JPS62178281A - Image forming device - Google Patents

Abstract

PURPOSE:To improve the accuracy of a gap between an image carrier and a developing roller with a simple constitution by fitting guide members for directly guiding both the end parts of the shaft of the developing roller to body frames on which an image carrier is arranged. CONSTITUTION:Both the end parts 33c of the developing roller 33 projected from a developing device body are directly guided by the guide parts 65a of the guide members 65. These guide members 65 are fixed under the status that positioning projection parts 81 are engaged with respective positioning holes 83 formed on the body frames 82. Holes 84 to which the shaft of a photosensitive body 6 is inserted and fixed so as to be positioned are formed on the body frames 82 and the developing device 9 loaded to the part to be loaded is automatically positioned to the photosensitive body 6, so that non-adjustment can be attained and high positioning accuracy can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Objective of the Invention] (Industrial Field of Application) The present invention relates to an image forming apparatus such as an electronic copying machine, and particularly relates to an image forming apparatus having a developing roller. The present invention relates to an improvement in an image forming apparatus in which the apparatus can be freely inserted into and removed from a mounting portion formed opposite to a placement portion of an image carrier in an image forming apparatus main body.

(Prior Art) In recent years, in image forming apparatuses such as copying machines, a developing device is configured to be able to be inserted into and removed from a mounting portion formed in the main body of the image forming apparatus, and the developing device accommodates developers of different colors. A device that can be exchanged as appropriate has been put into practical use.

However, in conventional image forming apparatuses of this type,
The developing device is positioned relative to the main body frame indirectly by supporting the developing device main body portion via a separate bracket.

(Problems to be Solved by the Invention) For this reason, there are problems in that the positional accuracy of the developing device is poor, and the gap between the image bearing member such as a drum-shaped photoreceptor and the developing roller is not sufficiently accurate and adjustment is difficult.

The present invention has been made based on the above-mentioned circumstances, and its purpose is to enable easy and reliable positioning of the developing device while having a simple configuration, and to improve the accuracy of the gap between the image carrier and the developing roller. It is an object of the present invention to provide an image forming apparatus that can improve the image forming apparatus and eliminate the need for adjustment.

[Structure of the Invention] (Means for Solving the Problems) In order to solve the above-mentioned problems, the present invention provides a developing device having a developing roller in a portion where an image carrier is disposed in an image forming apparatus main body. In an image forming apparatus that can be freely inserted into and removed from mounting portions formed to face each other, both ends of the shaft of the developing roller of the developing device protrude from a main body of the developing device;
Both ends of the shaft of the developing roller are directly guided by shaft guide portions of a guide member disposed in the mounting portion, and the guide member is attached to the main body frame to which the image carrier is attached.

(Function) In other words, the present invention maintains the positional accuracy of this guide member with respect to the main body frame by directly attaching the guide member to the main body frame to which the image carrier is attached, and furthermore, the shaft guide portion of this guide member allows the development By directly guiding both ends of the roller shaft that protrude from the developing device main body, the positional accuracy between the developing roller and the guide member can be maintained. positioning can be performed easily and reliably, improving the accuracy of the gap between the image carrier and the developing roller, and eliminating the need for adjustment.

(Example) Hereinafter, an example of the present invention will be described with reference to the drawings. FIG. 2 is a schematic longitudinal sectional front view of a copying apparatus as an image forming apparatus, and its configuration is as follows.

In the figure, reference numeral 1 denotes a copying apparatus main body as an image forming apparatus main body.A document table 2 is provided on the top surface of the copying device main body 1 so as to be able to freely move back and forth, and an operation panel is provided on the front edge of the top surface. ing.

Further, a paper feed cassette 3 is attached to the right side of the copying apparatus main body 1, and a cassette cover 4 of the paper feed cassette 3 serves as a manual paper feed table 5 for manually feeding paper P as appropriate.

A drum-shaped photoreceptor 6 serving as an image carrier is provided approximately at the center of the copying apparatus main body 1, and a charging device 7. Exposure device 8. Phenomena device 9. Transfer device 10
．． Peeling device 11. and a cleaning device 12 are arranged in this order.

Further, in the lower part of the main body 1 of the copying machine, paper P supplied from an automatic paper feeder 15 equipped with a paper cassette 3 and paper P supplied from a manual paper feed tray 5 are connected to the photoreceptor 6. A w1m feed path 18 is formed which leads to a paper discharge tray 17 provided on the left side of the main body 1 of the copying apparatus 1 through an image transfer section 16 between the image transfer unit 10 and the transfer device 10 .

Further, a pair of aligning rollers 20 is arranged on the upstream side of the image transfer section 16 of the paper transport path 18, and a fixing device 21 and a pair of paper discharge rollers 22 are arranged on the downstream side.

During the copying operation, the photoreceptor 6 is driven in the direction of the arrow (clockwise in the state shown in FIG. 2) by a drive mechanism (not shown) in synchronization with the movement of the document table 2, and the exposure device 8 is driven to expose the photoreceptor 6. The lamp 23 lights up. First, it is uniformly charged by the charging device 7, and then the exposure device 8
As a result, the original image set on the original platen 2 is imaged onto the photoreceptor 6, and an electrostatic latent image thereof is formed. Next, this electrostatic latent image on the photoreceptor 6 is sent as a developer image to the transfer device 10 side by a developing device 9 that uses a two-component edge agent consisting of toner a and carrier b.

On the other hand, a sheet P that is automatically or manually fed is fed through a pair of aligning rollers 20, and the developer image previously formed on the photoreceptor 6 is transferred to the sheet P by the action of the transfer device 10.
transcribed into. Then, the paper P is peeled off from the photoreceptor 6 by a peeling device 11 using AC corona discharge, passes through a conveyance path 18, and is sent to a fixing device. Here, after the developer image is fused and fixed on the paper P, it is discharged onto the paper discharge tray 17 by a pair of paper discharge rollers 22 .

Note that after the developer image is transferred onto the paper P, the residual toner remaining on the photoreceptor 6 is cleaned by the cleaning device 12, and the next copying operation is ready.

The developing device 9 has a structure as shown in detail in FIGS. 3 to 8.

That is, the developing device 9 includes a lower unit 30a and an upper unit 30b, and the lower unit 30a includes a developing mechanism section 31 and a developer stirring section 32.

The mechanism section 31 includes a developing roller 33 disposed facing the opening 41 in the lower casing 408 of the developing device main body 40, and a developer magnetic brush D' formed on the surface of the developing roller 33. A developer magnetic brush D is provided at the sliding contact portion with the photoreceptor 6, that is, upstream of the development position 34.
1, and a thin plate member 36 for leveling the developer magnetic brush D' whose thickness is regulated by the doctor 35. Further, the developer stirring section 32 is
The first and second developer stirring bodies 38 are accommodated in the developer accommodating portion 37 in the upper casing 40b of the device main body 40.
It has 39.

The surface development roller 33 includes a magnetic roll 33a having five magnetic poles, and a rotating sleeve 33b fitted around the magnetic roll 33a and rotating counterclockwise in the figure.

The rotary sleeve 33b is in a so-called with mode in which it rotates counterclockwise in the figure to perform development, and slides the developer brush D' held on its surface in a direction that follows the flow of the image on the photoreceptor 6. By bringing them into contact with each other, sufficient development time is ensured, and the electrostatic latent image formed on the photoreceptor 6 is developed in a high-quality image state.

Further, the upper unit 30b includes an upper casing 40b of the developing device main body 40, a toner hopper 50 that is detachable from the upper casing 40b, and a developer concentration for detecting the developer concentration in the developer storage section 37. Detector 51 (
In the case of a color developer, this is installed at a position 51' shown by the two-dot chain line in FIG.
Replenishment device driving means 53 that drives the replenishment roller 52 incorporated in the toner hopper 51 as necessary.
It has a configuration that incorporates the following.

Further, as shown in FIGS. 4 and 5, the upper unit 30b has a plurality of screws 54 and 54 attached to the lower unit 30a.
. . , so that the front side and the rear side are fixed and integrated, and can be lifted via a handle 60 attached to the upper unit 30b.

Further, the developing device 9 configured as described above is formed in the copying machine main body 1 through an opening 61 for inserting and removing the developing device formed on the upper surface side of the copying machine main body 1, as shown in FIG. The structure is such that it can be attached to and detached from the attached part. Note that in order to expose the opening 61, the upper cover 62 may be opened after sliding the document table 2.

The shaft 33C of the developing roller 33 protrudes from both ends of the developing device main body 40.
As will be described later, both ends of the shaft 3c are guided and positioned by guide grooves 65a, 65a serving as shaft guides of guide members 65, 65 disposed on the front and rear sides of the mounted portion.

Further, on the front side of the lower unit 30a, as shown in FIG. The configuration is such that the position of the magnetic pole portion facing the can be adjusted.

Further, the toner hopper 50 of the upper unit 30b is of a cartridge type, so that when the toner a runs out, the toner hopper 50 can be replaced.

The hopper guide 67 that supports the toner hopper 50 is removable, and when the hopper guide 67 is removed, the developer concentration detector 51 is removed as shown in FIG.
．． Supply ¥7! The driving means 53.degree., the control board 68, etc. are exposed.

The replenishment device driving means 53 transmits the driving force of the drive tooth ll70 to the driven gear 72 via the clutch 71, and drives the replenishment roller 52 equipped with a gear (not shown) that meshes with the driven gear 72. Further, a drive signal to the clutch 71 is sent in response to a detection signal from the developer concentration detector 51.

Further, as shown in FIG. 8, the developing roller 33. is incorporated in the lower unit 30a. The first and second developer agitating bodies 38 and 39 are interlocked with each other through gear groups 73 to 76 that mesh with each other in sequence, and the gear 74
rotates together with the drive gear 70.

The first developer agitating body 38 has blades 38a attached so as to be externally fitted obliquely to the rotating shaft 38b.
It is designed to move back and forth along the axial direction. The second developer stirring body 39 has blades 39b arranged in two rows at a phase of 180° along the axial direction of the rotating shaft 39a, and is located directly below the toner supply lower 7. The replenishing toner a is uniformly mixed with the developing agent in the developer accommodating portion 37.

Next, the structure of the guide member 65.degree. 65 disposed at the mounting portion to guide the phenomenon device 9 thus structured will be explained with reference to FIGS. 9 to 14.

The guide members 65, 65 each have a guide groove 65a as a shaft guide portion that directly guides both ends of the shaft 33c of the developing roller 33. This guide groove 6
5a is disposed asymmetrically with respect to the opening 61 for inserting and removing the developing device, and when the developing device 9 is faced to the opening 61 in the reverse direction, the end of the shaft 33c is in the guide groove 65a.
In addition, when the developing device 9 is turned in the opposite direction, the end of the shaft 33C comes into contact with the upper end side of the guide members 65 and 65, and the shaft 33C is in a stable state for further insertion. A stopper portion 65b for preventing reverse insertion is formed.

As shown in FIG. 11, if the developing device 9 is inserted in the correct direction, it can be inserted into the mounting section, and as shown in FIG. 12, if the developing device 9 is inserted in the opposite direction, it cannot be inserted. There is.

Incidentally, since the shaft 33c is located at a position shifted from the center of gravity G of the developing bag @9 as shown in FIG. 12, a stopper portion 65b for preventing reverse insertion.

When both ends of the shaft 33c come into contact with the shaft 33c, the developing roller 33 rotates in the direction of the arrow, so that the developing roller 33 does not come into contact with surrounding members.

Furthermore, as shown in FIG. 13, when the developing device 9 is inserted into the guide member 65°65 with the developing device 9 tilted in a direction different from the direction of rotation due to the action of the center of gravity G (the six directions of arrows), the developing device main body 40 and A guide portion 65 for preventing roller contact is provided at a position where the developing roller 33 and a surrounding member 80 such as a magnetic frame are in contact with each other, and a gap q is always formed between the developing roller 33 and a surrounding member 80 such as a magnetic frame to prevent direct contact. It becomes.

Further, the upper end portions of the guide members 65 and 65 each have a cover attachment portion 65d that serves as a pivot point for the upper cover 62 that opens and closes the opening 61 for inserting and removing the developing device.

The guide members 65, 65 formed in this manner are made of a non-magnetic material, and are configured to smoothly guide the magnetized shaft 33c without being attracted to it.

Further, as shown in FIG. 14, these guide members 65.65 have positioning protrusions 81.
．． They are fixed in a state where they are fitted into positioning holes 83 and 83 formed in each of the holes 83 and 82, respectively. The main body frame 82
A hole 84 is formed in which a photoreceptor shaft for positioning the photoreceptor 6 is inserted and fixed, and the guide member 65, 65
The current device 9, which is attached to the attachment part via the bracket, is automatically positioned with respect to the photoreceptor 6, and compared to the conventional position adjustment which is performed indirectly using a separate bracket, no adjustment is required. Moreover, high positional accuracy can be obtained.

Roughly speaking, as shown in FIGS. 9, 10, and 13, the upper end portion 85a of the leaf spring member 85 is interposed in the guide groove 5a serving as the shaft guide portion of one guide member 65. As a result, the developing roller 33
A bias voltage is applied to the shaft 33C, and the developing device 9 is pressed to one side by elasticity, thereby positioning the developing device 9 in the front-rear direction.

Note that the tip of the upper end 85a of this plate spring member 85 is bent outward at an obtuse angle, so that it does not interfere with the insertion of the shaft 33c, and the shaft 33c is reliably guided and its elastic force is The shaft 33c is sequentially positioned, and the shaft 33c is securely pressed against the end surface of the shaft 33c to apply a bias voltage.

Furthermore, since the guide member 65 is made of an insulating material, no insulation treatment is required between it and the main body frame 82, and since it is surrounded by the guide groove 65a, it is safer than the conventional connector type.

The developing device 9, which has been inserted to a predetermined position using the guide members 65, 65 as a guide, is inevitably positioned downward by the guide groove 65a and in the front, back, left and right directions, but upward movement is limited to the handle 6o. This is done by folding down the handle 60 and locking the hook 86 integrally formed on the handle 60 with a locking pin (not shown) disposed on the mounting portion.

At this time, the portion of the hook 86 that contacts the locking pin is wedge-shaped, and the developing device 9 is reliably pressed downward and does not float.

[Effects of the Invention] As explained above, the present invention allows a developing device having a developing roller to be inserted into a mounting portion formed opposite to a portion where an image carrier is arranged in an image forming apparatus main body. In a removable image forming apparatus, both ends of the shaft of the developing roller of the developing device protrude from a main body of the developing device, and both ends of the shaft of the developing roller are connected to a shaft of a guide member disposed in the attached portion. The image carrier is directly guided by a guide portion, and the guide member is attached to the main body frame to which the image carrier is attached. Therefore, although it has a simple configuration, it is possible to provide an image forming apparatus that allows easy and reliable positioning of the developing device, improves the accuracy of the gap between the image carrier and the developing roller, and eliminates the need for adjustment. Qin effect.

[Brief explanation of drawings]

The drawings show an embodiment of the present invention, and FIG. 1 is a schematic perspective view showing the state of the developing device when it is inserted, FIG. 2 is a schematic longitudinal sectional front view of the image forming apparatus, and FIG. A schematic front view of the developing device; FIG. 4 is a schematic perspective view showing the front side of the developing device with the toner hopper removed; FIG. 5 is a schematic perspective view showing the rear side of the developing device with the toner hopper removed;
Fig. 6 is a schematic perspective view of the upper unit and lower unit separated, Fig. 7 is a perspective view of the upper unit with the hopper guide removed, Fig. 8 is an exploded perspective view showing the drive system of the lower unit, FIG. 9 is a front view of the guide member which is the main part, FIG. 10 is an explanatory diagram showing the attached state of the leaf spring member,
Fig. 11 is a perspective view showing the state when the developing device is inserted in the correct direction, Fig. 12 is a perspective view showing the state when the developing device is inserted in the opposite direction, and Fig. 13 is a perspective view showing the state when the developing device is inserted in the opposite direction and tilted. FIG. 14 is a perspective view showing a state in which the phenomenon device is attached to the main body frame. 1... image forming apparatus main body, copying apparatus main body), 6...
Image carrier (photoreceptor), 9... Developing device, 33... Developing roller, 33a... Shaft, 65... Guide member, 65a... Shaft guide portion (guide groove), 81
...Positioning protrusion, 82...Body frame, 83
...Positioning hole. Applicant's Representative Patent Attorney Takehiko Suzue Figure 3 fls4 Figure 7 Figure 8 Figure 10 Figure 13

Claims (2)

[Claims] (1) In an image forming apparatus in which a developing device having a developing roller can be freely inserted into and removed from a mounting portion formed opposite to an arrangement portion of an image carrier in an image forming apparatus main body, the developing device Both ends of the shaft of the developing roller protrude from the main body of the developing device, and both ends of the shaft of the developing roller are directly guided by shaft guide portions of a guide member disposed in the mounting portion, and the guide member An image forming apparatus characterized in that: is directly attached to a main body frame to which the image carrier is attached. (2) The image forming apparatus according to claim 1, wherein the guide member has a positioning protrusion that fits into a positioning hole formed in the main body frame.