JPH04223183A - Paper passage device of printer - Google Patents

Abstract

PURPOSE:To achieve prevention of printing quality from deterioration in the case where elastic force of card board and paper is much by a method wherein a passage of paper on an extended line of the paper pinched between a platen and a printing head is bent in a platen direction by a paper-presser part provided near the printing head. CONSTITUTION:In a state wherein a thermal head presses paper 7 and an ink ribbon 6a by putting them between the thermal head 4 and a platen 5, an overhang part 20a is provided to a part of a paper-presser part 20. Then, through the paper 7 sent with a feed roller 8 rotating in the arrow A direction while being pinched between the thermal head 4 and the platen 5, it is going to go in the arrow C direction when elasticity of the paper 7 is much. Herein a passage of the paper 7 is bent in the full line derection as given in the figure against the elastic force of the paper by the overhang part 20a. Even in the case where the elastic force of the paper 7 is much, the thermal head 4 have sufficient pressing force on the paper 7, and excellent printing quality can be obtained thereby.

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a paper path device for a printer having a printing head that transfers ink from an ink ribbon onto paper for printing. 2. Description of the Related Art FIGS. 3 and 4 are cross-sectional views of a printing head and a paper path device of a conventional printer. In the figure, numeral 7 denotes printing paper (hereinafter referred to as paper), which is wound around a feed roller 8 and fed in the direction of arrow A as the feed roller 8 rotates. Reference numeral 9 denotes a pinch roller unit, which exerts a pressing force on the feed roller 8 by means of a pinch roller spring 10, and plays the role of wrapping the paper 7 around the feed roller 8. After being fed in the direction of arrow A, the paper 7 passes over the top surface of the platen 5. 1 is a carriage, and the guide rail 18 of the frame mounting plate 3
and carriage shaft 2, and is movable parallel to the axis of feed roller 8. The carriage 1 is provided with an ink ribbon cassette 6 containing a thermal transfer ribbon and a thermal head 4, which move as the carriage 1 moves. The thermal head 4 is constantly biased around the carriage shaft 2 in the direction of arrow B by a tension spring 12, and is in the state shown in FIG. 3 except during printing. During printing, in the state shown in FIG. 4, the thermal head 4 is pressed in the direction of the platen 5 to transfer the ink on the thermal transfer ribbon onto the paper 7. A motor 13 is fixed on the carriage 1, and rotation is transmitted to an intermediate gear 15 and a cam gear 16 by a pinion 14 provided on the shaft of the motor 13. The cam gear 16 has a coaxial cam 19, and the rotation of the cam 19 rotates the cam follower 17 around a support shaft (not shown), thereby creating a helical winding fixed on the cam follower 17. The coil spring (pressing spring) 11 is moved in the direction of the platen 5. As a result, the thermal head 4 is pushed in the direction opposite to the arrow B against the tension spring 12, and as shown in FIG. Place both of them on platen 5.
to print the ink on the thermal transfer ribbon onto the paper 7. In the state shown in FIG. 4, at the same time as the thermal head 4 presses the paper 7, the paper pressers 20 provided on both sides of the thermal head 7 press the paper 7. Problems to be Solved by the Invention [0003] With the configuration of the conventional example described above, there is not much problem when the thickness of the paper 7 is thin.
When the thickness of the paper 7 increases, the elastic force of the paper 7 increases, so that the paper 7 does not fit sufficiently along the platen 5 or the thermal head 4. If the paper 7 does not fully follow the thermal head 4, the thermal head 4 will only partially apply pressing force to the paper, and the characters will become thin in areas where the pressing force is insufficient. In other words, the characters become blurred. When the paper thickness is large as described above, there is a problem in that the thermal head and the paper come into poor contact due to the elastic force of the paper, resulting in a decrease in printing quality. SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems and provide a paper path device for a printer in which the print quality does not deteriorate even when the paper thickness is large and the elastic force of the paper is large. [Means for Solving the Problems] In order to achieve the above object, the present invention includes a feed roller that feeds paper by wrapping paper around its outer periphery, a pinch roller unit that presses the paper against the feed roller, and a pinch roller unit that presses the paper against the feed roller. The paper and the ink ribbon are sandwiched between a platen disposed facing the path of the paper sent out from the feed roller and the platen, which is located opposite the platen, and the paper and the ink ribbon are pressed while the paper and the ink ribbon are pressed. In a printer having a printing head that prints on paper, a paper holding section provided near the printing head bends a paper path on an extension line of the paper sandwiched between the platen and the printing head in the direction of the platen. The structure is as follows. [0006] According to the present invention, as described above, the paper path on the extension line of the paper sandwiched between the platen and the printing head is guided by the paper presser provided near the printing head. By bending in this direction, the contact between the printing head and the paper can be made uniform even when printing on paper with a large elastic force. [Embodiment] An embodiment of the present invention will be described below. Note that the same reference numerals are used for the same constituent members as those shown in the conventional example described above. In Figure 1, the thermal head 4 is connected to the platen 5.
The state in which the paper 7 and the ink ribbon 6a are sandwiched and pressed between them is shown. FIG. 2 is a side view of FIG. 1. As shown in the figure, in the embodiment of the present invention, a part of the paper presser section 20 has an overhang section 20a. As shown in FIG. 2, the paper 7 is fed by a feed roller 8 rotating in the direction of arrow A while being sandwiched between the thermal head 4 and the platen 5. Try to head in the direction of arrow C. In the embodiment of the present invention, by providing the overhang portion 20a as described above, the passage of the paper 7 is bent in the direction of the solid line shown in the drawing against the elastic force of the paper 7. In other words, the paper path is forcibly bent in the direction of the platen 5. By doing this, even if the paper 7 has a large elastic force, the thermal head 4 can exert a sufficient pressing force on the paper 7.
Good print quality can be obtained. [0008] In the above explanation, an example of a printer using a thermal head has been explained, but the present invention is not limited to a printer using a thermal head, but can also be applied to a printer using a dot printing head or the like. can also be used. [0009] As is clear from the embodiments described above, according to the present invention, the paper presser provided near the printing head allows the paper to be held between the platen and the printing head on an extended line. By bending the paper path in the direction of the platen, even when printing on paper with a large elastic force, the printing head and the paper come into uniform contact and good print quality can be ensured.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of a paper passage device of a printer provided with a paper presser according to an embodiment of the present invention.

[Figure 2] Side sectional view of Figure 1

[Figure 3] Side cross-sectional view of the paper path device of a conventional printer when not printing

[Fig. 4] Side cross-sectional view of the paper path device of a conventional printer during printing

[Explanation of symbols]

4 Thermal head (printing head) 5
Platen 7 Paper (print paper) 8 Feed roller 9 Pinch roller unit 20 Paper presser

Claims (1)

[Claims] 1. A feed roller that feeds the paper by wrapping the paper around its outer periphery, a pinch roller unit that presses the paper against the feed roller, and a platen that is disposed facing the path of the paper sent out from the feed roller. , a printer having a printing head which occupies a position opposite to the platen, sandwiches the paper and the ink ribbon between the printer and the platen, and prints on the paper while pressing the paper and the ink ribbon, in the vicinity of the printing head; A paper path device for a printer, in which a paper path on an extension of the paper sandwiched between the platen and the printing head is bent in the direction of the platen by a paper presser provided in the printer.