JP2010280155A - Non-solvent type ink jet printer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent a waste liquid ink from piling in the form of stalagmite. <P>SOLUTION: The ink jet printer includes a head which ejects a non-solvent ink, a waste liquid ink tank which stores the non-solvent ink ejected from the head as the waste liquid ink, and a heating means which heats the waste liquid ink. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a solventless ink jet printer that performs a waste liquid operation when a nozzle is reheated.

  Printing with fast fixing speed and glossy high-quality images with low environmental impact, printing using solvent-free inks such as UV ink and solid (wax) ink without using water or organic solvents (almost) Means are known.

  Inkjet printers are used for forming fine patterns (patterning) such as lenticular lenses and microlenses using UV curable resin.

  Solventless ink is ink that does not clog the nozzles due to drying of the solvent. However, since it is highly viscous (solid) at room temperature, it is used by heating the nozzles to reduce the viscosity (liquid).

  When printing is stopped, nozzle heating is stopped to reduce power consumption. However, when the nozzle filled with ink is cooled, a space is generated in the liquid chamber due to ink contraction. This space becomes bubbles during reheating and causes ink ejection failure.

  Therefore, at the time of reheating, a waste liquid operation (discharge) called “empty shot” is performed in order to discharge bubbles from the nozzle. This “blank shot” is performed on the waste ink tank from the print head moved to the maintenance position.

  Here, as shown in FIG. 5A, the ejected ink becomes highly viscous (solid) by cooling and accumulates in a sarcophagus shape in the waste liquid ink tank.

  As shown in FIG. 5C, the accumulated ink repeats “blank shot”, and the accumulated ink reaches a height in contact with the nozzle and stains the nozzle, causing an abnormality in printing.

  In order to prevent such a phenomenon, an operation of exchanging and cleaning the waste liquid tank has occurred despite the fact that there is a free capacity, and the productivity has been significantly reduced.

  Therefore, the invention described in Patent Document 1 discloses a technique for smoothing waste liquid ink by providing a waste liquid tank with a stirring member for stirring waste liquid ink and a cleaning means for cleaning the stirring member.

  However, the invention described in Patent Document 1 requires a stirring member and a means for cleaning the stirring member, and has a problem that the configuration is complicated and the cost is high.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a solventless ink jet printer which prevents waste ink from accumulating in a stone wall shape.

  In order to solve the above problems, a solventless inkjet printer according to the present invention includes a head that discharges solventless ink, a waste ink tank that stores the solventless ink discharged from the head as waste liquid ink, and heating that heats the waste ink. And means.

  The heating means is provided in a side portion of the waste liquid ink tank.

  The heating means is fixedly provided inside the waste ink tank.

  The heating means has a specific gravity lower than that of the waste liquid ink, and is provided without being fixed inside the waste liquid ink tank.

  The heating means has a hollow structure.

  The heating means is fixedly provided on the upper part of the waste liquid ink tank.

  According to the present invention, waste ink can be prevented from accumulating in a stone wall shape, so that productivity in maintenance can be improved.

It is sectional drawing which shows the outline | summary of deposition of the bodily fluid ink to the waste liquid tank which concerns on embodiment of this invention. It is sectional drawing which shows the outline | summary of the deposition of the bodily fluid ink to the waste liquid tank which concerns on other embodiment of this invention. It is sectional drawing which shows the outline | summary of the deposition of the bodily fluid ink to the waste liquid tank which concerns on other embodiment of this invention. It is sectional drawing which shows the outline | summary of the deposition of the bodily fluid ink to the waste liquid tank which concerns on other embodiment of this invention. It is sectional drawing which shows the outline | summary of the deposition of the body fluid ink to the conventional waste liquid tank.

  Next, the best mode for carrying out the invention will be described in detail with reference to the drawings.

  FIG. 1 is a cross-sectional view showing an outline of accumulation of body fluid ink in a waste liquid tank in an embodiment of the present invention.

  When the “blank shot” operation is performed, the ink jet print head 1 discharges ink droplets (not shown) from the nozzle toward the opening of the waste liquid tank 2 at the maintenance position.

  The waste liquid ink 3 accumulated in the waste liquid tank is heated by the heating means 41 provided at the side of the waste liquid tank so as to wrap the waste liquid tank, and is reduced in viscosity (liquid) to form a flat liquid surface. Here, SUS is used for the waste liquid tank, and an electric heater capable of temperature control by a thermocouple is used for the heating means.

  There is no need to constantly heat the waste ink. For example, if the deposit at the lower part of the nozzle surface is detected by an optical sensor, control is performed so that the waste ink reaches a certain amount before reaching the nozzle surface. Good. In FIG. 1, heating control is performed at each deposition time of (a) to (c). By heating in this way, the state at the time of each deposition can be smoothed.

  The heating temperature is preferably 50 ° C. from the temperature at which the fluidity of the waste liquid ink is flattened by its own weight.

  FIG. 2 is a cross-sectional view illustrating an outline of deposition of body fluid ink on a waste liquid tank according to another embodiment of the present invention.

  When the “blank shot” operation is performed, the ink jet print head 1 discharges ink droplets (not shown) from the nozzle toward the opening of the waste liquid tank 2 at the maintenance position.

  The waste liquid ink 3 accumulated in the waste liquid tank is heated by a plurality of long heating means 42 fixed to the bottom of the waste liquid tank to reduce the viscosity (liquid) and form a flat liquid surface. Here, SUS is used for the waste liquid tank, and an electric heater capable of temperature control by a thermocouple is used for the heating means.

  There is no need to constantly heat the waste ink. For example, if the deposit at the lower part of the nozzle surface is detected by an optical sensor, control is performed so that the waste ink reaches a certain amount before reaching the nozzle surface. Good. In FIG. 1, heating control is performed at each deposition time of (a) to (c). By heating in this way, the state at the time of each deposition can be smoothed.

  The heating temperature is preferably 50 ° C. from the temperature at which the fluidity of the waste liquid ink is flattened by its own weight.

  Further, the shape is not limited to a plurality of long shapes, and is not particularly limited as long as it is disposed on the bottom surface and can heat the waste ink from below.

  FIG. 3 is a cross-sectional view illustrating an outline of deposition of body fluid ink on a waste liquid tank according to another embodiment of the present invention.

  When the “blank shot” operation is performed, the ink jet print head 1 discharges ink droplets (not shown) from the nozzle toward the opening of the waste liquid tank 2 at the maintenance position.

  The ejected ink lands on a flat plate heating means 43 disposed on the liquid surface of the waste liquid. The heating means 43 has a hollow structure and has a specific gravity lower than that of ink. The ink that has landed on the heating means 43 is heated as necessary and flows down to the liquid surface.

  At this time, the upper surface of the ink is also heated to lower the viscosity (liquid), and the landing portion is maintained at the ink liquid level by buoyancy. That is, the waste liquid ink does not grow above the heated landing portion and spreads around the deposit slope. Here, SUS is used for the waste liquid tank, and an electric heater capable of temperature control by a thermocouple is used for the heating means.

  There is no need to constantly heat the waste ink. For example, if the deposit at the lower part of the nozzle surface is detected by an optical sensor, control is performed so that the waste ink reaches a certain amount before reaching the nozzle surface. Good. In FIG. 3, heating control is performed at each deposition time of (a) to (c). By heating in this way, the state at the time of each deposition can be smoothed.

  The heating temperature is preferably 50 ° C. from the temperature at which the fluidity of the waste liquid ink is flattened by its own weight.

  When the landing portion is covered with a material having high ink repellency such as Teflon (registered trademark) or silicon rubber, the remaining amount of the waste ink having a reduced viscosity (liquid) on the member is reduced. In the present embodiment, the landing portion 43 has a hollow structure, but may have a simple structure as long as the material has a specific gravity lower than that of the waste liquid ink.

  Further, although the present embodiment has been described as a flat plate shape, the waste ink remaining on the member is less when the landing surface is not horizontal in a shape in which the height decreases toward the outer peripheral end.

  According to this embodiment, it is not necessary to heat all the waste ink, and power consumption can be reduced.

  FIG. 4 is a cross-sectional view illustrating an outline of deposition of body fluid ink on a waste liquid tank according to another embodiment of the present invention.

  When the “blank shot” operation is performed, the ink jet print head 1 discharges ink droplets (not shown) from the nozzle toward the opening of the waste liquid tank 2 at the maintenance position.

  The discharged waste liquid ink lands on the heating means 44 that is disposed just below the nozzle surface and is as long as the width of the waste liquid tank. The landed waste liquid ink is heated as necessary and flows down into the waste liquid tank.

  Eventually, as shown in FIG. 4 (b), the waste ink accumulated in the waste liquid tank reaches the lower surface of the landing part, but does not grow above the heated landing part and spreads around the deposit slope. Become. Here, SUS is used for the waste liquid tank, and an electric heater capable of temperature control by a thermocouple is used for the heating means.

  There is no need to constantly heat the waste ink. For example, if the deposit at the lower part of the nozzle surface is detected by an optical sensor, control is performed so that the waste ink reaches a certain amount before reaching the nozzle surface. Good.

  The heating temperature is preferably 50 ° C. from the temperature at which the fluidity of the waste liquid ink is flattened by its own weight.

  When the heating unit 44 is coated with a material having high ink repellency such as Teflon or silicon rubber, the remaining amount of the waste ink having a reduced viscosity (liquid) on the member is reduced.

  In the present embodiment, the heating means 44 has a cylindrical shape, but it may be a triangular prism, a quadrangular prism, an elliptical cylinder, a semi-cylindrical cylinder, etc., and the waste ink remaining on the member is less when the landing surface is not horizontal.

  In this embodiment, it is not necessary to heat all the waste ink, and power consumption can be reduced.

  The solventless ink includes UV ink and solid ink. The UV ink is a colorless mixture of a (meth) acrylate monomer (90 wt%) and a polymerization initiator (10 wt%) and a black pigment is added at 100: 8 ( It was obtained by dispersing at a blending ratio of colorless mixture: black pigment).

The (meth) acrylate monomer may be a mixture of a plurality of monomers. The polymerization initiator may be a mixture of a plurality of polymerization initiators. The mixing ratio of the colorless mixture may be different. Furthermore, you may add a polymerization accelerator and a leveling agent suitably. The pigment may be yellow, magenta, cyan, or white. The blending ratio may not be 100: 8. In some cases it does not contain pigment (clear). You may add a dispersing agent suitably. The ink had a viscosity of 300 mPa · cm ² at room temperature and a viscosity of 20 mPa · cm ² at 50 ° C.

The solid ink was obtained by dispersing wax and black pigment at a blending ratio of 100: 8 (wax: black pigment). The pigment may be yellow, magenta, cyan, or white. The blending ratio may not be 100: 8. You may add a dispersing agent suitably. The ink was solid at room temperature and a liquid having a viscosity of 20 mPa · cm ² at 50 ° C.

  Although the embodiments have been described above, various modifications and changes can be made to these embodiments and specific examples without departing from the broad scope and scope of the present invention defined in the claims.

DESCRIPTION OF SYMBOLS 1 Print head 2 Waste liquid ink tank 3 Waste liquid ink 41-44 Heating means

JP 2008-49631 A

Claims (6)

A head that ejects solvent-free ink; and
A waste ink tank that collects solventless ink discharged from the head as waste liquid ink;
A solventless inkjet printer comprising: a heating unit that heats the waste ink.   2. The solventless inkjet printer according to claim 1, wherein the heating unit is provided on a side portion of the waste ink tank.   3. The solventless ink jet printer according to claim 1, wherein the heating unit is fixed inside the waste ink tank.   3. The solventless ink jet printer according to claim 1, wherein the heating unit has a specific gravity lower than that of the waste liquid ink, and is provided without being fixed inside the waste liquid ink tank.   5. The solventless inkjet printer according to claim 4, wherein the heating means has a hollow structure.   3. The solventless ink jet printer according to claim 1, wherein the heating unit is fixed to an upper portion of the waste ink tank.

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