JP2007144698A - Inkjet recording device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inkjet recording device which does not deteriorate image quality level even under environments where humidity is low and can complete a printing process as rapidly as possible. <P>SOLUTION: This inkjet recording device has a liquid evaporation promotion mechanism which is arranged in a non-printing region of a recording head and in an adjacent position to the surface of a discharge orifice of a recording head which performs a scanning operation and can increase of the surface humidity of the discharge orifice of the recording head. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an ink jet recording apparatus that performs recording by ejecting ink from nozzles, and in particular, to a same main scanning recording area in a predetermined recording medium using a recording head in which a plurality of nozzle groups of a plurality of nozzles are arranged. The present invention relates to a recording apparatus that performs main scanning a plurality of times by different nozzle groups and completes an image by each main scanning, and relates to reduction of image deterioration factors such as ejection failure.

  The present invention can be applied not only to general printing apparatuses, but also to apparatuses such as facsimile machines having copiers and communication systems, word processors having printing units, and industrial recording apparatuses combined with various processing apparatuses. Can be applied.

  A recording apparatus such as a printer, a copying machine, or a facsimile is configured to record an image formed of a dot pattern on a recording medium such as paper or a plastic thin plate based on image information. This recording apparatus can be classified according to the recording system into an ink jet system, a wire dot system, a thermal system, a laser beam system, etc. Among these, a recording apparatus (inkjet recording apparatus) using the ink jet system is a recording head. For example, ink (recording liquid) is ejected and ejected as droplets from the ejection port of the nozzle, and this is adhered to a recording medium for recording.

  In general, an ink jet recording apparatus includes a carriage mounted with a recording head and an ink tank, a transport unit that transports recording paper, and a control unit for controlling them. Then, the recording head for ejecting ink droplets from a plurality of ejection openings is serially scanned in the direction (main scanning direction) orthogonal to the recording paper transport direction (sub-scanning direction), while the recording paper is set to the recording width during non-recording. Intermittent conveyance is performed with an equal amount. This recording method performs recording by ejecting ink onto a recording sheet in accordance with a recording signal, and is widely used as a quiet recording method at a low running cost. In addition, by using a recording head in which a large number of nozzles for ejecting ink are arranged in a straight line in the sub-scanning direction, the recording head scans the recording paper once, thereby recording up to the maximum width corresponding to the number of nozzles. Is made. Therefore, it is possible to achieve a high speed recording operation.

  In recent years when many recording devices are used, high-speed recording, high resolution, high image quality, low noise, and the like are required for the recording devices, and examples of the recording devices that meet such requirements include the inkjet recording device. be able to.

  However, in the ink jet recording apparatus, when ink is ejected from each ejection port of the recording head, evaporation of the solvent in the ink occurs over time depending on the ink environmental conditions in the vicinity of each ejection port. As a result, the vicinity of the discharge outlet to be discharged first increases in viscosity, making it difficult to discharge. In such a situation, if the non-ejection time is long without replacing the ink components whose density has increased due to ink ejection or suction recovery, normal ejection will be performed the next time ink is ejected for printing at the ejection port. May not be guaranteed. At this time, the maximum time (hereinafter referred to as “one-shot time”) that can guarantee stable ejection with respect to the non-ejection time in a certain environment (temperature, humidity) with respect to the non-ejection time is one parameter of the performance of the inkjet head. ing.

  So far, several ideas have been proposed for extending the firing time by the nozzle structure of the head, the ink composition, and the main body mechanism.

  When printing is performed by scanning the head as disclosed in Patent Document 1, the suction in the main body is performed when the head comes into the non-printing area at every predetermined number of head scanning times corresponding to the time between heads. A method of forcibly sucking ink whose viscosity has been increased from the discharge port by a mechanism is used. However, as the firing time is shorter, the frequency of the suction recovery operation increases, the time for actually completing printing increases, and the performance as a recording device decreases, and the amount of waste ink that is not used for printing also increases. Therefore, it is necessary to obtain the desired performance with minimal suction recovery.

Next, the same effect can be obtained by performing forced ejection (preliminary ejection) a predetermined number of times in the non-printing area. In this case, although the amount of waste ink is reduced rather than suction, in any case, there is a possibility that it may be disadvantageous when speeding up the printing is completed.
JP-A-6-206320

  By performing the recovery operation and the preliminary discharge as described above, fresh ink is supplied into the nozzle. However, immediately after the recovery operation and immediately after the preliminary discharge, the ink solvent starts to gradually evaporate from the vicinity of the discharge port immediately after the discharge port surface is opened to the atmosphere, and the ink viscosity in the vicinity of the discharge port increases with time. End up. If the situation continues until after a certain period of time, the input energy is insufficient to eject ink with increased viscosity in the vicinity of the ejection port, and an abnormal ejection state occurs until the ink of this increased viscosity is ejected. End up. In other words, in this case, the firing time is shortened, and even with the same input energy of the recording head, the volume of ejected droplets of the ink ejected from the recording head, the velocity of the ejected droplets, and the droplets are recorded on the recording medium. There is also a problem that the accuracy of landing on the surface changes.

  Furthermore, when the ink jet recording apparatus is to cope with a medium having a large distance in the head main scanning direction, the firing time is required to be longer. For example, with respect to the A4 size, the longer the firing time is required, the longer the distance between the A3 size, A2 size, and A1 size and the print head in the main scanning direction. At this time, depending on the combination of the performance of the head to be used and the ink composition, it is conceivable that a certain discharge port is closed.

  In other words, during scanning after suction, if there is image data within the firing time, ink can be ejected near the ejection port, and if the humidity in the vicinity of the ejection port can be adjusted to maintain the solvent content in the ink, normal ejection can be performed. .

  Here, a method of avoiding the same firing time by increasing the moving speed of the recording head in the main scanning direction can be considered, but in that case, in order to form the same image, the driving frequency for ejecting ink from the head is also used. Along with this, there is a limit that must be raised.

  In this way, the larger the media size that the inkjet recording device should handle, the longer the time required for the head, while the more problems it has on the head and other performance, and the higher the quality of the recording device. This makes it difficult to achieve high speed.

  To solve the same problem, when printing is performed while supplying humidified air to the recording head itself as disclosed in Japanese Patent Application Laid-Open No. 2000-079696, the humidified air is printed in the print area of the recording medium as the head scans. The top may also be humidified. In this case, although there is an effect of increasing the humidity in the vicinity of the ejection opening, due to the influence of humidified air on the recording medium, the landing area when the ejected recording droplets adhere to the recording medium may be a desired size depending on the humidified state. There is a concern that the developed image quality will be adversely affected.

  Accordingly, an object of the present invention is to provide an ink jet recording apparatus according to a print control means capable of completing printing as fast as possible without degrading image quality even in an environment where humidity is lowered.

  In order to achieve the above object, the recording apparatus of the present invention has the following configuration.

In an ink jet recording apparatus that records an image area determined based on recording data that is input while reciprocally scanning a recording head that performs recording by discharging ink on a recording medium.
An ink jet recording apparatus having a liquid evaporation promoting mechanism.

  Here, it is preferable that the liquid evaporation promoting mechanism is capable of controlling the evaporation of the liquid provided in order to relatively increase the humidity in the vicinity of the recording liquid discharge port provided in the recording head.

  Here, it is preferable that the means for storing the liquid is arranged at a plurality of positions in the area where the recording head scans and the area where printing is not performed on the recording medium in the inkjet recording apparatus.

  Here, it is preferable that the ink jet recording apparatus has means for measuring at least one of humidity and temperature in the vicinity of the recording head.

  Here, the liquid supplied to the means for storing the liquid is preferably a liquid different from the recording liquid.

  Here, it is preferable that the liquid evaporation promoting mechanism has a heating unit for evaporating the evaporated liquid.

  Here, the liquid evaporation promoting mechanism may include an ultrasonic wave generating means for evaporating the evaporated liquid.

  Here, as the liquid supplied to the means for storing the liquid, a recording liquid discharged from a recording head may be used.

  According to the ink jet recording apparatus of the present invention, it is possible to extend the time during which stable ejection can be performed within one scan in an environment in which the solvent content in the ink is likely to evaporate and the density of the ink is likely to change. Good image formation can be performed without causing non-ejection.

(I) Outline of Apparatus Main Body FIG. 11 is an example of an overview diagram of an ink jet recording apparatus IJRA applied to the present invention.

  In the figure, the carriage HC that engages with the spiral groove 5004 of the lead screw 5005 that rotates via the driving force transmission gears 5011 and 5009 in conjunction with forward and reverse rotation of the drive motor 5013 has a pin (not shown). Are reciprocated in the directions of arrows a and b. An ink jet cartridge IJC is mounted on the carriage HC. Reference numeral 5002 denotes a paper pressing plate that presses the paper against the platen 5000 in the carriage movement direction.

  Reference numerals 5007 and 5008 denote home position detecting means for confirming the presence of the lever 5006 of the carriage in this region and switching the rotation direction of the motor 5013. Reference numeral 5016 denotes a member that supports a cap member 5022 that caps the front surface of the recording head. Reference numeral 5015 denotes suction means for sucking the inside of the cap, and performs suction recovery of the recording head through the cap opening 5023. Reference numeral 5017 denotes a cleaning blade, and reference numeral 5019 denotes a member that enables the blade to move in the front-rear direction, and these are supported by a main body support plate 5018. Needless to say, the blade is not in this form, and a known cleaning blade can be applied to this example.

  Reference numeral 5012 denotes a lever for starting suction for suction recovery. The lever 5012 moves with the movement of the cam 5020 engaged with the carriage, and the driving force from the drive motor is controlled by a known transmission means such as clutch switching. Is done.

  These capping, cleaning, and suction recovery are configured so that desired processing can be performed at their corresponding positions by the action of the lead screw 5005 when the carriage comes to the home position side region. Any operation can be applied to this embodiment as long as the operation is performed.

  The ink jet cartridge IJC is a type that is fixedly supported by the positioning means and electrical contacts of the carriage HC placed on the ink jet recording apparatus main body IJRA and is detachable from the carriage HC.

(Ii) Description of inkjet head The inkjet head unit IJU is a head unit that performs recording using an electrothermal transducer that generates thermal energy for causing film boiling to the ink in response to an electrical signal. .

  FIG. 10 is a diagram illustrating the configuration of a preferred print head and printing apparatus to which the present invention is implemented or applied. Hereinafter, each component will be described with reference to these drawings. However, the present invention is not limited to this.

  As can be seen from the perspective view of FIG. 10, the recording head 21 of the present embodiment is a constituent element of the recording head cartridge 18. The recording head cartridge 18 is detachable from the recording head 21 and the recording head 21. It is comprised from the provided ink tank 7 (7a, 7b, 7c, 7d). The recording head 21 discharges ink (or reaction liquid) supplied from the ink tank 7 from the discharge port according to the recording information.

  The recording head cartridge 18 is fixedly supported by positioning means and electrical contacts of a carriage (not shown) placed on the ink jet recording apparatus main body, and is detachable from the carriage. The ink tank 7a is for black ink, the ink tank 7b is for cyan ink, the ink tank 7c is for magenta ink, and the ink tank 7d is for yellow ink. As described above, since each of the ink tanks 7 (7a, 7b, 7c, 7d) is detachable and each ink tank is replaceable, the running cost of printing in the ink jet recording apparatus is reduced.

  Here, the arrangement of the ejection port group of the recording head 21 used in this embodiment will be described.

  FIG. 9 is a schematic front view of a color head for realizing high-density recording used in this embodiment.

  In this example, the ejection port array in which ejection ports of 600 dpi (dots / inch) per row are arranged is shifted by about 21 μm in the sub-scanning direction (paper feed direction) with respect to each other by 2 rows per color. It is provided for the main scanning direction of the head and realizes a resolution of 1200 dpi. Further, in the illustrated example, such ejection port arrays are juxtaposed so that the color order is the same in both the forward direction and the backward direction in the main scanning direction corresponding to the three colors, and a total of 6 columns for the three colors. The head structure is an integral structure that performs recording at 1200 dpi by the ejection port array.

  In the case of the 1200 dpi resolution head shown in FIG. 9, one pixel on the paper surface is about 21 μm square, but when one drop used in this embodiment is about 4 pl, the diameter on the paper surface is about 45 μm. Form circular dots. At this time, the area of one dot is about 1570 μm 2, which is larger than 21 × 21 = 441 μm 2 of one pixel region.

  In the present invention, as shown in FIG. 10, the recording head has a plurality of ejection port arrays each having a plurality of ejection ports provided corresponding to each recording liquid in order to eject recording liquids of a plurality of colors. The plurality of recording liquid ejection port arrays are symmetrically arranged so that the color arrangement order is the same in both main scanning directions of the print head.

(First embodiment)
In the following, as a first embodiment, an ink jet recording apparatus in which a liquid evaporation promoting mechanism can be equipped with a dedicated ink tank for supplying evaporated liquid will be described.

  FIG. 1 is a perspective view showing a configuration of a main part of an ink jet recording apparatus to which the present invention can be applied.

  As shown in FIG. 1, a recording head 21 is mounted on the recording apparatus. Ink to the nozzle rows corresponding to the recording heads 21 is supplied from the ink tank 7.

  At the first home position 51 set outside the print area, a recovery blade 8 and a cap 2 and a recovery unit 8 comprising the evaporation promoting mechanism 1 which is the feature of the present invention are installed. The recovery unit 8 is provided with caps 2 corresponding to the number of recording heads. When recording is not performed, the carriage HC moves to the first home position 51, and the surface of the ink discharge port 16 of the corresponding recording head 21 is sealed by the cap 2 to fix the ink due to the evaporation of the ink solvent or dust. Prevents clogging due to foreign material.

  Further, the cap 2 is provided with a transport pipe 47 for sending ink sucked from the recording head 21 by the suction operation to the waste liquid tank 46.

  The evaporation promotion mechanism 1 is provided at the second home position 52 set outside the printing area.

  The contact portion of the cap 2 with the recording head 21 is formed of an elastic body such as synthetic rubber. The cap 2 faces the recording head 21 at the home position 51 of the recording head 21, and moves in the head direction when not printing or when the recovery operation of the recording head 21 is performed. I do. Here, the cap 2 is connected to the pump 48 by a waste liquid tube 47, and the ink passing through the waste liquid tube 47 is finally stored in the waste liquid absorber 46.

  Here, the evaporation promoting mechanism 1 is supplied with the evaporation liquid from the ink tank 4 for the evaporation liquid through the supply tube 5 as shown in the schematic diagram of FIG. A controllable valve 9 is provided in the middle, and the supply of the evaporation liquid 3 can be controlled. In addition, an absorber 6 is mounted in the evaporation promotion mechanism 1, and in the present embodiment, the evaporation liquid 3 in the absorber 6 is vaporized by applying a voltage to the heater 7 for heating. ing.

  In addition, a humidity sensor (not shown) is attached to the evaporation promotion mechanism 1, and a temperature sensor (not shown) is attached to the recording head 21, and the MPU 23 determines the humidity based on the information obtained from the temperature sensor and the humidity sensor. Is optimally controlled so that the humidity in the vicinity of the ink ejection port array of the recording head 21 can be controlled to an appropriate state during and before and after printing.

  Here, a Di element or the like disposed in the recording element substrate 11 is used as the temperature sensor, and humic substances such as lithium chloride, ceramics, and polymers are used as the humidity sensor, and the change in the amount of water vapor is measured by electric resistance. Use a hygrometer that measures electrical changes such as electrical capacity. However, the temperature sensor and the humidity sensor are not limited to this.

  Further, as a function of the recovery unit 8 part, the capping function of the cap part 31 is performed in order to eliminate ejection failure and clogging from the ink ejection port with low recording frequency, and further, recording is performed in a state away from the ink ejection port. The head 21 may be used as an ink receiver for preliminary ejection performed immediately before the recording operation. This is done in the cap 31 when the recording head 21 passes over the cap 31.

  In addition, by arranging a cleaning blade (not shown), a so-called extraction member, at a position adjacent to the cap 2, it is possible to clean the ink discharge port forming surface of the recording head 21.

  The humidity described in the present embodiment is relative humidity, and is defined by the formula [1] below.

Uw = xv / xvs × 100 = e / es × 100≈e / ew × 100 [1]
V: Volume of humid air
T, t: temperature of wet air T: temperature of wet air (absolute temperature)
t: temperature of wet air (Celsius temperature)
mv: mass of water vapor in humid air es: water vapor pressure of saturated wet air ew: saturated vapor pressure of water xv: mole fraction of water in wet air xvs: mole fraction of water in saturated wet air

[Control of evaporation promotion mechanism]
The operation of the recovery unit 8 performed during printing according to the present invention will be described with reference to the flowchart shown in FIG.

(1)
It is determined whether or not a recording signal is received. If no recording signal is input, capping is performed by a suction recovery cap. When there is a recording signal input, the following control is started.

(2)
First, the recording head 21 is moved to the first home position 51, and above all the cap 2. Next, the cap 2 is raised by a motor (not shown) so as to bring the cap 2 into close contact with the surface of the recording head 21. Then, a pump (not shown) communicating with the cap 2 is driven to operate the suction pump. In this state, the thickened ink in the vicinity of the discharge port 16 of the recording head 21 is sucked to complete the recovery for adjusting the ink in the vicinity of the discharge port to a desired physical property state. Immediately after this, the pump is controlled to stop, the suction operation is terminated, and the suction recovery operation is terminated.

  In parallel with this, the necessity of humidification control according to the temperature as shown in FIG. 6 based on the information of the temperature detection Di sensor provided in the recording head 21 and the information of the humidity detection device provided in the recovery unit 8 part. If humidification is required, a voltage is applied to the heater 7 at the same time as supplying the evaporation liquid 3 into the evaporation promoting mechanism 1 to prepare for evaporation of the evaporation liquid 3 in the absorber 6.

  The evaporating liquid 3 is preferably a liquid that does not contain components such as magnesium and calcium as much as possible, and preferably has a small amount of substances that precipitate when the solvent is evaporated.

  Subsequently, the cap 2 which is in close contact with the surface of the recording head 21 is lowered by a motor (not shown), and the surface of the recording head 21 is opened to the atmosphere. Further, the recording head 21 performs preliminary ejection into the cap 2 in order to eliminate ink wetting on the surface of the ejection port due to the cap 2 attachment or foreign matter adhering to the surface, and to keep ink ejection for printing in a good state.

  In the case of a recording apparatus having no conventional humidifying mechanism, evaporation of the solvent in the ink proceeds from the surface of the ejection port 16 from this moment depending on the environmental conditions.

  On the other hand, in the present invention, as shown in FIG. 3, immediately after the suction recovery or preliminary discharge is completed, the recovery unit 8 is moved onto the evaporation promoting mechanism 1. At this time, by moving up and down by a motor (not shown) of the recovery unit 8 part, the shortest position of the evaporation promotion mechanism 1 with respect to the ejection port surface of the recording head 21 is less than the distance from the recording medium to the ejection port surface of the recording head 21. In addition, the recording head 21 is disposed at a position not in contact with the ejection port surface. Further, since the heating heater 7 in the evaporation promotion mechanism 1 is already in operation, the atmosphere near the discharge port has a desired humidity due to the evaporation of the evaporated liquid 3 in the absorber 6, and the vicinity of the discharge port 16. The evaporation of the solvent in the ink is suppressed.

(3)
Thereafter, the carriage 40 is scanned based on the recording data, that is, the recording head 21 is reciprocally scanned in the main scanning direction different from the arrangement direction of the plurality of ejection ports 16 and the amount is less than the plurality of ejection port arrangement widths. The recording medium 10 is transported relatively in the sub-scanning direction orthogonal to the main scanning direction, and an image is formed on the recording medium 1.

  At this time, the evaporation promotion mechanism 1 which is a feature of the present invention always operates the heater 7 and moves the recording head 21 to the first home position 51 and the second home position 52 which are non-printing areas. In addition, it is possible to keep the humidity in the atmosphere in the vicinity of the ejection port 16 on the condition that the solvent does not easily evaporate, and to suppress the increase in the viscosity of the ink in the vicinity of the ejection port 16. Since this effect is more effective as the distance between the evaporation promoting mechanism 1 and the recording head 21 is smaller, the evaporation promoting mechanism 1 is raised by a motor (not shown) within the range where it does not contact the recording head 21 as with the cap 2 part. I am letting.

  Further, the evaporation promotion mechanism 1 is preferably provided at both the first home position 51 and the second home position 52 in the main scanning area of the recording head 21 as shown in FIG. As shown, it may be provided only on one side.

(4)
After the formation of a desired image on the recording medium 1 is completed, the driving of the heating heater 7 of the evaporation promotion mechanism 1 and the supply of the evaporation liquid 3 are also completed in synchronization with this.

  According to the embodiment described above, humidifying the vicinity of the ink ejection port array of the recording head according to the measurement results of the temperature sensor and the humidity sensor suppresses evaporation of the ink solvent component near the ejection port and reduces the change in the viscosity of the ink. This makes it possible to improve the firing time, which is the time during which normal ejection can be guaranteed from the non-ejection state.

  Further, in the present invention, when the recording head 21 is not on the upper surface of the evaporation promoting mechanism 1, the humidified air diffuses into the recording apparatus but does not directly contact the recording medium. Has little influence on the ink absorption characteristics, and does not affect the quality of the printed image.

[Regarding the departure time]
Here, the preset firing time of the recording head 21 will be described with reference to FIG.

  For example, consider a case where printing is performed on the recording medium 1 having a maximum distance <WM> in the main scanning direction of 640 mm. At this time, it is assumed that the recording head 21 on the carriage moves on the recording medium 1 at 25 inches / sec when printing the image area <W1all> of the first scan. However, when the recording head 21 moves to the home position, acceleration / deceleration areas <WA> and <WB> are required, and the distance by which all the ejection ports 16 aligned in the main scanning direction of the recording head 21 itself move the recording medium 1. In consideration of this, the distance that the recording head 21 moves at a constant speed needs to be 659 mm.

  In this case, the time required to move the scanning area at a constant speed was 1.04 sec, and the time required for acceleration / deceleration was 0.15 sec. That is, the total time required for the recording head 21 on the carriage to print the image area <W1all> for the first scan is 1.19 sec.

  When used in combination with the recording head 21 used in this embodiment and an ink using a pigment dispersion as a colorant having a viscosity of 2 to 4 mPa · s and a surface tension of 20 to 40 mN / m, a temperature of 30 ° C. and a humidity of 10 As a result of measuring the firing time in a% environment, the firing time that can guarantee normal ejection was 0.9 sec. On the other hand, when the driving / non-driving of the evaporation promotion mechanism 1 of the present embodiment was compared, the time required to ensure normal ejection was improved to 1.8 s.

  In other words, when printing is performed on the recording medium 1 having the maximum distance <WM> in the main scanning direction of 640 mm, and there is no evaporation promoting mechanism 1, a certain ejection port 16 has a firing time of 1.. Since it is 0 sec or less, there is a case where normal ejection cannot be guaranteed at the rear end portion in the printing area of one main scan.

  However, by driving the evaporation promotion mechanism 1 of the present invention, a sufficient discharge time can be secured in the case of this embodiment, so that stable ejection can be guaranteed.

(Second Embodiment)
Next, as a second embodiment, a case will be described in which the waste ink collected in the cap 2 from the recording head 21 is used as the evaporated liquid supplied to the liquid evaporation promotion mechanism used in the first embodiment.

  In the first embodiment, the cap 2 is connected to the pump 48 by the waste liquid tube 47, and the ink that has passed through the waste liquid tube 47 is finally stored in the waste liquid absorber 46 part.

  In the present embodiment, as shown in FIG. 7, the cap 2 and the evaporation promoting mechanism 1 are connected by a waste liquid tube 47, and the evaporation promoting mechanism 1 is connected by a pump (not shown) and a waste liquid tube 47.

  At this time, the cap 2 is raised by a motor (not shown) so as to bring the cap 2 into close contact with the surface of the recording head 21. Then, a pump (not shown) is driven to operate the suction pump. At this time, the evaporation promoting mechanism 1 also rises simultaneously with the cap 2 and is brought into close contact with a part of the carriage 40, so that the inside of the evaporation promoting mechanism 1 is in a sealed state. Therefore, once the waste liquid collected from the cap 2 is held in the absorber 7 in the evaporation promotion mechanism 1, the waste liquid that cannot be absorbed is further stored in the waste liquid absorber 46 through the waste liquid tube 47. Subsequently, the cap 2 which is in close contact with the surface of the recording head 21 is lowered by a motor (not shown), and both the surface of the recording head 21 and the evaporation promoting mechanism 1 are opened to the atmosphere. At this time, the sucked waste liquid is held in the absorber 7 in the evaporation promotion mechanism 1. That is, this waste liquid is used as the evaporated liquid 3.

  Other processes are the same as those in the first embodiment.

  As described above, as in the first embodiment, the shot-out performance is improved and stable image formation can be guaranteed. In addition, in the second embodiment, waste ink at the time of preliminary ejection and suction is used as a transpiration solvent, so that it is not necessary to separately provide the evaporating liquid 3, so that the amount of waste ink can be reduced, and the recording apparatus The running cost during use can also be reduced.

(Third embodiment)
Next, as a third embodiment, ultrasonic waves may be used as a method for vaporizing the evaporated liquid. In this case, as shown in FIG. 4, in the evaporation promotion mechanism 1 shown in the first embodiment, in addition to the absorber 6 that holds the evaporated liquid 3, an ultrasonic generator is provided in the heater 7 portion. ing.

  In addition, as the evaporating liquid used in this example, any of the evaporating liquids 3 shown in the first and second embodiments may be used.

  As described above, as in the first embodiment, the shot-out performance is improved and stable image formation can be guaranteed.

1 is a schematic diagram illustrating an ink jet recording apparatus according to a first embodiment of the present invention. It is a schematic diagram explaining the inkjet recording device of this invention. It is the schematic diagram which expanded the recovery unit part which the home position of the inkjet recording device which concerns on this invention comprises. It is a schematic diagram which shows the part which supplies an evaporation liquid to the evaporation promotion mechanism in the 1st and 3rd embodiment of this invention. It is a flowchart explaining operation | movement in the case of using the evaporation promotion mechanism of the inkjet recording device which concerns on this invention. It is a graph which shows the conditions of temperature and humidity which operate | move the evaporation promotion mechanism of this invention. It is a schematic diagram which shows the part which supplies an evaporation liquid to the evaporation promotion mechanism in the 2nd Embodiment of this invention. It is a schematic diagram for demonstrating regarding the one-shot time described in this invention. It is a typical front view of the color head used in this embodiment. It is a schematic diagram showing the whole color head used in this embodiment. 1 is a schematic view of a general ink jet recording apparatus applied to the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Evaporation promotion mechanism 2 Cap 3 Evaporating liquid 4 Evaporating ink tank 5 Supply tube 6 Absorber 7 Heater 8 Recovery unit part 9 Valve 10 Recording medium 11 Recording element 12 Ejection port array (C)
13 Discharge port array (M)
14 Discharge port array (Y)
15 Discharge group 16 Discharge port 18 Recording cartridge 19 Conveyance motor 37 Feed roller 38 Step motor 46 Waste liquid absorber 47 Waste liquid tube 48 Pump 51 First home position 52 Second home position HC Carriage

Claims (8)

In an ink jet recording apparatus that records an image area determined based on recording data that is input while reciprocally scanning a recording head that performs recording by discharging ink on a recording medium.
It is a non-printing area of the recording head, and is arranged at a position close to the discharge port surface in the recording head to be scanned,
An ink jet recording apparatus having a liquid evaporation promoting mechanism capable of increasing the humidity of a discharge port surface of a recording head.   The inkjet recording apparatus according to claim 1, wherein the inkjet recording apparatus includes at least one of means for measuring humidity in the vicinity of the recording head and means for measuring temperature in the vicinity of the recording head. apparatus.   The liquid evaporation promotion mechanism can control the evaporation of liquid in order to control the humidity of the discharge port surface provided in the recording head at least from the start of printing to the end of printing according to the temperature or humidity around the recording head. The inkjet recording apparatus according to claim 1, wherein the inkjet recording apparatus is a means.   The closest distance between the liquid evaporation promoting mechanism and the discharge port surface of the recording head is not in contact with the discharge port surface of the recording head at the shortest, and is the maximum distance between the recording medium and the discharge port surface of the recording head. The inkjet recording apparatus according to any one of claims 1 to 3, wherein:   The ink jet recording apparatus according to claim 1, wherein the liquid is an evaporable liquid different from the recording liquid.   5. The ink jet recording apparatus according to claim 1, wherein the liquid evaporation promoting mechanism includes a heating unit for evaporating the evaporated liquid.   5. The ink jet recording apparatus according to claim 1, wherein the liquid evaporation promoting mechanism includes an ultrasonic wave generating unit for evaporating the evaporated liquid. 6.   The ink jet recording apparatus according to claim 1, wherein the liquid is a recording liquid discharged from a recording head.

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