JP3788209B2 - Inkjet recording device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention includes a carriage on which a recording head and a sub tank are mounted, supplies ink to a sub tank from an ink supply source disposed on the apparatus main body side through an ink supply path, and uses the ink stored in the sub tank for the recording head. The present invention relates to an ink jet recording apparatus configured to supply.
[0002]
[Prior art]
A typical ink jet printer as an ink jet recording apparatus is configured to record images, characters, and the like by ejecting ink droplets onto a recording medium such as recording paper.
[0003]
A printer that supports large-format recording paper such as A0 and a printer that supports a relatively large amount of printing for business use requires a large amount of ink because it consumes a large amount of ink. In a printer that can perform color printing using ink, it is necessary to store ink for the number of colors. For this reason, an ink supply source such as an ink tank or an ink cartridge capable of storing a large amount of ink is disposed on the printer main body side, and the ink is supplied from the ink supply source to the recording head via the ink supply tube. ing.
[0004]
In this configuration, a sub tank is mounted on the carriage in order to stabilize the supply of ink to the recording head, and the ink supplied through the ink supply tube is temporarily stored in the sub tank and then supplied to the recording head. The sub tank absorbs ink pressure fluctuations accompanying the scanning of the carriage, and stabilizes the ink supply to the recording head.
[0005]
[Problems to be solved by the invention]
By the way, there are various types of inks used in printers, and one type of them is pigment-dispersed ink (hereinafter referred to as pigment ink). In this pigment ink, a pigment is used as a pigment, and the pigment is dispersed in an ink solvent. This pigment ink has the advantage of vivid color development, but has the problem that the pigment will settle if left for a long period of about 1 to 2 months.
[0006]
For this reason, if left in a stored state for a long period of time, the ink in the sub-tank has a density unevenness in which the ink in the sub-tank is thin on the upper side of the tank and darker on the lower side as the pigment settles. If such density unevenness occurs, an image having a color darker than usual is recorded at the initial stage of printing, and then the color of the image gradually becomes lighter.
[0007]
Furthermore, the pigment may aggregate due to sedimentation and the particle size may increase. If the particle size of the pigment becomes excessively large, the aggregated pigment may clog the filter in the sub tank, and the ink supply to the recording head may be cut off.
[0008]
The present invention has been made in view of such circumstances, and an object of the present invention is to prevent problems caused by the sedimentation of the pigment of the ink stored in the sub-tank, thereby stabilizing the recorded image and the recording head. Another object of the present invention is to provide an ink jet recording apparatus that can stabilize the ink supply.
[0009]
[Means for Solving the Problems]
The present invention has been proposed in order to achieve the above-mentioned object. According to the first aspect of the present invention, a recording head and a sub tank are mounted on a carriage that reciprocates in the main scanning direction, and is arranged on the apparatus main body side. In an ink jet recording apparatus configured to store ink supplied from an ink supply source via an ink supply path in a sub tank and supply the stored ink to a recording head.
The sub-tank is provided with a stored ink stirring means that vibrates and stirs the ink stored inside.
The stored ink agitation means is composed of an elastic partition that partitions a part of the ink chamber of the sub tank and a vibration drive source attached to the elastic partition. The ink jet recording apparatus is characterized in that the above is stirred.
[0011]
According to a second aspect of the present invention, there is provided the ink jet recording apparatus according to the first aspect, wherein a vibration driving source is provided on the ink chamber bottom side of the elastic partition wall to vibrate the ink chamber bottom side. .
[0012]
According to a third aspect of the present invention, the elastic partition wall is formed of an elastic sheet, and the elastic sheet functions as a compliance portion that absorbs pressure fluctuation in the ink chamber. An ink jet recording apparatus.
[0013]
A fourth aspect of the present invention is the ink jet recording apparatus according to any one of the first to third aspects, wherein the vibration driving source is a plate-like piezoelectric vibrator.
[0014]
A fifth aspect of the present invention is the ink jet recording apparatus according to any one of the first to third aspects, wherein the vibration driving source is a vibration motor.
[0015]
6. The inkjet according to claim 1, wherein the ink is vibrated to the ink in the sub-tank by finely reciprocating the carriage in conjunction with the stored ink stirring means. Type recording device.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a plan view of an ink jet printer 1 (hereinafter simply referred to as printer 1), which is a typical ink jet recording apparatus to which the present invention is applied, and FIG. 2 is a perspective view of the carriage 2 as viewed obliquely from above. FIG. 3 is a front view of the sub tank 3, and FIG. 4 is a sectional view of the carriage 2.
[0017]
As shown in FIG. 1, the printer 1 is schematically composed of a carriage 2 on which a sub-tank 3 and a recording head 4 are mounted, and a printer main body 5. The printer main body 5 reciprocates the carriage 2 along the main scanning direction. A head scanning mechanism, a paper feeding mechanism for feeding the recording paper 6 in the paper feeding direction, a recovery mechanism for recovering the function of the recording head 4 that has been lowered by the thickened ink, and an ink tank 7 that stores ink to be supplied to the recording head 4 (A kind of ink supply source).
[0018]
First, the carriage 2 will be described.
As shown in FIG. 2, the carriage 2 is provided with a sub tank 3 on the upper surface side of a mounting base 10 formed in a substantially rectangular plate shape, and a recording head 4 on the lower surface side. A fixing boss 11 for attaching the sub-tank 3 projects from the upper surface of the mounting base 10, and an ink supply needle 12 and a needle filter 13 (FIG. 4) are attached in the vicinity of the fixing boss 11. The fixing boss 11, the ink supply needle 12, and the needle filter 13 are provided for each sub tank 3, and are arranged so that a plurality of sub tanks 3 are arranged in the main scanning direction. Further, as shown in FIG. 4, a flow path forming portion 14 projects downward from the lower surface of the mounting base 10, and the recording head 4 is joined to the front end surface of the flow path forming portion 14. Inside the flow path forming portion 14, an ink introduction path 15 is formed from the needle portion filter 13 to the ink introduction port 16 of the recording head 4.
[0019]
In this embodiment, since two types of ink are used, two sub tanks 3 are arranged in the main scanning direction. However, the present invention is also applicable to a configuration using three or more types of ink. Of course it applies. The sub-tank 3 is continuously used as it is even after the ink tank 7 is replaced.
[0020]
As shown in FIG. 3, the sub-tank 3 has an elliptical base portion 17 that is slightly longer in the lateral direction when viewed from the front, and an extension in which a lower end portion on one side of the base portion 17 is extended laterally (rightward in FIG. 3). And a portion 19, which is molded from a resin material such as polypropylene. A concave portion that becomes the ink chamber 20 is formed in the front portion of the base portion 17 so as to be recessed in the rear surface direction, and a cylindrical needle connection portion 21 is provided to project downward on the lower surface portion, and a plate shape is provided on the rear surface portion. The fastening portion 22 (FIG. 2) is formed.
[0021]
As shown in FIGS. 3 and 4, the ink chamber 20 has a shallow mortar shape, and is connected to the needle connecting portion 21 at a position slightly below the vertical center on the side surface. The upstream opening of the flow channel 23 faces. A tank section filter 24 is attached in the ink chamber 20 so as to cover the upstream opening. The upstream opening of the connection channel 23 may be opened on the bottom surface of the ink chamber 20.
[0022]
The needle connecting part 21 is a cylindrical part whose upper base end is closed and whose lower tip is open, and the downstream opening of the connection flow path 23 faces the ceiling surface of the internal space. The seal member 25 into which the ink supply needle 12 is liquid-tightly fitted is fitted in the internal space. The fastening portion 22 is a portion for attaching the sub tank 3 to the carriage 2, and the fastening screw 26 inserted into the fastening portion 22 is screwed to the fastening boss 11 to fasten the sub tank 3. An ink inlet 27 protrudes from the upper surface of the extending portion 19, and the bottom of the ink chamber 20 and the ink inlet 27 communicate with each other through a connection groove 29. An ink supply tube 30 that supplies ink stored in the ink tank 7 is connected to the ink inlet 27. Therefore, the ink that has passed through the ink supply tube 30 serving as an ink supply path flows into the sub tank 3 from the ink inlet 27.
[0023]
A transparent elastic sheet 31 is attached to the edge of the base 17 and the edge of the extension 19 so as to cover the front portions of the base 17 and the extension 19, and the opening of the ink chamber 20 and the connection groove 29 openings are sealed. As a result, a series of ink flow paths from the ink inlet 27 through the ink chamber 20 to the needle connection portion 21 is formed in the sub tank 3. The elastic sheet 31 becomes an elastic partition wall that partitions a part of the ink chamber 20 and can be deformed in a direction in which the ink chamber 20 is contracted and expanded. Due to this deformation, pressure fluctuations in the ink chamber 20 are absorbed by the damper action of the elastic sheet 31 functioning as a compliance portion. That is, the sub tank 3 functions as a pressure damper by the action of the elastic sheet 31. Therefore, the ink is supplied to the recording head 4 side in a state where the pressure fluctuation is absorbed in the sub tank 3.
[0024]
A piezoelectric vibrator 33 that functions as a vibration drive source (actuator) for the stored ink stirring means 32 is attached to the lower portion of the outer surface of the elastic sheet 31.
The piezoelectric vibrator 33 is a plate-like element in which rectangular piezoelectric thin films and thin film electrodes are alternately stacked. For example, a piezoelectric vibration mode piezoelectric element is used. The piezoelectric vibrator 33 is disposed on the bottom side of the ink chamber 20 in a state where the entire surface is bonded to the surface of the elastic sheet 31 constituting a part of the stored ink stirring means by an adhesive or the like. For this reason, when a potential difference is applied between the electrodes, the piezoelectric thin film is distorted, and the piezoelectric vibrator 33 is deformed to deform the elastic sheet 31. Therefore, when a potential difference is repeatedly applied between the electrodes, the piezoelectric vibrator 33 vibrates accordingly and the elastic sheet 31 is vibrated, and the ink in the ink chamber 20 can be vibrated.
[0025]
In the present embodiment, the single piezoelectric vibrator 33 is formed in a rectangular shape in accordance with the ink chamber 20 so that the bottom side of the ink chamber 20 can be preferentially vibrated. However, the present invention is not limited to this, and vibration is generated in the ink chamber 20. Any configuration can be used.
For example, the thin film electrode on the elastic sheet 31 side may be a common electrode, and the thin film electrode on the opposite side may be individually separated into a plurality of individual electrodes. In this case, when a potential difference is sequentially applied to each individual electrode, the whole can be deformed so as to wave. As a result, vibration can be applied to the ink inside so as to flow in the longitudinal direction of the ink chamber 20. A plurality of piezoelectric vibrators 33 may be arranged side by side on the surface of the elastic sheet 31.
[0026]
The shape and arrangement of the piezoelectric vibrator 33 are not limited to those described above, and the piezoelectric vibrator 33 may be arranged on the elastic sheet 31 in a state where the ink chamber 20 is vibrated. The period for vibrating the piezoelectric vibrator 33, that is, the vibration period for vibrating the ink may be high-frequency vibration or low-frequency vibration, or may be appropriately changed according to the viscosity of the pigment that colors the ink and the ink color. Is possible.
[0027]
Since the piezoelectric vibrator 33 is added to the elastic sheet 31 that partitions a part of the ink chamber 20 as described above, the elastic sheet 31 is vibrated by the deformation of the piezoelectric vibrator 33 and the ink in the ink chamber 20 is transferred to the ink. Can give vibration. Therefore, the ink in which the pigment component has settled in the subtank 3 can be stirred to disperse the pigment component, and the pigment component can be diffused. As a result, the increase in particle size due to the uneven density and aggregation of the pigment component caused by the sedimentation of the pigment component is eliminated, the image recorded on the recording paper 6 has a constant color, and the filter 24 is clogged. Can be prevented.
[0028]
In the present embodiment, since the piezoelectric vibrator 33 is disposed on the bottom side of the ink chamber 20, it is possible to concentrate vibrations on the pigment component that has settled on the bottom side of the ink chamber 20, and to efficiently remove the pigment component. Can be dispersed. Further, since the piezoelectric vibrator 33 is disposed so as to face the filter 24 (see FIG. 4), the ink can flow to the filter 24 side by vibration to release the pigment component attached to the surface of the filter 24. it can.
[0029]
In addition, since the piezoelectric vibrator 33 that vibrates the ink is disposed in the sub tank 3 mounted on the carriage 2, the ink can be stirred even while the carriage 2 is in operation. For example, the ink can be agitated by finely reciprocating the carriage 2 in the main scanning direction in conjunction with the vibration of the ink caused by the action of the piezoelectric vibrator 33.
The stirring by the movement of the carriage 2 may be performed simultaneously with the vibration by the piezoelectric vibrator 33 or before and after the vibration.
[0030]
As illustrated in FIG. 4, the recording head 4 includes a box-shaped case 34, a comb-like piezoelectric vibrator 35 housed in a housing space of the case 34, and a lower surface (tip surface) of the case 34. The joined flow path unit 36, the ink supply pipe 37 that supplies ink to the flow path unit 36, and the nozzle array in which a plurality of nozzle openings are arranged along the sub-scanning direction are separated in the main scanning direction to be parallel to two lines. The nozzle plate 39 is formed.
The recording head 4 expands and contracts a pressure chamber (not shown) of the flow path unit 36 by the piezoelectric vibrator 35 and ejects ink supplied to the pressure chamber from the nozzle openings of the nozzle plate 39 as ink droplets. Let
[0031]
Next, the configuration on the printer body 5 side will be described.
The head scanning mechanism includes a guide member 40 extending in the left-right direction, a pulse motor 41, a drive pulley 42 connected to the rotation shaft of the pulse motor 41 and driven to rotate by the pulse motor 41, and an idle pulley 43. And a timing belt 44 that is stretched between the drive pulley 42 and the idle pulley 43 and connected to the carriage 2, and a printer controller (not shown) that controls the rotation of the pulse motor 41. . Therefore, when the pulse motor 41 is operated, ink droplets can be ejected from the nozzle openings of the recording head 4 while moving the carriage 2 and recording can be performed on the recording paper 6, and when the forward / reverse rotation of the pulse motor 41 is repeated in a short cycle, As described above, the ink in the sub tank 3 can be stirred by finely shaking the carriage 2.
[0032]
The paper feed mechanism includes a paper feed roller (not shown) that is rotationally driven by a paper feed motor and a printer controller, and sequentially feeds recording paper 6 (not shown) in conjunction with a recording operation.
[0033]
Next, the stirring control of the ink stored in the sub tank 3 will be described.
The piezoelectric vibrator 33 disposed in the sub tank 3 is controlled by a printer controller. The printer controller controls the recording head 4 and the carriage 2 based on print data from the host computer to print characters and images on the recording paper 6, and includes a ROM storing control data and the like. A control unit including a RAM as a work area, a CPU, a non-volatile memory (for example, EEPROM) that stores and holds various data, a clock circuit, and the like are disposed in the printer main body 5.
[0034]
The printer controller acquires date / time data of printing end or power-off from the clock circuit or the host computer and stores it in the nonvolatile memory. Then, the date / time data is read from the non-volatile memory when the power is turned on, and the date / time data of the day is acquired from the clock circuit or the host computer to calculate the period during which the printer 1 has not been used. If this calculation period exceeds a set period (for example, 2 months), the piezoelectric vibrator 33 is vibrated to stir the ink in the sub tank 3. Therefore, even if the pigment component is settled by not using it for a long time, the pigment component returns to the original diffusion state by the stirring action, and as a result, the image quality can always be kept constant.
[0035]
The setting period can be changed as appropriate, and ink agitation may be executed every time the power is turned on or every time printing is started.
[0036]
In the above embodiment, the piezoelectric vibrator 33 is used as the vibration drive source of the stored ink agitation means 32. However, the vibration drive source in the present invention is not limited to this, and the ink in the sub tank 3 is vibrated. Any configuration is possible if possible. For example, a small vibration motor may be provided in the sub tank 3 to stir the ink. In this case, if the vibration motor is attached to a part other than the elastic sheet 31, for example, the base 17 of the sub tank 3, the compliance value of the elastic sheet 31 is not lowered.
[0037]
【The invention's effect】
As described above, the present invention has the following effects.
That is, since the storage ink stirring means for stirring the ink in the sub tank is provided, even if the pigment in the ink settles in the sub tank due to being left for a long period of time, the settled pigment is put into the ink solvent. The ink can be dispersed and the ink can be returned to a normal state. As a result, the density unevenness of the image caused by the sedimentation of the pigment can be prevented, and the recorded image can be stabilized. Further, since the aggregated pigment can be dispersed in the ink solvent in a reduced state, clogging by the pigment can be prevented, and ink supply to the recording head can be stabilized.
[0038]
Further, when the stored ink agitation means is constituted by an elastic partition wall that partitions a part of the ink chamber of the sub tank and a vibration drive source attached to the elastic partition wall, the elastic partition wall is vibrated by the vibration drive source, and the ink in the sub tank is Stirring can be ensured. If a vibration drive source is disposed on the ink chamber bottom side of the elastic partition wall, the bottom portion that is likely to settle can be vibrated with priority, so that stirring can be performed efficiently.
[0039]
Further, when the vibration drive source is provided on the elastic sheet functioning as the compliance section, the stored ink agitation means can have a simple configuration.
[0040]
If the vibration drive source is a plate-like piezoelectric vibrator, stirring can be performed efficiently with a small current, and powerful stirring can be easily performed using a vibration motor.
[0041]
Further, when the carriage is vibrated finely, the entire sub tank can be vibrated, so that the agitation can be performed more reliably.
[Brief description of the drawings]
FIG. 1 is a plan view of an ink jet printer according to the present invention.
FIG. 2 is a perspective view of a carriage.
FIG. 3 is a front view of a sub tank.
FIG. 4 is a cross-sectional view of a carriage.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Inkjet printer 2 Carriage 3 Sub tank 4 Recording head 5 Printer main body 6 Recording paper 7 Ink tank 10 Mounting base 11 Fixing boss 12 Ink supply needle 13 Needle part filter 14 Flow path formation part 15 Ink introduction path 16 Ink introduction port 17 Base DESCRIPTION OF SYMBOLS 19 Extension part 20 Ink chamber 21 Needle connection part 22 Fastening part 23 Connection flow path 24 Tank part filter 25 Seal member 26 Fastening screw 27 Ink inlet 29 Connection groove part 30 Ink supply tube 31 Elastic sheet 32 Stored ink stirring means 33 Piezoelectric vibrator 34 as a vibration drive source Case 35 Piezoelectric vibrator 36 for ink ejection Flow path unit 37 Ink supply pipe 39 Nozzle plate 40 Guide member 41 Pulse motor 42 Drive pulley 43 Free pulley 44 Timing belt

Claims (6)

A recording head and a sub tank are mounted on a carriage that reciprocates in the main scanning direction, and ink supplied via an ink supply path from an ink supply source disposed on the apparatus main body side is stored in the sub tank. In an ink jet recording apparatus configured to supply to a recording head,
The sub-tank is provided with a stored ink stirring means that vibrates and stirs the ink stored inside.
The stored ink agitation means is composed of an elastic partition that partitions a part of the ink chamber of the sub tank and a vibration drive source attached to the elastic partition. An ink jet recording apparatus.   2. The ink jet recording apparatus according to claim 1, wherein a vibration drive source is disposed on the ink chamber bottom side of the elastic partition wall to vibrate the ink chamber bottom side.   The ink jet recording apparatus according to claim 1, wherein the elastic partition wall is formed of an elastic sheet, and the elastic sheet functions as a compliance unit that absorbs pressure fluctuation in the ink chamber.   4. The ink jet recording apparatus according to claim 1, wherein the vibration driving source is a plate-like piezoelectric vibrator.   4. The ink jet recording apparatus according to claim 1, wherein the vibration driving source is a vibration motor.   6. An ink jet recording apparatus according to claim 1, wherein the ink is vibrated finely by reciprocating the carriage in conjunction with the stored ink agitation means.

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