JP3508601B2 - Photo printing equipment - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photographic printing apparatus for printing an image on a photosensitive material using, for example, a DMD (Digital Micromirror Device).
In particular, the present invention relates to a photographic printing apparatus capable of producing a sufficient density even when a light-sensitive material having low sensitivity is used.

[0002]

2. Description of the Related Art Conventionally, an image recorded on a film is read as image data, and each pixel of a light modulation element is driven according to the read image data to control the exposure of the printing paper to form an image on the printing paper. There have been proposed various so-called digital exposure type photographic printing apparatuses for printing.
For example, FIG. 4 shows the structure of a photographic printing apparatus in the case where the above-mentioned light modulation element is composed of a DMD. As shown in this figure, this type of photographic printing apparatus includes a light source 51, a color wheel 52, an integrator 53, a DMD 54, and a printing lens 55.

The light source 51 is composed of, for example, a halogen lamp. The color wheel 52 is shown in FIGS.
As shown in, the substantially fan-shaped R (red), G (green), G
The (blue) filters 52R, 52G, and 52B are arranged in parallel, and the light from the light source 51 is filtered by the filters 52R, 52G, and 52R.
52B so that it can pass through any area of the rotary shaft 5
It is designed to rotate around 2a. Filter 52
R and filter 52G, filter 52G and filter 52
B, the filter 52B and the filter 52R are the spokes 5
2b are connected to each other. The integrator 53 diffuses the light transmitted through the color wheel 52 and supplies uniform light to the DMD 54. The printing lens 55 is a lens for forming an image of the reflected light from the DMD 54 on the photographic paper 56 at a predetermined magnification.

As shown in FIG. 6, the DMD 54 has microscopic swingable micromirrors 54a (hereinafter simply referred to as mirrors) 54a arranged in a plane, for example, in 1024 rows and 1280 columns. . Therefore, about 1 in total
This means that 310,000 mirrors 54a are arranged.
Each mirror 54a is fixed to a substrate (not shown) via a post (not shown), and the tilt of each mirror 54a is adjusted according to an image signal to change the reflection direction of the light from the light source 51. By changing it, the exposure of the photographic printing paper 56 is controlled.

With such a configuration, the light emitted from the light source 51 is transmitted through the color wheel 52, for example, the filter 52.
DM through the R, diffused by the integrator 53
It is incident on 54.

In the DMD 54, the tilt of each mirror 54a is adjusted according to the image signal as described above. That is, the tilt of the mirror 54a corresponding to the pixel to be exposed on the photographic paper 56 is adjusted so that the incident light is reflected by the mirror 54a in the direction toward the photographic paper 56 (the mirror 54a is turned ON). ). On the other hand, photographic paper 5
The mirrors 54a corresponding to the six pixels to be exposed are
The inclination of the incident light is adjusted so that the incident light is reflected off the optical path toward the printing paper 56 by the mirror 54a (the mirror 54a is turned off).

Therefore, only the light incident on the mirror 54a which is turned on is applied to the printing paper 56 through the mirror 54a and the printing lens 55. On the other hand, the light incident on the mirror 54a which is turned off is
Is reflected in a direction out of the optical path to the photographic paper 56 and does not reach the photographic paper 56. Each such mirror 5
The ON / OFF control of 4a is similarly performed at the time of exposure by the light passing through the filters 52G and 52B,
Finally, a color image corresponding to the image signal is printed on the photographic printing paper 56.

By the way, the photographic paper 56 is produced by using the DMD 54.
In addition to the exposure method that uses the entire mirror 54a of the DMD 54 as described above, there is a method called a scanning exposure method. This scanning exposure method is, for example, 192 rows vertically and 1 horizontally on the light reflecting surface of the DMD 54 of FIG.
Using only the 280 rows of mirrors 54a (the mirrors 54a in the regions 54P shown by the shaded areas in the figure), for example Spread L
This is a method in which the photographic printing paper 56 is conveyed and exposed simultaneously based on an exposure algorithm called UT or Super Spread LUT.

Here, the Spread LUT is the color wheel 5
This is an algorithm for performing exposure while the photographic printing paper 56 is conveyed by an amount corresponding to 192 rows of the mirror 54a while one rotation of 2 is performed. Therefore, as shown in FIG.
92 rows divided into three equal parts, that is, 64 rows of the mirror 54a,
Each is subjected to R, G, and B exposure for a predetermined pixel of the printing paper 56. On the other hand, the Super Spread LUT is an algorithm for performing exposure while conveying the photographic printing paper 56 by an amount corresponding to 192 rows of the mirror 54a while the color wheel 52 makes four rotations. In this case, as shown in FIG. 7B, while the color wheel 52 makes one rotation, the photographic printing paper 56 is conveyed by an amount corresponding to 48 rows of the mirror 54a, and each rotation of the color wheel 52 is performed. At 48, the mirror 54a is divided into three equal parts of 48 lines, that is, 16 lines.
Are subjected to R, G, and B exposures on predetermined pixels of the printing paper 56, respectively. Therefore, if the conveyance speeds of the photographic paper 56 are the same, the Sp
Faster than rotation speed in read LUT (eg 3200 rp)
The color wheel 52 will rotate (in m).

By the way, since the light source 51 of the photographic printing apparatus is composed of the halogen lamp as described above, the DMD is used.
Irregularity of the illuminance due to the halogen lamp is inevitably generated on 54. Such illuminance unevenness is not a problem when a black image is printed on the photographic printing paper 56, but tends to appear as density unevenness when a halftone image is printed.

When there is uneven illuminance on the DMD 54, the farther the distance between the mirrors 54a used when printing a color image is between colors, the more uneven the density appears on the photographic paper 56, but with the Super Spread LUT. , The distance between the colors of the mirror 54a used for exposing a predetermined pixel of the photographic paper 56 is smaller than that in the case where the Spread LUT is used.
There is an advantage that density unevenness can be suppressed as compared with the case of using the read LUT. Therefore, in recent years, Super
The scanning exposure method based on the exposure algorithm of Spread LUT is often used.

By the way, in the exposure algorithm of the Super Spread LUT, each mirror 54a is driven by, for example, 5%.
It is performed with four kinds of duty of 5.4%, 6.25%, and 25%. Note that the above-mentioned duty means that the mirror 54a is used during the time from the exposure of a predetermined pixel of the photographic paper 56 to the exposure of the next pixel, that is, the time required to convey one pixel of the photographic paper 56. It is a ratio of the ON time. For example, if the movement time of one pixel of the printing paper 56 (printing paper transport time) is 400 μsec and the mirror 54a is ON for 100 μsec, the duty is 25%.

Further, in Super Spread LUT, in order to realize 4096 gradations in 12 bits, 5%, 5.4%,
For example, each of the mirrors 54a driven at a duty of 6.25% and 25% is used, for example, 4, 2, 3, and 55, for a total of 64 mirrors. One dot (pixel) is formed by performing exposure with the combination of the mirrors 54a. Hereinafter, this exposure principle will be described with reference to FIGS.

FIGS. 5A and 5B show a color wheel 52.
The duty of the mirror 54a that is driven when the light transmitted through the predetermined area is guided to the photographic printing paper 56 is shown for each transmission area. It should be noted that “0” to “3” in FIGS. 9A and 9B are the duty when driving the mirror 54 a on which the light transmitted through the region with the numerical value is incident, and 5% and 5%, respectively. 0.4%, 6.25%, 25%
It corresponds to. The rotation direction of the color wheel 52 is counterclockwise in FIGS. In addition, the regions marked with “0” to “3” can be considered as the light transmission regions in which the transmitted light is directly incident on the integrator 53.

In the Super Spread LUT, each exposure of R, G, and B is performed 16 times per one rotation of the color wheel 52 as shown in FIGS. 56 is conveyed by one pixel. Therefore, for example, the filter 52B and the filter 5 of the color wheel 52 are
If the exposure of the photographic printing paper 56 is started immediately after the spoke 52b between the 2R and the 2R passes, the color wheel 52 is exposed.
In the first lap of, as shown in FIG.
By driving 4a with a duty of "0", the light transmitted through the area immediately after passing through the spokes 52b is reflected by the mirror 54a and reaches the photographic paper 56. Then, while the printing paper 56 is moved by a total of 4 pixels, the mirror 5
By always driving 4a with a duty of "0",
The transmitted light of the filter 52R is guided to the photographic printing paper 56 via the mirror 54a (end of the first to fourth exposures).

Next, while the photographic printing paper 56 is moved by two pixels, the mirror 54a is driven with the duty "1" so that the light transmitted through the filter 52R is guided to the photographic printing paper 56 through the mirror 54a. (End of 5th and 6th exposure). Then, while the photographic paper 56 is moved by 3 pixels,
By driving the mirror 54a with a duty of "2", the transmitted light of the filter 52R is guided to the printing paper 56 via the mirror 54a (7th to 9th exposure ends). After that, while the photographic paper 56 is moved by 7 pixels,
By driving the mirror 54a with the duty "3", the transmitted light of the filter 52R is guided to the photographic printing paper 56 via the mirror 54a (10th to 16th exposure ends).

Next, the light transmitted through the filter 52G and the filter 52B is sequentially exposed to the photographic paper 56. Even in these cases, the exposure is performed by the same method as the exposure through the filter 52R. Then, the exposure for the first round of the color wheel 52 is completed.

Here, one of the color wheels 52 described above is used.
Since the mirror 54a driven by the duty “0”, “1”, and “2” is used for each of the R, G, and B exposures on the fourth cycle, four, two, and three mirrors are used, respectively. After the second turn of the color wheel 52, the mirror 54a can no longer be driven by these duties. All that is possible is to use the remaining 48 mirrors 54a driven by duty "3". Therefore, in the second to fourth laps of the color wheel 52, as shown in FIG.
16 exposures are performed by the mirror 54a driven by the duty "3".

As described above, in the Super Spread LUT, the R exposure is 16 times per one turn of the color wheel 52.
The exposure is performed once, and the color wheel 52 rotates four times to 64.
This means that the exposure has been performed twice. Since such exposure is the same for the remaining G and B exposures, a total of 192 exposures are performed to form one dot of a color image.

[0020]

By the way, printing paper 56 is used.
Sensitivity varies depending on the manufacturer. For example, when the photographic paper 56 with low sensitivity is used, the photographic paper 56 with normal sensitivity is used.
However, if the exposure is performed with the exposure amount for, the density of the printed image cannot be sufficiently obtained. Therefore, in such a case, for example, a method may be considered in which the duty for driving the mirror 54a is made higher than usual and the exposure time of the printing paper 56 is made longer than usual.

However, with the conventional Super Spread LUT exposure algorithm, it is difficult to raise the duty more than this (25% or more). The reason is as follows.

When the spokes 52b are located in the light transmitting area of the color wheel 52, the light incident on the integrator 53 is not a monochromatic light but a mixed color of light that has passed through the filters located on both sides of the spoke 52b. Become. Since such light cannot be used for the exposure, in this case, the exposure by the mixed color light is avoided by turning off the mirror 54a, for example.

For example, in the above-mentioned exposure algorithm of the Super Spread LUT, as shown in FIGS.
Since the mirror 54a used for exposure using the light transmitted through the light transmission regions R ₁ , G _1, and B ₁ just before the light b enters is driven at the duty “3” (25%), During the remaining 75% when the mirror 54a is turned off, the spokes 52b form the light transmission region R ₁ · G of the color wheel 52.
_It exceeds ₁ · B ₁ .

However, since the color wheel 52 rotates at a high speed of 3200 rpm as described above, when the duty is further increased, the light transmitted through the light transmission regions R ₁ , G ₁ , B ₁ immediately before the spoke 52b is used. Photographic paper 5
During the exposure of 6, the spoke 52b is moved to the light transmission region R ₁
Comes into G ₁ and B ₁ . Therefore, it is theoretically impossible to increase the duty to 25% or more in order to avoid the exposure due to the above-described mixed color light.

The present invention has been made in order to solve the above problems, and an object thereof is to prevent the exposure due to mixed color light and to prevent the exposure amount to the photographic paper even when the photographic paper having low sensitivity is used. It is an object of the present invention to provide a photographic printing apparatus which employs an exposure algorithm capable of increasing the density of the printed image to sufficiently obtain the density of the printed image.

[0026]

In order to solve the above-mentioned problems, a photographic printing apparatus according to the invention of claim 1 has a light source for emitting light and a plurality of color filters arranged side by side. A color wheel that rotates so that each color filter can be sequentially transmitted, and a light modulation element that has a plurality of pixels and that modulates the light transmitted through the color wheel for each pixel according to image data and irradiates the photosensitive material. In the photoprinting apparatus having a control means for driving and controlling each pixel of the light modulation element, the control means irradiates a light-sensitive material with light transmitted through a region immediately before a joint between adjacent color filters in a color wheel. For the pixels of the light modulation element used for the color wheel rotation, the duty is different from the maximum value of the multiple duty set based on the number of gradations to be realized. Thus the joint is characterized in that the drive control at a duty following duty determined according to the maximum rotational speed of the color wheel that does not enter the above area.

According to the above arrangement, the light emitted from the light source passes through the predetermined color filter of the rotating color wheel and enters the light modulation element, and the light modulation element of the light modulation element is controlled based on the drive control of the control means. The photosensitive material is irradiated from each pixel.

Here, the pixels of the light modulation element, which are used to irradiate the light-sensitive material with the light transmitted through the area immediately before the joint, are driven and controlled by the control means by the duty that simultaneously satisfies the above conditions. The rotation of the color wheel causes the joint to enter the region, so that it is possible to surely avoid the inconvenience that the light passing through the color filters sandwiching the joint, that is, the mixed color light is applied to the photosensitive material. Moreover, since the duty for driving the pixel does not also serve as the maximum value of the plurality of duties set based on the number of gradations to be realized unlike the conventional case, while avoiding the inconvenience, It is possible to increase the maximum value above the conventional value.

That is, conventionally, when an attempt is made to increase the duty, the duty for driving the pixel is set to the maximum value of a plurality of duty values set based on the number of gradations to be realized (hereinafter, referred to as the first duty). And a duty determined according to the maximum rotation speed of the color wheel such that the joint does not enter the area due to the rotation of the color wheel (hereinafter referred to as the second duty). So the first
Increasing the duty of 2 inevitably increases the second duty, and as a result, the situation where the seam falls within the region when the color wheel rotates. Therefore, it was not possible to increase only the first duty. However, in the above configuration, the first duty and the second duty are set to be different from each other, so that it is possible to increase the first duty without changing the second duty.
When the first duty is increased, all of the plurality of duties set based on the number of gradations to be realized are shifted in the direction of increasing as a whole.

Therefore, according to the above arrangement, the exposure amount to the photosensitive material can be increased while avoiding the exposure by the mixed color light, whereby the printed image can be obtained even when the photosensitive material having low sensitivity is used. It is possible to obtain sufficient concentration.

In order to solve the above-mentioned problems, a photographic printing apparatus according to a second aspect of the present invention has the structure of the first aspect.
The control means is a drive signal for turning ON / OFF each pixel of the light modulation element according to exposure / non-exposure of the photosensitive material, and each pixel is turned ON after a predetermined time has elapsed since the drive signal was applied. It is characterized in that a drive signal that brings about a state is given to each pixel.

With the above arrangement, since the exposure start timing of the photosensitive material is delayed, the time until the joint of the color wheel reaches the region immediately before the joint can be gained by the rotation of the color wheel. This makes it possible to increase the rotation speed of the color wheel so that the joint does not reach the above region, and as a result, the processing speed can be improved even when a photosensitive material having low sensitivity is used. Further, when the rotation speed of the color wheel is not increased, it is possible to reliably avoid the exposure with the mixed color light.

In order to solve the above-mentioned problems, a photographic printing apparatus according to the invention of claim 3 has the following structure:
The control means controls ON time and OFF of each pixel on the time axis.
Each pixel is ON across a time position that is approximately 1/2 of the sum of time
It is characterized in that a drive signal that brings about a state is given to each pixel.

According to the above construction, the time taken for the joint of the color wheel to reach the area is certainly lengthened, and as a result, the effect of the construction of claim 3 can be obtained reliably.

In order to solve the above-mentioned problems, a photographic printing apparatus according to the invention of claim 4 has the following structure:
The control means is a maximum value of a plurality of duty set based on the number of gradations to be realized, the pixel of the light modulation element provided for irradiation of the light-sensitive material with the light transmitted through the area immediately after the joint. It is characterized in that the drive control is performed with a duty different from that.

According to the above arrangement, the ON time of the pixel of the light modulation element used for irradiating the photosensitive material with the light transmitted through the region immediately after the joint is shortened, and as a result, the region immediately before the joint is obtained. ON state of the pixel of the light modulation element that is used for irradiating the light-sensitive material with the light that has passed through and the ON state of the pixel of the light modulation element that is used for irradiating the light-sensitive material with the light that has passed through the region immediately after the joint. The time between states can be extended. As a result, it is possible to surely avoid the above-mentioned joint from reaching the region immediately before and immediately after that, and it is possible to surely avoid the exposure by the mixed color light.

[0037]

BEST MODE FOR CARRYING OUT THE INVENTION Regarding one embodiment of the present invention,
The following is a description with reference to FIGS.

As shown in FIG. 2, the photographic printing apparatus according to this embodiment includes a light source 1, a color wheel 2, an integrator 3, condenser lenses 4 and 5, a DMD 6, and
The printing lens 7 and the control unit 8 (control means) are provided.

The light source 1 is composed of, for example, a halogen lamp. The color wheel 2 is shown in FIGS.
As shown in (d), substantially fan-shaped R (red), G
(Green) and G (blue) filters 2R, 2G, and 2B are arranged in parallel, and the light from the light source 1 is filtered by each color filter 2R, 2G.
Rotate counterclockwise in the figure around the rotation shaft 2a so that 2B can be sequentially transmitted. Filter 2R and filter 2
The G, the filter 2G and the filter 2B, and the filter 2B and the filter 2R are connected by the spokes 2b ₁ , 2b ₂ and 2b ₃ , respectively.

The integrator 3 diffuses the light that has passed through the color wheel 2 and emits uniform light. The condenser lenses 4 and 5 sequentially collect the light from the integrator 3 and irradiate it on the DMD 6. The printing lens 7 is DM
Printing paper 9 which is a photosensitive material at a predetermined magnification with the reflected light from D6
It is a lens for forming an image.

The DMD 6 has the same structure as that of the conventional one, and is composed of, for example, 16 μm × 16 μm microscopic rockable micromirrors (hereinafter simply referred to as “mirrors”) that are planar in 1024 rows and 1280 columns. It is arranged in. Therefore, a total of about 1.31 million mirrors are arranged. Each mirror corresponds to one pixel, and a substrate (not shown) is provided via a post (not shown).
It is fixed to. The exposure of the photographic printing paper 9 is controlled by adjusting the tilt of each mirror according to the output image data of the control unit 8 which will be described later, and changing the reflection direction of the light from the light source 1 that has passed through the color wheel 2.

That is, when the photographic printing paper 9 is exposed, the light from the color wheel 2 is reflected in the photographic printing paper 9 direction.
A predetermined mirror is tilted according to the output image data of the control unit 8. On the other hand, when the photographic paper 9 is not exposed, a predetermined mirror is tilted according to the output image data of the control unit 8 so that the light from the color wheel 2 is reflected off the optical path to the photographic paper 9.

Therefore, the DMD having such an action
Reference numeral 6 constitutes an optical modulation means described in the claims, in which light transmitted through the color wheel 2 is modulated for each pixel in accordance with image data and guided to the photographic printing paper 9.

In this embodiment, the optical axis connecting the light source 1 and the DMD 6 is about 20 ° with the optical axis connecting the DMD 6 and the printing paper 9.
Although the above-mentioned constituent members (excluding the control unit 8) including the DMD 6 are arranged so as to form the angle of, the angle is not limited to the above.

In the present embodiment, the so-called scanning exposure method is adopted in which the photographic printing paper 9 is exposed while it is being conveyed based on the exposure algorithm of the Super Spread LUT, while it is being used for actual exposure. The vertical mirror is 19
There are only about 250,000 mirrors in two rows and 1280 columns.

The control unit 8 is provided with a look-up table (LUT) which multiplies 8-bit input image data corresponding to a predetermined density by the sensitivity characteristic γ of the printing paper 9 to generate 12-bit output image data. With this look-up table, a drive signal having a predetermined duty is applied to each mirror of the DMD 6, and the exposure time of the printing paper 9 is controlled for each mirror of the DMD 6. The details will be described later.

The duty (%) means the photographic paper 9
The ratio of the time during which the mirror is ON in the time required to carry one pixel of the above is shown. As the duty increases, the exposure time of the printing paper 9 becomes longer. . The duty is also expressed by the following formula. (Mirror ON time / (Mirror ON time + Mirror OFF time)) x 100

In a digital exposure device using a DMD, gradation is not obtained by changing the duty, but gradation is obtained by changing the number of ON / OFF mirrors. Therefore, for example, LCD (Liquid Crystal)
In a digital engine using a Display) or PLZT exposure head, when the look-up table is changed, the duty changes in many cases.
When using, the duty does not change when the look-up table is changed, but the number of mirrors used changes.

Next, the operation of the photographic printing apparatus having the above structure will be described.

First, the color wheel 2 is set to, for example, 3200.
While rotating at rpm, the photographic printing paper 9 is conveyed at such a speed that the four rotations of the color wheel 2 convey the DMD 6 by an amount corresponding to the line 192 of the mirror.

When the light source 1 is turned on, the light emitted from the light source 1 passes through, for example, the filter 2R of the color wheel 2, is diffused by the integrator 3, and then is condensed on the light reflecting surface of the DMD 6 by the condenser lenses 4 and 5. Collected. By controlling the tilt of each mirror in the DMD 6, the pixels of the photographic printing paper 9 to be exposed are irradiated with the light reflected by a predetermined mirror of the DMD 6 through the printing lens 7, and the pixels of the photographic printing paper 9 which should not be exposed. Is not irradiated with the reflected light from the DMD 6.

In the exposure algorithm of the Super Spread LUT, the color wheel 2 is rotated four times while the photographic printing paper 9 is conveyed by the amount corresponding to the 192 rows of the mirror. Then, while conveying the photographic printing paper 9, each of the R, G, and B exposures is performed 16 times per one rotation of the color wheel 2, and such exposure of each color 16 times is performed for four rotations of the color wheel 2. , One pixel of the printing paper 9 is formed. This will be described with reference to FIG.

FIG. 3 shows the exposure amount of the photographic printing paper 9 in the exposure area of the photographic printing paper 9 corresponding to the mirror area of the 192nd row of the DMD 6 in correspondence with the number of mirrors used (including the number of OFF mirrors). It is schematically drawn for each color. The length a in the figure corresponds to the number of mirrors (16 mirrors in this embodiment) used for exposing the same pixel of the printing paper 9. The length b indicates the amount of movement of the photographic printing paper 9 during exposure of a predetermined color (in this embodiment, the amount corresponding to 16 mirrors). As a result, in the present embodiment employing the scanning exposure method, the exposure amount of the photographic printing paper 9 is schematically represented as a parallelogram for each color as shown in FIG.

Therefore, for example, assuming that the exposure of the photographic printing paper 9 is started immediately after the spoke 2b ₃ between the filter 2B and the filter 2R of the color wheel 2 is passed, the light source in the first turn of the color wheel 2 is By transmitting the light from 1 through the filters 2R, 2G, and 2B in order,
The photographic printing paper 9 is sequentially exposed with the exposure amounts shown in the regions R1-1, G1-1, and B1-1. Similarly, in the second lap of the color wheel 2, the regions R1-2, G1-2, B1-
The photographic printing paper 9 is sequentially exposed with the exposure amount shown in FIG. 2, and in the third turn of the color wheel 2, the areas R1-3, G1-3,
The photographic printing paper 9 is sequentially exposed with the exposure amount shown in B1-3, and in the fourth round of the color wheel 2, the areas R1-4, G
The printing paper 9 is sequentially exposed with the exposure amounts 1-4 and B1-4.

In this way, for the predetermined pixels of the photographic printing paper 9, in the first rotation of the color wheel 2, the exposure by 16 mirrors is performed for each color, so 16 × 3 = 48 mirrors are used. To be done. Since such exposure is performed for four rounds of the color wheel 2, 48 × 4 = 19 as a whole.
Two mirrors are used, and as a result, one color dot is formed on the printing paper 9 by ON / OFF control of a total of 192 mirrors.

That is, when the exposure for four rotations of the color wheel 2 is completed, dots formed by 192 mirrors will appear on the photographic printing paper 9 conveyed by 192 pixels. After that, each time the photographic paper 9 is exposed once (every time the photographic paper 9 is conveyed by one pixel),
Dots formed by 192 mirrors will appear one after another.

When the color wheel 2 is rotated for a total of 5 to 8 turns, as shown in FIG.
In the first lap of those, regions R2-1, G2-1, B2
The photographic printing paper 9 is sequentially exposed with the exposure amount shown by −1, and the regions R2-2, G2-2,
The photographic printing paper 9 is sequentially exposed with the exposure amount shown in B2-2, and the areas R2-3 and G2 are provided at the third turn of the color wheel 2.
-3, B2-3 are used to sequentially expose the photographic printing paper 9, and in the fourth round of the color wheel 2, the area R2-
4, G2-4, B2-4 with the exposure amount shown
Are sequentially exposed. After that, the total of 9 of the color wheel 2
The same applies to rotations of 12 laps, 13 to 16 laps, ....

Next, the exposure algorithm of the present invention will be described below.

The control unit 8 controls the mirror of the DMD 6 used for irradiating the photographic printing paper 9 with the light transmitted through the region immediately before the joint between the adjacent color filters in the color wheel 2 to the number of gradations to be realized. A duty different from the maximum values of the plurality of duties set based on the above, and a duty equal to or less than the duty determined according to the maximum rotation speed of the color wheel 2 so that the joint does not enter the above area due to the rotation of the color wheel 2. The drive is controlled by. This will be specifically described with reference to FIGS. 1 (a) to 1 (d).

FIGS. 1 (a) to 1 (d) show the duty of the mirror that is driven when the light transmitted through a predetermined region of the color wheel 2 is guided to the photographic paper 9 for each light transmission region. It is a thing. It should be noted that “0” to “3” in FIGS. 3A to 3D are duty when driving the mirror on which the light transmitted through the area with the numerical value is incident, and the combination of the duty. By 1
There are four different types of duty that can realize an image of 4096 gradations with 2-bit output image data, and the higher the value, the greater the duty. Further, it is possible to consider that the areas marked with “0” to “3” are areas in which the transmitted light is directly incident on the integrator 3.

In the exposure of each color, in order to match the number of mirrors driven at each duty “0” to “3” with that of the conventional one, the duty becomes smaller in order.
There are 4, 2, 3 and 55 sheets.

Further, in the following exposure operation, the control section 8 turns on each mirror of the DMD 6 according to the exposure / non-exposure of the printing paper 9 so that the dots can be formed well.
A drive signal for turning on / off, and a drive signal for turning on / off the mirror with the time position approximately half of the sum of the ON time and the OFF time of the mirror on the time axis sandwiched therebetween. The respective mirrors are driven and controlled by the addition to the above. This point will be described later.

In this embodiment, the control section 8 carries out the following drive control for each mirror of the DMD 6. For example, in the R light exposure, the spokes 2b ₁ are formed on the first and second laps of the color wheel 2 as shown in FIGS.
Of a predetermined mirror that reflects the light transmitted through the region R ₁ immediately before passing through the photographic paper 9 in the direction of the photographic paper 9 with the duty “0”, and the region R immediately after the spoke 2b ₃ passes through.
A predetermined mirror that reflects the light transmitted through ₂ toward the printing paper 9 is driven with a duty of "0". Meanwhile, the remaining one
The mirrors that reflect the light that has respectively passed through the areas 4 to 9 toward the photographic printing paper 9 are driven with a duty “3”.

In the first and second laps of the color wheel 2, the four mirrors driven by the duty "0" are used up as described above.
After the lap, the mirror can no longer be driven with the duty “0”.

Therefore, on the third turn of the color wheel 2, as shown in FIG. 7C, a predetermined mirror for reflecting the light transmitted through the region R ₁ immediately before the spoke 2b ₁ passes toward the photographic paper 9 direction. Is driven with a duty “1”, and a predetermined mirror that reflects the light transmitted through the region R ₂ immediately after the spoke 2b ₃ has passed toward the printing paper 9 is driven with a duty “1”. On the other hand, the mirror that reflects the light, which has respectively passed through the remaining 14 areas, toward the photographic paper 9 is driven at the duty “3”. At this point, the two mirrors driven with the duty “1” have been used up.

Next, on the fourth turn of the color wheel 2, as shown in FIG. 3D, the light transmitted through the region R ₁ immediately before the spoke 2b ₁ passes is reflected toward the photographic paper 9 in a predetermined manner. While driving the mirror with duty “2”,
A predetermined mirror that reflects the light transmitted through the region R ₂ immediately after the spoke 2b ₃ has passed toward the photographic paper 9 is driven with a duty “2”. At this point, there is one mirror left to drive at duty “2”, so
The mirror that reflects the light transmitted through any one of the remaining 14 areas (for example, the area corresponding to the fifth exposure in FIG. 6D) toward the photographic paper 9 is set to the duty “2”. Drive with. Then, the mirror that reflects the light that has respectively passed through the remaining 13 areas toward the photographic printing paper 9 is driven with a duty of "3".

Such drive control is exactly the same for the exposure using the remaining G light and B light.

The drive control of the mirror according to the light transmitting region shown in FIGS. 1A to 1D is merely an example, and the control is not limited to this control. Further, regardless of where on the color wheel 2 the exposure of the photographic printing paper 9 starts, the mirror drive control is exactly the same as above.

As described above, each of the spokes 2b ₁ and 2b ₂
· 2b ₃ immediately before the region R ₁ · G ₁ · B ₁ and area R ₂ · G ₂ · B immediately following each spoke 2b ₁ · 2b ₂ · 2b ₃
By using the mirror driven at a duty smaller than the maximum duty "3" in any rotation of the color wheel 2, the exposure using the light transmitted through ₂ is performed, for example, after the duty "3". It is possible to set the extremely high duty “2” to the maximum value in the range where the spoke does not cover the light transmission area, that is, the maximum duty so far, 25%, and as a result,
It becomes possible to set the duty “3” to 25% or more inevitably.

Therefore, in the prior art, the duties “0”, “1” and “2” are 5%, 5.4% and 5.4%, respectively.
Although it was set to 6.25%, according to the present invention, it is set to 25%.
If it is less than or equal to%, theoretically, it is possible to set it to each of these values or more. Also for the duty “3”, the minimum operation time of the mirror is, for example, 10 μsec.
As a result, it is theoretically possible to set the value to 60 to 70%.

If the writing time to the memory for driving the DMD 6 mirror is not considered, theoretically,
Although the duty can be increased up to 100% or more, it is impossible to realize such a duty because it is necessary to take such a writing time into consideration.

Therefore, according to the present invention, it is possible to increase all the four types of duty as compared with the conventional one, and thus it is possible to increase the exposure time of the printing paper 9. Therefore, for example, even when the photographic printing paper 9 having low sensitivity is used, the exposure amount to the photographic printing paper 9 can be increased and the density of the printed image can be sufficiently obtained while avoiding the exposure by the mixed color light.

Further, since it is possible to appropriately expose the photographic printing paper 9 having low sensitivity without raising the voltage of the light source 1 or inserting a filter in the optical path, it is possible to increase the size of the apparatus or the structure. There is no complication. Furthermore, since it is not necessary to reduce the rotation speed of the color wheel 2 in order to increase the duty, it goes without saying that the processing speed does not decrease.

Further, as described above, the control section 8 puts a drive signal on the time axis so that the mirror is turned on with a time position of about 1/2 of the sum of the ON time and the OFF time of the mirror being sandwiched. Is given to each mirror. For example, when the mirror is driven at a duty of 10%, if the sum of the ON time and the OFF time of the mirror is 100%, the mirror is in the ON state at 45% to 55% with the 50% position sandwiched. A signal having such a driving waveform is given to each mirror. In this case, since the exposure start timing of the photographic printing paper 9 is delayed, the time during which each spoke does not reach the regions R ₁ , G _1, and B ₁ can be surely lengthened. This allows the color wheel 2
It is possible to increase the rotation speed of the above, and even when the photographic printing paper 9 having low sensitivity is used, it is possible to further improve the processing speed while obtaining the effects of the present invention described above.
Further, if the photographic printing paper 9 having the normal sensitivity is used, the processing speed can be remarkably improved as compared with the conventional case.

The drive signal may be any signal that can delay at least the exposure start timing of the printing paper 9. That is, it is sufficient if the drive signal is such that the mirror is turned on after a predetermined time has passed since the drive signal was applied to the mirror.

In the present embodiment, the control section 8 controls the DMD 6 so that the exposure time of the light transmitted through the area immediately before and after each spoke to the photographic paper 9 is always equal to or less than the duty "2". I control the mirror,
The effect of the present invention described above can be sufficiently obtained if the mirror drive control is performed in the exposure using the light that transmits at least the region immediately before the spoke.
The configuration in which the above-mentioned mirror drive control is performed even when the exposure is performed using the light transmitted through the region immediately after the spoke, in particular, uses a drive signal that delays the exposure start timing of the photographic printing paper 9 as in the present invention. Very effective in cases.

When the above-mentioned mirror drive control is performed only in the exposure using the light transmitted through the region immediately before the spoke, the above-mentioned mirror drive is also performed in the exposure using the light transmitted through the region immediately after the spoke. It goes without saying that the variation of the mirror drive control is wider than that in the case of performing the control (for example, the exposure using the light transmitted through the region immediately after the spoke is performed by the mirror driven by the duty “3”, the duty “ 0 ”,“ 1 ”,
A mirror driven by "2" can be used for exposure using light transmitted through other regions).

The diameter of the integrator 3 can be reduced without changing the size of the color wheel 2, or conversely, the size of the integrator 3 can be kept unchanged.
It is also possible to increase the time during which the spokes do not reach the areas R ₁ , G _1, and B ₁ of the color wheel 2 by increasing the diameter of the area. Therefore, by appropriately setting the size of the color wheel 2 and / or the integrator 3 together with the mirror drive control of the present invention, it becomes possible to drive the mirror with a higher duty, and a higher exposure amount can be obtained. Obtainable.

In the present embodiment, the DMD 6 is taken as an example of the light modulation element, but any device capable of performing scanning exposure may be used.

[0080]

The photographic printing apparatus according to the invention of claim 1
As described above, the control unit controls the gradation of the pixel of the light modulation element that is used to irradiate the photosensitive material with the light transmitted through the region immediately before the joint between the adjacent color filters in the color wheel. A duty that is different from the maximum value of the multiple duty set based on the number, and that is less than or equal to the duty determined according to the maximum rotation speed of the color wheel so that the joint does not enter the above area due to the rotation of the color wheel. The drive is controlled by.

Therefore, it is possible to increase the exposure amount to the light-sensitive material while avoiding the exposure by the mixed-color light, and thereby, for example, even when the light-sensitive material having low sensitivity is used, the density of the printed image is sufficiently increased. There is an effect that can be put out.

As described above, in the photographic printing apparatus according to the second aspect of the present invention, in the configuration of the first aspect, the control means turns on each pixel of the light modulation element according to exposure / non-exposure of the photosensitive material. A drive signal for turning on / off the drive signal is provided to each pixel such that each pixel is turned on after a predetermined time has elapsed since the drive signal was applied.

Therefore, since the exposure start time of the photosensitive material is delayed, it is possible to increase the rotational speed of the color wheel so that the joint of the color wheel does not cover the area immediately before the joint, and as a result, the color wheel of claim 1 In addition to the effect of the constitution, there is an effect that the processing speed can be improved even when a photosensitive material having low sensitivity is used. Further, when the rotational speed of the color wheel is not increased, it is possible to reliably avoid the exposure due to the mixed color light.

As described above, in the photographic printing apparatus according to the third aspect of the present invention, in the configuration of the second aspect, the control means has a sum of the ON time and the OFF time of each pixel on the time axis, which is approximately 1 The drive signal is applied to each pixel such that each pixel is turned on across the time position of / 2.

Therefore, it takes a long time for the joint of the color wheel to reach the area, and as a result, the effect of the structure of claim 3 can be obtained.

As described above, in the photographic printing apparatus according to the invention of claim 4, in the structure of claim 3, the control means is provided for irradiating the light-sensitive material with the light transmitted through the region immediately after the joint. In this configuration, the pixels of the light modulation element are driven and controlled with a duty different from the maximum value of the plurality of duty set based on the number of gradations to be realized.

Therefore, in addition to the effect of the structure of claim 3, the ON time of the pixel of the light modulation element used for irradiating the photosensitive material with the light transmitted through the region immediately after the joint is shortened. Thus, it is possible to surely avoid the joint immediately before and immediately after the area, and to surely avoid the exposure by the mixed color light.

[Brief description of drawings]

1 (a) to 1 (d) are views showing, in a photographic printing apparatus according to an embodiment of the present invention, for guiding light passing through a predetermined region of a color wheel to photographic paper for each circumference of the color wheel. It is explanatory drawing which shows the duty of the mirror driven at that time for every light transmission region.

FIG. 2 is an explanatory diagram showing a schematic configuration of the photographic printing apparatus.

FIG. 3 shows the exposure amount of the photographic paper in the exposure area of the photographic paper corresponding to the mirror area of 192 rows of the DMD of the above-mentioned photoprinting apparatus in correspondence with the number of mirrors used (including the number of OFF mirrors). It is an explanatory view drawn typically for each color.

FIG. 4 is a cross-sectional view showing a schematic configuration of a conventional photographic printing apparatus.

5 (a) and 5 (b) are duty cycles of a mirror that is driven when the light passing through a predetermined area of the color wheel is guided to the photographic paper for each circumference of the color wheel in the above-mentioned photographic printing apparatus. FIG. 6 is an explanatory diagram showing each of the light transmission regions.

FIG. 6 is an explanatory diagram showing a schematic configuration of a DMD included in the photo printing apparatus.

FIG. 7A is an explanatory diagram showing a color area of a mirror corresponding to a predetermined pixel of a printing paper exposed based on an exposure algorithm of Spread LUT. (B) is Super Spread L
FIG. 6 is an explanatory diagram showing a color area of a mirror corresponding to a predetermined pixel of photographic paper that is exposed based on an exposure algorithm of UT.

[Explanation of symbols]

1 Light source 2 Color wheel 2R filter (color filter) 2G filter (color filter) 2B filter (color filter) 2b ₁ spoke (joint) 2b ₂ spoke (joint) 2b ₃ spoke (joint) 6 DMD (light modulator) 8 control Part (control means) 9 photographic paper (photosensitive material)

Continuation of the front page (56) Reference JP-A-8-227113 (JP, A) JP-A-9-160141 (JP, A) JP-A-4-96046 (JP, A) JP-A-2-73341 (JP , A) (58) Fields investigated (Int.Cl. ⁷ , DB name) G03B 27/00-27/80 G02B 5/20

Claims (4)

(57) [Claims] 1. A light source that emits light and a plurality of color filters are arranged side by side, a color wheel that rotates so that light from the light source can sequentially pass through each color filter, and a plurality of pixels. A photoprinting apparatus comprising: a light modulator for modulating the transmitted light for each pixel in accordance with image data and irradiating the photosensitive material with light; and a controller for driving and controlling each pixel of the light modulator. Is a plurality of pixels that are set based on the number of gradations to be realized for the pixels of the light modulation element that are used to irradiate the photosensitive material with the light that has passed through the region immediately before the joint between the adjacent color filters in the color wheel. Is different from the maximum value of the duty of the color wheel, and it corresponds to the maximum rotation speed of the color wheel so that the joint does not enter the above area due to the rotation of the color wheel. A photoprinting device characterized by being driven and controlled at a duty equal to or less than the duty determined by the above. 2. The control means is a drive signal for turning ON / OFF each pixel of the light modulation element according to exposure / non-exposure of the photosensitive material, and a predetermined time has elapsed after the drive signal is applied. The photographic printing apparatus according to claim 1, wherein a drive signal for turning on each pixel later is given to each pixel. 3. The control means turns ON each pixel on the time axis.
3. The photographic printing apparatus according to claim 2, wherein a drive signal is provided to each pixel so that each pixel is in an ON state with a time position of about 1/2 of the sum of time and OFF time interposed therebetween. 4. The control means sets a plurality of pixels of a light modulation element, which are used for irradiating a light-sensitive material with light transmitted through a region immediately after the joint, based on the number of gradations to be realized. 4. The photographic printing apparatus according to claim 3, wherein the drive control is performed with a duty different from the maximum value of the duty of.