JPH04149582A - Development device of image forming device - Google Patents

Abstract

PURPOSE:To easily and uniformly fit a restraining means lengthwise to overall length by providing holding means which are provided on both sides of the restraining means and hold the restraining means and a developer carrier at abutting parts abutting the no-image formation part of the developer carrier at a uniform interval lengthwise to the overall length and elastic means which press the holding means against the developer carrier so that the abutting parts abut on the no-image formation part. CONSTITUTION:When a lower doctor blade 22 is fitted, a pressure spring 24 is incorporated in the recessed part 1b in the flank 11c of a housing 11a while fitted onto the support shaft 23c of a doctor holding member 23, and then the abutting part 23b of the member 23 is pressed against the no-image formation part 12c of a lower magnet roller 12b. Consequently, the edge tip part 22a of the blade 22 and a roller 12b are held at the uniform interval lengthwise to the overall length. Then a stopper 26 is fitted on the front surface of the recessed part 11b to prevent the spring 24 from coming out. Thus, the spring 24 is merely incorporated in the recessed part 11b to fit the blade 22, the fitting operation is greatly reduced, and the productivity and maintainability are improved.

Description

Detailed Description of the Invention [Object of the Invention] (Industrial Application Field) The present invention is an electrophotographic device, etc., in which an electrostatic latent image on a photoreceptor is formed uniformly on a magnetic roller by a magnetic brush. The present invention relates to a developing device in an image forming apparatus that performs development.

(Prior Art) In image forming apparatuses such as copying machines, a magnet roller consisting of a magnet and a cylindrical sleeve surrounding the magnet is generally used to develop an electrostatic latent image formed on a photoreceptor. A magnetic brush developing device is widely used, which rotates a cylindrical sleeve, forms a magnetic brush on its surface, and performs development by sliding this magnetic brush against a photoreceptor.

In this magnetic brush developing device, in order to make the development density uniform, the height of the magnetic brush spikes is uniformly regulated in the longitudinal direction of the cylindrical sleeve. Doctor blades are used to scrape off excess developer on the cylindrical sleeve, which are opposed to each other with a distance of .

In recent years, with the demand for higher performance and higher image quality of image forming apparatuses, the height of the magnetic brush spikes regulated by the doctor blade has tended to be lowered, and the doctor blade attachment has also been reduced. requires high accuracy.

However, in such devices, the doctor blade that regulates the height of the magnetic brush spikes has traditionally been installed by service personnel over the entire length in the longitudinal direction using a leveler with a predetermined thickness, which is an adjustment jig. The doctor blade was attached by screwing it to the part while adjusting the gap between the cylindrical sleeve and the doctor blade.

After the installation is completed, the distance between the cylindrical sleeve and the doctor blade is inspected using a pair of Go/NoGo gauges, which are confirmation jigs and have thicknesses corresponding to the minimum and maximum distances allowed. However, the position adjustment of the doctor blade was completed only after passing this inspection.

For this reason, due to its structure, the doctor blade tends to shift when the screws are tightened when it is fixed, making it difficult to adjust, taking time to install the doctor blade, and requiring skill to achieve high accuracy. However, there was a problem in that workers required a high level of training. Furthermore, there is a problem in that the accuracy varies depending on the operator's habits such as the insertion angle of the leveler. Moreover, since jigs such as levelers and gauges are used, it is necessary to secure a space in the tangential direction to the surface of the cylindrical sleeve for inserting and removing the jigs.

(Problem to be Solved by the Invention) Conventionally, although high precision is required for installing the doctor blade, workers such as service personnel have used jigs such as levelers and gauges to attach the gear 1. This was done by tightening the screws in place while checking the parts. For this reason, it takes time to attach the doctor blade and requires a skilled service person, and there is a problem in that accuracy varies depending on the person, even if the doctor blade is a skilled service person. Furthermore, there is a problem in that a space is required for inserting and removing the jig from the front of the developing device within the developing device.

Therefore, the present invention eliminates the above-mentioned problems, does not require space for inserting and removing the jig, and has a simple structure that allows service personnel to easily and accurately operate the doctor blade regardless of their level of skill. By making it possible to install it,
The purpose is to improve the accuracy of the gap between the cylindrical sleeve and the doctor blade and to improve image quality by making the developed density uniform. Furthermore, it is an object of the present invention to provide a developing device in an image forming apparatus with good productivity and maintainability by shortening the installation time of the doctor blade.

[Structure of the Invention] (Means for Solving the Problems) In order to solve the above problems, the present invention is provided on both sides of the regulating means, and when the regulating means and the developer come into contact with the non-image forming portion of the developer carrier. A holding means having an abutting part that maintains a uniform distance from the carrier over the entire length in the longitudinal direction, and an elastic means that presses the holding means toward the developer carrier so that the abutting part abuts the non-image forming part. It shall be established.

Moreover, in order to solve the above-mentioned problem, the present invention is made of a material that has wear resistance against sliding contact with the non-image forming portion of the developer carrier.

Moreover, in order to solve the above-mentioned problem, the present invention provides the abutting portion with a rotating means that rotates by sliding contact with the developer carrier.

(Function) According to the present invention, the regulating means can be attached by simply pressing the contact portion against the non-image forming portion of the developer carrier using the elastic means without using a jig, and the production thereof can be improved. performance and maintainability are improved. Moreover, the accuracy of the installation of the restriction means is improved, which improves the image quality, and
It is possible to achieve uniform installation accuracy regardless of individual differences among workers.

(Embodiment) An embodiment of the present invention will be described below with reference to FIGS. 1 to 3. FIG. 1 is an explanatory diagram showing a photoreceptor 10 which is an image carrier of an image forming apparatus (not shown) and a developing device 11 provided opposite to a developing position of the photoreceptor 10. As shown in FIG.

An upper magnet roller 12a and a lower magnet roller 12b, which are developer carriers, are provided in the opening of the housing 11a of the developing device full, and toner is supplied into the housing 11a from a toner hopper (not shown). A mixing auger 13 that transports and stirs the toner, and a first and second mixing auger that stirs the developer 14 made of toner and carrier within the housing 11a.
Mixers lea and IBb are provided. The upper and lower magnet rollers 12a and 12b are both composed of a magnet 17 and a non-magnetic cylindrical sleeve 18 made of aluminum that surrounds the magnet I7. By the rotation of the magnetic brushes 20a and 20b, upper and lower magnetic brushes 20a and 20b, which are developer layers, are formed.

In addition, 2I is an upper doctor blade which is fixed to the upper magnetic brush 20b with a screw (not shown) in the same way as in the past in order to regulate the height of the upper magnetic brush 20a, and 22 is an upper doctor blade which is fixed to the lower magnetic brush 20b. This is the lower doctor blade, which is a regulating means for regulating the height of the panicle. A doctor holding member 23, which is a holding means, is attached to both ends of the lower doctor blade 22, and has a side surface 23a in contact with a side surface of the upper doctor blade 21 and a convex contact portion 23b. This doctor holding member 23 is made of polyphenylene sulfide [
PPS] and fluorine [P] to further improve wear resistance.
It is made of an integrally molded resin mixed with Teflon (trade name) powder such as ethylene tetrafluoride.

The contact portion 28b of the doctor holding member 23 is adapted to come into contact with the non-image forming portions 12c on both sides of the lower magnet roller 12b, and its shape is centered around the edge tip 22a of the lower doctor blade 22. It has an arc shape. Further, 24 is a contact portion 2 of the doctor holding member 2B.
3b is the non-image forming portion 12c of the lower magnet roller 12b.
The pressure spring is an elastic means that presses against the doctor holding member 23, and is assembled into the recess 11b formed on the side surface of the casing 11a of the developing device 11 while being fitted onto the support shaft 23e that is protruded on the doctor holding member 23. ing. Note that 2B is the recess 1
This is a stopper that covers the front surface of 1b and prevents the pressure spring 24 from coming off from the recess 11b.

Therefore, when assembling the developing device 11 or attaching the lower doctor blade 22 during maintenance, the operator must hold the housing 11a with the pressure spring 24 fitted to the support shaft 23c of the doctor holding member 23. By incorporating it into the recess 11b of the side surface 11c, the contact portion 23b of the doctor holding member 23 is pressed against the non-image forming portion 12c of the lower magnet roller 12b. This allows the lower doctor blade 2
2 edge tip 22a and lower magnet roller 12b
The gaps are maintained at uniform intervals over the entire length in the longitudinal direction. Note that the direction in which the pressure spring 24 presses the blade holding member 23 toward the lower magnet roller 12b is not perpendicular;
Even if the lower doctor blade 22 is tilted due to some deviation, the contact portion 23b has an arc shape centered on the edge tip 22a of the lower doctor blade 22, so that the contact between the lower doctor blade 22 and the lower magnet roller 12b is maintained. The interval is never changed. And after this, stopper 26
It is attached to the front surface of the concave portion 11b to prevent the pressure spring 24 from coming off, and the attachment of the lower doctor blade 22 is completed.

With this configuration, the operator does not have to screw the doctor blade while measuring the gap over the entire length in the longitudinal direction using a leveler and then perform inspection using a gauge, as in the conventional case, and simply inserts the pressure spring 24 into the recess. The lower doctor blade 22 can be attached by simply incorporating it into the lower doctor blade 11b, and the number of attachment operations is significantly reduced, and productivity and maintenance can be improved by shortening the working time. Moreover, the distance between the lower doctor blade 22 and the lower magnetic roller 12b does not vary due to individual differences in the skill level or habit of the operator, and anyone can operate it with uniformity and high precision without requiring any skill. If the manufacturing precision of the doctor blade 22 and the doctor holding member 23 is uniform, it is easy to achieve uniform development density and the image quality is improved.

It should be noted that the present invention is not limited to the above-mentioned embodiments, and can be modified in various ways. For example, the material of the holding means may be any material that has wear resistance and can slide against the non-image forming portion of the image bearing member. Not limited. The shape of the holding means is also arbitrary, and as in the modified example shown in FIG. The rollers or balls 30 may be rotated by following the rotation of the lower magnetic roller 12b. In this way, the wear of the contact portion 28 can be further reduced, and the life of the contact portion 28 can be extended, and by extension, the life of the doctor blade 22 can be extended.

Note that the shape of the abutting portion can be arbitrary, but if it is made into an arc shape centered on the tip of the edge portion of the regulating means, as in the embodiment, even if the regulating means is slightly tilted, the developer carrier and the regulating means can be The distance between them can always be kept constant, resulting in higher accuracy. Furthermore, the structure of the developing device is also arbitrary; for example, the number of magnetic rollers may be one.

[Effects of the Invention] As described in detail above, according to the present invention, by simply pressing the holding means against the non-image forming portion of the image carrier,
The regulating means can be easily and evenly installed over the entire length in the longitudinal direction. Therefore, there is no need for adjustment jigs like in the past, and there is no need for space for inserting and removing jigs in the developing device, and even non-skilled operators can easily install the regulating means. Attachment is possible. Moreover, compared to the conventional method, the time required to install the regulating means is significantly shortened, and productivity and maintainability are improved. Furthermore, unlike in the past, even experienced workers do not have variations in accuracy due to individual differences, and the gap between the developer carrier and the regulating means can be maintained uniformly with high precision. Image quality can be improved by making the image density uniform.

[Brief explanation of drawings]

1 to 3 show an embodiment of the present invention.
b) is a schematic explanatory diagram of the photoreceptor and developing device viewed from the side;
Figure 1 (B) is a partially enlarged view of Figure 1 (A).
The figure is a schematic explanatory view of the lower magnet roller and the lower doctor blade viewed from the longitudinal direction, and FIG. 3 is a schematic explanatory view of a developing device showing another example of the present invention. 10...Photoreceptor, ]]...Developing device, 1
2b...Lower magnet roller, 22...Lower doctor blade, 23...Doctor holding member, 24...Pressure spring, Agent: Patent Attorney Norio Ogo Figure

Claims (3)

[Claims] (1) In a developing device that develops an electrostatic latent image on an image carrier with a developer layer formed on a developer carrier and whose height is uniformly regulated by regulating means, the regulating means is provided on both sides of the Due to the contact of the developer carrier with the non-image forming area,
holding means having an abutment portion that maintains a uniform distance between the regulating means and the developer carrier over the entire length in the longitudinal direction;
A developing device for an image forming apparatus, comprising elastic means for pressing the holding means toward the developer carrier so that the abutting portion comes into contact with the non-image forming portion. (2) Development in the image forming apparatus according to claim 1, wherein the contact portion is made of a material that is resistant to wear against sliding contact with the non-image forming portion of the developer carrier. Device. (3) Claim 1, characterized in that the contact portion is provided with a rotating means that rotates by sliding contact with the developer carrier.
2. A developing device in an image forming apparatus according to any one of Items 1 and 2.