Classifications

• • D—TEXTILES; PAPER
  • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
  • D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
  • D21H19/00—Coated paper; Coating material
  • D21H19/36—Coatings with pigments
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
  • B41M—PRINTING, DUPLICATING, MARKING, OR COPYING PROCESSES; COLOUR PRINTING
  • B41M5/00—Duplicating or marking methods; Sheet materials for use therein
  • B41M5/50—Recording sheets characterised by the coating used to improve ink, dye or pigment receptivity, e.g. for ink-jet or thermal dye transfer recording
  • B41M5/502—Recording sheets characterised by the coating used to improve ink, dye or pigment receptivity, e.g. for ink-jet or thermal dye transfer recording characterised by structural details, e.g. multilayer materials
  • B41M5/508—Supports
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
  • B41M—PRINTING, DUPLICATING, MARKING, OR COPYING PROCESSES; COLOUR PRINTING
  • B41M5/00—Duplicating or marking methods; Sheet materials for use therein
  • B41M5/50—Recording sheets characterised by the coating used to improve ink, dye or pigment receptivity, e.g. for ink-jet or thermal dye transfer recording
  • B41M5/52—Macromolecular coatings
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
  • B41M—PRINTING, DUPLICATING, MARKING, OR COPYING PROCESSES; COLOUR PRINTING
  • B41M5/00—Duplicating or marking methods; Sheet materials for use therein
  • B41M5/50—Recording sheets characterised by the coating used to improve ink, dye or pigment receptivity, e.g. for ink-jet or thermal dye transfer recording
  • B41M5/52—Macromolecular coatings
  • B41M5/5218—Macromolecular coatings characterised by inorganic additives, e.g. pigments, clays
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
  • B41M—PRINTING, DUPLICATING, MARKING, OR COPYING PROCESSES; COLOUR PRINTING
  • B41M5/00—Duplicating or marking methods; Sheet materials for use therein
  • B41M5/50—Recording sheets characterised by the coating used to improve ink, dye or pigment receptivity, e.g. for ink-jet or thermal dye transfer recording
  • B41M5/52—Macromolecular coatings
  • B41M5/5254—Macromolecular coatings characterised by the use of polymers obtained by reactions only involving carbon-to-carbon unsaturated bonds, e.g. vinyl polymers

Definitions

• This invention relates to a recording paper and an ink jet recording method which comprises impinging aqueous ink droplets onto the recording paper.
• the paper exhibits good absorptivity for aqueous ink, permits good image resolution and colour forming characteristics by the colourant in the ink.
• the recording paper (1) exhibits good ink absorptivity, ink penetrates deep into the fibrous layer of the paper and therefore the colour forming characteristics of the colourant in the ink is poor. Since the ink is also absorbed along the fibres at the surface of the paper, a phenomenon called feathering occurs in which the dots formed are not circular but irregular in shape which reduces the resolution available and the quality of the resulting image.
• the ink absorbing layer is porous and uniform.
• a relatively thick ink absorption layer is required to give sufficient ink absorptivity and the problem therefore arises that a single coating is insufficient, and a plurality of coatings have to be applied.
• the ratio of the pigment to the binder (P/B) in the ink absorbing layer is increased in order to increase the ink absorptivity, there is a risk of the pigment dropping off the paper (powder drop-off) and this can cause slippage of delivery rollers for the paper or clogging of the nozzles of the ink jet printer.
• the recording paper (3) has the advantage of providing a recording medium having good ink absorptivity and good colour forming characteristics as compared with the recording paper (2) even where the coating layer provided is relatively thin.
• the present invention provides a recording paper comprising a fibrous substrate coated with 2-10gm2 dry weight of a coating containing a silicon-containing pigment which has an oil absorption according to JIS K 5101 in the range 80-300ml/100g, the paper having:
• the above recording paper exhibits little powder drop off, is inexpensive to produce and exhibits good ink absorptivity and good colour forming properties. It can produce images at high resolution and does not give rise to significant "cockling” or "backthrough” problems at regions where printed images appear.
• the invention further provides a method for making a recording paper as aforesaid, which comprises coating the fibrous paper substrate at a speed of 60 to 200 m/min with an aqueous coating liquid comprising the silicon-containing pigment and a binder, the liquid having a viscosity at 30° C measured at 60 rpm by a B-type viscometer of 60-200 cps, and subsequently drying the coated paper.
• the invention further provides an ink jet recording method which comprises impinging aqueous ink droplets onto the aforesaid recording paper.
• the substrate paper to be used in the present invention is a sheet containing fibrous material and, if necessary, a pigment, having a Stöckigt sizing degree according to JIS P8122 in the range of 0 to 15 sec. (based on the basis weight of 65 g/m2), and any paper made to a sizing degree of 0 to 15 sec. by a suitable sizing agent according to the acidic sheet making method or the neutral sheet making method known in the art can be used.
• the sizing degree of the substrate paper should be preferably in the range of 0 to 10 sec., more preferably in the range of 0 to 5 sec. Also, in aspect of coating stability of the coating liquid, it is preferably one sec. or more.
• the basis weight of the above paper is also an important factor. More specifically, the basis weight of the substrate paper to be used in the present invention is required to be within the range of 80 to 200 g/m2. If the basis weight is less than the above range, the so called stiffness of the recording paper is weak to pose a problem in carriage characteristic within the printer during printing, and also to lack ink absorption capacity as the recording paper, and therefore the printing portion causes cockling to pose a problem that sharpness of the image is lowered. Also, when recording is performed by use of a printer having a plural number of recording heads, the convex portion formed by cockling will become in contact with the head during recording, whereby clogging of the head, etc. may be caused to involve the problem that irregularity may be formed in the image obtained.
• the ink not received will be subject to back-through, whereby there may be caused the problem that the ink image of the upper recording paper may be back transferred to the image of the lower recording paper when printed matters are placed as superposed on one another, or there may occur the problem that no recording can be performed on the back surface, etc.
• the thickness of the substrate paper to be used in the present invention may be preferably in the range of 50 to 250 ⁇ m. If the thickness is less than the above range, the so called stiffness of the recording paper obtained is weak, posing a problem in conveying characteristic within the printer during printing and also lacking ink absorption capacity, whereby the printing portion causes cockling to ensue the problem that sharpness of the image is lowered.
• the fibrous material constituting the above substrate paper to be used in the present invention is composed mainly of wood pulp, typically LBKP and NBKP, but various synthetic fibers or glass fibers may be mixed, if necessary.
• the aqueous coating liquid to be used in the present invention comprises primarily a silicon containing type pigment and an aqueous binder.
• the silicon containing pigment may be preferably one which is hydrophilic and contains relatively large amount of oil absorption according to JIS K 5101 in aspect of ink absorptivity and color forming property of the colorant, including for example silica, calcium silicate, aluminum silicate, magnesium silicate and the like. Among them, those with oil absorption of 80 to 300 ml/100 g, more preferably 150 to 250 ml/100 g, are preferred.
• the above silicon containing type pigment should be preferably one in which all the particles have the above oil absorption, but the pigment is not necessarily constituted of all the particles having uniform oil absorption, and it may also be a mixture of pigment with different oil absorptions. In the case of such a mixture of pigments with different oil absorptions, 60% by weight or more of the whole pigment may have the oil absorption within the above range.
• aqueous binder there may be used, for example, one or a mixture of two or more kinds selected from water-soluble polymers such as polyvinyl alcohol, starch, oxidized starch, cationized starch, casein, carboxymethyl cellulose, gelatin, hydroxyethyl cellulose, etc. and water-dispersed polymers such as SBR latex, MBR latex, vinyl acetate emulsion, etc.
• water-soluble polymers such as polyvinyl alcohol, starch, oxidized starch, cationized starch, casein, carboxymethyl cellulose, gelatin, hydroxyethyl cellulose, etc.
• water-dispersed polymers such as SBR latex, MBR latex, vinyl acetate emulsion, etc.
• the present inventors have studied variously about the characteristics of the aqueous coating liquid during coating, and consequently found that a recording paper having good ink jet recording characteristics can always be obtained stably when the liquid viscosity of the aqueous coating liquid at 30°C is in the range of 60 to 200 cps.
• the viscosity in the present invention is measured under the condition of 60 r.p.m. by B-type viscometer, and thixotropic characteristic, dilatant characteristic, etc. can be also evaluated by changing the rotational number.
• the viscosity of the aqueous coating liquid is less than 60 cps. the aqueous coating liquid will be penetrated deep into the substrate paper to fill the voids possessed by the substrate paper for absorption of ink, with the result that lowering in ink absorptivity may be brought about.
• coating irregularity may be undesirably caused due to too high a viscosity. Also, only water in the aqueous coating liquid is absorbed by the substrate paper to lower the strength of the surface layer, whereby powder drop-off, etc. may be caused.
• the viscosity of the aqueous coating liquid as described above can be controlled easily by the kinds of the above pigment and binder, combination thereof, their proportions used, the respective concentrations and the total concentration of the both, etc.
• the ratio of the silicon containing pigment to the binder used may be generally in the range of 3/1 to 1/1 (weight ratio), and an aqueous coating liquid with the total solid content ranging from about 3 to 70% by weight is preferred.
• the binder amount is more than the above range, ink absorptivity, particularly initial absorption speed of ink will be lowered. This problem is pronounced as the sizing degree of the substrtate paper is higher even within the sizing degree of 0 to 15 sec. and the basis weight is lower.
• the content of the pigment is larger than the above range, there ensues the problem of powder drop-off due to shortage in adhesive force even when a thin coating layer may be provided.
• the binder in the coating liquid will be readily absorbed by the substrate paper, it is essentially required that the proportion of the pigment should not exceed the above range.
• the problem of powder drop-off is more pronounced, particularly as the sizing degree of the substrate paper is lower.
• the viscosity of the above aqueous coating liquid is also intimately correlated with the coating speed. More specifically, the above aqueous coating liquid comprising a filler which is hydrophilic and has an oil absorption of 80 to 300 ml/100 g according to JIS K5101 and an aqueous binder frequently exhibits thixotropic viscosity like coating liquids in general.
• the coating speed may be preferably 60 to 200 m/min. when the viscosity is 60 to 200 cps. A coating speed quicker or slower than this range is not desirable, because various problems as described above will occur.
• the coating machine to be used in the present invention all known in the art may be used, but the coater suitably used in the present invention may include an air knife coater and a bar coater, etc.
• the amount of the aqueous coating liquid coated may be suitably within the range of 2 to 10 g/m2 as the coated amount on drying and, if it is less than 2 g/m2, the coating will not function as the coated layer. In other words, when the coated amount is less than 2 g/m2, the ink colliding against the recording surface will be feathered along the fibers to be disturbed in dot shape, and at the same time the dye will be penetrated deep into the inner portion of the paper, whereby coloring density of the image will be lowered. On other hand, if the coated amount exceeds 10 g/m2, the merit of making the sizing degree of the substrate paper 0 to 15 sec.
• the recording paper is dried according to the drying method known in the art such as drying by hot air drying furnace, drying drum, etc. to provide a recording paper.
• the drying method known in the art such as drying by hot air drying furnace, drying drum, etc. to provide a recording paper.
• surface smoothening by super calendering may be also performed.
• the recording paper of the present invention having a Stöckigt sizing degree of 0 to 15 sec. and a basis weight of 90 to 200 g/m2 is obtained, but more preferably the Stöckigt sizing degree is in the range of 0 to 10 sec., optimally 0 to 5 sec. and the preferable range of the basis weight is in the range of 90 to 160 g/m2.
• the stiffness of the recording paper obtained is weak to pose a problem in carriage characteristic and or lack ink absorption capacity as the recording paper, whereby the printing portion may cause cockling or back-through, thus causing various problems as described above.
• the recording paper of the present invention which contains a large amount of a silicon containing type pigment with high ink absorbing capacity in the surface layer of the recording paper, has high probability of the ink droplets being trapped and absorbed by the pigment, and therefore feathering and diffusion of the ink can be inhibited, whereby it may be considered that dot shape is improved and also the coloring density enhanced.
• the substrate paper itself has ink absorptivity, the ink can be rapidly absorbed into the recording paper, whereby there is no such phenomenon such as flow-out or feathering of ink even when inks with different colors may be attached on one site within a short time, and therefore recorded images with excellent color forming characteristic can be obtained.
• the fibrous material on the surface of the substrate paper will not be completely covered with the silicon containing type pigment in the aqueous coating liquid, and the recording paper surface is under the state where the silicon containing type pigment and the fibrous material are mixed with each other.
• the recording paper has the sufficient characteristics as the ink jet recording paper, but also it has a texture approximate to plain paper with little powder drop-off from the coated layer as additional advantage.
• a hand-made sheet with low sizing degree was controlled to the basis weight as shown below, and to the substrate paper was applied by coating an aqueous coating liquid with the following composition at the coating amounts on drying, respectively, followed by drying at 120 °C for 5 minutes, to obtain recording media of the present invention and for comparative purpose.
• the basis weight of the substrate paper, coating amounts on drying of coating layers, the basis weights of recording media and Stöckigt sizing degrees of recording media are shown in Table 1.
• a wood free paper with a basis weight of 80 g/m2 was coated with the above coating liquid at a coating amount on drying of 6 g/m2, dried similarly as above to obtain a recording medium K for comparison.
• the recording medium obtained had a Stöckigt sizing degree of 25 sec.
• Table 1 Sample No. Basis weight of Substrate Paper Amount of Coating on Coating Layer Basis weight of Recording Paper Stöckigt Sizing Degree of Recording Paper A 40g/m2 6g/m2 46g/m2 4sec. (Comparative example 1) B 63 2 65 4sec. (Comparative example 2) C 63 6 69 4sec.
• Example 6 On the substrate paper used in Example 1, the compositions shown below were used, following otherwise the same procedure as in Example 1, recording media L and M of the present invention were obtained. Similarly, according to the same procedure as in Example 3 except for using the compositions shown below on the same substrate paper used in Example 3, recording media N and O of the present invention were obtained. Then, by use of these recording media, recording was performed in the same manner as in Example 1 and evaluation was performed. The results are shown in Table 3.
• Example 6 Example 7

Landscapes

• Paper (AREA)
• Ink Jet Recording Methods And Recording Media Thereof (AREA)
• Ink Jet (AREA)
• Polarising Elements (AREA)
• Particle Formation And Scattering Control In Inkjet Printers (AREA)
• Medicinal Preparation (AREA)
• Color Printing (AREA)
• Meat, Egg Or Seafood Products (AREA)
• Decoration Of Textiles (AREA)
• Credit Cards Or The Like (AREA)

Priority Applications (1)

Applications Claiming Priority (2)

Publications (2)

Family

ID=17796560

Family Applications (1)

Country Status (11)

Families Citing this family (11)

Family Cites Families (10)

• 1987
  • 1987-11-20 JP JP62293579A patent/JPH0717085B2/ja not_active Expired - Fee Related
• 1988
  • 1988-04-29 EP EP88303892A patent/EP0317046B1/en not_active Expired - Lifetime
  • 1988-04-29 ES ES88303892T patent/ES2042739T3/es not_active Expired - Lifetime
  • 1988-04-29 DE DE88303892T patent/DE3882656T2/de not_active Expired - Fee Related
  • 1988-04-29 AT AT88303892T patent/ATE91976T1/de not_active IP Right Cessation
  • 1988-05-04 NO NO881948A patent/NO174434C/no not_active IP Right Cessation
  • 1988-05-04 AU AU15553/88A patent/AU599483B2/en not_active Ceased
  • 1988-05-04 FI FI882092A patent/FI94542C/fi not_active IP Right Cessation
  • 1988-05-05 DK DK244588A patent/DK171242B1/da not_active IP Right Cessation
  • 1988-05-11 CA CA000566471A patent/CA1333033C/en not_active Expired - Fee Related
• 1994
  • 1994-01-13 HK HK37/94A patent/HK3794A/xx not_active IP Right Cessation

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