JP2007003880A - Image forming apparatus and method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To accurately transfer a toner image from a photoreceptor to a base plate by preventing electricity from being discharged in a gap between the photoreceptor and the base plate when transferring the toner image from the photoreceptor to the base plate. <P>SOLUTION: In the image forming apparatus 1, transfer potential is imparted to the most proximate position to a transfer position on the surface of a semiconductive supporting belt 21 supporting the glass base plate 9 on an opposite side to the glass base plate 9, and auxiliary potential nearer to the surface potential of the photoreceptor 312 than the transfer potential is imparted to a position distant from the above-mentioned position by a predetermined distance in a direction Y parallel with the advancing direction of the glass base plate 9. Thus, the potential having distribution that a difference from the surface potential of the photoreceptor 312 is gradually decreased according as it separates from the transfer position in the direction Y is given to the glass base plate 9 through the supporting belt 21. As a result, the electricity is prevented from being discharged in the gap between the photoreceptor 312 and the glass base plate 9 near the transfer position, and the toner image is accurately transferred to the glass base plate 9. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a technique for forming a toner image or an electrostatic latent image on a substrate.

  An electrostatic latent image is formed by irradiating a photosensitive drum having a charged photoconductor with image forming light, and toner is applied to the electrostatic latent image to make it appear as a toner image, which is then transferred to printing paper. Thus, an electrophotographic printing apparatus that forms a toner image on a printing paper has been conventionally used. When a toner image is transferred to a printing paper in such a printing apparatus, a potential is applied to the opposite side of the printing paper from the photosensitive drum while the printing paper is brought into contact with the outer peripheral surface of the photosensitive drum at a predetermined transfer position. Thus, by forming an electric field, a so-called electric field transfer method is used in which toner, which is charged particles (or particles charged in a liquid), is moved from the photoreceptor to the printing paper.

  By the way, depending on the potential applied to the printing paper during the transfer of the toner image, the electric field locally increases in the gap between the photosensitive drum and the printing paper in the vicinity of the transfer position. Is known to be disturbed. Thus, for example, in Non-Patent Documents 1 and 2, an AC corona discharger is provided downstream of the transfer position on the side opposite to the photosensitive drum of the printing paper, and applied to the printing paper from another DC corona discharger during transfer. There has been disclosed a technique for suppressing the occurrence of electric discharge in the gap between the photosensitive drum and the printing paper immediately after separation from the photosensitive drum by rapidly removing the electric charges on the downstream side. In addition, the printing paper is curved with a small curvature near the transfer position and moved along the surface thereof, so that the distance between the photosensitive drum and the printing paper increases along the tangential direction of the photosensitive drum at the transfer position. There is also known a technique for suppressing the occurrence of discharge by abruptly increasing the width of the gap therebetween.

In addition to the electrophotographic method, a method of forming an electrostatic latent image on a drum having a dielectric layer using a multi-stylus that is a set of a plurality of pin electrodes is also known.
Electrophotographic Society, “Basics and Applications of Electrophotographic Technology”, Corona, 1988, p. 186-189 Hiroshi Takahara, “Recent Optimal Design and Application Development of Electrophotographic Process Technology and Equipment”, Management Development Center, June 30, 1989, p. 665

  By the way, in recent years, development of a technique for transferring a toner image from a photosensitive drum to a glass substrate having an insulating property and thicker than printing paper has been advanced. When a predetermined transfer potential is applied, the actual potential of the transfer surface at the transfer position of the object to which the image is transferred depends on the capacitance (capacitance) of the object. In order to perform this, it is necessary to apply a large transfer potential. However, when a large transfer potential is applied, an electric field is locally increased in the gap between the photosensitive drum and the glass substrate in the vicinity of the transfer position, and electric discharge is likely to occur. In the methods of Non-Patent Documents 1 and 2, since a high-voltage alternating current is used in the AC corona discharger, there is a problem that noise easily occurs in the printing apparatus. Since the glass substrate cannot be curved along the surface to be transferred, the above-described method of moving the object with a small curvature near the transfer position cannot be used.

  In addition, a flat belt-like annular member having a large capacitance is provided as an intermediate transfer member, and a toner image on the photosensitive member, which is another annular member provided along the outer periphery of the photosensitive drum, is subjected to intermediate transfer at a relatively low transfer voltage. It is conceivable to transfer it to the body once, and then transfer it from the intermediate transfer body to the glass substrate. However, in this case as well, when transferring to the glass substrate, a relatively large transfer potential is required and discharge occurs. It becomes easy.

  The present invention has been made in view of the above problems, and when transferring an image onto a substrate from an annular member on which an image is formed on the outer peripheral surface as a toner image or an electrostatic latent image, the annular member and the substrate are located in the vicinity of the transfer position. The purpose of this is to prevent discharge from occurring in the gap between and an image from the annular member onto the substrate with high accuracy.

  The invention according to claim 1 is an image forming apparatus for forming a toner image or an electrostatic latent image on a substrate, and an original image which is a toner image or an electrostatic latent image before transfer is formed on an outer peripheral surface. An original image holding unit that circulates and moves a cylindrical drum-like or flat belt-like annular member along the outer peripheral surface, and the substrate to be transferred while bringing the transfer surface of the substrate closest to the outer peripheral surface at a predetermined transfer position. A moving mechanism that moves in the same direction as the portion of the annular member at the same speed as the portion of the annular member at the transfer position and in a traveling direction along the transfer surface, and an original image on the outer peripheral surface. When transferring onto the substrate at the transfer position, the difference from the surface potential of the annular member gradually decreases with distance from the transfer position in one direction which is the traveling direction or the direction opposite to the traveling direction. distribution The said transferred surface of the substrate potential with and a transfer section that gives on the opposite side.

  A second aspect of the present invention is the image forming apparatus according to the first aspect, further comprising a support member having a contact surface that contacts a surface opposite to the transfer surface of the substrate in the vicinity of the transfer position. And the transfer section generates a potential having the distribution on the contact surface of the support member.

  A third aspect of the present invention is the image forming apparatus according to the second aspect, wherein the support member is formed of a semiconductive material having a constant thickness, and the transfer portion is formed of the support member. A first potential applying unit configured to apply a first potential to a position closest to the transfer position with the support member and the substrate interposed on a surface opposite to the contact surface; and the first potential By applying a second potential closer to the surface potential of the annular member than the first potential to the support member at a position away from the applying portion in the one direction by a predetermined distance, A second potential applying unit that generates a potential having the distribution on the support member.

  According to a fourth aspect of the present invention, in the image forming apparatus according to the third aspect, at least one of the first potential applying unit and the second potential applying unit is the first potential or the second potential. And a roller that contacts the surface of the support member opposite to the contact surface. The roller is formed by covering the periphery of the electrode to which the potential is applied with a conductive elastic material.

  A fifth aspect of the present invention is the image forming apparatus according to the third aspect, wherein the first potential applying unit is a corona discharger.

  A sixth aspect of the present invention is the image forming apparatus according to the third aspect, wherein the second potential applying portion is formed of a conductive material, and the contact surface of the support member is A brush that contacts the opposite surface is provided.

  According to a seventh aspect of the present invention, in the image forming apparatus according to the first aspect, the distribution of the potential that the transfer unit applies to the surface of the substrate opposite to the surface to be transferred is It further has a distribution in which the difference from the surface potential of the annular member gradually decreases as the position moves away from the transfer position in a direction opposite to the direction.

  The invention according to claim 8 is the image forming apparatus according to claim 7, further comprising a support member having an abutting surface that abuts a surface opposite to the surface to be transferred of the substrate in the vicinity of the transfer position. And the transfer section generates a potential having the distribution on the contact surface of the support member.

  The invention according to claim 9 is the image forming apparatus according to claim 8, wherein the support member is formed of a semiconductive material having a constant thickness, and the transfer portion is formed of the support member. A first potential applying unit configured to apply a first potential to a position closest to the transfer position with the support member and the substrate interposed on a surface opposite to the contact surface; and the first potential The surface potential of the annular member is made higher than the first potential on the support member at a position away from the applying portion by a predetermined distance in the one direction and the direction opposite to the one direction. Two second potential applying portions that generate a potential having the distribution on the support member by applying a close second potential.

  A tenth aspect of the present invention is the image forming apparatus according to any one of the third to sixth and ninth aspects, wherein the second potential has a polarity opposite to the first potential. Or it is a ground potential.

  The invention according to claim 11 is the image forming apparatus according to any one of claims 1 to 10, wherein the original image is formed by applying liquid toner to the electrostatic latent image on the outer peripheral surface. It is a toner image.

  According to a twelfth aspect of the present invention, there is provided an image forming method for forming a toner image or an electrostatic latent image on a substrate, wherein a toner image before transfer or an original image which is an electrostatic latent image is formed on an outer peripheral surface. A circular movement step of circulating and moving a cylindrical drum-like or flat belt-like annular member along the outer peripheral surface, and a transfer surface of the substrate at the predetermined transfer position on the outer peripheral surface in parallel with the circular movement step. Moving the substrate in the same direction as the part of the annular member at the same speed as the part of the annular member at the transfer position and moving in the advancing direction along the transferred surface, A transfer step of transferring the original image on the outer peripheral surface onto the substrate at the transfer position in parallel with the movement step, and in the transfer step, the advancing direction or a direction opposite to the advancing direction. one Potential having a difference gradually decreases the distribution of the surface potential of the annular member moves away from said transfer position in the direction is given to the surface opposite to the transferred surface of the substrate.

  According to the present invention, a potential having a distribution in which the difference from the surface potential of the annular member gradually decreases as the distance from the transfer position in one direction decreases, thereby causing the annular member and the substrate to move in the vicinity of the transfer position. It is possible to prevent discharge (including suppression) from occurring between the gaps, and to accurately transfer the original image from the annular member onto the substrate.

  In the inventions of claims 3 and 9, a potential having a distribution can be easily applied to the substrate. In the invention of claim 4, the potential from the first potential applying unit or the second potential applying unit including the roller is applied. It can be appropriately applied to the support member.

  In the invention of claim 5, the first potential can be applied to the support member in a non-contact manner, and in the invention of claim 6, the configuration of the second potential applying section can be simplified.

  According to the seventh aspect of the present invention, a potential having a distribution in which the difference from the surface potential of the annular member gradually decreases toward the one direction and the direction opposite to the one direction as it moves away from the transfer position is applied to the substrate. Accordingly, the original image can be transferred from the annular member onto the substrate with higher accuracy. According to the invention of claim 10, it is further prevented that discharge is generated in the gap between the annular member and the substrate in the vicinity of the transfer position. can do.

  FIG. 1 is a diagram showing a configuration of an image forming apparatus 1 according to an embodiment of the present invention. The image forming apparatus 1 in the present embodiment is a printing apparatus that forms an image of toner on a glass substrate using electrophotography, and the toner image is fixed on the glass substrate via a fixing device (not shown) downstream. As a result, a color filter for a flat display device such as a liquid crystal display device is manufactured. Actually, three image forming apparatuses 1 and fixing apparatuses respectively corresponding to three color toners of R (red), G (green), and B (blue) are provided in a row.

  The image forming apparatus 1 shown in FIG. 1 is provided with an annular support belt 21 formed of a semiconductive material having a constant thickness, and each of them is arranged side by side while extending in the X direction and separating in the Y direction in FIG. Two rollers 221a and 221b are provided, and the support belt 21 is hung on the two rollers 221a and 221b. A motor 222 is connected to one of the rollers 221a, and the support belt 21 is circulated through the two rollers 221a and 221b by driving the motor 222. For example, a glass substrate 9 having a thickness of 0.3 to 0.7 millimeters (mm) is placed on a portion of the support belt 21 above the rollers 221a and 221b (on the (+ Z) side). The glass substrate 9 has a lower surface (main surface on the (−Z) side) of the outer peripheral surface of the support belt 21 (exactly, an outer peripheral surface facing the (+ Z) direction at a position above the rollers 221a and 221b of the support belt 21. Hereinafter, the portion of the outer peripheral surface at the part is referred to as “contact surface”) and is moved horizontally in the Y direction by the circulating movement of the support belt 21 while being supported by contact. In the image forming apparatus 1, the substrate moving mechanism 22 that moves the glass substrate 9 on the support belt 21 is configured by the two rollers 221 a and 221 b and the motor 222.

  The image forming apparatus 1 includes a process unit 3 that faces a glass substrate 9 on a support belt 21 and forms a color toner image of R, G, or B color on a photosensitive drum by electrophotography, and a support belt 21 further includes a transfer unit 4 that applies a potential to a part on the process unit 3 side (that is, a part having a contact surface).

  The process unit 3 includes a photosensitive drum 31 having a diameter of 250 mm connected to a motor (not shown) via a speed reducer, and the photosensitive drum 31 is supported rotatably about a rotation axis J1 parallel to the X direction. The photosensitive drum 31 includes a drum body 311 that is formed of a metal such as aluminum and that has a rotation axis J1 as the center. The drum body 311 is electrically grounded. On the outer peripheral surface of the drum body 311, for example, a single layer type organic photoreceptor having a phthalocyanine pigment (hereinafter simply referred to as “photoreceptor 312”) is uniformly applied (or deposited). The diameter of the photosensitive drum 31 is not limited to 250 mm, but is preferably 200 mm or more and 400 mm or less. Further, the photoconductor 312 may be formed of an inorganic photoconductor such as amorphous silicon in addition to the single layer type organic photoconductor having a phthalocyanine pigment.

  The process unit 3 further includes a charger 32 provided to face the photosensitive drum 31, and the charger 32 generates ions to charge the photoreceptor 312. Further, the photosensitive drum 31 is formed on the photosensitive member 312 and a latent image forming portion 33 that emits image forming light clockwise from the charger 32 to form an electrostatic latent image on the photosensitive member 312. A developing unit 34 for developing the electrostatic latent image by applying a liquid toner (for example, a wet toner dispersed in an isoparaffin-based insulating solvent (carrier liquid)), and a cleaner 35 for cleaning the surface of the photoreceptor 312. In addition, a static eliminator 36 that emits light to neutralize the photoconductor 312 is disposed. The developing unit 34 is connected to a toner supply unit (not shown) that supplies liquid toner as a developing solution.

  The glass substrate 9 on the support belt 21 is closest to the outer peripheral surface of the photoconductor 312 between the developing unit 34 and the cleaner 35 on the moving path of the site of the photoconductor 312. As will be described later, the toner on the outer peripheral surface of the photoconductor 312 is transferred to the upper surface of the glass substrate 9 at a position where the photoconductor 312 and the glass substrate 9 are closest to each other. The position closest to the glass substrate 9 is called a transfer position, and the upper surface of the glass substrate 9 is called a transferred surface. The transfer position is a position fixed relative to the process unit 3.

  The transfer unit 4 has a predetermined transfer potential (for example, (+3000) V) with respect to the same position as the transfer position in the Y direction on the surface of the support belt 21 opposite to the contact surface on the process unit 3 side. And a transfer potential applying unit 41 for applying the transfer potential, and a predetermined position at a position away from the transfer potential applying position by the transfer potential applying unit 41 in the (+ Y) direction and the (−Y) direction by the same distance (for example, 4 cm). 2) (for example, (−1000) V, hereinafter referred to as “auxiliary potential”)).

  FIG. 2 is an enlarged view showing the vicinity of the transfer position. As shown in FIG. 2, the transfer potential applying section 41 is provided with a transfer potential from the transfer potential supplying section 414 and has an electrode 411 that is long in the X direction in FIG. 2, and the conductive rubber 412 is surrounded by the electrode 411. Thus, the transfer roller 413 is formed. On the surface opposite to the contact surface of the support belt 21, the transfer roller 413 contacts the position closest to the transfer position with the support belt 21 and the glass substrate 9 interposed between the transfer roller 413 and the photosensitive drum 31. Similarly to the transfer potential applying unit 41, each auxiliary potential applying unit 42 is provided with an auxiliary potential from the auxiliary potential supply unit 424 and has an electrode 421 that is long in the X direction, and the periphery of the electrode 421 is made of conductive rubber 422. Thus, a roller (hereinafter referred to as “auxiliary roller”) 423 is formed, and the auxiliary roller 423 is disposed on the surface opposite to the contact surface of the support belt 21 at a position away from the transfer roller 413 in the Y direction. Abut. In each of the transfer roller 413 and the two auxiliary rollers 423, the conductive rubbers 412 and 422 are elastically deformed in a state where the glass substrate 9 is placed on the support belt 21. A potential is uniformly applied to the support belt 21 in the direction along the transfer surface (X direction). The transfer roller 413 and the auxiliary roller 423 may be formed by covering the electrodes 411 and 421 with a conductive elastic material other than conductive rubber.

  FIG. 3 is a diagram illustrating a flow of processing in which the image forming apparatus 1 forms a toner image on the glass substrate 9. Note that steps S12 to S15 in FIG. 3 show the flow of processing focusing on a part of the photoconductor 312, and the entire photoconductor 312 is actually performed substantially in parallel in time.

  In the image forming apparatus 1 of FIG. 1, first, the photosensitive drum 31 starts rotating at a constant rotational speed about the rotation axis J1 in the clockwise direction (the rotation direction indicated by the arrow 71 in FIG. 1) and the glass substrate 9. Also starts moving in the (+ Y) direction at a constant speed (steps S11a and S11b). In the process unit 3, by the rotation of the photosensitive drum 31, a cylindrical drum-shaped photosensitive member 312 centering on the rotation axis J <b> 1 is arranged around each peripheral configuration (that is, the charger 32, the latent image forming unit 33, the developing unit). 34, the cleaner 35 and the static eliminator 36) are continuously circulated, and the processing on the photosensitive member 312 with these peripheral components is started. In the glass substrate 9 in the present embodiment, a lattice-like black matrix is formed in advance on another surface to be transferred (that is, the surface facing the process unit 3) by another apparatus.

  In the charger 32, charges are sequentially applied to a part of the photoconductor 312 (hereinafter referred to as “target part”) that reaches the facing position, and the surface of the target part is, for example, (−700) volts (V ) To uniformly charge (step S12). The charged target portion continuously moves to the light irradiation position of the latent image forming unit 33. The latent image forming unit 33 includes a light source in which a plurality of light emitting diodes (LEDs) that emit light having a predetermined wavelength are arranged (LED array). Of the image data of each color component generated from the image showing the color filter pattern, image data corresponding to the color of the toner of the process unit 3 is input to the latent image forming unit 33, and according to this image data Image forming light is emitted toward the photoreceptor 312. At the target portion of the photoconductor 312, the portion irradiated with light moves to the surface of the photoconductor 312 and is removed. In addition, since the charged state is maintained as it is in the portion that is not irradiated with light, an image (that is, an electrostatic latent image) is formed on the surface of the photoconductor 312 (ie, an electrostatic latent image) (step S13). The light source of the latent image forming unit 33 is not necessarily an LED, and may be, for example, a semiconductor laser or a combination of a lamp and a liquid crystal shutter.

  The portion (target portion) where the electrostatic latent image is formed on the photosensitive drum 31 moves to a position facing the developing portion 34, and is dispersed and charged in the liquid toner (solvent in the solvent) by the developing roller 341 of the developing portion 34. Toner) is applied to the electrostatic latent image (step S14). At this time, the toner charged to the same polarity as the surface of the photoconductor 312 adheres only to the portion of the target portion on the photoconductor 312 where the charge has been removed, and the electrostatic latent image is developed. That is, a toner image is formed on the target portion of the photoreceptor 312. It should be noted that the charged toner may adhere to a charged portion on the photoconductor 312.

  Thereafter, the target portion reaches a transfer position that is closest to the transfer surface of the glass substrate 9, and at the transfer position, the target portion is at a speed corresponding to the rotational speed of the photosensitive drum 31 (that is, rotation of the outer peripheral surface of the photosensitive drum 31). It moves accurately in the (+ Y) direction at a tangential speed in the cross section perpendicular to the axis J1. In addition, the glass substrate 9 on the support belt 21 is also moved along the transfer surface by the substrate moving mechanism 22 at the same speed as the target portion at the transfer position, with the same (+ Y) direction as the traveling direction of the target portion as the traveling direction. The transfer roller 413 in FIG. 2 slightly presses the glass substrate 9 toward the photosensitive drum 31 ((+ Z) side) via the support belt 21 at the transfer position. 9 is in contact with the surface to be transferred via the toner (not necessarily in contact; the same applies hereinafter).

  FIG. 4 is a diagram showing the potential acting on the support belt 21 in the vicinity of the transfer position. FIG. 4 shows only the potential generated in the support belt 21 between the position P1 in the Y direction where the transfer roller 413 contacts and the position P2 in the Y direction where the auxiliary roller 423 on the (−Y) side contacts.

  As described above, a positive transfer potential is applied to the support belt 21 by the transfer potential applying unit 41, and a negative auxiliary potential having a polarity opposite to the transfer potential is applied by the auxiliary potential applying unit 42. A constant current flows from the transfer roller 413 to the auxiliary roller 423 through the support belt 21 having a constant thickness and a semiconductive property. At this time, in the support belt 21, the difference (voltage) between the potential at the transfer position and the potential at a certain position away from the transfer position in the Y direction is the resistance of the portion from the transfer position of the support belt 21 to the position, and the support belt 21. This is the product of the current flowing through the belt 21, and the resistance of this portion is proportional to the distance in the Y direction from the transfer position to the position. Therefore, as shown in FIG. 4, the potential of each part of the support belt 21 is such that the transfer potential A1 is from the position P1 where the transfer roller 413 contacts in the Y direction toward the position P2 where the (−Y) side auxiliary roller 423 contacts. To the auxiliary potential A2 (that is, a potential gradient is formed in the support belt 21).

  Further, since the auxiliary potential A2 is closer to the surface potential A0 of the photoconductor 312 than the transfer potential A1, the difference (absolute value) from the surface potential of the photoconductor 312 as it moves away from the transfer position P1 in the (−Y) direction. Is generated on the contact surface of the support belt 21, and this distributed potential is applied to the glass substrate 9 to be covered (hereinafter referred to as “distribution potential”). It is given to the surface (lower surface) opposite to the transfer surface. In this embodiment, since the surface potential A0 of the photoconductor 312 is a value between the transfer potential A1 and the auxiliary potential A2, the surface potential of the photoconductor 312 from the transfer position P1 toward the (−Y) direction. The range of the distribution potential where the difference gradually decreases (hereinafter referred to as “potential difference decrease range”) is precisely from the transfer position P1 to the position P0 where the potential is A0. If the auxiliary potential is a value between the transfer potential and the surface potential of the photoreceptor 312, the potential difference reduction range is from the transfer position P1 to the position P2 where the (−Y) side auxiliary roller 423 contacts. Become.

  Due to the above distribution potential, the transfer surface of the glass substrate 9 has a potential opposite to that of the toner at the transfer position, and the toner on the target portion of the photoreceptor 312 moves to the transfer surface of the glass substrate 9. (Step S15). Further, within the potential difference decreasing range in the vicinity of the transfer position, the difference between the surface potential of the photoconductor 312 and the potential on the transfer surface of the glass substrate 9, that is, the outer peripheral surface of the photoconductor 312 and the transfer surface of the glass substrate 9. Since the voltage acting on the gap between the first and second gaps gradually decreases from the transfer position in the (−Y) direction, and the width of the gap also increases gradually, the voltage from the transfer position in the (−Y) direction. As the distance increases, the electric field in the gap rapidly decreases. In the image forming apparatus 1, the potential distribution is the same on the (+ Y) side of the transfer position, and the outer peripheral surface of the photoconductor 312 and the glass substrate 9 are near both the (+ Y) side and the (−Y) side of the transfer position. It is prevented (including suppression) that the electric field acting on the gap between the transfer surface and the surface to be transferred becomes equal to or higher than the breakdown electric field of the gap.

  The target portion continues to move to the position of the cleaner 35 in FIG. 1, and unnecessary materials such as toner remaining on the target portion of the photoreceptor 312 (that is, toner that has not been transferred to the glass substrate 9) are removed by the cleaner 35. Then, the surface of the photoconductor 312 is cleaned, and the photoconductor 312 is mechanically returned to the initial state. Then, light is irradiated by a combination of a lamp and a filter, or a static eliminator 36 having an LED or the like, so that the photosensitive member 312 is neutralized and is electrically returned to an initial state.

  The processes in steps S12 to S15 are performed almost in parallel on each part on the photoconductor 312, and the process is continuously performed on each part of the photoconductor 312 that sequentially reaches the transfer position. Eventually, the entire toner image on the outer peripheral surface of the photoreceptor 312 is transferred onto the transfer surface of the glass substrate 9 at the transfer position. When the printing on the entire glass substrate 9 is completed, the rotation of the photosensitive drum 31 is stopped, the substrate moving mechanism 22 is stopped, and the printing process by the image forming apparatus 1 is completed (steps S16a and S16b). As a result, a toner image of one color is formed on the entire transfer surface of the glass substrate 9.

  As described above, in practice, when three image forming apparatuses corresponding to the respective colors of R, G, and B are prepared and a toner image of one color is formed on the glass substrate 9, the glass substrate 9 is conveyed to the next image forming apparatus to form a toner image of the next color. As a result, toner images of R, G, and B colors are formed on the glass substrate 9 by the three image forming apparatuses, and finally, the toner images are heated and melted by the fixing device and fixed on the glass substrate 9. The color filter is completed.

  By the way, depending on the design and setting conditions of the image forming apparatus such as the distance in the Y direction between the transfer roller 413 and the auxiliary roller 423, or the magnitude of the transfer potential and the auxiliary potential, the outer peripheral surface of the photoreceptor 312 and the glass substrate. It is also conceivable that the electric field acting in the vicinity of the transfer position in the gap between the transfer surface 9 and the transfer surface 9 is greater than the breakdown electric field. Even when such design and setting conditions are unavoidable, the liquid toner carrier liquid is filled in the portion in the vicinity of the transfer position of the gap so that the outer peripheral surface of the photoconductor 312 It is possible to prevent electric discharge from occurring between the glass substrate 9 and the transfer surface (the same applies to the image forming apparatus shown in FIGS. 5 to 9 described later). From such a viewpoint, it can be said that the toner image formed by the image forming apparatus 1 is preferably formed by applying liquid toner to the electrostatic latent image on the outer peripheral surface of the photoreceptor 312. Of course, depending on the design and setting conditions of the image forming apparatus, powdered toner (that is, toner charged without being dispersed in the carrier liquid) may be used.

  As described above, in the image forming apparatus 1 in FIG. 1, the (+ Y) direction and the (−Y) direction when transferring the toner image on the photoconductor 312 to the transfer surface of the glass substrate 9 at the transfer position. A potential having a distribution in which the difference from the surface potential of the photosensitive member 312 gradually decreases as the distance from the transfer position is increased toward the glass substrate 9 by the transfer unit 4 via the support belt 21. As a result, in the vicinity of the transfer position, a discharge occurs between the photoconductor 312 and the glass substrate 9, and the toner image on the outer peripheral surface of the photoconductor 312 immediately before transfer, or the transfer surface of the glass substrate 9 immediately after transfer. The upper toner image can be prevented from being disturbed, and as a result, the toner image can be accurately transferred onto the glass substrate 9.

  Further, in the image forming apparatus 1, the auxiliary potential applied to the support belt 21 by the auxiliary potential applying unit 42 has a polarity opposite to the transfer potential applied by the transfer potential applying unit 41, so that the transfer potential and the auxiliary potential are supplemented. Compared to the case where the potential is the same polarity, a steep distribution potential is generated in the support belt 21, further preventing discharge from occurring in the gap between the photoreceptor 312 and the glass substrate 9 in the vicinity of the transfer position. can do.

  FIG. 5 is a diagram showing another example of the transfer portion. In the transfer unit 4a in FIG. 5, a transfer potential applying unit 41a having a DC corona discharger 415 is provided instead of the transfer potential applying unit 41 having the transfer roller 413 in FIG. A transfer potential supply unit 414 is connected to the discharge wire of the corona discharger 415.

  When the toner image on the outer peripheral surface of the photoreceptor 312 is transferred onto the glass substrate 9 at the transfer position, the support belt 21 is in contact with the photosensitive drum 31 on the surface opposite to the contact surface of the support belt 21. In addition, a charge (discharge ion) is applied from the corona discharger 415 to a position closest to the transfer position with the glass substrate 9 interposed therebetween, so that a transfer potential is applied to the position in a non-contact state with the support belt 21. The As a result, a potential having a distribution in which the difference from the surface potential of the photoconductor 312 gradually decreases with increasing distance from the transfer position in the (+ Y) direction and the (−Y) direction is generated in the support belt 21 and the glass substrate 9 is covered. It acts on the surface opposite to the transfer surface. As a result, electric discharge can be prevented from occurring in the gap between the photoconductor 312 and the glass substrate 9 in the vicinity of the transfer position, and the toner image can be accurately transferred onto the glass substrate 9.

  FIG. 6 is a diagram showing still another example of the transfer portion. In the transfer unit 4b of FIG. 6, an auxiliary potential applying unit 42a having a brush 425 formed of a conductive material is provided instead of each auxiliary potential applying unit 42 having the auxiliary roller 423 of FIG. An auxiliary potential supply unit 424 is connected to each brush 425, and the brush 425 is on the surface opposite to the contact surface of the support belt 21 from the transfer roller 413 by a predetermined distance in the (+ Y) direction or the (−Y) direction. Auxiliary potential is applied to these positions in contact with the distant positions. As described above, in the image forming apparatus of FIG. 6, the configuration of the auxiliary potential applying unit is simplified by using the brush 425 instead of the auxiliary roller 423, and the gap between the photoconductor 312 and the glass substrate 9 in the vicinity of the transfer position. Thus, the toner image can be transferred onto the glass substrate 9 with high accuracy.

  In addition, the transfer unit 4 in FIG. 1 has a transfer potential applying unit 41 and two auxiliary potential applying units 42, the transfer unit 4a in FIG. 5 has two auxiliary potential applying units 42, and the transfer unit 4b in FIG. Then, only the transfer potential applying unit 41 is provided with a transfer roller 413 or an auxiliary roller 423. As described above, in the above-described image forming apparatus, at least one of the transfer potential applying unit and the two auxiliary potential applying units is provided with a roller, and in the transfer potential applying unit 41 or the auxiliary potential applying unit 42 provided with the roller. It is realized that the roller is elastically deformed to stably and appropriately apply the potential to the support belt 21. In addition to the corona discharger and the brush described above, the potential applying portion where no roller is provided is formed of a metal or a semiconductive material within a range in which a potential can be appropriately applied to the support belt 21. A roller or a metal contact piece may be provided.

  FIG. 7 is a diagram illustrating a configuration of an image forming apparatus 1a according to another example. In the image forming apparatus 1 a of FIG. 7, an intermediate transfer unit 25 having an intermediate transfer body 251 is provided, and the toner image on the photosensitive drum 31 is indirectly transferred onto the glass substrate 9 via the intermediate transfer body 251. Specifically, the intermediate transfer member 251 is a flat belt-like annular member formed of a dielectric material, and is provided so as to circumscribe the two rollers 252a and 252b. A motor is connected to one of the rollers 252a, and when the motor is driven, the intermediate transfer member 251 circulates and moves along the outer peripheral surface while being in contact with the portion of the photosensitive drum 31 where the toner image is formed. A DC power supply 253 is connected to the other roller 252b. In the image forming apparatus 1a of FIG. 7, the toner image formed on the photoconductor 312 by the latent image forming unit 33, the developing unit 34, etc. is circulated on the intermediate transfer member 251 by the potential applied via the roller 252b. Is transcribed. The portion of the intermediate transfer body 251 on which the toner image is formed is sent to the glass substrate 9, and a voltage is generated between the intermediate transfer body 251 and the glass substrate 9 while preventing the transfer unit 4 from discharging near the transfer position. The applied toner image on the intermediate transfer body 251 is transferred onto the glass substrate 9.

  In the image forming apparatus 1a of FIG. 7, the glass substrate 9 moves in the (−Y) direction in FIG. 7 during image formation. Further, in the image forming apparatuses 1 and 1 a, the developing unit 34 is omitted, and the transfer unit 4 applies a transfer potential having a polarity opposite to the charge of the electrostatic latent image to the glass substrate 9, while the electrostatic potential on the photoreceptor 312 is applied. The latent image or the electrostatic latent image on the intermediate transfer member 251 transferred from the photosensitive member 312 may be transferred onto the glass substrate 9.

  As described above, in the image forming apparatus, the photosensitive drum 31 or the intermediate transfer unit 25 has a cylindrical drum shape on which an original image that is a toner image or an electrostatic latent image before transfer to the glass substrate 9 is formed on the outer peripheral surface. Alternatively, by performing an operation as an original image holding unit that circulates and moves a flat belt-shaped annular member along the outer peripheral surface, the original image to be transferred to the glass substrate 9 is sent to the transfer position and is transferred to the glass substrate 9. Transcribed above. A multi-stylus that is a set of a plurality of pin electrodes is provided as a latent image forming portion, and an annular member formed of a dielectric material is provided in the original image holding portion, and is opposed to the outer peripheral surface of the annular member through a gap. An electrostatic latent image may be formed by applying a voltage to the pin electrode to cause discharge between the tip of the pin electrode and the annular member, thereby applying an electric charge to the outer peripheral surface of the annular member.

  Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications can be made.

  In the above-described embodiment, a transfer potential and an auxiliary potential are applied to the semiconductive support belt 21, and the distribution potential having a distribution in which the difference from the surface potential of the photoreceptor 312 gradually decreases as the distance from the transfer position in the Y direction is increased. By causing the support belt 21 to generate the distribution potential, it is easy to apply the distributed potential to the surface of the glass substrate 9 opposite to the transfer surface. However, in the image recording apparatus, the contact surface of the support belt can be obtained by other methods. A distributed potential may be generated. For example, the image forming apparatus of FIG. 8 is formed of an insulating material having a constant thickness, and is provided with an annular support belt 21a having the same shape as the support belt 21 of FIG. A plurality of DC-type corona dischargers for applying a charge toward the support belt 21a are arranged side by side in the Y direction. A predetermined amount per unit time from each of the plurality of corona dischargers 43a on the (−Y) side of the transfer position with respect to the Y direction toward the surface opposite to the contact surface of the support belt 21a that circulates and moves. Positive charges, and the same amount of negative charge as that of the corona discharger 43a is applied per unit time from each of the (+ Y) side corona dischargers 43b from the transfer position. As a result, in the image forming apparatus of FIG. 8, the distribution potential at which the difference from the surface potential of the photoconductor 312 gradually decreases as the distance from the transfer position increases in the (+ Y) direction and (−Y) direction. And is given to the surface of the glass substrate 9 opposite to the surface to be transferred. The plurality of corona dischargers 43b on the (+ Y) side of the transfer position may be a plurality of ionizers, and the charge on the support belt 21a may be removed as the distance from the transfer position in the (+ Y) direction increases.

  As still another example of the method for generating the distributed potential on the contact surface of the support belt, the image forming apparatus shown in FIG. 9 is formed of a photoconductor, and the annular shape of the same shape of the support belt 21 of FIG. A support belt 21b is provided, and a DC-type corona discharger 44 that applies a charge to a position closest to the transfer position of the support belt 21b is disposed inside the support belt 21b. On the (+ Y) side of the corona discharger 44, there is a light irradiation unit 45 that irradiates light of uniform intensity over a certain range in the Y direction toward the surface opposite to the contact surface of the support belt 21b. The support belt 21 b is electrically grounded via the conductive roller 46 in the vicinity of the (+ Y) side of the region on the support belt 21 b that is provided and irradiated with light from the light irradiation unit 45. In each part of the support belt 21b, the amount of light (accumulated light amount) gradually increases as the support belt 21b moves away from the transfer position in the (+ Y) direction due to the circular movement of the support belt 21b. In the image forming apparatus of FIG. 9, the electric charge applied by the corona discharger 44 below the transfer position moves to the inside of the support belt 21b and is removed by irradiating the support belt 21b with light. At this time, the amount of electric charge moving inside the support belt 21b increases as the applied light amount increases away from the transfer position in the (+ Y) direction. Therefore, in the image forming apparatus, the transfer belt moves from the transfer position toward the (+ Y) direction. A distributed potential having a distribution in which the difference from the surface potential of the photoconductor 312 gradually decreases as the distance from the photosensitive member 312 increases, and is applied to the surface of the glass substrate 9 opposite to the surface to be transferred. Become. In the image forming apparatus of FIG. 9, in the gap between the photoconductor 312 and the glass substrate 9 on the (−Y) side of the transfer position, the liquid toner is filled with a carrier liquid as necessary and discharged. Is prevented.

  As described above, the transfer unit that applies the distributed potential to the glass substrate 9 in the image forming apparatus can be realized in various configurations. In the support belt 21 in the above embodiment, the abutment surface abuts on the surface of the glass substrate 9 opposite to the surface to be transferred, so that even the large glass substrate 9 is supported stably and appropriately. However, when the glass substrate 9 is supported by gripping the outer edge of the glass substrate or arranging a plurality of rollers each extending in the X direction in the Y direction, the glass substrate 9 A transfer portion that directly applies a distribution potential may be provided on the surface opposite to the surface to be transferred.

  In the above embodiment, an auxiliary potential having a polarity opposite to the transfer potential is applied to the support belt 21 by the auxiliary roller 423 (or the brush 425) of the auxiliary potential applying unit 42. The ground potential may be applied to the support belt 21 as an auxiliary potential by omitting the potential supply unit 424 and grounding the auxiliary roller 423. Accordingly, a steep distribution potential is applied to the glass substrate 9 while simplifying the configuration of the auxiliary potential applying unit 42.

  In the above-described embodiment, the distribution potential having a distribution in which the difference from the surface potential of the photoreceptor 312 gradually decreases as the distance from the transfer position is increased on both sides of the transfer position with respect to the Y direction parallel to the traveling direction of the glass substrate 9 during image formation. Is applied to the glass substrate 9, but the distribution potential may be applied only to the (+ Y) side or the (-Y) side of the transfer position. However, from the viewpoint of transferring the toner image from the photoconductor 312 onto the glass substrate 9 with higher accuracy, the surface potential of the photoconductor 312 increases with distance from the transfer position not only in one direction but also in the opposite direction to the transfer position. A distribution potential having a similar distribution in which the difference gradually decreases is applied to the glass substrate 9, and the photosensitive body 312 and the (+ Y) side and the (−Y) side of the transfer position as in the above embodiment. It is preferable to prevent the occurrence of discharge in the gap between the glass substrate 9.

  Further, in the image forming apparatus, for example, a stage is provided on which a glass substrate 9 is placed while being formed of a semiconductive material having a constant thickness, and the transfer unit 4 generates a distributed potential on this stage. Also good. In this case, the substrate moving mechanism is realized as a mechanism that horizontally moves the stage in the Y direction by a linear motor or a combination of a ball screw mechanism and a motor. As described above, the supporting member having a contact surface that contacts the glass substrate 9 in the vicinity of the transfer position, and the annular photosensitive member 312 (or the glass substrate 9 at the transfer position closest to the outer peripheral surface of the photosensitive member 312) Various moving mechanisms that move in the tangential direction of the intermediate transfer member 251) can be used. Depending on the design of the image forming apparatus, it is also possible to fix the glass substrate 9 and move the transfer unit and the process unit in the Y direction with respect to the glass substrate 9 to form a toner image on the glass substrate 9.

  The image forming apparatus may be used for applications other than the manufacture of color filters, and the processing target in the image forming apparatus may be a substrate other than the glass substrate 9 such as a semiconductor substrate or a printed wiring board. In the image forming apparatus, since the occurrence of electric discharge in the vicinity of the transfer position is prevented, a high transfer potential is applied to the toner image even on a substrate having a small capacitance formed of a material having a small thickness or a low dielectric constant. Alternatively, the electrostatic latent image can be accurately transferred and formed on the substrate, and substrates formed of various materials can be processed.

1 is a diagram illustrating a configuration of an image forming apparatus. It is a figure which shows the transfer position vicinity. It is a figure which shows the flow of the process which forms a toner image on a glass substrate. It is a figure which shows the electric potential which acts on a support belt. It is a figure which shows the other example of the transfer part. It is a figure which shows the further another example of a transcription | transfer part. It is a figure which shows the other example of an image forming apparatus. It is a figure which shows the other example which produces a distributed potential in the contact surface of a support belt. It is a figure which shows the further another example which produces distribution potential in the contact surface of a support belt.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1,1a Image forming apparatus 4,4a, 4b Transfer part 9 Glass substrate 21,21a, 21b Support belt 22 Substrate moving mechanism 25 Intermediate transfer part 31 Photosensitive drum 41, 41a Transfer potential applying part 42, 42a Auxiliary potential applying part 251 Intermediate Transfer body 312 Photoconductor 411, 421 Electrode 412, 422 Conductive rubber 413 Transfer roller 415 Corona discharger 423 Auxiliary roller 425 Brush S11a, S11b, S15 Step

Claims (12)

An image forming apparatus for forming a toner image or an electrostatic latent image on a substrate,
An original image holding unit that circulates and moves a cylindrical drum-like or flat belt-like annular member on the outer peripheral surface along which the toner image before transfer or the original image that is an electrostatic latent image is formed;
The substrate is moved in the same direction as the portion of the annular member at the same speed as the portion of the annular member at the transfer position while the transfer surface of the substrate is closest to the outer peripheral surface at a predetermined transfer position. A moving mechanism that moves in the direction of travel along the transfer surface;
When the original image on the outer peripheral surface is transferred onto the substrate at the transfer position, the annular member is moved away from the transfer position toward the one direction which is the traveling direction or the direction opposite to the traveling direction. A transfer portion that applies a potential having a distribution in which a difference from the surface potential gradually decreases to a surface of the substrate opposite to the transfer target surface;
An image forming apparatus comprising: The image forming apparatus according to claim 1,
A support member having a contact surface that contacts the surface of the substrate opposite to the transfer surface in the vicinity of the transfer position;
The image forming apparatus, wherein the transfer unit generates a potential having the distribution on the contact surface of the support member. The image forming apparatus according to claim 2,
The support member is formed of a semiconductive material having a constant thickness;
The transfer portion is
A first potential applying unit that applies a first potential to a position closest to the transfer position through the support member and a substrate on a surface opposite to the contact surface of the support member;
A second potential that is closer to the surface potential of the annular member than the first potential is applied to the support member at a position that is a predetermined distance away from the first potential applying portion in the one direction. A second potential applying unit that generates a potential having the distribution on the support member;
An image forming apparatus comprising: The image forming apparatus according to claim 3, wherein
At least one of the first potential applying unit and the second potential applying unit is formed by covering a periphery of the electrode to which the first potential or the second potential is applied with a conductive elastic material. And an image forming apparatus comprising a roller that contacts a surface of the support member opposite to the contact surface. The image forming apparatus according to claim 3, wherein
The image forming apparatus, wherein the first potential applying unit is a corona discharger. The image forming apparatus according to claim 3, wherein
The image forming apparatus, wherein the second potential applying unit includes a brush that is formed of a conductive material and that abuts against a surface of the support member opposite to the abutment surface. The image forming apparatus according to claim 1,
The surface potential of the annular member increases as the distribution of the potential applied to the surface of the substrate opposite to the surface to be transferred by the transfer portion moves away from the transfer position in a direction opposite to the one direction. An image forming apparatus, further comprising a distribution in which the difference between the two gradually decreases. The image forming apparatus according to claim 7,
A support member having a contact surface that contacts the surface of the substrate opposite to the transfer surface in the vicinity of the transfer position;
The image forming apparatus, wherein the transfer unit generates a potential having the distribution on the contact surface of the support member. The image forming apparatus according to claim 8, wherein
The support member is formed of a semiconductive material having a constant thickness;
The transfer portion is
A first potential applying unit that applies a first potential to a position closest to the transfer position via the support member and a substrate on a surface opposite to the contact surface of the support member;
The annular member is moved more than the first potential to the support member at a predetermined distance from the first potential applying portion in a direction away from the one direction and the one direction. Two second potential applying portions that generate a potential having the distribution on the support member by applying a second potential close to the surface potential;
An image forming apparatus comprising: An image forming apparatus according to any one of claims 3 to 6 and claim 9,
The image forming apparatus, wherein the second potential has a polarity opposite to the first potential or a ground potential. The image forming apparatus according to claim 1,
An image forming apparatus, wherein the original image is a toner image formed by applying liquid toner to the electrostatic latent image on the outer peripheral surface. An image forming method for forming a toner image or an electrostatic latent image on a substrate,
A circulating movement step of circulating and moving a cylindrical drum-like or flat belt-like annular member on which the toner image before transfer or an original image which is an electrostatic latent image is formed on the outer peripheral surface, along the outer peripheral surface;
In parallel with the circulation movement step, the substrate is moved at the same speed as the portion of the annular member at the transfer position while bringing the transfer surface of the substrate closest to the outer peripheral surface at a predetermined transfer position. A moving step of moving in the same direction as the part and in a traveling direction along the transfer surface;
In parallel with the movement step, a transfer step of transferring the original image on the outer peripheral surface onto the substrate at the transfer position;
With
In the transfer step, the potential having a distribution in which the difference from the surface potential of the annular member gradually decreases with distance from the transfer position toward the one direction which is the traveling direction or the direction opposite to the traveling direction. An image forming method, wherein the image forming method is provided on a surface of the substrate opposite to the surface to be transferred.

Images