JPH04107175A - Image forming apparatus - Google Patents

Abstract

PURPOSE:To suppress the deterioration of an ink sheet by forming a back layer constituted of a substance having an m.p. of 300 deg.C or higher or having no substantial m.p. to the rear of the ink sheet. CONSTITUTION:An ink sheet 1 is fed in the direction shown by an arrow 20 by a feed means. An image forming means composed of a writing head capable of transferring an ink layer by heat such as a stylus head forms an images on the medium 5 moving in the direction by an arrow 21. Since a back layer 2 is formed to the rear of the ink sheet, the thermal or mechanical deterioration of the ink sheet accompanying the formation of an image can be suppressed to the min. The back layer 2 is constituted of a substance having an m.p. of 300 deg.C or higher or having no substantial m.p. and composed of a thermosetting resin such as a phenol resin, a thermoplastic resin such as polyamideimide, a treatment agent such as a silane coupling agent, an element such as Cu or the like or an alloy thereof, oxide such as SiO2 or a composite or mixture of them.

Description

Detailed Description of the Invention [Industrial Application Field] The present invention provides an image forming method that has a means for forming an image by a thermal transfer method and a means for regenerating an ink sheet, and performs image formation while sequentially regenerating the ink sheet. The present invention relates to a forming device.

[Prior Art] As an image forming apparatus that forms images using a thermal transfer method, a compact and highly reliable image forming apparatus that is equipped with various types of recording methods such as a melt transfer recording method and a sublimation dye transfer recording method has been proposed. It has been put into practical use.

Furthermore, in order to improve economic efficiency, studies have been made on methods for improving the effectiveness of ink sheet use, methods for dealing with rough paper, and the like.

As one method for improving the effectiveness of ink sheet use, the present inventors proposed an ink sheet recycling method and apparatus in Japanese Patent Application Laid-open No. 1-295876.

Images created using the ink sheet produced and recycled using the ink sheet recycling method and apparatus disclosed in Japanese Patent Application Laid-Open No. 1-295876 are of high recording quality and good quality, and have excellent repeatability. It was in good condition.

[Problems to be Solved by the Invention] Due to the heat generated by the thermal head, the surface temperature of the head heating element instantaneously rises to 300° C. or more, and the temperature of the ink sheet in contact with the heater also rises considerably. As image formation is repeated, deterioration of the ink sheet progresses, and in the worst case, serious defects may occur in image quality.

Therefore, the present invention is a further development of Japanese Patent Application Laid-Open No. 1-295876, and an object of the present invention is to provide an image forming apparatus that further extends the life of an ink sheet. Another object of the present invention is to provide an image forming apparatus that further improves the reproduction quality of ink sheets and the image quality.

[Means for Solving the Problems] An image forming apparatus of the present invention has a means for forming an image by a thermal transfer method and a means for regenerating an ink sheet.
It is characterized in that a back layer is formed of a substance that has a temperature of 0.degree. C. or higher or has no substantial melting point.

[Function] According to the above structure of the present invention, since the back layer is formed on the back side of the ink sheet, that is, on the side that contacts the thermal head, deterioration of the ink sheet due to heat can be avoided.

[Example code] Hereinafter, the present invention will be described in detail based on the drawings.

FIG. 1 is a schematic diagram showing an image forming apparatus according to the present invention.

The ink sheet 1 includes at least a back layer 2 as a component on the back side of the ink sheet 1, and also includes a dielectric layer 4 immediately below the conductive ink layer 3.

Note that the back side of the ink sheet refers to the side on which the ink layer is not formed and comes into contact with the thermal head, and
The ink sheet 1 may include other components. For example, a conductive layer may be formed between the dielectric layer 4 and the back layer 2.

Here, the back layer 2 is made of a material having a melting point of 300° C. or higher or having no substantial melting point. Note that the melting point is measured by the DSC method and refers to the transition temperature from solid to liquid (fluid). An example of the back layer 2 is shown below.

■Thermosetting resins such as phenolic resin, urea resin, melamine resin, allyl resin, furan resin, unsaturated polyester resin, epoxy resin, silicone resin, polyimide, polyurethane, etc.

■Thermoplastic resins such as polyamideimide, polyetheretherketone, and polyethersulfone.

■Treatment agents such as silane coupling agents, titanium coupling agents, aluminum coupling agents, and chromium coupling agents.

■Elements and alloys such as Cu, Au, Ni, Cr, and Si.

■SiO□, S i C%S i 3N4, NiS, C
Oxides, carbides, nitrides, sulfides, and inorganic salts such as aCO3.

Consists of single substances, complexes, and mixtures of substances selected from these ■～■.

The conductive ink 3 includes carbon black (e.g., furnace black, acetylene black), N oxide (e.g., ITO powder, Sn○2 powder), metal powder (e.g., Ag powder,
It contains at least one conductive agent such as Al powder), salt (e.g., quaternary ammonium salt), and tetraelectric resin (e.g., polyacetylene, polypyrrole), and has a volume resistivity of approximately 10 IOΩcm or less. Furthermore, if necessary, it contains a substance selected from the group of substances listed below.

1) Candelilla wax, carnauba wax, rice wax, beeswax, lanolin, montan wax, osichelite, paraffin wax, microcrystalline wax, berotratum, polyethylene wax, Fischer-Tropsch wax, montan wax derivative, paraffin wax derivative, hydrogenated castor oil, synthetic Waxes such as wax, higher fatty acids such as stearic acid and valmitic acid, polyolefins such as low molecular weight polyethylene, polyethylene oxide, and polypropylene, ethylene/acrylic acid copolymer, ethylene/acrylic acid ester copolymer, ethylene/acetic acid A single substance or a composite selected from olefin copolymers such as vinyl copolymers.

2) Acrylic resins such as polyacrylate and polymethacrylate, styrene resins such as polystyrene and poly-1-methylstyrene, butyral resins, polyvinyl chloride, polyvinylidene chloride, polyvinyl fluoride, polyvinylidene fluoride, polyester resins, polycarbonate resins, Simple substances, copolymers, and mixtures of resins selected from thermoplastic resins such as cellulose resins, polyarylate resins, and polyethylene resins.

3) Polyvinyl alcohol, polyallyl alcohol, polyvinyl and lolidone, polyvinylamine, polyallylamine, polyvinyl acrylic acid, polyvinyl methacrylic acid, polyvinyl sulfate, polylactic acid, casein, hydroxypropylcellulose, starch, gum arabic, polyglutamic acid, polyaspartic acid , simple substances, copolymers, and mixtures of resins selected from water-soluble resins such as nylon resins.

4) Resin selected from thermosetting resins such as epoxy resin, silicone resin, urethane resin, melamine resin, and alkyd resin.

5) Colorants such as black pigments (dyes and pigments) such as furnace black, lamp black, acetylene black, and nigrosine, cyan pigments such as copper phthalocyanine, magenta pigments such as Riki-min 6B, and yellow pigments such as disazo yellow.

6) Magnetic powder such as Fe30a, Fe2O3, Fe, Cr, Ni, etc.

7) Surfactants or dispersants such as metal soaps and polyethylene glycol.

8) Charge control agents such as electron-accepting organic complexes, chlorinated polyesters, nitrofnic acids, quaternary ammonium salts, and pyridinium salts.

9) Fillers such as talc.

10) Fluidity improvers such as SiO2 and TiO2.

The dielectric layer 4 only needs to have a volume resistivity of about 1012 Ωcm or more, and is made of, for example, a substance selected from the above substance group 2) or 4), an oxide, a nitride, a carbide, or the like. Alternatively, easily formed polymer films such as polyethylene terephthalate, polyphenylene sulfide, polyimide, polyamide, polyamideimide, etc. can also be used.

Note that when the dielectric layer 4 is made of a substance with a melting point of 300° C. or more or a substance that does not have a substantial melting point, the dielectric layer 4 exhibits the same effect as the back layer 2.

The ink sheet 1 is conveyed in the direction of arrow 20 by a conveying means (not shown). An image forming means 30 consisting of a writing head capable of thermally transferring an ink layer, such as a thermal head or a stylus head (current-carrying head), forms an image on the medium 5 moving in the direction of the arrow 21, where the back side of the ink sheet Since the back layer 2 is formed on the side, thermal or mechanical deterioration of the ink sheet accompanying image formation can be minimized.

A transferred portion 6b of the conductive ink layer 3 and an untransferred portion (adhered portion) 6a of the conductive ink layer 3 are formed on the ink sheet 1 after image formation.

back electrode 7, sleeve 8, conductive ink 9, power supply 10,
The ink sheet is regenerated by an ink sheet recycling means consisting of a means 11 for fixing the conductive ink onto the ink sheet, such as a heat roller or a heat pressure roller (in FIG. 1, a heat roller is adopted as the fixation means). The ink layer is regenerated.

Here, in the ink sheet recycling means, a back electrode 7 connected to a power source 10 and a fixing means 11 are in contact with the back layer 2 of the ink sheet, and an ink sheet is placed on the opposite side of the back electrode 7 and the ink sheet 1. A grounded sleeve 8 is placed at a predetermined distance from the sheet 1, and conductive ink 9 held by the sleeve 8 is conveyed through the space. When the voltage V is supplied from the power supply 10, the voltages V and g are applied to the back layer 2 of the ink sheet 1.
An amount of charge q proportional to the product of the capacitance of the electric layer 4 is injected,
Or induced. Along with this, charge -q is injected into the conductive ink 9 that has come into contact with the transferred portion 6b of the conductive ink layer, but the charge -q is injected into the conductive ink layer that has not been transferred 6a or
The conductive ink 9 that has come into contact with the conductive ink 9 merely serves as a path for the charge and does not retain the charge, therefore,
The conductive ink 9 can be attached only to the transfer portion 6b of the conductive ink layer by electrostatic force.

The ink sheet 1 to which the conductive ink 9 has adhered is fixed onto the ink sheet 1 by the fixing means 11 .

Here, the form of the conductive ink 9 can be any of powder ink, paste ink, molten/dissolved ink, and semi-molten/semi-molten ink, but preferably powder ink. Good ink.

(Figure 1 is illustrated using powdered ink.) The ink sheet 1 that has been subjected to image formation and ink sheet regeneration in this manner can be used for image formation again.

The ink sheet of the present invention was able to maintain the image quality of the first time without degrading the image quality of the formed image even after repeating image formation and ink sheet regeneration more than 2,000 times.

[Example 1] In order to examine the effect of the back layer, the back layer shown in Table 1 was formed to a thickness of 0.5 μm on the back of a 6 μm thick polyester film (dielectric layer 4), and ink sheets A to F were formed. Prepared. Note that Table 1 also shows the melting point of the back layer.

Image formation and ink sheet regeneration were repeated 2000 times on these ink sheets A to F using the image forming apparatus shown in FIG. In addition, paraffin wax 10wt% carnauba wax was used as the conductive ink.
40wt% ethylene vinyl acetate copolymer
A powder having a particle size of 15 μm and a volume resistivity of 104 Ωcm was used, which was prepared by encapsulating 5 wt% Fe20345 wt% as an inner core, encapsulating it with a polyester resin (thickness: 0.2 μm), and externally adding carbon black.

Regarding the 1st, 1000th, and 2000th images,
The recorded temperature and the sharpness of the thin line were evaluated, and the differences between the values compared to the first time were examined. The results are also shown in Table 1. In Table 1, the results are as follows: ■... Good (98-101%) O... Fair (95% or more) △... Slightly poor (85% or more) ×...defect (~85%), the ink sheet is S, the material of the back layer, the melting point are each X, Mp ('C), the recording temperature is ○D, the sharpness of the thin line is M
TF, 100th time, and 2000th time are each abbreviated as 1.2. Note that the symbol - in the column of back layer material indicates that no back layer is formed.

It turns out that it is possible to suppress the In particular, repeat 1
It can also be seen that the above-mentioned back layer is essential in order to perform the test more than 000 times.

Note that the present invention is not limited to this example.

From Table 1, Table 1 shows that if a back layer made of a substance with a melting point of 300°C or higher or a material with no substantial melting point is formed on the back side of the ink sheet, the image quality due to repeated use of the ink sheet will be reduced. [Effect of the Invention] As described above, the image forming apparatus according to the present invention has a means for forming an image by a thermal transfer method and a means for recycling an ink sheet. Since the back layer is formed of a substance having a melting point of 300° C. or higher or having no substantial melting point, deterioration of the ink sheet accompanying image formation can be suppressed.

Therefore, the life of the ink sheet can be extended, and running costs can be further reduced. Furthermore, the reproduction quality and image quality of the ink sheet were further improved.

From the above, the image forming apparatus of the present invention is particularly effective when applied to image forming apparatuses such as printers, video printers, facsimile machines, copying machines, and word processor output devices.

4,

[Brief explanation of drawings]

Figure 1 shows An image forming apparatus according to the present invention is shown. Schematic. stomach sheet back layer back electrode ・Conductive ink Image forming means Below Up

Claims (1)

[Claims] (1) In an image forming apparatus having a means for forming an image by a thermal transfer method and a means for recycling an ink sheet, the back side of the ink sheet is made from a substance with a melting point of 300° C. or more or a substance that does not have a substantial melting point. What is claimed is: 1. An image forming apparatus characterized in that a back layer consisting of: