JP2001287391A - Electrostatic ink jet recorder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent deterioration of printing quality due to an ink bridge which may be generated between a gate electrode and a head section in an electrostatic ink jet recorder comprising the gate electrode having an aperture section at a position corresponding to each recording electrode in the extending direction of a tip of the head section. SOLUTION: This recorder comprises a cleaning liquid circulating passage having a cleaning liquid storing section, a cleaning liquid, a cleaning liquid supplying pump, a cleaning liquid supplying pipe line, a cleaning liquid collecting pipe line and a leaning liquid collecting pump.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrostatic ink jet recording apparatus, and more particularly to an electrostatic ink jet recording apparatus which performs recording by causing toner particles in ink to fly by electrostatic force and adhere to a recording medium.

[0002]

2. Description of the Related Art In a non-impact recording method, a voltage is applied between a counter electrode provided on the back surface of a recording paper and a needle-like recording electrode opposed thereto, and a coloring material such as ink is applied by an electrostatic force of the generated electric field. There is an electrostatic ink jet recording method for performing recording by flying.

However, in the above-described conventional electrostatic ink jet recording apparatus, when vibrations due to the movement of the head are transmitted to the head, ink leaks from an opening communicating with the outside, and ink flows between the gate electrode and the recording electrode. An ink bridge that is buried occurs. When the ink bridge occurs, the flying of the ink is hindered, so that it is impossible to perform printing, and there is a problem that stable printing quality cannot be supplied.

Japanese Patent Application Laid-Open No. 11-78023 discloses a method for removing the ink bridge by providing an ink absorber to solve the above problem.

[0005]

However, the above-mentioned Japanese Patent Application Laid-Open No.
The ink absorber described in Japanese Patent No. 78023 has a problem that it will not be able to absorb the leaked ink after a long use.

Further, the discharge conduit for guiding the leaked ink to the ink absorber has a problem in that the ink continues to dry and adhere over a long period of use, so that the capillary phenomenon does not occur and eventually the leaked ink cannot be removed. is there. Due to these problems, printing quality could not be obtained for a long time.

[0007] If an ink bridge collecting tube is provided to positively absorb the generated ink bridge, the ink bridge is collected and it seems that the problem has been solved at first glance, but a small amount of ink remains on the inner wall of the collecting tube. The remaining ink eventually dries and adheres to the inner wall of the collection tube, and over a long period of time, the collection tube is eventually clogged and the ink bridge's collection ability is reduced, thereby adversely affecting printing.

An object of the present invention is to provide an electrostatic ink jet printer capable of recording a stable image for a long period even if an ink bridge occurs due to ink leakage due to head movement.

[0009]

SUMMARY OF THE INVENTION To achieve one of the above objects, the present invention provides an ink chamber, the interior of which is filled with an insulating ink containing charged toner; And a recording electrode that is positioned near the opening and discharges the toner by applying a pulse voltage, and a position corresponding to each recording electrode in the extension direction of the tip of the recording electrode. In an electrostatic ink jet recording apparatus having a gate electrode having an opening,
A cleaning liquid storage unit, a cleaning liquid, a cleaning liquid supply pump, a cleaning liquid supply pipe, a cleaning liquid recovery pipe, and a cleaning liquid recovery pump are provided.

[0010]

Embodiments of the present invention will now be described with reference to the drawings.

FIG. 1 is a schematic view of an electrostatic ink jet recording apparatus according to the present invention.

The ink reservoir 1 and the ink chamber 3 in the head 2 communicate with each other by at least one of an inflow conduit 4 and an outflow conduit 5 as viewed from the ink chamber 3. In the inflow pipe 4, there is an ink supply pump 7 for feeding the ink 6 to the ink chamber 3 in the head section 2, and in the outflow pipe 5, the ink has passed through the ink chamber 3 in the head section 2. There is an ink discharge pump 8 for returning the ink 6 to the ink storage unit 1. The head unit 2 causes the ink 6 to fly from the opening 10 according to a high-voltage pulse applied to the recording medium 11 and performs recording. As the ink 6, an insulating ink containing a charged toner is used.

In the head section 2, there are an ink chamber 3 having an opening 10 on one side, and a plurality of recording electrodes 11 for discharging toner in the ink 6 near the opening 10 by applying a pulse voltage. .

Each recording electrode 11 is provided on the front surface of the head 2.
There is a slit portion 12 for passing the toner droplet ejected by the recording electrode 11 on the extension of the tip of the gate electrode 13 and a gate electrode 13 formed of a conductive metal plate.

Next, the operation of the circulation system of the present invention will be described. An ink supply pump 7 is provided in the ink chamber 3 in the head 2.
The ink 6 is fed through the inflow pipe 4 by the operation of the ink, and the ink 6 passes through the opening 10 of the ink chamber 3, passes through the outflow pipe 5, and flows into the ink storage section 1 by the operation of the ink discharge pump 8. Flows. That is, the ink 6 flows in the circulation direction 9
Circulates in the direction indicated by the arrow.

Usually, a meniscus shape is formed in the opening 10 of the ink chamber 3 between the recording electrode 11 and the opening 10 due to the surface tension of the ink.

As shown in FIG. 2, the recording medium 22 is moving in the recording medium transport direction 21 in the direction of the arrow.
Flies the ink 6 corresponding to the image signal onto the recording medium 22 while reciprocating the head moving area 24 in the direction perpendicular to the recording medium conveying direction 21 of the recording medium 22 many times over the width of the recording medium 22. And record the images.

While the head unit 2 is moving, the recording medium 2
2 is stopped, and the head unit 2 moves while flying the ink 6 in the print area 25. The head 2 moves over the print area 25 of the recording medium 22 and temporarily stops at the non-print area 23. While the head unit 2 is stopped, the recording medium 2
2 moves one line in the recording medium transport direction 21. While the recording medium 22 is moving by one line in the recording medium transport direction 21, the head unit 2 is stopped in the non-printing area 23. When the recording medium 22 finishes moving one line in the recording medium transport direction 21, the head unit 2 starts moving in the direction opposite to the previous direction, and moves while causing the ink 6 to fly to the recording medium 22.

These reciprocating operations are repeated to form an image on a recording medium.

When the head section 2 starts or stops moving, that is, in the non-marked area 23, sudden vibrations and pressure fluctuations are applied to the head section 2 and the opening 10 of the ink chamber 3, and the ink chamber 3 and the opening 10 When the meniscus shape formed in the head portion 2 is broken, the ink 6 flows out, and the front surface of the head portion 2 comes into contact with the gate electrode 13 located at a position very close to the opening portion 10 of the ink chamber 3. JP-A-11-078023 discloses that a meniscus shape and an ink bridge are formed between them. Once the ink bridge occurs, there is a problem that printing cannot be performed thereafter and stable recording cannot be supplied.

In the present invention, as shown in FIG. 1, the cleaning liquid storage unit 14, the cleaning liquid 15, the cleaning liquid supply pump 16, the cleaning liquid supply pipe 17, the cleaning liquid recovery pipe 19, and the cleaning liquid recovery pump 2.
0 is set.

The cleaning liquid collecting pump 20 operates the head unit 2 at the position of the non-printing area 23 to suck the ink bridge generated at the position of the non-printing area 23, and
To be collected.

When the printing on the recording medium 22 is completed, for example, the cleaning liquid supply pump 16
The cleaning liquid 15 in 4 is supplied into the cleaning liquid supply pipe 17. At the same time, the cleaning liquid recovery pump 20 starts operating. The cleaning liquid 15 passes through the opening 10 as shown in the cleaning liquid circulation direction 18, flows through the cleaning liquid recovery pipe 19 by the cleaning liquid recovery pump 20, and is collected in the cleaning liquid storage unit 14. At this time, the ink supply pump 7 and the ink discharge pump 8 are stopped.

The time when the cleaning liquid supply pump 16 and the cleaning liquid recovery pump 20 start operating at the same time, that is, when the cleaning liquid recovery pipe 19 is cleaned, is after one recording medium 22 has completely passed or The power may be turned on after the inkjet printer is turned on, or the power may be turned off. Further, the operation may be started periodically.

Since the cleaning liquid 15 is a liquid for cleaning the ink 6 remaining in the cleaning liquid recovery pipe, a liquid having a lower toner particle concentration than the ink 6 is desirable. Cleaning liquid 15
May be a liquid completely free of toner particles.

As described above, the ink bridge generated in the non-printing area 23 can be recovered by a series of operations, and the ink does not adhere to the cleaning liquid recovery pipe 19, so that the ink bridge can be recovered for a long period of time and a stable image can be obtained. Can be supplied.

[0027]

According to the present invention, there is an effect that an electrostatic ink jet printer capable of recording a stable image without a print failure due to the occurrence of an ink bridge for a long period of time can be provided.

[Brief description of the drawings]

FIG. 1 is a schematic view showing an embodiment of an electrostatic ink jet recording apparatus according to the present invention.

FIG. 2 is a diagram illustrating a relationship between a recording medium conveying direction and a head moving direction according to the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Ink storage part, 2 ... Head part, 3 ... Ink chamber, 4 ...
Inflow pipe, 5 outflow pipe, 6 ink, 7 ink supply pump, 8 ink discharge pump, 9 ink circulation direction,
10 opening, 11 recording electrode, 12 slit, 1
3: gate electrode, 14: cleaning liquid storage unit, 15: cleaning liquid,
16 cleaning liquid supply pump, 17 cleaning liquid supply conduit, 18
... Cleaning liquid circulation direction, 19 ... Cleaning liquid collection pipeline, 20 ... Cleaning liquid collection pump, 21 ... Recording medium transport direction, 22 ... Recording medium, 23 ... Non-printing area, 24 ... Head moving area, 25 ...
Printing area.

Claims (4)

[Claims] An ink chamber filled with insulating ink containing charged toner; a supply pump for supplying the ink to the ink chamber; and a discharge pump for discharging the ink from the ink chamber. An opening communicating with the ink chamber to the outside, a recording electrode positioned near the opening to discharge the toner by applying a pulse voltage, and the recording electrode extending in a direction in which a tip of the recording electrode extends. And a recording head having the opening, the recording electrode, and the gate electrode ejecting the toner by the pulse voltage while moving a printing area of a recording medium. Cleaning ink storage unit, cleaning liquid, cleaning liquid supply pump, cleaning liquid supply pipe, cleaning liquid recovery An electrostatic ink jet recording apparatus having a cleaning liquid circulation path composed of a pipe and a cleaning liquid recovery pump. 2. The electrostatic ink jet recording apparatus according to claim 1, wherein the cleaning liquid supply pump operates when printing is not performed on the recording medium. 3. The electrostatic ink jet recording apparatus according to claim 1, wherein the cleaning liquid recovery pump is operated when the recording head is moved to a position other than a printing area of the recording medium and when the cleaning liquid supply pump is operated. An electrostatic ink jet recording apparatus characterized by operating in the following manner. 4. An electrostatic ink jet recording apparatus according to claim 1, wherein said cleaning liquid is a liquid having a lower concentration than said insulating ink.