JPH07246746A - Ink ribbon detector - Google Patents

Abstract

PURPOSE:To provide an ink ribbon detector accurately detecting the position of an ink ribbon. CONSTITUTION:A driver 5 drives a light emitting element 6. The light emitting element 6 emits two kinds of lights having different wavelengths alternately at an appropriate time interval. These emitted lights transmit through an ink ribbon 7 and are attenuated according to transmission characteristics peculiar to respective ink colors to be incident on a light detection element 8. The light detection element 8 converts the incident lights to currents and the currents are converted to analogue voltage values by a voltage converter 9 and two comparators 10-1, 10-2 compare the analogue voltage values with preset comparison voltage values 11-1, 11-2 and output the comparison results as binary data. By this constitution, a pair of binary data different at every ink colors can be obtained and the color of the ink ribbon can easily be discriminated on the basis of a pair of the binary data and the position of the ink ribbon can be easily detected.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink ribbon detection device for detecting the color of an ink ribbon.

[0002]

2. Description of the Related Art Conventionally, printing on a thermal transfer recording apparatus has been
An ink ribbon in which ink is applied on a base film is used. This ink ribbon is in the form of a long strip having almost the same width as the recording paper.

In the case of an ink ribbon used for multicolor printing (color printing), a subtractive color mixture of Y (yellow: yellow), M (magenta: red dye), and C (cyan: greenish blue) is usually used. Ink of the three primary colors, or four colors of ink in which Bk (black: black) specially used for printing characters and the like is added to these three colors, which are repeatedly applied in sequence in the longitudinal direction on the base film. Ribbon is used. Then, these colors are mixed in various proportions by overcoating to express various shades and gradations.

In this multicolor printing, a detection device as shown in FIG. 10 or 11 is used to detect the color or position of the ink ribbon. In FIG. 10, a specific marking portion 2 is formed between the colors formed on the ink ribbon 1.
Is provided and the color of the ink is determined by reading various marks printed on the marking portion by the reflective photosensor 3 when the ink ribbon 1 moves.

Further, in FIG. 11, a specific marking portion 2'is provided between each color set formed on the ink ribbon 1 '(in the case of the figure, one set of three colors a, b and c). ,
When the ink ribbon 1'moves, the mark is read by the reflective photosensor to determine the initial position of the specific color, for example, the color a.

Further, without using the marking as described above,
For example, as shown in Japanese Examined Patent Publication No. 2-59070, a method of directly determining a color by an optical sensor is known.

[0007]

By the way, the method of making a specific marking between the colors shown in FIG. 10 has no meaning because the color cannot be discriminated by one kind of marking, and thus three kinds of markings are always required. Become. Therefore, on the one hand, it is complicated to manage the marking and the corresponding color at the time of producing the ink ribbon, and on the other hand, the control of the sensor for discriminating the type of marking at the time of printing is troublesome. Further, the method of marking between the color sets shown in FIG. 11 is uneconomical because the color of the portion that has been idle-fed is wasted until a specific head color is detected. If you try to rewind to this, this will increase the work time on the one hand,
On the other hand, control for rewinding is required, which also causes various problems.

In order to detect the color or position of the ink ribbon by using the marking as described above, in addition to the ink portion used for printing (printing) on the ink ribbon,
Since an area used as a marking portion is also required, the ink ribbon becomes longer and the ink ribbon cassette becomes larger. In addition, in addition to the above, in the production of the ink ribbon, a step of adding a mark is added to the step of applying the ink, which causes a problem that the price of the ink ribbon increases.

Further, the method of directly discriminating colors with an optical sensor is generally as shown in the spectral sensitivity characteristic curve of FIG.
The spectral sensitivity characteristic of the optical sensor is not so good for light having a wavelength of 700 nm (nano millimeters) or less in the visible light region, and further, the characteristic of the optical sensor and the variation of the ink ribbon thickness In consideration of the above, in this method, the detected values of colors, particularly C (cyan) and Y (yellow), sometimes fluctuate back and forth with respect to the reference value, and
There is a possibility that the difference in color cannot be clearly discriminated. Therefore, it is hard to say that it is a method that can always correctly distinguish colors.

In view of the above conventional circumstances, the object of the present invention is to
An object of the present invention is to provide an ink ribbon detection device that directly and correctly detects the color of the ink ribbon.

[0011]

The structure of the ink ribbon detection device according to the present invention will be described below. The ink ribbon detection device of the present invention has a first wavelength that emits light of a first wavelength.
Light emitting element, a second light emitting element that emits a second wavelength light different from the first wavelength light, and a light emission control unit that alternately operates the first and second light emitting elements; On the basis of the output from the light receiving element, which receives the light emitted from the second light emitting element through the ink ribbons having a plurality of colors, the comparing means which compares the output from the light receiving element with a reference value, and the output from the comparing means. And a judging means for judging the color of the ink ribbon.

The emitted light is configured to pass through the ink ribbon and enter the light receiving element, for example, as described in claim 2. Further, for example, as described in claim 3,
It is configured to reflect on the ink ribbon and enter the light receiving element.

The light emitted from the first and second light emitting elements is configured to be green and red, for example. Further, for example, as described in claim 5, it is configured to be yellow and red. Furthermore, for example, as described in claim 6, it is configured to be blue and red. Further, for example, as described in claim 7, it is configured to have a plurality of reference values for comparing the outputs of the light receiving elements.

[0014]

In the ink ribbon detecting device of the present invention, the first light emitting element emits light of green, yellow, or blue wavelength on the one hand, and the second light emitting element emits light of the red wavelength on the other hand under the control of the light emission control means. The light of is emitted alternately. The light receiving element receives the light emitted from the first and second light emitting elements and transmitted through the ink ribbon having a plurality of colors, for example, yellow, magenta, and cyan, or the light reflected by the ink ribbon. The comparison means compares the output from the light receiving element with a reference value. The judging means judges the color of the ink ribbon based on the output from the comparing means.

As a result, the color of the ink ribbon can be detected correctly.

[0016]

Embodiments of the present invention will be described in detail below with reference to the drawings. FIG. 1 is a block diagram showing the configuration of one embodiment. In the figure, the driver 5 drives the light emitting element 6 to emit light under the control of a control unit (not shown). The light emitting element 6 is driven and controlled by the driver 5 and alternately emits two types of light having different wavelengths at appropriate time intervals, for example, at a time interval at which the feeding speed of the ink ribbon 7 can be ignored. The light emitted by this light emission passes through the ink ribbon 7, is attenuated according to the transmission characteristics peculiar to each color of the ink applied to the ink ribbon 7, and is incident on the light receiving element 8. The light receiving element 8 converts the incident transmitted light into a current and outputs the converted current to the voltage converter 9. Voltage converter 9
Converts the current input from the light receiving element 8 into an analog voltage value and outputs this voltage value to the two comparators 10-1 and 10-2. The comparator 10-1 compares the voltage value input from the voltage converter 9 with a preset comparison voltage value 11-1 and outputs the comparison result as binary data to the control unit. Similarly, the comparator 10-2 compares the voltage value input from the voltage converter 9 with the preset comparison voltage value 11-2 and outputs the comparison result to the control unit as binary data.

FIG. 2 shows the arrangement of the light emitting element 6, the ink ribbon 7 and the light receiving element 8. As shown in the figure, the ink ribbon 7 is sent out from the sending core 7-1 from the upper right direction to the lower left direction shown by the arrow A in the drawing, and is wound by the winding core 7-2 which is rotationally driven by a drive mechanism (not shown). To be A light emitting element 6 is disposed above the ink ribbon 7 and a light receiving element is disposed below the ink ribbon 7. Of course, the light emitting element 6 may be disposed below and the light receiving element may be disposed above.

On the ink ribbon 7, an ink color a (for example, yellow Y), an ink color b (for example, magenta M), and an ink color c (for example, cyan C) are sequentially and repeatedly applied. The light transmittance for each of these colors differs depending on the wavelength.

In FIG. 3, yellow (Y) and magenta (M)
Spectral transmission characteristics of each color are shown by taking an ink ribbon formed of three colors of cyan and cyan (C) as an example. In the figure, the vertical axis shows the transmittance and the horizontal axis shows the wavelength of light in the visible region.
As shown in the figure, yellow (Y) has wavelengths of 400-4.
The transmittance is about 20% at 40 nm, and thereafter 520 nm
The transmittance increases sharply as the wavelength becomes longer,
The transmittance of approximately 70% is maintained from 0 nm to 700 nm. Magenta (M) has a wavelength of 400 to 440 nm
The transmittance is about 40%, about 5% at 520 to 570 nm, about 65% at 630 to 700 nm, and abruptly lowering and rising in the middle. Then, the transmission characteristic of cyan (C) shows a sine curve in which the lower part is 40% and the apex is 70% at 400 to 550 nm, and thereafter, the transmittance sharply decreases to 600 nm, and 6
Almost 7% is maintained from 00 nm to 700 nm.

Since the transmittance is different for each wavelength of light and each color of ink in this way, the same ink color is transmitted by alternately using two lights of different wavelengths, and if this is converted into a voltage, Different voltage values depending on the wavelength of light can be obtained for one color. On the other hand, for light of the same wavelength,
It is possible to obtain different voltage values for each color of ink.

Subsequently, in FIG. 4, Y, M and C are also the same as above.
The spectral reflectance characteristics of each color are shown by taking the case of an ink ribbon composed of three colors as an example. Also in the figure, the vertical axis is the transmittance,
The horizontal axis represents the wavelength of light in the visible region. As shown in the figure, in this case as well, yellow (Y) has wavelengths of 400-4.
At 60 nm, the reflectance is about 3 to 5%, and thereafter the reflectance sharply increases as the wavelength becomes longer, and the reflectance increases from 520 nm to 7%.
The reflectance of about 80% is maintained up to 00 nm. Magenta (M) has a reflectance of about 25 to 29% at a wavelength of 400 to 440 nm and about 2 to about 500 to 570 nm.
3%, about 79% at 650 to 700 nm, and a sharp fall and rise in the middle thereof. And
The reflection characteristic of cyan (C) shows a sine curve in which the lower part is 20% and the apex is 63% at 400 to 550 nm.
Almost 3% is maintained from m to 700 nm. As described above, the spectral reflectance characteristics for each color are slightly different from the spectral transmittance characteristics shown in FIG. 3 except that the reflectance ratio is slightly different from the transmittance ratio. That is, also in this case, the reflectance for each wavelength of light and the color for each ink differ with the same tendency as the transmittance. Therefore, also in this case, if two lights having different wavelengths are alternately used to reflect the same ink color and the voltage is converted, it is possible to obtain different voltage values corresponding to the wavelength of light for one color. it can. On the other hand, for light of the same wavelength, different voltage values can be obtained for each color of ink.

In this embodiment, when lights of two different wavelengths are used and are alternately transmitted through the ink ribbon, the respective colors a, b, c of the ink ribbon 7 are respectively applied to the respective lights.
The comparison voltages 11-1 and 11-2 are set so that the above-mentioned feature remarkably appears in the binary data output from the voltage converter 9. Further, similarly, it is possible to discriminate the ink colors of the ink ribbons up to a maximum of four colors by using lights having appropriate two wavelengths different from each other.

FIGS. 5 (a) and 5 (b) show in the form of tables a specific example of performing color discrimination when the ink colors are three colors. In the diagram shown in FIG. 3A, two different wavelengths of light of 563 nm (green) and 650 nm (red) emitted from the two-color light emitting element 6 are shown in the upper column, and the ink ribbon is shown in the vertical column of the left column. 7 shows three types of ink colors, yellow (R), magenta (M), and cyan (C). In the columns corresponding to these two types of wavelength light and the three types of ink colors, when these colors of light are transmitted through these ink colors, the light receiving element 8 of FIG. The voltage value output via the device 9 is shown. That is, the wavelength 563
In the case of light (green) of nm, the voltage value due to the transmitted light is yellow (R), magenta (M), cyan (C) for the ink color.
On the other hand, 330 mV, 60 mV and 90 mV are shown respectively. These voltage values are represented by the vertical broken line 31 indicating the green wavelength region in the ribbon spectral transmission characteristic diagram of FIG. 3 and the respective curves Y.
The transmittances indicated by the points where (1), M (2), and C (3) intersect are the voltage values corresponding to the light amounts of around 70%, around 5%, and around 30%, respectively.

In the case of light (red) having a wavelength of 650 nm, the voltage value due to the transmitted light is 1 for ink colors yellow (R), magenta (M), and cyan (C), respectively.
It is shown to be 910 mV, 1850 mV and 350 mV. These voltage values are also points at which the vertical broken line 32 indicating the red wavelength region and the respective curves Y (1), M (2), and C (3) intersect in the ribbon spectral transmission characteristic diagram of FIG. Show the transmittance, around 70%, around 60%, 1
It is a voltage value corresponding to a light amount of about 0%.

At this time, if appropriate comparison voltages (reference values) are set for the comparison voltages 11-1 and 11-2 in accordance with the output from the voltage converter 9 as described above, the two comparators 10 are provided.
From the outputs -1, 10-2, four pairs of binarized data of two wavelengths of light corresponding to one ink color are obtained.

For this, for example, with respect to the voltage value in the chart of FIG. 5 (a), 260 mV is set as the comparison voltage 11-1 as the comparison voltage at the wavelength 563 nm, and the wavelength 650 n
1100 mV as the comparison voltage at m
Set to -2. These comparison voltages 260 mV, 110
0 mV is approximately 48% of the green transmittance of FIG.
(See point 33 in FIG. 3) and the converted voltage value when the transmittance of red is approximately 35% (see point 34 in FIG. 3), which corresponds to the spectral transmission in FIG. In the characteristic diagram, points at which any one of the three colors is separated are shown.

As a result, for the wavelength 560 nm (green), the conversion voltage 330 mV of yellow (Y) is higher than the comparison voltage 260 mV, so that the comparator 10-1 outputs "1". Also, for the wavelength of 650 nm (red), the conversion voltage of yellow (Y) is 1910 mV.
Is higher than the comparison voltage of 1100 mV, the comparator 10
"-1" is output from -2. Similarly, in the case of magenta (M), "0" and "1" are output, and in the case of cyan (C), "0" and "0" are output. As a result, the binary data shown in the chart of FIG. From this chart, the outputs of the comparators 10-1 and 10-2 are "1,
If it is "1", the ink color is yellow (Y), if the output is "0, 1", it is magenta (M), and if the output is "0, 0", it is cyan (C). Easy to find.

As is clear from FIG. 3, the wavelength 56
Similar results are obtained by using a wavelength of 580 nm (yellow) instead of 3 nm (green). Further, as is clear from FIG. 4, even when the reflected light is used instead of the transmitted light, the same result can be obtained. When the reflected light shown in FIG. 4 is used, the comparison voltage value at the point corresponding to the reflectance of about 50% may be set regardless of whether the wavelength of the light is red, green, or yellow. , The corresponding converted voltage values differ depending on the wavelength, and thus two comparison voltage values are set in this case as well.

The voltage value determined for each ink color corresponding to the different wavelength light shown in FIG. 5 (a) is the value shown in the above chart depending on the characteristics of the light receiving element 8 or the circuit configuration of the voltage converter 9. May take different values, but even in that case, if the values are different from this chart, the tendency of strength and weakness corresponding to wavelength and color is shown in FIG. 3 or 4. Since it follows the tendency indicated by the ribbon spectral characteristic curve, similar results can be obtained by setting an appropriate reference value suitable for that case.

Next, color determination in the case of four colors will be described. As shown in the chart of Fig. 6 (a),
The high wavelength hg and the low wavelength lw are shown beside the upper column. These wavelengths are, for example, as shown in FIG.
m and 650 nm for red. The four ink colors are shown in the left column vertically as ink color 1, ink color 2, ink color 3 and ink color 4. These colors are, for example, yellow (Y), cyan (C), magenta (M), and black (Bk) as shown in the ribbon transmission characteristic diagram of FIG. 7. In the figure, a ribbon transmission characteristic curve of black (Bk) is added to the ribbon transmission characteristic diagram of FIG. 3 for display. However, since black (Bk) does not transmit light at all, its ribbon transmission characteristic curve is the same as the horizontal axis in the characteristic diagram.

In the table of FIG. 6 (a), these two wavelengths hg and 1w correspond to four kinds of ink color 1, ink color 2, ink color 3 and ink color 4 in the corresponding columns. Corresponding to the amount of transmitted light when these lights are transmitted, the light receiving element 8 and the voltage converter 9 of FIG.
The voltage value output via is shown. That is, when the wavelength is hg, the voltage value due to the transmitted light is ink color 1,
V for ink color 2, ink color 3 and ink color 4, respectively
a, Vb, Vc and Vd. These voltage values are, for example, in the ribbon spectral transmission characteristic diagram of FIG. 7, characteristic curves yellow (Y), magenta (M), cyan (C), and black (Bk) that intersect the vertical solid lines 41 indicating the blue wavelength region, respectively. )
Is a voltage value corresponding to the transmittance indicated by the intersection point of. In the figure, for reference, ink color 1, ink color 2, ink color 3
In order to facilitate contrasting the ink color 4 with, for example, yellow (Y), magenta (M), cyan (C) and black (Bk), the color symbols Y, M, and
Color numbers 1, 2, 3, and 4 of the chart are shown in parentheses in C and Bk, respectively.

As is clear from the ribbon transmission characteristic diagram of FIG. 6, if the voltage value corresponding to the point of the transmittance of about 35% in the 500 nm (blue) region (see point 43 in the figure) is the comparison voltage Vs, this 500 nm (blue) against Vs for comparison voltage
The transmitted light conversion voltages Va and Vb of Y (1) and C (2) are binarized to "1". In addition, V
M (3) and Bk with 500 nm (blue) for s
The transmitted light conversion voltages Vc and Vd of (4) are binarized to "0". The vertical middle column of the chart of FIG. 6B shows the output of the comparator 10-1 of FIG. 1 in such a case.

Similarly, as is clear from the ribbon transmission characteristic diagram of FIG. 8, the transmittance in the 650 nm (red) region, that is, the voltage value corresponding to the point of about 35% (see point 44 in the figure) is used as the comparison voltage Vt. Then, the transmitted light conversion voltages Ve and Vg of Y (1) and M (3) by 650 nm (red) with respect to this comparison voltage are binarized to "1". Also,
This comparison voltage is C by 650 nm (red) with respect to Vt.
The transmitted light conversion voltages Vf and Vh of (2) and Bk (4) are binarized to "0". The vertical right column of the chart in Fig. 6 (b)
The output of the comparator 10-2 in FIG. 1 in such a case is shown.

As described above, by transmitting the light of the appropriate two wavelengths to any of the four ink colors, a pair of binary data different for each color is obtained as shown in the chart of FIG. 6 (b). be able to.

From this, it is apparent that good results can be obtained by using the reflected light as in the case of the three colors. In FIG. 8, the four colors yellow (Y), cyan (C),
A magenta (M) and black (Bk) ribbon reflection characteristic diagram is shown, and this figure is also shown by adding a black (Bk) ribbon reflection characteristic curve to the ribbon reflection characteristic diagram of FIG. 4.
Also in this figure, the black (Bk) ribbon reflection characteristic curve is the same as the horizontal axis in the characteristic diagram. As is clear from the ribbon reflection characteristic diagram, the voltage value corresponding to the point 46 having the reflectance of about 25% is set to the comparison voltage V in the region of 500 nm (blue).
If the voltage value corresponding to the point 47 having a transmittance of about 40% is set as the comparison voltage Vt in the 650 nm (red) region, the four colors of yellow (Y), cyan (C), and magenta (M) are set. ), And FIG. 6 for black (Bk).
The same four pairs of binary data as the chart shown in (b) are obtained.

As is apparent from FIG. 2B, the comparator 10-
If the output of 1, 10-2 is "1, 1", the ink color is 1,
If the output is "1, 0", the ink color is 2, and the output is "0,
It is easily found that the ink color is 3 if it is "1" and the ink color is 4 if the output is "0, 0".

In this embodiment, the comparison voltage Vs set for the conversion voltages Va to Vd corresponding to the wavelength hg and the ink colors 1, 2, 3, and 4, the wavelength lw and the ink color 1,
The comparison voltage Vt set for the conversion voltages Ve to Vh corresponding to 2, 3, and 4 is obtained from the following inequality according to the present invention.

Min (Va, Vb)>Vs> max (Vc, Vd) min (Ve, Vg)>Vt> max (Vf, Vh) The above “min” has two values Va, Vb (or Ve, V).
g), whichever takes the smaller value.
“Ax” indicates that the larger one of the two values Vc and Vd (or Vf and Vh) is taken.

In the case of three colors, if the inequality is Va>Vs> max (Vb, Vc) min (Ve, Vf)>Vt> Vg, two wavelengths hg, lw to be selected at this time,
Corresponding to the comparison values Vs and Vt set for this,
The binary data of one pair to three pairs obtained from the outputs of the comparators 10-1 and 10-2 are represented by "(1, 1),
(0, 1), (0, 0) ".

The inequality may be min (Va, Vb)>Vs> Vc min (Ve, Vg)>Vt> Vf. In this case, the comparators 10-1 and 10-2 are used.
The binary data obtained from the output of "(1, 1),
(1, 0), (0, 1) ". In addition, the comparator 10-
Binary data obtained from the output of 1, 10-2,
Inequalities can also be set to be “(1,0), (0,1), (0,0)”.

By the way, in the above embodiment, two comparators are used to compare two different comparison voltages and converted voltages. However, if only one comparator is used, the cost of the entire apparatus can be reduced. it can.

Even in this case, an apparatus and method capable of correctly performing color discrimination of maximum and four colors, as in the case described above, will be described below as another embodiment. Figure 9
[Fig. 6] is a block diagram showing a configuration of another embodiment. As shown in the figure, the configuration of this embodiment is the same as that of the previous embodiment shown in FIG.
Each comparator 10 (similar to the comparator 10-1 in FIG. 1) is used. Other configurations are the same as those in FIG.

In the figure, the comparator 10 outputs binary data by using one comparison voltage value 11. Then, in this case, the conversion voltage value V such that the two comparison voltage values Vs and Vt described in the chart of FIG. 5 or 6 become Vs = Vt.
If a, Vb, Vc and Vd, and Ve, Vg, Vf and Vh are obtained, the comparator 10 uses the comparison voltage value (Vs or Vt) as shown in FIG. A pair of binary data unique to each similar ink color is converted into conversion voltage values Va and Ve, Vb and Ve, Vc and Vf, and V.
It can be output corresponding to d and Vg, respectively.

As described above, in order to satisfy Vs = Vt, it is necessary to adjust the light emission energy of the light emitting element for each different wavelength in consideration of the light transmittance peculiar to each ink color and the light receiving sensitivity of the light receiving element. . By doing so, the converted voltage value can be appropriately changed corresponding to the emission energy even for the same wavelength and the same transmittance, so that it is desirable to adjust each converted voltage value to an appropriate value. The comparison voltage value can be set.

Generally, the value of the conversion voltage value V is determined by V = E (emission energy) × C (transmittance for each ink color) × S (current conversion efficiency for each wavelength) × R (voltage conversion resistance). Therefore, the condition for Vs = Vt is that the voltage conversion resistor R
Is a constant value, El: light energy of wavelength lw Eh: light energy of wavelength hg Sl: current conversion efficiency of light receiving element at wavelength lw Sh: current conversion efficiency of light receiving element at wavelength hg Cl1: wavelength lw Cl2: Transmittance of ink color 2 at wavelength lw Cl3: Transmittance of ink color 3 at wavelength lw Cl4: Transmittance of ink color 4 at wavelength lw Ch1: Transmittance of ink color 1 at wavelength hg Ch2: Transmittance of ink color 2 at wavelength hg Ch3: Transmittance of ink color 3 at wavelength hg Ch4: Transmittance of ink color 4 at wavelength hg Then, min (Eh × Ch1 × Sh, Eh × Ch2 × Sh)>
max (El x Cl2 x Sl, El x Cl4 x Sl) and min (El x Cl1 x Sl, El x Cl3 x Sl)>
max (Eh × Ch3 × Sh, Eh × Ch4 × Sh) must be satisfied. To summarize the above inequality, Eh × Sh × min (Ch1, Ch2)> El × Sl ×
max (Cl2, Cl4) and El x Sl x min (Cl1, Cl3)> Eh x Sh x
max (Ch3, Ch4), and from this, El × {Sl × min (Cl1, Cl3) / Sh × ma
x (Ch3, Ch4)}>Eh> El × {Sl × max
(Cl2, Cl4) / Sh × min (Ch1, Ch
2)} can be derived.

Then, by controlling El and Eh so as to satisfy the above inequality, it is possible to set a comparison voltage value common to two wavelengths such that Vs = Vt.
As a result, the comparator 10 shown in FIG. 9 can correctly perform color discrimination up to a maximum of four colors, and thus can correctly detect the position of the ink ribbon.

In each of the above-mentioned two embodiments, the maximum four colors are used for the color discrimination. However, the number of wavelengths emitted by the light emitting element is not limited to four, and the number of wavelengths can be increased accordingly. By increasing the number of comparators and obtaining the comparator output corresponding to each color composed of three or more binary data, the position detection can be performed in the same manner even in the case of five or more ink colors. It is possible.

[0048]

As described in detail above, according to the present invention, it is possible to obtain different binary data sets for each color by photoelectrically converting the transmission or reflection of the ink ribbon due to the different wavelength light. Therefore, it becomes easier to directly detect the color of the ink ribbon directly for each color, and therefore it is not necessary to additionally provide a detection mark or the like other than ink on the ink ribbon. Since the manufacturing process of the ink ribbon is also simplified, the cost is reduced, and in practical printing work, waste of time such as sending back the ink ribbon is eliminated and printing efficiency is improved.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of an example.

FIG. 2 is a diagram showing an arrangement state of a light emitting element, an ink ribbon, and a light receiving element in one embodiment.

FIG. 3 is a diagram showing yellow (Y), magenta (M), and cyan (C) spectral transmission characteristics of an ink ribbon.

FIG. 4 is a diagram showing yellow (Y), magenta (M), and cyan (C) spectral reflection characteristics of an ink ribbon.

5 (a) and 5 (b) are charts for explaining a specific example in the case of performing ink color discrimination of three colors.

6 (a) and 6 (b) are charts for explaining a method of discriminating ink colors of four colors.

FIG. 7 is a diagram showing spectral transmission characteristics of yellow (Y), magenta (M), cyan (C), and black (Bk) of an ink ribbon.

FIG. 8 is a diagram showing yellow (Y), magenta (M), cyan (C), and black (Bk) spectral reflection characteristics of an ink ribbon.

FIG. 9 is a block diagram showing the configuration of another embodiment.

FIG. 10 is a diagram (No. 1) for explaining a conventional method for determining the ink ribbon color.

FIG. 11 is a diagram (No. 2) for explaining a conventional method for determining the ink ribbon color.

FIG. 12 is a diagram showing a spectral sensitivity characteristic of an ordinary optical sensor.

[Explanation of symbols]

1, 1'ink ribbon 2, 2'marking part 3 reflection type photo sensor 5 driver 6 light emitting element 7 ink ribbon 7-1 sending core 7-2 winding core 8 light receiving element 9 voltage converter 10, 10-1, 10 -2 Comparator 11-1, 11-2 Comparison voltage Y (1), M (2), C (3), Bk (4) Light transmission or reflection characteristic curve

Claims (7)

[Claims] 1. A first light emitting element that emits light of a first wavelength, a second light emitting element that emits light of a second wavelength different from the light of the first wavelength, and the first and second light emitting elements. A light emitting control means for alternately operating the light emitting elements, a light receiving element for injecting light emitted from the first and second light emitting elements through ink ribbons having a plurality of colors, and an output from the light receiving element. An ink ribbon detection device comprising: a comparison means for comparing with a reference value; and a judgment means for judging the color of the ink ribbon based on the output from the comparison means. 2. The ink ribbon detection device according to claim 1, wherein the emitted light passes through the ink ribbon and enters the light receiving element. 3. The ink ribbon detection device according to claim 1, wherein the emitted light is reflected by the ink ribbon and is incident on the light receiving element. 4. The ink ribbon detection device according to claim 1, wherein the first light emitting element emits green light and the second light emitting element emits red light. 5. The ink ribbon detection device according to claim 1, wherein the first light emitting element emits yellow light and the second light emitting element emits red light. 6. The ink ribbon detection device according to claim 1, wherein the first light emitting element emits blue light and the second light emitting element emits red light. 7. The ink ribbon detection device according to claim 1, wherein a plurality of the reference values are provided.