JP4100896B2 - Inkjet recording apparatus and inkjet recording method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an ink jet recording apparatus and an ink jet recording method, and more particularly to an ink jet recording apparatus and an ink jet recording method that perform preliminary ejection.
[0002]
[Prior art]
Recording devices with functions such as printers, copiers, facsimiles, etc., or recording devices used as output devices such as composite electronic devices including computers and word processors, workstations, etc. An image (including characters and symbols) is recorded on the recording medium. Examples of the recording method of the recording apparatus include ink jet, wire dot, thermal transfer, and laser. Among these recording methods, the inkjet method ejects fine granular ink droplets from each nozzle of the recording head based on an electrical recording signal, and applies the ink droplets to a recording medium provided facing the nozzle. Characters, figures, etc. are recorded by landing. Furthermore, in an ink jet recording apparatus generally called a serial type, scanning is performed with the recording head facing the recording medium in a direction crossing the conveyance direction of the recording medium, and ink is ejected onto the recording medium during this scanning. One line is recorded, and then a predetermined amount of paper is fed. In this way, recording can be performed on the entire recording medium by repeating recording and paper feeding. Further, in a line type recording apparatus using a recording head in which nozzles are arranged to be larger than the paper width of the recording medium, the recording head does not scan, and when the recording medium is arranged at a predetermined position, the recording head collectively records one line. Then, a predetermined amount of paper feed (pitch feed) is alternately repeated to form an image on the entire recording medium. Such an ink jet method has been widely used in recent years because it has advantages such as relatively low noise during recording, high-definition image output, and high recording speed.
[0003]
By the way, the ink release mechanism in the recording head of the ink jet recording apparatus is as follows. Using discharge pressure generating elements such as piezoelectric elements or electrothermal conversion elements (hereinafter referred to as “heaters”) provided in the recording head, the electrical energy is converted into mechanical energy to discharge ink. In particular, a so-called thermal ink jet recording method (Japanese Patent Application Laid-Open No. 61-59911-4) using ink generated by instantaneously boiling ink by heating a heater and using the pressure of bubbles generated at that time reduces the size of the apparatus and the height of the recording head. It is known to have features such as easy density. In this thermal ink jet recording method, the volume of ejected ink droplets is always kept stable without being influenced by external factors such as environmental temperature, and bubbles generated on the heater are used to obtain a higher quality image. Japanese Laid-Open Patent Publication No. 4-10940-42 discloses a method for communicating with the outside air during droplet ejection. As a recording head for realizing this method, a recording head having a short distance (for example, 15 to 30 μm) between the heater and the discharge port is suitable. When the distance between the heater and the discharge port is short, the generated bubbles are in constant communication with the atmosphere, and this distance almost determines the volume of the ink droplet to be discharged, so it is also effective for discharging small droplets. It is attracting attention as a method.
[0004]
In addition, water-based inks to which dyes using water as a solvent, organic solvents, surfactants and the like are added as inks used in ink jet recording apparatuses are currently mainstream. In such water-based ink, volatile components such as moisture contained in the ink may evaporate with time or temperature. In particular, when the volatile component of the ink in the recording head evaporates during non-ejection, the ink viscosity, solvent composition, and dye concentration in the vicinity of the ejection port change. If ink discharge is performed in a state in which this change has further progressed, the ink may not be discharged even if a discharge pulse is applied to the nozzle drive element, or a so-called clogging phenomenon may occur, or the various characteristics of the discharged ink droplet, such as the discharge direction, may occur. Detrimental effects such as instability and increased dot density may occur. In particular, this phenomenon is more likely to occur as the nozzle outlet diameter decreases. In a photographic image or the like, since a higher quality image is required, ink droplets ejected in recent years tend to be miniaturized, and the above-described adverse effects tend to be affected. In addition, if water-resistant dyes are used in the ink, or if a pigment dispersant or a number of additives for preventing color mixing or improving light resistance is added to the ink, the state of the ink during non-ejection tends to deteriorate. In some cases, the above-described adverse effects are likely to occur. In order to prevent such an adverse effect, the following method has been conventionally executed. As a first method, before or during recording, the recording head is temporarily moved to a predetermined position other than the recording area, and a predetermined amount of ink droplets are ejected from all ejection ports, so-called preliminary ejection is performed. Can be mentioned. The preliminary ejection may be performed at an inconspicuous position in the recording area. In the case of a multi-nozzle type recording head, preliminary ejection is performed before recording when recording is performed after a certain time has elapsed since the previous recording, or not all nozzles in the recording head are always used. In addition, it is periodically executed during recording. Further, suction processing by a pump provided at a predetermined position may be executed together. The ink consumption in the preliminary ejection is determined by the number of preliminary ejection pulses, the ejection amount of the nozzles, and the number of nozzles. The number of preliminary ejection pulses depends on the nature of the ink, the nozzle shape, and the time of main scanning in the inkjet recording apparatus. It is determined as appropriate according to the downtime from the previous recording.
[0005]
As the second method, there is a method described in JP-A-57-61576. In this method, when non-ejection, the piezoelectric vibrator is driven with a low driving voltage that does not eject ink droplets, and the meniscus surface of the ejection port is vibrated to stir the ink in the nozzle and bring it close to the ejection port. The distribution of the viscosity in the nozzle is relaxed by replacing the concentrated ink having a high viscosity with the low viscosity ink existing in another portion.
[0006]
FIG. 1 schematically shows how the viscosity distribution of the ink in the vicinity of the ejection port changes by this method. It is assumed that the viscosity of the ink is higher in a portion having a higher density in the drawing, that is, a portion having a higher halftone dot density. FIG. 9A shows a state before being vibrated, and since a certain time has passed since the previous recording, the ink in the vicinity of the ejection port has a high viscosity. When the meniscus surface is vibrated by driving the piezoelectric element to such an extent that no ink is ejected in this state, as shown in FIG. Pulled back to. As a result, as shown in FIG. 5C, the low-viscosity ink that is present near the discharge port at the back of the nozzle is pushed out toward the discharge port. By repeating this operation a plurality of times, the viscosity of the ink existing in the vicinity of the ejection openings is averaged as shown in FIG.
[0007]
This can improve the state of the ink without discarding the ink, so that the ink is not wasted compared to the first method.
[0008]
[Problems to be solved by the invention]
However, the above-described conventional method for eliminating discharge defects due to an increase in ink viscosity has the following problems.
[0009]
In the first method, as the discharge port diameter becomes smaller, the degree of increase in the viscosity of the ink increases, and the number of preliminary discharges increases accordingly. Therefore, not only the amount of ink consumed unnecessarily apart from recording increases, but also the capacity of the waste ink tank for storing waste ink increases as the amount of ink consumed in this preliminary ejection increases. Further, when preliminary ejection is performed during the recording operation, there arises a problem that the number of recordings on the recording medium per unit time, that is, the throughput decreases. In addition, when the preliminary ejection method directly onto the recording medium is reached, even the image quality is deteriorated.
[0010]
Further, in the second method, it is not effective to provide a piezoelectric element only for vibrating the meniscus surface for a recording head of a thermal ink jet recording method using a heater for discharging ink droplets. . In addition, when recent highly volatile ink is used, it can be seen that the ink with high viscosity in the vicinity of the ejection port does not move as long as the meniscus surface is vibrated.
[0011]
In view of such a conventional problem, an object of the present invention is to provide an ink jet recording apparatus and an ink jet which can suppress wasteful consumption of ink in preliminary ejection and maintain a nozzle state capable of stably ejecting ink droplets at all times. It is to provide a recording method.
[0013]
[Means for Solving the Problems]
The inkjet recording apparatus of the present invention has a plurality of ejection openings arranged in a recording head. Every predetermined number Driven simultaneously As a set of discharge ports Multiple drive blocks Divided into For each drive block give Heat signal By giving a heat signal to each discharge port at a predetermined drive frequency while switching at predetermined time intervals An ink jet recording apparatus that ejects ink droplets onto a recording medium, and in the preliminary ejection, give Heat signal By switching at a time interval shorter than the predetermined time interval at the time of normal recording, a heat signal is given to each discharge port at a timing equal to the predetermined driving frequency at the time of recording. Preliminary ejection means for ejecting ink droplets is provided.
[0015]
The inkjet recording method of the present invention includes a plurality of ejection openings arranged in a recording head. Every predetermined number Driven simultaneously As a set of discharge ports Using an inkjet recording apparatus having a plurality of drive blocks, Heat signal given to each drive block At predetermined time intervals A heat signal is sent to each outlet at a predetermined drive frequency while switching. An ink jet recording method for ejecting ink droplets onto a recording medium by applying the ink to each drive block during preliminary ejection. give Heat signal By switching at a time interval shorter than the predetermined time interval at the time of normal recording, a heat signal is given to each discharge port at a timing equal to the predetermined driving frequency at the time of recording. A preliminary ejection step for ejecting ink droplets is provided.
[0016]
According to the above configuration, by ejecting ink droplets only from some of the plurality of ejection ports, the meniscus surface of the ejection port is vibrated, and the ink with high viscosity near the ejection port and the vicinity of the common liquid chamber When the ink is ejected from the remaining ejection ports that were not ejected by the ejection operation, the ink having a high viscosity can be effectively ejected, and the state in the vicinity of the ejection ports. Make good.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings.
[0018]
(Embodiment 1)
FIG. 2 is a perspective view of an ink jet recording apparatus according to an embodiment of the present invention.
[0019]
The recording head unit 21 is an integrated recording head and ink tank. The recording head unit 21 is mounted on a carriage 22 and moves as the carriage moves in the direction of the arrow a or b along the guide line 23 during recording. The recording head 21 has nozzles arranged at positions facing the recording medium P. Further, the nozzles are arranged in a predetermined arrangement in a direction perpendicular to the moving direction of the recording head (arrow a and b directions). In this embodiment, the recording head is a multi-nozzle head in which a total of 128 nozzles are arranged.
[0020]
During recording, the carriage 22 moves in the direction of arrow a from the recording start position, and ink droplets are ejected from the nozzles toward the recording medium P along with the movement. When the carriage moves to the other end of the recording medium P, the transport roller 24 rotates by a certain amount and transports the recording medium P in the direction of arrow c. During this transport operation, the carriage 22 moves in the direction of arrow b and returns to the recording start position. Then, the recording is performed again by moving in the direction of arrow a. Thus, recording is performed on the entire recording medium by repeating the recording operation and the recording medium conveyance operation.
[0021]
In the recording head (not shown), an ink path extends from each ejection port, and the ink path communicates with the common liquid chamber. The common liquid chamber is connected to the ink tank, and ink is supplied from the ink tank. The supplied ink is filled up to the normal discharge port. A portion obtained by combining the ejection port and the ink path for each ejection port roughly corresponds to a “nozzle”. Furthermore, a heater is provided corresponding to each discharge port. When recording, an electric signal is applied to a predetermined heater, and when the heater generates heat by the electric signal, the ink in the ink path instantaneously boils and bubbles are generated. A predetermined amount of ink is discharged from the discharge port by the generation pressure of the bubbles generated by the film boiling.
[0022]
By the way, if the ink is not recorded for a long time, the ink changes, for example, the viscosity of the ink near the ejection port increases. Since the ink with increased viscosity becomes unstable in the ejection direction or clogged in a severe state, it is necessary to periodically remove the ink with increased viscosity. In the present embodiment, preliminary discharge and suction processing are performed to always keep the nozzle state good.
[0023]
At the time of preliminary ejection, the recording head is moved to the position of the preliminary ejection cap 25 provided outside the recording area. When the preliminary ejection cap 25 covers the nozzle portion of the recording head, the recording head performs preliminary ejection. Details of the preliminary discharge method will be described below.
[0024]
Further, even during the recording operation, by passing the recording head in front of the blade 26, it is possible to perform wiping and remove dust or the like on the surface of the discharge port.
[0025]
Next, details of the preliminary ejection method in the present embodiment will be described.
[0026]
In a multi-nozzle type recording head in which a plurality of nozzle arrays are arranged, a so-called crosstalk phenomenon occurs in which the pressure and ink flow at the time of droplet discharge are transmitted to the surrounding nozzles through the common liquid chamber and vibrate the meniscus surface of the nozzles. May occur. Crosstalk causes the discharge amount and refill time to fluctuate and impairs image quality.Therefore, various methods for nozzle shape and recording methods have been proposed and implemented in order to reduce the effects of crosstalk during recording. ing.
[0027]
However, in the present embodiment, this crosstalk phenomenon is used at the time of preliminary ejection, and the pressure fluctuation in the common liquid chamber is positively caused to vibrate the meniscus surface to mitigate the increase in ink viscosity near the ejection port. Normally, crosstalk is easily affected by the nozzle shape and the distance between the nozzle and the ink supply port. However, in the case of a multi-nozzle head, the number of pits that are simultaneously driven simultaneously has the greatest influence on the crosstalk. That is, the crosstalk phenomenon is more likely to occur as the number of pits driven simultaneously increases. Furthermore, it is generally known that the pressure and ink flow received by driving adjacent nozzles have the greatest influence.
[0028]
FIG. 3 is a diagram showing a change in position of the meniscus surface of the non-driven nozzles as a change with time measured based on the position in the stationary state when every 128 nozzles of the recording head of the present embodiment are driven. It is.
[0029]
Note that time 0 in the figure is the drive start time of the drive nozzle. The change in the position of the meniscus surface from the discharge port end depends on the structure of the nozzle, the way of driving, the structure of the ink chamber, etc., but the driving at this time varies by about ± 2 μm compared to the meniscus at rest, The “+” position in the graph is the convex state of the meniscus surface, and the “−” position is the concave state of the meniscus surface. From this figure, it can be seen that the meniscus surface of the non-ejection nozzle vibrates. That is, it is expected that a phenomenon in which the ink having a high viscosity near the discharge port and the ink having a low viscosity on the common liquid chamber side are mixed inside the nozzle due to the vibration of the meniscus surface as shown in FIG. The In this way, it is less in the case where preliminary ejection is performed in a state where the viscosity of the ink near the ejection port is relaxed, because ink with high viscosity is discharged out earlier than when preliminary ejection is performed without relaxation of the viscosity. The nozzle can be brought into a good state by the number of preliminary discharges.
[0030]
In the present embodiment, it is assumed that the preliminary ejection process is executed after 30 seconds have elapsed from the end of the recording signal.
[0031]
In the preliminary ejection process, the recording head is retracted from the recording area to the position of the preliminary ejection cap 25, and preliminary ejection is performed a plurality of times at this position. However, in the first preliminary ejection operation, every other nozzle is ejected out of 128 nozzles in the recording head. In this first preliminary discharge, 200 continuous discharges are performed. Next, only the remaining nozzles that were not discharged in the first preliminary discharge are discharged 10 times.
[0032]
Actually, even if the recording immediately after the preliminary ejection is performed by such a preliminary ejection method, the recording result is stable, and compared with the recording result after performing preliminary ejection 200 times with all the conventional nozzles. It was innocent.
[0033]
That is, the preliminary ejection method of the present embodiment can reduce the amount of ink consumed for preliminary ejection compared to the conventional preliminary ejection method. As described above, in the present embodiment, the nozzles that discharge every other nozzle are determined in the first preliminary discharge, but the present invention is not limited to this, and the discharge is performed every r (r: any integer). You may determine the nozzle to perform. Further, when the nozzles are arranged in two rows with the ink supply port interposed therebetween, only one of the rows may be discharged in the first preliminary discharge. In any of these cases, the number of preliminary ejections for the second time can be reduced, and the ink consumption as a whole can be reduced.
[0034]
(Embodiment 2)
Generally, in many ink jet recording apparatuses, not all the nozzles in the recording head perform the ejection operation simultaneously during recording. In general, the nozzles are divided into a plurality of drive blocks from the arrangement and are divided into drive blocks, and at the time of printing, a separate and divided drive method is used in which each drive block is time-division driven.
[0035]
This divided driving method is an effective method for reducing the size of power source members such as a head driving power source and a power connector flexible cable. In particular, in the case of a recording head using a heater, in order to perform stable ejection in consideration of the characteristics of the heater and ink, etc., the voltage value fluctuation should be extremely small or the voltage value must be finely adjusted. Since it is necessary, it is not preferable to increase the capacity of the power source, and the above method is effective in avoiding this.
[0036]
In the present embodiment, a preliminary ejection method in a separation-divided drive type recording head will be described.
[0037]
The configuration of the ink jet recording apparatus of the present embodiment is the same as that of the first embodiment.
[0038]
The recording head separation / division drive in this embodiment is performed as follows.
[0039]
FIG. 4 is a diagram illustrating a timing table of the heat signal of each heater of the recording head according to the present embodiment.
[0040]
The 128 nozzles arranged in the direction perpendicular to the directions of arrows a and b in FIG. 2 are divided into 16 sections in units of 8 pieces. In FIG. 4, a state in which the nozzle row is viewed from the front of the discharge port is shown at the center.
[0041]
In FIG. 4, the timing table on the left side shows the time change of the heat signal of the heater corresponding to each nozzle in the nozzle row. As described above, the nozzles divided into 16 sections in units of 8 are further divided into 8 drive blocks Bi (i = 1 to 8) for each section. Each heater is driven in units of blocks. Specifically, the nozzle with the earliest arrangement order in the section, for example, the nozzle 1 in the first section and the nozzle 9 in the second section become the same drive block 1. Accordingly, the heaters corresponding to the nozzle 1 and the nozzle 9 respectively receive the heat signal at the same timing, so that the nozzle 1 and the nozzle 9 eject ink droplets at the same timing.
[0042]
At the time of recording, these blocks are sequentially driven from the block 1. The time interval Tb of the drive block is determined from the drive frequency fop.
Tb ≒ 1 / fop / Ndiv
It is determined. When ink droplets are ejected at this time interval, the position interval of the ink droplets at a certain time is as shown on the right side in FIG.
[0043]
It has been confirmed by experiments by the inventors that in such a separate divided drive type recording head, if only the time interval is shortened without changing the drive frequency, crosstalk becomes more intense and meniscus surface vibration becomes more intense. .
[0044]
FIG. 5 is a diagram illustrating a timing table of the heat signal of each heater when the block driving time interval is shortened. The block time interval is set to a time Tb ′ (Tb ′ <Tb) shorter than the time interval Tb during normal recording, and the drive frequency is the same as during normal recording. In the same figure, as can be seen from the position interval of the ink droplets at a certain time on the right side, the difference in ejection time between the adjacent nozzles in each section is shortened as the time interval is shortened.
[0045]
Therefore, in this embodiment, this phenomenon is used at the time of preliminary ejection. In other words, during normal recording, the block time interval is driven by Tb, and recording is performed with crosstalk suppressed. On the other hand, at the time of preliminary ejection, the block time interval is driven by Tb ′, and ink droplets are ejected in a state where crosstalk is more intense. As a result, the ink viscosity in the vicinity of the ejection port is reduced due to the intense crosstalk phenomenon, and effective preliminary ejection can be performed with a small amount of ink consumption.
[0046]
(Embodiment 3)
The ink is relatively hard to thicken at higher temperatures. Therefore, if the inside of the nozzle is always kept at a certain temperature, it is difficult for the ink to thicken and the deterioration of the ink state in the vicinity of the ejection port can be prevented.
[0047]
Therefore, in the present embodiment, a method will be described in which the heater is energized with a voltage that does not eject ink while ink is not ejected to keep the ink in the nozzles warm.
[0048]
The configuration of the ink jet recording apparatus of the present embodiment is the same as that of the first embodiment.
[0049]
If a drive signal is not input to the heater for a predetermined time or more, it is determined that the nozzle does not perform a discharge operation, and the heater is energized at a lower voltage than during discharge. This energization operation may be performed continuously at a low voltage that does not discharge ink, or may be performed at regular time intervals. Furthermore, the form which maintains the state which is not discharged by changing the space | interval of the pulse provided to a heater, or changing a voltage may be sufficient. It should be noted that if the temperature of the ink and the recording head is too high, the discharge pressure will change and the characteristics during ink discharge will be unstable, so a limit function is provided so that the temperature of the ink does not exceed a predetermined temperature. It is also effective.
[0050]
Further, it is more effective if the means for keeping the temperature of ink in the present embodiment in combination with the first or second embodiment when not ejected.
[0051]
(Other)
The present invention includes a means (for example, an electrothermal converter or a laser beam) that generates thermal energy as energy used for ejecting ink, particularly in the ink jet recording system, and the ink is generated by the thermal energy. In the recording head and the recording apparatus of the type that causes the state change, excellent effects are brought about. This is because such a system can achieve higher recording density and higher definition.
[0052]
As for the typical configuration and principle, for example, those performed using the basic principle disclosed in US Pat. Nos. 4,723,129 and 4,740,796 are preferable. This method can be applied to both the so-called on-demand type and the continuous type. In particular, in the case of the on-demand type, it is arranged corresponding to the sheet or liquid path holding the liquid (ink). By applying at least one drive signal corresponding to the recorded information and giving a rapid temperature rise exceeding nucleate boiling to the electrothermal transducer, the thermal energy is generated in the electrothermal transducer, and the recording head This is effective because film boiling occurs on the heat acting surface of the liquid and, as a result, bubbles in the liquid (ink) corresponding to the drive signal on a one-to-one basis can be formed. By the growth and contraction of the bubbles, liquid (ink) is ejected through the ejection opening to form at least one droplet. It is more preferable that the drive signal has a pulse shape, since the bubble growth and contraction is performed immediately and appropriately, and thus it is possible to achieve discharge of a liquid (ink) having particularly excellent responsiveness. As this pulse-shaped drive signal, those described in US Pat. Nos. 4,463,359 and 4,345,262 are suitable. Further excellent recording can be performed by employing the conditions described in US Pat. No. 4,313,124 of the invention relating to the temperature rise rate of the heat acting surface.
[0053]
As the configuration of the recording head, in addition to the combination configuration (straight liquid channel or right angle liquid channel) of the discharge port, the liquid channel, and the electrothermal transducer as disclosed in each of the above-mentioned specifications, the heat acting part The configurations using US Pat. No. 4,558,333 and US Pat. No. 4,459,600, which disclose the configuration in which the lens is disposed in the bending region, are also included in the present invention. In addition, for a plurality of electrothermal transducers, Japanese Patent Application Laid-Open No. Sho 59-123670 that discloses a configuration in which a common slit is used as a discharge portion of the electrothermal transducer or an aperture that absorbs pressure waves of thermal energy is provided. The effect of the present invention is also effective as a configuration based on Japanese Patent Application Laid-Open No. 59-138461 which discloses a configuration corresponding to the discharge unit. That is, whatever the form of the recording head is, according to the present invention, recording can be performed reliably and efficiently.
[0054]
Furthermore, the present invention can be effectively applied to a full-line type recording head having a length corresponding to the maximum width of a recording medium that can be recorded by the recording apparatus. As such a recording head, either a configuration satisfying the length by a combination of a plurality of recording heads or a configuration as a single recording head formed integrally may be used.
[0055]
In addition, even the serial type as shown in the above example can be connected to the main body of the recording head or attached to the main body of the device so that electrical connection with the main body of the device and ink supply from the main body are possible. The present invention is also effective when a replaceable chip type recording head or a cartridge type recording head in which an ink tank is integrally provided in the recording head itself is used.
[0056]
In addition, it is preferable to add a recording head ejection recovery means, a preliminary auxiliary means, and the like as the configuration of the recording apparatus of the present invention, since the effects of the present invention can be further stabilized. Specifically, heating is performed using a capping unit, a cleaning unit, a pressurizing or suction unit, an electrothermal transducer, a heating element different from this, or a combination thereof. Examples thereof include a preliminary heating unit for performing the discharge and a preliminary discharge unit for performing discharge different from the recording.
[0057]
Also, regarding the type or number of recording heads to be mounted, for example, a plurality of recording heads are provided corresponding to a plurality of inks having different recording colors and densities, in addition to one provided corresponding to a single color ink. May be used. That is, for example, as a recording mode of the recording apparatus, not only a recording mode of only a mainstream color such as black, but also a recording head may be configured integrally or by a combination of a plurality of different colors, Alternatively, the present invention is extremely effective for an apparatus having at least one of full-color recording modes by color mixing.
[0058]
In addition, in the embodiments of the present invention described above, the ink is described as a liquid. However, ink that is solidified at room temperature or lower and that softens or liquefies at room temperature may be used. In the ink jet method, the temperature of the ink itself is generally adjusted within a range of 30 ° C. or higher and 70 ° C. or lower to control the temperature of the ink so that it is in the stable discharge range. A liquid material may be used. In addition, it is solidified and heated in an untreated state in order to actively prevent the temperature rise caused by thermal energy from being used as the energy for changing the state of the ink from the solid state to the liquid state, or to prevent the ink from evaporating. You may use the ink which liquefies by. In any case, by applying thermal energy according to the application of thermal energy according to the recording signal, the ink is liquefied and liquid ink is ejected, or when it reaches the recording medium, it already starts to solidify. The present invention can also be applied to the case where ink having a property of being liquefied for the first time is used. The ink in such a case is in a state of being held as a liquid or a solid in a porous sheet recess or through-hole as described in JP-A-54-56847 or JP-A-60-71260. Alternatively, the electrothermal converter may be opposed to the electrothermal converter. In the present invention, the most effective one for each of the above-described inks is to execute the above-described film boiling method.
[0059]
In addition, the ink jet recording apparatus according to the present invention may be used as an image output terminal of an information processing device such as a computer, a copying apparatus combined with a reader or the like, and a facsimile apparatus having a transmission / reception function. The thing etc. may be sufficient.
[0060]
【The invention's effect】
By using the present invention, ink droplets are ejected only from some of the plurality of ejection ports, the meniscus surface of the ejection port is vibrated, and the high-viscosity ink near the ejection port and the vicinity of the common liquid chamber By mixing ink with low viscosity, when ink is ejected from the remaining ejection ports that were not ejected in the ejection operation, ink with high viscosity can be effectively discharged, and the state in the vicinity of the ejection ports can be reduced. Make it good. Accordingly, it is possible to suppress the wasteful consumption of ink in the preliminary ejection and maintain the nozzle state in which the ink droplets can be ejected constantly and stably.
[0061]
Also, Give a heat signal to each drive block In the recording head of the type, the block drive interval for preliminary ejection is set to a time interval shorter than the block drive interval for recording, so that the vibration of the meniscus surface is increased, so that highly viscous ink is effectively discharged. can do.
[0062]
Further, at the time of non-recording, it is possible to prevent the ink from being thickened by keeping the temperature in the vicinity of the ejection port so as not to eject the ink.
[Brief description of the drawings]
FIGS. 1A and 1B are schematic views showing a state in the vicinity of a discharge port, where FIG. 1A is a state before vibration is applied to a meniscus surface, and FIGS. 1B to 1D are views after vibration is applied to the meniscus surface; It is a figure which shows the mode of a change of.
FIG. 2 is a perspective view showing an ink jet recording apparatus of the present embodiment.
FIG. 3 is a diagram showing a change in position of a meniscus surface of a nozzle that is not driven when an adjacent nozzle is driven.
FIG. 4 is a diagram illustrating a timing table of a heat signal of a heater of a recording head during recording.
FIG. 5 is a diagram illustrating a timing table of a heat signal of a recording head heater during preliminary ejection.
[Explanation of symbols]
21 Recording head unit
22 Carriage
23 Guidelines
24 Transport roller
25 Pre-discharge cap
26 blade

Claims (6)

A plurality of discharge ports arranged in the recording head are divided into a plurality of drive blocks as a set of discharge ports that are simultaneously driven every predetermined number , and a heat signal given to each of the drive blocks is divided at a predetermined time interval. An inkjet recording apparatus that ejects ink droplets onto a recording medium by applying a heat signal to each ejection port at a predetermined driving frequency while switching ,
During the preliminary ejection, with switches at the time interval shorter than a predetermined time interval during a heat signal of normal recording to be supplied to each of the drive block, the predetermined driving frequency at the time of recording in each outlet An ink jet recording apparatus comprising: preliminary discharge means for discharging ink droplets when a heat signal is given at a timing equal to . The recording head includes an electrothermal transducer corresponding to each discharge port,
2. The ink jet recording apparatus according to claim 1, wherein a predetermined amount of ink droplets is ejected by the generation pressure of bubbles formed in the ink by the heat generated by the electrothermal transducer.   3. The apparatus according to claim 2, further comprising a heat retaining unit that retains the ink in the vicinity of the ejection port by applying electric energy to the electrothermal transducer so that the recording head does not eject ink droplets during non-recording. The ink jet recording apparatus described. A heat signal to be given to each of the drive blocks is determined in advance using an inkjet recording apparatus having a plurality of drive blocks as a set of discharge ports in which a plurality of discharge ports arranged in the recording head are simultaneously driven every predetermined number. An inkjet recording method for ejecting ink droplets onto a recording medium by applying a heat signal to each ejection port at a predetermined driving frequency while switching at a given time interval,
During the preliminary ejection, with switches at the time interval shorter than a predetermined time interval during a heat signal of normal recording to be supplied to each of the drive block, the predetermined driving frequency at the time of recording in each outlet An ink jet recording method comprising a preliminary ejection step of ejecting ink droplets when a heat signal is given at a timing equal to .   The recording head includes an electrothermal transducer corresponding to each ejection port, and discharges a predetermined amount of ink droplets by the generation pressure of bubbles formed in the ink by the heat generated by the electrothermal transducer. The ink jet recording method according to claim 4.   6. The apparatus according to claim 5, further comprising a heat retaining unit that retains the ink in the vicinity of the ejection port by applying electric energy to the electrothermal transducer so that the recording head does not eject ink droplets during non-recording. The inkjet recording method as described.

Images