JP3092327B2 - Printer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printer having a function of changing the capacity of an input buffer for holding input data according to a print mode.

[0002]

2. Description of the Related Art Taking a general-purpose dot matrix printer as an example, a normal printer has a character mode for printing character data and a bit image mode for printing images, symbols, and patterns by controlling an image in dot units.
It has two modes that can be switched at any time. FIG. 2 is a block diagram showing the outline. Hereinafter, this block diagram will be described. Various programs for controlling the printer are stored in the program ROM 19,
Shall be controlled by

[0003] First, the printer receives the data sent from the host computer via the interface 11,
The data is stored in the input buffer 12. The data analysis unit 13 takes out data from the buffer 12 and classifies the data into character data, bit image data, decoration commands, print start commands, and other control commands. In the case of the character mode, the extracted data is sent to the character expansion unit 14, and in the case of the command, processing corresponding to each command is performed.
In the case of character data, character image data corresponding to the data is read from the font ROM 20 and is temporarily expanded on the work RAM 21. After that, various necessary decorations are performed on the image data in the work RAM 21, and when all the decorations are completed, the image data is developed at a predetermined position on the output buffer 16. On the other hand, in the case of the bit image mode, there is no need to perform the font ROM 20 and various decorations. The data developed in the output buffer 16 by the above sequence is transmitted to the printing mechanism 18 through the print buffer 17 by using the print start command as a trigger.
And the printing is executed.

However, conventionally, regardless of the print mode, the structure of the input buffer directly related to the data reception / analysis sequence is unchanged. Therefore, in the data reception / analysis sequence, the management of the write pointer to the input buffer and the input The structure has to be the greatest common denominator so that the management of the pointer read from the buffer and the like can be commonly used in each mode, which hinders the improvement of the throughput.

Also, in the bit image mode, a large amount of data is simply expanded directly into the output buffer. Changing the structure of the output buffer is also useful for improving the throughput, but in a system having a limited capacity, There is also a problem that a sufficient capacity for the output buffer cannot be secured depending on the state of the input buffer because the input buffer area presses other storage capacity.

[0006]

SUMMARY OF THE INVENTION The present invention is intended to solve such a problem. The purpose of the present invention is to set the position and size of an input buffer in an optimum state according to the characteristics of each mode. Another object of the present invention is to provide an inexpensive printer with an improved throughput by changing it in real time as needed.

[0007]

According to the present invention, there is provided a printer comprising:
When switching the print mode, the printer also switches the capacity of the input buffer to be used. The received data already stored in the input buffer is transferred to a temporary buffer different from the input buffer and stored. The data to be received is stored directly from the receiving interface to the new input buffer corresponding to the print mode of the switching destination, and the data output is output first from the already received data, and then corresponds to the print mode of the switching destination And outputting the received data stored in the input buffer.

[0008]

Since the present invention has the above configuration, an input buffer suitable for each print mode can be configured in real time for each mode without stopping data reception.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to an embodiment in a printer having two modes, a character mode and a bit image mode.

FIG. 1 is a block diagram showing an outline of the present embodiment. In the arrows, solid lines indicate data, and broken lines indicate signal flows. It is assumed that an input buffer used in the character mode is the input buffer 24, an input buffer used in the bit image mode is the input buffer 25, and both are ring buffers. It is also assumed that the character mode is currently set.

Data sent from the host computer is stored in an input buffer 24 through an interface 22 and an input channel 23. The data analysis unit 27 analyzes data extracted from the input buffer 24 through the output channel 26 and classifies the data into data / commands. The analyzed command is sent to the mode determination unit 28, and the current print mode is determined. As a result of the discrimination, when the mode is changed from the character mode to the bit image mode, the mode discrimination unit 28 inhibits the data reception interrupt, immediately sends a pointer change signal to the input channel 23, and sets the input pointer to the input buffer 24. From the start address of the input buffer 25. Thereafter, the data reception interrupt is enabled, and the normal reception interrupt operation is restarted.

On the other hand, since data may remain in the reception buffer 24, the mode discrimination unit 28 once sends an analysis stop signal to the data analysis unit 27 to stop the data analysis operation, and A transfer start signal is sent to the data transfer unit 29 in order to transfer the data in 24 to the temporary buffer 30. The data transfer unit 29 transfers the remaining data in the reception buffer 24 to the temporary buffer 30 through the output channel 26. When all data has been transferred, the data transfer unit 29
Send a transfer end signal to The mode discriminator 28 receives this signal, sends an output pointer change signal to the output channel 26, changes the output pointer to a temporary buffer, and then sends an analysis start signal to the data analyzer 27, Restart the operation. Thereafter, the data analysis operation is continued until the temporary buffer 30 becomes empty, and when the temporary buffer 30 becomes empty, the data transfer unit 29
Sends a data empty signal to the mode discriminator 28,
The mode determination unit 28 receives the empty signal and sends an output pointer change signal to the output channel 26, and switches the output pointer from the temporary buffer 30 to the start address of the new input buffer 25. This completes the switching from the input buffer 24 to the input buffer 25.

The operation of changing the input / output pointer at the time of buffer switching will be described below in detail with reference to FIG. FIG. 3 shows the movement of the input / output pointer and the remaining data when switching from the buffer 24 (shown as buffer # 1) to the buffer 25 (shown as buffer # 2).

FIG. 3A shows the state of the buffer immediately before switching the buffer. Both I / O pointers are buffer # 1
Point on the area. From this state, the input pointer is first moved to the head address of the buffer # 2 (b).
Immediately thereafter, the reception interrupt is permitted, and the input data received via the interface 22 from the position of the input pointer is stored. On the other hand, the mode determining unit 28
Send a transfer start signal to The data transfer unit 29 receives the signal and transfers the remaining data from the position of the output pointer to the temporary buffer (c). After transferring all data, the output pointer is moved from the buffer # 1 to the head address of the temporary buffer (d), and the data analysis by the data analysis unit 27 is restarted. Thereafter, data is extracted from the temporary buffer until the temporary buffer becomes empty (e). When the temporary buffer becomes empty (f), the output pointer is changed from the temporary buffer to the start address of the buffer # 2, and the switching of the buffer is completed. Thereafter, the data receiving operation is performed using the buffer # 2 until the mode switching occurs again.

The above is the sequence in the case of switching from the buffer 25 (buffer # 1) to the buffer 26 (buffer # 2). The same applies to the reverse case.

As a more detailed description, an example of a data reception sequence when the input buffer in the character mode is assumed to be the ring buffer # 1 and the input buffer in the bit image mode is assumed to be the ring buffer # 2 will be described below. .

FIG. 4 is a flowchart showing an example of an output sequence from the input buffer.

First, it is determined whether or not the current print mode has changed (step 31). If the current mode changes from the character mode to the bit image mode (or vice versa) (step 32), the data reception interrupt is once prohibited (step 33). After changing the input pointer to the head address of the buffer to be switched (step 34), the data reception interrupt is permitted (step 3).
5). Thereafter, the remaining data is transferred from the current output pointer to the temporary buffer (step 36), and when the transfer is completed, the output pointer is changed to the temporary buffer (step 37).

On the other hand, when the mode does not change, the above 3
Steps 3 to 37 are omitted, one-byte data is extracted from the address indicated by the current output pointer (step 38), and the output pointer is updated to the next address (step 39). Finally, if the buffer in which the output pointer is currently located is a temporary buffer (step 40), it is checked whether remaining data remains in the temporary buffer (step 41). If the temporary buffer is empty, the output pointer is deleted from the temporary buffer. The input pointer is changed to the head address of the buffer where the input pointer is located (step 42).

By using the above sequence, the size of the receiving buffer can be set for each of the character mode and the bit image mode. Further, in the embodiment shown in FIG. 2, the data transfer can be speeded up by making the portion enclosed by a dashed line into hardware, and the buffer capacity in the bit image mode is reduced to 1 byte. This saves time and effort in updating the output pointer, and can speed up the data reception operation. In addition, the reception buffer used in the character mode can be used for other purposes as it is. For example, by using the reception buffer for a print buffer, it is possible to further improve the speed of bit image printing.

Note that an effect similar to the case of using the above-mentioned 1-byte buffer can be obtained by setting the capacity of the buffer in 256-byte units. In this case, since the end of the ring-shaped buffer can be checked only by the upper byte, the determination of the seam can be simplified as compared with the case where the size of the buffer is arbitrarily set.

[0022]

As described above, according to the present invention, high throughput can be realized with the minimum capacity without waste. For example, in the character mode, the reception buffer capacity is increased and the host restraining time is shortened, but the bit image is reduced. In the mode, by mutually contradictory buffer configurations such as increasing the throughput by minimizing the capacity of the reception buffer, it is possible to realize performance that could not be realized unless you have a large buffer in advance, at a lower price. it can.

[Brief description of the drawings]

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

FIG. 2 is a block diagram illustrating an outline of a conventional dot matrix printer.

FIG. 3 is a diagram illustrating a state of an input buffer according to an embodiment.

FIG. 4 is a diagram showing a data output sequence as an example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Input interface 12 Input buffer 13 Data analysis part 14 Character development part 15 Bit image development part 16 Output buffer 17 Output interface 18 Printing mechanism 19 Program ROM 20 Font ROM 21 Work RAM 22 Input interface 23 Input channel 24 Input buffer # 1 25 Input Buffer # 2 26 Output channel 27 Data analysis unit 28 Mode discrimination unit 29 Data transfer unit 30 Temporary buffer

Claims (5)

(57) [Claims] 1. A printer for switching a capacity of an input buffer to be used when a print mode is switched, and for received data already stored in the input buffer,
While the data is transferred to and stored in a temporary buffer different from the input buffer, newly received data is stored directly from the reception interface to a new input buffer corresponding to the print mode of the switching destination. A printer which outputs data first, and thereafter outputs received data stored in an input buffer corresponding to the print mode of the switching destination. 2. The printer according to claim 1, wherein after storing the received data in the temporary buffer, the memory of the input buffer storing the received data is released. 3. The printer according to claim 1, wherein the print mode is switched in accordance with a print mode switching signal. 4. The printer according to claim 1, wherein the plurality of print modes are a character mode including a character code image developing process and a bit image mode for a graphic or the like. 5. A data control method for switching a capacity of an input buffer to be used when a print mode is switched,
For already received data already stored in the input buffer, the data is transferred to a temporary buffer different from the input buffer and stored. For newly received data, a new interface corresponding to the print mode of the switching destination is transmitted from the reception interface. Storing directly in the input buffer, and for data output, outputting the received data first, and then outputting the received data stored in the input buffer corresponding to the print mode of the switching destination,
A data control method comprising: