JPH0550689A - Carriage control device - Google Patents

Abstract

PURPOSE:To control a DC motor go that its exothermic temperature does not exceed a tolerable limit temperature level in case the travel distance of a carriage required for printing a single line of data is comparatively shorter, in a printer with a carriage driven by the DC motor. CONSTITUTION:A temperature sensor mounted on a DC motor detects an exothermic temperature. If a detected value reaches a tolerable limit temperature level, and the travel distance of a carriage required for printing a single line of data is shorter than a specified travel distance, the DC motor is allowed to stop for a specified time for each single line of data to be printed in accordance with the length of a travel distance of the carriage required for printing a single line of 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 on a recording medium by driving a carriage with a DC motor.

[0002]

2. Description of the Related Art FIG. 6 shows the construction of a carriage control device of a serial printer to which the present invention is applied. DC motor 1
Is converted into a linear movement of the timing belt 3 via the pulley 2. By pulling with the timing belt 3, the carriage 5 carrying the print head 4 is moved, and printing is performed from the print head 4 to the print medium 8 such as paper. The DC motor 1 is provided with an encoder 6 for position detection.

FIG. 7A shows a drive pattern of the DC motor 1 when printing one line of print data, and FIG. 7B shows a current flowing through the DC motor 1 at this time. Tacc is an acceleration section, and after reaching a predetermined rotation speed, a constant speed section Tcons
Printing is performed while performing constant speed control at t, deceleration control is started after printing is completed, and deceleration is performed in the deceleration section Tbrk. A large torque is required to accelerate and decelerate the carriage 5,
Since the torque generated by the DC motor 1 is proportional to the current value, the acceleration section Tacc and the deceleration section Tbrk as shown in FIG. 7B.
Then, the current value becomes larger than the constant speed section Tconst.

Therefore, the shorter the constant speed section Tconst,
The average current of the DC motor 1 per row becomes large. Further, since the heat generation amount of the DC motor 1 increases as the average current increases, the heat generation amount increases as the print data in one line decreases and the constant speed section Tconst decreases.

If the amount of heat generated increases and the allowable temperature is exceeded due to such continuous printing, the DC motor 1 may be burned. Therefore, in the conventional printer, a high-power DC motor is used in consideration of the case where the print data in one line is small.

[0006]

However, the number of print data in one line is generally about several tens of digits, and for example, it is rare that printing of less than ten digits continues continuously for a long time. If a high-power DC motor is selected in consideration of such a special situation, there is a problem that the DC motor utilization efficiency deteriorates when the number of print digits is large.

The present invention has been made in view of the above points and solves such a problem. An object of the present invention is to increase the efficiency of use of a DC motor by controlling the heat generation temperature of the DC motor so as not to exceed an allowable value. A control device is provided.

[0008]

In order to achieve this object, a carriage control device of the present invention comprises a temperature detecting means for detecting a heat generation temperature of the DC motor, a position detecting means for detecting a position of the carriage, Based on the detected position, the traveling distance of the carriage required for printing one line is obtained, the detected heat generation temperature reaches a preset predetermined temperature, and the obtained traveling distance is preset. When it is shorter than the traveled distance, it is characterized by further comprising control means for suspending the DC motor for a predetermined time each time one line is printed in accordance with the obtained traveled distance.

[0009]

Embodiments of the present invention will now be described in detail with reference to the drawings.

FIG. 1 is a block diagram of a carriage controller showing an embodiment of the present invention. In FIG. 1, the same devices as those of the configuration example shown in FIG. In the figure, reference numeral 7 is a temperature sensor arranged in contact with the DC motor 1 in order to detect the heat generation temperature of the DC motor 1.

FIG. 2 is a control block diagram for controlling the carriage control device having such a configuration. In FIG. 2, reference numeral 10 is a CPU that controls the printer. Reference numeral 11 is a ROM, and in the control program and the present embodiment, the allowable limit temperature Hs of the DC motor 1 (12 in the present embodiment).
0 ° C.), predetermined traveling distance Ss (encoder 6 in this embodiment)
(The output pulse number is 150 pulses), and the relationship between the traveling distance Spe from the stop position of the carriage 5 to the print end position and the rest time shown in Table 1 is stored as a data table shown in Table 1. Reference numeral 12 is a RAM for temporarily storing various data. Reference numeral 18 is a timer C
Timing is performed by the data set by the PU 10.
When the time measurement ends, the timer 18 generates an interrupt signal and C
The PU 10 recognizes the timekeeping by this. Print data from a host device 13 such as a computer is sent to the CPU 10 via an I / F unit (interface unit) 14. The print command is sent from the CPU 10 to the head drive unit 16 via the I / O unit 15, and in response to this, the head drive unit 16 drives the print head 4 to perform printing. The control command for the DC motor 1 that drives the carriage 5 is sent from the CPU 10 through
It is sent to the DC motor drive unit 17 via the unit 15, and the DC motor drive unit 17 drives the DC motor 1 to control it at a predetermined rotation speed. The output pulse of the encoder 6 according to the rotation angle of the DC motor 1 is sent to the CPU 10 via the I / O 15, the position of the carriage 5 is controlled by counting this pulse, and rotation is performed by measuring the pulse cycle. Detect speed. (Hereinafter, the traveling distance of the carriage 5 is represented by the number of pulses of the encoder.) Further, the heat generation temperature data of the DC motor 1 detected by the temperature sensor 7 is I /
It is sent to the CPU 10 via the O unit 15.

The operation of the embodiment of the present invention configured as above will be described with reference to FIG. FIG. 3 is a flowchart showing the operation of printing one line of print data. Here, the operation in which the carriage 5 is stopped at the stop position shown in FIG. 4A and is moved in the direction of the arrow to print the print data "ABCD" is shown.

The CPU 10 develops the head drive data in the RAM 12 according to the print data from the host device 5 and calculates the print area according to the print data. At this time, the traveling distance Spe from the stop position of the carriage 5 to the print end position (final position of the print area) is determined. Here, Spe = 100 pulses [step].

The step is a printing operation. First, the DC motor 1 is driven to start moving the carriage 5. The DC motor 1 accelerates from a stopped state toward a predetermined rotation speed,
After reaching, it is controlled to a predetermined rotation speed. After that, when the print area is reached, the CPU 10 drives the print head 4 based on the head drive data to perform printing. When printing according to the print data is completed, deceleration control is performed and the carriage 5 is stopped [step].

Next, the heat generation temperature of the DC motor 1 is detected by the temperature sensor 7 and compared with the value of the allowable limit temperature Hs stored in the ROM 11, and the heat generation temperature of the DC motor 1 has not reached the allowable limit temperature Hs. If so, proceed to the printing of the next line [step].

On the other hand, if the heat generation temperature of the DC mower 1 has reached the allowable limit temperature Hs in the step, the process proceeds to the step. In the step, the predetermined traveling distance Ss stored in the ROM 11 and the traveling distance Spe determined in the step from the stop position of the carriage 5 to the printing end position Spe.
And Spe is larger than Ss, the process proceeds to the printing of the next line [step].

In step, if the traveling distance Spe from the stop position of the carriage 5 to the printing end position is less than the predetermined traveling distance Ss, the process proceeds to step. In the step, data of the pause time corresponding to the value of Spe (travel distance from the carriage 5 stop position to the print end position) determined in the step is set in the timer 18 by the data table stored in the ROM 11, and the process proceeds to the step. .. Since Spe = 100 here, the rest time is set to 20 msec [step].

In the step, it is judged whether or not the time count for the data set in the step has ended, and if the time count has ended, the process proceeds to the printing of the next line [step].

Next, a method of determining the set value of the predetermined traveling distance Ss and the data table will be described. FIG. 5A shows the relationship between the running distance Spe from the stop position of the carriage 5 to the print end position and the heat generation saturation temperature of the DC motor 1 in one line when printing is continuously performed without providing a pause time. It is a thing. Since the allowable limit temperature for guaranteeing the characteristics of the DC motor 1 used in this embodiment is 130 ° C., the allowable limit temperature Hs for control is 1 in consideration of the margin of detection accuracy and the like.
It was set to 20 ° C. From FIG. 5A, the allowable limit temperature Hs is 12
Since the Spe corresponding to 0 ° C. is 150 pulses, the predetermined traveling distance Ss is set to 150 pulses. When Spe is 150 pulses or less, the average current is reduced by providing a pause time before starting printing of the next line. In the data table, as shown in Table 1, the smaller the value of Spe, the larger the value of the pause time. This is because the energization current of the DC motor 1 is large during acceleration and deceleration and small during constant speed control as described above, and the smaller the value of Spe, the larger the proportion of the acceleration / deceleration time. These can be obtained in advance by experiments.

With the above-described structure and operation, high-speed printing is ensured without a pause in the printing operation until the heat generation temperature of the DC motor 1 reaches the allowable limit temperature Hs. (The carriage operation at this time is shown in FIG. 4B.) On the other hand, the heat generation temperature of the DC motor 1 is the allowable limit temperature H.
When s is reached and the travel distance Spe from the stop position of the carriage 5 to the print end position is smaller than the predetermined travel distance Ss, the heat generation temperature is set to the allowable limit temperature by providing a pause time according to the value of Spe. It is possible to keep it below Hs. (Fig. 4 shows the carriage operation at this time.
It shows in (c). As a result, the heat generation saturation temperature of the DC motor 1 when printing is continuously performed with the distance Spe from the stop position of the carriage 5 to the print end position being constant is shown in FIG.
It becomes like (b).

The printing speed as a printer is slowed by providing the pause time. However, as can be seen from FIG. 5 (b), in the printing with Spe of 150 pulses or more, the continuous printing operation can be performed without the pause time. It is possible. As described above, it is rare that printing with a small number of print digits continues continuously for a long time, and it is possible to configure a print digit number that is frequently used without decreasing the printing speed. Even when printing with a small number of print digits is continued, if the heat generation temperature of the DC motor 1 is within the allowable limit temperature Hs, no pause time is provided and the printing speed does not slow down.

In the present embodiment, the travel distance Spe from the stop position of the carriage 5 to the print end position (final position of the print area) is used as the travel distance of the carriage required for printing one line. The distance traveled from the carriage stop position before the start to the stop position after printing,
It is also possible to use the traveling distance during constant speed control. Further, if the travel pattern is determined, the travel distance and the travel time have a correspondence relationship, so the travel time may be used instead of the travel distance.

[0023]

[Table 1]

[0024]

As described above, according to the present invention, it is possible to control the heat generation amount of the DC motor so as not to exceed the allowable value with a simple structure, and the carriage control device having high utilization efficiency of the DC motor. Can be provided.

[Brief description of drawings]

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

FIG. 2 is a block diagram showing an embodiment of the present invention.

FIG. 3 is a flowchart illustrating a carriage driving operation according to an embodiment of the present invention.

FIG. 4 is a diagram showing a carriage driving operation according to an embodiment of the present invention.

FIG. 5 is a diagram illustrating a heat generation state of a DC motor.

FIG. 6 is a configuration diagram of a conventional printer.

FIG. 7 is a diagram showing a carriage drive pattern and a current supplied to a DC motor.

[Explanation of symbols]

 1 DC Motor 2 Pulley 3 Timing Belt 4 Print Head 5 Carriage 6 Encoder 7 Temperature Sensor 8 Print Medium 10 CPU 11 ROM 12 RAM 13 Host Device 14 I / F Unit 15 I / O Unit 16 Head Drive Unit 17 DC Motor Drive Unit 18 Timer

Claims (2)

[Claims] 1. A carriage control device having a carriage on which a print head is mounted and a DC motor for driving the carriage, comprising: temperature detecting means for detecting a heat generation temperature of the DC motor; and position detection for detecting a position of the carriage. And a traveling distance of the carriage required to print one line based on the detected position, the detected heat generation temperature reaches a preset temperature, and the determined traveling distance is preset. The carriage control device further comprises: a control unit that suspends the DC motor for a predetermined time each time one line is printed according to the calculated travel distance. 2. The storage means for storing in advance a predetermined number of rest time data corresponding to the predetermined time according to the traveling distance of the carriage, and a rest time according to the obtained traveling distance. The carriage control device according to claim 1, further comprising a correction unit that reads data from the storage unit and corrects the predetermined time at a time indicated by the read pause time data.