JP2002072364A - Image recording device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a digital print of high picture quality by making proper shading corrections of all gradations. SOLUTION: This image recording device is equipped with a sensor 12 which measures the exposure quantities of respective light output parts of an exposure head, a measurement control part 21 which controls the respective light output parts and sensor 12 so as to measure the exposure quantities in plural gradations, a correction data calculation part 22 which generates correction data for correcting the exposure quantities of measured gradations by the gradations according to the measurement data, an interpolative operation part 23 which generates correction data for correcting the exposure quantities of unmeasured gradations by performing interpolative operation according to the correction data of the measured gradations calculated by the correction data calculation part 22, and an exposure data output part 25 which corrects the exposure quantities of the respective light output parts of the exposure head according to the correction data generated by the correction data calculation part 22 and interpolative operation part 23.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image recording apparatus provided with an exposure head for controlling exposure of a photographic paper as a photosensitive material in accordance with image data. The present invention relates to an image recording apparatus that can be driven well.

[0002]

2. Description of the Related Art Conventionally, various image recording apparatuses called digital line exposure devices have been proposed. This type of image recording apparatus captures a film image or the like as image data, exposes photographic paper in accordance with the captured image data, and records an image on the photographic paper.

[0003] Exposure control in such an image recording apparatus is usually performed by an exposure unit. The above-mentioned exposure unit is composed of, for example, an exposure head, a light source, and an optical fiber bundle for guiding light from the light source to the exposure head. The exposure heads are arranged one-dimensionally in a direction (width direction of the photographic paper) orthogonal to the transport direction of the photographic paper, and a shutter unit (light output) for controlling transmission and blocking of light for each pixel (dot). Part).

In such a configuration, when a driving voltage corresponding to image data is applied to a shutter portion at a position corresponding to a desired pixel, the shutter portion opens, and light from a light source introduced into the shutter portion is printed. It is output in the paper direction and the photographic paper is exposed. Thereby, the desired pixel can be recorded.

Further, in an image recording apparatus which has been conventionally proposed, a sensor for measuring an exposure amount of each shutter portion can be scanned at a position facing the exposure head along the arrangement direction of each shutter portion. Is provided. Then, for example, the shutter opening time can be adjusted for each shutter unit based on the measurement value of the sensor. That is,
In the above image recording apparatus, based on the measurement result of the sensor,
The image quality can be improved by correcting the exposure amount according to the light output characteristics for each shutter unit.

[0006]

In a conventionally proposed image recording apparatus, when exposure is performed by a one-dimensional array head, so-called shading, which corrects output data in order to eliminate variations in the exposure amount for each dot, is known. Correction had been made.

Specifically, for a certain gradation, the output light from each shutter section is measured by a sensor, and correction data is generated for each shutter section. Exposure was performed by correcting the exposure amount for the tone.

However, the variation in the exposure amount of the shutter section often has different characteristics for each gradation.
There is a problem that one gradation can be corrected properly, but the other gradations cannot be corrected properly.

FIG. 4 shows pulse width modulation (PWM (pulse width modulation) (PWM (pulse width modulation)
FIG. 9 is an explanatory diagram showing a state of output light when a drive voltage subjected to e width modulation) is applied. As shown in FIG.
Due to the response characteristics of the shutter element, even when a pulse-like constant voltage is applied, the waveform of the rising edge of the output light is rounded.
Also, even if the drive voltage is turned off, the light cannot be completely blocked,
Light leakage occurs.

Therefore, since the gradation by the shutter element is determined by the amount of light output in a unit cycle, the gradation of the output light transmitted through the shutter element is lower than the gradation of the drive voltage in the above-mentioned waveform rounding and leakage. It is shifted by light.

For this reason, the difference between the gradation of the output light and the gradation of the driving voltage is not constant but differs for each gradation. That is, as shown in FIG. 4, the influence of the waveform rounding of the pulse width portion on the output light, that is, the area of the waveform rounding with respect to the area of the output light is small at the gray scale with the large pulse width and small at the gray scale with the small pulse width. large. Similarly, the effect of the leaked light on the output light, that is, the area of the leaked light with respect to the area of the output light is small at a gray scale having a large pulse width and is large at a gray scale having a small pulse width.

Further, as shown by a solid line and a broken line in FIG. 4, the response (time) of the shutter element and the magnitude of the leakage light differ from one shutter element to another. On the other hand, the drive voltage (constant voltage) applied to the shutter element can control only the pulse width of the waveform of the output light corresponding to the application time (ON state). Therefore, the amount of correction of the drive voltage application time differs depending on the magnitude of the leak light.

As described above, since the variation in the exposure amount among the shutter elements differs for each gray level, the conventionally proposed correction method of measuring one gray level to generate correction data does not perform the measurement. Unable tones cannot be properly corrected. As a result, for example, when printing an image having a smooth gradation in the sub-scanning direction, a streak in the sub-scanning direction may occur at the dot boundary of the exposure head.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object of the present invention is to provide an image recording apparatus capable of performing high-quality shading correction at all gradations and producing a high-quality digital print. It is to provide a device.

[0015]

In order to solve the above-mentioned problems, an image recording apparatus according to the first aspect of the present invention drives each light output unit of an exposure head according to image data to transmit light. In the image recording apparatus that records an image on a photosensitive material by controlling the light output, the light output based on the measurement data measured by the measurement means, Correction means for correcting the exposure amount of the unit, and measurement control means for controlling each of the light output units and the measurement means so as to measure the exposure amount of each of the light output units for a plurality of gradations. It is characterized by having.

With the above arrangement, when correcting the exposure amount of each light output section, the measurement control means controls each light output section and the measurement means, and for each of a plurality of gradations (measurement gradations), the measurement control section controls the light output section and the measurement means. In order to measure the exposure amount, measurement data of a plurality of gradations can be collected.

Therefore, the image recording apparatus can correct the exposure amount of the light output section based on the measurement data of a plurality of gradations. It is possible to create a high quality digital print by performing shading correction with good quality even at the gradation of.

According to a second aspect of the present invention, in order to solve the above-mentioned problems, in addition to the image recording apparatus according to the first aspect, the image recording apparatus further comprises: Correction data generating means for generating correction data for correcting the exposure amount of the light output section in the measured gradation for each gradation, and based on the measured gradation correction data generated by the correction data generating means. And interpolating means for generating correction data for correcting the amount of exposure of the light output unit at a gradation not measured by performing an interpolation operation.

According to the above arrangement, when correcting the exposure amount of each light output unit, the correction data generating means converts correction data of the measured gradation for each gradation based on the measurement data measured by the measuring means. In addition to the generation, the interpolation unit can generate the correction data of the gradation that has not been measured by the interpolation calculation based on the correction data of the measured gradation generated by the correction data generation unit.

Thus, it is possible to accurately obtain correction data for each light output unit and for each gradation. Therefore,
Even if the variation in the exposure amount between the light output units differs for each gradation, the image data can be properly corrected at the time of exposure using the correction data corresponding to the exposure gradation.

Therefore, shading correction can be performed with high quality for all gradations, and a high quality digital print can be created. In particular, by interpolating non-measured gradations, gradation-based correction data is uniformly set for all light output units (dots) based on correction data generated by measuring one gradation as in the related art. As a result, there is no step (streak) at the gradation change (correction data change).

According to a third aspect of the present invention, in order to solve the above-mentioned problems, in addition to the image recording apparatus of the first or second aspect, the measurement control means further comprises:
It is characterized in that the light output is measured in a light-shielded state of the light output section.

According to the above configuration, since the measurement control means measures the light quantity of the light output section in the light-shielded state, the correction means can correct the exposure amount of the light output section in consideration of the light quantity in the light-shielded state. .

For example, when the light output section is an electric shutter element and the exposure amount is controlled by applying a pulse width modulated drive voltage, the light output section is exposed when the drive voltage is ON, and the drive voltage is Is off, the light output section is in a light-blocking state. Here, there is an individual difference in the shutter element as the light output unit, and the response characteristics to the drive voltage are different. Therefore, the exposure amount of the light output unit is corrected by adjusting the pulse width applied to the light output unit.

However, even when the electric shutter element is in a light-blocking state, that is, in a non-driving state, it is not possible to completely block light, which may cause leakage light. Note that the amount of leaked light also differs for each shutter element.

Therefore, when correcting the exposure amount of each light output unit, it is necessary to make correction in consideration of leakage light for each light output unit.

In this regard, according to the above configuration, since the measurement control unit measures the amount of leaked light from the light output unit, the correction unit can correct the exposure amount of the light output unit in consideration of the leaked light. It becomes possible. Therefore, the image recording apparatus can perform high-quality shading correction at any gradation and create a high-quality digital print.

According to a fourth aspect of the present invention, there is provided an image recording apparatus according to any one of the first to third aspects, in order to solve the above problem.
In addition to the image recording apparatus described in the paragraph, further, the exposure head is one in which the light output portion is one-dimensionally arranged in a direction orthogonal to a direction in which the photosensitive material is transported, and exposes the transported photosensitive material. It is characterized by being.

According to the above configuration, when correcting the exposure amount of each light output unit of the exposure head of the digital line exposure device, the measurement control unit controls each light output unit and the measurement unit, and a plurality of gradations ( Since the exposure amount of each light output unit is measured for (measurement gradation), measurement data of a plurality of gradations can be collected.

Therefore, the digital line exposure device, which is the above-described image recording apparatus, can correct the exposure amount of the light output section based on the measurement data of a plurality of gradations, so that it is corrected based on the measurement data of one gradation. Compared to the case, it is possible to perform high-quality shading correction at any gradation and create a high-quality digital print.

According to a fifth aspect of the present invention, there is provided an image recording apparatus according to any one of the first to fourth aspects, in order to solve the above problem.
In addition to the image recording apparatus described in the item, the light output section is a PLZT element.

With the above configuration, the PLZT element has both high translucency and an electro-optical effect that the birefringence changes when a voltage is applied. For example, a light emitting diode, a liquid crystal, a fluorescent display tube, etc. Since the exposure head has an excellent exposure capability as compared with the above, it is possible to reliably form high-definition dots by configuring the exposure head with a PLZT element.

[0033]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to FIGS.

As shown in FIG. 2, the image recording apparatus according to the present embodiment includes a magazine 1, an image recording unit 2, and a development processing unit 3.

In the magazine 1, unexposed and undeveloped photographic paper (photosensitive material) 4 is stored in a roll state. The printing paper 4 is transported from the magazine 1 into the image recording unit 2. The photographic paper 4 pulled out from the magazine 1 into the image recording unit 2 is cut into a desired size (print size) by a cutter 5 and exposed to an exposure unit (PLZT).
It is transported to an exposure position facing the exposure unit 6.

The exposure section 6 is provided with a PLZT head (exposure head) 7 described later. The control unit 8 is connected to the exposure unit 6. Image data obtained by reading a film such as a negative / positive or a reflection original from the control unit 8 to the PLZT head 7 of the exposure unit 6;
Image data and the like created by the personal computer are sent. Note that a scanner unit that scans the film, an image editing unit that edits an image, and the like may be connected to the control unit 8, and the control unit 8 may receive image data therefrom.

The PLZT head 7 has a PLZT element made of a transparent ferroelectric ceramic material disposed between a pair of polarizing plates (a polarizer and an analyzer). PLZT element
Lead zirconate (PbZrO ₃ ) and lead titanate (PbTi
O ₃ ) and a solid solution in an appropriate ratio (PZT)
And hot-pressed with lanthanum added (P
_{b 1-x La x) (} Zr y Ti 1-y) is a _{1-x /} 4 O ₃ solid solution.

A light source 10 described later is connected to the PLZT head 7 via an optical fiber bundle 9. The PLZT head 7 is divided into dots corresponding to pixels. Each dot forms a shutter unit (light output unit) that can independently control the transmission of light from the light source 10 and the blocking thereof. Each shutter unit is one-dimensionally arranged in a direction (width direction of the photographic paper 4) orthogonal to the conveying direction of the photographic paper 4.

The PLZT head 7 has a high translucency and an electro-optical effect that a birefringence changes when a voltage is applied. Then, by applying a drive voltage according to the image data to the shutter portion at the position corresponding to the desired pixel, it becomes possible to control the above-described transmission of light and its prevention. That is, by controlling the application of the driving voltage, the polarization state of the light linearly polarized by the polarizer is controlled when the light passes through the PLZT element.
Specifically, when transmitting light, the polarization direction of the light is made parallel to the polarization plane of the analyzer. When blocking transmission of light, the polarization direction of the light and the polarization plane of the analyzer are blocked. Are orthogonal to each other.

In this embodiment, the exposure resolution of the PLZT head 7 is set to 400 DPI (dot per inch). Further, the PLZT head 7 is constituted by using ten chips each having about 512 dots. Therefore,
The width of the PLZT head 7 is 325 mm and 305 mm
The printing paper 4 having a width of about 12 inches can be accommodated with a margin. The image data of 5120 dots is PLZT corresponding to each dot (shutter portion).
It is sent to the head 7.

The photographic paper 4 is exposed by the exposure unit 6 having such a PLZT head 7. During the exposure, the photographic paper 4 is conveyed at a speed synchronized with the driving of the PLZT head 7 under the control of the control unit 8.

Printing paper 4 exposed in image recording section 2
Is transported to the development processing unit 3. The development processing section 3 includes a development section and a drying section. The developing section has processing layers each containing a processing solution of a color developing solution, a bleaching solution, a fixing solution, and a stabilizing solution. The exposed photographic paper 4 is developed by being sequentially immersed in each of these processing solutions. The drying unit dries the photographic paper 4 developed in the developing unit. The photographic paper 4 dried in the drying unit is discharged to the outside of the apparatus as a finished print 14 one by one.

Further, the image recording section 2 is provided with a measuring section 11 on the back side of the printing paper 4 at the exposure position. The measuring unit 11 has a sensor (measuring means) 12 and a sensor stage 13 for moving the sensor 12. The sensor stage 13 has a ball screw, and causes the sensor 12 to scan in the dot arrangement direction of the PLZT head 7 under the control of the control unit 8. The sensor 12 is P
The output light (transmitted light) from the LZT head 7 is read for each dot. The measurement data read by the measurement unit 11 is used by the control unit 8 to generate correction data for equalizing the amount of transmitted light for each dot. And
At the time of exposure after measurement, exposure is performed using exposure data in which this correction data is added to image data.

Hereinafter, generation of correction data and correction of image data based on the correction data in the control unit 8 will be described in detail.

FIG. 3 is an explanatory diagram showing a method of generating correction data for correcting the exposure amount of each gradation in the image recording apparatus according to the present embodiment. That is, as shown in FIG. 3, the image recording apparatus has a plurality of gradations (hereinafter, referred to as “measurement gradations”) (0, 63, 127, 191, 25).
Regarding 5), the amount of output light from the PLZT head 7 is measured to calculate correction data, and for other gradations, correction data is generated by performing an interpolation operation based on the correction data of the measured gradation. Then, the image recording apparatus corrects the image data with correction data corresponding to the gradation and performs exposure.

FIG. 1 shows a configuration provided for the control section 8 to perform the correction processing. That is, as shown in FIG. 1, the control unit 8 includes a measurement control unit (measurement control unit) 2
1, a correction data calculation unit (correction data generation unit) 22, an interpolation calculation unit (interpolation unit) 23, a correction data storage unit 24, and an exposure data output unit (correction unit) 25.

The measurement control unit 21 is provided with the PLZT head 7
And the sensor 12 and the sensor stage 13 of the measuring section 11 to measure the light quantity of the measured gradation. In particular,
Each dot of the PLZT head 7 is set to, for example, four gradations (63, 1
27, 191, 255), and the output light is read by the sensor 12 for each dot. In addition, each dot of the PLZT head 7 is set to an OFF state (non-driving state), and the detected leakage light is read by the sensor 12 for each dot.

Here, the higher the number of measured gradations (4 in the above example) to be measured by the measurement control section 21, the better the correction accuracy is, but the measurement takes time in accordance with the number of gradations. In this regard, the number of levels that can be supplemented by interpolation may be obtained by experiment, and the number of measured gradations may be determined based on the result.

The gradations (63, 127, 191, 255 in the above example) to be measured by the measurement control unit 21 may be measured uniformly from a low density range to a high density range. It is desirable to mainly measure the intermediate density range (intermediate gradation) on photographic paper having high sensitivity. That is, unless the intermediate density range on the photographic paper is accurately corrected, the variation in the exposure amount for each shutter element becomes conspicuous on the actual photographic image. Therefore, compared to the low-density area and the high-density area where the variation in the exposure amount is not so noticeable, the variation in the exposure amount for each shutter element on the photographic image can be made less noticeable by measuring a large number in the intermediate density area. it can. Considering the response, the low-density region is emphasized.

The correction data calculation unit 22 includes the sensor 12
Based on the measurement data of the measurement gradation read at
Correction data for equalizing the exposure amount (transmitted light amount) for each dot of the ZT head 7 is calculated for each gradation.

Here, in the present embodiment, the correction data of the measured gradation in the correction data calculation section 22 is calculated according to the following equation (1). Expression (1) represents all the gradations measured by the measurement control unit 21 (63, in the above example,
127, 191, 255).

[0052]

(Equation 1)

The correction data is calculated as 0.95 or 1.05 with 1.0 as the center.

In the above equation (1), the correction data is calculated in consideration of the leak light level. Here, the leak light is light that cannot be controlled by ON / OFF of the shutter element. However, if the height of the leak light is known, the time during which only the leak light occurs coincides with the time when the shutter element is in the OFF state, so that the amount of transmitted light due to the leak light can be obtained (FIG. 4). Therefore, in the above equation (1), the correction amount is reduced if the leakage light is strong, and the correction amount is increased if the leakage light is weak.

The ON light amount means that the shutter element is ON.
It is the integral value of the light energy within the measurement time when the measurement is performed. O
The FF light amount is an integrated value of light energy within a measurement time when the shutter element is turned off. The coefficients (1.366 and 0.366) in the above equation (1) are as follows: the actual exposure time A is 833.3 μs, and the measurement time B is 610.0 μs.
When s, the measurement time is converted to the actual exposure time. Note that A / B = 1.366. Therefore, these coefficients can be appropriately set according to the actual exposure time and the measurement time.

Based on the correction data at the measured gradation calculated by the correction data calculation unit 22, the interpolation calculation unit 23 equalizes the exposure amount (transmitted light amount) for each dot of the PLZT head 7 for the other gradations. Is generated by interpolation calculation. For example, in FIG. 3, the correction data of the gradations 1 to 62 is obtained based on the correction data of the gradations 0 and 63 which are the measured gradations. In addition,
The interpolation in the interpolation calculation unit 23 may be linear interpolation,
The calculation may be performed by another interpolation method.

The correction data storage unit 24 stores the PLZ generated by the correction data calculation unit 22 and the interpolation calculation unit 23.
It is a rewritable LUT (lookup table) that stores correction data for all gradations for each dot of the T head 7. The correction data written in the correction data storage unit 24 is output to the exposure data output unit 25 by PLZT.
The data is read out based on the dot position of the head 7 and the gradation of the image data.

The exposure data output unit 25 converts the input image data into the correction data according to the dot position and gradation at the time of exposure after generating the correction data and storing it in the correction data storage unit 24. The exposure data corrected by the correction data read from the unit 24 is output to the PLZT head 7. Specifically, exposure data is generated by multiplying the input image data by the correction data.

As described above, the image recording apparatus according to the present embodiment drives each light output section of the exposure head in accordance with the image data to control the light transmission state, thereby forming an image on the photosensitive material. An image recording apparatus for recording, comprising: a sensor for measuring an exposure amount of each light output unit of an exposure head; and a measurement control for controlling each light output unit and the sensor to measure the exposure amount for a plurality of gradations. And a correction data calculating unit 22 that generates correction data for correcting the amount of exposure in the measured gradation for each gradation based on the measurement data.
And an interpolation calculation based on the measured gradation correction data calculated by the correction data calculation unit 22,
An interpolation operation unit 23 that generates correction data for correcting the exposure amount at the gradation that is not measured; and each light output unit of the exposure head based on the correction data generated by the correction data calculation unit 22 and the interpolation operation unit 23. And an exposure data output unit 25 for correcting the amount of exposure. Further, in the exposure head, the light output units are one-dimensionally arranged in a direction orthogonal to a direction in which the photosensitive material is transported, and expose the transported photosensitive material.

Thus, in the image recording apparatus, when performing shading correction, several types of gradations (measurement gradations) are measured to generate correction data. In addition, correction data is generated for gray scales other than the measured gray scale by performing an interpolation operation based on the correction data of the measured gray scale. Therefore,
At the time of exposure, image data (output data) can be corrected with correction data corresponding to the exposure gradation.

Therefore, since the variation in the exposure amount between the light output units is corrected for each gradation, the shading correction is performed with good quality for all gradations, and a high-quality digital print can be created. In particular, by interpolating non-measured gradations, correction data for each gradation is set uniformly for all light output units (dots) based on correction data generated by measuring one gradation as in the past. There is no step (streak) at the gradation change (correction data change) due to this.

The present embodiment does not limit the scope of the present invention, and various changes can be made within the scope of the present invention.

That is, in the present embodiment, correction values are obtained for all gradations and correction is performed. However, gradations are divided into a plurality of groups to the extent that steps (streaks) do not occur at transitions between gradations. Alternatively, correction may be performed by obtaining correction data (correction value) for each group.

In this embodiment, pulse width modulation (PWM) is performed according to image data.
n)) The case where the drive voltage is applied to the shutter unit has been described, but the modulation of the drive voltage is not limited to this.

In the present embodiment, the exposure head is set to P
Although the configuration is made using LZT elements, it is also possible to configure the exposure head with, for example, an LED (light emitting diode) array, a liquid crystal, a fluorescent display tube, or the like, in addition to the above-described PLZT elements. However, the PLZT element has a higher exposure capability than the other members described above, and can therefore form high-definition dots. Further, the response speed of the PLZT element is very fast, and the light transmittance ratio at the time of ON / OFF is 2
000: 1, and has advantages such as a wide operating temperature range and a long life. In addition, the liquid crystal has a low response speed and leaks light, so the correction method of the present embodiment is particularly effective.

The image recording apparatus according to the present invention can be configured as follows.

The above image recording apparatus is an image recording apparatus for recording an image while transporting the photosensitive material by a recording head in which a plurality of dots are one-dimensionally arranged in a direction orthogonal to the direction of transport of the photosensitive material. And a control unit for correcting output data based on the data measured by the measuring unit, and measuring the light amount variation in a plurality of gradations.

Further, the image recording apparatus interpolates the measured gradations to generate correction data of gradations other than the plurality of gradations to be measured by the control unit, and generates the correction data in the generated correction data. May be configured to correct the output data.

Further, the image recording apparatus may be configured so that, in addition to the plurality of gradations, a gradation in a print head non-driving state is additionally measured.

[0070]

According to the first aspect of the present invention, there is provided an image recording apparatus comprising:
As described above, in the image recording apparatus that records an image on a photosensitive material by driving each light output unit of the exposure head according to the image data to control the light transmission state, Measuring means for measuring the amount of exposure, and correcting means for correcting the amount of exposure of the light output unit based on the measurement data measured by the measuring means, and a plurality of the amount of exposure of each light output unit And a measurement control means for controlling each of the light output sections and the measurement means so as to measure the gray scale.

Therefore, when correcting the exposure amount of each light output unit, the measurement control unit controls each light output unit and the measurement unit, and the exposure amount of each light output unit for a plurality of gradations (measurement gradations). , Measurement data of a plurality of gradations can be collected.

Therefore, the image recording apparatus can correct the exposure amount of the light output section based on the measurement data of a plurality of gradations, so that the amount of exposure can be reduced as compared with the case of correcting based on the measurement data of one gradation. In this case, there is an effect that it is possible to perform shading correction with high quality even in the case of the gray scale and create a high-quality digital print.

As described above, the image recording apparatus according to the second aspect of the present invention further includes, in addition to the configuration according to the first aspect,
Correction data generating means for generating, for each gradation, correction data for correcting the exposure amount of the light output section at the measured gradation based on the measurement data measured by the measuring means; and generating the correction data by the correction data generating means. Interpolating means for generating correction data for correcting the amount of exposure of the light output unit in the non-measured gradation by performing an interpolation operation based on the measured gradation correction data. It is.

Therefore, in addition to the effect of the configuration according to the first aspect, when correcting the exposure amount of each light output unit, the correction data generating means measures the amount of light based on the measurement data measured by the measuring means. The generated gradation correction data is generated for each gradation, and the interpolation means generates the non-measured gradation correction data by interpolation based on the measured gradation correction data generated by the correction data generation means. can do.

As a result, correction data can be obtained with high accuracy for each light output unit and for each gradation. Therefore,
Even if the variation in the exposure amount between the light output units differs for each gradation, the image data can be properly corrected at the time of exposure using the correction data corresponding to the exposure gradation.

Therefore, there is an effect that shading correction can be performed with good quality in all gradations and a high quality digital print can be created. In particular,
By interpolating non-measured gradations, correction data for each gradation is set uniformly for all light output units (dots) based on correction data generated by measuring one gradation as in the past. There is an effect that a step (streak) does not occur at the resulting gradation change (change of correction data).

According to a third aspect of the present invention, as described above, in addition to the configuration of the first or second aspect,
Further, the measurement control means measures the amount of light in a light-shielded state of the light output unit.

Therefore, in addition to the effect of the configuration according to claim 1 or 2, furthermore, the measurement control means measures the light quantity in the light-shielded state of the light output section, so that the correction means measures the light quantity in the light-shielded state. The exposure amount of the light output unit can be corrected in consideration of the above.
That is, there is an effect that the measurement control unit measures the amount of leakage light of the light output unit, and the correction unit can correct the exposure amount of the light output unit in consideration of the leakage light.

Therefore, the image recording apparatus performs the shading correction with good quality at any gradation,
This produces an effect that a high-quality digital print can be created.

According to a fourth aspect of the present invention, as described above, in addition to the configuration according to any one of the first to third aspects, the exposure head further comprises: The light output units are one-dimensionally arranged in a direction perpendicular to the direction, and are for exposing the conveyed photosensitive material.

Therefore, in addition to the effect of the configuration according to any one of claims 1 to 3, when correcting the exposure amount of each light output section of the exposure head of the digital line exposure device, the measurement control means Since each light output section and the measuring means are controlled and the exposure amount of each light output section is measured for a plurality of gradations (measurement gradations), measurement data of a plurality of gradations can be collected.

Therefore, the digital line exposure device, which is the above-described image recording apparatus, can correct the exposure amount of the light output unit based on the measurement data of a plurality of gradations, so that it is corrected based on the measurement data of one gradation. As compared with the case, it is possible to perform shading correction with high quality at any gradation and to produce a high-quality digital print.

According to a fifth aspect of the present invention, as described above, in addition to the configuration according to any one of the first to fourth aspects, the light output section is a PLZT element.

Therefore, in addition to the effect of the configuration according to any one of claims 1 to 4, the PLZT element further comprises:
It has both high translucency and an electro-optic effect that the birefringence changes when a voltage is applied.For example, it has excellent exposure capability compared to light-emitting diodes, liquid crystals, fluorescent display tubes, etc. By configuring the head with the PLZT element, there is an effect that high-definition dots can be reliably formed.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration for correcting an exposure amount in a control unit provided in the image recording apparatus illustrated in FIG. 2;

FIG. 2 is a schematic configuration diagram illustrating an overall configuration of an image recording apparatus according to an embodiment of the present invention.

FIG. 3 is an explanatory diagram illustrating a method of generating correction data by a control unit illustrated in FIG. 1;

FIG. 4 is an explanatory diagram showing a waveform of a driving voltage applied to a light output unit of an exposure head in the image recording apparatus shown in FIG.

FIG. 5 is an explanatory diagram showing a waveform of a driving voltage applied to a light output unit of an exposure head in the image recording apparatus shown in FIG.

[Explanation of symbols]

 12 Sensor (measurement unit) 21 Measurement control unit (measurement control unit) 22 Correction data calculation unit (correction data generation unit) 23 Interpolation calculation unit (interpolation unit) 25 Exposure data output unit (correction unit)

Continued on the front page F term (reference) 2H106 AA22 AA76 BH00 2H110 AB09 AC00 BA13 BA19 CD07 CD17 5B057 AA11 BA25 CB08 CD06 CE11 CH01 DB09 5C074 AA02 AA05 BB05 BB22 CC26 DD03 DD07 EE02

Claims (5)

[Claims] 1. An image recording apparatus for recording an image on a photosensitive material by controlling each light output portion of an exposure head according to image data to control a light transmission state. Measuring means for measuring the amount of exposure, and correcting means for correcting the amount of exposure of the light output unit based on the measurement data measured by the measuring means. An image recording apparatus comprising: a measurement control unit that controls each of the light output units and the measurement unit so as to measure the gradation of the image. 2. A correction data generating means for generating, for each gradation, correction data for correcting an exposure amount of the light output section at a measured gradation based on the measurement data measured by the measuring means; Interpolation means for performing an interpolation operation on the basis of the measured gradation correction data generated by the data generation means to generate correction data for correcting the exposure amount of the light output unit at the gradation not measured. The image recording apparatus according to claim 1, further comprising: 3. The image recording apparatus according to claim 1, wherein said measurement control means measures the amount of light in a light-shielded state of said light output section. 4. The exposure head according to claim 1, wherein the light output portions are one-dimensionally arranged in a direction orthogonal to a direction in which the photosensitive material is transported, and the exposure head exposes the transported photosensitive material. Item 4. The image recording apparatus according to any one of Items 1 to 3. 5. The image recording apparatus according to claim 1, wherein said light output section is a PLZT element.