JP2003048338A - Print head and printing device for optical printer - Google Patents

Abstract

(57) Abstract: An object of the present invention is to improve printing efficiency by a light emitting element incorporated in a print head of an optical printer. A print head (76) is provided with the carriage (70).
, A head substrate 77 on which LEDs of each color are arranged, a panel shade 71, and an aperture 40. Each of the LED units 77R, 77B, and 77G includes a light-emitting diode 78 and a reflection mirror 80 that condenses light emitted from the light-emitting diode 78 to the exposure hole 40e of the aperture 40. The light-emitting diode 78 is a light-emitting element having a narrow directivity. Light emitted from the light-emitting diode 78 is applied to the reflection mirror 80, diffracted by the reflection surface 84, and reaches the center of the exposure hole 40e.
Most of the light emitted from the light emitting unit 78a is reflected by the reflection mirror 80.
Then, the light is reflected on the exposure hole 40e and condensed by the exposure hole 40e, so that the amount of light irradiated on the print medium 90 can be increased, and the printing efficiency can be increased.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a print head and a printing apparatus for an optical printer, and more particularly to a print head and a printing apparatus for an optical printer configured to expose a print medium having a photoconductor to light of a specific wavelength to develop a color. Regarding the device.

[0002]

2. Description of the Related Art Conventionally, as one of methods for producing a color photograph or a color print, a method of exposing a photosensitive paper to form an image such as a picture or a character is known. Also,
As a photosensitive paper, a photosensitive paper called a color medium (hereinafter, simply referred to as “printing medium”) has been developed (for example, see Japanese Patent Laid-Open No. 10-76706). The printing medium uses three types of cyan, magenta, and yellow microcapsules (hereinafter referred to as "Siris") containing different color-developing substances and photoinitiators as photosensitive materials. This printing medium is coated with a layer of photosensitive material that has a myriad of very small squirrels on the surface of a thin polyester support, which are then exposed to light to cure the siris to a specific color. After activating only Siris, it is crushed by applying pressure and developed, so that only an image of a predetermined color can be formed.

Next, the operation in the case of performing color printing on the above-mentioned print medium by a color printer (hereinafter, simply referred to as "printing device"), that is, the principle of coloring will be briefly described.

First, the print medium is irradiated with exposure light having a wavelength suitable for an image to be formed by using a print head for exposure. R (red) color, G for print head
Light emitting elements including light emitting diodes of (green) color and B (blue) color (hereinafter referred to as “LED”) are provided, and as shown in FIG. 10, the spectral characteristics depending on the characteristics of the respective light emitting elements are provided. R color is 630 nm, G color is 53
The amount of light has a peak at a wavelength of 0 nm and B color at 470 nm.

The exposure light cures the squirrel containing therein a coloring substance (rucodai) having a complementary color relationship with the wavelength of the exposing light, and inactivates the coloring substance contained in the squirrel. For example, assume that the exposure light is red light.

In this case, since the complementary color of the red light is the cyan light, the thyris containing the cyan coloring material (hereinafter,
(Called "Cyan squirrel") is inactivated.

The area exposed by the print head composed of the exposure head is in the paper feed direction by the paper feed roller, that is,
It is sent in the sub-scanning direction, and the next area is sent to the exposure head with paper. The paper feed roller is rotationally driven in the forward direction by the paper feed mechanism.

On the other hand, in the exposed area, the siris is crushed by the pressure roller which is moved along with the print head along the moving direction of the carriage, that is, the main scanning direction. Magenta and yellow squirrels that are active states other than passivated by exposure light, for example, red light, are crushed by a pressure roller, and the color-developing substance is chemically combined with an image-receiving layer formed on transparent polyester. Cause a reaction,
It develops red, which is the desired color.

Further, in order to accelerate the color development, the printing medium is heated by a heater using a heating element so that the printing medium can be output from the printing device in a state where the color development is almost completed. From the above-mentioned coloring principle, when the exposure light is red light and green light,
It can be easily understood that the color develops to yellow.

As mentioned above, printing media (printing paper)
Is sent out in the paper feeding direction by the paper feeding roller that is rotationally driven by the motor by the paper feeding mechanism.
The paper feeding operation by the paper feeding mechanism needs to be interlocked with an operation (hereinafter, referred to as "print head operation") in which a carriage having a print head for exposure moves along a carriage movement direction.

The carriage is movable within a range on both sides. Then, when the carriage reaches at least one of both sides or immediately before, the paper feed mechanism starts its operation to rotate the paper feed roller by a predetermined angle in the forward direction to move the paper. Move a fixed amount in the paper feed direction.

FIG. 11 is an enlarged vertical sectional view showing a conventional print head for an optical printer. As shown in FIG. 11, in the print head 1, the LEDs 2 of each color are mounted on the head substrate 3. The LED 2 is a chip type in which a rectangular light emitting portion 2a is molded by a case 2b. The print head 1 is provided with a panel shade 5 having an opening 4 for accommodating the LEDs 2, and an aperture 6 attached so as to overlap the lower surface of the panel shade 5.

An exposure hole (also referred to as a "pinhole") 7 is opened in the aperture 6 at a position facing each LED 2. Therefore, the aperture 6 has
The lights of three colors are prevented from overlapping each other by narrowing the light so that only the light from the light passes through the exposure hole 7 and is applied to the printing medium 8.

For this reason, the print head 1 is provided with the panel shade 5 and the aperture 6 so that the light of each color is not simultaneously irradiated, and the coloring accuracy of the print medium 8 is secured.

[0015]

However, conventionally, the light from the LEDs 2 of each of the three colors is narrowed down by the aperture 6 to prevent the interference of the lights of the respective colors due to the exposure. Light emitting part 2
Although the light 9a emitted from a toward the exposure hole 7 is applied to the print medium, the light 9b emitted to the side of the LED 2 does not pass through the exposure hole 7 and the amount of light applied to the print medium 8 is reduced. descend. Therefore, conventionally, there is a problem that it is difficult to improve the printing efficiency because a part of the amount of light emitted from the LED 2 is not applied to the printing medium 8.

Further, in the print head for an optical printer, a plurality of LEDs 2 are arranged to secure the light amount of each three colors. To shorten the printing time, the number of LEDs 2 is increased to increase the light amount to the printing medium 8. It is necessary to increase the number, and there is a problem that the cost increases.

Further, since the chip type LED 2 has not been mass-produced yet, it is difficult to obtain and the manufacturing cost is high.

Therefore, it is an object of the present invention to provide a print head and a printing apparatus for an optical printer which solve the above problems.

[0019]

In order to solve the above problems, the present invention has the following features. The invention according to claim 1 is an aperture having an exposure hole formed at a position facing a printing medium, and a light emitting element having a narrow directivity,
It is equipped with a reflection mirror that reflects the light from the light-emitting element so that it is focused on the exposure hole, and the light from the light-emitting element can be efficiently focused on the exposure hole. It is possible to increase the amount of light emitted and improve the printing efficiency.

According to a second aspect of the present invention, there is provided a printing apparatus configured to use the print head for an optical printer according to the first aspect to expose a print medium having a photoconductor to light of a specific wavelength to develop a color. The same action and effect as those of claim 1 are obtained.

[0021]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is an exploded perspective view showing an embodiment of a printing apparatus using a print head for an optical printer according to the present invention.

As shown in FIG. 1, the printing device 50 includes
An upper case 51 that fits together to form an accommodation space inside
A lower case 55, a drive mechanism 60 housed on the bottom plate of the lower case 55, and a control board 53 for controlling the drive mechanism 60.
And a removable media case 52 accommodating a plurality of sheet-shaped print media.

FIG. 2 is an exploded perspective view showing the structure of the drive mechanism of the printing apparatus shown in FIG. FIG. 3 is an overall configuration diagram of the drive mechanism of FIG. As shown in FIGS. 2 and 3, a boat-shaped frame (chassis) 61 is provided with a carriage 70 for moving and operating a print head 76 for exposing the taken-out print medium, and for developing and heating the medium. A drive motor 62 for driving each part, a pickup roller 63 for taking out one print medium to be exposed from the media case 52 shown in FIG. 1, a feed roller 65c and the like are mounted.

The carriage 70 has a print head 76 mounted therein, and also contains a pressure roller 75 (which is hidden and not visible in FIG. 3) for crushing the photosensitive material of the print medium. A fixing metal fitting (not shown) is provided at the tip of the carriage 70, and the encoder board 74 is attached to the upper surface shown in the drawing by the metal fitting. Further, the carriage 70 accommodates a guide protrusion 78 having a protrusion that fits into the spiral groove 72 a provided on the head drive shaft 72. The guide protrusion 78 is rotatably supported by a fitting 79.

The head drive shaft 72 is provided with a spiral groove 72a. When the drive shaft 72 rotates, a guide protrusion (not shown) of the carriage 70 fitted in the spiral groove 72a is formed in the spiral groove 72a. Move along. This allows
The carriage 70 is guided by the guide rollers 66 and 73 and reciprocates in the axial direction.

It should be noted that both ends of the shafts of the respective parts project from the chassis 61, and gears are respectively provided to drive the respective shafts. It constitutes a drive transmission mechanism for obtaining a desired rotation.

FIG. 4 is an exploded perspective view mainly showing the heating mechanism. Referring to FIG. 4 together with FIG. 2 and FIG. 3, the heating mechanism promotes color formation after crushing the unexposed color former of the print medium between the pressing shaft 100 and the pressure roller 75 after exposure. A heater 92 for heating is provided for this purpose. The heater 92 is made of an L-shaped metal piece provided with a heating element (not shown), and is attached near the medium discharge side by a heater fixing portion 91, attachment members 93, 94, 95 and the like.

FIG. 5 is a perspective view of the carriage 70 as viewed from the lower surface side. As shown in FIG. 5, the print head 76
Is the carriage 70 and the LED unit 77 for R color.
The head substrate 77 is provided with the R and B color LED units 77B and the G color LED units 77G, a panel shade 71, and an aperture 40.

The carriage 70 is provided with a pair of positioning pins 70c projecting (projecting upward in FIG. 5) on both sides toward the one end (rearward in FIG. 5). Further, a pair of carriage pins 70d for locking the aperture 40 is provided on each side of the carriage 70.

On the end surface 40a of the aperture 40, an R color LED unit 77R, a B color LED unit 77B,
An exposure hole 40e for transmitting the light emitted from the G color LED unit 77G is provided. The size and shape of the exposure hole 40e are set according to the size of the print dot.

Further, on both side surfaces 40b of the end surface 40a of the aperture 40, there are formed engagement holes 40d through which the carriage pin 70d is fitted and which engages with the carriage pin 70d. Further, both side surfaces 40 of the end surface 40a of the aperture 40
An insertion hole 40c into which the positioning pin 70c of the carriage 70 is inserted is provided in b. Further, notches are provided on the edge sides of the bent portions, which are the boundaries between the end surface 40a of the aperture 40 and the side surfaces, in order to facilitate bending, and the corner portions of each surface are rounded.

An LED input / output FPC 77f for electrically connecting to the head substrate 77 is provided on the position side of the substrate. Further, on one surface of the head substrate 77, the R color LED unit 77R, the B color LED unit 77B,
Three G-color LED units 77G (9 in total) are arranged side by side in the width direction of the print medium.
In this embodiment, the LED unit 77R, the LED unit 77B, and the LED unit 77G are arranged three by three, but the present invention is not limited to this, and when three or more are arranged according to the size of the printing medium. There is also.

The head substrate 77 has a pair of positioning holes 77c through which the positioning pins 70c of the carriage 70 are inserted.
Is provided. Further, each head substrate 77 has an L
Rectangular storage holes 71R, at the portions (9 locations in this embodiment) corresponding to the ED units 77R, 77G, 77B.
A panel shade 71 having 71B and 71G is overlaid.

Further, the positioning pin 71 of the carriage 70 is inserted into the positioning hole 71c provided in the panel shade 71.
In addition to inserting c, the positioning pin 70c of the carriage 70 is inserted into the hole 40c provided in the aperture 40, and the hole portion 40d provided in the side plate of the aperture 40 is inserted.
Then, the carriage pin 70d is engaged to complete the head portion. In this way, the LED unit 77R, the LED unit 77B, the LED unit 77 on the head substrate 77
G is a storage hole 71R, 71B, 71 of the panel shade 71 held between the head substrate 77 and the aperture 40.
It is assembled in the state of being stored in G.

FIG. 6 is an enlarged vertical sectional view showing the first embodiment of the present invention. FIG. 7 is an enlarged plan view showing the first embodiment of the present invention. As shown in FIGS. 6 and 7, the LED units 77R, LE arranged on the head substrate 77
The D unit 77B and the LED unit 77G have the same structure, and include a light emitting diode 78 as a light emitting element,
The light emitted from the light emitting diode 78 is transmitted through the aperture 40.
And a reflection mirror 80 that focuses the light on the exposure hole 40e.

The light emitting diode 78 is a light emitting element having a narrow directivity (a characteristic that emits light to a narrow range), and LE
A light emitting portion 78a made of D is covered by a shell-shaped case 78b. The light emitting portion 78a is made of, for example, gallium phosphide (Ga).
It is composed of a PN junction diode of an intermetallic compound semiconductor such as P), and emits light by passing an electric current. Then, the light emitted from the light emitting portion 78a projects in a parabolic shape 78b.
The tip of the lens functions as a convex lens, and the angle α (for example,
The light is emitted toward a narrow range of α = 20 ° to 30 °).

In this type of light emitting diode 78, since the light from the light emitting portion 78a does not diffuse laterally, the directivity is strong and the irradiation direction can be concentrated in a certain range. Further, the cannonball-shaped light emitting diode 78 has already been mass-produced, and can be obtained more easily and cheaply than the chip type. Therefore, the LED unit 77
The R, LED unit 77B and LED unit 77G can be manufactured at low cost.

Further, the light emitting diode 78 is mounted on the mounting surface 82a of the supporting portion 82 fixed on the head substrate 77, and the mounting surface 82a of the supporting portion 82 is at a predetermined incident angle β with respect to the reflection mirror 80. Is maintained at a predetermined angle (angle θ with respect to the head substrate 77) so as to maintain

The reflecting mirror 80 has a reflecting surface 84 which reflects the light emitted from the light emitting portion 78a so as to focus the light on the exposure hole 40e of the aperture 40. This reflective surface 84
Is formed in a concave surface that is concave in a hemispherical shape with a predetermined radius of curvature. In this embodiment, the radius r of the Rowland circle 88 formed so that the reflecting surface 84, the center of the light emitting portion 78a (light source position), and the center of the exposure hole 40e are located on the same circumference, The reflecting surface 84 is formed into a concave surface with the curvature of the radius r.

Further, the reflection mirror 80 includes the head substrate 77.
It is attached to the mounting surface 86a of the supporting portion 86 fixed to the upper side, and the mounting surface 86a of the supporting portion 86 has a predetermined angle (the head substrate 77) so that the light from the light emitting diode 78 is focused on the center of the exposure hole 40e. Is attached at an angle δ) with respect to. The light emitting diode 7
The mounting position of 8, the mounting angle (θ) and the mounting position of the reflecting mirror 80, the mounting angle (δ) are the light emitting angle α of the light emitting diode 78, the radius of curvature r of the reflecting mirror 80, the reflecting mirror 80.
It is set according to conditions such as the angle between the center of the exposure hole 40e and the exposure hole 40e.

As a result, the light emitted from the light emitting diode 78 is directed toward the reflection mirror 80, diffracted by the reflection surface 84 thereof, and reaches the center of the exposure hole 40e.
As a result, most of the light emitted from the light emitting portion 78a is reflected on the exposure hole 40e by the reflection mirror 80 and the exposure hole 40e is exposed.
Since the light is focused on e, the amount of light applied to the printing medium 90 can be increased.

Therefore, it is possible to shorten the printing time for irradiating the printing medium 90 with light of each color to develop the color and improve the printing efficiency. Further, when the printing time is the same as the conventional one, the number of LEDs can be reduced by the increase in the amount of light and the manufacturing cost can be kept low.

FIG. 8 is an enlarged vertical sectional view showing a second embodiment of the present invention. FIG. 9 is an enlarged plan view showing a second embodiment of the present invention. In addition, in FIG. 8 and FIG.
The same parts as those in the embodiment are designated by the same reference numerals and the description thereof will be omitted. As shown in FIGS. 8 and 9, in the second embodiment, a surface mount type light emitting diode 92 is used instead of the shell type light emitting diode 78. In this surface mount type light emitting diode 92, a light emitting portion 92a is a hemispherical case 92.
It is molded into b. Then, the light from the light emitting portion 92a is emitted from the lens portion of the case 92b that protrudes in a hemispherical shape.

As described above, the light emitting diode 92 has a compact structure because the case 92b has a small protruding portion. Therefore, the LED unit 77R, the LED unit 77B, and the LED unit 77G can be downsized.

In the case of the second embodiment, as in the case of the first embodiment, the light emitted from the light emitting diode 78 is directed toward the reflection mirror 80, diffracted by the reflection surface 84 thereof, and the light is emitted from the exposure hole 40e. Reach the center. As a result, the exposure hole 40
Most of the light emitted from the light emitting portion 78a is reflected by the reflection mirror 80 and is focused on the exposure hole 40e.
The amount of light applied to the printing medium 90 can be increased.

Therefore, it is possible to shorten the printing time for irradiating the printing medium 90 with light of each color to develop the color and to improve the printing efficiency. Further, when the printing time is the same as the conventional one, the number of LEDs can be reduced by the increase in the amount of light and the manufacturing cost can be kept low.

The reflection mirror 80 may be fixed to the support portion 86 as in the above-described embodiment, or may be rotatably attached so that the reflection direction can be adjusted.

The reflecting surface 84 of the reflecting mirror 80 may be a curved surface having a radius r as described above, or a trapezoidal concave surface 88a having a radius r of curvature of the Rowland circle 88, or a Rowland circle 88. Polygonal shape approximating a concave surface with radius of curvature r (eg octahedron or hexahedron)
It may be formed into a concave surface that is concave.

In the above embodiment, gallium phosphide (Ga)
Although a light emitting diode (LED) made of a PN junction diode made of an intermetallic compound semiconductor such as P) has been described as an example of the light emitting element, the present invention is not limited to this and can be applied to other light emitting elements. .

Further, in the above-mentioned embodiment, the description has been made by using the configuration in which the LED 77R, the LED 77B, and the LED 77G are arranged in the exposing print head 76 by threes, but the present invention is not limited to this. It is needless to say that the present invention can be applied to a structure in which three or more LEDs are arranged or three or less LEDs for each color are arranged.

[0051]

As described above, according to the first aspect of the invention, the aperture having the exposure hole formed at the position facing the printing medium, the light emitting element having the narrow directivity, and the light from the light emitting element are provided. Since the light is emitted from the light emitting element, the light can be efficiently focused on the exposure hole, and the amount of light emitted to the printing medium is increased. It is possible to improve the printing efficiency. Therefore, it is possible to shorten the printing time for irradiating the printing medium with light of each color to develop the color, and to improve the printing speed and the printing efficiency. Further, when the printing time is the same as in the conventional case, the number of light emitting elements can be reduced by the increase in the amount of light, and the manufacturing cost can be kept low.

According to a second aspect of the present invention, the printing apparatus configured to expose the print medium having the photoconductor to light of a specific wavelength by using the print head for the optical printer according to the first aspect to develop color. Therefore, the same action and effect as those of the above-mentioned claim 1 can be obtained.

[Brief description of drawings]

FIG. 1 is an exploded perspective view showing an embodiment of a printing apparatus using a print head for an optical printer according to the present invention.

2 is an exploded perspective view showing a configuration of a drive mechanism of the printing apparatus shown in FIG.

FIG. 3 is an overall configuration diagram of the drive mechanism in FIG.

FIG. 4 is an exploded perspective view mainly showing a heating mechanism.

FIG. 5 is a perspective view of the carriage 70 as viewed from the lower surface side.

FIG. 6 is an enlarged vertical sectional view showing the first embodiment of the present invention.

FIG. 7 is an enlarged plan view showing the first embodiment of the present invention.

FIG. 8 is an enlarged vertical sectional view showing a second embodiment of the present invention.

FIG. 9 is an enlarged plan view showing a second embodiment of the present invention.

FIG. 10 is a graph showing the relationship between wavelength and energy of light emitted from LEDs of each color.

FIG. 11 is an enlarged vertical sectional view showing a conventional print head for an optical printer.

[Explanation of symbols]

40 aperture 40e exposure hole 50 printer 51 upper case 52 media case 53 control board 55 Lower case 60 drive mechanism 61 frames 62 motor 63 Pickup roller 66,73 Guide roller 70 carriage 71 panel shade 71R, 71B, 71G storage holes 72 head drive shaft 75 pressure roller 76 print head 77 Printed circuit board 77R R color LED 77B B color LED 77G G color LED 78,92 Light emitting diode 80 reflective mirror 82,86 support 84 Reflective surface 88 Roland Yen 90 Printing media

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 2C162 AE12 AE23 AE28 AE48 AE77                       FA04 FA17 FA23 FA34 FA49                 2H106 AA12 AA41 AA71 AB10 BG01                       BG08 BG53                 5C051 AA02 CA08 DA05 DB02 DB21                       DB24 DB29 DB31 DC02 DC04                       DC05 DC07

Claims (2)

[Claims] 1. An aperture having an exposure hole formed at a position facing a printing medium, a light emitting element having a narrow directivity, and a reflection mirror for reflecting the light from the light emitting element so as to focus the light on the exposure hole. And a print head for an optical printer, comprising: 2. A printing apparatus, wherein the print head for an optical printer according to claim 1 is configured to expose a print medium having a photoconductor to light of a specific wavelength to develop a color.