JPH0954662A - Method and device for printing multi-valued data - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the method and device for multi-valued data printing which can be used while host equipment is connected without reference to its low performance. SOLUTION: Data transfer from the host equipment to the multi-valued data printer having no frame memory is performed preferentially from a bit which is high in importance in one dot. Only the MSBs (1-n) of data of one horizontal scanning line are transferred first, the 2nd bits from the MSBs are transferred by one line (n+1 to 2n), and similarly the transfer is repeated successively up to the LSBs. After a prescribed time (maximum transfer time) is passed, the number of bits (number of gradations) of one dot which is already transferred at present is compared with the set least number of data bits (number of gradations) and when data more than the least number of data bits are transferred, it is decided that the data transfer is normal. On a reception side, '0' is added to untransferred bits to prepare print data as if all bits were received, and the data are printed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multi-valued data printing apparatus for printing based on multi-valued data transferred from a host device without having a frame memory.

[0002]

2. Description of the Related Art Conventionally, a multi-valued data printing device such as a printer for full-color printing performs printing based on multi-valued print data transferred from a host device such as a personal computer.

FIG. 6 schematically shows an example of the data structure of such multivalued print data. As shown in the figure, as for the print data, the print data for one line in the main scanning direction is pixel 1, pixel 2, pixel 3, pixel 4, ..., Pixel n.
And each pixel is configured as a maximum of n pieces of pixel information, and the information amount of each one pixel (hereinafter referred to as 1 dot) is from the MSB (most significant bit) to the LSB (least significant bit) the number of bits b (for example, b = 8 is 8 bits). In this case, transfer of print data from the host device is
In either case of serial transfer or parallel transfer, first the information of the first dot of the image data (bit information MSB (1) of dot 1 in FIG.
(B) is transferred, and then the information of the second dot (bit information MSB (b + 1) of dot 2 in the figure to LSB) is transferred.
(2b) is transferred, and then the information of the third dot (bit information MSB (2b + 1) to LS of dot 3 in the figure) is transferred.
B (up to B (3b)) is transferred, and this is repeated until the end dot n of one line, and the transfer of print data for one main scanning line is completed. Then, the transfer for one line is repeated in the sub-scanning direction to transfer the print data for one page.

In such a printing operation, in a printing apparatus having no frame memory, the transfer speed of the print data sent from the host device is the case where the receiving side (printing apparatus) has some buffer. However, if this is not a buffer having a sufficient size, the host device side is required to have a print data transfer speed corresponding to the print speed on the receiving side. In general, such a printing apparatus prints by using the print data sent from the host device as it is, so that the printing speed is fast, while the host device converts all the image data from the image data in which the image code and the character code are mixed. After unfolding, every line in the main scanning direction,
Since the dot information of the image data is line-sequentially transferred in the sub-scanning direction, the transfer rate of the print data tends to be slow. For example, the output data of the printer is 300 dp
i (dots / inch) and the transfer speed of the host device is 150 dpi, the output data to be printed by the printer is twice as fast in the main scanning direction as the input data transferred from the host device. , Twice in the sub-scanning direction, that is, four times as many in total, which makes it impossible to transfer print data in time.

As described above, if printing data cannot be continuously received from the host device during printing, the printing device side cannot print. If the supply of print data is interrupted midway before printing for one page is completed after printing is once started in this manner, for example, a thermal transfer printing type printer is likely to stop in the middle of printing. In a printing device with a printing process that causes trouble, even if the printing process is subsequently restarted based on the printing data that has been started to be supplied, the printing data is interrupted and thermal restart is discontinued at the restarted part. As a result, non-uniform gradation and discontinuous lines or deviations on the printing surface occur, which results in the inconvenience that a good printing result cannot be obtained.

Therefore, a printer having a frame memory and receiving the print data for one page from the host device in the frame memory to start printing to avoid the above-mentioned inconvenience is practical. Has been converted.

Further, in the printing apparatus having no frame memory, while receiving the print data transferred from the host device, the print output based on the received print data is performed in synchronization with the reception of the print data. Since the above-mentioned inconvenience will occur if the transmission of the print data of is interrupted, either limit the connected host device to a host device with a sufficiently high processing speed so that the print data will not be interrupted during printing, or A dedicated high-speed interface is provided for printing.

[0008]

However, since the frame memory having the above-mentioned frame memory is extremely expensive, there is a problem that the price of the entire printing apparatus increases. Further, since the frame memory has a large circuit configuration, it is not suitable for a small-sized printing apparatus, and there is a problem in this respect that the design is restricted.

Further, the printing apparatus having no frame memory is basically provided with the host device in real time with the amount of print data necessary for performing the printing process as described above, even if the printing apparatus has a buffer having a certain capacity. Need to be sourced from. Since the supply speed of the print data depends on the processing speed of the host device, the host device prohibits the interrupt during the transfer of the print data for one page or transfers the print data as a single task of the print data transfer process. Will be devoted to. In any case, application to a printing apparatus having no frame memory is limited to a host device having a processing speed above a certain level. However, since there are various types of host devices and not only those with high processing speed, if the processing speed of the connecting host device is limited to high speed as described above, the host that can be selected on the printer side There is a problem that the type of equipment is limited and the usage efficiency of the printing device is reduced.

However, even if reversible data compression is performed in order to reduce the amount of print data to be transferred, it is often the case that a high compression rate cannot be obtained for image data. Therefore, the transfer rate was expected. However, there is a problem that the problem cannot be solved so much and the above-mentioned problem solving cannot be dealt with.

Further, even if a dedicated (special) interface is provided to perform high-speed processing, the general-purpose printer port normally provided in the host device cannot connect the interface of the special standard, and therefore the host device side Therefore, new investment of peripheral devices for connecting the interface of the special standard is required, which causes a new problem that it is troublesome and expensive.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned conventional circumstances,
It is an object of the present invention to provide a multi-valued data printing method and device which can surely reduce the amount of print data to be transferred (reduce the transfer rate) and connect and use a host device without selecting its function.

[0013]

First, according to the invention described in claim 1, multivalued data is printed on a multivalued data printing apparatus having no frame memory based on multivalued print data transferred from a host device. Applies to printing method.

According to the multivalued data printing method of the present invention, only the bit information having a high degree of importance is transferred from the host device to the multivalued data printing device among the information of one pixel for each main scanning line.

Then, for example, as described in claim 2, 1
A sequence of sequentially repeating the transfer corresponding to one main scanning line from the bit information having a high degree of importance among the pixel information to the bit information having a low degree of information, and the time required for the repeated transfer of one line of the main scanning. A procedure for comparing the permissible time that the multi-value data printing device can receive in order to process the print data for one line of main scanning, and the amount of information in one pixel of one line of main scanning that is repeatedly transferred and preset. The procedure for comparing the minimum amount of information in one pixel and the time required for the transfer when the amount of information in the one pixel reaches the minimum amount of information in the one pixel. If the time has been reached, the procedure of determining that the transfer of one line of the main scanning that has been repeatedly transferred is normal, and repeating the above when the amount of information in one pixel reaches the minimum amount of information in the one pixel. Turning If the time required for the transmission has not reached the receivable permissible time, the untransferred information in one pixel is added and transferred to determine that the transfer of the print data of the main scanning 1 line is normal. And when the amount of information in one pixel has not reached the minimum amount of information in one pixel and the time required for the repetitive transfer has reached the receivable allowable time, one main scan line is printed. And a procedure for determining that the data transfer is abnormal.

Further, for example, as described in claim 3, the amount of information in one pixel for one main scanning line which is repeatedly transferred by the time it is determined that the transfer of the print data is normal is subsequently transferred. It further has a procedure of setting the transfer information amount in one pixel for each line of the main scanning. Further, for example, claim 4
As described above, the method further includes a procedure of appropriately changing the minimum amount of information in one pixel.

Next, the invention according to claim 5 is applied to a multivalued data printing apparatus having no frame memory for printing based on multivalued print data transferred from a host device.

The multi-value data printing apparatus of the present invention is configured to transfer only the information of high importance among the information of one pixel of the transferred print data for one main scanning line.

Then, for example, as described in claim 6, 1
Means for sequentially and repeatedly receiving transfer of one line of main scanning from information of high importance to information of low information among pixel information, and time required for this repeated reception and printing of one line of main scanning A means for comparing a receivable permissible time to be processed, a means for comparing the information amount in one pixel of one line of the main scanning, which is repeatedly received, with a preset minimum information amount in one pixel, When the amount of information in one pixel reaches the minimum amount of information in one pixel, if the time required for the repetitive reception reaches the receivable allowable time, the print data for one main scanning line is printed. Means for determining that the reception is normal, and the time required for the repeated reception when the amount of information in the one pixel reaches the minimum amount of information in the one pixel has not reached the allowable receivable time. If there is 1 pixel Means for additionally receiving unreceived information to determine that the reception of the print data for one line of the main scanning is normal, and the amount of information in one pixel is the minimum amount of information in one pixel. If the time required for the repeated reception has reached the receivable allowable time when it has not arrived, it is configured to determine that the reception of the print data for one main scanning line is abnormal. It

In addition, as described in claim 7, for example, the amount of information in one pixel for one main scanning line, which is repeatedly received by the time it is determined that the print data is normally received, is subsequently received. It further comprises means for setting the amount of received information in one pixel for each scanning line, and means for appropriately changing the minimum amount of information in one pixel as set forth in claim 8, for example. Is further configured.

[0021]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing the arrangement of a color thermal printer according to the first embodiment. The host device 10 shown in the figure is a data processor such as a personal computer, and transfers print data to the color thermal printer 11 via an external bus (interface cable) 10a.

In the figure, the color thermal printer 1
1 includes a data controller 12, a timer 13, a memory controller 14, a memory A15, a memory B16, an image processing unit 17, an MPU (micro processing unit) 18, and a TPH (thermal printing head) 19.

The MPU 18 is a central processing unit,
Parameters such as the print size, the enlargement / reduction size, and the minimum number of effective data described later are given to the required blocks to control each unit. The MPU 18 is also configured to receive the above parameters from the host device unit 10 via the external bus 10a.

The timer A13 is the data controller 12
It is reset by the timer reset signal 12a input from the and starts measurement of the transferable time of the print data per main scanning line. Then, the count-up signal 13a that is the measurement result is output to the data controller 12. A timer is provided in the host device 10 as well, and the host device 10 controls the number of transfer bits of print data by collating the transferable time of one line with the actual transmission time. There is.

The data controller 12 is the host device 1
The print data transferred (received) from 0 in the bit slice described later is sequentially developed into bit information (see FIG. 6) for each dot (pixel) in a format that can be processed by the image processing unit 17 in the subsequent stage, and the predetermined time is passed. After the lapse of time, the developed bit information for each dot is written in the memory A15 via the memory controller 14. In addition, the data controller 12
Is the bit information (printing information) for each dot written above.
Is read via the memory controller 14, and the read print information is output to the image processing unit 17.

The memory A15 is a toggle memory having a capacity for storing print information for two main scanning lines. When the print information received from the host device 10 is being written on one surface, the memory A15 is on the other surface. When the print information already written is output to the image processing unit 17 and the output is completed,
One side is switched from the writing side to the reading side,
The other side is switched from the read side to the write side.

The image processing unit 17 performs image processing such as edge enhancement, magnification conversion, γ correction, etc. on the print information input via the memory controller by using the memory B16 as a working memory, and the image processing is performed. TP the completed print information
Output to H19.

The TPH 19 is a print head having a large number of heat generating elements, and selectively heats the heat generating elements according to print information to melt or sublimate the ink of the ink ribbon by the heat generation, and the melting or sublimation thereof. The formed ink is transferred to a sheet, and the image transferred from the host device 10 to the print data is reproduced on the sheet.

FIG. 2 shows a transfer mode of print data (image data) transferred from the host device 10. The structure of the print data shown in the figure is the same as the structure of the print data shown in FIG. 6, and the number of dots (pixel number) of one line in the main scanning direction is n, and the number of bits forming one dot (pixel information The numbers are shown as b. However, in this case, the print data transfer mode is different from that in FIG. That is, as shown in FIG. 2, the transfer order of the print data in this case is not every dot, but first, in the main scanning direction, from the first dot which is the first dot to the nth dot which is the last dot. 1 bit of MSB (most significant bit) of is cut out and transferred. Then, similarly, 1 in the main scanning direction
Only the second 1 bit from the MSB of each dot from the dot to the nth dot is cut out and transferred. Next, similarly, cutting out and transferring the third 1 bit from the MSB is sequentially repeated from the MSB to the LSB (least significant bit) side. This 1-bit cutout (bit slice)
Sets the data of each dot to 1 each time bit slice is performed.
This can be executed by shifting only the bits and bit-slicing the transferred MSB and transferring it.

As described above, in this example, bits of high importance (large amount of information) in 1-dot data are preferentially transferred, and this transfer is repeated a plurality of times in the order of importance. Of course, instead of sending only the MSB first in bit slices, the upper 2 bits may be sent first, and the number of bits to be collectively transferred in priority can be set arbitrarily.
The point is to transfer the bit of high importance in one dot first, and to transfer the remaining data of one dot after that in a plurality of times.

Next, the operation of transmitting and receiving the above-mentioned print data in the first embodiment will be described with reference to the flowcharts of FIGS. 3 and 4. In this process, 8 bits are transferred in parallel. Further, although not particularly shown and described, it is assumed that the transfer of parameters and the like is normally and normally performed, and only the transfer of print data will be focused and described.

First, FIG. 3 is a flowchart of print data transmission by the host device 10. This processing is
This is executed by a printer driver (not shown) of the host device 10. Although not shown in particular, the printer driver also includes a timer B, a sub-scanning counter yctt, a timer B reset permission flag tmst, a bit counter tonet, a main scanning counter xctt, a loop flag i, and a transfer buffer buffer. For example, it is provided by setting an area in a built-in memory. The printer driver performs processing using these counters and flags, the minimum number of data bits Tth, the maximum transfer time TM1 of one line, and the like. Further, in this processing, the number of dots in one main scanning line is n, and the number of sub-scanning is m. Hereinafter, this processing will be described based on the flowchart of FIG.

In the flow chart of FIG. 3, when an image data transmission command is issued from the control unit in the host device 10, the printer driver firstly causes the sub-scanning counter yct.
t is cleared to "0", and the timer B reset permission flag tmst is set to "1" (step S1). As a result, the first line of the main scan is set and
The timer B is ready to start timing.

Then, "7" is set in the bit counter tonet (step S2). As a result, the first bit cutout position is set to the MSB of each dot. "(Number of bits representing gradation) -1" is set in the bit counter tonet,
In this embodiment, since one dot is composed of 8 bits, "7" is set as described above. Bit counter t
As will be described later, the value of "onet" is decremented by "1" and changed from "7" to "0" each time the transfer of each 1 bit for one main scanning line is completed. And "7" is M
SB indicates “SB”, and “0” indicates LSB.

Following the above processing, the main scanning counter xctt is further cleared to "0" (similarly, step S
2). As a result, the position of the head dot of one main scanning line is specified. The value of this main scanning counter xctt "xct
When “t” is “0”, the leading dot (1
(Nth dot)
Is the end dot of the main scanning line (nth dot)
Corresponding to. The value "xctt" of the main scanning counter xctt is "8" each time data of 8 dots is transferred by bit slice once, as described later.
It is incremented and updated so that the position of the leading dot of the next 8 dots to be processed is designated.

Then, the loop flag i is set to "7" (also step S2). The loop flag i is set to "(external data bus width) -1". Since the present embodiment has a configuration of 8-bit parallel transfer, "7" is set as described above. It This controls the number of bits of transfer data.

After the above, referring to the value "xctt" of the main scanning counter xctt, the value "xctt" of the main scanning counter xctt is "n-1" or more which specifies the position of the last dot of one line of the main scanning. It is determined whether or not it is shown, that is, whether or not the print data by bit slice has been transferred for one main scanning line (step S3).

Then, the value "x" of the main scanning counter xctt
When "ctt" does not exceed the value "n-1" corresponding to the end dot, the print data has not yet been transferred for one main scanning line (S3 is N), and in this case, the steps described below. The processes of S4 to S12 are repeated. The series of processes of steps S4 to S12 is a process of transferring the print data of one line of the main scanning for each bit width of the external bus 10a, that is, for each 8 bit width of "0" to "7" in this example.

In this series of processing, first, "0" is set in the transfer buffer "buft" (step S4), and then,
A predetermined bit of a predetermined dot in one main scanning line currently being processed is stored in a predetermined bit position of the transfer buffer buft (step S5). This processing is further performed in step S5.
It will be described in -1 to S5-5.

First, the "xctt + (7-i)" th dot data (bit string, hereinafter simply referred to as dot) in the main scan one line currently being processed is read (step S5-).
1). This is within the bit width of the external bus 10a, that is, 1
This is a process of reading a dot on one main scanning line having data to be stored at a bit position (7-i) to be currently processed within a parallel signal width (8 bits) transferred at one time. This dot position should be currently processed within the parallel signal width (8 bits) at the leading dot position "xctt" of the 8 dots to be currently processed, which is sequentially counted and indicated by the main scanning counter xctt as described above. Bit position "7-i"
It is obtained by adding. In the first processing in this routine, i = 7 as described above (7-
i = 0), so the first dot read is
It is the leading dot of 8 dots to be currently processed, which is indicated on the main scan by the value "xctt" of the main scan counter xctt.

Subsequently, the "tonet" th bit is read from the MSB of the read dot (step S).
5-2). As described above, MSB is designated by tonet = 7, and LSB is designated by tonet = 0. As a result, in this processing, the bits to be taken out in the current processing cycle are read by the bit slice from the bit positions in the above-mentioned 1 dot which are sequentially counted (decremented) by the bit counter tonet.

Next, the bit just read is shifted to the left by "i" bits (step S5-3). As a result, the “tonet” th 1-bit grayscale data from the MSB is moved to the position corresponding to the array in the parallel signal width (8 bits). In the first processing in this routine, since i = 7, a shift of 7 bits brings the first data to the position corresponding to the left end (MSB) in the parallel signal width (8 bits).

Subsequent to the above, "0" is set to the lower bit vacated by the above movement (shift) (step S).
5-4). This prevents the occurrence of indefinite data in the empty lower bits.

Finally, the above data is added to the transfer buffer buft (step S5-5). The above processing is repeated as described later, and the transfer buffer buf
At t, 1-bit data extracted by bit slices from predetermined 8 dots on one main scanning line are sequentially arranged.

As described above, in the step S5, the print data of one line of the main scanning corresponds to the bit width (8 bits in this example) of the external bus 10a, and each dot has 1 bit, that is, 8 bits in total. Taken out.

Following the above, it is judged whether or not the dot just processed is the end dot of one line of main scanning (step S6). The reason for repeating the same determination as that performed in step S3 described above is as follows. That is, in the case where the number of main scanning dots n is not divisible by the transfer bit width "8", when the process advances and the process of the trailing end of one line of the main scanning is started, the routine of step S4 and thereafter is executed. As will be described later, the loop flag i is sequentially decremented and the above step S5 is repeated, so that the processing of the dots on one line of the main scanning progresses sequentially. , The main scan 1 line may be completed before all 8 bits to be transferred are filled with data. At this time, an error occurs when the processing is continued in an attempt to complete the 8-bit data array of the parallel signal to be transferred. To prevent this error from occurring,
The determination in step S6 is performed every time the processing for one dot is completed.

If it is determined in step S6 that the processing has not yet reached the end dot of one line of main scanning (S6 is N), it is further determined whether the loop flag i is "0". Yes (step S7). If it is the first time to enter this routine, i = 7 (S7 is N). Therefore, in this case, after decrementing the loop flag i by "1" (step S8), the process returns to step S5, and steps S5 to S5. Repeat S8. As a result, the 8-bit data array process to be transferred proceeds.

Due to this progress, i = 0 in step S7.
When, the 8-bit data array to be transferred is completed (S7 is Y), and in this case, the content of the timer B reset permission flag tmst is determined (step S9). Further, in step S6, when the processing cycle of the main routine advances and the processing of the trailing end of the main scanning one line is started and the processing dot is the end dot of the one main scanning line (S6 is Y). , Immediately proceeds to step S9.

The timer B reset permission flag tmst is
As described above, since it is set to "1" in the first step S1, the first process of this routine (first main scan 1
In the processing of the first 8 dots of the line), the timer B reset permission flag tmst is "1" in step S9 (Y in S9). Therefore, in this case, the timer B is reset (step S10). This gives the first 8
The time measurement by the timer B is started in synchronization with the start of bit data transfer.

Next, the timer B reset permission flag tms
"0" is set to t (also, step S10). As a result, the reset of the timer B, which has started the above time counting, is prohibited. That is, until the processing of one line of main scanning is completed, in the subsequent processing cycle, "tms"
It is determined that "t" = 0, and thus step S10 is not performed and step S11 described later is immediately performed.

Then, the contents of the transfer buffer bump are transferred to the color thermal printer 11 (step S1).
1). As a result, 1 bit obtained by bit-slicing each of 8 dots being processed for one main scanning line becomes a parallel signal of 8 bits in total, and is output from the host device 10 to the color thermal printer 11.

Then, the main scanning counter xctt is set to "8".
Is added (step S12). As a result, the main scan 1
The dot position next to the previously processed 8 dots of the line is designated.

Then, the process returns to step S3. In step S3, it is again determined whether or not the value "xctt" of the main scanning counter xctt indicating the next designated dot position exceeds the value "n-1" indicating the last dot of one main scanning line. If the value does not exceed the value "n-1" indicating the trailing dot (S3 is N), steps S4 to S1 are performed again.
2 and step S3 are repeated, whereby the output process of the print data by the bit slice in units of 8 dots from the first dot to the last dot of one line of the main scanning proceeds.

In step S3, the main scanning counter xct
If the value of t exceeds the value indicating the position of the trailing dot of one line of the main scanning (S3 is Y), then in this case, the timer B
Is compared with the preset maximum transfer time TM1 of one line (step S13). The maximum transfer time TM1 for one line corresponds to the print processing time for one main scan line of the color thermal printer 11.

According to the determination by the comparison in step S13,
When the elapsed time of the timer B has not exceeded the maximum transfer time TM1 (N in S13), it is determined that the data transfer can be continued, and then the bit counter tonet.
Is "0", that is, whether the bit slice has advanced to the LSB (step S14).

If "tonet" ≠ "0" (S
14 is N), it is determined that there is still an untransferred bit in one dot, the bit counter tonet is decremented by "1", and the bit position for bit slicing is set to LSB.
One by one, the main scanning counter xctt is cleared to "0" to specify the leading dot position of one main scanning line, the loop flag i is set to "7" to set the transfer data width, and Returning to step S3, the above-mentioned step S
The processes of 3 to S12 are repeated again.

As a result, the next 1 bit of each dot in one line of main scanning is sequentially transferred by 8 bits for each bit slice. That is, as long as the elapsed time of data transfer is within the maximum transfer time TM1, pixel information (gradation data) is transferred by bit-slicing bit by bit from the MSB of each dot on the same line to the LSB side.

When “tonet” = “0” in step S14 within the maximum transfer time TM1 (Y in S14), all 8 bits of 1-dot gradation data have been transferred. In this case, the value "yctt" of the sub-scanning counter yctt is the final number of sub-scanning "m-
1 "is determined (step S1)
6). If it is not the final number (S16 is N), the timer B reset permission flag tmst is set to "1", so that the timer B starts counting the elapsed time from the beginning, and the sub-scanning counter ycttt. Is incremented by "1", so that the next main scan 1
The line is designated (step S17), and the process returns to step S2 described above. As a result, the above-described transfer processing is similarly performed for the next main scanning line.

If the elapsed time measured by the timer B exceeds the maximum transfer time TM1 for one line (S3 is Y) in the determination in step S13, then the number of transferred bits (8- "tonet") is determined. ) Has reached or exceeded the preset minimum data bit number Tth (step S18). If the number of transferred bits has reached or exceeded the minimum number of data bits Tth (Y in S18), the process proceeds to step S16. As a result, every time the maximum transfer time TM1 for one line elapses, a predetermined minimum number of data bits Tth is reached within this time.
If the above bit information (gradation information) has been transferred, the above-described data transfer continues in the main scanning line order.

When the value "yctt" of the sub-scanning counter yctt indicates the final sub-scanning number "m-1" in step S16 (Y in S16), the data transfer for one page is completed. In this case, the data transfer process ends normally.

On the other hand, when the elapsed time exceeds the maximum transfer time TM1 and the number of transferred bits does not reach the minimum number of data bits Tth (N in S18), the host computer is used for the printing process of the color thermal printer 11. It is determined that the transfer rate of the device 10 is not in time, that is, both functions are not compatible, and in this case, appropriate error processing such as notification and warning is performed (step S19).

The minimum number of data bits Tth is 2
As long as the number of bits can express the gradation in a decimal number, it may be appropriately determined according to the required image quality.
When expressing with 28 gradations, the minimum number Tth of data bits is “7”.

Next, FIG. 4 is a flow chart of a print data receiving process by the color thermal printer 11. A process of receiving print data transmitted from the host device 10 by the color thermal printer 11 will be described with reference to FIG. In this process, the data controller 12 shown in FIG. 1, under the control of the MPU 18, other than the timer A shown in FIG. 1, a sub-scanning counter ycta, a timer A reset permission flag tmsa, which are not particularly shown,
The bit counter tonea, the reception buffer bufa, the main scanning counter xcta, and the loop counter i (separate from the above-described loop flag i on the host device 10 side) are set in a built-in memory to perform processing. Also in this process, the number of dots in one main scanning line is n, and the number of sub-scanning is m. Hereinafter, description will be given based on the flowchart of FIG.

First, when image data (print data) can be received, the sub-scanning counter ycta is cleared to "0", and the timer A reset permission flag tmsa is set to "1".
Is set (step S31). As a result, the first line of the main scan is set and the timer A is ready to start counting.

Then, "7" is set in the bit counter tonea (step S32). In the bit counter tonea, as in the case of the transfer processing by the host device 10 described above, “(number of bits representing gradation) −
"1" is set, and in this example, one dot has an 8-bit configuration, so "7" is set. This bit counter tonea also changes from "7" to "0" by decrementing by "1", and "7" indicates MS.
B indicates “0” and LSB indicates LSB.

Subsequently, the main scanning counter xcta is further cleared to "0" (similarly, step S32). As a result, the position of the head dot of one main scanning line is specified.
In this case also, the value "xcta" of the main scanning counter xcta
"0" corresponds to the leading dot of the main scanning 1 line, this value sequentially increases, and "n-1" corresponds to the trailing dot of the main scanning 1 line. Also, this main scanning counter xct
The value "xcta" of a is incremented by "8" each time data of 8 dots is received once, as will be described later, thereby designating the position of the first dot within the 8 dots to be processed next. .

Next, in step S33, the arrival of print data is awaited (N in S33), and it is confirmed that the print data is received and stored in the reception buffer bufa (S
33 is Y), and then the timer A reset permission flag tm
It is determined whether or not sa is "1" (step S
34), if it is "1" (S34 is Y), the timer A is reset (step S35). This gives the first 8
When the bit print data is received, the time measurement by the timer A is started. As described above, the timer B on the host device 10 side
Starts timing with the transfer of the first 8-bit print data. As described above, in this example, the timer A is activated by using the first 8 bits of the transfer from the host device 10 as a reference signal. The timer B of 10 is synchronized.

Subsequently, the timer A reset permission flag tm
Set sa to "0" (also step S3
5). As a result, the resetting of the timer A, which has started the above time counting, is prohibited until the reception of print data for one main scanning line to be processed is completed. That is, main scan 1
Until the processing of the line is completed, "tmsa" = 0 is determined in step S34 in the subsequent processing cycle, whereby the processing of step S35 described above is not performed and the processing of step S36 described later is performed immediately.

In step S36, the loop counter i is cleared to "0". As a result, the start position of the 8-bit array is designated. Subsequently, the reception data stored in the reception buffer bufa is sequentially read and stored in the writing surface of the memory A15 (hereinafter referred to as a table buffer) at a predetermined bit position of a predetermined dot in one line of the main scan currently being processed (step). S37). In this process, first, the "i" th bit designated by the loop counter i is read from the MSB of the 8-bit received data stored in the receive buffer bufa, and the read received data is currently being processed. MSB to “i” of the “xcta + i” -th dot designated by the main-scanning counter xcta and the loop counter i in one main-scanning line
This is the process of embedding (storing) at the th bit position.

Continuing from the above, the dot position "xcta +" on the main scan 1 line corresponding to the 1 bit just processed is
"i" is the position "n-1" of the end dot of the main scanning line 1
It is determined whether or not (step S38). this is,
When the above process is repeated as described later,
When the number of dots n set as one main scanning line is not divisible by the bit width "8" of the transfer data as described above, the last transfer data of 8 bits of one main scanning line is , "0" is added to the bits of the remainder, but not all are valid data.
This determination is performed.

If the 1 bit just processed does not correspond to the trailing dot of the main scanning 1 line in this judgment (N in S38), the next processing is continued in order to continue the processing of the main scanning 1 line. By referring to the value of the loop counter i, it is determined whether or not all the 8-bit reception data has been read from the reception buffer bufa and stored in the memory A15 (step S39). Then, the value "i" of the loop counter i =
If it is not 7 (N in S39), all the valid 8 bits have not been transferred yet. In this case, the value of the loop counter i is incremented by "1" to specify the next bit position (step S40), above step S37
Return to

As a result, steps S37 to S40 are repeated, and the reception data of 8 bits in the reception buffer bufa, that is, 8 bits from MSB (i = 0) to LSB (i = 7).
1-bit data for dots is stored in a predetermined address of the table buffer of the memory A15.

In this way, the 8 bits of the reception buffer bufa are sequentially written in the table buffer of the memory A15, and the determination in step S39 becomes "i" = 7 (Y in S39), and the process proceeds to the next step. Again, it is determined whether or not the dot position "xcta + 7" on the main scanning 1 line to which the processed 1 bit corresponds is the end dot position "n-1" of the main scanning 1 line (step S
41).

When the 1 bit does not correspond to the end dot of the main scanning 1 line (N in S41), the value of the main scanning counter xcta is set to continue the processing of the main scanning 1 line. After incrementing by "8" to specify the dot position next to the currently processed 8 dots in one main scanning line (step S42), the above step S3 is performed.
Return to 3.

As a result, the steps S33 to S described above are performed.
42 is repeated, and one line of main scanning is every 8 dots,
First, one bit is embedded from the MSB side. Then, in step S41, when the processed 1 bit is embedded in the end dot of one line of the main scanning (Y in S41), the process proceeds to the next step S43. If the processed 1-bit corresponds to the last dot of one main-scanning line in step S38, the process immediately proceeds to step S43.

In step S43, the time measurement (elapsed time) of the timer A13 is referred to. If the elapsed time does not exceed the predetermined maximum reception time TM2 for one line (S43 is N), the process can be continued. Then, it is determined whether the bit counter tonea is "0", that is, whether the bit embedded in each dot has reached the LSB (step S45).

If "tonea" ≠ "0" (N in S45), it is determined that there are still bits to be embedded in one dot, and the main scanning counter xct is first determined.
After a is cleared to "0", the head dot position of one line of main scanning is designated, the bit counter tonea is decremented by "1", and the next embedded bit position is advanced to the LSB side by one (step S46). , Step S3 described above
Return to 3.

As a result, steps S33 to S46 are repeated, and the bits of each dot in one main scan line are
It is sequentially embedded from the LSB side. On the other hand, in step S43, when the elapsed time measured by the timer A13 exceeds the maximum reception time TM2 of one line (S43 is Y), it is determined that a predetermined amount of print data is written in the table buffer, and the memory is stored. After confirming the completion of reading the print data from the read surface of A15 (hereinafter referred to as the back buffer) (step S47), the surface of the memory A15 that was the front buffer is set as the back buffer and the surface that was the back buffer is set as the front buffer. Switch to the buffer (step S48).

As a result, M of high importance for each dot
The print data for one main scanning line, which is sequentially captured from the SB side to the LSB side within the maximum reception time TM2 of one line with a receivable capacity, is formed by the image processing unit 1 shown in FIG.
The image is processed by 7 and printed by TPH 19. In the memory A15, the writing of data to the front buffer and the reading of data from the back buffer proceed simultaneously while arbitrating so that write data and read data do not collide.

Subsequent to the above, the value of the sub-scanning counter ycta is referred to (step S49), and the sub-scanning counter yct is referenced.
When the value "ycta" of a is not "m-1" (S49
N), it is judged that the reception of the print data for one page is not completed yet, and in this case, the timer A reset permission flag tmsa is set to "1", and the print data of the new main scanning one line is set. After preparing to start timing for reception (step S50), the process returns to step S32.

As a result, steps S32 to S50 are repeated, and the receiving process for each main scanning line progresses line-sequentially in the sub-scanning direction. Then, in step S49,
The value "ycta" of the sub-scanning counter ycta is "m-1".
When (YES in S49), the reception of the print data for one page has ended, and in this case, this reception processing ends. As described above, in the present embodiment, the transmission and reception of the print data are executed while the receiving side recognizes the data bit number of the transmitting side by the two timers of the receiving side and the transmitting side.

The maximum transfer time TM1 of one line used on the transmission side and the maximum reception time TM2 of one line used on the reception side are basically the same time. However, it is necessary to make adjustments in consideration of the program configuration, hardware configuration, timer accuracy, and the like. In other words, the period from the set time of the two timers to the determination time of the elapsed time measured by the timer needs to be equal on the transmitting side and the receiving side.

In the present embodiment, the cycle to see the timer is
Transfer (or receive) 1 bit for 1 line as described above
However, the time error from the count start time of the timers on the transmission side and the reception side to the determination time is extremely small compared to the transfer (or reception) time of 1 bit 1 line. Therefore, the error becomes a problem when it becomes necessary to make a determination before and after the timer A and the timer B exceed the maximum reception time TM2 and the maximum transfer time TMl, respectively. That is, if only one of the timer A and the timer B exceeds the maximum reception time TM2 or the maximum transfer time TM1, they will not be synchronized with each other. In such a case, the following method is used. You may do it.

First, on the transfer side, the value of the timer B is read at the last bit transfer of the 1-line transfer. At this time, when the timer B is about to soon exceed the maximum transfer time TMl, or when only a short time has passed since then, a wait is put in, and the last data of the line is transferred after the measured time of TM1 + t1 is reached. To do so. Specifically, when the time x of the timer B is in the range of (TM1-t1) <x <(TM1 + t1), the wait is put. Where t1
Is the maximum error that can occur between the sending and receiving timers. By performing the processing in this way, it becomes possible to achieve synchronization under any conditions.

It is also possible to add one control signal indicating the end of data transfer of one line without using a timer and synchronize with this signal. Further, in the above embodiment, the transfer is performed by bit slice, but the present invention is not limited to this, and a plurality of bits may be packed and transferred. This means that, for example, when one dot has an 8-bit structure, the number of gradations that can be represented by this is 2 ⁸ , that is, 256 gradations. However, if a print quality of at least 16 gradations is desired, The minimum number of data dots that satisfies this is "4". Therefore, first, information capable of representing 16 gradations, that is, 4 bits is preferentially transmitted. Assuming that the external data bus has an 8-bit width, in this case, the data to be transmitted first is the upper 4 bits of the first dot and the upper 4 bits of the second dot. In this way, 4 bits per dot are sent as a pack, and one main scanning line is sequentially transferred. Here, if the transfer time of one main scanning line does not meet the specified time, a transfer error occurs, but if the transfer time is within the specified time,
Then, the lower 4 bits are backed up and transferred in the same manner as the upper bits, or transferred in bit slices to utilize the surplus time. With this configuration, printing can be performed with gradation up to the performance limit of the host device in accordance with the performance of the host device side.

Further, the transfer is carried out before the actual transfer processing is started, the amount of data per main scan line that can be transferred is checked, and the actual transfer is performed efficiently based on this result. You can also This will be described below as a second embodiment.

The structure of the second embodiment is similar to that shown in FIG. The configuration of print data before transfer is also the same as the configuration shown in FIG. Next, the processing operation will be described.

FIG. 5 is a flow chart of print data transmission by the host device in the second embodiment. This process is also executed by the printer driver of the host device. Further, similarly to the case of the first embodiment, a timer, a sub scanning counter, a bit counter, a main scanning counter, a loop flag, a transfer buffer and the like are used. Further, the minimum number of data bits Tth, the maximum transfer time TM1 of one line, etc. are preset.

In the figure, first, necessary parameters and the like are initialized (step S61). Next, all the print data of one line of the main scanning is transferred by the bit slice similar to that performed in the first embodiment (step S62). Then, in the transferred print data, the number of bits per dot that can be transferred without causing a timer error is returned to the thermal printer, and the dot number is registered in the register p.
(Step S63).

Next, the value of the register p is compared with the minimum data bit number Tth (step S64). If the value of the register p is smaller than the minimum data bit number Tth (S64 is Y), it is not worth printing with the gradation of the number of bits indicated by the register p. Therefore, in this case, a transfer error occurs. Yes (step S65). This means that a desired image cannot be obtained with the transfer performance of this host device.

On the other hand, in step S64, the register p
Is equal to the minimum number of data bits Tth,
If it is more than that (Y in S64), it means that the required image quality condition is satisfied. In this case, the transfer of print data described below is executed.

First, the value of the register p is checked, and "p" = 1
It is determined whether or not (step S66). And
If “p” ≠ 1 (N in S66), it is possible to transfer at least 2 bits per dot,
Therefore, in this case, first, the MSB per dot is
From the side, "p" bits are packed (collectively) and transferred (step S67). In this way, the bits in one dot are collectively transferred as long as transfer is possible, so that the maximum transfer time of one line can be efficiently used. Then, within the time allowed for this efficiency improvement, the remaining "mp" lower bits are transferred bit by bit in the bit slice in order to transfer according to the time margin (step S68). ).

When the maximum transfer time for one line has elapsed, the value of the sub-scanning counter is checked to determine whether the print data for one page has been completed (step S6).
9) If not completed yet (S69 returns N), the parameters for processing the main scanning direction are initialized in order to transfer new print data for one main scanning line (step S7).
0), the above steps S66 to S69 are repeated. As a result, the transfer of print data in the sub-scanning direction proceeds.

Further, in the determination of step S66,
If "p" = 1, only 1 bit per dot can be transferred (Y in S66). Therefore, in this case, transfer is performed by bit slice (step S70).
Then, the process proceeds to step S69.

If the transfer of the print data in the sub-scanning direction progresses and eventually the value of the sub-scanning counter indicates the end of the print data for one page in step S69, the process is ended. .

In step S68, the bit slice transfer is used for printing with the gradation of the maximum capacity of the host device in use. However, if there are multiple gradations of 8 bits or more, it is difficult to determine the difference of one gradation, but when there are about four gradations, the difference of one gradation is large. Therefore, if it is difficult to change the number of gradations for each line, it is preferable not to perform the process of step S68.

[0097]

As described above, according to the present invention,
Since the print data is transmitted / received within the transferable time range of one main scanning line by the bit slice, it is possible to eliminate the transfer error during the printing of multi-valued data, which occurs due to the difference in performance between the host device and the printer. Any type of host device can be selected on the side of the printer, and the efficiency of use of the printer is improved. Further, similarly, even if any low performance host is used, the minimum multi-color printing can be performed using the color thermal printer, which is convenient.

Further, since the minimum number of bits per dot required for gradation expression is set in advance and the minimum number of bits is transferred, it is possible to transfer the minimum number of bits even if the transfer performance is low. In this case, the host device can be selected, and therefore the types of host devices that can be selected are expanded, and the usage efficiency of the printing device is improved.

Further, since the range of types of usable host equipment is widened and the host equipment is rarely selected on the printer side, it is not necessary to provide an interface of a special standard on the host equipment side. The cost of the entire system is reduced.

Further, since pack transfer is performed according to the transfer capability between the host device and the printing device confirmed before printing is started, more efficient data transfer can be realized.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a color thermal printer according to a first embodiment.

FIG. 2 is a diagram showing a transfer form of print data (image data) transferred from a host device.

FIG. 3 is a flowchart of print data transmission processing by a host device.

FIG. 4 is a flowchart of print data reception processing by a color thermal printer.

FIG. 5 is a flowchart of print data transmission by the host device of the second embodiment.

FIG. 6 is a diagram schematically showing a conventional multi-valued print data transfer method.

[Explanation of symbols]

 1, 2, 3, m dot data 10 host device 10a external bus (interface cable) 11 color thermal printer 12 data controller 13 timer 14 memory controller 15 memory A 16 memory B 17 image processing unit 18 MPU (micro processing unit) 19 TPH (Thermal Printing Head)

Claims (8)

[Claims] 1. A multi-valued data printing method for causing a multi-valued data printing apparatus having no frame memory to print based on multi-valued print data transferred from a host apparatus. Main scan 1
A multi-valued data printing method characterized in that only bit information having a high degree of importance is transferred among information of one pixel for each line. 2. A procedure of sequentially repeating the transfer corresponding to one main scanning line from bit information having a high degree of importance in the information of one pixel to bit information having a low degree of information, and the repeated main scanning one line. A procedure for comparing the time required for transfer with the permissible time that the multi-valued data printing device can receive in order to process print data for one line of main scanning; Of the amount of information in the pixel and a preset minimum amount of information in one pixel, and the time required for the transfer when the amount of information in the one pixel reaches the minimum amount of information in the one pixel. When the receivable permissible time has been reached, the procedure of determining that the transfer of one line of the main scan repeatedly transferred is normal, and the information amount in the one pixel becomes the minimum information amount in the one pixel. When you reach If the time required for the repetitive transfer does not reach the receivable allowable time, the untransferred information in one pixel is added and transferred, and the transfer of the print data of the main scanning one line is normal. And the main scanning if the time required for the repetitive transfer reaches the receivable allowable time when the information amount in the one pixel has not reached the minimum information amount in the one pixel. The multi-value data printing method according to claim 1, further comprising: a step of determining that the transfer of the print data of one line is abnormal. 3. A pixel for each main scanning line that transfers the amount of information in one pixel for one main scanning line repeatedly transferred until it is determined that the transfer of the print data is normal. 3. The multivalued data printing method according to claim 2, further comprising a procedure for setting the amount of transferred information in the medium. 4. The multivalued data printing method according to claim 2, further comprising a step of appropriately changing the minimum amount of information in one pixel. 5. In a multi-valued data printing apparatus having no frame memory for printing based on multi-valued print data transferred from a host device, in the information of one pixel of the transferred print data, the degree of importance A multi-valued data printing device characterized in that only information having a large size is transferred for one main scanning line. 6. A means for sequentially repeating the transfer of one line of main scanning from information having a high degree of importance to information having a low degree of information among the information of one pixel, and the time required for this repeated reception. A means for comparing a permissible time that can be received for printing processing of one main scanning line, an information amount in one pixel of the main scanning one line repeatedly received, and a preset minimum information amount in one pixel And the main scanning 1 if the time required for the repeated reception reaches the receivable allowable time when the information amount in the one pixel reaches the minimum information amount in the one pixel. A unit for determining that the print data for the line is normally received, and the time required for the repeated reception when the information amount in the one pixel reaches the minimum information amount in the one pixel Not allowed If it reaches, a means for additionally receiving unreceived information in one pixel to judge that the reception of print data for one main scanning line is normal, and the amount of information in one pixel is 1 Means for determining that the reception of the print data for one main scanning line is abnormal if the time required for the repetitive reception reaches the receivable allowable time when the minimum amount of information in the pixel is not reached. The multivalued data printing device according to claim 5, further comprising: 7. The amount of information in one pixel of one line of main scanning that is repeatedly received by the time it is determined that the print data is normally received, in one pixel of each line of main scanning that is subsequently received. 7. The multi-valued data printing device according to claim 6, further comprising means for setting the received information amount of. 8. The multi-valued data printing apparatus according to claim 6, further comprising means for appropriately changing the minimum amount of information in one pixel.