JPH0588957U - Thermal transfer printer - Google Patents

Abstract

(57) [Abstract] [Purpose] To obtain a wide print area by minimizing the margin on the trailing edge of cut paper in a thermal transfer printer. A thermal head cover guide surface 2a formed on the thermal head cover 2 faces a platen roller 7 and forms a print sheet conveyance path for returning the print sheet 3 to the sheet feed roller 6 side. The printing paper 3 has its rear end 3b printed just before the thermal head heating element 1a, and then the paper feed roller 6
Returned to the side.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a thermal transfer printer, and more particularly to a mechanism for enlarging a printing area when printing is performed a plurality of times by reciprocating a cut sheet.

[0002]

[Prior Art]

 Conventionally, as shown in FIG. 2, the guide roller 10 and the platen roller 7 sandwich the print sheet 3 and the ink sheet 4, and the thermal head body 1 and the platen roller 7 sandwich the print sheet 3 and the ink sheet 4 to generate heat from the thermal head. It has been generally used by those skilled in the art to use a mechanism in which the heat of the body 1a is transferred for printing, the ink sheet 4 is peeled off from the printing paper 3 at the peeling portion 1b of the thermal head, and the paper is ejected by the paper ejection roller 5.

[0003]

[Problems to be solved by the device]

 However, in the conventional structure, when the print sheet 3 is to be fed back and returned in multiple prints when performing multicolor printing, the rear end of the print sheet 3 is located closer to the discharge side than the guide roller 10. The print sheet 3 comes off between the guide roller 10 and the platen roller 7, breaks the ink sheet 4, or enters between the guide roller 10 and the thermal head body 1 to cause a paper jam. Therefore, in FIG. 2, there is a problem that an unprintable area on the rear side of the printing paper, that is, a blank space of 20 mm or more is generated on the circumference of the platen roller 7 at least as long as the length between A and B. It was

Therefore, an object of the present invention is to solve such a problem in the related art, and a thermal transfer method capable of performing printing without causing a paper jam when returning the printing paper at the time of printing a plurality of times and minimizing a margin. To get a printer.

[0005]

[Means for Solving the Problems]

 In order to solve the above problems, the present invention is a thermal transfer printer having a platen roller and a thermal head, in which a guide surface for guiding the printing paper and the ink sheet is formed on the surface of the thermal head facing the platen roller. The printing paper and ink sheet can run stably between the surface and the platen roller.

[0006]

[Action]

 As described above, since the formed guide surface guides the trailing edge of the printing paper and secures the traveling path of the printing paper, the trailing edge of the printing paper when the printing paper starts to return is If it is within the range, the printing paper can be returned without causing a paper jam. Therefore, the margin on the rear side of the printing paper can be minimized.

[0007]

【Example】

 An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a sectional view of an embodiment of the present invention. The printing paper 3 and the ink sheet 4 are sandwiched by the platen roller 7 and the thermal head body 1, and the printing paper 3 is sent to the paper ejection roller side by the rotation of the platen roller 7, the paper feed roller 6, and the paper ejection roller 5. These rollers are rotated by the driving force of a printing paper drive system (not shown). At the same time, the ink sheet 4 is sent to the take-up side ink sheet roll 4b side together with the print sheet 3 at the same speed as the print sheet 3 by the rotation of the supply side ink sheet roll 4a and the take-up side ink sheet roll 4b. These ink sheet rolls are rotated by the driving force of an ink sheet driving system (not shown). An image signal is sent to the thermal head main body 1 from a control circuit (not shown), and the thermal head heating element 1a transfers heat to the ink sheet 4 according to the image signal to print on the printing paper 3.

The thermal head cover 2 is generally provided as an integral part of the thermal head body 1 in order to protect electronic components (not shown) that process image signals mounted on the thermal head body 1. ing. The thermal head cover guide surface 2a forms a surface facing the platen roller 7, and the printing paper 3 and the ink sheet 4 run between the thermal head cover guide surface 2a and the platen roller 7.

Next, the movement of the printing paper 3 during printing will be described. The printing paper 3 is first sent out from a paper stocker (not shown), passes through the paper feed roller 6, and enters between the platen roller 7 and the thermal head cover guide surface 2a. After the leading edge 3a of the printing paper 3 passes through the thermal head heating element 1a, the thermal head heating element 1a generates heat according to the image signal and printing is started. In general, in the case of color printing, color printing is performed by using ink sheets of three colors such as yellow, magenta, and cyan (hereinafter referred to as Y, M, and C) and sequentially printing these three color inks. Is getting Hereinafter, the operation during color printing will be described continuously.

When the printing of the first color (for example, Y) is completed after the start of printing, the thermal head body 1 is moved up by a driving device (not shown) as shown by the broken line in FIG. Next, the printing paper 3 is returned to the paper feed roller 6 side by the reverse rotation of each roller. As described above, each roller is driven by the printing paper drive system (not shown), but it is possible to rotate forward and backward. Immediately before the printing paper 3 is returned, the trailing edge 3b of the printing paper is on the paper feed roller 6 side of the thermal head heating element 1a and between the platen roller 7 and the thermal head cover guide surface 2a.

This is because if the trailing edge 3b of the printing paper 3 is located closer to the paper discharge roller 5 than the heating element 1a, then there will be a problem that ink will be transferred to the platen roller 7. Further, when the print sheet 3 is returned, the ink sheet 4 is not returned and remains stopped. The trailing edge 3b of the printing paper 3 which has begun to be returned comes out of the thermal head cover guide surface 2a and is then sandwiched by the paper feed roller 6 until the leading edge 3a of the printing paper 3 comes just before the thermal head heating element 1a. Be done. At this time, the ink sheet 4 is wound on the winding-side ink sheet roll 4b to print the second color (for example, M) on the printing paper 3, and moves to a predetermined position corresponding to the thermal head and the platen roller.

After that, the thermal head main body 1 goes down to the state shown by the solid line in FIG. 1, and the printing paper 3 is sent again to the paper discharge roller 5 side to start printing the second color M. In this way, the printing paper is reciprocated twice, printed with the third color, and then ejected. The thermal head cover guide surface 2a may be formed by using the shape of the thermal head main body 1 instead of the method of changing the shape of the thermal head cover 2 as in this embodiment. It is also possible to attach another member having a guide surface to the thermal head body. When forming the guide surface, the printing paper 3 and the ink sheet 4 are formed so as to run smoothly. In particular, the ink sheet 4 is designed so as not to be broken by being sandwiched between the rear end 3b of the printing paper 3 and the thermal head cover guide surface 2a. Specifically, the gap between the thermal head cover guide surface 2a and the platen roller 7 is about 1 to 2 mm.

When the printing paper 3 is fed to the paper feed roller 6 side, the heating element 1 a and the thermal head cover guide surface 2 a are arranged so that the trailing edge 3 b of the printing paper comes to a position sandwiched by the paper feed rollers 6. In this embodiment, the length between the sheet feeding roller 6 and the end face is 20 mm, but the lower limit is 15 mm. The thermal head cover guide surface 2a follows the shape of the platen roller 7.

In this embodiment, color printing is performed by using YMC three color inks. However, when YMC and black four color inks are used, or one color ink is used even if color printing is not performed. It can be easily applied to printing multiple times to obtain density or gradation. It should be noted that, regardless of the length of the thermal head cover guide surface 2a, the blank space at the rear end of the printing paper is theoretically zero in the present invention, and in reality, there are variations in the parts dimensions, etc. There is.

Therefore, in the thermal transfer printer, any mechanism that prints a cut sheet a plurality of times is included in the scope of the present invention.

[0016]

[Effect of the device]

 As described above, the present invention provides the thermal head with the guide surface facing the platen roller, so that the print sheet breaks the ink sheet or the print sheet causes a paper jam between the thermal head and the platen roller. In addition, there is an effect that a wide printing area can be obtained by minimizing the margin on the trailing edge of the printing paper when printing multiple times.

[Brief description of drawings]

FIG. 1 is a sectional view of an embodiment of the present invention.

FIG. 2 is a cross-sectional view of a conventional structure.

[Explanation of symbols]

 1 Thermal Head Main Body 2 Thermal Head Cover 2a Thermal Head Cover Guide Surface 3 Printing Paper 4 Ink Sheet 5 Paper Ejection Roller 6 Paper Feed Roller 7 Platen Roller

Claims (1)

[Scope of utility model registration request] 1. A thermal transfer printer having a thermal head and a platen roller, characterized in that a guide surface for guiding printing paper is formed on a surface of the thermal head facing the platen roller.