JP2010026101A - Developing device, process cartridge, and image forming device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a developing doctor capable of preventing the deterioration of toner by guiding the developer to a DG part and reducing the pressure loss for the toner. <P>SOLUTION: The developing doctor includes: a developing roller for retaining developer; a developing doctor for regulating the layer thickness of the developer retained on the surface of the developing roller; and a rotating conveyance unit for feeding the developer on the surface of the developing roller. The developing doctor contacts a communication path which is a path where the developer is conveyed from the rotating conveyance unit to the developing roller, and has a convex portion for guiding the developer to a doctor gap. The convex portion is composed so as to make an obtuse angle by the communication path and the planar section not to interfere with the flow of the developer from the communication path. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a developing device, a process cartridge, and an image forming apparatus having a developing doctor that regulates the layer thickness of a developer held on the surface of a developing roller.

  First, the basic configuration of the printer will be described. FIG. 5 is a schematic configuration diagram of the printer. The image forming unit will be described as a process cartridge.

  The printer 100 includes four process cartridges 6Y, 6M, 6C, and 6K for generating toner images of yellow, magenta, cyan, and black (hereinafter, Y, M, C, and K). The process cartridges use different color toners as image forming substances, but they have the same configuration except for the color of the toner, and can be attached to and detached from the printer 100 body. It can be done.

  Below the process cartridges 6Y, 6M, 6C, and 6K, an exposure device 7 serving as a latent image forming unit is provided. The exposure device 7 performs exposure by irradiating the photosensitive members 1Y, 1M, 1C, and 1K of the process cartridges 6Y, 6M, 6C, and 6K with the laser light L emitted based on the image information. An electrostatic latent image for C and K is formed.

  The exposure device 7 irradiates the photosensitive member through a plurality of optical lenses and mirrors while scanning a laser beam L emitted from a light source with a polygon mirror rotated by a motor.

  On the lower side of the exposure apparatus 7 in the figure, a paper supply unit having a paper storage cassette 26, a paper supply roller 27, and a registration roller pair 28 is provided.

  In the paper storage cassette 26, a plurality of transfer papers P, which are recording bodies, are stacked and stored. A paper feed roller 27 is in contact with the uppermost transfer paper P, and the paper feed roller 27 is driven by driving means (not shown). When rotated counterclockwise in the figure, the transfer paper P is fed one by one from the top toward the roller of the registration roller pair 28.

  The registration roller pair 28 functions as a pair of timing rollers, and both the rollers are driven to rotate so that the transfer paper P is fed out, but the rotation is temporarily stopped immediately after the transfer paper P is sandwiched, and the transfer paper P is stopped at an appropriate timing later. To the secondary transfer nip.

  Further, an intermediate transfer unit 15 is provided above the process cartridges 6Y, 6M, 6C, and 6K in the drawing. The intermediate transfer unit 15 is stretched by a secondary transfer backup roller 12, a cleaning backup roller 13, and a tension roller 14 that are electrically grounded to an endless intermediate transfer belt 8 that is an intermediate transfer member. By rotating the one roller, it moves endlessly counterclockwise in the figure. The intermediate transfer unit 15 is also provided with four primary transfer bias rollers 9Y, 9M, 9C, and 9K, and a cleaning device 10.

  The primary transfer bias rollers 9Y, 9M, 9C, and 9K sandwich the intermediate transfer belt 8 that moves endlessly between the photoreceptors 1Y, 1M, 1C, and 1K to form a primary transfer nip. In these methods, a transfer bias having a polarity opposite to that of toner (for example, plus) is applied to the back surface (loop inner peripheral surface) of the intermediate transfer belt 8.

  The intermediate transfer belt 8 sequentially passes through the primary transfer nips for Y, M, C, and K while moving endlessly, and Y, M, C, and K on the photoreceptors 1Y, 1M, 1C, and 1K. The toner images are overlaid and primarily transferred. As a result, a toner image (hereinafter, a four-color toner image) in which the four colors are superimposed on the intermediate transfer belt 8 is formed.

  The secondary transfer backup roller 12 sandwiches the intermediate transfer belt 8 between the secondary transfer roller 19 and forms a secondary transfer nip. The four-color toner image formed on the intermediate transfer belt 8 in the above process is transferred onto the transfer paper P at the secondary transfer nip.

  The cleaning device 10 cleans the transfer residual toner that is not transferred to the transfer paper P but remains attached to the intermediate transfer belt 8 after passing through the secondary transfer nip.

  A fixing device 20 is provided in the conveyance direction of the transfer paper P sent out from the secondary transfer nip. The fixing device 20 fixes the four-color toner image transferred to the surface by heat and pressure when passing between the rollers.

  The transfer paper P on which the four-color toner image is fixed is discharged outside the apparatus through a pair of paper discharge roller pairs 29.

  A stack unit 30 is formed on the upper surface of the printer main body 100, and the transfer sheets P discharged to the outside by the discharge roller pair 29 are sequentially stacked on the stack unit 30. A bottle container 31 is provided below the stack unit 30 to store toner bottles 32Y, 32M, 32C, and 32K of the respective colors.

  Next, an explanation will be given for generating a toner image using the process cartridge 6Y as an example. FIG. 6 is a detailed configuration diagram of a conventional process cartridge 6Y. The process cartridge 6Y includes a drum-shaped photoconductor 1Y, a drum cleaning device 2Y, a charge eliminating device (not shown), a charging device 4Y, and a developing device 5Y.

  The charging device 4Y uniformly charges the surface of the photoreceptor 1Y that rotates in the direction of the arrow by a driving unit (not shown). The uniformly charged surface of the photoreceptor 1 </ b> Y is exposed and scanned by the laser beam L to carry an electrostatic latent image for Y. The developing device 5 </ b> Y using Y toner develops the electrostatic latent image into a Y toner image and performs intermediate transfer onto the intermediate transfer belt 8.

  The drum cleaning device 2Y removes the toner remaining on the surface of the photoreceptor 1Y after the intermediate transfer process, and the charge eliminating device removes the residual charge of the photoreceptor 1Y after the cleaning. The surface of the photoreceptor 1 </ b> Y is initialized by the charge removal by the charge removal device, and prepared for the next image formation.

  Similarly, the other process cartridges 6M, 6C, and 6K form M, C, and K toner images on the photoreceptors 1M, 1C, and 1K, respectively, and are intermediately transferred onto the intermediate transfer belt 8.

  Next, the developing device 5Y provided in the process cartridge 6Y will be described in detail. The developing device 5Y includes a magnetic field generating means inside, a developing roller 51Y as a developer carrying member that carries and conveys a two-component developer containing magnetic particles and toner, and is carried on the developing roller 51Y. And a developing doctor 52Y as a developer regulating member for regulating the layer thickness of the conveyed developer.

  Here, the place where the developing roller 51Y is accommodated is the first room 53Y, and the place where the developer is accommodated is the second room 54Y. The second chamber 54Y includes a toner conveying screw (conveying body) 55Y for agitating and conveying the toner. Further, the developing device 5Y is largely formed by a first member 75Y (upper case) including the inner wall of the first chamber 53Y and a second member 76Y (lower case) including the inner wall of the second chamber 54Y.

  Around the developing doctor 52Y, a magnetic plate 80Y is provided on the developing roller 51Y side, and a doctor seal member 81Y is provided between the doctor 52Y and the second member 76Y (lower case).

  Note that SUS304-No.2B is used as the material of the developing doctor 52Y, and SUS430-No.2B is used as the material of the magnetic plate 80Y.

  The toner conveyance screw (conveyance body) 55Y includes a first conveyance screw 55Ya and a second conveyance screw 55Yb, and includes a toner supply port 58Y for taking the developer into the second chamber 54Y, and the first chamber 53Y. And a communication port 59Y.

  Above the toner supply port 58Y, a shutter 71Y for closing the toner supply port 58Y and a toner supply port case 72Y that holds the shutter 71Y and is provided so as to cover the toner supply port 58Y are provided.

  A density detection sensor 56Y that detects the toner density of the developer is provided below the toner conveying screw 55Y. When the density detection sensor 56Y detects that the toner density in the second chamber 54Y is insufficient, the drive motor 41Y is rotated by the supply signal from the control unit 57Y, and the toner bottle 32Y is rotated to supply the toner.

  Among the printers described above, in recent years, a printer with higher speed has been desired in order to improve productivity. However, since the temperature inside the developing device is expected to rise with this, it is necessary to suppress the temperature rise near the image forming unit.

  Therefore, for example, in the invention described in Patent Document 1, in order to suppress the frictional heat generated between the developing roller and the toner regulating member, the developing doctor and the heat dissipating heat sink for equalizing the internal temperature are formed by the same member. By adopting an integrated structure, temperature rise in the device is suppressed.

  On the other hand, the developing doctor used conventionally has a shape obtained by bending a SUS blade into an L shape.

FIG. 7 is a view showing the flow of the developer in the conventional process cartridge. An arrow A in the figure indicates the flow direction of the developer.
JP 2006-301330 A

  However, although the invention in Patent Document 1 can suppress toner fixation due to heat generation, it has a problem that it is not suitable for downsizing the apparatus because the developing doctor and the heat sink are integrated.

  Further, in the conventional developing doctor, since the path for guiding the developer to the layer thickness regulating portion (gap between the developing roller and the developing doctor = doctor gap (DG)) is a right angle, the developer stays in that portion. It cannot be guided smoothly.

  That is, as shown in FIG. 7, the developer is guided from the toner conveying screw 55Y to the DG portion through the communication port 59Y, but the shape of the second member 76Y (lower case) in front of the developing doctor 52Y (in the drawing) Since part B) is flat, the developer flow is not smooth, and the developer stays and is stressed, which may cause deterioration.

  The arrow C indicates the direction of the force received by the developing doctor 52Y from the doctor seal member 81Y. Since the developing doctor 52Y is flat in the direction of the arrow C, the direction of the developing doctor 52Y is weak against deformation. .

  Conventionally, such a problem has been dealt with by using a lower case in which the shape of the portion is formed obliquely or by providing another member, but in order to smoothly guide the developer to the DG portion, It is difficult to freely manufacture a lower case having a desired oblique angle in the portion, and it is expensive to provide another member.

  Accordingly, the present invention has been made in view of the above problems, and an object thereof is to provide a developing doctor that smoothly guides a developer to the DG portion, reduces pressure loss to the developer, and prevents deterioration. To do.

  In order to solve the above-described problems, a developing device according to the present invention includes a developing roller for holding a developer, a developing doctor for regulating the layer thickness of the developer held on the surface of the developing roller, and supplying the developer to the surface of the developing roller The developing doctor is in contact with a communication port which is a path from the developer conveying carrier to the developing roller, and has a convex part for guiding the developer to the doctor gap. The obtuse angle is formed between the communication port and the flat portion so as not to obstruct the flow of the developer from the communication port.

  The developing doctor is made of aluminum.

  The developing doctor includes a magnetic member on a surface for guiding the developer.

  The developing doctor is characterized in that a seal member is provided on a surface of the convex portion that faces the surface that guides the developer.

  The developing doctor has one or more plate-like convex portions on a flat portion that does not guide the developer.

  A process cartridge according to the present invention includes any one of the developing devices described above.

  In addition, an image forming apparatus according to the present invention includes any one of the developing devices described above or the process cartridge described above.

  According to the present invention, a shape for smoothly guiding the developer to the DG portion can be easily produced, pressure loss to the developer can be reduced, and deterioration can be prevented.

  FIG. 1 is a cross-sectional view of a process cartridge having a developing doctor in an embodiment of the present invention.

  The development doctor 90Y has a convex part for guiding the developer to the DG part. The lower side in the vertical direction of the projection is horizontal and is provided with a doctor seal member 81Y.

  The convex portion is in contact with the communication port 59Y. The communication port 59Y and the convex portion are configured to form an obtuse angle, and guide the developer to the DG portion. Furthermore, the angle between the convex portion and the flat portion where the developer flows has an angle of 90 degrees or more with respect to the flow so that the flow is not hindered and retained.

  With the development doctor according to the present embodiment, it is possible to easily produce an inclination angle for accurately guiding the developer to the DG portion, and to make the flow of the developer smooth. It is possible to reduce pressure loss and prevent deterioration.

  Moreover, the shape can be formed more easily by using aluminum as the material of the developing doctor. That is, by using aluminum, extrusion processing is possible, and processing can be performed with high accuracy. In addition, the cost can be reduced and the weight can be reduced.

  An arrow C in the figure is the direction of the force that the developing doctor 90Y receives from the doctor seal member 81Y, and at the same time, the developing doctor 90Y is deformed.

  The developing doctor 90Y in the present embodiment has an inclination for guiding the developer to the DG portion, and has a thickness in the direction of the arrow C of the convex portion, and thus has a strong shape resistant to deformation. Therefore, the deformation of the developing doctor 90Y can be minimized.

  2 and 3 are views showing a magnetic plate attachment position to the developing doctor in the embodiment of the present invention.

  FIG. 2 shows an example in which the magnetic plate 80Y is attached to the flat portion on the upstream side in the developer flow direction of the developing doctor 90Y. FIG. 3 shows an example in which the magnetic plate 80Y is attached to the convex portion on the developer flow side of the developing doctor 90Y.

  As shown in this embodiment, by providing the developing doctor 90Y with the magnetic plate 80Y, the developer can be effectively spiked and the thin layer can be easily made uniform.

  FIG. 4 is a cross-sectional view of a process cartridge having a developing doctor in another embodiment of the present invention.

  The developing doctor 91Y has a convex portion for guiding the developer to the DG portion, similarly to the above configuration. Further, the convex portion is in contact with the communication port 59Y, and the communication port 59Y and the convex portion are configured to form an obtuse angle, guide the developer to the DG portion, and the convex portion of the portion where the developer flows. And the flat portion have an angle of 90 degrees or more with respect to the flow so that the flow is not hindered and retained. Furthermore, it has one or more L-shapes on the side where the developer does not flow.

  The L-shaped part has a shape in which one end on the side where the developer does not flow is bent. Moreover, you may have a some plate-shaped convex part between this L-shaped part and the convex part for guide | inducing a developing agent to DG part.

  By providing such an L-shaped portion and a plate-like convex portion, the strength of the developing doctor can be increased, the surface area can be increased, and the developer can be efficiently cooled by the fin effect.

  In the present embodiment, the process cartridge has been described. However, the same invention can be implemented with a single developing device. Of course, the present invention can also be applied to a developing device and an image forming apparatus using a process cartridge.

  The present invention has been described above by the preferred embodiments of the present invention. While the invention has been described with reference to specific embodiments thereof, various modifications and changes can be made to these embodiments without departing from the broader spirit and scope of the invention as defined in the claims. is there.

It is a block diagram of the process cartridge which concerns on embodiment of this invention. It is a block diagram of the process cartridge which concerns on other embodiment of this invention. It is a block diagram of the process cartridge which concerns on other embodiment of this invention. It is a block diagram of the process cartridge which concerns on other embodiment of this invention. It is a block diagram concerning the conventional image forming apparatus. It is a block diagram concerning the conventional process cartridge. It is a figure which shows the flow of the developer which concerns on the conventional process cartridge.

Explanation of symbols

1Y, 1M, 1C, 1K photoconductor 2Y, 2M, 2C, 2K drum cleaning device 4Y, 4M, 4C, 4K charging device 5Y, 5M, 5C, 5K developing device 6Y, 6M, 6C, 6K process cartridge 51Y, 51M, 51C, 51K Developing roller 52Y, 52M, 52C, 52K Developing doctor 80Y, 80M, 80C, 80K Magnetic plate 81Y, 81M, 81C, 81K Doctor seal member 100 Printer

Claims (7)

A developing roller for holding the developer;
A developing doctor for regulating the layer thickness of the developer held on the surface of the developing roller;
A rotating carrier for supplying a developer to the surface of the developing roller,
The developer doctor has a convex portion for contacting the developer to the doctor gap, in contact with a communication port that is a path of the developer from the rotating conveyance body to the developing roller,
The developing device according to claim 1, wherein the convex portion forms an obtuse angle with the communication port and the flat portion so as not to hinder the flow of the developer from the communication port.   The developing device according to claim 1, wherein the developing doctor is aluminum.   The developing device according to claim 1, wherein the developing doctor includes a magnetic member on a surface for guiding the developer.   4. The developing device according to claim 1, wherein the developing doctor includes a seal member on a surface of the convex portion that faces the surface that guides the developer. 5.   5. The developing device according to claim 1, wherein the developing doctor has one or more plate-like convex portions on a flat portion that does not guide the developer. 6.   A process cartridge comprising the developing device according to claim 1.   An image forming apparatus comprising the developing device according to claim 1 or the process cartridge according to claim 6.

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