JP2002214906A - Developing device and image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a developing device by which the leakage of toner due to vibration at a feeding time and that due to the rotation and driving of a developing roller at the time of forming an image are effectively prevented and an image forming device provided with the developing device. SOLUTION: A sealing member 53 intervenes between the developing roller 31 and the lower aperture end part 52 of a housing 51, and a pressing plate 54 is inserted between the sealing member 53 and the lower aperture end part 52 before the use of a developing cartridge 29, and the pressing plate 53 is pulled out at the time of using the developing cartridge 29. Thus, sure sealing is attained because the sealing member 53 strongly presses the developing roller 31 during transportation such as a delivery time, and the leakage of the toner due to the shaving of the developing roller 31 is prevented because the sealing member 53 weakly presses the developing roller 31 at the time of forming the image.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a developing device such as a laser printer and an image forming apparatus.

[0002]

2. Description of the Related Art In an image forming apparatus such as a laser printer, a developing cartridge containing toner is usually removably mounted on an apparatus main body. The developing cartridge includes a toner storing section for storing toner and a developing roller for supporting toner supplied from the toner storing section. At the time of image formation, the developing cartridge is mounted on the main assembly of the apparatus. Is rotated to supply toner to the electrostatic latent image formed on the photosensitive drum to form a visible image, and this is transferred to paper to form an image.

In such a developing cartridge,
Since the developing roller is disposed so as to be exposed from the housing of the developing cartridge so as to face the photosensitive drum, the developing roller is disposed between the housing and the developing roller in order to prevent leakage of toner. A slidable sealing member is provided.

[0004]

However, in such a developing cartridge, in order to prevent leakage of toner from between the developing roller and the housing due to vibration during transportation during shipping or the like, a seal member is provided. It is effective to strongly press the developing roller. On the other hand, if the seal member is pressed too strongly against the developing roller, and the toner enters between the seal member and the developing roller due to the rotation of the developing roller during image formation, the developing roller is scraped by the toner. Or the developing roller is scraped by the sliding of the seal member itself,
On the contrary, a gap is created between the seal member and the developing roller, thereby causing a problem that the leakage of toner is enlarged. Therefore, in order to prevent the leakage of toner due to the rotational driving of the developing roller during image formation, it is preferable that the pressing force of the seal member against the developing roller is made slightly weaker than during the conveyance.

In order to effectively prevent the leakage of the toner due to the vibration during the conveyance, the leakage of the toner occurs due to the rotational driving of the developing roller at the time of forming the image, and the rotational driving of the developing roller at the time of forming the image. It is difficult to effectively prevent toner leakage due to vibration during transport when trying to prevent toner leakage due to vibration.

For this reason, for example, it is conceivable to form the seal member using a material such as Teflon (registered trademark) felt that has good slidability and can entangle the toner well. Even if such a seal member is used, it is still difficult to effectively prevent toner leakage from the time of conveyance to the time of image formation.

In particular, when a polymerized toner having excellent fluidity is used to improve the image quality, it is extremely difficult to prevent such leakage of the toner.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has as its object to prevent toner leakage due to vibration during conveyance, and toner leakage due to rotational driving of a developing roller during image formation. It is an object of the present invention to provide a developing device capable of effectively preventing both of them, and an image forming apparatus including such a developing device.

[0009]

In order to achieve the above object, according to the first aspect of the present invention, in a developing device having a moving member which moves at the time of image formation, the developing member is sealed by pressing the moving member. It is characterized by including a seal member, and a pressing switching means for switching a pressing force of the sealing member against the moving member.

According to such a configuration, the pressing force of the seal member against the moving member can be switched by the pressing switching means. Therefore, at the time of transportation in shipping or the like, the pressing force of the sealing member against the moving member is increased by the pressing switching means. As a result, leakage of the developer due to vibration during transport can be effectively prevented by a reliable seal, and
At the time of moving the moving member at the time of image formation, the pressing force of the seal member against the moving member is slightly weakened by the pressing switching means, even when the developer enters between the sealing member and the moving member, By preventing the moving member from being scraped by the developer or the sliding member being rubbed by the seal member itself, it is possible to effectively prevent leakage of the developer during image formation. Therefore, by appropriately switching the pressing force by the pressing switching unit, it is possible to effectively prevent toner from leaking from the time of conveyance to the time of image formation.

The invention described in claim 2 is the first invention.
In the invention described in (1), the seal member presses the moving member more strongly before using the developing device, and presses the moving member more weakly during use by the pressing switching unit.

According to such a configuration, the sealing member is
The pressure switching means presses the moving member more strongly before use of the developing device, and more weakly presses the moving member at the time of use. The seal can effectively prevent the developer from leaking due to vibration during conveyance, and when moving the moving member during image formation,
Even when the sealing member presses the moving member more weakly and the developer enters between the sealing member and the moving member, the moving member is scraped by the developer or moved by sliding of the sealing member itself. By preventing the members from being scraped, it is possible to effectively prevent leakage of the developer during image formation. In this way, the sealing member presses the moving member more strongly before using the developing device, and presses the moving member more weakly during use, thereby effectively preventing toner leakage from the time of conveyance to the time of image formation. can do.

[0013] Further, the invention according to claim 3 is based on claim 2.
In the invention described in the above, the pressing switching means is arranged in the developing device so as to press the seal member before using the developing device, and is removed from the developing device when used. I have.

According to such a configuration, the pressing switching means is disposed in the developing device at the time of transportation during shipping and the like, and is removed from the developing device at the time of image formation. Pressure can be switched. Therefore, with a simple configuration,
Leakage of toner can be reliably prevented from the time of conveyance to the time of image formation.

The invention described in claim 4 is the same as the claim 3.
In the invention described in the above, the pressing switching means is inserted between the housing of the developing device and the seal member before using the developing device, and the housing of the developing device is used when the developing device is used. It is characterized in that it can be pulled out from between the body and the seal member.

According to such a configuration, the pressing switching means is inserted between the housing of the developing device and the sealing member during transportation during shipping or the like, and between the housing of the developing device and the sealing member during image formation. By pressing the seal member, the pressing force of the seal member against the moving member can be easily and reliably switched. Therefore,
With a simple configuration, it is possible to reliably prevent toner leakage from the time of conveyance to the time of image formation.

The invention described in claim 5 is the first invention.
The invention according to any one of the first to fourth aspects, wherein the moving member is a developing roller including a roller made of an elastic body.

The roller of the developing roller is preferably formed of an elastic body in order to reduce damage to the photosensitive member and the developer. However, when the roller is formed of an elastic body, for example, it is formed of a sponge body. As in the case, leakage of the developer due to vibration during conveyance from between the developing roller and the seal member cannot be blocked, and leakage of the developer is likely to occur. Further, when the roller is formed of an elastic body, unlike the case of forming the roller with metal, for example, it is not possible to prevent the developing roller from being scraped, and the developer is likely to leak during image formation.

However, in the present invention, since the pressing force of the seal member against the developing roller can be appropriately switched by the pressing switching means, even if the roller of the developing roller is formed of an elastic body, the leakage of the developer is prevented. It can be effectively prevented. Therefore, it is possible to effectively prevent the leakage of the developer while forming a favorable image formation by forming the roller of the developing roller with an elastic body.

Further, the invention according to claim 6 is the invention according to claim 1.
In the invention according to any one of the first to fifth aspects, the seal member includes a film member that contacts the moving member,
It is characterized by being provided so as to extend in the longitudinal direction of the moving member.

According to such a configuration, since the film member comes into contact with the moving member, the bending of the film member causes the pressing force switched by the pressing switching means to be applied.
The moving member can be reliably pressed. In particular, in the case of a film member, it is difficult to prevent the developer from leaking due to vibration at the time of transport from the moving member. Leakage can be prevented. Therefore, leakage of toner can be more reliably prevented from the time of conveyance to the time of image formation. Moreover, since the seal member is provided so as to extend in the longitudinal direction of the moving member, it is difficult to prevent the developer from leaking in the circumferential direction of the moving member. It is possible to more reliably prevent the developer from leaking over the longitudinal direction of the member.

The invention described in claim 7 is the same as the invention in claim 6
In the invention described in (1), the seal member includes an elastic member provided below the film member in a longitudinal direction of the film member.

According to such a configuration, the pressing force switched by the pressing switching means can be transmitted to the film member via the elastic member, so that the pressing force is always elastically applied to the film member. it can. Therefore, the pressing force can be uniformly applied to the moving member by the film member, and the leakage of the toner can be more reliably prevented.

The invention described in claim 8 is the first invention.
The invention according to any one of the first to seventh aspects, wherein the pressing switching means is formed integrally with a packaging member for packaging the developing device.

According to such a configuration, when the developing device is opened from the state of being wrapped by the wrapping member, the pressing switching means can be automatically removed, so that the moving member of the seal member can be easily and reliably. Can be switched.

According to a ninth aspect of the present invention, an image forming apparatus includes the developing device according to any one of the first to eighth aspects.

By providing such a developing device, since the developer is prevented from being scattered into the device, reliable operation of the device is ensured, and good image formation can be achieved.

According to a tenth aspect of the present invention, in the ninth aspect, the developing device is detachably mounted on the image forming apparatus, and the moving member is
When the developing device is mounted on the image forming apparatus,
It is characterized in that the developing device is pressed more weakly by the seal member than when the developing device is not mounted on the image forming apparatus.

According to such a configuration, when the developing device is mounted on the image forming apparatus, the moving member is pressed less by the seal member than when the developing device is not mounted on the image forming device. In some cases, if the pressing force of the seal member against the moving member is increased, the leakage of the developer during conveyance can be effectively prevented by a reliable seal, and the developing device is mounted on the image forming apparatus. At times, the pressing force of the seal member against the moving member becomes weaker. Therefore, even if the developer enters between the seal member and the moving member, the moving member is scraped by the developer, or the seal member itself slides. The moving member is prevented from being scraped by the rubbing, whereby the leakage of the developer at the time of image formation can be effectively prevented.

[0030]

FIG. 1 is a side sectional view showing a main part of an embodiment of a laser printer as an image forming apparatus according to the present invention. In FIG. 1, a laser printer 1 includes a feeder unit 4 for feeding paper 3 in a main body casing 2.
And an image forming unit 5 for forming a predetermined image on the fed paper 3.

The feeder unit 4 includes a paper feed tray 6 detachably mounted on the bottom of the main body casing 2, a paper pressing plate 7 provided in the paper feed tray 6, and one end of the paper feed tray 6. A paper feed roller 8 and a paper feed pad 9 provided above the end; paper dust removal rollers 10 and 11 provided downstream of the paper feed roller 8 in the transport direction of the sheet 3; 11 is provided with a registration roller 12 provided on the downstream side in the transport direction of the paper 3.

The sheet pressing plate 7 is capable of stacking the sheets 3 in a stacked manner, and is supported so as to be swingable at an end remote from the paper feed roller 8 so that the end closer to the paper feed roller 8 can be moved up and down. And is urged upward by a spring (not shown) from the back side. Therefore, the sheet pressing plate 7 swings downward against the urging force of the spring with the end farther from the sheet feeding roller 8 as a fulcrum, as the amount of stacked sheets 3 increases. The paper feed roller 8 and the paper feed pad 9 are arranged to face each other, and the paper feed pad 9 is pressed toward the paper feed roller 8 by a spring 13 provided on the back side of the paper feed pad 9. . The uppermost sheet 3 on the sheet pressing plate 7 is fed from the back side of the sheet pressing plate 7 by a spring (not shown) to a feed roller 8.
, And the paper is fed one by one after being sandwiched between the paper feed roller 8 and the paper feed pad 9 by the rotation of the paper feed roller 8. The fed paper 3 is fed to a paper dust removal roller 10.
After the paper dust is removed by (11) and (11), the paper is sent to the registration roller 12. The registration roller 12 is composed of a pair of rollers, and sends the sheet 3 to the image forming unit 5 after a predetermined registration.

The feeder unit 4 further includes a multi-purpose tray 14, a multi-purpose side paper feed roller 15 for feeding the paper 3 stacked on the multi-purpose tray 14, and a multi-purpose side paper feed pad. 25
The multi-purpose paper feed roller 15 and the multi-purpose paper feed pad 25 are arranged to face each other, and a multi-purpose paper feed roller 25 and a multi-purpose paper feed pad 25 The purpose-side paper feed pad 25 is pressed toward the multi-purpose side paper feed roller 15. The paper 3 stacked on the multi-purpose tray 14 is sandwiched between the multi-purpose paper feed roller 15 and the multi-purpose paper feed pad 25 by the rotation of the multi-purpose paper feed roller 15, and then fed one by one. Paper.

The image forming section 5 includes a scanner unit 16,
A process unit 17 and a fixing unit 18 are provided.

The scanner unit 16 is provided at an upper part in the main body casing 2 and has a laser emitting unit (not shown),
A polygon mirror 19, which is driven to rotate, lenses 20 and 21, reflection mirrors 22, 23 and 24, etc.
A laser beam based on predetermined image data emitted from the laser emitting unit is indicated by a chain line as shown by a polygon mirror 19, a lens 20, reflection mirrors 22 and 23, and a lens 2.
1. The light passes through or is reflected in the order of the reflecting mirror 24, and irradiates the surface of the photosensitive drum 27 of the process unit 17 described later by high-speed scanning.

The process unit 17 is disposed below the scanner unit 16 and, as shown in FIG. 2, includes a photosensitive drum 27 and a developing device in a drum cartridge 26 detachably mounted on the main body casing 2. , A scorotron charger 29, and a transfer roller 30.

The developing cartridge 28 is detachably mounted on the drum cartridge 26, and includes a developing roller 31, a layer thickness regulating blade 32, a supply roller 33, a toner container 34, and the like as moving members.

In the toner container 34, as a developer,
A positively charged non-magnetic one-component toner is filled. Examples of the toner include polymerizable monomers such as styrene-based monomers such as styrene, acrylic acid, alkyl (C
Polymerized toners obtained by copolymerizing acrylic monomers such as 1-C4) acrylates and alkyl (C1-C4) methacrylates by known polymerization methods such as suspension polymerization are used. Such a polymerized toner is spherical, has extremely good fluidity, and can form a high-quality image. In addition, such a toner is blended with a coloring agent such as carbon black, a wax, and the like, and an external additive such as silica is added in order to improve fluidity. The particle size is about 6 to 10 μm.

The toner in the toner container 34 is
The agitator 36, which is supported by a rotation shaft 35 provided at the center of the toner container 34, is rotated in the direction of the arrow (clockwise) to be agitated, so that the agitator 36 is moved from the toner supply port 37 opened to the side of the toner container 34. Released. In addition, a window 38 for detecting the remaining amount of toner is provided on a side wall of the toner storage unit 34, and the toner is cleaned by a cleaner 39 supported on the rotating shaft 35.

A supply roller 33 is provided at a position lateral to the toner supply port 37 so as to be rotatable in the direction of the arrow (counterclockwise), and the developing roller 31 is opposed to the supply roller 33. It is arranged to be rotatable in the direction of the arrow (counterclockwise). The supply roller 33 and the developing roller 31 are in contact with each other so that each of them is compressed to some extent.

The supply roller 33 is connected to a metal roller shaft.
A roller made of a conductive sponge body is covered.

The developing roller 31 has a metal roller shaft,
A roller made of an elastic body made of a conductive rubber material is covered. More specifically, the roller of the developing roller 31 is formed by coating the surface of a roller body made of conductive urethane rubber or silicone rubber containing fine carbon particles with a coat layer of urethane rubber or silicone rubber containing fluorine. Have been. Note that a predetermined developing bias is applied to the developing roller 31 with respect to the photosensitive drum 27.

In the vicinity of the developing roller 31, a layer thickness regulating blade 32 is provided. The layer thickness regulating blade 32 has a pressing portion 40 having a semicircular cross section made of insulating silicone rubber at the tip of a blade body made of a metal leaf spring material. 28 is supported by the housing 51 of the developing roller 31, and the pressing portion 40
It is configured to be pressed against the top.

The toner discharged from the toner supply port 37 is supplied to the developing roller 3 by the rotation of the supply roller 33.
1, the supply roller 33 and the developing roller 3
1 is positively triboelectrically charged, and the developing roller 31
The toner supplied above is pressed by the pressing portion 40 of the layer thickness regulating blade 32 and the developing roller 3 with the rotation of the developing roller 31.
1 and is further triboelectrically charged and carried on the developing roller 31 as a thin layer having a constant thickness.

The photosensitive drum 27 is disposed at a position lateral to the developing roller 31 so as to be rotatable in the direction of the arrow (clockwise) so as to face the developing roller 31. The photosensitive drum 27 has a drum body grounded and a surface portion formed of a positively charged photosensitive layer made of polycarbonate or the like.

The scorotron charger 29 is arranged above the photosensitive drum 27 at a predetermined interval so as not to contact the photosensitive drum 27. The scorotron charger 29 is a positive scorotron charger for generating corona discharge from a charging wire such as tungsten, and is configured to uniformly charge the surface of the photosensitive drum 27 to a positive polarity. ing.

The surface of the photosensitive drum 27 is first uniformly charged positively by the scorotron charger 29 with the rotation of the photosensitive drum 27, and then the laser beam from the scanner unit 16 is scanned at high speed. To form an electrostatic latent image based on predetermined image data.

Next, the rotation of the developing roller 31 causes the positively-charged toner carried on the developing roller 31 to come into contact with the photosensitive drum 27 so as to form a static image formed on the surface of the photosensitive drum 27. The latent image is supplied to an exposed portion of the surface of the photosensitive drum 27, which is uniformly positively charged and has a lowered potential after being exposed to a laser beam, and is selectively carried, thereby forming a visible image. Thereby, reversal development is achieved.

The transfer roller 30 is disposed below the photosensitive drum 27 so as to oppose the photosensitive drum 27, and is positioned in the direction indicated by the arrow (counterclockwise) in the drum cartridge 26.
It is supported rotatably. This transfer roller 30
A metal roller shaft is covered with a roller made of a conductive rubber material, and a predetermined transfer bias is applied to the photosensitive drum 27 during transfer. Therefore, the visible image carried on the surface of the photosensitive drum 27 is transferred to the sheet 3 while the sheet 3 passes between the photosensitive drum 27 and the transfer roller 30.

As shown in FIG. 1, the fixing section 18 is disposed on the downstream side of the process unit 17 and
1, a pressing roller 42 for pressing the heating roller 41, and a pair of transport rollers 43 provided downstream of the heating roller 41 and the pressing roller 42. The heating roller 41 is made of metal and includes a halogen lamp for heating. The heating roller 41 transfers the toner transferred onto the sheet 3 in the process unit 17 while the sheet 3 passes between the heating roller 41 and the pressing roller 42. Heat-fixed, then
The sheet 3 is conveyed to a sheet discharge path 44 by a conveying roller 43. The sheet 3 sent to the sheet ejection path 44 is sent to a sheet ejection roller 45, and the sheet ejection roller 45
As a result, the paper is discharged onto the paper discharge tray 46.

The laser printer 1 has a paper 3
In order to form an image on both sides, a reverse transport unit 47 is provided. The reversing conveyance section 47 includes a discharge roller 45
, A reverse transport path 48, a flapper 49, and a plurality of reverse transport rollers 50.

The paper discharge roller 45 is composed of a pair of rollers, and is configured to be able to switch between normal rotation and reverse rotation. As described above, this paper discharge roller 45
When the paper 3 is discharged onto the paper discharge tray 46, the paper rotates in the forward direction. When the paper 3 is reversed, the paper 3 rotates in the reverse direction.

The reverse transport path 48 is provided along the vertical direction so that the sheet 3 can be transported from the paper discharge roller 45 to a plurality of reverse transport rollers 50 disposed below the image forming unit 5. The upstream end thereof is disposed near the paper discharge roller 45, and the downstream end thereof is disposed near the reversing conveyance roller 50.

The flapper 49 is swingably provided so as to reach a branch portion between the paper discharge path 44 and the reverse transport path 48. The flapper 49 is inverted by a paper discharge roller 45 by excitation or non-excitation of a solenoid (not shown). The transport direction of the fed sheet 3 can be switched from the direction toward the discharge path 44 to the direction toward the reverse transport path 48.

A plurality of reverse transport rollers 50 are provided in a substantially horizontal direction above the paper feed tray 6, and the most upstream reverse transport roller 50 is disposed near the rear end of the reverse transport path 48. In addition, the most downstream reverse transport roller 50 is provided below the registration roller 12.

When an image is formed on both sides of the sheet 3, the reverse transport unit 47 is operated as follows. That is, the paper 3 on which an image is formed on one surface is transferred from the discharge path 44 to the discharge rollers 45 by the transport rollers 43.
The paper discharge roller 45 rotates forward while sandwiching the paper 3, and once conveys the paper 3 toward the outside (the paper discharge tray 46 side). When the sheet 3 is sent to the outside and the rear end of the sheet 3 is sandwiched by the sheet ejection rollers 45, the normal rotation is stopped. Next, the paper discharge roller 45 rotates in the reverse direction, and the flapper 49
8 so that the paper 3 is conveyed.
Is transported to the reverse transport path 48 in a state of being reversed. When the conveyance of the sheet 3 is completed, the flapper 49 is switched to the original state, that is, the state in which the sheet 3 sent from the conveying roller 43 is sent to the sheet discharging roller 45. Next, the sheet 3 transported in the reverse direction to the reverse transport path 48 is transported to the reverse transport roller 50, from which the paper 3 is inverted upward and sent to the registration roller 12. The paper 3 conveyed to the registration rollers 12 is again turned over, and after a predetermined registration, is sent to the image forming unit 5 again, whereby a predetermined image is formed on both sides of the paper 3.

In the laser printer 1, the photosensitive drum 2 is transferred to the sheet 3 by the transfer roller 30.
The remaining toner remaining on the surface of the developing roller 7 is collected by a developing roller 31 by a so-called cleanerless method. If the residual toner on the surface of the photosensitive drum 27 is collected by such a cleanerless method, there is no need to provide a cleaning device such as a blade or a storage means for waste toner. Reduction can be achieved.

The developing cartridge 28 of the laser printer 1 employs a seal structure described below to prevent toner from leaking between the developing roller 31 and the housing 51 of the developing cartridge 28. I have.

That is, as shown in FIG. 3 and FIG. 4, the sealing structure comprises a developing roller 31 and a housing 51 disposed below the developing roller 31 with a slight gap therebetween.
A seal member 53 is interposed between the developing cartridge 28 and the lower opening end 52 of the developing cartridge 28, as shown in FIGS. Is configured by inserting a pressing plate 54 as pressing switching means for switching the pressing force of the sealing member 53 against the developing roller 31 between the sealing member 53 and the lower opening end 52.

In this sealing structure, as shown in FIGS. 7 and 8, a side seal formed of a sponge body elastically in contact with the peripheral surface of the developing roller 31 around both ends in the longitudinal direction of the developing roller 31. The side seals 56 prevent toner from leaking from both sides of the developing roller 31. As shown in FIGS. 3 and 4, the pressing portion 40 of the layer thickness regulating blade 32 is pressed against the side of the developing roller 31, so that the toner in the developing cartridge 28 The pressing portion 40 of the layer thickness regulating blade 32 is securely sealed by a sealing member 53 described in detail below.

The housing 51 of the developing cartridge 28 is
As shown in FIG. 4, in order to expose the developing roller 31 to face the photosensitive drum 27, a side end where the developing roller 31 is disposed is opened, and an opening portion of the housing 51 is provided. The lower opening end 52 is formed so as to be inclined upward from the edge toward the lower side of the developing roller 31, and the lower opening end 52 and the developing roller 3 are formed.
1 and a slight gap is formed. Also,
From the edge of the lower opening end 52 to the developing roller 31
An insertion opening 55 for inserting a pressing plate 54 described later along an oblique direction in which the lower opening end 52 extends extends in the middle of the direction extending downward. An opening is formed over the length in which 53 is provided.

As shown in FIGS. 7 and 8, the seal member 53 is provided between side seals 56 provided on both longitudinal sides of the developing roller 31 in the gap between the lower opening end 52 and the developing roller 31. Developing roller 3
1, and as shown in FIGS. 5 and 6, a leaf spring member 57, a film member 58,
A sponge intermediate member 59 and a sponge end member 60 as elastic members are provided.

As shown in FIGS. 7 and 8, the leaf spring member 57 is disposed in a lateral direction corresponding to the distance between the two side seals 56 (the direction along the longitudinal direction of the developing roller 31; the same applies hereinafter).
5 and 6 are made of a metal plate member having a width of
As shown in FIG. 5, one end 61 of the vertical direction (the direction along the rotation direction of the developing roller 31; the same applies hereinafter) is supported and fixed at an outer portion 62 closer to the edge of the lower opening end 52 than the insertion opening 55. And the other end 63 in the vertical direction.
Are arranged so as to be interposed between the developing roller 31 and the inner portion 64 of the lower opening end 52 closer to the developing roller 31 than the insertion opening 55. The leaf spring member 57 has a stepped portion 6 which is depressed downward in the middle of the vertical direction.
5 is bent, and the other end 63 is formed so as to always face the inner side 64 of the lower opening end 52 by elastic force.

As shown in FIGS. 7 and 8, the film member 58 is made of a flexible resin film having a width in the horizontal direction corresponding to the distance between both side seals 56.
As shown in FIG. 6 and FIG.
It is adhered onto a leaf spring member 57 supported and fixed at an outer portion 62 of the lower opening end 52, and the other end 67 in the vertical direction is connected to the developing roller 31 and the leaf spring member 57.
Is arranged so as to be interposed between the other end portion 63 of the second member.

The sponge intermediate member 59 is shown in FIGS.
As shown in FIG. 5, a rectangular sponge body having a width in the lateral direction corresponding to the distance between the two side seals 56, and as shown in FIGS.
3 and the other end 67 of the film member 58 are interposed in a compressed state.

The sponge end member 60 is formed of a rectangular sponge member having a width in the lateral direction corresponding to the distance between the two side seals 56. As shown in FIGS.
The other end 63 of the leaf spring member 57 and the sponge intermediate member 5
9, the lower surface thereof is fixed to the inner portion 64 of the lower opening end 52, and the upper surface thereof is in contact with the other end of the other end 67 of the film member 58. are doing.

In this sealing structure, as described above, for example, during transportation during shipping, etc.
Before using the developing cartridge 28, a pressing plate 54 is inserted between the sealing member 53 and the lower opening end 52 as shown in FIGS.

The pressing plate 54 has a width in the horizontal direction corresponding to the distance between the two side seals 56 as shown in FIG. 7, and has a substantially L-shaped cross section as shown in FIG. The leaf spring member 5 is inserted through the insertion opening 55 of the lower opening end 52.
7 is inserted along the diagonal direction in which the lower opening end 52 extends between the other end 63 of the base 7 and the inner side 64 of the lower opening end 52 until the sponge end member 60 abuts.

By inserting the pressing plate 54 in this manner, the sponge intermediate member 59 is compressed against the elastic force of the other end portion 63 of the leaf spring member 57, whereby
The film member 58 is strongly pressed toward the developing roller 31. For this reason, at the time of conveyance during shipping or the like, the film member 58 of the seal member 53 strongly presses the developing roller 31 to achieve a reliable seal, thereby effectively preventing toner leakage due to vibration during conveyance. can do.

In this seal structure, when the developing cartridge 28 is mounted on the drum cartridge 26 mounted on the main body casing 2 during use,
The pressing plate 54 is pulled out from the insertion opening 55 of the lower opening end 52. Then, as shown in FIGS. 4, 6, and 8, the other end 63 of the leaf spring member 57 is moved by the elastic force.
Since the sponge intermediate member 59 is deformed toward the inner portion 64 of the lower opening end portion 52, the compressed state of the sponge intermediate member 59 is released, so that the film member 58 is weaker than when the pressing plate 54 is inserted toward the developing roller 31. Becomes pressed. Therefore, even if toner enters between the film member 58 of the seal member 53 and the developing roller 31 due to the rotational driving of the developing roller 31 during image formation, the developing roller 31 is scraped by the toner, or the film member 58 itself is removed. This prevents the developing roller 31 from being scraped by the rubbing, so that toner leakage during image formation can be effectively prevented. In particular, since the laser printer 1 uses a non-magnetic one-component toner, the film member 58 of the seal member 53 is rotated by the rotation of the developing roller 31 at the time of image formation as compared with the toner constrained by magnetism. Although the toner easily enters between the developing roller 31 and the developing roller 31, such a sealing structure can effectively prevent the developing roller 31 from being scraped, thereby reliably preventing leakage of the toner.

In order to pull out the pressing plate 54, for example, a contact member that comes into contact with the pressing plate 54 is provided on the drum cartridge 26, and when the developing cartridge 28 is mounted, the pressing plate 54 is used as a contact member. By pressing the pressing plate 54, the pressing plate 54 may be automatically retracted from the insertion opening 55 of the lower opening end 52, and the pressing plate 54 may be configured to be automatically pulled out. Further, the user may manually pull out the pressing plate 54.

Further, as shown in FIGS. 9 and 10,
When the pressing plate 54 is formed integrally with a packaging cover 68 as a packaging member for packaging the developing cartridge 28, when the developing cartridge 28 is opened from the state of being packaged by the packaging cover 68, Pressing plate 54
It may be automatically removed together with the packaging cover 68. That is, as shown in FIGS. 9 and 10, the packaging cover 68 includes a front cover 69 that covers the entire surface of the developing roller 31 on the exposed side (the side facing the photosensitive drum 27). The pressing plate 54 is formed continuously and integrally, and the upper end thereof is bent to be locked to the mounting member of the layer thickness regulating blade 32. Further, from both sides in the lateral direction of the front cover 69, a side plate 71 in which a substantially U-shaped locking hole 70 for locking to the roller shaft of the developing roller 31 is formed continuously and integrally bent. .

When the developing cartridge 28 is packaged by the packaging cover 68, the pressing plate 5 formed integrally with the lower end of the front cover 69 is formed.
4 is inserted between the other end 63 of the leaf spring member 57 and the inner side 64 of the lower opening end 52 from the insertion opening 55 of the lower opening end 52, and the upper end of the front cover 69 is It is locked to a mounting member of the layer thickness regulating blade 32, and locking holes 71 of both side plates 71 are fitted to both shaft ends of the roller shaft of the developing roller 31.

Next, when the packaging cover 68 is to be removed from the developing cartridge 28 when the developing cartridge 28 is used, both side plates 71 are bent outward and fitted to both shaft ends of the roller shaft of the developing roller 31. After releasing the locking of the locking hole 70, the front cover 69 is pulled forward, and the packaging cover 68
At the same time, the pressing plate 54 is automatically pulled out of the insertion opening 55 of the lower opening end 52. Accordingly, the pressing plate 54 can be automatically removed together with the packaging cover 68, so that the pressing force of the seal member 53 against the developing roller 31 can be easily and reliably switched.

Therefore, with such a seal structure, it is possible to effectively prevent toner from leaking from the time of conveyance to the time of image formation. In particular, the laser printer 1 uses a polymerized toner having a very high fluidity compared to the pulverized toner, so that it is vibrated during transportation during shipping or the like, or is driven to rotate the developing roller 31 during image formation. As a result, such polymerized toner is likely to leak from between the film member 58 of the seal member 53 and the developing roller 31, but such a seal structure can easily and reliably prevent the polymerized toner from leaking. Can be.

Further, in this sealing structure, before the developing cartridge 28 is used, the pressing plate 54 is moved to the lower open end 5.
2 is inserted between the other end 63 of the leaf spring member 57 of the developing cartridge 28 and the inner side 64 of the lower opening end 52 of the developing cartridge 28 so as to insert the lower opening end 52 during use. The pressing force of the film member 58 against the developing roller 31 of the sealing member 53 can be easily and reliably switched only by pulling it out from the opening 55 and removing it. Leakage can be reliably prevented.

The laser printer 1 employs a non-magnetic one-component developing method, and the roller of the developing roller 31 is formed of an elastic material in order to reduce damage to the toner and the photosensitive drum 27. . Therefore, unlike the case where the roller of the developing roller 31 is formed of a sponge body, the leakage of the toner due to the vibration at the time of conveyance from between the developing roller 31 and the seal member 53 cannot be blocked, and the leakage is likely to occur. . Further, when the roller is formed of an elastic body, for example, unlike the case where the roller is formed of metal, it is not possible to prevent the developing roller 31 from being scraped, and the toner is likely to leak during image formation. However, according to such a seal structure, the pressing force of the film member 58 of the seal member 53 against the developing roller 31 can be appropriately switched, so that even if the roller of the developing roller 31 is formed of an elastic body, the leakage of the toner is prevented. Can be effectively prevented. For this reason, the roller of the developing roller 31 is formed of an elastic body, and the non-magnetic one-component developing method achieves good image formation with a simple configuration that does not require a toner concentration sensor and the like, while preventing toner leakage. Effectiveness can be prevented.

Further, in this sealing structure, since the flexible film member 58 comes into contact with the developing roller 31, the bending of the film member 58 causes the pressing plate 5 to move.
The developing roller 31 can be surely pressed with an appropriate pressing force corresponding to each of the time of insertion and the time of removal of the developing roller 4. In particular, in the film member 58, the developing roller 3
Although it is difficult to prevent the toner from leaking due to vibration during the conveyance from the position 1, such a leakage of the toner can be prevented by increasing the pressing force during the conveyance. Therefore, leakage of toner can be more reliably prevented from the time of conveyance to the time of image formation.

Further, since the seal member 53 is provided in the longitudinal direction of the developing roller 31 so as to be adjacent to the side seals 56 provided on both sides in the longitudinal direction of the developing roller 31, Although it is difficult to prevent the toner from leaking to the developing roller, by appropriately switching the pressing force, the toner is prevented from leaking in the longitudinal direction of the developing roller 31 more reliably.

Further, in the sealing member 53, the pressing force corresponding to each of the insertion and the removal of the pressing plate 54 is transmitted to the film member 58 via the sponge intermediate member 59. Is
The pressing force can always be applied elastically. for that reason,
The film member 58 can apply a uniform pressing force to the developing roller 31, thereby further reliably preventing toner from leaking.

Therefore, in this laser printer 1,
Since the toner in the developing cartridge 28 is prevented from being scattered into the main body casing, reliable operation of the apparatus is ensured, and excellent image formation can be achieved.

In the embodiment described above, the pressing plate 54 is inserted into the insertion opening 5 of the lower opening end 52 before use.
In the present invention, the term “before use” refers to a state where the developing cartridge 28 is not mounted on the laser printer 1, and includes a state where the developing cartridge 28 is once mounted and then removed again.

The seal member 53 does not necessarily need to be provided over the longitudinal direction of the developing roller 31, and may be provided only at both ends of the developing roller 31 depending on the purpose and use.

In the above-described embodiment, the seal structure is applied to the developing roller 31. However, the moving member of the present invention is not particularly limited as long as it is a moving member.
The member is not limited to one, and may be a member having a bearing and driven to rotate, for example, a supply roller 33 or an agitator 36. Further, the pressing switching means of the present invention is not particularly limited to the pressing plate 54 as long as it is a member that can switch the pressing force. For example, the pressing force is switched by switching the urging force of a spring. The configuration may be any.

[0085]

As described above, according to the first aspect of the present invention, by appropriately switching the pressing force by the pressing switching means, it is possible to effectively prevent the leakage of toner from the time of conveyance to the time of image formation. Can be.

According to the second aspect of the present invention, the seal member presses the moving member more strongly before using the developing device,
By pressing the moving member more weakly during use, it is possible to effectively prevent toner leakage from the time of conveyance to the time of image formation.

According to the third aspect of the invention, with a simple configuration, it is possible to reliably prevent toner from leaking from the time of conveyance to the time of image formation.

According to the fourth aspect of the present invention, leakage of toner can be reliably prevented from the time of conveyance to the time of image formation with a simpler configuration.

According to the fifth aspect of the present invention, it is possible to form the roller of the developing roller with an elastic body and to effectively prevent leakage of the developer while achieving good image formation.

According to the sixth aspect of the invention, it is possible to more reliably prevent the leakage of toner from the time of conveyance to the time of image formation, in the longitudinal direction of the developing roller.

According to the seventh aspect of the present invention, the pressing force can be uniformly applied to the moving member by the film member, and the leakage of the toner can be more reliably prevented.

According to the eighth aspect of the present invention, since the pressing switching means can be automatically removed, the pressing force of the seal member against the moving member can be easily and reliably switched.

According to the ninth aspect of the present invention, since the developer is prevented from being scattered in the apparatus, reliable operation of the apparatus is ensured, and good image formation can be achieved.

According to the tenth aspect of the present invention, it is possible to effectively prevent the developer from leaking at the time of conveyance, and to effectively prevent the developer from leaking during image formation.

[Brief description of the drawings]

FIG. 1 is a side sectional view showing a main part of an embodiment of a laser printer as an image forming apparatus of the present invention.

FIG. 2 is a side sectional view showing a main part of a process unit of the laser printer shown in FIG.

FIG. 3 is a side sectional view of a main part showing a developing cartridge (in a state where a pressing plate is inserted) of the process unit shown in FIG. 2;

FIG. 4 is a side sectional view of a main part showing a developing cartridge (in a state where a pressing plate is pulled out) of the process unit shown in FIG. 2;

FIG. 5 is a sectional side view of a main part showing a seal member (in a state where a pressing plate is inserted) of the developing cartridge shown in FIG. 3;

6 is a sectional side view of a main part showing a seal member (in a state where the pressing plate is pulled out) of the developing cartridge shown in FIG. 4;

7 is a plan cross-sectional view of a main part showing a seal member (in a state where a pressing plate is inserted) of the developing cartridge shown in FIG. 3;

8 is a plan cross-sectional view of a main part showing a seal member (with the pressing plate pulled out) of the developing cartridge shown in FIG. 4;

9 is a side sectional view of a main part showing a state where a packaging cover of the developing cartridge shown in FIG. 3 is mounted.

10 is a cross-sectional plan view of a main part showing a state where the packaging cover of the developing cartridge shown in FIG. 7 is mounted.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Laser printer 28 Developing cartridge 31 Developing roller 51 Housing 53 Seal member 54 Press plate 58 Film member 68 Packaging cover

Claims (10)

[Claims] 1. A developing device including a moving member that moves during image formation, a seal member that presses the moving member to seal a developer, and a pressure switching unit that switches a pressing force of the seal member against the moving member. Characterized by having
Developing device. 2. The method according to claim 1, wherein the pressure switching unit presses the moving member more strongly before using the developing device, and presses the moving member more weakly during use. Item 2. The developing device according to Item 1. 3. The device according to claim 1, wherein the pressing switch is disposed in the developing device so as to press the seal member before using the developing device, and is removed from the developing device in use. The developing device according to claim 2. 4. The pressing switch means is inserted between the housing of the developing device and the seal member before using the developing device, and the housing of the developing device is used when the developing device is used. The developing device according to claim 3, wherein the developing device is configured to be able to be pulled out from between the seal member and the seal member. 5. The apparatus according to claim 1, wherein the moving member is a developing roller including a roller made of an elastic body.
5. The developing device according to any one of items 1 to 4. 6. The device according to claim 1, wherein the seal member includes a film member that comes into contact with the moving member, and is provided to extend in a longitudinal direction of the moving member.
6. The developing device according to any one of items 5 to 5. 7. The sealing member according to claim 6, wherein an elastic member is provided below the film member in a longitudinal direction of the film member.
3. The developing device according to claim 1. 8. The developing device according to claim 1, wherein said pressing switching means is formed integrally with a packaging member for packaging said developing device. 9. An image forming apparatus comprising the developing device according to claim 1. Description: 10. The image forming apparatus, wherein the developing device is detachably mounted on the image forming apparatus, and the moving member is configured such that when the developing device is mounted on the image forming apparatus, the developing device is mounted on the image forming apparatus. The image forming apparatus according to claim 9, wherein the image forming apparatus is pressed more weakly by the seal member than when the image forming apparatus is not mounted on the image forming apparatus.