JPS6291970A - Electrophotographic recorder - Google Patents

Abstract

PURPOSE:To prevent a toner from being scattered again by interposing an insulating layer between a recording paper and a charging means. CONSTITUTION:An electric field is given from a charging means 6 to a recording paper 5 and a toner 4 through an insulating layer 7 on the outside peripheral surface of a transfer roll electrode 6A. The tone 4 is stuck uniformly on the surface of a photoconductive layer 1c; and when the toner 4 is supplied from a toner supply part 2, the toner is stuck as a thin uniform layer by a toner layer thickness control member 8. The recording paper 5 is charged positively through the insulating layer 7 by the transfer roll electrode 6A. When an optical beam 9 like a laser is irradiated on a photosensitive body from the rear, the electric resistance of the photoconductive layer 1c is reduced. Since a transparent electrode 1b is connected to a bias power source E, a minus electric charge having the polarity opposite to that of the charging electric charge of the recording paper 5 is charged to the toner 4 on the light-irradiated part through the photoconductive layer 1c. Thus, the attraction coulomb force acts between the negatively charged toner 4 and the positively charged recording paper 5 to transfer the toner 4 to the recording paper 5.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an electrophotographic recording device used in copying machines, facsimile machines, optical printers, and the like.

(Prior Art) The mainstream of conventional electrophotographic processes is the xerography method, which is basically divided into six steps. That is, the first step is to charge the photoreceptor, the second step is to expose the photoreceptor to light and form an electrostatic latent image, and the second step is to attach toner particles to the electrostatic latent image on the photoreceptor and develop it. Steps 1 to 3, a fourth step of transferring this developed image onto recording paper using an electric field, a fifth step of fixing the transferred image on the recording paper, and a cleaning step to remove toner particles remaining on the photoreceptor. It consists of 6 steps. In the conventional device, the first
Separate devices for performing the fourth step and the sixth step are separately arranged along a drum-shaped photoreceptor or sheet-like photoreceptor having a relatively large diameter, and the fifth step is The device for this purpose is placed in the conveyance path of the recording paper. 220-222). However, in this conventional process, a charging step and a cleaning step are both essential, resulting in a large number of steps.

Further, in the apparatus according to the above process, separate apparatuses for performing each step are arranged, which makes the apparatus large and difficult to reduce in thickness and size.

Therefore, in order to reduce the number of steps and shorten the printing time, the applicant of the present application proposed Japanese Patent Application No. 60-99369, Japanese Patent Application No. 60-103136 and Japanese Patent Application No. 60-1635.
No. 09 etc. have been filed.

The principle of these applications is that toner of a uniform thickness is adhered to the surface of a toner carrier long enough to reach the toner transfer section from the toner supply section, and the recording paper is placed opposite the toner at the toner transfer section. A charging means is provided on the back side of the recording paper. The toner is charged at the toner transfer portion to a polarity opposite to that of the charging means, and thereby the toner is attached to the recording paper by attraction Coulomb force.

(Problem to be Solved by the Invention) In a previous application of the present applicant, toner charged to the opposite polarity to the charging means adheres to recording paper by suction Coulomb force, but if the resistivity of the recording paper is low Then, once the toner adheres to the toner, a charge is injected from the charging means to make it have the same polarity as the recording paper, and the toner tends to scatter from the recording paper again. This causes problems such as a decrease in print density and spread of dots.

It is an object of the present invention to provide an electrophotographic recording device that prevents charge from being injected into the toner that has once adhered to recording paper, improves print quality, significantly reduces the number of steps, and has a simple configuration. It is about providing.

(Means for Solving the Problems) The present invention is characterized in that at least the toner supply section has a length sufficient to reach the toner transfer section, and toner of a uniform thickness is adhered to the surface of the toner supply section. A toner carrier, a recording paper that is conveyed opposite to the toner in a toner transfer section, a charging means provided on the back side of the recording paper, and a toner transfer section that charges the toner to a polarity opposite to that of the charging means. The apparatus includes means for adhering the toner to the recording paper by suction Coulomb force, and an insulating layer interposed between the recording paper and the charging means.

(Function) The toner on the toner carrier is charged to a polarity opposite to that of the charging means at the toner transfer portion, and is attached to the recording paper by suction Coulomb force. An insulating layer is interposed between the recording paper and the charging means, and this serves as a blocking layer to prevent charge from the charging means from being injected into the transferred toner, thereby preventing the toner from scattering again.

(Example) In FIG. 1, a toner carrier 1 has a length sufficient to reach from a toner supply section 2 to a toner transfer section 3, and toner 4 is adhered to the surface with a uniform thickness. There is. In this example, the toner carrier 1 is a photoreceptor, and its structure includes a transparent electrode 1b formed on the top surface of a transparent support 1a such as glass,
It consists of three layers with a photoconductive layer IC formed on the upper surface of this transparent electrode. In the toner transfer section 3, the recording paper 5 is conveyed with a gap between the surfaces of the photoconductive layer IC. On the back side of the recording paper 5, a transfer roller electrode 6A serving as a back electrode is provided as a charging means 6. An insulating layer 7 made of Teflon, Mylar, or the like is formed on the outer peripheral surface of the transfer roller electrode 6A, and an electric field is applied to the recording paper 5 and the toner 4 from the charging means 6 via the insulating layer 7. The toner 4 is uniformly adhered to the surface of the photoconductive layer IC, and when the toner 4 exits the toner supply section 2, it becomes a thin uniform layer and adheres to the surface by the toner layer thickness adjusting member 8. It is something. In this example, the recording paper 5 is positively charged by the transfer roller electrode 6A via the insulating layer 7. A weak attraction Coulomb force acts between the toner 4 and the positively charged recording paper 5, but it is not strong enough to be transferred to the recording paper 5, so at this stage the toner 4
is never transcribed. When the photoreceptor is irradiated with a light beam 9 such as a laser beam from the back side thereof, the electrical resistance of the photoconductive layer IC at the light irradiation portion is reduced. Since the transparent electrode 1b is connected to the bias power source E, the toner 4 on the light irradiation area passes through the photoconductive layer IC whose conductivity has increased due to light irradiation, and the toner 4 on the light irradiation part is charged with a polarity opposite to that of the recording paper 5. A negative charge is injected. Then, an attractive Coulomb force acts between the negatively charged toner 4 injected with charges of opposite polarity and the positively charged recording paper 6, and the toner 4 is transferred onto the recording paper 5. That is, the photoreceptor is exposed to light without being pre-charged, and the toner 4 in that area is directly transferred to the recording paper 5. Since the insulating layer 7 on the outer periphery of the transfer roller electrode 6A serves as a blocking layer, no positive charge is injected into the toner 4 adhering to the recording paper 5.
The toner is kept stably attached to the recording paper 5 and transported to the fixing section. Note that when applying a negative voltage to the charging means 6, the transparent electrode 1b may be positively biased, and the effect is the same, only that the polarity of the charge is reversed. Further, a laser oscillator is used as a light source for the light 9 that irradiates the photoreceptor.

LED arrays, liquid crystal shutters, etc. can be used.

According to another example shown in the second figure, a corona charger 6B is used as the charging means 6. An insulating layer 7B is supported by a support member 10 between the corona charger 6B and the recording paper 5, and the recording paper 5 is charged by the corona charger 6B via the insulating layer 7B. Other structures are similar to those shown in the first figure.

According to still another example shown in FIG. 3, the insulating layer 7C is
It is laminated and formed on the back surface of C. The recording paper 5C is charged from the transfer roller electrode 6C on the back side through the insulating layer 7C. Other structures are similar to those shown in the first figure.

According to still another example shown in FIG. 4, the toner carrier 1 is composed of an insulating support 11, and in the toner transfer section 3, a large number of recording electrodes are arranged at small intervals on the surface of the insulating support 11. 12 is the provision. The recording electrodes are provided insulated from each other at a pitch corresponding to the resolution or at intervals less than that, and are arranged in a line in a direction perpendicular to the conveyance direction of the recording paper 5C. The recording electrode 12 is an insulating support 1
Although they may be aligned on the same plane as the surface of 1, the illustrated one is aligned so as to protrude. Magnetic toner 14 having a uniform thickness is adhered to the surfaces of the insulating support 11 and the recording electrode 12. The toner 14 is conveyed by a magnetic field generating device 13 which is a toner conveying means. The recording electrode 12 is connected to the collector of an NPN transistor as a semiconductor switching element 15, and the drive signal generating means 16 is connected to the base of the transistor. During recording, a drive signal flows from the drive signal generation means 16 to the base of the semiconductor switching element 15, and as a result, when a collector current flows, charges of opposite polarity to the voltage applied by the charging means 6 are injected into the toner 14 on the recording electrode 12. be done. The toner 14 charged to the opposite polarity is attracted to the recording paper 5C by Coulomb force by the action of the charging means 6.

(Effects of the Invention) As described above, according to the electrophotographic recording device according to the present invention, the toner once attached to the recording paper is stably sent to the fixing section without scattering again, and the print density is improved. high,
Dots do not spread, improving printing quality.

[Brief explanation of drawings]

FIG. 1 is a sectional view of one embodiment of the device according to the present invention, and FIG.
The figure is a cross-sectional view of another embodiment, FIG. 3 is a cross-sectional view of still another embodiment, and FIG. 4 is a cross-sectional view of still another embodiment. 1... Toner carrier, 1a... Transparent support, 1b...
...Transparent electrode, 1c...Photoconductive layer, 2...Toner supply section, 3...Toner transfer section, 4.14...Toner, 5,5C...Recording paper, 6... Charging means, 6A, 6C... Transfer roller electrode, 6B... Corona charger, 7.7B, 7c... Insulating layer, 9... Light, 11... Insulating support, 12.
...Recording electrode, 15...Semiconductor switching element. that's all

Claims (1)

[Scope of Claims] 1. A toner carrier having a length sufficient to reach at least from the toner supply section to the toner transfer section and having a uniform thickness of toner adhered to its surface; A recording paper is conveyed opposite the toner at the toner transfer section, a charging means is provided on the back side of the recording paper, and the toner is charged at the toner transfer section to a polarity opposite to that of the charging means. An electrophotographic recording apparatus comprising: means for adhering to the recording paper by suction Coulomb force; and an insulating layer interposed between the recording paper and the charging means. 2. In claim 1, the toner carrier is a photoreceptor comprising a transparent electrode provided on the upper surface of a transparent support and a photoconductive layer provided on the upper surface of the transparent electrode, and the toner is suctioned onto recording paper using a coulomb. The force-adhesive means irradiates light onto the photoconductor from the back surface thereof, lowers the electrical resistance of the light irradiation section, and charges the toner on the light irradiation section to a polarity opposite to that of the charging means. An electrophotographic recording device characterized by: 3. In claim 1, the toner carrier is:
The toner transfer section has a plurality of recording electrodes arranged at small intervals and insulated from each other on the surface of an insulating support, and the means for adhering the toner to the recording paper by suction Coulomb force is to attach the toner to the recording electrodes. An electrophotographic recording apparatus characterized in that the toner on the recording electrode is charged to a polarity opposite to that of the charging means through a connected semiconductor switching element. 4. An electrophotographic recording apparatus according to claim 1, wherein the charging means is a back electrode, and the insulating layer is formed on at least the surface of the back electrode facing the recording paper. 5. An electrophotographic recording device according to claim 4, wherein the back electrode has a roller shape, and the insulating layer is attached to the outer peripheral surface of the roller. 6. An electrophotographic recording apparatus according to claim 1, wherein the charging means is a corona charger. 7. An electrophotographic recording device according to claim 1, characterized in that the insulating layer is laminated on the back side of the recording paper.