JP2013203017A - Inkjet recording apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an inkjet recording apparatus capable of suppressing a difference in each area of a recording head smaller, in the amount of moisture supplied to the circumference of the recording head.SOLUTION: An inkjet recording apparatus includes a recording head 2 in which a plurality of discharge ports for discharging an ink are formed and performs recording by discharging the ink to a recording medium supported by a support surface 36 from the discharge port. An ink receiver 33 is provided in the support surface 36, wherein the ink receiver 33 is capable of storing the ink to supply moisture to the circumference of a part discharge port of the discharge ports formed in the recording head 2, in such a manner that the ink stored inside evaporates.

Description

  The present invention relates to an ink jet recording apparatus in which drying of ink around an ejection port is suppressed over the entire recording head.

  As a recording apparatus, an ink jet recording apparatus that performs recording by ejecting ink droplets from ejection ports formed in a recording head is often employed. In a recording head in an ink jet recording apparatus, ink thickening may occur due to evaporation of moisture in the ink from the ejection port. As the viscosity of the ink around the ejection port increases, the ink ejection amount may change or the ink landing accuracy may decrease. In addition, when the viscosity of the ink around the ejection port further increases, ink droplets may not be ejected from the ejection port even when the recording element is driven.

  In view of this, an example of a method for suppressing the drying of the ink around the ejection port in the recording head is disclosed in Patent Document 1. Patent Document 1 discloses an ink jet recording apparatus that has a steam generating means and supplies the steam generated by the steam generating means to the periphery of the recording head.

JP 2000-255053 A

  When steam is supplied to the periphery of the recording head, the humidity at that portion increases, and the recording medium may adsorb moisture from the surroundings while the recording medium is transported through a position corresponding to the recording head. is there. When the recording medium adsorbs a large amount of moisture, the recording medium subsequently passes through a position corresponding to the recording head in a state of containing much moisture. Therefore, in the area where the recording medium passes, more water is supplied to the recording head corresponding to the area.

  On the other hand, however, moisture is not supplied from the recording medium in an area located outside the area through which the recording medium passes in the recording head. For this reason, the amount of water supplied differs from region to region around the recording head, and water is sufficiently supplied in some regions, but there is a case where water supply is insufficient in some regions. there is a possibility. In such a case, there is a possibility that the ink around the ejection port in the recording head thickens in an area where the water supply is not sufficient, and that the ink ejection amount changes or the ink landing accuracy decreases. is there. In some cases, ink droplets may not be ejected from the ejection port.

  SUMMARY OF THE INVENTION In view of the above circumstances, an object of the present invention is to provide an ink jet recording apparatus capable of suppressing a difference in the amount of water supplied to the periphery of a recording head for each area of the recording head.

  The present invention is an ink jet recording apparatus having a recording head in which a plurality of ejection openings for ejecting ink are formed, and performing recording by ejecting ink from the ejection openings onto a recording medium supported on a support surface, In the support surface, it is possible to store ink to supply moisture by evaporating the ink stored inside around some of the discharge ports formed in the recording head. Further, an ink reservoir forming means is provided.

  According to the present invention, the difference in the amount of moisture supplied to the periphery of the ejection port in the recording head can be reduced for each region of the recording head. Therefore, it is possible to prevent the ink from increasing in viscosity. Accordingly, it is possible to discharge ink from the discharge ports satisfactorily over the entire recording head, and it is possible to maintain high quality of the recorded image.

It is the perspective view shown about the inkjet recording device which concerns on embodiment of this invention. It is sectional drawing which showed the inkjet recording device of FIG. 1 seeing from the side. FIG. 2 is an exploded perspective view illustrating a main part of the ink jet recording apparatus of FIG. 1. FIG. 2 is a side view schematically showing the state of the ink jet recording apparatus of FIG. 1 when the recording head is in a position where recording is performed. FIG. 2 is a side view schematically showing a state in which the recording head is performing a cleaning operation in the ink jet recording apparatus of FIG. 1. FIG. 2 is an enlarged plan view showing a recording unit of the ink jet recording apparatus of FIG. 1. FIG. 2 is an explanatory diagram showing a chip formed on a recording head in the ink jet recording apparatus of FIG. 1. FIG. 2 is an explanatory diagram schematically showing an ink supply system in the ink jet recording apparatus of FIG. 1. FIG. 2 is a block diagram illustrating a schematic configuration of a control system of the ink jet recording apparatus of FIG. 1. 2 is a flowchart illustrating a control flow when a recording operation and preliminary ejection are performed by the ink jet recording apparatus of FIG. 1. FIG. 2 is an explanatory diagram for explaining an ink reservoir when preliminary ejection is performed before recording by the ink jet recording apparatus of FIG. 1. FIG. 2 is an explanatory diagram for explaining an ink reservoir when preliminary ejection is performed while recording is performed by the ink jet recording apparatus of FIG. 1.

  Hereinafter, an ink jet recording apparatus according to an embodiment of the present invention will be described with reference to the accompanying drawings. In the embodiments described below, an ink jet recording apparatus that performs recording by ejecting ink droplets from a recording head will be described as an example. In the present embodiment, a full-line type ink jet recording apparatus equipped with a recording head extending over the entire width direction of the recording medium is used.

  FIG. 1 is a perspective view of an ink jet recording apparatus according to an embodiment of the present invention. FIG. 2 is a cross-sectional view of the ink jet recording apparatus. As illustrated, the ink jet recording apparatus 1 includes recording heads 2 (in the illustrated example, a plurality) arranged in a recording unit 4. The recording head 2 is formed with a plurality of ejection openings for ejecting ink. Ink is ejected from the recording head 2 onto the recording medium 3 supported on the support surface to form an image on the recording medium 3.

  The ink jet recording apparatus 1 includes a paper feeding unit 18 in which the recording medium 3 is set and stored in a roll state at the uppermost stream of the recording medium conveyance path. The inkjet recording apparatus 1 is provided with a transport mechanism for transporting the recording medium 3 at a predetermined speed. While the recording medium 3 fed from the paper feeding unit 18 is transported along the transport path, recording is performed by the recording unit 4 ejecting ink from the recording head 2 to the recording medium 3. Further, the inkjet recording apparatus 1 includes a cutter unit 15 that cuts the recording medium 3 that is roll paper into a predetermined length at a position downstream of the recording unit 4. Further, the inkjet recording apparatus 1 includes a drying unit 16 for drying the recording medium 3 on which recording has been performed, at a position downstream of the cutter unit 15. A paper discharge unit 17 is disposed at the most downstream position along the direction in which the recording medium 3 is conveyed in the inkjet recording apparatus 1.

  A steam supply unit (steam supply means) 5 is disposed upstream of the recording unit 4. A supply duct 9 is arranged inside the steam supply unit 5. The supply duct 9 extends from the intake port to the supply port 10 in the vapor supply unit 5 to the vicinity of the recording head 2 so as to supply the taken-in air as a vapor around the discharge port in the recording head 2. A supply port 10 in the supply duct 9 is directed to a gap provided between the recording head 2 and the recording medium 3. A supply filter 24, a supply fan 8, and a steam generation unit 7 are provided inside the supply duct 9. The air taken in from the intake port is removed by the supply filter 24 from dust mixed in the air. Moreover, in the steam generation part 7, water is sent into the taken-in air and the air is heated, and steam is generated there. Further, a humidity sensor (not shown) for measuring humidity is disposed in the vicinity of the supply port 10 and the nozzle surface of the recording head 2. The vapor generated here is supplied to the periphery of the ejection port formed in the recording head, as will be described later.

  Further, a steam recovery unit 6 is disposed on the downstream side of the recording unit 4. An exhaust duct 12 for exhausting steam is disposed inside the steam recovery unit 6. The suction port 11 of the exhaust duct 12 is disposed facing the gap between the recording head 2 and the recording medium 3 in order to collect the vapor passing between the recording head 2 and the recording medium 3. A suction fan 13 and a suction filter 14 are disposed in the exhaust duct 12. By driving the suction fan 13, the steam supplied by the steam supply unit 5 is sucked from the suction port 11 and collected in the exhaust duct 12. The steam taken into the exhaust duct 12 passes through the exhaust duct 12, and then the exhaust filter 14 collects ink mist generated during the recording operation and mixed with the steam. The vapor from which the ink mist has been collected is discharged from the exhaust port of the vapor collection unit 6.

  When the recording operation is performed by the recording head 2 in the recording unit 4, the recorded recording medium 3 is conveyed to the cutter unit 15. When the recording medium 3, which is roll paper, is cut to a predetermined length by the cutter unit 15, the recording medium 3 is conveyed to the drying unit 16, and hot air is blown onto the recording medium 3 by the drying unit 16, The ink droplets landed on the ink are dried. A heater 21 for generating warm air is disposed below the conveyance path of the recording medium 3 in the drying unit 16. When the drying process is performed in the drying unit 16, the recording medium 3 is discharged from the outlet 19 of the drying unit 16, and the recording medium 3 is discharged to the paper discharge unit 17. In the paper discharge unit 17, the recording media 3 are sequentially discharged, and the respective recording media are stacked and stacked.

  The ink jet recording apparatus 1 includes an ink tank unit 20 that supplies ink to the recording head 2. Ink is supplied from the ink tank unit 20 to the recording head 2 via a tube or the like (not shown). Further, the inkjet recording apparatus 1 includes a power supply unit for supplying electric energy to a drive unit (not shown) in the apparatus, the recording head 2, or a heater 21 for generating warm air in the drying unit 16. 22 is provided.

  FIG. 3 is a perspective view showing the configuration of the recording unit 4 and the steam supply unit 5 and the steam recovery unit 6 arranged adjacent to the recording unit 4. The recording unit 4 is configured in a substantially closed space by the housing frame 107. The recording head 2 is attached to the holder 106. As the holder 106 moves, the recording head 2 held by the holder 106 moves. The holder 106 performs capping to suppress drying of the nozzle surface during non-recording, a predetermined position for performing preliminary ejection, a predetermined position for wiping the ejection port forming surface, in addition to the position for performing the recording operation. The recording head 2 can be moved to a predetermined position or the like. As the holder 106 moves along the vertical direction, the recording head 2 can move along the vertical direction. The recording head 2 moves in a direction (vertical direction) away from the recording surface of the recording medium. Further, the distance between the recording head 2 and the recording medium can be changed by moving the recording head 2 in the vertical direction.

  Due to the difference between the length in the width direction of the recordable portion of the recording head 2 and the length of the maximum width of the transported paper, the recording head 2 has ejection ports that are used frequently and ejection ports that are used less frequently. The holder 106 can move the recording head 2 in the width direction of the recording medium in order to average the deviation in the number of ejections between the respective ejection ports due to the difference in ejection frequency. That is, the recording head 2 can move in a direction (the recording medium width direction X) intersecting the recording medium conveyance direction. The holder 106 is fixed to the belt 104 by an attachment portion 108. Therefore, by driving the pulse motor 103, the pulley 105 attached to the belt 104 is driven, and the holder 106 is moved. At the time of recording, the position of the recording head 2 is controlled so that the number of ejections of ink droplets from the plurality of ejection ports formed in the recording head 2 is averaged. At that time, the driving of the pulse motor 103 is controlled from an external information terminal (not shown) based on data including the size of the recording medium and the accumulated information on the number of nozzle discharges of the recording head 2. By controlling the pulse motor 103, the holder 106 moves to a suitable position so that the number of times of ejection from each ejection port is averaged, and is fixed there.

  FIG. 4 shows a cross-sectional view of the ink jet recording measure 1 when the recording head 2 is disposed at a position when recording is performed. FIG. 5 shows a cross-sectional view of the ink jet recording apparatus 1 during the cleaning operation. The ink jet recording apparatus 1 includes a plurality of recording heads 2 corresponding to a plurality of recordable ink colors, and has four recording heads 2 corresponding to four colors of CMYK in this embodiment. The number of colors that can be recorded by the inkjet recording apparatus 1 is not limited to this. Each color ink is supplied from the ink tank unit 20 to the recording head 2 via an ink flow path.

  The cap unit 6 has a plurality of caps 9 corresponding to the plurality of recording heads 2. In the present embodiment, four caps 9 are provided corresponding to the four recording heads 2. The cap unit 6 has a unit in which four cleaning mechanisms 9 are integrated, and is configured to be slidable in the unit state. Each cap 9 can seal the discharge port when the ink jet recording apparatus 1 is not used, and can suppress the increase in the viscosity of the ink around the discharge port.

  As shown in FIG. 4, when recording is performed, the cap unit 6 is located downstream of the recording unit 4 in the recording medium conveyance direction. As shown in FIG. 5, the cap unit 6 is positioned immediately below the recording head 2 of the recording unit 4 when the ejection port is capped in the inkjet recording apparatus 1. 4 and 5 show the movable range of the cap unit 6.

  FIG. 6 shows a plan view of the configuration of the recording unit 4 in the inkjet recording apparatus 1. As shown in FIG. 6, the recording head 2 is attached near the center of the recording unit 4 of the inkjet recording apparatus 1. A recording medium 3 on which recording is performed by the recording head 2 is transported through a transport path provided in a substantially central portion of the ink jet recording apparatus 1. In the present embodiment, the length of the recording head 2 is 12 inches. Note that the width of the recording medium is not particularly limited, and a recording medium having any width may be used as long as the recording image can be recorded within the recording head width.

  FIG. 7 is a plan view showing the recording head 2 and the recording medium. FIG. 7 shows the respective chips 32 arranged on the base plate 31 when the recording head 2 is viewed from above. Each chip 32 has a plurality of ejection openings, and ink is ejected from the ejection openings.

  Although not shown, an ink receiver formed longer than the recording medium along the width direction of the recording medium is formed at a position corresponding to the recording head 2 on the support surface that supports the recording medium. The ink receiver receives the ejected ink when preliminary ejection described later is performed, and can temporarily store the ink therein.

  Next, the configuration of the ink flow path will be described with reference to FIG. The ink tank unit 20 as a replaceable ink cartridge includes an atmosphere communication port 112 that communicates with the atmosphere. One end of an ink flow path 114 is connected to the ink tank unit 20 via an ink supply pump 113. The other end of the ink flow path 114 is connected to the sub tank 115. By driving the ink supply pump 113, ink can be supplied from the ink tank unit 20 to the sub tank 115.

  The sub tank 115 includes an air communication port 116 that communicates with the atmosphere. An ink flow path 117 and an ink flow path 121 are connected to the sub tank 115. The ink flow path 117 is connected to the ink flow path 120 via the check valve 118 and the first ink circulation pump 119. The check valve 118 can flow ink only in the direction from the sub tank 115 side toward the first ink inflow / outlet port 151 side of the recording head 2 in the ink flow path 117. The ink flow path 120 is connected to the first ink inlet / outlet 151 of the recording head 2. The first ink circulation pump 119 is disposed at the highest position in the ink flow path 117 and the ink flow path 120.

  The ink flow path 121 is connected to the ink flow path 124 via the check valve 122 and the second ink circulation pump 123. The check valve 122 can flow ink only in the direction from the sub tank 115 side toward the second ink inlet / outlet 152 side of the recording head 2. The ink flow path 124 is connected to the second ink inlet / outlet 152 of the recording head 2. The second ink circulation pump 123 is disposed at the highest position in the ink flow path 121 and the ink flow path 124.

  An ink flow path 126 extends from the bottom of the sub tank 115, and an open / close valve 125 is provided in the ink flow path 126. The ink flow path 126 is further connected to the ink flow path 120 between the first ink circulation pump 119 and the recording head 2. Further, an ink flow path 128 having one end connected to the bottom of the buffer tank 127 is connected to the sub tank 115.

  Between the first ink circulation pump 119 and the check valve 118 in the ink passage 117, the ink passage 117 is directed to the ink circulation pump 119, and the ink passage 129 is connected to the buffer tank 127. It is branched to. A check valve 130 capable of passing ink only in the direction from the first ink circulation pump 119 side toward the buffer tank 127 side is provided at a position near the first ink circulation pump 119 in the ink flow path 129. ing. Between the second ink circulation pump 123 and the check valve 122 in the ink passage 121, the ink passage 121 has an ink passage toward the ink circulation pump 123 and an ink passage 131 connected to the buffer tank 127. It is branched to. A check valve 132 that can pass ink only in the direction from the second ink circulation pump 123 side to the buffer tank 127 side is located near the second ink circulation pump 123 in the ink flow path 131. Is provided.

  The buffer tank 127 includes an air communication port 133 so that the internal space communicates with the air. The buffer tank 127 is disposed at the highest position among the ink flow paths 128, 129, and 131. The buffer tank 127 is disposed at a position higher than the sub tank 115. Therefore, the ink returned to the buffer tank 127 flows by its own weight through the ink flow path 128 connected to the bottom to the sub tank 115.

  As the first ink circulation pump 119 and the second ink circulation pump 123, a tube pump is used in this embodiment, and the ink flow direction can be changed by changing the rotation direction of the pump. Further, the tube pump is configured to be able to close the connected ink flow path when stopped. The configuration of the pump need not be limited to the tube pump. Any other configuration of the pump may be used as long as it has a mechanism capable of changing the direction of ink flow and stopping the flow of ink. The ink supply pump 13 only needs to be able to flow ink in at least one direction.

  FIG. 9 shows a block diagram of a control system used in the inkjet recording apparatus 1. A control unit (CPU: Central Processing Unit) 62 that controls the inkjet recording apparatus 1 is connected to a host computer 60 via a reception buffer 61. The CPU 62 is connected to the memory unit 63. When recording is performed, character or image data to be recorded is input from the host computer 60 to the reception buffer 61 of the inkjet recording apparatus 1 and transmitted to the CPU 62. Further, data for confirming whether the data is correctly transferred, and data for notifying the operation state of the inkjet recording apparatus 1 are output from the CPU 62 in the inkjet recording apparatus 1 to the host computer 60 via the reception buffer 61.

  Various data sent to the reception buffer 61 are transferred to the memory unit 63 under the management of the CPU 62 and temporarily stored in a RAM (random access memory) inside the memory unit 63.

  The pulse motor driver 64 drives the pulse motor 103 according to a command from the CPU 62 and moves the recording head 2 by moving the holder 106. Further, based on a command from the CPU 62, a mechanism unit (mechanism unit) 65 such as a cap or a wiper is driven. The transport motor driver 66 controls the transport roller 66 that transports the recording medium 3 according to a command from the CPU 62. Further, the ink circulation motor driver 70 controls the ink supply motor 71 that drives the ink supply pump 13, the first ink circulation pump 19, the second ink circulation pump 23, and the like according to a command from the CPU 62. As described above, the ink supply motor 71 includes an ink circulation motor that drives a circulation pump and an on-off valve. Further, the humidification motor driver 68 drives the humidification motor 69 in response to a command from the CPU 62. By driving the humidification motor 69, the supply fan 8 and the steam generation unit 7 are driven, the steam supply unit 5 generates steam, and the steam is sent to the area between the recording head 2 and the recording medium.

  Further, the recording head 2 ejects ink in response to a command from the CPU 62. In the present embodiment, a heater board (element) that is a silicon substrate in which a heating element for discharging ink droplets, an electric circuit for controlling the heating element, and a driving element are integrated in the recording head 2. Board). On this heater board, a recording head temperature detection sensor for detecting the temperature of the recording head 1 is arranged. As this detection sensor, a sensor using the temperature characteristic of the output voltage of the diode or a sensor using the temperature characteristic of the resistance value of the electrical resistor can be used. Ink is ejected from the recording head 2 by driving a heating element as a recording element by a drive control signal from the CPU 62. When the heat generating element is energized and generates heat energy from the heat generating element, the ink in the ink flow path in the recording head 2 is heated and foamed by film boiling. Is discharged. In the present embodiment, preliminary ejection is performed in which ink droplets that are not involved in recording are ejected from the recording head 2 in response to a command from the CPU. Note that the recording head 2 of the present embodiment employs a system in which film boiling is generated by a heating element and foamed to eject ink droplets, but the present invention is not limited to this. A recording head of a type that deforms a piezoelectric element and thereby discharges liquid inside the recording head may be applied to the recording apparatus, and another type of recording head may be applied to the recording apparatus of the present invention. .

  Next, a series of recording operations in the ink jet recording apparatus of this embodiment will be described. FIG. 10 shows a flowchart when a recording operation is performed by the ink jet recording apparatus of the present embodiment. In this embodiment, preliminary ejection is performed at a stage before printing is performed.

  In S11, a recording operation is started in response to a recording command from the operator. At this time, the pulse motor driver 64 is driven by the pulse motor driver 64 to move the recording head 2 from the cap position in contact with the cap to the recording position where recording is performed. At this time, the mechanism unit 65 such as a cap and a wiper is also driven.

  In S12, the humidification motor 69 is controlled by the humidification motor driver 68, and the steam generated by the steam supply unit 5 is sent toward the area between the recording head 2 and the recording medium. Thereby, the humidity around the ejection port formed in the recording head 2 is increased, and humidification around the ejection port is started. Since the humidity between the recording head 2 and the recording medium is increased, even if there is an ejection port that has not been used for a relatively long period of time, the viscosity of ink around the ejection port is reduced. Can be suppressed.

  However, even if steam is sent into the region between the recording head 2 and the recording medium, the humidity distribution there may not be uniform over the entire longitudinal direction of the recording head 2. When steam is sent between the recording head 2 and the recording medium, the recording medium passing through the recording head adsorbs moisture contained in the steam. At this time, the recording medium containing a large amount of moisture is conveyed to a position corresponding to the recording head 2, so that the moisture contained in the recording medium is supplied around the recording head 2. For this reason, in the vicinity of the recording head 2, the humidity increases at a position corresponding to the area through which the recording medium passes, but the humidity may not increase at a position corresponding to the area through which the recording medium does not pass. In the position where the recording medium passes and the humidity rises, water is sufficiently supplied to the ejection ports formed in the recording head 2, and the viscosity increase with the ink around the ejection ports is suppressed to a small extent. On the other hand, in the area where the recording medium does not pass, the humidity around the recording head 2 does not increase, so that there is a shortage of moisture supplied to the periphery of the ejection port, and there is a possibility that the viscosity increases with ink around the ejection port. There is.

  For this reason, in this embodiment, an ink receiver (ink reservoir forming means) capable of containing ink is formed on the support surface that supports the recording medium. An ink reservoir is formed in the ink receiver by performing preliminary ejection on the ink receiver in the vicinity of the portion where the recording medium does not pass. The ink once stored in the ink reservoir evaporates there. Moisture contained in the ink is supplied to the ejection port, and the humidity around the ejection port increases at the ejection port around the portion where the ink is ejected in the ink reservoir.

  In the present embodiment, before printing is performed, in S13, preliminary ejection for ejecting ink droplets that are not involved in recording is performed on the ink receiver. At this time, the recording head 2 performs preliminary ejection by ejecting ink droplets from the 1024 ejection ports in the region including the ejection port corresponding to the position closest to the end of the recording medium to the ink receiver.

  FIG. 11 is an explanatory diagram for explaining a relationship between an area where a discharge port where preliminary ejection is performed in the recording head 2 and an area through which the recording medium passes. Since the ink receiver is actually formed at a position directly below the recording head 2, the ink receiver is not shown in the drawing. However, in FIG. The figure is shown in a shifted state. As shown in FIG. 11, an ink receiver (ink reservoir forming means) 33 is formed on the support surface that supports the recording medium along the direction in which the recording head 2 extends. The ink receiver 33 may be a groove formed in the support surface 36 that supports the recording medium. Further, a concave portion may be formed on the support surface 36 of the recording medium, and an absorber that absorbs ink may be disposed inside the concave portion.

  The ink droplets ejected by the preliminary ejection are accumulated inside the ink receiver 33 and an ink reservoir 34 is formed. Water evaporates from the ink reservoir 34 and the humidity in the area around the ink reservoir 34 due to the ink ejected by the preliminary ejection in the ink receiver 33 increases. That is, moisture is supplied from the ink reservoir 34 accumulated in the ink receiver 33 by the preliminary ejection to the ejection ports around the ink reservoir 34. Accordingly, it is possible to suppress the increase in the viscosity of the ink at the discharge port around the portion where the ink reservoir 34 is formed. That is, among the ejection ports formed in the recording head 2, the viscosity increase of the ink around the ejection ports can be suppressed to a small extent for the ejection ports formed outside the region through which the recording medium passes. Accordingly, since the recording medium containing a large amount of moisture does not pass through and the moisture can be supplied to the ejection ports formed in the area where the moisture may be insufficient, the ejection ports can be formed over the entire recording head 2. The distribution of the surrounding humidity can be made more uniform. Since it is possible to suppress the ink from being thickened at the ejection port formed outside the region through which the recording medium passes, it is possible to suppress a change in the ink ejection amount at the ejection port. In addition, it is possible to suppress a decrease in ink landing accuracy due to ink thickening. Further, it is possible to suppress the occurrence of non-ejection in which ink droplets are not ejected from the ejection port even when the recording element is driven.

  As described above, in order to supply moisture to the support surface of the recording medium by evaporating the ink stored inside around some of the ejection ports formed in the recording head 2. An ink receiver 33 capable of containing ink is provided. At this time, some of the discharge ports to which moisture is supplied to the surroundings are discharge ports that are predicted to have relatively low ambient humidity compared to other discharge ports. In the present embodiment, the ejection port that is predicted to have low ambient humidity is an ejection port that is formed outside the region through which the recording medium passes. In other words, in the present embodiment, some of the discharge ports are formed at positions corresponding to regions outside the region through which the recording medium that has adsorbed moisture contained in the vapor supplied by the vapor supply unit 5 passes. It is an exit. Some discharge ports are formed outside the area through which the recording medium containing a lot of moisture passes, so that the surrounding humidity is lower than the discharge ports formed inside the area through which the recording medium passes. Low. Therefore, there is a high possibility that the viscosity increase of the ink is promoted as compared with the ejection port formed inside the area through which the recording medium passes.

  In the preliminary ejection before the recording is performed, the ink is ejected by 1024 ejection ports in the region including the ejection port corresponding to the position closest to the end of the recording medium, and the preliminary ejection is performed. . Before the recording, the recording medium has not yet reached the position corresponding to the recording head 2. Therefore, in the preliminary ejection at this time, ink may be ejected from an ejection port located inside the end portion of the recording medium. In other words, the 1024 discharge ports in the region including the discharge port corresponding to the position closest to the end portion of the recording medium may include discharge ports positioned inside the end portion of the recording medium.

  When the preliminary ejection before recording is performed, in S14, the transport roller 66 that transports the recording medium 3 is driven, the recording medium 3 is transported, and the recording head 2 is driven and controlled to record an image. Is done.

  If a certain time elapses while recording is being performed, preliminary recording during recording in which preliminary discharge is performed between recordings is performed in S15. In the preliminary ejection at this time, ink is ejected toward the ink receiver 33 in a region outside the edge of the recording medium.

  FIG. 12 is a diagram illustrating the relationship between the area in which the ejection port for performing preliminary ejection is formed in the recording head 2 and the area through which the recording medium passes, for preliminary ejection performed during recording. The figure is shown. While recording is being performed, the recording medium is disposed at a position corresponding to the recording head 2 on the support surface that supports the recording medium. Therefore, when preliminary ejection is performed, it is necessary to eject ink outside the recording medium. In the preliminary ejection performed during the recording, the preliminary ejection is performed by using only the ejection port further outside the outer end portion of the recording medium. Here, only 512 ejection ports located outside the outer edge of the recording medium are used for preliminary ejection. As described above, in the present embodiment, in preliminary ejection performed during recording, ink is ejected toward a region outside the region where ink is ejected in preliminary ejection performed before recording. The ink ejected by the preliminary ejection is accommodated in the ink receiver 33 located in the region corresponding to the ejection port that ejected the ink. Also by this, the preliminarily ejected ink is accumulated in the ink receiver 33 and an ink reservoir 35 is formed, and moisture from the ink reservoir 35 formed there can be supplied to the periphery of the ejection opening.

  In this embodiment, a suction port for sucking ink mist floating between the recording head 2 and the recording medium is provided in a region outside the region where the ink reservoir 35 is formed. During recording, ink mist is generated together with the main ink droplet as the ink droplet is ejected. In the preliminary ejection performed during recording, the preliminary ejection is performed, and at the same time, the ink mist floating between the recording head 2 and the recording medium is collected. A negative pressure forming means such as a fan may be attached to the interior of the space communicating with the suction port in order to efficiently suck ink mist.

  As the preliminary ejection performed during recording, inter-image preliminary ejection is performed between the recording image to be recorded on the recording medium 3 that is roll paper, separately from the preliminary ejection performed outside the recording medium. Is called.

  Here, in order to perform the preliminary discharge between images, once the preliminary discharge is performed, the preliminary discharge cannot be performed until the recording of the next image is completed. Therefore, in order to perform preliminary ejection between successive recorded images, a certain time interval is required. For this reason, there is a case where it is not possible to perform the inter-image preliminary discharge because the recording of the image has not been completed even though it is necessary to perform the preliminary discharge after a considerable time has passed since the previous inter-image preliminary discharge. As a result, when a state where ink ejection is not performed at some of the ejection ports continues for a long time, the ink ejection amount may change. In addition, there is a possibility that the ink landing accuracy is lowered, or non-ejection in which ink is not ejected even though the recording element is driven may occur.

  In such a case, there is a case where preliminary paper ejection is performed in which ink is ejected onto a recorded image to perform preliminary ejection. Since the preliminary ejection on the paper ejects ink onto a recorded image, generally, the ink color used for the preliminary ejection is limited to an ink color with low visibility (for example, Y).

  When the recording of all the recorded images is completed for the recording data transmitted from the host computer 60, the recording operation is terminated by a command from the CPU in S16. In S17, the humidification motor driver 68 controls the humidification motor 69 in response to a command from the CPU 60, and stops the supply of humidified air to the area between the recording head 2 and the recording medium. In S18, the carriage motor driver 64 drives a mechanism unit (mechanism unit) 65 such as a line head carriage, a cap, and a wiper to move the recording head 2 after recording from the recording position. While the recording head 2 moves to the cap position, the cap unit 6 is moved to a position corresponding to the recording head 2 so that the recording head 2 is capped. Thus, the recording head 2 and the cap unit 6 are moved, and the capping of the recording head 2 by the cap unit 6 is performed, and the main body operation in the inkjet recording apparatus 1 is completed.

  As described above, according to the present embodiment, ink is ejected toward the ink receiver 33 toward a region outside the outer edge of the recording medium, and the ink is stored inside the ink receiver 33. Therefore, when the ink contained in the ink 33 evaporates, the moisture contained in the ink can be supplied to the discharge ports around the ink reservoir inside the ink receiver 33. Thus, moisture can be supplied to the periphery of the ejection port formed outside the region through which the recording medium passes. By supplying moisture, the humidity around the discharge port increases. Accordingly, it is possible to suppress the ink stored in the vicinity of the ejection port in the recording head 2 from being dried and thickened. Since the increase in the viscosity of the ink can be suppressed, it is possible to suppress a change in the ink discharge amount and a decrease in the ink landing accuracy. Further, it is possible to suppress the occurrence of a case where ink droplets are not ejected from the ejection port even though the recording element is driven. As a result, ink can be discharged more favorably over the entire recording head, and the quality of the recorded image can be maintained high.

  The present invention is also effective when the width of the recording medium increases from the previous recording to the next recording.

  In the present embodiment, the ink receiver 33 is formed so as to store the ink ejected during the preliminary ejection. Accordingly, the step of discharging ink into the ink receiver 33 in order to supply moisture to the discharge port with relatively low humidity among the discharge ports formed in the recording head 2 is performed before or during recording. It can also serve as a preliminary discharge process. Therefore, it is not necessary to set a special time for the step of discharging ink into the ink receiver 33 in order to supply moisture to the discharge port having relatively low humidity. Therefore, it is possible to shorten the time required for ejecting ink into the ink receiver 33, and as a result, it is possible to improve the printing throughput.

  In this specification, “recording” (sometimes referred to as “printing”) is used not only for forming significant information such as characters and graphics but also regardless of significance. In addition, “recording” refers to the formation of images, patterns, patterns, etc. on a wide range of recording media, or processing of media, regardless of whether or not they are manifested so that humans can perceive them visually. The case where it is performed shall also be expressed.

  “Recording medium” refers not only to paper used in general recording apparatuses but also widely to cloth, plastic film, metal plate, glass, ceramics, wood, leather, and the like that can accept ink. Shall.

  Further, “ink” (sometimes referred to as “liquid”) should be interpreted widely as in the definition of “recording (printing)”. “Ink” refers to formation of images, patterns, patterns, etc., processing of the recording medium, or processing of ink (for example, coagulation of colorant in the ink applied to the recording medium or It shall also represent a liquid that can be subjected to insolubilization.

Furthermore, unless otherwise specified, the “nozzle” collectively refers to an ejection port or a liquid channel communicating with the ejection port and an element that generates energy used for ink ejection.

DESCRIPTION OF SYMBOLS 1 Inkjet recording device 2 Recording head 33 Ink receptacle 34, 35 Ink reservoir 36 Support surface

Claims (6)

An inkjet recording apparatus that has a recording head in which a plurality of ejection openings for ejecting ink are formed, and performs recording by ejecting ink from the ejection openings to a recording medium supported on a support surface,
In the support surface, it is possible to store ink to supply moisture by evaporating the ink stored inside around some of the discharge ports formed in the recording head. An ink-jet recording apparatus provided with an ink reservoir forming means.   The inkjet recording apparatus according to claim 1, wherein the ink reservoir forming unit stores ink ejected during preliminary ejection.   The ink jet recording apparatus according to claim 1, wherein the partial discharge ports are discharge ports that are predicted to have low ambient humidity. A transport mechanism for transporting the recording medium;
Vapor supply means for supplying vapor to the periphery of the ejection port formed in the recording head;
2. The discharge port according to claim 1, wherein the partial discharge port is a discharge port formed in a region outside a region through which the recording medium adsorbing moisture contained in the vapor supplied by the vapor supply unit passes. 4. An ink jet recording apparatus according to item 3.   The suction port for sucking ink mist floating between the recording head and a recording medium is provided outside the ink reservoir formed in the ink reservoir forming means. The ink jet recording apparatus according to any one of 1 to 4.   6. The ink reservoir formed in the ink reservoir forming means is formed outside an outer end portion of the recording medium while recording is being performed. The inkjet recording apparatus according to Item.

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