JPS59129161A - Printer - Google Patents

Abstract

PURPOSE:To provide the printer having a large degree of freedom for arrangement of head ink vessel, by interconnecting the lower port of main ink vessel interconnecting the head without interconnecting the atmosphere to the sub ink vessel interconnecting the position of liquid surface lower than that of head to the atmosphere. CONSTITUTION:The lower part of main ink vessel interconnecting a head 1 and cutting off from the interconnection to the atmosphere by sealing an interconnecting hole 8 and an ink feed hole 7, is interconnected to a sub ink chamber 15 by interconnecting tubes 12 and 13. The liquid surface 28 of sub ink chamber 15 is so positioned to be lower than the head 1. The hole 16 interconnecting to the atmosphere being opened and negative pressure is generated by the principle of the tumbler of chicken. The mixture of bubble to the feed path 5 is prevented by combining the air mixed in the ink at the sub ink chamber 15 into the air at the upper part of main ink chamber 6 with an interconnecting tube 12.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an ink-on-demand printing device, and more particularly to means for supplying ink to a recording head over scratches.

The ink-on-demand type head is normally supplied with negative pressure ink (MH20) to prevent ink from flowing out and ink ejection becoming unstable due to burnt nozzles.F
The negative pressure of cInH20 is generally obtained by placing the ink container below the head, and by constantly pressurizing the ink container and detecting the pressure inside the head with a pressure detector to open and close the pulp. Applying negative pressure to the ink inside the head has also not been put into practical use.

However, the negative pressure generation method described above has the drawback that the degree of freedom in pulling the entire printing device is small due to restrictions on the arrangement of the head and ink container, and the disadvantage is that the device becomes 'a#' for unscrupulous users.
“Yes fc.

Therefore, an object of the present invention is to provide a layout for a head and an ink container with a large degree of freedom in retrieval.A further object of the present invention is to provide a dynamic pressure ink supply device of Wt5ν. Niafu.

The gist of the present invention is to provide a main ink container that communicates with the head but is disconnected from external safety, a seven-way pipe that communicates the lower part of the main ink container with the subordinate ink container, and a liquid level device located at a certain position lower than the head. Negative pressure is generated by the so-called "chicken water cup" principle in a sub-ink container which is arranged in a fixed manner and has a communication hole with the atmosphere.

An embodiment of the present invention is shown in FIGS. 1 and 2. FIG. FIG. 1 is a front view seen from the feeding direction of the recording medium, and FIG. 2 is a side view seen from a direction perpendicular to FIG. 1.

In FIG. 1, reference numeral 1 denotes a recording head whose main body is made of an injection molded part of polysulfone, and about 1000 piezoelectric elements 2 are arranged on its surface. As shown in the partially broken surface, a pressure chamber 3 is provided corresponding to the piezoelectric element 2, a nozzle 4 is formed in the lower part communicating with the pressure chamber 3, and a supply path 5 is formed in the soil part. Reference numeral 6 denotes a main ink chamber with a diameter of approximately 500 mm, which is directly connected to the supply path 5 of the recording head 1 and is provided above the recording head, and an ink supply lower and a ventilation hole 8 are provided in the upper part.

Reference numeral 9 is a stainless steel filter provided on the ink supply lower, and reference numeral 10 and 11 are the lids of the ink supply lower and ventilation hole 8, which are made of butyl rubber. Reference numeral 12 denotes a first communication pipe having one end opened at the upper part of the main ink chamber 6, and 13Vi a second communication pipe having one end opened at the lower part of the main ink chamber B. 14-piece communication pipe 12
and 13. A secondary ink chamber with a capacity of approximately 2 mm opens in the secondary ink chamber 15 at a distance H below the first communicating pipe 12 nozzles 4, and opens into the secondary ink chamber 15 at a position below the first communicating pipe 12 nozzles 4.
11'' is opened into the secondary ink chamber 15 at a position further below the distance H. 16 is a ventilation hole, which opens communication with the atmosphere from the lid 17Vc. Main ink chamber 6, communication pipes 12, 13,
The secondary ink chamber 15 is an injection molded part made of polysulfon and is integrally assembled with the head 1 by solvent bonding. Reference numeral 18 denotes a thunderbolt for detecting the level of the ink 19, which is made of a stainless steel pin and is provided at the bottom of the main ink chamber 6 and the bottom of the sub-ink chamber 15. 20 is a recording medium and is connected to the nozzle 4. I will face you. 21st time will be the e-recording medium 2.
These are the paper feed roller that feeds the paper perpendicular to the drawing in FIG. 1, and the paper press roller. Pulse motor 24 K, l:, D rotation drive ζhx via paper feed roller 21 and gear 23')
. Ink droplets 25 are ejected from the nozzle 4 and adhere to the GE recording medium 20 for recording. In FIG. 2, 26 is a bed for guiding the message recording medium 20, and 27 is a lid made of silicone rubber that seals the nozzle 4 when not recording.

The operation will be explained in terms of the configuration on the edge. When not in operation, the lid 10. M, 17.27 are all closed.

When the user turns on the printing device (not shown),
First, the lid 11 of the main ink chamber is opened by a mechanism not shown ζJ1. As a result, the pressure of the air in the main ink chamber 6 and the sub-ink chamber 15 becomes approximately equal to that of the outside air. When the lid 17f of the secondary ink chamber 15 is opened after the lid 11 is closed, the pressure of the air inside the secondary ink chamber 15 becomes equal to that outside. The liquid level 28 in this attendant ink chamber 15 does not necessarily match the lower end of the first communication pipe 12, and for example, if the printing device is operated at a lower temperature than the previous time, the temperature may change. The liquid level 28 rises by the amount of pressure change caused by the change in pressure. However, if the volume of the air portion of the secondary ink chamber 15 is appropriately selected, the liquid level 28 will be lower than the nozzle 4. If the lid 27 of the nozzle 4 is lowered below the bed 26 in this state, the negative pressure of the nozzle 4 VcVi≠(force), and the ink 19 will not flow out.

The recording medium 20 is set, a signal from a III control circuit (not shown) is applied to the pressure-N element 2, and ink droplets 25 are ejected from the required nozzles 4 to print dots on the recording medium 20. By applying a signal from the illustrated control circuit to the bulk motor 24Vc and transporting the recording medium 2.0, Bunpo 1 (Figure 1) can be recorded on the recording medium. As the ink droplets 25 are ejected from the nozzle 4, the air pressure in the main ink chamber 6 decreases, and the secondary ink chamber 15 is pushed by the outside air.
The liquid level 28 of the ink inside goes down. When the liquid level 28A falls below the lower end of the communication tube 12, the air in the secondary ink chamber 15 enters the communication tube 12, rises, and reaches the main ink chamber 6. Therefore, the liquid level 287' + the communication When the flow is lower than the tracing pipe 12, outside air 7'Ii is sent into the main chamber 6, and the liquid level 28 is kept constant, so that the ink in the nozzle 4 is supplied to the back of the negative pressure door 5 of the HcrnH20. Great.

That will happen. Hid is usually selected from 1 cIn to 10 cIn, preferably 5σ. H is selected within a range that does not exceed the capillary pressure of the nozzle at the maximum. As the ink is consumed, the amount of ink 19 in the main ink chamber 6 decreases, and when the liquid level drops below the stop electrode 18, the resistance value between the electrical connections 18 changes, and a control circuit (not shown) causes the ink to end. At the same time as the display is performed, the operation of the printing apparatus is stopped, and the nozzle lid 27 and the slave ink chamber lid 17 are closed. The user opens the lid 1o of the ink supply lower and the lid 11 of the ventilation hole 8,
Ink is supplied from the ink supply lower. Then lid 10
．． 11 and resume driving as before. The opening and closing of the lids 10, 11, 17, and 27 described above may be performed by a solenoid, a combination of a motor and a cam, or even manually.

Note that the volume and shape of the secondary ink chamber 15 are the same as those of the first communication pipe 12.
If the volume of the air portion above the lower end is ■, and the horizontal cross-sectional area of the air portion of the secondary ink chamber is S, - ``H°°゛゛゛°゛■, then the temperature change is from 0℃ to 60''C. Even if the temperature changes even if the temperature changes, at the start of operation, it is possible to apply self-pressure to the heel and sod by opening and closing the lid as described in the embodiment. The constant 0.2 in Equation 0 indicates the amount of change in volume between 60°C and 0°C of air at one side pressure.

As can be seen from the embodiments described above, according to the present invention, the ink container can be placed above the head, so the degree of freedom in design is improved, and negative pressure ink can be supplied to the head with a simple mechanism. According to this embodiment, since the co-feeding path 5 of the head 1 is directly arranged at the lower part of the main ink chamber B, air bubbles generated in the ink 19 rise to the upper part of the main ink chamber 6 due to buoyancy. There is no chance of air bubbles entering the head and making injection impossible. In addition, since the five upward supply channels are very narrow, they act as a kind of air filter and help prevent bubbles from entering the head.

Also, at the start of operation, first open the lid 11f of the vent 8 of the main ink chamber B, and then open the lid 17 of the vent 16 of the migration ink chamber 15 with the lid 11 closed.

If the VC environmental temperature is high during storage of printing equipment f < tr b, the pressure inside the main ink chamber 6 will rise and the vent hole 16 of the sub-ink chamber 15 will increase.
Since the ink 19 can be prevented from flowing out to the outside, and since the supply path 5 of the head 1 is directly connected to the main ink chamber 6, there is no problem in supplying the ink 2o to the head. :
There is no pressure loss, and therefore the ejection response of the head can be improved. Especially 1000 like this example
Even in the case of multi-nozzle nozzles, there is no shortage of ink supply.

Use a pump, etc. to fill ink for the first time in the tank.
, )r<, the ink can be filled naturally by gravity by opening and closing the lid.

Since the communication pipes 12 and 13 are divided into two by the partition wall 14, the air entering the ink 19 in the secondary ink chamber 15 follows the first communication pipe 12f and connects with the air above the main ink chamber B. Since it is connected directly, there is no chance of air bubbles accidentally entering the supply path 5. However, it is also possible to omit the partition wall 14f and configure the communication pipe with only one pipe.

It is possible that the pressure in the main ink chamber 6 increases due to a rise in the environmental temperature during operation, and positive pressure is applied to the head, but if the amount of ink ejected is greater than the temperature change, this is unlikely. If this becomes a problem, the lids 11, 27 and 17 may be opened and closed in the same way as when starting the operation during the recording pause period.

In the embodiment, an ink-on-demand type head using a piezoelectric element is shown, but it can be applied to other inkjet heads and various liquid recording heads.

[Brief explanation of drawings]

FIG. 1 is a front view of one embodiment of the present invention. FIG. 2 is a side view of the embodiment of FIG. 1. 1. We recording head 4. Nozzle 5. Supply path
6. Main ink chamber 7. Ink supply port 8.
16...Through hole 10, 11.17.27...Lid 12.13...Communication pipe 15...Sub-ink chamber 20...Recording medium 9 Applicant: Epson Corporation Agent, Patent Attorney, Tsutomu Mogami

Claims (1)

[Claims] 2. A recording means for recording on a recording medium using liquid ink;
A first ink accommodating means which communicates with the recording means and is located higher than the ink outlet of the front F recording means, and which is cut off from surface communication with the atmosphere during P recording operation, and a first ink storage means which is located higher than the ink outlet of the front ME' ink outlet. A second ink storage means is disposed below, and has a ventilation hole that communicates with the outside during the printing operation, one end of which opens at the bottom of the ink storage means of the front cylinder 1, and one end of the second ink storage means that opens at the bottom of the ink storage means of the front cylinder 1; A printing device having a communication means opened at a position below the first ink outlet within the second ink storage means.