JP3818496B2 - Printer control apparatus and printer control method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a printer control apparatus and a printer control method, and more particularly to cogging of a carriage motor that drives a carriage on which a print head is mounted and between a carriage motor and a carriage for transmitting a driving torque of the carriage motor to the carriage. The present invention relates to a printer control apparatus and a printer control method having a configuration capable of eliminating printing unevenness caused by the influence of periodic fluctuations in the carriage motor speed caused by meshing of gears and timing belts intervening in the belt. 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]
Inkjet printers perform printing by reciprocating a carriage in a horizontal direction orthogonal to the paper feed direction of printing paper, ejecting ink droplets from nozzles of a print head mounted on the carriage, and dropping them on the surface of the printing paper. Is.
[0003]
The reciprocating drive of the carriage in the horizontal direction is performed by a carriage motor via a gear and a timing belt.
[0004]
[Problems to be solved by the invention]
However, in the motor, even during constant speed driving, cogging in which the driving speed fluctuates periodically due to the periodic fluctuation of the driving torque occurs. Further, when a gear and a timing belt are interposed between the motor and the object to be driven, it is considered that the meshing of the gear and the timing belt also contributes to periodic fluctuations in the motor speed.
[0005]
In an inkjet printer, printing is performed during a section in which the carriage is driven at a constant speed, but gears and a timing belt are interposed between the carriage motor and the carriage, and cogging occurs in the carriage motor. In addition, there is a problem that uneven printing occurs due to periodic fluctuations in the motor speed. Hereinafter, this problem will be described in detail with reference to the drawings.
[0006]
FIG. 12 is an explanatory diagram schematically showing how the ink dropping position shifts due to fluctuations in the carriage motor speed. Here, it is assumed that the target speed when the carriage motor is driven at a constant speed is VF, and the motor speed varies from VF− to VF + due to cogging or the like. However, VF− <VF <VF +. Further, the ink discharge speed from the nozzle N of the print head 9 is VS.
[0007]
First, consider a case where ink droplets are ejected from the nozzle N during constant speed driving at the carriage speed VF. In this case, the inertia force in the driving direction acts on the ink droplets ejected from the nozzle N in the vertical direction at the ink ejection velocity VS, and the ink droplets also have a horizontal velocity component VF. Accordingly, the speed of the ink droplet is the combined speed VCF (= (VS) of the ink ejection speed VS of the vertical component and the driving direction speed VF of the horizontal component. ² + VF ² ) ^1/2 ) The direction of the synthesis speed VCF is as shown in FIG. Accordingly, the ink droplets ejected from the nozzle N are dropped at the target dropping position PT on the printing paper 50 which is on the extension in the direction of the synthesis speed VCF.
[0008]
On the other hand, assuming that the ink droplets are ejected from the nozzle N in the vertical direction at the ink ejection speed VS at the moment when the carriage driving speed decreases to VF−, the ink droplet speed is equal to the vertical component ink ejection speed VS and the horizontal direction. Combined speed VCF-(= (VS ² + (VF-) ² ) ^1/2 ) The direction of the synthesis speed VCF− is as shown in FIG. Accordingly, the ink droplets ejected from the nozzle N are dropped at the dropping position PT− on the printing paper 50 on the extension in the direction of the composite speed VCF−. In other words, the ink droplets are dropped from the target drop position PT by a distance L1 than when the driving speed is VF.
[0009]
On the other hand, assuming that the ink droplets are ejected from the nozzle N in the vertical direction at the ink ejection speed VS at the moment when the carriage driving speed increases to VF +, the ink droplet speed is equal to the vertical component ink ejection speed VS and the horizontal component. Speed VVF + (= (VS ² + (VF +) ² ) ^1/2 ) The direction of the synthesis speed VCF + is as shown in FIG. Accordingly, the ink droplets ejected from the nozzle N are dropped at the dropping position PT + on the printing paper 50 on the extension in the direction of the composite speed VCF +. That is, ink droplets are dropped from the target drop position PT in the drive direction by a distance L2 than when the drive speed is VF.
[0010]
As described above, when the carriage driving speed, that is, the carriage motor speed fluctuates from VF− to VF + around the target speed VF, the ink droplet dropping position also shifts.
[0011]
Such a variation in the carriage motor speed is periodic, and is repeated in the same manner for each line printed for each line, resulting in uneven printing. The occurrence of printing unevenness will be described in more detail.
[0012]
FIG. 13 is an explanatory diagram schematically showing the ink drop interval when there is no motor speed fluctuation during constant speed driving and when FIG. 14 shows the motor speed fluctuation during constant speed driving. It is a graph.
[0013]
As shown in FIG. 13A, when constant speed driving is ideally executed, that is, when there is no motor speed fluctuation during constant speed driving, the ink droplet dropping positions are always at regular intervals.
[0014]
On the other hand, when there is a motor speed fluctuation during constant speed driving due to cogging of the carriage motor, etc., there is a deviation caused by the ink droplet dropping timing, and the ink droplet dropping position is not always at a constant interval.
[0015]
Even if the target speed during constant speed driving is VF, the actual driving speed periodically varies from VF− to VF + around the target speed VF, as shown in FIG. Here, it is assumed that VF− <VF <VF +.
[0016]
As described above with reference to FIG. 12, since the drop position of the ink droplet is shifted according to the fluctuation of the driving speed, the print head is printed at the time tx when the actual driving speed becomes the speed VF− lower than the target speed VF. The ink droplets ejected from this nozzle are dropped by a distance L1 from the original target dropping position, for example, as the ink dot D1 in FIG. 13B. Further, the ink droplets ejected from the nozzles of the print head at the time ty when the actual driving speed becomes the speed VF + higher than the target speed VF are, for example, the original target as in the ink dot D2 in FIG. The droplet is dropped from the dropping position by a distance L2 in the driving direction.
[0017]
In an ink jet printer, ink droplets are dropped for each line, and printing is performed so that each line is completely filled with ink dots, but printing is performed in a section where the carriage motor is driven at a constant speed. .
[0018]
In the conventional printer control apparatus and printer control method, the motor speed during constant speed driving in each line is set to be constant, and the section in which the carriage motor is driven at constant speed is constant. Carriage driving at a driving speed with periodic fluctuation as shown in FIG.
[0019]
As a result, the ink dots become dense in almost the same part of each line, and the ink dots become sparse in almost the same part of each line. A phenomenon occurs in which the printed color becomes lighter in a portion where dots are sparse.
[0020]
Therefore, when the entire printed image is viewed, printing unevenness occurs in which a color of a certain part is printed darkly and a color of a certain part is printed lightly. Such uneven printing becomes more conspicuous as the size of the ejected ink droplets becomes smaller as the quality of printing by an ink jet printer increases.
[0021]
The present invention has been made in view of the above-described problems, and an object of the present invention is to provide a printer having a configuration capable of eliminating printing unevenness that occurs due to the influence of periodic fluctuations in carriage motor speed caused by cogging of the carriage motor. A control device and a printer control method are provided.
[0022]
[Means for Solving the Problems]
According to the printer control device and the printer control method according to the present invention, the drive speed in the drive section for executing printing of the carriage motor that drives the carriage on which the print head that performs printing by ejecting ink droplets is mounted is set as described above. The value is changed so as to be different for each main scanning operation in the main scanning direction which is the driving direction of the carriage.
[0023]
Alternatively, according to the printer control device and the printer control method according to the present invention, the drive current in the drive section for printing execution of the carriage motor that drives the carriage on which the print head that performs printing by ejecting ink droplets is mounted is obtained. The main scanning operation in the main scanning direction, which is the driving direction of the carriage, is changed so as to have a different value.
[0024]
Alternatively, according to the printer control device and the printer control method according to the present invention, the drive voltage duty in the drive section for the printing execution of the carriage motor that drives the carriage on which the print head that performs printing by discharging ink droplets is mounted. The ratio is changed so as to have a different value for each main scanning operation in the main scanning direction which is the driving direction of the carriage.
[0025]
In other words, according to the printer control device and the printer control method of the present invention, the drive section for executing printing of the carriage motor that drives the carriage on which the print head that performs printing by discharging ink droplets for each line is mounted. The driving speed is changed for each line so as to have different values for the preceding and succeeding lines adjacent to each other.
[0026]
Alternatively, according to the printer control device and the printer control method of the present invention, in the drive section for printing execution of the carriage motor that drives the carriage on which the print head that performs printing by discharging ink droplets for each line is mounted. The drive current is changed for each line so as to have different values for the preceding line and the succeeding line adjacent to each other.
[0027]
Alternatively, according to the printer control device and the printer control method of the present invention, in the drive section for printing execution of the carriage motor that drives the carriage on which the print head that performs printing by discharging ink droplets for each line is mounted. The drive voltage duty ratio is changed for each line so as to have different values for the preceding line and the succeeding line adjacent to each other.
[0028]
With the above configuration, even if the ink droplet dropping position is shifted due to the periodic fluctuation of the driving speed due to cogging of the carriage motor, the ink droplet dropping position is shifted between the preceding line and the succeeding line adjacent to each other. The degree of is different. As a result, the ink dots do not become dense in almost the same part of each line, and the ink dots do not become sparse in almost the same part of each line. It is possible to eliminate printing unevenness in which the color of a part is printed dark and the color of a part is printed light.
[0029]
The driving section for executing the printing may be a constant speed driving section. Alternatively, the drive section for executing the printing may be an acceleration / deceleration drive section. Alternatively, the driving section for executing the printing may be a constant speed driving section and an acceleration / deceleration driving section.
[0030]
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.
[0031]
DETAILED DESCRIPTION OF THE INVENTION
First, a schematic configuration and control method of an ink jet printer to which a printer control device and a printer control method according to the present invention are applied will be described.
[0032]
FIG. 4 is a block diagram showing a schematic configuration of the ink jet printer.
[0033]
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 and the drive waveform of the head 9 based on the print information sent from the host computer 18 via 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.
[0034]
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.
[0035]
FIG. 5 is a perspective view showing a configuration around the carriage 3 of the ink jet printer.
[0036]
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.
[0037]
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.
[0038]
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.
[0039]
FIG. 6 is an explanatory diagram schematically showing the configuration of the linear encoder 11 attached to the carriage 3.
[0040]
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.
[0041]
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)).
[0042]
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.
[0043]
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.
[0044]
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.
[0045]
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.
[0046]
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.
[0047]
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.
[0048]
FIG. 9 is a perspective view showing in detail a portion related to paper feeding of the printer.
[0049]
A portion related to paper feeding in the printer portion shown in FIG. 8 will be described in more detail with reference to FIGS.
[0050]
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.
[0051]
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.
[0052]
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.
[0053]
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.
[0054]
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.
[0055]
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.
[0056]
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.
[0057]
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 forward, and is "-1" when one edge is detected when the CR motor 4 is rotating in reverse. 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.
[0058]
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.
[0059]
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).
[0060]
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.
[0061]
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.
[0062]
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.
[0063]
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.
[0064]
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.
[0065]
The timer 6k generates a timer interrupt signal every predetermined time based on the clock signal sent from the CPU 16.
[0066]
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.
[0067]
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.
[0068]
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).
[0069]
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.
[0070]
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).
[0071]
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.
[0072]
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.
[0073]
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.
[0074]
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.
[0075]
DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, embodiments of a printer control device and a printer control method according to the invention will be described with reference to the drawings.
[0076]
FIG. 1 is a graph showing motor current and motor speed of a carriage motor controlled by the printer control apparatus and printer control method according to the present invention.
[0077]
The printer control device and the printer control method according to the present invention provide a driving speed in a driving section for printing execution of a carriage motor that drives a carriage on which a print head that performs printing by discharging ink droplets is mounted. This is characterized in that the value is changed so as to be different for each main scanning operation in the main scanning direction.
[0078]
In other words, the printer control device and the printer control method according to the present invention drive in a drive section for printing execution of a carriage motor that drives a carriage on which a print head that performs printing by discharging ink droplets for each line is mounted. It is characterized in that the speed is changed for each line so that the speed is different between the preceding line and the succeeding line adjacent to each other.
[0079]
The motor speed of the carriage motor controlled by the printer control device and the printer control method according to the present invention is shown in the graph of FIG. As is apparent from the motor speed waveform, constant speed driving is performed in the time interval from time ta to time tb, and printing is performed during this time.
[0080]
As shown in this example, in the printer control device and the printer control method according to the present invention, as the driving speed when the carriage motor is driven at a constant speed, a value several percent lower than the standard driving speed VF in addition to the standard driving speed VF. The slightly decreasing adjustment driving speed VFx and the slightly increasing adjusting driving speed VFy, which is a value several percent higher than the standard driving speed VF, can be set.
[0081]
Then, the driving speed at the time of constant speed driving for printing of the carriage motor is changed for each line so as to have different values in the preceding line and the succeeding line adjacent to each other. For example, the driving speed in the constant speed driving is sequentially changed so that the driving speeds in the constant speed driving for executing printing of three consecutive lines become VFx, VF, and VFy, respectively. Further, for the subsequent lines, VFx, VF, VFy, VFx, VF, VFy,. . . And the driving speed at the time of constant speed driving is changed.
[0082]
If the driving speed in the constant speed driving has different values in the preceding line and the succeeding line adjacent to each other, the change order is arbitrary. Also, the repeating pattern need not be constant.
[0083]
As described above, in the printer control device and the printer control method according to the present invention, the driving speeds at the constant speed driving for the printing execution of the carriage motor are different between the preceding line and the succeeding line adjacent to each other. Since the value is changed for each line so that the value becomes a value, even if the drop position of the ink droplet is shifted due to the periodic fluctuation of the driving speed caused by cogging of the carriage motor, the preceding line and the succeeding line adjacent to each other The degree of deviation of the ink droplet dropping position is different.
[0084]
As a result, the ink dots do not become dense in almost the same part of each line, and the ink dots do not become sparse in almost the same part of each line. The printing unevenness in which the color of a part is printed dark and the color of a part is printed lightly is eliminated.
[0085]
Therefore, according to the printer control device and the printer control method of the present invention, it is possible to eliminate printing unevenness due to periodic fluctuations in the driving speed caused by cogging of the carriage motor.
[0086]
The slight decrease adjustment drive speed VFx and the slight increase adjustment drive speed VFy are values that are several percent lower than the standard drive speed VF and several percent higher than the standard drive speed VF, respectively, but in reality, various conditions such as the print mode are considered. And set the value.
[0087]
In short, the degree of deviation of the ink droplet dropping position between the preceding line and the succeeding line that are adjacent to each other when a deviation occurs in the ink droplet dropping position due to periodic fluctuations in the driving speed caused by cogging of the carriage motor, etc. It is good to set to the extent that becomes different. However, assuming that the ejection timing of the ink droplet in relation to the target droplet position of the ink droplet is constant, the difference between the standard driving speed VF and the slight decrease adjustment driving speed VFx, the standard driving speed VF and the slight increase adjustment driving speed. If the difference from VFy is too large, the drop positions of the ink droplets in the preceding line and the succeeding line that are adjacent to each other will be greatly shifted, leading to a decrease in print quality. Set to an appropriate value.
[0088]
In the present embodiment, the driving speed at the time of constant speed driving for printing execution of the carriage motor is changed to three stages. However, the driving speed is changed to an arbitrary stage of two or more stages. Good.
[0089]
The printer control device and the printer control method according to the present invention have been described from the viewpoint of drive speed control. However, since the drive speed of the motor is controlled by the drive current, the description will be made from the viewpoint of drive current control. You can also.
[0090]
That is, the printer control apparatus and the printer control method according to the present invention provide a driving current in a driving section for printing execution of a carriage motor that drives a carriage on which a print head that performs printing by ejecting ink droplets is mounted. It can also be said that the characteristic is that the value is changed so as to be different for each main scanning operation in the main scanning direction, which is the driving direction.
[0091]
In other words, the printer control device and the printer control method according to the present invention are driven at a constant speed for printing by a carriage motor that drives a carriage on which a print head that performs printing by ejecting ink droplets for each line is mounted. This is characterized in that the drive current at this time is changed for each line so that the driving current is different between the preceding line and the succeeding line.
[0092]
The motor current of the carriage motor controlled by the printer control device and the printer control method according to the present invention is shown in the graph of FIG. As described above, in this example, constant speed driving is performed in the time interval from time ta to time tb, and printing is performed during this time.
[0093]
As shown in this example, in the printer control apparatus and the printer control method according to the present invention, the driving current for driving the carriage motor at a constant speed is a value that is several percent lower than the standard driving current IF in addition to the standard driving current IF. It is possible to set a slightly decreasing adjustment driving current IFx and a slightly increasing adjustment driving current IFy which is a value several percent higher than the standard driving current IF.
[0094]
Then, the driving current at the time of constant speed driving for printing of the carriage motor is changed for each line so that the driving current is different between the preceding line and the succeeding line. For example, the drive current in the constant speed drive is sequentially changed so that the drive current in the constant speed drive for executing printing of three consecutive lines becomes IFx, IF, and IFy, respectively. In the same manner, the subsequent lines are also IFx, IF, IFy, IFx, IF, IFy,. . . And the drive current at the time of constant speed drive is changed.
[0095]
If the driving current in the constant speed driving has different values between the preceding line and the succeeding line adjacent to each other, the order of change is arbitrary. Also, the repeating pattern need not be constant.
[0096]
As described above, in the printer control device and the printer control method according to the present invention, the drive currents at the constant speed drive for printing execution of the carriage motor are different between the preceding line and the succeeding line adjacent to each other. Since the value is changed for each line so as to become a value, it is possible to eliminate printing unevenness due to periodic fluctuations in the driving speed caused by cogging of the carriage motor, etc., as described above from the viewpoint of speed control.
[0097]
The slight decrease adjustment drive current IFx and the slight increase adjustment drive current IFy are values that are several percent lower than the standard drive current IF and several percent higher than the standard drive current IF, respectively, but in reality, various conditions such as the print mode are considered. And set the value.
[0098]
In short, the degree of deviation of the ink droplet dropping position between the preceding line and the succeeding line that are adjacent to each other when a deviation occurs in the ink droplet dropping position due to periodic fluctuations in the driving speed caused by cogging of the carriage motor, etc. It is good to set to the extent that becomes different. However, assuming that the ejection timing of the ink droplet in relation to the target droplet position of the ink droplet is constant, the difference between the standard drive current IF and the slight decrease adjustment drive current IFx, the standard drive current IF and the slight increase adjustment drive current If the difference from IFy is too large, the drop positions of the ink droplets in the preceding and succeeding lines that are adjacent to each other will be greatly shifted, leading to a decrease in print quality. Set to an appropriate value.
[0099]
In this embodiment, the driving current at the time of constant speed driving for printing of the carriage motor is changed to three stages. However, the driving current is changed to an arbitrary stage of two or more stages. Good.
[0100]
In the present embodiment, the drive current is changed in order to control the drive speed at the time of constant speed drive for print execution of the carriage motor. However, instead of the drive current, pulse width modulation (PWM : Pulse Width Modulation) control may change the drive voltage output duty ratio.
[0101]
Furthermore, in the present embodiment, the drive section for printing execution of the carriage motor is a constant speed drive section. However, when printing is performed also in the acceleration / deceleration drive section, the drive speed in the acceleration / deceleration drive section is also set. The preceding line and the succeeding line adjacent to each other may be changed for each line so as to have different values.
[0102]
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.
[0103]
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.
[0104]
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, a liquid crystal display device, and the like. 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 are shown. 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.
[0105]
【The invention's effect】
According to the printer control apparatus and the printer control method of the present invention, the drive speed or drive current in the drive section for printing execution of the carriage motor that drives the carriage on which the print head that performs printing by discharging ink droplets is mounted. Alternatively, since the drive voltage duty ratio is changed to have a different value for each main scanning operation in the main scanning direction which is the driving direction of the carriage, in other words, printing is performed by ejecting ink droplets for each line. The drive speed or drive current or drive voltage duty ratio in the drive section for printing execution of the carriage motor that drives the carriage on which the print head is mounted is set to a different value between the preceding line and the subsequent line. Because it is changed for each line so that it becomes That even shifted to the dropping position of the ink droplets is generated by a periodic variation of the driving speed, the degree of deviation of the dropping position of the ink droplets in the preceding lines adjacent to each other and subsequent lines are different. As a result, the ink dots do not become dense in almost the same part of each line, and the ink dots do not become sparse in almost the same part of each line. It is possible to eliminate printing unevenness in which the color of a part is printed dark and the color of a part is printed light.
[0106]
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 motor current and motor speed of a carriage motor controlled by a printer control device and a printer control method according to the present invention.
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 how ink drop positions shift due to a change in carriage motor speed.
FIG. 13 is an explanatory view schematically showing ink drop intervals when there is no motor speed variation and when there is no motor speed variation.
FIG. 14 is a graph showing fluctuations in motor speed during constant speed driving.
[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

Claims (19)

For each main scanning operation in the main scanning direction, which is the driving direction of the carriage, the driving speed in the driving section for printing execution of the carriage motor that drives the carriage on which the print head that performs printing by discharging ink droplets is mounted. A printer control device, wherein the printer control device is changed to have different values. The driving current in the driving section for printing execution of the carriage motor that drives the carriage on which the print head that performs printing by discharging ink droplets is mounted is set for each main scanning operation in the main scanning direction that is the driving direction of the carriage. A printer control device, wherein the printer control device is changed to have different values. The main scanning operation in the main scanning direction that is the driving direction of the carriage is the driving voltage duty ratio in the driving section for printing execution of the carriage motor that drives the carriage on which the print head that performs printing by ejecting ink droplets is mounted. A printer control device, wherein the printer control device is changed so as to have different values. The driving speed in the driving section for printing execution of the carriage motor that drives the carriage on which the print head that performs printing by discharging ink droplets for each line is different between the preceding line and the following line. A printer control apparatus characterized by changing for each line so as to be a value. The driving current in the driving section for printing execution of the carriage motor that drives the carriage on which the print head that performs printing by ejecting ink droplets for each line is different in the preceding line and the following line adjacent to each other. A printer control apparatus characterized by changing for each line so as to be a value. The drive voltage duty ratio in the drive section for printing execution of the carriage motor that drives the carriage on which the print head that performs printing by discharging ink droplets for each line is set in the preceding line and the succeeding line adjacent to each other. A printer control apparatus, wherein the printer control apparatus is changed for each line so as to have different values. The printer control apparatus according to claim 1, wherein the driving section for executing printing is a constant speed driving section. The printer control apparatus according to claim 1, wherein the drive section for executing printing is an acceleration / deceleration drive section. The printer control apparatus according to claim 1, wherein the drive sections for execution of printing are a constant speed drive section and an acceleration / deceleration drive section. For each main scanning operation in the main scanning direction, which is the driving direction of the carriage, the driving speed in the driving section for printing execution of the carriage motor that drives the carriage on which the print head that performs printing by discharging ink droplets is mounted. A printer control method, characterized in that the value is changed to have a different value. The driving current in the driving section for printing execution of the carriage motor that drives the carriage on which the print head that performs printing by discharging ink droplets is mounted is set for each main scanning operation in the main scanning direction that is the driving direction of the carriage. A printer control method, characterized in that the value is changed to have a different value. The main scanning operation in the main scanning direction that is the driving direction of the carriage is the driving voltage duty ratio in the driving section for printing execution of the carriage motor that drives the carriage on which the print head that performs printing by ejecting ink droplets is mounted. A printer control method characterized by changing the value so as to be different for each. The driving speed in the driving section for printing execution of the carriage motor that drives the carriage on which the print head that performs printing by discharging ink droplets for each line is different between the preceding line and the following line. A printer control method characterized by changing for each line so as to become a value. The driving current in the driving section for printing execution of the carriage motor that drives the carriage on which the print head that performs printing by ejecting ink droplets for each line is different in the preceding line and the following line adjacent to each other. A printer control method characterized by changing for each line so as to become a value. The drive voltage duty ratio in the drive section for printing execution of the carriage motor that drives the carriage on which the print head that performs printing by discharging ink droplets for each line is set in the preceding line and the succeeding line adjacent to each other. A printer control method, characterized by changing for each line so as to have different values. 16. The printer control method according to claim 10, wherein the drive section for executing printing is a constant speed drive section. The printer control method according to claim 10, wherein the drive section for executing printing is an acceleration / deceleration drive section. 16. The printer control method according to claim 10, wherein the drive sections for executing printing are a constant speed drive section and an acceleration / deceleration drive section. 19. A computer program recording medium having recorded thereon a computer program for executing the printer control method according to claim 10 in a computer system.

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