JPS61121951A - Ink jet recording apparatus - Google Patents

Abstract

PURPOSE:To miniaturize the titled apparatus by dispensing with an ink recovery pump and to eliminate erroneous printing due to the mixing of air bubbles, by naturally recovering caught ink by arranging a gutter at a position higher than the max. liquid level in an ink tank. CONSTITUTION:The ink droplet injected from an ink jet head 1 is charged by a charging electrode 2 and deflected by a deflection electrode 3 to be impinged to the recording paper on a platen 2 but an uncharged ink droplet straightly advances to enter a gutter 4. Because the gutter 4 is arranged at a position higher than the max. liquid level in an ink tank 5, ink is naturally fallen to be returned to the ink tank 5 through an ink recovery filter 8. Therefore, an ink recover pump or tube becomes unnecessary and the apparatus can be miniaturized and, because the evaporation of the ink from a tube is eliminated, the erroneous printing of the head due to the mixing of air bubbles is avoided.

Description

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

Conventional inkjet recording apparatuses have already been proposed in various ways. Regarding the ink circulation system, for example, (1) a recording head section and a gutter are mounted on a carriage, and an ink supply pump and an ink recovery pump are provided.

(2) The ink supply pump is also mounted on the carriage, but there are some with the ink tank located outside the carriage. It is necessary to connect the components on the carriage and the components outside the carriage with a flexible tube, which increases the size of the device.In addition, the ink in the tube evaporates and air enters, creating bubbles in the head and causing vibration. There were drawbacks such as decreased efficiency and further erroneous printing.

1. The present invention was made in view of the above-mentioned circumstances.
In particular, this was done with the aim of eliminating the ink tube that connects the components on the carriage and the components outside the carriage, thereby making the device smaller and lighter, and further improving printing quality by eliminating the evaporation of ink from the tube. It is something that

Structure: In order to achieve the object described in item 1, the present invention includes an ink tank, an ink supply pump, an inkjet head, a gutter, etc. placed on a carriage, and ink is supplied from the inkjet head while the carriage is moved relative to a recording medium. An inkjet recording device that performs recording by ejecting droplets, characterized in that the gutter is disposed above the highest liquid level in the ink tank, and the ink captured by the gutter is naturally collected. This is what I did.

Hereinafter, the present invention will be explained based on examples.

FIG. 1 is a perspective view of essential parts showing an example of an inkjet recording apparatus according to the present invention, and FIG. 2 is a cross-sectional configuration diagram.
0 is the carriage, 20 is the platen.

30 is an ink supply pump section, and the carriage 10 is connected to a carriage guide rod 11.30, as is well known. Sub guide rod 12. The carriage is reciprocated and scanned in the direction of the arrow by the carriage scanning belt 13 or the like.1. The electrical members of the carriage 10f are electrically connected to electrical members outside the carriage via the wire harness 14. Further, 1 is an inkjet head 52, a charging electrode 53 is a deflection electrode, 4 is a gutter, 5 is an ink tank, 6 is a diluent tank, 7 is a valve, 8 is an ink recovery filter, and 9 is an ink supply filter, as is well known. Then, ink droplets are ejected from the inkjet head 1, and the ink droplets used for printing are charged by the charging electrode 2 according to the printing information signal, deflected by the deflection electrode 3, and then onto the recording paper on the platen 20. Ink droplets that are collided and are not used for printing are allowed to travel straight without being charged or deflected, and are captured by a gutter 4, and the captured ink droplets are collected into an ink tank 5 through a collection filter 8 and reused. The ink in the ink tank 5 is supplied to the ink supply pump unit 30 through the ink supply filter 9, pressurized by the pressure pump, and supplied to the inkjet head l via the valve 7. Accordingly, in the present invention, the ink tank 5. The diluent tank 6, the valve 7, and the ink supply pump section 30 are mounted on the carriage 10, and these ink tanks 5.
The diluent tank 6, valve 7, and ink supply pump 30 are connected in the lower base, and as described above, the ink in the ink tank 5 is pressurized by the ink supply pump section 30, and the valve 7 is turned on. At this time, the inkjet head 1 jets the ink through the valve.

The uncharged ink droplets go straight and enter the gutter 4 as described above, and the ink that has entered the gutter 4 falls naturally and returns to the ink tank 5. At this time, ink tank 5
If the highest liquid level is set lower than the gutter 4, natural recovery is guaranteed and a conventional recovery pump is no longer necessary. In addition, if the ink tank is on the carriage, the operator can easily replace the ink, similar to replacing the cartridge in an impact printer.If the ink tank is about 20cc, the replacement cycle will be more than 10 days, which is less inconvenient for the operator. I won't give it. Also, there are no tubes from the valve to the inkjet head and from the gutter to the ink tank (
This eliminates the need for special wiring harnesses, reducing costs.

FIG. 3 is a configuration diagram showing an example of the ink supply section 30, in which 31 is a valve catcher, 232 is an ink pressurizing pump, 33 is a tecumulator, 34 is an ink flow rate detection circuit, 35 is a pump driver, and a gutter The flow rate of the ink collected in step 4 is detected by the flow rate detection circuit 34, and the pump driver 35 is excited to drive the ink pressure pump 32. When the ink pressurizing pump 32 is driven, the ink in the ink tank 5 flows into the valve catch 31. Ink pressure pump 32. Accumulator 33. The ink is supplied to the inkjet head 1 through the valve 7, and is ejected from the inkjet head 1. In addition, in the valve catcher 31, 31a is an air trap filter, and 31b is an air vent hole.

Further, in the ink pressurizing pump 32, 32a is an armature, 932b is an ink liquid chamber, 32C is a suction valve, 32d
is the discharge valve. Conventionally, a low frequency pump of 2 to 3 Hz was used as the ink pressure pump, but if a high frequency driven pump is used as the ink supply pump, the accumulator can be made smaller. By using this, the accumulator can be constructed from a stainless steel plate with a diameter of 30 mm and a plate thickness of 0.5 mm, and it takes up almost no space.

The diluent is injected into the ink tank by detecting the viscosity of the ink and opening the valve 7 to compensate for water evaporation during circulation.

As is clear from the explanation in Section 2, according to the present invention, an ink recovery pump, tubes, etc. are no longer necessary, so it is possible to downsize the device and reduce costs. Furthermore, since the ink no longer evaporates from the tube, erroneous printing by the head due to air bubbles is eliminated. Furthermore, the use of a high frequency pump has the advantage that the accumulator can be made smaller and can be installed in a smaller space.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of essential parts showing an example of an inkjet recording apparatus according to the present invention, FIG. 2 is a cross-sectional configuration diagram, and FIG.
FIG. 3 is a diagram showing details of an ink supply system. 1... Inkjet head, 4... Gutter, 5...
... Ink tank, 6... Diluent tank, 7... Valve. 10... Carriage, 20... Platen, 30...
- Ink supply unit, 32... ink pressure pump.

Claims (2)

[Claims] (1) Place an ink tank, an ink supply pump, an accumulator, an inkjet head, a gutter, etc. on a carriage, and perform recording by ejecting ink droplets from the inkjet head while moving the carriage relative to the recording medium. An inkjet recording apparatus, characterized in that the gutter is disposed above the highest liquid level in the ink tank, and ink captured by the gutter is naturally collected. (2) The driving frequency of the ink supply pump is 10Hz.
An inkjet recording apparatus according to claim (1), characterized by the above.