JPS63146074A - Image forming device - Google Patents

Abstract

PURPOSE:To prevent the inside of the titled device from staining and image quality from deteriorating by scattering from the lower part of a developing device of a toner, by providing a receiving member of a scattering developer or toner. CONSTITUTION:A receiving member C of a scattering developer to toner generated in a space part immediately behind a developing part is provided on the lower part of an opposed developing part of a developer carrying member of a developing device side and a latent image holding body. Accordingly, even if scattering from the lower part of the developing device of the developer or toner is generated in the space part 4 immediately behind the developing part, its scattering developer or toner is received by the receiving member C provided on the lower part of the developing part, therefore, staining (staining in the device) of an image forming process, and deterioration in formed image quality due to the face that the scattering developer or toner is diffused widely into an image forming device are obviated effectively.

Description

Detailed Description of the Invention A. Purpose of the Invention [Industrial Field of Application] The present invention applies to latent image carriers such as photoreceptors and dielectric materials, such as electronic copying machines and electrostatic recording bags, using known and appropriate processes. The present invention relates to an image forming apparatus of a type in which a PPI image is formed using a dry developing device, and the latent image is developed with toner using a dry developing device.

[Conventional technology]

Specifically, various structures and types of dry developing devices are known. In general, a well-stirred developer (l-component developer or two-component developer) is supplied to a developer chamber with a built-in developer stirring member, and the developer is carried thereon. It has a developer carrying member that conveys the developer to the surface of the PPJ image carrier to develop the latent image, and carries the remaining developer that has passed through the developing section as it is and conveys it to the developer chamber side. There are many developing devices.

[Problem that the invention seeks to solve]

In the case of such a developing device, toner scattering is likely to occur at a portion where the residual developer carried by the developer carrying member and transported back from the developing section side to the developer chamber enters the developer chamber (toner development Scattered from the bottom of the device). This is due to the following reasons.

a. The wind pressure of the turbulent air generated by the surface movement drive of the latent image carrier and the developer carrier in the space formed by the latent image carrier and the developer carrier immediately after the developing section causes the developer to be carried on the developer carrier member. A part of the remaining developer or a part of the toner contained therein passes through the developing section and is transported back to the developer chamber side of the developing device, and further migrates to the surface of the latent image holder and makes the latent image visible. Some of the toner contained in the toner may easily come off.

b. At the entrance portion where the remaining developer carried by the developer carrying member and transported back from the developing section side to the developer chamber side enters the developer chamber, a mold member on the developing device side constituting the entrance portion, etc. The remaining developer on the developer carrying member side may easily cause toner scattering due to physical contact with the developer, or the toner may accumulate on the mold member etc. over time and the deposit may occur. The clumps tend to fall off.

C1 It is easy to see the development in which part of the developer in the developer chamber of the developing device blows out backwards from the above-mentioned population area.

d. In particular, when the developer is a non-magnetic toner or contains a non-magnetic toner, the toner cannot be restrained by magnetic force, so the above-mentioned toner scattering is noticeable. Toner scattering is also likely to occur due to vibrations and shocks applied during transportation of the device. When the image forming apparatus is of a type in which a process cartridge containing at least a latent image holder is attached and detached, or in a type of a type in which a developing device is moved to change its position with respect to the latent image holder during development and non-development. In this case, toner is likely to be scattered at the lower part of the developing device due to vibrations and shocks that occur when the process cartridge is attached or removed or when the developing device is changed in position.

Scattered toner diffuses into the image forming apparatus and is one of the major causes of contaminating the image forming process equipment and reducing the functionality of the equipment, and also randomly adheres to the developing surface of the latent image holder, causing background stains on the image. Causes fogging, etc.

Therefore, in the past, various toner scattering prevention seal structures,
Although suction removal devices and the like have been devised, they have not been effective enough or have been large and complicated.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems such as staining of the inside of the apparatus due to toner scattering with a simple structure and in a sufficiently effective manner.

SUMMARY OF THE INVENTION [Means for Solving Problems] The present invention provides an image forming apparatus in which a latent image formed on a latent image holding member is developed by a dry developing device. The object of the present invention is to provide an image forming apparatus, which is characterized in that a receiving member is provided below a developing section facing an image carrier for receiving developer or toner that is generated in a space immediately after the developing section.

[For production]

Even if developer or toner is scattered at the lower part of the developing device in the space immediately after the developing section due to reasons a to d mentioned above, the scattered developer or toner will be transferred to the receiving member disposed below the developing section. Since the scattered developer or toner spreads widely within the image forming apparatus, problems such as staining of the image forming process equipment (fouling inside the apparatus) and deterioration of the quality of formed images are actually simplified. This can be effectively resolved with a suitable configuration.

〔Example〕

The drawings show one embodiment of the device of the present invention.

In FIG. 1, A is an electrophotographic photoreceptor, an electrostatic recording dielectric material, etc. in the form of a tram, Φ belt, sheet, etc. as a latent image holding body, and is driven to move in plane at a predetermined speed in the direction of the arrow. A latent image is formed by the illustrated imaging process equipment, and developed by developing device B as a visible image.

According to the present invention, C is the scattered developer generated in the space immediately behind the developing section a below the opposing developing section a between the latent image holding member A and the developing sleeve 71 which is a developer carrier described later on the side of the developing device B. This is a toner receiving member. The member C in this example is a gutter-like member with a simple cross-sectional shape, has a length approximately corresponding to the width of the developing device B, includes at least the latent image holding member A, and is attached to the main body of the image forming apparatus. The latent image holding member A is disposed substantially parallel to a process cartridge (not shown) that is attached to and removed from the latent image holding member A, or a chassis (not shown) of the main body of the image forming apparatus. Further, the member C is electrically insulated (insulated from ground) so as not to form an electric field with the latent image holder A.

In the developing device B, l is a developing container.

The interior is partitioned by a partition wall 2 into a storage chamber (toner hopper chamber) 3 for replenishing non-magnetic toner and a developer chamber (developer stirring chamber) 4 containing a developer made of non-magnetic toner and magnetic particles. The toner stored in the toner storage chamber 3 and the developer in the developer chamber 4 are omitted from the diagram for convenience.

7 is a non-magnetic developing sleeve as a developer carrying member disposed in the developer chamber 4, and the left oblique lower surface portion of the developing sleeve 71 is exposed to the outside through an opening provided in the developer chamber 4. There, 1! J, the image device B is positioned and held by the support member so that the exposed surface of the L distribution portion of the developing sleeve 71 is opposed to the surface of the latent image holder A with a predetermined small diameter gap therebetween. . - The opposing portion a between the latent image holder A and the developing sleeve 71 is a developing section.

Reference numeral 72 denotes a multi-pole magnet roll inserted into the developing sleeve 7 and serving as a magnetic field generating means. The roll of this example is a permanent magnet roll having six magnetic poles, N1 to N4 and S1 to S3, alternately magnetized at predetermined position intervals on the circumferential surface.

This magnet roll 72 is fixedly supported at both ends and does not rotate, and the outer developing sleeve 7I is rotationally driven around the fixed roll 72 in the direction of the arrow at a predetermined circumferential speed.

Reference numerals 8 and 9 designate screw shafts serving as developer stirring/transporting means that are disposed above and below substantially parallel to the developing sleeve 7 in the developer chamber 4, and are each driven to rotate in the direction of the arrow.

10 is a developer circulation regulating member provided above the developing sleeve 71 in the developer chamber 4, and 11 is the upper surface of the developing sleeve 7I in order to regulate the layer thickness of the developer formed on the circumferential surface of the developing sleeve 7. Non-magnetic blades 12 and 13 are arranged with their lower sides facing the upper surface of the developing sleeve with a predetermined small diameter gap, and 12 and 13 are attached to the lower side of the developer chamber 4 and the screw shafts 8 and 9. Developer circulation area designating members 14 and 15 for the circumferential surface of the developing sleeve 71 are respectively arranged between the bottom surface of the developer chamber 4 and the tip side of the downwardly extending portion of the developing sleeve on the bottom surface. The developer in the developer chamber 4 passes between the bottom surface of the developer chamber and the lower surface of the developing sleeve 7 and flows backward toward the latent image holder A, or It serves to prevent water from blowing out and leaking outside the device.

16 is a sensor that detects the concentration of the developer (mixing ratio of toner and magnetic particles) in the developer chamber 4, and the output of this sensor is input to a control circuit (not shown), and the toner storage is controlled accordingly. The rotational drive of the toner conveying members 61 and 62 in the section 3 is controlled.

The multi-pole magnet roll 72 as a magnetic field generating means
For each magnetic pole, the NI pole is developer coated 1+i pole,
It is located at a position substantially opposite to the non-magnetic blade 11 serving as a developer layer thickness regulating member.

The N2 pole is a developing pole and is located at a position facing the developing section a, that is, the surface A of the latent image carrier. The S1 pole serves as a developer transport pole and is located in an open position between the N pole and the N2 pole. The S2 pole and the N3 pole serve as developer leakage prevention fences, and are located at positions facing the aforementioned members 15-14 provided on the bottom surface of the developer chamber 4, respectively. The S1 pole is located at an open position between the N1 pole and the N3 pole as a developer transport ring pole.

When the developing device is in operation, the developing sleeve 71 and screw shafts 8 and 9
are each driven to rotate at a predetermined speed.

An alternating voltage is applied between the developing sleeve 71 and the Wi-shaped holder A by a bias power supply S.

By the rotation of the screw shafts 8 and 9, the developer in the developer chamber 4 is sufficiently stirred in the longitudinal direction of the developing sleeve 71, and a substantially uniform mixing ratio of toner and magnetic particles is obtained near the developing sleeve 71. Unevenness in each portion of the developing sleeve 71 in the longitudinal direction is removed.

The screw shafts 8 and 9 rotate in the directions of the arrows, so that the developer in the developer chamber 4 is separated from the developer near the screw shaft 8 on the E side and the developer near the lower screw shaft 9, respectively. The screw blades 118 and 9 of the lower screw are also arranged in opposite directions so that the screws 118 and 9 are conveyed in the opposite direction to the longitudinal direction of the screw shaft.

The movement of the developer in the developer chamber 4 on the cross section of the developer chamber is caused by the rotation of the developing sleeve 71, the rotation of the screw shafts 8 and 9, the magnetic field of the magnet roll 72, the developer circulation regulating member 10, and the circulation area. Due to the presence of designated members 12 and 13, the frictional force between the developing sleeve 7□ and the developer, the gravity of the developer, etc.
This results in a cyclical flow motion as shown by the white arrows in Figure 1. Sufficient tripo is imparted to the toner by the annular flow motion of the developer, stirring by the flow along the screw shafts 8 and 9, and the like.

Thus, the developer in the vicinity of the surface area of the developing sleeve 7 facing into the developer reservoir of the developer chamber 4, that is, the developer consisting of magnetic particles and non-magnetic toner, is transferred to the magnetic roll 72 in the sleeve 71. The developer is adhered and held as a magnetic brush adsorption layer by the magnetic force of the developing sleeve 7, and is transported toward the developer circulation regulating member 10, which does not interfere with the rotation of the developing sleeve 7. By passing the lower surface of the member 10, the developer magnetic brush is The developer is restrained, then reaches the position of the non-magnetic blade 11, and the process of passing through the position of the non-magnetic blade ÷ layer thickness is regulated, and the developer becomes a thin layer consisting of a small amount of magnetic particles and non-magnetic toner and leaves the developing area a. pass.

During the process of passing through the developing section a, the developing sleeve 7,
The latent image is formed by the brush-shaped magnetic particles contained in the developer layer on the side being formed longer than the facing gap length between the surface A of the latent image carrier and the developing sleeve 71, or by being elongated by the electric field of the developing section &. By rubbing the holding body A side and reciprocating the toner portion between the sleeve 7 side and the latent image holding body A side, the toner corresponds to the latent image pattern on the H3 image holding body A side. The toner development of the latent image on the surface of the latent image carrier is sequentially performed with transition reliability.

The developer layer on the side of the developing sleeve 71 that has been subjected to development and has passed through the developing section a is held as it is on the surface of the sleeve 71 within the developer chamber 4 by the magnetic field of the magnetic poles S2 and N3 due to the subsequent rotation of the developing sleeve 7I. The developer is transported back and mixed with the developer in the developer chamber 4 again.

As the toner in the developer in the developer chamber 4 is consumed in developing the latent image, the mixing ratio with the magnetic particles decreases over time. The degree of decrease is detected by the sensor 16, and the detected information is input to a control circuit (not shown). When the degree of decrease reaches a predetermined allowable lower limit, the signal causes the toner conveying members 61 and 62 in the toner storage section 3 to rotate. As a result, the toner in the toner storage section 3 is sequentially introduced into the developer chamber 4 through the toner replenishment port 17 and replenished.

As the sensor 16, for example, a developer volume change detection element,
A piezoelectric element, an inductance change detection element, an antenna system using an alternating bias, etc. can be used.

The replenished toner is taken into the developer in the developer chamber 4 and is mixed uniformly and quickly throughout the developer. This toner supply increases the toner mixing ratio of the developer in the developer chamber 4. When the sensor 16 detects that the toner transport members 6□ and 62 have risen to a predetermined allowable rise, the rotational drive of the toner conveying members 6□ and 62 is stopped. As a result, the mixing ratio of the toner to the magnetic particles of the developer in the developer chamber 4 is always kept substantially constant.

That is, the toner supplied into the developer chamber 4 from the toner supply port 17 is stirred and conveyed into the existing developer by the lower screw shaft 9 while moving in the axial direction, and is mixed and dispersed.

The developer then moves over the developing sleeve 7, and its circulation is regulated between the member 13 and the magnetic pole S3, and the latent image carrier A
The developer on the sleeve 7I that has been developed and put together and transported back into the developer chamber 4 and the developer transported by the screw Ikh9 are mixed and stirred, and a part of the developer is mixed and stirred by the screw shaft 8.
A part of the developer flows toward the non-magnetic blade 11 side through the lower surface of the upper developer circulation regulating member 10, receives layer thickness regulation, is held on the developing sleeve 7□, and is conveyed to the developing section a.
Provided for developing the latent image. The developer transported in the direction of the screw shaft 8 is transported in the axial direction of the screw shaft 8 in the opposite direction to the screw shaft 9, with some of the developer being transported toward the sleeve and some of it toward the screw shaft 9. Ru. When the sleeve 7 is moved in the axial direction by the screw shaft 8, the developer on the surface of the sleeve 7 is made almost uniform in the axial direction.

The member 13 regulates the ma transport of the developer near the magnetic pole S3 on the side of the sleeve 7, and also controls the ma of conveyance of the developer near the magnetic pole S3.
It plays the role of a guide plate for the developer, and also contributes to stabilizing the agitation and conveyance of the developer. In addition, there is a gap between the sleeve 71 and the developer chamber wall on the opposite side, which also serves to guide a portion of the developer circulated by the screw shaft 8 toward the screw shaft 9.

Fig. 2 shows a case in which the position of developing device B is changed with respect to latent image holder A during development and during non-development. The state in which the developing sleeve 71 is moved and held and is in a non-active, separated position from the latent image holding member A is shown.

FIG. 4 shows that during development, the plane of the latent image holder A and the developing sleeve 7 is driven to move in the wedge space formed by the latent image holder A immediately after the developing section a and the developing sleeve 71 which is a developer carrier. This shows the turbulence d that occurs accordingly. Due to the wind pressure of this turbulence, a portion of the remaining developer or a portion of the toner contained therein is carried by the developing sleeve 71, passes through the developing section a, and is transported back to the developer chamber 4 side of the developing device B. However, the fact that a part of the toner that has migrated to the side A of the latent image holding member and visualized the Wt image is detached is a contributing factor to the so-called scattering of the toner at the bottom of the developing device. As stated in section. Further, due to the above-mentioned b-d%, toner scatters at the lower part of the developing device.

However, according to the present invention, by arranging the receiving member C for the scattered developer or toner at the lower position of the developing section a as described above, the scattered developer or toner that occurs due to the reasons described in items a to d above can be removed. Most of the toner is received and captured inside the member C, and the scattered developer or toner widely spreads within the image forming apparatus, resulting in problems such as staining of image forming process equipment and deterioration of the quality of formed images. This problem can be effectively solved with a practically simple configuration.

The receiving member C in the example of FIG. 1 is electrically insulated so as not to form an electric field with the latent image carrier A.
The side edge portion (first edge portion) C1 is positioned to protrude into the wedge space formed by the latent image holder A and the developing sleeve 71 immediately after the developing portion a. The distance between the first edge portion C1 and the latent image holding body A and the distance #2 between the first edge portion C1 and the developing sleeve 7 are approximately the same, and each extends in the longitudinal direction of the axis. It is installed so that the distance between the latent image holding member A and the developing sleeve is the same. In the above sentence, the gap in 22 should be as small as possible, and 1 to 22 should be as small as possible.
It should be about 51, preferably about 1.5. This configuration not only allows the scattered developer or toner generated in the wedge space to be received inside the receiving member C, but also suppresses as much as possible the flow of turbulent air d (Fig. 4) that occurs in the wedge space. effective. FIG. 3 shows the first part C of the receiving member C.

In order to bring it as close as possible to the surface of the latent image holder A, the ji portion is bent in the direction of the latent image holder A.

An edge portion (f) opposite to the first edge portion C1 of the receiving member C
B2 edge portion) It is preferable that the distance between C2 and the bottom surface of the developing device B be as small as possible. This prevents the turbulent air Bd generated in the wedge space from rising]F and toner 7! Scatter is prevented by 1 hit or suppressed. When developing device B is developing (first
Figure 3) and non-appearance! ``&'' (Figure 2), the second edge C2 of the receiving member C is provided with an elastic cushion such as maltbrane so as not to obstruct the movement of the developing device B. It is also good to suppress the flow of wind by pasting the material 20.

The receiving member C is carried by the developing sleeve 71 from the developing section a and transported back to the developer chamber side of the developing device, and sufficiently covers the lower part of the entrance section 21 where the remaining developer enters the developer chamber side. As a result, even if the accumulated mass of toner that has accumulated over time on the bottom end portion 22 of the developer chamber constituting the entrance portion 21 falls off, it is received in the receiving member C. In addition, the member is sufficient to receive the developer and toner that fall off due to vibrations and G'I strikes when the developing device B changes its position between developing and non-developing, when the process cartridge is installed and removed, and when the image forming apparatus is transported. Accepted inside C.

By disposing the receiving member C in a process cartridge that can be attached to and removed from the image forming apparatus main body or on the image forming apparatus main body side, even when the developing section aB moves, the impact on the receiving member C is small and the material is collected inside the member C. The toner that is being used will not scatter.

The structure is simple by just disposing a simple gutter-shaped receiving member, and the dimensional accuracy with respect to the latent image holding member A can be achieved, making manufacturing easy. Maintenance can be facilitated by changing the receiving member C.

Not only one receiving member C may be provided, but a plurality of receiving members C may be arranged in multiple stages.

C1. Effects of the Invention As described above, according to the present invention, it is possible to obtain an image forming apparatus with a simple structure that eliminates the problems of staining the inside of the apparatus and deterioration of image quality due to toner scattering at the lower part of the developing device. ,
The intended purpose can be achieved well.

[Brief explanation of the drawing]

The drawings show an embodiment of the apparatus of the present invention, and FIG. 1 is a cross-sectional view of the main part, FIG. FIG. 3 is a sectional view showing another example of a receiving member for scattering developer or toner, and FIG. 4 is a partial view showing turbulent air flow generated immediately after the developing section. A is a latent image holding member, B is a developing device, 7 is a developing sleeve as a developer carrying member, and C is a receiving member for the scattered developer or toner.

Claims (4)

[Claims] (1) In an image forming apparatus in which a latent image formed on a latent image holder is developed by a dry developing device, a portion immediately below the developing portion facing the developer carrying member and the latent image holder on the developing device side is placed. An image forming apparatus comprising a member for receiving scattered developer or toner generated in a space. (2) Image forming according to claim 1, wherein the scattering developer or toner receiving member is a process cartridge that is attached to and removed from the image forming apparatus main body, or is disposed on the image forming apparatus main body. Device. (3) The image forming apparatus according to claim 1, wherein the scattering developer or toner receiving member is electrically insulated from earth. (4) The scattering developer or toner receiving member is at least an entrance through which residual developer carried by the developer carrying member from the developing section and transported back to the developer chamber side of the developing device enters the developer chamber. The image forming apparatus according to claim 1, wherein the image forming apparatus is located so as to cover the lower part of the image forming apparatus.