JPH03168768A - Image forming apparatus - Google Patents

Abstract

PURPOSE: To prevent electricity from being leaked between a control electrode and the other member and to easily form a clear image by forming a toner passing means of one or plural electroconductive materials and forming the surface of the electroconductive material directly faced to a toner carrier or the surface thereof directly faced to a recording material of an insulating layer. CONSTITUTION: The toner passing means constituted so that a toner passing empty hole 3a corresponding to image information is formed by an energizing control action corresponds to the control electrode 3 but the means executing such an action by the combination of the plural electrodes is included. The electrode 3 is constituted of plural X axes X1, X2... extended in a longitudinal direction and the respective pairs of Y axes Ya1, Ya2... inclined by a prescribed angle with respect to an energizing wire and extended in parallel by narrow width. Then, they are interposed by an insulating thin-layered film from both front and back sides. Besides, a through-hole is made to pierce through a part interposed by the respective pairs of Y axes and X axes and used as the toner passing empty hole 3a. Thus, the electricity is prevented from being leaked between the electrode 3 and the other member or such possibility that the electricity is leaked is prevented from occurring. As the result, the clear image is easily formed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an image forming apparatus configured to be capable of directly attaching a toner image to plain paper or other recording material without using a photoreceptor drum or other latent image carrier. ."Prior art" Conventionally, an electrostatic latent image, which is carried on a photoreceptor drum or other latent image carrier using modulated light in a dot pattern corresponding to a document image or image information, is developed using a developing device. An electrophotographic apparatus is known in which the visualized toner image is transferred onto plain paper after being visualized using a toner image, and is widely used in printers, copying machines, and other image forming apparatuses. Since an electrophotographic apparatus basically transfers a toner image onto a recording material via a latent image forming means, in addition to a means for converting image information into optical information, a latent image carrier, a transfer means, etc., the latent image is This requires a means for removing residual toner adhering to the image carrier, a means for removing toner written on the latent image carrier, and a means for recharging the latent image carrier, which not only makes the device configuration extremely complicated, but also requires The means must be placed around the photosensitive drum that functions as a latent image carrier, which results in an increase in the size of the device.In order to eliminate this drawback, electrostatic recording paper is used and needles arranged in a row are used. After making the recording paper carry an electrostatic latent image by bringing an electrode into direct contact with the recording paper and selectively applying a high voltage to the needle electrode, a toner image is attached to the recording paper using a developing device. A control electrode having a large number of micropores in the main scanning direction is arranged between the electrostatic recording device that visualizes the corona discharge in the air, and the electrostatic recording paper and the source that causes corona discharge in the air.
There is also an ion flow type electrostatic recording device configured to form a latent image on the electrostatic recording paper while controlling the flow of ions from the source using the control electrode. However, all of these methods require the use of electrostatic recording paper, which not only limits their versatility, but also forms the electrostatic latent image in the same way as the electrophotographic method described above. Since the process must be configured separately, there is a limit to miniaturization of the equipment. For this reason, various devices have been developed that use plain paper and can directly form a toner image on the recording material without forming a latent image. For example, in Japanese Patent Publication No. 60-45430, a screen-like member having a plurality of through-holes arranged in a matrix, each of which can be controlled with electricity, is disposed against the conductive ink liquid surface, and between the control electrode and the conductive liquid surface. After selectively applying a voltage according to an information signal to selectively introduce the conductive ink into the corresponding through-hole, the screen-like member is brought into contact with the surface of the recording material to perform image transfer. Image forming apparatuses have been proposed, but such apparatuses not only require an ink carrying step on a screen member and an image transfer step, but also have a structure that uses liquid ink, making it difficult to form clear images with minute dots. It is possible. Furthermore, as a method using so-called dry toner, for example, Japanese Utility Model Publication No. 7208/1983 discloses a toner container that supplies toner to a screen (to be described later), and a screen that is a first electrode in which a desired print pattern is formed by a number of holes. An apparatus has also been proposed that has a second electrode placed opposite to the second electrode and forms an image by inserting a recording material while applying a DC high voltage between the two electrodes. Since these systems use a screen on which a desired print pattern has been formed in advance, the image patterns that can be formed are subject to significant restrictions, and it is generally impossible to form images of anything other than numbers or alphabets. For this reason, it has been desired for many years to develop an apparatus that can eliminate all the drawbacks of the above-mentioned image forming apparatuses, but recently, Swedish Patent Application No. 8704883 (publication date June 9, 1989) has been proposed to achieve the above purpose. A matching image form or device is proposed. (hereinafter referred to as basic technology). FIG. 6 is a basic configuration diagram of this basic technology, in which a matrix is formed between a sleeve-shaped toner carrier 1 that electromagnetically holds toner in a thin film, and a back electrode 2 disposed opposite to the toner carrier 1. A control electrode 3 of the shape is arranged, and the control electrode 3 is
By controlling energization in the axial direction, the developing electric field acting on the holes 3a between the matrices can be selectively interrupted or conducted in accordance with image information, thereby making it possible to selectively cut off or conduct the developing electric field acting on the voids 3a between the matrices. Toner corresponding to the image information can be transferred from the toner carrier l onto the paper 4 through the holes 3a in the control electrode 3. Further, in this invention, the recording paper 4 is configured to be movable in a direction perpendicular to the axial direction of the sleeve forming the toner carrier 1, in other words, by utilizing both the electrodes and the toner carrier 1. It is possible to form a wide-area image of a predetermined area by combining strip-shaped images formed in one or more rows in the main scanning direction and a recording material conveyed in the sub-scanning direction. "Technical problem to be solved by the invention" However, although the above basic technology is theoretically excellent, there are various problems in putting it into practical use.The first of these is the problem of the control electrode. In other words, this basic technology uses a narrow gap (
In order to eliminate the gap between the control electrode 3 and the recording paper 4 (for example, several hundred μm), in addition to the thickness of the control electrode 3, the toner layer 1a supported on the toner carrier 1 is added to the narrow gap.
As a result, the gaps between the control electrode 3 and the toner layer la and between the control electrode 3 and the recording paper 4 become minute gaps of about 100 μm, respectively.
Moreover, within such a microgap, a toner carrier 1 and a back electrode 2 are placed.
Since a developing voltage is applied to the side and a control voltage for controlling the developing electric field is applied to the control electrode 3, if the withstand voltage decreases due to high humidity, or if the humidity recording paper is erroneously controlled. If the control electrode comes into contact with the control electrode, electric current or leakage may occur between the control electrode and other members, making image formation impossible. Furthermore, if the distance between the respective members, especially the gap between the control electrode 3 and the recording paper 4 changes, the dot diameter of the toner carried on the recording paper 4 through the holes 3a will change as a result. As a result, clear images cannot be formed. For this reason, it is necessary to accurately set the interval, but since the paper itself may be lifted up or wobble, and the toner image carried on the recording paper 4 is still in an unfixed state, the interval setting means If you try to set the interval by touching the recording paper, the image will be distorted. Furthermore, even if an attempt is made to set the spacing at the end of the shaft perpendicular to the recording paper transport direction in order to eliminate this drawback, if the paper size is large, lifting or the like will occur in the center, making it impossible to set the spacing uniformly. In view of the shortcomings of such basic technology, the present invention prevents the occurrence of electrical leakage or leakage between the control electrode and other members,
The purpose of this is to provide an image forming device that facilitates the formation of clear images. Another object of the present invention is to provide an image forming device that can accurately set gaps without causing any lifting or wobbling of the paper itself and without causing image disturbance. Another object of the present invention is to provide an image forming apparatus that can electrically correct any variation in the gap and prevent variation in the dot diameter of toner carried on recording paper. ``Technical Means for Solving the Problems'' Next, the invention that can achieve the above object will be explained step by step according to the claims. The toner passing means j forming 3a generally corresponds to the control electrode 3, but is not necessarily limited to the control electrode 3, and includes, for example, a combination of a plurality of electrodes that performs the above action. (Hereinafter, the passage means will be explained using the term control electrode 3 as an example.) Furthermore, the recording material described in the claims is not necessarily limited to only the recording paper 4, but also includes resin films, etc. will also be explained using the word recording paper 4 as an example. A. First, the invention described in claim 1 is such that the toner passing means is formed of one or more conductive materials to maintain the function as a control electrode, and at least the toner passing means directly facing the toner carrier is formed of one or more conductive materials. The feature is that the surface of the conductive material or the surface of the conductive material directly facing the recording material is formed with an insulating layer. As a result, even when the gaps between the control electrode 3 and the toner layer la and between the control electrode 3 and the recording paper 4 are set to minute gaps, the risk of electrical leakage or current leakage occurring between the control electrode and other members is completely eliminated. This makes it easier to form clear images. Note that when a conductive toner is used as the toner, it is necessary to cover the entire periphery of the conductive material with an insulating layer, but when an insulating toner is used, there is no need to take this into consideration. B. Next, the invention described in claim 2 proposes an image forming apparatus that can accurately set the gap without causing any lifting or wobbling of the paper itself and without causing image disturbance, In order to achieve this purpose, a slit opening having an opening width smaller than the gap between the control electrode and the back electrode, more preferably slightly larger than the recording paper, is set on the recording material entrance side, and the slit opening is The slit opening is located at least closer to the back electrode than the toner passing means, and more preferably, the slit opening is set on substantially the same plane as the back electrode. According to this technical means, in order for the recording paper to enter the image forming position in a state where lifting of the recording paper is forcibly suppressed in the width direction by the slit opening, the recording paper is moved at both ends in the axial direction. Even if it is inserted while being guided by the non-image forming part, it is easy to prevent the center from lifting up or wobbling. Furthermore, since the slit opening is set on the passer side of the recording paper before image generation, there is no possibility that the image will be disturbed even if the slit opening and the recording paper come into contact. Moreover, since the slit opening is formed along the back electrode, the above effect is further enhanced. C. Now, even if the above-mentioned gap setting is performed mechanically and accurately, since the gap is small, the relative fluctuation rate will be large due to manufacturing variations and other factors, and the dot diameter of the toner carried on the recording paper will still vary. Fluctuations will occur. Therefore, the invention as set forth in claim 4 controls the energization of the toner passing means using a pulse voltage, and adjusts the duty ratio and pulse width of the pulse voltage in response to changes in the distance between the toner passing means and other members. The key point is that other electrical input conditions are configured to be changeable. As a result, even if there is a fluctuation in the gap, it can be electrically corrected, and fluctuations in the dot diameter of the toner carried on the recording paper can be prevented. Moreover, the above correction can be performed with high precision. ``Example'' Hereinafter, an example of the present invention will be described in detail based on the drawings. However, unless otherwise specified, the dimensions, materials, shapes, and relative positions of the components described in this example are not intended to limit the scope of this invention, but are merely illustrative examples. Not too much. FIG. 2 is an overall configuration diagram showing an image forming apparatus according to an embodiment of the present invention, in which a paper feeding means consisting of a vapor cassette 15 and a paper feeding roller 16, a registration roller 17, and an insertion guide 6 are arranged along the conveyance path of the recording paper 4. , the image generation unit IO, and the transport plate 7, which are detailed in FIG.
, and a pair of fixing rollers l8, the recording paper 4 is fed from the paper cassette l5 by the paper feed roller 16.
waits at the entrance end of the registration roller 17, and then moves to the conveyance guide 6, timing the energization control timing of the control electrode 3.
The image is sent to the image generation unit IO via the . The conveyance guide 6 is formed of a grounded conductive member, and is formed so that it can be inserted into the image generation unit 10 after removing the electric charge by rubbing against the registration rollers 17, etc., and the guide 6 is slightly The recording paper 4 is curved upward in an R shape, so that the recording paper 4 is smoothly pushed along the surface of the back electrode 2 in the image generating section 10 while its leading end contacts the surface of the back electrode 2, as shown in FIG. It will be passed. Then, in the image generating section 1O, the recording paper 4 carrying an unfixed toner image corresponding to the image information is inserted into the fixing roller pair 18 via the conveying plate 7, and the image is fixed. The conveyance plate 7 is formed of a grounded flat conductive member like the conveyance guide 6, and is configured so that it can be inserted into the fixing roller pair after removing the electric charge accumulated in the image generation section IO. There is. The image generating section 10 is configured to be able to be divided into a first main body 10A and a second main body 10B, and the first main body 10A has a recording paper 4.
A strip-shaped opening 21 is provided on the lower surface side along the direction perpendicular to the conveyance direction.
a toner container 8 formed with a toner container 8, a toner conveying roller (toner carrier 1) disposed inside the toner container 8 facing the band-shaped opening 2l, and a control roller stretched substantially flush with the bottom surface of the toner container 8. These electrodes 3 are integrated into a unit, and the unit body is configured to be able to be extracted in the direction of coming into contact with and separating from a back electrode 2, which will be described later.
The second main body 10B includes a back electrode 2 fixed to a support member 31 and facing the control electrode 3 through a slit gap 11, and a support 30 that holds the back electrode 2 in position via an elastic member. The support body 30 forms a part of the main body of the device. Next, to explain each of these materials in detail, the toner container 8
A one-component magnetic toner is stored therein, and a doctor blade 22 is provided on the inner wall surface facing the conveyance roller. Further, on the bottom of the container, on the entry side in the conveying direction of the recording paper 4,
Adjacent to the band-shaped opening 2l, a thin knife-edge shaped smoother 23 is fixedly installed over almost the maximum width of the recording paper 4, and the guide of the recording paper 4 is controlled by the smoother 23. Furthermore, the bottom corner of the spacer 23 on the upstream side is rounded.
A wedge-shaped guide space is formed between the transport guide 6 and the transport guide 6, which gradually becomes narrower as it advances in the entry direction. The toner conveying roller l is composed of a developing sleeve 1a and a fixed magnet assembly (not shown) housed within the sleeve, and utilizes the magnetic holding force of the fixed magnet assembly to transfer the toner charged by frictional electrification between the toner particles. After the sleeve is rotated in the direction of the arrow, the layer thickness is regulated using the doctor blade 22, and the one layer of toner whose thickness has been regulated is conveyed to the band-shaped opening 21 position. Become. Further, a bias power source 24 is applied to the conveying roller 1, so that a developing electric field is formed between it and a back electrode 2, which will be described later. The control electrode 3 is arranged in the longitudinal direction (X) as shown in FIG. 5(a).
Multiple X axes extending to ilX1, X2...
and a pair of Y axes l11Yal, Ya2, which are inclined at a predetermined angle with respect to the current-carrying wire and extend narrowly in parallel.
These are sandwiched by insulating thin film, such as FPC, from both the front and back sides, and through holes are bored in the portions sandwiched between the Y-axis and the X-axis of each pair to form toner passage holes 3a. ．． As a result, by sequentially energizing the XI, x2 lines, etc. with a time difference as shown in FIG. As a result, the toner pattern becomes one row, and as a result, it is possible to form a dense dot pattern without making the Y-axis line width particularly dense. The control electrode 3 is stretched across the band-shaped opening 2l in a planar manner. Further, an energization control circuit 38 is connected to the control electrode 3, which generates a pulse signal (voltage) corresponding to image information via a duty ratio modulation circuit 37, and is capable of selectively controlling energization of the X-axis line and the Y-axis line. ing. As a result, the energization control circuit 3
Each decoder 3 based on the pulse signal generated by 8
9, as shown in FIG. 5(b), the X-axis and Y
By selectively controlling the energization of the axis, it is possible to selectively cut off or conduct the developing electric field acting on the holes 3a in accordance with image information, and thereby the back electrode 2
It becomes possible to supply toner corresponding to image information from the toner transport roller 1 side through the holes 3a in the control electrode 3 onto the recording paper 4 that is inserted through the surface. Further, the pulse signal is adjusted by the duty ratio modulation circuit 37 to correspond to the thickness of the control electrode 3 and the back electrode 2 or the recording paper, so that when a gap variation occurs between the control electrode 3 and the recording paper 4, it is adjusted to correspond to this. By changing the duty ratio and pulse width of the pulse signal, it is possible to adjust the developing electric field passing through the holes 3a, and as a result, it is possible to prevent variations in the dot diameter of the toner carried on the recording paper. The back electrode 2 has a main body 2a formed of a conductive member in the form of a strip and a flat plate so as to be able to face the control electrode 3 through a parallel slit gap, and the main body 2a is also formed of an insulating member extending in the longitudinal direction. 2b on the support member 2b so that it is almost flush with the support member 2b. A slit opening l2 having an opening width smaller than the gap between the control electrode and the back electrode, more preferably slightly larger than the recording paper, is formed between the spacer 23 and substantially on the same plane as the back electrode. On the other hand, the support body 30 forms a rectangular recessed space 32 in which the back electrode 2 is vertically displaceable, and an upper end of the recessed space 32 on the entrance side is formed in a key shape, so that the back electrode 2 The structure is such that the position can be regulated and locked. As shown in FIG. 3, the position of the back electrode 2 is regulated by insulating position regulating members provided on the bottom surface of the toner container 8 located at both ends in the longitudinal direction, so that the distance between the back electrode 2 and the control electrode 3 is regulated. In addition to configuring the settings to be accurate,
The recording paper guide section 5 is extended toward the center to the non-printing position of the control electrode 3. That is, as shown in FIG. 4, the guide part 5 has a downwardly arcuate shape, and the lower surface thereof is coated with a resin or the like having low sliding resistance, and the recording paper 4 can be inserted between it and the back electrode 2. They face each other through a microscopic gap. According to this embodiment, the image generating section 10 is
The recording paper 4 inserted into the slit opening 12 is guided along the spacer 23 on the entry side of the slit gap l1.
It is inserted into the slit cavity with high precision while forcing the material to rise or curve. At this time, since the spacer 23, which functions as a guide surface, is placed closer to the back electrode 2 side than the control electrode 3, the recording paper 4 inserted into the slit gap 11 may accidentally come into contact with the control electrode 3 side. There is no. The recording paper 4 inserted into the slit gap 11 is pushed through the surface of the back electrode 2 while being held by the recording paper guide section 5, but the back electrode 2 is configured to be displaceable by an elastic member 34. Therefore, even if the thickness of the recording paper changes, the gap between the control electrode 3 and the recording paper 4 can be maintained by the position regulating member 36, which is integrated with the recording paper guide section 5 provided at the end of the longitudinal axis. The position regulating member 3 is maintained constant.
The recording paper 4 is guided by the recording paper guide section 5 integrally formed with the recording paper 4
Since the structure allows the surface of the back electrode 2 to be inserted while maintaining the thickness of the recording paper 4, even if the paper thickness of the recording paper 4 fluctuates, this is absorbed by the vertical positional displacement of the back electrode 2, and as a result, the recording The paper 4 can be inserted stably without any lifting or the like, and even if the thickness of the recording paper 4 varies, it is possible to maintain a constant gap between the control electrode 3 and the recording paper 4. ．． In the above embodiment, the toner carrier was explained as a rotatable conveyance roller containing a fixed magnet assembly, but the magnet may be rotated without being fixed, and the outer developing sleeve may be fixed. , both magnets may be rotated in opposite directions. ``Effects'' As described above, according to the present invention, all the problems surrounding the control electrode in the basic technology described above are solved, and sharp long forming becomes possible. In particular, according to the invention set forth in claim 2, it is possible to prevent the occurrence of electrical leakage or leakage between the control electrode and other members, and according to the invention set forth in claims 2 and 3, It is possible to accurately set the gap without causing any lifting or wobbling of the paper itself, and without causing disturbance of the image, and furthermore, according to the invention set forth in claim 4, even if the gap changes, it is possible to set the gap by electricity. The diameter of the toner dots carried on the recording paper can always be maintained constant. It has various effects such as.

[Brief explanation of the drawing]

1 to 5 show an image forming apparatus according to an embodiment of the present invention, FIG. 2 is an overall configuration diagram, FIG. A cross-sectional view of the shaft end side, FIG. 4 is a cross-sectional view taken along the line A-A in FIG. 3, FIG. 5 (a) is a front view of the main part showing the control electrode, and FIG. FIG. 6 and FIG. 7 are a schematic configuration diagram showing the basic invention to which the present invention is applied, and an action diagram showing the energization control state thereof. Figure 8 is a schematic diagram.

Claims (1)

[Scope of Claims] 1) A toner carrier and a back electrode are disposed across a toner passing means that forms toner passing holes corresponding to image information by energization control, and a recording material is placed along the surface of the back electrode. In the image forming apparatus configured to be able to transfer the toner that has passed through the holes onto the recording material while moving the toner, the toner passing means is formed of one or more conductive materials, and at least directly faces the toner carrier. An image forming apparatus characterized in that an insulating layer is formed on the surface of the conductive material or the surface of the conductive material on the side directly facing the recording material 2) Forming toner passage holes corresponding to image information by controlling current flow. A toner carrier and a back electrode are arranged with a toner passing means therebetween, and the toner passing through the holes is transferred onto the recording material while the recording material is moved along the surface of the back electrode. In the forming apparatus, a slit opening smaller than the gap between the toner passing means and the back electrode is set on the recording material entrance side, and the slit opening is set at least closer to the back electrode side than the toner passing means. 3) The slit opening is set on substantially the same plane as the back electrode, and the non-image forming portions on both ends of the passing means in a direction substantially perpendicular to the direction of movement of the recording material are 4) The image forming apparatus according to claim 2, wherein a guide surface for moving the recording material is formed close to the back electrode side. In the image forming apparatus, the toner passing means is arranged such that the toner passing through the holes can be transferred onto the recording material while the recording material is moved along the surface of the back electrode. The energization control is performed using a pulse voltage, and the duty ratio, pulse width, and other electrical input conditions of the pulse voltage can be changed in response to changes in the distance between the passing means and other members. image forming device