JPH09258715A - Image forming device and method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make a font object holdable in a divided state and reusable so as to improve processing speed. SOLUTION: At the time of font-cashing a font object generated on the basis of printing data or the like from the outside, dividing processing is applied to the front object exceeding a specified size, and a header part 505' indicating the connection of each object data 506' is added to each object data 506'. A front object of specified size or less is stored as one object data 506. These object data are retrieved as character codes by indexing tables 502, 503, and if the retrieved front object is divided, these divided object data are connected on the basis of information, held in the header part 505', to describe an image.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image processing apparatus for performing drawing processing by using a font object such as a character pattern generated based on drawing data (for example, data designating a character code and a character size). Regarding the method.

[0002]

2. Description of the Related Art Conventionally, in an image processing apparatus such as a printer for outputting characters, a character pattern corresponding to a character code and a character size designated from the outside according to the data processing resolution, coordinate point sequence data (constituting character contours) Outline data), or vector data and the like obtained by processing the outline data (in the present specification, these are collectively referred to as a font object). Then, the generated font object is drawn on the page memory corresponding to the paper surface or the display to perform the character drawing process.

In order to improve the processing speed, a so-called font cache process is performed in which a font object once generated is held in the work memory (RAM) of the image processing apparatus and is reused. There is. That is, when a character output request is made, the work memory is searched, and if a generated font object with the same font and the same character code is found, the drawing time is shortened by referring to this and drawing. To do.

On the other hand, higher quality image output is desired as a user's need for the image processing apparatus, and accordingly, the data processing resolution is increased and the capacity of the work memory necessary for the data processing is also increased.

Therefore, in the conventional image processing apparatus, the generated font object is subjected to compression processing and retained, and decompression processing is performed at the time of drawing to restore the memory used.

[0006]

However, the above-mentioned conventional example has the following problems. That is, in the conventional image processing apparatus, the work memory used by the font scaler (character generation means) that generates a font pattern based on the scalable data and the capacity of the work memory used when performing character modification, clip processing, etc. , There is an upper limit on the size of the font object that can be handled. Therefore, the conventional font scaler does not generate a character pattern for a character of a certain size or more, but processes outline data to generate vector data, and the vector data is processed by a run length or the like in a subsequent drawing process. By converting it into a graphic object, it is possible to draw large size characters with less memory.

As described above, since characters of a certain size or larger are drawn as graphics, even when a print request for the same character type and the same character code is made, the generated font object (vector data) should be referenced. However, the font scaler needed to generate the same vector data again, and the processing speed could not be improved.

Also, due to hardware limitations, etc., there is generally an upper limit on the size of characters that can be compressed, and large-sized characters cannot be compressed, which impedes the reduction of the amount of memory. .

The present invention has been made in view of the above problems, and provides an image processing apparatus and method capable of dividing a font object, retaining it, and reusing it, thereby improving the processing speed. The purpose is to do.

It is another object of the present invention to divide a font object and hold it so that a large character pattern can be cached and the processing speed is improved.

Another object of the present invention is to divide a font object and hold it so that even a character pattern having a large size can be compressed and cached, and the memory capacity can be reduced. Especially.

Still another object of the present invention is to divide a font object according to the appearance frequency of each character to be drawn,
It is possible to determine execution of holding, prevent unnecessary division and holding of a font object, and improve processing efficiency.

[0013]

An image forming apparatus according to the present invention for achieving the above object has the following arrangement.
That is, an image forming apparatus that forms an image based on image forming data, and a generating unit that generates a font object based on the image forming data and a font object generated by the generating unit are divided to generate divided data. Dividing means for obtaining, dividing means obtained by the dividing means, holding means for holding connection information of the divided data for reproducing the font object, and the font object held by the holding means Is requested by the image formation data, the divided data is connected based on the connection information, and a corresponding font object is formed and output.

Further, preferably, further comprising a judging means for judging whether or not the font object generated by the generating means is larger than a predetermined size, and the dividing means and the holding means include the font object for the font object. It is executed when it is determined that the size is larger than the predetermined size. Since the character having a large font size is divided, even if the font size is large, it is possible to retain the caching and the like.

The holding means holds the font object as it is when the judgment means judges that the font object is smaller than the predetermined size. For example, a font object that can be retained for caching, etc. with the same size is retained as it is without being divided, so wasteful division processing is prevented,
Processing efficiency is improved.

Preferably, the dividing unit divides the font object generated by the generating unit into the predetermined size to obtain divided data. For example, the maximum size that the font scaler can handle as a predetermined size,
Alternatively, it is possible to suppress the number of divisions to the necessary minimum by setting the maximum compression size.

Preferably, the measuring means for measuring the appearance frequency of each of the characters image-formed based on the image forming data, and the division for each character based on the appearance frequency measured by the measuring means. Means and control means for controlling the execution of the holding means. A dividing means for font objects that appear less frequently,
This is because processing efficiency can be improved by suppressing the execution of the holding unit.

Further, preferably, the measuring means measures the frequency of appearance of characters to be image-formed based on the data for one page of the image-forming data.

Further, preferably, the measuring means generates a frequency table for registering characters to be image-formed and their appearance frequency information based on the image-forming data.

Further, preferably, the appearance frequency information is:
For each character registered in the frequency table, it is information that distinguishes a character that appears once and a character that appears twice or more. If the number of appearances is one, the font cache is not referenced, and it is possible to prevent such division and retention of font objects. As a result,
It is possible to significantly improve the processing efficiency with a small amount of data (whether the number of appearances is two or more).

Further, preferably, when the font object held by the holding means is requested by the image forming data, the output means draws information for specifying each of the divided data and a drawing position thereof. And a drawing means for carrying out drawing for forming a visible image based on the drawing information stored in the storage means. This is because the divided data obtained by dividing the font object can be treated as one font object, and the application to the conventional image forming apparatus becomes easy.

Preferably, the holding means compresses and stores the divided data, and the output means decompresses the compressed divided data to form a font object. Compressing and holding font objects reduces memory consumption.

Further, preferably, the holding means has a plurality of types of compressing processing that can be executed, performs different compression processing on each of the divided data and holds them, and stores the divided data in the concatenated information. The information indicating the compression processing applied to the above is added, and the output means expands the divided data by applying the expansion processing corresponding to the compression processing indicated by the connection information to form a font object.
Since it is possible to use a plurality of types of compression processing, it is possible to use compression processing suitable for each divided data, and it is possible to enhance the compression effect.

Further, preferably, the predetermined size is a size that allows compression.

Further, preferably, the font object is a character pattern in which a character shape is indicated by turning pixels on and off, or outline data indicating a series of score points constituting a contour of a character, or outline data is processed. It is composed of any of vector data.

Further, preferably, the image forming data is print data inputted from the outside, and the image forming data further comprises a printing means for printing the font object formed by the output means on a recording paper. The present invention can be applied to the printing apparatus.

[0027] Preferably, it further comprises display means for displaying the font object formed by the output means on a display screen. The present invention can be applied to display means.

Further, preferably, there is further provided a forming means for forming an image based on the font object output by the output means, and a visible output means for visually outputting the formed image. Also, preferably, the visible output means is a printer.

[0029]

Preferred embodiments of the present invention will be described below with reference to the accompanying drawings.

[First Embodiment] FIG. 1 is a sectional view showing the arrangement of an image processing apparatus to which the present invention can be applied. In FIG. 1, a case of a laser beam printer (hereinafter, LBP) is shown as an example of the image processing apparatus. The character processing device to which the present invention can be applied is not limited to the LBP, and may be a printer device of another print method. Further, as long as the function of the present invention is executed, it may be a single device or a system in which processing is performed via a network such as a LAN.

In FIG. 1, reference numeral 100 denotes an LBP body, which is character information (font typeface name, character size, character code, etc.) and graphic data (such as a font typeface name) supplied from an externally connected host computer (200 in FIG. 2). Circle, line,
(Rectangles etc.) or macro commands are input and stored, and corresponding character patterns and graphic patterns are created in accordance with the information, and an image is formed on a recording paper as a recording medium.

Reference numeral 112 denotes a switch and an LED for operation.
An operation panel on which a display and the like are arranged, 101 is an LBP
A printer control unit for controlling the entire 100 and analyzing the print data supplied from the host computer. The control unit 101 mainly converts character information into a video signal of a corresponding character pattern and outputs the video signal on the laser driver 102.

The LBP can also register character patterns and form data from a data source (not shown). Similarly, the LBP converts the video data into a video signal and outputs the video signal to the laser driver 102. Laser driver 102
Is a circuit for driving the semiconductor laser 103, and switches on and off the laser light 104 emitted from the semiconductor laser 103 according to the input video signal. The laser 104 is swung in the left-right direction by the rotary polygon mirror 105 and scans the electrostatic drum 106. Thereby, the electrostatic drum 10
An electrostatic latent image of a character pattern is formed on 6. This latent image is developed by the developing unit 107 around the electrostatic drum 106 and then transferred onto the recording paper. A cut sheet is used as the recording sheet, and the cut sheet recording sheet is LBP1.
The paper is stored in a paper cassette 108 that is in close contact with the paper No. 00, is taken into the apparatus by the paper feed roller 109 and the conveyance rollers 110 and 111, and is supplied to the electrostatic drum 106.

FIG. 2 is a block diagram for explaining the internal structure of the control unit 101 of the image processing apparatus shown in FIG.

In FIG. 2, the printer device main body 100 is shown.
Is connected to an external host computer 200 via a predetermined interface 206, and is configured to execute a predetermined print process according to print data from the host computer 200. The print data received from the host computer 200 is received by the reception buffer 2.
It is temporarily stored in 05 as received data.

Reference numeral 201 denotes a CPU, and based on various control programs stored in the ROM 202 which is a read-only memory, the LBP 100 such as comprehensive control of access to various devices connected to the system bus 204.
Performs calculations and controls to realize all control of. Also,
The ROM 202 is used not only as a control program but also as a font ROM 202e composed of dot font data and scalable font data.

The control program in the ROM 202 is for realizing a series of controls according to the flow charts of FIGS. 3, 6, and 7 described later. As the control program, for example, the object generation unit 202a that analyzes the print data stored in the reception buffer 205 and generates a drawing object that is an internal data format, compresses the drawing object generated by the object generation unit 202a, or Compressing / expanding unit 202 for expanding
c, a character generation unit 202f (font scaler) that generates a font object based on the font data stored in the font ROM 202e as part of the drawing unit 202d that draws the drawing object in the page memory 203c and the drawing object generation unit 202a. Further, it is configured by a font cache unit which determines and divides the number of divisions of font objects, holds the divided font objects for one character in association with each other, and searches for a corresponding font object when a character request is made. ing.

A printing unit I / F 207 outputs the drawn image data as a video signal to the printing unit (printer engine) 208. An image is printed on the recording paper 209 based on the video signal received from the printing unit I / F 207.

Reference numeral 203 denotes a RAM which functions as a main memory of the CPU 201, a work memory 203d and the like. RAM
A drawing object storage unit 203a stores a drawing object generated by the drawing object generation unit 202a according to the input print data, a font object storage unit 203b stores a font object managed by the font cache unit 202b,
A page memory 203c that stores image data of one page sentence (or part of a page) created based on a drawing object (ON / O of each bit of image data)
FF corresponds to the video signal output to the laser driver 102), a print environment data storage memory (not shown), NVRAM, or the like. In addition, RAM
203 is configured so that the memory capacity can be expanded by an option RAM connected to an expansion port (not shown). Further, the LBP 100 is supplied with electric power from a power supply unit (not shown).

Next, the operation of the image processing apparatus of this embodiment having the configuration shown in FIGS. 1 and 2 will be described. A program that executes the following operations is stored in the ROM 202.

FIG. 3 is a flow chart for explaining the drawing process of the image processing apparatus according to the first embodiment. In FIG. 3, first, when power is supplied to the LBP100 main body,
In step S301, each object storage unit 203a,
203b and page memory 203c are initialized, and the resolution of the drawing object / font object created in steps S307 and S309 is set.
In the present embodiment, the resolution of the generated image is 600 dpi.
And Further, a print command designated by a unit system such as point size or mm is converted into the number of dots using this value.

Next, in step S302, print data is received from the external host computer 200, the print data is stored in the receive buffer 205, and the receive buffer 2 is received.
The data of a certain size is read from 05. This data is temporarily stored in a part of the work memory 203d.
Then, in step S303, the command interpretation of the data is performed according to a predetermined grammar, and step S30
According to the analysis result of No. 3, the process branches as follows.

If it is determined in step S304 that the data is a paper discharge command, the process proceeds to step S305. In step S305, the drawing unit 202d sets the drawing objects belonging to the current page to the drawing object storage unit 20.
The data is read from 3a and drawn (rasterized) on the page memory 203c. Thereafter, the printing unit I / F 207 transfers the data on the page memory 203c to the printer engine 208 as a video signal. Step S3
When the paper discharge process ends in 05, the process returns to step S302 and waits for data input for the next page.

On the other hand, if it is determined in step S304 that the data is not the paper discharge command, the next step S306.
At, it is determined whether the data is a character print command. If it is not a character print command, the flow advances to step S307 to check whether the data is a drawing command other than characters. When it is determined that the command is a drawing command, the drawing object generation unit 202a generates a drawing object such as a figure (line, circle, polygon, etc.) or image specified by the data (step S308). If the data is print data other than the drawing command, the process proceeds from step S307 to step S309, and processing such as printing position movement and printing environment setting is performed according to the data, and command interpretation for one unit is performed. finish.

On the other hand, if the data is a character print command in step S306, the process proceeds from step S306 to step S310. In step S310, the font cache unit 202b searches the font object storage unit 203b for a corresponding font object based on the font typeface, character size, and character code specified by the data. If the corresponding font object is found, step S3
From 11, the process proceeds to step S319. In step S319, information necessary for drawing processing is acquired from the font object storage unit 203b, command interpretation for one unit is completed, and the process returns to step S302. Note that step S310
Details of steps S319 and S319 will be described later with reference to FIGS.

On the other hand, if the object is not found in S311, the font object is registered in the font object storage unit 203b in the subsequent step S312 and thereafter. First, in step S312, the character generation unit 202a acquires the character size from the font ROM 202e based on the font typeface, character size, and character code specified by the data. And
The font cache unit 202b determines the number of divisions from the character size.

In this embodiment, the maximum size of one divided block is 16 KB (= 16,384 bytes).
And the character pattern is divided only in the height direction (see FIG. 4). Character size w (width) x h
When a character whose (height) is 500 × 600 dots is generated, if the width direction is treated as 32 bit alignment, the character width is INT {(500 + 31) / 32} × 4 = 64 bytes, The height h'is h '= 16384/6
4 = 256 lines, so the number of divisions n = INT
{(600 + 255) / 256} = 3 is obtained. That is,
A character of 500 × 600 dot size will be divided into three. Note that INT {n} indicates an operation that rounds down the fractional part of n.

In the following step S313, the character generator 20
2f (font scaler) reads out a font pattern or outline data from the font ROM 202e to the work memory 203d to generate (scale) a font object. In the present embodiment, it is assumed that a character having a size (for example, 64 KB) that can be accommodated in the work memory usable by the font scaler is generated in the bitmap format, and a character having a size exceeding 64 KB is generated in the vector data format.

After the following step S314, the step S
The font object generated in 313 is stored in the font object storage unit 203b. First, S3
At 14, it is checked whether the division number n is larger than 0 (n is 1
Since the above is true, the first time is always true), and if n = 0, the drawing information is acquired in step S319, the processing of one character is ended, and the process returns to step S302.

If n> 0, it is judged whether or not n is larger than 1 to check whether or not division is necessary (step S).
315). If division is necessary (n> 1), step S3
The process proceeds from step 15 to step S316 to take out a block of 16 KB and perform division processing. Further, step S31
6, the block height hi (i = 1 to n),
Offset value (offy) to the upper left corner of the block from the reference point, which is the reference point for character printing
i) and the like necessary for drawing processing are calculated (the offset value in the width direction is equal to the offset value offx of one character in all blocks).

FIG. 4 shows an example of character pattern division according to this embodiment and an offset value offy for each divided block.
It is a schematic diagram which shows the relationship of i (i = 1-n). In this embodiment, each block height h1 = h2 = 256 dots, h3 =
600- (256 × 2) = 88 dots, offset value o
ffy1 = offy, offy2 = offy + 256, o
It is calculated as ffy3 = offy + 512 dots.
However, offyi has a negative value.

In a succeeding step S317, a memory required for storing each divided object is acquired from the font object storage section 203b, and the object data in the work memory 203d is stored together with various font information. Here, when the division number n is larger than 1, only the corresponding area of the object data (the area obtained by dividing the object font) is stored. If the required memory cannot be acquired, the unnecessary font object is released and then the memory is acquired.

Finally, the division number n is decremented (step S318), and the process returns to step S314 to process the next block. Although not shown, the number of divisions n
Is greater than or equal to 5, it means that the data exceeds 64 KB, and thus is generated in the vector data format as described above.

When the division number n is 1 (that is, when the font object is not divided), step S31
From step 5, the process directly proceeds to step S317, and the entire font object is stored.

FIG. 5 is a schematic diagram showing the contents of the font object and font information management table created in the process of the drawing process shown in the flowchart of FIG. 3, and the link relationship between them. The font information management table is generated in step S310 of FIG.
The details will be described later with reference to FIGS. 6 and 7.

The font object 504 in this embodiment can be searched from the font information management table 501 using the character code as an index. In addition, the character generation unit 20 receives a drawing request from the outside.
2f and the character code given to the font cache unit 202b have a maximum length of 2 bytes, and the corresponding index is the upper byte index 502 of the character code.
And the lower byte index 503 has two levels of depth. Here, in the single-byte type code system, the high-order byte index 502 is composed of only the members of code = 0x00 (or the index depth is stored in the management table and the index depth is made variable). Does not matter).

Font information management table 501 (hereinafter,
The management table 501) indicates, as information for identifying each font, a font typeface name, a stroke weight (not shown), a graphic set showing the allocation of character codes and actual patterns, a point size, and a scalable font. In addition to a flag, a flag (not shown) indicating fixed pitch or proportional pitch, a flag (not shown) indicating vertical writing / horizontal writing, an index ID for searching a font object and the like are stored, and each management table is stored. Is assigned a font ID.

In the example of FIG. 5, the font ID is 1
No. 2 and No. 2 management tables 501 are registered, and a double-byte type font and a font object (character code = 0x2422 and 0x3021) with a division number n = 1 are linked to the management table with font ID = 1. On the other hand, on the other hand, a font object (character code = 0x41) of a single-byte type font and a division number n = 3 is linked to the management table of font ID = 2. Then, for example, the high-order byte index 502 is linked to the management table 501 by the index ID, and 0x24 of the high-order byte index 502 is the low-order byte index 503, and 0x30 is the low-order byte index 50.
7 are linked.

The links of the indexes 502 and 503, the font object 504, and the divided font objects are managed by IDs, and each information is acquired by obtaining an address in RAM from an ID table (not shown). indexID, objID, nextID).

The font object 504 is linked to the lower byte index 503, and the header part 5
05 and object data 506.
The font object 508 is linked to the lower byte index 507. In the header portion 505, font information for each character such as data division number n, character width w, height h, start address of object data, offset value from reference point and pitch information, and decoration information is set. Has been done. If the number of divisions n is larger than 1, as shown in the header section 505 ', in addition to the above information, the ID (nextID) indicating the next division block and the height hi of each division block
The offset value offyi is also stored. Further, the divided object data 506 ′ is stored corresponding to each of the header parts 505 ′.

In FIG. 5, the font object is R
Although only the character patterns generated in the AM 203 are shown, if the font ROM 202e has character pattern data (such as a dot font that is not divided), the font object does not have to exist in the font object storage unit 203b. Absent. In this case, the address to the beginning of the data is set so as to indicate the beginning of the actual pattern in the font ROM 202e.

In FIG. 5, when the index ID is traced by a given character code (for example, 0x2422), it is as follows. That is, from the index ID of the management table 501 to the “index ID” of the ID table
The address obtained by adding 0x24 to the address obtained from the first (the start address of the index 502) (this is 0x24 of the upper byte index table 502).
The index ID is obtained from the address). Furthermore, 0x is added to the address (the start address of the index 503) obtained from the "IndexID" th in the ID table (not shown).
The objID is obtained from the address obtained by adding 22 (this is the address 0x22 of the lower byte index table 503). Take the procedure of obtaining a font object from the ObjID.

As described above, the creation of the management table and the index is performed when the font object is searched (step S310 in FIG. 3). FIG. 6 is a flowchart showing the procedure of the search process in the first embodiment. Further, FIG. 7 is a flowchart showing the unnecessary cache release processing according to the first embodiment.

First, in step S601 of FIG. 6, the management table 501 is searched, and if the cache table does not exist or a management table having an attribute matching the font attribute specified as print data is not found, step S601 is performed. In step S602, a corresponding management table is created. That is, the memory acquisition for the management table 501 is tried (step S602), and if acquired, the font information corresponding to the area is written (step S60).
3). If the memory for the management table 501 cannot be acquired, the process proceeds to step S604, and unnecessary font objects are released (release processing will be described later with reference to FIG. 7).

On the other hand, if the management table 501 having the same attribute as the requested attribute is found, the following steps S605 and S606 are performed.
In, the upper byte index and the lower byte index are searched. That is, step S605
In, the index ID of the management table 501 is checked to see if it is valid (if it is not valid (for example, if it is an invalid value such as -1), the upper byte index is not found, and the process proceeds to step S607. on the other hand,
If the upper byte index is found, the lower byte index is similarly searched (step S60).
6). If each index is not found, the index is created in the same procedure as the management table (steps S607 to S609 and S610 to S612), and the process proceeds to step S312.

On the other hand, if the lower byte index is found in step S606, the subsequent step S311.
Then, the font object (= cache) is searched by using the information for each character (whether or not there is modification). Here, if the font pattern corresponding to the requested character code is found, it is determined that the cache is hit, and as described with reference to FIG. 3, the process proceeds from step S311 to step S319 to acquire drawing information. If the corresponding phone and pattern are not found, step S as described above with reference to FIG.
From 311 the process proceeds to step S312.

Subsequently, referring to FIG. 7, steps S604, S
The cache release processing in S609 and S612 will be described.

First, in step S701, it is checked whether or not there is an unnecessary cache (request size ≦ total size of unnecessary cache). If there is, the cache is released in step S702, and only the memory required in step S703 is released. To earn. On the other hand, if the total amount of releasable cache is less than the requested size, the process proceeds to step S704, an error display is performed, and the processing of one character is interrupted (return to S302 in FIG. 3). Here, the required size is
This is the size for securing the upper byte index and lower byte index. Further, in the present embodiment, the cache is treated as one of drawing objects. Therefore, the judgment "can be released / cannot be released" is made based on whether or not drawing (rendering) is completed.

Although not described in this embodiment, the releasable cache may be classified into some priorities and managed, and the releasing process may be performed for each priority. For example, modifier characters → JIS 2nd level kanji → JIS
First level Kanji → Set a priority like non-Kanji,
The release level is determined by comparing the total size of the unnecessary cache belonging to each priority with the requested size.

Further, in this embodiment, when the memory cannot be acquired, an error is displayed and the processing of one character is interrupted. However, if the drawing object storage unit 203a has enough space, it is not a font object but an image or the like. It may be drawn as a drawing object. That is, the pattern data itself may be created as a drawing object in the drawing object storage unit 203a. Alternatively, the object being generated may be thinned out or rescaled to reduce the data processing resolution, and the processing may be continued using the vacant memory. In this embodiment, the management table 501 and the memories for the indexes 502 and 503 are acquired from the font object storage unit 203b.

Next, the drawing information acquisition procedure in this embodiment will be described with reference to the schematic diagram of FIG. 8 and the flowchart of FIG.

FIG. 8 is a schematic diagram showing the structure of a font object in the first embodiment. In FIG. 8, two cases are shown: a case where the object is not divided (a) and a case where the object is divided (b).

First, the header section 505 stores a common header section 801 for storing information common to all font objects.
Then, it is divided into body parts 805 whose contents and sizes change depending on the number of divisions n. The common header part 801 has a division number of 80.
2. Includes data resolution 803 and object start address 804. When n = 1, the body portion 805 includes a character width w, a height h (806), and an offset 807 from the reference point to the upper left end.

The body portion 805 when n> 1 is
A head flag 808 indicating whether it is the head of the divided block is included, and in the case of the head, wh and offset value (806, 807) of one character as a whole, height h1 and offset offy1 (809) of the head block pattern, The ID 810 of the next division block is included. On the other hand, if the head flag is 0, information for one character (806, 807) is not included.
When the character pattern is rotated or modified (shadow, pseudo italic processing, outline processing, enlargement / reduction, etc.), the information may be stored in the common header section 801 or added to the management table 501. It doesn't matter.

FIG. 9 is a flow chart for explaining the drawing information output procedure (step S319 in FIG. 3) in the first embodiment.

First, in step S901, the drawing unit 202
d obtains the division number n of the font object. At the subsequent step S902 and thereafter, the font cache unit 202
b selects drawing information to be output to the drawing unit 202d according to the division number n. When n = 1, the width w, the height h, the offset values offx and offy, and the start address of the object are obtained from the body portion 801 of the font object (step S903). On the other hand, when n> 1, in steps S904 to S906, for each divided block,
Width w, height hi, and offset values offx, offy
i, get the start address of the object (i = 1 to 1
n).

Each piece of information obtained as described above is stored in the drawing object storage section 203a. And
These drawing objects are drawn in the page memory 203c when the paper discharge command is received. In this way, each object data obtained by dividing the font object can be handled in the same manner as one font object. Therefore, as the drawing process itself, a general drawing process can be applied, and the application of the present invention is facilitated.

As described above, according to the first embodiment, when the size of the font object is limited by the work memory or the like used by the font scaler (character generation unit 202f), the font size exceeding this limit is set. Objects can be divided and managed. That is, the effect of the font cache can be obtained even for large-sized characters and the like, and even if large-sized characters are frequently used, it is possible to prevent a decrease in processing speed.

[Second Embodiment] In the first embodiment,
The case where the pattern size is 64 KB or less in the bitmap format is shown, but the present invention is also applicable to vector data format data. In this case, FIG.
Common header part 801 of the font object shown in
, A data format flag indicating whether it is a bitmap format or a vector format, and the data size (number of bytes) of the divided object data may be added to the body portion 802.

[Third Embodiment] In the first embodiment,
Although the font object is simply divided and held, if each divided block is compressed and held and is expanded at the time of drawing, the memory efficiency of the phone and the cache can be further improved.

In this case, a compression flag indicating whether or not the font object is compressed is added to the common header part 801 of the font object shown in FIG. 8 of the first embodiment, and the compression processing is performed in step S317 of FIG. It is sufficient to store the font object by applying. Further, in the present embodiment, the compression format is arbitrary and may be different for each divided block. However, when a plurality of types of compression formats are used, the compression flag indicates the compression format in addition to the presence / absence of compression. And

[Fourth Embodiment] In the first embodiment,
All characters to be output are divided and held (cache), but for the characters that appear only once in the print data, the overhead required for the cache processing will be added, It is inefficient. Therefore, in the fourth embodiment, by examining the appearance frequency of characters in the print data and determining whether or not to cache each character, it is possible to more efficiently process large characters. .

FIG. 10 is a block diagram showing the internal arrangement of the image processing apparatus according to this embodiment. Here, configurations having the same functions as the configurations described in FIG. 2 of the first embodiment are denoted by the same reference numerals, and description thereof will be omitted. The image processing apparatus according to the third embodiment is a ROM 2 that stores a control program.
02, a frequency investigation unit 20 for checking the appearance frequency of character data
With 2g.

Next, the character processing procedure of the image processing apparatus of the third embodiment having the configuration of FIG. 10 will be described using the flowchart of FIG. FIG. 11 is a flowchart illustrating the drawing process of the image processing apparatus according to the fourth embodiment.

First, when a command is received in step S1100, the command interpretation of the data is performed according to a predetermined grammar in step S1101. Then, it is determined whether the data is a character print command (step S1102).

If it is not a character print command, step S1
The process proceeds to step 103 to check whether the command is a drawing command other than a character, and if it is determined that the command is a drawing command, the drawing object generation unit 202a causes the figure (bitmap, line, circle, Generate drawing objects such as polygons) and image data (step S
1104). If the data is print data other than the drawing command, processing such as print position movement and print environment setting is performed according to the data (step S110).
5) Complete command interpretation for one unit. Thereafter, the processing proceeds to step S1107.

On the other hand, if it is determined in step S1102 that the command is a character print command, the appearance frequency of print data is totaled in the next step S1106. In this embodiment, a frequency table (variable) having a pair of a character code and a frequency flag for counting the number of appearances is created, and if it is the first print instruction (that is, the character indicated by the data is registered in the frequency table). If not, the character code is registered in the frequency table (the frequency flag is 0 at this point). If it is the second print instruction (when the character code is found in the frequency table), the frequency flag of the character code in the frequency table is set to 1.

FIG. 12 is a diagram showing an example of the data structure of the frequency table. As shown in FIG. 12, 1 is included in the frequency table.
An appearance character corresponding to a page character print command and a frequency flag indicating that the appearance count is plural times are registered.

The above processing is repeated until one page of data is checked (step S1107). For example, in step S1107, the above process is repeated until the paper discharge command is detected.

In the following step S1108, the step S
Based on the result of counting the appearance frequency of characters in 1106, it is determined whether to store the font cache in the font object storage unit. That is, if the frequency flag of the frequency table is 0 (meaning that the font object is used only once), it is not stored as a font cache, but after the character is generated, the data format is converted to a bitmap object ( Step S110
9, S1110), and step S1104) of drawing similar to the bitmap drawing process. Then, step S11
Returning to 07, however, since the tabulation for one page is completed at this point, the process directly proceeds to step S1108 and subsequent steps to process the next character print command.

For the character determined to be cached in step S1108 (the character whose frequency flag in the frequency table is 1), the font object is searched for in step S1111 and thereafter, and if it is searched, the drawing information thereof is acquired ( Steps S1112, S1113). On the other hand, in step S1112, the font object storage unit 203b
If the character is not found in, the number of divisions is determined according to the character size, and the font object storage unit 20
2b as a font cache (step S
1114-S1120). When the caching to the font object storage unit 203b is completed, the drawing information is acquired in step S1113. Steps S1111, S1112, S1114 to S1120 above
And S1113 are steps S310 to S318 of FIG.
And the same processing as S319.

When drawing information is acquired in step S1113, it is determined in step S1121 whether acquisition of drawing information for the page is completed. If not completed, a step for performing a process for the next character print command is executed. Proceed to S1108. If it is determined in step S1121 that the processing for the page is finished,
In step S1122, the paper discharge process is executed. That is, the drawing unit 202d reads the drawing object belonging to the current page from the drawing object storage unit 203a and draws (rasterizes) it on the page memory 203c. Thereafter, the printing unit I / F 207 transfers the data on the page memory 203c to the printer engine 208 as a video signal.

As described above, the font cache is not executed for the character that appears only once, but the font cache is executed for the character that appears multiple times. Therefore, useless font cache processing is prevented and processing efficiency is improved.

In the third embodiment, the frequency flag is a flag (1 indicating whether or not each character appears twice or more).
However, the number of appearances may be counted. Then, the font cache may be configured to be executed for a character having the number of appearances greater than or equal to a predetermined number. According to this structure, the appearance frequency of the font cache can be set according to the capacity of the font memory, and the font memory can be effectively used.

As described above, according to each of the above-described embodiments, since a character having a large character size is divided and cached, the processing speed is greatly improved when the same character is output for the second time and thereafter. It is possible to reduce the work memory used.

Furthermore, according to the fourth embodiment, it is possible to select whether to divide / hold (caching) according to the appearance frequency of characters in the data, and the appearance frequency is low (for example, used only once). Font objects (which are not processed) can be processed at high speed without division.

In each of the above-described embodiments, the LBP (laser beam printer) is used as the printing apparatus, but it goes without saying that the present invention can be applied to printing apparatuses of other recording systems such as ink jet printers.

Further, in the above-described embodiment, the example applied to the drawing process in the printing apparatus is shown, but the CRT or LCD
It goes without saying that the present invention can also be applied to drawing processing on a display device such as.

The present invention can be applied to a system including a plurality of devices (for example, a host computer, an interface device, a reader, a printer, etc.), but can be applied to a single device (for example, a copier, a facsimile). Device).

Further, an object of the present invention is to provide a storage medium storing a program code of software for realizing the functions of the above-described embodiments to a system or an apparatus, and to provide a computer (or CPU) of the system or apparatus.
And MPU) read and execute the program code stored in the storage medium.

In this case, the program code itself read from the storage medium implements the functions of the above-described embodiment, and the storage medium storing the program code constitutes the present invention.

As a storage medium for supplying the program code, for example, a floppy disk, hard disk, optical disk, magneto-optical disk, CD-ROM, CD
-R, a magnetic tape, a nonvolatile memory card, a ROM, or the like can be used.

When the computer executes the readout program code, not only the functions of the above-described embodiment are realized, but also the OS (Operating System) running on the computer based on the instruction of the program code. ) May perform some or all of the actual processing, and the processing may realize the functions of the above-described embodiments.

Further, after the program code read from the storage medium is written into a memory provided in a function expansion board inserted into the computer or a function expansion unit connected to the computer, based on the instruction of the program code, It goes without saying that the CPU included in the function expansion board or the function expansion unit performs part or all of the actual processing, and the processing realizes the functions of the above-described embodiments.

When the present invention is applied to the above-mentioned storage medium, the storage medium stores the program code corresponding to the above-mentioned flow chart. Briefly, in the memory map example of FIG. Each module shown will be stored in the storage medium.

That is, at least the program code of each of the “generation processing module”, “division processing module”, “holding processing module” and “output processing module” may be stored in the storage medium. Further, preferably, as shown in FIG. 13, a “measurement processing module” is further added.
And "control processing module".

Here, the generation processing module is a program module that realizes generation processing for generating a font object based on image forming data such as print data. The division processing module is a program module that realizes division processing for dividing the font object generated in the generation processing to obtain division data. The holding processing module is a program module that realizes a holding process of holding the divided data obtained by the dividing process and holding the connection information of the divided data for reproducing the font object. Furthermore, when the font object held in the holding process is requested by the image forming data, the output processing module connects the divided data based on the connection information, forms a corresponding font object, and outputs the font object. It is a program module that realizes output processing.

The above-mentioned measurement processing module is a program module that realizes measurement processing for measuring the appearance frequency of each character formed in an image based on the image formation data. The control processing module is a program module that realizes a control processing for controlling the execution of the division processing and the holding processing for each character based on the appearance frequency measured by the measurement processing.

[0109]

As described above, according to the present invention,
The font object can be divided and held and reused, and the processing speed in the image forming process can be improved.

Further, according to the present invention, by dividing and holding the font object, it becomes possible to cache even a large character pattern, and the processing speed of the image forming processing is improved.

Further, according to the present invention, by dividing and holding a font object, it becomes possible to perform compression processing and caching even for a character pattern having a large size. For example, the memory capacity in the font cache can be reduced. To be achieved.

Furthermore, according to the present invention, it is possible to determine whether to divide or hold a font object according to the appearance frequency of each character to be drawn, and prevent unnecessary division or holding of the font object. It is possible to improve processing efficiency.

[0113]

[Brief description of drawings]

FIG. 1 is a sectional view showing a configuration of an image processing apparatus to which the present invention can be applied.

2 is a block diagram illustrating an internal configuration of a control unit of the image processing apparatus in FIG.

FIG. 3 is a flowchart illustrating a drawing process of the image processing apparatus according to the first embodiment.

FIG. 4 is an example of dividing a character pattern according to the present embodiment,
Offset value offyi (i = 1 to 1) for each divided block
It is a schematic diagram which shows the relationship of n).

FIG. 5 is a schematic diagram showing the contents of a font object and a font information management table, and the link relationship between them.

FIG. 6 is a flowchart illustrating a procedure of search processing according to the first embodiment.

FIG. 7 is a flowchart showing processing of releasing unnecessary cache according to the first embodiment.

FIG. 8 is a schematic diagram showing a configuration of a font object in the first embodiment.

FIG. 9 is a flowchart illustrating an output procedure of drawing information according to the first embodiment.

FIG. 10 is a block diagram showing an internal configuration of the image processing apparatus according to the present embodiment.

FIG. 11 is a flowchart illustrating a drawing process of the image processing apparatus according to the fourth embodiment.

FIG. 12 is a diagram showing a data configuration example of a frequency table.

FIG. 13 is a diagram showing an example of a memory map of a storage medium storing a control program according to the present invention.

[Explanation of symbols]

 100 printer device 101 printer control unit 201 CPU 202 ROM 202a drawing object generation unit 202b font cache management unit 202c compression / decompression unit 202d drawing unit 202e font ROM 202f character generation unit 203 RAM 203a drawing object storage unit 203b font object storage unit 203c page Memory 205 Receive buffer

Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI Technical display location G09G 5/26 630 G06F 15/72 355U

Claims (23)

[Claims] 1. An image forming apparatus for forming an image based on image forming data, comprising: generating means for generating a font object based on the image forming data; and dividing the font object generated by the generating means. Dividing means for obtaining divided data, and holding the divided data obtained by the dividing means,
Holding means for holding connection information of the divided data for reproducing the font object; and, when the font object held by the holding means is requested by the image forming data, the division information based on the connection information. An image forming apparatus comprising: an output unit that connects data, forms a corresponding font object, and outputs the formed font object. 2. The image forming apparatus further comprises: determining means for determining whether or not the font object generated by the generating means is larger than a predetermined size, wherein the dividing means and the holding means have the font object having the predetermined size. The image forming apparatus according to claim 1, wherein the image forming apparatus is executed when it is determined to be larger than the above. 3. The image according to claim 2, wherein the holding unit holds the font object as it is when the determining unit determines that the font object is smaller than the predetermined size. Forming equipment. 4. The image forming apparatus according to claim 2, wherein the dividing unit divides the font object generated by the generating unit into the predetermined size to obtain divided data. 5. A measuring unit that measures the appearance frequency of each of the characters that are image-formed based on the image forming data; and an appearance frequency that is measured by the measuring unit.
The image forming apparatus according to claim 1, further comprising a control unit that controls execution of the dividing unit and the holding unit for each character. 6. The image forming apparatus according to claim 5, wherein the measuring unit measures the appearance frequency of the characters formed on the image based on the data for one page of the image forming data. 7. The image forming apparatus according to claim 5, wherein the measuring unit generates a frequency table for registering characters to be image-formed and appearance frequency information of each character based on the image-forming data. . 8. The appearance frequency information is information that distinguishes, for each character registered in the frequency table, a character that appears once and a character that appears twice or more. The image forming apparatus according to item 1. 9. The output means stores, when the font object held by the holding means is requested by the image forming data, information specifying each of the divided data and a drawing position thereof as drawing information. 9. The image forming apparatus according to claim 1, further comprising a storage unit and a drawing unit that performs drawing for forming a visible image based on the drawing information stored in the storage unit. 10. The storage device compresses and stores the divided data, and the output device decompresses the compressed divided data to form a font object. The image forming apparatus according to any one of 1. 11. The holding unit has a plurality of types of compressing processes that can be executed, performs different compressing processes on each of the divided data to hold them, and applies the concatenated information to each divided data. The information indicating a compression process is added, and the output unit applies a decompression process corresponding to the compression process indicated by the connection information to decompress the divided data to form a font object. The image forming apparatus according to item 10. 12. The image processing apparatus according to claim 2, wherein the predetermined size is a size that allows compression. 13. The font object is a character pattern in which a character shape is indicated by turning pixels on or off, or outline data indicating a series of score points forming a contour of a character, or vector data obtained by processing the outline data. The image forming apparatus according to any one of claims 1 to 12, wherein the image forming apparatus is configured by any one. 14. The image forming data is print data input from the outside, and the image forming data further includes a printing unit that prints a font object formed by the output unit on a recording sheet. The image forming apparatus according to any one of 1. 15. The image forming apparatus according to claim 1, further comprising display means for displaying a font object formed by the output means on a display screen. 16. The image forming apparatus according to claim 1, further comprising a forming unit that forms an image based on a font object output by the output unit, and a visible output unit that visually outputs the formed image. Image forming device. 17. The image forming apparatus according to claim 16, wherein the visible output unit is a printer. 18. An image forming method for forming an image based on image forming data, comprising: a generating step of generating a font object based on the image forming data; and dividing the font object generated in the generating step. A dividing step of obtaining divided data, and holding the divided data obtained in the dividing step,
A holding step of holding connection information of the divided data for reproducing the font object, and the division based on the connection information when the font object held in the holding step is requested by the image forming data. And an output step of connecting data to form a corresponding font object and outputting the font object. 19. A measurement step of measuring the appearance frequency of each of the characters image-formed based on the image formation data, and based on the appearance frequency measured by the measurement step,
The image forming method according to claim 18, further comprising a control step of controlling execution of the dividing step and the holding step for each character. 20. The method according to claim 18, further comprising a forming step of forming an image based on the font object output in the output step, and a visible output step of visually outputting the formed image. Image forming method. 21. The visible output step forms and outputs a visible image by a printer.
2. The image forming method according to 1., 22. A computer-readable memory storing a program code for forming an image based on image forming data, the code of a generating step of generating a font object based on the image forming data; The code of the dividing step for dividing the generated font object to obtain divided data, and holding the divided data obtained in the dividing step,
A code of a holding step for holding the connection information of the divided data for reproducing the font object, and when the font object held in the holding step is requested by the image forming data, based on the connection information. And a code of an output process for connecting the divided data to form a corresponding font object and outputting the font object. 23. Based on a code of a measuring step for measuring the appearance frequency of each character image-formed based on the image forming data, and the appearance frequency measured by the measuring step,
23. The computer-readable memory of claim 22, further comprising a control process code that controls execution of the dividing process and the holding process for each character.