JPH0550690A - Carriage control device - Google Patents

Abstract

PURPOSE:To control a DC motor so that its exothermic temperature does not exceed a specified temperature level in the 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:An exothermic temperature is detected by a temperature sensor installed on a DC motor. If the detected temperature reaches a specified 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 travel distance is corrected to a length which is larger than the specified travel distance.

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 traveling pattern of the carriage 5 when printing one line of print data, and FIG. 7B shows a current flowing through the DC motor 1 at this time. Tacc is the acceleration section, and after reaching the specified speed, the constant speed section Tconst
Printing is performed while performing constant speed control with, deceleration control is started immediately after printing is completed, and deceleration is performed in the deceleration section Tbrk. A large torque is required for accelerating and decelerating the carriage 5, and the torque generated by the DC motor 1 is proportional to the current value. Therefore, as shown in FIG. 7B, the acceleration section Tacc and the deceleration section Tbrk have a constant speed section Tconst. The current value becomes larger.

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 control 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-output DC motor is selected on the assumption of such a special situation, there is a problem that the use efficiency of the DC motor is deteriorated 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 a DC motor, a position detecting means for detecting a position of a carriage, and the detecting means. 1 based on the position
When the travel distance of the carriage required for printing a line is obtained, when the detected heat generation temperature reaches a preset predetermined temperature, and when the obtained travel distance is shorter than the preset predetermined travel distance, And a controller that corrects the calculated travel distance to a travel distance equal to or greater than the predetermined travel 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 carriage controller.
Is. Reference numeral 11 is a ROM, which stores the control program and the values of the allowable heat generation temperature Hs of the DC motor 1 and the predetermined traveling distance Ss in this embodiment. Reference numeral 12 is a RAM for temporarily storing various data. 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. A control command for the DC motor 1 that drives the carriage 5 is sent from the CPU 10 to the DC motor driving unit 17 via the I / O unit 15, and the DC motor driving unit 17 drives the DC motor 1. DC motor 1
The output pulse of the encoder 6 according to the rotation angle of
The position of the carriage 5 is managed by counting the pulses sent to the CPU 10 via the O section 15. (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 sent to the CP via the I / O unit 15.
Sent to U10.

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, as shown in FIG. 4A, the carriage 5
Represents the operation of moving in the direction of the arrow and printing the print data "ABCD" from the state of stopping at the position shown in the figure.

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 is fixed. Here, Spe = 100 pulses [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 heat generation temperature Hs stored in the ROM 11, and the heat generation temperature of the DC motor 1 has not reached the allowable heat generation temperature Hs. If so, proceed to the step [step].

In step, the deceleration start distance Sb is the value of Spe determined in step (Sb = Spe = 100 pulses)
Set to. The deceleration start distance Sb is a travel distance from the stop position of the carriage 5 to the start of deceleration control after the printing is completed [step].

On the other hand, if the heat generation temperature of the DC motor 1 has reached the allowable heat generation 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 greater than Ss, the process proceeds to step [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 step, the deceleration start distance Sb is set to the value of the predetermined traveling distance Ss (Sb =
Ss) (step).

When the deceleration start distance Sb, which is the traveling distance from the stop position of the carriage 5 to the start of deceleration control after printing is completed, the process proceeds to step. In the step, first, the DC motor 1 is driven to start the movement of the carriage 5. The DC motor 1 accelerates from the stopped state toward the set speed, and is controlled to a constant speed after the set speed is reached. 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, the process proceeds to step [step].

In step, it is determined whether or not the moving distance of the carriage 5 has reached the value of Sb set in step. When the carriage 5 travels by Sb, the process proceeds to step, where deceleration control is performed and the carriage 5 is stopped.

Next, a method of determining the set value of the predetermined traveling distance Ss will be described. As described above, the current supplied to the DC motor 1 is large during acceleration and deceleration and small during constant speed control.
Therefore, the shorter the traveling distance Spe from the stop position of the carriage 5 to the print end position is, the larger the average value of the energizing current per line is, and the higher the heating temperature of the DC motor 1 is. FIG. 5 shows the relationship between the heat generation saturation temperature of the DC motor 1 in the case where printing is continuously performed with a constant traveling distance Spe from the stop position of the carriage 5 to the print end position in one line.
It shows in (a). For example, when the traveling distance Spe from the stop position of the carriage 5 to the print end position is 100 pulses, the heat generation saturation temperature of the DC motor 1 is 130 ° C. If the allowable heat generation temperature of the DC motor 1 is 120 ° C., S
In the continuous printing operation with pe of 150 pulses or less, the DC motor 1 may be burned due to heat generation. Therefore, the allowable heat generation temperature Hs is set to 120 ° C. and the predetermined traveling distance Ss is set to 150 pulses. It should be noted that this can be obtained in advance by experiments.

With the above configuration and operation, in the printing operation until the heat generation temperature of the DC motor 1 reaches the allowable heat generation temperature Hs, deceleration control is performed immediately after the printing is completed to ensure high speed printing (carriage operation at this time). Figure 4 (b)
Shown in. The horizontal axis represents the traveling distance, and the vertical axis represents the carriage speed. ), When the heat generation temperature of the DC motor 1 reaches the allowable heat generation temperature Hs 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 deceleration start distance Sb is traveled predetermined. By setting the value of the distance Ss and lengthening the time (distance) of constant speed traveling, it becomes possible to suppress the heat generation temperature to the allowable heat generation temperature Hs or less. (The carriage operation at this time is shown in FIG.
Shown in. As a result, the heat generation saturation temperature of the DC motor 1 when printing is continuously performed with the running 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). In this embodiment, the deceleration start distance Sb is set to the value of the predetermined traveling distance Ss (Sb = Ss) in the step, but for example, the temperature H lower than the allowable heat generation temperature Hs is set.
When controlling to t, the deceleration start distance Sb may be set to a value St larger than the predetermined traveling distance Ss.

The printing speed of the printer is slowed down by lengthening the time of constant speed running.
As can be seen from (b), in the printing with Spe of 150 pulses or more, the continuous printing operation can be performed without prolonging the constant speed running time. 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 continues, if the temperature is within the allowable heat generation temperature Hs, the deceleration control is started immediately after the printing is completed, and therefore the printing speed does not slow down.

In order to improve the print speed throughput, printing may be performed during carriage deceleration control. At this time, the distance from the stop position of the carriage 5 to the deceleration control start position may be used instead of the travel distance Spe from the stop position of the carriage 5 to the print end position.

Further, generally, the printer has a plurality of print modes having different print densities, and the print speed (carriage speed) also differs depending on each print mode. Therefore, since the current supplied to the DC motor 1 also varies depending on the print mode, the relationship between the print mode and the predetermined traveling distance Ss is shown in Table 1
It can be dealt with by changing the value of the predetermined traveling distance Ss according to the print mode. The carriage speed is shown in parentheses. Since the average current per line of the DC motor 1 is smaller as the carriage speed is slower, in Table 1, the predetermined traveling distance Ss is set to a smaller value as the carriage speed is slower.

In this embodiment, as the travel distance of the carriage required for printing one line, the deceleration start distance Sb, which is the travel distance from the carriage stop position before the start of printing to the start of deceleration control after the end of printing, is used. However, in addition to this, it is also possible to use the travel distance from the carriage stop position before the start of printing to the stop position after the end of printing, or the travel 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.

[0026]

[Table 1]

[0027]

As described above, according to the present invention, it is possible to perform control so that the heat generation amount of the DC motor does not exceed the allowable value with a simple structure, and the carriage control device with 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 Printing 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

Claims (3)

[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. A carriage control device comprising: a control unit that corrects the obtained travel distance to a travel distance that is equal to or greater than the predetermined travel distance when the travel distance is shorter than the predetermined travel distance. 2. The control means, when the predetermined temperature is an allowable heat generation temperature of the DC motor, corrects the obtained travel distance to the predetermined travel distance, and the predetermined temperature is less than the allowable heat generation temperature. In this case, the carriage control device according to claim 1, further comprising a correction unit that corrects the obtained traveling distance to a distance longer than the predetermined traveling distance. 3. The storage means stores in advance a predetermined number of travel distance data corresponding to the predetermined travel distance according to the print density of the print head, and the travel distance according to the print density. Read the data,
The carriage control device according to claim 1, further comprising: a correction unit that corrects the predetermined traveling distance based on the traveling distance indicated by the read traveling distance data.