JPH0368973A - Developing device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a developing device applied to an image forming apparatus such as a color printer.

(Prior art) In recent years, non-magnetic
Those using component developers are being put into practical use. This type of developing device can be significantly smaller and lighter than one using a two-component developer consisting of toner and carrier. Furthermore, since no carrier is used, the photoreceptor drum and transfer drum are not damaged. Furthermore, since it is non-contact development, no jitter occurs. In addition, magnetic toner, especially when used in color printers, suffers from poor color rendering properties due to the presence of magnetic powder mixed in the toner, but it has various advantages such as not having such problems.

Usually, this type of developing device has a configuration as shown in FIG. In the figure, a is a developing roller, b is an elastic foam roller, and C is an aluminum roller.

A non-magnetic component developer (hereinafter referred to as toner) t in a container d is carried to the right in the figure by an aluminum roller C and an elastic foam roller b, is drawn up by a developing roller a, and is transferred between the developing roller a and the toner. The developing roller a is fed between the developing roller a and the blade e which is in pressure contact with the developing roller a. Here, the toner t is made into a thin layer, charged, and sent to the photosensitive drum f side.

At this time, since a bias is applied to the developing roller a, the toner t is directed toward the exposed portion of the photoreceptor drum f, which faces the developing roller a at a minute distance, that is, toward the electrostatic latent image.
flies, and the electrostatic latent image becomes visible.

The toner t remaining on the developing roller a without flying away is collected into the container d by the urethane blade g, and then scraped off by the elastic foam roller b. The toner then passes under the elastic foam roller b and the aluminum roller C and returns to the toner reservoir above the aluminum roller C.

In such a non-magnetic component developing device, what controls the developed density is the state of pressure contact of the blade e with the developing roller a, that is, firstly, the pressure contact force F of the blade e with the developing roller a; The length of the tip of the blade e, especially the length from the pressing part shown in the figure to the tip, is also important.

Particularly in the case of color toners other than black, density unevenness is noticeable, so it is necessary to ensure that thin and uniform development can be achieved throughout. In particular, in the case of a color printer, it is desirable to make the density of each color as thin and uniform as possible in order to overlap colors in multiple layers.

If the density is too high, the entire image will look raised, the color will be poor, and it will be difficult to fix, so it is necessary to be able to develop thinly and evenly over the entire area.

In a conventional developing device, a blade holder i holding a blade e is rotatably held around a spindle j, and the pressure contact force of the blade e is applied by pushing the blade holder i with a screw k to rotationally displace the blade holder i. I was adjusting F.

Further, the tip length L of the blade e was determined by the dimensions of the blade e.

However, with such a configuration, the inclination of the blade e cannot be adjusted from the outside.

For this reason, in the case of toner with poor fluidity such as magenta toner, when the toner layer is made thin, density unevenness may appear in the axial direction of the developing roller a, but this density unevenness cannot be corrected. could not.

(Problems to be Solved by the Invention) As described above, in conventional developing devices, it is not possible to adjust the inclination of layer forming members such as blades from the outside, and the development density in the longitudinal direction of the developer holder such as the developing roller. There was a problem that unevenness could not be corrected.

The present invention has been made to solve the above problems, and its purpose is to form a developer layer on the developer holder by bringing a layer forming member into pressure contact with the developer holder, and to form a developer layer on the developer holder. In a developing device that develops an electrostatic latent image formed on an image carrier, the inclination of the layer forming member can be adjusted from the outside, and uneven development density in the longitudinal direction of the developer holder can be easily and reliably corrected. It is an object of the present invention to provide a developing device that can perform correction.

[Structure of the Invention (Means for Solving the Problems) In order to solve the above problems, the present invention provides a method for forming a developer layer on a developer holder by bringing a layer forming member into pressure contact with the developer holder. , in a developing device that develops this developer layer in opposition to an electrostatic latent image formed on an image carrier, at least one end side of a holder for holding the layer forming member in parallel with the developer holder; A support position adjusting means is provided for varying the support position of the support position.

(Function) That is, according to the present invention, when uneven development density occurs in the longitudinal direction of the developer holder, at least one end of the holder for holding the layer forming member in a state parallel to the developer holder. By adjusting the support position adjusting means that changes the side support position, the inclination of the layer forming member can be adjusted from the outside, making it possible to easily and reliably correct uneven development density in the longitudinal direction of the developer holder. Become.

(Example) An example of the present invention will be described below with reference to FIGS. 1 to 6. FIG. 2 shows the configuration of a full-color laser printer employing the developing device of the present invention, and 1 in the figure is the main body of the device. At the upper center of the apparatus main body 1 is a photoreceptor drum 2 whose surface is coated with an organic photoreceptor as an image carrier.
A charging device 3, a multicolor developing device 4, a transfer drum 5, a cleaning device 6, and a static eliminating device 7 are provided around the photosensitive drum 2 along the rotation direction (arrow E direction). are arranged in sequence. Furthermore, a laser exposure device 8 for exposing image information is provided in the upper part of the main body 1 between the charging device 3 and the developing device 4. The multicolor developing device 4 includes developing unit units 4a to 4djj containing yellow, magenta, cyan, and black non-magnetic component developers (referred to as toners) t.

Further, a paper feed cassette 10 containing paper P such as plain paper is attached to one side of the apparatus main body 1, and a paper feed means 1
1, the sheets are fed one by one.

Paper P fed from the paper feed cassette 10 is conveyed along a U-turn conveyance path 12 and guided to a paper discharge tray 13 mounted above the paper feed cassette 10. The transfer drum 5, the peeling means 14, and the fixing device 15 are opposed to the U-turn conveyance path 12.

During image formation, the photoreceptor drum 2 rotates in the direction of arrow E, and the surface of the photoreceptor drum 2 is uniformly negatively charged by the charging device 3.

Thereafter, the image information is exposed by the laser exposure device 8, and the charge on the surface of the photoreceptor drum 2 is selectively removed to form an electrostatic latent image.

Next, this electrostatic latent image is transferred to the developing unit 4a (of the developing device 4) containing the preset first color toner t.
4b, 4c, and 4d), the charged non-magnetic component developer (toner) t is deposited and visualized by a non-contact jumping method.

On the other hand, at this time, the paper P fed from the paper feed cassette 10 is wound around the transfer drum 5 with its leading edge held by the gripper 5a. Then, the transfer drum 5 rotates in the direction of arrow F while a positive bias is applied, and the toner image on the photosensitive drum 2 is transferred onto the paper P at a transfer position A point.

Note that the toner t that has not been completely transferred is cleaned by the cleaning device 6, and the memory of the photosensitive drum 2 is removed by the static eliminator 7, and the next cycle begins.

Here, when transferring a plurality of colors, the transfer drum 5 is rotated once again, and during this period, the second color developer unit 4b (4c, 4d) of the developing device 4 is transferred.

4a) are sequentially switched to face the photoreceptor drum 2.

After the transfer has been performed a predetermined number of times in this manner, the peeling means 14 operates to peel the paper P from the transfer drum 5 and enters the paper ejection process. Then, the fixing device 15 fixes the paper P.
The upper toner image is heated and fixed, and the paper is discharged onto the paper discharge tray 13.

Next, the configuration of the developing unit 4a of the multicolor developing device 4 will be explained. Note that other developing unit 4b,
4c and 4d also have the same configuration as the developing unit 4a, so their explanation will be omitted.

The developing device unit 4a as a developing device of the present invention has a third
The configuration is as shown in the figure. In the figure, 20 is a casing, and inside this casing 20 are a photoreceptor drum 2 and 0.
Developing rollers 21 are provided as developer holders facing each other with a small gap G of about 25 mm between them. This developing roller 21 is made of #60 on the surface of a stainless steel sleeve.
0 sandblasted material is used.

Further, within the casing 20, an elastic foam roller 22 made of urethane sponge or foam rubber is arranged in rolling contact with the developing roller 21, and an aluminum roller 23 is further arranged in rolling contact with the elastic foam roller 22. It is in a state.

In addition, a stainless steel blade 24 with a thickness of 0.15 mm is placed diagonally above the developing roller 21 as a layer forming member.
Further, a urethane blade 25 is in pressure contact with the diagonally lower part.

Note that 26 is a lid member, and 27 and 27 (only one of which is shown) are side frames.

Moreover, the stainless steel blade 24 as a layer forming member is
The upper edge portion is held by a blade holder 28 serving as a holding body, and is arranged parallel to the developing roller 21 .

The blade holder 28 is rotatably supported around supports 30 attached to both ends in the longitudinal direction, and also has a pressure contact force screwed into a stay 31 horizontally suspended between the side frames 27 and 27. When the upper surface is pushed by the adjusting screws 32, 32, it is rotated in the direction of arrow B in FIG. Then, the pressure welding force adjustment screw 32,
The tightening of 32 is such that the pressing force of the stainless steel blade 24 against the developing roller 21 can be adjusted depending on the situation.

Further, the developing roller 21, the elastic foam roller 22, and the aluminum roller 23 are rotatably supported via bushings (not shown) attached to the side frames 27 and 27. And these rollers 21.22.2
A support shaft 21a protrudes from the entire surface of the front side frame 27 of No. 3.

As shown in FIGS. 4 and 5, gears 35, 36, and 37 are attached to 22a and 23a, and an intermediate gear 38 is rotatably attached to a shaft 40, so that they interlock with each other. The structure is as follows.

Further, positioning rollers 41, 41 are attached to the support shaft 21a of the developing roller 21, and the entire developing unit 4a is urged to rotate around the shaft 42, so that the positioning rollers 41, 41 are The body drum 2 is in rolling contact with the body drum 2, so that the predetermined gap G can be secured.

Thus, the non-magnetic component toner t that has entered the casing 20 is carried to the right in FIG. image roller 21
It is sent between the stainless steel blade 24 and the stainless steel blade 24 that comes into pressure contact with the stainless steel blade 24. Here, the toner t is made into a thin layer, charged, and sent to the photosensitive drum 2 side.

At this time, the developing roller 21 is supplied with -250V and AC voltage.
Since a bias of 1,2 KV is applied, the toner t flies toward the exposed portion of the photosensitive drum 2 facing the developing roller 21 with a minute gap G, that is, toward the electrostatic latent image.
The electrostatic latent image becomes visible.

Note that toner t remaining on the developing roller 21 without flying away
is collected into the casing 20 by the urethane blade 25 and then scraped off by the elastic foam roller 22. The toner then passes under the elastic foam roller 22 and the aluminum roller 23 and returns to the toner reservoir 43 above the aluminum roller 23 .

In addition, in the present invention, the support position adjusting means 4 described later is
5, the support position of the support shaft 30 on the front side of the blade holder 28 can be changed as shown by arrow C in FIG. If unevenness in the development density occurs in the longitudinal direction of the developing roller 2, the stainless steel blade 24
It is now possible to easily and reliably correct uneven development density by adjusting the inclination of the image from the outside.

The support position adjusting means 35 has a structure as shown in FIGS. 4 to 6. That is, the blade holder 28
The support shaft 30 attached to the front end of the flat washer 46
, the bearing hole 47a of the movable bearing 47, and the shaft insertion hole 27g of the side frame 27, and is screwed into the screw hole 28a of the blade holder 28.

The inner diameter of the shaft insertion hole 27a of the side frame 27 is formed to be considerably larger than the outer diameter of the support shaft 30, and the support shaft 30 is movable in the radial direction.

Further, the movable bearing 47 that pivotally supports the support shaft 30 has a rotation center hole 47b at a position displaced from the bearing hole 47a,
It is rotatably supported by a pin 48 screwed into the side frame 27.

Furthermore, the movable bearing 47 has a first set screw 48.
Four nut members into which are screwed are integrally molded, and the tip of the first set screw 48 is connected to the intermediate gear 38.
It comes into contact with the circumferential surface of the shaft 40 to which it is attached. By screwing in the first set screw 48, the movable bearing 47 moves in the direction of lifting the support shaft 30 around the pin 48 (in the state shown in FIG. 5, arrow U
direction).

On the other hand, a second set screw 51 is screwed into a screw hole 27b provided in a position corresponding to the shaft insertion hole 27a of the side frame 27, and its tip abuts against the circumferential surface of the support shaft 30. It is in a state. By screwing in this second set screw 51, the movable bearing 47
is the direction in which the support shaft 30 is pushed down around the pin 48 (the fifth direction)
In the state shown in the figure, it is rotatably displaced in the direction of the arrow.

Then, the first set screw 48 and the second set screw 51 are turned alternately to mount the blade holder 28.
The support position of the front side support shaft 30 can be varied in the direction of arrow C in FIG.

Thereby, when unevenness in development density occurs in the longitudinal direction of the developing roller 21, it is possible to easily and reliably correct the unevenness in development density by adjusting the inclination of the stainless steel blade 24 from the outside.

According to this invention, the pressing force F of the blade 24 against the developing roller 21, which controls the developer density, and the pressing length L of the blade 24 from the tip to the tip can be easily adjusted from the outside.

In the above embodiment, the support position of the front side support shaft 30 of the blade holder 28 is made variable, but the support position of the three rear side support shafts may also be made variable. good.

In addition, it goes without saying that the present invention is not limited to the above-mentioned embodiment, and that various modifications can be made without departing from the gist of the present invention.

[Effects of the Invention] As explained above, according to the present invention, a layer forming member is brought into pressure contact with the developer holder to form a developer layer on the developer holder, and this developer layer is applied to the image carrier. In a developing device that develops the electrostatic latent image formed on the surface of the developing device, the inclination of the layer forming member can be adjusted from the outside, making it possible to easily and reliably correct unevenness in the developing density in the longitudinal direction of the developer holder. This has the advantage that it is possible to provide a developing device that has the following characteristics.

[Brief explanation of drawings]

1 to 6 show an embodiment of the present invention,
FIG. 1 is an explanatory diagram showing the supporting state of the blade, which is the main part of the present invention, FIG. 2 is an internal configuration diagram of a full-color printer that employs the developing device of the present invention, and FIG. 3 is a schematic diagram of the developing device. , FIG. 4 is a partially cutaway front view showing the structure of the support position adjusting means, FIG. 5 is a side view, FIG. 6 is an exploded perspective view, and FIG. 7 is a diagram showing a conventional example. . 2... Image carrier (photosensitive drum) 4a to 4d...
・Developing device (developing device unit), 21... Developer holding body (developing roller), 24... Layer forming member (stainless steel blade), 28... Holding body (blade holder), 4
5...Support position adjustment means, t...Developer (toner)
. Figure 1

Claims (1)

[Claims] A layer forming member is brought into pressure contact with the developer holder to form a developer layer on the developer holder, and this developer layer is opposed to an electrostatic latent image formed on the image carrier. A developing device that performs development using a developer holder, characterized in that the developing device is provided with a support position adjusting means for changing the support position of at least one end of the holder for holding the layer forming member in parallel with the developer holder. .