JPH07102731B2 - Label position detection device for label printer - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a label position detecting device for detecting the position of a label that is removably attached to a strip-shaped mount in a label printer so that the label can be printed at a predetermined position.

2. Description of the Related Art A conventional label printer, as shown in FIG. 5, for example, conveys a label paper 10 on which a label 11 is releasably attached at a predetermined interval on a strip-shaped mount 12 in a predetermined direction while predetermining each label 11 in a predetermined manner. Data such as weight and price is printed at the position, and the printed label 11 is peeled from the mount 12 and attached to a product or the like.

In such a label printer, in order to print at a predetermined position on the label 11, it is necessary to accurately detect the position of the label.

Therefore, as is conventionally seen in, for example, Japanese Utility Model Publication No. 59-25670, an issuing element in which the label paper 10 is moved in the direction of the arrow as shown in FIG.
The label of the backing sheet 12 is made by the detection circuit as shown in FIG. 6 which uses the transmission type photo sensor 1 including the light receiving element 1b and the light receiving element 1b.
The amount of light passing through the portion to which 11 is attached and the portion only to the backing sheet 12 are converted into a voltage, and these voltages are compared with the reference voltage Vr by the comparator 2 to discriminate both the above-mentioned portions. A label position detecting device for detecting the position was provided.

Alternatively, by using a detection circuit using a reflection type photo sensor, the amount of light reflected by the above two parts is converted into a voltage, and each voltage is compared with a reference voltage to discriminate both parts to determine the position of the label 11. There was also something to detect.

In addition, a specific detection portion (notch, black mark, etc.) that represents the label position is provided on the backing sheet 12, and both portions are discriminated by the difference in the amount of transmitted light or the amount of reflected light between the detection portion and other portions. It is also possible to detect 11 positions.

However, in such a conventional label position detection device, due to the difference in the material and thickness of the label used, the characteristics of the photo sensor and the variation of the optical axis and distance at the time of attachment, the difference in the ink material and the density in the case of the black mark, etc. In some cases, the generated voltage varies due to the change in the amount of passing light or the amount of reflected light, which causes a deviation from the reference voltage, and it may not be possible to reliably detect the label position.

Therefore, it is troublesome to adjust the variable resistor 8 so that the width of the voltage Vd of both high and low levels according to the difference in the amount of light detected from the point d of the detection circuit of FIG. 6 is accurately distributed to both sides of the reference voltage Vr. It was necessary to do the work.

Also, as mentioned above, there are various types of label paper, such as one with a label attached to the backing paper, one with a notch (notch) formed as a detection portion indicating the label position, and one with a black mark printed. Therefore, when these different types of label paper are used, it is necessary to perform the troublesome work of resetting the reference voltage Vr by adjusting the variable resistor 9 in the detection circuit of FIG. 6 each time.

Otherwise, only the designated label paper can be used, which is difficult for the user to use.

Aim The present invention has an object to solve the problems in such a conventional label position detecting device and to eliminate the above adjustment work.

In order to achieve the above-mentioned object, the present invention transfers a label that is releasably attached to a strip-shaped backing paper in a certain direction and attaches the label of the backing paper in order to print at a predetermined position on the label. By converting the amount of transmitted light or the amount of reflected light of the exposed portion and only the backing sheet or the detected portion and other portion into a voltage, and comparing these voltages with a reference voltage to discriminate both portions, the label In the label position detecting device in the label printer for detecting the position, the higher one is detected based on the signal obtained by converting the amount of light passing through or the amount of reflected light of both parts of the backing sheet into voltage during the position detection of the label. The reference voltage automatic setting means for automatically setting the reference voltage to the optimum voltage level intermediate between the voltage level of 1) and the voltage level of the lower one is provided.

By configuring as described above, due to the difference in the type of label paper and the various variations as described above, the amount of passing light or the amount of reflected light of the label paper changes, and the detected voltage obtained by converting them into a voltage is Even if it fluctuates, the reference voltage automatic setting means automatically sets the reference voltage to the optimum level based on that voltage, so there is no need to re-adjust as in the past, and the label position can always be detected reliably. You can

Hereinafter, specific description will be given based on embodiments of the present invention.

FIG. 1 is a circuit diagram showing an embodiment of the present invention, and the same parts as those in FIG. 6 are designated by the same reference numerals.

In this embodiment, the detection unit 4 is configured by connecting in parallel a series circuit of the protection resistor R ₁ and the light emitting element 1a and a series circuit of the light receiving element 1b and the detection resistor 3 between the DC power source Vcc and the ground. There is.

As the light emitting element 1a that constitutes the transmissive photo sensor 1, it is preferable to use an infrared LED that matches the spectral sensitivity (wavelength) of the photo transistor that is the light receiving element 1b.

When the label paper 10 is moved between the light emitting element 1a and the light receiving element 1b as shown in FIG. 5, the current flowing through the light receiving element 1b changes in accordance with the amount of light passing therethrough, which causes the detection resistor 3
Detection voltage Vd obtained at point d after being converted into a voltage by
Is input to the negative input terminal of the comparator 2 via the input resistor R ₂ .

Also, input this detection voltage Vd to the A / D converter 5,
It is converted into a digital signal and taken into a microcomputer (hereinafter abbreviated as “CPU”) 6.

The detection voltage Vd has a high level in a portion having a large amount of passing light on various label sheets, and has a low level in a portion having a small amount of passing light.

Therefore, the CPU 6 discriminates between the higher voltage level V _H and the lower voltage level V _L of the detection voltage V d, and performs the arithmetic processing of adding the digital values of both levels to halve (V _H + V _L ) / 2
Is set as the reference voltage Vr.
Send to converter 7.

The D / A converter 7 converts it into an analog voltage to generate a reference voltage Vr, which is input to the positive input terminal of the comparator 2 via the input resistor R ₃ .

Therefore, since the reference voltage Vr is set to the optimum level and the variation width of the detection voltage Vd is always accurately distributed to both sides with respect to the reference voltage Vr, the comparator 2 changes the detection voltage Vd, that is, the label. Accurately distinguish different parts of the paper and invert the output. Thereby, the label position on the mount can be surely detected.

In this embodiment, the CPU 6 and the D / A converter 7 function as a reference voltage automatic setting means.

FIGS. 2 (a), (b) and (c) show examples of different types of label paper 10, respectively. (A) shows the label 12 only attached to the mount 12, and (b) shows both sides of the mount 12. The notch 13 is formed as a detection portion indicating the label position on the part,
Similarly, in FIG. 6C, a black mark 14 is printed as a detection portion.

When each of these label sheets is detected by the label position detecting device shown in FIG. 1, the detection voltage Vd output from the detecting section 4 is detected.
Are respectively shown by the solid line a, the broken line b, and the alternate long and short dash line c in FIG.

The solid line a shows the voltage change due to the difference in the light amount between the portion of the label paper 10 of FIG. 2 (a) having only the backing paper 12 and the portion of the label paper 12 attached to the backing paper 12, and the broken line b shows the change in voltage of FIG. 2 (b). ) Label paper 10
The change in voltage due to the difference in the amount of light between the part of the mount 12 only and the part of the notch 13 is indicated by the one-dot chain line c in FIG.
The change in voltage due to the difference in light quantity between the part where the label 11 is attached and the part of the black mark 14 on the mount 12 of 10 are respectively shown.

Then, according to this embodiment, Vra, Vrb, and Vrc are set as the reference voltage of the optimum voltage level intermediate between the higher voltage level and the lower voltage level of the detection voltage Vd in any case.

Further, even if the type of label paper used is the same, the detection voltage Vd changes due to various variations as described above, but since the reference voltage set by the CPU 6 is fed back according to the change, the label voltage of the label paper is changed. Not only the variation but also the variation of the photo sensor itself and the secular change can be included in the stable determination.

FIG. 4 is a circuit diagram showing another embodiment of the present invention,
The same parts as those in FIG. 1 are designated by the same reference numerals, and the description thereof will be omitted.

In this embodiment, the reference voltage selection circuit 21 composed of the switching elements S ₁ , S ₂ , and S ₃ and a plurality of voltage levels different from each other suitable for the type of label paper expected to be used in advance (in this example, A reference voltage generating circuit 22 for generating three types of reference voltages Vr ₁ , Vr ₂ , Vr ₃ is provided.

Then, the CPU 6 discriminates both high and low levels of the digital conversion data of the detection voltage Vd fetched from the A / D converter 5,
Reference voltage selection circuit that selects the most suitable reference voltage
Feed to 21, turn on one of the switching-element S ₁ to S _3, select the optimum voltage of the reference voltage generating circuit 22 three types by connexion generated in the reference voltage Vr ₁ through Vr ₃ reference Voltage
Input to comparator 2 as Vr.

Therefore, in this embodiment, the CPU 6 and the reference voltage selection circuit 21
Also, the reference voltage generation circuit 22 functions as a reference voltage automatic setting means.

Also according to this embodiment, one photo sensor can automatically cope with various kinds of label paper. Further, if the types of reference voltages that can be selected are increased, it is possible to cope with variations in the label paper and the photo sensor itself, changes over time, and the like to some extent.

〔The invention's effect〕

As described above, the label position detecting device in the label printer according to the present invention, regardless of what type of label paper is used, always detects only the part to which the label of the mount is attached and the mount while detecting the position of the label. The reference voltage is automatically set to an optimum voltage level intermediate between the higher voltage level and the lower voltage level based on the signal obtained by converting the transmitted light amount or the reflected light amount of the part or the detection part and the other part into a voltage. Therefore, the label position can be detected reliably without adjustment.

Even if the paper quality or thickness of the mount or label or the density of the black mark in the detection area varies during long-time detection, or if the sensor sensitivity changes, it is fed back and the reference voltage is changed. Since the voltage level is always corrected to the optimum voltage level, the label position can always be reliably detected even if the detection operation is continued for a long time.

Moreover, the circuit configuration of the reference voltage automatic setting means and the process for realizing it by the function of the microcomputer are simple.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing an embodiment of the present invention, FIGS. 2 (a), (b) and (c) are illustrations of different types of label paper, and FIG. 3 is an embodiment of FIG. Fig. 2 (a) (b)
FIG. 4C is an explanatory view showing the relationship between the detected voltage and the optimum reference voltage when each type of label paper is detected, FIG. 4 is a circuit diagram showing another embodiment of the present invention, and FIG. 5 is label paper. And FIG. 6 is a circuit diagram showing an example of a label position detecting device in a conventional label printer. 1 ... Transmission type photo sensor, 1a ... Light emitting element 1b ... Light receiving element, 2 ... Comparator 3 ... Detecting resistor, 4 ... Detecting section 5 ... A / D converter 6 ... Microcomputer (CPU) 7 ... … D / A converter, 10 …… Label paper 11 …… Label, 12 …… Backing paper 13 …… Notch (detection part) 14 …… Black mark (detection part) 21 …… Reference voltage selection circuit 22 …… Reference voltage generation circuit

Claims (1)

[Claims] 1. A label-attached part and a mount-only part of the mount for transferring a label releasably attached to a strip-shaped mount in a predetermined direction and printing at a predetermined position of the label. Alternatively, a label adapted to detect the position of the label by converting the amount of passing light or the amount of reflected light of the detection part and the other part into a voltage, and comparing these voltages with a reference voltage to discriminate the both parts. In the label position detecting device in the printer, during detection of the position of the label, the higher voltage level and the lower voltage level are constantly detected based on the signals obtained by converting the passing light amount or the reflected light amount of both parts of the mount into voltage. A label position detecting device in a label printer, characterized in that a reference voltage automatic setting means for automatically setting the reference voltage to an optimum voltage level in the middle of the levels is provided. Place