JP2792874B2 - LCD color printer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention exposes three colors of red, green, and blue through a liquid crystal shutter that opens and closes in response to an electric signal to form a color image on a photoconductor. The present invention relates to a liquid crystal color printer for printing.

<Prior Art> Conventionally, as this type of liquid crystal color printer, for example, the one shown in FIG. 6 is known. This liquid crystal color printer has three color filters 33r, 33 for red, green, and blue.
g, 33b, receives a color switching signal output from the image output device 37 via the liquid crystal drive circuit 38, and performs step rotation by 3, and sequentially outputs R, G, and R out of the white light from the white light source 31. A rotating color filter 33 that transmits only B light for a predetermined time, and photosensitive paper
A large number of shutter elements 34a, 34b, 34c,... Are arranged on the upper surface of the paper 35 in the horizontal direction (line direction) of the paper, and R, G, and R are synchronized with the color switching signal from the liquid crystal drive circuit 38.
A liquid crystal shutter array is provided which receives the B image signal and opens the dot position of the color for the required exposure time.
Then, in a stationary state in which the feed rollers 36, 36 for feeding the photosensitive paper 35 in the vertical direction as shown by the arrow in the drawing are stopped, the rotary color filter 33 is rotated once by step rotation, and in synchronization with this, the liquid crystal shutter is rotated. The array 34 is sequentially opened by the R, G, B image signals, and one line of three-color exposure is performed on the photosensitive paper 35 through the same optical path, and then the liquid crystal shutter array 34 is fully closed. The photosensitive paper is transported in the vertical direction by one line by the feed rollers 36, 36, and three-color exposure of the next one line is similarly repeated.

<Problems to be Solved by the Invention> However, the conventional liquid crystal color printer described above is
In this method, one line of three-color exposure is performed in a stationary state where the feed of 35 is stopped, and one line of photosensitive paper is sent in a light-shielded state, and then the three-color exposure is performed again. Exposure is interrupted each time, and it takes a long time to print all lines, that is, one sheet. In addition, a high positioning accuracy corresponding to a narrow line width is required for the feeding and stopping of the photosensitive paper 35, and since the feeding and stopping are frequently repeated, the structure of the feed rollers 36 and 36 and the control mechanism thereof become complicated. However, there is a disadvantage that it becomes expensive.

Therefore, an object of the present invention is to print a color image quickly with a simple and inexpensive configuration by repeating three-color exposure for one line without interruption while feeding the photoconductor continuously and at a constant speed. It is to provide a liquid crystal color printer.

<Means for Solving the Problems> In order to achieve the above object, a liquid crystal color printer according to the present invention includes a spherical lens for linearly condensing white light from a white light source, and an optical axis in front of the spherical lens. The lens is arranged on a vertical surface at an interval in parallel with the lens, receives electric signals and is sequentially opened for a predetermined time to direct only red, green, and blue light of the white light to the focal point of the spherical lens. A three-color separation liquid crystal shutter made up of three linear liquid crystal shutters of R, G, and B that allow light to pass through a plurality of pixels in one line at the same time while transmitting light through different paths, and A number of shutter elements corresponding to the pixels are provided along the linear focal point of the spherical lens,
A liquid crystal shutter array that receives an image signal synchronized with the opening time of each of the R, G, and B shutters of the three-color separation liquid crystal shutter and opens each pixel for an exposure time required by each shutter element for each color; There is provided a feeding means for feeding the photoreceptor disposed on the front surface of the liquid crystal shutter array continuously and at a constant speed in a direction orthogonal to the lines in synchronization with the transmission time of one line of the three color image signals.

<Operation> White light emitted from a white light source so as to spread is collected by a spherical lens and linearly converges to a front focal point. 3 arranged on a plane perpendicular to the optical axis between the spherical lens and the focal point
The three line-shaped liquid crystal shutters of the color separation liquid crystal shutter receive electric signals and are opened, for example, in the order of R, G, and B for a predetermined time, and sequentially transmit only red, green, and blue light to the focus through different paths. To be transmitted. A liquid crystal shutter array provided with a number of shutter elements corresponding to pixels of one line along the linear focus receives image signals of R, G, and B synchronized with the transmission time of each color light, Each pixel is opened for each pixel for the exposure time required by each shutter element, and red, green, and blue light in the form of a line dot is sequentially passed toward the photoconductor. At this time, the photoconductor is fed by the feeding means continuously and at a constant speed in the direction orthogonal to the line in synchronization with the sending time of one line of the R, G, B image signals for one line. Since the incident paths of G, B light are different as described above, for example, a linear focus is first exposed on the photosensitive member slightly forward with respect to the feed direction with red light in the form of line dots, and then the exposure time During the linear focus is exposed to green light in the line dot-shaped already-traveled light portion of the photoconductor that has been sent immediately below the linear focus,
Further, the exposed portion is similarly exposed to blue light on the side opposite to the linear focus, thereby completing one line of three-color exposure. The line exposure is repeated without interruption, and the printing of one color image is completed. As described above, since the photoconductor is continuously fed at a constant speed and the line exposure is not interrupted, the printing time can be reduced, and the photoconductor feeding mechanism and the like can be simplified and reduced in cost.

<Example> Hereinafter, the present invention will be described in detail with reference to an illustrated example.

1 and 2 are a perspective view and a front view, respectively, showing an example of a liquid crystal color printer of the present invention, wherein 1 is a white light source which emits white light radially, and 2 is horizontally arranged on the front of the white light source 1. Is a kind of spherical lens that focuses the white light on the front focus F
A cylindrical lens whose light exit surface has a curved surface in both the vertical and horizontal directions so that light is condensed along the longitudinal direction and also converges light in the longitudinal direction. The cylindrical lens 3 is located on a horizontal plane that crosses the optical path between the cylindrical lens 2 and its focal point F. R, G, B are extended in parallel with the cylindrical lens 2 at an interval from each other.
The color switching signals input from the image output device 7 via the liquid crystal driving circuit 8 are sequentially opened for a predetermined period of time, and only the red, green, and blue lights of the white light are transmitted. A three-color separation liquid crystal shutter including three linear liquid crystal shutters 3r, 3g, and 3b of R, G, and B that simultaneously opens and closes light of a plurality of pixels in one line.

Reference numeral 4 denotes an array of shutter elements 4a, 4b, 4c,... Corresponding to the pixels of one line along the linear focal point F. The liquid crystal shutter array, which receives the R, G, B image signals input in synchronization with the color switching signal and opens for each pixel only for the exposure time required by each shutter element for each color, is a liquid crystal shutter array 4. The photosensitive paper 6 horizontally arranged on the front surface of the photosensitive paper 5 is continuous with the photosensitive paper 5 in a direction orthogonal to the line as shown by an arrow A in synchronization with the transmission time of one line of the R, G, B image signal. And a feed roller for feeding at a constant speed.

As shown in FIG. 4, the three-color separation liquid crystal shutter 3 faces the central opening of the light-shielding mounting plate 11 and fixes the light-shielding plate 12 having three rectangular windows 12r, 12g, and 12b. R, G, and B liquid crystal shutters 3r, 3g, and 3b each having the structure shown in FIG. 3 are fitted in the rectangular window, and are fitted on a common polarizing plate 19 on the incident side, which will be described later, in accordance with the rectangular window. The color filters 13r, 13g, and 13b, which transmit only red, green, and blue light, respectively, are attached. As shown in FIG. 3, the liquid crystal shutters 3r, 3g, and 3b are provided with transparent electrodes 15, 15 'on opposing surfaces of upper and lower transparent substrates 14, 14'. Films 16 and 16 'that align liquid crystal molecules in only one direction
Are formed so that their orientation directions are orthogonal to each other, and a so-called twisted nematic type in which a liquid crystal 18 of a nematic phase is filled with a sealing material 17 surrounding the four circumferences of the upper and lower transparent electrodes 15, 15 '. is there. Then, polarizing plates 19, 19 'whose polarization planes are orthogonal to each other are arranged outside the upper and lower transparent substrates 14, 14', and when a voltage is applied between the transparent electrodes 15, 15 ', the twisted nematic of the liquid crystal 18 is formed. While the light is blocked by the orthogonal polarizers 19 and 19 'due to the disappearance of the 90 ° optical rotation due to the twisted nematic, the light is transmitted by the 90 ° optical rotation due to the twisted nematic when no voltage is applied.

On the other hand, as shown in FIG. 5, the liquid crystal shutter array 4 has a light shielding plate 22 facing the central opening of the light shielding mounting plate 21.
The shutter elements 4a, 4b, 4 corresponding to one dot of an image, that is, a pixel, are provided in the central window 22a which is a light shielding plate.
c, ... are fitted in a straight line. Each shutter element has the same structure as that described in FIG. 3, and is opened for a required exposure time based on R, G, and B image signals corresponding to the respective element positions.

The operation of the liquid crystal color printer having the above configuration will be described below.

White light emitted radially from the white light source 1 is collected by the cylindrical lens 2 and linearly converges at the front focal point F. The three-color separation liquid crystal shutter 3 provided on a horizontal plane that crosses the optical path between the cylindrical lens 2 and the focal point F,
Receiving the color switching signal from the liquid crystal drive circuit 8, the linear liquid crystal shutters 3r, 3g, 3b are opened in this order for a predetermined time, and the white light is transmitted through the R, G, B color filters and time-division red. ,
The light becomes green light and blue light and arrives at the linear focal point F along different paths sequentially from the upper right, the upper right, and the upper left. The liquid crystal shutter array 4 in which the number of shutter elements 4a, 4b, 4c,... Corresponding to the pixels of one line are provided along the linear focus F corresponds to the time-division transmission time of each color light. Receiving the R, G, B image signals from the liquid crystal drive circuit 8 which is synchronized, each pixel is opened for each pixel for the exposure time required by each shutter element, and red, green, and blue light in the form of line dots is generated. The paper is sequentially passed toward the photosensitive paper 5.

At this time, the photosensitive paper 5 is moved by the feed rollers 6 and 6 in the direction orthogonal to the line A in synchronism with the transmission time of the color switching signal for three times, that is, one line of the image signal of R, G and B colors. In the direction (see FIG. 2), the light is sent continuously and at a constant speed, and the incident paths of the R, G, and B light to the liquid crystal shutter array 4 are different as described above. First, a line dot is exposed with red light on Pr on the front side of the center of
Next, during this red exposure time, green light is exposed in the form of line dots on top of the previously exposed Pr sent to Pg immediately below the liquid crystal shutter array 4, and Pb on the side from the center is exposed.
Are similarly exposed with blue light, and the three-color exposure for one line is completed. In this case, unlike the conventional example described with reference to FIG. 6, since the photosensitive paper 5 moves during exposure, the print pattern slightly blurs in the feed direction and spreads.
Since the size of the condensed dots of the liquid crystal shutter array 4 can be adjusted to be small enough to be small, and the exposure time for one color is 1 / of the feed time for one line, the exposure accuracy is hardly affected. Thus, the printing of one color image is completed by repeating the three-color exposure for one line without interruption.

As described above, according to the present invention including the above-described embodiment, the feeding of the photosensitive paper 5 is continuous and at a constant speed, and the line exposure is not interrupted. The structure can be greatly reduced, and the structure of the feed rollers 6, 6 for feeding the photosensitive paper 5 can be simplified and reduced in cost.

It goes without saying that the present invention is not limited to the illustrated embodiment.

<Effects of the Invention> As is apparent from the above description, the liquid crystal color printer of the present invention condenses white light from a white light source linearly at its focal point with a cylindrical lens, while arranging the white light between the cylindrical lens and its focal point. The R, G, and B line-shaped liquid crystal shutters that are simultaneously opened and closed with respect to the light of a plurality of pixels in one line of the three-color separation liquid crystal shutter that is set are sequentially opened for a predetermined time, and the red, green, and blue shutters are opened.
The shutter elements of the liquid crystal shutter array in which green and blue lights are sequentially transmitted and the number of shutter elements corresponding to the pixels of one line are extended to the linear focal point, and each of the shutter elements of the R, G, B A three-color linear exposure is performed on a photoconductor that is continuously opened at a constant speed in a direction orthogonal to the line by opening each pixel for an exposure time required by each shutter element for each color by an image signal synchronized with a shutter opening time. Is repeated without interruption, so that the printing time can be greatly reduced while maintaining the same exposure accuracy as the conventional example, and a high-precision step feed mechanism per line width is not required. Can be simplified and reduced in cost.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an embodiment of a liquid crystal color printer of the present invention, FIG. 2 is a front view of the above embodiment, FIG. 3 is a sectional view showing a general structure of a liquid crystal shutter, and FIG. FIG. 5 is a perspective view of a liquid crystal shutter array of the above embodiment, and FIG. 6 is a perspective view showing a conventional liquid crystal color printer. 1 ... white light source, 2 ... cylindrical lens, 3 ...
3 color separation liquid crystal shutter, 3r, 3g, 3b ... liquid crystal shutter, 4
... A liquid crystal shutter array, 4a, 4b, 4c,... Shutter elements, 5... Photosensitive paper, 6.

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Kazuhiko Yanagihara 798, Miyadai, Kaisei-cho, Ashigara-gun, Kanagawa Prefecture Fuji Photo Film Co., Ltd. (56) References JP-A-61-215071 (JP, A) Field (Int.Cl. ⁶ , DB name) B41J 2/445

Claims (1)

(57) [Claims] 1. A spherical lens for linearly condensing white light from a white light source, and an electric signal arranged in parallel with the lens on a plane perpendicular to the optical axis in front of the spherical lens. Then, only the red, green, and blue light components of the white light component are transmitted through different paths toward the focal point of the spherical lens, respectively, and the light component is converted to light for a plurality of pixels in one line. On the other hand, a three-color separation liquid crystal shutter composed of three linear liquid crystal shutters of R, G, and B that open and close simultaneously, and a number of shutter elements corresponding to the pixels of one line are arranged along the linear focal point of the spherical lens. A liquid crystal that receives an image signal synchronized with the opening time of each of the R, G, and B shutters of the three-color separation liquid crystal shutter and opens each pixel for an exposure time required by each shutter element for each color. Shutter And Lee, a photosensitive member disposed on the front surface of the liquid crystal shutter array,
A liquid crystal color printer comprising a sending means for sending the three color image signals continuously and at a constant speed in a direction orthogonal to the lines in synchronization with the sending time of one line of the image signals of the three colors.