JPH10215378A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming device that forms an image without deteriorating the sharpness due to thickened lines and characters and blurred edges. SOLUTION: An under color is eliminated (S20) and a data portion of only paper is eliminated so as to avoid mis-recognition as if there are dust. Then dust at a gap is emphasized (S21). Then a magnification output is made (S22). A dust detection pattern is small depending also on recording resolution of a printer. Then the pattern is simply magnified and outputted so that a dust correction adjustment personnel easily recognizes it. A sample being an ideal output is outputted for the comparison so as to facilitate the evaluation. The operator recognizes the output and inputs a correction coefficient. After that the image processed by the correction coefficient is outputted.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to an image forming apparatus for removing dust and bleeding of a color material which is generated when output on recording paper.

[0002]

2. Description of the Related Art With the OA of offices, image forming, that is, outputting to paper, has been widely performed by color copying machines, monochrome copying machines, printers, facsimile machines, etc. which have been widely used. ing. When an image is formed on a recording member (normal / dedicated paper, OHP (overhead projector), etc.) using a recording color material (toner, ink, thermal film, etc.) with these devices, FIG.
As shown in (1), toner dust and bleeding may occur.
FIG. 18A shows an ideal output without dust, and FIG.
Is the output where dust is generated, and the shaded portion corresponds to dust.

[0003]

By the way, in the output diagram (b) of FIG. 18, the image quality is deteriorated such as thickening of lines and characters, blurring of edges, and lowering of sharpness.
This makes it impossible to provide the image desired by the user. This is due to the characteristics of the toner itself, both the toner and the paper, and the characteristics of the image forming apparatus (copier, printer). SUMMARY OF THE INVENTION It is an object of the present invention to provide an image forming apparatus capable of forming an image without thickening lines and characters, blurring edges, and reducing sharpness.

[0004]

According to the first aspect of the present invention, a dust detection pattern storing means for storing a dust detection pattern, and a dust detection pattern stored in the dust detection pattern storage means are stored in the own device. Output, reads the output image, performs image processing and enlarges and outputs the state of dust, and a correction parameter input means that inputs an appropriate dust correction parameter from the output of the enlarged output.
The above object is achieved by providing image processing means for processing an edge portion with a correction parameter input from a correction parameter input means, and image output means for outputting an image processed by the image processing means.

According to the second aspect of the present invention, the dust detection pattern storage means for storing the dust detection pattern and the dust detection pattern stored in the dust detection pattern storage means are output and output by the own device. A dust amount calculating unit that reads an image and calculates an amount of dust by performing image processing; and a correction parameter setting unit that automatically extracts an appropriate dust correction parameter from a value calculated by the dust amount calculating unit and sets the extracted dust parameter in the own device. The above object is achieved by providing image processing means for processing an edge portion with the correction parameters set by the correction parameter setting means, and image output means for outputting an image processed by the image processing means. I do.

According to the third aspect of the present invention, the dust detection pattern storage means for storing the dust detection pattern, and the dust detection pattern stored in the dust detection pattern storage means are output by the own device and output. Graphing means for reading the image, analyzing the state of dust by image processing, graphing and outputting, and inputting or automatically extracting appropriate dust correction parameters from the output of the graphing means and automatically Correction parameter setting means to be set in the image processing apparatus, image processing means for performing an edge processing with the correction parameters set by the correction parameter setting means, and image output means for outputting an image processed by the image processing means. The above-mentioned object is achieved by providing.

According to a fourth aspect of the present invention, in the image forming apparatus according to the first, second, or third aspect, after all the control relating to the density of the apparatus is completed, the dust correction parameter is set or input. Achieve the above objectives.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to FIGS. FIG.
1 is a block diagram illustrating a configuration of an image forming apparatus according to the present embodiment. The image forming apparatus includes an image reading device (scanner) 10, an image processing unit 12, an operation / display unit 14, an image forming unit (printer) 16, and an input / output interface 18. 1. The internal configuration of the image processing unit 12 shown in FIG. 1 is shown in the block diagram of FIG. The image processing unit 12 includes a device control CPU
(Central processing unit) 20, RAM (random access
Memory) 22, ROM (read only memory) 2
3. Image reading device (scanner) 10, image processing unit 12, operation / display unit 14, image forming unit (printer) 16
I / F 24 between each device, dedicated ASIC 2 for image processing
6, a pattern memory 28 for dust detection and a work memory 30 for image processing.

Next, the procedure of the processing of the first embodiment will be described with reference to the flowchart of FIG. First, when performing dust correction, an instruction to output a dust detection pattern from the operation / display unit 14 is sent to the device control CPU 20 in the image processing unit 12.
And the image stored in the dust detection pattern memory 28 is output by the printer 16 (step 1).
0). A very complicated pattern is not preferable as the dust detection pattern because it is easy to read dust and easy to read.

FIG. 4 shows an example of the dust detection pattern. It is a comb-shaped pattern of a height Hdot having a gap of an Mdot width line and an Ndot width. A marker 5a is added as a guide for reading or image processing. The width Xdot and height Ydot in the marker 5a are portions used for actual dust detection. With FIG. 4 as one block, a pattern in which chile correction has been applied to an edge portion in advance is arranged as shown in FIG. 5 and output on paper.

Here, the pattern in which the edge portion is subjected to the dust correction in advance is, as shown in FIG.
× No dot correction of Hdot = Based on a correction coefficient of 1.0,
The density is reduced from the edge portion to Tdot. Here, the correction coefficient is defined by the ratio between the point B where the density is the lowest and the non-correction point A. In the example shown in FIG. 6, since the density is reduced in steps at equal intervals, each step takes a value obtained by equally dividing the correction coefficients from 1.0 to k. Such a pattern of each coefficient is arranged on the same paper as shown in FIG.
Output. For the color of the pattern, the most scattered color that is easily visible is selected for each color material.

Next, the pattern shown in FIG. 5 is read by the scanner 10 (step 11). For this reading, gray continuous tone is sufficient. At this time, only the image in the marker of each pattern is loaded into the image processing work memory 30.

Next, the image processing (step 12) is executed by the image processing dedicated ASIC 26. Hereinafter, the process of step 12 will be described with reference to the flowchart of FIG. First, the under color is removed (step 20). Generally, when paper is read by a scanner, the paper color is also read at the same time, so that digital data also exists in a paper portion where toner does not exist (see FIG. 8A). Therefore, FIG. 8B removes the data of only the paper so as not to mistakenly recognize that there is dust.

Then, dust in the gap is emphasized (step 21). Only the dust existing in the gap portion of Ndot is emphasized (see FIG. 8C). Processing includes simple input / output table conversion, and an example of the table is shown in FIG.
FIG. 10 shows the output pattern. After that, enlarged output is performed (step 22). The dust detection pattern is small, depending on the recording resolution of the printer 16. Therefore,
The image is simply enlarged and output so as to be easily recognized by the chile correction adjuster (step 13). An enlarged view of the output at a certain correction coefficient is shown in FIG. 8 (c), and a sample which is an ideal output is also output for comparison with this, so that evaluation can be performed easily. Therefore, the final output is as shown in FIG. The operator recognizes this output and inputs a correction coefficient (step 14). Thereafter, an image processed with this correction coefficient is output.

Next, a second embodiment of the present invention will be described. In the second embodiment, the determination of the correction coefficient in the first embodiment is performed not by the operator but automatically by the apparatus. The second embodiment will be described with reference to the flowchart of FIG. The image processing procedure in step 32 in FIG. 11 is shown in the flowchart in FIG.

First, until the dust is emphasized in the gap (Step 4)
0, step 41) is common to the first embodiment.
In the emphasized image (in this case, the original size without simple enlargement) (FIG. 8C), the image size is X × Ydot. Therefore, an average of the height direction Ydot is calculated (step 42), and binarized by the threshold value Th (step 43). The result is shown in FIG. Then, the width Pdot including the dust of each line can be obtained (the value of one line or the average of each line, step 44).

Since the difference is ideally Mdot, the difference becomes the dust width, and it can be said that the less the dust, the less the dust, so the corresponding correction coefficient is picked up (step 45). At this time, it can be seen that when P> M, the thickness is increased due to dust and when P <M, the thickness is increased due to excessive correction. Since thinning particularly affects characters and thin lines in terms of image quality, P> M is prioritized. The extracted parameters are taken into the device (step 33).

Next, a third embodiment will be described. In the first embodiment, the correction coefficient is input by the operator, and in the second embodiment, the input is automatic. On the other hand, the third embodiment corresponds to a case where it is desired to know clear information as to what kind of result the correction coefficient is selected in any case. FIG. 1 is a flowchart showing the procedure of this processing.
4, shown in FIG. 14, a dust detection pattern output (step 50), scanner reading (step 51), and image processing (step 52) are performed. The processing of this step 52 is shown in the flowchart of FIG.

First, after removing the base (step 60) and emphasizing the dust in the gap (step 61), Ydot averaging is performed (step 62), and inversion is performed (step 63). Since the reading is reflection, the reading value of paper is high, and the line portion is low. Conversely, when output is performed, if the output is expressed in terms of density, it is easy to understand the level of density at the line portion. This result is graphed (step 64).
FIG. In the example of FIG. 16, the solid line represents an ideal state, the broken line represents a state with little dust, and the dotted line represents a state with many dusts. The information sheet finally output means that two graphs of ideal and analysis results for each correction coefficient and information such as PM are output on one sheet of paper.

Next, a fourth embodiment will be described. Some printers 16 are capable of controlling the amount of toner adhering to the photoreceptor and setting γ as an image input / output conversion table when the function of the printer 16 is improved. That is, the maximum recording density in the case where an image is formed on paper can be changed. The dust correction processing needs to be performed after the density control processing for the processing to reduce the edge density in the image immediately before the final output. The procedure of the process according to the fourth embodiment will be described with reference to the flowchart in FIG.
That is, control relating to the density possessed by the printer 16 is executed (step 70), and thereafter, processing for determining a dust correction parameter is executed (step 71).

[0021]

According to the first aspect of the present invention, the operator himself / herself makes a subjective evaluation based on the output of the enlargement output means, determines an appropriate dust correction parameter, and inputs the appropriate dust correction parameter from the correction parameter input means. Corrections can be made.

According to the second aspect of the present invention, the dust amount calculating means can determine the dust amount on an objective scale and determine the dust correction parameter without depending on the subjective judgment of the operator.

According to the third aspect of the invention, by outputting a sheet in which the state of dust is analyzed, the current situation of dust in the printer can be confirmed in detail, and an appropriate dust correction can be made based on the information. The parameters can be determined.

According to the fourth aspect of the present invention, by performing the dust correction after the completion of the density control of the printer itself, a stable dust correction can be realized as a result.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration of an image forming apparatus according to an embodiment.

FIG. 2 is a block diagram illustrating an internal configuration of an image processing unit.

FIG. 3 is a flowchart illustrating a procedure of a process according to the first embodiment;

FIG. 4 is a diagram illustrating an example of a dust detection pattern.

FIG. 5 is a diagram in which patterns subjected to dust correction are arranged.

FIG. 6: No dust correction of M × Hdot = correction coefficient 1.0
FIG. 3 is a diagram showing an example of the above.

FIG. 7 is a flowchart showing a procedure of a process of step 12 (image processing) in FIG. 3;

FIGS. 8A and 8B show examples of (a) a case where the background is not removed, (b) a case where only the data of the paper is removed, (c) a case where only the dust is emphasized, and (d) a final output. .

FIG. 9 is a diagram illustrating an example of input / output table conversion.

FIG. 10 is a diagram illustrating an output pattern.

FIG. 11 is a flowchart illustrating a procedure of a process according to the second embodiment;

FIG. 12 is a flowchart showing a procedure of a process of step 32 (image processing) in FIG. 11;

FIG. 13 shows an average of the height direction Ydot, and a threshold T
FIG. 9 is a diagram showing binarization by h.

FIG. 14 is a flowchart illustrating a procedure of a process according to the third embodiment;

FIG. 15 is a flowchart showing a procedure of a process of step 52 (image processing) in FIG. 14;

FIG. 16 is a graph showing the results in FIG.

FIG. 17 is a flowchart illustrating a procedure of a process according to the fourth embodiment;

FIG. 18 is a diagram illustrating an example in which toner dust and bleeding have occurred in the output of the conventional apparatus.

[Description of Signs] 10 Image reading device (scanner) 12 Image processing unit 14 Operation / display unit 16 Image forming unit (printer) 18 Input / output interface 20 Device control CPU (Central processing unit) 22 RAM (Random access memory) ) 23 ROM (Read Only Memory) 24 I / F 26 Dedicated ASIC for image processing 28 Pattern memory for dust detection 30 Work memory for image processing

Claims (4)

[Claims] 1. A chile detection pattern storage means for storing a chile detection pattern, and a chile detection pattern stored in the chile detection pattern storage means, which is output by itself, and the output image is read.
Enlargement output means for enlarging and outputting the state of dust by image processing, correction parameter input means for inputting an appropriate chile correction parameter from the output of the enlargement output means, and an edge portion with a correction parameter input from the correction parameter input means An image forming apparatus, comprising: an image processing unit that performs the processing described above; and an image output unit that outputs an image processed by the image processing unit. 2. A dust detection pattern storing means for storing a dust detection pattern, a dust detection pattern stored in the dust detection pattern storage means being output by its own device, and an output image being read.
A dust amount calculating means for calculating a dust amount by image processing; a correction parameter setting means for automatically extracting an appropriate dust correction parameter from the value calculated by the dust amount calculating means and setting the same in its own device; An image forming apparatus comprising: an image processing unit configured to perform an edge processing with a correction parameter set by a setting unit; and an image output unit configured to output an image processed by the image processing unit. 3. A chile detection pattern storage means for storing a chile detection pattern, and a chile detection pattern stored in the chile detection pattern storage means, which is output by itself, reads the output image, and reads the image. Graphing processing means for processing and analyzing the state of dust, graphing processing and outputting, and correction parameters for inputting or automatically extracting appropriate dust correction parameters from the output of the graphing processing means and setting them in the own machine Setting means; image processing means for processing an edge portion with the correction parameters set by the correction parameter setting means; and image output means for outputting an image processed by the image processing means. Image forming apparatus. 4. The image forming apparatus according to claim 1, wherein a dust correction parameter is set or input after all control relating to the density of the apparatus is completed.