JP2004351865A - Inkjet storage device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a means of avoiding an irregular consistency of ink which is allowed to stand in an ink container for a long period of time appearing as the irregular consistency of a storage image. <P>SOLUTION: The problem of an irregular consistency that generates a precipitation phenomenon of a pigment can be solved without adding a special construction to an exchange type ink tank which is a consumption member, since the ink flow in the ink tank can be generated and stirred by equipping a mutually circulating pump, etc. for mutually circulating through more than two communication openings in communication with the inside of an ink tank when providing the ink tank to the device body. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an ink supply device that supplies ink to a recording head used in an ink jet recording device, and an ink jet recording device provided with the device.
[0002]
[Prior art]
Ink-jet printing is a method in which an image is formed by discharging ink of a plurality of colors prepared corresponding to a single color or color printing onto various printing media such as paper, cloth, nonwoven fabric, and plastic films for OHP. Is the way. An ink jet printing apparatus adopting this method includes a carriage which is provided with a printing means (print head) and an ink tank as an ink supply means and is main-scanned in a predetermined direction with respect to a print medium, and is adapted to move the print medium in the main scanning direction. Is provided with transport means for transporting (sub-scanning) in different directions, and control means for controlling these, so that the print head is serially scanned in the main scanning direction while a plurality of ink ejection ports provided in the print head are provided. There is a type in which ink is ejected, and on the other hand, printing is sequentially performed on a print medium by carrying a predetermined amount (for example, a print width in one serial scan corresponding to an ejection port arrangement range) after a serial scan. In such an ink-jet printing method, a so-called drop-on-demand method in which ink is directly discharged onto a print medium in accordance with a print signal to perform printing is employed, which provides an easy and inexpensive recording (printing) method. It has been widely adopted.
[0003]
By the way, in the ink jet printing apparatus as described above, an ink tank is provided as a cartridge integrally with or separately from a print head on a carriage, and when the ink remaining amount is exhausted, the ink tank is replaced with a new cartridge. The type in which ink is replenished (cartridge replacement method) is most generally and widely known.
[0004]
However, when an extremely high print duty is required, such as when an inkjet printing apparatus is used for industrial purposes such as printing or textile printing, the ink consumption is very large, so a cartridge replacement ink tank is mounted on the carriage. In such a method, the mass of the ink tank must be increased, and it is difficult to achieve high-speed printing by high-acceleration / deceleration carriage scanning with a low-cost carriage driving motor or the like.
[0005]
In order to solve this problem, a method is adopted in which an ink tank having a necessary and sufficient capacity is arranged at a position where it does not move except on the carriage, and a tube etc. is connected to the recording head on the carriage and various types of pumps are used to supply it. General. (For example, see Patent Document 1.)
[Patent Document 1]
JP-A-2002-30771
[0006]
[Problems to be solved by the invention]
However, in the ink container configured as described above, there is no problem in the case where the ink using the coloring agent containing the dye as a main component is contained, but in the case where the ink using the pigment as the coloring agent is contained, When the pigment is stored for a long period of time, the pigment sediments, and density unevenness occurs in the ink in the ink container, where the density varies depending on the region.
[0007]
Usually, pigment ink is obtained by mixing a water-insoluble coloring agent with a polymer resin or a so-called surfactant type dispersant, finely crushing the mixture, and diluting the mixture with water, oil, or other solvent components. Since the pigment particles themselves do not dissolve in water, when applied to printed matter, pigment inks have better water resistance than dye inks. Further, since the pigment particles are strong against light, they do not fade even when exposed to light for a long period of time, and exhibit particularly excellent performance, for example, in printed matter for long-term display. It is for this reason that pigment inks are widely used in general printed matter. However, solid fine particles such as pigments are suspended in liquid as fine particles, but if the specific gravity is larger than that of the solvent liquid (medium), sedimentation is inevitable.
[0008]
In addition to the sedimentation effect caused by gravity, the pigment particles are continually performing Brownian motion under the influence of thermal motion of the medium molecules. This Brownian motion causes diffusion, which is the opposite of sedimentation. The concentration distribution in the vertical direction of the pigment ink contained in the ink container is determined by the sedimentation action and the diffusion action by Brownian motion.
[0009]
Therefore, when the ink container is left standing for a long time with the ink supply port directed downward in the vertical direction, inks having different densities flow toward the nozzles of the recording head along the vertical direction. When the ink density at the ink supply port is different as described above, a density difference occurs between the inks ejected from the nozzles of the nozzle row, resulting in printing unevenness in printing.
[0010]
Further, when an ink tank is mounted on the carriage, the agitating effect is generated by the scanning movement and density unevenness can be prevented. However, as described above, the ink tank is mounted in a place where the large-capacity ink tank does not move. In general, it was necessary to improve the density unevenness.
[0011]
The present invention has been made in view of the above technical problems, and it is an object of the present invention to prevent the density unevenness of ink stored in an ink container left for a long time from appearing as the density unevenness of a recorded image. It is an object of the present invention to provide an ink jet recording apparatus capable of performing the following.
[0012]
[Means for Solving the Problems]
In order to solve the above-mentioned problem, in the ink jet recording apparatus according to the present invention, in which a large-capacity ink tank is mounted in a place where the ink tank is not moved, when two or more communication ports communicating with the inside of the ink tank are installed when the main body is installed. By providing a pump or the like that circulates, it is possible to eliminate the density unevenness caused by the sedimentation phenomenon of the pigment. Hereinafter, specific examples of the present invention will be described.
[0013]
BEST MODE FOR CARRYING OUT THE INVENTION
(First embodiment)
FIG. 1 is a perspective view illustrating a schematic configuration of an inkjet recording apparatus according to an embodiment of the present invention. The ink jet recording apparatus of the present embodiment repeats the reciprocating movement (main scanning) of the recording head 201 and the conveyance (sub-scanning) of the recording sheet S such as general recording paper, special paper, and OHP film at a predetermined pitch. This is a serial type recording apparatus that forms characters, symbols, images, and the like by selectively ejecting ink from the recording head 201 in synchronization with these movements and attaching the ink to the recording sheet S.
[0014]
In FIG. 1, a recording head 201 is detachably mounted on a carriage 202 slidably supported by two guide rails and reciprocated along the guide rails by driving means such as a motor (not shown). The recording sheet S faces the ink ejection surface of the recording head 201 by the transport roller 203 and intersects with the moving direction of the carriage 202 (for example, in a direction intersecting the moving direction of the carriage 202 so as to maintain a constant distance from the ink ejection surface). It is conveyed in the direction of arrow A which is a direction orthogonal to the direction.
[0015]
The recording head 201 has a plurality of nozzle rows that eject ink of different colors (for example, four colors of black, cyan, magenta, and yellow). This nozzle row is substantially orthogonal to the main scanning direction. A plurality of independent main tanks (ink tanks) 204 are detachably mounted on the ink supply unit 205 in accordance with the color of ink ejected from the recording head 201. The ink supply unit 205 and the recording head 201 are connected by a plurality of ink supply tubes 206 each corresponding to the color of the ink, and are housed in the main tank 204 by mounting the main tank 204 to the ink supply unit 205. Each color ink can be supplied independently to each nozzle row of the recording head 201.
[0016]
A recovery unit 207 is disposed so as to face the ink ejection surface of the recording head 201 in a non-recording area which is an area within the reciprocating movement range of the recording head 201 and outside the passing range of the recording sheet S. I have. The recovery unit 207 is a mechanism that forcibly sucks ink, bubbles, and the like from the ejection nozzles of the recording head 201 and performs cleaning of the nozzles.
[0017]
Next, the basic principle of ink supply in this ink jet recording apparatus will be briefly described with reference to FIG.
[0018]
The recording head 201 and the main tank 204 are connected by an ink supply tube 206 to form an ink path. This ink path is filled with the ink 209, and the print head 201 is arranged so that the position of the nozzle 201g is higher than the liquid level of the main tank 204 by the height H. Is maintained at a negative pressure. Due to this negative pressure, the state where the meniscus of the ink is formed at the tip of the nozzle 201g of the recording head 201 is maintained. This prevents leakage of ink from the nozzle 201g and entry of air. When the ink is ejected from the nozzle 201g, the ink amount in the recording head 201 decreases, the negative pressure temporarily increases, and the meniscus recedes. However, the ink is filled in the nozzle 201g again by the capillary force of the nozzle 201g, The ink 209 is sucked up from the main tank 204 via the ink supply tube 206, so that the pressure in the recording head 201 returns to its original state, and the meniscus is stabilized at the tip of the nozzle 201g. Such ejection and ink supply (refilling) are repeated. The ink jet recording apparatus according to the present embodiment is based on this basic principle.
[0019]
Next, a detailed configuration of an ink supply system of the inkjet recording apparatus will be described with reference to FIG. FIG. 3 is a diagram for explaining an ink supply path of the ink jet recording apparatus shown in FIG. 1, and for simplification of description, only a path for one color is shown.
[0020]
First, the recording head 201 will be described. Ink is supplied to the recording head 201 from a connector insertion port 201 a to which a liquid connector provided at the tip of the ink supply tube 206 is airtightly connected. The connector insertion port 201a communicates with a sub-tank (first liquid chamber) 201b formed above the recording head 201. A liquid chamber (second liquid chamber) 201f for directly supplying ink to a nozzle section having a plurality of nozzles 201g arranged in parallel is formed below the sub-tank section 201b in the direction of gravity. The sub-tank portion 201b and the liquid chamber 201f are partitioned by a filter 201c. The sub-tank portion 201b and the liquid chamber 201f have a partition portion 201e having an opening 201d formed at a boundary between the sub-tank portion 201b and the liquid chamber 201f. 201e.
[0021]
With the above-described configuration, the ink supplied from the connector insertion port 201a to the recording head 201 is supplied to the nozzle 201g via the sub tank 201b, the filter 201c, and the liquid chamber 201f. The space from the connector insertion opening 201a to the nozzle 201g is kept airtight with respect to the atmosphere.
[0022]
An opening is formed on the upper surface of the sub tank 201b, and the opening is covered with a dome-shaped elastic member 201h. The space surrounded by the elastic member 201h is a pressure adjustment chamber 201i, which has a function of changing the volume according to the pressure in the sub tank 201b and adjusting the pressure in the sub tank 201b as described later.
[0023]
The nozzle 201g has a cylindrical structure with a cross-sectional width of about 20 μm, and discharges ink from the nozzle 201g by applying discharge energy to the ink in the nozzle 201g. After discharging the ink, the nozzle 201g is formed by the capillary force of the nozzle 201g. Is filled with ink. Normally, this ejection is repeated at a cycle of 20 kHz or more to perform fine and high-speed image formation. In order to give ejection energy to the ink in the nozzle 201g, the recording head 201 has an energy generating unit for each nozzle 201g. In the present embodiment, a heating resistor for heating the ink in the nozzle 201g is used as the energy generating means, and the heating resistor is selected by a command from a head control unit (not shown) for controlling the driving of the recording head 201. And the ink in the desired nozzle 201g is film-boiling, and the ink is ejected from the nozzle 201g by utilizing the pressure of the bubble generated thereby.
[0024]
The nozzle 201g is arranged with the tip for discharging ink facing downward, but is not provided with a valve mechanism for closing the tip, and the ink fills the nozzle 201g with a meniscus formed. Therefore, the inside of the recording head 201, particularly the inside of the nozzle 201g, is kept in a negative pressure state. However, if the negative pressure is too small, when foreign matter or ink adheres to the tip of the nozzle 201g, the meniscus of the ink may collapse and the ink may leak from the nozzle 201g. On the other hand, if the negative pressure is too large, the force for pulling the ink back into the nozzle 201g becomes stronger than the energy given to the ink at the time of ejection, resulting in ejection failure. Therefore, the negative pressure in the nozzle 201g is kept in a certain range slightly lower than the atmospheric pressure. The range of the negative pressure varies depending on the number of nozzles 201g, the sectional area, the performance of the heating resistance element, and the like. According to the experimental results of the present inventors, -40 mmAq (about -0.0040 atm = -4.053 kPa). A range of -200 mmAq (about -0.0200 atm = -2.0265 kPa) (however, the specific gravity of the ink / the specific gravity of water) is preferable.
[0025]
In the present embodiment, the ink supply unit 205 and the recording head 201 are connected by the ink supply tube 206, and the position of the recording head 201 with respect to the ink supply unit 205 can be set relatively freely. The recording head 201 is arranged at a position higher than the ink supply unit 205 in order to reduce the pressure.
[0026]
The filter 201c prevents foreign matter that may clog the nozzle 201g from flowing out of the sub tank 201b into the liquid chamber 201f. The area of the filter 201c is set so that the pressure loss due to the ink is equal to or less than an allowable value. The pressure loss increases as the mesh of the filter 201c becomes finer and the flow rate of ink increases, and is inversely proportional to the area of the filter 201c. In recent years, in a high-speed, multi-nozzle, small-dot printing apparatus, pressure loss tends to be high, and a large filter 201c having a size of about 10 × 20 mm is used. A large space is also required for the liquid chamber 201f downstream of the sub tank 201b and the filter 201c. The ink in the sub tank 201b is in contact with the upper surface of the filter 201c, and the area in contact with the ink is the effective area of the filter 201c. The pressure loss due to the filter 201c depends on the effective area of the filter 201c. In the present embodiment, the filter 201c is arranged so as to be horizontal when the recording head 201 is used, and the ink is brought into contact with the entire upper surface of the filter 201c to maximize the effective area of the filter and reduce the pressure loss. .
[0027]
When the filter 201c comes into contact with the ink, the ink penetrates into each hole (mesh) due to the capillary force to form a fine meniscus, and the ink easily permeates, but the air circulation becomes difficult. Have. The finer the mesh, the higher its meniscus strength and the more difficult it is to pass air.
[0028]
In the filter 201c of the present embodiment, the pressure required to transmit air is about 0.1 atm (10.1325 kPa) (experimental value). Therefore, if air exists in the liquid chamber 201f located downstream of the filter 201c with respect to the direction of movement of the ink in the recording head 201, the air cannot pass through the filter 201c with the buoyancy of the air itself. The air inside remains in the liquid chamber 201f. In the present embodiment, this phenomenon is utilized, and the liquid chamber 201f is not filled with ink, and an air layer exists between the ink in the liquid chamber 201f and the filter 201c. A predetermined amount of ink is stored in the liquid chamber 201f so as to separate the ink from the filter 201c.
[0029]
Further, if air from the liquid chamber 201f enters the nozzle 201g, the ink is not replenished to the nozzle 201g after the ink is ejected, and an ejection failure occurs. Therefore, the inside of the nozzle 201g needs to be always filled with the ink.
[0030]
The pressure adjustment chamber 201i is a chamber whose volume decreases as the internal negative pressure increases. When the pressure adjustment chamber 201i is formed of the elastic member 201h as in the present embodiment, a rubber material is used as the elastic member 201h. And the like are preferably used.
[0031]
When the pressure adjustment chamber 201i is not provided, the pressure in the sub tank 201b is directly affected by the resistance due to the pressure loss when the ink passes through the main tank 204, the ink supply unit 205, and the ink supply tube 206. Therefore, in the case of a so-called high duty in which ink is ejected at a high rate, such as ejecting ink from all the nozzles 201g, the amount of ink supplied to the recording head 201 becomes insufficient for the ejected ink, and the negative pressure Rises sharply. When the negative pressure of the nozzle 201g exceeds the above-mentioned limit value of -200 mmAq (about -2.0265 kPa), the ejection becomes unstable, and an inconvenient state occurs in image formation.
[0032]
In a serial type recording apparatus as in the present embodiment, there is a state in which the ejection of ink is interrupted when the carriage 202 (see FIG. 1) is inverted, even when an image is formed at a high duty. The pressure adjustment chamber 201i plays a role of a capacitor, such as reducing the volume during ejection of ink to mitigate a rise in negative pressure in the sub-tank portion 201b and restoring the ink at the time of inversion.
[0033]
Next, the ink supply unit 205 and the main tank 204 will be described.
[0034]
The main tank 204 is configured to be detachable from the ink supply unit 205, and has an ink supply port sealed with a rubber stopper 204b and an air introduction port sealed with a rubber stopper 204c at the bottom of a rigid tank body. And The main tank 204 is an airtight container by itself, and the ink 209 is stored in the main tank 204 as a liquid.
[0035]
On the other hand, the ink supply unit 205 has an ink supply needle 205a for taking out the ink 209 from the main tank 204 and an air introduction needle 205b for introducing the atmosphere into the main tank 204. The ink supply needle 205a and the air introduction needle 205b are both hollow needles, and are arranged with their needle tips facing up corresponding to the positions of the ink supply port and the air introduction port of the main tank 204. By being attached to the ink supply unit 205, the ink supply needle 205a and the air introduction needle 205b pass through the rubber plugs 204b and 204c, respectively, and enter the inside of the main tank 204.
[0036]
The ink supply needle 205a is connected to the ink supply tube 206 via a path including a liquid path 205c, a shutoff valve 210, and a liquid path 205d. The atmosphere introduction needle 205b communicates with the atmosphere via the liquid path 205e, the buffer chamber 205f, and the atmosphere communication port 205g. In the present embodiment, the ink supply needle 205a and the air introduction needle 205b have a large inner diameter of 1.6 mm in order to suppress the flow resistance of the ink.
[0037]
In addition, the liquid path 205i branches from the middle of the liquid path 205c. At the same time, a liquid path 205j branches off from the middle of the liquid path 205e and is connected to a circulation pump 205k. The operation of the circulation pump 205k allows the ink to be sent bidirectionally. When this pump does not operate, it rotates while pressing the tube with a rotating roller to prevent free ink flow.For example, a tube pump is optimal. Alternatively, a shutoff valve (not shown) may be additionally provided in the liquid passage 205i or the liquid passage 205j.
[0038]
The shutoff valve 210 has a diaphragm 210a made of a rubber material, and opens and closes the two liquid paths 205c and 205d by displacing the diaphragm 210a. A cylindrical spring holder 210b holding a pressing spring 210c inside is attached to the upper surface of the diaphragm 210a, and the liquid passage 205c, 205d is cut off. The spring holder 210b has a flange with which a lever 210d operated by a link 207e of the recovery unit 207 described later is engaged. By operating the lever 210d and lifting the spring holder 210b against the spring force of the pressing spring 210c, the liquid paths 205c and 205d communicate with each other. The shut-off valve 210 is opened when the recording head 201 is ejecting ink, closed during standby and pause, and opened and closed in synchronization with the recovery unit 207.
[0039]
Except for the lever 210d, the configuration of the ink supply unit 205 described above is provided for each main tank 204, that is, for each ink color (in this embodiment, four colors of black, cyan, magenta, and yellow). The lever 210d is common to all colors, and simultaneously opens and closes the shutoff valves 210 for all colors.
[0040]
With the above configuration, when the ink in the recording head 201 is consumed, the ink is supplied from the main tank 204 to the recording head 201 via the ink supply unit 205 and the ink supply tube 206 as needed due to the negative pressure. At this time, the same amount of air as the ink supplied from the main tank 204 is introduced into the main tank 204 from the air communication port 205g through the buffer chamber 205f and the air introduction needle 205b.
[0041]
The buffer chamber 205f is a space for temporarily holding ink flowing out of the main tank 204 due to expansion of air in the main tank 204, and the lower end of the air introduction needle 205b is located at the bottom of the buffer chamber 205f. . When the air in the main tank 204 expands, for example, when the ambient temperature rises or the outside air pressure drops while the inkjet recording apparatus is on standby or stopped, the shutoff valve 210 is closed. The ink 209 flows from the air introduction needle 205b to the buffer chamber 205f via the liquid path 205e. Conversely, when the air in the main tank 204 contracts, such as when the environmental temperature decreases, the ink that has flowed into the buffer chamber 205f returns to the main tank 204. When ink is ejected from the print head 201 in a state where ink is present in the buffer chamber 205f, first, the ink in the buffer chamber 205f returns to the main tank 204, and after the ink in the buffer chamber 205f is exhausted, Air is introduced into the main tank 204.
[0042]
The volume Vb of the buffer chamber 205f is set so as to satisfy the usage environment of the product. For example, if the product is intended to be used within a temperature range of 5 ° C. (278 K) to 35 ° C. (308 K), assuming that the capacity of the main tank 204 is 100 ml, Vb = 100 × (308-278) / 308. = 9.7 ml or more.
[0043]
A circuit 205h for measuring the electric resistance of the ink is connected to the ink supply needle 205a and the air communication needle 205b, and the presence or absence of the ink in the main tank 204 can be detected. This circuit 205h detects an electric close because current flows through the circuit 205h through the ink in the main tank 204 when ink is present in the main tank 204, and detects the absence of ink or the main tank 204. In the state where is not mounted, an electrical open is detected. Since the detection current is weak, it is important to insulate the ink supply needle 205a from the air introduction needle 205b. In the present embodiment, the path from the ink supply needle 205a to the recording head 201 and the air communication needle 205b from the atmosphere communication needle 205b are connected to the atmosphere. The path to the opening 205g is completely independent so that the electric resistance of only the ink in the main tank 204 can be measured.
[0044]
Next, a method of eliminating the uneven density caused by the sedimentation phenomenon of the pigment in the above configuration will be described. First, when the sedimentation phenomenon of the pigment occurs or is estimated, the above-described lever 210d is operated to lower the spring holder 210b using the spring force of the pressing spring 210c, thereby shutting off the liquid passages 205c and 205d. . Subsequently, the circulation pump 205k is operated to send ink in a predetermined direction. The direction of liquid supply at this time is arbitrary, but it is more effective to select a direction with a higher ink stirring effect in the main tank 204. One end is open to the atmosphere via an air communication port 205g, but the other liquid paths 205i and 205j, the ink supply needle 205a, the air introduction needle 205b, the circulation pump 205k, and the liquid path of the main tank 204 are sealed. Therefore, ink does not overflow from the air communication port 205g due to the operation of the circulation pump 205k. The opening in the main tank of the ink supply needle 205a or the air introduction needle 205b is located at the bottom of the main tank 204 when the main tank 204 is inserted, so that the ink near the bottom where the density is highest due to the sedimentation phenomenon is caused by the ink flow by the operation of the circulation pump 205k. The ink can be sucked out from one opening and ejected from the other opening, and the stirring of the ink 209 in the main tank 204 can be promoted to achieve a uniform density.
[0045]
(Second embodiment)
FIG. 4 is a second embodiment of the drawing for describing the ink supply path of the ink jet recording apparatus shown in FIG. 1, and only a path for one color is shown for simplification of description.
[0046]
In this embodiment, a piston 205m is provided instead of the circulation pump in the first embodiment. The interior of the piston 205m is separated into two liquid chambers via the piston, and is connected to liquid paths 205i and 205j, respectively. The piston can reciprocate by an external power (not shown).
[0047]
When the sedimentation phenomenon of the pigment occurs or is estimated, the above-described lever 210d is operated to lower the spring holder 210b using the spring force of the pressing spring 210c, thereby shutting off the liquid paths 205c and 205d. Subsequently, by reciprocating the piston 205m, the ink is repeatedly ejected and sucked from the ink supply needle 205a and the air introduction needle 205b, thereby agitating the ink in the main tank.
[0048]
Here, since it is preferable that air does not enter the liquid paths 205i and 205j and the piston 205m as much as possible, the liquid path is filled with ink in advance, or the piston position is initially set to the liquid path 205i side dead center, and the operation is performed. By starting, much air inflow can be prevented.
[0049]
(Other)
In addition, the present invention includes a means (for example, an electrothermal converter or a laser beam) for generating thermal energy as energy used for causing ink to be ejected, particularly in an ink jet recording method. The present invention brings about an excellent effect in a recording head and a recording apparatus of a type that causes a change in the state. This is because according to such a method, it is possible to achieve higher density and higher definition of recording.
[0050]
Regarding the typical configuration and principle, it is preferable to use the basic principle disclosed in, for example, US Pat. Nos. 4,723,129 and 4,740,796. . 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 a sheet or a liquid path holding a liquid (ink). Applying at least one drive signal corresponding to the recording information and providing a rapid temperature rise exceeding nucleate boiling to the electrothermal transducer, thereby generating heat energy in the electrothermal transducer, and thereby forming a recording head. This is effective because film boiling occurs on the heat-acting surface of the liquid, and as a result, air bubbles in the liquid (ink) corresponding to this drive signal one-to-one can be formed. By discharging the liquid (ink) through the discharge opening by the growth and contraction of the bubble, at least one droplet is formed. When the drive signal is formed into a pulse shape, the growth and shrinkage of the bubble are performed immediately and appropriately, so that the ejection of the liquid (ink) having particularly excellent responsiveness can be achieved, which is more preferable. As the pulse-shaped drive signal, those described in U.S. Pat. Nos. 4,463,359 and 4,345,262 are suitable. Further, when the conditions described in US Pat. No. 4,313,124 relating to the temperature rise rate of the heat acting surface are adopted, more excellent recording can be performed.
[0051]
As a configuration of the recording head, in addition to a combination configuration (a linear liquid flow path or a right-angle liquid flow path) of a discharge port, a liquid path, and an electrothermal converter as disclosed in each of the above-mentioned specifications, A configuration using U.S. Pat. No. 4,558,333 and U.S. Pat. No. 4,459,600 which disclose a configuration in which is disposed in a bending region is also included in the present invention. In addition, Japanese Unexamined Patent Application Publication No. 59-123670 discloses a configuration in which a common slit is used as a discharge portion of an electrothermal converter for a plurality of electrothermal converters, and an aperture for absorbing a pressure wave of thermal energy is provided. The effect of the present invention is effective even if the configuration is based on JP-A-59-138461, which discloses a configuration corresponding to a discharge unit. That is, according to the present invention, recording can be reliably and efficiently performed regardless of the form of the recording head.
[0052]
Further, 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 on which a recording apparatus can record. Such a recording head may have a configuration in which the length is satisfied by a combination of a plurality of recording heads, or a configuration as a single recording head integrally formed.
[0053]
In addition, even with the serial type printer as in the above example, the recording head fixed to the main unit or attached to the main unit enables electrical connection with the main unit and supply of ink from the main unit. 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 provided integrally with the recording head itself is used.
[0054]
Further, it is preferable to add ejection recovery means for the recording head, 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 on the recording head by using capping means, cleaning means, pressurizing or suction means, an electrothermal transducer or another heating element or a combination thereof. Pre-heating means for performing the pre-heating and pre-discharging means for performing a different discharging from the recording can be used.
[0055]
Regarding the type or number of print heads to be mounted, for example, in addition to one provided for single color ink, a plurality of print heads are provided corresponding to a plurality of inks having different print colors and densities. May be used. That is, for example, the printing mode of the printing apparatus is not limited to the printing mode of only the mainstream color such as black, but may be any of integrally forming the printing head or a combination of a plurality of printing heads. The present invention is also very effective for an apparatus provided with at least one of the recording modes of full color by color mixture.
[0056]
In addition, in the embodiments of the present invention described above, the ink is described as a liquid, but an ink that solidifies at room temperature or below and that softens or liquefies at room temperature may be used, or In general, in the ink jet method, the temperature of the ink itself is controlled within a range of 30 ° C. or more and 70 ° C. or less to control the temperature so that the viscosity of the ink is in a stable ejection range. A liquid may be used. In addition, in order to positively prevent temperature rise due to thermal energy by using it as energy for changing the state of the ink from a solid state to a liquid state, or to prevent ink from evaporating, the ink is solidified in a standing state and heated. May be used. In any case, the application of heat energy causes the ink to be liquefied by the application of the heat energy according to the recording signal, and the liquid ink to be ejected, or to the solidification of the ink when it reaches the recording medium. The present invention is also applicable to a case where an ink having a property of liquefying for the first time is used. In such a case, the ink is held in a state of being held as a liquid or solid substance in the concave portion or through hole of the porous sheet as described in JP-A-54-56847 or JP-A-60-71260. Alternatively, it may be configured to face the electrothermal converter. In the present invention, the most effective one for each of the above-mentioned inks is to execute the above-mentioned film boiling method.
[0057]
In addition, as the form of the ink jet recording apparatus of the present invention, in addition to a form used as an image output terminal of an information processing device such as a computer, a form of a copying apparatus combined with a reader or the like, and a facsimile apparatus having a transmission / reception function are adopted. Or the like.
[0058]
【The invention's effect】
As described above, according to the present invention, in an ink jet recording apparatus mounted in a place where a large-capacity ink tank does not move, two or more communication ports that communicate with the inside of the ink tank when the main body of the ink tank is installed. By providing a pump that circulates between each other, the ink flow in the ink tank can be generated and agitated by its operation, and the density caused by the sedimentation phenomenon of the pigment without adding a special configuration to the replaceable ink tank that is a consumable member Since unevenness can be eliminated, a low-cost ink tank can be provided.
[Brief description of the drawings]
FIG. 1 is a perspective view showing a schematic configuration of an inkjet recording apparatus according to an embodiment of the present invention.
FIG. 2 is an explanatory diagram of an ink supply principle of the ink jet recording apparatus shown in FIG.
FIG. 3 is a diagram illustrating a first embodiment for describing an ink supply path for one color in the inkjet recording apparatus illustrated in FIG. 1;
FIG. 4 is a diagram illustrating a second embodiment for describing an ink supply path for one color in the inkjet recording apparatus illustrated in FIG. 1;
[Explanation of symbols]
201 Recording head
201a Connector insertion slot
201b Sub-tank (first ink chamber)
201c filter
201d opening
201e partition
201f liquid chamber (second ink chamber)
201g discharge nozzle
201h elastic member
201i Pressure adjustment chamber
202 carriage
203 transport roller
204 Main tank (ink tank)
204b, 204c rubber stopper
205 ink supply unit
205a Ink supply needle
205b Air introduction needle
205c, 205d, 205e Fluid path
205f buffer room
205g atmosphere communication port
205h circuit
205i, 205j fluid path
205k circulation pump
205m piston
206 Ink supply tube
207 Recovery Unit
207e link
209 ink
210 shut-off valve
210a diaphragm
210b Spring holder
210c pressure spring
210d lever
S Recording sheet

Claims (7)

A print head that performs printing on a print medium by discharging ink from a plurality of discharge ports,
A carriage mounted with the recording head and reciprocally scanning on the recording medium,
A recording medium transport unit that transports the recording medium by a predetermined distance in a direction perpendicular to the scanning direction of the carriage each time the carriage reciprocates once over the recording medium;
An ink storage tank installed at a position that does not affect the reciprocating scanning of the carriage and the conveyance of the recording medium by the recording medium conveying means, and an ink supply needle and an air introduction needle inserted into the ink storage tank, respectively. An ink jet recording apparatus comprising a supply tube for supplying ink from the ink storage tank to the ink supply needle,
One end of the ink supply needle and one end of the air introduction needle are respectively discharged into the ink storage tank, and the other end is connected to a liquid sending member. From the ink supply needle and the air introduction needle in the ink storage tank, an equal amount of ink is generated by the operation of the liquid sending member, and an interpolated ink flow is generated in which one flows in and the other discharges. The ink jet recording apparatus according to claim 1, wherein The said liquid sending member is a tube pump which presses and rotates a tube with a roller, and circulates and sends ink from the ink supply needle side to the air introduction needle side or the opposite direction. The ink jet recording apparatus according to any one of claims 1 to 2. 2. The liquid supply member according to claim 1, wherein the liquid supply member is a piston member, and is a liquid supply member that alternately changes an ink liquid supply direction from the ink supply needle side to the air introduction needle side or the opposite direction. 3. 3. The ink jet recording apparatus according to any one of 2. A shut-off valve is provided on the way from the ink supply needle to the recording head via the supply tube, so as to block the ink flow due to the operation of the liquid sending member from reaching the recording head. The ink jet recording apparatus according to any one of claims 1 to 4, wherein 6. The ink jet recording apparatus according to claim 1, wherein the recording ink is a recording ink containing a pigment. 7. The recording head according to claim 1, further comprising an electrothermal converter for converting electrical energy into thermal energy, and ejecting the ink using film boiling generated in the ink by the thermal energy applied by the electrothermal converter. The inkjet recording apparatus according to any one of claims 1 to 7.

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