JPH049087A - wet recording device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

Detailed Description of the Invention [Industrial Field of Application] The present invention relates to a wet recording device that forms a toner image on an image carrier by electrophoresis using liquid toner and transfers it to a recording medium to form an image. Regarding.

[Prior Art] A recording device using a conventional intermediate transfer medium adhesively transfers a toner image on an image carrier to an intermediate transfer medium having adhesiveness and releasability, and then transfers the toner image from the intermediate transfer medium to a recording medium. (Ogasawara et al.: Adhesive melt transfer of toner images, Proceedings of the 4th Non-Impact Printing Technology Symposium (1987), p. 101-1.04)
).

[Problems to be Solved by the Invention] In the above-mentioned prior art apparatus, the primary transfer of the toner image on the image carrier to the intermediate transfer medium utilizes the adhesive force of the intermediate transfer medium. To prevent damage, the toner image on the image carrier must be dry. Therefore, the toner used is preferably a dry toner, and a liquid toner is not suitable. In other words, when liquid toner is used, the image carrier is wetted with not only toner particles but also a solvent component, so the solvent spreads during subsequent transfer to an intermediate transfer medium, resulting in image smearing. This had the problem of causing . In addition, since the toner was wet, the adhesiveness was reduced, and toner images were missing, resulting in a reduction in image quality. Furthermore, in order to achieve good transfer, it is necessary to provide a means for drying the liquid toner, which has the problem of complicating and increasing the size of the apparatus.

Therefore, the present invention aims to solve these problems.
The objective is to realize a wet recording device that can obtain high image quality even when using liquid toner.

[Means for Solving the Problems] A wet recording device of the present invention includes an image carrier on which a toner image developed with liquid toner is formed, an intermediate transfer medium to which the toner image is primarily transferred, and the intermediate transfer medium. and a pressure roll that comes into pressure contact with the medium via the recording medium to secondarily transfer the toner image onto the recording medium, and the intermediate transfer medium is made of a foamed elastic layer with a smooth surface. It is characterized by Further, the pressure roll is a heat roll containing a heat source.

[Function] In the above configuration of the present invention, the toner image on the image carrier also contains a solvent component, but in order to have only the solvent component absorbed by the countless pores of the foamed elastic layer by capillary action, intermediate transfer is performed. A toner image consisting only of toner particles is transferred onto the medium, and primary transfer can be performed without image collapse due to flow of solvent components. Furthermore, since the intermediate transfer medium has an elastic layer, it is possible to bring the toner image on the intermediate transfer medium into close contact with the uneven recording medium, and good secondary transfer can be performed regardless of the smoothness of the recording medium surface. be exposed.

[Example] Next, the present invention will be explained based on an example. FIG. 1 is a sectional view showing the configuration of a printer showing a first embodiment of the present invention. The figure shows an electrophotographic printer. Around the photosensitive drum 1, which is an image carrier, there are a charging device 2, an exposure device 3, a developing device 4, which are sub-process devices, an intermediate transfer drum 5, which is an intermediate transfer medium, a cleaning device 6, and a static eliminator 7. The body drums 1 are sequentially arranged in the rotational direction of the body drum 1. The toner image formed on the photoreceptor drum 1 through charging, exposure, and development steps is primarily transferred onto the intermediate transfer drum 5 by applying a transfer voltage from an external power source 11 . pressure roll 8
The recording paper 9, which is a recording medium to be conveyed, is brought into pressure contact with the intermediate transfer drum 5, and the toner image on the intermediate transfer drum 5 is secondarily transferred to the recording paper 9. . The toner and solvent remaining on the intermediate transfer drum 5 are collected by an intermediate transfer drum cleaning device 10. The recording paper 9 is further conveyed to a fixing device 12, and the toner image is fixed onto the recording paper 9 by heat and pressure. The liquid toner used in this example is composed of a negatively charged resin containing a pigment dispersed in an insulating carrier solvent.

Here, the intermediate transfer drum 5 is composed of a hollow metal drum 50 and a foamed elastic layer 51 covering the hollow metal drum 50, as shown in FIG. 2(a).

FIG. 5B is an enlarged view of the surface of the foamed elastic layer 51.

A countless number of circular holes 52 are opened in the depth direction from the surface, and the diameter is set to be sufficiently smaller than the toner particles.

The primary transfer of the toner image from the photoreceptor drum 1 to the intermediate transfer drum 5 is performed between the metal part of the photoreceptor drum 1 and the intermediate transfer drum 5.
A transfer voltage is applied between the external power source 11 and the metal hollow drum 50 to electrostatically perform the transfer. In this embodiment, the voltage was applied so that the intermediate transfer drum 5 side was positive. At this time, by making the surface of the foamed elastic layer 51 smooth, all of the toner images on the photosensitive drum 1 can come into contact with the intermediate transfer drum 5 without missing. Here, conventionally, the wet toner image formed on the photoreceptor drum 1 has been crushed due to the contact pressure with the transfer medium, but in the present invention, the intermediate transfer drum 50 has countless openings on the foamed elastic layer 51. Since the pores 52 in the toner image absorb the solvent component in the toner image, image collapse does not occur.

FIG. 3 is a diagram showing the state of primary transfer of a toner image. This will be explained in more detail using the figure. Photosensitive = 5- The toner image formed on the photosensitive drum 1 contains toner particles 13 and a solvent component 14, but 01 in the photosensitive drum 1.
1 When the transfer drum 5 comes into contact with the foamed elastic layer 5, only the solvent component 4 is absorbed into the pores 52 of the foamed elastic layer 5 due to capillary action.

For this reason, a toner image consisting only of toner particles 13 is transferred to the intermediate transfer drum 5'', and image smearing occurs due to the flow of the solvent component 14. Therefore, in the primary transfer, image loss and image collapse occur. The toner image on the photoreceptor drum 1 is faithfully transferred to the intermediate transfer drum 5 without coloring.

Next, in the secondary transfer from the intermediate transfer drum 5 to the recording paper 9, when the pressure roll 8 is brought into pressure contact with the intermediate transfer tram 5 via the recording paper 9, the foamed elastic layer 51 is applied to the recording surface of the recording paper, where the foamed elastic layer 51 is applied to the surface of the recording paper. The toner image is mechanically retransferred onto the recording paper 9 faithfully regardless of the smoothness of the recording paper 9. At this time, the intermediate transfer drum 5 contains the solvent component j-4.
Since the toner image without the toner image is primarily transferred, image deterioration due to bleeding of the solvent component [4] onto the recording paper 9 does not occur even in the secondary transfer. In addition, by bringing the pressure roll 8 into pressure contact with the intermediate transfer drum 5, the pressure roll 8 can be brought into contact with the intermediate transfer drum 5 without applying any special driving force to the pressure roll 8.
and follows without relative speed.

Therefore, the recording paper 9 that is conveyed through the intermediary sheet between the intermediate transfer drum 5 and the pressure roll 8 is also conveyed with no relative speed to the intermediate transfer drum 5, so that image deterioration during transfer due to unevenness in recording paper conveyance such as jitter is avoided. It becomes possible to prevent this. In the secondary transfer as well, it is possible to provide an electric potential difference between the pressure roll 8 and the intermediate transfer drum 5 and utilize electrostatic force auxiliary.

After the completion of the secondary transfer, the residual toner on the intermediate transfer drum 115 and the solvent component 1 absorbed into the pores 52 of the foamed elastic layer 51
4 is removed by an intermediate transfer drum cleaning device ]O.

FIG. 4 is a diagram showing cleaning of the intermediate transfer drum. An elastic plate ] 01 is brought into contact with the foamed elastic layer 51 to remove residual toner 100 on the intermediate transfer drum 5 . continue,
By pressing the metal roller 102 in the rotating direction of the intermediate transfer drum 5, the solvent component 14 absorbed in the pores 52 of the foamed elastic layer 51 is attached to the metal roller 02 and removed. Metal roller] Solvent component 14 attached to 02
J5 is attached to the peeling plate 103 that is in contact with the metal roller 102.
It will be peeled off. Residual toner 100 and solvent component 14
is removed, and the intermediate transfer drum 5 repeats primary transfer and secondary transfer again. The metal roller 102 can also be detachably attached depending on the operation of the intermediate transfer drum 5. In this case, by releasing the metal roller 102 from the pressed state when the intermediate transfer drum A5 is not rotating, deterioration of the foamed elastic layer 51 due to pressure can be prevented and the service life can be extended.

Next, the foamed elastic layer 51 will be described. As the material for the foamed elastic layer 510 of the present invention, in addition to foamed rubber exhibiting insulation properties such as polyurethane rubber, silicone rubber, and fluorocarbon rubber, foamed rubbers such as conductive polyurethane rubber and conductive silicone rubber that have been imparted with conductivity are also used. can do. By imparting conductivity to the foamed elastic layer 51, the effective dielectric thickness of the C1 foamed elastic layer 51 can be reduced to 0, allowing the primary transfer to be performed without impairing the mechanical elastic function in the secondary transfer. The transfer electric field can be emphasized.

FIG. 5 is a perspective sectional view of a pressure roll 8 used in a printer showing another embodiment of the present invention. Since the steps other than the secondary transfer step are the same as those in the first embodiment, the explanation will be omitted. In the figure, the pressure roll 8 has a cylindrical structure and includes a heat source 80 such as a ceramic heater or halogen lamp, and also has the function of a heat roll. By simultaneously applying electrostatic force, pressure, and heat during transfer, it is possible to fix the toner image onto the recording paper. , ] - By applying heat to the toner image, the resin component of the toner melts, which increases the releasability at the interface between the foamed elastic layer 51 and the toner image, and melts at the boundary between the recording paper and the toner image. death! ″::The toner force fills the gaps between the fibers of the recording paper.In other words, it is possible to perform transfer and fixing at the same time, and the conventional fixing device can be omitted.Also, at the same time, the foamed elastic layer 5
It also has the effect that 1 is absorbed and the solvent is volatilized.

Further, the intermediate transfer medium may not be in the form of a drum, but may be in the form of a belt with a foamed elastic layer having two continuous layers.

In this case, as in the first embodiment in which the intermediate transfer medium is drum-shaped, the secondary transfer is performed mainly by electrostatic force, and the secondary transfer is performed mainly by mechanical elastic force using a pressure roll. Further, it is also possible to perform transfer and fixing simultaneously by using a belt-shaped intermediate transfer medium and using a heat roll containing a heat source as the pressure roll as in the second embodiment.

[Effects of the Invention] As described above, according to the present invention, by using an intermediate transfer medium having a foamed elastic layer with a smooth surface, it has become possible to use liquid toner. In other words, in the second transfer, it is possible to faithfully transfer an image to the intermediate transfer medium without image loss or image collapse, and even in the second transfer, it is possible to transfer the image faithfully to the intermediate transfer medium without any blurring, regardless of the smoothness of the recording medium. This has the effect that a clear image can be obtained on the recording medium. Further, since the recording medium and the intermediate transfer medium are in close contact with each other during transfer and the recording medium is conveyed without relative speed, it also has the effect of preventing image deterioration during transfer that occurs due to uneven conveyance of the recording medium. Furthermore, by using a pressure roll containing a heat source, it is possible to perform fixing at the same time as the transfer, and there is also the effect that the fixing device can be omitted.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing the configuration of a printer showing a first embodiment of the present invention. FIG. 2(a) is a perspective sectional view of the intermediate transfer drum used in the first embodiment of the present invention. FIG. 2(b) is an enlarged view of the surface of the foamed elastic layer of the intermediate transfer drum used in the first embodiment of the present invention. FIG. 3 is a diagram showing the primary transfer of a toner image according to the present invention. FIG. 4 is a diagram showing an intermediate transfer drum cleaning device used in the first embodiment of the present invention. FIG. 5 is a perspective sectional view of a pressure roll used in a printer showing another embodiment of the present invention. ■ Photoreceptor drum 5 Intermediate transfer drum 8 Pressure roll Recording medium External power source Toner particles Solvent component Foamed elastic layer Pore heat source Above Applicant Seiko Epson Corporation Agent Patent attorney Kizobe Suzuki et al.

Claims (1)

[Claims] (1) An image carrier on which a toner image developed with liquid toner is formed, an intermediate transfer medium to which the toner image is primarily transferred, and a press contact with the intermediate transfer medium via a recording medium to transfer the toner image. A wet type recording apparatus having a pressure roll for performing secondary transfer onto the recording medium, wherein the intermediate transfer medium is composed of a foamed elastic layer having a smooth surface. (2) The wet recording device according to claim 1, wherein the pressure roll is a heat roll containing a heat source.