JP2005316198A - Developing device for image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a developing device for an image forming apparatus capable of keeping the powder pressure of developer in a developing chamber constant even by the rotation of a rotary type rack, also restraining the excessive accumulation of deteriorated developer in the developing chamber and a harmful effect thereby, and preventing the spilling of the developer even when a developer storing chamber is made exchangeable as a rotary type developing device equipped with a developer storing chamber and a developing chamber. <P>SOLUTION: The developing chamber is made to communicate with the developer storing chamber in the center direction of the rotary type rack, and the developing chamber is positioned on an upper side than the developer storing chamber when a developing roller in the developing chamber faces to an image carrier. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a developing device in an image forming apparatus such as a copying machine, a printer, a facsimile, or a composite machine using an electrophotographic method, and more particularly, to a cylindrical rotary rack configured to be rotatable, and to an electrophotographic process. The number of colors used is a developing chamber in which a developing roller carrying a developer (toner) for developing the latent image formed in step 1 and a supply roller for supplying developer to the developing roller are provided, and a developer containing chamber. The present invention relates to a developing device in an image forming apparatus that is supported so that each developing roller sequentially faces an image carrier.

  A developing device used in an image forming apparatus such as a copying machine, a printer, a facsimile, or a composite machine using an electrophotographic method does not use a two-component developing method in which a toner and a carrier are used as a developer. A one-component developing system using only toner is known.

  In a one-component developing type developing device, a developer (toner) accommodated in the main body of the device is fed to the surface of the developing roller by a supply roller, and a regulating member is pressed against the developing roller to regulate the amount of developer and friction. The electrostatic latent image formed on the image carrier is developed by charging and rotating the developing roller to guide the developer to the developing area facing the image carrier, and the developer remaining on the surface of the developing roller is supplied to the supply roller. In this way, the developer is separated from the surface and a new developer is supplied to the developing roller.

  However, the developer that has once passed through the supply section and passed through processes such as pressure contact with a regulating member, development, and static elimination is stressed compared to a fresh developer, and the developer is buried due to burial of the post-treatment agent. If charging performance and fluidity deteriorate and such a deteriorated developer accumulates in the vicinity of the developing roller and the supply roller for a long time, if new fresh developer is supplied, the development of charging failure is deteriorated. The agent may be expelled all at once and cause image fogging.

  In addition, when the developer remaining amount is large in the developing chamber, the developer powder pressure becomes too high with respect to the supply roller, and conversely when the developer remaining amount is small, the developer powder pressure becomes low. There is a problem that the amount of developer supplied onto the developing roller becomes unstable and the amount of developer transport varies. In addition, there is a problem that the developer leaks from the regulating member and the seal member when the remaining amount of the developer is large, and in particular, the use of a polymerized developer has recently been increased, but it can be a spherical developer with a small particle size. The higher the hurdle, especially on the sealing surface, against the problem of developer leakage. In this case, if the seal pressure is increased, the developer leakage can be prevented, but there is a problem that the torque becomes too high.

  On the other hand, in a color image forming apparatus, a developing device for the number of colors used in such a color image forming apparatus using a one-component developer is supported by a cylindrical rotary rack configured to be rotatable, and A rotary type developing device is used in which the developing roller in the developing chamber corresponding to the color sequentially faces the image carrier.

  However, in the rotary type developing apparatus, the vertical relationship between the developing chamber and the developer accommodating chamber changes due to rotation of the rotary type rack, resulting in excessive developer supply, fogging, and particle size in the developing chamber. Even if a large developer is returned to the developer storage chamber or developer cartridge, even if a partition member is provided or the developer chamber is separated from the developer cartridge, only the developer having a small particle size is used for development first. Therefore, there is a problem that the developer having a large particle size remains and the image quality of the formed image is gradually deteriorated.

  In addition, during development, if the powder pressure changes significantly due to a new developer entering the developer chamber from the developer storage chamber or developer cartridge for some reason, the already charged developer and the new developer are mixed, resulting in poor charging. There is also a problem that the image quality deteriorates. Contrary to this, even when the developing device is rotated, there is a developer that partially stays and is not used and is not discharged, and the developer cartridge is empty and contains a new developer. When the developer cartridge is replaced, a new developer whose external additive has been replaced and a deteriorated developer are mixed, resulting in a problem that charging failure occurs and image quality is lowered.

  In order to cope with these problems, Patent Document 1 discloses that a regulated space is created by a housing, a supply roller, a developing roller, and a regulating member in contact with the supply roller, and a deteriorated developer is stored in the regulated space during development. When the new developer is prevented from entering from the developer reservoir, and when the deteriorated developer can pass through the regulating member by gravity due to the rotation of the rotary, it is returned to the developer reservoir and mixed with the new developer, There is shown a rotary type developing device which suppresses excessive deterioration developer accumulation and its adverse effects in the developing chamber.

  In Patent Document 2, a plurality of developer replenishing paths that selectively communicate with a plurality of developer replenishing ports are configured to slide along the outer peripheral surface of a cylindrical developer replenishing portion. Corresponding to each chamber, the auger that conveys the developer in the central axis direction conveys the developer while stirring, and extends a member that limits the developer replenishment level below the developer replenishment port. 1 shows a rotary type developing apparatus which prevents developer compaction.

JP 2002-189346 A JP 2001-134045 A

  However, in the rotary type developing device disclosed in Patent Document 1, the regulated space is made by the housing, the supply roller, the development roller, and the regulation member in contact with the supply roller, but the powder pressure in the development chamber is made constant. Since no consideration is given, there is a possibility that the developer charge amount on the developing roller and the transport amount may fluctuate greatly without the powder pressure becoming constant. In addition, the gap between the developer supply roller and the development housing is reduced, and the inflow of new developer is prevented by a developer inflow prevention valve, etc., but the ability to discharge deteriorated developer is poor, and when printing a large number of sheets There is a risk that the developer powder pressure at the restricting portion will rise and cause adverse effects such as developer leakage.

  Further, the rotary type developing device disclosed in Patent Document 2 does not take into account the replenishment timing of the developer and the development position at the time of replenishment, and the developer is developed before the replenished developer is well mixed with the deteriorated developer in the developing chamber. In this case, there is a risk that image fogging may occur.

  Therefore, in the present invention, the developer powder pressure fluctuation in the developing chamber is suppressed and the developer powder pressure is always kept constant, excessive accumulation of the deteriorated developer in the developing chamber and its adverse effect are suppressed, and the developer is accommodated. An object of the present invention is to provide a developing device in an image forming apparatus that does not cause developer spillage even when the chamber is replaceable.

In order to solve the above problems, the present invention
A cylindrical rotary having a developing roller that develops the latent image on an image carrier that carries the latent image by an electrophotographic process, and a supply roller that conveys developer (toner) to the developing roller, and is configured to be rotatable. A plurality of developing chambers that are fixed to the mold rack and rotated to sequentially move the developing roller to a position facing the image carrier, and a developer storage chamber adjacent to each developing chamber. In the developing device in the image forming apparatus,
The developing chamber communicates with the developer accommodating chamber in the central direction of the rotary rack, and is configured to be positioned above the developer accommodating chamber when the developing roller faces the image carrier. It is characterized by.

In order to solve the above problems, the present invention
A cylindrical rotary having a developing roller that develops the latent image on an image carrier that carries the latent image by an electrophotographic process, and a supply roller that conveys developer (toner) to the developing roller, and is configured to be rotatable. A plurality of developing chambers that are fixed to the mold rack and rotated to sequentially move the developing roller to a position facing the image carrier, and a developer storage chamber adjacent to each developing chamber. In the developing device in the image forming apparatus,
A developer container outside the rotary rack; and a means for supplying the developer from the developer container to the developer storage chamber, wherein the developer chamber is in the center direction of the rotary rack. The developer roller is configured to be positioned above the developer accommodating chamber when the developing roller faces the image carrier.

  The developer containing chamber-side partition in the developing chamber is formed so as to be able to store a developing developer when the developing roller faces the image carrier.

  The developer accommodating chamber is configured to be detachable from the rotary rack, and a shutter that opens and closes in conjunction with the attachment and detachment of the developer accommodating chamber is provided at a portion communicating with the developing chamber. And

  Further, when the developer storage chamber is not removable, the developer replenishment from the developer container to the development chamber is performed at a position where the developing roller faces the image carrier or a position before that. Preferably, the developing roller is configured to be replenished one stage before facing the image carrier.

  As described above, when the developing chamber is fixed to the rotary rack and the developer containing chamber is fixed or replaceable adjacent to each developing chamber, and the developer containing chamber is fixed, the developer (toner ) Is provided so that the developing chamber and the developer accommodating chamber communicate with each other in the center of the rotary rack, and the developing chamber accommodates the developer when the developing roller faces the image carrier (developing position). When the rotary type rack is rotated in a direction in which the developing roller is positioned above the developing position, the developer in the developing chamber and the developer containing chamber is separated from the rotary type in each chamber. It gathers in the rack center direction. When the rotary rack is further rotated and the developing roller moves to a position symmetrical with respect to the developing position with respect to the rotation center of the rotary rack, the developer flows into the developing chamber, but further rotates. Thus, after the predetermined angle, the developer returns from the developing chamber to the developer containing chamber, and when the developing roller again faces the image carrier, only an appropriate amount of developer remains in the developing chamber. This does not change even if the amount of developer in the developer storage chamber decreases, and only a certain amount of developer always remains in the development chamber.

  As a result, the developer in the developing chamber once returns to the developer containing chamber as the rotary rack rotates, and is then mixed with the new developer and then supplied to the developing chamber. It is suppressed. In addition, since the amount of developer stored in the developing chamber is limited at the developing position, the powder pressure does not fluctuate at all in the developing chamber. However, neither the phenomenon that the toner powder pressure becomes too high, or the phenomenon that the toner powder pressure becomes too low when the toner remaining amount is low, will cause problems such as unstable developer amount on the developing roller and fluctuations in the developer transport amount. Absent. Further, since there is no developer leakage from the restricting portion or the seal portion that occurs when the remaining amount of the developer is large, it is not necessary to increase the seal pressure in order to deal with them. The developing device can be provided.

  In a preferred embodiment, the developer storage chamber side partition in the developing chamber is formed so as to be able to store a developing developer when the developing roller faces the image carrier.

  When the developer accommodating chamber is configured to be detachable from the rotary rack, a shutter that opens and closes in conjunction with the attachment and detachment of the developer accommodating chamber is provided at a portion communicating with the developing chamber. As a result, even if the developer storage chamber is removed, the developer does not leak out and the inside of the apparatus or the recording medium is not soiled.

  Further, when the developer storage chamber is not removable, the developer is replenished from the developer container to the development chamber at a position where the developing roller faces the image carrier or a position before that, preferably, By setting the developing roller one step before facing the image bearing member, the supplied new developer is fed to the developing chamber only after the rotary rack has been rotated one or more times. It is possible to provide a developing device that can prevent the image fog from being caused by the developer being used without being well mixed with the deteriorated developer in the developing chamber.

  Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the drawings. However, the dimensions, materials, shapes, relative arrangements, and the like of the components described in this embodiment are not intended to limit the scope of the present invention unless otherwise specified, but are merely illustrative examples. Not too much.

  FIG. 1 is a diagram showing a schematic configuration of a color image forming apparatus provided with a developing device according to a first embodiment of the image forming apparatus of the present invention, and FIG. 3 is a perspective view of the developing device according to the present invention when the shutter of the developer storage chamber made removable is opened, and FIG. 4 is a perspective view of the developer storage chamber of the developing device according to the present invention. FIG. 5 is a perspective view showing an opening / closing mechanism, and FIG. 5 is a diagram for explaining the movement of the developer in the developing chamber and the developer containing chamber due to the rotation of the rotary rack when there is sufficient developer (toner) in the developing device. FIG. 6 is a view for explaining the movement of the developer in the developing chamber and the developer accommodating chamber by the rotation of the rotary rack and the position for exchanging the developer accommodating chamber when the developer is reduced in the developing device. FIG. 7 shows the image of the present invention. FIG. 8 is a diagram illustrating a schematic configuration of an image forming apparatus including a second embodiment of a developing device in the forming apparatus, and FIG. 8 is a diagram illustrating an example of a developer supply mechanism to a developer storage chamber in the developing device of the second embodiment. is there.

In the drawings, the same components are denoted by the same reference numerals, 1 is an exposure apparatus using, for example, a laser scanning unit, 2 is a photoreceptor (image carrier) drum, 3 is a charging device, and 4 is an embodiment of the present invention. In the rotary developing device of Example 1, for example, a developing chamber 41 (developing housing) indicated by black (BK) 41 ₁ , magenta (M) 41 ₂ , cyan (C) 41 ₃ , and yellow (Y) 41 ₄ , respectively. black provided corresponding to the developing chamber (BK) 42 _1, magenta (M) 42 _2, cyan (C) 42 _3, yellow (Y) 42 ₄ of the developer (toner) containing chamber (developer cartridge) 42, and a driving unit is connected via a clutch to drive the driving unit to rotate the rotary developing device, and the developing roller 47 in each color developing chamber 41 is Next photoconductor by the developing position facing the (image bearing member) drum 2 and develops the latent image on the photosensitive member (image bearing member) drum 2. 5 is a rubbing member for cleaning, 6 is a cleaning device, 7 is an intermediate transfer unit, 71 is an intermediate transfer belt, 72 is a primary transfer roller, 8 is a fixing device, 9 is a paper feed cassette, and 10 is a secondary transfer roller. , 11 is a recording medium discharge unit, and 12 is a cleaning device for the intermediate transfer belt 71. Note that the development chambers 41 (development housings) indicated by black (BK) 41 ₁ , magenta (M) 41 ₂ , cyan (C) 41 ₃ , and yellow (Y) 41 ₄ have the same configuration. Different configurations may be used.

4 and 5, reference numeral 40 denotes a cylindrical rotary rack, and a space formed between the front and rear side walls 40a and 40b having a substantially disk shape and the front and rear side walls is used for four color developments. A partition wall 40c having a cross-shaped cross section is provided for equally dividing the cross section. In each of the partitioned spaces, the above-described four developing units of black (BK) 41 ₁ , magenta (M) 41 ₂ , cyan (C) 41 ₃ , and yellow (Y) 41 ₄ are arranged.

  Referring to FIG. 2, a developing chamber (developing housing) 41 is disposed on the upper side of the space defined by the partition wall 40 c, and a developer storage chamber that can be replaced below the developing chamber 41. A (developer cartridge) 42 is positioned. The developer accommodating chamber 42 has an external shape as shown in FIG. 3, and is a curved portion along the circumference of the substantially fan-shaped front and rear side wall portions 42a and the front and rear side walls 40a and 40b of the rotary rack. 42b, a side wall 42c that contacts the partition wall 40c of the rotary rack, and the remaining side wall 42d, and a developer (one-component developer) 45 is accommodated therein.

  A substantially convex fan-shaped side wall portion 42 a of the developer accommodating chamber is provided with a guide convex portion 421 for fixing the developer accommodating chamber (developer cartridge) 42 to the cylindrical rotary rack 40.

  Next, referring to FIG. 3, a part of the side wall 42 d is formed with a shutter 43 that opens and closes in conjunction with the attachment and detachment to the cylindrical rotary rack 40. It is configured to be openable and closable around a rotating shaft 422 positioned at a ridge 42e where the side walls 42c and 42d contact. The shutter 43 may incorporate a spring (not shown) that closes the shutter 43 when the developer accommodating chamber (developer cartridge) 42 is removed from the cylindrical rotary rack 40. 431 is an opening / closing protrusion provided to open and close the shutter 43, 401 is a guide groove provided in the cylindrical rotary rack 40 and into which the guide convex portion 421 of the developer storage chamber (developer cartridge) 42 is inserted, 402 Is a shutter opening / closing groove that is provided in the cylindrical rotary rack 40 and guides an opening / closing protrusion 431 provided in the shutter 43 of the developer storage chamber (developer cartridge) 42. Although not shown in the figure, a guide convex portion 421 is also formed on the rear side wall portion 42a, and an opening / closing projection 431 is formed on the rear side of the shutter 43. A groove 402 is formed.

Returning to FIG. 2 again, the configuration of the developing chamber 41 will be described.
A developing roller 47 is positioned in the developing chamber 41 so as to oppose the photosensitive drum 2, and the electrostatic charge latent image formed on the surface of the photosensitive drum 2 as described above is held on the surface of the roller 47. It can be developed with a one-component developer. A supply roller 46 is positioned on the opposite side of the photosensitive drum 2 with respect to the developing roller 47. The supply roller 46 and the developing roller 47 may or may not be in contact with each other. In this embodiment, the supply roller 46 rotates in the counter direction with the developing roller 47 while being in contact with the developing roller 47.

  Between the developing roller 47 and the partition wall 40c of the rotary rack 40 adjacent to the roller 47, a regulating blade 48 for regulating the developer layer thickness on the developing roller 47 and charging the developer is provided. . In this specific example, it is directly attached to the partition wall 40 c of the rotary rack 40. The regulating blade 48 may be provided with a thin metal plate-like member such as stainless steel or phosphor bronze, or an elastic member such as rubber or a resin member at the tip of the metal plate-like member. The regulation blade 48 is fixed to the wall of the developing chamber 41 in a so-called counter state so that the tip (free end) of the regulation blade is located upstream of the fixed end in the rotation direction of the developing roller 47. Although the tip of the regulating blade 48 is not bent, the tip may be bent to adjust the toner conveyance amount, and the tip shape is not particularly defined. The regulating blade 48 is in elastic contact with the surface at the contact position with the developing roller 47. Therefore, depending on the contact state of the regulating blade 48, more specifically, the toner formed on the surface of the developing roller 47 by the protruding amount from the contact portion to the tip, the regulating pressure, the tip shape, the free length of the regulating blade 48, etc. The thickness of the layer is finally determined, and the toner on the developing roller 47 is charged to a predetermined polarity by rubbing against the regulating blade 48 at this contact position.

  On the other hand, in FIG. 2, a side wall 41 a is provided below the developing roller 47 so as to be attached to the front and rear side walls 40 a and 40 b of the rotary rack 40 so that the developer 44 does not spill from the developing chamber 41. A surface 41b parallel to the tangential direction with respect to the roller surface of the developing roller 47 is formed at the end of the developing chamber side wall 41a, and the developer leaks to the outside from between the developing roller 47 and the developing chamber side wall 41a. A static elimination seal 49 is provided to eliminate the static electricity.

  In the state where the developing roller 47 as shown in FIG. 2 is positioned so as to be developable with respect to the photosensitive drum 2, the side wall 42 d of the developer storage chamber 42 faces the rotational center of the rotary rack. The developer reservoir 44 can be formed in cooperation with the adjacent developing chamber side wall 41a, and a part of the supply roller 46 described above is in this state. A portion thereof is positioned at 44. Thus, the developer in the developer reservoir 44 is supplied to the developing roller 47 as the supply roller 46 rotates, and the developer on the developing roller 47 is in the state of a predetermined amount of toner thin layer by the regulating blade 48. The electrostatic charge latent image formed thereon can be carried. In the following description, the present invention will be described using a non-magnetic developer as an example, but the present invention can also be applied to a developing device using a magnetic developer.

First, the image forming operation of the image forming apparatus having the rotary type developing device 4 according to the present invention will be briefly described with reference to FIG. 1. In the standby state, for example, black (BK) in the rotary type developing device 4 in FIG. use developing chamber 41 ₁ is such that a developing position facing the photosensitive member (image bearing member) drum 2. When image data is sent to a control device (not shown), the image data is decomposed into data of each color of black (BK), magenta (M), cyan (C), and yellow (Y). The photosensitive member (image carrier) drum 2 is uniformly charged by the charging device 3.

  First, black (BK) data is given to the exposure device 1 to expose the photosensitive member (image carrier) drum 2, and when a latent image is formed, it is carried by the developing roller provided in the developing chamber 41. The toner is developed with the developed developer (toner) to form a toner image, and the toner image is transferred to the intermediate transfer belt 71 by a primary transfer roller 72 to which a primary transfer bias is applied. The developer (toner) remaining after the formed toner image is transferred to the intermediate transfer belt 71 is cleaned by the cleaning rubbing member 5 and the cleaning device 6, and the next image formation is performed. The secondary transfer roller 10 and the cleaning device 12 that are in contact with the intermediate transfer belt 71 are separated from the intermediate transfer belt 71 until the toner images of all colors are transferred onto the intermediate transfer belt 71 in an overlapping manner. .

Thus rotating the toner image formation requires only the drawing counterclockwise rotary type developing device 4 of black (BK), a developing chamber 41 ₂ is the photoreceptor of the following magenta (M) (image bearing member) to the drum 2 The image data of magenta (M), which is the development position facing each other and is previously decomposed, is given to the exposure apparatus 1 for exposure. And is developed becomes a toner image by the photosensitive member (image bearing member) drum 2 latent image is formed on the developer it developing roller provided in the developing chamber 41 ₂ is supported (toner), the intermediate transfer belt 71 The toner image is superimposed and transferred onto a black (BK) toner image transferred thereon.

  The same operation is repeated with cyan (C) and yellow (Y) image data, and when all color toner images are transferred to the intermediate transfer belt 71 to form a full-color toner image, the intermediate transfer belt 71 first. The secondary transfer roller 10 and the cleaning device 12 that are separated from each other are brought into contact with the intermediate transfer belt 71, and the recording medium taken out from the paper feed cassette 9 is sent to the secondary transfer position where the secondary transfer roller 10 is located. Thus, the full color toner image is transferred to the recording medium.

  The recording medium onto which the full color toner image has been transferred in this manner is further sent to the fixing device 8 where it is fixed by heat and pressure, and is discharged to the discharge unit 11. The developer (toner) remaining on the intermediate transfer belt 71 is cleaned by the cleaning device 12 and prepared for the next image formation.

  Such a rotary type developing device 4 in the image forming apparatus of the present invention includes a developing chamber (developing housing) 41 of one color opposed to the photosensitive member (image carrier) drum 2 in FIG. As shown in the configuration of the developer storage chamber (developer cartridge) 42, a developing chamber (developing housing) 41 is fixed to a cylindrical rack 40 in the rotary developing device 4, and is provided in the developing chamber (developing housing) 41. When the developed developing roller 47 faces the photosensitive member (image carrier) drum 2, the developer containing chamber (developer cartridge) 42 is a cylindrical rotary type so as to be adjacent to the developing chamber 41 and on the lower side. The rack 40 or each developing chamber 41 is detachably supported by a positioning member and a coupling member (not shown).

  The developer storage chambers (developer cartridges) 42 for the respective colors are exchanged from the position where the developing roller 47 of the developing chamber 41 faces the photosensitive member (image bearing member) drum 2 as will be described later. When the developing roller 47 rotates to a position facing the photosensitive member (image carrier) drum 2, that is, the developing roller 47 in the developing chamber 41 is on the upper side, and the developer containing chamber (developer cartridge) 42 is also on the upper side. In this case, the upper cover of the image forming apparatus can be opened from above, and a coupling member (not shown) is fixed by a stopper member linked to the rotary rotation position so that the image forming apparatus can be detached only at this position. Yes.

  In the developing chamber 41, there are a developing roller 47, a supply roller 46 for supplying a one-component developer to the developing roller 47, a regulating blade 48 for regulating the developer layer thickness on the developing roller 47 and charging the developer, and a developer. A neutralization seal 49 is provided to prevent leakage to the outside and neutralize, and the amount of developer on the developing roller 47 is equalized to a predetermined amount by the regulating blade 48 and is positioned close to the photosensitive member (image carrier) drum 2. Thus, the developer is attached to the latent image by the bias potential.

  Further, the partition between the developing chamber 41 and the developer containing chamber 42 is optimal for developing the developing developer when the developing roller 47 comes to the developing position where the developing roller 47 faces the photosensitive member (image carrier) drum 2. It is formed so that only the amount can be stored.

  When the developer accommodating chamber 42 is replaceable as a developer cartridge, the developer accommodating chamber (developer cartridge) 42 is interlocked with the attachment / detachment to the cylindrical rotary rack 40 as shown in FIGS. Then, a shutter 43 is provided that can be opened and closed and closed by a spring or the like (not shown) as shown in FIG. 4A when removed from the cylindrical rotary rack 40.

  3 and 4, reference numeral 421 denotes a guide convex portion for fixing the developer storage chamber (developer cartridge) 42 to the cylindrical rotary rack 40, 422 denotes a rotating shaft of the shutter 43, and the developer described above. A spring (not shown) that closes the shutter 43 when the storage chamber (developer cartridge) 42 is removed from the cylindrical rotary rack 40 may be incorporated in this portion. 431 is an opening / closing protrusion provided to open and close the shutter 43, 401 is provided on the front and rear side walls 40a, 40b of the cylindrical rotary rack 40, and the guide convex portion 421 of the developer accommodating chamber (developer cartridge) 42 is provided. A guide groove 402 to be inserted is also provided on the front and rear side walls 40a and 40b of the cylindrical rotary rack 40, and is used for opening and closing the shutter for guiding the opening and closing protrusion 431 provided on the shutter 43 of the developer storage chamber (developer cartridge) 42. It is a groove.

  When the developer storage chamber (developer cartridge) 42 is removed from the cylindrical rotary rack 40, the shutter 43 is closed by the spring force (not shown) as shown in FIG. The developer contained therein is not spilled. Then, the guide convex portion 421 in the developer storage chamber (developer cartridge) 42 is put into a guide groove 401 provided in the front and rear side walls 40a and 40b of the cylindrical rotary rack 40 shown in FIG. When the opening / closing protrusion 431 of the shutter 43 is inserted into the shutter opening / closing groove 402 of the cylindrical rotary rack 40 and inserted into the cylindrical rotary rack 40, the shutter opening / closing groove 402 is bent in the middle, so that the shutter 43 is shown in FIG. 3 opens and communicates with the developing chamber 41 in the central direction of the cylindrical rotary rack 40, so that the developer inside is in the developing chamber 41 and the developer containing chamber (developer cartridge) 42. You will be able to move freely between.

  In the above description, the mechanism shown in FIGS. 3 and 4 is shown as an example of the opening / closing mechanism of the shutter 43. However, the mechanism is not limited to such a mechanism, and is opened when inserted into the cylindrical rotary rack 40. Needless to say, any mechanism may be employed as long as it is closed when removed from the cylindrical rotary rack 40.

The developing device according to the present invention configured as described above moves as shown in FIG. 5 when the stored developer is sufficient. First, in the developing position where the developing roller 47 ₁ is facing the photosensitive member (image bearing member) drum 2, as shown in FIG., The partition walls 40c cross section cross-shaped rotary rack 40, the partition The wall 40c is positioned slightly inclined with respect to the horizontal or vertical direction, and the side wall 42d of the developer accommodating chamber 42 is inclined so as to rise toward the rotation center of the rotary rack as shown in FIG. The developer reservoir 44 can be formed in cooperation with the adjacent developing chamber side wall 41a. As a result, in the developing position, leaving only the developer 44 ₁ stored in the 42d side walls of the developer accommodating chamber 42, mostly, are stored in the positioned under developing chamber developer accommodating chamber 42 ₁ Yes. Thus, the developer 44 ₁ in the developing chamber 41 ₁ is the optimum amount to the developer, other developers have been stored in such a state that the developer accommodating chamber (developer cartridge) 42 ₁ to 45 _1.

By rotation of the drawing immediately after the termination of development of the counterclockwise cylindrical rotary rack 40, the developing chamber comes to a position where the developing roller 47 ₁ is shown in FIG. 5 to 41 ₄ as the upper in the developing chamber 41 ₁ When the developer 44 ₁ in the developing chamber shown in ₄₁₁ is dropped toward the center of the cylindrical rotary rack 40 is at the position of the 41 _4, also developer chamber (developer cartridge) 42 in the _first developer Similarly, they gather in the central direction of the cylindrical rotary rack 40.

When further rotating the cylindrical rotary rack 40 becomes the position shown in FIG. 5 to 41 _3, 42 _3, the developer that has been in the developing chamber 41 ₁ on its way, the developer accommodating chamber (developer cartridge ) now while mix with 42 ₁ of fresh developer flows into the developing chamber 41 _3, at the position shown further a cylindrical rotary rack 40 is rotated in 5 to 41 _2, 42 _2, developer of the developer from flowing into the chamber 41 ₂ stops. Then, when the further rotation of the cylindrical rotary rack 40, the developer that has been in the developing chamber 41 ₂ on the way to the development position shown in FIG. 5 to 41 _1, 42 _1, leaving the optimum amount to the developer spilled developer accommodating chamber (developer cartridge) 42 ₁ side Te, upon reaching the developing position, the developer 44 ₁ in the developing chamber 41 ₁ is the optimum amount to the developer.

  This is exactly the same when the amount of developer in the developer accommodating chamber (developer cartridge) 42 is reduced, and the developer accommodating chamber (developer cartridge) 42 and the developing chamber 41 are formed into a cylindrical rotary rack 40. , The developer is always filled in the developing chamber 41 by the rotation of the cylindrical rotary rack 40, and then unnecessary developer spills into the developer containing chamber (developer cartridge) 42. Therefore, only a constant developer remains in the developing chamber 41 at all times.

FIG. 6 shows the movement of the developer and the replacement position of the developer storage chamber (developer cartridge) 42 when the amount of developer in the developer storage chamber (developer cartridge) 42 decreases. is there. That is, in FIG. 6, at the development position where the developing roller 47 ₁ is facing the photosensitive member (image bearing member) drum 2, but the developer 44 ₁ in the developing chamber 41 ₁ is in the optimum amount to the developer, developer accommodating chamber (developer cartridge) 42 ₁ of the developer is very small as 45 _1.

Then, the drawing counterclockwise cylindrical rotary rack 40 is rotated as described, the developing chamber 41 ₁ comes to the position shown in 41 _4, the developer 44 ₁ in the developing chamber 41 ₁ of the 41 ₄ in the position falls in the center of the cylindrical rotary rack 40, the developer accommodating chamber (developer cartridge) 42 small mountain 45 shown with the developer in ₁ toward the center of the cylindrical rotary rack 40 by a dotted line ₄

When further rotating the cylindrical rotary rack 40 becomes the position shown in FIG. 6 at 41 _3, 42 _3, the developer 45 ₄ as it flows into the developing chamber 41 _3, further a cylindrical rotary rack 40 rotates If _is, 41 2, 42 positions from ₄₁ 1 shown in _2, 42 on the way to the development position indicated by _1, the developer that has been in the developing chamber 41 _2, developer, leaving only the optimum amount to the developer accommodating chamber spills (developer cartridge) 42 ₁ side, when it reaches the development position, the developer 44 ₁ in the developing chamber 41 ₁ is in the optimum amount for development.

When the developer accommodating chamber (developer cartridge) developer 42 becomes less replacement is required, as shown in FIG. 6, the cylindrical developer accommodating chamber (developer cartridge) at a position of 42 ₄ When trying to retrieve from Jo rotary rack 40, FIG. 4 by the shutter opening and closing grooves 402 shown in moved in the direction of closing between the shutter 43 opening and closing projection 431 of the shutter 43 reaches the bent portion, indicated by 45 ₄ 6 mountain developer the developer accommodating chamber (developer cartridge) is taken into 42 _4, it is possible to replace the developer accommodating chamber (developer cartridge) 42 ₄ without causing the developer spills.

That is, in the developing device of the present invention, be less even if most developer amount in the developer accommodating chamber (developer cartridge) 42, a developing roller 47 ₁ faces the photosensitive member (image bearing member) drum 2 a developer amount 44 ₁ is always constant at the developing position are, moreover the developer is supplied to the developing chamber after commingled with the new developer by rotation of the cylindrical rotary rack 40, the deterioration developer storage Therefore, the above-described adverse effects are not caused. In addition, since the powder pressure in the developing chamber 41 does not fluctuate at all, the developer powder pressure increases when the developer remaining amount is large as in the prior art, and conversely the developer powder pressure when the developer remaining amount is small. None of the decrease occurs, and problems such as instability of the developer amount on the developing roller 47 and fluctuations in the developer conveyance amount do not occur. Further, since there is no developer leakage from the restricting portion or the seal portion that occurs when the remaining amount of the developer is large, it is not necessary to increase the seal pressure in order to deal with them. The developing device can be provided.

  The above is the first embodiment of the developing device of the present invention. The developer storage chamber 42 of the present invention is not only made to be replaceable as a developer cartridge, but is also fixed to the cylindrical rotary rack 40 and provided separately. The developer container may be replenished. The embodiment in this case is shown in the embodiment 2 shown in FIGS.

  7 and 8 are different from the first embodiment shown in FIG. 1 in that the structure of the rotary type developing device 80 and the developer storage chamber 82 constituting the rotary type developing device 80 are supplied with the developer. A developer container 83 provided outside the rotary type developing device 80, and a means for supplying the developer from the developer container 83 to the developer storage chamber 82. The description is omitted.

In the rotary type developing apparatus of Embodiment 2 in figure 80 is the present invention, for example, black (BK) 81 _1, magenta (M) 81 _2, cyan (C) 81 _3, yellow (Y) 81 developing chamber shown in ₄ 81, black (BK) 82 _1, magenta (M) 82 _2, cyan (C) 82 _3, yellow (Y) 82 ₄ of the developer (toner) and storage chamber 82 is fixed to a cylindrical rotary rack 90 The developing chamber 81 for each color and the developer (toner) containing chamber 82 are communicated with each other in the center direction of the rotary rack.

  Reference numeral 83 denotes a developer container that stores developer of each color, 84 denotes a developer supply pipe for supplying the developer from the developer container 83 to the rotary type developing device 80, and 85 denotes a developer supply unit in the rotary type developing device 80. , 86 is a spiral member that sends the supplied developer to the developer storage chamber 82 of the rotary type developing device 80, and 87 is black (BK), magenta (M), cyan (C) in the axial direction of the developer supply unit 85. , Partition ribs for separating the yellow (Y) supply space to prevent color mixing of the developer, 88 a developer supply port, 89 a developer supply chamber containing a spiral member 86, and 90 a rotary rack It is.

  As shown in FIG. 8A, the rotary type developing device 80 according to the second embodiment includes a plurality of developer supply pipes 84 corresponding to the respective developer containers 83 provided on the outside. Provided at one end of the apparatus 80 in the axial direction and connected to a developer supply unit 85 for supplying the developer to the rotary type development device 80, and from the developer supply unit 85 to the other end of the rotary type development device 80. A spiral member 86 is provided corresponding to each color, and the developer is sent to each developer storage chamber 82.

As shown in FIGS. 8B and 8C, the developer supply unit 85 is formed of black (BK), magenta (M), cyan (C), and yellow (Y) by a disk-shaped partition rib 87. The developer replenishment spaces are separated in the axial direction to prevent color mixing of the developers, and the developer replenishment ports 88 ₁ , 88 ₂ ,. Are provided in a housing (not shown) that covers the developer supply portion 85, and a developer supply pipe 84 is connected to the supply spaces of the respective colors separated by the partition ribs 87.

  Further, as shown in the partially cutaway view of FIG. 8C, the developer supply unit 85 extends the partition walls for separating the colors in the rotary rack 90 shown in FIG. 7 to the developer supply unit 85. A developer feeding chamber 89 formed as described above is provided, and the spiral member 86 is provided in the developer feeding chamber 89 so that the developer is sent to each developer storage chamber 82.

Therefore, the rotary type developing apparatus 80 of Embodiment 2 shown in FIG. 7, the developer supply pipe 84 coming on the diagram above as shown in Fig., For example, 86 ₄ of the spiral member shown in FIG. 7 8 (A) when positioned just below the supply opening of being adapted supply opening of the developer supply pipe 84 comes on top of the developer supply opening 88 ₄ as shown in FIG. 8 (B), therefore the developer is the from the developer supply opening 88 ₄ is supplied to the spiral member 86 are sent to the developer chamber 82.

The developer sent to the developer storage chamber 82 is mixed with the developer in the developer storage chamber 82. As described above, this new developer is sent directly to the development chamber 81. If it is used for development without being well mixed with the deteriorated developer, image fogging occurs. In the present invention therefore, covered by a pipe (not shown) a portion of the developer accommodating chamber 82 of the spiral member 86, an opening is provided in the developer accommodating chamber 82 side of the pipe, shown at 82 ₂ in FIG. 7 The developer in the pipe is prevented from being supplied to the developer accommodating chamber 82 until the developer accommodating chamber 82 comes to the position.

  Therefore, since the developer supplied by the spiral member 86 is first supplied to the developer storage chamber 82, this new developer is not used when the development chamber 81 reaches the development position, and the rotary type developing device is no longer used. When the developing chamber 81 reaches the developing position after one rotation, it is used for developing, and during that time, it is well mixed with other developer, so that image fogging occurs because it is not mixed with the deteriorated developer as described above. It does not cause problems such as. The movement of the developer accommodated in each developing chamber 81 and developer accommodating chamber 82 is exactly the same as the movement described with reference to FIGS.

  As described above, when the developing chamber is fixed to the rotary rack and the developer containing chamber is fixed or replaceable adjacent to each developing chamber, the developer containing chamber is fixed. A developer supplying means is arranged to connect the developing chamber and the developer containing chamber in the center direction of the rotary rack, and when the developing roller faces the image carrier (developing position), the developing chamber becomes the developer. When the rotary rack is rotated in the direction in which the developing roller is positioned above by being configured to be positioned above the storage chamber, the developer in the development chamber and the developer storage chamber is directed toward the center of the rotary rack in each chamber. Get together. When the rotary rack is further rotated and the developing roller moves to a position symmetrical with respect to the developing position with respect to the rotation center of the rotary rack, the developer flows into the developing chamber, but further rotates. Thus, after the predetermined angle, the developer returns from the developing chamber to the developer containing chamber, and when the developing roller again faces the image carrier, only an appropriate amount of developer remains in the developing chamber. This does not change even if the amount of developer in the developer storage chamber decreases, and only a certain amount of developer always remains in the development chamber.

  As a result, the developer in the developing chamber once returns to the developer containing chamber as the rotary rack rotates, and is then mixed with the new developer and then supplied to the developing chamber. It is suppressed. In addition, since the amount of developer stored in the developing chamber is limited at the developing position, the powder pressure does not fluctuate at all in the developing chamber. The phenomenon that the developer becomes too high, or the developer powder pressure becomes too low when the remaining amount of the developer is low, does not occur, and the developer amount on the developing roller is unstable or the developer transport amount fluctuates. Does not occur. Further, since there is no developer leakage from the restricting portion or the seal portion that occurs when the remaining amount of the developer is large, it is not necessary to increase the seal pressure in order to deal with them. The developing device can be provided.

  When the developer accommodating chamber is configured to be detachable from the rotary rack, a shutter that opens and closes in conjunction with the attachment and detachment of the developer accommodating chamber is provided at a portion communicating with the developing chamber. As a result, even if the developer storage chamber is removed, the developer does not leak out and the inside of the apparatus or the recording medium is not soiled.

  Further, when the developer storage chamber is not removable, the developer is replenished from the developer container to the development chamber at a position where the developing roller faces the image carrier or a position before that, preferably, By setting the developing roller one step before facing the image bearing member, the supplied new developer is fed to the developing chamber only after the rotary rack has been rotated one or more times. It is possible to provide a developing device that can prevent the image fog from being caused by the developer being used without being well mixed with the deteriorated developer in the developing chamber.

  According to the present invention, the developer powder pressure in the developing chamber is always kept constant, the accumulation of deteriorated developer and its adverse effects are suppressed, and a high quality image is always obtained, and the developer containing chamber can be replaced. In this case, it is possible to provide a developing device in an image forming apparatus that does not cause developer spillage.

1 is a diagram illustrating a schematic configuration of an image forming apparatus including a developing device according to a first embodiment of the image forming apparatus of the present invention. FIG. 2 is an enlarged schematic view of a developing unit in Embodiment 1 of the developing device according to the present invention. It is a perspective view at the time of opening the shutter of the developer accommodating chamber made removable in the developing device according to the present invention. It is the perspective view which showed the shutter opening / closing mechanism of the developer accommodating chamber made removable in the developing device which becomes this invention. FIG. 10 is a diagram for explaining the movement of the developer in the developing chamber and the developer containing chamber due to rotation of the rotary rack when there is sufficient developer in the developing device. FIG. 10 is a diagram for explaining the movement of the developer in the developer chamber and the developer accommodating chamber by the rotation of the rotary rack and the position where the developer accommodating chamber is exchanged when the developer is reduced in the developing device. FIG. 5 is a diagram illustrating a schematic configuration of an image forming apparatus including a developing device according to a second embodiment of the image forming apparatus of the present invention. FIG. 6 is a diagram illustrating an example of a developer supply mechanism to a developer storage chamber in the developing device according to the second embodiment.

Explanation of symbols

2 Photosensitive member (image carrier) drum 40 Cylindrical rotary rack 41 Developing chamber (developing housing)
41 ₁ Black (BK) developing chamber 41 ₂ Magenta (M) developing chamber 41 ₃ Cyan (C) developing chamber 41 ₄ Yellow (Y) developing chamber 42 Developer accommodating chamber (developer cartridge)
42 ₁ Black (BK) developer accommodating chamber 42 ₂ Magenta (M) developer accommodating chamber 42 ₃ Cyan (C) developer accommodating chamber 42 ₄ Yellow (Y) developer accommodating chamber 43 Shutter 44 Developer 45 Developer Developer 46 in the cartridge Supply roller 47 Developing roller 48 Regulating blade 49 Static elimination seal

Claims (6)

A cylindrical rotary having a developing roller that develops the latent image on an image carrier that carries the latent image by an electrophotographic process, and a supply roller that conveys developer (toner) to the developing roller, and is configured to be rotatable. A plurality of developing chambers that are fixed to the mold rack and rotated to sequentially move the developing roller to a position facing the image carrier, and a developer storage chamber adjacent to each developing chamber. In the developing device in the image forming apparatus,
The developing chamber communicates with the developer accommodating chamber in the central direction of the rotary rack, and is configured to be positioned above the developer accommodating chamber when the developing roller faces the image carrier. A developing device in an image forming apparatus. A cylindrical rotary having a developing roller that develops the latent image on an image carrier that carries the latent image by an electrophotographic process, and a supply roller that conveys developer (toner) to the developing roller, and is configured to be rotatable. A plurality of developing chambers that are fixed to the mold rack and rotated to sequentially move the developing roller to a position facing the image carrier, and a developer storage chamber adjacent to each developing chamber. In the developing device in the image forming apparatus,
A developer container outside the rotary rack; and a means for supplying the developer from the developer container to the developer storage chamber, wherein the developer chamber is in the center direction of the rotary rack. And a developing device in the image forming apparatus, wherein the developing roller is positioned above the developer accommodating chamber when the developing roller faces the image carrier.   3. The developer containing chamber-side partition in the developing chamber is formed so as to be able to store a developing developer when the developing roller faces the image carrier. A developing device in the image forming apparatus.   2. The developing device in an image forming apparatus according to claim 1, wherein the developer storage chamber is configured to be detachable from the rotary rack.   5. The developing device in an image forming apparatus according to claim 4, wherein the developer accommodating chamber is provided with a shutter that opens and closes in conjunction with the attachment and detachment of the developer accommodating chamber at a portion communicating with the developing chamber. .   The developer replenishment from the developer container to the developing chamber is configured such that the developing roller is performed at a position where the developing roller faces the image bearing member or at a position before the developing roller. The developing device in an image forming apparatus according to claim 2, wherein the developing device is configured to supply the toner before one stage facing the body.

Images