JP3596221B2 - Image processing device - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an image processing apparatus that converts image data input from a personal computer or the like into bitmap data and outputs the bitmap data to an image forming apparatus, and more particularly, to the size of a page memory included in the image processing apparatus and the output bits. The present invention relates to an image processing apparatus that efficiently outputs bitmap data to an image forming apparatus according to the size of map data.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, an image processing apparatus that converts image data such as a page description language or code data input from a personal computer or the like into bitmap data and outputs the bitmap data to an image forming apparatus includes a bitmap of an image for one page. A method of storing data in a page memory of the image processing apparatus and outputting the bitmap data to the image processing apparatus for each image page (hereinafter referred to as a "frame method") and dividing an image page into a plurality of areas; Then, the bitmap data of the image of the divided one area is stored in the page memory of the image processing apparatus, and the bitmap data is output to the image forming apparatus for each divided area (hereinafter, referred to as “ Band system)).
[0003]
The advantage of the frame method is that the image data is developed into bitmap data each time, and output to the image forming apparatus when the bitmap data for one page of the image is stored in the page memory. Is simple, and the process from receiving the image data by the image processing apparatus to outputting the bitmap data for one page of the image to the image forming apparatus can be performed in a short time. On the other hand, a page memory having a size capable of storing bitmap data for one page of an image is required, and it is economically disadvantageous to require such a large-capacity memory.
[0004]
On the contrary, the band method has an advantage that, since only the bitmap data of the image of the divided one area is stored in the page memory, the size of the page memory is generally smaller than that of the frame method. Sufficient and economically advantageous. On the other hand, the input image data is converted into an intermediate code which is an intermediate data format between the image data and the bitmap data, the one-page intermediate code is stored in the page memory, and furthermore, it corresponds to a specific area. It is necessary to select an intermediate code to be stored and store it in bitmap data, which requires a page memory for storing an intermediate code for one page of an image and complicates the processing. It takes some time from receiving the image data to outputting bitmap data for one page of the image to the image forming apparatus.
[0005]
In the band system, the number of regions into which one page of an image is divided is determined in consideration of the advantages and disadvantages of the band system. That is, the number of divisions can be set to be small when emphasizing the processing speed, and can be set to be large when emphasizing the small page memory size. Further, even when the number of divisions is "1" in the band method, image processing requires more time than in the frame method. This is because, in the case of the band system, even if the number of divisions is "1", it is necessary to convert the image data into an intermediate code once, and further convert it into bitmap data. This is because the management must be divided into an area for storing intermediate codes and an area for storing bitmap data, which complicates processing.
[0006]
In order to make use of the advantages of each of the frame system and the band system, and to compensate for the disadvantages, a technology has been proposed in which the frame system and the band system are switched according to image forming conditions, and the number of divisions in the band system is changed. I have.
[0007]
For example, Japanese Patent Application Laid-Open No. 4-1874 discloses a technique in which a frame method and a band method are switched according to the size of a recording material on which an image is formed, and the number of divisions in the band method is changed. Japanese Patent Application Laid-Open No. 62-35856 describes a technique for changing the number of divisions in a band system according to the size of bitmap data for forming an image.
[0008]
[Problems to be solved by the invention]
However, the size of bitmap data for forming an image is not determined only by the size of the recording material. Also, the size of the page memory of the image processing apparatus is not fixed, and when the memory is expanded or the memory is divided into the system area and the page memory area, the size of the page memory changes due to a change in the system area due to a change in the system design. To do. Therefore, for example, even when the resolution of image formation is set low, the size of the bitmap data is estimated to be larger than the actually required size, so that image processing can be performed by the frame method. Nevertheless, an unnecessary band method may be selected. Further, even when the size of the page memory is increased due to the addition of a memory or the like, an unnecessary band method may be selected because the page memory is not recognized. In these cases, since the mounted memory capacity is not used to the maximum, rapid image processing cannot be performed.
[0009]
SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and aims at not only the size of a recording material on which an image is formed, but also the resolution of an image, whether or not double-sided image formation is performed, and whether or not image formation is defective. The size of the bitmap data of the image to be formed is calculated in consideration of whether or not to re-transfer the image data, whether to compress and hold the bitmap data, and the like. By detecting a change in the size of the page memory due to additional memory, etc., switching between the appropriate frame method and band method even in various situations, and performing image processing with an appropriate number of divisions in the band method, limited It is an object of the present invention to provide an image processing apparatus capable of speeding up processing by maximizing a page memory size.
[0010]
[Means for Solving the Problems]
In order to solve the above problems, the present invention converts a page memory storing bitmap data and / or an intermediate code and image data input from an image input device directly into bitmap data for each page. In an image processing apparatus having first conversion means for storing in the page memory and output means for outputting the bitmap data to an image forming apparatus, one page of image data is converted into an intermediate code and stored in the page memory A second converting means for converting the stored intermediate code for one page of image into bitmap data for each one of a plurality of pages and storing the bitmap data in a page memory; Detecting means for detecting, calculating means for calculating the memory size of bitmap data for one page of an image, and inputting image data to the first converting means Luke in which the type or provided with a mode selection means for determining in accordance with the size of the bitmap data to the output size of the page memory to the second conversion means. With such a configuration of the image processing apparatus, an appropriate image processing method can be selected by comparing the size of the page memory to be mounted with the memory size required for image formation. .
[0011]
Further, according to the present invention, the size of the page memory and the memory size of the bitmap data for one page of the image are determined by what number of pages the intermediate code is converted by the third conversion means into bitmap data. Also has a number-of-divisions determining means for determining the number of divisions. With this configuration of the image processing apparatus, it is possible to select a more detailed and appropriate image processing method.
[0012]
Further, according to the present invention, when the calculating means calculates the memory size of the bitmap data for one page of the image, the size of the recording material on which the image is formed, the resolution of the image, the gradation of the image, and whether the image is color. Alternatively, whether to perform double-sided image formation and whether to retransmit bitmap data when image formation is defective is also considered. With such a configuration of the image processing apparatus, the memory size required for image formation can be accurately grasped, and as a result, a more detailed and appropriate image processing method can be selected. .
[0013]
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Hereinafter, preferred embodiments of the present invention will be described based on examples shown in the accompanying drawings.
Example
Before describing the configuration of the present invention, an example of a so-called multifunction machine having functions of a digital copying machine, a printer, and a facsimile, to which the present invention can be applied, will be described with reference to FIG. The structure of such a multi-function machine includes an image input terminal (hereinafter, referred to as "IIT") for reading an image and converting the image into an electric signal, and an image processing system (hereinafter, referred to as "IIT") for correcting, converting, and editing the image. An electronic subsystem (hereinafter, referred to as “ESS”) that reads input data from a personal computer or the like and converts the input data into print data in accordance with print designation of a print job (hereinafter, referred to as “ESS”). And an image output terminal (hereinafter referred to as "IOT") for forming an image using xerography based on an electrostatic latent image.
[0014]
The IIT employs a reduction optical system using a halogen lamp 1, a mirror 2, and a lens 3, and has a sensor 4 mounted thereon. The signal read by the sensor is amplified by an analog amplifier and converted to a digital signal by an A / D converter.
[0015]
In the IPS, a digital signal coming from the IIT is subjected to various processes to generate an electric signal matching the characteristics of the IOT.
[0016]
The ESS according to the invention of the present application interprets a page description language and a printer control language input through various interfaces from a network, a serial cable, a parallel cable, a communication line, and the like. A font or the like stored in a memory (ROM) is developed into bitmap data, converted into a video signal via a video interface, and output to the IOT.
[0017]
The IOT converts an electric signal output from the video interface of the ESS into a driver for controlling the lighting of the semiconductor laser and converts it into an optical signal. The laser beam scanning device 6 includes an infrared semiconductor laser, a lens, and a polygon mirror, and scans the photosensitive drum 7 as spot light. The photoconductor drum 7 is charged by the charger 8, and an electrostatic latent image is formed by an optical signal. The latent image is converted into a toner image by the rotary developing device 8 and is transferred onto a recording sheet attracted onto the transfer drum 9. The configuration around these photoconductors is called a printer engine 81.
[0018]
Next, the configuration of the embodiment of the present invention will be described with reference to the block diagram of FIG. ESS is an image processing device according to the present invention. PDL and image data in a printer language are input to the ESS through the serial cable 20 or the parallel cable 21 from the personal computer 11, the workstation 12 through the network 23, and the personal computer or the like through the telephone line 24. Through the serial interface 30, parallel interface 31, network interface 32, and communication line interface 33 of the image processing apparatus.
[0019]
The input image data is converted into bitmap data by various means 51 to 58 stored as a control program in a ROM 50 in the ESS, and stored in a page memory 41 in a RAM 40. The bitmap data stored in the page memory 41 is output from the IOT via the video interface 35 by the output means 59 for each page or for each area (hereinafter referred to as "band") obtained by dividing one page into a plurality of areas. It is stored in the memory 80.
[0020]
FIG. 3 shows a flow of the entire processing of the present embodiment. When image data corresponding to one page of image is input, image processing for one page of image is started (S100). Next, whether the image processing is performed by the frame method or the band method is selected by the mode selecting means 57 (S101). At this time, the information to be judged is the size of the page memory 41 included in the ESS detected by the detecting unit 55 and the memory size of the bitmap data for one image page calculated by the calculating unit 56.
[0021]
When the band method is selected by the mode selecting means 57, the number of bands into which one page of an image is to be divided is determined by the division number determining means 58 (S110). In this case, the judgment is made based on the size of the page memory 41 included in the ESS detected by the detecting unit 55 and the size of the bitmap data required for one page of the image calculated by the calculating unit 56. . Next, the image data for one page is temporarily converted into an intermediate code by the second conversion means 52, and the converted intermediate code corresponding to one page of the image is further stored in the page memory 41 (S111). The stored intermediate code is converted into bitmap data for each band by the third conversion means 53 (S112). The bitmap data converted by the third conversion unit 53 is output to the IOT image memory 80 by the output unit 54 when the bitmap data for one band is stored in the page memory 41 (S114). . The converted data may be compressed by the compression / decompression means 59 and stored in the page memory 41 (S113). In this case, at the time of output, the compressed bitmap data is output by the output unit 54 while being expanded by the compression and expansion unit 59.
[0022]
When the frame method is selected by the mode selecting means 57, the image data corresponding to one page of the image is directly converted into bitmap data by the first converting means 51 (S120). The bitmap data converted by the first conversion unit 51 is stored in the page memory 41 (S120). When the bitmap data for one page is stored in the page memory 41, it is output by the output means 54 to the IOT image memory 80 (S122). The converted data may be compressed by the compression / decompression means 59 and stored in the page memory (S121). In this case, at the time of output, the compressed bitmap data is output by the output unit 54 while being expanded by the compression and expansion unit 59.
[0023]
In this way, the image data input from the personal computer 11 is converted into bitmap data and output to the IOT image memory 80. Hereinafter, each step will be described in detail.
[0024]
In S110, the mode selection performed by the mode selection unit 57 is performed by selecting the size of the page memory 41 included in the ESS detected by the detection unit 55 and the necessary bit map for one page of the image calculated by the calculation unit 56. The determination is made based on the data memory size. Here, most image processing apparatuses diagnose the size of their own memory or a defective area of the memory when the power is turned on. In such an image processing apparatus, this information is directly detected by the page memory 41. In this case, the detection means 55 does not need to be provided, so that the structure of the image processing apparatus does not become complicated, which is economically advantageous. When calculating the size of the bitmap data for one page of the image, the calculating means 56 considers the size of the recording material on which the image is formed, the resolution of the image, the gradation of the image, and whether the image is color. Or whether double-sided image formation is to be performed, and whether to retransmit bitmap data when image formation is defective.
[0025]
FIG. 4 is a flowchart showing the mode selection processing by the mode selection means 57 in S110. First, in step S201, the calculation unit 56 calculates the bitmap data size of one page of an image based on the size, resolution, gradation, and whether or not the image is color. For example, in the case of a recording material having an A4 size, a resolution of 600 SPI (spots per inch), two gradations, and a single color, ｛(210 [cm] /25.4 [inch / cm]) ) × 600 [spot / inch] × (297 [cm] /25.4 [inch / cm × 600 [spot / inch]｝ / 8 [bit / byte]], which is approximately 4.15 Mbytes. (Hereinafter, referred to as "first required size").
[0026]
In S202, it is determined whether or not the image to be subjected to the image processing is the back side of the double-sided image formation. This determination differs depending on the specifications of the IOT. In the case of the IOT in which image formation is performed on the front / back / front / back of the recording material, it is determined that the odd number is the front side and the even number is the back side. . If it is not the back side of the double-sided image formation, the process proceeds to S203, where the mode selection unit 57 compares the size of the page memory 41 detected by the detection unit 55 with the first required size calculated in S201. It is determined whether the size is equal to or more than one required size. When the size of the page memory 41 is equal to or larger than the first required size, the frame method is selected. When the size of the page memory 41 is smaller than the first required size, the band method is selected. In step S202, in the case of backside image processing for double-sided image formation, the process proceeds to step S204. In step S204, the calculating unit 56 calculates the backside bitmap data size (first required size) and the front side compressed bitmap data. (Hereinafter referred to as “second required size”). In S205, the mode selection unit 57 compares the size of the page memory 41 detected by the detection unit 55 with the second required size calculated in S204, and determines whether the page memory 41 is equal to or larger than the second required size. . When the page memory 41 is larger than the second required size, the frame method is selected. When the page memory 41 is smaller than the second required size, the band method is selected. In this manner, the frame system and the band system are selected.
[0027]
The above description has been made of the case of the image processing apparatus of the specification in which the page memory 41 of the image processing apparatus holds the compressed bitmap data of the front surface when forming the two-sided image. May be held in the image memory 80 of the IOT. In this case, the IOT image memory 80 takes over part of the page memory 41 required for the image processing apparatus, so that the frame method is more often selected, and as a result, quick image processing can be performed. FIG. 5 is a flowchart showing the mode selection processing (S110) by the mode selection means 57 when the bitmap data compressed on the front surface during the double-sided image formation is stored in the image memory 80 of the IOT. The same processes as those in FIG. 4 are denoted by the same step numbers, and description thereof is omitted. The difference from the case where compressed bitmap data is stored in the image processing apparatus side (FIG. 4) is to select a frame method or a band method regardless of whether image processing is performed on the backside image formation of double-sided image formation. Is a point. This is because the bitmap data whose surface is compressed is not stored in the page memory 41 of the image processing apparatus.
[0028]
Further, the image processing apparatus according to the present embodiment re-outputs image data to the printer engine 81 of the IOT when image formation is defective. Bitmap data for this is compressed and stored in the image memory 80 of the IOT. Therefore, no area is provided in the page memory 41 of the image processing apparatus. However, a configuration in which the page memory 41 of the image processing apparatus has such compressed bitmap data is also conceivable. In this case, the size obtained by adding the size of the compressed bitmap data for image formation failure to the required size calculated in S201 and S204 is set as a new required size. By comparison, the band method or the frame method may be determined.
[0029]
FIG. 6 schematically shows the mode selection in S203. If the size of the page memory 41 of the ESS is equal to or larger than the first required size, which is the memory size of the bitmap data of one page of the image, the frame method is selected (see FIG. 6A). Conversely, when the page memory 41 size is smaller than the first required size, which is the memory size of the bitmap data of one page of the image, the band method is selected (FIG. 6B). This is because the image processing can be performed in a short time by selecting the frame method as much as possible.
[0030]
In S111, the determination of the number of divisions made by the number-of-divisions determination means 58 is based on the size of the page memory 41 in the ESS detected by the detection means 55 and the necessary bits for one page of the image calculated by the calculation means 56. The memory size of the map data is the same as in the above-described mode selection (S101).
[0031]
FIG. 7 schematically shows the determination of the number of divisions in S111. First, the size of the intermediate code corresponding to one image page (hereinafter, referred to as “intermediate buffer”) is subtracted from the page memory 41 of the ESS. This subtraction (hereinafter referred to as “band buffer”) is a memory size capable of storing bitmap data of one band (see FIG. 6A). Next, it is calculated how many times the memory size of the bitmap data for one page of the image is larger than the band buffer size. As shown in FIG. 6B, when the memory size of the bitmap data for one page of the image is larger than (N-1) times the band buffer size and is equal to or smaller than N times, one page of the image is equal to N pages. Decide to divide into bands. At this time, it is theoretically possible to form an image regardless of the number of divisions as long as the number is N or more, but it is not appropriate to increase the number of divisions because the more the number of divisions, the longer the processing time becomes.
[0032]
In this embodiment, the size of the intermediate buffer is determined in advance so that the intermediate code does not overflow in general text. On the other hand, it is also possible to determine the size of the intermediate buffer according to the size of the intermediate code of the image on which the image is actually formed. In this case, the intermediate code is stored in the page memory 41, and after storing the intermediate code for one page of the image, the remaining page memory 41 becomes the size of the band buffer. The number of divisions is determined from the size of the band buffer and the size of the bitmap data for one page of the image. The area information described later is added to the intermediate code after the number of divisions is determined. By determining the size of the intermediate buffer in this manner, overflow of the intermediate buffer can be prevented, and the page memory 41 can be used efficiently. As a result, rapid image processing can be performed. On the other hand, since the area information is added after storing the intermediate code, the processing becomes complicated.
[0033]
Here, in the present embodiment, a certain area of the page memory 41 is designated and used as an intermediate buffer, a band buffer, and a frame buffer, but each of them may be physically different. However, from the viewpoint of efficiently using the entire memory, it is desirable to specify a physically single memory area and use it for an intermediate buffer or the like. In order to reduce the size of the intermediate buffer, various measures are taken in the second conversion means 52 and the third conversion means 53 described later.
[0034]
In S111, the image data is converted into the intermediate code by the second conversion means 52, and the converted intermediate code corresponding to one page of the image is further stored in the page memory 41 (intermediate buffer). In S112, the intermediate code stored by the third conversion means 53 is converted into bitmap data for each band.
[0035]
From the viewpoint of reducing the capacity of the memory used, the smaller the size of the intermediate buffer, the better. Therefore, when the image data input from the personal computer 11 or the like is PDL, the second conversion means 52, The third conversion means 53 performs the following processing.
[0036]
Here, when the characteristics of the data formats of PDL, bitmap data, and intermediate code are arranged, as shown in FIG. 8, the amount of information is the smallest in PDL, the largest in bitmap data, and the intermediate code is the intermediate code. It is. Therefore, the memory occupancy is the smallest in PDL and the largest in bitmap data. Conversely, the time required for conversion to bitmap data is shorter for the intermediate code than for PDL. In other words, PDL imposes a greater load on the CPU 10 during conversion to bitmap data than intermediate code. Therefore, the level of the intermediate code, the format close to the PDL, or the format close to the bitmap data is determined in consideration of the balance between the size of the page memory 41 (intermediate buffer) and the processing capability of the CPU 10. To decide.
[0037]
FIG. 9 shows an example of the intermediate code. In the image, characters "a", "b", and "c" are displayed as objects. When this is expressed as an intermediate code, it is expressed by a character code, a position of a character, a font type, a font size, and presence or absence of character modification such as italic and bold. These intermediate code elements include elements that are unique to the object (for example, character code and character position) and elements that are common to other objects (font type, font size, whether or not character modification is performed). I do. In the present embodiment, these unique elements (hereinafter referred to as “specific information”) and common elements (hereinafter referred to as “attribute information”) are separated, and redundant attribute information is not stored in the page memory 41 (intermediate buffer). To save the page memory 41.
[0038]
Here, which element of the intermediate code is used as the unique information and which element is used as the attribute information is not absolute. In the control means to be described later, the change of the element of each intermediate code is determined. For convenience, the element of the intermediate code for determining the change is determined in advance. This is because it is empirically recognized that there are elements of the intermediate code that have a small change and elements that have a large change, and the elements of the intermediate code that have a small change are uniform. Is stored in the intermediate buffer as it is, and only the elements of the intermediate code of the type that changes frequently are processed by the control means described above. As a result, the processing by the control means can be reduced, and the burden can be reduced. Therefore, this classification is ideally performed according to the type of the image to be formed.
[0039]
Further, in S112 of FIG. 3, the intermediate code for one page of the image is converted into bitmap data one band at a time. At this time, it is necessary to select only the intermediate code of a specific band.
[0040]
As described above, in order to save the page memory 41 and to select an intermediate code of a specific band, the second conversion unit 52 and the third conversion unit 53 are configured as shown in FIG. . The second conversion unit 52 is a PDL-intermediate code conversion unit 520 that converts PDL into an intermediate code, a separation unit 521 that separates each element of the intermediate code into unique information and attribute information, and an object belonging to any band. Area information adding means 522 for adding area information indicating whether or not the element information of the preceding intermediate code is different from the corresponding element of the intermediate code following the intermediate code. Means 523 and control means 524 for storing the corresponding element of the subsequent intermediate code in the page memory 41 (intermediate buffer) when the intermediate code determining means 523 determines that the element is different from the element of the preceding intermediate code. Become. Further, the third conversion means includes an intermediate code-BMD conversion means 530 for converting the intermediate code into bitmap data, and a specific band from the intermediate code for one page of the image stored in the page memory 41 (intermediate buffer). Selecting means 531 for selecting an intermediate code corresponding to the intermediate code, and when outputting the intermediate code from the page memory 41 (intermediate buffer) to the intermediate code-to-BMD converting means 530, the subsequent intermediate code is restored using the preceding intermediate code. Restoration means 532.
[0041]
The second converter converts the PDL into an intermediate code and stores it in the page memory 41 (S111 in FIG. 3). The third converter converts the intermediate code into bitmap data one band at a time (S112 in FIG. 3). The processing flow will be described with reference to the flowcharts of FIGS.
[0042]
FIG. 11 shows a process in which the PDL for one page of an image is converted into an intermediate code for one page of an image by the second conversion means 52 and stored in the page memory 41. First, in step S300, the image processing apparatus starts receiving PDL for one page of an image from a network interface, a serial interface, a parallel interface, or the like. In S301, the PDL-intermediate code conversion means 520 converts PDL into an intermediate code. In S302, the separation unit 521 separates the intermediate code into unique information and attribute information. If it is attribute information, the process proceeds to step S303. In step S303, the intermediate code determination unit 523 determines whether the attribute has changed compared to the immediately preceding attribute. If the attribute information does not change, the process proceeds to step S303. Proceeding to S302, the next intermediate code is processed, so that the attribute information is not stored in the intermediate buffer. If the attribute information changes in S303, the process proceeds to S305. In S305, the area information adding unit 522 adds valid area information to all bands. If the element of the intermediate code is the unique information in S302, the area information adding unit 522 adds the area information indicating the band to which the object represented by the unique information belongs in S304. When the area information is added in S303, the process proceeds to S306. In S306, the intermediate code is stored in the page memory (intermediate buffer). Thereafter, in S307, it is determined whether the reception of the PDL for one page of the image has been completed. If not completed, the process proceeds to S302, where the processing of the next intermediate code is performed. In step S307, when the reception of the PDL for one page of the image ends, the process ends.
[0043]
FIG. 12 shows that the intermediate code for one page of the image stored in the page memory 41 (intermediate buffer) is converted into bitmap data for each band by the third conversion means, and is stored in the page memory 41 (band buffer). This shows the processing until it is stored. In S400, conversion of the intermediate code for one page stored in the page memory 41 (intermediate buffer) into bitmap data is started. In S110 of FIG. 3, the development of the intermediate code for one band is started according to the number of divisions determined by the number of divisions determining means 58 (S401). In S402, the intermediate code is extracted from the page memory 41 (intermediate buffer). In S403, it is selected whether or not the intermediate code extracted by the selection unit 531 is an intermediate code necessary for conversion of the band. If it is not necessary to convert the band, the process proceeds to S406. If necessary for the conversion of the band, the process proceeds to S404, and the restoring unit 532 restores the attribute information (see S303 in FIG. 11) not stored in the page memory 41 (intermediate buffer), and restores the intermediate code. The restored intermediate code is converted into bitmap data by the intermediate code-BMD conversion means 531 (S405). In S406, it is determined whether the conversion process from the intermediate code of the band to the bitmap data has been completed, and if not completed, the process proceeds to S402. If the conversion has been completed, the process proceeds to S407, and it is determined whether or not the conversion processing of all the bands corresponding to one page of the image has been completed. If not completed, the process proceeds to S401. Ends the process (S408).
[0044]
In the present embodiment, the second conversion means separates the intermediate code into unique information and attribute information and does not store the common attribute of the attribute information in the page memory 41 (intermediate buffer). Although the buffer size is reduced, the procedure of S303 and S306 in FIG. 11 will be described with reference to FIG. 13 based on a simple specific example. In addition, for simplicity, in this specific example, the object belongs to one band, and addition of area information (S305 in FIG. 11) is not considered. Although this specific example considers the case where the object is a character, the situation is the same even when the object is a figure.
[0045]
Here, an example in which a character "abcdef" is image-formed on a recording sheet as shown in FIG. Among the elements of the intermediate code of these objects, the character code and the position of the character are set as unique information, and the type of font, the size of the character, and the presence or absence of character modification are set as attribute information. The attribute information of the character "abcef", which is an object, uses Times-Roman as the font, has a size of 12 pt, and has no character modification. The character "d" uses Elite as the font, has a size of 18 pt, and has There are no modifications. FIG. 13B is an example in which such an image formation command is described in PDL.
[0046]
Such a PDL is converted into an intermediate code by the second conversion means 52 (see S111 in FIG. 3, FIG. 11), but each element of the intermediate code is virtually taken vertically and each character is taken horizontally. Consider a table as shown in FIG. First, focusing on the character “a”, the unique information of the intermediate code includes the character code and the position of the character, and the attribute information includes the font type, the character size, and whether or not the character is modified. After the unique information is sorted by the sorting means 521 (S302 in FIG. 11), the area information is added (S304 in FIG. 11), and is stored in the page memory 41 (intermediate buffer) as it is. As for the attribute information, since there is no target for comparing the change in the attribute information, after the area information is added (S305 in FIG. 11), the attribute information is stored in the intermediate buffer by the control unit 524 (S303 in FIG. 11, FIG. d)).
[0047]
Next, paying attention to the character “b” in FIG. 13C, the font type, the character size, and the character modification of the attribute information are the same as those of the character “a” on the left side and do not change. The judgment means 523 makes a judgment. Then, the control unit 524 does not store the font type, character size, and character modification, which are the attribute information of “b”, in the intermediate buffer. The judgment unit 523 also considers “c” in the same way and compares the font type, font size, and character modification with “a” on the left. The font type, font size, and character modification do not change to "a". Therefore, the font type, character size, and character modification which are the attribute information of “c” are not stored in the intermediate buffer 41 (see FIG. 13D).
[0048]
Focusing on the character “d” in FIG. 13C, the font type and the character size of the attribute information are different from those of the character “a” on the left, and the character “d” on the left is It is determined by the determination means 523 that they are common to those of “a”. Therefore, in the page memory 41 (intermediate buffer), only the font type and the character size of the attribute information are stored by the control means 524, and the character modification is not stored. Similarly, if attention is paid to the character “e” in FIG. 13C, the font type and the character size of the attribute information are different from those of the character “d” on the left, and the modification of the character is The determination unit 523 determines that the character is common to the character “a”. Therefore, in the page memory 41 (intermediate buffer), of the attribute information, only the font type and character size are stored by the control unit 524, and character modification is not stored.
[0049]
Focusing on the character "f" in FIG. 13C, the font type and character size of the attribute information are common to those of the character "e" on the left, and the character "f" on the left is used for character modification. It is determined by the determination means 523 that they are common to those of “a”. Therefore, as in “intermediate code of e” in FIG. 13D, the control unit 524 does not store the font type, character size, and character modification that are the attribute information.
[0050]
As described above, the intermediate code is stored in the page memory 41 (intermediate buffer) by eliminating redundant common attribute information. However, since the ESS needs to be finally converted into bitmap data, Must be completely restored. The procedure from the state where the common attribute information is excluded to the point where the intermediate code is completely restored includes adding the area information (S304 and S305 in FIG. 11), selecting the necessary intermediate code (S403 in FIG. 12), The above specific example will be described separately for code restoration (S404 in FIG. 12).
[0051]
In the present embodiment, the correspondence between the intermediate code and the specific band is determined by adding the area information indicating the band to which the object belongs to the unique information and the attribute information of the intermediate code by the area information adding unit 522. Things. Hereinafter, what the area information is, how to add it to the intermediate code (S304 and S305 in FIG. 11), and how to select the intermediate code of an object belonging only to a specific band ( Step S403 in FIG. 12 will be described.
[0052]
FIG. 14 shows an example of the area information. Each of the eight bits indicates each band divided into eight corresponding bands. That is, from the lower bits, the first bit corresponds to the first band, the second bit corresponds to the second band (the same applies hereinafter), the bit in which the object exists is “1”, and the non-existent bit is “0”. Thus, the area where the object exists is shown. More specifically, since the object “a” exists over the first, second, and third bands, the first bit, the second bit, and the third bit of the area information of “a” "1" and the other bits are "0". That is, the area information is “11100000”. Similarly, the fifth bit of “b” is “1”, the other bits are “0”, that is, the area information is “00001000”, and the “c” is the seventh bit and the eighth bit is “1”. , And the other bits are “0”, that is, “00000011” as the area information.
[0053]
FIG. 15B shows the intermediate code stored in the page memory 41 (intermediate buffer). The objects “a”, “b”, and “d”, which are the objects in FIG. , And the intermediate code for the letter "e" are shown in detail. The intermediate code of each character has a character code and a print position as unique information, and has attribute modification information, a font type, and a character size as attribute information. The attribute information of the characters “a”, “b”, and “c” are all the same, the character modification is “none”, the font type is “Times-Roman”, and the character size is “12 pt”. In the attribute information of the character “d”, the character modification is “none”, the font type is “Elite”, and the character size is “18 pt”. FIG. 15A shows an image in which the intermediate code of FIG. 15B is developed into bitmap data.
[0054]
The area information is added to both the unique information and the attribute information of the intermediate code, and the area information representing the band where the object exists is added to the unique information (S304 in FIG. 11). , Valid area information is added to all bands regardless of which band the object belongs to (S305 in FIG. 11). For example, in FIG. 15A, focusing on the character “a” as an object, the character “a” is added to the unique information because the character “a” belongs to the second band among the images divided into eight bands. The area information is “00000010” representing the second band, and the area information added to the attribute information is “11111111” representing all bands.
[0055]
The reason why the area information added to the attribute information represents all bands in this way is closely related to the restoration of the intermediate code, and will be described in the description of the restoration of the intermediate code.
[0056]
As described above, by adding the area information, the intermediate code belonging to the band to be developed can be quickly selected (S403 in FIG. 12). For example, when the third band is developed, an intermediate code whose third bit of the area information is “1” is selected by the selecting means, so that the intermediate code necessary for the third band can be quickly obtained. You can choose. The arrow pointing to each area information in FIG. 15B indicates a state selected by the selection unit 531.
[0057]
When the intermediate code corresponding to one object is stored in the page memory 41 (intermediate buffer), the redundancy is eliminated by the determination unit 523 and the control unit 524, so that the attribute information alone is insufficient, Not complete intermediate code. Therefore, it is necessary to restore a complete intermediate code based on the preceding attribute information. Hereinafter, how to restore the intermediate code in S404 of FIG. 12 will be described.
[0058]
As a prerequisite, it is assumed that a complete intermediate code includes elements such as presence or absence of character modification, font type, character size, and character code and character position as unique information as attribute information. The intermediate codes are restored by the restoration unit in the order in which they are stored in the intermediate buffer by the control unit. In FIG. 15A, it is assumed that the presence or absence of character modification of the character to be printed, the font type, and the character size are the same except for the character "d" in the third band.
[0059]
First, the elements of the intermediate code are input to the restoration means 532 in the order of being stored in the page memory 41 (intermediate buffer) (from the top in FIG. 15B). Here, since the unique information of the intermediate code is stored in the page memory 41 (intermediate buffer) as it is (see S302 in FIG. 11), there is no need to restore it. What is restored here is the attribute information of the intermediate code. All elements (presence or absence of character modification, font type, character size) of the attribute information of the preceding first intermediate code are stored in the memory as the latest information, and the attribute information of the subsequent second intermediate code is stored in the memory. With respect to an element that does not have it (for example, a character size), the element of the latest information corresponding to the element is set as the element of the attribute information of the second intermediate code, and the restoration of the attribute information of the second intermediate code is completed. The element (for example, font type) of the attribute information of the second intermediate code is updated with the latest information stored in the previous memory, and is used for restoring the attribute information of the subsequent third intermediate code. Can be By repeating this, the attribute information of the intermediate code is restored.
[0060]
This will be described more specifically with reference to FIG. FIG. 16 shows how an intermediate code representing an object belonging to the third band is restored. In the latest information, by restoring the preceding intermediate code, the presence or absence of character modification, the type of font, and the element of character size are updated and held.
[0061]
Since the intermediate code is restored in the order of being stored in the page memory 41 (intermediate buffer) (from the top in FIG. 15B), first, the intermediate code of the character “a” is restored. The elements of the intermediate code of the character “a” stored in the page memory 41 (intermediate buffer) are the character code (a) of the unique information and the position (xa, ya) of the character. The intermediate code of the character "a" is restored by combining each element of the attribute information of the latest information, character modification (none), font (Times-Roman), and character size (12 pt). Further, since the attribute information of the character “a” is not stored in the page memory 41 (intermediate buffer), the latest information is not updated, and character modification (none), font (Times-Roman), character size (12 pt) ) Is held.
[0062]
Next, the intermediate code of the character “b” is restored. Elements of the intermediate code of the character “b” stored in the page memory 41 (intermediate buffer) are the character code (b) of the unique information and the position (xb, yb) of the character. The intermediate code of the character "b" is restored by combining each element of the attribute information of the latest information, that is, the attribute information of character modification (none), font (Times-Roman), and character size (12 pt). Further, since the attribute information of the character “b” is not stored in the page memory 41 (intermediate buffer), the latest information is not updated, and character modification (none), font (Times-Roman), character size (12 pt) ) Is held.
[0063]
Further, the intermediate code of the character “d” is restored. The elements of the intermediate code of the character “d” stored in the page memory 41 (intermediate buffer) include the font type (Elite) of the attribute information, the character size (18 pt), the character code (d) of the unique information, and the character (Xd, yd). Each element of the attribute information of the latest information is compared with attribute information such as character modification (none), font (Times-Roman), and character size (12 pt), and among those elements, the intermediate code of the character "d" The intermediate code of the character "d" is restored by combining an element that does not have an element and an element that has character modification (none). Further, since the attribute information of the character “d” is stored in the page memory 41 (intermediate buffer), the font type (Elite) and the character size (18 pt) which are the attribute information are updated as the latest information. The intermediate code is similarly restored for the character "e".
[0064]
Next, the reason why the area information to be added to the attribute information indicates all bands in this way (“11111111” in the above example) will be described. As described above, in the restoration of the intermediate code, the attribute information of the intermediate code is held and updated as the latest information, and the attribute information not stored in the page memory 41 (intermediate buffer) is restored based on the attribute information. To restore the entire intermediate code. Therefore, the attribute information of the intermediate code needs to be selected regardless of which band the intermediate code belongs to and used for restoring the intermediate code. For example, in one-page image formation, when restoring attribute information of an intermediate code of an object belonging to a specific band, for example, a third band, an object restored before that (not necessarily an object belonging to the third band). This is because the attribute information of the intermediate code is held as the latest information, and the attribute information of the intermediate code of the object belonging to the third band is restored based on the latest information.
[0065]
The merit that the area information added to the attribute information represents all bands is that the intermediate code can be easily restored by a simple method. On the other hand, in order to avoid updating the latest information as much as possible, the area information added to the attribute information indicates the band to which the object belongs (for example, “00000100” in the attribute information of the object belonging to the third band). However, in normal image formation, the type of font, the size of characters, and the like are not frequently changed, so that the latest information is not frequently updated in the first place, and there is little merit. In addition, information such as which band the attribute information has changed has to be scanned in advance and newly stored in the memory, which complicates the means.
[0066]
This is the end of the description of the process of the second conversion unit 52 corresponding to S110 in FIG. 3 and the process of the third conversion unit 53 corresponding to S111 in FIG.
[0067]
In S113 (S121) of FIG. 3, the bitmap data is compressed by the compression / decompression means 59 and stored in the page memory 41 (band memory). In this embodiment, this compression method is performed by run-length compression by adaptive predictive coding. However, the present invention is not limited to this. Depending on the type of image to be processed, such as an image with many characters and an image with many figures, An appropriate compression method may be adopted.
[0068]
In S114 of FIG. 3, when the output means 54 prepares the bitmap data for one band, the bitmap data is output to the image memory 80 of the IOT via the video interface 35. In this way, by outputting the image data to the IOT image memory 80 for each band, the page memory 41 does not overflow.
[0069]
In step S101 of FIG. 3, when the frame method is selected, the process proceeds to step S120, where the image data is directly converted into bitmap data by the first conversion unit 51 and stored in the page memory 41 (frame memory). Here, when it takes time to convert image data into bitmap data such as PDL (see FIG. 8), if the IOT is an electrophotographic image forming apparatus, image defects are generally generated. Tends to occur. This is because, in an electrophotographic image forming apparatus, the photoreceptor is rotated at a constant speed during image formation, and once image formation of one page is started, conversion to bitmap data is in time. This is because the supply of data is interrupted. However, when the image memory 80 is provided on the IOT side as in the present embodiment, the image formation can be started after the bitmap data for one image page is accumulated in the image memory 80. Such an image defect does not occur.
[0070]
In S121 of FIG. 3, the bitmap data is compressed by the compression / decompression means 59, and the conditions and method are the same as those described in S113.
[0071]
In S122 of FIG. 3, when the bitmap data for one page of the image is prepared, the output means 54 outputs the bitmap data to the image memory 80 of the IOT via the video interface 35. In this way, by outputting the image data to the IOT image memory 80 for each page, the page memory 41 does not overflow.
[0072]
In this way, the processing from receiving the image data for one page of the image to outputting the bitmap data is completed (S130 in FIG. 3).
[0073]
FIG. 17 shows what method is selected and the number of band divisions is determined in this embodiment according to various page memory 41 sizes and image forming conditions. (1) to (6) in FIG. 17 indicate the size of the page memory 41, the size of bitmap data for one page of an image, one-sided / two-sided image formation, and transfer of bitmap data to the IOT again when image formation is defective. The image diagram of the page memory 41 shows whether or not (presence or absence of jam recovery), the system to be selected (frame system or band system) and the number of divisions of one image page in the case of the band system. is there.
[0074]
In the case of (1), the size of the page memory 41 is 4 Mbytes, the size of the bitmap data for one page of the image is 4 Mbytes, one-sided image is formed, and no jam recovery is performed. In this case, since the size of the page memory 41 is equal to or larger than the bitmap data of one page of the image (the same) and the single-sided image formation and the jam recovery are not performed, the frame method is selected. Therefore, the entire area of the page memory 41 is used as a frame buffer.
[0075]
In the case of (2), the size of the page memory 41 is 4 Mbytes, the size of the bitmap data for one page of the image is 8 Mbytes, one-sided image is formed, and no jam recovery is performed. In this case, since the size of the page memory 41 is smaller than the bitmap data of one page of the image, the band method is selected. Since an area of 3.2 Mbytes is secured as the size of the intermediate code for one page of the image, 0.8 Mbytes can be used as the band buffer. Therefore, one page (8 Mbytes) of an image is divided into ten bands. In the page memory 41, an area of 3.2 Mbytes is used as an intermediate buffer, and an area of 0.8 Mbytes is used as a band buffer.
[0076]
The case of {circle around (3)} is a case where the back side image processing of the double-sided image formation is performed. The size of the page memory 41 is 8 Mbytes, the size of bitmap data for one page of an image is 4 Mbytes, and no jam recovery is performed. In this case, the size of the page memory 41 is compared with the sum of the compressed size of the front side bitmap data, 2 Mbytes, and the size of the rear side bitmap data, 4 Mbytes. Since it is equal to or greater than the sum (large), the frame method is selected. Therefore, the page memory 41 is used as a front frame buffer in which a 2 Mbyte area is compressed, and as a 6 Mbyte area as a back frame buffer.
[0077]
The case of {circle around (4)} is a case where the back side image processing of the double-sided image formation is performed. The size of the page memory 41 is 8 Mbytes, the size of bitmap data for one page of an image is 8 Mbytes, and no jam recovery is performed. In this case, the size of the page memory 41 is compared with the size obtained by adding the size of the bitmap data on the front surface, 4 Mbytes, and the size of the bitmap data on the back surface, 8 Mbytes, and the size of the page memory 41 is determined. Since it is less than the sum, the band method is selected. Since an area of 3.2 Mbytes is secured as the size of the intermediate code for one page of the image on the back side, 0.8 Mbytes can be used as the band buffer. Therefore, one page (8 Mbytes) of the image on the back side is divided into ten bands. Accordingly, in the page memory 41, the area of 2 Mbytes is used as the front frame buffer, the area of 3.2 Mbytes is used as the intermediate buffer on the back, and the area of 0.8 Mbytes is used as the band buffer on the back.
[0078]
In the case of (5), the size of the page memory 41 is 4 Mbytes, the size of bitmap data for one page of the image is 4 Mbytes, one-sided image is formed, and jam recovery is performed. In this case, since the size of the page memory 41 is equal to or larger than the bitmap data of one page of the image (the same) and the single-sided image formation and the jam recovery are not performed, the frame method is selected. Therefore, the entire area of the page memory 41 is used as a frame buffer. In this embodiment, since the bitmap data of the image for the jam recovery is held in the IOT image memory 80, the page memory configuration is the same as that of (1).
[0079]
In the case of (6), the size of the page memory 41 is 4 Mbytes, the size of the bitmap data for one page of the image is 8 Mbytes, one-sided image is formed, and jam recovery is performed. In this case, since the size of the page memory 41 is smaller than the bitmap data of one page of the image, the band method is selected. Since an area of 3.2 Mbytes is secured as the size of the intermediate code for one page of the image, 0.8 Mbytes can be used as the band buffer. Therefore, one page (8 Mbytes) of an image is divided into ten bands. In the page memory 41, an area of 3.2 Mbytes is used as an intermediate buffer, and an area of 0.8 Mbytes is used as a band buffer. In this embodiment, since the bitmap data of the image for the jam recovery is held in the IOT image memory 80, the page memory configuration is the same as that of (1).
[0080]
【The invention's effect】
As described above in detail, according to the present invention, the size of the page memory 41 to be mounted is compared with the memory size required for performing image formation, and the Since the system and the band system can be appropriately selected, quick image processing can be performed.
[0081]
Further, according to the present invention, when the band method is selected, the appropriate number of divisions can be determined by comparing the size of the page memory 41 to be mounted with the memory size required for image formation. In addition, more rapid image processing can be performed.
[0082]
Further, according to the present invention, when calculating the memory size required to form an image, the size of the recording material for forming the image, the resolution of the image, the gradation of the image, whether the image is color, Comprehensively consider whether or not to form double-sided images and whether or not to retransmit bitmap data in the event of poor image formation, so that the required memory size can be accurately grasped, and as a result more fine-grained and appropriate By selecting an appropriate image processing method and determining the number of band divisions, more rapid image processing becomes possible.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of a multifunction peripheral to which the present invention can be applied.
FIG. 2 is a block diagram showing a configuration of a multifunction peripheral to which the present invention can be applied.
FIG. 3 is a flowchart showing a period from the start to the end of image processing for one page of an image using a flowchart.
FIG. 4 is a flowchart illustrating selection of whether to perform image processing by a frame method or a band method.
FIG. 5 is a flowchart showing a selection of whether to use a frame method or a band method in an image processing apparatus that compresses and holds bitmap data in an IOT image memory.
FIG. 6 shows how a frame system and a band system are selected from the size of the page memory 41 and the required memory size.
FIG. 7 shows a case where a band method is selected and how the number of divisions is determined.
FIG. 8 shows the relationship between PDL, intermediate code, and bitmap data.
FIG. 9 is an example of a character which is an object and a character represented by an intermediate code.
FIG. 10 is a diagram for explaining a second conversion unit and a third conversion unit in more detail;
FIG. 11 is a flowchart showing processing from the start of reception of image data of one page to the storage of one-page intermediate code in the page memory 41 (intermediate buffer).
FIG. 12 is a flowchart illustrating a process from the start of conversion of the intermediate code for one page to bitmap data to the end of the conversion using a flowchart.
FIG. 13 shows how one page of image data is stored as an intermediate code in the page memory 41 (intermediate buffer).
FIG. 14 shows area information.
FIG. 15 illustrates a state of the page memory 41 (intermediate buffer) in the first embodiment.
FIG. 16 shows how an intermediate code is restored.
FIG. 17 shows what method is selected and the number of divisions is determined according to the state of image formation.
[Explanation of symbols]
41 page memory, 51 first conversion means, 52 second conversion means, 53 third conversion means, 54 output means, 55 detection means, 56 calculation means, 57 mode selection means, 58: division number determining means, 59: compression / expansion means

Claims (5)

A page memory for storing bitmap data and / or intermediate codes, and first conversion means for directly converting image data input from an image input device into bitmap data for each page and storing the bitmap data in the page memory. An image processing apparatus having output means for outputting the bitmap data to an image forming apparatus,
Second conversion means for converting one page of image data into an intermediate code and storing it in a page memory;
Third conversion means for converting the intermediate code for one page of the image stored in the page memory into bitmap data for a plurality of pages and storing the bitmap data in the page memory
Detecting means for detecting the size of the page memory;
Calculating means for calculating a memory size of bitmap data for one page of an image;
A mode for determining whether to input image data to the first converter or the second converter according to the size of the page memory and the memory size of the bitmap data for one page of the image. An image processing apparatus comprising a selection unit. The number of pages by which the third conversion unit converts the intermediate code into bitmap data is determined according to the size of the page memory and the memory size of the bitmap data for one page of the image. The image processing apparatus according to claim 1, further comprising a division number determination unit. It is desirable to have compression / expansion means for compressing and holding the bitmap data stored in the page memory and for expanding the compressed bitmap data when outputting the bitmap data to the image forming apparatus by the output means. The image processing device according to claim 1 or 2, wherein 4. The image processing apparatus according to claim 3, wherein the calculating unit considers whether or not compression is performed when calculating the memory size of bitmap data for one page of the image. When the calculating means calculates the memory size of the bitmap data for one page of the image, in addition to the size of the recording material, the resolution of the image, whether to form an image on one side or both sides of the recording material, One or more of whether or not to re-output the bitmap data of the image that could not be formed when an image formation failure occurs to the image forming apparatus. The image processing apparatus according to claim 1, wherein:

Images