JPH01301268A - Thermal transfer recording device - Google Patents

Abstract

PURPOSE:To spread the degree of freedom of the selection of the material of a thermal transfer medium, a medium to be recorded, etc. while enabling recording having a high picture grade by carrying the thermal transfer medium so that the movement of the thermal transfer medium to a recording head is made slightly smaller than that of the medium to be recorded. CONSTITUTION:An ink ribbon 2 carried in the direction of the arrow A by a carrying means 9 with the shifting of a carriage 3 is wound on a take-up reel 1c while being given a constant forward tension by the drive of a winding motor and the action of a friction latch. The ratio of each gear 9d to 9f is set so as to be a value of 93% of the speed of travel of the carriage 3 to 100% so that the rotational peripheral speed of a carrying roller 9a conveying the ink ribbon 2 is made slightly slower than the speed of travel of the carriage 3 at that time. It is preferable that the carrying means 9 is mounted on the carrying stream side of the ink ribbon 2 upper than a recording head 4.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a thermal transfer recording apparatus that performs predetermined recording on a recording medium by selectively heating the thermal transfer medium with a recording head.

<Prior Art> Today, various types of writing devices are used as output devices such as word processors and electronic typewriters. Devices have been developed and put into practical use, and a typical example is a thermal transfer recording device.

In this recording device, a recording head presses a platen through an ink sheet and a recording sheet, and in the case of a serial type, the recording head is made to run, and in the case of a line type, the ink sheet and recording sheet are conveyed, and this In synchronization with this, the recording head selectively heats the ink sheet and transfers and records the molten ink onto the recording sheet.

When performing printing with the above-mentioned devices, there are devices in which the relative moving speed of the ink sheet is significantly smaller (for example, about 10 to 30%) than the relative moving speed of the printing sheet with respect to the print head. This has the advantage that the amount of sheets consumed can be significantly reduced.

However, when the above structure is adopted, slip occurs between the ink sheet and the recording sheet, which may disturb the transferred image and cause background stains on the recording sheet, so it is not put into practical use very often.

Conventionally, therefore, the tension applied to the ink sheet is generally adjusted so that no slip occurs between the ink sheet and the recording sheet due to the frictional force between the two, that is, the relative speed difference becomes zero.

<Problems to be Solved by the Invention> However, the friction coefficient of the ink sheet and recording sheet changes depending on environmental conditions such as temperature and humidity, and the mechanism for applying tension to the ink sheet also uses Fj friction force. Similarly, its characteristics change depending on environmental conditions. Therefore, in order to eliminate the relative speed difference between the two and completely prevent slipping, the materials of the ink sheet and recording sheet must be selected, and the tension applied to the ink sheet must also be finely adjusted. There were issues such as the need for

SUMMARY OF THE INVENTION An object of the present invention is to provide a thermal transfer recording apparatus that solves the above-mentioned problems, expands the degree of freedom in selecting materials for thermal transfer media, recording media, etc., and is capable of recording images with high quality.

<Means for Solving the Problems> The present invention has found that the best image quality is not necessarily obtained when the relative speed difference between the thermal transfer medium and the recording medium with respect to the recording head is reduced to zero during recording. The means for solving the problem is as follows: a recording head presses a thermal transfer medium and a recording medium, and the recording head and the thermal transfer medium and recording medium are moved relative to each other. In a thermal transfer recording device that performs recording, a conveying means for conveying the thermal transfer medium is provided such that the amount of movement of the thermal transfer medium relative to the recording head is slightly smaller than the amount of movement of the recording medium relative to the recording head. It is characterized by its composition.

Moreover, as a more preferable means, the conveyance means is provided upstream of the recording head in the direction of movement of the thermal transfer medium.

Effect> When recording is performed using the apparatus configured as described above, when the thermal transfer medium is heated by the recording head, the thermal transfer medium momentarily stretches slightly due to the heating, and furthermore, the ink on the thermal transfer medium melts or softens due to the heating. However, since the amount of movement of the thermal transfer medium with respect to the recording head is slightly smaller than that of the recording medium, stress is applied to the ink that should adhere to the recording medium due to the speed difference, and the ink quickly expands. It can be peeled off from the thermal transfer medium and an image with good image quality can be obtained.

<Example> Next, an example of a thermal transfer recording apparatus to which the above-described means is applied will be described with reference to the drawings.

FIG. 1 is a perspective explanatory view showing a recording section of a serial type thermal transfer recording device.

In the figure, reference numeral 1 denotes a cassette which houses an ink ribbon 2 serving as a thermal transfer medium, and is detachably loaded into a conveyor belt 3. Also said carry.

A recording head 4 is mounted on the recording head 3, in which a plurality of heating elements are arranged in a line and generate heat according to an image signal.

The recording head 4 is not particularly limited as long as it is a so-called thermal head, but a head that presses the ink ribbon 2 against the recording sheet 5, which is a recording medium, only in the vicinity of the heat generating part is preferably used. Therefore, the heating element array is provided near the end of the head substrate (the downstream end in the conveyance direction of the ink ribbon 2), and more specifically, the distance from the end of the head substrate to the end of the heating element is 300 μm or less. It is preferable to use a so-called edge head in which a glaze layer is provided only in the vicinity of the heating element.

The recording head 4 can be swung in the direction of arrow C by an up-down mechanism (not shown), and during recording, the head is lowered and the platen 6 is moved through the ink ribbon 2 and the recording sheet 5 fed by the feeding roller 11. 117I is pressed, and when not recording, the head is amplified to release the 117I press.

Further, the carriage 3 is connected to a heel 7c which is passed between pulleys 7a and 7b, and the carriage 3 is guided to the carriage rail 8 by driving a carriage motor 7d connected to the boot IJ 7a. It is configured to move back and forth.

Next, the conveyance of the ink ribbon 2, which is carried by the carriage 3 and selectively heated by the recording head 4, will be explained.

The ink ribbon 2 has a heat-transferable (heat-melting, heat-softening, heat-sublimation, etc.) ink layer formed on a base film, which is wound around a supply reel Ia in a cassette j, From the reel 1a to the guide roller Ib, the conveying means 9, the guide roller Ibz, the recording head 4, which will be described later.
Guide roller 1b.

It is wound around the take-up reel IC via Iba.

The conveying means 9 for the ink ribbon 2 is provided upstream of the recording head 4 in one general feeding direction of the ink ribbon 2, and between the guide rollers 1b1 and lbz.

Specifically, as shown in FIG. 1, the ink ribbon 2 is inserted between a conveyance roller 9a and a pressure roller 91) that presses the conveyance roller and rotates as a result of rotation. is transported in the six directions of arrows.

The drive mechanism for the transport roller 9a is provided in the carriage 3, and a gear 9d fixed to a transport shaft 9c that can engage with the transport roller 9a meshes with an intermediate gear 9e, and this intermediate gear 9e meshes with a pinion gear 9f. are doing. Further, the pinion gear 9f is configured to be able to mesh with a rank 9g provided in the main body of the apparatus parallel to the carriage rail 8.

Further, the pinion gear 9f is connected to the rack 9g by an interlocking mechanism (not shown) when the recording head 4 is moved down.
When the rack 9g is engaged with the rack 9g and the head is raised, the engagement with the rack 9g is released.

Therefore, when the carriage 3 moves in the direction of the arrow B during recording, the conveyance roller 9a rotates via the pinion gear 9'' meshed with the rank 9g, etc., and conveys the ink ribbon 2 in the six directions of the arrow.

The take-up reel 1c is configured to be engageable with a take-up shaft 10 connected via a take-up motor and a friction clutch (not shown). Therefore, as the carriage 3 moves, the ink ribbon 2 is conveyed by the conveyance means 9 in the six directions of the arrows, and is applied with a constant forward tension by the drive of the take-up motor and the action of the friction clutch, and is then placed on the take-up reel IC. be wound up.

Here, the ratios of the gears 9d to 9r are set so that the rotational circumferential speed of the conveying roller 9a that conveys the ink ribbon 2 is slightly slower than the moving speed of the carriage 3. Specifically, the rotational peripheral speed of the conveyance roller 9a is set to be 93% or more and less than 100% of the moving speed of the carriage 3, more preferably 95% or more and 98% or less. In this embodiment, the value is set to 97%.

As mentioned above, if the rotational circumferential speed of the conveying roller 9a is made slightly slower than the moving speed of the carry nozzle 3, the relative moving speed of the recording sheet 5 with respect to the movement of the recording head 4 during printing will be lower than the relative movement speed of the ink ribbon with respect to the movement of the recording head 4. The relative movement speed of 2 will be slightly slower.

Therefore, when the recording head 4 generates heat during recording, the melted or softened ink expands due to the heat, and furthermore, when the ink ribbon 2 is slightly stretched due to the heat and the tension applied to the ink ribbon 2, the recording head 4 Since there is a slight difference in the relative speed of the recording sheet 5 and the ink ribbon 2 with respect to the movement of the recording sheet 5, stress is applied to the melted or softened ink adhering to the recording sheet 5.

That is, due to the relative speed difference, the expansion of the ink and the elongation of the ink ribbon 2 are absorbed, and microscopically, the ink and the ink ribbon 2 are in a state where they do not slip relative to the recording sheet 5. This ink expansion and ink ribbon 2
According to experiments conducted by the present inventor, the relative speed difference that can absorb the elongation of is 93% or more and less than 100%, preferably 95%
The range is 98% or more.

Further, considering the heated ink, although this ink does not slip against the recording sheet 5, it is sandwiched between the header film of the ink ribbon 2 of the recording sheet 5 and the ink ribbon 2, and the relative speed is The image is transferred by stretching it due to the difference. Therefore, the ink is quickly peeled off from the hese film, and an ink image with good image quality is transferred to the recording sheet 5.

Although the conveying means 9 can be provided downstream of the recording head 4 in the conveyance direction of the ink ribbon 2, it is preferable to provide it upstream as in the embodiment described above.

When the conveying means is provided on the upstream side, if the forward tension on the take-up reel IC side is set to a constant value,
The state of separation between the ink ribbon 2 and the recording sheet 5 becomes constant. Furthermore, if the forward tension is set relatively strong, even if slack occurs in the ink ribbon 2 being conveyed due to disturbance etc. during recording, the slack is quickly forwarded by the tension, and the take-up reel I
It is wound up and absorbed by C. Further, since the forward tension does not exceed the tension generated by the take-up reel 1c, problems such as breakage of the ink ribbon 2 do not occur.

On the other hand, when the conveying means 9 is arranged downstream of the recording head 4 in the conveying direction of the ink ribbon 2, when the ink ribbon 2 becomes slack, the forward tension by the winding rule lc is applied as described above. Since it is difficult to absorb, it is necessary to increase the bank tension (tension between the supply reel 1a and the recording head 4) applied to the ink ribbon 2. At this time, the recording head 4 moves in the direction of arrow B with the head down, and the force due to the frictional force between the ink ribbons 2 acts on the ink ribbon 2 in the upstream direction. The forward tension is stronger than the puncture tension. Therefore, when the conveying means 9 is provided on the downstream side, it is necessary to use an ink ribbon 2 having strength to withstand the forward tension.

In this embodiment, since a so-called encyclopedia is used as the recording head 4, the ink ribbon 2 and the recording sheet 5 come into pressure contact only at the glazed portion of the recording head 5. Therefore, even if a relative speed difference occurs between the ink ribbon 2 and the recording sheet 5 with respect to the recording head 4, unnecessary strong force is rarely applied to the ink ribbon 2.
In this respect as well, it is possible to prevent the ink ribbon 2 from breaking, and
This can prevent the recording sheet 5 from being smudged by the ink ribbon 2.

Although the above-mentioned embodiment shows an example of a serial type thermal transfer recording device, the present invention does not need to be limited to the serial type. The present invention can also be applied to a line-type thermal transfer recording device that performs recording by conveying a recording sheet.

<Effects of the Invention> As described above, the present invention transfers and records a stable image on a recording medium with relatively low smoothness by providing a slight speed difference between the thermal transfer medium and the recording medium. I can do it.

Furthermore, the thermal transfer medium is effectively prevented from slipping on the recording medium. Furthermore, when transporting the thermal transfer medium, it is not affected much by the coefficient of friction of the thermal transfer medium, so there is greater freedom in selecting the material and manufacturing method of the thermal transfer medium.
This is something that can help reduce costs.

[Brief explanation of the drawing]

FIG. 1 is a perspective illustration of a serial type thermal transfer recording device according to an embodiment of the present invention. ■ is a cassette, 1a is a supply reel, lbl to Iba are guide rollers, 1c is a take-up reel, 2 is an ink ribbon, 3 is a carriage, 4 is a recording head, 5 is a recording sheet, 6 is a platen, 7a and 7b are pulleys , 7C is a heald, 7d is a carriage motor, 8 is a carriage rail, 9 is a transport means, 9a is a transport roller, 9b is a pressure roller, 9c is a transport shaft, 9d is a gear, 9e is an intermediate gear, 9f is a pinion gear, 9g is a rank, 10 is a winding shaft, and 11 is a feeding roller.

Claims (3)

[Claims] (1) In a thermal transfer recording device in which a recording head presses a thermal transfer medium and a recording medium and performs recording by moving the recording head and the thermal transfer medium and recording medium relatively, thermal transfer to the recording head is performed. A thermal transfer recording apparatus characterized in that a conveying means for conveying the thermal transfer medium is configured such that the amount of movement of the medium is slightly smaller than the amount of movement of the recording medium relative to the recording head. (2) The amount of movement of the thermal transfer medium with respect to the recording head,
The thermal transfer recording apparatus according to claim 1, wherein the amount of movement of the recording medium relative to the recording head is set to 93% or more and less than 100%. (3) Claim (1) or claim (2), wherein the conveyance means is provided upstream in the direction of movement of the thermal transfer medium than the recording head.
) The thermal transfer recording device described in ).