JPH02164584A - Image forming method - Google Patents

Abstract

PURPOSE:To prevent the generation of background fog at the end part of a medium to be recorded by differentiating the quantity of the light and heat energies applied to the vicinities of the leading and rear end parts of the medium to be recorded from that applied to the other parts of said medium. CONSTITUTION:By making the quantity of the light and heat quantities applied to the parts, which are superposed on the recording start and finish vicinities of a medium to be recorded, of a transfer recording medium larger than usual quantity of light and heat energies, the transfer characteristics of a transfer recording layer is largely changed. Since the formation of an image to the transfer recording medium 1 and the transfer of said image to the medium to be recorded are successively performed, an image is well recorded even on the medium to be recorded relatively low in surface smoothness. Since the quantities of energies to be applied at the times of the start and finish of recording are increased, there is no possibility of background fog due to the insertion of recording paper in a transfer part 4 and an increase in pressure at the time of the discharge of the recording paper 8 from the transfer part 4 at all and a high contrast image can be obtained.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is applicable to printers, copying machines, facsimile machines, etc.
Regarding recording methods that can be used.

[Background Art] In recent years, with the rapid development of the information industry, various information processing systems have been developed, and recording devices suitable for each information processing system have also been developed.

One of the above-mentioned recording devices is a thermal transfer recording device. In this method, recording is performed on a recording paper using an ink ribbon made by coating a ribbon-shaped support with a heat-melt ink made by dispersing a colorant in a heat-melt binder.

That is, the ink ribbons are stacked so that their heat-melting ink layers are in contact with the recording paper, and the ink ribbon and the recording paper are conveyed between a thermal head and a platen, and the ink ribbon is transferred from the support side of the ink ribbon to the thermal head. By applying pulse-shaped heat according to the image signal and pressing the two together and transferring the melted ink to the recording paper, an ink image corresponding to the heat application is recorded on the recording paper. be.

The above recording apparatus has been widely used in recent years because it is small and lightweight, makes no noise, and can record on plain paper.

However, conventional thermal transfer recording devices are not without problems.

The reason is that in conventional thermal transfer recording devices, the transfer recording performance, that is, the image quality, is greatly affected by the surface smoothness of the recording paper.
Although good image recording is performed on recording paper with high smoothness, there is a possibility that the quality of image recording will deteriorate when recording paper with low smoothness is used.

Furthermore, when attempting to obtain a multicolor image with a conventional thermal transfer recording device, it is necessary to repeat transfer to overlap the colors. For this purpose, it is necessary to install multiple thermal heads or make complicated movements such as stopping and reversing the recording paper, which not only makes color misalignment unavoidable, but also makes the entire device large and complicated. There is a problem with this.

Therefore, the applicant used a photothermally sensitive material.

When thermal energy and light energy are applied, the reaction of the material rapidly progresses and the transfer characteristics change irreversibly.
We proposed a technology to form an image based on the difference in characteristics according to the image signal and transfer it to a recording medium (Japanese Patent Application Laid-Open No. 1983-1999).
No. 174195).

According to this technology, it is possible to record high-quality images even on recording media with low surface smoothness, and when applied to multicolor recording, it is possible to make complex movements on the recording medium. It is possible to obtain multi-colored images without any problems.

The transfer recording medium used in this image forming method has a transfer recording layer provided on a support, and the transfer recording layer contains at least a photopolymerization initiator and a compound having an unsaturated double bond, such as a monomer, oligomer or It contains a chemical form such as a polymer and a coloring agent. The viscosity of this transfer recording layer rapidly decreases at a softening temperature of 18 or higher.

In this image forming method, the transfer recording layer is uniformly irradiated with light corresponding to the absorption wavelength of the photopolymerization initiator contained in the transfer recording layer, and at the same time, a heating means such as a thermal head is used in accordance with the recorded information. is partially heated to a temperature of 13 or higher to form a transferred image in the transfer recording layer. That is, the viscosity of the portion heated to 13 or higher decreases rapidly, the diffusion viscosity of the photopolymerization initiator and the compound having an unsaturated double bond in the transfer recording layer increases, and the polymerization reaction rapidly progresses. On the other hand, in the non-heated part, the viscosity of the transfer recording layer does not decrease, so the photopolymerization initiator and the compound having an unsaturated double bond do not diffuse sufficiently, and the polymerization reaction occurs only partially. A transfer image is formed on the transfer recording layer due to this difference in polymerization reaction.

In this way, the transfer recording medium on which the transferred image has been formed is brought into pressure contact with the recording medium and heated to a predetermined temperature, for example, to a temperature of T or higher. The portion where only a partial occurrence of is transferred to the recording medium, and the polymerization reaction has progressed sufficiently in the heated part of the thermal head, so the adhesiveness corresponding to the recording medium is smaller than in the non-heated part. Therefore, it is not transferred to the recording medium.

As mentioned above, by light energy and thermal energy,
An image is formed on the recording medium.

In the above example, the softening temperature T3 of the transfer recording layer was used as the physical property value that governs the transfer characteristics and polymerization reaction amount of the transfer recording layer, but in addition to this, the glass softening point, melting temperature, etc. of the transfer recording layer are also used. It doesn't matter if you do.

[Problems to be Solved by the Invention] In the image formation described above, in the transfer step, the transfer recording medium on which the transferred image is formed and the recording medium are conveyed in a superimposed manner, and the transferred image is deposited on the recording medium. is transferred, and at this time the transfer is accelerated by applying heat and pressure. As the pressing means, two rollers that are pressed against each other are generally used. Now, the pressure exerted on the recording medium and the transfer recording medium by one inch from the time when the recording medium overlaps the transfer recording medium and enters between the two pressure-contact rollers until it finishes passing through is the pressure exerted by the two rollers. If the nip of the rollers is 2, the result will be roughly as shown in FIG.

Therefore, the pressure at both ends of the recording medium is higher than the other parts, which improves transferability, but this means that since this recording method uses negative recording, background fog is likely to occur at both ends of the recording medium. cause problems.

The present invention is a further development of the above-mentioned technology, and aims to provide an image forming method capable of obtaining a high-contrast image without background fog.

[Means for Solving the Problems] The present invention provides for transporting a transfer recording medium having a transfer recording layer whose transfer characteristics change when thermal energy and light energy are applied, and applying the light and the transfer recording medium to the transfer recording medium. A transfer image forming step of forming a transfer image by applying light and heat energy while applying at least one of heat energy in correspondence with recorded information, and superimposing the transfer recording medium and the recording medium. An image forming method comprising a transfer step of transferring the transferred image onto a recording medium,
An image forming method characterized in that the amounts of light and thermal energy applied are different at the start of recording, that is, near the leading edge of the recording medium, at the end of recording, that is, near the leading edge of the recording medium, and in other parts. be.

In the present invention, the transfer of the transfer recording layer is performed by increasing the amount of light and heat energy applied to the transfer recording medium in the vicinity of the transfer recording medium that overlaps both ends of the recording medium (near the start and end of recording) compared to the normal application amount. The characteristics can be made thicker (changed) to prevent background fog from occurring at the edges of the recording medium.

When applying light and thermal energy near the start and end of recording, both energy may be applied uniformly over a predetermined length regardless of the recorded information, or it may be applied only to a portion corresponding to the recorded information (background). It doesn't matter if you apply more energy than normal.

Also, places that give a larger amount of energy than usual are
It may be an area extending a predetermined length from the end of the recording medium to the inside of the recording medium, or an area extending a predetermined length at both positions corresponding to the end (outside and inside the recording medium). In either case, it is desirable that the length that applies a large amount of energy to the inner side of the end is equal to the nip length ε.

Furthermore, the amount of energy applied may be uniform within a section of length 2 from the end, or may be greater toward the end.

The transfer recording layer may be a continuous layer in which the transfer recording layer is continuously coated on the support, or the material of the transfer recording layer may be formed into a particle-like element body, and the transfer recording layer may be formed as a distribution layer of the particle element body. You can configure it. Further, the particulate element may be composed of microcapsules containing a photopolymerization initiator, a compound having an unsaturated double bond, and a coloring agent in the core material.

In addition, the 28 transfer layers are composed of particulate elements or microcapsules, and each element or microcapsule contains a coloring agent so as to have one of a plurality of color tones, and each particulate element By changing the sensitive wavelength range of the photopolymerization initiator contained in the body or each microcapsule in accordance with the color tone to be exhibited, it is possible to form a multicolor image.

The transfer recording layer constituting the transfer recording medium used in the image forming method of the present invention includes at least a photopolymerization initiator and a photothermally reactive material having the above characteristics (a monomer, oligomer or polymer having an unsaturated double bond). Contains and
Additives such as a binder, a thermal polymerization inhibitor, a plasticizer, a coloring agent, and a surface smoothing agent may be included as necessary.

Examples of the photopolymerization initiator include carbonyl compounds, halogen compounds, azo compounds, organic compounds, and aromatic ketones such as acetophenone, benzophenone, coumarin, xanthone, thioxanthone, chalcone, and styryl styryl ketone. and derivatives thereof/, diketones such as benzyl, acenafrenequinone, camphorquinone and derivatives thereof/, anthraquinone sulfonyl, chloride 7quinolinesulfonyl chloride, 2.4
．． Fake photopolymerization initiators include, but are not limited to, halogen compounds such as 6-tris(trichloromethyl)-s-triazine. It is preferably about 0.1 to 20 parts by weight based on A.

Furthermore, when performing multicolor recording using the image forming method of the present invention,
The transfer recording layer is composed of a minute image forming element, and the image forming element needs to have wavelength selectivity depending on the coloring material it contains. In other words, when the image recording layer is composed of image forming elements of n types of colors, the reaction speed changes rapidly with light of different wavelengths for each colored color, that is, with n types of different wavelengths. and a photopolymerization initiator to form a distribution layer of the image forming element.

The monomers, oligomers, and polymers having unsaturated double bonds include polyaddition reactions of polyisocyanates and alcohols and amines containing unsaturated double bonds (which may be reacted with polyols if necessary). Urethane acrylates or urethane methacrylates having urethane bonds synthesized by epoxy acrylates/or polyester acrylates synthesized by addition reaction of epoxy resin and acrylic acid or methacrylic acid, spin acrylates, polyether acrylates However, the present invention is not limited thereto.

In addition, other polymers have skeletons such as polyalkyl, polyether, polyester, and polyurethane in the main chain, and acrylic, methacrylic, cinnamoyl, cinnamylideneacetyl, furyl acryloyl, and silicone groups in the side chains. Examples include those into which polymerizable and crosslinkable reactive groups, such as esters of acid, are introduced, but the present invention is not limited thereto.

The monomers, oligomers, and polymers mentioned above are preferably semi-solid or solid at room temperature, but even if they are liquid, if they can be maintained in a semi-solid or solid state by mixing with the binder described below. No Matter 9 The above monomer, oligomer or polymer having an unsaturated double bond and the photopolymerization initiator may be used in combination with a binder.

As a binder, a monomer having an unsaturated double bond,
Any organic polymer that is compatible with the oligomer or polymer may be used. Examples of such organic polymers include polyacrylic acid alkyl esters such as polymethyl acrylate and polyethyl acrylate, polymethacrylic acid alkyl esters such as polymethyl methacrylate and polyethyl methacrylate, or methacrylic acid copolymers. , acrylic acid copolymers, maleic acid copolymers/or chlorinated polyolefins such as chlorinated polyethylene, chlorinated polypropylene,
Polyvinyl chloride, polyvinylidene chloride, polyacrylonitrile or copolymers thereof, as well as polyvinyl alkyl ether polyethylene, polypropylene, polystyrene.

Examples include polyamide, polyurethane, chlorinated rubber, cellulose derivatives, polyvinyl alcohol, polyvinylpyrrolidone, etc., but the present invention is not limited thereto. These binders may be used alone or
Two or more types may be mixed and used in an appropriate ratio. Further, the binder is not limited to compatible or incompatible waxes, and waxes may be used.

The colorant is a component that is included to form an optically recognizable image, and various pigments and dyes are used as appropriate. Examples of such pigments and dyes include carbon black, yellow lead, molybdenum red, inorganic pigments such as red red, Hansa yellow, benzine yellow, brilliant carmine 6B, lake red F5R, phthalocyanine blue,
Examples include organic pigments such as Victoria Blue Lake and Fast Sky Blue, and coloring agents such as leuco dyes and phthalocyanine dyes.

The amount of the colorant is preferably 0.1 to 30 parts by weight based on the total amount of the binder, photopolymerization initiator, monomer having an unsaturated double bond, olefin, and polymer.

The transfer recording layer described above may be a continuous M layer formed by dissolving it in a solvent and coating it on a support, or it may be a layer in which a large number of particulate image forming elements are distributed. It doesn't matter.

The thickness of the transfer recording layer is preferably 1 to 20 μm, particularly 3 to 20 μm.
10μ is preferred. When the transfer recording layer is composed of a distributed layer of particulate image-forming elements, the particle size of the elements is preferably from 1 to 20 μm, particularly preferably from 3 to 15 μm. Further, the particle size distribution of the element body is preferably ±50% or less with respect to the number average diameter,
In particular, ±20% or less is preferable.

The base material for supporting the transfer recording layer is not particularly limited, and any known support material can be used as is. Examples include polyester, polycarbonate, triacetylcellulose, nylon, polyimide, and the like.

〔Example〕

A transfer recording medium was produced by the following method.

First, 100 g of water and 26 g of isobutylene-maleic anhydride copolymer (isopan-10, manufactured by Kureha Chemical Co., Ltd.)
were mixed, 10 g of sodium hydroxide was added thereto, stirred at 80°C for 6 hours, cooled to room temperature, and pectin 3.1
% aqueous solution and stirred for 20 minutes. 200g of the above isopane-pectin mixture was added to a 20% sulfuric acid solution.
Adjust H to 4.0 and add 0.2g of Quadrol (BAS
(manufactured by Company F) was added, and this was mixed with a homomixer at 300 rpm.
Component 2 shown in Tables 1 and 2 above while stirring at m.
0g dissolved in 30g of chloroform.
Add the mixture for 15 seconds and continue to emulsify for 10 minutes.

Further, the emulsion is transferred to a 500 mA beaker, and the mixture is continuously stirred using a stirring blade for 1 to 2 hours to distill off the solvent.

Next, 8.3 g of urea solution (50% by weight), 0.4 g of resorcinol dissolved in 5 g of water, and 10.7 g of formalin (
37%) and 0.6 g of ammonium sulfate dissolved in 1011 water are added at 2 minute intervals.

After raising the temperature to 60°C and continuing stirring for 3 hours, lower the temperature and adjust the pH to 12.0 with 20% caustic soda solution.The capsule liquid was filtered, washed twice with 10100O water, and dried. A microcapsule-shaped image forming element is obtained.

The particle size of the image forming element obtained was 7 to 15 μm, with an average particle size of 10 μm. The photopolymerization initiator in the image forming element shown in Table 1 absorbs light in the band of graph A in the light absorption characteristics shown in FIG. The photopolymerization initiator in the image-forming element shown in Table 2 absorbs light in the band shown in graph B in FIG. 2 to start a reaction, and the color becomes blue during image formation.

Table 1 Table 2 The image forming element formed as described above was bonded to a support made of PET with a binder to form a transfer recording medium as shown in FIG. To explain this process in more detail, first, the polyester adhesive Polyester-LP-011 (solid content 50%) manufactured by Nippon Gosei Kagaku Kogyo Co., Ltd.
Adhesive ib made by dissolving 3 cc of toluene in cc
was applied onto a support la made of a polyethylene terephthalate film with a thickness of 6 um. Then dry the solvent,
When it was removed and the thickness was measured, it was approximately ILLm. Since the adhesive 1b has a glass transition point of 14° C., minute tack remains even at room temperature, so the image forming element formed as described above can be easily attached to the support 1a. Next, on the film provided with the layer of adhesive 1b, a microcapsule-shaped image forming element having a core material of the composition shown in Tables 1 and 2 obtained as described above was applied at a ratio of 1:1. They were mixed in the following proportions and sprinkled on to adhere. Thereafter, when the excess image forming element was brushed off, the image forming element was arranged on the adhesive layer in approximately one layer and at a ratio of 90%.

Thereafter, a pressure of about 1 kg/cm2 and thermal energy of about 110"c is applied to the transfer recording medium 1 to firmly fix the image forming element on the support la, thereby forming a transfer recording layer. A transfer recording medium 1 was constructed.

The transfer recording medium obtained in this way is wound and a fourth
It was assembled into the device shown in the figure.

In FIG. 4, reference numeral 1 denotes a transfer recording medium, which is wound into a roll and is removably incorporated into the main body of the apparatus as a supply roll 2. In FIG. That is, this supply roll 2 is removably loaded onto a rotatable shaft 2a provided in the main body of the apparatus. The transfer recording medium 1 is fed out in the direction of the arrow a, and is sequentially wound around the take-up roll 6.

The transfer recording medium 1 fed out from the supply roll 2 first reaches the recording section 3 . The recording section 3 is composed of heating means and light irradiation means.

The heating means is composed of a line-type heating element row 3b that generates heat according to an image signal is arranged on the surface of a thermal head 3a, and the support side of the transfer recording medium l is heated to the heating element row 3b by pack tension during conveyance. They are configured to be pressed together with a predetermined pressure. Note that the image signal may be sent to a facsimile, an image scanner,
Alternatively, it is emitted from a control unit (not shown) such as an electronic whiteboard.

In this example, the thermal head is 8 dots/mm,
An A4 size paper was used.

On the other hand, light irradiation means is provided on the transfer recording layer side facing the thermal head 3a. Here, as light irradiation means, fluorescent lamps 3c and 3d were incorporated in the arrangement shown in FIG. The fluorescent lamp 3c is a 20W fluorescent lamp FL10 made by Toshiba, which has the spectral characteristics shown in graph A in Figure 5.
A70E39 was used, and as the fluorescent lamp 3d, a 20W Kento line fluorescent lamp FL20SE manufactured by Toshiba Corporation and having the spectral characteristics shown in graph B in FIG. 5 was used.

Next, the transfer section 4 will be explained. The transfer unit 4 is disposed downstream of the recording unit 3 in the conveyance direction of the transfer recording medium 1,
As shown in FIG. 3, a transfer roller 4a is driven and rotated in the direction of the arrow, and a pressure roller 4b is pressed against the transfer roller 4a.
It is composed of. The transfer roller 4a is composed of an aluminum roller whose surface is coated with silicone rubber, and whose surface is kept heated by a built-in heater 4C. In this example, the surface temperature was controlled to be approximately 120°C. Also, pressure roller 4
b consists of an aluminum roller, and is configured to generate a pressing force of 25 Jf/cu+' in the direction of the transfer roller 4a by means of a spring (not shown). Further, the nip between the transfer roller 4a and the pressure roller 4b was approximately 1.8 mm.

Furthermore, recording paper 8 as a recording medium loaded in the cassette 7
are fed to the transfer unit 4 by the feeding roller 9 and register rollers Oa and 10b in synchronization so as to overlap with the area on the transfer recording medium 1 where the recorded image is formed.

In the recording section 3 of the apparatus configured as described above, light and heat energy was first applied to the retransferred recording medium I sequentially fed out from the supply roll 2 at the timing shown in FIG.

The power applied to the heating element of the thermal head is 0.5 W/d.
It was set as ot. Upon the start of recording, the fluorescent lamp 3C was turned on and the thermal head 3a was energized according to the recording information. This recording start position is a position where the leading edges of the recording sheets 8 are overlapped in the transfer section 4. Now, the fluorescent lamp 3C is 50 m5e.
C was turned on, and at the same time electricity was applied for 40 m5ec. Subsequently, 10 m5 ec after the end of the energization, that is, after the lighting of the fluorescent lamp 3C ended, the fluorescent lamp 3d was turned on for 50 m5 ec, and at the same time, energization was carried out for 40 m5 ec according to the recorded information. After repeating the above operation 14 times, the lighting time of fluorescent lamps 3c and 3d will be 40 m5ec each, and the energization time will be 30 m5ec.
It was set as m5ec. That is, the fluorescent lamp 3C was turned on for 40 m5ec, and at the same time it was energized for 30m5ec, and 20m5ec after the end of the energization, that is, 10m5ecL after the end of the lighting of the fluorescent lamp 3C, the fluorescent lamp 3d was turned on and energized. The above operation was repeated up to 15 lines before the end of recording. Then, on the 14th line before the end of recording, the fluorescent lamps 3c and 3d are turned on for 5QmSec in the same way as at the beginning of recording.
Electricity was applied for 40 m5ec. The recording end position is the position where the rear ends of the recording sheets 8 are overlapped in the transfer section 4.

After forming an image with the above operation, the transfer recording medium l on which the transferred image was formed was sequentially conveyed to the transfer unit 4 together with the recording paper 8, and the image was transferred. When the image was transferred to the recording paper 8, there was a clear image on the recording paper 8 with no background fog. In this example, the length for increasing the amount of light and heat energy applied at the recording start and end portions was set to 14 lines, but the length is not limited to this. The nip width and pressure of the transfer section may be determined as appropriate. All the heat generating elements may be energized regardless of the recorded information only in one section. Furthermore, in the case of starting recording using light and thermal energy for the 14 lines of 1 m1, line 1 may be the largest, and the line may be made smaller in order.

Further, as the heating means, in addition to the method using the recording head 3a described above, a method of selectively heating using a YAG laser and a polygon mirror, etc. may be used.

In the above-mentioned embodiment, light energy and thermal energy were applied to the transfer recording layer 1b at the same time. However, even if the optical energy and thermal energy are applied separately, the result is that both energies are applied separately. Any configuration that is given is acceptable.

[Effects of the Invention] As described above, the present invention sequentially forms an image on a transfer recording medium and transfers this image to a recording medium, so it is possible to form an image even on a recording medium with a relatively low surface smoothness. Recording can be performed well. Furthermore, when the present invention is applied to multicolor recording, it is possible to obtain a multicolor image without making any complicated movements on the recording medium.
Since the amount of energy applied is large, there is no risk of background fog due to increased pressure when the recording paper enters the transfer section and when the recording paper is ejected from the transfer section.
Images with high contrast can be obtained. Furthermore, compared to the case where energy is applied throughout the entire time at the start and end of recording, the amount of energy applied at the normal printing section can be reduced, so power consumption can be reduced.

[Brief explanation of the drawing]

FIG. 1 is a diagram schematically showing the pressure applied to the recording medium;
Figure 2 shows the light absorption characteristics of the photoinitiator; Figure 3 is a schematic sectional view of the transfer recording medium used in the examples; Figure 4 is a sectional view of the apparatus used in the examples; Figure 5. is a spectral characteristic diagram of a fluorescent lamp,
FIG. 6 is a timing chart for applying light and thermal energy. 1: Transfer recording medium 2: Supply roll 3: Recording section 4: Transfer section 6: Take-up roll 7: Cassette 8: Recording paper 9: Feeding roller 10: Register roller

Claims (1)

[Claims] A transfer recording medium having a transfer recording layer whose transfer characteristics change when thermal energy and light energy are applied is conveyed, and at least one of the light and heat energy is applied to the transfer recording medium to record information. A transfer image forming step of forming a transferred image by applying light and heat energy while applying energy in a corresponding manner, and transferring the transferred image onto the recording medium by superimposing the transfer recording medium and the recording medium. An image forming method including a transfer step, wherein the amount of light and thermal energy applied is set at the start of recording, that is, near the leading edge of the recording medium, at the end of recording, that is, near the trailing edge of the recording medium, and at other parts. An image forming method characterized by different features.