JPS5931702B2 - dry printing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention utilizes an electrostatic latent image formed on a sheet-like recording medium that is a mirror image of the original image, using a microscopic microscope containing a heat-sublimable dye and having special magnetic properties. Dry printing in which a printing master is created by developing the powder with a magnetic brush, and is layered on a printing surface that has an affinity for dye vapor, such as polyester cloth, by heating at least a fine developing powder to a predetermined temperature or higher. Regarding the law.

The surface of the electrostatic latent image corresponding to the original image is transformed into an electrostatic latent image by sufficiently mixing non-magnetic particles called toner made of heat-sublimable dye and particles mainly composed of another resin called carrier. Using a developer triboelectrically charged to the opposite polarity, it is developed using a magnetic brush method, cascade method, etc., transferred to a transfer material such as paper, and fixed to create a dyeing master, and then applied to polyester cloth, etc. A dry printing method in which dyeing is carried out by heating and dyeing in layers has been proposed, for example, in Japanese Patent Application Laid-Open No. 48-41085.

However, in the heat dyeing method using a two-component developer as described above, only the dye-containing toner is consumed, so the toner concentration in the developer changes, which in turn appears as a change in the density of the printed color, so it is important to control the toner concentration. In addition, the device became complicated and large in size, and there were many difficulties in perfectly controlling the toner concentration.

Incidentally, in recent years, a developing method using a one-component developer that does not use a carrier, in which the toner itself has magnetism and is used as a magnetic toner, has been developed and is already being put into practical use in electronic copying machines.

For example, in US Pat. No. 3,639,245, D. C
The volume resistance in the electric field of lOOV/CTIL is 104~
A conductive magnetic toner having a resistance of 1011 ohms is disclosed. Further, U.S. Pat. No. 3,909,258 describes a developing method using such conductive magnetic toner, which is held on a conductive sleeve having a magnetic attraction force generating means therein, and is applied to the sleeve through the conductive magnetic toner. A method has been proposed in which a conductive path is formed between the photoreceptor and the back surface of the photoreceptor. Also, in Japanese Patent Application Laid-Open No. 495035, 1012Ω・? A developing method using a conductive magnetic toner having a volume resistivity of preferably 10@2 to 10@6 .OMEGA. and carrying carbon black on its surface has been proposed. However, the above-mentioned developing method using the magnetic toner has the following problems.

First, in the method described in US Pat. No. 3,909,258, it is necessary to always form a conductive path, which complicates the device and also tends to cause fogging.

Furthermore, in the method described in JP-A-50-5035, a conductive toner with relatively low resistance is used, but no special consideration is given to the toner carrier, and good development is not achieved. cannot be expected.

Then, the above magnetic toner is impregnated with a sublimable dye,
Using this magnetic toner, an electrostatic latent image is formed and fixed as necessary to create a master, and this master is placed on an image-receiving sheet that has an affinity for dye vapor and heated to a temperature higher than the sublimation or evaporation temperature of the dye. The dyeing method that becomes
It has been proposed in No. 37, etc. However, the staining method using magnetic toner solves the problem of controlling the toner concentration, but when developing an electrostatic latent image like the two-component developer described above, there are many problems and it is difficult to achieve good staining. I can't.

For example, the method described in JP-A-50-107937 does not mention the electrical or magnetic properties of magnetic toner, and no special consideration has been given to the toner carrier. It is difficult to perform good development.

Since this publication describes the use of an electrodetecting resin as the toner resin, it is thought that development is performed using a mechanism similar to that of conventional two-component developers. JP-A-53-5634 also describes a developing method using a conductive magnetic toner containing a sublimable dye.

With this method, the volume electrical resistance is 102Ω・? Although the following magnetic toner is used and the toner is held on an insulating surface, the resistance of the toner is extremely low, making it extremely difficult to manufacture the toner. Furthermore, since the insulating surface is completely suspended in the air, there is a problem in that charges of the same polarity as the latent image generated by friction between the toner and the insulating surface accumulate on the insulating surface, inhibiting development. In addition, magnetic toners containing sublimable dyes include those in which magnetic particles are coated with a polymer by a spray drying method, as seen in JP-A No. 50-87652, and those in which magnetic particles are coated with a polymer by a spray-drying method, as seen in JP-A-52-63221. For example, resins using a mixture of a polymer having an affinity for dyes and a plasticizer or wax are known.

However, with conventional magnetic toners, no special consideration has been given to their electrical and magnetic properties, making it impossible to achieve good development.

However, the force acting on the magnetic toner during development, that is, the adsorption force on the electrostatic latent image surface, depends on the balance between the force acting on the static image surface and the magnetic force in the opposite direction due to the electrical properties of the magnetic toner and the magnet roll. The magnetic properties and electrical properties of magnetic toner are extremely important in terms of toner properties.
The electrostatic force and magnetic attraction force are intricately intertwined with the toner characteristics, the magnetic force of the magnet roll, the potential of the electrostatic latent image, etc., and it is necessary to fully consider the relationship between these development conditions and toner characteristics. . An object of the present invention is to eliminate the above-mentioned drawbacks of the prior art, and to provide a dry printing method that allows good development using magnetic toner, yields high-quality master paper, and efficiently produces clear color prints. It is to be.

In the dry printing method of the present invention, an electrostatic latent image on a sheet-like recording medium that is a mirror image of the original image is developed with a magnetic brush using a conductive magnetic toner containing a dye that sublimes or evaporates at 70 to 260°C. In a dry printing method in which a dyed master paper is prepared, brought into contact with an image-receiving surface having an affinity for dye vapor, and then heated, (1) as the conductive magnetic toner, conductive particles are formed inside and/or on the surface of the toner particles; By adding particles, the volume electrical resistance can be increased to 102-104Ω.
・Adjusted to a certain range, with a saturation magnetization of 700 to 2000
Contains 30-70% by weight of ferromagnetic particles such that the magnetic properties are Gaussian and have a coercive force in the range of 50-400 oersteds, and 5-30% by weight of a dye that sublimes or evaporates in the temperature range of 70-260°C. Contains 1 polymer
Containing 0 to 50% by weight, average particle size of 5 to 100 μm
Using pressure fixable magnetic toner particles in the range of (
2) The surface of the conductive magnetic toner is at least 10
9Ω? An insulating non-magnetic sleeve with a surface resistance of The electrostatic latent image surface of the sheet-like recording medium is rubbed with the magnetic brush by being adsorbed and conveyed to the non-magnetic sleeve by rotating the sheet-like recording medium, mainly due to the electrostatic latent image electric field. The magnetic toner is made to adhere to the electrostatic latent image surface by the induced electrostatic force such as polarization force, and is visualized. A master having a toner image corresponding to the mirror image of the original image is created by passing it between pressure rolls and fixing it only by pressure, and (4) fixing the master with a different color after dyeing on another support as necessary. (5) place the master on an image-receiving surface that has an affinity for dye vapor and heat the entire master, or only the back surface of the master or the image forming portion of the master to a predetermined temperature or higher under appropriate pressure; One-color or multi-color printing is performed by repeating each of the steps (1) to (5) above as necessary.

The details of the present invention will be explained below with reference to the drawings.

The figure is a diagram for explaining the development and fixing steps in the printing method of the present invention. First, in order to create a master, a sheet-like recording medium 1 is prepared, and the surface of the sheet-like recording medium 1 is uniformly charged and exposed to light. (indicated by symbol). Next, the electrostatic latent image 2 is developed by the developing device 3. The developing device 3 is provided with a non-magnetic sleeve 5 at the bottom of the toner tank 4, and inside the sleeve there are a plurality of magnetic poles (N, S in the figure) extending in the axial direction.
The structure is such that a permanent magnet 6 equipped with a permanent magnet 6 (indicated by ) is arranged. Sleeve 5 and permanent magnet 6 are rotated relative to each other, for example, as shown in the figure, sleeve 5 is rotated in the direction of the arrow in the figure, magnetic toner 7 is pulled out from toner tank 4, and is attracted and conveyed on the sleeve to form magnetic brush 8. Then, development is performed by rubbing the electrostatic latent image surface with the magnetic brush 8. In order to perform good development in the above development process, the characteristics of magnetic toner,
It is necessary to specify conditions that affect development, such as the configuration of the nonmagnetic sleeve and permanent magnet, and the inventors of the present invention have found the following conditions after various studies.

First of all, ordinary magnetic toner is mainly composed of resin and magnetic powder, but in addition to these, conductive particles can be added, for example, inside the toner particles and/or fixed to the surface of the toner particles, thereby increasing the volumetric electricity of the toner. Resistance 102~104
Ω・? At the same time, it is necessary to carry out development while holding the magnetic toner on an insulating surface.

If magnetic toner is held on an insulating surface, a charge of opposite polarity to the latent image charge will be induced in the magnetic toner in the electrostatic latent image electric field, and a polarization force etc. will be generated between this charge and the latent image charge. Development can be carried out using electrostatic force. The inventors prepared magnetic toners with various resistances and conducted copy tests under three different conditions.
The results shown in Table and Table 2 were obtained.

The magnetic toner used was Mitsui Chemical's Hiwax 200P1 as a resin and Toda Kogyo's EPT as magnetite.
Mitsubishi Kasei +40 as 5OO and carbon black
and prepared as described below using oxinophthalone as a sublimable dye. Then, development and fixing were performed using a commercially available CPC copying machine under the conditions shown in Example 1 below to obtain a copy image. However, an aluminum sleeve was used as the conductive sleeve, and an aluminum sleeve coated with a mylar film was used as the insulating sleeve. First, as is clear from Table 1, when an insulating sleeve is used and the resistance of the toner is 102Ω or more, a good image without background smudge can be obtained under all conditions.

On the other hand, if the resistance of the toner is high, low-humidity fogging will occur, and good images will not be obtained at high temperatures and high humidity, so the resistance of the toner is 104Ω・? It is necessary to do the following. Then the second
As is clear from the table, the same tendency as in Table 1 can be seen even when a conductive sleeve is used, but in order to obtain good images under all conditions, the resistance must be kept within a narrow range of 103 to 104 Ω. Since it is necessary, we will take practicality into consideration, taking into account the manufacturing variations of toner.

Also, if the resistance of the toner is in the range of 104 to 109 Ω・I, the toner resistance is greatly affected by the amount of carbon black added, but if it is in the range of 102 to 10” Ω・I, the amount of carbon black added has little effect. Therefore, from the viewpoint of manufacturing the toner, the resistance is preferably in the range of 102 to 104 Ω.

In order to make the surface of the toner carrier insulating in the above, for example, the surface of a conductive sleeve made of aluminum or stainless steel is coated with Mylar film, the surface of an aluminum sleeve is treated with alumite, or an insulating material such as plastic is used. However, it is necessary that the sleeve has a surface resistance of at least 10Ω·α or more.

This is because if the resistance of the insulating surface is less than 10 Ω/solder, it will no longer function as an insulator. In order to perform good development, it is necessary that the magnetic force of the permanent magnet shown at 6 in the figure be in the range of 500 to 1200 Gauss on the non-magnetic sleeve.

This is because if the magnetic force is less than 500 gauss, the toner conveying force will be weakened and the toner will tend to clump on the sleeve.On the other hand, if it is more than 1200 gauss, the magnetic attraction force will be larger than the electrostatic attraction force. If too much toner adheres, the amount of toner adhesion decreases and sufficient development becomes impossible. Furthermore, if the number of magnetic poles of the permanent magnet is less than 4, toner cannot be sufficiently transported, and especially when the magnet rotates, stripes in the pitch between the magnetic poles due to the alternating magnetic field become noticeable, making it impossible to obtain a clear image.

In particular, when a one-piece cylindrical magnet is used as a permanent magnet, there is no axial joint compared to when block-shaped magnets or ring-shaped magnets are used, which improves the uniformity of magnetic force in the axial direction and prevents uneven development. There are advantages such as being able to

Furthermore, in addition to resistance, the magnetic toner used in the present invention must also have magnetic properties within the following range.

That is, it is necessary that the saturation magnetization amount is 700 to 2000 Gauss and the coercive force is 50 to 400 Oersteds. This is because when the saturation magnetization amount is less than 700 Gauss, the toner becomes a magnetically soft material, so each particle acts independently and tends to aggregate on the magnet roll, that is, it tends to cause blocking. If it exceeds Gauss, the magnetic attraction force will be too strong and developability will deteriorate. However, it is more preferable for the saturation magnetization amount to be large within this range because the toner particles come together to form a magnetic brush, so that toner scattering is extremely reduced and the toner conveying force is increased. Next, if the coercive force is less than 50 oersted, the force of conveying the toner on the magnet roll will be small, making it difficult to replenish the toner uniformly and causing a large amount of toner to scatter. Since the toner tends to move freely, the toner tends to adhere to the non-charged portion of the electrostatic latent image surface, that is, fog becomes large. If the coercive force exceeds 400 oersteds, the toner tends to attract each other and coagulate, and the toner conveying force is too strong, causing the toner to be strongly compressed at the part that regulates the thickness of the toner conveyed on the magnetic roll. Problems such as protrusion and deterioration occur. Note that in order to obtain the above magnetic properties, the amount of magnetic powder in the toner needs to be 30% by weight or more, but if the amount of magnetic powder is too large, the fixing properties will be poor, so it needs to be 70% by weight or less. .

Magnetic powders that can be used in the present invention include magnetite, ferrite, barium ferrite, strontium ferrite, and various metal powders, with magnetite being commonly used. These magnetic powders may be used alone or in combination of two or more. Further, as the toner resin, it is necessary to use the following polymer in order to enable pressure fixing.

That is, in order to improve the pressure fixing property, the molecular weight is 500.
~10,000 natural or synthetic waxes, e.g.
Beeswax, paraffin wax, microcrystalline wax, hydrogenated wax, carbana wax, halogenated paraffin, polyethylene wax, etc. can be used. It is necessary to include these polymers in the toner in an amount of 10% by weight or more from the viewpoint of pressure fixability, but if it exceeds 50% by weight, it is not preferable because the content of magnetic powder and dye must be reduced.

In the present invention, the dye to be contained in the toner is 70 to 260% of various dyes such as basic dyes and disperse dyes.
It is necessary to use a material that sublimes or evaporates at ℃.

This is because if the sublimation temperature of the dye is too low, the storage stability will be poor, while if the sublimation temperature is too high, the subsequent heating dyeing step will be difficult. Examples of such dyes include 1-
Examples include amino-hydroxy-anthraquinone, hydroxyquinophthalone, 1-amino-2-phenoxy-4-hydroxy-anthraquinone, and the like. One or more of these dyes may be contained in the toner particles, and the content is preferably in the range of 5 to 30% by weight. If it is less than 5% by weight, sufficient dye vapor cannot be generated during heat dyeing, and if it exceeds 30% by weight, the amounts of other components, such as polymers and magnetic powder, will not be sufficient. The magnetic toner used in the present invention is prepared as follows.

First, resin, magnetic powder, dye, and if necessary, conductive particles are premixed and then heated and kneaded using a seconder or the like. Next, the kneaded material is cooled and solidified, then pulverized using a dinit mill, etc., and after spheroidizing, it is classified to have an average particle size of 5 to 100 μm, preferably 10 μm.
The particles are ~40 μm. If the average particle size of the toner is less than 5 μm, it will be consumed preferentially during development and will easily cause fogging.
If the average particle size exceeds 100 μm, it will be difficult to develop. When adhering conductive particles to the surface of toner particles, conductive particles can be added to the pulverized powder, mixed, mixed in a hot air stream, and sent to a spheroidizing furnace, or in a mixer under the action of centrifugal force. Mixing and agitation may also be used. The above-mentioned magnetic toner is developed with a magnetic brush using a magnet roll having an insulating sleeve, and the resulting developed image is fixed under pressure to complete a master.

Although thermal fixing may be used to fix the developed image, since the magnetic toner contains a thermally unstable dye, it is advantageous to use pressure fixing, which allows fixing at room temperature. As shown in the figure, an upper roll 10 of a pressure fixing device 9 is formed by rotatably incorporating an upper roll 10, a middle roll 11, and a lower roll 12.
This is done by passing the recording medium 1 between the pressure roll and the middle roll 11. In order to achieve good fixing, the compressive stress generated in the contact area of the pressure roll must be 500k9/Cd or more. If the stress is too high, paper wrinkles tend to occur and it is also undesirable from the viewpoint of the strength of the fixing device.
000k9/Cr! It is necessary not to exceed i. The image surface of the master obtained as described above is overlapped with an image receiving surface that has an affinity for dye vapor, and the entire area is heated under a predetermined pressure, or the master is heated from the back side, or only the image forming area is heated. Dyeing is performed by selectively heating the dye to a temperature higher than a predetermined temperature, for example, higher than the vaporization temperature of the dye.

In this case, the image receiving surface is preferably a cloth containing 50% or more polyester, but is not limited to this, and may be synthetic paper having a layer containing 50% or more polyester.

Example 1 A master was created as follows using a commercially available CPC copying machine.

The surface of an A4 size zinc oxide paper was uniformly charged to 300 V and exposed to light to form an electrostatic latent image that was a mirror image of the original image, and then developed. At this time, the outer diameter is 3 as sleep.
A 2m TIL aluminum cylinder coated with Mylar film is used as a permanent magnet, and the outer diameter of the sleeve is 8 poles symmetrically magnetized with a magnetic force of 800 Gauss.
m cylindrical barium ferrite magnet, the sleeve was heated to 200 rpm. p. m. The toner thickness on the sleeve was set to 0.5 mu, and the gap between the sleeve and the zinc oxide paper was set to 0.8 mm. The magnetic toner used was 25 parts by weight of polymer (microcrystalline wax), 60 parts by weight of magnetite (EPT5OO manufactured by Toda Industries), 5 parts by weight of carbon black (+44 manufactured by Mitsubishi Kasei), and 10 parts by weight of dye (oxinophthalone). The powder obtained by premixing, heating kneading, cooling solidification, pulverization, and spheroidization was mixed with 1% by weight of carbon plaque, sent to a spheroidization furnace, fixed the carbon, and then classified to obtain a powder with an average particle size of 30 μm. Toner was used.

The resistance of the toner is D. ClOO/(V7!~D.C4OO
Approximately 5×102Ω・? in the OV/CTn electric field. The saturation magnetic flux density was 1100 Gauss, and the coercive force was 250 Oersted. Upper roll after development (outer diameter 32mm),
Equipped with a middle roll (outer diameter 20mm) and a lower roll (outer diameter 32mm), the compressive stress between the upper roll and the middle roll is 3000.
Using a pressure fixing machine with a pressure of kg/Cd, a master was created by passing zinc oxide paper between upper and lower rolls for pressure fixing.

Under load 2 with this master layered on polyester cloth
A clear print was obtained when heated at 00'CXlOsec.

Example 2 A master was created as follows using a commercially available facsimile machine.

An electrostatic latent image that was a mirror image of the original image was formed on the surface of electrostatic recording paper using a pin electrode, and then developed. At this time, the same sleeve and permanent magnet as in Example 1 were used, and the sleeve was heated to 350 rpm. p. m. The toner thickness on the sleeve was set to 0.6 mm, and the development gap was set to 0.6 mm.
It was set to 9mm. The magnetic toner used was 20 parts by weight of polymer (paraffin wax), 60 parts by weight of magnetite (EPT5OO manufactured by Toda Industries), 3 parts by weight of carpon plug (+44 manufactured by Mitsubishi Kasei), and dye (1-amino-2-phenoxylene). A powder obtained by adding 17 parts by weight of sea anthraquinone in the same manner as in Example 1 was added to 0.8 parts by weight of carbon black.
A toner having an average particle diameter of 25 μm obtained by mixing the above particles and kneading with a mixer to fix the carbon and classifying the carbon was used.

The resistance of the toner is D. CLOOV/CTrL-D. ClO
Approximately 8X103Ω・? in an electric field of OOV/(177!)
The saturation magnetization is 1200 Gauss, and the coercive force is 200.
It was Elsted. After development, pressure fixing was performed using the same pressure fixing machine as in Example 1 to produce a master.

When this master paper was layered on a polyester cloth and heated at 190° C. for 10 seconds by applying pressure, a clear print was obtained.

As described above, according to the present invention, clear dyeing without color unevenness or staining can be easily performed.

[Brief explanation of the drawing]

The figure is a diagram for explaining the development and fixing steps in the present invention. 1: Recording body, 2: Electrostatic latent image, 5: Nonmagnetic sleeve, 6:
Permanent magnet, 7,7': Pressure roll.

Claims (1)

[Claims] 1. A non-magnetic recording medium that forms an electrostatic latent image that is a mirror image of the original image on the surface of a sheet-like recording medium, and a permanent magnet having a plurality of magnetic poles extending in the axial direction is arranged inside. On the sleeve, 7
5-30% of dyes that sublimate or evaporate at temperatures of 0-260℃
% by weight, containing 30-70% by weight of ferromagnetic particles and 10-50% by weight of polymer, and containing conductive particles inside and/or on the surface of the toner particles, with an average particle size of 5-70% by weight.
A 40 μm conductive magnetic toner is supplied, a magnetic brush is formed by relative rotation of the permanent magnet and the non-magnetic sleeve, and a magnetic toner image is formed by rubbing the surface of the recording medium with the magnetic brush. Create a stain master by
Bringing the surface of the dyeing master holding the magnetic toner image into close contact with an image receiving surface having an affinity for the dye vapor;
In the dry printing method in which the dye is heated above its sublimation or evaporation temperature, (1) as the conductive magnetic toner, 1
It has a volume electrical resistance of 0^2 to 10^4 Ω・cm and 7
(2) As the non-magnetic sleeve, at least the surface thereof is 10^9 Ω cm or more; An insulating sleeve having resistance is used, and the magnetic force on the non-magnetic sleeve is mainly induced by the electric field of the electrostatic latent image, using a permanent magnet in the range of 500 to 1200 Gauss as the permanent magnet. The magnetic toner is attached to the electrostatic latent image by electrostatic force such as polarization force to form a magnetic toner image, and (3) the recording body holding the magnetic toner image is subjected to a compressive stress of 500 to 6000 kg/cm^2. A dry printing method characterized in that the master is created by passing the master between a pair of pressure rolls having a pressure roll and fixing it only by pressure. 2. The dry printing method according to claim 1, characterized in that a cloth containing 50% or more polyester is used as the image receiving surface. 3. The dry printing method according to claim 1, wherein a zinc oxide photosensitive paper is used as the sheet-like recording material, and an electrostatic latent image is formed on the surface thereof by an electrophotographic method. 4. The dry printing method according to claim 1, wherein an electrostatic recording paper is used as the sheet-like recording material, and an electrostatic latent image is formed on the surface thereof by an electrostatic recording method.