JP2001255739A - Developing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the change in a layer thickness regulating gap while suppressing the increase in the manufacturing cost of a developing device. SOLUTION: This developing device is provided with a layer thickness regulating member 3 arranged opposed to the surface of a developing roll Ga in a layer thickness adjusting area which is a part on the upstream side of developing areas Q2y(Q2m, Q2c and Q2k) along the surface of the rotating and moving developing roll Ga and a container member V1 having high rigidity with which a part of a developing container V is constituted and that is formed of a material whose rigidity is higher than that of the material of the other part of the developing container V and is provided with the layer thickness regulating member 3 on its inside surface.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for forming an electrostatic latent image on the surface of an image bearing member, and transporting a developer layer formed on the surface of a developing roll to a developing area opposed to the surface of the image bearing member, and The present invention relates to a developing device used in an electrophotographic image forming apparatus that develops an electrostatic latent image into a toner image.

[0002]

2. Description of the Related Art The developing device has a developing container for accommodating a developer and rotatably supporting a developing roll.
The developing roll conveys the developer adhered to the surface of the developing roll to a development area facing the surface of the image carrier in order to develop the electrostatic latent image formed on the surface of the image carrier into a toner image. In order to transport the developer layer on the developing roll surface to an appropriate layer thickness with an appropriate thickness, the layer is regulated by a layer thickness regulating member at an upstream portion (layer thickness adjusting region) of the developing region along the rotating developing roller surface. The thickness of the developer layer is adjusted.

[0003]

The thickness of the developer layer conveyed to the developing area is determined by the distance between the tip of the layer thickness regulating member (the end facing the developing roll) and the surface of the developing roll, that is, the layer thickness regulating gap. Is determined. It is desired that the layer thickness regulating gap be constant in the axial direction of the developing roll. The developing container is made of a material such as resin or aluminum. However, when the developing container expands, shrinks, or twists due to a change in environment, the layer thickness regulation gap changes. In order to prevent the layer thickness regulation gap from changing due to the occurrence of the elongation, shrinkage, twist, etc., it is conceivable to increase the rigidity of the entire developing container, but in that case, the cost is increased and the developing container is reduced in size. It becomes difficult to convert.

Instead of increasing the rigidity of the entire developing container, only the portion supporting the layer thickness regulating member of the developing container is increased in rigidity so that it is difficult to deform, and the other portion of the developing container is deformable. It is considered that the configuration can suppress the change in the thickness regulation gap without increasing the cost. In particular, as a method of setting the interval between the developing roll and the image carrier (photoconductor), a method of pressing the developing container against the image carrier with a spring or the like and pressing the tracking roll provided on the developing roll shaft against the photoconductor shaft is used. In the case of adoption, the other portion of the developing container (a portion other than the portion supporting the layer thickness regulating member) with a small force.
Needs to be deformed.

When a two-component developer having a carrier and a toner is used, if the layer thickness regulation gap is narrow, the developer tends to be clogged. Is attached inside the developing container. Since the number of components and the number of work steps using this configuration increase, there is a problem that the cost increases. Also, Japanese Patent Application Laid-Open No.
No. 745, when the layer thickness regulating member is composed of only a magnetic substance, the magnetic substance is pulled by the magnetic force of the magnet roll of the developing roll. There is a problem that it is not narrow. In order to improve this, a layer thickness regulating member made of a magnetic material having high rigidity is required, and there is a problem that the required space and cost increase.

In view of the above circumstances, the present invention relates to a developing device for use in an electrophotographic image forming apparatus, wherein
The contents described in 1) shall be the subject. (O01) To reduce a change in the layer thickness regulation gap while suppressing an increase in the manufacturing cost of the developing device.

[0007]

Means for Solving the Problems Next, the present invention for solving the above-mentioned problems will be described. Elements of the present invention are described in order to facilitate correspondence with the elements of the embodiments described later. The sign of parentheses is added in parentheses. The reason why the present invention is described in correspondence with the reference numerals of the following embodiments is to facilitate understanding of the present invention, and not to limit the scope of the present invention to the embodiments.

(The present invention) In order to solve the above-mentioned problems, a developing device of the present invention is characterized by having the following requirements (A01) to (A03). (A01) Image carrier (PRy, PR) on which an electrostatic latent image is formed
m, PRc, PRk) and the development areas (Q2y, Q2m,
Q2c, Q2k), a developing container (V) rotatably supporting a developer roll (Ga) for transporting the developer and containing the developer; (A02) developing the developer along the surface of the rotating developing roll (Ga); In the layer thickness adjustment region, which is the upstream portion of the regions (Q2y, Q2m, Q2c, Q2k), the layer is arranged to face the surface of the development roll (Ga) to adjust the layer thickness of the developer layer on the surface of the development roll (Ga). (A03) a high-rigidity container member which forms a part of the developing container (V) and is formed of a material having a higher rigidity than the material of other parts of the developing container (V) (V1) The high-rigidity container member (V1), wherein the layer thickness regulating member (3) is provided on an inner surface.

(Effect of the Present Invention) In the developing device of the present invention having the above-described configuration, the developing roller (Ga) rotatably supported by the developing container (V) for storing the developer has an electrostatic latent image. The developer is transported to the developing areas (Q2y, Q2m, Q2c, Q2k) facing the image carriers (PRy, PRm, PRc, PRk) to be formed. The layer thickness regulating member (3) is provided along the surface of the developing roll (Ga) rotating and moving along the developing areas (Q2y, Q2).
m, Q2c, Q2k), the layer is arranged to face the surface of the developing roll (Ga) in the layer thickness adjusting region, which is the upstream portion, and adjusts the layer thickness of the developer layer on the surface of the developing roll (Ga). The high-rigidity container member (V1) provided with the layer thickness regulating member (3) on the inner surface constitutes a part of the developing container (V) and is used as a material of another part of the developing container (V). It is formed of a material having higher rigidity. Since the high-rigidity container member (V1) has high rigidity, the deformation amount is small, and the internal stress generated by an external force acting on the developing container (V) and an environmental change such as temperature and humidity is reduced by the developing container. Since it is absorbed by the deformation of the other portion of (Ga) having relatively low rigidity, the deformation amount of the high-rigidity container member (V1) is reduced. Therefore, the amount of deformation of the high-rigidity container member (V1) is reduced, and the displacement of the layer thickness regulating member (3) is also reduced. For this reason, the layer thickness regulating member (3) and the developing roll (G
a) Since the change in the layer thickness regulation gap (D), which is the distance from the surface, is reduced, the layer thickness of the developer layer on the surface of the developing roll (Ga) can be made uniform.

[0010]

(Embodiment 1) Embodiment 1 of the present invention
The developing device according to the present invention has the following requirements (A04).
It is characterized by having. (A04) The layer thickness regulating member (3) integrally formed with the high rigid container member (V1) on the inner surface of the high rigid container member (V1).

(Operation of the First Embodiment) In the developing device of the first embodiment of the present invention having the above-described configuration, the high-rigid container member (V1) is integrated with the inner surface of the high-rigid container member (V1). Since the molded layer thickness regulating member (3) has high rigidity, the amount of deformation is small. Further, it is not necessary to separately manufacture the layer thickness regulating member or to attach it inside the developing container. For this reason, a developing device with a small change in the layer thickness regulation gap (D) can be manufactured at low cost.

(Embodiment 2) A developing apparatus according to Embodiment 2 of the present invention is characterized in that the following requirements (A05) and (A06) are provided in the present invention or Embodiment 1 of the present invention. I do. (A05) The developing roll (Ga) having a fixedly supported magnet roll (Ga1) having a plurality of magnetic poles on the outer peripheral surface and a developing sleeve (Ga2) rotating around the outer periphery of the magnet roll (Ga1); Is a magnetic plate (4) fixed in a laminated state on the upstream side in the developer transport direction of the layer thickness regulating member (3) arranged opposite to the surface of the developing roll (Ga), and the tip is the magnet. The magnetic plate (4) arranged substantially opposite to one of the magnetic poles of the roll (Ga1).

(Operation of the Second Embodiment) In the developing device of the second embodiment of the present invention having the above-described structure, the layer thickness regulating member (3) whose leading end is arranged to face the surface of the developing roll (Ga) is provided. The magnetic plate (4) fixed in a stacked state on the side surface on the upstream side in the developer transport direction of (2) has a leading end with a developing roll (Ga).
Of the magnet roll (Ga1). Therefore, a magnetic pole having a polarity opposite to the magnetic pole of the magnet roll (Ga1) is induced at the tip of the magnetic plate (4) (the end facing the developing roll (Ga)). For this reason, the magnetic material in the developer passing through the gap between the surface of the developing roll (Ga) and the magnetic plate (4) is attracted to the two magnetic poles to increase the volume of the developer and decrease the density. Since the gap can be set wide, clogging of foreign matters and the like does not occur. Therefore, the developer passing through the gap is less likely to be clogged.

(Embodiment 3) A developing device according to Embodiment 3 of the present invention is characterized in that the following requirement (A07) is satisfied in the above-mentioned invention or Embodiment 1 or 2 of the present invention. (A07) The layer thickness regulating member (3) The highly rigid container member having an inner surface with a constant distance from the surface of the developing roll (Ga) to guide the flow of the developer downstream and to keep the pressure of the developer constant. (V1).

(Operation of the Second Embodiment) In the developing device of the third embodiment of the present invention having the above configuration, the inner surface of the highly rigid container member (V1) on the downstream side of the layer thickness regulating member (3) is The distance from the surface of the developing roll (Ga) is constant, and guides the flow of the developer and keeps the pressure of the developer constant.

(Embodiment) Next, a specific example (embodiment) of an embodiment of an image forming apparatus provided with a developing device of the present invention will be described with reference to the drawings. It is not limited. To facilitate understanding of the following description, in the drawings, the front-rear direction is the X-axis direction, the right-left direction is the Y-axis direction, and the up-down direction is the Z-axis direction.
The directions indicated by -X, Y, -Y, Z, and -Z or the sides indicated are front, rear, right, left, upper, lower, or front, rear, right, left, upper, and lower, respectively. And Also, in the figure, those in which “•” is described in “○” mean an arrow pointing from the back of the paper to the front, and “×” in “○”.
Means that an arrow goes from the front to the back of the page.

(Embodiment) FIG. 1 is an overall explanatory view of an image forming apparatus having a developing device according to an embodiment of the present invention. The intermediate transfer belt and the image carrier unit are supported by the image forming apparatus main body so as to be vertically movable. It is a figure which shows the state which is arrange | positioned at a use position. FIG. 2 is a view showing a state in which the intermediate transfer belt and the image carrier unit have risen from the state shown in FIG. 1 and 2, the image forming apparatus U includes an automatic document feeder U1, an image scanner U2 having a platen glass PG supporting the same, and a printer U3. The automatic document feeder U1 includes a document feed tray TG1 on which a plurality of documents Gi to be copied are placed in an overlapping manner.
And the platen glass PG from the document feed tray TG1.
A document discharge tray TG2 from which the document Gi conveyed through the upper copy position (document reading position) is discharged. The image scanner U2 has a UI (user interface) through which a user inputs an operation command signal such as copy start, an exposure optical system A, an IPS (image processing system), and the like.

The reflected light from the document Gi conveyed on the platen glass PG by the image scanner U2 or a document (not shown) manually placed on the platen glass PG passes through the exposure optical system A. The signals are converted into R (red), G (green), and B (blue) electric signals by a CCD (solid-state imaging device). IPS (Image Processing System)
Represents the RGB electrical signal input from the CCD as Y
(Yellow), M (magenta), C (cyan), K
The image data is converted into (black) image data, temporarily stored, and output to the laser drive circuit DL of the printer U3 at predetermined timing as image data for forming a latent image.
IPS is K (black) when the original image is monochrome.
Only the image data is output to the laser drive circuit DL. The laser drive circuit DL has a separate laser drive circuit (not shown) for each color of Y, M, C, and K,
A laser drive signal corresponding to the image data input from the CPU at a predetermined timing, and a latent image writing laser diode (not shown) of each color of a latent image writing device ROS (hereinafter simply referred to as "ROS"). Output to The ROS (latent image writing device) includes the laser diode, the optical system, and a case CS1 that houses them.

In FIG. 1, developing devices Gy, Gm, Gc and Gk are supported on the upper surface of the ROS case CS1 (details will be described later), and images corresponding to the respective developing devices Gy, Gm, Gc and Gk are provided. Carriers PRy, PRm, PRc, PRk are arranged. The plurality of image carriers PRy, PRm, PRc, PRk are:
After being uniformly charged by the respective charging rolls CRy, CRm, CRc, CRk, the image writing areas Q1y, Q1m, Q1
At c and Q1k, the Y, M, C, and K laser beams Ly, emitted from the respective laser diodes (not shown) of the ROS,
An electrostatic latent image is formed on the surface by Lm, Lc, and Lk. The electrostatic latent images on the surfaces of the image carriers PRy, PRm, PRc, PRk are developed into toner images by developing devices (developing devices) Gy, Gm, Gc, Gk in the developing regions Q2y, Q2m, Q2c, Q2k.

The developed toner image is conveyed to primary transfer areas Q3y, Q3m, Q3c, and Q3k that contact the intermediate transfer belt B. The primary transfer areas Q3y, Q3m, Q3c, Q3k
, The primary transfer rolls T1y, T1m, T1c, and T1k disposed on the back side of the intermediate transfer belt B are provided with a controller C.
A primary transfer voltage having a polarity opposite to the charge polarity of the toner is applied at a predetermined timing from a power supply circuit (not shown) controlled by the control circuit. The toner images on the image carriers PRy to PRk are primarily transferred to the intermediate transfer belt B by the primary transfer rolls T1y, T1m, T1c, and T1k. The residual toner on the surface of the image carriers PRy, PRm, PRc, PRk after the primary transfer is removed by the image carrier cleaners CLy, CLm, CLc, CLk. Image carrier PR corresponding to each color of Y, M, C, K
y, PRm, PRc and PRk are each a charging roll CR
y, CRm, CRc, CRk and image carrier cleaner CL
The image carrier units Uy, Um, Uc, and Uk are configured by being connected to y, CLm, CLc, and CLk to form a unit.

A belt module (vertical moving member) BM is disposed above the image carriers PRy to PRk. The belt module BM includes the intermediate transfer belt B, a tension roll Rt, a walking roll Rw,
A belt supporting roll (Rt, Rw, Rf, T2a) including an idler roll (free roll) Rf and a backup roll T2a also serving as a driving roll;
y, T1m, T1c, T1k, a belt cleaner CLb, and a frame (not shown) for supporting them. The intermediate transfer belt B is connected to the belt support roll (R
t, Rw, Rf, T2a) so as to be rotatable.

FIG. 3 is an explanatory view of the elevating case supporting the belt module, showing a state in which the elevating case has been moved to the ascending position. FIG. 4 is a view showing a state in which the lifting case shown in FIG. 3 is lowered from the raised position shown in FIG.
3 and 4, an elevating case CS2 supporting the belt module BM is supported by a pair of left and right operating member housing cases F1 and F1 supported by a frame (not shown) of the printer U3 so as to be able to move up and down. . A handle support plate F1 is provided at the front end of the operating member housing case F1.
a is provided to protrude forward. A gear G1 is rotatably supported on a pair of left and right handle support plates F1a, F1a around fixed axes. Both ends of the handle HN are connected to the pair of left and right gears G1, G1. When the handle HN is rotated downward from the state of FIG.
, The gears G1 and G1 rotate.

A pair of front and rear rotatable gears G2, G3 are provided inside the operation member housing cases F1, F1.
And a rack RK that meshes with the gears G2 and G3 is supported so as to be able to move back and forth. The front end of the rack RK projects forward of the operating member housing case F1 and meshes with the gear G1. Pins PN, PN are fixed to the gears G2, G3, respectively, and the pins PN protrude outward from a circular opening formed in a side wall of the operating member housing case F1. When the handle HN is moved up and down, the gear G1 rotates and the rack RK moves back and forth. At this time, the gears G2 and G3 rotate and the pins PN,
PN moves up and down in an arc.

The elevating case CS2 includes an upper wall CS2a, a pair of lower walls CS2b and CS2b extending downward from the front and rear ends of the upper wall CS2a, and a pair of upper walls extending upward from the right and left ends of the upper wall CS2a. Side wall CS2c, CS2c
have. A pair of horizontal slots TK, TK are formed in the upper side walls CS2c and CS2c, respectively.
K and TK are holes through which pins PN that move up and down along the arc when the gears G2 and G3 rotate are PN. Pins PN, P passing through the horizontal slots TK, TK
The lifting case CS2 is supported by N. Therefore, when the handle HN is turned up and down, the pins PN move up and down, and the elevating case CS2 moves up and down with the up and down movement.

Module support rails MS for supporting the belt module BM are provided on the inner surfaces of the pair of lower side walls CS2b and CS2b. When the belt module BM is mounted on the elevating case CS2, it is inserted from the right side of the elevating case CS2 to the lower side of the upper wall CS2a. At this time, supported members (not shown) provided on the front side and the rear side of the belt module BM are supported and guided by the module supporting rails MS, MS. Belt module B inserted in lifting case CS2
M is fixed to the lifting case CS2 by fixing means (not shown). The lower surface of the elevating case CS2 is open, and the lower end portion of the belt module BM fixed to the elevating case CS2 protrudes below the lower surface of the elevating case CS2 (see FIGS. 1 and 2).

The lower wall CS before and after the elevating case CS1
Four rail support members RS are respectively supported by 1b and CS1b. A pair of front and rear rail support members R
S and RS support the front and rear ends of one guide rail RL extending in the front and rear direction. Guide rail RL
Are provided in total, and the photoreceptor cartridges Uy, Um, Uc, Uk are supported on each guide rail RL. Accordingly, the rail support member RS, the guide rail RL, and the image carrier units Uy, Um, Uc, Uk move up and down as the elevating case CS2 moves up and down.
At the raised position (see FIG. 2), the image carriers PRy, PRm, P
Rc and PRk move above the developing devices Gy, Gm, Gc and Gk. The image carriers PRy, PRm, PRc, PRk, which have moved above the developing devices Gy, Gm, Gc, Gk, can be slid back and forth (in the direction perpendicular to the screen, the X-axis direction) by the guide rails RL. .

A secondary transfer roll T2b is disposed so as to face the surface of the intermediate transfer belt B in contact with the backup roll T2a, and a secondary transfer area is provided in a region where the intermediate transfer belt B and the secondary transfer roll T2b face each other. Q4 is formed. The secondary transfer roll T2b is supported by the frame of the printer U3, and when the belt module BM moves up from the state shown in FIG. 1 to the position shown in FIG. 2 together with the elevating case CS2, the backup roll T2a moves relative to the secondary transfer roll T2b. It moves from the pressure contact position shown in FIG. 1 to the separated position shown in FIG. The backup roll T2a is grounded, and a secondary transfer voltage having a polarity opposite to the charge polarity of the toner is applied to the secondary transfer roll T2b at a predetermined timing from a power supply circuit (not shown) controlled by the controller C. A secondary transfer unit T2 is constituted by the rolls T2a and T2b.

The primary transfer areas Q3y, Q3m, Q3c, Q3k
The color toner images sequentially transferred and superimposed on the intermediate transfer belt B by the transfer units T1y, T1m, T1c, and T1k in the above-described manner are the same as those in the above-described 2.
The sheet is conveyed to the next transfer area Q4. Below the ROS, a plurality of paper feed trays TR1 to TR3 are slidably supported by a pair of left and right guide rails GR. The recording sheets S on the paper feed trays TR1 to TR3 are taken out by a pickup roll Rp, separated one by one by a separation roll Rs, and then sent to a registration roll Rr by a plurality of transport rolls Ra. The registration roller Rr is used to transfer the color toner image formed on the intermediate transfer belt B to the secondary transfer area Q4.
The recording sheet S is conveyed to the secondary transfer area Q4 at the same timing as the recording sheet S is conveyed. When the color toner image on the intermediate transfer belt B passes through the secondary transfer area Q4, the recording sheet S is transferred by the secondary transfer device T2.
Is transferred to The sheet conveying device SH is constituted by the elements indicated by the reference numerals Rp, Rs, Ra, Rr and the like. The intermediate transfer belt B after the secondary transfer is cleaned by a belt cleaner CLb.

The recording sheet S on which the toner image has been secondarily transferred is conveyed to a fixing area Q5 and passes through the fixing area Q5 formed in the pressure contact area between the heating roll Fh and the pressure roll Fp of the fixing device F. At this time, the sheet is heated and fixed, and is discharged from the discharge roller Rh to the discharge tray TRh. A release agent for improving the releasability of the recording sheet S from the heating roll is coated on the surface of the heating roll Fh with a release agent coating device F.
It is applied by a.

Above the belt module BM, Y
(Yellow), M (magenta), C (cyan), K
(Black) developer cassettes Ky, Km,
Kc and Kk are arranged. Each developer cassette Ky, K
m, Kc and Kk are stored in the developing devices Gy and G, respectively.
The developing devices Gy, Gm, Gc, and Gk are supplied from a developer supply path (not shown) in accordance with consumption of the developers m, Gc, and Gk.

(Detailed Description of Image Carrier Unit and Developing Device) FIG. 5 shows a developing device Gy supported on the upper surface of the case of the ROS shown in FIG. 1 and an image carrier movably arranged with respect to the developing device Gy. It is an enlarged view of unit Uy. FIG. 6 is an enlarged view of the main part of FIG. Next, the image carrier unit Uy and the developing device Gy will be described with reference to FIG. 5. The structures of the other developing devices Gm, Gc, Gk and the image carrier units Um, Uc, Uk are the same as those of Gy, Uy.

(Image Carrier Unit Uy) In FIG.
On the guide rail RL, a case CS3 of the image carrier cleaner CLy is slidably supported in a direction perpendicular to the screen (front-back direction, X-axis direction). The case CS4 integrally connected to the case CS3 is a member that supports the compression spring SP, the bearing J, and the charging roll CRy. The bearing J rotatably supports the shaft of the charging roll CRy, and is pressed toward the image carrier PRy by a compression coil spring SP. The charging roll CRy pressed against the image carrier PRy rotates along with the rotation of the image carrier PRy.

Bearing support members BS are fixed to both ends of the case CS3 in the front-rear direction (direction perpendicular to the screen), and each bearing support member BS supports a bearing BA. The image bearing members PRy are provided by bearings BA provided at both ends in the front-rear direction.
Are rotatably supported at both ends. The rear end of the image carrier PRy (the rear end of the screen) extends rearward of the bearing BA, and the rotational force is transmitted to a gear (not shown) mounted at the rear end. It is configured as follows. The image carrier PRy, the image carrier cleaner CLy, the charging roll CRy, the bearing support member BS, the bearing BA, and the like constitute an image carrier unit U2y, and the image carrier unit Uy moves up and down the elevating case CS. As a result, it moves up and down together with the rail support member RS and the guide rail RL.

(Developing Apparatus Gy) In FIG. 5, a pair of locking member insertion holes 1a, 1a and locking holes 1b which are separated in the left-right direction are formed in the upper surface plate 1 of the case CS1 of the ROS. The pair of locking member insertion holes 1a, 1a and the locking hole 1
b are provided at the front end and the rear end of the case CS1, respectively. In FIG. 5, the developing device Gy has plate-shaped fixing members 2 at both ends in the front-rear direction (the direction perpendicular to the screen, the X-axis direction). A pair of locking members 2a, 2a separated in the Y-axis direction) and a fitted projection 2b are provided. To fix the developing device Gy to the upper surface of the case CS1, the locking members 2a, 2
The developing device Gy is moved to the right (Y direction) while the a is inserted into the locking member insertion holes 1a. At this time, the locking members 2a, 2a enter the lower surface of the upper plate 1 of the case CS1, and the fitted projections 2b fit into the locking holes 1b. In this state, the developing device Gy is fixed on the upper surface of the case CS1.

The developing device Gy has a developing container V that stores the developer and rotatably supports the developing roll Ga and the developer stirring and conveying members Gb1 and Gb2. The developing roll Ga has a fixedly supported magnet roll Ga1 having a plurality of magnetic poles along a circumferential surface, and a developing sleeve Ga2 rotating around the outer periphery of the magnet roll Ga1. Development roll Ga
In order to develop the electrostatic latent image on the image carrier PRy into a toner image, the developer adhered to the surface of the developing roll Ga, that is, the surface of the developing sleeve Ga1, is transported to a development area Q2y facing the surface of the image carrier PRy. In order to transport the developer layer on the surface of the development roll Ga to the development area Q2y with an appropriate thickness,
The developing area Q2y along the surface of the rotating developing roll Ga
The layer thickness regulating member 3 is arranged on the upstream side (layer thickness adjustment region). The layer thickness regulating gap D, which is the distance between the tip of the layer thickness regulating member 3 and the surface of the developing roll Ga, is set to 0.7 mm, and the layer of the developer layer passing therethrough is set by the layer thickness regulating gap D. The thickness is adjusted. Preferably, the thickness regulation gap D is set to about 0.5 mm or more.

The portion forming the layer thickness adjusting region (the region on the upstream side of the developing region in the developing roll rotation direction) of the developing container V (the portion where the layer thickness adjusting region is formed) is formed of the material of the other portion of the developing container V. It is composed of a highly rigid container member V1 using a material having a relatively high rigidity. The high-rigidity container member V1 is made of a material that is high in rigidity and hard to deform as compared with the other parts of the developing container V. As shown in FIG. 5, the high-rigidity container member V1 extends in the axial direction of the developing roll at a position facing the lower surface of the developing roll Ga. High rigidity container member V
Both ends of the developing roll 1 in the axial direction are fixed to end walls at the axial ends of the developing container V. The high-rigidity container member V1 can be formed so as to include a part of the end wall at the axial end of the developing container V. As the high-rigidity material of the high-rigidity container member V1, a hard and non-stretchable material such as a reinforced resin containing glass fiber, a polycarbonate resin, an ABS resin, or the like can be used.

In this embodiment, the layer thickness regulating member 3 is formed integrally with the high rigid container member V1 so as to protrude from the inner surface of the high rigid container member V1. The layer thickness regulating member 3 is formed separately from the high-rigidity container member V1,
It is also possible to constitute so that it may be fixed to the inner surface of the first. The side surface of the layer thickness regulating member 3 on the upstream side in the developer transport direction forms a guide surface for the developer flow in the developing container V, and a magnetic plate 4 having a thickness of 0.5 mm and a height of 5 mm is formed on the guide surface. Has been fixed. The thickness of the magnetic plate 4 can be appropriately set within a range of about 1 mm or less and the height thereof can be set at about 10 mm or less. The magnetic plate 4 is disposed at a position substantially opposite to the magnetic pole of the magnet roll Ga1 of the developing roll Ga, and the leading end of the magnetic plate 4 (the end facing the developing roll Ga) has a polarity opposite to that of the magnetic pole of the magnet roll Ga1. A magnetic pole is induced.
Therefore, the carrier of the developer passing through the gap between the surface of the development roll Ga and the magnetic plate is attracted to the two magnetic poles, and the volume of the developer increases and the density decreases. Clogging due to foreign matter or the like does not occur.

The developer layer having passed through the layer thickness regulating gap D (see FIG. 6) becomes higher (thicker) downstream of the layer when passing through the layer thickness regulating member 3. On the downstream side of the layer thickness regulating member 3, the gap between the inner surface of the high-rigidity container member V1 and the surface of the developing roll is set such that the outer end of the developer layer passing through the layer thickness regulating gap D contacts. Therefore, the gap D is set to about twice or less of the thickness regulation gap D. Therefore,
In this embodiment, since the layer thickness regulating gap D is 0.7 mm, the gap between the inner surface of the highly rigid container member V1 and the developing roll surface is 1.4 m downstream of the layer thickness regulating member 3.
m or less. When the gap on the downstream side of the layer thickness regulating member 3 is set to be twice or less of the layer thickness regulating gap D, the outer end of the developer layer flowing (conveyed) through the gap on the downstream side of the layer thickness regulating member 3 is set. Part is high rigid container member V1
Flows while contacting the inner surface of the
It is possible to prevent the phenomenon that the developer adheres to and accumulates on the inner surface of the first surface.

(Operation of the Embodiment) In the developing device of the embodiment having the above-described configuration, the developing roll Ga rotatably supported by the developing container V for storing the developer contains an image on which an electrostatic latent image is formed. The developer is transported to the developing areas Q2y, Q2m, Q2c, Q2k facing the carriers PRy, PRm, PRc, PRk. The layer thickness regulating member 3 is disposed facing the surface of the developing roll Ga in a layer thickness adjusting region that is an upstream portion of the developing regions Q2y, Q2m, Q2c, and Q2k along the surface of the rotating developing roll Ga. The layer thickness of the developer layer on the surface of the roll Ga is adjusted. The high-rigidity container member V1 integrally formed on the inner surface with the layer thickness regulating member 3 constitutes a part of the developing container V and is made of a material having higher rigidity than the material of the other parts of the developing container V. It is formed. Since the high-rigidity container member V1 has high rigidity, the deformation amount is small, and the internal stress generated by an external force acting on the developing container V and an environmental change such as temperature and humidity is relatively small. Since the low rigidity is absorbed by the deformation of the other portion, the deformation amount of the high rigidity container member V1 is reduced.

Therefore, the amount of deformation of the high-rigidity container member V1 is small, and the displacement of the layer thickness regulating member 3 is also small. For this reason, the change in the layer thickness regulating gap D, which is the distance between the layer thickness regulating member 3 and the surface of the developing roll Ga, is reduced, so that the layer thickness of the developer layer on the surface of the developing roll Ga can be made uniform. Further, in this embodiment, since the layer thickness regulating member 3 is formed integrally with the high-rigidity container member V1, there is no need to separately manufacture the layer thickness regulating member or attach it to the inside of the developing container. Therefore, it is possible to manufacture a developing device having a small change in the thickness regulation gap D at low cost.

(Modifications) Although the embodiments of the present invention have been described in detail, the present invention is not limited to the above-described embodiments, but falls within the scope of the present invention described in the appended claims. Thus, various changes can be made. Modified embodiments of the present invention will be exemplified below. (H01) The present invention is applicable to developing devices having developing containers of various shapes other than the shapes shown in the embodiments.

[0042]

The above-described image forming apparatus of the present invention has the following effects. (E01) A change in the thickness regulation gap can be reduced while suppressing an increase in the manufacturing cost of the developing device. (E02) Further, when the layer thickness regulating member is integrally formed with the highly rigid container member, it is not necessary to manufacture the layer thickness regulating member separately or to attach it inside the developing container. Therefore, it is possible to manufacture a developing device having a small change in the thickness regulation gap D at low cost.

[Brief description of the drawings]

FIG. 1 is an overall explanatory view of an image forming apparatus having a developing device according to an embodiment of the present invention, in which an intermediate transfer belt and an image carrier unit supported up and down by an image forming apparatus main body are used; It is a figure showing the state where it is arranged in.

FIG. 2 is a view showing a state in which an intermediate transfer belt and an image carrier unit have risen from the state shown in FIG. 1;

FIG. 3 is an explanatory view of an elevating case supporting the belt module, showing a state in which the elevating case has moved to an ascending position.

FIG. 4 is a view showing a state in which the elevating case shown in FIG. 3 is lowered from a raised position shown in FIG.

FIG. 5 is an enlarged view of a developing device Gy supported on the upper surface of the case of the ROS shown in FIG. 1 and an image carrier unit Uy arranged so as to be able to move up and down with respect to the developing device Gy.

FIG. 6 is an enlarged view of a main part of FIG. 5;

[Explanation of symbols]

D: Layer thickness regulating gap, Ga: developing roll, Ga1: magnet roll, Ga2: developing sleeve, PRy, PRm, PRc,
PRk: image carrier, Q2y, Q2m, Q2c, Q2k: developing area, V: developing container, V1: high rigid container member, 3: layer thickness regulating member, 4: magnetic plate,

Claims (3)

[Claims] 1. A developing device having the following requirements (A01) to (A03): (A01) rotating a developing roll for transporting a developer to a developing area facing an image carrier on which an electrostatic latent image is formed; A developing container for supporting and storing the developer, (A02) being arranged to face the developing roll surface in a layer thickness adjusting region which is an upstream portion of the developing region along the rotating developing roller surface; (A03) a layer thickness regulating member for adjusting the layer thickness of the developer layer on the roll surface, which constitutes a part of the developing container and is formed of a material having a higher rigidity than a material of other parts of the developing container. The highly rigid container member, wherein the layer thickness regulating member is provided on an inner surface. 2. The developing device according to claim 1, which satisfies the following requirement (A04): (A04) the layer thickness regulating member integrally formed with the high-rigid container member on an inner surface of the high-rigid container member. 3. The developing device according to claim 1, which has the following requirements (A05) and (A06): (A05) a fixedly supported magnet roll having a plurality of magnetic poles on an outer peripheral surface thereof; (A06) a magnetic plate fixed in a stacked state to a side surface on the upstream side in the developer transport direction of the layer thickness regulating member, the tip of which is disposed so as to face the developing roll surface; The magnetic plate, wherein the tip is disposed to substantially face one of the magnetic poles of the magnet roll.