Printer, density setting device, and program

Abstract

The objective is to provide a printer, a density setting device, and a program capable of automatically identifying the loaded paper into a density setting group corresponding to that paper. [Solution] The system comprises a printing means for printing on a medium (e.g., paper), a light sensor for receiving reflected light of a predetermined light irradiated onto the medium before printing, and a density setting means for setting print density for groups corresponding to the type of medium based on an output value output by the light sensor upon receiving the reflected light.

Description

Technical Field

[0001] Embodiments of the present invention relate to a printer, a density setting device, and a program.

Background Art

[0002] Conventionally, when a user adjusts the printing density set in a printer, it is performed by setting buttons provided on the printer.

[0003] Note that in a thermal printer, when replacing thermal paper, a pattern in which the recording density is changed stepwise is recorded on the thermal paper, and energy applied to the thermal head is determined based on an output signal output when the recorded pattern is read by a sensor (see Patent Document 1).

[0004] However, conventionally, for papers that are adjusted to an optimal density by automatic density setting, they are papers of a predetermined group with similar color development characteristics on the printing surface of the paper. When papers of a different group with different color development characteristics on the printing surface are used, the density adjustment is not optimal. Therefore, when using papers of a different group, the user has to manually adjust the density by operating the setting buttons, which is time-consuming and laborious.

Summary of the Invention

Problems to be Solved by the Invention

[0005] The problem to be solved by the present invention is to provide a printer, a density setting device, and a program capable of automatically discriminating a set paper into a group of density settings corresponding to the paper.

Means for Solving the Problems

[0006] The printer of this embodiment includes printing means for printing on a medium, a light sensor for receiving reflected light of a predetermined light irradiated onto the medium before printing, and density setting means for setting print density for groups corresponding to the type of medium based on an output value output by the light sensor upon receiving the reflected light. [Brief explanation of the drawing]

[0007] [Figure 1] Figure 1 is a perspective view showing an example of the appearance of a printer according to this embodiment. [Figure 2] Figure 2 shows an example of the internal device configuration of a printer. [Figure 3] Figure 3 shows an example of the configuration of a printer's control block. [Figure 4] Figure 4 shows an example of the data structure of a print density table. [Figure 5] Figure 5 is a flowchart showing an example of the print density setting operation performed by a printer. [Figure 6] Figure 6 is an explanatory diagram of the threshold determination in step S3. [Figure 7] Figure 7 shows an example of the internal device configuration of a printer according to a modified embodiment. [Figure 8] Figure 8 is a flowchart showing an example of the print density setting operation performed by the modified printer. [Figure 9] Figure 9 is an explanatory diagram for delta calculation and group discrimination. [Figure 10] Figure 10 shows an example of the configuration of a concentration setting device according to another embodiment. [Modes for carrying out the invention]

[0008] The embodiments will be described in detail below with reference to the drawings. The embodiments will be described below using a thermal printer as an example. However, the present invention is not limited to the embodiments described below.

[0009] The following example illustrates the configuration of a thermal printer used in a POS terminal. Because it is a thermal printer used in a POS terminal, it includes other components besides the printing means, the optical sensor used to identify paper groups, and the density setting means. The example below is an application to a direct thermal recording printer (also called a direct thermal printer) that uses a direct thermal recording method as the printing means. While roll paper is used as the paper, the paper is not limited to roll paper. Furthermore, other printable media may be used as well.

[0010] The printer according to this embodiment may be applied in any other form as appropriate, as long as it includes a printing means, an optical sensor used for identifying paper groups, and a density setting means.

[0011] Figure 1 is a perspective view showing an example of the external appearance of a printer according to the embodiment. Figure 2 is a diagram showing an example of the internal device configuration of the printer according to the embodiment. Note that the printer is a thermal printer as an example, and the internal device configuration is shown schematically for ease of understanding.

[0012] The X, Y, and Z axes shown in Figures 1 and 2 are coordinate axes. These should be referenced as appropriate when explaining direction.

[0013] First, let's describe the casing 10 of the printer 1 shown in Figure 1. The casing 10, as an example, has a first casing 11 and a second casing 12. The second casing 12 is rotatably supported relative to the first casing 11 via a shaft 14 (see Figure 2) located at one end. In this casing 10, the user replaces the roll paper 30 (see Figure 2) inside by opening and closing the second casing 12 relative to the first casing 11, using the end with the shaft 14 as a pivot point. The output port 13 provided on the top surface of the casing 10 is the output port for the paper 31 (see Figure 2) of the roll paper 30 (see Figure 2).

[0014] Next, while referring to FIG. 2, the internal device configuration of the printer 1 will be described. The printer 1 has a housing 10 with an accommodating portion 15, a platen roller 16, a thermal head 17, a cutter mechanism 18, etc. The printer 1 pulls out the paper 31 from the roll paper 30 accommodated in the accommodating portion 15 by the platen roller 16 etc., prints on the pulled-out paper 31 by the thermal head 17, and cuts and discharges it with the cutter mechanism 18.

[0015] The roll paper 30 is a roll portion of paper obtained by winding a long paper 31 around a roll core 32. Due to the printing method using the thermal head 17, the paper 31 is paper for forming characters and patterns by the reaction of heat. As an example, it is thermal paper etc.

[0016] The accommodating portion 15 is a space for accommodating the roll paper 30, and is a so-called throw-in type that does not pivotally support the roll core 32 of the roll paper 30. For this reason, the bottom surface portion where the accommodated roll paper 30 contacts has a rotating portion 60 for rotating the roll paper 30.

[0017] The rotating portion 60 is composed of a roller or a belt etc., and feeds the roll paper 30 in the feed direction for discharging the paper 31 to the discharge port 13 by rotating the roll paper 30 in the B direction in FIG. 2 by the rotating portion 60. When the roll paper 30 is rotated in the direction opposite to the B direction by the rotating portion 60, the paper 31 can be back-fed in the back-feed direction opposite to the feed direction.

[0018] In the case of the throw-in type as in this example, the printer 1 may have a member (also called a flapper) for pressing the roll paper 30 accommodated in the accommodating portion 15 from the upper (Z direction) side and pressing it against the inner wall of the accommodating portion 15. For example, the roll paper 30 is pressed in the direction of the bottom surface of the accommodating portion 15 by a biasing member such as a torsion spring.

[0019] Note that in FIG. 2, a configuration having a rotating portion 60 in the accommodating portion 15 is shown because the roll core 32 of the roll paper 30 is not supported. However, a configuration without the rotating portion 60 may also be used. By providing a bearing or the like in the accommodating portion 15, the roll core 32 of the roll paper 30 can be rotatably supported, and a configuration without the rotating portion 60 may also be used.

[0020] In the configuration of the printer 1 shown in FIG. 2, the thermal head 17 and the platen roller 16 correspond to the "printing means". The paper 31 is fed in the feed direction by controlling the rotation of the platen roller 16 and is printed by the thermal head 17. Further, the platen roller 16 can also rotate to return the paper 31 fed in the feed direction from the printing position in the backfeed direction.

[0021] A plurality of heating elements are aligned in the thermal head 17. The thermal head 17 prints on the paper 31 at the printing position sandwiched between the thermal head 17 and the platen roller 16 by the heating of the heating elements corresponding to the print data.

[0022] The thermal head 17 is configured, for example, on the side of the first housing 11, and the platen roller 16 is configured on the side of the second housing 12. In that case, by closing the second housing 12, the platen roller 16 abuts against the thermal head 17 and is in the arrangement shown in FIG. 2. The paper 31 is fed in the feed direction, passes through the printing position, and is discharged from the discharge port 13.

[0023] The cutter mechanism 18 is an example of a cutting means for cutting the paper 31. The cutter mechanism 18 has a first blade 41 and a second blade 42. Either the first blade 41 or the second blade 42 is a fixed blade, and the other is a movable blade. The first blade 41 and the second blade 42 are arranged to face each other across the conveyance path of the paper 31. The cutter mechanism 18 cuts the paper 31 between the fixed blade and the movable blade by moving the movable blade toward the fixed blade. Although a configuration in which the cutter mechanism 18 is provided is shown, the cutter mechanism 18 may of course be detachable.

[0024] The light sensor 50 shown in Figure 2 is a light sensor for detecting the reflectance of the paper 31. The light sensor 50 irradiates the side wall of the roll paper 30 with light from the light-emitting part and receives the reflected light from the roll paper 30 with the light-receiving part. The side wall of the roll paper 30 refers to the part of the roll paper 30 that has layers in the thickness direction of multiple sheets of paper wound radially. In this embodiment, the area to which light is irradiated is not particularly limited as long as it is the side wall of the roll paper 30.

[0025] In this embodiment, one example of the light sensor 50 uses a reflective type photosensor. While this example of the light sensor 50 includes both a light-emitting unit and a light-receiving unit, the light-emitting unit and the light-receiving unit may be provided separately.

[0026] Furthermore, the sensor used to detect the winding diameter and remaining amount of the roll paper 30 in the conventional configuration may be used as the optical sensor 50 described above.

[0027] In this configuration, printer 1 feeds the paper 31 in the feed direction, prints on it with the thermal head 17, ejects the paper 31 from the leading edge, and cuts it with the cutter mechanism 18. Then, printer 1 switches to the back-feed direction, returns the leading edge of the paper 31 to the printing position of the thermal head 17, and when it receives the next print data, feeds the paper 31 in the feed direction and performs the same operation.

[0028] The damper section 20 shown in Figure 2 is provided between the paper roll 30 storage section 15 and the platen roller 16, and contacts the paper 31 from one side to apply elastic force to the paper 31, thereby maintaining the tension of the paper 31.

[0029] As an example, the damper section 20 has a frame section 26 and a rotating roller 27. The frame section 26 is, for example, a plate-shaped member in the width direction (X direction) of the printer 1, and one end of the frame section 26 is fixed to a pivot axis that rotates the frame section 26. The frame section 26 is also biased in the clockwise direction indicated by arrow A in Figure 2 by a biasing member such as a torsion spring, and is configured to rotate around the pivot axis as a fulcrum. The rotating roller 27 is provided on the other end of the frame section 26 and is capable of rotating in the direction of transporting the paper 31 in contact with the paper 31.

[0030] The first guide section 19 is a guide member for smoothly moving the paper 31 that is transported between the platen roller 16 and the cutter mechanism 18. The second guide section 21 is a guide member for reducing curling that occurs in the paper 31. The second guide section 21 is located opposite the damper section 20.

[0031] As an example, the second guide section 21 has a first member 22 and a second member 23. The first member 22 and the second member 23 are plate members or the like. The first member 22 and the second member 23 have a first contact portion 24 and a second contact portion 25 at one end and one end of the first member 22, respectively. With this configuration, the paper 31 is folded back by the rotating roller 27, the first contact portion 24 and the second contact portion 25, so curling can be reduced.

[0032] Printer 1 operates by receiving power from an external power supply or an internal battery via its control block. Printer 1 may be provided with power terminals and connection terminals used for connecting to external devices such as a host device.

[0033] Figure 3 shows an example of the configuration of the control block of printer 1. As shown in Figure 3, printer 1 has a computer including a CPU (Central Processing Unit) 101, RAM (Random Access Memory) 102, and ROM (Read Only Memory) 103. The CPU 101, RAM 102, and ROM 103 are interconnected via a bus 100 so that they can communicate with each other.

[0034] The CPU 101 executes a predetermined program stored in the ROM 103 and controls the entire printer 1. The RAM 102 is used as a workspace by the CPU 101.

[0035] ROM 103 stores control programs executed by CPU 101 and various data. ROM 103 is, for example, flash memory. The control programs stored in ROM 103 include a print density control program 1000 for performing logic settings (described later), threshold data 1001, and print density table 1002 data.

[0036] In addition, one example printer 1 has a transport controller 104, a head controller 105, a cutter controller 106, a light sensor controller 107, a detection unit 108, a communication controller 109, etc., connected to the bus 100.

[0037] The transport controller 104 is a controller that controls the rotation of the rotating part 60 and the platen roller 16 using a motor or the like. For example, the motor is a stepping motor. The CPU 101 controls the rotation of the rotating part 60 and the platen roller 16 by the transport controller 104 to feed the paper 31 in the feed direction or backfeed direction.

[0038] The head controller 105 is the controller of the thermal head 17. For example, the head controller 105 generates a strobe signal that causes the corresponding heating element of the thermal head 17 to heat up based on the print data received from the CPU 101, and uses the strobe signal to cause the corresponding heating element of the thermal head 17 to heat up.

[0039] The cutter controller 106 is the controller of the cutter mechanism 18. When the cutter controller 106 receives an instruction from the CPU 101, it drives the cutter mechanism 18 to cut the paper 31.

[0040] The light sensor controller 107 is the controller of the light sensor 50. When the light sensor controller 107 receives an instruction from the CPU 101, it causes the light-emitting part of the light sensor 50 to emit light at a predetermined drive current value and outputs an output value to the CPU 101 that corresponds to the current drive value that caused the light-emitting part to emit light and the amount of light received by the light-receiving part. The output value may use other information as appropriate, as long as it is information based on the reflectance of the paper 31. For example, it may be information that shows the ratio of the amount of light irradiated by the light-emitting part to the amount of light received by the light-receiving part.

[0041] The detection unit 108 outputs detection signals from other sensors in the printer 1 to the CPU 101. For example, these include an open / close sensor that detects the opening and closing of the second housing 12, a detection sensor that detects when the roll paper 30 is stored, and a position sensor that detects the paper transport position. In addition, a temperature sensor that measures the temperature of the thermal head 17 may also be provided.

[0042] The communication controller 109 is a controller that allows the CPU 101 to communicate with a host device such as a POS terminal. The communication controller 109 communicates using methods such as infrared communication (IrDA), USB (Universal Serial Bus), LAN (Local Area Network), RS-232C, Bluetooth (registered trademark), etc.

[0043] In the printer 1 configured as described above, for example, the CPU 101 receives print data transmitted from the host device via the communication controller 109. The received print data is temporarily stored in the RAM 102, and the CPU 101 controls and drives each part of the printer 1 to print characters, images, etc., corresponding to the print data onto the paper 31.

[0044] More specifically, the CPU 101 controls the transport controller 104 to transport the paper 31 in the feed direction. The CPU 101 also controls the head controller 105 based on the print data to print characters, images, etc., corresponding to the print data onto the paper 31 at the position of the thermal head 17. Next, when the printed paper 31 is ejected from the output port 13, the CPU 101 stops transporting in the feed direction and controls the cutter controller 106 to cut the printed portion of the paper 31. Then, the CPU 101 controls the transport controller 104 to transport the leading edge of the paper 31 in the backfeed direction to the printing position of the thermal head 17 and waits until it receives the next print data.

[0045] Figure 4 shows an example of the data structure of the print density table 1002. The print density table 1002 shown in Figure 4 has a data structure that shows the correspondence between paper type 1101, printing energy 1102, and corresponding print transport speed 1103.

[0046] Paper type 1101 is assigned group number information, which groups multiple similar types together. For example, papers are divided into Group 1, Group 2, etc., based on similar color characteristics on the print surface. Group 1 consists of papers commonly used in Japan. Group 2 consists of different types of papers from other countries that have different color characteristics than Group 1.

[0047] Group 2 includes, for example, paper in which a black layer is superimposed on a white base, and a surface layer containing air bubbles is provided on top of the black layer. One example is a paper called Blue4est®. Paper with this structure takes on a gray tint due to light incident on the surface layer. By evaporating the surface layer at high heat using a heating element, the black layer is exposed, and black letters or images are formed on the paper. With this type of paper, the color reproduction of printed characters and images is poorer compared to regular paper, and printing with the same print density settings as Group 1 will not result in optimal density adjustment.

[0048] Group 2 requires more energy 2 than energy 1 for normal paper to achieve optimal density. Here, energy refers to the energy that the heating element applies to the paper, and for Group 2 paper, this needs to be increased by several percent. If the amount of heat generated by the heating element is constant, the energy applied to the paper can be increased by slowing down the print transport speed. For example, the rotation of the platen roller 16 is slowed down by switching the print transport speed from the normal print transport speed 1 to a print transport speed 2 that is slower than print transport speed 1.

[0049] Next, with reference to Figure 5, an example of the print density setting operation performed by printer 1 will be described. In printer 1, the CPU 101 executes the print density control program 1000 (see Figure 3) stored in ROM 103 (see Figure 3), thereby allowing the CPU 101 to function as a control unit that performs print density control, and to comprehensively control the entire system to perform the print density setting operation.

[0050] Printer 1 performs the print density setting operation using the above function when the roll paper 30 is first loaded or replaced. For example, the print density setting operation is performed at the timing of the operational check that takes place after the roll paper 30 is inserted into Printer 1.

[0051] Figure 5 is a flowchart illustrating an example of the print density setting operation performed by printer 1. First, printer 1 (control unit) detects that paper has been loaded (step S1). This step detects that the roll paper 30 has been inserted from the empty storage compartment 15. If the roll paper 30 remains stored and is not removed, the print density setting remains unchanged. In other words, if the roll paper 30 remains stored and is not removed, the previous density setting is retained and no new print density setting operation is performed.

[0052] When the printer 1 (control unit) detects that paper has been loaded, it drives the optical sensor 50 under the control of the optical sensor controller 107 and reads the output value of the optical sensor 50 from the optical sensor controller 107 (step S2).

[0053] Furthermore, the printer 1 (control unit) compares the output value read in step S2 with the threshold value 1001 stored in the ROM 103 (step S3).

[0054] If the output value exceeds the threshold 1001, the printer 1 (control unit) sets a second logic (step S4). The second logic is the print transport control logic corresponding to the print transport speed 2.

[0055] Then, the printer 1 (control unit) feeds the paper under the control of the transport controller 104 (step S5), and further controls the head controller 105 to execute printing (step S6).

[0056] Furthermore, if the output value is less than or equal to the threshold 1001, the printer 1 (control unit) sets the first logic (step S7) and executes steps S5 and S6. The first logic is the print transport control logic corresponding to the print transport speed 1.

[0057] Figure 6 is an explanatory diagram of the threshold determination in step S3. Figure 6 shows a graph showing the relationship between the output value corresponding to the current drive value (set value) of the illumination light emitted from the light sensor 50 and the amount of reflected light received by the light sensor 50 from the side wall of the roll paper 30. As an example, the first manufacturer (thickness 75 mm), the first manufacturer (thickness 48 mm), the second manufacturer (thickness 82 mm), and the second manufacturer (thickness 53 mm) are shown for comparison. Note that "no paper" refers to the case when the roll paper 30 is not stored. "No paper" can be detected in advance by the detection unit 108, but the value for "no paper" is also shown for comparison.

[0058] As shown in Figure 6, as the current drive value of the irradiated light is increased, the output value (voltage equivalent) decreases accordingly, depending on the amount of reflected light received from the side wall of the roll paper 30. In the example shown in Figure 6, the output value is maximum when there is no reflection. The output values ​​of the second manufacturer in Group 2 and the first manufacturer in Group 1 are largely separated into upper distribution a1 and lower distribution a2 of the threshold Th between 1.0V and 1.5V in the range of 6mA to 10mA as shown in Figure 6. Therefore, the light-emitting part of the light sensor 50 is set to irradiate within the range of 6mA to 10mA, and the threshold Th shown in Figure 6 is stored in threshold 1001. Then, during the print density setting operation, the light sensor 50 receives the reflected light from the irradiated light of that setting, and compares the output value with the threshold Th. If the output value exceeds the threshold Th, it is determined to be Group 2, and the energy applied to the paper is increased compared to the case of normal paper (Group 1). Preferably, the irradiation light is set to 7mA and the threshold 1001 is stored as threshold Th (=1.1V). Since there is a difference in output values ​​between "no paper" and "second manufacturer," it is also possible to determine "no paper" from the output value. Alternatively, instead of detecting "no paper" by the detection unit 108, a second threshold can be set between the value shown in the "no paper" graph and distribution a1 to determine "no paper" based solely on the output value, and if "no paper" is detected, the print density setting operation can be excluded.

[0059] Thus, in this embodiment, a group corresponding to the type of paper is determined based on the reflectivity of the paper, and the print density setting corresponding to the determined group is performed.

[0060] In this embodiment, a light sensor 50 that receives reflected light from an illumination light (a predetermined light) irradiated onto the side wall of the roll paper 30 was used as the light sensor for determining the paper group. However, other light sensors may be used as appropriate. One example of other light sensors is a light sensor that receives reflected light from an illumination light irradiated onto the printing surface. The illumination light may be changed to light in a different wavelength range than the illumination light irradiated onto the side wall of the roll paper 30 as appropriate.

[0061] The light sensor corresponding to the printing surface described above is positioned opposite the printing surface of the paper 31. For example, the light sensor corresponding to the printing surface described above is positioned opposite the roll paper 30 on the bottom surface of the storage section 15, which is in contact with the stored roll paper 30. In this configuration, the light sensor corresponding to the printing surface illuminates the printing surface of the paper 31 before it is pulled out from the roll paper 30 and receives the reflected light.

[0062] Furthermore, the optical sensor corresponding to the printed surface described above may be positioned along the transport direction of the paper 31 pulled from the roll paper 30. The position can be determined as appropriate, as long as it is along the transport path to the discharge port 13, such as immediately after the paper is pulled from the roll paper 30.

[0063] The optical sensor corresponding to the printing surface described above may be newly installed, or it may be included in the existing device for another purpose; if so, the existing one may be used as a substitute.

[0064] In the configuration described above, which includes at least an optical sensor 50 (first optical sensor) that receives reflected light from an illumination light irradiated onto the side wall of the roll paper 30, and an optical sensor (second optical sensor) that receives reflected light from an illumination light irradiated onto the printing surface, the paper group can be determined using the output value of the first optical sensor and the output value of the second optical sensor. For example, the second logic is set when either the output value of the first optical sensor or the output value of the second optical sensor exceeds a threshold. Another example is setting the second logic when both the output value of the first optical sensor and the output value of the second optical sensor exceed a threshold. These two determination methods may be set as appropriate depending on the printer.

[0065] Another example of a light sensor is one that receives reflected light from an illumination light that is shone on the non-printing surface, which is the back surface of the printing surface. The illumination light may be appropriately changed to light in a different wavelength range than the illumination light shone on the side wall of the roll paper 30.

[0066] The light sensor corresponding to the non-printable surface described above is positioned opposite the non-printable surface of the paper 31. The light sensor corresponding to the non-printable surface described above is positioned along the transport direction of the paper 31 as it is pulled out from the roll paper 30, and illuminates the non-printable surface of the paper 31 to receive the reflected light. The position can be determined as appropriate as long as it is along the transport path to the output port 13, such as immediately after the paper is pulled out from the roll paper 30.

[0067] The optical sensor corresponding to the non-printed surface mentioned above may be newly installed, or it may be configured in the existing device for another purpose, in which case the existing one may be used as a substitute. For example, if the existing device has a sensor that detects black marks, that sensor may be used as a substitute as appropriate.

[0068] In the configuration described above, which includes at least an optical sensor 50 (first optical sensor) that receives reflected light from an illumination light irradiated onto the side wall of the roll paper 30, and an optical sensor (third optical sensor) that receives reflected light from an illumination light irradiated onto the non-printable surface, the paper group can be determined using the output value of the first optical sensor and the output value of the third optical sensor. For example, the second logic is set when either the output value of the first optical sensor or the output value of the third optical sensor exceeds a threshold. Another example is setting the second logic when both the output value of the first optical sensor and the output value of the third optical sensor exceed a threshold. These two determination methods may be set as appropriate depending on the printer.

[0069] Furthermore, the configuration may also include a first optical sensor, a second optical sensor, and a third optical sensor. In this configuration, the output values ​​of the first optical sensor, the second optical sensor, and the third optical sensor can be used to determine the paper group. For example, the second logic is set when one or more of the output values ​​of the first optical sensor, the second optical sensor, and the third optical sensor exceed a threshold. Another example is setting the second logic when the output values ​​of the first optical sensor, the second optical sensor, and the third optical sensor all exceed a threshold. These two determination methods may be set as appropriate depending on the printer. In addition, the respective illuminating lights may be changed to light in different wavelength ranges as appropriate.

[0070] In this embodiment, with the configuration described above, even when using different groups of paper with varying color characteristics on the printed surface, the system can automatically adjust to the optimal density setting.

[0071] (Modified examples of the embodiment) The embodiment describes a method for determining the group of paper 31 by irradiating the side wall of the roll paper 30 with light from the light-emitting part using the light sensor 50 and receiving the reflected light from the roll paper 30, based on the reflectance of the paper 31. Below, a modified example is shown in which the group of paper 31 is determined by detecting the reflectance of the printed portion and the blank portion of the paper 31.

[0072] Figure 7 shows an example of the internal device configuration of printer 1 according to a modified embodiment. In Figure 7, in order to show a modified version of the optical sensor 50 shown in Figure 2, the main parts related to the optical sensor 50 are extracted from Figure 2 and shown. In Figure 7, the parts corresponding to the configuration shown in Figure 2 are given the same numbers. In Figure 7, other configurations are omitted from the illustration, but may be included in the configuration of Modified Example 2 as appropriate.

[0073] As shown in Figure 7, the modified printer has a first optical sensor 51-1 and a second optical sensor 51-2 as optical sensors for determining groups of paper 31.

[0074] The first light sensor 51-1 and the second light sensor 51-2 each irradiate light onto the printing surface area of ​​the paper 31 where printing is performed by the thermal head 17.

[0075] The first light sensor 51-1 shines light onto the unprinted portion (also called the blank portion) of the printing surface and receives the reflected light from the blank portion.

[0076] The second light sensor 51-2 irradiates light onto the area 310 on the printing surface that has been printed by the thermal head 17 (referred to as the printed area), and receives the reflected light from the printed area 310.

[0077] Alternatively, whether a section is blank or printed can be determined by receiving light (green, red, blue, infrared) in different wavelength ranges using an optical sensor and analyzing the output results.

[0078] Figure 8 is a flowchart showing an example of the print density setting operation performed by the modified printer. Note that processes that do not require explicit explanation have been omitted in Figure 8.

[0079] First, the modified printer (control unit) feeds the paper under the control of the transport controller 104 and controls the head controller 105 to print a test pattern at the timing of the operation check that is performed after the roll paper 30 has been inserted (step S11).

[0080] Next, the modified printer (control unit), under the control of the optical sensor controller 107, irradiates the blank area with light using the first optical sensor 51-1 and reads the first output value (output value corresponding to the reflectance of the blank area), which is the output value of the first optical sensor 51-1 corresponding to the reflected light from the blank area (step S12).

[0081] Furthermore, in the modified printer (control unit), under the control of the optical sensor controller 107, the second optical sensor 51-2 irradiates light onto the printing area 310 and reads a second output value (an output value corresponding to the reflectance of the printing area 310), which is the output value of the second optical sensor 51-2 corresponding to the reflected light from the printing area 310 (step S13).

[0082] Step S12 and Stick S13 may be performed simultaneously, or in a different order.

[0083] Next, the modified printer (control unit) performs a delta calculation (step S14). The delta calculation is the difference between the first output value read in step S12 and the second output value read in step S13.

[0084] Next, the modified printer (control unit) determines the group based on the delta calculation result (step S15). The modified printer (control unit) determines the group of paper by comparing the group determination threshold 1001 stored in the ROM 103 with the delta calculation result.

[0085] Next, the modified printer (control unit) sets the logic corresponding to the identified group (step S16). The logic is the print transport control logic.

[0086] Then, the modified printer (control unit), upon receiving print data from the POS device, further feeds paper under the control of the transport controller 104 (step S17), and further controls the head controller 105 to execute printing (step S18).

[0087] Figure 9 is an explanatory diagram for delta calculation and group discrimination. Figure 9(a) is an explanatory diagram for delta calculation. Figure 9(a) is a table in which paper is grouped into multiple similar types.

[0088] As an example, the papers are divided into four groups: Paper Type Group 1, Paper Type Group 2, Paper Type Group 3, and Paper Type Group 4. One way to divide the papers is to group those with similar color characteristics on the print surface. In this example, Paper Type Group 1, Paper Type Group 2, and Paper Type Group 3 are standard papers from domestic manufacturers. Paper Type Group 4 is a different group from overseas.

[0089] Paper type group 4, for example, is a paper in which a black layer is superimposed on a white base, and a surface layer containing air bubbles is provided on top of the black layer. Paper type groups 1, 2, and 3 are ordinary papers.

[0090] In the table shown in Figure 9(a), for example, paper type group 1 associates paper from manufacturers 1, 2, and 3 as the same type of paper, and the readings of the first optical sensor 51-1 and the second optical sensor 51-2 (output values ​​V corresponding to the reflectivity of the paper) when each of the papers from manufacturers 1, 2, and 3 were tested are embedded in their respective corresponding locations.

[0091] For example, the "blank (unprinted area)" in the table is populated with the reading from the first optical sensor 51-1 (output value V corresponding to the reflectance of the blank area). The "100% duty cycle (printed area)" in the table is populated with the reading from the second optical sensor 51-2 (output value V corresponding to the reflectance of the printed area 310). Note that "100% duty cycle (printed area)" refers to the printed area 310 when printed with 100% solid color.

[0092] The "delta calculation" is the value obtained by subtracting the value of the "blank (unprinted area)" (output value V corresponding to the reflectance of the blank area) from the value of the "100% duty cycle (printed area)" (output value V corresponding to the reflectance of the printed area 310). The "delta calculation" in the table is populated with the respective delta calculation values ​​(ΔV).

[0093] Based on the value (ΔV) entered in the "Delta Calculation" column in the table, paper from manufacturers with similar values ​​has been pre-grouped as the same type of paper.

[0094] Figure 9(b) is an explanatory diagram for group discrimination. In Figure 9(b), the delta calculation values ​​(ΔV) from the table in Figure 9(a) are shown as a bar graph. As shown in Figure 9(b), grouping allows for the distinction of group clusters.

[0095] In the example shown in Figure 9(b), paper type group 4, which is a distinct group from the others, can be distinguished from the other groups by setting the threshold Th1, as the difference in values ​​is large.

[0096] Furthermore, because delta calculations were performed, the distinction between paper type group 1, paper type group 2, and paper type group 3 can also be made by setting thresholds Th2, Th3, and Th4, respectively, as shown in the example in Figure 9(b).

[0097] For example, if step S14 of the print density setting operation shown in Figure 8 yields a delta calculation result within the range of paper type group 2, it will take a value between threshold Th2 and threshold Th3. Therefore, by comparing threshold Th2 and threshold Th3, the paper type is classified as group 2 based on the delta calculation result.

[0098] In the modified example shown above, a first optical sensor 51-1 is provided to detect the reflectance of the blank area, and a second optical sensor 51-2 is provided to detect the reflectance of the printing area 310. However, it is also possible to provide only one optical sensor and perform the detection of the reflectance of the blank area and the reflectance of the printing area 310 before and after transporting the paper. In that case, either the first optical sensor 51-1 alone or the second optical sensor 51-2 alone may be used. If only the second optical sensor 51-2 is used, the reflectance of the printing area 310 is detected by backfeeding the paper after printing.

[0099] Thus, the modified configuration can detect the reflectance of the printed and blank portions of the paper 31. Furthermore, since delta calculations are performed from the respective detection results, it becomes possible to distinguish groups that cannot be distinguished by the side walls of the roll paper alone. Even within the same group, it is possible to further subdivide them and set the optimal density for each.

[0100] (Other embodiments) In the embodiments and modifications described above, the density setting method that can be performed by the printer may be provided as a density setting device incorporated into the printer, or it may be provided as a density setting device separate from the printer.

[0101] Figure 10 shows an example of the configuration of a density setting device according to another embodiment. The density setting device 2 shown as an example in Figure 10 has a print density control unit 200 and a memory 250.

[0102] The print density control unit 200 includes an optical sensor information reading unit 201, a threshold determination unit 202, and a print density setting unit 203. The memory 250 stores the threshold 1001 and the print density table 1002. The memory 250 may be a volatile memory, a non-volatile memory, or storage.

[0103] The optical sensor information reading unit 201 emits light from a predetermined optical sensor provided in the printer and reads the output value output from the optical sensor.

[0104] The threshold determination unit 202 compares the output value read by the optical sensor information reading unit 201 with the threshold value 1001 stored in the memory 250.

[0105] The print density setting unit 203 sets the corresponding logic from the print density table 1002 stored in the memory 250 to the printer based on the comparison result from the threshold determination unit 202.

[0106] In this way, by configuring the density setting device 2, the functionality of an existing printer equipped with a light sensor 50 can be improved by applying the density setting device 2.

[0107] Furthermore, while we have shown an example of detecting the reflectance of paper using an optical sensor, if an existing printer is equipped with an optical sensor that detects the output of transmitted light from the light irradiated onto the paper, or if the arrangement is limited to an optical sensor that detects the output of transmitted light from the light irradiated onto the paper, the transmittance of the paper may be detected by that optical sensor as an alternative to reflected light, and the density setting method described above may be modified so that it can be applied.

[0108] The programs executed by the printer 1 in the embodiments and modified versions are provided as installable or executable files recorded on a computer-readable recording medium such as a CD-ROM, flexible disk (FD), CD-R, or DVD (Digital Versatile Disk).

[0109] Furthermore, the program executed by the printer 1 of the embodiment and its modifications may be stored on a computer connected to a network such as the Internet and provided by being downloaded via the network. Alternatively, the program executed by the printer 1 of the embodiment and its modifications may be provided or distributed via a network such as the Internet.

[0110] Furthermore, the program to be executed by the printer 1 of the embodiment and its modified form may be pre-installed and provided in ROM or the like.

[0111] Although embodiments of the present invention have been described above, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, substitutions, modifications, and combinations are possible without departing from the spirit of the invention. These embodiments and their variations are included in the scope and spirit of the invention, as well as in the claims of the invention and its equivalents. [Explanation of symbols]

[0112] 1. Printer 13 Outlet 15. Storage area 16 Platen Roller 17 Thermal Head 18 Cutter mechanism 20 Damper section 30 rolls of paper 31 sheets 50 Light Sensors 60 Rotating part 100 bus 101 CPU 102 RAM 103 ROM 104 Transport Controller 105 Head Controller 106 Cutter Controller 107 Light Sensor Controller 108 Detection unit 109 Communication Controller 1000 Print density control program 1001 threshold 1002 Print density table [Prior art documents] [Patent Documents]

[0113] [Patent Document 1] Japanese Patent Application Publication No. 4-90365

Claims

1. A printing means for printing on a medium, A light sensor that receives reflected light of a predetermined light irradiated onto the medium before printing, A density setting means that sets the print density for a group corresponding to the type of medium based on the output value output by the light sensor upon receiving the reflected light, A printer equipped with [a specific feature / feature].

2. The area to which the predetermined light is irradiated is the roll-shaped side wall of the medium. The printer according to claim 1.

3. Equipped with multiple optical sensors, The plurality of optical sensors include, at least, a first optical sensor that receives a first reflected light which is the reflected light of a predetermined light irradiated onto the side wall, and a second optical sensor that receives a second reflected light which is the reflected light of a predetermined light irradiated onto the printing surface of the medium. The printer according to claim 2.

4. Equipped with multiple optical sensors, The plurality of optical sensors include, at least, a first optical sensor that receives a first reflected light which is the reflected light of a predetermined light irradiated onto the side wall, and a second optical sensor that receives a second reflected light which is the reflected light of a predetermined light irradiated onto the back surface of the printing surface of the medium. The printer according to claim 2.

5. The light sensor receives reflected light from a predetermined light irradiated onto the unprinted portion of the medium before printing and outputs a first output value, and receives reflected light from the predetermined light irradiated onto the printed portion of the medium after printing and outputs a second output value. The density setting means sets the print density for a group corresponding to the type of medium based on the first output value and the second output value. The printer according to claim 1.

6. Having group information with the same concentration setting, The density setting means sets the print density corresponding to the group from a plurality of groups according to the calculation result calculated from the first output value and the second output value. The printer according to claim 5.

7. A density setting device for a printer comprising a printing means for printing on a medium and a light sensor for receiving reflected light of a predetermined light irradiated onto a target area of ​​the medium, A density setting device comprising density setting means for setting a print density corresponding to an output value output from the light sensor based on the reflected light of a predetermined light irradiated onto the target area, in accordance with the output value.

8. On the computer, The steps include: irradiating a medium before printing with reflected light of a predetermined light and receiving the reflected light of the predetermined light irradiated onto the medium; The steps include setting the print density for a group corresponding to the type of medium based on the output value of the reflected light, A program that executes the command.

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