JP2013129098A - High definition printer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a printer which can continuously form a high-quality printing pattern, in the printer used in gravure offset printing.SOLUTION: The offset printer 10 comprises an intaglio in which a printing pattern is formed and a blanket 16 for accepting an ink 14 filled in the intaglio, and prints the printing pattern by transferring the ink 14 accepted by the blanket 16 to a base material 18 to be printed. The blanket 16 is bridged between a plurality of rollers including a sending roller 26-1 and formed into an endless belt shape, and circulates in conjunction with the rotation of the sending roller 26-1. An accepting position A for accepting the ink 14 of the blanket 16 from the intaglio and a transfer position T for transferring the accepted ink 14 to the base material 18 to be printed are set within a range R in which the blanket 16 continuously and internally contacts with the sending roller 26-1, and the internally-contacting transfer position T is formed at the rear of the circulating direction of the blanket 16 rather than the accepting position A.

Description

  The present invention relates to a printing apparatus used for gravure offset printing, and more particularly to a printing apparatus that can be advantageously used for printing fine fine line patterns such as printed wiring boards.

  Information display devices such as wiring boards for electronic components and electronic paper are provided with wirings and electrodes having precise fine line patterns on a substrate used for the substrate or the device. Conventionally, a photolithography method, a screen printing method, a gravure printing method, a gravure offset printing method, or the like is used for printing a fine line pattern on the substrate. And printing methods such as gravure printing method and gravure offset printing method do not require complicated processes, and are printing methods that can perform printing of large area fine line patterns at low cost. This is advantageous in that a finer and more accurate fine line pattern can be printed.

  FIG. 6 is a schematic side view for explaining a conventional gravure offset printing method. As illustrated, a printing apparatus 60 used for gravure offset printing includes a plate cylinder 62, a blanket roll 64 made of silicon rubber facing the plate cylinder 62, an impression cylinder roll 66 facing the blanket roll 64, and a doctor blade 68. . Then, the blanket roll 64 receives the ink 70 filled in the concave portion 62 a of the plate cylinder 62, and transfers it to the thin film-like substrate 72 to be inserted between the blanket roll 64 and the impression cylinder roll 66. As a result, the printing pattern of the plate cylinder 62 is printed on the substrate 72 to be printed.

  However, when printing is performed by the printing apparatus 60 used in the gravure offset printing method, the ink 70 is successfully transferred from the blanket roll 64 to the substrate 72 to be printed at the start of printing. There may be a problem that a part of the blanket roll 64 remains and the quality of the print pattern is deteriorated. This is because, during continuous printing, the blanket roll 64 absorbs the solvent in the ink 70 received from the plate cylinder 62 and swells, and the wettability between the blanket roll 64 and the ink 70 changes compared to when printing starts. It is thought that this is a phenomenon caused by this.

  In Patent Document 1, in order to prevent the deterioration of the print quality, a solvent absorber made of silicon rubber is brought into contact with the blanket roll after the ink is transferred to the substrate to be printed, and the ink solvent absorbed by the blanket roll is removed. A method of removing is disclosed.

JP 2000-158633 A

  However, according to the removal method of the ink solvent in which the solvent absorber is brought into contact with Patent Document 1, the ink solvent once absorbed by the blanket roll is divided into the blanket roll and the solvent absorber and is transferred by pressure bonding with the solvent absorber. , The amount of both reaches equilibrium. This will remove the ink solvent from the blanket roll, but the solvent absorber will not be able to absorb more ink solvent than the amount that has reached the equilibrium between them, and therefore, depending on the method, the blanket roll will absorb. There is a possibility that the used ink solvent cannot be removed sufficiently.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a printing apparatus that is used for offset printing and in which the deterioration of the quality of a print pattern during continuous printing is prevented.

The above object has an intaglio in which a printing pattern is formed and a blanket for receiving ink filled in the intaglio, and transferring the ink received by the blanket to a substrate to be printed. An offset printing apparatus for performing printing, wherein the blanket is an endless belt stretched between a plurality of rollers including a rotating feed roller, and circulates in conjunction with the rotation of the feed roller. Configured, a receiving position for receiving the ink of the blanket from the intaglio, and a transfer position for transferring the received ink to the substrate to be printed are set within a range where the blanket is inscribed in the feeding roller, Within the inscribed range, the transfer position is provided behind the receiving position with respect to the blanket rotation direction. It is achieved by the offset printing apparatus according to claim.
As a result, the ink is received from the intaglio and the transferred ink is transferred to the substrate to be printed within a range in which the blanket is inscribed in the feed roller, and the blanket has a plurality of times until the next ink is received from the intaglio. It circulates the distance reciprocating between rollers over a fixed time. Therefore, the solvent component in the ink absorbed by the blanket can be volatilized during the circulation, and the solvent component can be removed from the blanket. Therefore, the wettability of the blanket to the ink is always constant at the ink receiving position from the intaglio. Further, it is possible to prevent the quality of the print pattern from being deteriorated during continuous printing.

  In addition, when the blanket has a substantially cylindrical shape as in the prior art, if ink is volatilized and removed by heating the blanket surface, ink is received from the plate cylinder on the same circumference of the blanket. The part, the part to transfer the ink to the substrate to be printed, and the part to be heated are arranged. Therefore, these parts are structurally arranged close to each other, and heat from the heating part is transmitted from the plate cylinder to the part that receives the ink and the part that transfers the ink to the printing substrate, and the printing substrate As a result, even the ink to be transferred is volatilized, and the quality of the print pattern is lowered.

  However, if the blanket is configured as described above, if the blanket is at a position away from the range inscribed in the feed roller, the heat generated by heating is not transmitted to the ink receiving part and the transfer part, and the ink received by the blanket Therefore, it is possible to provide means for promoting volatilization removal of the solvent component in the ink by heating (for example, a dryer or an electric heater) in the blanket.

Preferred embodiments of the offset printing apparatus of the present invention are as follows.
(1) The substrate to be printed is a long thin film, the intaglio is a substantially cylindrical plate cylinder, and the transfer surface of the substrate to be printed is pressed against the blanket at the transfer position. The plate cylinder, the blanket, and the impression cylinder circulate in conjunction with each other.
(2) In a triangle formed by connecting the receiving position, the shaft center of the feed roller, and the transfer position, an inner angle at the shaft center of the feed roller is 45 to 170 °.
(3) Volatilization removal promoting means for promoting volatilization removal of the solvent component in the ink absorbed by the blanket is provided outside the range where the blanket is inscribed in the feed roller.

  According to the printing apparatus of the present invention, since the solvent component in the ink absorbed by the blanket can be effectively volatilized and removed, it is possible to provide a printing apparatus in which the deterioration of the quality of the printing pattern during continuous printing is prevented. . Therefore, it is possible to provide a substrate having a fine and high-precision fine line pattern used in an information display device such as an electronic component wiring board or electronic paper by a simple and low-cost method.

1 is a schematic side view of an offset printing apparatus according to an embodiment of the present invention. (A) Similarly, it is a schematic side view which shows the state which the blanket in the offset printing apparatus received the ink from the plate cylinder. (B) Similarly, it is a schematic side view showing a state where ink is transferred from a blanket to a substrate to be printed in an offset printing apparatus. Similarly, it is a schematic side view of an offset printing apparatus provided with volatilization removal promoting means. Similarly, it is a schematic side view which shows the other aspect of the blanket in an offset printing apparatus. It is a schematic side view of the offset printing apparatus which concerns on 2nd Embodiment of this invention. It is a schematic side view of the offset printing apparatus using the conventional blanket roll.

  Next, embodiments of the present invention will be described in detail with reference to the drawings.

(First embodiment)
An offset printing apparatus that has an intaglio in which a printing pattern is formed and a blanket that receives ink filled in the intaglio, and that prints the printing pattern by transferring the ink received by the blanket to a substrate to be printed 1st Embodiment is described with reference to FIGS. 1-3 for the example of the offset printing apparatus using a elongate thin-film-form to-be-printed base material.

  FIG. 1 is a schematic side view of an offset printing apparatus according to an embodiment of the present invention. As shown in the drawing, an offset printing apparatus 10 according to the present embodiment includes a plate cylinder 12 that is an intaglio plate on which a printing pattern is formed, a blanket 16 that contacts the plate cylinder 12 and receives ink 14 filled in the intaglio plate, A printing substrate 18 onto which the ink 14 on the blanket 16 is transferred, and a substantially cylindrical pressure drum 20 that presses the printing substrate 18 against the blanket 16 are provided. Details of each component will be described below.

  The plate cylinder 12 is a rotating body configured as an intaglio plate having a printing pattern formed on a cylindrical surface. The plate cylinder 12 uses, for example, iron or aluminum as a base material, and has a cylindrical surface plated. Then, a recess 12a that can be filled with the ink 14 is provided on the plating, and finally the substrate 12 is printed by adjusting the shape, number, and arrangement of the recess 12a such as depth and width. A print pattern can be selected. The printing pattern is, for example, a wiring pattern on a wiring board of an electronic component or a pattern electrode applied to a base material of an information display device such as electronic paper.

  The vicinity of the lower end portion of the plate cylinder 12 is immersed in the ink 14 stored in the ink storage tank 22, and the ink 14 is sequentially filled in the recesses 12 a by the rotation of the plate cylinder 12. At this time, the ink 14 adhering to the peripheral surface of the plate cylinder 12 beyond the amount filled in the concave portion 12a is scraped off from the peripheral surface of the plate cylinder 12 by a doctor blade 24 having a well-known configuration. The ink 14 is filled into the recess 12a.

  The ink 14 may be any liquid ink material. However, when forming a pattern electrode of an information display device such as a wiring pattern on an electronic component wiring board or electronic paper, the conductive particles are particularly useful. It is preferable to use a conductive ink containing a binder resin.

  Examples of the conductive particles used in the conductive ink include aluminum, nickel, indium, chromium, gold, vanadium, tin, cadmium, silver, platinum, copper, titanium, cobalt, lead and other metals, and alloys thereof; or Indium oxide, tin oxide, zinc oxide, indium oxide-tin oxide (ITO, so-called indium-doped tin oxide), tin oxide-antimony oxide (ATO, so-called antimony-doped tin oxide), zinc oxide-aluminum oxide (ZAO; so-called aluminum dope) Examples thereof include conductive oxides such as zinc oxide), and conductive polymer doping materials such as polyacetylene, polyparaphenylene, polyaniline, polythiophene, polyisothionaphthene, polypyrrole, and polyparaphenylene vinylene. These may be used alone or in combination of two or more.

  Examples of the binder resin used in the conductive ink include acrylic resin, polyester resin, epoxy resin, urethane resin, phenol resin, maleic acid resin, melamine resin, urea resin, polyimide resin, and silicon-containing resin. . Furthermore, it is preferable that it is a thermoplastic resin among these resins.

  The conductive ink further contains a solvent in order to adjust to an appropriate viscosity and drying property. Solvents include alcohols such as hexanol, octanol, nonanol, decanol, undecanol, dodecanol, tridecanol, tetradecanol, pentadecanol, stearyl alcohol, seryl alcohol, cyclohexanol, terpineol; ethylene glycol monobutyl ether (butyl cellosolve), ethylene glycol Examples include alkyl ethers such as monophenyl ether, diethylene glycol, diethylene glycol monobutyl ether (butyl carbitol), cellosolve acetate, butyl cellosolve acetate, carbitol acetate, and butyl carbitol acetate.

  The blanket 16 is an endless belt stretched between the feed roller 26-1 and the second roller 26-2, and circulates in conjunction with the rotation of the feed roller 26-1 in the direction of arrow 100. As a material of the blanket 16, a rubber material having elasticity is used. As this rubber material, NBR (nitrile rubber), EPDM (ethylene propylene rubber), silicon rubber, SBR (styrene butadiene rubber), UR (urethane rubber) can be used, and silicon rubber is particularly preferable. The total length of the blanket 16 is the time until the solvent in the ink 14 absorbed by the blanket 16 when receiving the ink 14 receives the ink 14 from the plate cylinder 12 again in relation to the rotational speed of the blanket 16. The length can be appropriately set so as to be volatilized and removed in the meantime.

  In the present embodiment, the substrate 18 to be printed is a long flexible thin film. Such a printing substrate 18 is, for example, a polymer film. Any polymer film may be used, but polyester such as polyethylene terephthalate (PET), acrylic resin such as polymethyl methacrylate (PMMA), polycarbonate (PC), polystyrene, cellulose triacetate, polyvinyl alcohol, polyvinyl chloride, and polychlorinated. Examples include vinylidene, polyethylene, ethylene-vinyl acetate copolymer, polyvinyl butyral, metal ion-crosslinked ethylene-methacrylic acid copolymer, polyurethane, cellophane and the like. Of these, polyesters such as PET, which are less transparent due to processing (heating, solvent, bending) and are highly transparent, are preferable. This polyester is a linear saturated polyester synthesized from an aromatic dibasic acid or an ester-forming derivative thereof and a diol or an ester-forming derivative thereof.

  The impression cylinder 20 has a substantially cylindrical shape and is a rotating body that can rotate around an axis. Usually, a metal such as an aluminum alloy is used. As shown in FIG. 1, the impression cylinder 20 is brought into contact with the printing substrate 18 stretched opposite to the blanket 16 from the opposite side of the transfer surface, and the transfer surface is left as it is. 16 so as to be brought into pressure contact with 16. Then, the substrate 18 to be printed sandwiched between the blanket 16 and the impression cylinder 20 moves in the direction of the arrow 200 by the rotation of the blanket 16 and the impression cylinder 20.

  Next, the positional relationship among the blanket 16, the feed roller 26-1, the plate cylinder 12 that is an intaglio, and the printing substrate 18, which is a characteristic configuration in the present embodiment, will be described.

  As shown in FIG. 1, since the blanket 16 is stretched between the feed roller 26-1 and the second roller 26-2, the blanket 16 is inscribed over the half circumference of the peripheral surface of the feed roller 26-1. (Hereinafter, this inscribed range is referred to as an inscribed range R). In the inscribed range R, the plate cylinder 12 is in contact with the blanket 16 at the peripheral surface to be an intaglio. This contact position is set as a receiving position A where the blanket 16 receives the ink 14 from the intaglio. The contact position at which the substrate 18 to be printed contacts with the blanket 16 is a position that circulates on the blanket 16 from the receiving position A in the direction of the arrow 300 within the inscribed range R. It is set as a transfer position T at which the received ink 14 is transferred to the substrate 18 to be printed. That is, in the inscribed range R, the transfer position T is provided behind the receiving position A with respect to the rotation direction of the blanket 16.

  By setting the receiving position A and the transfer position T within the inscribed range R, first, the ink 14 received by the blanket 16 is printed before the physical properties change due to long-time holding on the blanket 16. Since the ink is quickly transferred to the base material 18, the ink 14 can be satisfactorily transferred under the intended design conditions. For example, there is no possibility that the ink 14 is dried due to long-time holding on the blanket 16, the adhesiveness to the substrate 18 to be printed is changed, and problems such as deterioration in print quality are not caused.

  Second, when the receiving position A and the transfer position T are set within the inscribed range R, the plate cylinder 12 is pressed against the blanket 16 that is in circumferential contact with the feed roller 26-1, and similarly, the substrate 18 to be printed is The ink 14 is pressed against the blanket 16 that is in circumferential contact with the feed roller 26-1, and the ink 14 is appropriately received and transferred.

  Further, according to the above setting, the solvent of the ink 14 absorbed by the blanket 16 after the ink 14 is received and transferred, the blanket 16 reciprocates the distance between the feed roller 26-1 and the second roller 26-2 in the direction of the arrow 300. Then, it volatilizes while circling. Therefore, the wettability of the blanket 16 with respect to the ink 14 at the receiving position A is always maintained in the state at the start of printing, so that there is no possibility that the print quality will deteriorate even when continuous printing is performed.

  In the present embodiment, in a triangle formed by connecting the axial center of the feeding roller 26-1, the receiving position A, and the transfer position T, the inner angle i at the axial center of the feeding roller 26-1 is 90 °. Thus, the receiving position A and the transfer position T are set. This angle ranges from a minimum angle at which the plate cylinder 12 and the printing substrate 18 do not contact to a maximum of 180 ° (because the maximum range of the inscribed range R is a range where the internal angle i is 180 °). Can take. At that time, the internal angle i is preferably in the range of 45 to 170 °. When the inner angle i is smaller than 45 °, the roll radius of the impression cylinder 20 becomes half or less than the roll radius of the plate cylinder 12, so that the substrate to be printed is extremely warped and the print quality is deteriorated. It is not preferable. Moreover, when the inner angle i is larger than 170 °, the conveyance of the endless belt-like blanket 16 is not stable, which is not preferable.

  Next, printing of the printing pattern formed on the intaglio on the printing substrate 18 using the offset printing apparatus 10 according to the present embodiment will be described with reference to FIGS. 1 and 2. First, as shown in FIG. 1, the plate cylinder 12 rotates in the direction of the arrow 400 in conjunction with the rotation of the blanket 16, and the ink 14 is filled in the recess 12a. At this time, as described above, the doctor blade 24 fills the concave portion 12a with a necessary and sufficient amount of ink 14. Then, the blanket 16 and the plate cylinder 12 further circulate, and the blanket 16 receives the ink 14 filled in the concave portion 12a at the receiving position A as shown in FIG. Then, the blanket 16 further circulates in the direction of the arrow 300, and the ink 14 received by the blanket 16 contacts the printing substrate 18 at the transfer position T. As shown in FIG. 2B, the ink 14 on the blanket 16 is transferred to the printing substrate 18 at the transfer position T. The substrate 18 to which the ink 14 is transferred is conveyed in the direction of the arrow 200 by the rotation of the blanket 16 and the impression cylinder 20.

  On the other hand, the solvent contained in the ink 14 remains on the blanket 16 where the ink 14 has been received. The blanket 16 slightly swells due to the residual solvent 14a, and wettability with respect to the ink 14. Has changed. Therefore, when the portion of the blanket 16 having the residual solvent 14a reaches the receiving position A, the print quality may be affected when the ink 14 is transferred to the substrate 18 to be printed. However, as shown in FIG. 2B, the blanket 16 takes a certain amount of time until the portion having the residual solvent 14a in the blanket 16 receives the ink 14 from the plate cylinder 12 again at the receiving position A. -1 orbiting the range D (hereinafter referred to as the separation range D), the residual solvent 14a is already volatilized and removed when the ink 14 is received again, and the wettability of the blanket 16 is in the state at the start of printing. I'm back.

  Therefore, since the blanket 16 receives the ink 14 again without changing the wettability with respect to the ink 14 at the start of printing, and transfers the received ink 14 to the substrate 18 to be printed again. Even when the printing is performed, the quality of the printed pattern does not deteriorate.

  Further, the blanket 16 may be provided with a volatilization removal promoting means for promoting the volatilization removal of the residual solvent 14a. FIG. 3 is a schematic side view of the offset printing apparatus provided with the devolatilization promoting means. As shown in the figure, volatilization is performed so as to cover a substantially central portion between the feed roller 26-1 and the second roller 26-2 in the blanket 16 that passes through the transfer position T and circulates in a direction away from the feed roller 26-1. A removal promoting means 28 is provided. In the present embodiment, the devolatilization promoting means 28 is a circulation type dryer having a pipe line arranged so as to cover the blanket 16 at the above position. Warm air dried by an air dryer (not shown) circulates in the pipe line in the direction of the arrow 500, and promotes volatilization and removal of the residual solvent 14 a from the blanket 16.

  Therefore, for example, even if the length of the separation range D is insufficient to completely volatilize and remove the remaining solvent 14a due to the configuration of the apparatus, the volatilization removal promoting means 28 is provided. By promoting the volatilization removal of the residual solvent 14a, the wettability of the blanket 16 with respect to the ink 14 at the receiving position A can be maintained in the same state as at the start of printing. Further, by promoting the volatilization removal of the residual solvent 14a by the volatilization removal promoting means 28, the circulation speed of the blanket 16 can be increased and the printing speed can be improved.

  In addition, since the blanket 16 has an endless belt-like configuration stretched between the feed roller 26-1 and the second roller 26-2, the dryer using hot air is the inscribed range R as described above. It can be provided at a separated position. Therefore, there is no possibility that the heat from the dryer is transmitted to the receiving position A and the transfer position T located in the inscribed range R, and there is no influence on the transfer of the ink 14 to the printing substrate 18.

  Further, the blanket 16 is exemplified as a configuration stretched between the feed roller 26-1 and the second roller 26-2, but is not limited thereto, and a configuration supported by more rollers 26 is provided. It is also possible to apply. Hereinafter, the modification is demonstrated based on FIG. In the figure, elements similar to those in the embodiment shown in FIGS. 1 to 3 described above are denoted by the same reference numerals and description thereof is omitted.

  FIG. 4 is a view showing another aspect of the blanket 16. As shown in the drawing, the blanket 16 according to the modification includes an inner periphery of the blanket 16 between the feed roller 26-1 and the second roller 26-2 in addition to the feed roller 26-1 and the second roller 26-2. A third roller 26-3 that is in contact with the surface, and a fourth roller 26-4 that is in contact with the outer peripheral surface of the blanket 16 are disposed between the feed roller 26-1 and the second roller 26-2. The blanket 16 can be bent and arranged by this roller. Therefore, for example, the installation position of the volatilization removing unit 28 in the offset printing apparatus 10 can be optimized. Further, by arranging the blanket 16 to be bent, while ensuring the length of the blanket 16 sufficient to volatilize and remove the residual solvent 14a in the blanket 16 before receiving the ink 14 from the plate cylinder 12 again, The entire offset printing apparatus 10 can be made compact.

(Second Embodiment)
A second embodiment of the present invention will be described with reference to FIG. This embodiment is different from the first embodiment in the shape of the substrate 18 to be printed and the point that the impression cylinder 20 is not provided, and the other configurations are the same. Therefore, the different points will be mainly described. FIG. 5 is a schematic side view of the offset printing apparatus 10 according to the second embodiment of the present invention. As shown in the figure, in the present embodiment, the substrate 18 to be printed is formed as a substantially rectangular plate-like body, and the back surface is adsorbed and fixed to the conveying means 30 such as a belt conveyor by air or the like, and the direction of the arrow 600 It is conveyed to. The conveying means 30 is adjusted and arranged at a position where the transfer surface of the printing substrate 18 contacts the blanket 16 at the transfer position T in conjunction with the rotation of the blanket 16.

  According to the present embodiment, it is possible to provide a printing apparatus that can perform offset printing on a printing substrate 18 formed as a plate-like body with low flexibility, and the printing quality does not deteriorate even by continuous printing. .

  In addition, this invention is not limited to the said embodiment, A various change is possible in the range which does not deviate from the meaning of invention.

  In the above embodiment, the configuration in which the intaglio is a substantially cylindrical plate cylinder 12 is illustrated, but the configuration is not limited to this configuration as long as the blanket 16 has a configuration capable of receiving the ink 14 at the receiving position A. Absent. For example, the intaglio may have a plate-like or belt-like plate. According to these configurations, for example, a print pattern having a length exceeding the circumferential length of the plate cylinder 12 can be formed, and the print pattern can be printed on the substrate 18.

DESCRIPTION OF SYMBOLS 10 Offset printing apparatus 12 Plate cylinder 12a Recessed part 14 Ink 14a Residual solvent 16 Blanket 18 Printed substrate 20 Pressure cylinder 22 Ink storage tank 24 Doctor blade 26-1 Feed roller 26-2-4 Second to fourth roller 28 Volatilization Removal accelerating means 30 Conveying means A Accepting position D Separation range R Inscribed range T Transfer site i Inner angle

Claims (4)

An intaglio in which a printing pattern is formed, and a blanket for receiving ink filled in the intaglio,
An offset printing apparatus that prints the print pattern by transferring ink received by the blanket to a substrate to be printed,
The blanket is an endless belt stretched between a plurality of rollers including a rotating feed roller, and is configured to circulate in conjunction with the rotation of the feed roller,
The receiving position for receiving the ink of the blanket from the intaglio and the transfer position for transferring the received ink to the substrate to be printed are set within a range where the blanket is inscribed in the feeding roller,
In the inscribed range, the transfer position is provided behind the receiving position with respect to the rotation direction of the blanket. The substrate to be printed is a long thin film,
The intaglio is a substantially cylindrical plate cylinder,
A substantially cylindrical impression cylinder that presses the transfer surface of the substrate to be printed against the blanket at the transfer position;
The offset printing apparatus according to claim 1, wherein the plate cylinder, the blanket, and the impression cylinder circulate in conjunction with each other.   The inner angle at the shaft center of the feed roller is 45 to 170 degrees in a triangle formed by connecting the receiving position, the shaft center of the feed roller, and the transfer position. Offset printing device.   The volatilization removal accelerating means for promoting the volatilization removal of the solvent component in the ink absorbed by the blanket is provided outside the range where the blanket is inscribed in the feed roller. The offset printing apparatus as described.

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