JP2002347226A - Ink jet printer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To dry and fix ink without making an apparatus large, thereby preventing a decrease in the printing quality even for a printer which prints at a high printing speed. SOLUTION: There are provided a line head having printing nozzles to the whole region of a printing width, a first drying means positioned on the upstream side of the line head for heating and drying a recording medium from the side of a non-recording face of the recording medium, a second drying means positioned on the downstream side of the line head for heating and drying the recording medium from the side of the non recording face of the recording medium after being printed, and a third drying means set to a position opposed to the second drying means for heating and drying the recording medium in a non-contact manner from the side of a recording face of the recording medium.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink jet printer, and more particularly, to an ink drying unit for drying and fixing ink printed on a recording medium by a line head in a short time to improve print quality.

[0002]

2. Description of the Related Art In a conventional ink jet printer, especially in a printer having a relatively low printing speed for personal use, the drying time of the ink is shortened by the improvement of the ink and the recording medium. Mainly by natural drying. But on the other hand,
As means for drying the ink printed on the recording medium,
Various schemes have been proposed.

[0003] The most common method is a method in which a platen provided opposite to a print head is heated to dry the ink printed on a recording medium in order to promote drying of the ink. As a method of heating a recording medium before and after printing, JP-A-2-182461 has been proposed. As disclosed in the above publication, a far-infrared heater is formed in a plate shape, and the ink and the recording paper are heated from the recording surface side of the printed recording paper by radiation of far-infrared rays. In addition, heating and drying are promoted by heating the non-recording surface of the recording paper through the hole of the paper guide. Further, a far-infrared heater was attached to a position immediately before printing to preheat the recording paper.

[0004]

The method of heating the platen portion also heats the print head, which promotes drying of the ink on the print head and causes a discharge failure of each nozzle of the print head. . This phenomenon is less affected in a serial printer where the print head is mounted on the carriage and the print head moves in a direction perpendicular to the recording paper conveyance direction and prints, but in a line printer where the head does not move, this phenomenon occurs. Notable.

Further, in the heating method using a far-infrared heater, the radiant heat due to non-contact is used, so that the heat transfer rate to the recording paper is poor. Problem arises.

Further, with respect to preheating of the recording paper, heating the recording paper immediately before the print head causes dew condensation on the print head, thereby causing a discharge failure of each nozzle of the print head.

An object of the present invention is to solve the above-mentioned problems and to dry and fix ink without increasing the size of the apparatus, even for a printer having a high printing speed, thereby deteriorating print quality. Is to prevent.

[0008]

According to the present invention, there is provided a line type ink jet printer having print nozzles over the entire printing width, which is located upstream of a line head when viewed in a recording medium conveyance direction. A first drying unit for heating and drying the recording medium from the non-recording surface side of the recording medium, and a second drying unit positioned downstream of the line head and heating and drying the recording medium from the non-recording surface side of the printed recording medium. Drying means, provided at a position facing the second drying means,
There is provided a line type ink jet printer having third drying means for heating and drying a recording medium in a non-contact manner from a recording surface side of the recording medium.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an example of an ink jet printer of the present invention will be described with reference to the drawings.

FIG. 1 is a side view showing a schematic configuration of an ink jet printer of the present invention. 100 is an ink jet printer, 1 is a line head, 50, 60, 70 are drying devices.

The line head 1 has printing nozzles for forming an image by ejecting ink droplets from the nozzles over the entire printing width. When performing color printing, the line head 1 includes a black line head 11, a cyan line head 12, a magenta line head 13, and a yellow line head 14. The nozzle surface of each line head is supported by a fixing mechanism (not shown) while keeping a predetermined gap on the platen 2. The platen 2 is used to prevent the head 3 from coming into contact with the head due to the lifting of the paper 3 as a recording medium and to increase the accuracy of the impact position of ink droplets on the paper.
In this case, a large number of holes 4 are made, and the lower part of the platen 2 is made to have a negative pressure by sucking with a blower 5 to adsorb the paper 3 to the platen 2.

The continuous paper used in the ink jet printer 100 for high-speed printing and high-speed conveyance by the line head 1 needs to fold or wind the paper 3 immediately after printing. Therefore, in order to prevent the printed ink from being transferred to an unintended sheet position, it is necessary to dry and fix the ink in a short time and reliably.

The drying device 50 includes a heater plate 51 and a heater 5.
In this configuration, the paper 3 is heated from the non-recording surface side to reduce the water content of the paper 3 to promote drying of the ink. As the heater 52 of the heater plate 51, any type of heater such as a sheath heater or a plate heater can be used as long as it is a heater directly attached to the heater plate 51.

The drying device 60 includes a heater plate 61 and a heater 6.
The printed paper 3 is heated from the non-recording surface side to dry and fix the ink. Heater plate 6
The first heater 62 is a sheath heater similarly to the heater 52,
Any heater, such as a plate heater, can be used as long as it is a type of heater directly attached to the heater plate 61. The heater plate 61 is provided with a hole 66 in the heater plate 61 to improve the thermal conductivity to the sheet 3 and suctioned by a blower 67 to increase the adhesion between the sheet 3 and the heater plate 61 to improve the thermal efficiency. Is increasing.

The drying device 70 is provided at a position facing the drying device 60 with the sheet 3 interposed therebetween, and covers the heater plate 61 with a guide plate 71 and blows hot air from the upstream side of the guide plate 71. Yes, the ink is dried and fixed from the recording surface side of the paper 3 by hot air. By sending hot air to the recording surface side of the paper 3, the temperature of the paper 3 is raised, not only to promote the effect of the ink penetrating into the paper 3 and drying, but also the surface of the paper 3 due to the heat of vaporization of ink moisture. Prevent temperature drop. Further, by lowering the vapor pressure by blowing air, evaporation of ink moisture is facilitated, and drying and fixing of the ink are promoted. The hot air transfers heat from the heater 72 to the fan 7.
3 obtained by blowing.

The heater plate 51, the heater plate 61, and the guide plate 71 have a width including the entire area in the width direction printed on the paper 3 by the line head 1.

Next, the operation of the ink jet printer of the present invention will be described.

The paper 3 is fed into the ink jet printer 100 by a tractor 21 which is driven to rotate by a driving device (not shown). Paper 3 is continuous paper,
In this example, continuous paper having pin holes at both ends of the paper will be described. In the case of pinless paper, the same operation can be performed by replacing the tractor 21 with a nipping roller.

After the paper 3 is fed into the ink jet printer 100, it is conveyed in the direction of arrow A in FIG. To remove the temper. The temperature at which the paper 3 is reconditioned is determined by the paper transport speed, the length of the heater plate 51 in the paper transport direction, and the temperature of the heater 52.
The temperature of the heater 52 is measured by a temperature detecting element 55, for example, a resistance temperature detector or a thermocouple, and is controlled to a set temperature by a temperature controller (not shown).

Next, the tempered paper 3 is conveyed while being attracted to the platen 2, and prints characters and figures by ejecting ink from the nozzles of the line head 1. Since the paper 3 has been tempered, the water content of the paper 3 has decreased, and the paper temperature has become higher than the normal temperature. Therefore, immediately after printing on the paper 3, ink penetration drying and evaporation drying start. However, since the platen 2 is not heated, the adverse thermal effect on the line head 1 is negligible.

Further, the printed paper 3 is supplied to a drying device 60.
, And is dried and fixed. Drying device 6
In the case of 0, the heater plate 61 is brought into close contact with the sheet 3 by attracting the sheet 3, and the ink is dried by heating from the non-recording surface side of the sheet 3. The drying device 70 heats the recording surface of the paper 3 and lowers the vapor pressure by hot air to accelerate the drying of the ink. The temperature at which the paper 3 is dried and fixed depends on the paper transport speed,
The length is determined by the length of the heater plate 61 and the guide plate 71 in the sheet transport direction, the temperature of the heater 62 and the hot air, and the amount of the hot air.

The temperature of the heater 62 is determined by a temperature detecting element 65,
For example, the temperature is measured by a resistance temperature detector or a thermocouple, and is controlled to a set temperature by a temperature controller (not shown). It is appropriate to change the temperature and the flow rate of the hot air according to the paper transport speed. However, even if it is constant in the high-speed transport area, there is no problem. As in other cases, the temperature of the heater 72 is also measured by a temperature detecting element 75, for example, a resistance temperature detector or a thermocouple.
The temperature is controlled to a set temperature by a temperature controller (not shown).

The paper 3 on which the printed ink has been dried and fixed by the drying devices 60 and 70 is discharged from the ink jet printer 100 by a tractor 31 which is rotated by a driving device (not shown). Paper 3 is platen 2
And the heater plate 61, the conveyance resistance of the paper 3 is large. Therefore, the tractor 31
The paper 3 is drawn in and conveyed.

In this embodiment, the drying device 50, the platen 2 and the drying device 60 are arranged linearly. However, in order to increase the adhesion between each member and the paper 3, each member is arranged with a curvature. May be.

[0025]

According to the present invention, it is possible to provide a printer that can reliably dry and fix ink without deteriorating print quality even in an ink jet printer that performs high-speed printing and high-speed conveyance using a line head. .

[Brief description of the drawings]

FIG. 1 is a schematic side view of an ink jet printer according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Line head 2 Platen 3 Paper 4, 66 holes 5, 67 Blower 11 Black line head 12 Cyan line head 13 Magenta line head 14 Yellow line head 21, 31 Tractor 50, 60, 70 Drying device 51, 61 Heater Plates 52, 62, 72 Heaters 55, 65, 75 Temperature detecting element 71 Guide plate 73 Fan 100 Inkjet printer

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2C056 EA01 EA23 EB14 EB30 EC14 EC29 FA13 HA41 HA46 HA47

Claims (2)

[Claims] 1. A line type ink jet printer which ejects ink droplets from a plurality of print nozzles arranged over the entire printing width and prints on a recording medium, wherein the ink jet printer is located upstream of a line head in a conveying direction of the recording medium, First drying means for heating and drying the recording medium from the non-recording surface side of the recording medium; and heating and drying the recording medium from the non-recording surface side of the recording medium after printing, which is located downstream of the line head. And a third drying unit provided at a position facing the second drying unit and heating and drying the recording medium in a non-contact manner from the recording surface side of the recording medium. Characteristic inkjet printer. 2. The ink jet printer according to claim 1, wherein the recording medium is a continuous paper continuously supplied in a conveying direction.