JPH11194614A - Developing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent abnormal noise from being produced and trouble from being caused by forming a partition for preventing the advance of developer and a space part in the housing of a developing device so that developer in a developer storing part may not advance to a space between the rotary shaft part of a rotating member and a bearing member. SOLUTION: Two lower space parts 53A and 54A formed between three partitions (rib) 1g erected from the bottom part of a developer housing 1, and plural upper space parts 53B and 54B formed between three partitions (rib) 8g hanging down from the inner surface of a top board 8 are arranged between the end of the blade part 5C of a supply roller 5 and one bearing member 51. The plural ribs 1g having the shape of projections of the board 8 are respectively fit in the plural ribs 8g having the shape of recessions of the housing 1, and a semicircular recessed part formed on the rib 1g and the semicircular recessed part formed on the rib 8g are opposed to form a circle, then a part opposed to the rotary shaft part 5A forms the partition having the shape of a circular ring for preventing the advance of developer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a developing device provided in an image forming apparatus such as an electrophotographic copying machine, a printer, and a facsimile.

[0002]

2. Description of the Related Art As a developing method of an electrophotographic apparatus, there are known a normal developing method used for a normal electrophotographic copying machine and the like, and a reversal developing method used for a digital printer and a digital electrophotographic copying machine. The reversal development method generally uses a laser, LED, or the like as a light source and develops a latent image formed on the image carrier by charging and exposure with a toner charged to the same polarity as the charged polarity of the image carrier. It is a method to be. For example, when the charge polarity of the image carrier is negative, the polarity of the toner is also negative, and development is performed using a potential difference caused by exposure to form a toner image on the image carrier. After the development, the transfer material is charged to a polarity opposite to that of the toner by a transfer device using corona discharge or the like, and the toner image on the image carrier is transferred by the transfer material. Then, AC
After lowering the potential of the transfer material by corona discharge or DC corona discharge and reducing the adhesive force between the transfer material and the image carrier,
The transfer material is separated from the surface of the image carrier, and the process proceeds to the next process.

In a conventional developing device, a rotating developer carrier is arranged near a rotating image carrier. The developer carrier is formed in a hollow cylindrical shape, and is housed in a housing having an opening on a side facing the image carrier. The developer carrier has, for example, -650 V
Is applied with an AC voltage of 2700 V and 8000 Hz. The developer carrier has a fixed magnet inside, and carries a two-component developer in which toner particles and magnetic particles (carrier) are mixed on the outer peripheral surface of the developing sleeve.

The developing device includes a developing device housing containing a two-component developer composed of the toner and the carrier, a developer carrier having a magnetic field generating means having a fixed magnetic material therein, a developer supply roller, and the developing device. The image forming apparatus includes a developer layer thickness regulating member for regulating the thickness of the developer layer on the developer carrier to a predetermined amount, and a developer stirring and conveying member. The toner replenished from the toner cartridge into the developing device housing at the toner replenishing port opened at the upper portion of the developing device housing is provided with the developer contained in the developing device housing by the rotating developer stirring and conveying member. The toner is stirred and mixed to obtain a uniform toner concentration, and is supplied onto the outer peripheral surface of the developer carrier by the rotating developer supply roller.

[0005]

A developing device having a rotating member such as a developer stirring and conveying member for stirring and conveying a developer housed in a housing of the developing device has been conventionally known.

The rotating shaft of the rotating member is rotatably supported at both ends by a supporting portion such as a bearing. When the rotating member is constantly rotating, the developer gradually enters the supporting portion. Will come.

As a result, the rotating member does not rotate smoothly,
There is a possibility that an abnormal sound is generated or the rotational torque of the developer stirring / conveying member increases, causing a problem in the drive unit of the developing device.

[0008]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a developer stirring / conveying member or the like housed in a housing of a developing device. An object of the present invention is to provide a developing device that prevents a developer in a developer accommodating portion from entering a support portion such as a bearing that rotatably supports a shaft end of a rotating shaft of a rotating member.

A developing device according to the present invention includes a developer accommodating portion formed in a housing of the developing device, a developer carrying device for carrying the developer, a rotating member rotating in the developer accommodating portion, and a rotating member. A bearing member rotatably supporting a rotating shaft portion of the member, wherein the developing device is configured to prevent the developer in the developer accommodating portion from entering between the rotating shaft portion of the rotating member and the bearing member. Wherein a partition wall and a space for preventing the developer from entering are formed in the housing.

[0010]

FIG. 1 is a vertical sectional view of a developing device of the present invention, and FIG. 2 is a horizontal sectional view of the developing device.

In these figures, reference numeral 1 denotes a developing device housing (housing) for accommodating a two-component developer composed of a toner and a carrier, and 2 denotes a developer arranged opposite to an image carrier (hereinafter referred to as a photosensitive member). A carrier (hereinafter, referred to as a developing sleeve) 3 is a magnetic field generating means (magnet roll) having a magnetic material fixed inside the developing sleeve 2, and 4 regulates a thickness of the developer layer on the developing sleeve 2 to a predetermined amount. A developer layer thickness regulating member 5 for supplying developer to the developing sleeve 2; a paddle-shaped developer supply member (rotating member, hereinafter referred to as a supply roller); and 6 and 7 a screw-shaped developer stirring and conveying member. (Rotating member, hereinafter referred to as a transport screw). E1 is an AC power supply and E2 is a DC power supply. The arrows shown in the drawings indicate the rotation direction of each roller.

The transport screw 6 and the transport screw 7 are connected to the partition wall 1 standing upright from the bottom of the developing device housing 1.
The first transfer chamber (developer accommodating section) 1b and the second transfer chamber (developer accommodating section) 1c formed on both sides of the line a are arranged in parallel, and are driven and rotated in opposite directions. . The upper part of the developing device housing 1 is closed by a top plate (lid member). Reference numeral 10 denotes an image carrier (photoconductor) that forms an image on the surface.

The toner replenished from a toner cartridge (not shown) via a toner storage unit and a toner conveying unit is
The toner is supplied and supplied into the first transfer chamber 1b from the toner supply port 8a formed in the top plate 8.

In the developing sleeve 2, a plurality of magnetic poles N
A magnet roll 3 in which 1, N2, N3, S1 and S2 are alternately arranged is fixed. Of these plural magnetic poles, any two adjacent poles N2 and N3 adjacent to each other are arranged to have the same polarity, and the adjacent magnetic poles (peeling magnetic poles) N2 and N3 having the same polarity form a repulsive magnetic field. A stripping magnetic pole portion for stripping the later developer from the developing sleeve 2 is formed.

The outer diameter of the developing sleeve 2 is φ8 mm or more,
φ60 mm or less is desirable. When the outer diameter is φ8 mm or less, the magnetic poles N1, S1, S2 necessary for image formation, the magnetic pole N3 facing the developer layer thickness regulating member 4, and the stripping magnetic pole N
It is not possible to form a magnet roll 3 having at least five magnetic poles of 2, N3.

When the outer diameter of the developing sleeve 2 is 60 mm or more, the size of the developing device is increased. In particular, in a color image forming apparatus having a plurality of developing devices (for example, Y, M, C, and K developing devices), the outer diameter of the photoconductor 10 increases as the size of the developing device increases. In addition, it becomes difficult to perform curvature separation after transfer to a transfer material and charge removal. Further, the size of the image forming apparatus is increased due to the enlargement of the developing device and the photoconductor 10.

In FIG. 2, the vicinity of both shaft ends of the developing sleeve 2 is rotatably supported by ball bearings 21 and 22. Both ends of the magnetic field generating means 3 having a plurality of magnetic poles are fixedly supported. A gear G1 coaxial with the coupling K connected to a drive source (not shown) drives and rotates a gear G2 fixed to one shaft end of the developing sleeve 2. The gear G3 fixed to the other shaft end of the developing sleeve 2 drives and rotates a gear G4 fixed to one shaft end of the supply roller 5 via an intermediate gear (not shown). The gear G4 transmits the drive to a gear G5 fixed to the rotation shaft of the transport screw 6 via an intermediate gear (not shown). The gear G5 transmits drive to a gear G6 fixed to the rotation shaft of the transport screw 7. In this way, the driving rotation of the gear G1 causes the developing sleeve 2, the supply roller 5, and the conveying screws 6, 7 to be simultaneously rotated in the directions of the arrows shown in FIG. In addition,
The surface of the developing sleeve 2 is rotated in a direction opposite to the photosensitive drum 10 at a position facing the photosensitive drum 10.

The toner supplied from the toner cartridge to the toner supply port 8a of the developing device via the toner hopper and the toner conveying means is conveyed in the direction indicated by a double arrow in FIG. Through the opening 1d of the second transfer chamber 1c. The toner sent into the second transport chamber 1c is transported by the transport screw 6 in the double arrow direction shown in the drawing,
Stirring and mixing with the developer contained in the second transfer chamber 1c;
It is conveyed and supplied to the supply roller 5.

A toner density detecting device 9 is fixed to the bottom of the developing device housing 1 of the developing device. The toner concentration detecting device 9 is connected to the second transfer chamber 1 of the developing device housing 1.
c or the first transfer chamber 1 b, and based on the detection result of the toner concentration detection device 9, the toner supply port 8
The toner is supplied into the developing device from a.

One rotating shaft 5A of the supply roller 5 is fitted into a bearing member 51 and is rotatably supported. The bearing member 51 is inserted into the recess 1e of the developing device housing 1 and is positioned and fixed. Similarly, the other rotating shaft portion 5B of the supply roller 5 is fitted into the bearing member 52 and is rotatably supported. The bearing member 52 is inserted into the recess 1f of the developing device housing 1 and is positioned and fixed.

The rotating shaft 6A at one shaft end of the conveying screw 6 is fitted into a bearing member 61, and the rotating shaft 6B at the other shaft end is fitted into a bearing member 62. The conveying screw 6 is rotatably supported at both ends. I have. The rotating shaft portions 7A and 7B at both ends of the transport screw 7 are also fitted into bearing members 71 and 72, respectively, and both ends are rotatably supported.

FIG. 3 is a sectional view taken along line AA of the developing device shown in FIG. 2, and FIG. 4 is a sectional view taken along line BB of FIG.

Between the end of the blade portion 5C of the supply roller 5 and one bearing member 51, two lower ribs 1g formed between three partition walls (ribs) 1g which stand upright from the bottom of the developing device housing 1. The space portions 53A, 54A and the upper space portions 53B, 54B formed between three partition walls (ribs) 8g hanging from the inner surface of the top plate 8 are arranged.

When the top plate 8 is mounted and fixed on the developing device housing 1, a plurality of ribs 1g having a convex shape of the top plate 8
The semi-circular concave portion formed on the rib 1g and the semi-circular concave portion formed on the rib 8g face each other to fit into the concave plurality of ribs 8g of the developing device housing 1, and have a circular shape. None, the portion facing the rotating shaft portion 5A is a gap 55A, 55B, 5 having a circular ring shape for preventing developer from entering.
Form 5C. These three gaps 55A, 55B,
55C is set to a close distance of 1 mm or less, preferably about 0.2 mm, and prevents the developer from entering the bearing member 51.

By the rotation of the blade 5C of the supply roller 5,
The developer transported from the second transport chamber (developer accommodating portion) 1c in the direction of the rotary shaft 5A is prevented from passing by the gap 55A between the ribs 1g, 8g and the rotary shaft 5A.
The developer that has passed through 5A is stored in the spaces 53A and 53B. The developer in the first space portions 53A and 53B is
The gap 55B prevents entry into the bearing member 51. The developer that has passed through the gap 55A is accommodated in the second spaces 54A and 54B. Second space 54
The developer in A and 54B is blocked by the gap 55C, and prevents the developer from entering the bearing member 51. As described above, the multi-stage ribs 1g and 8g prevent the developer from entering the bearing member 51, and the multi-stage spaces 53 (A, B) and 54.
According to (A, B), since the developer that has passed through the multi-stage ribs 1g and 8g is stored, even if the developing device is used for a long time, the developer in the developer storage portion does not enter the bearing member 51. .

Similarly, on the outer periphery of the rotating shaft portion 5B between the end of the blade portion 5C of the supply roller 5 and the other bearing member 52, a lower portion formed between three partition walls (ribs) 1h is formed. 2
Space portions 56A, 57A and three partition walls (ribs) 8h
A plurality of upper space portions 56B and 57B formed therebetween are arranged.

The plurality of ribs 1h and 8h are fitted with each other,
An integral partition wall is formed, a circular through-hole is formed, and three spaces 58A, 58B, 58C for preventing the developer from entering are formed at portions facing the rotating shaft portion 5B. These gaps 58A, 58B, 58C are set to a close distance of 1 mm or less, preferably about 0.2 mm, and prevent the developer from entering the bearing member 52.

A plurality of ribs 1g, 8 for preventing developer from entering
g, 1h, 8h and a plurality of space portions 53 (A, B), 54
By installing (A, B), 56 (A, B), and 57 (A, B) near both ends of the blade portion 5C of the supply roller 5, the developer in the developing device housing 1 can be used as a bearing member 51, 5
The flow conveyed in the direction 2 is blocked. This allows
Problems such as an increase in rotational torque of the supply roller 5 and generation of abnormal noise are eliminated.

FIG. 5 is a sectional view of the developing device shown in FIG.

A rib and a space are also formed on the outer periphery of the rotation shafts 6A and 6B of the transport screw 6, similarly to the supply roller 5, so that the developer in the developer accommodating portion receives the bearing members 61 and 6 therefrom.
It is preventing you from entering 2.

That is, the partition is integrally formed by the two sets of ribs 1j and 8j, and two gaps 65A and 65B and one space 63A and 63B are formed on the outer periphery of the rotating shaft 6A. Further, a partition is integrally formed by three sets of ribs 1k and 8k, and three spaces 68A, 68B and 68C and two spaces 66A and 66 are provided on the outer periphery of the rotating shaft 6B.
B, 67A and 67B. The two spaces 66 (A, B) and 67 (A, B) correspond to the two spaces 56 (A, B) and 57 (A, B) of the supply roller 5.
It may be configured in common with B).

By providing a plurality of ribs 1j, 8j, 1k, 8k and a plurality of spaces 63 (A, B), 64 (A, B) near both ends of the conveying screw 6, the developing device housing 1 is provided. The flow in which the developer in the inside is conveyed toward the bearing members 61 and 62 is prevented. As a result, problems such as an increase in the rotational torque of the transport screw 6 and generation of an abnormal sound are solved.

A single space 73A is also formed on the outer periphery of one rotating shaft 7A of the conveying screw 7 by two ribs in the same manner as the supply roller 5 and the conveying screw 6, so that the developing portion in the developer accommodating portion is formed. This prevents the agent from entering the bearing member 71.

By providing a plurality of ribs and a plurality of spaces near both ends of the conveying screw 7, the flow of the developer in the developing device housing 1 in the direction of the bearing member is prevented. As a result, problems such as an increase in the rotation torque of the transport screw 7 and generation of an abnormal sound are solved.

[0035]

According to the developing device of the present invention, rotating members such as a developer supply member and a developer stirring / conveying member are smoothly driven and rotated with a light load continuously for a long time, thereby generating abnormal noise and developing. The occurrence of device failure is prevented.

[Brief description of the drawings]

FIG. 1 is a vertical sectional view of a developing device of the present invention.

FIG. 2 is a horizontal sectional view of the developing device.

FIG. 3 is a sectional view of the developing device taken along line AA in FIG. 2;

FIG. 4 is a sectional view of the developing device taken along line BB in FIG. 2;

FIG. 5 is a sectional view of the developing device taken along line CC in FIG. 2;

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Developing device housing (housing) 1b 1st conveyance chamber (developer accommodating part) 1c 2nd conveyance chamber (developer accommodating part) 1g, 1h, 1j, 1k, 8g, 8h, 8j, 8k Partition (rib) 2 developer carrier (developing sleeve) 5 developer supplying member (supply roller, rotating member) 51, 52, 61, 62, 71, 72 bearing member 5A, 5B, 6A, 6B, 7A, 7B rotating shaft 53A, 53B, 54A, 54B, 56A, 56B, 5
7A, 57B Space portions 63A, 63B, 66A, 66B, 67A, 67B, 7
3A Space 55A, 55B, 55C, 58A, 58B, 58C Gap 65A, 65B, 68A, 68B, 68C Gap 6,7 Developer stirring and conveying member (conveyor screw, rotating member) 8 Top plate (lid member) 10 Image holding Body (photoreceptor)

Claims (3)

[Claims] 1. A developer accommodating portion formed in a housing of a developing device, a developer carrying member for carrying a developer, a rotating member rotating in the developer accommodating portion, and a rotating shaft of the rotating member. And a bearing member rotatably supporting the developing device, so that the developer in the developer accommodating portion does not enter the bearing member between the rotating shaft portion of the rotating member and the bearing member. A developing device, wherein a partition wall and a space portion for preventing the developer from entering are formed in the housing. 2. The developing device according to claim 1, wherein the space is formed by the partition wall protruding from a housing of the developing device. 3. The stirring member according to claim 1, wherein the rotating member is a stirring and conveying member that stirs and conveys the developer accommodated in the developer accommodating portion of the developing device, and is disposed between the end of the stirring and conveying member and the bearing member. 3. The developing device according to claim 1, wherein a space for preventing the developer from entering is formed so that the developer does not enter the bearing member.