WO1997043697A1

WO1997043697A1 - Developer

Info

Publication number: WO1997043697A1
Application number: PCT/JP1996/001257
Authority: WO
Inventors: Kimikazu Nagase; Tatsuro Tsuchimoto; Satoshi Yoshida
Original assignee: Toray Industries, Inc.
Priority date: 1996-05-13
Filing date: 1996-05-13
Publication date: 1997-11-20
Also published as: EP0838731A1; KR19990028919A

Abstract

A developer comprising at least colored particles composed of a resin and a colorant dispersed in an insulating fluid, wherein the difference in kinematic viscosity between the temperatures of 10 °C and 50 °C is at most 4 cst and the kinematic viscosity at 20 °C ranges from 1.0 to 5 cst. It is stable irrespective of temperature and process fluctuations.

Description

Description Developer Technical Field

The present invention relates to a developer used for a copying machine or a laser beam printer. In particular, the present invention provides a visible image obtained by supplying a developer to the electrostatic latent image on the electrostatic latent image carrier through a developing roller and developing the latent image, and having a silicone rubber layer on the surface. The present invention relates to a developer used in an image forming method in which a transfer image on an intermediate transfer member is electrostatically transferred while being in contact with an intermediate transfer member, and then a transfer image on the intermediate transfer member is re-transferred onto a material to be transferred. Background art

Conventionally, a saturation developing method has been employed in which the latent image charges on the electrostatic latent image carrier and the electrostatic recording paper are sufficiently developed until the toner particles are neutralized. This method has the advantage that, if the charging characteristics of the toner in the developer are controlled, a stable development temperature can be obtained, and that there is no significant influence on the temperature change of the printer. However, in the case of the saturated developing method, it takes a long time for the developing to reach saturation, so that there is a problem that the printing speed of the printer cannot be increased.

To solve such a problem, as disclosed in Japanese Patent Application Laid-Open No. H5-2738865, the development time and the development speed are balanced by using a developing machine with a mouth color. A method has been proposed in which development is performed in a state where saturation is not reached, thereby increasing the printing speed.

However, when such a method is used, the development speed of the developer changes due to a change in the printer temperature, which causes problems such as the generation of alum in the development density, and the problem of increasing the printing speed. process varies Tsu by the bets, because Kagekyo is occurs say problems been filed in development density, the disclosure of _c invention a stable developer against the variations in temperature and process has been desired

An object of the present invention is to provide a developer having a small difference in developability due to temperature and process fluctuations. These objects are achieved by the present invention described below. That is, the present invention relates to a developer in which colored particles composed of at least a resin and a colorant are dispersed in an insulating liquid, and the kinematic viscosity of the developer at 50 ° C. The developer is characterized in that the difference in the values is less than 4 cst and the kinematic viscosity at 20 ° C is 1 cst or more and 5 cst or less. BEST MODE FOR CARRYING OUT THE INVENTION

The developer of the present invention is obtained by dispersing 0.1 to 10 wt% of a colored absorptive having a pigment and a resin as main components in an insulating liquid, preferably 0.5 to 5 wt%. It is a thing that did.

When the dispersion amount of the colored particles is less than 0.1 wt%, the problem occurs when the printing unevenness is reduced, and when the dispersion amount exceeds 10 wt%, the problem occurs when white background stain occurs. Occurs.

Regarding the kinematic viscosity of the developer, the difference between the value at 10 ° C. and the value at 50 is preferably 4 cst or less, and more preferably 3 cst or less. In addition, the kinematic viscosity at 20 ° C is preferably not less than l e st and not more than 5 c st, and more preferably not less than 1.5 c st and not more than 4 c st.

Here, if the kinematic viscosity at 20 ° C is less than 1 cst, the roller is rotated mechanically, for example, in the opposite direction, to remove the developer from the non-image area on the static latent image carrier. If the removal is attempted by one, the removal efficiency is poor due to the low viscosity, and the developer remains in the non-image area, causing a problem that white background stains occur. If it exceeds 5 cst, the mobility of the colored particles in the developer decreases, so that the time required for development becomes longer and the printing speed of the printer decreases.

If the difference between the kinematic viscosity value at 10 ° C and the value at 50 ° C exceeds 4 cst, the development time, such as supplying the developer via the developing roller and developing, is set. In an image forming method in which development is performed while balancing development speeds, the developability depends on the mobility of toner particles in the developer. Since this mobility depends on the viscosity of the solvent, the temperature dependence of the kinematic viscosity is linked to the temperature dependence of the development temperature, and the problem arises when the printing port of the printed material changes depending on the temperature. Occurs. To obtain the developer of the present invention, arbitrary favored and this volume resistivity and the insulating liquid using 1 0 ^'4 Ω · cm or more hydrocarbon solvents. The solvent has a dry point of 280 ° C or less, preferably 270 ° C or less, and an initial boiling point of 180 ° C or more, preferably 200 ° C or less. A temperature of at least ° C is preferred.

Here, when the initial boiling point in the distillation was less than 180, the developer was supplied to the electrostatic latent image on the electrostatic latent image carrier via a developing roller, and developed. An image forming method in which a visible image is statically transferred while being in contact with an intermediate transfer member having a silicone rubber layer on its surface, and then the transferred image on the intermediate transfer member is re-transferred onto a transfer material. However, since the solvent volatilizes on the static latent image carrier, the portability of the developer at the time of transfer to the intermediate transfer body changes, so that the transfer becomes unstable.

If the dry point in distillation exceeds 280 ° C, the solvent must be volatilized during transfer-fixing from the intermediate transfer member to paper. Not preferred for configuration.

If the volume resistivity is less than 1 · cm, the toner in the developer cannot be sufficiently electrophoresed, and the latent image cannot be sufficiently developed.

Also, solvents other than hydrocarbon solvents are not preferred in terms of safety, chemical stability, cost, and the like.

Examples of such hydrocarbon-based solvents are as follows: M (manufactured by Exxon Chemical Co., Ltd.), JWS 8947 (manufactured by Etsuso Oil Co., Ltd.), and Isosol 400 (manufactured by Nippon Petrochemical Co., Ltd.), NP—LC, NP-HCS. NP—SH (manufactured by Mitsui Texaco Chemical Co., Ltd.), AS-4 (manufactured by Nippon Yushi Co., Ltd.), etc. are preferred. More preferred is ISONO, I-M, JWS — 8947, ISO 400, NP-LC, NP — HCS, NP — SH, NAS — 4, and more preferred. Or JWS — 8 9 4 7, NP — HCS

Further, the amount of normal paraffin in the hydrocarbon solvent is preferably 70 wt% or more, more preferably 80 wt% or more.

If the amount of normal paraffins in the hydrocarbon solvent is less than 70 wt%, the discharge will not occur in the case of electrophotography in which the electrostatic latent image carrier is uniformly charged by corona discharge. A problem arises that the electrodes are easily contaminated. This is the problem of ozone generation due to corona discharge. It is thought to be related to

In addition, the composition of the normal fins should be 80 wt% or more, preferably 90 wt% or more, when the number of power rods is 12 13 14. I like it.

When the number of carbons is less than 8 O wt%, the temperature difference between the initial boiling point and the dry point is widened, and the stability of transfer to the intermediate transfer body and transfer to paper are increased. The balance of fixability may not be able to be obtained.

Further, it is preferable that the extract obtained by extracting the hydrocarbon solvent with dimethyl sulfoxide has an ultraviolet absorbance of 0.1 or less at a wavelength of 260 to 350 nm.

If the UV absorbance at a wavelength of 260 nm O nm of an extract obtained by extracting a hydrocarbon solvent with dimethyl sulfoxide exceeds 0.1, it is considered to be due to an effect such as corona discharge. However, when the solvent is colored during long-term running, problems may occur, especially when used in a full-color printer, etc., and the problem of color turbidity may occur. is there. Furthermore, problems arise when the aromatic component considered as such an extracted component generates an off-flavor.

The average particle size of the colored particles used in the present invention is 0.1 to 2.5 m, preferably 0.5 to 2 m.

In the image forming method using the intermediate transfer member, the latent image on the static latent image carrier is transferred to the intermediate transfer member during transfer of the toner from the electrostatic latent image carrier to the intermediate transfer member. The pressure is applied to the latent image due to contact. For this reason, when the average particle size is less than 0.1 / m, the amount of solvent existing between the particles is small, the strength of the latent image cannot withstand the pressure during transfer, and the tail in the printing direction is Dot tailing like pulling occurs. When the average particle size exceeds 2.5 m, the particle size of the toner for the pixel becomes large, and the image becomes rough such as a fine line of a printed matter. ·

The colored particles are preferably pigments or dyes and a resin whose main component is <, and colored particles in which the pigment is dispersed in the resin are preferable. The ratio of the pigment in the abduction is preferably 5 wt% or more and 30 wt% or less.

If the pigment content is less than 5 wt%, the coloring power is insufficient.If the pigment content is more than 30 wt%, the resin component is reduced, so that fixing is not sufficient and the gloss of printed matter is reduced. Occurs. Alkyl resin, styrene resin, phenol resin, acryl resin, styrene-acryl resin, polyester resin, rosin-modified phenol resin It is preferable to use a rosin-modified maleic resin such as a rosin-modified maleic resin.

General pigments and dyes are used.

-~ Tuck (For commercial products, for example, Mitsubishi Kasei Corporation # 30, # 40, # 50, MA-7, 11, 11, 00, 220, MONARCH 800, manufactured by Cabot Corporation) , 900, MOGULLBLACKPEARLS 130 REGAL 330, 400, 660 R (R avenl 255, 100, 100, etc., manufactured by Columbia Power Corporation) It is also possible to mix other alkaline blues with the carbon black.

If it is yellowish, C. IP igment Y e 1 ο w-1,3,4,5,6 1 2, 1 3, 1 4, 1 5 1 6, 1 7, 1 8, 2 4 5 5,6 5, 73, 74, 81, 83, 87, 93, 94, 95, 97, 9810, 0101, 101, 104, 1108, 109, 1 1 0 1 1 3, 1 1 6, 1 1 7 1 2 0, 1 2 3, 1 2 8, 1 2 9, 1 3 3, 1 3 8 1 3 9, 1 4 7, 1 5 1 1 5 3, 1 5 4, 1 5 5, 1 5 6, 1 6 8, 1 6 9 1 7 0, 1 7 1, 1 7 2 1 7 3, C. IP igment "e 1 ο w — 1 2, 1 3, 1 4 1 7, 8 1, 9 5, 10 9

It is preferable to use 1 5 4.

If it is reddish, C. 1. Pigment Red — 1.2, 3, 4, 5, 6, 7, 8, 8, 9, 10, 12, 12, 14, 15, 15, 18, 17, 2 2, 2 3, 31, 37, 38, 41, 42, 48: 1, 48: 2, 48: 3, 48: 4, 49: 1, 49: 2 , 50: 1.52: 1, 52: 2, 53: 1, 54, 57: 1, 58:,

6 0: 1, 6 3 1, 6 3: 2, 6 4: 1, 6 5, 6 6, 6 7, 6 8, 8 1, 8 3, 8 8, 9 0 9 0: 1, 1 1 2 , 1 1 4, 1 1 5, 1 2 2, 1 2 3, 1 3 3 1 4 4, 1 4 6 1 4 7, 1 4 9, 1 5 0, 1 5 1, 1 6 6, 1 6 8 , 1 7 0,

1 7 1, 1 7 2 1 7 4, 1 7 5, 1 7 6, 1 7 7, 1 7 8, 1 7 9, 1 8 5,

1 8 7, 1 8 8 1 8 9, 1 9 0, 1 9 3, 1 9 4, 2 0 2, 2 0 8, 2 0 9, 2 1 4, 2 1 6 2 2 0, 2 2 1, 2 2 4.2 4 2, 2 4 3, 2 4 3: 1.24

2 4 6, 2 4 7 CP igme η t R ed 3 1, 4 8 3, 5 7: 1, 8 1, 1 2 2 are preferred.

C. I.Pigment Blue-1, 2, 9, 14, 15, 16, 17: 1, 19, 21, 22, 24, 25, 5 6, 60, B 1, 6 3.64 and C. I. Pigment B iue — 15 is preferred.

In addition, phthalocyanine screens, oil violets, methyl oranges, and methyl violets are used.

In addition, the coloring particles may be added with a polyester or a resin as a main component, such as polyethylene glycol or polypropylene glycol, for adjusting the softening point.

Further, a charge control agent, a wax, or the like may be added to the surface of the particles in the particles for controlling the load and improving the dispersibility.

To prepare the developer of the present invention, the resin and the coloring material are melt-kneaded by applying heat with a twin-screw extruder, a kneader, or the like, and the mixture is pulverized. By using a ball mill, vibrating mill, an attritor, etc. in a hydrocarbon-based insulating solvent together with additives such as wax, wax, etc. Dispersion conditions for obtaining a predetermined particle size and a distribution can be set.

As a method for measuring the average diameter of the present invention, the particle diameter was measured using a Shimadzu centrifugal sedimentation type particle size distribution analyzer SA-CP3.

The viscosity of the developer and the solvent was measured using a B-type viscometer.

In addition, as a method for measuring the content of normal paraffin, 1.0 g of a sample was refined into a 10 ml mess flask, and a D-mouth form (reagent grade, manufactured by Kishida Chemical Co., Ltd.) was used. In addition, the volume is fixed to 10 m 1. This solution was measured using J & W's DB-1 column and a gasket HP 589 SΠ (manufactured by Hyure Red Packard) to correspond to the sample. The content of normal paraffin was measured from the peak area of the peak.

For details of the method for measuring the ultraviolet absorbance at a wavelength of 260 to 350 nm of an extract obtained by extracting a hydrocarbon solvent with dimethyl sulfoxide, see 25 mL of a hydrocarbon solvent, and The UV absorbance at a wavelength of 260 to 3δ0 nm of the extract extracted from oil using 5 ml of dimethyl sulfoxide for kettle was measured with an ultraviolet absorption measuring device.

Next, the image forming method of the present invention will be described. The developer of the present invention is used in a method of forming an electrostatic latent image on an electrostatic latent image carrier, and developing the latent image with a developer to form an image. ί 'A liquid developer is supplied to the electrostatic latent image on the image carrier via a developing roller, and the developed image is developed on an intermediate transfer body having a silicone rubber layer on the surface. It is preferably used in an image forming method in which a transfer image on the intermediate transfer body is re-transferred onto a transfer material after electrostatically transferring while being in contact with the transfer member.

In addition, in order to perform stable development with respect to temperature and process, colored particles composed of resin and a coloring material are converted into an insulative liquid on the electrostatic latent image on the electrostatic latent image carrier through a developing roller. A dispersed liquid developer is supplied and developed, and the developed image is electrostatically transferred while being in contact with an intermediate transfer body having a silicone rubber layer on the surface. An image forming method for re-transferring a transfer image on a photoreceptor onto a material to be transferred, wherein the liquid developer is mechanically or aerobically removed from the electrostatic latent image carrier to remove an insulative liquid. As a result, the solid content of the liquid developer on the electrostatic latent image carrier before being electrostatically transferred to the intermediate tiling object is insulated so as to have a solid content of 10 to 30 wt%. In the image forming method for removing an ionic liquid, the difference between the kinematic viscosity of the liquid developer at 10 and the value at 50 is 4 cs 4 or less. Arbitrary image forming method comprising the this is preferred.

Here, if the difference between the kinetic viscosity of the liquid developer at 10 ° C and the value at 50 ° C exceeds 4 cst, the difference before the transfer to the electrostatic β3 on the intermediate transfer body is obtained. When the solid content S of the liquid developer on the electrostatic latent image carrier deviates from the range of 10 to 3 O wt%, the image quality deteriorates, such as the image flowing in the printing direction. Can be seen.

In addition, in order to perform stable development with respect to temperature and process, a liquid developer is supplied to the electrostatic latent image on the electrostatic latent image carrier through a developing port and developed. After the obtained image is electrostatically transferred while being in contact with an intermediate transfer member having a silicone rubber layer on the surface, the transfer image on the intermediate transfer member is re-transferred onto a transfer material, and then In an image forming method having a liquid removing means for removing a solvent absorbed or solvated in the silicone rubber layer of the intermediate transfer member, the insulating liquid is a hydrocarbon solvent, An image forming method characterized by having a dry point of 280 ° C. or less and an initial boiling point of 180 ° C. or more is preferred.

If the dry point in distillation exceeds 280 ° C, the intermediate transfer — It becomes difficult to remove the solvent absorbed or solvated in the rubber layer, and the equipment needs to be enlarged. Furthermore, if the solvent is accumulated in the silicone rubber, the peeling force of the paper from the intermediate transfer member is increased, and problems such as paper jam occur.

More preferably, a liquid developing agent is supplied to the electrostatic latent image on the electrostatic latent image carrier through a developing roller, and a developed image obtained by development is brought into contact with the intermediate transfer member. A full-color image is formed on the intermediate transfer body by repeating the process of electrostatically transferring while transferring, and the full-color image on the intermediate transfer body is re-transferred onto the transfer material. It is preferably used for an image forming method that performs the following.

Here, contact with the intermediate transfer member means that the intermediate transfer member and the static latent image carrier are in contact with each other at two or more points without being developed with the liquid developer. In the process of actually developing and transferring with a liquid developer, the intermediate transfer member and the electrostatic latent image carrier are considered to be in contact with each other via the toner image.

The intermediate transfer member of the present invention has a silicone rubber on the surface of a highly heat-resistant rubber such as fluoro rubber via an adhesive layer, a sponge layer on a cloth, a rubber A material obtained by sequentially laminating silicone rubber is used.

The transfer material referred to in the present invention is not limited as long as it can be printed normally, such as paper, plastic film, metal, cloth, and board.

Example 1

Rosin-modified maleic acid resin (Arakawa Chemical's FGM-310, acid value of 108, softening point of 120 ° C,) 150 g, power black (MOGUL-L) After premixing 400 g of polyethylene glycol (PEG 600, manufactured by Sanyo Kasei Co., Ltd.) with a mixer, the mixture was melt-kneaded using a twin-screw extruder. Lead volume 2 kg / hr, temperature 100). After cooling the obtained melt-kneaded material, coarse powder having a particle diameter of about 50 m was obtained using a sample mill. 200 g of this coarse powder and 110 g of an acrylic polymer-based charge control agent solution (produced by the method described in Example XI of U.S. Pat. , Solid content 14 wt%), carnauba wax 15 g, and petroleum hydrocarbon solvent NP-HCS (Mitsui Texaco Chemical: Volume resistivity: 10 ' ^e Q' cm or more The initial boiling point is 220, the dry point is 260, the normal paraffin content is 98.7 wt%, and the wavelength of the oil effluent obtained by extracting the hydrocarbon solvent with dimethyl sulfoxide is 260. ~ 350 nm UV absorbance peak value 0.04 (wavelength 260 nm)) 1 250 g) and pulverize with a vibrating mill for 5 hours to obtain an average particle size of 1. 5 m of liquid toner was obtained. This stock solution was diluted with the agent NP-HCS to a solid content of 2 wt% S to prepare a developer.

In this development, the kinematic viscosity at 20 ° C. was 2.9 cst, and the difference between the kinematic viscosities at 50 ° C. and 10 was 2.05 cst.

At room temperature of 20 ° C, using the Se drum as a photoconductor, developing with the thus obtained developer at a linear speed of the photoconductor of 120 mm / sec using a developing port Then, the toner image formed on the photosensitive body is transferred onto an intermediate transfer body having silicone rubber attached on a drum on the outermost layer, and the toner image on the intermediate transfer body is erased by an error. When a 20 kg linear pressure was applied to the paper and the transfer was performed at a linear velocity of 40 mm / se at a pressure roller temperature of 200 ° C and a linear velocity of 40 mm / se, the print density without white background stain 1.3 1 image was obtained. Further, after the metal transfer was performed on the paper, the metal porter was brought into contact with the intermediate transfer member, thereby removing the solvent absorbed or solvated into the silicone rubber layer.

Also, when the temperature was raised to 30 ° C and the printing was repeated, and the temperature of the photoreceptor reached 40, printing was performed in the same manner. 4 1 images were obtained. Furthermore, when these prints were examined under magnification with a microscope, it was found that there was no dot tailing, and that a good image was obtained with a fine line of 30 m with no smoothness. found, also _c was divide and a large change is not this printed matter due to the temperature variation of铙only by 2 0 0 sheets but print density printing was performed also pressed within 0.2, good printed product Was obtained with good reproducibility, and no problems such as paper jams occurred.

Example 2

Printing was performed in the same manner as in Example 1 except that the developer of Example 1 was provided with a squeeze roller rotating in the opposite direction and a charger as a means for removing the developer on the photoconductor. Was.

Here, the printer is stopped during printing to determine the solid content of the developer on the latent image carrier before electrostatically transferred to the intermediate transfer body, and the toner on the photosensitive body before transfer is transferred. The degree of solids content was measured by weight change before and after drying, and it was 21.3 wt%. I got it.

As a result, an image having a print quality of 1.28 without white background stain was obtained. In addition, when these prints were examined under magnification with a microscope, good images without dot tailing and smooth 30 m fine lines were obtained without roughness. This proved that there was no significant change in the printed matter due to the temperature.

Further, printing of 200 sheets was performed continuously, but the fluctuation of the printing density was suppressed within 0.13, and a good printed matter was obtained with good reproducibility.

Example 3

Liquid toner was used in the same manner as in Example 1 by using 400 g of C.I.Pigment Yellow—13 (Seikafast Ye1low2600, manufactured by Dainichi Seika) instead of carbon black. At the time of preparation, a yellow toner with an average diameter of 1.1 m was obtained.

Liquid in the same manner as in Example 1 using 400 g of C.I.Pigment Red—57: 1 (Seikafast Carmine 6B14.776, manufactured by Dainichi Seika) instead of carbon black When the toner was prepared, a magenta toner having an average particle diameter of 1.4 m was obtained.

Liquid toner in the same manner as in Example 1 using C.I.Pigment Blue — 15 (Chromofine B 1 ue 5 187 87 manufactured by Dainichi Seika) instead of Riki Bon Black As a result, cyan toner having an average particle diameter of 0.8 / m was obtained.

At room temperature of 20 ° C, the Se drum is used as the photoconductor, and the developing roller of the four-color developer thus obtained is used at a linear speed of the photoconductor of 120 mm / sec. Yellow, magenta, cyan, and black toner are sequentially transferred for each color onto an intermediate transfer body with silicone rubber affixed to the drum on the outermost layer. When a full-color image is formed on the intermediate transfer member, the full-color image is applied to art paper at a linear pressure of 20 kg, and the temperature of the pressure port is 200 ° C. Transcription was performed at a linear speed of 40 mm / sec. As a result, the yellow print intensity was 1.3, the magenta print intensity was 1.3, the cyan print intensity was 1.5, and the black print intensity was 1.4. A good image without white background stain was obtained. In addition, as a result of continuous printing of 500 sheets, the printing It was also found that the color was suppressed within 0.2, and that the overlaid color was reproduced well. Example 4

Rosin modified maleic resin (Arakawa Chemical's FGM — 310, acid value 108, softening point 120 ° C, 154 g) 150g black (MOGUL — L) After premixing 400 g of polyethylene glycol (PEGS 0000, Sanyo Kasei Co., Ltd.) of 60 g, with a mixer, the mixture was melt-kneaded using a twin-screw extruder. (Load 2 kg / hr, temperature 100 ° C). After cooling the obtained melt-kneaded material, coarse powder having a particle diameter of about 50 m was obtained using a sample gel. 200 g of this coarse powder and 110 g of an acryl-based polymer-type charge control agent solution (according to the method described in Example XI of U.S. Pat. Manufactured, solid content: 14 wt%), carnapa's wax: 15 g, and petroleum hydrocarbon solvent having the following properties: ' ⁶ Ωcm or more, initial boiling point 2 25, dry point 2 4 2, no-soremal parafin 99.8 wt%, number of power in no-marmalparafin 1 2, 1 Ratio of 3 and 14 99.9 wt Hydrocarbon solvent extracted with dimethyl sulfoxide The peak value of ultraviolet absorbance at wavelength 260-350 nm 0.03 (wavelength 26 0 nm))) and mixed with a vibration mill for 5 hours to obtain a liquid toner having an average diameter of 1.5 μππι. This stock solution was diluted with the solvent JWS 8947 so as to have a solid content of 2 wt%, and used as a developer.

This developer had a kinematic viscosity at 20 ° C. of 2.8 cst and a difference between the kinematic viscosities of 50 and 10 1.9 cst.

Printing was performed in the same manner as in Example I using this developer, and as a result, an image with a printing portability of 1.35 having no white background stain was obtained.

In addition, when the room temperature was raised to 30 ° C and printing was repeated, and the temperature of the photoconductor reached 40 ° C, the same printing was performed. Two images were obtained. In addition, when these prints were examined under magnification with a microscope, it was confirmed that there was no dot tailing, and that a 30-m-long pongee line had a good image without any roughening. It was found that there was no significant change in the printed matter due to the temperature.

Continuous printing was performed on 200 sheets, but fluctuations in print density were also suppressed within 0.16. Good printed matter was obtained with good reproducibility.

Comparative Example 1

In the same manner as in Example 1, when a liquid toner was prepared using Christ-152 (manufactured by Soseki Oil Co., Ltd.) in place of NP-HCS, A black toner with a difference in kinematic viscosity of 4. δc¾t and an average diameter of 1. was obtained.

Using this toner, printing was performed in the same manner as in Example 1 except that the linear velocity of the pressure roller was 10 mm / sec, and an image with a printing degree of 0.85 was obtained at room temperature 20. When printing was repeated and printing was performed in a state where the temperature of the phosphor reached 40 °, an image with a printing port of 1.23 was obtained. It turned out that the dependence of the printing S degree was large.

Comparative Example 2

In the same manner as in Example 1, when a liquid toner (a product of Witco) was used in place of NP-HCS to prepare a liquid toner, the kinematic viscosity at 20 ° C was 5.4. cs, a black toner having an average particle size of 1 was obtained.

Using this toner, printing was performed in the same manner as in Example 1, but at room temperature of 20 and the printing intensity was 0.9, which was lower than that in Example 1, and in order to obtain the same printing portness as in Example 1. In this case, it was necessary to reduce the linear velocity of the photoconductor to 80 mm / sec, and the printing speed was reduced. Comparative Example 3

In the same manner as in Example 1, liquid toner was prepared using Nisseki Isosol 200 (manufactured by Nippon Petrochemical Co.) instead of NP-HCS. A black toner having a kinematic viscosity of 0.73 cst and an average particle size of 2 was obtained.

Using this toner, printing was performed in the same manner as in Example 1. However, a white background stain having a printing temperature of 0.015 occurred, and a good printed matter could not be obtained. Industrial applicability

Since the developer of the present invention has a small difference in developability due to temperature and process fluctuations, a stable printed matter can be obtained at high speed.

Claims

The scope of the claims

1. In a developer in which colored particles composed of resin and colorant are dispersed in an inexpensive liquid, the kinematic viscosity of the developer at 10 ° C and the value at 50 ° C A developer having a difference of 4 cst or less and a kinematic viscosity at 20 ° C of 1 cst or more and 5 cst or less.

2. In a developer obtained by dispersing a colored liquid composed of a resin and a colorant in a non-volatile liquid, the insulating liquid is a hydrocarbon solvent, and the dry point of the distillation is 2 points. 2. The developer according to claim 1, wherein the developer has an initial boiling point of 180 or more.

3. The insoluble liquid is a hydrocarbon solvent, the dry point of which is less than 270 in distillation, and the initial boiling point is more than 200 ° C. The developer described in 2

4. The developing method according to claim 1, wherein the insulating liquid is a hydrocarbon solvent, and a normal paraffin content in the hydrocarbon solvent accounts for 70 wt% or more. Agent.

5. 80% by weight or more of the normal paraffin components of the isocratic liquid are composed of carbon atoms of 12, 13 and 14; The developer described.

6. The insulating liquid is a hydrocarbon-based solvent, and the extract obtained by extracting the hydrocarbon-based solvent with dimethyl sulfoxide has an ultraviolet absorbance of 0.1 at a wavelength of 260-350 nm. The developer according to claim 1, wherein the developer is:

7. A developer is supplied to the electrostatic latent image on the electrostatic latent image carrier, and the head image obtained by the development is electrostatically transferred while being in contact with the intermediate transfer body having a silicone rubber layer on the surface. The developer according to claim 1, which is used in an image forming method of retransferring a transfer image on the intermediate transfer member onto a material to be transferred after the transfer.

8. A liquid developer is supplied to the electrostatic image on the electrostatic latent image carrier, and the developed image is electrostatically applied while contacting the developed image with an intermediate transfer member having a silicone rubber layer on the surface. And transferring the transferred image on the intermediate transfer member onto a transfer receiving material after transferring the liquid developer onto the electrostatic latent image carrier by mechanically or electrically. Eliminates persistent liquids As a result, the solid content of the liquid developer on the latent image carrier before electrostatic transfer to the intermediate transfer member is indispensable so as to have a solid content of 10 to 30 wt%. An image forming method for removing a liquid, wherein a difference between a value at a temperature of 10 ° C and a value at a temperature of 50 ° C of a liquid developer is not more than 4 cst. Forming method.

9. Quiet! : A liquid developer is supplied to the electrostatic latent image on the latent image carrier, and the developed image is developed. Electrostatic contact with the intermediate transfer body having a silicone rubber layer on the surface After the transfer, the transfer image on the intermediate transfer body is re-transferred onto the material to be transferred, and then the solvent is absorbed into the silicone rubber layer of the intermediate transfer body or the solvent is removed to remove the solvent. In the image forming method, the insulating liquid is a hydrocarbon solvent, the dry point in the distillation is 280 ° C or less, and the initial boiling point is 180 ° C or more. Characteristic image forming method.