JP3024363B2 - 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, since there is no need to perform the font ROM 20 and various decorations, the extracted data is directly developed in the output buffer without passing through the work RAM 21. 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 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 structure must be of the greatest common denominator so that the pointer reading from the buffer and the like can be commonly used in each mode, and this has 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 an improved throughput by changing it in real time as needed.

[0007]

SUMMARY OF THE INVENTION A printer according to the present invention has a plurality of input buffers for temporarily holding data received via an interface, and has a plurality of print modes which can be switched at any time. Means for stopping data reception at the time of switching, means for changing an input pointer for managing input of the input buffer to one of the plurality of input buffers, means for resuming data reception, Means for transferring the contents of the input buffer selected by the input pointer before the pointer change to the input buffer after the change of the input pointer; and an output pointer for managing the output of the input buffer on the input buffer after the change of the input pointer. The most important feature is to have means for changing.

[0008]

Since the present invention has the above configuration, an input buffer suitable for each printing mode can be configured in real time 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. As for the arrows, solid lines indicate data and broken lines indicate the flow of commands and signals. 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 28 analyzes data extracted from the input buffer 24 through the output channel 27 and classifies the data into data / command. The analyzed command is sent to the mode determination unit 28, 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 29 sends a mode switching signal to the data analysis unit 28. Data analysis unit 2
8 sends a data transfer stop signal to the interface 22 upon receiving the mode switching signal.
The interface 22 stops receiving data according to the stop signal. On the other hand, since data may remain in the input buffer 24, the data analysis unit 28 transmits a transfer start signal to the data transfer unit 26 to transfer the data in the input buffer 24 to the new input buffer 25. Send. Upon receiving the transfer start signal, the data transfer unit 26 secures an area for the remaining data amount in the input buffer 24 at the end of the input buffer 25. Here, if the area to be secured exceeds the size of the input buffer 25, the data analysis operation is continued until the remaining data amount falls within the size of the input buffer 25. When an area for the remaining data amount can be secured in the input buffer 25, the data transfer unit 26 once issues a data analysis inhibition signal to the data analysis unit 28,
Stop the analysis operation.

The above is the sequence up to immediately before data transfer. Next, the sequence after the data transfer will be described 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 data transfer. Both the input and output pointers point on the area of buffer # 1. From this state, the data transfer unit 26 issues an input pointer change signal to the input channel 23, and the input channel 23 receives the change signal and switches the input pointer to the head address of the input buffer 25.
FIG. 3B shows the state of the buffer after switching. Data input via the interface 22 is stored from this address thereafter. Similarly, the data transfer unit 26 outputs the output pointer change signal to the output channel 27.
Send to The output channel 27 switches the output pointer to the buffer # 2 in response to the pointer change signal.
FIG. 3C shows the state of the buffer after switching. Here, the output pointer is set to an address obtained by subtracting an offset corresponding to the remaining data amount on the buffer # 1 from the last address of the buffer # 2. After updating the input / output pointer as described above, the data transfer unit 26 sends a data transfer permission signal to the interface 22 to restart data reception. Finally, the data transfer unit 26 transfers the remaining data from the input buffer # 1 to the buffer # 2. The state of the buffer after the transfer is shown in FIG. When the transfer is completed, a data analysis permission signal is sent to the data analysis unit 28,
The analysis by the data analysis unit 28 is restarted. This data analysis is started from the data on the address indicated by the output pointer.

The above is the sequence in the case of switching from the buffer 24 (buffer # 1) to the buffer 25 (buffer # 2). The same applies to the reverse case.

As a more detailed explanation, the input buffer in the character mode is a ring buffer # 1, and the input buffer in the bit image mode is a ring buffer # 2. The capacity of the buffer # 1> the capacity of the buffer # 2 The following is an example of a data reception sequence when it is assumed that:

FIG. 4 is a flowchart showing an example of an output sequence from the input buffer. First, it is determined whether the current print mode has changed (step 31). If the current mode changes from the character mode to the bit image mode (step 32), data reception is temporarily prohibited (step 33). It is determined whether the amount of data remaining in buffer # 1 is less than the capacity of buffer # 2 (step 3
4) If the remaining data amount is equal to or larger than the capacity of buffer # 2, data is extracted from buffer # 1 (step 39), and the output pointer is updated (step 40). In this case, data reception is not permitted until the remaining data amount falls within the buffer # 2. If the amount of remaining data is within buffer # 2, the input pointer is changed from buffer # 1 to the start address of buffer # 2 (step 35), and the output pointer is changed from buffer # 1 to buffer # 2 (step 36). . Note that the output pointer is as shown in FIG.
Is changed to the position described using. Thereafter, data reception is resumed (step 37), and the remaining data is transferred from buffer # 1 to buffer # 2 (step 38). Data transfer is performed from the old output pointer to the new output pointer as described with reference to FIG. The buffer switching is thus completed, and thereafter, data reception is performed using the buffer # 2 until the mode switching occurs again.

On the other hand, when it is determined that the mode has changed from the bit image mode to the character mode as a result of the mode determination, the capacity of the buffer # 1> the capacity of the buffer # 2, and
The remaining data is always ready for immediate transfer. In this case, it is only necessary to disable the reception interrupt (step 42), change the input / output pointer (steps 43 and 44), disable the reception interrupt (step 45), and transfer the remaining data from buffer # 2 to buffer # 1 (step 46). , And subsequent data reception is performed using the buffer # 1.

In the above sequence, steps 32 to 38 and steps 32 to 46 are added to the conventional sequence of steps 39 to 40. Thus, the size of the reception buffer can be set for each of the character mode and the bit image mode.

Further, by setting the buffer capacity in the bit image mode to 1 byte, the work of updating the output pointer is omitted, and higher-speed data reception becomes possible. Furthermore, 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 devise further higher speed bit image printing.

An effect similar to the above can be obtained by setting the capacity of the buffer to 256 bytes. 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.

[0021]

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 Data transfer unit 27 Output channel 28 Data analysis unit 29 Mode discrimination unit

Claims (9)

(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. When the input buffer is switched, first, the data reception of the reception interface is stopped, and the remaining reception data already stored in the input buffer at that time is switched by the data transfer unit that controls the flow of the reception data in the input buffer. While the data is transferred to the input buffer of the first printing mode, newly received data is stored directly from the receiving interface into the input buffer of the first printing mode, and the remaining data is stored in the input buffer of the first printing mode. A printer that outputs received data to data interpretation means first. 2. When switching the input buffer, if the data amount of the remaining reception data exceeds the capacity of the input buffer in the switching destination print mode, the data amount is changed to the capacity of the input buffer. 2. The printer according to claim 1, wherein the data is directly transferred to said data interpreting means until the following is reached. 3. 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. 4. The printer according to claim 1, wherein the switching of the print mode is performed according to data to be received. 5. The printer according to claim 4, wherein the plurality of print modes are a character mode including an image developing process of a character code and an image mode for a graphic or the like. 6. The printer according to claim 1, wherein the capacity of the input buffer in at least one print mode is always fixed. 7. Control of 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 in response to switching of the print mode. A method of switching the input buffer, firstly stopping data reception of a receiving interface, and transferring remaining reception data already stored in the input buffer at that time to an input buffer of a switching destination print mode. The newly received data is stored directly from the reception interface to the input buffer of the switching destination print mode, and is output to the data interpretation means from the remaining received data first in the input buffer of the switching destination printing mode. Data control method for printer. 8. When switching the input buffer, if the data amount of the remaining received data exceeds the capacity of the input buffer in the switching destination print mode, the data amount is changed to the capacity of the input buffer. 8. The data control method according to claim 7, wherein said remaining received data is directly transferred to said data interpreting means until the following is reached. 9. The data control method according to claim 7, wherein the print mode is switched according to data to be received.