JP2005144996A - Offset printing method/device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an offset printing method which can secure a successful pattern shape and a successful printing precision even for a large work size. <P>SOLUTION: In a suspended offset printing process for supporting both ends of a sheet-like or a belt-like blanket material at the forward/backward ends of a printing direction, a movement error consisting of a movement difference of a blanket 21 generated by a feed control using a drive device 36 during receiving an ink and the draw level of the blanket 21, is calculated using an arithmetic processing device 51. Further, the calculated movement error is incorporated as a correction value into a relationship at the arithmetic processing device 51 and the blanket movement is controlled by controlling the drive device 36 during transferring the ink. Thus a high-precision printing process is performed. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a printing technique suitable for forming a high-definition pattern on a component of an image forming apparatus or a printed board, and more particularly, an offset printing method suitable for printing on a flat work such as a large area glass or an epoxy board. And an offset printing apparatus.

  2. Description of the Related Art In recent years, thin flat image forming apparatuses have attracted attention as image forming apparatuses that replace large and heavy CRTs. As such a flat image forming apparatus, a TFT, a plasma display (surface conduction electron-emitting device) or the like is specifically used. A screen printing method is generally used to form a pattern on a flat work such as a glass plate or an epoxy plate for use in the electronic industry used in such an image forming apparatus. In recent years, higher resolution has been required for high-definition patterns on color filter substrates and circuit boards of image forming apparatuses, and the screen of flat-type image forming apparatuses has become larger. On the other hand, it has been required to have a large area and a high definition pattern. In order to meet the demand for such a pattern, a large offset printing apparatus having a large work size and capable of dealing with a high-definition pattern has been demanded.

  In the conventional offset printing method, a blanket is wound around a drum, the drum is rotated, and ink is received and transferred, so the drum diameter increases as the area increases, and the surface of the workpiece or plate increases as the drum diameter increases. Since the entry angle and the separation angle of the blanket are small, the control becomes difficult, and the printability such as the printing accuracy and the printing shape is deteriorated.

In order to solve such problems, there has been proposed a suspended offset printing method which is performed by supporting and suspending both ends of a blanket without winding it on a drum. In this suspended offset printing, a proposal has been made to perform printing while keeping the entry angle and separation angle between the blanket and the original plate or the workpiece constant (see Patent Document 1). Also disclosed is an invention that changes the shape of a print pattern by applying tension to the blanket during printing in the drum-type offset printing method to expand and contract the blanket (see Patent Document 2).
JP 2001-219639 A (Claim 1, FIG. 1) JP-A-6-000945

  However, in the offset printing method performed by supporting and suspending both ends of the blanket as described above, the blanket receives a force in the traveling direction by the pressing roller during printing, and the blanket moves and stretches. The amount of movement and the amount of stretching depend on various printing conditions, such as the angle of entry of the blanket with respect to the pressure roller, the angle of separation, the feed speed and pressure of the pressure roller, the blanket and the work or ink-filled printing original plate. It varies depending on the surface physical properties (rolling friction). Furthermore, even when the acceptance or transfer operation is repeated under the same conditions, changes in the surface properties such as swelling of the blanket due to the solvent in the ink and unevenness of the ink remaining on the surface of the printing original plate filled with ink, the rigidity of the printing device, etc. Since the blanket movement amount and the stretching amount differ depending on the assembling accuracy and the like, there is a problem that the work is displaced from the original plate and varies as a result, and the printing position accuracy is inferior.

  Patent Document 1 discloses a method for moving the blanket support means in the printing direction and a method for moving the platen on which the original or the workpiece is placed in the printing direction in order to correct such a deviation or variation of the workpiece from the original plate. However, it is necessary to precisely move a heavy object, and the structure is complicated.

  In order to solve these problems of the prior art, the present invention controls the above-described various printing conditions by controlling the blanket movement amount to an arbitrary value by the driving means installed on the support portion supporting the blanket. Another object of the present invention is to provide an offset printing method and an offset printing apparatus capable of controlling an error due to a blanket movement amount and a stretching amount due to a problem in the apparatus and an amount of stretching, thereby enabling high-precision printing.

The offset printing method of the present invention includes:
A printing surface plate, a blanket, a blanket support means having a support roller, and a driving device, a pressure means, a blanket position detection means, and an arithmetic processing control means for controlling the operation of the support means and the pressure means. This is an offset printing method that uses a suspended offset printing apparatus to receive ink from a printing original on a blanket and transfer ink from the blanket to a workpiece.

Support both ends of the sheet-like or belt-like blanket at the front and rear ends in the printing direction, place the printing original on the printing surface plate, move the pressing means from the back of the blanket in the printing direction and press An offset that accepts ink on the blanket surface, places the work on the printing platen instead of the printing master, and moves the pressure ink from the back of the blanket in the printing direction to transfer the ink on the blanket to the work In the printing method,
At the time of ink reception, blanket feed-out control is performed based on the first relational expression set with respect to the relation between the contact position of the pressing means with the blanket and the movement amount of the blanket, and the calculated value of the movement amount obtained by the relational expression The difference between the actual measurement value measured by the blanket position detecting means and the blanket movement amount difference is used as a blanket movement amount difference to obtain the relationship between the tension value applied to the blanket, the Young's modulus of the blanket, and the length and the extension amount of the blanket. The amount of movement of the blanket between the contact position of the pressure means and the position detection means obtained from the relational expression is added as a movement amount error, and the movement amount error is incorporated into the first relational expression. Printing is performed by performing blanket feed-out control at the time of ink transfer according to the third relational expression with corrected printing accuracy.

The offset printing apparatus of the present invention is
A printing platen on which the printing original plate and workpiece can be mounted, a blanket that accepts ink from the printing original plate and transfers it to the workpiece, and can be lifted up and down to support and suspend the blanket in the vertical direction before and after the printing direction of the printing platen A blanket supporting means having a supporting roller and a tension measuring means, and a driving device for holding the blanket under tension at both ends, a pressing means for sweeping in the printing direction while pressing the blanket from the opposite surface of the surface plate, and the blanket Position detecting means, and arithmetic processing control means for controlling operations of the supporting means and the pressing means.

  The arithmetic processing control means performs blanket feed-out control based on the first relational expression set for the relation between the contact position of the pressurizing means with the blanket and the movement amount of the blanket at the time of ink reception. The difference between the calculated amount of movement and the actual measurement value measured by the blanket position detection means is the blanket movement difference, and the tension value applied to the blanket, the Young's modulus of the blanket, and the length and the amount of blanket stretch The movement amount error is calculated by adding the blanket extension amount between the contact position of the pressurizing means and the position detection means obtained from the second relational expression for obtaining the relation between the first relational expression and the first relational expression. The blanket feed-out control at the time of ink transfer is performed by the third relational expression in which the movement amount error is incorporated and the printing accuracy is corrected. To.

  Printing is performed by performing blanket feeding control that incorporates a blanket movement amount difference obtained by actual measurement and calculation and a movement amount error due to the stretching amount, so that high-precision printing is possible.

  According to the present invention, even when large-size flat-plate offset printing is performed, there is an effect that the printing position accuracy can be ensured with a good pattern shape and high accuracy without losing acceptability / transferability over the entire surface. In addition, good printing can be similarly performed in a workpiece and a pattern area larger than those in the embodiment.

  This is because the error amount between the position information of the blanket and the value detected by the position detection unit due to the pressure roller at the time of ink reception is output as a correction value by the arithmetic processing unit, and the blanket is moved by an appropriate value in real time by the blanket driving means. This is because the ink on the surface rubber of the blanket is transferred onto the work while being driven and corrected so that the printing size becomes normal.

  The offset printing method of the present invention suspends both ends of a sheet-like or strip-like blanket at the front and rear ends in the printing direction, presses the blanket with a pressure jig and presses the blanket in the printing direction while pressing it on the plate or workpiece. In order to eliminate errors due to the amount of blanket movement and stretching between ink reception and ink transfer in an offset printing method in which ink is received from a plate to a blanket and ink is transferred from a blanket to a workpiece by sweeping, a blanket drive device is used. It is characterized by controlling the movement amount of the blanket using.

  In the offset printing apparatus of the present invention, a servo motor or a pulse motor is desirable as the blanket driving device, but a high-precision control type air cylinder or the like may be used, and the driving force may be transmitted directly to the support portion of the blanket. In addition, as a control method described in the object of the present invention described above, the amount of movement of the blanket at the time of acceptance is measured, and the difference in amount of movement from the calculated value of the amount of movement and the error due to the amount of stretching are eliminated. Printing accuracy is improved by printing with an arithmetic processing unit and printing while performing feeding control with a blanket drive unit. In order to obtain the blanket movement amount and stretch amount, the calculation method (based on the tension value and the known Young's modulus of the blanket or the corresponding length) based on mechanical analysis or the value obtained by actual measurement is set as a parameter. be able to. Further, as the position detection unit of the blanket movement amount, for example, a laser position sensor, a linear gauge or the like is desirable, but the number of pulses by a pulse motor may be used. As the arithmetic processing unit, a programmable controller is preferable, the response controllability is 100 μsec or less, and the data conversion mode is preferably 16 bits or more and having a memory function. Further, as a control method, a control method is effective in which the blanket movement amount obtained at the time of ink reception is measured by the above-described position detection unit, and is adjusted with the driving force of the driving device at the time of transition so as to be the same movement amount. . In the present invention, the amount of movement of the blanket can be arbitrarily controlled at the time of ink transfer. It is an object of the present invention to provide a highly accurate offset printing method by eliminating the influence of an operation error held by a machine.

  Next, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a schematic block side view of an offset printing apparatus used in an offset printing method according to an embodiment of the present invention. In this figure, the pressing roller 41 is guided by a guide beam member 47 via a pressing jig moving part 44 of a pressing jig 40 having a printing push amount setting part 43 and can move along the printing direction. The supporting column 46 and the supporting column 45 are erected on the main body frame 11 and support both ends of the beam member 47 for the travel guide of the pressing roller 41. The printing original plate 61 is provided on the printing surface plate 12 when ink is received. However, the print work 62 is set during ink transfer.

  In the offset printing apparatus 1, first, a printing original plate 61 for transferring ink to the blanket 21 is placed on the printing surface plate 12 so that the ink is received by the blanket 21, and then the work 62 for transferring ink from the blanket 21. Is placed on the printing surface plate 12 to perform printing by transferring ink. Both ends of the blanket 21 are suspended above the printing surface plate 12 by a support portion 30 having lifting devices 33 and 34 and support rollers 31 and 32 at the upper ends thereof. In addition, the support unit 30 of the offset printing apparatus 1 is provided with drive devices 35 and 36 that hold the end of the blanket 21 and apply tension to the blanket 21 by driving a pulse motor at both ends. The driving devices 35 and 36 are provided with tension measuring devices 37 and 38 for calculating the stretch amount of the blanket 21. Further, the drive device 35 at one end is internally provided with a position detection unit 39 for measuring the movement amount of the blanket 21. Further, the offset printing apparatus 1 has a support structure in which upper end support rollers 31 and 32 constituting a support portion 30 that supports both ends of the blanket 21 are vertically movable by elevating devices 33 and 34, and the upper end support. It is possible to change the entry angle α and the separation angle β by raising and lowering the rollers 31 and 32. Further, the lifting devices 33 and 34 constituting the blanket support portion 30 that supports both ends of the blanket 21 and the support rollers 31 and 32 at the upper end thereof have a support structure movable in the printing direction, and the support portion 30 moves. It is good also as a structure which can change the approach angle (alpha) and the leaving angle (beta) by. The movement amount and the stretching amount error generated during printing are corrected by driving a pulse motor for driving a blanket. An arithmetic processing unit 51 is installed as a control means in the vicinity of the printing apparatus main body. As the arithmetic processing unit 51, a programmable controller having a response control speed of 5 μsec is used.

  The arithmetic processing unit 51 is connected to a recording device 52 that acquires and records the position detection data detected by the position detection unit 39, receives the position detection data sent thereto, and determines from the blanket movement amount and the stretching amount. In order to eliminate the difference between the blanket movement amount and the stretching amount generated at the time of ink reception and ink transfer, the movement of both ends of the suspended blanket 21 is moved along with printing. The amount can be controlled arbitrarily. The offset printing apparatus 1 performs printing by the pressing roller 41 being moved and swept on the blanket 21 by being guided by the guide beam member 47 from the left end to the right end of the printing original plate 61 or the workpiece 62 in the drawing. Is called. FIG. 2 is a graph showing the relationship between the calculation response control speed (μsec) on the horizontal axis and the variation accuracy (μm) with respect to the original plate dimension length on the vertical axis. This graph shows that when the response control speed is 10 μsec or less, there is little variation and printing can be performed with high accuracy.

  Moreover, the blanket 21 consists of a base fabric material and silicone rubber, and FIG. 3 is a graph which shows an example of the relationship between the elapsed time of a blanket, and the amount of extending | stretching. A rubber material such as silicone or NBR is formed on the ink placement surface (lower surface), and is developed so as to be swept in the printing direction above the horizontal printing platen 12. It is supported and suspended at both ends of the printing surface plate 12 by support rollers 31 and 32 as support means that can control the vertical movement by an air cylinder or the like, and details will be described later on the terminal of the blanket 21. A tension applying means is connected.

  The tension applying means includes drive devices 35 and 36 each having a take-up roll, and the end of the blanket 21 is wound around and fixed to the take-up roll. In addition, tension measuring devices 37 and 38, which are connected to the shaft of the take-up roll and are composed of sensors for calculating the stretch amount of the blanket, are provided. For this sensor, a load cell or a linear gauge is preferably used, but when a servo motor or a pulse motor is used to drive the driving devices 35 and 36, a counter for measuring the number of pulses may be used.

  In particular, in the apparatus of the present invention, the tension applying means applies a tensile force toward the printing direction to the blanket 21 at a constant tension value at all times during the printing operation. For this reason, the present invention includes an arithmetic processing unit 51 which is a control means for controlling the stretch amount value based on the tension value based on the measurement values from the tension measuring devices (sensors) 37 and 38. In this embodiment, there is a recording device 52 that records a measurement value that is a basis for calculating an error.

  The ink placement surface of the blanket 21 is brought into contact with the printing original plate 61 or the work 62, and the printing is accepted (the ink image of the printing original plate 61 is received by the blanket 21) or the printing transfer (the ink image carried on the blanket 21 is received). In the offset printing apparatus 1 of the present invention, a pressing jig 40 is prepared for transferring to the surface of the workpiece 62. The pressurizing jig 40 includes a printing push amount setting unit 43, a pressurizing jig moving unit 44, an elevating device (not shown) such as an air cylinder, and a blanket width provided at the lower end of the elevating member. A pressing roller 41 having substantially the same length is provided. Then, the pressing roller 41 is pushed down to sweep the blanket 21 in the printing direction with respect to the printing original plate 61 carrying the ink image. In addition, before and after the printing direction, portal-shaped columns 45 and 46 are provided, and a beam member 47 for a traveling guide is installed on this, and a pressurizing jig 40 is added along this. The pressure jig moving unit 44 can reciprocate. The movement control of the pressurizing jig 40 can be performed by driving an actuator (not shown) by a control signal of the arithmetic processing unit which is the above-mentioned control means, but other means may be used. .

  In this embodiment, the blanket 21 serves as the printing original plate 61 or the work 62 in relation to the movement of the pressing portion of the pressing jig 40 with respect to the blanket 21 before and after the pressing jig 40 in the sweep process. It is necessary to provide means for controlling the entry angle α and the withdrawal angle β.

  In particular, the means for controlling the approach angle α and the separation angle β described above gives control commands to the lifting devices 33 and 34, and the lifting devices 33 and 34 that have received the control command are at least before and after the print effective area of the blanket 21. The support rollers 31 and 32 as support means for supporting the height of the blanket so as to be adjustable are moved up and down. Further, the entry angle α and the separation angle β are always maintained at arbitrary set angles (particularly preferably, the entry angle α = the separation angle β) during the printing operation.

  In such a configuration, during printing, the pressing roller 41 attached to the tip of the pressing jig 40 is lowered while pressing the back surface of the blanket 21, and the blanket surface (ink placement surface) is the printing original plate 61 or the work 62. The crimping is performed with the set push amount. At this time, a constant tension is applied to the blanket 21 by the driving devices 35 and 36 at both ends. Thereafter, when the pressing roller 41 moves (sweeps) from the left end to the right end of the printing original plate 61 or the work 62, printing acceptance or printing transfer is performed.

  At this time, before and after the pressing roller 41, the lifting and lowering devices 33 and 34 automatically control the heights of the support rollers 31 and 32, respectively, with respect to the entry angle α and the separation angle β that the blanket 21 makes with the printing original plate 61 or the work 62. Thus, it is maintained at an arbitrary set angle during the printing operation.

  This makes it possible to significantly reduce the initial elongation of the blanket material, which is particularly large immediately after application. Furthermore, even when the optimum tension values are different at the time of printing acceptance and printing transition, printing can be performed while continuously changing the tension without reducing the blanket tension.

  In this case, at the time of printing acceptance / transfer, the tension higher than the set tension value is continuously applied to the blanket 21 until the pressing roller 41 is operated in the effective printing area (effective pattern range), and immediately before the effective printing area. By returning to the set tension value, the stretch amount due to the elongation over time inherent in the blanket material can be reduced in the effective printing region, and printing can be performed with higher accuracy.

  Up to now, the characteristic offset printing method has been described focusing on the configuration of the offset printing machine to which the offset printing method of the present invention is applied. However, the offset printing method of the embodiment of the present invention will be described with reference to flowcharts. To do. FIG. 4 is a flowchart of the offset printing method according to the embodiment of the present invention.

  When printing is started (S11), the printing original plate 61 is placed on the printing surface plate 12 (S12). The pressing roller 41 is moved down at the start position (S13), and a predetermined pressing amount is set by the printing pressing amount setting unit 43 (S14). The heights of the front and rear support rollers 31 and 32 are adjusted by the elevating devices 33 and 34 so that the entry angle α and the separation angle β become predetermined angles (S15), and the pressing roller 41 is moved by the pressing jig moving unit 44. The vehicle is moved forward at a predetermined speed (S16), the blanket position is measured by the position detector 39 (S17), and the drive of the blanket 21 is controlled by the driving devices 35 and 36 based on a predetermined relational expression (S18). The heights of the front and rear support rollers 31 and 32 are adjusted by the elevating devices 33 and 34 so that the entry angle α and the separation angle β become predetermined angles corresponding to the forward movement of the pressing roller 41 (S19, 20). The roller 41 is advanced to the final position (S21N). When the pressing roller 41 reaches the final position (S21Y), the pressing roller 41 is raised and returned to the start position (S22), and the receiving process is terminated.

  Next, the printing original plate 61 is replaced with the workpiece 62 (S23), and the transfer process similar to that in steps S13 to S22 of the receiving process is repeated in steps S24 to S33. However, in step S29, measurement and calculation is performed at the time of receiving unlike step S18. Extrusion control is performed by the driving devices 35 and 36 based on the relational expression corrected based on the movement error, and this step S29 is a feature of the present invention. When the pressure roller 41 reaches the final position (S32Y), the pressure roller 41 is raised and returned to the start position (S33). If the work 62 is removed to complete the transfer process and continue printing (S35N), Returning to step S12, printing is repeated.

  Of course, in the offset printing apparatus 1 of the present invention, in the printing work process, if the printing process is interrupted and an exchange process for exchanging the original plate or the workpiece with another type is interposed as shown in FIG. Good.

Next, an example of offset printing using the above-described printing apparatus will be described.
(Example 1)
Using the suspended offset printing apparatus of FIG. 1, actual printing was performed in the following manner.
・ Blanket 21 used:
Surface silicone rubber blanket (width: 400 mm x length: 1800 mm web, thickness: 2 mm,
Elongation rate: 1.5%, 1000 kg / 1 m width load)
・ Used printing master 61:
Intaglio plate made of glass (Outline = width: 350 mm x length: 300 mm x thickness: 3 mm)
(Pattern area = width: 210 mm x length: 160 mm)
-Work 62 used:
Blue plate glass (Outside = Width: 350mm x Length: 300mm x Thickness: 3mm)
・ Ink used:
Gold resinate paste (containing solvent: terpineol & BCA)
Use pressure roller 41:
Made of steel (diameter: 35mm x width: 450mm)
・ Doctor blade used:
Made of steel (Outside = Width: 450mm x Height: 20mm x Thickness: 2mm)
After preparing the above members, the ink is spread on a glass intaglio plate (printing original plate) 61, and the printing original plate 61 scraped off the excess ink with a doctor blade is placed on the printing surface plate 12, and the upper left end of the printing original plate 61 is The pressing roller 41 was pressed while pressing the back surface (ink placement surface) of the blanket 21. At this time, the pressing value of the pressing roller 41 was 100 kg.

  Next, the pressing roller 41 was moved rightward in FIG. 1 at a speed of 10 mm / second. At this time, blanket position information of the pressing roller 41 every 0.1 second was detected by a Canon linear encoder ML-20, and ink was received on the surface rubber of the blanket 21. At this time, the blanket elevating devices 33 and 34 set the initial approach angle α formed by the blanket 21 to the printing original plate 61 to 10 degrees and the separation angle β to 10 degrees. By this operation, the error amount obtained by combining the movement amount of the blanket 21 and the stretching amount at the time of acceptance was a deviation of -10.020 mm with respect to the entire pattern area of 200 mm.

  Next, the printing original plate 61 on the printing surface plate 12 was removed, and a blue plate glass work 62 was placed instead, and the pressing roller 41 was pressed against the left end of the work 62 while pressing the back surface of the blanket 21 as before. Next, the blanket movement amount and the stretching amount difference obtained by the calculation method based on the mechanical analysis are input to the arithmetic processing unit 51, and then the pressing roller 41 is moved rightward in FIG. 1 at a speed of 10 mm / second. It was. An error amount between the position information of the blanket 21 detected by the pressure roller 41 at the time of ink reception and detected by the linear encoder L-20 is output as a correction value by the arithmetic processing unit 51. The blanket 21 was driven by an appropriate value in real time by the blanket driving means, and the ink on the surface rubber of the blanket 21 was transferred onto the work 62 while correcting the printing dimensions to be normal.

  With the above procedure, the ink of the pattern shape of the printing original plate 61 moved to the work 62 via the blanket 21, and the offset printing of the present invention was completed. With this operation, the difference in blanket movement amount between ink reception and ink transfer was +4 μm with respect to the pattern area of 200 mm.

  In this embodiment, the print pattern shown in FIG. 6 was used. That is, it is a pattern of 160 μm × 80 μm rectangles arranged at intervals of 200 μm in the printing direction and at intervals of 160 μm in the width direction.

The pattern printed on the soda-lime glass workpiece 62 in the above embodiment was observed using a microscope, but a good printed pattern with no pattern omission or chipping was obtained on the entire pattern area (210 mm × 160 mm). It was. Moreover, the uniform film thickness within 10% of the film thickness difference was obtained also by the measurement result by the film thickness measuring instrument. Furthermore, regarding the printing accuracy, which is the greatest feature of the present invention, the displacement was ± 5 μm over the entire length, and the printing position accuracy was good. FIG. 7 is a graph showing the relationship between the printing speed (mm / second) and the pattern transfer rate (%) when printing is performed by the offset printing method according to the first embodiment of the present invention. This graph shows that a high pattern transfer rate can be obtained at a printing speed of 10 mm / second or less.
(Example 2)
In the offset printing according to the second embodiment of the present invention, the printing speed at the time of acceptance was increased. The basic configuration is the same as in the first embodiment. The purpose of the printing method or apparatus according to the present embodiment is to improve productivity and maintain or improve print quality by increasing printing speed. That is, at the time of ink reception, only the blanket movement amount and the stretching amount were measured, and in order not to perform the control, the printing speed was 100 mm / sec. In order to suppress the volatilization of the ink solvent set on the glass intaglio printing original plate 61, this effect is quickly transferred from the glass intaglio printing original plate 61 to the blanket 21, so that the pattern made of ink in the entire printing area is blanket 21. It is to be formed uniformly. Further, this advantage is particularly effective when a fine pattern (a pattern of several μm) that is easy to dry is formed.

  In the present embodiment, it is necessary to measure the blanket movement amount during the above-described reception printing. Based on the measurement results of the blanket movement amount and the stretching amount at the time of the accepting printing, at the time of transfer printing, the drive devices 35 and 36 have the same blanket moving amount and the stretching amount as at the time of the accepting printing as in the first embodiment. By controlling to give high-speed printing, high-precision and high-quality printing is possible. When the reproducibility by the offset printing method according to this example was repeated 30 times, the printing position accuracy was as good as ± 10 μm.

  FIG. 8 is a graph showing the relationship between the printing speed (mm / second) and the pattern transfer rate (%) when printing is performed by the offset printing method according to the second embodiment of the present invention. This graph shows that a high pattern transfer rate can be obtained even when the printing speed exceeds 100 mm / sec. In this way, it is possible to print at a much higher speed than in the second embodiment.

(Comparative Example 1)
In the first and second embodiments, it has been described that high-precision printing can be obtained by detecting the blanket position according to the present invention and controlling the blanket movement amount and the stretching amount. The comparative example to be described below is a printing accuracy result by a printing method in which the blanket movement amount and the stretching amount are not controlled, but the tension of the blanket is measured by a tension gauge and the tension value is controlled to be constant.

  The basic configuration of the blanket, glass intaglio, blue plate glass, printing ink, etc. used in this comparative example is the same as in the first embodiment, and the blanket tension is measured with a tension gauge so that the tension value becomes constant. When printing was performed with the printing method controlled in the above, the blanket movement amount at the time of acceptance printing was ± 10.18 mm, and the blanket movement amount at the time of transfer printing was −9.960 mm. As a result, the positional accuracy in the print pattern increased to +58 μm. Further, in order to confirm reproducibility, the process was repeated 30 times, and the positional accuracy variation was ± 80 μm over the entire printing area, which was a worse result than that of the first embodiment of the present invention.

It is a typical block side view of the offset printing apparatus used for the offset printing method of an embodiment of the invention. It is the graph which showed the relationship between the calculation response control speed (microsecond) taken on the horizontal axis, and the variation precision (micrometer) with respect to the original plate dimension length taken on the vertical axis. It is a graph which shows one example of the relationship between the elapsed time of a blanket, and the amount of extending | stretching. It is a flowchart of the offset printing method of an embodiment of the invention. It is a schematic diagram which shows the replacement | exchange process which interrupts printing and changes an original plate and a workpiece | work to another kind in a printing work process. It is a schematic diagram of the printing pattern at the time of printing by the offset printing method concerning the 1st Example of this invention. It is a graph which shows the relationship between printing speed (mm / sec) and pattern transfer rate (%) at the time of performing printing by the offset printing method concerning the 1st example of the present invention. It is a graph which shows the relationship between printing speed (mm / sec) and pattern transfer rate (%) at the time of performing printing by the offset printing method concerning the 2nd example of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Offset printing apparatus 11 Main body frame 12 Printing surface plate 21 Blanket 30 Blanket support part 31, 32 Support roller 33, 34 Lifting apparatus 35, 36 Driving device 37, 38 Tension measuring device 39 Position detection part 40 Pressure jig 41 Pressing roller 43 printing push amount setting unit 44 pressure jig moving unit 45, 46 column 47 beam member 51 arithmetic processing unit 52 recording device 61 printing original plate 62 work S11 to S36 steps

Claims (2)

A printing platen on which a printing original plate and a workpiece can be mounted, a blanket that receives ink from the printing original plate and transfers it to the workpiece, and a suspension that supports the blanket in the vertical direction before and after the printing direction of the printing platen A support roller capable of moving up and down, and a blanket support means having a tension measuring means and a driving device for applying tension to the blanket at both ends, and sweeping in the printing direction while pressing the blanket from the opposite surface of the surface plate A suspended offset printing apparatus comprising: a pressurizing unit that detects a position of the blanket; and a calculation processing control unit that controls the operation of the support unit and the pressurizing unit. Alternatively, both ends of the belt-like blanket are supported at the front and rear ends in the printing direction, the printing original plate is placed on the printing surface plate, and the pressurizing unit The printing plate is moved in the printing direction while being pressed from the back side of the blanket, the ink of the printing original plate is received on the blanket surface, the work is placed on the printing platen instead of the printing original plate, and the pressing unit In the offset printing method of transferring the ink of the blanket to the work by moving in the printing direction while pressing from the back of the blanket,
At the time of ink reception, blanket feeding control is performed based on the first relational expression set for the relation between the contact position of the pressurizing unit with the blanket and the movement amount of the blanket, and the movement amount obtained by the relational expression The difference between the calculated value of the blanket and the actual measurement value measured by the position detecting means of the blanket is defined as a blanket movement amount difference, the tension value applied to the blanket, the Young's modulus of the blanket, and the length and the amount of the blanket stretched The amount of extension of the blanket between the contact position of the pressurizing unit obtained from the second relational expression to obtain the relationship with the blanket and the position detecting unit is added to obtain a movement amount error, and the first unit Blanket feeding control at the time of ink transfer by the third relational expression in which the movement amount error is incorporated into the relational expression and the printing accuracy is corrected. Offset printing method and performing printing performed. A printing platen on which a printing original plate and a workpiece can be mounted, a blanket that receives ink from the printing original plate and transfers it to the workpiece, and a suspension that supports the blanket in the vertical direction before and after the printing direction of the printing platen A support roller capable of moving up and down, and a blanket support means having a tension measuring means and a driving device for applying tension to the blanket at both ends, and sweeping in the printing direction while pressing the blanket from the opposite surface of the surface plate In a suspended offset printing apparatus comprising: a pressurizing unit, a position detecting unit that detects a position of the blanket, and an arithmetic processing control unit that controls the operation of the support unit and the pressurizing unit.
The arithmetic processing control means performs blanket feed-out control based on a first relational expression set with respect to a relation between a contact position of the pressurizing means with the blanket and a movement amount of the blanket at the time of ink reception. The difference between the calculated value of the movement amount obtained by the equation and the actual measurement value measured by the position detecting means of the blanket is defined as a blanket movement amount difference, the tension value applied to the blanket, the Young's modulus of the blanket, and Move by adding the amount of extension of the blanket between the contact position of the pressure means and the position detection means obtained from the second relational expression for obtaining the relationship between the length and the amount of extension of the blanket Ink transfer is calculated by a third relational expression that calculates the amount error and corrects the printing accuracy by incorporating the movement amount error into the first relational expression. Offset printing apparatus characterized by performing a blanket feeding control.

Images