JP2004184478A - Flash fixing device and flash lamp - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a flash lamp having a cylindrical flash tube and trigger electrodes disposed on the peripheral face of the flash tube and substantially in parallel with the axis of the flash tube and to a flash fixing device using the flash lamp, wherein the flash fixing device and flash lamp have no density nonuniformity. <P>SOLUTION: A flash lamp 55 includes: a cylindrical flash tube 57; a first trigger electrode 61 and a second trigger electrode 63 that are disposed on the peripheral face of the flash tube 57 and substantially in parallel with the axis of the flash tube 57. The first trigger electrode 61 and the second trigger electrode 63 are disposed at an angle of 0°±30° and at an angle of 180°±30°, respectively, having as a reference an intersection where a straight line parallel to a face that passes through the axis on the cross-section of the flash tube 57 perpendicular to the axis of the flash tube 57 and has the toner image of a medium formed thereon, and the peripheral face of the flash tube 57. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a flash lamp having a cylindrical arc tube and a trigger electrode disposed on an outer peripheral surface of the arc tube substantially in parallel with the axis of the arc tube, and a flash fixing device using the flash lamp. About.
[0002]
[Prior art]
First, a conventional flash fixing device will be described with reference to FIG.
[0003]
In the figure, a medium 3 having an image formed by toner 1 on the upper surface is conveyed at a constant speed in the direction of the arrow in the figure.
[0004]
The flash lamp 5 is provided with a main electrode at both ends, a luminous tube 7 in which a rare gas such as xenon (Xe) gas is sealed, and a flash lamp 5 which is disposed on the outer peripheral surface of the luminous tube 7 and discharges between the main electrodes. At the time of starting, it consists of one trigger electrode 9 to which a high voltage is applied.
[0005]
A reflector 11 is provided around the flash lamp 5 to reflect light from the flash lamp 5 toward the medium 3. Further, a glass 13 is disposed between the flash lamp 5 and the medium 3 in order to prevent the unfixed toner 1 scattered from attaching to the flash lamp 5 (for example, see Patent Document 1).
[0006]
The operation of the above configuration will be described.
[0007]
When a pulsed high voltage is applied to the trigger electrode 9 of the flash lamp 5, dielectric breakdown occurs in the rare gas in the arc tube 7 along the trigger electrode 9, and arc discharge occurs between the main electrodes of the arc tube 7. Generates and emits light. The toner 1 on the medium 3 is melted by the radiant heat of this light emission (also called flash light), and fixing is performed.
[0008]
Since the flash lamp 5 emits light only when a pulsed high voltage is applied to the trigger electrode 9, the light emission is intermittent.
[0009]
[Patent Document 1]
JP-A-7-13457 (pages 2 to 4, FIGS. 1, 2 and 5)
[0010]
[Problems to be solved by the invention]
Conventionally, high-speed printing apparatuses generally have a low resolution (about 240 dpi (dot / 25.4 mm)), but recently, high-speed printing apparatuses have also been required to improve image quality and output image images. , High resolution (600 dpi or more) is required.
[0011]
However, in a flash fixing device that fixes a toner image by flash light, when a halftone image having a resolution of 600 dpi or more is fixed, unevenness in density becomes evident, which hinders high image quality.
[0012]
Here, a result obtained by printing a line in the sub-scanning direction of 1on1off at a resolution of 600 dpi by a printer using a flash fixing device having a configuration as shown in FIG. 9 is measured by a densitometer, and the result is quantified into emission energy. It is shown in FIG.
[0013]
As shown in the figure, there is an energy difference between a portion where the flash light overlaps and a portion where the flash light does not overlap once, and density unevenness occurs.
[0014]
On the other hand, as shown in FIG. 11, the reflection plate 11 is set such that the emission energy distribution in the transport direction (w) of the medium 3 irradiated by one flash is as follows.
[0015]
In other words, the distribution of g (x) and g ′ (v / f + x), which is substantially constant at the center and decreases as the distance to both sides increases, is β, the energy at which the physical properties of the toner start irreversible change. When the emission frequency is f [Hz], the medium conveyance speed is v [mm / s], and the emission energy unevenness is δ [%],
g (x) + g ′ (v / f + x) −β = f (x) + δ (1)
Each value is set so that the following holds. Note that δ = ± 7.0%.
[0016]
Normally, as shown in FIG. 12, which explains the subjective evaluation of the shading unevenness, when the printing result exceeds ± 9% for the shading unevenness obtained by digitizing the printing result, and similarly when the emission energy unevenness exceeds ± 9%, the shading unevenness starts to be conspicuous. Fail in evaluation.
[0017]
The shading unevenness is determined by highlight density, characteristics of a developing process before fixing, transfer efficiency, assembly variation of each member, and the like.
[0018]
As an example, a description will be given of a variation in the assembly of the reflector 11 and the flash lamp 5. FIG. 13 shows shading when the reflection plate 11 is provided to be rotated with respect to the flash lamp 5, and FIG. 14 shows the case where the reflection plate 11 is provided to be shifted from the flash lamp 5 in the medium transport direction. Is shown.
[0019]
As shown in FIG. 13 (a), the reflector 11 is attached to the flash lamp 5 with the reference (I), + α ° rotation (II) from the reference, and −α ° rotation (III) from the reference, respectively. In this case, the emission energy distribution irradiated by one flash of the flash lamp 5 is as shown in FIG. Then, the energy distribution in the transport direction of the medium 3 when printing is performed while transporting the medium 3 is as shown in FIG.
[0020]
Further, as shown in FIG. 14A, the reflection plate 11 is displaced from the flash lamp 5 in the transport direction of the medium 3 by (I), by + γ mm from the reference (II), and by -γ mm from the reference. (III) When each is attached, the emission energy distribution irradiated by one flash of the flash lamp 5 is as shown in FIG. The energy distribution in the transport direction of the medium 3 when printing is performed while transporting the medium 3 is as shown in FIG.
[0021]
As shown in FIGS. 13 (d) and 14 (d), which are diagrams summarizing the maximum value, the minimum value, and the δ value of the energy distribution under each condition, the reflecting plate 5 is ± α °, ± When a mounting shift of γ mm occurs, each δ value is in the vicinity of ± 8.0 to ± 9.0%, which is close to the upper limit of light emission energy unevenness.
[0022]
However, the design margin of the above process has become extremely narrow with the increase in the resolution and the speed of the apparatus, and it has been demanded that the shading unevenness (light emission energy unevenness) be reduced.
[0023]
The present invention has been made in view of the above problems, and an object of the present invention is to provide a flash fixing device and a flash lamp free from shading.
[0024]
[Means for Solving the Problems]
FIG. 1 is a principle diagram of the invention described in claim 1 and the invention described in claim 5.
[0025]
In the figure, a toner image is formed by a toner 53 on a medium 51.
[0026]
A flash lamp 55 that emits light and fixes the toner image on the medium 51 by the radiant heat includes a cylindrical light emitting tube 57 and a trigger disposed on the outer peripheral surface of the light emitting tube 57 in substantially parallel with the axis O of the light emitting tube 57. And an electrode 59.
[0027]
In the present invention, the trigger electrode 59 includes two electrodes, a first trigger electrode 61 and a second trigger electrode 63.
[0028]
Then, on a cross section orthogonal to the axis O of the arc tube 57, with reference to the intersection of the straight line L passing through the axis O and parallel to the surface of the medium 51 on which the toner image is formed, and the outer peripheral surface of the arc tube 57. The first trigger electrode 61 is provided in the range A of the angular position 0 ° ± 30 °, and the second trigger electrode 63 is provided in the range B of the angular position 180 ° ± 30 °.
[0029]
When a pulsed high voltage is applied to the first trigger electrode 61 and the second trigger electrode 63, dielectric breakdown occurs along the first trigger electrode 61 and the second trigger electrode 63 in the arc tube 57, and Then, an arc discharge occurs to emit light.
[0030]
By causing dielectric breakdown at two locations in the arc tube 57 at the same time, the first light emitting region C and the second light emitting region D are generated by one flash lamp 55, which is almost equivalent to the effect of having two flash lamps. The energy difference between the portion where the flash light overlaps and the portion where the flash light does not overlap once is reduced, and the shading is eliminated.
[0031]
If the range of the angular positions 0 ° ± 30 ° and the angular positions 180 ° ± 30 ° is further expanded, the first light-emitting region C formed by the first trigger electrode 61 and the second light-emitting region D formed by the second trigger electrode 63. There is a case where the contact occurs, which is substantially the same as the light emitting region in the case of one trigger electrode, so that the unevenness of the light emission energy is not reduced and the unevenness of the light and shade is not eliminated.
[0032]
The invention according to claim 2 is the flash fixing device according to claim 1, wherein the trigger electrode is a conductive metal film formed on an outer peripheral surface of the arc tube.
[0033]
Since the trigger electrode is a conductive metal film formed on the outer peripheral surface of the arc tube, the flash lamp can be easily assembled.
[0034]
The invention according to claim 3 is the flash fixing device according to claim 1, wherein the trigger electrode is a conductive metal bar arranged along the outer peripheral surface of the arc tube.
[0035]
The cost can be reduced from the conductive metal film.
[0036]
The invention according to claim 4 is the flash fixing device according to claim 4, wherein an interval between the conductive metal rod and an outer peripheral surface of the arc tube is 0.5 mm or less.
[0037]
By setting the distance between the conductive metal rod and the outer peripheral surface of the arc tube to 0.5 mm or less, dielectric breakdown easily occurs in the arc tube, and both the first trigger electrode and the second trigger electrode emit light simultaneously. Can be easily done. If the distance between the conductive metal rod and the outer peripheral surface of the arc tube is larger than 0.5 mm, dielectric breakdown in the arc tube is less likely to occur, and both the first trigger electrode and the second trigger electrode emit light simultaneously. It becomes difficult.
[0038]
BEST MODE FOR CARRYING OUT THE INVENTION
Next, an embodiment of the present invention will be described with reference to the drawings.
[0039]
First, the overall configuration and operation of a printing apparatus provided with the flash fixing device of the present embodiment will be described with reference to FIG.
[0040]
As shown in the figure, the continuous paper (medium) 102 of the paper hopper 111 is continuously fed and stored in a stacker 112 via a transfer unit 107 and a flash fixing device 113. The photoreceptor drum 104 rotated clockwise is uniformly charged by the charger 103 and then exposed to an image by the optical system 105. As a result, an electrostatic latent image corresponding to the image is formed on the photosensitive drum 104. After the electrostatic latent image on the photosensitive drum 104 is developed by the developing device 106, the toner image on the photosensitive drum 104 is transferred to the continuous paper 102 by the transfer device 107. After the transfer, the photosensitive drum 104 is neutralized by the neutralizer 109, and the residual toner is cleaned by the cleaner blade 108 and the cleaner brush 110. The continuous paper 102 onto which the toner image has been transferred is flash-fixed by the flash fixing device 113 and then stored in the stacker 112.
[0041]
Next, the overall configuration of the flash fixing device 113 of FIG. 2 will be described with reference to FIG. The flash lamp 101 used was a cylinder of ozone-less quartz glass tube with an arc length of 502 mm and Xe (xenon) gas filled with 220 Toor.
[0042]
Further, the glass 122 provided between the flash lamp 101 and the continuous paper 102 is made of VAD hydrated synthetic quartz glass whose transmittance in the infrared light region is improved as compared with the conventional flame fused quartz glass. Using. Also, toner having an absorption wavelength in the infrared light region is used to improve the fixing property. As the reflection plate 123, an inner surface was subjected to aluminum reflection and then subjected to a reflection enhancement process.
[0043]
The invention according to claim 4 is the flash fixing device according to claim 4, wherein an interval between the conductive metal rod and an outer peripheral surface of the arc tube is 0.5 mm or less.
[0044]
When the distance between the conductive metal rod and the outer peripheral surface of the arc tube is larger than 0.5 mm, dielectric breakdown in the arc tube is less likely to occur, and both the first trigger electrode and the second trigger electrode can emit light simultaneously. It becomes difficult.
[0045]
Next, the flash lamp will be described with reference to FIG. 4 which is an axial sectional view of the flash lamp 101 shown in FIG. The flash lamp 101 has a cylindrical arc tube 157 and a trigger electrode 159 disposed on the outer peripheral surface of the arc tube 157 and substantially parallel to the axis O of the arc tube 157. The trigger electrode 159 of the flash lamp 101 according to the present embodiment includes two electrodes of a first trigger electrode 161 and a second trigger electrode 163 of a conductive metal bar. In the present embodiment, the first trigger electrode 161 and the second trigger electrode 163 are made of stainless steel, but may be made of an aluminum alloy, tungsten, or titanium. Further, a conductive metal film may be formed on the outer peripheral surface of the arc tube 157 to form the first trigger electrode 161 and the second trigger electrode 163. The conductive metal film includes, but is not limited to, indium tin oxide (ITO), zinc oxide, and tin oxide. The distance (t) between the first trigger electrode 161 and the second trigger electrode 163 and the outer peripheral surface of the arc tube 157 was set to 0.5 mm or less. If the interval (t) is wider than 0.5 mm, dielectric breakdown in the arc tube 157 is unlikely to occur, and it is difficult to emit light from both the first trigger electrode 161 and the second trigger electrode 163 simultaneously.
[0046]
At both ends of the arc tube 157, a main electrode (anode) 131 and a main electrode (cathode) 133 are provided. Reference numeral 135 denotes a lead wire for applying a pulsed high voltage to the first trigger electrode 161 and the second trigger electrode 163.
[0047]
Next, the arrangement of the first trigger electrode 161 and the second trigger electrode 163 will be described with reference to FIG. 5, which is a cross-sectional view of the flash fixing device 113.
[0048]
On a cross section orthogonal to the axis O of the arc tube 157, a reference is made to an intersection point between a straight line L ′ passing through the axis O and parallel to the surface of the continuous paper 102 on which the image of the toner 121 is formed and the outer peripheral surface of the arc tube 157. The first trigger electrode 161 was provided in the range A 'of the angular position 0 ° ± 30 °, and the second trigger electrode 163 was provided in the range B ′ of the angular position 180 ° ± 30 °.
[0049]
Next, the operation of the flash lamp 101 having the above configuration will be described. When a pulsed high voltage is applied to the first trigger electrode 161 and the second trigger electrode 163, dielectric breakdown occurs along the first trigger electrode 161 and the second trigger electrode 163 in the arc tube 157, and Then, an arc discharge occurs to emit light.
[0050]
By causing dielectric breakdown at two places in the arc tube 157 at the same time, two light-emitting regions, that is, a first light-emitting region C ′ and a second light-emitting region D ′ are generated simultaneously by one flash lamp 101.
[0051]
According to such a configuration, the following effects can be obtained.
[0052]
As shown in FIG. 6, it is assumed that light rays L1 and L2 are simultaneously emitted from the first light emitting area C ′ and the second light emitting area D ′ of the flash lamp 101 toward the point E of the reflector 123. Since the angles of incidence of the light rays L1 and L2 on the surface including the point E of the reflector 123 are different, the reflection angles are different. Thereafter, the light is reflected by the other surface of the reflection plate 123 and finally reaches different points, points F and G, of the continuous paper 102. Note that points F and G are portions where the flash light overlaps.
[0053]
Also, the light from the second light emitting area D ′ reaches the point F after being reflected by the reflector 123. Similarly, the light beam from the first light emitting area C 'reaches the point G.
[0054]
That is, the effect is almost the same as the effect of having two flash lamps, the energy difference between the portion where the flash light overlaps and the portion where the flash light is not applied once is reduced, and the shading is eliminated.
[0055]
When the range of the angular positions 0 ° ± 30 ° and the angular positions 180 ° ± 30 ° is further extended, the second light emission region C by the first trigger electrode 161 and the second light emission by the second trigger electrode 163 in FIG. There is a case where the region D comes into contact with the region D, which is substantially the same as the light emitting region in the case of a single trigger electrode.
[0056]
Further, as shown in FIG. 7, when three or more trigger electrodes are provided, there are the following problems.
(1) When the trigger electrodes 201 to 203 are conductive rod-shaped, it becomes difficult to manage the distance between the trigger electrodes 201 to 203 and the outer peripheral surface of the arc tube 157.
(2) When the number of trigger electrodes is increased, the area of a portion that does not emit light due to the trigger electrodes increases, and the luminous efficiency decreases.
[0057]
For these reasons, two trigger electrodes are preferable.
[0058]
(Supplementary Note 1) In a flash fixing device that emits a flash lamp and fixes a toner image formed on a medium by radiant heat,
The flash lamp has a cylindrical arc tube, and two trigger electrodes arranged on the outer peripheral surface of the arc tube substantially in parallel with the axis of the arc tube,
On a cross section orthogonal to the axis of the arc tube, passing through the axis, a straight line parallel to the surface of the medium on which the toner image is formed, and an intersection of the outer peripheral surface of the arc tube as a reference.
First trigger electrode in the range of angular position 0 ° ± 30 °,
The second trigger electrode in the range of 180 ° ± 30 ° angular position,
A flash fixing device characterized by being provided respectively.
[0059]
(Supplementary note 2) The flash fixing device according to supplementary note 1, wherein the trigger electrode is a conductive metal film formed on an outer peripheral surface of the arc tube.
[0060]
(Supplementary Note 3) The flash fixing device according to Supplementary Note 2, wherein the conductive film is any one of indium tin oxide, zinc oxide, and tin oxide.
[0061]
(Supplementary Note 4) The flash fixing device according to Supplementary Note 1, wherein the trigger electrode is a conductive metal rod arranged along an outer peripheral surface of the arc tube.
[0062]
(Supplementary note 5) The flash fixing device according to supplementary note 4, wherein the conductive metal rod is any one of stainless steel, an aluminum alloy, tungsten, and titanium.
[0063]
(Supplementary Note 6) The flash fixing device according to Supplementary Note 4 or 5, wherein a distance between the conductive metal rod and an outer peripheral surface of the arc tube is 0.5 mm or less.
[0064]
(Supplementary Note 7) In a flash lamp having a cylindrical arc tube and a trigger electrode disposed on an outer peripheral surface of the arc tube substantially in parallel with the axis of the arc tube,
On a cross section orthogonal to the axis of the arc tube, based on the intersection of a straight line passing through the axis and the outer peripheral surface of the arc tube,
A flash lamp in which a first trigger electrode is provided in an angular position range of 0 ° ± 30 ° and a second trigger electrode is provided in an angular position range of 180 ° ± 30 °.
[0065]
【Example】
In order to confirm the effects of the present embodiment, the inventor of the present application uses a flash lamp 101 configured as shown in FIG. Was measured. FIG. 8A shows that the reflection plate 123 is attached to the flash lamp 101 with the reference (I), the rotation + α ° from the reference (II), and the rotation −α ° from the reference (III). 4 shows the energy distribution in the transport direction of the continuous paper 102 when printing is performed while transporting the paper.
[0066]
As shown in FIG. 8B, which summarizes the maximum value, the minimum value, and the δ value of the energy distribution under each condition, the difference between the maximum value and the minimum value of the energy is reduced, and the δ value is also in the 6% range. It was confirmed to fit.
[0067]
【The invention's effect】
As described above, according to the first aspect of the present invention, since the first trigger electrode and the second trigger electrode are provided, light is emitted at two locations in the arc tube at the same time, which is almost the same effect as having two flash lamps. As a result, the difference in energy between the portion where the flash light overlaps and the portion where the flash light is not overlapped one time is reduced, and the shading unevenness is eliminated.
[0068]
In addition, on a cross section orthogonal to the axis of the arc tube, an angular position is determined based on an intersection of a straight line passing through the axis and parallel to a surface of the medium on which the toner image is formed, and an outer peripheral surface of the arc tube. By providing the first trigger electrode in the range of 0 ° ± 30 ° and the second trigger electrode in the range of the angular position of 180 ° ± 30 °, the light-emitting regions are overlapped to form one light-emitting region with sharp shading. Can be prevented.
[0069]
According to the second aspect of the present invention, since the trigger electrode is a conductive metal film formed on the outer peripheral surface of the arc tube, the flash lamp can be easily assembled.
[0070]
According to the third aspect of the present invention, the cost can be reduced more than the conductive metal film.
[0071]
According to the fourth aspect of the present invention, since the distance between the conductive metal rod and the outer peripheral surface of the arc tube is set to 0.5 mm or less, dielectric breakdown easily occurs in the arc tube, and the first trigger electrode And the second trigger electrode can easily emit light simultaneously. If the distance between the conductive metal rod and the outer peripheral surface of the arc tube is larger than 0.5 mm, dielectric breakdown in the arc tube is less likely to occur, and both the first trigger electrode and the second trigger electrode emit light simultaneously. It becomes difficult.
[Brief description of the drawings]
FIG. 1 is a principle diagram of the invention described in claims 1 and 5;
FIG. 2 is a configuration diagram of a printing apparatus provided with a flash fixing device according to an embodiment.
FIG. 3 is a perspective view of the flash fixing device of FIG. 2;
FIG. 4 is an axial sectional view of the flash lamp of FIG. 3;
FIG. 5 is a sectional view of the flash fixing device of FIG. 2;
FIG. 6 is a diagram illustrating effects of the embodiment.
FIG. 7 is a sectional view of a flash lamp having three trigger electrodes.
FIG. 8 is a diagram illustrating shading unevenness in a case where a reflecting plate is provided so as to rotate with respect to the flash lamp of the embodiment.
FIG. 9 is a configuration diagram of a flash fixing device.
FIG. 10 is a diagram showing a result obtained by printing a line of 1on1off in the sub-scanning direction at a resolution of 600 dpi by a printer using a flash fixing device having a configuration as shown in FIG. 9 and digitizing the result by a densitometer.
FIG. 11 is a diagram illustrating the distribution of light energy of a flash lamp using the reflector of FIG. 9;
FIG. 12 is a diagram for explaining the subjective evaluation of light emission energy and unevenness of printing density.
FIG. 13 is a view for explaining shading unevenness when the reflector is provided so as to rotate with respect to the flash lamp.
FIG. 14 is a view for explaining shading unevenness when a reflecting plate is provided shifted from the flash lamp in the medium transport direction.
[Explanation of symbols]
51 medium 53 toner 55 flash lamp 57 arc tube 61 first trigger electrode 63 second trigger electrode

Claims (5)

In a flash fixing device that emits a flash lamp and fixes a toner image formed on a medium by radiant heat,
The flash lamp has a cylindrical arc tube, and two trigger electrodes arranged on the outer peripheral surface of the arc tube substantially in parallel with the axis of the arc tube,
On a cross section orthogonal to the axis of the arc tube, passing through the axis, a straight line parallel to the surface of the medium on which the toner image is formed, and an intersection of the outer peripheral surface of the arc tube as a reference.
First trigger electrode in the range of angular position 0 ° ± 30 °,
The second trigger electrode in the range of 180 ° ± 30 ° angular position,
A flash fixing device characterized by being provided respectively. The flash fixing device according to claim 1, wherein the trigger electrode is a conductive metal film formed on an outer peripheral surface of the arc tube. 2. The flash fixing device according to claim 1, wherein the trigger electrode is a conductive metal rod disposed along an outer peripheral surface of the arc tube. The flash fixing device according to claim 4, wherein a distance between the conductive metal rod and an outer peripheral surface of the arc tube is 0.5 mm or less. In a flash lamp having a cylindrical arc tube and a trigger electrode disposed on an outer peripheral surface of the arc tube substantially parallel to an axis of the arc tube,
On a cross section orthogonal to the axis of the arc tube, based on the intersection of a straight line passing through the axis and the outer peripheral surface of the arc tube,
First trigger electrode in the range of angular position 0 ° ± 30 °,
The second trigger electrode in the range of the angular position of 180 ° ± 30 °,
Flash lamps, each of which is provided.

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