JPH0633480Y2 - Development device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a developing device using a two-component developer composed of toner and carrier, and more specifically, to developing a used developer whose carrier has deteriorated into a new developer. The present invention relates to a developing device that can be easily exchanged for a developer and has a greatly extended device life.

[Prior art and its problems]

FIG. 6 shows a developing device using a dry two-component developer in a conventional electrophotographic image forming apparatus. In the figure,
The developing device A is generally composed of a toner replenishing chamber 61 that stores replenishment toner t on the upper side, and a developing chamber 62 that stores a developer d in which a toner and a carrier are mixed on the lower side. Development room
The developing sleeve 64 is located in the opening facing the photosensitive drum 63 of 62.
Is provided, and the developer d is rotated by being rotated in the direction of the arrow.
Is conveyed to the developing position D adjacent to the photoconductor drum 63 by an appropriate amount, and is applied to the electrostatic latent image formed on the photoconductor drum 63 to visualize the latent image as a toner image.

In the developer d, the toner and the carrier rub against each other while being agitated by the agitating roll 65 in the developing chamber 62, and the toner is charged with a necessary electric charge having a predetermined polarity. At the developing position D, only the toner is used for development, and the carrier is returned into the developing chamber 62 as the developing sleeve 64 rotates. While the toner t is replenished several times and the carrier is repeatedly used, the carrier eventually deteriorates and the desired effect cannot be obtained.
The carrier will need to be replaced.

By the way, in recent years, along with the downsizing of image forming apparatuses such as printers, simplification of maintainability is required, and when exchanging a consumable material such as a developer, a unit exchanging method in which all parts relating to the material are disposable It is used a lot.
Therefore, in the above-described developing device, the life of the developing device unit is defined as the time when the carrier deteriorates, and each developing device unit is replaced with a new one. In this case, components such as the developing sleeve 64 and the stirring roll 65 can still be used sufficiently, and discarding them together is extremely uneconomical and causes an increase in running cost.

Also, other consumable parts such as photosensitive drums and cleaners are often replaced with a unit, but in order to simplify maintenance work, the photosensitive drums, cleaners, and developing units should be replaced as a single process unit for batch replacement. There is a demand for a method to do so. In this case, since the life of the photosensitive drum is usually much longer than the life of the developer, discarding the entire process unit based on the life of the developer is very uneconomical and impractical. In particular, in the cleaning-free process in which cleaning and development are started simultaneously in the developing device, which has been recently noticed, the life of the photosensitive member is further extended, so that the developing device and the photosensitive drum have to be separated and formed as separate units. This goes against the maintenance workability improvement desired by the user and reduces the commercial value even if the non-cleaning process is adopted.

[Purpose of device]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems of the prior art, and is a dry two-component developer that has a significantly extended life, reduces the running cost of an applied image forming apparatus, and improves its maintenance workability. It is an object of the present invention to provide a developing device using the.

[Key points of device]

In order to achieve the above object, the present invention stores a two-component developer consisting of a toner and a carrier, and imparts an appropriate amount of the toner to a latent image formed on an image carrier to visualize the latent image. In a developing device having a developing chamber for storing toner and a toner replenishing chamber for storing toner to be replenished to the developing chamber, an unused device which is connected to the developing chamber through the first communication port and is to be put into the developing chamber is used. A developer storage chamber that stores a developer, a first lid member that can be opened and closed between an open position that opens the first communication port and a closed position that seals, and that is placed in the closed position when the apparatus body is not in use, An urging member for urging the first lid member to the closed position, and a developer collecting chamber that is connected to the developing chamber via a second communication port and collects and stores the developer in the developing chamber,
A second lid member that can be opened and closed between a first position that opens the second communication port and a second position that closes the second communication port and that is placed in the second position when the apparatus body is not in use, and can engage with the first lid member. A first operating rod and a second operating rod engageable with the second lid member, and a first operating position when the apparatus main body is not in use and a second operating position displaced from the first operating position. An operating lever that can be swung freely, and when the operating lever is operated from the first operating position to the second operating position, the first operating rod has the first operating lever.
When the lid member is displaced with the closed position, the second operating rod moves the second lid member to the first position, and then the operation lever is re-operated to the first operation position, The first operating rod moves the first lid member to the open position against the urging force of the urging member, and at the same time, moves the second lid member to the second position.
When the operating rod is arranged to move the second lid member to the second position and the operating lever is in the second operating position, the used developer in the developing chamber is replaced with the developer. Means for operating the recovery chamber to recover the second communication port, opening the second communication port, recovering the used developer into the developer recovery chamber, and closing the second communication port at the same time. The developer in the developing chamber can be exchanged by introducing unused developer into the developing chamber from the developer storing chamber by opening one communication port in order. It is a thing.

[Example of device]

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is a perspective view showing a developing unit U _D and its operating mechanism O _M as one embodiment of the present invention, and FIGS. 2 (a) and 2 (b).
4 (a) and 4 (b) are schematic cross-sectional views and side views showing the states of the inside of the developing unit U _D and the operating mechanism O _M at the respective operation stages. Further, FIG. 5 is a schematic diagram showing the overall configuration of an electrophotographic optical writing printer to which the developing unit U _D and the operating mechanism O _M are applied.

In FIG. 5, the photoconductor drum 1 is rotatably supported at approximately the center of the printer, and is driven and rotated at a predetermined speed in the arrow direction. In the vicinity of the peripheral surface of the photosensitive drum 1, along the rotation direction thereof, a charger 2 that uniformly charges the peripheral surface of the photosensitive drum 1 to a predetermined polarity, and input information is input to the uniformly charged peripheral surface of the drum. An optical writing head 3 that irradiates a corresponding optical signal to form an electrostatic latent image, a developing device 4 that applies toner to the electrostatic latent image to visualize the toner image, and a toner image that is sent from a paper feeding unit described later. A transfer charger 5 for transferring to the supplied transfer paper is sequentially arranged, and an electrophotographic process section R is formed. In the usual electrophotographic process, the cleaner 6 is disposed at the position indicated by the chain double-dashed line, but in this example, the developing device 4 employs a non-cleaning process which doubles as a cleaner, and the cleaner 6 is omitted. Has been done.

A fixing unit F is disposed on the left side of the electrophotographic process unit R in the figure, and in this example, the transfer paper on which the toner image has been transferred is heated and fixed while being pinched between the heating roll 7 and the pressure contact roll 8. To do. Above the fixing unit F, a face-down (image-side down) discharge tray unit formed by utilizing the upper surface of the machine body by guiding the transfer paper that has been fixed and inverting it
A transfer paper discharge path 9 for discharging onto E ₁ is formed.
In addition, E ₂ is a paper discharge tray for stacking the transfer paper, which has been fixed, in a face-up state (image surface is up) without inverting.

At the lower right of the electrophotographic process unit R in the figure, a paper feed cassette
A paper feed unit I into which 10 is inserted is formed. Paper feed unit I
Is a paper feed roller 11 for feeding the transfer paper p stacked and stored in the paper feed cassette 10, a slip roll pair 12, and a resist plate 13.
Is formed of a standby paper feed unit or the like that feeds the transfer paper p fed by the paper feed roller 11 to the transfer unit at a timing synchronized with the image formed on the photosensitive drum 1. There is.

In the printer of this example, the upper fuselage B ₁ is aligned with the lower fuselage B ₂
The optical writing head 3 has a so-called shell open structure that rotates around 14 and is opened and closed with the dividing line L as a boundary.
And the guide plate that forms the transfer paper discharge path 9 is the upper body.
Fixed to B _1, moves together with the open top body B ₁ as shown by two-dot chain line. Further, as the electrophotographic processing section photosensitive drum 1 and the charger 2 is drum unit U _P of R, the developing device 4 as a developing unit U _D, is freely unitized removable from the predetermined portion of each lower body B ₂ ing.

Here, the construction of the developing device unit U _D and its operating mechanism O _M in the present embodiment will be described with reference to FIGS. 1, 2 (a) and 2 (b). In FIG. 2 (a),
A toner replenishing chamber 15 in which the replenishment toner t is stored is defined above the developing unit U _D. The upper opening 15a of the toner replenishing chamber 15 is covered with a cover 16, and replenishment toner t is introduced from the opening 15a by opening the cover 16. Adjacent to the toner replenishment chamber 15, a developer storage chamber 17 in which an exchanged developer d ₀ in which unused toner and carrier are mixed is stored is defined.

A developing chamber 18 for temporarily storing and agitating the developer d to be used for developing is defined below the both chambers 15 and 17. The developing chamber 18 includes a developing sleeve 19 and a stirring roll.
20 are respectively arranged so as to be rotatable in the direction of the arrow. The developing sleeve 19 is an opening facing the photosensitive drum 1 in the developing chamber 18.
About 18% of the peripheral surface is supported so as to project from 18a, and above the peripheral surface, a doctor blade 21 is vertically supported with its tip in close proximity, and the layer thickness of the developer to be conveyed to the developing position D. Regulate. Further, a photosensor 22 for toner concentration detection is fixed to the casing 4a on the side opposite to the opening 18a of the developing chamber 18, and the toner concentration is detected through a detection hole 18b sealed with a transparent member.

A toner replenishing roll 24 is provided at a communication port 23 between the developing chamber 18 and the toner replenishing chamber 15, and the replenishment toner t is supplied to the developing chamber 18 by being appropriately driven according to the toner concentration detection result of the photosensor 22. The toner concentration of the developer d is maintained and maintained within a predetermined range. A partition plate is provided between the developing chamber 18 and the developer storage chamber 17.
25 is rotatably provided. The partition plate 25 is one side end portion is fixed to the rotary shaft 26, rotary shaft 26 is rotatably supported at both ends on the side casing of the developing unit U _D. Then, one end of the rotary shaft 26 is projected to the outside as shown in FIG. 1, and the lever 27 is fixed. lever
One end of a torsion spring 28 externally inserted to the rotary shaft 26 is locked to the 27, and the other end of the torsion spring 28 is locked to a pin 29 provided upright on the side casing 4b. The torsion spring 28 urges the lever 27 to rotate in the clockwise direction, and thus urges the partition plate 25 to rotate in the clockwise direction, and holds the developer storage chamber 17 in the closed position. .

Thus, in the lower part of the developing chamber 18, a developer collecting chamber 30 for collecting the used developer is defined. A scraper 32 for the developing sleeve 19, which also serves as a lid of the communication port 31, is rotatably provided at the communication port 31 of the developer recovery chamber 30 and the development chamber 18. The scraper 32 has a rotary shaft 33 at one side end.
Both ends of the rotary shaft 33 are rotatably supported by the side casings. The rotary shaft 33 is similar to the rotary shaft 26,
As shown in FIG. 1, one end is projected from the side casing 4b to form a prismatic portion 33a. The shaft 34 projecting in the vicinity of the prismatic portion 33a is a bearing shaft of the developing sleeve 19,
It also serves as a guide positioning member when inserting the developing unit U _D. A drive transmission unit is provided on the other side casing (not shown).

Here, a description will be given of an operation mechanism O _M operating orderly the partition plate 25 and the scraper 32 described above.

The operation mechanism O _M of this example is provided on the side of the space in which the developing device unit U _D of the lower machine body B ₂ is inserted. Operating mechanism
O _M includes a control lever 35, a partition plate operating rod 36 for operating the partition plate 25, and a scraper operating rod 37 for operating the scraper 32. The operation lever 35 is rotatably supported by a machine body frame (not shown) via a support shaft 38 provided upright in a substantially central portion thereof. An operation portion 35a is formed at one end of the operation lever 35, and the other end portion is bifurcated, and the branch portion 35b,
A partition plate operating rod 36 and a scraper operating rod 37 are rotatably connected to 35c, respectively. The partition plate actuating rod 36 has a curved distal end, is rotatably connected to the branch portion 35b by a shaft 39, and has a coil spring 40 suspended between these two members. In this case, the partition plate operating rod 36 has the branch portion 35.
A stopper mechanism is formed at the joint so that it cannot be rotated counterclockwise from the state where it is joined in a straight line with b. Therefore, when no external force acts on the partition plate operating rod 36, the partition plate operating rod 36 is held in a straight line posture as shown in the drawing.

On the other hand, the scraper operating rod 37 is connected to the elongated hole 37a formed at one end thereof by allowing the shaft 35d standing on the branch portion 35c to movably pass therethrough, and the coil spring 41 between these members 37, 35c.
Is suspended. A support shaft 42 is erected on the other end of the scraper operating rod 37, and the support shaft 42 is rotatably supported by a machine body frame (not shown). With this connection structure, a toggle switch-like operation action of the operation lever 35 described later becomes possible. Further, a slit 37b is formed at a position where the bearing shaft 42 is erected. Slit 37b
A developing unit U _D is when it is inserted along the direction of arrow Q, as the prism portion 33a of the scraper rotary shaft 33 is naturally fitted insertion, its size and position are set. or,
When the prism portion 33a is fitted in the slit 37b, the slit 37b is positioned so that the rotary shaft 33 and the support shaft 42 are concentric with each other.
The formation position of is set. In this example, a protrusion 35e as a switch actuating portion is formed in the vicinity of the pivotal support of the operating lever 35, and a micro switch 43 (see FIG. 2 (b)) is arranged above the protruding portion 35e. It is configured to detect upward rotation.

Next, the operation procedure and operation of the developing device unit U _D and its operating mechanism O _M configured as described above will be described with reference to FIG.
Description will be given with reference to FIGS. 4 (b) to 4 (a) and 4 (b). 2 (a) and 2 (b) show a state in which the developing device unit U _D is normally mounted and the developing action is performed, and the developer storage chamber 17 and the developer recovery chamber 30 are respectively separated by a partition plate. It is closed by 25 and scraper 32. Now, it is assumed that the developer d has been used for four times, for example, four times of toner replenishment, has been used up to 20,000 prints, and the replacement time has come. In order to replace the developer, the operator opens the machine and operates the operation part 35 of the operation lever 35.
When a is held and is rotated in the counterclockwise direction indicated by the arrow as shown in FIG. 3 (b), the scraper operating rod 37 is rotated in the clockwise direction about the support shaft 42 in conjunction with this. ,
The scraper 32 is also rotated in the same direction so that its tip end is brought into pressure contact with the developing sleeve 19. At the same time, the projection 35e of the operation lever 35 comes into contact with the micro switch 43 to turn it on.

On the other hand, the partition plate operating rod 36 moves with the upward rotation of the operation lever 35 and abuts and engages with the lever 27, and the lever 27 does not rotate, so the reaction force thereof resists the biasing force of the coil spring 40. Start to rotate clockwise. Further, when the operation lever 35 is further rotated, the curved tip end surface slides along the tip end surface of the lever 27, and when the engagement is released, the biasing force of the coil spring 40 causes a counterclockwise direction. Then, it returns to its original straight posture. That is, the partition plate operating rod 36
Moves into the lower side (shown by the chain double-dashed line) from the upper side of the lever 27 as the operating lever 35 rotates upward. Incidentally, when the operation lever 35 is rotated, the resistance is comparatively large up to the middle because the coil spring 41 is rotated against the tensile elasticity of the coil spring 41, but the dead point (the coil spring 41 extends on the shaft 35d). (The state in which the pressure is applied), the biasing direction of the coil spring 41 is changed and rotated without resistance, and is held in the posture shown in FIG. 3 (b).

When the micro switch 43 is turned on, as shown in FIG. 3 (a), this signal is received and the developing sleeve 19 and the stirring roll are received.
Only 20 is driven and rotated for a predetermined time. During this time, the scraper 32 scrapes off the used developer d carried on the developing sleeve 19 and conveyed, and is surely collected in the developer collecting chamber 30 from the communication port 31 opened below.

Next, the operator, after confirming that the developer recovery is completed, for example, on an operation panel (not shown) or the like, reversely rotates the operation lever 35 downward (clockwise direction). As a result, as shown in FIG. 4 (b), the operating lever 35 and both operating rods 36, 3 are
7 returns to the original position shown in FIG. 2 (b). At this time, the partition plate operating rod 36 abuts and engages with the lever 27 and receives a reaction force. However, since it does not rotate in the counterclockwise direction due to the above-mentioned stopper structure, the lever 27 is not biased by the torsion spring 28. Forcibly rotate counterclockwise against. As a result, as shown in FIG. 4A, the partition plate 25 rotates counterclockwise to open the developer storage chamber 17, and the replacement developer d ₀ is introduced into the development chamber 18. . Thus, the developing unit U
_D will be able to print again 20000 sheets.

And as described above, the developing device because the lifetime of the unit U _D extends doubled as compared with the conventional developing unit, sufficiently cope greatly the life of the photosensitive drum 1 which extends by adopting cleaning without process, replacing the drum unit U _P and the replacement of the developing unit U _D can be set to the same one time. Therefore, the running cost can be reduced, and the maintenance workability of the printer can be significantly improved.

It should be noted that the present invention should not be limited to the above specific embodiment, and various modifications can be made within the technical scope of the present invention. For example, the replenishment developer d ₀
The present invention can also be applied to the case where only the carrier is used, and when the used developer is charged at the same time as new toner, initial mixing is performed to prepare for normal operation. Further, a system may be adopted in which an input port is provided in the developer storage chamber and the replacement developer is repeatedly input, and in this case, the life of the developing device unit U _D can be extended three times or more. Further, the operating mechanism O _M may be installed on the side of the developing device unit U _D.

[Effect of device]

As described above in detail, according to the present invention, the developing unit is provided with the developer storage chamber and the developer recovery chamber, and
The life of the developing unit can be significantly extended by controlling the opening and closing of each of these chambers in a predetermined order. As a result, the running cost of the image forming apparatus to which the developing unit is applied can be significantly reduced, and the maintenance workability can be significantly improved. In particular, the present invention can be applied to an image forming apparatus that employs a non-cleaning process and has a developing unit and a drum unit as one unit, but the above effect becomes more remarkable.

[Brief description of drawings]

FIG. 1 is a perspective view showing a developing unit U _D and its operating mechanism O _M as one embodiment of the present invention, and FIGS. 2 (a) and (b) to FIGS. 4 (a) and (b) are Schematic cross-sectional views and side views showing the states of the inside of the developing unit U _D and the operating mechanism O _{M at} the respective operation stages, and FIG. 5 shows the developing unit U _D.
FIG. 6 is a schematic view showing the overall structure of an electrophotographic optical writing printer to which the operating mechanism O _M is applied, and FIG. 6 is a schematic sectional view showing a conventional developing device unit. 1 ... photoconductor drum, 15 ... toner supply chamber, 17 ... developer storage chamber, 18 ... developing chamber, 25 ... partition plate, 30 ... developer recovery chamber, 32 ... scrapers, O _M ... operating mechanism, U _D ... development Unit,

Claims (1)

[Scope of utility model registration request] 1. A developing chamber for storing a two-component developer comprising a toner and a carrier and applying the appropriate amount of the toner to a latent image formed on an image carrier to visualize the latent image. A developing device having a toner replenishing chamber for storing toner to be replenished in the developing chamber, wherein the developing chamber is connected to the developing chamber via a first communication port and stores unused developer to be introduced into the developing chamber. An agent storage chamber, a first lid member that is openable and closable between an open position that opens the first communication port and a closed position that seals, and that is placed in the closed position when the apparatus body is not in use; An urging member for urging to the closed position, a developer collecting chamber that is connected to the developing chamber via a second communication port and collects and stores the developer in the developing chamber, and opens the second communication port. It can be opened and closed between the first position to close and the second position to close, A second lid member that is sometimes placed in the second position, a first actuating rod that is engageable with the first lid member, and a second actuating rod that is engageable with the second lid member. The control lever is swingable between a first operation position when not in use and a second operation position displaced from the first operation position, and the operation lever is operated from the first operation position to the second operation position. At this time, the first operating rod is displaced while keeping the first lid member in the closed position, the second operating rod moves the second lid member to the first position, and then the operating lever is moved to the first position. When re-operated to the first operation position, the first operating rod moves the first lid member to the open position against the urging force of the urging member, and at the same time, the second operating rod moves to the second operative position. The interlocking mechanism arranged to move the lid member to the second position, and the operation lever are the second Means for activating the used developer in the developing chamber to collect it in the developer collecting chamber when in the operating position; opening the second communication port; collecting the used developer; The collection into the chamber, the opening of the first communication port at the same time as the closing of the second communication port, and the introduction of the unused developer from the developer storage chamber into the developing chamber are performed in order. Therefore, the developer in the developing chamber can be exchanged.