PRINTING DEVICE AND PRINTING DEVICE CONTROL METHOD

The printing device includes a support section 17 for supporting a medium 99, a head 28 for ejecting liquid on a print region 19, a carriage 27 on which the head is mounted, a guide 25 for supporting the carriage, a motor for moving the carriage, a rotary encoder, a linear encoder 35 for detecting the position of the carriage, and a control section. The linear encoder has a linear scale 36 and a sensor 37, the linear scale has a first region S1 where slits 38 are positioned and a second region S2 where the slits are not positioned, and when the head faces the printing region, the sensor is positioned in the first region, and the length of the first region in one direction is equal to or longer than the length of the printing region in one direction.

The present application is based on, and claims priority from JP Application Serial Number 2022-080700, filed May 17, 2022, the disclosure of which is hereby incorporated by reference herein in its entirety.

BACKGROUND

1. Technical Field

The present invention relates to a printing device and a printing device control method.

2. Related Art

JP-A-9-234925 describes a printing device in which the ejection timing of liquid ejection by a head is controlled by a linear scale having a plurality of slits.

In such a printing device, the linear scale becomes longer as the size of the apparatus increases. When the linear scale is long, the positional accuracy of the slits is likely to decrease. This is because, as the linear scale becomes longer, it becomes more difficult to form the slits at uniform intervals over the entire length of the linear scale. Therefore, when the linear scale is long, the printing quality is likely to be degraded.

SUMMARY

A printing device that overcomes the above issues includes a support section configured to support a medium; a head configured to eject liquid onto a print region of the medium, the print region being a region of the medium that is supported by the support section; a carriage on which the head is mounted; a guide that supports the carriage and that extends in one direction; a motor configured to move the carriage along the guide between a home position and a return position; a rotary encoder for detecting a rotation angle of the motor; a linear encoder configured to detect a position of the carriage; and a control section, wherein the control section controls a position of the carriage based on output of the rotary encoder and controls ejection timing of liquid by the head based on output of the linear encoder, the support section faces the head by the carriage moving between the home position and the return position, the linear encoder includes a linear scale that extends in the one direction and that has a plurality of slits arranged in the one direction and a sensor that is attached to the carriage and that is configured to detect the slits, by movement of the carriage, the sensor moves over the linear scale between a first position and a second position, the first position is a position on the linear scale where the sensor is located when the carriage is located at the home position, the second position is a position on the linear scale where the sensor is located when the carriage is located at the return position, the linear scale includes, between the first position and the second position, a first region in which the plurality of slits are located and a second region in which the plurality of slits are not located, the sensor is located in the first region when the head faces the print region, and a length of the first region in the one direction is greater than or equal to a length of the print region in the one direction.

A printing device control method for overcoming the above issues is a printing device control method for a printing device including a support section configured to support a medium, a head configured to eject liquid onto a print region of the medium, the print region being a region of the medium that is supported by the support section, a carriage on which the head is mounted, a guide that supports the carriage and that extends in one direction, a motor configured to move the carriage along the guide between a home position and a return position, a rotary encoder for detecting a rotation angle of the motor, and a linear encoder configured to detect a position of the carriage, the support section faces the head by the carriage moving between the home position and the return position, the linear encoder includes a linear scale that extends in the one direction and that has a plurality of slits arranged in the one direction and a sensor that is attached to the carriage and that is configured to detect the slits, by movement of the carriage, the sensor moves over the linear scale between a first position and a second position, the first position is a position on the linear scale where the sensor is located when the carriage is located at the home position, the second position is a position on the linear scale where the sensor is located when the carriage is located at the return position, the linear scale includes, between the first position and the second position, a first region in which the plurality of slits are located and a second region in which the plurality of slits are not located, the sensor is located in the first region when the head ejects liquid at the print region, and a length of the first region in the one direction is longer than a length of the print region in the one direction, the printing device control method comprising: controlling position of the carriage based on output of the rotary encoder; controlling ejection timing of the liquid by the head based on output of the linear encoder; and when the sensor moves from the second region to the first region, output of the linear encoder is reset before the head ejects liquid to the printing region.

DESCRIPTION OF EMBODIMENTS

Hereinafter, an embodiment of a printing device will be described with reference to the drawings. The printing device is, for example, an ink jet printer that prints images such as characters or photographs by ejecting ink, which is an example of liquid, onto a medium such as paper or fabric. The printing device is, for example, a label printer.

Configuration of Printing Device

As shown inFIG.1, the printing device11includes a housing12. The printing device11includes a feeding section13. The feeding section13is configured to feed a medium99. The feeding section13is accommodated in the housing12, for example. The feed section13has a feed shaft14. The feeding shaft14rotatably holds a roll body100into which the medium99is wound. The feeding shaft14holds the medium99before it is printed on. The medium99is fed out from the feeding section13with rotation of the feeding shaft14. The feeding shaft14may be driven to rotate by a motor, or may be driven to rotate as the medium99is drawn out.

The printing device11includes a winding section15. The winding section15is configured to wind up the medium99. The winding section15is accommodated in the housing12, for example. The winding section15has a winding shaft16. Similarly to the feeding shaft14, the winding shaft16rotatably holds a roll body100. The winding shaft16holds the medium99after it has been printed on. The winding section15winds up the medium99as the winding shaft16rotates. The winding shaft16is driven to rotate by, for example, a motor.

The printing device11includes a support section17. The support section17supports the medium99. The support section17is accommodated in the housing12, for example. For example, the support section17supports the medium99from below. The support section17supports the medium99during the process from when the medium99is fed from the feeding section13to when the medium99is wound up by the winding section15.

The support section17has a support surface18. The support surface18is a surface of the support section17that comes into contact with the medium99. The support surface18faces upward in the support section17, for example. When the support section17is viewed from a position facing the support surface18, that is, when the support section17is viewed from above the support section17, the support surface18overlaps the medium99.

As shown inFIG.2, the support section17has two end sections with respect to one direction. The support section17has, for example, a first support end section17A and a second support end section17B with respect to the one direction. Specifically, the support section17has a first support end section17A and a second support end section17B with respect to a first direction A1. The first direction A1indicates a direction in which the medium99moves over the support section17. The first direction A1is a direction in which the support surface18extends. Of the two end sections, the first support end section17A is the one closer to a home position P1(to be described later). Of the two end sections, the second support end section17B is the one closer to a return position P2(to be described later).

As shown inFIG.1, a region of the medium99that is supported by the support section17is a print region19. In the printing device11, printing is performed on the print region19of the medium99. The print region19is the region of the medium99that overlaps the support section17when the support section17is viewed from a position facing the support surface18. In other words, the print region19overlaps the support surface18in a plan view of the support section17. The print region19is, for example, the entire region of the medium99supported by the support section17. The print region19is not limited to the entire region of the medium99supported by the support section17, and may be a portion of the region supported by the support section17. The print region19refers to a maximum region in which the printing device11can perform printing in a region supported by the support section17.

The printing device11may include an attraction section21. The attraction section21is configured to attract the medium99to the support section17. The attraction section21causes the medium99to cling to the support section17by, for example, sucking the medium99through the support section17. The attraction section21includes, for example, a suction pump. The attraction section21sucks the medium99through, for example, through-holes opened in the support surface18. By this, the medium99clings to the support surface18. The attraction section21may attract the medium99toward the support section17by generating static electricity, for example.

The attractive force of the attraction section21can be changed by, for example, controlling the suction force. For example, the attraction section21changes the attractive force in accordance with the transport of the medium99. For example, while the medium99is being transported, the attraction section21reduces the attractive force compared to when the transport of the medium99is stopped. While the medium99is being transported, the attraction section21relatively reduces the attractive force. By making the attractive force of the attraction section21relatively small while the medium99is being transported, the medium99easily moves over the support section17. While printing is being performed on the medium99, that is, when the transport of the medium99is stopped, the attraction section21relatively increases the attractive force. By making the attractive force of the attraction section21relatively large while the transport of the medium99is stopped, the position of the medium99on the support section17is less likely to be displaced.

The printing device11includes a transport section22. The transport section22is configured to transport the medium99. The transport section22is accommodated in the housing12, for example. The transport section22transports the medium99from the feeding section13toward the winding section15. The transport section22transports the medium99in the first direction A1over the support section17.

The transport section22transports the portion of the medium99that has passed over the support section17downward from the support section17. That is, the medium99on which printing has been completed is transported by the transport section22from the support section17further downward than the support section17.

The transport section22intermittently transports the medium99. That is, the transport section22repeats start of transport and stop of transport. While printing on the medium99is being executed, the transport section22stops transporting the medium99. While printing on the medium99is not executed, for example, when printing on the medium99is completed, the transport section22starts transporting the medium99. In the printing device11, printing on the medium99and transport of the medium99are alternately repeated.

The transport section22includes one or more transport rollers23. The transport rollers23are located, for example, in the housing12. The transport rollers23transport the medium99by rotating. The medium99winds around the transport rollers23. The transport rollers23may sandwich the medium99. The medium99is transported by the rotation of the transport rollers23. The transport rollers23include, for example, a roller driven to rotate by a motor. The transport rollers23are located lower than is the support surface18, for example.

The printing device11includes a drying section24. The drying section24is configured to dry the printed-on medium99. The drying section24dries the medium99during the process of the medium99being transported from the support section17to the winding section15. The drying section24is located, for example, in the housing12. For example, the drying section24is located immediately below the support section17. The drying section24includes, for example, a heater that heats the medium99. The drying section24may include a fan that blows a gas at the medium99. By this, the drying section24dries the medium99.

The printing device11includes a guide25. The guide25is housed in the housing12. The guide25is supported by, for example, a frame in the housing12. The guide25extends in one direction. For example, the guide25extends in one direction in a region above the support section17. The guide25is, for example, a rod elongated in one direction. The guide25extends, for example, in the first direction A1. The guide25may extend in a second direction B1. The second direction B1is a direction different from the first direction A1. The second direction B1is a direction intersecting the first direction A1in a plane along the support surface18. The second direction B1is a direction in which the support surface18extends. That is, the support surface18extends in the first direction A1and in the second direction B1.

The printing device11includes a printing section26. The printing section26is supported by the guide25. The printing section26is configured to print on the medium99. The printing section26performs printing on the medium99by ejecting liquid onto the medium99. The printing section26performs printing in the print region19. The printing section26is accommodated in the housing12, for example. The printing section26includes a carriage27and one or more heads28. The carriage27and the head28are located, for example, higher than the support section17.

The head28is mounted on the carriage27. The carriage27is configured to move relative to the medium99. The carriage27moves relative to the print region19. The carriage27moves in a region facing the support section17. The carriage27moves so as to pass through the print region19, as seen from a plan view of the support section17. For example, the carriage27moves in a region higher than the support section17.

The carriage27is supported by the guide25. The carriage27moves along the guide25. Therefore, the carriage27moves in the first direction A1, for example. Specifically, the carriage27reciprocates in the first direction A1. That is, the carriage27moves in the first direction A1and in the direction opposite thereto. Therefore, the carriage27moves in the direction in which the medium99moves on the support section17. Therefore, the printing device11is a so-called lateral printer.

The carriage27may be configured to move in the second direction B1. In this case, the guide25would extend in the second direction B1. When the guide25extends in the second direction B1, the printing device11is a so-called serial printer. In the serial printer, the carriage27reciprocates in the second direction B1. That is, in the serial printer, for example, the carriage27moves in the second direction B1and a direction opposite thereto.

As shown inFIG.2, the carriage27is displaced to a plurality of positions by moving along the guide25. The carriage27is displaced to a home position P1and to a return position P2by moving along the guide25. The carriage27moves between the home position P1and the return position P2. The carriage27is displaced by moving along the guide25to a reset position P3in addition to the home position P1and the return position P2. The home position P1, the reset position P3, and the return position P2are arranged in this order in the first direction A1.

The carriage27located at the home position P1is aligned with the support section17with respect to one direction. For example, the carriage27located at the home position P1and the support section17are arranged in this order in the first direction A1. The carriage27located at the return position P2is aligned with the support section17in the one direction. For example, the support section17and the carriage27located at the return position P2are arranged in this order in the first direction A1. Therefore, the carriage27passes over the print region19by moving between the home position P1and the return position P2. By the carriage27moving between the home position P1and the return position P2, the support section17faces the head28. The carriage27moves between the home position P1and the return position P2during printing, for example.

The home position P1is a position where the carriage27stands by. Normally the carriage27stands by at the home position P1. For example, while the printing section26does not perform printing on the medium99, the carriage27is positioned at the home position P1. The home position P1is, for example, a position upstream of the support section17in the first direction A1.

The return position P2is the position where the carriage27switches direction of movement during printing. For example, when the carriage27reaches the return position P2by moving in the first direction A1, the carriage27moves from the return position P2in a direction opposite to the first direction A1, that is, it returns. The return position P2is, for example, a position downstream of the support section17in the first direction A1.

The reset position P3is a position between the home position P1and the return position P2in one direction. When the carriage27is positioned at the reset position P3, the output of a linear encoder35(to be described later) is reset. The reset position P3is, for example, a position upstream of the support section17in the first direction A1. The reset position P3may be a position downstream of the support section17in the first direction A1.

A plurality of reset positions P3may be provided. For example, a reset position P3may be located at both a position upstream of the support section17in the first direction A1and at a position downstream of the support section17in the first direction A1.

The carriage27may be displaced to a flushing position by moving along the guide25. The flushing position is, for example, a position between the home position P1and the return position P2in one direction. The carriage27is displaced to the flushing position when the printing section26performs flushing. Flushing is the discharge of liquid that does not contribute to printing. Flushing is performed as needed, for example, before printing, during printing, or after printing. The flushing position is, for example, a position upstream of the support section17or downstream of the support section17in the first direction A1.

The carriage27may be configured to move not only within the region that has the home position P1and the return position P2as end sections, but also outside the region that has the home position P1and the return position P2as end sections. The carriage27may be displaced to a maintenance position located outside the region that has the home position P1and the return position P2as end sections. The maintenance position is, for example, a position upstream of the home position P1in the first direction A1or a position downstream of the return position P2in the first direction A1. The carriage27is displaced to the maintenance position when, for example, a user performs maintenance on the printing section26.

The carriage27has two ends with respect to one direction. The carriage27includes, for example, a first carriage end section27A and a second carriage end section27B in the first direction A1. Of the two ends, the first carriage end section27A is the one that is closer to the home position P1when the carriage27is located between the home position P1and the return position P2. Of the two ends, the second carriage end section27B is the one that is closer to the return position P2when the carriage27is located between the home position P1and the return position P2.

The head28has one or more nozzles. The head28ejects liquid from the nozzles. The head28ejects liquid onto the medium99supported by the support section17. Specifically, the head28ejects liquid to the print region19. The head28ejects liquid onto the medium99while transport of the medium99by the transport section22is stopped. Thus, an image is printed on the medium99.

The head28ejects, for example, a plurality of types of liquids. The head28ejects, for example, cyan ink, magenta ink, yellow ink, and black ink. The head28may eject a reaction liquid in addition to the ink. The reaction liquid is, for example, a liquid that promotes fixing of the ink to the medium99.

The head28moves with respect to the support section17together with the carriage27. The head28ejects liquid onto the medium99while moving together with the carriage27. Specifically, the head28ejects liquid onto the medium99while moving in one direction together with the carriage27. For example, the head28ejects liquid onto the medium99while moving in the first direction A1, or in the opposite direction thereof, together with the carriage27. In the serial printer, for example, the head28ejects liquid onto the medium99while moving in the second direction B1, or in the opposite direction thereof, together with the carriage27.

The head28has two ends with respect to one direction. The head28has, for example, a first head end section28A and a second head end section28B with respect to the first direction A1. Of the two end sections, the first head end section28A is the end section closer to the home position P1in a state where the carriage27is positioned between the home position P1and the return position P2. Of the two end sections, the second head end section28B is the end section closer to the return position P2in a state where the carriage27is positioned between the home position P1and the return position P2.

The width of the head28is, for example, equal to the width of the medium99or greater than the width of the medium99. In other words, the head28is, for example, a line head capable of simultaneously ejecting liquid over the entire width of the medium99. Accordingly, the head28can eject liquid to the entire region of the print region19only by moving once in the first direction A1, or in the opposite direction thereof, together with the carriage27.

The width of the head28may be smaller than the width of the medium99. In this case, the head28can eject liquid over the entire width of the medium99by moving in both the first direction A1and in the second direction B1. For example, the carriage27moves in the second direction B1together with the guide25. Alternatively, a guide extending in the second direction B1may be provided separately from the guide25, and the head28may be moved in the second direction B1along this guide. By this, the head28prints over the entire print region19. When the guide25extends in the second direction B1, that is, when the printing device11is a serial printer, the carriage27moves in the second direction B1.

The printing section26performs, for example, unidirectional printing on the medium99. Unidirectional printing is a printing method in which a single movement direction of the carriage27accompanies ejection of liquid to the medium99. In unidirectional printing, the printing section26ejects liquid onto the medium99, for example, as it moves in either the first direction A1or in the opposite direction. That is, unidirectional printing is a printing method in which, when the carriage27reciprocates with respect to the medium99, liquid is ejected by the head28in either the forward path or in the return path.

The printing section26may perform bidirectional printing on the medium99. Bidirectional printing is a printing method in which a plurality of movement directions of the carriage27accompany ejection of liquid to the medium99. In bi-directional printing, for example, the printing section26ejects liquid as it moves in the first direction A1and in the opposite direction. That is, bidirectional printing is a printing method in which, when the carriage27reciprocates with respect to the medium99, liquid is ejected by the head28in both the forward path and in the return path.

The printing device11may include a flushing receiver29. The flushing receiver29is a member that receives liquid from flushing of the head28. By flushing, clogging of the nozzle is suppressed. The flushing receiver29is aligned with the support section17in one direction. For example, the flushing receiver29is located upstream of the support section17in the first direction A1. The flushing receiver29may be located downstream of the support section17in the first direction A1. The flushing receiver29faces the head28when the carriage27is located at the flushing position.

The flushing receiver29has two ends with respect to one direction. The flushing receiver29has, for example, a first receiving end section29A and a second receiving end section29B. Of the two end sections, the first receiving end section29A is the end section closer to the home position P1. Of the two end sections, the second receiving end section29B is the end section closer to the return position P2.

As shown inFIG.1, the printing device11includes a motor31. The motor31is coupled to the carriage27. The motor31moves the carriage27along the guide25. For example, the motor31moves the carriage27along the guide25between the home position P1and the return position P2.

The printing device11includes a rotary encoder32. The rotary encoder32detects a rotation angle of the motor31. The position of the carriage27is detected by the output of the rotary encoder32.

The printing device11includes a control section33. The control section33integrally controls the printing device11. The control section33controls, for example, the attraction section21, the transport section22, the printing section26, and the like. The control section33controls transport of the medium99and printing on the medium99. The control section33alternately executes transport of the medium99and printing on the medium99.

The control section33controls the movement of the carriage27based on the output of the rotary encoder32. For example, the control section33detects that the carriage27is positioned at the home position P1based on the output of the rotary encoder32. For example, the control section33detects that the carriage27is positioned at the return position P2based on the output of the rotary encoder32. For example, the control section33detects that the carriage27is positioned at the reset position P3based on the output of the rotary encoder32. For example, the control section33detects that the carriage27is located at the flushing position and located at the maintenance position, based on the output of the rotary encoder32. Therefore, the home position P1, the return position P2, the flushing position, and the maintenance position are positions determined based on the output of the rotary encoder32.

The control section33controls the ejection timing of liquid by the head28based on the output of the linear encoder35. Specifically, the control section33controls ejection timing of liquid by the head28with reference to the reset position P3based on the output of the linear encoder35.

The control section33may be constituted by one or more processors that execute various processes in accordance with computer programs. The control section33may be configured by one or more dedicated hardware circuits such as an application specific integrated circuit that executes at least a portion of the various processes. The control section33may be configured by a circuit including a combination of a processor and a hardware circuit. The processor includes a CPU and memory such as RAM and ROM. The memory stores program code or instructions configured to cause the CPU to perform operations. The memory, that is, the computer-readable medium, includes any readable medium that can be accessed by a general purpose or special purpose computer.

As shown inFIG.2, the printing device11includes the linear encoder35. The linear encoder35is configured to detect the position of the carriage27. The linear encoder35includes a linear scale36and a sensor37. The linear encoder35detects the position of the carriage27by the sensor37reading the linear scale36.

The linear scale36extends in one direction. The linear scale36extends parallel to the guide25. The linear scale36extends, for example, in the first direction A1. The linear scale36has a plurality of slits38. The slits38are arranged in one direction. The position of the carriage27is detected by the sensor37reading the slits38.

The linear scale36has a movement region SA. The movement region SA is a region in which the sensor37moves over the linear scale36. The length of the movement region SA is, for example, shorter than the entire length of the linear scale36in one direction. The length of the movement region SA may coincide with the entire length of the linear scale36in one direction. When the length of the movement region SA is shorter than the entire length of the linear scale36, then, for example, a region in which the sensor37cannot be positioned may exist at an end section of the linear scale36.

For example, the length of the movement region SA coincides with the length of distance of movement of the carriage27from the home position P1to the return position P2. In this case, the movement region SA corresponds to a region having the home position P1and the return position P2as end sections in a region in which the carriage27moves.

The length of the movement region SA may be longer than the length of the distance of movement of the carriage27from the home position P1to the return position P2. For example, in a case where the carriage27can move outside the region between the home position P1and the return position P2, then the length of the movement region SA is longer than the length of the distance that the carriage27moves from the home position P1to the return position P2.

The movement region SA includes one first region S1and one or more second regions S2. That is, the linear scale36has a first region S1and a second region S2. The first region S1is a region where the slits38are arranged in the linear scale36. The second region S2is a region where the slits38are not positioned in the linear scale36. The movement region SA includes, for example, one first region S1and two second regions S2.

The first region S1and the second regions S2are adjacent to each other. The two second regions S2are located one on either side of the first region S1. Specifically, the two second regions S2are located upstream and downstream of the first region S1with respect to the first direction A1. When there is one second region S2, then the second region S2may be located to one side of the first region S1.

Since a portion of the movement region SA is the first region S1, the length of the first region S1is shorter compared to a case in which the entire movement region SA were the first region S1. Therefore, for example, compared with the case where the slits38are arranged over the entire length of the linear scale36, the possibility that the positional accuracy of the slits38will be degraded is reduced.

The sensor37is mounted on the carriage27. Therefore, the sensor37moves in one direction together with the carriage27. For example, the sensor37moves in the first direction A1, or in the opposite direction thereof, together with the carriage27.

The sensor37moves along the linear scale36. The sensor37moves over the linear scale36. The position of the carriage27is detected by moving the sensor37over the linear scale36. The sensor37moves in the movement region SA. In other words, the sensor37moves between the first region S1and the second regions S2.

The sensor37is displaced to a plurality of positions by moving along the linear scale36. The sensor37is displaced between a first position Q1and a second position Q2by moving along the linear scale36. In the linear scale36, a first region S1and a second region S2are located between the first position Q1and the second position Q2. By movement of the carriage27, the sensor37moves on the linear scale36between the first position Q1and the second position Q2. The sensor37is displaced to a third position Q3, in addition to the first position Q1and the second position Q2, by moving along the linear scale36. The first position Q1, the third position Q3, and the second position Q2are arranged in this order in the first direction A1, for example.

The first position Q1is a position on the linear scale36where the sensor37is located when the carriage27is located at the home position P1. That is, the first position Q1is a position corresponding to the home position P1. For example, the first position Q1is located at an end section of the movement region SA. For example, the first position Q1is located in the second region S2. The first position Q1may be located in the first region S1.

The second position Q2is a position on the linear scale36where the sensor37is located when the carriage27is located at the return position P2. That is, the second position Q2corresponds to the return position P2. The second position Q2is located, for example, at an end of the movement region SA. For example, the second position Q2is located in the second region S2. For example, the second position Q2is located in a second region S2that is different from the second region S2in which the first position Q1is located. The second position Q2may be located in the first region S1.

The third position Q3is a position on the linear scale36where the sensor37is located when the carriage27is located at the reset position P3. That is, the third position Q3corresponds to the reset position P3. The third position Q3is located in the first region S1. When there are a plurality of reset positions P3, there are also a plurality of third positions Q3.

The sensor37may be displaced on the linear scale36, for example, to a position corresponding to the flushing position. The sensor37may be displaced on the linear scale36, for example, to a position corresponding to a maintenance position.

When the sensor37moves in the first region S1, the control section33can control the ejection timing of liquid by the head28. When the sensor37moves in the second region S2, the control section33cannot control the ejection timing of liquid by the head28. Therefore, the sensor37needs to be positioned in the first region S1while the head28ejects liquid.

The sensor37is located in the first region S1when the head28faces the print region19. That is, when the head28faces the print region19, the first region S1is positioned on the linear scale36so that the sensor37is positioned in the first region S1. When the head28faces the print region19, the sensor37is positioned in the first region S1, and thus it is possible for the control section33to control the ejection timing of liquid by the head28with respect to the print region19.

In order for the sensor37to be positioned in the first region S1when the head28faces the print region19, the length of first region S1needs to be as long as or longer than the length of the print region19. If the length of the first region S1is shorter than length of the print region19, then during the process of the carriage27moving along the guide25, the sensor37will move to outside the first region S1even though the head28faces the print region19.

In order to position the sensor37in the first region S1when the head28faces the print region19, it is desirable that length of the first region S1be as long as or longer than the sum of the lengths of the print region19and the head28. This is because the head28will continue to face the print region19while the head28passes over the print region19. Thus, the head28passes over the print region19by moving a distance which is the sum of the length of the print region19and the length of the head28.

The period during which the head28passes over the print region19is, for example, a period from a state in which one end section of the head28and one end section of the support section17overlap each other to a state in which the other end section of the head28and the other end section of the support section17overlap each other. During this period, the head28continues to face the print region19. For example, the head28faces the print region19during a period from a state in which the second head end section28B and the first support end section17A overlap each other to a state in which the first head end section28A and the second support end section17B overlap each other. Therefore, the first region S1is positioned on the linear scale36so as to correspond to a region from the position of the carriage27where the second head end section28B and the first support end section17A overlap each other to the position of the carriage27where the first head end section28A and the second support end section17B overlap each other.

The length of first region S1is longer than or equal to the length of the print region19with respect to one direction. Specifically, the length of the first region S1in one direction is as long as or longer than the sum of the lengths of the print region19and the head28in the one direction. The length of the first region S1in the first direction A1is, for example, a first region length LA. The length of the print region19in the first direction A1is, for example, a print region length LB. The length of the head28in the first direction A1is, for example, a head length LC. Therefore, the first region length LA is greater than or equal to the print region length LB. Specifically, the first region length LA is greater than or equal to the sum of the print region length LB and the head length LC. Accordingly, the sensor37can be positioned in the first region S1while the head28faces the print region19. When the plurality of heads28are mounted on the carriage27, the head length LC is a length of a region occupied by the plurality of heads28in the carriage27.

The print region length LB corresponds to, for example, the distance from the first support end section17A to the second support end section17B in one direction. The head length LC corresponds to, for example, the distance from the first head end section28A to the second head end section28B in one direction.

The head28ejects liquid not only to the print region19but also to the flushing receiver29. Therefore, the sensor37needs to be positioned in the first region S1even when the head28faces the flushing receiver29.

The sensor37is located in the first region S1when the head28faces the flushing receiver29. That is, the first region S1is positioned on the linear scale36so that the sensor37is positioned in the first region S1when the head28faces the flushing receiver29. By the sensor37being positioned in the first region S1when the head28faces the flushing receiver29, the control section33can control the ejection timing of liquid by the head28with respect to the flushing receiver29.

In order for the sensor37to be positioned in the first region S1when the head28faces the flushing receiver29, the first region S1needs to be positioned on the linear scale36so as to correspond to the position of the carriage27where the head28faces the flushing receiver29. Therefore, the sensor37needs to be positioned in the first region S1while the head28passes over the flushing receiver29and the print region19. Therefore, in order for the sensor37to be positioned in the first region S1when the head28faces the flushing receiver29, the length of the first region S1needs to be equal to or longer than the length of a region having the flushing receiver29and the support section17as end sections.

The period during which the head28passes over the flushing receiver29and over the print region19is a period from a state in which one end section of the head28overlaps with an end section of the flushing receiver29to a state in which the other end section of the head28overlaps with the end section of the support section17. The period during which the head28passes over the flushing receiver29and over the print region19is, for example, a period from a state in which the second head end section28B and the first receiving end section29A overlap each other to a state in which the first head end section28A and the second supporting end section17B overlap each other. Therefore, the first region S1is positioned on the linear scale36so as to correspond to a region from the position of the carriage27where the second head end section28B and the first receiving end section29A overlap each other to the position of the carriage27where the first head end section28A and the second supporting end section17B overlap each other.

In the one direction, the length of the first region S1is longer than or equal to the length of a region having the flushing receiver29and the support section17as ends. The length of the region having the flushing receiver29and the support section17as end sections is, for example, a region length LD. The lengths of the region having the flushing receiver29and the support section17as end sections corresponds, for example, to the distance from the first receiving end section29A to the second support end section17B. The first region length LA is greater than or equal to the region length LD.

When the sensor37moves in the first region S1, the output of the linear encoder35changes by the sensor37reading the slits38. The linear encoder35, for example, outputs a pulse signal by the sensor37reading the slits38. For example, the control section33controls the ejection timing of liquid by the head28based on the pulse signal. On the other hand, when the sensor37moves in the second region S2, the output of the linear encoder35does not change because the sensor37cannot read the slits38.

The control section33controls the ejection timing of liquid by the head28with reference to the reset position P3. When the sensor37moves to the outside of the first region S1, since the sensor37cannot read the slits38, it is difficult for the control section33to accurately control the ejection timing of liquid by the head28with reference to the reset position P3. That is, when the sensor37passes through the second region S2, it is difficult for the control section33to accurately control the ejection timing of liquid by the head28based on the output of the linear encoder35. For example, when the sensor37moves in the order of the first region S1, the second region S2, and the first region S1, it is difficult for the control section33to accurately control the ejection timing of liquid by the head28based on the output of the linear encoder35. Therefore, when the sensor37moves from the second region S2to the first region S1, it is necessary to reset the output of the linear encoder35.

When the sensor37moves from the second region S2to the first region S1, the control section33resets the output of the linear encoder35before the head28ejects liquid to the print region19. The control section33resets the output of the linear encoder35when the carriage27reaches the reset position P3after the sensor37moves from the second region S2to the first region S1. The control section33resets the output of the linear encoder35when the sensor37has moved from the second region S2to the first region S1and the sensor37reaches the third position Q3. After the output of the linear encoder35is reset at the reset position P3, liquid is ejected from the head28in a state where the sensor37is positioned in the first region S1.

With respect to resetting the output of the linear encoder35and the process in which the sensor37moves from the second region S2to the first region S1, it is desirable that the sensor37be able to pass through the reset position P3before the head28faces the print region19. In this case, printing is smoothly performed. For example, while the carriage27reciprocates during printing, if the output of the linear encoder35is reset immediately before the head28faces the print region19, printing is smoothly executed.

A case of this example in which both the first position Q1and the second position Q2are located in the second region S2will be considered. When unidirectional printing is performed in the forward path, the reset position P3may be located between the home position P1and the print region19in one direction. In this case, the sensor37moves from the second region S2to the first region S1as the carriage27that was located at the home position P1moves in the forward path. After the sensor37moves to the first region S1, the output of the linear encoder35is reset by the carriage27reaching the reset position P3. Thereafter, the carriage27continues to move in the forward path, whereby the head28ejects liquid to the print region19.

When unidirectional printing is performed in the return path, the reset position P3may be positioned between the print region19and the return position P2in one direction. In this case, the sensor37moves from the second region S2to the first region S1by the carriage27located at the return position P2moving in the return path. After the sensor37enters the first region S1, the output of the linear encoder35is reset by the carriage27reaching the reset position P3. Thereafter, the carriage27continues to move in the return path, whereby the head28ejects liquid to the print region19.

In the case of bi-directional printing, the reset position P3may be located, with respect to one direction, between the home position P1and the print region19and between the print region19and the return position P2. In this case, the sensor37moves from the second region S2to the first region S1as the carriage27that was located at the home position P1moves in the forward path. After the sensor37enters the first region S1, the output of the linear encoder35is reset by the carriage27reaching the reset position P3. Thereafter, the carriage27continues to move in the forward path, whereby the head28ejects liquid to the print region19. Also, when the carriage27located at the return position P2moves in the return path, the sensor37moves from the second region S2to the first region S1. After the sensor37enters the first region S1, the output of the linear encoder35is reset by the carriage27reaching the reset position P3. Thereafter, the carriage27continues to move in the return path, whereby the head28ejects liquid to the print region19.

As described above, the control method of the printing device11includes controlling the position of the carriage27based on the output of the rotary encoder32. The control method of the printing device11includes controlling the ejection timing of liquid by the head28based on the output of the linear encoder35. The control method of the printing device11includes resetting the output of the linear encoder35before the head28ejects liquid to the print region19when the sensor37moves from the second region S2to the first region S1.

Actions and Effects of Printing Device

Next, actions and effects of the above-described embodiment will be described. (1) When the head28faces the print region19, the sensor37is positioned in the first region S1. The length of the first region S1is longer than or equal to the length of the print region19in the one direction.

When the head28faces the print region19, for example, when the head28prints on the medium99, the sensor37is located in the first region S1. Since the length of the first region S1is longer than or equal to the length of the print region19, the sensor37continues to be positioned in the first region S1while the head28faces the print region19. Accordingly, the control section33can control the ejection timing of liquid by the head28with respect to the print region19.

According to the above configuration, the slits38are arranged in a partial region of the linear scale36. In this case, the length of the first region S1is shorter than in the case where the slits38are arranged over the entire length of the linear scale36. Therefore, it is possible to reduce the possibility that the positional accuracy of the slits38is lowered. Therefore, the possibility that the print quality deteriorates is reduced.

(2) When the sensor37moves from the second region S2to the first region S1, the control section33resets the output of the linear encoder35before the head28ejects liquid to the print region19.

When the sensor37moves from the first region S1to the second region S2, the sensor37cannot read the slits38. Therefore, in a case where the sensor37moves from the second region S2to the first region S1, it is difficult for the control section33to accurately control the ejection timing of liquid by the head28based on the output of the linear encoder35. Therefore, when the sensor37moves from the second region S2to the first region S1, it is necessary to reset the output of the linear encoder35. According to the configuration described above, the control section33can control the ejection timing of liquid by the head28based on the output of the linear encoder35that was reset.

(3) When the head28faces the flushing receiver29, the sensor37is positioned in the first region S1. With respect to one direction, the length of the first region S1is longer than or equal to the length of a region having the flushing receiver29and the support section17as end sections.

According to the configuration described above, the control section33can control the ejection timing of liquid by the head28with respect to the flushing receiver29. By this, the control section33can cause the flushing receiver29to receive the liquid ejected from the head28by flushing.

Modifications of Printing Device

The above-described embodiment can be modified as follows. The present embodiment and the following modifications can be implemented in combination with each other within a range where there is no technical contradiction.

First Modification

A first modification of the printing device11will be described. In the first modification, the position of the flushing receiver29is different from that in the above-described embodiment. The first modification will be mainly described with respect to points different from the above-described embodiment.

As shown inFIG.3, the flushing receiver29may be located downstream of the support section17in the first direction A1. The flushing receiver29faces the head28when the carriage27is located at the flushing position.

The sensor37is located in the first region S1when the head28faces the flushing receiver29. That is, the first region S1is positioned on the linear scale36so that the sensor37is positioned in the first region S1when the head28faces the flushing receiver29.

In order for the sensor37to be positioned in the first region S1when the head28faces the flushing receiver29, the first region S1needs to be positioned on the linear scale36so as to correspond to the position of the carriage27where the head28faces the flushing receiver29. Therefore, the sensor37needs to be positioned in the first region S1while the head28passes over the flushing receiver29and the print region19. Therefore, in order for the sensor37to be positioned in the first region S1when the head28faces the flushing receiver29, the length of the first region S1needs to be equal to or longer than the length of a region having the flushing receiver29and the support section17as end sections.

The period during which the head28passes over the flushing receiver29and over the print region19is a period from a state in which one end section of the head28overlaps with an end section of the flushing receiver29to a state in which the other end section of the head28overlaps with the end section of the support section17. In the first modification, the period during which the head28passes over the flushing receiver29and over the print region19is a period from a state in which the second head end section28B and the first support end section17A overlap each other to a state in which the first head end section28A and the second receiving end section29B overlap each other. Therefore, in the first modification, the first region S1is positioned on the linear scale36so as to correspond to a region from the position of the carriage27where the second head end section28B and the first support end section17A overlap each other to the position of the carriage27where the first head end section28A and the second receiving end section29B overlap each other.

In the one direction, the length of the first region S1is longer than or equal to the length of a region having the flushing receiver29and the support section17as ends. The length of the region having the flushing receiver29and the support section17as end sections is, for example, a region length LD. In the first modification, the length of the region including the flushing receiver29and the support section17corresponds to the distance from the first support end section17A to the second receiving end section29B. The first region length LA is greater than or equal to the region length LD. According to the first modification, the same effects as those of the above embodiment can be obtained.

Second Modification

Next, a second modification of the printing device11will be described. The second modification is different from the above-described embodiment in that the second region S2is located on only one side of the first region S1. The second modification will be mainly described with respect to points different from the above-described embodiment.

As shown inFIGS.4and5, one second region S2may be provided in the movement region SA. The second region S2is located on one side of the first region S1. In the second modification, the second region S2is located upstream of the first region S1in the first direction A1. Also in the second modification, since a portion of the movement region SA is the first region S1, the length of the first region S1is shorter than a case in which the entire movement region SA is the first region S1. Therefore, for example, compared with the case where the slits38are arranged over the entire length of the linear scale36, the possibility that the positional accuracy of the slits38will be degraded is reduced.

In the second modification, the first position Q1is located in the second region S2. On the other hand, the second position Q2is located in the first region S1. In this case, when the carriage27is positioned at the return position P2, the sensor37is not positioned at the second region S2.

As shown inFIG.5, with respect to one direction, the movement distance of the carriage27from the home position P1to the support section17is longer than the movement distance of the carriage27from the return position P2to the support section17. The movement distance of the carriage27from the home position P1to the support section17is, for example, a first distance R1. The movement distance of the carriage27from the return position P2to the support section17is, for example, a second distance R2. In the second modification, the first distance R1is longer than the second distance R2.

The movement distance of the carriage27from the home position P1to the support section17corresponds to, for example, the distance from the second carriage end section27B of the carriage27positioned at the home position P1to the first support end section17A. In this case, the movement distance of the carriage27from the return position P2to the support section17corresponds to the distance from the second carriage end section27B of the carriage27located at the return position P2to the second support end section17B.

The movement distance of the carriage27from the home position P1to the support section17may correspond to, for example, the distance from the first carriage end section27A of the carriage27positioned at the home position P1to the first support end section17A. In this case, the movement distance of the carriage27from the return position P2to the support section17corresponds to the distance from the first carriage end section27A of the carriage27located at the return position P2to the second support end section17B.

According to the second modification, the following effects can be obtained in addition to the effects of the above-described embodiment. (4) The second position Q2is located in the first region S1. According to the above configuration, when the carriage27is positioned at the return position P2, the sensor37is not positioned at the second region S2. Therefore, for example, when the carriage27moves from the return position P2to the home position P1, it is not necessary to reset the output of the linear encoder35. Therefore, it is possible to reduce the frequency of resetting the output of the linear encoder35compared to a case in which the sensor37moves to the second region S2when the carriage27moves to the return position P2.

(5) With respect to one direction, the movement distance of the carriage27from the home position P1to the support section17is longer than the movement distance of the carriage27from the return position P2to the support section17.

According to the above-described configuration, the length of the first region S1is shorter than in a case where the movement distance of the carriage27from the home position P1to the support section17is shorter than the movement distance of the carriage27from the return position P2to the support section17. Therefore, it is possible to reduce the possibility that positional accuracy of the slits38is lowered.

Third Modification

Next, a third modification of the printing device11will be described. In the third modification, the position of the second region S2is different from that in the second modification. Regarding the third modification, points different from the second modification will be mainly described.

As shown inFIGS.6and7, a single second region S2may be provided in the movement region SA. The second region S2is located on one side of the first region S1. In the third modification, the second region S2is located downstream of the first region S1in the first direction A1. Also in the third modification, since a portion of the movement region SA is the first region S1, the length of the first region S1is shorter than the case where the entire movement region SA is the first region S1. Therefore, for example, compared with the case where the slits38are arranged over the entire length of the linear scale36, the possibility that the positional accuracy of the slits38will be degraded is reduced.

In the third modification, the first position Q1is located in the first region S1. On the other hand, the second position Q2is located in the second region S2. In this case, when the carriage27is positioned at the home position P1, the sensor37is not positioned at the second region S2.

As shown inFIG.7, with respect to the one direction, the movement distance of the carriage27from the home position P1to the support section17is shorter than the movement distance of the carriage27from the return position P2to the support section17. The movement distance of the carriage27from the home position P1to the support section17is, for example, a first distance R1. The movement distance of the carriage27from the return position P2to the support section17is, for example, a second distance R2. In the third modification, the first distance R1is shorter than the second distance R2.

According to the third modification, the following effects can be obtained in addition to the effects of the above-described embodiment. (6) The first position Q1is located in the first region S1. According to the above configuration, when the carriage27is located at the home position P1, the sensor37is not located in the second region S2. Therefore, for example, when the carriage27moves from the home position P1to the return position P2, it is not necessary to reset the output of the linear encoder35. Therefore, it is possible to reduce the frequency of resetting the output of the linear encoder35as compared with a case where the sensor37moves to the second region S2when the carriage27moves to the home position P1.

(7) With respect to one direction, the movement distance of the carriage27from the home position P1to the support section17is shorter than the movement length of the carriage27from the return position P2to the support section17.

According to the above-described configuration, the length of the first region S1is shorter than in a case where the movement distance of the carriage27from the home position P1to the support section17is longer than the movement distance of the carriage27from the return position P2to the support section17. Therefore, it is possible to reduce the possibility that positional accuracy of the slits38is lowered.

Other Modifications

The control section33may detect that the carriage27is positioned at the reset position P3by, for example, a switch that comes into contact with the carriage27, and is not limited to using the output of the rotary encoder32. The control section33may detect the home position P1and the return position P2using a similar technique.

The liquid ejected by the head28is not limited to ink, and may be, for example, a liquid material in which particles of a functional material are dispersed in or mixed with a liquid. For example, the head28may eject a liquid material containing a material, in a dispersed or dissolved form, such as an electrode material or a pixel material used for manufacturing liquid crystal displays, electroluminescence displays, or surface light emission displays.

Technical Ideas

Hereinafter, technical ideas grasped from the above-described embodiment and modifications, and actions and effects thereof, will be described.

(A) A printing device includes a support section configured to support a medium; a head configured to eject liquid onto a print region of the medium, the print region being a region of the medium that is supported by the support section; a carriage on which the head is mounted; a guide that supports the carriage and that extends in one direction; a motor configured to move the carriage along the guide between a home position and a return position; a rotary encoder for detecting a rotation angle of the motor; a linear encoder configured to detect a position of the carriage; and a control section, wherein the control section controls a position of the carriage based on output of the rotary encoder and controls ejection timing of liquid by the head based on output of the linear encoder, the support section faces the head by the carriage moving between the home position and the return position, the linear encoder includes a linear scale that extends in the one direction and that has a plurality of slits arranged in the one direction and a sensor that is attached to the carriage and that is configured to detect the slits, by movement of the carriage, the sensor moves over the linear scale between a first position and a second position, the first position is a position on the linear scale where the sensor is located when the carriage is located at the home position, the second position is a position on the linear scale where the sensor is located when the carriage is located at the return position, the linear scale includes, between the first position and the second position, a first region in which the plurality of slits are located and a second region in which the plurality of slits are not located, the sensor is located in the first region when the head faces the print region, and a length of the first region in the one direction is greater than or equal to a length of the print region in the one direction.

When the head faces the print region, for example when the head prints on the medium, the sensor is located in the first region. Since the length of the first region is greater than or equal to the length of the printing region, the sensor continues to be positioned in the first region while the head faces the printing region. Accordingly, the control section can control the ejection timing of liquid by the head with respect to the printing region.

According to the above configuration, the slits are arranged in a partial region of the linear scale. In this case, the length of the first region is shorter than in the case where the slits are arranged over the entire length of the linear scale. Therefore, it is possible to reduce the possibility that the positional accuracy of the slits is lowered. Therefore, the possibility that the print quality deteriorates is reduced.

(B) In the above-described printing device, when the sensor moves from the second region to the first region, the control section may reset output of the linear encoder before the head ejects liquid to the printing region.

When the sensor moves from the first region to the second region, the sensor cannot read the slits. Therefore, in a case where the sensor moves from the second region to the first region, it is difficult for the control section to accurately control the ejection timing of liquid by the head based on the output of the linear encoder. Therefore, when the sensor moves from the second region to the first region, it is necessary to reset the output of the linear encoder. According to the configuration described above, the control section can control the ejection timing of liquid by the head based on the output of the linear encoder that was reset.

(C) The above-described printing device may be such as to further include a flushing receiver configured to receive liquid ejected from the head by flushing, wherein the flushing receiver is arranged with the support section in the one direction, and the sensor is positioned in the first region when the head faces the flushing receiver and the length in the one direction of the first region is greater than or equal to a length in the one direction of a region having the flushing receiver and the support section as end sections.

According to the configuration described above, the control section can control the ejection timing of liquid by the head with respect to the flushing receiver. By this, the control section can cause the flushing receiver to receive the liquid ejected from the head by flushing.

(D) In the above-described printing device, the second position may be located in the first region. According to the above configuration, when the carriage is positioned at the return position, the sensor is not positioned in the second region. Therefore, for example, when the carriage moves from the return position to the home position, it is not necessary to reset the output of the linear encoder. Therefore, it is possible to reduce the frequency of resetting the output of the linear encoder as compared with a case where the sensor moves to the second region by moving the carriage to the return position.
(E) In the above-described printing device,in the one direction, a movement distance of the carriage from the home position to the support section may be longer than a movement distance of the carriage from the return position to the support section.

According to the above configuration, the length of the first region is shorter than in a case where the movement distance of the carriage from the home position to the support section is shorter than the movement distance of the carriage from the return position to the support section. Therefore, it is possible to reduce the possibility that the positional accuracy of the slits is lowered.

(F) The first position may be located in the first region. According to the above configuration, when the carriage is located at the home position, the sensor is not located in the second region. Therefore, for example, when the carriage moves from the home position to the return position, it is not necessary to reset the output of the linear encoder. Therefore, it is possible to reduce the frequency of resetting the output of the linear encoder as compared with a case where the sensor moves to the second region when the carriage moves to the home position.
(G) In the above-described printing device, in the one direction, a movement distance of the carriage from the home position to the support section may be shorter than a movement distance of the carriage from the return position to the support section.

According to the above configuration, the length of the first region is shorter than in a case where the movement distance of the carriage from the home position to the support section is longer than the movement distance of the carriage from the return position to the support section. Therefore, it is possible to reduce the possibility that the positional accuracy of the slits is lowered.

(H) A printing device control method for a printing device including a support section configured to support a medium, a head configured to eject liquid onto a print region of the medium, the print region being a region of the medium that is supported by the support section, a carriage on which the head is mounted, a guide that supports the carriage and that extends in one direction, a motor configured to move the carriage along the guide between a home position and a return position, a rotary encoder for detecting a rotation angle of the motor, and a linear encoder configured to detect a position of the carriage, the support section faces the head by the carriage moving between the home position and the return position, the linear encoder includes a linear scale that extends in the one direction and that has a plurality of slits arranged in the one direction and a sensor that is attached to the carriage and that is configured to detect the slits, by movement of the carriage, the sensor moves over the linear scale between a first position and a second position, the first position is a position on the linear scale where the sensor is located when the carriage is located at the home position, the second position is a position on the linear scale where the sensor is located when the carriage is located at the return position, the linear scale includes, between the first position and the second position, a first region in which the plurality of slits are located and a second region in which the plurality of slits are not located, the sensor is located in the first region when the head ejects liquid at the print region, and a length of the first region in the one direction is longer than a length of the print region in the one direction, the printing device control method comprising: controlling position of the carriage based on output of the rotary encoder; controlling ejection timing of the liquid by the head based on output of the linear encoder; and when the sensor moves from the second region to the first region, output of the linear encoder is reset before the head ejects liquid to the printing region.

According to the method described above, similar effects as those of the printing device described above can be obtained.