JP2003237126A - Plane light source device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To make compact a plane light source device for irradiating a plurality of kinds of light. <P>SOLUTION: A plasma display panel having a flat light-emitting panel is used as a light fixing device of a color thermal printer. Phosphors 24a for emitting a fixing light for yellow and phosphors 24b for emitting a fixing light for magenta are alternately arranged in a staggering manner on the plasma display panel. These phosphors selectively emit light at a light fixing time of yellow and magenta. The device is made small by making the light emitting panel one. Moreover, since an area ratio of a light emitting part of each of phosphors 24a and 24b to the whole of a light emitting face is reduced, a power density (electric energy supplied for unit area) is lowered. Heating of the light emitting face is suppressed accordingly, and a heat sink member and the like can be made small thereby. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flat light source device including a flat light emitting panel for irradiating an object to be illuminated with a plurality of types of light.

[0002]

2. Description of the Related Art A flat light source device having a flat light emitting panel such as a plasma display panel is known. The flat light source has a good light distribution and is capable of uniformly irradiating an irradiation target with light, and therefore, for example, JP-A-2000-177155 and JP-A-2000-18.
Japanese Patent No. 5418 describes a color thermal printer using a plasma display panel as an optical fixing device. A color thermal printer prints a full-color image using a color thermosensitive recording paper in which at least three types of thermosensitive coloring layers, for example, a cyan thermosensitive coloring layer, a magenta thermosensitive coloring layer, and a yellow thermosensitive coloring layer are sequentially laminated on a support. To do.

Each of the yellow and magenta thermosensitive coloring layers is provided with a photo-fixing property by light of a specific wavelength range. The wavelength of the yellow thermosensitive coloring layer is about 420 nm.
When the fixing light for Y (yellow), which is a blue-violet light in the vicinity, is irradiated, the light is fixed. On the other hand, the magenta thermosensitive coloring layer is irradiated with fixing light for M (magenta), which is near-ultraviolet light having a wavelength of about 365 nm. Light fixed.

The optical fixing device comprises a yellow light emitting panel coated with a phosphor emitting Y fixing light and a magenta light emitting panel coated with a phosphor emitting M fixing light. The light emitting panels are arranged side by side on the transport path. The optical fixing device is used for color thermosensitive recording paper.
By selectively irradiating each fixing light from each light emitting panel, each of the heat-sensitive yellow and magenta thermosensitive coloring layers which have been thermally recorded are optically fixed.

[0005]

However, since the conventional optical fixing device is provided with two light emitting panels for yellow and magenta separately, it has been an obstacle in reducing the size of the printer body. . It is known that when the temperature of the phosphor increases, not only the luminous efficiency decreases, but also the phosphor progresses and the life of the phosphor decreases. Therefore, if the applied voltage is increased to increase the light emission amount, the light emission efficiency and the life of the phosphor are sacrificed. Therefore, in order to cool the light emitting surface, a large heat dissipation member or the like is required, which causes a problem that the size is further increased.

The present invention has been made in consideration of the above problems, and an object thereof is to miniaturize a flat light source device for irradiating a recording paper with plural kinds of light.

[0007]

In order to achieve the above object, the flat light source device of the present invention is a flat light emitting device for selectively irradiating a conveyed recording paper with a plurality of kinds of light having different wavelength ranges. In the flat light source device including a panel, a plurality of types of light emitting elements that emit the plurality of types of light are alternately arranged in a staggered pattern on the light emitting panel.

Another flat light source device of the present invention is a flat light source device comprising a flat light emitting panel for selectively irradiating a conveyed recording paper with a plurality of types of light having different wavelength ranges. In the light emitting panel, a plurality of types of light emitting element rows that emit the plurality of types of light are alternately arranged so as to form a stripe. In this light emitting panel, the longitudinal direction of each of the light emitting element rows is the recording paper. It is characterized in that it is arranged along the width direction of.

The light emitting element is made of a phosphor that emits light when excited by an electron beam.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A color thermal printer 2 shown in FIG.
Performs thermal recording of a full-color image and optical fixing of the thermally recorded color thermosensitive recording paper 3 while conveying the color thermosensitive recording paper 3 back and forth in the forward direction and the reverse direction.

The color thermosensitive recording paper 3 has at least three thermosensitive coloring layers on a support, a yellow thermosensitive coloring layer for yellow, a magenta thermosensitive coloring layer for magenta, and a cyan thermosensitive coloring layer for cyan. It is stacked. The thermosensitive coloring layers are yellow, magenta,
The layers are arranged in the order of cyan, and the lower thermosensitive coloring layer has lower thermal sensitivity.

Further, the yellow thermosensitive coloring layer and the magenta thermosensitive coloring layer below the yellow thermosensitive coloring layer are provided with fixability by light in respective wavelength regions. The yellow thermosensitive coloring layer is photo-fixed when irradiated with Y fixing light having a wavelength of about 420 nm, while the magenta thermosensitive coloring layer has a wavelength of about 3
When the fixing light for M near 65 nm is irradiated, the light is fixed.

A recording paper roll 4 obtained by winding a color thermal recording paper 3 in a roll is set on the color thermal printer 2. The recording paper roll 4 is rotated by the driving of the paper feed roller 5 and feeds the color thermosensitive recording paper 3 onto the conveying path.

A thermal head 6 and a platen roller 7 that faces the thermal head 6 and supports the color thermosensitive recording paper 3 are disposed on the conveying path. As is well known, the thermal head 6 includes a heating element array 6a in which a large number of heating elements are arranged in a line along the main scanning direction. The heating element array 6a is pressed against the color thermosensitive recording paper 3 for thermal recording. Each heat generating element generates heat energy according to the density of the pixel, yellow, magenta,
An image of each color of cyan is thermally recorded on each thermosensitive coloring layer.

On the downstream side of the thermal head 6 in the forward direction, a pair of conveying rollers 8 and an optical fixing device 9 are arranged. The conveyance roller pair 8 nips the fed color thermosensitive recording paper 3 and conveys it in the sub-scanning direction.

During this conveyance, the color thermal recording paper 3 passes through the thermal head 6 and the optical fixing device 9 to perform thermal recording and optical fixing. The color thermosensitive recording paper 3 on which the thermal recording and the optical fixing have been completed is cut into a sheet of a predetermined size by a cutter (not shown) and is discharged to the outside of the color thermosensitive printer 2.

As the carry motor, for example, a pulse motor that rotates a predetermined amount according to the number of given drive pulses is used. When the photo sensor 12 detects the leading edge of the color thermosensitive recording paper 3 during paper feeding, counting of drive pulses is started. By counting up and down this drive pulse, the carry amount in the forward direction and the reverse direction is controlled.

The optical fixing device 9 is a plasma display panel (PDP) 16 having a flat light emitting panel as a light source.
Is used, and the light emitting surface 16a is arranged so as to face the recording surface of the color thermosensitive recording paper 3.

2 and 3 are a fragmentary sectional view and an internal plan view showing a schematic structure of the PDP 16. The outside of the PDP 16 has a front glass substrate 22 from which light is emitted and a rear glass substrate 2 arranged behind the front glass substrate 22.
3 and 3.

Back glass substrate 23 of front glass substrate 22
A cathode 22a formed by thick film printing of nickel, aluminum paste, or the like is provided on the surface facing to. On the inner surface of the back glass substrate 23, an anode 23a is formed by thick film printing with nickel, aluminum paste or the like, and a large number of phosphors 24 forming a light emitting element are formed on the anode 23a. These phosphors 24 are applied by thick film printing, and a hole for a discharge anode is provided in the center of each phosphor 24. Further, between the respective anodes 23a, partition walls 26 having a thick film of about 200 μm are formed so as to divide dots by performing overprinting several times by thick film printing.

In the front glass substrate 22 and the rear glass substrate 23, the cathode 22a and the anode 23a are orthogonal to each other, and
anode 23a in which a is exposed through the hole of each phosphor 24
Aligned so that it overlaps with the top, and the perimeter is sealed.
In addition, the cathode 22a and the cathode 23 formed by the partition wall 26
A mixed gas of He-Xe, He-Kr, or the like is sealed in the space between a and a. When a voltage is applied to the anode 23a, discharge occurs at the intersection of the anode 23a and the cathode 22a, and each phosphor 24 is excited to emit light by irradiation with an electron beam.

FIG. 4 shows the arrangement of the phosphors 24 on the inner surface of the rear glass substrate 23. The phosphor 24 is composed of two types of phosphors, a yellow phosphor 24a that emits Y fixing light with an emission peak of 420 nm and a magenta phosphor 24b that emits M fixing light with an emission peak of 365 nm. Become. These phosphors 24a and 24b are arranged alternately in a zigzag pattern.

The respective fixing lights for Y and M are selectively emitted. That is, the light source control unit 2 that controls the PDP 16
8 (see FIG. 1), when fixing the yellow thermosensitive coloring layer, a voltage is applied to the electrode corresponding to each yellow phosphor 24a to emit the Y fixing light. On the other hand, when fixing the magenta thermosensitive coloring layer, a voltage is applied to the electrode corresponding to the magenta phosphor 24b to emit the M fixing light.

As described above, two types of phosphors 24a and 24b for yellow and magenta are formed on one light emitting panel, and these two types of fixing light are selectively irradiated, so that Y and The optical fixing device can be downsized as compared with the case where each fixing light for M is emitted from each separate light emitting panel. In addition, since the number of the phosphors 24a and 24b arranged in the sub-scanning direction is the same in the main scanning direction, the light amount distribution in the main scanning direction becomes uniform and uneven fixing does not occur.

Further, since the two types of phosphors 24a and 24b for yellow and magenta arranged in a zigzag pattern selectively emit light, when one emits light, the other does not emit. Therefore, if the area of the light emitting portion (the area of one light emitting portion of yellow or magenta) is the same as in the case where one type of phosphor is arranged without a gap,
By arranging in a staggered pattern, the area of the entire light emitting surface 16a (the area including the light emitting portions of both yellow and magenta)
Is doubled, and the power density (the amount of power supplied per unit area) is halved.

Therefore, the heat generation density of the light emitting surface 16a is lowered, and the temperature rise of the phosphor 24 is suppressed. For this reason,
The increase in temperature of the phosphor 24 does not reduce the luminous efficiency or shorten the life of the phosphor 24.

The amount of light emission is controlled by adjusting the applied voltage. By arranging the two types of phosphors in a staggered pattern, the power density was halved compared to the conventional one.
Even if the applied voltage is doubled, the luminous efficiency decreases,
The deterioration of the phosphor is not accelerated. Light emitting surface 16
Even when a heat dissipation member or the like is provided in order to suppress the temperature rise of a, the size can be reduced due to the decrease in power density.

The operation of the above configuration will be described below. When printing with the color thermal printer 2, first, the recording paper roll 4 is set and a print instruction is given.
When a print instruction is issued, the color thermosensitive recording paper 3 is fed on the conveying path. The thermal head 6 thermally records a yellow image on the yellow thermosensitive coloring layer. The thermally recorded portion of the color thermosensitive recording paper 3 is sequentially sent to the optical fixing device 9.

At the time of fixing the yellow color, a voltage is applied to the electrode corresponding to the yellow phosphor 24a by the control of the light source controller 28, and the yellow phosphor 24a emits light.
As a result, the fixing light for Y is emitted from the light emitting surface 16a,
The heat-recorded yellow thermosensitive coloring layer is optically fixed. Since the magenta phosphor 24b does not emit light when the yellow phosphor 24a emits light, the power density of the light emitting surface 16a is small. As a result, the temperature rise of the yellow phosphor 24a can be suppressed, so that the emission efficiency does not decrease and the phosphor does not deteriorate quickly.

When the thermal recording and the optical fixing of yellow are completed, the color thermal recording paper 3 is once rewound and then conveyed again in the forward direction to thermally record the magenta image.

At the time of fixing magenta, a voltage is applied to the electrode corresponding to the magenta phosphor 24b under the control of the light source control section 28, and the magenta phosphor 24b emits light.
As a result, M fixing light is emitted from the light emitting surface 16a,
The magenta thermosensitive coloring layer on which heat recording has been completed is optically fixed. Since the magenta phosphors 24b are also arranged in a staggered manner like the yellow phosphors 24a, the power density of the light emitting surface 16a is small. Therefore, the luminous efficiency is not lowered and the phosphor is not deteriorated quickly.

When the magenta thermal recording and the optical fixing are completed, the color thermosensitive recording paper 3 is rewound again and conveyed again in the forward direction. A cyan image is thermally recorded during this conveyance. When the thermal recording of the cyan image is completed, the recorded portion of the color thermosensitive recording paper 3 is cut into sheets and ejected.

In the above-described embodiment, the example in which the yellow and magenta phosphors are alternately arranged in a zigzag pattern has been described.
Like the PDP 31 shown in FIG. 5, the yellow and magenta phosphors 24a and 24b are arranged in a line.
The phosphor columns 32 and 33 may be arranged alternately so as to form stripes. The PDP 31 is arranged such that the phosphor rows 32 and 33 are along the main scanning direction orthogonal to the carrying direction (sub-scanning direction), that is, the width direction of the color thermosensitive recording paper 3. By doing so, the light amount distribution in the main scanning direction becomes uniform.

The yellow and magenta phosphor arrays 32 and 33 selectively emit light. Even in this case, since the area of the entire light emitting surface 16a with respect to the light emitting portion is increased, the same effect as in the case of staggered arrangement can be obtained.

Further, as shown in FIG. 6, a light emitting diode (LED) 41 may be used as a light emitting element instead of the phosphor, and a light emitting element array 42 in which these are arranged may be used as a light emitting panel. In this case, the yellow LEDs 41a and the magenta LEDs 41b are alternately arranged in a staggered pattern. Further, like the light emitting element array 43 shown in FIG. 7, each of the LEDs 41a and 41b may be arranged in a line, and the respective LED rows 46 and 47 may be arranged alternately so that they form a stripe. . Light emitting element array 4
3 is arranged so that the LED rows 46 and 47 are along the main scanning direction.

As another plane light source, a CRT (Cath
ode Ray Tube, VFD: Vacuum Fluores
cent Display), FED (Field Emission Display),
There are organic EL (Electro Luminescence) and the like, but the present invention can be applied to any of these.

In the above embodiment, an example in which two kinds of light are selectively emitted from one light emitting panel has been shown.
It can also be applied to the case of selectively irradiating more than one kind of light.

In the above embodiment, the flat light source device of the present invention is used as an optical fixing device of a color thermal printer. However, the present invention is not limited to this. It can also be applied to an optical fixing device used in a light and heat sensitive printer described in Japanese Patent Laid-Open No. 2000-221674.

[0039]

As described in detail above, the present invention is
In a flat light source device including a flat light emitting panel for selectively irradiating a conveyed recording paper with a plurality of kinds of light having different wavelength ranges, in the light emitting panel, a plurality of kinds of light emitting a plurality of kinds of light are emitted. The light emitting elements are alternately arranged in a zigzag pattern, and the plurality of types of light emitting element rows that emit the plurality of types of light are alternately arranged in the light emitting panel so as to form a stripe. Since the longitudinal direction of each light emitting element row is arranged along the width direction of the recording paper, the size can be reduced.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a color thermal printer.

FIG. 2 is an internal cross-sectional view of a plasma display.

FIG. 3 is an internal plan view of the plasma display.

FIG. 4 is an explanatory diagram showing an example in which a plurality of types of phosphors are alternately arranged in a staggered pattern.

FIG. 5 is an explanatory diagram showing an example in which a plurality of types of phosphors are alternately arranged in a stripe shape.

FIG. 6 is an explanatory diagram showing an example in which a plurality of types of LEDs are alternately arranged in a staggered pattern.

FIG. 7 is an explanatory diagram showing an example in which a plurality of types of LEDs are alternately arranged in a stripe shape.

[Explanation of symbols]

2 color thermal printer 3 color thermal recording paper 9 Optical fixing device 16 light sources 16a light emitting surface 28 Light source control unit 24 phosphor 24a Yellow phosphor 24b Magenta phosphor 41 LED 41a Yellow LED 41b Magenta LED

Continued front page    F-term (reference) 2C162 AE12 AE25 AE28 AF01 AF06                       AF07 AF61 FA02 FA17 FA19                       FA34

Claims (3)

[Claims] 1. A flat light source device comprising a flat light emitting panel for selectively irradiating a conveyed recording paper with a plurality of kinds of light having different wavelength regions, wherein the light emitting panel has a plurality of kinds of light. A planar light source device, characterized in that a plurality of types of light emitting elements for emitting light are alternately arranged in a staggered pattern. 2. A flat light source device comprising a flat light emitting panel for selectively irradiating a conveyed recording paper with a plurality of kinds of light having different wavelength ranges, wherein the light emitting panel has a plurality of kinds of light. A plurality of types of light emitting element rows that emit light are alternately arranged to form a stripe, and the light emitting panel is arranged such that the longitudinal direction of each of the light emitting element rows is along the width direction of the recording paper. A flat light source device. 3. The flat light source device according to claim 1, wherein the light emitting element is made of a phosphor that excites and emits light when irradiated with an electron beam.