JPH08300719A - Electrostatic printer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an efficient and compact electrostatic printing apparatus by simple constitution wherein a particle flow modulating electrode member and a back electrode arranged in opposed relation thereto are provided, and a pressure member is provided in close vicinity to the surface of the back electrode in opposed relationship. SOLUTION: A toner supply source in which lumps T of toner particles are stored in close vicinity to a rotatable toner roller 103 is provided, and toner particles are given static charge by the frictional contact with the toner roller 103. Some charged toner particles are separated from the toner roller 103 to flow to the aperture part 113 of a particle flow modulating electrode member 120 to reach a back electrode 130. The modulating electrode member 120 and the back electrode 130 are controlled in power supply by a control circuit, and the flow of charged particles is deflected when it passed through the predetermined one aperture among a plurality of the apertures of the aperture part 113 to form an image. This image is transferred to a recording medium P under the pressure of a pressure member 140 such as a roller.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION This invention relates generally to the field of printers, and more particularly to the field of electrostatic printers.

[0002]

Printers are popular in both offices and homes. Printers that employ electrophotographic printing processes, such as laser printers, are particularly popular because they provide high print quality at an affordable price. Unfortunately,
The electrophotographic printing process requires relatively complex and bulky equipment. According to the teachings of the prior art, there are six stages in the electrophotographic printing cycle:

In the first step, a photoconductor such as a selenium drum or an organic photoconductor drum is charged. In the second step, the photoconductor is selectively discharged using a scanning laser beam to create a latent image. The space required for the laser beam scanning optics and the scanning beam path greatly affects both the size and complexity of the electrophotographic printer.

In the third step, the latent image is developed using charged toner particles that are electrostatically attracted to the latent image on the photoconductor to produce a toner image. It should be particularly noted that electrophotographic printer imaging is indirect, as the toner image is not formed until a latent image is formed. Therefore, there is no direct toner imaging method performed by electrophotographic printing.

In the fourth step, the toner image is transferred to paper.
In the fifth step, the pair of fusing rollers apply heat to fix the toner image on the paper. In step 6, the photoconductor is cleaned so that the cycle can be repeated.

While these six steps have become very sophisticated in recent years, the complexity and bulk of electrophotographic printers remains largely unchanged. One way to reduce the complexity and bulk of the prior art is to simplify printing by eliminating steps. For example, the steps can be reduced by omitting the photoconductor. However, the fact that most electrophotographic printers today hold the complete 6-cycle stage proves that it is difficult to omit any of the stages.

Another limitation of prior art electrophotographic printers is that the fusing roller is located remotely from the photoconductor to provide thermal insulation therefrom. Thermal isolation has been found in the prior art because the photoconductor can be damaged by heat and because the photoconductor configuration is optimized for its photoconductive function without receiving heat from the fusing roller. Has been adopted.

The distant placement of the fusing element can disadvantageously increase the size of the printer and adversely affect print quality. In particular, before the toner image is fused by the fusing roller, the charged toner particles of the toner image have a chance to repel each other, possibly increasing the size of the toner dots and degrading the print resolution. As the installation distance of remote installations of printing elements increases, so does the opportunity to reduce print quality.

[0009]

Although the prior art has a number of advantages, the size and complexity difficulties still remain. Due to the difficulties associated with the photoconductor described earlier in this document, a simpler, more direct way of creating a toner image,
It is desirable to somehow eliminate the photoconductor. In addition, a more compact configuration is desirable because of the difficulties associated with remote placement of the fusing element.

All that is needed is a simple to use fusing roller placed in close proximity and direct toner imaging,
It is an efficient and compact electrostatic printing method.

[0011]

SUMMARY OF THE INVENTION The present invention provides a simple, efficient, and compact electrostatic printing process that uses a closely located fusing roller and direct toner imaging. Therefore, the present invention eliminates the burden of space required for the photoconductor, the laser beam scanning optics, and the scanning beam path, which is a major contributor to both the size and complexity of prior art electrophotographic printers. . Further, the present invention does not have the burden of increasing the size of the printer and distantly installing the fusing element which affects print quality, as in the prior art.

Briefly and in general terms, the present invention comprises a toner source for supplying charged toner particles, and a particle flow modulating electrode member having an opening portion having a plurality of openings. There is. The present invention further comprises a back electrode placed in opposed relation to the surface of the modulation electrode member.
A control circuit applies a controlled electrical signal to the modulating electrode member and the back electrode to cause a stream of charged toner particles to flow through the predetermined one of the openings toward the back electrode.

A pressure member such as a roller is installed in close proximity to the surface of the back electrode in a facing relationship, and a recording medium such as a paper sheet sandwiched between the back electrode and the pressure member directly faces the recording medium. The position is such that it is pushed between the pressure member and the back electrode. In the preferred embodiment, a heating circuit is coupled to the back electrode to heat the back electrode to a temperature high enough to melt the charged toner particles. In an alternative embodiment, the heating circuit is coupled to the pressure member to heat the pressure member.

Such close proximity of the toner-melting components contributes significantly to the required simplicity of the present invention.
Further, according to the principles of the present invention, print quality is improved by the close placement of the fusing elements, as the charged toner particles have little opportunity to repel one another before fusing.

Other aspects and advantages of the present invention will become apparent from the following detailed description, taken in connection with the accompanying drawings, which illustrates by way of example the principles of the invention.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT As illustrated in FIG. 1 and subsequently described in detail herein, the present invention provides an efficient and compact static image by using a proximity mounted fusing element and by using direct toner imaging. We provide electro-printing method. FIG.
Shows a sectional side view of a partial schematic view of a preferred embodiment of the present invention. For illustration purposes, a conceptual combination of mutually perpendicular x, y, and z axes is depicted in FIG. 1, with the understanding that the x axis extends outwardly from the two-dimensional side view page of FIG. To be done.

The toner supply source supplies charged toner particles. For example, as shown in FIG. 1, a mass T of toner particles is stored in proximity to a rotatable toner roller 103, and the surface of the toner roller engages with the toner particles as the toner roller rotates. . The frictional contact with the toner roller causes the toner particles to collect an electrostatic charge. Some of the charged toner particles leave the toner roller and flow toward the opening 113 of the particle flow modulation electrode member 120 in the y-axis direction.

The opening portion 113 of the particle flow modulation electrode member 120 has a plurality of openings. FIG. 1 shows a cross-sectional side view of one of the openings. The electrode member is generally a suitable rectangular plate-shaped member, and includes an insulating layer 121, a reference electrode layer 122, and a control electrode 123.
Equipped with an array of. The reference electrode 122 is formed on the first surface of the two opposing main surfaces of the insulating layer 121 and is provided on the toner roller 103 side, and the array of the control electrodes 123 is different from the two opposing main surfaces of the insulating layer. Of elongated parallel strips extending in the z-axis direction and extending in the z-axis direction and spaced from each other in the x-axis direction. x-axis direction and z
In the axial direction, an xz plane parallel to the plane of the insulating layer 106 is formed.

The particle flow modulation electrode member 120 has a large number of openings arranged in a row in the middle portion thereof as viewed in the z-axis direction. Each opening is formed through one of the insulating layer 121, the reference electrode layer 122, and the control electrode 123.

As shown in FIG. 1, the present invention further includes a back electrode 130 which is disposed in a facing relationship with the main surface of the modulation electrode member and the toner electrode 103. In a preferred embodiment, the back electrode has an outer surface and, further, substantially decapsulates the outer surface of the drum, such as a silicone rubber or alternatively known as Teflon, such as polyvinyl fluoridin, to facilitate toner release. It comprises a rotatable conductive drum, such as an aluminum drum having a thin layer of plastic, for example about 25 microns thick. For simplicity, the toner release promoting plastic layer is not shown in FIG.

The control circuit applies a controlled electric signal to the modulation electrode member and the back electrode so that the flow of the charged particles flows toward the back electrode in the y-axis direction through one predetermined opening. For example, as shown in FIG. 1, the reference electrode layer 12
2 is connected to the ground, but each one of the control electrodes 123 is electrically connected to the modulation signal source indicated by S in FIG.
Since the back electrode is electrically connected to the high voltage source HiV, the flow of charged toner particles that is first selected by the modulating signal source to flow through the aperture is then back electrode 130.
Electrostatically attracted to, as the drum rotates,
Charged toner particles are deposited on the drum surface of the back electrode. Therefore, in the preferred embodiment shown in FIG. 1, the toner image is applied directly to the drum surface of the back electrode 130 as the drum rotates. Although FIG. 1 illustrates toner particles from a single toner source deposited on the back electrode, the present invention instead uses a plurality of different colored toner sources to add a color toner image directly to the back electrode. It is to be understood that it is not strictly limited to a single toner source as it can be.

A pressure member 140 such as a roller is attached to the back electrode 130.
The recording medium P, such as a paper sheet, which is installed close to the surface of the recording medium and faces each other in the z-axis direction, is sandwiched between the back electrode 130 and the pressure member 140, and the recording medium P is directly opposed to the recording medium. It is adapted to be pressed between the pressure member 140 and the surface of the back electrode 130. As the recording medium moves in the z-axis direction, the toner image is transferred from the drum surface of the back electrode to the surface of the recording medium and is fused to the recording medium by the heat flowing through the back electrode.

In the preferred embodiment, the heating circuit is thermally coupled to the back electrode to heat the back electrode to an elevated temperature sufficient to melt the charged toner particles. For example, in the preferred embodiment shown in FIG. 1, the heating circuit includes a thin film resistor 150 that is thermally coupled to the back electrode. A thermally controlled current source I is electrically coupled to the thin film resistor 150 to maintain the resistor and back electrode at the proper temperature. However, the present invention is not strictly limited to heating circuits that use thin film resistors, as alternative heating circuits that are thermally coupled to the back electrode can be used to obtain beneficial results. You should understand that. For example, an alternative embodiment uses a quartz heat lamp instead of a thin film resistor. In another preferred embodiment, the heating circuit is coupled to the pressure member to heat the pressure member. Such close proximity of the toner-melting components contributes significantly to the required simplicity of the present invention.

FIG. 2 shows a cross-sectional side view of a partial schematic view of an alternative embodiment of the present invention. For illustration purposes, the mutually perpendicular x,
A conceptual combination of y and z axes is shown in FIG. In an alternative embodiment, a plurality of different toner sources provide different color charged toner particles. For example, as shown in FIG. 2, a mass of yellow toner particles T _Y , a mass of magenta toner particles T _M , and a mass of cyan toner particles T _C are stored near each rotatable toner roller 203, As the toner roller rotates, the toner roller can engage the toner particles. The frictional contact with the toner roller causes the toner particles to collect an electrostatic charge. Some of the charged toner particles leave the toner roller and flow in the y-axis direction toward one opening 213 of each of the plurality of particle flow modulation electrode members 220.

The opening portion 213 of the particle flow modulation electrode member 220 has a plurality of openings. FIG. 2 shows a cross-sectional side view of each one of the openings in each electrode member 220. Each electrode member is generally
1 is a plate-like member having a respective array of respective insulating layers 221, respective reference electrode layers 222, and control electrodes 223, similar to that described in detail hereinabove with respect to the preferred embodiment of FIG. .

As shown in FIG. 2, the present invention further includes a back electrode 230 disposed in a facing relationship with the main surface of each modulation electrode member and the toner roller. In the alternative embodiment shown in FIG. 2, the back electrode comprises a flexible rotatable conductive belt of stainless steel or, alternatively, of polyimide coated with a layer of aluminum about 300 to 500 nanometers thick. The belt of the back electrode 230 is the particle flow modulation electrode member 220.
However, it is installed at a sufficient distance from the modulation electrode member so as to provide a space through which the recording medium P such as a paper sheet is fed along the feeding path as the belt rotates. .

The control circuit applies a controlled electrical signal to the modulating electrode member and the back electrode and causes a stream of charged toner particles to flow in the y-axis direction toward the back electrode through a predetermined one of the openings. For example, as shown in FIG. 2, the reference electrode layer of each member is connected to ground, but each one of the control electrodes is electrically connected to a respective modulation signal source, designated S _Y. It controls the yellow toner, controls the magenta toner designated S _M , and controls the cyan toner designated S _C. The back electrode is electrically connected to the high voltage source HiV so that the flow of charged toner particles initially selected by the modulation signal source to flow through the aperture of each modulation member is then electrostatically applied by the back electrode. Attracted, causing the charged toner particles to deposit on the surface of the recording medium as it moves along the feed path. Therefore, in the alternative embodiment shown in FIG. 2, the color toner image is applied directly to the surface of the recording medium P as the recording medium moves along the feed path. While FIG. 2 shows toner particles deposited directly on the recording medium, in another alternative embodiment the belt of the back electrode is substantially coated with toner release promoting plastic so that the toner particles are backed before being transferred to the recording medium. It is to be understood that the present invention is not strictly limited by this embodiment as it is first deposited on the belt of electrodes.

In the embodiment shown in FIG. 2, a pressure member 240 such as a roller is installed in close proximity to the surface of the back electrode in a facing relationship, and a recording medium moving in the z-axis direction is placed between the back electrode and the pressure member. It is sandwiched between the pressure member 240 and the back electrode 230 at a surface position directly opposite to the recording medium. As the recording medium moves in the z-axis direction, the toner image is fused to the recording medium by the heat flowing through the pressure member 240.

In an alternative embodiment, the heating circuit is thermally coupled to the back electrode to heat the pressure member to a suitable temperature high enough to melt the charged toner particles. For example, in the alternative embodiment shown in FIG. 2, the heating circuit comprises a thin film resistor 250 thermally coupled to the pressure member 240. A thermally controlled current source I is electrically coupled to the thin film resistor 250 to maintain the resistor and pressure member at the proper temperature. In another alternative embodiment, the heating circuit is coupled to the back electrode belt to heat the area of the back electrode belt.

The present invention provides a simple, efficient, compact electrostatic printing process that uses a closely located fusing element and uses direct toner imaging. While particular embodiments of the present invention have been illustrated and illustrated, it is not intended that the invention be limited to the particular forms or arrangements of parts so described and illustrated.

The embodiments of the present invention have been described above in detail, but examples of each embodiment of the present invention will be shown below.

[Embodiment 1] A toner source for supplying electrostatically charged toner particles, a particle flow modulation electrode member having an opening portion having a plurality of openings, and the modulation electrode member remote from the toner source. A controlled electric signal is applied to the back electrode, the modulation electrode member, and the back electrode, which are installed in a relationship facing each other, and the flow of the charged toner particles is passed through one of the openings toward the back electrode. The control circuit that flows to the back surface of the pressure electrode and the surface of the back electrode are placed close to each other in an opposing relationship, and the recording medium sandwiched between the back electrode and the pressure member has a direct contact between the pressure member and the back electrode. An image recording device comprising: a pressure member adapted to be pressed between the surface and the surface.

[Embodiment 2] The image recording apparatus according to Embodiment 1, further comprising a heating circuit which is coupled to the back electrode and heats the back electrode to a temperature high enough to melt the charged toner particles.

[Embodiment 3] The image recording apparatus according to Embodiment 1, further comprising a heating circuit which is connected to the pressure member and which heats the pressure member to a temperature high enough to melt the charged toner particles.

[Embodiment 4] The image recording apparatus according to Embodiment 1, wherein the back electrode has a substantially drum-shaped surface.

[Embodiment 5] The image recording apparatus according to Embodiment 1, wherein the back electrode is provided with a flexible belt.

[Embodiment 6] A toner source for supplying electrostatically charged toner particles, a particle flow modulation electrode member having a surface and an opening in the surface, and a surface of the modulation electrode member are provided in a facing relationship with each other, and Providing a back electrode remote from the toner source, applying a controlled electrical signal to the modulating electrode member and the back electrode to cause a flow of the charged toner particles through a predetermined one of the openings to the back electrode. A printing process comprising the steps of: flowing away, and heating the back electrode to a temperature high enough to melt the charged toner particles.

[0038]

As described above, by using the present invention, it is possible to provide a compact electrostatic printing apparatus with improved size and complexity.

[Brief description of drawings]

FIG. 1 is a side view of a partial schematic view of a preferred embodiment of the present invention.

FIG. 2 is a side view of a partial schematic view of an alternative embodiment of the present invention.

[Explanation of symbols]

 103: toner roller 113: opening 120: particle flow modulation electrode member 121: insulating layer 122: reference electrode layer 123: control electrode 130: back electrode 140: pressure member 150: thin film resistor 203: toner roller 213: opening 220 : Particle flow modulation electrode member 221: Insulating layer 222: Reference electrode layer 223: Control electrode 230: Back electrode 240: Pressure member 250: Thin film resistor

Claims (1)

[Claims] 1. A toner source for supplying electrostatically charged toner particles, a particle flow modulation electrode member having an opening having a plurality of openings, and a modulation electrode member remote from the toner source. A back electrode disposed in a facing relationship, and a control circuit that applies a controlled electric signal to the modulation electrode member and the back electrode to cause the flow of the charged toner particles to flow toward the back electrode through the opening. , The recording medium placed close to the surface of the back electrode and facing each other and sandwiched between the back electrode and the pressure member is located between the pressure member and the surface of the back electrode at a surface position directly opposite to the recording medium. An image recording apparatus comprising: a pressure member adapted to be pushed.