Classifications

• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
  • G01N33/00—Investigating or analysing materials by specific methods not covered by groups G01N1/00 - G01N31/00
  • G01N33/26—Oils; Viscous liquids; Paints; Inks
  • G01N33/32—Paints; Inks
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
  • G01N13/00—Investigating surface or boundary effects, e.g. wetting power; Investigating diffusion effects; Analysing materials by determining surface, boundary, or diffusion effects
  • G01N13/02—Investigating surface tension of liquids
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
  • G01N13/00—Investigating surface or boundary effects, e.g. wetting power; Investigating diffusion effects; Analysing materials by determining surface, boundary, or diffusion effects
  • G01N13/02—Investigating surface tension of liquids
  • G01N2013/0208—Investigating surface tension of liquids by measuring contact angle

Definitions

• the present invention is generally directed toward improved methods for determining the receptivity of ink to substrates based on the force needed to extract a sample of the substrate in contact with an ink. More particularly, the present invention provides a method for predicting multicolor ink jet printability on surfaces of substrates by contact angle measurement alone without having to print on the surface.
• compositions suitable as coating surfaces for printing are the necessity of having to coat large samples of paper (or other substrates), actually print on the samples and subsequently evaluate the quality of the printed samples for print resolution and density. While the foregoing is a straightforward and reliable approach in selecting suitable coating compositions, it is somewhat time consuming, particularly with regard to sample preparation and analysis of the image after it has been printed.
• U.S. Patent No. 4,446,174 ('174 patent) describes a method for producing a recorded image on an image-receiving sheet with a jet of aqueous ink.
• the ink jet is projected onto the sheet comprising a surface layer containing a pigment.
• the surface layer adsorbs a coloring component present in the ink.
• the invention purports that when the surface layer contains a pigment and adhesive with an R f value (ratio of travelling distance in the pigment coating of dye to that of the solvent in the aqueous ink) of 0.59, a suitable combination of pigment coating and aqueous ink has been found.
• the principle under which this method operates is that of paper chromatography. -2-
• a disadvantage of the method described in the '174 patent is that to get an R f number, the coating has to be applied to a glass plate. This means that paper variables are not accounted for in the test. Thus, it is possible that the method of the '174 patent will predict a coating having an acceptable R f number but when applied to a piece of paper or media the results are different.
• the present invention offers an alternate method for determining the proper pigment coating and/or substrate compositions for use with multi-colored aqueous inks as hereinafter described which actually tests the ink's receptivity with the coating in conjunction with the substrate or the substrate alone.
• the present invention relates to methods for determining a surface's receptivity to ink comprising the steps of: (a) providing a sample of the surface;
• the invention is concerned with a method for determining a suitable surface coating composition for receiving multicolored inks comprising the steps of:
• the invention relates to a method for determining a suitable ink composition in response to a surface comprising the steps of:
• Advantages of the methods of this invention include providing a quick, and reliable method for screening coating compositions suitable for use in printing applications.
• the method may be used to adjust the composition of a dye or ink in response to a surface or as a method of determining a suitable substrate composition in response to a dye or ink. -4.
• Figure 1 is a schematic of a device useful in the practice of this invention.
• the methods of this invention relate to an improved tool for quickly and reliably screening suitable printing surfaces and printing inks which result in exceptional printed image characteristics of high density and high definition.
• the present invention will become more apparent from the following definitions and accompanying discussion.
• Substrate - refers to media capable of being printed upon, such as paper, cardboard, fabric, canvas, polymers such as vinyl, acetate, and mylar.
• Surface - refers to coated or uncoated substrate surfaces.
• Contact Angle - refers to the tangent angle of a liquid to a surface.
• the liquid can spread across the surface (low contact angle) or be repelled by the surface (high contact angle).
• Contact angles may be calculated from dynamic contact angles measured during immersion and removal of a surface from a liquid during a measured time period. Too much deviation in contact angle will impart either loss of density or excessive bleed. Additionally, it is desirable to control the value of the contact angle between 60° and 110°, preferably between 70° and 100°, most preferably between 70° and 90°. Contact angles less than 70° will tend to have poorer image density. Contact angles greater than 100° will tend to have greater bleed. The intent is to have similar contact angle -5-
• Preset Deviation - refers to an acceptable variation in the measured or calculated force between the ink and surface which gives the desired printed quality in terms of color density and color definition. Thus, in some applications, the required variation may be quite small in order to achieve a balance of high density and high resolution.
• acceptable printed quality is achieved when the deviation in terms of contact angle is not more than ⁇ 10, preferably not more than ⁇ 5, most preferably not more than ⁇ 3 degrees from the numeric average of the measured contact angles.
• the present invention is based on identifying coating compositions or inks which respond equally in terms of the individual ink's affinity to a surface. For example, finding a coating composition that responds equally to the different surface tensions (a measure of the force or affinity of the ink to a surface) of the four colors used in ink jet printing would result in exceptional image density and definition. Too much deviation in surface tension among the inks in response to the coating surface will impart either a loss of image density or excessive bleed (loss of definition). Thus, it is desirable to have the various ink surface tensions near the same value in order to achieve a similar affinity to the coating composition.
• the affinity of the ink(s) to the surface is expressed in terms of the contact angle between the ink(s) and the surface.
• the contact angles may be determined from measurement of a dynamic contact angle.
• Commercially available dynamic contact angle measurement devices may be used such as the Cahn DCA 315 available from Cahn Instruments, Madison, Wl. This device contains the instrument software "WinDCA" copyrighted 1996 which calculates a contact angle based on the immersion and removal of a surface sample into a liquid a distance of 4mm in 25 seconds from the point of contact. These parameters can be changed.
• FIG. 1 depicts a simplified schematic of the Cahn DCA 315 apparatus and a short description of its operation follows.
• a 1" x 1" square SAMPLE (1) is secured to an ARM (2) which in turn is connected to a FORCE MEASUREMENT DEVICE (3).
• a BEAKER (4) containing the TEST INK (5) is elevated manually until the TEST INK (5) is in close proximity to the SAMPLE (1). Typically, this distance is less than 0.5 cm.
• the instrument program in the device is run which raises the TEST INK (5) in order to contact and immerse the SAMPLE (1). Once contact is made between the SAMPLE (1) and the surface of the TEST INK (5), the change in force associated with the contact is made.
• the change in force over a specified distance indicates the affinity or repulsion of the TEST INK (5) for the SAMPLE (1).
• the program measures the force during retraction of the SAMPLE (1) from the TEST INK (5). All of the measurements are then used to calculate the dynamic contact angle for the TEST INK (5).
• the affinity of these prepared colors to three surfaces were determined.
• the surfaces tested were a uncoated piece of bond paper (Base Sheet), a commercially available inkjet premium coated sheet (Premium Sheet) and an experimental coated sheet (Experimental Sheet).
• the DOS based HP Deskjet printer Dietzgen test pattern generates areas for analysis for both color density and definition.
• Color densities are measured with a COSAR 200 densitometer with a polarized filter. Five readings are taken for each color from the approximately 1 " x 1 " color block generated by the printers. The color density readings are taken at four corners and the center of the color square, averaged and then recorded.
• the solid color blocks are used for all the primary and combination colors. Ratings are determined by "Good”, “Slight”, and “Moderate”. The distinction for each relates to the color block edge sharpness, non-printed line sharpness (within the color blocks), in both horizontal and verticle directions. However, the test pattern has additional areas to determine black color definition. It has blocks for tone comparison. Black blocks of 3 , 34, and full tone also indicate definition. The better the tone distinction the better the definition.
• the area of the pattern for fine definition is such that eight lines are produced, both horizontally and vertically, from a common point. They separate approximately 1 degree from each other over a distance of 1.70 inches. Therefore, the closer to the focal point each line is identifiable, the better the definition.
• the ratings are comprised of each of these areas and given an overall definition rating.
• the contact angle results of Table 1 order the SHEETS in the following order from lowest to highest contact angle for the color Cyan: PREMIUM (79.1), EXPERIMENTAL (81.3) and BASE (111.2).
• the color density results of TABLE 2 for these SHEETS have the corresponding order for color density from lowest to highest color density: BASE (1.32), EXPERIMENTAL (1.51 ), and PREMIUM (1.65).
• the color definition results are correlatable by comparing the contact angle deviations of Table 1 to the observed color definition results of Table 2.
• the color Cyan has the following order in terms of measured contact angle deviations from lowest to highest: EXPERIMENTAL (+0.05), PREMIUM (+2.28), and BASE (+17.35).
• the color definition results report EXPERIMENTAL and PREMIUM as GOOD and the BASE as SLIGHT. Therefore, one observes that color definition is adversely affected when contact angle deviations are large. The results for all the other colors correspondingly demonstrate this trend. -10-

Landscapes

• Chemical & Material Sciences (AREA)
• Health & Medical Sciences (AREA)
• Life Sciences & Earth Sciences (AREA)
• Immunology (AREA)
• Analytical Chemistry (AREA)
• Biochemistry (AREA)
• General Health & Medical Sciences (AREA)
• General Physics & Mathematics (AREA)
• Physics & Mathematics (AREA)
• Pathology (AREA)
• Engineering & Computer Science (AREA)
• Food Science & Technology (AREA)
• Medicinal Chemistry (AREA)
• Inks, Pencil-Leads, Or Crayons (AREA)
• Printing Methods (AREA)
• Spectrometry And Color Measurement (AREA)

Applications Claiming Priority (3)

Publications (1)

Family

ID=22101766

Family Applications (1)

Country Status (6)

Families Citing this family (4)

Family Cites Families (2)

• 1999
  • 1999-04-13 EP EP99921387A patent/EP1092143A1/en not_active Withdrawn
  • 1999-04-13 BR BR9910163-7A patent/BR9910163A/pt not_active Application Discontinuation
  • 1999-04-13 WO PCT/US1999/008271 patent/WO1999057539A1/en active IP Right Grant
  • 1999-04-13 CZ CZ20004053A patent/CZ20004053A3/cs unknown
  • 1999-04-13 AU AU38614/99A patent/AU758245B2/en not_active Ceased
  • 1999-04-13 CN CN 99805742 patent/CN1300363A/zh active Pending

Non-Patent Citations (1)

Also Published As

Similar Documents

Legal Events