JPH02277039A - Image forming device - Google Patents

Abstract

PURPOSE:To always form a stable image with adjusted color balance by discriminating whether the original image is a photographic original or a printed original and carrying out image formation responding to the type of image in a sub exposure mode or a standard mode. CONSTITUTION:This image forming device is provided with gradation adjusting function of image formed by the sub exposure, and arbitrary selection can be made between a standard mode where a normal image formation is carried out and the sub exposure mode where the sub exposure is carried out. Then the types of originals are discriminated to the printed original and the photographic original at least, and image formation can be carried out under the most appropriate image forming conditions, for example responding to each mode and type of original. As to the discrimination of originals, by carrying out discriminating function where two types of sensors which have as the sensibility peeks differing wave lengths within the wave length area of each primary color light for each of the three primary colors, R, G, and B, to measure the light of reflecting light from the original, utilizing a total of six types of measuring values as parameter, the printed original and the photographic original can be discriminated at a very high accuracy.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to an image forming apparatus capable of adjusting gradation by sub-exposure.

<Prior Art> In various image forming apparatuses, gradation adjustment is performed as one method of adjusting the image quality of images to be formed.

The gradation can be adjusted by adjusting exposure conditions such as the light intensity of the exposure light source and exposure time, by adjusting development conditions such as development temperature and development time, and by inserting various filters into the exposure optical path. Although methods such as changing the photosensitive material are known, a method using sub-exposure is often used due to the cost of the image forming apparatus, workability, etc.

As a method for adjusting the gradation of an image formed by sub-exposure, for example, in the case of a copying machine that uses direct exposure, a gray (achromatic color) reflector for sub-exposure is installed near the document table, and the gradation of the image is adjusted before or after main exposure. The light source for exposure irradiates this sub-exposure reflecting plate, and the reflected light illuminates the photosensitive material at 1150 to 1/1 of the main exposure.
This is done by exposing at a light intensity of 0.00.

By performing such sub-exposure before or after the main exposure, it is possible to soften the gradation of the formed image.

For example, when a copy image of a photographic original is formed using a photosensitive material most suitable for copying a printed original (high-contrast photosensitive material), halftones are usually not well reproduced, resulting in a hard image. However, by lowering the γ characteristic of the photosensitive material through sub-exposure, it becomes possible to reproduce the image of the photographic original well, including the intermediate tones. Further, when forming a copy image of a printed original, it is possible to form an image with a soft tone according to preference.

<Problems to be Solved by the Invention> Incidentally, in order to form good color images in various image forming apparatuses, it is necessary to improve the color balance and density balance of the images to be formed.

In such image forming devices, especially copying devices, photographs and printed matter are often used as original documents, but photographs and printed matter differ in coloring material, visibility, and spectral sensitivity of the copying material, so they cannot be used under the same conditions. If the image is copied, the resulting image will have a different color balance.

For example, in a printed document, the spectral density distributions of magenta ink and cyan ink largely overlap. For this reason, the printed original has a high magenta density, and therefore, in an image forming apparatus that is adjusted so that the printed original can be finished well, the image forming conditions are such that the magenta density is suppressed. Therefore,
If an image is formed on a photographic original under these image forming conditions, an image with a greenish tinge due to lack of magenta will be formed.

In addition, since the gradation of the original image differs between printed originals and photographic originals, copying devices that use various types of photosensitive materials such as silver halide photosensitive materials, for example, copy photo originals using high-contrast photosensitive materials. As mentioned above, this results in a hard image in which halftones are not well reproduced.

Therefore, in order to obtain a good image according to the type of original in a second image forming apparatus, it is necessary to determine the type of original and adjust the image forming conditions (color filter adjustment amount, exposure amount, etc.) according to the type of original. It is necessary to select a photosensitive material.

However, when copying, etc., the document type must be determined each time.
Not only is it troublesome for an operator to perform this visually, but it also lacks accuracy, as operators without specialized knowledge may find it difficult to distinguish between printed matter and photographs due to recent advances in printing technology.

In particular, when adjusting the gradation of the formed image during sub-exposure as mentioned earlier, it is necessary to accurately distinguish the four types of original IF and form the image under conditions appropriate to the original. The resulting image will be out of color balance, and not only will it be impossible to form a good image, but also an image that is completely different from the intended image may be formed.

For example, when using a high-contrast photosensitive material as described above and adjusting the gradation during sub-exposure to form a copy image of a photographic original, if you mistake the photographic original for a printed original, the above-mentioned problem will occur. In this case, an image with a greenish tinge is simply formed due to a lack of magenta, resulting in an image with out of color balance.

An object of the present invention is to solve the above-mentioned problems of the prior art, and when forming an image, there are two modes: a sub-exposure mode in which gradation is adjusted by sub-exposure, and a standard mode in which normal image formation is performed without sub-exposure. It is possible to make selections, and it is possible to distinguish the original into at least a photographic original or a printed original, and when selecting either sub-exposure mode or standard mode, the optimum conditions are set depending on the type of original. An object of the present invention is to provide an image forming apparatus that can perform image formation.

Means for Solving the Problems> In order to achieve the above object, the present invention has a gradation adjustment function of a formed image by sub-exposure, and provides a sub-exposure mode in which sub-exposure is performed and a standard mode in which sub-exposure is not performed. The image forming apparatus is characterized in that the document type of the formed image is determined to be at least a photographic document or a print document, and in the sub-exposure mode and the standard mode, the document type is selected according to the document type. An image forming apparatus is provided, which is characterized in that it performs image formation.

In addition, standard conditions are set for both the standard mode and sub-exposure mode, and the standard conditions for the standard mode are set so that print documents can be formed properly, and the standard conditions for the sub-exposure mode are set so that photo documents can be formed properly. Preferably.

In addition, the above-mentioned document type is determined by one color for each of the three primary colors.
It is preferable to measure the reflected light of the original using two types of sensors that have sensitivity peaks at different wavelengths within the wavelength range of the two primary color lights, and use a discriminant function that uses these six types of measured values as parameters. .

Further, it is preferable that the discriminant calculation of the discriminant function for the document type discrimination is performed by excluding the measured values below a predetermined low level and/or above a predetermined high level from the measured values.

<Operation of the Invention> The image forming apparatus of the present invention is an image forming apparatus having a function of adjusting the gradation of formed images by sub-exposure, and has a standard mode in which normal image formation is performed and gradation adjustment by sub-exposure. The sub-exposure mode can be arbitrarily selected.

Further, it is possible to discriminate the type of original document into at least a print original or a photographic original, and form an image under optimal image forming conditions according to each mode and the type of original described above.

Therefore, it is possible to adjust the gradation of the image to be formed as necessary, and for example, when forming an image of a photographic original using a high-contrast photosensitive material, it is possible to form a good image with suitably reproduced intermediate tones. Moreover, no matter what the original image is, it can be formed as a soft image.

Also, when image formation is performed in any mode,
Since the document type is determined and image formation is performed under conditions suitable for that type, an image with suitably adjusted color balance can always be stably formed.

Preferably, the type of the original is determined by using two types of sensors that have sensitivity peaks at different wavelengths within the wavelength range of each primary color light for each of the three primary colors, such as R-G-B. By photometering the reflected light and using a discriminant function that uses these six types of measured values as a parameter, it is possible to distinguish between a printed original and a photographic original with extremely high accuracy. Therefore, when forming an image in either the standard mode or the sub-exposure mode, the image can be created with the color balance adjusted appropriately under the conditions according to the document type.
It can always be formed stably.

Preferably, the discriminant calculation of the discriminant function for discriminating the document type is performed by excluding from the measured values the measured values below a predetermined low level and/or above a predetermined high level.
Even when the original is small, thick like a book, or has uneven surfaces, it is possible to always accurately identify the original type, and the original can be detected more stably. It becomes possible to perform image formation under conditions depending on the species.

<Embodiments> Hereinafter, an image forming apparatus according to the present invention will be described in detail based on preferred embodiments shown in the accompanying drawings.

The image forming apparatus of the present invention can select an image forming mode between a sub-exposure mode in which the gradation of an image to be formed is adjusted by performing sub-exposure, and a standard mode in which normal image formation is performed without sub-exposure. An image forming apparatus that, when forming an image in any mode, distinguishes the original type into at least a photographic original or a printed original, and performs image formation under optimal conditions according to the original type. be.

In the image forming apparatus of the present invention, there is no particular limitation on the method for discriminating the document type into at least a print document or a photo document, and various known methods can be used. For each of the three primary color lights of red (hereinafter referred to as R), green (hereinafter referred to as G), and blue (hereinafter referred to as B),
2 with sensitivity peaks at different wavelengths within each wavelength range
It is preferable to use a method of discriminating the document into at least a photographic document or a print document based on the value of a discriminant function, particularly a linear discriminant function, using six types of measured values as parameters.

A linear discriminant function is, for example, when multiple samples belonging to each group A and B each have p characteristic values X, the discriminant rule is z-alXl"82X2".
"aIXl"..."apXp (1-1,2+...'
, p) to create a composite variable 2, and depending on the magnitude of this composite variable Z, it is determined whether the sample to be discriminated belongs to group A or group B.

Here, the coefficients al + 2 +..., ap are calculated based on the variation Sa (edge It is determined so that the ratio, SB/S, between the variation (interval variation) and the variation SW (return variation) of the A group and the B group is maximized.

FIG. 1 shows the spectral reflection density of a photographic image and a printed image with an average color distribution.

The image indicated by solid line 2 is a photographic image, and the image indicated by dotted line 3 is a printed image.

From FIG. 1, the density of the photographic image is higher in both the vicinity of 400 nm and 450 nm.

Also, the magenta dye used in photographic images is 530
There is a maximum concentration (maximum absorption wavelength) around ~560 nm,
The cyan dye has a maximum concentration near 630 nm. Furthermore, both the cyan dye and the magenta dye have a characteristic that the density decreases around this maximum absorption wavelength.

On the other hand, the magenta ink used for printed images is 57On.
The maximum density is near m, and cyan ink has a maximum density of 600 m.
The concentration is almost flat up to around 680 nm,
On the wavelength side longer than 700 nm, a sharper decrease in density is seen than in the photographic image.

Therefore, the reflected light from a large number of photographic originals and printed originals has a sensitivity characteristic such as that shown in FIG. 2, for example, which has a sensitivity peak near the wavelength that exhibits the characteristic maximum density in the wavelength range of each of the three primary color lights. By measuring the reflection density or absorption density using six types of sensors, and creating a linear discriminant function for document type discrimination based on this measurement data and using this measurement value as a parameter according to the discrimination rule described above, image formation can be performed. The type of manuscript of the target manuscript can be easily and accurately determined.

An example of a discriminant function for discriminating between a printed manuscript and a photographic manuscript, created according to the above-mentioned discriminant rules, is shown below.

The sensors used were 400 and 450 in the B light wavelength region.
sensor b having a sensitivity peak at nm, and sensor b2
, sensor g1 and sensor g2 . having sensitivity peaks at 540 and 570 nm within the G light wavelength region. There are a total of six sensors, sensor r and sensor r2, which have sensitivity peaks at 630 and 7.00 nm in the R light wavelength region.

[Discriminant function 1] Zsa, +a2*rl+a3*gl+a4*b2+a5
*R+a, *G+a, B In the above formula, when Z<0, the color original is determined to be a printed original, and when 2≧0, the color original is determined to be a photographic original.

Also, the coefficient a+%at is between the printed original and the photographic original,
The above-mentioned ratio of Sa/Sw was determined to be the thickest, and al ” 14.33; a2 = −0, 11;
a 3- 0, 37; a a = 0
, 45:11s: 1.19; a6=
−0,67; a, = −0,96; Also, R%G and B are rl-r2, respectively.
, g2-gl and b2-bl.

It is preferable that the measured values applied to the discriminant operation of such a discriminant function exclude measured values below a predetermined low level and/or above a predetermined high level.

The documents on which images are formed are not limited to standard sizes, but can also be of various shapes and sizes, such as non-standard documents, documents smaller than the photometric area of the image forming device, thick documents, and documents with uneven surfaces. It is something that you have.

Therefore, when measuring the reflected light of these originals using a document holder with a white holding surface, if the original is small, the reflected light from the white surface of the holding surface will be measured. is photometered, resulting in a very low photometric density. Additionally, if the document is thick or uneven, such as a book, a shadow will appear in the image forming area, and no light will be reflected, resulting in a very high photometric density. It ends up.

Therefore, by determining the type of document based on the photometric value excluding the reflected light from the document holder and the photometric result from the shadowed area, very accurate document type determination can be performed.

In the image forming apparatus of the present invention, the document type discrimination is preferably carried out as described above.
334284 and Japanese Patent Application No. 1-40007.

The image forming apparatus according to M.K. and Ming. can select the image forming mode between the sub-exposure mode and the standard mode. Preferably, the four types of Ij; The image forming apparatus is configured to perform image formation under optimal conditions.

As mentioned above, such image forming devices, especially copying devices, often use photographs and printed matter as original documents, but photographs and printed matter differ in coloring materials, visual sensitivity, and spectral sensitivity of the copying material. If copies are made under the same conditions, the images will have different color balances.

Therefore, in order to form a good image with well-adjusted color balance in both sub-exposure mode and standard mode, it is necessary to set the optimal conditions according to the image forming mode and document type. It is necessary to perform image formation.

Table 1 below shows a preferred example of image forming conditions applied to the image forming apparatus of the present invention. The image forming conditions shown in Table 1 are examples in which a high-contrast photosensitive material is used.

Table 1 In the example shown in Table 1, standard condition A is a condition under which an image of a printed document is properly formed, and standard condition B is a condition under which an image of a photographic document is properly formed.

In the image forming apparatus of the present invention to which the image forming conditions shown in Table 1 are applied, when the operator selects the standard mode of the image forming mode, the standard condition A is selected as the image forming condition.

Next, by pre-scanning or the like, the document type of the document image is determined by, for example, the method described above.

Here, when the original is a print original, image formation is performed under the standard condition A, and when the original is a photographic original, the amount of yellow filter inserted is reduced and the amount of light is is reduced, and the image forming conditions are corrected from the standard condition A.

On the other hand, when the operator selects the sub-exposure mode, standard condition B is selected as the image forming condition.

Next, the document type of the document image is determined by prescanning or the like in the same manner, and if the document is a photo document,
Image formation is performed under standard condition B, and when the original is to be printed, the amount of cyan filter inserted is increased.
Image forming conditions are corrected from standard conditions B.

Note that each standard condition may be determined as appropriate depending on the applied photosensitive material, development conditions, and image forming apparatus, and may be changed or set sequentially depending on the characteristics of the photosensitive material such as manufacturing lot, the status of the developing device, etc. You may.

Further, the settings of the image forming conditions are not limited to those described above; for example, the standard conditions of the standard mode and the sub-exposure mode may be set so that the image of the printed document is properly formed; The standard conditions for both image forming modes may be set so that images of photographic originals can be formed appropriately. Furthermore, completely different image forming conditions may be set depending on the image forming mode and document type.

FIG. 3 shows the image forming apparatus of the present invention as a recording material.
An example of application to a copying apparatus using a photosensitive material A that requires a heat development step and transfers an image to an image-receiving material having an image-receiving layer in the presence of an image-forming solvent such as water is shown.

The copying apparatus 10 shown in FIG.
Photosensitive material/image receiving material supply section 16 arranged on the side of 2
(hereinafter referred to as the supply section 16); a thermal development transfer section 18 disposed on the opposite side of the supply section 16 of the housing 12;
It is comprised of a water application section 20 disposed between the supply section 16 and the thermal development transfer section 18 .

As described above, the copying apparatus 10 according to the present invention is capable of selecting the standard mode and the sub-exposure mode as the image forming mode, and also allows the document discriminating device 73 disposed in the exposure device 14 to detect the document. It distinguishes between at least a print original and a photographic original, and performs image formation under conditions according to the image forming mode and type of the original.

The supply unit 16 is configured to deliver and load a photosensitive material magazine 22 that stores the photosensitive material A in a wound manner and an image receiving material magazine 24 that stores the image receiving material C in a wound manner. Material magazine 24 and housing 1
2 (on the front side in the figure in the direction perpendicular to the conveying direction of the photosensitive material A).

Further, the photosensitive material magazine 22 is configured to be completely shielded from light when housed in the housing 12, so that the photosensitive material A is not inadvertently exposed.

Photosensitive material A requires a heat development process as described above, and an image is transferred and formed on an image receiving material having an image receiving layer in the presence of an image forming solvent such as water. , a binder, a dye-donating substance, a reducing agent, etc. In the copying apparatus 10, the photosensitive material A is wound so that its photosensitive surface faces downward, and is stored in the photosensitive material magazine 22.

The image-receiving material C is formed by coating a dye-fixing material containing a mordant on a support. The image receiving material C is
The dimension in the direction perpendicular to the conveying direction (hereinafter referred to as the width direction) is smaller than that of the photosensitive material A, and it is wound so that the image forming surface is the upper surface, and the image receiving material magazine 24
It is stored in.

A pair of pull-out rollers 26 and 28 are arranged in front of the photosensitive material magazine 22 and the image-receiving material magazine 24, respectively, and cutters 30 and 32, respectively, are arranged in front of the pull-out roller pairs 26 and 28, respectively.
is placed.

Both the photosensitive material A and the image-receiving material C are drawn out by a pair of drawing rollers 26 and 28 corresponding to each other, and cut into predetermined lengths by cutters 30 and 32.

Here, in order to facilitate peeling after the subsequent thermal development transfer,
The image-receiving material C is cut to be somewhat shorter than the photosensitive material A.

The pull-out roller pair 26 corresponding to the photosensitive material A is connected to the cutter 3.
After the zero operation, the tip is reversed to a position where the tip of the photosensitive material A is slightly pinched, and the tip of the photosensitive material A is unnecessarily exposed and deteriorated. prevent this from happening. Further, the pair of pull-out rollers 28 corresponding to the image-receiving material C releases the grip of the image-receiving material C after the cutter 32 is operated, thereby preventing damage to the leading end of the image-receiving material C.

At the rear of the cutter 30 (hereinafter, the rear means the downstream side in the conveyance direction of the photosensitive material A and the image receiving material C), an exposure section 34 is provided.
However, an inversion section 36 is arranged behind it.

The photosensitive material A, which has been pulled out by the pull-out roller pair 26 and cut into a predetermined length by the cutter 30, passes through the exposure section 34 and is turned upside down at the inversion section 36, and then returns to the exposure section 3.
4 and exposed by an exposure device 14, which will be described later.

The exposure section 34 includes a pair of conveyance rollers 38 and 40, an exposure surface glass 41 that defines a conveyance path for the photosensitive material A disposed between the pair of conveyance rollers 38 and 40, and a surface glass 41 for exposing the photosensitive material A to the exposure surface glass 41. It is composed of a pressing plate 43 for pressing.

In other words, the photosensitive material A is conveyed by a pair of conveying rollers 38 and 40 while being held between the exposure glass 41 and the pressing plate 43, and is conveyed to the reversing section 36, and at the reversing section 36, the photosensitive surface is The exposure section 34 is turned over again so that
is transported to the exposure apparatus 1, which will be described later, while being transported in the same manner.
Scanning exposure is performed at step 4.

The pair of conveyance rollers 38 and 40 are configured to be able to be reversed by various known means in order to perform sub-exposure for gradation adjustment.

The reversing unit 36 includes a branching guide 42 that branches the conveying path of the photosensitive material A vertically, and a branching guide 42 that branches the conveying path of the photosensitive material A into the vertical direction.
It is composed of a flapper 44 that defines a conveyance path for the photosensitive material A, a pair of conveyance rollers 46a and 46b, and a guide 48 that defines a reversal conveyance path for the photosensitive material A.

When the photosensitive material A is conveyed past the exposure section 34, the flapper 44 first acts on the path below the branching guide 42 and guides the photosensitive material A to the path above the branching guide 42.

The photosensitive material A conveyed above the branching guide 42 is turned upside down by the guide guide 48 and conveyed by the conveying rollers 46a and 46b, and is returned from the path below the branching guide 42 with the photosensitive surface facing upward. It is transported to the exposure section 34. In this case, the flapper 44 is connected to the branch guide 42.
It acts on the upper path and opens the lower path of the branch guide 42.

The upper part of such an exposure section 34, that is, the housing 12
An exposure device 14 is arranged above.

On the upper surface of the housing 12 of the copying apparatus 10, a document table 52 made of transparent glass or the like for placing a document 50 and a document table cover 54 for fixing the document 50 to the document table 52 are arranged.

The supply unit 16 side of the document table 52 (hereinafter referred to as the right side)
A sub-exposure reflecting plate (hereinafter referred to as a reflecting plate) 56 of an achromatic color such as gray is arranged on the side of the substrate.

Further, a cooling fan 78 is arranged below the reflection plate 56.

The reflecting plate 56 is used to reduce the amount of reflected light to about 1150 to 1/100 when irradiated by a light source 60 (described later) during sub-exposure for adjusting the gradation of the image to be formed. It is an achromatic reflective plate such as.

Furthermore, a white reference plate 58 for white balance adjustment is arranged on the left side of the document table 520 and the reflection plate 56.

A light source unit that is integrally configured with a light source 60 for exposure, a reflector 60a, and a mirror 62 is arranged below the document table 52.

This light source unit moves on the lower surface of the document table 52 in the scanning direction indicated by arrow a, and illuminates the document 50 with the light source 60 . Furthermore, during sub-exposure and white balance adjustment, the reflecting plate 56 and the white reference plate 58 are configured to be movable to positions where they can be irradiated.

As the light source 60, any light source that can be used as an exposure light source for a normal copying machine, such as a halogen lamp, can be used.

The reflected light emitted by the light source 60 and reflected by the original 50 (reflector plate 56, white reference plate 58) then enters the mirror unit and is reflected along the optical path in a predetermined direction.

The mirror unit is formed by integrally constructing two mirrors 64a and 64b, and is configured to be movable in the same direction as the light source unit described above at 1/2 the speed.

A variable diaphragm 66 for adjusting the amount of light is arranged behind the mirror unit in the optical path.

The variable diaphragm 66 is used to adjust the amount of reflected light in accordance with the type of document 50, image density, image forming mode, etc. during exposure.

An example of the variable diaphragm 66 is one having the configuration shown in FIG. 4.

The variable diaphragm 66 basically consists of a plate cam 194 and a pair of diaphragm plates 196 and 198, and the plate cam 194 moves the diaphragm plates 196 and 198 toward and away from each other to advance the optical path. Adjust the amount of reflected light.

The plate cam 194 has an opening 200, and a rack 206 is formed therein, and a gear 208 is attached to the rack 206.
, 210, and a stepping motor 212 is meshed therewith. In other words, the plate cam 194 is connected to the stepping motor 21
When the stepping motor 212 rotates clockwise, it moves to the right in the figure, and when the stepping motor 212 rotates counterclockwise, it moves to the left in the figure.

Further, such a plate cam 194 has an inclined groove 202a,
202b, 204a, and 204b are formed, and each inclined groove has a pin 196a of the aperture plate 196,
196b and pins 198a and 19 of aperture plate 198
8b is inserted.

Further, the aperture plates 196 and 198 are supported by support means (not shown) so as to be movable in the vertical direction and fixed in the horizontal direction.

Therefore, in the variable diaphragm 66, when the stepping motor 212 rotates clockwise, the plate cam 194 moves rightward in the figure according to the amount of rotation of the stepping motor 212, and the diaphragm plate 196 moves into the inclined grooves 202a and 202b. The diaphragm plate 198 rises along the inclined grooves 204a and 20
4b, both diaphragm plates separate and open the optical path. Similarly, when the stepping motor 212 rotates counterclockwise, the plate cam 194 moves to the left according to the amount of rotation, and the aperture plate 194 moves along the corresponding inclined groove.
6 is lowered, the aperture plate 198 is raised and both aperture plates are close to each other,
Increase the amount of aperture in the optical path.

The illustrated copying apparatus 10 is configured such that the operator can arbitrarily adjust (multiple selections) the amount of opening of the variable aperture 66 during sub-exposure, so that a copied image with a desired gradation cannot be formed. may be done.

The amount of light is adjusted by the variable aperture 66, and the reflected light traveling along the optical path then enters the lens unit 68.

The lens unit 68 is a combination of an imaging lens for forming an image of reflected light from the original 50 onto the photosensitive material A being conveyed through the exposure section 34, and a color filter for pre-adjustment.

An example of the lens unit 68 is one having the configuration shown in FIG.

The lens unit 68 shown in FIG. 5 includes, from the front of the optical path, a lens front group 220 as an imaging lens, a first color filter plate 222, a fixed aperture 224, and a second color filter 226.
and a rear lens group 228 are arranged and configured.

The first and second color filter plates 222 and 226 are made of, for example, transparent glass plates, with a transparent central part and color filter films of different colors deposited on both sides, as shown in FIG. In the first color filter plate 22
2 has C (cyan) and Y (yellow) color filters, and the second color filter plate 226 has C (cyan) and M (magenta) color filters, respectively.

Such first and second color filter plates 222 and 2
Reference numeral 26 is for adjusting the quality of the reflected light traveling along the optical path by adjusting the amount of each color filter inserted into the optical path.

The amount of insertion of each color filter into the optical path in the first and second color filter plates 222 and 226 is adjusted by stepping motors 222a and 226a, which serve as driving sources, respectively.
gears 222b and 226b provided at the shaft ends of
2c, 226c and racks 222d, 226d provided on the first and second color filter plates 222 and 226 that mesh with the reduction gears 222c, 226c.

That is, in the illustrated example, the first color filter plate 222 moves rightward in the figure as the stepping motor 222a rotates clockwise, and the first color filter plate 222 moves to the right in the figure as the stepping motor 222a rotates clockwise.
A cyan filter C (hereinafter referred to as C filter) is inserted into the optical path according to the amount of rotation of 22a. Similarly, when the stepping motor 222a rotates counterclockwise, the first color filter plate 222 moves to the left, and the yellow filter Y (hereinafter referred to as the "Y filter") changes the light IL according to the amount of rotation of the stepping motor 222a. inserted into.

Further, the second color filter plate 226 has a stepping mode.
By rotating the filter 226a clockwise, it moves eight times to the right in the figure, and the C filter is inserted into the optical path. Similarly, as the stepping motor 226a rotates counterclockwise, the second color filter plate 226 moves to the left, and the magenta filter M (hereinafter referred to as the "M filter") changes to the optical path according to the amount of rotation of the stepping motor 226a. inserted into.

Behind the lens unit 68 in the optical path is a mirror 70a that reflects the reflected light in a predetermined direction.

70b and 70c are arranged. The reflected light traveling along the optical path is reflected by each mirror in a predetermined direction, and is imaged in the above-mentioned exposure section 34 on the photosensitive surface of the photosensitive material A, which is scanned and conveyed in synchronization with the light source unit, and is exposed to light. Expose material A.

Note that a movable mirror 74 is arranged behind the mirror 70c to switch the optical path of the reflected light between the exposure unit 34 side and the image sensor 72 side.

During normal exposure, the movable mirror 74 is moved by a known means and is retracted from the optical path, but when adjusting the white balance or pre-scanning, it is moved to the position shown in the figure and retracted from the optical path. , and the reflected light is reflected to the image sensor 72.

The image sensor 72 measures the amount and quality of reflected light during pre-scanning and white balance adjustment.

A schematic diagram of the image sensor 2 is shown in FIG.

The image sensor 72 is similar to that used in the above-mentioned [discriminant function 1], and includes a sensor 72b1 and a sensor 72b2, which have sensitivity peaks at 400 and 450 nm in the B light wavelength region. Sensor 72g and sensor 72g, which have sensitivity peaks at 540 and 570 nm: Sensor 72r1 and sensor 72r2, which have sensitivity peaks at 630 and 700 nm in the R light wavelength region, and further collect reflected light. It has a condensing lens such as a Fresnel lens for emitting light.

The measured value by the image sensor 72 is sent to the document determining section 73.

Based on the measurement value of the image sensor 72, the document discrimination unit 73
For example, the above-mentioned [discrimination function 1] is used to determine whether the original 50 is a print original or a photographic original, and the determination result is sent to the control circuit 76, and has the configuration shown in FIG.

The measured value by the image sensor 72 is sent as an output signal to the amplifier 73A, where it is amplified and then sent to the A/D converter 73.
It is converted into a concentration signal at B.

2 f! obtained for each primary color light! The concentration signal of type I is sent to the RAM 73D via the photometric data processing device 73C.

After pre-scanning, the photometric data processing device 73C
The density signal is read out from the 3D and sent to the original discrimination device 73E, and the original i type is discriminated using, for example, the above-mentioned [discrimination function 1].

The document type discrimination result by the document discrimination section 73 and the photometry data from the image sensor 72 are sent to the control circuit 76 .

The control circuit 76 controls the amount of insertion of each color filter during exposure and the amount of adjustment of the amount of light, and its LOT stores, for example, the image forming conditions shown in Table 1 above.

The control circuit 76 selects image forming conditions according to the document type determination result from the document discriminator 73 and the image forming mode, and also selects the light amount and light quality during exposure according to the photometric data from the image sensor 72. Determine the amount of adjustment and adjust the variable aperture 66
stepping motor 212 and lens unit 6
8 stepping motors 222a and 226a are driven to adjust the amount of light at the variable aperture 66 during exposure,
The insertion amount of each color filter in the lens unit 68 is adjusted.

The exposure device 14 of the copying apparatus 10 in the illustrated example is basically configured as described above. It is configured so that it can be opened with a hinge that does not close, so that internal inspections and repairs can be easily performed.

After the exposure by the exposure device 14 is completed in the exposure unit 34, the photosensitive material A on which a latent image has been formed according to the original image of the original 50 is reversed in the reversing unit 80 so that the photosensitive surface faces downward, and is transported. It is conveyed to the water application section 20 by a pair of rollers 82 and a guide roller 84 .

The water application section 20 is for applying water as an image forming solvent to the exposed photosensitive material A.

An example of the water application section 20 is shown in FIG. 8.

The water application section 20 shown in FIG. 8 has a coating tank 86, a pair of conveying rollers 88 disposed in front of the coating tank 86, a pair of squeeze rollers 90 disposed behind the coating tank 86, and a water replenishment tank 92. It is.

Further, a conveyance guide 94 for the photosensitive material A is arranged opposite to the coating tank 86 .

The photosensitive material A conveyed from the reversing section 80 is conveyed to the coating tank 86 by a pair of conveyance rollers 88, and is coated with water, which is an image forming solvent, while being conveyed between the coating tank 86 and the conveyance guide 94, and squeezed. Excess water is removed by a pair of rollers 90 and the product is transported to the next process.

A supply line 100 having a pump 96 and a filter 98 is connected to the coating tank 86 and is supplied with water from a replenishment tank 92 .

Further, a discharge line 104 having an N6T1 valve 102 is connected to the bottom of the coating tank 86, and by opening the normally closed solenoid valve 102, the water filled in the coating tank 86 is discharged to the replenishment tank 92. do.

Furthermore, the coating tank 86 has an overflow line 106.
is connected to drain excess water in the application tank 86 to the replenishment tank 92.

In addition, the discharge line! 04, overflow line 106
Both ends on the side of the replenishment tank 92 are communicated with the water tank section 108, and are connected to the water tank section 108. The replenishment tank 92 is configured to drain water through the filter 110 to the replenishment tank 92 .

Note that the image forming solvent is not limited to water, and may be a mixture of water and a low boiling point solvent such as methanol, DMF, acetone, or isobutyl ketone. Further, it is preferable that the replenishment tank 92 is provided with not only an image forming solvent but also an antifoaming agent.

A thermal development transfer section 18 is arranged behind the water application section 16 .

On the other hand, the image-receiving material C pulled out from the image-receiving material magazine 24 of the supply section and cut into a predetermined length by the cutter 32 is conveyed by a pair of conveying rollers 112 and conveyed to the thermal development transfer section 18 .

A bonding roller 114 is arranged at the entrance of the thermal development transfer section 18, and bonds the water-coated photosensitive material A and the transported image-receiving material C. Here, the photosensitive material A and the image-receiving material C are pasted together so that the photosensitive material A is approximately 5 mm in front.

Note that a registration roller 116 is arranged in front of the bonding roller 114 on the image-receiving material C conveyance path, and a sensor (not shown) detects the position of the image-receiving material C, and pastes the photosensitive material A and the image-receiving material C at a predetermined position. configured to match.

The thermal development transfer section 173 includes a heating drum 118 containing halogen lamps 118a and 118b as heat sources, and is wound and sewn around the outer peripheral surface of the heating drum 118 at an angle of about 270 degrees, and includes four belt support rollers 120a, 12
0b.

Endless belt 12 stretched at 120c and 120d
The photosensitive material A and the image receiving material C are heated in a bonded state. By this heating, the latent image on the photosensitive material A formed by exposure in the exposure section 34 described above is developed, and is transferred onto the image receiving material C to develop color.

In addition, halogen lamps 118a and 11.8 for heating
b has an output of about 400W on one side and 800W on the other.
The heating drum 118 is heated to a predetermined temperature (7
The heating drum 118 is heated by both lamps when the temperature is raised to (about 8° C.), and the heating drum 118 is heated by an 800 W halogen lamp during normal operation.

The heat development transfer section 18 includes a first peeling claw 126 and a guide roller 128 that peel the photosensitive material A from the image receiving material C and convey it to the waste tray 124, and a heating drum 11.
A second peeling claw 132 and a guide roller 134 are arranged to peel the image receiving material C from the image receiving material C and convey it to the take-out tray 130.

The photosensitive material A and the image receiving material C are heated and transferred by the heating drum 1113 and the endless belt 122.
The photosensitive material A is peeled off by the first peeling claw 126, conveyed toward the waste tray 124 by the guide roller 128, and then conveyed to the waste tray 124 by the pair of conveying rollers 136.
On the other hand, the image receiving material C remaining on the heating drum 118 is removed from the second peeling claw 13 by further rotation of the heating drum 118.
2, it is peeled off from the heating drum 118 and transferred to the guide roller 13.
4 toward the take-out tray 130, and conveyed to the take-out tray 130 by a pair of transport rollers 1.38.

Note that a cutter 140 for cutting the photosensitive material A to be discarded is disposed behind the pair of transport rollers 136, and the photosensitive material A is disposed of in the shredded state on the waste tray 124.

The operation of this copying apparatus 10 will be explained in detail below.

In the illustrated copying apparatus 10, the operator
0 on the document table 52 and close the document table cover 54, the image forming mode of the standard mode or the sub-exposure mode is selected. Here, it is assumed that the original 50 is a photographic original and that the operator has selected the sub-exposure mode.

Next, when a start switch (not shown) is pressed, the photosensitive material A is exposed to light by the pull-out roller pair 26 from the photosensitive material magazine 22 (the photosensitive material A is pulled out from the photosensitive material magazine 22, and cut into a predetermined length by the cutter 30).

The photosensitive material A cut into a predetermined length is conveyed by a pair of conveyance rollers 38 and 40 in the exposure section 34, guided by a flapper 44 to a conveyance path above the branching guide 42, and then at a reversing section 36 where the photosensitive surface is The sheet is reversely conveyed so that it is facing upward, passes through the branch guide 42, and is conveyed again to the exposure section 34 with the photosensitive surface facing upward, and waits at a predetermined position.

On the other hand, in the exposure device 14, pre-scanning of the original g450 is performed while the photosensitive material A is being transported.

In pre-scanning, first, the light source 60 is turned on and the light source unit scans the lower surface of the document table 52.The reflected light from the document 50 is reflected by a mirror unit that moves in the same direction at 1/2 the speed of the light source unit. variable slit 66 and a lens unit 6 in which no color filter is inserted.
8, is reflected by mirrors 70a, 70b, and 70c, is reflected by a reflecting mirror disposed at the position shown in the figure, and is incident on an image sensor 72, where image information of the reflected light is read.

This image information is immediately sent to the document discrimination section 73, and the type of document is discriminated.

The document type discrimination result and the photometric data from the image sensor 72 are then transferred to the control circuit 76, and first, the LUT
Image forming conditions are selected according to the image forming mode and the type of document.

Here, in this example of operation, the image forming mode is the sub-exposure mode and the original 50 is a photographic original, so the standard condition B shown in Table 1 is selected as the image forming condition. at the same time,
In the control circuit 76, the amount of light amount adjustment and the amount of pre-purchase adjustment are determined based on the photometric data from the image sensor 72.

When the pre-scan ends, the light source unit and mirror unit return to their home positions, and the photosensitive material A is transported to a predetermined position, exposure of the photosensitive material A is started in accordance with the selected image forming mode.

In this example of operation, since it is the sub-exposure mode, first,
The light source unit moves to a position where the light source 60 can illuminate the reflecting plate 56, and illuminates the reflecting plate 56.

The reflected light from the reflecting plate 56 is reflected by the mirror unit, passes through the variable diaphragm 66 and the lens unit 68, and is dimmed, and is then reflected by the mirror 70a.

70b and 70c, the photosensitive material A is held between the exposure surface glass 41 and the press plate 43, and is transported by the transport roller pair 38 and 40.
Sub-exposure is performed at a light intensity of about /100 to change the γ characteristics of the photosensitive material A.

When the sub-exposure is completed, the pair of conveying rollers 38 and 40 rotate in reverse to convey the photosensitive material to the reversing section 36.

The photosensitive material A is moved in the opposite direction until it reaches the predetermined position (in the direction of the reversal section 36)
The light source unit returns to its home position.

On the other hand, the control circuit 76 controls the standard condition B, which is the image forming condition previously selected according to the document type and the image forming mode, and the light amount adjustment amount and light quality adjustment determined from the photometric data from the image sensor 72. Depending on the amount, variable aperture 6
6 stepping motor 212 and lens unit 68
The stepping motor 222 of the first color filter plate 222 of
a and the stepping motor 226a of the second color filter plate 226 are rotated, the amount of light is adjusted using the variable diaphragm 66, each color filter is inserted into the optical path by a predetermined amount, and exposure conditions are set.

After setting the exposure conditions, main exposure is started.

In the main exposure, the light source unit scans the lower surface of the document table 52 while the light source 60 illuminates the original fA 50 .

This reflected light is reflected by the mirrors 64a and 64b of the mirror unit that moves in the same direction at 1/2 the speed of the light source unit, and is passed through the variable aperture 66 and lens unit 68, which are adjusted according to the set exposure conditions. The photosensitive material A is mainly exposed to light, which is then reflected by the mirrors 70a, 70b and 70c, is held between the exposure glass 41 and the press plate 43, and is transported by the pair of transport rollers 38 and 40. , a latent image is formed on the photosensitive material A.

When the exposure is completed, the photosensitive material A is reversely conveyed in the reversing section 80 and conveyed to the water application section 20 with the photosensitive surface facing downward.
While being transported by a pair of transport rollers 88 and a pair of squeeze rollers 90, it passes through a coating tank 86 and is coated with water, which is an image forming solvent. Note that excess water applied in the application tank 86 is removed by a pair of squeeze rollers 90.

On the other hand, the image-receiving material C is pulled out from the image-receiving material magazine 24 by a pull-out roller pair 28, cut into a predetermined length by a cutter 32, conveyed to a transport roller pair 112, and kept waiting at a predetermined position by a registration roller pair 116. It will be done.

When the photosensitive material A is conveyed to a predetermined position, the registration roller pair 116 starts conveying the image receiving material C, and the photosensitive material A and the image receiving material C are bonded together by the bonding roller 114.

The photosensitive material A and the image-receiving material C bonded by the bonding roller 114 are transferred to the heating drum 118 at the thermal development transfer section 18.
The latent image carried by the photosensitive material [A] is developed, transferred to the image receiving material C, and colored.

Next, the photosensitive material A is separated from the image receiving material C by the first peeling claw 126.
It is peeled off from the substrate, guided by a guide roller 128, conveyed by a pair of conveying rollers 136, cut into pieces by a cutter 140, and discarded in a waste tray 124. On the other hand, image receiving material C
is peeled off from the heating drum 118 by the second peeling claw 132, guided by the guide roller 134, and transferred to the conveying roller pair 138.
and is transported to the take-out tray 130.

As above, the image forming apparatus according to the present invention has been described in detail based on the preferred embodiment shown in the attached drawings, but the present invention is not limited thereto. The present invention is applicable to various image forming apparatuses, such as image forming apparatuses using wet development, image forming apparatuses using heat- and pressure-sensitive photosensitive materials, and electrophotographic image forming apparatuses.

Further, the exposure method is not limited to the light source moving type scanning exposure shown in the illustrated example, but can also be applied to document table moving type scanning exposure or surface exposure.

Further, the present invention is not limited to the above examples, and it goes without saying that various changes and improvements may be made without changing the gist of the present invention.

<Effects of the Invention> The image forming apparatus of the present invention is an image forming apparatus that can arbitrarily select between a standard mode for normal image formation and a sub-exposure mode for performing gradation adjustment using sub-exposure. It is possible to discriminate the document type into at least a print document or a photo document, and form an image under optimal image forming conditions according to each mode and document type.

Therefore, it is possible to adjust the gradation of the image to be formed as necessary, and for example, when forming an image of a photographic original using a high-contrast photosensitive material, it is possible to form a good image with suitably reproduced intermediate tones. It is also possible to form various original images as soft-toned, so-called soft images.

Also, when image formation is performed in any mode,
Since the document type is determined and image formation is performed under conditions suitable for that type, an image with suitably adjusted color balance can always be stably formed.

[Brief explanation of drawings]

FIG. 1 is a graph showing the spectral reflection density of a printed original and a photographic original. FIG. 2 is a graph showing sensitivity characteristics of a sensor applicable to the present invention. FIG. 3 is a schematic cross-sectional view of an example in which the image forming apparatus according to the present invention is applied to a copying apparatus using a photosensitive material that requires a heat development process and transfers an image to an image receiving material in the presence of an image forming solvent. It is a diagram. FIG. 4 is a schematic diagram of an example of a variable aperture applied to the copying apparatus shown in FIG. 3. FIG. 5 is a schematic diagram of an example of a lens unit applied to the copying apparatus shown in FIG. 3. FIG. 6 is a schematic diagram of an example of an image reader applied to the copying apparatus shown in FIG. 3. FIG. 7 is a schematic diagram showing the configuration of a document discriminating section applied to the copying apparatus shown in FIG. 3. FIG. 8 is a schematic diagram of an example of a water applicator applied to the copying apparatus shown in FIG. 3. Description of symbols 10... Copying device, 12... Housing, 14... Exposure device, 16... Photosensitive material/image receiving material supply section, 18... Thermal development transfer section, 20... Water coating Part, 22... Photosensitive material magazine, 24... Image receiving material magazine, 34... Exposure section, 36... Reversing section, 66... Variable aperture, 68... Lens unit, 72... Image reader 73... Original discrimination section, 76... Control circuit, 118... Heating drum, 122... Endless belt, 126... First peeling claw, 132... Second peeling claw

Claims (1)

[Claims] (1) An image forming apparatus having a gradation adjustment function of an image formed by sub-exposure and capable of selecting a sub-exposure mode in which sub-exposure is performed and a standard mode in which sub-exposure is not performed, wherein the formed image What is claimed is: 1. An image forming apparatus that discriminates document types into at least photographic documents and print documents, and performs image formation in accordance with the document types in the sub-exposure mode and the standard mode, respectively.