and all other olefins are included. Examples of monomers other than olefins that form copolymers with olefins include vinyl ethers such as vinyl methyl ether, vinyl-n-butyl ether, and vinyl phenyl ether; for example, vinyl acetate and vinyl butyl ether; Vinyl esters such as vinyl fluoride, vinylitine fluoride, tetrafluoroethylene, vinyl chloride, vinylidene chloride, and haloolefins such as tetrachloroethylene; such as methyl acrylate, ethyl acrylate, n-butyl acrylate, methyl methacrylate, ethyl methacrylate,
Acrylic esters or methacrylic esters such as 11-butyl methacrylate, stearyl methacrylate, N,N-dimethylaminoethyl methacrylate, and t-butylaminoethyl methacrylate;
For example, acrylic acid derivatives such as acrylonitrile and N,N-dimethylacrylamide; organic acids such as acrylic acid, methacrylic acid, maleic acid, fumaric acid, itaconic acid, diethyl fumarate, β-pinene, and various others. I can do it.

Therefore, the olefin copolymer that can be used in the present invention is an olefin copolymer consisting only of olefins containing at least two or more of the above-mentioned olefins as a monomer component, such as ethylene-propylene copolymer, ethylene -Butene copolymer, ethylene-pentene copolymer, propylene-butene copolymer, propylene-
Pentene copolymer, ethylene-3-methyl-1-butene copolymer, ethylene-propylene-butene copolymer, etc.
Or an olefin copolymer containing as a monomer component at least one of the above olefins and at least one monomer other than the above olefins, such as ethylene-vinyl acetate copolymer, ethylene-vinylmethyl Ether copolymer, ethylene-vinyl chloride copolymer,
Ethylene-methyl acrylate copolymer, ethylene-methyl methacrylate copolymer, ethylene-acrylic acid copolymer, propylene-vinyl acetate copolymer, propylene-vinylethyl ether copolymer, propylene-ethyl acrylate copolymer, Propylene-methacrylic acid copolymer, butene vinyl methyl ether copolymer, butene-methyl methacrylate copolymer, pentene-vinyl acetate copolymer, hexene-vinyl butyrate copolymer, ethylene-propylene-vinyl acetate copolymer polymer, ethylene-vinyl acetate-vinyl methyl ether copolymer, etc. Among the above-mentioned olefin copolymers, those containing monomers other than olefins as monomer components are preferably copolymers containing a large amount of olefin components.

As the magnetic material used in the magnetic toner according to the present invention, commonly used magnetic powders can be used. Specifically, metal powders such as cobalt, iron, and nickel, aluminum, copper, manganese, magnesium, bismuth, lead,
Alloys of the metals tin, zinc, titanium, cadmium, chromium, iron, nickel, and cobalt, their oxides, mixtures of these oxides, and intermetallic compounds containing these, based on the total amount of l. A blending ratio of 10 to 80% by weight, preferably 35 to 65% by weight is good. Some of these magnetic materials exhibit effects as conductive substances or colorants, in which case the toner of the present invention achieves the purpose of the present invention without the addition of any particular conductive substance or colorant. The surface of these magnetic materials may be modified with titanium, a silane coupling agent, or the like.

Depending on the type of magnetic material, the softening point and softening start temperature of the toner will differ even if the same resin is used.

This originates from the difference in bonding force or affinity between the magnetic material and the resin, and this difference is influenced by the amount of oil absorbed by the magnetic material. Therefore, by mixing two or more types of magnetic materials with different oil absorption amounts, it is possible to produce a toner having a difference between the softening point and the softening start temperature of 5° C. or more.

In order to prevent an increase in the softening point of the toner, the oil absorption amount of the magnetic material is preferably 10 to 80 m17100 g, and there is no particular limit to the difference in oil absorption between two or more types of magnetic materials used, but it is recommended that the oil absorption amount be 5 m171009 or more. Friendly.

The binder resin used in the magnetic toner of the present invention is preferably a thermoplastic resin, such as polystyrene, polyvinyltoluene, styrene-butadiene copolymer, styrene-acrylic copolymer, styrene-maleic anhydride. Polymers or copolymers of styrene or its substituted products such as copolymers, polyester resins, acrylic resins, xylene resins, ionomer resins, ketone resins, terpene resins, phenol-modified terpene resins, rosin, rosin-modified resins, maleic acid Modified phenol resin, petroleum resin, starch graft polymer, polyvinyl alcohol, polyvinylpyrrolidone, etc. are used alone or in combination in an amount of 30 to 65% by weight based on the total amount of the toner. In the present invention, styrene resins and polyester resins are particularly preferred.

The colorant used in the magnetic toner according to the present invention includes:
Conventionally known blacks such as carbon black, aniline black, channel black, and acetylene black may be used, and they are used in an amount of 0 to % weight based on the total amount of the toner. Colorants have the advantage of improving image density and gloss as the amount added increases, but since the softening point of the toner also increases, the upper limit is determined by this.

Additionally, a fluidity improver can be used. Specifically 5
i02, Ti0z, M2O3, and hydrophobically treated products of these are 0.05 to 10% by weight based on the total amount of toner.
It is preferable to add it within the following range.

The softening point of the magnetic toner according to the present invention is set in order to save thermal energy during fixing and to prevent a rise in temperature inside the copying machine.
17 for reasons such as preventing mutual toner agglomeration.
0°C or lower, preferably 80°C or higher, especially 140°C
The temperature below is preferably 100°C or higher.

The magnetic toner according to the present invention can be easily produced by a conventionally known method. For example, a method of kneading with a hot roll, a heated kneader, or a heated co-kneader, followed by cooling, pulverization, and classification; a method of dissolving, dispersing, or suspending in an appropriate solvent and then spray-drying; It can be obtained by a polycondensation method (for example, interfacial polycondensation, suspension polycondensation, emulsion polycondensation or solution polycondensation). It can also be obtained by appropriately combining the above methods.

The particle size of the magnetic toner according to the present invention is 1 to 50 μm, particularly 7 μm.
~30μ is preferably used. Toner with a particle size of less than 1μ tends to cause toner filming on the image forming member, which can cause stains on the transfer paper, and toner with a particle size of more than 1μ tends to cause poor image quality. Undesirable.

Next, specific examples of the present invention will be described together with comparative examples.

Example-1 Styrene-acrylic resin 40 parts (parts by weight are shown below), magnetic powder (trade name BL-100 manufactured by Titanium Kogyo Co., Ltd.) 6
0 parts, carbon black (product name Conductex 9
75, manufactured by Columbia Carbon Co., Ltd.) 5 parts, charge control agent 2 parts, and low softening point polyolefin (trade name Viscole 6)
60-P (manufactured by Sanyo Chemical Co., Ltd., softening point: 130°C) were thoroughly mixed and kneaded at 170 to 190°C using a heated roll. After cooling, it was crushed and classified by a conventional method to obtain a magnetic toner according to the present invention having an average particle size of 13 μm.

The toner has a softening point of 140°C, a softening start point of 125°C, and an electrical conductivity of 6. I×10”U/cm.

Example 2 The same magnetic toner as used in Example 1 except the low softening point polyolefin was kneaded, classified, and pulverized in the same manner to obtain a magnetic toner having an average particle size of 13.5 μm. The magnetic toner had a softening point of 141 DEG C., a softening start point of 128 DEG C., and an electrical conductivity of 5.5.times.10-15 U/min.

Example-3 40 parts of styrene-acrylic resin, magnetic material (trade name RB
-BL, oil absorption 22m)/10 (1, Kabe; Product name B
L-200, oil absorption: 2 Bml/100 g, 1 part of Glossin-based charge control agent), and 3 parts of low softening point polyolefin were thoroughly mixed and then heated and kneaded.

After cooling, it was crushed and classified to obtain a magnetic toner according to the present invention having an average particle size of 13 μm.

The softening point of this toner is 135°C, and the softening starting point is 115°C.
Met. By using two or more magnetic materials with different oil absorption amounts, it was possible to increase the difference between the softening point and the softening start point of the magnetic toner.

Comparative Example-1 A comparative magnetic toner with an average particle size of 12.5 μm was obtained by using 10 parts of carbon black in the same magnetic toner as used in Example-1 and kneading, crushing, and classifying in the same manner. .

The toner has a softening point of 145°C and a softening starting point of 130°C.
and the conductivity was 4.3 x 1.0'' U/cm.

A running test was conducted using the apparatus shown in FIG. 1 using the toner according to the present invention and the comparative magnetic toner, and the results shown in Table 1 below regarding image quality and fringe were obtained. The photoreceptor 1 was made of selenium, and the intermediate transfer member 5 was an endless belt made of a polyimide base coated with silicone rubber. Roll 7 was set at 160°C, and roll 9 was set at 140°C.

Table-1 Comparative Example-2 40 parts of polyester resin, magnetic powder (trade name BL-100
, manufactured by Titan Kogyo Co., Ltd.), 10 parts of carbon black (trade name: Conductex 9.75, manufactured by Columbia Carbon Co., Ltd.), and 3 parts of low softening point polyolefin (trade name: Viscol 660-P, manufactured by Sanyo Chemical Co., Ltd.). The mixture was mixed, pulverized, and classified to obtain a magnetic toner having an average particle size of 13 μm. The toner has a softening point of 130°C and a conductivity of 3.6X.
10=U/tooth.

Copy Rf of Figure 1: Using a selenium photoreceptor, 2 to 60
Applying a uniform charge of 0 V, solid black development (RH60%
Table 2 below shows the surface reflection densities of the peta black toner images when subjected to the following tests. When using the toner according to the present invention, the reflection density is high and the conductive toner (Comparative Example-2
), a much higher density image can be obtained.

BRIEF DESCRIPTION OF THE DRAWINGS FIGS. 1 and 2 are schematic sectional views showing an example of a recording device using the toner of the present invention. In addition, in the symbols shown in the drawings, 1...
. . . Photosensitive drum 3 . . . Development section 5 . . . Intermediate transfer belt 7 . . . Heating roll 7A, 9A% 25A.・Four heaters 9... Press roll 13... Static elimination member 5... Intermediate transfer roll A,...・Press transfer area B...Intermediate transfer body heating area C...
...Transfer fixing area D... Transfer material heating area T... Toner image P... Transfer material. Agent Patent Attorney Hiroshi Aisaka Figure 1 473 Figure 2

Claims (1)

[Claims] 1. Forming a latent image on an image carrier and developing this latent image with an insulating magnetic toner to form a visible toner image;
A recording method characterized by transferring this toner image onto an intermediate transfer member, and further transferring this transferred toner image onto a transfer material. 2. The method according to claim 1, wherein an insulating magnetic toner having an electrical conductivity of 1.0-130/cIrt or less is used for development. 3. The method described in claim 1 or 2, wherein an insulating magnetic toner having a difference between a softening point and a softening starting point of 5° C. or more is used for development. 4. The method described in any one of claims 1 to 3, wherein an insulating magnetic toner containing a polyolefin having a softening point of 80 to 180° C. is used for development.