JPH09141963A - Printer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a stabilized print while decreasing the number of components. SOLUTION: A platen 9 is disposed farther in the upstream of a medium flow than a position facing a print head 1 and provided with a light emitting element 11. A ribbon protector 5 disposed oppositely to the light emitting element 11 is provided with a light receiving element 12 for delivering a signal upon receiving a light. When the print head 1 is shifted and the light emitting element 11 faces the light receiving element 12, a control section receives a signal from the light receiving element 12 and recognizes arrival of the print head 1 at home position. When a medium, being carried to a printing part, reaches the light emitting element 11 and light receiving element 12 facing each other and intercepts the light emitted from the light emitting element 11, the controller receives receives a signal indicative of intersection of light and recognizes the arrival of the medium at a reference position.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printer.

[0002]

2. Description of the Related Art In a conventional printer, a carriage frame is movably provided so as to face a platen, and a print head is mounted on the carriage frame. A ribbon protector for guiding the ink ribbon is provided on the carriage frame at a position facing the platen. The carriage and the ribbon protector form a print head moving member.

A pulse motor is connected to the carriage frame to move the carriage frame in a state of facing the platen. The number of pulses required for the movement of the carriage frame is given to this pulse motor from the control section, and the pulse motor is driven thereby.

A sensor bracket is provided on the carriage frame, and a home position sensor is provided on a guide formed on the frame at a position where the carriage frame can be detected. There is. When the sensor bracket is detected during the initial operation, this home position sensor sends a signal to the control portion to indicate that the print head has reached the reference position (home position).

A pulse mode for moving the carriage frame
The drive amount of the printer and the moving distance of the carriage frame due to the drive amount are always constant, and the print head moves to the print start position after the carriage frame detects the home position sensor. Since the number of pulses required by the pulse motor can be obtained by calculation, when the home position sensor detects that the carriage frame has been detected, the control unit causes the home unit to detect the carriage frame. The number of pulse modes required to move the carriage frame from the position sensor to the print start position.
Control to give a pulse to the computer.

As a result, it becomes possible to oppose the print start line to the print head.

Although the medium is conveyed to the print head for printing, the printer is provided with a plurality of conveyance roller pairs in order to convey the medium to the print head. A driving force is applied from the pulse motor to the transport roller pair, and the pulse number required for transporting the medium is applied to the pulse motor from the control unit so that it is driven. Has become.

The guide formed between the print head and the transport roller immediately in front of the print head (upstream side in the medium transport direction) and at a distance from the print head is
A position detection sensor that detects that the medium has been conveyed to the reference position is provided. Transport roll for transporting media
The number of pulses required by the pulse motor from the time the medium is detected by the position detection sensor to the time it is conveyed to the print head, and the amount of rotation of the roller and the distance that the medium is conveyed by the amount of rotation are always constant. Is determined in advance, the control unit recognizes the position of the medium when the position detection sensor detects that the medium is detected, and conveys the medium from the position detection sensor to the print start position. The pulse motor is controlled so that the required number of pulses is given to the pulse motor.

As a result, it becomes possible to make the line to start printing face the print head.

In the above printer, when printing is performed on a medium, when the power is turned on, first, the carriage frame is moved.
Perform initial operation. And the carriage frame
When the home reaches the home position sensor and is detected,
A signal indicating the detection is transmitted to the control unit. Upon receiving this signal, the control unit recognizes the position of the print head. Then, a gap is secured between the side frame of the pretan and the end of the print area, and the print head is positioned from the home position to the print start position before the medium is conveyed to the print section. The required number of pulses is calculated and given to the pulse motor so that the print head faces the print start position of the medium. As a result, the printing start position of the medium in the column direction is positioned.

When the medium is transported from the upstream side of the medium transport to the print head by the transport roller and is transported to the reference position, the medium is detected by the position detection sensor. Then, a signal indicating the detection is transmitted to the control unit. In response to this signal, the control unit gives the pulse motor the number of pulses (predetermined) required to convey the medium to the print start position so that the print head faces the print start position of the medium. . As a result, the printing start position of the medium in the row direction is positioned.

[0012]

In the above-mentioned conventional printer, rubber is used as the material of the transport roller for transporting the medium, but the rubber expands and contracts under the influence of temperature. The diameter of the carrier roller changes. That is, the transport amount of the medium changes due to the temperature change. However, after the position sensor detects the medium, the pulse mode
The number of pulses applied to the data does not change. Therefore, when the diameter of the transport roller changes, the distance that the medium is transported changes in proportion to the diameter of the transport roller. The difference between the distance that should be conveyed and the distance that is actually conveyed becomes larger as the distance from the position detection sensor to the print start position of the print head becomes longer.

Further, a slight slip occurs between the conveying roller pair and the medium when the medium is conveyed. The deviation of the conveying distance due to the slip causes the medium to be positioned at the print start position of the print head. This is an error in the transport distance at that time.

The position detection sensor is provided not in front of the print head but in the guide for easy mounting, and there is a certain distance between the guide and the print head. -When affected by the change in the diameter of the roller and the slip between the transport roller and the medium, there will be a difference between the distance that should be transported and the distance that is actually transported, and the position where you want to start printing. However, there was a problem that printing could not be started and printing misalignment might occur significantly.

Further, two pairs of detection sensors, a position detection sensor and a home position sensor, are provided so that the printing can be started from a predetermined position. There is a problem that the number of necessary parts such as a sensor and a circuit used for detection of the detection sensor increases, resulting in an increase in cost.

[0016]

In order to solve the above-mentioned problems, the solution means provided by the present invention is such that a print head stacked on a print head moving member provided movably opposite to a platen, When the printer reaches the home position, it recognizes the position of the print head, and when the medium reaches the reference position, the printer recognizes the position of the medium. A light emitting portion or a light receiving portion for transmitting a signal depending on the presence or absence of light is provided, and a print head moving member is provided at a position facing the light emitting portion or the light receiving portion, and the light emitting portion or the signal depending on the presence or absence of light. When the print head moving mechanism moves and receives a signal from the light receiving unit, it is recognized that the print head has reached the home position, and During transport to the shaped portion, when receiving the signal from the light receiving portion, it is provided with a recognizing controller that the medium has reached the reference position.

Since the light emitting portion and the light receiving portion necessary for detecting the medium are near the print head, even if there is a difference between the distance at which the medium should be conveyed and the distance at which the medium is actually conveyed,
The difference is small. Further, since the light emitting portion and the light receiving portion are provided on the platen and the print head moving member, a pair of detection sensors are provided for detecting the position of the print head and the detection sensor for recognizing the position of the medium. Can also be used as

[0018]

Embodiments of the present invention will be described with reference to the drawings. Elements common to the drawings are denoted by the same reference numerals.

First Embodiment FIG. 1 is a schematic perspective view showing a printing unit according to the first embodiment of the invention, and FIG. 2 is a schematic side view showing the printing unit according to the first embodiment of the invention. . In FIGS. 1 and 2, a carriage frame 2 on which a print head 1 is mounted is slidably mounted along a guide shaft 3 in a direction indicated by an arrow AB in a printing section for printing on a medium 16. Has been. The carriage frame 2 is provided with a ribbon protector 5 for guiding the ink ribbon 4 on the pin side (not shown) of the print head. A guide beam 6 for guiding the carriage frame 2 is provided above the carriage frame 2.
Guide rollers 7a, 7b engaged with the carriage frame 2 are rotatably provided with respect to the carriage frame 2.

A head cable 8 is connected to the print head 1, and a drive command for printing is transmitted from the control unit described later through the head cable 8.

The carriage frame on the pin side of the print head 1
A platen 9 is provided so as to face the frame 2. A groove 10 is formed on the platen 9 upstream of the pin protruding position of the print head 1 in the transport direction. The position where the groove 10 is formed is a position near the print head 1 outside the pin projection position of the print head 1 from the pin projection position of the print head 1 and for supporting the platen 9. A frame (not shown) provided on both side surfaces of the platen 9.
This is a position that is a certain distance away from the system and through which a medium of the minimum medium width used in the printer always passes. The position where the groove 10 is formed is the reference position when the medium 16 is conveyed to the printing section.

A light emitting element 11 as a detection sensor is provided on the back surface of the platen 9 so that the light emitting portion fits in the groove 10.
The light emitting portion is attached so as to face the carriage frame 2 side. On the other hand, also in the ribbon protector 4, a groove 13 is formed at a position separated from the pin projecting position of the print head 1 by the same distance as the groove 10 in the upstream side in the medium carrying direction. A light receiving element 12 is attached to the back surface of the ribbon protector 5 so that the light receiving portion fits in the groove 13. Further, the light emitting element 11 and the light receiving element 12 respectively have sensor cables 14 and 15 connected to the control unit.
Is connected, and the detection result is transmitted to the control unit. The sensor cable 15 is wired together with the head cable 8 and connected to the controller.

As shown in FIG. 2, a transport roller for transporting the medium 16 to the printing unit is located upstream of the printing unit in the medium transport direction.
La pairs 17 are provided. Further, a guide pair 19 is provided between the transport roller pair 17 and the transport roller pair 17, and by the transport roller pair 17 and the guide pair 19,
A transport path 18 is formed, and the medium 16 is guided through the transport path 18.

Next, a control system relating to the printing unit of the printer having the above-mentioned configuration will be described. FIG. 3 is a block diagram showing a control system according to the first embodiment of the invention. The printer is provided with a control unit 20 that controls the entire apparatus. An interface 22 to which print contents are transmitted from a higher-level device 21 via a line is connected to the control unit 20, and the control unit 2 is connected via the interface.
0 receives the print content and print position. Further, the light emitting element 11 and the light emitting element 12 are connected to the control section 20, the light emitting element 11 causes the light emitting section to emit light according to an instruction from the control section, and the light receiving element 12 receives light from the light receiving element 11. When the medium 16 blocks the light from the light-emitting element 11 and the light-receiving element 12 stops receiving the light from the light-emitting element 11, the light-receiving element 12 stops receiving light from the light-receiving element 12 as well as sending a signal to the control section 20 to inform the control section 20. A signal for notifying that the light from the light emitting element 11 is no longer received is sent to. Upon receiving this signal, the control unit 20 controls the print head 1
Recognize that it has reached the home position and that the medium 16 has reached the reference position. The light emitting element 11
The light receiving element 12 has two roles of a conventional position detecting sensor and a home position sensor.

A drive circuit 35 and a drive circuit 36 are also connected to the control section 20, the drive circuit 35 is connected to the pulse motor 23, and the drive circuit 36 is connected to the pulse motor 24.
It is connected to the. In the drive circuit 35 and the drive circuit 26,
The number of pulses sent from the control unit 20 to the pulse motors 23 and 24 is transmitted. The drive circuit 3 receives this pulse number.
5 and the drive circuit 36 give a pulse to the pulse motors 23 and 24, and the pulse motors 23 and 24 are given by the given number of pulses.
24 is driven.

The pulse motor 23 is connected to the carrier roller pair 17 and rotates the carrier roller pair 17. on the other hand,
The pulse motor 24 is connected to the carriage frame 2 and moves the carriage frame 2 in the directions of arrows AB. That is, the pulse motor 23 and the pulse motor 24
Is to convey the medium 16 or move the print head 1.

A drive circuit 25 is also connected to the control unit 20, and the drive circuit 25 is connected to the print head 1. The control unit 20 controls the drive circuit 25 based on the print content received from the higher-level device 21, causes a pin (not shown) of the print head 1 to project, and prints the print content on the medium 16.

Next, the operation for printing by the printer having the above configuration will be described.

In FIG. 1, FIG. 2 and FIG. 3, after the power is turned on and before the printing is started, first, the initial operation is performed to set the home position of the print head 1, whereby the home position is set. The control unit 20 is set to secure a gap between the side frame (not shown) of the printer and the end of the print area and to position the print head 1 at the print start position. Therefore, the control unit 20 drives the pulse motor 24 via the drive circuit 35 to slide the carriage frame 2 along the guide shaft 3 and the guide beam 6 in the arrow A direction.

When moving to a predetermined position, the light emitting element 11 and the light receiving element 12 face each other, and a signal is sent from the light receiving element 12 to the control section 20. Upon receiving this signal, the control unit 20 recognizes that the print head 1 has reached the home position, that is, the position of the print head 1, and detects the moving distance of the carriage frame 2, that is, the pulse of the pulse motor 24. Set to control the number. Thus, a gap can be secured between the side frame and the end of the print area. At the same time, the control unit 20 can control how many pulses the print head 1 is sent from the home position to reach the print start position.

Next, the operation of transporting the medium 16 to the printing section will be described. At that time, the control unit 20 controls the light emitting element 11 and the light receiving element 12 so as to be positioned to face each other.
The carriage frame 2 is moved and stopped at that position. When the medium 16 is conveyed to the printing section by the conveying roller pair 17 while being guided by the guide pair 19 in the conveying path 18, the medium 16 reaches the light emitting element 11 and the light receiving element 12, and the light of the light emitting element 11 is emitted. Block off. Then, the signal is transmitted to the control unit 20, and the control unit 20 recognizes that the medium 16 has reached the reference position.

Based on the recognition result, the control unit 20
The number of pulses (predetermined) required to convey the medium 16 from the reference position to the print start position is given to the pulse motor 23 via the drive circuit 35. At this time, for example, it is assumed that the diameter of the transport roller pair 17 has changed due to the influence of temperature, and that the slip has occurred between the transport roller pair 17 and the medium 16. Therefore, the pulse motor 23 preset to convey the medium 16 to the print start position is used.
There will be a difference between the transport distance obtained from the number of pulses and the distance that the medium 16 is actually transported.

However, the light emitting element 11 and the light receiving element 12 are
Since the distance from the reference position to the print start position is short in the vicinity of the print start position on the medium 16, the pulse mode preset for transporting the medium 16 from the reference position to the print start position is set. Even if there is a difference between the transport distance obtained from the number of pulses of the output signal 23 and the actual transport distance of the medium 16, the difference can be minimized, and the print start position deviation can be reduced. Can be kept to a minimum.

When the print start position of the medium 16 is positioned on the print head 1, printing is started, and the medium 16 is sequentially ejected from the printer from the portion where the printing is completed. As described above, in the first embodiment, the role of the position detection sensor and the home position sensor is performed by the pair of detection sensors. Therefore, the number of parts required for the detection sensor to perform the detection operation is reduced. You can

Further, since the light emitting element 11 and the light receiving element 12 for detecting the medium 16, that is, the conventional position detecting sensor are much closer to the print head 1 than the conventional one, the carrier roller pair 17 due to a temperature change. It is possible to minimize the shift in the print start position due to the change in the diameter of the sheet and the slip between the transport roller pair 17 and the medium 16.

Although the light emitting element 11 is attached to the platen 9 and the light receiving element 12 is attached to the ribbon protector 5, the light receiving element 12 may be attached to the platen 9 and the light emitting element 11 may be attached to the ribbon protector 5. .

Second Embodiment Next, a second embodiment of the present invention will be described with reference to the drawings. The same parts as those in the first embodiment are designated by the same reference numerals and the description thereof will be omitted. FIG. 4 is a schematic perspective view showing a printing unit according to the second embodiment of the invention, and FIG. 5 is an explanatory view showing a relationship between a light refraction member, a light emitting element, and a light receiving element according to the second embodiment of the invention. . This embodiment is different from the first embodiment in that not only the light emitting element and the light receiving element but also the light refracting member is used to serve as a conventional position detecting sensor and a home position sensor. is there.

More specifically, referring to FIG. 4 and FIG.
In the embodiment, the light refracting member 25 is attached to the platen 9 where the issuing element 11 is attached, and the light refracting member 26 is attached to the ribbon protector 5 where the light receiving element 12 is attached. Has been. The positions where the grooves 10 and 13 are formed are the same as those in the first embodiment, and therefore, except that the light refracting members 25 and 26 are added to the members that serve as the detection sensor, This is similar to the first embodiment.

On the side frame (not shown) of the printer,
A substrate 27 is attached, and when light is emitted to the substrate 27, the light is reflected by the reflection surface 2 of the light refraction member 25.
The light emitting element 28 is attached to a position corresponding to 5a. A light receiving element 29 is attached to the substrate 27 at a position where the light emitted from the light refracting member 26 strikes. That is, when the light refraction member 25 and the light refraction member 26 face each other, the light emitted from the light emitting element 28 emits light.
It is refracted when it hits the reflection surface 25 a of the light and enters the light refraction member 26. Then, it hits the reflecting surface 26 a of the light refracting member 26 and is refracted, emitted from the light refracting member 26, and reaches the light receiving element 29.

Sensor cables 30, 31 are connected to the light emitting element 28 and the light receiving element 29, respectively.
The sensor cables 30 and 31 are connected to the control unit 20. As a result, the control unit 20 controls the light emitting element 28 and the light receiving element 29. Note that this point is also the same as that of the first embodiment.

In the printing operation of the printer having the above structure, the photorefractive members 25 and 26 are newly added as detection sensors.
Since the third embodiment is the same as the first embodiment except that is added, the description thereof will be omitted.

As described above, in the second embodiment, in addition to the effects of the first embodiment, the side frame of the printer is
The light emitting element 28 and the light receiving element 29 are attached to the board, so that the light emitting element 2 is provided inside the mechanism.
No wiring is required for 8 and the light receiving element 29. As a result, since it is not necessary to consider the wiring, the structure inside the mechanism can be simplified accordingly.

The light emitting element 28 and the light receiving element 29 are attached to the substrate 27 by screws (not shown).
When exchanging the light emitting element 28 and the light receiving element 29, it is necessary to remove the screws. If the printing section has the light emitting element 28 and the light receiving element 29, the entire unit of the printing section must be removed from the printer main body and the screws must be removed. However, the light emitting element 28 and the light receiving element 29 are not provided inside the printing section. Instead, it is mounted on the side, so there is no need to remove the entire unit when replacing. Therefore, the light emitting element 28 and the light receiving element 29 can be easily replaced.

As with the first embodiment, there is no problem even if the mounting positions of the light emitting element 28 and the light receiving element 29 are reversed. Furthermore, in the above-described first and second embodiments, the grooves 10 and 13 may be holes.

Third Embodiment Next, a third embodiment of the present invention will be described with reference to the drawings. The same parts as those in the first embodiment are designated by the same reference numerals and the description thereof will be omitted. FIG. 6 is a schematic perspective view showing a printing unit in the third embodiment of the invention, FIG. 7 is a block diagram showing a control system in the third embodiment of the invention, and FIG. 8 is a third embodiment of the invention. 3 is a perspective view showing a ribbon protector in FIG. This embodiment is different from the first and second embodiments in that
The recognition mark that reflects light in a certain form and the reflection sensor that receives the light serve as a conventional position detection sensor and a home position sensor.

More specifically, in FIG. 6, in the first embodiment, the reflection sensor 32 is attached to the platen 9 at the location where the issuing element 11 was attached.
As shown in FIG. 7, the reflection sensor 32 is connected to the control unit 20, and changes the signal to the control unit 20 according to the shape of the light received by the reflection sensor 32 or the presence / absence of the light. The change in the signal from the reflection sensor 32 identifies what the reflection sensor 32 is detecting.

Further, as shown in FIG. 8, on the back surface of the ribbon protector 4 at a position facing the reflection sensor 32,
A recognition mark 33 is provided which reflects the light in a certain form when the light hits it. A reflection sensor 32 is attached to the recognition mark 33.
The light is reflected in a certain form when the light of (1) hits, and the reflection sensor 32 sends a signal to the control unit 20 when receiving the light of this form. Upon receiving this signal, the control unit 20 recognizes that the print head 1 has moved to a predetermined position.

Further, when the shape of the light returning to the reflection sensor 32 changes during the transportation of the medium 16 to the printing unit, the control unit 20.
Signal is sent to. As a result, the control unit 20 recognizes that the medium 16 has been conveyed to the reference position. Since the position where the groove 10 is formed is the same as that of the first embodiment, it is the same as that of the first embodiment except that the member serving as the detection sensor is changed. .

Next, the operation for printing by the printer having the above configuration will be described. FIG. 9 is an explanatory view showing the relationship between the reflection sensor and the recognition mark in the third embodiment of the invention, and FIG. 10 is a perspective view showing the medium in the embodiment of the invention.

In FIG. 6, after the power is turned on and before the printing is started, first, the initial operation is performed, and the position of the print head 1 is recognized by the control unit 20, whereby the side frame (not shown) of the printer is detected. A control unit 20 is set to secure a gap between the frame and the end of the print area and position the print head 1 at the print start position. Therefore, the control unit 20 drives the pulse motor 23 via the drive circuit 35 to slide the carriage frame 2 in the direction of arrow A along the guide shaft 3 and the guide beam 6.

When it moves to a predetermined position, as shown in FIG. 9, the reflection sensor 32 and the recognition mark 33 face each other, the reflection sensor 32 detects the recognition mark 33, and the reflection sensor 32 is detected. A signal is transmitted from the control unit 20 to the control unit 20. Control unit 2
In response to this signal, 0 recognizes that the print head 1 has reached the home position and sets the pulse number of the pulse motor 23.

Next, the operation of transporting the medium 16 to the printing section will be described. At this time, the carriage frame 2
It may be stopped at any position. Medium 16 is transport path 18
When the medium 16 is conveyed to the printing section by the conveying roller pair 17 while being guided by the guide pair 19, the medium 16 reaches the reflection sensor 32 and the shape of the light returning to the reflection sensor 32 changes. That is, the reflectance changes. Thereby, the signal is transmitted to the control unit 20, and the control unit 20 recognizes that the medium 16 has reached the reference position.

Based on the recognition result, the control unit 20
The number of pulses (predetermined) required to convey the medium 16 from the reference position to the print start position is given to the pulse motor 23 via the drive circuit 35. Thereby,
The medium 16 is conveyed to a position where the print start position faces the print head 1, and printing is performed from there.

In the third embodiment, the recognition mark 33 may be embossed or a single color label as long as it can be distinguished from the back surface of the other ribbon protector 5. Further, as shown in FIG. 10, a recognition mark 34 for identifying the medium is printed at a position facing the reflection sensor 32 on the back surface of the medium 16 while changing the type of the medium 16 for printing. If the recognition mark 34 is detected and the control unit 20 recognizes the type of the medium 16 according to the change in the signal from the reflection sensor 32 due to the difference in the recognition mark 34, Not only the position of the medium 16 at the time of transportation can be recognized, but also the type of the medium 16 can be automatically recognized on the side of the apparatus, and the operator's labor can be saved.

The type of the medium 16 may be recognized by changing the position of the recognition mark 34 in the carrying direction without changing the recognition mark 34.

In the above third embodiment, in addition to the effects of the first embodiment, the ribbon protector 5 is merely provided with the recognition mark 33, and wiring is required and parts are attached. Since it is not necessary, the configuration of the print head moving member can be greatly simplified.

Further, since the reflection sensor 32 is used, the recognition mark 34 and the reflection sensor 32 have to face each other only when recognizing the position of the print head 1. Therefore, when transmitting that the medium 16 has been conveyed to the reference position to the control unit 20, only the medium 16 needs to be positioned with respect to the reflection sensor 32. Therefore, the stop position of the carriage frame 2 can be arbitrarily set, so that the medium 16
If the ribbon protector 5 is positioned at a position where the curl of the medium 16 tends to occur when the curl of the medium 16 is conveyed to the printing unit, and the curl of the medium 16 is pressed by the side surface of the ribbon protector 5, 5 can serve as a conveyance guide.

Further, as in the first and second embodiments, there is no problem even if the attachment positions of the reflection sensor 32 and the recognition mark 33 are reversed. With such a configuration, the reflection sensor 32 is in operation during the operation of conveying the medium 16 to the printing unit.
The position of the ribbon protector 5 is set so that the medium 16 can be positioned at a position where the medium 16 can be detected.

[0059]

Since the present invention is configured as described above, it has the following effects. On the platen upstream of the medium transport direction from the position facing the print head,
A light emitting portion or a light receiving portion for transmitting a signal depending on the presence or absence of light is provided, and a print head moving member is provided at a position facing the light emitting portion or the light receiving portion, and the light emitting portion or the signal depending on the presence or absence of light. When the print head moving mechanism moves and receives a signal from the light receiving unit, it recognizes that the print head has reached the home position, and when the medium is conveyed to the printing unit, When a signal from the light receiving unit is received, a control unit that recognizes that the medium has reached the reference position is provided, so that the light emitting unit and the light receiving unit necessary for detecting the medium are near the print head. Even if there is a difference between the distance that the medium should be transported and the distance that the medium is actually transported, the difference is small. Therefore, it is possible to minimize the deviation of the print start position and perform stable printing.

Since the light emitting portion and the light receiving portion are provided on the platen and the print head moving member, a pair of a detection sensor for recognizing the position of the print head and a detection sensor for recognizing the position of the medium are provided. Can also be used as the detection sensor. Therefore, the number of parts required for the detection sensor to perform the detection operation can be reduced.

[Brief description of the drawings]

FIG. 1 is a schematic perspective view showing a printing unit according to a first embodiment of the invention.

FIG. 2 is a schematic side view showing a printing unit according to the first embodiment of the invention.

FIG. 3 is a block diagram showing a control system in the first embodiment of the invention.

FIG. 4 is a schematic perspective view showing a printing unit according to a second embodiment of the invention.

FIG. 5 is an explanatory diagram showing a relationship among a light refraction member, a light emitting element, and a light receiving element according to the second embodiment of the invention.

FIG. 6 is a schematic perspective view showing a printing unit according to a third embodiment of the invention.

FIG. 7 is a block diagram showing a control system according to a third embodiment of the invention.

FIG. 8 is a perspective view showing a ribbon protector according to a third embodiment of the invention.

FIG. 9 is an explanatory diagram showing a relationship between a reflection sensor and a recognition mark according to the third embodiment of the invention.

FIG. 10 is a perspective view showing a medium according to a third embodiment of the invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 print head 2 carriage frame 5 ribbon protector 9 platen 11 light emitting element 12 light receiving element 16 medium 20 control section 25 light refracting member 26 light refracting member 28 light emitting element 29 light receiving element 32 reflection sensor 33 recognition mark 34 recognition mark Ku

Claims (4)

[Claims] 1. When a print head stacked on a print head moving member, which is movably provided so as to face the platen, reaches a home position, the position of the print head is recognized and the medium is used as a reference. When a printer recognizes the position of the medium when it reaches the position, a light emitting unit or a light receiving unit that sends out a signal according to the presence or absence of light is provided on the platen upstream of the position facing the print head in the medium conveying direction, and printing is performed. The head moving member is provided with a light emitting unit or a light receiving unit for transmitting a signal depending on the presence or absence of light at a position facing the light emitting unit or the light receiving unit, and the print head moving mechanism moves to move from the light receiving unit. When the signal is received, it is recognized that the print head has reached the home position, and when the signal is received from the light receiving unit when the medium is being conveyed to the printing unit, the medium is at the reference position. A printer provided with a control unit for recognizing arrival. 2. When a print head stacked on a print head moving member movably provided facing the platen reaches a home position, the print head position is recognized and the medium is used as a reference. When reaching the position, in a printer that recognizes the position of the medium, a light refraction member is provided on the platen upstream of the medium conveyance direction from the position facing the print head, and is a print head moving member that faces the light refraction member. A light refraction member is provided at a position, and a light emitting element that irradiates one of the light refraction members with light is provided on the same plate as the light emitting element. When the print head moving mechanism moves and the light receiving element that sends out a signal through the received light and sends out a signal and the light is no longer received, the print head moves to the home And a control unit that recognizes that the medium has reached the reference position when it receives a signal from the light receiving unit while the medium is being conveyed to the printing unit. Printer. 3. When the print head stacked on a print head moving member movably provided facing the platen reaches the home position, the print head position is recognized and the medium is used as a reference. When the printer reaches the position, the printer that recognizes the position of the medium is provided with a recognition mark that reflects light in the form of a platen upstream of the position facing the print head in the medium transport direction.
Alternatively, a reflection sensor that emits light and receives the reflected light and sends a signal according to the presence or absence of the light or the shape of the light is provided, and the print head moving member is provided at a position facing the recognition mark or the reflection sensor. , A recognition mark that reflects light in a certain shape is provided, or a reflection sensor that emits light and receives the reflected light and sends a signal according to the presence or absence of light or the shape is provided. When it moves and receives the signal from the reflection sensor, it recognizes that the print head has reached the home position, and when the signal from the reflection sensor is received when the medium is conveyed to the printing unit, the medium moves to the reference position. And a control unit for recognizing that the printer has arrived. 4. The medium is provided with a recognition mark that reflects light in a different form for each type, and the control unit recognizes the type of the medium when receiving a signal from a reflection sensor. Printer.