JP2003226037A - Imaging method and imaging apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To complete inter-pixel correction in a short operation time by attaining a neat state without minute irregularity by a small number of operations. <P>SOLUTION: In an imaging apparatus comprising printing heads 1, 2 with a plurality of recording elements arranged in array, a printing head controlling means for driving and controlling the printing heads 1, 2 based on image data, and a conveying means 30 for conveying the printing heads, 1, 2, or a photosensitive material P, or both printing heads 1, 2 and photo sensitive material P, a density measuring means 40 for measuring the recording element densities of the image, and an imaging mode means 50 for calculating and correcting the influence of the adjacent element densities to the recording element densities obtained by the density measurement, calculating the recording characteristic correction amount of the recording elements as the true element density, and correcting and controlling the printing heads using the correction amount, are provided. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming method and an image forming apparatus for recording an image by correcting variations in recording characteristics of each recording element of a print head in which a plurality of recording elements are arranged in an array.

[0002]

2. Description of the Related Art Recently, a digital output device has a selfoc lens array on a print head in the form of an array in which fine light emitting elements are arranged at a predetermined pitch to obtain a desired resolution for high speed image recording. There is a device for recording a digital image by forming a beam spot on a photosensitive material via a.

Such a digital output device needs to be controlled with a gradation of at least 200 levels or more in order to express a gradual gradation such as the shade of a person's skin or the scenery of the sky. As a method for reproducing such gradations, a method has been proposed in which an array print head is exposed a plurality of times at a plurality of emission levels to perform multi-gradation recording of 200 levels or more.

The array-type print head described above is
An ED light emitting element or a vacuum fluorescent tube is arranged, a PLZT print head using a suitable backlight, an optical shutter array such as a liquid crystal shutter array print head, and a semiconductor laser are arranged in an array.
The light emitting elements forming the array-shaped print head generally have variations in light emitting characteristics. The variations in the light emission characteristics of the respective light emitting elements that form the array-shaped print head are directly recorded as the unevenness of the light and shade of the image.

The digital output device employing the above-described modulation method for reproducing multiple gradations of 200 levels or more becomes a decisive factor for image quality deterioration due to the above-mentioned variation in the light emission characteristics of the light emitting elements. Further, the image recording apparatus using the print head described above has a variation in the light emission amount for each light emitting element, and there is usually an error of about 20% to 40%, and a photograph or the like is displayed in continuous gradation. In order to reproduce it, it is necessary to set it to 2% or less at the minimum, and it is necessary to set it to 1% or less in order to record with higher image quality. In order to achieve the error of 2% or 1% or less, highly accurate measurement technology and calculation accuracy are required, which is very difficult.

In order to prevent such a problem, an image having a predetermined gradation is output on a photosensitive material, and the image density of the developed photosensitive material is measured to obtain a correction amount of the exposure amount for each light emitting element. It is possible to correct the exposure time by using
It is known from the specification of Japanese Patent Publication No. 1 and is called by the name of inter-pixel correction.

[0007]

The above-mentioned inter-pixel correction can solve the unevenness in the image density, but this inter-pixel correction operation cannot remove the fine unevenness in a single operation, so that the fine unevenness can be eliminated. 5 to ensure a clean condition
It has been pointed out that it is necessary to repeat the operation eight to eight times, which requires a long operation time.

The present invention has been made in view of the above circumstances, and an image forming method and an image forming method capable of reaching a clean state without fine unevenness with a small number of operations and completing inter-pixel correction in a short operation time. The purpose is to provide a device.

[0009]

In order to solve the above-mentioned problems and to achieve the object, the present invention has the following constitution.

According to the first aspect of the invention, an image is recorded on a photosensitive material based on image data by using a print head in which a plurality of recording elements are arranged in an array, and the density of the image is measured. In the image forming method of obtaining the correction amount of the recording characteristics of each recording element and correcting the image by using the correction amount, the image is an image recorded by the recording elements continuous in the recording element array direction, This is an image forming method characterized in that the effect of adjacent element densities on the measured density of each recording element is corrected by calculation and used as the true element density.

According to the first aspect of the invention, the recording element forms pixels in a dot shape on the photosensitive material.
Since it is mountain-shaped, has a wide base, and is influenced by the adjacent pixel that overlaps the adjacent pixel portion and also affects the adjacent pixel, a simulation of the contribution of this adjacent element is performed. Thus, by obtaining the true density of the element and using it for the correction value calculation, it is possible to reach a clean state without fine unevenness with a small number of operations and complete the inter-pixel correction in a short operation time.

According to a second aspect of the present invention, the photosensitive material is silver halide color paper, and a characteristic curve of the photosensitive material is used in converting the density measurement data into exposure amount data. The image forming method according to claim 1.

According to the second aspect of the present invention, the characteristic curve of the silver halide color paper is used to reach a clean state without fine unevenness with a small number of operations, and the inter-pixel correction is completed in a short operation time. Can be made.

The invention according to claim 3 is the image forming method according to claim 1 or 2, wherein a calculation formula for obtaining the true density of each recording element from each density of the recording elements is as follows. .

D (I) = D (i) + α (2D (i) -D
(I + 1) -D (i-1)) D (I): true element density α: adjacent element contribution rate D (i): i-th element density D (i + 1): i + 1-th element density D (i- 1): i-1th element density According to the invention described in claim 3, the true recording element density is calculated from each recording element density by a calculation formula, so that the number of operations is small and there is no fine unevenness. It is possible to reach the state and complete the inter-pixel correction in a short operation time.

According to a fourth aspect of the present invention, a print head in which a plurality of recording elements are arranged in an array, print head control means for driving and controlling the print head based on image data, the print head, or the print head In an image forming apparatus having a photosensitive material, or a transport means for transporting both the print head and the photosensitive material,
From the density measurement means for measuring the density of each recording element of the image and the images recorded by the continuous recording elements, the effect of the adjacent element density on each measured density of the recording elements is corrected by calculation to obtain a true value. An image forming apparatus comprising: an image forming mode unit that obtains a correction amount of a recording characteristic of each recording element as an element density and corrects and controls the print head using the correction amount.

According to the fourth aspect of the invention, the recording element forms pixels in a dot shape on the photosensitive material.
Since it is mountain-shaped, has a wide base, and is influenced by the adjacent pixel that overlaps the adjacent pixel portion and also affects the adjacent pixel, a simulation of the contribution of this adjacent element is performed. Thus, by obtaining the true density of the element and using it for the correction value calculation, it is possible to reach a clean state without fine unevenness with a small number of operations and complete the inter-pixel correction in a short operation time.

According to a fifth aspect of the present invention, the photosensitive material is silver halide color paper, and a characteristic curve of the photosensitive material is used in converting the true element density data into exposure amount data. The image forming apparatus according to claim 4.

According to the invention described in claim 5, by using the characteristic curve of the silver halide color paper, a fine state without fine unevenness can be reached with a small number of operations, and the inter-pixel correction is completed in a short operation time. Can be made.

The invention according to claim 6 is the image forming apparatus according to claim 4 or 5, characterized in that the formula for obtaining the true density of each recording element from the density of each recording element is as follows. .

D (I) = D (i) + α (2D (i) -D
(I + 1) -D (i-1)) D (I): true element density α: adjacent element contribution rate D (i): i-th element density D (i + 1): i + 1-th element density D (i- 1): i-1th element density According to the invention described in claim 6, by calculating the true recording element density from the recording element density by a calculation formula, it is possible to perform a clean operation without fine unevenness with a small number of operations. It is possible to reach the state and complete the inter-pixel correction in a short operation time.

According to a seventh aspect of the invention, a scanner capable of measuring the recording element size by dividing the recording element into 2 to 10 is used for each recording element density measurement, and an average value obtained by dividing the recording element density is measured. 7. The image forming apparatus according to claim 4, wherein the read value of the recording element density is used.

According to the seventh aspect of the present invention, a scanner is used for measuring the density of each recording element, and the average value obtained by dividing the density of the recording element is measured as the recording element density reading value. It is possible to reach a clean state without fine unevenness by the number of times and complete the inter-pixel correction in a short operation time.

[0024]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of an image forming method and an image forming apparatus according to the present invention will be described in detail below with reference to the drawings, but the present invention is not limited to this embodiment.

FIG. 1 is a schematic configuration diagram of an image forming apparatus, and FIG. 2 is a plan view showing image light from print heads arranged side by side.

The image forming apparatus according to this embodiment has print heads 1 and 2 having a plurality of recording elements arranged in an array.
And a print head control means 20 for driving and controlling the print heads 1 and 2 based on image data, and a transport means 30 for transporting the photosensitive material P. A large number of recording elements are arranged in a line in the main scanning direction in the print heads 1 and 2 of this embodiment, and the print heads 1 and 2 are arranged in the carrying direction for each exposure of blue light, green light, and red light. They are arranged in order.

The conveying means 30 has a conveying path formed by a pair of conveying rollers 3 and 4 arranged in a plurality of stages.
Blue light, green light, and red light print heads 1 and 2 are arranged between a pair of conveyance rollers 3 and 4 along the conveyance path.
A photosensitive material P such as color paper is conveyed by the pair of conveying rollers 3 and 4, and digital image exposure is performed from the print heads 1 and 2. In this embodiment, the transport means 30 is configured to transport the photosensitive material P, but it may be configured to transport the print heads 1 and 2, or the print heads 1 and 2 and the photosensitive material P. Both may be configured to be transported.

The image forming apparatus of this embodiment has a density measuring means 40 and an image forming mode means 50. The density measuring unit 40 conveys a photosensitive material P such as color paper, performs digital image exposure from the print heads 1 and 2, and reads a developed print using a scanner 60 to determine the density of each recording element of an image. taking measurement.

The scanner 60 uses a flat bed scanner capable of measuring the recording element size by dividing the recording element size into 2 to 10 for each recording element density measurement, and records the average value obtained by dividing and measuring the recording element density. Use the element density reading.

The image forming mode means 50 corrects the effect of the adjacent element densities on the density of each recording element whose density is measured from the images recorded by the continuous recording elements and calculates the true element density. The correction amount of the recording characteristics of the recording element is calculated, and the correction amount is used to print heads
Correction control.

The light-sensitive material P is a silver halide color paper, and the characteristic curve of the light-sensitive material is used to convert the true element density data into the exposure amount data.

In the correction of the print head 1 and the print head 2 of this embodiment, the unevenness is corrected for each head as shown in FIG. 3 (a), and uniformized as shown in FIG. 3 (b). , The density of the left and right print heads 1 and 2 is adjusted, and as shown in FIG. 3C, adjustment is performed so that the densities are the same.

As for each element density, as shown in FIG. 4, pixels are formed in a dot shape on the photosensitive material, but in a mountain shape,
It has a wide skirt and overlaps the adjacent pixel part.
Conventionally, the peak portion of a mountain of a dot-shaped pixel is measured and used as the pixel density, but in this embodiment, it is influenced by a pixel adjacent to the adjacent pixel and affects the adjacent pixel. Therefore, the true density of the element is obtained by performing a simulation regarding the contribution of the adjacent element, and is used for the correction value calculation.

The true element density di is di = Di + 2αD
i-αDi-1-αDi + 1, 2αDi is the protrusion to both sides, and αDi-1 and αDi + 1 are the protrusions from both sides. With this calculation, the true density of each recording element is calculated from the density of each recording element. Formula, D (I) = D (i) + α (2D (i) −D (i + 1) −
D (i-1)) was calculated.

D (I): true element density α: adjacent element contribution rate D (i): i-th element density D (i + 1): i + 1st element density D (i-1): i-1th The element density, which is the adjacent element contribution rate α, is determined by previously determining the pixel size and the degree of overlap by experiments or the like.

As described above, the true density of the element is obtained by performing the simulation regarding the contribution of the adjacent element,
By using the correction value calculation, it is possible to reach a clean state without fine unevenness with a small number of operations, and complete the pixel-to-pixel correction in a short operation time.

[0037]

As described above, claim 1 and claim 4
In the invention described in (1), the recording element forms pixels in a dot shape on the photosensitive material, but has a mountain shape, has a wide base, and is influenced by the pixel adjacent to the pixel portion overlapping the adjacent pixel portion. Moreover, since the adjacent pixels are affected, the true density of the element is obtained by performing a simulation regarding the contribution of the adjacent element, and the true density of the element is used for calculation of the correction value. It is possible to reach a neat state without any problem and complete the inter-pixel correction in a short operation time.

In the invention described in claims 2 and 5,
Use the characteristic curve of silver halide color paper to reach a clean state without fine unevenness with a small number of operations.
Inter-pixel correction can be completed in a short operation time.

In the invention described in claims 3 and 6,
By obtaining the true print element densities from the print element densities by a calculation formula, it is possible to reach a clean state without fine unevenness with a small number of operations and complete the inter-pixel correction in a short operation time.

According to the invention described in claim 7, a scanner is used for measuring the density of each recording element, and the average value obtained by dividing and measuring the density of the recording element is used as the recording element density reading value, so that the number of fine operations can be reduced with a small number of operations. It is possible to reach an even and clean state and complete the inter-pixel correction in a short operation time.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of an image forming apparatus.

FIG. 2 is a plan view showing image light from print heads arranged side by side.

FIG. 3 is a diagram illustrating correction of image density of print heads arranged side by side.

FIG. 4 is a diagram showing that pixels are formed in a dot shape on a photosensitive material and overlap with an adjacent pixel portion.

[Explanation of symbols]

1,2 print head 20 Printhead control means 30 transportation means 40 Concentration measuring means 50 image forming mode means P photosensitive material

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Masayuki Kurematsu             Konica Stock, 1 Sakura-cho, Hino City, Tokyo             In the company F-term (reference) 2C162 AE12 AE14 AE23 AE28 AE47                       AE77 AF20 AF44 AF53 AF83                       FA04 FA17

Claims (7)

[Claims] 1. A print head in which a plurality of recording elements are arranged in an array is used to record an image on a photosensitive material based on image data, and the density of the image is measured to determine the recording characteristics of each recording element. In an image forming method of obtaining a correction amount and correcting and recording an image using the correction amount, the image is an image recorded by recording elements continuous in the recording element array direction, and the density of each recording element measured Compensate for the influence of adjacent element density by calculation,
An image forming method characterized by being used as a true element density. 2. The image according to claim 1, wherein the light-sensitive material is silver halide color paper, and the characteristic curve of the light-sensitive material is used in converting the density measurement data into exposure amount data. Forming method. 3. The image forming method according to claim 1, wherein a calculation formula for obtaining the true density of each recording element from the density of each recording element is as follows. D (I) = D (i) + α (2D (i) −D (i + 1) −
D (i-1)) D (I): true element density α: adjacent element contribution rate D (i): i-th element density D (i + 1): i + 1-th element density D (i-1): i -1st element density 4. A printhead having a plurality of recording elements arranged in an array, printhead control means for driving and controlling the printhead based on image data, the printhead, the photosensitive material, or the printhead. And an image forming apparatus having a conveying unit that conveys both the light-sensitive material and the photosensitive material, and a density measuring unit that measures the density of each recording element of the image, and each recording element whose density is measured from the images recorded by continuous recording elements. An image forming mode in which the effect of adjacent element densities on the density is corrected by calculation to obtain the correction amount of the recording characteristic of each recording element as the true element density, and the print head is corrected and controlled using this correction amount. An image forming apparatus comprising: 5. The characteristic curve of the light-sensitive material is used when the light-sensitive material is silver halide color paper and the true element density data is converted into exposure amount data. Image forming device. 6. The image forming apparatus according to claim 4, wherein the formula for obtaining the true density of each recording element from the density of each recording element is as follows. D (I) = D (i) + α (2D (i) −D (i + 1) −
D (i-1)) D (I): true element density α: adjacent element contribution rate D (i): i-th element density D (i + 1): i + 1-th element density D (i-1): i -1st element density 7. A scanner capable of measuring by dividing the size of the recording element into 2 to 10 is used for each recording element density measurement,
7. The image forming apparatus according to claim 4, wherein an average value obtained by dividing and measuring the density of the recording element is used as the recording element density reading value.