JP2002052774A - Thermal transfer printer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable high-quality printing by preventing wrinkling to an ink ribbon and preventing printing failures caused by the wrinkles. SOLUTION: A coating layer 203 of a material having a high friction coefficient is formed to a surface of a guide roller 201 of the discharge side. The coating layer 203 generates a high frictional force to the ink ribbon 120. The frictional force exceeds a force of moving the ink ribbon 120 in a breadth direction. Therefore, even when the ink ribbon 120 extends at separate positions in the breadth direction, the guide roller 201 prevents the ink ribbon 120 from sliding in the breadth direction, thereby suppressing wrinkling.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermal transfer printer for transferring the dye of an ink ribbon to printing paper by the heat of a thermal head.

[0002]

2. Description of the Related Art FIG. 5 is a diagram showing a schematic configuration of a printing mechanism of a printer 100. The printer 100 is generally constituted by a paper feed mechanism 110, an ink ribbon 120, a thermal head 130, and a paper cassette 140. The printer 100 is driven by image data from a personal computer (hereinafter, referred to as a personal computer) not shown.

The paper feed mechanism 110 includes a thermal head 13
0, a paper feed roller 111 and a pinch roller 112 which are divided into a paper feed side and a discharge side and are disposed on the paper feed side; a platen roller 113 which is disposed at a position facing the thermal head 130; Discharge roller 11 arranged in
4 and a pinch roller 115. The paper feed mechanism 110 feeds a printing paper 141, which will be described later, through a space between the paper feed roller 111 and the pinch roller 112, a space between the thermal head 130 and the platen roller 113, and a space between the paper discharge roller 114 and the pinch roller 115. Convey sequentially. Further, the sheet feeding roller 111 and the platen roller 1
13 and the paper discharge roller 114 are driven to rotate by a driving source (not shown) such as a stepping motor.
By driving this motor, the paper feed roller 11
1. When the platen roller 113 and the paper discharge roller 114 rotate clockwise, the print paper 141 is transported in the feed direction F, while when rotated counterclockwise, the print paper 141 is transported in the return direction R.

[0004] The ink ribbon 120 is made of the base film 1.
Both ends of the supply roll 20a are the supply roll 121 and the take-up roll 1
22. This winding roll 122
Is rotated clockwise by a drive source (not shown) such as a DC motor to wind up the ink ribbon 120. Thus, the ink ribbon 120 is transported in the feed direction f. As shown in FIG. 6, the structure of the ink ribbon 120 is such that a thin base film 120a and a Y (yellow) dye, M
Dye layers 120Y, 120M, and 120C to which a dye is applied repeatedly in the order of a (magenta) dye and a C (cyan) dye.

Further, as the dye of the ink ribbon 120, a dye which can be sublimated by heat is used. The printer 100 using the ink ribbon 120 can perform gradation printing in which the print density level is changed by adjusting the temperature of the thermal head 130, and the printing paper 141.
Will be subjected to high-quality color printing.

[0006] Similarly to the paper feed mechanism 110, the ink ribbon 120 is divided into a supply side and a discharge side with the thermal head 130 as a boundary, and the thermal head 130 and the supply side roll 12 are separated.
1, a supply side guide roller 123 is disposed between the thermal head 130 and the take-up roll 122, and a discharge side guide roller 124 is disposed between the thermal head 130 and the take-up roll 122.

The thermal head 130 has a plurality of heating elements (both not shown) arranged in a row on a substrate.
The platen roller 113 is separated or pressed against the platen roller 113 by a lifting mechanism (not shown). The thermal head 13
In the vicinity of 0, a peeling plate 131 is provided. The release plate 131 presses the ink ribbon 120 against the printing paper 141 when the dye is thermally transferred to the printing paper 141.

The paper cassette 140 has a fixed form (for example, A
4, A5, etc.). The printing paper 141 is taken out one by one by a sheet feeder (not shown) and is conveyed through a paper conveyance path 116. In the printer 100, color printing is performed on the printing paper 141 by sequentially overlapping and transferring the yellow, magenta, and cyan dyes attached to the ink ribbon 120 onto the printing paper 141.

[0009]

By the way, the ink ribbon 120 is formed of a very thin sheet material of several μm in order to reduce the running cost of the printer and reduce the size (reduction of the space occupied by the roll). ing. For this reason, wrinkles W may be generated on the ink ribbon 120 as shown in FIG.

The wrinkles W generated on the ink ribbon 120 may extend to a dye layer that has not been thermally transferred. In this case, in the portion of the dye layer folded by the wrinkles W, the heat from the thermal head 130 cannot be reliably transmitted to the dye, and a transfer failure of the dye occurs to cause a printing failure.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and eliminates wrinkles generated on an ink ribbon to prevent printing defects caused by the wrinkles and achieve high quality printing. It is an object of the present invention to provide a thermal transfer printer capable of realizing the following.

[0012]

Means for Solving the Problems The present inventors have studied the causes of wrinkles W generated on the ink ribbon 120. In this examination process, the first focus is on the fact that wrinkles W frequently occur when high-density printing is performed (for example, when solid printing with 255 gradations of M colors is performed). Here, the ink ribbon 120 receives the heat of the thermal head 130, and the extension of the dye layer 120M is remarkably exhibited. In this case, the ink ribbon 12 is
When the ink layer 120M is pulled at a constant speed, that is, at a constant force, a speed difference is generated between the portion of the dye layer 120M that is extended by heat and the portion that is not extended outside. A force that pulls in the width direction and a force that moves from the outside to the inside in the width direction are generated. The force to move in the width direction resists the frictional force between the ink ribbon 120 and the guide roller 124, and the ink ribbon 1
It is presumed that wrinkles W are generated by moving both sides of 20 toward the center.

Next, the present inventors have focused on the second point that the ink wound around the winding roll 122 is smaller than when the ink ribbon 120 wound around the winding roll 122 is small. The fact is that wrinkles W frequently occur when the number of ribbons 120 is large. Here, take-up roll 1
When the amount of the ink ribbon 120 wound around the roll 22 is small, the contact area between the ink ribbon 120 and the guide roller 124 is secured to some extent because the diameter of the winding roll 122 is small. On the other hand, the winding roll 12
In a state where the number of the ink ribbons 120 wound around 2 is large, the diameter of the winding roll 122 is large, and the contact area between the ink ribbon 120 and the guide roller 124 is small. As described above, when the number of the ink ribbons 120 wound around the winding roll 122 increases, the contact area between the ink ribbon 120 and the guide roller 124 decreases, and the frictional force decreases. It is estimated that the ink ribbon 120 slides on the guide roller 124 in the width direction and wrinkles W occur due to the decrease in the frictional force.

Thus, the inventors of the present application have found that the frictional force generated between the guide roller 124 and the ink ribbon 120 is reduced, so that the ink ribbon 120 slides in the width direction of the guide roller 124 and wrinkles W are generated. , Came to the conclusion.

Therefore, in order to solve the above-mentioned problem, the invention according to claim 1 is a guide roller for guiding the transferred ink ribbon in a thermal transfer printer for transferring the dye of the ink ribbon to printing paper by the heat of a thermal head. Wherein the surface of the guide roller is made of a material having a high friction coefficient.

According to a second aspect of the present invention, there is provided a thermal transfer printer for transferring a dye of an ink ribbon to printing paper by the heat of a thermal head, comprising a guide roller for guiding the transferred ink ribbon, wherein the guide roller is provided with the ink roller. It is characterized in that a frictional force for restricting the movement of the ribbon in the width direction is generated between the ribbon and the ink ribbon.

According to a third aspect of the present invention, in the thermal transfer printer according to the second aspect, the guide roller obtains the frictional force by securing a contact area between the guide roller and the ink ribbon. .

According to a fourth aspect of the present invention, in the thermal transfer printer according to the second aspect, the guide roller obtains the frictional force by securing a winding center angle around which the ink ribbon is wound. And

[0019]

DESCRIPTION OF THE PREFERRED EMBODIMENTS <1> First Embodiment A first embodiment according to the present invention will be described below with reference to the drawings. This embodiment shows one embodiment of the present invention, and can be arbitrarily changed without departing from the gist of the present invention. In the present embodiment, the same reference numerals are given to the same components as those of the above-described conventional technology, and the description thereof will be omitted.

<1-1> Features of the First Embodiment A feature of the first embodiment is that the surface of a discharge-side guide roller for guiding the ink ribbon 120 is covered with a coating layer made of a material having a high friction coefficient. It is in.

Here, as shown in FIG. 1, the discharge side guide roller 201 has a roller shaft 202 made of a rigid body such as metal.
And a coating layer 203 formed of a material having a high coefficient of friction and coated on the roller shaft 202.
The coating layer 203 includes a rubber coating or a shrink tube made of polyolefin or the like. Further, the entirety of the discharge side guide roller 124 may be a rubber roller formed of rubber.

<1-2> Arrangement Relationship between Discharge Side Guide Roller 201 and Winding Roll 122 and Wrapping Center Angle Next, based on FIG. Next, the winding center angle (wrapping center angle) of the discharge guide roller 124 will be described. The diameter dimension of the discharge side guide roller 201 is as follows.
The diameter dimension d is substantially the same as the guide roller 124 of the prior art.
(For example, about 8.0 mm). In the present embodiment, the central axis of the discharge-side guide roller 201 (hereinafter, referred to as the guide roller 201) is disposed at substantially the same height as the central axis of the take-up roll 122, similarly to the related art. The center angle of the guide roller 201 around the ink ribbon 120 is b1 when the number of the ink ribbons 120 wound around the winding roll 122 is small and the diameter of the winding roll 122 is small (dotted line). . Further, when a large number of ink ribbons 120 are wound on the winding roll 122 and the diameter of the winding roll 122 is large (two-dot chain line), the winding center angle is b2 (b2 <b1).
Further, the frictional force between the guide roller 201 and the ink ribbon 120 is calculated by the following equation. Friction force = (πd · b / 360) × L × ρ × α where d: diameter of guide roller b: center angle of winding L: width of ink ribbon ρ: coefficient of friction α: coefficient

Here, in the parentheses in the formula, the guide roller 2
11 shows the length of the arc where the ink ribbon 120 contacts the ink ribbon 120.

<1-3> Operation and Effect of First Embodiment In the present embodiment, the surface of the guide roller 201 is formed of the coating layer 203 having a high friction coefficient. As a result, the frictional force generated between the guide roller 201 and the ink ribbon 120 is larger than the frictional force according to the related art, as is apparent from the equation (1).

As described above, the ink ribbon 120 receives the heat of the thermal head 130, and
When the ink ribbon 120 is pulled by the take-up roll 122 in a case where there is a portion that partially extends in the width direction and a portion that does not extend, the length of the ink ribbon 120 is A pulling force in the direction and a force trying to move in the width direction act. Since the guide roller 201 according to the present embodiment has the coating layer 203 formed on its surface, a high frictional force is generated between the guide roller 201 and the ink ribbon 120. This frictional force exceeds the force of moving in the width direction at each position in the width direction of the ink ribbon 120, and suppresses the ink ribbon 120 from sliding in the width direction on the guide roller 201. Thereby, wrinkles generated on the ink ribbon 120 can be eliminated. Therefore, by eliminating wrinkles that have conventionally occurred on the ink ribbon 120, the printer 100 according to the present embodiment can eliminate print defects due to wrinkles and realize high-quality color printing.

<2> Second Embodiment Next, a second embodiment according to the present invention will be described. <2-1> Features of the Second Embodiment The features of the second embodiment are that the diameter dimension is d1 (d1> d) like the discharge side guide roller 301 shown in FIG.
(For example, d1 = about 10.0 mm).

<2-2> Arrangement Relationship between Discharge Side Guide Roller 301 and Winding Roll 122 and Wrapping Center Angle Based on FIG. Roller 12
The winding center angle (wrapping center angle) of No. 4 will be described.
In the present embodiment, the center axis of the guide roller 301 is disposed at substantially the same height as the center axis of the winding roll 122. However, the diameter of the guide roller 301 is d1 larger than the diameter d of the guide roller 201 according to the first embodiment. Therefore, the ink ribbon 12
The winding center angle of the guide roller 301 with respect to 0 is b3 when the number of the ink ribbons 120 wound around the winding roll 122 is small and the diameter of the winding roll 122 is small (dotted line). In addition, the ink ribbon 120 wound around the winding roll 122 is large,
When the diameter of 2 is large (two-dot chain line), the winding center angle is b4 (b3 <b4). Here, in the parentheses in the formula 1, the diameter is set to d1 larger than d to secure the contact area and increase the frictional force.

As a result, the guide roller 301 according to the present embodiment has a large diameter dimension d1 (d1> d), and thus secures a frictional force with the ink ribbon 120.
This frictional force is superior to the force of moving the ink ribbon 120 in the width direction at each position in the width direction of the ink ribbon 120, and prevents the ink roller 120 from slipping in the width direction with respect to the guide roller 201, thereby preventing wrinkles from occurring. Can be.

<3> Modified Example <3-1> Modified Example 1 In the above embodiments, the guide roller and the ink ribbon 12
In the first embodiment, the surface of the guide roller 201 is formed of the coating layer 203 in order to secure a frictional force between 0 and 0.
In the second embodiment, the diameter of the guide roller 301 is increased to d1. The present invention is not limited to this, and may have another configuration in which the arc formed by the winding center angle b is increased. For example, as shown in FIG.
Is higher than the center axis of the winding roll 122 by a dimension h.
It is also possible to lengthen the arc by arranging it at a higher position. That is, the winding center angle of the guide roller 124 ′ with respect to the ink ribbon 120 is
The ink ribbon 120 wound around 22 is small,
When the diameter of the winding roll 122 is small (dotted line), b5 is set. In addition, when the ink ribbon 120 wound around the winding roll 122 is large and the diameter of the winding roll 122 is large (two-dot chain line), the winding center angle is b6.
(B6 <b5). This winding center angle b5, b6
Is larger than the winding center angles b1 and b2 according to the first embodiment, so that the frictional force generated between the guide roller 124 'and the ink ribbon 120 is increased. This makes it possible to eliminate wrinkles generated on the ink ribbon 120.

<3-2> Modification 2 As described above, a frictional force for preventing the ink ribbon 120 from sliding in the width direction is generated between the ink ribbon 120 and the guide roller. , The diameter dimension d, and the winding center angle b were individually changed. According to the present invention, the guide rollers may be formed by combining each of them.

<3-3> Modification 3 In the printer 100 according to the above-described embodiment, color printing using three colors of Y, M, and C has been described as an example. Even in color printing, the present invention can be applied to black and white printing using only black.

[0032]

As described above, in the thermal transfer printer according to the present invention, the frictional force generated between the guide roller and the ink ribbon exceeds the force of the ink ribbon moving in the width direction. This prevents the ink ribbon from slipping on the guide roller in the width direction and suppresses wrinkles. Thereby, printing defects caused by wrinkles are reduced, and high-quality printing is realized.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a guide roller used in a first embodiment of the present invention.

FIG. 2 is an explanatory diagram showing a winding center angle of a discharge-side guide roller according to the embodiment.

FIG. 3 is an explanatory diagram showing a winding center angle of a discharge-side guide roller according to a second embodiment.

FIG. 4 is an explanatory diagram illustrating a winding center angle of a discharge-side guide roller according to a modified example.

FIG. 5 is a configuration diagram illustrating a main part of a printer according to the related art.

FIG. 6 is a plan view showing an ink ribbon used in the related art.

FIG. 7 is a perspective view showing a main part of a conventional printer.

[Explanation of symbols]

 REFERENCE SIGNS LIST 100 printer 120 ink ribbon 122 take-up roll 130 thermal head 141 printing paper 201, 301, 124 'discharge guide roller 203 coating layer

Claims (4)

[Claims] 1. A thermal transfer printer for transferring a dye of an ink ribbon to printing paper by the heat of a thermal head, comprising a guide roller for guiding the transferred ink ribbon, wherein the surface of the guide roller is made of a material having a high friction coefficient. A thermal transfer printer, comprising: 2. A thermal transfer printer for transferring a dye of an ink ribbon to printing paper by heat of a thermal head, comprising a guide roller for guiding the transferred ink ribbon, wherein the guide roller moves in a width direction of the ink ribbon. A thermal transfer printer for generating a frictional force between the ink ribbon and the ink ribbon, the frictional force restricting the ink transfer. 3. The thermal transfer printer according to claim 2, wherein the guide roller obtains the frictional force by securing a contact area between the guide roller and the ink ribbon. 4. The thermal transfer printer according to claim 2, wherein the guide roller obtains the frictional force by securing a winding center angle around which the ink ribbon is wound.