Image forming method, image forming apparatus, and program

Abstract

The objective is to provide an image forming method, an image forming apparatus, and a program that can prevent the phenomenon of images becoming cloudy after washing. [Solution] The present invention provides an image forming method comprising the steps of: dispensing color ink onto a transfer substrate; dispensing white ink, which will serve as a base for the color ink layer, onto the transfer substrate from which the color ink has been dispensed; attaching a powder to the ink layer on which the white ink has been dispensed, which will function as an adhesive for bonding the ink layer to a recording medium; melting the powder to allow it to function as an adhesive; washing the transfer substrate from which the powder has been melted with water; and bonding the recording medium and the transfer substrate after washing with water via the layer of powder that has functioned as an adhesive, and then heating and pressurizing them.

Description

Technical Field

[0001] The present invention relates to an image forming method, an image forming apparatus, and a program.

Background Art

[0002] Conventionally, there is a printing method in an image forming apparatus that uses hot melt resin powder (powder) for printing. This printing method is also called the DTF (Direct to Film) method in the textile field, and performs transfer printing using a hot melt layer (powder layer) formed of resin powder (powder) (for example, Patent Document 1).

Summary of the Invention

Problems to be Solved by the Invention

[0003] However, an image printed by the DTF method on a recording medium is required to have durability against washing. When printing by the conventional DTF method, there is a problem that the image becomes cloudy after washing and drying sufficiently, and the color of the original image changes significantly.

[0004] The present invention has been made in view of the above, and an object thereof is to provide an image forming method, an image forming apparatus, and a program capable of preventing the phenomenon that the image becomes cloudy after washing.

Means for Solving the Problems

[0005] To solve the above-mentioned problems and achieve the objective, the present invention provides an image forming method comprising the steps of: dispensing color ink onto a transfer substrate; dispensing white ink, which will serve as a base for the color ink layer, onto the transfer substrate from which the color ink has been dispensed; attaching a powder to the ink layer on which the white ink has been dispensed, which will function as an adhesive for bonding the ink layer to a recording medium; melting the powder to allow it to function as an adhesive; washing the transfer substrate from which the powder has been melted with water; and bonding the recording medium and the transfer substrate after washing with water via the layer of powder that has functioned as an adhesive, and then heating and pressurizing them. [Effects of the Invention]

[0006] According to the present invention, the phenomenon of images becoming cloudy after washing can be prevented. [Brief explanation of the drawing]

[0007] [Figure 1] Figure 1 shows an example of the steps of the image forming method according to the embodiment. [Figure 2] Figure 2 is an explanatory diagram of the layer configuration in each step of the image formation method. [Figure 3] Figure 3 is a diagram illustrating the mechanism of the clouding phenomenon. [Figure 4] Figure 4 is an explanatory diagram illustrating the mechanism by which the image formation method suppresses the opacification phenomenon. [Figure 5] Figure 5 shows the method used in the verification experiment. [Figure 6] Figure 6 is a table summarizing an example of the results of a verification experiment. [Figure 7] Figure 7 shows an example of the configuration of a DTF printing system, illustrating an example of the system configuration of an image forming apparatus. [Figure 8] Figure 8 is an explanatory diagram of the various parts of the DTF printing system shown in Figure 7. [Figure 9] Figure 9 shows an example of a second system configuration. [Figure 10] Figure 10 shows an example of a third system configuration. [Figure 11] Figure 11 shows an example of a fourth system configuration. [Figure 12] Figure 12 shows an example of the hardware configuration of a control device. [Modes for carrying out the invention]

[0008] Hereinafter, embodiments of the image forming method, image forming apparatus, and program according to the present invention will be described in detail with reference to the attached drawings.

[0009] (Embodiment) The inventor noticed that images printed on recording media such as fabrics and clothing using the Direct to Film (DTF) method appeared to become cloudy after washing. Through experiments, the inventor found that removing the high-boiling point solvent contained in the ink before heat-pressing the ink was effective in suppressing this clouding. The following describes an image forming method, image forming apparatus, and program that apply one of the best methods discovered through experiments. The following includes, where appropriate, the inventor's experimental results and the inventor's predicted mechanism of clouding.

[0010] Figure 1 is a diagram showing an example of the steps of the image forming method according to the embodiment. Figure 2 is an explanatory diagram of the layer configuration in each step of the image forming method according to the embodiment. The steps of the image forming method shown in Figure 1 will be explained with reference to the layer configuration shown in Figure 2 as appropriate.

[0011] First, the image forming apparatus prints color ink onto a film (step S1). The film is a "transfer substrate" that transfers the image to the recording medium. In this embodiment, as an example, a transfer substrate is used in which a release layer 1-2 is provided on a film substrate 1-1, as shown in Figure 2(a). In this embodiment, the layers that are integrally formed on the transfer substrate side in each step are also referred to as the transfer film.

[0012] Subsequent to step S1, the image forming apparatus performs printing with white ink on the film printed with color ink (step S2). The white ink is printed as a color base after the image is transferred to the recording medium.

[0013] Thereby, as shown in (b) of FIG. 2, an ink layer 2-1 corresponding to the image printed in the order of color ink to white ink is formed on the transfer film 1.

[0014] Subsequently, the image forming apparatus applies powder to the ink layer 2-1 of the transfer film 2 after the process of step S2 (step S3). The powder is used for the adhesion between the recording medium 4-1 and the ink layer 2-1. By applying the powder, a powder layer 3-1 is formed on the ink layer 2-1 as shown in (c) of FIG. 2, and the powder functions as an adhesive by melting.

[0015] Subsequently, the image forming apparatus melts the powder (powder layer 3-1) of the transfer film 3 after the process of step S3 (step S4). By melting the powder, the powder layer 3-1 functions as an adhesive.

[0016] Furthermore, after melting the powder (powder layer 3-1), the image forming apparatus washes the film 3 with water in the state of the film (step S5). In this step, the high-boiling solvent contained in the ink is removed by washing with water. The washing with water in the state of the film can be performed, for example, by immersing the film in a water tank. In addition to this, it can also be performed by spraying water on the film with a spray or an inkjet head.

[0017] Then, the image forming apparatus transfers the image to the recording medium 4-1 shown as a T-shirt as an example in (d) of FIG. 2 (step S6). Specifically, while bonding the surface on which the powder layer 3-1 of the transfer film 3 shown in (c) of FIG. 2 is formed to the recording medium 4-1 as shown in (d) of FIG. 2, heating and pressing are performed by the hot plate 1000 of the heat press machine to transfer the image to the recording medium 4-1.

[0018] (e) in FIG. 2 is a step of peeling the film base material 1-1 after the heat press by the heat press machine. Due to the release layer 1-2, the film base material 1-1 can be peeled off neatly along the release layer 1-2.

[0019] (f) in FIG. 2 is a view showing the structure 4 of the image layer including the recording medium 4-1 after the film base material 1-1 is peeled off. As shown in (f) in FIG. 2, on the recording medium 4-1, the powder layer 3-1, the ink layer 2-1, and the release layer 1-2 remain, and the transfer of the image to the recording medium 4-1 is completed.

[0020] Also, in order to improve the durability against peeling by washing and friction, etc., additional heating and pressing may be performed on the structure 4 after the film base material 1-1 is peeled off by a heat press machine. The finish press in step S7 is an additional heat press step performed on the structure 4 after the film base material 1-1 is peeled off. Since heating and pressing are performed without the film base material 1-1 such as thick and hard PET, heat is efficiently transmitted inside, and the powder layer 3-1 can bite well into the fibers of the T-shirt of the recording medium 4-1, so that peeling and color fading by washing can be suppressed. In addition, in order to prevent sticking to the hot plate 1000 of the heat press machine, in the finish press in step S7, a release paper such as cooking paper may be sandwiched between the hot plate 1000 and heat pressed.

[0021] Next, referring to FIGS. 3 and 4, the clouding phenomenon in the image after washing will be described. FIG. 3 is a view for explaining the mechanism of the clouding phenomenon. FIG. 4 is an explanatory view of the mechanism by which the clouding phenomenon is suppressed by the image forming method according to the embodiment.

[0022] First, the mechanism of the image clouding phenomenon will be explained with reference to Figure 3. Figures 3(a) to 3(c) schematically show the changes in the state of the release layer and ink layer on the recording medium 4-1 after the transfer of the image to the recording medium 4-1 is completed in a conventional DTF printing process. Of these, Figure 3(a) shows the state near the interface between the release layer and the ink layer immediately after the end of the DTF printing process, that is, immediately after the transfer is completed; Figure 3(b) shows the state near the interface during washing; and Figure 3(c) shows the state near the interface after the laundry has dried. In all of these figures, the recording medium 4-1 after image transfer in a conventional DTF printing process is represented by the configuration 4, and configuration 4 is the laundry.

[0023] As shown in Figure 3(a), immediately after the completion of the conventional DTF printing process, the high-boiling point solvent A1 contained in the ink has entered from inside the ink layer 2-1 to the interface T1 between the ink layer 2-1 and the release layer 1-2, or into the release layer 1-2 itself. High-boiling point solvents are, for example, high-boiling point solvents such as glycerin and ethylene glycol that are included in the ink to improve the ejection reliability when ejecting ink with an inkjet head.

[0024] The high-boiling-point solvents contained in the ink can be difficult to remove through heating alone, as they can be affected by limitations in temperature settings, such as the performance of the heat press or heater, and by uneven drying.

[0025] Solvents such as glycerin and ethylene glycol are readily soluble in water. Therefore, as shown in Figure 3(b), solvent A1 is easily washed away and removed by water 31 during washing. After solvent A1 is removed, the space where solvent A1 was located is replaced with water A2, as shown in Figure 3(b).

[0026] Then, as shown in Figure 3(c), after the moisture from the laundry evaporates, the water A2 also evaporates, creating empty spaces A3 inside the release layer 1-2 and at the interface T1 between the release layer 1-2 and the ink layer 2-1. The presence of these spaces A3 causes light to scatter, making the image appear cloudy. This is the mechanism of the clouding phenomenon.

[0027] Next, the mechanism by which the opacification phenomenon is suppressed by applying the image forming method according to this embodiment will be explained with reference to Figure 4. In particular, the effects resulting from including the "step of washing the film with water" in step S5 will be explained in detail.

[0028] Figure 4(a) shows the state near the interface T1 between the release layer 1-2 and the ink layer 2-1 immediately after the end of step S4, that is, immediately after the powder layer 3-1 of the transfer film 3 has been melted. Figure 4(b) shows the state near the interface T1 between the release layer 1-2 and the ink layer 2-1 during the "washing with water in the film state" step S5. Note that both Figure 4(a) and Figure 4(b) show the configuration of the film before transfer to the recording medium 4-1, and are therefore shown upside down compared to the configurations in Figures 3(a) to 3(c) and the configurations in Figures 4(c) to 4(e) described later, resulting in a reversed layer arrangement.

[0029] Figures 4(c) to 4(e) correspond to the process from the start of image transfer to the recording medium 4-1 to the completion of peeling off the release layer 1-2. Of these, Figure 4(c) shows the state near the interface T1 between the release layer 1-2 and the ink layer 2-1 immediately after the start of transfer in step S6, that is, immediately after heating and pressurizing by the hot plate 1000 of the heat press machine is started. Figure 4(d) shows the state near the interface T1 between the release layer 1-2 and the ink layer 2-1 after sufficient transfer time has elapsed in step S6. Figure 4(e) shows the state near the interface T1 between the release layer 1-2 and the ink layer 2-1 after the film substrate 1-1 has been peeled off.

[0030] As shown in Figure 4(a), immediately after melting the powder layer 3-1, the high-boiling-point solvent A1 contained in the ink has entered from inside the ink layer 2-1 to the interface T1 between the ink layer 2-1 and the release layer 1-2, or into the release layer 1-2 itself.

[0031] As shown in Figure 4(b), after washing with water in the film state, the high-boiling point solvent A1 is washed away and removed by water 31, and the space where solvent A1 was located is filled with water A2.

[0032] As shown in Figure 4(c), the heat press method, which applies heat and pressure, causes the moisture contained in the interface T1 between the ink layer 2-1 and the release layer 1-2, as well as inside the release layer 1-2, to evaporate. As a result, a space A3 is created at the interface T1 between the ink layer 2-1 and the release layer 1-2, and inside the release layer 1-2.

[0033] As shown in Figure 4(d), after sufficient time has passed since applying pressure, the interface T1 between the ink layer 2-1 and the release layer 1-2, as well as the space A3 that existed inside the release layer 1-2, are crushed and disappear.

[0034] Therefore, as shown in Figure 4(e), after the film substrate 1-1 is peeled off, the solvent A1 and the space at the interface T1 between the ink layer 2-1 and the release layer 1-2, which were the cause of the whitening phenomenon after washing, are eliminated, and the whitening after washing does not occur.

[0035] Next, we will explain the results of the verification experiment conducted using the image forming method according to the embodiment.

[0036] Figure 5 shows the method of the verification experiment. As shown in Figure 5, the water washing in step S5 (see Figure 1) of the image forming method according to the embodiment was performed by immersing the transfer film 3 in a water tank containing water 31, and then heat and pressure were applied with a heat press machine to transfer the image from the transfer film 3 to the recording medium 4-1, and a verification experiment was performed on the configuration 4 on the recording medium 4-1 side after image transfer.

[0037] Figure 6 is a table summarizing an example of the verification experiment results. The table in Figure 6 shows side by side a comparative example of images before washing and after one wash when using the image forming method according to the embodiment (first result) and a comparative example of images before washing and after one wash when using the conventional DTF printing process (results of the conventional process). The image is the image of component 4 on the recording medium 4-1 side after image transfer. The table in Figure 6 also shows the difference ΔE (after washing - before washing) of the color values ​​measured from the pre-wash and post-wash images, which were obtained by measuring the predetermined colors of the pre-wash and post-wash images at this time.

[0038] The results from the conventional process showed that the entire image became cloudy after one wash. Figure 6 shows the "conventional DTF printing process" image "after one wash," with the cloudy areas indicated by a gradient. On the other hand, the first result showed that clouding could not be visually confirmed after one wash.

[0039] The color measured in the pre- and post-wash images was black with (R, G, B) = (0, 0, 0). The difference ΔE value between pre- and post-wash images was a large value of 3.55 in the "conventional DTF printing process" and an extremely small value of 0.446 in the "first result," numerically confirming that the image forming method according to the embodiment does not cause clouding after one wash. In other words, it can be said that implementing the image forming method according to the embodiment has the effect of suppressing color changes due to clouding after washing. Thus, the image forming method according to the embodiment demonstrated an improvement effect on the clouding phenomenon.

[0040] As described above, the image forming method of this embodiment makes it possible to prevent the phenomenon of the image becoming cloudy after washing.

[0041] (First system configuration) The image forming process shown in Figure 1 is carried out, for example, by a control device linking multiple processing devices corresponding to each process as a single system. The configuration including the control device and each processing device is arbitrary. The image forming apparatus according to the embodiment may be carried out by appropriately combining the control device and one or more processing devices.

[0042] Figure 7 is a diagram showing an example of the configuration of a DTF printing system, which is an example of the system configuration of an image forming apparatus according to an embodiment. Figure 8 is an explanatory diagram of each part of the DTF printing system 100 shown in Figure 7.

[0043] The DTF printing system 100 shown in Figure 7 includes a printer 10, a powder processing device 20, and a water washing device 30.

[0044] Printer 10 is a printer that prints color ink and white ink onto a transfer film 50. The transfer film 50 is, for example, a film substrate 1-1 shown in Figure 2(a) with a release layer 1-2 provided on it. For example, as shown in Figure 8, printer 10 has ejection means for a color ink head 11 and a white ink head 12. The color ink head 11 ejects color ink onto the transfer film 50 to print, and the white ink head 12 ejects white ink to print the background. Printer 10 prints by ejecting color ink from the color ink head 11 while feeding the film 50 via a transport mechanism, and then prints by ejecting white ink from the white ink head 12.

[0045] The printer 10 may use serial printing, which involves moving the ink head, or other printing methods. Furthermore, it is not limited to inkjet recording. For example, other methods such as electrophotography or thermal transfer may be used.

[0046] The powder processing device 20 applies powder to the printed surface (ink layer) of the film 50 output from the printer 10, and melts the powder to give the powder layer formed by the powder application an adhesive function. For example, as shown in Figure 8, the powder processing device 20 has a powder application mechanism 21 and a powder drying mechanism 22. The powder application mechanism 21 applies powder to the printed surface of the film 50, and the powder layer formed on the printed surface is dried by applying heat with the powder drying mechanism 22. The powder processing device 20 is, for example, a powder shaker. Of course, the powder processing device 20 may employ a method other than the powder application method described above. Any other device that can adhere powder to the printed surface may be used as appropriate.

[0047] The water washing apparatus 30 washes the film 50, which has been melted from the powder processing apparatus 20, with water. For example, as shown in Figure 8, the water washing apparatus 30 has a water tank filled with water 31, and washes the film 50 with the water 31 in the tank before discharging it. However, it is not limited to a water tank. For example, the film 50 may be washed with water using a mechanism equipped with a water sprayer or the like.

[0048] The film 50 is, for example, a long film wound on a roll 41. The long film 50 is fed out of the roll 41 by a transport mechanism such as rollers, and the fed-out long film 50 is transported through the printer 10, powder processing device 20, and water washing device 30, where it is processed in that order. After processing in the water washing device 30, it is wound onto a winding roll 42. The printer 10, powder processing device 20, water washing device 30, and transport mechanism (a transport mechanism including the roll 41 and the winding roll 42) are controlled by a control device via electrical connections.

[0049] After the water washing process, although not shown in the diagram, the film 50 is cut and transferred to a heat press device to transfer the image from the film 50 onto a recording medium 4-1 such as a T-shirt.

[0050] (Second system configuration) Figure 9 shows an example of the second system configuration 101. Figure 9 corresponds to the configuration of the DTF printing system 100 shown in Figure 8, but with the configuration of the water washing treatment device 30 changed to a water spray mechanism.

[0051] As shown in Figure 9, the water washing apparatus 30 has a water spray device 32. The water spray device 32 sprays water 31 onto the film 50 while conveying the film 50 after powder melting. An example of the water spray device 32 is a water spray device. The rest is a repetition of the explanation in Figure 8, so further explanation is omitted.

[0052] (Third system configuration) Figure 10 shows an example of a third system configuration 102. In Figure 10, a drying device 60 is provided after the water washing device 30 in the configuration of the DTF printing system 100 shown in Figure 8, which dries the film 50 while transporting it.

[0053] The drying device 60 heats the water-soaked film 50 with a heater 61 or the like to sufficiently evaporate the moisture, allowing the film 50 to be wound onto the roll 42 without any problems. Note that the drying device 60 is just one example of a drying method. Of course, other drying methods besides a heater may also be used. The rest of the explanation is a repetition of the explanation in Figure 8, so further explanation will be omitted.

[0054] (Fourth system configuration) Figure 11 shows an example of the fourth system configuration 103. Figure 11 shows an example of the configuration in the DTF printing system 100 shown in Figure 8, in which the ultrasonic printing device 62 for ultrasonically cleaning the film is installed in the water tank of the water washing treatment device 30.

[0055] By installing the ultrasonic application device 62 in the water tank, the film vibrates due to ultrasonic waves, allowing for efficient removal of the solvent. Furthermore, the length of the film transport path in the water tank can be shortened, reducing the overall size of the system. Other details are a repetition of the explanation in Figure 8, so further explanation is omitted.

[0056] (program) Alternatively, a predetermined control device may execute a program that comprehensively controls each processing device to carry out the process including the image forming method described above.

[0057] Figure 12 shows an example of the hardware configuration of a control device. The control device shown in Figure 12 includes a CPU (Central Processing Unit) 200, ROM (Read Only Memory) 201, RAM (Random Access Memory) 202, a communication unit 203, a transport unit 204, a printing unit 205, a powder processing unit 206, a water washing unit 207, a heat press unit 208, and the like.

[0058] The CPU 200 executes the program 210 stored in the ROM 201 to control each component.

[0059] ROM201 is the memory that stores program 210.

[0060] RAM202 is the work area for CPU200.

[0061] The communication unit 203 is a communication controller that communicates with the transport unit 204, the printing unit 205, the powder processing unit 206, the water washing processing unit 207, and the heat press unit 208, etc.

[0062] The CPU 200, ROM 201, RAM 202, and communication unit 203 are connected by a bus 220.

[0063] The transport unit 204 is a transport mechanism that controls the transport of the film 50. The print unit 205 is a printing mechanism that controls the printing of color ink and white ink onto the film 50. The powder processing unit 206 is a processing mechanism that controls the application and drying of powder onto the film 50. The water washing processing unit 207 is a processing mechanism that controls the water washing of the film 50. The heat press unit 208 is a press mechanism that heat presses the film 50 onto the recording medium 4-1 by heating and pressurizing.

[0064] The CPU 200 controls each part by executing the program 210 stored in the ROM 201, thereby performing the control function 301 for image formation.

[0065] Program 210 contains instructions for guiding the steps of the image formation method shown in Figure 1. The CPU 200 executes the steps of the image formation method shown in Figure 1 in order by executing the instructions of Program 210.

[0066] The program executed by the image forming apparatus according to this embodiment is provided as a file in an installable or executable format, recorded on a computer-readable recording medium such as a CD-ROM, flexible disk (FD), CD-R, or DVD (Digital Versatile Disk).

[0067] Furthermore, the program executed by the image forming apparatus according to this embodiment may be stored on a computer connected to a network such as the Internet and provided by downloading it via the network. Alternatively, the program executed by the image forming apparatus according to this embodiment may be provided or distributed via a network such as the Internet.

[0068] Furthermore, the program for the image forming apparatus according to this embodiment may be provided pre-installed in a ROM or the like. [Explanation of Symbols]

[0069] 1, 2, 3 Transfer film 1-1 Film substrate 1-2 Delamination layer 2-1 Ink layer 3-1 Powder layer 4-1 Recording media 10 Printers 11 Color Ink Heads 12 White Ink Heads 20 Powder processing equipment 21 Powder coating mechanism 22 Powder drying mechanism 30 Washing equipment 31 water 32 Water spray device 50 Transfer film 60 Drying equipment 61 Heater 62 Ultrasonic application device 100 DTF Printing Systems A1 Solvent A2 water A3 space [Prior art documents] [Patent Documents]

[0070] [Patent Document 1] Japanese Patent Publication No. 2023-087372

Claims

1. A process of dispensing color ink onto a transfer substrate, A step of dispensing white ink, which will serve as the base for the color ink layer, onto the transfer substrate from which the color ink has been dispensed, A step of attaching a powder that functions as an adhesive to bond the ink layer and the recording medium to the ink layer on which the white ink has been ejected, A step of melting the powder in order to make it function as an adhesive, A step of washing the transfer substrate in which the powder has melted with water, A step of bonding the recording medium and the transfer substrate after washing with water via the layer of powder acting as the adhesive, and then heating and pressurizing them, An image forming method including [specific details omitted].

2. The process includes heating and pressurizing the recording medium and the transfer substrate after washing, which are bonded together via the layer of powder acting as an adhesive, after the film substrate has been peeled off the transfer substrate, and then heating and pressurizing again. The image forming method according to claim 1.

3. Dispensing means for dispensing color ink onto a transfer substrate, Dispensing means for dispensing white ink, which will serve as the base for the color ink layer, onto the transfer substrate from which the color ink has been dispensed, A means for attaching a powder to the ink layer on which the white ink has been ejected, which functions as an adhesive for bonding the ink layer to the recording medium, A means for melting the powder in order to make the powder function as an adhesive, A means for washing the transfer substrate in which the powder has melted with water, An image forming apparatus equipped with the following features.

4. The system further includes an ultrasonic application means for washing the transfer substrate with water and cleaning the transfer substrate with ultrasound. The image forming apparatus according to claim 3.

5. The system further includes a drying means for drying the transfer substrate after washing it with water. The image forming apparatus according to claim 3.

6. In the computer of the control device that controls image formation Steps include: dispensing color ink onto a transfer substrate, The steps include: dispensing white ink, which will serve as the base for the color ink layer, onto the transfer substrate from which the color ink has been dispensed; The steps include: attaching a powder to the ink layer from which the white ink has been ejected, which functions as an adhesive to bond the ink layer to the recording medium; A step of melting the powder in order to make it function as an adhesive, The steps include washing the transfer substrate in which the powder has melted with water, The steps include bonding the recording medium and the transfer substrate after washing with water via the layer of powder acting as an adhesive, and then heating and pressurizing them, A program to execute.

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