JPH0512704B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field: The present invention relates to a recording method using a photoconductive toner, and more particularly, to a recording method using a photoconductive powder toner charged by abrasion to produce positive and negative optical images. The present invention relates to a recording method that can form any image satisfactorily.

Prior art: In a recording method using photoconductive toner,
It is important to uniformly and reliably form a toner layer on the image forming surface in order to obtain a good visible image. Conventional recording methods include, as shown in Figure 1.
A bias potential is applied to the conductive substrate 100, and the previously charged toner 101 is rubbed onto the conductive substrate 100.
Magnet roll 1 which is a counter electrode of base 100
02 is known (see Japanese Unexamined Patent Publication No. 53-68233). In the method disclosed in this publication, a bias potential is applied to the substrate 100 when toner 101 is transferred to the substrate 100. However, when the charged toner 101 on the base 100 is exposed to a light image, the switch is switched and the base 100 is grounded. Therefore, in such a method, the electric charge of the photoimage-exposed portion of the charged toner 101 on the substrate 100 is dissipated through the substrate 100. Then, the charged toner portion that is not exposed to the light image is
The image is transferred to a recording sheet by a transfer charger, and a positive optical image is obtained.

In such a recording method, the charged toner that has been exposed to a photoimage loses its charge, so that toner portion cannot be transferred to the recording sheet. Therefore, with such a recording method, only a positive optical image can be formed, and it is impossible to form a negative image.

In addition, a magnet 104 is attached to the back side as shown in FIG.
A recording method is known in which a photoconductive magnetic toner 106 is magnetically attracted to the surface of a conductive substrate 105 having a conductive substrate 105 to form a uniform and single toner layer on the surface of the substrate (Japanese Patent Application Laid-Open No. 1986-1999). (See Publication No. 125767). In the method disclosed in this publication as well, as in the above publication, since the conductive substrate 105 is exposed to light while being grounded, the charged toner that has been exposed to light loses its charge and a positive light image is formed. I can only get images.

Object of the invention: An object of the invention is to provide a recording method that can selectively obtain either a positive image or a negative image of an optical image. Another object of the present invention is to provide a recording method in which a thin toner layer is uniformly and reliably formed on a substrate.

Summary of the Invention: The recording method of the present invention includes (1) a step of polishing and charging a photoconductive powder toner to a predetermined polarity, and (2) a grounded conductive blade as a counter electrode near the surface. (3) adsorbing the charged toner onto the substrate and uniformly covering the surface of the substrate with a toner layer; (4) exposing the toner layer with a light image while applying a bias potential to the substrate; (5) exposing the toner layer to a light image with a bias potential applied to the substrate; a step of injecting a bias charge to form an electrostatic latent image; and (6) a step of transferring toner having a charge of one polarity among the toners on the surface of the substrate to a transfer sheet, This achieves the above objective.

Examples: The present invention will be described in detail below based on examples and with reference to the drawings.

According to the recording method of the present invention, first, as shown in FIG. 3, the photoconductive powder toner 10 contained in the hopper 1 is charged by abrasion by the stirring member and the hopper wall surface. It has a + polar charge. On the other hand, as shown in FIG. 4, a bias potential is applied to the conductive substrate 2, and the conductive substrate 2 is charged to a negative polarity opposite to that of the charged toner 11. A conductive blade 3 is arranged near the surface of the base body 2, for example at the hopper 1, with a predetermined gap therebetween as a counter electrode. This conductive blade 3 is grounded. An electric field is generated between the base 2 and the blade 3 such that the charged toner 11 is directed toward the base 2. When the charged toner 11 is supplied to the surface of the base 2 from above, the charged toner 11 adheres uniformly and reliably to the surface of the base. The strength of the electric field rapidly decreases due to the shielding effect in the area where the toner 11 adheres and a toner layer is formed, but by relatively moving the base 2, a toner layer continues to be formed on the base 2. .

Next, as shown in FIG. 5, the toner layer on the substrate 2 is formed into an optical image by the optical system 4 while a negative bias potential having a polarity opposite to that of the toner layer is applied to the substrate 2. exposed to light. The exposed toner 12 acquires conductivity, its positive charge is neutralized by the bias charge injected from the substrate 2, and further receives the injection of a negative charge from the substrate 2. As a result, the toner 12 exposed to the optical image is charged from the initial positive polarity to the opposite polarity, negative polarity. In this way, a static latent image is formed on the substrate 2 by toners of different polarities.

Next, as shown in FIG.
Corona discharge is performed to charge the sheet 5 to a polarity opposite to that of the +-charged toner 11 which has not been exposed to a photoimage. As a result, the + polarity toner 11 that has not been exposed to a photoimage and retains its original charge is transferred onto the sheet 5. As a result, a toner image, which is a positive optical image, is obtained on the sheet 5. When the sheet 5 is charged by the charger 6 to the same polarity as the + charged toner 11 which has not been exposed to a photoimage and retains its original charge, the sheet 5 is charged with the same polarity as the charged toner 11 which has not been exposed to a photoimage and has been exposed to a photoimage on the substrate 2. Polarity reversed-charged toner is transferred. Therefore, a negative optical image is obtained on the sheet 5.

FIG. 7 shows an example of a recording apparatus suitable for continuously carrying out the above steps of the present invention. Hopper 1
is made of tetrafluoroethylene resin (trade name: Teflon) or is coated with tetrafluoroethylene resin on a suitable electrically insulating material. The toner 10 accommodated here is charged by polishing. The charging polarity of the toner 10 is determined depending on the polishing charging series between the toner and the hopper. When the hopper is made of tetrafluoroethylene resin, the toner is generally +
charged to the pole. A bias potential is applied to the conductive base drum 2, and the conductive base drum 2 is charged to have a polarity opposite to that of the toner 11 charged by polishing. The base body 2 is made of, for example, an inexpensive and easily moldable metal such as aluminum.
The conductive blade 3 is provided on the hopper 1 with a predetermined gap from the surface of the base 2. This blade 3
is grounded and also functions as a counter electrode for the base 2. An electric field is generated in the vicinity of the base 2 and the blade 3 so that the charged toner 11 is directed toward the base 2. Therefore, the charged toner 11 is attracted to the surface of the base 2 and strongly adheres thereto. Since the base body 2 is rotating in the direction of the arrow, a toner layer is sequentially and uniformly formed on the surface of the toner layer, and the toner layer is conveyed to the base body 2. The toner layer is then exposed to a light image by the imaging optical system 4 while a negative bias potential having a polarity opposite to that of the toner layer is applied to the substrate 2 . Then, the toner 11 constituting the toner layer
The exposed toner 12 acquires conductivity and the held positive charge is neutralized by the - charge injected from the base 2, and further receives the injection of a - electrode from the base 2. As a result, the toner 12 exposed to the optical image is charged from the initial positive polarity to the opposite polarity, negative polarity. In this way, a static latent image is formed on the substrate 2 by toners of different polarities.

Next, while transferring the transfer sheet 5 in the direction of the arrow, the transfer charger 6 charges the toner portion 11 which has not been exposed to a light image to a negative polarity opposite to that of the +charged toner 11, which has not been exposed to a light image. The toner 11 is transferred onto the sheet 5 to obtain a positive optical image. A copy image is obtained by fixing this onto the sheet 5 using a heat roller 7 made of tetrafluoroethylene resin or the like. When the sheet 5 is charged to the same polarity as the -charged toner 11 that has been exposed to a photoimage, a +charged toner 1 that has not been exposed to a photoimage
2 is transferred onto the sheet 5 to obtain a negative optical image.

The toner is not limited to a single color such as black. It goes without saying that color copies can be obtained by coloring the toner in three primary colors and creating a mixed system consisting of a photoconductive material having a photosensitivity spectrum corresponding to each color. The toner used in the present invention does not need to be particularly new; for example, it may contain 3 parts by weight of phthalocyanine as a charge-generating pigment, 18 parts by weight of polyester resin as a binding resin, and 4-nitrochloride as a sensitizer. - 1 part by weight of phthalic anhydride. Examples of known antiblocking agents for toner include silica, alumina, and talc, and appropriate amounts thereof are added as needed.

In addition, in the transfer step of the present invention, in addition to the above-mentioned transfer charger, a known transfer device such as a transfer roller can be used.

Effects of the Invention: According to the recording method of the present invention, when exposing the charged photoconductive toner layer on the substrate to light image, since a bias potential is applied to the substrate, the exposure The charged polarity of the portion becomes opposite to the charged polarity of the unexposed portion. Therefore, either the exposed portion of the optical image or the unexposed portion of the optical image can be transferred onto the transfer sheet as desired, and either a positive image or a negative image of the optical image can be selectively obtained. Furthermore, by arranging a grounded conductive blade as a counter electrode to a conductive substrate to which a bias potential is applied, an electric field is generated between the substrate and the blade that directs the charged toner toward the substrate. Due to this action, toner adheres to the surface of the substrate, and the strength of the electric field rapidly decreases due to the shielding effect in the area where the toner layer is formed, but by moving the substrate relative to the blade,
Toner is subsequently deposited on the substrate to form a toner layer. As a result, a thin toner layer is uniformly and reliably formed on the substrate, thereby providing a good visible image.

Furthermore, since a bias potential is applied to the substrate to inject charges of opposite polarity into the exposed toner, it is extremely simple to simply provide a grounded conductive blade near the surface of the substrate. The above effect can be obtained.

[Brief explanation of the drawing]

1 and 2 are schematic front views of a recording apparatus to which a conventional recording method is applied, FIGS. 3 to 6 are process diagrams illustrating an example of the recording method of the present invention, and FIG. 7 is a schematic front view of a recording apparatus to which a conventional recording method is applied. 1 is a schematic front view showing an example of a recording device to which the recording method is applied. 1... Hopper, 2... Conductive base, 3... Conductive blade, 3G... Conductive magnetic blade, 4
...Optical system, 5... Transfer sheet, 6... Transfer charger, 8... Magnet, 10... Photoconductive powder toner, 11, 11G... Charged toner, 12, 12
G...Exposure toner.

Claims (1)

[Claims] 1. (a) triboelectrically charging photoconductive powder toner to a predetermined polarity, and (b) biasing a conductive substrate having a grounded conductive blade near its surface as a counter electrode. a step of applying a potential to charge the substrate to a polarity opposite to that of the charged toner; (c) adsorbing the charged toner onto the substrate to uniformly cover the surface of the substrate with a toner layer; (d) a step of uniformly covering the surface of the substrate with a toner layer; exposing the layer to a light image with a bias potential applied to the substrate; (e) injecting a bias charge of the substrate into the toner that has become conductive through the exposure so that the polarity of the toner is reversed; (f) transferring toner having a charge of one of the polarities among the toners on the surface of the substrate to a transfer sheet. recording method.