JP7363358B2 - Liquid discharge device, liquid discharge method, and program - Google Patents

Description

The present invention relates to a liquid ejection device, a liquid ejection method, and a program.

2. Description of the Related Art Conventionally, devices are known that form an image by depositing ejected liquid such as ink onto a recording medium such as cloth. In such devices, in order to properly develop the color ink on the cloth, the cloth may be coated with white ink before the color ink is applied. At this time, the amount of mist generated due to ink ejection may increase due to the large amount of white ink deposited.

The technology for suppressing mist includes a first ejection head that ejects black ink, a second ejection head that ejects a liquid that aggregates or precipitates components in the ink, and a plurality of third ejection heads that eject color ink. A technique has been disclosed in which the third ejection head is retracted when performing monochrome printing using only the first ejection head (for example, see Patent Document 1).

Further, a technique has been disclosed that limits usable print modes among a plurality of print modes based on the measurement result of the distance between the ejection head and the recording medium (see, for example, Patent Document 2).

Furthermore, a technique has been disclosed that acquires recording conditions (image forming conditions) related to mist generation and sets mist reduction conditions according to the recording conditions from among a plurality of mist reduction conditions (for example, Patent Document (See 3).

However, although the technique disclosed in Patent Document 1 can suppress the adhesion of mist to the ejection head, it cannot suppress the generation of mist itself, and the mist may scatter within the apparatus. Furthermore, in the technique disclosed in Patent Document 2, the usable print modes are limited, so that a desired print mode cannot be selected, which may reduce printing productivity. Furthermore, with the technique of Patent Document 3, the desired mist suppression effect may not be obtained in some cases.

The disclosed technology aims to suppress mist without reducing productivity.

A liquid ejection device according to one aspect of the disclosed technology includes a liquid ejection head that ejects at least white liquid onto a recording medium , a movable part that moves the liquid ejection head in a predetermined direction, and a holding part that holds the recording medium. a mechanism that changes the distance between the movable part and the holding part by changing the height direction positions of the movable part and the holding part; an amount of white liquid used by the liquid ejection head; predicting the amount of mist generated based on at least one of the following: a distance between the recording medium and the holding unit; an image forming position on the mounting member on which the recording medium is mounted; and a temperature or humidity of the liquid ejecting device. a mist generation amount predicting unit ; , an interval control section that changes the position of the movable section .

According to the disclosed technology, mist can be suppressed without reducing productivity.

1 is a perspective view of a configuration example of an image imparting system according to an embodiment. It is a perspective view when a cassette is removed from the same system and inserted into a heating device. 1 is a perspective view of a configuration example of an image forming apparatus according to an embodiment. FIG. 4 is a perspective view of a configuration example of the device viewed from a different direction from FIG. 3; 1 is a diagram illustrating a configuration example of a carriage of an image forming apparatus according to an embodiment. FIG. 2 is a block diagram of an example hardware configuration of a control unit of the device. FIG. 2 is a block diagram of an example of a functional configuration of a control unit according to the first embodiment. 3 is a flowchart of an example of image forming processing performed by the same apparatus. FIG. 3 is a diagram illustrating an example of the relationship between the number of images formed and the degree of contamination within the image forming apparatus. 3 is a flowchart of an example of white ink usage prediction processing. FIG. 3 is a block diagram of an example of a functional configuration of a control unit according to a second embodiment. 12 is a flowchart of another example of white ink usage prediction processing. FIG. 7 is a perspective view showing a configuration example of an image forming apparatus according to a third embodiment. FIG. 7 is a top view showing a configuration example of an image forming apparatus according to a third embodiment. FIG. 7 is a front view showing a configuration example of an image forming apparatus according to a third embodiment.

Hereinafter, embodiments for carrying out the invention will be described with reference to the drawings. In each drawing, the same components are designated by the same reference numerals, and redundant explanations may be omitted.

The liquid ejection apparatus according to the embodiment includes a liquid ejection head that ejects at least white liquid onto a recording medium, and narrows the distance between the liquid ejection head and the recording medium based on the amount of mist generated by ejection of the white liquid. change to For example, when the amount of mist generated during liquid ejection is equal to or greater than a predetermined threshold, the distance between the liquid ejection head and the recording medium is changed to be narrower. This suppresses mist without reducing productivity.

The following describes an image forming device (an example of a liquid ejecting device) that ejects ink (an example of a liquid) to form an image on fabric (an example of a recording medium), and an image forming device that heats the fabric after image formation to fix the image on the fabric. An embodiment will be described by taking as an example an image providing system including a heating device for heating the image.

Note that the terms "image formation", "printing", "printing", and "recording" in the embodiments have the same meaning.

<Example of overall configuration of image imparting system 1000>
First, an example of the configuration of an image imparting system 1000 according to an embodiment will be described with reference to FIGS. 1 and 2. FIG. 1 is a perspective view illustrating an example of the configuration of an image providing system 1000, and FIG. 2 is a perspective view illustrating a case where a cassette is removed from the system and inserted into a heating device.

The image imparting system 1000 includes a cassette 200, an image forming apparatus 1, and a heating device 500. The cassette 200 is a member for holding the portion of the fabric 400 on which an image is to be formed in a flat state, and is shared by both the image forming apparatus 1 and the heating device 500.

The image forming apparatus 1 has a removable cassette 200 as an example of a holding section, and forms an image on the fabric 400 held by the cassette 200. Further, the heating device 500 has a removable cassette 200, and heats the fabric 400 on which the image is formed together with the cassette 200 to fix the image on the fabric 400.

Note that although the image forming apparatus 1 is shown here as being placed on the heating apparatus 500, the image forming apparatus 1 and the heating apparatus 500 are separate bodies, and may be placed side by side or separated from each other. You can also do it.

When applying an image to fabric 400 using this image forming system 1000, as shown in FIG. form.

After the image formation is completed, the front door 502 of the heating device 500 is opened, the cassette 200 holding the fabric 400 is taken out from the image forming device 1, and the cassette 200 is directly attached to the heating device 500 (see FIG. 2). Thereafter, the front door 502 of the heating device 500 is closed, and the heating device 500 heats the fabric 400 together with the cassette 200, thereby fixing the image formed on the fabric 400 to the fabric 400.

<Configuration example of image forming apparatus 1>
Next, the configuration of the image forming apparatus 1 will be explained with reference to FIGS. 3 to 5.

3 is a perspective view illustrating an example of the configuration of the image forming apparatus 1, FIG. 4 is a perspective view illustrating an example of the configuration of the image forming apparatus 1 viewed from a direction different from that in FIG. 3, and FIG. 5 is a perspective view illustrating an example of the configuration of the image forming apparatus 1. It is a figure explaining the example of composition of carriage 121 with which.

The image forming apparatus 1 includes a stage 111 that removably holds a cassette 200 holding a fabric 400 and moves forward and backward within an apparatus main body 100, and an image forming section 112 that forms an image on the fabric 400 held in the cassette 200. It is equipped with

Here, the fabric 400 is one made of a single piece of fabric such as a handkerchief or a towel, or one that has been processed into clothing such as a T-shirt or sweatshirt, or one that is part of a product such as a tote bag. etc.

The stage 111 is provided on a transport structure 113 that is held so as to be movable back and forth in the direction of arrow Y (sub-scanning direction) with respect to the apparatus main body 100. Specifically, the stage 111 is connected to a transport structure 113, and the slider section 116 of the transport structure 113 is connected to a transport guide member 115 disposed on the bottom housing section 114 of the apparatus main body 100 along the direction of arrow Y. is movably held by Note that the stage 111 (transport structure 113) is reciprocated in the direction of arrow Y by a sub-scanning motor M2 (see FIG. 6).

The image forming unit 112 includes a carriage 121 that moves in the direction of arrow X (main scanning direction) with respect to the stage 111. The carriage 121, which is an example of a movable part, is movably held by a guide member 123 arranged along the arrow X direction, and is moved back and forth in the arrow X direction by a main scanning motor M1 via a scanning mechanism such as a timing belt 125. will be moved. Further, the carriage 121 is equipped with an ink ejection head 122 as a liquid ejection head that forms an image by ejecting ink onto the surface of cloth.

As shown in FIG. 5, a plurality of ink ejection heads 122 (122c, 122m, 122y, 122k, 122w1, 122w2) are mounted on the carriage 121. Each of the ink ejection heads 122 includes a large number of nozzles (ejection ports) for ejecting ink, and is arranged in the direction of arrow X with respect to the stage 111.

The ink ejection head 122c ejects cyan ink, and the ink ejection head 122m ejects magenta ink. Further, the ink ejection head 122y ejects yellow ink, and the ink ejection head 122k ejects black ink. Further, both the ink ejection head 122w1 and the ink ejection head 122w2 eject white ink. Note that when the ink ejection head 122w1 and the ink ejection head 122w2 are not distinguished, they are collectively referred to as the ink ejection head 122w.

Ink of each color is supplied to each ink ejection head 122 from a tank mounted on the carriage 121 for each color. Note that the color and number of inks may be arbitrary and can be changed as necessary.

Returning to FIGS. 3 and 4, in the image forming apparatus 1, the cassette 200 is mounted and held on the stage 111 in the apparatus main body 100 with the fabric 400 set on the platen member 300 of the cassette 200. Then, by repeating the movement of the stage 111 in the direction of the arrow Y and the reciprocating movement of the ink ejection head 122 in the direction of the arrow X, a desired image is formed on the fabric 400. Here, the platen member 300 is an example of a mounting member.

In this case, the stage 111 can be moved up and down in the direction of the arrow Z by a stage lift motor M3 (see FIG. 6), and by raising and lowering the stage 111 according to the thickness of the fabric 400, the fabric 400 and the ink ejection head 122 can be moved up and down. The gap can be adjusted to a predetermined gap. Note that the image forming unit 112 including the carriage 121 may be configured to be able to move up and down.

<Example of hardware configuration of control unit 700>
Next, the hardware configuration of the control unit 700 of the image forming apparatus 1 will be described with reference to FIG. 6. FIG. 6 is a block diagram illustrating an example of the hardware configuration of the control unit 700.

As shown in FIG. 6, the control unit 700 includes a CPU (Central Processing Unit) 701, a ROM (Read Only Memory) 702, a RAM (Random Access Memory) 703, an NVRAM (Non-Volatile RAM) 704, and an ASIC. (Application Specific Integrated Circuit) 705.

The CPU 701 centrally controls the entire image forming apparatus 1 . The ROM 702 is a memory that stores programs executed by the CPU 701 and other fixed data. The RAM 703 is a memory that temporarily stores image data, print data, and the like. Here, the CPU 701, ROM 702, and RAM 703 correspond to the main control unit 700A (computer) of the image forming apparatus 1.

The NVRAM 704 is a nonvolatile memory that can hold data even while the image forming apparatus 1 is powered off. The ASIC 705 processes various types of signal processing, image processing such as sorting, and other input/output signals for controlling the entire image forming apparatus 1 .

The control unit 700 also includes a host I/F (Interface) 706, an I/O (Input/Output) 707, a head drive control unit 708, a main scanning motor drive unit 709, and a sub-scanning motor drive unit 710. , and a lifting motor drive section 711.

The host I/F 706 sends and receives data and signals to and from the host H side. The head drive control unit 708 generates a drive waveform for driving and controlling the ink ejection head 122.

The main scanning motor drive unit 709 drives the main scanning motor M1, and the main scanning motor M1 moves the carriage 121 in the X direction. The sub-scanning motor drive unit 710 drives the sub-scanning motor M2, and the sub-scanning motor M2 is driven to move the stage 111 in the Y direction. The elevating motor drive unit 711 drives each of the stage elevating motor M3 and the image forming unit elevating motor M4. The stage lift motor M3 is driven to move the stage 111 up and down in the Z direction, and the image forming unit lift motor M4 is driven to move the image forming unit 112 up and down in the Z direction.

The I/O 707 acquires information from various sensors provided in the image forming apparatus 1, such as a temperature sensor 713 and a humidity sensor 714, and extracts information necessary for controlling each part of the image forming apparatus 1. Further, an operation panel 712 for inputting and displaying various information is connected to the control unit 700.

The control unit 700 receives image data from a host H side such as an information processing device such as a PC (Personal Computer), an image reading device such as an image scanner, or an imaging device such as a digital camera, and sends the image data to the host I/F 706 via a cable or network. Receive at. The CPU 701 and ASIC 705 analyze the image data received by the host I/F 706 and generate print data.

[First embodiment]
<Example of functional configuration of control unit 700>
Next, the functional configuration of the control section 700 of the image forming apparatus 1 will be described with reference to FIG. 7. FIG. 7 is a block diagram illustrating an example of the functional configuration of the control unit 700.

As shown in FIG. 7, the control unit 700 includes a white ink usage determination unit 751, a setting information storage unit 752, an image forming position acquisition unit 753, a usage amount prediction unit 754, a mist generation amount prediction unit 755, It includes an interval control section 756, a holding section height variable section 757, and a movable section height variable section 758.

Among these, the functions of the white ink usage determination unit 751, image forming position acquisition unit 753, usage amount prediction unit 754, mist generation amount prediction unit 755, and interval control unit 756 are executed by the CPU 701 in FIG. This is achieved by executing. Further, the function of the setting information storage section 752 is realized by the NVRAM 704 and the like, and the functions of the holding section height variable section 757 and the movable section height variable section 758 are realized by the elevating motor drive section 711 and the like.

The white ink usage determining unit 751 determines whether or not to use white ink in image formation based on the image data input from the host H, and if it is used, the white ink usage determination unit 751 transmits the image data to the image forming position acquisition unit 753 and the usage It is output to each of the quantity prediction units 754.

The setting information storage unit 752 stores at least the standard distance information between the ink ejection head 122 and the cloth 400, the position information of the outer circumference of the platen member 300, among various setting information for the image forming apparatus 1 to perform image formation. is stored. Here, the standard interval information is information indicating the interval between the ink ejection head 122 and the cloth 400, which is set as a standard value. Further, the positional information of the outer circumferential portion of the platen member 300 is information indicating the relative position of the outer circumferential portion of the platen member 300 with respect to a reference position arbitrarily set in the image forming apparatus 1.

The image forming position acquisition section 753 acquires the positional information of the edge of the image formed on the cloth 400 based on the image data, and also refers to the setting information storage section 752 to acquire the positional information of the outer periphery of the platen member 300. and calculate the distance between them. Then, based on the distance, information on the image forming position on the platen member 300 is acquired, and this is output to the mist generation amount prediction section 755.

Further, the usage amount prediction unit 754 predicts the usage amount of white ink used (discharged) in image formation based on the image density information acquired from the image data, and uses the predicted value as the mist generation amount prediction unit. 755.

The mist generation amount prediction unit 755 uses the predicted value of the amount of white ink used, the information on the image forming position, the standard interval information acquired from the setting information storage unit 752, and the ambient temperature of the image forming apparatus 1 input from the temperature sensor 713. Based on at least one of (environmental temperature) information and ambient humidity (environmental humidity) information of the image forming apparatus 1 input from the humidity sensor 714, the amount of white ink mist generated during image formation is predicted. Note that the temperature may be the temperature inside the image forming apparatus 1, and the humidity may be the humidity inside the image forming apparatus 1.

The amount of white ink mist generated can be predicted using the following equation (1).
M=ΔW・α・β・γ ...(1)
In equation (1), M represents the amount of white ink mist generated, ΔW represents the amount of white ink used in image formation, and α is predetermined according to the distance between the ink ejection head 122 and the fabric 400. represents the calculated coefficient. Further, β represents a coefficient predetermined according to the temperature and/or humidity within the image forming apparatus 1, and γ represents a coefficient predetermined according to the image forming position.

After the prediction process is completed, the mist generation amount prediction section 755 outputs the predicted value to the interval control section 756.

The interval control unit 756 compares a predetermined threshold value of the amount of mist generation stored in the setting information storage unit 752 or the like with the predicted value by the amount of mist generation prediction unit 755. Then, when the predicted value is equal to or greater than the threshold value, the distance between the ink ejection head 122 and the cloth 400 is changed to be narrower than the standard distance. In other words, when the amount of mist generated during image formation increases and exceeds the threshold value, the interval control unit 756 compares the interval between the ink ejection head 122 and the fabric 400 with the standard interval in order to suppress the mist. Change it to make it narrower.

In order to change the interval, the interval control section 756 controls the holding section height variable section 757 to drive the stage lift motor M3 that raises and lowers the stage 111 on which the cassette 200 as a holding section is attached. Raise 200. Note that in order to stop the stage lift motor M3 when the stage 111 has risen to a predetermined height, a sensor may be provided that detects that the stage 111 has reached a predetermined position.

Alternatively, the interval control section 756 controls the movable section height variable section 758 and drives the image forming section elevating motor M4 that raises and lowers the image forming section 112 including the carriage 121 as a movable section. lower it.

When the image forming apparatus 1 has a function of automatically switching the height of the carriage 121 when the recording medium is an envelope and the height of the carriage 121 when the recording medium is paper according to the recording medium type information, , the height of the image forming section 112 may be changed using this function.

In this way, the distance between the ink ejection head 122 and the fabric 400 can be narrowed compared to the standard distance. In addition, the interval control unit 756 can also make the interval between the ink ejection head 122 and the fabric 400 narrower compared to the standard interval by causing both the cassette 200 to rise and the image forming unit 112 to lower. .

<Example of the relationship between the number of images to be formed and the degree of contamination inside the image forming apparatus 1>
Next, the relationship between the number of images formed by the image forming apparatus 1 and the degree of contamination within the image forming apparatus 1 will be described with reference to FIG. FIG. 8 is a diagram illustrating an example of the relationship between the number of images to be formed and the degree of contamination within the image forming apparatus 1. The horizontal axis in FIG. 8 indicates the number of fabrics 400 on which images have been formed, and the vertical axis indicates the degree of contamination within the image forming apparatus 1.

Here, contamination refers to dirt inside the image forming apparatus 1 due to scattering of mist. Furthermore, the degree of contamination refers to the state of mist scattering expressed as a percentage, with the state of mist scattering when an abnormality occurs in image formation by the image forming apparatus 1 due to mist being taken as 100%. The larger the value on the vertical axis, the greater the amount of mist scattered within the image forming apparatus 1, indicating that the pollution caused by the mist is more severe.

Note that even if the degree of contamination reaches 100%, it is possible to improve the degree of contamination to nearly 0% by cleaning the inside of the image forming apparatus 1.

Further, in FIG. 8, a graph 81 indicated by a solid line indicates a case where the distance between the ink ejection head 122 and the fabric 400 is 10.0 mm, and a graph 82 indicated by a broken line indicates a case where the distance is 7.5 mm. There is. Further, a graph 83 indicated by a dashed line indicates the case where the interval is 5.0 mm, a graph 84 indicated by the double dot chain line indicates the case when the interval is 3.0 mm, and a graph 85 indicated by the dotted line indicates the case where the interval is 5.0 mm. is 2.0 mm.

As can be seen from FIG. 8, as the distance between the ink ejection head 122 and the fabric 400 increases, the degree of contamination increases with the number of sheets on which images are formed.

Here, for example, if more ink is ejected during image formation than for an image using 5 ml of white ink, the number of sheets on which images are formed will be reduced to reach a degree of contamination by mist of 100%. In other words, the degree of contamination by mist reaches 100% at an earlier stage after starting image formation.

On the other hand, when the amount of ink ejected during image formation is small, the number of sheets on which images are formed becomes large when the degree of contamination by mist reaches 100%. In other words, more images can be formed after starting image formation until the degree of contamination by mist reaches 100%.

Note that the example shown in FIG. 8 is in a normal temperature and normal humidity environment (for example, 23±2° C., 50±5%). The amount of mist generated also changes depending on the environmental temperature and humidity. For example, when the environmental temperature is high, less mist is generated, and when the environmental temperature is low, more mist is generated. Conversely, depending on the combination of inks and ink ejection heads 122, more mist may be generated when the environmental temperature is high, and less mist may be generated when the environmental temperature is low.

<About each coefficient for predicting the amount of mist generation>
Next, each coefficient in the above-mentioned equation (1) will be explained in more detail.

(coefficient α)
First, the coefficient α determined according to the distance between the ink ejection head 122 and the cloth 400 will be explained. The coefficient α can be determined at the time of designing the image forming apparatus 1 by conducting an experiment or simulation of a change in mist amount depending on the distance between the ink ejection head 122 and the cloth 400. Alternatively, the coefficient α may be displayed on the user interface such as the operation panel 712 so that the user of the image forming apparatus 1 can recognize and set the mist generation situation during actual use of the image forming apparatus 1 based on the image forming results. An input section may also be provided.

(coefficient β)
Next, the coefficient β determined depending on the temperature and/or humidity inside the image forming apparatus 1 will be explained.

Even if the distance between the ink ejection head 122 and the fabric 400 is wide, mist generation may be reduced depending on the temperature and/or humidity. In this case, the coefficient β is made smaller than 1 to reduce the predicted value of the amount of mist generation, thereby increasing the margin for the threshold value.

Also, if the distance between the ink ejection head 122 and the fabric 400 is a little narrower than usual (for example, when the standard distance is 5 mm and the narrowed distance is 2 mm, and image formation is performed at a distance of about 4 mm), However, mist generation may increase depending on the temperature and/or humidity. In this case, the margin for the threshold value is reduced by increasing the predicted value of the amount of mist generation by making the coefficient β larger than 1.

In this way, the conditions for forming an image with a wide gap between the ink ejection head 122 and the fabric 400 and the conditions for forming an image with a narrow gap can be made more appropriate.

Note that the coefficient β depending on the temperature and/or humidity varies depending on the type of ink, the type of ink ejection head, and the drive waveform of the ink ejection head. Therefore, it is preferable to determine the coefficient β through experiments, simulations, etc. at the design stage of the image forming apparatus 1. For example, if it is found as a result of evaluation at the time of designing the image forming apparatus 1 that mist tends to increase as the temperature increases, the coefficient β is increased.

Specific examples of the coefficient β for each temperature and humidity include the following.
25℃, 50%: 1.0
35℃, 50%: 2.0
15℃, 50%: 0.5
25℃, 10%: 1.2
25℃, 25%: 0.8
In addition, the coefficient β can be input on the user interface such as the operation panel 712 so that the user of the image forming apparatus 1 can recognize and set the mist generation situation during actual use of the image forming apparatus 1 based on the image forming results, etc. A section may be provided.

(coefficient γ)
Next, the coefficient γ determined depending on the image forming position will be explained.

The amount of mist generated also changes depending on the position on the platen member 300 where image formation is performed. In the image forming apparatus 1, since ink is ejected while the carriage 121 moves, the ejected ink flows in the moving direction of the carriage 121 due to the influence of inertia. In this case, if there is cloth 400 or platen member 300 before the ink flows, it will land on cloth 400 or platen member 300, so no mist will be generated due to ink not landing at a predetermined position.

However, when ink is ejected near the outer periphery of the platen member 300, the ink may flow to the outside of the platen member and may not land on the cloth 400 or the platen member 300. These inks may not land in a predetermined position and become a mist floating inside the image forming apparatus 1.

Therefore, by changing the coefficient γ according to the image forming position, conditions for forming an image with a wide gap between the ink ejection head 122 and the fabric 400 and conditions for forming an image with a narrow gap can be set. , can be made more appropriate.

The following examples are given as the coefficient γ for each image forming position.
When the image forming position is near the left and right outer periphery of the platen: 1.0
When the image forming position is sufficiently far from the left and right outer periphery: 0.8
In addition to optimizing the conditions for changing the distance between the ink ejection head 122 and the fabric 400 by changing the coefficient γ, mist can also be suppressed by changing the image forming position to the center of the platen member 300. can. The image forming position changing function may be installed as a function of the main body of the image forming apparatus 1, or may be installed as a function of a RIP (Raster Image Processor) or a printer driver installed in the ASIC 705 or the like.

<Example of image formation processing by control unit 700>
Next, image forming processing by the control unit 700 will be described with reference to FIG. 9. FIG. 9 is a flowchart illustrating an example of image forming processing by the control unit 700.

First, in step S91, the white ink usage determination unit 751 receives image data from the host H.

Subsequently, in step S92, the white ink use determining unit 751 determines whether white ink is to be used in image formation based on the input image data.

If it is determined in step S92 that white ink is not used (step S92, No), the process moves to step S98. On the other hand, if it is determined that white ink is to be used (step S92, Yes), the white ink usage determination section 751 outputs the image data to the image forming position acquisition section 753 and the usage amount prediction section 754, respectively.

Subsequently, in step S93, the image forming position acquisition unit 753 acquires position information of the edge of the image formed on the fabric 400 based on the input image data, and also refers to the setting information storage unit 752 to determine the position of the platen. The positional information of the outer circumference of the member 300 is acquired. Then, the distance between the two is calculated, and information on the image forming position using white ink is obtained based on the distance. Thereafter, the acquired information is output to the mist generation amount prediction unit 755.

Subsequently, in step S94, the usage amount prediction unit 754 predicts the amount of white ink used in image formation based on the image density information obtained from the input image data, and uses the predicted value as a mist generation amount prediction. 755. Note that the processing of the usage amount prediction unit 754 will be separately described in detail in FIG. 10 as well.

Here, the order of steps S93 and S94 may be changed as appropriate, or both may be executed in parallel. Further, if the mist generation amount prediction unit 755 does not use the information on the image forming position to predict the amount of mist generation, the process of step S93 may be omitted. Further, if the usage amount of white ink is not used, the process of step S94 may be omitted.

Subsequently, in step S95, the mist generation amount prediction unit 755 calculates the predicted value of the white ink usage amount, the information on the image forming position, the standard interval information acquired from the setting information storage unit 752, and the information input from the temperature sensor 713. Based on at least one of the temperature information around the image forming apparatus 1 and the humidity information around the image forming apparatus 1 input from the humidity sensor 714, the amount of white ink mist generated during image formation is predicted. Then, the predicted value is output to the interval control section 756.

Subsequently, in step S96, the interval control unit 756 compares a predetermined threshold value of the amount of mist generation stored in the setting information storage unit 752 etc. with the predicted value by the amount of mist generation prediction unit 755, and determines the amount of mist generation. It is determined whether or not is greater than or equal to a threshold value.

If it is determined in step S95 that the amount of mist generation is not equal to or greater than the threshold value (step S96, No), the process moves to step S98. On the other hand, if it is determined that the amount of mist generation is equal to or greater than the threshold (step S96, Yes), the process moves to step S97.

Subsequently, in step S97, the interval control section 756 controls the holding section height variable section 757 to drive the stage lift motor M3 that raises and lowers the stage 111 on which the cassette 200 is mounted, thereby raising the cassette 200.

Alternatively, the interval control section 756 may lower the image forming section 112 by controlling the movable section height variable section 758 and driving the image forming section lifting motor M4 that moves up and down the image forming section 112 including the carriage 121. good.

In this way, the interval control unit 756 changes the interval between the ink ejection head 122 and the fabric 400 so that it is narrower than the standard interval.

Subsequently, in step S98, the control unit 700 executes image formation processing, and the processing ends after the image formation.

In this way, the control unit 700 can execute image forming processing.

<Prediction processing of white ink usage by control unit 700>
Next, the process of predicting the amount of white ink used by the control unit 700 will be described with reference to FIG. FIG. 10 is a flowchart illustrating an example of white ink usage prediction processing performed by the control unit 700. Note that FIG. 10 corresponds to the process of step S94 in FIG.

First, in step S<b>101 , the usage amount prediction unit 754 inputs image data that is a color image via the white ink usage determination unit 751 .

Subsequently, in step S102, the usage amount prediction unit 754 converts the image data into an 8-bit grayscale image.

Subsequently, in step S103, the usage amount prediction unit 754 calculates and predicts the usage amount of white ink from the density (pixel value) information of the grayscale image.

This calculation can be performed by performing calculation using a predetermined proportionality coefficient based on the 0 to 255 gradations of pixel values of the gray scale image. Alternatively, for gradations 0 to 63, white ink is not used (not ejected), for gradations 64 to 127, small ink droplets (droplets) are used, and for gradations 128 to 256, large ink droplets (large droplets) are used. It may also be done based on the use of (drops), etc.

In this way, the control unit 700 can predict the amount of white ink used.

Note that although FIG. 10 shows an example of 8-bit image data, the present invention can also be applied to the case where image data with another number of gradations such as 16 bits is used by changing the number of gradations.

In addition, although FIG. 10 shows an example in which the usage prediction unit 754 converts the image data into an 8-bit grayscale image, the usage amount is The prediction unit 754 may receive image data of a grayscale image.

<Functions and effects of image forming apparatus 1>
As described above, the liquid ejection apparatus according to the embodiment includes the ink ejection head 122 that ejects at least white ink onto the fabric 400, and based on the amount of mist generated by ejection of the white liquid, the ink ejection head and the recording medium Change the distance between the two. For example, when the amount of mist generated during ink ejection is equal to or greater than a predetermined threshold, the distance between the ink ejection head 122 and the fabric 400 is changed to be narrower.

The smaller the distance between the ink ejection head 122 and the fabric 400, the less the amount of mist generated. Therefore, by narrowing this distance, mist can be suppressed. Further, at this time, since the usable image forming modes are not limited, there is no reduction in productivity due to the limitation of the image forming modes.

In this way, mist can be suppressed without reducing productivity.

For general image forming apparatuses for fabric, the distance between the ink ejection head and the fabric may be set wide to prevent the ink ejection head from coming into contact with the fluff of the fabric, which is the recording medium. be.

Therefore, in the embodiment, the distance between the ink ejection head 122 and the fabric 400 is narrowed only when the amount of white ink mist generated is predicted to be large enough to affect operations of the image forming apparatus 1 such as image formation. change it so that Thereby, the amount of white ink mist generated during image formation can be suppressed, and the influence of the mist on the operation of the image forming apparatus 1 can be reduced.

More specifically, in normal image formation (when the amount of mist generated is small), the image is formed with the distance between the ink ejection head and the fabric being set to a standard distance of about 5 mm. On the other hand, when the amount of white ink used is large and the amount of mist generated exceeds the threshold value, the number of sheets on which images are formed until the degree of contamination reaches 100% decreases. In other words, the degree of contamination reaches 100% with a small number of images formed. Therefore, in such a case, the distance between the ink ejection head and the cloth is narrowed to about 2 mm to suppress the amount of mist generated.

However, if the distance between the ink ejection head and the fabric is narrowed, the fabric may wrinkle or loosen due to the condition of the fluff on the surface of the fabric used as a recording medium and the placement of the fabric on the platen member. The ink ejection head may rub against the fabric, which may deteriorate the image.

Therefore, in the embodiment, when the amount of mist generated is not equal to or greater than the threshold value, the distance between the ink ejection head and the fabric is set to a standard distance, such as 5 mm, in order to suppress rubbing and improve the stability of image formation. Thereby, it is possible to suppress image deterioration due to rubbing between the ink ejection head and the cloth.

[Second embodiment]
Next, an image forming apparatus 1a according to a second embodiment will be described with reference to FIGS. 11 and 12. First, FIG. 11 is a block diagram illustrating an example of the functional configuration of a control section 700a included in the image forming apparatus 1a according to the present embodiment.

As shown in FIG. 11, the control unit 700a includes a usage amount prediction unit 754a. The usage amount prediction unit 754a predicts the usage amount of white ink based on the ejection data obtained by quantizing the image data input from the host H through the white ink usage determination unit, and uses the prediction result as a mist. It has a function of outputting to the generation amount prediction unit 755.

FIG. 12 is a flowchart illustrating an example of white ink usage prediction processing performed by the control unit 700a. Note that FIG. 12 corresponds to the process of step S94 in FIG.

First, in step S121, the usage amount prediction unit 754a inputs image data, which is a color image, via the white ink usage determination unit 751.

Subsequently, in step S122, the usage amount prediction unit 754a converts the image data into print data in which dot information for image formation is arranged. For this conversion process, a RIP (Raster Image Processor) or a printer driver installed in the ASIC 705 or the like can be used.

Subsequently, in step S123, the usage amount prediction unit 754a obtains the number of white dots in the print data by counting dots.

Subsequently, in step S124, the usage amount prediction unit 754a calculates and predicts the amount of white ink by multiplying the number of white dots by the amount of ink for one dot of white ink.

In this way, the control unit 700a can predict the amount of white ink used.

The functions and effects of the image forming apparatus 1a other than those described above are the same as those described in the first embodiment, so a redundant explanation will be omitted here.

[Third embodiment]
Next, an image forming apparatus 1b according to a third embodiment will be described with reference to FIGS. 13 to 15. Here, FIG. 13 is a perspective view showing a configuration example of the image forming apparatus 1b, FIG. 14 is a top view, and FIG. 15 is a front view.

A carriage 803 on which a head 820 for ejecting ink is mounted moves in the left-right direction of the image forming apparatus 1b along main and sub guide rods by driving a timing belt 802 by a main scanning motor 817. At this time, in order to detect the position, the encoder sheet 801 on which slits are periodically formed or printed is read by a sensor (not shown) on the carriage 803, and the timing is adjusted at the discharge position, and the control signal from the controller board 805 is read. In response to this, the head 820 ejects ink droplets to form an image.

Four heads 820 are mounted on the carriage 803, and each head has two nozzle rows in which a plurality of nozzles are arranged in the sub-scanning direction. Directly above the head 820 in the carriage 803, a head tank (not shown) is provided for temporarily storing ink used for ejection. This head tank is connected to the ink cartridge 806 via an ink supply tube (not shown) and an ink supply pump (not shown), and can receive ink from the ink cartridge 806 as needed. can.

A print medium (T-shirt) is set on the platen 812. The platen 812 is mounted on a platen elevating mechanism (Z-axis) 819, and its position can be adjusted in the vertical direction. The platen lifting mechanism (Z-axis) 819 is mounted on a sub-scanning slider 809, and the slider 809 runs along a sub-scanning guide rail 810, a sub-scanning timing belt 811, and a sub-scanning drive mechanism (not shown). (omitted) and a controller board 805, and is movable in the sub-scanning direction.

When printing on a T-shirt, the following steps are performed.

First, a T-shirt is set on the platen 812.

Subsequently, by operating the operation unit 808, the slider 809 is operated to completely pull the platen 812 toward the rear of the image forming apparatus 1b.

During this retraction, the height detection sensor 813 detects whether or not the T-shirt on the platen 812 collides with the head 820. If the T-shirt collides with the head 820, the retraction of the platen 812 is stopped on the spot. Alternatively, the platen 812 is returned to the T-shirt setting position at the front of the image forming apparatus 1b.

If the drawing of the platen 812 to the rear of the image forming apparatus 1b is completed without any problems, the printer enters a print data standby state.

Here, print data is transmitted from the PC (not shown) to the image forming apparatus 1b. Alternatively, if there is print data stored in the controller board 805 in advance, the print operation is started by selecting that data with the operation unit 808.

When printing starts, the slider 809 first moves the platen 812 to the printing start position.

Subsequently, by moving the carriage 803 once to the right or left (one scan), image formation is performed by ejecting ink. Then, in synchronization with the completion timing of image formation, the platen 812 is moved by the slider 809 to the front side of the image forming apparatus 1b by an appropriate amount of movement (line feed processing). This moves the T-shirt to the next printing position.

After the movement of the slider 809 is completed, the carriage 803 performs one more scan of printing. By repeating one scan of the carriage 803 and the subsequent movement of the slider 809, an image is formed on a desired area of the T-shirt, and when the image formation is completed, the platen 812 is returned to the front of the image forming apparatus 1b. . This completes image formation.

Here, a left empty discharge receiver 815 is provided on the front left side of the image forming apparatus 1b. The left empty ejection receiver 815 is a place where ink in the head 820, which has dried and increased in viscosity due to exposure to air during image formation, is discarded and ejected (dry ejection). Ink is discarded and ejected into the left empty ejection receiver 815 according to instructions from the controller 805 at appropriate timing.

A maintenance mechanism (maintenance unit) 804 is provided on the front right side of the image forming apparatus 1b. The maintenance mechanism 804 includes a mechanism for maintaining and restoring the functions of the head. The maintenance and recovery mechanism is provided with a cap for covering the nozzle surface of the head 820 on which the nozzles are provided, in order to protect the exposed ink portion of the head 820 from drying when the image forming apparatus 1b does not perform image formation. It is being The cap includes a moisturizing cap 821 that has the sole function of covering the nozzle surface and protecting it from drying, and a moisturizing cap 821 that has the function of simply covering the nozzle surface and protecting it from drying. Two types of suction caps 822 are included that have a function of restoring the head 820 to an appropriate state by suctioning viscous ink or the like.

The ink sucked by the suction pump is discharged into a waste liquid bottle (not shown) via a waste liquid tube (not shown). The maintenance mechanism also includes a wiper 823 for cleaning excess ink remaining on the nozzle surface after suction and restoring the nozzle condition. By wiping the nozzle surface with the wiper 823 after the head suction, excess ink is scraped off and the meniscus in the nozzle is brought to a normal state.

The first and second embodiments can also be applied to such an image forming apparatus 1b. The effects are the same as those described in the first embodiment, so redundant explanation will be omitted here.

Although the embodiments have been described above, the present invention is not limited to the above specifically disclosed embodiments, and various modifications and changes can be made without departing from the scope of the claims. .

Note that the "liquid" in the embodiments is not particularly limited as long as it has a viscosity and surface tension that can be discharged from the head, but the "liquid" may have a viscosity of 30 mPa・s or less at room temperature and normal pressure, or by heating or cooling. It is preferable that the More specifically, solvents such as water and organic solvents, coloring agents such as dyes and pigments, functional materials such as polymerizable compounds, resins, and surfactants, and biocompatible materials such as DNA, amino acids, proteins, and calcium. , edible materials such as natural pigments, etc., and these include, for example, inkjet inks, surface treatment liquids, constituent elements of electronic devices and light emitting devices, and formation of electronic circuit resist patterns. It can be used for purposes such as a liquid for use in liquids, a material liquid for three-dimensional modeling, and the like.

Furthermore, a "liquid ejection head" is a functional component that ejects and jets liquid from a nozzle.

Piezoelectric actuators (laminated piezoelectric elements and thin film piezoelectric elements), thermal actuators using electrothermal conversion elements such as heat-generating resistors, electrostatic actuators consisting of a diaphragm and opposing electrodes, etc. are used as energy generation sources for discharging liquid. Includes things that do.

Embodiments also include a liquid ejection method. For example, the liquid ejection method includes the step of ejecting at least a white liquid onto a recording medium, and narrowing the interval between the liquid ejection head and the recording medium when the amount of mist generated by ejecting the white liquid is equal to or greater than a predetermined threshold. and a step of changing it so that it does. With such a liquid ejection method, the same effects as the above-described liquid ejection device can be obtained.

The embodiments also include programs. For example, the program may eject at least a white liquid onto a recording medium, and when the amount of mist generated by ejecting the white liquid is equal to or greater than a predetermined threshold, the program changes to narrow the distance between the liquid ejection head and the recording medium. cause the computer to perform the processing to be performed. With such a program, it is possible to obtain the same effects as the liquid ejecting device described above.

1 Image forming device (an example of liquid ejection device)
100 Apparatus main body 111 Stage 112 Image forming section 121 Carriage (an example of a movable part)
122 Ink discharge head (an example of liquid discharge head)
200 cassette (example of holding part)
300 Platen member (an example of a mounting member)
400 Fabric (an example of recording medium)
500 Heating device 700 Control unit 712 Operation panel 713 Temperature sensor 714 Humidity sensor 751 White ink usage determination unit 752 Setting information storage unit 753 Image forming position acquisition unit 754 Usage amount prediction unit 755 Mist generation amount prediction unit 756 Interval control unit 757 Holding unit Height variable section 758 Movable height variable section 1000 Image imparting system H Host M1 Main scanning motor M2 Sub-scanning motor M3 Stage lift motor M4 Image forming unit lift motor M Mist generation amount ΔW White ink usage amount α Coefficient according to interval β Coefficient depending on temperature and/or humidity γ Coefficient depending on image forming position

Patent No. 5024408 Patent No. 3552694 Japanese Patent Application Publication No. 2007-296754

Claims (6)

A liquid ejection device,
a liquid ejection head that ejects at least white liquid onto a recording medium;
a movable part that moves the liquid ejection head in a predetermined direction;
a holding unit that holds the recording medium;
a mechanism that changes the distance between the movable part and the holding part by changing the positions of the moving part and the holding part in the height direction;
The amount of white liquid used by the liquid ejection head, the distance between the movable part and the holding part, the image forming position on the mounting member on which the recording medium is placed, and the temperature or humidity of the liquid ejection device. a mist generation amount prediction unit that predicts the amount of mist generation based on at least one of the following;
The position of the holding portion or the movable portion is adjusted so that the distance between the liquid ejection head and the recording medium is narrower than a standard distance when the amount of mist generated by ejection of the white liquid is equal to or greater than a predetermined threshold. A liquid ejection device comprising: an interval control unit that changes the interval. The liquid ejection head includes:
Discharging the white liquid based on image data,
The liquid ejecting apparatus according to claim 1 , further comprising a usage amount prediction unit that predicts the usage amount of the white liquid based on image density information in the image data. The liquid ejection head includes:
Discharging the white liquid based on image data,
The liquid ejection apparatus according to claim 1 , further comprising a usage amount prediction unit that predicts the usage amount of the white liquid based on the ejection data obtained by quantizing the image data. The liquid ejection head includes:
Discharging the white liquid based on image data,
an image forming position acquisition unit that acquires the image forming position based on a distance between an edge of an image formed on the recording medium based on the image data and an outer circumference of a mounting member on which the recording medium is placed; The liquid ejection device according to any one of claims 1 to 3 . A liquid discharging method using a liquid discharging device, the method comprising:
ejecting at least a white liquid onto a recording medium by a liquid ejection head;
moving the liquid ejection head in a predetermined direction by a movable part;
holding the recording medium by a holding section;
changing the distance between the movable part and the holding part by changing the heightwise positions of the movable part and the holding part by a mechanism;
The mist generation amount prediction unit predicts the amount of white liquid used by the liquid ejection head, the distance between the movable part and the holding part, the image forming position on the mounting member on which the recording medium is placed, and the amount of white liquid used by the liquid ejection head. predicting the amount of mist generated based on at least one of the temperature or humidity of the discharge device;
The position of the holding portion or the movable portion is adjusted so that the distance between the liquid ejection head and the recording medium is narrower than a standard distance when the amount of mist generated by ejection of the white liquid is equal to or greater than a predetermined threshold. A liquid discharging method for performing the changing process. A program to be executed by a liquid ejection device,
The liquid ejection head ejects at least white liquid onto the recording medium;
moving the liquid ejection head in a predetermined direction by a movable part;
holding the recording medium by a holding unit;
A mechanism changes the distance between the movable part and the holding part by changing the positions of the moving part and the holding part in the height direction,
The mist generation amount prediction unit predicts the amount of white liquid used by the liquid ejection head, the distance between the movable part and the holding part, the image forming position on the mounting member on which the recording medium is placed, and the amount of white liquid used by the liquid ejection head. Predicting the amount of mist generated based on at least one of the temperature or humidity of the discharge device,
The position of the holding portion or the movable portion is adjusted so that the distance between the liquid ejection head and the recording medium is narrower than a standard distance when the amount of mist generated by ejection of the white liquid is equal to or greater than a predetermined threshold. A program that causes the liquid ejection device to execute a process for changing.

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