Source: https://patents.justia.com/patent/6796627
Timestamp: 2019-06-19 06:42:07
Document Index: 663369282

Matched Legal Cases: ['art 41', 'art 41', 'art 41', 'art 41', 'art 41', 'art 26', 'art 26', 'art 26', 'art 26', 'art 85', 'art 85', 'art 85']

US Patent for Ink jet recording apparatus, method of replenishing ink to subtank in the apparatus, and method of checking the replenished amount of ink Patent (Patent # 6,796,627 issued September 28, 2004) - Justia Patents Search
Justia Patents Fluid Content (e.g., Moisture Or Solvent Content, Ink Refilling, Liquid Level)US Patent for Ink jet recording apparatus, method of replenishing ink to subtank in the apparatus, and method of checking the replenished amount of ink Patent (Patent # 6,796,627)
Jul 5, 2001 - Seiko Epson Corporation
In an ink jet recording apparatus, a recording head is mounted on a carriage which reciprocately moves in a widthwise direction of recording paper. A subtank is mounted on the carriage for supplying ink. A main tank stores ink which is replenished to the subtank. An ink amount detector detects an amount of ink stored in the subtank. A replenishment controller controls replenishment of ink stored in the main tank to the subtank, in accordance with the ink amount detected by the ink amount detector.
This is a continuation-in-part application of PCT/JP00/07783 filed on Nov. 6, 2000, which was published under PCT Article 21(2) in Japanese and the complete disclosure of which is incorporated into this application by reference.
This invention relates to an ink jet recording apparatus wherein a subtank for supplying ink to a recording head is mounted on a carriage on which the recording head is mounted, and the subtank is replenished with ink in succession from a main tank via an ink replenishing tube, a method of replenishing ink to the subtank, and a method of checking the replenished amount of ink to the subtank.
It is therefore an object of the invention to provide an ink jet recording apparatus capable of properly managing the amount of ink with which a subtank is replenished from a main tank, a method of replenishing ink to a subtank in the recording apparatus, and a method of checking the replenished amount of ink to the subtank.
Embodiments of ink jet recording apparatuses according to the invention will be discussed with reference to the accompanying drawings.
Subtanks 7a to 7d for supplying ink to the recording head 6 are also mounted on the carriage 1. In the embodiment, to temporarily store inks in the subtanks, four subtanks 7a to 7d are provided in a one-to-one-correspondence with the inks.
Black ink, yellow ink, magenta ink, and cyan ink are supplied to the subtanks 7a to 7d via flexible ink replenishing tubes 10 forming ink supply passages from main tanks 9a to 9d as ink cartridges placed in a cartridge holder 8 placed at an end part of the recording apparatus.
On the other hand, a capping unit 11 capable of sealing a nozzle formation face of the recording head is placed in a non-print area (home position) on the move passage of the carriage 1 and further a cap member 11 a formed of a flexible material of rubber, etc., capable of sealing the nozzle formation face of the recording head is placed on the top of the capping unit 11. When the carriage 1 moves to the home position, the nozzle formation face of the recording head is sealed by the cap member 11a.
The cap member 11a serves as a lid for sealing the nozzle formation face of the recording head 6 for preventing nozzle openings from drying, during the non-operating period of the recording apparatus. One end of a tube in a suction pump (tube pump) is connected to the cap member 11a although not shown in the figure, and the cleaning operation of causing a negative pressure produced by the suction pump to act on the recording head for sucking and discharging ink from the recording head 6 is executed.
Next, FIG. 2 schematically shows the configuration of an ink supply system installed in the recording apparatus shown in FIG. 1. The ink supply system will be discussed together with FIG. 1 with the same numerals shown. In FIGS. 1 and 2, air compressed by an air compressing pump 21, which forms a part of a compressor unit, is supplied to a pressure regulating valve 22 also serving as an atmospheric release valve, and further is supplied via a pressure detector 23 to the main tanks 9a to 9d (denoted representatively by numeral 9 in FIG. 2 and in the description to follow, the main tanks may be representatively denoted simply by numeral 9).
The pressure regulating valve 22 also serving as an atmospheric release valve has a function of releasing pressure for maintaining the air pressure applied to each of the main tanks 9a to 9d in a predetermined range when the air pressure compressed by the air compressing pump 21 reaches a predetermined pressure or more. The pressure release valve also has a function capable of releasing the compressed state produced by the air compressing pump 21 in response to an instruction.
Further, the pressure detector 23 senses the air pressure compressed by the air compressing pump 21 and controls driving the air compressing pump 21. That is, if the pressure detector 23 detects the air pressure compressed by the air compressing pump 21 reaching the predetermined pressure, it stops driving the air compressing pump 21 and if the pressure detector 23 detects the air pressure compressed by the air compressing pump 21 becoming less than determined pressure, it drives the air compressing pump 21, and this control sequence is repeated, thereby maintaining the air pressure applied to each of the main tanks 9a to 9d in the predetermined range. As the schematic structure of the main tank 9 is shown in FIG. 2, the outer hull of the main tank is hermetically formed and an ink pack 24 formed of a flexible material in which ink is sealed is stored in the main tank. The space formed by the main tank 9 and the ink pack 24 forms an air chamber (pressure chamber) 25 and compressed air via the pressure detector 23 is supplied to the inside of the air chamber 25.
According to the configuration, each ink pack 24 stored in each of the main tanks 9a to 9d undergoes pressurization of the compressed air and an ink flow under a predetermined pressure is produced from each of the main tanks 9a to 9d to each of the subtanks 7a to 7d.
Ink compressed in each of the main tanks 9a to 9d is supplied to each of the subtanks 7a to 7d mounted on the carriage 1 (the subtanks are denoted representatively by numeral 7 in FIG. 2 and in the description to follow, the subtanks may be representatively denoted simply by numeral 7) via each of ink replenishing valves 26 and each of the ink replenishing tubes 10 forming an ink replenishing controller.
Although the configuration of the subtank 7 shown in FIG. 2 will be described later in detail, in the basic configuration of the subtank 7, a float member 31 is placed in the subtank and a permanent magnet 32 is attached to a part of the float member 31. Magnetoelectric devices 33a and 33b (in the description to follow, the magnetoelectric devices may be representatively denoted simply by numeral 33) represented by hall devices are placed on a board 34 and are attached to a side wall of the subtank 7.
According to the configuration, the permanent magnet 32 placed on the float member 31 and the hall devices 33a and 33b for producing electric output in response to the magnetic flux density of the permanent magnet 32 following the float position of the float member 31 make up an ink amount detector.
Therefore, for example, if the ink amount in the subtank 7 becomes low, the position of the float member 31 housed in the subtank moves in a gravity direction and the position of the permanent magnet 32 also moves in the gravity direction accordingly. Therefore, the electric output of the hall devices 33a and 33b as the permanent magnet moves can be sensed as the ink amount in the subtank 7, and the ink replenishing valve 26 is opened based on the electric output provided by the hall devices 33a and 33b.
Thus, the ink compressed in the main tank 9 is supplied separately to the associated subtank 7 in which the ink amount lowers. If the ink amount in the subtank 7 reaches a predetermined volume, the ink replenishing valve 26 is closed based on the electric output provided by the hall devices 33a and 33b. Such a sequence is repeated, whereby the subtank is replenished intermittently with ink from the main tank and an almost constant amount of ink is always stored in each subtank.
Ink is supplied from each subtank 7 to the recording head 6 via a valve 35 and a tube 36 connected thereto and ink drops are ejected through nozzle openings 6a formed in the nozzle formation face of the recording head 6 based on print data supplied to the recording head 6. In FIG. 2, a tube connected to the capping unit 11 is connected to the suction pump (tube pump) not shown. Numeral 7e denotes an atmospheric release port made in the subtank 7.
Next, disposition examples of the permanent magnet and the magnetoelectric device provided for the subtank will be discussed with reference to FIGS. 3 to 9. FIGS. 3A and 3B show a state in which the subtanks having the described configuration are arranged in parallel for making up a subtank unit and shows a mode in which the hall device 33 as the magnetoelectric device is disposed on the side wall of each subtank as a schematic drawing. FIG. 3A is a sectional view taken along a line E—E in FIG. 3B viewed in the arrow direction. FIG. 3B is a sectional view of a state in which one of the subtanks making up the subtank unit is cut in a plane direction. The subtank unit supported in a parallel state is housed in a holder 81. It comprises a board holder 82 having engagement members 82a for engaging with fitting holes 81a made in the holder 81, and the hall device 33 is placed on the side wall part of each subtank 7 in an urged state by a plurality of springs 83 placed between the board holder 82 and the board 34 on which the hall devices 33 are arranged. In the disposition example, the case where one hall device 33 is provided for each subtank is taken as an example, but two hall devices may be provided for each subtank, as described above.
In this case, as shown in the figure, the subtank 7 is formed in the side wall with a recess part 41c for positioning the hall device 33 and the recess part 41c for positioning is formed, whereby the side wall part of the subtank 7 is made thinner and the distance between the moving path of the permanent magnet 32 attached to the float member 31 and the hall device 33 can be made shorter.
In this case, the subtank 7 is formed of a thermoplastic resin and is previously formed on the side wall part with a pair of projections 41d as shown in FIG. 4A. On the other hand, the board 34 on which the hall device 33 is mounted is formed with a pair of through holes 34a at the positions corresponding to the pair of projections 41d.
As shown in FIG. 4A, the through holes 34a made in the board 34 are inserted into the projections 41d and in this state a heated jig (not shown) is pressed against the projections 41d as indicated by arrows F, whereby the projections 41d are melted and become deformed like flat plates because of the thermoplastic property for holding the board 34 on the side wall part of the subtank 7 as shown in FIG. 4B.
Also in the example shown in the figures, the recess part 41c for positioning the hall device 33 is formed, whereby the side wall part of the subtank 7 is made thinner and the distance between the moving path of the permanent magnet 32 attached to the float member 31 and the hall device 33 can be made shorter.
In other words, as the distance between the moving path of the permanent magnet 32 and the hall device 33 is narrower, the detection sensitivity relative to of the displacement of the permanent magnet 32 can be enhanced and the detection accuracy of the remaining flow amount of ink in the subtank can be more improved. Therefore, the subtank 7 is formed in the side wall with the recess part 41c for positioning the hall device 33 and the side wall part of the subtank 7 is made thin in the presence of the recess part 41c for positioning, so that the detection accuracy of the remaining flow amount of ink in the subtank can be more improved.
However, in the configuration of placing a plurality of hall devices for generating output signals different in phase as the permanent magnet placed on the float member moves, the mode shown in FIG. 6 is effective. This configuration is shown schematically in FIG. 8. That is, on the side wall of the subtank 7, two hall devices 33a and 33b are placed along the moving path of the permanent magnet placed on the float member. According to the mode, taking a state in which the subtank is replenished with ink as an example, as the float member moves (rises) in the anti-gravity direction following replenishing with ink, first a large magnetic force acts on the second hall device 33b and if replenishing with ink is further continued, large magnetic force acts on the first hall device 33a.
Therefore, outputs of the hall devices 33a and 33b are converted into binary signals based on a predetermined threshold voltage, combinations of (00), (01), (11), and (10) can be provided and it is made possible to recognize the ink amount in the subtank with good accuracy. For example, if the ink amount in the subtank is gradually decreased by the print operation, it can also be recognized with good accuracy.
In the modes shown in FIGS. 8 and 9, the distance between the center parts of the hall devices 33a and 33b is shown as L3. In both the configurations, for example, if L1 is 50 mm and L2 is 25 mm and L3 is 5 mm, comparison of the detection accuracy between the first and second hall devices 33a and 33b is as follows:
In the configuration shown in FIG. 8, the difference between the distance between the permanent magnet 32 and the first hall device 33a when the permanent magnet 32 faces the first hall device 33a and the distance between the permanent magnet 32 and the second hall device 33b when the permanent magnet 32 faces the second hall device 33b, namely, W1 shown in FIG. 8 becomes 0.25 mm.
On the other hand, in the configuration shown in FIG. 9, the difference between the distance between the permanent magnet 32 and the first hall device 33a when the permanent magnet 32 faces the first hall device 33a and the distance between the permanent magnet 32 and the second hall device 33b when the permanent magnet 32 faces the second hall device 33b, namely, W2 shown in FIG. 9 becomes 0.51 mm.
As the widths of the W1 and W2 are larger, variations occur in detection in the first and second hall devices 33a and 33b and particularly, to detect the ink amount in the subtank in the four-combination state resulting from converting the outputs of the hall devices 33a and 33b into binary signals based on the predetermined threshold voltage as described above, it is ideal that the W1 and W2 are nearer to zero.
As seen from the description above, the recording apparatus comprises the float member 31 housed in the subtank 7 and floating up in accordance with ink stored in the subtank 7, the magnetoelectric device 33 (33a, 33b) as an output generator for generating electric output following the float position of the float member 31 responsive to the ink amount in the subtank 7, and the ink replenishing valve 26 as supply controller for controlling the amount of ink supplied to the subtank in accordance with the electric output provided by the output generator, and thus the subtank 7 is replenished with ink in succession from the main tank 9 in response to the ink storage amount in the subtank 7. Therefore, a proper amount of ink is stored in the subtank while print is continued, so that it is made possible for even a recording apparatus with a long scanning distance capable of printing on a large-scaled paper face, for example, to stably execute print without degrading throughput.
A concept as shown in FIGS. 10A and 10B can be adopted as a method of setting the ink-low state detection level. FIGS. 10A and 10B schematically show the state of the subtank in an ink-low state condition. First, FIG. 10A shows a state in which the ink volume in the subtank corresponding to a predetermined value (ink-low state) detected by the ink amount detector is set to an amount equal to or greater than the amount of ink consumed by one cleaning operation. In this case, the remaining ink amount in the subtank at the ink-low state detection level is shown as (A). Letting the amount of ink consumed by one cleaning operation be (B), if the ink-low state level is set so that the relation of A&gE;B is set, the subtank can be prevented from becoming empty of ink if the cleaning operation is executed just before the ink amount detector detects the ink-low state.
Therefore, if the ink-low state level is set so that the relation of (A′&plus;C)&gE;B is satisfied, the subtank can be prevented from becoming empty of ink if the cleaning operation is executed just before the ink amount detector detects the ink-low state. In other words, the relation of A′&gE;(B−C) as mentioned above is satisfied. Thus, the ink-low state level detected by the ink amount detector can be set to a lower level than that shown in FIG. 10A, and it is also made possible to design the capacity of each subtank mounted on the carriage as a small size.
An ink tap 71 is formed integrally with the ink pack 24 stored in the main tank 9 and is attached so as to project from one end part of the main tank 9 to the outside. A packing member 71a formed like a ring is placed at the tip part of the ink tap 71 and a valve member 71b placed slidably in an axial direction in the ink tap 71 is urged to the side of the packing member 71a by a spring 71c.
According to the configuration, if the main tank 9 is not placed in the cartridge holder 8, the valve member 71b abuts the packing member 71a so that leaking out ink from the ink pack 24 can be blocked. In the state shown in the figure, the valve member 71b is pushed in by a hollow needle described later and ink can be derived from the ink pack 24.
On the other hand, a connection plug 73 is formed to project at the center of the cartridge holder 8. A hollow needle 73b formed with an ink inlet hole 73a in the vicinity of the tip part is placed in the connection plug 73 and further a slider 73c placed slidably in the axial direction is provided so as to surround the outer periphery of the hollow needle 73b. The slider 73c is urged so as to forward project by a spring 73d.
According to the configuration, if the main tank 9 is not placed in the cartridge holder 8, the slider 73c closes the ink inlet hole 73a made in the hollow needle 73b to close the valve. In the state shown in the figure, the slider 73c is pushed in by the connection plug 73 in the cartridge holder 8, the ink inlet hole 73a in the hollow needle 73b is exposed, and ink can be introduced into the hollow needle 73b from the main tank 9.
The outer hull member of the main tank 9 is formed with an inlet port 75 formed of a tubular body communicating with the air chamber (pressure chamber) 25. On the other hand, a compressed air supply plug 77 is disposed in the cartridge holder tank 8 and an annular packing member 77a is placed in the compressed air supply plug 77. Therefore, in the state shown in the figure in which the main tank 9 is placed in the cartridge holder 8, the annular packing member 77a placed in the cartridge holder 8 is brought into intimate contact with and is coupled with the outer peripheral surface of the inlet port 75 formed of a tubular body. Accordingly, the compressed air can be introduced into the air chamber (pressure chamber) 25 of the main tank 9.
The ink replenishing value 26 is disposed at a base end part of the hollow needle 73b disposed in the cartridge holder 8 and the ink replenishing tube 10 is connected via the valve 26, so that the subtank 7 mounted on the carriage 1 can be replenished with ink as described above. (Reference numerals 1 and 7 are shown in FIG. 1.)
The ink replenishing valve 26 comprises a diaphragm valve 26a and its peripheral margin part is sandwiched between a first case 26b and a second case 26c and the diaphragm valve 26a is housed in both the cases. A slide shaft 26d attached to almost the center of the diaphragm valve 26a is attached slidably in the axial direction to the second case 26c. The slide shaft 26d receives a driving force produced by an electromagnetic plunger 79 as an actuator and is driven in a horizontal direction as shown in the figure. Therefore, upon reception of the axial driving force of the slide shaft 26d, almost the center of the diaphragm valve 26a is moved in the horizontal direction.
In the embodiment, the driving force produced by the electromagnetic plunger 79 is transmitted to one end part of a driving lever 78 pivoted via a support shaft 78a and is transmitted to the slide shaft 26d capable of driving the diaphragm valve 26a at an opposite end part of the drive lever.
Further, a spring 26e is placed between the slide shaft 26d and the second case 26c and when the electromagnetic plunger 79 is in a non-activated state, as shown in FIG. 11, the center of the diaphragm valve 26a closes an opening part 26f made in the first case 26b connected to the base end part of the hollow needle 73b to close the valve by the urging force of the spring 26e. When the electromagnetic plunger 79 is activated, as shown in FIG. 12, a driving rod 79a of the electromagnetic plunger 79 is pulled in, whereby the slide shaft 26d is pulled out via the driving lever 78. Therefore, the center of the diaphragm valve 26a leaves the opening part 26f made in the first case 26b and is opened.
Therefore, in the open state of the diaphragm valve 26a as the electromagnetic plunger 79 is activated, ink is introduced from the ink pack 24 into the first case 26b in which the diaphragm valve is placed via an ink flow passage provided by the hollow needle 73b as indicated by the arrow in FIG. 12, and the subtank 7 can be replenished with ink via the ink replenishing tube 10 connected to the first case 26b. When the amount of ink in the subtank 7 reaches the predetermined volume, the electromagnetic plunger 79 is not activated and replenishing with ink is stopped according to output of the hall devices 33a and 33b for detecting the magnetic flux density change of the permanent magnet 32 following the float position of the float member 31 placed in the subtank 7.
If the operation power of the recording apparatus is turned off, the electromagnetic plunger 79 is also placed in a non-activated state, whereby the center of the diaphragm valve 26a closes the opening part 26f made in the first case 26b connected to the base end part of the hollow needle 73b to close the valve by the urging force of the spring 26e, as shown in FIG. 11. Therefore, if a water head difference exists between the main tank 9 and the subtank 7, ink flowing in either direction via the ink replenishing tube 10 can be blocked.
As understood from the configuration shown in FIGS. 11 and 12, the ink flow passage to the opening part 26f of the first case 26b in which the diaphragm valve 26a is placed, namely, the ink flow passage formed in the hollow needle 73b and the ink flow passage from the inside of the case 26b to the ink replenishing tube 10 are made almost orthogonal to each other and the derivation part of the ink replenishing tube 10 connected to the case 26b is placed so as to head for almost in a vertical direction.
According to the configuration, air bubbles entered when the main tank 9 as an ink cartridge is placed in the cartridge holder 8 can be floated toward the ink replenishing tube 10 side without building up in the vicinity of the diaphragm valve 26a. The air bubbles floated toward the ink replenishing tube 10 side are introduced into the subtank 7 and are floated, so that a problem of the air bubbles entering the recording head 6 and causing a print failure to occur can be circumvented.
In the embodiment shown in FIGS. 11 and 12, the ink replenishing valve comprising the diaphragm valve 26a is placed in the cartridge holder 8 in which the main tank is placed. That is, the ink replenishing valve is placed in the close vicinity of the main tank side in the ink replenishing passage from the main tank to the subtank. For example, if the main tank 9 is drawn out from the cartridge holder 8, leaking out ink existing in the ink replenishing tube 10 to the cartridge holder 8 side can be effectively blocked because the ink replenishing valve is placed in the close vicinity of the cartridge holder 8.
In this case, although the cartridge holder 8 comprises the slider 73c for covering the ink inlet hole 73a of the hollow needle 73b to close the valve, placing the ink replenishing valve in the close vicinity of the main tank side can contribute to more effective blocking of leaking out ink from the connection plug 73 in the cartridge holder upon reception of a backward flow caused by the water head difference, because the valve closing function of the ink inlet hole 73a by the slider 73c and the valve closing function by the ink replenishing value 26 work as a synergistic effect.
For example, if the ink amount detector containing the float member malfunctions or some failure occurs in the control signal transmission system from the ink amount detector to the ink replenishing valve in the ink jet recording apparatus configured as described above, an accident occurs in which the ink replenishing valve is not closed although the subtank is replenished with a predetermined amount of ink. If such an accident occurs, the following problem can occur: The subtank is continuously replenished with ink from the main tank by the compressed air and ink leaks via the atmospheric release port 7e formed in the subtank or the like, polluting the surroundings.
First, at step S11, ink level detection in the subtank is executed. It is determined by output of the hall devices 33a and 33b for detecting the magnetic flux density of the permanent magnet attached to the float member as described above.
Here, if the ink amount detector determines that the amount of ink in the subtank is less than a predetermined value, the case is called “LOW” and if the ink amount detector determines that the amount of ink in the subtank reaches a sufficient amount, the case is called “FULL.” If the ink amount is determined “FULL” at step S11, a return mode is entered and subsequently the ink amount is monitored at step S11. If the ink amount is determined “LOW” as the recording head consumes ink, control goes to step S12 and the ink replenishing valve 26 is opened.
Therefore, replenishing the subtank with ink from the main tank is started (ink replenishing step). Subsequently, the ink amount detector monitors the ink amount in the subtank as shown at step S13. Just after the replenishing valve 26 is opened at the step S12, normally the “LOW” state is detected at step S13 and determination shown at step S14 is made.
In the state in which the elapsed time is less than the predetermined time period, the subtank is replenished with ink and if the ink amount is determined “FULL” at step S13, control goes to step S15 at which the ink replenishing valve 26 is closed and a return mode is entered (ink replenishment stopping step). Therefore, the operation shown at steps S11 to S15 is repeated and the subtank is intermittently replenished with ink from the main tank. The operation shown at steps S11 to S15 is repeated when the ink replenishing operation is performed normally.
The routine shown at the step S14 and step S16 following the step controls so as to prevent the subtank from being replenished with an excessive amount of ink assuming occurrence of such a failure. That is, at step S14, the elapsed time period since the ink replenishing valve opening executed at step S12 is monitored as described above, and if it is determined in the loop operation of steps S13 and S14 that “FULL” is not detected, namely, the “LOW” state remains although the predetermined time period has elapsed, control goes to step S16 and the ink replenishing valve 26 is forcibly closed (ink replenishment forcibly stopping step).
A detection switch 29 forming an ink end detector for detecting the amount of ink stored in the main tank becoming a predetermined value or less may be provided in the main tank 9 as also shown in FIG. 15. One face of the ink pack 24 is put on the inner face of the case forming the main tank 9, for example, with a double-faced adhesive sheet and an actuation plate 24b is put on another face of the ink pack 24 in a similar manner. According to the configuration, if the amount of ink sealed in the ink pack 24 becomes low, a part of the actuation plate 24b functions so as to turn on the detection switch 29, for example, as the ink pack 24 contracts.
If the ink volume in the subtank 7 becoming a predetermined value (almost fill-up state) as the subtank is replenished with ink is detected based on electric output of the hall devices 33a and 33b, the ink replenishing valve 26 is closed as mentioned above, and at the same time, the count of the subtank consumed ink counter 109 is reset.
A control signal sent to open the ink replenishing valve 26 from the subtank consumed ink counter 109 is supplied to a timer 112. The timer 112 starts to count the time period at the same time as the ink replenishing valve 26 is opened. It receives output of the hall devices 33a and 33b occurring when the subtank 7 is placed almost in a fill-up state.
Upon reception of the control signal sent to open the ink replenishing valve 26, the timer 112 starts to count the time period, and if the output of the hall devices 33a and 33b occurring when the subtank 7 is placed almost in a fill-up state does not come although a predetermined time period has elapsed, the timer 112 causes a display 113 to display a message, etc., indicating that the main tank is in an ink end condition.
Concretely, when the ink end information is transferred from the timer 112 to the main tank residual ink counter 110, information regarding the residual ink amount or the consumed ink amount is converted into an residual ink value corresponding to the ink end state (e.g., numeric information “0”), or a consumed ink value corresponding to the ink end state (e.g., numeric information “100” if the capacity of the main tank is 100 cc). The converted value is written in the memory 27 via the reader/writer 111.
As a result, when the main tank is again loaded on the recording apparatus, it can be read out that the residual ink amount in the main tank is “0”, so that the ink end state of the loaded main tank can be immediately recognized. In a case where the main tank residual ink counter 110 deals with the information regarding the consumed ink amount, the ink end state of the loaded main tank can be immediately recognized if the read out value indicating the consumed ink amount reaches “100”.
In the above case where the numeral data in the main tank residual ink counter 110 is incrementally or decrementally controlled by utilizing the function of the consumed ink amount calculator 107, there is probability that the residual ink value reaches “0” even though the main tank is actually in the ink end state, due to a margin of error in the consumed ink amount measured by the consumed ink amount calculator 107. Similarly, there is probability that the consumed ink value reaches “100” which is the capacity of the main tank.
To solve the above problem, it is preferable to configure the main tank residual ink counter 110 so that the decrement of the count is stopped when the count closes to the value corresponding to the ink end state (e.g., “0”), and so that the counted value is rewritten to “0” when the ink end information is sent from the timer 112. Accordingly, the ink end information can be precisely written in the memory 27 under a condition where the main tank is actually in the ink end state.
Similarly, in a case where the main tank residual ink counter 110 deals with the information regarding the consumed ink amount, it is preferable to configure the main tank residual ink counter 110 so that the increment of the count is stopped when the count closes to the value corresponding to the ink end state. For example, in a case where the value corresponding to the ink end state is “100”, the increment of the count is stopped at “99”. And main tank residual ink counter 110 is configured so that the counted value is rewritten to “100” when the ink end information is sent from the timer 112.
This is to check whether or not the count of the subtank consumed ink counter 109 shown in FIG. 16 exceeds the predetermined value (A). If it is determined that the count does not exceed the predetermined value (A) (No), the ink volume in the subtank has a margin. Therefore, control returns until the count exceeds the predetermined value (A), and the routine at the steps S11 and S12 is repeated. If it is determined at the step S12 that the numeric value of the subtank consumed ink counter 109 exceeds the predetermined value (A), control goes to step S13 and the operation of replenishing the subtank with ink is started. This is performed by opening the ink replenishing valve 26. Subsequently, at step S14, whether or not replenishing the subtank with ink is complete is checked. To do this, output of the hall devices 22a and 33b is used as described above.
First, FIGS. 18A and 18B show a configuration wherein a case of an ink cartridge 9 is molded of a transparent resin and a prism part 85 is formed at a corner between the lower bottom portion and the side wall portion of the case. That is, the incidence angle on the print part 85 from the light source 86 and the outgoing angle from the prism part 85 to the sensor 87 are set to each an angle of &thgr; (&equals;45 degrees). The residual amount of ink in the ink cartridge is detected based on the difference between the critical angle of total reflection determined by the flexion ratio between the ink in the cartridge 9 and the resin forming the case and the critical angle of total reflection determined by the flexion ratio between air and the resin forming the case.
Further, FIG. 20 shows a configuration wherein a pair of electrode terminals 90a and 90b is buried toward the storage space of ink in the proximity of the lower bottom face of a case of an ink cartridge 9 and a predetermined voltage is applied to one electrode terminal 90a from a constant-voltage source 91. A resistor 92 is connected to the other electrode terminal 90b between the electrode terminal and reference potential (ground) and a voltage detector 93 for detecting a potential occurring at the resistor 92 is connected to the other electrode terminal 90b mentioned above.
Next, there will be described a method of checking whether the overflow condition is erroneous detection of the ink level caused accidentally by a factor as mentioned above or an overflow condition caused by a true failure, in a case where the ink amount detector comprising the two hall devices 33a and 33b described above detects an overflow condition of ink. A control circuit is basically the same as that shown in FIG. 16 and therefore flowcharts are used for the description to follow.
FIG. 21 is a flowchart to show the basic concept of a first checking method. That is, first as shown at step S11, whether or not subtank is in an overflow condition is checked based on the output combination of the two hall devices 33a and 33b making up the ink amount detector. If it is determined that the subtank is not in an overflow condition (No), control is returned and a similar determination is repeated from the start.
Next, FIG. 22 is a flowchart to show the basic concept of a second checking method when the ink amount detector detects an ink overflow condition. In the second checking method, the operation of sucking and discharging ink from the recording head is executed two or more times and whether or not the subtank is in an ink overflow condition is checked each time the operation of sucking and discharging ink is executed. That is, as shown at step S21, whether or not the subtank is in an overflow condition is checked based on the output combination of the two hall devices 33a and 33b making up the ink amount detector as at the step S11. If it is determined that the subtank is not in an overflow condition (No), control is returned and a similar determination is repeated from the start.
First, when the operation power of the recording apparatus is turned on, a replenishing stop flag is reset as shown at step S31. That is, the replenishing stop flag is reset, whereby it is made possible to replenish the subtank 7 with ink. The amount of ink in the subtank 7 is determined from determination of ink level detection shown at step S33, namely, the output combination of the two hall devices 33a and 33b making up the ink amount detector.
If it is determined at the above-described step S39 that the subtank is not in an overflow condition (No), it can be estimated that in the previous ink level detection operation, vibration, etc., is received and erroneous detection results, as described above. Thus, in this case, a warning containing a message of “do not give vibration,” or the like may be displayed on the display 113.
Control returns to the step S33 and if it is determined at the step S33 that ink is a full condition, the subtank 7 need not be replenished with ink, and control is returned. If it is determined at step S33 that ink is a low condition, control goes to step S42 and the count-up value of the subtank consumed ink counter 109 is referenced. Whether or not the consumed ink amount in the subtank is equal to or greater than “Ch*” is checked.
This “Ch*” is a predetermined value set as a parameter and if it is determined that the count-up value of the consumed ink counter 109 does not reach the predetermined value (No), control is returned. If it is determined that the count-up value of the consumed ink counter 109 reaches the predetermined value (Yes), control goes to the routine of replenishing the subtank 7 with ink.
If the determination at step is “Yes,” control goes to the routine of replenishing the subtank 7 with ink, as described above. At step S43 following step S42, ink level detection operation to monitor the ink level of the subtank based on replenishing with ink is performed. At this point in time, the ink level detection result is almost always low and at step S44, the replenishing valve 26 is opened and replenishing the subtank 7 with ink from the main tank 9 is started.
At step S45, whether or not a time period in which the ink low condition has been continued reaches a predetermined value is checked. In other words, here the elapsed time period after the replenishing valve 26 was opened at step S44 is measured by the timer 112 shown in FIG. 16. At this point in time, the ink level low duration does not reach the predetermined time period and the determination is “No”. Therefore, control again returns to step S43 via a loop of (A) shown in FIG. 23 and the state of replenishing the subtank 7 with ink is monitored. That is, the ink replenishing routine from step S43 to S45 is repeated. If it is determined at step S43 that the ink level of the subtank becomes a full condition, control goes to step S46.
The ink supplying pump 38 is driven appropriately in response to the detection state of ink amount detector made up of a combination of a permanent magnet 32 on a float member 31 placed in the subtank 7 and hall devices 33a and 33b.
According to the configuration, if it is recognized that the amount of ink in the subtank 7 lowers based on the electric output provided by the hall devices 33a and 33b, the ink supplying pump 38 corresponding to the subtank is driven, whereby the subtank is replenished with ink separately from the main tank. If the amount of ink in the subtank 7 reaches a predetermined volume, driving the ink supplying pump 38 is stopped based on the electric output of the hall devices 33a and 33b mentioned above. Such a sequence is repeated, whereby the subtank is replenished intermittently with ink from the main tank and an almost constant amount of ink is always stored in each subtank.
FIG. 26 is a block diagram to show the third embodiment. A subtank unit 7 is implemented as a vessel comprising an atmospheric release port 7e and an ink supply port 10a in the top and a float member 31 for detecting an ink level is placed in the vessel. A magnetic substance 32 is placed on the float member 31 and magnetoelectric devices 33a and 33b each as a sensor for detecting the magnetic substance 32 are placed at positions facing the upper and lower limits of the ink level.
Pump controller 121 controls a flow amount so that the ink level in the subtank unit becomes at least above the lower limit value and below the upper limit value based on signals from the magnetoelectric devices 33a and 33b as sensors, and drives an air pump 120 in response to ejection by head driver 101.
In the embodiment, when the subtank unit 7 is not replenished with ink, the pump controller 121 drives the air pump 120 based on the signals from the magnetoelectric devices 33a and 33b as replenishing sensors for the subtank 7 with ink in an ink cartridge 9 to a stipulated level.
An ink replenishing method capable of properly maintaining the ink level in the subtank 7 using the magnetoelectric devices 33a and 33b as sensors and judgement circuit in the third embodiment described above will be discussed with reference to FIG. 28.
As shown in FIG. 28, the magnetoelectric devices 33a and 33b as sensors are placed with a spacing of &Dgr;H1&plus;&Dgr;H2 so that ink in the subtank 7 can be detected above and below stipulated level L0 and a magnetic field of the permanent magnet 32 as an indicator can be detected in a predetermined range, namely, a range A (&equals;&Dgr;A1&plus;&Dgr;A2) in which the ink level should be maintained at the same time.
Accordingly, if the float member 31 moves down more than &Dgr;A1 below the position corresponding to the stipulated level L0, the magnetic field of the indicator 32 does not act on the upper magnetic sensor 33a and the fact that the ink level decreases to the liquid amount requiring pouring can be detected, and if the float member 31 moves up more than &Dgr;A2 above the position corresponding to the stipulated level L0, the magnetic field of the indicator 32 does not act on the lower magnetic sensor 33b and the fact that the ink level reaches the liquid amount to stop pouring can be detected.
That is, in the range of &Dgr;A1&plus;&Dgr;A2 in which the ink level should be maintained properly, the magnetic flux distribution of the indicator 32, the sensitivities of the magnetic sensors 33a and 33b, and the placement spacing &Dgr;H1&plus;&Dgr;H2 therebetween are adjusted so that the magnetic field of the indicator 32 acts on the two magnetic sensors 33a and 33b at the same time.
The range of &Dgr;A1&plus;&Dgr;A2 in which the ink level should be maintained becomes narrow if the spacing between the magnetic sensors 33a and 33b is widened, and the range becomes wide if the spacing is lessened. If an indicator having a large magnetic flux distribution in an up and down direction is used as the indicator 32, the range in which the ink level should be maintained can be enlarged.
The float member is formed on the top with a projection 31a (see FIGS. 26 and 27) for defining the upper limit position of the float member 31 regardless of a rise in the ink level, and the projection 31a abuts the upper face of the subtank 7 for limiting the rise position of the float member 31 and preventing the float member 31 from moving outside the detection range of the magnetic sensor 33a.
In the embodiment, the float member is formed with the projection 31 a for regulating the upper limit, but if the subtank is formed with a projection, a similar advantage can also be provided.
A judgement circuit 123 for receiving signals from the magnetic sensors 33a and 33b assumes that ink is of a too small amount, and outputs a first error signal if the first and second magnetic sensors 33a and 33b output both low signals (in the embodiment, the low signal means a state in which a magnetic flux is not detected and a high signal means a state in which a magnetic flux is detected).
If a high signal is output only from the first magnetic sensor 33b at the lower position, a pouring start signal is output.
Further, high signals are output from both the first and second magnetic sensors 33a and 33b, the liquid amount is maintained properly and therefore a pouring stop signal is output.
Further, if a high signal is output only from the second magnetic sensor 33a at the upper position, it is assumed that ink is oversupplied, and a second error signal is output.
Such control is performed, whereby the ink level in ink supply unit 3 is maintained in the range of −&Dgr;A1 to &plus;&Dgr;A2 sandwiching the stipulated level L0 therebetween and ink can be supplied to the recording head 4 at the water head difference appropriate for print.
By the way, if the pump 120 (122) continues to operate because of trouble of the pump driver 105 although the judgement circuit 123 outputs a pouring stop signal at replenishing with ink, the float member 31 moves up to a top dead center defined by the projection 31a. In this state, a low signal is output from the first magnetic sensor 33b and a high signal is output from the second magnetic sensor 33a and thus the judgement circuit 123 outputs a second error signal to the forcible stopper 125 for shutting down the operation power supplied to the pump 120 (122) and forcibly stopping pouring of ink, thereby preventing an overflow.
If a larger amount of ink than the stipulated amount is thus poured, the float member 31 is stayed at the given upper limit position by the projection 31a, so that the magnetic field of the indicator 32 acts on the second magnetic sensor 33a and the state can be distinguished from the state in which ink becomes too small. That is, if the upper limit position of the float member 31 is not regulated, the indicator 32 moves to a position at which the magnetic field of the indicator 32 does not act on the second magnetic sensor 33a, and the state cannot be distinguished from the state in which ink becomes too small.
a recording head, mounted on a carriage which reciprocally moves in a widthwise direction of recording paper;
a non-flexible subtank formed with an airhole, mounted on the carriage for containing ink therein;
an ink amount detector, which detects an amount of ink stored in the subtank;
a replenishment controller, which controls replenishment of ink stored in the main tank to the subtank, in accordance with the ink amount detected by the ink amount detector; and
a compressor, which maintains the main tank in a compressed state,
wherein the replenishment controller includes an ink replenishing valve which is opened or closed by a control signal generated by the ink amount detector for replenishing ink stored therein to the subtank, and
wherein the ink amount detector includes a float member floating on the ink stored in the subtank, and an output generator which generates an electrical output in accordance with a floating position of the float member, which changes according to the stored ink amount.
2. The recording apparatus as set forth in claim 1, wherein the replenishment controller blocks ink communication when an operation power of the apparatus is turned off.
wherein a first ink supply passage connecting the main tank and the diaphragm valve and a second ink supply passage connecting the diaphragm valve and the ink replenishing tube are arranged so as to extend perpendicularly to each other.
7. The recording apparatus as set forth in claim 3, wherein the actuator is an electromagnetic plunger.
wherein a driving force of the electromagnetic plunger is acted on one end of the lever member so that the driving force is transmitted to the slide shaft via the other end of the lever member.
9. The recording apparatus as set forth in claim 7, wherein the diaphragm valve is opened when the electromagnetic plunger is activated, and is closed when the electromagnetic plunger is not activated.
wherein two magnetoelectric elements are arranged above and below a predetermined level of ink such that both elements are able to detect the magnetic flux generated from the permanent magnet so that three ink levels are recognized.
14. The recording apparatus as set forth in claim 13, wherein the magnetoelectric elements are arranged such that the following states are recognized by the output signals therefrom:
a first state indicating an ink end state
a second state indicating the ink replenishment needs starting;
a third state indicating the ink replenishment needs terminating; and
a fourth state indicating an ink overflow state.
15. The recording apparatus as set forth in claim 1, further comprising a timer, which starts counting a time period when an ink replenishing valve is opened;
wherein the ink amount detector includes a consumed ink amount calculator, which calculates an ink amount consumed in the subtank;
wherein the ink replenishing valve is opened when the consumed ink amount calculated by the consumed ink amount calculator is a predetermined value or more
wherein the ink replenishing valve is closed when the ink amount detector detects that the replenished ink amount in the subtank is a predetermined level or more, which indicates an ink full state; and
wherein the ink amount detector includes an ink end detector which determines that the main tank is in an ink end state when the ink amount detector does not detect the ink full state, even if the timer counts a predetermined time period.
16. The recording apparatus as set forth in claim 15, wherein the ink amount detector includes a residual ink amount detector, which detects an ink amount remaining in the main tank,
wherein the determination of the ink end detector is made effective when the residual ink detector detects that the residual ink amount is a predetermined amount or less.
17. The recording apparatus as set forth in claim 16, wherein the consumed ink amount calculator and the residual ink amount detector respectively calculate the consumed ink amount and the residual ink amount by multiplying coefficients which are respectively provided in association with ink ejection for printing, ink ejection for flushing, and ink suction for cleaning.
wherein the ink overflow state is checked every time when the discharging operation is performed.
24. The recording apparatus as set forth in claim 23, wherein an error condition is recognized when the ink overflow state is detected even after the discharging operation is repeated at a predetermined number of times.
wherein the ink amount detector detects an ink low level which is determined as an ink amount capable of remaining in the subtank even after ink consumption by a single cleaning operation.
33. The recording apparatus as set forth in claim 32, wherein the predetermined amount detected by the ink amount detector is an ink amount consumed by a single cleaning operation or more.
an electrically rewritable memory, provided with the main tank;
a consumed ink amount calculator, which provides information regarding an ink amount consumed in the subtank, which is written in the memory;
a residual ink amount detector, which provides information regarding an ink amount remaining in the main tank, which is written in the memory; and
an ink end detector which provides information regarding whether the main tank is in an ink end state, which is written in the memory.
36. The recording apparatus as set forth in claim 35, wherein the consumed ink amount information and the residual ink amount information are calculated by respectively multiplying the consumed ink amount and the residual ink amount with coefficients which are respectively provided in association with ink ejection for printing, ink ejection for flushing, and ink suction for cleaning.
wherein the increment and the decrement of the numeral values are stopped at second numeral values which is in the vicinity of the first numeral values; and
wherein the second values are converted into the first values when the ink end detector provides information indicating that the main tank is in the ink end state.
40. The recording apparatus as set forth in claim 1, wherein the ink amount detector includes a physical detector, which detects that the main tank is in an ink end state.
a valve member, provided in a flow passage connecting the subtank and the recording head;
a replenishment controller, which controls replenishment of ink stored in the main tank to the subtank, in accordance with the ink amount detected by the ink amount detector,
wherein the replenishment controller is provided in a replenishment passage which connects the main tank and the subtank; and
wherein the replenishment controller includes a pump, which is operated in accordance with the ink amount detected by the ink amount detector, for replenishing ink stored in the main tank to the subtank.
47. The recording apparatus as set forth in claim 46, wherein the replenishment controller includes a pump for replenishing ink stored in the main tank to the subtank, and a pump controller which controls the pump in accordance with a drive signal sent to the recording head.
a replenishment controller, which controls replenishment of ink stored in the main tank to the subtank, in accordance with the ink amount detected by the ink amount detector, further comprising:
a timer, which counts a time period in which the apparatus is not operated;
a discharger, which discharges ink stored in the subtank; and
a refilling controller, which controls the discharger and the replenishment controller so as to discharge ink stored in the subtank and to replenish ink stored in the main tank to the subtank, when the apparatus is recovered from the non-operating state and a time period counted by the timer reaches a predetermined time period.
49. The recording apparatus as set forth in claim 48, further comprising a residual ink amount sensor, which detects an ink amount remaining in the subtank which is in the non-operating state,
wherein the predetermined time period is made shorter as less amount of ink is detected by the residual ink sensor.
50. The recording apparatus as set forth in claim 48, wherein a part of ink left in the subtank is discharged when the apparatus is recovered from the non-operating state.
operating an ink replenishing valve provided in a replenishment passage which connects the main tank and the subtank, so as to be opened and closed repeatedly in a single replenishing operation;
wherein the ink replenishing valve is opened and closed irrespective of the reciprocate movement of the carriage.
52. The replenishing method as set forth in claim 51, wherein the pressure applying step includes the steps of operating the compressor so as to be driven and stopped repeatedly in accordance with a pressure state in an air passage connecting the compressor and the main tank.
wherein the ink replenishing valve is forcibly closed when a predetermined time period is elapsed after the ink replenishing valve is opened.
54. The replenishing method as set forth in claim 53, further comprising the step of displaying an error message, when the ink replenishing valve is forcibly closed.
continuing a printable condition of the apparatus when the ink overflow state is not detected by the checking step; and
determining an error condition of the apparatus when the ink overflow state is detected by the checking step.
56. The checking method as set forth in claim 55, wherein the discharging step includes the steps of
sealing a nozzle formation face of the recording head with a capping member; and
applying therein negative pressure generated by a suction pump.
57. A method of checking replenishment of ink stored in a main tank to a subtank mounted on a carriage reciprocally moving in a widthwise direction of recording paper, together with a recording head, which are incorporated in an ink jet recording apparatus, the method comprising:
detecting an error condition of the apparatus when the detected number reaches the predetermined number.
58. The checking method as set forth in claim 57, wherein the discharging step includes the steps of:
sealing a nozzle formation face of the recording head with a capping member, and
59. A method of checking replenishment of ink stored in a main tank to a subtank mounted on a carriage reciprocally moving in a widthwise direction of recording paper, together with a recording head, which are incorporated in an ink jet recording apparatus, the method comprising:
performing a predetermined amount of printing when it is detected an ink overflow state in which the replenished ink amount detected by the detecting step exceeds a predetermined value,
60. The checking method as set forth in claim 59, wherein the printing step is continued until printing for a subject page is finished.
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Patent number: 6796627
Patent Publication Number: 20020024543
Inventors: Hitotoshi Kimura (Nagano), Atsushi Kobayashi (Nagano), Noboru Tamura (Nagano), Hiroaki Tojyo (Nagano), Yoshiharu Aruga (Nagano), Minoru Usui (Nagano), Kazunaga Suzuki (Nagano), Takashi Mano (Nagano), Toshio Kumagai (Nagano)
Primary Examiner: Juanita Stephens
Application Number: 09/898,080