JP3024362B2 - 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 bit image mode, the extracted data is directly expanded in the output buffer without passing through the work RAM 21. The data developed in the output buffer 16 by the above sequence is sent to the printing mechanism 18 through the print buffer 17 with 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 receiving / analyzing sequence is unchanged. Therefore, in the data receiving / analyzing sequence, the management of the write pointer to the input buffer and the input The management of reading pointers from the buffer and the like had to be performed using a structure of the greatest common denominator that can be commonly used in each mode, and this hindered the improvement in throughput.

In the bit image mode, since a large amount of data is directly expanded in an output buffer, it is useful to change the structure of the output buffer to improve the throughput. However, in a system having a limited capacity, an input buffer may be used. 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 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 improved throughput by changing the printer at any time.

[0007]

A printer according to the present invention has an input buffer for temporarily holding data received via an interface, has a plurality of print modes that can be switched at any time, and switches modes at the same time. It is most important to newly provide means for stopping data reception at the time when the input buffer becomes empty, means for changing a pointer for managing input / output of the input buffer when the input buffer becomes empty, and means for resuming data reception. Characteristics.

[0008]

Since the present invention has the above configuration, an input buffer suitable for each printing mode can be configured for each mode.

[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. For convenience, it is assumed that the input buffer used in the character mode is the input buffer 24 and the buffer used in the bit image mode is the input buffer 25, and it is assumed that the input buffer is currently in the character mode state.

The data sent from the host computer is stored in an input buffer 24 (input buffer # 1) through an input channel 23 via an interface 22. The data analysis unit 28 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 29, and the current print mode is determined. As a result of the determination, when the mode is changed from the character mode to the bit image mode, the mode determination unit 2
9 sends a mode switching signal to the data analyzer 28. The data analyzer 28 sends a data transfer stop signal to the interface 22 at the time of receiving the mode switching signal. The interface 22 stops receiving data according to the stop signal. Since data may remain in the input buffer 24 even when the data transfer is stopped, the data analysis unit 28
The data analysis operation is continued until there is no more data inside. When there is no more data in the input buffer 24, the data analyzer 28 sends a pointer change signal to the pointer manager 27. The pointer management unit 27 changes the input channel 23 and the output channel 24 according to the pointer change signal, and switches the input buffer from the buffer 24 to the buffer 25. After switching the buffer, the pointer management unit 27 sends a switching end signal to the data analysis unit 28. The data analyzer 28 receives this signal and sends a data transfer permission signal to the interface 22. Interface 2
2 receives this signal and restarts the receiving operation from the host computer.

The above is the sequence in the case of switching from the buffer 24 to the buffer 25, but the same applies to the reverse case.

FIGS. 3 and 4 are flow charts showing examples of data reception sequences of the parallel interface when the input buffer in the character mode is a ring buffer and the input buffer capacity in the bit image mode is 1 byte. Buffer # 1 indicates a ring buffer used in the character mode, and buffer # 2 indicates a 1-byte buffer used in the bit image mode.

FIG. 3 shows an output sequence from the input buffer. First, it is determined whether the current print mode is the character mode or the bit image mode (step 31).
Buffer # if current mode is bit image mode
It is determined whether or not data remains in Step # 1 (Step 32). If data remains, the data is taken out from the buffer # 1 (Step 36). In this case, data reception is prohibited until the buffer # 1 becomes empty. Data buffer #
If it does not remain in 1, it is determined whether or not there is data in the buffer # 2 (step 33). If data is in buffer # 2, buffer # 2
Is retrieved (step 34), and reception is permitted (step 35).

On the other hand, in the character mode, it is first determined whether or not data remains in the buffer # 2 (step 3).
7) If there is any remaining, data is taken out from buffer # 2 (step 34), and reception is permitted (step 3).
5). If there is no data remaining in the buffer # 2, it is determined whether there is data in the buffer # 1 (step 38). If not, the process loops until data is input. Buffer # 1
, The data is taken out from the buffer # 1 (step 39). Since this input buffer # 1 has a ring-like structure, a seam check is performed before updating the output pointer (step 40). At the time of output, the buffer is scanned in reverse, so the seam check checks whether the buffer has passed the beginning. If the value exceeds the head of the buffer, the output pointer is initialized to the end address (step 41). If not, the output pointer is updated by -1 (step 42). Finally, it is determined whether the immediately preceding state is the buffer full state (step 43). If the buffer state is full, the reception is prohibited and the reception permission processing is performed to restart the reception (step 44).

In the above sequence, step 32
Bit image mode from step to step 35 and step 37
When comparing with character modes ranging from to 44, 4
The portion from 0 to 43 is a load in the character mode when using the ring buffer. In the bit image mode, since this part can be omitted, faster data analysis is possible.

FIG. 4 shows an input interrupt sequence to the reception buffer. At the stage when data is received from the host computer, a reception interrupt is applied, and this sequence starts. In this sequence, first, the printer is brought into a busy state, and the receiving operation is temporarily stopped (step 45). Next, the mode is determined (step 46). If the mode is the bit image mode, the data is stored in the buffer # 2 (step 47).
End the interrupt. If the mode is the character mode, the data is stored in the buffer # 1 (step 48), and the seam of the buffer is checked (step 49). At the time of input, the buffer is scanned in the forward direction, so it is checked whether the end of the buffer has been exceeded. If the input pointer has exceeded the end of the buffer, the input pointer is initialized to the start address (step 50). If not, the input pointer is updated by +1 (step 51), and finally a buffer full check is performed (step 52). If the buffer is full, data reception is prohibited, and if not, data reception is permitted (step 5).
3) End the interrupt. In the above sequence, when comparing the bit image mode and the character mode in the same way as at the time of output, the portion from step 49 to step 53 is the load of the character mode, and this portion can be omitted in the bit image mode. Higher speed data reception becomes possible.

Further, by setting the buffer capacity in the bit image mode to 1 byte, the reception buffer used in the character mode can be diverted to other uses as it is. Can be devised to further increase the speed.

The effect similar to the above is obtained by reducing the buffer capacity by 2
It can be obtained in units of 56 bytes. In this case, since the seam check of the ring-shaped buffer can be performed using only the upper byte, determination of the seam can be simplified as compared with a case where the size of the buffer is arbitrarily set.

[0020]

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 contradicting buffer configurations such as increasing the throughput by minimizing the capacity of the receiving 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 flowchart illustrating an embodiment.

FIG. 4 is a flowchart illustrating an example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 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 21 Work RAM 22 Interface 23 Input channel 24 Input buffer # 1 25 Input buffer # 2 26 Output Channel 27 Pointer analysis unit 28 Data analysis unit 29 Mode discrimination unit

Claims (10)

(57) [Claims] 1. A printer in which an input buffer that can be secured with an arbitrary capacity is prepared corresponding to each of a plurality of print modes, and the input buffer to be used is also switched according to the switching of the print mode. And a pointer management unit for controlling input / output of data in the input buffer using one input pointer and one output pointer prepared for each input buffer. The input buffer is switched using the pointer management unit. 2. The printer according to claim 1, wherein the operation is performed. 3. When the input buffer is switched, data reception of the receiving interface is first stopped, and the remaining received data already stored in the input buffer at that time is directly transferred from the input buffer to the data interpreting means. 3. The printer according to claim 1, wherein data to be newly received is directly stored in the input buffer of the switching destination print mode from the reception interface. 4. The printer according to claim 1, wherein after the input buffer is switched, the input buffers other than the input buffer in the switching destination print mode are released from being reserved. 5. The printer according to claim 1, wherein the switching of the print mode is performed according to data to be received. 6. The printer according to claim 5, wherein the plurality of print modes are a character mode including a character code image developing process and an image mode for a graphic or the like. 7. The printer according to claim 1, wherein the capacity of the input buffer in at least one print mode is always fixed. 8. A data control method for a printer provided with an input buffer that can be secured with an arbitrary capacity corresponding to each of a plurality of print modes, wherein the change of the print mode is detected, and A printer data control method that switches the input buffer to be used. 9. When the input buffer is switched, data reception of the receiving interface is first stopped, and at that time, the remaining received data already stored in the input buffer is directly transferred from the input buffer to the data interpreting means. 9. The data control method according to claim 8, wherein the newly received data is directly stored in the input buffer in the switching destination print mode. 10. The data control method according to claim 8, wherein the switching of the print mode is performed according to data to be received.