JP3885559B2 - Printer control method and printer control apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printer control method and a printer control apparatus, and more particularly to a printer control method for controlling the speed of a paper feed motor when printing paper bites on a paper feed roller and a driven roller during paper feed operations in a printer. And a printer control apparatus. The present invention also relates to a recording medium on which a computer program for executing the printer control method is recorded.
[0002]
[Prior art]
FIG. 12 is an explanatory diagram schematically showing a configuration of a portion related to feeding of printing paper and detection of the upper and lower edges of the printing paper in the printer.
[0003]
In the printer, as shown in FIG. 12, when the printing paper 50 set on the tray 90 is fed out one by one by the paper feed roller 64, the upper end of the printing paper 50 is detected by the paper detection sensor 15. A paper feed motor 63 (see FIG. 8) is connected to the paper feed roller 64, and the paper feed roller 64 is driven by controlling the drive of the paper feed motor 63 to feed paper into the printer.
[0004]
Thereafter, the printing paper 50 is fed by a paper feeding roller 65 and a driven roller 66, and printing is performed by ink ejected from the printing head 9 on the platen 84. When printing proceeds to the vicinity of the lower end of the printing paper 50 and the printing paper 50 is sequentially fed, the printing paper 50 does not exist on the paper detection sensor 15 at a certain point in time. Detected.
[0005]
The paper feeding operation into the printer is generally performed as described above. In this paper feeding operation, when the printing paper is stuck against the paper feed motor and the driven roller, the printing paper is It is desirable that the upper end of the paper is sandwiched in parallel with the paper feed motor and the driven roller.
[0006]
However, in actuality, when the printing paper bites, the upper end of the printing paper is not completely parallel to the paper feed motor and the driven roller, and is often sandwiched slightly obliquely.
[0007]
Therefore, after biting the printing paper, the printing paper sandwiched between the paper feed motor and the driven roller is sent in the opposite direction and pushed back, so-called discharge is performed, and the printing paper is repeated several times. The upper end of the printing paper is completely parallel to the paper feed motor and the driven roller, and the skew of the printing paper is removed. The printing paper skew removal operation will be described in detail below with reference to the drawings.
[0008]
FIG. 13 is an explanatory diagram schematically showing a state viewed from the side of the paper feed roller, paper feed roller, and printing paper when the printing paper is skewed, and FIG. 14 is a drawing when the printing paper is skewed. It is explanatory drawing which showed typically the state seen from the upper surface side of the paper supply roller, the paper feed roller, and the printing paper.
[0009]
As shown in FIG. 13A and FIG. 14A, when the printing paper 50 is fed out one by one by the paper feed roller 64, the upper end of the printing paper 50 gradually moves toward the paper as the paper feeding roller 64 rotates. It approaches the feed roller 65 and the driven roller 66. At this time, it is desirable that the upper end of the printing paper 50 be parallel to the paper feed roller 65 and the driven roller 66, but it may be slightly inclined as shown in FIG.
[0010]
As shown in FIGS. 13B and 14B, when the paper feed roller 64 further rotates, the upper end portion of the printing paper 50 abuts against the paper feed roller 65 and the driven roller 66 and is sandwiched. As described above, this is called printing paper biting.
[0011]
In order to remove the skew of the printing paper, the paper feed roller 64 stops when it rotates by a predetermined amount. At this time, the length of the upper end portion of the printing paper that protrudes to the inside of the printer from the nipping position of the printing paper 50 by the paper feeding roller 65 and the driven roller 66 is referred to as a biting amount C. This biting amount C is normally set for each type of printing paper 50 and can be changed by setting the printer according to the type of printing paper 50. 13B and 14B show a case where the printing paper 50 strikes the paper feeding roller 65 and the driven roller 66 obliquely, and therefore the biting amount C is almost equal to that of the printing paper 50. The amount of biting in the center is shown.
[0012]
Next, as shown in FIGS. 13C and 14C, the paper feed roller 65 is rotated in the reverse direction with the paper feed roller 64 stopped to perform the skew removal of the print paper 50, and printing is performed. The paper 50 is fed backward by the biting amount C and discharged. The printing paper 50 that has been reversely fed by the biting amount C and discharged is bent, and the upper end of the printing paper 50 is pressed against the paper feed roller 65 and the driven roller 66 by the elasticity of the printing paper itself. At this time, the upper end of the printing paper 50 is substantially parallel to the paper feed roller 65 and the driven roller 66.
[0013]
In a state where the upper end of the printing paper 50 is substantially parallel to the paper feed roller 65 and the driven roller 66, the paper feed roller 65 is bitten within the range of the amount C as shown in FIGS. 13 (d) and 14 (d). The upper end of the printing paper 50 is bitten by the paper feed roller 65 and the driven roller 66. 13 (d) and FIG. 14 (d) and the discharge shown in FIG. 13 (c) and FIG. 14 (c) are repeated several times, so that the upper end of the printing paper 50 becomes the paper feed roller. 65 and the driven roller 66 are parallel to each other.
[0014]
When the upper end of the printing paper 50 is in a state parallel to the paper feeding roller 65 and the driven roller 66, the paper feeding roller 65 is rotated in the forward direction so that the printing paper 50 is fed back to the paper feeding roller 65 and the driven roller 66 again. At the same time, the paper feed roller 64 is rotated to release the printing paper 50, and the subsequent paper feeding operation is performed. The above is the operation for skew removal of printing paper.
[0015]
Next, speed control of the paper feed motor from when the paper feed roller starts the paper feed operation to when it stops for skewing of the print paper will be described.
[0016]
FIG. 15 shows a first example of the target speed of the paper feed motor, the current speed, and the waveform of the control signal from when the paper feed roller starts the paper feed operation to when it stops for deskewing the printing paper. It is a graph. FIG. 16 is a graph in which the section from the remaining distance 300 to 0 to the target stop position in the graph of FIG. 15 is enlarged only on the horizontal axis.
[0017]
The target stop position in FIGS. 15 and 16 is a position where the upper end of the printing paper is bitten by the paper feed roller 65 and the driven roller 66 by a predetermined biting amount C, and the paper feed roller 64 is stopped for deskewing the printing paper. It is.
[0018]
The remaining distance from the target stop position 800 (1/1440 inch (1 inch = 2.54 cm); hereinafter, units are omitted as appropriate) to 700 has a PID waveform displayed, but in the PID control section It is an acceleration control section, and acceleration is performed toward the target speed Vref in the constant speed section from the remaining distance 700 to 300.
[0019]
PID control is started when a constant speed section from the remaining distance 700 to 300 is entered, and thereafter, PID control is performed until the paper feed motor is stopped to stop the paper feed roller 64 at the target stop position. In this section, PID control is performed to converge the overshoot and undershoot of the current speed Vcur with respect to the target speed Vref.
[0020]
From around the remaining distance 300, deceleration control of the target speed Vref is gradually started, and from the remaining distance 200, more rapid deceleration control is performed.
[0021]
Incidentally, an undershoot of the current speed Vcur occurs in the deceleration control section between the remaining distances 200 and 100. This is because the upper end of the printing paper hits the paper feed roller 65 and the driven roller 66. This is because the current speed Vcur has temporarily decreased rapidly.
[0022]
Then, since PID control is performed in this section, a PID command value for commanding acceleration is output in order to reduce the difference between the target speed Vref and the current speed Vcur in this undershoot section.
[0023]
However, while the paper feed motor is accelerated according to the PID command value, the target speed Vref decreases during that time, so in the interval from the remaining distance 100 to 20, the current speed Vcur is exceeded. A shoot has occurred.
[0024]
This time, a PID command value for instructing deceleration is output in order to reduce the difference between the target speed Vref and the current speed Vcur in this overshoot period by PID control.
[0025]
As a result, although the overshoot of the current speed Vcur converges at a position around the remaining distance 20, an undershoot of the current speed Vcur occurs again in the section from the remaining distance 20 to 5.
[0026]
Therefore, in order to reduce the difference between the target speed Vref and the current speed Vcur in the undershoot section, a PID command value for instructing acceleration is output and the current speed Vcur substantially coincides with the target speed Vref, and then decelerates according to the target speed Vref. Is output, the current speed Vcur becomes 0 at the target stop position, and the paper feed motor and paper feed roller stop.
[0027]
[Problems to be solved by the invention]
The speed control of the paper feed motor from when the paper feed roller starts the paper feed operation to when it stops for skewing of the print paper is as described above, but the upper end of the print paper is the paper feed roller 65 and the follower. The size and length of the undershoot and overshoot of the current speed Vcur generated by striking the roller 66 vary depending on the type of printing paper and the angle between the upper end of the printing paper and the paper feed roller and driven roller.
[0028]
Depending on the size and length of the undershoot and overshoot of the current speed Vcur, the current speed Vcur becomes 0 before reaching the target stop position, and the paper feed motor and the printing paper are stopped. was there. Hereinafter, this problem will be specifically described with reference to the drawings.
[0029]
FIG. 17 shows a second example of the target speed of the paper feed motor, the current speed, and the waveform of the control signal from when the paper feed roller starts the paper feed operation to when it stops for deskewing the printing paper. It is a graph. FIG. 18 is a graph in which the section from the remaining distance 300 to 0 to the target stop position in the graph of FIG. 17 is enlarged only on the horizontal axis.
[0030]
The deceleration control of the target speed Vref is gradually started from around the remaining distance 300, and more rapid deceleration control is performed from the remaining distance 200. During the remaining distance 200 to 80 in this deceleration control section, An undershoot of the current speed Vcur occurs due to the upper end of the printing paper hitting the paper feed roller 65 and the driven roller 66.
[0031]
Then, since PID control is performed in this section, a PID command value for commanding acceleration is output in order to reduce the difference between the target speed Vref and the current speed Vcur in this undershoot section.
[0032]
However, while the paper feed motor is accelerated according to the PID command value, the target speed Vref also decreases during that time. Therefore, in the section from the remaining distance 80 to 15, the current speed Vcur is exceeded. A shoot has occurred.
[0033]
This time, a PID command value for instructing deceleration is output in order to reduce the difference between the target speed Vref and the current speed Vcur in this overshoot period by PID control.
[0034]
As a result, although the overshoot of the current speed Vcur converges at a position around the remaining distance 15, an undershoot of the current speed Vcur occurs again in the section from the remaining distance 15 to 5.
[0035]
Accordingly, in order to reduce the difference between the target speed Vref and the current speed Vcur in the undershoot section, a PID command value for instructing acceleration is output and the current speed Vcur coincides with the target speed Vref almost at the target stop position. The current speed Vcur becomes 0, and the paper feed motor and paper feed roller are stopped.
[0036]
Although the waveform of the current speed Vcur is obtained when the printing paper reaches the target stop position, the current speed Vcur is temporarily almost completely zero at the remaining distance 10 position. Accordingly, if the undershoot of the current speed Vcur in the section from the remaining distance 15 to 5 is still a little larger, the current speed Vcur will be completely zero, the acceleration command by PID control will not be in time, and the printing paper will not be in time. Stops halfway without reaching the target stop position.
[0037]
Such a problem may occur in the paper feed motor control by the conventional printer control method and printer control apparatus.
[0038]
The present invention has been made in view of the above-described problems, and its purpose is that the paper feed roller starts the paper feeding operation until it stops for skewing of the printing paper, that is, the upper end of the printing paper is placed on the paper. In the speed control of the paper feed motor until it stops in the state of being sandwiched between the feed roller and the driven roller, printing due to the undershoot of the paper feed motor speed waveform due to the contact with the paper feed roller and the driven roller at the upper end of the print paper It is an object of the present invention to provide a printer control method and a printer control apparatus having a configuration capable of preventing a paper stoppage in advance.
[0039]
[Means for Solving the Problems]
According to the printer control method of the present invention, after the paper feed roller starts the paper feed operation, the paper feed roller and the driven roller pass the upper end of the print paper and then the upper end of the print paper is moved to the paper feed roller and In the speed control of the paper feed motor until it stops in the state of being sandwiched between the driven rollers, the current speed of the paper feed motor is rapidly reduced due to the abutting of the upper end of the printing paper against the paper feed roller and the driven roller. In this case, the target speed is changed discontinuously to such an extent that an undershoot of the current speed with respect to the target speed of the paper feed motor is avoided.
[0041]
According to the printer control device of the present invention, after the paper feeding roller starts the paper feeding operation, the paper feeding roller and the driven roller are abutted against the upper edge of the printing paper and then the upper edge of the printing paper is moved to the paper feeding roller and In the speed control of the paper feed motor until it stops in the state of being sandwiched between the driven rollers, the current speed of the paper feed motor is rapidly reduced due to the abutting of the upper end of the printing paper against the paper feed roller and the driven roller. In this case, a target speed calculation unit that discontinuously changes the target speed to the extent that generation of an undershoot of the current speed with respect to the target speed of the paper feed motor is avoided is provided.
[0043]
With the above configuration, the printer control method and printer control device according to the present invention can rapidly reduce the target speed of the paper feed motor, and the current speed due to the upper end of the print paper hitting the paper feed roller and the driven roller. Generation of undershoot with respect to the target speed can be avoided, and output of a command value for instructing acceleration in the deceleration process can be prevented. As a result, subsequent overshoots and undershoots can be prevented from occurring in a chain, so that there is no significant disturbance in the current speed and control signal waveforms, and before the printing paper reaches the target stop position. It is possible to completely avoid the situation of stopping on the way.
[0044]
According to the computer program recording medium of the present invention, a computer program for executing the printer control method of the present invention in the computer system is recorded.
[0045]
DETAILED DESCRIPTION OF THE INVENTION
First, a schematic configuration and control method of an ink jet printer, which is a main application target of the printer control method and printer control apparatus according to the present invention, will be described.
[0046]
FIG. 4 is a block diagram showing a schematic configuration of the ink jet printer.
[0047]
The ink jet printer shown in FIG. 4 discharges ink onto a paper feed motor (hereinafter also referred to as a PF motor) 1 that feeds paper, a paper feed motor driver 2 that drives the paper feed motor 1, and printing paper 50. The head 9 is fixed, the carriage 3 is driven in a direction parallel to the printing paper 50 and perpendicular to the paper feeding direction, a carriage motor (hereinafter also referred to as a CR motor) 4 for driving the carriage 3, and a carriage motor. 4, a DC motor 6 that delivers a direct current command value to the CR motor driver 5, a pump motor 7 that controls the suction of ink to prevent clogging of the head 9, and a pump motor 7 Motor driver 8 for driving the head, head driver 10 for driving and controlling the head 9, and linear type fixed to the carriage 3 A encoder 11, a code plate 12 for a linear encoder 11 having slits formed at predetermined intervals, a rotary encoder 13 for the PF motor 1, and a paper detection sensor 15 for detecting the end position of the paper being printed. A CPU 16 that controls the entire printer, a timer IC 17 that periodically generates an interrupt signal to the CPU 16, and an interface unit (hereinafter also referred to as IF) 19 that transmits and receives data to and from the host computer 18. The ASIC 20 for controlling the print resolution, the drive waveform of the head 9 and the like based on the print information sent from the host computer 18 through the IF 19, and the PROM 21 and RAM 22 used as work areas and program storage areas of the ASIC 20 and the CPU 16. And the EEPROM 23 and the plastic paper 50 supporting the printing paper 50 25, a transport roller 27 that is driven by the PF motor 1 to transport the printing paper 50, a pulley 30 that is attached to the rotating shaft of the CR motor 4, and a timing belt 31 that is driven by the pulley 30. Yes.
[0048]
The DC unit 6 drives and controls the paper feed motor driver 2 and the CR motor driver 5 based on the control command sent from the CPU 16 and the outputs of the encoders 11 and 13. Further, both the paper feed motor 1 and the CR motor 4 are constituted by DC motors.
[0049]
FIG. 5 is a perspective view showing a configuration around the carriage 3 of the ink jet printer.
[0050]
As shown in FIG. 5, the carriage 3 is connected to the carriage motor 4 via the pulley 30 by the timing belt 31, and is driven so as to move parallel to the platen 25 while being guided by the guide member 32. A recording head 9 having a nozzle row for ejecting black ink and a nozzle row for ejecting color ink is provided on the surface of the carriage 3 facing the printing paper, and each nozzle is supplied with ink from the ink cartridge 34 for printing. Characters and images are printed by ejecting ink droplets on paper.
[0051]
Further, in the non-printing area of the carriage 3, a capping device 35 for sealing the nozzle openings of the recording head 9 at the time of non-printing and a pump unit 36 having the pump motor 7 shown in FIG. 4 are provided. . When the carriage 3 moves from the printing area to the non-printing area, the carriage 3 comes into contact with a lever (not shown), the capping device 35 moves upward, and the head 9 is sealed.
[0052]
When the nozzle opening row of the head 9 is clogged or when the ink is forcibly ejected from the head 9 by replacing the cartridge 34 or the like, the pump unit 36 is operated with the head 9 sealed. The ink is sucked out from the nozzle opening row by the negative pressure from the pump unit 36. As a result, dust and paper dust adhering to the vicinity of the nozzle opening row are washed, and air bubbles in the head 9 are discharged to the cap 37 together with ink.
[0053]
FIG. 6 is an explanatory diagram schematically showing the configuration of the linear encoder 11 attached to the carriage 3.
[0054]
The encoder 11 shown in FIG. 6 includes a light emitting diode 11a, a collimator lens 11b, and a detection processing unit 11c. The detection processing unit 11c includes a plurality (four) of photodiodes 11d, a signal processing circuit 11e, and two comparators 11fA and 11fB.
[0055]
When the voltage VCC is applied across the light emitting diode 11a via a resistor, light is emitted from the light emitting diode 11a. This light is condensed into parallel light by the collimator lens 11 b and passes through the code plate 12. The code plate 12 is provided with slits at predetermined intervals (for example, 1/180 inch (1 inch = 2.54 cm)).
[0056]
The parallel light that has passed through the code plate 12 enters each photodiode 11d through a fixed slit (not shown) and is converted into an electrical signal. The electric signals output from the four photodiodes 11d are processed in the signal processing circuit 11e, the signals output from the signal processing circuit 11e are compared in the comparators 11fA and 11fB, and the comparison result is output as a pulse. Pulses ENC-A and ENC-B output from the comparators 11fA and 11fB are output from the encoder 11.
[0057]
FIG. 7 is a timing chart showing waveforms of two output signals of the encoder 11 at the time of forward rotation and reverse rotation of the CR motor.
[0058]
As shown in FIGS. 7A and 7B, the phase of the pulse ENC-A and the pulse ENC-B differ by 90 degrees in both cases of CR motor forward rotation and reverse rotation. When the CR motor 4 is rotating forward, that is, when the carriage 3 is moving in the main scanning direction, the pulse ENC-A is 90 degrees from the pulse ENC-B, as shown in FIG. When the phase is advanced only by the time and the CR motor 4 is reversely rotated, the encoder 4 is configured so that the phase of the pulse ENC-A is delayed by 90 degrees from the pulse ENC-B, as shown in FIG. ing. One period T of the pulse corresponds to the slit interval (for example, 1/180 inch) of the code plate 12, and is equal to the time for the carriage 3 to move the slit interval.
[0059]
On the other hand, the rotary encoder 13 for the PF motor 1 has the same configuration as that of the linear encoder 11 except that the code plate is a rotating disc that rotates in accordance with the rotation of the PF motor 1, and has two output pulses. ENC-A and ENC-B are output. In the ink jet printer, the slit interval of the plurality of slits provided on the code plate of the rotary encoder 13 for the PF motor 1 is 1/180 inch, and when the PF motor 1 rotates by the 1 slit interval, 1 / The paper is fed by 1440 inches.
[0060]
FIG. 8 is a perspective view showing portions related to paper feeding and paper detection.
The position of the paper detection sensor 15 shown in FIG. 4 will be described with reference to FIG. In FIG. 8, the printing paper 50 inserted into the paper feed insertion slot 61 of the printer 60 is sent into the printer 60 by a paper feed roller 64 driven by a paper feed motor 63. The leading edge of the printing paper 50 fed into the printer 60 is detected by, for example, the optical paper detection sensor 15. The paper 50 whose leading edge is detected by the paper detection sensor 15 is fed by the paper feed roller 65 and the driven roller 66 driven by the PF motor 1.
[0061]
Subsequently, printing is performed by dropping ink from a recording head (not shown) fixed to the carriage 3 that moves along the carriage guide member 32. When the paper is fed to a predetermined position, the end of the currently printed printing paper 50 is detected by the paper detection sensor 15. The printed paper 50 that has been printed is discharged from the paper discharge port 62 to the outside by the paper discharge roller 68 and the driven roller 69 driven by the gear 67C via the gears 67A and 67B driven by the PF motor 1. A rotary encoder 13 is connected to the rotation shaft of the paper feed roller 65.
[0062]
FIG. 9 is a perspective view showing in detail a portion related to paper feeding of the printer.
[0063]
A portion related to paper feeding in the printer portion shown in FIG. 8 will be described in more detail with reference to FIGS.
[0064]
When the leading edge of the printing paper 50 inserted through the paper feed insertion port 61 of the printer 60 and fed into the printer 60 by the paper feed roller 64 is detected by the paper detection sensor 15, the PF motor 1 passes through the small gear 87. A paper feed roller 65 provided around a smap shaft 83 that is a rotation shaft of the driven large gear 67a and a holder 89 that presses the printing paper 50 fed from the paper feeding side downward in the vertical direction. The printing paper 50 is fed by a driven roller 66 provided at the front end of the paper feeding direction on the paper discharge side.
[0065]
The PF motor 1 is fixed to a frame 86 in the printer 60 with screws 85, a rotary encoder 13 is disposed at a predetermined location around the large gear 67a, and a smap shaft 83 which is a rotation shaft of the large gear 67a. A rotary encoder code plate 14 is connected to the encoder.
[0066]
The printing paper 50 that has been fed by the paper feeding roller 65 and the driven roller 66 passes over the platen 84 that supports the printing paper 50, and the small gear 87, the large gear 67 a, the intermediate gear 67 b, the small gear 88, and the like. The paper is fed between a paper discharge roller 68 driven by the PF motor 1 via a paper discharge gear 67c and a serrated roller 69 as a driven roller, and is fed to the outside through a paper discharge port 62.
[0067]
While the printing paper 50 is supported on the platen 84, the carriage 3 moves left and right along the guide member 32 in the space on the platen 84, and ink is ejected from a recording head (not shown) fixed to the carriage 3. Is discharged and printing is performed.
[0068]
Next, a configuration of a DC unit 6 that is a conventional DC motor control device that controls the CR motor 4 of the above-described inkjet printer, and a control method by the DC unit 6 will be described.
[0069]
FIG. 10 is a block diagram showing a configuration of a DC unit 6 which is a conventional DC motor control device, and FIG. 11 is a graph showing a motor current and a motor speed of the CR motor 4 controlled by the DC unit 6. is there.
[0070]
The DC unit 6 shown in FIG. 10 includes a position calculator 6a, a subtractor 6b, a target speed calculator 6c, a speed calculator 6d, a subtractor 6e, a proportional element 6f, an integral element 6g, a differential It comprises an element 6h, an adder 6i, a D / A converter 6j, a timer 6k, and an acceleration controller 6m.
[0071]
The position calculator 6a detects the rising edge and the falling edge of each of the output pulses ENC-A and ENC-B of the encoder 11, counts the number of detected edges, and based on the counted value, the carriage 3 The position of is calculated. This count is incremented by “+1” when one edge is detected when the CR motor 4 is rotating in the forward direction, and “−1” when one edge is detected when the CR motor 4 is rotating in the reverse direction. Is added. The period of each of the pulses ENC-A and ENC-B is equal to the slit interval of the code plate 12, and the phase of the pulse ENC-A and the pulse ENC-B differ by 90 degrees. Therefore, the count value “1” of the count corresponds to ¼ of the slit interval of the code plate 12. Thus, if the count value is multiplied by 1/4 of the slit interval, the amount of movement from the position of the carriage 3 corresponding to the count value “0” can be obtained. At this time, the resolution of the encoder 11 is ¼ of the interval between the slits of the code plate 12. If the interval between the slits is 1/180 inch, the resolution is 1/720 inch.
[0072]
The subtractor 6b calculates a position deviation between the target position sent from the CPU 16 and the actual position of the carriage 3 obtained by the position calculation unit 6a.
[0073]
The target speed calculator 6c calculates the target speed of the carriage 3 based on the position deviation that is the output of the subtractor 6b. This calculation is performed by multiplying the position deviation by the gain KP. This gain KP is determined according to the position deviation. Note that the value of the gain KP may be stored in a table (not shown).
[0074]
The speed calculator 6 d calculates the speed of the carriage 3 based on the output pulses ENC-A and ENC-B of the encoder 11. This speed is obtained as follows. First, the rising edge and the falling edge of each of the output pulses ENC-A and ENC-B of the encoder 11 are detected, and the time interval between edges corresponding to 1/4 of the slit interval of the code plate 12 is determined by a timer counter. Count. If this count value is T and the slit interval of the code plate 12 is λ, the carriage speed can be obtained as λ / (4T). Here, the calculation of the speed is obtained by measuring one cycle of the output pulse ENC-A, for example, from the rising edge to the next rising edge with a timer counter.
[0075]
The subtractor 6e calculates a speed deviation between the target speed and the actual speed of the carriage 3 calculated by the speed calculation unit 6d.
[0076]
The proportional element 6f multiplies the speed deviation by a constant Gp and outputs the multiplication result. The integration element 6g integrates the speed deviation multiplied by a constant Gi. The differentiation element 6h multiplies the difference between the current speed deviation and the previous speed deviation by a constant Gd, and outputs the multiplication result. The calculation of the proportional element 6f, the integral element 6g, and the derivative element 6h is performed in synchronization with the rising edge of the output pulse ENC-A, for example, for each cycle of the output pulse ENC-A of the encoder 11.
[0077]
The outputs of the proportional element 6f, the integral element 6g, and the derivative element 6h are added by the adder 6i. Then, the addition result, that is, the driving current of the CR motor 4 is sent to the D / A converter 6j and converted into an analog current. The CR motor 4 is driven by the driver 5 based on the analog voltage.
[0078]
The timer 6k and the acceleration control unit 6m are used for acceleration control, and the PID control using the proportional element 6f, the integral element 6g, and the derivative element 6h is used for constant speed and deceleration control during acceleration.
[0079]
The timer 6k generates a timer interrupt signal every predetermined time based on the clock signal sent from the CPU 16.
[0080]
Each time the acceleration control unit 6m receives the timer interrupt signal, the acceleration control unit 6m integrates a predetermined current value (for example, 20 mA) to the target current value, and the integration result, that is, the target current value of the DC motor 4 during acceleration is D / A is sent to the A converter 6j. As in the case of PID control, the target current value is converted into an analog current by the D / A converter 6j, and the CR motor 4 is driven by the driver 5 based on this analog current.
[0081]
The driver 5 includes, for example, four transistors, and (a) an operation mode in which the CR motor 4 is rotated forward or reverse by turning each of the transistors on or off based on the output of the D / A converter 6j. b) Regenerative brake operation mode (short brake operation mode, i.e., mode in which the CR motor is stopped) and (c) mode in which the CR motor is to be stopped can be performed.
[0082]
Next, the operation of the DC unit 6, that is, a conventional DC motor control method will be described with reference to FIGS. 11 (a) and 11 (b).
[0083]
When the start command signal for starting the CR motor 4 is sent from the CPU 16 to the DC unit 6 when the CR motor 4 is stopped, the start initial current value I0 is sent from the acceleration control unit 6m to the D / A converter 6j. It is done. This starting initial current value I0 is sent from the CPU 16 to the acceleration control unit 6m together with the starting command signal. The current value I0 is converted to an analog voltage by the D / A converter 6j and sent to the driver 5, and the CR motor 4 starts to be started by the driver 5 (see FIGS. 11A and 11B). After receiving the start command signal, a timer interrupt signal is generated from the timer 6k every predetermined time. Each time the acceleration control unit 6m receives a timer interrupt signal, the acceleration control unit 6m adds a predetermined current value (for example, 20 mA) to the startup initial current value I0, and sends the integrated current value to the D / A converter 6j. Then, the integrated current value is converted into an analog current by the D / A converter 6j and sent to the driver 5. Then, the CR motor is driven by the driver 5 and the speed of the CR motor 4 is increased so that the value of the current supplied to the CR motor 4 becomes the integrated current value (see FIG. 11B). For this reason, the current value supplied to the CR motor 4 is stepped as shown in FIG. At this time, the PID control system is also operating, but the D / A converter 6j selects and takes in the output of the acceleration control unit 6m.
[0084]
The integration process of the current value of the acceleration control unit 6m is performed until the integrated current value becomes a constant current value IS. When the current value integrated at time t1 reaches a predetermined value IS, the acceleration control unit 6m stops the integration process and supplies a constant current value IS to the D / A converter 6j. Thus, the driver 5 is driven so that the value of the current supplied to the CR motor 4 becomes the current value IS (see FIG. 11A).
[0085]
In order to prevent the speed of the CR motor 4 from overshooting, when the CR motor 4 reaches a predetermined speed V1 (see time t2), acceleration control is performed so as to reduce the current supplied to the CR motor 4. The unit 6m controls. At this time, the speed of the CR motor 4 further increases, but when the speed of the CR motor 4 reaches a predetermined speed Vc (see time t3 in FIG. 11B), the D / A converter 6j outputs the output of the PID control system. That is, the output of the adder 6i is selected and PID control is performed.
[0086]
That is, the target speed is calculated based on the position deviation between the target position and the actual position obtained from the output of the encoder 11, and based on the speed deviation between the target speed and the actual speed obtained from the output of the encoder 11. Thus, the proportional element 6f, the integral element 6g, and the differential element 6h operate to perform proportional, integral, and differential calculations, respectively, and the CR motor 4 is controlled based on the sum of these calculation results. The proportional, integral and differential calculations are performed in synchronization with the rising edge of the output pulse ENC-A of the encoder 11, for example. As a result, the speed of the DC motor 4 is controlled to a desired speed Ve. The predetermined speed Vc is preferably 70 to 80% of the desired speed Ve.
[0087]
Since the DC motor 4 has a desired speed from time t4, the carriage 3 also has a desired constant speed Ve, and printing processing can be performed.
[0088]
When the printing process is finished and the carriage 3 approaches the target position (see time t5 in FIG. 11B), the position deviation becomes small and the target speed also becomes small. Therefore, the speed deviation, that is, the output of the subtractor 6e is obtained. It becomes negative, the DC motor 4 is decelerated, and stops at time t6.
[0089]
The content of the drive control when the DC motor is the CR motor 4 has been described above, but the content of the drive control is substantially the same when the DC motor is the paper feed motor (PF motor) 1 or the paper feed motor. It will be a thing.
[0090]
DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, an embodiment of a printer control method and a printer control device according to the invention will be described with reference to the drawings.
[0091]
FIG. 1 is a graph showing the target speed and actual motor speed of the paper feed motor controlled by the printer control method and printer control apparatus according to the present invention, and the waveforms of the control signals.
[0092]
The printer control method and the printer control apparatus according to the present invention provide a period from when a paper feed roller starts a paper feed operation until it stops for skewing of the print paper, that is, a print paper to the paper feed roller and its driven roller. In the speed control of the paper feed motor until the top edge of the printing paper stops after being stuck at the paper feed roller and its driven roller after the end of the top edge, the target speed at the start of deceleration is changed discontinuously. It has a characteristic.
[0093]
In the conventional printer control method and printer control apparatus, the target speed after the start of PID control in the speed control of the paper feed motor after the paper feed roller starts the paper feed operation until it stops for skewing of the print paper Was supposed to change continuously. Therefore, when the upper end of the printing paper hits the paper feed roller 65 and the driven roller 66, when the current speed Vcur decreases temporarily and rapidly, an undershoot of the current speed Vcur occurs almost certainly. If this undershoot is to be compensated for by PID control, an overshoot will occur on the contrary, and if this overshoot is to be compensated for by PID control, an undershoot will occur again and the printing paper may stop halfway. Invite the situation.
[0094]
Therefore, in order to prevent the problem that the printing paper is stopped halfway, it is necessary to avoid the occurrence of an undershoot of the current speed Vcur due to the contact of the upper end of the printing paper with the paper feed roller 65 and the driven roller 66. . If the target speed after the start of PID control is continuously changed as in the conventional printer control method and printer control apparatus, it is extremely difficult to avoid the occurrence of this undershoot.
[0095]
Therefore, in the printer control method and printer control apparatus according to the present invention, the target speed at the start of deceleration under PID control that is feedback control is changed discontinuously.
[0096]
With reference to the graph of FIG. 1, the speed control of the paper feed motor by the printer control method and printer control apparatus according to the present invention will be described in detail.
[0097]
The target stop position in FIG. 1 is a position where the upper end of the printing paper is bitten by the paper feed roller 65 and the driven roller 66 by a predetermined biting amount C, and the paper feeding roller 64 stops for skewing of the printing paper.
[0098]
The remaining distance from the target stop position 800 (1/1440 inch (1 inch = 2.54 cm); hereinafter, units are omitted as appropriate) to 700 has a PID waveform displayed, but in the PID control section It is an acceleration control section, and acceleration is performed toward the target speed Vref in the constant speed section from the remaining distance 700 to 300.
[0099]
PID control is started when a constant speed section from the remaining distance 700 to 200 is entered, and thereafter, PID control is performed until the paper feed motor is stopped to stop the paper feed roller 64 at the target stop position. In this section, PID control is performed to converge the overshoot and undershoot of the current speed Vcur with respect to the target speed Vref.
[0100]
Then, the deceleration control is started from the remaining distance 200. In the printer control method and the printer control apparatus according to the present invention, as shown in FIG. 1, the target at the start of deceleration under PID control is shown. The speed Vref is changed discontinuously.
[0101]
Thus, by changing the target speed Vref discontinuously, the target speed Vref can be drastically reduced, and the target of the current speed Vcur due to the upper end of the printing paper hitting the paper feed roller 65 and the driven roller 66. The occurrence of undershoot with respect to the speed Vref can be avoided. That is, even if the current speed Vcur suddenly decreases suddenly due to the contact of the printing paper, if the target speed Vref decreases more than that, the temporarily decreased portion of the current speed Vcur is under the target speed Vref. It is not a shoot. Here, if undershoot does not occur, the PID command value for commanding acceleration is not output.
[0102]
As a result, subsequent overshoots and undershoots are also prevented from occurring in a chain, so that the current speed Vcur and the PID control signal waveforms are not significantly disturbed as shown in FIG. The situation where the paper stops halfway before reaching the target stop position can be completely avoided.
[0103]
The size of the undershoot of the current speed Vcur generated by the contact of the printing paper varies depending on the type of printing paper, the angle between the printing paper upper end, the paper feed roller, and the driven roller, and the like. In general, the thicker the printing paper, the larger the undershoot at the current speed Vcur. The closer the print paper upper end, the paper feed roller, and the driven roller are in parallel, the smaller the undershoot at the current speed Vcur is. growing. Also, the larger the width of the printing paper, the larger the size of the undershoot of the current speed Vcur, and the printing paper thicker than the setting of the printing paper thickness is used, or two or more printing papers are accidentally double fed. In such a case, the undershoot of the current speed Vcur increases.
[0104]
Therefore, when the target speed Vref is changed discontinuously, the target speed Vref is discontinuously enough to cope with the maximum undershoot that can occur, considering various conditions. It should be reduced. For example, the value of the target speed Vref may be decreased instantaneously at the same time as the start of deceleration by about 10% of the value of the target speed Vref immediately before the start of deceleration.
[0105]
Setting where the amount of biting C of the printing paper at the target stop position where the paper feeding roller 64 stops for skewing of the printing paper is set to be large, that is, the printing paper hits before the deceleration starts. In this case, the effect of applying the configuration of the printer control method and printer control device according to the present invention is not so great.
[0106]
The printer control method and the printer control apparatus according to the present invention are more effective when the setting is such that the printing paper hits after the start of deceleration under PID control as in the present embodiment. Can be obtained.
[0107]
The printer control apparatus according to the present invention includes the target speed calculation unit 6c that discontinuously changes the target speed Vref as described above. The overall configuration of the printer control apparatus according to the present invention is the same as that of the motor control apparatus shown in FIG.
[0108]
The printer control apparatus according to the present invention can be configured by, for example, the CPU 16 in FIG. In this case, the program for operating the CPU 16 can be recorded and held in, for example, the PROM 21 and the EEPROM 23 in FIG. 4 in addition to the recording medium described below.
[0109]
In the above description, the timing at which the target speed Vref is discontinuously changed is described as the start of deceleration under PID control, but specifically, it may be simultaneously with the start of deceleration. And it may be a predetermined timing after the start of deceleration or any timing after the start of deceleration. In short, it is sufficient if the current speed Vcur does not cause an undershoot with respect to the target speed Vref when the current speed Vcur temporarily decreases rapidly due to the contact of the printing paper.
[0110]
As feedback control, P control and PI control can be adopted in addition to PID control.
[0111]
FIG. 2 is an explanatory diagram showing an external configuration of a recording medium on which a computer program for executing the printer control method according to the present invention is recorded and a computer system in which the recording medium is used, and FIG. 3 is shown in FIG. It is a block diagram which shows the structure of a computer system.
[0112]
A computer system 70 shown in FIG. 2 includes a computer main body 71 housed in a mini tower type housing, a display device 72 such as a CRT (Cathode Ray Tube), a plasma display, and a liquid crystal display device, and a recording device. It comprises a printer 73 as an output device, a keyboard 74a and a mouse 74b as input devices, a flexible disk drive device 76, and a CD-ROM drive device 77. FIG. 3 is a block diagram showing the configuration of the computer system 70. In a housing in which the computer main body 71 is housed, an internal memory 75 such as a RAM (Random Access Memory), a hard disk drive unit 78, and the like. An external memory is further provided. A recording medium on which a computer program for executing the printer control method according to the present invention is recorded is used in the computer system 70. As the recording medium, for example, a flexible disk 81 and a CD-ROM (Read Only Memory) 82 are used. In addition, an MO (Magneto Optical) disk, a DVD (Digital Versatile Disk), other optical recording disks, and a card memory. Alternatively, a magnetic tape or the like may be used.
[0113]
【The invention's effect】
According to the printer control method and the printer control apparatus of the present invention, after the paper feed roller starts the paper feed operation, the upper end of the print paper is moved after the upper end of the print paper hits the paper feed roller and the driven roller. In the speed control of the paper feed motor until the paper feed roller and the driven roller are nipped and stopped, the current speed of the paper feed motor due to the abutting of the upper end of the printing paper to the paper feed roller and the driven roller is determined. The target speed of the paper feed motor is changed discontinuously to such an extent that the undershoot of the current speed with respect to the target speed of the paper feed motor is avoided during the rapid decrease. To prevent undershoot from occurring at the target speed of the current speed due to the upper edge of the printing paper hitting the paper feed roller and driven roller. Rukoto can, can command value to command the acceleration in the deceleration process is prevented from being output. As a result, subsequent overshoots and undershoots can be prevented from occurring in a chain, so that there is no significant disturbance in the current speed and control signal waveforms, and before the printing paper reaches the target stop position. It is possible to completely avoid the situation of stopping on the way.
[0114]
According to the recording medium for a computer program according to the present invention, a computer program for executing any one of the printer control methods according to the present invention in a computer system is recorded. Therefore, any one of the printer control methods according to the present invention described above. By executing the above in a computer system, the same effect as described above can be obtained.
[Brief description of the drawings]
FIG. 1 is a graph showing a target speed and an actual motor speed of a paper feed motor controlled by a printer control method and a printer control apparatus according to the present invention, and waveforms of control signals.
FIG. 2 is an explanatory diagram showing an external configuration of a recording medium on which a program for executing a printer control method according to the present invention is recorded and a computer system using the recording medium.
FIG. 3 is a block diagram showing a configuration of the computer system shown in FIG. 2;
FIG. 4 is a block diagram illustrating a schematic configuration of an inkjet printer.
FIG. 5 is a perspective view showing a configuration around a carriage 3 of an inkjet printer.
6 is an explanatory diagram schematically showing the configuration of a linear encoder 11 attached to a carriage 3. FIG.
FIG. 7 is a timing chart showing waveforms of two output signals of the encoder 11 during normal rotation and reverse rotation of the CR motor.
FIG. 8 is a perspective view showing portions related to paper feed and paper detection.
FIG. 9 is a perspective view showing in detail a portion related to paper feeding of the printer.
FIG. 10 is a block diagram showing a configuration of a DC unit 6 which is a DC motor control device.
11 is a graph showing a motor current and a motor speed of the DC motor motor 4 controlled by the DC unit 6. FIG.
FIG. 12 is an explanatory diagram schematically showing a configuration of a portion related to feeding of printing paper and detection of upper and lower ends of the printing paper in the printer.
FIG. 13 is an explanatory diagram schematically showing a state viewed from the side of a paper feed roller, a paper feed roller, and a print paper when the print paper is skewed.
FIG. 14 is an explanatory diagram schematically showing a state viewed from the upper surface side of a paper feed roller, a paper feed roller, and a print paper when the print paper is skewed.
FIG. 15 shows a first example of the target speed of the paper feed motor, the current speed, and the waveform of the control signal from when the paper feed roller starts the paper feed operation to when it stops for skew removal of the printing paper. Graph.
FIG. 16 is a graph in which only the horizontal axis is enlarged in the section from the remaining distance 300 to 0 to the target stop position in the graph of FIG.
FIG. 17 shows a second example of the target speed of the paper feed motor, the current speed, and the waveform of the control signal from when the paper feed roller starts the paper feed operation to when it stops for deskewing printing paper. Graph.
FIG. 18 is a graph in which only the horizontal axis shows the section from the remaining distance 300 to 0 to the target stop position in the graph of FIG.
[Explanation of symbols]
1 Paper feed motor (PF motor)
2 Paper feed driver
3 Carriage
4 Carriage motor (CR motor)
5 Carriage motor driver (CR motor driver)
6 DC unit
6a Position calculator
6b subtractor
6c Target speed calculation means
6d Speed calculator
6e Subtractor
6f proportional element
6g integral element
6h Differential element
6j D / A converter
7 Pump motor
8 Pump motor driver
9 Recording head
10 Head driver
11 Linear encoder
12 Code plate
13 Encoder (Rotary encoder)
14 Code board for rotary encoder
15 Paper detection sensor
16 CPU
17 Timer IC
18 Host computer
19 Interface section
20 ASIC
21 PROM
22 RAM
23 EEPROM
25 platen
30 pulley
31 Timing belt
32 Guide member for carriage motor
34 Ink cartridge
35 Capping device
36 Pump unit
37 cap
50 chart paper
60 Printer
61 Paper feed slot
62 Outlet
64 Paper feed roller
65 Paper feed roller
66 Followed Roller
67a Large gear
67b Intermediate gear
67c Paper discharge gear
68 Paper discharge roller
69 Followed Roller (Giza Roller)
83 Smap axis
84 Platen
87 Small gear
88 small gear
89 Holder
90 trays

Claims (3)

  After the paper feed roller starts the paper feed operation, after the upper end of the print paper hits the paper feed roller and its driven roller, it stops in a state where the upper end of the print paper is sandwiched between the paper feed roller and its driven roller. In the speed control of the paper feed motor up to the target speed of the paper feed motor when the current speed of the paper feed motor rapidly decreases due to the contact of the upper end of the printing paper with the paper feed roller and the driven roller. The printer control method, wherein the target speed is changed discontinuously to such an extent that an undershoot of the current speed is avoided.   A computer program recording medium on which a computer program for executing the printer control method according to claim 1 in a computer system is recorded.   After the paper feed roller starts the paper feed operation, after the upper end of the print paper hits the paper feed roller and its driven roller, it stops in a state where the upper end of the print paper is sandwiched between the paper feed roller and its driven roller. In the speed control of the paper feed motor up to the target speed of the paper feed motor when the current speed of the paper feed motor rapidly decreases due to the contact of the upper end of the printing paper with the paper feed roller and the driven roller. A printer control apparatus comprising: a target speed calculation unit that discontinuously changes the target speed to such an extent that occurrence of an undershoot of the current speed is avoided.

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