JP3770307B2 - Inkjet recording device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an ink jet recording apparatus configured to supply ink from an ink cartridge to a recording head mounted on a carriage by supplying pressurized air to the ink cartridge.
[0002]
[Prior art]
An ink jet recording apparatus generally includes an ink jet recording head that is mounted on a carriage and moves in the width direction of the recording paper, and a paper feeding unit that moves the recording paper in a direction perpendicular to the moving direction of the recording head. And recording is performed on the recording paper by ejecting ink droplets from the recording head based on the print data.
[0003]
On the other hand, in this type of recording apparatus provided for office use or business use, for example, a large-capacity ink cartridge needs to be provided in order to cope with a relatively large amount of printing. There is provided a recording apparatus of a type that is loaded into a mounting apparatus (cartridge holder) disposed on the main body side of the apparatus.
[0004]
A sub tank is arranged on the carriage on which the recording head is mounted, and ink is supplied from the main tank as the ink cartridge to each sub tank via an ink supply tube, and each sub tank is supplied to the recording head. In contrast, ink is supplied.
[0005]
[Problems to be solved by the invention]
Nowadays, there is an increasing demand for a large recording apparatus that can perform printing on a large paper surface and has a long carriage scanning distance. In such a recording apparatus, in order to improve the throughput, more and more nozzles are provided in the recording head. Furthermore, in order to improve throughput, it is possible to replenish ink sequentially from the ink cartridge to each sub-tank mounted on the carriage while printing is performed, and the ink is stabilized from each sub-tank to the recording head. And a recording apparatus that can be supplied.
[0006]
In such a recording apparatus, it is necessary to connect an ink supply tube corresponding to each ink from the ink cartridge to the sub tank on the carriage. Since the scanning distance of the carriage is large, the tube is inevitably routed. The distance increases. In addition, as described above, since the recording head has a large number of nozzles, the amount of ink consumed is large, and the dynamic pressure (pressure loss) of ink in each ink supply tube connected from the ink cartridge to the sub tank is high. As a result, there is a technical problem that the amount of ink replenished to the sub-tank is insufficient.
[0007]
As one means for solving such a problem, for example, an ink pack housed in an ink cartridge is pressurized with air, thereby generating an ink flow from the cartridge to the sub tank, and supplying ink to the sub tank. A configuration that enables replenishment is preferably employed. Thus, in a recording apparatus configured to replenish ink from the cartridge by the action of pressurized air, the ink replenishment amount via the ink replenishment tube is the maximum ink ejection amount (full) in the print state of the recording head. It is necessary that the pressure of the pressurized air be set so as to cover the ink discharge amount at the time of duty.
[0008]
On the other hand, a recording head used in this type of recording apparatus has a relationship in which ink pressurized in a pressure generating chamber is ejected as ink droplets from a nozzle opening onto a recording sheet and printing is performed. There is a problem that printing failure occurs due to increase in ink viscosity due to evaporation or solidification of ink. For this purpose, a cleaning operation is performed in which the nozzle forming surface of the recording head is sealed by the capping unit, and the ink is sucked from the nozzle opening by the negative pressure from the suction pump to eliminate the ink ejection failure.
[0009]
When such a cleaning operation is executed, much more ink is consumed than the maximum ink discharge amount in the print state of the recording head. Therefore, when the pressure of the pressurized air is set so as to cover the maximum ink discharge amount in the printing state as described above, the ink in the sub tank is insufficient during the cleaning operation, and a sufficient cleaning effect is exhibited. Can not do it. Furthermore, there is a case where bubbles enter the ink flow path from the sub tank to the recording head, resulting in a severe printing failure state. In order to avoid such a situation, it is necessary to obtain a replenishment flow rate of ink that does not run out of ink in the sub tank even when the cleaning operation is executed. For this reason, it is necessary to set the pressure of the pressurized air applied to the ink cartridge higher.
[0010]
However, when the pressurized air for the ink cartridge is to be set high as described above, it is necessary to improve the function of the pressure pump and to improve the pressure resistance of the ink pack in the cartridge. In addition, it is necessary to ensure the reliability of the pressure resistance in the pressurized air supply system over a long period of time. Therefore, the cost increase to cope with these is inevitable.
[0011]
The present invention has been made based on such a technical viewpoint, and the pressure of the pressurized air can be set to an extent that covers the maximum ink discharge amount in the print state of the recording head. An object of the present invention is to provide an ink jet recording apparatus that can eliminate the shortage of ink during a cleaning operation.
[0012]
[Means for Solving the Problems]
An ink jet recording apparatus according to the present invention made to achieve the above-described object includes a recording head mounted on a carriage and reciprocally moved in the width direction of the recording paper, and mounted on the carriage together with the recording head. And a sub tank for receiving ink from the ink supply path and supplying ink to the recording head. By supplying pressurized air to the ink cartridge, the ink cartridge transfers the ink from the ink cartridge to the sub tank. An ink jet recording apparatus configured to replenish ink, wherein the ink replenishment is performed when the ink amount detecting means detects that the amount of ink stored in the sub-tank has become a predetermined value or less. From the ink cartridge to the sub tank via the Along with the configured to replenish, Even when the ink amount detecting means detects that the amount of ink stored in the sub-tank has become a predetermined value or less during the cleaning operation, ink is replenished from the ink cartridge to the sub-tank via the ink replenishment path. The ink capacity in the sub tank corresponding to the predetermined value detected by the ink amount detecting means is subtracted from the ink consumption by one cleaning operation, the amount of ink replenished in the sub tank during the cleaning operation. The ink replenishment amount to the sub-tank through the ink replenishment path covers the maximum ink discharge amount in the print state of the recording head. The pressure of the pressurized air is set to Characterized by points.
[0014]
On the other hand, the ink amount detection means preferably generates an output that generates an electrical output in accordance with a float member that floats by the ink stored in the sub tank and a float position of the float member according to the ink amount in the sub tank. Means. In this case, the output generating means is preferably composed of a permanent magnet disposed on the float member and a magnetoelectric conversion element that generates an electrical output in accordance with a magnetic force dose by the permanent magnet according to the floating position of the float member. The
[0015]
Valve means disposed in the ink supply path and controlled to open / close in response to an electrical output from the output generating means is provided, and the ink cartridge intermittently moves from the ink cartridge to the sub tank by the opening / closing operation of the valve means. It is configured to be refilled with ink. In this case, preferably, the ink cartridge includes an ink pack formed of a flexible material in which ink is sealed, and a cartridge case formed in an airtight state containing the ink pack. A pressure pump for supplying pressurized air is disposed in a pressure chamber formed between the cartridge case and the ink pack in a state in which is loaded.
[0016]
A flexible ink supply tube is preferably employed as the ink supply path from the ink cartridge to the sub tank. Further, the air pressure of the pressurized air is configured to be managed by a pressure detector that is driven and displaced by the air pressure. In this case, the pressure detector is preferably provided with a diaphragm that is displaced by receiving pressurized air, and an output generating means that generates a control signal based on the displacement of the diaphragm at a set pressure.
[0017]
According to the recording apparatus configured as described above, an ink pack formed of a flexible material in which ink is sealed is stored in a cartridge, and the space formed by the outer case of the cartridge and the ink pack is stored in the cartridge. Since air pressure is applied to the sub tank, ink can be reliably supplied to the sub tank regardless of the occurrence of pressure loss in the ink supply tube from the cartridge to the sub tank. The ink amount detecting means including the float member arranged in the sub tank moves in the gravitational direction according to the amount of ink stored in the sub tank, and senses the magnetic field lines of the permanent magnet arranged in the float member. Based on the output of the conversion element, it is detected that the ink in the sub-tank has become a predetermined value or less (hereinafter also referred to as an ink low state).
[0018]
As a result, the valve means arranged in the ink supply path from the ink cartridge to the sub tank is opened, and ink is supplied from the cartridge to the sub tank by the action of the pressurized air supplied into the cartridge. In this case, the detection level of the ink low state by the ink amount detection means is set so that the ink remains in the sub tank even when the ink is consumed by performing the cleaning operation once. It is possible to avoid the problem that the printer becomes empty and falls into a severe printing failure state.
[0019]
Therefore, a normal printing state can be ensured by setting the pressure of the pressurized air so that the ink supply amount to the sub tank covers the maximum ink discharge amount in the printing state of the recording head. In other words, it is not necessary to have a large set pressure that can immediately replenish the amount of ink consumed by the execution of the cleaning operation, thereby improving the reliability of the pressurized air supply system.
[0020]
DETAILED DESCRIPTION OF THE INVENTION
DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an ink jet recording apparatus according to the present invention will be described based on an embodiment shown in the drawings. FIG. 1 is a top view showing an example of an ink jet recording apparatus to which the present invention is applied. In FIG. 1, reference numeral 1 denotes a carriage. The carriage 1 is guided by a scanning guide member 4 via a timing belt 3 driven by a carriage motor 2, in the longitudinal direction of the paper feeding member 5, that is, in the width direction of the recording paper. It is configured to reciprocate in a certain main scanning direction. Although not shown in FIG. 1, an ink jet recording head 6 described later is mounted on the surface of the carriage 1 that faces the paper feeding member 5.
[0021]
The carriage 1 is equipped with sub tanks 7a to 7d for supplying ink to the recording head. In this embodiment, four sub-tanks 7a to 7d are provided corresponding to each ink in order to temporarily store each ink therein. The main tanks 9a to 9d as the ink cartridges loaded in the cartridge holder 8 disposed at the end of the apparatus with respect to the sub tanks 7a to 7d are connected to the respective ink supply tubes 10, 10, Each of the inks of black, yellow, magenta, and cyan is supplied through.
[0022]
On the other hand, in a non-printing area (home position) on the movement path of the carriage 1, a capping unit 11 capable of sealing the nozzle forming surface of the recording head is disposed. On the upper surface of the capping means 11, a cap member 11a formed of a flexible material such as rubber capable of sealing the nozzle forming surface of the recording head is provided. Then, when the carriage 1 moves to the home position, the capping means 11 rises following this and the nozzle forming surface of the recording head can be sealed by the cap member 11a.
[0023]
The cap member 11a functions as a lid that seals the nozzle forming surface of the recording head and prevents the nozzle openings from drying during the rest period of the recording apparatus. Further, as will be described later with reference to FIG. 2, the capping means 11 is connected to one end of a tube in a suction pump (tube pump). The cleaning operation for sucking and discharging the ink from is performed. Further, a wiping member 12 made of an elastic material such as rubber is disposed on the printing area side adjacent to the capping means 11, and the nozzle forming surface of the recording head can be wiped and cleaned as necessary. It is configured to be able to.
[0024]
Next, FIG. 2 schematically shows an ink supply system mounted on the recording apparatus shown in FIG. 1, and this ink supply system will be described with reference to FIG. 1 and 2, reference numeral 21 denotes a pressurizing pump. Pressurized air generated by the pressurizing pump 21 is supplied to a pressure regulating valve 22, and each main unit described above is connected via a pressure detector 23. The tanks 9a to 9d (represented by the reference numeral 9 in FIG. 2 as a representative and may be described simply as the reference numeral 9 in the following) may be respectively supplied.
[0025]
The pressure regulating valve 22 opens when a predetermined air pressure is applied, and acts to maintain the pressure of the pressurized air within a predetermined range by releasing a part of the pressurized air to the atmosphere. . The pressure detector 23 detects the pressure of the pressurized air, outputs an on / off electrical signal, for example, and controls a motor (not shown) that drives the pressurizing pump 21 to control the mains described later. It acts to always apply a certain range of pressurized air to the pressure chamber of the tank.
[0026]
As shown in FIG. 2, the main tank 9 has an outer case formed in an airtight state, and an ink pack 24 formed of a flexible material in which ink is sealed. Is stored. A space formed by the outer case of the main tank 9 and the ink pack 24 constitutes a pressure chamber 25, and pressurized air is supplied into the pressure chamber 25 via the pressure detector 23. It is configured. With this configuration, each ink pack 24 stored in each main tank 9a to 9d is pressurized by pressurized air, and an ink flow is generated from each main tank 9a to 9d to each sub tank 7a to 7d. Acts like
[0027]
Therefore, the ink pressurized in the main tanks 9a to 9d is supplied to the sub tanks 7a mounted on the carriage 1 via the ink supply valves 26, 26,... And the ink supply tubes 10, 10,. To 7d (represented by reference numeral 7 in FIG. 2 as a representative and may be described simply as reference numeral 7 in the following).
[0028]
A detailed description of the configuration of the sub-tank 7 shown in FIG. 2 will be described later, but the basic configuration is that a float member 31 is arranged inside, and a permanent magnet 32 is attached to a part of the float member 31. Yes. Magnetoelectric conversion elements 33 a and 33 b typified by Hall elements are attached to the substrate 34 and attached to the side wall of the sub tank 7. With this configuration, the lines of magnetic force due to the permanent magnet 32 act on the Hall elements 33a and 33b according to the floating position of the float member 31 corresponding to the amount of ink in the sub tank. Therefore, the ink amount in the sub tank can be detected by the electrical output of the hall elements 33a and 33b.
[0029]
With the above-described configuration, when the ink amount in the sub tank 7 decreases and reaches a predetermined value (ink low) due to a printing operation or the like, the position of the float member 31 housed in the sub tank moves in the direction of gravity. Accordingly, the position of the permanent magnet 32 also moves in the direction of gravity. Accordingly, the ink supply valve 26 is opened by the electrical output of the Hall elements 33a and 33b due to the movement of the permanent magnet.
[0030]
Thereby, the ink pressurized in the main tank 9 is sent into each sub tank 7 in which the ink amount is reduced. When the ink amount in the sub tank 7 reaches a sufficient amount, the valve 26 is valved based on the electrical outputs of the Hall elements 33a and 33b. By repeating such operation, the ink is intermittently replenished from the main tank to the sub-tanks, so that a substantially constant range of ink is always stored in each sub-tank.
[0031]
In this way, each ink pressurized by the air pressure in the main tank is replenished to each sub tank based on an electrical output based on the position of each float member arranged in the sub tank. Since it is configured, the ink replenishment response can be improved, and the amount of ink stored in the sub tank is appropriately managed. On the other hand, ink is supplied from each sub-tank 7 to the recording head 6 via a valve unit 35 and a tube 36 connected thereto, which will be described later. Then, based on print data given to an actuator (not shown) of the recording head 6, the ink droplets are ejected from the nozzle openings 6 a on the nozzle formation surface of the recording head 6.
[0032]
In FIG. 2, reference numeral 11 denotes the capping unit described above, and a tube 37 a having one end connected to the capping unit 11 constitutes a part of a suction pump (tube pump) 37. The other end of the tube 37 a is connected to a waste liquid tank 38, and the waste liquid sucked by the suction pump 37 is led out to the waste liquid tank 38.
[0033]
3 to 5 show an embodiment of the above-described sub tank. FIG. 3 omits a part of the configuration of the sub tank, and shows this in a perspective view seen from one side, and FIG. A perspective view seen from the direction is shown. Further, FIG. 5 is a rear view of the sub tank as viewed from the back side. 3 to 5, parts corresponding to the parts already described are denoted by the same reference numerals.
[0034]
The sub-tank 7 is formed in a substantially rectangular parallelepiped shape, and is entirely flat. The outer shell of the sub tank 7 is composed of a box-like member 41 in which a side wall 41a and a peripheral side wall 41b connected to the side wall 41a are integrally formed. A member 42 (see FIG. 4) is attached in close contact with the heat welding means, and an ink storage space 43 is formed inside the box member 41 and the film member 42.
[0035]
A support shaft 44 that protrudes from the one side wall 41 a constituting the box-shaped member 41 toward the ink storage space 43 is formed integrally with the box-shaped member 41, and the float member 31 rotates the support shaft 44. As a center of movement, the ink storage space 43 is arranged so as to be movable in the direction of gravity. In this embodiment, the support shaft 44 is disposed in the vicinity of the horizontal end of the ink storage space 43, and the float member 31 is supported by being movable about the support shaft 44. The arm member 45 is integrally formed on the movable free end side.
[0036]
As shown in FIG. 4, the permanent magnet 32 is attached to the free end side of the support arm member 45, and this permanent magnet 32 is used when the support arm member 45 is in a substantially horizontal state. The ink storage space 43 is positioned near the other end portion in the horizontal direction, that is, closest to the Hall elements 33 a and 33 b mounted on the substrate 34 attached to the side wall of the sub tank 7. .
[0037]
The Hall elements 33a and 33b are inserted into positioning recesses 41c formed on the side walls of the sub tank 7. By forming the positioning recesses 41c, the side walls of the sub tank 7 are made thinner. The movement trajectory of the permanent magnet 32 attached to the float member 31 and the distance between the hall elements 33a and 33b can be made closer.
[0038]
On the other hand, the sub tank 7 is formed with an ink supply port 46 at a lower portion in the gravity direction, that is, in the bottom of the peripheral side wall 41b in this embodiment, and the tube 10 connected to the ink supply port 46 is formed. Ink is supplied to the ink storage space 43 from the main tank 9 via the. As described above, the ink supply port 46 in the sub tank 7 is formed at the lower part in the direction of gravity, so that the ink from the main tank is supplied from the bottom of the ink storage space 43. Consideration is given so that ink bubbles do not occur in the space 43.
[0039]
Further, a plurality of rib members 47 are provided in the sub-tank 7 to reduce the degree of ink undulation in the sub-tank accompanying the movement of the carriage in a portion that avoids the movement region of the float member 31 and the support arm member 45. Is arranged. In this embodiment, the rib member 47 is integrally formed with the one side wall 41 a as a base so as to protrude from the one side wall 41 a of the box-shaped member 41 constituting the sub tank 7 toward the ink storage space 43. . The presence of the rib member 47 can reduce the degree of ink undulation in the sub-tank as described above, thereby improving the detection accuracy of the amount of ink stored in the sub-tank 7 by the Hall element. .
[0040]
In addition, an ink outlet port 48 is formed in the sub tank 7 in the vicinity of the ink supply port 46. A filter member 49 for trapping foreign matter that forms a pentagon (home base shape) is disposed so as to cover the ink outlet 48, and therefore, the ink stored in the sub tank 7 passes through the filter member 49. Thus, the ink is led to the ink outlet 48. As shown in FIG. 5, the ink led out from the ink outlet 48 is led to the groove portion 50 formed on the back surface of the side wall 41a, and is formed by the film-like member 51 that is thermally welded so as to cover the groove portion. It is configured to reach the valve unit 35 disposed at the lower bottom portion of the sub tank 7 through the ink outlet path.
[0041]
Then, an ink lead-out path (also denoted by the same reference numeral) formed by the film-like member 51 led out through the valve unit 35 to the groove 52 formed on the back surface of the side wall 41a and thermally welded so as to cover the groove. (Shown by 52) is guided to the connection port 53 of the tube 36 connected to the recording head 6.
[0042]
On the other hand, as shown in FIGS. 3 and 4, the upper half of the sub-tank 7 is formed with a conducting groove 61 that conducts to the ink storage space 43 in an inclined state. An air communication port 62 penetrating the back surface of the side wall 41 a of the sub tank 7 is formed at a high portion in the gravity direction of the sub tank 7. As shown in FIG. 5, the atmosphere communication port 62 is disposed on the back surface of the sub tank 7, and is closed by a water repellent film 63 that allows the atmosphere to pass and prevents the ink from passing.
[0043]
A meandering groove 65 is formed on the back surface of the side wall 41 a through the water repellent film 63, and the end of the meandering groove 65 communicates with a bottomed hole 66 formed in the side wall 41 a of the sub tank 7. . The meandering groove 65 and the bottomed hole 66 are covered with the film member 64 in an airtight state. Therefore, the meandering groove 65 and the film member 64 cause an air flow resistance path (reference numeral 65 is the same as the meandering groove). Is formed.
[0044]
Then, by breaking the film-like member 64 covering the bottomed hole 66 with a sharp tool or the like, the atmosphere opening 62 is communicated with the atmosphere via the air circulation resistance path 65 formed in a meandering shape. To be made. As described above, since the air communication port 62 formed in the sub tank 7 is covered with the water repellent film 63, the water repellent film 63 is accidentally turned upside down, for example. Therefore, it is possible to avoid the problem that the ink in the sub tank 7 leaks due to the presence of.
[0045]
Further, the bottomed hole 66 formed at the end of the air flow resistance path 65 is configured to be covered in an airtight state by the film member 64 in advance, so that the subtank liquid leakage (ink leakage) is completed when the subtank is completed. ) Can be checked, and when this check is completed, the film-like member 64 covering the bottomed hole 66 can be destroyed to provide the original function.
[0046]
The sub-tank 7 has a through-hole 67 formed therein, and the sub-tanks 7 are arranged in parallel by a single support shaft (not shown) that passes through the through-hole 67 and supports each sub-tank 7. The sub-tank unit is configured to be supported.
[0047]
According to the above configuration, the ink replenishment amount to each sub tank 7 per unit time has a correlation with the pressure of the pressurized air applied to the pressure chamber 25 of the main tank 9. That is, if the pressure setting value of the pressurized air is increased, the ink replenishment amount to each sub tank 7 per unit time is also increased. The pressure set value is managed by the pressure detector 23 shown in FIG. 1 and FIG. 2, and the pressure set value in this embodiment is that the amount of ink replenished to the sub tank is determined by the print head printing. It is set to an extent that covers the maximum ink discharge amount (ink discharge amount at full duty) in the state. As a result, the ink is replenished to the sub-tank without hindering the printing operation of the recording head.
[0048]
On the other hand, in the ink amount detection means by the float member in the sub tank, the ink low detection level is set so that the ink remains in the sub tank even when the ink is consumed by executing the cleaning operation once. By setting the detection level of the incrow in this way, it is possible to prevent the ink in the sub tank from becoming empty even if the cleaning operation is performed immediately before the ink amount detection unit detects ink low, for example. it can.
[0049]
As a method for setting the ink-low detection level in realizing this, the concept as shown in FIG. 6 can be adopted. FIGS. 6A and 6B schematically show the state of the sub tank in the ink-low state. First, FIG. 6A shows a state in which the ink capacity in the sub-tank corresponding to a predetermined value (ink low) detected by the ink amount detecting means is set to be equal to or larger than the ink consumption by one cleaning operation. Yes. In this case, the residual ink amount in the sub tank at the ink low detection level is shown as (A). If the ink consumption by one cleaning operation is (B), and the ink low level is set so that A ≧ B, the cleaning operation is performed just before the ink amount detection means detects the ink low. Even if is executed, it is possible to prevent the ink in the sub tank from becoming empty.
[0050]
Next, FIG. 6B shows that the ink capacity in the sub-tank corresponding to the predetermined value (ink low) detected by the ink amount detecting means is replenished into the sub-tank during the cleaning operation from the ink consumption by one cleaning operation. This shows a state where the ink amount is set to be equal to or larger than the amount obtained by subtracting the ink amount to be subtracted. In this case, the residual ink amount in the sub tank at the ink low detection level is indicated as (A ′). The ink consumption by one cleaning operation is (B). However, when the cleaning operation is performed and the ink amount detection means detects ink low, the ink supply valve 26 is opened, so that the ink amount shown as (C) during the cleaning operation is in the sub tank. Will be replenished.
[0051]
Therefore, if the ink low level is set so as to satisfy the relationship (A ′ + C) ≧ B, even if the cleaning operation is performed just before the ink amount detecting means detects the ink low, the ink in the sub tank is empty. It can prevent becoming a state. In other words, the relationship is A ′ ≧ (BC) as described above. As a result, the ink low level detected by the ink amount detection means can be set to a lower level than in the case shown in FIG. 6A, and each sub tank capacity mounted on the carriage can be reduced in size. It is also possible to design.
[0052]
【The invention's effect】
As apparent from the above description, the ink jet recording apparatus according to the present invention can replenish necessary and sufficient ink from the ink cartridge to the sub tank by the action of the pressurized air. And since the set pressure of the pressurized air with respect to an ink cartridge can be reduced, the reliability of each part to which pressurized air is applied can be improved. In addition, even when the cleaning operation is executed, it is possible to prevent the ink in the sub tank from becoming empty, so that it is possible to prevent air bubbles from entering the recording head and causing serious printing failures. Is possible.
[Brief description of the drawings]
FIG. 1 is a plan view showing an overall configuration of an ink jet recording apparatus to which the present invention is applied.
FIG. 2 is a schematic diagram illustrating a configuration of an ink supply system from an ink cartridge to a recording head.
FIG. 3 is a perspective view of a state in which a part of the configuration of the sub-tank is omitted and viewed from one surface direction.
FIG. 4 is a perspective view of the sub-tank as seen from one direction.
FIG. 5 is a rear view of the sub-tank as seen from the back side.
FIG. 6 is a schematic diagram showing a preferable ink amount detection level when an ink low state is detected by an ink amount detection unit arranged in a sub tank.
[Explanation of symbols]
1 Carriage
6 Recording head
7 (7a, 7b, 7c, 7d) Sub tank
8 Cartridge holder
9 (9a, 9b, 9c, 9d) Main tank (ink cartridge)
10 Ink supply tube (ink supply path)
11 Capping means
21 Pressure pump
22 Pressure regulating valve
23 Pressure detector
24 ink pack
25 Pressure chamber
26 Ink supply valve
31 Float member (ink amount detection means)
32 Permanent magnet
33a, 33b Hall element (output generating means)
37 Suction pump
38 Waste liquid tank
43 Ink storage space

Claims (8)

A recording head mounted on a carriage and reciprocatingly moved in the width direction of the recording paper, and mounted on the carriage together with the recording head, receiving ink supply from an ink cartridge through an ink supply path, and supplying ink to the recording head An ink jet recording apparatus configured to supply ink from the ink cartridge to the sub tank by air pressure by supplying pressurized air to the ink cartridge;
When the ink amount detecting means detects that the amount of ink stored in the sub tank is equal to or less than a predetermined value, ink is replenished from the ink cartridge to the sub tank via the ink replenishment path. At the same time, ink is supplied from the ink cartridge to the sub tank via the ink supply path even when the ink amount detecting means detects that the amount of ink stored in the sub tank has become a predetermined value or less during the cleaning operation. The ink volume in the sub tank corresponding to the predetermined value detected by the ink amount detecting means is configured so that the ink amount replenished in the sub tank during the cleaning operation from the ink consumption by one cleaning operation. above amount minus and the cleaning operation of the once Is set to less than the consumption of that ink, and ink supply amount to the sub-tank through the ink supply path, the pressure of the pressurized air so as to cover the maximum amount of ink discharged in the printing state of the recording head An ink jet recording apparatus that is set.   The ink amount detection means includes a float member that floats by ink stored in the sub tank, and an output generation means that generates an electrical output according to the float position of the float member according to the ink amount in the sub tank. The ink jet recording apparatus according to claim 1.   3. The output generating means includes a permanent magnet disposed on a float member and a magnetoelectric conversion element that generates an electrical output in accordance with a magnetic dose by the permanent magnet according to a floating position of the float member. The ink jet recording apparatus described.   Valve means disposed in the ink supply path and controlled to open / close in response to electrical output from the output generating means is provided, and ink is intermittently supplied from the ink cartridge to the sub tank by the opening / closing operation of the valve means. 4. The ink jet recording apparatus according to claim 2, wherein the ink jet recording apparatus is configured to be replenished.   The ink cartridge is composed of an ink pack formed of a flexible material in which ink is sealed, and a cartridge case formed in an airtight state containing the ink pack. 5. An ink jet recording apparatus according to claim 1, wherein a pressure pump for supplying pressurized air is disposed in a pressure chamber formed between the cartridge case and the ink pack.   The ink jet recording apparatus according to claim 1, wherein an ink supply path from the ink cartridge to the sub tank is configured by a flexible ink supply tube.   The ink jet recording apparatus according to claim 1, wherein the air pressure of the pressurized air is managed by a pressure detector that is driven and displaced by the air pressure.   8. The ink jet recording apparatus according to claim 7, wherein the pressure detector includes a diaphragm that is displaced by receiving pressurized air, and an output generation unit that generates a control signal based on the displacement of the diaphragm at a set pressure. .

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