CN210199514U

CN210199514U - Developing device and image forming apparatus

Info

Publication number: CN210199514U
Application number: CN201921150970.4U
Authority: CN
Inventors: Katsunori Mizuta; 水田克则
Original assignee: Toshiba TEC Corp
Current assignee: Toshiba TEC Corp
Priority date: 2019-07-22
Filing date: 2019-07-22
Publication date: 2020-03-27
Anticipated expiration: 2029-07-22

Abstract

The utility model provides a developing device and image forming device, this developing device include the developer roll, movable mounting be in developer roll one side just is provided with the scraper blade of magnetic sheet, and will the scraper blade press to the elastic component of developer roll still includes: the adjusting piece is arranged between the scraping plate and the developing roller and used for adjusting the distance between the scraping plate and the developing roller; and the driving device is arranged at the end part of the developing roller and is used for controlling the action of the regulating piece along with the reversal of the developing roller. The utility model discloses a regulating part increases the distance between scraper blade and the developer roll to reduce the response magnetic force of magnetic plate on the scraper blade, and then reduce or eliminate the magnetic plate and to the adsorption affinity of the soft developer of adhesion, make it can be easily cleared away, prevented the production of white line or leucorrhea on the image, still prolonged the life of developer roll simultaneously.

Description

Developing device and image forming apparatus

Technical Field

The utility model relates to a can improve the developing device of formation of image effect to and adopt this developing device's image forming apparatus.

Background

In a conventional office, an image forming apparatus (MFP) is generally used as a daily office facility, and the operation of the image forming apparatus is as follows: the method comprises the steps that an original to be transferred is conveyed through an original supply device, a scanning unit obtains an optical analog image signal of the original through exposure, the optical analog image signal is sent to an image forming unit to enable the optical analog image signal to form an electrostatic latent image on the surface of a photosensitive drum, a developing device adsorbs toner onto the photosensitive drum to enable the electrostatic latent image to be changed into a toner image, the toner image is transferred onto paper conveyed by a paper supply device through a transfer belt, finally the toner image on the paper is fixed by a fixing device and then discharged to a paper discharge portion, and therefore the original transfer work is completed.

The existing developing device comprises a developing roller which is contacted with a photosensitive drum and outputs a developer, and accommodating bins which are used for accommodating a toner and a carrier respectively, wherein the two accommodating bins are internally provided with a toner roller and a carrier roller which are used for stirring the toner and the carrier respectively, and one side of the developing roller is provided with a scraper which is used for scraping redundant toner on the developing roller into the accommodating bins.

Continuous transfer of the developing device causes a temperature rise in the body, particularly in a continuous transfer mode at a low transfer rate, and the toner is softened by the high temperature and finally adhered to the blade contacting the developing roller, and the adhered toner reduces the distance between the blade and the developing roller, so that the toner layer at the corresponding position on the developing roller becomes thin or disappears, and a white line or a white band appears on the finally transferred image.

In the prior art, in order to prevent this, the developing device is controlled to rotate reversely before the driving is stopped, and the toner adhered to the back surface of the blade is removed by the toner moving reversely.

SUMMERY OF THE UTILITY MODEL

Specifically, the utility model provides a developing device, including the developer roll, movable mounting is in developer roll one side just is provided with the scraper blade of magnetic sheet, and will the scraper blade press to the elastic component of developer roll still includes: the adjusting piece is arranged between the scraping plate and the developing roller and used for adjusting the distance between the scraping plate and the developing roller; and the driving device is arranged at the end part of the developing roller and is used for controlling the action of the regulating piece along with the reversal of the developing roller.

In another embodiment of the present invention, there is provided an image forming apparatus including: an original document feeding device that conveys an original document to be transferred; a scanning unit that acquires an optical analog image signal of an original; an image forming unit for converting the optical analog image signal into a toner image, including a photosensitive drum carrying an electrostatic latent image converted from the optical analog image signal, and a developing device for converting the electrostatic latent image into a toner image; a transfer device that transfers the toner image onto a sheet; a fixing device that fixes the toner image formed on the sheet and discharges the toner image to a discharge tray; developing device includes the developer roll, movable mounting in developer roll one side just is provided with the scraper blade of magnetic sheet, and will the scraper blade press to the elastic component of developer roll still includes: the adjusting piece is arranged between the scraping plate and the developing roller and used for adjusting the distance between the scraping plate and the developing roller; and the driving device is arranged at the end part of the developing roller and is used for controlling the action of the regulating piece along with the reversal of the developing roller.

The utility model discloses a regulating part increases the distance between scraper blade and the developer roll to reduce the response magnetic force of magnetic plate on the scraper blade, and then reduce or eliminate the magnetic plate and to the adsorption affinity of the soft developer of adhesion, make it can be easily cleared away, prevented the production of white line or leucorrhea on the image, still prolonged the life of developer roll simultaneously.

Drawings

FIG. 1 is a schematic view of an image forming apparatus according to an embodiment of the present invention;

FIG. 2 is a schematic structural view of a developing device according to an embodiment of the present invention;

FIG. 3 is a front view of a developing device according to an embodiment of the present invention;

FIG. 4 is a schematic view showing the influence of the distance between the scraper and the developing roller on the developer conveying amount according to one embodiment of the present invention;

FIG. 5 is a schematic structural view of a developing device mounting adjustment member according to an embodiment of the present invention;

FIG. 6 is a schematic view of the adjustment member of FIG. 5 in an adjusted state;

fig. 7 is a schematic structural diagram of a control device according to an embodiment of the present invention.

Detailed Description

Hereinafter, an image forming apparatus according to an embodiment will be described in detail with reference to the drawings. In the drawings, the same reference numerals are used for the same portions. "above" and "below" refer to the up and down directions when the image forming apparatus shown in fig. 1 is normally placed on the floor. And "left side" and "right side" are the left side and the right side when facing the respective figures.

Fig. 1 is a schematic configuration diagram of an image forming apparatus according to an embodiment of the present invention.

In fig. 1, the image forming apparatus 100 may be an MFP (Multi-function peripherals), a printer, a copier, or the like, which is a multifunction peripheral. In the following description, an MFP is taken as an example.

The MFP100 includes a main body 11 for mounting respective components, an original feeding device 12 for conveying an original to be transferred, and an operation panel 13 for providing various function control keys during image transfer, which are provided on an upper portion of the main body 11, and the operation panel 13 includes an operation portion 14 composed of various keys and a touch panel type display portion 15.

A scanning unit 16 for scanning and reading image information on one side or both sides of the original is provided at a lower portion of the original supply device 12, and the scanning unit 16 reflects the image information on the original irradiated by the light source onto the photoelectric conversion element CCD in the form of a light beam by a mirror group to form an optical analog image signal.

A paper feeding device including a transfer device 17 and a plurality of paper feeding cassettes 18 for storing media of various sizes is also mounted in the main body 11.

The image forming unit includes toner cartridges 28(28Y, 28M, 28C, 28K) that supply respective colors of yellow (Y), magenta (M), cyan (C), black (K), and photosensitive developing portions that generate toner images from the optical analog image signals of the scanner unit 16, the photosensitive developing portions being constituted by the developing devices 20 and the photosensitive drums 22, respectively, wherein 20Y, 20M, 20C, 20K denote photosensitive developing portions that form yellow, magenta, cyan, and black, respectively; an electrostatic latent image is first formed on the photosensitive drum 22 in each photosensitive developing portion, and then the electrostatic latent image is formed into a toner image of a different color by the developing device 20 of the corresponding color, and finally transferred onto the transfer belt 21. Cleaners for cleaning residual toner on the photosensitive developing portions are mounted on the photosensitive developing

portions

20Y, 20M, 20C, and 20K.

The transfer belt 21 is stretched over a driving roller 32 and driven

rollers

33 and 34, and the driving roller 32 is disposed to face a secondary transfer roller 35. When the medium S (sheet) passes between the driving roller 32 and the secondary transfer roller 35, the secondary transfer roller 35 applies a transfer voltage to transfer the toner image on the transfer belt 21 onto the medium S (sheet). A cleaner 36 for cleaning residual toner after transfer of the transfer belt 21 is provided near the driven roller 34 of the transfer belt 21.

Between the sheet feeding device and the secondary transfer roller 35, a separation roller 37 for taking out the medium S (sheet) in the sheet feeding cassette 18 and a conveyance guide 19 for conveying the taken-out sheet and preventing a jam are provided, and a fixing device 39 for fixing a toner image on the medium S (sheet) is provided downstream of the secondary transfer roller 35. A conveyance roller 40 that discharges the medium S (sheet) to a discharge tray 41 is provided downstream of the fixing device 39.

Further, a double-sided conveyance path 42 may be provided downstream of the fixing device 39. The duplex conveying path 42 guides the medium S (paper) in the direction of the secondary transfer roller 35 after reversing the medium S (paper) to perform duplex transfer of the medium S (paper).

In an embodiment of the present invention, as shown in fig. 2, a specific structure of a developing device 20 is disclosed, where the developing device 20 includes a casing 201, a carrier cavity 2011 accommodating a carrier and a toner cavity 2012 accommodating a toner are separated from the casing 201, a carrier roller 202 and a toner roller 203 for stirring are respectively disposed in the carrier cavity 2011 and the toner cavity 2012, a developing roller 204 is disposed at an outlet of the casing 201, a sensor is disposed on one side of the casing 201, the sensor is used for detecting whether a concentration of a developer formed after mixing the carrier and the toner satisfies a requirement, if the concentration is insufficient, the carrier or the toner is automatically added into the toner cavity 2012 (from the toner box 28), and the formulated developer is supplied to the developing roller 204 through the toner cavity 2012.

As shown in fig. 3, a blade 205 is provided on one side of the developing roller 204 in the axial direction, the distance between the blade 205 and the developing roller 204 is adjustable according to the density of the image to be transferred, and the blade 205 scrapes off a set amount of developer back into the toner chamber 2012 when the developing roller 204 rotates. An elastic member 206 that applies an elastic pushing force to the blade 205 is attached to the other side of the blade 205 opposite to the developing roller 204.

A magnetic plate 2051 is attached to one end of the blade 205 close to the developing roller 204, and the magnetic plate 2051 absorbs the magnetic force of the developing roller 204 to become magnetic, thereby attracting a certain amount of the developer 2052 and replenishing the developer 2052 to the developing roller 204 when the developing roller 204 is operated. Since the magnetic property of the magnetic plate 2051 gradually decreases as the distance between the blade 205 and the developing roller 204 increases, the present embodiment mounts the regulating member 207 for regulating the distance between the blade 205 and the developing roller 204 on the developing device 20, and also provides the driving device 208 for controlling the operation of the regulating member 207. The regulating member 207 is independent of the existing regulating structure for regulating the developer concentration on the developing roller 204, and therefore the driving device 208 is activated to drive the regulating member 207 to operate only when the developing device 20 is reversely rotated.

The adjusting member 207 can overcome the elastic force of the elastic member 206 to adjust the scraper 205 to a distance that is not affected by the magnetic force on the developing roller 204, so that the developer 2052 adsorbed or bonded on the magnetic plate 2051 can be easily cleaned when the developing roller 204 rotates reversely after the magnetic force is lost; after the reverse rotation process is completed, the driving device 208 controls the adjusting member 207 to reset the scraping plate 205, and returns to the control of the elastic member 206.

The blade 205 is generally movably fixed to the casing 201 of the developing device 20 through both ends, and therefore, the regulating members 207 may be installed at positions corresponding to the installation points of both ends of the blade 205, respectively. The specific adjusting member 207 may be a structure that directly pushes or pulls the scraping plate 205 toward the elastic member 206 under the control of the driving device 208, such as an elastic rod (not shown) fixed to both ends of the scraping plate 205; there may also be a corresponding pressing structure, such as a wedge (not shown in the figure) installed between the blade 205 and the developing roller 204, and the distance of the blade 205 with respect to the developing roller 204 is controlled by the depth of insertion. The driving device 208 may be a motor of the image forming apparatus 100 or the developing device 20, which drives the adjusting member 207 to operate through a chain or a gear.

Fig. 4 is a graph showing the influence of the distance between the blade 205 and the developing roller 204 on the amount of adsorbed developer, and when the distance between the blade 205 and the developing roller 204 exceeds 0.75mm, the developer conveyance amount linearly increases and then increases in a quadratic curve. This indicates that the magnetic plate 2051 is separated from the developing roller 204 by such a distance that the magnetic force it receives from the developing roller 204 starts to decrease, the attraction force to the developer 2052 decreases, and thus, the developer conveyance amount sharply increases from 0.75mm later. In the present embodiment, according to the principle, the softened regulator 2052 adsorbed on the magnetic plate 2051 is removed by adjusting the distance between the blade 205 and the developing roller 204 by the regulator 207 to be greater than the change point, wherein the adjustment distance between the blade 205 and the developing roller 204 by the regulator 207 is between 0.6 mm and 1.5 mm.

This embodiment increases the distance between scraper blade and the developer roll through the regulating part to reduce the induction magnetic force of magnetic plate on the scraper blade, and then reduce or eliminate the magnetic plate and to the adsorption affinity of the softening developer of adhesion, make it can be easily clear away, prevented the production of white line or white tape on the image, still prolonged the life of developer roll simultaneously.

As shown in fig. 5, in an embodiment of the present invention, the specific adjusting member 207 may be an eccentric 2071 respectively disposed at two ends of the scraper 205 and the developing roller 204, two ends of the developing roller 204 are mounted on the casing 201 through bearings 2041, and the outer circumference of the eccentric 2071 is in contact with the bearings 2041 at two ends of the scraper 205 and the developing roller 204, respectively.

When the developing roller 204 rotates forward, the eccentric 2071 is clamped between the scraper 205 and the bearing 2041 at the position closest to the center of the circle, and the normal distance adjustment of the scraper 205 relative to the developing roller 204 is not affected in this state. As shown in fig. 6, when cleaning is required, the driving device 208 drives the eccentric 2071 to rotate to the position farthest from the center of the circle, and pushes the scraper 205 away from the developing roller 204, so as to reduce or eliminate the magnetic force applied by the developing roller 204 to the magnetic plate 2051, so that the developing roller 204 can easily clean the softened developer 2052 adsorbed on the magnetic plate 2051 when rotating reversely.

The eccentric 2071 may be an asymmetric eccentric structure or an elliptical symmetric shape in radial cross section, and when the developing roller 204 normally operates, the eccentric 2071 contacts the blade 205 and the developing roller 204 with the two opposite surfaces having the shortest diameter, respectively, and when the developing roller 204 rotates reversely, the driving device 208 rotates the eccentric 2071 to contact the blade 205 and the developing roller 204 with the two opposite surfaces having the largest diameter.

As shown in fig. 7, in order to conveniently control the rotation of the eccentric wheel 2071, in an embodiment of the present invention, the specific driving device 208 may include a synchronizing gear 2081 disposed at both ends of the developing roller 204 and rotating synchronously with the developing roller 204, and an adjusting gear 2083 fixedly connected to the two eccentric wheels 2071, respectively, and a one-way gear 2082 connected to the synchronizing gear 2081 and the adjusting gear 2083, wherein the one-way gear 2082 keeps idling when the synchronizing gear 2081 rotates forwards, does not transmit power to the adjusting gear 2083, and only drives the adjusting gear 2083 to rotate when the developing roller 204 rotates backwards.

However, the rotation range of the developing roller 204 in the reverse rotation may be only from the point where the eccentric 2071 is closest to the axis thereof to the point where the eccentric is farthest from the axis thereof.

As shown in fig. 5, when the developing roller 204 rotates forward, the eccentric 2071 remains stationary, and as shown in fig. 6, when the developing roller 204 rotates backward for cleaning, the synchronizing gear 2081 drives the adjusting gear 2083 to rotate through the one-way gear 2082, so that the eccentric 2071 changes from the contact position with the smallest diameter to the contact position with the largest diameter. The diameter of the eccentric 2071 can be determined according to the magnetic influence range of the developing roller 204 on the magnetic plate 2051.

In the present embodiment, the distance between the blade 205 and the developing roller 204 during cleaning is increased by the above structure, so that the magnetic influence of the developing roller 204 on the magnetic plate 2051 on the blade 205 is eliminated or reduced, and the adhered developer 2052 can be removed easily by losing the magnetic attraction.

While several embodiments of the present invention have been described, these embodiments have been presented by way of example only, and are not intended to limit the scope of the invention. These new embodiments can be implemented in other various forms, and various omissions, substitutions, combinations, and changes can be made without departing from the spirit of the present invention. These embodiments and modifications are included in the scope and gist of the present invention, and are included in the present invention described in the claims and the equivalent scope thereof.

Claims

1. The utility model provides a developing device, includes the developer roll, movable mounting just is provided with the scraper blade of magnetic sheet in developer roll one side, and will the scraper blade press to the elastic component of developer roll, its characterized in that still includes:

the adjusting piece is arranged between the scraping plate and the developing roller and used for adjusting the distance between the scraping plate and the developing roller;

and the driving device is arranged at the end part of the developing roller and is used for controlling the action of the regulating piece along with the reversal of the developing roller.

2. The developing device according to claim 1,

the adjusting piece is eccentric wheels which are respectively arranged at two ends of the scraping plate and the developing roller, and the outer circumferences of the eccentric wheels are respectively contacted with the scraping plate and the developing roller.

3. The developing device according to claim 2,

the driving device comprises synchronous gears which are arranged at two ends of the developing roller respectively and rotate synchronously with the developing roller, adjusting gears which are connected with the eccentric wheels respectively, and one-way gears which are connected with the synchronous gears and the adjusting gears, wherein the one-way gears idle when the developing roller rotates forwards and drive the adjusting gears to rotate when the developing roller rotates reversely.

4. The developing device according to claim 2,

the distance between the scraper and the developing roller is adjusted to be 0.6-1.5mm by the adjusting piece.

5. The developing device according to claim 2,

the radial section of the eccentric wheel is an ellipse.

6. An image forming apparatus is characterized by comprising

An original document feeding device that conveys an original document to be transferred;

a scanning unit that acquires an optical analog image signal of an original;

an image forming unit for converting the optical analog image signal into a toner image, including a photosensitive drum carrying an electrostatic latent image converted from the optical analog image signal, and a developing device for converting the electrostatic latent image into a toner image;

a transfer device that transfers the toner image onto a sheet;

a fixing device that fixes the toner image formed on the sheet and discharges the toner image to a discharge tray;

wherein, developing device includes the developer roll, movable mounting in developer roll one side just is provided with the scraper blade of magnetic sheet, and will the scraper blade pressure to the elastic component of developer roll still includes:

7. The image forming apparatus according to claim 6,

8. The image forming apparatus according to claim 7,

9. The image forming apparatus according to claim 7,

10. The image forming apparatus according to claim 7,

the radial section of the eccentric wheel is an ellipse.