JP2872884B2 - Method and apparatus for preventing stain on glass window of fixing device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for preventing stains on a glass window of a fixing device of a flash lamp type used in an electrophotographic process.

[0002] In recent years, the printing of image images has increased and a high printing density has been demanded. In order to meet such demands, it is necessary to transfer a larger amount of toner onto the paper in the electrophotographic process than in the past, and it is desired to prevent the resulting toner from increasing the contamination of the glass window. Have been.

[0003]

2. Description of the Related Art FIG. 5 is a sectional view showing a schematic structure of a conventional fixing device 80. The fixing device 80 includes a flash lamp 81, a trigger wire 82, a reflection plate 83, a glass window 8
4, a casing 85, a suction device 86, and the like.

The trigger wire 82 is connected to the flash lamp 8
It is arranged on the opposite side of the sheet P so as to be along the longitudinal direction of the first tube wall and not to obstruct the light emitted by the flash lamp 81 from reaching the sheet P. A high voltage for starting discharge between the main electrodes of the flash lamp 81 is applied to the trigger wire 82. The polarity of the high voltage is usually a negative polarity so that a discharge or the like hardly occurs between the high voltage and the reflection plate 83.

[0005] The suction device 86 is for sucking air between the fixing device 80 and the paper P and discharging it upward to remove toner scattered from the paper P. When the flash lamp 81 emits light periodically, the glass window 8
The toner on the sheet P conveyed opposite to the sheet 4 is thermally fixed.

However, although the suction device 86 is used, since the sheet P and the glass window 84 are extremely close to each other, the scattered toner adheres to the glass window 84,
There is a problem in that it is fused to become dirty, and the transparency of the glass window 84 is reduced, thereby lowering the fixing efficiency. In particular, when the amount of toner transferred onto the sheet P as in an image image is large, and when a large amount of sheet P is printed, the tendency is remarkable.

As one measure for solving such a problem, two electrodes are embedded in the glass window 84 so that the surface of the glass window 84 facing the paper P is charged to the opposite polarity to the toner. It has been proposed to apply a DC voltage to the electrodes (JP-A-2-272593).

[0008]

However, the use of a special glass window in which electrodes are embedded as in the above-described conventional method for preventing contamination requires a special power supply device for applying a voltage to the electrodes. This is disadvantageous in terms of cost and maintenance.

In view of the above problems, the present invention does not require a special glass window in which electrodes are embedded or a special power supply device, and provides a method and apparatus capable of preventing toner from adhering to the glass window. The purpose is to do.

[0010]

According to a first aspect of the present invention, there is provided a method for solving the above-mentioned problems, as shown in FIG. 1 and FIG. Trigger wire 1 arranged along the direction and applied with a high voltage for starting discharge between main electrodes
2. A fixing device 3 having a reflector 13 for reflecting light emitted from the flash lamp 11 and a glass window 14 disposed between the flash lamp 11 and the paper P to which the toner TN is attached. In the first embodiment, the position of the trigger wire 12 along the circumferential direction of the tube wall is changed so that the surface 14b of the glass window 14 facing the paper P has the same polarity as the charged polarity of the toner TN. Is the way.

According to a second aspect of the present invention, the trigger wire is disposed on a side of the tube wall of the flash lamp close to the glass window in a circumferential direction, and the trigger wire is charged with the polarity of the toner TN. This is a method for preventing contamination by applying a high voltage having a polarity opposite to that of the above.

In the method according to a third aspect of the present invention, the position of the trigger wire 12 is set to be ± 20 from the position closest to the glass window 14 along the circumferential direction of the tube wall.
This is a dirt prevention method that is arranged at a position within the range of degrees.

In the prevention device 8 according to the fourth aspect of the present invention, the trigger wire 12 is disposed along the tube wall of the flash lamp 11 on the side near the glass window 14, and the trigger wire 12 includes the trigger wire 12. The configuration is such that a high voltage having a polarity opposite to the charging polarity of the toner TN is applied.

[0014]

For example, when a negative high voltage is applied to the trigger wire 12, if the position of the trigger wire 12 is set to the side of the reflection plate 13, the surface 14b of the glass window 14 facing the sheet P becomes negative, and the position of the trigger wire 12 is set. Assuming that the position is on the side of the glass window 14, the surface 1 of the glass window 14 facing the paper P
4b has a positive polarity. Therefore, in each case, when the polarity of the toner TN is negative or positive, they repel each other with the same polarity.

In particular, when the trigger wire 12 is arranged on the side close to the glass window 14, by applying a high voltage having a polarity opposite to the charging polarity of the toner TN to the trigger wire 12, the glass window 14 faces the sheet P. The polarity of the charged surface 14b is the same as the polarity of the toner TN, and the toner TN is repelled and does not adhere.

[0016]

FIG. 1 is a sectional view showing a schematic structure of a fixing device 3 according to the present invention, and FIG.
FIG. 3 is a perspective view of the flash lamp 11 showing an attached state of the trigger wire 12.

The fixing device 3 includes a flash lamp 11, a trigger wire 12, a reflector 13, a glass window 14, and the like. As shown in FIG. 3, the flash lamp 11 is a known type in which main electrodes are attached to both ends of a glass tube and a rare gas such as xenon gas is sealed inside. The flash lamp 11 is held at both ends by a bracket 21 fixed to a frame of a printer device (not shown) and a holding plate 22 attached to the bracket 21 by screws 23.

The trigger wire 12 is a wire made of tungsten or the like, and is arranged on the side near the glass window 14 in the circumferential direction of the tube wall of the flash lamp 11 and along the longitudinal direction of the tube wall of the flash lamp 11. Have been. A plurality of trigger rings 12a circumferentially surrounding the tube wall of the flash lamp 11 are connected to the trigger wire 12 at appropriate positions in the longitudinal direction. Trigger wire 12
Is connected to an electric wire 24, and the flash lamp 11
When a high voltage is periodically applied to the trigger wire 12 and the trigger ring 12a via the electric wire 24 in a state where a voltage is applied to the main electrode, the flash lamp 11 emits light periodically.

The reflector 13 is for efficiently reflecting the light emitted from the flash lamp 11 onto the paper P, and is fixedly attached to a frame (not shown). Therefore, the potential of the reflection plate 13 is zero. The distance between the closest point between the flash lamp 11 and the reflector 13 is about 8 mm.

The glass window 14 is provided to prevent and protect the flash lamp 11 from being stained. The glass window 14 is located at a distance of about 7 mm from the flash lamp 11 and about 8 mm from the sheet P passing through the conveyance path. Are arranged so as to face each other in parallel at a distance of. The glass window 14 is attached to the frame by a suitable support frame (not shown).

Although not shown, a power supply for applying a high voltage of about 1700 V to the main electrode of the flash lamp 11, a power supply for applying a high voltage of about 10 KV to the trigger wire 12, and a reflector 13 are covered. housing,
A suction device for suctioning and removing the toner TN is provided.

The trigger wire 12 has a toner TN
A high voltage having a polarity opposite to the charging polarity is applied. For example, as shown in FIG. 2, when the charge polarity of the toner TN is positive, a high negative voltage is applied to the trigger wire 12. Then, since the upper surface 14 a of the glass window 14 is close to the trigger wire 12, the glass window 14 is charged to the same negative polarity as the voltage applied to the trigger wire 12 through the ionized gas therebetween, and the lower surface 14 b is connected to the same. It is charged to the opposite positive polarity.

Therefore, the toner T adhering on the sheet P
N repels each other because the charged polarity and the polarity of the lower surface 14b of the glass window 14 are the same positive polarity, so that the adhesion to the glass window 14 is prevented.

When the charge polarity of the toner TN is negative, a high positive voltage is applied to the trigger wire 12.
Then, the lower surface 14b of the glass window 14 is charged to a negative polarity for the same reason as described above, and this and the toner TN repel each other, thereby preventing the toner TN from adhering to the glass window 14.

The application of a high voltage to the trigger wire 12 is performed, for example, at a period of 200 ms, whereby the flash lamp 11 emits light approximately five times per second. In the above-described embodiment, the trigger wire 12 is arranged so as to be located closest to the glass window 14 in the circumferential direction of the tube wall of the flash lamp 11. However, according to experiments by the present inventors,
It has been found that the same effect is obtained when they are arranged within a range of 20 degrees in the left and right circumferential directions from that position. FIG. 4 shows the experimental results.

FIG. 4 shows the degree of dirt on the glass window 14 when the trigger wire 12 in FIG. 1 is disposed at various angles up to 180 degrees, which is the opposite position. It is. According to FIG. 4, the degree of dirt is minimum until the angular position slightly exceeds 0 degrees to 20 degrees, the degree of dirt sharply increases when the angle position is larger than that, and reaches a maximum when the angle position is 40 degrees or more. Has become.

By arranging the trigger wire 12 within a range of 20 degrees from the position closest to the glass window 14 in the circumferential direction of the tube wall of the flash lamp 11, the adhesion of the toner TN to the glass window 14 is prevented. Can be prevented.

When the charge polarity of the toner TN is negative, the arrangement position of the trigger wire 12 is set to 180 degrees,
That is, by setting the position closest to the reflection plate 13, the adhesion of the toner TN to the glass window 14 can be prevented. That is, in this case, the upper surface 14a of the glass window 14
Is charged to a positive polarity opposite to the polarity of the trigger wire 12,
The lower surface 14b is charged to a negative polarity. Therefore, the polarity of the high voltage applied to the trigger wire 12 is set to, for example, negative, and the position of the trigger wire 12 is changed according to the charging polarity of the toner TN, so that the charging polarity of the lower surface 14b of the glass window 14 is the same as that of the toner TN. By setting the polarity, the adhesion of the toner TN to the glass window 14 can be prevented.

The position of the trigger wire 12 can be easily changed by loosening the screw 23 and rotating the flash lamp 11. Alternatively, with the flash lamp 11 fixed, the trigger ring 12a
May be rotated around the tube wall.

In the above-described embodiment, the structure, shape, material, dimensions, arrangement position, and the like of each part of the fixing device 3 and the prevention device 8 can be variously changed in accordance with the gist of the present invention.

[0031]

According to the present invention, it is possible to prevent toner from adhering to the glass window without requiring a special glass window in which electrodes are embedded or a special power supply device.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating a schematic configuration of a fixing device according to the present invention.

FIG. 2 is a diagram showing an example of a charged state of a glass window in the prevention device according to the present invention.

FIG. 3 is a perspective view of a flash lamp showing a mounting state of a trigger wire.

FIG. 4 is a graph showing an arrangement angle position of a trigger wire and a degree of contamination of a glass window.

FIG. 5 is a cross-sectional view illustrating a schematic configuration of a conventional fixing device.

[Explanation of symbols]

 Reference Signs List 3 Fixing device 8 Prevention device 11 Flash lamp 12 Trigger wire 13 Reflector 14 Glass window 14b Lower surface (surface) P paper TN toner

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Tomoaki Fukuda 35, Saho, Shato-cho, Kato-gun, Hyogo (No address) Inside Fujitsu Peripheral Machinery Co., Ltd. (56) References JP-A-2-272593 (JP, A) JP-A-57-138671 (JP, A) JP-A-61-13544 (JP, A) JP-A-60-78056 (JP, U) (58) Fields investigated (Int. Cl. ⁶ , DB name) G03G 13 / 20 G03G 15/20 H01J 61/54

Claims (4)

(57) [Claims] 1. A flash lamp (11), a trigger wire (12) arranged along a longitudinal direction of a tube wall of the flash lamp (11), to which a high voltage for starting discharge between main electrodes is applied. A reflector (13) for reflecting light emitted from the flash lamp (11), and a glass window (14) disposed between the flash lamp (11) and the paper (P) to which the toner (TN) is attached; ), The position of the trigger wire (12) along the circumferential direction of the tube wall is changed to change the position of the glass window (1).
4) A method for preventing a glass window of a fixing device from being stained, wherein the surface (14b) facing the paper (P) has the same polarity as the charging polarity of the toner (TN). 2. A flash lamp (11), a trigger wire (12) arranged along a longitudinal direction of a tube wall of the flash lamp (11), to which a high voltage for starting discharge between main electrodes is applied. A reflector (13) for reflecting light emitted from the flash lamp (11), and a glass window (14) disposed between the flash lamp (11) and the paper (P) to which the toner (TN) is attached; ), Wherein the trigger wire (12) is connected to the glass window (14) in a circumferential direction of a tube wall of the flash lamp (11).
Wherein a high voltage having a polarity opposite to the charging polarity of the toner (TN) is applied to the trigger wire (12). 3. The stain prevention method according to claim 2, wherein the position of the trigger wire (12) is set to ± 20 degrees from a position closest to the glass window (14) along a circumferential direction of the tube wall. A method for preventing contamination of a glass window of a fixing device, wherein the glass window is disposed at a position within a range. 4. A flash lamp (11), a trigger wire (12) arranged along a longitudinal direction of a tube wall of the flash lamp (11), to which a high voltage for starting discharge between main electrodes is applied, A reflector (13) for reflecting light emitted from the flash lamp (11), and a glass window (14) disposed between the flash lamp (11) and the paper (P) to which the toner (TN) is attached; In the fixing device (3) having the trigger wire (12), the trigger wire (12) is disposed along a tube wall of the flash lamp (11) on a side close to the glass window (14); (12) An apparatus for preventing contamination of a glass window of a fixing device, wherein a high voltage having a polarity opposite to a charging polarity of the toner (TN) is applied.