JPS63135956A - Printing method - Google Patents

Abstract

PURPOSE:To improve transfer property and to enable transfer to be performed especially in a high humidity state, by using mixed toner in which a conductive toner and a insulating toner are mixed. CONSTITUTION:Exposure is applied on an image forming body including a photoconductive layer, and the toner in which the conductive toner having a resistivity <=10<8>OMEGAcm and the insulating toner having a resistivity >=10<9>OMEGAcm and where charging polarity and a charging quantity are controlled, are mixed in a ratio of the conductive toner to the insulating toner 1:0.1-10 is brought into contact with the image forming body from a side opposite to an exposure side. And a developing bias voltage is applied between the photoconductive layer and a toner supplying apparatus, and a toner image is formed by attaching the toner on the image forming body, and after that, a recording medium is superposed on the toner image, and an electric field by which an electrostatic force can act on the insulating toner from the image forming body in a direction of the recording medium, and the toner image is transferred from the image forming body to the recording medium, then, the toner on the recording medium is fixed. In such way, it is possible to perform the transfer on a sheet of plain paper with an electrostatic transfer method even in the high humidity state.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a printing method using a photoconductor and, in particular, a printing method using a special toner. This paper relates to a printing method that utilizes new xerographic technology.

[Conventional technology]

In recent years, various printing methods 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 methods using the "Carlson process", insulating non-magnetic toners and jumping In the development method, an insulating magnetic toner is used, and in the case of electrofax, a conductive magnetic toner is used.

In addition, a method using the unique xerography technology (hereinafter referred to as the "simultaneous method") that simultaneously performs exposure and development to form an image, which has the potential of greatly simplifying the process, has been proposed in many places. For example, Chishishi → 1980-1539
57 has been proposed.

This simultaneous method eliminates the need for the charger, remover, and cleaner processes that are required in conventional xerographic printing methods, and also eliminates waste toner, which simplifies the process. Toner can be saved, and the device can be made smaller and lower in cost. To give an overview of this simultaneous method, it is considered that the optimum developing method is a method in which a brush of 5 taaa toner to which a bias voltage is applied during exposure is used to rub the surface of a painter's body comprising a photoconductor layer T-. , when the photoconductor acts as an insulator (no exposure ll5);
There is a difference in the amount of charge injected into the toner that is in contact with the surface of the III image forming body due to the bias voltage depending on when it acts as a conductor (the exposed area), and the difference in the amount of charge is caused by It becomes possible to form a toner image due to the difference in electrodeposition force of t#.

[Problem that the invention seeks to solve]

However, due to the conductivity of the toner used in the simultaneous method, when it comes into contact with the transfer paper, the charge injected during image formation is quickly lost, and the electrostatic adhesion force with the paper weakens. The well-known 1-transfer method has the disadvantage that it cannot be transferred to paper sufficiently. Particularly in high humidity, the resistance value of paper decreases, so toner injection 1! The charge is rapidly lost, and eventually a so-called Blowoff phenomenon occurs, in which charge of the opposite polarity is injected from the paper to the toner, causing the toner once transferred to the paper to fail. In effect, it was a transcription of Fumachi Inume.

The object of the present invention is to provide a printing method using the simultaneous method, which does not have the above-mentioned drawbacks. Specifically, the object is to provide a toner that has I'IT capability for image formation by a simultaneous method and can be transferred to plain paper by an electrostatic transfer method even in high humidity conditions.

[Means for solving problems]

The printing method in the present invention comprises II! A conductive toner with a resistivity of 108- or less and a conductive toner with a resistivity of 109- or more are applied to the surface of the film from the opposite side of the exposure at the same time or immediately after the exposure.
Insulating toner with controlled conductivity and charge amount in a weight ratio of 1 to 1 insulating toner.
A toner made of a mixture having a ratio of 0.1 to 10 is brought into contact with the image forming member by a toner supply device, and a current bias voltage is applied between the main electric body 11 and the toner supply device.
After applying one pressure and selectively adhering the toner onto the image forming body to form a toner image, a recording medium is placed on the toner image, and an electrostatic force is applied to the insulating toner in the direction from the image forming body to the recording medium. The method is characterized in that after the toner image is transferred from the image forming body onto the recording medium by applying the toner image, the toner on the recording medium is fixed.

[Effect]

When the toner used in the printing method of the present invention has the configuration shown in 8C above, during image formation, the image is formed through the droplets of conductive toner, which are stochastically always present, from the toner supply device to the image forming body. The conductive toner that comes into contact with the body
According to the original! # is injected by the development bias voltage. This difference in the amount of charge injected causes a difference in the electrostatic adhesion force of the toner to the surface of the image forming body, and a toner image is formed by a mixed toner of a conductive toner and an insulating toner on the image forming body. During transfer, an electric field is applied that causes an electrostatic force to act on the insulating toner in the toner image in the direction from the 1IiI image forming body to the recording medium. The image is transferred onto a recording medium according to the principle. At this time, transferability is guaranteed even in high humidity conditions due to electrostatic transfer of insulating toner.

〔Example〕

FIG. 1 (aL(1)) shows an embodiment of the printing method according to the present invention. Figure (a) is an overall view, and figure (1) is an enlarged view of the main parts. An image blurring body 4, which is formed by laminating a transparent area layer 2 and a quaternary conductor layer 3 on a belt-like transparent support 1, is rotated in the direction of an arrow 5 by a roller 10. Reference numeral 6 denotes a toner supply device, in which a mixed toner 7 of a quaternary toner and an insulating toner is conveyed onto the surface of the sub-image forming member 40 by a well-known magnetic brush composed of a magnet roller 8 and a sleeve 9. Toner Inri thus supplied, exposure a
It is arranged to contact the image forming body 4 from the side opposite to the exposure device at the same time as or immediately after the exposure 12 by 11, and the developing bias C1 pressure 15 applied between the transparent 41 section layer 2 and the sleeve 90. This action causes a difference in the adhesion force to the next surface of the image-forming body 4 between exposed and non-exposed areas, and as a result, selective toner adhesion occurs in response to exposure, forming an l1lji image. The exposure device 11 mainly includes a self-focusing rod lens array 14, an LOS head substrate 15, and a linear source 16 consisting of a halogen lamp or a fluorescent tube. Regarding this LC8 head, for example, Japanese Patent Application Laid-open No. 58
-193521. The image forming body 4 on which the toner image 1 has been formed moves in the direction of the arrow 5, and the recording medium 17 is fed from the direction of the arrow 19 by a conveying roller 18 to a well-known corotron 20 facing the image forming body 4.
While moving under the image forming body 4 at the same moving speed as the image forming body 4, one toner image is electrostatically transferred from the image forming body 4 to the recording medium 17. The toner image thus formed on the recording medium 17 passes through a well-known five-way thermal fixing roller 21, is fixed, becomes a printed matter, and is discharged in the direction of an arrow 22. After the transfer, the image formed by the image forming body 4d, the toner supply device 6, and the exposure device 11 reaches the storage section again and enters the next printing process, but remains on the image forming body without being transferred. By this time, the residual toner has been neutralized according to the relaxation time of the toner and the image forming body, and the electrostatic adhesion force has weakened, so the residual toner is collected by the magnetic brush of the toner supply device 6, and the remaining toner is collected by the magnetic brush of the toner supply device 6. It is clear that there is no remaining.

FIG. 2 shows details of how an image is formed in the printing method of the present invention. In the figure, the same elements as in FIG. 1 are given the same numbers. The image forming body 4, which is formed by laminating the transparent support 1, the transparent conductor 111i2, and the original four-conductor layer 3 in this order, is subjected to image exposure 12 when moving in the direction of the arrow 5. A well-known magnetic brush formed using a magnet roller 8 and a sleeve 9 causes the mixed toner 7 of the conductive toner 24 and the insulating toner 25 to come into contact with the image forming body at the exposure portion. A developing bias voltage 13 is applied to the sleeve 9.
is applied, charges are injected into the conductive toner in contact with the image forming body 4 through a current path formed by the contact between the conductive toners 24 .

This current path changes from time to time according to the mutual positional relationship of the toners that changes as the mixed toner 7 moves on the sleeve 9, and the toner flows from the sleeve 9 to the valley 4 in contact with the image forming body 4. There are probabilistically multiple current paths, and the above charge injection occurs reliably.

At this time, the charging polarity of the insulating toner 25 is 4 during image formation.
Note: Since the insulating toner material is selected so that the polarity of the charge injected into the toner 24 is opposite (in this example, positive), the conductive toner is An electrodynamic attraction force is generated between the toner 24 and the insulating toner 25, and the nine conductive toner 24 receives the charge injection.
1iil When the toner is attached to the next surface of the image forming body 4, the insulating toner 25 is also attached, and the conductive toner 1j is deposited on the image forming body 4.
A toner image is formed using the mixed toner 7 of the L note toner 24 and the insulating toner 25.

FIG. 3 shows details of how the image is transferred by the electrotransfer method in the printing method of the present invention.

In the figure, the same elements as in Figure 1 are given the same designations.

A recording medium 17 is placed on the narrow side of the image forming body 4 on which a toner image has been formed, and from the back side of the recording medium 17, ions with a polarity opposite to that of the electrical charge of the insulating toner 25 (in this embodiment) are applied by a corona transfer device 20. negative ions) are implanted. As a result, an electric field is generated in which an electrostatic force acts on the insulating toner 25 in the direction from the squadron forming body 4 toward the recording medium 17, and the insulating toner 25 in the toner m image is transferred according to the normal electrostatic transfer principle. The image is transferred onto the recording medium 17 according to the image data. For the conductive toner 24 in the toner image, the recording medium 1
7 acts in the direction of the image forming body 4, there is no transfer action by the corona transfer device 20, but the conductive toner 24 is transferred together with the insulating toner 25 due to the binding force with the conductive toner 24. Some things have been observed in experiments.

The conditions to be satisfied by the mixed toner of a conductive toner and an insulating toner used in the present invention will be described below.

During image formation, it is necessary for the electrical charge corresponding to the exposure to be quickly injected into the conductive toner in contact with the image forming body through the rows of conductive toner from the toner supply device to the image forming body. Because there is 41! There is an upper limit to the electrical resistance value of the toner. In experiments, the upper limit of the resistivity of 4711 toner was found to be 7M, which is one order of magnitude smaller than the resistance value of toner, which is generally called low-resistance toner. No image was formed when using the toner of Example 1.

Also, during transfer, the insulating toner in the toner image is silent.
In order to be transferred, the electrical resistance value of the -insulating toner needs to be high to some extent. In experiments, it has been confirmed that the resistivity of insulating toner is 10" 0 as the lower limit. If the resistivity is smaller than this, the resistivity of insulating toner will be the same as when electrostatically transferring conductive toner. , transcription became unnecessary.

Furthermore, regarding the mixing ratio of the conductive toner and the insulating toner, if the mixing ratio of the insulating toner to the conductive toner is too large, 4it
Sex toner. N'' where the conductive toner stream is present from the toner supply device to the image forming body.
4 also decreases, making it difficult to form an image. vice versa,
If the mixing ratio of insulating toner to conductive toner is too small, the insulating toner contained in the formed toner image. Since the ratio decreases by 1 to 10, the amount electrostatically transferred to the recording medium is reduced, and an image with the desired density cannot be obtained. We conducted various experiments by changing the mixing ratio of conductive toner and insulating toner, and found that conductive toner C1
~10 was an acceptable range.

Typical examples of the composition of the mixed toner used in the embodiments of the printing method of the present invention are shown below.

〔composition〕

Conductive toner: Resistivity 10Ω National average particle size 1G Am Maximum magnetization 40 emu/g Insulating toner: Resistivity 1014Ω Return polarity Plus average particle size 10 μm Non-magnetic weight mixture ratio: Insulating to conductive toner 1 Toner 2: When the mixed toner having the above configuration was used, good results were obtained in both image formation and transferability.

〔Effect of the invention〕

As described above, the printing method according to the present invention improves the transferability, which was a problem in the simultaneous printing method, by using a mixed toner of a four-pole toner and an insulating toner. This made it possible to perform transfers that were previously impossible, especially in high humidity conditions. Also,
As a result, it is possible to provide a small, low-cost printing device that significantly reduces the number of steps included in a printing cycle compared to a printing method using conventional xerography technology.

In the present invention, when a magnetic brush composed of a magnetic roller and a sleeve is used as a toner supply device, at least one of the conductive toner and the insulating toner must have magnetism. In the case of a combination of a conductive toner and a non-magnetic insulating toner, the action of force makes it easier to form streaks of conductive toner from the sleeve to the image forming body, making it more effective for image formation. It is. 2 It is also possible to make both conductive toner and insulating toner magnetic, and in this case, A
Since the noise force acts as a binding force between the m-type toner and the insulating toner, the adhesion rate of the insulating toner to the toner image is improved, and the loss of the printed matter can be increased. In addition, the binding force between the conductive toner and the insulating toner during image formation is ``a magnetic force,'' as well as chemical force, mechanical force, etc., or some of them. It may be made to occur in the form.

It is also possible to use a brush feeder using a brush made of conductive fibers as a toner feeder. This is advantageous in terms of cost since the rollers become unstable.

Note that the coloring agent for visualizing the image does not need to be included in both the conductive toner and the insulating toner, and it is sufficient that it be included at least in the background toner. It is clear from the principle.

Further, the image forming body used in the present invention can be used as a belt with a seam or a belt without a seam, but if the belt is without a seam, the belt length can be shortened regardless of the printing length, which leads to further downsizing of the apparatus. moreover,
lIJjw forming body @ forming body 44 which coats a thin film layer with frontal electrical resistance value and mechanical strength has printing durability and I
i! It is effective for improving the stability of 1i-branch formation.

[Brief explanation of the drawing]

Figures 1(a) and (kl) are diagrams showing an example of the printing method according to the present invention, and Figure 2 is a diagram showing the details of the RF/B printing method and image formation in the present invention. FIG. 5 is a diagram showing details of bodies transferred by electrostatic transfer in the printing method of the present invention. 1... Transparent support 2... Transparent conductor 1 body No. 5
... Original 4-electric body r4 4... Image forming body 6...
Toner supply device 7...Mixed toner 8...Magnetic roller 9...Sleeve 10...Roller
11... Exposure layer 12... Exposure 13.
...Bias voltage 17...Recording medium 18...
・Transport roller 20... Corotron 21...%
”＆N Low 524...4-color toner 25...
・Regional relationship 1 month or more Applicant: Seiko Epson Corporation 7〕・− Agent: Patent attorney Hide Mogami and 1 other person Figure 1

Claims (3)

[Claims] (1) An image forming body comprising a photoconductor layer is exposed to light, and at the same time or immediately after the exposure, a conductive toner having a resistivity of 10^6 Ωcm or less and a resistivity of A toner composed of an insulating toner having a resistance of 10^6 Ωcm or more and having controlled charge polarity and charge amount at a weight mixing ratio of 0.1 to 10 parts of the insulating toner to 1 part of the conductive toner. A toner supply device is brought into contact with the image forming body, and a development bias voltage is applied between the photoconductor layer and the toner supply device to selectively deposit the toner onto the image forming body to form a toner. After forming the image, a recording medium is placed over the toner image, and an electric field is applied to the insulating toner in a direction from the image forming body toward the recording medium to form the toner image. After transferring onto the body or onto the recording medium,
A printing method characterized by fixing toner on the recording medium. (2) The printing method according to claim 1, wherein at least one of the conductive toner and the insulating toner has magnetism. (3) The printing method according to claim 1, wherein the charged polarity of the insulating toner and the polarity of the charge injected into the conductive toner during image formation are opposite in polarity.