JPH04368872A - Serial type thermal transfer printer - Google Patents

Abstract

PURPOSE:To stabilize the running of an ink ribbon by providing a means capable of changing the pressing angle of a thermal head to a ribbon cassette having an ink ribbon received therein at the time of printing. CONSTITUTION:By adjusting the gap quantity (x) between the guide shaft mounting hole 19 of a frame 7 and a guide shaft 12 by an adjusting screw 15, a carriage 11 is relatively moved with respect to the frame 7 and a platen 13 and the pressing angle theta at the time of printing of a thermal head 1 to a ribbon cassette 10 can be approximately adjusted. The guide shaft 20 is fixed to the frame 7 at both ends thereof to hold the carriage 11 to proper height and the hole 21 permitting the guide shaft 20 of the carriage 11 to pass is formed into a rectangular shape so as to be capable of smoothly moving the carriage 11 before and behind when the gap quantity (x) is adjusted. By approximately adjusting the pressing angle theta of the thermal head 1 to the ribbon cassette, the running of an ink ribbon 9 is stabilized.

Description

[Detailed description of the invention]

0001

[Field of Industrial Application] The present invention relates to a serial type thermal transfer printer, and in particular, to improving the running stability of the ink ribbon.
Regarding improving print quality.

0002

[Prior Art] In conventional serial type thermal transfer printers,
In particular, there is no mechanism that can adjust the pressing angle when printing with a thermal head on an ink ribbon or a ribbon cassette containing an ink ribbon, and the pressing angle is determined by a combination of several types of parts that contribute to the pressing angle. For this reason, the pressing angle existed with a certain degree of width depending on the component accuracy and assembly accuracy of several types of parts that contributed to the pressing angle. Variations in the pressing angle affect the pressure distribution between the thermal head and the printing paper, which can cause problems such as partially faded print, and the ink ribbon shifting up and down along the thermal head during printing, making the ink ribbon run unstable. This was a major cause of the problem.

[0003] To solve the problem of partially faded print caused by uneven pressure distribution between the thermal head and the printing paper, conventional serial type thermal transfer printers either use a platen with a self-aligning structure or use a relatively By using a cylindrical platen with a large diameter, uneven pressure distribution between the thermal head and the printing paper caused by variations in the pressing angle is alleviated.
This prevents the problem of partially faded print. In addition, to solve the problem of unstable ink ribbon running, we are considering manipulating the ink composition, which is closely related to print quality, to weaken the force that peels off the ink during ink transfer, at the expense of print quality. In order to stabilize the running of the ink ribbon, the supply diameter of the ink ribbon was reduced at the expense of running costs.

0004

[Problems to be Solved by the Invention] Conventionally, using a platen with a self-aligning structure or using a cylindrical platen with a relatively large diameter, thermal head and printing problems due to variations in the pressing angle have been avoided. In the method of alleviating the uneven pressure distribution between sheets and preventing the problem of partially faded print, if there is a large variation in the pressing angle, the thermal head,
It is impossible to completely eliminate the problem of partially faded print by alleviating uneven pressure distribution between printed sheets. In addition, with either method, the pressing angle of the thermal head during printing cannot be adjusted at all for ink ribbons or ribbon cassettes containing ink ribbons, and problems occur near the thermal head due to variations in the pressing angle. It is not possible to make adjustments to prevent the ink ribbon from sliding up or down, which is undesirable in terms of the running stability of the ink ribbon.

The present invention has been made in order to solve these drawbacks, and it is possible to prevent the above-mentioned ink ribbon from slipping up or down, stabilize the running of the ink ribbon, and improve the thermal head. The purpose of this method is to alleviate uneven pressure distribution between printing sheets and suppress negative effects on print quality.

[0006]

[Means for Solving the Problems] The serial type thermal transfer printer of the present invention prints on printing paper via an ink ribbon while moving a thermal head equipped with a plurality of heat generating elements in a digit direction. The present invention is characterized in that it includes means that can vary the pressing angle of the thermal head against a ribbon cassette containing the ink ribbon during printing.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a schematic diagram of one embodiment of a serial type thermal transfer printer according to the present invention. 1 is a thermal head, 2 is a head support plate provided for the purpose of supporting the thermal head 1 fixed to the back surface of the thermal head and promoting heat radiation of the thermal head 1, and 3 is a head support plate in which heat generating elements of the thermal head are arranged in a row. 7 is a frame, 9 is an ink ribbon with heat-melting ink applied to the surface of a film-like resin, 10 is a ribbon cassette, 11 is a carriage, 12,
Reference numeral 20 indicates a guide shaft provided for the purpose of guiding the movement of the carriage 11 in the digit direction, 13 indicates a platen, and 14 indicates printing paper.

During printing, the head support plate 2 rotates counterclockwise around the head support plate rotation axis 17 and falls to the front, and an appropriate pressing force is applied between the thermal head 1 and the platen 13 by the head pressure spring 18. At times other than printing, such as during paper feeding, the head support plate rotates clockwise around the rotating shaft 17, falls backward, and holds the printing paper 14 in a released state. The platen 13 is inclined to some extent to correspond to the pressing angle θ of the thermal head 1 against the ribbon cassette 10 during printing, so as to make the pressure distribution on the printing surface constant.

The ribbon cassette 10 includes a supply spool around which an unprinted ink ribbon 9 is wound, a take-up spool 4 that winds up a printed ink ribbon 9, and a plurality of winding spools provided for the purpose of guiding the ink ribbon 9. The ribbon guide roller 6 is composed of two ribbon guide rollers 6, and can be easily attached to and detached from the carriage 11.

The carriage 11 has a ribbon winding mechanism 5 that winds the printed ink ribbon 9 around the thermal head 1.
The thermal head 1 has a mechanism for moving the thermal head 1 in the front-back direction as described above, and has a hole whose cross section through which the guide shaft 12 passes is circular and whose diameter is the same as that of the guide shaft, and a cross section through which the guide shaft 20 passes through which one side is the same as the guide shaft 20. A rectangular hole with a large diameter is provided. The carriage 11 formed as described above is the guide shaft 1
The ink ribbon 9 is pulled out from the supply spool by being supported and guided by the ink ribbons 2 and 20 and driven in the digit direction.
The ink is supplied to the thermal head 1, melted by the heating element 2 on the thermal head 1, transferred to the printing paper 14, and then wound onto the take-up spool 4.

The guide shaft 12 fixing portion of the frame 7 has a rectangular guide shaft mounting hole 1 with one side having a larger diameter than the guide shaft 11.
9 is provided, and the guide shaft 12 is fixed to the guide shaft mounting hole 19 of the frame 7 by pressing both ends of the guide shaft 12 on one side with a spring 16 and on the other side with an adjustment screw 15. Adjustment screw 15 aligns guide shaft mounting hole 19 of frame 7 with guide shaft 1.
By adjusting the gap amount x in step 2, the carriage 11 moves relative to the frame 7 and platen 13,
The pressing angle θ of the thermal head 1 against the ribbon cassette 10 during printing can be conveniently adjusted. The guide shaft 20 has both ends fixed to the frame 7 to hold the carriage 7 at an appropriate height, and the hole 21 of the carriage 11 through which the guide shaft 20 passes allows the carriage 11 to move smoothly when adjusting the clearance x as described above. It is shaped like a rectangle so that it can be moved forward or backward.

Generally, when printing is performed with the thermal head 1 tilted forward with respect to the ribbon cassette 10, the ink ribbon 9 tends to slide up along the thermal head 1 in the direction of arrow h. Further, when printing is performed with the thermal head 1 tilted rearward with respect to the ribbon cassette 10, the ink ribbon 9 tends to slide down along the thermal head 1 in the direction of arrow i.

FIG. 2 is a schematic diagram of an embodiment of the present invention showing the pressing angle θ of the thermal head 1 with respect to the ribbon cassette 10 and the running state of the ink ribbon 9. 9a shows the trajectory of printing on the ink ribbon 9 when printing is performed with the thermal head 1 tilted too far backward relative to the ribbon cassette 10, and the ink ribbon 9 slides down during printing.
It is detached from the heat generating part 2, causing a fatal defect in which printing is no longer possible in the middle of the printing digit, a so-called missing character.

9c shows the trajectory of printing on the ink ribbon 9 when printing is performed with the thermal head 1 tilted too far forward relative to the ribbon cassette 10. In particular, the ink ribbon 9, which has a width more than twice the length in the longitudinal direction of the heat generating part 2 of the thermal head 1, and the ribbon cassette 10 can be installed by reversing them, and the upper half and lower half of the ink ribbon 9 can be installed in the outward and return directions, respectively. In a serial type thermal transfer printer capable of reciprocating printing, which is configured to print using ink of If the virgin ink surface of the lower half used on the return trip is invaded, when printing on the return trip, it may overlap with the print trajectory on the outbound trip, resulting in a loss of print quality such as partial loss or thinning of the print. be.

9b shows the locus of printing on the ink ribbon 9 when printing is performed with the pressing angle θ of the thermal head 1 applied to the ribbon cassette 10 appropriately adjusted.

When the running of the ink ribbon 9 is unstable like the ink ribbons 9a and 9c, serial type thermal transfer which does not have a mechanism for adjusting the pressing angle θ of the thermal head 1 during printing with respect to the ribbon cassette 10 as in the past is used. For printers,
It is difficult to easily stabilize the running of the ink ribbon 9.

In general, the ink ribbon 9 near the thermal head 1 has various effects due to changes in the winding torque, changes in the frictional force between the printing paper 14, the ink ribbon 9, and the thermal head 1 due to changes in the environmental temperature, etc. However, by appropriately adjusting the pressing angle θ of the thermal head 1 against the ribbon cassette 10, the running behavior of the ink ribbon 9 can be stabilized. .

Furthermore, by appropriately adjusting the pressing angle θ of the thermal head 1 with respect to the ribbon cassette 10, the pressure distribution between the thermal head 1 and the printing paper 14 can be corrected, and the problem of partially faded print can be eliminated.

In this embodiment, a mechanism for adjusting the pressing angle θ of the thermal head 1 during printing with respect to the ribbon cassette 10 is provided at the joint between the frame 7 and the guide shaft 11. , a mechanism is provided on either of the platen support plates 8 to conveniently adjust the relative positional relationship in the pressing direction of the thermal head 1 during printing, and the pressing angle θ of the thermal head 1 during printing with respect to the ribbon cassette 10 is adjusted. You can.

[0020]

As described above, according to the present invention, a mechanism for appropriately adjusting the pressing angle of the thermal head against the ribbon cassette is provided in a part of the serial type thermal transfer printer, and the pressing angle of the thermal head against the ribbon cassette can be adjusted appropriately. Through adjustment, it is possible to stabilize the running of the ink ribbon, correct the pressure distribution between the thermal head and the printing paper, and eliminate the problem of partially faded print. In particular, when it comes to increasing the printing speed of serial type thermal transfer printers, stabilizing the running of the ink ribbon is as important as thermal control of the thermal head. It has an excellent effect on stabilizing the running of the ink ribbon.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram showing one embodiment of the invention.

FIG. 2 is a schematic diagram illustrating an embodiment of the invention.

[Explanation of symbols]

1 Thermal head 9 Ink ribbon 10 Ribbon cassette 11 Carriage 13 Platen 14 Printing paper 18 Head pressure spring

Claims (1)

[Claims] 1. In a serial type thermal transfer printer that prints on printing paper via an ink ribbon while moving a thermal head disposed with a plurality of heat generating elements in a digit direction, a ribbon that stores the ink ribbon during printing. A serial type thermal transfer printer, comprising means for varying the pressing angle of the thermal head relative to the cassette.