JP2010262126A - Adhesive transferable liquid developer, image forming apparatus and image forming method - Google Patents

Abstract

An adhesive transferable liquid capable of suppressing image loss during transfer when used in an image forming method in which a toner image formed on an electrostatic latent image carrier is transferred with the adhesive force of toner particles. A developer, an image forming apparatus using the same, and an image forming method are provided.
SOLUTION: Acrylic acid ester monomer A / methacrylic acid ester monomer B / acrylic acid (methacrylic acid) benzyl ester C / acrylic acid (methacrylic acid) epoxy ester monomer D / acrylic acid (methacrylic acid) hydroxy ester monomer E = 5 An adhesive transferable liquid developer containing 20/40 to 80/2 to 20/2 to 16/2 to 25 (mol%) of a multi-component copolymer resin.
[Selection] Figure 1

Description

  The present invention comprises a toner particle containing a colorant and a resin and a liquid in which the toner particle is dispersed, and the electrostatic latent image is formed by attaching the toner particle to the electrostatic latent image on the electrostatic latent image carrier. An adhesive transferable liquid developer used for an image forming method in which a toner image is formed into a toner image, and the toner image formed on the electrostatic latent image carrier is transferred onto a transfer substrate with the adhesive force of the toner particles without heating. The present invention also relates to an image forming apparatus and an image forming method using the same.

  Today, as consumers' needs are diversifying, the tendency to demand a small quantity and a wide variety of production is also becoming more prominent. Thus, attention has been paid to an electrophotographic method that does not require a costly and time-consuming plate making process as a method for meeting such requirements.

  With the development of digital latent image forming technologies such as LEDs and laser beams in electrophotography, it is possible to write high-definition dot images such as 1200 DPI. An electrophotographic developer capable of forming a fine and high-quality image, an image forming method and an apparatus are desired.

  In order to obtain such a high-quality print, accurate reproducibility of the dot area is required, and the toner image is transferred from the latent image carrier or intermediate transfer member to a transfer substrate such as an intermediate transfer member or transfer paper. In particular, toner scattering and crushing (which also occurs during heating and pressure fixing) become a major problem particularly in color printing. A high-resolution toner image can be realized by reducing the particle size of the toner used. In addition, if toner particles having a fine particle size are used, the thickness of the toner image is reduced and the color expression in the case of obtaining a color print by color superposition is improved, and the toner transferred onto the transfer paper as the final recording medium As the image thickness decreases with the particle size, the degree of curling of the transfer paper and the cracking of the toner image is also improved.

  The toner particles include a powder toner that is triboelectrically charged with a powder carrier or the like and used in a dry development system, and a toner that is dispersed in a carrier liquid that is a liquid carrier and is used in a liquid development system (hereinafter referred to as a liquid toner). There is. Among these, in the case of powder toner, when the toner is a fine powder toner having a particle size on the order of 5 microns to sub-micron, it becomes difficult to suppress toner scattering and to remove residual toner on the photoreceptor as a latent image carrier after the transfer process. There is a problem. On the other hand, since liquid toner is used by dispersing toner particles in a carrier liquid, such a problem does not occur and handling as a fine toner is easy. Therefore, compared with dry electrophotography using powder toner, it can achieve high definition as high as a method capable of printing high-definition images such as gravure printing and offset printing. it can. Further, the lower the melting temperature of the toner is, the more advantageous for power consumption and speeding up, but there is a problem that powder toner with a low melting temperature causes blocking. On the other hand, since liquid toner is used by dispersing toner particles in a carrier liquid, a toner having a low melting point (low softening point) can be employed without such a problem.

  In the conventional developing method using liquid toner, an electrostatic latent image is developed by liquid development and the transfer paper is brought into contact with the surface of the photoreceptor on which the toner image is formed, and a corona discharge device, a transfer roller, etc. To form a transfer electric field. As a result, when an electrostatic transfer method for transferring the toner image on the photoconductor onto the transfer paper is used, the charged transfer paper may be electrostatically adsorbed to the photoconductor by being charged. there were. Further, as a result of pressure applied by a transfer roller or the like, the toner image may be crushed, and it may be difficult to faithfully reproduce, for example, the width of a fine line or the dot area.

  In addition, in a liquid development image forming apparatus using a conventional liquid toner, the image may be crushed and a high-definition image may not be obtained. A toner image composed of a developer layer containing not only toner particles but also carrier liquid is formed on the surface of the latent image carrier developed by the developer composed of toner particles and carrier liquid. To transfer a toner image on a latent image carrier formed by liquid development onto a transfer sheet or the like with an electric field, between the latent image carrier on which the transfer electric field is formed and a transfer partner such as a transfer sheet. That is, a proper amount of carrier liquid is necessary for the transfer gap.

  However, if the carrier liquid is excessive, the toner image such as dots and lines may be crushed, the line width may be widened, and the image density may be uneven. The toner image formed on the latent image carrier It is difficult to faithfully transfer to transfer paper or the like. This is because when the carrier liquid is excessively present on the surface of the latent image carrier, the electric field is insufficient at the same transfer potential difference as when the carrier liquid is small, and the toner particles constituting the toner image on the surface of the latent image carrier are transferred during transfer. This is thought to be caused by the inability to move faithfully to the latent image. In order to form a necessary electric field according to a large amount of carrier liquid, a problem that requires a higher voltage occurs.

  In addition, various types of transfer base materials such as transfer paper used for printing have been required. Not only plain paper, but also coated paper or resin film that is coated with white clay called `` clay '' on the surface to give gloss to the surface of the paper or improve smoothness as a transfer substrate It is expected to be used. Coated paper or resin film does not absorb the carrier liquid at all or absorbs less than plain paper because of its surface smoothness and material characteristics. For this reason, the transfer state may occur as in the case where there is a large amount of carrier liquid in the transfer gap, and the image may be crushed.

  In order to deal with such a problem, some conventional liquid development image forming apparatuses include a squeeze roller that removes excess carrier liquid from the surface of the latent image carrier. The configuration including the squeeze roller includes a method of rotating the latent image carrier so that the surface moves in a direction opposite to the latent image carrier, and a toner of the image portion. There has been proposed a method in which a roller provided with a potential difference that does not remove the toner is brought into contact with the toner image, and the carrier liquid is adhered and removed. Further, as a method for preventing the image from being crushed, the toner of the toner image formed on the latent image carrier is formed by causing a roller to which a voltage is applied to face the surface of the toner image on the latent image carrier with a gap. There is a method of transferring the toner image to a recording medium after increasing the solid content (see, for example, Patent Document 1 and Patent Document 2).

  Further, Patent Document 3 discloses a method in which a toner image on a latent image carrier or an intermediate transfer member is dried, and then a non-aqueous liquid carrier is supplied to the transfer substrate during transfer to perform electrostatic transfer. Proposed. By drying, the carrier liquid that exists between the toner particle particles forming the toner image evaporates and the toner particles aggregate, thereby increasing the interaction between the toner particles and supplying the non-aqueous carrier liquid. Then, electric field transfer is performed. When transferring to the transfer substrate, the toner particles do not behave individually and transfer as an aggregate of toner particles, so that the toner image is prevented from being crushed and spread, and a high-resolution and high-quality image can be obtained. it can.

  However, even when such a method for preventing crushing is used, when electrostatic transfer is performed by the liquid development method, the toner particles move from the surface of the latent image carrier to the transfer substrate. In order to migrate inside, a carrier liquid is required between the latent image carrier and the transfer substrate. Then, since the carrier liquid is present, the image is crushed, or the carrier liquid penetrates into the transfer paper that is the transfer substrate, the transfer paper swells, and the image is distorted.

  In view of this, there is a method described in Japanese Patent Application Laid-Open No. 2004-151620 as a method for performing transfer by a liquid developing method other than an electrostatic method. In Patent Document 4, there is a method called adhesion transfer, offset transfer, or the like in which the adhesiveness of the toner is increased by adjusting the glass transition temperature and adjusting the degree of drying of the liquid carrier, and transferring with the adhesive force. When the toner image is self-fixed, a rapid film formation is performed, and the toner image that becomes a film and behaves integrally is transferred by its adhesive force. Thus, if the transfer is performed with the adhesive force of the toner, the liquid other than the toner can be eliminated as much as possible before the transfer, and the image can be transferred satisfactorily without being crushed or left behind.

  However, even with the method described in Patent Document 4, a part of the toner image sometimes remains on the surface of the photosensitive member during transfer. This occurs because, even in a toner image formed on a film, the connection between the toner particles is weak, and a part of the toner image is peeled off from the film-like toner image and remains on the surface of the photoreceptor. When a part of the toner image remains on the surface of the photoreceptor, the image of that part is lost.

  The present invention has been made in consideration of the above circumstances, and its purpose is to use it in an image forming method in which a toner image formed on an electrostatic latent image carrier is transferred with the adhesive force of toner particles. It is another object of the present invention to provide an adhesive transferable liquid developer capable of suppressing image loss during transfer, an image forming apparatus using the same, and an image forming method.

In order to solve the above-mentioned problem, the invention according to claim 1 is directed to electrostatically attaching toner particles containing a colorant and a resin dispersed in a carrier liquid to an electrostatic latent image. In an adhesive transferable developer used in an image forming method in which a toner image is formed and the toner image is transferred onto a transfer substrate by the adhesive force of the toner particles.
The resin of the toner particles contains a copolymer having monomer A, monomer B, monomer C, monomer D and monomer E represented by the following general formulas (1) to (5) as constituent components To do.

(However, in the general formula (1), R represents H or CH _3, when R is H, n is 6-9 and R is CH _3, n represents from 10 to 14.)

(However, in general formula (2), n represents 6-8.)

(In the general formula (3), R represents H or CH _3. )

(However, in the general formula (4), R represents H or CH _3.)

(In the general formula (5), R represents H or CH _3. )

The invention according to claim 2 provides the adhesive transferable liquid developer according to claim 1,
Component ratio of the monomers A to E is monomer A / monomer B / monomer C / monomer D / monomer E = 5 to 20 mol% / 40 to 80 mol% / 2 to 20 mol% / 2 to 16 mol% / 2 to 25 mol% It is characterized by being.

Further, the invention of claim 3 is the adhesive transferable liquid developer according to claim 1 or 2,
The resin has a weight average molecular weight (Mw) of 20,000 to 50,000 and a number average molecular weight (Mn) of 10,000 to 40,000.

According to a fourth aspect of the present invention, in the adhesive transferable liquid developer according to any one of the first to third aspects,
The resin has a volume resistance of 1 × 10 ¹⁰ to 1 × 10 ¹⁶ Ω · cm.

According to a fifth aspect of the present invention, there is provided an electrostatic latent image forming means for forming an electrostatic latent image on the electrostatic latent image carrier, and a toner on the electrostatic latent image formed on the electrostatic latent image carrier. Supplying an adhesive transferable liquid developer containing particles to form a toner image of the electrostatic latent image, and a developer in the developer attached to the electrostatic latent image carrier on which the toner image is formed Excess liquid removing means for removing a part of the carrier liquid from the electrostatic latent image carrier and a toner image on the electrostatic latent image carrier from which a part of the carrier liquid has been removed are transferred onto a transfer substrate. In an image forming apparatus provided with a transfer unit,
The pressure-sensitive adhesive transferable liquid developer is the pressure-sensitive adhesive transferable liquid developer according to any one of claims 1 to 4.

According to a sixth aspect of the present invention, there is provided an electrostatic latent image forming step for forming an electrostatic latent image on the electrostatic latent image carrier, and a toner on the electrostatic latent image formed on the electrostatic latent image carrier. A developing step of supplying an adhesive transferable liquid developer containing particles to form a toner image of the electrostatic latent image; and the developer in the developer attached to the electrostatic latent image carrier on which the toner image is formed. An excess liquid removing step for removing a part of the carrier liquid from the electrostatic latent image carrier, and a toner image on the electrostatic latent image carrier from which a part of the carrier liquid has been removed is transferred onto a transfer substrate. In an image forming method comprising a transfer step,
The pressure-sensitive adhesive transferable liquid developer is the pressure-sensitive adhesive transferable liquid developer according to any one of claims 1 to 4.

  According to the present invention, a product obtained by reacting the monomer A, the monomer B, the monomer C, the monomer D, and the monomer E represented by the general formulas (1) to (5) as a resin component of the toner particles (copolymerization) The toner image formed on the electrostatic latent image carrier can be prevented from being lost during transfer when used in an image forming method in which the toner image is transferred with the adhesive force of the toner particles. An adhesive transferable liquid developer, an image forming apparatus and an image forming method using the same can be provided.

It is a figure for demonstrating the quality of the transfer property of a liquid developer. It is the schematic of the apparatus used for the measurement of the volume resistance of resin. 1 is a diagram illustrating a schematic configuration of an image forming apparatus according to a first embodiment of the present invention. It is a figure which shows schematic structure of the image forming apparatus which concerns on 2nd Embodiment by this invention. It is a figure which shows schematic structure of the image forming apparatus which concerns on 3rd Embodiment by this invention.

  As a result of studying the problem of image loss in the liquid development image forming apparatus, the present inventor reacted monomers A, B, C, D and E represented by the following general formulas (1) to (5). The toner image formed on the electrostatic latent image carrier is adhered to the toner particles by using an adhesive transferable liquid developer containing a resin containing the produced product (copolymer) as a resin component of the toner particles. It has been clarified that an image can be prevented from being lost at the time of transfer when used in an image forming method for transferring by force.

(However, in the general formula (1), R represents H or CH _3, when R is H, n is 6-9 and R is CH _3, n represents from 10 to 14.)

(However, in general formula (2), n represents 6-8.)

(In the general formula (3), R represents H or CH _3. )

(However, in the general formula (4), R represents H or CH _3.)

(In the general formula (5), R represents H or CH _3. )

  In particular, by using the above-mentioned adhesive transferable liquid developer, good transferability can be obtained regardless of the characteristics (resistance value, etc.) and surface properties (such as unevenness) of the transfer substrate, and fixing can be performed without heating. The carrier liquid in the toner layer is removed by squeezing the carrier liquid after development, and the toner liquid is appropriately adhered, and the toner image is appropriately transferred onto the transfer substrate, and the toner image is pressure-bonded to the transfer substrate with a pressure roller. Can be established. In order to realize non-heating adhesive transfer, it is important that when the carrier liquid in the developer is reduced, the toner layer exhibits adhesiveness and the toner layer is integrally transferred. Even if the toner layer is sticky, if it is divided in the toner layer, the transfer rate is lowered, and the target image density cannot be obtained. That is, as shown in FIG. 1, when the toner image 3 formed on the electrostatic latent image carrier 1 is transferred onto a transfer substrate 2 such as transfer paper, the transfer substrate 2A having a flat surface or unevenness is transferred. On the transfer substrate 2B having the surface, as shown in (C) and (D), the toner image 3 is divided at the middle part of the layer, and a part 3a remains on the electrostatic latent image carrier 1. There is a case. However, by using the adhesive transferable liquid developer according to the present invention, as shown in (A) and (B), it is possible to reliably transfer the entire amount of the toner image onto the transfer substrates 2A and 2B. It becomes.

  It is also important that the final fixed image does not remain sticky. For this reason, adhesiveness develops when a certain amount of carrier liquid is removed during transfer, and when the toner layer is integrally transferred onto the transfer substrate, an image with no adhesiveness is finally formed. It is necessary to do. By using the above-mentioned adhesive transferable liquid developer according to the present invention, it is possible to appropriately form an image having no adhesiveness.

  The monomer A constituting the reaction product (copolymer) serving as the resin component of the toner particles of the adhesive transferable liquid developer according to the present invention imparts adhesiveness during transfer, and the monomer B is a toner particle. This increases the affinity between the toner and the carrier liquid, and improves the dispersion stability of the toner particles in the liquid developer. In addition, the monomer C has an effect of promoting the film formation of the toner layer, integrating the toner layer during transfer, and strengthening the toner layer coating after fixing. As a result of the inventors' diligent research, a conventional adhesive transferable liquid developer is obtained by forming a polymer in which monomer C is branched and graft polymerized where monomer A and monomer B are copolymerized. It was found that a film-like toner image that is less prone to chipping of the toner image can be easily and reliably formed. However, since the monomer C cannot be directly graft-polymerized to the polymer in which the monomer A and the monomer B are copolymerized, the monomer D and the monomer E can be used as a role for linking the polymer and the monomer C. It is important.

Examples of the monomer A include hexyl acrylate, heptyl acrylate, octyl acrylate, 2-ethylhexyl acrylate, decyl methacrylate, undecyl methacrylate, lauryl methacrylate, tridecyl methacrylate, and tetradecyl methacrylate.
Examples of the monomer B include hexyl methacrylate, heptyl methacrylate, octyl methacrylate, and 2-ethylhexyl methacrylate.
Examples of the monomer C include benzyl acrylate and benzyl methacrylate.
Examples of the monomer D include glycidyl acrylate and glycidyl methacrylate.
Examples of the monomer E include acrylic acid and methacrylic acid.

  The monomer A imparts adhesiveness at the time of transfer, and when the component ratio in the copolymer is less than 5 mol%, the adhesive force is insufficient and the adhesive transferability tends to be lowered. If the amount of monomer A is more than 20 mol%, the effect of forming a film on the toner layer is hindered, and the ink layer is liable to be separated in the toner layer at the time of adhesive transfer or the printing surface becomes sticky after fixing. Therefore, the monomer A is desirably 5 mol% to 20 mol% in the copolymer component.

  Monomer B has the effect of increasing the affinity with the solvent in the toner, improving the dispersion stability of the toner, and suppressing the adhesiveness after fixing. When the component ratio of the monomer B in the copolymer is less than 40 mol%, the effect of dispersion stability is lowered, and when it is more than 80 mol%, the tackiness tends to be lowered and the adhesive conversion property tends to be inhibited. For this reason, the monomer B is desirably 40 mol% to 80 mol% in the copolymer component.

  Monomer C has an effect of promoting film formation of a toner layer for forming a toner image, integrating the toner layer during transfer, and strengthening the toner layer film after fixing. If the component ratio in the copolymer is less than 2 mol%, the effect of forming a film is small, resulting in poor transfer or fixing strength, and if it exceeds 20 mol%, the affinity with the solvent may be reduced and aggregation may occur. is there. For this reason, the monomer C is desirably 2 to 20 mol% in the copolymer component.

  Monomer D has the effect of making the resin skeleton grafted and crosslinked to increase the strength of the toner layer film at the time of transfer, or to adsorb and integrate it with the colorant. When the component ratio of the monomer D in the copolymer is less than 2 mol%, the effect is small, and when it is 16 mol% or more, the solvent affinity tends to decrease. For this reason, the monomer D is desirably 2 to 16 mol% in the copolymer component.

  The monomer E acts on the formation of a crosslinked structure by reaction with the monomer D, and has an effect on the film integration transfer property of the toner layer by hydrogen bonding of carboxylic acid. When the component ratio of the monomer E in the copolymer is less than 2 mol%, the effect is small, and when it is 25 mol% or more, the solvent affinity is lowered. For this reason, 2-25 mol% is desirable in the monomer E said copolymer component.

  The Tg (glass transition point) of the copolymer (resin component) obtained from these monomers A, B, C, D and E is preferably -20 ° C to 30 ° C. If the temperature is lower than -20 ° C, the image remains sticky even after fixing, and if it is higher than 30 ° C, the adhesive transfer property is lowered.

  Further, the structure of the copolymer obtained from the monomers A, B, C, D and E can vary depending on the polymerization method, but an example is the structure shown by the following general formula (6). . In the following general formula (6), a, b, c, d, and e are monomer component ratios (mol%) of the monomers A, B, C, D, and E, respectively.

  The weight average molecular weight (Mw) of the resin of the toner particles used in the present invention is preferably 10,000 to 100,000, particularly preferably 20,000 to 50,000. Further, the number average molecular weight (Mn) of the resin of the toner particles is preferably 10,000 to 80,000, and particularly preferably 10,000 to 40,000. When the weight average molecular weight (Mw) is less than 10,000 and the number average molecular weight (Mn) is less than 10,000, the adhesive transferability and the toner cohesive force at the time of transfer are reduced, while the weight average molecular weight (Mw) is 100,000 or more and the number average molecular weight. When (Mn) is 80000 or more, the dispersion stability is lowered. In this case, when the resin is partially grafted with monomers D and E to form a cross-linked structure, the cohesive force of the toner layer is increased, and even if there is a carrier liquid, good adhesive transferability can be exhibited. Here, the weight average molecular weight (Mw) and the number average molecular weight (Mn) are measured by GPC (gel permeation chromatograph) (manufactured by Shimadzu Corporation, CBM-20 / LC-20A / CTO-20A / RID-10A system). Can be measured by using.

Further, the volume resistance of the resin of the toner particles is desirably 1 × 10 ¹⁰ to 1 × 10 ¹⁶ Ω · cm. When the toner is less than 1 × 10 ¹⁰ Ω · cm, developability deteriorates. On the other hand, if it is higher than 1 × 10 ¹⁶ Ω · cm, the toner is poorly charged. Here, the volume resistance of the resin is measured by using the apparatus shown in FIG. 2 to fill the cell 5 having a 2 cm × 2 cm electrode plates 4A and 4B and an interelectrode distance of 5 mm with the resin to be measured, and applying a voltage of 500V. It calculated | required by the following formula from the electric current value which flows when it applied.

  Volume resistance (Ω · cm) = (applied voltage (500 V) / current value) × (electrode area (2 cm × 2 cm) / distance between electrodes (0.5 cm))

  The ratio between the colorant and the resin constituting the toner particles is preferably 1/1 to 1/5 in terms of mass ratio. If the ratio of the resin is less than 1/1, the adhesive transferability is lowered, and if it is more than 1/5, the toner coloring power is lowered.

  As the colorant, general inorganic / organic pigments and dyes can be used. For example, Printex V, Printex U, Printex G, Special Black 15, Special Black 4, Special Black 4-B (made by Degussa), Mitsubishi # 44, # 30, MR-11, MA-100 ( As above, such as Mitsubishi Kasei Co., Ltd., Raven 1035, Raven 1252, News Pect II (above, Columbia Carbon), Regal 400, 660, Black Pearl 900, 1100, 1300, Mogal L (above, Cabot) Inorganic pigments, phthalocyanine blue, phthalocyanine green, sky blue, rhodamine lake, malachite green lake, methyl violet lake, peacock blue lake, naphthol green B, naphthol green Y, naphthol yellow S, naphthol red, red 1st Yellow 2G, Permanent Red 4R, Brilliant First Scarlet, Hansa Yellow, Benzidine Yellow, Resol Red, Lake Red C, Lake Red D, Brilliant Carmine 6B, Permanent Red F5R, Pigment Scarlet 3B Indigo, Thioindigo Oil Pink and Bold Organic pigments such as -10B, Disperse Fast Yellow G, Disperse Blue FFR, Disperse Blue Green B, Disperse Yellow 5G, Disperse Red FB, Reactive Orange 2R, Reactive Red 3B, Reactive Blue 3G, Reactive And dyes such as Brilliant Blue R and Reactive Black B.

  These colorants preferably have a high purity, and more preferably 80% or more. Further, when it is desired to control the polarity and resistance of the colorant, flushing the colorant is also effective for controlling the chargeability of the toner particles. In the flushing treatment, a resin dispersion medium is further added to a water-containing liquid in which a colorant is dissolved in water, mixed well in a kneader called a flasher, and water existing around the pigment is added by a resin dispersion medium added later. This is the replacement process. The water taken out by this operation is discharged, the pigment is dispersed in the resin solution, dried, the solvent is removed, and the resulting mass is pulverized to obtain a colorant powder.

The ratio of the colorant to the resin during the flushing is suitably 10 to 60 parts by mass of the colorant with respect to 100 parts by mass of the resin. It is particularly advantageous to perform the flushing treatment in the presence of humic acid, a humic acid salt (Na salt, NH ₄ salt etc.) or a humic acid derivative. The amount of these humic acids added is suitably about 0.1 to 30% by mass of the colorant-containing liquid. The resin used in the flushing treatment is preferably a polyester resin, an epoxy resin, a polyolefin resin, or the like.

As the carrier liquid used in the liquid developer of the present invention, a high resistance and low dielectric constant is preferable, and isoparaffin hydrocarbon, liquid paraffin, polyalphaolefin, silicone oil and the like are preferable.
Isoparaffin hydrocarbons are Isopar C, Isopar E, Isopar G, Isopar H, Isopar L, Isopar M, Isopar V, Solvesso 100, Solvesso 150, Solvesso 200, Exor 100/140, Exor D30, Exor D40, Exor D80, Exor D110, Exor D130 (exxon mobile) are liquid paraffins such as Christol J52, J72, J102, J142, J172, J202 (ex Esso Petroleum), and polyalphaolefins are Syn2, Syn4. Syn6 (exxonmobile) and other silicone-based oils include KF96 1-10000 cst (Shin-Etsu Silicone), SH200, SH344 (above, Toray Silicone) And TSF451 (manufactured by Toshiba Silicone).

  The ζ potential of the toner is preferably 10 to 200 mV. When the ζ potential is lower than 10 mV, the toner particles aggregate, the electrophoretic property is lowered and the background is soiled, or the density is lowered. On the other hand, if the ζ potential is higher than 200 mV, the adhesion amount of the photosensitive member may decrease and the density may decrease.

  The average particle size of the toner particles is desirably 0.1 to 3 μm. If the average particle size is 0.1 μm or less, a sufficient concentration cannot be obtained or blurring is likely to occur. Resolution may deteriorate.

  The liquid developer of the present invention increases the solid content in the development process and the carrier liquid removal process, thereby expressing the adhesiveness of the toner particles, and enables adhesive transfer. On the other hand, after the toner particles are adhesively transferred to the transfer substrate and fixed, the carrier liquid is almost lost, and the adhesiveness is lost.

  Next, an image forming apparatus to which the adhesive transfer liquid developer according to the present invention can be applied will be described with reference to FIGS.

  FIG. 3 is a diagram showing a schematic configuration of the image forming apparatus according to the first embodiment of the present invention. The image forming apparatus 10 according to the first embodiment includes a charging voltage applying member 12 such as a charging charger, a developing device 13, a squeeze roller 14, a transfer device, and the like around a drum-shaped photoconductor 11 serving as an electrostatic latent image carrier. A roller 15, a transfer substrate separation roller 16, a cleaning blade 17, and a cleaning roller 18 are provided. Further, the image forming apparatus 10 includes an exposure device (not shown) that irradiates the photosensitive member 11 with exposure L corresponding to image information, and an unillustrated discharge device that irradiates exposure E that removes charges remaining on the surface of the photosensitive member 11. And a blower-B for drying and removing a part of the carrier liquid in the developer applied on the photoreceptor 11.

When an image is formed on a transfer substrate P such as transfer paper by such an image forming apparatus, the surface of the photoconductor 11 that is rotationally driven in the direction of arrow A is provided on the surface of the photoconductor 11 by the charging voltage applying member 12. The surface is uniformly charged to give a charge, and the exposure L erases the charge in the non-image area. As the photoconductor 11, a selenium photoconductor, an organic photoconductor, or an amorphous silicon photoconductor can be used. The surface potential of the photoreceptor is good in the range of 400V to 1600V. The liquid developer D supplied from the developing roller 13a rotating in the arrow B direction of the developing device 13 supplies toner particles to the remaining electrostatic latent image on the photoconductor 11 to form a toner image and develop it. Thereafter, the excess developer D is removed by the squeeze roller 14, and the toner image is transferred to the transfer substrate P by the adhesive force of the toner particles. In this case, the transfer pressure applied by the transfer roller 15 is preferably 0.1 to 10 kg / cm ² .

  The developing roller 13 a rotates in the forward direction with the photoconductor 11, and the squeeze roller 14 rotates in the direction opposite to the photoconductor 11. In this case, the linear speed with respect to the photosensitive member 11 is effectively 1.2 to 6 times that of the developing roller 13a, and the linear speed of the squeeze roller 14 is effectively 1.2 to 4 times. A gap G1 is formed between the developing roller 13a and the photoconductor 11, and the liquid developer D supplied between the developing roller 13a and the surface of the photoconductor 11 passes through the surface of the photoconductor 11 through the gap G1. Is applied and formed in a predetermined thickness. It is recommended that the gap G1 between the developing roller 13a and the surface of the photoreceptor 11 is 50 to 250 μm.

  Thus, the toner particles in the liquid developer D supplied to the surface of the photoconductor 11 by the developing roller 13a are electrostatically attracted to the surface side of the photoconductor 11, so that they are separated from the surface of the photoconductor 11. The liquid developer D on the side has a carrier liquid as a main component. The carrier liquid in the liquid developer D on the side separated from the surface of the photoconductor 11 is removed from the surface of the photoconductor 11 by a squeeze roller 14 that rotates reversely to the photoconductor 11. Thus, in order to remove the carrier liquid in the liquid developer D on the side separated from the surface of the photoconductor 11 from the surface of the photoconductor 11, the gap G2 is also formed between the squeeze roller 14 and the surface of the photoconductor 11. Is formed. The gap G2 is preferably 30 to 150 μm. After the developer D that has not been transferred and remains on the photoconductor 11 is removed by the cleaning blade 17 and the cleaning roller 18, the photoconductor 11 is discharged and the surface of the photoconductor 11 is set to an initial state. In this embodiment, as the exposure L, the charge of the image portion is left and the charge of the non-image portion is erased. However, an image can be formed in the same manner by a developing method that erases the charge of the image portion and leaves the charge of the non-image portion. .

  FIG. 4 is a diagram showing a schematic configuration of an image forming apparatus according to the second embodiment of the present invention. The image forming apparatus 20 according to the second embodiment is an example in which an intermediate transfer roller 21 is added as an intermediate transfer member to the image forming apparatus 10 according to the first embodiment shown in FIG. In the image forming apparatus 20 according to the second embodiment, an intermediate transfer roller 21 that rotates in the direction of arrow F is used. The toner image formed on the surface of the photoconductor 11 is transferred to the surface of the intermediate transfer roller 21, and the toner image transferred to the surface of the intermediate transfer roller 21 is transferred in the arrow direction H. The image is transferred by the transfer roller 22. In this embodiment, as the squeeze roller, the squeeze roller 14a that removes a part of the developer D without contacting the surface of the photoreceptor 11 and the surface of the photoreceptor 11 are in contact with the squeeze roller 14a. A squeeze roller 14b for removing the carrier liquid is used.

The material of the intermediate transfer roller 21 is preferably a solvent-resistant and elastic material such as urethane rubber, nitrile rubber, hydrin rubber, etc., and more preferably coated with a fluororesin. In the image forming apparatus 20 according to the second embodiment, a higher transfer pressure can be applied than in the image forming apparatus 10 according to the first embodiment shown in FIG. In this case, when a material having a low surface energy such as a fluororesin is used for the surface of the intermediate transfer roller 21, there is an advantage that when the toner image is transferred to the intermediate transfer roller 21, it can be highly solidified. The adhesive transfer property is improved as compared with the image forming apparatus 10 according to the embodiment. In this case, the primary transfer for transferring the toner image from the photoconductor 11 to the intermediate transfer roller 21 uses 100V to 1000V electrostatic transfer, the primary transfer pressure is 0.1 to 3 Kg / cm ² , and the transfer from the intermediate transfer roller 21 is performed. The secondary transfer pressure for transferring the toner image to the substrate P is preferably from 0.1 to 30 kg / cm ² .

  FIG. 5 is a diagram showing a schematic configuration of an image forming apparatus according to the third embodiment of the present invention. The image forming apparatus 30 according to the third embodiment is different from the image forming apparatus 10 according to the first embodiment shown in FIG. 3 in that the developing device 13 that supplies the liquid developer D from the developing roller 13a to the surface of the photoreceptor 11 is changed. is doing. That is, the liquid developer D is pumped from the container 13d that stores the liquid developer D by the pumping roller 13c, the liquid developer D pumped by the pumping roller 13c is transferred to the supply roller 13b, and further, a predetermined thickness is supplied from the supply roller 13b. The liquid developer D is transferred to the developing roller 13a, and the liquid developer D having a predetermined thickness is supplied from the developing roller 13a to the surface of the photoconductor 11. By using such a developing device 13, it is possible to supply and develop the liquid developer D in a thin layer on the surface of the photoreceptor 11. In this case, the layer thickness of the liquid developer D formed on the surface of the photoreceptor 11 is preferably about 1 to 15 μm, and preferably 3 to 10 μm. If the layer thickness is 1 μm or less, the density is not sufficient, and if it is 15 μm or more, the resolution is lowered.

  Further, in the image forming apparatus 30 according to the third embodiment, the carrier liquid removing roller (solvent removing roller) 23 is an intermediate for removing the carrier liquid of the liquid developer D adhered on the intermediate transfer roller 21. It is arranged to face the surface of the transfer roller 21. By providing such a carrier liquid removal roller 23, it is possible to more appropriately adjust the degree of adhesion of the toner image transferred onto the transfer substrate P.

  The image forming apparatus 30 according to the third embodiment is basically the same as the image forming apparatus 20 according to the second embodiment described above and the method of forming an image on the transfer substrate P, and thus the description thereof is omitted. In the image forming apparatus 30 according to the third embodiment, the electrostatic latent image is developed after corona discharge is applied to the electrostatic toner image liquid toner layer (liquid developer D) formed on the developing roller 13a. As a result, the cohesive force of the toner particles can be improved and the resolution can be increased. This corona discharge is highly effective when it has the same polarity as the toner particles, and the voltage is preferably about 500 to 8000V.

  The electrophotographic liquid developer according to the present invention can be charged, dispersed, and kneaded with a colorant, a resin, a carrier liquid, and a charge control agent, if necessary, in a dispersing machine such as a ball mill, a kitty mill, a disk mill, or a pin mill. Can do. In this case, the blending ratio of the above materials is preferably 5 to 20% by mass of the colorant, 5 to 40% by mass of the resin, 65 to 95% by mass of the carrier liquid, and 0.1 to 1% by mass of the charge control agent. If the developer is supplied as it is or diluted to an appropriate ratio and supplied to the developing device to form an image, an appropriate image can be formed.

  Next, the adhesive transferable developer according to the present invention will be described based on specific examples and comparative examples. First, (resin synthesis example 1) to (resin synthesis example 5) and (resin synthesis comparison example 1) to (resin synthesis comparison example 3) will be described as examples of toner particle resin synthesis. In addition, "part" of the compounding quantity of each following Example and a comparative example shows a mass part.

(Resin synthesis example 1)
A 0.5 L flask equipped with a stirrer, thermometer, condenser, and dropping funnel was charged with 300 g of Isopar H, heated to 90 ° C. and stirred with 0.02 mol of lauryl methacrylate (monomer A) and 2-ethylhexyl methacrylate. (Monomer B) A monomer solution consisting of 0.23 mol, glycidyl methacrylate (monomer D) 0.04 mol, methacrylic acid (monomer E) 0.01 mol, and benzoyl peroxide (reaction initiator) 1 g was added dropwise over 2 hours. . After the dropping, polymerization was carried out for 5 hours while maintaining the temperature at 95 ° C. Thereafter, a monomer solution consisting of 0.08 mol of benzyl methacrylate (monomer C) and 0.5 g of azbisisobutyronitrile (reaction initiator) was dropped over 1 hour, and polymerization was carried out for 1 hour while maintaining at 85 ° C. The polymerization rate of the synthesized resin was 97%, the molecular weight (Mn) was 22000, and (Mw) was 39000.

(Resin synthesis example 2)
A 0.5 L flask equipped with a stirrer, thermometer, condenser, and dropping funnel was charged with 320 g of Cristol J72, heated to 105 ° C. and stirred with 0.08 mol of tridecyl methacrylate (monomer A), heptyl methacrylate. From (monomer B) 0.16 mol, benzyl acrylate (monomer C) 0.02 mol, glycidyl methacrylate (monomer D) 0.06 mol, methacrylic acid (monomer E) 0.06 mol, benzoyl peroxide (reaction initiator) 1 g The resulting monomer solution was added dropwise over 3 hours. After the dropping, polymerization was carried out for 5 hours while maintaining the temperature at 100 ° C. The polymerization rate of the synthesized resin was 98%, the molecular weight (Mn) was 11000, and (Mw) was 21000.

(Resin synthesis example 3)
A 0.5 L flask equipped with a stirrer, thermometer, condenser, and dropping funnel was charged with 270 g of Exol D130, heated to 80 ° C., and stirred with 0.05 mol of 2-ethylhexyl acrylate (monomer A) and hexyl methacrylate (monomer). B) 0.30 mol, benzyl methacrylate (monomer C) 0.01 mol, glycidyl acrylate (monomer D) 0.04 mol, methacrylic acid (monomer E) 0.02 mol, benzoyl peroxide (reaction initiator) 0.5 g The monomer solution was added dropwise over 3 hours. After the dropwise addition, polymerization was carried out for 5 hours while maintaining the temperature at 85 ° C. The polymerization rate of the synthesized resin was 98%, the molecular weight (Mn) was 39000, and (Mw) was 49000.

(Resin synthesis example 4)
A 0.5 L flask equipped with a stirrer, thermometer, condenser, and dropping funnel was charged with 350 g of isododecane, heated to 85 ° C., and stirred with 0.03 mol of tetradecyl methacrylate (monomer A) and 2-ethylhexyl methacrylate ( A monomer solution consisting of 0.31 mol of monomer B, 0.01 mol of glycidyl methacrylate (monomer D), 0.01 mol of methacrylic acid (monomer E) and 1 g of benzoyl peroxide (reaction initiator) was added dropwise over 2 hours. After the dropwise addition, polymerization was carried out for 5 hours while maintaining the temperature at 85 ° C. Thereafter, a monomer solution consisting of 0.03 mol of benzyl acrylate (monomer C) and 0.3 g of azbisisobutyronitrile (reaction initiator) was added dropwise over 1 hour, and polymerization was carried out for 2 hours while maintaining the temperature at 80 ° C. The polymerization rate of the synthesized resin was 98%, the molecular weight (Mn) was 28000, and (Mw) was 46000.

(Resin synthesis example 5)
A 0.5 L flask equipped with a stirrer, thermometer, condenser, and dropping funnel was charged with 350 g of Isopar M, heated to 85 ° C., and stirred with decyl methacrylate (monomer A) 0.05 mol, 2-ethylhexyl methacrylate ( A monomer solution consisting of monomer B) 0.20 mol, glycidyl methacrylate (monomer D) 0.05 mol, methacrylic acid (monomer E) 0.10 mol, and benzoyl peroxide (reaction initiator) 1 g was added dropwise over 2 hours. After the dropwise addition, polymerization was carried out for 5 hours while maintaining the temperature at 85 ° C. Thereafter, a monomer solution consisting of 0.01 mol of benzyl acrylate (monomer C) and 0.4 g of azbisisobutyronitrile (reaction initiator) was added dropwise over 1 hour, and the polymerization was carried out for 2 hours while maintaining the temperature at 80 ° C. The polymerization rate of the synthesized resin was 97%, the molecular weight (Mn) was 34000, and (Mw) was 43000.

(Resin synthesis comparative example 1)
A 0.5 L flask equipped with a stirrer, thermometer, condenser, and dropping funnel was charged with 320 g of ISOPAR L, heated to 105 ° C. and stirred with 0.01 mol of stearyl methacrylate (monomer A) and octyl methacrylate (monomer B) 0.20 mol, methyl methacrylate (not applicable) 0.15 mol, glycidyl methacrylate (monomer D) 0.03 mol, methacrylic acid (monomer E) 0.02 mol, benzoyl peroxide (reaction initiator) 1 g The monomer solution was added dropwise over 3 hours. After the dropping, polymerization was carried out for 5 hours while maintaining the temperature at 100 ° C. The polymerization rate of the synthesized resin was 97%, the molecular weight (Mn) was 15000, and (Mw) was 27000.

(Resin synthesis comparative example 2)
A 0.5 L flask equipped with a stirrer, thermometer, condenser, and dropping funnel was charged with 290 g of Isopar H, heated to 85 ° C., stirred with stirring, 0.35 mol of 2-ethylhexyl methacrylate (monomer B), styrene (not applicable) ) A monomer solution consisting of 0.02 mol, glycidyl acrylate (monomer D) 0.03 mol, methacrylic acid (monomer E) 0.02 mol, and benzoyl peroxide (reaction initiator) 0.5 g was added dropwise over 3 hours. After the dropwise addition, polymerization was carried out for 5 hours while maintaining the temperature at 85 ° C. The polymerization rate of the synthesized resin was 95%, the molecular weight (Mn) was 31000, and (Mw) was 48000.

(Resin synthesis comparative example 3)
A 0.5 L flask equipped with a stirrer, thermometer, condenser, and dropping funnel was charged with 290 g of Isopar H, heated to 85 ° C., and stirred with butyl methacrylate (not applicable) 0.36 mol, benzyl acrylate (not applicable) ) A monomer solution consisting of 0.05 mol, glycidyl acrylate (monomer D) 0.04 mol, methacrylic acid (monomer E) 0.03 mol, and benzoyl peroxide (reaction initiator) 0.5 g was added dropwise over 3 hours. After the dropwise addition, polymerization was carried out for 5 hours while maintaining the temperature at 85 ° C. The polymerization rate of the synthesized resin was 96%, the molecular weight (Mn) was 20000, and (Mw) was 37000.

[Example 1]
Phthalocyanine blue (PB-15: 3, manufactured by Dainichi Seika Co., Ltd.) 14 parts Resin of resin synthesis example 1 (solid content 19.5%) 215 parts Isopar H (made by ExxonMobil) 25 parts Charge control agent (phosphatidyl) 3 parts were placed in a ball mill and dispersed for 72 hours, and then 30 parts of Isopar H was further added and dispersed for 1 hour. This was used as a concentrated liquid developer.

Image formation was performed with the image forming apparatus 10 shown in FIG. 3 described above using a developer obtained by mixing 100 g of this concentrated liquid developer and Isopar H, 1 L. In this case, adhesive transfer was performed on Ricoh paper 70W at a transfer developer solid content of 92% and a transfer pressure of 2 kg / cm ² .

[Example 2]
The same procedure as in Example 1 was performed except that image formation and adhesive transfer were performed with the image forming apparatus 20 shown in FIG. The primary transfer was performed by electrostatic transfer at an applied voltage of 200 V, and the secondary transfer was performed by adhesive transfer at a transfer pressure of 8 kg / cm ² . The developer solid content at the time of secondary transfer was 97%.

Example 3
Quinacridone red (PR-122, manufactured by Fuji Dye Co., Ltd.) / Polyester resin (manufactured by Mitsubishi Rayon Co., Ltd.) Flushing kneaded material (ratio 1/1) 30 parts Resin of resin synthesis example 2 (solid content 17.3%) 173 parts J72 (manufactured by Esso Petroleum Corporation) 20 parts Charge control agent (zirconium naphthenate, manufactured by Nippon Chemical Industry Co., Ltd.) Place 2 parts in a ball mill and disperse for 90 hours, then add 30 parts of Cristol J72 and disperse for 1 hour. Was used as a concentrated liquid developer.

The concentrated liquid developer was developed in a thin layer by the image forming apparatus 30 shown in FIG. 5 to form an image. In this case, the primary transfer was electrostatic transfer at an applied voltage of 300 V, and the secondary transfer was adhesive transfer to an RHP-made OHP sheet at a transfer pressure of 5 kg / cm ² . The developer solid content during the secondary transfer was 80%.

Example 4
Disperse Blue 60 (DB-60, manufactured by Arimoto Chemical Co., Ltd.) 15 parts Resin of resin synthesis example 3 (solid content 19.9%) 151 parts Exol D130 (manufactured by ExxonMobil) 5 parts Charge control agent (cobalt naphthenate) 3 parts in a basket mill and dispersed for 5 hours, 5 parts of Exol D130 was further added and dispersed for 1 hour, and this was used as a concentrated liquid developer.

Image formation was performed with the image forming apparatus 20 shown in FIG. 4 using a developer obtained by mixing 200 g of this concentrated liquid developer and Exol D130, 1L. The primary transfer was performed by electrostatic transfer at an applied voltage of 300 V, and the secondary transfer was performed by adhesive transfer to polyester satin at a transfer pressure of 10 kg / cm ² . The developer solid content at the time of secondary transfer was 96%.

Example 5
Naphthol Red (PR-184, Clariant) 18 parts Resin of Resin Synthesis Example 4 (solid content 17.6%) 511 parts Isododecane (ExxonMobil Corporation) 20 parts Charge Control Agent (Zirconium Naphthenate, Nippon Chemical) 2 parts were placed in a ball mill and dispersed for 96 hours, and then 30 parts of isododecane was further added and dispersed for 1 hour to obtain a concentrated liquid developer.

The concentrated liquid developer was developed in a thin layer by the image forming apparatus 30 shown in FIG. 5 to form an image. The primary transfer was electrostatic transfer at an applied voltage of 300 V, and the secondary transfer was adhesive transfer to a brass plate having a thickness of 0.5 mm at a transfer pressure of 8 kg / cm ² . The developer solid content during secondary transfer was 95%.

Example 6
Naphthol Red (PR-184, Clariant) / Epoxy resin (Japan Epoxy Resin) Flushing kneaded product (ratio 1/1) 34 parts Resin of resin synthesis example 5 (solid content 12.0%) 425 parts Isopar M (ExxonMobil Co., Ltd.) 5 parts Charge control agent (Zirconium naphthenate, Nippon Chemical Industry Co., Ltd.) Place 2 parts in a ball mill, disperse for 90 hours, add 5 parts of Isopar M, disperse for 1 hour, and concentrate A liquid developer was obtained.

The concentrated liquid developer was developed in a thin layer by the image forming apparatus 30 shown in FIG. 5 to form an image. The primary transfer was electrostatic transfer with an applied voltage of 300 V, and the secondary transfer was adhesive transfer to high-coat paper at a transfer pressure of 6 kg / cm ² . The developer solid content at the time of secondary transfer was 96%.

[Comparative Example 1]
Phthalocyanine blue (PB-15: 3, manufactured by Dainichi Seika Co., Ltd.) 14 parts Resin of resin synthesis comparative example 1 (solid content 22.1%) 190 parts Isopar H (manufactured by ExxonMobil) 30 parts Charge control agent (Phosphat 3 parts were placed in a ball mill and dispersed for 72 hours, and then 30 parts of Isopar H was further added and dispersed for 1 hour to obtain a concentrated liquid developer.

An image was formed by the image forming apparatus 20 shown in FIG. 3 using a developer obtained by mixing 100 g of this concentrated liquid developer toner and Isopar H and 1 L. Adhesive transfer was performed on Ricoh paper 70W at a transfer developer solid content of 90% and a transfer pressure of 6 kg / cm ² .

[Comparative Example 2]
Disperse Blue 60 (DB-60, manufactured by Arimoto Chemical Co., Ltd.) 15 parts Resin of resin synthesis comparative example 2 (solid content 25.6%) 117 parts Exol D130 (manufactured by ExxonMobil) 40 parts Charge control agent (naphthenic acid) (Cobalt, manufactured by Nippon Kagaku Sangyo Co., Ltd.) After 3 parts were placed in a basket mill and dispersed for 5 hours, 40 parts of Exol D130 was further added and dispersed for 1 hour to obtain a concentrated liquid developer.

Image formation was performed with the image forming apparatus 20 shown in FIG. 4 using a developer obtained by mixing 200 g of this concentrated liquid developer and Exol D130, 1L. Primary transfer was performed by electrostatic transfer at an applied voltage of 300 V, and secondary transfer was performed by adhesive transfer to polyester satin at a transfer pressure of 10 kg / cm ² . The developer solid content during the secondary transfer was 92%.

[Comparative Example 3]
Disperse Blue 60 (DB-60, manufactured by Arimoto Chemical Co., Ltd.) 15 parts Resin of resin synthesis comparative example 3 (solid content 26.6%) 113 parts Exol D130 (manufactured by ExxonMobil) 40 parts Charge control agent (naphthenic acid) (Cobalt, manufactured by Nippon Kagaku Sangyo Co., Ltd.) After 3 parts were placed in a basket mill and dispersed for 5 hours, 40 parts of Exol D130 was further added and dispersed for 1 hour to obtain a concentrated liquid developer.

Image formation was performed with the image forming apparatus 20 shown in FIG. 4 using a developer obtained by mixing 200 g of this concentrated liquid developer and Exol D130, 1L. Primary transfer was performed by electrostatic transfer at an applied voltage of 300 V, and secondary transfer was performed by adhesive transfer to polyester satin at a transfer pressure of 10 kg / cm ² . The developer solid content at the time of secondary transfer was 93%.

  Regarding the volume resistance of the resin used in the liquid developer of each Example and Comparative Example, the average particle diameter of the obtained toner particles, the charge control rate when the image was formed with the liquid developer, the transfer rate, and the image density Evaluation was performed by the following evaluation method. The results are shown in Table 1.

<Evaluation methods>
(1) Resin resistance (Ω · cm) was measured by the method described above.
(2) The average particle size of the toner particles is obtained by using Shimadzu Sa-CP3, and diluting the liquid developer with Isopar until the transmittance is about 15% with an integrating sphere turbidimeter, and then using the Sa-CP3 cell. Fill. The measurement conditions were ACCEL480, MODE: CENT, 3-16 channels.
(3) The charge control rate is calculated by the electrodeposition method. The electrodeposition conditions were as follows: electrode distance: 1 cm, electrode area: 2 cm × 2 cm, electrodeposition time: 100 seconds.
(4) The transfer rate was calculated from the following equation based on the concentration by the tape peeling method.
Transfer rate = (density on photoreceptor before transfer−residual density on photoreceptor after transfer) / (density on photoreceptor before transfer) × 100%
(5) The image density was measured by X-Rite.

  As is apparent from the results in Table 1 above, as a result of image formation using the liquid developer of each example according to the present invention using the image forming apparatus according to the first to third embodiments, charge controllability, non-heating Adhesive transfer was good and printing with high image density became possible. In addition, since the toner layer is integrated and transferred without being restricted by the material (resistance value, etc.) of the transfer substrate, good transfer can be performed even on uneven substrates. The consideration result about each Example and a comparative example is shown below.

  Since Example 1 uses the liquid developer of the present invention, adhesive transferability is good, but transferability is lower than that of Example 2 because of direct transfer from the photoreceptor. As can be seen from the results of Example 2, it is considered that the intermediate transfer member has lower surface energy than the photosensitive member, the toner layer has good releasability, and pressure is applied during transfer. In Example 3, since the ratio of the adhesive resin was low, the transfer rate was slightly lowered. In Example 4, although the transfer base material was an uneven cloth, the images were formed into a film and transferred integrally. Example 5 was able to transfer at a high transfer rate even to a metal transfer substrate which is difficult to electrostatic transfer. In Example 6, since the ratio of the monomer E was high, the toner charging rate slightly decreased.

  In Comparative Example 1, since the material of the present invention was not used, no tackiness was exhibited, toner characteristics non-heat-adhesive transfer could not be performed, and toner characteristics were not good. In Comparative Example 2, since there was no monomer A component of the present invention, the adhesiveness was not expressed and the adhesive transfer was not performed. Further, since there was no monomer C component, the film was not formed into a film and split in the toner layer, and the resin developability was poor because the resin resistance was low. In Comparative Example 3, the solvent affinity of the synthetic resin was low, the toner particle size was large due to aggregation, the developability was poor, the transfer layer was soft, and the image after fixing was sticky.

DESCRIPTION OF SYMBOLS 1 Electrostatic latent image carrier 2, 2A, 2B Transfer base material 3, 3a, 3b Toner layer 4A, 4B Electrode plate 5 Cell 10, 20, 30 Image forming apparatus 11 Photoconductor 12 Charging voltage applying member 13 Developing apparatus 13a Development Roller 13b Supply roller 13c Pumping roller 13d Container 14, 14a, 14b Squeeze roller 15, 22 Transfer roller 16 Transfer base material separation roller 17 Cleaning blade 18 Cleaning roller 21 Intermediate transfer roller 23 Carrier liquid removal roller (solvent removal roller)

Japanese Patent No. 2990675 JP-A-9-204109 JP-A-2-272476 Special table 2001-501654 gazette

Claims (6)

The toner particles containing the colorant and the resin dispersed in the carrier liquid are electrostatically attached to the electrostatic latent image to form the electrostatic latent image, and the toner image is transferred by the adhesive force of the toner particles. In the adhesive transferable developer used in the image forming method for transferring onto a substrate,
The resin of the toner particles contains a copolymer having monomer A, monomer B, monomer C, monomer D and monomer E represented by the following general formulas (1) to (5) as constituent components Adhesive transferable liquid developer.

(However, in the general formula (1), R represents H or CH _3, when R is H, n is 6-9 and R is CH _3, n represents from 10 to 14.)

(However, in general formula (2), n represents 6-8.)

(In the general formula (3), R represents H or CH _3. )

(However, in the general formula (4), R represents H or CH _3.)

(In the general formula (5), R represents H or CH _3. ) In the adhesive transferable liquid developer according to claim 1,
Component ratio of the monomers A to E is monomer A / monomer B / monomer C / monomer D / monomer E = 5 to 20 mol% / 40 to 80 mol% / 2 to 20 mol% / 2 to 16 mol% / 2 to 25 mol% A pressure-sensitive adhesive transferable liquid developer. In the adhesive transferable liquid developer according to claim 1 or 2,
The adhesive transferable liquid developer, wherein the resin has a weight average molecular weight (Mw) of 20,000 to 50,000 and a number average molecular weight (Mn) of 10,000 to 40,000. In the adhesive transferable liquid developer according to any one of claims 1 to 3,
The adhesive transferable liquid developer, wherein the resin has a volume resistance of 1 × 10 ¹⁰ to 1 × 10 ¹⁶ Ω · cm. Electrostatic latent image forming means for forming an electrostatic latent image on the electrostatic latent image carrier, and adhesive transferable liquid development containing toner particles in the electrostatic latent image formed on the electrostatic latent image carrier The developer is supplied to form a toner image of the electrostatic latent image, and a part of the carrier liquid in the developer attached to the electrostatic latent image carrier on which the toner image is formed is transferred to the electrostatic latent image. An image forming apparatus comprising: excess liquid removing means for removing from the latent image carrier; and transfer means for transferring the toner image on the electrostatic latent image carrier from which a part of the carrier liquid has been removed onto a transfer substrate. In
The image forming apparatus according to claim 1, wherein the adhesive transferable liquid developer is the adhesive transferable liquid developer according to claim 1. An electrostatic latent image forming step for forming an electrostatic latent image on the electrostatic latent image carrier, and an adhesive transferable liquid developer containing toner particles in the electrostatic latent image formed on the electrostatic latent image carrier A developing step of supplying a developer to form the electrostatic latent image into a toner image, and a part of the carrier liquid in the developer attached to the electrostatic latent image carrier on which the toner image is formed Image forming method comprising: excess liquid removing step for removing from latent image carrier; and transfer step for transferring toner image on electrostatic latent image carrier from which part of carrier liquid has been removed onto transfer substrate In
5. The image forming method according to claim 1, wherein the adhesive transferable liquid developer is the adhesive transferable liquid developer according to claim 1.

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