JPH0579564U - Image forming device - Google Patents

Abstract

(57) [Abstract] [Purpose] Brush charging that can reliably remove adhering substances such as toner on brush bristles without scattering with simple operation, and can uniformly and stably charge the image bearing member surface to a desired potential. Provide a vessel. [Structure] The brush charger 2 is formed by implanting conductive brush bristles 2a on a substrate 2d, and the brush bristles 2a are installed so that the tips of the brush bristles 2a are in sliding contact along the width direction of the peripheral surface of the photosensitive drum 1. A handle portion 2d1 is formed by extending one end of a substrate 2d of the brush charger 2 and the handle portion 2d1 is projected from the side frame 6 to the outside. A recycle pipe 5 is arranged between the photoconductor drum 1 and the side frame 6, and a toner receiving portion 5 a is projectingly provided from the recycle pipe 5 toward the brush charger 2. The wall 5a2 of the toner receiving portion 5 on the side of the side frame 6 is projected into the insertion / removal path C of the brush charger 2 so that the brush deposit is knocked off during the insertion / removal operation.

Description

[Detailed description of the device]

[0001]

[Technical field of invention]

 The present invention relates to an image forming apparatus using a brush charger as a means for uniformly charging the surface of an image carrier to a predetermined potential.

[0002]

[Prior art and its problems]

 In recent years, a corona discharge type charging device has been widely used as a charging means for uniformly charging the surface of an image bearing member to a predetermined potential in an image forming apparatus such as a printer. However, this corona discharge type charging device has an environmental problem that ozone generated during corona discharge pollutes not only the equipment atmosphere but also the atmosphere. Therefore, attention is paid to the conventionally used flat type fixed-type brush charger 50 as shown in FIG.

In FIG. 5, a brush charger 50 in which conductive brush bristles 52 are planted on the lower surface of a substrate 51 made of a conductive long material is arranged such that its longitudinal direction is in the width direction of the peripheral surface of the photosensitive drum 53. The ends of the conductive brush bristles 52 are extended and brought into contact with the peripheral surface of the photosensitive drum 53. To uniformly charge the peripheral surface of the photosensitive drum 53, a predetermined voltage is applied to the brush bristles 52 through the substrate 51. This type of brush charger, such as the brush charger 50, has the advantages that the generation of ozone is extremely small, the power supply voltage can be kept relatively low, and the structure is simple.

However, in the case of the above-mentioned fixed contact type brush charger, the small size developer particles such as toner and external additives which are not removed by the cleaning means are captured by the brush bristles 52, but the bristles 52 Remains in contact with the peripheral surface of the photoconductor drum 53, so that it adheres to the brush bristles 52 as it is. The deposits on the brush bristles 52 gradually increase as the image formation is repeated. As a result, the charging performance of the brush charger 50 deteriorates and the surface of the image carrier cannot be uniformly charged at a desired potential.

[0007] Therefore, a detachable brush charger has been proposed in which the brush charger is detachably installed in the main body of the image forming apparatus, and is detached at an appropriate interval to clean the brush bristles with a vacuum cleaner or the like. ing. With this method, cleaning work is troublesome, maintenance operability is significantly reduced, and the commercial value of the image forming apparatus is reduced. In order to improve the operability of cleaning work, a method has been proposed in which brush bristles are rubbed against a striking member provided in the main body of the image forming apparatus when the brush charger is inserted and removed. There is a problem in that the adhered hair is scattered inside the image forming apparatus to contaminate the inside of the apparatus.

[0006]

[The purpose of the device]

 The present invention has been made in view of the above-mentioned problems of the prior art, and it is possible to reliably remove adhering substances such as toner on brush bristles without scattering by a simple operation, and to obtain a desired surface of an image carrier. An object of the present invention is to provide a brush charger that can be uniformly and stably charged with a potential.

[0007]

[Key points of the device]

 In order to achieve the above-mentioned object, the main point of the present invention is to provide an image carrier that is circulatively movable and a large number of conductive brush bristles, and the brush bristle tips are substantially orthogonal to the moving direction on the surface of the image carrier. In the image forming apparatus, there is provided a brush charger which is slidably supported along a direction in which the electrostatic latent image formed on the surface of the image carrier is developed into a toner image. A charger is provided so as to be movable in the orthogonal direction until at least the entire charger can be retracted from the surface of the image carrier, and the charger contacts the brush bristles and adheres to the bristles during the movement of the brush charger. The point is to have an adhering matter collecting means for separating the kimono and collecting it in the image display device.

[0008]

[Example of device]

 The present invention will be described in detail below with reference to the embodiments shown in FIGS. FIG. 1 is a schematic cross-sectional view showing the configuration of an image forming process unit in an optical writing printer as an embodiment of the present invention. In the figure, a photosensitive drum 1 serving as an image carrier is provided so as to be rotatable in the direction of arrow a. A brush charger 2 is provided around the photosensitive drum 1, just above the photosensitive drum 1 in this example. The brush charger 2 is installed so that it can be inserted and removed in a direction perpendicular to the paper surface. The configuration of the brush charger 2 will be described later in detail.

A developing device 3 is arranged downstream of the brush charger 2 in the rotation direction of the photosensitive drum 1. In this example, a non-magnetic one-component developing system is adopted, and a non-magnetic toner t is put in the developer storage chamber 3a of the developing device 3. A toner supply port Of is formed in a portion of the developing device 3 facing the peripheral surface of the photosensitive drum 1, and a developing sleeve 3b is rotatably disposed in the toner supply port Of. The developing sleeve 3b is supported such that its peripheral surface is in close proximity to the peripheral surface of the photosensitive drum 1 with a minute gap. The toner supply roll 3c is juxtaposed to the developing sleeve 3b so that both peripheral surfaces of the toner supply roll 3c can slide in contact while moving in opposite directions. The toner supply roll 3c holds the non-magnetic toner t at the sliding contact portion with the peripheral surface of the developing sleeve 3b and forcibly carries it on the peripheral surface of the developing sleeve 3b. A toner layer thickness regulating member 3d is brought into contact with the peripheral surface of the developing sleeve 3b on the downstream side of the toner supply roll 3c. The toner layer thickness regulating member 3d regulates the layer thickness of the toner layer carried on the peripheral surface of the developing sleeve 3b. The toner thinned by the toner layer thickness regulating member 3d is conveyed to the developing position close to the peripheral surface of the photosensitive drum 1 as the developing sleeve 3b rotates, and is formed on the peripheral surface of the photosensitive drum 1 here. Is supplied to the electrostatic latent image and is developed. An optical writing head (not shown) is provided between the brush charging device 2 and the developing device 3.

A cleaner 4 is provided near the peripheral surface of the photosensitive drum 1 and on the opposite side of the developing device 3. The cleaner 4 removes the untransferred toner remaining on the peripheral surface of the photosensitive drum 1 without being transferred onto the paper at the transfer portion on the downstream side of the developing device 3. The cleaner 4 of this example is a blade type cleaner, and includes a cleaning blade 4a. The cleaning blade 4a is supported so that its tip comes into contact with the peripheral surface of the photosensitive drum 1 from the counter direction. The untransferred toner scraped off from the peripheral surface of the photosensitive drum 1 by the cleaning blade 4a drops to the bottom of the toner recovery chamber 4b of the cleaner 4.

A toner recycling mechanism Rt is provided between the cleaner 4 and the developing device 3. The toner recycling mechanism Rt includes a toner discharge roll 4c laid at the bottom of the toner recovery chamber 4b of the cleaner 4, a toner carry-in roll 3e laid at the bottom of the toner storage chamber 3a of the developing device 3, and a cleaner 4 and the developing device 3. It consists of a recycling pipe 5 installed in the. The recycle pipe 5 connects a carry-out pipe (not shown) projecting from the side of the cleaner 4 and a carry-in pipe (not shown) projecting from the side of the imager 3 in a communicating manner. Has a transport roll (not shown). The untransferred toner scraped off by the cleaning blade 4a is carried out of the cleaner by the carry-out roll 4c and then carried by the recycle pipe 5 to the carry-in pipe on the side of the developing device 3, and is carried by the carry-in roll 3e to the bottom of the storage toner t. Is brought in. At this time, the carry-in roll 3e carries in the collected toner conveyed to the bottom of the existing toner t while stirring the collected toner.

Thus, a toner receiving portion 5a as a brush deposit collecting means is provided in a protruding manner at a portion of the recycling pipe 5 located below the front end portion with respect to the withdrawal direction of the brush charger 2. .. As shown in FIG. 2, the toner receiving portion 5a is formed in a rectangular tube shape, and its inner width Wr is set to be substantially the same as the width Wb of the brush bristle portion 2a of the brush charger 2 shown in FIG. There is. Of the four side walls forming the toner receiving portion 5a, only the upper end of the inner side wall 5a1 (on the side of the photosensitive drum) is cut out. The notch depth d in this case is preferably approximately the same as the length of the brush bristles.

The configuration of the brush charger 2 of this example will be described with reference to FIG. As shown in the schematic view of FIG. 3, a large number of conductive rayon fibers 2a1 are uniformly woven into the base cloth 2b so that both ends thereof stand up as brush hairs 2a. This is fixed to the surface of the substrate 2d made of a conductive plate material via the back coat layer 2c made of a conductive material.

As shown in FIG. 4, the brush charger 2 configured as described above is installed in a removable manner. FIG. 4 is a sectional view taken along line IV-IV in FIG. In the figure, one end side (on the side where the recycling pipe 5 is disposed) of the substrate 2d of the brush charger 2 is extended and the tip portion thereof is bent to form a grip portion 2d1. The tip of the handle portion 2d1 is projected to the outside from the side frame 6 of the machine body. A recycling pipe 5 is arranged between the photosensitive drum 1 and the side frame 6. The height of the toner receiving portion 5a protruding from the recycle pipe 5 is set so that the tip of the toner receiving portion 5a projects into the insertion / removal path C of the brush charger 2. As a result, adhered matter such as toner particles adhered to the brush bristles can be knocked off into the recycling pipe 5 as described below.

At the time when an image failure occurs due to charging failure such as black stripes or the like on a regular basis, the operator opens the machine, holds the grip portion 2d1, and holds the brush charger 2 several times in the direction of arrow b. Remove and insert. As a result, at least the tip of the brush bristles 2a is brought into sliding contact with the tip of the wall 5a2 of the toner receiving portion 5a on the side of the side frame 6, and the adhering matter of the brush bristles 2a is received and knocked down into the recycling pipe 5 from the port Or. At this time, when the wall 5a1 on the side of the photosensitive drum 1 in the toner receiving portion 5a and the brush bristles 2a come into contact with each other, the adhering matter is knocked off the outside of the receiving port Or and scatters to contaminate the inside of the machine. However, in the toner receiving portion 5a of this example, since the tip portion of the wall 5a1 on the photoconductor drum 1 side is cut out by an appropriate amount, the tip portion of the brush bristles 2a does not come into contact with this wall 5a1 and scatters the brush deposits. Is prevented. By such a simple operation, the adhering matter on the brush bristles 2a can be almost collected and removed without scattering, and the desired charging performance can be stably exhibited without contaminating the inside of the machine. As a result, the peripheral surface of the photosensitive drum 1 can be uniformly and stably charged to a predetermined potential for a long period of time.

Further, the brush deposits that have been knocked off into the recycle tube 5 are returned to the developing device together with the untransferred toner collected by the cleaner by the transport roll 5b. In this case, most of the deposits on the brush are toner particles that could not be removed by the cleaner and developer particles such as small external additives, so even if they are returned to the developing unit together with the untransferred toner collected by the cleaner. There is no hindrance and the developer particles can be reused to a higher degree.

It should be noted that the present invention should not be limited to the preferred embodiments described above, and various modifications can of course be made within the technical scope of the present invention. For example, in the above-described embodiment, the receiving port Or of the toner receiving portion 5a is always open, but a lid is provided on the receiving port Or, and the lid is rotated in accordance with the inserting / removing operation of the brush charger to open / close the receiving port 5a1. It can also be configured to do so. In this case, an opening projection may be provided on the handle portion of the brush charger, and the lid may be rotated and opened by engaging with a part of the lid. Further, the present invention can be applied to an image forming apparatus without a cleaner. In that case, it is necessary to independently provide an adhering material conveying means between the brush adhering material collecting means and the developing device. Further, the present invention can be applied to an image forming apparatus having a cleaner but not provided with a recycling mechanism, and in that case, a similar adhering material conveying means may be provided. In addition, the present invention can be effectively applied not only to the case where the image carrier is the photosensitive drum as in the above-described embodiment, but also to the case where the image carrier is an endless belt-shaped dielectric belt having a surface coated with a dielectric. it can.

[0018]

[Effect of the device]

 As described above in detail, according to the present invention, the brush charger is provided so as to be movable in the direction orthogonal to the moving direction of the image carrier until at least the entire brush charger can be retracted from the surface of the image carrier. While the brush charger is in contact with the brush bristles, the adhering substances are separated from the brush bristles and collected in the developing device to easily remove the adhering substances such as developer particles from the brush bristles. It can be collected and recycled without being scattered. As a result, the surface of the image bearing member can be stably and uniformly charged to a predetermined potential by the brush charger for a long period of time by performing a simple maintenance work, and a good image without image defects due to poor charging can be obtained. It is possible to provide an image forming apparatus with excellent operability that can be stably obtained. In addition, the inside of the machine is not contaminated by the deposits detached from the brush bristles, and the developer particles can be highly reused.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view showing an image forming process unit in an optical writing printer as an embodiment of the present invention.

FIG. 2 is a perspective view showing a toner receiving unit of the image forming process unit.

FIG. 3 is a schematic diagram showing a configuration of a brush charger in the image forming process.

FIG. 4 is a schematic diagram of the brush charger shown in FIG.
FIG. 4 is a sectional view taken along line IV-IV.

FIG. 5 is a perspective view showing a mounted state of a conventional brush charger.

[Explanation of symbols]

 1,53 Photosensitive drum 2,50 Brush charger 2a, 52 Brush bristles 2d, 51 Substrate 2d1 Handle 3 Developer 3e Carry-in roll 4 Cleaner 4c Carry-out roll 5 Recycle pipe 5a Toner receiving part 6 Side frame Or receiving port

Claims (2)

[Scope of utility model registration request] 1. An image carrier provided so as to be circulatively movable, and a large number of conductive brush bristles, and the tip of the brush bristles can slidably contact the surface of the image carrier along a direction substantially orthogonal to the moving direction. An image forming apparatus having a brush charger formed by supporting a brush charger and a developing device for developing an electrostatic latent image formed on the surface of the image carrier into a toner image. It is provided so as to be movable in the orthogonal direction until it can be retracted from the surface of the carrier, and during the movement of the brush charger, the adhering substances that come into contact with the brush bristles and adhere to the brush bristles are separated and collected in the developing device. An image forming apparatus, comprising: an adhering matter collecting unit. 2. The adhering matter collecting means is provided with a receiving port provided in a recycling conveying path for returning the toner collected from the surface of the image bearing member to the developing device, and a receiving port which comes into contact with the brush bristles. The image forming apparatus according to claim 1, further comprising: a wall surface that scrapes off the attached matter in the recycling conveyance path.