JP2845074B2 - Image recording device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a printer, a copying machine,
With respect to an image recording apparatus such as a facsimile, in particular, an electrostatic latent image is formed on an electrostatic latent image carrier according to image information, the electrostatic latent image is developed, and the developed image is formed on a transfer medium by pressure. The present invention relates to an image recording apparatus that performs simultaneous transfer and fixing.

[0002]

2. Description of the Related Art Conventionally, as this type of image recording apparatus,
For example, there is one disclosed in Japanese Patent Publication No. 57-501348. As shown in FIG. 5, the image recording apparatus forms an electrostatic latent image on the surface of a dielectric drum 100 by a recording head 101 in accordance with image information, and forms the electrostatic latent image formed on the dielectric drum 100. The image is developed by the developing device 102. Then, a pressure roller 103 is brought into pressure contact with the dielectric drum 100, and the recording paper 104 is passed through a nip portion between the dielectric drum 100 and the pressure roller 103, thereby forming the recording medium 104 on the dielectric drum 100. The developed image is configured to be transferred and fixed onto the recording paper 104 simultaneously with pressure to record an image.

In this image recording apparatus, the transfer step and the fixing step are performed at the same time, so that the parts can be simplified and the reliability can be improved. In addition, since the heating means is not required, the power consumption is reduced. It has the advantage of.

[0004]

However, the above-mentioned prior art has the following problems. That is, in the image recording apparatus as described above, the developed image formed on the dielectric drum 100 is simultaneously transferred and fixed onto the recording paper 104 by pressure to record an image. It is necessary to apply a large load of 200 to 800 kg between the drum 100 and the pressure roller 103. Therefore, the movement of the recording paper 104 is strongly restricted at the pressure contact portion between the dielectric drum 100 and the pressure roller 103. The moisture content of the recording paper 104 on which an image is recorded changes due to changes in the environment such as temperature and humidity. However, when the recording paper 104 is stored in the apparatus for a long period of time, it changes in the paper due to changes in the external environment. The water content is not uniform, and the recording paper 104 is deformed such as wavy. When the recording paper 104 thus deformed is conveyed to the pressure contact portion, the movement of the recording paper 104 is strongly restricted, and deformation such as waving generated on the recording paper 104 is converged to form wrinkles. There is a problem in that the concentration of pressure on the portion causes the surface of the dielectric drum 100 and the pressure roller 103 to be scratched.

In order to solve this problem, Japanese Utility Model Application Laid-Open No.
As disclosed in Japanese Patent Application Laid-Open No. 2-74262 as a technology relating to a pressure fixing device, a sheet-like transfer material carrying a toner image is passed through a pressure nip portion of a pair of rollers that press against each other to transfer the toner image. In a pressure fixing device for fixing and fixing to a material, measures such as forming one of the pair of rollers into an inverted crown shape are taken, and the pressure is fixed to a sheet-like transfer material which is pressure-fixed by a pressure contact nip portion of the pair of rollers. It is also conceivable to prevent wrinkles from occurring by applying an outward tension along the axial direction of the roller.

However, when this method is adopted, the following new problems arise. That is, in the above-mentioned pressure fixing device, the above-mentioned JP-A-57-50 is used.
As disclosed in Japanese Patent Publication No. 1348, in order to equalize the fixing pressure along the axial direction of the rollers, the axes of the rollers are crossed at an angle, but one of the pressure rollers is formed in an inverted crown shape. In such a case, since the pressure at the roller end portions is further increased, it is necessary to set the intersection angle between the rollers to be further larger. However, in an image recording apparatus using pressure transfer fixing, the dielectric drum 100 and the pressure roller 1
03, the image formed on the dielectric drum 100 and the dielectric drum 100 and the pressure roller 1 are increased.
The conveyance direction of the recording paper 104 passing through the nip portion between 03 and the image formed on the dielectric drum 100 is largely shifted, and the image is distorted and transferred from the dielectric drum 100 to the recording paper 104. As a result, there is a new problem that image quality is deteriorated.

SUMMARY OF THE INVENTION Accordingly, the present invention has been made to solve the above-mentioned problems of the prior art, and an object of the present invention is to provide an image recording apparatus employing a pressure transfer fixing system, wherein recording paper is formed without deteriorating image quality. An object of the present invention is to provide an image recording apparatus capable of preventing generation of wrinkles.

[0008]

Means for Solving the Problems The technical problems described above are:
The toner image formed on the surface of the image carrier is transferred and fixed by pressure on a transfer medium supplied to a pressure contact portion between the pressure roller and the image carrier, which presses the surface of the image carrier. In the image recording apparatus that performs the recording of the transfer medium, the conveying unit that conveys the transfer medium to a pressure contact portion between the image carrier and the pressure roller conveys the transfer medium faster at both ends than at the center along the width direction of the transfer medium. This is achieved by configuring

As the above-mentioned conveying means, for example, one having at least one roller having an inverted crown-shaped roller having a diameter at both ends larger by a predetermined amount than a diameter at the center is used.

[0010]

According to the present invention, the transport means for transporting the transfer medium to the pressure contact portion between the image carrier and the pressure roller is configured to transport the transfer medium at both ends faster than at the center along the width direction of the transfer medium. Therefore, even when the transfer medium absorbs moisture unevenly and deforms such as waving, the transfer medium is conveyed faster by transporting both ends than the center along the width direction of the transfer medium. Both ends of the medium can be sandwiched between the press-contact portions of the image carrier and the pressure roller faster than the center portion along the width direction of the medium, and a force to pull the transfer medium outward in the width direction can be applied, and wrinkles occur on the transfer medium. Can be prevented.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below based on the illustrated embodiment.

FIG. 2 shows an embodiment of the image recording apparatus according to the present invention.

In FIG. 1, reference numeral 1 denotes a dielectric drum as an electrostatic latent image carrier. As the dielectric drum 1, for example, a surface of a conductive substrate 1a made of an aluminum drum or the like is used as an anode. The dielectric layer 1b formed by oxidizing the aluminum oxide on the surface and sealing the surface with an epoxy resin is used. An electrostatic latent image is formed on the surface of the dielectric drum 1 by a recording head 2 as an electrostatic latent image writing head in accordance with image information.

As the recording head 2, for example, the one disclosed in Japanese Patent Application Laid-Open No. 59-164154 is used. As shown in FIG. 3, the recording head 2 defines a transfer fluid supply device 3 and a passage 4 through which the transfer fluid is poured onto the surface of the dielectric drum 1, and includes an ion generator 5 and an ion modulator 6. The ion generator 5 is disposed adjacent to the passage 4, starts RF arc discharge in the passage 4, and directly generates positive and negative ions in the transfer fluid moving in the passage 4. Wherein the ion modulator 6 is disposed adjacent to the passage 4 and a plurality of spaced conductive modulation electrodes 7 on one side of the passage 4, and a conductive member on the opposite side of the passage from the modulation electrode. 8, a modulation potential source 9, a switch device 10 for selectively connecting the modulation potential source 9 to each of the modulation electrodes 7, and a reference potential source 11 connected to the conductive member 8. When the device 10 is excited, each of the modulation electrodes 7 Those that are configured to control the passage of the ion beam from the passage 4. The recording head 2 is described in, for example,
In addition to those disclosed in JP-A-164154, those disclosed in JP-A-61-51355 and the like may be used.

As shown in FIG. 2, the electrostatic latent image formed on the dielectric drum 1 is developed by a developing unit 12 to be visualized. As the developing device 12, a developing device which forms a toner for pressure fixing in a thin layer on the developing roller 12a to develop an electrostatic latent image is used.

The developed image formed on the dielectric drum 1 by the developing device 12 is simultaneously transferred onto a recording paper 14 as a transfer medium by a pressure roller 13 which is pressed against the dielectric drum 1 at a predetermined pressure. Be established.

After that, the surface of the dielectric drum 1 is cleaned of residual toner and the like by a metal blade 15a in a cleaner 15 and then charged by a charger 1 composed of a scorotron or the like.
The surface potential is made uniform by 6 to prepare for the next image recording step.

In this embodiment, the transport means for transporting the transfer medium to the press-contact portion between the image carrier and the pressure roller transports the transfer medium at both ends faster than at the center along the width direction of the transfer medium. Is configured.

That is, the recording paper 14 is accommodated in a recording paper tray 20.
Then, the recording paper 14 is separated and supplied one by one by a feed roller 21, and is abutted against a registration roller 22. Since the registration roller 22 is disposed in parallel to the dielectric drum 1, the leading end of the recording paper 14 is set at a fixed angle (for example, a direction orthogonal to the axial direction of the dielectric drum 1). The registration roller 22 is intermittently driven to rotate so that the recording paper 14 can be sent out toward the pressure contact portion at a predetermined timing in accordance with the writing of the latent image. Has become. The recording paper 14 sent out by the registration roller 22 is a final stage roller pair 2
Reaches 3,24.

The final roller pair 23, 24 is formed in a shape as shown in FIG. That is, the upper roller 23 is made of a metal such as aluminum or stainless steel, and has an inverted crown-shaped taper such that the outer diameter thereof gradually increases at both ends as compared with the center. The outer diameter difference between the center and both ends of the upper roller 23 is set to about 0.1% to 0.5% with respect to the diameter. on the other hand,
The lower roller 24 is configured by covering a surface of a metal roller 24a having a diameter of about 10 mm with a rubber 24b having a thickness of about 1 to 2 mm. And this final stage roller pair 2
By means of 3 and 24, the recording paper 14 is fed out at a rate determined by the taper amount at both ends with respect to the center in the width direction. Since the position of the last stage roller pair 23, 24 is disposed at a distance shorter than the length of the recording paper 14 with respect to the pressure contact portion, the recording paper 14 reaches the pressure contact portion more than the central portion. Both ends are faster. Incidentally, the traveling speed of the recording paper at the dielectric drum 1, the last roller pair 23, 24, and the registration roller 22 is V (dielectric drum) <V (last roller pair) <V (registration roller). I have.

With the above arrangement, in the image recording apparatus according to this embodiment, wrinkling of the recording paper is prevented as follows. That is, in this image recording apparatus, as shown in FIG. 2, an electrostatic latent image is formed on the surface of the dielectric drum 1 by the recording head 2 in accordance with image information, and the electrostatic latent image formed on the dielectric drum 1 is formed. The electrostatic latent image is developed by the developing unit 12 using a toner for pressure fixing, and is visualized.

Next, the toner image formed on the surface of the dielectric drum 1 is simultaneously transferred and fixed on a recording paper 14 by pressure by a pressure roller 13 pressed against the surface of the dielectric drum 1.

At this time, the recording paper 14 is stored in a recording paper tray 20, and the recording paper 14 is separated from the recording paper tray 20 by a feed roller 21 and supplied one by one. However, this recording paper 14
The amount of water changes due to changes in the environment such as temperature and humidity. However, when stored in the apparatus for a long period of time, the amount of water becomes non-uniform in the paper due to changes in the external environment. Deformation may occur.

The recording paper 14 supplied one by one by the feed roller 21 is abutted against a registration roller 22 and temporarily stopped, and the registration roller 22 temporarily stops the electrostatic latent image on the dielectric drum 1. The final stage roller pair 23, 24 at a predetermined timing according to writing.
Sent out to.

As shown in FIG. 1, the final roller pair 23, 24 has an inverted crown-shaped taper such that the outer diameter of the upper roller 23 is gradually larger at both ends than at the center. Therefore, the final roller pair 23, 2
4, the recording paper 14 is fed out at a rate determined by the taper amount at both ends with respect to the center in the width direction. Therefore, the reason why the recording paper 14 reaches the press contact portion is as follows.
As shown in FIG. 4, both ends are faster than the center.

As described above, since the recording paper 14 reaches the press-contact portions at both ends faster than the central portion thereof, even if the recording paper 14 contains water unevenly and causes waving, the image is transferred without causing paper wrinkling. Can be fixed simultaneously.

In the above embodiment, when the A4 recording paper 14 is fed from the short side, both ends are 0.5 m from the center.
The taper amount of the upper roller 23 is determined so as to reach the press-contact portion m faster.

According to the experimental results of the present inventor, if this difference is too large, wrinkles will be generated at the front end of the recording paper 14, whereas in the past, wrinkles were generated at the rear end of the recording paper 14. Therefore, in order to suppress the occurrence of wrinkles on the recording paper 14, although there is a difference depending on the size of the recording paper 14,
It is necessary to set the difference in reaching the press contact portion between about 0.1 to 1 mm.

In the above-described embodiment, an example is shown in which one of the metal rollers of the last pair of rollers 23 and 24 is provided with an inverted crown-shaped taper as a means for causing both end portions of the recording paper to reach the press contact portion first. The roller coated with rubber may have an inverted crown-shaped taper, or both rollers may have an inverted crown-shaped taper. Needless to say, it is not limited to the final stage roller pair.
The same effect can be obtained by forming the pair of registration rollers as described in the above embodiment. Finally, as a method of quickly reaching both ends of the recording paper to the pressure contact portion, a plurality of rollers divided in the width direction are arranged side by side,
A system in which the same effect is obtained by changing each feed speed is also conceivable.

Although the present invention has been described with reference to an image recording apparatus using a dielectric drum and an electrostatic latent image writing head as an example, the image recording apparatus forms an electrostatic latent image on an image carrier. Needless to say, it is only necessary to develop it and transfer and fix it on the recording paper on the image carrier at the same time. Of course, a laser beam, an LED, a fluorescent display tube, an optical recording head such as an EL, etc. An image recording apparatus that forms an electrostatic latent image by performing exposure may be used.

[0031]

According to the present invention, there is provided an image recording apparatus using the pressure transfer fixing method which can prevent wrinkles from occurring on recording paper without deteriorating image quality. Can be provided.

[Brief description of the drawings]

FIG. 1 is a partially cutaway configuration diagram showing a main part of an embodiment of an image recording apparatus according to the present invention.

FIG. 2 is a configuration diagram showing an embodiment of an image recording apparatus according to the present invention.

FIG. 3 is a configuration diagram showing a recording head.

FIG. 4 is an explanatory plan view showing a recording paper conveyance state.

FIG. 5 is a configuration diagram showing a conventional image recording apparatus.

[Explanation of symbols]

Reference Signs List 1 dielectric drum, 2 recording head, 12 developing device, 1
3 pressure roller, 14 recording paper, 23, 24 final stage roller pair.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) G03G 13/16 G03G 13/20 G03G 15/16 G03G 15/20

Claims (2)

(57) [Claims] 1. A method for simultaneously transferring a toner image formed on the surface of an image carrier onto a transfer medium supplied to a pressure contact portion between the pressure roller and the image carrier, which is pressed against the surface of the image carrier. In an image recording apparatus that records an image by fixing, a conveying unit that conveys the transfer medium to a pressure contact portion between the image carrier and a pressure roller has both ends rather than a central portion along a width direction of the transfer medium. An image recording apparatus configured to convey paper quickly. 2. The image according to claim 1, wherein said conveying means has an inverted crown-shaped roller in which at least one roller has a diameter at both ends larger by a predetermined amount than a diameter at a center. Recording device.