JP2010274461A - Printing system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a printing system capable of printing an image excellent in outward appearance without using a highly white newsprint paper and capable of easily creating the newspaper high in added value. <P>SOLUTION: The printing system 1 for printing an image on a travelling paper P which travels in a prescribed direction comprises: a plurality of printing cylinders 2 which are arranged along a travelling path of the travelling paper P and perform offset printing of the image while being rotated; and an inkjet printer 3 which is arranged on the upstream side of the plurality of printing cylinders 2 when viewing from the passage of the travelling paper P and sprays ink to the travelling paper P to print the image, whereby the substrate treatment is performed on the travelling paper P by the printing by means of the inkjet printer 3 and, at the same time, offset printing by means of the printing cylinders 2 is performed on an area where the substrate treatment on the travelling paper P is performed. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a printing system that prints an image on traveling paper that travels in a predetermined direction, and more particularly to a printing system that prints a paper surface on newsprint.

  2. Description of the Related Art Conventionally, it has been widely performed that advertising information is posted on a newspaper and a newspaper is used as an advertising medium. In this case, the advertiser who requests the advertisement placement in the newspaper desires the publication in a state that is colorful and looks good and is conspicuous as a whole so as to draw the attention of the newspaper reader to his advertisement.

  In addition, on the article posting side of newspapers, color photographs taken on the spot may be posted, but in order to accurately convey the situation on the spot to the reader, it is desirable to post a clear image.

  However, ordinary newsprint paper has a lower whiteness than art paper and coated paper, so that the image quality of the printed surface is inferior and it is difficult to print a colorful color image. For this reason, some newspaper companies use high-white newsprint with high whiteness to meet the demands of advertisers and readers (see, for example, Patent Documents 1 and 2).

JP 2002-69896 A JP 2008-196090 A

  However, since high-white newsprint is more expensive than normal newsprint, there is a problem in that it increases the manufacturing cost of newspapers and increases the burden on newspaper publishers and raises the advertising fees. In addition, it is possible to minimize the increase in paper cost by making a newspaper using a combination of high-white newsprint paper and ordinary newsprint paper. In this case, however, the web of the rotary press is used in the newspaper printing process. It becomes necessary to replace the work, and a reduction in work efficiency is unavoidable.

  Further, high white newsprint is not usable only for a part of one page, and is limited to use in units of paper, so it is not necessarily easy to use for a newspaper company. That is, even when only one of the newspapers is a high white newsprint, it is necessary to secure an advertisement request for filling the paper area for two pages (the front and back surfaces of one sheet). There is a problem that the burden of the increase.

  Therefore, the present invention has been made in view of the problems in the above-described conventional technology, and can print an excellent-looking image without using high-white newsprint paper. An object of the present invention is to provide a printing system that can be easily created.

  In order to achieve the above object, the present invention is a printing system for printing an image on a traveling paper traveling in a predetermined direction, and is arranged along the traveling path of the traveling paper and printing a plurality of images while rotating. And an inkjet printing machine that is disposed on the upstream side of the plurality of printing cylinders as viewed from the flow of the traveling paper and that prints an image by spraying ink onto the traveling paper.

  In the above printing system, it is possible to perform the background processing on the traveling paper by printing with the ink jet printer, and to perform printing on the traveling paper on the traveling paper on the traveling cylinder.

  The printing system may further include a control unit that controls printing timing of the ink jet printing machine based on an encoder signal indicating a rotation amount and a rotation speed of the printing cylinder.

  In the printing system, a starting point of an inkjet printing area to be printed on the running paper is designated by the number of pulses of the encoder signal, the control unit counts the number of pulses of the encoder signal, and the count value is the start value. When the number of pulses designated as a point coincides, printing of the ink jet printer can be started.

  In the printing system, an end point of the ink jet printing region is designated by the number of pulses of the encoder signal, and the ink jet printing is performed when the control unit matches the number of pulses designated as the end point. The printing of the machine can be stopped.

  The printing system may include a second ink jet printer that is disposed on the downstream side of the plurality of printing cylinders when viewed from the flow of the traveling paper and that sprays glossy ink on the traveling paper.

  As described above, according to the present invention, it is possible to print an excellent-looking image without using high white newsprint, and it is possible to easily create a high-value-added newspaper.

BRIEF DESCRIPTION OF THE DRAWINGS It is a block diagram which shows one Embodiment of the printing system concerning this invention, Comprising: (a) is a general view, (b) is an expansion perspective view of A part of (a). It is a figure which shows an origin signal and an encoder signal. It is a figure which shows the installation position of a 1st inkjet printing machine. It is a figure for demonstrating operation | movement of the printing system of FIG. It is a schematic diagram of the printing data for inkjet. It is a figure which shows the structure of a 1st inkjet printing machine. It is a figure which shows the structure of the recording head of a 1st inkjet printing machine. It is a figure which shows the structure of a 1st control part. FIG. 9 is a configuration diagram illustrating a sub-scanning print area signal generation unit in FIG. 8. It is a schematic diagram of printing start data and printing end data. It is a figure for demonstrating operation | movement of the printing origin signal generation circuit of FIG. FIG. 10 is a timing diagram for explaining the operation of the sub-scanning print area signal generation unit of FIG. 9. It is a block diagram which shows the main scanning printing area signal generation part of FIG. FIG. 14 is a timing chart for explaining the operation of the main scanning print area signal generation unit of FIG. 13. It is a block diagram which shows the recording head control part of FIG. FIG. 16 is a timing chart for explaining the operation of the thinning circuit in FIG. 15. FIG. 16 is a timing chart for explaining the operation of the delay circuit of FIG. 15. It is a timing diagram for demonstrating operation | movement of a 1st inkjet printing machine. It is a block diagram which shows a 2nd inkjet printing machine. It is a block diagram which shows the recording head of a 2nd inkjet printing machine. It is a timing diagram for demonstrating operation | movement of a 2nd inkjet printing machine. It is a schematic diagram for demonstrating operation | movement of a 2nd inkjet printing machine. FIG. 10 is a timing diagram for explaining another example of generation of a printing origin signal.

  Next, modes for carrying out the invention will be described in detail with reference to the drawings. In the following, a case where the printing system according to the present invention is applied to a tower type offset rotary press will be described as an example.

  FIG. 1 shows an embodiment of a printing system according to the present invention. This printing system 1 is roughly divided into a plurality of printing cylinders 2 (2c) arranged along a traveling path of traveling paper (newspaper paper) P. ~ 2k), a first ink jet printer 3 arranged below the printing cylinder 2, a first control unit 4 for controlling the printing operation of the first ink jet printing machine 3, and arranged above the printing cylinder 2 A second inkjet printer 5, a second control unit 6 that controls the printing operation of the second inkjet printer 5, and a paper feed unit 7 that supplies the running paper P are provided.

  In FIG. 1, the first control unit 4 is illustrated separately from the first inkjet printing machine 3, but the first control unit 4 may be provided in the first inkjet printing machine 3. This is the same between the second inkjet printer 5 and the second controller 6.

  The plurality of printing cylinders 2 are for offset printing of characters and color images on the running paper P. For example, C (cyan), M (magenta), Y (yellow), and K (sumi) in this order from the bottom. Is arranged for each color. As shown in FIG. 1B, each printing cylinder 2 is transferred from the printing cylinder 12 on which the printing plate 11 is mounted, an ink supply mechanism (not shown) for supplying ink to the printing cylinder 12, and the printing cylinder 12. And a blanket cylinder 13 for printing an image on the running paper P using the ink to be printed. Two sets of the plate cylinder 12, the ink supply mechanism, and the blanket cylinder 13 are arranged corresponding to the front and back surfaces of the running paper P.

  The plate cylinder 12 is provided with a positioning sensor 15 for performing reference position alignment (origin detection) of the plate cylinder 12 (press plate 11). From the positioning sensor 15, an origin signal OS (see FIG. 2) that rises to an H level is output every time the plate cylinder 12 makes one rotation. This origin signal OS is the origin of printing of one sheet area on the running paper P (see FIG. 2). 3) shows the timing when the printing cylinder 2 passes through the printing position (the contact point between the blanket cylinder 13 and the running paper P).

  The blanket cylinder 13 is provided with an encoder (speed phase detector) 14 that detects the rotation angle and rotation speed of the blanket cylinder 13 and detects the feed amount and the traveling speed of the traveling paper P. From the encoder 14, an encoder signal EN (the level of which changes according to the amount of rotation of the blanket cylinder 13 (the amount of travel of the traveling paper P) and the pulse width expands and contracts according to the rotational speed (the traveling speed of the traveling paper P). 2) is output.

  The first ink jet printer 3 is provided, for example, for applying white ink to the traveling paper P and performing a background treatment on a print area of an advertisement surface or a photographic surface. The first ink jet printer 3 is arranged so as to be located upstream of the printing cylinder 2 when the flow of the running paper P is used as a reference, and a plurality of ink blowing nozzles are arranged therein.

  Further, as shown in FIG. 3, the first inkjet printing machine 3 has a printing position (ink adhesion position) of the first inkjet printing machine 3 and a printing position (blanket cylinder 13 and traveling paper) of the lowermost printing cylinder 2c. It is installed so that the distance from the contact point to P) is the reference length (1L) of one newspaper page or a multiple thereof. In the first ink jet printing machine 3, two sets are arranged corresponding to the front and back surfaces of the running paper P as in the printing cylinder 2 (see FIG. 1).

  The second ink jet printer 5 is provided, for example, for applying a UV curable clear ink to the traveling paper P and performing gloss processing and protection processing. The second inkjet printer 5 is arranged to be positioned downstream of the printing cylinder 2 when the flow of the running paper P is used as a reference, and is configured to apply clear ink to the running paper P after four-color printing. Is done.

  An ultraviolet lamp 8 that irradiates the traveling paper P with ultraviolet rays and cures the clear ink is provided at the subsequent stage of the second inkjet printer 5. In the second inkjet printer 5, as in the case of the first inkjet printer 3, the interval between the print position of the second inkjet printer 5 and the print position of the uppermost printing cylinder 2k is 1L or a multiple thereof. It is installed to become.

  Next, the operation of the printing system 1 having the above configuration will be described with reference to FIGS.

  In the printing process, first, as shown in FIG. 4A, the first ink jet printer 3 applies white ink to a partial area on the running paper P and prints the white background 17. Control of the printing timing and printing width at this time is performed based on the inkjet print data, the encoder signal EN and the origin signal OS from the lowermost printing cylinder 2c (the printing cylinder closest to the first inkjet printing machine 3) ( FIG. 1 (a)). Details of the control of the printing timing and the like will be described later.

  Here, the ink jet print data designates an ink jet print area on the running paper P, and is supplied from an image processing apparatus (not shown) such as a CTP apparatus. For example, as illustrated in FIG. 5, the inkjet print data is generated by masking a portion 21 other than the inkjet print region 18 with respect to the combined data 20 obtained by combining the one-sheet data 19.

  Next, in a plurality of printing cylinders 2, offset printing is performed on the traveling paper P to print a newspaper surface. At this time, as shown in FIG. 4B, characters and the like are offset printed in an area other than the white background 17 to create the normal printing unit 22, and predetermined advertisement information and photographic images are offset on the white background 17. A special printing unit 23 for printing is created by printing.

  Next, in the second ink jet printer 5, the clear ink is applied on the special printing unit 23 of the running paper P, and gloss processing is performed. Control of the printing timing and printing width at this time is performed based on the inkjet print data, the encoder signal EN and the origin signal OS from the uppermost printing cylinder 2k (the printing cylinder closest to the second inkjet printing machine 5) ( FIG. 1 (a)).

  Next, the ultraviolet lamp 8 irradiates the traveling paper P with ultraviolet rays to dry the clear ink. Thereafter, in a subsequent folding unit (not shown), the traveling paper P is cut into a predetermined size, and the cut traveling paper P is folded into a newspaper.

  According to the above configuration, since the white background 17 is formed on the running paper P by ink jet printing, the whiteness of the paper P can be increased in the area where the white background 17 is formed. If offset printing is performed on the white base 17 with the printing cylinder 2, it is possible to perform colorful printing, and it is possible to print advertisement information, photographs, etc. that are excellent in appearance even with ordinary newspaper paper. Become.

  Further, since the white base 17 can be formed in a partial area on the running paper P, only a necessary area on the newspaper surface can be partially colored. For this reason, the size of the white background 17 can be appropriately set according to the amount of advertisement requests, and it becomes possible to eliminate an increase in burden on the acquisition side of advertisement requests. In addition, since there is no need to switch sheets during printing, workability can be improved.

  Furthermore, since the gloss can be imparted by the second ink jet printing machine 5, it is possible to perform printing with better appearance and to create a newspaper with high added value.

  Next, details of the first ink jet printer 3 and its control unit 4 will be described with reference to FIGS. In the following, a case where the interval between the printing position of the first inkjet printing machine 3 and the printing position of the lowermost printing cylinder 2c is 1 L will be described as an example.

  As shown in FIG. 6, the first inkjet printing machine 3 includes a plurality of recording heads 31 (1) to 31 (n) (n is a natural number of 2 or more) arranged along the width direction W of the running paper P. Each recording head 31 is provided with a plurality of nozzles 32 (1ch to m (m is a natural number of 2 or more) ch) arranged in the width direction W.

  In these recording heads 31 (1) to 31 (n), adjacent recording heads 31 are arranged in steps in order to avoid a gap in the arrangement region 33 of the nozzles 32. In the following description, the upstream (lower stage) recording heads 31 (1 to n) are referred to as 31 (1 to n) h, and the downstream (upper stage) recording heads 31 (1 to n) are referred to as 31 ( 1 to n) d.

  The recording head for ink jet printing includes a continuous method and a drop-on-demand method, and the recording head 31 of the first ink jet printer 3 uses a continuous ink jet head advantageous for high-speed printing. In the continuous inkjet head, as shown in FIG. 7, the piezoelectric element 35 is vibrated at high frequency by the drive clock PC from the high frequency power supply 41, and ink droplets 36 are continuously ejected from the nozzle 32 at a constant pitch.

  When the ink droplets 36 ejected from the nozzles 32 are attached to the traveling paper P, the ink droplets 36 are caused to fly through the flight route without being charged. On the other hand, when the ink droplets 36 from the nozzles 32 are not attached to the running paper P, the ink droplets 36 are charged to change the flight path and are collected in the ink storage tank 40 via the collection wall 39 (see 36 ′). . The collected ink droplets 36 'are returned to the nozzles 32 and recycled. In the present embodiment, the first control signal IN1 generated by the first control unit 4 is used as the drive signal for the electrode 37.

  As described above, the first control unit 4 is for controlling the printing operation of the first inkjet printer 3, and as shown in FIG. 8, the sub-scanning print area signal generating unit 46, the main-scanning printing area signal, The generator 47 and the recording head controller 49 are included.

  The sub-scanning print area signal generation unit 46 is provided to generate a sub-scanning print area signal VPS that designates an ink jet printing area in the sub-scanning direction (the running direction R of the running paper P).

  As shown in FIG. 9, the sub-scanning print area signal generator 46 generates a print origin signal generation circuit 51 that generates a print origin signal POS, a counter 52 that counts an encoder signal EN, and a count value CV1 of the counter 52. The comparison circuit 53 that compares the (sub) start position data VS, the comparison circuit 54 that compares the count value CV1 with the (sub) end position data VE, and the sub-scanning print area signal VPS based on the outputs of the comparison circuits 53 and 54. And a sub-scan enable generation circuit 55 for generating.

  Here, as shown in FIG. 10, the (sub) start position data VS designates the start point in the subscanning direction of the area (inkjet printing area) where the white background 17 is to be formed. Defined by EN pulse number. On the other hand, the (sub) end position data VE designates the end point of the white background 17 in the subscanning direction, and is defined by, for example, the number of pulses of the encoder signal EN, like the (sub) start position data VS. .

  Returning to FIG. 9, the printing origin signal generation circuit 51 is for finely adjusting the position of the printing area by ink jet printing, and aligns the ink jet printing by the first ink jet printer 3 and the offset printing by the printing cylinder 2. It is provided for the purpose of performing. As described above, the first inkjet printing machine 3 is installed so that its printing position is separated by 1 L from the printing position of the lowermost printing cylinder 2c (see FIG. 3). It is difficult to install the first ink jet printing machine 3 without any error, and a slight shift may occur in the installation position.

  As shown in FIG. 11A, such a deviation in the installation position appears as a positional deviation in the ink jet printing region. Therefore, the print origin signal generation circuit 51 starts up the origin signal OS in order to correct the deviation. Are shifted to generate a reference signal (print origin signal POS) for inkjet printing (see FIG. 11B). The print origin signal generation circuit 51 is configured by a shift register that shifts the origin signal OS by a shift amount S times (S is an integer) of the period T (en) of the encoder signal EN, and the number of shifts (the value of S) is It is determined according to the adjustment amount input by the worker (see FIG. 9).

  As shown in FIG. 12, in the sub-scan print area signal generator 46, the counter 52 starts counting in response to the rise of the print origin signal POS, and counts the number of pulses of the encoder signal EN. When the count value CV1 of the counter 52 reaches the (sub) start position data VS, the comparison circuit 53 raises the coincidence signal CS1 to H level, and in response thereto, the subscan enable generation circuit 55 causes the subscan print area. The signal VPS is raised to H level. Thereafter, when the count value CV1 of the counter 52 reaches the (sub) end position data VE, the comparison circuit 54 raises the coincidence signal CS2 to the H level, and the subscan enable generation circuit 55 sets the subscan print area signal VPS to L. Fall to the level.

  The main scanning print area signal generator 47 shown in FIG. 8 is provided to generate a main scanning print area signal MPS that designates an ink jet printing area in the main scanning direction (width direction W of the running paper P).

  As shown in FIG. 13, the main scanning print area signal generation unit 47 generates an oscillation circuit 61 that generates a clock signal having a sufficiently higher frequency than the encoder signal EN, and the clock signal and encoder signal from the oscillation circuit 61. A phase synchronization circuit 62 that synchronizes the phase with EN and generates a reference clock (hereinafter referred to as “main scanning clock”) MCK in the main scanning direction, a counter 63 that counts the main scanning clock MCK, and a count value of the counter 63 A comparison circuit 64 that compares CV2 with the (main) start position data MS, a comparison circuit 65 that compares the count value CV2 with the (main) end position data ME, and a main scanning print area based on the outputs of the comparison circuits 64 and 65 The main scanning enable generation circuit 66 generates the signal MPS.

  Here, as shown in FIG. 10, the (main) start position data MS specifies the start point in the main scanning direction of the region where the white background 17 is to be formed. For example, the number of pulses of the main scanning clock MCK It is prescribed by. On the other hand, the (main) end position data ME specifies the end point of the white background 17 in the main scanning direction, and is defined by, for example, the number of pulses of the main scanning clock MCK, as in the (main) start position data MS. The

  As shown in FIG. 14, in the main scanning print area signal generation unit 47, the counter 63 starts counting in response to the rising edge of the encoder signal EN, and counts the number of clocks of the main scanning clock MCK. After that, as in the case of the sub-scanning print area signal generation unit 46, when the count value CV2 of the counter 63 reaches the (main) start position data MS, the main-scanning print area signal MPS is raised to H level. In response to the count value CV2 reaching the (main) end position data ME, the main scanning print area signal MPS falls to the L level.

  The recording head controller 49 shown in FIG. 8 is provided for generating the first control signal IN1 based on the sub-scanning print area signal VPS, the main-scanning print area signal MPS, and the like. The first control signal IN1 is used as a drive signal for driving the electrode 37 (see FIG. 7) of each recording head 31.

  As shown in FIG. 15, the recording head controller 49 converts a serially input main scanning print area signal MPS into a parallel signal and outputs the parallel signal, and a driving clock PC (see FIG. 15). 7) and the thinning circuit 72 for generating the thinning clock TC based on the encoder signal EN, the AND circuit 73 for obtaining the logical product of the thinning clock TC and the sub-scanning print area signal VPS, the output of the AND circuit 73, and the main scanning A NAND circuit group 74 that obtains the negative logical product of the print area signals MPS and outputs it to the upstream recording heads 31 (1-n) h (see FIG. 6), and a delay circuit 75 that delays the sub-scanning print area signal VPS. An AND circuit 76 for obtaining a logical product of the output of the delay circuit 75 and the thinned-out clock TCK, and the output of the AND circuit 76 and the main scanning mark Get the NAND of area signals MPS, and a NAND circuit group 77 to be output to the recording head 31 on the downstream side (1 to n) d (see FIG. 6).

  The thinning circuit 72 is for adjusting the adhesion amount (attachment frequency) of the ink droplets 36 in accordance with the traveling speed of the traveling paper P. As shown in FIG. 16, the thinning circuit 72 refers to the level of the drive clock PC at the rising timing of the encoder signal EN, and outputs the encoder signal EN without modulation when it is at the H level, If it is at the L level, the encoder signal EN pulse is thinned out.

  The delay circuit 75 corrects a writing position shift caused by a step B (see FIG. 6) between the upstream recording head 31 (1 to n) h and the downstream recording head 31 (1 to n) d. belongs to. Although the delay time DT in the delay circuit 75 is determined according to the size of the step B, in order to change the delay amount following the traveling speed of the traveling paper P, as shown in FIG. It is defined by the number of pulses.

  For this reason, when the running speed of the running paper P is low (the pulse width of the encoder signal EN becomes wide), the delay time DT of the sub-scanning print area signal VPS becomes long (see FIG. 17A), and conversely. When the traveling speed of the traveling paper P is high (the pulse width of the encoder signal EN becomes narrow), the delay time DT of the sub-scanning printing area signal VPS is shortened (see FIG. 17B). FIG. 17 illustrates a case where the delay time DT is defined as three pulses of the encoder signal EN.

  Next, operations of the first ink jet printer 3 and the first control unit 4 will be described with reference to FIG. Here, it is assumed that the area where the 1ch to 31 (5) d mch of the recording head 31 (3) h is located is designated as the printing area in the main scanning direction (width direction W of the running paper P). The operation will be described focusing on the printing control in the sub-scanning direction (the traveling direction R of the traveling paper P).

  As shown in FIG. 18, when the printing origin signal POS rises to the H level at the timing t0, the counter 52 of the sub-scanning printing area signal generation unit 46 starts counting, and counts the number of pulses of the encoder signal EN.

  When the count value CV1 of the counter 52 reaches the (secondary) start position data VS at the timing t1, the first control signals IN1 (3) h˜ () to the upstream recording heads 31 (3) h˜ (5) h 5) The level of h changes, and ink jet printing is started with the recording heads 31 (3) h to (5) h. Note that when the first control signals IN1 (3) h to (5) h are generated, the thinning circuit 72 performs a thinning process (see FIG. 16), and according to the running speed of the running paper P. Thin out pulses. At this time, as the traveling speed of the traveling paper P becomes slower (as the pulse width of the encoder signal EN becomes wider), the amount of thinning out pulses is increased, and the amount of ink droplets 36 adhering to the traveling paper P is reduced.

  When the delay time DT elapses at the timing t2, the levels of the first control signals IN1 (3) d to IN1 (5) d to the recording heads 31 (3) d to (5) d on the downstream side change, and recording is performed. Inkjet printing is started with the heads 31 (3) d to (5) d. As a result, the writing positions of the downstream recording heads 31 (3) d to (5) d and the upstream recording heads 31 (3) h to (5) h are aligned in a horizontal line, and the printed white background 17 is printed. To prevent the level difference from occurring. At this time, as in the case described above, the first control signals IN1 (3) d to (5) d are thinned out.

  When the counter 52 reaches the (secondary) end position data VE at the timing t3, the first control signal IN1 (3) h˜ () to the upstream recording heads 31 (3) h˜ (5) h is obtained. 5) h is fixed at the H level, and ink jet printing with the recording heads 31 (3) h to (5) h is stopped.

  Thereafter, when the delay time DT elapses at timing t4, the first control signals IN1 (3) h to (5) h to the downstream recording heads 31 (3) d to (5) d are fixed to the H level. Then, the inkjet printing by the recording heads 31 (3) d to (5) d is stopped. In this way, the start timing and end timing of ink jet printing are controlled, and white ink is sprayed onto appropriate positions on the running paper P in the entire recording heads 31 (3) h to (5) d.

  Thus, according to the present embodiment, since the writing timing of inkjet printing is controlled based on the encoder signal EN, the writing timing can be changed following the change in the running speed of the running paper P. For this reason, it becomes possible to always appropriately perform ink jet printing at a designated position on the running paper P without depending on fluctuations in the running speed.

  Further, the amount of the ink droplet 36 attached to the traveling paper P is adjusted by thinning out the pulses of the first control signals IN1 (3) h to (5) d (electrode 37 drive signals) according to the traveling speed of the traveling paper P. Therefore, even if the running speed of the running paper P changes, the ink droplets 36 can be attached with a substantially uniform density. Thereby, it is possible to suppress variation in the adhesion density of the ink droplets 36 in the ink jet printing region, and it is possible to suppress the occurrence of spots.

  In the actual printing process, test printing is executed prior to the printing process, and the position of the printing area by the first inkjet printer 3 is finely adjusted. Specifically, first, the first inkjet printing machine 3 is driven in a state where the origin signal OS and the printing origin signal POS shown in FIG. 11B are in the same phase (a state where the shift amount is 0), Perform a test print. Next, the worker confirms the printing state of the running paper P after the test printing, and grasps the degree of printing deviation in the sub-scanning direction (see FIG. 11A).

  Next, the worker inputs the position adjustment amount of the print area using an adjustment button (not shown) or the like with reference to the grasped deviation amount. The input of the adjustment amount at this time is performed, for example, in a manner such as lowering the printing position by several mm. Then, the printing origin signal generation circuit 51 (see FIG. 9) of the sub-scanning printing area signal generation unit 46 determines the value S shown in FIG. 11B according to the input adjustment amount, and shifts the printing origin signal POS. Determine the amount.

  In this way, the print start timing of the first inkjet printer 3 is delayed by a period corresponding to the adjustment amount, and the position of the print area is corrected to the correct position. The position adjustment of the ink jet printing area may be performed when the first ink jet printer 3 is installed, or may be performed immediately before the printing process (main printing).

  According to the above processing, the printing timing can be adjusted in accordance with the actual installation state of the first inkjet printer 3, so that the printing operations of the first inkjet printer 3 and the printing cylinder 2 can be easily synchronized. Thus, the print areas of both can be accurately aligned.

  In addition, since the origin signal OS is shifted in accordance with the encoder signal EN to generate the print origin signal POS (see FIG. 11B), the encoder signal is changed even if the travel speed of the travel paper P changes after the shift amount is determined. The rising timing of the print origin signal POS changes according to the expansion / contraction of the EN pulse width. For this reason, the printing timing of inkjet printing can be changed following the change in the running speed of the running paper P, and even if the running speed of the running paper P varies, the inkjet printing and the offset printing are always aligned. It becomes possible.

  Next, the details of the second inkjet printer 5 and its controller 6 will be described with reference to FIGS. Note that the write timing control and print width control are substantially the same as those of the first ink jet printer 3, and the description thereof is omitted.

  As shown in FIG. 19, the second inkjet printer 5 is configured by arranging a plurality of recording heads 81 arranged along the running direction R of the running paper P in both the running direction R and the width direction W ( 81 (1) to 81 (k) (k is a natural number of 2 or more)).

  Since the recording head 81 of the second ink jet printer 5 handles UV-curable ink having high viscosity, the head 81 uses a drop-on-demand ink jet head suitable for printing of high viscosity ink. In the drop-on-demand ink jet head, as shown in FIG. 20, the ink in the pressurizing chamber 86 is pressurized by applying a voltage to the piezoelectric element 85 to cause bending deformation, and the ink droplet 88 is ejected from the nozzle 82. To discharge.

  The recording heads 81 are multiplied to support high-speed printing, and each head 81 includes a plurality of nozzles 82 (1ch to j (j is a natural number of 2 or more)) along the traveling direction R as shown in FIG. ch) is provided. Also, a plurality of piezoelectric elements 85 shown in FIG. 20 are provided corresponding to each nozzle 82 and are configured to be individually driven. In the present embodiment, a second control signal IN2 generated by the second control unit 6 is used as a drive signal for the piezoelectric element 85.

  Taking the case where each recording head 81 is provided with 10 ch (multi-number = 5) nozzles 82 as an example, as shown in FIGS. 21 and 22, the second inkjet printer 5 is driven first by 1 ch and 6 ch. The nozzles 82 are simultaneously driven (see FIG. 22A), and then the nozzles 82 of each channel are driven while being delayed by a fixed delay time DT (s) (FIGS. 21 and 22B). To (e)).

  In this way, the ink droplets 88 ejected from the nozzles 82 are attached adjacent to the ink droplets 88 ejected from the nozzles 82 of the immediately preceding channel, so that even when the traveling paper P is traveling at high speed, the ink droplets 88 are left without any gaps. To attach. The ejection timing delay time DT (s) can be determined by the drive frequency of the piezoelectric element 85 / the number of multis.

  As mentioned above, although embodiment of this invention was described, this invention is not limited to those structures, A various change is possible within the range of the invention described in the claim.

  For example, in the above-described embodiment, the case where the present invention is applied to a tower type offset rotary press has been described as an example. However, the present invention is not limited to this, and can be widely applied to other types of rotary presses. It is possible to apply.

  Moreover, in the said embodiment, although the case where white ink was sprayed with the 1st inkjet printing machine 3 was illustrated, as long as printing of the printing cylinder 2 is made to stand out, the color of ink may be other than white. .

  Further, in the above embodiment, the recording head 31 of the first ink jet printing machine 3 is exemplified as an ink jet head that charges the ink droplet 36 when the ink droplet 36 is not attached to the traveling paper P. It is also possible to use an ink jet head in which 36 is charged and attached. In this case, an AND circuit group is used in place of the NAND circuit groups 74 and 77 in the recording head control unit 49 shown in FIG.

  In the above embodiment, as an example of generation of the print origin signal POS, the case where the print origin signal POS is raised after the origin signal OS is shown (see FIG. 11). Since it may be necessary to raise the print origin signal POS prior to the origin signal OS, the print origin signal POS may be generated as follows.

  That is, as shown in FIG. 23, when the maximum shift number is Z, the origin signal OS and the print origin signal POS are in phase with a shift amount of Z / 2 (FIG. 23 (a)). )), When the print origin signal POS is raised prior to the origin signal OS, it is shifted by the shift amount of (Z / 2) -adjustment amount (see FIG. 23 (b)). When the print origin signal POS rises with a delay, the print origin signal POS is shifted by a shift amount of (Z / 2) + adjustment amount (see FIG. 23C).

  Furthermore, in the above embodiment, the second ink jet printer 5 is arranged corresponding to one side of the running paper P, but like the first ink jet printer 3, it is arranged corresponding to both sides of the running paper P. Also good.

DESCRIPTION OF SYMBOLS 1 Printing system 2 (2c-2k) Printing cylinder 3 1st inkjet printing machine 4 1st control part 5 2nd inkjet printing machine 6 2nd control part 7 Paper feed unit 8 Ultraviolet lamp 11 Plate 12 Plate cylinder 13 Blanket cylinder 14 Encoder 15 Positioning sensor 17 White base 18 Inkjet printing area 19 1 page data 20 composite data 21 mask area 22 normal printing section 23 special printing section 31 (31 (1) h to 31 (n) d) recording head 32 nozzle 33 nozzle Arrangement area 35 Piezoelectric element 36 (36 ') Ink droplet 37 Electrode 38 Driver 39 Collection wall 40 Ink reservoir 41 High frequency power supply 46 Sub-scanning print area signal generating unit 47 Main-scanning printing area signal generating unit 49 Recording head control unit 51 Printing origin signal Generation circuit 52 Counter 53, 54 Comparison circuit 55 Sub-scan enable generation circuit 61 Oscillation Path 62 Phase synchronization circuit 63 Counter 64, 65 Comparison circuit 66 Main scan enable generation circuit 71 Serial / parallel conversion circuit 72 Decimation circuit 73, 76 AND circuit 74, 77 NAND circuit group 75 Delay circuit 81 (81 (1) -81 ( k)) Recording head 82 Nozzle 85 Piezoelectric element 86 Pressure chamber 88 Ink droplet

Claims (6)

A printing system for printing an image on traveling paper traveling in a predetermined direction,
A plurality of printing cylinders arranged along a traveling path of the traveling paper and printing an image while rotating;
A printing system comprising: an inkjet printing machine that is disposed upstream of the plurality of printing cylinders as viewed from the flow of the traveling paper and that prints an image by spraying ink onto the traveling paper.   2. The printing system according to claim 1, wherein the running paper is subjected to a background treatment by printing with the inkjet printing machine, and printing is performed by the printing cylinder on an area of the running paper on which the ground treatment is performed. .   3. The printing system according to claim 1, further comprising a control unit configured to control a printing timing of the inkjet printer based on an encoder signal indicating a rotation amount and a rotation speed of the printing cylinder. The starting point of the inkjet print area to be printed on the running paper is specified by the number of pulses of the encoder signal,
The said control part counts the pulse number of the said encoder signal, and when the count value corresponds with the pulse number designated as the said starting point, it starts printing of the said inkjet printer. 3. The printing system according to 3. The end point of the inkjet printing area is specified by the number of pulses of the encoder signal,
The printing system according to claim 4, wherein the control unit stops printing of the inkjet printer when the count value matches the number of pulses designated as the end point.   6. The apparatus according to claim 1, further comprising a second ink jet printer that is disposed on the downstream side of the plurality of printing cylinders as viewed from the flow of the traveling paper and that sprays glossy ink on the traveling paper. Printing system.

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