JP2005066909A - Printing equipment for building board - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide printing equipment for a building board, which uses an inkjet printing technology for preventing a nozzle from being clogged with ink, even in the existence of the nozzle which is not used for a printing pattern at all. <P>SOLUTION: This printing equipment for the building board forms a flashing dot by daringly ejecting the ink into a printed image to be formed, from a part of the nozzle which does eject the ink in terms of the printing pattern, to such a degree as not to adversely affect the printed image. This enables a natural design expression with a unique feel, wherein color dots with three kinds of densities such as a high density, a middle density and a low density are mixed together. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a building board printing apparatus using an ink jet printing technique, and more particularly to a building board printing apparatus capable of preventing nozzle clogging.

  In order to eliminate the tendency of ink thickening, a conventional ink jet printing apparatus performs an operation of ejecting ink droplets not related to printing from a nozzle, which is called “flushing” (for example, , See Patent Document 1). In such a flushing operation, ink droplets are necessarily ejected, and therefore, by performing this operation before the nozzles are clogged, the occurrence of ink clogging can be effectively prevented.

  In the case of a normal serial printer, the flushing operation is performed by moving the print head to a portion where the printing operation is not performed. In the case of a head-fixed line printer, the flushing operation is performed between the plate and the plate. This is done by using the time between intervals corresponding to the travel interval.

JP 2003-170616 A

  However, when printing a building board having a large printing surface, there may be nozzles that are less frequently used to reproduce various color patterns during printing on one board. There are many. For such a less frequently used nozzle, there is a sufficient risk that the ink state at that portion will tend to increase in viscosity, and this means that the time corresponding to the travel interval between the plates described above is reduced. There is no guarantee that the ink thickening transition tendency that occurs partially can be surely eliminated by simply performing flushing using it.

  SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and an object of the present invention is to provide a building board printing apparatus using ink-jet printing technology that does not cause ink clogging even if there is a nozzle that is not used on a printed pattern. And

  A building board printing apparatus according to the present invention includes a pattern pattern storage unit that stores a pattern pattern to be printed on a building board, a control unit that controls ejection of ink from a nozzle in accordance with an input drive signal, and printing. A first drive signal for ejecting ink and a drive signal generating circuit for generating a second drive signal for ejecting ink to the extent that printing is inconspicuous for preventing ink clogging, and a pattern read from the pattern pattern storage means An ink jet type comprising a selection circuit that outputs to the control means the first drive signal for the nozzles that eject ink and the second drive signal for a part of the nozzles that do not eject ink according to the pattern belongs to.

  Moreover, the building board printing apparatus of this invention controls the discharge of the ink from several nozzles about one dot according to the pattern pattern memory | storage means which memorize | stores the pattern pattern printed on a building board, and the input drive signal. A control means; a drive signal generating circuit for generating a first drive signal for ejecting ink for printing and a second drive signal for ejecting ink to an extent that is not noticeable as printing for preventing ink clogging; The first drive signal is set so as to have a density corresponding to the pattern read from the pattern pattern storage means, and at least for some nozzles that do not output the first drive signal when the density is not the highest density. And a selection circuit for outputting the second drive signal to the control means.

  Further, the second drive signal is less frequently output for black ink than for other color inks, thereby reducing the influence (dullness) on the color tone.

  In addition, the drive signal generation circuit includes two elements that generate a first drive signal and one that generates a second drive signal, and the selection circuit is provided for each nozzle and includes two drive signal generation circuits. By selectively outputting the two common driving signals to the control means of each nozzle, the circuit scale can be reduced.

  According to the present invention, in order to take an active measure for preventing nozzle clogging, a flushing dot is formed by ejecting ink droplets in a print image to be formed to an extent that does not adversely affect the print image. Further, the effect of preventing ink clogging in the nozzle portion is further ensured.

  In addition, by accurately forming color dots and flushing dots on a traveling building board (movable printing area), for example, color dots having three types of density, high density, medium density, and low density. It is possible to express natural designs with a unique texture with a mixture of.

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

  FIG. 1 is a diagram showing a configuration of a building board printing apparatus according to an embodiment of the present invention. FIG. 1A is a diagram illustrating an example of the first embodiment, and FIG. 1B is a diagram illustrating an example of the change. The construction board printing apparatus according to the first embodiment mainly includes a pattern pattern storage means 11, a selection circuit 12, a drive signal generation circuit 13, and a control means 14.

  This building board printing apparatus performs inkjet printing on a printing surface of a building board, and the pattern pattern storage means 11 is an inkjet nozzle for printing a design pattern on the printing surface of a building board. This is a memory such as a RAM (Random Access Memory) that stores the discharge pattern. The selection circuit 12 is a first drive signal that ejects ink for printing to the nozzles that eject ink from the drive signal generation circuit 13 based on the ejection pattern of each inkjet nozzle read from the pattern pattern storage unit 11. In addition, a second drive signal for discharging ink is generated to prevent ink clogging with respect to a part of the nozzles that do not discharge ink and is inconspicuous as printing. The drive signal generation circuit 13 outputs the generated first drive signal and second drive signal to the control means 14. The control means 14 determines whether the input drive signal is a first drive signal for ejecting ink for printing or a second drive signal for ejecting ink to the extent that it is not noticeable for printing in order to prevent ink clogging. Specifically, a piezoelectric element or the like is used to control the ejection of ink from the nozzles depending on whether the ink is discharged.

  FIG. 1 (b) is a diagram showing a configuration of a variation of the first embodiment. This construction board printing apparatus mainly includes a pattern pattern storage means 21, a selection circuit 22, a drive signal generation circuit 23, And control means 24. In the case of this variation, the selection circuit 22 uses the first drive signal and the second drive signal, which are two signals generated by the drive signal generation circuit 23, for each inkjet nozzle stored in the pattern pattern storage means 21. Based on the discharge pattern, it is output to the control means 24. In the case of the example shown in FIG. 1 (a), the drive signal generation circuit 13 is required for each nozzle. In this example shown in FIG. It is only necessary to provide two drive signal generation circuits 23, one that generates the first drive signal and one that generates the second drive signal.

  FIG. 2 is a diagram illustrating an arrangement example of the building board printing apparatus according to the first embodiment. While the building board is conveyed in the building board conveying direction, a cyan print head HC, a magenta print head HM, a yellow print head HY, and a black print head HK are provided on the upper part. Each print head HC, HM, HY, and HK is a fixed head separation method.

  FIG. 3 is a diagram illustrating an example of nozzle arrangement on the lower surface of the print head of the building board printing apparatus according to the first embodiment. The nozzles are arranged in a straight line in the direction orthogonal to the building board conveyance direction at intervals of the nozzle pitch p (= V / f, V = building board conveyance speed, f = ink discharge frequency), and the nozzles are further arranged in the building board conveyance direction. Three nozzles are arranged at intervals of the pitch p.

  The operation of the three nozzles with a time difference so that one color dot is completely formed when the horizontal print line of the building board passes the position immediately below the horizontal line of nozzle No. (3). Control the timing.

  Specifically, when the density is low (one color dot is formed by one drop of ink), only the nozzle No. (3) is driven. In the case of density (one color dot is formed with two ink drops), nozzle No. (3) is driven following nozzle No. (2). The time difference Δt = p / V. When the density is high (one color dot is formed by three ink drops), each nozzle is driven in the order of nozzle No. (1) → (2) → (3).

  FIG. 4 is a diagram for explaining the printing operation of the building board printing apparatus according to the first embodiment. For example, in the printing rectangular area A1 (p × p), the nozzle No. (1) is driven at t = 1, the nozzle No. (2) is driven at t = 3, and the nozzle No. (at t = 5). By driving 3), high-density color dots (black circles) are printed. The shaded circles indicate color dots with high density, and the white circles indicate color dots with low density.

  Similarly, three nozzles No. (1) and (2) are also provided for each of the printed rectangular regions B1, C1, D1,... Parallel to the horizontal direction of the building board (the direction orthogonal to the building board conveyance direction). ) And (3) are controlled. The timing range by the timer is t = 0 to t = 6, and is controlled by the pulse count.

  Moreover, about the to-be-printed rectangular area A2 in the longitudinal direction of the building board (the building board transport direction) following the to-be-printed rectangular area A1, the time when the front end line of the design surface of the building board has reached the time t = 2, Printing control is performed in the same manner as A1 with a new reference time t = 0. The same applies to B2, C2, D2,... In parallel with A2.

  Further, the difference in the number of superimposed ink droplets appears as a slight difference between the density difference of the printed color dots and the dot diameter.

  By executing the above print control for each color print head shown in FIG. 1, each color print image with each color dot structure is formed. In principle, each color print image is printed so as not to overlap.

  FIG. 5 is a diagram illustrating an example of pixel formation of the building board printing apparatus according to the first embodiment. In the present embodiment, one pixel is formed by a composition of 16 color dots composed of 4 color dots vertically and horizontally. However, the arrangement of the color dots of each color is for convenience and is expressed by appropriately arranging.

  In the upper left of the drawing, a segmented region of one pixel configuration with 16 color dots is shown. The A line, the B line, the C line, and the D line are the rectangular areas to be printed that are arranged in parallel on the respective printing lines in the vertical direction of the building board (the building board conveyance direction).

  In the center of the drawing, six printed lines parallel to the vertical direction of the building board (conveying direction of the building board) for four printing lines parallel to the horizontal direction of the building board (direction orthogonal to the conveying direction of the building board) The color dot arrangement example of each color printed with respect to a rectangular area is shown.

  Such dot images (◯, Δ, □, ●) for each color are independently formed for each color print head shown in FIG. One color dot is formed by the control shown in FIG. As a print image to be formed, every time it passes through each print head, a [C (cyan)] color image → [C + M (magenta)] color image → [C + M + Y (yellow)] color image → [C + M + Y + K (black)] Color images are formed in sequence.

  Now, assuming that one nozzle set handles three nozzles juxtaposed in the vertical direction of the building board shown in FIG. 3 (the conveying direction of the building board), each printed line is dedicated to it. The nozzle set will be in charge of printing.

  A brief description will be given as to when the flushing operation is performed for one nozzle set.

  In FIG. 5, when a print line in which the color dots constituting one pixel are not printed once in each print head is examined, four continuous rectangular areas with diagonal lines in the drawing are obtained. The travel period of the building board corresponding to this non-printing part is specified as the flushing period. That is, the flushing operation cannot be performed at the time of printing as a matter of course, and is therefore performed at the non-printing time.

  In the present embodiment, it is assumed that the flushing is performed at the building board traveling time corresponding to the non-printed portion marked with the mark ▽ in FIG. That is, flushing is executed at a time corresponding to a rectangular area located approximately in the center between the color dots and the next color dot.

  When the non-printing area is continuous over two pixels, the flushing time is specified with a predetermined interval such as the second column of the first pixel and the second column of the next pixel. Further, since there is a concern about the influence (dullness) on the color tone of K dots, the frequency of flushing is reduced, and control is performed so that flushing is not continuously performed on the same printing line.

  In addition, from the pattern design design like the rock surface generally used for building boards used as outer wall boards, the flushing dots (mixed dots) formed by the above flushing operation have an adverse effect on the building board designs. Although it is known from the results of the test that this is relatively rare, a flashing dot formation simulation is executed in advance for confirmation.

  Also, regarding the operation timing (corresponding to the printing timing) of the three nozzles constituting one set of nozzles, not all nozzles are necessarily used, so only two or one nozzle is used. In this case, the density of the printed dots is intentionally changed to high so that the remaining one or two nozzles are used with an appropriate frequency. Even if it does in this way, the sense of incongruity outstanding conspicuously on a design is not expressed.

  As described above, the idea that the flushing dots that do not form the formal print image are intentionally formed in the print image has a small print dot diameter (for example, about 0.28 mm when the resolution is 90, and about 0.28 mm when the resolution is 180). 14 mm, about 0.07 mm when the resolution is 360, and about 0.035 mm when the resolution is 720.) In addition, the design surface of the building board is extremely large (for example, about 455 mm × 1818 mm), and The surface of the ceramic building board (cement board) is not smooth, and countless minute irregularities are formed to bring about irregular reflection effects and make the presence of flushing dots inconspicuous. Based on the fact that it acts on. And by devising the formation state of the flushing dots, when constructed as a building board, the eyes of the person who looks at the outer wall at a considerable distance cannot recognize the existence of the flushing dots at all. Is possible.

  In the present embodiment, the influence on the color tone is further reduced by making the above-mentioned flushing dot diameter smaller than the printing dot diameter.

  FIG. 6 is a diagram illustrating a specific example of the drive signal generation circuit of the building board printing apparatus according to the first embodiment. The charge control pulse (1) input to the input terminal IN1 operates the constant current charging circuit including the transistors Q2 and Q3 and the resistor R1 via the level shift transistor Q1, and charges the capacitor C with a constant current value. As a result, the terminal voltage of the capacitor C rises to a predetermined voltage, and substantially the same voltage is output to the output terminal OUT via the current amplifier circuit composed of the transistors Q11, Q12, Q13, and Q14.

  Similarly, the charge control pulse (3) input to the input terminal IN3 operates the constant current charging circuit including the transistors Q5 and Q6 and the resistor R2 via the level shift transistor Q4, and causes the capacitor C to have a constant current value. Charge. As a result, the terminal voltage of the capacitor C rises to a predetermined voltage, and substantially the same voltage is output to the output terminal OUT via the current amplifier circuit composed of the transistors Q11, Q12, Q13, and Q14.

  The discharge control pulse (2) input to the input terminal IN2 activates a constant current discharge circuit including the transistors Q7 and Q8 and the resistor R3, and discharges the capacitor C with a constant current. As a result, the terminal voltage of the capacitor C drops to a predetermined voltage, and substantially the same voltage is output to the output terminal OUT via the current amplifier circuit composed of the transistors Q11, Q12, Q13, and Q14.

  Similarly, the discharge control pulse (4) input to the input terminal IN4 operates the constant current discharge circuit including the transistors Q9 and Q10 and the resistor R4, and discharges the capacitor C with a constant current. As a result, the terminal voltage of the capacitor C drops to a predetermined voltage, and substantially the same voltage is output to the output terminal OUT via the current amplifier circuit composed of the transistors Q11, Q12, Q13, and Q14.

  The charge control pulse (1) and the discharge control pulse (2) generate a first drive signal for forming a print dot, and the charge control pulse (3) and the discharge control pulse (4) form a flushing dot. A second drive signal is generated.

  FIG. 7 is a diagram illustrating a specific example of a control waveform according to the first embodiment. Examples of control pulses (IN1 to IN4) and driving voltage waveforms are shown. FIG. 7A shows only the nozzle No. (1) in the nozzle set for three consecutive pixel areas on the print line corresponding to the D line of the C dot image shown in FIG. The drive voltage waveform and the control pulses (IN1 to IN4) in the case of using and printing color dots with low density are shown. In this case, each nozzle No. (1), (2), (3) is flushed once, for a total of 3 times. The maximum voltage value when printing is ON is 40 V, for example, and the maximum voltage value when flushing is ON is 25 V, for example.

  FIG. 7 (b) shows a control waveform when including the case of forming high density color dots using the three nozzles No. 1 (2) and (3) in the nozzle set. Is shown. In this case, flushing is performed once for nozzle No. (1).

  The present invention is not limited to the above embodiment.

It is a figure which shows the structure of the building board printing apparatus by one embodiment of this invention. It is a figure which shows the example of arrangement | positioning of the building board printing apparatus by 1st Embodiment. It is a figure which shows the nozzle arrangement example of the lower surface of the printing head of the building board printing apparatus by 1st Embodiment. It is a figure explaining printing operation of the building board printer by a 1st embodiment. It is a figure which shows the example of pixel formation of the building board printing apparatus by 1st Embodiment. It is a figure which shows the specific example of the drive signal generation circuit of the building board printing apparatus by 1st Embodiment. It is a figure which shows the specific example of the control waveform of 1st Embodiment.

Claims (4)

Pattern pattern storage means for storing a pattern to be printed on a building board;
Control means for controlling ejection of ink from the nozzles in accordance with an input drive signal;
A drive signal generating circuit for generating a first drive signal for ejecting ink for printing and a second drive signal for ejecting ink to an extent that is not noticeable as printing for preventing ink clogging;
In accordance with the pattern read from the pattern pattern storage means, the first drive signal is supplied to the control means for the nozzles that eject ink, and the second drive signal is used for a part of the nozzles that do not eject ink. An inkjet type building board printing apparatus comprising a selection circuit for outputting. Pattern pattern storage means for storing a pattern to be printed on a building board;
Control means for controlling ejection of ink from a plurality of nozzles for one dot in accordance with an input drive signal;
A drive signal generating circuit for generating a first drive signal for ejecting ink for printing and a second drive signal for ejecting ink to an extent that is not noticeable as printing for preventing ink clogging;
The first drive signal is set to have a density corresponding to the pattern read from the pattern pattern storage means, and if the density is not the highest density, the first drive signal is not output to at least some of the nozzles. An inkjet type building board printing apparatus comprising: a selection circuit that outputs a second drive signal to the control unit.   3. The building board printing apparatus according to claim 1, wherein the second drive signal is output less frequently for black ink than for other color inks. 4. The drive signal generation circuit is composed of two components, one generating a first drive signal and one generating a second drive signal, and the selection circuit is provided for each nozzle and is common to the two drive signal generation circuits. The building board printing apparatus according to claim 1 or 2, wherein the two drive signals are selectively output to the control means of each nozzle.

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