JP2009255496A - Printing method and printer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a printer which need not associate the type of a roll body with the diameter thereof in advance but can obtain the diameter of an optional attached roll body, and a method for obtaining the diameter of the roll body in the printer. <P>SOLUTION: The printer 1 to which the roll body 3 around which a belt-like recording medium 2 is wound is attached and which performs recording to the recording medium 2 fed from the roll body 3 includes: a roll body rotational amount detection means 17 detecting the rotational amount of the roll body 3; a conveying amount detection means 18 detecting the conveying amount of the recording medium 2 conveyed as the roll body 3 rotates; and an arithmetic means 25 obtaining the diameter of the roll body 3 on the basis of the rotational amount and the conveying amount. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to a printing method and a printing apparatus.

  In the printing apparatus, a roll body in which a strip-shaped recording paper is wound in a roll shape is accommodated in a roll body accommodating portion, and the recording paper wound in the roll body is moved in the direction of the recording head by a paper feed roller. There is one that records on the drawn recording paper (see Patent Document 1).

In such a printing apparatus, there is a possibility that the recording by the recording head is disturbed if the recording paper in the portion where recording is performed by the recording head is slack. Therefore, the roll body is provided with a torque limiter that generates a predetermined torque in the direction opposite to the pulling direction based on the diameter of the roll body (the remaining amount of recording paper), and the rotation of the paper feed roller is controlled according to this torque. Thus, tension is generated in the recording paper drawn by the paper feed roller. In this case, it is necessary to know the diameter of the roll body. For the diameter of the roll body, the weight of the roll body is measured, the remaining amount of recording paper is obtained from this weight, and the diameter of the roll body is calculated (patent) Reference 1).
JP 2007-245544 A

  However, in the case of the method of calculating the diameter based on the weight of the roll body, the weight may vary depending on the material of the recording paper even if the diameter is the same, and even if the weight is the same, the core around which the recording paper is wound The diameter may vary depending on the thickness (diameter) of the (cylinder). Therefore, in order to measure the diameter of the roll body, it is necessary to associate in advance the weight and diameter for each type of roll body, such as the material of the recording paper and the thickness of the winding core. Therefore, the diameter of a roll body without such correspondence cannot be calculated.

  Therefore, the present invention eliminates the need to associate the type of roll body and its diameter in advance, and can determine the diameter of a mounted roll body and a method for determining the diameter of the roll body in a printing apparatus. The purpose is to provide.

  In order to solve the above-described problem, a roll body around which a belt-shaped recording medium is wound is mounted, and when recording is performed on the recording medium that is wound and conveyed from the roll body, the recording medium is transferred from the roll body. And measuring the diameter of the roll body based on the transport amount of the recording medium and the rotation amount of the roll body at that time (measuring means). By configuring the printing apparatus in this way, it is not necessary to associate the types of roll bodies with their diameters in advance, and the diameter of any mounted roll body can be obtained.

  As an example of a specific configuration of the present invention, the conveyance amount may be measured based on the rotation amount of the paper feed roller that conveys the recording medium, or the rotation amount of the driven roller that rotates following the conveyance of the recording medium. The conveyance amount may be measured based on the above. By comprising in this way, the detection accuracy of the conveyance amount of a recording medium improves, and the diameter of a roll body can be calculated | required with high precision.

  As described above, once the diameter of the roll body is measured, the diameter of the roll body that decreases with the conveyance of the recording medium during the subsequent recording can be obtained without measurement. . Therefore, the correspondence relationship between the remaining amount of the recording medium in the roll body and the diameter of the roll body is investigated in advance, and the correspondence relationship is stored as the first correspondence relationship. Since the diameter of the roll body decreases as the remaining amount of the recording medium in the roll body decreases, a unique correspondence can be prepared. Then, the remaining amount of the recording medium is acquired based on the conveyance amount of the recording medium conveyed during printing, and the diameter of the roll body after printing is estimated based on the remaining amount and the first correspondence relationship.

  That is, the remaining amount of the recording medium after use is calculated based on the original remaining amount and the transport amount transported during use. When the remaining amount of the recording medium after use is obtained, the diameter of the roll body after use can be acquired based on the remaining amount and the first correspondence relationship. Here, since it is not necessary to measure other than the transport amount at the time of use, the diameter can be easily obtained. That is, the current diameter of the roll body can be obtained without measuring the amount of rotation of the roll body each time the recording medium is used.

  In addition to the first correspondence relationship, the correspondence relationship between the diameter of the roll body and the static load is stored as a second correspondence relationship, and the static load after use is based on the diameter and the second correspondence relationship. May be obtained. The diameter of the roll body and the static load can be considered to have a unique correspondence, and the load can be acquired by the same method as the diameter of the roll body. Various factors can be considered for the static load, but the resistance due to the weight of the roll body is one of the main factors. Since the weight of the roll body decreases as the diameter and remaining amount of the recording medium decrease, it can be considered that the diameter of the recording medium and the static load have a unique correspondence.

  Further, since the first correspondence relationship and the second correspondence relationship vary depending on the thickness, specific gravity, and frictional resistance of the recording medium, it is desirable that the first correspondence relationship and the second correspondence relationship correspond to the type of the recording medium. For example, the first correspondence relationship and the first correspondence relationship are provided only when the first correspondence relationship and the second correspondence relationship are of a prepared type, provided with means for receiving detection and input of the type of the recording medium loaded. The diameter and the load may be acquired based on the two correspondence relationship. If the first correspondence relationship and the second correspondence relationship are of a type that is not prepared, measurement by the measuring means may be performed. Of course, the first correspondence and the second correspondence are stored for each recording medium, and the first correspondence and the second correspondence corresponding to the type of the recording medium are selected and used. It may be.

  It can be considered that the weight of the roll body is proportional to the width of the recording medium, and the frictional resistance of the recording medium in the conveyance path is also proportional to the width of the recording medium. Therefore, the width in the direction orthogonal to the conveyance direction of the recording medium may be measured, and the static load after use may be acquired based on the width, the diameter, and the second correspondence relationship. In this way, it is not necessary to store the second correspondence relationship for each width.

  Furthermore, the technical idea of the present invention can be embodied not only in a specific printing apparatus but also in a method including a process performed by the printing apparatus. Of course, when the above-described printing apparatus reads the program and realizes each unit described above, the technical idea of the present invention is also applied to a program for executing a function corresponding to each unit and various recording media on which the program is recorded. Needless to say, can be realized. Needless to say, the printing apparatus of the present invention can be distributed not only by a single apparatus but also by a plurality of apparatuses. Furthermore, the printing apparatus of the present invention may be incorporated in an apparatus having other functions. For example, the printing apparatus of the present invention may be incorporated in a composite apparatus having a scanner function and a fax function.

(First embodiment)
Hereinafter, a first embodiment of the present invention will be described with reference to the drawings. A method for obtaining the diameter of the roll body and the static load on the recording medium in the printing apparatus will be described in accordance with the operation of the printer 1.

(Entire printer configuration)
FIG. 1 is a perspective view showing an appearance of a printer 1 as a printing apparatus according to the first embodiment of the present invention. FIG. 2 is a configuration diagram showing a schematic configuration of the printer 1. FIG. 3 is a block diagram illustrating an electrical configuration of the printer 1. 1 and 2, the arrow X direction is the front (front side), the opposite direction is the rear (rear side), the arrow Y direction is the lower side (lower side), and the opposite direction is the upper side (upper side). To do. Further, from the rear to the front, the right hand side is the right side (right side), and the left hand side is the left side (left side). FIG. 2 is a configuration diagram of the printer 1 as viewed from the left side.

  The printer 1 is configured as a printer in which a roll body 3 in which a strip-shaped recording paper 2 as a recording medium is wound in a roll shape is accommodated, and recording can be performed on the recording paper 2 drawn out from the roll body 3. ing. The printer 1 includes a roll body accommodating portion 4 in which the roll body 3 is accommodated, a paper feeding mechanism 5 that conveys the recording paper 2 while being drawn downward from the roll body 3 accommodated in the roll body accommodating portion 4, and the recording paper 2. A recording mechanism 6 that performs recording by ejecting ink, a guide plate 7 that supports the rear side of the recording paper 2 drawn from the roll body 3, and the like. Contained. A leg portion 9 is provided at the lower portion of the exterior housing 8, and the printer 1 is installed on the floor surface or the like by the leg portion 9.

  The roll body accommodating portion 4 is disposed at the upper part of the printer 1, and a paper feeding mechanism 5 and a recording mechanism 6 are disposed below the roll body accommodating portion 4. The recording paper 2 is drawn downward from the roll body 3 by the paper feed mechanism 5 and conveyed downward with the rear surface guided by the guide plate 7. Then, recording is performed on the recording paper 2 conveyed downward by the recording mechanism 6. The recording paper 2 on which recording has been performed by the recording mechanism 6 is sent downward by the paper feeding mechanism 5 and is discharged to the outside from a discharge port (not shown) formed in the lower portion of the exterior housing 8.

  The roll body 3 has a configuration in which the recording paper 2 is wound around a hard cylindrical body 10. The roll body accommodating portion 4 includes a pair of left and right roll support shafts 11R and 11L that are inserted into the inside of the cylindrical body 10 from the left and right openings of the cylindrical body 10 and support the roll body 3 in the roll body accommodating portion 4. It has been. A roll motor 13 is connected to the left roll support shaft 11L via a gear train 12. On the other hand, the right roll support shaft 11R is freely rotatable with respect to the printer 1. Therefore, by driving the roll motor 13, the roll support shaft 11L rotates, and the roll body 3 rotates together with the roll support shafts 11R and 11L while being supported by the roll support shafts 11R and 11L. .

  The roll motor 13 is, for example, one having a shaft rotational torque of about 100 grams. On the other hand, a heavy roll body 3 whose weight may exceed 5 kilograms or 10 kilograms may be supported on the roll support shafts 11R and 11L, for example. Therefore, the gear train 12 has a reduction ratio of, for example, 50 to 100 so that the roll body 3 can be rotated even when the heavy roll body 3 is supported by the roll support shafts 11R and 11L. A large reduction ratio is set.

  The paper feeding mechanism 5 has a function of conveying the recording paper 2 drawn out from the roll body accommodating portion 4 downward and discharging it from a discharge port (not shown). The paper feed mechanism 5 includes a paper feed roller 15 that is rotationally driven by a paper feed motor 14 (see FIG. 3), and a driven roller 16 that is driven to rotate in pressure contact with the paper feed roller 15. The paper feed roller 15 is attached to the output shaft of the paper feed motor 14, and the rotation amount of the output shaft of the paper feed motor 14 and the rotation amount of the paper feed roller 15 correspond to 1: 1. That is, the reduction ratio from the paper feed motor 14 to the paper feed roller 15 is 1.

  The recording paper 2 drawn out from the roll body 3 is sandwiched between the paper feed roller 15 and the driven roller 16, and is conveyed downward under the rotation of the paper feed roller 15. At this time, the roll body motor 13 is driven so as to rotate the roll body 3 in the direction (forward rotation direction) in which the recording paper 2 is sent out from the roll body 3. That is, the recording paper 2 is conveyed from above to below by the paper feed roller 15 rotated by the paper feed motor 14 and the roll body 3 rotated in the normal rotation direction by the roll body motor 13.

  When carrying, the rotation of the roll motor 13 is controlled so that the recording paper 2 between the paper feed mechanism 5 and the roll body 3 has a certain tension. By making the tension of the recording paper 2 between the paper feed mechanism 5 and the roll body 3 positive in the pulling direction, it is possible to prevent the recording paper 2 between the paper feed mechanism 5 and the roll body 3 from sagging. . Further, the slip amount between the recording paper 2 and the paper feed roller 15 is stabilized, and the conveyance amount of the recording paper 2 can be stabilized.

  A rotary encoder 17 (see FIG. 3) as a roll body rotation amount detecting means for detecting the rotation amount of the roll body 3 is attached to the output shaft of the roll body motor 13 described above. A rotary encoder 18 (see FIG. 3) is attached to the output shaft of the paper feed motor 14. Therefore, the rotary encoder 17 can detect the rotation amount and the rotation speed of the roll body motor 13, and the rotary encoder 18 can detect the rotation amount and the rotation speed of the paper feed motor 14.

  The recording mechanism 6 includes a recording head 19, a carriage 20 to which the recording head 19 is attached, a carriage guide shaft 21 that guides the movement of the carriage 20 in the left-right direction (main scanning direction), and a timing belt (not shown). And a carriage motor 22 (see FIG. 3) that moves the carriage 20 in the left-right direction. The carriage 20 receives the driving force of the carriage motor 22 and reciprocates in the left-right direction along the carriage guide shaft 21, and the recording head 19 also moves in the left-right direction together with the carriage 20. Then, the recording head 19 is moved to a predetermined position on the recording paper 2 by moving the recording head 19 in the left-right direction and moving the recording paper 2 from the upper side to the lower side by the paper feeding mechanism 5. Make a record. By stabilizing the transport amount of the recording paper 2 as described above, the relative position between the recording head 19 and the recording paper 2 can be controlled as intended, and uneven recording (ink density) such as banding can be prevented. And high-quality recording results can be obtained.

(Configuration of circuit block)
Next, an outline of the electrical configuration of the printer 1 shown in FIGS. 1 and 2 will be described with reference to FIG. In FIG. 3, the printer 1 includes an interface 23 that receives image forming data input from the host computer HC, a control unit 24, a roll body motor 13, and a roll body motor driver 13 </ b> D that drives the roll body motor 13. , A paper feed motor 14, a paper feed motor driver 14D for driving the paper feed motor 14, a recording head 19, a recording head driver 19D for driving and controlling the recording head 19, a carriage motor 22, and the carriage motor 22 Carriage motor driver 22D to be driven, rotary encoder 17, rotary encoder 18, and paper width sensor 31 for measuring the width of the recording paper 2 conveyed in the vicinity of the recording head 19 (the length in the direction orthogonal to the conveying direction) Have

  The control unit 24 performs various operations of the printer 1 in addition to recording control of the recording head 19 and drive control of the roll motor 13, paper feed motor 14, carriage motor 22 and the like based on a recording start signal, image formation data, and the like. A CPU (Central Processing Unit) 25 for controlling the control, a PROM (Programmable Read-Only Memory) 26 in which processing programs relating to various operations of the printer 1 are stored, and the host computer HC are input via the interface 23. A RAM (Random Access Memory) 27 that stores and stores image formation data and the like, and functions as a working memory, and an EEPROM (Electrically Erasable Programmable Read-Only Memory) 28 that stores various information related to the printer 1 are provided.

(Overall flow)
FIG. 4 shows a schematic flow of the overall processing executed by the printer 1 of the present embodiment. In step S <b> 100, the control unit 24 detects that the roll body 3 has been attached (replaced) to the roll body housing part 4. For example, the mounting of the roll body 3 on the roll body housing unit 4 may be detected by a sensor (not shown), or the mounting of the roll body 3 may be detected in response to an operation on an operation panel (not shown). In the present embodiment, the operation panel (not shown) accepts that the roll body 3 is mounted and the type of the recording paper 2 wound around the roll body 3 (for example, plain paper, glossy paper, matte paper). Shall be. Information for identifying the type of the received recording sheet 2 is stored in the EEPROM 28. Next, the control part 24 performs a measurement process in step S200. In this measurement process, the diameter D of the roll body 3 immediately after the roll body 3 is mounted and the roll static load (torque) when the roll body 3 rotates are measured. Since this roll static load varies linearly according to the rotation speed of the roll body 3 (conveying speed V of the recording paper 2), the static load Nhi during high speed conveyance and the static load Nlo during low speed conveyance are measured. Keep it. When the measurement process is completed, the static loads Nlo, Nhi and the diameter D are stored in the EEPROM 28.

  When the measurement process is completed, the printer is ready for printing, and an input of a print job from the host computer HC is accepted in step S300. In step S400, print processing for the accepted print job is executed. When the printing process is completed, it is determined whether or not the recording paper 2 of the loaded roll 3 is a plain paper (step S450). If the printing paper 2 is a plain paper, an estimation process is executed in step S500. . In this estimation process, the diameter D of the roll body 3 and the static loads Nlo and Nhi immediately after the printing process are acquired, and these are updated in the EEPROM 28. When the estimation process is completed, the process returns to step S300. On the other hand, when the recording sheet 2 of the mounted roll body 3 is not plain paper, the process returns to step S200 and the measurement process is executed. That is, the static loads Nlo, Nhi and the diameter D are acquired by the measurement process and updated to the EEPROM 28.

As described above, in the present embodiment, first, when the roll body 3 is mounted, the measurement process is performed, and the static loads Nlo and Nhi stored in the EEPROM 28 each time the print process is completed (every use) The diameter D is to be updated. However, when the recording sheet 2 of the mounted roll body 3 is plain paper, the static loads Nlo, Nhi and the diameter D are acquired by the measurement process for the first time, and the static loads Nlo, Nhi and the diameter D are acquired for the second time and thereafter. Is obtained by estimation processing. On the other hand, when the recording paper 2 of the mounted roll body 3 is not plain paper, the static loads Nlo and Nhi and the diameter D are acquired by measurement processing every time. Note that the printer 1 may transport the recording paper 2 other than the printing process. For example, a case where the recording paper 2 is transported (used) during maintenance can be considered. Even when such an operation is performed, it is desirable to execute a measurement process or an estimation process in order to update the static loads Nlo, Nhi and the diameter D. Next, the measurement process will be described.
(Measurement process)
First, the measurement process will be described with reference to FIGS. FIG. 5 is a flowchart showing the operation of the printer 1 when measuring the diameter of the roll body 3 in the printer 1. FIG. 6 shows the relationship between the conveyance of the recording paper 2 by the paper feed roller 15 and the rotation of the roll body 3. FIG. FIG. 7 is a graph showing changes in the count amounts of the rotary encoders 17 and 18 when the diameter of the roll body 3 is measured. That is, the graph of FIG. 7 shows changes in the rotation amounts of the roll motor 13 and the paper feed motor 14. FIG. 8 shows an example of the relationship between the rotation amount (conveyance speed) of the paper feed motor 14 and the static load.

  By the way, if there is no slip between the paper feed roller 15 and the recording paper 2 and between the roll body 3 and the recording paper 2, the conveyance amount of the recording paper 2 by the paper feed roller 15 and the recording paper 2 The conveyance amount of the recording paper 2 by the roll body 3 rotated with the conveyance is equal. Accordingly, the conveyance amount of the recording paper 2 by the paper feed roller 15 is measured as the conveyance amount of the recording paper 2 by the roll body 3, and the rotation angle of the roll body 3 corresponding to the conveyance amount of the recording paper 2 by the roll body 3 is measured. , The diameter of the roll body 3 can be known based on the relationship between the circumference and the diameter.

  Therefore, in the present embodiment, the conveyance amount of the recording paper 2 by the paper feed roller 15 is measured, and the rotation angle of the roll body 3 rotated as the recording paper 2 is conveyed is measured. Based on the above, the diameter of the roll body 3 is obtained. The conveyance amount of the recording paper 2 corresponds to the rotation amount of the paper feed roller 15, and this rotation amount can be measured by the rotary encoder 18. That is, the outer peripheral length of the paper feed roller 15 is constant and can be known in advance as a known value. Further, the number of rotations of the paper feed roller 15 for conveying the recording paper 2 can be measured by the count amount of the rotary encoder 18. Therefore, the transport amount of the recording paper 2 is determined based on the known outer peripheral length of the paper feed roller 15 and the count amount of the rotary encoder 18 corresponding to the rotation amount of the paper feed roller 15 rotated to transport the recording paper 2. Can be sought.

  When the rotation angle of the roll body 3 is measured, the roll body 3 is not rotated despite the recording paper 2 being conveyed, that is, the recording paper 2 between the paper feed roller 15 and the roll body 3. When the slack is generated, the rotation angle of the roll body 3 corresponding to the conveyance amount of the recording paper 2 cannot be measured. As a result, the diameter of the roll body 3 cannot be determined accurately.

  First, a slack eliminating operation for eliminating the slack of the recording paper 2 between the paper feed roller 15 and the roll body 3 is performed (step S10). In the slack elimination (step S10), the paper feed motor 14 is driven to rotate (forward) the paper feed roller 15 in the direction in which the recording paper 2 is conveyed downward. Then, it is determined whether or not the recording paper 2 is slack between the paper feed roller 15 and the roll body 3 (step S20). If it is determined that there is slack (Yes in step S20), the paper feed roller 15 When normal rotation is continued and it is determined that there is no slack (No in step S20), the drive is stopped (step S30). If the state where it is determined that there is slack (Yes in step S20) continues for a predetermined time (Yes in step S25), the process ends in error.

  Whether the recording paper 2 is slack between the paper feed roller 15 and the roll body 3 is determined based on, for example, a duty ratio of PWM voltage control in the voltage applied to the paper feed motor 14. That is, when the paper feed roller 15 is rotated at a certain speed and the duty ratio is equal to or less than a certain value, it can be determined that the rotational load of the paper feed motor 14 is small and the recording paper 2 is slack. On the contrary, when the duty ratio exceeds a certain value, it can be determined that the rotational load of the paper feed motor 14 is large and tension is generated on the recording paper 2 between the paper feed roller 15 and the roll body 3. Further, if the slack is not resolved even if the paper feed roller 15 continues to rotate forward for a predetermined time, for example, a cut sheet is mounted or the roll body 3 is in the opposite direction (the unwinding direction is opposite to the rotation direction). Direction). Therefore, in such a case, the process ends in error.

  If it is determined that there is no slack in the recording paper 2 between the paper feed roller 15 and the roll body 3 (No in step S20), the drive of the paper feed motor 14 is stopped (step S30). The paper feed motor 14 is driven for a predetermined time, for example, 5 seconds so that the feed roller 15 is rotated forward (step S40). The recording paper 2 is conveyed downward by the rotation of the paper feed roller 15, and the roll body 3 rotates in the forward rotation direction according to the conveyance of the recording paper 2 and is connected to the roll body 3 via the gear train 12. 13 also rotates.

  Along with the start of driving of the paper feed motor 14, the rotary encoders 17 and 18 start detecting the rotation amounts of the paper feed motor 14 and the roll motor 13 (step S50). That is, as shown in FIG. 7, the detection of the rotation amounts of the paper feed motor 14 and the roll motor 13 is started from the detection start point A1. In the graph of FIG. 7, the horizontal axis indicates the elapsed time since the driving of the paper feed motor 14 is started, and the vertical axis indicates the rotation amount of the rotary encoders 17 and 18. At the detection start time A1, the count amount by the rotary encoders 17 and 18 is zero. The graph line (1) indicates the count amount by the rotary encoder 17, and the graph line (2) indicates the count amount by the rotary encoder 18. As can be seen from the graph of FIG. 7, while the drive of the paper feed motor 14 is continued, the count amounts of the rotary encoders 17 and 18 increase with the passage of time.

  When the paper feed motor 14 is driven for a predetermined time (Yes in step S60), the drive of the paper feed motor 14 is stopped (step S70). Along with the stop of driving of the paper feed motor 14, the count amount of the rotary encoder 18 is counted (step S80). For example, in the graph of FIG. 7, the count amount of the rotary encoder 18 at the driving stop time A2 of the paper feed motor 14 is measured as Ck. Subsequent to counting the count amount of the rotary encoder 18, a predetermined time t, for example, 0.1 second is passed (step S90), and the count amount of the rotary encoder 17 is counted (step S100). For example, in the graph of FIG. 7, the count amount at this time is measured as Cr1.

  The recording paper 2 itself has some elasticity, and tension is applied to the recording paper 2 between the roll body 3 and the paper feed roller 15. Therefore, even if the driving of the paper feed motor 14 is stopped and the rotation of the paper feed roller 15 is stopped, the roll body 3 is slightly rotated by the influence of the elastic force of the recording paper 2 and is dragged by this, or The roll motor 13 may also rotate due to inertia. Therefore, after the drive of the paper feed motor 14 is stopped, the count amount of the rotary encoder 17 is counted after a predetermined time in anticipation that the rotation of the roll motor 13 is completely stopped. Thereby, the measurement accuracy of the rotation amount of the roll body 3 corresponding to the conveyance amount of the recording paper 2 can be increased.

Subsequently, on the basis of the measured rotation amount Cr1 of the roll body motor 13 and rotation amount Ck of the paper feed motor 14, the diameter of the roll body 3 is calculated by the arithmetic means configured functionally in the CPU 25 (step S110). ). This calculation can be performed based on the following equation.
Lk × (Ck / Rk) = D × π × (Cr1 / Rr) (1)
D = (Lk × (Ck / Rk)) / (π × (Cr1 / Rr)) (2)
Lk: the outer peripheral length of the paper feed roller 15.
Ck: a count amount of the rotary encoder 18.
Rk: a count amount of the rotary encoder 18 when the paper feed motor 14 (paper feed roller 15) makes one rotation.
D: The diameter of the roll body.
π: Pi ratio.
Cr1: Count amount of the rotary encoder 17
Rr: the count amount of the rotary encoder 17 of the roll body motor 13 when the roll body 3 is rotated once, and the reduction ratio of the gear train 12 is set to the count amount of the rotary encoder 17 corresponding to one rotation of the roll body motor 13. Multiplyed value. Cr1 and Ck are measured values, and Lk, Rk, and Rr are known values specific to the printer 1.

  The left side of the equation (1) indicates the amount of rotation on the outer periphery of the paper feed roller 15 when the paper feed motor 14 rotates the count amount Ck, that is, when the paper feed motor 14 rotates Ck / Rk. In other words, if there is no slip between the paper feed roller 15 and the recording paper 2, the left side of Equation (1) is equal to the conveyance amount of the recording paper 2 by the paper feed roller 15. The right side of Expression (2) indicates the amount of conveyance by the roll body 3 when the roll body motor 13 rotates by the count amount Cr1, that is, when the roll body 3 rotates by Cr1 / Rr. That is, if there is no slip between the roll body 3 and the recording paper 2, the right side of Expression (2) is also equal to the conveyance amount of the recording paper 2 by the paper feed roller 15. And the diameter D of the roll body 3 is computable based on Formula (2) which deform | transformed Formula (1). When the diameter D of the roll body 3 is calculated, the static load is continuously measured.

  In the flowchart shown in FIG. 5, the roll motor 13 is driven at a low speed (step S120). In the present embodiment, the rotation of the roll motor 13 is controlled so that the recording paper 2 is conveyed at a constant speed Vlo = 1 ips (inch / sec). That is, the duty ratio of the voltage applied to the roll motor 13 is based on the rotation speed so that the rotation amount (rotation speed) per unit time detected by the rotary encoder 18 becomes a rotation speed corresponding to the constant speed Vlo. Feedback control (for example, PID control). As shown in the above equation (1), the diameter D affects the relationship between the rotation amount of the roll motor 13 and the conveyance speed of the recording paper 2. However, since the diameter D has already been measured, it corresponds to the constant speed Vlo. The rotational speed of the roll body motor 13 to be performed can be specified. Further, by dividing the above equation (1) by time, the rotation speed of the roll body motor 13 can be converted into the conveyance speed by the roll body 3, and the rotation speed corresponding to the speed Vlo can be specified. . Subsequently, it is determined whether or not the rotational speed detected by the rotary encoder 18 is stable (step S130).

  Here, it may be directly determined whether or not the rotational speed is stable based on the measurement of the rotary encoder 18, or may be determined to be stable when a predetermined time has elapsed (acceleration is completed). When the rotation of the roll motor 13 is stabilized, the duty ratio output to the roll motor 13 at that time is acquired as the static load Nlo (step S140). Here, the duty ratio output to the roll body motor 13 is a torque around the axis of the roll body 3 necessary for rotating the roll body 3 at a constant speed Vlo against the rotational resistance acting on the roll body 3. . The duty ratio of the roll body motor 13 can be obtained based on, for example, an integral component of PID control for the roll body motor 13.

  When the static load Nlo when transported at the speed Vlo can be measured as described above, the driving of the roll body motor 13 is stopped (step S150). Subsequently, similar processing (steps S160 to S190) is performed again. However, here, the roll motor 13 is driven at high speed so that the recording paper 2 is conveyed at a constant speed Vhi = 3 ips (inch / sec), and the static load Nhi at that time is measured by the same method as in step S140. (Step S180). FIG. 8 shows an example of the relationship between an arbitrary conveyance speed V and a static load N. As shown in the figure, it is known that the conveyance speed V and the static load N have a linear correspondence relationship. Therefore, the CPU 25 can calculate the static load N at an arbitrary conveyance speed V by linear interpolation based on the static loads Nlo and Nhi at the low speed Vlo and the high speed Vhi. The diameter D and the static loads Nlo and Nhi obtained as described above are stored in the RAM 27 or the EEPROM 28 (step S200).

  If the diameter D and the static loads Nlo and Nhi can be stored in this way, each process can be executed using them thereafter. By the way, when the recording paper 2 is plain paper as shown in FIG. 4, after the diameter D measured by the measurement process and the static loads Nlo and Nhi are stored, the estimation process is executed every time the print process is performed. The

(Estimation process)
FIG. 9 is a flowchart showing the operation of the printer 1 in the estimation process. In the measurement process described above, the roll body 3 is driven for measurement to measure the diameter D and the static loads Nlo and Nhi of the roll body 3, but in the estimation process, for the measurement The diameter D and the static loads Nlo and Nhi of the roll body 3 are measured without driving the roll body 3. The estimation process is executed immediately after the printing process is completed.

  First, in the estimation process, first, the diameter D and the static loads Nlo, Nhi of the roll body 3 stored in the EEPROM 28 are read (step S310). Since the diameter D of the roll body 3 and the static loads Nlo and Nhi are updated each time printing processing is performed, the diameter D and the static loads Nlo and Nhi of the roll body 3 before performing the immediately preceding printing process can be acquired. Next, the conveyance amount ΔR of the recording paper 2 conveyed in the immediately preceding printing process is acquired (step S320). The conveyance amount ΔR of the recording paper 2 in the printing process may be specified based on the image size, margin, etc. of the print data printed by the printer 1, or the rotation amount of the paper feed motor 14 during printing (the above (1) The left side of the expression) may be specified. When the carry amount ΔR can be acquired, the CPU 25 acquires the first correspondence relationship stored in the PROM 26 (step S340).

  FIG. 10 is a graph illustrating an example of the first correspondence relationship CR1. In the figure, the horizontal axis indicates the diameter D of the roll body 3, and the vertical axis indicates the remaining amount R of the recording paper 2 in the roll body 3. As illustrated, the remaining amount R and the diameter D have a parabolic relationship. The first correspondence CR1 can be obtained by a preliminary survey in which the diameter D of the roll body 3 is sequentially measured while the recording paper 2 is gradually conveyed from the roll body 3, or by a theoretical formula based on the thickness of the recording paper 2 or the like. . As shown in FIG. 10, as the recording paper 2 is gradually conveyed from the roll body 3, the remaining amount of the recording paper 2 in the roll body 3 decreases, and the diameter D also monotonously decreases. When the remaining amount of the recording paper 2 becomes zero, the diameter D (excluding the winding core) becomes zero.

  By referring to the first correspondence CR as indicated by the broken line, the remaining amount R corresponding to the diameter D before the previous printing process is acquired (step S350). When the remaining amount R before the previous printing process is obtained, the current remaining amount R (after the previous printing process) is calculated by subtracting the transport amount ΔR from the remaining amount R (step S360). Furthermore, the diameter D corresponding to the current remaining amount R is acquired based on the first correspondence relationship CR (step S370). As a result, the current diameter D of the roll body 3 can be estimated. Next, the width w of the recording paper 2 is measured by the paper width sensor 31, and the CPU 25 acquires the width w (step S380). Then, the CPU 25 acquires the second correspondence relationship CR2a, CR2b stored in the RAM 27 or the EEPROM 28 (step S390).

  FIG. 11 is a graph showing an example of the second correspondence relationship CR2a, CR2b. In the drawing, the horizontal axis indicates the diameter D of the roll body 3, and the vertical axis indicates the static loads Vlo and Vhi per unit width at each diameter D. As shown in the figure, the diameter D and the static loads Nlo and Nhi have a parabolic relationship. The second correspondence relationship CR2a, CR2b measures the diameter D of the roll body 3 sequentially while transporting the recording paper 2 from the roll body 3 at the low speed Vlo and the high speed Vhi, and the static loads Nlo, Nhi at the time of transport at each diameter D Can be obtained by preliminary investigation. Since the static loads Vlo and Vhi can be considered to be an amount proportional to the width w of the recording paper 2, by dividing the measured static loads Nlo and Nhi by the width w of the recording paper 2 at the preliminary survey, Static loads Nlo and Nhi per unit width can be obtained.

  As shown in FIG. 11, as the diameter D of the roll body 3 decreases, the static loads Nlo and Nhi per unit width also monotonously decrease. This is because as the recording paper 2 is unwound, the weight of the roll body 3 becomes lighter and the frictional resistance applied to the rotation of the roll body 3 is reduced. Since the current diameter D is obtained in step S360, the static loads Nlo and Nhi per unit width corresponding to the diameter D are acquired with reference to the second correspondence relationships CR2a and CR2b (step S400). Further, the static loads Nlo and Nhi of the entire width of the recording sheet 2 are calculated by multiplying the static loads Nlo and Nhi by the width w measured in step S380 (step S410).

  When the static loads Nlo and Nhi can be calculated, the current diameter D of the roll body 3 and the static loads Nlo and Nhi are updated and stored in the EEPROM 28. In this way, in the estimation process, the current diameter D and static loads Nlo and Nhi of the roll body 3 can be acquired without performing conveyance only for measurement, and time loss and paper loss can be suppressed. it can. When the next printing is executed, the estimation process may be repeated. In the present embodiment, the estimation process is executed for each printing process. However, the diameter D of the roll body 3 and the static loads Nlo and Nhi may be acquired based on the conveyance amount ΔR that increases as needed during printing. Is possible. The diameter D of the roll body 3 and the static loads Nlo and Nhi thus obtained can be used as follows, for example.

(Usage example 1 of diameter D)
In the printing process, the diameter D and the static loads Nlo and Nhi may be used in order to make the tension acting on the recording paper 2 constant. First, according to the static loads Nlo and Nhi, the static load N generated around the rotation axis of the roll body 3 at an arbitrary conveyance speed V can be calculated from the relationship shown in FIG. Further, since the static load N corresponds to the rotational resistance around the rotation axis of the roll body 3, the static load N and the static load N are in a state where the roll body 3 rotates against the static load N and the recording paper 2 is conveyed. The tension that balances the moment acts on the recording paper 2 on the outer peripheral surface of the roll body 3. On the other hand, in order to apply an ideal tension to the recording paper 2, it is necessary to adjust the torque acting around the rotation axis of the roll body 3 so as to balance the moment generated by the tension. That is, the torque may be adjusted so that the moment is balanced from the static load N in a state where the roll body motor 13 is not driven by positively generating torque by driving the roll body motor 13. The magnitude of the torque to be generated by driving the roll motor 13 can be calculated from the balance of the moments, but the moment can be calculated using the diameter D.

(Usage example 2 of diameter D)
When the conveyance direction of the recording paper 2 is skewed (so-called skew is generated), the roll motor 13 is reversed and the recording paper 2 is wound around the roll body 3 to eliminate the skew. be able to. In this case, the winding amount of the recording paper 2 is determined based on the rotation amount of the roll motor 13 detected by the rotary encoder 17. However, the winding amount of the recording paper 2 with respect to the rotation amount of the roll body motor 13 varies depending on the diameter of the roll body 3. That is, even when the rotation amount is the same, when the diameter of the roll body 3 is larger (that is, when the winding amount of the recording paper 2 is larger), the diameter of the roll body 3 is smaller (that is, when the recording paper 2 is wound). The amount of winding is larger than when the amount is small. On the other hand, in order to eliminate the skew feeding, it is necessary to wind the recording paper 2 having a certain length around the roll body 3, but depending on the detection of only the rotation amount of the roll body motor 13, the winding amount of the recording paper 2 is increased. Cannot be determined accurately.

  Therefore, if the winding amount of the recording paper 2 is determined only by the rotation amount of the roll body motor 13, when the diameter of the roll body 3 is small, the winding amount is small and the skew cannot be eliminated. On the contrary, when the diameter of the roll body 3 is large, the winding amount becomes large, and the recording paper 2 comes off the paper feed roller 15 upward. Accordingly, by setting the rotation amount of the roll body motor 13 in accordance with the diameter of the roll body 3, the winding amount of the recording paper 2 by the roll body 3 can be made appropriate.

(Usage example 3 of diameter D)
Prior to the start of the recording operation, the leading end of the recording paper 2 is positioned at a predetermined position with respect to the recording head 19 so that the recording is started from a predetermined position with respect to the leading end (lower end) of the recording paper 2. Align. As to whether or not the leading end of the recording paper 2 is at a predetermined position, for example, a configuration of detecting by an optical sensor is adopted. For this detection, in advance, the user reverses the roll body 3 with the recording paper 2 mounted on the printer 1 so that the leading end of the recording paper 2 is sufficiently below the predetermined position, and the recording paper 2 is moved upward. Transport to. Then, the rotation of the roll body 3 is stopped at the position where the optical sensor detects the leading end of the recording paper 2, thereby positioning the leading end of the recording paper 2 at a predetermined position.

  By the way, when the recording paper 2 is transported upward, the recording paper 2 needs to be transported upward at an appropriate speed in order to accurately detect the position of the tip portion by the optical sensor. Therefore, by setting the rotational speed of the roll motor 13 according to the diameter of the roll body 3, the winding speed (conveying speed) of the recording paper 2 by the roll body 3 can be made appropriate.

(Second Embodiment)
Next, a second embodiment of the present invention will be described with reference to FIG. 12, FIG. 13, and FIG. In the following description, the same components as those described in the first embodiment are denoted by the same reference numerals, and the description thereof is omitted. Further, the electrical configuration is a configuration in which the rotary encoder 18 in the first embodiment shown in FIG.

  In the first embodiment described above, the recording paper 2 is conveyed downward by driving the paper feed motor 14 and rotating the paper feed roller 15, and the roll body via the roll body 3 and the gear train 12 by this conveyance. The diameter of the roll body 3 is obtained by rotating the motor 13 and detecting the rotation amounts of the paper feed motor 14 and the roll body motor 13. In contrast, in the second embodiment, a conveyance detection roller 29 is provided as a driven roller that freely rotates following the conveyance of the recording paper 2, and the rotation axis of the conveyance detection roller 29 is provided on the rotation axis of the conveyance detection roller 29. A rotary encoder 30 for detecting the rotation amount is attached as a driven roller rotation amount detection means.

  When the roll body 3 is reversed and the recording paper 2 is rewound onto the roll body 3, the conveyance detection roller 29 is rotated by the recording paper 2 conveyed upward by this rewinding. Therefore, in the second embodiment, the rotation amount of the conveyance detection roller 29 that rotates following the conveyance upward of the recording paper 2 and the rotation amount of the roll body motor 13 that reversely rotates the roll body 3 are detected. The diameter of the roll body 3 is obtained from these rotation amounts.

  FIG. 12 is a flowchart showing the operation of the printer 1 when measuring the diameter of the roll body 3 in the second embodiment. FIG. 13 shows the conveyance of the recording paper 2 by the roll body 3 and the conveyance detection roller. It is a figure which shows the relationship with rotation of 29, etc. FIG. 14 is a graph showing the count amounts of the rotary encoders 17 and 30 when the diameter of the roll body 3 is measured. That is, FIG. 14 shows changes in the rotation amounts of the roll body motor 13 and the conveyance detection roller 29.

  As shown in FIG. 13, the conveyance detection roller 29 is disposed between the roll body 3 and the paper feed roller 15. The conveyance detection roller 29 is pressed against the conveyance detection roller 29 and rotated following the conveyance detection roller 29. A driven roller 32 is provided. That is, the recording sheet 2 passes between the conveyance detection roller 29 and the driven roller 32 and is passed through the paper feed roller 15.

(Printer operation)
The operation of the printer 1 when measuring the diameter of the roll body 3 in the printer 1 will be described with reference to FIGS.

  Prior to the execution of the measurement processing, the driven roller 16 is separated from the recording paper 2 by a user operation or an automatic operation of the printer 1, and the recording paper 2 is moved to the conveyance detection roller 29 and the driven roller 32. It is set as the state pinched by (Nip state). Measurement processing is performed under such a state.

  First, a slack eliminating operation for eliminating the slack of the recording paper 2 between the paper feed roller 15 and the roll body 3 is performed (step S10). In loosening elimination (step S10), the roll body motor 13 is driven so as to reverse the roll body 3 in the direction in which the recording paper 2 is conveyed upward. Then, it is determined whether or not the recording paper 2 is slack between the roll body 3 and the conveyance detection roller 29 (step S20). If it is determined that there is slack (Yes in step S20), the roll body 3 is reversed. If it is determined that there is no slack (No in step S20), the drive is stopped (step S30). The presence or absence of slack in the recording paper 2 between the roll body 3 and the conveyance detection roller 29 is determined based on, for example, the duty ratio of PWM voltage control in the voltage applied to the conveyance detection roller 29.

  When it is determined that there is no slack in the recording paper 2 between the roll body 3 and the conveyance detection roller 29 (Yes in step S20), the roll detection is continued after the conveyance detection roller 29 is stopped (step S30). The conveyance detection roller 29 is driven for a predetermined time, for example, 5 seconds so as to reverse the body 3 (step S40). The recording paper 2 is transported upward by the rotation of the roll body 3, and the transport detection roller 29 rotates in the reverse direction as the recording paper 2 is transported.

  Along with the start of driving of the conveyance detection roller 29, the rotary encoders 17 and 29 start detecting the rotation amounts of the conveyance detection roller 29 and the conveyance detection roller 29 (step S50). That is, in FIG. 14, detection of the rotation amounts of the roll body motor 13 and the conveyance detection roller 29 is started from the detection start time B1. In the graph of FIG. 14, the horizontal axis indicates the elapsed time from the start of driving the roll motor 13, and the vertical axis indicates the amount of rotation of the rotary encoders 17 and 29. At the detection start time B1, the count amount by the rotary encoders 17 and 29 is zero. The graph line (3) indicates the count amount by the rotary encoder 17, and the graph line (4) indicates the count amount by the rotary encoder 18. As can be seen from the graph of FIG. 14, while the drive of the roll motor 13 is continued, the count amounts of the rotary encoders 17 and 29 increase with the passage of time.

  When the roll body motor 13 is driven for a predetermined time (Yes in step S60), the drive of the roll body motor 13 is stopped (step S70). In conjunction with the stop of the driving of the roll motor 13, first, the count amount of the rotary encoder 18 is counted (step S80). For example, in the graph of FIG. 14, the count amount of the rotary encoder 17 at the driving stop time B2 of the roll motor 13 is measured as Cr2. Subsequent to counting the count amount of the rotary encoder 18, a predetermined time t, for example, 0.1 second is set (step S90), and the count amount of the rotary encoder 30 is counted (step S100). For example, in the graph of FIG. 7, the count amount at this time is measured as Cc.

  The recording paper 2 itself has some elasticity, and tension is applied to the recording paper 2 between the roll body 3 and the conveyance detection roller 29. Therefore, even if the drive of the roll motor 13 is stopped and the rotation of the conveyance detection roller 29 is stopped, the conveyance detection roller 29 is slightly rotated by the influence of the elastic force of the recording paper 2 and is conveyed by being dragged by this. The detection roller 29 may also rotate. Therefore, after the drive of the roll motor 13 is stopped, the count amount of the rotary encoder 17 is counted after a predetermined time in anticipation that the rotation of the conveyance detection roller 29 is completely stopped. Thereby, the measurement accuracy of the rotation amount of the roll body 3 corresponding to the conveyance amount of the recording paper 2 can be increased.

Subsequently, the diameter of the roll body 3 is calculated based on the measured rotation amount Ch of the conveyance detection roller 29 and the rotation amount Cr2 of the roll body motor 13 (step S110). This calculation can be performed based on the following equation.
Lh × (Ch / Rh) = D × π × (Cr2 / Rr) (3)
D = (Lh × (Ch / Rh)) / (π × (Cr2 / Rr)) (4)
Lh: the outer peripheral length of the paper feed roller 15.
Ch: a count amount of the rotary encoder 30.
Rh: Count amount of the rotary encoder 30 when the conveyance detection roller 29 makes one rotation.
D: The diameter of the roll body.
π: Pi ratio.
Cr2 is the count amount of the rotary encoder 17.
Rr: the count amount of the rotary encoder 17 of the conveyance detection roller 29 when the roll body 3 is rotated once, and the reduction ratio of the gear train 12 is set to the count amount of the rotary encoder 17 corresponding to one rotation of the conveyance detection roller 29. Multiplyed value.
Cr2 and Ch are measured values, and Lh, Rh, and Rr are known values that are measured in advance.

  The left side of Expression (3) indicates the amount of rotation on the outer periphery of the conveyance detection roller 29 when the conveyance detection roller 29 rotates the count amount Ch, that is, when the conveyance detection roller 29 rotates Ch / Rh. That is, if there is no slip between the conveyance detection roller 29 and the recording paper 2, the left side of Equation (3) is equal to the conveyance amount of the recording paper 2. The right side of Expression (3) indicates the amount of rotation at the outer periphery of the roll body 3 when the roll body motor 13 rotates by the count amount Cr2, that is, when the roll body 3 rotates by Cr2 / Rr. That is, if there is no slip between the roll body 3 and the recording paper 2, the right side of Equation (3) is also equal to the transport amount of the recording paper 2. And the diameter D of the roll body 3 is computable based on Formula (4) which deform | transformed Formula (3).

  In the first embodiment described above, the recording paper 2 is transported by the paper feed roller 15, and the transport amount is calculated based on the rotation amount of the paper feed roller 15, that is, the rotation amount of the paper feed motor 14. The paper feed roller 15 needs to transport the recording paper 2 against the rotational load of the roll body motor 13 connected to the heavy roll body 3 via the gear train 12 having a high reduction ratio. For this reason, slippage tends to occur between the paper feed roller 15 and the recording paper 2. Also, a large tension is generated on the recording paper 2. Therefore, there is a possibility that the conveyance amount of the recording paper 2 cannot be measured accurately.

  On the other hand, the conveyance detection roller 29 is a roller that freely rotates with respect to the conveyance (movement) of the recording paper 2. Therefore, the occurrence of slippage between the conveyance detection roller 29 and the recording paper 2 can be suppressed, the accuracy of measurement of the conveyance amount of the recording paper 2 can be improved, and consequently the diameter of the roll body 3 can be measured. Accuracy can be improved. Instead of detecting the rotation amount of the conveyance detection roller 29, the rotation amount of the driven roller 16 or the driven roller 32 may be detected.

  In the above-described embodiment, the printer 1 has been described as an ink jet printer that ejects ink. However, the present invention is not limited to this, and a liquid material in which particles of a functional material are dispersed, a flow material such as a gel, and a fluid are used. A solid that can be ejected may be ejected from a recording head (ejection head). Further, the printing apparatus is not limited to one that ejects ink or liquid, and the printing apparatus can be configured as a thermal printer that records on thermal paper, or an impact type printer that uses an ink ribbon or the like. In addition to the recording paper 2, the recording medium may be a cloth body or a sheet-like resin body.

  Further, a plurality of first and second correspondence relationships CR1, CR2a, and CR2b may be prepared depending on the type of each recording paper 2 as well as plain paper. For example, when the user designates the paper type, the first and second correspondences CR1, CR2a, and CR2b corresponding to the designated type may be read and referred to. In this way, printing with little loss can be realized for all types of recording paper 2.

1 is an external view illustrating an external configuration of a printer according to a first embodiment of the present invention. FIG. 2 is a configuration diagram illustrating a configuration of a printer. 2 is a circuit block diagram illustrating an electrical configuration of the printer. FIG. 3 is a flowchart illustrating an operation of a printer. It is a flowchart which shows a measurement process. It is a figure which shows the relationship between conveyance of the recording paper by a paper feed roller, and rotation of a roll body. It is a graph which shows the change of the count amount of a rotary encoder. It is a graph which shows the relationship between a conveyance speed and a static load. It is a flowchart which shows an estimation process. It is a graph which shows the 1st correspondence. It is a graph which shows the 2nd correspondence. 6 is a flowchart illustrating an operation of a printer according to a second embodiment of the present invention. It is a figure which shows the relationship between conveyance of the recording paper by the paper feed roller of the printer which concerns on the 2nd Embodiment of this invention, and rotation of a roll body. It is a graph which shows the change of the count amount of the rotary encoder of the printer which concerns on the 2nd Embodiment of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Printer (printing apparatus), 2 ... Recording paper (recording medium), 3 ... Roll body, 17 ... Rotary encoder, 18, 30 ... Rotary encoder, 25 ... CPU

Claims (8)

In a printing method in which a roll body around which a belt-like recording medium is wound is mounted, and recording is performed on the recording medium that is wound and conveyed from the roll body,
A printing method, wherein the recording medium is conveyed from the roll body, and the diameter of the roll body is measured based on a conveyance amount of the recording medium and a rotation amount of the roll body at that time. Storing the correspondence between the remaining amount of the recording medium in the roll body and the diameter of the roll body as a first correspondence;
Obtaining a remaining amount of the recording medium based on a conveyance amount of the recording medium conveyed during printing, and estimating a diameter of the roll body after printing based on the remaining amount and the first correspondence relationship; The printing method according to claim 1.   The printing method according to claim 1, wherein the transport amount is based on a rotation amount of a paper feed roller that transports the recording medium.   The printing method according to claim 1, wherein the conveyance amount is based on a rotation amount of a driven roller that rotates following the conveyance of the recording medium. The storage means stores a correspondence relationship between a diameter of the roll body and a static load necessary for rotating the roll body as a second correspondence relationship,
The printing method according to any one of claims 1 to 4, wherein the acquisition unit acquires a static load based on the diameter of the roll body and the second correspondence relationship.   The printing method according to claim 5, wherein the first correspondence relationship and the second correspondence relationship correspond to a type of the recording medium.   6. The static load after use is acquired based on the width, the diameter, and the second correspondence relationship by measuring a width in a direction perpendicular to the conveyance direction of the recording medium. 7. The printing method according to any one of 6. In a printing apparatus that is mounted with a roll body around which a belt-like recording medium is wound and performs recording on the recording medium that is wound and conveyed from the roll body,
Printing comprising: conveying means for conveying the recording medium from the roll body, and measuring a diameter of the roll body based on a conveyance amount of the recording medium at that time and a rotation amount of the roll body apparatus.

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