JPH0453768A - thermal transfer printer - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] This invention relates to prevention of electrostatic adhesion of dust to print paper in a thermal transfer printer.

[Conventional technology]

FIG. 4 shows a conventional paper conveyance mechanism in a thermal transfer printer. In the figure, ■ is an ink sheet feeding side bobbin, 2 is a winding side bobbin, 3 is an ink sheet coated with hot melt ink, 4 is a thermal head, 5a is printing paper in the paper cassette 10, 5b is being printed 5c is the print paper after printing, 6 is a platen roller, 7a and 7b are pinch rollers, 8a to 8c are paper conveyance guides, and 8d is a tray having a paper stunker part 8e and a paper temporary evacuation part 8f. be. Further, 9a is a paper feeding pitch roller, and 9b to 9e are paper conveying rollers.

In this thermal transfer printer, print paper 5a in a cassette 10 is pitch-amplified by a pitch roller 9a, sent by transport rollers 9b and 9c, and sent to a platen roller 6 along a paper transport guide 8C. The print paper 5b sent to the platen roller 6 moves together with the ink sheet 3 by rotating the platen roller 6 in the right direction in the figure, and during this time, the ink on the ink sheet 3 melted by the heat generated by the thermal head 4 is removed. In the case of a color printer, after the thermal head 4 leaves in the H direction for printing the next color, the tray is temporarily retracted through the path CP between the paper conveyance guides 8a and 8b by reverse rotation of the platen roller 6. It is sent to section 8f. The print sheets 5C on which images have been printed in a predetermined number of colors are sequentially stacked on the stacker portion 8e of the tray 8d after the printing is completed.

[Problem to be solved by the invention]

As shown in FIG. 5, the printed paper 5b, which has been sent to the temporary retraction section 8r for printing the next color, has the ink 5-1 transferred to it, and the pinch roller 7a and the thermal head 4. Due to the friction caused by the pressure on the platen roller 6, and the antistatic treatment applied to the print paper loses its effect due to the heat of the thermal head 4, it becomes charged (+) and is induced by this charge. The dust C on the guide surface of the temporary retraction section 8f having a negative charge (-) is attracted to and adheres to the print paper 5b. Dust C
When the next color is printed on the print paper 5b on which the ink sheet 3 is attached, as shown in FIG. 6, the dust C interferes with the adhesion between the ink sheet 3 and the print paper 5b, resulting in white spots as shown in FIG. This causes print defects.

This invention was made to solve the above problem.
It is an object of the present invention to provide a thermal transfer printer that can prevent printing defects caused by dust adhesion on a paper conveyance path and obtain higher image quality than conventional ones.

[Means to solve the problem]

To achieve the above object, the present invention provides a thermal transfer printer having a paper conveyance path for transporting print paper sent to a platen roller to a temporary evacuation section, in which paper guides in the temporary evacuation section are rail-shaped guides spaced apart from each other by a predetermined distance. The structure is as follows.

In the second aspect of the present invention, the ceiling surface that is separated by a predetermined distance from the guide surface on which the print paper of the temporary retraction section is placed is made of a conductive material, and this conductive material is grounded.

[Effect]

In this invention, the print paper is held in a floating state from the bottom surface of the temporary retraction section by the rail-shaped guide, so that
Even if the print paper is electrically charged, there is almost no chance that dust on the bottom surface will electrostatically adhere to the print paper.

In addition, in the invention of claim 2, an amount of opposite charge corresponding to the charge on the print paper is supplied to the conductive material and the charge is canceled out, so that charging of the dust IW is prevented, and the dust on the print paper is Electrostatic adhesion of types is prevented.

〔Example〕

Hereinafter, one embodiment of the present invention will be described with reference to the drawings.

In FIG. 1, 8D is a tray, which is the same as the tray 8d in FIG. 4 in that it includes a stunker part 8e and a temporary evacuation part 8f, but the temporary evacuation part 8f is on both sides of the upper and lower intermediate parts. It differs from the tray 8d in that it has rail-shaped guides 8fL and 8fR.

In this configuration, the print paper 5b is printed in a certain color and sent to the temporary storage section 8r for printing in the next color.
is supported by guides 8fL and 8fR, and floats at a predetermined distance from the bottom surface 8g of the temporary retraction section 8f, so that even if there is dust C on the bottom surface 8g, the charged print paper 5b will not be dusty. There is no force to electrostatically attract C types beyond the above-mentioned interval, and dust C types are prevented from adhering to the print paper 5b.

FIG. 2 shows another embodiment of the present invention, in which a conductive sheet 8i is attached to the upper base 8h of the temporary retraction section 8f, and the conductive sheet 8i is electrically grounded. This is different from the embodiment shown in FIG.

In this configuration, the conductive sheet 8i receives a reverse charge (-) induced by the charge (+) of the printing paper 5b, and as shown in FIG. ) is supplied, the amounts of both charges are almost balanced, so the print paper 5b does not appear to have an upper band shape, and the (-) charge of das)C is prevented, so the print paper 5b The amount of adhesion of dust C is smaller than in the case of FIG.

Incidentally, the same effect can be obtained even if this conductive sheet 81 is provided on the ceiling surface of the temporary retraction section 8f in the tray 8d in FIG. 4.

Furthermore, although the above embodiment deals with the temporary retraction section 8f of the tray, the present invention can be implemented in other sections of the paper conveyance path to obtain similar effects.

Furthermore, in the embodiment shown in FIG. 2, the conductive sheet 8i was provided on the side surface of the temporary retraction section 81 of the tray 8D, but the tray 8D
The entire structure may be made of a conductive material and electrically grounded.

Furthermore, the present invention exhibits similar effects even when the printing target is printed on a polymer film instead of printing paper.

〔Effect of the invention〕

As explained above, this invention can weaken the dust suction force caused by the charge on the print paper or cancel the charge, thereby preventing dust from adhering to the print paper and improving the print quality compared to the conventional method. It can be used to improve credibility.

[Brief explanation of the drawing]

1 and 2 are respectively front views showing an embodiment of the present invention, FIG. 3 is a diagram for explaining the operation of the above embodiment, and FIG. 4 is a configuration diagram showing a paper conveyance mechanism of a thermal transfer printer. FIG. 5 is a diagram for explaining the charging of printing paper, FIG. 6 is a diagram for explaining the occurrence of printing defects due to this charging, and FIG. 7 is a diagram showing printing defects. In the figure, 3--in-sheet, 4--thermal head, 6-platen roller, 8a-8C-paper conveyance guide, 8D--tray, 8f--temporary evacuation section, 8fL,
8fR - rail-shaped guide, 8 toe - conductive sheet. In addition, in the figures, the same reference numerals indicate the same or corresponding parts.

Claims (2)

[Claims] (1) A thermal transfer printer having a paper conveyance path for transporting print paper sent to a platen roller to a temporary evacuation section, characterized in that the paper guides of the temporary evacuation section are rail-shaped guides spaced apart from each other by a predetermined distance. Thermal transfer printer. (2) In a thermal transfer printer that has a paper conveyance path that sends print paper sent to a platen roller to a temporary evacuation section, the ceiling surface of the temporary evacuation section opposite to the surface on which the print paper is placed is covered with a conductive material, and the A thermal transfer printer characterized in that the conductive material is electrically grounded.