JP2831678B2 - Ink tank integrated recording head and ink jet recording apparatus using the head - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink jet recording head integrated with an ink tank and an ink jet recording apparatus using the same.

[Prior Art] Conventionally, an ink jet recording apparatus has a cartridge type ink tank that stores a predetermined amount of ink separately from a recording head, and replaces the ink tank when the remaining amount is low or low. In general, ink is supplied again. However, when the recording head body that performs ink discharge is inexpensive (in the case of using an electrothermal transducer as an energy generating element for ink discharge,
The manufacturing cost can be reduced because the ejection ports can be mass-produced in the same manufacturing process as the semiconductor, so that the manufacturing cost can be reduced.) Various types that can be attached to and detached from have been proposed.

In the latter case, by integrating the ink tank and the printhead main body, the printhead can be reliably and automatically updated for each predetermined print amount corresponding to the ink capacity, so that good print quality is always maintained. It becomes possible.
Also, even if a problem such as degraded recording quality occurs in the recording head body and it cannot be recovered, the recording head, which can be called the heart of the device, can be easily replaced, making it impossible to operate as a recording device. (Downtime) can be significantly reduced.
Further, problems that may occur when the recording head main body and the ink tank are separate bodies, such as mixing of foreign matter that may occur during ink supply, air bubbles in the ink supply path between the ink tank and the recording head main body, and the like. The problem such as mixing of ash is less likely to occur.

The ink tank used for such a cartridge includes:
Particularly, in the case of an ink tank used for a cartridge mountable on a so-called serial printer type ink jet recording apparatus which performs recording while scanning a recording head in a predetermined direction on a recording medium, an absorber is provided and ink The idea of impregnating is adopted. This is not only to stabilize the pressure generated at the discharge port due to the head difference, but also to prevent gas dissolution and ink leakage caused by ink swaying during scanning, scanning reversal, transportation or other impact effects. It is valid.

[Problems to be Solved by the Invention] However, in the recording head integrated with the ink tank, the cost of the main body of the ink jet recording head is included in the running cost in addition to the ink, and therefore, compared to the cartridge using only the ink. There is a disadvantage that running costs are relatively high.

In order to reduce the running cost, it is conceivable to increase the ink capacity.However, the size of the cartridge is increased. Therefore, as the size of the cartridge increases, the moving space of the cartridge also increases, and the size of the main body of the recording apparatus cannot be avoided. Further, in this case, it is difficult to repeatedly move a large and heavy cartridge with high precision, and therefore, it is conceivable that the recording quality may be degraded.

Therefore, in this case, a method has been proposed in which the head body portion and the ink tank portion are divided and mounted on separate moving means, and these are communicated by a tube or the like so that they are simultaneously scanned. In this case, it is not possible to take advantage of the feature of the cartridge of the head, which can avoid the danger of foreign matter entering during ink replenishment.

In particular, in a recording head in which an ink tank containing a built-in absorber impregnated with ink is integrated, the volume of the absorber itself occupies several tens of percent of the volume in the ink tank, and the final amount of the initial ink amount The amount of ink that cannot be removed from the absorber
% Or more, the net usable amount of the ink with respect to the internal volume is low, and the above problem becomes significant.

In addition, impregnating the ink absorber can stabilize the pressure at the discharge port portion due to the head difference considerably compared to a case where the ink is simply stored and having a free surface. Since the ink leakage and the ejection direction, or “distortion” due to the wetting of the ejection port forming surface, and the fluctuation of the ejection amount, etc., should be strictly stabilized. However, when an absorber is provided, the ink is drawn in the direction of the absorber by the capillary force. Therefore, in the conventional configuration in which the absorber is filled in the ink tank, the power fluctuates significantly depending on the amount of remaining ink, and therefore, There is a limit in stabilizing the pressure at the discharge port.

SUMMARY OF THE INVENTION It is an object of the present invention to reduce the running cost or reduce the scanning space capacity by increasing the ink storage capacity with respect to the tank internal volume, and to suppress fluctuations in the pressure of the discharge port to stably obtain a good image. Is to be able to do it.

[Means for Solving the Problems] The first embodiment of the present invention integrally includes an ejection unit that ejects ink to perform recording, and an ink tank that stores ink to be supplied to the ejection unit. An ink tank-integrated recording head, wherein the ink tank has an air communication port and an absorber for holding ink, and a supply unit that supplies the ink held in the absorber to the ejection unit. A storage unit for storing the ink to be supplied to the supply unit independently of the supply unit; and a supply unit configured to communicate with the storage unit and the supply unit to supply the ink stored in the storage unit to the supply unit. And communication means for opening and closing the communication path.

In this case, the apparatus may further include a remaining amount detecting unit that detects a remaining amount of the ink held in the absorber.
Further, the communication path may communicate with a lower part of the supply unit. Further, the discharge section may include discharge energy generating means having an electrothermal converter. In this case, the electrothermal transducer may generate thermal energy for discharge in response to energization.

According to a second aspect of the present invention, there is provided an ink jet recording apparatus comprising: means for detachably supporting the above-described ink tank integrated recording head; and driving means for driving the opening / closing means. It is in.

In this case, when the remaining amount of ink detected by the above-described remaining amount detection unit is less than a predetermined amount, the driving unit may drive the opening / closing unit to open the communication path.

(Operation)

According to the present invention, the supply section and the storage section are independent in the ink tank, and the volume of the storage section is increased by making the volume of the supply section relatively smaller than the volume of the storage section. The net storage capacity of the possible ink is increased.

Also, when the remaining amount of ink held in the absorber becomes small and it becomes necessary to replenish the ink in the supply unit,
Operate the opening / closing means to open the communication path, replenish the ink stored in the storage section to the supply section from the communication path, impregnate the ink in the absorber in this supply section, and thereby adjust the ink pressure in the ejection section to an appropriate level. To maintain the proper range.

Embodiments Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. Prior to this, the structure of a portion to which the present invention is applied will be described below, and this ink tank integrated recording head cartridge will be described. Instead, an ink tank-integrated recording head cartridge according to the present invention, for example, having a structure shown in FIG. 6 may be employed.

FIG. 1 is a sectional view of an ink jet recording apparatus including such an ink tank integrated recording head which is the object of the present invention. Here, reference numeral 1 denotes a recording head chip which is a main body of the ink jet recording head, and ejects ink in accordance with a recording signal while moving to face the recording medium 20.
An ink tank 2 for storing a predetermined amount of ink is provided with a supply unit 6 having an absorber 4 and an ink amount detecting electrode 5 and a recording head chip 1 by a partition plate 3 having a communicating portion at the top and functioning as a replenishing means. The head is exchanged according to the consumption of a predetermined amount of ink. Supply unit 6 of ink tank 2
Is connected to the head chip 1 via a porous filter 7 having a pore size that does not easily allow air bubbles to pass therethrough, and the upper part thereof is filled with an absorbent body 4 having pores. Holds the ink. At the top of the ink tank 2, a fine air communication hole 8 is provided via a hydrophobic open-cell body 9, so that the ink held by the absorber according to the consumption of ink from the head chip portion can be used. Thus, ink is supplied from the supply unit 6 to the recording head chip 1 without generating bubbles.

The liquid path array 10 of the print head chip 1 and the supply unit 4 of the ink tank 2 respectively include a discharge energy generating element such as an electrothermal converter that generates energy for discharging ink in accordance with a print signal. A pin-shaped ink remaining amount detecting electrode 5 inserted into the absorber 4 is formed, and an electrode for making an electrical connection to these electrodes is provided in an electrode row.
It is organized in 11 forms. Reference numeral 15 denotes a liquid chamber which receives ink from the absorber 4 and supplies it to each liquid path.

The cartridge is mainly handled with the ink tank 2 side.
In the figure, the operation is performed in the directions of the arrows A and B. At the time of mounting, the cartridge lever 12 holding the tank 2 is pushed in the direction (D direction) opposite to the urging direction (C direction), dropped into the carriage from almost above, and each has an inclined surface. By engaging the engaging portion 14 of the cartridge and the receiving portion 13 of the carriage, the electrode array 11 and the flexible cable 15 connected to the main body control portion are pressed against each other. After the cartridge is inserted, the cartridge lever 12 is slowly operated in the direction C to urge the cartridge downward, and is fixedly supported on the carriage 13. Further, the cartridge can be taken out only by opening the cartridge lever 12 and pulling the cartridge upward, so that the cartridge can be easily attached and detached.

At the time of recording by the recording apparatus according to this reference example, a carriage shaft is moved with respect to the recording medium 20 conveyed in the F direction on the guide 18 by the feed roller pair 16 and the discharge roller pair 19.
The carriage scan is performed while the recording medium 20 is pressed onto the guide 18 by the paper holding rail 17 via the rollers 21 of the carriage 23 scanned along 22.

FIG. 2 shows a plan view of the device according to this reference example. The carriage 23 is fixed to a drive wire 26 wound around a scanning drum 27 that rotates in synchronization with a recording signal. The carriage 23 reciprocates between pulleys 28 and 29 to scan in the direction of arrow G. Reference numeral 31 denotes a motor for rotating the carriage 23 in the direction E in FIG. 1, and a gear (carriage gear) 25 which can be engaged with a gear (carriage gear) 25 provided on a side surface of the carriage 23 around the carriage shaft 22. (A carriage rotating gear) 30 is provided.

When the amount of ink in the absorber 4 decreases due to consumption of the small but conductive ink, the electrical resistance of the absorber 4 increases as shown in FIG. It can be detected that the detected value has changed and the amount of ink in the absorber 4 has become less than the predetermined amount. At this time, the carriage 23 is moved to a position where the carriage gear 25 and the carriage rotating gear 30 mesh with each other, and an ink supply operation to the absorber 4 is performed.

The operation will be described with reference to FIG. When the carriage rotation motor 31 rotates, the carriage 23 rotates around the carriage shaft 22 in the E direction and assumes a posture as shown in FIG. In this position, the ink tank 2 serving as an ink storage
Is supplied from the upper part of the partition plate 3 to the supply part 6,
The absorber 4 again holds sufficient ink. Thereafter, the motor 31 is reversed to return the carriage 23 or the cartridge to the original position.

In addition, it is conceivable that an amount of ink exceeding the holding power of the absorber flows into the supply unit during such ink supply. In such a case, as shown in FIG. 5, a suction means composed of a suction cap 32, a suction hole 33 and a suction pump 34 is used, and depending on the case of the suction cap 32, an appropriate amount of suction is sucked from the nozzle row 10 to discharge. The outlet can be kept at a proper head.

By the way, in the absorber 4 used in this reference example, when the ink amount exceeds about 70% of the volume, the head pressure of the discharge port portion exceeds an appropriate negative range (−20 to −40 mmaqu), and Leakage from the outlet and wetting of the ejection port forming surface are apt to occur, and conversely, ejection becomes unstable with an ink amount of 20% or less. However, comparing the conventional configuration and the configuration of this reference example with respect to the ink capacity, the configuration of this reference example allows more ink to be used effectively in the same volume than the conventional configuration. That is, in the conventional configuration, the absorber is filled in the entire area inside, so that it alone wastes 30% of the internal volume, and in addition, the amount of ink that was initially charged cannot be extracted from the inner absorber. Over 10%. On the other hand, in this reference example, since the absorber is provided in a part of the cartridge, the ratio of the absorber to the volume in the cartridge is reduced, so that the effective use amount of the ink can be increased.

In this reference example, as means for performing a predetermined operation for rotating the carriage 23 or the cartridge, not only the means using the motor 31 as described above but also various configurations can be adopted. For example, a member that engages with the carriage 23 and guides the carriage 23 while rotating it in the direction E is provided at a predetermined position. When the remaining amount detection electrode detects less than a predetermined amount, the carriage is moved along the member. 23 may be moved. Alternatively, the operator may remove the cartridge from the carriage 23 and shake it to supply ink.

In contrast to the above-described ink tank integrated head, the ink tank integrated head according to the present invention described below, that is, the ink communication path between the ink tank unit and the ink supply unit is provided in the cartridge itself without displacing the cartridge. A means for enabling opening / closing is provided, and ink is supplied at the time of opening.

FIG. 6 shows an embodiment of such an ink tank integrated type recording head cartridge according to the present invention. In the drawing, unlike the above embodiment in which the discharge direction is vertically downward,
The direction in which the ejection direction is the horizontal direction is shown. However,
The same parts as those in the configuration shown in FIG.

Here, reference numeral 117 denotes a valve element as a replenishing means for opening / closing a communication part provided in the partition part 3 between the ink tank 2 and the absorber 4, and is constituted by a magnetic substance or a permanent magnet. Reference numeral 18 denotes a spring that presses the valve body 117 in the closing direction (left direction in the figure). Reference numeral 19 denotes a communication portion for communicating the absorber 4 with the atmosphere. Numeral 127 denotes a valve driving member provided on the cartridge or the carriage and slidable in the direction shown by the arrow in connection with a plunger (not shown) provided on the main body side, and is constituted by a permanent magnet or an electromagnet. .

In this example, when it is detected that the remaining amount of ink in the absorber 4 has become less than the predetermined amount between the remaining amount detecting electrodes 5, the plunger is driven to move the valve body driving member 127 rightward in the drawing. When moved, the valve body 117 also moves in the same direction against the urging force of the spring 18 due to the magnetic force. Then, the communication path between the ink tank 2 and the absorber 4 is opened, and ink is supplied to the absorber 4. Thereafter, when the valve body driving member 127 is moved leftward in the drawing, the valve body 117 also moves to the closed position.
With the urging force of 8, the movement is quickly performed, and the closed state is ensured.

Note that the valve body 117 and the valve body driving member 127 may have any configuration as long as the communication path for replenishing ink is opened / closed by the magnetic force as described above. May not be accompanied. In addition, even if the recording head is not magnetically driven, the ink may be supplied by removing the recording head and operating a lever or the like provided integrally with the valve body and protruding to the outside. it can.

In any case, according to the present embodiment, ink supply is not performed by rotating the carriage or the like as in the reference example shown in FIG. Therefore, ink supply can be performed by the recording head itself, so that a separate ink supply operation can be performed even when a plurality of recording heads are provided on the carriage. Further, since the ink is supplied from the lower side, air bubbles are less likely to be mixed in the lower part of the absorber 4 where the supply port to the head is provided. Furthermore, in the above configuration, since the ink supply operation is performed promptly and without the displacement of the print head, the ink supply operation can be performed not only during the print operation but also at a short interval depending on the remaining amount detection level. Thereby, the head of the discharge port can be maintained uniformly.

Next, the relationship between the remaining amount of ink (the amount of ink held by the absorber) and the pressure (water head pressure) applied to the ejection port in the above-described embodiment will be considered.

FIG. 7 shows the relationship, in which the curve a shows the case where the absorbing power by the absorber 4 is small, and the curve b shows the case where it is large. The “maximum holding amount of the absorber” is a state immediately after the ink is replenished from the absorber 4 to the extent that the ink overflows.

Here, it is desirable that the pressure in the vicinity of the discharge port is maintained at a predetermined range of negative pressure. If this is positive, ink leaks from the discharge port, or the discharge port forming surface is wetted due to the leakage or defective ink drawing operation after the discharge operation, and if the negative pressure exceeds a predetermined value, the discharge operation becomes smooth. This is because it becomes difficult to perform ink refilling near the ejection openings after ejection, and in any case, it adversely affects the ejection characteristics and the ejection amount and disturbs the image quality. Become.

FIG. 8 shows the relationship between the water head pressure of the discharge port and the ink discharge amount. In order to obtain a good quality image by making the recording dot diameter uniform, it is strongly desirable that the ink ejection amount is stable, and since the water ejection pressure is involved in the ink ejection amount, the ink ejection amount is almost constant. Before the head pressure suddenly decreases beyond a certain range, the electrode 5 for detecting the remaining amount of the absorber 4
It is desirable that the replenishing operation is performed based on the output of the above.

Referring again to FIG. 7, the pressure at the discharge port portion is determined by the capillary force of the liquid path, the absorbing power of the absorber 4, and the like. In particular, in the configuration as shown in Fig. 1 in which the discharge direction is vertically downward, the absorption port is large and the discharge port portion quickly becomes negative pressure in consideration of the influence of the pressure due to the positional relationship between the absorber portion and the discharge port surface. It is desirable to select an absorber that exhibits the curve b as follows. On the other hand, the absorber shown by the curve a is disadvantageous because the amount of ink stored in the absorber portion is small and the ink ratio to the entire cartridge is small. On the other hand, in the configuration as shown in FIG. 6 in which the ink is ejected in the horizontal direction, a negative pressure can be easily obtained even if the remaining amount of ink is large because of the positional relationship between the absorber portion and the ejection port surface. It may have a small absorbing power.

In the curve b, the fluctuation amount of the head pressure is large.
As shown in the figure, the remaining amount may be detected before the amount of ink discharged drops sharply. Further, for a head chip or the like having a large ink ejection energy, the ejection characteristics of which are not easily degraded even with slight wetting of the ejection port, as long as the ink meniscus near the ejection port is not broken and no leakage occurs, The head pressure at that time may be positive.

According to the present invention, the ink tank is divided into a supply section having an absorber inside the ink tank and supplying the ink to the head chip, and a storage section storing the ink, and the ink supply section appropriately supplies ink to the supply section side. Of course, as long as the configuration is possible, various configurations can be adopted without being limited to the above-described embodiment.

For example, a partition wall that completely separates the supply unit side and the storage unit side and partially forms a manually destructible part is provided,
When the supply section becomes full, the section is destroyed to obtain a communication state, whereby ink supply can be performed only once, and a plurality of such storage sections or partition walls are provided. Thus, a plurality of ink replenishments can be performed.

[Effects of the Invention] According to the present invention, a supply unit provided with an absorber for holding ink supplied to a discharge unit, and a storage unit for storing ink to be supplied to the supply unit are provided independently. An opening / closing means for opening and closing the communication path is provided in a communication path for replenishing the supply section with the ink stored in the storage section in communication with the storage section and the supply section. It is possible to increase the amount, prevent the scanning space from becoming large, or reduce the running cost, and suppress the pressure fluctuation at the discharge port to stably obtain a good image.

[Brief description of the drawings]

FIG. 1 is a side sectional view of an ink jet recording apparatus including an ink tank integrated recording head according to the present invention, FIG. 2 is a plan view of the recording apparatus, and FIG. FIG. 4 is an explanatory diagram for explaining the operation of this reference example, FIG. 5 is a schematic diagram showing a configuration example of a suction unit applicable to the present invention, and FIG. FIG. 7 is a side sectional view of an ink-tank integrated recording head according to one embodiment, FIG. 7 is a diagram for explaining the relationship between the remaining amount of ink and the pressure of the discharge port, and FIG. FIG. 3 is a diagram for explaining a relationship with an ink ejection amount. DESCRIPTION OF SYMBOLS 1 ... Head chip, 2 ... Ink tank part, 3 ... Partition plate, 4 ... Absorber, 5 ... Remaining amount detection electrode, 6 ... Supply part, 8 ... Atmospheric communication hole, 10 ... Liquid line array, 12: Cartridge lever, 16, 19: Roller pair, 20: Recording medium, 23: Carriage, 31: Carriage rotating gear, 34: Suction pump, 117: Valve, 127 ... ... Valve drive member.

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Norifumi Koitabashi 3-30-2 Shimomaruko, Ota-ku, Tokyo Inside Canon Inc. (56) References JP-A-61-22952 (JP, A) JP-A Sho 63-41147 (JP, A) JP-A-63-303749 (JP, A) JP-A-63-87088 (JP, U) JP-A-57-16385 (JP, U) (58) Fields investigated (Int. Cl. ⁶ , DB name) B41J 2/175

Claims (7)

(57) [Claims] An ink tank-integrated recording head integrally comprising an ejection section for ejecting ink to perform recording and an ink tank containing ink to be supplied to the ejection section, wherein the ink tank is provided. Has an air communication port and an absorber for holding ink, a supply unit that supplies the ink held by the absorber to the ejection unit, and a supply unit that supplies ink supplemented to the supply unit. An accommodating portion for independently storing the ink; a communication passage communicating with the accommodating portion and the supply portion for replenishing the ink stored in the accommodating portion to the supply portion; and an opening and closing capable of opening and closing the communication passage. And an ink tank integrated type recording head. 2. A recording head integrated with an ink tank according to claim 1, further comprising a remaining amount detecting means for detecting a remaining amount of ink held in said absorber. 3. The ink tank integrated recording head according to claim 1, wherein said communication path communicates with a lower portion of said supply section. 4. An ink tank-integrated recording head according to claim 1, wherein said discharge section includes discharge energy generating means having an electrothermal converter. 5. An electrothermal converter according to claim 4, wherein said electrothermal converter generates heat energy for discharge in accordance with energization.
2. The recording head integrated with a recording head according to item 1. 6. An ink jet recording apparatus comprising: means for detachably supporting the ink tank integrated recording head according to claim 1; and driving means for driving said opening / closing means. 7. When the remaining amount of ink detected by the remaining amount detecting means according to claim 2 is less than a predetermined amount, the driving means drives the opening / closing means to open the communication path. The ink jet recording apparatus according to claim 6, wherein: