JP2009181116A - Recording device and medium transportation method in recording device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a recording device capable of detecting an overload on a driving source beforehand prior to transporting a recording medium and transporting the recording medium in a state that there is no overload on the driving source, thereby preventing the deterioration of recording position precision for the recording medium, and a medium transportation method in the recording device. <P>SOLUTION: A feeding device for feeding paper, and transportation means for performing cue, feed and discharge of paper fed have a PF motor as a common driving source. Detection of an overload on the PF motor is carried out in the paper feeding process. If there is no overload detected, the PF motor is driven in a high-speed mode in performing cue, feed, and discharge (Fig.5-(a)). If there is an overload detected, the PF motor is driven in a low-speed mode in performing cue, feed, and discharge (Fig.5-(b)). If an overload is detected twice in a row in the paper feeding process, the paper feeding thereafter is made in a low-speed mode. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a recording apparatus that drives a driving source with an appropriate load when a load of a driving source such as a motor is detected to convey a recording medium, and a medium conveying method in the recording apparatus.

  2. Description of the Related Art Conventionally, a printer as a recording apparatus includes a paper feeding device that feeds paper, a transport unit that performs cueing to a print start position, paper feed for printing, and paper discharge after printing is finished (transport). A roller or the like) uses a motor as a drive source (for example, Patent Document 1). For example, if the sliding frictional resistance of the shaft, the train wheel, etc. on the power transmission path of the conveying means increases due to, for example, deterioration of the conveying means, an excessive load (overload) is applied to the motor. Usually, the motor is set with an operating profile with respect to the rated torque so as to ensure a torque margin that does not cause an overload even under the worst-case conditions assumed.

For example, Patent Document 1 discloses a recording apparatus that avoids securing an unnecessarily large torque margin due to an operation pattern, and sets the torque margin according to the use state to perform efficient control of motor performance. Has been. In this recording apparatus, a storage control device that feedback-controls the drive generates a control information (PWM control voltage value) for controlling the drive of the motor based on the first drive pattern, and a control information And a comparison unit for comparing an overload with respect to driving of the motor, and a second driving pattern for changing the driving load on the motor based on the control information based on the comparison result of the comparison unit. And a setting unit for setting instead of one drive pattern.
JP 2004-90267 A

  However, according to the recording apparatus of Patent Document 1, since the control information is acquired during conveyance (during paper feeding) for recording on paper, the control information is compared with a threshold value for determining overload. Thus, the paper feed before the overload detection result is known (paper feed during overload detection) may be fed in an overload state. In this case, there is a problem that the paper position accuracy of the paper feed when the overload detection is performed is lowered, and the recording position accuracy with respect to the paper is lowered due to this, and it is difficult to obtain a high print image quality.

  Thus, when the paper is fed in an overload state, the paper position accuracy is lowered for the following reason. When paper is fed in an overload state, an excessive current or voltage is applied to the motor in order to reach the target speed, and an excessive torque is generated, which is applied to the motor at the target speed. When the current value or the voltage value is lowered to a value at which the command value is gradually lowered to stop the paper at the desired printing position, the decrement of the command value per time becomes relatively large. This large decrement of the command value causes a large decrement of the motor torque, which causes a variation in speed during deceleration, or a large fluctuation range when the speed increases momentarily when the sliding frictional resistance is locally reduced. Such a cause causes a decrease in accuracy of the stop position of the sheet. Further, in the case of a configuration in which overload detection is performed during paper feeding, for example, when paper feeding is performed on the entire surface of the paper, the feed pitch during paper feeding is minimum, the motor is slow, Since the driving time is extremely short, detection accuracy is difficult to obtain even if overload detection is performed, and erroneous detection is likely to occur.

  The present invention has been made in order to solve the above-described problems, and an object of the present invention is to detect an overload applied to the drive source in advance before transporting the recording medium and to prevent the drive source from being overloaded. An object of the present invention is to provide a recording apparatus and a medium conveying method in the recording apparatus that can suppress a decrease in recording position accuracy with respect to the recording medium by enabling the recording medium to be conveyed.

  The present invention is a recording apparatus for recording on a recording medium, the feeding means feeding the recording medium, the conveying means conveying the recording medium fed by the feeding means, and the conveying means conveying A recording means for recording on the recording medium, a driving source common to the feeding means and the conveying means, a detecting means for detecting an overload applied to the driving source in the feeding process of the recording medium, When the overload is not detected by the detection means, the recording medium is conveyed by the conveyance means in the first speed mode. On the other hand, when the overload is detected, the conveyance of the recording medium is performed. And a control means for controlling the drive source so that the conveyance by the means is performed in a second speed mode which is a speed mode lower than the first speed mode.

  According to the present invention, the overload applied to the drive source is detected by the detecting means during the feeding process of the recording medium. When the detection means does not detect an overload of drive reduction, the control means controls the drive source so that the recording medium is conveyed by the conveyance means in the first speed mode. On the other hand, when an overload is detected, the control unit controls the drive source so that the recording medium is conveyed by the conveying unit in the second speed mode, which is a lower speed mode than the first speed mode. Note that the second speed mode may be composed of a plurality of speed modes so that a slower speed mode is selected as the overload increases in accordance with the magnitude of the overload detected by the detection means.

Hereinafter, a first embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a perspective view showing a basic configuration of the recording apparatus.
As shown in FIG. 1, a printer 11 as a recording apparatus is a serial ink jet printer. The printer 11 is provided with a carriage 14 that is guided by a guide shaft 13 installed in the main body frame 12 and can reciprocate in the main scanning direction X. The carriage 14 is connected to a drive shaft of a carriage motor (hereinafter referred to as a CR motor 16) through an endless timing belt 15 fixed on the back side thereof so that power can be transmitted. As a result, it reciprocates in the main scanning direction X.

  A recording head 17 is provided below the carriage 14. A platen 18 that defines an interval between the nozzle opening surface of the recording head 17 and the paper P as a recording medium is disposed at a lower position facing the recording head 17. Further, the ink supplied from the black color ink cartridges 19 and 20 detachably loaded on the carriage 14 can be ejected (discharged) from the nozzles of the recording head 17 to the paper P. Yes.

  A rear feeding device 22 having a paper feeding tray 21 on which a large number of sheets P can be stacked is provided on the back side of the printer 11, and a front having a paper feeding cassette 24 is provided at the lower front side of the printer 11. A feeding device 25 is provided. The rear feeding device 22 and the front feeding device 25 are automatic paper feeding devices (ASFs) that are used by switching, and a selected side is driven by driving a paper feeding motor (hereinafter referred to as ASF motor 23). The paper P is fed.

  Further, when a paper feed motor (hereinafter referred to as a PF motor 27) is driven, a pair of transport rollers 28 and a pair of discharge rollers 29 (both of which are provided at positions before and after sandwiching the platen 18 on the paper transport path). 2) is rotated, and the paper P is conveyed in the sub-scanning direction Y. Then, a printing operation for ejecting ink from the nozzles of the recording head 17 to the paper P while reciprocating the carriage 14 in the main scanning direction X and a paper feeding operation for feeding the paper P in the sub-scanning direction Y are alternately repeated. Thus, printing is performed on the paper P.

  A linear encoder 30 is provided in the main body frame 12 along the guide shaft 13. The linear encoder 30 outputs a number of pulses proportional to the moving distance of the carriage 14, and the printer 11 detects the output pulse and determines the carriage 14 based on the moving position, moving speed, and moving direction of the carriage 14. The speed control and the position control are performed.

  In FIG. 1, the right end position in the drawing on the movement path of the carriage 14 is a home position (home position) that is disposed when the carriage 14 does not perform printing, and is directly below the carriage 14 disposed at the home position. Is provided with a maintenance device 31 for cleaning the nozzles of the recording head 17. In this example, the so-called on-carriage method in which the ink cartridges 19 and 20 are mounted on the carriage 14 is adopted, but the so-called off-carriage method in which the ink cartridge is provided on the main body frame 12 side is also adopted. Good.

FIG. 3 is a schematic side view illustrating the front feeding device, the transport mechanism, and the recording head.
The front feeding device 25 provided at the bottom of the printer 11 and configured to be able to set paper from the front of the device includes a paper feeding cassette 24, a pickup roller 35, an intermediate roller 36, a retard roller 37, and an assist roller 38. ing. A plurality of sheets P (for example, a predetermined value within a range of 300 to 800 sheets) can be set in a stacked state in the sheet cassette 24 that can be mounted and removed from the front side of the apparatus (however, in FIG. 3). Only one sheet is shown). The pickup roller 35 is provided on a swinging member 40 that swings about a swinging shaft 40a, and the swinging member 40 always swings while being urged toward the paper side by a biasing means (not shown). The printer is in contact with the upper paper.

  As shown in FIG. 3, the intermediate roller 36 is disposed in the vicinity of the downstream side of the sheet feeding cassette 24 in the feeding direction. A retard roller 37 is brought into contact with and separated from the intermediate roller 36, and is rotated following the intermediate roller 36 at the time of contact. Further, the assist roller 38 is in contact with the intermediate roller 36 at a position downstream of the contact position of the retard roller 37. The assist roller 38 is in contact with the intermediate roller 36 and assists the conveyance of the paper P to the downstream side.

  The conveyance roller pair 28 and the conveyance driven roller 41 are capable of nipping the paper P fed by the rotation of the intermediate roller 36 and the assist roller 38 at a position slightly upstream in the feeding direction from the position facing the recording head 17. And a roller 42. Further, the discharge roller pair 29 is arranged so that the sheet P can be nipped at a position downstream of the recording head 17 in the transport direction, and is driven to rotate in contact with the discharge drive roller 43 and the discharge drive roller 43. 44.

  The pickup roller 35 is rotationally driven by driving the ASF motor 23 (see FIG. 1). The intermediate roller 36, the conveyance drive roller 41, and the discharge drive roller 43 are rotationally driven by driving of the PF motor 27 (see FIG. 1). In addition, the retard roller 37 moves between a position in contact with the intermediate roller 36 and a position away from the intermediate roller 36 by driving a sub motor 52 (shown in FIG. 4) described later.

  In addition, a rear end sensor 45 and a front end sensor 46 are provided at a position near the downstream side and a position near the upstream side in the feeding direction across the nip point between the intermediate roller 36 and the retard roller 37, respectively. Further, a paper detection sensor 47 for detecting the leading edge of the paper P being fed is disposed between the assist roller 38 and the transport roller pair 28. The rear end sensor 45, the front end sensor 46, and the paper detection sensor 47 are configured by non-contact sensors such as a transmissive or reflective optical sensor. Of course, at least one of them may be a contact sensor.

  At the time of feeding, the ASF motor 23 and the PF motor 27 are driven while the retard roller 37 is in contact with the intermediate roller 36. The pick-up roller 35 driven by the ASF motor 23 feeds the uppermost paper P one by one from the paper feed cassette 24. The fed paper P is preliminarily separated by the separation slope 24 a and then nipped between the intermediate roller 36 and the retard roller 37, and the leading end of the paper P is nipped by the intermediate roller 36 rotated by the PF motor 27 to the conveying roller pair 28. It is fed to the position to be done. The feeding process is performed until the leading edge of the sheet P is slightly nipped by the conveying roller pair 28. During the feeding process, the leading edge of the paper P is detected by the paper detection sensor 47, and the PF counter 87 (see FIG. 4) that counts the rotation amount of the PF motor 27 with this detection position as a reference (origin). The transfer position is grasped. When the paper feeding process is completed, the driving of the ASF motor 23 is stopped.

  After the paper feeding process is completed, the PF motor 27 is driven in reverse to drive the transport roller pair 28 in reverse. At this time, since the intermediate roller 36 is configured so as not to be able to reversely rotate, the sheet P bends gradually with the reverse rotation of the conveying roller pair 28, and when the nip at the leading end is opened, the sheet is rebounded by the bending. When the leading end of P abuts against the roller surface of the conveying roller pair 28, the paper P is skewed.

After the skew removal, a cueing operation, a printing operation, and a paper discharge operation are sequentially performed. The conveyance of the paper P in each of these operations is performed by driving the PF motor 27.
The cueing operation is performed when the PF motor 27 is driven to rotate forward again after the skew is removed, and the paper P is conveyed to the cueing position (print start position). After the cueing is completed, the printing operation is started. In the printing operation, a printing operation for printing one raster line (one line) on the paper P by ejecting ink droplets from the recording head 17 in the process of moving the carriage 14 once in the main scanning direction X by the CR motor 16; Then, the paper feeding operation for transporting the printed paper P by a predetermined feed pitch to the next line printing start position is alternately performed, whereby the printing on the paper P is advanced. The paper P after printing is discharged to a stacker (not shown) provided on the front side of the apparatus while being nipped by the discharge roller pair 29.

  By the way, the paper feed cassette 24 of the present embodiment is relatively deep in order to earn a large number of sheets. For this reason, if it is configured to start feeding the succeeding sheet P2 (next page) after the printing of the preceding sheet P1 (previous page), it is necessary from the end of printing of the preceding sheet P1 to the start of printing of the succeeding sheet P2. Time will be quite long. In order to avoid such a problem, in the present embodiment, the feeding operation of the trailing edge of the preceding paper P1 and the succeeding paper P2 is advanced in parallel during the printing operation of the preceding paper P1, and the preceding paper at the start of feeding of the succeeding paper is advanced. Inter-page control processing is employed in which the interval between the paper P1 and the succeeding paper P2 is reduced.

  This inter-page control process is performed as follows. When the trailing edge of the preceding paper P1 is detected by the trailing edge sensor 45, the ASF motor 23 is driven to start feeding the subsequent paper P2 (preliminary paper feeding). When the leading edge of the succeeding paper P2 is detected by the leading edge sensor 46, when it is grasped from the count value of the ASF counter 88 (see FIG. 4) that a predetermined amount of feeding has been performed from the detection position, The driving of the ASF motor 23 is stopped. As a result, the succeeding paper P2 is arranged in a state where the leading edge reaches the position near the upstream side in the feeding direction with respect to the nip point between the intermediate roller 36 and the retard roller 37. Thereafter, the distance (inter-paper distance) between the trailing edge position of the preceding paper P1 and the leading edge position (fixed value) of the succeeding paper P2 ascertained from the count value of the PF counter 87 (see FIG. 4) is calculated. After satisfying the condition that the calculated distance is ensured by a predetermined amount or more, the ASF motor 23 is also driven at the next paper feeding, and the paper feeding of the preceding paper P1 and the feeding of the succeeding paper P2 are performed in parallel. The same transport amount is advanced. As a result, the feeding of the succeeding paper P2 is advanced in a state in which the necessary inter-paper distance is ensured during the printing operation of the preceding paper P1.

  In this embodiment, the conveyance speed control for detecting the load applied to the PF motor 27 and selecting the conveyance speed of the paper P in the paper feeding process, the cueing process, the paper feeding process, and the paper discharging process according to the load. Is adopted. This transport speed control will be described later.

Next, the electrical configuration of the printer will be described with reference to FIG.
As shown in FIG. 4, the printer 11 includes a controller 50 that performs various controls. The controller 50 is communicably connected to a host device (not shown) via the interface 51, and controls the printing operation and the like of the printer 11 based on print data received from the host device.

  A CR motor 16, an ASF motor 23, a PF motor 27, and a sub motor 52 are connected to the controller 50 as an output system. The controller 50 is connected with a power switch 53, a linear encoder 30, encoders 54 and 55 (rotary encoder), a rear end sensor 45, a front end sensor 46, and a paper detection sensor 47 as an input system.

  The controller 50 includes a control unit 60, a head driver 61, and motor drivers 62, 63, 64, 65. The controller 60 drives the recording head 17 via the head driver 61 based on the print data, and draws an image or document based on the print data by forming dots by ejecting ink droplets. In addition, the control unit 60 controls driving of the CR motor 16 via the motor driver 62 and controls movement of the carriage 14 in the main scanning direction. At this time, the control unit 60 grasps the movement position of the carriage 14 relative to the origin position (home position) by counting the input pulses from the linear encoder 30 with a counter (not shown). The input pulse from the linear encoder 30 is also used for generating an ejection timing signal for the recording head 17.

The control unit 60 drives the ASF motor 23 via the motor driver 64. The driving force of the ASF motor 23 is transmitted to the pickup roller 35 of the front feeding device 25.
The control unit 60 drives the sub motor 52 via the motor driver 65. Here, on each power transmission path of the PF motor 27 and the sub motor 52, clutch portions 57 and 58 for selecting one of the rear feeding device 22 and the front feeding device 25 as a power transmission destination are interposed. When the sub motor 52 is driven forward / reversely, the hopper 67 and the retard roller 68 are moved between the retracted position and the paper feeding position when the rear feeding device 22 side of the clutch portion 57 is selected, while the clutch portion When 57 is selected on the front feeding device 25 side, the retard roller 37 and the paper return lever 69 are moved between the retracted position and the paper feeding position. The paper return lever 69 closes the feeding port for reaching the nip position between the intermediate roller 36 and the retard roller 37 at the retracted position arranged during the printing process to prevent the subsequent paper P2 from entering, and is arranged at the time of paper feeding. At the paper feeding position, the feeding port is opened to allow the subsequent paper P2 to enter. The selection of the rear feeding device 22 and the front feeding device 25 is performed when the user activates a printer driver of the host device and operates an input device (both not shown). In this case, one of the feeding device options may be selected and specified on the display screen, or when the paper type or paper size is specified, the printer driver may select the feeding device based on the specified information. .

  Further, the control unit 60 drives the PF motor 27 via the motor driver 63. When the PF motor 27 is driven, the feed roller 66 is rotationally driven via a train wheel (not shown) when the clutch unit 58 is selected on the front feeding device 25 side, while the rear feeding device 25 side of the clutch unit 58 is driven. At the time of selection, the intermediate roller 36 is rotationally driven via a train wheel (not shown). Further, the conveyance drive roller 41 and the discharge drive roller 43 are always driven to rotate regardless of the selection of the feeding device of the clutch portion 58. However, when the PF motor 27 is driven in reverse rotation, the conveyance drive roller 41 and the discharge drive roller 43 are driven in reverse rotation by the action of the clutch unit 58, but the intermediate roller 36 and the paper feed roller 66 cannot be rotated in reverse. Yes.

  As described above, in this embodiment, the PF motor 27 includes the rear feeding device 22 (particularly, the paper feeding roller 66) and the front feeding device 25 (particularly, the intermediate roller 36) serving as feeding means, and the conveying means. This is a common drive source for the conveyance roller pair 28 and the discharge roller pair 29. That is, the PF motor 27 is a common drive source in all the conveyance system processes of paper feeding, cueing, paper feeding, and paper ejection.

  The control unit 60 includes a main control unit 71, a head control unit 72, a carriage control unit 73, a PF control unit 74, an ASF control unit 75, an SM control unit 76, a nonvolatile memory 77, and a memory 78. The main control unit 71 corresponds to an upper layer that performs overall control of the control units 72 to 76, and each control unit 72 to 76 corresponding to the lower layer (sequence control layer) according to an instruction from the main control unit 71 is the recording head 17. The CR motor 16, the PF motor 27, the ASF motor 23, and the sub motor 52 are driven and controlled. The control unit 60 includes, for example, a CPU, an ASIC (Application Specific IC (IC)), a RAM, a nonvolatile memory 77, a memory 78 (eg, ROM), and the like, and the CPU is a nonvolatile memory. 77 or by executing a program stored in the memory 78. Of course, the control unit 60 is not limited to a software configuration, and may be configured by hardware such as an electronic circuit (for example, a custom IC), or may be configured by cooperation of software and hardware.

  Here, the above-described conveyance speed control is performed by the main control unit 71 and the PF control unit 74 drivingly controlling the PF motor 27. The reason for adopting this conveyance speed control is as follows. The sliding resistance acting on the various rollers, the train wheel, etc. of the transport system fluctuates so as to increase due to deterioration over time, and when this sliding resistance increases, the load on the PF motor 27 increases. When the load applied to the PF motor 27 increases, the rotational speed does not reach the target speed or is delayed until the PF control unit 74 supplies a current corresponding to the target speed to the PF motor 27 via the motor driver 63. Occurs. Therefore, the PF control unit 74 increases the command value so that the PF motor 27 reaches the target speed (constant speed) and increases the current to be supplied to the PF motor 27. However, due to the excessive supply current at this time, the rotational torque of the PF motor 27 becomes larger than when the load is normal, and the supply current at the start of deceleration is large. The stop position accuracy is reduced because of the increase of. This means that the position accuracy of the cueing position and the paper feeding position of the paper P is lowered.

  Therefore, in the present embodiment, the conveyance speed control is adopted to determine the speed mode according to the load of the PF motor 27. In this conveyance speed control, a load applied to the PF motor 27 is detected in the paper feeding process, and if the load is not detected (determined) as an overload, the PF motor 27 is set in a normal high speed mode (first speed mode). On the other hand, if it is detected (determined) that the load is overloaded, the PF motor 27 is driven in a low speed mode (second speed mode) which is a speed mode slower than normal.

  Hereinafter, the specific content of the conveyance speed control which the control part 60 of FIG. 4 performs is demonstrated. As shown in FIG. 4, the main control unit 71 includes a timer 81, an overload detection counter 82, and a mode setting unit 83 that are used for controlling the transport system. The PF control unit 74 includes an overload detection unit 84 and a PF counter 87 having an interrupt number counter 85 and a determination unit 86. The ASF control unit 75 includes an ASF counter 88. The nonvolatile memory 77 also includes a flag F indicating the selected speed mode by “0” or “1”, and a speed table PT for PF motor (hereinafter also simply referred to as “PF speed table PT”). It is remembered. Further, the memory 78 stores an ASF motor speed table AT (hereinafter also referred to as “ASF speed table AT”). Two types of PF speed table PT and ASF speed table AT are prepared for the high speed mode and the low speed mode, respectively. The flag F indicates “high speed mode” when it is “0”, “low speed mode” when it is “1”, and is stored in the non-volatile memory 77 so that it is saved even while the power is shut off, and the next power It is possible to read and grasp at the time of loading.

  When starting the transfer control, the main control unit 71 instructs the PF control unit 74 to transfer and activates the timer 81. Whenever the timer 81 counts a certain interrupt time from the start of transfer, the main control unit 71 An interrupt signal IS is output.

  The PF control unit 74 reads the PF speed table PT corresponding to the speed mode set by the mode setting unit 83 from the nonvolatile memory 77. The interrupt number counter 85 counts the number of interrupts every time an interrupt signal IS is input from the main control unit 71 to the PF control unit 74. Then, the PF control unit 74 refers to the PF speed table PT, and the PF motor 27 via the motor driver 63 so that the target speed corresponding to the number of interruptions counted by the interruption number counter 85 at that time is obtained. The speed control.

  FIG. 2 is a graph showing a speed profile when the speed is controlled using the PF speed table. FIG. 2 shows an example of a speed profile when the PF control unit 74 performs the paper feed speed control. The PF control unit 74, based on the information on the transport distance (in this example, the paper feed distance) received together with the transport instruction from the main control unit 71, from the nonvolatile memory 77, a plurality of speed modes corresponding to the speed mode to be adopted at that time. The speed table PT of the target speed Vo corresponding to the transport distance at that time is read from the speed table PT. Since the paper feed distance is relatively longer than the paper feed distance, the PF speed table PT having the same target speed Vo is basically read.

  In the speed profile shown in FIG. 2, the PF speed table PT includes an acceleration table PTα indicating a command value of the paper feed speed Vpf in the acceleration process and a deceleration table PTβ indicating a command value of the paper feed speed Vpf in the deceleration process. The acceleration table PTα is set such that the initial speed starts from a value near “0”, passes through a predetermined acceleration profile, and the final target speed becomes the target speed Vo (constant speed), and reaches the target speed Vo from the acceleration start time. Table data showing the correspondence between the number of interrupts until and the target speed Vg. The deceleration table PTβ is set such that the initial speed starts from the target speed Vo, the final target speed becomes the stop speed “0” through a predetermined deceleration profile, the number of interruptions from the start of deceleration to the stop, and the target It is table data which shows a correspondence with speed Vg. Each time the interrupt signal IS is input from the main controller 71 (the timing of the arrow in FIG. 2), the PF controller 74 instructs the motor driver 63 to provide a command value corresponding to the target speed Vg corresponding to the number of interrupts at that time. In response to the command, a current corresponding to the command value is supplied from the motor driver 63 to the PF motor 27. Such a PF speed table PT is prepared for each speed mode. Similarly, the ASF motor speed table AT includes an acceleration table and a deceleration table indicating the correspondence between the number of interruptions and the target speed Vg. In the present embodiment, the same speed table PT for the PF motor is used for paper feeding and conveyance (cueing, paper feeding, paper discharging). A table may be provided separately for each speed mode.

  In this example, when the PF control unit 74 commands a command value corresponding to the target speed Vg corresponding to the number of interruptions, the motor driver 63 supplies a current value corresponding to the target speed Vg to the PF motor 27. The PF control unit 74 counts the number of pulses input per unit time from the encoder 54 and acquires the actual rotational speed of the PF motor 27 from the counted value. For example, during acceleration, the actual rotational speed reaches the target speed Vo until the actual rotational speed reaches the target speed Vo. Interruption processing for instructing the motor driver 63 with a command value corresponding to the target speed Vg corresponding to the number of interrupts from time to time is repeated. For this reason, while the load of the PF motor 27 is small, the target speed Vo is reached with the number of interruptions within the specified number of times. However, when the load increases, the number of interruptions until the target speed Vo is reached exceeds the specified number of times.

  Returning to FIG. 4, the determination unit 86 determines that the interrupt count K counted until the interrupt count counter 85 reaches the target speed Vo from the acceleration start point in the paper feeding process exceeds the overload determination threshold Ks (K > Ks). In the graph of FIG. 2, the solid line acceleration profile indicates a normal load when the PF motor 27 is not overloaded, and the two-dot chain line acceleration profile indicates an overload when the PF motor 27 is overloaded. The thing is shown. When the load of the PF motor 27 is normal, the target speed Vo is reached in a normal required time, as indicated by a solid line in FIG. 6, and therefore the target speed Vo is reached at the number of interruptions K (K ≦ Ks) equal to or less than the threshold value Ks. On the other hand, when the PF motor 27 is overloaded, the time required to reach the target speed Vo becomes longer than normal, and the number of interruptions K until the target speed Vo is reached, as indicated by a two-dot chain line in FIG. Exceeds the threshold value Ks (K> Ks). Therefore, if the interrupt count K does not exceed the threshold value Ks (K ≦ Ks), the determination unit 86 determines that the PF motor 27 is not overloaded. On the other hand, if the interrupt count K exceeds the threshold value Ks (K > Ks), it is determined that the PF motor 27 is overloaded. As described above, the overload detection unit 84 detects the overload of the PF motor 27 using the interrupt number counter 85 and the determination unit 86.

  The PF controller 74 notifies the main controller 71 of the detection result of the overload detector 84 after the paper feed speed reaches the target speed Vo. In the main control unit 71, the overload detection counter 82 counts “1” when the detection result of the overload detection unit 84 is “overload”. The PF control unit 74 performs overload detection in the paper feeding process twice, and when the count value of the overload detection counter 82 becomes “2”, that is, the flag F is not detected until two overloads are continuously detected. = 1 (low speed mode).

  This is because if the overload is detected only once, there is a possibility that the overload is erroneously detected due to the double feeding of the paper P. Once the low-speed mode is set due to this type of erroneous detection, there is a disadvantage that paper feeding, cueing, paper feeding and paper discharge are performed in the low-speed mode thereafter. The reason why it is twice is that the double feed of the paper P is likely to occur twice consecutively, and the PF motor is detected when an overload is detected continuously in two paper feeds. 27 determines that there is an overload. For this reason, even if an overload is detected in the first paper feed, the paper feed is performed in the high speed mode until the second overload detection is performed. However, cueing, paper feeding and paper discharge after paper feeding are performed immediately in the low speed mode if an overload is detected during the first paper feeding.

  This is to avoid conveyance of the PF motor 27 in a high torque state (overcurrent supply state), which is a cause of lowering the positional accuracy of the cue position and the paper feed position. Of course, the paper discharge that does not affect the printing position accuracy may be performed in the high speed mode. In this embodiment, a PF overload detection execution counter (not shown) for counting the number of overload detections of the PF motor 27 is provided, and the count value is less than “2” after the power is turned on. Load detection and overload detection are executed only during the first two paper feeds.

  Based on the detection result of the overload detection unit 84, the mode setting unit 83 sets the speed mode of the PF motor 27 and the ASF motor 23 at the time of paper feeding and at the time of conveyance (at the time of cueing, paper feeding, and paper ejection). . Specifically, the mode setting unit 83 sets the “high speed mode” for the paper feed speed mode when the count value is less than “2” based on the count value of the overload detection counter 82. When the count value is “2”, the “low speed mode” is set. Further, the mode setting unit 83 sets the “high speed mode” and “overload” when the detection result of the overload detection unit 84 is “no overload” for the speed mode at the time of cueing, paper feeding and paper discharge. In the case of, set “Low-speed mode”. When the front feeding device 25 is selected, the mode setting unit 83 sets the speed mode of the PF motor 27 at the time of paper feeding (hereinafter also referred to as “ASF speed mode”) as the speed mode for the ASF motor (hereinafter also referred to as “ASF speed mode”). Hereinafter, the same speed mode as “PF speed mode” is set. For this reason, the ASF control unit 75 refers to the ASF speed table AT corresponding to the ASF speed mode set by the mode setting unit 83 and repeats the interrupt process every time the interrupt signal IS is input from the main control unit 71. This is executed to control the speed of the ASF motor 23.

  The PF counter 87 is reset when the paper detection sensor 47 detects the leading edge of the paper P, and counts the number of pulses proportional to the rotation amount of the PF motor 27 based on the input pulse from the encoder 54 after the reset. From the count value of the PF counter 87, the PF control unit 74 grasps the transport position of the paper P with the paper position when the leading edge of the paper P is detected by the paper detection sensor 47 as a reference (origin). The ASF counter 88 is reset when the leading edge of the succeeding paper P2 is detected by the leading edge sensor 46. After this reset, the ASF counter 88 counts the number of pulses proportional to the rotation amount of the ASF motor 23 based on the input pulse from the encoder 55. . The ASF control unit 75 grasps the feeding position of the succeeding sheet P2 based on the count value of the ASF counter 88 with the succeeding sheet position as the reference (origin) when the leading edge sensor 46 detects the leading edge of the succeeding sheet P2. When the trailing edge of the preceding paper P1 is detected by the trailing edge sensor 45 during printing, the ASF control unit 75 continues to the standby paper until the leading edge of the succeeding paper P2 reaches a predetermined position slightly before the nip point of the intermediate roller 36. P2 is preliminarily fed.

  Next, the conveyance speed control process performed by the control unit 60 will be described with reference to the flowcharts shown in FIGS. When the power switch 53 of the printer 11 is turned on by the user, the printer 11 is initialized, and a printer initialization routine shown in FIG. 6 is executed as one process during the initialization process. At this time, it is assumed that the flag F is “0”. In this case, as shown in FIG. 6, it is determined in step S10 that the flag F = 0, the process proceeds to step S50, the overload detection counter 82 is reset, and the number of overload detections is set to “0”. The initialization process when flag F = 1 will be described later.

  Hereinafter, the conveyance speed control process of the PF motor 27 will be described with reference to FIGS. As an example, the printer 11 performs a printing operation for one print job for printing a plurality of sheets. Further, a case where the front feeding device 25 is selected and paper feeding is performed from the front feeding device 25 is taken as an example. For example, when the printer 11 receives print data from the host device, the printer 11 starts print processing.

  First, the main control unit 71 reads the flag F from the nonvolatile memory 77 and determines whether or not the flag F is “1” (low speed mode). Since the flag F = 0, the high speed mode is adopted as the PF speed mode (S120).

  Then, the paper feed process is executed according to the adopted PF speed mode (S140). That is, the main control unit 71 causes the ASF control unit 75 to drive the ASF motor 23 in the high speed mode and causes the PF control unit 74 to drive the PF motor 27 in the high speed mode. That is, the PF control unit 74 stores the speed table PT in which the target speed Vo corresponding to the instructed feeding distance is set from the speed table PT for the low speed mode stored in the nonvolatile memory 77. From the memory 77. Then, the first target speed Vg is acquired with reference to the read speed table PT, and a current corresponding to the first target speed Vg is supplied to the PF motor 27. Thereafter, the interrupt signal IS is sequentially input at a constant interrupt time interval, and the interrupt counter 85 is incremented by “1” for each input, and the speed table PT is referred to determine the interrupt count at that time. A corresponding target speed Vg is acquired, and a current corresponding to the target speed Vg is supplied to the PF motor 27. Thus, acceleration control is performed until the PF motor 27 reaches the target speed Vo.

  At this time, since the PF overload detection execution counter is “0”, the PF load detection process is performed in this paper feed process. That is, after the PF motor 27 reaches the target speed Vo, the interrupt count K counted until the interrupt counter 85 reaches the target speed Vo in the acceleration process is used for subsequent overload detection (overload determination). In order to do so, it is temporarily stored in a predetermined buffer. Thereafter, the PF motor 27 is maintained at the target speed Vo (constant speed), and the paper P is fed at the target paper feed speed. Then, the leading edge of the paper P is detected by the paper detection sensor 47 during feeding, and the PF counter 87 counts the transport position of the paper P with the leading edge detection position as the origin. When the transport position of the paper P reaches the deceleration start position, the deceleration of the PF motor 27 is started. When the driving of the PF motor 27 is stopped, the paper P stops at the target paper feed position where the paper P is slightly nipped between the transport roller pair 28.

  In the next step S150, it is determined whether or not the high speed mode is adopted. Since the high-speed mode is adopted, the process proceeds to step S160 to determine whether or not a PF overload is detected. That is, the number of interruptions K is read from the buffer, and it is determined whether or not the number of interruptions K until reaching the target speed Vo exceeds the threshold value Ks (K> Ks).

  If the PF overload is not detected (K ≦ Ks), the overload detection count, which is the count value of the overload detection counter 82, is reset to “0” (step S170). On the other hand, if a PF overload is detected (K <Ks), the process proceeds to step S180, and the number of detected PF loads during feeding, which is a count value of the overload detection counter 82, is incremented. As a result, the number of times of PF overload detection during feeding is “1” this time, which is the first feeding.

  Then, in the next step S190, it is determined whether or not the overload detection count is less than “2”. Since the number of times of overload detection is “1” this time, the process proceeds to step S210 and the low speed mode is adopted as the PF speed mode. If no PF overload is detected (No in S160), the setting of the PF speed mode to be adopted (S120, S130) is not changed.

In the next step S220 (FIG. 8), the cueing process is executed in the adopted PF speed mode.
Then, after the cueing, the paper feed process (step S230) performed in the adopted PF speed mode, and the ink droplets are ejected from the recording head 17 while moving the carriage 14 in the main scanning direction, and one raster line (one line). ) Is repeatedly performed until it is determined that printing of one page has been completed (step S250).

When the printing of one page is completed, the paper discharge process is executed in the adopted PF speed mode (step S260).
In step S270, it is determined whether all pages have been printed. If printing of all pages has not been completed, the process returns to step S110.

When printing of the first page is completed in this way, printing of the second page is started next.
When printing the second page is started, first, in step S110, it is determined whether or not the flag F is “1” (low speed mode). Here, the flag F is set to “1” when the number of times of overload detection becomes two. Therefore, on the first page, when the PF motor 27 is overloaded, when double feeding occurs, or when neither the overloading of the PF motor 27 nor double feeding occurs However, the flag F does not become “1”. Therefore, since the flag F is not “1” in step S110 on the second page (negative determination), the high speed mode is adopted as the PF speed mode (S120).

  Then, the paper feed process is executed in the adopted PF speed mode, that is, the high speed mode (S140). At this time, since the PF overload detection execution counter is “1”, the PF load detection process is performed in this paper feed process. That is, after the PF motor 27 reaches the target speed Vo, the interrupt count K until the target speed Vo is reached is acquired from the interrupt counter 85 and temporarily stored in a predetermined buffer.

  Since the high-speed mode is adopted for the paper feed process (Yes in S150), it is determined whether or not a PF overload is detected in Step S160. That is, the number of interruptions K until the target speed Vo is reached is read from the buffer, and it is determined whether or not K> Ks is satisfied.

  For example, when a PF overload is detected because the PF motor 27 is actually overloaded during the paper feeding process for the first page, the reason for the overload applied to the PF motor 27 this time on the second page as well. In addition, K> Ks is established and the PF overload is detected. On the other hand, if K> Ks is established and PF overload is detected because double feed has occurred in the process of feeding the first page, it is very likely that double feed will occur continuously for two pages. Since it is rare, the PF overload is not detected this time on the second page. In this case, the process proceeds to step S170, the overload detection counter 82 is reset, and the overload detection count is set to “0”. Further, when the PF motor 27 is not overloaded, the PF overload is not detected on the first page or the second page. Therefore, also in this case, the overload detection counter 82 is reset to set the number of overload detections to “0”. However, in some cases, double feed occurs on the second page and a PF overload is detected.

  For example, when the PF motor 27 is overloaded, the PF overload is detected again this time on the second page (affirmative determination in S160), and the number of PF overload detections during feeding is also incremented on the second page. (S180). As a result, the number of detected PF overloads during feeding becomes “2”.

Since the overload detection count <2 is not established in the determination process in step S190 (negative determination), the flag F is set to 1 (low speed mode) (S200).
Since the low speed mode is adopted as the PF speed mode in the next step S210 after the second page paper feed process, the cueing process, the paper feed process, and the paper discharge process are executed in the adopted low speed mode (S220, S230). , S260). If there is still a next page to be printed after the second page is printed (No in S270), the process returns to step S110 to print the third page.

  In step S110 on the third page, since the flag F = 1, the low speed mode is adopted as the PF speed mode (S130). For this reason, even if an overload is applied to the PF motor 27, the paper feed process is performed in the low speed mode only for the third page (S140). In the paper feed process for the third page, since the PF overload detection execution counter is “2”, the PF load detection process is not performed. This is because if a PF overload is detected twice (page 2) continuously, there is a very high possibility that the PF motor 27 is actually overloaded. Load detection processing and overload detection are not performed. Thus, for the third and subsequent pages, all of the paper feed process (S140), cueing process (S220), paper feed process (S230), and paper discharge process (S260) are performed in the low speed mode. Then, when printing of all pages is completed, the conveyance speed control routine is ended.

  A case where there is no overload and a case where there is an overload will be described with reference to FIG. FIG. 5 is a graph for explaining the contents of the conveyance speed control in the case of (a) no overload and (b) the case of overload. This is an example of printing a plurality of sheets in one print job. In each graph, the horizontal axis indicates the print page, and the vertical axis indicates the conveyance speed of the PF motor 27. The conveyance speed in the high speed mode is indicated by Vh, and the conveyance speed in the low speed mode is indicated by Vl. Note that the actual speed varies depending on the distance to which the paper P is fed, such as the paper feed distance, the cue distance, the paper feed distance, and the paper discharge distance. However, in FIG. 5, the speed mode employed can be seen. The PF motor 27 is distinguished only by the speed Vh in the high speed mode and the speed Vl in the low speed mode. In the initial state, it is assumed that the overload detection count is “0” and the flag F = 0.

  In the case of no overload shown in FIG. 5A, paper feeding is performed on the first page in the high speed mode. At this time, load detection processing is performed, but no overload is detected. ”, The flag F remains zero. Then, cueing, paper feeding and paper discharge are performed in a high speed mode. Next, since the flag F = 0 on the second page, paper feed processing is performed in the high speed mode, and load detection processing is performed during this paper feed processing, but no overload is detected. Therefore, cueing, paper feeding and paper discharge are performed in the high speed mode. For the third and subsequent pages after two consecutive overloads are not detected, load detection processing and overload detection are not performed during paper feed, and all of paper feed, cue, paper feed, and paper discharge are in high-speed mode. Done in For this reason, all pages are fed and transported in the high-speed mode, so that high throughput can be obtained.

  On the other hand, in the case of an overload shown in FIG. 5B, paper feed is performed on the first page in the high speed mode, and at this time, a load detection process is performed to detect the overload. For this reason, the number of overload detections is “1” and the flag F = 0. Then, cueing, paper feeding and paper discharge for the first page in which overload is detected during paper feeding are performed in the low speed mode. Next, since the flag F = 0 on the second page, the sheet is fed in the high speed mode, and an overload is detected by the load detection process during the sheet feeding process. As a result, the overload detection count becomes “2”, and the flag F is changed from “0” to “1”. For this reason, cueing, paper feeding and paper discharge are performed in the low speed mode. When the third and subsequent pages are fed, load detection processing and overload detection are not performed, and paper feeding, cueing, paper feeding, and paper ejection are all performed in the low speed mode. For this reason, the PF motor 27 does not enter an excessive torque state (excessive current supply state), the accuracy of the stop position of the paper P during cueing and paper feeding is improved, and even if the PF motor 27 is in an overload state, the high Image quality printing is possible. In the above description, one print job for continuous printing of a plurality of sheets is taken as an example. However, for example, overload is detected on the last page of the first print job in two print jobs, and the first page of the next print job is detected. Even if an overload is detected, the number of times of overload detection is two, and all subsequent paper feeding and conveyance in printing is performed in the low speed mode. Since the value of the flag F is stored in the nonvolatile memory 77, it is saved even after the printer 11 is turned off.

  Next, the printer initialization routine will be described with reference to the flowchart of FIG. When the user turns on the power switch 53 to turn on the printer 11, the control unit 60 executes an initialization process for the printer 11. As one process of this initialization process, the printer initialization process shown in FIG. 6 is executed.

  First, in step S10, it is determined whether or not the flag F is “1” (low speed mode). If the flag is not F = 1, that is, if F = 0 and the speed mode employed before the power is turned off last time is the high speed mode, the overload detection count is set to “0” (step S50). On the other hand, if the flag F = 1, the PF motor 27 is driven (PF drive) in the high-speed mode, and load detection processing (acquisition of interrupt count K) is performed during the PF drive (step S20). At this time, the PF control unit 74 refers to the PF speed table for the high speed mode under the same conditions as those during paper feeding.

  In the next step S30, it is determined whether an overload is detected (K> Ks). If no overload is detected, the flag F is set to “0” (high speed mode) (step S40). On the other hand, if an overload is detected, the overload detection counter 82 is reset to set the number of overload detections to “0” (step S50).

  For example, if the flag F before the previous power shutdown is “1” (low speed mode) and an overload is detected in the initialization process when the power is turned on this time, the flag F remains at 1. In this case, in the transport speed control routine shown in FIGS. 7 and 8 executed at the time of subsequent printing, it is determined that the flag F = 1 (Yes in S110), so the low speed mode is set as the PF speed mode ( S130). For this reason, paper feeding, cueing, paper feeding, and paper discharge are all performed in the low speed mode from the first page (S140, S220, S230, S260).

  On the other hand, even if the flag F before the previous power cut-off is “1” (low speed mode), the flag F is changed to “0” if no overload is detected in the initialization process when the power is turned on this time. At the same time (S40), the overload detection counter 82 is reset and the number of overload detections becomes “0” (S50). In this case, in the transport speed control routine shown in FIGS. 7 and 8 executed at the time of subsequent printing, it is determined that the flag F = 0 (No determination in S110), so the high speed mode is set as the PF speed mode ( S120). For this reason, the paper feed process is performed in the high-speed mode, and the load detection process is performed in the middle (S140). If an overload is detected, the first page is cued, fed, and discharged in the low speed mode. Furthermore, if the paper feed process is performed in the high speed mode on the second page and an overload is detected as a result of the load detection process performed in the middle, the overload detection count is “2” and the flag F is “1”. Is changed. Therefore, after the cueing, paper feeding, and paper discharge of the second page are performed in the low speed mode, all of the paper feeding, cueing, paper feeding, and paper ejection are performed in the low speed mode after the third page. For this reason, even when the overload is not detected in the initialization process and the flag F is changed from “1” to “0”, the load is detected again at the time of paper feeding and the overload is continuously detected twice. If so, the low speed mode is restored. Therefore, it is possible to avoid the inconvenience that the high-speed mode is adopted in the subsequent printing when an overload is not detected in the initialization process. Since the driving of the PF motor 27 performed in the initialization process is performed without the paper P, the load on the PF motor 27 is less than that of the actual paper feeding, so the load is excessive. As the threshold value Ks used for detection, it is desirable to employ a slightly smaller value that allows for the load of the paper P. Also, when the rear feeding device 22 is selected and printing is performed, basically the same transport speed control is performed only by not driving the ASF motor 23. However, since the load applied to the PF motor 27 at the time of driving the PF motor 27 is strictly different between the rear feeding device 22 and the front feeding device 25, it is desirable to adopt a value that matches each of the threshold values Ks. Further, the overload detection (speed mode determination process) may be performed by both the rear feeding device 22 and the front feeding device 25, or may be performed only on the first paper feeding side after the power is turned on. Good. If both are performed and the overload detection result (determination speed mode) is different between the two, one of the predetermined detection results may be adopted.

As described above in detail, according to this embodiment, the following effects can be obtained.
(1) When the load of the PF motor 27 is detected at the time of paper feeding and the load is detected as being overloaded, the feeding and feeding of the fed paper P are performed in the low speed mode. That is, when overload is detected by detecting (determining) in advance whether or not an overload is applied to the PF motor 27 during the cueing / paper feeding process of the paper P. Usually, the cueing / paper feeding that should be performed in the high speed mode is switched to the low speed mode. Accordingly, since the PF motor 27 is driven with an excessive torque due to an overload at the time of cueing and paper feeding for determining the recording position on the paper P, the stop position accuracy of the paper P (cueing position / paper feeding position) ) Can be avoided. Therefore, even if the sliding frictional resistance applied to the shaft of the transport roller or the train wheel of the transport system becomes large due to deterioration over time and the PF motor 27 is overloaded, the torque of the PF motor 27 is suppressed to an appropriate range. It is possible to maintain high positional accuracy of the position and the paper feed position. In addition, since the PF motor 27 is driven in the low speed mode, the power consumption of the PF motor 27 can be reduced. Therefore, even when an overload is applied to the PF motor 27, high-quality printing can be performed while suppressing power consumption of printing.

  (2) Overload detection is performed over two times of paper feeding, and when the overload is detected twice in succession, the low speed mode is determined, and the subsequent paper feeding / conveying is performed in the low speed mode. I made it. Therefore, for example, since the overload is erroneously detected due to the double feeding of the paper P, it is possible to avoid the inconvenience that the low speed mode is erroneously determined.

  (3) A configuration is adopted in which the paper feed speed is set to the low speed mode only after the overload of the PF motor 27 during paper feed is detected twice consecutively. Therefore, compared to the configuration in which the paper feeding is performed in the low speed mode by detecting one overload that may cause double feeding of the paper P, a higher throughput can be obtained as much as the paper feeding is performed at a high speed. That is, it is possible to avoid a decrease in throughput due to a low paper feeding speed due to erroneous detection due to double feeding of the paper P.

  (4) Based on the value of the flag F during the initialization process when the printer 11 is turned on, it is determined whether the previous speed mode that the printer 11 has used before power-off is the high speed mode or the low speed mode, and the low speed mode is adopted. In the initialization process, the load detection and the overload detection are performed by driving the PF motor 27 under the same conditions as the sheet feeding. Therefore, it is not necessary to perform load detection and overload detection when feeding paper during printing. When the flag F = 0 in the initialization process, the overload of the PF motor 27 is detected in the paper feeding process during the subsequent printing, although the overload is not detected during the initialization process. Therefore, even when the PF motor 27 is overloaded for some reason since the power is turned on this time, it is possible to detect the overload and perform paper feeding, cueing, and paper feeding in the low speed mode.

Note that the present invention is not limited to the above embodiment, and the following forms can also be adopted.
(Modification 1) Although load detection is performed by the number of interruptions K until the target speed Vo is reached, it may be performed by a motor command value (for example, duty value) when the target speed Vo is reached. In this case, it is assumed that an overload is detected if the motor command value exceeds the threshold value. When a motor command value or the like is used, load detection may be performed in a constant speed range, not limited to the acceleration process of the paper feeding process.

(Modification 2) In the above-described embodiment, when an overload is detected, the paper feed speed mode is also set to the low speed mode.
(Modification 3) In the above-described embodiment, a configuration is adopted in which overload detection is performed at the time of first printing after power-on to determine the speed mode to be adopted at the time of conveyance, and the speed mode determination processing is first performed once every power-on. Although it was set as the structure, it is not limited to this. For example, the speed mode determination process may be performed for each page every time a certain time elapses, a plurality of print jobs are completed, a print job is completed, or a predetermined number of two or more sheets are printed.

(Modification 4) Overload detection may be performed even when the flag is “1” (low speed mode) during the initialization process.
(Modification 5) In the above-described embodiment, two speed modes, a high speed mode and a low speed mode, are provided. However, for the low speed mode, two or more speed modes (for example, the first low speed mode,..., The Nth low speed mode (N ≧ 2 natural number)). In this case, a plurality of threshold values for determining the magnitude of the overload are prepared, the magnitude of the overload is detected for each rank, and the overload is detected according to the detected overload magnitude among the plurality of speed modes. A larger speed is selected so that a lower speed mode is selected. According to this configuration, the speed mode corresponding to the magnitude of the overload is selected, so that although the overload is small, the speed is extremely low and the throughput is greatly reduced, or the overload is large. It is possible to more effectively avoid the inconvenience that the printing position accuracy is not lowered and the printing position accuracy is lowered, and it is possible to achieve both high throughput and high printing position accuracy.

  (Modification 6) When an overload is detected in the first paper feed, the next paper feed may be set to the low speed mode. In this case, the overload may be detected using the threshold value for the low speed mode in the next paper feeding process in the low speed mode.

  (Modification 7) If an overload is detected by one overload detection, the feeding speed may be changed to the low speed mode from the next time. Further, the number of times of continuous overload detection for determining the low speed mode may be a predetermined number of times of three or more.

  (Modification 8) Number of times of overload detection (speed mode determination process) when the detected load (number of interruptions K) exceeds the threshold value for paper jam larger than the threshold value Ks due to paper jam or the like of the paper supply You may make it not add to.

  (Modification 9) In the above embodiment, a configuration is adopted in which the subsequent sheet is preliminarily fed to a predetermined position (position near the intermediate roller) during the recording of the preceding sheet. However, the preliminary feeding may be abolished. Further, the inter-page control that feeds the same amount of the succeeding paper in parallel with the paper feeding of the preceding paper may be abolished in order to keep the space between the preceding paper and the following paper narrow.

  (Modification 10) Instead of being driven by the two driving sources of the ASF motor 23 and the PF motor 27, the feeding unit may be driven only by one driving source (PF motor 27).

(Modification 11) The recording method of the recording apparatus is not limited to the ink jet recording method, and a dot impact recording method, a thermal transfer recording method, a laser recording method, or the like can also be adopted.
(Modification 12) The present invention is not limited to a serial printer but can be applied to a line printer or a page printer. Line printers and page printers do not intermittently carry the paper during the recording operation like a serial printer, but perform printing on the paper being conveyed at a constant speed. In this case, a process in which the sheet is fed to a predetermined position slightly upstream in the feeding direction from the recording start position can be defined as a feeding process. Therefore, in the case of line printers and page printers as well, when the overload of the PF motor is detected during the paper feeding process and an overload is detected, the conveyance of the paper during the recording operation is detected. By adopting a lower speed mode corresponding to the load, it is possible to suppress a decrease in recording position accuracy due to an overload caused by a sliding resistance of the transport system.

  (Modification 13) The recording apparatus is not limited to a printer. The present invention can also be applied to other liquid ejecting type recording apparatuses that eject liquid other than ink. Here, “recording” includes not only recording by printing, but also recording in which a liquid material containing a material having a predetermined characteristic, for example, is jetted onto a circuit board as a recording medium so as to draw a wiring pattern, pixels, and the like. . For example, a liquid ejecting apparatus (recording apparatus) that ejects a liquid material in which materials such as electrode materials and color materials used for manufacturing liquid crystal displays, EL (electroluminescence) displays, and surface-emitting displays are dispersed or dissolved. Also good. For example, when a sheet-like substrate is sequentially fed one by one by a feeding unit, and a predetermined pattern is drawn on the fed substrate by a recording unit, the conveyance of the substrate is detected and a load applied to a driving source in the feeding process is detected. By performing in the speed mode according to the result, high recording position accuracy can be ensured while avoiding excessive power consumption of the drive source.

1 is a perspective view of a printer according to an embodiment. 6 is a graph showing a speed profile in paper feed processing. FIG. 4 is a schematic side cross-sectional view illustrating a front feeding device and a paper transport mechanism. FIG. 2 is a block diagram illustrating an electrical configuration of the printer. The timing chart which shows the conveyance speed control in case of (a) without overload and (b) with overload. 6 is a flowchart illustrating a printer initialization routine. The flowchart which shows a conveyance speed control routine. The flowchart which similarly shows a conveyance speed control routine.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 11 ... Printer as recording device, 14 ... Carriage constituting recording means, 16 ... CR motor constituting recording means, 17 ... Recording head constituting recording means, 22 ... Front feeding device as feeding means, 23 DESCRIPTION OF SYMBOLS ASF motor, 25 ... Rear feeding device as feeding means, 27 ... PF motor as drive source, 28 ... Conveying roller pair constituting conveying means, 29 ... Discharge roller pair constituting conveying means, 30 ... Linear Encoder, 35 ... pickup roller constituting feeding means, 36 ... intermediate roller constituting feeding means, 37 ... retard roller constituting feeding means, 40 ... swing member constituting feeding means, 41 ... transport Conveying drive roller constituting means, 42... Conveying driven roller constituting the conveying means, 43... Discharging driving roller constituting the conveying means, 44. Follow-up roller, 45 ... rear end sensor, 46 ... front end sensor, 47 ... paper detection sensor, 50 ... controller as control means, 52 ... sub motor constituting feed means, 53 ... power switch, 54, 55 ... encoder, 60: Control unit constituting control means 61: Head driver 62-65 Motor driver 66 66 Paper feed roller constituting feeding means 72 Head control part 73 Carriage control part 74 Control means PF control unit, 75 ... ASF control unit, 76 ... SM control unit, 77 ... nonvolatile memory as storage means, 78 ... memory, 81 ... timer, 82 ... overload detection counter, 83 ... mode setting unit, 84... Overload detector as detection means, 85... Interrupt counter constituting detection means, 86. Determination section constituting detection means, P. Paper, P1 ... previous sheet, P2 ... subsequent sheets, F ... flag, PT ... PF speed table, AT ... ASF speed table.

Claims (8)

A recording device for recording on a recording medium,
A feeding means for feeding a recording medium;
Conveying means for conveying the recording medium fed by the feeding means;
Recording means for recording on a recording medium conveyed by the conveying means;
A driving source common to the feeding means and the conveying means;
Detecting means for detecting an overload applied to the drive source in the process of feeding the recording medium;
When the overload is not detected by the detection means, the recording medium is conveyed by the conveyance means in the first speed mode. On the other hand, when the overload is detected, the conveyance of the recording medium is performed. Control means for controlling the drive source so that transport by means is performed in a second speed mode which is a speed mode lower than the first speed mode;
A recording apparatus comprising: The detection means detects the overload in a plurality of continuous feeding processes,
The control means, when the detection means continuously detects the overload multiple times, without causing the detection means to detect the overload in the feeding process after the next multiple times. The recording apparatus according to claim 1, wherein the recording medium is conveyed by the conveying unit in the second speed mode.   The control means detects the overload at another time after the one time among the plurality of times after the detection means detects the overload at one time among the plurality of times. If not, the recording medium is conveyed by the conveying means in the first speed mode without causing the detecting means to detect the overload in the feeding process after the next multiple times. The recording apparatus according to claim 1, wherein: The control means controls the drive source so as to feed the recording medium in the first speed mode in the feeding process when the overload is detected;
When the detecting means detects the plurality of overloads continuously, the control means is configured to perform feeding in the feeding process after the next multiple times in the second speed mode. The recording apparatus according to claim 1, wherein the recording apparatus is controlled.   The control unit controls the drive source so that at least the conveyance by which the recording unit determines the recording position with respect to the recording medium among the plurality of types of conveyance performed by the conveyance unit is performed in the second speed mode. The recording apparatus according to any one of claims 1 to 4. Storage means for storing a speed mode determined based on the detection result of the detection means;
If the speed mode read from the storage means when the recording apparatus is powered on is the second speed mode, the control means drives the drive source and performs the detection in an initialization process when the power is turned on. Means for detecting an overload of the drive source, and when the detection means detects an overload, the drive source is set to perform at least the conveyance of the recording medium after the power is turned on in the second speed mode. The recording apparatus according to claim 1, wherein the recording apparatus is controlled. When the control means is the first speed mode, the speed mode read from the storage means when the recording device is powered on,
The detection means detects an overload of the drive source during the feeding process of the recording medium performed after the power is turned on,
The recording apparatus according to claim 6, wherein when the detection unit detects an overload, the drive source is controlled so that at least the conveyance of the recording medium is performed in the second speed mode. A feeding means for feeding a recording medium;
Conveying means for conveying the recording medium fed by the feeding means;
Recording means for recording on the medium conveyed by the conveying means;
A conveying method in a recording apparatus comprising a driving source common to the feeding means and the conveying means,
A detection step of detecting an overload of the drive source in the process of feeding the recording medium performed by driving the drive source and operating the feeding means;
When the overload is not detected, the recording medium is transported by the transport means in the first speed mode. On the other hand, when the overload is detected, the recording medium is transported by the transport means. A control step of controlling the drive source to perform in a second speed mode, which is a speed mode lower than the first speed mode;
A medium conveying method in a recording apparatus.

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