JP2001253083A - Filter for ink jet printer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve clogging of the filter for ink jet printer. SOLUTION: A metallic filter 18 is provided in the ink supply system of an ink jet printer such that ink is passed through a large number of hole parts 20 of the filter 18 and filtered ink is supplied to a print head 8 wherein the opening part forming face 22 of the filter 18 in a filter unit 14 is previously subjected to electrolytic polishing.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a filter device provided in an ink supply system of an ink jet printer, and more particularly, to a filter device for preventing clogging of a filter.

[0002]

2. Description of the Related Art In an ink jet printer, a structure in which a replaceable filter is provided in an ink supply system is disclosed in Japanese Patent Laid-Open No. Hei 5-116332 or Japanese Patent No. 2992.
No. 754. The material of the filter is resin fibers such as nylon and Teflon (registered trademark),
The above publication discloses a material in which a large number of holes are formed by knitting metal fibers such as stainless steel, and a material in which holes are formed by etching a stainless steel plate.

[0003]

SUMMARY OF THE INVENTION In the case of an ink jet printer using a pigment-based ink or a solvent-based ink,
Due to the characteristics of the ink, the ink aggregates at the opening of the filter,
The opening is clogged. In order to remove clogging of the filter, the surface of the filter where the openings were formed was cleaned with an ultrasonic cleaner to remove dirt and oil from the surface where the openings were formed. According to the method (1), dust that can be mechanically peeled off and adhered to the opening forming surface of the filter can be removed. However, as shown in FIGS. Etc. could not be removed.

[0004] Further, it was not possible to remove scratches and irregularities on the opening portion forming surface 2a. These oxides and the like disturb the flow of the ink, and pigments and the like dispersed in the ink with this portion as a nucleus start to aggregate. As shown in FIGS. 5 and 6, when the aggregation 6 of the pigment starts and the effective opening area of the filter opening 2b decreases, the flow velocity of the ink passing through the opening increases. This means that the ink pigment or the like quickly passes through the narrow opening area, and when passing through, the pigment that only repels electrically receives the mechanical external force when passing, and The distance between the pigments is reduced and they are united.

That is, it has been confirmed that when clogging of the opening portion starts, the clogging proceeds rapidly. The present invention prevents the start of agglomeration of pigments and the like by smoothing the opening forming metal surface of the filter, thereby suppressing an increase in the flow rate of the ink passing through the filter and preventing the ink from passing through the filter. The purpose is to stabilize the generated pressure loss. In a print head of an ink jet printer, it is necessary to maintain a slight negative pressure on the nozzle surface, and it is very important that the pressure loss in the filter is small and that the value is stable.

[0006]

According to the present invention, a metal filter is provided in an ink supply system of an ink jet printer, and the ink is filtered through a large number of apertures of the filter. In a filter device of an ink jet printer which is supplied to a print head, an electrolytic polishing process is performed on a surface of the filter on which an opening is formed.

[0007]

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings. In FIG. 1, 8
Denotes a print head mounted on an ink jet printer (not shown), which is attached to a carriage (not shown) movable along a Y-axis rail (not shown). Four print heads 8 are mounted on the carriage, one of which is shown.

The print head 8 has a plurality of nozzles, and is configured so that ink is supplied from inside a sub-tank (not shown) via ink tubes 10 and 12. The sub tank is configured to be supplied with ink from a main tank via an ink tube. A filter device 14 is disposed in the ink supply path between the main tank and the sub tank and the ink supply path between the sub tank and the print head 8 so that the ink flowing in each ink supply path is filtered by the filter 18 of the filter apparatus 14. It is configured.

The filter device 14 includes a container 1 made of synthetic resin.
6 and a filter 1 disposed in a filter chamber therein.
8, a rubber packing (not shown) is arranged on the outer peripheral portion of the filter 18 to constitute a seal mechanism for preventing leakage of ink to the outside. Further, rubber packing prevents the ink from passing around the filter 18 and ensures that the ink passes through the filter 18.

The filter 18 has a structure in which a large number of apertures 20 are formed with a width and a diameter of several microns on a thin metal plate such as stainless steel by etching or electroforming. Further, the filter 18 may be of various structures such as a braided metal fiber such as stainless steel. The front and back surfaces of the filter 18, that is, the opening forming surface 22, are subjected to a polishing treatment by an electrolytic polishing technique to remove irregularities and oxides on the front and rear surfaces of the filter which are generated at the time of manufacturing the filter.

The electropolishing is performed in a state of an original stainless steel plate of about 50 cm × 100 cm square before the filter is mounted on the container 16. When performing electrolytic polishing, a liquid prepared by mixing 85% phosphoric acid and 95% sulfuric acid at a ratio of 1: 3 is prepared.
A pair of electrically negative copper plate electrodes is placed about 30 cm apart in a tank filled with the electrodes. Also, an electrically positive stainless steel filter plate is placed at the center of the electrode. Providing copper plates on both sides of the filter original plate
It is intended that polishing is performed evenly on both sides of the original filter. A voltage of about 12 V is applied between the electrode and the filter original plate to flow a current for 2 to 5 minutes.

[0012]

According to the present invention, since the opening forming surface of the filter is smooth, the aggregation is less likely to occur when the ink passes through the filter opening, and the ink passes smoothly. Done. Further, since the pressure loss due to clogging in the filter is small, there is an effect that the negative pressure on the head nozzle surface is stabilized.

[Brief description of the drawings]

FIG. 1 is an external view of a filter device.

FIG. 2 is an enlarged external view of a part of the filter.

FIG. 3 is an explanatory diagram of a conventional technique.

FIG. 4 is a sectional view taken along line AA.

FIG. 5 is an explanatory diagram of a conventional technique.

FIG. 6 is a sectional view taken along line BB.

[Explanation of symbols]

 Reference Signs List 2 Filter 2a Opening forming surface 4 Oxide 6 Ink aggregation 8 Print head 10 Ink tube 12 Ink tube 14 Filter device 16 Container 18 Filter 20 Opening 22 Opening forming surface

Claims (1)

[Claims] 1. A filter device for an ink jet printer in which a metal filter is arranged in an ink supply system of the ink jet printer, and ink is filtered through a plurality of openings of the filter and supplied to a print head. 3. The filter device for an ink jet printer according to claim 1, wherein an electrolytic polishing process is performed on the opening forming surface of the filter.