JP2000182567A - Fluorescent lamp and fluorescent layer forming method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To achieve uniform brightness over the entire length of a fluorescent lamp. SOLUTION: A fluorescent lamp 23 for fixing light comprises a rodlike glass tube 28 and bases 31, 32 provided at both ends of the glass tube 28. A fluorescent layer 36 is formed at the inner circumferential surface of the glass tube 28. The fluorescent layer 36 is thinnest at an intermediate portion 28a thereof, and becomes thicker toward both ends 28b, 28c thereof. A fluorescent lamp of a straight tube type generally has characteristic of low brightness at both ends thereof. However, the fluorescent lamp 23 is provided with the thick fluorescent layers at both ends thereof, thereby enhancing the brightness at both ends thereof so as to achieve substantially uniform brightness over the entire length.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fluorescent lamp used for a document illuminating device of a copying machine or a scanner, an optical fixing device of a thermal printer, and a method of forming a fluorescent layer of the fluorescent lamp.

[0002]

2. Description of the Related Art As an optical fixing device for a color thermal printer,
A fluorescent lamp (ultraviolet lamp) for irradiating ultraviolet rays is used. A color thermosensitive printer is a color thermosensitive recording paper (hereinafter referred to as a 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 formed on a support. Using,
This prints a full-color image. In this printer, when printing, a thermal head is pressed against recording paper, a yellow image is thermally recorded on the yellow thermosensitive coloring layer having the highest thermal sensitivity, and immediately thereafter, the yellow thermosensitive coloring layer is irradiated with ultraviolet rays to be optically fixed. Next, after a magenta image is thermally recorded on the magenta thermosensitive coloring layer, ultraviolet light is applied to fix the light. Finally, a full-color image is obtained by thermally recording the cyan image on the cyan thermosensitive coloring layer.

In a color thermal printer, a transport roller pair for transporting recording paper, a thermal head, and an optical fixing device for irradiating ultraviolet rays are arranged along a paper supply / discharge direction (sub-scanning direction). . In the printing process, the recording paper is transported in the paper supply / discharge direction by a pair of transport rollers, and during this transportation, a thermal head is used in the width direction (main scanning direction) of the recording paper.
The thermal recording is performed line by line. The optical fixing device uses a fluorescent lamp that emits ultraviolet light, and is arranged along the main scanning direction.

As shown in FIG. 13, a straight tube type fluorescent lamp 71 comprises a rod-shaped glass tube 72 and bases 73 and 74 provided with electrodes at both ends thereof. On the inner peripheral surface of the glass tube 72, a fluorescent layer 76 is formed with a uniform thickness over the entire length. The distribution of the light emission intensity of the fluorescent lamp 71 is substantially flat in the middle part, but has a characteristic of decreasing at both ends. Since the light intensity is insufficient at both ends, a fluorescent lamp 71 sufficiently longer than the width of the recording paper 77 is used.
7 are arranged so as to protrude from the edge.

[0005]

The fluorescent lamp 71 can fix substantially uniformly in the width direction of the recording paper 77. However, since a long fluorescent lamp must be used, the horizontal width of the color thermal printer is required. Has the disadvantage that it becomes larger.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and has as its object to provide a fluorescent lamp having a uniform illuminance over its entire length and a method for forming a fluorescent layer of the fluorescent lamp.

[0007]

According to the present invention, there is provided a fluorescent lamp according to claim 1, wherein the fluorescent layer is formed on the inner surface of a straight tube glass tube. The thickness of the fluorescent layer is increased from the middle part of the tube toward both ends. The fluorescent lamp according to claim 2 is characterized in that the thickness of the fluorescent layer is changed within a range of up to 180 degrees facing the object to be irradiated.

According to a third aspect of the present invention, in the fluorescent lamp, the thickness of the fluorescent layer changes stepwise from the intermediate portion toward the both ends. The fluorescent lamp according to the above, wherein the thickness of the fluorescent layer is, likewise,
It is characterized by continuously changing.

According to a fifth aspect of the present invention, in the case where the fluorescent lamp according to any one of the first to fourth aspects is connected to an unstable potential side of a high-frequency lighting circuit, a fluorescent layer at one end is provided. The thickness is made larger than the end connected to the stable potential side.

In a fluorescent lamp according to a sixth aspect of the present invention, a reflective layer is formed on the inner surface of a glass tube having a straight tube except for a portion where an aperture is formed, and a fluorescent layer is formed on the entire surface of the glass tube from above the reflective layer. In the formed fluorescent lamp, the aperture is wider at both ends.

According to a seventh aspect of the present invention, in the fluorescent lamp according to the sixth aspect, the size of the aperture is continuously increased toward both ends. The fluorescent lamp is characterized in that the size of the aperture is similarly increased stepwise.

According to a ninth aspect of the present invention, in the method of forming a fluorescent layer of a fluorescent lamp, a phosphor solution is poured in a state in which one end of a straight tubular glass is directed downward, and after the phosphor solution solidifies, the other end is lowered. By pouring the phosphor solution again,
It is characterized in that the fluorescent layer is formed so as to become thicker from the middle part of the glass tube toward both ends.

According to a tenth aspect of the present invention, in the method of forming a fluorescent layer of a fluorescent lamp, the fluorescent layer is formed with a uniform thickness from one end to the other end of the glass tube over the entire inner peripheral surface of the rod-shaped glass tube. After the formation, the outer peripheral surfaces of both ends of the glass tube are subjected to masking of a predetermined length, the masked portion is immersed once in a phosphor solution, and then the phosphor is solidified and then masked. And the fluorescent layers at both ends are made thicker.

[0014] In the method of forming a fluorescent layer of a fluorescent lamp according to the present invention, the reflective layer is formed to have a uniform thickness from one end to the other end of the glass tube over the entire inner peripheral surface of the rod-shaped glass tube. After the formation, a part of the reflective layer is scraped off, an aperture having a size larger at both ends is provided, and then, a fluorescent layer is formed on the glass tube.

[0015]

FIG. 2 shows a color thermal printer 2 having a paper feed unit 6 and a print unit 7. A recording paper roll 4 in which a long color thermosensitive recording paper (hereinafter, referred to as recording paper) 3 is wound in a roll shape is set in the paper supply unit 6.

As is well known, the recording paper 3 is provided with a cyan thermosensitive coloring layer, a magenta thermosensitive coloring layer, and a yellow thermosensitive coloring layer in this order on a support. The yellow thermosensitive coloring layer, which is the uppermost layer, has a high thermal sensitivity and develops yellow with small heat energy. The cyan thermosensitive coloring layer, which is the lowermost layer,
It has the lowest thermal sensitivity and develops cyan when a large amount of thermal energy is applied. The recording paper 3 is fed to the printing unit 7 by driving the recording paper roll 4 by the drive motor 8.

The printing section 7 heats the printing paper to emit light from the respective thermosensitive coloring layers.
Platen rollers 13 to 16 for supporting the recording paper 3 in opposition to the thermal heads 9 to 12; transport roller pairs 17 to 20 for transporting the recording paper 3; and yellow light emitting near-ultraviolet light of 420 nm. A fixing device 21 and a light fixing device 22 for magenta that emits near-ultraviolet light of 365 nm.

The transport roller pairs 17 to 20 nip the fed recording paper 3 and transport it in the sub-scanning direction. During this conveyance, each of the thermal heads 9 to 12 and each of the optical fixing units 21 and
2, the recording paper 3 sequentially passes, and a printing process is performed. The recording paper 3 on which the printing process has been completed is cut into a predetermined size by a cutter (not shown), and is discharged out of the printer 2.

Each of the thermal heads 9 to 12 has a heating element array 9a to 12 in which a large number of heating elements are arranged in a line.
a is provided. The heating element arrays 9a to 12a
Extend in the width direction of the recording paper 3 (main scanning direction). Thermal recording is performed on a line along this direction.

The thermal heads 9 to 12 are arranged in order from the paper supply side for yellow thermosensitive layer coloring, magenta thermosensitive layer coloring,
For cyan thermosensitive layer coloring. The heat generation energy of the thermal head 9 for yellow is the lowest and the thermal head 12 for cyan is the highest. Each of these thermal heads 9-1
A full-color image is obtained by the thermal recording of the two three-color planes sequentially.

The yellow light fixing device 21 is located downstream of the yellow thermal head 9, and the magenta light fixing device is
They are arranged downstream of the magenta thermal head 11, respectively. The light fixing is performed on the yellow thermosensitive coloring layer and the magenta thermosensitive coloring layer on which the thermal recording has been performed by the thermal heads 9 and 11. The cyan thermosensitive coloring layer is located at the lowermost layer of the thermosensitive layer and does not undergo color fixation at the time of recording, so that light fixing is not performed. Of course, the cyan thermosensitive coloring layer may be provided with a light fixing property.

Each of the fixing units 21 and 22 is composed of a straight tube type fluorescent lamp 23 and 24, and reflectors 26 and 27. Each of the fluorescent lamps 23 and 24 is driven by a lighting circuit 30. As shown in FIG. 1, the fluorescent lamp 23 for yellow comprises a glass tube 28 and caps 31 and 32 provided at both ends thereof. This fluorescent lamp 23
The glass tube 28 is arranged along the width direction of the recording paper 3 so that the middle portion 28a of the glass tube 28 is located at the center of the recording paper 3 in the width direction.

A fluorescent layer 36 of a fluorescent material is formed on the inner peripheral surface of the glass tube 28 over the entire circumference. The fluorescent layer 36 is formed so that the thickness of the intermediate portion 28a is the thinnest and becomes thicker toward both end portions 28b and 28c. Since the luminous intensity increases in proportion to the thickness of the fluorescent layer 36, the luminous intensity at both ends 28b and 28c becomes higher than that of the conventional one, and the luminous intensity in the width direction of the recording paper 3 becomes uniform. Further, both ends 28b and 28c of the fluorescent lamp 23 can be used for light fixing, so that the tube length can be shortened. The same applies to the magenta fluorescent lamp 24.

In the color thermal printer 2 shown in FIG. 2, when a print instruction is given, the recording paper roll 4 rotates via a drive motor 8 and paper is supplied to a print unit 7. The fed recording paper 3 is nipped by transport rollers 17 to 20 and transported in the print unit 7. During this transfer,
The thermal head 13 for yellow performs thermal recording. During this thermal recording, the fluorescent lamp 23 of the yellow light fixing device 21 is used.
Lights up to perform light fixing of the yellow thermosensitive coloring layer.

Since the fluorescent layer 36 is applied to both ends 28b and 28c of the glass tube 28 so as to be thicker than the intermediate portion 28a, the recording paper 3 extends from the center to both ends.
Receives ultraviolet light with uniform emission intensity. For this reason, the integrated amount of ultraviolet light received by the recording paper 3 during conveyance becomes substantially uniform in the width direction. As a result, there is no fixing unevenness.

When the thermal recording and the optical fixing of the yellow thermosensitive coloring layer are completed, the thermal recording is performed by the magenta thermal head 11, and then the optical fixing is performed by the magenta optical fixing device 22. Optical fuser 2 for yellow
As in the case of No. 1, light fixing is also performed on the magenta thermosensitive coloring layer without fixing unevenness.

When the thermal recording and the optical fixing of the magenta thermosensitive coloring layer are completed, the thermal head 12 for cyan uses
Thermal recording of the cyan thermosensitive coloring layer is performed. The printed recording paper 3 on which the full-color image has been recorded is cut into a predetermined size and discharged out of the printer 2.

The fluorescent lamp 23 shown in FIG. 1 has a fluorescent layer formed by the method shown in FIG. First, in the phosphor pouring step, the phosphor solution 35 is poured from one end of the transparent glass tube 28 while rotating the transparent glass tube 28 in a slightly inclined state, and flows down the inner surface of the glass tube 28. next,
In the vertical coagulation step, the glass tube 28 is set upright with the end 28b downward, and the phosphor solution 35 is coagulated in this state. In this step, the phosphor solution 35 flows toward the end 28b by gravity, so that the end 28
The thickness t2 on the b side is larger than the thickness t1 of the intermediate portion 28a. When the phosphor pouring step and the vertical solidification step are repeated with the end portion 28c side downward, the end portion 28c also becomes thicker. As a result, the fluorescent layer 36 is formed so as to be continuously thicker from the intermediate portion 28a toward both ends 28b and 28c.

The thickness of the fluorescent layer may be increased stepwise, for example, as in a fluorescent lamp 41 shown in FIG.
Such a fluorescent layer 40 is formed by the method shown in FIG. First, in the phosphor base film forming step, the phosphor solution 3
By spraying 5 into the glass tube 42 by spraying or the like,
The base film 40a having a uniform thickness (t1) is formed. Next, in a masking step, both ends 4 of the glass tube 42 are formed.
2b and 42c are masked with a tape 44. Next, in the end coating step, one end 42 b is inserted into the phosphor solution 35. Since a masking tape is attached to the outer peripheral surface of the end 42b, the phosphor solution 35 is applied only to the inner peripheral surface. Then, this operation is also performed on the other end 42c. After the phosphor solution 35 solidifies, the tape 44 is peeled off in a masking removal step.

As a result, the thickness t2 of both ends 42b and 42c is formed in a step-like shape which is thicker than the thickness t1 of the intermediate portion 42a. If the above steps are repeated while the masking tape is gradually shortened, a tape having a plurality of steps of thickness can be formed.

The thickness of the fluorescent layer may not be the same at both ends, and may be different at both ends 47b and 47c of the glass tube 47 like the fluorescent layer 45 of the fluorescent lamp 46 shown in FIG. It may be different. The thickness t2 of the end 47b and the end 47c
Are formed thicker than the thickness t1 of the intermediate portion 47a, respectively, while t2 is formed slightly thinner than t3. The fluorescent lamp 46 of this example is used by being connected to, for example, a high-frequency lighting circuit 48. The high frequency lighting circuit 48 has an unstable potential side and a stable potential side, and the fluorescent lamp 46 has its electrodes connected to the unstable potential side socket 51 and the stable potential side socket 52, and performs high frequency lighting. .

In this case, more emitters (electron emitting materials) are generated in the electrode connected to the unstable potential side socket 51 than in the electrode connected to the stable potential side socket 52. As a result, a blackening phenomenon occurs on the inner wall of the glass tube 47, and the transmittance at that portion decreases. If the thick end 47c of the fluorescent layer 45 is connected to the unstable potential side socket 51, the blackening of the glass tube 47 becomes difficult to be seen from the outside, and as a result, a local decrease in transmittance can be suppressed. it can.
The shape of the fluorescent layer may have a stepwise change in thickness, such as the fluorescent layer 50 formed on the glass tube 53 shown in FIG. 6B.

In each of the above embodiments, the change in the thickness of the fluorescent layer is described over the entire circumference of the inner peripheral surface of the glass tube. As shown in FIG. 7 and FIG. 8, a change may be given to a part.

The fluorescent layers 54 and 58 are formed on the glass tubes 56 and 57 over the entire inner peripheral surface thereof. Of these, the change in the thickness of the fluorescent layers 54 and 58 depends on the glass tubes 56 and
57 is given only to portions corresponding to the facing surfaces 56d and 57d facing the recording paper 3. Such a fluorescent layer 5
The formation of the layers 4 and 58 is performed by masking a part of the inner peripheral surface and then applying the above-described respective fluorescent layer forming methods. As a result, a change in the thickness of the fluorescent layers 54 and 58 is given only to the unmasked portions. The facing surfaces 56d and 57d extend over a maximum range of 180 degrees, but may be smaller, for example, about 120 degrees.

FIG. 9 shows a glass tube of a fluorescent lamp in which the size of the aperture through which ultraviolet light is transmitted is widened at both ends. The glass tube 62 shows an example in which a fluorescent layer 63 is formed on an ultraviolet reflecting layer 61. Further, in the glass tube 62 of this example, as shown in FIG. 9B, an aperture 64 on which the reflection layer 61 is not formed is provided on a part of the facing surface 62d, and ultraviolet light is irradiated from this part. Is done.

The aperture 64 allows the glass tube 6
Since the ultraviolet light generated inside 2 can be condensed toward the recording paper 3, the irradiation efficiency is improved.
Further, since the width of the aperture 64 is formed so as to increase from the intermediate portion 62a to both end portions 62b, the integrated light amount becomes uniform in the width direction of the recording paper 3.

FIG. 10 shows a glass tube 66 used in a fluorescent lamp in which both the size of the aperture and the thickness of the fluorescent layer are changed. On the inner peripheral surface of the glass tube 66, a reflection layer 61 and a fluorescent layer 67 are formed as in the case of the glass tube 62 (FIG. 9). In the glass tube 66, its facing surface 66d
The width of the aperture 68 formed in the
In addition, the fluorescent layer 67 is formed so as to increase in width from a to both end portions 66b, and also to be thicker.

According to this, the width of the aperture 68 and
By combining the change in the thickness of the fluorescent layer 67, the integrated light amount can be adjusted. Therefore, for example, the same effect as the glass tube 62 (FIG. 9) can be obtained while suppressing both the change in the width of the aperture 68 and the thickness of the fluorescent layer 67. The shape of the aperture is, as shown in the aperture 65 of the glass tube 69 shown in FIG.
It may be gradually expanding.

The formation of the fluorescent layers of these glass tubes 62, 66, 69 is performed by the method shown in FIG. First, in the reflector applying step, the reflector solution is applied uniformly over the entire inner peripheral surface of the glass tube 69 to a thickness (t1) to form the reflective layer 61. Next, in the reflector scraping step, a part of the reflecting layer 61 is scraped, and the aperture 65 is formed on the facing surface 69d. In this state,
It is sent to the above-mentioned phosphor application step, and the phosphor layer is laminated. The same applies to the glass tubes 62 and 66.

In the above embodiment, the fluorescent lamp of the present invention has been described as being applied to an optical fixing device of a color thermal printer. However, the fluorescent lamp is used as an illuminating device for illuminating a document of a copier or a scanner, and emits visible light. Also applicable to fluorescent lamps.

[0041]

As described in detail above, the fluorescent lamp of the present invention has a fluorescent layer formed over the entire inner peripheral surface of the glass tube of the fluorescent lamp. On the inner periphery of the surface facing the paper or document, the thickness of the fluorescent layer is formed so as to increase from the middle to both ends, so that the emission intensity is reduced over the entire length of the fluorescent lamp. It can be uniform. In addition, since the emission intensity at both ends has been increased, both ends can be used effectively,
Thereby, the length of the fluorescent lamp can be shortened.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing a fluorescent lamp in which the thickness of a fluorescent layer is continuously increased toward both ends and the emission intensity of the lamp.

FIG. 2 is an explanatory view schematically showing a color thermal printer implementing the fluorescent lamp of the present invention.

FIG. 3 is an explanatory diagram showing a procedure for forming a fluorescent layer of the fluorescent lamp shown in FIG. 1;

FIG. 4 is an explanatory diagram showing a fluorescent lamp in which the thickness of a fluorescent layer is gradually increased toward both ends and the emission intensity of the lamp.

FIG. 5 is an explanatory view showing a procedure for forming a fluorescent layer of the fluorescent lamp shown in FIG. 4;

FIG. 6 is an explanatory diagram showing a fluorescent lamp in which a fluorescent layer at the other end is thicker than one end and a lighting circuit thereof.

FIG. 7 is an explanatory view showing a fluorescent lamp in which the thickness of a fluorescent layer is continuously changed only on one side of a glass tube.

FIG. 8 is an explanatory view showing a fluorescent lamp in which the thickness of a fluorescent layer is changed stepwise only on one side of a glass tube.

FIG. 9 is an explanatory diagram showing a fluorescent lamp in which the size of the aperture is changed between the center and both ends.

FIG. 10 is an explanatory view showing a fluorescent lamp in which the thickness of the fluorescent layer and the size of the aperture are changed.

FIG. 11 is an explanatory view showing a fluorescent lamp in which the size of the aperture is changed stepwise.

FIG. 12 is an explanatory view showing an aperture forming procedure of the fluorescent lamp shown in FIGS. 9, 10 and 11;

FIG. 13 shows a conventional fluorescent lamp having a uniform thickness of a fluorescent layer,
It is explanatory drawing which shows the light emission intensity of this lamp.

[Description of Signs] 23, 24, 41, 46, 71 Fluorescent lamps 28, 42, 47, 56, 57, 62, 66, 69, 7
2 Glass tube 36, 40, 45, 54, 58, 63, 67, 76 Fluorescent layer 35 Phosphor solution 61 Reflective layer 64, 65, 68 aperture

Continuation of the front page F term (reference) 5C028 EE02 EE17 5C043 AA02 AA04 BB03 BB09 CC09 CD01 DD28 DD31 DD39 EA11 EA14

Claims (11)

[Claims] 1. A fluorescent lamp in which a fluorescent layer is formed on the inner surface of a glass tube having a straight tube shape, wherein the thickness of the fluorescent layer is increased from an intermediate portion of the glass tube toward both ends. 2. The fluorescent lamp according to claim 1, wherein the thickness of the fluorescent layer is changed within a maximum range of 180 degrees facing the object to be irradiated. 3. The fluorescent lamp according to claim 1, wherein the thickness of the fluorescent layer changes stepwise from the intermediate portion toward the both ends. 4. The fluorescent lamp according to claim 1, wherein the thickness of the fluorescent layer continuously changes from the intermediate portion to the both end portions. 5. The fluorescent layer according to claim 1, wherein one end of the high-frequency lighting circuit connected to the unstable potential side has a thickness of the fluorescent layer larger than that of the end connected to the stable potential side.
The fluorescent lamp described in any one of the above. 6. A fluorescent lamp in which a reflection layer is formed on the inner surface of a glass tube having a straight tube shape except for a portion where an aperture is formed, and a fluorescent layer is formed on the entire circumference of the glass tube from above the reflection layer. The fluorescent lamp is characterized in that the aperture is wider at both ends. 7. The fluorescent lamp according to claim 6, wherein the size of the aperture increases continuously toward both ends. 8. The fluorescent lamp according to claim 6, wherein the size of the aperture gradually increases toward both ends. 9. A phosphor solution is poured in a state in which one end of the straight glass tube is directed downward, and after the phosphor solution has solidified, the phosphor solution is poured again with the other end directed downward, From the middle part of the glass tube toward both ends,
A method for forming a fluorescent layer of a fluorescent lamp, wherein the fluorescent layer is formed to be thick. 10. A fluorescent layer having a uniform thickness from one end to the other end of the glass tube over the entire inner peripheral surface of the rod-shaped glass tube. The surface is masked for a predetermined length, the masked portion is immersed once in a phosphor solution, and then the mask is peeled off after solidifying the phosphor, and the phosphor layers at both ends are thickened. A method for forming a fluorescent layer of a fluorescent lamp. 11. A reflective layer having a uniform thickness from one end to the other end of the glass tube over the entire inner peripheral surface of the rod-shaped glass tube, and a part of the reflective layer is cut off. A method of forming a fluorescent layer in a fluorescent lamp, comprising: providing an aperture whose size is larger at both ends, and thereafter forming a fluorescent layer on the glass tube.