JPH06171126A - Thermal printer and its recording method - Google Patents

Abstract

PURPOSE:To perform thermal transfer printing in multiple colors on a piece of recording paper having a low-smoothness and eliminate the need of an ink sheet which turns into refuse, by a method wherein solid inks are melted by the heat of a thermal head and images in two or more colors are once transferred and superimposed on an intermediate transfer medium and then transferred on the recording paper at a time. CONSTITUTION:A thermal printer is provided with an intermediate transfer medium 28, an ink cartridge 21 where two or more solid inks 22-25 are slowed and a thermal head 27. The thermal transfer printing is carried out in two steps: first and second transfer steps. In the first transfer step to form images on the intermediate transfer medium 28, a heat energy is imposed on the intermediate transfer medium 28 from behind by the thermal head 27 to melt the solid inks which are in contact with the surface of the intermediate transfer medium 28. In the second transfer step, the image on the intermediate transfer medium 28 is retransferred on a piece of recording paper 29. The ink cartridge 21 contains two or more solid inks 22-25 and is turned so that other contact faces of the ink cartridge 21 are brought in contact with the intermediate transfer medium 28. Thereby, images in two or more colors are superimposed on the intermediate transfer medium 28 and formed into a multi-color image. After that, the multicolor image is transferred on the recording paper 29 in one transfer step.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermal printer including a thermal head, solid ink and an intermediate transfer medium,
In particular, the present invention relates to a thermal printer which is provided with means for switching and using a plurality of solid inks and is capable of mono-color or multi-color printing on recording paper having low surface smoothness such as plain paper and bond paper.

[0002]

2. Description of the Related Art The structure of a conventional thermal printer using an intermediate transfer medium will be described with reference to the drawings. FIG. 2 shows JP-A-62.
This is the configuration disclosed in Japanese Patent Publication No. 80065. In this figure, reference numeral 5 denotes a recording medium such as paper, which is sandwiched between the platen roller 6 and the endless belt tension conveyance roller 7. Reference numeral 2 is a solid ink roller on the periphery of which a thermoplastic resin-based ink in which a pigment is dispersed is applied. The ink roller 2 and the endless belt 1 which is the intermediate transfer medium.
A thermal head 3 capable of selectively emitting thermal energy is arranged at a position opposed to each other. The ink roller 2 rotates in the arrow direction at the same speed as the movement of the endless belt 1 in the arrow direction.
A heat roller 4 for smoothing the ink surface on the ink roller 2 and further preheating is arranged.

The operation of the printer configured as described above will be briefly described. When the thermal head 3 generates heat, the endless belt 1 which is an intermediate transfer medium is passed through the ink roller 2
The above ink is softened to obtain an inverted print on the endless belt. This is sent to the recording medium side to be recorded by the endless belt tension transport roller 7, and the reverse printing obtained on the endless belt is pressure-transferred to the recording medium 5 to obtain the print 8. In this method, since the transfer to the recording medium 5 is entirely performed by pressure, there is no need to heat the endless belt or the platen roller, and no residual ink cleaner is required, but both the heating means and the cleaning means are required. It can also be provided.

As another conventional structure, there is a structure disclosed in Japanese Patent Laid-Open No. 2-265757 shown in FIG. In this figure, 10a is a writing section for writing on an intermediate transfer medium, and 10b is a transfer section for recording paper. A rubber blanket drum 11 is rotatably supported. Reference numeral 12 is an electric recording head, and 13 is an electric recording sheet. The electric recording head 12 and the electric recording sheet 13 are arranged so as to form an image on the surface of the rubber blanket drum 11. Reference numeral 14a is an image of the heat-meltable ink formed on the surface of the rubber blanket drum 11. Reference numeral 15 is a halogen lamp, and 16 is a reflecting mirror, which is arranged to collect the light of the halogen lamp 15 and irradiate the image 14a of the heat-meltable ink. Reference numeral 17 is an image receiving paper, and 18 is a backup roller. 14b is an image of the heat-meltable ink transferred to the image receiving paper 17.

The operation of the printer thus constructed will be briefly described. In the writing section 10a, the energizing recording head 12 uses the heat-meltable ink applied to the energizing recording sheet 13 in the rubber blanket drum 11 by a known method. Transfer to. In the transfer by the electrification recording, since the surface smoothness of the rubber blanket drum 11 is sufficiently high, a clear image with high resolution which is the original of electrification recording is formed.

Next, the image 14a of the heat-fusible ink formed on the rubber blanket drum 11 is sent to the transfer section 10b by the rotation of the rubber blanket drum 11 shown by the arrow. At the transfer portion 10b, the light from the halogen lamp 15 is condensed by the reflecting mirror 16, and the image 1 of the heat-meltable ink is formed.
Irradiate 4a.

Since black ink absorbs light well, it generates heat and reaches a temperature above its melting point and melts. At this time, the backup roller 18 is biased to the rubber blanket drum 11, and the image receiving paper 17 is inserted therebetween, and the elasticity of the rubber blanket drum 11 causes the image 1 of the heat-meltable ink to be transferred.
4a is made to follow the unevenness of the image receiving paper 17. The position where the light of the halogen lamp 15 is irradiated is changed to the image 14a of the heat-meltable ink.
Immediately before the position where the image-receiving paper 17 and the image-receiving paper 17 come into contact with each other, the image 14a of the heat-meltable ink comes into contact with the image-receiving paper 17 in a molten state.

Here, only the black ink is heated by the light irradiation of the halogen lamp 15, and the other members are not heated. Therefore, the image 14a of the hot melt ink is cooled below the melting point by the rubber blanket drum 11 and the image receiving paper 17 immediately after coming into contact with the image receiving paper.

Both of the above two are the same in that they use an intermediate transfer medium, and once they are transferred onto the intermediate transfer medium and then re-transferred onto the recording paper, the offset method is adopted, but the ink supply is the same. There are differences in the method.
Also, the latter is a case of energization recording, but it is also a method applicable to a normal thermal printing method.

[0010]

However, the above-mentioned configuration has the following problems. First of all, it is difficult for both of them to obtain a multicolored recorded image.

In the latter case, in particular, in order to perform multicolor recording, the units 10a each consisting of an ink sheet and a thermal head are prepared by the number of colors, or like the ink sheet of a conventional thermal printer. In addition, it is necessary to use an ink sheet in which inks of the number of colors are sequentially applied, which causes a cost increase.

A waste material called a used ink sheet is generated. There is also a problem. Therefore, the present invention has been made by paying attention to the above points, and enables printing of a plurality of colors with good image quality even on a recording medium having a low surface smoothness, and further, an ink sheet as waste An object is to provide a thermal printer that does not generate.

[0013]

In order to solve the above problems, in the present invention, an intermediate transfer medium, a solid ink, and an ink cartridge containing the solid ink,
In a thermal printer including two transfer steps including a thermal head, in the first transfer step, thermal energy is selectively applied from the back surface of the intermediate transfer medium by the thermal head to urge the surface of the intermediate transfer medium. The solid ink thus melted is melted to form an image on the surface of the intermediate transfer medium, and in the second transfer step, the image formed on the intermediate transfer medium is retransferred to a recording paper, and the ink cartridge is The above problem is solved by providing the ink cartridge with means for accommodating a plurality of solid inks and switching the type of the solid inks urged to the intermediate transfer medium.

[0014]

According to the above construction, after the image of the first color material is transferred onto the intermediate transfer medium, the contact surface between the ink cartridge and the intermediate transfer medium is switched to further develop the image of the second color material. It is possible to transfer the desired color image onto the recording paper in one step after transferring and forming a color image composed of a plurality of color materials on the intermediate transfer medium by the same process.

Further, it is not necessary to newly provide a thermal head as much as the number of colors increases, and a used ink sheet treated as waste is not generated.

[0016]

An embodiment of the present invention will be described below with reference to the drawings. As shown in FIG. 1, the solid Y (yellow) ink 22, the solid M (magenta) ink 23, the solid C (cyan) ink 24, and the solid B (black) ink 25 are housed in an ink cartridge 21. The ink cartridge can be rotated around the rotation pin 26 by a driving force such as a motor (not shown).

Further, a thermal head 27 is arranged at a position in contact with these solid inks, and a transfer belt 28 which is an intermediate transfer medium is sandwiched between the thermal head 27 and the solid inks. The transfer belt 28 is tensioned by the transport roller 32.
The carrying roller 32 serves to carry the transfer belt 28.

Further, the transfer belt 28, on the other hand, is provided with a backup roller 32 and a platen 31, and the recording paper 2
9 and the transfer belt 28 are pressed and brought into close contact with each other. Therefore, this method is an offset method, and the printing conditions from the solid ink to the intermediate transfer medium are always the same regardless of the type of recording medium, and the transfer conditions from the intermediate transfer medium to the recording paper (for example, transfer pressure and If the transfer temperature and the like) are optimized, it is possible to transfer the ink image 33 on the transfer belt 28 to a recording paper having low surface smoothness such as rough paper or bond paper.

In the following, the operation will be described by taking as an example the case of printing with three colors of Y (yellow), M (magenta) and C (cyan). First, the mechanism (not shown) releases the contact and separation between the platen 31 and the backup roller 32,
Rotate the ink cartridge 21 in the a direction to remove solid C
Fix the ink 24 at the position where it contacts the thermal head,
Then, while the transfer belt 28 is being transferred in the b direction by the transfer roller 32, electric power is simultaneously supplied to the corresponding heating elements of the thermal head 27, thereby transferring the transfer belt 28.
A two-dimensional image 33 of a cyan component is formed on the top.

Further, the ink cartridge 21 is rotated in the direction a, and the solid M ink 23 is fixed at the position where it abuts against the thermal head. Then, the transfer belt 28 is transferred in the direction b by the transfer roller 32, and at the same time, the thermal head 27 is transferred.
By supplying electric power to the image, a magenta component image is formed on the cyan component image on the transfer belt 28.

By repeating the same process two more times, three color images of Y (yellow), M (magenta) and C (cyan) are formed on the transfer belt 28 in an overlapping manner. As shown in FIG. 4, the state on the transfer belt at this time is that the Y, M, and C inks are transferred as mirror images in order from the outside.

Finally, after supplying the recording paper 29 between the platen 31 and the backup roller 32, these two rollers are pressed, the image on the transfer belt 28 is pressure-transferred onto the recording paper 29, and the desired recorded image 30 is obtained. To get As a result, an image on which Y, M, and C inks are transferred from the recording paper side is obtained on the recording paper as shown in FIG. in this case,
The backup roller 32 and the platen 31 may be heated. Further, a cleaner for remaining ink on the transfer belt 28 may be provided.

Further, for example, when it is desired to print only in black, it is sufficient to transfer only the image of the solid B ink 25 to the transfer medium and then retransfer to the recording paper. The same applies when printing only two colors of preference. In the present embodiment, the case where the transfer belt is used as the intermediate transfer medium is shown, but the present invention is not limited to this, and the present invention has the same effect even when applied to a drum-shaped intermediate transfer medium. Is obvious.

[0024]

As described above, since the solid ink is once transferred to the intermediate transfer medium by the heat of the thermal head, and the images of a plurality of color materials are superposed on each other, the solid ink is transferred onto the recording paper all at once. There is little color misregistration, and in addition to plain paper printing, which is a feature of the thermal offset method, good multi-color printing is possible. Moreover, it is very economical because it consumes only the ink that has been used, and because it does not use an ink sheet, it does not generate waste like the conventional thermal printer and has no environmental impact.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing an embodiment of a thermal printer according to the present invention.

FIG. 2 is an explanatory diagram showing an example of a conventional thermal printer.

FIG. 3 is an explanatory diagram showing an example of another conventional thermal printer.

FIG. 4 is an explanatory diagram of an ink image on a transfer belt by the thermal printer of the present invention.

FIG. 5 is an explanatory diagram of an ink image on recording paper by the thermal printer of the present invention.

[Explanation of symbols]

 21 Ink Cartridge 22 Solid Y Ink 23 Solid M Ink 24 Solid C Ink 25 Solid B Ink 26 Rotating Pin 27 Thermal Head 28 Transfer Belt 29 Recording Paper 31 Platen

Claims (2)

[Claims] 1. An ink cartridge containing at least one color of solid ink, a thermal head for selectively applying thermal energy, and an intermediate transfer medium for transferring an image of the fixed ink melted by the thermal head onto a surface thereof. And a retransfer unit that retransfers an image on the intermediate transfer medium to a recording medium, and a switching unit that switches a contact surface between the ink cartridge and the intermediate transfer medium. 2. An intermediate transfer medium, a solid ink, an ink cartridge containing the solid ink, and a thermal head, wherein thermal energy is selectively applied from the back surface of the intermediate transfer medium by the thermal head, First, a transfer process of melting a solid ink brought into contact with the surface of the intermediate transfer medium and forming an image on the surface of the intermediate transfer medium with a desired ink color is repeatedly performed on the intermediate transfer medium. And a second transfer step of re-transferring the image formed on the intermediate transfer medium to a recording paper.