JPH10119333A - Method and device for recording - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve a transferring property and to enhance reliability in high speed recording and color recording by a method wherein a latent image is formed on a special recording medium and is developed, then the recording medium is supported by an elastic body at a portion where a coloring material forming an image is transferred to a recording paper and a transferring pressure having a specific value is applied thereto at the transferring portion. SOLUTION: A recording body 1, which is formed such that a recording layer having a characteristic that a retraction contact angle against a liquid is lowered when it is heated and cooled by being in contact with the liquid, is provided to a base body. Printing is performed by surely holding the recording body 1 on an elastic holding member 6. In the case where the recording body is detachably attached to the elastic holding member 6, it is possible to exchange the recording body when it is deteriorated so that the reliability is enhanced. When the recording body 1 is deformed along the irregularities of a paper 20 at a transferring section, it is good to raise a transferring pressure, but when it is too high the rubbing resistance of the recording body is possibly deteriorated. The transferring pressure is preferably set to one MPa or more when considering that at least 1.0 is required for an image density.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a recording method and apparatus, and more particularly, to a recording method in which an image is formed on a surface of a recording medium having a specific property and the image is transferred to a recording medium (recording paper). The present invention relates to a method and an apparatus useful for performing the method.

[0002]

2. Description of the Related Art Many recording methods, such as magnetic, optical, and chemical, have been proposed and put to practical use. Among them, the printing method and the electrophotographic method are widely used because they can be easily and easily obtained from a small number to a large number.

[0003] Among the printing methods, the lithographic printing method is more optimal than the other printing methods when performing plate making printing and considering the above-mentioned number of copies. However, the lithographic printing method is generally an offset printing method, in which only the ink on the plate is transferred to a blanket and then printed on paper. However, some lithographic printing methods do not use dampening water, so-called waterless lithographic printing plates, and have the advantage that direct printing can be performed.

However, in the offset printing method, a new printing plate material can be used a plurality of times. However, for this purpose, the complexity of having to perform a new graining operation on the printing plate after one printing is completed. is there. The present inventors have eliminated such complications and very easily obtained copies.
In addition, an image forming method and apparatus capable of easily performing repetitive plate making have been proposed in, for example, Japanese Patent Application Laid-Open No. 3-178478.

The above proposed method / apparatus uses a recording medium provided with a recording layer on a substrate, which has a property in which the receding contact angle with respect to the liquid decreases when heated or cooled in contact with the liquid. is there. FIG. 6 shows a method of forming a latent image on the recording layer 1 on the surface of the recording material by, for example, a thermal head 2 to form a visible image with ink supplied from a developing roller 3, and directly transferring this to a recording paper 20. 1 shows an outline of the apparatus. In the drawing, reference numeral 4 denotes ink (image), and reference numeral 5 denotes a pressure roller disposed at a transfer site. According to the direct printing transfer mechanism, there are advantages that the number of device parts can be reduced and the size of the device can be reduced.

[0006]

However, according to the means using the above-mentioned recording medium (a recording layer having only a recording layer formed on a substrate), a high-quality image cannot often be obtained on recording paper. Sometimes. In addition, since the paper surface is generally uneven, the recording layer coating is likely to be destroyed at the contact surface between the paper and the recording layer. For this reason, the recording layer is required to have a coating hardness at least not to be destroyed. On the other hand, when the recording layer coating is too hard, there is no problem in ink transferability with smooth paper having relatively small irregularities on the paper, but the recording layer coating is hard on paper with large irregularities such as PPC paper and type paper. Therefore, as shown in FIG. 7, there is a problem that the ink 4 does not come into contact with the concave portion 30 on the surface of the paper and transfer failure occurs. It is conceivable to increase or decrease the thickness and hardness of the substrate 1a. In this case, however, increasing the thickness of the substrate increases the cost, and decreasing the hardness of the substrate easily expands the recording medium and easily cracks the hard recording layer. Inconvenience is seen.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a recording method and apparatus which are particularly focused on holding a recording medium and have excellent transferability to plain paper (recording paper).

[0008]

According to the present invention, first, a recording layer is provided on a substrate, the recording layer having a property that the receding contact angle with respect to the liquid is reduced when the substrate is heated and cooled in contact with the liquid. After forming and developing a latent image on a recording medium using a recording medium, at least a portion where a color material constituting the image is transferred to recording paper, the recording medium is held by an elastic member. A recording method is provided.

Secondly, there is provided a recording method according to the first recording method, wherein a transfer pressure at a transfer portion is set to 1 MPa or more.

Further, according to the present invention, thirdly, a recording medium provided with a recording layer having a property of decreasing a receding contact angle with respect to a liquid when the substrate is heated or cooled while being in contact with the liquid; In a recording apparatus including at least a developing unit and a pressure transfer unit, an elastic member is provided on the back surface of the base, or an elastic holding member is provided at the pressure transfer site so as to be in close contact with the back surface of the base. A recording device is provided.

Fourthly, there is provided a recording apparatus according to the third recording apparatus, wherein cleaning means is provided at a position subsequent to the pressure transfer portion and in contact with the surface of the recording medium.

Fifthly, there is provided the recording device according to the third or fourth recording device, wherein the coating hardness of the recording layer is 1H or more in pencil hardness.

Sixth, there is provided a recording apparatus according to the third or fourth recording apparatus, wherein at least the surface of the base has high friction or adhesiveness.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in more detail. Here, the description will be made by taking transfer direct printing as an example. However, the method and apparatus of the present invention may employ a so-called offset method in which an ink image formed on a recording medium is transferred to recording paper via a blanket cylinder. That is natural.

The recording medium of the present invention is a "recording medium provided with a recording layer having a property that the receding contact angle with respect to the liquid is reduced when heated and cooled in contact with the liquid". As the material of the recording layer, a recording layer having a reduced receding contact angle when heated and brought into contact with a liquid is provided. "Liquid" here means, in addition to liquid,
The liquid may be a liquid or a liquid or a solid that generates a vapor at a temperature equal to or lower than the temperature at which the receding contact angle of the recording medium decreases. This is because the vapor condenses on the surface of the recording medium or in the vicinity thereof and turns into a liquid, and the vapor generated from the solid condenses on the surface of the recording medium or in the vicinity thereof to produce a liquid.

The description and specific examples of the substances constituting the recording layer include all of the polymer materials described in JP-A-3-178478. Preferably, it is a polymer material containing fluorine, and when it does not contain fluorine, a polymer having a long alkyl group side chain such as a lauryl methacrylate polymer or a stearyl acrylate polymer can be used. Among them, the use of a material represented by the following formula is particularly preferred.

Embedded image

In order to improve the contact with the recording paper when the recording layer is hard, the present inventors have made the recording medium thinner,
It was confirmed that it was effective to use an elastic material for the holding member of the recording medium. This seems to be based on the following reasons. FIG. 1 shows a contact portion between a recording medium and paper at a transfer site.
As shown in FIG. 1, when the thickness of the recording medium 1 is reduced, the recording medium 1 is easily deformed along the irregularities of the paper 20. However, when the recording body 1 is made thinner, the mechanical strength is reduced. Therefore, the elastic holding member 6 is provided on the back side of the recording body 1 at the transfer portion. Further, the elastic holding member 6 has moderate elasticity (rubber hardness 30 to
80) The recording medium can be efficiently deformed along the paper by applying the transfer pressure efficiently.

The present inventors measured the solid image density on the paper after transferring the ink to the paper while changing the thickness of the recording medium under a constant transfer pressure (see FIG. 2). It has been found that the image density tends to increase as the thickness decreases.
However, if the thickness of the recording medium is reduced as much as possible, the mechanical strength is inferior even if there is a holding member. Therefore, as a result of investigations by the present inventors, the recording medium has a mechanical strength that does not cause a problem in conveyance in the apparatus, and the thickness at which the transfer property is improved is 4 to
It has been found that it is desirable to be in the range of 10 μm. When the thickness of the recording medium is 10 μm or less, it is desirable that the recording medium has a two-layer structure of a substrate having a high tensile strength and a recording layer in consideration of the reliability of mechanical strength.

The recording medium only needs to be held by the elastic holding member at the transfer portion. In the case of high-speed recording of 40 sheets / min.
When the thickness is less than μm, the mechanical strength of the recording medium is insufficient. Therefore, if the recording apparatus is configured as shown in FIG. 3, the recording medium tends to be easily elongated or detached from the transport system. Therefore, in order to solve this problem, it is desirable that the entire printing area of the recording medium be held by the elastic holding member during printing.

FIG. 4 shows a specific configuration of an apparatus which is more preferable for performing the method of the present invention. The recording body 1 is securely held on the elastic holding member 6 and performs printing. Further, if the recording medium 1 is made detachable from the elastic holding member 6, it can be replaced when the recording medium is deteriorated, and the reliability is improved. Also,
In the case of a printing apparatus that requires positional accuracy, such as color printing, in which each color is superimposed, holding the entire printing area of the printed body makes it difficult for the printed body to be misaligned and increases the positional accuracy.

Although the thickness of the recording medium is desirably 4 to 10 μm or less, the recording medium 1 is composed of the substrate 1a and the recording layer 1b. It is desirable that the hardness is high. However, when the coating is hard, the recording layer loses flexibility and cracks easily occur in the recording layer due to bending of the recording medium. When the recording medium is deformed along the irregularities of the paper at the time of transferring the recording medium to 10 μm or less as in the present invention, the recording medium slightly bends. Therefore, when the recording layer is hard, cracks may occur.

To solve this problem, the present inventors have studied to make the recording layer as thin as possible. In general, even a hard plate material such as glass is hardly broken by bending by reducing the thickness. This is because the thinner the thickness, the smaller the difference between the radii of curvature on both sides of the plate material with respect to bending, and the smaller the internal stress of the plate material. As a result of the study by the present inventors, it was found that when the coating hardness is 3B or more, if the coating of the recording layer is 2 μm or less, no serious crack occurs in the recording layer due to the degree of deformation of the recording medium due to close contact with paper. . From this, the thickness of the recording layer is 0.1 to 2 μm, preferably 0.2 to 1 μm.
The thickness of the substrate is 10 μm depending on the thickness of the recording layer.
m, preferably in the range of 4 to 10 μm.

The substrate of the recording medium needs to have heat resistance because it is heated when an image is written by a thermal head, a laser beam or the like. Further, since the entire recording medium is moved in order to convey the recording medium from the image writing to the transfer site, it is necessary to select a member having excellent pulling strength. Specifically, it is desirable to use a metal film such as nickel or stainless steel, or a resin film such as polyethylene terephthalate (PET), polyimide, or polycarbonate.

As shown in FIGS. 3 and 4, at the portion where the color material constituting the image portion on the recording medium is transferred to the recording paper, as a material of the elastic holding member arranged on the back side of the recording medium, Rubber materials such as urethane rubber, natural rubber, chloroprene rubber, NBR rubber and butyl rubber are suitable. Rubber hardness is 3
0 to 80 is desirable.

Next, when the recording medium is deformed along the irregularities of the paper at the transfer portion, it is better that the transfer pressure is high. However, if the transfer pressure is too high, the printing durability of the recording medium may be deteriorated. is there. In addition, there is a possibility that the device becomes large and the weight becomes large. Then, the minimum transfer pressure which shows sufficient transferability was examined. The result is shown in FIG. Considering that an image density of at least 1.0 is required, the transfer pressure may be 1 MPa or more, and preferably 1 to 2 MPa.
MPa.

The recording apparatus of the present invention comprises a recording medium, a developing means,
A pressure transfer unit is provided, and an elastic holding member is provided on the back surface of the substrate of the recording body, or the elastic holding member is brought into close contact with the substrate surface of the recording body at the pressure transfer portion. Desirably, the former is selected.
The elastic modulus of the elastic holding member is suitably in the range of 5 × 10 ⁵ to 10 ¹¹ N / m ² . In this way, only the plate cylinder (recording member holding member) is made to be an elastic body, so that ink transfer from the plate is favorably performed. If necessary, the developing roller 3 may be an elastic body depending on the way of supplying ink.

At the transfer site, the paper and the recording medium slightly rub when the recording medium is deformed along the irregularities of the paper when it comes into close contact with the paper. Therefore, it is desirable that the recording layer coating is hard in consideration of the scratch resistance. As a result of the study by the present inventors, it was found that there was no problem if the coating hardness was H or higher in pencil hardness.

As described above, the contact with paper when printing on a recording medium (plate) is very important. Contact must be maintained against large undulations and small scratches.
Normally, in the case of a soft elastic body, for example, a soft rubber, a rough surface appears even when ground, and there is a tendency that contact corresponding to the above-mentioned flaw is difficult. Further, when the thickness of the support layer of the recording medium is reduced in consideration of cost and the like, a phenomenon occurs in which the recording medium is difficult to hold on the plate cylinder (elastic holding member).

In the apparatus of the present invention, when the elastic holding member is deformed, as described above, depending on the method of holding the recording body by the elastic holding member, the recording medium may slip due to slippage. Therefore, if the friction coefficient of the surface of the elastic holding member is increased, the recording body and the elastic holding member are in contact with each other on the deformed surface. Therefore, it is advantageous that the surface of the elastic holding member is made of a high friction material. At this time, the elastic holding member may be made of high friction rubber such as EPDM, or a high friction material may be applied and baked. Further, a material exhibiting high friction characteristics may be used or applied to an elastic body having a relatively hard surface. As the coating material, for example, a polyurethane material or the like can be considered.

In addition, if the surface of the elastic holding member is provided with an adhesive property from the beginning, the effect of preventing the recording medium from shifting can be more recognized. To make such an elastic holding member,
A material having an adhesive property may be used for the elastic holding member, and a material having an adhesive property may be applied to the surface of the elastic holding member or baked. For example, a silicone rubber or the like is listed as an elastic material showing adhesiveness, and a spray paste 55 (Sumitomo 3M) containing a synthetic rubber (such as acrylic rubber) and an organic solvent (such as isohexane) is used as a coating material showing adhesive properties. Company).

Meanwhile, on an elastic surface exhibiting high friction characteristics or a surface exhibiting adhesive characteristics, the surface characteristics often deteriorate due to paper dust or the like while the recording apparatus is used for a long time. Therefore, in order to restore the respective characteristics, it is desirable to attach a cleaning unit after the transfer portion and to attach the cleaning unit. The cleaning unit does not need to be kept in contact with the plate (recording body) at all times, but is configured to be separated from the plate cylinder when replacing the plate.
A cleaning unit that wipes with alcohol or the like as a material for restoring high friction materials and adhesive materials is preferred. In the case where a high friction material or an adhesive material is applied, the application may be performed in the apparatus.

In the recording apparatus of the present invention, a cleaning means (for example, a cleaning roller shown in FIGS. 3 and 4) is provided separately from the above-described cleaning unit to remove stains and ink residue on the surface of the recording medium. Is desirable. This cleaning means can substitute the above-mentioned cleaning unit.

[0033]

Next, the present invention will be described in detail with reference to examples.

Example 1 Recording substrate: polyethylene terephthalate (PET) film (Toray, thickness 6 μm, 9 μm, 25 μm). Recording layer: 20% by weight of perfluoroalkyl acrylate copolymer (fluorine content: 40%) and 1.4 of emulsifier
An aqueous dispersion (LS317, manufactured by Asahi Glass Co., Ltd.) containing 1% by weight was used as a recording layer raw material. This was mixed in pure water to obtain a coating solution having a solid content of 10% by weight. The coating method was such that a substrate was coated by a wire bar method, and then heated and dried at 120 ° C. for 30 minutes (thickness: 0.5 μm). Apparatus configuration: the configuration shown in FIG.
(Held by the elastic holding member at the transfer section). Ink: Commercial lithographic ink without water. Image writing means: 400 dpi thermal head. Cleaning: urethane sponge containing ink solvent. (Elastic) holding member: chloroprene rubber roller (rubber hardness 60 degrees). Recording paper: PPC paper (type 620, manufactured by Ricoh Company)
0). Solid images were printed on paper using recording media of each thickness. After printing, measure the image density on the paper using a Macbeth densitometer,
As shown in FIG. 2, the image density increased as the thickness of the recording medium decreased.

Example 2 Recording medium substrate: polyethylene terephthalate (PET) film (6 μm thick, manufactured by Toray Industries, Inc.) Recording layer: 20% by weight of perfluoroalkyl acrylate copolymer (fluorine content: 40%) and 1.4 of emulsifier
An aqueous dispersion (LS317, manufactured by Asahi Glass Co., Ltd.) containing 1% by weight was used as a recording layer raw material. This was mixed in pure water to obtain a coating solution having a solid content of 10% by weight with pure water. The coating was performed by a substrate wire bar method, followed by heating and drying at 120 ° C. for 30 minutes (thickness: 1 μm). Apparatus configuration: the configuration shown in FIG. Ink: Commercial lithographic ink without water. Image writing means: 400 dpi thermal head. Developing means: fluorine rubber roller. Recording paper: PPC paper (type 620, manufactured by Ricoh Company)
0). Elastic holding member: urethane rubber (rubber hardness 70). The printing evaluation at a printing speed of 40 sheets / min. A4, 60 sheets / min. A4, 80 sheets / min. A4, 120 sheets / min. As a result, 80 sheets /
In the case of minute / A4 and 120 sheets / minute / A4, in the configuration of FIG. 3, the recording medium detached from the transport system in repeated printing. On the other hand, in the configuration of FIG. 4, there was no problem even at 120 sheets / minute / A4.

Example 3 Recording substrate: polyethylene terephthalate (PET) film (Toray, 6 μm thick). Recording layer: Crosslinked film of perfluoroalkyl acrylate copolymer (Modiper F, manufactured by NOF Corporation). This is due to the recording layer thickness of 0.2 μm, 1 μm, 2 μm
Was formed. Apparatus configuration: the configuration shown in FIG. Ink: Commercial lithographic ink without water. Image writing means: 400 dpi thermal head. Developing means: fluorine rubber roller. Recording paper: PPC paper (type 620, manufactured by Ricoh Company)
0). Elastic holding member: urethane rubber (rubber hardness 70). In the configuration of FIG. 4, after transferring the recording medium of each recording layer thickness to paper,
When the surface of the recording layer was observed, no abnormality was found in the film of the recording layer having a thickness of 0.2 μm and 1 μm. 2 μm coating
Although slight cracks were observed, there was no problem in image quality.

Example 4 Recording medium substrate: polyethylene terephthalate (PET) film (manufactured by Toray Industries, thickness 9 μm). Recording layer: Crosslinked film of perfluoroalkyl acrylate copolymer (Modiper F, manufactured by NOF Corporation). This is because after coating the substrate by the wire bar method, 120
This was prepared by heating and drying at 30 ° C. for 30 minutes (thickness: 1 μm). Apparatus configuration: the configuration shown in FIG. Ink: Commercial lithographic ink without water. Image writing means: 400 dpi thermal head. Developing means: fluorine rubber roller. Recording paper: PPC paper (type 620, manufactured by Ricoh Company)
0). Recording member holding member: chloroprene rubber (rubber hardness 70). The image density (Macbeth densitometer) of the solid image on the paper after the transfer was measured by changing the transfer pressure. As shown in the measurement results in FIG. 5, it was found that the transfer pressure should be 1 MPa or more in order to make the image density 1.0 or more.

Example 5 Recording medium substrate: polyethylene terephthalate (PET) film (manufactured by Toray Industries, thickness 9 μm) Recording layer: cross-linked film of perfluoroalkyl acrylate copolymer (Modiper F, manufactured by NOF Corporation). This is done by coating the substrate with a wire bar method,
It was prepared by heating and drying for 0 minutes. The hardness of the film was adjusted by changing the degree of crosslinking. Ink: Commercial lithographic ink without water. Image writing means: 400 dpi thermal head. Developing means: fluorine rubber roller. Recording member holding member: chloroprene rubber (rubber hardness 60). Recording paper: PPC paper (type 620, manufactured by Ricoh Company)
0). Apparatus configuration: the configuration shown in FIG. Evaluation of the abrasion at the time of transfer using a recording medium having a recording layer of each coating hardness was carried out, and it was found that scratching due to paper occurs unless the hardness is higher than the pencil hardness H.

[0039]

According to the first aspect of the present invention, the transferability is improved and the image quality is improved as compared with the prior art. According to the invention of claim 2, the reliability in high-speed printing and color printing is improved. According to the third aspect of the present invention, cracks are less likely to occur in the coating film, so that printing durability is improved. According to the fourth aspect of the present invention, it is not necessary to set the transfer pressure unnecessarily high, so that it is possible to avoid an increase in the size of the apparatus and an increase in cost. According to the invention of claim 5, since the hardness of the coating film can be optimized, the scratch resistance is improved. According to the invention of claim 6, the recording body is firmly held by the elastic holding member at the time of printing, and high quality recording without deviation can be performed.

[Brief description of the drawings]

FIG. 1 is a view for explaining how a transfer image is formed on a paper surface using a recording medium of the present invention.

FIG. 2 is a diagram illustrating the relationship between the thickness of a recording medium and the density of a transfer image obtained.

FIG. 3 is a diagram schematically showing an apparatus of the present invention.

FIG. 4 is a diagram schematically showing another apparatus of the present invention.

FIG. 5 is a diagram showing how recording is performed by a conventional method.

FIG. 6 is a diagram illustrating a state in which a transfer image is formed on a sheet of paper by a conventional method.

FIG. 7 is a diagram showing a state in which transfer failure occurs without ink contacting a concave portion on the paper surface.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Recording body (1a base, 1b recording layer) 2 Thermal head 3 Developing roller 4 Ink 5 Pressure roller 6 Elastic holding member 7 Cleaning roller 20 Recording paper 30 Depression

Claims (6)

[Claims] 1. A recording medium provided with a recording layer having a property that a receding contact angle with respect to a liquid is reduced when heated or cooled in a state of being in contact with a liquid on a substrate, and a latent image is formed on the recording medium. A recording method comprising: after developing, at least at a portion where a color material constituting the image is transferred to recording paper, the recording medium is held by an elastic member. 2. The recording method according to claim 1, wherein the transfer pressure at the transfer portion is 1 MPa or more. 3. A recording medium provided with a recording layer having a property in which a receding contact angle with respect to a liquid is reduced when heated or cooled in a state in which the liquid is in contact with the liquid, a developing means, and a pressure transfer means. A recording apparatus provided with at least an elastic member provided on the back surface of the base or an elastic holding member closely contacting the back surface of the base at a pressure transfer portion. 4. The recording apparatus according to claim 3, wherein a cleaning unit is provided at a position subsequent to the pressure transfer portion and in contact with the surface of the recording medium. 5. The recording apparatus according to claim 3, wherein the coating hardness of the recording layer is 1H or more in pencil hardness. 6. The recording apparatus according to claim 3, wherein at least the surface of the substrate has high friction or adhesiveness.