FR2660331A1 - IMAGE RECEIVING SHEET FOR THERMAL IMAGE TRANSFER RECORDING SYSTEM. - Google Patents

Abstract

Image receiving sheet for use in a thermal image transfer recording system, which has an absorption coefficient (Ka) for extra pure liquid paraffin, measured by the Bristow method under a pressure of 0.1 MPa , from 0.05 to 0.75.

Description

i The present invention relates to a film The image receiver

  usable in a thermal image transfer recording system, and in particular an image receiving sheet capable of receiving images from a thermal image transfer recording medium which can be

  used repeatedly for thermal printing.

  Recording devices, such as printers

  and facsimile apparatus, which use the registration process

  nowadays widely by thermal transfer of images This is due to the fact that recording devices of this type are relatively small in size, of little manufacture

expensive and simple to maintain.

  In a conventional thermal image transfer recording medium usable with a thermal image transfer recording apparatus, a single layer of ink is

  simply formed on a support When such a recording support

  very used for printing images, parts of the

  ink layer which are heated by a thermal head are totally

  transferred to an image receiving sheet during

  the first printing operation As a result, the recording medium

  can only be used once, but never

  repeated For this reason, standard recording media

  sics are not economically advantageous.

  In order to overcome this drawback of the state of the art, the following methods have been proposed:

  (1) a layer of microporous ink is formed on a support

  port, so that the hot-melt ink that permeates the ink layer can gradually exude, as described in Japanese patent applications made available to the public Nos. 54-68253 and 55105579; (2) a porous film is placed on an ink layer formed on a support, so that the quantity of ink which exudes from the ink layer can be controlled as described in the Japanese patent application made available from the public n 58-212993; and (3) there is an adhesive layer between an ink layer and a support, so that the ink of the ink layer can gradually separate from the support as a thin layer of ink When images are printed, in the way

  described in Japanese patent applications made available to

  tion of the public n 60-127191 and 60-127192.

  However, when printing images on a

  image receiving sheet using recording media

  By thermal transfer of the images mentioned above, the density of the images obtained decreases or is modified during the

  repeated printing operations.

  Many proposals have also been made for

  outweigh the above disadvantage of image receiving sheets usable in transfer recording systems

thermal images.

  For example, Japanese patent applications made available to the public No. 57-182487, 61-217289, 61-248791,

  61-266296, 61-284486, 62-162590, 62-202788, 62-160287, 62-257888,

  62-278082, 63-19289, 63-69685, 63-178082 and 01-188392 describe image-receiving sheets which include a support and a coating layer and which have a large capacity

oil absorption.

  However, even when using the receiving sheets

  The above mentioned images, which have a high oil absorption capacity, for the thermal transfer recording of images, high resolution images cannot be obtained and a large image cannot be maintained. image density

  during repeated printing operations.

  According to the Japanese patent application made available

  from the public N O 02-9688 it is possible to obtain satisfied images

  when using an image receiving sheet with

  as a surface roughness index (Vr) of 5 ml or more according to The Bristow method (J TAP Pl Testing Method for Paper and Pulp o

  n 51-87) However, when using the recording medium -

  By thermal transfer of images repeatedly to print images on an image receiving sheet of this type, it is not possible to obtain images for a long time.

  high resolution and high density.

  Thus, the object of the present invention is to provide a

  image receiving sheet usable in a recording system

  by thermal image transfer, which is capable of receiving high resolution and high density images from a thermal image transfer recording medium which can

  be used repeatedly for thermal printing.

  This object is achieved according to the invention thanks to a

  image receiving sheet usable in a recording system

  by thermal image transfer which has an absorption coefficient (Ka), measured by the Bristow method (J TAP Pl n O 51-87) compared to Liquid paraffin (extra pure quality),

  from 0.05 to 0.75 under a pressure of 0.1 M Pa.

  The present inventor has found that a sheet having a particular range of absorption capacity for an extra pure liquid paraffin which, in the molten state, has physical properties similar to those of an ink used in a recording medium. by thermal image transfer, is useful as an image receiving sheet for thermal image transfer recording system The present invention is based on

this finding.

  The absorption coefficient (Ka) for liquid paraffin (extra pure quality) of the image-receiving sheet according to the present invention, measured by the Bristow method under

  a pressure of 0.1 M Pa, is between 0.05 and 0.75, preferably

between 0.10 and 0.50.

  When the absorption coefficient (Ka) for the paraf-

  fine liquid (extra pure quality) of the image receiving sheet is less than 0.05 under a pressure of 0.1 M Pa, the ability of the image receiving sheet to receive ink becomes poor As a result , the amount of ink that the image receiving sheet is capable of receiving during the first printing operation

  is not sufficient for obtaining high density images.

  On the other hand, when the absorption coefficient (Ka)

  for liquid paraffin (extra pure quality) of the receiving sheet

  The image size is greater than 0.75, since the sheet receives

  of images absorbs an excessive amount of ink contained in the recording medium by thermal transfer of images during the first printing operation, it is not possible

  to obtain high density images during the second operation

printing.

  In addition, it is preferable that the surface smoothness according to Bekk of the image-receiving sheet according to the present invention is between 200 and 2000 s. The Bekk smoothness, expressed in seconds, is measured by applying with a force of 98 N or 49 N one

  sheet of paper to be tested on an over-polished glass plate

  side of 10 cm 2 and by measuring the time in seconds necessary to suck 1 cm 3 of air between the glass plate and the sheet of paper by applying a vacuum of 0.5 x 105 Pa through an opening of the plate When the surface roughness of the image receiving sheet according to the present invention is located between the above values, one obtains on the image receiving sheet images

  high resolution and high density.

  The absorption coefficient (Ka) of the image-receiving sheet can be adjusted by changing the amount of coating liquid used to form a coating layer on the

  image receiving sheet and modifying the phy-

  of this coating liquid.

  Other features of the present invention appear

  will read on reading the following description of reaction modes Li-

  sation given by way of example and which are not intended for

limit the scope of the invention.

Example 1

  The following components were dispersed to prepare a coating liquid for the coating layer of a sheet.

image receiver.

  Parts by weight Calcined clay 100 Styrene-butadiene copolymer 20 Sodium polyacrylate 20 Using a fi L bar to obtain a dry layer of predetermined thickness, the above coating liquid was applied to a sheet of paper

  high quality at a rate of 30 g / m 2 to form a coating layer

  Then we calendered the coating layer to obtain a

  image receiving sheet according to the present invention.

  The absorption coefficient (Ka) for liquid paraffin (extra pure quality) under a pressure of 0.1 M Pa, of the image-receiving sheet prepared above was equal to 0.51 and

  its surface smoothness according to Bekk was 165 s.

Example 2

  The following components were dispersed to obtain a coating liquid to form the coating layer

an image receiving sheet.

  Parts by weight Silica 100 Water-soluble polyester resin 40 10% aqueous casein solution 100 Calcium sterate 2 Water 63 By means of a wire rod, the coating liquid prepared above was applied to a sheet of high

  quality at a rate of 10 g / m 2 to obtain a coating layer.

  Then, this coating layer was subjected to calendering to

  obtain an image-receiving sheet according to the present invention

  tion. The absorption coefficient (Ka) for paraffin

  liquid (extra pure quality) from the pre-image receiving sheet

  trimmed above was 0.15 under a pressure of 0.1 M Pa, and its

  Bekk's surface smoothness was 530 s.

Example 3

  We prepared a paper made by hand using the

  following constituents: Parts by weight ** LBKP (with 350 m CSF * 80 LBKP (with 350 ml CSF) 80 NBKP (with 350 ml CSF) 20 Calcium carbonate 3 Water 7 Cationic starch 0.02 (*) CSF = standard Canadian dripping index (the dripping of a paste is measured by submitting 1000 ml of a suspension

  aqueous refined dough containing 3 g of dry dough to a filter

  tion on a filter cartridge to measure the amount of water

  from the dispersion This amount of water gives indications

  the properties of the refined dough).

  (**) leafy kraft pulp (Leaf tree breached kraft pulp embroidery) (***) coniferous kraft pulp (needle-leaf tree breached kraft pulp) The paper obtained above was immersed in a mixture of a solution aqueous at 5% of a polyvinyl alcohol of the trade "PVA 217" (registered trademark), manufactured by the company Kuraray Co, Ltd, and of a waterproofing agent of the trade "Polyfix" (registered trademark), manufactured by the company Showa Highpo Lymer Co, Ltd, at a temperature of 70 C for 5 min Then, we compressed this

  handmade paper using a press and dried at 60 C.

  There was thus obtained an image receiving sheet according to the present invention. The absorption coefficient (Ka) for paraffin

  liquid (extra pure quality) from the pre-image receiving sheet

  trimmed above was equal to 0.26 under a pressure of 0.1 M Pa and

  its surface smoothness according to Bekk was equal to 360 s.

  Comparative Example 1 A sheet of commercial paper "TRW-1" (registered trademark) manufactured by the company Jujo Paper Mfg Co, Ltd. was prepared in the form of a comparative image receiving sheet. OS The absorption coefficient (Ka) for paraffin

  liquid (extra pure quality) from the image receiving sheet

  parative above was equal to 1.01 under a pressure of 0.1 M Pa

  and its surface smoothness according to Bekk was 205 s.

  Comparative Example 2 We prepared in the form of an image-receiving sheet

  comparison a sheet of coated commercial paper.

  The absorption coefficient (Ka) for paraffin

  liquid (extra pure quality) from the image receiving sheet

  parative above was equal to 0.03 under a pressure of 0.1 M Pa

  and its surface smoothness according to Bekk was equal to 2050 s.

  The image receiving sheets prepared above according to the present were subjected to a thermal printing test.

  invention as well as the receiving sheets of comparative images.

  In this thermal printing test, a recording medium by thermal transfer of images prepared by the manufacturer was used.

following process.

  Preparation of a hot-melt ink A mixture of the following constituents was placed in a

  sand mill and dispersed it at 110 ° C to obtain a dispersion

uniform ink supply.

  Parts by weight Carbon black 15 Candelilla wax 60 Polyethylene oxide wax 23 Terpene resin (dispersant) 2 The ink dispersion obtained was cooled to 65 C

  this ink dispersion was added 10 parts by weight of a colo-

  rant with a low oil-soluble melting point, Benzol black (registered trademark), and 675 parts by weight of a solvent consisting of a 2: 1 mixture of methyl ethyl ketone and toluene, then the mixture was again dispersed obtained at 32 C We then cooled

  this mixture at room temperature to obtain a thermo ink

gelled fuse.

  Formation of a first ink layer A mixture intended to form a first ink layer was prepared by dispersing the following constituents: Parts by weight Gelled hot-melt ink (prepared as above) 10 20% solution of a vinyl chloride-vinyl acetate copolymer in a mixed solvent 3 (2: 1) of methyl ethyl ketone and toluene Azobisisobutyronitrile 0.1

  A surface was treated with a film of poly (ethylene-

  terephthalate) (PET) with a thickness of 4.5 µm to make it resistant

aunt in the heat.

  On the opposite surface of the PET film the above prepared mixture was applied to a thickness of 8 µm, then dried at 75 ° C to form a first layer of ink on the PET film. Formation of a second layer of ink A mixture was prepared intended to form a second

  ink layer by dispersing the following constituents.

  Parts by weight Gelled hot melt ink (prepared as above) 10 20% solution of a vinyl chloride-vinyl acetate copolymer in a mixed solvent 3 of methyl ethyl ketone and toluene (2: 1) On the first layer of ink prepared above, the mixture prepared above was applied to a thickness of 2 μm, then dried at 110 ° C. to form a second layer of ink

  porous on the first layer of ink We thus obtained a sup-

  recording port by thermal image transfer.

  The thermal image transfer recording medium prepared above was placed in a line thermal printer and images were transferred four times to each of the image receiving sheets of the present invention and the image receiving sheets. comparative images from the same part of the recording medium, under the following conditions: Thermal head: Plate pressure: Peel angle relative to the image receiving sheet: Energy applied by the thermal head Printing speed: head thin film type 22 x 103 Pa (230 gf / cm) 23 m J / mm 2, 1 cm / s (2 inch / s) The density of the McBeth RD-914 reflection densitometer was measured images obtained at the time of the first, second, third and fourth

  The results are presented in Table 1.

TABLE 1

  Example n Image density 1 st 2 nd 3 rd 4 th example 1 1.48 1.36 1.27 0.93 example 2 1.32 1.13 1.12 1.04 example 3 1.42 1.39 1 , 31 1.11

example compa-

rat 1 1.44 1.36 0.95 0.51

example compa-

  rat 2 1.04 0.81 0.80 0.76 type each

print-

  As shown in the table above, we can get

  repeated high density images on the receiving sheets

  images according to the present invention including the absorption coefficient (Ka) for liquid paraffin (extra pure quality)

is between 0.05 and 0.75.

  In addition, when using image-receiving sheets for thermal printing having an absorption coefficient (Ka) for liquid paraffin (extra pure quality) of between 0.05 and 0.75 and a smoothness of surface according to Bekk between 200 and 2000 s, we obtain images with excellent resolution.

Claims (2)

  1 Image-receiving sheet usable in a thermal image transfer recording system, characterized in that it has an absorption coefficient (Ka) for paraffin   extra pure liquid, measured by the Bristow method under a pressure 0.1 M Pa, 0.05 to 0.75.   2 image-receiving sheet according to claim 1, characterized in that it has a surface smoothness according to Bekk of 200 at 2000 s. 1