JPH05328110A - Method and device for image forming - Google Patents

Abstract

PURPOSE:To improve the gradation of print by selecting the gradation pattern of plural picture elements corresponding to inputted one-picture element multigradation picture data and performing the varyiable processing of the printed picture element density and converting picture data to an integer multiple resolution of one picture element, thereby substituting the picture data with the gradation pattern. CONSTITUTION:An input data processing part 102 separates only picture data of inputted one-picture element multigradation data Dm and stores the picture data in an image buffer 105. A resolution conversion part 104 extracts a character image from a CG ROM 103 and expands it on a frame memory 108. Thereafter, a gradation pattern selecting part 106 takes out data Dm stored in the buffer 105 and selects a gradation pattern corresponding to data Dm from a gradation pattern storage memory 107 and expands it on the memory 108. A print processing part 110 prints out picture data, which is enlarged (n) times ((n) is an integer) and is reconstituted on the memory in such manner, with the resolution set by a printing resolution setting part 111. Thus, the gradation of the print is improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus such as a digital copying machine, a facsimile machine, a printer, an electronic file and the like, and more particularly, to a gradation of input data without degrading the resolution. BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus and method for improving the property.

[0002]

2. Description of the Related Art Conventionally, in the case of printing out image data having gradation, in a normal binary printing apparatus (binary printer), some pixels are grouped into a block and this is divided into a plurality of pixels. The gradation expression is executed by performing the replacement process on the configured gradation pattern (dither pattern).

[0003]

However, in the conventional binary printer as described above, since it is an expression system in which the resolution of an image is replaced by gradation, resolution is ensured and gradation is improved. It is not possible to secure both. Therefore, if the number of gradations is increased, the resolution deteriorates, and conversely, if it is attempted to avoid the deterioration of the resolution, sufficient gradation cannot be obtained. Further, if the constituent pixels of the gradation pattern are made too large in order to increase the number of gradations, the gradation pattern itself appears prominently, and both resolution and gradation are deteriorated.

The present invention has been made in view of the above, and it is an object of the present invention to improve gradation in binary image output without degrading the resolution of the original image data.

[0005]

In order to achieve the above object, the present invention provides an input means for inputting image data of 1-dot multi-gradation, and a 1-dot multi-level input via the input means. Gradation pattern selecting means for selecting a gradation pattern composed of a plurality of pixels corresponding to the gradation image data; resolution converting means for variably processing the pixel density to be printed;
Enlargement processing means for converting the resolution of one pixel of dot multi-gradation image data to an integer multiple resolution, and performing conversion processing to a gradation pattern corresponding to the gradation of each pixel to reconstruct an enlarged image. The present invention provides an image forming apparatus including a print output unit that executes a print process based on the image processed by the enlargement processing unit.

Further, by inputting an identification signal indicating multi-gradation image data, the number of vertical dots, the number of horizontal dots, and the number of gradations per pixel of the gradation image to be formed are sequentially instructed to form a predetermined dot matrix. An image forming method for forming a multi-gradation image by sequentially transmitting a plurality of bits of data to each one pixel of the dot matrix after formation is provided.

[0007]

In the image forming apparatus according to the present invention, one pixel of the input 1-dot multi-tone image data is converted into a resolution of an integral multiple and is replaced with a gradation pattern corresponding to the gradation of each pixel during the conversion. Process and reconstruct the enlarged image, and execute printout.

Further, in the image forming method according to the present invention, an identification signal indicating multi-grayscale image data is input, and the number of vertical dots, the number of horizontal dots, and the number of grayscales per pixel of the grayscale image to be formed are sequentially calculated. After instructing to form a predetermined dot matrix, multi-bit data is sequentially transmitted to each pixel of the dot matrix to form a multi-gradation image, and print output is executed.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a block diagram showing the configuration of an image forming apparatus according to the present invention. In the figure, 101 is a host I / F that takes in serial input / parallel input data.
(Host interface), 102 is host I / F1
Input data processing that analyzes and separates from the data input from 01, character codes representing images and characters, commands for printer control, etc. based on the convention with the connected host computer, and executes the processing corresponding to the command. Reference numeral 103 is a CGROM for storing character images, 104 is a resolution conversion unit for performing resolution (pixel density) conversion and bitmap processing, and 105 is an image for temporarily storing 1-dot pixel multi-tone image data. A data buffer 106 is a gradation pattern selection unit that selects a gradation pattern and executes bitmap processing,
Reference numeral 107 denotes a gradation pattern storage memory that stores a gradation pattern.

Reference numeral 108 expands and arranges a character image suitable for the resolution of this apparatus, and stores the binarized data of the selected gradation pattern corresponding to the gradation of the 1-dot image of the input image. Frame memory, 10
Reference numeral 9 is a video I / F for outputting the two-dimensional image data stored in the frame memory 108 as a signal suitable for the print processing unit 110, 110 is a print processing unit for printing out the input data, and 111 is a print processing unit. A print resolution setting unit provided in the print processing unit 110 for setting the resolution (pixel density), and a print control unit 112 for controlling the entire apparatus.

Next, the operation of the image forming apparatus configured as above will be described. Based on an instruction from the print control unit 112, input data from the host side is transferred to the host I / F 10
Enter via 1. The input 1-pixel multi-gradation image data is separated into only image data by the input data processing unit 102, and further, the image data buffer 105
Stored in. Further, the resolution conversion unit 104 takes out a character image suitable for this apparatus from the CGROM 103 based on an instruction from the print control unit 112 and develops it on the frame memory 108. After that, the 1-pixel multi-gradation image data stored in the image data buffer 105 is
The gradation pattern storage unit 1 extracts the gradation pattern extracted by the gradation pattern selection unit 106 and corresponding to the image data.
07 is selected and expanded on the frame memory 108.

As described above, the one-pixel multi-gradation data is replaced with the gradation pattern during resolution conversion, and the frame memory 10
8 is expanded two-dimensionally to 8 and the image enlarged to an integral multiple is reconstructed on the frame memory 108. Subsequently, the image data formed on the frame memory 108 is the video I / F.
It is converted by 109 into a signal that can be transmitted to the print processing unit 110. The print processing unit 110 is the print resolution setting unit 1.
The processed image data is printed out based on the resolution set by 11.

FIG. 2 is an explanatory view showing an example of replacement of input data with a gradation pattern according to the present invention.
The resolution is tripled with respect to image data of 0 gradation, and further,
An example is shown in which replacement processing is performed with a gradation pattern of 3 × 3 pixels. This device prints image data transmitted from the host side at a resolution three times higher than that. In the present embodiment, the host side transmits image data at a resolution of 160 dpi, and the apparatus side that has input the image data has a triple resolution of 480.
It is illustrated in the case where the printout is performed in dpi. With the configuration of FIG. 1, the 1-pixel image of the image data transmitted from the host side is replaced with the 3 × 3 pixel image. That is, gradation expression of 10 gradations is realized by the matrix of 3 × 3 pixels. Therefore, in such a case
Since gradation printing processing is possible, multi-gradation image data having 10 gradations per pixel is converted to 3 times the resolution from the host side, and at the same time, it is equal to the gradation of each pixel. Three
It is replaced with a gradation pattern of × 3 pixels. This makes it possible to output a multi-tone image without degrading the resolution of the input image data.

FIG. 3 is an explanatory diagram showing a gradation image representation of 16 × 16 dots in multi-gradation image data according to the present invention. In this embodiment, 16 gradations are provided for each pixel,
In the case of transmitting one pixel with 4 bits, first, a control code (for example, 8 bits 16
Base 1ch, 49h (escape code 1B +
Specify a code string such as "I"). Subsequently, the dot matrix of m × n gradation image is formed by sequentially specifying the number of vertical dots m, the number of horizontal dots n, and the number of gradations 1 per pixel that form an image.

In this case, for example, when the number of vertical dots is 16, the number of horizontal dots is 16, and the number of gradations is 16 and each is expressed by an 8-bit hexadecimal number, a code string of 10h, 10h, 10h is obtained. Next, as shown in the figure, the gradation of each pixel is changed from the first (d ₀₀ ) on the left first column to the second (d ₀₁ ) on the same column, ...
From bottom to top (d _0F ), top to bottom, then image left 2
Order column first superior from (d ₁₀₎ 2 columns first currently left to (d _1F), also last image right one column presently first while moving to the right from top to bottom of (d _FF) The data is transmitted on the formed dot matrix.

In addition, in the above, for example, data 8
When transmitted in bit units, 1 pixel data is represented by 4 bits, so 4 bits of odd-numbered data correspond to 4 high-order bits and even-numbered data correspond to 4 low-order bits, and 2 pixels are transmitted at 8 bits each. can do.

As described above, in this embodiment, the resolution at the time of final printing is enlarged to an integral multiple, and a character (font character) image composed of high-density pixels corresponding to the enlarged resolution is generated. By selecting and using it, it is possible to improve the printing quality for the characters transmitted by the character code. Therefore, high-quality character output and gradation image output can be realized at the same time.

[0018]

As described above, according to the image forming apparatus of the present invention, the input means for inputting 1-dot multi-gradation image data and the plurality of pixels corresponding to the 1-dot multi-gradation image data. A gradation pattern selecting means for selecting a gradation pattern configured by the above, a resolution converting means for variably processing the pixel density to be printed, and a resolution of an integer multiple for one pixel of the one-dot multi-tone image data. Then, at the time of the conversion, an enlarging processing unit that replaces the tone pattern corresponding to the tone of each pixel to reconstruct an enlarged image, and a print output unit that executes a printing process based on the image processed by the enlarging processing unit. Since it is provided, in the binary image output, the gradation can be improved without deteriorating the resolution of the original image data.

As described above, according to the image forming method of the present invention, the identification signal indicating the multi-tone image data is input and the number of vertical dots, the number of horizontal dots, and the number of horizontal dots of the tone image to be formed are 1. A binary image is formed by sequentially instructing the number of gradations per pixel to form a predetermined dot matrix, and then sequentially transmitting a plurality of bit data to each pixel of the dot matrix to form a multi-gradation image. In the output, the gradation can be improved without deteriorating the resolution of the original image data.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of an image forming apparatus according to the present invention.

FIG. 2 is an explanatory diagram showing an example of replacement of input data with a gradation pattern according to the present invention.

FIG. 3 shows 16 in multi-tone image data according to the present invention.
It is explanatory drawing which shows the gradation image expression of * 16 dot.

[Explanation of symbols]

101 Host I / F 102 Input Data Processor 104 Resolution Converter 106 Gradation Pattern Selector 108 Frame Memory 110 Print Processor

Claims (2)

[Claims] 1. A gradation pattern composed of input means for inputting 1-dot multi-gradation image data and a plurality of pixels corresponding to the 1-dot multi-gradation image data input via the input means. A gradation pattern selecting means for selecting, a resolution converting means for variably processing a pixel density to be printed, and a resolution of one pixel of the one-dot multi-tone image data is converted into an integral multiple resolution, and each pixel is converted at the time of the conversion. And a print output unit for executing a print process based on the image processed by the enlargement processing unit. Image forming apparatus. 2. A predetermined dot matrix is formed by inputting an identification signal indicating multi-gradation image data and sequentially instructing the number of vertical dots, the number of horizontal dots, and the number of gradations per pixel of a gradation image to be formed. After the formation, a multi-tone image is formed by sequentially transmitting a plurality of bit data to each pixel of the dot matrix.