JPH10100445A - Ink jet recorder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ink jet recorder in which an ink tank can be replaced effectively without replacing the electrode, only a pair of electrodes is required for a plurality of ink tanks and residual quantity of ink can be detected while mounting the ink tank for a conventional ink jet recorder as it is. SOLUTION: A pair of mutually insulated electrodes 72, 73 are disposed closely to a platen roller in the vicinity of a purge cap so that each ink tank 71 passes between the electrodes before and after a movement of carriage to a position where recovery operation of an ink jet head is performed. Residual quantity of ink can be detected for each ink tank 71 by detecting the capacitance between electrodes 72, 73 through a residual quantity of ink detection circuit in synchronism with the timing for locating each ink tank 71 between both electrodes through movement of the carriage.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink jet recording apparatus, and more particularly, to an ink jet recording apparatus capable of detecting the remaining amount of ink in an ink tank.

[0002]

2. Description of the Related Art In an ink jet recording apparatus, recording is performed by ejecting ink held in an ink tank onto recording paper or the like. If the ink tank runs out of ink, recording cannot be performed. For this reason, it is necessary to replace the ink tank with the reduced amount of ink with a new ink tank and replenish the ink. However, depending on the material of the ink tank and the structure of the mounting part of the carriage, the remaining amount of ink may not be visually recognized from the outside, and in such a case, it will be noticed that there is no ink only after recording becomes impossible due to lack of ink. Inconvenient.

For this purpose, an ink jet recording apparatus is provided with a means for detecting the remaining amount of ink. As one of the methods for detecting the remaining amount of ink for this purpose, the fact that the capacitance of the ink tank differs depending on the remaining amount of ink can be used. Therefore, in a conventional ink jet recording apparatus, two electrode plates insulated from each other are provided in an ink tank, and the remaining amount of ink is known by detecting a capacitance between the electrode plates by a detection circuit provided on the apparatus side. It was like.

[0004]

However, in the conventional ink jet recording apparatus, since two electrode plates are provided on the ink tank side, the electrode plate must be replaced every time the ink tank is replaced. It is wasteful. Further, when a plurality of ink tanks are mounted as in a color ink jet recording apparatus, an electrode plate must be provided for each ink tank, which is also a factor of cost increase. Furthermore, even if a detection circuit is provided on the apparatus side, if a conventional ink tank without an electrode plate is mounted, the remaining amount cannot be detected, so that it can be said that compatibility is lacking.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems of the conventional ink jet recording apparatus, and can replace an ink tank without wasting without replacing electrodes, and can be applied to a plurality of ink tanks. It is an object of the present invention to provide an ink jet recording apparatus which requires only a pair of electrodes and can detect the remaining amount of ink by directly mounting an ink tank for a conventional ink jet recording apparatus.

[0006]

According to a first aspect of the present invention, there is provided a recording medium having a carriage movable in a recording direction and a plurality of ink tanks mounted on the carriage. An ink jet recording apparatus which performs recording by discharging ink in an ink tank onto a recording medium, wherein the carriage moves to a predetermined position within a range where each of the ink tanks can be located, in parallel with a recording direction and A pair of electrodes provided to face each other with the ink tank interposed therebetween, and a capacitance measuring unit for measuring a capacitance between the pair of electrodes; It is specified by detecting the remaining amount of ink.

In this ink jet recording apparatus, when one of the plurality of ink tanks is at a predetermined position due to movement of the carriage, a pair of electrodes are opposed to each other with the ink tank interposed therebetween. The capacitance between the pair of electrodes at this position depends on the remaining amount of ink in the ink tank. That is, since ink generally has a much higher dielectric constant than air, the capacitance is largest when the ink tank is full of ink, and the capacitance decreases as the ink is consumed and decreased by performing printing. Become smaller. Then, since this capacitance is measured by the capacitance measuring means, the remaining amount of ink in the ink tank is detected. Therefore, the remaining amount of ink can be detected for each of the plurality of ink tanks by the movement of the carriage by the capacity measuring means and the pair of electrodes.

Therefore, according to this ink jet recording apparatus, by monitoring the capacitance, the user can know the ink tank nearing the end of the ink, and can replace the ink tank before the recording becomes impossible due to the ink shortage. Be prompted. Further, since the ink tank itself is not provided with an electrode, even if the ink tank is replaced, the pair of electrodes is used as it is, and there is no waste. In addition, an ink tank for a conventional type ink jet recording apparatus which does not detect the remaining amount of ink can be used as it is, as long as it is mounted on a carriage, and the remaining amount of ink can be detected.

According to a second aspect of the present invention, there is provided the ink jet recording apparatus according to the first aspect, wherein each of the ink tanks reaches the predetermined position in synchronization with the movement of the carriage. In this case, the capacitance is measured at each timing located between the pair of electrodes, and the remaining amount of ink is detected for each ink tank.

In this ink jet recording apparatus, the capacitance measurement by the capacitance measuring means is performed in synchronization with the movement of the carriage. Specifically, when there is an ink tank that reaches a predetermined position by the movement of the carriage, the capacitance is measured at a timing when the ink tank is located between the pair of electrodes. Therefore, about the ink tank,
The remaining amount of ink is detected by measuring the capacitance. Then, since the capacitance is measured by the capacitance measuring means at the same timing for each ink tank, the remaining ink amount is detected for each ink tank.

According to a third aspect of the present invention, there is provided the ink jet recording apparatus according to the first or second aspect,
The width of the electrode is specified to be less than or equal to a minimum width on a surface of the ink tank facing the electrode.

In this ink jet recording apparatus, when one of the ink tanks is positioned between the pair of electrodes by the movement of the carriage and the capacitance is measured by the capacitance measuring means, the size in the width direction (the carriage moving direction) is Each electrode is within the width of the surface of the ink tank facing the electrode. For this reason, the capacitance is measured without being affected by the adjacent ink tank, so that the accuracy of detecting the remaining amount of ink is high.

According to a fourth aspect of the present invention, in the ink jet recording apparatus according to any one of the first to third aspects, the pair of electrodes are insulated from each of the ink tanks. Specified as

In this ink jet recording apparatus, since the pair of electrodes and each ink tank are insulated, the capacitance of the ink tank located therebetween can be measured by the pair of electrodes, and the amount of remaining ink can be detected. Is possible.
Here, the insulation between the pair of electrodes and each ink tank may be achieved by forming the outer shape of the ink tank with an insulator, or by covering the surfaces of the pair of electrodes facing the ink tank with the insulator. Alternatively, a certain gap may be secured between the pair of electrodes and the ink tank.

[0015]

Embodiments of the present invention will be described below in detail with reference to the drawings. The ink jet recording apparatus 10 according to the present embodiment uses a piezoelectric element type ink jet head, and its main part has a schematic configuration shown in FIG.

In the schematic perspective view of FIG. 1, a cylindrical platen roller 81 for conveying a recording sheet S is disposed on a frame 80 of the ink jet recording apparatus 10 so as to be rotatable around an axis. Then, the platen roller 81
A guide rod 82 and a guide rail 83 are provided in parallel with the carriage, and the carriage 84 can be moved in parallel with the platen roller 81 while being supported by these. The carriage 84 is driven via a belt 86 by a CR motor 85 provided below the frame 80. The carriage 84 is mounted with ink jet heads 70 of four colors (black Bk, cyan Cy, magenta M, and yellow Y) that perform full-color printing by discharging ink from nozzles.

Further, on the carriage 84, ink tanks 71 for supplying ink to the ink jet head 70 are mounted in parallel for four colors so as to be detachable. Each ink tank 71 is a normal one made of an insulating resin. Further, the frame 80 includes a wiper 87 for wiping the nozzle surface and a purge for sucking the deteriorated ink covering the nozzle surface as a recovery system for recovering the ink discharge state of the inkjet head 70 when the ink discharge state deteriorates. A cap 88 is provided. Further, an LF motor 89 for driving a platen roller 81 and a recovery system is mounted. Further, the purge cap 8 in the frame 80
A pair of electrodes 7 for detecting the remaining amount of ink in the ink tank 71 is provided at a position near the platen roller 81 near the position 8.
Reference numerals 2 and 73 are provided so as to face up and down with respect to the movement path of the ink tank 71 by the carriage 84.

The pair of electrodes 72 and 73 are fixed to the frame 80, and one of the four ink tanks 71 is moved between them by moving the carriage 84 as shown in FIGS. It is arranged so that it can be located. That is, the ink tank 71 of black in FIG. 2, cyan in FIG. 3, magenta in FIG. 4, and yellow in FIG. 5 is located at a position sandwiched between the electrodes 72 and 73. FIG. 6 shows a state where none of the ink tanks 71 is located between the electrodes 72 and 73. Such a state exists during execution of print recording.

Then, as shown by symbols E and T in FIG.
The width E of the electrode 72 (also the width of the electrode 73) is equal to or less than the width T of the ink tank 71. 2 to 6, each ink tank 71 has the same width. However, if the width of the ink tank 71 differs depending on the color (only black is wider than others), The width E of the electrode 72 is set to be equal to or smaller than the smallest one of the widths T of the ink tank 71. The electrode 7
The surfaces of the surfaces 2 and 73 facing the ink tank 71 are parallel to the moving direction of the carriage 84. Further, the electrodes 72 and 73 are insulated from each other so that this insulation is maintained even when any of the ink tanks 71 is between them.

Next, a control system of the ink jet recording apparatus 10 will be described. As shown in FIG. 7, the control system mainly includes a head driver 30, a gate array 31, and a CPU 32. 7, the head driver 30
And an ink jet head 70 are mounted on a carriage 84, and the others (except for the host 78) are installed in the apparatus main body. The head driver 30 is a circuit that applies a drive signal to each channel of the inkjet head 70. The gate array 31 is a circuit that receives print data (code data) from a host (a personal computer or the like) 78 via the interface 33, develops the print data into image data, transfers the print data to the head driver 30, and the like. Further, the gate array 31 is provided with an image memory 34 for storing developed image data.

The CPU 32 controls the ink jet recording apparatus 1
0 is a one-chip microcomputer that performs overall control of the entire operation. The CPU 32 and the gate array 31 are connected by a bus 35, and can exchange data, timing signals, and the like. ROM 36 and RAM 37
Is also connected. Further, the CPU 32 is also connected to an ink remaining amount detection circuit 40. The remaining ink detection circuit 40 is a circuit that detects the remaining amount of ink in the ink tank 71 via the pair of electrodes 72 and 73. Further, C
The PU 32 is also connected to a switch panel 38 for setting and displaying print parameters and the like and a drive system 39 of a mechanical part. Here, the drive system 39 includes a CR motor 85, an LF motor 89, a position sensor therefor, and the like.

The ink remaining amount detecting circuit 40 will be described with reference to FIG. The ink remaining amount detection circuit 40 has a logic IC 45 having a hysteresis function, and a timing resistor 43 (R) connected in parallel to the logic IC 45. A protection resistor 44 (Rs) is provided on the input side of the logic IC 45, and is connected to the electrode 72 via the branch point A. The output side of the logic IC 45 is connected to the CPU 32 via a branch point B. The electrode 73 is grounded. The electrode 72 and the electrode 73 are insulated from each other even when the ink tank 71 is located therebetween, so that a capacitor (C) is formed. Depends on Ink has a much higher dielectric constant than air. A known CR oscillation circuit is constituted by the logic IC 45, the timing resistor 43, and the capacitor C, and the CPU 3 outputs a pulse having a frequency corresponding to the capacitance of the capacitor C to the CPU 3.
2 to detect the remaining amount of ink.

Next, the operation of the ink jet recording apparatus 10 will be described. The basic operation of the inkjet recording apparatus 10 is to perform print recording on the recording paper S. In other words, the platen roller 81 is driven by the LF motor 89 to convey the line on which the recording sheet S is recorded to the position facing the ink-jet head 70, and the carriage 84 is driven by the CR motor 85 while the ink tank 71 is driven in accordance with the print data. Ink is ejected from the inkjet head 70 onto the recording paper S to perform print recording. Here, when the print data is multi-color data, the four colors of ink in the ink tanks 71 are selectively used according to the data, and color print recording is performed. In addition, since the ejection state of the ink jet head 70 is poor due to the execution of print recording, the carriage 84 is periodically moved to a position where the ink jet head 70 faces the purge cap 88 at an appropriate frequency to perform a recovery operation. These series of operations are shown in FIG.
This is performed under the overall control of the CPU 32 inside.

The amount of ink remaining in the ink tank 71 is reduced by performing such a print recording operation. The ink remaining amount detecting circuit 40 detects this. The detection of the remaining amount of ink is performed before and after the recovery operation at the position where the inkjet head 70 faces the purge cap 88. This is because the recovery operation is performed periodically, and the pair of electrodes 72 and 73 for detecting the remaining amount is provided at a position near the platen roller 81 near the purge cap 88. That is, when the carriage 84 moves from the print recording area (the area facing the platen roller 81) to the recovery position (the position where the recovery operation is performed) for the recovery operation of the inkjet head 70, and print recording from the recovery position. When moving toward the area, each ink tank 71 always passes between the electrodes 72 and 73, and at that time, the remaining ink amount is detected.

The detection of the remaining amount of ink for each ink tank 71 by the remaining ink amount detection circuit 40 is performed as follows. When a certain ink tank 71 is located between the electrodes 72 and 73, the capacitance between the electrodes 72 and 73 differs depending on the remaining amount of ink in the ink tank 71. That is, since the ink has a relative dielectric constant of about several tens to one hundred and several tens and is larger than the relative dielectric constant of air, the closer the ink amount of the ink tank 71 is almost full, the larger the capacitance becomes, and the remaining ink amount decreases. The closer to the end of the ink, the smaller the capacitance. The capacitance is detected by a CR oscillation circuit including the logic IC 45, the timing resistor 43, and the capacitor C, and a pulse having a frequency corresponding to the capacitance is output from the logic IC 45 to the CPU 32. And C
By counting the frequency of the pulse by the PU 32, the remaining amount of ink in the ink tank 71 is detected.
Here, since the width E of the electrodes 72 and 73 is equal to or smaller than the width T of the ink tank 71, the remaining ink amount is detected without being affected by the adjacent ink tank 71.

Therefore, when the four ink tanks 71 pass the positions of the electrodes 72 and 73 one after another due to the carriage movement, if the capacitance between the electrodes 72 and 73 is detected in synchronization with the passage, FIG. As shown in the graph of FIG. 10, the remaining amount of ink for each ink tank 71 is detected as a change over time in capacitance. 9, from time t ₁ to time t ₂ is yellow, from time t ₂ to time t ₃ is magenta, from time t ₃ to time t ₄ is cyan, from time t ₄ to time t ₅ Black , The capacitance corresponding to the remaining amount of ink is shown. FIG. 10 shows a case where the direction of carriage movement is reversed. This measurement is
This is performed by controlling the ink remaining amount detection circuit 40 in synchronization with the carriage movement. The control is included in the overall control by the CPU 32.

In FIGS. 9 and 10, before time t ₁ and after time t ₅ , there is no ink tank 71 between the electrodes 72 and 73, and the capacitance due to air only appears. Then, C ₀ shown by a dashed line in FIGS.
Indicates the capacitance due to the contribution of the empty ink tank and the air. Therefore, if the capacitance is close to C ₀ , it means that the remaining amount of ink in the ink tank 71 is small and the ink is almost out. 9 and 10, the cyan ink tank is still almost full, but the yellow ink tank and the black ink tank are almost out of ink.

As described in detail above, according to the ink jet recording apparatus 10 of the present embodiment, the pair of mutually insulated electrodes 72 and 73 are connected to the purge cap 88.
The ink tank 71 is provided between the electrodes before and after the carriage is moved to a position where the ink-jet head 70 performs the recovery operation. Since the capacitance between the ink tanks 71 is detected.
The remaining amount of ink can be periodically detected every time. For this reason, the ink tank 71 approaching the ink shortage can be replaced with a new one before the ink shortage actually occurs and the print recording becomes impossible, which is convenient. At that time, the ink tank 71 to be replaced itself may be a normal product without an electrode.
Excellent compatibility, cost performance and resource saving.

Further, since the width E of the electrodes 72 and 73 is equal to or smaller than the width T of the ink tank 71, the remaining amount of ink in each ink tank 71 can be increased without being affected by the adjacent ink tank 71. Since the detection can be performed with high accuracy, and the ink tanks 71 are measured at the timing when each ink tank 71 comes to a position sandwiched between the electrodes 72 and 73 in synchronization with the movement of the carriage, the remaining ink amount can be detected for each ink tank 71. For this reason, only the ink tank 71 which is almost out of ink can be replaced with a new one, and there is no waste.

It should be noted that the present invention is not limited to the above-described embodiment, and it is needless to say that various improvements and modifications can be made without departing from the gist of the present invention. For example, the ink colors of the respective ink tanks 71 and the arrangement order thereof are merely examples. Further, instead of changing the ink color of each ink tank 71, the present invention can be applied to a device that can support various recording media by changing the viscosity and the like. Further, the circuit configuration of the ink remaining amount detection circuit 40 may be different from that of FIG. 8 as long as it has the same function.

[0031]

As is apparent from the above description, claim 1
According to the invention, the ink tank can be replaced without wasting without replacing the electrode, a pair of electrodes can be used for a plurality of ink tanks, and the ink tank for a conventional type ink jet recording apparatus is directly mounted. An ink jet recording apparatus capable of detecting the remaining amount of ink has been provided. Further, according to the second aspect of the present invention, there is provided an ink jet recording apparatus capable of detecting the remaining amount of ink for each ink tank and identifying an ink tank which is almost out of ink. Further, according to the invention of claim 3, the remaining amount of ink in the ink tank is
2. Description of the Related Art There is provided an ink jet recording apparatus capable of detecting with high accuracy without being affected by another adjacent ink tank. According to the fourth aspect of the present invention, there is provided an ink jet recording apparatus capable of detecting a remaining amount of ink in an ink tank by forming a pair of electrodes as a capacitor.

[Brief description of the drawings]

FIG. 1 is a schematic perspective view of an ink jet recording apparatus according to an embodiment.

FIG. 2 is a diagram illustrating a positional relationship between an ink tank and electrodes.

FIG. 3 is a diagram illustrating a positional relationship between an ink tank and an electrode.

FIG. 4 is a diagram illustrating a positional relationship between an ink tank and an electrode.

FIG. 5 is a diagram illustrating a positional relationship between an ink tank and electrodes.

FIG. 6 is a diagram illustrating a positional relationship between an ink tank and electrodes.

FIG. 7 is a block diagram of a control system of the inkjet recording apparatus according to the present embodiment.

FIG. 8 is a diagram illustrating a circuit configuration of an ink remaining amount detection circuit.

FIG. 9 is a graph showing the capacitance detected for each ink tank.

FIG. 10 is a graph showing the capacitance detected for each ink tank.

[Description of Signs] 40 Ink remaining amount detection circuit 71 Ink tank 72, 73 Electrode 84 Carriage E Electrode width T Ink tank width

Claims (4)

[Claims] 1. An ink jet recording apparatus comprising: a carriage movable in a recording direction; and a plurality of ink tanks mounted on the carriage, wherein the ink in each ink tank is ejected onto a recording medium to perform recording. A pair of electrodes provided in parallel with a recording direction and opposed to each other with the ink tank interposed therebetween at a predetermined position within a range where each of the ink tanks can be located by movement of the carriage, and between the pair of electrodes. An ink jet recording apparatus comprising: a capacity measuring unit for measuring a capacitance; and detecting a remaining amount of ink in each of the ink tanks based on a measurement value of the capacity measuring unit. 2. The ink jet recording apparatus according to claim 1, wherein the capacity measuring unit is arranged between the pair of electrodes when each of the ink tanks reaches the predetermined position in synchronization with the movement of the carriage. An ink jet recording apparatus characterized by measuring a capacitance at each timing and detecting a remaining ink amount for each ink tank. 3. The ink jet recording apparatus according to claim 1, wherein a width of the electrode is equal to or less than a minimum width of a surface of the ink tank facing the electrode. . 4. The ink jet recording apparatus according to claim 1, wherein the pair of electrodes are insulated from each of the ink tanks.