JP6213326B2 - Developing apparatus, image forming apparatus, and developing apparatus control method - Google Patents

Description

  The present invention relates to a developing device using a developer containing toner particles and a carrier liquid, an image forming apparatus including the developing device, and a control method for the developing device.

  In recent years, various image forming apparatuses using a wet electrophotographic method capable of performing high-quality printing on demand have been proposed. In the wet electrophotographic system, image formation is performed using a developer containing a carrier liquid and toner particles.

  In such an image forming apparatus, development is performed by supplying the developer stored in the developer tank to the image carrier on which the electrostatic latent image is formed by the developer supply mechanism. The developer supply mechanism includes a supply roller to which the developer is supplied from the developer tank, a development roller, and the like. At the time of development, a thin layer of a micron unit of developer is formed on the developing roller, and the thinned developer is brought into contact with the image carrier.

  For this reason, after the developer supplied from the developer tank to the supply roller is regulated by a regulating blade or the like and the supply amount is adjusted, the developer is supplied to the development roller.

  In general, an anilox roller having a plurality of recesses on the surface is used as the supply roller. The anilox roller can control the supply amount supplied to the other member by the recess, and can appropriately control the supply amount, particularly by bringing the regulating blade into contact therewith.

  When the carrier liquid has volatility, in the standby state in which the driving of the apparatus is stopped or stopped for a long time after completion of image formation, the carrier liquid is removed from the developer carried on the anilox roller until the next image formation is started. Will volatilize. In this case, the carrier liquid stored in the recesses volatilizes, and the toner particles are clogged in the recesses of the anilox roller.

  When only the toner particles remain in the recesses, the cohesive force between the toner particles becomes strong, and even when the developer is supplied again into the recesses, the toner particles are discharged or replaced from the recesses. Can not do. For this reason, the toner particles fixed in the recesses substantially reduce the capacity of the recesses, and a desired supply amount may not be obtained.

  For example, Japanese Patent Application Laid-Open No. 2011-203719 (Patent Document 1) and Japanese Patent Application Laid-Open No. 2011-203719 disclose an image forming apparatus that can suppress the clogging of the anilox roller and suppress fluctuations in the supply amount of the developer. JP-A-2011-164257 (Patent Document 2) and JP-A-2007-57770 (Patent Document 3).

  The developing device provided in the image forming apparatus disclosed in Patent Document 1 includes a cleaning liquid supply unit that can supply a cleaning liquid to the supply roller, and supplies the cleaning liquid to the surface of the supply roller during non-image formation. Residual developer is removed and washed.

  The developing device included in the image forming apparatus disclosed in Patent Document 2 includes a coating unit that applies a liquid that is less volatile than the carrier liquid used during image formation to the supply roller, and the surface of the supply roller during non-image formation. A low-volatile liquid is applied over the front surface.

  A developing device included in the image forming apparatus disclosed in Patent Document 3 uses high-concentration toner replenished from a toner tank storing high-concentration toner and carrier liquid supplied from a carrier liquid tank storing carrier liquid. A developer concentration adjusting tank for adjusting the concentration of the developer. At the time of non-image formation, a low concentration developer lower than the toner concentration used at the time of image formation is adjusted in the developer concentration adjusting tank, and after this is applied to the supply roller, the printing operation is terminated.

JP 2011-203719 A JP 2011-164257 A JP 2007-57770 A

  However, in the configuration disclosed in Patent Document 1, in addition to the developer supply mechanism described above, a mechanism (cleaning liquid supply unit) for supplying and transporting the cleaning liquid is required, which increases the manufacturing cost and the apparatus. The configuration becomes complicated. Furthermore, a cleaning process is required, and the processing becomes complicated. In addition, the processing time required to prevent clogging is lengthened.

  In the configuration disclosed in Patent Document 2, in addition to the developer supply mechanism described above, in addition to the necessity of separately preparing a low-volatile liquid, there is an application unit for applying this to the supply roller. Necessary. For this reason, the running cost and the manufacturing cost increase and the apparatus configuration becomes complicated. In addition, there is a concern that the image quality deteriorates due to the low volatile liquid mixed in the developer.

  In the configuration disclosed in Patent Document 3, it is necessary to adjust the toner density during non-image formation, and the processing becomes complicated. In addition, since it takes time to adjust the toner concentration, the necessary processing time required to prevent clogging is lengthened. For this reason, the workability of the image forming apparatus is lowered. In addition, there is a concern that the image quality deteriorates due to the mixing of developers having different toner concentrations.

  The present invention has been made in view of the above-described problems, and an object of the present invention is to develop a toner that can easily prevent toner particles from clogging in a recess provided in a supply roller while having a simple configuration. An apparatus, an image forming apparatus, and a developing device control method are provided.

  A developing device according to a first aspect of the present invention develops an electrostatic latent image formed on an image carrier using a developer, and includes the toner particle and the volatile carrier liquid. A storage part for storing the agent; a plurality of recesses on the surface; by rotating, a supply roller to which the developer is supplied from the storage part, and rotating in a state in contact with the supply roller; The developer supplied from the transport roller by the transport roller supplied with the developer from the supply roller and rotating in a state of being in contact with the transport roller, and the developer supplied from the transport roller The developer supplied to the image carrier, and the developer supplied to the supply roller from the reservoir is supplied to the transport roller by contacting the supply roller. A regulating member that regulates the developer to a first thickness, a press-contact / separation mechanism that presses and separates the regulating member and the transport roller with respect to the supply roller, the supply roller, the transport roller, and A rotation drive mechanism for rotating the developing roller; and a controller for controlling the operation of the pressure contact / separation mechanism and the operation of the rotation drive mechanism. The control unit controls the operation of the pressure contact / separation mechanism so that the supply roller, the regulating member, and the transport roller are separated from each other before entering a standby state after the development operation is completed. A state in which the developer is supplied at a second thickness that is larger than the first thickness over the entire circumference of the supply roller by rotating the supply roller one or more times in a state of being separated from the regulating member. The operation of the rotational drive mechanism is controlled so as to stop the supply roller.

  The developing device according to the first aspect of the present invention preferably further includes a cleaning member that contacts the developing roller and removes the developer remaining on the developing roller after development. The control unit is configured so that the transport roller and the development roller are in contact with each other in a state where the control member and the transport roller are separated from the supply roller before entering a standby state after the development operation is finished. The developer remaining on the transport roller supplied to the development roller via a contact portion between the transport roller and the development roller by rotating the transport roller and the development roller, and the development roller It is preferable to control the operation of the pressure contact / separation mechanism and the operation of the rotation drive mechanism so that the developer remaining on the surface is removed by the cleaning member.

  In the developing device according to the first aspect of the present invention, when the control unit starts the developing operation from the standby state, the supply roller is in a state where the regulating member is in pressure contact with the supply roller. , And the regulating member regulates the thickness of the developer on the supply roller, and then presses the supply roller and the transport roller so that the developer whose thickness is regulated is It is preferable to control the operation of the pressure contact / separation mechanism and the operation of the rotation drive mechanism so as to be supplied to the transport roller.

  A developing device according to a second aspect of the present invention develops an electrostatic latent image formed on an image carrier using a developer, and includes a toner particle and a volatile carrier liquid. A storage portion for supplying the developer, a plurality of recesses on the surface, and a rotation roller that rotates to supply the developer from the storage portion, and a rotation in contact with the supply roller The developer is supplied from the supply roller, and the developer supplied from the supply roller is supplied to the image carrier, and the supply roller is brought into contact with the supply roller by contacting the supply roller. A regulating member that regulates the developer to a first thickness before the supplied developer is fed to the developing roller; and the regulating member and the developing roller with respect to the feeding roller It comprises a pressure / separation mechanism for pressing and spaced, a rotation drive mechanism for rotating the supply roller and the developing roller, and a control unit for controlling the operation and the operation of the rotation drive mechanism of the press-contact / separation mechanism. The control unit controls the operation of the pressure contact / separation mechanism so that the regulating member and the developing roller are separated from the supply roller before entering a standby state after completion of the developing operation. A state in which the developer is supplied at a second thickness that is larger than the first thickness over the entire circumference of the supply roller by rotating the supply roller one or more times in a state of being separated from the regulating member. The operation of the rotational drive mechanism is controlled so as to stop the supply roller.

  The developing device according to the second aspect of the present invention preferably further includes a cleaning member that contacts the developing roller and removes the developer remaining on the developing roller after development. The control unit rotates the developing roller in a state where the developing roller is separated from the supply roller before entering a standby state after the development operation is completed, thereby removing the developer remaining on the developing roller. It is preferable to control the operation of the pressure contact / separation mechanism and the operation of the rotation drive mechanism so as to be removed by the cleaning member.

  In the developing device according to the second aspect of the present invention, when the developing operation is started from the standby state, the supply roller is rotated while the regulating member is in pressure contact with the supply roller. After the thickness of the developer on the supply roller is regulated by the regulation member, the supply roller and the development roller are pressed against each other, and the developer whose thickness is regulated is supplied to the development roller. Thus, it is preferable to control the operation of the pressure contact / separation mechanism and the operation of the rotation drive mechanism.

  A developing device according to a third aspect of the present invention develops an electrostatic latent image formed on an image carrier using a developer, and includes a toner particle and a volatile carrier liquid. A storage portion for supplying the developer, a plurality of recesses on the surface, and a rotation roller that rotates to supply the developer from the storage portion, and a rotation in contact with the supply roller The developer supplied from the supply roller, and the developer supplied from the transport roller by rotating in contact with the transport roller, and the developer supplied from the transport roller. A developing roller for supplying the agent to the image carrier, a pressure contact / separation mechanism for pressing and separating the transport roller with respect to the supply roller, the supply roller, the transport roller, and Comprising a rotary drive mechanism for rotating the developing roller, and a control unit for controlling the operation and the operation of the rotation drive mechanism of the press-contact / separation mechanism. The developer supplied to the supply roller is regulated to the first thickness when passing through the contact portion between the supply roller and the transport roller. The control unit controls the operation of the pressure contact / separation mechanism so that the supply roller and the transport roller are separated from each other before entering the standby state after the development operation is completed, and the control unit is in a state of being separated from the transport roller. By rotating the supply roller one or more times, the supply roller is stopped in a state where the developer is supplied at a second thickness that is larger than the first thickness over the entire circumference of the supply roller. Thus, the operation of the rotational drive mechanism is controlled.

  The developing device according to the third aspect of the present invention preferably further includes a cleaning member that contacts the developing roller and removes the developer remaining on the developing roller after development. The controller is configured so that the transport roller and the development roller are in contact with each other in a state where the supply roller and the transport roller are in contact with each other in a state where the supply roller and the transport roller are separated from each other before entering a standby state after the development operation. By rotating the roller, the developer remaining on the transport roller supplied to the development roller via the contact portion between the transport roller and the development roller, and the residual on the development roller It is preferable to control the operation of the pressure contact / separation mechanism and the operation of the rotation drive mechanism so that the developer is removed by the cleaning member.

In the developing device according to the first to third aspects of the present invention, the volatilization rate of the carrier liquid is 0.001 g / m ² · min to 1 g / m ² · min at the usage environment temperature. Preferably there is.

  In the developing device according to the first to third aspects of the present invention, the viscosity of the developer when supplied to the supply roller is preferably 10 cSt or more and 500 cSt or less.

  The image forming apparatus according to the present invention develops the electrostatic latent image by the developing device, an image carrier on which an electrostatic latent image is formed, and the developer supplied from the developing roller to the image carrier. And a transfer unit that transfers the toner image formed on the image carrier to a recording medium.

  A developing device control method according to the present invention is a developing device control method for performing development by supplying a developer stored in a storage section to an image carrier on which an electrostatic latent image is formed. As the agent, a developer containing toner particles and a volatile carrier liquid is used, and the supply roller having a plurality of recesses on the surface rotates and contacts the developer stored in the storage unit while rotating. The film thickness of the developer supplied to the second film is adjusted to be the first film thickness during the developing operation, and the second film that is thicker than the first film thickness before entering the standby state after the developing operation is completed. Adjust to be thick.

  In the control method of the developing device according to the present invention, when the developing operation is started from the standby state, the film thickness of the developer supplied to the supply roller is regulated, and then the image is carried from the supply roller. The developer is preferably supplied toward the body.

  According to the present invention, it is possible to provide a developing device, an image forming device, and a developing device control method that can easily suppress clogging of toner particles in a recess provided in a supply roller while having a simple configuration. .

1 is a schematic diagram illustrating an overall configuration of an image forming apparatus according to Embodiment 1 of the present invention. It is a block diagram which shows the control structure of the developing device which concerns on Embodiment 1 of this invention. It is a flowchart which shows the control method of the developing device which concerns on Embodiment 1 of this invention. It is a schematic diagram which shows the operation | movement which supplies a developing agent to a supply roller in a standby state. FIG. 6 is a flowchart showing an operation of the developing device when starting a developing operation in the developing device control method according to the first embodiment of the present invention. FIG. 6 is a schematic diagram illustrating a developing device provided in an image forming apparatus according to a second embodiment of the present invention. It is a flowchart which shows the control method of the developing device which concerns on Embodiment 2 of this invention. FIG. 10 is a flowchart showing an operation of the developing device when starting a developing operation in the developing device control method according to the second embodiment of the present invention. It is a schematic diagram which shows the developing device with which the image forming apparatus which concerns on Embodiment 3 of this invention is equipped. It is a block diagram which shows the control structure of the developing device which concerns on Embodiment 3 of this invention. It is a flowchart which shows the control method of the developing device which concerns on Embodiment 3 of this invention.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the following embodiments, the same or common parts are denoted by the same reference numerals in the drawings, and description thereof will not be repeated.

(Embodiment 1)
(Overall configuration and operation of image forming apparatus)
FIG. 1 is a diagram illustrating an overall configuration of an image forming apparatus according to the present embodiment. FIG. 2 is a block diagram showing a control configuration of the developing device according to the present embodiment. With reference to FIG. 1 and FIG. 2, the overall configuration of image forming apparatus 100 according to the present embodiment will be described.

  As shown in FIG. 1, an image forming apparatus 100 according to this embodiment includes an image carrier 1 as an image carrier, a charging device 2, an exposure device 3, a developing device 4, and an intermediate as a transfer unit. The image forming apparatus includes a transfer member 5 and a secondary transfer member 6, an image carrier cleaning device 7, and an intermediate transfer member cleaning device 8.

  The image carrier 1 has a cylindrical shape with an image carrier layer (not shown) formed on the surface thereof. The image carrier 1 is rotationally driven in the direction of arrow A in FIG. On the outer periphery of the image carrier 1, a charging device 2, an exposure device 3, a developing device 4, an intermediate transfer member 5, and an image carrier cleaning device 7 are sequentially arranged along the rotation direction (A direction) of the image carrier 1. Has been.

  The charging device 2 charges the surface of the image carrier 1 to a predetermined potential. The exposure device 3 irradiates the surface of the image carrier 1 with light and lowers the charge level in the irradiated area to form an electrostatic latent image. The developing device 4 develops the electrostatic latent image formed on the image carrier 1. Specifically, a developer is supplied to the developing area of the image carrier 1 and toner particles contained in the developer are supplied to the electrostatic latent image on the surface of the image carrier 1 to form a toner image.

  In the developing process, a developing bias voltage is applied from a power source (not shown) to a developing roller 9 of the developing device 4 described later. The toner particles in the developer are electrostatically attracted to the electrostatic latent image portion of the image carrier 1 in accordance with the electric field generated by the balance between the potential of the electrostatic latent image on the image carrier 1 and the potential of the developing roller 9. The electrostatic latent image on the carrier 1 is developed.

  The intermediate transfer member 5 is disposed so as to face the image carrier 1 and rotates in the direction of arrow B in the drawing while being in contact with the image carrier 1. Primary transfer from the image carrier 1 to the intermediate transfer member 5 is performed at the nip portion between the intermediate transfer member 5 and the image carrier 1.

  In the primary transfer process, a transfer bias voltage is applied to the intermediate transfer member 5 from a power source (not shown). As a result, an electric field is formed between the intermediate transfer member 5 and the image carrier 1 at the primary transfer position, and the toner image on the image carrier 1 is electrostatically attracted to the intermediate transfer member 5. As a result, the toner image on the image carrier 1 is transferred onto the intermediate transfer member 5.

  When the toner image on the image carrier 1 is transferred to the intermediate transfer member 5, the image carrier cleaning device 7 removes the residual toner image on the image carrier 1, and the next image formation is performed. An eraser lamp 10 is installed between the image carrier cleaning device 7 and the charging device 2 as necessary.

  The intermediate transfer member 5 and the secondary transfer member 6 are arranged so as to face each other with a recording medium 11 as a recording material interposed therebetween, and rotate in contact with each other via the recording medium 11. Secondary transfer from the intermediate transfer member 5 to the recording medium 11 is performed at the nip portion between the intermediate transfer member 5 and the secondary transfer member 6. The recording medium 11 is conveyed to the secondary transfer position in the direction of arrow C in the drawing in accordance with the secondary transfer timing.

  In the secondary transfer process, a transfer bias voltage is applied to the secondary transfer member 6 from a power source (not shown). As a result, an electric field is formed between the intermediate transfer member 5 and the secondary transfer member 6, and onto the recording medium 11 that has passed between the intermediate transfer member 5 and the secondary transfer member 6. The toner image is electrostatically attracted and transferred.

  When the toner image is transferred onto the recording medium 11, the intermediate transfer member cleaning device 8 removes the residual toner image on the intermediate transfer member 5, and the next primary transfer is performed. Thereafter, the recording medium 11 is conveyed to a fixing device (not shown), and the toner particles on the recording medium 11 are heated and melted to fix the toner particles on the recording medium 11.

  FIG. 1 shows a monochromatic image forming apparatus 100 having only one set of the image carrier 1 and the developing device 4, but a total of four sets of both the image carrier 1 and the developing device 4 are prepared. For a color image forming apparatus in which CMYK (Cyan, Magenta, Yellow, and Black) images are formed and superimposed on the recording medium 11, respectively. The present invention is also applicable. The present invention can also be applied to a direct transfer method in which the intermediate transfer member 5 is omitted and a toner image is directly transferred from the image carrier 1 to a recording medium. In addition, the conventional electrophotographic process technologies can be combined with any configuration according to the purpose of the image forming apparatus.

(Developer composition)
The developer used for development contains a carrier liquid which is a solvent and colored toner particles. As the carrier liquid, an insulating solvent that is volatile in the environment where the image forming apparatus is used is used.

  The volume average particle diameter of the toner particles is suitably in the range of 0.1 μm to 5 μm. When the average particle diameter of the toner particles is less than 0.1 μm, the developability is greatly lowered. On the other hand, when the average particle diameter exceeds 5 μm, the quality of an image including dots and solids is lowered. The volume average particle diameter of the toner particles is more preferably in the range of 1 μm to 2 μm. When the average particle diameter of the toner particles is 1 μm or more, the cleaning property is further improved, and when the average particle diameter of the toner particles is 2 μm or less, the uniformity of the solid portion in the image is further stabilized.

  The ratio of the mass of the toner particles to the mass of the developer is preferably 10% or more and 50% or less. When the ratio of the mass of the toner particles to the mass of the developer is 10% or more, the toner particles are less likely to settle, and the toner particles have high stability over time during long-term storage. Therefore, the amount of developer necessary for obtaining a high image density can be reduced. Accordingly, it is not necessary to dry a large amount of carrier liquid when fixing toner particles, and it is possible to prevent a large amount of vapor from being generated from the carrier liquid. When the ratio of the mass of the toner particles to the mass of the developer is 50% or less, the viscosity of the developer becomes an appropriate value, and the handling at the time of manufacture becomes good. The developer viscosity and carrier liquid volatility will be described later.

(Details of development device configuration and development process)
As shown in FIG. 1, the developing device 4 includes a developer tank 13 as a storage unit, a supply roller 14, a transport roller 16, a developing roller 9, a regulating blade 15 as a regulating member, a toner charging device 17, a static eliminating device 19, and A cleaning member 18 is included.

  The developer tank 13 stores the developer 12 described above. The supply roller 14 is provided so that a part thereof is immersed in the developer 12 in the developer tank 13. The supply roller 14 has a plurality of concave portions on the surface, and draws the developer 12 from the developer tank 13 by rotating. As a result, the developer 12 is supplied to the supply roller 14. The supply roller 14 rotates in the direction of arrow D in the figure.

  An anilox roller can be used as the supply roller 14. An anilox roller is obtained by regularly processing concave portions such as thin grooves and small holes called cells on the surface of a metal cylinder. Developer can enter these recesses, and a developer corresponding to the capacity of the recesses can be supplied. The capacity of the recess is defined by the number of lines, and generally the capacity decreases as the number of lines increases.

  The cell shape of the anilox roller is not particularly limited, and examples thereof include a spiral shape, a lattice shape, a diamond shape, and a honeycomb shape. Moreover, the material of the above-mentioned metal cylinder is not specifically limited, The stainless steel cylinder generally used may be used and another metal may be used. Also, the number of lines is not particularly limited, but if it is less than 100 lpi, the pattern of the recesses appears as image noise, which is not preferable.

  The regulation blade 15 contacts the supply roller 14 and regulates the developer 12 to the first thickness before the developer 12 supplied from the developer tank 13 to the supply roller 14 is supplied to the transport roller 16. .

  The transport roller 16 is rotated in the direction E in the drawing while being in contact with the supply roller 14, whereby the developer 12 whose thickness is regulated is supplied from the supply roller 14. The transport roller 16 rotates so that the rotation direction at the contact portion (nip portion) with the developing roller 9 is opposite to the rotation direction of the developing roller 9, and the developer 12 supplied from the supply roller 14. In that direction. As the conveyance roller 16, a rubber roller made of urethane or NBR can be adopted.

  The developer roller 9 is supplied from the transport roller 16 by rotating in the direction F in the drawing while being in contact with the transport roller 16. On the developing roller 9, a thin layer of the developer 12 adjusted to have a uniform thickness in the longitudinal direction is formed. The developing roller 9 supplies the developer 12 supplied from the transport roller 16 to the image carrier.

  In the vicinity of the developing roller 9, the transport roller 16, the toner charging device 17, the image carrier 1, the charge eliminating device 19, and the cleaning member 18 are arranged in this order along the rotation direction of the developing roller 9.

  The toner particles contained in the developer 12 supplied onto the developing roller 9 are charged to either positive polarity or negative polarity by the toner charging device 17. The toner charging device 17 can change the charge amount applied to the toner particles according to the applied voltage. As the toner charging device 17, a corotron can be adopted as shown in FIG. 1, but the present invention is not limited to this, and a scorotron, a discharge roller or the like may be adopted.

  The developer 12 charged with the toner particles moves to a developing nip portion that is a portion where the image carrier 1 and the developing roller 9 are opposed to each other as the developing roller 9 rotates. In the developing nip portion, the toner thin layer formed on the developing roller 9 contacts the image carrier 1 to develop the electrostatic latent image on the image carrier 1.

  The toner particles contained in the developer 12 that are not used for development and remain on the developing roller 9 are neutralized by the neutralization device 19. The developer 12 containing the removed toner particles is removed from the developing roller 9 by the cleaning member 18.

  In addition, the relative rotation direction of the supply roller 14, the conveyance roller 16, and the developing roller 9 may be different from the above-described rotation direction.

(Developer control structure)
As shown in FIG. 2, the image forming apparatus 100 further includes a control unit 40, a rotation drive mechanism 50, a press contact / separation mechanism 60, a rotation detection unit 70, a memory 80, and an operation panel 90. The control unit 40 controls the operations of the rotation drive mechanism 50 and the pressure contact / separation mechanism 60 based on information from the rotation detection unit 70, the memory 80, and the operation panel 90.

  The operation panel 90 includes a display unit that notifies the user of various types of information and an input unit that receives various types of user operations. More specifically, the operation panel 90 includes various input key groups including a numeric keypad and a touch sensor as a function of the input unit, and a liquid crystal display unit integrated with the touch sensor as a function of the display unit, and Includes various indicators such as LEDs (Light Emitting Diodes).

  The memory 80 is a storage medium in which programs for executing various processes are stored in advance, and the control unit 40 controls the image forming apparatus 100 based on information input from the memory 80.

  The rotation detection unit 70 detects the rotation speed and rotation direction of the supply roller 14 and the developing roller 9. The rotation detection unit 70 includes a supply roller rotation detection unit 71 and a developing roller rotation detection unit 72. The supply roller-rotation detection unit 71 detects the rotation speed and rotation direction of the supply roller 14 and outputs detection information to the control unit 40. The development roller rotation detection unit 72 detects the number of rotations and the rotation direction of the development roller and outputs detection information to the control unit 40.

  Based on these detection information, the control unit 40 controls operations of a supply roller rotation motor 51 and a development roller rotation motor 52 described later, so that the rotation operations of the supply roller 14 and the development roller 9 are appropriately controlled.

  The rotation driving mechanism 50 rotates the supply roller 14, the transport roller 16, and the developing roller 9 by driving according to an instruction from the control unit 40. The rotation drive mechanism 50 includes a supply roller rotation motor 51 and a developing roller rotation motor 52. The supply roller 14 is rotated by driving the supply roller rotation motor 51. By driving the developing roller rotating motor 52, the developing roller 9 rotates.

  The pressure contact / separation mechanism 60 is driven according to an instruction from the control unit 40 to press and separate the regulating blade 15 and the transport roller 16 from the supply roller 14. The pressure contact / separation mechanism 60 includes a supply roller pressure contact / separation mechanism 61 and a regulating blade pressure contact / separation mechanism 62.

  The supply roller press-contact / separation mechanism 61 includes a cam or a spring. The control unit 40 controls the operation of the supply roller pressure contact / separation mechanism 61, and is urged so that the supply roller 14 and the transport roller 16 are spaced apart from each other (separated state) and are pressed against each other. Switch to the placed state (pressure contact state).

  In the pressure contact state, a nip portion (contact portion) is formed between the supply roller 14 and the transport roller 16. In this state, the supply roller 14 is rotated at a predetermined peripheral speed by the supply roller rotation motor 51, and the transport roller 16 receives the pressure frictional force from the supply roller 14 via the nip portion. Thereby, the conveyance roller 16 is driven and rotated. On the other hand, in the separated state, only the supply roller 14 rotates at a predetermined peripheral speed.

  The regulating blade pressure contact / separation mechanism 62 includes a spring and the like. The control unit 40 controls the regulating blade pressure contact / separation mechanism 62, and is arranged so that the supply roller 14 and the regulation blade 15 are arranged to be separated from each other (separated state) and urged to be brought into pressure contact with each other. Switch to the pressed state (pressure contact state).

  In the pressure contact state, when the supply roller 14 rotates, excess developer 12 supplied from the developer tank 13 is scraped off by the regulating blade 15. Thereby, the amount of the developer 12 supplied to the transport roller 16 is adjusted. The thickness of the developer 12 that has passed through the regulating blade 15 is defined as the first thickness.

  On the other hand, in the separated state, the developer 12 is not scraped off even when the supply roller 14 rotates. For this reason, the developer 12 having the second thickness larger than the first thickness is supplied over the entire circumference of the supply roller 14 by rotating the supply roller 14 at least once.

(Developer control method)
FIG. 3 is a flowchart showing a control method of the developing device according to the present embodiment. FIG. 4 is a schematic diagram illustrating an operation of supplying the developer to the supply roller in the standby state. With reference to FIG. 3 and FIG. 4, the control method of the developing device will be described.

  As shown in FIG. 3, when image formation (development operation) is started from the standby state, in step (S10), the control unit 40 performs image stabilization such as setting of exposure conditions, charging conditions, and development conditions. Start the conversion process. Next, in step (S <b> 20), the control unit 40 controls the operation of the press contact / separation mechanism 60 to press the transport roller 16 and the regulating blade 15 against the supply roller 14.

  In addition, a process (S10) and a process (S20) may be performed simultaneously, and a process (S20) may be performed before a process (S10). Detailed operation in the step (20) will be described later with reference to FIG.

  Subsequently, when the image stabilization process and the operation of step (S20) are completed, image formation is started in step (S30). In step (S40), the control unit 40 determines whether or not the print job is completed. Here, “the state in which the print job has been completed” refers to “a state in which image formation has been completed on the last recording medium 11 of the print job”. The developing operation has also been completed.

  If image formation has been completed on the last recording medium 11 (step S7; Yes), the control unit executes step (S50). On the other hand, when the print job is not completed and the recording medium 11 to be processed remains (step S40; No), the control unit 40 continues image formation until the print job is completed.

  Next, as shown in FIGS. 3 and 4, in step (S <b> 50), the control unit 40 controls the operation of the press contact / separation mechanism 60 to move the transport roller 16 and the regulating blade 15 to the supply roller 14. Separate. Subsequently, in step (S <b> 60), the control unit 40 controls the operation of the rotation drive mechanism 50 to rotate the supply roller 14 while being separated from the transport roller 16 and the regulating blade 15.

  In the step (S70), the control unit 40 determines whether or not the supply roller 14 has rotated a predetermined number of times or more based on information from the supply roller rotation detection unit 71. When the number of rotations of the supply roller 14 is less than the predetermined number (step S70: NO), the control unit 40 rotates the supply roller 14 until the number of rotations reaches the predetermined number.

  If the number of rotations of the supply roller 14 is equal to or greater than the predetermined number (step S70: YES), the step (S80) is performed. Here, the predetermined number of times is at least once.

  Note that the rotation direction of the supply roller 14 may be the same as that during image formation, or may be rotated in reverse. Further, as long as the developer 12 can be supplied over the entire circumference of the supply roller 14, the rotation direction may be changed in the middle. At this time, normal rotation and inversion may be repeated.

  In the step (S70), since the supply roller 14 rotates while being separated from the transport roller 16 and the regulating blade 15, the excess developer supplied from the developer tank 13 to the supply roller 14 is maintained on the supply roller 14. Is done. For this reason, by making the supply roller 14 at least one rotation or more, the developer 12 having the second thickness that is thicker than the first thickness of the developer 12 regulated by the regulation blade 15 is all of the supply roller 14. It is supplied over the circumference.

  Next, in the step (S80), the control unit 40 stops the operation of the rotation drive mechanism 50 and stops the rotation of the supply roller 14. As a result, the image forming apparatus enters a standby state. In this state, a thick film developer 12 is applied to the surface of the supply roller 14. When the developer 12 is applied to a thick film, the carrier liquid evaporates from the surface side of the developer 12 that is in direct contact with the atmosphere, but the carrier liquid is located in the lower layer side and is accommodated in the recess of the supply roller 14. Does not volatilize immediately.

  Volatilization of the carrier liquid from the developer 12 is volatilized at a constant rate up to a predetermined toner concentration (Tc) ratio (ratio of toner in the total developer including the carrier liquid and the toner). In the high Tc ratio region where the Tc ratio is as high as 80% or more, the ratio of the toner exposed on the surface of the developer 12 is high, so the area where the carrier liquid is in contact with the air is reduced, and the carrier liquid per unit area of the roller surface is reduced. The volatilization rate is extremely reduced.

  When the developer 12 on the supply roller 14 is a thick film, when the carrier liquid on the surface side of the developer 12 volatilizes and the Tc ratio of the portion increases, the volatilization rate from the surface of the developer 12 decreases. The portion where the Tc concentration is increased exhibits an effect like a film that suppresses the volatilization of the carrier liquid. For this reason, the developer 12 in the supply roller recess is kept in a state where the carrier liquid is relatively large for a long period of time. As a result, volatilization of the carrier liquid in the recess can be suppressed and toner particles can be prevented from clogging in the recess.

  In the state where the supply roller 14 is stopped, the thickness of the developer carried on the supply roller 14 is preferably 50 μm or more. In this case, the effect of the above-mentioned film is more remarkably exhibited, and the carrier liquid can be prevented from volatilizing in a short period.

(Preventing drying of the developer on the transport roller and the developing roller)
While the steps (S50) to (S80) are being performed, the developer remaining on the developing roller 9 and the developer remaining on the conveying roller 16 are removed by the cleaning member 18.

  Specifically, the control unit 40 controls the rotation driving mechanism 50 in a state where the transport roller 16 is separated from the supply roller 14 to rotate the developing roller 9. In this state, the developer 12 is not supplied from the supply roller 14 to the transport roller 16. In this state, since the transport roller 16 and the developing roller 9 are in contact with each other, the transport roller 16 receives a pressure frictional force from the developing roller 9 through the contact portion. Thereby, the conveyance roller 16 is driven and rotated.

  In this way, in a state where the regulating blade 15 and the transport roller 16 are separated from the supply roller 14, the transport roller and the developing roller rotate while the transport roller 16 and the developing roller 9 are in contact with each other. While the developer remaining on the transport roller 16 is supplied to the developing roller 9 through the contact portion with the roller, the developer on the developing roller 9 is removed by the cleaning member 18.

  Therefore, by rotating the developing roller 9 for a predetermined time, the developer remaining on the transport roller 16 and the developer remaining on the developing roller 9 at the end of image formation can be removed by the cleaning member 18. .

  As a result, the drying of the developer 12 on the developing roller 9 and the conveying roller 16 can be prevented. Since the toner particles aggregated by the drying of the developer 12 can be prevented from entering the cleaning member 18, deterioration of the edge of the cleaning member 18 (a phenomenon in which the edge is partially chipped) can be prevented.

(Operation of the developing device when starting the developing operation)
When returning from the standby state with the thick film developer 12 applied on the supply roller 14 as described above, the excess developer 12 is not supplied from the supply roller 14 to the transport roller 16. It is preferable to make it. For this reason, when starting the developing operation, it is preferable to operate the developing device 4 as follows.

  FIG. 5 is a flowchart showing the operation of the developing device when starting the developing operation in the developing device control method according to the present embodiment. With reference to FIG. 5, the operation of the developing device when the developing operation is started will be described.

  As shown in FIG. 5, in step (S <b> 20), first, in step (S <b> 21), the control unit 40 controls the operation of the press contact / separation mechanism 60 to press the regulating blade 15 against the supply roller 14. Let In this state, the supply roller 14 is not in contact with the transport roller 16. Subsequently, in the step (S22), the control unit 40 controls the operation of the rotation drive mechanism 50 to rotate the supply roller 14.

  Next, in step (S23), the control unit 40 determines whether the supply roller 14 has rotated a predetermined number of times or more based on information from the supply roller rotation detection unit 71. When the number of rotations of the supply roller 14 is less than the predetermined number (step S23: NO), the control unit 40 rotates the supply roller 14 until the number of rotations reaches the predetermined number.

  If the number of rotations of the supply roller 14 is equal to or greater than the predetermined number (step S23: YES), the step (S14) is performed. Here, the predetermined number of times is preferably at least once, but as long as the film thickness of the developer 12 on the supply roller 14 can be regulated and the developer 12 with the regulated film thickness can be supplied to the transport roller 16. It may be less than one rotation such as half rotation.

  By rotating the supply roller 14 in a state where the regulating blade 15 is in pressure contact with the supply roller 14, excess developer 12 is scraped off and the thickness of the developer 12 in a thick film state is regulated.

  Subsequently, in the step (S24), the control unit 40 controls the operation of the pressure contact / separation mechanism 60 and the operation of the rotation drive mechanism 50 so that the developer 12 whose thickness is regulated by the regulation blade 15 is supplied to the supply roller. After passing the position where 14 and conveyance roller 16 will contact, supply roller 14 and conveyance roller are pressed. As a result, the developer 12 whose supply amount has been adjusted is supplied to the image carrier 1 via the conveying roller 16 and the developing roller 9.

  As described above, when image formation is started from the standby state, the developer 12 supplied from the supply roller 14 toward the image carrier 1 is supplied after the film thickness of the developer 12 supplied to the supply roller 14 is regulated. It is preferable to do.

  In this case, since the developer 12 on the supply roller 14 applied to the thick film is returned to the developer tank 13 by the regulating blade 15, it is possible to prevent wasteful discharge of the developer 12. Further, since the excess developer 12 is not supplied to the developing roller 9, it is possible to prevent a large amount of developer 12 from being removed at once by the cleaning member 18. Thereby, deterioration of the cleaning member 18 can be prevented.

(Velocity rate of carrier liquid)
The volatilization rate of the carrier liquid used in the developing device of the present embodiment is, for example, 0.001 [g / (m) under an environmental temperature (about 10 ° C. to about 30 ° C.) where the image forming apparatus is used or installed. ² · min)] to 1 [g / (m ² · min)].

When the volatilization rate of the carrier liquid is 0.001 [g / (m ² · min)] or more, there is a considerable amount of volatilization of the carrier liquid in the standby state (apparatus halt state or apparatus halt state). The effect of preventing clogging of the supplied supply roller appears more remarkably. When the volatilization rate of the carrier liquid is 1 [g / (m ² · min)] or less, for example, the carrier liquid is volatilized extremely in a short time (less than 1 hour) such as switching work between JOBs. Therefore, the effect of preventing the clogging of the supply roller described above appears more remarkably.

The volatilization rate of the carrier liquid is, for example, by applying the carrier liquid with a uniform thickness on a smooth sheet formed of resin using a bar coater or the like, and changing the weight per unit area at regular intervals. It can be measured by measuring. Since the volatilization amount of the carrier liquid alone is proportional to the surface area exposed to the outside regardless of the applied film thickness, the change in weight per unit area decreases at a constant rate with respect to time. Thereby, the volatilization amount per unit area and unit time can be calculated. Therefore, the unit of the volatilization rate of the carrier liquid can be expressed by, for example, [g / (m ² · min)] as described above.

(Viscosity of developer)
The viscosity of the developer 12 used in the developing device of the present embodiment is preferably 10 cSt or more and 500 cst or less, for example, when supplied to the supply roller 14.

  When the viscosity of the developer 12 is low, the amount of the developer 12 pumped from the developer tank 13 by the supply roller 14 is reduced. In addition, excessive developer 12 may flow down from the supply roller 14 against gravity. In such a case, the developer 12 covering the supply roller 14 becomes thin.

  When the concentration of the developer 12 is 10 cSt or more, since the thickness of the developer 12 covering the supply roller 14 can be 50 μm or more, the carrier liquid positioned below the surface of the developer 12 is volatilized. This can be further suppressed. Thereby, the effect which can prevent the clogging of the supply roller mentioned above appears more notably.

  As the viscosity of the developer 12 increases, the amount of the developer 12 pumped up from the developer tank 13 by the supply roller 14 increases. Further, since the force to stay on the supply roller 14 is increased, the thickness of the developer 12 covering the supply roller 14 is increased.

  If the viscosity of the developer 12 is too high, the developer 12 supplied to the developing roller 9 cannot be leveled, and the surface pattern of the supply roller 14 may appear in the image as image noise during image formation.

  For this reason, by making the density | concentration of the developer 12 500 cSt or less, it is possible to exert the effect of preventing the clogging of the supply roller described above while further suppressing the influence on the image quality.

  The thickness of the developer covering the supply roller 14 is 30 minutes until the developer 12 on the surface of the supply roller 14 is stabilized by rotating the supply roller 14 with the regulating blade 15 being separated from the supply roller 14. After waiting, the measurement was made on the peripheral surface perpendicular to the roller surface. The amount of developer per unit area is calculated from the amount of developer obtained by wiping off the developer 12 at the measurement position, and the value obtained by dividing this by the specific gravity of the developer 12 is defined as the film thickness.

  The viscosity of the developer 12 is appropriately determined by changing the ratio of the toner in the developer, the particle size and particle size distribution of the toner, the type of toner, the type of carrier liquid, the presence / absence of addition of a dispersant, and the addition amount Can be adjusted.

  As described above, by using the developing device 4 according to the present embodiment, the image forming apparatus 100 including the developing device 4, and the control method of the developing device 4, the regulation blade 15 before entering the standby state after the image formation is completed. The supply roller 14 is stopped in a state where the developer 12 having the second thickness that is thicker than the first thickness of the developer controlled by the supply roller 14 is supplied over the entire circumference of the supply roller 14. It is possible to prevent the toner particles from being clogged in the concave portion of the roller 14.

  Since the supply roller 14 can be prevented from being clogged by simply rotating the supply roller 14 away from the regulating blade 15 and the transport roller 16, the operation can be easily performed. Further, it is not necessary to separately provide a mechanism for supplying a low-volatile liquid or a cleaning liquid, and the configuration of the apparatus can be simplified.

  Since it is not necessary to use a liquid with low volatility or a cleaning liquid, it is possible to prevent the image quality from being deteriorated by mixing these liquids into the developer. When clogging occurs, the user needs to clean the supply roller, so that the burden on the user can be greatly reduced.

  Further, since only the supply roller 14 is rotated, the processing time can be greatly shortened. For this reason, even when the interval from the standby state to the return state (the state where the next image formation is started) is short, it is possible to respond quickly. Thereby, it is possible to prevent the printable time from being reduced.

(Embodiment 2)
FIG. 6 is a schematic diagram showing a developing device provided in the image forming apparatus according to the present embodiment. The image forming apparatus according to the present embodiment will be described with reference to FIG.

  As shown in FIG. 6, the image forming apparatus according to the present embodiment is different from the image forming apparatus 100 according to the first embodiment in the configuration of the developing device 4A, and the other configurations are almost the same. It is. Accordingly, the control method of the developing device 4A is also different.

  As shown in FIG. 6, the developing device 4 </ b> A is different from the developing device 4 according to the first embodiment in that it does not include the transport roller 16 between the developing roller 9 and the supply roller 14. The developing roller 9 rotates while being in contact with the supply roller 14, whereby the developer 12 is supplied from the supply roller 14 and supplies the developer 12 supplied from the supply roller 14 to the image carrier 1. The control configuration of the developing device 4A is the same as that of the developing device 4 according to the first embodiment.

(Developer control method)
FIG. 7 is a flowchart showing a control method of the developing device according to the present embodiment. A control method of the developing device 4A will be described with reference to FIG.

  As shown in FIG. 7, in the step (S10), the same processing as in the first embodiment described above is performed. Next, in step (S <b> 20 </ b> A), the control unit 40 controls the operation of the press contact / separation mechanism 60 to press the developing roller 9 and the regulating blade 15 against the supply roller 14. The detailed operation will be described later with reference to FIG.

  Subsequently, in the steps (S30) to (S40), the same processing as in the first embodiment described above is performed.

  Next, in the step (S <b> 50 </ b> A), the control unit 40 controls the operation of the press contact / separation mechanism 60 to separate the developing roller 9 and the regulating blade 15 from the supply roller 14. Subsequently, in step (S <b> 60), the control unit 40 controls the operation of the rotation driving mechanism 50 to rotate the supply roller 14 while being separated from the developing roller 9 and the regulating blade 15.

  Subsequently, in the steps (S70) to (S80), the same processing as in the first embodiment described above is performed. Thus, the supply roller in a state where the developer 12 having the second thickness larger than the first thickness of the developer 12 regulated by the regulation blade 15 is supplied over the entire circumference of the supply roller 14. 14 stops.

(Preventing drying of the developer on the transport roller and the developing roller)
While the process (S50) to the process (S80) are performed, the developer 12 remaining on the developing roller 9 is removed by the cleaning member 18.

  Specifically, the control unit 40 controls the rotation driving mechanism 50 in a state where the developing roller 9 is separated from the supply roller 14 to rotate the developing roller 9. In this state, the developer 12 is not supplied from the supply roller 14 to the developing roller 9.

  For this reason, by rotating the developing roller 9 for a predetermined time, the developer 12 remaining on the developing roller 9 at the end of image formation can be removed by the cleaning member 18.

  As a result, drying of the developer 12 on the developing roller 9 can be prevented. Since the toner particles aggregated by the drying of the developer 12 can be prevented from entering the cleaning member 18, deterioration of the edge of the cleaning member 18 (a phenomenon in which the edge is partially chipped) can be prevented.

(Operation of the developing device when starting the developing operation)
FIG. 8 is a flowchart showing the operation of the developing device when starting the developing operation in the control method of the developing device according to the present embodiment. With reference to FIG. 8, the operation of the developing device when starting the developing operation will be described.

  As shown in FIG. 8, in the step (S20A), the same processing as in the first embodiment described above is performed from the step (S21) to the step (S23). Subsequently, in the step (S24A), the control unit 40 controls the operation of the pressure contact / separation mechanism 60 and the operation of the rotation drive mechanism 50, so that the developer 12 whose thickness is regulated by the regulation blade 15 is supplied to the supply roller. After passing through a position where 14 and the developing roller 9 come into contact, the supply roller 14 and the developing roller 9 are pressed against each other.

  Accordingly, also in the present embodiment, when image formation is started from the standby state, the film thickness of the developer 12 supplied to the supply roller 14 is regulated, and then the supply roller 14 faces the image carrier 1. Developer 12 can be supplied.

  As described above, by using the developing device 4A according to the present embodiment, the image forming apparatus including the developing device, and the control method of the developing device 4A, the control blade 15 uses the control blade 15 before entering the standby state after the image formation is completed. The supply roller 14 is stopped by stopping the supply roller 14 in a state where the developer having the second thickness larger than the first thickness of the regulated developer is supplied over the entire circumference of the supply roller 14. It is possible to prevent toner particles from clogging in the recesses. As described above, also in the present embodiment, substantially the same effect as in the first embodiment can be obtained.

(Embodiment 3)
FIG. 9 is a schematic diagram showing a developing device provided in the image forming apparatus according to the present embodiment. FIG. 10 is a block diagram showing a control configuration of the developing device according to the present embodiment. The image forming apparatus according to the present embodiment will be described with reference to FIGS.

  As shown in FIGS. 9 and 10, the image forming apparatus according to the present embodiment differs from the image forming apparatus 100 according to the first embodiment in the configuration and control configuration of the developing device 4B. The configuration is substantially the same. Accordingly, the control method of the developing device 4B is also different.

  The developing device 4B is different from the developing device 4 according to the first embodiment in that it does not include a regulating blade and a regulating blade pressure contact / separation mechanism, and the other configurations are substantially the same. is there. In this case, the developer supplied to the supply roller 14 is regulated to the first thickness when passing through the contact portion between the supply roller 14 and the transport roller 16.

(Developer control method)
FIG. 11 is a flowchart showing a control method of the developing device according to the present embodiment. A control method of the developing device 4B will be described with reference to FIG.

  As shown in FIG. 11, in the step (S10), the same processing as in the first embodiment described above is performed. Next, in the step (S <b> 20 </ b> B), the control unit 40 controls the operation of the press contact / separation mechanism 60 to press the transport roller 16 against the supply roller 14.

  Subsequently, in the steps (S30) to (S40), the same processing as in the first embodiment described above is performed.

  Next, in the step (S <b> 50 </ b> B), the control unit 40 controls the operation of the press contact / separation mechanism 60 to separate the transport roller 16 from the supply roller 14. Subsequently, in step (S <b> 60), the control unit 40 controls the operation of the rotation driving mechanism 50 to rotate the supply roller 14 while being separated from the transport roller 16.

  Subsequently, in the steps (S70) to (S80), the same processing as in the first embodiment described above is performed. As a result, the supply roller in a state where the developer 12 having the second thickness larger than the first thickness of the developer 12 regulated by the transport roller 16 is supplied over the entire circumference of the supply roller 14. 14 stops.

(Preventing drying of the developer on the transport roller and the developing roller)
While the steps (S50) to (S80) are being performed, the developer remaining on the developing roller 9 and the developer remaining on the transport roller 16 by the cleaning member 18 as in the first embodiment described above. Remove.

  Thereby, drying of the developer on the developing roller 9 and the conveying roller 16 can be prevented. Since the toner particles aggregated by the drying of the developer 12 can be prevented from entering the cleaning member 18, deterioration of the edge of the cleaning member 18 (a phenomenon in which the edge is partially chipped) can be prevented.

  As described above, by using the developing device 4A according to the present embodiment, the image forming apparatus including the developing device, and the control method of the developing device 4B, before entering the standby state after the image formation, the transport roller 16 Supply is performed by stopping the supply roller 14 in a state where the developer 12 having the second thickness larger than the first thickness of the regulated developer 12 is supplied over the entire circumference of the supply roller 14. It is possible to prevent the toner particles from being clogged in the concave portion of the roller 14. As described above, also in the present embodiment, substantially the same effect as in the first embodiment can be obtained.

  In the first to third embodiments described above, the case where processing for preventing clogging of toner particles is performed continuously at the end of image formation has been described as an example. However, the present invention is not limited to this. You may perform at the timing when the time when the formation apparatus paused or stopped passed for a fixed time. Further, when used in an office or the like, it may be performed based on an external command input to the operation panel 90 at the timing when the interval between jobs is likely to be freed after the end of the day's work. The timing for performing the processing for preventing clogging of toner particles as described above is included in the time after the image formation is completed and before the image forming apparatus enters the standby state.

  In the first and third embodiments described above, the case where the transport roller 16 is driven by the supply roller 14 has been described as an example. However, the present invention is not limited to this, and the developing device is for rotating the transport roller 16. The conveyance roller 16 may be rotated by separately providing a conveyance roller rotation motor and a conveyance roller rotation detection unit, and the control unit controlling this.

  Although the embodiments of the present invention have been described above, the embodiments disclosed herein are illustrative and non-restrictive in every respect. The scope of the present invention is defined by the terms of the claims, and includes meanings equivalent to the terms of the claims and all modifications within the scope.

  DESCRIPTION OF SYMBOLS 1 Image carrier, 2 Charging device, 3 Exposure device, 4, 4A, 4B Developing device, 5 Intermediate transfer member, 6 Secondary transfer member, 7 Image carrier cleaning device, 8 Intermediate transfer member cleaning device, 9 Developing roller, DESCRIPTION OF SYMBOLS 10 Eraser lamp, 11 Recording medium, 12 Developer, 13 Developer tank, 14 Supply roller, 15 Control blade, 16 Conveying roller, 17 Toner charging device, 18 Cleaning member, 19 Static elimination device, 40 Control part, 50 Rotation drive mechanism , 51 Supply roller rotation motor, 52 Development roller rotation motor, 60 Pressure contact / separation mechanism, 61 Supply roller pressure contact / separation mechanism, 62 Restriction blade pressure contact / separation mechanism, 70 Rotation detection unit, 71 Supply roller rotation detection unit, 72 Development roller Rotation detector, 80 memory, 90 operation panel, 00 image forming apparatus.

Claims (13)

A developing device for developing an electrostatic latent image formed on an image carrier using a developer,
A reservoir for storing the developer containing toner particles and a volatile carrier liquid;
A supply roller that has a plurality of recesses on the surface and is supplied with the developer from the reservoir by rotating;
A conveying roller to which the developer is supplied from the supply roller by rotating in contact with the supply roller;
A developing roller for supplying the developer supplied from the transport roller to the image carrier by rotating in contact with the transport roller;
A regulating member that regulates the developer to a first thickness before the developer supplied to the supply roller from the storage unit is supplied to the transport roller by contacting the supply roller;
A pressure contact / separation mechanism for pressing and separating the regulating member and the transport roller with respect to the supply roller;
A rotation drive mechanism for rotating the supply roller, the transport roller, and the developing roller;
A controller for controlling the operation of the pressure contact / separation mechanism and the operation of the rotation drive mechanism,
The control unit controls the operation of the pressure contact / separation mechanism so that the regulating member and the transport roller are separated from the supply roller before entering a standby state after completion of the developing operation. The developer having the second thickness larger than the first thickness is supplied over the entire circumference of the supply roller by rotating the supply roller one or more times in a state of being separated from the regulating member. A developing device that controls the operation of the rotation drive mechanism to stop the supply roller in a state. A cleaning member that contacts the developing roller and removes the developer remaining on the developing roller after development;
In a state where the control member and the transport roller are separated from the supply roller, the control unit is in a state in which the transport roller and the development roller are in contact with each other before entering a standby state after the development operation is completed. The developer remaining on the transport roller supplied to the development roller via a contact portion between the transport roller and the development roller by rotating the transport roller and the development roller, and the development roller The developing device according to claim 1, wherein the operation of the pressure contact / separation mechanism and the operation of the rotation drive mechanism are controlled so that the developer remaining on the surface is removed by the cleaning member.   When the control unit starts a developing operation from a standby state, the developer on the supply roller is rotated by the restriction member by rotating the supply roller in a state where the restriction member is in pressure contact with the supply roller. After regulating the thickness of the sheet, the supply roller and the transport roller are pressed against each other, and the operation of the press-contact / separation mechanism and the rotation are performed so that the developer whose thickness is regulated is supplied to the transport roller. The developing device according to claim 1, which controls the operation of the drive mechanism. A developing device for developing an electrostatic latent image formed on an image carrier using a developer,
A reservoir for supplying a developer containing toner particles and a volatile carrier liquid;
A supply roller that has a plurality of recesses on the surface and is supplied with the developer from the reservoir by rotating;
A developing roller that rotates in contact with the supply roller to supply the developer from the supply roller and supplies the developer supplied from the supply roller to an image carrier;
A regulating member that regulates the developer to a first thickness before the developer supplied from the storage unit to the supply roller is supplied to the development roller by contacting the supply roller;
A pressure contact / separation mechanism for pressing and separating the regulating member and the developing roller with respect to the supply roller;
A rotation drive mechanism for rotating the supply roller and the developing roller;
A controller for controlling the operation of the pressure contact / separation mechanism and the operation of the rotation drive mechanism,
The control unit controls the operation of the pressure contact / separation mechanism so that the regulating member and the developing roller are separated from the supply roller before entering a standby state after completion of the developing operation. The developer having the second thickness larger than the first thickness is supplied over the entire circumference of the supply roller by rotating the supply roller one or more times in a state of being separated from the regulating member. A developing device that controls the operation of the rotation drive mechanism to stop the supply roller in a state. A cleaning member that contacts the developing roller and removes the developer remaining on the developing roller after development;
The controller is configured to rotate the developing roller in a state in which the developing roller is separated from the supply roller before entering a standby state after completion of the developing operation, thereby removing the developer remaining on the developing roller. The developing device according to claim 4, wherein the operation of the pressure contact / separation mechanism and the operation of the rotation drive mechanism are controlled so as to be removed by the cleaning member.   When the control unit starts a developing operation from a standby state, the developer on the supply roller is rotated by the restriction member by rotating the supply roller in a state where the restriction member is in pressure contact with the supply roller. After regulating the thickness of the roller, the supply roller and the developing roller are pressed against each other so that the developer whose thickness is regulated is supplied to the developing roller and the operation and rotation of the pressing / separating mechanism The developing device according to claim 4, which controls the operation of the drive mechanism. A developing device for developing an electrostatic latent image formed on an image carrier using a developer,
A reservoir for supplying a developer containing toner particles and a volatile carrier liquid;
A supply roller that has a plurality of recesses on the surface and is supplied with the developer from the reservoir by rotating;
A conveying roller to which the developer is supplied from the supply roller by rotating in contact with the supply roller;
A developing roller for supplying the developer supplied from the transport roller to the image carrier by rotating in contact with the transport roller;
A pressure contact / separation mechanism for pressing and separating the transport roller with respect to the supply roller;
A rotation drive mechanism for rotating the supply roller, the transport roller, and the developing roller;
A controller for controlling the operation of the pressure contact / separation mechanism and the operation of the rotation drive mechanism,
The developer supplied to the supply roller is regulated to a first thickness when passing through a contact portion between the supply roller and the transport roller,
The controller controls the operation of the pressure contact / separation mechanism so that the transport roller is separated from the supply roller before entering a standby state after the development operation is finished, and the control unit is in a state of being separated from the transport roller. By rotating the supply roller one or more times, the supply roller is stopped in a state where the developer having the second thickness larger than the first thickness is supplied over the entire circumference of the supply roller. A developing device that controls the operation of the rotation drive mechanism. A cleaning member that contacts the developing roller and removes the developer remaining on the developing roller after development;
The controller is configured such that the transport roller and the development roller are in contact with each other in a state where the supply roller and the transport roller are in contact with each other in a state where the supply roller and the transport roller are separated from each other before entering a standby state after the development operation is completed. By rotating a roller, the developer remaining on the transport roller supplied to the development roller via the contact portion between the transport roller and the development roller, and the residual on the development roller The developing device according to claim 7, wherein the operation of the pressure contact / separation mechanism and the operation of the rotation drive mechanism are controlled so that the developer is removed by the cleaning member. The developing device according to claim 1, wherein a volatilization rate of the carrier liquid is 0.001 g / m ² · min or more and 1 g / m ² · min or less under a use environment temperature.   The developing device according to claim 1, wherein the developer has a viscosity of 10 cSt or more and 500 cSt or less when supplied to the supply roller. A developing device according to any one of claims 1 to 10,
An image carrier on which an electrostatic latent image is formed;
A transfer unit that transfers the toner image formed on the image carrier to the recording medium by developing the electrostatic latent image by the developer supplied from the developing roller to the image carrier; Image forming apparatus. A developing device control method for performing development by supplying a developer stored in a storage unit to an image carrier on which an electrostatic latent image is formed,
As the developer, a developer containing toner particles and a volatile carrier liquid is used,
When the supply roller having a plurality of recesses on the surface rotates and contacts the developer stored in the storage unit, the film thickness of the developer supplied to the supply roller is changed to the first during the developing operation. A method for controlling a developing device, wherein the film thickness is adjusted so that the second film thickness is larger than the first film thickness before entering a standby state after the end of the developing operation.   13. The developer is supplied from the supply roller toward the image carrier after regulating the film thickness of the developer supplied to the supply roller when starting the developing operation from the standby state. A developing device control method as described.

Images