JPH049961A - Toner for developing electrostatic charge image and recorder - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a toner for developing electrostatic images in electrophotography, electrostatic recording, and the like.

The present invention also relates to a recording device such as an electrophotographic method.

BACKGROUND ART Conventionally, electrophotography and electrostatic recording have been well known as recording methods that utilize colored powder. These methods (
This is a plate on which an electrostatic latent image is formed on a charge-retaining material such as an electrophotographic photoreceptor or a dielectric material, and then developed with a colored powder (toner) charged to the opposite polarity to that of the latent image to obtain a toner image. The final recorded material is obtained by transferring the image onto an image receptor and further fixing it.

As a toner for developing electrostatic images, it is widely known that particles obtained by dispersing colored powder such as carbon black or dye in a binder resin such as polystyrene resin and pulverized to 10 to 20 μm are used. . However, when such toner is fixed and recorded on paper, which is an image receptor, and the recorded paper is to be recycled and reused as paper, it is very difficult to process it.

When recycling recorded paper collected as waste paper
First, it is put into a mixer called a ``helper'' with water, and the pulp fibers are loosened in the water.

After that, impurities such as ink are separated using a floatator, followed by decolorization and bleaching. The paper is then turned into recycled paper by a paper machine. Ingredients to be bleached in the bleaching process
Most toners (like those mentioned above) are made of a polymeric binder and pigment, and at present, decolorization is carried out by mixing detergent and raising the temperature (de, stirring, etc.). Thermoplastic resins are commonly used as binder resins, and styrene resins are
Acrylic resins, polyester resins, etc. are used (these materials are not easily soluble in solvents, and therefore decolorization is extremely difficult).

In addition, in conventional recording apparatuses, the method of electrostatically transferring a powder image formed on an image carrier onto an image receptor using a corona charger or the like, and then thermally fixing it using a heated roller is widely used. However, this method had various problems, specifically (a) in the electrostatic transfer step (t.

(1) There is scattering of toner called scattering, which blurs the recorded image.

(2) Transfer efficiency decreases in a high temperature environment.

(3) Transfer becomes unstable due to fluctuations in resistance between toner and image receptor.

(b) In the heat fixing process, (1) power consumption used as thermal energy is large and uneconomical;

(2) It takes a long time to warm up until the temperature of the fixing unit rises when the power is turned on. (3) Because of the high temperature, there is a risk of fire when paper jams, etc.

Among these problems, in order to solve the problems related to heat fixing, a method of dissolving and reducing the viscosity of a toner image with a solvent and transferring it to an image receptor was disclosed. has been disclosed. This method is shown below.

First, a toner image is formed on a photoreceptor drum by a normal electrophotographic process. Next, a toner particle dissolving drum (hereinafter referred to as dissolving drum) coated with a solvent capable of dissolving toner is placed opposite to the photoreceptor drum with a gap therebetween. Then, the toner image on the photosensitive drum is electrostatically transferred to the melting drum by a transfer charger disposed inside the melting drum.

The toner transferred to the melting drum is dissolved and made viscous by a solvent. In this state, if the paper is brought into close contact with the toner image, the problem that occurs when the toner image is adhesively transferred to the paper due to the adhesive force of the viscous toner is not solved. When the toner is melted and reduced in viscosity on the drum, the viscosity of the toner is reduced from the side in contact with the melting drum, resulting in a large amount of toner adhering to the melting drum, resulting in low transfer efficiency to the paper. j, :.

In view of this, an object of the present invention is to provide a toner for developing electrostatic images that can be easily decolorized and recycled after recording on paper, which is an image receptor.

Furthermore, the present invention has a simple device configuration, is capable of transferring toner images with low energy and fixing at room temperature, and (2) provides a recording device that can obtain clear images with good transfer efficiency. Means for Solving the Problems of the Invention A toner for developing electrostatic images containing at least a binder and a coloring agent, wherein at least a part of the composition of the binder is melted in water to reduce the viscosity. In addition, at least a portion of the composition of the binder, which contains at least a binder and a colorant, has a higher solubility in alcohol or a mixed solvent of water and alcohol than in water. The toner for developing an electrostatic image is characterized by: an image forming means for forming the toner image on an image carrier, the toner image being made of a toner for developing an electrostatic image whose viscosity is reduced by a mixed solvent of water and alcohol; The recording apparatus is characterized in that it is equipped with a solvent supply means for supplying the toner image with the toner image, and a transfer means for pressing and transferring the toner image whose viscosity has been reduced by the solvent onto the image receptor.

Effects of the present invention 41 With the above configuration, the following deceptive effects can be obtained. Akira Sunawa - For boat fishing As a toner for developing electrostatic images (Yo) Particles made by dispersing colored powders such as carbon black, dyes, and various additives in a binder and pulverizing them into particles of 10 to 20 μm. (In the present invention, a water-soluble resin is used as the binder. When recycling recorded paper recorded with this toner, first use force to remove the pulp fibers of the recorded paper in water.) Bleaching (
Toner that should be deinked (deinking)
During the process of loosening the pulp in water, the binder is dispersed into the water along with the pigment. Removal of impurities, decolorization
Bleaching process is almost unnecessary, improving deinking rate L
Recorded paper can be recycled and reused very easily. Also, if a material with higher solubility in alcohol or a mixed solvent of water and alcohol than in water is used as a binder for l-ner, the above-mentioned recycled paper recycling process The decolorization process is more efficient when carried out with alcohol or a water/alcohol mixed solvent than with water.However, the process is much easier than conventional methods.

In other words, alcohol has low danger as an organic solvent, and ethyl alcohol is not particularly toxic, so there are no restrictions on its use, and there are no problems with its use in the treatment process. For example, by making the adhesive less soluble in water or using a material that is completely insoluble,
The toner absorbs moisture from the air and becomes viscous, reducing the toner's fluidity and changing its recording characteristics.Also, even if the recorded image is exposed to water, the image will not run out. , the image has excellent water resistance.

Furthermore, by using an image bearing member, toner, and a solvent that can reduce the viscosity of the toner, a toner image is formed on the image bearing member by an image forming means, and the viscosity of the toner image is lowered with the solvent, thereby transferring the toner image. and room-temperature fixing at the same time.This solves various problems in each process of electrostatic transfer and heat fixing using a heat roller.It has a simple device structure and is low-energy, recording that produces clear images with good transfer efficiency. Realize the device.

Considering safety, cost, etc., it is conceivable to use water as the solvent. However, this solvent has the ability to soak into paper, which is an image receptor, during transfer and fixing. When comparing alcohol or a mixed solvent of water and alcohol as a solvent, it is easier to dry after it soaks into the paper, and it dries more easily. Wrinkles in paper: No curls - Water stretches paper fibers and causes wrinkles, but this can be alleviated by mixing alcohol. Also, when mixed with alcohol, it easily penetrates into the paper, eliminating the difference in expansion and contraction between the front and back sides of the paper, and preventing curling.

In addition, a mixed solvent (unlike clean water, it does not weaken the stiffness of the paper, so it does not interfere with the running of the paper in the recording device).
In addition, a mixed solvent of water and ethyl alcohol (a mixed solvent of water and ethyl alcohol) is allowed to be used freely under the Fire Service Act and the Labor Safety Act.Also, a mixed solvent of water and alcohol is cheaper than alcohol. By using a mixed solvent of water and alcohol as a solvent, it is possible to achieve transfer fixing with excellent safety, price, print quality, and print stability.

Example Examples of the toner of the present invention will be described below.

For example, a water-soluble polymer is used as the binder for the toner.

It is desirable to use 20 to 80% by weight based on the total amount of toner. Water-soluble polymers include polyvinyl alcohol (PVA), carboxymethyl cellulose (CMC), polyethylene glycol (PEG), polypropylene glycol (PPG), methylcellulose, alginic acid, polyacrylic acid, polyethylene oxide, and starch.
Examples include gelatin. Among these, there are thermoplastic materials (PEG, PPG, etc.). PEG is also soluble in a mixed solvent of water and ethyl alcohol.
/PPG copolymer. Ethyl cellulose is an example of a resin that dissolves in alcohol but is insoluble in water.

Additives such as a coloring agent and a fluidity improver can be used in the toner of the present invention, if necessary.

As the coloring agent, known suitable pigments or dyes are used. It is desirable to use 1 to 20% by weight based on the total amount of toner.

Fluidity improvers include 5IO2, TlO2, Al2O3
and their derivatives etc. are 0.05% of the total amount of toner.
It is preferably used in a range of 1.0% to 10% by weight. Also, in connection with the toner manufacturing method, a suspension stabilizer or the like may be added.

When the toner of the present invention is used as a magnetic toner, commonly used magnetic powders are mixed with the toner. It is a fine powder of metal compounds containing ferrite, ferromagnetic ferrite, and mixtures thereof, and the blending amount is preferably 10 to 80% by weight, preferably 35 to 65% by weight based on the total amount of toner. Is it necessary to mix a mold release agent to prevent offset?

Further, when the toner of the present invention is used as a conductive toner, a highly conductive substance such as carbon black is used as the conductive substance by mixing in an amount of 1 to 30% by weight based on the total amount of the toner.

The toner of the present invention can be obtained by conventionally known methods.For example, toner raw materials are kneaded with hot rolls and then classified using cold paper.The toner raw materials are molten and dispersed or suspended in an appropriate solvent, and then spray-dried. Alternatively, it can be obtained by various polycondensation methods.

The particle size of the toner of the present invention produced by the above method is 5 to 2.
0 μm is preferable - Particles with a small diameter tend to cause toner filming, and therefore tend to cause stains on the image receptor, and larger particles tend to cause poor image quality (- Specific examples of toners are shown below.

Example 1 PEG (Nippon Oil & Fats Co., Ltd., PEG20000)
, PVA (Kuraray Co., Ltd. K PVA215)
When the temperature is increased to 120° C., the mixture rapidly softens.

・Carbon black (Colombian Carbon Japan)
Hyoro Co., Ltd. C0NDUCTE Particles of 5 to 20 .mu.m were obtained.Example 2: A plasticizer was mixed with ethylcellulose (Percules Co., Ltd. 1, ethoxyl content: 48, low viscosity type) to lower the softening point, and when the temperature was raised to 130.degree. C., it softened rapidly.

・Carbon black (Colombian Carbon Nippon Co., Ltd. Kan CONDUCTE Classify the fine powder with a crusher to 5 to 2
Example 3 in which particles of 0 μm were obtained: Alkylene oxide derivative (Daiichi Kogyo Seiyaku 9x PA:
/), a mixture of PVA (PVA21 anti-partially saponified manufactured by Kuraray Co., Ltd.)? ! 1. ．． When the temperature is raised to 120°C, it softens rapidly.

・Carbon black (Colombian Carbon Japan)
C0NDUCTE It was thoroughly classified into fine particles to obtain particles of 5 to 20 μm.

Comparative Example 1° Polystyrene resin When heated to 120°C, it softens rapidly.

・Carbon black (Coconbyan Carbon Japan Co., Ltd.)
After kneading the toner raw materials consisting of Gourd C0NDUCTE
Partially saponified PVA has the ability to dissolve in water, but it also dissolves in a mixed solvent of water and lower alcohol.The lower the mixing ratio of alcohol, the higher the solubility.

PEG2000 (1. Solubility in water It also dissolves in a mixed solvent of water and lower alcohol. The lower the mixing ratio of alcohol, the higher the solubility.

Ethyl cellulose (if the ethoxyl content is about 48%), it is insoluble in water but is well soluble in ethyl alcohol.

Alkylene oxide derivative Li is a PEG/PPG copolymer copolymerized with a ratio of 80% PEG and 20% PPG, and has a molecular weight of about 17,000 and a melting point of about 65°C. PEG/PPG copolymer, human water/
Comparing the solubility when dissolved in three types of solvents: ethyl alcohol = 4/6 and ethyl alcohol at a weight ratio of solute/solvent - 1/2, the solubility in water and ethyl alcohol (higher solubility) is low, and in the case of mixed solvents is high and f
4.The reason for this is that LPEG is water-soluble and PPG is alcohol-soluble.If a mixed solvent is used, water and alcohol will dissolve the copolymers PEG and PPG, respectively.

Solubility here refers to solubility, which is evaluated based on the degree of solubility after a certain period of time when a certain ratio of solute and solvent are mixed at a certain temperature.

The toners of Example 1, Example 2, Example 3, and Comparative Example 1 were developed using a magnetic toner developer, and the toner images were electrostatically transferred to paper as an image receptor. When fixing at room temperature by solvent evaporation in Example 3 and fixing on paper using a fixing device using a heated roller in Comparative Example 1, each toner was excellent when evaluating the fixability of the fixed image by friction fastness.T Island Each toner image Table 1 shows the solvent resistance of

The toner image of Example 1 in Table 1 shows that when the recording paper is dipped in water, the text quickly dissolves and can be easily removed from the image receptor. Toner image of Example 2 (no change even when immersed in water)
When immersed in a mixture of water/ethyl alcohol = 4/6 and ethyl alcohol, the solution appeared. In Example 3 such as 71, the letters were slightly dissolved for the first time after being immersed in water for a long time. Water/ethyl alcohol - 4/6 When the toner image of Comparative Example 1 is dipped in a mixed solution of water, water, ethyl alcohol, and ethyl alcohol, the character portion immediately dissolves. toner (very water resistant)
This is a toner that can be easily decolorized using a water/alcohol mixed solvent.

Examples 1, 2, and 3 show that all of the binder composition is a material that dissolves in the solvent. The higher the ratio, the higher the solubility of the toner, and the above-mentioned effect increases.

FIG. 1 shows a schematic diagram of an embodiment of a recording apparatus using the toner of the present invention.

This embodiment will be explained by taking as an example a case where an ion irradiation head is used as an image forming means for forming a powder image.

S, P, 180218, etc.

In FIG. 1, 1 is an ion irradiation head that irradiates ions in accordance with an image signal, and 2 is a dielectric drum A3, which is an image carrier having a dielectric layer supported on the circumferential surface of a conductive drum such as aluminum. Example 3 above. A developing device 4 which performs development with toner is a toner image formed on the dielectric drum 2.

The ion irradiation head 1 and the developing device 3 constitute an image forming means for forming a toner image 4 on the dielectric drum 2.

5 (a) A solvent for reducing the viscosity of the toner image 4 is supplied onto the dielectric drum 2 in the form of a mist & is used as a solvent supply means. A solvent mist generator is shown.

6 is a pressure roller which is a transfer means and is provided in pressure contact with the dielectric drum, and 9 is a recording paper which is an image receptor.

As recording paper 9 (for example, 64g/m2 PP
Use C paper.

Further, the pressing roller 6 is used to press the toner image 4 whose viscosity has been reduced and the recording paper 9 onto the dielectric drum 2 together with the dielectric drum 2 .

7 (Friend) This is a cleaning unit that cleans untransferred toner remaining on the dielectric drum 2, and cleans the untransferred toner on the dielectric drum 2 with a metal blade.

8 (Dai) This is a static eliminator that erases the electrostatic latent image on the dielectric drum 2.

10 is a solvent tank; 11 is a solvent supply pump; 1
2 is an ultrasonic vibrator, 13 is a blower fan, and 14 is a solvent mist.

In this example, a mixed solvent of water/ethyl alcohol (4/6) was used as the solvent. The operation of the recording apparatus of this embodiment constructed as above will be described below.

First, the ion irradiation head 1 forms an electrostatic latent image according to an image signal.

A toner image 4 is formed on the dielectric drum 2 by contact development by the electrostatic latent image developing device 3 .

On the other hand, the solvent mist generator 5 is connected to a solvent tank 10, and a solvent is supplied to the solvent mist generator 5 by a solvent supply pump 11. The solvent supplied to the solvent mist generator 5 is turned into a solvent mist 14 by one or more ultrasonic transducers 12 provided within the solvent mist generator 5 . Here, the solvent mist 1 is generated by the air flow sent by the ventilation fan 13 provided on the national body of the solvent mist generator 5.
4 force (supplied toward the surface of the dielectric drum 2 to reduce the viscosity of the toner image 4 on the dielectric drum 2).

As described above, the solvent mist generator 5 supplies the solvent mist 14 to the toner image 4 on the dielectric drum 2 .

The portion of the toner image 4, that is, the image area (which has a higher solvent affinity) is in a state where the solvent mist 14 is very likely to adhere to it, that is, it is in a state where it is easily wetted by the solvent.

Once the solvent has adhered to the toner, it permeates and diffuses into the toner and its viscosity decreases, and the state in which the solvent mist 14 on the surface of the toner easily adheres continues.
Toner viscosity continues to decrease. At this time, the amount of α solvent mist 14 supplied (in the case of a solid image, it is approximately several g/m2 or a preferable force (this varies depending on the material of the binder of the toner, etc.).

- For binders with high radiation solubility in solvents (such as
The viscosity can be lowered with a smaller amount of solvent.

Next, in a state where the viscosity of the toner image 4 has been sufficiently reduced by the solvent mist 14, the toner image 4 on the dielectric drum 2 is
is pressed onto the recording paper 9 and at the same time enters into the fibers of the recording paper 9 and is transferred.

The solvent contained in the transferred toner in this state evaporates or permeates and dries, causing it to be fixed.
The final recording is obtained. Finally, the dielectric drum 2 is cleaned by a cleaning unit 7 to remove paper dust and the like remaining on the dielectric drum 2. Thereafter, the static electricity is removed by the static eliminator 8, and the electrostatic latent image is erased.

At this time, since the toner image 4 has a low viscosity due to the solvent, it is clear that the pressure applied to the pressure roller 6 can be suppressed much lower than in conventional devices using pressure fixing, for example. be. The pressure applied to the pressure roller 6 can be reduced from tens of tenths to several hundredths in the conventional pressure fixing method.

Advantages of using water as a solvent＼ Advantages considered from the viewpoint of cost and safety＼ Mixed solvent of water and ethyl alcohol C
t Easier to dry than water after soaking into paper.

Also, there is almost no curl in the paper when it dries.
% In addition, unlike water, it does not weaken the paper, so it does not interfere with the running of the paper in the recording device. Free use is permitted under the Fire Service Act and the Labor Safety Act. Therefore, by using a mixed solvent of water and ethyl alcohol as the solvent, it is possible to achieve excellent printing quality, printing stability, etc. As described above, in this embodiment, the viscosity of the toner image 4 is reduced by the solvent mist 14 by providing the solvent mist generator 5 which is a solvent supply means for supplying a solvent that reduces the viscosity of the toner image 4. By doing so, transfer and fixing can be performed at the same time, so it is possible to realize a printing apparatus that is high-speed, has low power consumption, and has a simple configuration.

In addition, since contact transfer is used, there is no disturbance of the toner image during transfer, and a transfer rate of 90% or more can be easily achieved.Therefore, a clear image with good transfer efficiency can be obtained. A specific example will be described in which a solvent is supplied to the upper toner image when it comes into contact with recording paper.

FIG. 2 shows a schematic diagram of a second embodiment of a recording apparatus using the toner of the present invention.

The device of this embodiment shown in FIG. 2 basically has the same configuration as the device shown in FIG. 1, so the same components are given the same numbers and detailed explanations will be omitted.

In FIG. 2, reference numeral 15 denotes a solvent application roller that applies and supplies the solvent to almost the entire width of the recording paper 9; 16 denotes a solvent supply felt that supplies the solvent to almost the entire width of the solvent application roller 15;
17 is a solvent supply pipe that impregnates almost the entire width of the solvent supply felt 16 with a solvent.

The solvent supply pipe 17 (Table 1) is connected to the solvent tank 10 via the solvent supply pump 11.The solvent supply pipe 17 is provided in close contact with the upper end of the solvent supply felt h16, and a plurality of solvent supply pipes are provided on the side in contact with the solvent supply felt 16. The solvent supplied by the solvent supply pump 11 flows out from these holes, impregnating the solvent supply felt 16 with the solvent.Also, the solvent supply felt 16
is provided so as to be in contact with the solvent application roller 15,
A liquid film of the solvent is formed by coating the surface of the solvent coating roller 15. When the solvent application roller 15 comes into contact with the recording paper 9, the solvent is applied and supplied to the surface of the recording paper 9.

The operation of the printing apparatus of this embodiment configured as described above will be explained below.

A toner image 4 is formed on the dielectric tram 2 by the same steps as in the first embodiment. In parallel with this, a solvent is applied and supplied onto the surface of the recording paper 9 by a solvent application roller 15. In this state, the dielectric drum 2 and the recording paper 9 are pressed together by the pressure roller 6.

At this time, toner image 4 on dielectric drum 2\recording paper 9
By contacting the above solvent, the viscosity of the l·ner image 4 on the recording paper 9 side progresses to become lower. At the same time, pressure is applied to the toner image 4 and the recording paper 9 by the pressure roller 6, and the low-viscosity portion of the toner image 4 is deformed and penetrates into the fibers of the recording paper 9 to be fixed. . In this state, the solvent contained in the transferred toner evaporates or permeates and dries to obtain the final recorded matter.

The force described above is based on the embodiment in which the solvent is supplied to the toner image number on the image carrier when it comes into contact with the recording paper (according to this second embodiment, the solvent is coated and supplied onto the recording paper 9). By providing the solvent coating roller 15 and supplying the solvent to the toner image 4 using the recording paper 9 coated with the solvent, in addition to the effects of the first embodiment of the present invention described above, a simple method can be achieved. Furthermore, as can be seen from examples such as printing machines, it is relatively easy to increase the speed of solvent supply by using a method of coating and supplying with rollers.

A 4/6 mixed solvent of water and ethyl alcohol was used as the solvent, but other ratios may be used, and other alcohols may also be used.However, when using an alcohol other than ethyl alcohol, or when using 60% or more alcohol. (You will need to be careful when using it.

In addition, in these embodiments, the image forming means is not limited to the ion irradiation head, the dielectric drum, or the process using conductive magnetic toner. reflected light
Photoreceptor drum Of course, an electrophotographic process such as insulating or non-magnetic toner may be used.

In addition, in this embodiment, a latent image is formed on the image carrier.
The force explained using the example of developing with toner (
It is not limited to this example, but it is also possible to form a Yotoner image on another photoreceptor drum. The intermediate transfer member corresponds to the image bearing member set forth in claim 3 of the present invention.

As a method of transferring a powder image to such an intermediate transfer body, (
For example, when using an adhesive silicone rubber roller as the intermediate transfer body and transferring the toner image using the viscosity of the rubber on the surface, or when using insulating toner (such as corona transfer), the toner image may be transferred to the intermediate transfer body using a method such as corona transfer. You can use methods such as transcribing.

Furthermore, fixing can be carried out at room temperature by solvent evaporation, but it goes without saying that additional heating means may be provided to increase the evaporation rate.

Furthermore, in this embodiment, materials other than paper may be used, such as HP, which is described in the case where PPC paper is used as the image receptor.

DETAILED DESCRIPTION OF THE INVENTION According to the present invention, there is provided a toner for developing electrostatic charge images that can be easily decolorized and recycled after recording on paper as an image receptor.

Further, the present invention provides a recording device which is capable of transferring and fixing toner images with a simple device configuration and low energy consumption, and which can obtain clear images with good transfer efficiency, and has great practical effects.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of a recording apparatus according to an embodiment of the present invention. FIG. 2 is a schematic diagram of a recording apparatus according to another embodiment of the invention. 1...Ion irradiation head, 2...Dielectric drum
3... Developing device 4... Toner image 5... Solvent mist generator 6... Pressure roller 7... Cleaning unit 8... Static eliminator 9... Recording paper 10
...Solvent tank 11...Solvent supply pump, 12
...Ultrasonic vibrator, 13...Blower fan, 14
...Solvent mist. Name of agent: Patent attorney Shigetaka Awano and one other person I4F-I
N herito recitation US drum stirrer dob-1 & numbing mist e raw 6 crimping roller cleaning]=nodowani electric sintering U paper shiki tank molten 1

Claims (3)

[Claims] (1) A toner for developing electrostatic images, which contains at least a binder and a colorant, and at least a portion of the binder composition is dissolved in water to reduce the viscosity. (2) At least a binder and a colorant are included, and at least a part of the binder composition has a higher solubility in alcohol or a mixed solvent of water and alcohol than in water. A toner for developing electrostatic images characterized by: (3) an image forming means for forming on an image carrier a toner image made of an electrostatic image developing toner whose viscosity is reduced by a mixed solvent of water and alcohol; and a solvent supply means for supplying the solvent to the toner image. 1. A recording apparatus comprising: a transfer unit that presses and transfers the toner image whose viscosity has been reduced by the solvent onto an image receptor.