JP4479187B2 - Developing device and image forming apparatus - Google Patents

Description

  The present invention relates to a developing device, an image forming apparatus, and an image forming system.

  As this type of image forming apparatus, for example, a photoconductor as an example of an image carrier for carrying a latent image and a latent image carried on the photoconductor by a liquid developer (hereinafter also simply referred to as a developer). 2. Description of the Related Art An image forming apparatus having a developing device for developing an image is known. Such an image forming apparatus forms a latent image on a photoreceptor when an image signal or the like is transmitted from an external device such as a host computer. Then, the latent image formed and carried on the photosensitive member reaches the developing position as the photosensitive member rotates, and is developed by the developing device, so that a developer image is formed on the photosensitive member.

  The developing device described above includes a developing roller as an example of a developer carrying member for carrying a developer, and a surface in order to realize the above-described function of developing a latent image formed on a photoreceptor. And a developer supplying roller as an example of a developer supplying member for supplying the developer held in the recessed portion to the developing roller. And a regulating blade as an example of a regulating means for regulating the amount of the developer above.

In such a developing device, the amount of developer on the developer supply roller is regulated by a regulation blade, and the developer whose amount is regulated is transferred from the developer supply roller to the development roller. The developer transferred to the developing roller is used for developing the latent image.
JP-A-11-84886

  As described above, the developer whose amount is regulated by the regulating blade is transferred from the developer supply roller to the developing roller, but the developer transferred to the developing roller has ribs (such as thick streaks). Pattern) may occur. When an image is formed by developing the latent image carried on the photosensitive member with the developer in which the rib is generated, the image quality is deteriorated.

  SUMMARY An advantage of some aspects of the invention is that it realizes a developing device, an image forming apparatus, and an image forming system that appropriately prevent deterioration in image quality.

The main present invention includes a developer carrying member for carrying a liquid developer,
The material is a metal and has a concave portion, which is a groove provided in a spiral shape , on the surface thereof, the surface being in pressure contact with the developer carrier, and the liquid developer held in the concave portion is the developer. A rotatable developer supply roller for supplying to the carrier;
A regulating blade for regulating the amount of liquid developer on the developer supply roller in contact with the surface of the developer supply roller;
In the developing device for developing the latent image carried on the image carrier by the liquid developer carried on the developer carrier,
An elastic layer, and wherein when viewed from the regulating blade is provided on the downstream side in the rotating direction of the developer supply roller, pressed against a state in which the developer supply roller which rotates being elastically deformed, by rotating A developer sucking roller that sucks a part of the liquid developer whose amount is regulated by the regulating blade and held in the recess,
The developer sucking roller is a developing device characterized in that an amount of the liquid developer held in the recess is made smaller than a volume of the recess holding the liquid developer.

  Other features of the present invention will become apparent from the description of the present specification and the accompanying drawings.

  According to the present invention, it is possible to realize a developing device, an image forming apparatus, and an image forming system that appropriately prevent deterioration in image quality.

  At least the following will be made clear by the description of the present specification and the accompanying drawings.

A developer carrying member for carrying the liquid developer, and a concave portion on the surface, the surface being in pressure contact with the developer carrying member, and the liquid developer held in the concave portion on the developer carrying member A developer supplying member for supplying and a regulating means for regulating the amount of the liquid developer on the developer supplying member, and an image is formed by the liquid developer carried on the developer carrying member. In a developing device for developing a latent image carried on a carrier, the amount of the liquid developer is regulated by the regulating means and held in the recess, and the liquid before being supplied to the developer carrier The developing device characterized in that the amount of the developer is smaller than the volume of the recess for holding the liquid developer.
The amount of the liquid developer that is regulated by the regulating means and is held in the recess, and before being supplied to the developer carrier, holds the liquid developer. When the volume is smaller than the volume of the concave portion, it is possible to appropriately prevent image quality deterioration.

The developer carrier and the developer supply member may be a development roller and a developer supply roller, respectively.
The restricting means may be a restricting blade having elasticity, and the restricting blade may be in contact with the surface of the developer supply roller to restrict the amount of the liquid developer on the developer supply roller.
In such a case, the configuration of the restricting means becomes simple.

The developing roller may have an elastic portion, and the developer supply roller may supply the liquid developer to the developing roller with the surface being in pressure contact with the elastic portion.
In this way, the developer is more appropriately transferred from the developer supply roller to the developing roller.

Further, the hardness of the contact portion of the regulating blade on the surface of the developer supply roller is lower than the hardness of the elastic portion of the pressure contact portion on the surface of the developer supply roller. Good.
In such a case, the regulating blade properly bites into the recess to prevent the occurrence of ribs, and the elastic part of the developing roller bites into the groove too much, so that an excessive amount of liquid developer is transferred to the developing roller. It becomes possible to suppress the demerits that have been made.

The rotation direction of the developing roller may be opposite to the rotation direction of the developer supply roller.
In this way, it is possible to prevent excessive rotational resistance from occurring at the pressure contact portions of both rollers.

The material of the developer supply roller may be metal.
In such a case, it is possible to more appropriately bite the regulating blade and the elastic portion of the developing roller into the concave portion of the developer supply roller.

The material of the regulating blade and the material of the elastic part of the developing roller may both be rubber.
The liquid developer may be a non-volatile liquid developer that is non-volatile at normal temperature.
In such a case, the effect described above, that is, the effect of preventing the deterioration of the image quality by suppressing the generation of the ribs is more effectively exhibited.

  Also, a developer carrying member for carrying the liquid developer and a concave portion on the surface, the surface is pressed against the developer carrying member, and the liquid developer held in the concave portion is supported by the developer carrying member. A developer supply member for supplying to the body and a regulating means for regulating the amount of the liquid developer on the developer supply member, and the liquid developer carried on the developer carrier In the developing device for developing the latent image carried on the image carrier, the amount of the liquid developer is regulated by the regulating means and is held in the concave portion before being supplied to the developer carrier. The amount of the liquid developer is smaller than the volume of the recess holding the liquid developer, and the developer carrier and the developer supply member are respectively a development roller and a developer supply roller. The regulating means is a regulating blade having elasticity. The regulating blade abuts on the surface of the developer supply roller to regulate the amount of liquid developer on the developer supply roller, the developing roller has an elastic portion, and the developer supply roller The surface is pressed against the elastic portion to supply the liquid developer to the developing roller, and the hardness of the contact portion of the regulating blade to the surface of the developer supplying roller is the developer of the elastic portion. The hardness of the pressure contact portion to the surface of the supply roller is lower, the rotation direction of the developing roller is opposite to the rotation direction of the developer supply roller, and the material of the developer supply roller is metal The material of the regulating blade and the material of the elastic part of the developing roller are both rubber, and the liquid developer is a non-volatile liquid developer that is non-volatile at room temperature. Is also feasible.

An image carrier for carrying a latent image; a developer carrier for carrying a liquid developer; and a concave portion on a surface, the surface being pressed against the developer carrier, and the concave portion A developer supply member for supplying the liquid developer held in the developer carrier to the developer carrier, and a regulating means for regulating the amount of the liquid developer on the developer supply member, And a developing device that develops the latent image carried on the image carrier by the liquid developer carried on the developer carrier. The amount of the liquid developer held before being supplied to the developer carrier is less than the volume of the concave portion holding the liquid developer. An apparatus is also feasible.
According to such an image forming apparatus, it is possible to appropriately prevent deterioration in image quality.

Further, the computer and an image forming apparatus connectable to the computer have an image carrier for carrying a latent image, a developer carrier for carrying a liquid developer, and a recess on the surface. And a developer supplying member for supplying the liquid developer held in the concave portion to the developer carrying member by pressing the surface against the developer carrying member, and liquid developing on the developer supplying member. And a developing device that develops the latent image carried on the image carrier by the liquid developer carried on the developer carrier. In the image forming system having the forming device, the amount of the liquid developer that is regulated by the regulating means and is held in the recess, and before being supplied to the developer carrier Is a container for the recess for holding the liquid developer. Image forming system, characterized in that less than also feasible.
The image forming system realized in this way is a system superior to the conventional system as a whole system.

=== Example of Overall Configuration of Image Forming Apparatus ===
Next, an outline of a laser beam printer (hereinafter also referred to as a printer) 10 as an example of the image forming apparatus will be described with reference to FIG. FIG. 1 is a diagram illustrating main components constituting the printer 10. In FIG. 1, the vertical direction is indicated by arrows. For example, the developing units 50Y, 50M, 50C, and 50K are arranged in the lower part of the printer 10, and the intermediate transfer member 70 is arranged in the upper part of the printer 10. Is arranged.

  As shown in FIG. 1, the printer 10 according to the present embodiment includes four developing units 15Y, 15M, 15C, and 15K, an intermediate transfer member 70, a secondary transfer unit 80, and a fixing unit (not shown). The display unit includes a liquid crystal panel that serves as an informing means for the user, and a control unit 100 (FIG. 2) that controls these units and operates as a printer.

  The developing units 15Y, 15M, 15C, and 15K have a function of developing a latent image with a yellow (Y) developer, a magenta (M) developer, a cyan (C) developer, and a black (K) developer, respectively. ing. Since the developing units 15Y, 15M, 15C, and 15K have the same configuration, the developing unit 15Y will be described below.

  As shown in FIG. 1, the developing unit 15Y includes a charging unit 30Y, an exposure unit 40Y, a developing unit 50Y as an example of a developing device, and a primary transfer unit along the rotation direction of a photoconductor 20Y as an example of an image carrier. 60Y, a charge eliminating unit 73Y, and a photoreceptor cleaning unit 75Y.

  The photoreceptor 20Y has a cylindrical base material and a photosensitive layer formed on the outer peripheral surface thereof, and is rotatable about a central axis. In the present embodiment, as shown by an arrow in FIG. Rotate clockwise.

  The charging unit 30Y is a device for charging the photoconductor 20Y, and the exposure unit 40Y is a device for forming a latent image on the photoconductor 20Y charged by irradiating a laser. The exposure unit 40Y has a semiconductor laser, a polygon mirror, an F-θ lens, and the like, and charges the modulated laser based on an image signal input from a host computer (not shown) such as a personal computer or a word processor. Irradiation is performed on the photoconductor 20Y.

  The developing unit 50Y is a device for developing the latent image formed on the photoreceptor 20Y using a yellow (Y) developer. Details of the developing unit 50Y will be described later.

The primary transfer unit 60Y is a device for transferring the yellow developer image formed on the photoreceptor 20Y to the intermediate transfer body 70. When the four color developers are sequentially transferred by the primary transfer units 60Y, 60M, 60C, and 60K, a full color developer image is formed on the intermediate transfer member 70.
The intermediate transfer member 70 is an endless belt stretched around a plurality of support rollers, and is driven to rotate while contacting the photoreceptors 20Y, 20M, 20C, and 20K.
The secondary transfer unit 80 is a device for transferring a single color developer image or a full color developer image formed on the intermediate transfer body 70 to a medium such as paper, film, or cloth.
A fixing unit (not shown) is a device for fusing a single color developer image or a full color developer image transferred onto a medium onto a medium such as paper to form a permanent image.
The neutralization unit 73Y is a device that removes residual charges on the photoreceptor 20Y after the developer image is transferred onto the intermediate transfer body 70 by the primary transfer unit 60Y.

  The photosensitive member cleaning unit 75Y has a rubber photosensitive member cleaning blade 76Y that is in contact with the surface of the photosensitive member 20Y. After the developer image is transferred onto the intermediate transfer member 70 by the primary transfer unit 60Y, the photosensitive member cleaning unit 75Y is photosensitive. This is a device for scraping and removing the developer remaining on the body 20Y by the photoreceptor cleaning blade 76Y.

  As shown in FIG. 2, the control unit 100 includes a main controller 101 and a unit controller 102. An image signal and a control signal are input to the main controller 101, and in response to a command based on the image signal and the control signal. A unit controller 102 controls each of the units and forms an image.

  Next, the operation of the printer 10 configured as described above will be described with reference to other components.

  First, when an image signal and a control signal from a host computer (not shown) are input to the main controller 101 of the printer 10 via the interface (I / F) 112, the unit controller 102 based on a command from the main controller 101. Under the control, the photoconductors 20Y, 20M, 20C, and 20K, the developing rollers (described later) provided in the developing units 50Y, 50M, 50C, and 50K, the intermediate transfer body 70, and the like rotate. The photoconductors 20Y, 20M, 20C, and 20K are sequentially charged by the charging units 30Y, 30M, 30C, and 30K at the charging positions while rotating.

  The charged regions of the photoconductors 20Y, 20M, 20C, and 20K reach the exposure position as the photoconductors 20Y, 20M, 20C, and 20K rotate, and are exposed to yellow Y and magenta by the exposure units 40Y, 40M, 40C, and 40K. A latent image corresponding to the image information of M, cyan C, and black K is formed in the area.

  The latent images formed on the photoreceptors 20Y, 20M, 20C, and 20K reach the development position as the photoreceptors 20Y, 20M, 20C, and 20K rotate, and are developed by the development units 50Y, 50M, 50C, and 50K. . As a result, developer images are formed on the photoreceptors 20Y, 20M, 20C, and 20K.

  The developer images formed on the photoconductors 20Y, 20M, 20C, and 20K reach the primary transfer position as the photoconductors 20Y, 20M, 20C, and 20K rotate, and are transferred by the primary transfer units 60Y, 60M, 60C, and 60K. Then, it is transferred to the intermediate transfer body 70. At this time, a primary transfer voltage having a polarity opposite to the charging polarity of the developer is applied to the primary transfer units 60Y, 60M, 60C, and 60K. As a result, the four color developer images formed on the respective photoconductors 20Y, 20M, 20C, and 20K are transferred to overlap with the intermediate transfer member 70, and a full color developer image is formed on the intermediate transfer member 70. Is done.

The full color developer image formed on the intermediate transfer member 70 reaches the secondary transfer position as the intermediate transfer member 70 rotates, and is transferred to the medium by the secondary transfer unit 80. The medium is transported from a paper feed tray (not shown) to the secondary transfer unit 80 via various rollers (the arrows in FIG. 1 indicate the transport direction of the medium). When performing the transfer operation, the secondary transfer unit 80 is pressed against the intermediate transfer body 70 and a secondary transfer voltage is applied.
The full color developer image transferred to the medium is heated and pressed by the fixing unit and fused to the medium.

  On the other hand, the photoreceptors 20Y, 20M, 20C, and 20K are neutralized by the neutralization units 73Y, 73M, 73C, and 73K after passing the primary transfer position, and are further supported by the photoreceptor cleaning units 75Y, 75M, 75C, and 75K. The developer adhering to the surface is scraped off by the photoconductor cleaning blades 76Y, 76M, 76C, and 76K to prepare for charging to form the next latent image. The developer that has been scraped off is collected in a remaining developer collecting section provided in the photoreceptor cleaning units 75Y, 75M, 75C, and 75K.

=== Overview of Control Unit ===
Next, the configuration of the control unit 100 will be described with reference to FIG. The main controller 101 of the control unit 100 is connected to a host computer via an interface 112 and includes an image memory 113 for storing image signals input from the host computer. The unit controller 102 includes units (charging units 30Y, 30M, 30C, and 30K, exposure units 40Y, 40M, 40C, and 40K, developing units 50Y, 50M, 50C, and 50K, primary transfer units 60Y, 60M, and 60C, and the like. 60K, static elimination units 73Y, 73M, 73C, 73K, photoconductor cleaning units 75Y, 75M, 75C, 75K, secondary transfer unit 80, fixing unit, display unit), and signals from sensors included in these , Each unit is controlled based on a signal input from the main controller 101 while detecting the state of each unit.

=== Configuration Example of Development Unit ===
Next, a configuration example of the developing unit will be described with reference to FIGS. 3 to 9C. FIG. 3 is a cross-sectional view showing main components of the developing unit. FIG. 4 is a conceptual perspective view showing the surface of the developer supply roller 550. 5A to 5E are views showing the shape of a recess provided on the surface of the developer supply roller 550. FIG. FIG. 6 is a schematic diagram illustrating the trail regulation of the regulation blade 560. 7, 8A, 8B, 8C, 9A, 9B, and 9C will be described later. In FIG. 3, the vertical direction is indicated by arrows as in FIG. 1. For example, the developing roller 510 is above the developer pumping roller 540.

  The printer 10 includes, as developing units, a black developing unit 50K containing black (K) developer, a magenta developing unit 50M containing magenta (M) developer, and a cyan developing unit 50C containing cyan (C) developer. , And a yellow developing unit 50Y containing a yellow (Y) developer is provided. Since each developing unit has the same configuration, the yellow developing unit 50Y will be described below.

  The yellow developing unit 50Y includes a developing roller 510 as an example of a developer carrier, a developer container 530, a developer scooping roller 540, a developer supply roller 550 as an example of a developer supply member, and a regulating unit. As an example, a regulation blade 560 and a developing roller cleaning unit 570 are provided.

  The developer storage unit 530 stores a developer D for developing the latent image formed on the photoconductor 20Y. The developer D accommodated in the developer accommodating portion 530 has a low concentration (about 1 to 2 wt%) and a low viscosity with Isopar (trademark: exon) as a carrier, which is generally used conventionally. It is not a volatile liquid developer having volatility, but a non-volatile liquid developer D having a high concentration and high viscosity and having non-volatility at room temperature. That is, the liquid developer D according to the present embodiment has a high concentration of toner particles made of resin, pigment, and the like having an average particle diameter of about 0.1 to 5 μm in a non-volatile and insulating carrier liquid such as silicone oil ( Developer D having a high viscosity (about 100 to 10,000 mPa · s) dispersed in about 5 to 40 wt%.

  The developer pump-up roller 540 pumps up the developer D stored in the developer storage unit 530 and conveys it to the developer supply roller 550. The lower part of the developer pumping roller 540 is immersed in the developer D accommodated in the developer accommodating portion 530, and is separated from the developer supply roller 550 with a width of about 1 mm.

  Further, the developer scooping roller 540 can rotate around its central axis, and the central axis is below the rotational central axis of the developer supply roller 550. Further, the developer scooping roller 540 rotates in the same direction (clockwise in FIG. 3) as the rotation direction of the developer supply roller 550 (clockwise in FIG. 3). The developer pump-up roller 540 has a function of pumping up the developer D stored in the developer storage section 530 and transporting it to the developer supply roller 550, and developing the developer D in an appropriate state. It also has a function of stirring the agent D.

  The developer supply roller 550 supplies the developer D conveyed from the developer container 530 by the developer pumping roller 540 to the developing roller 510. This developer supply roller is formed by uniformly and spirally forming a groove 550a as an example of a recess as shown in FIG. 4 on the surface of a metallic roller such as iron, and having a diameter of about 25 mm. The developer supply roller 550 in the present embodiment includes a groove 550a having a trapezoidal cross section as shown in FIG. 5A as the concave portion. For example, a depression having a shape as shown in FIG. 5D or FIG. 5E is provided. A large number of developer supply rollers 550 may be provided. Further, as the groove, instead of the groove 550a as shown in FIG. 5A, for example, a groove having an inverted triangular cross section as shown in FIG. 5B may be provided, or a semicircular cross section as shown in FIG. 5C may be provided. You may provide the groove | channel which has. As shown in FIG. 5A, the groove dimensions of the developer supply roller 550 in the present embodiment are a groove pitch of about 170 μm, a peak width of about 45 μm, a valley width of about 30 μm, and a groove depth of about 50 μm.

  Further, the developer supply roller 550 has a surface pressed against an elastic layer described later of the development roller 510 in order to appropriately transfer the developer D on the developer supply roller 550 to the development roller 510. ing. Further, the developer supply roller 550 can rotate around its central axis, and the central axis is below the rotation central axis of the developing roller 510. Further, the developer supply roller 550 rotates in a direction (clockwise in FIG. 3) opposite to the rotation direction of the developing roller 510 (counterclockwise in FIG. 3).

  The regulation blade 560 contacts the surface of the developer supply roller 550 and regulates the amount of the developer D on the developer supply roller. That is, the regulation blade 560 plays a role of scraping off the excess developer on the developer supply roller 550 and measuring the developer D on the developer supply roller 550 supplied to the development roller 510. The restriction blade 560 is made of urethane rubber as an elastic body, and is supported by a restriction blade support member 562 made of metal such as iron. The rubber hardness of the regulation blade 560 is about 62 degrees according to JIS-A, and the hardness (about 62 degrees) of the contact portion of the regulation blade 560 with the surface of the developer supply roller 550 is about the developing roller described later. This is lower than the hardness (about 85 degrees) of the pressure contact portion of the elastic body layer 510 to the surface of the developer supply roller 550.

  Further, the edge 560a of the regulating blade 560 is in contact with the surface of the developer supply roller 550, and so-called edge regulation is performed. Further, as shown in FIG. 6, the regulating blade 560 is disposed so that the tip thereof faces the downstream side in the rotation direction of the developer supply roller 550, and performs so-called trail regulation. As shown in FIG. 6, in this embodiment, the trail angle is about 10 degrees.

  The developing roller 510 carries the developer D and conveys it to the developing position facing the photoconductor 20Y in order to develop the latent image carried on the photoconductor 20Y with the developer D. The developing roller 510 is provided with an elastic layer as an example of an elastic portion having conductivity on the outer peripheral portion of an inner core made of metal such as iron, and has a diameter of about 20 mm. The elastic body layer has a two-layer structure. As the inner layer, urethane rubber having a rubber hardness of about 30 degrees JIS-A and a thickness of about 5 mm is used, and as the surface layer (outer layer), the rubber hardness is JIS. A urethane rubber having a thickness of about 30 μm at about 85 ° A is provided. The developing roller 510 is in pressure contact with the developer supply roller 550 and the photoreceptor 20Y in a state where the surface layer is a pressure contact portion and is elastically deformed.

  Further, the developing roller 510 can rotate around its central axis, and the central axis is below the rotational central axis of the photoconductor 20Y. Further, the developing roller 510 rotates in a direction (counterclockwise in FIG. 3) opposite to the rotation direction of the photoreceptor 20Y (clockwise in FIG. 3). When developing the latent image formed on the photoconductor 20Y, an electric field is formed between the developing roller 510 and the photoconductor 20Y.

  The developing roller cleaning unit 570 has a rubber developing roller cleaning blade 571 in contact with the surface of the developing roller 510, and the developer D remaining on the developing roller 510 after development is performed at the developing position. Is scraped off by the developing roller cleaning blade 571 and removed.

  In the yellow developing unit 50Y configured as described above, the developer pumping roller 540 rotates around its central axis, thereby pumping up the developer D stored in the developer storing unit 530 and developing the developer supply roller 550. Transport to.

  The developer D conveyed to the developer supply roller 550 reaches the contact position of the regulating blade 560 by the rotation of the developer supply roller 550. Then, when passing through the contact position, the excess amount of the developer D is scraped off by the regulating blade 560, and the amount of the developer D supplied to the developing roller 510 is measured. That is, since the developer supply roller 550 is provided with the groove 550a as described above, the regulating blade 560 that contacts the developer supply roller 550 causes the developer D on the developer supply roller 550 to enter the groove 550a. The retained developer D is left and scraped off. Further, since the dimension of the groove 550a is determined so that the developer amount of the developer D supplied to the developing roller 510 is an appropriate amount, the regulating blade 560 causes the developer D on the developer supply roller 550 to be removed. When scraped off, the developer D measured to an appropriate amount by the groove 550a remains in the groove 550a.

  Attention is now directed to FIG. FIG. 7 is an enlarged conceptual diagram showing a state where the regulating blade 560 is in contact with the surface of the developer supply roller 550. As described above, since the regulation blade 560 according to the present embodiment is an elastic body, the regulation blade 560 is elastically deformed and bites into the groove 550a and holds the developer D held in the groove 550a as shown in FIG. Can be scraped off. Therefore, the amount of the developer D that is regulated by the regulation blade 560 and is held in the groove 550 a before being supplied to the developing roller 510 is held by the developer D. It becomes less than the volume of the groove 550a (FIG. 9A).

  The developer D held in the groove 550 a of the developer supply roller 550 reaches a pressure contact position with the development roller 510 by further rotation of the developer supply roller 550. The developer D that has reached the pressure contact position is transferred from the developer supply roller 550 to the development roller 510 due to the pressure generated by the pressure contact between the developer supply roller 550 and the development roller 510, and is transferred onto the development roller 510. A thin film of developer D is formed.

  The developer D thin film formed on the developing roller 510 in this manner reaches the developing position (that is, the pressure contact position with the photoconductor 20Y) facing the photoconductor 20Y by the rotation of the developing roller 510, and the development The latent image formed on the photoconductor 20Y is subjected to development at a position under an electric field of a predetermined magnitude. The developer D on the developing roller 510 that has passed the developing position reaches the contact position of the developing roller cleaning blade 571 as the developing roller 510 further rotates. When passing through the contact position, the developer D attached to the surface of the developing roller 510 is scraped off by the developing roller cleaning blade 571, and the developer D thus scraped off is removed from the developing roller cleaning unit. It is collected in a residual developer collecting unit provided in 570.

  As described above, in the present embodiment, the amount of the liquid developer that is regulated by the regulating blade 560 and is held in the groove 550a before being supplied to the developing roller 510 is , The volume of the groove 550a holding the liquid developer becomes smaller. In such a case, it is possible to appropriately prevent image quality degradation.

  That is, as described in the section of the problem to be solved by the invention, when the developer D whose amount is regulated by the regulating blade 560 is transferred from the developer supply roller 550 to the developing roller 510, the rib ( (Spots such as thick streaks) may occur. Such a rib is formed when the amount of the developer D held in the groove 550a before being supplied (transferred) to the developing roller 510 is equal to or larger than the volume of the groove 550a holding the developer D. The occurrence becomes remarkable.

  This will be described in detail with reference to FIGS. 8A to 8C. 8A to 8C are conceptual diagrams for explaining an example in which ribs are generated, and are diagrams showing a state in which the developer D held in the groove 550a is transferred to the developing roller 510. FIG. 8A shows a state before transfer, FIG. 8B shows a state during transfer, and FIG. 8C shows a state after transfer.

  FIG. 8A shows a state in which the amount of the developer D held in the groove 550a before being supplied (transferred) to the developing roller 510 is equal to or larger than the volume of the groove 550a holding the developer D. It is shown. When the developer D in such a state is transferred to the developing roller 510, the developing roller 510 is caused by the action of pressure generated when the developer supplying roller 550 and the developing roller 510 are pressed against each other as shown in FIG. 8B. It is elastically deformed and bites into the groove 550a. Then, the developer D held in the groove 550a is pushed out by the developing roller 510 digging into the groove 550a, and the pushed developer D is positioned between the grooves 550a on the surface of the developer supply roller 550 (for example, FIG. Move to the position indicated by the symbol X in 8B. Therefore, a phenomenon occurs in which the developer D held in the grooves 550a adjacent to each other is connected. In this situation, when the pressure contact between the developing roller 510 and the developer supply roller 550 is released, as shown in FIG. 8C, the developer D held in the grooves 550a adjacent to each other is combined, and the developing roller 510 is brought into contact. A rib (a thick streaky pattern or the like, indicated by a symbol Y in FIG. 8C) occurs. When an image is formed by developing the latent images carried on the photoreceptors 20Y, 20M, 20C, and 20K with the developer having such ribs, the image quality is deteriorated.

  On the other hand, in the embodiment according to the present invention, the amount of the developer D held in the groove 550a before being supplied (transferred) to the developing roller 510 is smaller than the volume of the groove 550a holding the developer D. It has become. In such a case, the occurrence of ribs is suppressed.

  This will be described in detail with reference to FIGS. 9A to 9C. FIG. 9A to FIG. 9C are conceptual diagrams for explaining an example in which no rib is generated, and are diagrams illustrating a state in which the developer D held in the groove 550a is transferred to the developing roller 510. FIG. 9A shows a state before transfer, FIG. 9B shows a state during transfer, and FIG. 9C shows a state after transfer.

  FIG. 9A shows a state where the amount of the developer D held in the groove 550a before being supplied (transferred) to the developing roller 510 is smaller than the volume of the groove 550a holding the developer D. ing. When the developer D in this state is transferred to the developing roller 510, as shown in FIG. 9B, the point that the developing roller 510 bites into the groove 550a is the same as the example of FIG. 8B. However, since the amount of the developer D held in the groove 550a before being supplied (transferred) to the developing roller 510 is smaller than the volume of the groove 550a holding the developer D, the phenomenon described above, that is, The phenomenon that the developer D held in the groove 550a is pushed out and the developers D held in the adjacent grooves 550a are connected to each other does not occur. In such a situation, when the pressure contact between the developing roller 510 and the developer supply roller 550 is released, as shown in FIG. 9C, no rib is generated, and the developer D measured to an appropriate amount by the groove 550a is supplied. It is transferred to the developing roller 510. Therefore, the above-described problem, that is, when the latent image carried on the photoconductors 20Y, 20M, 20C, and 20K is developed with the developer D generated by the ribs to form an image, the image quality is deteriorated. Can be prevented appropriately.

=== Verification Method of Amount of Developer Held in Groove 550a, etc. ===
As described above, when the amount of developer held in the groove 550a before being supplied (transferred) to the developing roller 510 is smaller than the volume of the groove 550a holding the developer, the generation of ribs is suppressed. The Accordingly, it is important to accurately determine whether the amount of developer held in the groove 550a is larger or smaller than the volume of the groove 550a holding the developer. Here, an example of a method for verifying such matters will be described.

In the verification method described in the present embodiment, the volume of the groove 550a for holding the developer and the amount of the developer held in the groove 550a are separately obtained, and the two are compared, thereby holding the groove 550a. It is determined whether the amount of the developed developer is larger or smaller than the volume of the groove 550a holding the developer.
Hereinafter, the method will be described in detail by dividing into a method for obtaining the volume of the groove 550a holding the developer and a method for obtaining the amount of the developer held in the groove 550a.

<<< Method for Determining Volume of Groove 550a Holding Developer >>>
First, the cross-sectional shape of the groove 550a is measured using a laser microscope or the like, and the cross-sectional area A1 (m ² ) of the groove 550a is obtained. Next, the number of grooves N1 (1 / m) per unit length in the axial direction of the developer supply roller 550 is obtained using a stereomicroscope, a microscope, or the like. Then, by multiplying A1 and N1, the groove volume V1 = A1 × N1 per unit area on the surface of the developer supply roller 550 is calculated.

When a recess as shown in FIG. 5D or FIG. 5E is provided instead of the groove 550a, the shape of the recess is measured using a laser microscope or the like to determine the volume V2 (m ³ ) of the recess. Next, the number N2 (1 / m ² ) of depressions per unit area on the surface of the developer supply roller 550 is obtained using a stereomicroscope, a microscope, or the like. Then, by multiplying V2 and N2, the groove volume V2 = A2 × N2 per unit area on the surface of the developer supply roller 550 is calculated.

<<< Method for Obtaining Amount of Developer Held in Groove 550a >>>
When the printer 10 is operated and the peripheral speed of the developer supply roller 550 and the like is stabilized, the operation of the printer 10 is stopped. A predetermined range having an area A3 (m ² ) in a portion on the surface of the developer supply roller 550 between the contact position where the regulation blade 560 contacts and the pressure contact position where the development roller 510 is pressed. And the developer held in the groove 550a or the depression is recovered from the groove 550a or the depression provided in this range. After collecting the developer, the weight M3 (kg) of the collected developer is obtained.

  In addition, as a method of collecting the developer and determining the weight of the collected developer, the developer was transferred to a tape or the like and recovered from the difference between the tape weight before transfer and the tape weight after transfer. The method for obtaining the developer weight M3 (kg), or letting absorbent cotton or the like absorb the developer, and determine the recovered developer weight M3 (kg) from the difference between the absorbent cotton weight before the absorbent and the absorbent cotton weight after the absorbent. A desired method or the like can be used.

When the developer weight M3 (kg) is obtained, the groove 550a is inserted into the groove 550a based on the weight M3 (kg), the area A3 (m ² ), and the known developer density ρ3 (kg / m ³ ). The amount of developer held, and the developer amount V3 = M3 / (A3 × ρ3) per unit area on the surface of the developer supply roller 550 is calculated.

=== Other Embodiments ===
Although the developing device and the like according to the present invention have been described above based on the above embodiment, the above embodiment is for facilitating understanding of the present invention and does not limit the present invention. . The present invention can be changed and improved without departing from the gist thereof, and the present invention includes the equivalents thereof.

  In the above embodiment, an intermediate transfer type full-color laser beam printer has been described as an example of the image forming apparatus. However, the present invention is also applicable to a full-color laser beam printer other than the intermediate transfer type. Further, it is applicable not only to a full color laser printer but also to a monochrome laser beam printer. Further, it is applicable not only to a printer but also to various image forming apparatuses such as a copying machine and a facsimile.

  Further, the photosensitive member is not limited to a so-called photosensitive roller configured by providing a photosensitive layer on the outer peripheral surface of a cylindrical base material, and is a so-called photosensitive belt configured by providing a photosensitive layer on the surface of a belt-shaped base material. It may be.

  Further, in the above embodiment, the regulation blade 560 is arranged so that the tip thereof faces the downstream side in the rotation direction of the developer supply roller 550 and performs so-called trail regulation. For example, the tip of the developer supply roller is disposed so as to face the upstream side of the rotation direction of the developer supply roller, and so-called counter regulation may be performed.

  In the above embodiment, the developer carrier and the developer supply member are the development roller 510 and the developer supply roller 550, respectively. However, the present invention is not limited to this. For example, a belt-like development belt or developer supply belt may be used.

  In the above embodiment, the restricting means is the restricting blade 560 having elasticity, and the restricting blade 560 contacts the surface of the developer supply roller 550 and the developer on the developer supply roller 550. However, the present invention is not limited to this. For example, the following means may be used as the restricting means.

The other regulating means will be described with reference to FIGS. 10 and 11 with two examples. 10 and 11 are explanatory diagrams for explaining an example of other regulating means.
In the example of FIG. 10, the restricting means includes a rigid restricting blade 630 and a developer sucking roller 632.

  The rigid regulating blade 630 abuts on the surface of the developer supply roller 550 and regulates the amount of developer D on the developer supply roller 550. That is, the rigid regulating blade 630 scrapes off the excess developer on the developer supply roller 550. However, since the regulating blade 630 does not have elasticity, the amount is regulated by the regulating blade 630, and the groove 550a. There is a high possibility that the amount of the developer D held in (1) will be equal to or greater than the volume of the groove 550a holding the developer D (the state shown in FIG. 8A). In the example of FIG. 10, the regulation blade 630 is disposed so that the tip thereof faces the upstream side in the rotation direction of the developer supply roller, and so-called counter regulation is performed, but the invention is not limited thereto. For example, the front end of the developer supply roller 550 is arranged to face the downstream side in the rotation direction, and so-called trail regulation may be performed.

  The developer sucking roller 632 is provided with an elastic layer made of urethane rubber having a rubber hardness of about 40 degrees and a thickness of about 2 mm on the outer peripheral portion of an inner core made of metal such as iron, and its diameter. Is about 10 mm. The developer sucking roller 632 is provided on the downstream side in the rotation direction of the developer supply roller 550 when viewed from the regulating blade 630, and the developer is elastically deformed with the elastic layer serving as a pressure contact portion. It is in pressure contact with the supply roller 550. Further, the developer sucking roller 632 is rotatable about its central axis, and the central axis is above the rotation central axis of the developer supply roller 550. Further, the developer sucking roller 632 rotates in a direction (counterclockwise in FIG. 10) opposite to the rotation direction of the developer supply roller 550 (clockwise in FIG. 10).

  The developer sucking roller 632 configured as described above is rotated in a state where it is in pressure contact with the rotating developer supply roller 550, whereby the amount of the developer D held in the groove 550a is regulated by the regulating blade 630. Demonstrate the ability to absorb some. Due to the function of the developer sucking roller 632, the amount of the developer D that is equal to or larger than the volume of the groove 550a becomes smaller than the volume of the groove 550a. That is, the state of developer D shifts from the state shown in FIG. 8A to the state shown in FIG. 9A.

  The developer D sucked up by the developer sucking roller 632 is scraped off by the cleaning blade 634 that contacts the developer sucking roller 632.

  In the example of FIG. 11, the restricting means includes a rigid restricting blade 630 and an air knife 636.

  The rigid regulating blade 630 contacts the surface of the developer supply roller 550 to regulate the amount of the developer D on the developer supply roller 550, and is held in the groove 550a after the amount of the developer D is regulated. It is the same as in the example of FIG. 10 that the possibility that the amount of the developed developer D becomes higher than the volume of the groove 550a holding the developer D (the state shown in FIG. 8A) is increased. .

  On the other hand, in the example of FIG. 11, an air knife 636 is provided on the downstream side in the rotation direction of the developer supply roller 550 when viewed from the regulation blade 630 instead of the developer sucking roller 632. The air knife 636 exhibits a function of removing a part of the developer D whose amount is regulated by the regulation blade 630 and held in the groove 550a. Due to this function of the air knife 636, the amount of the developer D that is equal to or larger than the volume of the groove 550a becomes smaller than the volume of the groove 550a. That is, the state of developer D shifts from the state shown in FIG. 8A to the state shown in FIG. 9A.

  As described above, the amount of the developer D held in the groove 550a is determined by applying any of the elastic regulating blade 560, the example of FIG. 10 and the example of FIG. 11 as the regulating means. The volume of the groove 550a holding the developer D can be reduced (the state shown in FIG. 9A). However, the above embodiment is more preferable in that the configuration of the restricting means is simple.

Further, in the above embodiment, the developing roller 510 has an elastic layer, and the developer supply roller 550 is such that the surface of the developer supply roller 550 is in pressure contact with the elastic layer. However, the present invention is not limited to this. For example, the developer supply roller may supply the developer to the developing roller while the surface of the developer supplying roller is in pressure contact with the rigid layer of the developing roller.
However, the above embodiment is preferable in that the developer D is more appropriately transferred from the developer supply roller 550 to the developing roller 510.

  In the above embodiment, the hardness (about 62 degrees) of the contact portion of the regulating blade 560 with the surface of the developer supply roller 550 (about 62 degrees) is the developer supply roller 550 of the elastic layer of the development roller 510. Although the hardness is lower than the hardness (about 85 degrees) of the pressure contact portion to the surface, it is not limited to this. For example, the hardness of the contact portion may be higher than the hardness of the pressure contact portion.

  When the hardness of the contact portion is higher than the hardness of the pressure contact portion, the regulating blade does not properly bite into the groove, and accordingly, the generation of ribs is promoted. In addition, the elastic layer of the developing roller is too much bite into the groove, and an excessive amount of developer is transferred to the developing roller. When the hardness of the contact portion is lower than the hardness of the pressure contact portion, it is more desirable in that it does not have the disadvantage.

In the above embodiment, the rotation direction of the developing roller 510 is opposite to the rotation direction of the developer supply roller 550. However, the present invention is not limited to this. For example, the rotation direction of the developing roller 510 may be the same as the rotation direction of the developer supply roller 550.
When the rotation direction of the developing roller and the rotation direction of the developer supply roller are the same direction, the developing roller and the developer supply roller rotate in pressure contact with each other, so that excessive rotational resistance is generated in the pressure contact portion. When the rotation direction of the developing roller 510 and the rotation direction of the developer supply roller 550 are opposite directions, it is more desirable because it does not have the disadvantage.

In the above embodiment, the material of the developer supply roller 550 is metal. However, the material is not limited to this, and a material other than metal may be used.
However, when the material of the developer supply roller 550 is metal, the elastic blade layer of the regulating blade 560 and the development roller 510 bites into the groove 550a of the developer supply roller 550 more appropriately. The form is more desirable.

  In the above embodiment, the material of the regulating blade 560 and the material of the elastic body layer of the developing roller 510 are both rubber. However, the invention is not limited to this, and the material has elasticity. Any member can be used.

  In the above-described embodiment, the developer D is a non-volatile liquid developer that is non-volatile at normal temperature, but is not limited thereto. For example, the developer may be a low-concentration (about 1 to 2 wt%) and low-viscosity volatile liquid developer using Isopar (trademark: Exon) as a carrier at room temperature.

  The non-volatile liquid developer having non-volatility at normal temperature has a high viscosity in order to exhibit its non-volatility. When a high-viscosity liquid developer is used in the above-described developing device, the aforementioned ribs are likely to occur due to the high viscosity. Therefore, the above-described embodiment is more effective in that the above-described effect, that is, the effect of suppressing the generation of ribs and preventing the deterioration of image quality, is more effectively exhibited.

=== Configuration of Image Forming System etc. ===
Next, an image forming system according to an embodiment of the present invention will be described with reference to the drawings.

  FIG. 12 is an explanatory diagram showing an external configuration of the image forming system. The image forming system 700 includes a computer 702, a display device 704, a printer 706, an input device 708, and a reading device 710. In this embodiment, the computer 702 is housed in a mini-tower type housing, but is not limited thereto. The display device 704 is generally a CRT (Cathode Ray Tube), a plasma display, a liquid crystal display device, or the like, but is not limited thereto. As the printer 706, the printer described above is used. In this embodiment, the input device 708 uses a keyboard 708A and a mouse 708B, but is not limited thereto. In this embodiment, the reading device 710 uses a flexible disk drive device 710A and a CD-ROM drive device 710B, but is not limited to this. For example, an MO (Magneto Optical) disk drive device or DVD (Digital Versatile) Disk) etc. may be used.

  FIG. 13 is a block diagram showing a configuration of the image forming system shown in FIG. An internal memory 802 such as a RAM and an external memory such as a hard disk drive unit 804 are further provided in a housing in which the computer 702 is housed.

  In the above description, the example in which the printer 706 is connected to the computer 702, the display device 704, the input device 708, and the reading device 710 to configure the image forming system has been described. However, the present invention is not limited to this. Absent. For example, the image forming system may include a computer 702 and a printer 706, and the image forming system may not include any of the display device 704, the input device 708, and the reading device 710.

  For example, the printer 706 may have a part of the functions or mechanisms of the computer 702, the display device 704, the input device 708, and the reading device 710. As an example, the printer 706 includes an image processing unit that performs image processing, a display unit that performs various displays, a recording medium attachment / detachment unit for attaching / detaching a recording medium that records image data captured by a digital camera or the like. It is good also as a structure to have.

  The image forming system realized in this way is a system superior to the conventional system as a whole system.

1 is a diagram illustrating main components constituting an image forming apparatus according to an exemplary embodiment. FIG. 2 is a block diagram illustrating a control unit of the image forming apparatus in FIG. 1. It is sectional drawing which showed the main components of the developing unit. 5 is a perspective conceptual diagram showing the surface of a developer supply roller 550. FIG. 5A to 5E are views showing the shape of a recess provided on the surface of the developer supply roller 550. FIG. FIG. 6 is a schematic diagram illustrating trail regulation of a regulation blade 560. FIG. 6 is an enlarged conceptual diagram showing a state where a regulating blade 560 is in contact with the surface of a developer supply roller 550. 8A to 8C are conceptual diagrams for explaining an example in which ribs are generated. 9A to 9C are conceptual diagrams for explaining an example in which no rib is generated. It is explanatory drawing for demonstrating an example of another control means. It is explanatory drawing for demonstrating an example of another control means. 1 is an explanatory diagram showing an external configuration of an image forming system. It is a block diagram which shows the structure of the image forming system shown in FIG.

Explanation of symbols

10 Laser beam printer 15Y, 15M, 15C, 15K Developing unit 20Y, 20M, 20C, 20K Photoconductor 30Y, 30M, 30C, 30K Charging unit 40Y, 40M, 40C, 40K Exposure unit 50Y, 50M, 50C, 50K Developing unit 60Y , 60M, 60C, 60K Primary transfer unit 70 Intermediate transfer member 73Y, 73M, 73C, 73K Static elimination unit 75Y, 75M, 75C, 75K Photoconductor cleaning unit 76Y, 76M, 76C, 76K Photoconductor cleaning blade 80 Secondary transfer unit 100 Control unit 101 Main controller 102 Unit controller 112 Interface 113 Image memory 120 CPU
510 developing roller 530 developer accommodating portion 540 developer pumping roller 550 developer supplying roller 550a groove 560 regulating blade 560a edge portion 562 regulating blade support member 570 developing roller cleaning unit 571 developing roller cleaning blade 630 regulating blade 632 developer sucking roller 634 Cleaning blade 636 Air knife 700 Image forming system 702 Computer 704 Display device 706 Printer 708 Input device 708A Keyboard 708B Mouse 710 Reading device 710A Flexible disk drive device 710B CD-ROM drive device 802 Internal memory 804 Hard disk drive unit D Developer

Claims (6)

A developer carrier for carrying a liquid developer;
The material is a metal and has a concave portion, which is a groove provided in a spiral shape , on the surface thereof, the surface being in pressure contact with the developer carrier, and the liquid developer held in the concave portion is the developer. A rotatable developer supply roller for supplying to the carrier;
A regulating blade for regulating the amount of liquid developer on the developer supply roller in contact with the surface of the developer supply roller;
In the developing device for developing the latent image carried on the image carrier by the liquid developer carried on the developer carrier,
An elastic layer, and wherein when viewed from the regulating blade is provided on the downstream side in the rotating direction of the developer supply roller, pressed against a state in which the developer supply roller which rotates being elastically deformed, by rotating A developer sucking roller that sucks a part of the liquid developer whose amount is regulated by the regulating blade and held in the recess,
The developing device, wherein the developer sucking roller makes an amount of the liquid developer held in the recess smaller than a volume of the recess holding the liquid developer. The developing device according to claim 1,
The developing device, wherein the developer carrying member is a developer carrying roller. The developing device according to claim 2,
The developer carrying roller has an elastic part,
The developing device, wherein the developer supply roller supplies the liquid developer to the developer carrying roller with the surface pressed against the elastic portion. In the developing device according to claim 2 or 3,
The developing device according to claim 1, wherein the rotation direction of the developer carrying roller is opposite to the rotation direction of the developer supply roller. The developing device according to claim 1,
The developing device according to claim 1, wherein the liquid developer is a non-volatile liquid developer that is non-volatile at room temperature. An image carrier for carrying a latent image;
A developer carrying member for carrying the liquid developer and a concave portion, which is a metal and made of a spiral groove, are provided on the surface, and the surface is in pressure contact with the developer carrying member. , A rotatable developer supply roller for supplying the liquid developer held in the recess to the developer carrier, and liquid development on the developer supply roller in contact with the surface of the developer supply roller A developing blade for regulating the latent image carried on the image carrier by the liquid developer carried on the developer carrier, and a regulating blade for regulating the amount of the agent;
In an image forming apparatus comprising:
An elastic layer, and wherein when viewed from the regulating blade is provided on the downstream side in the rotating direction of the developer supply roller, pressed against a state in which the developer supply roller which rotates being elastically deformed, by rotating A developer sucking roller that sucks a part of the liquid developer whose amount is regulated by the regulating blade and held in the recess,
The image forming apparatus, wherein the developer sucking roller makes an amount of the liquid developer held in the concave portion smaller than a volume of the concave portion holding the liquid developer.

Images