JPH07411B2 - Multicolor printer - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an ink sheet color boundary detection device in a thermal transfer type color printer.

[Background of the Invention]

As a conventional thermal transfer type color printer, there is known, for example, one in which an ink sheet and a recording sheet are sandwiched between a fixed line head and a platen and the ink sheet and the recording sheet are moved together and transferred. This is because the ink sheet, the paper and the line head have almost the same width, and three primary color inks are prepared with a constant length in the direction orthogonal to the longitudinal direction of the line head. Color printing is performed by printing.

FIG. 1 is an explanatory diagram of the ink sheet 5. In this sheet, each ink layer obtained by applying and drying a heat-meltable or heat-sublimable ink composed of three primary colors by subtractive color mixture, for example, yellow (Y), magenta (M), and cyan (C) on a film base ( The width W and the length l are equal) and they are continuously formed in a predetermined order. Here, the length l of each ink layer is naturally set to be slightly longer than the length of the paper with some allowance.

The recording head 3 is a direct heating type thermal head in which a heating element is used as a recording element, and an electrically heating type thermal head 3 (the film base of the ink sheet is made conductive so that the heat generated from the juule is used. In the above, a head provided with a needle electrode and a return electrode is used respectively.

By the way, in such a thermal transfer color printer,
When the first color is transferred and then the second and third colors are transferred to the same sheet in an overlapping manner, the length l of each ink layer is longer than the length of the sheet as described above. It is necessary to detect the first part of the and prepare for transcription.

Conventionally, the detection of this color boundary portion is performed by, for example, Japanese Patent Laid-Open No. 209595/1983.
As can be seen in Japanese Patent Laid-Open Publication No. 2004-242, the ink sheet is irradiated with light and the reflected light or transmitted light thereof is predicted to have different pass bands set according to the spectral distribution of each color.
There is one in which two photosensors are used to detect through one filter, and the detection is performed by the combination of the presence or absence of each photosensor output.

However, such a method requires two filters and two optical sensors, and has a drawback that the structure is complicated and expensive.

[Purpose of the present invention]

SUMMARY OF THE INVENTION The present invention has been made in view of the above drawbacks of the prior art, and an object of the present invention is to provide a multicolor printing printer having a simple structure and capable of detecting the color boundary portion of an inexpensive semitransparent ink sheet.

[Outline of the present invention]

The apparatus according to the present invention focuses on the fact that the order of each color of the ink sheet is predetermined, and a monochromatic light source 8 that is arranged close to the front surface side of the ink sheet 5 and irradiates the ink sheet with light. A reflection means 9 arranged at a position close to the back surface side of the ink sheet and not overlapping the recording sheet and reflecting light passing through the ink sheet toward the ink sheet, and a reflection means 9 close to the front surface side of the ink sheet. And a light receiving means 10 which receives the light reflected by the reflecting means and outputs a signal, and a judging means for judging the boundary of a plurality of colors with the ink sheet based on the signal level of the light receiving means. It has 12 to 19.

〔Example〕

FIG. 2 is a structural explanatory view showing an example of an apparatus according to the present invention. In this figure, 1 is a recording paper (plain paper), 3 is a thermal head, 4 is a platen, and 5 is an ink sheet. The thermal head 3 is lightly pressed against the recording paper 1 via the ink sheet 5, the recording paper 1 and the ink sheet are sent together in the direction of arrow a, and the ink sheet 5 is transferred at the time of transfer by the second and third colors. Is sent in the direction of arrow b by a driving means (not shown) to prepare for transfer of the second and third colors.

Reference numeral 8 is a single monochromatic light source for partially irradiating the ink sheet 5, for example, a red LED is used. Reference numeral 9 denotes a reflector installed so as to face the light source 8 through the ink sheet 5,
Is a light receiving means for receiving the reflected light from the reflection plate 9 through the ink sheet 5, and is installed adjacent to the light source 8 here, and for example, a phototransistor is used.

As shown in FIG. 1, the ink sheet 5 has ink layers of three primary colors formed in plane order, or, as shown in FIG. 3, a colorless portion 50 having no ink layer is formed at the boundary of each color. What has been done is used. A mark 51 (see FIG. 2) for detecting the end may be formed near the end of the ink sheet 5.

The operation of the thus constructed device will be described below.

FIG. 4 is a diagram showing the relationship between the wavelength and the relative emission intensity when a red LED is used as the light source 8. The red LED irradiates the ink sheet 5 with red light having a wavelength range of 600 nm to 700 nm.

FIG. 5 is a characteristic diagram showing the spectral sensitivity of cyan (C) color in the ink sheet 5, showing a high transmittance for light having a wavelength of about 600 nm or less.

FIG. 6 is a characteristic diagram showing the spectral sensitivity of the yellow (Y) color in the ink sheet 5, showing a high transmittance for light having a wavelength of about 550 nm or more.

Returning to FIG. 2, when the light from the light source 8 having the spectral sensitivity as shown in FIG. 4 causes the ink layer of the ink sheet 5 to be C color having the characteristics as shown in FIG. The amount of light passing through is extremely small, as is clear from the relationship between the two characteristics. On the other hand, when the ink layer of the ink sheet 5 is the Y color having the characteristics as shown in FIG. 6, the light from the light source 8 is transmitted at a high rate, is reflected by the reflection plate 9, and is again ink sheet. The light is then received by the light receiving means 10. When the ink sheet is broken, the light from the light source 8 is directly reflected by the reflecting plate 9 and received by the light receiving means 10, and the light is hardly attenuated. Similarly, in the ink sheet shown in FIG. 3, when light passes through the colorless portion 50, there is almost no light other than the attenuation of the light in the colorless portion.

In the ink sheet shown in FIG. 1, in the case of the end mark (black mark) 51, the light transmission amount is very small.

FIG. 7 shows a light receiving means according to each part of the ink sheet 5.
FIG. 6 is a diagram showing what magnitude of signal can be obtained from 10.

As is clear from this diagram, the light receiving means 10 can obtain signals of different levels ec and e _Y depending on whether the ink layer of the ink sheet 5 is of C color or Y color. Further, when the ink sheet is torn, signals of different levels are obtained, E _B , E _O at the colorless portion, and E _C at the end mark, respectively.

The signal from the light receiving means 10 is applied to a judging means (not shown) for judging the level of the output signal, and at the same time, the signal level is judged and its change, for example, change from ec to e _Y is detected. Thus, the color boundary portion between the two is detected.

In this embodiment, the M color has not been described, but since the M color is transmitted to the red in the same manner as the Y color, the boundary between the Y color and the M color cannot be detected, but the Y color and the M color are not detected. Since the length l of both C and C is manufactured to be the same as shown in FIG. 1, it can be easily assumed, and it is ignored because it is not cumulatively added even if there is a dimensional error. It is possible.

The level of the signal from the light receiving means 10 is shown in FIG.
E _B, E _O, it is possible to detect Yotsute to determining Taka whether summer to Ee, breaking the ink sheet 5, the passage of the colorless portion 50, the end mark 51, respectively.

FIG. 8 is a sectional view showing a specific structural example of the device according to the present invention. Here, the ink sheet 5 is set in the cassette case 57.
The thermal head 31 is retracted in the direction of the arrow A when the cassette case 57 is attached. Reference numerals 55 and 56 denote roll-shaped sheets in the cassette case 57.

The reflector 9 is installed in advance on the cassette case 57 side, and the light source 8 and the light receiving means 10 are provided on a thermal head stand 32 that moves together with the thermal head 31.

In the apparatus thus configured, the light source 8 and the light receiving means 10 are both provided on the same thermal head base 32 side, so that the electric circuit is not separated. By retracting the thermal head 32, the cassette case containing the ink sheet can be easily attached.

FIG. 9 is a configuration block diagram showing an example of a determination circuit for determining the signal level from the light receiving means 10. This determination circuit is a buffer amplifier 1 that amplifies the signal from the light receiving means 10.
1. A comparator 1 for comparing the signals from the buffer amplifier 11 with predetermined reference voltages E _B , e _Y , ec (where E _B > e _Y > ec)
2,13,14, inverters 15,16,17 for inverting the signals from the respective comparators 12,13,14, an AND circuit 18 for inputting the signal from the comparator 12 and the signal from the inverter 16, the comparator 13 AND circuit for inputting the signal from the inverter and the signal from the inverter 17
9. A display 21 for detecting and displaying the breakage of the ink sheet 5 by the signal from the inverter 15, and a display 21 for detecting and displaying that the ink layer is Y-color or M-color by the signal from the AND circuit 18. 22, a display 23 for detecting and displaying that the ink layer is C color by a signal from the AND circuit 19, and a display 24 for detecting and displaying the end of the ink sheet 5 by a signal from the comparator 14. It is configured. Here, since the order of each color of the ink sheet 5 is determined in advance, such a circuit can be used in accordance with the signal level from the light receiving means 10.
Ink sheet breakage detection, ink layer color boundary detection, and ink sheet end detection can be performed.

In each of the above embodiments, the red LED is used as the light source, but the green LED may be used as the light source. In this case, the boundary between the Y and M colors of the ink layer or M
It is possible to detect the boundary between the color and the C color.

In addition, a blue LED may be used as the light source, and in this case, it is possible to detect the boundary between the C and Y colors or the Y and M colors.

Further, in the embodiment, an example in which a fixed recording head having a width substantially the same as the width W of the recording paper is used is shown, but the present invention is not limited to this. For example, the length of the recording paper, that is, the length l of each color ink layer of the ink sheet. It is also possible to move the moving recording head having substantially the same size as that in the width direction.

Furthermore, in the embodiment, an ink sheet having three color ink layers of cyan, magenta, and yellow has been described. However, the present invention is not limited to this, and various ink sheets having four color ink layers in which black color is added to the ink sheet are available. Ink sheet can be used.

Further, in the above description, the case where the invention is applied to the thermal transfer type color printer has been illustrated, but the invention can also be applied to the impact type color printer.

[Effect of the present invention]

As described above, according to the present invention, the reflecting means that reflects light from the front surface side to the back surface side of the semitransparent ink sheet and is arranged at a position not overlapping the recording paper is again the front surface side of the ink sheet. Since it reflects light that is not visible, it is possible to determine a boundary between a plurality of colors even though the translucent ink sheet has a low reflectance, especially on the surface of the ink sheet.

In addition, since the light of the monochromatic light source passes through the ink sheet twice and is incident on the light receiving means, a certain color and a different color can be obtained as compared with the case where the monochromatic light source and the light receiving means are arranged simply by sandwiching the semitransparent ink sheet. Since the difference between the output from the light receiving means and the light emitting means is doubled, the accuracy of the determination of the boundaries of the plurality of colors by the determination means is improved.

[Brief description of drawings]

1 and 3 are explanatory views of an ink sheet, FIG. 2 is a structural explanatory view showing an example of an apparatus according to the present invention, and FIG. 4 is red.
A characteristic diagram showing the relationship between the wavelength of the LED and the received light intensity, FIGS. 5 and 6 are diagrams showing the spectral sensitivity characteristics of the C and Y colors of the ink sheet, and FIG. 7 is the signal level from the light receiving means. FIG. 8 is a cross-sectional view of a concrete configuration example of the device of the present invention, and FIG. 9 is a configuration block diagram showing an example of a determination circuit. 1 ... Recording paper, 3 ... Recording head 4 ... Platen, 5 ... Ink sheet, 8 ... Light source, 9 ... Reflector, 10 ... Light receiving means.

Claims (1)

[Claims] 1. A multicolor printer for transferring a plurality of colors onto a recording sheet by superposing a semitransparent ink sheet and a recording sheet on which a plurality of colors are sequentially provided and transferring the plurality of colors onto the recording sheet. A monochromatic light source that is arranged close to the ink sheet and irradiates light toward the ink sheet, and a light that is arranged close to the back side of the ink sheet and that does not overlap the recording sheet and that passes through the ink sheet. A reflecting means for reflecting the light toward the ink sheet, a light receiving means arranged in proximity to the front surface side of the ink sheet, for receiving the light reflected by the reflecting means, and outputting a signal; A multicolor printer comprising: a determination unit that determines boundaries of a plurality of colors of the ink sheet based on the signal level.