JP4337330B2 - Inkjet recording device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an ink jet recording apparatus that supplies ink to a recording head that ejects ink droplets by exchanging cartridges.
[0002]
[Prior art]
Inkjet recording devices are relatively low in cost and can easily obtain printing quality close to photographic quality. However, in the case of pigment ink in which pigment particles are turbid, the pigment particles precipitate over time. The density changes greatly before and after replacing the ink cartridge.
[0003]
In order to solve such a problem, as shown in, for example, Japanese Patent Application Laid-Open No. 11-48491, a large ink tank is provided, and when the ink is reduced to a certain extent, new ink is replenished and an ink pigment is supplied. It is also conceivable to reduce the density difference.
[0004]
[Problems to be solved by the invention]
According to this, although a sudden change in density can be alleviated to some extent, there is a disadvantage that it takes time to transfer the ink of the ink cartridge to the tank.
The present invention has been made in view of such problems, and an object of the present invention is to make it unnecessary to transfer ink from an ink cartridge to a tank, and to perform a rapid change in color tone and density before and after ink cartridge replacement. An object of the present invention is to provide an ink jet recording apparatus that can be relaxed.
[0005]
Another object of the present invention is to provide an ink jet recording apparatus that can effectively use ink whose amount of ink is reduced and whose density is extremely increased.
[0006]
[Means for Solving the Problems]
The invention according to claim 1 in order to solve such a problem, in the ink jet recording device for supplying ink in the ink cartridge via the buffer tank to the ink jet recording head for ejecting ink droplets, the buffer tank, the ink remaining amount The ink supply control means for controlling the replenishment of ink from the ink cartridge to the buffer tank has a capacity capable of storing all of the ink of the ink cartridge that has become a specified value, and detects the ink level of the buffer tank Based on the output signal of the sensor, the first time from the buffer tank until the predetermined amount of ink corresponding to the capacity of the buffer tank is supplied from the ink cartridge to the buffer tank immediately after the ink cartridge is replaced . a predetermined amount of ink is consumed the Baffata Each time the ink surface of the click is reduced from a first level to a second level, the ink supply to the buffer tank to the first level, the ink of a predetermined amount of approximately capacity of the buffer tank from said ink cartridge A second predetermined amount of ink larger than the first predetermined amount is consumed from the buffer tank until the remaining amount of ink in the buffer cartridge is replenished to the specified value or less, and the ink in the buffer tank is consumed. Whenever the liquid level drops from the first level to the third level, the buffer tank is refilled with ink up to the first level, and when the remaining amount of ink in the ink cartridge falls below the specified value, the buffer A third predetermined amount of ink that is greater than the second predetermined amount and greater than or equal to the predetermined value is consumed from the tank, and the buffer When the ink surface of the click is lowered from the first level to the fourth level, wherein the transferring all of the ink remaining in the ink cartridge to the buffer tank.
According to this invention, since the ink of the ink cartridge that was previously installed remains in the buffer tank, even if there is a large change in the ink concentration of the ink cartridge, the previous ink remaining in the buffer is The ink of this ink cartridge is mixed and the density can be gradually changed to that of the current ink cartridge, and a sudden change in color tone and density before and after replacement of the ink cartridge can be mitigated. In addition, the ink density of a new ink cartridge can be handled in a short time.
[0007]
BEST MODE FOR CARRYING OUT THE INVENTION
Therefore, details of the present invention will be described below based on the illustrated embodiment.
FIG. 1 shows an embodiment of the present invention. An ink jet recording head unit is provided on a carriage 1 that is guided in a reciprocating direction in the paper width direction. A cover 3 is opened and closed on one side of a housing 2. A possible ink cartridge housing 4 is provided, and an operation panel 5 is provided on the other side.
[0008]
FIG. 2 shows an embodiment of the present invention, in which a recording head 6 for ejecting black ink provided on the carriage 1 and a recording head 7 for ejecting color inks such as yellow, cyan, and magenta are shown. Are connected to buffer tanks 12, 13, 14, 15 via ink supply tubes 8, 9, 10, 11 respectively. Each buffer tank 12, 13, 14, 15 is connected to a cartridge containing black, yellow, cyan, and magenta ink via tubes 16, 17, 18, and 19.
[0009]
For example, as shown in FIG. 3, the ink cartridges 20, 21, 22, and 23 operate the ink end detector in the ink near end state and the ink end state with the flexible ink bag 30 in which the deaerated ink is sealed. The ink end detection plate 31 and the plug body 32 provided in the ink bag 30 are accommodated in a hard case composed of a case body 33 and a lid body 34 so as to be exposed.
With such a configuration, when an ink cartridge is loaded into the ink cartridge housing portion 4, the ink cartridges 20, 21, 22, 23 are connected to the tubes 16, 17, 18, via the ink supply needles (not shown) disposed in the housing portion 4. 19 is connected.
[0010]
By the way, since the buffer tanks 12, 13, 14, and 15 are filled with ink by applying a negative pressure to the recording head, even if the ink is forcibly discharged from the recording head, a sudden ink discharge occurs. It is selected to be able to store the ink of the previous cartridge with a capacity that can alleviate the density change to some extent.
[0011]
In this embodiment, when printing proceeds and a specific ink cartridge, for example, a magenta ink cartridge, is consumed, the ink is replaced with a new magenta ink cartridge. When the replacement of the ink cartridge is completed, the recording head 7m that discharges at least magenta ink is sealed by the capping unit 25 and the ink is forcibly discharged from the nozzle opening. As a result, bubbles that have entered the flow path such as a tube by the replacement of the ink cartridge are discharged.
[0012]
When the recording operation is resumed in this state, ink droplets are ejected from the recording head 7, ink in the buffer tanks 12, 13, 14, 15 is supplied to the recording head 7, and the ink cartridges 20, 21, 22, 23 are buffered. New ink is supplied to the tanks 12, 13, 14, and 15.
[0013]
In this case, if the magenta ink cartridge is replaced, the ink of the magenta ink cartridge that was previously installed remains in the buffer tank 15, so even if there is a large change in the ink density of the ink cartridge. Since the ink of the current ink cartridge is mixed with the previous ink remaining in the buffer and the density gradually changes to that of the current ink cartridge, a sudden color change can be prevented.
[0014]
FIG. 4 shows a second embodiment of the present invention by taking the above-mentioned magenta ink supply system as an example. In this embodiment, an ink cartridge 23 and a buffer tank 15 are provided with an ink between them. A transfer pump 40 is connected, and a liquid level sensor 41 is provided in the buffer tank 15.
[0015]
The pump control means 43 drives the motor 42 so as to transfer the ink in the ink cartridge 23 to the buffer tank 15 based on detection signals from the ink end detection plate 31 of the ink cartridge 23 and the liquid level sensor 41.
[0016]
In this embodiment, when the ink amount in the buffer tank 15 becomes less than the specified value, the pump control means 43 rotates the motor 42 to transfer the ink in the ink cartridge 23 to the buffer tank 15, and the ink amount in the buffer tank 15 is reduced. When the specified value is reached, the motor 42 is stopped.
[0017]
Thereafter, when such an operation is repeated and the ink amount of the ink cartridge reaches the near end, the pump control unit 43 suspends the driving of the motor 42 until the ink level of the buffer tank 15 decreases to near the near end.
[0018]
In this way, when the ink in the buffer tank 15 becomes a minimum amount, the motor 42 is driven to transfer all the ink remaining in the ink cartridge 23 to the buffer tank 15 and wait for replacement of the ink cartridge. As a result, particularly in an ink cartridge containing pigment ink, the pigment precipitated in the lower part is transferred to the buffer tank 15.
[0019]
When a new magenta ink cartridge is installed, the pump control means 43 drives the motor 42 to transfer a new amount of ink from the new ink cartridge to the buffer tank 15. Thereby, the ink containing the pigment at a high concentration and the new ink are mixed.
[0020]
Next, at least the nozzle opening for ejecting magenta ink is sealed by the capping means 25, and the ink is forcibly discharged from the nozzle opening to remove bubbles that have entered the flow path such as a tube by replacing the ink cartridge. .
[0021]
According to this embodiment, the ink remaining amount is reduced, and the ink whose density is extremely increased can be effectively used for printing without being wasted and without causing a sudden change in color density.
[0022]
FIG. 5 shows an embodiment of the ink jet recording apparatus according to the present invention. The carriage 40 is guided by a scanning guide member 43 through a timing belt 42 driven by a carriage motor 41 and the paper feeding member 44 is moved. It is configured to reciprocate in the longitudinal direction, that is, the main scanning direction which is the width direction of the recording paper.
An ink jet recording head (not shown) capable of ejecting each ink as droplets is provided on the surface of the carriage 40 facing the paper feed member 44, in this embodiment, the lower surface. On the carriage 40, sub tanks 45B, 45C, 45M and 45Y for supplying ink to the recording head are mounted.
[0023]
A cartridge holder 46 is arranged on one side of the frame so that the ink cartridges 47B, 47C, 47M, 47Y are detachably attached. The ink cartridges 47B, 47C, 47M, 47Y are attached and detached by attaching / detaching sensors 48B, 48C, 48M, It is configured to be detected by 48Y. Each ink cartridge 47B, 47C, 47M, 47Y is connected to the buffer tanks 50B, 50C, 50M, 50Y via tubes 49B, 49C, 49M, 49Y.
[0024]
Each of the buffer tanks 50B, 50C, 50M, and 50Y has a capacity that can reduce the density change when the ink cartridges 47B, 47C, 47M, and 47Y are replaced, and has at least four levels inside as shown in FIG. Liquid level sensors 51, 52, 53, and 54 are arranged so that the liquid level can be detected. The buffer tanks 50B, 50C, 50M, and 50Y are arranged at a slightly high position so that ink can be supplied to the sub tanks 45B, 45C, 45M, and 45Y by the flow of gravity, and the sub tanks 45B are passed through the tubes 60B, 60C, 60M, and 60Y. , 45C, 45M, 45Y to supply ink to the recording head.
[0025]
Each of the ink cartridges 47B, 47C, 47M, and 47Y is configured by housing the ink pack 73 in a hard case made up of a case main body 71 having a pressurized air inlet 70 and a lid 72 as shown in FIG. Has been. The ink pack 73 is stored in an airtight manner with the ink supply port 74 protruding from the window 75 of the case body 71. The pressurized air inlets 70 of the respective ink cartridges 47B, 47C, 47M, 47Y are connected to independent air pumps 75B, 75C, 75M, 75Y by tube tubes 74B, 74C, 74M, 74Y, respectively. The ink is discharged to the buffer tanks 50B, 50C, 50M, and 50Y by the applied pressure.
[0026]
FIG. 8 shows an embodiment of the ink supply control apparatus for one type of ink supply path. When ink is consumed by the recording head by printing or the like, the sub tanks 45B, 45C, 45M, 45Y ( Ink flows into the recording head from this, and the ink in the buffer tanks 50B, 50C, 50M and 50Y (represented by these as 50) is sub tank 45. The liquid level of the buffer tank 50 is lowered.
[0027]
When the liquid level of the buffer tank 50 is lowered to the third level L3 in this way (step A), a signal is output from the liquid level sensor 53, and the ink supply control means 80 is operated by the air pumps 75B, 75C, 75M, 75Y (these (Represented by reference numeral 75 as a representative) is driven (step B), and the liquid level is supplied to the buffer tank 50 to the first level L1.
When the sensor 51 detects that the ink has been replenished to the first level L1 (Step C), the ink supply control means 80 stops the air pump 75 to stop the ink replenishment (Step D). Thereafter, each time the liquid level in the buffer tank 50 is lowered to the third level L3 and a signal is output from the sensor 53, the process from step (a) to step (d) is repeated to set the ink amount in the buffer tank 50 to the first level. The range ΔL2 between the first level L1 and the third level L3 is maintained.
[0028]
When the near end detecting means 81 detects that the ink amount of the ink cartridge 47 has decreased to near the end in this way (step e), the ink supply control means 80 does not replenish ink at the third level L3. Then, it is lowered to the fourth level L4 and waits for a signal to be output from the sensor 54. The range ΔL3 between the first level L1 and the fourth level L4 is set to an amount that can accommodate all the ink of the ink cartridge 47 that has become near-end.
[0029]
When the ink level in the buffer tank 50 is lowered to the fourth level L4 and a signal is output from the sensor 54 (Step F), the ink supply control means 80 operates the air pump 75 for a predetermined time (Step F). When the time required to discharge all the ink remaining in the ink cartridge 47 has passed (Step H), when the ink in the ink cartridge 47 moves to the buffer tank 50, a cartridge replacement signal is output and an alarm is issued. Then, the ink cartridge 47 is urged to be replaced (step).
[0030]
When the user replaces the ink cartridge 47 based on this alarm (Step No.), a signal is output from the attachment / detachment sensors 48B, 48C, 48M, and 48Y (represented by reference numeral 48). In this state, when the ink in the buffer tank 50 is consumed and the ink is slightly reduced, that is, when the ink is reduced to the second level L2 and a signal is output from the sensor 52 (step), the ink supply control means 80 drives the air pump 75. Then, ink is supplied up to the first level L1 (step A, W, F). Thereafter, when the liquid level in the buffer tank 50 is lowered to the second level L2, the air pump 75 is operated to supply new ink to the buffer tank 50 each time a smaller amount of ink is consumed in the range ΔL1, that is, in the normal state. The ink in the cartridge 47 is replenished sequentially. As a result, the ink of the previous ink cartridge 47 is newly installed in a short time and the ink in the ink cartridge 47 is mixed to smoothly prevent the density fluctuation in a short time.
[0031]
In this way, when the ink corresponding to the capacity of the buffer tank 50 is replenished from the new ink cartridge (step YO), the operation returns to the normal operation, that is, step IB, and the ink amount in the buffer tank 50 is changed to the third amount. Ink is replenished from the ink cartridge 47 at the time when the level drops to the level. Thereby, it is not necessary to drive the air pump 75 frequently, and noise can be prevented.
[0032]
In the above embodiment, when the ink in the ink cartridge becomes near-end, the buffer tank 50 waits for the ink in the buffer tank to be consumed to the lowest level L3. Even when all the ink in the ink cartridge 47 is transferred to the buffer tank 50 when the remaining amount of ink in the ink cartridge becomes greater, the same effect is obtained.
In the above-described embodiments, the sub tank and the buffer tank are provided independently. However, it is obvious that the same effect can be obtained even if the capacity of the sub tank is increased to perform the function of the buffer tank. is there.
Furthermore, in the above-described embodiments, the color change caused by the precipitation of the pigment has been described. However, it is obvious that the inconvenience caused by a slight density difference between lots can be eliminated in the same manner.
[Brief description of the drawings]
FIG. 1 is an external view showing an embodiment of an ink jet recording apparatus of the present invention.
FIG. 2 is a configuration diagram showing an embodiment of an ink supply system of the inkjet recording apparatus.
FIG. 3 is an assembled perspective view showing an embodiment of the ink cartridge.
FIG. 4 is a configuration diagram showing another embodiment of the ink supply system of the inkjet recording apparatus.
FIG. 5 is a configuration diagram showing a second embodiment of the ink jet recording apparatus of the present invention.
FIG. 6 is a cross-sectional view showing an embodiment of a buffer tank of the recording apparatus.
FIG. 7 is an assembled perspective view showing an embodiment of an ink cartridge used in the recording apparatus.
FIG. 8 is a block diagram illustrating an embodiment of an ink supply control device.
FIG. 9 is a flowchart showing the operation of the ink supply control apparatus.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Carriage 6, 7 Recording head 12-15 Buffer tank 20-23 Ink cartridge 40 Ink transfer pump 41 Liquid level sensor

Claims (1)

In an inkjet recording apparatus that supplies ink from an ink cartridge to a inkjet recording head that ejects ink droplets via a buffer tank,
The buffer tank has a capacity capable of storing all the ink of the ink cartridge in which the remaining amount of ink becomes a specified value,
Ink supply control means for controlling replenishment of ink from the ink cartridge to the buffer tank is based on an output signal of a sensor for detecting the ink level of the buffer tank,
Said immediately after the ink cartridge is replaced to a predetermined amount of ink of about capacity of the buffer tank is supplied into the buffer tank from said ink cartridge, said from the buffer tank is consumed ink of the first predetermined amount Each time the ink level in the buffer tank drops from the first level to the second level, the buffer tank is refilled with ink to the first level ,
Until a predetermined amount of ink corresponding to the capacity of the buffer tank is supplied from the ink cartridge to the buffer tank and the remaining amount of ink in the ink cartridge becomes equal to or less than the specified value, the first predetermined amount from the buffer tank. Each time the second predetermined amount of ink is consumed and the ink level in the buffer tank drops from the first level to the third level , the ink is supplied to the buffer tank to the first level ;
When the remaining amount of ink in the ink cartridge becomes equal to or less than the specified value, a third predetermined amount of ink that is greater than the second predetermined amount and greater than or equal to the specified value is consumed from the buffer tank. An ink jet recording apparatus , wherein when the liquid level is lowered from the first level to the fourth level, all ink remaining in the ink cartridge is transferred to the buffer tank .

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