JPH02198866A - Ink-jet recorder - Google Patents

Abstract

PURPOSE:To stabilize the discharge characteristics of a recording liquid, and to supply the recording liquid by installing a recording-liquid supply mechanism supplying a first recording-liquid housing member with the recording liquid at a specified time from a second recording-liquid housing member not loaded onto a carriage. CONSTITUTION:A pin electrode 111 is used as one of electrodes for detecting residue in an absorber and a mesh electrode 116 mounted on the connecting section head side as the other, and the mesh electrode is fixed so as to cover the outlet of ink, and has a bubble filter effect and functions as a bubble mixing preventive effect in combination. The second ink tank 23 of a feeder is set up at a position higher than a first ink tank and connected to the first ink tank by a connecting pipe 26, and a mechanical valve gear 24 is fitted on its midway of the connecting pipe 26, and receives electric signals from the electrodes for detecting residue and is operated. The mechanical valve gear 24 has a mechanism sealing and opening the connecting pipe 26 by the revolution of a cam 27, and the operation of the cam by the signals of the electrodes is set so that water head pressure is kept within an approximately fixed range at all times.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to an inkjet recording device.

[Prior Art] FIG. 6 shows a first recording liquid storage member having a recording liquid absorber impregnated with a conventional recording liquid, and a system for receiving recording liquid from the storage member and applying it to a recording medium. FIG. 7(a) shows a main body view of an inkjet recording apparatus that is mounted on a carriage in a connected state with a discharge unit that performs recording by discharging discharge, and performs recording while moving the carriage relative to the recording medium. ) and (b) respectively show a perspective view and a sectional view of the ink tank/head integrated cartridge.

Here, 100 is a recording chip, and a discharge unit 10
2, a supply tank section 104, etc. Discharge part 102
is an ejection port 102A formed on the surface facing the recording medium;
It has a liquid path extending inward, a discharge energy generating element such as an electrothermal converter disposed in each liquid path, and a common liquid chamber communicating with each liquid path. Further, the supply tank section 104 functions as a sub-tank that receives ink supply from the ink tank 110 side and guides the ink to the common liquid chamber in the discharge section 102 .

An ink absorber 112 is disposed within the ink tank 110 and is impregnated with ink, and can be formed using a porous material, fiber, or the like. 114 is a lid member of the ink tank 110.

Using the inkjet recording head configured as described above, it is possible to construct an inkjet printer as shown in FIG. 6, that is, an inkjet printer using a disposable cartridge type recording head.

In addition, 14 in FIG. 6 corresponds to FIG. 7 (a) and (b).
The recording head 14 is in the form of a cartridge as shown in FIG. 1, and the recording head 14 is fixed on a carriage 15 by a pressing member 41, and is capable of reciprocating in the longitudinal direction along a shaft 21. Also, carriage 1
For example, the positioning for the RAD chip 100 to record
This can be done using a hole provided in the carriage 15 and a dowel provided on the carriage 15 side. Furthermore, the electrical connection is made to the discharge part 102.
Carriage 1 is connected to the connection pad provided on the wiring board for
All you have to do is connect the connectors on 5.

The ink ejected by the recording head reaches the recording medium 18 whose recording surface is regulated by the platen 19 at a slight interval from the recording head, and forms an image on the recording medium 18.

An ejection signal corresponding to image data is supplied to the recording head from an appropriate data supply source via a cable 16 and a terminal connected thereto. One or more cartridges 14 (two in the figure) can be provided depending on the ink color used.

Further, in FIG. 6, 17 is a carriage motor for scanning the carriage 15 along the shaft 21;
2 is a wire that transmits the driving force of the motor 17 to the carriage 15. Further, 20 is a feed motor coupled to the platen roller 19 for conveying the recording medium 18.

With the above-mentioned configuration, the disposable inkjet recording device improves reliability problems (bubbles, etc.) in the so-called permanent head type inkjet recording device, in which the permanent recording head and ink tank are connected by a connecting means such as a tube. An inkjet recording device (disposable head type inkjet printer) was constructed using a type of ink tank integrated cartridge.

[Problems to be Solved by the Invention] However, such conventional disposable head inkjet printers have the following three major problems.

1. Increasing the capacity of the ink tank to reduce running costs increases the volume of the ink tank on the carriage, making the printer larger and leading to increased costs. In addition, the load on the carriage drive motor increases due to the increased weight of ink, so a motor capable of outputting high torque is required, which increases the cost of the motor.

That is, if the capacity of the ink tank is increased in order to reduce running costs, there is a problem in that the cost of the main body increases significantly.

2. Also, in order to reduce running costs, increasing the ink absorption capacity of the ink absorber does not make the printer larger, and only increases the cost of the carriage drive motor as described above.However, the ink absorption capacity of the ink absorber The larger the capacity, the greater the change in water head pressure due to changes in the amount of remaining ink, and the greater the effect that the ejection characteristics change depending on the amount of remaining ink, which caused the problem that stable printing quality could not be maintained. . This change in ejection characteristics due to a change in the remaining amount of ink can be explained as follows.

When an ink tank containing an ink absorber is connected to a recording head, negative pressure is applied to the ink in the head due to capillary absorption in the absorber, and this negative pressure and pressure due to capillary absorption in the ink flow path are applied to the ink in the head. Since a meniscus is formed by the balance of the ink, the amount of ink remaining changes. In other words, when the volume of the absorber with ink absorption capacity changes, the negative pressure changes and the water head pressure changes. Figure 8 shows the relationship between the remaining ink amount and the water head pressure. In Figure 0, it can be seen that the head pressure decreases as the pressure increases.
b is a curve obtained when an absorber with higher absorbency is used than in a, and it can be seen that the higher the absorbency, the greater the change in water head pressure.

FIG. 9 shows the relationship between water head pressure and ink ejection amount.

As the water head pressure decreases, the amount of ink ejected gradually decreases, and as the water head pressure further decreases, it rapidly decreases and finally stops being ejected.This is because as the water head pressure decreases, Since the negative pressure increases, the force that pulls the ink toward the ink tank increases, and the ejection pressure decreases. Therefore, when the same ejection power is applied to the head, the amount of ink ejected decreases. Furthermore, as the water head pressure decreases, the capillary absorption force of the ink nozzle and the negative pressure become equal to each other, so it becomes difficult for ink to flow into the ink nozzle after ink is ejected, and the ink paste and fill time becomes longer. Because the drive frequency does not allow the refill to be completed in time, the amount of ink ejected rapidly decreases, and eventually no ink is ejected even though there is some remaining ink. Figure 1O shows the relationship between water head pressure and appropriate refill frequency.

For this reason, in an inkjet recording apparatus in which an ink tank containing an ink absorber and a recording head are connected to each other, the amount of ink ejected may vary depending on the amount of ink remaining in the ink tank.

3.Also, a so-called bit-in type permanent head type inkjet recording device is known, in which the ink tank and the recording head are separated and the ink is replenished from the ink tank to the recording head at a predetermined time. The practicality was low due to the inclusion of bubbles, etc.

In view of the above-mentioned conventional problems, the present invention provides an inkjet recording apparatus in which the ejection characteristics of the recording liquid are stable and the recording liquid can be replenished.

[Means for Solving the Problems] According to the present invention, a first recording liquid absorbent body, which includes a recording liquid absorbent body impregnated with a recording liquid, and has a residual amount detection means for the recording liquid inside the absorbent body.
A recording liquid storage member is mounted on a carriage in a connected state, and a discharge section that receives recording liquid from the storage member and performs recording by discharging the recording liquid onto a recording medium is mounted on a carriage. In an inkjet recording apparatus that performs recording while moving a recording medium relative to the recording medium, replenishing recording liquid to a first recording liquid storage member at a predetermined time from a second recording liquid storage member that is not mounted on a carriage. By providing a recording liquid replenishment mechanism, unlike conventional disposable type ink tank-integrated cartridges, it is possible to increase the size of the cartridge, increase the absorbency of the recording liquid absorber, increase the size of the main body, increase costs, and increase the carriage drive motor torque. Since it is possible to easily perform a printing operation continuously without any interference, and the ejection characteristics of the recording liquid can also be stabilized, a highly reliable inkjet recording apparatus can be obtained.

The inkjet recording apparatus of the present invention includes a first recording liquid storage member (hereinafter referred to as a first ink tank) and a recording liquid replenishment mechanism (hereinafter referred to as an ink replenishment mechanism) that supplies recording liquid (hereinafter referred to as ink) to the first recording liquid storage member (hereinafter referred to as a first ink tank). (abbreviation) is provided. The replenishment mechanism basically includes a first ink tank, an ink replenishment hole, and a second ink tank.
The ink supply hole is provided on the first ink tank mounted on the carriage, and the ink supply hole is not mounted on the carriage. It is connected to the second ink tank and has a removable shape. That is, the ink to be replenished is supplied from the second ink tank into the first ink tank through the ink supply hole.

Although the second ink tank is not mounted on the carriage, it does not need to be incorporated into the main body of the inkjet recording apparatus, and may be a stand-alone container that can be handled independently, or may be incorporated into the main body of the apparatus.

The ink supply hole only needs to have a shape and structure that can effectively supply ink from the second ink tank to the ink absorber in the first ink tank, and is usually placed on the top surface of the first ink tank, that is, by gravity. It is only necessary to provide the hole at a position where the ink does not leak, and the hole may be simply a hole, or a pleat may be provided to prevent the hole from leaking. The second ink tank has a connecting tube that can be connected to the ink supply hole, and the connecting tube is normally inserted into the first ink tank through the ink supply hole.

In the present invention, the remaining amount detecting means provided in the ink absorber may basically be capable of detecting the remaining amount based on resistance between electrodes, and may be composed of, for example, a set of bottle electrodes. The electrodes can be installed anywhere as long as the remaining amount can be best detected, and one electrode can be placed inside the connecting part in the first ink tank on the head side (where ink is ejected from the ink absorber to the RAD chip for recording). mouth)
If we use a mesh electrode to cover the area,
This is preferable because it also serves as a filter to prevent bubbles from entering when ink is supplied.

The detection means not only displays the replenishment time, but also displays the full point during supply.As a zero display means, it converts into a light signal or a sound signal and outputs it.
It can be recognized by visual inspection, etc. Furthermore, an automatically operating valve is installed in the connecting pipe from the second ink tank,
It is also possible to electrically connect the detection means and the valve, send a signal from the detection means directly to the valve, and automatically replenish ink (automatic ink replenishment mechanism).

The timing for supplying ink to the first ink tank is when the ink level has decreased to the point where refilling can be performed appropriately, but when the automatic ink replenishment mechanism is used, the ink head pressure in the ink absorber is It is also possible to control the supply amount so that it falls within a certain range. The ink supply timing may be appropriately set depending on the usage status of the inkjet recording apparatus, the form of the second ink tank, the ink supply means, and the like.

In addition to the configuration described above, known structures, mechanisms, inks, etc. used in inkjet recording apparatuses can be used.

[Example] The present invention will be further explained in detail by way of Examples below.

Example 1 Next, an embodiment of the present invention in which ink replenishment is performed manually will be described.

A first ink tank configured as shown in FIG. 1 is set in a conventional disposable head type ink jet printer as shown in FIG. 6 in place of the conventional ink tank to constitute an ink jet recording apparatus of the present invention. 1st
A second ink tank joint 113 is provided as an ink replenishment hole on the top surface of the ink tank, and the joint is pleated. Further, one set of bottle electrodes for detecting the amount remaining in the absorbent body is fixed at the position shown in the figure. The second ink tank for ink replenishment is approximately the same size as the first ink tank and has the configuration shown in FIG. 2, and consists of a flexible resin ink container/pressure bag 202 and an insertion tube 201. An ink retaining absorber 203 is fixed to the charging tube 201 so as to seal the tube. The ink retaining absorber is effective for preventing ink leakage when the ink tank vibrates and for preventing air bubbles from being mixed in when ink is injected.

Ink replenishment was performed as follows.

Remaining amount detection means: A set of bottle electrodes for remaining amount detection is installed inside the absorber, and the resistance between the electrodes is detected.Replenishment time: An empty warning signal is displayed on the main body or a sound is generated by detecting the remaining amount.Replenishment method...・When the user manually injects and replenishes the absorber from the second ink tank to stop replenishment...A full warning signal is displayed on the main body or a sound is generated by detecting the remaining amount. Figure 11 shows the resistance value between the electrodes of the bottle for detecting the remaining amount. When the ink is full, the resistance value is small, and as the remaining amount decreases, the resistance value increases, so when the resistance value corresponding to the time for replenishment is reached, and when replenishment is performed. The electrical signal system is set so that an empty warning and a full signal are issued when the tank becomes full and the resistance value becomes minimum.

The replenishment procedure is as follows.

■ Empty warning display ■ Printing stops and returns to home position ■ User opens the lid of the main unit and inserts the second ink tank into the first ink tank ■ Squeezes the pressure bag of the second ink tank with a finger to drain the ink inside the second ink tank Filling the 1st ink tank■ If the full warning is displayed, stop ink filling.Alternatively, a plurality of second ink tanks may be prepared, and ink may be filled by sequentially inserting them into the 1st ink tank.

According to the aspect described above, ink can be easily replenished without increasing the size of the main body of the inkjet printer or the size of the ink tank.

Embodiment FII2 Next, an embodiment of the present invention in which ink replenishment is automatically performed will be described. In this case, the ink replenishment mechanism is configured by detecting the remaining amount of ink in the first ink tank as a fluctuation in water head pressure.

The structure of the first ink tank used in FIGS. 3(a) and 3(b) is shown.
5 is provided. In addition, as electrodes for detecting the amount remaining in the absorber, a bottle electrode 111 is used on one side, and a mesh electrode 116 provided on the connecting part head side is used on the other side.The mesh electrode is fixed so as to cover the ink outlet, and the foam filter It also has the effect of preventing bubbles from being mixed in. The relationship between the resistance between the remaining amount detection electrodes and the water head pressure was as shown in FIG. Thereby, the water head pressure fluctuation warning point C and the ink replenishment stop point B can be set within a desired water head pressure range by the resistance value.

The configuration of the replenishing device built into the main body of the inkjet recording apparatus is as shown in FIG.
The ink tank (with two pipes A and B) is installed at a higher position than the first ink tank and is connected to the first ink tank by a connecting pipe 26.

A mechanical valve device 24 is provided in the middle of the connecting pipe 26, and the mechanical valve device is operated by receiving an electric signal from the remaining amount detection electrode. The mechanical valve device has a mechanism for sealing and opening the connecting pipe 26 by rotating a cam 27 as shown in FIG. The water head pressure at which the cam operates based on the signal from the electrode is set so that it is always within a substantially constant range.

Automatic replenishment is performed as follows.

Water head pressure detection means (combined as residual amount detection means): A residual amount detection bottle is provided inside the absorber, a mesh electrode is provided to cover the connecting part, and the resistance value between the electrodes is detected. Replenishment time: The water head pressure is above a predetermined value. When the replenishment is stopped, the ink will automatically start replenishing method... Automatically refill from the second ink tank located higher than the first ink tank through a mechanical valve (2nd tank > 1st tank) When replenishment is stopped...・If the water head pressure exceeds a predetermined value, the automatic replenishment procedure is as follows.

■ The remaining amount detection electrode detects the water head pressure fluctuation warning point.■ Printing is stopped and the return is made to the home position.■ The cam of the mechanical valve rotates, and the connecting pipe connected to the ink tank that received the warning is opened. , ink is replenished from the second ink tank to the first ink tank ■ The remaining amount detection electrode detects the replenishment stop point, the mechanical valve seals the tube, and replenishment is stopped. Since the first ink tank can be made smaller, the carriage can be made smaller and the burden on the carriage drive motor can be reduced, resulting in cost reductions.Also, the mesh electrode acts as a filter to prevent bubbles from entering, allowing one person to eject ink. Unstable quantities can be prevented and reliability can be improved. Furthermore, since the water head pressure can always be controlled within a certain range, the amount of ink ejected is stabilized, which has the effect of stabilizing the print quality.

Further, in the above configuration, ink replenishment is performed until the remaining amount detection electrode detects that the ink has exceeded the ink full point, and then ink suction is performed until the remaining amount detection electrode detects the ink replenishment stop point, and then it is stopped. It may be a replenishment sequence,
In this case, the precision of the mechanical valve is not required so much that costs can be reduced.

Further, an ink replenishment position may be provided at the turn-back position of the carriage, and ink replenishment may be performed during printing operation. In this case, ink replenishment can be performed without interrupting printing, thereby increasing image throughput.

[Effect of the invention] As explained above, basically the first ink tank, the second ink tank
By providing an ink replenishment mechanism consisting of ink tanks and replenishment holes that connect each tank, continuous printing operations can be easily performed without increasing the main body size, cost, or carriage drive motor torque. In addition, it is possible to prevent bubbles from being mixed in during ink replenishment, and to reduce fluctuations in water head pressure, making it possible to provide a highly reliable inkjet recording device with stable ejection characteristics.

[Brief explanation of the drawing]

Figure 1 is a schematic perspective view showing the configuration of the first ink tank head integrated cartridge used in Example 1. Figure 2 is a schematic perspective view (see-through) showing the configuration of the second ink tank used in Example 1. Fig. 3 is a schematic diagram showing the structure of the first ink tank head integrated cartridge used in Example 2, and Fig. 3 is a partially transparent perspective view;
(b) is a sectional view; FIG. 4 is a schematic diagram (partly omitted) showing the configuration of the inkjet recording apparatus used in Example 2; FIG. 5 is an explanatory diagram showing the operating state of the mechanical valve device in FIG. 4; Fig. 6 is a schematic perspective view showing the structure of a conventional disposable head type inkjet printer main body, and Fig. 7 is a schematic diagram showing the structure of a conventional disposable type ink tank integrated cartridge. (a) is a partially perspective perspective view. Fig. 8 is a diagram showing the relationship between the remaining amount of ink and water head pressure in a conventional disposable type ink tank (b is a case of an absorber with higher absorbency than a). Figure 9 is a diagram showing the relationship between head pressure and ink discharge amount in an ink tank similar to Figure 8; Figure 10 is a diagram showing a relationship between head pressure and refill frequency in an ink tank similar to Figure 8; The figure shows the relationship between the resistance value between the remaining amount detection bins (framework pins) of the remaining amount detection electrode used in Example 1 and the remaining amount of ink. FIG. 3 is a diagram showing the relationship between the inter-electrode resistance and water head pressure of the cross-section electrode. 14... Recording head 15... Carriage 16.
・Cable 17 ・Carriage motor 18 ・
...Recording medium 19...Platen 20...Feed motor 21...Shaft 22...Wire 23...
Second ink tank A (with B not shown) 24... Mechanical valve device 25... Replenishment station (can be moved when replacing the cartridge) 26... Connection pipe 27... Cam 28... Ink 41... ... Pressing member 100 ... Recording Radchip 102 ... Discharge section 102A ... Discharge port 104
... Supply tank section 110 ... Ink tank t x
t-... Electrode bottle for detecting remaining ink amount 112... Ink absorber 113... Second ink tank joint 114... Lid member 115... Ink supply window 116... Mesh electrode 200...・Second ink tank 201...insertion tube 2
02... Ink container/pressure bag 203... Ink holding absorber A... Ink full point (initial) B... Ink full stop point C... Water head pressure fluctuation warning point

Claims (1)

[Scope of Claims] 1. A first recording liquid storage member that includes a recording liquid absorber impregnated with recording liquid and has a means for detecting the remaining amount of the recording liquid in the absorber; The apparatus is mounted on a carriage in a connected state with a discharge unit that performs recording by discharging the recording liquid onto a recording medium in response to a supply of the recording liquid, and performs recording while moving the carriage relative to the recording medium. An inkjet recording apparatus that performs an inkjet recording process, characterized by having a recording liquid replenishment mechanism that replenishes recording liquid to a first recording liquid storage member at a predetermined time from a second recording liquid storage member that is not mounted on a carriage. Recording device. 2. The apparatus according to claim 1, further comprising an automatic recording replenishment mechanism that automatically replenishes the recording liquid according to the electrical output of the residual amount detection means of the first recording liquid storage member. Inkjet recording device. 3. The inkjet recording apparatus according to claim 1, wherein the ejection section that performs recording has an ejection energy generating element. 4. The inkjet recording apparatus according to claim 3, wherein the ejection energy generating element is an electric heat exchanger.