JP7669802B2 - LIQUID EJECTION APPARATUS, IMAGE FORMING APPARATUS, AND LIQUID EJECTION METHOD - Google Patents

Description

The present invention relates to a liquid ejection device, an image forming device, and a liquid ejection method.

Conventionally, liquid ejection devices are known that apply a resin layer containing a polyvinyl chloride resin containing a plasticizer to a substrate and eject a liquid such as ink to deposit droplets onto the resin layer. Such liquid ejection devices include those that manufacture sheet-shaped wallpaper by forming an image on a substrate using a liquid ejection method.

In addition, a technique has been disclosed for controlling the amount of aggregating agent applied to a substrate such as paper in order to adjust the diameter of droplets ejected onto a resin layer of the aggregating agent or the like in a liquid ejection device (see, for example, Patent Document 1).

However, the physical properties, such as viscosity, of the resin layer applied to the substrate change depending on the surrounding environment, such as temperature and humidity. Therefore, with the technology of Patent Document 1, the state of the droplets applied to the resin layer, such as their spreading, changes depending on the physical properties of the resin layer, which can cause the state of the droplets on the resin layer to be unstable, and the quality of the image, etc., formed on the resin layer to be unstable.

The present invention aims to stabilize the state of droplets applied to a resin layer.

A liquid ejection device according to one embodiment of the present invention includes a transport unit that transports a substrate in a predetermined transport direction, a resin layer application unit that applies a resin layer containing a resin to the substrate, a liquid ejection unit that deposits droplets onto the resin layer by ejecting liquid, an acquisition unit that acquires physical property information of the resin layer, an adjustment unit that adjusts the physical properties of the resin layer based on the results acquired by the acquisition unit, and a control unit that controls the adjustment operation by the adjustment unit , wherein the resin layer application unit has a mixed liquid storage unit that stores a mixed liquid of the resin and a diluent that dilutes the ratio of the resin contained in the resin layer, and the mixed liquid storage unit is installed at the bottom of the mixed liquid storage unit and has a blade member that is rotatable inside the mixed liquid storage unit .

According to the present invention, the state of the droplets applied onto the resin layer can be stabilized.

1 is a diagram illustrating an example of the overall configuration of an image forming apparatus according to an embodiment. 3A to 3C are diagrams illustrating an example of the configuration of a resin layer applying unit and an adjusting unit according to the first embodiment. 4 is a block diagram showing an example of a hardware configuration of a control unit; FIG. 3 is a block diagram showing an example of a functional configuration of a control unit according to the first embodiment; FIG. FIG. 1 shows a droplet on a low viscosity resin layer. FIG. 1 shows a droplet on a highly viscous resin layer. FIG. 2 is a diagram showing nozzle rows of a liquid ejection head. 13A and 13B are diagrams illustrating an example of an adjustment pattern including droplets applied to a resin layer. FIG. 13 is a diagram showing an example of the relationship between droplet diameter and viscosity of a resin layer. FIG. 4 is a flow chart showing an example of the operation of the image forming apparatus according to the first embodiment. FIG. 13 is a diagram illustrating an example of the configuration of an image forming apparatus according to a second embodiment. FIG. 11 is a block diagram showing an example of a functional configuration of a control unit according to a second embodiment. FIG. 11 is a flowchart showing an example of the operation of the image forming apparatus according to the second embodiment.

Below, the embodiments of the invention will be described in detail with reference to the drawings. In each drawing, the same components are given the same reference numerals, and duplicate explanations will be omitted as appropriate.

The embodiments shown below are illustrative of a liquid ejection device and an image forming device for embodying the technical concept of the present invention, and the present invention is not limited to the embodiments shown below. Unless otherwise specified, the dimensions, materials, shapes, relative positions, etc. of the components described below are intended as examples, and are not intended to limit the scope of the present invention. Furthermore, the sizes and positional relationships of the components shown in the drawings may be exaggerated for clarity of explanation.

The following describes an embodiment using a liquid ejection type image forming apparatus as an example. Note that the terms image formation, recording, printing, copying, and printing in the embodiments are all synonymous.

The liquid is not particularly limited as long as it has a viscosity and surface tension that allows it to be discharged from the liquid discharge unit, but it is preferable that the viscosity of the liquid is 30 mPa·s or less at room temperature and pressure, or when heated or cooled. More specifically, the liquid may be a solution, suspension, emulsion, etc. that contains a solvent such as water or an organic solvent, a colorant such as a dye or pigment, a functionalizing material such as a polymerizable compound, a resin, or a surfactant, a biocompatible material such as DNA, amino acids, proteins, or calcium, or an edible material such as a natural dye. These can be used, for example, in applications such as inkjet inks.

The liquid ejection unit is a functional component that ejects and sprays liquid from the nozzle. Energy sources for ejecting liquid include those that use piezoelectric actuators (laminated piezoelectric elements and thin-film piezoelectric elements), thermal actuators that use electrothermal conversion elements such as heating resistors, and electrostatic actuators that consist of a vibration plate and an opposing electrode.

[First embodiment]
(Example of Overall Configuration of Image Forming Apparatus 100)
Fig. 1 is a diagram showing an example of the overall configuration of an image forming apparatus 100 according to an embodiment. As shown in Fig. 1, the image forming apparatus 100 has a resin layer application unit 1, a conveyance unit 2, a liquid ejection unit 3, a reading unit 4, a control unit 5, and an adjustment unit 6.

The image forming apparatus 100 applies a resin layer to the substrate 10 using the resin layer application unit 1, and deposits droplets of liquid ejected by the liquid ejection unit 3 onto the applied resin layer. The image forming apparatus 100 also adjusts the physical properties of the resin layer using the adjustment unit 6 under the control of the control unit 5, based on the results of reading the pattern formed by the droplets deposited on the resin layer using the reading unit 4.

For example, the image forming device 100 can apply droplets onto a resin layer applied to the substrate 10 to form an image, thereby manufacturing the substrate 10 as wallpaper. When manufacturing wallpaper, the material of the substrate 10 is not particularly limited as long as it has suitable mechanical strength, heat resistance, etc., as a substrate for wallpaper, and a substrate commonly used for wallpaper, such as paper or nonwoven fabric, can be used. More specifically, the substrate 10 can be natural paper, plastic film, synthetic paper, nonwoven fabric, cloth, wood, thin metal film, etc., and is selected according to the application.

The resin layer application unit 1 applies a resin-containing resin layer to at least one surface of a smooth substrate 10 made of paper or nonwoven fabric. When producing wallpaper, the resin contained in the resin layer can be vinyl chloride resin, acrylic resin, or the like. The resin layer may contain a plasticizer, or may contain a plasticizer and a heat-foaming agent. The resin layer is applied onto the substrate 10 with at least the vinyl chloride resin containing the plasticizer.

The conveying unit 2 includes a conveying roller 21, a preheat drum 22, and a heating drum 23, and by rotating each of them, conveys the substrate 10 that is wrapped around each of them along a predetermined conveying direction 20. The conveying unit 2 may further include rollers or drums other than these that are used to convey the substrate 10.

The preheat drum 22 and the heating drum 23 are provided downstream of the resin layer application section 1 in the conveying direction 20. Each of the preheat drum 22 and the heating drum 23 has a heater provided therein, and the substrate 10 in contact with the outer peripheral surface of the preheat drum 22 is heated by the heat from the heater while being conveyed.

The preheat drum 22 preheats the substrate 10 on which the resin layer is applied. The heating drum 23 heats the substrate 10 to a substantially constant temperature while transporting the region of the substrate 10 on which the resin layer is applied to the position of the liquid ejection unit 3. The resin heated by the preheat drum 22 and the heating drum 23 gels, thereby fixing the resin layer on the substrate 10.

The preheat drum 22 and the heating drum 23 are not essential components, but from the viewpoint of stably fixing the resin layer to the substrate 10, it is preferable that the image forming apparatus 100 includes a component such as the heating drum 23 that heats the resin layer after application.

The liquid ejection unit 3 is provided downstream of the resin layer application unit 1 in the transport direction 20. The liquid ejection unit 3 ejects liquid onto the resin layer of the substrate 10 that has been applied by the resin layer application unit 1 and then transported by the heating drum 23, thereby applying droplets.

The liquid ejection unit 3 has liquid ejection heads 3A, 3B, 3C, and 3D. The liquid ejection heads 3A, 3B, 3C, and 3D are arranged side by side along the transport direction 20 so that they can eject liquid sequentially toward the substrate 10 being transported.

Liquid ejection heads 3A, 3B, 3C, and 3D may eject liquid of the same color or different colors. For example, liquid ejection heads 3A, 3B, 3C, and 3D can form a full-color image on the resin layer by ejecting cyan, magenta, yellow, and black liquids.

The liquid ejected by the liquid ejection unit 3 is, for example, an oil-based ink that does not have a curing reactivity as a liquid. The oil-based ink contains at least an oil component and a colorant, and may contain a binder resin as necessary. It is preferable that the oil-based ink contains 80% by mass or more of an oil component having a boiling point of 200°C or higher. It is preferable that the oil component of the oil-based ink is mainly composed of ester oil.

The oil-based ink ejected by the liquid ejection unit 3 contains an oil component and a colorant, and from the viewpoint of maintaining good ink fixation after image formation, it is preferable that the ink contains 30% by mass or more of ester oil, and more preferably 50% by mass or more and 90% by mass or less. The oil-based ink may also contain 5% by mass or less of water.

The reading unit 4 is an example of an acquisition unit that acquires physical property information of a resin layer. For example, the reading unit 4 is an in-line sensor in which pixels such as a CCD (Charge Coupled Device) or a CMOS (Complementary Metal Oxide Semiconductor) are arranged in a line.

The reading unit 4 is arranged so that pixels are arranged in a direction substantially perpendicular to the conveying direction 20, and can capture a two-dimensional pattern by reading the pattern on the resin layer of the substrate 10 conveyed along the conveying direction 20. However, the reading unit 4 is not limited to an in-line sensor, and may be configured to include a two-dimensional imaging element in which pixels such as a CCD or CMOS are arranged two-dimensionally.

When measuring the physical properties of the resin layer using the reading unit 4, the image forming apparatus 100 first uses the liquid ejection unit 3 to form a predetermined adjustment pattern (predetermined pattern) on the resin layer in order to obtain physical property information of the resin layer. Then, the reading unit 4, which is provided downstream of the liquid ejection unit 3 in the transport direction 20, reads the pattern formed on the resin layer.

The adjustment pattern is, for example, a dot pattern made of droplets. The physical property of the resin layer to be acquired is, for example, viscosity. Since the spread of the droplets applied to the resin layer differs depending on the viscosity of the resin layer, the reading unit 4 reads an image of the dot pattern made of droplets and outputs the read image to the control unit 5. In the following description, the viscosity of the resin layer is taken as an example of a physical property of the resin layer.

The control unit 5 controls the liquid ejection operation by the liquid ejection unit 3, the transport operation of the substrate 10 by the transport unit 2, and the adjustment operation by the adjustment unit 6 based on the viscosity information of the resin layer.

[First embodiment]
(Example of the configuration of the resin layer application unit 1 and the adjustment unit 6)
FIG. 2 is a diagram showing an example of the configuration of the resin layer applying unit 1 and the adjusting unit 6 according to the first embodiment.

The resin layer application unit 1 has a mixed liquid storage unit 11, an agitation unit 12, an application roller 13, and a blade 14. The resin layer application unit 1 applies a resin layer made of a mixed liquid 15 of a resin and a diluent that dilutes the ratio of the resin contained in the resin layer to the substrate 10.

The mixed liquid storage section 11 is a container that stores the mixed liquid 15. The vertical upper part of the mixed liquid storage section 11 is open to the atmosphere.

The agitator 12 is a blade member that is rotatably provided inside the mixed liquid storage unit 11. The agitator 12 stirs the mixed liquid 15 stored in the mixed liquid storage unit 11 by its own rotation, thereby agitating the mixed liquid 15 so that the ratio of resin to diluent is approximately constant throughout the mixed liquid 15.

The substrate 10 is wrapped around the outer periphery of the application roller 13. The application roller 13 is arranged so that a portion of the wrapped substrate 10 can be immersed in the mixed liquid 15 through the open vertical upper portion of the mixed liquid storage section 11. The mixed liquid 15 adheres to the area of the substrate 10 that is immersed in the mixed liquid 15.

The blade 14 is provided downstream of the immersion area of the substrate 10 in the transport direction 20. The blade 14 abuts its leading edge against the surface of the substrate 10 being transported, thereby regulating the thickness of the mixed liquid 15 attached to the surface of the substrate 10 to be approximately constant. As a result, the mixed liquid 15 is applied to the surface of the substrate 10 with an approximately constant thickness, and a resin layer of the mixed liquid 15 is applied onto the substrate 10.

In addition to the above, the resin layer application unit 1 can also apply other methods to apply the resin layer onto the substrate 10, such as nozzle coating, die coating, lip coating, comma coating, gravure coating, rotary screen coating, and reverse roll coating.

On the other hand, the adjustment unit 6 has a diluent tank 61, a diluent on-off valve 62, a diluent supply nozzle 63, a resin tank 64, a resin on-off valve 65, and a resin supply nozzle 66. The adjustment unit 6 adjusts the physical properties of the resin layer applied to the substrate 10 by supplying at least one of a resin and a diluent to the mixed liquid storage unit 11. Note that any liquid may be used as the diluent as long as it dilutes the physical properties, such as the viscosity, of the mixed liquid 15.

The diluent tank 61 is a container that stores the diluent. One end of the diluent supply nozzle 63 is connected to the diluent tank 61 via a diluent on-off valve 62. The diluent on-off valve 62 is an electromagnetic valve that can be opened and closed in response to a control signal from the control unit 5. The other end of the diluent supply nozzle 63 is connected to the mixed liquid storage unit 11. The diluent tank 61 and the mixed liquid storage unit 11 are in communication with each other via the diluent supply nozzle 63.

The diluent tank 61 is provided so that the liquid level of the stored diluent is higher in the vertical direction than the liquid level of the mixed liquid 15 in the mixed liquid storage section 11. Therefore, when the diluent on-off valve 62 is opened, the diluent in the diluent tank 61 flows toward the mixed liquid storage section 11 due to the hydraulic head pressure, and is supplied to the mixed liquid storage section 11. When the diluent on-off valve 62 is closed, the supply of the diluent to the mixed liquid storage section 11 is stopped.

The resin tank 64 is a container that stores liquid resin. One end of a resin supply nozzle 66 is connected to the resin tank 64 via a resin on-off valve 65. The resin on-off valve 65 is an electromagnetic valve that can be opened and closed in response to a control signal from the control unit 5. The other end of the resin supply nozzle 66 is connected to the mixed liquid storage unit 11. The resin tank 64 and the mixed liquid storage unit 11 are in communication with each other via the resin supply nozzle 66.

The resin tank 64 is arranged so that the liquid level of the stored resin is higher in the vertical direction compared to the liquid level of the mixed liquid 15 in the mixed liquid storage section 11. Therefore, when the resin on-off valve 65 is opened, the resin in the resin tank 64 flows toward the mixed liquid storage section 11 due to the head pressure and is supplied to the mixed liquid storage section 11. When the resin on-off valve 65 is closed, the supply of resin to the mixed liquid storage section 11 is stopped.

When the diluent is supplied, the ratio of the diluent in the mixed liquid 15 in the mixed liquid storage section 11 increases, so the viscosity of the mixed liquid 15 decreases, and the viscosity of the resin layer formed by the mixed liquid 15 decreases. On the other hand, when the resin is supplied, the ratio of the resin in the mixed liquid 15 in the mixed liquid storage section 11 increases, so the viscosity of the mixed liquid 15 increases, and the viscosity of the resin layer formed by the mixed liquid 15 increases. Therefore, the adjustment section 6 can adjust the viscosity of the resin layer by supplying or stopping the supply of at least one of the diluent and the resin to the mixed liquid storage section 11 in response to a control signal from the control section 5.

In this embodiment, a configuration that uses hydraulic head pressure to supply the diluent and resin is illustrated, but this is not limited to this, and a configuration that uses a pump or the like may also be used.

The configuration of the adjustment unit 6 and the method of adjusting the physical properties of the liquid by the adjustment unit 6 are not limited to those described using FIG. 2, and any adjustment method may be used as long as it is possible to adjust the physical properties of the liquid.

(Configuration of control unit 5)
3 is a block diagram showing an example of the hardware configuration of the control unit 5. The control unit 5 has a CPU (Central Processing Unit) 101, a ROM (Read Only Memory) 102, a RAM (Random Access Memory) 103, a HDD (Hard Disk Drive)/SSD (Solid State Drive) 104, and an I/F (Interface) 105. These are electrically connected via a system bus B. In addition, the resin layer application unit 1, the conveying unit 2, the liquid ejection unit 3, the reading unit 4, the adjustment unit 6, etc. are connected to the system bus B.

The CPU 101 is a processor that uses the RAM 103 as a working area and executes the programs stored in the ROM 102. The HDD/SSD 104 is used as a storage unit and stores preset setting values. The CPU 101 may read information stored in the HDD/SSD 104 and use it when executing a program. The I/F 105 is an interface that connects the control unit 5 to an external device 7 such as a client PC (Personal Computer) so that they can communicate with each other.

Figure 4 is a block diagram showing an example of the functional configuration of the control unit 5 according to the first embodiment. The control unit 5 has a resin layer application control unit 51, a transport control unit 52, a discharge control unit 53, a physical property information acquisition unit 54, an adjustment control unit 55, and an input/output unit 56. These functions are realized by the CPU 101 in Figure 3 executing a predetermined program, etc. Note that the control unit 5 may have other functions.

The resin layer application control unit 51 controls the operation of the resin layer application unit 1, the transport control unit 52 controls the operation of the transport unit 2, the ejection control unit 53 controls the operation of the liquid ejection unit 3, and the adjustment control unit 55 controls the operation of the adjustment unit 6.

The physical property information acquisition unit 54 detects the diameter of the droplets contained in the adjustment pattern of the read image by image processing the read image input from the reading unit 4. The physical property information acquisition unit 54 then acquires viscosity information of the resin layer by referring to the correspondence between the droplet diameter and the viscosity of the resin layer that is determined in advance based on the diameter of the droplets, and outputs the physical property information to the adjustment control unit 55. The function of the physical property information acquisition unit 54 may be provided by the reading unit 4.

The adjustment control unit 55 controls the supply of the diluent and resin by the adjustment unit 6 and controls the viscosity adjustment of the resin layer by outputting control signals that control the opening and closing of the diluent on-off valve 62 and the resin on-off valve 65 according to the physical property information of the resin layer input from the physical property information acquisition unit 54.

(An example of a droplet on a resin layer)
Fig. 5 is a diagram showing droplets on a low-viscosity resin layer, showing droplets 31 applied onto a resin layer 30a coated on a substrate 10. Fig. 6 is a diagram showing droplets on a high-viscosity resin layer, showing droplets 31 applied onto a resin layer 30b coated on a substrate 10.

Since the viscosity of the resin layer 30a is higher than that of the resin layer 30b, the wettability (hydrophilicity) of the resin layer 30a is higher than that of the resin layer 30b, and the droplets 31 on the resin layer 30a wet and spread more than the droplets 31 on the resin layer 30b. As a result, the diameter Da of the droplets 31 on the resin layer 30a is larger than the diameter Db of the droplets 31 on the resin layer 30b.

(An example of an adjustment pattern)
7 and 8 are diagrams for explaining an example of an adjustment pattern. Fig. 7 is a diagram showing the nozzle row of the liquid ejection head 3A, and is a plan view of the surface of the liquid ejection head 3A on which the nozzles are provided. Fig. 8 is a diagram showing an example of an adjustment pattern made of droplets 31 applied onto the resin layer 30 by ejection from the liquid ejection head 3A, and is a plan view of the resin layer 30 applied to the substrate 10 from the side on which the droplets 31 are applied.

As shown in FIG. 7, the liquid ejection head 3A is provided with nozzle rows 3Aa to 3Ad. Each of the nozzle rows 3Aa to 3Ad includes a plurality of nozzle holes that eject liquid, and the plurality of nozzle holes are arranged in a direction substantially perpendicular to the transport direction 20. Note that while the liquid ejection head 3A is shown here as an example, all of the liquid ejection heads 3A to 3D in the liquid ejection section 3 have the same configuration, so the liquid ejection head in FIG. 7 may be any of the liquid ejection heads 3A to 3D.

As shown in FIG. 8, the adjustment pattern 32 includes patterns 32a, 32b, 32c, and 32d. Pattern 32a is a pattern made of droplets 31 ejected from nozzle row 3Aa. Pattern 32b is a pattern made of droplets 31 ejected from nozzle row 3Ab. Pattern 32c is a pattern made of droplets 31 ejected from nozzle row 3Ac. Pattern 32d is a pattern made of droplets 31 ejected from nozzle row 3Ad.

The adjustment pattern 32 is a dot pattern applied onto the resin layer 30 at intervals such that the droplets 31 ejected from each nozzle in the nozzle rows 3Aa to 3Ad do not coalesce.

The reading unit 4 reads the adjustment pattern 32 and outputs the read image to the control unit 5. The physical property information acquisition unit 54 of the control unit 5 processes the read image of the adjustment pattern 32 and detects the diameter of the droplet 31 that corresponds to one dot in the read image.

The physical property information acquisition unit 54 may detect only the diameter information of a specific droplet 31 among the multiple droplets 31 included in the adjustment pattern 32, or may detect the average value of the diameter information of the multiple droplets 31 as the diameter information of the droplet 31.

(Example of Correspondence Between Diameter of Droplet 31 and Viscosity of Resin Layer 30)
9 is a diagram showing an example of the correspondence relationship between the diameter of the droplets 31 applied onto the resin layer 30 and the viscosity of the resin layer 30. In Fig. 9, the horizontal axis represents the viscosity of the resin layer 30, and the vertical axis represents the diameter of the droplets 31.

The greater the viscosity of the resin layer 30, the lower the wettability of the resin layer 30, so the droplets 31 applied onto the resin layer 30 spread less and the diameter of the droplets 31 becomes smaller.

The correspondence relationship in FIG. 9 is stored in advance as a correspondence table in the HDD/SSD 104 or the like. The physical property information acquisition unit 54 can acquire viscosity information of the resin layer 30 based on the diameter information of the detected droplet 31 by referring to the correspondence table stored in the HDD/SSD 104.

(Example of Operation of Image Forming Apparatus 100)
Fig. 10 is a flowchart showing an example of the viscosity adjustment operation of the resin layer 30 by the image forming apparatus 100. Fig. 10 shows an operation triggered by the start of viscosity adjustment of the resin layer 30 by the image forming apparatus 100. This trigger may be set to be automatically activated at a predetermined timing, or may be set to be activated in response to an operation input signal to the image forming apparatus 100 by a user of the image forming apparatus 100.

The image forming apparatus 100 can perform the operation of FIG. 10 as appropriate depending on the intended use and environment of the image forming apparatus 100. For example, the image forming apparatus 100 may perform the operation of FIG. 10 every time the image forming apparatus 100 forms an image, or the image forming apparatus 100 may perform the operation of FIG. 10 once at a predetermined timing such as when the image forming apparatus 100 is started.

First, in step S101, the image forming apparatus 100 applies a resin layer 30 onto the substrate 10 using the resin layer application unit 1.

Next, in step S102, the image forming apparatus 100 ejects liquid from the liquid ejection unit 3 while transporting the substrate 10 with the transport unit 2, thereby depositing droplets 31 onto the resin layer 30 applied to the substrate 10, and forming a predetermined adjustment pattern 32 on the resin layer 30. This adjustment pattern 32 is, for example, a dot pattern.

Next, in step S103, the image forming device 100 reads the adjustment pattern 32 formed on the resin layer 30 using the reading unit 4.

Next, in step S104, the image forming device 100 detects the diameter of the droplets 31 contained in the adjustment pattern 32 by subjecting the image of the adjustment pattern 32 read by the reading unit 4 to image processing by the control unit 5.

Next, in step S105, the image forming device 100 determines whether the diameter of the detected droplet 31 is within a target diameter range. This target diameter range is an example of a predetermined diameter range.

If it is determined in step S105 that the diameter is within the target diameter range (step S105, Yes), the image forming device 100 ends the operation. On the other hand, if it is determined that the diameter is not within the target diameter range (step S105, No), in step S106, the image forming device 100 determines whether the diameter of the droplet 31 is smaller than the target diameter range.

If it is determined in step S106 that the diameter is smaller than the target diameter range (step S106, Yes), in step S107, the image forming device 100 reduces the viscosity of the mixed liquid 15 and the viscosity of the resin layer 30 by supplying dilution liquid to the mixed liquid storage section 11 using the adjustment section 6.

On the other hand, if it is determined in step S106 that the diameter is not smaller than the target diameter range (step S106, No), in step S108, the image forming device 100 increases the viscosity of the mixed liquid 15 by supplying resin to the mixed liquid storage section 11 using the adjustment section 6, thereby increasing the viscosity of the resin layer 30.

In this way, the image forming apparatus 100 can adjust the viscosity of the resin layer 30.

<Functions and Effects of Image Forming Apparatus 100>
Next, the effects of the image forming apparatus 100 will be described.

Sheet-type wallpaper with excellent design has traditionally been used for the interior walls and ceilings of buildings. In manufacturing this wallpaper, an image forming device is known that applies a resin layer made of polyvinyl chloride resin containing a plasticizer onto a non-flammable substrate such as base paper or nonwoven fabric, and forms an image on the resin layer using a liquid ejection method.

However, in conventional image forming devices, the wettability of the resin layer changes due to the influence of the temperature, humidity, etc., around the image forming device. If the wettability of the resin layer is high, the droplets on the resin layer spread easily, and if the wettability of the resin layer is low, they do not spread easily. As a result, the coverage rate of the droplets on the substrate differs depending on the temperature, humidity, etc., and the quality of the formed image may vary and become unstable.

As a countermeasure to this problem, the operator of the image forming device can add a diluent to the resin layer while visually checking the quality of the image formed on the substrate, but this increases the number of steps required and can cause problems such as variations in image quality depending on the operator performing the work.

The image forming apparatus 100 according to this embodiment has a conveying section 2 that conveys the substrate 10 in a conveying direction 20, a resin layer application section 1 that applies a resin-containing resin layer 30 to the substrate 10, and a liquid ejection section 3 that applies liquid droplets 31 onto the resin layer 30 by ejecting liquid. The image forming apparatus 100 also has a reading section 4 (acquisition section) that acquires physical property information of the resin layer 30, an adjustment section 6 that adjusts the viscosity (physical property) of the resin layer 30, and a control section 5 that controls the adjustment operation by the adjustment section 6.

For example, the resin layer application unit 1 applies a mixed liquid 15 of resin and a diluent that dilutes the ratio of resin contained in the resin layer to the substrate 10 to apply the resin layer 30, and the mixed liquid 15 is stored in the mixed liquid storage unit 11. The adjustment unit 6 adjusts the viscosity of the resin layer 30 by supplying at least one of the resin and the diluent to the mixed liquid storage unit 11.

The liquid ejection unit 3 forms an adjustment pattern 32 (a predetermined pattern) by applying droplets 31 onto the resin layer 30, and the reading unit 4 obtains viscosity information of the resin layer 30 based on the adjustment pattern 32 formed on the resin layer 30.

With this configuration, even if the viscosity of the resin layer 30 changes due to changes in temperature and humidity around the image forming device 100, the image forming device 100 can adjust the viscosity of the resin layer 30 using the adjustment unit 6 based on the viscosity information of the resin layer 30 obtained from the results of reading the adjustment pattern 32 by the reading unit 4. As a result, the change in viscosity of the resin layer 30 can be suppressed, and the state of the droplets applied onto the resin layer 30 can be stabilized.

In this embodiment, the reading unit 4 obtains viscosity information of the resin layer 30 based on the diameter of the droplets 31 contained in the adjustment pattern 32 formed on the resin layer 30 downstream of the liquid ejection unit 3 in the transport direction 20.

For example, the adjustment unit 6 adjusts the viscosity of the resin layer 30 by supplying resin to the mixed liquid storage unit 11 when the diameter of the droplets 31 is larger than the target diameter range (predetermined diameter range), and by supplying a diluent to the mixed liquid storage unit 11 when the diameter of the droplets 31 is smaller than the target diameter range.

Since viscosity information of the resin layer 30 is obtained from the diameter of the droplets 31 applied onto the resin layer 30 by the liquid ejection unit 3, the viscosity change of the resin layer 30 that affects the state of the droplets 31 can be obtained more accurately. This makes it possible to further suppress the viscosity change of the resin layer 30 and to further stabilize the state of the droplets applied onto the resin layer 30.

In this embodiment, the resin layer 30 contains polyvinyl chloride. This makes it easier to apply the resin layer 30 onto the substrate 10, and also allows the resin layer 30 to have good weather resistance, water resistance, strength, etc.

In this embodiment, the liquid ejected by the liquid ejection unit 3 is oil-based ink. By applying oil-based ink to the resin layer 30 in a heated state to form an image, it is possible to apply liquid with good image quality without the need to provide a special receiving layer.

In this embodiment, the viscosity of the resin layer 30 is exemplified as a physical property of the resin layer 30, but this is not limiting. The image forming apparatus 100 can acquire information on the surface tension and wettability of the resin layer 30, and adjust the surface tension and wettability of the resin layer 30 using the adjustment unit 6 based on the acquired information. In this case, too, it is possible to suppress changes in the surface tension and wettability of the resin layer 30 and stabilize the state of the droplets applied onto the resin layer 30.

In this embodiment, a dot pattern is exemplified as the adjustment pattern 32, and a method of obtaining liquid viscosity information from the diameter of the dots is exemplified, but the present invention is not limited to this. As long as liquid physical property information can be obtained, the adjustment pattern 32 and the information detected from the adjustment pattern 32 can be changed as appropriate depending on the intended use and environment of the image forming apparatus 100.

If the characteristics of the mixed liquid 15 can be monitored using some characteristic value, after adjusting the physical properties based on the diameter of the initial droplets 31, it is also possible to stabilize the image quality by controlling only the characteristic value without detecting the diameter of the droplets 31. Examples of characteristic values include the load on the stirring unit 12 (the higher the viscosity, the greater the load) and the physical properties of the mixed liquid 15. If the physical properties of the mixed liquid 15 are used as the characteristic values, a sensor is required to detect the physical properties of the mixed liquid 15.

[Second embodiment]
Next, an image forming apparatus 100a according to a second embodiment will be described. Note that the same components as those in the first embodiment are denoted by the same reference numerals, and duplicated descriptions will be omitted as appropriate.

Figure 11 is a diagram showing an example of the configuration of an image forming device 100a. As shown in Figure 11, the image forming device 100a has a viscometer 4a and a control unit 5a.

The viscometer 4a is an example of an acquisition unit that acquires viscosity information of the mixed liquid 15 stored in the mixed liquid storage unit 11. There are no particular limitations on the method of measuring the viscosity using the viscometer 4a, and various measurement methods such as a capillary viscometer, a falling ball viscometer, or a rotational viscometer can be used.

The viscometer 4a is immersed in the mixed liquid 15 stored in the mixed liquid storage section 11, and outputs the viscosity measurement results to the control section 5a.

Figure 12 is a block diagram showing an example of the functional configuration of the control unit 5a. As shown in Figure 12, the control unit 5a has a physical property information acquisition unit 54a. The physical property information acquisition unit 54a acquires viscosity information of the resin layer 30 by inputting the viscosity measurement results obtained by the viscometer 4a from the viscometer 4a.

Figure 13 is a flowchart showing an example of the operation of the image forming apparatus 100a. Like Figure 10 described above, Figure 13 is a flowchart showing an example of the viscosity adjustment operation of the resin layer 30 by the image forming apparatus 100a, and shows the operation triggered by the start of viscosity adjustment of the resin layer 30 by the image forming apparatus 100a. Here, the explanation of the parts that overlap with Figure 10 will be omitted, and the explanation will focus on the differences.

First, in step S131, the image forming device 100a uses the viscometer 4a to measure the viscosity of the mixed liquid 15 stored in the mixed liquid storage section 11, and outputs the measurement result to the control section 5a.

Next, in step S132, the image forming device 100a determines whether the measured viscosity of the mixed liquid 15 is within a target viscosity range. This target viscosity range is an example of a predetermined diameter range.

If it is determined in step S132 that the viscosity is within the target viscosity range (step S132, Yes), the image forming device 100a ends the operation. On the other hand, if it is determined that the viscosity is not within the target viscosity range (step S132, No), in step S133, the image forming device 100a determines whether the viscosity is higher than the target viscosity range.

If it is determined in step S133 that the viscosity is higher than the target viscosity range (step S133, Yes), in step S134, the image forming device 100a supplies dilution liquid to the mixed liquid storage section 11 by the adjustment section 6 to reduce the viscosity of the mixed liquid 15, thereby reducing the viscosity of the resin layer 30.

On the other hand, if it is determined in step S133 that the viscosity diameter is not higher than the target viscosity diameter range (step S133, No), in step S135, the image forming device 100a increases the viscosity of the resin layer 30 by supplying resin to the mixed liquid storage section 11 using the adjustment section 6 and increasing the viscosity of the mixed liquid 15.

In this way, the image forming device 100a can adjust the viscosity of the resin layer 30.

<Functions and Effects of Image Forming Apparatus 100a>
As described above, in this embodiment, the viscometer 4a (acquisition unit) acquires viscosity (physical property) information of the mixed liquid 15 stored in the mixed liquid storage unit 11. Even with this configuration, it is possible to obtain the same effects as those described in the first embodiment.

Although the embodiments have been described above, the present invention is not limited to the specifically disclosed embodiments above, and various modifications and variations are possible without departing from the scope of the claims.

In the above-described embodiment, the image forming apparatuses 100 and 100a have been described as examples of liquid ejection apparatuses, but the liquid ejection apparatuses according to the embodiments are not limited to image forming apparatuses. The embodiments can be applied to any apparatus that forms a pattern such as an image on a resin layer applied to a substrate by a liquid ejection method.

The ordinal numbers, quantities, and other numbers used in the description of the embodiments are all given as examples to specifically explain the technology of the present invention, and the present invention is not limited to the exemplified numbers. In addition, the connections between the components are given as examples to specifically explain the technology of the present invention, and the connections that realize the functions of the present invention are not limited to these.

The embodiment also includes a liquid ejection method. For example, the liquid ejection method is a liquid ejection method using a liquid ejection device, in which the liquid ejection device transports a substrate in a predetermined transport direction using a transport unit, applies a resin layer containing resin to the substrate using a resin layer application unit, applies liquid to the substrate using a liquid ejection unit to apply droplets onto the resin layer by ejecting liquid, acquires physical property information of the resin layer using an acquisition unit, adjusts the physical properties of the resin layer using an adjustment unit based on the results acquired by the acquisition unit, and controls the adjustment operation by the adjustment unit using a control unit. With such a liquid ejection method, it is possible to obtain the same effects as the image forming device described above.

Each function of the embodiments described above can be realized by one or more processing circuits. Here, the term "processing circuit" in this specification includes a processor programmed to execute each function by software, such as a processor implemented by an electronic circuit, and devices such as an ASIC (Application Specific Integrated Circuit), DSP (digital signal processor), FPGA (field programmable gate array), and conventional circuit modules designed to execute each function described above.

REFERENCE SIGNS LIST 1 Resin layer application section 11 Mixed liquid storage section 12 Agitation section 13 Application roller 14 Blade 15 Mixed liquid 2 Conveyance section 21 Conveyance roller 22 Preheat drum 23 Heating drum 3 Liquid ejection section 30, 30a, 30b Resin layer 31 Droplet 32 Adjustment pattern (predetermined pattern)
3A, 3B, 3C, 3D Liquid ejection head 4 Reading unit (an example of an acquisition unit)
4a Viscometer (an example of an acquisition unit)
5 Control unit 51 Resin layer application control unit 52 Transport control unit 53 Discharge control unit 54 Physical property information acquisition unit 55 Adjustment control unit 56 Input/output unit 6 Adjustment unit 61 Dilution liquid tank 62 Dilution liquid on-off valve 63 Dilution liquid supply nozzle 64 Resin tank 65 Resin on-off valve 66 Resin supply nozzle 7 External device 10 Substrate 20 Transport direction 100 Image forming device Da, Db Diameter

JP 2010-184479 A

Claims (13)

A conveying unit that conveys the base material in a predetermined conveying direction;
a resin layer applying section that applies a resin layer containing a resin to the base material;
a liquid ejection unit that ejects a liquid to apply droplets onto the resin layer;
An acquisition unit that acquires physical property information of the resin layer;
an adjustment unit that adjusts the physical properties of the resin layer based on the results obtained by the acquisition unit;
A control unit that controls an adjustment operation by the adjustment unit ,
The resin layer application unit has a mixed liquid storage unit that stores a mixed liquid of the resin and a diluent that dilutes the ratio of the resin contained in the resin layer,
The liquid ejection device includes a blade member that is disposed at a bottom of the mixed liquid storage section and is rotatable inside the mixed liquid storage section . the resin layer application unit applies the mixed liquid to the base material to apply the resin layer;
The liquid ejection device according to claim 1 , wherein the adjusting section adjusts the physical properties of the resin layer by supplying at least one of the resin and a diluent to the mixed liquid storage section. the liquid ejection unit forms a predetermined pattern by applying the liquid droplets onto the resin layer;
The liquid ejection apparatus according to claim 1 , wherein the acquisition section acquires physical property information of the resin layer based on the pattern formed in the resin layer. The liquid ejection device according to claim 3, wherein the acquisition unit acquires physical property information of the resin layer based on the diameter of the droplets included in the pattern formed on the resin layer downstream of the liquid ejection unit in the transport direction. the resin layer application unit applies the mixed liquid to the base material to apply the resin layer;
The liquid ejection device according to claim 4, wherein the adjustment section adjusts the physical properties of the resin layer by supplying the resin to the mixed liquid storage section when the diameter of the droplet is larger than a predetermined diameter range, and by supplying the diluent to the mixed liquid storage section when the diameter of the droplet is smaller than a predetermined diameter range. the resin layer application unit applies the mixed liquid to the base material to apply the resin layer;
The liquid ejection device according to claim 1 , wherein the acquisition section acquires physical property information of the mixed liquid stored in the mixed liquid storage section. The liquid ejection device according to any one of claims 1 to 6, wherein the resin layer contains polyvinyl chloride. The liquid ejection device according to any one of claims 1 to 7, wherein the liquid is oil-based ink. The liquid ejection device according to any one of claims 1 to 8, wherein the physical properties of the resin layer include the viscosity of the resin layer. The liquid ejection device according to any one of claims 1 to 9, wherein the physical properties of the resin layer include the surface tension of the resin layer. The liquid ejection device according to any one of claims 1 to 10, wherein the physical properties of the resin layer include the wettability of the resin layer. An image forming apparatus including a liquid ejection device according to any one of claims 1 to 11. A liquid ejection method using a liquid ejection device, the liquid ejection device comprising:
The substrate is transported in a predetermined transport direction by the transport unit;
A resin layer coating unit coats the substrate with a resin layer containing a resin;
A liquid ejection unit ejects liquid to provide droplets onto the resin layer;
An acquisition unit acquires physical property information of the resin layer;
adjusting the physical properties of the resin layer by an adjustment unit based on the results obtained by the acquisition unit;
A control unit controls the adjustment operation by the adjustment unit ;
The resin layer application unit has a mixed liquid storage unit that stores a mixed liquid of the resin and a diluent that dilutes the ratio of the resin contained in the resin layer,
The liquid storage section has a blade member that is disposed at a bottom of the liquid storage section and is rotatable inside the liquid storage section .

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