Patent Application
20180009249
This application is based upon and claims the benefit of priority from Japanese Patent Application No. P2016-135006, filed Jul. 7, 2016, the entire contents of which are incorporated herein by reference.
Embodiments described herein relate generally to a label printer and a method for improving detection precision by the label printer.
Conventionally, a label printer carries out detection of a printing position selectively using a transmission type sensor or a reflection type sensor depending on a printing medium to print on a label paper (label sheet) or a tag paper (tag sheet). Further, conventionally, there is a technology for improving detection properties of a paper end with both the transmission type sensor and the reflection type sensor.
Incidentally, the transmission type sensor and the reflection type sensor are often arranged to be close to the top of a substrate. Thus, there is a problem that light from a light emitting element of one sensor migrates to a light receiving element side of the other sensor and it is consequently difficult to improve detection precision of the printing position.
Light emission of the light emitting element of the sensor that is not used for the position detection may be stopped depending on the type of a paper in order to reduce influence of migrating light. However, it is desired to enable both the sensors to operate for detection of the paper end in order to improve the detection properties of the paper end as stated above. In this way, conventionally, a technology capable of realizing both the improvement of the detection precision of the printing position and the improvement of the detection precision of the paper end is desired.
In accordance with an embodiment, a label printer comprises a transmission type sensor configured to enable a first light emitting element to emit light to irradiate a printing medium with the light and to detect light transmitted through the printing medium; a reflection type sensor configured to enable a second light emitting element to emit light to irradiate a printing medium with the light and to detect light reflected by the printing medium; and a light emission control module configured to alternately switch a single light emission period in which either the first light emitting element or the second light emitting element emits light and a both light emission period in which both the first light emitting element and the second light emitting element emit light.
A keyboard 8 is connected with the keyboard controller 5. A display device 9 is connected with the display controller 6. A thermal printer 10 is connected with the head driver 7. The head driver 7 and the thermal printer 10 print characters or barcodes with an ink ribbon on a label paper and a tag paper serving as printing mediums. The label paper is a sheet obtained by sticking labels on a rolled paperboard having high light transmission at fixed intervals. The tag paper is a sheet obtained by printing a dark color mark (black mark) for alignment on the back surface of a sheet.
Further, a sensor control circuit 11, a motor driver 12 and a communication I/F (Interface) 13 are connected with the CPU 1. A feed motor 23 and a ribbon motor 24 are connected with the motor driver 12. The feed motor 23 is a motor for conveying the printing medium such as the label paper and the tag paper. For example, a stepping motor can be used as the feed motor 23. The ribbon motor 24 is a motor for conveying an ink ribbon for printing. The CPU 1 is connected with a host computer 30 serving as a host machine via the communication I/F 13 and a wireless communication line.
In one embodiment, light emitting element 21a and light emitting element 22a emit light having the same wavelength or range of wavelengths. In another embodiment, light emitting element 21a and light emitting element 22a emit light having a different wavelength or a different range of wavelengths.
The sensor control circuit 11 is equipped with an I/O (Input/Output) port 40, a D/A (Digital/Analog) converter 41, operational amplifiers 42 and 46, and NPN type transistors 43 and 47. The sensor control circuit 11 is further equipped with resistors 44, 45, 48 and 49. Further, the sensor control circuit 11 is equipped with an A/D (Analog/Digital) converter 50.
The CPU 1 (refer to
The D/A converter 41 carries out D/A conversion on the input light emission instruction signal. An output signal from the ch1 of the D/A converter 41 is input between a base and an emitter of the NPN type transistor 43 after being amplified by the operational amplifier 42. An output signal from the ch2 of the D/A converter 41 is input between a base and an emitter of the NPN type transistor 47 after being amplified by the operational amplifier 46.
The NPN type transistor 43 applies a direct voltage Vcc to the light emitting element 21a of the transmission type sensor 21 if an output voltage of the operational amplifier 42 is applied between the base and the emitter. The light emitting element 21a emits light according to the direct voltage Vcc.
In the transmission type sensor 21, the light emitting element 21a and the light receiving element 21b are arranged in such a position relationship that the light emitting element 21a and the light receiving element 21b face each other across the printing medium. The light emitting element 21a emits the light to the printing medium. The light receiving element 21b detects the light transmitted through the printing medium.
The light receiving element 21b applies the direct voltage Vcc to the resistor 45 via a collector-emitter. The light receiving element 21b outputs a voltage generated in the resistor 45 to the channel ch1 of the A/D converter 50 as an output of the transmission type sensor 21.
The NPN type transistor 47 applies the direct voltage Vcc to the light emitting element 22a of the reflection type sensor 22 if an output voltage from the operational amplifier 46 is applied between a base and an emitter. The light emitting element 22a emits light according to the direct voltage Vcc.
In the reflection type sensor 22, the light emitting element 22a and the light receiving element 22b are arranged in such a manner that the light emitting element 22a and the light receiving element 22b are arranged in parallel in the same direction with respect to the printing medium. The light emitting element 22a emits the light to the printing medium. The light receiving element 22b detects the light reflected by the printing medium.
The light receiving element 22b applies the direct voltage Vcc to the resistor 49 via a collector-emitter. The light receiving element 22b outputs a voltage generated in the resistor 49 to the channel ch2 of the A/D converter 50 as an output of the reflection type sensor 22.
The A/D converter 50 carries out A/D conversion on the output voltage of the light receiving element 21b input to the channel ch1. The A/D converter 50 outputs a digital signal generated through the A/D conversion to the CPU 1 via the I/O port 40 as the output signal of the transmission type sensor 21.
Further, the A/D converter 50 carries out A/D conversion on the output voltage of the light receiving element 22b input to the channel ch2. The A/D converter 50 outputs a digital signal generated through the A/D conversion to the CPU 1 via the I/O port 40 as the output signal of the reflection type sensor 22.
Next, functional components of programs of the present embodiment are described.
The conveyance control section 51 carries out drive control of the feed motor 23 and the ribbon motor 24 via the motor driver 12 if receiving print data (print command) via the host computer 30 or the keyboard 8. In this way, the conveyance control section 51 controls paper conveyance by the feed motor 23 and controls cartridge conveyance by the ribbon motor 24.
In a case in which the feed motor 23 is the stepping motor, the conveyance control section 51 generates a pulse signal having frequency corresponding to a resolution designated by the print command, and outputs the pulse signal to the motor driver 12. The motor driver 12 controls a rotation angle (rotation amount) and a rotation speed of the stepping motor according to the input pulse signal.
Further, the conveyance control section 51 stops the feed motor 23 and the ribbon motor 24 if the end part detection section 54 detects an end part of the printing medium (label paper or tag paper).
The light emission control section 52 controls a light emission operation of the light emitting element 21a of the transmission type sensor 21 or the light emitting element 22a of the reflection type sensor 22 according to the type of the printing medium instructed in the print data (print command) input from the host computer 30 or the keyboard 8.
Further, the light emission control section 52 alternately switches a single light emission period and a both light emission period to control the light emission of the light emitting element 21a and the light emitting element 22a. The single light emission period refers to a period in which either the light emitting element 21a of the transmission type sensor 21 or the light emitting element 22a of the reflection type sensor 22 emits the light. The both light emission period refers to a period in which both the light emitting element 21a of the transmission type sensor 21 and the light emitting element 22a of the reflection type sensor 22 emit the light. Further, the light emission control section 52 arranges the both light emission period each time the conveyance control section 51 conveys the printing medium (for example, the label paper or the tag paper) by a predetermined distance.
The position detection section 53 detects a position indicating a print area on a paper if the conveyance of the paper is started. Further, the position detection section 53 detects the print area (that is, an area in which a label is stuck) on the label paper if the print command is a print command to the label paper. Further, the position detection section 53 detects a black mark serving as an index of the print area on the tag paper if the print command is a print command to the tag paper.
The end part detection section 54 detects the end part of the printing medium on the basis of the output of the light receiving element 21b of the transmission type sensor 21 or the light receiving element 22b of the reflection type sensor 22.
Next, a light emission control method of the light emitting elements 21a and 22a by the light emission control section 52 is described by exemplifying a concrete example of a light emission signal.
As shown in
The single light emission period is arranged in order to detect a position of a label, and the both light emission period is arranged in order to detect a paper end part. It is efficient that the detection of the paper end part is carried out at a timing at which the label paper is sent out by one step by the feed motor 23 (for example, the stepping motor) after the printing operation for one line is completed. Thus, the both light emission period is arranged at the end of the light emission period for one line, and is set as a shorter period than the single light emission period. Then, a longer period than the first half of the light emission period for one line is set as the single light emission period, and the light emitting element 22a which is not used for alignment is turned off. In this way, influence of sneaking of the light from the light emitting element 22a to the light receiving element 21b is reduced, and the precision of the alignment can be improved.
As shown in
The single light emission period is arranged in order to detect the black mark (dark color index mark) on the tag paper, and the both light emission period is arranged in order to detect the paper end part. Similar with the light emission control at the time of printing on the label paper as described above, a longer period than the first half of the light emission period for one line is set as the single light emission period, and the light emitting element 21a which is not used for the alignment is turned off. In this way, the influence of the sneaking of the light from the light emitting element 21a to the light receiving element 22b is reduced, and the precision of the alignment can be improved.
In
In this manner, in the label printer 100 of the present embodiment, the light emitting element of the sensor that carries out the position detection is continuously lighted, and on the other hand, the light emitting element of the sensor that does not carry out the position detection intermittently emits the light in a blinking manner. Further, a cycle of the blinking is synchronized with a cycle of the conveyance operation of the stepping motor as an example.
Further, the frequency at which the both light emission period is arranged is not limited to the forgoing example; the both light emission period may be arranged in a fixed cycle that is predetermined according to the paper conveyance operation. In other words, the both light emission period may be arranged each time the conveyance control section 51 conveys the printing medium for a predetermined number of lines. The both light emission periods may be arranged more closely than the example in
Next, operations for detecting the paper end part are described with reference to
Since the light from the light emitting element 21a is transmitted through a part of the label paper of a gap between a label and a label more easily, alight receiving level (in other words, the output voltage) of the light receiving element 21b of the transmission type sensor 21 is increased at the gap between the label and the label as shown in
The position detection section 53 detects a part where the light receiving level is equal to or greater than a predetermined threshold value as a position of the gap between the labels (so-called label gap). Further, the position detection section 53 infers a printing position from the position of the label gap to carry out an adjustment of the printing position.
On the other hand, a light receiving level of the light receiving element 22b of the reflection type sensor 22 periodically has a peak in a shape synchronized with the light emission pattern of the light emitting element 22a of the reflection type sensor 22 in general as shown in
In this manner, if the state in which the light receiving level of the light receiving element 21b of the transmission type sensor 21 is the HI and the light receiving level of the light receiving element 22b of the reflection type sensor 22 is the LO is continuous in a fixed period, the end part detection section 54 determines that the end part of the label paper is detected, in other words, paper shortage of the label paper is detected. In
If the paper end of the label paper is detected, the conveyance control section 51 stops the feed motor 23 and the ribbon motor 24. Further, the light emission control section 52 stops the light emission of the light emitting elements 21a and 22a as shown in
The reflectance of the light from the light emitting element 22a is reduced due to a black mark on the back surface of the tag paper. Thus, the light receiving level (in other words, the output voltage) of the light receiving element 22b of the reflection type sensor 22 is decreased at the position of the black mark as shown in
The position detection section 53 detects a part where the light receiving level is equal to or smaller than a predetermined threshold value as the position of the black mark. Further, the position detection section 53 infers a printing position from the position of the black mark to carry out an adjustment of the printing position.
As shown in
In this case, the end part detection section 54 determines that the end part of the tag paper is detected, in other words, paper shortage of the tag paper is detected. The condition under which the end part of the tag paper is detected may be the same as the condition under which the end part of the label paper is detected. If the paper end of the tag paper is detected, the conveyance control section 51 stops the feed motor 23 and the ribbon motor 24. Further, the light emission control section 52 stops the light emission of the light emitting elements 21a and 22a as shown in
Next, procedures of a light emission control processing are described.
The light emission control section 52 receives a print command via the host computer 30 or the keyboard 8 (Act S1). If the printing on the label paper is instructed in the print command (Yes in Act S2), the light emission control section 52 starts light emission control to the label paper (Act S3). In other words, the light emission control section 52 outputs the light emission signal that is continuously in the HI state to the transmission type sensor 21 as exemplified in
The end part detection section 54 determines whether or not the paper end of the label paper is detected on the basis of the output of the transmission type sensor 21 and the reflection type sensor 22 (Act S4). If the paper end of the label paper is not detected (No in Act S4), the processing returns to Act S3. If the paper end of the label paper is detected (Yes in Act S4), the conveyance control section 51 stops the feed motor 23 and the ribbon motor 24 to stop the conveyance of the label paper and the ink ribbon (Act S5). Further, the light emission control section 52 stops the light emission of the light emitting elements 21a and 22a (Act S6).
On the other hand, if the printing on the tag paper but not the printing on the label paper is instructed in the print command (No in Act S2), the light emission control section 52 starts light emission control to the tag paper (Act S7). In other words, the light emission control section 52 outputs the light emission signal that is continuously in the HI state to the reflection type sensor 22 as exemplified in
The end part detection section 54 determines whether or not the paper end of the tag paper is detected on the basis of the output of the transmission type sensor 21 and the reflection type sensor 22 (Act S8). If the paper end of the tag paper is not detected (No in Act S8), the processing returns to Act S7. If the paper end of the tag paper is detected (Yes in Act S8), the conveyance control section 51 stops the feed motor 23 and the ribbon motor 24 to stop the conveyance of the tag paper and the ink ribbon (Act S9). Further, the light emission control section 52 stops the light emission of the light emitting elements 21a and 22a (Act S10).
In the foregoing description, the transmission type sensor 21 and the reflection type sensor 22 respectively include the light receiving element 21b and the light receiving element 22b and detect transmitted light or reflected light; however, the constitution of the sensor is not limited to this. For example, the transmission type sensor 21 and the reflection type sensor 22 may share one light receiving element; on the contrary, each sensor may use two or more sensors.
The program executed by the label printer 100 of the present embodiment is incorporated into the ROM in advance to be provided. The program executed by the label printer 100 of the present embodiment may be recorded in a computer-readable recording medium such as a CD-ROM, a FD (Flexible Disk), a CD-R, a DVD (Digital Versatile Disk) and the like in the form of installable or executable file to be provided.
Furthermore, the program executed by the label printer 100 of the present embodiment may be stored on a computer connected with a network such as the Internet and downloaded via the network to be provided. Further, the program executed by the label printer 100 of the present embodiment may be provided or distributed via the network such as the Internet.
While certain embodiments have been described, these embodiments have been presented by way of example only, and are not intended to limit the scope of the invention. Indeed, the novel embodiments described herein may be embodied in a variety of other forms; furthermore, various omissions, substitutions and changes in the form of the embodiments described herein may be made without departing from the spirit of the invention. The accompanying claims and their equivalents are intended to cover such forms or modifications as would fall within the scope and spirit of the invention.
As stated above, in the foregoing embodiment, the light emission control for switching the single light emission period in which the light emitting element of the sensor at one side emits the light to carry out the position detection and the both light emission period in which the light emitting elements of both the transmission type sensor and the reflection type sensor emit the light to detect the paper end is carried out. In this way, both the improvement of the detection precision of the printing position and the improvement of the detection precision of the paper end can be realized.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2016-135006 | Jul 2016 | JP | national |
