JP2000168060A - Ink jet recording apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To uniformly heat and dry each kind of full color and monochromatic printing papers without deforming the papers by arranging a halogen lamp having a radiation intensity peak at a specific emission wavelength oppositely to an image print face of the paper and varying the number of halogen lamps to be turned on or an emission duty. SOLUTION: After a paper 7 is transferred by a tractor 8 and printed by a printing head 2, the paper is dried by a drying apparatus 10. At this time, the drying apparatus 10 is constituted including a plurality of, e.g., five halogen lamps 11-15. The used halogen lamps have a radiation intensity peak in a range of 1100-1400 nm of an emission wavelength with a continuous supply of electricity. The plurality of halogen lamps are arranged to be opposite to a printed image form face of an object to be printed. Heating and drying conforming to a type of the printing paper become possible by switching the number of halogen lamps 11-15 to be turned on or a turn-on duty. Moreover, two kinds of halogen lamps of different wavelengths may be combined and controlled to be turned on.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink jet recording apparatus equipped with a drying device for ejecting ink droplets from a print head to adhere to a printing material such as paper for printing, and drying the printing material.

[0002]

2. Description of the Related Art In a conventional ink jet recording apparatus, a sheet printed by a print head is sucked by a heating plate provided at a stage subsequent to the print head and dried from the back side, but has the following disadvantages. .

[0003]

In a conventional ink jet recording apparatus, a print head is constituted by nozzles of four colors of cyan, magenta, yellow, and black, and various types of ink droplets are superimposed on the surface of a sheet of paper. The color was printed, and the printed paper was adsorbed from the back side by a heating plate and dried. Therefore, if the thermal load is uneven on the paper surface, such as when the print density is partially high, drying the entire surface of the paper with a heating plate will dry well the portions with low print density where the ink is not adhered well, The portion with high printing density where a lot of particles adhered does not rise relatively in temperature and does not dry well. As a result, the drying shrinkage of the paper is partially different, and the dried paper is deformed. Eventually, deformation of the paper after printing caused transport failures and reduced the commercial value of the printed matter.

[0004] Conventional heating from the back side of paper requires large power to heat and dry the surface to which ink droplets adhere when the paper is thick, and the heating plate when the smoothness of the paper surface is low. Did not adhere to the paper, and the paper was insufficiently dried.

In view of the above disadvantages of the prior art, the present invention grasps the radiation absorption characteristics of paper and ink pigments, pursues the radiation characteristics of a halogen lamp that compensates for the conventional disadvantages, and devises this control. By heating and drying the printed part of paper printed with various color inks without heating the blank part more than necessary, reliable, compact and inexpensive ink jet recording that reduced deformation due to paper drying Provide equipment.

[0006]

Means for Solving the Problems In order to achieve the above objects, the following three points have been focused on.

One is that the solvent of the ink, which is a wet component that needs to be dried, has penetrated into the vicinity where the ink droplet has landed. It is preferable to selectively dry the applied portion.

Secondly, in order to heat a portion printed with inks of various colors, a light source having no peak of radiation intensity in a visible light region is required. Radiation means having a peak of the radiation intensity in the infrared region is necessary because safety problems occur.

Thirdly, when printing is performed by subtractive color mixture, the color becomes darker as the colors are superimposed, and for example, the radiation absorptivity becomes higher as the color becomes darker in the infrared region. In other words, an ink jet recording apparatus that performs color printing by subtractive color mixing has a property that a portion where many ink droplets overlap absorbs more radiation from the lamp.

From the above three viewpoints, a means for drying the paper after printing with a halogen lamp having a peak of the radiation intensity in the infrared wavelength region is provided. Since the radiant energy increases as the wavelength becomes shorter, it is important to set the peak of the radiant intensity of the halogen lamp in an infrared region and a shorter wavelength region.

[0011] Further, since the halogen lamp can be heated without contact, it can be heated without being greatly affected by the smoothness of the surface of the paper. Even with this, the paper can be easily heated and dried.

In summary, an object of the present invention is to provide an ink jet recording apparatus that performs subtractive color printing by depositing ink droplets of cyan, magenta, yellow, black, etc. on a light-colored printing material in a superimposed manner. As a means for drying the printed material, the emission wavelength is 1100 by continuous energization.
The problem is solved by disposing a halogen lamp having a radiation intensity peak from nanometers to 1400 nanometers so as to face the printed image forming surface of the printing substrate.

Here, it is preferable that the number of the halogen lamps is at least two, and the number of lighting or the lighting duty of the halogen lamps can be switched according to printing conditions.

Further, it is preferable to separately provide a halogen lamp having an emission peak at a light emission wavelength of 1400 nm to 1600 nm by continuous energization, and to dry the paper by arbitrarily combining two types of halogen lamps of two wavelengths.
And the emission wavelength is from 1400 nanometers to 16
For a halogen lamp having a radiation peak at 00 nm, the emission wavelength is from 1100 nm to 140 nm.
It is preferable that a halogen lamp having a radiation intensity peak at 0 nanometers is disposed close to the downstream side in the paper transport direction.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described with reference to FIGS.
This will be described with reference to FIG.

In FIG. 1, 1 is an ink jet recording apparatus, 2 is a print head, and 10 is a drying apparatus.

The paper 7 is conveyed by the tractor 8, printed by the print head 2, dried by the drying device 10, sent to the stacker 30 by the conveyance roll 20, and folded.

The print head 2 includes a black nozzle 3, a cyan nozzle 4, a magenta nozzle 5, and a yellow nozzle 6, and superposes ink droplets ejected from each nozzle on the paper according to print information. Color printing.

The drying apparatus 10 has five halogen lamps 11 to 15 incorporated therein. this house,
The first halogen lamp composed of the halogen lamp 11 and the halogen lamp 12 has an emission color temperature of 2000 K at a continuous power supply of 200 V and 500 W, and has a radiation intensity peak at about 1500 nm. In addition, the second halogen lamp 13, the third halogen lamp 14, and the fourth halogen lamp 15 have an emission color temperature of 2400K at a continuous power supply of 200 V and 500 W, and have a peak of the radiation intensity at about 1250 nm. And the power supply phase control can reduce the duty by about 50%.

In FIG. 2, the horizontal axis represents the emission wavelength of the halogen lamp, and the vertical axis represents the radiation relative intensity of the halogen lamp and the radiation absorptance of the paper or ink pigment used in the present invention.
The curve a represents the light emission distribution of the fourth halogen lamp, the curve b represents the light emission distribution of the first halogen lamp, the curve c represents the distribution of the absorptivity of various ink pigments, the curve d represents the curve e of the distribution of the white paper, Indicated by f.

In the present embodiment, a so-called subtractive color mixture method is used in which the color gradation is expressed by overlapping ink drops. That is, when the cyan, magenta, and yellow ink droplets are slightly shifted from each other on the paper and partially overlap, the portion where cyan and magenta are mixed becomes blue, the portion where magenta and yellow are mixed becomes red, and the three colors are mixed. The overlapped portion becomes a mixed color black. In such a printing method, in drying the paper after printing while suppressing thermal deformation, a portion where many ink droplets are absorbed per unit area and a portion where no ink droplet is absorbed as a blank sheet are dried in a well-balanced manner. It is important to.

In the above gradation, as shown in FIG. 2, the radiant absorptance of the mixed color red is represented by a curve c, and the mixed color black is represented by a curve d. For example, when the lamp wavelength is 1250 nm, the red color is maximum. It has a radiation absorptivity of about 45% and a mixed black has an absorptivity of about 75%. The red print portion absorbs ink droplets by overlapping twice, and the black mixed color portion absorbs ink droplets by overlapping three times. The higher the number of ink overlaps, the higher the radiation absorption rate You can see that.

Conversely, the radiation absorptivity of white paper is as shown by a curve f, which is lower than that of the curve c. Although the absorptance of each single color of cyan, magenta, and yellow is not particularly shown,
It is distributed between the curves c and f.

Further, in FIG.
In the range from 0 nanometers to 770 nanometers, each color ink has a valley of radiation absorptivity, so that a lamp having a peak of radiation intensity in this wavelength range is not suitable for heating printed matter printed in color. . For example, when irradiating a reddish print portion with a halogen lamp having a radiation intensity peak at 700 nanometers, radiation components distributed near the peak wavelength of the radiation intensity are reflected, so that sufficient heating can be performed. Can not. Conversely, in the wavelength range shorter than the ultraviolet range, radiation energy is high and the ability to penetrate an object is increased, which poses a problem in safety management. From this point of view, in this example, a halogen lamp having a radiation intensity peak in the infrared region is preferable.

Since the radiation intensity increases as the wavelength becomes shorter, a wavelength having a relatively short wavelength is preferable even in the infrared region. Further, the radiation absorptivity of white paper tends to increase as the wavelength becomes longer in the infrared region. A halogen lamp having a radiation intensity peak of 1100 to 1400 nm is suitable. Therefore, in this example, a halogen lamp having a radiation intensity peak at 1250 nm was employed. By doing so, the portion where more ink droplets are absorbed absorbs more radiation, and the ink droplet attachment portion absorbs more radiation than the blank paper portion, so that the white paper portion Also, compared with the technique of heating the printing portion almost uniformly, the paper after printing can be dried with better thermal balance than before.

Another approach is to dry the paper with a lamp that has a peak in a long wavelength range where the absorption rate of various colors is high. In this case, one of the reasons is that the radiation energy is low due to the long wavelength. This is not practical.

The ink jet recording apparatus shown in this embodiment has a configuration in which a nozzle for black of a single color, instead of black of a mixed color, is provided to perform monochrome printing as generally performed. The radiant absorptivity of this monochromatic black is 90% or more regardless of the lamp wavelength, as shown by the curve d in FIG.
Of course, halogen lamps of 100-1400 nanometers,
Even a halogen lamp having a radiation intensity peak in a slightly longer wavelength range can dry a monochrome printed sheet.

Therefore, in the present invention, a halogen lamp having a peak at 1500 nm is mounted on a fixing device separately from a halogen lamp having a peak at 1250 nm, and under a condition where a thermal load is light such as monochrome printing. First
Fixing mainly with halogen lamps 11 and 12 of
Under printing conditions in which the thermal load is heavy such as color printing, the first halogen lamp is replaced by the second to fourth halogen lamps (13 to 1).
The combination of adding lighting of 5) was adopted.

The reason why the combination configuration is employed as described above is that the shorter the peak of the radiation intensity is, the shorter the life of the lamp is.
The lighting combinations of the lamps according to the printing conditions were considered so that the lighting time of No. 5 could be reduced. On the other hand, in the case of monochrome printing, unlike the case of color printing, ink droplets are not overlapped with each other, so that the power consumption is less than half that in the color printing mode.

The print head 2 has orifices arranged at a pitch corresponding to a resolution of 600 dpi in the longitudinal direction of each color for each color, and the paper transport direction is selected so that the transport speed of the paper is 600 dpi from the ink droplet forming cycle. Printing is performed. In the draft print mode, the paper transport speed is increased to twice the speed, and printing is performed at 600 dpi × 300 dpi. In this case, since the time required for the paper to pass through the drying device is reduced by half, the load of the halogen lamp is apparently doubled.

As a countermeasure against the above-mentioned load, in the example of the present invention, under the condition of the lightest load in the monochrome print mode and 600 dpi print mode, the first halogen lamp 1 is used.
1 and 12 are turned on, and a 50% duty cycle of the second halogen lamp 13 is added thereto, and drying is performed with three lamps. Under the conditions of full-color printing and draft mode printing with the largest load, five halogen lamps are used. The lamp was turned on at full duty to dry. For the printing conditions between these two extremes, the first halogen lamps 11 and 12
Then, for each of the three halogen lamps 13, the second halogen lamp 13, the third halogen lamp 14, and the fourth halogen lamp 15, drying is performed by combining 50% duty and 100% duty according to the printing conditions.

When the drying is performed under various conditions, the high-temperature second halogen lamp 13 to the fourth halogen lamp 15
Lighting at 0% duty was decided to be avoided in order to extend the lamp life as much as possible. The lighting arrangement of the halogen lamps is arranged such that the lower the temperature of the lamp, the more upstream the sheet is conveyed, and the higher the temperature of the lamp, the downstream. For example, when printing at 600 DPI in full color printing,
The first halogen lamps 11 and 12 are turned on in order from the upstream side, the 50% duty lighting of the second halogen lamp 13, the 50% lighting of the third halogen lamp 14, and the 100% lighting of the fourth halogen lamp 15 are performed. Dry in combination. The reason for this is that it is advantageous in terms of heating efficiency that the later the heating in time, the higher the temperature.

In the above example, two types of halogen lamps having two different peaks are combined,
Even if only the halogen lamps having a peak at 1400 nanometers are arranged side by side and the duty of each halogen lamp is made variable independently and dried, substantially the same effect can be obtained.

The conditions under which the thermal load becomes heavy include, in addition to the above-described color printing and draft printing, conditions in which the printing paper is thick card printing or printing within a predetermined time immediately after the lamp is turned on. These conditions may be added to the selection condition of the combination when lighting in combination with the lamps.

[0035]

As described above, according to the present invention,
A halogen lamp having a peak emission intensity of 1100 to 1400 nanometers is arranged to face the image printing surface of the paper, and the number of halogen lamps to emit light and the duty of light emission are made variable. 1
Since the paper after printing is dried in combination with a halogen lamp of 600 nanometers, it is possible to uniformly heat and dry various types of printing paper for full-color and monochrome printing, and relatively affect the smoothness and thickness of the paper. An inexpensive and compact inkjet recording apparatus that can be dried without receiving it can be provided.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating an example of an inkjet recording apparatus of the present invention.

FIG. 2 is a graph showing a radiation characteristic distribution of a halogen lamp and a radiation absorption rate of ink and paper.

[Explanation of symbols]

1 is an inkjet recording device, 2 is a print head, 3,
Reference numerals 4, 5, and 6 denote nozzle arrays of cyan, magenta, yellow, and black, 7 denotes paper, 10 denotes a drying device, and 11 and 12.
Denotes a first halogen lamp, 13 denotes a second halogen lamp, 14 denotes a third halogen lamp, and 15 denotes a fourth halogen lamp.

Claims (4)

[Claims] 1. An ink jet recording apparatus for performing subtractive color printing by superimposing ink droplets of cyan, magenta, yellow, black, etc. on a light-colored substrate, and drying the printed substrate after printing. An ink jet recording apparatus comprising a halogen lamp having a radiation intensity peak at a light emission wavelength of 1100 nm to 1400 nm when continuously energized, facing a printed image forming surface of a printing material. 2. The ink jet recording apparatus according to claim 1, wherein the number of the halogen lamps is at least two, and the number or the lighting duty of the halogen lamps can be switched according to printing conditions. 3. A halogen lamp having a radiation peak at 1,400 to 1,600 nm in emission wavelength by continuous energization is separately provided, and the paper is dried by arbitrarily combining two types of halogen lamps. The ink jet recording apparatus according to claim 2 or 3, wherein 4. A halogen lamp having an emission peak from 1400 nm to 1600 nm in an emission wavelength of 1100 nm to 1100 nm.
4. An ink jet recording apparatus according to claim 3, wherein a halogen lamp having a radiation intensity peak at 400 nanometers is arranged close to the downstream side in the paper transport direction.