Maintenance device, liquid ejection device, maintenance method, and maintenance program

Abstract

To prevent inconvenience in which formation unevenness of a created object occurs before and after cleaning of a plurality of heads.SOLUTION: A maintenance device includes: a cleaning control part for controlling a cleaning part for cleaning a plurality of heads for discharging a liquid; a determination part for determining the timing for executing the cleaning of the heads; and a start interruption control part for controlling start and interruption of the creation of a created object performed by using a liquid. The start interruption control part performs interruption control of the creation of the created object, when the timing comes for executing the cleaning of the heads determined by the determination part, and when the cleaning of the heads is finished, it performs resumption control of the creation of the created object. Also, every time the timing comes for executing the cleaning of the heads and the interruption control is performed on the creation of the created object by the start interruption control part, the cleaning control part controls the cleaning part so as to clean one head out of the plurality of heads.SELECTED DRAWING: Figure 8

Description

Technical Field

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

Background Art

[0002] At present, an inkjet printer device equipped with a platen heater is known. In this inkjet printer device, the paper is heated by the platen heater, and the ink on the paper evaporates. As a result, dew condensation adheres to the nozzle surface of the recording head, and nozzles that are difficult to eject liquid correctly (nozzle clogging occurs). Therefore, during printing, the nozzle surface is regularly cleaned to prevent nozzle clogging due to dew condensation.

[0003] Patent Document 1 (Japanese Patent Application Laid-Open No. 2013-176900) discloses an inkjet recording device that achieves continuous recording stability and intermittent recording stability. This inkjet recording device has a first cleaning that ejects non-recording inkjet recording ink toward the ink receptor and cleans the nozzles and nozzle surface of the print head. Further, this inkjet recording device moves the print head to the ink receptor, and under the condition that the amount of non-recording ejection is less and the execution frequency is higher than that of the first cleaning, ejects non-recording inkjet recording ink from the print head toward the ink receptor and has a second cleaning that cleans the nozzles of the print head.

[0004] Then, the usage state and clogging state of the nozzles are detected, and the first cleaning and the second cleaning are appropriately used. Thereby, continuous recording stability and intermittent recording stability can be achieved.

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, in the case where Patent Document 1 and conventional inkjet recording apparatuses include a plurality of recording heads, dew condensation cleaning is sequentially performed for each recording head, and cleaning of all the recording heads is performed. Therefore, printing is interrupted until cleaning of all the recording heads is completed. While this printing is interrupted, there has been a problem in that uneven density of printed matter occurs before and after cleaning due to a change in the drying state of the ink on the platen heater.

[0006] The present invention has been made in view of the above problems, and an object thereof is to provide a maintenance apparatus, a liquid ejection apparatus, a maintenance method, and a maintenance program that prevent the inconvenience of uneven formation of a created object before and after cleaning of a plurality of heads.

Means for Solving the Problems

[0007] In order to solve the above-described problems and achieve the object, the present invention controls a cleaning unit that cleans a plurality of heads that eject liquid Then, the cleaning unit executes a first cleaning step and a second cleaning step with a higher degree of cleanliness than the first cleaning step by the cleaning unit a cleaning control unit that By the first cleaning step a determination unit that determines the timing And the timing for cleaning the head by the second cleaning step to execute cleaning of the heads, and a start / stop control unit that controls the start and stop of creation of a created object using the liquid. The start / stop control unit controls to interrupt the creation of the created object when the timing to execute cleaning of the heads, determined by the determination unit, is reached, and controls to resume the creation of the created object when the cleaning of the heads is completed. The cleaning control unit controls the cleaning unit to clean any one of the plurality of heads each time the timing to execute cleaning of the heads is reached and the creation of the created object is interrupted by the start / stop control unit Then, when the timing for executing the first cleaning step and the timing for executing the second cleaning step overlap, the second cleaning step is preferentially executed to do so.

Effects of the Invention

[0008] According to the present invention, there is an effect that it is possible to prevent the inconvenience of uneven formation of a created object before and after cleaning of a plurality of heads.

Brief Description of the Drawings

[0009]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Embodiments for Carrying Out the Invention

[0010] Hereinafter, with reference to the accompanying drawings, an inkjet printer apparatus (an example of a liquid ejection apparatus) according to an embodiment will be described. In the following description, the term "paper" is not limited to paper in terms of material, and includes OHP films (polyester films), cloth, glass, substrates, etc., and any material to which ink droplets and other liquids can adhere. Further, "paper" includes those referred to as a recording medium, a recording sheet, a recording paper, a recording sheet, etc. Also, image formation, recording, printing, imprinting, and printing are all synonymous terms.

[0011] Further, the "inkjet printer apparatus" may eject a liquid onto a medium such as paper, thread, fiber, fabric, leather, metal, plastic, glass, wood, ceramics, etc. to form an image. Also, "image formation" includes not only forming an image such as characters or figures on a medium, but also forming an image having no meaning such as a pattern on a medium (simply landing a liquid (droplet) on the medium).

[0012] Also, the term "ink" is used as a general term for all liquids capable of forming an image, not limited to what is specifically called ink, but also including recording liquids, fixing treatment liquids, liquids, etc. For example, "ink" includes DNA (Deoxyribonucleic Acid) samples, resists, pattern materials, resins, etc.

[0013] Also, "image" includes not only planar ones, but also three-dimensionally formed images or three-dimensional shaped objects.

[0014] [First Embodiment] (Mechanical Configuration) FIG. 1 is a perspective view of an inkjet printer apparatus according to a first embodiment. FIG. 2 is a diagram showing the configuration of a main part of the inkjet printer apparatus according to the first embodiment. As shown in FIGS. 1 and 2, an inkjet printer apparatus 100 according to the first embodiment is a serial type inkjet printer apparatus, and holds a carriage 3 movably by a main guide member 1 and a sub-guide member horizontally mounted on left and right side plates. Then, it reciprocates in the main scanning direction (carriage moving direction) via a timing belt 8 spanned between a driving pulley 6 and a driven pulley 7 by a main scanning motor 5.

[0015] The carriage 3 is provided with recording heads 4a and 4b each composed of a liquid ejection head (referred to as "recording head 4" when not distinguished). The recording head 4 ejects ink droplets of each color such as yellow (Y), cyan (C), magenta (M), and black (K), for example. Further, the recording head 4 is formed by arranging a plurality of nozzle rows composed of a plurality of nozzles in a plurality of columns in a sub-scanning direction orthogonal to the main scanning direction. Each nozzle is provided such that the droplet ejection direction is downward.

[0016] As shown in FIG. 3, for example, the recording head 4 has two nozzle rows Na and Nb each arranging a plurality of nozzles 4n. One nozzle row Na of the recording head 4a ejects black (K) liquid, and the other nozzle row Nb ejects cyan (C) liquid. One nozzle row Na of the recording head 4b ejects magenta (M) liquid, and the other nozzle row Nb ejects yellow (Y) liquid, respectively.

[0017] As the recording head 4, for example, 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 can be used.

[0018] On one hand, a transport mechanism 51 for transporting the paper 10 facing the recording head 4 includes a transport belt 12. This transport belt 12 is an endless belt and is stretched between a transport roller 13 and a tension roller 14. Then, the transport roller 13 is rotationally driven by a sub-scanning motor 16 via a timing belt 17 and a timing pulley 18, so that the transport belt 12 moves in a circular motion in the sub-scanning direction. This transport belt 12 is charged (electric charge is applied) by a charging roller (not shown) while moving in a circular motion.

[0019] Furthermore, on one side of the carriage 3 in the main scanning direction, a maintenance and recovery mechanism 20 for maintaining and recovering the recording head 4 is provided on the side of the transport belt 12, and on the other side, an empty discharge receiver 21 for receiving empty discharge droplets from the recording head 4 is provided on the side of the transport belt 12.

[0020] The maintenance and recovery mechanism 20 has, for example, a cap member 20a for capping the nozzle surface (the surface on which nozzles are formed) of the recording head 4, a wiper member 20b for wiping the nozzle surface, and an empty discharge receiver (not shown) for receiving a liquid that does not contribute to image formation.

[0021] The wiper member 20b is, as an example, a web wiping device, and is configured not to damage the nozzle surface even when cleaning is performed in a state where the nozzle surface is not wet with ink.

[0022] Also, an encoder scale 23 with a predetermined pattern is provided between both side plates along the main scanning direction of the carriage 3. Further, a main scanning encoder sensor 24 composed of a transmissive photosensor for reading the pattern of the encoder scale 23 is provided on the carriage 3. The encoder scale 23 and the main scanning encoder sensor 24 form a linear encoder (main scanning encoder) for detecting the movement of the carriage 3.

[0023] Further, a code wheel 25 is provided on the shaft of the conveyance roller 13. Also, a sub-scanning encoder sensor 26 composed of a transmissive photosensor for detecting a pattern formed on the code wheel 25 is provided. The code wheel 25 and the sub-scanning encoder sensor 26 form a rotary encoder (sub-scanning encoder) for detecting the movement amount and movement position of the conveyance belt 12.

[0024] In such an inkjet printer device, the sheet 10 fed from the paper feed tray is adsorbed onto the charged conveyance belt 12 and conveyed in the sub-scanning direction by the circumferential movement of the conveyance belt 12. The carriage 3 moves in the main scanning direction and drives the recording head 4 in accordance with the image signal. Thereby, ink droplets are ejected onto the conveyed and stopped sheet 10, and an image for one line or the like is recorded. After that, the sheet 10 is conveyed a predetermined amount in the sub-scanning direction, and recording for the next line is performed. By repeating such an operation, printing of an image is performed for each line on the sheet 10. The printed sheet 10 is discharged to the discharge tray.

[0025] (Electrical Configuration) FIG. 4 is a block diagram of the inkjet printer device 100. In FIG. 4, the control unit 500 includes a main control unit 500A including a CPU 501 that controls the entire inkjet printer device 100, a ROM 502 that stores programs executed by the CPU 501 and other fixed data, and a RAM 503 that temporarily stores image data and the like.

[0026] Further, the control unit 500 includes a host I / F 506 that mediates data transfer with a host device (information processing device) 600 such as a personal computer device (PC), an image output control unit 511 that drives and controls the recording head 4, and an encoder analysis unit 512. The encoder analysis unit 512 analyzes detection signals from the main scanning encoder sensor 24 and the sub-scanning encoder sensor 26.

[0027] In addition, the control unit 500 includes an I / O 516 between a main scanning motor drive unit 513 that drives the main scanning motor 5, a sub-scanning motor drive unit 514 that drives the sub-scanning motor 16, and various sensors and actuators 517.

[0028] The image output control unit 511 performs generation of print data, generation of drive waveforms for driving and controlling the recording head 4, selection of required drive signals from the drive waveforms, head control signals, transfer of print data, and the like. Then, it supplies drive waveforms, head control signals, print data, etc. to the head driver 510 for driving the recording head 4 provided on the carriage 3 side. As a result, a liquid corresponding to the print data is ejected from the nozzles of the recording head 4.

[0029] In addition, the encoder analysis unit 512 includes a direction detection unit 520 that detects the moving direction from the detection signal and a counter unit 521 that detects the moving amount.

[0030] Based on the analysis result from the encoder analysis unit 512, the control unit 500 controls the movement of the carriage 3 by driving and controlling the main scanning motor 5 via the main scanning motor drive unit 513. Also, it controls the feeding of the paper 10 by driving and controlling the sub-scanning motor 16 via the sub-scanning motor drive unit 514.

[0031] In addition, the control unit 500 has a suction drive unit 523 that controls the suction of a suction unit 524 that performs suction of the nozzles during cleaning of the recording head 4. The control unit 500 drives and controls the first to third heaters 3A, 3B, 3C, 3D, which will be described later with reference to FIG. 6, and has a heater control unit 531 that acquires temperature detection information indicating the current temperatures of the respective heaters 3A, 3B, 3C, 3D detected by the heater temperature sensor 525. Also, the control unit 500 has a wiper drive unit 532 that drives the wiper member 20b of the maintenance and recovery mechanism 20.

[0032] Further, the inkjet printer device 100 has a decap detection unit 526 that detects a decap state (= printing state) in which the recording head 4 is not covered by the cap member 20a (cover). Further, the control unit 500 has a timer 507 for counting the continuous time elapsed since the recording head 4 entered the decap state.

[0033] Further, a maintenance program for performing maintenance control (cleaning) of the recording head 4, which will be described later, is stored in the ROM 502 of the main control unit 500A. Also, the ROM 502 stores temperature coefficients determined based on the current temperatures of the heaters 3A, 3B, 3C, and 3D detected by the heater temperature sensor 525. Further, the inkjet printer device 100 of the first embodiment is provided with a first cleaning and a second cleaning, each having a different cleaning process, as types of cleaning of the recording head 4. Which of the first cleaning and the second cleaning is to be performed is determined according to the decap time of the recording head 4 calculated by multiplying the temperature coefficient. The ROM 502 stores a threshold value of this decap time and a cleaning threshold value for determining the cleaning process to be executed among the first cleaning and the second cleaning.

[0034] (Functional configuration) FIG. 5 is a functional block diagram of each function realized by the CPU 501 executing the maintenance program stored in the ROM 502. As shown in this FIG. 5, by executing the maintenance program, the CPU 501 functions as an activation timing counter unit 700, a first counter unit 701, a second counter unit 702, a third counter unit 703, a determination unit 704, a maintenance control unit 705, and a print control unit 706. Also, as will be described later, by executing the maintenance program, the CPU 501 also functions as a dew condensation amount determination unit 707.

[0035] The activation timing counter unit 700 counts a predetermined time, for example, three minutes, while printing is in progress, based on the timekeeping information counted by the timer 507 shown in FIG. 4. As will be described later, the maintenance control unit 705 executes and controls a predetermined cleaning process for a predetermined recording head every time the activation timing counter unit 700 counts "three minutes" while printing is in progress. That is, in this example, during printing, a predetermined cleaning process is performed on a predetermined recording head every three minutes. Note that the activation timing counter unit 700 may be provided in hardware.

[0036] The first counter unit 701 to the third counter unit 703 are examples based on the premise that the inkjet printer device 100 of the first embodiment is provided with a total of three recording heads 4, namely, the first to the third recording heads. That is, the number of counter units corresponding to the number of recording heads 4 is provided. In the case of this example, since there are three recording heads 4, namely, the first to the third recording heads, the first counter unit 701 to the third counter unit 703 are provided in software (each counter unit 701 to 703 may be provided in hardware).

[0037] The first counter unit 701 to the third counter unit 703 each have a counter unit for the first cleaning process and a counter unit for the second cleaning process inside.

[0038] The first counter unit 701 counts the time during which the first cleaning process has not been performed on the first recording head 4 by the counter unit for the first cleaning process. Also, the first counter unit 701 counts the time during which the second cleaning process has not been performed on the first recording head 4 by the counter unit for the second cleaning process. Further, the counter unit for the first cleaning process and the counter unit for the second cleaning process calculate the time obtained by multiplying each counted time during which the first or second cleaning process has not been performed by a predetermined coefficient such as a temperature coefficient described later. Then, the time that is the calculation result obtained by sequentially adding the times obtained by multiplying each by the predetermined coefficient is calculated as the time during which the first cleaning has not been performed on the first recording head 4 and the time during which the first cleaning has not been performed. The second counter unit 702 calculates, by the same calculation, the times during which the first and second cleanings have not been performed on the second recording head 4, respectively. Similarly, the third counter unit 703 calculates the times during which the first and second cleanings have not been performed on the third recording head 4, respectively.

[0039] The determination unit 704 compares the "time during which the first cleaning has not been performed" calculated by each of the first counter unit 701 to the third counter unit 703 with the threshold value for the first cleaning every time, for example, "3 minutes" is counted by the activation timing counter unit 700. Also, it compares the "time during which the second cleaning has not been performed" calculated by each of the first counter unit 701 to the third counter unit 703 with the threshold value for the second cleaning.

[0040] In one example, the threshold for the first cleaning is, for example, "9 minutes". Also, the threshold for the second cleaning is, for example, "18 minutes". The determination unit 704 determines whether each recording head 4 has elapsed the threshold of 9 minutes without the first cleaning being performed. Further, the determination unit 704 determines whether each recording head 4 has elapsed the threshold of 18 minutes without the second cleaning being performed. The determination unit 704 supplies such determination results to the maintenance control unit 705.

[0041] The maintenance control unit 705 is an example of a cleaning control unit. The maintenance control unit 705 controls the wiper member 20b, the suction unit 524, etc. to perform the first cleaning or the second cleaning on one recording head for which it has been determined that a time equal to or greater than the threshold has elapsed. The print control unit 706 is an example of a start interruption control unit and performs print control such as interruption control and restart control of the print operation during cleaning of the recording head 4.

[0042] Note that, as will be described later, the dew condensation amount determination unit 707 predicts the dew condensation amount of the recording head 4 based on various factors. Each of the counter units 701 to 703 multiplies the counted cap time by a coefficient corresponding to the dew condensation amount predicted by the above-described temperature coefficient and dew condensation amount determination unit 707 to calculate the "time during which the first and second cleanings have not been performed" for each recording head 4.

[0043] Also, the first counter units 701 to the dew condensation amount determination unit 707 of the inkjet printer device 100 shown in FIG. 5 are each to be realized by software by a maintenance program. However, all or part of these may be realized by hardware such as an IC (Integrated Circuit).

[0044] In addition, the maintenance program may be provided by being recorded on a computer-readable recording medium such as a CD-ROM or a flexible disk (FD) in the form of installable or executable file information. Further, the maintenance program may be provided by being recorded on a computer-readable recording medium such as a CD-R, a DVD (Digital Versatile Disk), a Blu-ray (registered trademark) disk, or a semiconductor memory. Further, the maintenance program may be provided in a form that can be installed via a network such as the Internet. Further, the maintenance program may be provided by being pre-installed in a ROM or the like in the device.

[0045] (Condensation on the nozzle surface) FIG. 6 is a diagram for explaining condensation generated on the nozzle surface of the recording head 4 in the inkjet printer apparatus 100 according to the first embodiment. As shown in this FIG. 6, in the case of the inkjet printer apparatus 100 according to the first embodiment, in order to promote drying of the ink on the paper 10, the first to third platen heaters 3A to 3C and the fan heater 3D are used.

[0046] The ink ejected from the nozzles of the recording head 4 lands on the conveyed paper 10 and is dried by the heat of the platen heaters 3A to 3C. The ink vapor generated in this drying process condenses on the nozzle surface of the recording head 4. If printing continues, the amount of condensation on this nozzle surface increases, and finally, due to this condensation, ejection failure occurs in the recording head 4. In order to prevent such ejection failure, it is necessary to periodically remove this condensation during printing.

[0047] (Types of cleaning processes) The inkjet printer apparatus 100 according to the first embodiment has two types of cleaning processes as the cleaning process of the recording head 4. FIGS. 9(a) to 9(c) show the first cleaning process. FIGS. 10(a) to 10(d) show the second cleaning process.

[0048] The first cleaning process has a "wiping process" of wiping the recording head 4 with dew adhered thereto with a wiper member 20b as shown in FIG. 9(b). Further, the first cleaning process has an "ink ejection process" of ejecting ink onto a cap member 20a or a dedicated ink receiver or the like by operating each nozzle with the recording head 4 from which dew has been wiped off by wiping as shown in FIG. 9(c).

[0049] When the first cleaning process is selected, such a "wiping process" and "ink ejection process" are successively applied to the recording head 4. In this first cleaning process, a "head suction process" performed in a second cleaning process described below is omitted. Therefore, the first cleaning process can be carried out in a shorter time than the second cleaning process.

[0050] On the other hand, the second cleaning process has a "head suction process" of sucking and cleaning each nozzle of the recording head 4 with dew adhered thereto as shown in FIG. 10(a) and wiping the recording head 4 with a wiper member 20b as shown in FIG. 10(b). Further, the second cleaning process has a "wiping process" of wiping the recording head 4 from which dew has been wiped off by wiping with a wiper member 20b and an "ink ejection process" of ejecting ink onto a cap member 20a or a dedicated ink receiver or the like by operating each nozzle as shown in FIG. 10(d).

[0051] When the second cleaning process is selected, such a "head suction process", "wiping process" and "ink ejection process" are successively applied to the recording head 4. Since the "head suction process" is carried out in this second cleaning process, it takes a little more time than the first cleaning process, but the dew can be cleaned with a higher degree of cleanliness than the first cleaning process.

[0052] (Determination operation of cleaning timing) Next, the conditions for cleaning the recording head during printing will be described. The amount of dew condensation adhering to the nozzle surface of the recording head 4 increases as the ink ejection time (printing time) becomes longer. Also, the amount of dew condensation increases as the difference between the temperatures of the heaters 3A to 3D and the head temperature of the recording head 4 becomes larger. From these facts, the counter parts for the first cleaning process and the counter parts for the second cleaning process of the first counter part 701 to the third counter part 703 calculate the "time when the first cleaning has not been performed" and the "time when the second cleaning has not been performed" for each recording head 4 using the following mathematical formula. Hereinafter, the time when these two cleanings have not been performed may be collectively referred to as the "time when cleaning has not been performed".

[0053] Time when cleaning has not been performed (seconds) = Σ (temperature coefficient × decap time (seconds))

[0054] The decap time is the time elapsed continuously since the cap member 20a for preventing drying, which covers the recording head 4 during non-recording, has been removed. That is, the decap time is the time elapsed continuously since printing was started. The decap detection unit 526 shown in FIG. 4 detects the decap state of the recording head 4 and notifies the CPU 501. The CPU 501 (the first counter part 701 to the third counter part 703) starts counting the timing information from the timer 507 at the timing when the decap state of the recording head 4 is notified.

[0055] The temperature coefficient is determined based on the heater temperature detected by the heater temperature sensor 525 and the head temperature detected by the head temperature detection unit 527 as shown in the temperature table of Table 1 below. The larger the temperature difference between the heaters 3A to 3D and the recording head 4, the larger the value of the temperature coefficient. The magnitude relationship of the temperature coefficients shown in this Table 1 is "E" < "D" < "C" < "B" < "A", where the temperature coefficient of "E" is the smallest value and the temperature coefficient of "A" is the largest value.

[0056]

Table 1

[0057] The CPU 501 calculates the "time when the first cleaning has not been performed" and the "time when the second cleaning has not been performed" for each recording head 4 through an operation of multiplying and adding the temperature coefficient set based on the heater temperature and the head temperature to the decapping time of each recording head 4. Then, the first cleaning process is performed on the recording head 4 for which this "time when cleaning has not been performed" is equal to or greater than the first cleaning threshold value. Also, the second cleaning process is performed on the recording head 4 for which the "time when cleaning has not been performed" is equal to or greater than the second cleaning threshold value.

[0058] Also, the greater the difference between the temperatures of the heaters 3A to 3D and the head temperature of the recording head 4, the greater the amount of condensation. As shown in Table 1, the greater the difference between the temperatures of the heaters 3A to 3D and the head temperature of the recording head 4, the greater the temperature coefficient value used in the above operation. As a result, the greater the difference between the temperatures of the heaters 3A to 3D and the head temperature of the recording head 4, the greater the value of the "time when cleaning has not been performed" calculated, and the faster it reaches the above-described first or second cleaning threshold value, so that the cleaning of the condensation on the recording head 4 is frequently performed.

[0059] (Timing of Cleaning of Each Recording Head Based on Temperature Coefficient) FIG. 7 is a diagram showing the timing of cleaning of each recording head based on the temperature coefficient. FIG. 7(a) shows the transition of the temperature coefficient based on the changes in the heater temperature and the head temperature. FIG. 7(b) shows the cleaning interval (cleaning timing) of each recording head.

[0060] In FIGS. 7(a) and 7(b), assuming that based on the detection results of the heater temperature and the head temperature at the start of printing, the difference between the heater temperature and the head temperature is large and the temperature coefficient is determined to be the temperature coefficient of "A" in Table 1. In this case, by multiplying a large value of the temperature coefficient by the "time when cleaning has not been performed" for each recording head, the "time when cleaning has not been performed" for each recording head reaches the above-mentioned first cleaning threshold value, etc., earlier. For this reason, cleaning for each recording head 4 is also performed at short intervals.

[0061] Next, when printing continues and for example the head temperature rises, the temperature coefficient used gradually changes to a smaller value in the order of, for example, "A" → "B" → "C". When the temperature coefficient changes to "B", by multiplying the temperature coefficient of "B", which is a smaller value than "A", the interval for cleaning each recording head becomes longer than when using the temperature coefficient of "A". Similarly, when the temperature coefficient changes to "C", by multiplying the temperature coefficient of "C", which is an even smaller value than "B", the interval for cleaning each recording head becomes even longer than when using the temperature coefficient of "B".

[0062] Note that the switching of the temperature coefficient is performed when the cleaning of all the recording heads 4 based on that temperature coefficient is completed. For example, the switching from the temperature coefficient "A" to the temperature coefficient "B" is performed after the cleaning of the first to third recording heads is completed with the temperature coefficient "A", as shown in FIG. 7(b). Similarly, the switching from the temperature coefficient "B" to the temperature coefficient "C" is performed after the cleaning of the first to third recording heads is completed with the temperature coefficient "B", as shown in FIG. 7(b).

[0063] (Selection operation of the recording head to perform cleaning) Here, the inkjet printer device 100 of the first embodiment does not perform the cleaning operations of the plurality of recording heads 4 during printing simultaneously (performs them with a time difference), so that the time required for one cleaning is shortened and the occurrence of density unevenness in the printed matter is suppressed.

[0064] Therefore, the inkjet printer apparatus 100 according to the first embodiment performs cleaning of the recording head 4 one by one in the order in which "the time without cleaning (temperature coefficient × decapping time (seconds))" reaches the threshold value, and does not clean the plurality of recording heads 4 simultaneously. Further, when the dew condensation amounts of the plurality of recording heads 4 reach the threshold value simultaneously, the cleaning of the recording head 4 is performed one by one according to the priority order of each recording head 4 determined in advance as shown in Table 2 below.

[0065] [Table 2]

[0066] This example of Table 2 shows the priority order of each recording head and each cleaning process. In the second cleaning process, a "head suction process" that is not present in the first cleaning process is performed. For this reason, it is a cleaning process with a higher cleaning degree than the first cleaning process. This example of Table 2 shows that the second cleaning process is preferentially performed over the first cleaning process (first cleaning process < second cleaning process). Further, this Table 2 shows that the priority order of each recording head is in the order of the first recording head > the second recording head > the third recording head.

[0067] Therefore, any cleaning process is performed on each recording head in the order of the second cleaning process for the first recording head > the second cleaning process for the second recording head > the second cleaning process for the third recording head > the first cleaning process for the first recording head > the first cleaning process for the second recording head > the first cleaning process for the third recording head.

[0068] Next, the maintenance control unit 705 shown in FIG. 5 1. Performs cleaning of the recording head 4 with a count value exceeding the threshold value 2. When there is no recording head 4 with a count value exceeding the threshold, clean the recording head 4 with the count value closest to the threshold. 3. When there are multiple recording heads 4 with count values exceeding the threshold, or when there is no recording head 4 with a count value exceeding the threshold and there are multiple recording heads 4 with count values closest to the threshold, in either case, perform the cleaning according to the priority order determined in advance for each type of cleaning (the first or second cleaning) (priority order for each cleaning type). 4. When there are multiple recording heads 4 corresponding to the count values applicable up to "3", perform cleaning on the recording head 4 with the largest count value. 5. When there are multiple recording heads 4 corresponding to the count values applicable up to "4", perform cleaning according to the priority order of the recording heads 4 (priority order for each recording head).

[0069] To explain with an example, for instance, assume that three recording heads 4 are provided and two types of cleaning, namely the first cleaning and the second cleaning, are provided. Also, assume that the priority order of each recording head 4 is set in the order of "the first recording head > the second recording head > the third recording head", and the priority order of the cleaning types is set in the order of "the second cleaning > the first cleaning".

[0070] In addition, as the thresholds for selecting the cleaning types, there are provided a first cleaning threshold (the first threshold) for determining whether to perform the first cleaning process described with reference to FIG. 9, and a second cleaning threshold (the second threshold) for determining whether to perform the second cleaning process described with reference to FIG. 10.

[0071] The determination of whether to perform cleaning and the execution of cleaning are carried out by the activation timing counter unit 700 shown in FIG. 5, for example, every time "3 minutes" is counted. The arrow separations shown in FIG. 8(a) indicate this 3-minute separation. That is, in the activation timing counter unit 700, for example, every time "3 minutes" is counted, the determination of whether to perform cleaning and the execution of cleaning are carried out.

[0072] Specifically, when 3 minutes have elapsed in the activation timing counter unit 700 since the start of printing, the determination unit 704 shown in FIG. 5 determines whether the "time when the first cleaning has not been performed" calculated by the counter unit for the first cleaning process of the first counter unit 701 for the first recording head is a value equal to or greater than the first threshold value for the first cleaning. And when it is determined that the calculated "time when the first cleaning has not been performed" is a time equal to or greater than the first threshold value for the first cleaning, the maintenance control unit 705 controls each unit to perform the first cleaning on the first recording head 4 as shown in FIG. 8(b).

[0073] Next, when another 3 minutes have elapsed in the activation timing counter unit 700, the determination unit 704 determines whether the "time when the first cleaning has not been performed" calculated by the counter unit for the first cleaning process of the second counter unit 702 for the second recording head is a value equal to or greater than the first threshold value for the first cleaning. And when it is determined that the calculated "time when the first cleaning has not been performed" is a value equal to or greater than the first threshold value for the first cleaning, the maintenance control unit 705 controls each unit to perform the first cleaning on the second recording head 4 as shown in FIG. 8(c).

[0074] Next, when the activation timing counter unit 700 further counts the elapse of 3 minutes, the determination unit 704 determines whether the "time when the first cleaning has not been performed" calculated by the counter unit for the first cleaning process of the third counter unit 703 for the third recording head is equal to or greater than the first threshold value for the first cleaning. When it is determined that the calculated "time when the first cleaning has not been performed" is equal to or greater than the first threshold value for the first cleaning, the maintenance control unit 705 controls each unit to perform the first cleaning on the third recording head 4 as shown in FIG. 8(d).

[0075] Next, when the activation timing counter unit 700 further counts the elapse of 3 minutes, the determination unit 704 determines whether the "time when the second cleaning has not been performed" calculated by the counter unit for the second cleaning process of the first counter unit 701 for the first recording head is equal to or greater than the second threshold value for the second cleaning. When it is determined that the calculated "time when the second cleaning has not been performed" is equal to or greater than the second threshold value for the second cleaning, the maintenance control unit 705 controls each unit to perform the second cleaning on the first recording head 4 as shown in FIG. 8(e).

[0076] Next, when the activation timing counter unit 700 further counts the elapse of 3 minutes, the determination unit 704 determines whether the "time when the second cleaning has not been performed" calculated by the counter unit for the second cleaning process of the second counter unit 702 for the second recording head is equal to or greater than the second threshold value for the second cleaning. When it is determined that the calculated "time when the second cleaning has not been performed" is equal to or greater than the second threshold value for the second cleaning, the maintenance control unit 705 controls each unit to perform the second cleaning on the second recording head 4 as shown in FIG. 8(f).

[0077] Next, when the activation timing counter unit 700 further counts the elapse of another 3 minutes, the determination unit 704 determines whether the "time when the second cleaning has not been performed" calculated by the counter unit for the second cleaning process of the third counter unit 703 for the third recording head is equal to or greater than the second threshold value for the second cleaning. When it is determined that the calculated "time when the second cleaning has not been performed" is equal to or greater than the second threshold value for the second cleaning, the maintenance control unit 705 controls each unit to perform the second cleaning on the third recording head 4 as shown in Fig. 8(g).

[0078] When the cleaning is completed, the counter units for the first cleaning process and the counter units for the second cleaning process of each of the counter units 701 to 703 reset the counter values.

[0079] Note that even when cleaning is performed by an arbitrary operation of the user or the like, the counter units for the first cleaning process and the counter units for the second cleaning process reset the counter values. Also, since the second cleaning process corresponds to a higher-level maintenance than the first cleaning process, when the second cleaning process is performed, both the counter unit for the first cleaning process and the counter unit for the second cleaning process reset the counter values.

[0080] In addition, when either the first cleaning process or the second cleaning process is performed, the activation timing counter unit 700 resets the count value. As a result, as shown in Fig. 8(a), for example, every 3 minutes, the recording head to be subjected to the cleaning process is determined and the cleaning is performed.

[0081] Furthermore, by arbitrarily changing the first threshold value for the first cleaning and the second threshold value for the second cleaning, the intervals and order of the first cleaning and the second cleaning can be changed. For example, it is also possible to perform the second cleaning after performing the first cleaning twice.

[0082] (Cleaning operation) Next, using the flowchart of FIG. 11, the flow of the cleaning operation of each recording head 4 in the inkjet printer apparatus 100 according to the first embodiment will be described. First, when printing is started, the heater temperature sensor 525 shown in FIG. 4 detects the temperatures of the heaters 3A to 3D, and the head temperature detection unit 527 detects the temperatures of the recording heads 4 (step S1). Note that the heater temperature sensor 525 may detect only the temperature of the second heater 3B that mainly heats the paper 10 for the purpose of evaporating the moisture of the ink.

[0083] The determination unit 704 determines the temperature coefficient as described with reference to Table 1 based on the temperature differences between the temperatures of the heaters 3A to 3D and the temperatures of the recording heads 4 (step S2). The activation timing counter unit 700 starts counting the elapsed time with the start of printing as a trigger (step S3).

[0084] Next, the activation timing counter unit 700 determines whether or not the counted elapsed time has exceeded a predetermined threshold value such as "3 minutes" (step S4). Until it is determined by the activation timing counter unit 700 that the elapsed time has exceeded the predetermined threshold value (step S4: No), the process of step S4 is repeatedly executed via step S5 for determining whether or not printing has ended.

[0085] When the activation timing counter unit 700 determines that the elapsed time has exceeded a predetermined threshold, it resets the count value and starts counting the elapsed time again. When it is determined that the elapsed time has exceeded the predetermined threshold, a cleaning process is performed as described below. Therefore, for example, if a threshold of "3 minutes" is set, the cleaning process described below is performed every 3 minutes.

[0086] Next, when the activation timing counter unit 700 determines that the elapsed time has exceeded a predetermined threshold (step S4: Yes), the process proceeds to step S6. The determination unit 704 refers to the counter values of the counter units for the first to third cleaning processes of the first to third counter units 701 to 703 for the first to third recording heads. Then, the determination unit 704 determines the presence or absence of a counter unit for the first cleaning process that exceeds the first threshold for the first cleaning and a counter unit for the second cleaning process that exceeds the second threshold for the second cleaning (step S6).

[0087] If there are a counter unit for the first cleaning process that exceeds the first threshold for the first cleaning and a counter unit for the second cleaning process that exceeds the second threshold for the second cleaning (step S6: Yes), the process proceeds to step S11. In step S11, the determination unit 704 determines whether there are multiple counter units for the first cleaning process that exceed the first threshold or the second threshold, or counter units for the second cleaning process (step S11).

[0088] If there is only one counter unit for the first cleaning process or the counter unit for the second cleaning process that exceeds the first threshold or the second threshold (step S11: No), the process proceeds to step S13. In step S13, the maintenance control unit 705 controls each unit to perform the first cleaning process on the recording head 4 corresponding to the counter unit for the first cleaning process that exceeds the first threshold. Or, the maintenance control unit 705 controls each unit to perform the second cleaning process on the recording head 4 corresponding to the counter unit for the second cleaning process that exceeds the second threshold. Thereby, the process proceeds to step S9.

[0089] On the other hand, if in step S11, the determination unit 704 determines that there are a plurality of counter units for the first cleaning process or the counter units for the second cleaning process that exceed the first threshold or the second threshold (step S11: Yes), the process proceeds to step S12. In step S12, the maintenance control unit 705 controls each unit to perform the first or second cleaning process on the recording head corresponding to the predetermined priority among the recording heads of the plurality of counter units that exceed the first threshold or the second threshold.

[0090] Specifically explaining the priority order, as described above, the second cleaning process is a higher-level maintenance than the first cleaning process. Also, the fact that the second cleaning process is required (= the second threshold is exceeded) means that it is necessary to perform the cleaning process on that recording head earlier. Therefore, in the case of the inkjet printer device of the first embodiment, as the "priority order for each cleaning type", the second cleaning process has a higher priority than the first cleaning process.

[0091] For this reason, the maintenance control unit 705 preferentially selects a recording head that performs the second cleaning process from among the plurality of recording heads corresponding to the counter units, and performs the second cleaning process. As a result, the process proceeds to step S9.

[0092] Note that, among the plurality of recording heads, cleaning may be performed on the recording head 4 with the largest count value, or cleaning may be performed according to the priority order for each recording head 4 as shown in Table 2.

[0093] On the other hand, in step S6, when it is determined that there is no counter unit for the first cleaning process that exceeds the first threshold value or the second threshold value, or there is no counter unit for the second cleaning process (step S6: No), the process proceeds to step S7. In step S7, the maintenance control unit 705 determines whether there are a plurality of counter units closest to the threshold value. When there are a plurality of counter units closest to the threshold value (step S7: Yes), the process proceeds to step S12 described above. On the contrary, when there is one counter unit closest to the threshold value (step S7: No), the process proceeds to step S8. In step S8, the maintenance control unit 705 performs the first or second cleaning process on the recording head corresponding to the counter unit that counts the counter value closest to the first threshold value or the second threshold value. As a result, the process proceeds to step S9.

[0094] When the cleaning process is performed on one recording head selected in this way, the count value of the counter unit for the first cleaning process or the counter unit for the second cleaning process corresponding to the recording head on which the cleaning process has been performed is reset (step S9).

[0095] Note that when the second cleaning corresponding to the upper-level maintenance is performed, the count value of the counter unit for the second cleaning process corresponding to the recording head on which the second cleaning has been performed is reset, and the count value of the counter unit for the first cleaning process is also reset.

[0096] When the count value of the counter unit is reset in step S9, the print control unit 706 resumes printing (step S10), and the process returns to step S1.

[0097] (Effect of the First Embodiment) As is clear from the above description, the inkjet printer device 100 of the first embodiment limits the number of heads to be cleaned in one cleaning to one, and only cleans one recording head. As a result, the time required for one cleaning can be suppressed to the minimum for one recording head. Therefore, it is possible to prevent the inconvenience that the drying state of each recording head 4 changes before and after cleaning and density unevenness occurs in the printed matter due to the long time required until the cleaning of all the recording heads 4 is completed.

[0098] [Second Embodiment] Next, an inkjet printer device according to a second embodiment will be described. Since the cause of condensation of the recording head 4 is due to ink vapor, the amount of condensation tends to increase as the printing rate (ink ejection amount, number of scans, etc.) increases. Therefore, considering the printing conditions (number of scans), the above-mentioned "time (seconds) without cleaning" may be calculated using the following formula.

[0099] Time (seconds) without cleaning = Σ (temperature coefficient × scan number coefficient × decapping time (seconds))

[0100] An example of the scan coefficient is shown in Table 3 below.

[0101] [Table 3]

[0102] As shown in Table 3, the scan number coefficient changes according to the number of printing passes. In this case, the larger the scan number, the larger the coefficient, and the earlier the cleaning timing becomes. Conversely, when the scan number decreases, the cleaning timing becomes later. Since the scan number does not change during printing, the scan number coefficient is determined at the start of printing or between pages.

[0103] In this way, by counting the de-capping time taking into account the scan number coefficient as well, a count value that more accurately represents the amount of condensation on the recording head 4 can be calculated. Therefore, the first cleaning and the second cleaning can be carried out at more optimal timings, and the same effects as those of the above-described first embodiment can be obtained.

[0104] [Third Embodiment] Next, an inkjet printer apparatus according to the third embodiment will be described. Condensation adhering to the nozzle surface is generated by the vapor of the ink, and thus time, temperature, and humidity have a great influence. For this reason, the inkjet printer apparatus according to the third embodiment has a condensation amount determination unit 707 shown in FIG. 5.

[0105] The condensation amount determination unit 707 counts the time information of the timer 507 and predicts the condensation amount based on the counted time. Further, the condensation amount determination unit 707 predicts the condensation amount based on the detection outputs of temperature and humidity from the temperature detection unit and the humidity detection unit shown as various sensors / actuators 517 in FIG. 4. Specifically, regarding temperature, there are the heater temperature, the head temperature, the temperature inside the machine, and the like. In particular, the heater temperature and the head temperature are highly sensitive, and the higher the heater temperature and the lower the head temperature, the larger the amount of condensation. Also, the higher the printing rate, the more the vapor of the ink becomes. For this reason, the condensation amount determination unit 707 also predicts the condensation amount from the ink ejection amount or the scan number of the carriage, etc.

[0106] The determination unit 704 calculates the "time (seconds) without cleaning" described above by multiplying the dew condensation amount prediction coefficient corresponding to the dew condensation amount predicted by the dew condensation amount determination unit 707 by the count values counted by the counter units for the first cleaning process provided in the first counter unit 701 to the third counter unit 703 respectively, and the count value counted by the counter unit for the second cleaning process, and then performing an integration process.

[0107] Time (seconds) without cleaning = Σ (temperature coefficient × scan number coefficient × dew condensation amount prediction coefficient × decapping time (seconds))

[0108] In this way, by taking into account the predicted dew condensation amount in the selection of the recording head 4 that performs cleaning, the first cleaning and the second cleaning can be performed at more optimal timings, and the same effects as those of the above-described embodiments can be obtained.

[0109] Note that the dew condensation amount determination unit 707 may predict the dew condensation amount in consideration of the type of medium (printing object) selected by the user, or may predict the dew condensation amount according to the distance between the recording head 4 and the medium detected by the gap detection unit. The dew condensation amount determination unit 707 may directly predict (determine) the dew condensation amount based on the captured image of the nozzle surface captured using the camera device. Also, the dew condensation amount determination unit 707 may predict (determine) the dew condensation amount based on the measurement result of the reflected light obtained by irradiating the nozzle surface with light. In any case, the same effects as those described above can be obtained.

[0110] Finally, the above-described embodiments are presented as examples and are not intended to limit the scope of the present invention. Each of these novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can also be made without departing from the gist of the invention.

[0111] For example, the above-described embodiment was an example in which the present invention was applied to an inkjet printer device that forms a printed matter by ejecting ink onto a recording medium. However, the present invention may also be applied to a three-dimensional modeling device that forms a three-dimensional object by ejecting a curing liquid onto stacked powders and curing them. In this case, by applying the present invention during cleaning of a plurality of ejection heads that eject the curing liquid onto the powders, the same effects as described above can be obtained.

[0112] Such embodiments and modifications of the embodiments are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalent scope thereof.

Explanation of Reference Numerals

[0113] 3 carriage 3A First heater 3B Second heater 3C Third heater 3D Fan heater 4 recording head 4n nozzle 10 paper 20 Maintenance and recovery mechanism 20b Wiper member 100 Inkjet printer device 507 Timer 510 Head driver 523 Suction drive unit 524 Suction unit 525 Heater temperature sensor 526 Decap detection unit 527 Head temperature detection unit 701 First counter unit 702 Second counter unit 703 Third counter unit 704 Judgment unit 705 Maintenance control unit 706 Printing control unit 707 Dew condensation amount judgment unit Na Nozzle row Nb Nozzle row

Prior Art Documents

Patent Document

[0114]

Patent Document 1

Claims

1. A cleaning control unit that controls a cleaning unit for cleaning a plurality of heads that discharge liquid, and executes a first cleaning step by the cleaning unit and a second cleaning step by the cleaning unit that has a higher degree of cleanliness than the first cleaning step; A determination unit that determines the timing of cleaning the head by the first cleaning step and the timing of cleaning the head by the second cleaning step; An start / stop control unit that controls the start and stop of creating an object using the liquid; and When the timing of cleaning the head, which is determined by the determination unit, is reached, the start / stop control unit controls to interrupt the creation of the object, and when the cleaning of the head is completed, the start / stop control unit controls to resume the creation of the object. When the timing of cleaning the head is reached and each time the creation of the object is interrupted by the start / stop control unit, the cleaning control unit controls the cleaning unit to clean any one of the plurality of heads, and when the timing of executing the first cleaning step and the timing of executing the second cleaning step overlap, the second cleaning step is preferentially executed. A maintenance device characterized by the above.

2. The determination unit determines the timing of cleaning the head based on the decap time, which is the time elapsed continuously after the head is uncovered by the covering member during the creation of the object. The maintenance device according to claim 1, characterized by the above.

3. The determination unit determines the timing of cleaning the head in consideration of the decap time, taking into account the temperature of a heater unit that heats the liquid discharged onto the object and the temperature coefficient determined based on the temperature difference of the head. The maintenance device according to claim 2, characterized by the above.

4. The determination unit determines the timing of cleaning the head in consideration of the decap time, taking into account at least the amount of dew condensation on the head predicted from the continuous creation time of the object, together with the temperature coefficient. The maintenance device according to claim 3, characterized by the above.

5. The determination unit determines a head for performing cleaning in accordance with the priority order set for each of the heads The maintenance device according to any one of claims 1 to 4, characterized in that

6. A creation unit that creates a creation using a liquid, The maintenance device according to any one of claims 1 to 5, A liquid ejection device having

7. A cleaning step in which a cleaning control unit controls a cleaning unit that cleans a plurality of heads that eject liquid, and the cleaning unit performs a first cleaning step and a second cleaning step that has a higher degree of cleanliness than the first cleaning step; A determination step in which a determination unit determines the timing for cleaning the head by the first cleaning step and the timing for cleaning the head by the second cleaning step; An start interruption control step in which an start interruption control unit controls the start and interruption of the creation of a creation performed using the liquid, In the start interruption control step, when the timing for cleaning the head, which is determined by the determination unit, is reached, the start interruption control unit controls the interruption of the creation of the creation, and when the cleaning of the head is completed, the start interruption control unit controls the resumption of the creation of the creation, In the cleaning step, when the timing for cleaning the head is reached and the creation of the creation is interrupted by the start interruption control unit each time, the cleaning control unit controls the cleaning unit to clean any one of the plurality of heads, and when the timing for performing the first cleaning step and the timing for performing the second cleaning step overlap, the second cleaning step is preferentially executed A maintenance method characterized by that

8. A computer, A cleaning control unit that controls a cleaning unit that cleans a plurality of heads that eject liquid, and the cleaning unit performs a first cleaning step and a second cleaning step that has a higher degree of cleanliness than the first cleaning step, A determination unit that determines the timing for cleaning the head by the first cleaning step and the timing for cleaning the head by the second cleaning step; Function as a start / stop control unit that controls the start and stop of creating a created object using the liquid; When the timing for cleaning the head, which is determined by the determination unit, is reached, the start / stop control unit controls to interrupt the creation of the created object, and when the cleaning of the head is completed, the start / stop control unit controls to resume the creation of the created object; When the timing for cleaning the head is reached and each time the creation of the created object is interrupted by the start / stop control unit, the cleaning control unit controls the cleaning unit to clean any one of the plurality of heads. When the timing for executing the first cleaning step overlaps with the timing for executing the second cleaning step, the second cleaning step is preferentially executed; A maintenance program characterized by the above.

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