Liquid dispensing device and liquid dispensing method

Abstract

To provide a liquid discharge device that controls an application quantity of pretreatment liquid so that an expression made using liquid ink can be kept in a satisfactory state, in cloth media, regardless of water repellency.SOLUTION: The liquid discharge device, which discharges liquid to cloth media, comprises: a process liquid application part that applies process liquid for controlling cohesive properties of liquid other than the process liquid on surfaces of the cloth media; a media surface-condition sensing part that senses conditions of the surfaces that vary in accordance with quantities of the process liquid applied to the surfaces of the cloth media; a process liquid quantity determination part that determines whether quantities of the process liquid applied to the surfaces satisfy a predetermined condition or not, on the basis of a sensed result by the media surface-condition sensing part; and a control part that controls motion of the process liquid application part on the basis of a determined result by the process liquid quantity determination part, where the control part controls application quantities of the process liquid by the process liquid application part, in accordance with the determined result by the process liquid quantity determination part.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to a liquid ejection device and a liquid ejection method.

Background Art

[0002] A liquid ejection device that ejects liquid onto a medium based on an image formation instruction from an information processing device or the like is known. The liquid ejection device also functions as an image forming device that forms an image on a medium. And the liquid ejection device is sometimes referred to as an inkjet printer including a liquid ejection head that ejects liquid onto a medium. In recent years, in an inkjet printer, those applicable to fabrics such as clothing (T-shirts) as a medium are known. The inkjet printer is called a "DTG printer (DTG: Direct To Garment)".

[0003] When forming a color image on a fabric as a medium (hereinafter referred to as "fabric medium"), white ink may be used. When the color (background color) of the fabric medium is black or the like, if the white ink adhering to the surface of the fabric medium (media surface) penetrates into the fabric medium, the "whiteness" that should originally be exhibited cannot be fully exhibited, and the white color in the image to be formed will be different from the intended expression, resulting in a deterioration of the image quality. For the purpose of suppressing such a deterioration of the image quality, a technique of performing a pretreatment of applying a chemical that makes white ink likely to aggregate in advance at the location where white ink is ejected onto the fabric medium so that white does not sink into the fabric medium is known. The chemical used in the pretreatment is sometimes referred to as a "pretreatment liquid".

[0004] In addition, for the purpose of preventing the reaction with the liquid ink from becoming non-uniform due to unevenness of the treatment liquid on the media surface and deteriorating the image quality, a technique of adjusting the amount of the liquid repellent applied before the pretreatment liquid based on the parameters of the pretreatment liquid is known (see Patent Document 1).

Summary of the Invention

Problems to be Solved by the Invention

[0005] The technology disclosed in Patent Document 1 controls the water repellency of the media surface, but it is not a technology intended for cloth media. Cloth media have different water repellency on the surface depending on various factors such as the weave, the condition of the fibers, and whether or not post-processing is performed, which results in different degrees of penetration of liquid ink.

[0006] If the water repellency of the surface of a fabric media is higher than a predetermined standard, components of the pretreatment solution will remain on the media surface more easily compared to fabric media with the predetermined standard of water repellency. On the other hand, if the water repellency is lower than a predetermined standard, components of the pretreatment solution will penetrate from the surface into the interior of the media more easily, so components of the pretreatment solution will not remain on the media surface. In other words, if the water repellency is high, if the amount of pretreatment solution is not reduced, the white ink may run off the media surface, resulting in insufficient whiteness. Furthermore, with media with low water repellency, there is a challenge in that sufficient whiteness cannot be achieved unless the amount of pretreatment solution and white ink applied is increased.

[0007] The present invention aims to provide a liquid dispensing device that controls the amount of pretreatment solution applied to a fabric media so that liquid ink expression is in a suitable state, regardless of water repellency. [Means for solving the problem]

[0008] To solve the above technical problems, one embodiment of the present invention is a liquid dispensing device for dispensing liquid onto a cloth media, The background color is black A treatment liquid for controlling the cohesiveness of other liquids on the surface of the cloth media. The processing liquid is transparent or white. A processing liquid application unit that applies the processing liquid to the cloth media, and the surface of the cloth media The brightness and, The aforementioned processing liquid The difference in brightness of the surface to which the coating is applied. A media surface state detection unit that detects the and Brightness difference Based on this, the treatment liquid applied to the surface The water repellency of the surface caused by this A processing liquid volume determination unit that determines the processing liquid volume determination unit The water-repellent properties of the aforementioned surface Based on the judgment result, the processing liquid application section Amount of the processing liquid applied by It comprises a control unit that controls, and the control unit In controlling the amount of coating, when the water repellency of the surface is higher than a predetermined standard, the number of times the treatment solution is applied is reduced, and when the water repellency of the surface is lower than a predetermined standard, the number of times the treatment solution is applied is increased. It is characterized by the following. [Effects of the Invention]

[0009] According to the present invention, regardless of water repellency, the amount of pretreatment solution applied to the fabric media can be controlled so that the expression with liquid ink is in a suitable state. [Brief explanation of the drawing]

[0010] [Figure 1] A schematic plan view showing the main parts of the internal structure of the liquid dispensing device according to the present invention. [Figure 2] A schematic diagram of the control unit according to this embodiment. [Figure 3] Functional block diagram of the control unit according to this embodiment [Figure 4] A flowchart showing the processing flow as an embodiment of the liquid discharge method according to the present invention. [Figure 5] This figure illustrates the relationship between the amount of pretreatment solution applied according to this embodiment and the water-repellent properties of the media surface. [Figure 6] This figure illustrates the relationship between the amount of pretreatment solution applied according to this embodiment and the water-repellent properties of the media surface. [Modes for carrying out the invention]

[0011] [Liquid Dispensing Device Embodiment] The following describes an inkjet printer 100 as an embodiment of the liquid ejection device according to the present invention. The inkjet printer 100 is also a type of image forming device that ejects liquid ink toward a cloth medium to form an image on the surface of the cloth medium.

[0012] The inkjet printer 100 is equipped with an internal pretreatment liquid application unit that has the function of applying a pretreatment liquid to the surface of the fabric media (media surface) to control the coagulation of liquid ink before ejecting liquid ink onto the fabric media.

[0013] The inkjet printer 100 also includes a media surface state detection unit that detects the state of the media surface that changes according to the amount of the pretreatment liquid applied to the media surface.

[0014] Then, the inkjet printer 100 also includes a pretreatment liquid amount determination unit that determines whether or not the amount of the pretreatment liquid applied to the media surface is an appropriate amount under predetermined conditions based on the detection result in the media surface state detection unit.

[0015] Then, the inkjet printer 100 also includes a control unit that comprehensively controls the operations of the pretreatment liquid application unit, the media surface state detection unit, and the pretreatment liquid amount determination unit.

[0016] The control unit controls the detection operation by the media surface state detection unit immediately after the pretreatment liquid is applied to the media surface in the pretreatment liquid application unit. Then, the control unit notifies the pretreatment liquid amount determination unit of the information indicating the state of the media surface detected by the media surface state detection unit. Then, the control unit receives the result determined by the pretreatment amount determination unit based on the information notified to the pretreatment liquid amount determination unit, and notifies the pretreatment liquid application unit of the information for controlling the amount of the pretreatment liquid applied by the pretreatment liquid application unit based on this determination result.

[0017] As described above, the inkjet printer 100 determines whether or not the amount of the pretreatment liquid immediately after being applied to the media surface is an appropriate amount for aggregating the liquid ink, and controls so that an appropriate amount of the pretreatment liquid remains on the media surface according to the determination result.

[0018] According to the inkjet printer 100 having the above configuration, it is possible to apply a suitable pretreatment liquid whether the water repellency of the media surface is higher or lower than a predetermined water repellency performance. As a result, regardless of the water repellency of the media surface, the aggregability of the liquid ink on the media surface can be made in a necessary and sufficient state.

[0019] That is, the inkjet printer 100 controls so that an appropriate amount of pretreatment liquid is present on the media surface before the liquid ink is ejected in order to exhibit suitable water repellency on the media surface. More specifically, it has a function of determining the amount of pretreatment liquid present on the media surface before the ejection of the liquid ink, and determining whether the amount of pretreatment liquid on the media surface is more or less compared with the appropriate amount of pretreatment liquid to exhibit a predetermined water repellency. Then, when the amount of pretreatment liquid is large, the pretreatment liquid application unit is controlled to reduce the application amount of the pretreatment liquid, and when the amount of pretreatment liquid on the media surface is small, the pretreatment liquid application unit is controlled to increase the application amount of the pretreatment liquid more than the predetermined amount.

[0020] Note that the media surface state detection unit has a media surface reading unit for optically reading the media surface immediately after the application of the pretreatment liquid. For example, the media surface reading unit includes an optical sensor that detects the reflected light of the light irradiated toward the target. Based on the brightness difference derivable by the optical sensor detecting the change in the reflected light due to the pretreatment liquid applied to the media surface, the penetration degree (water repellency) of the pretreatment liquid on the media surface is read. Also, for example, the media surface state detection unit includes a line sensor in which CCD sensors for optically reading the media surface are arranged. The line sensor scans the media surface, and based on the difference in brightness between the ground color of the media surface and the brightness of the applied pretreatment liquid, the penetration degree (water repellency) of the pretreatment liquid on the media surface is read. Note that the penetration degree of the pretreatment on the media surface depends on the water repellency of the media surface. Therefore, the media surface detection unit has a function of optically reading the water repellency of the media surface and notifying the information for determination in the pretreatment liquid amount determination unit.

[0021] Note that the media surface state detection unit may be such that the user visually observes the media surface without using the optical sensors as described above, and holds the value input by the user as a set value for controlling the application amount of the pretreatment liquid based on the visual result. And the media surface state detection unit may have a function of notifying the held set value so that it can be determined in the pretreatment liquid amount determination unit.

[0022] As described above, the water-repellency of the media surface is detected, and the amount of pre-treatment solution applied to the media surface is controlled according to the detection result so that the amount of pre-treatment solution applied to the media surface is at a suitable level (state), thereby controlling the aggregation of liquid ink on the media surface to a suitable state. This improves the quality of the image formed on the cloth media.

[0023] [Overview of Inkjet Printer 100] Here, we will describe the hardware configuration of the inkjet printer 100. As shown in Figure 1, the inkjet printer 100 holds the carriage 110 with a slide rail 104 that is integrated with sheet metal. The carriage 110 is scanned by a main scanning motor 105 via a timing belt 102 that is stretched between a drive pulley 106 and a driven pulley 107, moving back and forth in the main scanning direction. In this specification, the main scanning direction refers to the Y direction as shown in Figure 1, etc.

[0024] The carriage 110 is equipped with an ejection head 118 that ejects droplets of various liquids, such as yellow (Y), cyan (C), magenta (M), black (K), white (W), and pre-treatment liquid (S). In this embodiment, an example is shown in which an ejection head 118 is provided corresponding to each liquid, so the liquid ejection head is composed of six ejection heads. The ejection head 118 is mounted with a nozzle row on a nozzle surface that forms multiple ink ejection ports (nozzles) arranged in a direction perpendicular to the main scanning direction (sub-scanning direction), and the ink ejection ports are directed downward (towards the transport platen 101). In this specification, the sub-scanning direction refers to the X direction shown in Figure 1, etc.

[0025] While the example shown for the ejection head 118 mounted on the carriage 110 includes multiple nozzle rows for ejecting ink droplets of each color, this does not limit the configuration of the ejection head 118 applicable to the inkjet printer 100. For example, an ejection head 118 that independently handles ink droplets of each color can also be used. Furthermore, the number of colors applied as ink droplets and the arrangement order of the ejection heads 118 are not limited.

[0026] The discharge head 118 can be equipped with a piezoelectric actuator such as a piezoelectric element, or a thermal actuator that utilizes a phase change due to film boiling of a liquid using an electrothermal conversion element such as a heating resistor, as a pressure generating means to generate pressure for discharging droplets. In addition to these, a shape memory alloy actuator that uses a metal phase change due to temperature change, or an electrostatic actuator that uses electrostatic force can also be used as a pressure generating means. In any configuration, it is sufficient that droplets of a specified color are dispensed in a specified amount at a discharge timing instructed from the outside.

[0027] Furthermore, the carriage 110 is equipped with optical sensors 151 near both ends in the main scanning direction to form a pretreatment liquid determination unit. As the discharge head 118 moves in the main scanning direction while discharging the pretreatment liquid, the optical sensors 151 detect the state of the media surface immediately after application of the pretreatment liquid and notify the control unit 10, which will be described later. This makes it possible to determine the water repellency of the media surface as the carriage 110 moves.

[0028] The inkjet printer 100 is equipped with an encoder scale 103 with slits formed therein, aligned with the main scanning direction. The carriage 110 is equipped with an encoder sensor 117 that detects the slits of the encoder scale 103. Together, these constitute a linear encoder 131 for detecting the position of the carriage 110 in the main scanning direction.

[0029] Furthermore, the inkjet printer 100 is equipped with a transport platen 101 as a media holding member for holding the recording medium 108. The transport platen 101 is moved back and forth in the sub-scanning direction by the transport mechanism while holding the recording medium 108. At this time, the transport platen 101 moves the recording medium 108 back and forth at a position facing the ejection head 118.

[0030] The recording medium 108 can be of any type as long as it is held and transported by the transport platen 101. Therefore, for example, it can be a cloth medium such as clothing.

[0031] The transport platen 101 is configured to move in the sub-scanning direction (X direction) using the sub-scanning motor 111, which constitutes the transport mechanism, as the driving source. A timing belt 114 is stretched between a transport drive pulley 112, which is located on the rotation axis of the sub-scanning motor 111, and a transport roller pulley 113, which is located at a position separated from it. A transport roller 109 is connected to the rotation axis of the transport roller pulley 113. With this configuration, when the sub-scanning motor 111 is rotated, the driving force rotates the transport roller 109, thereby moving the transport platen 101.

[0032] Furthermore, the inkjet printer 100 is equipped with an encoder wheel 115 having a slit formed on it, coaxially with the transport roller 109. An encoder sensor 116 is provided to detect the slit in the encoder wheel 115. The encoder sensor 116 is not shown in Figure 1, but it is provided on a part of the side panel that makes up the housing of the inkjet printer 100. These configurations constitute a wheel encoder 132 for detecting the sub-scanning position of the transport platen 101.

[0033] The transport platen 101 is a flatbed type and is transported horizontally in the sub-scanning direction via a timing belt 119 stretched between the transport roller and the tension roller.

[0034] Furthermore, the inkjet printer 100 is equipped with a line sensor 152 at a position that the cloth media, while placed on the transport platen 101, crosses when it moves in the sub-scanning direction. The line sensor 152 detects the state of the media surface immediately after the application of the pre-treatment liquid when the media, immediately after the pre-treatment liquid has been ejected from the ejection head 118, moves in the sub-scanning direction by the transport platen 101, and notifies the control unit 10, which will be described later. This makes it possible to determine the water-repellency of the media surface along with the movement of the carriage 110.

[0035] Alternatively, similar to the arrangement of the line sensors 152, the dispensing heads for applying the pretreatment liquid may be arranged in the main scanning direction, and the pretreatment liquid may be dispensed and applied from the dispensing heads while scanning the cloth media in the sub-scanning direction, with the surface of the media immediately afterward being detected by the line sensors 152.

[0036] Figure 1 shows an example in which the inkjet printer 100 is equipped with an optical sensor 151 and a line sensor 152, but it may also be equipped with only one of these.

[0037] [Control Block Configuration] Next, the configuration of the control block of the inkjet printer 100 according to this embodiment will be described with reference to Figure 2. As shown in Figure 2, the control block 120 of the inkjet printer 100 includes a CPU 121, ROM 122, RAM 123, NVRAM 124, and ASIC 125.

[0038] The CPU 121 is connected to the control panel 150, which serves as a display and operation unit for inputting and displaying information necessary for the inkjet printer 100, and controls the operation of each functional component of the inkjet printer 100. The CPU 121 also has functions to control the transport operation of the transport platen 101 (movement in the sub-scanning direction), the movement of the carriage 110 in the main scanning direction, and the liquid ejection operation of the ejection head 118.

[0039] Furthermore, the CPU 121 determines the appropriateness of the amount of pretreatment solution applied based on the detection results of the optical sensor 151 and the line sensor 152, and controls the operation of the discharge head 118 that dispenses the pretreatment solution based on the determination result. This control allows for the application of a suitable amount of pretreatment solution according to the water repellency of the surface of the cloth media detected by the optical sensor 151 and the line sensor 152. As a result, the coagulation of the liquid ink can be controlled so that the color development state of the color expressed using the liquid ink is in a suitable state.

[0040] ROM122 is a non-volatile storage medium that stores programs executed by the CPU121 and other fixed data. The control unit 10, which will be described later, is configured by executing the programs stored in ROM122 using the arithmetic processing functions of the CPU121.

[0041] RAM123 temporarily stores image data and other data used in image formation processing. RAM123 also functions as a work area when the program control unit is executed.

[0042] NVRAM124 is a rewritable, non-volatile storage medium for retaining data even when the inkjet printer 100 is powered off.

[0043] The ASIC125 processes image data, including various signal processing and sorting operations, as well as input and output signals for controlling the entire device.

[0044] Furthermore, the control block 120 includes a host interface (I / F) 133, a discharge control unit 127, a main scanning motor drive unit 128, a sensor drive unit 129, a sub-scanning motor drive unit 130, and an input / output (I / O) unit 126.

[0045] The host I / F 133 is responsible for sending and receiving data and control signals to and from the host side, such as the printer driver 501 of the external device 500.

[0046] The discharge control unit 127 generates a drive waveform for driving the discharge head 118 and outputs image data and various associated data to the head driver 141 to selectively drive the pressure generating means of the discharge head 118.

[0047] The main scanning motor drive unit 128 drives the main scanning motor 105.

[0048] The sensor drive unit 129 controls the operation of the optical sensor 151 and the line sensor 152. It receives the detection signals detected by the optical sensor 151 and the line sensor 152 and passes them to a functional block realized by information processing performed in the CPU 121 or the like.

[0049] The sub-scanning motor drive unit 130 is responsible for driving the sub-scanning motor 111, which moves the cassette 200 in the sub-scanning direction.

[0050] The I / O unit 126 receives detection signals from various sensors required for the operation of the inkjet printer 100.

[0051] In the control block 120, image formation instructions related to image formation processing are received via cable or network through the host I / F 133 from the printer driver 501 of the external device 500. The image formation instructions are generated by the printer driver 501 of the external device 500, which has host functionality for information processing devices such as personal computers (PCs), image reading devices such as image scanners, and imaging devices such as digital cameras.

[0052] Upon receiving the image formation instruction, the control block 120, via the CPU 121, reads and analyzes the instruction from the receive buffer included in the host I / F 133. Based on the analysis results, the ASIC 125 performs necessary image processing, data rearrangement, etc., and then transfers the results to the ejection control unit 127. The ejection control unit 127 then outputs image data and drive waveforms to the head driver 141 at the required timing. The generation of dot pattern data for image output can be done, for example, by storing font data in the ROM 122, or by having the host-side printer driver 501 expand the image data into bitmap data and transfer it to the device. Here, for example, this is done by the printer driver 501. Thus, the image formation instruction corresponds to the ejection instruction information.

[0053] The drive waveform generation unit of the ejection control unit 127 consists of a D / A converter and amplifier, etc., which perform D / A conversion on the pattern data of the drive pulses stored in the ROM 122 and read out by the CPU 121. It then outputs a drive waveform consisting of one or more drive pulses to the head driver 141. The head driver 141 drives the ejection head 118 based on image data (dot pattern data) corresponding to one line of the ejection head 118, which is input serially. To this end, the head driver 141 selectively applies the drive pulses that constitute the drive waveform provided by the drive waveform generation unit of the ejection control unit 127 to the pressure generating means of the ejection head 118.

[0054] The head driver 141 includes, for example, a shift register for inputting serial data such as a clock signal and image data, and a latch circuit for latching the register value of the shift register with a latch signal. It also includes a level conversion circuit (level shifter) that changes the level of the output value of the latch circuit, and an analog switch array (switching means) whose on / off state is controlled by this level shifter. Functionally, an example can be given where the required drive pulses included in the drive waveform are selectively applied to the pressure generating means of the discharge head 118 by controlling the on / off state of the analog switch array.

[0055] The image forming instructions include, for example, information indicating the type of cloth media. In the inkjet printer 100 according to this embodiment, a predetermined amount of pretreatment liquid can be selected according to the type of cloth media placed on the transport platen 101. The state of the cloth media surface immediately after the application of the predetermined pretreatment liquid is detected by an optical sensor 151 and a line sensor 152, and the amount of pretreatment liquid applied is controlled based on this detection result.

[0056] [Description of the control unit 10] Next, the functional configuration of the control unit 10 that controls the inkjet printer 100 will be explained using Figure 3. The control unit 10 includes an image forming processing unit 11, a liquid ejection control unit 12, a head movement control unit 13, a platen movement control unit 14, a media reading unit 15 as a media surface state detection unit, and a liquid volume determination unit 16 as a pre-treatment liquid volume determination unit.

[0057] The image forming processing unit 11 generates image data for image formation based on an image forming instruction from the external device 500, and instructs the liquid discharge control unit 12, the head movement control unit 13, and the platen movement control unit 14 to form an image on the fabric using the image data. The image forming processing processing unit 11 also instructs the liquid discharge control unit 12, the head movement control unit 13, and the platen movement control unit 14 to perform a re-image formation process based on an instruction from the re-image formation instruction receiving unit 17.

[0058] Furthermore, the image forming processing unit 11 generates instructions to control the operation of the discharge head 118 that discharges (applies) the processing liquid to the media surface, based on data indicating an increase or decrease in the amount of pre-treatment liquid applied, which is notified by the liquid volume determination unit 16. In other words, the image forming processing unit 11 also functions as a pre-treatment liquid application unit in this embodiment. The instructions correspond to the number of times the pre-treatment liquid is discharged (applied). However, as long as a predetermined amount of processing liquid can be present on the media surface, the control is not limited to the number of times; for example, it may also be possible to control the amount of pre-treatment liquid discharged in a single discharge process.

[0059] The liquid ejection control unit 12 drives the ejection control unit 127 based on instructions from the image forming processing unit 11 to eject liquid (ink) from the ejection head 118 via the head driver 141 at a predetermined timing and in a predetermined amount.

[0060] Based on instructions from the image forming processing unit 11, the head movement control unit 13 drives the main scanning motor 105 to the main scanning motor drive unit 128 to move the carriage 110 in the main scanning direction.

[0061] Based on instructions from the image forming processing unit 11, the platen movement control unit 14 drives the sub-scanning motor 111 to the sub-scanning motor drive unit 130 to move the stage 400 in the sub-scanning direction, thereby performing sub-scanning movement of the fabric held by the platen member 300.

[0062] The media reading unit 15 includes a media surface reading unit 15a that detects the application status of the pretreatment liquid applied to the media surface, which provides the cohesive properties of the liquid ink, based on the state of the media surface detected by the optical sensor 151 and the line sensor 152. The media reading unit 15 also includes a media surface state setting unit 15b that stores information regarding the water repellency of the media surface, which is set by the user via the operation panel 150.

[0063] The liquid volume determination unit 16 determines whether the amount of pretreatment liquid on the media surface is more or less than the appropriate amount, based on the detection results from the media surface reading unit 15a and the setting values ​​held in the media surface state setting unit 15b. It then notifies the image forming processing unit 11 of an instruction based on the determination result.

[0064] In other words, if the amount of pretreatment liquid on the media surface is greater than the amount of pretreatment liquid needed to achieve a predetermined water-repellent effect, the liquid volume determination unit 16 instructs the image forming processing unit 11 to control the amount of pretreatment liquid applied so as to reduce the amount of pretreatment liquid applied to a predetermined level. Conversely, if the amount of pretreatment liquid on the media surface is less than the amount of pretreatment liquid on the media surface, the liquid volume determination unit 16 instructs the image forming processing unit 11 to control the amount of pretreatment liquid applied so as to increase the amount of pretreatment liquid applied to a predetermined level.

[0065] [Liquid Dispensing Method Embodiment] Next, as an embodiment of the liquid ejection method according to the present invention, the flow of liquid ejection control processing that can be performed in an inkjet printer 100 will be described using a flowchart. The flowchart shown in Figure 4 shows an example of the flow of liquid ejection control processing according to this embodiment.

[0066] First, when the liquid ejection process (image forming process) onto the cloth media is started, the application of the pretreatment solution to the cloth media held in the platen begins (S401).

[0067] Next, a media surface detection process is performed to detect the state of the media surface immediately after the pretreatment solution has been applied (S402). The media surface detection process involves, for example, controlling the operation of the optical sensor 151 to optically read the state of the media surface and receiving a detection signal from the optical sensor 151. The media surface detection process also involves controlling the operation of the line sensor 152 to scan and read the state of the media surface in the sub-scanning direction and receiving a detection signal from the line sensor 152.

[0068] The media surface detection process (S402) is a process that detects, for example, the "brightness difference" on the media surface. Here, we will describe a case in which the "brightness difference" is measured based on values ​​detected by the optical sensor 151 or the line sensor 152, or both, and this is used as the judgment criterion. In this case, the reason for using the brightness difference as the judgment criterion is due to the color of the pretreatment solution. In other words, generally, the pretreatment solution used when forming an image on cloth media such as T-shirts is "transparent" or "white". When a "transparent" or "white" liquid is applied, the degree of light reflection on the media surface improves, or the color becomes closer to white. Therefore, compared to the brightness of a media surface without pretreatment solution, the brightness of a media surface with pretreatment solution applied is higher (brighter).

[0069] In other words, the ease with which light reflects off the media surface after the application of the pretreatment solution depends on the amount of pretreatment solution present on the media surface. Furthermore, the conditions used to determine the brightness difference can be arbitrarily set by the user, such as "(brightness of the area where the pretreatment solution was applied) - (brightness of the base fabric media) ≥ 50". That is, a predetermined threshold is used for the brightness difference to determine the amount of pretreatment solution remaining (present) on the media surface.

[0070] Furthermore, when performing the media surface detection process (S402), the operation of the inkjet printer 100 is temporarily stopped, and a message such as "Please check the water repellency of the media surface and set the appropriate settings" is displayed on the control panel 150. The user may then visually observe the application state of the pretreatment solution on the media surface and input the setting values ​​based on the observation results via the control panel 150.

[0071] Based on the results detected by the media surface detection process (S402), the set values, and the conditional expression described above, a determination process is executed (S403). In the determination process, if the state of the media surface satisfies a predetermined condition (i.e., the brightness difference is greater than or equal to the value set by the user) (S403: YES), it is determined that the amount of pre-treatment solution applied is sufficient to achieve sufficient whiteness on the cloth media. In this case, the application process of the pre-treatment solution is terminated (S404).

[0072] After the pretreatment solution application process is completed, the next step is to perform a printing process using white ink to form the desired image on the fabric medium (S405). Subsequently, a printing process using color ink is performed (S406). Once these printing processes are completed, the main process is terminated.

[0073] Furthermore, in the determination process (S403), if the state of the media surface does not meet predetermined conditions (i.e., the brightness difference is not greater than or equal to the user-set value) (S403: NO), it is determined that the amount of pre-treatment solution applied is insufficient to achieve sufficient whiteness on the cloth media. In this case, information is generated to increase the amount of pre-treatment solution so that the amount of pre-treatment solution required to meet the conditions can be confirmed on the media surface, and this information is notified to the image forming processing unit 11 (S407). As a result, the application of pre-treatment solution is carried out until the conditions are met. That is, the application of pre-treatment solution is repeated until the amount of pre-treatment solution necessary to achieve sufficient whiteness on the media surface is secured.

[0074] [Relationship between water repellency of media surface and pretreatment solution] Next, the relationship between the water repellency of the media surface and the amount of pretreatment solution will be explained using the schematic diagram in Figure 5. Depending on the water repellency of the media surface, even when applying the same amount of pretreatment solution, if the water repellency of the media surface is high, the pretreatment solution will not penetrate easily into the fabric media. In this case, as shown in Figure 5(a), the treatment solution S spreads out on the surface M of the fabric media, so the brightness value derived from the results detected by the optical sensor 151, etc., is high in the area where the pretreatment solution was applied. It is then determined that there is a sufficient amount of pretreatment solution to aggregate the white ink on the media surface.

[0075] On the other hand, Figure 5(b) illustrates the case where the water repellency of the media surface is low. In this case, the pretreatment solution easily penetrates into the fabric media. As a result, the brightness of the area where the pretreatment solution is applied becomes not much different from the base color of the fabric media, and tends to be lower than the brightness difference set by the user. In other words, it is easy for a sufficient amount of pretreatment to be retained to agglomerate the white ink.

[0076] In the state shown in Figure 5(b), the determination process (S403) branches off to perform another pretreatment solution application process (S403:NO), so the discharge amount of the pretreatment solution is adjusted to the required amount of pretreatment solution to be applied (S407), and the pretreatment solution application process is performed (S401).

[0077] In the flowchart shown in Figure 4, if the brightness value of the media surface, derived from the detection results of the optical sensor 151 or line sensor 152, is lower than the brightness difference set by the user, the pretreatment is applied to the cloth media again. The application of the pretreatment solution is repeated until the amount necessary to achieve sufficient whiteness is secured.

[0078] Figure 6 illustrates the state of the pretreatment solution on the media surface after the pretreatment solution application process (S401) has been performed three times. Assume that the state after the first pretreatment solution application process (S401) is as shown in Figure 5(b). That is, after the pretreatment solution has been applied once, the amount of pretreatment solution remaining on the media surface is small, as shown in Figure 5(b). Figure 6(a) shows the state of the media surface after the second pretreatment solution application process (S401) has been performed after this first process (S401). In other words, Figure 6(a) illustrates the state after the pretreatment solution application process (S401) has been performed twice. As illustrated in Figure 6(a), by applying the pretreatment solution multiple times, the amount of pretreatment solution remaining on the media surface can be controlled.

[0079] This repeated coating process adjusts the amount of pretreatment solution remaining on the media surface. When the resulting brightness difference exceeds the user-defined level, it is determined that a sufficient amount of pretreatment solution has been applied. At this point, the process moves to printing the desired image onto the media using white and color inks, thereby improving image quality. Furthermore, to address situations where the brightness difference does not exceed a predetermined level even after multiple repetitions, the maximum number of repetitions can be arbitrarily set by the user. This setting can be implemented as a configuration item in the inkjet printer 100.

[0080] Therefore, the number of application cycles is controlled according to the condition of the media surface immediately after application of the pretreatment solution. This allows for the application of a suitable amount of pretreatment solution to the media surface.

[0081] In this embodiment, the determination process (S403) uses "brightness difference" as the criterion for determining whether the amount of pretreatment solution applied is sufficient, but this embodiment is not limited to this. For example, "light reflectance" can be used as the criterion instead of "brightness difference". In this case, a sensor that measures light reflectance is used to measure the value and determine the required amount of pretreatment solution to be applied.

[0082] The optical sensor 151 is mounted on a carriage 110 that scans the discharge head 118 for dispensing the pretreatment liquid. Therefore, the media surface detection process (S402) using the optical sensor 151 has the advantage that detection (measurement or imaging) can be performed simultaneously with the application of the pretreatment liquid, thus reducing the time required for detection (measurement or imaging).

[0083] Furthermore, by mounting the line sensor 152 in the direction of movement of the transport platen 101, it is possible to configure the system to detect (measure) the state of the media surface simultaneously with the transport of the transport platen 101. When the media surface detection process (S402) is performed using the line sensor 152, if the pretreatment liquid easily penetrates the cloth media, it is possible to measure it all at once after it has sufficiently penetrated. Therefore, this is advantageous when using cloth media that easily penetrates. In other words, it is possible to avoid a situation where the state is measured immediately after application of the pretreatment liquid, before it has sufficiently penetrated the cloth media, and when white ink is applied, there is not enough pretreatment liquid remaining on the media surface.

[0084] Furthermore, the media surface detection process (S402) using the line sensor 152 has the advantage of being usable even when the inkjet printer 100 uses a configuration in which the pretreatment solution is applied using a line-shaped spray nozzle instead of the ejection head 118 inside the device housing. In other words, when measuring together with carriage scanning, the elapsed time since the application of the pretreatment solution differs before and after the transport platen 101, whereas with a line-shaped nozzle, the measurement can be performed all at once, which is an advantage.

[0085] It should be noted that the present invention is not limited to the embodiments described above, and various modifications are possible without departing from the technical essence, and all technical matters included in the technical concept described in the claims are subject to the present invention. The above embodiments are shown as preferred examples, but those skilled in the art can realize various modifications from the disclosed content. Such modifications are also included in the technical scope described in the claims. [Explanation of symbols]

[0086] 10: Control Unit 11: Image forming processing unit 12: Liquid Discharge Control Unit 13: Head movement control unit 14: Platen movement control unit 15: Media Reading Department 16: Liquid volume determination unit 17: Re-image formation instruction reception unit 100: Inkjet printer 101: Conveyor Platen 110: Carriage 120: Control Unit 150: Control Panel 151: Optical sensor 152: Line Sensor [Prior art documents] [Patent Documents]

[0087] [Patent Document 1] Japanese Patent Publication No. 2009-220527

Claims

1. A liquid dispensing device that dispenses liquid onto a cloth media, A treatment liquid for controlling the cohesiveness of other liquids on the surface of the fabric medium having a black background color, comprising a treatment liquid application unit for applying the transparent or white treatment liquid to the fabric medium, A media surface state detection unit that detects the difference in brightness between the surface brightness of the cloth media and the surface to which the processing liquid has been applied, A treatment liquid amount determination unit that determines the water repellency on the surface caused by the treatment liquid applied to the surface based on the difference in brightness, The system includes a control unit that controls the amount of treatment liquid applied by the treatment liquid application unit based on the determination result of the water repellency on the surface by the treatment liquid amount determination unit, The control unit, In controlling the amount of coating, when the water repellency of the surface is higher than a predetermined standard, the number of times the treatment solution is applied is reduced, and when the water repellency of the surface is lower than a predetermined standard, the number of times the treatment solution is applied is increased. A liquid dispensing device characterized by the following features.

2. The control unit controls the detection operation by the media surface state detection unit immediately after the processing liquid is applied to the surface in the processing liquid application unit. The liquid dispensing device according to claim 1.

3. A liquid dispensing method for dispensing liquid onto a cloth media, A treatment liquid for controlling the cohesiveness of other liquids on the surface of the cloth medium having a black background color, wherein the transparent or white treatment liquid is applied to the cloth medium. The difference in brightness between the surface brightness of the cloth media and the surface to which the processing liquid is applied is detected. Based on the difference in brightness, the water repellency on the surface caused by the treatment liquid applied to the surface is determined. Based on the determination result of the water repellency on the surface, the amount of treatment solution applied is reduced when the water repellency of the surface is higher than a predetermined standard, and increased when the water repellency of the surface is lower than a predetermined standard. A liquid dispensing method characterized by the following:

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