JP5972063B2 - Thermal transfer printer - Google Patents

Description

  The present invention relates to a thermal transfer printer, and more particularly, to a thermal transfer printer that performs printing by pressing a thermal head against an ink ribbon.

  The thermal transfer type printer heats the ink ribbon ink with a wide thermal head to sublimate it, and transfers and fixes it to the receiving layer of a dedicated printing paper that is crimped to the ink ribbon between the platen roller and the thermal head. Do.

  In order to appropriately transfer the heat of the thermal head to the ink ribbon during printing, it is necessary that the thermal head and the platen roller are in close contact with each other. In general, in a thermal transfer type printer, the thermal head has a bent shape in order to improve the adhesion between the thermal head and the platen roller. The magnitude of this deflection is called flatness.

  Since the heat sink for radiating the heat generated by the thermal head is attached to the upper part of the thermal head, the thermal head can be bent by bending the heat sink.

  For example, in patent document 1, the device which makes a thermal head contact | adhere to a platen roller with a more uniform pressure is made | formed by installing a some spring in the back side of a heat sink.

Japanese Patent Laid-Open No. 9-290522

  In a thermal transfer printer, if the flatness of the thermal head is not appropriate, printing defects such as fading may occur. The cause of defective printing is the frictional force between the thermal head and the ink ribbon. In particular, if the distribution of frictional force in the main scanning direction (hereinafter simply referred to as frictional force distribution) is biased, Defects are likely to occur.

  The distribution of the friction force is a correlation between the distribution of the friction coefficient and the pressure distribution. Here, the pressure is the pressure of the thermal head against the ink ribbon and the printing paper.

  The distribution of the frictional force varies depending on, for example, the density distribution of the printed image, the environmental temperature, the type of media (ink ribbon, printing paper), and the like. For example, the friction coefficient distribution changes depending on the density distribution of the print image and the type of ink ribbon. Further, for example, the pressure distribution changes due to the change in the rigidity of the printing paper due to a change in the environmental temperature.

  Therefore, it is necessary to perform printing while changing the flatness of the thermal head in accordance with printing conditions such as the density distribution of the print image so that the distribution of the frictional force is not biased.

  However, in Patent Document 1 described above, since the flatness of the thermal head is fixed, the flatness of the thermal head cannot be adjusted according to printing conditions such as the density distribution of the printed image.

  SUMMARY An advantage of some aspects of the invention is to provide a thermal transfer printer capable of adjusting the flatness of a thermal head.

A thermal transfer printer according to the present invention is a thermal transfer printer that performs printing by pressing a thermal head against an ink ribbon, and includes a variable mechanism for variably adjusting the flatness of the thermal head. The flatness is adjusted according to the density distribution of the printed image.
A thermal transfer type printer according to the present invention is a thermal transfer type printer that performs printing by pressing a thermal head against an ink ribbon, and includes a variable mechanism for variably adjusting the flatness of the thermal head. The flatness of the head is adjusted according to a change in environmental temperature.
A thermal transfer type printer according to the present invention is a thermal transfer type printer that performs printing by pressing a thermal head against an ink ribbon, and includes a variable mechanism for variably adjusting the flatness of the thermal head. The flatness of the head is adjusted according to the type of printing paper and / or ink ribbon.

  The thermal transfer printer according to the present invention performs printing while automatically adjusting the flatness of the thermal head 2 appropriately even under printing conditions in which the frictional force distribution between the thermal head 2 and the ink ribbon 3 is biased. Thus, it is possible to reduce printing defects such as faintness and wrinkles of the printed matter.

1 is a diagram illustrating a configuration of a thermal transfer printer according to a first embodiment. FIG. 3 is a diagram showing a variable mechanism for flatness of the thermal head according to the first embodiment. FIG. 6 is a diagram illustrating the operation of the mechanism for changing the flatness of the thermal head according to the first embodiment. It is a figure which shows the printing defect of a printed matter.

<Embodiment 1>
FIG. 1 shows a configuration of a thermal transfer printer according to the present embodiment. In the thermal transfer printer according to the present embodiment, the ink ribbon 3 on which the color material is disposed is pressure-bonded to the dedicated print paper 4 while being heated by the thermal head 2, whereby the color material disposed on the ink ribbon 3 is printed on the print paper. 4 is printed.

  The ink ribbon 3 is wound around the supply-side ink bobbin 3a in a roll shape, and printing is performed while being wound around the take-up-side ink bobbin 3b. Generally, a protective layer for protecting the surface of cyan, magenta, and yellow color materials and printed matter is periodically arranged on the ink ribbon 3.

  Moreover, the printing paper 4 is wound around the paper bobbin 4a, and is pulled out of the paper bobbin by a capstan roller and a pinch roller (not shown), for example, and conveyed.

  FIG. 2 is a front view of the thermal head 2 and the heat sink 1. The configuration of a variable mechanism that variably adjusts the flatness of the thermal head 2 will be described with reference to FIG. As shown in FIG. 2, a heat sink 1 is attached to the top of the thermal head 2. A plurality of, for example, two nuts 7 are fixed to the upper portion of the heat sink 1 at a predetermined interval, and long screws 8 are attached along the scanning direction via the nuts 7. The end of the long screw 8 is connected to the rotating shaft of the stepping motor 9, and the long screw 8 can be rotated by driving the stepping motor 9. The rotation speed and rotation direction of the long screw 8, that is, the rotation speed and rotation direction of the stepping motor 9 are controlled by a pulse sensor (not shown).

  The operation of the variable mechanism will be described with reference to FIG. When the long screw 8 is rotated in a direction in which a force acts in a direction in which the interval between the nuts 7 is reduced, the upper portion of the heat sink 1 to which the nut 7 is fixed receives the force toward the inside. Accordingly, as shown in FIG. 3A, the heat sink 1 and the thermal head 2 are bent downward.

  On the other hand, when the long screw 8 is rotated in a direction in which a force acts in a direction in which the distance between the nuts 7 is increased, the upper portion of the heat sink 1 to which the nut 7 is fixed receives a force toward the outside. Therefore, as shown in FIG. 3B, the heat sink 1 and the thermal head 2 are bent upward.

  The thermal transfer type printer can be connected to, for example, an external PC via a predetermined interface (not shown), and image data of a print image is transmitted from the external PC. The thermal transfer printer according to the present embodiment also includes a memory (not shown) for storing information necessary for adjusting the flatness of the thermal head 2. Information stored in the memory will be described later.

<Printing action>
A basic printing operation of the thermal transfer printer according to the present embodiment will be described. First, the first color material of the ink ribbon 3 is cued, and the ink ribbon 3 and the printing paper 4 are pressure-bonded between the thermal head 2 and the platen roller 5. While the ink ribbon 3 and the printing paper 4 are conveyed with a constant tension, the ink ribbon 3 is heated with a thermal head, and transfer is performed line by line. At this time, the thermal head is heated based on the image data.

  When the transfer of the first color material is completed, the thermal head 2 and the platen roller 5 are separated from each other, and the printing paper is rewound to the printing start position. Further, the ink ribbon 3 is wound up to the cueing position of the second color material. In this state, the transfer of the second color material is performed in the same manner as the transfer of the first color material. When the transfer of all the color materials including the protective layer is completed, the printing paper 4 is cut at a predetermined position and discharged.

  The thermal transfer printer according to the present embodiment performs transfer while adjusting the flatness of the thermal head 2 using a variable mechanism when transferring each color material and protective layer. Adjustment of the flatness of the thermal head 2 is performed according to the density distribution of the print image. Hereinafter, adjustment of the flatness of the thermal head 2 according to the density distribution of the print image will be described.

<Adjustment of flatness according to density distribution of print image>
Generally, in a thermal transfer printer, if the flatness of the thermal head 2 is not appropriate, printing defects such as blurring and wrinkling may occur on the printed matter. The fading is that the pressure of the thermal head 2 is not normally transmitted to the ink ribbon 3 and the printing paper 4 during transfer, and the color of the printed matter is lost. For example, when the pressure is insufficient at both ends of the thermal head 2, blurring tends to occur at both ends of the printed matter.

  Further, when wrinkles occur in the ink ribbon 3 at the time of transfer, as shown in FIG. 4, streak-like print wrinkles occur in the printed matter.

  The cause of these printing defects is greatly related to the frictional force between the thermal head 2 and the ink ribbon 3, and the distribution of the frictional force in the main scanning direction is particularly important. The frictional force distribution is a correlation between the friction coefficient distribution and the pressure distribution. Here, the pressure distribution is a pressure distribution with respect to the ink ribbon 3 and the printing paper 4 of the thermal head 2. The distribution of the friction coefficient varies depending on the density distribution of the printed image. For example, a portion having a higher concentration than the other portion has a friction coefficient relatively larger than that of the other portion, resulting in a bias in the friction coefficient distribution, resulting in a bias in the friction force distribution. Printing defects are likely to occur.

  In order to solve this problem, the thermal transfer printer according to the present embodiment includes a variable mechanism for variably adjusting the flatness of the thermal head 2, and adjusts the flatness according to the density distribution of the print image.

  The optimum flatness of the thermal head 2 with respect to the density distribution of the printed image is examined in advance by experiments. For example, patterns of density distribution of various printed images, and control pulses corresponding to the rotation direction and the number of rotations of the stepping motor 9 for adjusting to the optimum flatness for the patterns (hereinafter simply referred to as control pulses). Is stored in the memory.

  When the thermal transfer type printer receives print image data from an external PC, the thermal transfer printer refers to the memory, selects a pattern closest to the density distribution of the received print image data, and based on a control pulse corresponding to the selected print image pattern. Transfer is performed while adjusting the flatness of the thermal head 2.

  Generally, the friction coefficient tends to increase in a portion where the density of the printed image is high. For example, when the density of the central portion of the print image is higher than both ends, the friction coefficient distribution is adjusted by adjusting the flatness so that the thermal head 2 is convex upward as shown in FIG. To make the print uniform.

  On the other hand, when the density of the central portion of the printed image is lower than both ends, the friction coefficient distribution is adjusted by adjusting the flatness so that the thermal head 2 is convex downward as shown in FIG. To make the print uniform.

  In the present embodiment, the flatness of the thermal head 2 is adjusted based on the data stored in advance in the memory provided in the thermal transfer printer. For example, the external PC storing similar data The flatness may be adjusted by performing communication.

  Although the long screw 8 is directly connected to the stepping motor 9 in the present embodiment, a configuration in which a worm gear or the like is interposed between the long screw 8 and the stepping motor 9 may be used.

<Effect>
The thermal transfer type printer according to the present embodiment is a thermal transfer type printer that performs printing by pressing the thermal head 2 against the ink ribbon 3, and includes a variable mechanism for variably adjusting the flatness of the thermal head 2. To do.

  Therefore, even if the distribution of frictional force between the thermal head 2 and the ink ribbon 3 is biased depending on printing conditions, printing is performed by automatically adjusting the flatness of the thermal head 2 appropriately. It is possible to reduce printing defects such as blurring or wrinkling of objects.

  In the thermal transfer printer according to the present embodiment, the variable mechanism adjusts the flatness of the thermal head 2 according to the density change of the print image.

  Therefore, even if the density distribution of the print image is biased, printing is performed while adjusting the flatness of the thermal head 2 in accordance with the density distribution of the print image. It is possible to reduce defects.

<Embodiment 2>
The thermal transfer printer according to the present embodiment further includes a temperature sensor for measuring the environmental temperature in addition to the thermal transfer printer described in the first embodiment. Since other configurations are the same as those of the first embodiment, description thereof is omitted. In addition, it is good also as a structure which acquires the information of environmental temperature from the external apparatus connected via an interface instead of providing a temperature sensor.

  As described in the first embodiment, generally, when the thermal head 2 has an inappropriate flatness, a print defect such as faintness or wrinkle may occur on the print. The cause of the printing failure is an uneven distribution of frictional force between the thermal head 2 and the ink ribbon 3 in the main scanning direction. The frictional force distribution is a correlation between the friction coefficient distribution and the pressure distribution.

  When the environmental temperature changes, the rigidity of the printing paper 4 changes. Therefore, when the transfer is performed, the pressure distribution on the ink ribbon 3 and the printing paper 4 of the thermal head 2 changes. As a result, the frictional force distribution changes. . For example, since the printing paper 4 becomes soft in a high temperature environment, the pressure distribution on the printing paper 4 of the thermal head 2 is partially increased, and printing wrinkles are likely to occur. On the other hand, since the printing paper 4 becomes hard in a low temperature environment, the pressure distribution on the printing paper 4 is partially reduced and blurring tends to occur.

  In order to solve this problem, the thermal transfer printer according to the present embodiment includes a variable mechanism for variably adjusting the flatness of the thermal head 2 and adjusts the flatness according to changes in the environmental temperature.

  The thermal transfer printer in this embodiment includes a memory as in the first embodiment. The optimum flatness of the thermal head 2 with respect to the environmental temperature is examined in advance by experiments. The memory stores an environmental temperature and a control pulse for adjusting the flatness optimal to the environmental temperature.

  The thermal transfer printer according to the present embodiment acquires an environmental temperature from a temperature sensor, and performs transfer while adjusting the flatness of the thermal head 2 based on a control pulse stored in the memory and corresponding to the acquired environmental temperature. Do.

<Effect>
In the thermal transfer printer according to the present embodiment, the variable mechanism that adjusts the flatness of the thermal head 2 adjusts the flatness of the thermal head 2 according to changes in the temperature environment.

  Therefore, even when the environmental temperature changes and the pressure distribution is biased, and as a result, the frictional force distribution is biased, printing is performed while adjusting the flatness of the thermal head 2 according to the environmental temperature. Therefore, it is possible to reduce printing defects such as blurring and wrinkling of the printed material.

<Embodiment 3>
The thermal transfer printer according to the present embodiment performs printing while adjusting the flatness of the thermal head in accordance with the type of ink ribbon and the type of printing paper.

  A conventional general method is used as a method for discriminating the type of media. For example, an IC tag storing information such as the type of media is attached to a predetermined portion of the media, and the type of the media is determined by reading this with a predetermined sensor. Further, a method in which the user manually inputs the media type from the interface of the thermal transfer printer, a method in which the user inputs the media type from an external PC connected to the printer, and the like can be considered.

  Other configurations of the thermal transfer type printer in the present embodiment are the same as those in the first embodiment, and thus description thereof is omitted.

  As described in the first embodiment, generally, in a thermal transfer type printer, if the flatness of the thermal head 2 is not appropriate, a print defect such as blurring or wrinkling may occur on a printed matter. The cause of the printing failure is, in particular, an uneven distribution of frictional force between the thermal head 2 and the ink ribbon 3 in the main scanning direction. The frictional force distribution is a correlation between the friction coefficient distribution and the pressure distribution.

  When the type of the ink ribbon 3 changes, the friction coefficient distribution changes for each of the cyan, magenta, and yellow color materials. Further, when the type of the printing paper 4 changes, the pressure distribution changes.

  In order to solve this problem, the thermal transfer printer according to the present embodiment includes a variable mechanism for variably adjusting the flatness of the thermal head 2, and is flat according to the type of the ink ribbon 3 and the type of the printing paper 4. Adjust the degree.

  The thermal transfer printer in this embodiment includes a memory as in the first embodiment. The optimum flatness of the thermal head 2 with respect to the types of the printing paper 4 and the ink ribbon 3 has been examined in advance by experiments. The memory stores the type of media and control pulses for adjusting the flatness optimal for the type of media.

  When performing printing, the thermal transfer printer according to the present embodiment acquires the media type by the above-described method, and stores the thermal head 2 based on the control pulse corresponding to the acquired media type stored in the memory. Transfer is performed while adjusting the flatness of the sheet.

<Effect>
The variable mechanism in the thermal transfer printer according to the present embodiment is characterized in that the flatness of the thermal head 2 is adjusted according to the types of the printing paper 4 and the ink ribbon 3.

  Therefore, even if the distribution of the frictional force is biased due to the printing paper 4 and the ink ribbon 3, the flatness of the thermal head 2 is adjusted according to the types of the printing paper 4 and the ink ribbon 3. However, since printing is performed, it is possible to reduce printing defects such as blurring and wrinkling of the printed material.

  In this embodiment, the flatness of the thermal head 2 is adjusted according to both types of the ink ribbon 3 and the printing paper 4, but the flatness is adjusted according to one of the types. You may go. Even in such a case, it is possible to reduce printing defects such as blurring and wrinkling of the printed material.

  It should be noted that the present invention can be freely combined with each other within the scope of the invention, and each embodiment can be appropriately modified or omitted.

  1 Heat sink, 2 Thermal head, 3 Ink ribbon, 3a Supply side ink bobbin, 3b Winding side ink bobbin, 4 Printing paper, 4a Paper bobbin, 5 Platen roller, 7 Nut, 8 Long screw, 9 Stepping motor.

Claims (3)

A thermal transfer printer that performs printing by pressing a thermal head against an ink ribbon,
A variable mechanism for variably adjusting the flatness of the thermal head ;
The variable mechanism adjusts the flatness of the thermal head according to a density distribution of a print image.
Thermal transfer printer. A thermal transfer printer that performs printing by pressing a thermal head against an ink ribbon,
A variable mechanism for variably adjusting the flatness of the thermal head;
The variable mechanism adjusts the flatness of the thermal head according to a change in environmental temperature ,
Thermal transfer type printer. A thermal transfer printer that performs printing by pressing a thermal head against an ink ribbon,
A variable mechanism for variably adjusting the flatness of the thermal head;
The variable mechanism adjusts the flatness of the thermal head in accordance with the type of printing paper and / or ink ribbon .
Thermal transfer type printer.

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