JPS62257178A - Printing device - Google Patents

Abstract

PURPOSE:To enable image formation by a simultaneous method and to perform transfer to normal paper by an electrostatic transfer method by providing plural insulating parts and conductive parts on a toner surface and using a (p) or (n) type semiconductor as a conductive material. CONSTITUTION:Plural independent insulating parts 25 are provided to the toner surface of a conductive part 24, the (p) or (n) type semiconductor is used as the conductive part, one of them is used according to the polarity of a photoconductor layer 3. A bias voltage 13 is applied to a sleeve 9 to implant a charge in toner 23 contacting an image forming body 4, and then an exposed and an unexposed part differ in the quantity of charge implantation, so there is a difference in electrostatic sticking force to the surface of the photoconductor layer 3, thereby forming an image. Then, a recording medium 17 is superposed upon the surface of the image forming body 4 and its reverse side is charged electrostatically by a corona transfer device 20 to the opposite polarity from the charge of the insulating parts 25 of the toner 7. Charges of the conductive parts 24 contacting the recording medium 17 are neutralized and an electrostatic force operates on the recording medium 17 owing to charges that insulating parts 25 holds, thereby carrying out the transfer.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a printing device that uses a photoconductor and uses so-called xerography technology, and more specifically, relates to a printing device that uses a toner with a special structure. The present invention relates to a printing device that utilizes new xerographic technology.

[Prior Art] In recent years, various printing devices using xerography technology have been put into practical use and used. To give an overview of the toners used in this technology, in the case of printing devices using the Carlson process, two-component magnetic brush development method and float electrode effect development method (FEED method) are used.
An insulating non-magnetic toner is used in , an insulating magnetic toner is used in jumping development, and a conductive magnetic toner is used in electrofax.

Recently, a method using new xerography technology that forms images by simultaneously performing exposure and development (hereinafter referred to as the "simultaneous method"), which has the potential to greatly simplify the process, has been studied in various places. For example, JP-A-58-15395
7 has been proposed.

According to this simultaneous method, the processes of a charger, a static eliminator, and a cleaner that are necessary in printing devices using conventional xerography technology are not required, and waste toner is not generated.
This simplifies the process and saves toner, making it possible to downsize the device and reduce costs. An overview of this simultaneous method is as follows:
The most suitable developing method is considered to be a method in which the surface of the image forming body containing the photoconductor layer is rubbed with a conductive magnetic I-ner brush to which a bias voltage is applied during exposure. There is a difference in the amount of charge injected into the toner that is in contact with the surface of the image forming body due to the bias voltage when it acts as an insulator (unexposed area) and when it acts as a conductor (exposed area). The difference in charge amounts results in a difference in electrostatic adhesion to the surface of the image forming body, making it possible to form a toner image.

[Problems to be solved by the invention] However, due to the conductivity of the toner used in the simultaneous method, the charge on the toner is neutralized in a short relaxation time, weakening its electrostatic adhesion to paper. Therefore, in the well-known electrostatic transfer method, the transfer rate to paper decreases. Particularly at high temperatures, the electrical conductivity of paper increases, causing charge injection of opposite polarity from the paper to the toner, resulting in the drawback that the well-known electrostatic transfer method cannot transfer to paper at all.

The object of the present invention is to provide a printing device using the simultaneous method, which does not have the above-mentioned drawbacks. Specifically, it is an object of the present invention to provide a toner that can form an image using a simultaneous method and can be transferred onto plain paper using an electrostatic transfer method.

[Means for Solving the Problems] The printing apparatus according to the present invention provides a plurality of insulating parts and conductive parts on the toner surface, and uses a p-type or n-type semiconductor as the conductive material. It is characterized by allowing only one type of charge injection, either positive or negative.

[Function] When the toner used in the printing apparatus of the present invention has the above-mentioned configuration, charge injection into the toner in contact with the surface of the image forming body during image formation in the simultaneous method is achieved through the positive or negative charge of the semiconductor which is the conductive material. This is done by charge injection due to the movement of negative carriers, and even if the injected charge is neutralized when the toner contacts the recording medium during electrostatic transfer, charge injection of the opposite polarity is not performed, so the toner is pre-charged. Electrostatic transfer can be performed by the electric charge of the insulating portion on the surface of the toner particles.

[Example] Fig. 1 (al, (b)) shows an example of the printing apparatus according to the present invention. Transparent conductor layer 2 on support 1
An image forming body 4 formed by laminating a photoconductor layer 3 and a photoconductor layer 3 is rotated in the direction of an arrow 5 by a roller 10. Reference numeral 6 denotes a toner supply device, and toner 7 is conveyed to the surface of image forming body 4 by a well-known magnetic brush composed of a magnetic roller 8 and a sleeve 9.

Also, at this time, the insulating part on the surface of the toner 7 is connected to the sleeve 9.
Alternatively, it can be charged as desired by a charging blade (not shown). The toner layer thus supplied is arranged to contact the image forming body 4 from the side opposite to the exposure side at the same time or immediately after the exposure 12 by the exposure device 11, and is placed between the transparent conductor layer 2 and the sleeve 9. Applied bias voltage 1
3 causes a difference in the adhesion force to the surface of the image forming body 4 between the exposed area and the non-exposed area, and as a result, selective toner adhesion occurs depending on the exposure, and an image is formed. The main components of the exposure device 11 include a self-focusing rod lens array 14, an LCS head substrate 15, and a line light source 16 made of a halogen lamp or a fluorescent tube.This LCS head is disclosed in, for example, Japanese Patent Laid-Open No. 193521-1983. . ]・The image forming body 4 on which the image has been formed is indicated by the arrow 5.
The recording medium 17 is fed from the direction of the arrow 19 by the conveyance roller 18 and is moving under the well-known corotron 20 facing the image forming body 4 at the same moving speed as the image forming body 4. During this time, the toner image is electrostatically transferred from the image forming body 4 to the recording medium 17. The thus formed image on the recording medium 17 passes through a well-known heat fixing roller 21, is fixed, becomes a printed matter, and is discharged in the direction of an arrow 22. After the transfer, the image forming body 4 again reaches the image forming section composed of the toner supply device 6 and the exposure device 11,
The next printing process begins, but by this time the residual toner remaining on the image forming body without being transferred has been neutralized in accordance with the relaxation time of the toner and the image forming body, and is electrostatically charged. It has been found that since the adhesion force is weakened, the toner is collected by the magnetic brush of the toner supply unit 6 and no previous history remains.

FIG. 2 shows details of how an image is formed in the printing apparatus according to the present invention. In the figure, the same elements as in FIG. 1 are given the same numbers. An image forming body 4 formed by laminating a photoconductor layer 3, a transparent conductor layer 2, and a transparent support layer 1 in this order receives image exposure 12 as it moves in the direction of an arrow 5.

The toner layer 23 is brought into contact with the image forming body 4 at the exposed portion by a well-known magnetic brush formed using a magnet roller 8 and a sleeve 9. Since a bias voltage 13 corresponding to the polarity of the conductive material of the toner is applied to the sleeve 9, the toner in contact with the image forming body 1 is charged with a charge according to the polarity of the bias voltage from the sleeve 9. is injected into the toner. At this time, the amount of charge injected is different between the exposed area and the unexposed area, resulting in a difference in the electrostatic adhesion force of the toner to the surface of the photoconductor layer 3, and image formation is performed.

FIG. 3 shows details of how images are transferred by the electrostatic transfer method in the printing apparatus of the present invention.

In the figure, the same elements as in FIG. 1 are given the same numbers.

A recording medium 17 is placed on the surface of the image forming body 4 on which a toner image has been formed, and the back side of the recording medium 17 is transferred by a corona transfer device 20 to a charged charge (
It is charged to the opposite polarity to the charge injected during image formation.

At this time, the electric charge of the conductive part in contact with the recording medium 17 and the conductive part electrically coupled to the conductive part is instantly neutralized, but the electric charge from the corona charger 20 is Since the polarity is opposite to that of the corona charger 20, it is possible to prevent further charge from being injected into the toner and charging the toner to the same polarity as the charge from the corona charger 20.

Therefore, electrostatic force acts as a transfer force between the toner 7 and the recording medium 17 due to the charge held by the insulating portion on the surface, and toner transfer is achieved.

FIG. 4 shows an example of the structure of toner used in the printing apparatus of the present invention. A plurality of independent toner surfaces on the conductive portion 24! ! It has a structure having edge property 25. As the conductive portion, either a p-type or n-type semiconductor is used depending on the polarity of the photoconductor layer 3. The insulating material 25 has a thickness of 1 to maintain sufficient insulation between the conductive parts 24.
Any toner material having a volume resistivity of 0.8 Ω·cm or more can be used. 26 is a fine powder of a well-known insulating magnetic material such as Fe 30a or γ-F13203, which is dispersed and blended in the insulating part 25. is necessary.

FIG. 5 shows still another example of the structure of the toner used in the printing apparatus of the present invention. In the figure, the same elements as in FIG. 4 are given the same numbers.

In this structure, p-type or n-type semiconductor fine powder is embedded in the surface of a well-known insulating toner, and even if the conductive parts are individual, the toner aggregate will probabilistically generate a large amount of current. Because of the presence of the channels, it behaves as a conductive toner during image formation. Such fine semiconductor powder can be easily obtained from the vapor generated by sputtering a p-type or n-type Si single crystal, and a conventional insulating toner can be used for toner having a zero-strand structure. A conductive toner having desired chargeability can be easily obtained.

[Effects of the Invention] As described above, the printing apparatus according to the present invention uses a toner having a structure in which the surface of the toner has a plurality of insulating parts and a conductive part made of a semiconductor in a printing apparatus using a simultaneous method. By using it, it is possible to obtain good electrostatic transfer, especially at high temperatures, which is previously impossible, and it is included in the printing cycle compared to printing devices using conventional xerography technology. It is possible to provide a small, low-cost printing device that greatly reduces the number of steps.

Note that the image forming body used in the printing apparatus of the present invention can be used as a belt with a seam or a belt without a seam.
If there is no seam, the circumferential length of the belt can be shortened regardless of the printing length, which leads to further downsizing of the apparatus.

Further, the toner conveyance means of the toner supply device of the printing apparatus according to the present invention is not limited to only a magnetic brush, and for example, a brush conveyance using a brush made of conductive fibers is also possible. In this case, it is not necessary to contain a magnetic component in the toner, and a magnet roller, which is an expensive component, is not required, which is further advantageous in terms of cost.

[Brief explanation of drawings]

FIGS. 1(a) and (b) are diagrams showing an embodiment of the printing device according to the present invention, FIG. 2 is a diagram showing details of how image formation is performed in the printing device according to the present invention, and FIG. FIGS. 4 and 5 are diagrams showing how toner is transferred by the electrostatic transfer method in the printing device of the invention. FIGS. 4 and 5 are diagrams showing examples of the structure of toner used in the printing device of the invention. 1 - Transparent support 12 - Exposure 2 - Transparent conductor layer 13 - Bias voltage 3 - Photoconductor layer 17 - Recording medium 4 - Image forming body 20 - Corotron 6 - Toner - 7 - Toner 24 - Conductive part 1 1 - Exposure device 25-Insulating materials and above Applicant Seiko Epson Co., Ltd. Agent Patent attorney Tsutomu Mogami et al. 4 Figure 1 Figure 5 24 4 Denshu

Claims (3)

[Claims] (1) On an image forming body comprising a photoconductor layer, the photoconductor layer is exposed to light, and at the same time or immediately after the exposure, a toner layer is brought into contact with the image forming body from the side opposite to the exposed side. By applying an electric field to the photoconductor layer and the toner layer, the toner is selectively attached to form an image, and the toner image is transferred from the image forming body to the recording medium to produce a printed matter. A printing device for producing a toner is characterized by having a structure in which a plurality of insulating parts and a plurality of conductive parts are provided on the surface of the toner, and using a p-type or n-type semiconductor as the conductive material of the toner. Printing device. (2) The printing device according to claim 1, wherein the toner has a structure including a plurality of independent insulating parts within the conductive part. (3) The printing device according to claim 1, wherein the toner has a structure including a plurality of independent conductive parts within an insulating part.