JP2001138582A - Serial printer and recording medium with program recorded - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a serial printer which can print at a speed higher than conventional ones by promptly processing characters, and a recording medium in which a program for controlling a printer is recorded. SOLUTION: At least either reading characters or writing characters is batch processed for every plurality of bytes, thereby reducing the number of times of data accessing to a character generator and an image buffer to half or less in the prior art. A developing process time can thus be shortened greatly. Since the batch processing is carried out by the number of bytes equal to a greatest common measure of a bus line width of a CPU and a size of characters, the efficient batch processing of a maximum data size is realized.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a serial printer and a recording medium on which a program is recorded. More specifically, the present invention relates to a serial printer and a recording medium on which a program is recorded, which enables faster printing processing than before by rapidly developing a character image into an image buffer memory.

[0002]

2. Description of the Related Art In recent years, OA offices and digital networks have been rapidly developed, and a serial printer capable of forming an image on various image forming media has been required to have a higher speed. I have.

Here, the “serial printer” is a “serial scan type” or “drum scan type” in which a print head (image forming head) scans an image forming medium such as paper to form a print image. Refers to a printer, such as an ink jet printer or an impact dot printer. Hereinafter, among such “serial printers”, an “inkjet printer” that is particularly remarkable in performance improvement and cost reduction will be described as an example.

FIG. 8 is a block diagram showing a schematic configuration of a conventional ink jet printer.

That is, the printer 100 has an interface unit 112, a receiving unit 114, an interpreting unit 116, an image generating unit 118, a character generator 120, an image buffer 122, and a printer engine 124.

The “print data” transmitted from the host device 200 is transmitted to the receiving unit 11 via the interface unit 112.
4 and then sent to the interpretation unit 116. The interpretation unit 116 analyzes the “print data” and extracts “character data” corresponding to a character (character), “bit image data” corresponding to an image, and the like.

[0007] These data are stored in an image generator 118.
Is converted to a “print image”. Here, the “character data” has a character code (for example, an ASCII (ASCII) code or the like) for specifying a type of a character or a symbol, and modification information such as a font.

[0008] When the image generation section 118 receives the “character data”, the corresponding character is read from the character generator 120 based on the character code and the modification information. Then, the image generation unit 11
8 stores the generated print image in the image buffer 122
Expand on top. The developed print image is printed on predetermined paper by the printer engine 124.

[0009]

However, in the conventional printer as shown in FIG. 8, when a print image generated from a character is developed on the image buffer 122,
There is a problem that the processing time is long because processing is performed for each byte.

FIG. 9 is a conceptual diagram showing how characters are developed in an image buffer. That is, the height of the character "A" shown in the figure is 6 bytes. The image generation unit 118 converts the data of the character “A” into
The data is read from the character generator 120 on a byte-by-byte basis and written into the image buffer 122. That is, 1
When developing a byte string, it is necessary to perform data read and write processing six times. For this reason, it takes time to perform data read and write access processing.

In particular, when the serial printer is used for office use in an office or the like, most of the print contents are documents. Therefore, improving the processing speed of character characters is a very important technical issue for a printer as an OA device.

The present invention has been made based on the recognition of such a problem. That is, an object of the present invention is to provide a serial printer capable of performing character character processing quickly and printing at a higher speed than before, and a recording medium storing a program for controlling the printer.

[0013]

In order to achieve the above object, a serial printer according to the present invention is characterized in that an image forming head and an image forming medium repeatedly perform main scanning and sub scanning relative to each other. A character generator for generating a predetermined character, an image buffer for storing a print image, reading the predetermined character from the character generator, and reading the predetermined character for the image buffer. And an image generation unit that executes writing of the character. The image generation unit performs at least one of the reading and the writing for the predetermined character by n (n is a natural number of 2 or more). It is characterized in that it is executed collectively for each byte.

According to the above configuration, the number of times of data access to the character generator and the image buffer can be reduced to less than half of the conventional case, and the development processing time can be greatly reduced.

Here, C which constitutes the image generation unit
When the bus line width of the PU is m bytes, n is
If the value is equal to m / c (c is a natural number of 1 or more), the CPU bus can be equally divided and used efficiently.

Further, when the size of the predetermined character viewed in the writing direction is s bytes,
Is equal to the greatest common divisor of m and s, efficient batch processing of the largest data size can be realized.

Further, when the size of the predetermined character in the writing direction is an even number of bytes, the image generating section determines at least one of the reading and the writing for the predetermined character by two.
If it is executed collectively for each byte, the number of accesses can be reduced most easily and surely, and the expansion processing can be executed quickly.

On the other hand, a recording medium according to the present invention includes a character generator for generating a predetermined character, an image buffer for storing a print image, reading of the predetermined character from the character generator, and reading the predetermined character from the image buffer. An image generating unit for executing writing of a character, wherein the image forming head and the image forming medium form an image on the image forming medium by relatively repeating main scanning and sub scanning. A recording medium that stores a program for controlling a printer, wherein the program causes the image generation unit to perform at least one of the reading and the writing for the predetermined character, n (n:
It is characterized in that it is executed collectively for every (natural number of 2 or more) bytes.

According to the above configuration, the number of times of data access to the character generator and the image buffer can be reduced to less than half of the conventional case, and the development processing time can be greatly reduced.

Here, C which constitutes the image generation unit
When the bus line width of the PU is m bytes, n is
If the value is equal to m / c (c is a natural number of 1 or more), the CPU bus can be equally divided and used efficiently.

When the size of the predetermined character viewed in the writing direction is s bytes, the n
Is equal to the greatest common divisor of m and s, efficient batch processing of the largest data size can be realized.

Further, when the size of the predetermined character viewed in the writing direction is an even number of bytes, the image generation unit informs the image generation unit of at least one of the reading and the writing for the predetermined character.
If the processing is collectively executed for each byte, the number of accesses can be reduced most easily and surely, and the expansion processing can be executed quickly.

Here, the “recording medium” is, for example, a hard disk (HD), a DVD-RAM, a DVD-RO
M, magneto-optical recording medium, flexible disk (FD)
And various memories such as a RAM and a ROM in addition to the ROM and the CD-ROM.

In addition, programs to be recorded on these media may be used as they are, or may be encrypted, modulated, or compressed as necessary, using a wired line such as an intranet or the Internet, It may be distributed via a line.

[0025]

According to the present invention, when a character is developed in an image buffer, data is read and written in units of a plurality of bytes as appropriate.
It is possible to reduce the time required for the expansion process to half or less than the conventional case.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram showing a schematic configuration of the printer according to the present embodiment.

That is, the printer 10 of the present embodiment
It has an interface unit 12, a receiving unit 14, an interpreting unit 16, a developed size control unit 17, an image generating unit 18, a character generator 20, an image buffer 22, and a printer engine 24.

One feature of the printer 10 of the present invention shown in FIG. 1 is that a development size control unit 17 is provided.
The point is to dynamically control the data size at the time of character expansion processing. However, before describing the details, first, the overall configuration of the printer will be briefly described.

The interface unit 12 is a host device 2
In addition to receiving print data relating to characters and images from 00, it has a role of transmitting various status information such as a data request signal to the host device 200.

The receiving unit 14 has a role of temporarily storing data transmitted from the host device 200 as necessary. In the present invention, the receiving unit 14 is not always necessary, and the print data or the like received by the interface unit 12 may be sent to the interpreting unit 16 immediately.

The interpreting unit 16 analyzes the data sent from the host device 200 and converts necessary data to the image generating unit 1.
8 has the role of sending out. For example, the host device 200
"Header" and "Footer" from the data sent from
Is removed, and data relating to the character and the image is extracted and passed to the image generation unit 18.

The image generation unit 18 generates a print image based on the data sent from the interpretation unit 16,
It has a role of developing on the image buffer 22.

For example, when the data sent from the interpreting unit 16 is related to a character, the image generating unit 18 reads out a character having a font and a size corresponding to the character from the character generator 20. Then, the character is transferred to the image buffer 2
2. Expand to the specified vertical and horizontal positions on 2.

The character generator 20 has a role of providing character and symbol data having various fonts and sizes to the image generating unit 18. Specifically, the character generator 20 may be a recording medium such as a ROM (read only memory) in which various characters are stored in advance, or may convert a character having a predetermined font and size as needed. Data generation means for generating and buffering may be used.

The image buffer 22 has a role as a storage unit for buffering a print image, and can be constituted by a RAM (random access memory), for example.

The printer engine 24 has a print head (not shown), a drive system thereof, a paper feed mechanism, and the like. The print image developed in the image buffer 22 is cut out for each "image band" and sequentially printed on a predetermined sheet. .

FIG. 2 is a conceptual diagram showing an “image band”. Here, the “image band” is also referred to as a “band” or a “line”, and corresponds to a striped print portion printed by a single scan of the print head in a serial printer such as an inkjet printer. Here, the scanning direction of the print head is “main scanning direction”,
The feeding direction of the paper as the image forming medium is often referred to as “sub-scanning direction”. That is, one image band is formed by the print head scanning in the “main scanning direction”. Then, the sheet is sent in the “sub-scanning direction”, so that the formation position of the next image band is determined.

In the case of a recent inkjet printer, the height of the image band viewed in the sub-scanning direction, that is, the print width of the print head is often 6 bytes or more. In many cases, the image buffer 22 can store print images of approximately several image bands.

Next, the function of the developed size control unit 17 in the printer 10 of the present invention shown in FIG. 1 will be described with reference to FIGS.

FIG. 3 is a conceptual diagram illustrating how characters are developed in the image buffer 22 of the printer of the present invention.

Conventionally, as shown in the upper part of FIG.
When the data was expanded to 2, processing was performed for each byte.

On the other hand, in the present invention, when the character "A" having a height of 6 bytes is developed in the image buffer 22 as shown in the middle part of FIG. I do. That is, data is read from the character generator 20 in two-byte units and written into the image buffer 22. In this way, the number of data accesses can be halved and the time for reading and writing can be greatly reduced as compared with the conventional example shown in the upper part of FIG.

Of course, only one of data reading and data writing may be performed for each of a plurality of bytes. Also in this case, the processing time can be reduced by reducing the number of accesses as compared with the related art.

The processing for each of a plurality of bytes is appropriately determined by the expansion size control unit 17. For example, when the height of the character sent from the interpretation unit 16 is an even number of bytes, the expanded size control unit 17 detects the height of this character and sends it to the image generation unit 18 every two bytes. Order expansion processing.

In the present invention, the number of bytes that can be batch-deployed depends on the CPU (central pr
It changes according to the bus line width of the occessig unit). That is, the CPU constituting the image generating unit 18 can read data of the bit number corresponding to the number of wirings of the bus line from the character generator 20 and write the data to the image buffer 22. For example, 16-bit CP
In the case of U, that is, when the bus line width of the CPU is 16 bits, batch processing of up to 16 bits, that is, 2 bytes is possible. On the other hand, when a 32-bit CPU is used, batch processing of 4 bytes (= 32 bits) is also possible, and the number of data accesses can be reduced to 1/4. Further, when a 64-bit CPU is used, 6
Batch processing of bytes (= 48 bits) and 8 bytes (= 64 bits) is also possible. Therefore, as shown in the lower part of FIG. 3, it is also possible to collectively read six bytes from the character generator and write them to the image buffer.

In the current CPU, 3 bytes (= 2
(4 bits), it is difficult to collectively handle odd-numbered bytes, but if a CPU that can handle such odd-numbered bytes collectively is provided,
It is also possible to collectively read data of an odd number of bytes such as 3 bytes or 5 bytes and develop the data in an image buffer.

However, when the CPU bus lines are divided and operated, dividing them into equal widths and operating them in parallel may simplify the processing and increase the efficiency in some cases. That is, when the bus line width is m bytes, it is efficient to perform batch processing for every m / c (c is a natural number of 1 or more) bytes. From this viewpoint, for example, in the case of a 32-bit CPU, 2 bytes (= 16 bits) or 4 bytes (= 3 bits)
It is desirable to perform batch processing for each (2 bits).

More specifically, the CPU of the image generation unit 18
Is 16 bits and the height of the character is 8 bytes, it is possible to perform batch expansion every 2 bytes. When the CPU of the image generation unit 18 is 32 bits and the character height is 8 bytes, batch development for every 4 bytes is efficient.

In other words, in the present invention, the number of bytes of the batch processing that can be determined by the expansion size control unit 17 is efficiently set to the "largest common divisor" of the bus line width of the CPU constituting the image generation unit and the size of the character. It is.

On the other hand, when the size of the character is an odd number of bytes, the situation is slightly different.

FIG. 4 is a conceptual diagram showing a case where the size of the character is 3 bytes. In this case, as shown in the upper part of FIG. 4, when reading and writing of data for each byte are performed, when developing a 1-byte string (vertical direction in the figure),
Three data accesses are required.

On the other hand, as shown in the middle part of the figure, it is also possible to process the first two bytes at a time, and then read and write only one byte. This is possible if the CPU constituting the image generating unit 18 is 16 bits. In this case, the number of data accesses is only two. However, it is necessary to judge the number of bytes to be processed and change it appropriately as each access is made. Therefore, extra time may be required for this determination change processing.

That is, when the character size is an odd number of bytes, the expansion is performed for each byte in consideration of the bus line width of the CPU, the time required for data access, and the time required for the judgment change processing. (Upper part in FIG. 4) or whether expansion for a plurality of bytes is also incorporated (middle part in FIG. 4).

On the other hand, if the bus line width of the CPU is 3 bytes (= 24 bits) or more and can handle 3 bytes at a time, as shown in the lower part of FIG. Batch processing is also possible.

Although FIGS. 3 and 4 show a case where a character is turned on the image buffer in the vertical direction, the present invention is not limited to this.

FIG. 5 is a conceptual diagram illustrating a case where a character is developed in the horizontal direction. That is, the upper part of the figure
The conventional one-byte expansion is shown, the middle part shows two-byte expansion according to the present invention, and the lower part shows six-byte expansion according to the present invention. As described above, the characters may be developed in the horizontal direction, that is, in the main scanning direction on the image buffer 22. In this case, the size of the "width" may be checked instead of the "height" of the character, and the number of bytes to be collectively processed may be determined according to the size.

FIG. 6 is a flowchart showing an example of a character expansion process executed by the expansion size control unit 17 and the image generation unit 18 of the printer 10 according to the present invention.

When the interpretation unit 16 extracts a character from the print data, first, in step S11, the developed size control unit 17 detects the size of the character.
Here, as shown in FIG. 3 or FIG. 4, when the print image is developed in the vertical direction (sub-scanning direction), the “size” of the character is viewed in the vertical direction (sub-scanning direction). "Height". As shown in FIG. 5, when a print image is developed in the horizontal direction (main scanning direction), the “size” of the character is set in the horizontal direction (main scanning direction).
It is the "width" seen in the picture.

When the size of the character is extremely large, the image buffer 22 may "run off". In such a case, the image buffer 22
Is first developed, the print is executed to clear the image buffer 22, and then the remaining part of the character is developed in the image buffer 22.

Next, in step S12, the developed size control unit 17
The greatest common divisor n of the bus line width and the character size
To determine. For example, if the CPU is 16 bits and the character size is 4 bytes, n = 2. And
The developed size control unit 17 instructs the image generating unit 18 of the greatest common divisor n.

Here, as described above, when the character “runs out” of the image buffer, n is determined in consideration of the size of the free area of the image buffer instead of the size of the character.

Next, in step S13, the image generator 18 determines a starting position on the image buffer 22 where the character is to be developed.

Next, in step S14, the image generation unit 18 expands the character every n bytes based on the greatest common divisor n received from the expansion size control unit 17. That is, data is read from the character generator 20 every n bytes, and the data is written into the image buffer 22 every n bytes.

When the development of the character is completed, it is determined in step S15 whether or not there is next print data to be developed in the image buffer.

When there is the next print data (step S1)
5: Yes), the process returns to step S11, and the character is expanded.

When there is no next print data (step S1)
5: Yes) ends the development processing.

In FIG. 6, only the character development processing is shown for the sake of simplicity. However, when image data is sent instead of the character, the image development processing is delayed. Executed.

Further, in FIG. 1, the developed size control unit 17 and the image generation unit 18 are shown as separate components, but the present invention is not limited to this. That is, as is clear from the description of the operation illustrated in FIG. 6, these components can be integrated, and the same effect can be obtained even if the function of the developed size control unit 17 is given to the image generation unit 18. Of course you can get it.

Next, a further specific example of the expansion processing will be described.

FIG. 7 shows the C
15 is a flowchart illustrating an example of a development process when a bus width of a PU is 16 bits.

That is, in this case, the number of bytes of data that can be collectively processed by the image generation unit 18 is 2 bytes (= 16 bits). Therefore, first, step S1
At 1A, it is determined whether or not the size of the character is an even-numbered byte. That is, it is checked whether or not the “height” of the character in the case of vertical development and the “width” of the character in the case of horizontal development are even bytes. This determination is performed by the developed size control unit 17.

If the size of the character is an even-numbered byte (step S11A: Yes), step S12A
, The processing size is n = 2. However, even in this case, when the size of the free area of the image buffer 22 is only 1 byte, n = 1.

On the other hand, if the size of the character is not an even number byte (step S11A: No), the process proceeds to step S1.
Proceeding to 2B, the processing size is set to n = 1. These processes are executed by the developed size control unit 17.

Then, the development size control unit 17 instructs the processing size n thus determined to the image generation unit 18, and the image generation unit 18 performs steps S13 to S1.
At 5, the character expansion processing is executed. These steps can be similar to those described above with reference to FIG. 6, and thus detailed description is omitted.

As described above, when the CPU is 16 bits, it is determined whether or not the character size is an even-numbered byte, and the processing size n may be set to 2 or 1 as appropriate. Therefore, the judgment processing of the developed size control unit 17 becomes extremely clear.

The embodiments of the invention have been described with reference to the examples. However, the present invention is not limited to these specific examples.

For example, in each of the above-described specific examples, an ink jet printer has been illustrated. However, the present invention can be similarly applied to various serial printers such as an impact dot printer to obtain the same effects. be able to. Furthermore, the present invention is not limited to a printer-dedicated machine, and may be a multifunction machine having other functions such as a copying machine and a facsimile machine.

In addition, those skilled in the art can make various additions and changes within the scope of the present invention disclosed in this specification.

[0080]

According to the present invention, the number of times of data access to the character generator and the image buffer is reduced to less than half of that of the related art by executing at least one of reading and writing of characters collectively for each of a plurality of bytes. And the development processing time can be greatly reduced.

Further, according to the present invention, the batch processing of a plurality of bytes is executed so as to equally divide the bus line width of the CPU constituting the image generating unit, thereby achieving the CP
U bus can be used efficiently.

According to the present invention, efficient batch processing of the largest data size is realized by executing batch processing with the number of bytes equal to the greatest common divisor of the CPU bus line width and character size. it can.

Further, according to the present invention, when the size of a character is an even number of bytes, the expansion processing is executed collectively every two bytes, so that the number of accesses can be reduced most easily and reliably, and the expansion processing can be performed quickly. Can be performed.

As described above, according to the present invention, the printer can quickly perform the expansion processing. Therefore,
In offices and the like, when used for office work, a large amount of documents can be printed more quickly than before.

Further, according to the present invention, the host computer can be released earlier and the burden can be reduced.

As described in detail above, according to the present invention, it is possible to provide a serial printer capable of performing a printing process more quickly than in the past, and the industrial advantage is great.

[Brief description of the drawings]

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

FIG. 2 is a conceptual diagram illustrating an “image band”.

FIG. 3 is a conceptual diagram exemplifying a state where characters are developed in an image buffer 22 of the printer of the present invention.

FIG. 4 is a conceptual diagram illustrating a case where a character size is 3 bytes.

FIG. 5 is a conceptual diagram illustrating a case where a character is developed in a horizontal direction.

FIG. 6 is a developed size control unit 17 of the printer 10 of the present invention.
9 is a flowchart illustrating an example of a character development process performed by the image generation unit.

FIG. 7 is a flowchart illustrating an example of a development process when a bus width of a CPU constituting the image generation unit 18 is 16 bits.

FIG. 8 is a block diagram illustrating a schematic configuration of a conventional inkjet printer.

FIG. 9 is a conceptual diagram showing how a character is developed in an image buffer.

[Explanation of symbols]

 10, 100 Printer 12, 112 Interface unit 14, 114 Receiving unit 16, 116 Interpretation unit 18, 118 Image generation unit 17 Expansion size control unit 20, 120 Character generator 22, 122 Image buffer 24, 124 Printer engine 200 Host device

Claims (8)

[Claims] 1. A serial printer for forming an image on an image forming medium by relatively repeating main scanning and sub-scanning between an image forming head and an image forming medium, wherein a predetermined character is generated. A character generator, an image buffer for storing a print image, and an image generator for executing reading of the predetermined character from the character generator and writing of the predetermined character to the image buffer. The unit performs at least one of the reading and the writing for the predetermined character collectively for every n (n is a natural number of 2 or more) bytes. 2. The image processing apparatus according to claim 1, wherein n is equal to m / c (c is a natural number of 1 or more) when a bus line width of a CPU constituting the image generating unit is m bytes. Serial printer described. 3. The method according to claim 2, wherein, when the size of the predetermined character in the writing direction is s bytes, n is equal to the greatest common divisor of m and s. Serial printer. 4. When the size of the predetermined character as viewed in the writing direction is an even number of bytes, the image generation unit performs at least one of the reading and the writing for the predetermined character by two bytes. 2. The serial printer according to claim 1, wherein the serial printer is collectively executed every time. 5. A character generator for generating a predetermined character, an image buffer for storing a print image, and reading of the predetermined character from the character generator and writing of the predetermined character to the image buffer. An image generating unit, and stores a program for controlling a serial printer that forms an image on the image forming medium by relatively repeating main scanning and sub-scanning between the image forming head and the image forming medium. The program, the program causes the image generating unit to collectively perform at least one of the reading and the writing for the predetermined character for every n (n is a natural number of 2 or more) bytes. A recording medium characterized by being executed. 6. The apparatus according to claim 5, wherein n is equal to m / c (c is a natural number of 1 or more) when a bus line width of a CPU constituting the image generating unit is m bytes. The recording medium according to the above. 7. The apparatus according to claim 6, wherein when the size of the predetermined character viewed in the writing direction is s bytes, n is equal to the greatest common divisor of m and s. recoding media. 8. When the size of the predetermined character as viewed in the writing direction is an even number of bytes, the image generation unit transmits at least one of the reading and the writing for the predetermined character to two bytes. 6. The recording medium according to claim 5, wherein the recording medium is executed collectively every time.