JPS62237475A - Developing device - Google Patents

Abstract

PURPOSE:To prevent a developing roller from rotating in reverse at the time of attachment and detachment, and to prevent a toner from overflowing between the roller and a photosensitive body, by constituting the titled device so that a rotary sleeve for constituting the developing roller rotates in only one direction of the normal direction. CONSTITUTION:A developing mechanism part 40 is provided with a developing roller 41 opposed and faced to the first aperture 31a opened so as to face a photosensitive body 10 side of the lower casing unit 31, and the developing roller 41 consists of a magnetic roller 42 having plural pieces of magnetic pole parts, and a rotary sleeve 43 fitted externally to the magnetic roller 42 and rotates in the reverse direction against the rotational direction (b) of the photosensitive body 10. The rotary sleeve 43 is in what is called a with-mole in which a development processing is performed by making a developer magnetic brush D for sticking to the surface slide-contact in the direction which follows the movement of an electrostatic latent image formed on the photosensitive body 10. On the upper face part side of the developing roller 41, a doctor 44 for controlling the thickness of the developer magnetic brush D is installed, and the developer magnetic brush D whose thickness is controlled by the doctor 44 is leveled to a smooth state by a sheet member 45.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a developing device installed in an image forming apparatus such as an electronic copying machine.

(Prior Art) Conventionally, in this type of image forming apparatus such as an electronic copying apparatus, as shown in FIGS. 11 and 12, a developing device main body 30 has a lower casing unit 31 and an upper casing unit 32. The developing mechanism section 40 and the developer agitating section 5 are assembled into one piece, and are disposed within the lower casing unit 31.
0 built-in, and in the loading space 61 formed in the upper casing unit 32 of the developing device main body 30,
A toner cartridge 80 containing a developer (hereinafter referred to as toner) is removably loaded therein.

The developing device main body 30 as described above is removably installed in the storage space of the image forming apparatus, and the developing roller 4 of the developing mechanism section 40
1 is positioned opposite to a photoreceptor 10 which is an image carrier.

The developing roller 41 includes a magnetic roll 42 having a plurality of magnetic pole parts, and a rotating sleeve 43 that is fitted around the magnetic roll 42 and rotates in a direction opposite to the rotational direction of the photoreceptor 10. This rotating sleeve 43 has a developer magnetic brush D attached to its surface.
The developing roller 41 is in a so-called "width mode" in which developing processing is performed by sliding the developing roller 41 into sliding contact in a direction that follows the movement of the electrostatic latent image formed on the photoreceptor 10.
A doctor 44 for regulating the thickness of the developer magnetic brush D is installed on the upper surface side.

Further, the developer stirring unit 50 includes first and second bladed stirring rolls 51 and 52 disposed on the side of the toner supply port 33.
The first bladed stirring roll 51 reciprocates and stirs the toner T sealed in the lower casing unit 31 along the axial direction of the developing roller 41.
The bladed stirring roll 52 uniformly mixes the toner T newly supplied from the toner supply port 33.

On the other hand, the developing roller 41 has a gear provided on the rotational drive shaft side (not shown) of the rotating sleeve 43 engaged with a gear 74 that rotates in synchronization with a drive gear 71 of a replenishment drive mechanism 70 installed on the image forming apparatus main body 1 side. The drive is controlled in conjunction with the alignment.

However, in the driving force transmission means of the replenishment drive mechanism 70 installed on the image forming apparatus main body 1 side to the developing device main body 30 in such a conventional structure, the rotating sleeve 43 of the developing roller 41 has a structure that allows reverse rotation. This is the current situation.

(Problem to be Solved by the Invention) For this reason, as shown in FIG. The sleeve 43 rotates in the reverse direction A, and the toner T accumulates in front of the doctor 44. In this state, as shown in FIG. 12, when the rotating sleeve 43 is rotated in the normal direction B during the developing operation There have been problems such as an accident that the toner T overflows between the photoreceptor 10 and the photoconductor 10.

The present invention was made under the above circumstances.

An object thereof is to provide a developing device that reliably prevents reverse rotation of the developing roller in the power transmission portion when the image forming device is attached or detached.

[Structure of the Invention] (Means for Solving the Problems) In order to solve the above-mentioned problems, five aspects of the present invention provide a method for transmitting a document image placed on a document table of an image forming apparatus main body through an optical system. A rotary sleeve of a developing roller is removably engaged with a drive input system gear of the image forming apparatus main body to interlock with an electrostatic latent image formed on a uniformly charged image carrier. In this developing device, the developing device is configured to supply developer and perform adhesion development using a transmission drive means according to the present invention, in which the rotary sleeve is rotatable in only one normal direction.

(Function) In other words, the present invention has the above configuration,
Since the rotating sleeve that makes up the developing roller rotates only in one normal direction, the developing roller does not rotate in the opposite direction when it is installed or removed, which prevents toner from overflowing between it and the photoreceptor. This can be reliably prevented.

(Example) Hereinafter, an example of the present invention will be described in detail with reference to the drawings shown in FIGS. 1 to 9. In addition.

In the illustrated embodiment of the invention, FIGS.
The same reference numerals will be used to describe the same parts in the attachment ring portion of the conventional developing device main body shown in FIG. 2 to the image forming apparatus.

FIG. 1 shows the external appearance of an electronic copying apparatus which is an image forming apparatus equipped with a developing device according to the present invention, and numeral 1 in the figure indicates the main body of the copying apparatus. A paper feed cassette 2 capable of automatic or manual paper feeding is mounted on the right side of the copying apparatus main body 1, and a paper discharge tray 3 is mounted on the left side.

A document table 4 that is movable back and forth in the left-right direction (direction of arrow a) is provided on an upper document placement plate on which a document (not shown) is placed. Note that 5 in the figure is an operation display section provided on the front edge of the upper surface of the copying apparatus main body 1, including a display 6, a numeric keypad 7,
It consists of an exposure setting volume 8, a print key 9, etc.

Next, the internal mechanism of the copying apparatus main body 1 will be explained with reference to FIG.

In the figure, reference numeral 10 denotes a drum-shaped photoreceptor as an image carrier rotatably supported approximately at the center of the main body 1 of the copying apparatus.
It can be rotated in the direction of the arrow in synchronization with the document table 4 by a drive mechanism (not shown). The photoreceptor 10 is uniformly charged by a charging charger 11, and an original image irradiated by an exposure lamp 12 is transferred onto the photoreceptor 10 by a focusing light transmitter (Selfoc lens array) 13 constituting an optical system device. An electrostatic latent image is formed by forming an image, and toner T is supplied and adhered to this electrostatic latent image by a developing device main body 30, which will be described later, to develop it.

This developer image (hereinafter referred to as a toner image) is sent to the transfer charger 14 side.

The transfer charger 14 transfers a toner image onto copy paper P made of plain paper as recording paper fed from a paper feed cassette 2 that is automatically or manually fed via a paper feed roller 15 and a pair of registration rollers 16 and 16. After the transfer, the copy paper P is peeled off from the photoreceptor 10 by a peeling charger 17 using AC corona discharge, passed through a conveyance path 18, and the toner image is melted and fixed by a fixing device 19, and transferred to a pair of discharge rollers 20. .20, the paper is discharged onto the paper discharge tray 3.

Photoreceptor 10 after transfer and peeling of toner image onto copy paper P
The residual toner on the photoreceptor 10 is cleaned by a cleaning device 21, and the electric potential on the photoreceptor 10 is lowered to a certain level or less by a static elimination lamp 22 to make the next copying operation possible.

Further, in the upper surface portion of one side corresponding to the lower surface of the document table 4 of the copying apparatus main body 1, there is a storage space which becomes a mounting portion of a developing device main body 30, which will be described later and is mounted so as to face the photoreceptor 10. 100 is formed, and this storage space 1
A protective cover 101 is provided on the upper opening side of 00 so as to be openable and closable.

The developing device main body 30 has a structure as shown in detail in FIGS. 3 to 7.

That is, this developing device main body 30 is formed by assembling and integrating a lower casing unit 31 and an upper casing unit 32, and the lower casing unit 31 has a built-in developing mechanism section 4o and a developer stirring section 50. There is.

As shown in FIG. 3, the developing mechanism section 40 includes a developing roller 41 facing a first opening 31a of the lower casing unit 31 facing the photoreceptor 10 side. The developing roller 41 includes a magnetic roll 42 having a plurality of magnetic pole parts, and a rotating sleeve 43 that is fitted around the magnetic roll 42 and rotates in a direction opposite to the rotational direction of the photoreceptor 10. This rotary sleeve 43 develops by sliding the developer magnetic brush D attached to its surface in a direction that follows the movement of the electrostatic latent image formed on the photoreceptor 10. The processing is carried out in a so-called "width mode".A doctor 44 for regulating the thickness of the developer magnetic brush D is installed on the upper surface side of the developing roller 41, and the doctor 44 regulates the thickness. The developed developer magnetic brush D is attached to the thin plate member 4
5 to smooth it out.

Further, the developer stirring section 50 includes first and second bladed stirring rolls 51 and 52 facing oppositely to the second opening 31b opened at the upper part of the lower casing unit 31, which serves as a toner supply port. Equipped with.

The first bladed stirring roll 51 transfers the toner T sealed in the lower casing unit 31 to the developing roller 41.
The second bladed stirring roll 52 uniformly mixes the toner T newly supplied from the second opening 31b serving as the toner supply port. ing.

On the other hand, the above-mentioned upper casing unit 32 has a loading space 61 having a hopper-like cross-sectional shape, and an opening 32a located at the inner bottom thereof corresponding to the second opening 31b of the lower casing unit 31. These openings 31b and 32a form a toner supply port 33.

In the loading space 61, a toner cartridge 8o having a structure described later and having a toner T sealed therein is removably loaded from above in a cassette manner, and a toner supply opening is provided at the inner bottom of the toner cartridge 8o. Mouth 8
A supply roller 82 is installed near 1.゛This toner cartridge 80 has both ends of a rotating shaft 83 of the supply roller 82 protruding outside, and a gear 84 of this rotating shaft 83 is attached to a drive gear 68 of a drive system to be described later. The side end portion 83a is
As shown in the figure, the clip-shaped shaft support 63 provided on one side wall of the loading space 61 is elastically fitted in the same way as in the conventional structure, and as shown in FIG. 84 is meshed with a drive gear 68 driven by a replenishment drive mechanism 7o, which will be described later. The drive is controlled by a detection signal from the device 69.

That is, as shown in FIG. 6, the replenishment drive mechanism 70 described above is composed of a driven gear 73 to which the driving force of a driving gear 71 is transmitted via a clutch 72, and the toner cartridge is connected to the driven gear 73. A drive gear 6, which is a means for transmitting the driving force of the developer replenishment mechanism, meshes with a gear 84 attached to the drive side end 83a of the supply roller rotation shaft 83 of 80.
A drive signal to the clutch 72 is sent in response to a detection signal from the developer concentration detector 69.

Further, a drive transmission gear 75 and a first . Second
The rotational driving force of the developer stirring roller 51, 52 is transmitted to the gear group 76, 77.

As shown in FIG. 7, a drive input system gear 7 rotates integrally with a drive gear 71 installed on the image forming apparatus main body 1 side.
It is designed to be interlocked with 4.

Further, as shown in FIGS. 8 and 9, the rotating shaft 46 of the rotating sleeve 43 and the drive transmission gear 75 constituting the developing roller 41 of the developing mechanism section 40 have concave and convex tooth portions 91 and 92 of each other. Ratchet fitting is performed, and the drive transmission gears 75 are always pressed and biased in the mutual fitting direction by the biasing force of the coil spring 93, so that they follow the normal rotation direction B in the same direction. On the other hand, in the reverse direction A, the ratchet engagement is released against the biasing force of the coil spring 93, as shown by the two-dot broken line in FIG. By idling the rotation sleeve 75, reverse rotation of the rotary sleeve 43 can be prevented.

FIG. 10 shows another embodiment of the present invention, which employs a so-called one-way clutch in which the rotating shaft 46 of the rotating sleeve 43 and the drive transmission gear 75 are connected by a coil spring 94.

This coil spring 94 has an end 94a on the side of the drive transmission gear 75 locked in a recess 75a formed on the outer periphery of the drive transmission gear 75, and the first turn thereof is narrowed to a smaller diameter than the other coil springs. has been done. That is,
In the driving operation of such a one-way clutch, when the drive transmission gear 75 rotates in the normal rotation direction B, the coil spring 94 rotates together with the drive transmission gear 75, and the inner diameter of the coil spring 94 is reduced so that the rotation shaft portion of the rotation sleeve 43 At the same time, the rotation sleeve 43 is allowed to rotate in the normal rotation direction B due to the increase in frictional force at this time. On the other hand, when the drive transmission gear 75 rotates in the reverse direction, the inner diameter of the coil spring 94 becomes larger and its frictional force becomes smaller than the rotational torque of the rotating sleeve 43, causing the drive transmission gear 75 to idle.

This makes it possible to prevent the rotating sleeve 43 from rotating in the opposite direction.

Therefore, the developing mechanism section 40 of the developing device main body 30 is
First, during installation, when the drive transmission gear 75 is engaged with the drive input system gear 74 that rotates together with the drive gear 71 installed on the image forming apparatus main body 1 side, even if the drive transmission gear 75 rotates in the reverse direction. The rotary sleeve 43 does not rotate, so that the rotary shaft 46 of the rotary sleeve 43 can remain stationary so as not to rotate in the opposite direction during installation. Further, when the drive transmission gear 75 rotates in the regular forward rotation direction B, the rotation sleeve 4 follows the rotation.
This allows the rotating shaft 46 of No. 3 to rotate.

It should be noted that the present invention is not limited to the above embodiments, and it goes without saying that various modifications can be made without departing from the gist of the present invention.

[Effects of the Invention] As is clear from the above description, according to the present invention, the drive generated by the engagement between the rotating shaft of the rotating sleeve of the developing roller and the drive transmission gear during the attachment/detachment operation to the image forming apparatus. Since the rotating sleeve is prevented from rotating in any direction other than the normal direction as the transmission gear rotates, the developing roller does not rotate in the opposite direction when it is attached or detached, unlike in the conventional case, so toner does not overflow between it and the photoreceptor. Therefore, it is possible to provide a developing device that has an excellent effect of reliably preventing the above problems.

[Brief explanation of drawings]

FIG. 1 is an external perspective view showing an embodiment of an electronic copying apparatus as an image forming apparatus using the developer replenishing device according to the present invention, FIG. 2 is a schematic cross-sectional view showing the internal structure, and FIG. 4 to 7 are explanatory diagrams showing the main parts of the developing device main body, and FIG. 8 is a drive of the rotating sleeve of the developing roller in the developing device main body of the present invention. FIG. 9 is an explanatory diagram schematically showing the rotational engagement and disengagement state of the drive transmission portion, and FIG. 10 is a sectional view of the drive transmission portion showing another embodiment of the present invention. The schematic explanatory drawings, FIGS. 11 and 12, are schematic sectional views showing a state in which a developing device main body is attached to a conventional electronic copying apparatus. 1... Image forming apparatus main body, 4... Original table, 10
...image carrier, 13...optical system, 30.
...Developing device main body, 41...Developer roller, 43...Rotating sleeve, 46...Rotating shaft, 70
...Replenishment drive mechanism. 74... Drive input system gear, 75... Drive transmission gear, 91.92... Uneven tooth portion, 93... Elastic member (coil spring). A: Reverse direction, B: Forward direction. T...Developer. Applicant's Representative Patent Attorney Takehiko Suzue Figure 3 Figure 4 Figure 4b Figure J15 Figure 6 Figure 8 Figure 12 Procedure Nefi Official Book May y, 1986

Claims (3)

[Claims] (1) The original image placed on the original platen of the main body of the image forming apparatus is imaged on a uniformly charged image carrier through an optical system, and the electrostatic latent image is formed. In a developing device in which developer is supplied and developed by a transmission drive means using a rotating sleeve of a developing roller which is removably engaged with a drive input system gear of a forming device main body and interlocked with each other,
A developing device characterized in that the rotating sleeve is rotatable only in one normal direction. (2) The developing device according to claim 1, wherein the rotating sleeve and the drive transmission gear of the rotating shaft are removably ratchet-fitted via an elastic member. (3) The developing device according to claim 1, wherein the rotating sleeve and the drive transmission gear of the rotating shaft are enabled to follow each other by means of a coil spring.