Production method for marked products

Abstract

To provide a production method for marked products with an increased processing speed.SOLUTION: The method for producing a marked product comprises: conveying an object along a conveyance passage; arranging shield mechanism for forming a regular passage of a laser beam by blocking part of the laser beam generated by a laser oscillator, between the laser oscillator and the conveyance passage; arranging a mask member on which a light transmission pattern corresponding to the design of marking to be performed on the object is formed, between the laser oscillator and the conveyance passage; and radiating the laser beam from the laser oscillator on the object that is conveyed.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to a method for producing a marked product. [Background technology]

[0002] Patent Document 1 discloses a laser marking device. The laser marking device of Patent Document 1 uses the same scanning means and lens to scan and process the surface of an object with multiple lasers. The scanning means has a first scanning means for scanning in a first direction and a second scanning means for scanning in a direction substantially perpendicular to the first direction, and the first scanning means is located in an optical path where the optical paths of the multiple lasers converge. The object is controlled to move in the same direction as one of the scanning means. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2023-025326 A Summary of the Invention [Problem to be solved by the invention]

[0004] In the laser marking device of Patent Document 1, the drawing area of ​​an object that is controlled to move in one direction is divided into multiple areas, and multiple laser light sources are assigned to these. According to Patent Document 1, by reducing the drawing area per beam in this way, productivity is improved. However, in the method of forming dots on the object surface while scanning the laser light, it is necessary to reduce the moving speed of the object in accordance with the drawing speed of the dots. For this reason, further improvement in the processing speed by laser marking is desired.

[0005] The present disclosure aims to provide a method for producing marked products with improved processing speed. [Means for solving the problem]

[0006] A method for producing a marked product according to a first aspect of the present disclosure includes transporting an object along a transport path, disposing a shielding mechanism between a laser oscillator and the transport path to form a regular path of the laser light by shielding a portion of the laser light generated from the laser oscillator, disposing a mask member between the laser oscillator and the transport path, the mask member having a design pattern formed thereon that transmits or shields the laser light corresponding to the design of the marking to be made on the object, and irradiating laser light from the laser oscillator to the object being transported.

[0007] A method for producing a marked product according to a second aspect of the present disclosure is the method for producing a marked product according to the first aspect, wherein the laser oscillator is an excimer laser oscillator, a UV laser oscillator, a CO2 laser oscillator, or a YAG laser oscillator.

[0008] A method for producing a marked product according to a third aspect of the present disclosure is a method for producing a marked product according to the first or second aspect, wherein the shielding mechanism is a photomask having a regular pattern consisting of shielding areas that block laser light and transparent areas that transmit laser light.

[0009] A method for producing a marked product according to a fourth aspect of the present disclosure is a method for producing a marked product according to any one of the first to third aspects, wherein the shielding mechanism is a member having a regular pattern formed thereon, the regular pattern being composed of shielding areas that block the laser light and transparent areas that transmit the laser light, and the shielding areas are formed by a highly reflective mirror.

[0010] A method for producing a marked product according to a fifth aspect of the present disclosure is a method for producing a marked product according to any one of the first to fourth aspects, wherein the mask member is a photomask on which the design pattern is formed, the design pattern consisting of a shielding area that blocks the laser light and a transparent area that transmits the laser light.

[0011] A method for producing a marked product according to a sixth aspect of the present disclosure is a method for producing a marked product according to any one of the first to fifth aspects, wherein the mask member is a member on which the design pattern is formed, the design pattern consisting of a shielding area that blocks the laser light and a transparent area that transmits the laser light, and the shielding area is formed of a highly reflective mirror.

[0012] A method for producing a marked product according to a seventh aspect of the present disclosure is a method for producing a marked product according to any one of the first aspect to the sixth aspect, in which the shielding mechanism and the mask member are integrally constructed.

[0013] A method for producing a marked product according to an eighth aspect of the present disclosure is a method for producing a marked product according to any one of the first aspect to the seventh aspect, wherein the object comprises a resin container body including a bottom portion, a side portion extending upward from the outer peripheral edge of the bottom portion, a mouth portion defining an upper opening, and a shoulder portion continuous with the side portion and the mouth portion, and a recessed portion is formed in at least one of the bottom portion, side portion, and shoulder portion, and irradiating laser light to the object being transported includes irradiating the laser light to the inner surface of the recessed portion.

[0014] A method for producing a marked product according to a ninth aspect of the present disclosure is a method for producing a marked product according to any one of the first aspect to the eighth aspect, in which the recessed portion is formed in the side surface portion.

[0015] A method for producing a marked product according to a tenth aspect of the present disclosure is a method for producing a marked product according to any one of the first aspect to the ninth aspect, wherein the recessed portion extends around the entire periphery of the side portion.

[0016] A method for producing a marked product relating to an eleventh aspect of the present disclosure is a method for producing a marked product relating to any of the first aspect to the tenth aspect, wherein the recessed portion extends from the outer peripheral edge of the bottom portion to the upper end of the side portion.

[0017] A method for producing a marked product according to a twelfth aspect of the present disclosure is a method for producing a marked product according to any one of the first aspect to the eleventh aspect, wherein the inner surface of the recess forms a flat surface facing the external space of the container body at the innermost position, and irradiating the inner surface of the recess includes irradiating the laser light to the flat surface.

[0018] A method for producing a marked product according to a thirteenth aspect of the present disclosure is a method for producing a marked product according to any one of the first to twelfth aspects, wherein the object comprises a resin container body including a bottom portion, a side portion extending upward from the outer peripheral edge of the bottom portion, a mouth portion defining an upper opening, and a shoulder portion continuous with the side portion and the mouth portion, and at least one of the bottom portion, side portion, and shoulder portion has a protrusion formed thereon that protrudes from the outer surface, and irradiating the object being transported with laser light includes irradiating the laser light near the protrusion.

[0019] A marked product relating to a fourteenth aspect of the present disclosure comprises a resin container body including a bottom portion, a side portion extending upward from the outer peripheral edge of the bottom portion, a mouth portion defining an upper opening, and a shoulder portion continuous with the side portion and the mouth portion, and at least one of the bottom portion, side portion, and shoulder portion is formed with a marking area including a collection of multiple recesses or a collection of multiple protrusions formed on an outer surface, the marking area displaying a predetermined design, and a recessed portion, and the marking area is formed on the inner surface of the recessed portion.

[0020] A marked product according to a fifteenth aspect of the present disclosure is the marked product according to the fourteenth aspect, wherein the side portion is formed with the marking area and the recessed portion.

[0021] A marked product according to a sixteenth aspect of the present disclosure is the marked product according to the fourteenth or fifteenth aspect, wherein the recessed portion extends around the entire periphery of the side portion.

[0022] A marked product according to a seventeenth aspect of the present disclosure is a marked product according to any one of the fourteenth to sixteenth aspects, wherein the recessed portion extends from the outer peripheral edge of the bottom portion to the upper end of the side portion.

[0023] The marked product relating to an 18th aspect of the present disclosure comprises a resin container body including a bottom portion, a side portion extending upward from the outer peripheral edge of the bottom portion, a mouth portion defining an upper opening, and a shoulder portion continuous with the side portion and the mouth portion, and at least one of the bottom portion, side portion and shoulder portion is formed with a marking area including a collection of multiple recesses or a collection of multiple protrusions formed on the outer surface, the marking area displaying a predetermined design, and a protrusion protruding outward beyond the marking area in the vicinity of the marking area. Effect of the Invention

[0024] According to the present disclosure, a method for producing marked products is provided that has improved process speeds. [Brief description of the drawings]

[0025] [Figure 1] 1A to 1C are diagrams illustrating a method for producing a marked product according to an embodiment. [Diagram 2] FIG. 4 is a plan view showing a configuration example of a shielding mechanism. [Diagram 3] FIG. 4 is a plan view showing an example of the configuration of a mask member. [Figure 4] 1 is a flowchart showing an example of the flow of a method for producing a marked product. [Diagram 5] FIG. 2 shows a first example configuration of an object and a marked product. [Figure 6] FIG. 13 shows a second example configuration of an object and a marked product. [Figure 7] FIG. 13 shows a third example configuration of an object and a marked product. [Figure 8] FIG. 11 shows a fourth example configuration of an object and a marked product. [Figure 9] A diagram showing a fifth example configuration of an object and a marked product. [Figure 10A] FIG. 13 is a diagram showing a photomask pattern according to a modified example. [Figure 10B] FIG. 13 is a diagram showing a photomask pattern according to another modified example. [Figure 10C] FIG. 13 is a diagram showing a photomask pattern according to still another modified example. [Figure 10D] FIG. 13 is a diagram showing a photomask pattern according to still another modified example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0026] Hereinafter, a method for producing a marked product according to an embodiment of the present disclosure will be described with reference to the drawings.

[0027] <1. Overall composition> 1 is a diagram illustrating a method for producing a marked product, including a laser marking method according to an embodiment of the present disclosure (hereinafter, also simply referred to as a "marking method"). According to the marking method according to this embodiment, the processing time required for each marking is shortened compared to conventional marking methods. Therefore, the marking method can be preferably applied to a conveying line in which a plurality of objects are conveyed continuously, and marked products can be efficiently produced.

[0028] The object to be marked is not particularly limited, and examples thereof include resin products, metal products, electronic components (e.g., circuit elements sealed with resin), edible products, glass products, ceramic products, wood products, leather products, paper products, textile products, rubber products, and packaging materials (e.g., plastic films). The surface of the object may be made of any material, but it is preferable that the material has a property that the color and gloss change by irradiation with laser light to an extent that the marked design is visible. However, the object may be processed so that the marking area to be marked is colored in advance and the visibility of the marked design is improved by removing the color, or the marking may be colored in that area after marking. Furthermore, the object may be made of a material containing a component that changes color when irradiated with laser light. A typical example of a resin product is a PET bottle. A typical example of an edible product is a tablet (sugar-coated tablet, plain tablet, coated tablet, etc.) or a capsule.

[0029] The marking design to be applied to an object is not particularly limited, and may include, for example, letters, designs, one-dimensional information codes such as barcodes, or two-dimensional information codes such as QR codes (registered trademark).

[0030] Hereinafter, a method for marking a design including a barcode on the side of the container body of a PET bottle 1 will be described as an example. The PET bottle 1 includes, but is not limited to, a transparent container body made of polyethylene terephthalate and a cap made of a thermoplastic resin attached to the upper opening of the container body. The PET bottles 1 are loaded in a line on a conveyor line (conveyor path) 10 composed of a belt conveyor or the like, and move continuously in a predetermined direction along the conveyor line 10. The conveyor line 10 is configured to convey, for example, about 600 to 1000 PET bottles 1 per minute.

[0031] A marking device 2 for carrying out the method for producing marked products according to this embodiment is installed to the side of the conveyor line 10. The marking device 2 is a device that uses laser light to mark a predetermined design on the side of a PET bottle 1 that passes a predetermined position, and includes a laser oscillator 20, a field lens 21, a shielding mechanism 22, a mask member 23, and a projection lens 24. The conveyor line 10 and the marking device 2 constitute a production system for producing marked products.

[0032] The laser oscillator 20 is a device that generates a laser beam. The laser oscillator 20 is not particularly limited, and any of an excimer laser oscillator, a UV laser oscillator, a CO2 laser oscillator, and a YAG laser oscillator can be used. When the object is a PET bottle 1, the laser oscillator 20 is preferably an excimer laser oscillator. According to the study by the present inventors, when the wavelength of the laser beam is about 193 nm to 315 nm, the transmittance of the laser beam through a transparent polyethylene terephthalate plate having a thickness of about 0.2 mm is about 0%T to 0.07%T, and it can be said that the absorbency of the laser beam through the polyethylene terephthalate plate is high. On the other hand, when the wavelength of the laser beam is 355.5 nm, the transmittance of the laser beam through the same polyethylene terephthalate plate is about 75%T, and it can be said that the absorbency of the laser beam through the polyethylene terephthalate plate is relatively low. The polyethylene terephthalate plate is a sample cut out from an existing PET bottle, but it is considered that the transmittance of the laser beam does not depend on the thickness of the sample. The excimer laser is a laser that uses a mixed gas of rare gas, halogen, etc., and has typical wavelengths of 193 nm, 248 nm, 308 nm, and 351 nm, making it suitable for marking PET bottles 1. The wavelength of the laser pulse of the laser oscillator 20 (excimer laser oscillator) according to this embodiment is 308 nm.

[0033] In this way, the laser oscillator 20 can be selected so as to generate laser light of an appropriate wavelength depending on the object to be marked.

[0034] In addition, the irradiation time of one shot of various laser oscillators is, for example, about 27 nanoseconds for an excimer laser oscillator, about 100 nanoseconds for a TEA-CO2 laser oscillator, and about 50 nanoseconds for a nanosecond solid-state UV laser oscillator. Thus, the excimer laser oscillator is also preferable from the viewpoint of the short irradiation time of one shot. The repetition frequency of the laser oscillator 20 can be appropriately adjusted according to the conveying speed of the object to be marked. For example, when marking 1000 PET bottles 1 per minute, irradiation of 17 shots per second is required. In this case, by setting the frequency of the laser oscillator 20, which has a higher repetition frequency, to 17 Hz, it is possible to continuously mark the object moving on the conveying line 10.

[0035] The field lens 21 is an optical system member disposed between the laser oscillator 20 and the shielding mechanism 22. The field lens 21 aligns the traveling direction of the laser light generated from the laser oscillator 20 and adjusts the size of the laser beam emitted from the field lens 21. In the example of FIG. 1, the laser light is aligned so as to be parallel to the optical axis of the projection lens 24 described below, and the laser beam formed by the aligned laser light is adjusted to have a size of 60 mm×20 mm. For example, when the magnification of the projection lens 24 is 2 times, the size of the marking formed on the side of the PET bottle 1 is 30 mm×10 mm.

[0036] The shielding mechanism 22 forms a regular path of the laser light by shielding a part of the laser light generated from the laser oscillator 20 or the laser beam emitted from the field lens 21. As a result, the laser beam passing through the shielding mechanism 22 forms a plurality of laser beams parallel to the optical axis of the projection lens 24 described later. The shielding mechanism 22 can be formed of, for example, a photomask 22A as shown in FIG.

[0037] The photomask 22A is a plate-like member having a rectangular shape in a plan view, and has a surface 220. The photomask 22A is arranged so that the surface 220 shown in FIG. 2 is perpendicular to the traveling direction of the laser light. A plurality of regularly arranged square-shaped transmission regions 221 and shielding regions 222 are formed on the surface 220. The transmission regions 221 transmit the laser light, respectively. The shielding regions 222 shield the laser light, and transmit very little or no light at all. As a result, the photomask 22A as a whole forms a regular path for the laser light. That is, the intensity distribution of the laser light on a surface perpendicular to the traveling direction of the laser light is a regular pattern. Such a photomask 22A can be formed, for example, by laminating a chrome film in a predetermined pattern on one side of a synthetic quartz substrate. That is, the transmission regions 221 can be formed in a portion of the substrate on which the chrome film is not laminated, and the shielding regions 222 can be formed of chrome films.

[0038] The size of one transmission region 221 is formed so that the size of the laser light passing through it is sufficiently smaller than the minimum size of the slit 231 of the mask member 23 described later. For example, a plurality of slits 231 are formed in the mask member 23 described later, and in this embodiment, the width of the narrowest slit among them is 0.25 mm. The laser beam passing through this slit is preferably in 10 rows or more in the width direction of the slit, more preferably in 20 rows or more, and even more preferably in 30 rows or more. Although it depends on the magnification of the projection lens 24, the optical readability of the barcode formed on the PET bottle 1 is improved by forming the path of the laser light with the above-mentioned density with respect to the size of the slit 231. The minimum width of the slit 231 and the range of the preferable number of rows (density) of the laser beam with respect to the size of the slit 231 are examples in the above embodiment, and may change depending on the design of the marking and the object to be marked.

[0039] The photomask 22A is not limited to the above example, and the transmission area 221 and the shielding area 222 can be formed using other materials and can be formed in other patterns. The photomask 22A is an example of the shielding mechanism 22. The shielding mechanism 22 is not limited to a photomask as long as it shields a part of the incident laser light and forms a regular path of the laser light as a whole. Here, "shielding a part of the laser light" includes absorbing a part of the laser light and reflecting a part of the laser light to prevent it from passing to the conveying line 10 side. Another example of the shielding mechanism 22 is a member in which the shielding area 222 is formed of a high reflection mirror. Examples of the high reflection mirror include a dielectric multilayer mirror and a metal mirror. The dielectric multilayer mirror is a reflective member that is composed of a dielectric film with a high refractive index and a dielectric film with a low refractive index stacked alternately, and shows a high reflectance for a predetermined wavelength. The metal mirror is a reflective member that reflects light by a metal coating on the surface, and examples of the metal mirror include an aluminum mirror, a silver mirror, a gold mirror, and the like, among which an aluminum mirror is preferable. For example, the shielding mechanism 22 may be a member obtained by forming a plurality of through holes (as the plurality of transmission regions 221) or a plurality of transmission hole parts made of a material that transmits laser light in a regular pattern in the high reflection mirror. The shielding mechanism 22 may also be a member obtained by laminating the high reflection mirror as the shielding region 222 on one side of a base material that transmits laser light.

[0040] The mask member 23 according to the present embodiment is disposed between the shielding mechanism 22 and the projection lens 24 or between the object. FIG. 3 shows an example of the mask member 23. The mask member 23 in FIG. 3 is a plate-like member having a rectangular shape in a plan view on which a design pattern 230 corresponding to the design of the marking is formed, and is formed of, for example, metal, and has a thickness that does not transmit laser light. In the example shown in FIG. 3, the design pattern 230 corresponding to the barcode is formed by a plurality of transmission areas shown in black. Each of these transmission areas is formed by a rectangular or linear slit 231 penetrating the mask member 23, and allows the incident laser light to pass through. As described above, the minimum size of the slit 231 is sufficiently larger than the cross-sectional area of ​​each incident laser beam, and the multiple laser beams emitted from the shielding mechanism 22 pass through the slit 231 as multiple laser beams as they are. The mask member 23 according to the present embodiment is disposed so that the surface shown in FIG. 3 faces and contacts the back surface of the surface 220 of the shielding mechanism 22.

[0041] The projection lens 24 is an optical system member disposed between the mask member 23 and the object. The projection lens 24 converges the multiple laser beams emitted from the mask member 23 onto a predetermined range on the side of the PET bottle 1. In the example of FIG. 1, the projection lens 24 causes the multiple laser beams to converge onto an area of ​​30 mm vertical by 10 mm horizontal on the side of the PET bottle 1. The energy of the multiple laser beams that reach the side of the PET bottle 1 is 600 mJ / cm. 2or more. However, this range is an example of a case where a barcode is marked on a PET bottle 1 by an excimer laser oscillator, and may vary depending on the type of laser, the marking design, and the object to be marked. Each laser beam that reaches the side of the PET bottle 1 causes the polyethylene terephthalate on the side of the PET bottle 1 to disappear, forming fine irregularities on the surface. The part where the irregularities are formed loses transparency due to the diffusion of visible light and turns white. As a result, a marking area M is formed on the side of the PET bottle 1, which displays the marking design according to the reduced design pattern 230.

[0042] The fine irregularities are formed of a plurality of recesses formed corresponding to the transmission region 221 of the shielding mechanism 22 and protrusions surrounding each of the recesses, forming a regular pattern. The irregularities have a size and height difference at the micro level. From the viewpoint of improving the visibility of the marking design, it is preferable that the number of recesses formed per unit area is larger.

[0043] <2. Flow of production method for marked products> 4 is a flow chart showing an example of the flow of each process when carrying out the above-mentioned method for producing a marked product.

[0044] First, a mask member 23 on which a design pattern 230 corresponding to a desired marking design is formed is prepared (step S1). The size of the design pattern 230 does not need to match the actual size of the marking to be formed on the object, and can be set to a size that takes into account reduction by the projection lens 24.

[0045] Next, the shielding mechanism 22 and the mask member 23 are arranged in this order between the laser oscillator 20 and the transport line 10, more specifically, between the field lens 21 and the projection lens 24 (step S2). In this embodiment, the above-mentioned photomask 22A is arranged as the shielding mechanism 22. From the viewpoint of more accurately forming an image of the laser light on the object surface, it is preferable that the photomask 22A and the mask member 23 are arranged so as to overlap each other.

[0046] Next, the conveyance line 10 starts conveying the plurality of PET bottles 1 (step S3). The conveyance speed may be constant. The frequency of the laser oscillator 20 can be appropriately set in accordance with the conveyance speed.

[0047] Next, marking by the marking device 2 is started (step S4). That is, the laser oscillator 20 starts irradiating the PET bottle 1 being conveyed with a laser beam. Marking starts, for example, when the PET bottle 1 passes in front of the projection lens 24 for the first time. The production system according to this embodiment is provided with an object detection sensor (not shown). The object detection sensor is configured to output a detection signal to a controller (not shown) that controls the operation of the marking device 2 when it detects that each PET bottle 1 approaches the projection lens 24. The controller controls the timing of irradiating each PET bottle 1 with a laser beam from the laser oscillator 20 based on the detection signal. The object detection sensor is not particularly limited, and any type of sensor, such as a photoelectric sensor, a laser sensor, an ultrasonic sensor, or an image sensor, can be used. In addition, the position where the object detection sensor is installed is not particularly limited.

[0048] Thereafter, one shot of laser light is repeatedly applied in the same manner to each of the PET bottles 1 that sequentially pass in front of the projection lens 24. This repetitive marking process stops if a certain period of time continues during which no new PET bottles 1 are detected by the object detection sensor, for example, because the conveying line 10 has been stopped or there are no more PET bottles 1 passing in front of the projection lens 24 on the conveying line 10.

[0049] <3. Example of the configuration of objects and marked products> 5 to 9 are diagrams showing an example of an object to be laser marked and a structure of a marked product produced by applying laser marking to the object. The objects are PET bottles 11A to 11E having transparent resin container bodies 114A to 114E. The container bodies 114A to 114E include bottoms 110A to 110E, side portions 111A to 111E extending upward from the outer periphery of the bottoms 110A to 110E, shoulder portions 112A to 112E, and mouth portions 113A to 113E. The mouth portions 113A to 113E define an upper opening. The shoulder portions 112A to 112E are continuous with the upper ends of the side portions 111A to 111E and the lower ends of the mouth portions 113A to 113E, and form an inclined surface inclined with respect to the vertical direction or a curved surface.

[0050] As shown in FIG. 5, a recess 115A is formed on the side surface 111A of the PET bottle 11A, extending along its entire circumference. The recess 115A is a portion of the side surface 111A that is recessed toward the inside of the container body 114A relative to other portions. In other words, the side surface 111A defines the periphery 1151A, 1152A and the bottom surface 1150A of the recess 115A. The bottom surface 1150A is located at the innermost position on the inner surface of the recess 115A and faces the external space of the container body 114A. For example, when the bottom surface 1150A of the recess 115A of the PET bottle 11A is laser marked by the above-mentioned method for producing a marked product, a PET bottle 1A is obtained as a marked product in which a marking area M is formed on the bottom surface 1150A. In this case, in the above-mentioned method for producing a marked product, irradiating the PET bottle 11A during transportation with a laser beam includes irradiating the bottom surface 1150A with a laser beam. The marking area M includes a collection of multiple recesses or a collection of multiple protrusions formed by laser marks, and displays a predetermined design. The minimum depth of the recesses 115A (the distance from the rim 1151A or rim 1152A to the bottom surface 1150A) is not particularly limited, and may be any depth such that the protrusions of the marking area M do not reach the rims 1151A and 1152A.

[0051] As shown in FIG. 6, a recess 115B is formed on the side surface 111B of the PET bottle 11B, extending from the outer peripheral edge of the bottom surface 110B to the upper end of the side surface 111B (the boundary with the shoulder portion 112B). The recess 115B is a portion of the side surface 111B that is recessed more inwardly into the container body 114B than other portions. In other words, the side surface 111B defines the peripheries 1151B, 1152B and the bottom surface 1150B of the recess 115B. The bottom surface 1150B faces the external space of the container body 114B and is the innermost surface of the inner surface of the recess 115B, and is preferably a flat surface. For example, when the bottom surface 1150B of the PET bottle 11B is laser marked by the above-mentioned method for producing a marked product, a PET bottle 1B is obtained as a marked product in which a marking area M is formed on the bottom surface 1150B. In this case, in the above-mentioned method for producing a marked product, irradiating the PET bottle 11B during transportation with a laser beam includes irradiating the bottom surface 1150B with a laser beam. The marking area M includes a collection of multiple recesses or a collection of multiple protrusions formed by laser marks, and displays a predetermined design. The minimum depth of the recesses 115B (the distance from the rim 1151B or rim 1152B to the bottom surface 1150B) is not particularly limited, and may be any depth such that the protrusions of the marking area M do not reach the rims 1151B and 1152B.

[0052] As shown in FIG. 7, a recess 115C is formed on the side surface 111C of the PET bottle 11C. The recess 115C is a portion of the side surface 111C that is recessed further inwardly into the container body 114C than other portions. In other words, the side surface 111C defines the periphery 1151C of the recess 115C and the bottom surface 1150C. The bottom surface 1150C faces the external space of the container body 114C and is the innermost surface of the inner surface of the recess 115C, and is preferably a flat surface. For example, when the bottom surface 1150C of the PET bottle 11C is laser marked by the above-mentioned method for producing a marked product, a PET bottle 1C is obtained as a marked product in which a marking area M is formed on the bottom surface 1150C. In this case, in the above-mentioned method for producing a marked product, irradiating the PET bottle 11C during transportation with a laser beam includes irradiating the bottom surface 1150C with a laser beam. 7, PET bottle 11C is shown as viewed from the side of recessed portion 115C, and PET bottle 1C is shown as viewed from the front of recessed portion 115C, with recessed portion 115C being rectangular when viewed from the front. Marking area M includes a collection of multiple recesses or multiple protrusions formed by laser marks, and displays a predetermined design. There are no particular limitations on the minimum depth of recessed portion 115C (the distance from periphery 1151C to bottom surface 1150C), and it is sufficient that the protrusions of marking area M do not reach periphery 1151C.

[0053] As shown in FIG. 8, the side surface 111D of the PET bottle 11D is formed with a protruding portion 115D that protrudes from its outer surface. The protruding portion 115D may protrude from the other surrounding portions to the outside of the container body 114D, and its shape is not particularly limited. For example, when laser marking is performed near the protruding portion 115D of the PET bottle 11D by the above-mentioned method for producing a marked product, a PET bottle 1D is obtained as a marked product in which a marking area M is formed near the protruding portion 115D. In this case, in the above-mentioned method for producing a marked product, irradiating the PET bottle 11D during transportation with a laser beam includes irradiating the vicinity of the protruding portion 115D of the PET bottle 11D with a laser beam. Note that in FIG. 8, the PET bottle 11D is shown as viewed from the side of the protruding portion 115D, and the PET bottle 1D is shown as viewed from the front of the protruding portion 115D. The marking area M is formed, for example, below the protruding portion 115D. The maximum height of protrusion 115D based on the outer surface of side surface portion 111D is not particularly limited as long as it protrudes outward beyond the convex portion of marking area M. It is preferable that marking area M is formed as close to the periphery of protrusion 115D as possible.

[0054] As shown in FIG. 9, the side surface 111E of the PET bottle 11E has a plurality of protrusions 115E protruding from its outer surface. The shape of the protrusions 115E is not particularly limited as long as each of them protrudes from the other surrounding parts to the outside of the container body 114D. In FIG. 9, six protrusions 115E are formed and arranged in a substantially rectangular shape, but the number and arrangement of the protrusions 115E are not particularly limited as long as two or more protrusions 115E are formed at regular intervals. For example, when the above-mentioned method for producing a marked product is used to perform laser marking on an area surrounded by the plurality of protrusions 115E of the PET bottle 11E, a PET bottle 1E is obtained as a marked product in which a marking area M is formed in the area surrounded by the plurality of protrusions 115E. In this case, in the above-mentioned method for producing a marked product, irradiating the PET bottle 11E during transportation with a laser beam includes irradiating the area surrounded by the plurality of protrusions 115E of the PET bottle 11E or the area between the two protrusions 115E with a laser beam. The maximum height of each protrusion 115E with respect to the outer surface of the side surface portion 111E as a reference is not particularly limited, and may be any height that protrudes outward beyond the convex portion of the marking region M.

[0055] <4. Features> (1) According to the method for producing a marked product of the above embodiment, the shielding mechanism 22 can form a plurality of laser beams corresponding to a dot pattern formed when the laser light is repeatedly irradiated along a predetermined scanning line. In other words, a desired marking can be applied to one object by irradiating the object with one shot of laser light, so that marking can be easily performed on an object moving at high speed without slowing down the object. As a method for improving the speed of laser marking, a method of installing a plurality of laser oscillators or dividing the laser beam into a plurality of objects and simultaneously marking a plurality of objects can be considered. However, these methods have disadvantages such as a large-scale device and an increased cost, and also have limitations in achieving a marking speed that matches the conveying speed of the object on a general conveying line. In this regard, in the method for producing a marked product of the present embodiment, the irradiation time of one shot is about 10 to 30 nanoseconds, so that it can be easily handled even if the conveying speed of the object is high. Furthermore, when the irradiation time for one shot is within the above range, the distance the object moves during irradiation with laser light can be made sufficiently small relative to the dimensions of the regular uneven shape representing the marking design, thereby avoiding a situation in which the regular uneven shape is not properly formed on the object due to the influence of the conveying speed.

[0056] (2) According to the method for producing a marked product according to the above embodiment, a plurality of laser beams that have passed through the shielding mechanism 22 are shaped into a desired design by the mask member 23. Therefore, by preparing the mask member 23 on which a design pattern corresponding to a desired design is formed, the marking design can be easily changed.

[0057] (3) According to the method for producing a marked product of the above embodiment, multiple laser beams are converged by the projection lens 24, so that marking can be performed according to the size of the object to be marked.

[0058] (4) As described above, the marking area M formed by irradiation with a laser beam has a fine uneven pattern including a set of a plurality of fine recesses or a set of a plurality of fine protrusions formed by removing the material on the surface of the object. The fine uneven pattern is easily broken by contact with other objects. In particular, if the marked product is a PET bottle 1, the uneven pattern may be broken by contact with other objects when distributed in the market, and problems such as the barcode in the marking area M not being correctly read by a barcode reader may occur. However, in the above PET bottles 1A to 1C, since the marking area M is formed on the inner surface of the recessed parts 115A to 115C, it is difficult for the marking area M to come into contact with other objects, and the uneven pattern in the marking area M is difficult to break. Also, in the above PET bottle 1D, since the marking area M is formed near the protruding part 115D, the protruding part 115D prevents the marking area M from coming into contact with other objects, and the uneven pattern in the marking area M is difficult to break. In the above-mentioned PET bottle 1E, the marking area M is formed in an area surrounded by multiple protrusions 115E, which prevents the marking area M from coming into contact with other objects, and the uneven pattern of the marking area M is less likely to be distorted. Therefore, the PET bottles 1A to 1E have the effect of maintaining the visibility of the design displayed in the marking area M and the readability of the information code by a code reader or the like.

[0059] (5) In the case of the PET bottle 11A, the recessed portion 115A extends over the entire circumference. This allows the laser light to be irradiated onto the bottom surface 1150A of the recessed portion 115A, regardless of the rotational position of the PET bottle 11A relative to the laser oscillator 20 during transport on the transport line 10. In addition, in the case of the PET bottles 11B and 11C, the bottom surfaces 1150B and 1150C can be formed as flat surfaces. This allows the focal length difference depending on the position where the laser light is irradiated to be eliminated, regardless of the shape of the side portions 111B and 111C, and allows a more accurate design to be displayed in the marking area M. In the case of the PET bottles 11D and 11E, the transport line 10 is configured to contact the protruding portions 115D and 115E at a predetermined position, so that it can be used as a mechanism for automatically adjusting the rotational position of the PET bottles 11D and 11E before passing through the laser oscillator 20.

[0060] <5. Modifications> Although one embodiment of the present invention has been described above, the present invention is not limited to the above embodiment, and various modifications are possible without departing from the spirit of the present invention. For example, the following modifications are possible. In addition, the gist of the following modifications can be combined as appropriate.

[0061] (1) Each of the field lens 21 and the projection lens 24 may be composed of one lens, or may include multiple lenses.

[0062] (2) The photomask 22A is not limited to the one in which the square-shaped transparent region 221 is formed as in the above embodiment. As another example of the pattern of the photomask 22A formed by the transparent region and the shielding region, for example, the patterns shown in Figs. 10A to 10D can be mentioned. Fig. 10A is an example of a pattern in which a larger square-shaped transparent region 221a and a smaller square-shaped transparent region 221b are combined. Fig. 10B is an example of a pattern in which regular hexagonal transparent regions 221c are regularly arranged. Fig. 10C is an example of a pattern in which a smaller square-shaped transparent region 221d is further arranged between two adjacent transparent regions 221a in the example of Fig. 10A, so that a continuous larger transparent region and a smaller transparent region 221b are formed. Fig. 10D is an example of a pattern in which square-shaped shielding regions 222a and 222b are formed on the inside and outside of a square-shaped transparent region 221e, respectively. It should be noted that any of the configuration examples of the patterns formed by the transmitting regions and the blocking regions described above can be applied not only to the photomask 22A but also to a member in which the blocking region is formed of a high-reflection mirror.

[0063] (3) The mask member 23 is not limited to the one having the slit 231 formed thereon as in the above embodiment. For example, as in the photomask 22A, a chrome film may be laminated in a predetermined pattern on one side of a synthetic quartz substrate to form a shielding region for shielding the laser light and a transmission region for transmitting the laser light. Alternatively, as described in the configuration example of the shielding mechanism 22, the mask member 23 may be formed of a member in which a through hole corresponding to the design pattern 230 is formed in a high reflection mirror, or a transmission hole portion formed of a material that transmits the laser light is formed. The mask member 23 may also be formed of a member in which a high reflection mirror is laminated on one side of a base material that transmits the laser. In this case, the part of the base material on which the high reflection mirror is not laminated corresponds to the design pattern 230. However, the design pattern 230 corresponding to the design of the marking may be formed of the entire transmission region (or the entire slit) that transmits the laser light, or may be formed of the entire shielding region that shields the laser light (or the part where the slit is not formed). When the design pattern 230 is formed in the entire shielding area or in the area where no slits are formed, the unprocessed area on the object surface surrounded by the area where fine irregularities are formed becomes the marking design. From the viewpoint of durability and the possibility of forming the design pattern 230 with a higher degree of freedom, the mask member 23 is preferably one in which a chrome film is laminated on a base material, one in which a high reflection mirror has a through hole formed therein, or one in which a high reflection mirror is laminated on a base material.

[0064] (4) The above-mentioned configuration examples of the shielding mechanism 22 (photomask 22A, a high-reflection mirror with through-holes or transmission holes, and a high-reflection mirror laminated on a base material) and mask member 23 (one with slits 231, one with a chromium film laminated on a base material, one with a high-reflection mirror with through-holes or transmission holes, and one with a high-reflection mirror laminated on a base material) can be freely combined. The shielding mechanism 22 and mask member 23 may be integrally formed as one member. More specifically, a regular pattern of a chromium film laminated on one side of a synthetic quartz substrate may serve both as a pattern for regularly dividing the laser light and as a design pattern. In another example, a regular pattern formed by a high-reflection mirror and through-holes or transmission holes, or a high-reflection mirror and a base material may serve both as a pattern for regularly dividing the laser light and as a design pattern. In other words, the laser light may be divided by a regular path and the laser light may be transmitted according to the design pattern 230 in the same layer. When the shielding mechanism 22 and the mask member 23 are composed of a single member, in the above-mentioned method for producing a marked product, "arranging the shielding mechanism that forms a regular path for the laser light" and "arranging the mask member on which a design pattern is formed" are carried out simultaneously.

[0065] (5) The positional relationship between the shielding mechanism 22 and the mask member 23 is not limited to that described above. For example, the shielding mechanism 22 and the mask member 23 can be arranged with a gap therebetween, or the mask member 23 can be arranged between the projection lens 24 and the conveying line 10 (object). Furthermore, the mask member 23 can be arranged between the laser oscillator 20 and the shielding mechanism 22. However, from the viewpoint of forming the marking design on the object more clearly, it is preferable that the shielding mechanism 22 and the mask member 23 are arranged with as little gap as possible between them, or that they are configured as one unit.

[0066] (6) The shapes of the PET bottle 1, PET bottles 11A-11E, and PET bottles 1A-1E may be changed as appropriate. For example, the side portions 111A-111E may be rectangular tubular, and the shoulder portions 112A-112E may be horizontal. These may be made primarily of thermoplastic resin other than polyethylene terephthalate, and may be opaque or semi-transparent, or may be colored. The recessed portion 115A may be formed in the shoulder portion 112A, not in the side portion 111A. That is, in the PET bottle 1A, the marking area M may be formed in the shoulder portion 112A. The bottom surface 1150A of the recessed portion 115A may be formed as a flat surface. The recessed portion 115B may not extend to the top end of the side portion 111B, and may extend to the shoulder portion 112B. The recessed portion 115B may be formed in the shoulder portion 112A. That is, in the PET bottle 1B, the marking area M may be formed on the shoulder portion 112B. The bottom surface 1150B of the recessed portion 115B may be formed as a curved surface. The recessed portion 115C may be formed on the shoulder portion 112C or the bottom surface portion 110C. That is, in the PET bottle 1C, the marking area M may be formed on the shoulder portion 112C or the bottom surface portion 110C. The bottom surface 1150C of the recessed portion 115C may be formed as a curved surface. The shape of the recessed portion 115C in a front view may also be appropriately changed. In the recessed portions 115A to 111C, the marking area M may be formed on the inner surface, and may not necessarily be formed on the bottom surfaces 1150A to 1150C. The protruding portion 115D may be, for example, an endless ring shape, and the marking area M may be formed within the area surrounded by the protruding portion 115D. Protrusion 115D may be formed on shoulder 112D or bottom 110D. That is, in PET bottle 1D, marking area M may be formed on shoulder 112D or bottom 110D. Protrusion 115E may be formed on shoulder 112E or bottom 110E. That is, in PET bottle 1E, marking area M may be formed on shoulder 112E or bottom 110E. At least two of the recesses 115A-111C, protrusion 115D, and protrusion 115E may be formed on the same resin container.

[0067] (7) The order of steps S1 to S4 in the above flowchart can be changed as appropriate.

[0068] (8) The positional relationship between the conveying line 10 and the marking device 2 can be changed as appropriate. That is, the configuration of the production system is not limited to that of the above embodiment, and can be changed as appropriate. For example, the marking device 2 may be configured to irradiate the object with a laser beam from above or below the conveying line 10. The posture of the object when conveyed by the conveying line 10 is not particularly limited, and for example, in the case of a PET bottle 1, the object can be changed as appropriate, such as conveying the object so that the side of the container body faces upward. The conveying line 10 is not limited to conveying objects by a belt conveyor, and may be conveying objects by buckets or plates (flights), or by a hanging tool. In addition, the object detection sensor described in the above embodiment may be omitted, and the timing of laser beam irradiation and the timing of stopping the irradiation may be controlled by other means. [Explanation of symbols]

[0069] 1, 1A~1E, 11A~11E PET bottles 2. Marking device 10. Conveyor Line 20 Laser Oscillator 21 Field Lens 22 Shielding mechanism 22A Photomask 23 Mask material 24 Projection Lens 220 sides 221, 221a~e transmission area 222, 222a, 222b shielding area 230 Design Patterns 231 Slit

Claims

1. Conveying an object along a conveying path; a shielding mechanism is disposed between a laser oscillator and the transport path, the shielding mechanism forming a regular path of the laser beam by shielding a part of the laser beam generated by the laser oscillator; disposing a mask member between the laser oscillator and the transport path, the mask member having a design pattern formed thereon for transmitting or blocking the laser light in accordance with a design of the marking to be performed on the object; irradiating the object being transported with a laser beam from the laser oscillator; Equipped with How to produce marked products.

2. The laser oscillator may be an excimer laser oscillator, a UV laser oscillator, or a CO 2 A laser oscillator or a YAG laser oscillator. A method for producing the marked product according to claim 1.

3. the shielding mechanism is a photomask having a regular pattern including a shielding region that shields the laser light and a transmission region that transmits the laser light; A method for producing a marked product according to claim 1 or 2.

4. the shielding mechanism is a member having a regular pattern formed thereon, the regular pattern being composed of a shielding region that shields the laser light and a transmitting region that transmits the laser light; The shielding area is formed of a highly reflective mirror. A method for producing a marked product according to claim 1 or 2.

5. the mask member is a photomask on which the design pattern is formed, the design pattern being composed of a blocking region that blocks the laser light and a transmitting region that transmits the laser light; A method for producing a marked product according to claim 1 or 2.

6. the mask member is a member on which the design pattern is formed, the design pattern being composed of a blocking region that blocks the laser light and a transmitting region that transmits the laser light; The shielding area is formed of a highly reflective mirror. A method for producing a marked product according to claim 1 or 2.

7. The shielding mechanism and the mask member are integrally configured. A method for producing a marked product according to claim 1 or 2.

8. The object comprises a resin container body including a bottom surface portion, a side surface portion extending upward from an outer periphery of the bottom surface portion, a mouth portion defining an upper opening, and a shoulder portion continuing to the side surface portion and the mouth portion; At least one of the bottom surface portion, the side surface portion, and the shoulder portion is formed with a recessed portion; Irradiating the object being transported with a laser beam includes irradiating an inner surface of the recess with the laser beam. A method for producing a marked product according to claim 1 or 2.

9. The recess is formed in the side surface portion. A method for producing a marked product according to claim 8.

10. The recessed portion extends around the entire periphery of the side surface. A method for producing a marked product according to claim 9.

11. The recessed portion extends from the outer peripheral edge of the bottom portion to the upper end of the side portion. A method for producing a marked product according to claim 9.

12. The inner surface of the recessed portion forms a flat surface facing an external space of the container body at a deepest position, and irradiating the inner surface of the recessed portion with the laser light includes irradiating the flat surface with the laser light. A method for producing a marked product according to claim 9.

13. The object comprises a resin container body including a bottom surface portion, a side surface portion extending upward from an outer periphery of the bottom surface portion, a mouth portion defining an upper opening, and a shoulder portion continuing to the side surface portion and the mouth portion; At least one of the bottom surface portion, the side surface portion, and the shoulder portion is formed with a protrusion protruding from an outer surface, irradiating the object being transported with a laser beam includes irradiating a vicinity of the protrusion with the laser beam. A method for producing a marked product according to claim 1 or 2.

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