Printer

Abstract

To provide a throw-in type printer capable of detecting a residual amount of a recording paper sheet that is stored therein.SOLUTION: There is provided a printer comprising a medium storage part in which a roll body including a recording paper sheet wound in a roll shape is stored, a printing head for performing printing on the recording paper sheet pulled out from the roll body via rotation, and a residual amount detection circuit for detecting a residual amount of the recording paper sheet stored in the medium storage part. The medium storage part stores the roll body in such a manner that a center position of the roll body is varied in accordance with pulling-out of the recording paper sheet from the roll body. The residual amount detection circuit comprises: an optical type tracking sensor for irradiating a detection face of the roll body crossing a rotation axis of the roll body with light and detecting light reflected thereon; and a determination circuit for determining the residual amount of the recording paper sheet based on a detection result of the optical type tracking sensor.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present invention relates to a printing device. [Background technology]

[0002] Patent Document 1 discloses a device that prints on roll paper, in which the roll paper is fixed to a paper tube and the remaining amount of roll paper is detected from the rotation speed of the paper tube. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2005-247568 Summary of the Invention [Problem to be solved by the invention]

[0004] However, the technology described in Patent Document 1 cannot be applied to the throw-in type printing devices that have become popular in recent years, and there is room for improvement. [Means for solving the problem]

[0005] One aspect of the printing device according to the present invention is a medium storage section that stores a roll of recording paper; a print head that prints on the recording paper pulled out from the roll by rotation; a remaining amount detection circuit for detecting the remaining amount of the recording paper accommodated in the medium accommodation unit; Equipped with the medium storage unit stores the roll body so that the center position of the roll body changes as the recording paper is pulled out from the roll body, The remaining amount detection circuit an optical tracking sensor that irradiates light onto a detection surface of the roll body that intersects with the rotation axis of the roll body and detects reflected light; a determination circuit that determines the remaining amount of the recording paper based on the detection result of the optical tracking sensor; It has. [Brief explanation of the drawings]

[0006] [Figure 1] FIG. 1 is a perspective view illustrating an example of the external structure of a printing device. [Figure 2] FIG. 2 is a diagram illustrating an example of the internal structure of a printing device. [Figure 3] 10A and 10B are diagrams for explaining the movement of the roll body when the recording paper is pulled out. [Figure 4] FIG. 2 illustrates an example of a functional configuration of a printing apparatus. [Figure 5] FIG. 2 is a diagram illustrating an example of the configuration of a remaining amount detection circuit. [Figure 6] 10A and 10B are diagrams for explaining a specific example of a method for generating shift amounts dtx and dty in a DSP. [Figure 7] 10 is a diagram for explaining the relationship between the movement amounts dtx and dty and the remaining amount of recording paper. FIG. [Figure 8] FIG. 10 is a diagram illustrating a fixed position of a remaining medium sensor that satisfies a first condition. [Figure 9] FIG. 10 is a diagram illustrating a fixed position of the remaining medium sensor that satisfies the second condition. [Figure 10] FIG. 10 is a diagram illustrating a fixed position of the remaining medium sensor that satisfies the third condition. [Figure 11] FIG. 10 is a diagram showing an example of an irradiation area IR. DETAILED DESCRIPTION OF THE INVENTION

[0007] Preferred embodiments of the present invention will be described below with reference to the drawings. The drawings used are for the convenience of explanation. Note that the embodiments described below do not unduly limit the content of the present invention as defined in the claims. Furthermore, not all of the configurations described below are necessarily essential components of the present invention.

[0008] 1. General structure of the printing device The printing device 1 of this embodiment will be described as a so-called thermal printer that executes a printing process to form an image on recording paper P, such as thermal paper. Note that the printing device 1 is not limited to a thermal printer and may be an inkjet printer or a laser printer. The schematic structure of the printing device 1 of this embodiment will be described. FIG. 1 is a perspective view showing an example of the exterior structure of the printing device 1. The following description will be given using mutually perpendicular X, Y, and Z axes. In the following description, the starting side of an arrow along the illustrated X axis will be referred to as the -X side, and the tip side will be referred to as the +X side. The starting side of an arrow along the illustrated Y axis will be referred to as the -Y side, and the tip side will be referred to as the +Y side. The starting side of an arrow along the illustrated Z axis will be referred to as the -Z side, and the tip side will be referred to as the +Z side.

[0009] As shown in FIG. 1, the printing device 1 has a main body case 2, an opening / closing door 3, an outlet 4, a notification unit 5, a power switch 6, and an opening / closing lever 7.

[0010] The main body case 2 has a generally rectangular parallelepiped shape overall, excluding bumps and recesses such as buttons. Recording paper P is stored inside this main body case 2. In the printing device 1 of this embodiment, opposing faces of the roughly rectangular parallelepiped main body case 2 face each other along the X-axis, Y-axis, and Z-axis.

[0011] The opening / closing door 3 forms part of the +Y side surface of the main body case 2. It is provided on the +Y side surface of the main body case 2 so as to be able to open and close. The opening / closing lever 7 is located near the opening / closing door 3, and in the printing device 1 of this embodiment, it is located on the +Z side of the opening / closing door 3. The user operates the opening / closing lever 7 and opens the opening / closing door 3 using the hinge portion 8 shown in FIG. 2 as the rotation axis. This allows the user to access the inside of the main body case 2, and the user places recording paper P in the media storage unit 30 (described later) provided inside the main body case 2.

[0012] The discharge outlet 4 is located on the +Y side of the main body case 2 and on the +Z side of the opening and closing door 3, and is inserted into the inside of the main body case 2. The recording paper P printed inside the main body case 2 of the printing device 1 is discharged to the outside of the printing device 1 through the discharge outlet 4.

[0013] The notification unit 5 includes, for example, multiple LEDs. The notification unit 5 displays information about the status of the printing device 1 by flashing, lighting, or turning off the LEDs. Specifically, the notification unit 5 notifies the user of the status of the printing device 1, such as information about the printing status of the printing device 1, information about the communication status of the printing device 1, and information about the recording paper P being printed by the printing device 1. Because the notification unit 5 serves to notify the user of the status of the printing device 1, it is preferably located in a position that is easily visible to the user, such as near the discharge port 4. Note that the notification unit 5 is not limited to multiple LEDs and may be a liquid crystal display device, or may be configured to notify the user of information by sound such as a buzzer or speaker. The notification unit 5 may also be a so-called touch panel that combines an operation panel for executing various settings and operations of the printing device 1 with a liquid crystal display device.

[0014] The power switch 6 is located on the +Y side of the main body case 2, on the opening and closing door 3. The power switch 6 accepts operations to start and / or stop the printing device 1. By operating this power switch 6, for example, at least one of starting and / or stopping of the printing device 1 may be controlled by switching whether or not power supplied to the printing device 1 via a power cable (not shown) is supplied to various components of the printing device 1, or by restricting the printing process on the recording paper P or communication with external devices connected to the printing device 1, thereby controlling at least one of starting and / or stopping of the printing device 1.

[0015] 2 is a diagram schematically illustrating an example of the internal structure of the printing device 1, showing the interior of the printing device 1 as viewed from the +X side along the X axis. As shown in FIG. 2, the printing device 1 has, inside the main body case 2, a transport roller 12, a movable blade 14a, a fixed blade 14b, a paper detection sensor 15, an encoder 16, an open / close sensor 19, a remaining media sensor 20, a media storage unit 30, and a print head 200.

[0016] The medium storage unit 30 stores a roll R containing recording paper P wound into a roll. In the printing device 1 of this embodiment, the medium storage unit 30 uses a so-called throw-in method, which allows the roll R to be stored simply by throwing it in without being fixed to a holding mechanism. This allows the user to easily set the roll R in the printing device 1.

[0017] The roll R includes recording paper P and a core C. The core C is a substantially cylindrical shape with a hollow H formed in the center. The roll R is formed by winding the recording paper P around the core C in a roll shape. That is, the roll R includes the core C around which the recording paper P is wound. The roll R configured as described above is stored in the medium storage unit 30 so that the hollow H of the core C extends along the X-axis. Then, the recording paper P is pulled out from the roll R by the rotation of the transport roller 12, which will be described later. At this time, the roll R rotates around the axis along which the hollow H of the core C extends. Hereinafter, the direction of the roll R along the axis along which the hollow H of the core C extends will be referred to as the width direction of the roll R, and the surface of the roll R normal to the axis along which the hollow H of the core C extends will sometimes be referred to as the side of the roll R. That is, in the printing device 1 of this embodiment shown in Figure 2, the roll R is stored in the medium storage unit 30 so that its width direction extends along the X axis and its side extends along the plane formed by the Y axis and Z axis. Here, the side of the roll R is the surface formed by the recording paper P and the core C, and does not include the cavity H of the core C. Alternatively, the roll R may not include the core C, and the recording paper P may be wound into a roll. In this case, the side of the roll R is the surface formed by the recording paper P, and does not include the cavity H of the core C.

[0018] The medium storage unit 30 includes support members 31, 32, 33, 34, and 35 that support the outer periphery of the roll R. The support member 31 is a plate-shaped member and is arranged so that its long side is aligned along the X-axis and its short side is aligned along the Y-axis. The support member 32 is a plate-shaped member located on the +Y side of the support member 31 and on the +Z side of the support member 31, with its long side aligned along the X-axis and its short side inclined toward the support member 31 by its end on the +Y side being closer to the +Z side than its end on the -Y side in the plane formed by the Y and Z axes. The support member 33 is a plate-shaped member located on the -Y side of the support member 31 and on the +Z side of the support member 31, with its long side aligned along the X-axis and its short side inclined toward the support member 31 by its end on the -Y side being closer to the +Z side than its end on the +Y side in the plane formed by the Y and Z axes. Support member 34 is a plate-like member whose long side is positioned along the X-axis and whose short side is positioned such that, in the plane formed by the Y-axis and Z-axis, the +Y-side end is positioned closer to the +Z side than the -Y-side end. Support member 34 is positioned so that its +Y-side long side contacts the -Y-side long side of support member 32 and its -Y-side long side contacts the +Y-side long side of support member 31. That is, support member 34 is provided so as to incline from support member 32 toward support member 31. Support member 35 is a plate-like member whose long side is positioned along the X-axis and whose short side is positioned such that, in the plane formed by the Y-axis and Z-axis, its -Y-side end is positioned closer to the +Z side than the +Y-side end. Support member 35 is positioned so that its -Y-side long side contacts the +Y-side long side of support member 33 and its +Y-side long side contacts the -Y-side long side of support member 31. That is, the support member 35 is provided so as to be inclined from the support member 33 toward the support member 31 .

[0019] In the medium storage section 30 configured as described above, the position along the Z axis of the +Y side end of support member 32 is approximately equal to the position along the Z axis of the -Y side end of support member 33, the acute angle of the inclination angle of support member 32 relative to the Y axis is approximately equal to the acute angle of the inclination angle of support member 33 relative to the Y axis, the acute angle of the inclination angle of support member 34 relative to the Y axis is approximately equal to the acute angle of the inclination angle of support member 35 relative to the Y axis, and the acute angle of the inclination angle of support member 34 relative to the Y axis and the acute angle of the inclination angle of support member 35 relative to the Y axis are larger than the acute angle of the inclination angle of support member 32 relative to the Y axis and the acute angle of the inclination angle of support member 33 relative to the Y axis, and support members 31, 32, 33, 34, and 35 are positioned so that

[0020] That is, medium container 30 includes a recess having an opening on the +Z side formed by including support members 32 and 33, and a recess located on the -Z side of the recess and having an opening on the +Z side formed by including support members 31, 34, and 35. Hereinafter, the recess formed by support members 32 and 33 may be referred to as a first recess, and the recess formed by support members 31, 34, and 35 may be referred to as a second recess. Note that support members 31, 32, 33, 34, and 35 constituting medium container 30 may each be an independent plate-like structure, or one or more structures may be formed by bending a single plate-like member.

[0021] In a printing device 1 employing a throw-in method, such as the printing device 1 of this embodiment, the position of the roll R may change significantly as the recording paper P is pulled out from the roll R. In contrast, in the printing device 1 of this embodiment, the medium storage unit 30 has a first recess formed by support members 32 and 33, and a second recess formed by support members 31, 34, and 35, which reduces the risk of the center position of the roll R changing significantly when the recording paper P is pulled out from the roll R.

[0022] FIG. 3 is a diagram for explaining the movement of the roll body R accompanying the pulling out of the recording paper P. As shown in FIG.

[0023] When the roll R with the largest remaining amount of recording paper P, for example, an unused roll R, is stored in the medium storage unit 30, the roll R is stored in the medium storage unit 30 at storage position r1. At this time, the roll R is supported by support members 32 and 33. As described above, support members 32 and 33 are each arranged to incline toward support member 31. The position of the +Y end of support member 32 along the Z axis is approximately equal to the position of the −Y end of support member 33 along the Z axis, and the acute angle of the inclination of support member 32 with respect to the X axis is approximately equal to the acute angle of the inclination of support member 33 with respect to the X axis. Therefore, when the roll R is stored in storage position r1, the center ce1, which is the center position of the roll R, is located on or near the central axis ax, where the distance from the +Y end of support member 32 is equal to the distance from the −Y end of support member 33.

[0024] Furthermore, when the remaining amount of wound recording paper P decreases as a result of the recording paper P being pulled out from the roll R, the roll R is stored in the medium storage unit 30 at storage position r2. Even in this case, the roll R is supported by support members 32 and 33. Therefore, the center ce2, which is the central position of the roll R when the roll R is stored at storage position r2, is also located on or near the central axis ax.

[0025] Similarly, when the roll R is stored at storage position r2, if further recording paper P is pulled out from the roll R, further reducing the remaining amount of wound recording paper P, the roll R is stored in the medium storage unit 30 at storage position r3, and if further recording paper P is pulled out from the roll R, further reducing the remaining amount of wound recording paper P, the roll R is stored in the medium storage unit 30 at storage position r4. Even in this case, the roll R is supported by the support members 32 and 33. Therefore, the centers ce3 and ce4, which are the central positions of the roll R when the roll R is stored at storage positions r3 and r4, are also located on or near the central axis ax.

[0026] As described above, in the printing device 1 of this embodiment, even when recording paper P is pulled out from the roll R, the center position of the roll R is located on or near the central axis ax while the roll R is housed in the first recess of the medium housing unit 30 because the roll R is supported by the support members 32 and 33. In other words, even when recording paper P is pulled out from the roll R, the medium housing unit 30 houses the roll R without the center position of the roll R moving significantly away from the central axis ax.

[0027] Furthermore, when the recording paper P is further pulled out from the roll R while the roll R is stored in the storage position r4, the roll R is supported by the support member 31. At this time, the weight of the roll R becomes smaller relative to the force pulling the recording paper P out of the roll R, which may result in irregular movement of the roll R. To prevent such irregular movement of the roll R, the medium storage unit 30 of this embodiment has a second recess smaller than the first recess located on the -Z side of the first recess and along the central axis ax. This second recess limits the irregular movement of the roll R. As a result, even if irregular movement of the roll R occurs as the weight of the roll R decreases, the risk of the center position of the roll R moving significantly away from the central axis ax is reduced.

[0028] As described above, in the printing device 1 of this embodiment, the medium storage unit 30 has a first recess formed by support members 32 and 33, and a second recess formed by support members 31, 34, and 35. This reduces the risk that the center position of the roll R will deviate significantly from the central axis ax when recording paper P is pulled out from the roll R. Whether the roll R is held in the first recess or the second recess can be determined based on the weight of the roll R and the strength with which recording paper P is pulled out from the roll R by appropriately adjusting the distance between the +Y side end of the support member 32 and the -Y side end of the support member 33.

[0029] As described above, medium storage unit 30 stores roll R so that the center position changes along the axis as recording paper P is pulled out from roll R. Furthermore, when the diameter of roll R stored in medium storage unit 30 is greater than the distance between the +Y side end of support member 32 and the -Y side end of support member 33, roll R is supported by support members 32 and 33 and does not come into contact with support member 31, and when the diameter of roll R stored in medium storage unit 30 is smaller than the distance between the +X side end of support member 32 and the -X side end of support member 33, roll R is supported by support member 31.

[0030] Returning to FIG. 2 , the transport roller 12 is located on the -Y side of the opening / closing door 3, on the -Z side of the transport path along which the recording paper P is transported, and the print head 200 is located opposite the transport roller 12 with the recording paper P interposed between them. The transport roller 12 and the print head 200 hold the recording paper P pulled out from the roll R. When a motor (not shown) is driven to rotate, the transport roller 12 rotates, and the rotation of the transport roller 12 transports the recording paper P held between the transport roller 12 and the print head 200. In other words, the recording paper P is pulled out from the roll R, and the pulled-out recording paper P is transported toward the print head 200.

[0031] The transport roller 12 is provided with an encoder 16. The encoder 16 includes a disk 17 and a photosensor 18. The disk 17 has multiple slits formed on its periphery and is fixed to the transport roller 12 so that its central axis coincides with the rotation axis of the transport roller 12. In other words, the disk 17 rotates as the transport roller 12 rotates. The photosensor 18 is provided facing the periphery of the disk 17. The photosensor 18 is fixed to, for example, the main body case 2, in a location where its position does not change even when the transport roller 12 rotates. The photosensor 18 obtains, in binary form, a change in the amount of light that occurs when the transport roller 12 passes through each slit formed on the periphery of the disk 17 as the transport roller 12 rotates. The photosensor 18 then generates a pulse signal corresponding to the obtained change in the amount of light. The encoder 16 outputs the pulse signal generated by the photosensor 18.

[0032] The print head 200 applies heat to the recording paper P held between the print head 200 and the transport roller 12 at a timing synchronized with the pulse signal output by the encoder 16. In other words, the print head 200 performs printing by applying heat to the recording paper P pulled out from the roll R by rotation at a timing corresponding to the transport of the recording paper P by the transport roller 12. In this way, the desired image is printed on the recording paper P.

[0033] The movable blade 14a and the fixed blade 14b are located closer to the discharge port 4 than the print head 200 along the transport path of the recording paper P transported by the transport roller 12. Specifically, the movable blade 14a is located on the +Y side of the transport roller 12 and the print head 200 and on the -Z side of the recording paper P transported by the transport roller 12, while the fixed blade 14b is located on the +Y side of the transport roller 12 and the print head 200 and on the +Z side of the recording paper P transported by the transport roller 12. When the movable blade 14a moves toward the +Z side along the Z axis, the recording paper P is sandwiched between the movable blade 14a and the fixed blade 14b and cut. At this time, the movable blade 14a and the fixed blade 14b may perform a so-called partial cut, in which a portion of the recording paper P is left uncut, or may perform a so-called full cut, in which the recording paper P is completely cut. The recording paper P cut by the movable blade 14a and the fixed blade 14b is then discharged from the discharge port 4.

[0034] The paper detection sensor 15 is provided near the discharge outlet 4 and detects the presence or absence of recording paper P near the discharge outlet 4. For example, if the paper detection sensor 15 detects that recording paper P is near the discharge outlet 4 even after a predetermined time has elapsed since the printing process was completed, the paper detection sensor 15 notifies the user by displaying on the notification unit 5 that the recording paper P remains uncut.

[0035] The opening / closing sensor 19 is provided near the opening / closing door 3 and detects whether the opening / closing door 3 is open or closed. The opening / closing sensor 19 may be, for example, a mechanical switch that turns on or off in conjunction with the opening or closing of the opening / closing door 3, or a photosensor that changes the amount of light it receives in a binary manner in conjunction with the opening or closing of the opening / closing door 3. When the opening / closing sensor 19 detects that the opening / closing door 3 is open, it notifies the user via the notification unit 5 that the opening / closing door 3 is open. At this time, the print head 200 may stop executing the printing process.

[0036] The medium remaining amount sensor 20 is fixed to the main body case 2 near the recording paper P stored in the medium storage unit 30. The medium remaining amount sensor 20 detects the amount of movement of the side of the roll R stored in the medium storage unit 30. The printing device 1 detects the remaining amount of the roll R stored in the medium storage unit 30, that is, the remaining amount of recording paper P contained in the roll R stored in the medium storage unit 30, based on the amount of movement of the side of the roll R detected by the medium remaining amount sensor 20. Details of the medium remaining amount sensor 20 and a method for detecting the remaining amount of the roll R, that is, the remaining amount of recording paper P contained in the roll R, based on the amount of movement of the side of the roll R, will be described later.

[0037] 2. Functional configuration of the printing device Next, the functional configuration of the printing device 1 will be described. Fig. 4 is a diagram showing an example of the functional configuration of the printing device 1. As described above, the printing device 1 of this embodiment is a so-called thermal printer that prints on recording paper P, such as thermal paper, by applying heat to a desired position on the medium. As shown in Fig. 4, the printing device 1 includes a main control circuit 100, a power input IF 110, a power generation circuit 120, a printing unit 150, an external IF 160, a power switch 6, an alarm unit 5, a paper detection sensor 15, an open / close sensor 19, and a remaining amount detection circuit 170.

[0038] A DC voltage signal Vd is supplied to the printing device 1 via the power input IF 110. The voltage signal Vd is input to the power generation circuit 120. The power generation circuit 120 converts the input voltage signal Vd into a voltage value used by various components of the printing device 1 by stepping up or down the voltage. The power generation circuit 120 then outputs a constant voltage signal Vdd at the converted voltage value to the corresponding components. Such a power generation circuit 120 includes a DC-DC converter. Here, the power generation circuit 120 may generate a constant voltage signal Vdd at a voltage value corresponding to each of the various components of the printing device 1 and output it to the corresponding components. In other words, the power generation circuit 120 may output multiple voltage signals Vdd with different voltage values, or may include multiple DC-DC converters that output multiple voltage signals Vdd.

[0039] The power switch 6 generates a power signal Pw requesting the start or stop of the printing device 1 in response to a user operation, and outputs the power signal Pw to the main control circuit 100.

[0040] The main control circuit 100 receives as input a voltage signal Vdd output by the power generation circuit 120 and a power signal Pw output by the power switch 6. When the voltage signal Vdd is being input, the main control circuit 100 starts operating when the power switch 6 inputs a power signal Pw requesting startup of the printing device 1.

[0041] The main control circuit 100 also receives a communication information signal CS via the external IF 160 for communication with an external device located outside the printing device 1. The main control circuit 100 outputs signals for controlling various components of the printing device 1 in response to the received communication information signal CS. The main control circuit 100 also generates a communication information signal CS for controlling the operation of the external device and outputs the signal to the external device via the external IF 160. That is, the main control circuit 100 and the external device located outside the printing device 1 are connected via the external IF 160 for bidirectional communication. The external IF 160 may be a wireless communication module that converts signals received from the external device in accordance with the communication information signal CS into signals conforming to a communication standard such as Wi-Fi or Bluetooth, or a wired communication module that converts signals received from the external device in accordance with the communication information signal CS into signals conforming to a communication standard such as USB (Universal Serial Bus) communication. Examples of external devices that can be used include a personal computer, tablet device, or POS (Point of Sale) terminal that causes the printing device 1 to print.

[0042] When a communication information signal CS for executing a printing process is input from an external device via the external IF 160, the main control circuit 100 outputs a print control signal Pc to the printing unit 150 to cause the printing unit 150 to print information corresponding to the communication information signal CS.

[0043] The printing unit 150 receives a print control signal Pc output by the main control circuit 100 and a voltage signal Vdd output by the power supply generating circuit 120. The printing unit 150 uses the voltage signal Vdd as a drive voltage to execute a printing process for printing information corresponding to the print control signal Pc onto recording paper P.

[0044] The printing unit 150 includes a head control circuit 220, a transport control circuit 230, a cutting control circuit 240, and a print head 200. The print head 200 also includes a plurality of heat generating elements 210.

[0045] The transport control circuit 230 controls the transport of the recording paper P in response to a print control signal Pc input from the main control circuit 100. Specifically, the transport control circuit 230 controls the rotation of the transport roller 12 by controlling the rotation drive of a motor (not shown) in response to the input print control signal Pc. This causes the recording paper P to be pulled out from the roll R.

[0046] The cutting control circuit 240 cuts the recording paper P to a predetermined size in response to the print control signal Pc input from the main control circuit 100. Specifically, the transport control circuit 230 moves the movable blade 14a to -Z shown in FIG. 2 at a timing determined by the input print control signal Pc. As a result, the recording paper P transported by the rotation of the transport roller 12 is sandwiched between the movable blade 14a and the fixed blade 14b. As a result, the recording paper P is cut to a predetermined size. Here, the cutting control circuit 240 may control the timing of moving the movable blade 14a in response to the pulse signal output by the encoder 16 in addition to the input print control signal Pc.

[0047] The head control circuit 220 outputs a drive signal Drv corresponding to each of the multiple heating elements 210 in the print head 200 in response to a print control signal Pc input from the main control circuit 100. This controls the drive state of each of the heating elements 210, and whether or not each of the heating elements 210 generates heat. Specifically, the head control circuit 220 generates a drive signal Drv corresponding to each of the multiple heating elements 210 in response to the input print control signal Pc. The head control circuit 220 then outputs the drive signal Drv to each of the corresponding heating elements 210 at a timing that corresponds to the pulse signal output by the encoder 16.

[0048] In the printing unit 150 configured as described above, the multiple heating elements 210 of the print head 200 are aligned along the X-axis shown in FIG. 2 , in a direction perpendicular to the transport direction of the recording paper P. The transport control circuit 230 controls the transport of the recording paper P based on the print control signal Pc, and the head control circuit 220 outputs drive signals Drv corresponding to each of the multiple heating elements 210 based on the print control signal Pc. That is, the head control circuit 220 outputs drive signals Drv corresponding to each of the multiple heating elements 210 at timing synchronized with the transport of the recording paper P. As a result, heat generated by the heat generating elements 210 is applied to desired positions on the transported recording paper P. As a result, characters and images containing desired information are formed on the recording paper P. The recording paper P with the characters and images containing the desired information formed thereon is then cut to a predetermined size by the cutting control circuit 240, and the recording paper P of the predetermined size and with the desired information printed on it is discharged from the discharge opening 4.

[0049] Furthermore, the main control circuit 100 generates a notification information signal Cd according to the state of the printing device 1 and outputs it to the notification unit 5. The notification unit 5 notifies the user of the printing device 1 of information according to the input notification information signal Cd. This allows the user to understand the state of the printing device 1.

[0050] The paper detection sensor 15 detects whether or not there is recording paper P near the discharge outlet 4. If recording paper P is still present near the discharge outlet 4 even after a predetermined period of time has elapsed since the printing process in the printing unit 150 was completed, the paper detection sensor 15 generates a remaining information signal Ps to notify the user that the recording paper P for which printing process has been completed has been left behind, and outputs the signal to the main control circuit 100. The main control circuit 100 generates a notification information signal Cd in response to the remaining information signal Ps that is input, and outputs the signal to the notification unit 5. This notifies the user that the recording paper P has been left behind.

[0051] The opening / closing sensor 19 detects whether the opening / closing door 3 is open. The opening / closing sensor 19 generates an opening / closing information signal Os according to whether the opening / closing door 3 is open or not, and outputs the signal to the main control circuit 100. When the main control circuit 100 determines that the opening / closing door 3 is open according to the opening / closing information signal Os, it generates a print control signal Pc for stopping the execution of the printing process in the printing unit 150 and outputs the signal to the printing unit 150, and also generates a notification information signal Cd for notifying that the opening / closing door 3 is open and outputs the signal to the notification unit 5. This notifies the user of warning information that the opening / closing door 3 is open.

[0052] The remaining amount detection circuit 170 includes the above-mentioned medium remaining amount sensor 20. The remaining amount detection circuit 170 uses the medium remaining amount sensor 20 to detect the remaining amount of recording paper P contained in the roll R stored in the medium storage unit 30. The remaining amount detection circuit 170 then generates a remaining amount information signal Rs corresponding to the remaining amount of recording paper P contained in the roll R stored in the medium storage unit 30, and outputs the signal to the main control circuit 100.

[0053] The main control circuit 100 generates a notification information signal Cd in response to the input remaining amount information signal Rs and outputs it to the notification unit 5. This notifies the user of the remaining amount of recording paper P contained in the roll R stored in the medium storage unit 30. Here, the main control circuit 100 may generate a notification information signal Cd for notifying the user of the remaining amount of recording paper P contained in the roll R stored in the medium storage unit 30 and output it to the notification unit 5, or may generate a notification information signal Cd for notifying the user of whether the remaining amount of recording paper P contained in the roll R stored in the medium storage unit 30 is sufficient, insufficient, or whether the recording paper P has run out and output it to the notification unit 5.

[0054] 3. Functional configuration of the remaining amount detection circuit Here, a specific example of the configuration of the remaining amount detection circuit 170 that detects the remaining amount of recording paper P contained in the roll R stored in the medium storage unit 30 will be described. FIG. 5 is a diagram showing an example of the configuration of the remaining amount detection circuit 170. As shown in FIG. 5, the remaining amount detection circuit 170 has a media remaining amount sensor 20 and a determination circuit 175. The media remaining amount sensor 20 also has a light-emitting element 21, a light-receiving unit 22, and a DSP (Digital Signal Processor) 23. Here, the media remaining amount sensor 20 may be configured as a single integrated circuit device including the light-emitting element 21, the light-receiving unit 22, and the DSP 23. The determination circuit 175 may also be configured as a separate integrated circuit device, or may be configured together with the media remaining amount sensor 20 as a single integrated circuit device, or may be configured together with the main control circuit 100 as a single integrated circuit device.

[0055] The light emitting element 21 includes a vertical cavity surface emitting laser (VCSEL) and emits laser light IL having a peak at a specific wavelength such as 850 nm. The laser light IL emitted by the light emitting element 21 is irradiated onto one side of the roll body R.

[0056] The light receiving unit 22 includes a plurality of light receiving elements 24. In the light receiving unit 22, the plurality of light receiving elements 24 are arranged in a plurality of rows and a plurality of columns. In this case, the plurality of light receiving elements 24 may be arranged, for example, in a square lattice pattern or a triangular lattice pattern. Each of the plurality of light receiving elements 24 included in the light receiving unit 22 detects reflected light RL, which is laser light IL reflected by the side surface of the roll body R. The light receiving unit 22 then generates a detection light information signal LR including detection information DI corresponding to the reflected light RL detected by each of the plurality of light receiving elements 24, and outputs the detection light information signal LR to the DSP 23. Here, the detection information DI corresponding to the reflected light RL detected by the light receiving elements 24 may be information on the intensity of the reflected light RL, information on the wavelength of the reflected light RL, or information on the intensity of a specific wavelength included in the reflected light RL.

[0057] The DSP23 acquires detection information DI detected by each of the plurality of light receiving elements 24 based on the input detection light information signal LR. Then, the DSP23 calculates image information corresponding to the reflected light RL reflected on the side surface of the roll body R by arranging the acquired detection information DI detected by each of the plurality of light receiving elements 24 according to the arrangement of the plurality of light receiving elements 24 in the light receiving unit 22. That is, the DSP23 calculates image information in which the detection information DI detected by each of the plurality of light receiving elements 24 is arranged as pixel information. At this time, so-called speckles such as interference fringes and spot patterns caused by interference and diffraction occurring in accordance with the light output from the light emitting element 21 appear in the image corresponding to the image information calculated by the DSP23.

[0058] At any time t1, the DSP23 calculates image information corresponding to the reflected light RL detected by each of the multiple light receiving elements 24 when the laser light IL is irradiated onto the side surface of the roll R, and at any time t2 after time t1, calculates image information corresponding to the reflected light RL detected by each of the multiple light receiving elements 24 when the laser light IL is irradiated onto the side surface of the roll R. The DSP23 then compares the image information calculated at time t1 with the image information calculated at time t2 to generate a movement amount dtx of the roll R in a direction along an arbitrary first axis x and a movement amount dty of the roll R in a direction along a second axis y perpendicular to the arbitrary first axis x, which are the rotational speed of the roll R stored in the medium storage unit 30. The medium remaining amount sensor 20 then outputs the movement amounts dtx and dty generated by the DSP23. Here, the first axis x and the second axis y are axes that extend in directions independent of the above-mentioned axes X, Y, and Z, are axes along which the cavity H of the core material C extends, and are axes that intersect with the rotation axis around which the roll body R rotates, and are determined based on the fixed position and fixed angle of the media remaining sensor 20 fixed to the printing device 1 or the main body case 2.

[0059] As described above, the media remaining amount sensor 20 irradiates laser light IL, an example of light, onto the side of the roll body R, which is a surface that intersects with the rotation axis of the roll body R and has the axis along which the cavity H of the core material C extends as its normal direction, and detects the reflected light RL.

[0060] A specific example of a method for generating the shift amounts dtx and dty in the DSP 23 will be described below. FIG. 6 is a diagram for explaining a specific example of a method for generating the shift amounts dtx and dty in the DSP 23.

[0061] At time t1, when the laser light IL is irradiated onto the side surface of the roll body R, the DSP23 calculates image information corresponding to the reflected light RL detected by each of the multiple light receiving elements 24. FIG. 6(a) shows an example of an image corresponding to the image information calculated by the DSP23 at time t1. The DSP23 extracts pixels that become feature points SPa that occur due to the side surface of the roll body R and speckles from the image information acquired at time t1. At this time, the feature points SPa extracted by the DSP23 may be, for example, pixels whose pixel information of a specific pixel included in the image information is significantly different from that of neighboring pixels, or pixels whose pixel information included in the image information is a predetermined specific value.

[0062] Furthermore, at time t2, the DSP23 calculates image information corresponding to the reflected light RL detected by each of the plurality of light receiving elements 24 when the laser light IL is irradiated onto the side surface of the roll body R. FIG. 6(b) shows an example of an image corresponding to the image information calculated by the DSP23 at time t2. The DSP23 extracts a pixel that becomes the feature point SPb corresponding to the feature point SPa extracted at time t1 from the image information acquired at time t2. At this time, the DSP23 may extract the feature point SPb corresponding to the feature point SPa by, for example, using the same method under the same conditions as when extracting the feature point SPa.

[0063] Then, DSP23 outputs the difference between the position along the first axis x of feature point SPa included in the image information acquired at time t1 and the position along the first axis x of feature point SPb included in the image information acquired at time t2 as a movement amount dtx, and outputs the difference between the position along the second axis y of feature point SPa included in the image information acquired at time t1 and the position along the second axis y of feature point SPb included in the image information acquired at time t2 as a movement amount dty.

[0064] Here, the DSP23 may extract a plurality of feature points SPa from the image information acquired at time t1, and may extract a plurality of feature points SPb corresponding to the plurality of feature points SPa from the image information acquired at time t2, output an average value or a representative value of the difference in position between each of the feature points SPa and SPb along the first axis x as the movement amount dtx, and output an average value or a representative value of the difference in position between each of the feature points SPa and SPb along the second axis y as the movement amount dty.

[0065] The medium remaining amount sensor 20 configured as described above irradiates the laser light IL output by the light emitting element 21 onto the roll R, which is the test object. The medium remaining amount sensor 20 also detects the reflected light RL reflected by the roll R, which is the test object, to detect at least one of information about the side surface of the roll R contained in the reflected light RL and speckles. The medium remaining amount sensor 20 then obtains the amount of movement of the roll R, which is the test object, based on the detection results. An optical tracking sensor can be used as this medium remaining amount sensor 20.

[0066] Returning to FIG. 5, the movement amounts dtx and dty output by the remaining medium sensor 20 are input to the determination circuit 175. The determination circuit 175 estimates the remaining amount of recording paper P contained in the roll R based on the input movement amounts dtx and dty. The determination circuit 175 then generates a remaining amount information signal Rs corresponding to information on the estimated remaining amount of recording paper P contained in the roll R. The remaining amount information signal Rs generated by the determination circuit 175 is output from the remaining amount detection circuit 170. In other words, the determination circuit 175 determines the remaining amount of recording paper P contained in the roll R based on at least one of the detection results output by the remaining medium sensor 20, namely, the movement amount dtx, which is the amount the roll R moves in the direction along the first axis x, and the movement amount dty, which is the amount the roll R moves in the direction along the second axis y, which is perpendicular to the first axis x.

[0067] Here, the remaining amount information signal Rs corresponding to the information on the remaining amount of recording paper P contained in the roll R may be an absolute value of the remaining amount of recording paper P contained in the roll R calculated based on the movement amounts dtx and dty, or may be information indicating that the remaining amount of recording paper P contained in the roll R stored in the medium storage unit 30 is sufficient, obtained by comparing the movement amounts dtx and dty with a predetermined threshold, information indicating that the remaining amount of recording paper P contained in the roll R stored in the medium storage unit 30 is low, or information indicating that the recording paper P contained in the roll R stored in the medium storage unit 30 has run out. The remaining amount information signal Rs may also be information that combines some of these pieces of information. The determination circuit 175 may determine the remaining amount of recording paper P contained in the roll R based on both the movement amounts dtx and dty and generate the remaining amount information signal Rs corresponding to the determination result, or may determine the remaining amount of recording paper P contained in the roll R based on only one of the movement amounts dtx and dty and generate the remaining amount information signal Rs corresponding to the determination result.

[0068] Here, the relationship between the movement amounts dtx and dty output by the medium remaining amount sensor 20 and the remaining amount of recording paper P contained in the roll R stored in the medium storage unit 30 will be described. FIG. 7 is a diagram for explaining the relationship between the movement amounts dtx and dty and the remaining amount of recording paper P. FIG. 7 shows an example of the movement amounts dtx and dty output by the medium remaining amount sensor 20 when the roll R is stored in the medium storage unit 30 at each of the storage positions r1, r2, r3, and r4 shown in FIG. 3. Here, FIG. 7 illustrates a case where the medium remaining amount sensor 20 is fixed to the printing device 1 or the main body case 2 so that the first axis x extends along the axis Y and the second axis y extends along the axis Z. Also, Figure 7 illustrates a case where the medium remaining amount sensor 20 irradiates laser light IL on the +X side of the side of the roll body R, on the -Y side of the central axis ax, near the boundary between the first recess and the second recess, and outputs the movement amounts dtx and dty of the roll body R on the +X side of the side of the roll body R, on the -Y side of the central axis ax, near the boundary between the first recess and the second recess.

[0069] As described above, the position of the roll R stored in the medium storage unit 30 changes depending on the remaining amount of recording paper P wound around the roll R. Specifically, when there is a large amount of recording paper P remaining around the roll R, for example, when an unused roll R is stored in the medium storage unit 30, the roll R is stored in the medium storage unit 30 at storage position r1. As the recording paper P wound around the roll R is subsequently pulled out, the remaining amount of recording paper P wound around the roll R decreases, and the diameter of the roll R decreases. As a result, the storage position of the roll R in the medium storage unit 30 changes in the order of storage position r2, storage position r3, and storage position r4. At this time, because the diameter of the roll R decreases, the rotational speed of the roll R changes as the recording paper P wound around the roll R is pulled out, and the movement direction Sr of the side of the roll R facing the remaining medium sensor 20 changes. Therefore, the values ​​of the movement amounts dtx and dty output by the remaining medium sensor 20 change.

[0070] This will be explained in detail using the example shown in Figure 7. When the roll R is stored at storage position r1 in the medium storage unit 30, the side of the roll R facing the medium remaining amount sensor 20 and the area of ​​the roll R irradiated with the laser light IL moves from the +Y side to the -Y side along the Y axis and from the -Z side to the +Z side along the Z axis as the recording paper P wound on the roll R is pulled out. At this time, the medium remaining amount sensor 20 outputs a movement amount dtx corresponding to the amount of movement along the Y axis from the +Y side to the -Y side of the area of ​​the roll R irradiated with the laser light IL, and a movement amount dty corresponding to the amount of movement along the Z axis from the -Z side to the +Z side of the area of ​​the roll R irradiated with the laser light IL.

[0071] When the roll R is stored at storage position r2 in the medium storage unit 30, the side of the roll R facing the remaining medium sensor 20, and the area of ​​the roll R that is irradiated with the laser light IL, moves from the +Y side to the -Y side along the Y axis as the recording paper P wound around the roll R is pulled out, and also moves from the -Z side to the +Z side along the Z axis. At this time, as the remaining amount of recording paper P wound around the roll R decreases, the diameter of the roll R becomes smaller. Therefore, the amount of movement along the Y axis from the +Y side to the -Y side of the area of ​​the roll body R irradiated with the laser light IL is smaller than the amount of movement along the Y axis from the +Y side to the -Y side of the area of ​​the roll body R irradiated with the laser light IL when the roll body R is stored in storage position r1, and the amount of movement along the Z axis from the -Z side to the +Z side of the area of ​​the roll body R irradiated with the laser light IL is greater than the amount of movement along the Z axis from the -Z side to the +Z side of the area of ​​the roll body R irradiated with the laser light IL when the roll body R is stored in storage position r1. Therefore, when the roll R is stored in storage position r2, the movement amount dtx output by the media remaining amount sensor 20 is smaller than the movement amount dtx output by the media remaining amount sensor 20 when the roll R is stored in storage position r1, and when the roll R is stored in storage position r2, the movement amount dty output by the media remaining amount sensor 20 is greater than the movement amount dty output by the media remaining amount sensor 20 when the roll R is stored in storage position r1.

[0072] Furthermore, when the roll R is stored at storage position r3 in the medium storage unit 30, the side of the roll R facing the remaining medium sensor 20, and the area of ​​the roll R that is irradiated with the laser light IL, moves from the +Y side to the -Y side along the Y axis as the recording paper P wound around the roll R is pulled out, and also moves from the -Z side to the +Z side along the Z axis. At this time, as the remaining amount of recording paper P wound around the roll R decreases, the diameter of the roll R becomes smaller. Therefore, the amount of movement along the Y axis from the +Y side to the -Y side of the area of ​​the roll body R irradiated with the laser light IL is smaller than the amount of movement along the Y axis from the +Y side to the -Y side of the area of ​​the roll body R irradiated with the laser light IL when the roll body R is stored in storage position r2, and the amount of movement along the Z axis from the -Z side to the +Z side of the area of ​​the roll body R irradiated with the laser light IL is greater than the amount of movement along the Z axis from the -Z side to the +Z side of the area of ​​the roll body R irradiated with the laser light IL when the roll body R is stored in storage position r2. Therefore, when the roll R is stored in storage position r3, the movement amount dtx output by the media remaining amount sensor 20 is smaller than the movement amount dtx output by the media remaining amount sensor 20 when the roll R is stored in storage position r2, and when the roll R is stored in storage position r3, the movement amount dty output by the media remaining amount sensor 20 is greater than the movement amount dty output by the media remaining amount sensor 20 when the roll R is stored in storage position r2.

[0073] Furthermore, when the roll R is stored in the medium storage unit 30 at storage position r4, the side of the roll R facing the remaining medium sensor 20, and the area of ​​the roll R that is irradiated with the laser light IL, moves from the +Y side to the -Y side along the Y axis as the recording paper P wound around the roll R is pulled out, and also moves from the -Z side to the +Z side along the Z axis. At this time, as the remaining amount of recording paper P wound around the roll R decreases, the diameter of the roll R becomes smaller. Therefore, the amount of movement along the Y axis of the area of ​​the roll body R irradiated with the laser light IL from the +Y side to the -Y side is smaller than the amount of movement along the Y axis of the area of ​​the roll body R irradiated with the laser light IL from the +Y side to the -Y side when the roll body R is stored in storage position r3, and the amount of movement along the Z axis of the area of ​​the roll body R irradiated with the laser light IL from the -Z side to the +Z side is greater than the amount of movement along the Z axis of the area of ​​the roll body R irradiated with the laser light IL from the -Z side to the +Z side when the roll body R is stored in storage position r3. Therefore, when the roll R is stored in storage position r4, the movement amount dtx output by the media remaining amount sensor 20 is smaller than the movement amount dtx output by the media remaining amount sensor 20 when the roll R is stored in storage position r3, and when the roll R is stored in storage position r4, the movement amount dty output by the media remaining amount sensor 20 is greater than the movement amount dty output by the media remaining amount sensor 20 when the roll R is stored in storage position r3.

[0074] As described above, the movement amount dtx output by the medium remaining amount sensor 20 gradually decreases as the diameter of the roll R stored in the medium storage unit 30 decreases, and the movement amount dty output by the medium remaining amount sensor 20 gradually increases as the diameter of the roll R stored in the medium storage unit 30 decreases. In other words, the movement amount dtx output by the medium remaining amount sensor 20 is correlated with the remaining amount of recording paper P wound around the roll R stored in the medium storage unit 30, and in the example shown in FIG. 7, it continuously decreases as the remaining amount of recording paper P wound around the roll R decreases, and the movement amount dty output by the medium remaining amount sensor 20 is correlated with the remaining amount of recording paper P wound around the roll R stored in the medium storage unit 30, and in the example shown in FIG. 7, it continuously increases as the remaining amount of recording paper P wound around the roll R decreases.

[0075] The determination circuit 175 acquires at least one of the movement amounts dtx and dty, which change continuously as the remaining amount of recording paper P wound around the roll R stored in the medium storage unit 30 decreases. The determination circuit 175 calculates the remaining amount of recording paper P wound around the roll R stored in the medium storage unit 30 by substituting the acquired information on the movement amounts dtx and dty into a predetermined calculation formula or converting it using a predetermined table. The determination circuit 175 then outputs the calculation result as a remaining amount information signal Rs.

[0076] The determination circuit 175 may also compare the movement amount dtx, which decreases continuously as the remaining amount of recording paper P wound around the roll R stored in the medium storage unit 30 decreases, with a predetermined threshold value. If the movement amount dtx is greater than a predetermined first threshold, the judgment circuit 175 determines that the remaining amount of recording paper P contained in the roll R stored in the medium storage unit 30 is sufficient, and outputs a remaining amount information signal Rs indicating that the remaining amount of recording paper P contained in the roll R stored in the medium storage unit 30 is sufficient; if the movement amount dtx is smaller than the predetermined first threshold and greater than a predetermined second threshold, the judgment circuit 175 determines that the remaining amount of recording paper P contained in the roll R stored in the medium storage unit 30 is low, and outputs a remaining amount information signal Rs including near-end information indicating that the remaining amount of recording paper P contained in the roll R stored in the medium storage unit 30 is low; if the movement amount dtx is smaller than the predetermined second threshold, the judgment circuit 175 determines that the recording paper P contained in the roll R stored in the medium storage unit 30 is about to run out, and outputs a remaining amount information signal Rs including end information indicating that the recording paper P contained in the roll R stored in the medium storage unit 30 has run out. That is, the determination circuit 175 may determine the remaining amount of recording paper P contained in the roll R based on the first threshold value and the second threshold value.

[0077] The determination circuit 175 may also compare the movement amount dty, which increases continuously as the remaining amount of recording paper P wound around the roll R stored in the medium storage unit 30 decreases, with a predetermined threshold value. If the movement amount dty is smaller than a predetermined third threshold, the judgment circuit 175 determines that the remaining amount of recording paper P contained in the roll R stored in the medium storage section 30 is sufficient, and outputs a remaining amount information signal Rs indicating that the remaining amount of recording paper P contained in the roll R stored in the medium storage section 30 is sufficient; if the movement amount dty is greater than the predetermined third threshold and less than a predetermined fourth threshold, the judgment circuit 175 determines that the remaining amount of recording paper P contained in the roll R stored in the medium storage section 30 is low, and outputs a remaining amount information signal Rs including near-end information indicating that the remaining amount of recording paper P contained in the roll R stored in the medium storage section 30 is low; if the movement amount dty is greater than the predetermined fourth threshold, the judgment circuit 175 determines that the recording paper P contained in the roll R stored in the medium storage section 30 is about to run out, and outputs a remaining amount information signal Rs including end information indicating that the recording paper P contained in the roll R stored in the medium storage section 30 has run out. That is, the determination circuit 175 may determine the remaining amount of recording paper P contained in the roll R based on the third threshold value and the fourth threshold value.

[0078] Here, the relationship between changes in the movement amounts dtx and dty output by the media remaining amount sensor 20 and the remaining amount of recording paper P wound around the roll R is not limited to the example shown in Figure 7, and changes depending on the fixed position and angle of the media remaining amount sensor 20. However, regardless of the fixed position and angle of the media remaining amount sensor 20 to the printing device 1 and the main body case 2, the movement amount dtx output by the media remaining amount sensor 20 changes continuously as the remaining amount of recording paper P wound around the roll R decreases, and the movement amount dty output by the media remaining amount sensor 20 changes continuously as the remaining amount of recording paper P wound around the roll R decreases. There is a correlation between these continuously changing movement amounts dtx and dty output by the media remaining amount sensor 20 and the remaining amount of recording paper P wound around the roll R, regardless of the fixed position and angle of the media remaining amount sensor 20 to the printing device 1 and the main body case 2.

[0079] Therefore, by using at least one of an appropriate calculation formula, table, and threshold value according to the fixed position and fixed angle of the media remaining amount sensor 20, the judgment circuit 175 can determine the remaining amount of the roll R, that is, the remaining amount of recording paper P wound around the roll R, even if the media remaining amount sensor 20 is fixed at different positions and angles on the printing device 1 and the main body case 2.

[0080] Here, it is preferable that the medium remaining amount sensor 20 does not include a lens in the optical path of the laser light IL output by the light-emitting element 21, which is the optical path of the laser light IL that is irradiated onto the side surface of the roll R. Furthermore, if the medium remaining amount sensor 20 includes a lens in the optical path of the laser light IL output by the light-emitting element 21, which is the optical path of the laser light IL that is irradiated onto the side surface of the roll R, it is preferable that a lens with a deep depth of field is used. This makes it possible to widen the range of the focus of the laser light IL output by the light-emitting element 21, and to obtain the movement amounts dtx and dty even if the roll R stored in the medium storage unit 30 moves in the direction along the X-axis due to vibration or the like.

[0081] 4.Fixed position of media remaining sensor A printer 1 employing the throw-in method as shown in this embodiment has the advantage that the user can easily load the roll R into the printer 1. However, in a printer 1 employing the throw-in method, the position of the roll R changes as recording paper P is pulled from the roll R. Therefore, depending on the fixed position of the media remaining sensor 20, there may be periods when the laser light IL output by the media remaining sensor 20 does not properly illuminate the side of the roll R. As a result, the accuracy with which the media remaining sensor 20 detects the amount of movement of the side of the roll R may decrease, and the accuracy of the movement amounts dtx and dty output by the media remaining sensor 20 may decrease. Furthermore, if the accuracy of the movement amounts dtx and dty output by the media remaining sensor 20 decreases, the accuracy with which the determination circuit 175 determines the remaining amount of recording paper P wound around the roll R decreases. Therefore, in a printing device 1 that employs the throw-in method, fixing the media remaining sensor 20 in an appropriate position is important from the standpoint of accurately determining the remaining amount of recording paper P wound around the roll R stored in the media storage section 30, and below we will explain an example of the optimal fixing position for the media remaining sensor 20 in the printing device 1.

[0082] To reduce the risk of a decrease in the accuracy of the movement amounts dtx and dty, the medium remaining sensor 20 needs to be fixed in a position where it can always irradiate the laser light IL onto the side of the roll R, even if the position of the roll R changes as recording paper P is pulled out from the roll R. To achieve such a fixed position for the medium remaining sensor 20, the following three conditions must be met. The first condition is that the media remaining sensor 20 is fixed in a position where at least a portion of the laser light IL output by the media remaining sensor 20 can be irradiated onto the side of an unused roll R when the roll R has the most recording paper P wound around it; the second condition is that the media remaining sensor 20 is fixed in a position where at least a portion of the laser light IL output by the media remaining sensor 20 can be irradiated onto the side of an unused roll R when the roll R has the least amount of recording paper P wound around it, for example, when the roll R includes a core material C, the media remaining sensor 20 is fixed in a position where the irradiation circle of the laser light IL output by the media remaining sensor 20 does not include all of the path of movement of the cavity H, which changes position along with the roll R as the recording paper P is pulled out from the roll R.

[0083] Specific examples of the first, second, and third conditions will be described below.

[0084] First, the fixed position of the medium remaining amount sensor 20 that satisfies the first condition will be described. Fig. 8 is a diagram for explaining the fixed position of the medium remaining amount sensor 20 that satisfies the first condition. Here, the diameter Ld shown in Fig. 8 is the diameter of the irradiation circle when the laser light IL output by the medium remaining amount sensor 20 is irradiated onto the side surface of the roll body R.

[0085] As shown in FIG. 8, when an unused roll R is stored in the medium storage unit 30, the roll R is supported by support members 32 and 33. FIG. 8 also illustrates an irradiation area IRa. The irradiation area IRa is a substantially circular area having a center at the center of the unused roll R stored in the medium storage unit 30 and a radius larger than the radius of the roll R by a diameter Ld, excluding a substantially circular area having a center at the center of a cavity H in a core material C of the unused roll R stored in the medium storage unit 30 and a radius smaller than the radius of the cavity H by a diameter Ld. The medium remaining amount sensor 20 is fixed so that the entire irradiation circle formed when the laser light IL output by the medium remaining amount sensor 20 is irradiated onto the side surface of the roll R is included in the irradiation area IRa. This allows at least a portion of the laser light IL output by the medium remaining amount sensor 20 to be irradiated onto the side surface of the unused roll R stored in the medium storage unit 30. In other words, the first condition is satisfied.

[0086] Next, a fixed position of the medium remaining amount sensor 20 that satisfies the second condition will be described. Fig. 9 is a diagram for explaining a fixed position of the medium remaining amount sensor 20 that satisfies the second condition. Here, the diameter Ld shown in Fig. 9 is the diameter of the irradiation circle when the laser light IL output by the medium remaining amount sensor 20 is irradiated onto the side surface of the roll body R, similar to Fig. 8.

[0087] When a roll R containing no recording paper P and made only of a core material C is housed in the medium storage unit 30, the diameter of the core material C is smaller than the distance between the +Y end of the support member 32 and the −Y end of the support member 33. Therefore, the roll R containing only the core material C is supported by the second recess formed by the support members 31, 34, and 35 in a state where it can move along the Y axis. Therefore, even when the core material C is located at the +Y end of the second recess and is housed in the medium storage unit 30 in contact with the support member 34, at least a portion of the output laser light IL can be irradiated onto the side surface of the roll R containing only the core material C. Furthermore, even when the core material C is located at the −Y end of the second recess and is housed in the medium storage unit 30 in contact with the support member 35, the second condition is satisfied by fixing the medium remaining amount sensor 20 to a position where at least a portion of the output laser light IL can be irradiated onto the side surface of the roll R containing only the core material C.

[0088] First, using FIG. 9(a), a case will be described in which a roll R containing no recording paper P and made only of a core material C is housed in the medium storage unit 30 while in contact with the support member 34. As shown in FIG. 9(a), when a roll R containing no recording paper P and made only of a core material C is housed in the medium storage unit 30 while in contact with the support member 34, the roll R is supported by the support members 31 and 34. FIG. 9(a) also illustrates an irradiation area IRb1. The irradiation area IRb1 is a substantially circular area having its center at the center of the roll R containing only the core material C housed in the medium storage unit 30 while in contact with the support member 34 and having a radius larger than the radius of the roll R by a diameter Ld, excluding a substantially circular area having its center at the center of a cavity H of the core material C of the roll R containing only the core material C housed in the medium storage unit 30 while in contact with the support member 34 and having a radius smaller than the radius of the cavity H by a diameter Ld. The medium remaining amount sensor 20 is fixed so that the entire irradiation circle when the laser light IL output by the medium remaining amount sensor 20 is irradiated onto the side of the roll body R is included in the irradiation area IRb1, and at least a portion of the laser light IL output by the medium remaining amount sensor 20 is irradiated onto the side of the roll body R, which is composed only of the core material C contained in the medium storage section 30 while in contact with the support member 34.

[0089] Next, using FIG. 9(b), a case will be described in which a roll R containing no recording paper P and made only of a core material C is housed in the medium storage unit 30 while in contact with the support member 35. As shown in FIG. 9(b), when a roll R containing no recording paper P and made only of a core material C is housed in the medium storage unit 30 while in contact with the support member 35, the roll R is supported by the support members 31 and 35. FIG. 9(b) also illustrates an irradiation area IRb2. The irradiation area IRb2 is a substantially circular area having a center at the center of the roll R containing only the core material C housed in the medium storage unit 30 while in contact with the support member 35 and a radius larger than the radius of the roll R by a diameter Ld, excluding a substantially circular area having a center at the center of a cavity H of the core material C of the roll R containing only the core material C housed in the medium storage unit 30 while in contact with the support member 35 and a radius smaller than the radius of the cavity H by a diameter Ld. The medium remaining amount sensor 20 is fixed so that the entire irradiation circle formed when the laser light IL output by the medium remaining amount sensor 20 is irradiated onto the side of the roll body R is included in the irradiation area IRb2, and at least a portion of the laser light IL output by the medium remaining amount sensor 20 is irradiated onto the side of the roll body R, which is composed only of the core material C contained in the medium storage section 30 while in contact with the support member 35.

[0090] 9(c), the medium remaining amount sensor 20 is fixed so that the entire irradiation circle when the laser light IL output by the medium remaining amount sensor 20 is irradiated onto the side surface of the roll R is included in the irradiation area IRb where the irradiation areas IRb1 and IRb2 overlap, and at least a portion of the laser light IL output by the medium remaining amount sensor 20 is irradiated onto the side surface of the roll R which does not contain the recording paper P contained in the medium storage section 30 and is made up of only the core material C. In other words, the second condition is met.

[0091] Next, a fixed position of the medium remaining sensor 20 that satisfies the third condition will be described. FIG. 10 is a diagram illustrating a fixed position of the medium remaining sensor 20 that satisfies the third condition. In FIG. 10, the position of the roll R when an unused roll R is stored in the medium storage unit 30 is illustrated as storage position rf, and the position of the cavity H at this time is illustrated as cavity position hf. Also, the position of the roll R when a roll R that does not contain recording paper P and is composed only of a core material C is illustrated as storage position re, and the position of the cavity H at this time is illustrated as cavity position he. Similarly to FIGS. 8 and 9, the diameter Ld shown in FIG. 10 is the diameter of the irradiation circle when the laser light IL output by the medium remaining sensor 20 is irradiated onto the side surface of the roll R.

[0092] The diameter of the roll R stored in the medium storage unit 30 decreases as the recording paper P is pulled out. As a result, the roll R stored in the medium storage unit 30 moves from storage position rf to storage position re, and as the roll R moves, the cavity H moves from cavity position hf to cavity position he. At this time, the center positions of the roll R and the cavity H move from the +Z side to the -Z side along the central axis ax, as described above. Figure 10 shows the trajectory of the movement of the cavity H at this time, the trajectory of the cavity H as it moves from cavity position hf to cavity position he, as cavity trajectory TH.

[0093] FIG. 10 also illustrates a non-irradiated region nIR. The non-irradiated region nIR is an area inside the cavity locus TH, with its +Y end positioned a distance Ld to the -Y side from the +Y end of the cavity locus TH, its -Y end positioned a distance Ld to the +Y side from the -Y end of the cavity locus TH, its +Z end positioned a distance Ld to the -Z side from the +Z end of the cavity locus TH, and its -Z end positioned a distance Ld to the +Z side from the -Z end of the cavity locus TH. The medium remaining sensor 20 is fixed so that the entire irradiation circle formed when the output laser light IL is irradiated onto the side surface of the roll R is not included in the non-irradiated region nIR. As a result, the laser light IL output by the medium remaining sensor 20 is not included within the cavity locus TH, which is the path along which the cavity H, whose position changes along with the roll R as the recording paper P is pulled out from the roll R, moves. In other words, the third condition is met.

[0094] The area where the irradiation area IRa based on the first condition and the irradiation area IRb based on the second condition overlap, minus the non-irradiation area nIR based on the third condition, corresponds to the irradiation area IR shown in Fig. 11. In other words, the irradiation area IR is an area that satisfies all of the above-mentioned first condition, second condition, and third condition.

[0095] 11 is a diagram showing an example of an irradiation area IR. By fixing the medium remaining amount sensor 20 so that the entire irradiation circle formed by the laser light IL output by the medium remaining amount sensor 20 is included in the side of the roll R located in this irradiation area IR, the laser light IL output by the medium remaining amount sensor 20 is always irradiated onto the side of the roll R, even if the position of the roll R changes. In other words, the medium remaining amount sensor 20 is positioned so that at least a portion of the emitted light can irradiate the side of the roll R, and at least one of the recording paper P and the core C, at any time during which the center position of the roll R changes as recording paper P is pulled out from the roll R. This reduces the risk of a decrease in the accuracy of the movement amounts dtx and dty output by the medium remaining amount sensor 20, and also reduces the risk of a decrease in the accuracy of the determination circuit 175's determination of the remaining amount of recording paper P wound around the roll R.

[0096] Here, the axis along which the cavity H of the core material C extends is an example of a rotation axis, the side of the roll body R is an example of a detection surface, the laser light IL is an example of light irradiated onto the detection surface, the reflected light RL is an example of reflected light, the media remaining amount sensor 20 is an example of an optical tracking sensor, the direction along the first axis x is an example of a first direction, the direction along the second axis y is an example of a second direction, the support member 32 is an example of a first support part, the support member 33 is an example of a second support part, the support member 31 is an example of a third support part, one of the first threshold and the second threshold is an example of a first judgment threshold, the other of the first threshold and the second threshold is an example of a second judgment threshold, one of the third threshold and the fourth threshold is another example of a first judgment threshold, and the other of the third threshold and the fourth threshold is another example of a second judgment threshold.

[0097] 5. Effects The printing device 1 of this embodiment, configured as described above, has a medium storage section 30 that stores the roll R so that the center position of the roll R changes as the recording paper P is pulled out from the roll R, and a remaining amount detection circuit 170 that detects the remaining amount of recording paper P stored in the medium storage section 30.The remaining amount detection circuit 170 has a medium remaining amount sensor 20 that shines light onto the side of the roll R that intersects with the rotation axis of the roll R and tracks the movement of the roll R that rotates and moves as the recording paper P is pulled out based on the reflected light RL, and outputs the tracking result, and a judgment circuit 175 that judges the remaining amount of recording paper P based on the detection result of the medium remaining amount sensor 20.

[0098] In this type of printing device 1, when recording paper P is pulled out from the roll R, the diameter of the roll R changes as the recording paper P is pulled out, and the trajectory of the roll R's rotational movement as the recording paper P is pulled out changes in response to the change in the diameter of the roll R. That is, the trajectory of the roll R's movement detected and output by the media remaining sensor 20 changes in response to the remaining amount of recording paper P wound around the roll R. The determination circuit 175 determines the remaining amount of recording paper P based on the trajectory of the roll R's movement, which is the detection result of the media remaining sensor 20 and changes in response to the remaining amount of recording paper P wound around the roll R. That is, the printing device 1 of this embodiment determines the remaining amount of recording paper P wound around the roll R stored in the medium storage unit 30 in response to the trajectory of the roll R's movement as the recording paper P is pulled out. Therefore, even in a printing device 1 that employs a throwing method in which the roll R stored in the medium storage unit 30 is not fixed to a paper tube or the like, the remaining amount of recording paper P stored in the medium storage unit 30 can be determined.

[0099] In this case, in the printing device 1, the medium remaining amount sensor 20 included in the remaining amount detection circuit 170 detects the amount of movement dtx of the roll R in a direction along a first axis x that intersects the rotation axis and the amount of movement dty of the roll R in a direction along a second axis y that intersects the rotation axis and is perpendicular to the direction along the first axis x, and the determination circuit 175 may use at least one of the movement amounts dtx and dty to determine the remaining amount of recording paper P wound around the roll R stored in the medium storage unit 30. Even with this remaining amount detection circuit 170, the remaining amount of recording paper P wound around the roll R stored in the medium storage unit 30 can be determined based on the movement amounts dtx and dty corresponding to the trajectory of the roll R that moves as the recording paper P is pulled out. Therefore, even in a printing device 1 that employs a throwing method in which the roll R stored in the medium storage unit 30 is not fixed to a paper tube or the like, the remaining amount of recording paper P stored in the medium storage unit 30 can be determined.

[0100] Furthermore, in the printing device 1 of this embodiment, the media remaining amount sensor 20 included in the remaining amount detection circuit 170 detects speckles contained in the image corresponding to the reflected light RL, and by tracking the movement of the side of the roll R based on the detection results, it becomes possible to accurately acquire the feature points SPa and SPb contained in the reflected light RL acquired by the media remaining amount sensor 20. This improves the accuracy with which the media remaining amount sensor 20 detects the trajectory of movement of the roll R as the recording paper P is drawn out, and also improves the accuracy with which the judgment circuit 175 judges the remaining amount of recording paper P.

[0101] In the printing device 1 of this embodiment, the laser light IL output by the medium remaining amount sensor 20 included in the remaining amount detection circuit 170 is irradiated onto the recording paper P or the core C around which the recording paper P is wound, on the side of the roll R. Because the recording paper P is wound around the core C, it rotates as the recording paper P is pulled out from the roll R. Therefore, the medium remaining amount sensor 20 included in the remaining amount detection circuit 170 detects the trajectory of movement of at least one of the recording paper P on the roll R or the core C around which the recording paper P is wound, which moves as the recording paper P is pulled out, and the determination circuit 175 can determine the remaining amount of recording paper P.

[0102] At this time, the medium remaining amount sensor 20 included in the remaining amount detection circuit 170 is positioned so that at least a portion of the emitted light can irradiate at least one of the recording paper P and the core C, regardless of the period during which the center position of the roll R changes as the recording paper P is pulled out from the roll R. This allows the medium remaining amount sensor 20 included in the remaining amount detection circuit 170 to continuously detect the trajectory of the movement of the roll R as the recording paper P is pulled out, and the determination circuit 175 to continuously determine the remaining amount of recording paper P. In other words, the accuracy of detection and determination of the remaining amount of recording paper P in the remaining amount detection circuit 170 is improved.

[0103] In addition, the judgment circuit 175 determines the remaining amount of recording paper P from the movement amount dtx corresponding to the trajectory of the roll R that moves as the recording paper P is pulled out, based on the first threshold value and the second threshold value, and determines the remaining amount of recording paper P from the movement amount dty corresponding to the trajectory of the roll R that moves as the recording paper P is pulled out, based on the third threshold value and the fourth threshold value.In this way, the judgment circuit 175 can detect not only information on whether or not there is recording paper P wound around the roll R as the remaining amount of recording paper P wound around the roll R stored in the medium storage section 30, but also information on whether there is a sufficient amount of recording paper P wound around the roll R, or whether there is only a small amount of recording paper P wound around the roll R.

[0104] Furthermore, by not positioning a lens in the optical path of the laser light IL that the medium remaining amount sensor 20 irradiates onto the side surface of the roll R, it is possible to widen the range of focal lengths of the laser light IL that irradiates onto the side surface of the roll R. This makes it possible to determine the remaining amount of recording paper P even if there is variation in the position of the roll R stored in the medium storage unit 30 because the printing device 1 uses a throwing method.

[0105] Although the embodiments and modifications have been described above, the present invention is not limited to these embodiments and can be embodied in various forms without departing from the spirit of the present invention. For example, the above embodiments can be combined as appropriate.

[0106] The present invention includes configurations that are substantially the same as the configurations described in the embodiments (for example, configurations with the same functions, methods, and results, or configurations with the same purpose and effects). The present invention also includes configurations in which non-essential parts of the configurations described in the embodiments are replaced. The present invention also includes configurations that achieve the same effects or purposes as the configurations described in the embodiments. The present invention also includes configurations in which publicly known technology is added to the configurations described in the embodiments.

[0107] The following can be derived from the above-described embodiment.

[0108] One aspect of the printing device is a medium storage section that stores a roll of recording paper; a print head that prints on the recording paper pulled out from the roll by rotation; a remaining amount detection circuit for detecting the remaining amount of the recording paper accommodated in the medium accommodation unit; Equipped with the medium storage unit stores the roll body so that the center position of the roll body changes as the recording paper is pulled out from the roll body, The remaining amount detection circuit an optical tracking sensor that irradiates light onto a detection surface of the roll body that intersects with the rotation axis of the roll body and detects reflected light; a determination circuit that determines the remaining amount of the recording paper based on the detection result of the optical tracking sensor; It has.

[0109] With this printing device, an optical tracking sensor detects the trajectory of the roll's movement, which changes depending on the amount of recording paper remaining in the roll, and a determination circuit determines the remaining amount of recording paper based on the detection results of the optical tracking sensor, which is the trajectory of the roll's movement, which changes depending on the amount of recording paper remaining in the roll. This makes it possible to determine the remaining amount of recording paper contained in the medium storage unit even in printing devices that use a throw-in method in which the roll stored in the medium storage unit is not fixed to a paper tube or the like.

[0110] In one aspect of the printing device, The optical tracking sensor may detect speckles in the reflected light.

[0111] According to this printing device, the optical tracking sensor detects speckles contained in the reflected light and tracks the movement of the side of the roll body based on the detection results, thereby improving the accuracy with which the optical tracking sensor detects the trajectory of the movement of the roll body.

[0112] In one aspect of the printing device, The determination circuit may determine the remaining amount of recording paper based on at least one of the amount of movement of the roll body in a first direction that intersects with the rotation axis and the amount of movement of the roll body in a second direction that intersects with the rotation axis and is perpendicular to the first direction.

[0113] According to this printing device, the remaining amount of recording paper contained in the roll body stored in the medium storage section can be determined based on the trajectory of the roll body that moves as the recording paper is pulled out, and the amount of movement of the roll body in the first direction and the amount of movement of the roll body in the second direction.Therefore, even in a printing device that uses a throw-in method in which the roll body stored in the medium storage section is not fixed to a paper tube or the like, the remaining amount of recording paper stored in the medium storage section can be determined.

[0114] In one aspect of the printing device, the medium container has a first support portion, a second support portion, and a third support portion; When the diameter of the roll body is larger than a predetermined value, the roll body is supported by the first support portion and the second support portion, and does not contact the third support portion; When the diameter of the roll body is smaller than the predetermined value, the roll body may be supported by the third support portion.

[0115] In one aspect of the printing device, the roll body includes a core material around which the recording paper is wound, The optical tracking sensor may be positioned in a position where it can irradiate at least one of the recording paper and the core material during any period in which the center position of the roll body changes as the recording paper is pulled out from the roll body.

[0116] According to this printing device, even if the center position of the roll body changes as the recording paper is pulled out from the roll body, the optical tracking sensor possessed by the remaining amount detection circuit can continuously detect the trajectory of the movement of the roll body R as the recording paper moves as it is pulled out, and the judgment circuit can continuously judge the remaining amount of recording paper.

[0117] In one aspect of the printing device, The determination circuit may determine the remaining amount of recording paper based on a first determination threshold and a second determination threshold.

[0118] According to this printing device, the judgment circuit can detect the remaining amount of recording paper contained in the roll stored in the media storage section, including whether or not there is recording paper in the roll, whether the remaining amount of recording paper in the roll is sufficient, or whether there is only a small amount of recording paper remaining in the roll.

[0119] In one aspect of the printing device, The optical tracking sensor may not have a lens in the optical path of the light irradiated onto the detection surface.

[0120] This printing device makes it possible to widen the range of focal lengths of the laser light irradiated onto the side of the roll body, making it possible to determine the remaining amount of recording paper even if there is variation in the position of the roll body stored in the media storage section. [Explanation of symbols]

[0121] 1...printing device, 2...main body case, 3...opening / closing door, 4...discharge outlet, 5...notification unit, 6...power switch, 7...opening / closing lever, 8...hinge unit, 12...transport roller, 14a...movable blade, 14b...fixed blade, 15...paper detection sensor, 16...encoder, 17...disk, 18...photosensor, 19...opening / closing sensor, 20...remaining media sensor, 21...light-emitting element, 22...light-receiving unit, 23...DSP, 24...receiving Optical element, 30...medium storage section, 31-35...support members, 100...main control circuit, 110...power input IF, 120...power generation circuit, 150...printing section, 160...external IF, 170...remaining amount detection circuit, 175...determination circuit, 200...print head, 210...heating element, 220...head control circuit, 230...conveyance control circuit, 240...cutting control circuit, C...core material, H...cavity, P...recording paper, R...roll body

Claims

1. a medium storage section that stores a roll of recording paper; a print head that prints on the recording paper pulled out from the roll by rotation; a remaining amount detection circuit for detecting the remaining amount of the recording paper accommodated in the medium accommodation unit; Equipped with the medium storage unit stores the roll body so that the center position of the roll body changes as the recording paper is pulled out from the roll body, The remaining amount detection circuit an optical tracking sensor that irradiates light onto a detection surface of the roll body that intersects with the rotation axis of the roll body and detects reflected light; a determination circuit that determines the remaining amount of the recording paper based on the detection result of the optical tracking sensor; having A printing device characterized by:

2. the optical tracking sensor detects speckles in the reflected light.

2. The printing device according to claim 1.

3. the determination circuit determines the remaining amount of recording paper based on at least one of the amount of movement of the roll body in a first direction intersecting the rotation axis and the amount of movement of the roll body in a second direction intersecting the rotation axis and orthogonal to the first direction.

2. The printing device according to claim 1.

4. the medium container has a first support portion, a second support portion, and a third support portion; When the diameter of the roll body is larger than a predetermined value, the roll body is supported by the first support portion and the second support portion, and does not contact the third support portion; When the diameter of the roll body is smaller than the predetermined value, the roll body is supported by the third support portion.

2. The printing device according to claim 1.

5. the roll body includes a core material around which the recording paper is wound, the optical tracking sensor is disposed at a position where it can irradiate at least one of the recording paper and the core material at any time during which the center position of the roll body changes as the recording paper is pulled out from the roll body; 2. The printing device according to claim 1.

6. the determination circuit determines the remaining amount of recording paper based on a first determination threshold and a second determination threshold; 2. The printing device according to claim 1.

7. the optical tracking sensor does not have a lens in the optical path of light irradiated onto the detection surface; 2. The printing device according to claim 1.

Images