JP4010386B2 - Image forming apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to image processing in an image forming apparatus such as a plotter or a printer.
[0002]
[Prior art]
In a so-called raster printer, a memory for raster image data of about 4 Mbytes is required for one A4 size page at a resolution of 600 dpi. If this becomes A0 size in a plotter that can handle large-format printing paper, a raster image data memory of about 64 Mbytes, which is 16 times larger, is required. For color printing, a raster image data memory of about 256 Mbytes, which is four times as much, is required. This method is generally called a full bit map method.
[0003]
As another conventional technique, in an ink jet printer and plotter, there is a banding method in which a head sequentially scans each image portion (band) by scanning a plurality of times. In this method, raster image data is successively developed in a memory having a capacity corresponding to an image portion (band) for one scan of the head. In this case, a frame memory for one page is not required, and a partial frame memory having a capacity determined by the number of nozzles of the head and the width of the band is sufficient. When the resolution is 600 dpi and color and the number of nozzles of the head is 160 nozzles, a frame memory of about 2 Mbytes is sufficient. In the embodiment of the present invention, image processing is performed by this method.
[0004]
In the banding method, in addition to the frame memory, a data storage memory for storing intermediate image data after analysis of vector data and raster image data is required. This intermediate image data is called a DL (display list), and a memory (area) for recording this data is called a DL memory. If all the vector data and raster image data can be stored in the DL memory, no image loss occurs.
[0005]
[Problems to be solved by the invention]
By the way, when using large-sized printing paper with a plotter or the like, printing may be performed with a vertically long image being horizontally long so as not to waste the paper. In such a case, it is necessary to perform a rotation process for rotating the image by 90 °. At that time, if the image is vector data, the coordinate value is only changed, so there is no pressure on the memory. However, in the case of raster image data, a working memory area for the width x height of the raster image data is required. It becomes. If the rotation process is performed while the working memory area is insufficient, there is a problem that the memory becomes insufficient during the rotation process of the raster image data, resulting in an image loss.
[0006]
Conventionally, such a problem has not occurred when the image data to be handled is only vector data. However, in recent years, image data in which raster image data such as a photographic image is mixed with vector data has been handled. This problem has become apparent.
[0007]
In order to solve such a problem, the present invention eliminates the occurrence of image loss by determining whether or not raster image data can be rotated on the memory capacity from the result of analysis of input data. An object of the present invention is to provide an image forming apparatus having high performance.
[0008]
[Means for Solving the Problems]
An image forming apparatus according to the present invention includes a data analysis unit that analyzes input image data and data that stores analysis result data of the data analysis unit in an image forming apparatus that forms an image based on image data input from the outside. A memory including a storage area; a rotation processing unit that performs a rotation process on the analysis result data; a frame memory unit that develops a print image in a band unit that is a part of an image based on the analysis result data; The image printing including a printing unit for forming an image in band units based on the print image developed in the memory unit, and a working memory capacity necessary for rotation of the image based on the analysis result of the data analysis unit A memory consumption calculating means for obtaining a memory consumption required for the memory, and comparing the obtained memory consumption with a free capacity of the memory. A determination unit that determines whether or not rotation of the image is executable; and a rotation suppression unit that suppresses rotation of the image when the determination unit determines that rotation of the image is not executable. is there.
[0009]
According to the present invention, it is possible to determine whether or not raster image data can be rotated when analyzing input image data. Therefore, useless data (DL described later) is not generated, and loss of processing time when rotation cannot be performed can be prevented. Data loss can also be prevented.
[0010]
The image data includes vector data and raster image data, and the memory consumption calculation means separately obtains a memory consumption based on the vector data and a memory consumption based on the raster image data.
[0011]
For example, for vector data, the memory consumption calculating means obtains pointer data obtained based on a value obtained by accumulating a predetermined amount of vector entity data amount per vector for the number of vectors and the number of bands spanned by each vector. The memory consumption based on the vector data is calculated by the sum of the amount accumulated for the number of vectors.
[0012]
For raster image data, the memory consumption calculation means calculates the sum of the value obtained by accumulating the uncompressed data size of each raster image data and the amount of work data based on the number of lines and the width of the raster image data of the maximum size. The memory consumption based on the raster image data is calculated.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Here, an ink jet image recording apparatus that forms an image of one band by one scan by scanning a head in which a plurality of nozzles are arranged in the paper transport direction in a direction substantially perpendicular to the paper transport direction will be described as an example. .
[0014]
FIG. 1 is a block diagram showing the configuration of the image forming apparatus according to the present embodiment. In FIG. 1, 11 is a CPU for controlling the operation of the entire apparatus, 12 is a RAM used as a work area for the CPU 11 and a temporary data storage area in addition to a frame memory and a DL memory. A ROM 13 stores a program and data for driving the image forming apparatus, and is used by the CPU 11. Reference numeral 14 denotes an interface unit for connecting to an external computer terminal device or the like (not shown), through which plotter description language data such as vector data and vector modification information data is transferred. Reference numeral 15 denotes an LCD display device for performing display for a man-machine interface, and 16 denotes a key operation unit for selecting various settings of the image forming apparatus. Reference numeral 17 denotes a printing unit of the image forming apparatus, and 18 denotes a system bus that connects the CPU 11 and other elements.
[0015]
FIG. 2 shows a schematic processing flow from input data reception to printing in the present embodiment.
[0016]
First, input data (vector data) is received from the outside (S21), and data analysis is performed on the received data according to the format of the plotter description language (S22). Commonly referred to as the interpreter of this data analysis means. After the analysis, the vector data is stored in the RAM 12 as information on the start point, end point, line width, color, etc. of each vector as an intermediate file. The raster image data is compressed and stored in the RAM 12 (S23). These processes are performed until the analysis of the print start data is completed (S24).
[0017]
After receiving the print start command, image rotation permission determination and rotation processing are performed (S25). Details of this step will be described later.
[0018]
Thereafter, a display list (DL) is generated for each band from the RAM 12 stored as an intermediate file until now (S26). The DL generation is to store the band from which band to which band and what kind of image the RAM 12 stores for each band. When DL generation is completed, VRC processing for converting vector data into raster image data based on data stored in DL generation from the first band and decompressing compressed raster image data is performed (S27). In this VRC process, print data suitable for recording is developed in the RAM 12 (frame memory) in FIG. Based on the print data in the frame memory, an actual print operation is executed (S28).
[0019]
FIG. 3 is a flowchart showing a processing example of intermediate file creation (S23), which is one step in the flow of FIG.
[0020]
As a result of the previous data analysis, it is checked whether the given processing target is vector data or raster image data (S231). In the case of vector data, the start point and end point coordinate values of the vector are calculated (S232). The size (memory consumption in the DL) required for registering this vector in the DL is calculated and stored (S233). This registration is to store the substance data of a vector in a band in which a vector first appears. Further, how many bands (number of bands) the vector between the start point and end point spans is calculated (S234). Since the memory for the pointer size indicating the entity is required in addition to the entity data, the memory consumption amount in the DL is calculated and stored based on the number of bands (S235). Then, the start point and end point information is stored in the intermediate file (S236).
[0021]
In the present embodiment, the memory consumption calculation method in S233 requires 14 bytes per vector to register vector entity data in the DL.
[0022]
DL size of vector entity data + = 14 (1)
It becomes. Here, the symbol “+ =” represents an operation of adding (accumulating) the value on the right side to the current value of the variable on the left side of the expression.
[0023]
In the present embodiment, the memory consumption calculation method in S235 requires 4 bytes for the size of one pointer.
[0024]
DL size spanning between bands + = (4 * (number of bands spanning -1)) (2)
[0025]
If the processing target is raster image data in the previous step S231, the data amount at the time of non-compression is added to the raster image data as a result of the data analysis as shown in the following equation (S237).
[0026]
Uncompressed data size required for rotation + = Uncompressed data size (3)
[0027]
Further, the number of lines and the width size of the input raster image data at this time are calculated and stored according to the following equations. This is a working memory capacity necessary for the rotation processing of the raster image data.
[0028]
Copy area size required for rotation = Number of lines x Width (4)
[0029]
If there are a plurality of raster images in one page of the print target image, the copy area size required for rotation is the maximum area.
[0030]
Thereafter, the raster image data is compressed by a compression process using a well-known method such as pack bits (S239) and stored in an intermediate file (S236).
[0031]
FIG. 4 is a flowchart showing details of the “rotation availability determination & rotation” process which is one step shown in the flow of FIG.
[0032]
In determining whether rotation is possible, first, the previously registered intermediate file is read (S251). Therefore, it is checked whether there is a rotation request (S252). If there is no rotation request, this process is terminated.
[0033]
If there is a rotation request, the memory capacity required at the time of rotation is calculated (S253). The memory capacity required when rotating the raster image data is the sum of the expressions (1), (2), (3), and (4). This total is compared with the remaining memory capacity (S254). If there is free memory capacity, it is possible to rotate the raster image data without losing data, so the rotation process is performed (S255).
[0034]
If there is no free memory capacity, it can be recognized by this determination that data loss will occur anyway even after rotation. In this case, the process proceeds to DL generation (S26) without performing the rotation process. However, a message indicating that rotation is not performed due to insufficient free memory capacity may be output to the user by character display, indicator lamp lighting, or the like (S256).
[0035]
FIG. 5 is a diagram for explaining a state in which actual vector data in the present embodiment is analyzed and DL expansion is performed. In this example, vector 1 and vector 2 are image data, vector 1 extends from band 1 to band 3, and vector 2 extends from band 3 to band 7. Therefore, the number of bands of vector 1 is 3, and the number of bands of vector 2 is 5.
[0036]
An example of a DL created for the image data in FIG. 5 is shown in FIG.
[0037]
In this example, since vector 1 first appears in band 1, entity data of vector 1 is registered in band 1 of DL. The number of bytes is 14. Since vector 1 spans bands 2 and 3, a pointer to vector 1 is registered in bands 2 and 3 of DL. The number of bytes is 4 bytes each. Similarly, since vector 3 first appears in band 3, entity data of vector 3 is registered in band 3 of DL. Therefore, the total memory consumption in DL band 3 is 18 bytes. Since vector 2 extends to subsequent band 7, for each of bands 4-7 of DL, 4 bytes of pointer to vector 2 are consumed. Although an extremely simple example has been shown here, the actual image data has a more complicated DL content. However, the basic structure is as shown in FIG.
[0038]
In this embodiment, when the rotation of the raster image is necessary, it is possible to determine whether or not the raster image can be rotated in terms of memory capacity before performing DL generation. Therefore, it is possible to prevent a loss of processing time when it is determined that the rotation cannot be performed without generating unnecessary DL. DL data loss can also be prevented.
[0039]
The preferred embodiment of the present invention has been described above, but various modifications and changes can be made without departing from the spirit of the invention.
[0040]
【The invention's effect】
According to the present invention, in order to solve the problem that printing is not performed due to insufficient memory capacity at the time of raster image data rotation processing, it is determined whether or not raster image data rotation processing is possible at the time of data analysis of input image data. By performing the above, it is possible to provide a highly reliable image forming apparatus that does not cause image defects.
[Brief description of the drawings]
FIG. 1 is a block diagram illustrating a configuration example of an image forming apparatus according to the present invention.
2 is a flowchart showing a processing flow from input data reception to printing in the image forming apparatus of FIG. 1;
3 is a flowchart showing an example of processing of intermediate file creation (S23), which is one step in the flow of FIG.
4 is a flowchart showing details of a “rotation availability determination & rotation” process that is one step shown in the flow of FIG. 2;
FIG. 5 is a diagram for explaining a state in which actual vector data is analyzed and DL expansion is performed in the embodiment of the present invention.
6 is a diagram showing a memory usage state at the time of DL generation in the image example shown in FIG. 5. FIG.
[Explanation of symbols]
11 CPU
12 ... RAM
13 ... ROM
DESCRIPTION OF SYMBOLS 14 ... Interface 15 ... Liquid crystal display device 16 ... Key operation part 17 ... Printing part 18 ... System bus

Claims (1)

In an image forming apparatus for forming an image based on image data including vector data and raster image data input from the outside,
Data analysis means for analyzing input image data;
A memory including a data storage area for storing analysis result data of the data analysis means;
Rotation processing means for performing rotation processing on the analysis result data;
Based on the analysis result data, frame memory means for developing a print image in band units that are part of the image;
Printing means for forming an image in band units based on the print image developed in the frame memory means;
A memory consumption calculating means for determining a memory consumption required for the image printing, including a working memory capacity necessary for the rotation of the image, based on an analysis result of the data analyzing means;
Determining means for comparing the determined memory consumption with the free space of the memory to determine whether or not the rotation of the image can be executed;
And a rotation inhibiting means for inhibiting the rotation of the image when it is determined that the rotation of the image is not executable by said determining means,
The memory consumption calculation means
Separately calculate memory consumption based on vector data and memory consumption based on raster image data,
For vector data, a value obtained by accumulating a predetermined fixed amount of vector entity data per vector for the number of vectors, and a value obtained by accumulating pointer data amounts obtained based on the number of bands spanned by each vector for the number of vectors, To calculate the memory consumption based on the vector data,
For raster image data, the memory consumption based on the raster image data is calculated by adding the accumulated uncompressed data size of each raster image data and the amount of work data based on the number of lines and the width of the raster image data of the maximum size. Calculate quantity
An image forming apparatus.

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