JPH0278593A - Powder ink and printer - Google Patents

Abstract

PURPOSE:To stabilize a printing quality by providing a layer containing a dispersible improver between a core mainly composed of a wax and an outer shell mainly composed of a resin. CONSTITUTION:A layer containing a dispersible improver is provided between a core mainly composed of a wax and an outer shell mainly composed of a resin. As a wax compound 1 as a main component of the core, a vegetable natural wax, an animal natural wax, a synthetic wax, and the like are used. As a coloring material 2, carbon blacks and pigments or dyes can be used. As magnetic powder 3, fine powder of a magnetic material, such as ferrite, magnetite, and iron, is used. As a resin 4, an acrylic resin, a styrene resin, a butyral resin, a nylon resin, and the copolymer or crosslinked material of the aforesaid resins can be used. As the dispersible improver, polyphosphates or silicates of inorganic series, anions or cations of organic series, and nonionic water-soluble polymers of polymer series can be used. In this manner, the core and the outer shell are made easily compatible when the powder ink is melted so as to form a uniform ink sheet.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a printing apparatus having a step of forming an image by a thermal transfer printing method and a step of recycling an ink sheet using electrostatic force. Furthermore, patent application No. 63-36113
, concerning improvements in Japanese Patent Application No. 63-36115.

[Prior Art] Conventionally, as a thermal transfer printing method, a thermal head is pressed against an ink sheet formed with ink mainly composed of wax and a coloring material, and the image area is heated and melted, and the molten ink is transferred onto a recording medium. A commonly used method is to transfer and print.

In addition, as a thermal transfer printing device that recycles and uses an ink sheet, a printing device that has a step of forming an image by a thermal transfer printing method and a step of regenerating the ink sheet using electrostatic force is disclosed in Japanese Patent Application No. 63-36113. As a method for recycling ink sheets, Japanese Patent Application No. 63-36115 and the like have been proposed.

[Problem to be solved by the invention] However, the powder ink used in the conventional method of recycling ink sheets using electrostatic force has an inner core mainly composed of wax and an outer shell mainly composed of resin. However, in the process of melting the powder ink to form an ink sheet, the compatibility between the inner core and the outer shell was poor, so it was marked J! i! 1. There was a problem that the quality was not stable.

The present invention is intended to solve these problems.The purpose of the present invention is that when the powder ink is melted, the inner core and outer shell are easily compatible with each other to form a uniform ink layer. To provide a printing device with stable printing quality using an ink sheet.

[Means for Solving the Problems] The printing apparatus of the present invention uses powder used in an image forming method that includes a step of forming an image using a thermal transfer printing method and a step of recycling an ink sheet using electrostatic force. The ink is characterized by having a layer containing a dispersibility improver between an inner core mainly composed of wax and an outer shell mainly composed of resin.

Furthermore, it is characterized in that an image is formed and printed using this powder ink.

[Function] According to the above configuration of the present invention, in the step of printing by a thermal transfer printing method and subsequently supplying powder ink to the printed portion peeled off by printing to regenerate the ink layer, the powder ink is transferred to the heat roller. When heated, it melts and forms an ink sheet. The powder ink used here has an inner core mainly composed of wax, which is a component of the ink sheet, and an outer shell mainly composed of resin formed on the surface of the inner core to improve fluidity as a powder. It consists of Furthermore, the inner core is filled with a coloring material such as carbon black or magnetic powder, and the outer shell is filled with carbon black or the like.

Since the wax of the inner core component and the resin of the outer shell component are compatible, they can be melted and mixed by heating with a heat roller to form a uniform phase. On the other hand, since waxes, resins, coloring materials, and magnetic powders have little compatibility, adding a dispersibility improver enables uniform dispersion during heating. A unique ink layer can be formed. Furthermore, by using this ink sheet, a printing device with stable printing quality can be obtained.

The details of the present invention will be shown below with reference to Examples.

[Example] Figure 1 is a cross-sectional view of the powder ink of the present invention. The waxy compound 1, which is the main component of the inner core, includes natural vegetable waxes such as candelilla wax, carnauba wax, and rice wax, and beeswax. , animal-based natural waxes such as lanolin, mineral-based natural waxes such as montan wax and osikelite, paraffin wax, microcrystalline wax, natural petroleum waxes such as petrolatum, synthetic hydrocarbon waxes such as polyethylene wax and Fischer-Tropsch wax, and montan waxes.・) Modified waxes such as wax derivatives and paraffin wax derivatives, hydrogenated waxes such as hydrogenated castor oil and hydrogenated castor oil derivatives, and synthetic waxes such as fatty acids, acid amides, esters, and ketones are used, and these waxes may be used alone or in combination. It can be used as

Coloring materials 2 include carbon blacks such as furnace black, lamp black, and acetylene black for black colors, benzidine yellow and disazo yellow for yellow colors, and Carmen 6B, Lake Red C, pigment scarlet, and quinacridone for blue colors. Facial dyes such as phthalocyanine blue and ink-threne blue are used as such.

As the magnetic powder 3, fine powder of a magnetic material such as ferrite, magnetite, iron, chromium, nickel, etc. is used. This magnetic powder is added only when magnetic brush development is used.

Resin 4 is for binding wax and is made of polyacrylate,
Acrylic resin such as polymethacrylate, polystyrene,
Styrene resins such as poly-1-methylstyrene, butyral resins, polyvinyl chloride, polyvinylidene chloride, polyvinyl fluoride, polyvinylidene fluoride, polyester resins, polycarbonate resins, cellulose resins, polyarylate resins, polyethylene resins, vinyl acetate resins, and It is also possible to add thermoplastic resins such as these copolymers, and plasticizers such as phthalate esters, adipate esters, sebacate esters, phosphate esters, and modified epoxies. Furthermore, thermosetting resins such as epoxy resins, urethane resins, phenolic resins, melamine resins, urea resins, silicone resins, and alkyd resins, polyvinyl alcohol, polyallyl alcohol, polybenzyl alcohol, poly-2-hydroxyethyl methacrylate, and polyvinylpyrrolidone , polyvinylpyridine, polyvinylamine, polyallylamine, polyvinyl acrylic acid, polyvinyl methacrylic acid, polyvinyl sulfate, polylactic acid, casein, hydroxypropylcellulose, starch, gum arabic, polyglutamic acid,
Polyaspartic acid, nylon resin, and copolymers and crosslinked products of these resins can be used. This binding resin may or may not be added depending on the type of wax.

As a method for producing the inner core 5, a method known as a method for producing toner for electrophotography can be applied, and the inner core 5 is produced by melting and kneading the raw materials for the inner core components 1 to 4, pulverizing, and classifying.

Alternatively, the molten mixture can also be produced by a spray drying method.

The dispersibility improver layer 6 may be formed using a dispersion improver alone or together with a binder such as a resin.As an inorganic dispersion improver, a polyester such as tetrasodium birophosphate or sodium triphosphate may be used. phosphates, silicates such as sodium metasilicate, sodium disilicate,
As organic systems, alkyl polyether sulfates, alkylaryl sulfonates, alkylbenzene sulfonates, alkylnaphthalene sulfonic acids, dialkyl sulfosuccinates, higher alcohol sulfonates, fatty acid amide derivative sulfuric esters, polyethylene glycol alkyl allyl ether sulfonates, etc. Anions, cations such as alkylpyridinium chloride and trimethylstearylammonium chloride, nonions such as alkylphenol polyethylene ether, dialkyl succinate, sorbitan alkylate, and polyoxyethylene alkylphenol ether, and polymers such as polyacrylate derivatives and polyesters. methacrylate derivatives,
Polycarboxylic acid salts such as maleic anhydride copolymers, condensed naphthalene sulfonic acids, polyvinylpyrrolidone, nonionic water-soluble polymers such as polyether derivatives alone,
Alternatively, they can be used in combination. As the binding resin, the same resin as the resin 4 for the inner core can be used.

The outer shell 9, which is mainly composed of resin, is made of a coloring material 7 and a resin 8, both of which are combined with the coloring material 2 used in the inner core 5.
and resins similar to resin 4 can be used.

The dispersibility improver layer 6 and the outer shell 9 are produced by using microencapsulation methods such as spray drying, topochemical reaction, mechanochemical reaction, surface precipitation, and interfacial reaction. be done.

FIG. 2 shows an image forming method for a printing device, which includes a step of forming an image by a thermal transfer printing method using the powder ink of the present invention, and a step of recycling an ink sheet using electrostatic force.

In the step of forming an image by a thermal transfer printing method, an ink sheet 13 having an ink layer 12 on an insulating support 11 moves in the direction of an arrow 14, and a thermal head 15 moves the ink sheet 13 onto a recording medium 17 which advances in the direction of an arrow 16. is transferred and an image is formed on the recording medium 17.
By forming the image, an ink layer peeling portion 18 and an ink layer adhering portion 19 are formed on the ink sheet 13 . Subsequently, in the step of recycling the ink sheet, powder ink 21 is applied to the electrode 20 placed in contact with the insulating support 12 of the ink sheet 13 and the opposite side of the electrode 20 with the ink sheet 13 in between. A conductive roller 22 that is sequentially supplied upward is arranged, and a bias voltage is applied between the electrode 20 and the conductive roller 22 by a power source 23 to supply powder ink 2.
1 onto the ink sheet 13. Ink sheet 13
The powder ink 21 that has come into contact with the ink layer peeling part 18 of the ink layer peeling part 18 exhibits insulation properties,
An amount of charge proportional to the product of the capacitance and the bias voltage is injected into the insulating support 11 by electrostatic force. However, the ink layer 12 and the powder ink 21 that have come into contact with the ink layer adhering portion 19 of the ink sheet 13 and the powder ink 21 that has adhered to the insulating support 11 are conductive because the ink layer 12 and the powder ink 21 are conductive. The powder ink 21 that is replenished only to the ink layer peeling portion 18 of the ink sheet 13 is transferred onto the insulating support 11 by the heat roller 24 and the support roller 25. It is fixed, becomes an ink layer 12, and an ink sheet 13
is played. As the insulating support of the ink sheet used here, a resin film such as polyethylene terephthalate, polyaramid, polyimide, etc. can be used, and as the thermal head 15, in addition to the head used in the fusion heat transfer method, etc. A stylus head used in can also be used, and in the case of an electrically conductive thermal transfer method, an electrically conductive layer or the like is formed on the opposite side of the ink layer across the ink sheet.

As the recording medium 17, a tOHP sheet or the like is normally used. Further, as the conductive roller 22 that conveys the powder ink, a magnetic brush development method, which is known in the electrophotographic method,
A method such as a contact development method can be applied, and a heat roller 24,
For the support roller 25, a heat roll fixing method, a flash fixing method, etc., which are also known in the electrophotographic method, can be applied.

[Example 1] As the inner core of powder ink, paraffin wax 20 wt% carnauba wax 20 wt% ethylene/vinyl acetate copolymer 30 wt% carbon black 5 wt% were melt-mixed and the particle size was 12 μm.
m particles were produced.

As a dispersibility improver layer, 5 wt % polyvinylpyrrolidone and 5 wt % polyethylene glycol were formed by a spray drying method.

A powder ink was prepared by externally adding 10 wt% of acrylic resin and 5 wt% of carbon black as an outer shell by a spray drying method. A printing test was conducted using this powder ink by forming an image and recycling an ink sheet using the method shown in FIG. Note that a 6 μm thick polyaramid film was used as an insulating support for the ink sheet.

Further, as an image forming method, a thin line of 1 mm was written in parallel to the moving direction of the ink sheet, and the writing part was moved in the horizontal direction for each cycle, and changes in the number of cycles and print quality were observed. The results are shown in Table 1.

Table 1 Print density: Optical temperature of image on recording medium Soakness of ink layer adhered area: Optical temperature of density of ink layer peeled area Ink sheet made with the powder ink of the present invention as shown in Table 1 A printing device with sufficient printing density up to 50 cycles and stable printing quality was obtained.

[Comparative Example 1] As the inner core of powder ink, paraffin wax 25 wt% carnauba wax 25 wt% ethylene.
Vinyl acetate copolymer 30wt% carbon black
Melt and mix 5wt%, particle size 12μm
particles were prepared.

A powder ink was prepared by externally adding 10 wt% of acrylic resin and 5 wt% of carbon black as an outer shell by a spray drying method. A printing test was conducted using this powder ink in the same manner as in Example 1. The results are shown in Table 2.

Table 2 Print Density 2 Optical density of image on recording medium Concentration of ink layer peeled part: Optical soaking degree of ink layer peeled part density As shown in Table 2, for powder ink without a dispersion improver layer, the number of cycles There are large changes in print density due to printing, and print quality is unstable.

[Example 2] As the inner core of powder ink, microcrystalline wax 15 wt% oxidized polyethylene wax 15 wt% ethylene/vinyl acetate copolymer 10 wt% carbon black
4 wt% magnetite
33 wt% was melt-kneaded to produce particles with a particle size of 10 μm.

As a dispersibility improver layer, 7 wt % of polyethylene glycol and 5 wt % of styrene maleic anhydride copolymer were formed by a spray drying method.

A powder ink was prepared by externally adding 7 wt% of styrene-acrylic copolymer and 4 wt% of carbon black as an outer shell by a spray drying method. A printing test was conducted using this powder ink by forming an image and recycling an ink sheet using the method shown in FIG. Note that a 4 μm thick polyethylene terephthalate film was used as an insulating support for the ink sheet. Further, as an image forming method, a thin line of 1 mm was written in parallel to the moving direction of the ink sheet, and the writing part was moved in the horizontal direction for each cycle, and changes in the number of cycles and print quality were observed. The results are shown in Table 3.

Table 3 Printing density: Optical temperature of image on recording medium Temperature at ink layer peeling part: Optical soaking degree of temperature at ink layer peeling part Ink sheet made with the powder ink of the present invention as shown in Table 3 A printing device with sufficient printing density up to 30 cycles and stable printing quality was obtained.

[Comparative Example 2] As the inner core of powder ink, microcrystalline wax 20wt% oxidized polyethylene wax 20wt% ethylene/vinyl acetate copolymer 10wt% carbon black
4wt% magnetite
35 wt% was melt-kneaded to produce particles with a particle size of 10 μm.

A powder ink was prepared by externally adding 7 wt% of styrene-acrylic copolymer and 4 wt% of carbon black as an outer shell by a spray drying method. A printing test was conducted using this powder ink in the same manner as in Example 2. The results are shown in Table 4.

Table 4 Print density: Optical temperature of image on recording medium Cleanliness of ink layer adhering area: Optical density of ink layer peeling area density As shown in Table 4, for powder ink without a dispersion improver layer, number of cycles There are large changes in print density due to printing, and print quality is unstable.

[Effects of the Invention] As described above, according to the present invention, a powder is used in an image forming method that includes a step of forming an image by a thermal transfer printing method and a step of recycling an ink sheet using electrostatic force. In the ink, by having a layer containing a dispersion improver between the inner core mainly composed of wax and the outer shell mainly composed of resin, when the powder ink is melted, the inner core and the outer shell can easily be mixed with each other. Melts and forms a uniform ink sheet. Furthermore, using this ink sheet, it has become possible to provide a printing device with stable printing quality.

The powder ink and printing device of the present invention can be applied to devices using an image forming method that includes a step of forming an image using a thermal transfer method and a step of recycling and using an ink sheet, such as a printer, a copying machine, and a facsimile machine. It can be applied to a wide range of other things.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of the powder ink of the present invention. 1, Waxy compound 2, Coloring material 3, Magnetic powder 4, Resin 5, Inner core 6, Dispersibility improver layer 7, Coloring material 8, Resin 9, Outer shell Fig. 2 uses the powder ink of the present invention. FIG. 3 is a diagram illustrating an image forming method of a printing apparatus, which also includes a step of forming an image by a thermal transfer printing method and a step of regenerating an ink sheet using electrostatic force. 116 Insulating support 12, ink layer 13, ink sheet 14, moving direction 15, thermal head 16, moving direction 17, recording medium 18, ink layer peeling section 19, ink layer adhering section 20, electrode 21, powder ink 22 , conductive roller 23, power supply 24, heat roller 25, support roller and above Applicant: Seiko Epson Co., Ltd. Agent Patent attorney: Kizobe Suzuki (1 person) Figure 2

Claims (2)

[Claims] (1) Powder ink used in an image forming method that includes a step of forming an image by a thermal transfer printing method and a step of recycling an ink sheet using electrostatic force, has an inner core mainly composed of wax and a resin. A powder ink characterized by having a layer containing a dispersibility improver between an outer shell having a main component. (2) In a printing device that consists of a step of forming an image using a thermal transfer printing method and a step of regenerating an ink sheet using electrostatic force, there is a gap between an inner core mainly composed of wax and an outer shell mainly composed of resin. A printing device characterized by using a powder ink having a layer containing a dispersibility improver.