1、Designation: D6846 02 (Reapproved 2012)Standard Practice forPreparing Prints of Paste Printing Inks with a Printing Gage1This standard is issued under the fixed designation D6846; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the
2、 year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This practice covers the procedure for preparing labo-ratory prints of paste inks using a printing gage in co
3、njunctionwith a flat-bed proof press.1.2 This practice is applicable to the preparation of solid-area prints by direct letterpress or by dry offset on a flatsubstrate such as paper, paperboard, or metal.1.3 This practice is applicable primarily to lithographic andletterpress inks that dry by oxidati
4、on or penetration. With theaddition of appropriate drying or curing equipment, it is alsoapplicable to other paste ink systems such as heat-set orenergy-curable.1.4 The instructions in this practice are intended to mini-mize the within-print and among-operator variability inherentin hand operations.
5、1.5 This practice features built-in ink film thickness control.It does not measure the film thickness transferred to the print;however, film thickness equivalence may be evaluated byvisual or instrumental comparisons of optical density.1.6 Values stated in SI units are to be regarded as thestandard.
6、 The values given in parentheses are for informationonly.1.7 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bili
7、ty of regulatory limitations prior to use. Specific precau-tions are given in Section 7.2. Referenced Documents2.1 ASTM Standards:2D1316 Test Method for Fineness of Grind of Printing InksBy the NPIRI GrindometerD6073 Test Method for Relative Setting of Heatset PrintingInksD6487 Practice for Preparin
8、g Prints of Paste Printing InksUsing a Hand Operated Laboratory Flat-Bed Press3. Summary of Practice3.1 The printing gage is inked by a drawdown technique; adouble drawdown is recommended to minimize scratches andimprove print appearance.3.2 The inked gage is placed in the bed of the proof pressfrom
9、 which the regular printing plate has been removed.3.3 To make a letterpress print, the appropriate stock isattached to the impression (blanket) cylinder, which is rolledonce over the inked gage. To make a dry offset print, the stockis clipped onto the impression plate and the blanket cylinder isrol
10、led over the inked printing gage two to four times followedby once over the stock.3.4 Two-color prints may be prepared by utilizing two inkedgages in the bed of an offset proofing press.4. Significance and Use4.1 Laboratory proofing of inks is necessary to establish areproducible prediction of print
11、 appearance and performanceproperties, most of which are highly sensitive to ink filmthickness. The apparatus described in this practice has foundwide use for routine control proofing because it provides aneconomical method for producing reasonably large prints atfilm thicknesses comparable to those
12、 obtained on productionpresses.4.2 A unique advantage of printing gages is that, dependingon the design selected, prints can be produced at a range oftapered film thicknesses or at several levels of uniformthicknesses in a single proofing. Because of the built-in filmthickness control, ink metering
13、is not necessary. Relativelysmall quantities of test samples are used, and less than twominutes are required to ink a gage, pull a letterpress print, andclean up. In addition, problems due to ink distribution systemsare eliminated, two inks may be proofed at the same time, andmulti-color printing is
14、 possible.4.3 This practice does not duplicate the dynamics of a highspeed press, nevertheless, it is useful for quality control and forspecification acceptance between the producer and the user.1This practice is under the jurisdiction of ASTM Committee D01 on Paint andRelated Coatings, Materials, a
15、nd Applications and is the direct responsibility ofSubcommittee D01.56 on Printing Inks.Current edition approved June 1, 2012. Published August 2012. Originallyapproved in 2002. Last previous edition approved in 2007 as D6846 02 (2007).DOI: 10.1520/D6846-02R12.2For referenced ASTM standards, visit t
16、he ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959.
17、United States15. Apparatus5.1 Printing Gage,3consisting of a type-high (approximately23.3 mm, 0.918 in.) block of steel, the top surface of whichcontains precision-machined channels that may be tapered indepth similar in principle to the grind gages described in TestMethod D1316. Alternatively, the
18、channels may be uniform indepth at one or more levels. See Fig. 1 for schematic diagramsof the two types of gages. A description of popular models isgiven in Table 1.5.2 Drawdown Blade,3having a length sufficient to span thewidth of the printing gage being used.5.3 Flat Bed Proof Press, with a bed w
19、ide enough toaccommodate the printing gage. If proofing by dry offset isspecified, the cylinder of the press must be capable of makingtwo revolutions down the length of the bed, as in PracticeD6487.5.4 Ink Knife, small.5.5 Accelerated Drying Equipment (Optional), for example,source of heat as in Tes
20、t Method D6073 or energy-curing, asappropriate to the system.5.6 Print Quality Measuring Equipment (Optional), as de-scribed in Practice D6487 or as agreed upon between producerand user.6. Materials6.1 Reference Standard (Optional), such as an ink sample,reference print, or a target level of quality
21、 attribute.6.2 Printing Substrate, cut to slightly more than the dimen-sions of the gage top cited in Table 1.6.3 Shim Stock, metal or plastic, the same size as theprinting gage and 0.5 or 1 mil in thickness.6.4 Wash-up Materials, including lint-free rags or tissue andan appropriate solvent.6.5 Grea
22、se, to protect top face of printing gage when not inuse.7. Hazards7.1 WarningSince solvents may be hazardous to the skinand eyes, wear rubber gloves and safety glasses during cleanupto avoid solvent contact with skin and eyes. In case of contact,wash skin with water; flush eyes for 15 min with water
23、 and calla physician. See suppliers Material Safety Data Sheets forfurther information on each solvent used.7.2 Equipment Cautions:7.2.1 Avoid any operation that will scratch or damage theprinting gage and the blade. Refer to Test Method D1316 fortheir care and for checking wear on the blade.7.2.2 W
24、hen proofing by the dry offset process, avoid anyoperation that will damage the impression blanket. If additionalprinting pressure is found necessary during the setup process,3The sole source of supply of the apparatus known to the committee at this timeis Precision Gage and Tool Co., 375 Gargrave R
25、d., Dayton, Oh 45449. If you areaware of alternative suppliers, please provide this information to ASTM Interna-tional Headquarters. Your comments will receive careful consideration at a meetingof the responsible technical committee,1which you may attend.FIG. 1 Schematic Diagram of Printing Gages (n
26、ot drawn to scale)TABLE 1 Popular Models of Printing GagesAModelNumberof PathsDimensionsof EachPathDimensionsof GageTopInk Film ThicknessMachined CalibratedBmm mm mils m mTapered Film ThicknessNPIRI-AC2 25 159 89 241 0-1.0 0-25 0-20NPIRI-B 2 38 159 114 241 0-0.6 0-15 0-12Uniform Film Thickness, Sing
27、le DepthWarren-2 1 76 165D102 165D0.3 712 6Warren-3 1 76 165D102 165D0.4 10 8Warren-4 1 76 165D102 165D0.5 1212 10Warren-5 1 76 165D102 165D0.6 15 12Huber-2 1 63 152 89 152 0.8 20 16BSI-10 2 51 165E140 165E0.4 10 8Lindner 2 51 165E140 165E0.6 15 12Uniform Film Thickness, Three DepthsFFPBAA-C 3 38 10
28、2 165 102 0.20.40.65101548126960-1 3 38 102 165 102 0.20.30.45712104686960-2 3 38 102 164 102 0.50.60.71212151712101214Combination Uniform and Tapered Film Thickness6401 2 51 20351 159153 203 0.60-0.6150-15120-12AAll models have paths ca. 23.3 mm (0.918 in.) high, parallel to bottom face.BCalibrated
29、 microns listed are based on 80 % path fillage for normal paste inks.Fillage for thinner inks is less.CThis model serves as a type-high grindometer in Test Method D1316.DAlso available in a 190 mm length.EAlso available in a 203 mm length.FEach path has a uniform depth, but the depth is different in
30、 each path. Any othercombination may be ordered.D6846 02 (2012)2be especially careful to raise the plate a minimum amount.Since indentation by the printing gage on the blanket is apossibility in any event, it may be useful to dedicate a blanketto each gage being utilized. A dedicated blanket is esse
31、ntial forproofing with energy-curable systems.8. Test Specimen8.1 Approximately 1 to 2 mL of ink specimen is sufficient tofill the paths of a typical printing gage. When taking aspecimen from the sample container, push aside the top layerand take the sample from below so as to avoid skin or surfaced
32、ust.9. Procedure for Proofing9.1 Ink the Printing Gage:9.1.1 Clean the gage and scraper with appropriate solventand lint-free wiping materials. Set the gage in a positioncomfortable to the operator, such as on the bed of the press ora sturdy bench top.9.1.2 Using an ink knife, place a small quantity
33、 of test ink ineach path about 15 mm in from the far end of each path.Depending on test instructions, two inks may be placed in thesame channel or in separate channels of a multi-path gage. Inthis case, use separate ink knives for the two inks.NOTE 1If ink is placed at the very end of the path(s), i
34、t is virtuallyimpossible to avoid a thick ridge of ink at that end of the gage. A “messy”print will result.9.1.3 Hold the drawdown blade with the thumb and nexttwo fingers. Place in a vertical position behind the ink on theplate. Using the third finger as a loose guide along side of theplate, draw t
35、he ink down the plate slowly, steadily and withadequate pressure. At the end of the drawdown, come off theplate with a downward motion but without hitting the pressbed. The natural inclination to come off the plate with anupward motion results in a thick ridge of ink on the gage and,in turn, on the
36、print.9.1.4 Examine the drawdown(s). If there are scratches in theink film(s) that will interfere with the final purpose of the print,they may be minimized or eliminated altogether by making adouble drawdown in the following manner. At the end of thefirst drawdown, hold the blade in the left hand. W
37、ith the righthand, turn the plate around 180. Gently scrape off excess inkfrom the blade and transfer to the plate as in 9.1.2 (about 15mm in from the far end of each path). Using the clean side ofthe blade, draw down the ink as 9.1.3.NOTE 2It should be pointed out that the milled depths of most pri
38、ntinggages are of the same orders of magnitudes as grind gages. Hence,scratches in the first drawdown may be unavoidable. The second draw-down has been found to fill the scratches but not to alter the ink filmthickness in the channel.9.2 Printing by Direct Letterpress:9.2.1 Remove the normal inking
39、plate and other pressfurniture from the bed of the proof press.9.2.2 Center the inked gage in the press bed next to the deadline bar (the plate bracket closest to the impression cylinder) sothat the paths run parallel to the axis of the cylinder. See Fig.2. A plate bracket or other press furniture o
40、n the opposite sideof the plate (corresponding to the trailing edge of the print) andthe guide tracks are not necessary but may be left in place.9.2.3 Mount the sheet of the test substrate directly on theimpression (blanket) cylinder. Engage the cylinder and turn thehandle one revolution as fast as
41、possible.9.2.4 Remove the print and examine. If contact appearsinsufficient, add a minimum of shim stock below the gageand/or, if possible, alter the amount of packing on the cylinder.Repeat 9.2.2 and 9.2.3 with a freshly inked gage.9.3 Printing by Dry Offset:9.3.1 This operation requires a flat bed
42、 press (Fig. 3)capable of making two revolutions. Remove only the regularinking plate from the bed, and if necessary, change the blanket(see 7.2.2).9.3.2 Ink the printing gage as per 9.1 and center in the pressbed as in 9.2.2. Clip the test substrate onto the flat impressionplate.FIG. 2 Printing Gag
43、e in the Bed of an Offset Color Proof PressSet Up for Letterpress PrintingFIG. 3 Printing Gage in the Bed of an Offset Color Proof PressSet Up for Dry Offset PrintingD6846 02 (2012)39.3.3 Ink the blanket by engaging the cylinder and makingonly one revolution, during which it passes over the printing
44、gage. Disengage the cylinder and return (blanket is inked inforward motion only). Repeat the number of times required toink the blanket properly, usually two to four. If no ink at all istransferred to the blanket, raise the plate with a minimum ofshim stock.9.3.4 After the blanket is properly inked,
45、 make the printingpass by engaging the cylinder and rolling it over the gage andthe substrate in one rapid continuous motion.9.4 Multi-Color Printing:9.4.1 It is possible to study wet trapping of two inks byutilizing two inked printing gages in the bed of an offset press.To illustrate the effects of
46、 ink film thickness, a multi-pathuniform film thickness gage is utilized (such as FPBAA-C or#6960-1 in Table 1); however it is recommended that only thetwo lower depths be inked, giving a print with four squares:four and eight (or six) microns of the second color over fourand eight (or six) microns
47、of the first color.9.4.2 Remove all press furniture from the bed of an offsetcolor proof press.9.4.3 Using the procedure in 9.1, draw down (double ifneeded) the first ink in the path(s) of a printing gage. Drawdown (double if needed) the second ink in the paths of anothergage.9.4.4 Place the gage wi
48、th the first ink in the bed of the pressnext to the deadline bar. Set the gage with the second ink in theplace formerly occupied by the impression plate; the orienta-tion of the second gage should be 90 from the first gage.9.4.5 Attach the appropriate stock to the blanket cylinder,engage the cylinde
49、r, and roll it over the two gages in one rapidcontinuous motion.10. Post Press Operations10.1 Immediately after the print is made, remove from thepress and perform specified tests on the wet print, the print airdried for a specified time (usually 24 to 48 h), or the print driedby running through the Sinvatrol as in Test Method D6073 orthrough UV lamps or other appropriate apparatus.10.2 As soon as possible, clean up the printing gage andblade prior to making additional prints. If long-time storage isanticipated, it
