JP2000326554A - Image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To execute correction of pixel variation with respect to a recording element array as needed at such time as a photographic paper is replaced. SOLUTION: When a recording medium newly replaced corresponding to a detection signal indicative of a containing means 3 that contains the recording medium is different from that heretofore used, a control means 7 generates a test pattern and a density sensor 51 reads a visible image of the test pattern, then correction of a correction value is executed. As a result, when the recording medium is replaced, the correction value is corrected so as to be in conformity with the recording medium. When it is replaced with the same type of the recording medium, the correction value is not corrected. As a result, it is possible to achieve an image forming apparatus capable of executing correction of pixel variation with respect to a recording element array on an as needed basis.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to an image forming apparatus, and more particularly to an improvement in image unevenness due to light emission characteristics of a recording element of the image forming apparatus.

[0002]

2. Description of the Related Art When a latent image is formed on a photosensitive material by a plurality of recording elements (LED arrays), it is necessary to make the light emission characteristics of each recording element uniform, but in practice, the light emission characteristics are made completely the same. Cannot be performed, and variations occur.

[0003] Therefore, a test pattern signal is given to a plurality of recording elements in advance to obtain a test pattern, a visible image of the test pattern is formed on a photosensitive material, the density of the test pattern is read by a scanner or the like, and correction data for each element is read. Ask. Then, an image signal given at the time of actual image formation is corrected by the obtained correction value so as to eliminate image unevenness due to variation.

[0004]

However, when forming a latent image on a recording medium made of a photosensitive material, the characteristic of the recording medium itself is one of the causes of pixel unevenness. Therefore, when the recording medium is replaced, it is necessary to perform the pixel unevenness correction again.

However, in an actual apparatus, when a recording medium is exchanged, it cannot be determined whether the recording medium has been exchanged for a different recording medium or the same recording medium. Did not know whether to do.

Further, when a test pattern print is output, it is extremely difficult to identify individual light emitting elements based on information read from the test pattern and correct each light emitting element required.

SUMMARY OF THE INVENTION The present invention has been made in view of the above technical problems, and has as its object to provide an image forming apparatus capable of correcting pixel unevenness of a recording element array when necessary.

[0008]

That is, the present invention for solving the above problems is as described below. First
According to the invention, in an image forming apparatus for forming a visible image by a given image signal, a storage unit for storing a recording medium, and a detection signal for detecting that the storage unit has been replaced and outputting a detection signal. A detecting unit, a plurality of recording elements, a storage unit that stores correction values corresponding to each of the plurality of recording elements, a correction unit that corrects the given image signal with the correction value, and a correction unit. Driving means for driving the plurality of recording elements based on the corrected image signal to form a latent image on a recording medium, and developing means for developing the recording medium on which the latent image is formed to obtain a visible image Test pattern generating means for providing a signal for generating a test pattern to the plurality of recording elements to form a test pattern latent image on a recording medium; and the developing means provided in a recording medium transport path. Therefore, it has a reading unit for reading a test pattern visible image obtained by development, and a correcting unit for correcting the correction value based on a signal read by the reading unit. An image forming apparatus.

Further, in the first invention, there is provided control means for operating the test pattern generation means, the reading means and the correction means in response to the detection signal, and controlling the correction of the correction value. It is desirable.

In the image forming apparatus according to the first aspect of the present invention, a test pattern is generated in response to a detection signal indicating replacement of a storage unit that stores a recording medium, and a visible image of the test pattern is read to obtain a correction value. I am trying to fix it. As a result, if the recording medium is replaced,
The correction value is corrected so as to match the recording medium.

As a result, it is possible to realize an image forming apparatus capable of performing pixel unevenness correction on the recording element array when necessary. According to a second aspect, in an image forming apparatus which forms a visible image based on a given image signal, a storage unit for storing a recording medium and a detection signal is output by detecting that the storage unit has been replaced. First detecting means for detecting the information of the recording medium stored in the storage means, a plurality of recording elements, and correction data corresponding to each of the plurality of recording elements A correction means for correcting the given image signal with the correction value, and driving the plurality of recording elements based on the image signal corrected by the correction means to store a latent image on a recording medium. Driving means for forming an image, developing means for developing a recording medium on which a latent image is formed to obtain a visible image, and applying a signal for generating a test pattern to the plurality of recording elements, thereby forming a test pattern on the recording medium. Test pattern generating means for forming a latent image, reading means for reading a test pattern visible image obtained in the recording medium transport path and developed by the developing means, and read by the reading means. Correction means for correcting the correction value based on a signal.

According to the second aspect of the present invention, when the recording medium of the newly exchanged storage unit is different from the recording medium used up to that time in accordance with the detection signal of the detection unit, It is desirable to have a control means for operating the test pattern generation means, the reading means, and the correction means, and controlling the correction value to be corrected.

In the image forming apparatus according to the second aspect of the present invention, the newly replaced recording medium differs from the previously used recording medium in response to a detection signal indicating replacement of the storage unit storing the recording medium. In such a case, a correction value is corrected by generating a test pattern and reading a visible image of the test pattern.

As a result, when the recording medium is replaced, the correction value is corrected so as to match the recording medium. When the recording medium is replaced with the same recording medium, the correction value is not corrected.

As a result, it is possible to realize an image forming apparatus capable of performing pixel unevenness correction on the recording element array when necessary.

[0016]

Embodiments of the present invention will be described below in detail. <Configuration of Image Forming Apparatus> First, the overall configuration of an image forming apparatus used in the present embodiment will be described with reference to FIG.

FIG. 1 is a block diagram showing an electrical configuration of a main part of an embodiment of the present invention. FIG. 2 is a block diagram schematically showing an overall electrical configuration of the embodiment of the present invention. 3
1 is a perspective view showing an external configuration of an apparatus.

First, the overall mechanical configuration and arrangement of the apparatus will be described with reference to FIG. The image forming apparatus 1 of this embodiment includes a magazine loading section 3 on the left side of the apparatus main body 2, an exposure processing section 4 for exposing a photosensitive material as a recording medium in the apparatus main body 2, and an exposed photosensitive section. A development processing section 5 is provided for developing and drying the material to produce a print, and the produced print is discharged to a tray 6 provided on the right side of the apparatus main body 2. Further, a control unit 7 is provided inside the apparatus main body 2 at a position above the exposure processing unit 4.

A CRT display 8 is arranged above the apparatus main body 2. On the left side of the CRT display 8, a film scanner section 9 which is a transparent document reading device is arranged, and on the right side, a reflective document input device 10 is arranged.

Documents read from the film scanner unit 9 or the reflection document input device 10 include photographic photosensitive materials.
Examples of the photographic material include a color negative film and a color reversal film. The information is converted into digital information by the film scanner of the film scanner unit 9 and can be used as frame image information. When the photographic photosensitive material is color paper, frame image information can be obtained by the flatbed scanner of the reflection document input device 10.

An operation unit 11 is provided in front of the CRT display 8.
The information input means 12 is provided in the operation unit 11, and the information input means 12 is constituted by, for example, a touch panel or the like.

In the position of the control unit 7 of the apparatus main body 2,
PC card set unit 1 into which PC card 13 can be inserted
The PC card 13 has a memory in which a plurality of frame image data captured by a digital camera is stored. The PC card having a memory in which frame image data is stored in the present invention is, for example, a flash ATA card, a compact flash card connected to a PC card adapter, a smart media, or the like.

Next, the electrical configuration of the main part of the image forming apparatus 1 will be described with reference to FIGS. The control unit 7 of the image forming apparatus 1 reads document information from the film scanner unit 9 and the reflection document input device 10 based on command information from the information input unit 12, obtains image data, and displays the image data on the CRT 8. Further, a data storage unit 71 is provided. The data storage unit 71 stores and sequentially stores image data and corresponding order information (information on how many prints are to be created from which frame image, print size information, etc.). . Further, the control unit 7 also serves as a test pattern generating means for generating a test pattern and a correcting means for correcting a correction value.

A frame image from the developed negative film N is input from the film scanner unit 9, and a frame image from the print P which has been printed and developed by printing the frame image on photographic paper is input from the reflection original input device 10. Is done.

The control section 7 has an image processing section 70. The image processing section 70 performs image processing on the image data to form image data for exposure, and sends it to the exposure processing section 4. The exposure processing section 4 exposes the photosensitive material to an image from a plurality of recording elements (LED arrays), sends the photosensitive material to a development processing section 5, and the development processing section 5 develops the exposed photosensitive material. And dry to make a print.

The image forming apparatus 1 includes frame image input means 80 for inputting frame image data from a recording medium, and template storage means 81 for storing template data.
And a selection unit 82 for selecting a predetermined template stored in the template storage unit 81.

Here, the frame image input means 80 comprises a film scanner section 9, a reflection original input apparatus 10, a PC card set section 14, and the like.
Frame image data is input from a recording medium such as a P and PC card 13.

The template storage means 81 stores in advance data of at least one template for setting a background image and a composite area. The selection means 82
A predetermined template provided in the operation unit 11 is set by an operation of an operator, and a predetermined template is selected from a plurality of templates stored in the template storage unit 81 in advance. Create a print of the image data. The synthesis using the template is performed by, for example, a well-known chroma key method.

The display means A, the data storage means 71,
The template storage unit 81, the control unit 7, the film scanner unit 9, the reflection document input device 10, and the PC card set unit 14 are provided integrally with the apparatus main body 2, but at least one of them is provided separately. You may. In this case, the image forming apparatus 1 is treated as a print creation system.

A sensor 31 for determining whether or not the magazine loading unit 3 has been replaced or its type is provided on the side of the apparatus main body 2 to which the magazine loading unit 3 is attached. The sensor 31 may simply detect whether or not the magazine loading unit 3 has been replaced, or may be a sensor that can determine the type of photographic paper inside the magazine loading unit 3 and the like.

A density sensor 51 for reading a print test pattern is provided near the print output section of the development processing section 5. This density sensor 51
It is preferable that the line sensor has a resolution and a gradation characteristic capable of reading the density of each recording element on the test pattern in the vicinity of the output of the development processing unit 5.

<Operation of Image Forming Apparatus> In an image forming apparatus which performs exposure by causing an LED array to emit light in accordance with an image signal, forms a latent image on a photosensitive material, and forms an image by a developing process, For example, FIG.
As shown in (a), a plurality of LEDs (A4 vertical width: 29
(Approximately 4000 pieces per 7 mm).

Even when the same voltage is applied to each LED due to a manufacturing error, the amount of light emission is not as shown in FIG.
The variation as described in (b) occurs. This variation in the amount of light emission appears as unevenness in the image, which hinders appropriate image formation.

If the applied voltage of each LED is finely adjusted individually, it is possible to make the amount of light emitted from all the LEDs uniform. However, if the number is as large as several thousand, the circuit cost increases. In addition, since the size of the apparatus is increased due to the space of the adjustment circuit itself, the following other solution is usually adopted.

As another solution, there is a method of changing the light emission time per pixel of each LED so as to adjust the same density for each LED when viewed as the density per pixel. Be taken.

FIG. 5 illustrates a case where the density of each pixel formed by two LED-A and LED-B having different light emission amounts when the same voltage is applied is matched.

Since the light emission amount of the LED-A corresponding to the pixel A is higher than that of the LED-B corresponding to the pixel B, the pixel A has a higher density when lit at the same time width. There will be a difference.

Therefore, the LED-B corresponding to the pixel B
Is made longer than the lighting time of the LED-A corresponding to the pixel A, as a result, a method of eliminating the density difference between the pixel A and the pixel B is adopted.

The adjustment of the lighting time of each LED for eliminating the density difference in this manner is built in the control unit 7 in advance as a "correction value" at the time of shipment of the image forming apparatus. However, when a photosensitive material using silver halide grains is exposed, another problem occurs.

Since a plurality of LEDs are arranged close to each other, the emitted lights of adjacent LEDs overlap each other, but the density of the overlapped portion may differ for each photosensitive material.

That is, in the case of the photosensitive material a, the generated density is as shown by the solid line in FIG. 6A, but in the case of the other photosensitive material b, the generated density is the solid line of FIG. 6B. Becomes

The plurality of LEDs do not emit light at the same time in terms of control, but emit light sequentially in a very short time interval. Therefore, in the portion where the light emitted from the two LEDs overlaps, multiple exposure is performed, and the multiple exposure produces a multiple exposure effect in which the density simply increases or decreases more than the sum of the respective light emission amounts. Because.

Assuming that the amount of light emission required to obtain a predetermined density in one exposure is E1 and the sum of the amount of light emission required in two exposures to obtain the same density is E2, the sensitivity is increased by E1 / E2. It is known that the rate (= α) is different depending on the type of the photosensitive material.

In the case described above, the a shown in FIG.
In the case of the photosensitive material of No. 1, approximately α = 1, but in the case of the photosensitive material of B shown in FIG. 6B, α <1. A factor that may further complicate the problem is that the density is adjusted according to the lighting time within one pixel as described above.

As shown in FIG. 5, when the same voltage is applied, the relationship between the light emission time T1 of the LED-A having a large light emission amount and the light emission time T2 of the LED-B having a small light emission amount is T1.
In the case of <T2, as a result, the densities of the pixels A and B are observed in the same manner.

Here, in the case shown in FIG.
In the portion where the light emission amounts of A and LED-B overlap, the multiple exposure effect occurs as described above, and the density changes depending on the photosensitive material. However, the density appears as it is in a portion where the light emission amounts of the two LEDs do not overlap.

Therefore, when it is intended to accurately set two pixels to have the same density, how many portions where the light emission amounts of the two LEDs overlap and what the sensitivity increase rate of the photosensitive material is. You have to consider whether it is.

In an actual apparatus, it is necessary to handle a plurality of types of photosensitive materials from a plurality of photosensitive material manufacturers, and the sensitivity increase rates of the respective photosensitive materials are slightly different. However, even if all the photosensitive materials are used, in order to obtain a good image without unevenness, the lighting time of all the LEDs is controlled, and correction is made in advance so that an image without unevenness is obtained. You need to find the value.

Therefore, in the present embodiment, each time a new photosensitive material is loaded, exposure is once performed using a pre-stored image for detecting a correction value, development processing is performed, and image density is determined. Measure the density of the photosensitive material that has become observable, and use the measured density difference for each pixel or LED.
The correction value of each correction value is obtained.

Thus, even if photosensitive materials having different rates of increase in sensitivity are loaded, the initial correction value is corrected in accordance with the printing paper so that a good image without unevenness can be obtained in advance. It becomes possible to do.

Even when the recording medium is replaced, if the recording medium is replaced with the same recording medium as the original, it is not necessary to perform the pixel unevenness correction again. (The maker name, lot number, and the like are provided by the order of the protrusions, bar codes, IC chips, and the like) are obtained by the sensor 31, and the recording medium used up to the previous time differs from the recording medium newly replaced this time. The control unit 7 controls so as to perform the pixel unevenness correction only at the time.

That is, when replacing the magazine loading unit 3 which is a storage unit storing the photographic paper 42 as a recording medium, the newly exchanged recording medium is used up to that time in accordance with a detection signal from the sensor 31. If it is different from the recording medium, the control unit 7 generates a test pattern, causes the exposure processing unit 4 to expose the test pattern, and develops the test pattern in the developing unit 5 to print a visible image. You. Then, the print P0 (see FIG. 2) of the test pattern is read by the density sensor 51, and the read result is fed back to the control unit 7. And
The control unit 7 refers to the read result of the test pattern,
The correction value is corrected.

As a result, when the photographic paper is replaced (when the magazine loading unit 3 is replaced), the correction value is corrected so as to match the photographic paper. Note that the sensor 31 may be simplified, and the correction value may be corrected by always creating and reading a test print when the magazine loading unit 3 is replaced. On the other hand, if the sensor 31 reads the information of the photographic paper in the magazine loading unit 3 and it is determined that the photographic paper is replaced by the same photographic paper by the detection signal of the sensor 31, the above correction is performed. The value may not be modified. As a result, it is possible to realize an image forming apparatus capable of automatically performing pixel unevenness correction on a print element array when necessary.

In this embodiment, the image forming apparatus 1 performs printing by a digital printer. However, the present invention can be similarly applied to a printer using an optical exposure system (such as a conventional minilab).

[0055]

In the image forming apparatus according to the first aspect of the present invention, in response to a detection signal indicating replacement of a storage unit storing a recording medium,
A correction value is corrected by generating a test pattern and reading a visible image of the test pattern. As a result, when the recording medium is replaced, the correction value is corrected so as to match the recording medium. As a result, it is possible to realize an image forming apparatus that can perform pixel unevenness correction on the recording element array when necessary.

In the image forming apparatus according to the second aspect of the present invention, when the newly replaced recording medium is different from the previously used recording medium in response to the detection signal indicating the replacement of the storage unit storing the recording medium. Then, a correction value is corrected by generating a test pattern and reading a visible image of the test pattern. As a result, when the recording medium is replaced, the correction value is corrected so as to match the recording medium. When the recording medium is replaced with the same recording medium, the correction value is not corrected. As a result, it is possible to realize an image forming apparatus that can perform pixel unevenness correction on the recording element array when necessary.

[Brief description of the drawings]

FIG. 1 is a functional block diagram illustrating a configuration of an image forming apparatus used in an embodiment of the present invention.

FIG. 2 is a functional block diagram illustrating a configuration of an image forming apparatus used in an embodiment of the present invention.

FIG. 3 is a perspective view illustrating an external configuration of an image forming apparatus used in the embodiment of the present invention.

FIG. 4 is an explanatory diagram showing a recording element used in the image forming apparatus according to the embodiment of the present invention and a state of light emission unevenness.

FIG. 5 is an explanatory diagram illustrating a recording element used in the image forming apparatus according to the embodiment of the present invention and a state of correcting light emission unevenness.

FIG. 6 is an explanatory diagram showing a result obtained on different photographic paper due to correction of a recording element used in the image forming apparatus according to the embodiment of the present invention and light emission unevenness.

[Explanation of symbols]

 Reference Signs List 1 image forming apparatus 2 apparatus main body 3 magazine loading section 4 exposure processing section 5 development processing section 6 tray 7 control section 8 CRT display section 9 scanner 31 sensor 51 density sensor

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2C061 AS11 KK04 KK18 KK25 KK28 KK33 2C162 AE05 AE12 AE23 AE28 AE47 AE77 AF13 AF23 AF72 AF83 FA04 FA17 5C074 AA07 AA09 BB04 BB06 BB22 BB23 DD03 DD11 DD19 GG08

Claims (4)

[Claims] 1. An image forming apparatus for forming a visible image based on a given image signal, comprising: storage means for storing a recording medium; and detecting that the storage means has been exchanged and outputting a detection signal. Detecting means, a plurality of printing elements, a storage means for storing correction values corresponding to each of the plurality of printing elements, a correcting means for correcting the given image signal with the correction values, and a correcting means Driving means for driving the plurality of recording elements based on the image signal corrected by the method to form a latent image on a recording medium, and developing the recording medium on which the latent image is formed to obtain a visible image Means for providing a signal for generating a test pattern to the plurality of recording elements to form a test pattern latent image on a recording medium; and A reading unit for reading a test pattern visible image obtained by developing by a developing unit; and a correcting unit for correcting the correction value based on a signal read by the reading unit. Image forming apparatus. 2. A control means for operating the test pattern generating means, the reading means and the correcting means in accordance with the detection signal, and controlling the correction value to be corrected.
The image forming apparatus according to claim 1, wherein: 3. An image forming apparatus for forming a visible image based on a given image signal, comprising: storage means for storing a recording medium; and detecting that the storage means has been exchanged and outputting a detection signal. First detecting means, second detecting means for detecting information of the recording medium stored in the storage means, a plurality of recording elements, and correction data corresponding to each of the plurality of recording elements. Storage means for storing; a correction means for correcting the given image signal with the correction value; a latent image on a recording medium by driving the plurality of recording elements based on the image signal corrected by the correction means A developing means for developing a recording medium on which a latent image is formed to obtain a visible image, and applying a signal for generating a test pattern to the plurality of recording elements to perform a test on the recording medium. Test pattern generating means for forming a turn latent image; reading means provided in a recording medium transport path for reading a test pattern visible image obtained by being developed by the developing means; and read by the reading means. Correction means for correcting the correction value based on a signal. 4. The test pattern generating means and the reading means when a recording medium of a newly exchanged storage means is different from a recording medium used up to that time in accordance with a detection signal from the detection means for the detection. And operating the correction means,
The image forming apparatus according to claim 3, further comprising a control unit configured to perform control so as to correct the correction value.