Printing control method and inkjet recording apparatus

Abstract

Provided are a printing control method and an inkjet recording device capable of keeping a contour position of printing, performed at a desired ink thickness, to be within an appropriate range. The printing control method, by which an ink that is cured by irradiating with prescribed energy rays is discharged onto a coating range (Wt) on a wiring substrate (S) so as to coat the same, comprises: a discharge amount specification step in which an ink discharge amount is determined such that the coating range (Wt) is set to have a prescribed coating thickness (h); and an adjustment step in which the ink discharge amount with respect to a peripheral edge section, of the coating range (Wt), within a prescribed width (We) from a boundary of the coating range (Wt), is changed and adjusted from the ink discharge amount according to the prescribed coating thickness (h).

Description

Technical Field

[0001] This invention relates to a printing control method and an inkjet recording apparatus.

Background Art

[0002] In an inkjet recording apparatus that ejects ink from nozzles to form an image or a structure, the ink droplets landing on a medium are likely to penetrate into the medium or spread on the medium. Therefore, a technique for adjusting the ink ejection pattern in the vicinity of the contour is known when forming a line or character with a clear contour (for example, Patent Documents 1 and 2).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, the conventional technology has a problem that it does not consider appropriately determining the thickness when forming a film having a thickness with the ejected ink.

[0005] An object of this invention is to provide a printing control method and an inkjet recording apparatus capable of keeping the contour position of printing performed with a desired ink thickness within an appropriate range.

Means for Solving the Problems

[0006] To achieve the above object, the invention according to claim 1 is a printing control method of ejecting and coating ink that cures by being irradiated with predetermined energy rays onto a set range on a medium, A discharge amount specifying step of determining an ink discharge amount so as to obtain a predetermined coating thickness with respect to the setting range, An adjustment step of changing and adjusting the ink discharge amount for the peripheral portion within a predetermined range from the boundary of the setting range within the setting range to an ink discharge amount corresponding to the predetermined coating thickness, including Look, In the adjustment step, it is determined whether it is within the predetermined range based on the presence or absence of ink ejection to peripheral pixels that are respectively in contact with each pixel that defines the presence or absence of ink ejection.

[0007] The invention according to claim 2 is, in the printing control method according to claim 1, The predetermined coating thickness is 15 μm or more.

[0008] The invention according to claim 3 is, in the printing control method according to claim 2, The predetermined coating thickness is 20 μm or more and 35 μm or less.

[0009] The invention according to claim 4 is, in the printing control method according to any one of claims 1 to 3, The predetermined coating thickness is equal to or greater than the height of the three-dimensional structure of the surface of the medium to be coated with the ink.

[0011] Claim 5 The invention described is, in the printing control method described in claim According to any one of 1 to 4 In the printing control method described, The pixel has a resolution of 1440 dpi or more.

[0012] Claim 6 The invention described is, in the printing control method according to any one of claims 1 to 5 In the printing control method described in any one of the above, In the adjustment step, the ink discharge amount to the peripheral portion is set to zero.

[0013] Claim 7 The invention described is, in the printing control method according to any one of claims 1 to 6 In the printing control method described in any one of the above, Within the setting range of the medium includes Surface characteristics regions of a plurality of different materials .

[0014] Claim 8 The invention described in the claim is in the printing control method according to any one of claims 1 to 5 In the method, In the adjustment step, the distribution of the ink ejection amount within the peripheral portion is determined according to the surface characteristics of the medium.

[0015] Claim 9 The invention described in the claim is in the printing control method according to any one of claims 1 to 8 In the method, In the adjustment step, the predetermined range related to the peripheral portion is determined according to the surface characteristics of the medium.

[0016] Claim 10 The invention described in the claim is in the printing control method according to any one of claims 1 to 9 In the method, In the adjustment step, the predetermined range is determined according to the predetermined coating thickness.

[0017] Claim 11 The invention described in the claim is in the printing control method according to any one of claims 1 to 10 In the method, The method includes a discharge operation step of discharging the ink with the ink discharge amount determined in the discharge amount specifying step and the adjustment step. In the discharge operation step, ink discharge is performed in a multi-drop method in which a plurality of droplets are continuously discharged and landed at the same pixel position, and the ink discharge amount is defined by the number of ink droplets continuously discharged in the multi-drop method.

[0018] Claim 12 The invention described in the claim is in the printing control method according to any one of claims 1 to 10 In the method, The method includes a discharge operation step of discharging the ink with the ink discharge amount determined in the discharge amount specifying step and the adjustment step. In the discharge operation step, the discharge operation is performed by a drive signal of a drive waveform pattern corresponding to the amount of ink droplets discharged at one time.

[0019] Claim 13 In the printing control method according to any one of claims 1 to 12 , the method includes a discharge operation step of discharging ink having an ink discharge amount determined in the discharge amount specifying step and the adjustment step, and in the discharge operation step, a coating thickness of at least 15 μm or more is formed on the medium by the ink discharged during one pass.

[0020] 14 Claim 13 In the printing control method according to any one of claims 1 to , the ink contains a gelling agent.

[0021] 15 Claim 14 In the printing control method according to any one of claims 1 to , the predetermined energy ray includes ultraviolet rays.

[0022] 16 Claim 15 In the printing control method according to any one of claims 1 to , the predetermined energy ray includes a ray having a wavelength for heating the ink on the medium.

[0023] 17 Claim 16 In the printing control method according to any one of claims 1 to , the medium on which the ink lands is a wiring board having an insulating substrate and a wiring conductor located on the insulating substrate, and the ink is a solder resist ink.

[0024] 18 Claim 17 In the printing control method according to any one of claims 1 to , the method includes a label forming step of forming a label on the medium coated with the ink.

[0025] ​​​​​​ Claim 19 The invention described in an ink ejection unit that ejects ink that cures when irradiated with a predetermined energy ray with respect to a set range on a medium; a control unit; and includes the control unit determines the ink ejection amount by the ink ejection unit so as to have a predetermined coating thickness with respect to the set range, within the set range, the ink ejection amount for the peripheral portion within a predetermined range from the boundary of the set range is changed and adjusted from the ink ejection amount corresponding to the predetermined coating thickness and In the change adjustment, it is determined whether it is within the predetermined range based on the presence or absence of ink ejection to peripheral pixels that are respectively in contact with each pixel that defines the presence or absence of ink ejection. It is an inkjet recording apparatus.

Effect of the Invention

[0026] According to the present invention, there is an effect that the contour position of printing performed with a desired ink thickness can be kept within an appropriate range by the ink ejection operation.

Brief Description of the Drawings

[0027]

Figure 1

Figure 2

Figure 3A

Figure 3B

Figure 4A

Figure 4B

Figure 5A

Figure 5B

Figure 6

Figure 7A

Figure 7B

Figure 7C

Figure 8

Figure 9

Figure 10

Mode for Carrying Out the Invention

[0028] Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a schematic front view for explaining an inkjet recording apparatus 1 according to an embodiment of the present invention. The inkjet recording apparatus 1 includes an inkjet head 20, a UV irradiation unit 42, a scanning unit 121, a conveyance table 131, and the like.

[0029] A wiring board S (medium) to which a film is to be formed by ink is placed on the conveyance table 131. The wiring board S is movable in a direction (conveyance direction) perpendicular to the surface shown in the figure in a state of being placed on the conveyance table 131. The wiring board S has a conductor (wiring conductor) forming a signal wiring on an insulating substrate. The conductor is not particularly limited, but is, for example, copper (copper foil) or the like. By the signal wiring protruding on the surface of the insulating substrate, the wiring board S has a three-dimensional structure. Here, the surface of the insulating substrate is a plane, and the perpendicular outward direction with respect to this plane is defined as upward.

[0030] The inkjet head 20 has nozzles and ejects ink from the nozzles onto the wiring board S. The UV irradiation unit 42 irradiates the wiring board S on which the ink has landed with ultraviolet light (UV light). The inkjet head 20 and the UV irradiation unit 42 are fixed to the scanning unit 121 and are moved (scanned) in the left - right direction (scanning direction; that is, the direction intersecting the moving direction of the carrier table 131, here the orthogonal direction) within the display surface by the scanning unit 121. With the combination of the movement of these scanning unit 121 and the carrier table 131, the inkjet recording apparatus 1 can form a two - dimensional film on the wiring board S. These movements may use, for example, a linear motor, and may also have rails or the like for guiding the moving range of the moving scanning unit 121 and / or the carrier table 131.

[0031] Figure 2 is a block diagram showing the functional configuration of the inkjet recording apparatus 1. The inkjet recording apparatus 1 includes a conveyance unit 10, an inkjet head 20 (ink ejection unit), a head drive control unit 30, a fixing unit 40, a control unit 50, a storage unit 60, an ink heating unit 70, a display unit 81, an operation reception unit 82, a communication unit 90, etc. The control unit 50 is communicatively connected to each unit via a bus or the like.

[0032] The conveyance unit 10 relatively moves the inkjet head 20 and the medium for forming an image (film), here the wiring board S. For example, the inkjet head 20 can move in a predetermined direction (scanning direction) with respect to the wiring board S, and the wiring board S can move in a direction (conveyance direction, sub - scanning direction) perpendicular to the scanning direction of the inkjet head 20.

[0033] The conveyance unit 10 has a scanning drive unit 12 and a conveyance drive unit 13. The scanning drive unit 12 moves the inkjet head 20 by scanning the above - mentioned scanning unit 121. The scanning drive unit 12 has, for example, a motor and moves the inkjet head 20 directly or indirectly via a fixture of the inkjet head 20. The movement may be performed along a rail or the like.

[0034] The conveyance drive unit 13 moves, for example, a base (conveyance table 131) on which the wiring board S is placed or a placement member such as a belt. It may be possible to land all the ink during one conveyance of the wiring board S in one direction (1 pass) (single pass). In this case, the conveyance drive unit 13 may only move a conveyance member such as an endless belt in a circular motion in one direction. When ink ejection onto the wiring board S is possible in a multi-pass manner in which the wiring board S is relatively moved so as to face the inkjet head 20 a plurality of times while landing the ink in each pass, the conveyance drive unit 13 can reciprocate the placement member.

[0035] The inkjet head 20 has a head drive unit 22 and a plurality of nozzles N, and ejects ink from the nozzles N according to a drive signal output by the head drive unit 22. The head drive unit 22 includes a discharge selection IC 28 (Integrated Circuit) and an electromechanical conversion element 223 or the like. The discharge selection IC 28 performs a switching operation so as to output a drive signal corresponding to the presence or absence of ink ejection from each nozzle N to the electromechanical conversion element 223 corresponding to each nozzle N based on the image data. The electromechanical conversion element 223 is, for example, a piezoelectric element, generates a shape change according to the input drive signal, and generates a pressure fluctuation in the ink in the ink flow path communicating with the nozzle N due to the shape change. The recording element 26 is constituted by the electromechanical conversion element 223 and the nozzle N.

[0036] The head drive control unit 30 includes a head control unit 31, a drive waveform signal generation circuit 32, etc., and outputs a drive waveform signal related to ink ejection or the like to the inkjet head 20 at a predetermined time period. The drive waveform signal related to ink ejection may be a combination of a plurality of pulse signals. Also, it may be possible to output drive waveform signals of a plurality of different waveform patterns (including changes in amplitude according to changes in the applied voltage value) corresponding to the ink ejection amounts respectively. Alternatively, it may be possible to output continuous drive pulses of a number corresponding to the amount of ink droplets per pixel. In this case, the ink droplets ejected by each drive pulse are combined during flight or landed within the same pixel range. The ink ejected from each nozzle to each pixel per pass (one cycle) is set to an ink droplet amount that can obtain the minimum thickness (for example, 15 μm) of the insulating film described later, taking into account the surface characteristics of the wiring substrate S, the temperature (viscosity characteristics) at the time of ink ejection, and the time interval from the landing of the ink droplets to the temporary adhesion by the UV light irradiation of the UV irradiation unit 42. Also, not only when ejecting ink, but it may be possible to output a non-ejection waveform pattern for stirring the ink within the nozzle N.

[0037] The ink ejected by the inkjet recording apparatus 1 of the present embodiment includes a solder resist ink and a marking ink. The solder resist ink is an ink ejected onto the wiring substrate S to form an insulating film (solder resist) on the wiring substrate S. Here, the solder resist ink is cured by irradiation with a predetermined energy ray, here, ultraviolet rays (UV) and infrared rays (heat). Also, the marking ink is an ink for forming a label or the like on the wiring substrate S or on the solder resist (that is, on the wiring substrate S covered with the solder resist ink). The label indicates, for example, the position information and identification information of components attached to each connection pad on the wiring substrate S, and the identification information of the wiring substrate S itself. The marking ink is cured by irradiation with ultraviolet rays.

[0038] The solder resist ink contains a compound having a thermosetting functional group. The thermosetting functional group may be various well-known ones, for example, those having an isocyanate group (especially two or more). Also, a polyfunctional isocyanate compound (blocked isocyanate) in which the isocyanate group is protected with a thermally dissociable blocking agent is preferable from the viewpoint of improving the resistance to high temperature and high humidity and the storage stability of the ink. The thermally dissociable blocking agent is not particularly limited, but is, for example, a compound containing at least one of an oxime-based compound, a pyrazole-based compound, and an active ethylene-based compound.

[0039] Alternatively, as the thermosetting functional group, for example, a (meth)acrylic group, particularly a (meth)acrylate compound having an imide group such as imide acrylate may be used. Since the imide group has a large polarity, strong adhesion to a strong metal (i.e., the wiring on the wiring board S) can be obtained. Also, due to its strong cohesive force, the influence on the metal adhesion is small even under high humidity.

[0040] On the other hand, as components related to the curing by irradiation with UV light in the solder resist ink and the marking ink, the ink contains a compound having a photopolymerizable functional group and a photopolymerization initiator. The photopolymerizable compound may be various compounds that polymerize or cause a crosslinking reaction to crosslink by irradiation with active energy rays (UV light) and have the effect of curing the ink, for example, radical polymerizable compounds and cationic polymerizable compounds. The polymerizable compound having an imide group such as the above-mentioned imide acrylate also has UV curability. The photopolymerization initiator corresponds to the above-mentioned type of photopolymerizable functional group (compound).

[0041] These inks also contain a gelling agent. The ink is in a gel state at room temperature, undergoes a phase change between a sol state according to temperature, and the viscosity changes rapidly. The gelling agent may be, for example, at least one of the compounds represented by the following general formula (G1) or (G2). General formula (G1): R 1 -CO-R 2 General formula (G2): R 3 -COO-R 4 In these formulas, R 1 ~R 4 each independently represents an alkyl chain having a linear portion of 12 or more carbon atoms and may have a branch. Such a gelling agent is dispersed in the cured film without inhibiting the curability of the ink. As a result, the moisture resistance of the formed ink film (solder resist or marking) is improved, and the penetration of moisture into the cured film is prevented. Further, the insulation reliability is also improved thereby. Further, the ink containing this gelling agent is also preferable in that it has good pinning properties and is likely to form a film that balances a fine line and a film thickness (that is, it is excellent in fine line reproducibility even when a film thickness is required).

[0042] The fixing unit 40 performs an operation of fixing the ink landed on the wiring board S. As described above, since the ink has thermosetting properties and curability by active energy rays (UV light), correspondingly, the fixing unit 40 has a UV irradiation unit 42 and a heat fixing unit 43. Although not particularly limited, here, the UV irradiation unit 42 is fixed to the scanning unit 121 together with the inkjet head 20 as described above and scanned to temporarily fix the ink landed on the wiring board S. The UV irradiation unit 42 has, for example, a light-emitting diode (LED) that emits ultraviolet rays, and emits ultraviolet rays (UV light) by applying a voltage to the LED to cause a current to flow. The UV irradiation unit 42 may be provided with a light shielding wall or the like for blocking leakage of UV light to a desired irradiation range outside if necessary.

[0043] Note that the configuration for emitting UV light in the UV irradiation unit 42 is not limited to an LED. The UV irradiation unit 42 may have, for example, a mercury lamp. Further, when the ink has a property of being cured and fixed by receiving active energy rays other than UV light, the UV irradiation unit 42 may have a well-known emission source (light source) that emits active energy rays for curing the ink instead of the configuration for emitting the above-described UV light.

[0044] The heating and fixing unit 43 has, for example, an infrared heater, and heats the wiring board S by emitting infrared light (the wavelength for heating the ink) to permanently fix the temporarily fixed ink. After the ink has landed and been temporarily fixed by the inkjet head 20 and the UV irradiation unit 42, the heating and fixing unit 43 is positioned, for example, such that permanent fixing is performed after the wiring board S is conveyed downstream in the conveyance direction. The heating and fixing unit 43 may be positioned within a housing that surrounds the range of the wiring board S and the portion of the conveyance member on which it is placed, so as to retain the generated heat inside the housing and efficiently maintain an appropriate curing temperature. In this case, it is not necessary to constantly operate the infrared heater during heating, and it is sufficient if the temperature is maintained with the housing wall surface or the like radiating appropriate infrared rays.

[0045] Note that the heating and fixing unit 43 does not have to be provided in the inkjet recording apparatus 1, and may be provided in a separate heating and fixing apparatus. Also, the heating and fixing apparatus may be a post-processing apparatus of the inkjet recording apparatus 1, and it may be possible to directly feed the wiring board S into a heating and fixing apparatus located, for example, on the extension line of the moving direction of the conveyance table 131 of the conveyance unit 10, or it may have a configuration in which the wiring board S removed from the conveyance table 131 of the inkjet recording apparatus 1 is set again in the heating and fixing apparatus, or the user may manually move the wiring board S.

[0046] The control unit 50 comprehensively controls the operations of each part of the inkjet recording apparatus 1. The control unit 50 has a CPU 51 (Central Processing Unit) and a RAM 52 (Random Access Memory). The CPU 51 is a hardware processor that performs various arithmetic processes and executes the program 61 stored in the storage unit 60. The RAM 52 provides a memory space for control to the CPU 51 and stores temporary data.

[0047] The storage unit 60 includes at least a non-volatile memory and stores the program 61 and the setting data. Examples of the non-volatile memory include a flash memory. Also, an HDD (Hard Disk Drive) or the like may be included in the non-volatile memory referred to here. Further, the storage unit 60 may include a RAM that temporarily stores the image data 62 indicating the formation (coating) range of the film to be formed and the drive data of the inkjet head 20 processed and generated based on the image data 62. The program 61 includes a control program related to the ink ejection control process and the coating range adjustment process described later. The setting data includes the thickness-corresponding information 63 including information related to the ink ejection amount corresponding to the thickness of the film to be formed. Although not particularly limited, the resolution of the information on the coating range (setting range) indicated by the image data 62 is preferably, for example, 1440 dpi (dots per inch) or more. Thereby, the contour line can be determined accurately. On the other hand, at this resolution, since the pixel size is about the same as or less than the coating thickness, it is difficult to ignore the influence of the spread of the landed droplets described later in the case of a normal insulating substrate or the material of the conductor forming the wiring.

[0048] The ink heating unit 70 heats the ink in the inkjet head 20 and the ink supply path to the inkjet head 20 and maintains it at an appropriate temperature. As described above, since the ink is assumed to be between sol and gel depending on the temperature, the fluidity of the ink is insufficient in the gel state at room temperature, and it is difficult to supply and eject the ink. The ink heating unit 70 keeps the ink in a sol state by heating the ink to an appropriate temperature, enabling supply and proper ejection. The appropriate temperature may be determined so that the ink is quickly dissipated by the wiring substrate S or the like after landing on the wiring substrate S and gels in an appropriate time. The ink heating unit 70 has, for example, a heating wire and a sheet member (such as rubber) heated by the heat generation of the heating wire, and the ink is heated by the sheet member coming into contact with the ink supply path or the like and transferring heat.

[0049] The display unit 81 displays various statuses, menus, etc. on the display screen based on the control of the control unit 50. The display unit 81 has, for example, a display screen and an LED (Light Emitting Diode) lamp. The display screen is not particularly limited, but is, for example, an LCD (Liquid Crystal Display). The LED lamp is lit (including a blinking operation) by the control unit 50 at a position and in a color corresponding to each situation according to, for example, the power supply situation and the occurrence situation of an abnormality.

[0050] The operation reception unit 82 receives an input operation from an external user or the like and outputs it to the control unit 50 as an input signal. The operation reception unit 82 has, for example, a touch panel and a push button switch. The touch panel may be positioned overlapping the display screen of the display unit 81. Also, the operation reception unit 82 may have various other operation switches.

[0051] The communication unit 90 controls the transmission and reception of data (signals) with external devices and the like according to a predetermined communication standard. The communication unit 90 performs communication control according to, for example, the standard of a LAN (Local Area Network). Also, the communication unit 90 may be such that peripheral devices and the like can be connected according to the standard of a USB (Universal Serial Bus).

[0052] Next, the ink ejection setting operation related to the printing control method in the inkjet recording apparatus 1 of the present embodiment will be described. The solder resist ink is used to provide an insulating film (solder resist) on the wiring board S. The coating range of this insulating film is determined (set range) according to the signal wiring and the like on the insulating substrate in the wiring board S and is held as image data 62. The insulating film (coating range) includes opening portions and cut portions such as a circular shape, an annular shape, a square shape, and a thin line according to the range where the signal wiring located on the insulating substrate forms connection pads connected to electronic components and external signal lines.

[0053] In addition, for reasons such as obtaining reliable insulation, the insulating film is required to have a minimum thickness, for example, a thickness of 15 μm or more. The thickness of the film (predetermined coating thickness) is not particularly limited, but is generally determined according to the application, the manufacturer, the thickness of the wiring, etc. Therefore, in the inkjet recording apparatus 1, any one of a plurality of predetermined candidates may be selected and set as the predetermined coating thickness. For example, the coating thickness may be set in 5-μm steps within a range such as 20 μm or more and 35 μm or less. Further, the set coating thickness may be, for example, equal to or greater than the thickness of the wiring (height of the three-dimensional structure).

[0054] FIGS. 3A and 3B are diagrams for explaining the thickness and coating range of the solder resist. As shown in FIG. 3A, after the solder resist ink lands on the wiring board S, it does not substantially penetrate into the wiring board S but accumulates on its surface to form a layer (coating I) with a thickness h. However, depending on the viscosity after landing and the water repellency (wettability) of the surface of the wiring board S (surface characteristics), etc., some spreading occurs. The width We of the spread is not negligible when the thickness h of the coating I is large. Therefore, when forming the coating I having the thickness h necessary for ensuring insulation as described above, it is likely to spread into the opening portion. This causes problems such as a reduction in the size of the connection pad. In addition, there is also a problem that the coating I in the fine wire shape becomes thicker than necessary.

[0055] In the inkjet recording apparatus 1 of the present embodiment, assuming the width We of the spread (the range within the width We is the peripheral portion of the present embodiment) with respect to the thickness h of the coating I (solder resist) to be formed, the image (coating range) data 62 is corrected so as to reduce the originally defined coating range Wt and eject the ink within the range W. Note that since the thickness h (coating thickness) does not necessarily become completely uniform due to the characteristics of the ink and the limit of fixing, it may be the average thickness within the range W. When the coating I is formed across regions with different heights of the wiring board S such as the presence or absence of wiring, the thickness h is the distance upward from each part of the wiring board S. That is, the film surface positions are different in the upward direction when the coating I with the same thickness h is formed in the part with wiring and the part without wiring.

[0056] The width We (predetermined range) may be uniformly determined when the minimum thickness of the coating film I is equal to or greater than the above, or may be determined according to the thickness h (coating thickness) as shown in FIG. 3B. Here, compared with the width We1 in the case of the thickness h1, the width We2 in the case of a larger thickness h2 is determined to be larger. That is, compared with the range W1 where ink is actually ejected in the case of the thickness h1, the range W2 where ink is actually ejected in the case of a larger thickness h2 is determined to be narrower. Further, the width We (peripheral portion) may be changed according to the shape of the boundary of the coating range Wt, for example, a linear shape or a concavo-convex shape. Specifically, in the concave portion of the coating range Wt, since ink is likely to overflow from multiple directions, the reduction range may be set larger than that of the linear portion, and in the convex portion of the coating range, the reduction range may be set smaller than that of the linear portion. For these, techniques related to the shape adjustment of fine lines known in the art can be applied.

[0057] FIGS. 4A, 4B, 5A, 5B, and 6 are diagrams showing examples of correction patterns of the image data 62 indicating the coating range. As shown in FIG. 4A, for example, when forming a substantially circular opening (unhatched portion), if there are pixels with no ink ejection among the surrounding pixels (peripheral pixels) in contact with the target pixel (based on the presence or absence of ink ejection), then, judging the boundary, the ink ejection amount of the target pixel (pixel at the peripheral portion) is adjusted to be reduced from the ejection amount (set value) corresponding to the thickness of the original coating film. Here, the adjustment is made so that the ink ejection amount is set to zero and ejection is not performed. That is, the target pixel B that contacts the boundary LA related to the pixel A located inside the opening with a point or a line is specified and changed to pixels where no ink ejection is performed. Similarly, as shown in FIG. 4B, all the pixels B and C (pixels at the peripheral portion) in contact with the boundary L (any of the pixels inside the opening) are changed to pixels where no ink is ejected. By correcting the image data 62 so as to uniformly reduce the ink ejection target pixels in this way, in reality, a part of the ink spreads to the area outside the ink ejection target pixels and an appropriate range is covered.

[0058] Even when a linear coating range is defined, pixels in the initial image data 62 shown in FIG. 5A that are in contact with the boundary line LD, that is, the pixel D shown in FIG. 5B, can be excluded from the ink ejection targets. However, when the coating (ejection range) has a fine line structure, if it is made too thin and the coating breaks, or even if it does not break but the coating thickness cannot be sufficiently obtained, the insulation may be reduced. In such cases, as shown in FIG. 6, instead of eliminating ink ejection (setting the ejection amount to zero) for the pixel D in contact with the boundary line LD, the ejection amount may be reduced somewhat from the original ejection amount (shown by the horizontal line hatching). When the width We is two pixels (N pixels), not only the pixels in contact with the target pixel but also the presence or absence of ink ejection may be determined within the range of two pixels (N pixels).

[0059] In addition to the method of controlling the ink droplet amount (landing amount) per pixel by varying the drive waveform pattern as described above, for example, a method of defining the ink droplet amount by the number of ink droplets continuously ejected by continuous drive pulses (multi-drop method) is known. As the drive waveform pattern, changes in pulse length and pulse amplitude can be considered.

[0060] FIGS. 7A to 7C are diagrams showing examples of drive waveforms. For example, with respect to the ink droplet amount ejected with the waveform shown in FIG. 7A, the ink droplet amount ejected with the drive waveform of FIG. 7B is smaller. Also, in the drive waveform pattern of the multi-drop method shown in FIG. 7C, by deleting a part of the five consecutive pulses, for example, a predetermined number from the beginning, the ink droplet amount corresponding to the number of pulses can be adjusted to land at the same pixel position (or may not coalesce) during flight.

[0061] FIG. 8 is a flowchart showing the control procedure by the control unit 50 of the coating range adjustment process executed by the inkjet recording apparatus 1 of the present embodiment. This coating range adjustment process is activated, for example, in response to an input operation to the user operation reception unit 82 or automatically when image data 62 defining the coating range is input.

[0062] When the coating range adjustment process is started, the CPU 51 (control unit 50) acquires and reads the input coating range data (step S101). The CPU 51 acquires data on the thickness of the coating film in the range to be coated according to the coating range data, and refers to the thickness correspondence information 63 to determine the ink ejection amount corresponding to the coating thickness and the reduction amount of the coating range (step S102; ejection amount specifying step). When the desired film thickness cannot be obtained by one-pass ejection, for example, the total ink ejection amount corresponding to the film thickness may be set by determining the ink ejection amount per pass and the number of passes. Information on the thickness of the coating film may be included in the coating range data, or may be separately set by an input operation from the operation reception unit 82 by the user.

[0063] The CPU 51 detects the boundary (line or pixel) of the coating range from the coating range data, and performs a range reduction process for changing and setting the range of the ink ejection target pixels in contact with the boundary (step S103; adjustment step). In the range reduction process, for example, as described above, the CPU 51 performs a change adjustment to reduce (including zero) the ink ejection amount for the ink ejection target pixels in contact with the boundary.

[0064] The CPU 51 ejects ink onto the wiring board S based on the coating range data corrected by the range reduction process to form an insulating film (solder resist) (step S104). The CPU 51 acquires a captured image of the formation range of the insulating film (step S105). The captured image of the formation range of the insulating film may be data obtained by separately photographing the wiring board S removed from the transport member with a photographing device, or the like. Alternatively, the inkjet recording apparatus 1 may have a photographing unit for photographing the wiring board S.

[0065] The CPU 51 analyzes the captured image to identify the coating range (coating range analysis process) (step S106). The CPU 51 determines whether the identified coating range is formed with a deviation within a range that satisfies the acceptable conditions with respect to the coating range indicated by the coating range data before correction (step S107). If it is determined that the deviation is not formed within the range that satisfies the conditions (in step S107, "NO"), the CPU 51 extracts the portion that does not satisfy the conditions, and changes the ink ejection range according to the corrected coating range data for the portion in accordance with the situation deviated from the conditions (step S108). Then, the process of the CPU 51 returns to step S104.

[0066] In the determination process of step S107, if it is determined that the coating range is formed with a deviation within the range that satisfies the conditions (in step S107, "YES"), the CPU 51 determines and stores the currently set corrected coating range data (step S109). Then, the CPU 51 ends the coating range adjustment process.

[0067] FIG. 9 is a flowchart showing the control procedure by the CPU 51 (control unit 50) of the ink ejection control process executed in the inkjet recording apparatus 1 of the present embodiment. This ink ejection control process is a control process for ejecting ink onto the wiring board S based on the coating range data determined in the above coating range adjustment process to form a coating film.

[0068] When the ink ejection control process starts, the CPU 51 acquires the determined coating range data (step S201). While outputting a control signal to the conveyance unit 10 to adjust and move the positional relationship between the inkjet head 20 and the wiring board S, the CPU 51 ejects a solder resist ink in an ink amount determined according to the coating range data (image data 62) to form a coating on the wiring board S (step S202; ejection operation step). The CPU 51 irradiates the ink on the wiring board S with UV light by the UV irradiation unit 42 to temporarily fix the ink (step S203). When the coating formation is performed in multiple passes, the processes of steps S202 and S203 are repeated the number of times corresponding to the number of passes. Note that the CPU 51 may perform the process of step S203 only once at the end after repeating the process of step S202 the number of times corresponding to the multiple passes.

[0069] The CPU 51 acquires the marking position data (step S204). The CPU 51 ejects a marking ink at a position corresponding to the marking position data to form a mark (step S205; marking formation step). The CPU 51 outputs a control signal to the UV irradiation unit 42 to irradiate with UV light and fix the marking ink on the wiring board S (step S206).

[0070] The CPU 51 outputs a control signal to the heat fixing unit 43 to heat the wiring board S and cure and permanently fix the ink (step S207). Note that the heat fixing process of step S207 may be performed before the process of step S204. Also, in this case and in the case of coating formation in multiple passes, not only the processes of steps S202 and S203 but also the process of step S207 may be repeated for each pass. Then, the CPU 51 ends the ink ejection control process.

[0071] FIG. 10 is a flowchart showing another example of the coating range adjustment process. The coating range adjustment process in this example is executed when the coating range is changed according to the position and shape of the wiring on the wiring board S without uniformly reducing it. In this coating range adjustment process, step S101a is added to the example shown in FIG. 8, and the process of step S108 is changed to the process of step S108a, and then the subsequent process is returned to step S103 instead of step S104. Other processes are the same, and the same reference numerals are given to the same process contents and detailed descriptions are omitted.

[0072] Following the process of step S101, the CPU 51 acquires the wiring pattern data of the wiring board S (step S101a). This wiring pattern data is referred to when determining the range reduction amount for each while comparing the wiring pattern and the coating range in the range reduction process of step S103. That is, for example, since the surface characteristics are different (non-uniform within the set range) between the boundary on the wiring (conductor) and the boundary on the outside of the wiring (insulating substrate), the CPU 51 determines the reduction amount (predetermined range) of the coating range separately for each and performs the range reduction process according to the surface characteristics of the medium. Also, instead of setting the ink ejection outside the uniformly reduced range to zero, the CPU 51 may determine the distribution of the ink ejection amount for the part that is changed and adjusted from the normal ejection amount due to the reduction. After the process of step S101a, the CPU 51 shifts the process to step S102.

[0073] Note that in the process of step S102, not limited to the boundary of the coating range, the distribution of the ink ejection amount for obtaining a substantially uniform film thickness within the coating range may be set non-uniformly according to the difference in surface characteristics between the wiring conductor and the insulating substrate.

[0074] When branching to "NO" in the determination process of step S107, the CPU 51 corrects the thickness correspondence information acquired in the process of step S102 in the process of step S108a (step S108a). Then, the CPU 51 returns the process to step S103 and executes the range reduction process again based on the corrected thickness correspondence information.

[0075] As described above, the printing control method of the inkjet recording apparatus 1 according to the present embodiment is a printing control method in which ink that cures by being irradiated with a predetermined energy ray is discharged and coated onto a setting range on the wiring board S. In this printing control method, a discharge amount specifying step of determining an ink discharge amount so as to obtain a predetermined coating thickness (thickness h) with respect to the setting range of the coating with ink, and an adjustment step of changing and adjusting the ink discharge amount for the peripheral portion within a predetermined range (width We) from the boundary of the setting range to a predetermined coating thickness with respect to the setting range in the setting range are included. By performing the adjustment of changing (decreasing) the ink discharge amount at the peripheral portion from the normal amount in this way, when obtaining a structure with a desired height, it is possible to reduce the amount of overhang outside the contour due to the spread of the ink and obtain an appropriate contour shape. In addition, troubles such as the exposed portion of the conducting wire being interrupted or buried can be suppressed. Therefore, the contour position of printing with an appropriate thickness can be kept within an appropriate range.

[0076] Further, the predetermined coating thickness is 15 μm or more. When forming a coating with a thickness equal to or greater than the film thickness required to ensure the insulating property by the insulating film, an appropriate contour can be maintained and the necessary functions and structures can be obtained.

[0077] Further, the predetermined coating thickness is 20 μm or more and 35 μm or less. When forming a functional film such as an insulating film that is generally used, the necessary functions of the coating can be obtained while appropriately maintaining the shapes of thin linear portions, opening portions, etc.

[0078] Further, the predetermined coating thickness may be equal to or greater than the height of the three-dimensional structure of the surface of the wiring board S coated with ink. When forming a coating that completely embeds the three-dimensional structure according to the application, the thickness may be determined according to the structure and may be made a necessary and sufficient thickness.

[0079] In the adjustment step, it is determined whether it is at the peripheral edge of the coating range based on the presence or absence of ink ejection to the peripheral pixels respectively positioned in contact with each pixel that defines the presence or absence of ink ejection. That is, without directly detecting the boundary itself through image processing or the like, by determining whether a pixel is in contact with the boundary sequentially based on the presence or absence of ink ejection of the surrounding pixels, the process can be simplified.

[0080] Also, the pixel may have a resolution of 1440 dpi or more. At this resolution, the pixel size becomes 18 μm or less, which is approximately the same as the thickness of the insulating film. Therefore, even considering the viscosity of the ink and the timing of temporary fixing, the influence of spreading becomes so large that it cannot be ignored. By applying the above technology in such a case, it is possible to more effectively achieve both maintaining the film thickness and the shape.

[0081] In the adjustment step, the ink ejection amount to the peripheral edge is set to zero. That is, in the inkjet recording apparatus 1 using the printing control method of the present embodiment, by simply not performing ink ejection to the peripheral edge of the coating range, it is possible to easily and more reliably suppress the landed ink from overflowing and spreading from the original coating range without adjusting the ink ejection amount in multiple steps.

[0082] Also, the surface characteristics within the ink ejection setting range of the wiring board S are non-uniform. That is, in the wiring board S, the water repellency / wettability is different between the insulating substrate portion and the wiring conductor portion. In such a case, by adjusting the ink ejection amount at the peripheral edge, it is possible to effectively reduce the landed ink from overflowing and spreading from the setting range.

[0083] In the adjustment step, the distribution of the ink ejection amount within the peripheral edge may be determined according to the surface characteristics of the wiring board S. By adjusting the ink ejection amount according to the difference in water repellency / wettability between the insulating substrate portion and the wiring conductor portion as described above, in the inkjet recording apparatus 1 using the printing control method of the present embodiment, it is possible to achieve both a more uniform and accurate coating thickness and coating range.

[0084] Further, in the adjustment step, the width We related to the peripheral portion may be determined according to the surface characteristics of the wiring board S. Thereby, in the inkjet recording apparatus 1 using the printing control method of the present embodiment, the coating range can be adjusted with higher accuracy. Therefore, it is possible to prevent the opening from becoming too narrow or the fine line from being interrupted.

[0085] Further, in the adjustment step, a predetermined range (width We) of the peripheral portion may be determined according to a predetermined coating thickness. When the film thickness is large, it tends to spread greatly outside the ejection range according to the viscosity (fluidity) of the ink. Therefore, by setting the width We of the peripheral portion according to the film thickness, the coating range can be determined more appropriately.

[0086] Further, the printing control method of the present embodiment includes a discharge operation step of discharging the ink having the ink discharge amount determined in the discharge amount specifying step and the adjustment step. In the discharge operation step, ink discharge is performed by a multi-drop method in which a plurality of droplets are continuously discharged and landed at the same pixel position, and the ink discharge amount is defined by the number of ink droplets continuously discharged by the multi-drop method. By using the multi-drop method, it is possible to determine the ink discharge amount according to the number of output times without greatly changing the waveform pattern related to ink discharge. Further, even when the ink discharge amount is not changed in multiple steps, in the multi-drop method, the ink discharge amount per pass can be easily increased, so that the film thickness that can be formed in one pass can be increased. Also, it is easier to operate stably than discharging large droplets in a single discharge operation.

[0087] Alternatively, in the discharge operation step, the ink may be discharged by a drive signal having a drive waveform pattern corresponding to the ink discharge amount. When the ink discharge amount per pass can be appropriately adjusted by selecting a drive waveform pattern even without using the multi-drop method, the drive waveform pattern may be selected and switched so as to discharge a desired ink droplet amount.

[0088] Also, in the ejection operation step, it may be possible to form a coating thickness of at least 15 μm or more on the wiring board S with the ink ejected in one pass. Since a coating (especially an insulating film) with the required minimum thickness can be formed in one pass, the formation time can be shortened and the process becomes easier. Therefore, the productivity of the inkjet recording apparatus 1 using this printing control method is improved.

[0089] Also, the ejected ink contains a gelling agent. In order to suppress the fluidity of the ink as much as possible after landing to form a three-dimensional structure, the viscosity after landing can be increased by including a gelling agent in the ink.

[0090] Also, the predetermined energy rays related to the fixing and curing operation include ultraviolet rays. By irradiating the ink with ultraviolet rays to cure the ink after landing, the ink can be cured promptly after landing, and the spread of the ink on the wiring board S can be suppressed.

[0091] Also, the predetermined energy rays related to the fixing and curing operation include those with a wavelength that heats the ink on the wiring board S. By heat-fixing the ink, the coating structure of the ink can be firmly cured and stabilized. Also, by using an ink that undergoes thermosetting and heat-fixing, it is possible to prevent the ink from sol-gelling and losing its shape and flowing down due to a simple temperature increase later.

[0092] Also, the medium on which the ink lands is a wiring board S having an insulating substrate and a wiring conductor located on the insulating substrate, and the ink is a solder resist ink. That is, by applying the above technology when forming an insulating film with a predetermined film thickness of solder resist ink on the wiring board S, it is possible to obtain the required insulating performance and appropriately form fine connection pads and the like.

[0093] In addition, the inkjet recording apparatus 1 that uses the printing control method of the present embodiment includes a label forming step of forming a label on a wiring board S coated with ink. By forming an insulating film within an appropriate range as described above, the label formed thereon can also be stably formed at an appropriate position.

[0094] Further, the inkjet recording apparatus 1 of the present embodiment includes an inkjet head 20 that discharges ink that cures when irradiated with predetermined energy rays (UV light and infrared rays) with respect to a set range on the wiring board S, and a control unit 50. The control unit 50 (CPU 51) determines the ink discharge amount by the inkjet head 20 so as to have a predetermined coating thickness with respect to the set range. Further, the control unit 50 determines the boundary of the set range and changes and adjusts the ink discharge amount for the peripheral portion within a predetermined range (width We) from the boundary from the ink discharge amount corresponding to the predetermined coating thickness. According to this inkjet recording apparatus 1, by performing an adjustment to change (decrease) the ink discharge amount at the peripheral portion from the normal, when obtaining a structure with a desired height, the amount of overhang outside the contour due to the spread of the ink can be reduced, and an appropriate contour shape can be obtained. In addition, troubles such as the exposed portion of the conducting wire being interrupted or filled can be suppressed. Therefore, in the inkjet recording apparatus 1, the contour position of printing with an appropriate thickness can be kept within an appropriate range.

[0095] Note that the present invention is not limited to the above-described embodiment, and various modifications are possible. For example, in the above-described embodiment, the range (coating range) of the insulating film that has partially openings or cuts and spreads two-dimensionally as a whole has been described, but the insulating film may have a linear (including annular) structure as a whole. Further, the insulating film formed on the wiring board may be separated at a plurality of locations.

[0096] In addition, in the above-described embodiment, the case where a solder resist ink is ejected onto a wiring board to form an insulating film has been described as an example. However, the present invention is not limited thereto as long as it is formed in a three-dimensional shape with a certain thickness on a medium. For example, raised characters or figures formed by ink for image formation may be used.

[0097] In addition, in the above-described embodiment, the solder resist ink has been described as having both properties of being cured by UV light and heat curing. However, it may have either one of these properties, or it may have a curing property by electromagnetic waves of other wavelengths.

[0098] In addition, it is preferable that the ink has a low viscosity during ejection and rapidly increases in viscosity after landing. However, it does not necessarily have to undergo a phase change between sol and gel.

[0099] In addition, film formation may be performed in multiple passes (multi-pass). In this case, the ink may be ejected in a similarly reduced range in each pass.

[0100] In addition, in the above-described embodiment, the image data 62 with a resolution of 1440 dpi or more has been described as being used. However, it is not necessarily required to be 1440 dpi or more.

[0101] In addition, in the above-described embodiment, the boundary position of the coating range is sequentially determined based on whether ink is ejected from adjacent pixels, and the ink ejection range is reduced. However, after analyzing the image data 62 in advance to detect all boundary positions, pixels adjacent to the boundary may be specified, and a process of reducing (setting to zero) the ink ejection amount of the pixels may be performed.

[0102] In addition, the film thickness exemplified as 15 μm to 35 μm is a value considering the function as an insulating film. However, when forming other functional films, a film thickness range corresponding to the function of the functional film is set, and the ink ejection amount corresponding to the film thickness may be determined.

[0103] In the above-described embodiment, as methods for controlling the amount of ink droplets (landing amount) per pixel, examples include a method of changing the drive waveform pattern and amplitude, and the multi-drop method. However, the present invention is not limited to these. For example, by adjusting the pressure of the ink in a state where no drive pulse is applied (usually set to a negative pressure so that the ink does not leak), the state of the ink liquid surface (meniscus) in the nozzle N can be adjusted, or the ink droplet amount can also be adjusted by changing and adjusting the drive frequency. Alternatively, the ink droplet amount can also be adjusted by applying a drive pulse of an appropriate non-ejection waveform pattern in advance before the waveform pattern for ink ejection and then applying the drive pulse of the drive waveform pattern while giving vibration to the meniscus. In addition, the specific configurations, details of the processing operations, procedures, etc. shown in the above-described embodiment can be appropriately changed without departing from the spirit of the present invention. The scope of the present invention includes the scope of the invention described in the claims and its equivalent scope.

Industrial Applicability

[0104] This invention can be used for an ink ejection control method and an inkjet recording apparatus.

Explanation of Reference Numerals

[0105] 1 Inkjet recording apparatus 10 Conveying unit 12 Scanning drive unit 121 Scanning unit 13 Conveying drive unit 131 Conveying stage 20 Inkjet head 22 Head drive unit 223 Electromechanical conversion element 26 Recording element 28 Ejection selection IC 30 Head drive control unit 31 Head control unit 32 Drive waveform signal generation circuit 40 Fixing unit 42 UV irradiation unit 43 Heat fixing unit 50 Control Unit 51 CPU 52 RAM 60 Memory Unit 61 Program 62 Image Data 63 Correspondence Information 70 Ink Heating Unit 81 Display Unit 82 Operation Reception Unit 90 Communication Unit N Nozzles S Wiring Board W, W1, W2 Ranges We, We1, We2 Widths Wt Coating Range

Claims

1. A printing control method for ejecting and coating ink that cures when irradiated with a predetermined energy ray with respect to a set range on a medium, comprising: a discharge amount specifying step of determining an ink discharge amount so as to obtain a predetermined coating thickness with respect to the set range; an adjustment step of changing and adjusting the ink discharge amount for a peripheral portion within a predetermined range from a boundary of the set range within the set range to an ink discharge amount corresponding to the predetermined coating thickness; including in the adjustment step, determining whether it is within the predetermined range based on the presence or absence of ink discharge to peripheral pixels respectively located in contact with each pixel that respectively defines the presence or absence of ink discharge; a printing control method.

2. The printing control method according to claim 1, wherein the predetermined coating thickness is 15 μm or more.

3. The printing control method according to claim 2, wherein the predetermined coating thickness is 20 μm or more and 35 μm or less.

4. The printing control method according to any one of claims 1 to 3, wherein the predetermined coating thickness is equal to or greater than the height of the three-dimensional structure of the surface of the medium coated with the ink.

5. The printing control method according to any one of claims 1 to 4, wherein the pixel has a resolution of 1440 dpi or more.

6. The printing control method according to any one of claims 1 to 5, wherein in the adjustment step, the ink discharge amount to the peripheral portion is set to zero.

7. The printing control method according to any one of claims 1 to 6, wherein within the set range of the medium, regions of a plurality of materials having different surface characteristics are included.

8. The printing control method according to any one of claims 1 to 5, wherein in the adjustment step, the distribution of the ink discharge amount within the peripheral portion is determined according to the surface characteristics of the medium.

9. The printing control method according to any one of claims 1 to 8, wherein in the adjustment step, the predetermined range related to the peripheral portion is determined according to the surface characteristics of the medium.

10. The printing control method according to any one of claims 1 to 9, wherein in the adjustment step, the predetermined range is determined according to the predetermined coating thickness.

11. including a discharge operation step of discharging the ink having the ink discharge amount determined in the discharge amount specifying step and the adjustment step, in the discharge operation step, performing ink discharge by a multi-drop method in which a plurality of droplets are continuously discharged and landed at the same pixel position, and the ink discharge amount is defined by the number of droplets of the ink continuously discharged by the multi-drop method. The printing control method according to any one of claims 1 to 10.

12. Including a discharge operation step of discharging the ink having the ink discharge amount determined in the discharge amount specifying step and the adjustment step, In the discharge operation step, the discharge operation is performed by a drive signal of a drive waveform pattern corresponding to the amount of ink droplets discharged at one time. The printing control method according to any one of claims 1 to 10.

13. Including a discharge operation step of discharging the ink having the ink discharge amount determined in the discharge amount specifying step and the adjustment step, In the discharge operation step, a coating thickness of at least 15 μm or more is formed on the medium by the ink discharged during one pass. The printing control method according to any one of claims 1 to 12.

14. The printing control method according to any one of claims 1 to 13, wherein the ink contains a gelling agent.

15. The printing control method according to any one of claims 1 to 14, wherein the predetermined energy ray includes ultraviolet rays.

16. The printing control method according to any one of claims 1 to 15, wherein the predetermined energy ray includes a wavelength that heats the ink on the medium.

17. The medium on which the ink lands is a wiring board having an insulating substrate and a wiring conductor located on the insulating substrate, The ink is a solder resist ink. The printing control method according to any one of claims 1 to 16.

18. The printing control method according to any one of claims 1 to 17, including a label forming step of forming a label on the medium coated with the ink.

19. An ink ejection unit that ejects ink that cures when irradiated with a predetermined energy ray with respect to a set range on a medium, A control unit, Comprising, The control unit, Determines the ink discharge amount by the ink ejection unit so as to have a predetermined coating thickness with respect to the set range, Within the set range, the ink discharge amount for the peripheral portion within a predetermined range from the boundary of the set range is changed and adjusted from the ink discharge amount corresponding to the predetermined coating thickness, In the change adjustment, it is determined whether or not it is within the predetermined range based on the presence or absence of ink discharge to peripheral pixels respectively in contact with each pixel that respectively defines the presence or absence of ink discharge. An inkjet recording apparatus.

Images