JPH01290465A - thermal transfer printer - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention uses a transfer sheet coated with ink and a thermal head configured by arranging a plurality of heating resistors in a line to print a sheet of recording paper. The present invention relates to a thermal transfer printer that performs transfer recording.

Conventional technology FIG. 4 shows an outline of the main parts of a conventional thermal transfer printer.

In the figure, 1 is a platen, 2 is a thermal head, 3 is a transfer sheet coated with ink, and 4 is a sheet of recording paper. (not shown).

When performing transfer recording, the thermal head 2 presses the recording paper 4 against the platen 1 via the transfer sheet 3, and while rotating the platen 1 in the direction of the arrow, the thermal head 2 heats the ink on the transfer sheet 3. Then, transfer recording is performed (for example, Japanese Patent Laid-Open No. 148779/1983).

Problems to be Solved by the Invention However, when performing transfer recording by winding the recording paper 4 around the platen 1 in this way, some of the recording paper may remain curled or even bent due to being wound around the platen. There were times when I would do something like that.

Furthermore, since the outer circumference of the platen must be increased by the length of the recording paper, the diameter of the platen becomes large and the apparatus becomes large.

Another method is to transfer the recording paper using a rotatably provided pinch roller and a rotatably provided capstan without winding it around the platen, and press the recording paper and transfer sheet against the platen with a thermal head to perform transfer recording. However, it is necessary to transport a sheet of recording paper between the platen and the thermal head to a state where it can be transferred and recorded, and the leading edge of the recording paper may get caught, causing jamming.

In addition, when transporting the recording paper between the platen and the thermal head to a state where it can be transferred and recorded, if the amount of transport is small, the transfer recording will be performed on the platen near the end of recording, contaminating the platen, and eventually the recording paper There is also a risk that this could lead to contamination of the recording paper, so it was necessary to detect the predetermined amount of recording paper to be transported in advance.

In view of the above problems, the present invention provides a compact and highly accurate thermal transfer printer.

Means for Solving the Problems In order to solve the above problems, the present invention includes a thermal head configured by arranging a plurality of heating resistors in a line on a head substrate, and presses the thermal head through a recording paper and a transfer sheet. a rotatable pinch roller, a capstan that presses the recording paper against the pinch roller and transports the recording paper, and a capstan that is positioned opposite to the capstan with respect to the platen so as to detect the leading edge of the recording paper. A paper detection sensor is provided at a predetermined position such that The opening gradually narrows toward the paper detection sensor, and the opening area is at least within the detection area of the paper detection sensor at the position of the paper detection sensor.

According to the above-described structure, the present invention transfers a sheet of recording paper while being held between a rotatably provided pinch roller and a rotatably provided capstan, and transfers the recording paper via a transfer sheet. Since transfer recording is performed by pressing the paper against the platen with a thermal head, there is no need to wind the recording paper around the platen.

Therefore, there is no curling or even bending caused by the recording paper being wound around the platen, and there is no need for the outer circumference of the platen to be equal to the length of the recording paper. The diameter of the device also becomes smaller, and the device becomes smaller.

In addition, when the recording paper is not transferred to the recording paper by the thermal head and the recording paper is held between the pinch roller and the capstan and transported in the direction of the thermal head, the paper guide section opens the opening where the recording paper enters. Since the opening is made wider and the opening gradually narrows toward the paper detection sensor, the leading edge of the recording paper can easily enter the opening area of the paper guide section. Since the recording paper is configured such that it is within the detection area of the paper detection sensor, the leading edge of the recording paper can be reliably detected.

Embodiment FIG. 1 is a schematic sectional view showing an embodiment of a thermal transfer printer of the present invention. In FIG. 1, 1° is a thermal head constructed by arranging a plurality of heating resistors (not shown) in a row on a head substrate, 11 is a sheet of recording paper, and 12 is the heat generated by the thermal head 1o. A transfer sheet coated with ink that is melted or sublimated by the heat of the resistor is wound and stretched around a rotatably provided supply reel 13 and take-up reel 14 and stored in a sheet cassette 16. 16 is a rotatably provided platen; 17 is a rotatably provided pinch roller; 18 is a capstan that holds and transfers the recording paper 11 by pressure with the pinch roller 17; 19.20
A cassette guide 20 guides the sheet cassette 15 to a predetermined position, and a cassette guide 20 that guides the supply reel 13 also serves as a paper guide section 21 for the recording paper 11.

Reference numeral 22 indicates an upper paper guide, and 23 indicates a lower paper guide, which are constructed so that the opening on the entrance side of the recording paper 11 is wide and gradually narrows.

The operation will be explained below using FIGS. 1, 2, and 3. applied to the transfer sheet 12 on the recording paper 11,
When performing transfer recording with ink that melts or sublimates with heat, if the recording paper 11 does not have a predetermined length, the platen 16
Ink that melts or sublimates with heat is transferred directly to the
This stains the surface of the platen 16 and causes contamination of the recording paper 11. For this purpose, 24 is a paper detection sensor provided at a predetermined position to detect the leading edge of the recording paper 11 and confirm that the length of the recording paper 11 is a predetermined length.
For example, a reflective photosensor is used, in which a light emitting element such as an infrared light emitting diode and a light receiving element of a phototransistor that receives this reflected light are placed side by side, and a change in reflected light is detected when an object passes in front of this pixel element. I can do it. Usually, the equivalent circuit of this sensor is shown in Figure 3 (, ), where ■ is the voltage, IF is the current of the light emitting diode,
IC is the current of the phototransistor, d is the distance between the sensor and the object, and the relationship between the distance d of the object to be detected and the current of the phototransistor, that is, the collector output current, is as shown in Figure 3), and the optimal detection area is has.

Further, the paper detection sensor 24 is provided so that the upper surface of the lower paper guide 23 and the lower surface of the upper paper guide 22 form a width area in which the recording paper 11 is detected. Further, the upper paper guide 22 is provided with an opening 240 through which the emitted light from the paper detection sensor 24 and the reflected light from the passing object pass, and the lower paper guide 23 is in a state where there is no object (recording paper 11). Similarly, an opening 230 is provided so that the light from the light emitting element is not reflected from the upper surface of the lower paper guide 23. 25 and 26 are sheet guides that are integrally attached to the thermal head 1o, and 2 is a sheet guide that also serves as a cover for the pinch roller 17. A paper guide 28 is also provided between the capstan 18 and the platen 16.

The operation of the thermal transfer link of this embodiment configured as described above will be explained below. First, the recording paper 11 is pressed and held between the pinch roller 17 and the capstan 18, and as the capstan 18 rotates in the direction of arrow B, the recording paper 11
is sent in the direction of arrow C. At this time, the transfer sheet 12
is stretched between the sheet guides 25 and 26 of the thermal head 1o, and is stretched so as to guide the recording paper 11 in the direction of the lower paper guide 23 with the paper guide 28. The stretched transfer sheet 12 is guided by the paper guide 28, and is further guided by the paper guide section 21 of the cassette guide 2o and the upper paper guide 2.
2. The recording paper 11 is detected by the paper detection sensor 24 with the lower paper guide 23.
The leading edge of the recording paper 11 is detected by the paper detection sensor 24. With this, the length of the predetermined recording paper 11 can be confirmed, and therefore, as shown in FIG. Ru. Next, a plurality of heating resistors provided on the head substrate of the thermal head 10 generate heat according to the information, and the ink applied to the transfer sheet 12 and melted or sublimated by heat is transferred and recorded on the recording paper 11. . At this time, the capstan 18 rotates in the direction indicated by the arrow, and presses the recording paper 11 between the pinch roller 17 and transports the recording paper 11 to perform transfer recording. Further, the transfer sheet 12 is wound up by the take-up reel 14 at any time after the transfer recording is completed.

Transfer recording is performed on the recording paper 11 in this way, and the capstan 18 and the pinch roller 17 move the recording paper 1 in the direction of the arrow.
1 is transferred and discharged, and the recording ends.

As described above, according to this embodiment, the recording paper 11 is held and transferred by the capstan 18 and the pinch roller 17, and the transfer sheet 12 and the recording paper 11 are transferred to the platen 16.
is pressed into contact with the thermal head 10, a plurality of heating resistors provided on the head substrate generate heat according to the information, and the ink applied to the transfer sheet 12, which melts or sublimates with heat, is transferred and recorded onto the recording paper 11. Therefore, there is no need to wind the recording paper 11 around the platen 16, and therefore, there is no curling or even bending caused by the recording paper 11 being wound around the platen 16. The outer circumferential length of the platen 1e is not required to be equal to the length of the recording paper 11, so the diameter of the platen 16 is also reduced, and the apparatus becomes compact.

Also, the cassette guide 200 paper guide section 21. A paper guide section composed of an upper paper guide 22 and a lower paper guide 23 is configured such that the opening where the recording paper 11 enters is widened and gradually narrows toward the paper detection sensor 24. Therefore, the recording paper 11 is guided smoothly to the paper detection sensor 24, and there is less jamming of the recording paper 11, and the upper surface of the lower paper guide 23 and the lower surface of the upper paper guide are the detection areas of the paper detection sensor 24 that detects the recording paper 11. Since it is provided so that the leading edge of the recording paper 11 passes through can be reliably detected and it can be confirmed that the recording paper 11 has a predetermined length, it is extremely useful in practice.

Effects of the Invention As described above, according to the present invention, transfer recording is performed by pressing the recording paper against a platen via a transfer sheet with a thermal head while holding and transporting the recording paper between a capstan and a pinch roller. Therefore, there is no need to wind the recording paper around the platen, which prevents the recording paper from curling or bending.
Transfer can be performed even with a platen having a small diameter, and the device can be downsized.

In addition, the opening of the paper guide section through which the recording paper enters is widened,
Since the opening gradually narrows toward the paper detection sensor, the recording paper can enter easily, and furthermore, the opening area of the paper guide section is within the detection area of the low detection sensor at the position of the bottom detection sensor. Therefore, the leading edge of the recording paper can be detected reliably, and a highly accurate thermal transfer printer can be realized.

[Brief explanation of the drawing]

1 and 2 are schematic sectional views of a thermal transfer printer according to an embodiment of the present invention, FIG. 3(a) is an equivalent circuit diagram of a detection sensor, and FIG. A characteristic diagram showing the relationship between distance d and collector output current, and FIG. 4 is a schematic diagram of the main parts of a conventional thermal transfer printer. 10... Thermal head, 11... Recording paper, 12... Transfer sheet, 16...
Platen, 17...Pinch roller, 18...
... Capstan, 22 ... Upper paper guide, 2
3...Lower paper guide, 24...Paper detection sensor. Name of agent: Patent attorney Toshio Nakao and 1 other person r+
W-Grudge 3 for Shuaikan

Claims (1)

[Claims] A thermal head configured by arranging a plurality of heat generating resistors in a line on a head substrate, a sheet of recording paper, a transfer sheet coated with ink, and the thermal head via the recording paper and the transfer sheet. a rotatable pinch roller that presses the recording paper; a rotatable capstan that presses the recording paper with the pinch roller and transports the recording paper; and a rotatable capstan that transports the recording paper; A paper detection sensor disposed at a position opposite to the capstan with respect to the platen, and a paper guide section that guides the recording paper to the paper detection sensor, and the paper guide section widen the opening where it enters,
The thermal transfer printer is configured such that the opening gradually narrows toward the paper detection sensor so that at the position of the paper detection sensor, the opening area is at least within the detection area of the paper detection sensor.