JPH10254721A - Printing device, interruption request processing method and storage medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a printing device for preventing a specified task, especially a task related to a data reception processing from occupying CPU, and to provide an interruption request processing method and a storage medium. SOLUTION: When printing information from a host computer 1 is received in a state where the priority of an interruption request is set like 'timer interruption > data reception interruption > vertical synchronizing signal interruption', the number of starting times (number of interruption times) on the task started with a strobe signal on an interface as a trigger is counted for prescribed time. It is judged whether the value of an interruption times number counter exceeds a prescribed value or not. When the value of the interruption times number counter exceeds the prescribed number, the setting of priority is changed by exchanging a data reception interruption request and a vertical synchronizing signal interruption request in an interruption control circuit 13.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printing apparatus for performing image forming processing and print output processing based on print information input from a host computer, an interrupt request processing method thereof,
And a storage medium.

[0002]

2. Description of the Related Art FIG. 3 shows an example of a commonly used printing apparatus for performing image forming processing and print output processing based on print information input from a host computer.

Referring to FIG. 1, a printing apparatus 200 includes a CPU 208 for generally controlling the operation of the printing apparatus 200, in particular, page editing and printing processing, a ROM 209 for storing a control program of the CPU 208, and a program for executing various programs. RAM2 used as a work area in the
10, a panel 211 used by the operator to input various settings and notifying the operator of the occurrence of an error by displaying an error, and a timer interrupt request signal for measuring the time and for each fixed period. A timer 212 for outputting, an interface unit 202 connected to the host computer 201 for receiving print information transmitted from the host computer 201, a page buffer memory 203 for storing the received print information, Font memory 2 for storing a character font for referencing the character code of the character code included in the printed information
04, a bitmap memory 205 for expanding character codes and image data by a predetermined method, a parallel / serial conversion unit 206 for converting data (parallel data) expanded in the bitmap memory 205 into serial data, It mainly comprises a recording unit 7 for irradiating a photoreceptor with a light beam to form an electrostatic latent image based on image information composed of serial data obtained as described above, and an interrupt control circuit 213. Each of the above components 202 to 213
Are connected to each other via a bus line 217.
The interface unit 202 includes, for example, a parallel interface represented by a Centronics interface, a serial interface represented by RS-232C, and the like.

[0004] The interrupt control circuit 213 has an interrupt mask register 214, an interrupt priority switching circuit 215, and a priority encoder 216. The interrupt mask register 214 includes a plurality of registers such as a reception interrupt request signal output from the interface unit 202, a timer interrupt request signal output from the timer 212, and a vertical synchronization interrupt request signal output from the recording unit 207. An interrupt request signal is input, and any of the interrupt request signals is masked and input to the priority encoder 215. The priority encoder 215 encodes the input interrupt request signal according to a predetermined priority, and
Input to PU208.

[0005] In the conventional printing apparatus having the above configuration, print information sent from the host computer 201 is stored in the page buffer memory 203 via the interface unit 202.

The method of storing print information in the page buffer memory 203 includes a method of constantly monitoring a receiving port and polling whether data has been received, and a method of interrupting.

Here, a case is considered in which print information is interrupted.

When the print information is received by the interface unit 202, a reception interrupt request signal is sent from the interface unit 202 to the interrupt mask register 214 of the interrupt control circuit 213. Interrupt mask register 214
Inputs a signal corresponding to the received reception interrupt request signal to the priority encoder 215. The priority encoder 215 encodes the request signal in accordance with a predetermined priority and inputs the request signal to the CPU 210. CP
U208 decodes the signal input from the interrupt control circuit 213 and recognizes the priority of the interrupt request. If the priority of the recognized interrupt request is higher than the priority of the task currently being processed, the interrupt request is accepted. That is, the CPU 208 starts the processing of the interrupt processing routine with reference to the interrupt vector table in the ROM 210 which stores the start address of the interrupt processing program corresponding to the interrupt request. At this time, the CPU 208
The register values such as the program counter in the RAM 21
After being saved to the stack in 0 and executing the interrupt processing routine, the register value is returned to a register such as a program counter again. In the interrupt routine, appropriate processing is performed according to the interrupt factor.

FIG. 4 is a timing chart showing the relationship between the input timing of an interrupt request signal and a task started by each interrupt request signal. In the same figure, FIG.
FIG. 4B shows the output timing of the timer interrupt request signal output from the timer 212 at regular intervals. FIG. 4B shows the timing of the reception interrupt request signal output from the interface unit 202 when print information is received. FIG. 4C shows the output timing of the busy signal, and FIG.
(D) shows the output timing of the vertical synchronizing signal as an interrupt signal for starting the print output based on the print information.

FIG. 4E is a timing chart in which the vertical axis indicates the priority of the task activated by each interrupt request signal and the horizontal axis indicates time. In the figure, a task started in synchronization with a timer interrupt request signal generated at regular intervals is referred to as a task A.

The printing apparatus must start printing out an image within a predetermined time in synchronization with a vertical synchronizing signal sent from an engine (not shown) in the recording unit 7. A task that is started by an interrupt request by a signal and starts print output of an image is referred to as a task B.

A task activated by a strobe signal on the interface 202 when print information is received by the interface unit 202 is referred to as a task C. When the task C is activated, the print information is latched by a hardware at a reception port (not shown) of the interface unit 202 by using a strobe signal as a trigger.
, The busy signal is activated to suspend the transmission of print information. The task C reads out the received print information from the reception port of the interface unit 202, stores the read print information in the reception buffer in the RAM 10, and then inactivates the busy signal to enable the host computer 1 to continuously transmit the print information.

[0013]

However, according to the above-mentioned conventional example, when high-speed data transmission from the host computer 201 to the printing apparatus 200 is possible, there are the following problems.

(1) If the priority setting of the interrupt processing is fixed in the order of timer interrupt> data reception interrupt> vertical synchronization signal interrupt, first, as shown in FIG. Time t1 at which the timer interrupt request signal was output
After the processing by the task A is performed, the task B is activated when the vertical synchronization signal is output at the time t2. When the reception interrupt request signal is output at the time t3 immediately after the activation, the data is transmitted. Since the reception interrupt has a higher priority than the vertical synchronization signal interrupt, the task C is started regardless of whether the task B is completed. After that, the CPU 20
When the interrupt request from the interface unit 202 is frequently applied to the CPU 8, the CPU 208 is occupied by the task C activated by the interrupt request, and therefore, the processing must be completed by time t 4. Task B
Is awaited, and a desired operation cannot be expected.

(2) On the other hand, if the priority of the data reception interrupt processing in the interface unit 202 is set low in advance, the task C is kept waiting while another task with a higher priority is being processed. And the data transfer speed between the host computer 201 and the printing apparatus 200 is reduced.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and a printing apparatus capable of preventing a specific task, particularly a task relating to data reception processing, from occupying a CPU, and an interrupt request therefor. It is an object to provide a processing method and a storage medium.

[0017]

According to another aspect of the present invention, there is provided a printing apparatus for performing an image forming process and a print output process based on print information from a host computer. Receiving means for receiving print information from the host computer and outputting a data reception interrupt request; and prioritizing the data reception interrupt request in accordance with the amount of print information sent from the host computer within a predetermined time. Determining means for determining whether the state is to be changed; and changing means for changing the priority of the data reception interrupt request when the determining means determines that the state is to be changed. And characterized in that:

According to a second aspect of the present invention, in the printing apparatus of the first aspect, the determining means counts the number of interrupts due to a data reception interrupt request output from the receiving means within the predetermined time. Thus, the information amount is acquired, and it is determined whether or not the priority of the data reception interrupt request should be changed according to the acquired information amount.

According to a third aspect of the present invention, in the printing apparatus according to the first aspect, the determining unit acquires the information amount by measuring a reception interval of the print information by the receiving unit. It is characterized in that it is determined whether or not the priority of the data reception interrupt request is to be changed according to the amount of information.

According to a fourth aspect of the present invention, there is provided an interrupt request processing method for a printing apparatus which performs an image forming process and a print output process based on print information from a host computer. It is determined whether or not the priority of the data reception interrupt request output from the receiving unit for receiving the print information from the host computer is to be changed according to the information amount of the transmitted print information. When it is determined that the priority is to be changed, the priority of the data reception interrupt request is changed.

According to a fifth aspect of the present invention, in the interrupt request processing method of the fourth aspect, the information amount is obtained by counting the number of interrupts caused by the data reception interrupt request. It is characterized by.

According to a sixth aspect of the present invention, in the interrupt request processing method of the fourth aspect, the information amount is obtained by measuring a reception interval of the print information by the receiving unit. It is characterized by.

A storage medium according to a seventh aspect is a storage medium applied to a printing apparatus for performing image forming processing and print output processing based on print information from a host computer, and is transmitted from the host computer within a predetermined time. A function of determining whether or not the priority of a data reception interrupt request output from a receiving unit that receives print information from the host computer should be changed in accordance with the amount of print information received. And a function of causing a computer to implement the function of changing the priority of the data reception interrupt request when it is determined that the priority should be changed.

[0024]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, an embodiment of the present invention will be described.
This will be described with reference to FIGS.

FIG. 1 is a block diagram showing a configuration of a printing apparatus according to the present embodiment.

Referring to FIG. 1, a printing apparatus 100 includes a CPU 8 for overall control of the operation of the printing apparatus 100, in particular, page editing and print processing, a ROM 9 for storing a control program of the CPU 8, and a program for executing various programs. RAM 10 used as a work area in the system, a panel 11 used by the operator for inputting various settings and notifying the operator of the occurrence of an error by displaying an error, A timer 12 for outputting a timer interrupt request signal to the host computer 1, an interface unit 2 connected to the host computer 1 for receiving print information sent from the host computer 1, and a page for storing the received print information. Refer to the buffer memory 3 and the character code of the character code included in the received print information. Font memory 4 for storing character fonts, a bitmap memory 5 for expanding character codes and image data by a predetermined method, and converting data (parallel data) expanded in the bitmap memory 5 to serial data. A parallel / serial conversion unit 6, a recording unit 7 that irradiates a light beam to a photoconductor based on image information composed of serial data obtained by conversion to form an electrostatic latent image, an interrupt control circuit 13, It is mainly composed of The components 2 to 13 are connected to one another via a bus line 17. The interface unit 2 includes, for example, a parallel interface represented by a Centronics interface, an RS-232
It comprises a serial interface such as C.

The interrupt control circuit 13 has an interrupt mask register 14, an interrupt priority switching circuit 15, and a priority encoder 16. Interrupt mask register 1
Reference numeral 4 denotes a plurality of interrupt request signals such as a reception interrupt request signal output from the interface unit 2, a timer interrupt request signal output from the timer 12, and a vertical synchronous interrupt request signal output from the recording unit 7. , And masks any of these interrupt request signals. The interrupt priority switching circuit 15 switches the priority of the interrupt request signal sent from the interrupt mask register 14. The priority encoder 16 has a predetermined priority,
The input interrupt request signal is encoded and input to the CPU 8.

In the above configuration, the host computer 1
Is sent to the page buffer memory 3 via the interface unit 2. The stored print information is transferred to the bitmap memory 5, where it is developed into bitmap data. The developed print information (parallel data) is converted into serial data that can be processed by the recording unit 7 in the parallel / serial conversion unit 6. The recording unit 7 executes a printing process based on print information as serial data sent from the parallel / serial conversion unit. The page editing process and the printing process are controlled by the CPU 8 according to a control program stored in the ROM 9.

Here, a case will be described in which an interrupt process is executed for print information sent from the host computer 1 to the printing apparatus 100 via the interface unit 2 comprising a Centronics interface.

When the print information is received by the interface unit 2, a reception interrupt request signal is sent from the interface unit 2 to the interrupt mask register 214 of the interrupt control circuit 13. The interrupt mask register 214 inputs a signal corresponding to the received reception interrupt request signal to the priority encoder 16 via the priority switching circuit 15. The priority encoder 16 encodes the input signal according to a predetermined priority, and
Enter

The CPU 8 decodes the signal input from the interrupt control circuit 13 and recognizes the priority of the interrupt. If the recognized priority is higher than the priority of the task currently being processed, Accept the interrupt request. That is, C
The PU 8 refers to the interrupt vector table storing the start address of the interrupt processing program in the ROM 10 and starts the interrupt processing routine. At this time, CP
Register values such as the program counter in U8 are stored in RAM
After the interrupt processing routine is executed, the register value is returned to a register such as a program counter. In the interrupt routine, appropriate processing is performed according to the interrupt factor.

Here, a task started in synchronization with a timer interrupt request signal generated at regular intervals is referred to as a task A.

Further, the printing apparatus synchronizes with a vertical synchronization signal sent from an engine (not shown) in the recording unit 7 to
The print output of the image must be started within a certain period of time. The task that is started by the interrupt request signal by the vertical synchronization signal and starts the print output of the image is task B.

Further, when the printing apparatus receives print information sent from the host computer 1 via the interface unit 2, a task activated by a strobe signal on the interface 2 as a trigger is referred to as a task C.

When the task C is activated, the print information is latched by the hardware by a strobe signal as a trigger at a reception port (not shown) of the interface unit 2, and at the same time, the print information is transmitted from the host computer 1. Busy signal is activated to stop the operation. The task C reads out the received data from the reception port of the interface unit 2 and stores it in the reception buffer in the RAM 10, and then inactivates the busy signal to enable the host computer 1 to continuously transmit print information.

It is assumed that the priority order of the interrupt requests for activating each task among the above-mentioned tasks is set as follows: timer interrupt> data reception interrupt> vertical synchronization signal interrupt.

When a print command is sent from the host computer 1, the CPU 8 starts measuring a predetermined time by a timer interrupt. Then, each time the task C is started in response to the reception interrupt request signal output from the interface unit 2 by receiving the print information, the CPU 8 increments the value of the interrupt counter (not shown) by one.
Thus, the number of interrupts due to the reception of the print information within the predetermined time is counted. By counting the number of interrupts, the amount of print information sent from the host computer 1 can be obtained.

When the counted time reaches a predetermined time, the CPU 8
Determines whether the value of the interrupt counter has exceeded a predetermined value, that is, whether the received information amount has exceeded a predetermined amount. In this determination, if the value of the interrupt frequency counter exceeds a predetermined value, the fact is notified to the interrupt priority switching circuit 15. Upon receiving the notification, the interrupt priority switching circuit 15 switches the order of the data reception interrupt and the vertical synchronization signal interrupt.

On the other hand, if the interrupt counter does not reach the predetermined value within the predetermined time, it can be determined that the data transmission from the host computer is at a low speed. , And sends an instruction to the interrupt priority switching circuit 15 to restore the priority prior to the replacement.

FIG. 2 is a timing chart showing the relationship between the input timing of the interrupt request signal after the priority order has been switched and the task started by each interrupt request signal.
2A shows the output timing of the timer interrupt request signal, FIG. 2B shows the output timing of the reception interrupt request signal, and FIG. 2C shows the output timing of the busy signal. FIG. 2D shows the output timing of the vertical synchronization signal.

FIG. 2E is a timing chart in which the vertical axis indicates the priority of the task after the priority switching and the horizontal axis indicates time.

Time t1 at which the timer interrupt request signal was output
, The task B is started when the vertical synchronization signal is output at time t2 after the processing by the task A is performed. Since the priority of task B is higher than the priority of task C, if a reception interrupt request signal is output at time t3 immediately after activation, the reception interrupt request is suspended and task C is activated. Not done. And task B
Ends at time t4, the suspended task C is activated, and after the print information is fetched, the busy signal is made inactive. Thereafter, if the task B has not been started, the task C is started by receiving the print information sent from the host computer 1.

As described above, according to the present embodiment, the priority order of the data reception interrupt request in the interface unit 2 according to the amount of print information transmitted from the host computer 1 within a predetermined time. Is dynamically changed, it is possible to prevent a specific task from occupying the CPU 8. This allows
It is possible to prevent a desired process from being performed due to waiting for the processing of another task, or to prevent a problem such as deterioration of a data transfer speed between the host computer 1 and the printing apparatus 100.

In this embodiment, the priority order of the interrupt request is changed according to the amount of print information obtained by counting the number of interrupts within a predetermined time. The present invention is not limited to this, and the same effect can be obtained by measuring the data reception interval and changing the priority according to the measured reception interval.

In the present embodiment, for example, only the receiving port of the interface unit 2 is counted, but the output of another plurality of interrupt requests may be counted.

[0046]

As described above, according to the printing apparatus of the first aspect or the interrupt request processing method of the fourth aspect, according to the amount of information sent from the host computer within a predetermined time, It is determined whether or not the priority of the data reception interrupt request output from the receiving unit that receives the print information from the host computer is to be changed, and it is determined that the priority is to be changed. In this case, the priority of the data reception interrupt request is changed, so that the task of receiving print information can be prevented from occupying the CPU. The effect of being able to provide is obtained.

According to the storage medium of the present invention, according to the information amount of the print information sent from the host computer within a predetermined time, the print information is output from the receiving means for receiving the print information from the host computer. A function of determining whether or not the priority of the data reception interrupt request is to be changed; and a function of determining the priority of the data reception interrupt request when it is determined that the priority is to be changed. Since the program for realizing the function to be changed is stored in the computer, the program can be installed in the control device of the printing apparatus, so that the versatility of the printing apparatus can be improved.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration of a printing apparatus according to an embodiment of the present invention.

FIG. 2 is a timing chart showing the relationship between the input timing of an interrupt request signal after the priorities have been switched and tasks started by each interrupt request signal.

FIG. 3 is a block diagram illustrating a configuration of a conventional printing apparatus.

FIG. 4 is a timing chart showing a relationship between input timing of an interrupt request signal and a task started by each interrupt request signal.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Host computer 2 Interface part 7 Recording part 8 CPU 12 Timer 13 Interrupt control circuit 14 Interrupt mask register 15 Interrupt priority switching circuit 16 Priority encoder

Claims (7)

[Claims] 1. A printing device that performs image forming processing and print output processing based on print information from a host computer, a receiving unit that receives print information from the host computer and outputs a data reception interrupt request, Determining means for determining whether or not the priority of the data reception interrupt request is to be changed according to the information amount of the print information sent from the host computer within a predetermined time; and And a change unit configured to change a priority of the data reception interrupt request when it is determined that the priority is to be changed. 2. The method according to claim 1, wherein the determining unit obtains the information amount by counting the number of interrupts by a data reception interrupt request output from the receiving unit within the predetermined time. 2. The printing apparatus according to claim 1, wherein it is determined whether or not the priority of the data reception interrupt request is to be changed. 3. The determining unit obtains the information amount by measuring a reception interval of the print information by the receiving unit, and determines a priority of the data reception interrupt request according to the obtained information amount. The printing apparatus according to claim 1, wherein it is determined whether the state is to be changed. 4. An interrupt request processing method for a printing apparatus that performs image forming processing and print output processing based on print information from a host computer, the information amount of print information transmitted from the host computer within a predetermined time. And determining whether or not the priority of the data reception interrupt request output from the receiving unit that receives the print information from the host computer is to be changed, and changing the priority. And changing the priority of the data reception interrupt request when it is determined that 5. The interrupt request processing method according to claim 4, wherein the information amount is obtained by counting the number of interrupts caused by the data reception interrupt request. 6. The interrupt request processing method according to claim 4, wherein the information amount is obtained by measuring a reception interval of the print information by the receiving unit. 7. A storage medium applied to a printing apparatus that performs an image forming process and a print output process based on print information from a host computer, and stores a print information sent from the host computer within a predetermined time. A function of determining whether or not the priority of a data reception interrupt request output from a receiving unit that receives print information from the host computer is to be changed according to the information amount; and A function of changing the priority of the data reception interrupt request when it is determined that the state to be changed,
A storage medium storing a program to be realized by a computer.