JPS58199364A - 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 The present invention relates to a developing device, and more particularly to a developing device Kll having a function of separating and removing different color toner mixed into a developer.
do.

After the surface of the leading electric photosensitive recording medium is charged to
il exposure is performed to discharge the charge in the area where the Rust 1 toner is to be attached to form an sl electrostatic latent image, and this sl electrostatic latent image is reversely developed using a 1sl developing device. A toner image is formed, and then a $
#I2 exposure is performed to form a second electrostatic latent image, and this #I2 electrostatic latent image is reversely developed by a second developing device to form a second electrostatic latent image.
A two-color electrophotographic recording device that forms toner images has been proposed.

When the photoconductive photosensitive recording medium is the final recording medium, the two toner images are fused as is, and when the photoconductive photosensitive recording medium is an intermediate recording medium such as a photosensitive drum that is used repeatedly. The two toner images on the recording medium are transferred to recording paper such as paper and then electrodeposited.

In such a recording device, the second electrostatic latent image is developed by the developing device at tIs2 on the surface of the recording medium where the first toner image is held by electrostatic force.
When the second developer of the second developing device is applied to the surface of the recording medium, a portion of the toner of the first toner image is scraped off from the surface of the recording medium and mixed into the developer of step 2). As the operating time of the recording device increases, this mixed toner accumulates in the second developing device, so the amount of the first toner contained in the second developer increases and the second toner image is formed. Colors are mixed and a clear two-color toner image cannot be obtained. In order to prevent color mixing of the second toner image, a developing device W- has been proposed which includes a mixed toner removing means for removing the first toner mixed into the #I2 developer. This mixed toner removal means is
Taking advantage of the difference in charging properties between the first toner in the second developer and the W42 toner, a voltage of the same polarity as the #12 toner (different polarity from the stored toner) was applied. An electrostatic adsorption roller is used to remove the first toner mixed in the second developer by electrostatic adsorption to the electrostatic adsorption roller. However, the developer flows through the developing device in a laminar flow7:
Since it is moving at C, the first layer mixed inside the layer
Therefore, the effect of removing mixed toner was not sufficient.

Therefore, an object of the present invention is to
An object of the present invention is to provide a developing device equipped with a mixed toner removing means capable of efficiently removing toner.

In order to achieve this object, the present invention provides a disturbance member that disturbs the second developer flowing down after developing the second electrostatic latent image formed on the recording medium and separates the toner. It is characterized in that it is installed at the position where the electrostatic adsorption force acts on the stomach roller or upstream thereof, and strengthens the electrostatic adsorption force of the electrostatic adsorption roller that acts on the mixed toner @1, thereby increasing the efficiency of removing the mixed toner. shall be.

@1 formed on the recording medium. If both of the electrostatic latent images in storage 2 are negative latent images (charges are released from the area to which toner is to be attached), 111 in the developing device of w41.
The triboelectric charging characteristics of toner No. 1 and toner No. 12 in the IJ42 developing device with 'F Yaria or other tribocharging members are selected so that the toner No. 1 and toner No. 12 in the IJ42 developing device have reversal development characteristics when charged with the same polarity. Therefore, in this case, when the lth toner is mixed into the site agent @2, the charging polarity is reversed due to frictional charging between the developer l1s2 and the second toner, carrier, or other triboelectric charging member. It is necessary to select the material so that it has good umbrella charging characteristics.

Also, the electrostatic latent image on the hook 1 is a negative latent image, the developer on the wheel 1 has reversal development characteristics, and the second electrostatic latent image is a positive latent image (charges from areas where toner is not desired to adhere are released). So #12 developer is the official one! In the case of the J characteristic, the first toner in the 11!11 developing device and the second toner in the second developing device are in a unipolar charged state. Therefore, since the first toner mixed in the second developer is initially monopolar with respect to the second toner, it is necessary to select a material that has triboelectric charging characteristics that can maintain its charging polarity. .

Hereinafter, the present invention will be explained in detail based on illustrated embodiments.

FIG. 1 is a schematic diagram of a two-color electrophotographic recording system to which the present invention is applied. In the figure, a photoconductive photosensitive drum 1 is driven at a constant rotational speed in the direction of arrow U), and its surface is first uniformly charged, for example to a positive polarity, by corona charging II2. Uniformly, the surface of the charged photoconductive photosensitive drum 1 is exposed to the l-th primary light beam 3 to form a negative electrostatic latent image of wjl, and this electrostatic latent image of wil is the electrostatic latent image of #11. #1. The image is developed by the first developer 5 in the developer 4. This W41 developing device 4 has a reversal developing function, and the developer 5 is positively charged 11
11 toner 5a (exaggeratedly shown) and a magnetic carrier (not shown) are attracted to the surface of a developing roller consisting of a magnetic roller 48 and a non-magnetic sleeve 4b and emit light 4.
A magnetic brush is formed that lightly rubs the surface of the electrophotosensitive drum 1. As a result of this development, a toner image (5a) of silk 1, which is electrostatically adsorbed with Wt on the 1st electrostatic latent image, is formed on the surface of the photoconductive photosensitive drum 10. After that, the photoconductive photosensitive drum l
The unlit area of the silk 2 is unified by the second ray 6 to form a negative second electrostatic latent image, and this electrostatic latent image of the silk 2 is formed by the ts2 in the second developing device 7. It is developed with developer 8. The developing device 7 of this toner 2 has a reversal development function, and the developer 8 is a positively charged second toner 8α (
A magnetic carrier (not shown) is attracted to the surface of a developing roller consisting of a magnetic roller 7α and a non-magnetic sleeve 7b, and lightly rubs the surface of the photoconductive photosensitive drum 10. It forms a brush. This second developing device 17 uses the developing device according to the present invention, and the details will be described later.Due to this development, the electrostatic latent image r of the ship 2 is absorbed onto the surface of the photoconductive photosensitive drum 10. 2
A toner image (8α) is formed. In this way, the sales floor was made up of sugar 1. The toner image of the porcelain 2, . And transfer the photo to the photosensitive drum IO) surface with cleaner 11, #r,? After completing the four-child photo process, we begin the next step, the Arashito photo session. In this device, a two-color toner image can be obtained on the bud 9 by making the toner 5α of the vessel 1 and the 42nd toner 8α different colors.

m 2 W bar period L 1 1, 12th F) Toner 5α, f3 of developer 5.8 used in developing device M 4 , 7
In the distribution diagram of #toner charge of each particle in a, the first toner 5α
is curve 1. The second toner Ha is distributed as shown by curve I due to non-uniform toner particle diameter. However, the second toner 8
The flat MW electric charge jIli of G is about 5 to 20 s c/f larger than that of the first toner 5a. and,#! l toner 5th is the second present 1.4! Mark; 8
When it gets mixed in, the charging device becomes like song II,
Therefore, the #1 toner 5a in the #I2 developer 8 is electrostatically attracted to the electrostatic attraction roller to which a positive potential of 1 is applied, and can be removed.

Next, an example of the present veneer [17] of copper 2 to which the present invention is applied will be described in detail with reference to FIG. Second modern version-7
At the bottom of the valley < arc is the 2nd J) toner 8G and carrier °
r? ! A mixed developer 81J1 of i and +12 is contained, and this second developer 8 is stirred by a stirring blade $7, so that the toner 8α of the sheet 12 is positively charged.

Magnetic IJ-rough d and non-magnetic sleeve 7c are tTh2,
The rollers are now 14-(), and the non-magnetic sleeve 7e of the transport roller and the non-magnetic sleeve 7b of the current roller are indicated by the arrow (
c).

), the second developer 8 at the bottom of the container 2i+7C is layered on the surfaces of the double-valve magnetic sleeves 7b and 7e in the direction of the arrow! /→6) is transported in the b direction. The regulating member 7f is arranged to control the magnetic field 8 formed on the surface of the non-magnetic sleeve 7b.
By setting the height to a predetermined value, the magnetic brush acts on the surface of the photoconductive photosensitive drum l to a degree of 1M. This second development forms a layer of #I2 toner 1 (8α) on the surface of the photoconductive drum 1, but the tal that was previously formed on the surface of the photoconductive drum 1 is removed. Toner 1 elephant (5
A part of the toner α) is scraped off and mixed into the magnetic brush (first developer 8) of the second developing device 7. After the development, the magnetic brush on the surface of the non-magnetic sleeve 7b is scraped off by the scraping member 'ItK, and the developer flows down as 80 layers, and is processed by the mixed toner removing means 12.
Return to the bottom of lK*l17c. Mixed toner removal means 12
a stirring impeller 12g that stirs the developer 8 that has flowed down along the scraping member 7t while rotating in the direction of the arrow;
I! stirred by the stirring impeller 12a! Developer 8 flowing down to
The disturbance member 12C collides with the developer 8 that has been disturbed and separated.
The electrostatic loosening roller 12- and the ground electrode plate □12s apply electrostatic adsorption force to the surface of the electrostatic adsorption roller 12d. Electroadsorbed If toner 5a
and a scraping member 12f for scraping off the first toner 5α that has flown up from the second developer 8 or the first toner 5g that has been scraped off from the electrostatic adsorption roller 12d. An air suction passage 12b is opened to these areas.
It is equipped with The electrostatic adsorption roller 12d is a conductive substrate whose surface is insulated and rotated in the direction of the arrow.

In the above #I configuration, as described above, the second developer 8 and the stored toner 5G mixed therein are transported along the surface of the non-magnetic sleeve 77b or along the scraping member 7fK. The liquid is agitated in the process of flowing down, or by an agitation impeller 128. As a result, from the charging characteristics mentioned above, #! The amount of charge of the toner 5a of No. 1 decreases to near zero, or the polarity of charge is reversed. #11 toner 5cL, whose charge amount is close to zero, has a weak electrostatic bonding force with the second developer 8, so such first toner 5G is separated from the developer 8 with tI/42. Passage 1 by the suction air flow
2bK@ is withdrawn. In addition, the electrostatic polarity was reversed and the #! The toner 5G of ml is combined with the second developer 8 by electrostatic force, flows down, collides with the disturbance member 12C, and is separated into ゛f# turtle adsorption award - la 12dK-, which has the opposite polarity to the toner 5α of ml. Turtle @ is worn.

At this time as well, the #11 toner 5a with a small amount of impurity is blown up, carried by the suction air flow, and sucked into am'tzb.

Further, when the @2 toner 8G forming vI4 of the second developer 8 is repeatedly used, the charging characteristics of a part of it deteriorate, the amount of charging decreases, and the developing characteristics deteriorate.

However, some of the second toner 8G that has deteriorated in this way also has a reduced charge amount, so that the #! 1 to, na 5α
As in the case of , it separates from the carrier due to conveyance, flowing down, agitation, and disturbance and floats up, so it is sucked and removed by the suction air flow.

In particular, #11 toner 5 mixed in the second developer 8
When α is adsorbed by the electrostatic adsorption force of the electrostatic adsorption roller 12d, or when some degraded #12 toner 8α is removed by suction air, these first and #42 toners 5α and 8cL are When buried in the laminar flow of #I2 developer 8, it becomes difficult for electrical or mechanical pulling force to act on these toners 511 and 8α. Toner 5a, 13g
is difficult to remove. However, according to the embodiment of the present invention described above, the static l! The adsorption force or saponification air force acts on the area where the developer 8 of one mackerel 2 collides with the disturbance member 12C on the way down and is disturbed and separated, and a part of it is in the form of smoke. It acts effectively on the toner 5a or the toner 8a of the deteriorated car 2, and can efficiently remove them. Electrostatic adsorption roller 12d
The electrostatically adsorbed toner 5G is scraped off by the scraping member 129 and then sucked into the air suction passage 12b, but a toner collection container is provided below the scraping member 12f to collect it. You can also do that.

#! 4 shows another embodiment of the present invention. 1. The characteristic difference in structure of this embodiment from the previously described embodiment is that #I2 flowing down on the surface of the scraping member 7t X number of stirring protrusions 12h, 12 for stirring the agent 8
i and 12j, and the flowing developer 8 falls from the lower end of the scraping member 7f onto the disturbance member 12, C, and is disturbed and separated. Since it is the same as the example, the same reference numerals are given and detailed explanation is omitted.

In this embodiment as well, the developer 8 of the developer 2 and the toner 5a mixed therein are as shown in Table 1 of the non-magnetic three 17b.
! In the process of being conveyed, the toner 5a of the final stage 1 is agitated while flowing down along the scraping member 71, and the amount of charge of the toner 5a in the first stage decreases to near zero or the polarity of the charge is reversed. In particular, in the process of flowing down along the scraping member 7I, the stirring protrusion 12h
Due to the presence of ~12j, $2 developer 8 and @1F) tot
Since the stirring action of −5α is promoted, it is possible to reduce the amount of charge or reverse the polarity of the ill toner 5 with a simple configuration without using a stirring impeller. Therefore, similarly to the above embodiment, the mixed #11 toner 5α and the deteriorated second toner 8a can be efficiently separated and removed.

In the above two embodiments, a two-component developer in which a toner and a carrier are mixed is used, but it is clear that the same method can be applied to an l-minute developer. Further, if the first toner 5a used in the first developing device 4 and the $12 toner 8G- used in the second developing device 7 have different charge polarities from the beginning, the second developing device 7 #11 toner 5 provided in conjunction with
It is also possible to omit stirring sm for adjusting the amount of charge in step 8.

The present invention also provides sugar 2 in an electrophotographic recording device for two or more colors.
．． Third. It goes without saying that the present invention can also be applied to each developing device.

As described above, according to the present invention, after developing the second electrostatic latent image formed on the recording medium, the disturbance member that disturbs the developer of IJ2 flowing down and separates the toner is moved to the electrostatic adsorption roller. Since the electrostatic attraction roller is provided at the position where the electrostatic attraction force acts or upstream thereof, the electrostatic attraction force of the electrostatic attraction roller that acts on the mixed first toner is strengthened, and the mixed toner removal efficiency is increased.
This has the effect of providing a developing device π that has a developing function without color mixing in the long term.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention, and FIG. 1 is a schematic diagram of a groove of a two-color electrophotographic recording device, FIG. 1/42 is a toner charge amount distribution diagram, and FIGS. FIG. 3 is a vertical side view of the developing device. 1...Photoconductive photosensitive drum, 5a...f
it's toner (pick 1 toner @), 7...2nd
Developing device, frame...Non-magnetic sleeve, foot...
...Scraping member, 8...Developer of 1112, 8α...Second toner (#12 toner), 12...Removal of mixed toner Means, 12C・
...Disturbing member, 12d... Electrostatic adsorption roller. ? 1 group 1lte 巳f3kuni

Claims (1)

[Claims] 1゜ The electrostatic latent image 1112 formed on the recording medium holding the electrostatic latent image Kwk of #ll and the toner group of ring l is developed with a second toner. The developing means of wi2 includes a developing roller that causes the developer of container 2 containing toner #12 to act on the surface of the recording medium, and a guide member that guides the flow of the developer of w42 separated from this developing roller. Then, #11 toner i, which is charged with a different polarity from the toner of Km 2 in the developer of 11!2 flowing down, is transferred to an electrostatic adsorption roller to which a voltage of the same polarity as the toner of $112 is applied. In the developing device 1 equipped with a mixed toner removing means that removes mixed toner by adsorption,
A developing device characterized in that the mixed toner removing means has a disturbance member that disturbs the flowing second developer and separates the toner, at a position where the electrostatic attraction force is applied to the electrostatic attraction roller or upstream thereof. Device. λ In claim m1, the mixed toner removing means removes the l-th toner mixed into the developer of wi2 by 8
1. A developing device characterized by comprising a stirring means for stirring with the developer of No. 2 and charging the toner with a polarity different from that of the toner of No. 2.