JP2882024B2 - Printer overheat prevention device - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for preventing overheating of a printer, and more particularly, to overheating caused by repeated acceleration / deceleration of a carriage motor when so-called short-line printing is continuous. Also, the present invention relates to an apparatus for preventing overheating of a paper feed motor due to continuous line feed operation.

[Prior Art] Conventionally, in a dot matrix type serial printer, a DC motor has been used as a carriage motor. If so-called short-line printing in which the number of print characters per line is several is continuous, the carriage motor may be overheated because acceleration and deceleration are repeated at short intervals.

Therefore, in order to deal with such an overheating problem,
59-87191 and Japanese Patent Application Laid-Open No. 62-234973 have been proposed. A configuration is adopted in which the temperature of the carriage motor is detected by a sensor, and when the temperature exceeds a predetermined temperature, the carriage motor is forcibly executed a cooling operation. It had been.

[Problems to be Solved by the Invention] However, it is necessary to attach a sensor that is used only for detecting such an overheated state, and an increase in the number of parts and an increase in the number of assembling steps have become problems.

In addition, since it depends on the sensitivity of the sensor, if the emphasis is placed on protection of the carriage motor, it is necessary to use a high-sensitivity and expensive sensor, which leads to a problem that the cost is increased. On the other hand, if you try to provide sufficient protection with a sensor that is not so sensitive, it is necessary to set conditions on the safe side, and by performing an overheat prevention operation that is sensitive,
There is a new problem that high-speed printing is not possible.

As described above, the conventional technology of actually detecting the temperature and executing the overheating prevention has a problem that the cost must be tolerated or the speeding up must be abandoned.

The overheat prevention device for a printer according to the present invention solves such a conventional problem and provides a device capable of accurately preventing overheating of the printer without using a sensor and capable of withstanding high-speed operation. It was completed as a technical idea aimed at that.

Configuration of the Invention [Means for Solving the Problems] In order to achieve this object, a printer overheat prevention device according to the present invention, as illustrated in FIG. First correcting means for sequentially correcting the heat generation state of the drive system of the printing means toward the overheating side, and sequentially correcting the heat generation state of the drive system of the printing means to the cooling side from other information relating to the driving frequency of the printing means. A second correction unit; determining that the drive system of the printing unit is overheated when the heat generation state of the drive system corrected by the first correction unit and the second correction unit satisfies a predetermined condition. Overheating determining means for performing the operation, and when the overheating determining means determines that the overheating state is determined, an operation adding means for additionally performing a predetermined operation corresponding to space printing to the drive system of the printing means. Take composition It was.

[Operation] According to the overheat prevention device for a printer of the present invention, the first correction unit sequentially corrects the heat generation state of the drive system of the printing unit to the overheating side based on the information on the driving frequency of the printing unit, and performs the second correction. The means sequentially corrects the heat generation state of the drive system of the printing means toward the cooling side from other information relating to the driving frequency of the printing means. Further, when the heat generation state of the drive system corrected by the first correction unit and the second correction unit satisfies a predetermined condition, and the overheat determination unit determines that the drive system of the printing unit is overheated. Then, the operation adding unit causes the drive system of the printing unit to additionally execute a predetermined operation corresponding to space printing.

That is, instead of directly detecting the overheating state by the temperature sensor, a configuration is adopted in which the heating state of the drive system is sequentially corrected to the overheating side or the cooling side and estimated based on information on the driving frequency of the printing unit. In the estimation, for example, when the drive system is a carriage motor, if the carriage motor is accelerating or decelerating, the heating state is set to the overheating side, and if the carriage motor is driving at a steady speed, the cooling side is set to the cooling side. , Respectively. For this reason, it is possible to execute the overheating prevention operation as scheduled on the desk without variation in the estimation accuracy.

Moreover, since the heat generation state of the drive system is corrected not only on the superheat side but also on the cooling side, it is possible to estimate a heat generation state that is very close to the actual heat generation state of the drive system. Therefore,
Since the safety conditions in the design can be reliably realized, it is extremely suitable for responding to high speed. When a predetermined operation corresponding to the space printing is added by the operation adding unit, the information relating to the driving frequency of the printing unit becomes the second.
The correction means prompts the correction to the cooling side.
For example, the heat generation state is corrected to the cooling side by securing a time during which the carriage motor is driven at a steady speed.
Then, since the correction is made, the overheating determining means cancels the determination of the overheating state, and the printer returns to the normal operation. For this reason, it is not necessary to provide a reset process for stopping the predetermined operation corresponding to the space printing.

Further, in the present invention, as described above, the heat generation state of the drive system can be sequentially corrected to the overheating side and the cooling side from the information on the driving frequency of the printing unit. If a configuration in which the counter is added or subtracted is adopted, the heat generation state can be managed by a single counter.

Embodiment Next, in order to clarify the configuration and operation of the present invention described above, a preferred embodiment of the present invention will be described in detail with reference to the drawings.

First, the configuration of the entire printer will be described with reference to FIG.

The printer 1 is a well-known dot-matrix type serial printer, and includes a platen 3 serving both as a feeder and a receiver for printing paper, a carriage 5 moving in parallel along the platen 3, and a print mounted on the carriage 5. It comprises a head 7, a platen motor 9, a carriage motor 11, and a control device 13 for controlling the drive of the print head 7. The control device 13 is a well-known electronic control circuit having a CPU, a ROM, a RAM, an input / output port, and the like, and performs various operations such as paper feeding, carriage movement, and printing based on various driving programs, control data, and the like. Is controlling.

Next, of the control executed by the control device 13, the processing content of the printer 1 as an overheat prevention device will be described.

FIG. 3 shows a process for preventing the carriage motor 11 from overheating due to continuous short line printing.

This process is executed by a periodic interruption of several tens of msec. First, it is determined whether the carriage motor 11 is accelerating or decelerating (S1). This determination is easily performed by referring to the acceleration / deceleration flag set only while the drive control signal for the carriage motor 11 corresponds to the acceleration / deceleration.

When it is determined that acceleration / deceleration is being performed, a predetermined addition value n1 is added to the acceleration / deceleration coefficient C1 (S2). This addition value n1 is
It is determined in advance based on the amount of heat generated by the carriage motor 11 during acceleration / deceleration.

On the other hand, when it is determined that acceleration / deceleration is not being performed, a predetermined subtraction value n2 is subtracted from the acceleration / deceleration coefficient C1 (S3). This subtraction value n2 is determined in advance from heat radiation conditions when the carriage motor 11 is driven at a steady speed.

When the acceleration / deceleration coefficient C1 is updated in this manner, it is determined whether the updated value is larger than a predetermined threshold N1 (S
Four). If “YES” is determined, the carriage motor 11
Then, an overheating drive signal S10 for additionally executing a space printing operation for 10 columns is output (S5). As a result, a time during which the carriage motor 11 is driven at a steady speed is secured, and the heat generated during this time cools the carriage motor 11. This overheating drive signal
S10 is ignored when the number of lines to be additionally executed is large and a space printing operation cannot be added.
In such a case, since the time required to move at the steady speed is long, sufficient heat radiation is performed, the cooling is naturally performed, and there is no problem even if the space printing operation is not additionally performed.

On the other hand, if it is determined “NO” in the process of S4, the overheating drive signal S10 is not output (S6).

FIG. 4 shows a process for preventing the platen motor 9 from overheating due to the continuous line feed operation continuing for a long time.

This process is also executed by a periodic interruption of several tens of msec, and it is determined whether or not the paper is currently being fed by referring to a flag that is set only while the platen motor 9 is being driven (S11).

When it is determined that the paper is being fed, a predetermined addition value n11 is added to the paper feeding coefficient C2 (S12), and when it is determined that the paper is not being fed, a predetermined subtraction value n12 is subtracted. (S
13). The addition value n11 and the subtraction value n12 are determined in advance based on the amount of heat generated when the platen motor 9 is driven and the amount of heat released when the platen motor 9 is stopped.

When the paper feed coefficient C2 is updated in this way, it is determined whether the updated value is greater than a predetermined threshold N2 (S1).
4) If “YES” is determined, the overheating drive signal S10 for causing the carriage motor 11 to additionally execute a space printing operation for 10 columns is output in the same manner as the processing of S5 described above (S15). If the determination is "NO", the overheating drive signal S10 is not output (S16). Since the platen motor 9 is stopped while the carriage 5 is performing the space printing operation, heat is radiated and cooled here.

As described above, according to the printer 1 of the embodiment, it is possible to accurately estimate the overheating state without disposing the temperature sensor. Further, since the detection is not performed by the sensor, a troublesome problem such as the sensitivity of the sensor, which has been a problem in the past, does not occur. Therefore, as a condition for preventing overheating, a purely thermodynamic design is not required, and a very large safety factor need not be expected, which is extremely convenient for speeding up printing.

In the above embodiment, the print head 7 serves as a printing unit, the carriage motor 11 serves as a drive system,
Reference numeral 13 corresponds to a first correction unit, a second correction unit, an overheat determination unit, and an operation addition unit. In the processing executed by the control device 13, S2 is the first correction unit, S3 is the second correction unit,
S4 is processing corresponding to the overheating determination means, and S5 is processing corresponding to the operation adding means.

Although one embodiment of the present invention has been described above, the present invention is not limited to the above-described embodiment, and various modes can be adopted without departing from the gist thereof.

Effect of the Invention As described above, according to the overheat prevention device for a printer of the present invention, it is possible to accurately prevent overheating of the printer without using a sensor, thereby reducing the number of parts and the number of installation steps. It becomes possible, and the cost can be greatly reduced.

Moreover, since there is no problem in the sensitivity of the sensor, it can be designed based on a pure thermodynamic theory, and it is not necessary to adopt a large safety coefficient, it is suitable for responding to high speed.

Further, it is not necessary to provide a reset process for stopping the predetermined operation corresponding to the space printing, and the process can be simplified.

Furthermore, if a configuration in which the counter is added or subtracted according to whether the heating state of the drive system is corrected to the overheating side or corrected to the cooling side is adopted, the heating state can be managed by a single counter, The configuration of the processing and control system can be further simplified to reduce costs.

[Brief description of the drawings]

FIG. 1 is a block diagram schematically illustrating the configuration of the present invention, and FIG.
FIG. 3 is a block diagram showing the configuration of the printer according to the embodiment, FIG. 3 is a flowchart of overheating prevention processing for a carriage motor, and FIG. 4 is a flowchart of overheating prevention processing for a platen motor. DESCRIPTION OF SYMBOLS 1 ... Printer, 3 ... Platen 5 ... Carriage, 7 ... Printhead 9 ... Platen motor 11 ... Carriage motor 13 ... Control device

Claims (3)

(57) [Claims] A first correction unit for sequentially correcting a heating state of a driving system of the printing unit to an overheating side from information on a driving frequency of the printing unit; and other information on a driving frequency of the printing unit. A second correcting means for sequentially correcting the heat generation state of the drive system of the printing means toward the cooling side;
Correction means; and overheating for determining that the drive system of the printing means is overheated when the heat generation state of the drive system corrected by the first correction means and the second correction means satisfies a predetermined condition. Determining means; and determining that the overheating determining means is in an overheating state,
An overheating prevention device for a printer, comprising: an operation adding unit that additionally executes a predetermined operation corresponding to space printing with respect to a drive system of the printing unit. 2. The overheat prevention device for a printer according to claim 1, wherein said printing means is mounted on a carriage, and said driving system is a carriage motor for moving said carriage. The heat generation state is sequentially corrected to an overheating side when the carriage motor is accelerated or decelerated, and the second correction means sequentially corrects the heat generation state to a cooling side when the carriage motor is driven at a steady speed. Printer overheat prevention device. 3. A method according to claim 2, further comprising a single counter associated with the heat generation state, wherein the first correction means corrects the heat generation state by adding a value of the counter, and wherein the second correction means Correcting the heat generation state by subtracting the value of the counter, wherein the overheating determination means determines that the drive system is in an overheating state when the value of the counter exceeds a predetermined threshold value. 3. The overheat prevention device for a printer according to claim 1, wherein