JP5007815B2 - Developer transport structure and image forming apparatus - Google Patents

Description

  The present invention relates to a developer transport structure for transporting excess liquid developer stored in a developer storage section or the like generated in an image forming process, and an image forming apparatus using such a developer transport structure. .

  Various wet image forming apparatuses that develop a latent image using a high-viscosity liquid developer in which a toner composed of a solid component is dispersed in a liquid solvent and visualize the electrostatic latent image have been proposed. The developer used in this wet image forming apparatus suspends solids (toner particles) in a highly viscous organic solvent (carrier liquid) having electrical insulation properties such as silicon oil, mineral oil, and edible oil. The toner particles are extremely fine with a particle diameter of around 1 μm. By using such fine toner particles, the wet image forming apparatus can achieve higher image quality than a dry image forming apparatus using powder toner particles having a particle diameter of about 7 μm. The carrier liquid constituting the developer has a function of making the toner particles charged and further uniformly dispersed in addition to preventing the scattering of toner particles having a particle diameter of about 1 μm. It also has a role to make it easy to move by electric field action.

In such an image forming apparatus, a developer transport structure specialized for transporting the liquid developer must be used. As a developer transport structure, for example, one described in Patent Document 1 (Japanese Patent Laid-Open No. 5-57993) is known. Patent Document 1 discloses a developer conveying structure that supplies a developer containing toner to a developing position and mixes with a new developer replenished from a developer supply port. The developer is conveyed by the rotation of the developer, and the developer mixing / conveying unit adjacent to the developer and the developer storing unit for developing the developer from the developing roller onto the photosensitive member and storing the remaining developer are circulated. It is. In addition, when the developer is circulated between the developer mixing / conveying unit and the developer storing unit, a control unit capable of controlling the developer flow is also provided.
JP-A-5-57993

  In the above-mentioned patent document 1, since the developer circulates between the developer mixing / conveying unit and the developer storage unit adjacent to each other in a closed loop, supply of a new developer to be replenished from the developer supply port However, there is a problem in that although the gravity inflow to the developer mixing / conveying section is smoothly developed, the extra liquid developer carrying process generated in the image forming process is not taken into consideration.

  The excess liquid developer stored in the developer storage part generated in the image forming process is charged and the toner particles are aggregated or the toner concentration is not uniform, which makes handling difficult. There is also the problem of being.

  Further, since the surplus liquid developer is in a charged state, there is a problem that a situation occurs in which the developer cannot be conveyed due to electrostatic adsorption on the surface of the developer conveying screw or the developer mixing / conveying member.

  That is, when the image forming apparatus described in Patent Document 1 is used in the image forming apparatus, there is a problem that the recycling process or disposal process of the excess liquid developer is not smoothly performed.

The present invention is for solving the above-described problems, and the developer transport structure according to the present invention rotates with a spiral wing having a predetermined pitch and transports a liquid developer containing toner particles and a carrier liquid. A conveying screw; an inlet that is disposed at one end of a rotation shaft of the conveying screw and that sucks the liquid developer conveyed by the conveying screw; and stores the liquid developer; and the conveying screw is disposed, have a, a developer reservoir comprises a recess for covering the conveying screw rotation direction of the conveying screw has an arc angle of more than 180 °, the suction port of the axial direction of the conveyor screw The arc angle of the concave portion on the side is larger than the arc angle of the concave portion on the side opposite to the suction port in the axial direction of the conveying screw .

In the developer conveying structure according to the present invention, the conveying screw is fitted into the suction port.

An image forming apparatus according to the present invention includes an image carrier that carries an image developed with a liquid developer containing toner particles and a carrier liquid, an image carrier cleaning blade that cleans the image carrier, A spiral screw having a pitch of 5 mm is formed and rotated, and a conveying screw that conveys the liquid developer scraped by the image carrier cleaning blade is disposed at one end of a rotating shaft of the conveying screw, and the conveying screw The suction port through which the liquid developer transported in step S1 is sucked in and the liquid developer are stored and the transport screw is arranged so that the transport screw has a rotation direction of 180 ° or more with an arc angle. possess a developer reservoir conveying unit having a developer reservoir comprises a recess for covering the screw, wherein the side of said suction port in the axial direction of the conveyor screw Arc angle parts are characterized in that the angle is greater than the arc angle of the recess of the suction port and the opposite side in the axial direction of the conveying screw.

In addition, the image forming apparatus according to the present invention includes a developing roller that develops the image carrier, a developing roller cleaning blade that cleans the developing roller, and spiral blades having a predetermined pitch that are rotated to form the developing roller. The second developer screw that conveys the liquid developer scraped by the cleaning blade, and the liquid developer that is disposed at one end of the rotation shaft of the second conveyer screw and is conveyed by the second conveyer screw. A second suction port through which the agent is sucked and the liquid developer are stored, and the second conveying screw is arranged so that the rotation direction of the second conveying screw has an arc angle of 180 ° or more. A second developer storage section having a recess covering the second conveying screw.

In the image forming apparatus according to the present invention, the pitch of the spiral blades of the second conveying screw is shorter than the pitch of the spiral blades of the conveying screw.

  According to the developer transport structure of the present invention, it is possible to smoothly carry the surplus liquid developer transport process in which the toner particles are agglomerated or the toner density is not uniform. In addition, this makes it possible to smoothly perform the recycling process and disposal process of the excess liquid developer.

  Further, according to the developer transport structure of the present invention, it is possible to prevent the surplus liquid developer from being transported because the charged toner particles of the surplus liquid developer are prevented from being electrostatically adsorbed onto the surface of the transport member. Does not happen.

  In addition, according to the image forming apparatus using the developer transport structure of the present invention, the developer is developed by improving the transport efficiency of the excess liquid developer and moving away from the structure in which the developer is circulated in a closed loop. One part is transported from one part to another part and mixed with new developer, or toner particles are aggregated and toner density non-uniformity is eliminated to achieve desired dispersion, or it is discarded as unnecessary developer. Can be rejected.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a diagram showing main components constituting an image forming apparatus using a developer conveying structure according to an embodiment of the present invention. Development units 30Y, 30M, 30C, and 30K are arranged at the lower part of the image forming apparatus, and the intermediate transfer member 40 and the secondary transfer unit 60 Arranged at the top of the image forming apparatus.

  The image forming unit includes image carriers 10Y, 10M, 10C, and 10K, charging rollers 11Y, 11M, 11C, and 11K, and exposure units 12Y, 12M, 12C, and 12K (not shown). The exposure units 12Y, 12M, 12C, and 12K have an optical system such as a semiconductor laser, a polygon mirror, and an F-θ lens. The image bearing members 10Y, 10M, 10C, and 10K are provided by charging rollers 11Y, 11M, 11C, and 11K. Are uniformly charged and irradiated with a modulated laser beam based on the input image signal by the exposure units 12Y, 12M, 12C, and 12K, and charged image carriers 10Y, 10M, 10C, and 10K. An electrostatic latent image is formed thereon.

  The developing units 30Y, 30M, 30C, and 30K generally include liquid developers of respective colors including the developing rollers 20Y, 20M, 20C, and 20K, yellow (Y), magenta (M), cyan (C), and black (K). Developer containers (reservoirs) 31Y, 31M, 31C, 31K to be stored, anilox rollers 32Y for supplying liquid developers of these colors from the developer containers 31Y, 31M, 31C, 31K to the developing rollers 20Y, 20M, 20C, 20K, The electrostatic latent images formed on the image carriers 10Y, 10M, 10C, and 10K are developed with liquid developers of respective colors. Each of the developing units 30Y, 30M, 30C, and 30K is configured to be detachable from the image forming apparatus main body.

  The image carriers 10Y, 10M, 10C, and 10K are in contact with image carrier squeeze rollers 13Y, 13M, 13C, and 13K that exert a squeeze action thereon, and around the developing rollers 20Y, 20M, 20C, and 20K. In addition, toner compression rollers 22Y, 22M, 22C, and 22K that provide a compaction effect are provided. The toner compression rollers 22Y, 22M, 22C, and 22K may be in contact with the developing rollers 20Y, 20M, 20C, and 20K, or may be kept in a non-contact state.

  The intermediate transfer member 40 is an endless belt, and is stretched between the driving roller 41 and the tension roller 42, and is contacted with the image carriers 10Y, 10M, 10C, and 10K by the primary transfer portions 50Y, 50M, 50C, and 50K. It is rotationally driven by the driving roller 41 while in contact. The primary transfer units 50Y, 50M, 50C, and 50K are arranged such that the primary transfer rollers 51Y, 51M, 51C, and 51K are opposed to each other with the image transfer bodies 10Y, 10M, 10C, and 10K sandwiched between the intermediate transfer body 40 and the image transfer bodies 10Y, Using the contact position with 10M, 10C, and 10K as the transfer position, the developed toner images of the respective colors on the image carriers 10Y, 10M, 10C, and 10K are sequentially superimposed and transferred onto the intermediate transfer body 40 to obtain a full-color toner. Form an image.

  In the secondary transfer unit 60, a secondary transfer roller 61 is disposed opposite to the belt driving roller 41 with the intermediate transfer member 40 interposed therebetween, and a cleaning device including a secondary transfer roller cleaning blade 62 and a developer storage unit 63 is disposed. The Then, at the transfer position where the secondary transfer roller 61 is disposed, a single color toner image or a full color toner image formed on the intermediate transfer body 40 is conveyed on the sheet material conveyance path L such as paper, film, cloth, etc. Transfer to recording medium.

  Further, a fixing unit (not shown) is disposed in front of the path sheet material conveyance path L, and a single color toner image or a full color toner image transferred onto a recording medium such as paper is fused to the recording medium such as paper. And fix.

  Further, the tension roller 42 stretches the intermediate transfer body 40 together with the belt driving roller 41, and the intermediate transfer body cleaning blade 46, developer storage, and the like are stretched around the tension roller 42 of the intermediate transfer body 40. A cleaning device including the portion 47 is in contact with and disposed.

  Next, the image forming unit and the developing unit will be described. FIG. 2 is a cross-sectional view showing main components of the image forming unit and the developing unit. 3 is a diagram for explaining compaction by the toner compression roller 22Y, FIG. 4 is a diagram for explaining development by the developing roller 20Y, FIG. 5 is a diagram for explaining squeezing action by the image carrier squeeze roller 13Y, and FIG. 6 is an intermediate transfer member. It is a figure explaining the squeeze effect | action by the squeeze apparatus 52Y. Since the configurations of the image forming unit and the developing unit for each color are the same, the following description will be made based on the yellow (Y) image forming unit and the developing unit.

  The image forming unit includes a cleaning device including a latent image eraser 16Y, an image carrier cleaning blade 17Y, and a developer storage unit 18Y, a charging roller 11Y, an exposure unit 12Y, and a development unit along the rotation direction of the outer periphery of the image carrier 10Y. A cleaning device including a 30Y developing roller 20Y, an image carrier squeeze roller 13Y, and an image carrier squeeze roller cleaning blade 14Y as an auxiliary component is disposed. Further, on the outer periphery of the developing roller 20Y in the developing unit 30Y, a cleaning device including a developing roller cleaning blade 21Y and a developer storage unit 24Y, an anilox roller 32Y, and a toner compression roller 22Y are arranged.

  A carrier amount adjusting blade 23Y is provided on the outer periphery of the toner compression roller 22Y. Further, a part of the liquid developer supply roller 34Y and the anilox roller 32Y are accommodated in the liquid developer container 31Y. A primary transfer roller 51Y of the primary transfer portion is disposed along the intermediate transfer body 40 at a position facing the image carrier 10Y, and an intermediate transfer body squeeze roller 53Y, a backup roller 54Y, and an intermediate transfer are disposed downstream in the moving direction. An intermediate transfer body squeeze device 52Y including a body squeeze roller cleaning blade 55Y and a developer storage unit 56Y is disposed.

  The image carrier 10Y is a photosensitive drum made of a cylindrical member having a width wider than about 320 mm of the developing roller 20Y and a photosensitive layer formed on the outer peripheral surface. For example, the image carrier 10Y rotates in a clockwise direction as shown in FIG. To do. The photosensitive layer of the image carrier 10Y is composed of an amorphous silicon image carrier or the like. The charging roller 11Y is disposed upstream of the nip portion between the image carrier 10Y and the developing roller 20Y in the rotation direction of the image carrier 10Y, and a bias having the same polarity as the toner charging polarity is applied from a power supply device (not shown) to The carrier 10Y is charged. The exposure unit 12Y irradiates laser light onto the image carrier 10Y charged by the charging roller 11Y on the downstream side in the rotation direction of the image carrier 10Y with respect to the charging roller 11Y, thereby forming a latent image on the image carrier 10Y. To do.

  The developing unit 30Y includes a toner compression roller 22Y, a developer container 31Y that stores a liquid developer in which toner is dispersed in a carrier at a weight ratio of approximately 20%, a developing roller 20Y that carries the liquid developer, a liquid developer, and the like. Toner compression for bringing the liquid developer carried on the developing roller 20Y into a compaction state by stirring the agent to maintain a uniform dispersed state and supplying it to the developing roller 20Y, the regulating blade 33Y, the supply roller 34Y, and the liquid developer carried on the developing roller 20Y A developing roller cleaning blade 21Y for cleaning the roller 22Y and the developing roller 20Y is provided.

  FIG. 7 is a view showing the external shape of the anilox roller. The anilox roller 32Y and the supply roller 34Y are configured to rotate counter. When the anilox roller 32Y and the supply roller 34Y are in a counter-rotating state, a uniform liquid developer film can be formed from the supply roller 34Y to the anilox roller 32Y.

  The liquid developer accommodated in the developer container 31Y is a non-volatile liquid developer having high concentration and high viscosity and non-volatility at room temperature. That is, in the liquid developer in the present invention, a solid having an average particle diameter of 1 μm in which a colorant such as a pigment is dispersed in a thermoplastic resin is introduced into a liquid solvent such as an organic solvent, silicon oil, mineral oil, or edible oil. It is a liquid developer having a high viscosity (about 30 to 10,000 mPa · s) which is added together with a dispersant and has a toner solid content concentration of about 20%.

  In the developer container 31Y, the toner particles in the liquid developer have a positive charge. The liquid developer is agitated by the supply roller 34Y, and is pumped up from the developer container 31Y by rotating the anilox roller 32Y. It is done.

  The regulating blade 33Y is composed of an elastic blade whose surface is covered with an elastic body, a rubber portion made of urethane rubber or the like that comes into contact with the surface of the anilox roller 32Y, and a plate made of metal or the like that supports the rubber portion. Then, the film thickness and amount of the liquid developer carried and conveyed by the anilox roller 32Y made of an anilox roller are regulated and adjusted, and the amount of the liquid developer supplied to the developing roller 20Y is adjusted.

  The developing roller 20Y is a cylindrical member having a width of about 320 mm, and rotates counterclockwise around the rotation axis as shown in FIG. The developing roller 20Y is provided with an elastic layer made of polyurethane rubber, silicon rubber, NBR or the like on the outer periphery of an inner core made of metal such as iron. The developing roller cleaning blade 21Y is made of rubber or the like that comes into contact with the surface of the developing roller 20Y. The developing roller 20Y is arranged downstream of the developing nip portion where the developing roller 20Y comes into contact with the image carrier 10Y in the rotation direction of the developing roller 20Y. The liquid developer remaining on the developing roller 20Y is scraped off and removed.

  The toner compression roller 22Y is a cylindrical member and is in the form of an elastic roller formed by covering an elastic body 22-1Y like the developing roller 20Y as shown in FIG. For example, as shown in FIG. 2, it rotates clockwise in the direction opposite to the developing roller 20Y. The toner compression roller 22Y has means for increasing the charging bias on the surface of the developing roller 20Y. The developer conveyed by the developing roller 20Y is slidably contacted by the toner compression roller 22Y as shown in FIGS. A bias electric field is applied from the toner compression roller 22Y side toward the developing roller 20Y at the toner compression portion that forms the toner image. This bias application will be described in detail later. If the toner compression function is effective, the toner compression roller 22Y may be configured not to contact the developing roller 20Y.

  With this toner compression roller 22Y, as shown in FIG. 3, the toner T uniformly dispersed in the carrier C is moved to the developing roller 20Y side to be aggregated to form a so-called toner compression state T ′. A portion of the toner T ″ that has not been compressed with toner is carried and rotated in the direction of the arrow in the drawing, scraped off by the carrier amount adjusting blade 23Y, joined with the developer in the reservoir 31Y, and reused. On the other hand, the developer D, which is carried on the developing roller 20Y and compressed by toner, is applied to the image carrier 10Y by applying a desired electric field at the developing nip where the developing roller 20Y contacts the image carrier 10Y as shown in FIG. The image is developed corresponding to the latent image.

  The image carrier squeeze device is disposed on the downstream side of the developing device 20Y so as to face the image carrier 10Y, and collects excess developer of the toner image developed on the image carrier 10Y. As shown in FIG. 5, an image carrier squeeze roller 13Y comprising an elastic roller member that covers the surface with an elastic member 13-1Y and rotates in sliding contact with the image carrier 10Y, and press-slidably contacts the image carrier squeeze roller 13Y. And a cleaning blade 14Y for cleaning the surface, and as shown in FIG. 5, the excess carrier C and the originally unnecessary fog toner T ″ are collected from the developer D developed on the image carrier 10Y, The recovery capability of the surplus carrier C is based on the rotational direction of the image carrier squeeze roller 13Y and the peripheral speed of the surface of the image carrier 10Y. The desired recovery capability can be set by the relative peripheral speed difference of the surface of the body squeeze roller 13Y. When the image carrier 10Y is rotated in the counter direction, the recovery capability is increased, and the peripheral speed difference is reduced. Even if it is set to a large value, the recovery capability is enhanced, and further, this synergistic action is possible.

  In this embodiment, as an example, as shown in FIG. 5, the image carrier squeeze roller 13Y is rotated with the image carrier 10Y at substantially the same peripheral speed, and the weight ratio from the developer D developed on the image carrier 10Y is increased. The excess carrier C of about 5 to 10% is collected to reduce both rotational driving loads and suppress the disturbance effect on the visible toner image of the image carrier 10Y. Excess carrier C and unnecessary fog toner T ″ collected by the image carrier squeeze roller 13Y are collected from the image carrier squeeze roller 13Y by the action of the cleaning blade 14Y.

  In the primary transfer unit 50Y, the developer image developed on the image carrier 10Y is transferred to the intermediate transfer member 40 by the primary transfer roller 51Y. Here, the image carrier 10Y and the intermediate transfer member 40 are configured to move at a constant speed, reducing the driving load of rotation and movement, and suppressing the disturbance effect on the visible toner image of the image carrier 10Y. Yes. The primary transfer portion 50Y for the first color does not cause a color mixing phenomenon since it is the first primary transfer, but since the second and subsequent colors transfer different toner images onto the already transferred primary toner image portions and superimpose colors, the intermediate transfer body 40 is used. Due to the so-called reverse transfer phenomenon in which the toner moves from the image carrier 10 (M, C, K) to the image carrier 10 (M, C, K), the reverse transfer toner and the untransferred toner are mixed and are carried on the image carrier 10 (M, C, K) together with the excess carrier. Moved from the image carrier by the action of the cleaning blade 17 (M, C, K) and pooled.

  The intermediate transfer member squeeze device 52Y is disposed on the downstream side of the primary transfer unit 50Y, and removes excess carrier liquid from the intermediate transfer member 40 to increase the toner particle ratio in the visible image. In the stage where the carrier amount of the developer (toner dispersed in the carrier) transferred to the intermediate transfer body 40 by the transfer unit 50Y is secondarily transferred to the above-described final-stage sheet material and proceeds to the fixing process (not shown), In order to exhibit a preferable secondary transfer function and fixing function, excess carrier is further removed from the intermediate transfer body 40 when the approximate toner weight ratio of the desired dispersion state of the liquid developer does not reach about 40% to 60%. It is provided as a means. Similar to the image carrier squeeze device 52, the intermediate transfer member squeeze device 52Y has an intermediate transfer member squeeze roller 53Y composed of an elastic roller member that covers the surface with an elastic member and rotates in sliding contact with the image carrier 40, and the image carrier 40. 6 includes a backup roller 54Y disposed opposite to the intermediate transfer member squeeze roller 53Y, a cleaning blade 55Y that presses and slides against the intermediate transfer member squeeze roller 53Y, and a developer storage portion 56Y. As described above, the developer D that has been primarily transferred to the intermediate transfer body 40 has a function of recovering excess carrier C and originally unwanted fog toner T ″. The developer storage portion 56Y is provided on the downstream side of magenta. Also serves as a recovery mechanism for the carrier liquid recovered by the image carrier squeeze roller cleaning blade 14M. There.

  The surplus carrier collecting ability can be set to a desired collecting ability by the relative circumferential speed difference of the surface of the intermediate transfer member squeeze roller 53Y with respect to the rotation direction of the intermediate transfer member squeeze roller 53Y and the moving speed of the intermediate transfer member 40. When the intermediate transfer member 40 is rotated in the counter direction, the recovery capability is increased, and even when the peripheral speed difference is set to be large, the recovery capability is increased, and this synergistic action is also possible. In this embodiment, as an example, the intermediate transfer member squeeze roller 53Y rotates with the intermediate transfer member 40 at substantially the same peripheral speed, and a weight ratio of about 5 to 10% from the developer primarily transferred to the intermediate transfer member 40 is obtained. The excess carrier and fog toner are collected to reduce both rotational driving loads and to suppress the disturbance effect on the toner image of the intermediate transfer member 40.

  The first color intermediate squeeze squeeze part is the first intermediate squeeze squeeze, so no color mixing phenomenon occurs. However, after the second color, a different toner image is transferred to the already transferred primary toner image part and overlaid. Therefore, when the toner is transferred from the intermediate transfer body 40 to the intermediate transfer body squeeze roller 53Y, the toner is mixed in color and carried and moved by the intermediate transfer body squeeze roller 53Y together with the excess carrier, and the intermediate transfer body squeeze roller is operated by the action of the cleaning blade. Collected from 53Y and pooled. Further, when the squeeze ability by the image carrier 40 at the primary transfer portion upstream of the intermediate transfer member squeeze process and the squeeze ability of the image carrier squeeze roller 53Y are performed with sufficient ability, not all primary transfer processes are necessarily performed. There is no need to provide an intermediate transfer member squeeze device on the downstream side.

  In the liquid development image forming apparatus using the developer in which the toner is dispersed in the carrier of the present embodiment, the developer in which 20% of the toner is dispersed in 80% of the carrier by the approximate weight ratio is used. After the process, the toner weight ratio (solid content ratio) at the position immediately before the secondary transfer to the sheet material, that is, the so-called secondary transfer position is about 45% in the case of smooth paper such as coated paper, In this case, the control is performed with a target of around 55%, and around 60% in the case of rough paper with a coarse fiber fiber such as recycled paper. The developer initially stored in the developer container 31Y is in a state of being dispersed in the carrier at approximately a toner weight ratio of about 20%. However, in the case of development with a high image duty in the development on the image carrier 10Y, the toner In the case of development with a high consumption ratio of toner and a low image duty, the consumption ratio of toner is reduced. That is, the toner weight ratio of the developer stored in the developer container 31Y changes with the development of the image carrier 10Y, and this change is constantly monitored and the toner weight ratio is approximately 20%. It is necessary to maintain and control in a distributed state.

  The regulating blade 33Y contacts the surface of the anilox roller 32Y, scrapes off the other liquid developer leaving the liquid developer in the concave and convex grooves of the anilox pattern formed on the surface of the anilox roller 32Y, and the developing roller The amount of liquid developer supplied to 20Y is regulated. By such regulation, the film thickness of the liquid developer applied to the developing roller 20Y is quantified so as to be about 6 μm. The liquid developer scraped off by the regulating blade 33Y falls back to the developer container 31Y due to gravity, and the liquid developer that has not been scraped off by the regulating blade 33Y falls in the uneven grooves on the surface of the anilox roller 32Y. It is accommodated and applied to the surface of the developing roller 20Y by being pressed against the developing roller 20Y.

  The developing roller 20Y applied with the liquid developer by the anilox roller 32Y contacts the toner compression roller 22Y downstream of the nip portion with the anilox roller 32Y. A predetermined bias is applied to the developing roller 20Y, and a bias higher than that of the developing roller 20Y and having the same polarity as the charging polarity of the toner is applied to the toner compression roller 22Y. The bias application will be described later.

  Because of the bias application as described above, the toner particles in the liquid developer on the developing roller 20Y are aggregated and move toward the developing roller 20Y when passing through the nip with the toner compression roller 22Y as shown in FIG. . As a result, the toner particles are gradually combined and aggregated to form a film. When developing with the image carrier 10Y, the toner particles move from the developing roller 20Y to the image carrier 10Y quickly, and the image density is increased. Will improve.

  The image carrier 10Y is made of amorphous silicon, and after being charged by the charging roller 11Y upstream of the nip portion with the developing roller 20Y, a latent image is formed by the exposure unit 12Y. In the developing nip portion formed between the developing roller 20Y and the image carrier 10Y, the bias applied to the developing roller 20Y and the electric field formed by the latent image on the image carrier 10Y are as shown in FIG. Then, the toner particles T selectively move to the image portion on the image carrier 10Y, whereby a toner image is formed on the image carrier 10Y. Further, since the carrier liquid C is not affected by the electric field, as shown in FIG. 4, it is separated at the exit of the developing nip between the developing roller 20Y and the image carrier 10Y, and both the developing roller 20Y and the image carrier 10Y are separated. Adhere to. The image carrier 10Y that has passed through the development nip passes through the image carrier squeeze roller 13Y, and the excess carrier liquid C is removed as shown in FIG. 5 to increase the toner particle ratio in the visible image. The

  Next, the image carrier 10Y passes through the nip portion with the intermediate transfer body 40 in the primary transfer 50Y, and the primary transfer of the visible toner image to the intermediate transfer body 40 is performed. By applying a bias having a polarity opposite to the charging characteristics of the toner particles to the primary transfer roller 51Y, the toner is primarily transferred from the image carrier 10Y to the intermediate transfer member 40, and only the carrier liquid is transferred to the image carrier 10Y. Remains. On the downstream side in the rotation direction of the image carrier 10Y from the primary transfer portion, after the primary transfer, the electrostatic latent image in the image carrier 10Y is erased by the latent image eraser 16Y composed of a lamp or the like and remains on the image carrier 10Y. The carrier liquid is scraped off by the image carrier cleaning blade 17Y and collected by the developer storage unit 18Y.

  The toner image primarily transferred onto the intermediate transfer member 40 by the primary transfer unit 50Y passes through the intermediate transfer member squeeze device 52Y in order to scrape excess carriers on the intermediate transfer member 40. A predetermined bias is applied to the intermediate transfer member squeeze roller 53Y and the intermediate transfer member squeeze backup roller 54Y of the intermediate transfer member squeeze device 52Y, and an electric field is generated to press the toner particles against the intermediate transfer member 40 side. ing. Therefore, toner particles are not collected on the intermediate transfer member squeeze roller 53Y as shown in FIG. 6, and only the carrier liquid that is not affected by the electric field is transferred between the intermediate transfer member 40 and the intermediate transfer member squeeze roller 53Y. Collected by crying.

  The toner image on the intermediate transfer member 40 then proceeds to the secondary transfer unit 60 and enters the nip portion between the intermediate transfer member 40 and the secondary transfer roller 61. The nip width at this time is set to 3 mm. In the secondary transfer unit 60, predetermined biases are respectively applied to the secondary transfer roller 61 and the belt driving roller 41, whereby the toner image on the intermediate transfer member 40 is transferred to a recording medium such as paper.

  After passing through the secondary transfer unit 60, the intermediate transfer body 40 proceeds to the winding portion of the tension roller 42, the intermediate transfer body 40 is cleaned by the intermediate transfer body cleaning blade 46, and the primary transfer section 50 again. Head to.

  Next, the squeeze function of the secondary transfer roller 61 will be described. The sheet material is supplied in accordance with the timing at which the toner image overlaid on the intermediate transfer body 40 reaches the secondary transfer portion, and the toner image is secondarily transferred to the sheet material to proceed to a fixing step (not shown). When the final image formation on the sheet material is completed, but a sheet material supply trouble such as a jam occurs, the toner image is transferred in contact with the secondary transfer roller 61 without the sheet material interposed therebetween. Causes backside contamination. The secondary transfer roller 61 according to the present embodiment uses a plurality of photoconductors as means for improving the secondary transfer characteristics following the non-smooth sheet material surface, even if the surface is a non-smooth sheet material due to fibers or the like. An elastic roller having a surface coated with an elastic body for the same purpose as the elastic belt employed in the intermediate transfer body 40 that sequentially transfers the formed toner images, sequentially carries them, and carries them together to carry out secondary transfer onto the sheet material. It is composed. The secondary transfer roller cleaning blade 62 is provided as a means for removing the developer (toner dispersed in the carrier) transferred to the secondary transfer roller 61, collects the developer from the secondary transfer roller 61, and is pooled. . Note that the pooled developer is in a mixed color state and may contain foreign matters such as paper dust.

  Next, the cleaning device for the intermediate transfer member 40 will be described. When a sheet material supply trouble such as a jam occurs, not all the toner images are transferred to the secondary transfer roller 61 and collected, and a part remains on the intermediate transfer body 40. Further, even in a normal secondary transfer process, the toner image on the intermediate transfer member 40 is not 100% secondary transferred and transferred to the sheet material, and a secondary transfer residue of several percent occurs. The two types of unnecessary toner images are collected and pooled by an intermediate transfer member cleaning blade 46 and a developer storage unit 47 disposed downstream in the moving direction of the intermediate transfer member 40 for the next image formation.

  Next, transmission of driving force in the developing units 30Y, 30M, 30C, and 30K in which the rotating body drive transmission mechanism according to the embodiment is used will be described in detail. The rotating body drive transmission mechanism of the present invention transmits the rotational driving force from the image forming apparatus main body side to the image bearing members and rollers on the developing units 30Y, 30M, 30C, and 30K configured to be detachable from the main body. Used for.

  FIG. 8 is a diagram schematically showing a state where the rotating body drive transmission mechanism is used in the developing unit, FIG. 9 is a diagram showing a cross section of the rotating body drive transmission mechanism during coupling, and FIG. The body drive transmission mechanism is a diagram showing a cross section before coupling, and FIG. 11 is a diagram showing a cross section before each member of the rotary body drive transmission mechanism is completely engaged.

  In FIG. 8, reference numeral 100 denotes a rotating body drive transmission mechanism. In this embodiment, the rotating body drive transmission mechanism 100 rotates the image carrier 10Y, the image carrier squeeze roller 13Y, the developing roller 20Y, and the anilox roller 32Y. Used for driving force transmission. In the present embodiment, the rotating body drive transmission mechanism 100 is used for each of the above-described rollers, but may be used for one of the above-described rollers, or any of the above-described rollers. You may make it use for the combination of. Furthermore, you may apply the rotary body drive transmission mechanism 100 to rollers other than each said roller. In this embodiment, an example is shown in which the present invention is applied to an image forming apparatus using a liquid developer. However, the present invention is not limited to this and can also be applied to an image forming apparatus using dry toner.

  9 to 11, 110 is a torque transmission member, 120 is a rotation transmission member, 112 is a spring member, 113 is a flange portion, 114 is a key member, 130 is a contact surface portion for transmission, 140 is a rotating body drive source portion, Reference numeral 150 denotes a rotary passive member, 151 denotes a rotating body mounting flange, 152 denotes a ball bearing, 153 denotes a support member, and 160 denotes a concave surface for engagement.

  9 to 11 illustrate a rotating body drive transmission mechanism 100 according to the present invention that includes a rotating body (image carrier 10Y) that is rotatably supported and is configured to be detachable in the axial direction of the rotating body. It is a figure which shows the structure which consists of the rotation transmission member 120 etc. which carry out drive transmission from the rotary body drive source part 140 rotationally driven from a rotary body rotation-axis direction, and drive it.

  9 to 11 show a case where the image carrier 10Y receives a rotational driving force as a rotator from a rotator drive source unit 140 such as a motor, but the image carrier squeeze roller 13Y is used as a rotator. The same configuration can be adopted when the developing roller 20Y, the anilox roller 32Y and other rollers receive a rotational driving force.

  A rotation driving force is transmitted from the key member 114 of the rotating body drive source unit 140 to the rotation transmitting member 120 through the flange portion 113 fixed to the key member 114.

  A polygonal hole is formed in the rotation transmission member 120, and the polygonal transmission contact surface 130, which is the inner wall of the hole, transmits a rotational force to the torque transmission member 110. A torque transmission member 110 urged by a spring member 112 protrudes from the polygonal hole to the rotation transmission member 120.

  The rotation passive member 150 is provided with a similarly polygonal hole for receiving a rotational force via the torque transmission member 110, and the torque transmission member 110 is engaged with the engagement concave surface portion 160 which is the inner wall thereof. It is the composition to do.

  The rotary passive member 150 is fixed to the rotary body mounting flange portion 151 by a predetermined fixing means, and the rotary body (image carrier 10Y) attached to the rotary body mounting flange portion 151 is rotated along with the rotation of the rotary passive member 150. It is designed to rotate. The rotating body mounting flange portion 151 is attached to the support member 153 via the ball bearing 152 and is in a rotatable state.

  FIG. 10 shows a scene where the rotation passive member 150 is attached to the rotation transmission member 120 in the direction of the arrow in the figure, and the torque transmission member 110 loosely fitted to the rotation transmission member 120 is maintained in a completely free state without any restriction. is doing.

  FIG. 11 shows a scene in which the rotation passive member 150 is mounted at a predetermined position with respect to the rotation transmission member 120. The torque transmission member 110 is loosely fitted to the rotation transmission member 120. In a state where the relative phases of the contact surfaces do not match, the end surface of the torque transmission member 110 facing the end surface of the rotary passive member 150 contacts and the torque transmission member 110 moves against the pressing force of the spring member 112. The state is shown.

  In FIG. 12, the relative phase of the engaging concave surface 160 formed on the rotation passive member 150 matches the polygonal shape of the torque transmission member 110 that is rotationally driven from the rotation transmission member 120 and loosely engages with the rotation transmission member 12. The state where the torque transmission member 110 is engaged with the rotary passive member 15 during rotation by the pressing force of the spring member 112 is illustrated.

  Here, a predetermined clearance that allows the torque transmission member 110 to be fitted in the rotation direction and the direction perpendicular to the rotation axis may be provided in the engagement concave surface portion 160 of the hole of the rotation passive member 150. . With regard to the looseness relation between the rotation passive member 150 and the rotation transmission member 120 with the torque transmission member 110, the predetermined clearance provided in the rotation direction is particularly when the rotation body (image carrier 10Y) is driven to rotate from the rotation transmission member 120. What is necessary is just to provide and provide the clearance which can be inserted in the movement energizing side while the torque transmission member 110 rotates.

  A rotating body mounting flange 151 that is press-fitted into one end of a cylindrical rotating body (image carrier 10Y) is rotatably supported by a ball bearing 152. A rotating passive member 150 is screwed to the rotating body mounting flange 151. The position in the thrust direction is fixed.

  On the other hand, a rotating body drive source unit 140 (not shown in detail) is arranged facing the rotating body (image carrier 10Y) in the rotating body rotation axis direction, and a driving flange portion is connected to the rotating body driving section via a key member 114. The rotation is transmitted to 113. A rotation transmission member 120 is attached to the drive flange portion 113, and a rotating body drive transmission portion is configured together with the opposing rotation passive member 150.

  The rotary body drive transmission portion includes a columnar torque transmission member 110 having a polygonal shape extending in the rotation axis direction of the rotary body (image carrier 10Y), and corresponds to the polygonal shape of the torque transmission member 110. In this structure, a plurality of contact surfaces (engagement concave surface portions 160) that contact the polygonal surface are formed, and the torque transmission member 110 is provided with a predetermined clearance in the rotation direction and the direction perpendicular to the rotation axis.

  Next, the relationship between the polygonal shape of the torque transmission member 110, the polygonal hole provided in the rotation transmission member 120, the polygonal hole provided in the rotation passive member 150, and the rotating body drive transmission mechanism of the present invention. A mechanism for transmitting the rotational driving force will be described.

  FIG. 13 is a diagram for explaining the polygonal shape of the torque transmission member 110 and the detailed relationship between the rotation passive member 150 and the rotation transmission member 120, and shows a cross section taken along line AA of FIG.

  In FIG. 13, the polygonal shape of the torque transmission member 110 and the contact surfaces of the rotation passive member and the rotation transmission member are configured not to include surfaces parallel to each other.

  FIG. 13 schematically shows an example in which the polygonal shape of the torque transmission member 110 and the contact surfaces of the rotation passive member 150 and the rotation transmission member 120 are configured in an odd relationship, and FIG. 13A shows torque transmission from the rotation transmission member 120. The state in which the rotary passive member 150 is rotationally driven through the member 110 is schematically shown, and the rotary passive member 150 is illustrated by a two-dot chain line in preference to the drawing expression, although it does not conform to the AA cross-section drawing method. Yes.

  In FIG. 13B, the torque transmission member 110, the rotation passive member 150, and the rotation transmission member 120 are in a non-rotation drive state, and the torque transmission member 110 is rotationally passive by providing a predetermined clearance in the rotation direction and the direction perpendicular to the rotation axis. The member 150 and the rotation transmitting member 120 are loosely taken into account. 13A and 13B, the polygonal shape of the torque transmission member 110 and the contact surfaces of the rotation passive member 150 and the rotation transmission member 120 are configured in a five-corner relationship.

  Similarly, in FIGS. 13C and 13D, the polygonal shape of the torque transmission member 110 and the contact surfaces of the rotation passive member 150 and the rotation transmission member 120 are configured in a triangular relationship.

  In FIG. 13, the polygonal shape of the torque transmission member 110 and the shapes of the contact surfaces of the rotation passive member 150 and the rotation transmission member 120 are examples of different shapes. In a situation where the torque transmission member 110, the rotation passive member 150, and the rotation transmission member 120 are in a non-rotation driven state, the torque transmission member 110 is provided with a predetermined clearance in the rotation direction and the direction perpendicular to the rotation axis. 120.

  Then, when the rotation transmission member 120 is rotated in the direction of the arrow in the drawing and the rotation passive member 150 is rotationally driven via the torque transmission member 110, the contact surface of the rotation transmission member 120 contacts the torque transmission member 110, The torque transmission member 110 abuts on the contact surface of the rotary passive member 150 and is driven to rotate.

  During this rotational driving, the torque transmission member 110 loosely engaged with the contact surfaces of the rotation passive member 150 and the rotation transmission member 120 is automatically moved from the loose engagement state to a preferred position where it is self-stabilized, and the rotational axis is rotated. Automatic alignment.

  Therefore, it is not necessary to configure each member with a particularly high accuracy and can easily prevent the rotation fluctuation that occurs from one point of the rotation transmitting portion described in the conventional example.

  On the other hand, if the polygonal shape of the torque transmission member 110 and the rotation passive member 150 and the contact surface of the rotation transmission member 120 include parallel surfaces, a plurality of contact surfaces and rotation of the rotation passive member 150 are provided. Since the plurality of contact surfaces of the transmission member 120 have a parallel relationship with each other, if the rotational driving state is microscopically captured, it is self-stabilized from the looseness state under the influence of disturbance effects such as subtle transmission torque fluctuations and vibrations. The torque transmitting member 110 that has automatically moved to the preferred position and automatically aligned the rotation axis may move slightly along the parallel abutting surface and be subject to an unstable state. Depending on the behavior, there may be a slight fluctuation in the rotational speed of one rotation cycle.

  Therefore, when the polygonal shape of the torque transmission member 110 illustrated in FIG. 13 and the contact surfaces of the rotation passive member 150 and the rotation transmission member 120 are configured in an odd relationship, the plurality of contact surfaces and the rotation transmission member 120 of the rotation passive member 150 are configured. The plurality of contact surfaces are not in a parallel relationship with each other, so that the rotational drive state is microscopically captured, and it is preferable that it is self-stabilized from the loose-feeling state even under the influence of disturbance effects such as subtle transmission torque fluctuations and vibrations. The torque transmission member 110 that automatically moves to the position and automatically adjusts the rotational axis is capable of maintaining the automatic alignment state without moving, and has a subtle rotational speed. It does not cause fluctuations.

  As the most preferable mode for configuring the polygonal shape of the torque transmission member 110 and the contact surfaces of the rotation passive member 150 and the rotation transmission member 120 in an odd number relationship, the triangulated shape with the simplest division in view of manufacturability is considered. Is preferred.

  In addition, although the polygonal shape of the torque transmission member 110 illustrated in FIG. 13 and the shape of the contact surface of the rotation passive member 150 and the rotation transmission member 120 are illustrated with the shape of the torque transmission member 110 in common, the torque transmission is illustrated. The shape of the member 110 may be formed by changing the shape of the portion that freely engages with the rotation passive member 150 and the shape of the portion that loosely engages with the rotation transmission member 120, and the torque transmission member 110 is the rotation passive member 150. Although it is illustrated as an example in which the member 120 is loosely encased, a structure in which it is encased in the opposite manner may be used.

  9 to 12, the torque transmitting member 110 is moved and urged in one direction by a spring to stabilize the axial position in addition to the state in which the rotational axis is automatically aligned. Is not a requirement.

  Next, the case where the rotating body drive transmission mechanism of the present embodiment is applied to a plurality of rollers of the image forming apparatus will be considered. In this embodiment, the rotating body drive transmission mechanism 100 is used for transmitting rotational driving force to the image carrier 10Y, the image carrier squeeze roller 13Y, the developing roller 20Y, and the anilox roller 32Y. It is preferable that the corners in the polygonal shape such as the engaging concave surface portion 160 of the corresponding rotary passive member 150 are set so as not to be parallel to each other. This is because image disturbance due to resonance noise occurs when the positions where the corners of the respective rollers are in phase with each other are parallel to each other. Here, the corner means a polygonal apex such as the engaging concave surface 160.

  In particular, when the rotary member drive transmission mechanism 100 is applied to the image carrier 10Y and the anilox roller 32Y, it is better to set the corners of the polygonal shape not to be parallel to each other. This is because in the image forming apparatus, it is necessary to slightly change the rotation speed of the anilox roller 32Y according to the quality of the paper, the room temperature, and the like. In particular, it is preferable to prevent the interlocking with the image carrier 10Y. Because.

  FIG. 14 is a diagram illustrating the polygonal shape of the torque transmission member 110 and the detailed relationship between the rotation passive member 150 and the rotation transmission member 120, and the content and configuration described above in FIG. 13 are the same. The difference from the contents described above with reference to FIG. 13 is schematically illustrated in an exaggerated manner in which the rotational axes of the rotation passive member 150 and the rotation transmission member 120 are relatively displaced. However, the non-rotating state is not shown. Further, although it does not conform to the AA cross-section drawing method, the cross-sectional hatching of the rotation transmission member 120 is omitted with priority given to the drawing expression, and the rotation passive member 150 is illustrated by a two-dot chain line. Further, in the figure, G1 indicates the rotation axis of the rotation transmission member 120, G2 indicates the rotation axis of the rotation passive member 150, and G3 indicates the virtual rotation axis of the entire rotating body drive transmission mechanism.

  In FIG. 14, the rotation shafts of the rotation transmission member 120 and the rotation passive member 150 have a relative misalignment as shown, and the torque transmission member 110 is on the rotation transmission member 120 on one side and on the other side in FIG. Then, based on the mechanism described above, the rotary shaft core is automatically aligned by automatically moving to a preferred position where it is self-stable.

  That is, the torque transmission member 110 is rotated and transmitted from the rotation transmission member 120 to the rotary passive member 150 in a state where the torque transmission member 110 is inclined by the amount of relative core misalignment, and the virtual rotation shaft core G3 of the torque transmission member 110 in this state is the relative core. Intermediate position of displacement amount: A configuration in which the rotational drive is transmitted at a position that is approximately ½ of the relative misalignment amount.

  In the configuration shown in the conventional example, the rotational speed fluctuation of one rotation period occurs according to the relative center misalignment amount between the driving side and the driven side. Since the rotation axis is positioned at an intermediate position of the above-mentioned relative misalignment: approximately half of the relative misalignment, the rotational drive is transmitted, so that the rotational speed fluctuation in one rotation cycle can be halved.

  According to the configuration as described above, the rotational speed fluctuation of one rotation cycle is possible even if it is driven to rotate with a simple structure, without an extremely high-precision configuration, and with a shaft difference between the driving side and the driven side. Therefore, it is possible to provide a rotating body drive transmission mechanism that prevents the occurrence of the occurrence of the rotation and enables stable rotation drive transmission.

  Further, according to the above configuration, even if there is a certain amount of dimensional error, it does not become a defective product, which can contribute to an improvement in yield during mass production.

  Further, according to the image forming apparatus using the rotating body drive transmission mechanism as described above, jitter does not occur per one rotation period of the rotating body drive transmission mechanism, and image disturbance, unevenness, and the like do not occur.

  Next, the developer transport structure used in the developer reservoir 18Y of the image carrier 10Y of the image forming apparatus and the developer reservoir 24Y of the developing roller 20Y will be described.

  FIG. 15 is a perspective view of the developer transport structure in the developer reservoir 18Y, and FIG. 16 is a diagram schematically showing a cross-section of the main part of the developer transport structure according to the embodiment of the present invention. FIG. 16 is a BB cross section of FIG. Note that the developer transport structure used in the developer reservoir 24Y has substantially the same configuration.

  15 and 16, reference numeral 200 denotes a developer transport structure, 210 denotes a developer storage base, 211 denotes a developer storage base recess, 220 denotes a developer transport screw, 230 denotes a developer transport base, 231 denotes a suction port, and 240 denotes A pipe member, 241 is a nipple, 242 is a mounting portion, and 250 is a spring member.

  As shown in FIG. 2, the developer is primarily transferred from the image carrier 10Y to the intermediate transfer member 40, and the remaining developer is scraped off by the image carrier cleaning blade 17Y and stored in the developer reservoir 18Y. . The developer is stored in the developer storage base 210 of the developer storage base 210 of the developer transport structure 200 constituting the developer storage section 18Y, and is provided at one end in the longitudinal direction from the developer storage base 210. The developer is transported to the developer transport base 230.

  In the developer storage substrate recess 211 of the developer storage substrate 210, a developer conveying screw 220 is disposed in the axial direction by forming spiral wings of a predetermined pitch on the outer periphery of the cylindrical substrate portion and integrally supporting the rotation. In this configuration, the developer is conveyed. The developer storage substrate recess 211 is shaped to cover the developer transport screw 220, and its radius of curvature is set slightly larger than the suction port 231.

  The developer storage section 18Y forms a substantially U-shaped developer storage base recess 211 that opens upward in order to store the developer scraped off from the image carrier 10Y, and is one end of the developer storage base 210. The developer is discharged from the portion in the axial direction. A circular developer suction port 231 is formed in the developer transport base 230 at one end of the developer storage base 210, and the developer transport screw is provided in the suction port 231. This is a structure that rotates with 220 being inserted. The diameter of the suction port 231 is such that the developer transport screw 220 is substantially fitted therein, and this developer transport screw 220 extends from the developer storage substrate recess 211 into the suction port 231 of the developer transport substrate 230. By being present, the pumping action for sucking the developer into the suction port 231 is remarkable.

  When the developer conveying screw 220 is rotated in a state where the upper portion of the developer storage base 210 is opened to convey the developer and reach the portion where the developer conveying screw 220 is inserted into the suction port 231, this portion is reached. In this configuration, the developer is pumped and the developer is pumped to a desired position.

  The developer transport base 230 has a hole continuous from the suction port 231, and a pipe member 240 is attached to one end of the developer transport base 230 using a nipple 241 as illustrated. The developer conveying screw 220 extends to the pipe member 240, and a spring member 250 whose outer periphery is slidably contacted with the pipe member 240 is attached to the developer conveying screw 220 using an attachment portion. Yes.

  On the other hand, the developer stored in the developer storage section 18Y shown in FIG. 2 is the developer scraped off from the image carrier, and since the developer is in a charged state, the toner particles aggregate or other toner particles are collected. It becomes easy to be electrostatically attracted to the member. Therefore, when the developer is pumped by the above pump action, there is a possibility that the toner particles are electrostatically adsorbed on the inner surface of the transport path.

  Therefore, in this embodiment, a spring member 250 formed at a predetermined pitch is attached to the projecting end of the developer conveying screw 220 and is rotatably supported integrally with the developer conveying screw 220, and the outer peripheral surface of the spring member 250 and the developer are supported. The inner surface of the discharge port is configured with a slight gap, and even if toner particles are electrostatically adsorbed to the inner surface of the transport path by rotating in sliding contact with each other, scraping is possible and stable. Developer pumping can be realized.

  In FIG. 16, a pipe member 240 such as a developer conveying tube is continuously attached to the inlet 231 of the developer storage base 210 via a nipple 241 to form a developer conveying path and convey the developer to a desired position. In the same manner as described above, the inner surface of the pipe member 240, the developer conveying screw 220, and the spring member 250 are inserted with a slight gap to increase the developer pumping ability, and the pipe member. The toner particles adsorbed on the inner surface of 240 are scraped off to realize stable developer pressure feeding.

  The developer conveying screw 220 may be lengthened and fed to a desired position without using the spring member 250, but in this case, it is necessary to form the developer conveying path in a straight line. In the configuration in which the spring member 250 is inserted into the developer transport path, the object can be achieved even if the developer transport path is formed with a curvature, and there are few restrictions on forming the developer transport path.

  In this embodiment, an example of transporting the developer scraped from the image carrier 10 has been described. However, the present invention is not limited to this example, and can also be applied to parts provided in various places in FIG. .

  Next, a case where the developer conveying structure is applied to the developer reservoir 18Y of the image carrier 10Y and a case where the developer transport structure is applied to the developer reservoir 24Y of the developing roller 20Y will be described.

  The viscosity of the liquid developer scraped off by the image carrier cleaning blade 17Y of the image carrier 10Y is larger than the viscosity of the liquid developer scraped off by the developing roller cleaning blade 21Y of the developing roller 20Y.

  In the developer transport structure 200, transport of a low-viscosity liquid developer requires more transport processing capability. Accordingly, it is preferable that the pitch of the developer conveying screws 220 in the developer conveying structure 200 of the developer storing unit 24Y is shorter than the pitch of the developer conveying screws 220 in the developer conveying structure 200 of the developer storing unit 18Y. .

  Moreover, it is preferable that the rotation speed of the developer conveyance screw 220 in the developer conveyance structure 200 of the developer storage section 24Y is faster than the rotation speed of the developer conveyance screw 220 in the developer conveyance structure 200 of the developer storage section 18Y. .

  Further, the pitch of the 220 developer transport screws 220 in the developer transport structure 200 of the developer reservoir 24Y is made shorter than that of the developer reservoir 18Y, and the developer transport screw in the developer transport structure 200 of the developer reservoir 24Y. The rotational speed of 220 can be made faster than that of the developer storage unit 18Y.

  Next, the improvement of the developer conveying capability in the developer conveying structure will be described. FIG. 17 is a diagram schematically showing cross sections at three locations in the longitudinal direction of the developer conveying structure 200 according to the embodiment of the present invention.

  In FIG. 17, (a) shows the cross section closest to the developer transport base 230N, and (c) shows the cross section farthest from the developer transport base 230, as viewed from the longitudinal direction of the developer storage base 210. (B) shows a cross section at an intermediate level between the two. 17A to 17C are in a range in which the developer storage substrate recess 211 covers the developer transport screw 220. FIG.

  Such a range can be defined by an arc angle α in the drawing. That is, to what extent the developer transport screw 220 cross section is covered by the developer storage substrate recess 211 is defined by an angle α centered on the circle O of the developer transport screw 220 cross section.

  The liquid developer in which the toner particles are dispersed in the carrier liquid has a surface tension corresponding to the liquid, and has a characteristic of being adsorbed to the outer peripheral surface of the developer transport screw 220 and one part of the developer storage base 210. The developer adsorbed on the outer peripheral surface of the developer conveying screw 220 rotates together with the developer conveying screw 220, and the developer adsorbed on the developer storage unit base 210 has a position holding behavior.

  Therefore, the developer conveying function by the developer conveying screw 220 that rotates integrally with the spiral wings of a predetermined pitch formed on the outer periphery of the cylindrical base portion is that the arc surface along the outer circumferential surface of the developer conveying screw 220 is the same. Since it is achieved by the cooperating part, it is important to enlarge this cooperating part.

  As a result of various experiments based on this principle, the present inventors can conclude that a desired developer conveying ability can be obtained when the arc angle α shown in FIG. 17 is 180 ° or more. It was.

  Needless to say, the larger α is, the longer the portion where the developer conveying screw 220 and the arc surface along the outer peripheral surface cooperate with each other, and the developer conveying ability is improved.

  FIG. 17 shows an embodiment based on such knowledge. When the developer storage base 210 is viewed from the longitudinal direction, the developer transport capability is required in the vicinity of the developer transport base 230 where the scraped developer accumulates, and as shown in FIG. Is set so that α increases from (c) to (a).

  Next, a case where the developer conveying structure is applied to the developer reservoir 18Y of the image carrier 10Y and a case where the developer transport structure is applied to the developer reservoir 24Y of the developing roller 20Y will be described.

  As described above, the viscosity of the liquid developer scraped off from the image carrier 10Y is larger than the viscosity of the liquid developer scraped off from the developing roller 20Y.

  In the developer transport structure 200, since the transport of the liquid developer having a low viscosity requires more transport processing capability, the arc angle α in the developer storage unit 24Y that transports the liquid developer having a low viscosity is set as the developer. It is preferable to set larger than that of the reservoir 18Y.

  That is, the arc angle of the developer storage substrate recess 211 of the developer transport structure 200 that transports the liquid developer scraped off from the image carrier 10Y, and the developer that transports the liquid developer scraped off from the developing roller 20Y. When comparing the arc angle of the developer storage substrate recess 211 of the transport structure 200 in a plane perpendicular to the developer transport, it is desirable that the latter arc angle be set to be larger than the former arc angle.

  As described above, according to the configuration of the present invention, it is possible to smoothly carry the surplus liquid developer carrying process in which the toner particles are in a charged state or the toner particles are aggregated or the toner density is not uniform. In addition, this makes it possible to smoothly perform the recycling process and disposal process of the excess liquid developer.

  Further, according to the configuration of the present invention, since the situation where the charged toner particles of the excess liquid developer are electrostatically adsorbed on the surface of the conveying member is prevented, the excess liquid developer cannot be conveyed. do not do.

  In addition, according to the image forming apparatus using the developer transport structure having the above-described configuration, the developer is developed by improving the transport efficiency of the excess liquid developer and moving away from the structure in which the developer is circulated in a closed loop. One part is transported from one part to another part and mixed with new developer, or toner particles are aggregated and toner density non-uniformity is eliminated to achieve desired dispersion, or it is discarded as unnecessary developer. Can be rejected.

  Although various embodiments have been described above, embodiments configured by arbitrarily combining the components of the respective embodiments are also included in the present invention.

FIG. 3 is a diagram illustrating main components constituting an image forming apparatus using a developer conveyance structure according to an embodiment of the present invention. FIG. 3 is a cross-sectional view illustrating main components of an image forming unit and a developing unit. It is a figure explaining the compaction by the toner compression roller 22Y. It is a figure explaining the development by the developing roller 20Y. It is a figure explaining the squeeze effect | action by the image carrier squeeze roller 13Y. It is a figure explaining the squeeze effect | action by the intermediate transfer body squeeze apparatus 52Y. It is a figure which shows the external appearance shape of an anilox roller. It is a figure which shows typically a mode that the rotary body drive transmission mechanism is used for the image development unit. It is a figure which shows the cross section at the time of coupling of the rotary body drive transmission mechanism which concerns on embodiment of this invention. It is a figure which shows the cross section before a rotating body drive transmission mechanism is coupled. It is a figure which shows the cross section before each member of a rotary body drive transmission mechanism fully engages. It is a figure which shows the cross section at the time of coupling of a rotary body drive transmission mechanism. It is a figure explaining the detailed relationship of the polygonal shape of a torque transmission member, a rotation passive member, and a rotation transmission member. It is a figure explaining the detailed relationship of the polygonal shape of a torque transmission member, a rotation passive member, and a rotation transmission member. It is a perspective view of a developer transport structure in the developer storage section 18Y. It is a figure which shows typically the principal part cross section of the developer conveyance structure which concerns on embodiment of this invention. It is a figure which shows typically the cross section in the longitudinal direction 3 places of the developer conveyance structure which concerns on embodiment of this invention.

Explanation of symbols

10Y, 10M, 10C, 10K ... image carrier, 11Y, 11M, 11C, 11K ... charging roller, 12Y, 12M, 12C, 12K ... exposure unit, 13Y ... image carrier squeeze roller, 14Y: Image carrier squeeze roller cleaning blade, 16Y: Latent image eraser, 17Y: Image carrier cleaning blade, 18Y: Developer reservoir, 20Y, 20M, 20C, 20K ... Development Roller, 21Y ... developing roller cleaning blade, 22Y ... toner compression roller, 23Y ... carrier amount adjusting blade, 24Y ... developer reservoir, 30Y, 30M, 30C, 30K ... developing unit, 31Y, 31M, 31C, 31K ... developer container, 32Y, 32M, 32C, 32K ... anilox slot La, 31Y, 31M, 31C, 31K ... developer container, 33Y ... regulating blade, 34Y ... supply roller, 40 ... intermediate transfer member, 41, 42 ... belt drive roller, 45. ..Developer storage section, 46 ... intermediate transfer member cleaning blade, 47 ... developer storage section, 50Y, 50M, 50C, 50K ... primary transfer section, 51Y, 51M, 51C, 51K ... Primary transfer backup roller, 52Y, 52M, 52C, 52K ... Intermediate transfer member squeeze unit, 53Y ... Intermediate transfer member squeeze roller, 54Y ... Intermediate transfer member squeeze backup roller, 55Y ... Intermediate transfer member squeeze Roller cleaning blade, 56Y ... developer reservoir, 60 ... secondary transfer unit, 61 ... secondary transfer roller, 62. Secondary transfer roller cleaning blade, 63... Developer reservoir, 110... Torque transmission member, 120... Rotation transmission member, 112... Spring member, 113. -Key member, 130 ... Transmission contact surface part, 140 ... Rotating body drive source part, 150 ... Rotating passive member, 151 ... Rotating body mounting flange part, 152 ... Ball bearing, 153 ... Supporting member, 160 ... Concave surface for engagement, 200 ... Developer transport structure, 210 ... Developer storage substrate, 211 ... Developer storage substrate recess, 220 ... Developer transport Screws, 230 ... developer conveying base, 231 ... suction port, 240 ... pipe member, 241 ... nipple, 242 ... mounting portion, 250 ... spring member

Claims (5)

A spiral screw having a predetermined pitch is formed and rotated, and a conveying screw that conveys a liquid developer containing toner particles and a carrier liquid;
An inlet that is disposed at one end of the rotation shaft of the conveying screw and into which the liquid developer conveyed by the conveying screw is sucked;
A developer storage section that stores the liquid developer and includes a recess that covers the transport screw, the transport screw being disposed, the rotation direction of the transport screw having an arc angle of 180 ° or more, and
I have a,
An arc angle of the concave portion on the suction port side in the axial direction of the conveying screw is larger than an arc angle of the concave portion on the side opposite to the suction port in the axial direction of the conveying screw. Developer transport structure. The developer conveying structure according to claim 1 , wherein the conveying screw is fitted into the suction port. An image carrier that carries an image developed with a liquid developer containing toner particles and a carrier liquid;
An image carrier cleaning blade for cleaning the image carrier;
A spiral screw having a predetermined pitch is formed and rotated, and a conveyance screw that conveys the liquid developer scraped by the image carrier cleaning blade is disposed at one end of a rotation shaft of the conveyance screw, and the conveyance The suction port through which the liquid developer conveyed by the screw is sucked, and the liquid developer are stored and the conveying screw is arranged so that the rotation direction of the conveying screw has an arc angle of 180 ° or more. A developer storage and transport section having a developer storage section with a recess covering the transport screw;
I have a,
An arc angle of the concave portion on the suction port side in the axial direction of the conveying screw is larger than an arc angle of the concave portion on the side opposite to the suction port in the axial direction of the conveying screw. Image forming apparatus. A developing roller for developing the image carrier;
A developing roller cleaning blade for cleaning the developing roller;
A spiral wing having a predetermined pitch is formed and rotated, and is disposed at one end of a rotation shaft of the second conveyance screw and a second conveyance screw that conveys the liquid developer scraped by the developing roller cleaning blade. A second suction port through which the liquid developer transported by the second transport screw is sucked, and the liquid developer is stored, and the second transport screw is disposed and the second transport screw is disposed. A second developer reservoir having a recess that covers the second transport screw with an arc angle of 180 ° or more in the rotation direction of the transport screw;
An image forming apparatus according to claim 3 . The image forming apparatus according to claim 4 , wherein a pitch of spiral wings of the second conveying screw is shorter than a pitch of spiral wings of the conveying screw.

Images