JP2861685B2 - Electrophotographic apparatus and electrophotographic method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic apparatus and an electrophotographic method.

[0002]

2. Description of the Related Art An electrostatic latent image formed on a photosensitive means such as a photosensitive drum is developed with toner, and the developed toner image is transferred onto paper and then fixed. In an electrophotographic apparatus used for electrophotography, in addition to plain paper, a thick paper having a paper thickness greater than that of ordinary paper, or a label having an adhesive applied to the back side can be continuously cut to a predetermined length by a perforation. There is a case where a toner image is fixed on tack paper or the like which is releasably attached on a base sheet.

In an electrophotographic apparatus, a light source including an LED array or the like for irradiating recording information onto the photosensitive drum, a developing section, a transfer charger, a cleaning section, a static elimination lamp, A charger and the like are arranged. For this reason, in the conventional electrophotographic apparatus, the paper conveyance path is necessarily curved, and if the above-mentioned thick paper or tacky paper is used, the thick paper is curved and has a bending habit. The sheet bends at the perforation to cause uneven conveyance, and the image on the paper is disturbed, and the toner image cannot be transferred well near the perforation. .

[0004] The present invention has been made in view of the above points, and an object of the present invention is to provide an electrophotographic apparatus and an electrophotographic method which can be used regardless of the type of paper and have excellent characteristics of the obtained image quality. And

[0005]

Means for Solving the Problems In order to achieve the above object, the present inventors have made intensive studies on the above-described electrophotographic apparatus. As a result, in a flash fixing type electrophotographic apparatus, when the fixing unit is used as the charge removing unit, the conveyance of the paper can be made substantially flat, and various papers such as thick paper and tack paper can be used. To achieve the present invention.

That is, in order to achieve the above object, according to the electrophotographic apparatus of the first invention of the present invention, a photosensitive medium, a latent image forming means for forming an electrostatic latent image on the photosensitive medium, Developing means for developing the electrostatic latent image on the photosensitive medium into a toner image to form a toner image; transfer means for transferring the toner image on the photosensitive medium onto paper; and fixing the toner image on the paper to the paper by flash light Fixing and discharging means for removing charge on the photosensitive medium after completion of transfer , and re-discharge means for removing charge on the photosensitive medium after removal of charge.
Flash light is applied during fixing and static elimination.
The foremost part of the photosensitive medium reaches the position of the charge removing means.
Includes means to control the amount of light in synchronization with reaching
The configuration is as follows.

Preferably, the fixing / discharging means includes a long flash lamp having a pair of arc electrodes, a trigger electrode provided at one end of the flash lamp,
A holding member for holding the trigger electrode at one end of the flash lamp; and a reflector provided on the back surface of the flash lamp so as to cover the flash lamp, and a trigger voltage applied to the trigger electrode. V (K
V), the distance m (mm) between the one arc electrode and the holding member, and the distance G (mm) between the end of the reflector corresponding to the other arc electrode are m ≧ G + 0. 3V, G
It is set so as to satisfy the relationship of ≧ 0.

According to the electrophotographic method of the second invention of the present invention, a latent image forming step of forming an electrostatic latent image on a photosensitive medium, and developing the electrostatic latent image on the photosensitive medium with toner its flat while fixing a developing step of forming a toner image, transferring the toner image on the photosensitive medium onto the sheet, the toner image on the sheet by the flash light to paper to
Static electricity removal of the photosensitive medium after transfer is completed by irradiation with shimmer light
And applying light to the photosensitive medium after static elimination.
Irradiating the photosensitive medium to remove electricity again.
Flash light was applied during the fixing and static elimination processes.
Synchronous with the foremost part of the photosensitive medium reaching the static elimination step
Then, the irradiation light quantity in the re-elimination step is controlled .

[0009]

The leakage light from the fixing / discharging means is applied to a photosensitive medium having a toner image transferred onto a sheet, and the photosensitive medium is discharged. At this time, although there are slight toner image residues on the photosensitive medium, the photosensitive medium is discharged together with these residues by light leaking from the fixing / discharge means. In the static elimination means, after the start of flash fixing by the fixing and static elimination means,
In synchronization with the arrival of the forefront of the photosensitive medium irradiated with the leakage light, the amount of static elimination light applied to the photosensitive medium from the re-elimination means is controlled in synchronization with the arrival of the light on the photosensitive medium before and after flash fixing. In this way, the amount of re-elimination light is optimized so that the potential difference does not change.

At this time, the fixing / static elimination means includes a long flash lamp provided with a pair of arc electrodes, a trigger electrode provided at one end of the flash lamp, and a trigger electrode connected to the flash lamp. A holding member for holding at one end, and a reflector provided on the back surface of the flash lamp so as to cover the flash lamp,
And a trigger voltage V (KV) applied to the trigger electrode.
And the distance m (mm) between the one arc electrode and the holding member and the distance G (mm) between the end of the reflector corresponding to the other arc electrode are m ≧ G + 0.3V, G If the setting is made so as to satisfy the relationship of ≧ 0, the flash lamp has a large amount of light, so that even if the leakage light is slight, the photosensitive medium is sufficiently discharged, and the leakage of the trigger voltage to the reflector is suppressed. The fixability of the toner image to the paper is improved.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of an electrophotographic apparatus and an electrophotographic method according to the present invention will be described below in detail with reference to FIGS. The electrophotographic apparatus 1 includes a light source 3 around a photosensitive drum 2, a developing unit 4 using powder toner, a transfer charger 5,
A cleaning unit 6 having a brush, a static elimination lamp 7 and a charger 8 are arranged, and these are known ones. In the development unit 4, a developer in which a carbon surface is coated with a resin is used. I have.

[0012] Then, an electrophotographic apparatus 1 relates the transport path R of the sheet substantially has a flat form shown by an arrow in the figure, guide plates P _G and the tractor T is disposed to the right of the photosensitive drum 2, the photosensitive drum On the left side of 2, a fixing unit 9 is disposed above the conveyance path R, and a plurality of conveyance belts 10 serving as sheet conveyance means are disposed below the conveyance path R. As shown in FIG. 2, the transport belt 10 includes two rotating shafts 11 and 12.
A blower housing 20 is provided in a space formed by a plurality of conveyor belts 10 with the endless belt wound between rollers 11a and 12a attached to the respective members. Are located in

The fixing device 9 develops the electrostatic latent image formed on the photosensitive drum 2 with powder toner in the developing unit 4,
Fixing / discharging means which also serves as a static eliminator for thermally fixing the toner image transferred onto the paper by the charger 5 and for neutralizing the photosensitive drum 2, and a flash lamp, for example, a xenon lamp 9b, is provided in a metal housing 9a. 9b is provided. Here, the inner surface of the housing 9a is a reflective surface so as to reflect the flash light at a high reflectance. Irradiated on the surface.

In this case, as shown in FIG. 3, the fixing device 9 moves the trigger electrode E _T along the outer wall of the xenon lamp 9b.
The provided the distance between the arc electrode E _A and the housing 9a of the xenon lamp 9b G (mm), the distance between the retaining band B which holds the arc electrode E _A and the trigger electrode E _T m (m
m), when the trigger voltage is V (KV), the following relationship is established between them. That is, m ≧ G + 0.3V, G ≧ 0 In normal flash fixing, in order to increase the efficiency of the flash lamp, as shown in FIG. 4, the xenon lamp 9b is brought as close as possible to the housing 9a having the function of a reflector. By reducing the vertical distance D (mm),
Paper from the arc electrode E _A shown in FIG. 3 by reference numeral y P
It is necessary to shorten the distance to the position where (length L) can be fixed.

However, the trigger voltage V is usually 10-20.
Since the voltage is about KV, if the xenon lamp 9b is too close to the housing 9a, the trigger voltage V leaks to the housing 9a. Therefore, in the conventional fixing device, the distance between the arc electrode E _A and the housing 9a G
-5 to-10 mm, the distance y from the arc electrode E _A to a position capable of fixing the sheet P is required about 30 mm, the distance D and the ratio of the trigger voltage V D / V (mm / KV ) is 0. It was necessary to be 3 or more.

[0016] Therefore, by setting as described above, the arc electrode E _A disposed in the housing 9a of the xenon lamp 9b can prevent leakage of the trigger voltage even closer to the housing 9a and, moreover, from the arc electrode E _A The distance y to a position where the sheet P can be fixed can be reduced. For example, when the distance G between the arc electrode E _A and the housing 9a and 5 mm, the distance y can be 17mm and about half.

In the blower housing 20, the toner image is transferred from the photosensitive drum 2 by the charger 5, and the sheet conveyed to the fixing unit 9 by the plurality of conveying belts 10 is sucked. It is to prevent. The blower housing 20 is disposed in a flat space formed by the plurality of transport belts 10 as shown in the drawing. Also, the blower housing 20
A plurality of suction holes 21 opening between the plurality of conveyor belts 10 are formed on the upper surface on the side of the sheet to be conveyed, and a blower 22 for sucking and discharging air in the housing 20 is provided below. Also, as shown in FIG.
A paper sensor 23 for detecting the presence or absence of a conveyed paper is provided at the upper part of the paper.

In the electrophotographic apparatus 1 constructed as described above, first, the photosensitive drum 2 rotating at a constant speed in the direction of the arrow is uniformly charged by the charger 8, and then the light beam having the recorded information is obtained. Is emitted from the light source 3. By this light beam irradiation, an electrostatic latent image corresponding to the recorded information is formed on the photosensitive drum 2, and this electrostatic latent image is developed by the developing unit 4 with powder toner by the rotation of the photosensitive drum 2, It becomes an image (visible image).

The toner image developed on the photosensitive drum 2 is transferred by a transfer charger 5 onto a sheet conveyed along a conveyance path R indicated by an arrow. The sheet on which the toner image has been transferred is sucked by the blower housing 20 and is conveyed to the fixing device 9 through the conveyance path R by the plurality of conveyance belts 10. In the fixing device 9, when the paper sensor 23 provided in the housing 20 detects the presence of the paper on which the toner image has been transferred, the xenon lamps 9b and 9b are turned on, and the unfixed toner image is melted by the generated heat, and the paper is melted. Settled on top.

At this time, in the electrophotographic method of the present invention, in flash fixing the toner image, the light leaking from the xenon lamps 9b, 9b is used to charge the photosensitive drum 2 after transferring the toner image onto the paper. Use it positively. That is, after the transfer of the toner image onto the sheet by the transfer charger 5, when the sheet is conveyed to the position of the fixing device 9, the xenon lamps 9 b start lighting. At this time, in synchronization with the arrival of the foremost portion of the photosensitive drum 2 irradiated with the leakage light of the xenon lamps 9b and 9b to the position of the charge removing lamp 7 as the charge removing means, the charge removing lamp 7 is rotated.
Turns off the amount of light irradiated on the photosensitive drum 2 or turns off the charge removing lamp 7. Accordingly, the light amount of the static elimination light of the photosensitive drum 2 is adjusted by the static elimination lamp 7, and the light intensity of the static elimination light is optimized so that the potential difference on the surface does not change before and after the flash fixing by the lighting of the xenon lamps 9b, 9b. Be transformed into As a result, the toner image on the sheet is properly transferred onto the sheet, and a sheet on which a uniform image is continuously fixed is obtained, and the image quality is further improved.

Needless to say, the residual toner image remaining on the photosensitive drum 2 without being transferred to the sheet is the first portion of the photosensitive drum 2 irradiated with the leakage light of the xenon lamps 9b, 9b. Before reaching the position, the cleaning unit 6 cleans and removes it. Further, since the xenon lamp 9b has a large amount of light, the photosensitive drum 2 is sufficiently discharged even if a residue of the toner image remains.

The photosensitive drum 2 which has been cleaned and neutralized in this manner is used for the next subsequent use. As is clear from the above description, the xenon lamp 9 of the fixing device 9
When b and 9b are used for neutralization of the photosensitive drum 2, the image quality of the paper on which the toner image is fixed is improved, and the paper transport path R can be formed substantially flat as shown in FIG. Therefore, according to the electrophotographic apparatus and the electrophotographic method of the present invention, the paper transport path R can be made substantially flat without curving, and the paper to be processed can be prevented from having an unnecessary curl.

As a result, there is an advantage that the paper does not have a curl particularly in the case of thick paper or tack paper. Moreover, in the case of tack paper, if the transport path R is curved,
There are problems such as the paper bending at the perforation, causing uneven conveyance, the toner image being unable to be transferred onto the paper near the perforation, and the tack being peeled off. So there is no such problem. For this reason, it is possible to continuously obtain an electrophotograph having more uniform image quality.

Here, when a bias voltage having a polarity opposite to the charging polarity of the toner image transferred onto the sheet by the charger 5 is applied to the blower housing 20, the cleaning life of the fixing device 9 is extended, and the toner image As a result, the image quality is further improved. That is, when the xenon lamps 9b, 9b are turned on when fixing the toner image by the fixing device 9, the unfixed toner image is melted by the generated heat and is fixed on the sheet. At the time of the flash fixing, the resin-coated carbon toner is thermally decomposed and scatters. However, since the bias voltage of the opposite polarity is applied to the blower housing 20, the scattered toner is electrostatically charged to the blower housing 20 side. Attracted. For this reason, the fixing device 9 does not cause the scattered toner to adhere to the reflection surface of the housing 9a or the xenon lamp 9b and become soiled, so that the generated flash light is appropriately irradiated onto the paper,
The fixability of the toner image is maintained for a long time.

Further, the transport belt for transporting the paper forms two types of conductive layers to which different voltages are applied on a base made of an electrically insulating material, and between the two types of conductive layers by the different voltages applied. The paper may be conveyed while being attracted by the lines of electric force acting. That is, as shown in FIGS. 5 to 7, each transport belt 10 is formed by forming a plurality of rows of first conductive layers 10 b and second conductive layers 10 c on the front and back surfaces of the insulating base 10 a in parallel to the transport direction. First conductive layer 10
b the voltages V ₁ to, the second conductive layer 10c of the voltage V _2,
Apply each. As a result, the lines of electric force act between the first conductive layer 10b and the second conductive layer 10c, and the sheet is attracted and conveyed by the lines of electric force. This makes it possible to reliably transport various types of paper without causing transport failure.

At this time, the polarity of the voltage applied to each of the insulating layers 10b and 10c is not limited as long as the potential difference between the insulating layers 10b and 10c is 1000 V or more, preferably 1400 V or more, but the apparent voltage is 0 V. Is more desirable. For example, a voltage V ₁ of 700 V is applied to the first insulating layer 10b.
And the second insulating layer 10c applies a voltage V ₂ of -700V, respectively. As means for applying, the first insulating layer 10
b denotes a contact or the like, and the second insulating layer 10c applies a voltage to the blower housing 20 disposed below, and applies a voltage by bringing the housing 20 into contact with the second insulating layer 10c.

Further, as shown in FIGS. 8 and 9, the transport belt has a first conductive layer 15b and a second conductive layer 15c alternately arranged on one surface of an insulating base 15a in parallel with the transport direction. Are formed in a plurality of rows, and each conductive layer 15b,
Even if different voltages V ₁ and V ₂ are applied to c, the sheet can be similarly attracted and conveyed by the generated lines of electric force.

[0028]

As is apparent from the above description, according to the electrophotographic apparatus and the electrophotographic method of the present invention, the paper transport path can be formed substantially flat, so that the toner is independent of the type of paper. An excellent effect of improving the image quality of an electrophotograph is obtained, for example, a sheet on which an image can be properly transferred and a sheet on which a uniform image is continuously fixed can be obtained.

Further, the fixing / static elimination means includes a long flash lamp having a pair of arc electrodes, a trigger electrode provided on one end side of the flash lamp, and a trigger electrode provided on one end of the flash lamp. A trigger member having a holding member for holding the end portion, a reflector provided on a back surface of the flash lamp so as to cover the flash lamp, and a trigger voltage V (KV) applied to the trigger electrode; Distance m (mm) between electrode and the holding member
And the distance G (mm) from the end of the reflector corresponding to the other arc electrode to satisfy the relationship of m ≧ G + 0.3V, G ≧ 0, the flash lamp has a large amount of light. Even if the leakage light is small, the photosensitive medium is sufficiently neutralized, the leakage of the trigger voltage to the reflection plate is suppressed, the fixability of the toner image on the paper is improved, and the image quality of the obtained electrophotograph is improved. It can be further improved.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating an electrophotographic apparatus and an electrophotographic method of the present invention, and is a schematic configuration diagram of an electrophotographic apparatus to which the electrophotographic method of the present invention is applied.

FIG. 2 is a plan view of a transport unit.

FIG. 3 is a detailed view showing an arrangement of a trigger electrode and the like in a fixing / static elimination unit.

FIG. 4 is a side view showing a vertical arrangement of a housing and a xenon lamp which constitute a fixing / discharging unit.

FIG. 5 is a plan view showing another embodiment of the conveyor belt, together with a blower housing.

FIG. 6 is a plan view partially showing the transport belt of FIG. 5;

FIG. 7 is a cross-sectional view of the conveyance belt of FIG. 5 cut along a conveyance direction.

FIG. 8 is a plan view partially showing still another mode of the transport belt.

9 is a cross-sectional view of the conveyance belt of FIG. 8 cut along a conveyance direction.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Electrophotographic apparatus 2 Photosensitive drum 3 Light source 4 Developing part 5 Charger (for transfer) 6 Cleaning part 7 Static elimination lamp (Recharge elimination means) 8 Charger 9 Fixer (Fixing / static elimination means) 9a Housing 9b Xenon lamp 10,15 conveyor belts 10a, 15a insulation base 10b, 15b first conductive layer 10c, 15c second conductive layers 11 and 12 rotating shaft 11a, 12a roller 20 blower housing 21 suction hole 22 blower 23 paper sensor B holding band E _A arc electrode E _T Trigger electrode P Paper R Transport path

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) G03G 13/20 G03G 15/20 G03G 21/08

Claims (3)

(57) [Claims] A photosensitive medium; a latent image forming means for forming an electrostatic latent image on the photosensitive medium; a developing means for developing the electrostatic latent image on the photosensitive medium with a toner to form a toner image; Transfer means for transferring the toner image on the photosensitive medium onto the sheet, fixing means for fixing the toner image on the sheet to the sheet by flash light and static elimination of the photosensitive medium after transfer is completed, A static eliminator for performing a static elimination of the photosensitive medium, and the static eliminator is configured to perform a static elimination during fixing
The foremost part of the photosensitive medium irradiated with flash light is
The irradiation light amount is synchronized with reaching the position of the
An electrophotographic apparatus comprising means for controlling . 2. The fixing / eliminating means includes: a long flash lamp having a pair of arc electrodes; a trigger electrode provided at one end of the flash lamp; and a trigger electrode provided on one end of the flash lamp. And a reflector provided on the back surface of the flash lamp so as to cover the flash lamp, and a trigger voltage V (KV) applied to the trigger electrode; Distance m (mm) between arc electrode and the holding member
2. The electrophotographic apparatus according to claim 1, wherein a distance G (mm) between the second arc electrode and an end of the reflection plate corresponding to the other arc electrode satisfies the following relationship. m ≧ G + 0.3V, G ≧ 0 3. A latent image forming step of forming an electrostatic latent image on a photosensitive medium, a developing step of developing the electrostatic latent image on the photosensitive medium with a toner to form a toner image, and a toner on the photosensitive medium. A transfer step of transferring an image onto a sheet, a fixing / discharge step of fixing a toner image on the sheet to the sheet by flash light, and discharging the photosensitive medium after transfer by irradiation of the flash light; Irradiating the photosensitive medium with light to remove static electricity from the photosensitive medium again, and the foremost part of the photosensitive medium irradiated with the flash light in the fixing / static elimination step is a charge elimination step. And controlling the amount of irradiation in the re-elimination step in synchronism with the arrival of the image.