JP2737880B2 - Character processing apparatus and method - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a character processing apparatus and method for generating a font pattern such as a character symbol and performing character processing, and more specifically, for example, a detachable The present invention relates to an improvement in dynamic allocation (arrangement) of a font pattern storage area when an option RAM board is mounted.

2. Description of the Related Art Conventionally, among output devices such as printers, for example, many output devices that output character symbols and the like other than a print printer in a dot pattern (hereinafter, referred to as a font pattern or a pattern such as a character) include: The character code data provided from the host computer or the like is preliminarily expanded by a character generator into a frame buffer memory (image memory for one page) and output.

It is considered that the pattern information such as characters in the character generator can be roughly classified into the following three ways.

: Font in which a pattern such as a character is composed of a simple dot matrix itself (unprocessed) (hereinafter collectively referred to as "dot matrix"): Font stored as a contour, a stroke, or a coordinate point with respect to the origin of the character (Hereinafter collectively referred to as "vector font"): a font formed by processing a dot matrix pattern using some compression technique (for example, run-length encoding) (hereinafter referred to as "compressed font"). .) Of these, the most commonly used output devices are:
It is a "dot matrix font". This is because the pattern itself such as a character is stored in a dot matrix, so that the development into the frame buffer memory can be performed easily and at high speed.

However, as output devices become more sophisticated and higher resolution, rotation and deformation of characters are required, and so-called "vector fonts" have begun to be generally used.
As a measure for increasing the capacity of fonts resulting from higher resolution, "compressed fonts" have come to be used. More recently, even these mixed types have appeared. All of these are referred to as "non-dot matrix" fonts, although "non-dot matrix" fonts have advantages over "dot matrix" fonts, but generally have a frame buffer compared to simple "dot matrix" fonts. There is a disadvantage that it takes a long time to develop a pattern such as a character in a memory.

As a method for solving this, there is a "font cache method". This means that when a "non-dot matrix" font is expanded to a frame buffer memory, it is previously converted to a "dot matrix" font and the pattern is stored and stored, contributing to an improvement in overall processing speed. This method is used in many output devices.
The pattern storage area for this purpose is called a font cache memory, and the area is usually taken in a random access memory (RAM) built in the main unit.

On the other hand, as a way to expand the device itself,
There are many devices that can easily expand the RAM capacity with an option board or the like. This extended RAM board is usually used for general purposes.

[Problem to be Solved by the Invention] Therefore, in this type of conventional model, even if such an extended RAM board is mounted, the font cache memory is fixedly secured as it is, and thus the font cache memory is secured. The size of the cache memory does not actually increase and is not used as a font cache memory. Therefore, if the capacity of the font cache memory becomes insufficient, the data in the existing cache memory is erased. Thus, a new pattern such as a character is stored. Therefore, the meaning of the addition of the extended RAM board is meaningless, at least from the viewpoint of the font cache memory, and causes a reduction in the efficiency of outputting characters and the like as a visible image.

Therefore, an object of the present invention is to propose a character processing apparatus and method that secure high-speed character output by dynamically changing a storage area of a font pattern as needed.

[Means for Solving the Problems] To achieve the above object, a character processing apparatus according to the present invention comprises: a generating means for generating dot-format font data from non-dot-format font data; Storage means including a cache area for storing the obtained dot-format font data; and, in a case where dot-format font data corresponding to a character to be output is stored in the cache area, the stored dot-format font data is stored. When the font data is expanded, and the dot format font data corresponding to the character to be output is not stored in the cache area, the generation unit generates the dot format font data from the non-dot format font data and generates the font data. Expanding means for expanding the expanded dot format font data, and the storage means It characterized by having a setting means for setting the cache areas of different sizes depending on the capacity.

Further, in order to achieve the above object, according to the present invention, dot format font data is generated from non-dot format font data, and the generated font data is stored in a font cache area and corresponds to a character to be output. When dot-format font data is stored in the cache area, the stored dot-format font data is expanded in an expansion area, and dot-format font data corresponding to a character to be output is stored in the cache area. If not, the character processing method for newly generating dot-format font data from the non-dot-format font data, expanding the generated dot-format font data in the expansion area, and performing character processing, comprises: Area capacity including this cache area and the development area It is characterized by being variably set according to the capacity of the storage means.

Embodiment An embodiment suitable for the present invention will be described below in detail with reference to the accompanying drawings. In this embodiment, a "non-dot matrix type" font is used, and in an output device in which the RAM capacity can be increased by an expansion board or the like, the "font cache" area is defined by a predetermined rule in accordance with the expansion of the RAM capacity. It is possible to extend.

FIG. 2 is a sectional view showing an internal configuration of a laser beam printer (hereinafter, also referred to as LBP) according to an embodiment of the present invention. The laser beam printer shown in the figure can register a pattern such as a character and a fixed format (form pattern) from a data source (not shown). In the figure, reference numeral 100 denotes an LBP main body, which converts character information (character code) and the like supplied from an externally connected host computer (201) into a corresponding character pattern, form pattern, and the like, and prints it on a paper sheet as a recording medium. Reference numeral 300 denotes an operation panel on which switches and LED indicators for operation are arranged, and 101 denotes a printer control unit for controlling the entire LBP 100 and analyzing character information supplied from a host computer. . The printer control unit 101 mainly converts character information into a video signal of a corresponding pattern such as a character and outputs the video signal to the laser driver 102. Laser driver 1
02 is a circuit for controlling the driving of the semiconductor laser 103, and switches on / off the laser beam 104 emitted from the semiconductor laser 103 in accordance with the input video signal. The laser beam 104 is swung right and left by a rotary polygon mirror 105 and illuminated on an electrostatic drum 106 to form a latent image of a pattern such as a character on the electrostatic drum 106. This latent image is developed by a developing unit 107 around the electrostatic drum 106 and then transferred to a sheet. Cut sheets are used as the sheets, and the cut sheets are stored in a sheet cassette 108 mounted on the LBP 100, taken into the apparatus by a feed roller 109 and transport rollers 110 and 111, and supplied to an electrostatic drum 106.

FIG. 1 shows a configuration example of a control system of the output device of FIG.
The control system according to the illustrated configuration shows an example in which character code data and control commands sent from a print information source are input and printing is performed by a printing mechanism that prints a document for each page, such as a laser beam printer. ing. Where 20
Reference numeral 1 denotes a host computer as a print information generator that generates character code data and control commands. Reference numeral 202 denotes an input interface unit including a reception interface circuit for receiving character code data and control commands generated from the host computer 201, and reference numeral 203 denotes an input including a RAM for temporarily storing the character code data and control commands. This is a buffer memory.

Reference numeral 204 denotes a character etc. pattern generator which stores a character etc. pattern which is compression-encoded using a run-length technique.
It is composed of a ROM and its control circuit, and has a so-called code converter function for calculating the address of each character pattern from character code data.

205 is a RAM cartridge having a capacity of 1 Mbyte
It comprises a RAM element, its control circuit, and a connector 206 to be mounted on the main unit. The cartridge 205 is attached to the main body device via a socket 212, and is directly connected to the bus of the CPU 208 of the main body printer.

207 stores a pattern obtained by decoding a compression-encoded pattern such as a character into a raw dot matrix pattern;
It is a font cache memory comprising a RAM for storing. By storing the decoded character pattern in the font cache memory, it is not necessary to decode the used character again, and high-speed printing can be performed.

Reference numeral 208 denotes a general-purpose microprocessor for controlling the entire control unit, which includes a ROM 212 and controls the entire control system according to a program stored in the ROM.

Reference numeral 209 denotes a frame buffer for one page comprising a RAM for developing a character or the like pattern once expanded in a font cache memory from a character or the like pattern generator into an appropriate position in accordance with a print position command from a host computer. It is a far memory. 210 is the frame buffer memory 2
An output interface unit for generating a video signal according to the dot pattern information from 09 and interfacing with the page printer print 111, and 211 is an output interface unit 2
A page printer 101 that receives a video signal from 10 and prints image information based on the video signal, and 101 is a CPU board on which the present control mechanism is mounted.

FIGS. 3A to 3C are diagrams for explaining the actual storage method of the "dot matrix font" and the "non-dot matrix font" in the embodiment. FIG. 3A is a diagram visually showing an unprocessed “dot matrix font”. In the figure, a “●” portion of a pattern such as a character is formed in black, and a “•” portion is not formed. It is shown that. The character pattern has a structure of 32 dots width + 32 dots height. In the drawings, etc. are line numbers. It can be seen that storing the characters of FIG. 3A in the form of a "dot matrix pattern" requires 128 bytes of memory.

FIG. 3B shows the contents of the memory when a pattern such as a character visually represented as shown in FIG. 3A is stored in a ROM or a raw “dot matrix pattern” in the ROM.
It is described in hexadecimal notation, and the portion where a black image is formed has corresponding bits "1" and "1", and the portion where no image is formed has a corresponding bit "0". In this embodiment, the pattern of characters and the like stored in the font cache memory 207 is in the form of FIG. 3B. FIG. 3C shows the contents of the memory when stored in the form of a "non-dot matrix pattern" font in hexadecimal notation. In this embodiment, the "compressed font" using the run-length technique is used. It is. This run-length method specifically has the following rules.

: Each code unit is 4 bits.

: A delimiter code "E" (hexadecimal) is provided for each horizontal direction (scan direction) of the font pattern of one character.

: The code "E" means that the bits of the line pattern following the "E" are all "0".

: A scan line having exactly the same contents as the immediately preceding scan line is represented by a code “F”.

: Each code unit (4 bits) in the scan is "0"
(White) and “1” (black) in this order, and this is repeated.

: However, if the length is 13 or more, code "D"
(Hexadecimal) followed by the sum of one code unit (4 bits). That is, only at this time, the length is represented by 8 bits.

For example, in FIG. 3C, the content of the 14th scan "846
4 "(hexadecimal) means" from 0 to 8 "," 0 "is 8 bits," 1 "is 4 bits," 0 "is 6 bits," 1 "is bit, and hereinafter" 0 "" The content of the 24th scan “44D14E” (hexadecimal) is also “0” from the left
Is 4 bits, “1” is 4 bits, “0” is 14 bits (13+
1), "1" expresses image formation with 4 bits, hereinafter "0"". By using the above rules, 3B
It can be seen that the character pattern shown in the figure requires only 39 bytes of memory.

In the present embodiment, the character etc. pattern generator 204 is a "non-dot matrix font" using this technique.

FIGS. 4A to 4C are memory maps for explaining the use state of the memory.

FIG. 4A is a memory map of a memory space when the entire apparatus is viewed from the CPU 208, and illustrates a state in which the entire 16 MB space is allocated to each device (memory). 0 _H to the address to FFFFF _H address is a storing area of the control protocol of the CPU 208, until 1FFFFF _H addresses from 100000 _H address a space assigned to the internal ROM of the character such as pattern generator 204.
2 MB of RAM from address 20000 _{H to} address 3FFFFF _H is allocated to the RAM incorporated in the main unit, and a RAM element is also mounted. The built-in RAM refers to the cartridge 205 in FIG.
Is a memory in the font cache memory 209 and the frame buffer memory 209 in a state where the memory is not mounted.

Furthermore, expansion RAM, 1 up to 4FFFFF _H address from 400000 _H address
MB is allocated, and mounting on expansion RAM board 205
It is 1MB.

FIG. 4B illustrates the allocation of the entire RAM (that is, only the built-in RAM) for the purpose of use in the RAM when the expansion RAM board 205 is not installed. The area used as a font cache is shown in FIG. 25% of the whole, that is, 0.5 MB is secured.

FIG. 4C illustrates the allocation of the entire RAM according to the purpose of use when the 1 MB extended RAM board 205 is mounted. Of the 1 MB on the board 205, 0.25 MB is allocated to font cache and 0.75 MB for work. Therefore, the area used as font cache is the same in that it is 25% of the whole area, but the capacity is
You can see that it has been expanded to 0.75MB. The socket 212 on the main body side is equipped with a switch (not shown) that enters when pushed, and when the cartridge 205 is mounted, the switch is pushed.
Can be determined.

FIG. 5 is a font table developed in the work area of the built-in RAM by the initialization routine of the CPU 208. In this font table, each unit is formed with a fixed length for each code such as a character. The stored information indicates whether a font pattern has already been developed in the font cache memory 209 or not. It consists of bit information and an address field in the cache memory 209 when it is expanded.

FIG. 6 is an overall flowchart showing the control of the CPU 208. Thereafter, the character code data stored in the input buffer memory 202 is converted into character and other pattern data from when the printer unit and the CPU board 101 are turned on according to the flowchart of FIG. The operation of transferring a pattern such as characters to the front memory 209 and printing the pattern by the page printer printing unit 211 will be described.

When power is supplied to the CPU board 101, the CPU 208 immediately ends a predetermined initialization process (not shown) and immediately determines whether or not the RAM cartridge 205 is mounted on the socket 212 in step S1. If fitted, step
Proceed to S2. In step S2, of the 3 Mbytes of the total RAM capacity, each area is initialized so as to conform to the memory layout of FIG. 4C in which the font cache is set to 0.75 MB. Also in this initialization, the bit or the like shown in FIG. 5, which indicates whether or not the font pattern is expanded in the cache memory, is set to "0".

If the RAM cartridge 205 is not mounted, the process proceeds to step S3, where the font cache is set to 0.5 MB in the total RAM capacity of 2 Mbytes, and each area is initialized so as to conform to the memory layout of FIG. 4B. In this initialization,
Bits and the like shown in FIG. 5, which indicate whether or not a font pattern is developed in the cache memory, are set to "0".

Next, proceeding to step S4, the print data sent from the host computer 201 is received from the input buffer memory 203 via the input interface unit. Here, after receiving information for printing one character, that is, the code of the character, the designation of the printing position, the type of font to be printed, and the like, the process proceeds to step S5. In step S5, the code of the character is checked to determine whether it is a form feed code. If it is not a page break code, since it is a character code to be printed, the process proceeds to step S6 to check whether or not the character pattern to be printed is already stored in the font cache memory 207.
This inspection is performed using the inspection bits shown in FIG.

If already stored, go to step S8,
While controlling where in the frame buffer memory an image is to be formed, the corresponding character pattern or the like is transferred from the font cache memory 207 to the frame buffer memory 209.

If it is determined in step S6 that the frame is not stored in the frame buffer, it is necessary to use the cache memory space left in the above-mentioned font cache in step S3 and step S2. The character or pattern to be read is read from the character or pattern generator 204 and expanded in the font cache memory 209. At this time, the inspection bit is set to "1", and the storage position in the font cache memory is also stored. If the free space of the cache memory 209 is already full, F
In the IFO method, this is handled by sequentially deleting characters and other patterns that were previously cast. Further, the processing in step S8 is the same when step S8 is reached after step S7.

After one character pattern or the like has been developed in the frame buffer memory 209 in this manner, the process returns to step S4 to repeat the above-described processing. On the other hand, if it is determined in step S5 that the code is a page break code, the process proceeds to step S9, where a video signal is generated through the output interface unit 40, and a video signal for one page is sent to the page printer printing unit. The printing of one sheet is completed by the above-described electrophotographic process. Further, the process returns to step S4 to obtain the data of the next page, and the above-described processing is repeated to create pages one after another.

As described above, according to the above-described embodiment, in the output device which handles the "non-dot matrix type" font and the RAM capacity can be increased by an expansion board or the like, the "font cache" is used in accordance with the expansion of the RAM capacity. It has become possible to expand the area with a certain rule. For this reason, there is an effect that the entire RAM space is effectively used and the font cache hit rate is improved by increasing the font cache memory corresponding to the addition of the RAM card by the option. Thereby, the throughput of the entire apparatus is improved.

The present invention can be variously modified without departing from the gist thereof.

In the above embodiment, the extension RAM is of a detachable type.
Therefore, the following modified example is proposed. That is, for example, an area for a frame buffer for a plurality of pages or another program is secured in the built-in RAM in the main body. Therefore, such a spare area may be used as a font cache memory.

In the above embodiment, a laser beam printer is used as an output device. However, the present invention can be applied to an image output device such as a CRT instead of such a printer. In the embodiment, a font using a run-length technique is used as a "non-dot matrix type" font. However, other outline fonts for storing so-called outline coordinates, fonts for storing strokes of characters, and Chinese characters are also used. It can be used in a wide range of "non-dot matrix fonts" such as fonts made by synthesizing radicals. In addition, font
Although it is on RAM, it is easy to replace it with another storage medium (such as a hard disk).

In the present embodiment, there is one character generator and a single "non-dot matrix type" font is used, but a character generator having a plurality of character generators may be used.

Further, in this embodiment, the total size of the font cache memory is
Although the ratio in the RAM capacity is fixed at 25%, it is extremely easy to change the ratio by an external operation. It is also meaningful to perform switching according to practical use, such as 25% when a RAM card is not mounted and 20% when a RAM card is mounted.

It goes without saying that the RAM card does not specify any of a board shape, a cartridge shape, and an IC card shape.

[Effects of the Invention] As described above, according to the character processing apparatus and method of the present invention, the capacity of the storage area of the cache area for storing font data is determined according to the capacity of the storage means including the cache area. By making it variable, for example, when the capacity of the storage means is small, the resources of the storage means can be used for the original processing of the character processing device by reducing the cache capacity. Conversely, when the capacity of the storage means is large, Character processing can be accelerated by increasing the cache capacity. That is, efficient use of storage resources is achieved by dynamically changing the capacity of the cache area in accordance with the capacity of the storage means.

[Brief description of the drawings]

FIG. 1 is a sectional view showing the inside of a laser beam printer to which the present invention can be applied, FIG. 2 is a block diagram showing an example of the configuration of a printer control unit 101, and FIGS. 3A to 3C are characters and the like in an embodiment of the present invention. FIG. 4A to FIG. 4C are diagrams showing a memory map for explaining a use state of a memory in the device of the embodiment, and FIG. 5 is a diagram showing a format of a table for managing a font pattern in the device of the embodiment. FIG. 6 is a flowchart showing the control operation of the CPU in the present embodiment. In the figure, 201: host computer, 202: input interface unit, 203: input buffer memory, 204: character pattern generator, 205: RAM cartridge, 208: CPU, 20
9 ... frame buffer memory, 210 ... output interface unit, 211 ... page printer.

Claims (8)

(57) [Claims] 1. A generator for generating dot-format font data from non-dot-format font data; a storage module including a cache area for storing the dot-format font data generated by the generator; When the dot-format font data corresponding to the character to be stored is stored in the cache area, the stored dot-format font data is expanded, and the dot-format font data corresponding to the character to be output is stored in the cache area. If not stored in the area, the generating unit generates dot format font data from the non-dot format font data, and expands the generated dot format font data. Setting means for setting cache areas of different sizes by setting Character processing apparatus according to claim and. 2. The apparatus according to claim 1, wherein said setting means sets a larger cache area when a removable memory is connected than when no removable memory is connected. Character processor. 3. The character processing apparatus according to claim 1, further comprising printing means for performing printing based on dot-format font data expanded by said expansion means. 4. The storage means includes, in addition to the font cache area, a storage area for storing dot format font data developed by the development means, and the setting means sets the capacity of the storage area to 2. The character processing device according to claim 1, wherein said character processing device does not change regardless of a change in capacity of said storage means. 5. A method for generating dot-format font data from non-dot-format font data, storing the generated font data in a font cache area, and storing dot-format font data corresponding to characters to be output in the cache area. If the stored dot-format font data is expanded in the expansion area, and the dot-format font data corresponding to the character to be output is not stored in the cache area,
In a character processing method of newly generating dot-format font data from non-dot-format font data and expanding the generated dot-format font data in the expansion area to perform character processing, the capacity of the cache area is A character processing method characterized by variably setting according to the capacity of a storage unit including the cache area and the development area. 6. A cache area having a larger size than when no removable memory is connected is set when the capacity of the storage means increases due to the connection of the removable memory. The character processing method according to claim 5. 7. The character processing method according to claim 5, wherein printing is performed based on the expanded dot format font data. 8. The capacity of the expansion area is not changed irrespective of a change in the capacity of the storage means.
Character processing method described in.