JP2013230899A - Recording apparatus and recording method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily and precisely detect an end edge of a roll sheet and to convey the roll sheet in conformity with the state of the end edge.SOLUTION: A recording apparatus includes a control part controlling a roll driving means for rotating a roll shaft holding a roll sheet, a rotation amount measuring means for measuring a rotation amount of the roll shaft, a conveying means for drawing and conveying the roll sheet, and a near-end edge detecting means for determining whether or not a winding number of the roll sheet is small. The control part causes the roll sheet to be subjected to pitch conveyance by a predetermined conveyance amount after detecting that the winding number of the roll sheet is small, causes a rotation amount of the rotated roll shaft to be measured, causes the roll shaft to be rotated in a feeding direction of the roll sheet when a ratio of the rotation amount of the roll shaft to the conveyance amount of the roll sheet at that time is equal to or lower than a first predetermined value, causes recording processing to be stopped when the rotation amount of the roll shaft is lower than a second predetermined value, and causes the recording processing to be continued when it is equal to or more than the second predetermined value.

Description

  The present invention relates to a recording apparatus and a recording method including repeating pitch conveyance for drawing a roll sheet wound in a roll shape.

  In a recording apparatus that records on roll paper, for example, an ink jet recording apparatus, it is important to accurately detect the end of the roll paper in order to effectively use the roll paper to the end. The roll paper here is a roll of long paper wound around a core paper core. There are several forms for starting the winding of the paper around the paper tube. In one form, the end of the paper is firmly fixed to the paper tube with an adhesive. In another form, no adhesive is used and the paper is simply wound on a paper tube. Hereinafter, the position where the paper starts to be wound around the paper tube is expressed as the end of the roll paper.

  In an ink jet recording apparatus, a sheet is pulled out from such a roll sheet, and an image is recorded on the pulled sheet. If this operation is repeated, the remaining amount of roll paper decreases, reaches the end of the roll paper, and the number of rolls of roll paper decreases. As described above, when the end of the roll paper is bonded to the paper tube, when the remaining amount of the roll paper is exhausted, the shaft around which the roll paper is wound cannot be rotated, and the paper cannot be conveyed (hereinafter, referred to as “roll paper”). Sometimes referred to as a strong adhesion state.) When the end of the roll paper is not adhered to the paper tube, when the remaining amount of the roll paper runs out, the end of the roll paper becomes free and loosens. In addition to this, the roll paper is temporarily loosened, but the roll paper may be wound around the paper tube again as the roll paper is transported thereafter (hereinafter referred to as a rewinding state). Sometimes.).

  In the case of the strong adhesion state, the roll paper cannot be pulled out any further, so that the paper cannot be conveyed and recording is continued at that position, and a normal image cannot be obtained. Therefore, it is necessary to stop recording immediately. On the other hand, when the roll paper is slack, the roll paper can be further pulled out, so that the recording operation can be continued. In the rewinding state, the looseness of the roll paper is eliminated as the roll paper is conveyed. This state is difficult to distinguish from a strong adhesive state.

  Patent Document 1 describes a method for detecting the end of a roll paper in order to determine the state of the end of the roll paper and use the roll paper effectively. The first method (detection method 1) is a method of detecting the state of the end of the roll paper by reducing the current value of the transport motor for transporting the roll paper when the end of the roll paper is reached. In the detection method 1, a shortage of rotation of the transport motor due to the fact that the paper cannot be transported in the strong adhesion state is detected. When the second method (detection method 2) is near the end of the roll paper, the amount of rotation of the roll shaft (rotary shaft) that holds the roll paper is monitored, and if it is determined that the rotation of the roll shaft accompanying conveyance has been lost. In this method, the roll shaft is rotated in the rewind direction. If the roll shaft does not rotate even though the roll paper is to be conveyed, it is determined that the roll paper is in a strong adhesive state or a re-wound state. Further, when a predetermined amount of paper is conveyed and the roll shaft rotates, it is determined that the paper is rewound.

JP 2009-269713 A

  In the detection method 1 described above, the end of the roll paper is detected by reducing the drive margin of the carry motor. However, there are variations in the carrying load due to the difference in the type of paper, the carrying accuracy, and the detection of the strong adhesion state. Adjustment is difficult. In the detection method 2, in order to distinguish between the strong adhesion state and the rewinding state, it is necessary to convey a predetermined amount of roll paper, and it is necessary to temporarily interrupt the image recording operation. It becomes complicated.

  The present invention has been made in view of the above problems, and an object of the present invention is to easily and accurately detect the end of a roll sheet and to convey the roll sheet according to the state of the end of the roll sheet. It is to provide a recording apparatus and a recording method that can be used.

  A recording apparatus according to an aspect of the present invention is a recording apparatus that performs a recording process that repeats pitch conveyance for drawing a roll sheet wound in a roll shape by a predetermined amount, and a roll shaft that rotatably holds the roll sheet; A roll driving unit that rotates the roll shaft, a rotation amount measuring unit that measures the rotation amount of the roll shaft, a transport unit that pulls and conveys the roll sheet from the roll shaft, and the number of windings of the roll sheet is small. The near end detection means for determining whether or not the roll sheet has been made, and whether or not the number of windings of the roll sheet has been decreased, and after detecting that the number of windings of the roll sheet has decreased, the roll sheet Was transported by the predetermined transport amount, and the rotation amount of the roll shaft rotated by the pitch transport was measured, and pulled out by the pitch transport. When the ratio of the rotation amount of the roll shaft to the transport amount of the roll sheet is equal to or less than a first predetermined value, the roll shaft is rotated in the direction of feeding the roll sheet, and the rotation amount of the roll shaft is The roll driving means to stop the recording process when it is less than a second predetermined value, and to continue the recording process when the rotation amount of the roll shaft is equal to or greater than a second predetermined value; A control unit for controlling the rotation amount measuring unit, the conveying unit, and the terminal vicinity detecting unit.

A recording method according to an aspect of the present invention is a recording method including a recording process in which pitch conveyance is repeatedly performed to pull out the roll sheet by a predetermined amount from a roll shaft that rotatably holds a roll sheet wound in a roll shape, A step of determining whether or not the number of windings of the roll sheet has decreased, and a transporting step of pitch transporting the roll sheet by a predetermined transport amount after detecting that the number of windings of the roll sheet has decreased. A ratio of the rotation amount of the roll shaft with respect to the conveyance amount of the roll sheet pulled out in the conveyance step is measured according to a first predetermined value. A roll axis rotation step for rotating the roll axis in the direction of feeding out the roll sheet,
When the rotation amount of the roll shaft rotated in the roll shaft rotation step is less than a second predetermined value, the step of stopping the recording process; and the rotation amount of the roll shaft rotated in the roll shaft rotation step Continuing the recording process when is equal to or greater than a second predetermined value.

  According to the recording apparatus and the recording method of the present invention, the end of the roll sheet can be detected easily and accurately, and the roll sheet can be conveyed in accordance with the state of the end of the roll sheet.

It is a perspective view which shows the attachment part to which roll paper is attached. FIG. 2 is a cross-sectional view illustrating a schematic configuration of a printer as a recording apparatus. It is a schematic diagram of a roll axis drive system and an LF roller drive system. It is a schematic diagram which shows three states in the end vicinity of roll paper. It is a schematic diagram which shows a state when rotating a roll axis | shaft to a conveyance direction with respect to the three states shown in FIG. It is a block diagram which shows the control system of a printer. It is a flowchart which shows the operation | movement procedure in a 1st Example. It is a flowchart which shows the operation | movement procedure in a 2nd Example.

  Embodiments of the present invention will be described below with reference to the drawings.

[First embodiment]
FIG. 1 is a perspective view showing a configuration of an attachment portion to which roll paper is attached. FIG. 2 is a schematic cross-sectional view of an ink jet printer which is an example of a recording apparatus including a paper feeding unit according to an embodiment of the present invention. An ink jet printer performs recording on a recording medium by ejecting ink onto the recording medium.

  For the recording medium of this embodiment, roll paper R, which is continuous paper wound in a roll shape, is used. A roll sheet in which a continuous sheet other than paper is wound in a roll shape can also be used. As shown in FIG. 1, a spool shaft (roll shaft) 32 is passed through a paper tube S at the winding center of the roll paper R. The loading portion 31 of the reference-side roll paper holder 30 disposed on the spool shaft 32 bites into the inner wall of the paper tube S by the elastic force in the radial direction. As a result, the roll paper R is held on the spool shaft 32, and the roll paper R is rotatably fixed together with the spool shaft 32. Further, the non-reference-side roll paper holder 34 is passed through the spool shaft 32 from the reverse side of the reference-side roll paper holder 30 so as to sandwich the roll paper R, and set on the paper tube S. A spool gear 33 for receiving a rotational driving force from the printer body is attached to the non-reference side of the spool shaft 32.

  Next, a printer to which the roll paper holders 30 and 34 holding the roll paper R are attached will be described with reference to FIG. The spool shaft 32 to which the roll paper R is attached is rotatably supported by the printer 1. The paper drawn out from the roll paper R is fed out to the conveyance path, and the leading edge of the paper passes through the reflection type paper detection sensor 41. This reflection type paper detection sensor 41 detects the presence or absence of paper. When the trailing edge of the paper passes the paper detection sensor 41, the state is notified to the outside. The paper drawn from the roll paper R reaches the nip portion of the LF roller pair 9, 10. The LF roller pair includes an LF roller (conveying roller) 9 as a conveying unit that pulls out and conveys the roll paper, and a roller 10 that rotates following the LF roller 9. The pair of LF rollers 9 and 10 rotate while sandwiching a sheet, and convey the sheet toward the platen 19.

  Immediately above the platen 19 is provided a carrier 12 that reciprocally scans in the direction perpendicular to the paper surface (main scanning direction) in FIG. A recording head 11 is mounted on the carrier 12. While the carrier 12 moves the recording head 11 in the main scanning direction, the recording head 11 ejects ink onto a sheet on the platen 19. Thereby, one line can be recorded on the paper. After the recording of one line is completed, the paper is pulled out from the roll paper R by a predetermined amount by the LF roller pairs 9 and 10 (pitch conveyance). By repeating this pitch conveyance and main scanning of the carrier 12 and the recording head 11, desired recording is performed on the paper drawn from the roll paper.

  More specifically, both ends are fixed to the frame of the printer 1, and the carrier 12 is supported by guide shafts 16 arranged in parallel to each other. The carrier 12 is slidably supported along a guide rail (not shown). Then, ink is ejected from the recording head 11 while the carrier 12 is reciprocated toward the roll paper R conveyed to the image recording unit 2 which is an area where the platen 19, the carrier 12 and the recording head 11 are provided. As a result, an image is recorded on the paper drawn from the roll paper R. After the image recording unit 2 records an image for one line by scanning for one line by the forward or backward operation of the carrier 12, the roll paper R is fed by a pair of LF rollers 9 and 10 in the transport direction by a predetermined pitch. Then, the carrier 12 is scanned again to record an image for the next line. By repeating this, an image of the entire page sentence is recorded on the paper. Here, when the roll paper is pitch-conveyed by the pair of LF rollers 9 and 10, since the brake is applied to the spool shaft 32 with a predetermined force, the roll paper is stretched with a predetermined tension (back tension). The pitch is conveyed.

  The recorded roll paper portion is conveyed onto the paper discharge tray 22. When the image recording is completed, the paper drawn from the roll paper is conveyed to a predetermined cutting position by the LF roller pair 9 and 10 and cut by the cutter 21. As a result, the recorded roll paper portion is separated and discharged to the outside of the printer 1.

  FIG. 3 shows an LF roller driving system that drives the LF roller pair 9 and 10 and a roll shaft driving system that rotationally drives the spool shaft 32 that holds the roll paper. The LF roller drive system includes an LF motor 8 and LF transmission gears 55 and 56. The driving force of the LF motor 8 is transmitted to the LF roller 9 through the LF transmission gears 55 and 56. A circular LF encoder film 54 having radial slits is fixed to the LF roller 9. The LF encoder sensor 5 detects the amount of rotation of the LF roller 9 and emits a pulse along with the amount of rotation. Normally, the LF encoder sensor 5 emits 60 pulses when the LF roller 9 transports 1 mm of the paper drawn from the roll paper R.

  The roll shaft drive system transmits a rotational force from the roll motor (roll drive means) 40 to the spool gear 33 of the roll shaft via the roll transmission gear 36, the gear 37, and the gear 38. A torque limiter that applies a rotational load to the gear is provided between the roll transmission gear 38 and the spool gear 33. Accordingly, when the roll paper R is conveyed by the LF roller 9 with the current of the roll motor 40 turned off, a back tension is applied to the roll paper R. The roll transmission gear 37 is provided with a roll encoder film 53 and a roll encoder sensor (rotation amount measuring means) 39. As with the LF encoder sensor 5, the roll encoder sensor 39 emits a pulse with the amount of rotation of the roll shaft 32. Thereby, the roll encoder sensor 39 can measure the rotation amount (rotation angle) of the roll shaft 32, that is, the roll paper.

  When the paper pulled out from the roll paper is conveyed by a predetermined amount, the rotation amount of the roll shaft 32 varies depending on the diameter of the roll paper R (roll diameter). Therefore, when a predetermined amount of the paper drawn from the roll paper R by the LF roller 9 is conveyed, the number of pulses generated by the roll encoder sensor 39 changes according to the diameter of the roll paper R (roll diameter). The maximum roll diameter that can be installed in the printer 1 is φ180 mm. The minimum roll diameter is the same as the outer diameter of the paper tube S, and is φ60 mm as an example. The roll diameter and the number of generated pulses are inversely related. When the maximum diameter is 180 mm, when the sheet is conveyed 1 mm by the LF roller 9, the roll encoder sensor 39 emits 6 pulses, and when φ72 mm, 15 pulses are emitted. In the vicinity of the minimum φ60 mm, the roll encoder sensor 39 emits 18 pulses. Therefore, normally, while using roll paper, the number of pulses of the roll encoder sensor 39 when the roll sheet is pulled out by a predetermined conveyance amount increases.

  When the paper is pitched by 10 mm by the LF roller 9, the LF encoder sensor 5 emits 600 pulses, whereas the roll encoder sensor 39 is 60 pulses when the diameter of the roll paper is φ180 mm, 150 pulses when φ72 mm, and 180 pulses when φ60 mm. Emit a pulse. That is, the ratio of the pulse number of the roll encoder sensor 39 to the pulse number of the LF encoder sensor 5 is 10% when the roll paper diameter is φ180 mm, 25% when φ72 mm, and 30% when φ60 mm.

  Normally, as the sheet is conveyed by the LF roller 9 as described above, the roll shaft 32 to which the roll sheet R is attached also rotates. However, in the vicinity of the end of the roll paper R, that is, when the number of roll paper rolls is small, the following three states can exist. These three states will be described with reference to FIG. The first state is a state where the end of the roll paper R is firmly adhered to the paper tube S as shown in FIG. In this state, the paper tube S does not rotate even if the LF roller pair 9, 10 tries to carry the paper in the direction of the arrow. Therefore, the paper is slipped by the pair of LF rollers 9, 10, and the paper cannot be conveyed. Therefore, if the recording operation is continued as it is, the ink is applied in the same place on the paper, and not only a necessary image cannot be obtained, but the ink on the paper becomes excessive, and the inside of the printer 1 may be stained. In this case, it is desirable to detect an anomaly as soon as possible and to stop the sheet transport operation and the recording process.

  In the second state, as shown in FIG. 4B, the end of the roll paper R is wound around the paper tube S but is not bonded. In this state, when the sheet is continuously conveyed in the arrow direction by the pair of LF rollers 9 and 10, the end of the roll sheet R is separated from the sheet tube S. As a result, the rotation of the paper tube S is stopped, and the rotation of a roll shaft (not shown) to which the paper tube S is attached is also stopped. In this case, it is possible to continue the pitch conveyance and recording processing by the LF roller 9 until the paper detection sensor 41 provided upstream of the LF roller pair 9 and 10 detects the end of the roll paper R.

  As shown in FIG. 4C, the third state is a state that occurs rarely when the remaining number of rolls is about 5 from the end of the roll paper R before reaching the second state. This is a state in which the roll paper R is slightly loosened with respect to the paper tube S due to the roll paper rewinding operation after the completion of the paper cutting or the action of unwinding the paper itself. In this state, the rotation of the roll shaft is temporarily stopped or reduced with respect to the conveyance in the arrow direction by the LF roller pair 9 and 10. The state where the roll paper is loose and the rewinding state accompanying the conveyance by the LF roller 9 may be repeated about 2 to 3 times. Therefore, the roll paper back tension generated by the braking force applied to the roll shaft 32 may or may not be unstable.

  As the printer 1, in order to prevent the roll paper from being poorly conveyed by the printer 1 while using the roll paper without waste, and to obtain a proper image by suppressing fluctuations in the back tension, the above three states are detected correctly. It is necessary to perform an appropriate operation. The above three states are accompanied by a phenomenon that the number of pulses of the roll encoder sensor 39 decreases or a phenomenon that the roll encoder sensor 39 stops. Therefore, by detecting that the ratio of the pulse number of the roll encoder sensor 39 to the pulse number of the LF encoder sensor 5 is smaller than a predetermined value, it is possible to determine whether or not three states have occurred. Instead, it is determined whether or not three states have occurred by detecting that the number of pulses of the roll encoder sensor 39 has become smaller than a predetermined value for the conveyance of a predetermined amount of roll paper. May be.

  The ratio of the number of pulses in a normal state is 10% at the maximum roll diameter φ180 mm, and 30% at the minimum roll diameter φ60 mm. Therefore, for example, it is not necessary to detect whether or not three states have occurred until the end of the roll paper, that is, until the diameter of the roll paper reaches φ72 mm, that is, until the ratio of the number of pulses reaches 25%. . In this way, by detecting that the ratio of the number of pulses or the number of pulses of the roll encoder sensor 39 exceeds a preset third predetermined value, the number of rolls of roll paper has decreased, that is, the roll It is possible to detect near the end of the paper.

  After the ratio of the number of pulses once becomes 25% or more, it can be determined that the remaining amount of roll paper is low, and therefore it is determined whether or not the above three states have occurred. For example, when the ratio of the number of pulses once becomes 25% or more (a third predetermined value or more) and then decreases to a first predetermined value (for example, 23% or less), It may be determined that one of the states has been reached. Here, the first predetermined value is a value smaller than the third predetermined value. Alternatively, the ratio of the number of pulses for the past N times may be averaged, and it may be determined that one of the three states has been reached when the ratio of the number of pulses has decreased by 5% with respect to the average value.

  As described above, when the ratio of the rotation amount of the roll shaft to the conveyance amount of the roll paper drawn by the LF roller 9 is equal to or less than the first predetermined value, it is detected that one of the three states has occurred. can do. In this case, the roll shaft 32 is rotated in the transport direction, that is, the direction in which the roll paper R is sent out. The above three states when the roll shaft 32 is rotated in the transport direction will be described with reference to FIG.

  In the first state, the end of the roll paper R is firmly bonded to the paper tube S. Therefore, as shown in FIG. 5A, even if the roll shaft 32 is rotated in the transport direction, the roll shaft 32 cannot be immediately rotated, and the pulse of the roll encoder sensor 39 is stopped. Therefore, it can be determined that the state is the first state by detecting the number of pulses of the roll encoder sensor 39. As soon as the determination is made, the conveyance of the roll paper and the recording process are stopped, so that a failure of the printer 1 can be prevented.

  In the case of the second state, as shown in FIG. 5B, the roll paper R and the paper tube S are separated and are not bonded. Therefore, the roll shaft 32 can freely rotate. In the case of the third state, even when the roll paper R is wound again by the roll paper transported by the LF roller 9, the roll shaft 32 rotates in the transport direction as shown in FIG. The roll paper is forcibly loosened.

  Here, since the rear end of the roll paper R is slack in the second state and the third state, the back tension does not fluctuate. Until the trailing edge of the roll paper is detected by the paper detection sensor 41 upstream of the LF roller 9, it is possible to perform conveyance and recording processing by the LF roller 9, and the roll paper can be used without waste. Therefore, if at least the first state and the second or third state are distinguished according to the number of pulses of the roll encoder sensor 39, the conveyance failure in the printer 1 can be prevented and the roll paper can be used unnecessarily. it can. The operation of rotating the roll shaft 32 in the transport direction to distinguish each state can be performed at any timing, such as during the pitch transport by the LF roller 9 or during the recording operation by the recording head 11.

  FIG. 6 is a block diagram of a control system related to conveyance of roll paper, recording on the roll paper, and detection of the state of the roll paper. The control unit 101 mounted on the printer 1 is connected to the host computer 100 via an interface (not shown). Recording data and data related to recording are transferred from the host computer 100 to the printer 1. The control unit 101 performs processing such as color processing, reduction / enlargement processing, binarization, and the like on the print data transferred from the interface, and finally prints the print data developed into a dot pattern. Accumulate in memory. The control unit 101 receives signals from the LF encoder sensor 5, the roll encoder sensor 39, or the paper detection sensor 41, and drives the LF motor 8, the roll motor 40, the carrier motor 61, the cutter 21 and the like as necessary. . The carrier motor 61 is a motor that drives the carrier 12. The control unit 101 controls the roll motor 40, the roll encoder sensor 39, the LF roller 9, and the like so that the printer 1 executes a series of processes shown in FIGS.

  An example of a recording process for accurately detecting the roll state (the above three states) and effectively using the roll paper until the end of the roll paper will be described with reference to the flowchart of FIG.

<1-line printing (step S01)>
The roll paper R drawn to the recording position by the LF roller pair 9 and 10 in advance is scanned by the movement of the carrier 12 and the ink is ejected by the recording head 11, so that one line is placed on the roll paper R. A 10 mm wide image is printed.

<Pitch conveyance (step S02)>
The roll paper R is pitch transported by a pair of LF rollers 9, 10 at a predetermined transport amount, for example, 10 mm.

<Roll encoder, detected once more than 25% in the past (step S03)>
As described above, in the case of φ60 mm, which is the minimum value of the roll diameter of the roll paper, the ratio of the pulse number of the roll encoder sensor 39 to the pulse number of the LF encoder sensor 5 is 30%. That is, when the ratio of the number of pulses is 25%, it means that the roll paper is reduced to the number of windings that is very close to the end of the roll paper. Therefore, it is detected whether or not the ratio of the number of pulses has been at least once in the past 25% or more (third predetermined value or more). The process for determining whether or not the above condition has occurred is started. In the present embodiment, whether or not to start the process for determining whether or not the first to third states have occurred is determined when the ratio is 25% or more. What is necessary is just to determine suitably according to a recording device or roll paper.

<Roll encoder, 23% or less detected (step S04)>
It is detected whether the ratio of the number of pulses of the roll encoder sensor 39 to the number of pulses of the LF encoder sensor 5 has become 23% or less (below the first predetermined value). Taking into account the detection error of the number of pulses of the roll encoder sensor 39 and the variation in the behavior of the paper from the experiment, a value of 23% obtained by subtracting 2% from the ratio (25%) in step S03 was used as a criterion for judgment. . Note that the first predetermined value is not limited to 23% and may be determined as appropriate.

  When the ratio of the number of pulses becomes 23% or less, it is determined that the roll shaft is difficult to stop or rotate. As the diameter of the roll paper decreases, the number of pulses of the roll encoder sensor 39 continues to increase, and the rate of the number of pulses once exceeds 25%. However, the situation below 23% again means that the pulse count of the roll encoder sensor 39 is stagnant, and it can be said that the roll shaft is difficult to stop or rotate. This means that the roll paper is in any one of the first to third states. However, it is impossible to determine which state is based on this alone.

<Forward rotation of a predetermined amount of roll (roll shaft rotation step: step S05)>
Here, in order to determine whether the paper tube S and the roll paper R are in the first state where the roll shaft does not rotate because of the strong adhesion state, or the second and third states where the roll shaft is difficult to rotate, The roll shaft 32 is rotated in the transport direction by a predetermined amount, for example, 30 mm. In the first state, because of the strong adhesion state, as shown in FIG. 5 (A), the roll shaft 32 cannot rotate freely, and the number of pulses of the roll encoder sensor 39 is the thickness of the roll paper. It takes a value of 0 to 250 pulses depending on the hardness. Since the roll shaft can freely rotate in the second or third state, the number of pulses around 450 corresponding to the rotation amount of the roll shaft is detected. Here, 10% is expected as a detection error, and 405 pulses (second predetermined value) are set as a threshold value. However, the second predetermined value is not limited to 405 pulses, and may be determined as appropriate.

<Detection of roll encoder 405 pulses or more (step S06)>
When the number of pulses of the roll encoder sensor 39 is less than 405 pulses (less than a second predetermined value), it can be determined that the first state is a strong adhesion state. When 405 pulses or more (second predetermined value or more) is detected, it can be determined that the state is in the second or third state.

<Printing Canceled (Step S07)>
If the first state is determined, or if the trailing edge of the sheet is detected in the subsequent step S10, printing cannot be continued any further, so printing is stopped immediately, and a notifying means (not shown) is used. Encourage the user to process.

<One-line printing (step S08)>
If it is determined that the state is the second or third state, an image for one line is printed on the roll paper R being conveyed to a predetermined position in the same manner as in step S01.

<Pitch transport (step S09)>
The roll paper R is pitch-conveyed by a predetermined amount, for example, 10 mm by the pair of LF rollers 9 and 10.

<Paper trailing edge detection (step S10)>
The paper detection sensor 41 detects whether or not the roll paper R exists in the paper conveyance path. If roll paper R is detected, the recording process is continued. If not detected, it is determined that the trailing edge of the roll paper separated from the paper tube S has passed the paper detection sensor 41, and the recording process is stopped.

<End of print data (step S11)>
When the predetermined recording process is completed, the roll paper printing unit is cut out by the cutter 21, and the print standby state is resumed.

  As described above, in this embodiment, when the remaining amount of roll paper is low, the roll paper is rotated by a predetermined amount in the transport direction, and the actual rotation amount is detected. Depending on the actual rotation amount at this time, the end state of the roll paper is a strong adhesive state where the recording cannot be continued (first state), or a state where the recording can be continued other than the strong adhesive state (the second or third state). State) can be easily and accurately identified. Accordingly, the roll paper can be appropriately conveyed in accordance with the state of the end of the roll paper.

[Second Embodiment]
In the second embodiment, when it is determined that the recording can be continued (second or third state) other than the strong adhesion state and the recording process is continued, the roll paper is sent according to the state of the roll paper. The switching of the LF correction value at that time will be described. Here, the LF correction value is a correction value for correcting the rotation amount of the LF roller 9.

  When the roll paper R is set on the LF roller 9 in a slightly inclined state, the roll paper R is skewed when the long roll paper R is conveyed by the LF roller 9. At this time, the roll paper R may reach the outside of the recording range. Therefore, as described in the first embodiment, it is preferable to apply a back tension to the roll paper R by setting a torque limiter on the roll shaft 32 and applying a braking force to the roll shaft. By this back tension, the skew of the roll paper is suppressed. Since the back tension is applied in the direction opposite to the conveyance direction with respect to the conveyance of the roll paper R by the LF roller 9, the LF roller 9 slips on the roll paper when the LF roller 9 is conveyed, thereby causing a deviation in conveyance. is there. For this reason, in this embodiment, a certain amount of LF correction value is added to the rotation amount of the LF roller 9 so that the roll paper is conveyed by the original conveyance amount. For example, when the roll paper is conveyed 10 mm by the LF roller 9, a correction value for two pulses is added to 600 pulses of the LF encoder sensor 5 so that the conveyance amount of the roll paper is not shortened due to back tension. The roller 9 is rotated by 602 pulses. As a result, even if the LF roller 9 slides on the roll paper by two pulses, the roll paper can be fed by 10 mm, which is the original transport amount.

  Since the back tension is applied to the roll paper R in the state where the roll paper R is wound around the paper tube S, two pulses are applied as the LF correction value LH2 as described above. On the other hand, in the slack state, the back tension does not act on the roll paper R, so 0 is applied as the LF correction value LH1, and the LF correction value is unnecessary.

  Therefore, the rotation amount of the LF roller 9 is corrected with the LF correction value LH2 (= 2 pulses) until the paper detection sensor 41 detects the end of the roll paper R. It is not necessary to correct the amount of rotation of the LF roller 9 after the roll paper R is made slack by rotating the roll shaft forward. In this way, uniform conveyance accuracy can be obtained up to the end of the roll paper R.

  An example of a recording process including a procedure for adjusting the LF correction value according to the presence or absence of the back tension of the roll paper will be described with reference to the flowchart of FIG.

<LF Correction Value LH2 (Step S20)>
First, the LF correction value when the roll paper is conveyed by pitch conveyance (step S22) is set to LH2. The LF correction value LH2 is a correction value when the back tension is applied to the roll paper.

<1-line printing (step S21)>
The roll paper R, which has been transported to the recording position by the LF roller pair 9 and 10 in advance, is scanned by moving the carrier 12 and ejecting ink by the recording head 11, and the width of one line on the roll paper R is 10 mm. Print the image.

<Pitch conveyance (step S22)>
The roll paper is conveyed by a predetermined pitch, for example, 10 mm pitch by the LF roller pairs 9 and 10. Here, the rotation amount of the LF roller 9 is corrected with the LF correction value LH2, and the roll paper is conveyed by the conveyance amount as the target value.

<Roll encoder, detected once more than 25% in the past (step S23)>
Similar to the first embodiment, in the case of φ60 mm which is the minimum roll diameter, the ratio of the pulse number of the roll encoder sensor 39 to the pulse number of the LF encoder sensor 5 is 30%. That is, when the ratio of the number of pulses is 25%, it means that the roll paper has been reduced to the number of windings that is very close to the end. Therefore, processing for determining whether or not the state is in the first to third states is started at the time point when the ratio of the number of pulses is 25% or more is detected.

<Roll encoder, 23% or less detected (step S24)>
It is detected whether the ratio of the number of pulses of the roll encoder sensor 39 to the number of pulses of the LF encoder sensor 5 has become 23% or less. Taking into account the detection error of the number of pulses of the roll encoder sensor 39 and the variation in the behavior of the paper from the experiment, a value of 23% obtained by subtracting 2% from the ratio (25%) in step S23 is used as a criterion for judgment. . That is, when the ratio of the number of pulses becomes 23% or less, it is determined that the roll shaft is difficult to stop or rotate. As the diameter of the roll paper decreases, the number of pulses of the roll encoder sensor 39 continues to increase, and the rate of the number of pulses once exceeds 25%. However, the situation below 23% again means that the pulse count of the roll encoder sensor 39 is stagnant, and it can be said that the roll shaft is difficult to stop or rotate. This means that the roll paper is in any one of the first to third states, but it is not possible to determine which state is only by this.

<Forward rotation of a predetermined amount of roll (roll shaft rotation step: step S25)>
Here, in order to determine whether the paper tube S and the roll paper R are in the first state where the roll shaft does not rotate because of the strong adhesion state, or the second and third states where the roll shaft is difficult to rotate, The roll shaft is rotated forward by 30 mm in the transport direction. In the first state, since it is a strong adhesion state, as shown in FIG. 5A, the roll shaft cannot rotate freely, and the number of pulses of the roll encoder sensor 39 depends on the thickness of the roll paper, It takes a value of 0 to 250 pulses depending on the hardness. Since the roll shaft can freely rotate in the second or third state, the number of pulses around 450 corresponding to the rotation amount of the roll shaft is detected. Here, 10% is expected as a detection error, and 405 pulses are set as a threshold value.

<Detection of roll encoder 405 pulses or more (step S26)>
When the number of pulses of the roll encoder sensor 39 is less than 405 pulses, it can be determined that the first state is a strong adhesion state. When 405 pulses or more are detected, it can be determined that the state is in the second or third state.

<Cancel printing (step S27)>
If the first state is determined, or if the trailing edge of the sheet is detected in the subsequent step S33, the recording process cannot be continued any further, so the recording process is stopped promptly, and notifying means (not shown) To prompt the user for processing.

<LF Correction Value LH1 (Step S30)>
If the second or third state is determined, the LF correction value when the roll paper is conveyed in the subsequent pitch conveyance (step S32) is reset from LH2 to LH1. The LF correction value LH1 is a correction value when the back tension is not acting on the roll paper.

<One Line Recording (Step S31)>
Next, an image having a width of 10 mm is printed on the roll paper R for one line by scanning due to the movement of the carrier 12 and discharging the ink by the recording head 11.

<Pitch conveyance (step S32)>
The roll paper is conveyed by a predetermined amount of 10 mm by the pair of LF rollers 9 and 10. Here, the roll paper is conveyed according to the target value by correcting the rotation amount of the LF roller 9 with the LF correction value LH1.

<Paper end detection (step S33)>
During the recording operation, it is determined whether or not the end of the roll paper is detected by the paper detection sensor 41 after the end of the roll paper is separated from the paper tube while the roll paper is being conveyed by the pair of LF rollers 9 and 10. To do. If the end of the roll paper is detected, it is determined that the recording process cannot be continued, and the recording process is stopped.

<Roll predetermined amount normal rotation (step S34)>
The roll paper is rotated by a predetermined amount in the conveyance (forward rotation) direction. This predetermined amount is set to a value equal to or larger than the conveyance amount of the pitch conveyance by the LF roller 9 at the time of the recording process, so that the slack of the roll paper can be reliably ensured while the recording proceeds. Here, the normal rotation of the roll paper is executed in synchronism with the conveyance by the LF roller 9, but the timing of the normal rotation of the roll paper is slightly changed if the slack of the roll paper is surely secured. Also good. Further, forward rotation of the roll paper is intermittently executed in synchronization with the LF roller 9 that operates intermittently. However, it is not always necessary to synchronize, and the roll paper may be continuously forward rotated at a low speed with respect to the intermittently operating LF roller 9. In any case, the normal rotation speed and operation timing of the roll paper may be set as long as the slack can be always secured in the roll paper.

<End of print data (step S35)>
It is determined whether all the printing processes for the print data have been completed. If no print data remains, the recording process is stopped.

  As described above, in this embodiment, the roll paper is rotated in the conveyance direction to ensure that the roll paper is not slack, the back tension is not applied to the roll paper, and the LF correction value without back tension is adjusted. Thus, accurate roll paper can be conveyed.

  Note that a program for causing a recording apparatus such as a printer to execute the recording method as shown in FIG. 7 or 8 and a storage medium storing the program are also included in the scope of the present invention.

R Roll paper (roll sheet)
1 Printer (recording device)
9 LF roller (conveying means)
32 Spool shaft (roll shaft)
39 Roll encoder sensor (rotation amount measuring means)
40 Roll motor (roll drive means)
101 Control unit

Claims (15)

A recording apparatus that performs a recording process that repeats pitch conveyance for drawing a roll sheet wound in a roll shape by a predetermined amount,
A roll shaft for rotatably holding the roll sheet;
Roll driving means for rotating the roll shaft;
A rotation amount measuring means for measuring the rotation amount of the roll shaft;
Conveying means for pulling out and conveying the roll sheet from the roll shaft;
Near-end detection means for determining whether or not the number of windings of the roll sheet has decreased,
It is determined whether or not the number of windings of the roll sheet has decreased, and after detecting that the number of windings of the roll sheet has decreased, the roll sheet is pitch transported by a predetermined transport amount. When the rotation amount of the rotated roll shaft is measured, and the ratio of the rotation amount of the roll shaft to the transport amount of the roll sheet pulled out by the pitch transport is equal to or less than a first predetermined value, the roll The roll shaft is rotated in the sheet feeding direction, and the recording process is stopped when the rotation amount of the roll shaft is less than a second predetermined value, and the rotation amount of the roll shaft is equal to or greater than a second predetermined value. A control unit for controlling the roll driving unit, the rotation amount measuring unit, the conveying unit, and the end vicinity detecting unit so that the recording process is continued in the case of And that, the recording device. The recording apparatus according to claim 1,
A recording apparatus comprising recording means for recording on the drawn roll sheet during the pitch conveyance. The recording apparatus according to claim 1 or 2,
The vicinity of the end detection unit is configured to detect a rotation amount of the roll shaft measured by the rotation amount measurement unit with respect to a conveyance amount of the roll sheet pulled out when the roll sheet is pulled out by a predetermined amount by the conveyance unit. A recording apparatus that detects that the number of windings of the roll sheet has decreased by detecting that the ratio has become equal to or greater than a third predetermined value that is greater than the first predetermined value. The recording apparatus according to any one of claims 1 to 3,
The said control part is a recording device which rotates the said roll axis | shaft in the direction which sends out the said roll sheet after the said pitch conveyance after continuing the said recording process. The recording apparatus according to claim 4,
The amount of the roll sheet sent out by rotating the roll shaft in the direction to send out the roll sheet is equal to or more than the amount of the roll sheet conveyed by the conveying means in the pitch conveyance. . The recording apparatus according to claim 4 or 5, wherein
The transport means is a transport roller;
The controller controls the rotation amount of the conveyance roller in the pitch conveyance after continuing the recording process by a predetermined correction value than the rotation amount of the conveyance roller in the pitch conveyance before continuing the recording process. A recording device that makes it smaller. The recording apparatus according to claim 6,
The recording apparatus determines the predetermined correction value to be a rotation amount of the roll shaft that can pull out the roll sheet by a predetermined conveyance amount when there is no back tension applied to the roll sheet from the roll shaft. . A recording method including a recording process that repeats pitch conveyance for pulling out a predetermined amount of the roll sheet from a roll shaft that rotatably holds a roll sheet wound in a roll shape,
Determining whether the number of windings of the roll sheet has decreased;
After detecting that the number of windings of the roll sheet has decreased, a transport step for pitch transporting the roll sheet by a predetermined transport amount;
Measuring the amount of rotation of the roll shaft rotated in the conveying step;
When the ratio of the rotation amount of the roll shaft to the transport amount of the roll sheet pulled out in the transport step is equal to or less than a first predetermined value, the roll shaft is moved in the direction of feeding the roll sheet. A roll axis rotation step to rotate,
Stopping the recording process when the amount of rotation of the roll shaft rotated in the roll shaft rotation step is less than a second predetermined value;
And a step of continuing the recording process when the amount of rotation of the roll shaft rotated in the roll shaft rotation step is equal to or greater than a second predetermined value. The recording method according to claim 8, wherein
A recording method comprising recording on the drawn roll sheet between the pitch conveyances. The recording method according to claim 8 or 9, wherein
When the roll sheet is pulled out and transported by a predetermined transport amount, a ratio of the rotation amount of the roll shaft to the transport amount of the pulled roll sheet is a third predetermined value that is greater than the first predetermined value. A recording method for detecting that the number of windings of the roll sheet has decreased by detecting that the value has exceeded a value. The recording method according to any one of claims 8 to 10,
A recording method in which the roll shaft is rotated in the direction of feeding out the roll sheet after the pitch conveyance after the step of continuing the recording process. The recording method according to claim 11,
The recording method, wherein an amount of the roll sheet fed out by rotating the roll shaft is equal to or more than a conveyance amount of the roll sheet pulled out in the pitch conveyance. The recording method according to claim 11 or 12,
The pitch conveyance is performed by a conveyance roller that pulls out and conveys the roll sheet,
The rotation amount of the conveyance roller in the pitch conveyance after the step of continuing the recording process is smaller than the rotation amount of the conveyance roller in the pitch conveyance before the step of continuing the recording process by a predetermined correction value. Recording method. The recording method according to claim 13,
The recording method, wherein the predetermined correction value is determined to be a rotation amount of the roll shaft that can pull out the roll sheet by a predetermined conveyance amount when there is no back tension applied to the roll sheet from the roll shaft. .   The program which makes a recording device perform the recording method of any one of Claims 8-14.

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