JPH0920030A - Serial printer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce electric power consumption by a carrier motor and thereby, lower the amount of heat by printing data based on a combination of constant speed control time and shorter acceleration/deceleration control time of a carrier of the standard combinations of constant speed control time and acceleration/ deceleration control time of the carrier. SOLUTION: A CPU 1 receives a single line of print data from a host computer 15, then controls the drive of a carrier motor 9 at a constant speed only for a constant speed control time 12 after controlling the acceleration of the motor 9 for an acceleration control time (t1), and prints out the data with a printing head 7. Next, the CPU 1 decelerates the carrier motor 9 under control for a deceleration time (t1) and stops the motor to allow the printing head 7 to print a single line. In this case, the CPU 1 calculates a solution for printing the single line using its required time T in the shorter acceleration control time (t1) mode, and prints the single line based on the solution. Thus the printing is performed by calculating optimal conditions for the drive of the motor by saving power consumption at the same throughput when data is printed by moving the carrier in accordance with the length of the print data.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a serial printer for printing while moving a carrier having a print head.

[0002]

2. Description of the Related Art This type of serial printer has a print head, which faces a platen, mounted on a carrier, and has a carrier motor for driving the carrier. The carrier motor is accelerated and decelerated to control the main scanning direction along the platen. The print output is performed line by line while moving the carrier.

Specifically, when printing one line, first, the carrier motor is controlled to accelerate the carrier to a predetermined constant speed by the print start position. When the carrier motor reaches a constant speed, print output from the print head is performed. After that, when the printing output is completed, the carrier motor is controlled to decelerate the carrier and stop the carrier at a predetermined position. By repeating such a printing operation for each line, the printing of one page is completed.

In such a serial printer,
Conventionally, the printing speed has always been constant regardless of the data length of one line to be printed. Therefore, when the data length for one line is short, most of the carrier movement operation is assigned to the acceleration operation up to a constant speed and the deceleration stop operation from the constant speed when printing is performed.

[0005]

By the way, the power consumption required for the acceleration and deceleration stop operations in the carrier motor is much larger than the power consumption required for maintaining a constant speed. Therefore, in the serial printer as described above, the shorter the data length for one line is, the longer the time spent for the acceleration operation and the deceleration operation of the carrier is, and the power consumption required for this is increased.
Therefore, there is a problem that the amount of heat generated by the carrier motor increases.

Further, the faster the constant speed of the carrier motor when printing is performed, the more time it takes to accelerate and decelerate the carrier, and the power consumption increases accordingly. For this reason, there is also a problem in that the amount of heat generated by the carrier motor increases as the constant speed for printing output is set to be high in order to realize high-speed printing.

Therefore, the present invention is intended to provide a serial printer which can reduce the power consumption to the carrier motor and thereby reduce the heat generation amount of the carrier motor.

[0008]

According to a first aspect of the present invention, there is provided carrier driving means for running and scanning a carrier on which a print head is mounted in the main scanning direction, and the carrier driving means is controlled to set a predetermined carrier. It accelerates to a constant speed, and at this constant speed, print output from the print head is performed.
In a serial printer that prints on a line-by-line basis by decelerating and stopping the carrier when printing is completed, the carrier is driven at a constant speed based on the relational expression of speed and acceleration according to the data length of one line. Control time calculation means for calculating a combination of these control times when the total time of constant speed control time for control and acceleration / deceleration control time for acceleration control and deceleration control of the carrier is constant, and this control time calculation means Among the combinations of the calculated control times, the print control means for performing the line printing based on the combination of the control times having a shorter acceleration / deceleration control time is provided.

According to a second aspect of the present invention, there is provided carrier driving means for running and scanning a carrier having a print head in the main scanning direction. The carrier driving means is controlled to accelerate the carrier to a predetermined constant speed, In a serial printer that prints from the print head at this constant speed, and when printing is completed, the carrier is decelerated and stopped to print one line at a time, depending on the data length for one line. Based on the relational expression of the acceleration and the acceleration, the control time calculating means for calculating the combination of these control times that minimizes the total time of the constant speed control time and the acceleration / deceleration control time, and the control calculated by this control time calculating means. A printing control means for performing line printing based on a combination of time is provided.

[0010]

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

FIG. 1 is a block diagram showing the configuration of the present embodiment. 1 is a CPU (central processing unit) that constitutes the main body of the control unit, and 2 is the program data for the CPU 1 to control each unit. ROM (read only memory) 3, RAM (random access memory) provided with a memory used for data processing, a print buffer for storing data from the host computer 15 for each line, 4 is I / O (input / output) port, 5 is I
/ F (interface). CPU1 and ROM
2, a RAM 3, an I / O port 4, and an I / F 5 are electrically connected by a bus line 6.

The I / O port 4 drives a head driver 8 for driving the print head 7, and a carrier motor 9 for controlling movement of a carrier carrying the print head 7 along a platen provided inside the printer. A motor driver 10 and a motor driver 12 that drives a paper feed motor 11 that drives the platen and the like are connected to each other. A host computer 15 is connected to the I / F 5 via a communication line.

When printing one line, the CPU 1 first controls the carrier motor 9 to accelerate, and when it reaches a certain speed, causes the print head 7 to perform print output, and then controls the carrier motor 9 to decelerate. Stop the carrier.

When the CPU 1 performs such a printing process, the acceleration / deceleration control time of the carrier motor 9 required to print one line as the optimum power saving drive condition of the same throughput based on the following formula ( The optimum values of the time required for the acceleration control and the deceleration control of the carrier) and the constant speed control time (the time for driving and controlling the carrier at a constant speed to output from the print head 7) are calculated. There is.

That is, the acceleration during the acceleration control and the deceleration control of the carrier motor 9 is a, the printing constant speed required when the print output from the print head 7 is performed is v, and it is necessary to accelerate to this speed v. The acceleration control time or the deceleration control time required for deceleration from the speed v to the stop is t1, and the time for maintaining the constant speed v during printing, that is, the constant speed control time is t2, and the print data for one line is actually When the distance of the print data in the main scanning direction when printing on L is L, the constant speed v during printing and the distance L of the print data are
It can be expressed by the following relational expression of velocity and acceleration. v = a · t1 (1) L = v · t2 (2) Here, since the acceleration control time and the deceleration control time of the carrier motor 9 are equal to t1, the total required to print one line Time, that is, total printing time (total time)
T becomes T = 2t1 + t2 (3)

An optimum value in consideration of power saving of the acceleration control time t1 of the carrier motor 9 and the constant speed control time t2 when the total printing time T for one line is constant (constant throughput) is obtained.

That is, since the constant speed during printing v = a · t1 and the equation (2), L = v · t2 = a · t1 · t2 ∴t2 = L / (a · t1) (4) By substituting this equation (4) into equation (3) and erasing t2, T = 2t1 + L / (at1) (5) This equation (5) defines the acceleration control time t1 of the carrier motor 9. Since it is a quadratic equation when it is used as a variable, there can be two solutions of this acceleration control time t1. That is, there are two combinations of the acceleration control time t1 and the constant speed control time t2 when the printing time for one line is the same (throughput is the same).

Of these combinations, the acceleration control time t1
Is smaller, the power supplied to the carrier motor 9 can be smaller. Therefore, the combination of the acceleration control time t1 with the smaller acceleration control time t1 and the constant speed control time t2 is the optimum combination when power saving is considered with the same total printing time T (same throughput). .

Specifically, for example, a = 1000 Inch / s
² , when L = 1 Inch and V = 50 Inch / s, t1 = 50 ms and t2 = 20 ms from equations (1) and (2), so the total print time T for one line is calculated from equation (3). It looks like this:

T = 2 · 50 + 20 = 120 ms = 0.12 s Therefore, when substituting in the equation (5), 0.12 = 2 · t1 + 1 / (1000 · t1) When this is solved, t1 = 50 ms, 20 ms Then, under the condition that a = 1000 Inch / s ² and L = 1 Inch, the acceleration control time t 1 = 50 ms, 20 ms
FIG. 4 shows a plot of the relationship between the carrier moving distance S and the time t when one line is printed with.

The graph y1 in the figure shows the acceleration control time t1 =
In the case of 50 ms, the graph y2 shows the acceleration control time t1 = 2
This is the case for 0 ms. The graphs y1 and y2 show the print output and the dotted line portion that draws a downwardly convex parabola with the carrier motor 9 accelerating from time 0 to a constant printing speed v (constant) with time. It is composed of a straight line portion having a constant speed v (constant) at the time of printing performed, and a dotted line portion that draws a convex parabola that is decelerated until the carrier motor 9 stops.

The distance in the y-axis direction of the straight line portion of the graphs y1 and y2 is equal to the distance L of the print data,
The speed is different. That is, the graph y2 is the graph y
Slower than 1 However, the time T required to print one line is the same.

Therefore, although the time T required to print one line is the same, the graph y2 in which the constant printing speed v is small consumes less power. Therefore, as the maximum throughput condition with the power saving effect, the combination of the acceleration control time t1 and the constant speed control time t2 in the case of the acceleration control time t1 = 20 ms (graph y2) is the most suitable when considering the power saving. I know there is.

Utilizing the above-mentioned principle, the CPU 1 specifically performs optimization control of a combination of the acceleration control time t1 and the constant speed control time t2 as shown in FIG. That is, the CPU 1 determines in ST (step) 1 whether print data is received from the host computer 15.

At this time, when it is determined that the print data is received from the host computer 15, the optimum power saving drive condition of the same throughput is calculated in ST2 (control time calculation means). That is, the time T required to print one line is obtained from the acceleration control time t1 and the constant speed control time t2 when the data length L of the received print data is printed by driving the carrier motor 9 at high speed.

Then, by substituting the data length L and the acceleration a of the carrier motor 9 into the equation (5), one line can be printed at the same time as this time T, and the solution for which the acceleration control time t1 is short is calculated. To do. Based on this acceleration control time t1,
The constant speed control time t2 is derived from the equation (3). Subsequently, in ST3, the driving condition calculated in ST2, that is, the combination of the acceleration / deceleration control time t1 and the constant speed control time t2,
The printing operation for one line is performed (print control means).

Specifically, the carrier motor 9 is accelerated and controlled at the acceleration control time t1, then the constant speed drive control is performed for the constant speed control time t2, and the print head 7 outputs the print. After that, the carrier motor 9 is decelerated at the deceleration control time t1 and stopped. In this way, one line is printed, and the process returns to ST1.

In this embodiment of the present invention, when the print data for one line is received from the host computer 1, the acceleration control time t1 and the constant speed control time for moving the carrier at high speed for printing The time T required to print one line is obtained based on t2, etc., and the solution with the smaller acceleration control time t1 at the same time as this time T, that is, the one with a slower constant speed when printing is output, The solution is calculated, and printing for one line is performed based on the acceleration control time t1 and the constant speed control time t2.

As described above, the optimum power saving drive condition is calculated for each line with the same throughput as in the case where printing is performed by moving the carrier at high speed in accordance with the data length of the print data for one line. By repeating the printing based on this, the printing of one page is completed.

As a result, the amount of power consumed by the carrier motor 9 can be reduced, and the amount of heat generated by the carrier motor can be reduced. Moreover, it is possible to maintain the same throughput as when printing is performed by moving the carrier at high speed. When the data length of the print data for one line is short, the acceleration / deceleration time t1 can be greatly reduced, which is particularly effective.

In this embodiment, the print data is received line by line from the host computer 1 and the optimum power saving drive condition of the same throughput is calculated line by line, but this is not always the case. The present invention is not limited to this, and the optimum power-saving drive condition of the same throughput may be calculated in advance for each data length of print data, or may be converted into data by actual measurement and stored in the ROM 2.

In this case, the CPU 1 may perform optimization control of a combination of the acceleration control time t1 and the constant speed control time t2 as shown in FIG. That is,
In ST11, it is determined whether print data is received from the host computer 15.

At this time, when it is determined that the print data is received from the host computer 15, the optimum power saving drive condition of the same throughput corresponding to the data length of the print data received in ST12, that is, the acceleration control time t1 and the constant speed is obtained. A combination with the control time t2 is selected from the data table of the ROM2.

Subsequently, in ST13, the printing operation for one line is performed under the driving condition selected in ST12, that is, the combination of the acceleration / deceleration control time t1 and the constant speed control time t2.
The process returns to ST11.

In this way, by storing in advance the optimum power-saving driving condition of the same throughput corresponding to the data length in the data table of the ROM 2, it is not necessary to perform the calculation for each line. Further, the throughput of the entire device can be improved.

Next, another embodiment of the present invention will be described with reference to FIGS. In the present embodiment, the same parts as those in the above embodiment are designated by the same reference numerals and detailed description thereof will be omitted.

The present embodiment is different from the above embodiment in that the acceleration control time t1 and the constant speed control for the slower constant speed when performing print output at the same throughput as when the carrier is driven at a high speed. Instead of setting the time t2 to the optimum value, the acceleration control time t1 and the constant speed control time t2 when the throughput becomes maximum are set to the optimum values.

That is, based on the above equations (3) and (4), the combination of the acceleration control time t1 and the constant speed control time t2 at which the total printing time T for one line is the minimum (the throughput is the maximum) (solution) Is only one).

The same conditions as those described in the above embodiment,
That is, when a = 1000 Inch / s ² and L = 1 Inch, the acceleration control time t1 and the constant speed control time t2 at which the total print time T for one line is minimum (highest throughput) are t1 = 22.36 ms, respectively. t2 = 44.68 ms, and the total printing time Ts at this time is 89.4 ms.
Becomes

Thus, a = 1000 Inch / s ² , L
= 1 Inch, the acceleration control time t1 = 22.
A plot of the relationship between the carrier moving distance S and the time t when one line is printed in 36 ms is plotted as a graph y3 shown in FIG.

Although the inclination of the straight line portion of the graph y3, that is, the constant speed v during printing is larger than the graph y2 shown in FIG. It can be seen that it is smaller than the total printing time T for one line in the case of y1.

Therefore, when printing is performed based on the acceleration control time t1 and the constant speed control time t2 that minimize the total printing time T for one line, when the carrier is moved at high speed to perform printing ( It consumes less power than the graph y1) and improves overall throughput.

Utilizing the above principle, the CPU 1 in the present embodiment is adapted to perform the optimization control of the combination of the acceleration control time t1 and the constant speed control time t2 as shown in FIG. That is, the CPU 1 determines in ST21 whether print data is received from the host computer 15.

At this time, when it is determined that the print data is received from the host computer 15, the maximum throughput drive condition with a power saving effect is calculated in ST22 (control time calculation means). That is, the total print time T for one line when printing the data length L of the received print data
Acceleration control time t1 and constant speed control time t that minimize
The combination of 2 is calculated based on the equations (3) and (4).

Subsequently, in ST23, a printing operation for one line is performed (print control means) under the combination of the driving condition calculated in ST22, that is, the acceleration / deceleration control time t1 and the constant speed control time t2, and the processing of ST21 is performed. Return.

In the embodiment of the present invention having such a configuration, when the print data for one line is received from the host computer 1, the maximum throughput driving condition with the power saving effect is obtained according to the data length L of the received print data. That is, the acceleration control time t1 and the constant speed control time t2 are calculated, and printing for one line is performed based on the acceleration control time t1 and the constant speed control time t2.

As described above, the maximum throughput driving condition with a power saving effect, that is, the total printing time T for one line, is obtained according to the data length of the printing data for one line for each line.
Is calculated for the shortest time, and printing is repeated based on this driving condition to finish printing one page.

As a result, the amount of power consumed by the carrier motor 9 can be reduced, and the amount of heat generated by the carrier motor can be reduced. Moreover, the throughput of the entire device can be improved. When the data length of the print data for one line is short, the acceleration / deceleration time t1 can be greatly reduced, which is particularly effective.

In this embodiment, the print data is received line by line from the host computer 1 and the maximum throughput drive condition with a power saving effect is calculated line by line, but this is not always the case. However, the maximum throughput drive condition with a power saving effect is calculated in advance for each data length of the print data, or is converted into data by actual measurement, and this RO
It may be stored in M2.

In this case, the CPU 1 may perform optimization control of a combination of the acceleration control time t1 and the constant speed control time t2 as shown in FIG. That is,
In ST31, it is determined whether print data is received from the host computer 15.

At this time, when it is determined that the print data is received from the host computer 15, the maximum throughput drive condition with the power saving effect corresponding to the data length of the print data received in ST32, that is, the acceleration control time t1.
And a constant speed control time t2 are selected from the data table of the ROM2.

Subsequently, in ST33, the printing operation for one line is performed under the driving condition selected in ST32, that is, the combination of the acceleration / deceleration control time t1 and the constant speed control time t2.
Returning to the processing of ST31.

In this way, by storing in advance the maximum throughput driving condition having a power saving effect corresponding to the data length in the data table of the ROM 2, it is not necessary to perform the calculation for each line. Further, the throughput of the entire device can be improved.

[0054]

As described in detail above, according to the present invention, it is possible to provide a serial printer which can reduce the power consumption of the carrier motor and thereby reduce the heat generation amount of the carrier motor. Is. Also,
The throughput of the entire device can be improved.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of an embodiment of the present invention.

FIG. 2 is a flowchart showing an optimization control for performing a printing operation under an optimum power saving drive condition of the same throughput in the same embodiment.

FIG. 3 is a flowchart showing an optimization control for performing a printing operation under an optimum power saving drive condition of the same throughput in the same embodiment.

FIG. 4 is a diagram showing a relationship between a moving distance of a carrier and time in the same embodiment.

FIG. 5 is a flowchart showing an optimization control for performing a printing operation under a maximum throughput driving condition with a power saving effect in another embodiment of the present invention.

FIG. 6 is a flow chart showing an optimization control for performing a printing operation under the highest throughput driving condition with a power saving effect in the embodiment.

FIG. 7 is a diagram showing a relationship between a moving distance of a carrier and time in the same embodiment.

[Explanation of symbols]

 1 ... CPU 7 ... Print head 9 ... Carrier motor (carrier driving means)

Claims (2)

[Claims] 1. A carrier driving means for running and scanning a carrier carrying a print head in a main scanning direction, wherein the carrier driving means is controlled to accelerate the carrier to a predetermined constant speed. In a serial printer that performs print output from the print head and decelerates and stops the carrier when the print output ends to perform printing line by line, the relationship between speed and acceleration according to the data length of one line Based on the formula, a combination of these control times is calculated when the total time of the constant speed control time for controlling the drive of the carrier at a constant speed and the acceleration / deceleration control time for controlling the acceleration and deceleration of the carrier is constant. Of the control time calculating means and the control time calculated by the control time calculating means, whichever has the shorter acceleration / deceleration control time. A serial printer provided with a print control means for performing line printing based on a combination of control times. 2. A carrier driving means for running and scanning a carrier carrying a print head in a main scanning direction, the carrier driving means is controlled to accelerate the carrier to a predetermined constant speed, and at this constant speed. In a serial printer that performs print output from the print head and decelerates and stops the carrier when the print output ends to perform printing line by line, the relationship between speed and acceleration according to the data length of one line Based on the formula, the control time calculation means for calculating a combination of these constant speed control time and the acceleration / deceleration control time that results in the shortest total time, and the control time calculated by the control time calculation means. A serial printer provided with a print control means for performing line printing based on a combination.