Roll paper printer and control method for roll paper printer

Abstract

To provide a roll paper printer and a control method for a roll paper printer that prevent complication of the mechanism for detecting the near end when the installation posture is different.SOLUTION: A roll paper printer can be installed in a first installation position and a second installation position that is different from the first installation position and includes a storage case that can store roll paper and a sensor that can detect the distance to the outer periphery of the roll paper by emitting detection light or transmitting a detection wave from the storage case. The sensor can emit the detection light or transmit the detection wave to the outer periphery of either the roll paper stored in the storage case in the first installation position or the roll paper stored in the storage case in the second installation position.SELECTED DRAWING: Figure 6

Description

[Technical field]

[0001] The present invention relates to a roll paper printer and a method for controlling a roll paper printer. [Background technology]

[0002] As disclosed in Patent Documents 1 and 2, printers are known that can detect when the diameter of the roll paper is equal to or smaller than a predetermined value, that is, when the roll paper is near the end, even when the printer is in a different installation position. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 9-295436 [Patent Document 2] JP 2010-234560 A Summary of the Invention [Problem to be solved by the invention]

[0004] The printer in Patent Document 1 has a configuration in which the mechanism for detecting the near end moves according to the installation posture, while the printer in Patent Document 2 has a configuration in which multiple mechanisms for detecting the near end are provided, both of which have complex configurations with a large number of parts, which may result in expensive and large printers. Furthermore, the printer in Patent Document 1 requires the user to move the mechanism. [Means for solving the problem]

[0005] A roll paper printer that solves the above problems is installable in a first installation position and a second installation position different from the first installation position, and comprises a storage case capable of storing roll paper with paper wound around it, and a sensor that can detect the distance to the outer periphery of the roll paper by emitting detection light or emitting detection waves from the storage case, and the sensor is capable of emitting the detection light or emitting the detection wave to the outer periphery of either the roll paper stored in the storage case in the first installation position, or the roll paper stored in the storage case in the second installation position.

[0006] A control method for a roll paper printer that solves the above-mentioned problems is a control method for a roll paper printer that has a storage case that can store roll paper with paper wound around it in either a first installation position or a second installation position that is different from the first installation position, a sensor that can irradiate detection light or emit detection waves to the outer circumference of either the roll paper stored in the storage case in the first installation position or the roll paper stored in the storage case in the second installation position and can detect the distance between the roll paper, and a roller that transports the paper, and whether the storage case is in the first installation position or the second installation position, the paper is transported by the roller, and when the distance detected by the sensor becomes equal to or greater than a predetermined distance, it is determined that the roll paper has transitioned from a first diameter to a second diameter that is smaller than the first diameter. [Brief description of the drawings]

[0007] [Figure 1] FIG. [Diagram 2] A cross-sectional view of the roll paper printer when the sensor detects the distance of a first diameter roll paper stored in a storage case in a first installation position. [Diagram 3] A cross-sectional view of the roll paper printer when the sensor detects the distance of the second diameter roll paper stored in the storage case in the first installation position. [Figure 4]A cross-sectional view of the roll paper printer when the sensor detects the distance of a first diameter roll paper stored in a storage case in the second installation position. [Diagram 5] A cross-sectional view of the roll paper printer when the sensor detects the distance of the second diameter roll paper stored in the storage case in the second installation position. [Figure 6] 11 is a cross-sectional view of the roll paper printer showing a comparison between when the printer case is in the first installation position and when the sensor is detecting the distance of the second diameter roll paper. FIG. [Figure 7] FIG. 7 is a cross-sectional view of the roll paper printer showing a comparison between when the storage case is in the first installation position and when the sensor, located in a different position from that shown in FIGS. 2 to 6, detects the distance to the second diameter roll paper. [Figure 8] 6 is a flowchart showing a control method for a roll paper printer that uses a sensor to determine the diameter of the roll paper. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] 1. Configuration of a roll paper printer The configuration of a roll paper printer 1 according to an embodiment is described below with reference to Figures 1 to 7. The directions in the figures are described using a three-dimensional coordinate system. For ease of explanation, the positive direction of the Z axis will be referred to as the upward direction, upward, or simply upward; the negative direction will be referred to as the downward direction, downward, or simply downward; the positive direction of the X axis will be referred to as the rightward direction, rightward, or simply right; the negative direction will be referred to as the leftward direction, leftward, or simply left; the positive direction of the Y axis will be referred to as the forward direction, forward, or simply forward; and the negative direction will be referred to as the rearward direction, rearward, or simply rear.

[0009] The roll paper printer 1 according to this embodiment is used, for example, in a POS (Point Of Sale) system that includes a computer. POS systems are used in retail businesses such as shopping centers, department stores, convenience stores, and in-car sales, as well as food and beverage businesses such as restaurants, coffee shops, and izakayas. The roll paper printer 1 used in a POS system prints receipts, coupons, tickets, and other documents depending on the product or service.

[0010] The roll paper printer 1 can be installed so that the storage case 12 is in a first installation position A or a second installation position B that is different from the first installation position A. 1 to 3 and 6 to 7 show the storage case 12 in the first installation position A. In the first installation position A, the roll paper printer 1 is in an installation position in which the cover 10 can be opened forward, which is one side of the exterior case 11. In first installation position A, the roll paper printer 1 is in an installation position in which the output outlet 13 (described below) is located at the front, and is also called the front-loading installation position or the portrait installation position.

[0011] 4 and 5 show the storage case 12 in the second installation position B. In the second installation position B, the roll paper printer 1 is in an installation position in which the cover 10 can be opened above the exterior case 11. In second installation position B, the roll paper printer 1 is in an installation position in which the ejection port 13 is located at the top, and is also called the top-loading installation position or horizontal installation position.

[0012] 1 is a perspective view of the roll paper printer 1 with the cover 10 open forward and no roll paper (described below) stored in the storage case 12. Note that in the following, roll papers RA1, RA2, RB1, and RB2 (described below) will be collectively referred to as roll paper R. The size of roll paper R is not specified, and the installation position of the storage case 12 in which it is stored is not specified. The width of the storage case 12 in the left-right direction is width W, and it can store roll paper R up to width W. Width W is, for example, 80 mm.

[0013] The cover 10 can open and close the storage case 12. When the user opens the cover 10 toward the front, the user can access the storage case 12 and store the roll paper R in the storage case 12 from the front. 2 to 7 show cross-sectional views of the roll paper printer 1 with the cover 10 closed.

[0014] 2, roll paper R that is stored in storage case 12 in first installation position A and has a first diameter D1 that is larger than roll paper RA2, which will be described later, will be referred to as roll paper RA1. The configuration of the roll paper printer 1 will be described in detail with reference to FIG. 2. The paper P is, for example, a long piece of thermal paper. The paper P is wound around a core (not shown) to become rolled paper RA1. The outer diameter of the core is, for example, 18 mm. The first diameter D1, which is the outer diameter of the rolled paper RA1 before use, is, for example, 83 mm. In the following, the outer diameter of the rolled paper R etc. will also be simply referred to as the diameter.

[0015] By inserting a partition plate (not shown) into the storage case 12, the storage case 12 can accommodate roll paper R with a paper width of, for example, 58 mm to 80 mm. 3 to 7, the path along which the paper P is transported is the same as in FIG. 2, and therefore is omitted for convenience of explanation.

[0016] The roll paper printer 1 has a control unit 15. The control unit 15 includes a CPU (Central Processing Unit) that provides overall control of each part of the roll paper printer 1, a UART (Universal Asynchronous Receiver Transmitter) that manages input and output, and logic circuits such as an FPGA (Field Programmable Gate Array) and a PLD (Programmable Logic Device). The CPU is also called a processor. The control unit 15 is configured to include memories such as a flash ROM (Read Only Memory), which is a rewritable non-volatile memory, an HDD (Hard Disk Drive), and a RAM (Random Access Memory), which is a volatile memory. The CPU of the control unit 15 reads and executes programs such as firmware stored in the memory.

[0017] In addition to the cover 10, exterior case 11, storage case 12, and control unit 15 described above, the roll paper printer 1 also includes a head 2, roller 3, paper guide 4, protrusions 5, sensor 6, and cutter 14. The head 2, the protrusion 5, the sensor 6, the storage case 12, and the fixed blade 14b of the cutter 14 are mounted in the exterior case 11. Meanwhile, the roller 3, the paper guide 4, the support roller 8, the cover guide 9, and the movable blade 14a of the cutter 14 are mounted in the cover 10.

[0018] The cover 10 is attached by a cover hinge 10a to the front side of the outer case 11. The cover 10 is rotatable about the cover hinge 10a. When the cover 10 is closed, a rectangular ejection outlet 13 is formed at the boundary between the cover 10 and the exterior case 11. The ejection outlet 13 is formed at the front of the roll paper printer 1, and paper P printed by the head 2 is ejected from the front.

[0019] Furthermore, when the cover 10 is closed, the roller 3 mounted on the cover 10 is positioned opposite the head 2 mounted on the exterior case 11. The roller 3 facing the head 2 is also called a platen roller. Furthermore, at this time, the movable blade 14a of the cutter 14 mounted on the cover 10 is positioned opposite the fixed blade 14b mounted on the exterior case 11. The protrusion 5 is also positioned opposite the paper guide 4.

[0020] The roller 3 is rotated counterclockwise by a transport motor (not shown) to transport the paper P in the transport direction F. At this time, as the roller 3 pulls out the paper P from the roll paper RA1, the roll paper RA1 also rotates counterclockwise. Arranged from upstream to downstream in the conveying direction F are the storage case 12, the paper guide 4 and the protrusions 5, the roller 3 and the head 2, the cutter 14, and the discharge port 13 in this order.

[0021] The protrusion 5 and the paper guide 4 are configured to be able to guide the paper P upstream of the roller 3 in the transport direction F. The protrusion 5 is located opposite the recess of the paper guide 4. The paper P is bent between the protrusion 5 and the recessed portion of the paper guide 4. The protrusion 5 is capable of coming into contact with the paper P, and is configured to be movable toward and away from the paper guide 4 by an elastic member (not shown) configured of a spring, rubber, or the like.

[0022] Since the paper P is wound around the core, it has a curl due to its tendency to roll. The protrusions 5 come into contact with the curled paper P and act to straighten the curl. Specifically, the protrusions 5 come into contact with the paper P and bend it to straighten the curl. When the paper P is transported by the rollers 3, it is squeezed by the protrusions 5, and the curl is straightened.

[0023] At this time, the tension of the paper P may also fluctuate, but the protrusion 5 can move forward and backward relative to the paper guide 4 and buffer the fluctuation in the tension of the paper P. As a result, the paper P can be transported stably. As described below, when paper P is pulled out from the roll paper RA1, the roll paper RA1 rotates counterclockwise. At this time, the protrusions 5 ensure stable transport of the paper P, so the roll paper RA1 can also be maintained in a stable position.

[0024] The head 2 is, for example, a line-type thermal head with multiple heating elements arranged in the left-right direction. The multiple heating elements of the head 2 are selected to generate heat based on print data sent from a computer in the POS system, and can print an image on the paper P, which is thermal paper. The roller 3 and head 2 are positioned opposite each other, sandwiching the paper P pulled out from the roll paper RA1. The roller 3 comes into contact with the transport surface of the paper P to enable transport, and the head 2 comes into contact with the printing surface of the paper P to enable printing.

[0025] The roller 3, which is positioned opposite the head 2 across the paper P, is also called a platen roller. The roller 3 may be mounted in the exterior case 11, and the head 2 may be mounted in the cover 10. In this case, the printing surface of the paper P will be on the opposite side.

[0026] The movable blade 14a and the fixed blade 14b of the cutter 14 are positioned to face each other with the paper P between them. The movable blade 14a moves toward the fixed blade 14b, and can cut the paper P between them. The cut paper P is discharged from the discharge port 13. Alternatively, the movable blade 14a may be mounted on the exterior case 11, and the fixed blade 14b may be mounted on the cover 10.

[0027] The storage case 12 includes a first storage case 12a, a second storage case 12b, a third storage case 12c, and a fourth storage case 12d, which are arranged from top to bottom in that order toward the cover hinge 10a. The cover guide 9 is mounted on the cover 10 and can abut against the roll paper R. The storage case 12 and the cover guide 9 are configured to be able to guide the roll paper R, the diameter of which changes as the paper P is transported during printing.

[0028] In the case of the roll paper RA1 shown in FIG. 2, the outer periphery CA1 of the roll paper RA1 comes into contact with the third accommodating case 12c and the cover guide 9, and is guided from the front-rear direction. For this reason, the roll paper RA1 can be maintained in a stable position even when the roller 3 pulls out the paper P from the roll paper RA1 and rotates counterclockwise. As described below, the accuracy can be improved when the sensor 6 detects the distance X to the outer periphery CA1 of the roll paper RA1. Incidentally, the roll paper RA1 with the first diameter D1 does not come into contact with the support roller 8 located below the cover guide 9 because the roll paper RA1 has a large diameter.

[0029] The sensor 6 is a so-called distance sensor. The sensor 6 has, for example, a light-emitting element capable of emitting detection light such as an infrared laser, and a light-receiving element capable of receiving the detection light reflected by an object and returning. The sensor 6 may be of a time-of-flight type that measures the time it takes for detection light emitted from a light-emitting element to be reflected by the object and return to a light-receiving element to detect the distance to the object.The sensor 6 may also be of a triangulation type that detects the distance to the object based on the position at which detection light emitted from a light-emitting element is reflected by the object and received on the light-receiving element.

[0030] Furthermore, the sensor 6 may use detection waves such as microwaves and ultrasonic waves, in addition to detection light. In this case, the sensor 6 has a transmitting element that transmits the detection waves and a receiving element that receives the detection waves. Even in the case of using detection waves, the sensor 6 can detect the distance to the target object by a time-of-flight method or the like. In the following, the sensor 6 will be described as using detection light, but the same applies when a detection wave is used. Also, the sensor 7 described below has the same configuration as the sensor 6 described above.

[0031] 2, the sensor 6 is placed on the side of the storage case 12 opposite the side where the roll paper R is stored, so as not to come into contact with the roll paper R. The sensor 6 may also be mounted on the board on which the control unit 15 is mounted. This allows the roll paper printer 1 to be made more compact. An optical axis 6a of the detection light of the sensor 6 is in a front-down direction from the third housing case 12c side toward the fourth housing case 12d or the cover guide 9 side. The third housing case 12c is provided with an opening through which the detection light passes. The opening may be covered with a resin through which the detection light can pass. When the sensor 6 uses a detection wave, the optical axis 6a serves as a propagation path for the detection wave.

[0032] The distance detected by sensor 6 is distance X. The detection light of sensor 6 travels in the direction of optical axis 6a and is irradiated onto the outer circumference CA1 of roll paper RA1. The detection light is reflected off the outer circumference CA1 of roll paper RA1 and returns, allowing sensor 6 to detect distance L1 as distance X. Distance L1 is the distance from sensor 6 to the outer circumference CA1 of roll paper RA1.

[0033] Next, as shown in FIG. 3, the roll paper R with the second diameter D2 accommodated in the accommodation case 12 in the first installation position A is referred to as roll paper RA2. As the paper P is printed and transported from the roll paper RA1 shown in FIG. 2, it becomes roll paper RA2 with a second diameter D2 that is smaller than the first diameter D1. The second diameter D2 is, for example, 24 mm. The second diameter D2 may be within a range of 20 mm or more and 30 mm or less. As the diameter of the roll paper RA1 becomes smaller, it moves forward and downward in the storage case 12. This moving direction is also the direction away from the sensor 6. In the case of roll paper RA2, its outer periphery CA2 comes into contact with the concave fourth housing case 12d and is guided from the front-rear direction. A part of the outer periphery CA2 of roll paper RA2 may come into contact with and be guided by the third housing case 12c.

[0034] The cover guide 9 is also equipped with a rotatable support roller 8 that can come into contact with the outer periphery CA2 of the roll paper RA2. The support roller 8 can move back and forth, and acts to push the roll paper RA2 backwards by a torsion coil spring (not shown). By coming into contact with the support roller 8, the roll paper RA2 becomes lighter and easier to move, and can be stably supported. In this way, the fourth housing case 12d and other components allow the roll paper RA2 to be maintained in a stable position even when the roller 3 pulls out paper P from the roll paper RA2 and rotates counterclockwise. The sensor 6 can accurately detect the distance X to the outer periphery CA2 of the roll paper RA2.

[0035] The detection light of the sensor 6 travels in the direction of the optical axis 6a and is irradiated onto the outer circumference CA2 of the roll paper RA2. The detection light is reflected off the outer circumference CA2 of the roll paper RA2 and returns, allowing the sensor 6 to detect a predetermined distance LA as the distance X. The distance LA is the distance from the sensor 6 to the outer circumference CA2 of the roll paper RA2. The distance LA is, for example, 75 mm. The distance LA may be within a range of 70 mm or more and 80 mm or less. In this way, when the diameter of the roll paper R transitions from the first diameter D1 to the second diameter D2, the sensor 6 can detect the distance LA. Note that when the diameter of the roll paper R transitions from the first diameter D1 to the second diameter D2, the distance X detected by the sensor 6 gradually increases from the distance L1 to the distance LA.

[0036] When the diameter of the roll paper R becomes smaller and the sensor 6 detects the distance LA, the control unit 15 can determine that the diameter of the roll paper R has transitioned from the first diameter D1 to the second diameter D2. In other words, the control unit 15 can determine that the remaining amount of paper P wound around the roll paper R is low, that is, that the roll paper R is near the end. Such a sensor 6 is also called a near-end sensor. On the other hand, when the control unit 15 detects a distance X that is shorter than the distance LA by the sensor 6, it can determine that there is a sufficient amount of paper P remaining on the roll paper R and that the roll paper R is not yet near the end.

[0037] The roll paper printer 1 is equipped with a display device (not shown) that includes an LED or LCD panel. If the sensor 6 determines that the roll is near the end, the control unit 15 can display this information on the display device. The control unit 15 can also send the near-end information to the POS system computer. With this configuration, the roll paper printer 1 does not have a display device, and the near-end information can be displayed on the display of the POS system computer, etc. Furthermore, the control unit 15 may stop printing when it determines that the printer is near the end.

[0038] Even if the control unit 15 determines that the roll paper R is near the end using the sensor 6, it is possible to continue printing as long as there is still paper P remaining on the roll paper R. For example, if the second diameter D2 is 24 mm and the roll paper RA2 is near the end, the remaining amount of paper P on the roll paper RA2 is approximately 3 m. Even after determining that the roll paper RA2 is near the end, the control unit 15 can still print up to a point where the paper P is approximately 3 m long.

[0039] When the user sees the near end indication on the display device, if printing is necessary, such as when customers are lining up to pay, they can continue printing as long as there is within approximately 3 m of paper P. The user can insert new roll paper R into the roll paper printer 1 when receipt printing has finished or when there are no more customers.

[0040] The roll paper printer 1 may also be configured so that a separate paper sensor (not shown) that can detect the presence or absence of paper P is mounted on the paper guide 4 or protrusion 5. The control unit 15 can also use the paper sensor to determine whether or not there is paper P in the roll paper printer 1, and therefore whether or not printing is possible. For example, even if the control unit 15 determines that sensor 6 is near the end, it can continue printing if the paper sensor detects the presence of paper P.

[0041] Incidentally, even after the control unit 15 determines that the roll paper R is near the end, it can continue to display that fact on the display device. Also, the control unit 15 has already sent the near-end information to the computer of the POS system. Therefore, even if the control unit 15 conveys the paper P after determining that the roll paper R is near the end, it does not need to continue detection by the sensor 6. Therefore, after determining that the sensor 6 is near the end, the control unit 15 can stop the emission of the detection light from the sensor 6. Specifically, the control unit 15 stops the supply of power to the sensor 6, or switches the sensor 6 to a mode that stops the operation. As a result, the control unit 15 can control the sensor 6 so that it does not need to perform detection and the sensor 6 saves power. Even when the sensor 6 uses a detection wave, the control unit 15 can stop the sensor 6 from emitting the detection wave after determining that the sensor 6 is near the end.

[0042] The roll paper printer 1 may also be equipped with a switch (not shown) that detects whether the cover 10 is open or closed. If the control unit 15 detects the opening and closing of the cover 10 using the switch after determining that the roll is near the end, it can determine that the user may have opened and closed the cover 10 to set a new roll of paper R in the storage case 12. Therefore, after detecting the opening and closing of the cover 10, the control unit 15 starts detecting the diameter of the roll of paper R using the sensor 6. Then, when the control unit 15 determines that a roll of paper R with a larger diameter has been set and the sensor 6 determines that the roll is not near the end, it can stop the display device from displaying the near-end message.

[0043] Next, as shown in FIG. 4, the roll paper R having a first diameter D1, which is a large diameter, stored in the storage case 12 in the second installation position B is referred to as roll paper RB1. At this time, the exit 13 is located above the roll paper printer 1, and the paper P printed by the head 2 is discharged from above.

[0044] In the case of the roll paper RB1, its outer periphery CB1 comes into contact with the first housing case 12a and the third housing case 12c and is guided from the front-rear direction. Therefore, even when the roller 3 pulls out the paper P from the roll paper RB1 and the roll paper RB1 rotates counterclockwise, the paper can be maintained in a stable position. The sensor 6 can accurately detect the distance X to the outer periphery CB1 of the roll paper RB1. Note that the roll paper RB1 does not come into contact with the support roller 8 located above.

[0045] The detection light from sensor 6 travels in the direction of optical axis 6a and is irradiated onto the outer periphery CB1 of roll paper RB1. The detection light is reflected off the outer periphery CB1 of roll paper RB1 and returns, allowing sensor 6 to detect distance L2 as distance X. Distance L2 is the distance from sensor 6 to the outer periphery CB1 of roll paper RB1.

[0046] As shown in FIG. 5, the roll paper R with the second diameter D2 accommodated in the accommodation case 12 in the second installation position B is referred to as roll paper RB2. As the paper P is printed and transported from roll paper RB1 shown in Figure 4, it becomes roll paper RB2 with a smaller second diameter D2. As the diameter of roll paper RB1 becomes smaller, it moves downward in storage case 12. At this time, it moves from outer circumference CB1 to outer circumference CB2, and the length of the arc that intersects with optical axis 6a at the front and bottom becomes shorter, like the shape of a waning crescent moon.

[0047] In the case of the roll paper RB2, its outer periphery CB2 comes into contact with the concave second housing case 12b and is guided from the front-rear direction. The outer periphery CB2 of the roll paper RB2 may come into contact with and be guided by the first housing case 12a or the third housing case 12c. The second housing case 12b and the like enable the paper P to be kept in a stable position even when the roller 3 pulls out the paper P from the roll paper RB2 and the roll paper RB2 rotates counterclockwise. The sensor 6 can accurately detect the distance X when the outer periphery CB2 of the roll paper RB2 deviates from the optical axis 6a of the detection light.

[0048] When the diameter of the roll paper R changes from the first diameter D1 to the second diameter D2, the outer periphery CB2 of the roll paper RB2 moves to a position off the optical axis 6a of the sensor 6. As a result, when the diameter of the roll paper R becomes the second diameter D2, the outer periphery CB2 of the roll paper RB2 moves off the optical axis 6a of the sensor 6, and the detection light is no longer irradiated onto the outer periphery CB2 of the roll paper RB2.

[0049] The detection light of the sensor 6 travels in the direction of the optical axis 6a, and at this time, the detection light is irradiated onto the fourth housing case 12d or the cover guide 9. In Fig. 5, the distance from the sensor 6 to the fourth housing case 12d or the cover guide 9 is longer than the distance LA over which the detection light is irradiated onto the roll paper RA2 shown in Fig. 3. Therefore, for roll paper RB2, the distance X detected by the sensor 6 is longer than the distance LA. When the diameter of the roll paper R transitions from the first diameter D1 to the second diameter D2, the distance X detected by the sensor 6 gradually increases from the distance L2, and then suddenly changes and becomes longer than the distance LA.

[0050] When the control unit 15 determines that the diameter of the roll paper R is getting smaller and that the distance X detected by the sensor 6 is longer than the distance LA, it can determine that the diameter of the roll paper R has transitioned from the first diameter D1 to the second diameter D2. In other words, the control unit 15 can determine that the roll paper R is near the end. On the other hand, when the sensor 6 detects the distance X that is equal to or less than the distance LA, the control unit 15 can determine that the vehicle is not yet at the near end.

[0051] Next, Figure 6 shows a roll paper RA2 of second diameter D2 stored in storage case 12 in first installation position A of Figure 3, and a virtual stack of roll paper RB2 of second diameter D2 stored in storage case 12 in second installation position B of Figure 5. Regardless of whether the accommodation case 12 is in the first installation position A or the second installation position B, the sensor 6 is in the same position, so that the detection light travels in the same direction along the optical axis 6a.

[0052] When the storage case 12 is in the first installation position A and the roll paper RA2, the detection light of the sensor 6 is irradiated onto the outer periphery CA2 of the roll paper RA2. When the sensor 6 detects the distance LA as the distance X, the control unit 15 can determine that the diameter of the roll paper R has transitioned from the first diameter D1 to the second diameter D2. On the other hand, when the storage case 12 is in the second installation position B for the roll paper RB2, the outer periphery CB2 of the roll paper RB2 deviates from the optical axis 6a of the sensor 6, and the detection light is not irradiated to the outer periphery CB2 of the roll paper RB2. As described above, when the sensor 6 detects the distance X that is longer than the distance LA, the control unit 15 can determine that the diameter of the roll paper R has transitioned from the first diameter D1 to the second diameter D2.

[0053] In other words, regardless of whether the storage case 12 is in the first installation position A or the second installation position B, if the control unit 15 determines that the distance X detected by the sensor 6 is equal to or greater than the distance LA, it can determine that the diameter of the roll paper R has transitioned from the first diameter D1 to the second diameter D2. In other words, when the control unit 15 determines that the relationship between the distance X detected by the sensor 6 and the distance LA is such that distance X≧distance LA, it can determine that the roll paper R is near the end.

[0054] Next, the roll paper printer 1 shown in FIG. 7 shows an example in which the sensor 6 shown in FIGS. The configuration of sensor 7 is the same as that of sensor 6. The distance detected by sensor 7 is defined as distance Y.

[0055] The sensor 7 is disposed on the opposite side of the storage case 12 from the side where the roll paper R is stored so as not to come into contact with the roll paper R. The third housing case 12c is provided with an opening for passing the detection light. The opening may be covered with a resin that allows the detection light to pass through.

[0056] The roll paper printer 1 shown in FIG. 7 is configured the same as in FIGS. 2 to 6, except for the position of the sensor 7. 7, like Fig. 6, shows roll paper RA2 with second diameter D2 housed in storage case 12 in first installation attitude A, and then shows a virtual overlapping of roll paper RB2 with second diameter D2 housed in storage case 12 in second installation attitude B. Fig. 7 will be explained below in comparison with Fig. 6.

[0057] The sensor 7 is in the same position and the detection light of the sensor 7 travels in the direction of the optical axis 7a when the sensor 7 uses a detection wave, regardless of whether the housing case 12 is in the first installation position A or the second installation position B. Note that when the sensor 7 uses a detection wave, the optical axis 7a becomes the propagation path of the detection wave instead of the optical axis 7a. The optical axis 7a of the detection light of the sensor 7 is directed from the third housing case 12c side to the first housing case 12a or the second housing case 12b side. The direction in which the detection light travels along the optical axis 7a of the sensor 7 is substantially opposite to the direction in which the detection light travels along the optical axis 6a of the sensor 6.

[0058] When the container 12 is in the second installation position B, and the diameter of the paper roll RB1 decreases to RB2, the sensor 7 can detect the distance LB as the distance Y. The distance LB is the distance from the sensor 7 to the outer periphery CB2 of the paper roll RB2. The distance LB is, for example, 70 mm. The distance LB may be within a range of 65 mm or more and 75 mm or less. When the sensor 7 detects the distance LB, the control unit 15 can determine that the diameter of the roll paper R has transitioned from the first diameter D1 to the second diameter D2.

[0059] On the other hand, when the diameter of the paper roll RA2 decreases from that of the paper roll RA1 when the paper storage case 12 is in the first installation position A, the outer periphery CA2 of the paper roll RA2 moves out of alignment with the optical axis 7a of the sensor 7. At this time, the detection light of the sensor 7 is not irradiated to the outer periphery CA2 of the paper roll RA2, but is irradiated to the first storage case 12a or the second storage case 12b. The distance from the sensor 7 to the first housing case 12a or the second housing case 12b is longer than the distance LB. Therefore, when the sensor 7 detects a distance Y longer than the distance LB, the control unit 15 can determine that the diameter of the roll paper R has transitioned from the first diameter D1 to the second diameter D2.

[0060] In other words, regardless of whether the storage case 12 is in the first installation position A or the second installation position B, if the control unit 15 determines that the distance Y detected by the sensor 7 is greater than or equal to the distance LB, it can determine that the diameter of the roll paper R has transitioned from the first diameter D1 to the second diameter D2. In other words, when the control unit 15 determines that the relationship between the distance Y and the distance LB detected by the sensor 7 is such that distance Y≧distance LB, it can determine that the roll paper R is near the end.

[0061] Although omitted in Figure 7, similar to the case of sensor 6 described above using Figures 2 and 4, the detection light of sensor 7 can be irradiated onto the outer periphery CA1 of roll paper RA1, and onto the outer periphery CB1 of roll paper RB1, which have a large diameter. Then, just as in the case of sensor 6, when the control unit 15 detects a distance Y that is shorter than distance LB by sensor 7, it can determine that there is a sufficient amount of paper P remaining on the roll paper R and that the roll paper R is not yet near the end.

[0062] 2. How to control a roll paper printer The following describes a case where the above-mentioned roll paper printer 1 is equipped with a sensor 6. The first roll paper R is assumed to be roll paper RA1 with a first diameter D1 that is stored in storage case 12 in first installation position A, or roll paper RB1 with first diameter D1 that is stored in storage case 12 in second installation position B.

[0063] As shown in FIG. 8, first, when the control unit 15 receives print data from the computer of the POS system, the control unit 15 causes the head 2 to print on the paper P, and the rollers 3 to transport the paper P (S100). The control unit 15 detects the distance X by the sensor 6 (S101). The control unit 15 compares the distance X with the distance LA, and determines whether the distance X is equal to or greater than the distance LA (S102). The initial distance X is the distance from the sensor 6 to the outer periphery CA1 of the rolled paper RA1 or the outer periphery CB1 of the rolled paper RB1, each of which has a first diameter D1 that is a large diameter. As the paper P is transported by printing and the diameters become smaller, the distance X also becomes longer.

[0064] When the storage case 12 is in the first installation position A, as the diameter of the roll paper RA1 becomes smaller, the distance X becomes equal to the distance LA, and the equation is distance X = distance LA. At this time, the control unit 15 can determine that the diameter of the roll paper R has transitioned from the first diameter D1 to the second diameter D2. On the other hand, when the storage case 12 is in the second installation position B, as the diameter of the roll paper RB1 becomes smaller, the distance X becomes longer than the distance LA, and the equation distance X>distance LA is satisfied. At this time, the control unit 15 can determine that the diameter of the roll paper R has transitioned from the first diameter D1 to the second diameter D2.

[0065] In other words, the control unit 15 can determine that the distance X is greater than or equal to the distance LA, regardless of whether the storage case 12 is in the first installation position A or the second installation position B, and, in terms of the formula, distance X ≧ distance LA (S102: YES). At this time, the control unit 15 can determine that the diameter of the roll paper R has transitioned from the first diameter D1 to the second diameter D2, and can determine that the roll paper R is near the end.

[0066] The control unit 15 notifies the near-end information by the display device (S103). Specifically, the control unit 15 displays, by the display device, that the remaining amount of paper P is low and that the paper is near-end. The control unit 15 may notify the near-end information by transmitting it to the computer of the POS system. The control unit 15 may stop printing by the head 2 and transportation by the rollers 3. The control unit 15 can also stop the sensor 6 from emitting the detection light.

[0067] On the other hand, when there is a sufficient amount of paper P remaining and the diameter of the roll paper R is large, the distance X is shorter than the distance LA regardless of whether the storage case 12 is in the first installation position A or the second installation position B, and expressed by the formula distance X<distance LA. That is, in any installation posture, if the control unit 15 determines that the distance X is not greater than or equal to the distance LA (S102: NO), it can determine that the paper P is not yet near the end and does not notify the near-end information. The control unit 15 can continue to transport the paper P by the rollers 3 (S100).

[0068] If the roll paper printer 1 is equipped with sensor 7 instead of sensor 6, then in the above description of the control method, distance Y can be substituted for distance X, and distance LB can be substituted for distance LA. The control unit 15 can then make judgments and perform control in the same way as in the case of sensor 6.

[0069] That is, in either installation position, when the control unit 15 detects the distance Y by the sensor 7 and determines that the distance Y is greater than or equal to the distance LB, it can determine that the diameter of the roll paper R has transitioned from the first diameter D1 to the second diameter D2, and can determine that the roll paper R is near the end. The control unit 15 can notify the near-end information. Furthermore, regardless of the installation posture, if the control unit 15 determines that distance Y is not greater than or equal to distance LB, that is, if it determines that distance Y is less than distance LB, it can determine that the device is not yet near the end.

[0070] As described above, the roll paper printer 1 of this embodiment can be installed in a first installation position A or a second installation position B that is different from the first installation position A, and is equipped with a storage case 12 that can store roll paper R around which paper P is wound, and a sensor 6 that can detect the distance X between the outer periphery of the roll paper R by emitting a detection wave or emitting a detection light from the storage case 12 side. The sensor 6 is capable of irradiating detection light or emitting detection waves to the outer circumference of either the roll paper R stored in the storage case 12 in the first installation position A or the outer circumference of the roll paper R stored in the storage case 12 in the second installation position B.

[0071] In a roll paper printer 1 configured in this manner, by having one sensor 6 that can detect the distance X to the outer circumference of the roll paper R, the control unit 15 can determine that the diameter of the roll paper R has transitioned from the first diameter D1 to a second diameter D2 that is smaller than the first diameter D1, and can determine that it is near the end, in either the first installation position A or the second installation position B. The roll paper printer 1 of this embodiment can be simply configured with a single sensor 6. The roll paper printer 1 has a small number of parts, making it possible to make it inexpensive and compact, and there is no need for the user to, for example, move the mechanism that detects the near end.

[0072] Although the present embodiment has been described in detail above with reference to the drawings, the specific configuration is not limited to these embodiments, and may be changed, replaced, deleted, etc. without departing from the gist of the present invention.

[0073] For example, in the above description, the head 2 is described as a thermal head, but the printing method is not limited thereto. For example, the head 2 may be an inkjet head. In this case, since the inkjet head cannot contact the roller 3 to sandwich the paper P, a driven roller that faces the roller 3 and sandwiches the paper P may be mounted on the exterior case 11. [Explanation of symbols]

[0074] 1...roll paper printer, 2...head, 3...roller, 4...paper guide, 5...protrusion, 6,7...sensor, 9...cover guide, 10...cover, 11...exterior case, 12...storage case, 12a...first storage case, 12b...second storage case, 12c...third storage case, 12d...fourth storage case, 13...exhaust port, A...first installation position, B...second installation position, CA1,CA2,CB1,CB2...outer circumference, D1...first diameter, D2...second diameter, F...transport direction, L1,L2,LA,LB,X,Y...distance, P...paper, R,RA1,RA2,RB1,RB2...roll paper.

Claims

1. a storage case that can be installed in a first installation position and a second installation position different from the first installation position and that can store a roll of paper around which paper is wound; a sensor that can detect the distance to the outer periphery of the roll paper by irradiating detection light or transmitting detection waves from the storage case, A roll paper printer, wherein the sensor is capable of irradiating the detection light or emitting the detection wave to the outer periphery of either the roll paper stored in the storage case in the first installation position or the outer periphery of the roll paper stored in the storage case in the second installation position.

2. A roller for transporting the paper is provided, When the housing case is in either the first installation position or the second installation position, When the paper is transported by the roller and the roll paper transitions from a first diameter to a second diameter smaller than the first diameter, The roll paper printer according to claim 1 , wherein the distance detected by the sensor is equal to or greater than a predetermined distance.

3. When the container case is in the first installation position, When the paper is transported by the roller and the roll paper transitions from the first diameter to the second diameter, The roll paper printer according to claim 2 , wherein the distance detected by the sensor is the predetermined distance.

4. The roll paper printer according to claim 3 , wherein the sensor irradiates the detection light or emits the detection wave to the outer periphery of the roll paper when it has the first diameter, and to the outer periphery of the roll paper when it has the second diameter.

5. When the container case is in the second installation position, When the paper is transported by the roller and the roll paper transitions from the first diameter to the second diameter, The roll paper printer according to claim 2 , wherein the distance detected by the sensor is longer than the predetermined distance.

6. 6. The roll paper printer according to claim 5, wherein the sensor irradiates the detection light or emits the detection wave to the outer periphery of the roll paper when the roll paper is at the first diameter, and does not irradiate the detection light or emit the detection wave to the outer periphery of the roll paper after the diameter has shifted to the second diameter.

7. The roll paper printer according to claim 3 or claim 5 , wherein the sensor stops the detection light or the detection wave after the transition to the second diameter.

8. A control method for a roll paper printer comprising: a storage case capable of storing roll paper around which paper is wound in either a first installation position or a second installation position different from the first installation position; a sensor capable of irradiating detection light or emitting detection waves to the outer periphery of either the roll paper stored in the storage case in the first installation position or the roll paper stored in the storage case in the second installation position and capable of detecting the distance between the roll paper; and a roller that transports the paper, A control method for a roll paper printer in which, regardless of whether the storage case is in the first installation position or the second installation position, the paper is transported by the roller, and when the distance detected by the sensor becomes equal to or greater than a predetermined distance, it is determined that the roll paper has transitioned from a first diameter to a second diameter smaller than the first diameter.

Images