JP2002264383A - Imaging apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent image quality from deteriorating by stabilizing the interval between a developer carrier and the small hole of a means for controlling passage of developer. SOLUTION: The imaging apparatus comprises means 27 for regulating the position of a develop roller 11 relative to a member 4 for controlling passage of developer in the inserting direction of a developer supply unit and in the direction intersecting the inserting direction by touching the develop roller 11 at two or more different points in the circumferential direction thereof or on a plane extending along the circumferential direction when the developer supply unit integrating the develop roller 11 for transporting charged developer while carrying and a developer container is inserted into means for holding the developer supply unit.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus applied to a copying machine, a facsimile, a printer, and the like, and more particularly, to an image forming apparatus for ejecting a developer to a recording member to form an image.

[0002]

2. Description of the Related Art In recent years, in offices, with the improvement of personal computer capabilities and the advancement of network technology,
High-performance printers that can handle large volumes of documents,
Facsimiles and copiers are becoming widespread. On the other hand, color documents are also increasing due to the rapid spread of inkjet printers and the like. However, engines capable of outputting satisfactory black-and-white or color documents including printing speed are under development, and their appearance is expected.

One conventional image forming apparatus uses a direct marking method of forming an image directly on a recording member. For example, an image forming apparatus disclosed in JP-B-44-26333 proposes a developer injection type apparatus which is one of direct marking methods. This is achieved by inputting an image signal to an image signal electrode (control electrode) provided in a print head to generate an accelerating electric field, causing the charged developer to pass through a small hole near the image signal electrode, and passing the developer to a counter electrode. The recording material is landed by the voltage applied to the recording medium to form an image.

[0004] Using this type of image forming apparatus,
In order to form dots of the order, the distance between the control electrode or the small hole and the carrying means for carrying the developer is set to about several tens μm.
And a few hundred volts
It is necessary to selectively apply a high voltage of ~ 1000V. As described above, an image forming apparatus has been proposed which satisfies the problem of stabilizing the distance between the control electrode or the small hole and the carrying means for carrying the developer at 10 μm. Less than,
This image forming apparatus will be described with reference to FIG.

[0005] The image forming apparatus 700 is provided with a print head 701. Print head 701
The housing 702 has a right side open and a developer supply opening formed at the left end, and a small hole array 715 disposed on the left outer surface of the housing 702 so as to cover the developer supply opening. The formed developer passage control member 703 is provided. Further, the print head 701 is provided with a developing device 704 that is detachably installed in the housing 702. A back electrode 705 is provided on the left side of the print head 701 at an appropriate interval. Also, the back electrode 7
The recording member 706 is configured to pass between the print head 705 and the print head 701.

The developing device 704 is provided with a developer container 708 for storing a toner 707 as a developer. The developing device 704 includes a developer container 70.
A developing roller 709, which is a developer carrying unit, is provided so as to face a developer supply port which is largely opened on the left side of 8. Further, the toner 707 in the developer container 708 is agitated and frictionally charged in the developing device 704,
A supply roller 710 for supplying the toner 707 to the developing roller 709 is provided.

[0007] One end of the developer passage control member 703 is fixed to the housing member 702 by a fixing screw 711, the other end is bent by a stay 712, and the other end is a pair of tension springs 713. Is locked to the spring hook 714 via the.

Next, a mechanism for adjusting the distance between the developing roller 709 and the small hole 715 of the developer passage control member 703 will be described with reference to FIG. FIG. 8 is an enlarged view near the developing roller of the conventional image forming apparatus.

When the developing device 704 is inserted to a predetermined position of the housing 702, the developing roller 709 presses the developer passage control member 703 toward the back electrode 705. At this time, the outer peripheral surface of the developing roller 709 is
Contact at 0. Then, in a state where the developing roller 709 is interposed through the spacer 716, the developer passing control member 703 is pressed at the position 800 from the back side to the front side by the force F5. On the other hand, the other end of the developer passage control member 703 is suspended by a tension spring 713. For this reason, the tension spring 713
Is displaced by the pressing force of the developing roller 709 pressing the developer passage control member 703. As a result, the tension spring 71
With the restoring force of 3, the developer passage control member 703 presses the developing roller 709 with the force F6 with the spacer 716 interposed therebetween.

In this way, the developer passage control member 70
3 and the developing roller 709 press each other at the position 800 with the spacer 716 interposed therebetween, so that the distance between the back surface of the developer passage control member 703 and the outer peripheral surface of the developing roller 709 is Maintained in thickness.

By adjusting the thickness of the spacer 716, the distance between the toner layer on the developing roller 709 and the developer passage control member 703 can be adjusted. For example, by adopting a SUS plate material having a thickness of several tens of μm for the spacer 716, the small hole row 715 and the developing roller 709 can be formed.
Can be kept at about several hundred μ. Also, the spacer 71
When the predetermined position of the developing roller 709 comes into contact with the spacer 716 at the position 800, the distance x ₃ , x ₄ between the small hole 715 at the position where an image is currently formed and the developing roller 709 is appropriate. The distances are set so that the distances x ₃ and x ₄ are equal.

By using the spacer 716 in this manner, a predetermined voltage is applied to the small electrode 715 and the control electrode 801 disposed around the small hole 715 while keeping the distance between the small hole 715 and the developing roller 709 constant. This makes it possible to form an image of a desired density with dots of a desired size.

[0013]

However, the spacer 716 and the developing roller 709 contact only at the position 800. Therefore, the spacer 716 and the developing roller 7
In the contact portion at the position 800, the spacers 716 are pressed against each other only in the normal direction of the surface of the spacer 716. Therefore,
The developing roller 709 can be accurately aligned with respect to the normal direction of the position 800 of the spacer 716 (x direction in the drawing), but the normal direction of the spacer 716, that is, the developing device 704 (the developing roller 709) It easily shifts in a direction (y direction in the figure) that intersects with the insertion direction.

When the developing roller 709 is inserted with a deviation from the predetermined position in the y direction, the developer passing control member 703 which is a soft member is moved to the developing roller 7 which is a rigid member.
09 causes an inappropriate shape. For this reason,
Small hole 715 of developer passage control member 703 and developing roller 7
The distance to 09 becomes wider or narrower than a predetermined distance.

For example, as shown in FIG.
09 is above the predetermined position in the y direction, that is, the spacer 7
16, the developing roller 709 moves to a position 901 above a predetermined position 800 of the spacer 709.
At the predetermined position 800. The curvature of the peripheral surface of the developing roller 709 is larger than the curvature of the developer passage control member 703. Thus, the distance x _5, x ₆ with small holes 715 of the developing roller 709 developer passes control member 703 is wider for a given distance x _3, x _4. As a result, the amount of toner ejected from the small holes 715 decreases below a predetermined amount, and the density of the received image becomes lower than the predetermined density.

The vicinity of the leading end of the developing roller 709 in the insertion direction comes into contact with the spacer 716 and the developing roller 70
Since the curvature of the peripheral surface of 9 is larger than the curvature of the developer passing through the control member 703, rather than the distance x ₅ distance x ₆ increases.
Therefore, the amount of toner ejected from the small hole 715 differs in the y direction, and the density of the received image differs in the y direction.

Further, as shown in FIG.
09 is below the predetermined position in the y direction, that is, the spacer 71
In the case of shifting away from the center direction of 6 downward,
The predetermined position of the developing roller 709 does not come into contact with the predetermined position 800 of the spacer 709, and a position shifted from the predetermined position of the developing roller 709 toward the circumferential surface side comes into contact with the predetermined position 800. That is, the predetermined position of the developing roller 709 is located below the predetermined position in the y direction. Then, the portion of the developing roller 709 closest to the insertion direction moves from a predetermined position to a position closer to the small hole 715 of the developer passage control member 703. Thereby, the developing roller 709 and the small hole 71 of the developer passage control member 703 are formed.
The distances x ₇ and x _{8 to} 5 become narrower than the predetermined distances x ₃ and x ₄ . As a result, the amount of toner ejected from the small holes 715 increases more than a predetermined amount, and the density of the received image becomes higher than the predetermined density.

Further, when the distances x ₇ and x ₈ are further reduced, the toner accumulates near the small holes 715 of the developer passage control member 703 to form a hole or clog. In some cases, the amount of ejected toner is reduced, and the density of the received image is reduced.

The spacer 71 of the developing roller 709
6 is displaced from the predetermined position of the developing roller 709 toward the circumferential side of the developing roller 709 and the curvature of the peripheral surface of the developing roller 709 is larger than the curvature of the developer passage control member 703. x ₇ is greater than the distance x _8. Therefore, the amount of toner ejected from the small hole 715 differs in the y direction, and the density of the received image differs in the y direction.

The developing roller 709 is attached to and detached from the housing 702 every time the toner runs out. Therefore, a situation in which the contact position between the developing roller 709 and the spacer 716 changes easily occurs, and the positional relationship between the developing roller 709 and the small hole 715 easily changes.

The present invention has been made in view of the above circumstances, and an image forming apparatus for stabilizing a distance between a developer carrier and a small hole of a developer passage control unit, thereby preventing deterioration in image quality. The purpose is to provide.

[0022]

According to the present invention, there is provided an image forming apparatus, comprising: a developer supply device having a roller-shaped developer carrier for carrying and transporting a charged developer and a housing container for housing the developer; When the unit is inserted into the developer supply unit holding means, the developer carrier and the developer carrier come into contact with each other at two or more different points in the circumferential direction or at a surface along the circumferential direction, so that the developer in the developer carrier is A regulating means is provided for regulating the position of the developer supply unit with respect to the passage control member in the insertion direction and the position in the direction intersecting the insertion direction to predetermined positions.

Thus, the position of the developer carrier with respect to the developer passage control member can be restricted to a predetermined position in the insertion direction of the developer supply unit and in a direction intersecting the insertion direction. As a result, it is possible to prevent the image quality of the formed image from deteriorating.

[0024]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An image forming apparatus according to a first aspect of the present invention includes a roller-shaped developer carrier that carries and conveys a charged developer, and includes the developer carrier and the developer. A developer supply unit that integrates a storage container for storing the developer; a developer supply unit holding unit that detachably holds the developer supply unit in the apparatus main body; and a plurality of small holes through which the developer passes. A developer passage control member that is formed in a row in a direction perpendicular to the direction in which the developer is conveyed, and controls the passage of the developer through the small holes according to an external signal, A back electrode for generating an electric field for causing the developer to fly between the developer carrier and an image receiving medium on which the developer having passed through the small hole is attached, and a back electrode for the developer passage control member. Facing developer carrier And a surface along the circumferential direction at two or more different points in the circumferential direction of the developer carrier and the developer carrier when the developer supply unit is inserted into the developer supply unit holding means. By contacting at a predetermined position, the position of the developer supply unit with respect to the small hole of the developer carrier in the direction of insertion of the developer supply unit into the developer supply unit holding means and the position of the direction intersecting with the insertion direction are respectively set to predetermined positions. And a regulating means for regulating.

With this configuration, the restricting means can be brought into contact with the developer carrier and the developer carrier at two or more different points in the circumferential direction or at a surface along the circumferential direction. Thus, the regulating means can apply a pressing force in the insertion direction of the developer supply unit and a pressing force having a component intersecting the insertion direction to the developer carrier. As a result,
The distance between the back surface of the developer passage control member and the outer peripheral surface of the developer carrier is maintained at the thickness of the restricting means, and the distance in the direction intersecting the insertion direction of the developer passage control member and the developer carrier. The position is also maintained by the regulating means. In this way,
Since the positional relationship between the back surface of the developer passage control member and the outer peripheral surface of the developer carrier is regulated to be constant, accurate image formation can be performed.

According to a second aspect of the present invention, in the image forming apparatus according to the first aspect, the restricting means includes a portion substantially opposite to the curvature of the peripheral surface of the developer carrier at a portion facing the developer carrier. A configuration is adopted in which the spacer has a concave portion having the same curvature.

Since the spacer has such a concave portion, the spacer can be brought into contact with the developer carrier at two or more different points in the circumferential direction or at a surface along the circumferential direction.

According to a third aspect of the present invention, in the image forming apparatus according to the first aspect, the regulating means comprises a plate-shaped spacer provided at a position facing the developer carrier.
The spacer is provided between the spacer and the developer passage control member, and the spacer is in contact with two or more different points in the circumferential direction of the developer carrier and the developer carrier in a plane along the circumferential direction. And a spacer base to be bent.

According to this configuration, a conventional spacer can be used at two different points in the circumferential direction of a developer carrier and a developer carrier using a simple and inexpensive member called a spacer base without using a special spacer. Alternatively, it can be curved so as to be in contact with the surface along the circumferential direction. This can prevent an increase in the size of the device and an increase in cost.

Hereinafter, an image forming apparatus according to an embodiment of the present invention will be described with reference to FIG. FIG. 1 is a longitudinal sectional view showing a schematic configuration of an image forming apparatus according to an embodiment of the present invention.

As shown in FIG. 1, 4
A single housing member 2 having two housing portions 2 a to 2 d is provided detachably from the main body case 3. These housing portions 2a to 2d are provided with toners 8a to 8d as developers of four colors of yellow, magenta, cyan and black means.
Developer supply unit (hereinafter referred to as developing device)
It is configured to be detachable by horizontally inserting and removing 5a to 5d.

FIG. 2 is a partially enlarged view showing a detailed configuration of a recording portion of the image forming apparatus according to the above embodiment. A print head 1 is shown in the figure. The print head 1 has housing portions 2a to 2d having a right side open and a developer supply opening 10 formed at a left end portion, and housing portions 2a to 2d. A developer passage control member 4 disposed on the left outer surface of 2d so as to cover the developer supply opening 10;
and developing devices 5a to 5d which are removably installed in the housing d.

On the left side of the print head 1, a back electrode 6 is disposed at an appropriate interval, and the intermediate image receiving belt 7 is passed between the back electrode 6 and the print head 1. I have. The back electrode 6 is the main body case 3
The housing member 2 is removably positioned and fixed to the right side thereof.

The developing devices 5a to 5d are arranged so as to face a developer supply opening 10 on the left side of the developer container 9 for storing toners 8a to 8d as developers. A developing roller 11 which is a developer carrying means; a regulating blade 12 which regulates a toner layer carried by the developing roller 11 and conveyed outside the developer supply opening 10; and toners 8 a to 8 d in a developer accommodating container 9. And a supply roller 13 for supplying toner 8a to 8d to the developing roller 11 by agitating the toner and frictionally charging the toner.

Outside the both ends of the developing roller 11 in the axial direction,
A regulating collar 14 as first spacer means for abutting the back electrode 6 to regulate the distance between the developing roller 11 and the back electrode 6 at a constant level has an outer peripheral surface abutting the back electrode 6 and an inner peripheral surface thereof for developing. It is arranged in a state of contacting the outer diameter of the roller 11 or the outer diameter of a coaxial guide shaft 15 extending to both sides from the developing roller 11. Then, the distance between the back electrode 6 and the developing roller 11 in the regulating collar 14 is set to, for example, 150 to 1000 μm, and in this embodiment, to 350 μm. Also,
A guide shaft 15 coaxial with the developing roller 11 projects from both ends of the developer container 9. A drive gear (not shown) for transmitting a rotational driving force to the developing roller 11 is provided on at least one side of the guide shaft 15 via a one-way clutch (not shown) for rotating the developing roller 11 only in the CCW direction. It is arranged. With this configuration, the developing devices 5a to 5a
5d is inserted into the housing portions 2a to 2d, and the gear train (not shown) of the preceding stage is engaged, so that the developing roller 11
Is rotationally driven by a driving force of a driving means (not shown) separately.

The developing roller 11 is made of aluminum,
It is made of a metal such as iron or an alloy. In this embodiment, an aluminum cylinder having an outer diameter of 20 mm and a thickness of 1 mm is used. The regulating blade 12 is made of an elastic member such as urethane, has a hardness of 40 to 80 degrees (JISK6301A scale), has a free end length (length of a portion protruding from the mounting portion) of 5 to 15 mm, and extends to the developing roller 11. The linear pressure of 5 to 40 g / cm is appropriate, and one to three layers of toners 8 a to 8 d are formed on the developing roller 11. In the present embodiment, the regulating blade 12 is electrically floated.

The toners 8a to 8d are sandwiched between the developing roller 11 and the regulating blade 12, and receive a small charge from the developing roller 11 to receive and charge the toner. In the present embodiment, the toners 8a to 8d are made of a non-magnetic material having a negative charge of −10 μC / g and an average particle diameter of 8 μm.

The supply roller 13 is formed by providing a synthetic rubber such as urethane foam on a metal shaft such as iron (diameter: 8 mm in this embodiment) of about 2 to 6 mm, and has a hardness of 30 degrees (rolled shape). Is measured according to the method of the JIS K6301A scale), and assists charging of the toners 8a to 8d and controls supply. The amount of biting into the developing roller 11 is preferably about 0.1 to 2 mm.

The developing roller 11, the regulating blade 12, and the supply roller 13 may be electrically grounded, or a DC or AC voltage may be applied, or the regulating blade 12 may be electrically floated.

The back electrode 6 functions as a counter electrode and forms an electric field between the back electrode 6 and the developing roller 11, and is made of a metal plate or resin in which conductive fillers are dispersed. Although a DC voltage of about 500 to 2000 V is applied to the back electrode 6, a voltage of 1000 V is applied in the present embodiment.

Guide shafts 15 of the developing devices 5a to 5d are inserted into both end walls of the housing member 2 opposite to both ends of the developing roller 11 in the axial direction, thereby positioning the developing devices 5a to 5d, ie, the developing roller 11. A guide groove (not shown) is formed.

A fixing portion 19 for fixing one end of the developer passage control member 4 is formed on one side of the developer supply opening 10 of the housing member 2. On the other side of the developer supply opening 10, a stay portion 20 having an arc-shaped cross section that bends the other end of the developer passage control member 4 rightward is formed. Further, at the right end thereof, a spring hook 21 is provided at an appropriate interval. A head stopper 280 is provided upright at a predetermined position between the stay 20 and the spring hook 21.

The developer passage control member 4 is formed by a flexible printed circuit board (FPC). That is, as shown in FIG. 3, a plurality of small holes 23 are formed in the insulating base material 22 at a minute pitch along the width direction of the intermediate image receiving belt 7 to form one or a plurality of small hole rows 24. are doing. A ring-shaped image signal electrode (control electrode) 39 is formed on the surface of the insulating base material 22 so as to surround each small hole 23. Further, a diaphragm electrode 40 is formed on the back surface of the insulating base material 22.

The insulating base material 22 is made of a sheet-like flexible insulating material. The material of the insulating base 22 is preferably polyimide, polyethylene terephthalate, or the like, and the thickness of the insulating base is suitably from 10 to 100 μm. In the present embodiment, the insulating substrate 22 has a thickness of 5 mm.
0 μm polyimide is used. The diameter of the small hole 23 is 1
The image signal electrode 39 has a ring shape with an inner diameter of 150 μm and an outer diameter of 250 μm. The aperture electrode 40 has an inner diameter of 25 μm.
0 μm.

Further, the surface of each of the electrodes 39 and 40 is 1 to 1
An insulating layer 41 made of a thin resin layer of 0 μm is provided.
The image signal electrode 39 is made of a metal foil such as copper having a thickness of about 5 to 30 μm.

Each of the image signal electrodes 39 is also made of the insulating base material 2.
2 are independently connected to an image signal output unit serving as an image signal voltage switching unit via a lead wire 42 wired on the surface of the second device. Normally, a voltage of 400 V or less is applied to the image signal electrode 39, and in this embodiment, a voltage of 300V is applied for dot formation, and a voltage of -100V is applied for non-dot formation.

The developer passage control member 4 having the above structure is attached to the housing portions 2a to 2d. Specifically, one end of the developer passage control member 4 is fixed to the housing 2 by a fixing screw 25.
It is fixed to the fixing portions 19a to 2d. The other end of the developer passage control member 4 is connected to the developing device 5a by the stay 20.
It bends in the direction of 5d. In the vicinity of the other end 4a of the developer passage control member 4, a plurality of spring hook holes 4b are formed at intervals in the width direction of the developer passage control member 4. A tension spring 26 is bridged between each of the spring hook holes 4b and the spring hook 21. Thus, the developer passage control member 4 is suspended by the tension spring 26. The tension spring 26 is constituted by a coil spring. Due to this tension spring 26, the developer passage control member 4 is moved to the other end 4a.
In the direction of. Since the head stopper 280 is provided upright at the point where the developer passage control member 4 is pulled, the other end 4a of the developer passage control member 4 comes into contact with the head stopper 280, and the developer passage control member 4 Going beyond that is regulated.

With respect to the developer passage control member 4, the small holes 23
A vibrating mechanism is provided for removing the toner 8a to 8d when the toner 8a to 8d adheres to the inside or the periphery of the toner. That is, the metal diaphragm 43 is arranged along the small hole row 24 between the small hole row 24 and the fixing portion fixed by the fixing portion 19 and the fixing screw 25 on the back surface of the developer passage control member 4. It is stuck.
As the diaphragm 43, specifically, for example, a stainless plate having a plate width of 5 mm and a plate thickness of 0.2 mm can be used.

Ultrasonic vibration generating means 44 for generating ultrasonic vibration is fixedly supported on one of the outer wall portions of both end walls of the housing member 2, and the distal end extended to one end of the vibration plate 43 is It is screwed and fixed to the output end of the sound wave vibration generating means 44. As the vibration frequency of the ultrasonic vibration generation means 44,
It may be a sine wave of 1 MHz or less, for example, 20 KHz.
A degree is suitably used. This is because when the vibration frequency increases, the toner 8a to 8d and the developer passage control member 4
Are vibrated in the same manner, and it is impossible to prevent the adhesion and deposition of the toners 8a to 8d. The vibration plate 43 is configured to transmit ultrasonic vibration while permitting relative displacement between the ultrasonic vibration generation means 44 and the vibration plate 43.

Returning to FIG. 1, the overall configuration of the image forming apparatus will be described. A lid 36 is attached to the housing member 2 via a hinge 37 so as to be openable and closable. Pressing springs 38a to 3d corresponding to the developing units 5a to 5d
8d is attached. With this configuration, the housing 2
After the developing devices 5a to 5d have been inserted into the developing devices 5a to 5d, when the lid 36 is closed, the pressing springs 38a to 38d are turned into the developing devices 5a to 5d.
In the direction of the developer passage control member 4.

On the other hand, an endless intermediate image receiving means as an image receiving means is formed by sequentially passing between the developer passage control member 4 inserted in each of the housings 2a to 2d and the back electrode 6 and circulating and rotating. A belt 7 is provided. This intermediate image receiving belt 7
Is wound around a pair of belt rollers 29, 30.
A transfer roller 31 that transfers the toner image formed on the surface of the intermediate image receiving belt 7 to the recording paper 50 is provided so as to face one of the belt rollers 29. The recording paper 50 is stacked and housed in a paper feed tray 49 that can be inserted and removed at the left end of the main body case 3. A paper feed roller 51 that conveys the recording paper 50 is arranged near the paper discharge port of the paper feed tray 49. A paper feed guide 52 for guiding the recording paper 50 fed by the paper feed roller 51 to the nip between the belt roller 29 and the transfer roller 31 is provided. The recording paper 5 is provided on the discharge side of the belt roller 29 and the transfer roller 31.
0, a fixing device 54 for fixing the toner image transferred to the recording paper 50 to the recording paper 50 by thermocompression bonding, and a recording paper 5 after the fixing.
A paper discharge roller 55 that discharges 0 to a paper discharge tray 56 is sequentially arranged.

In the image forming apparatus according to the present embodiment, in order to form a high quality image, the small hole 23 of the developer passage control member 4 and the image signal electrode 39 near the small hole 23 are provided. A device for stabilizing the distance and the positional relationship with the outer peripheral surface of the developing roller 11 has been devised. Specifically, a spacer 27 that is curved to have substantially the same curvature as that of the outer peripheral surface of the developing roller 11 is provided as a second spacer means on the back surface of the insulating base material 22 of the developer passage control member 4. . Thereby, the spacer 27 is provided on the developing roller 11.
The contact is made in the direction of insertion of the developing roller 11, that is, the developing devices 5a to 5d, and the direction intersecting the direction of insertion. As a result, the developing roller 11 and the spacer 27
The developing rollers 11 are pressed against each other in the insertion direction and the direction intersecting the insertion direction. Therefore, the movement of the developing roller 11 in the insertion direction and the direction intersecting the insertion direction is restricted.

Hereinafter, the structure of the spacer 27 will be described with reference to FIG.
This will be described with reference to FIG. FIG. 4 is an enlarged view near the spacer of the image forming apparatus according to the above embodiment. As shown in FIG. 4, in the present image forming apparatus, a spacer 27 is fixed to the back surface of the insulating base material 22 of the developer passage control member 4 as a second spacer means. This spacer 27
Is located on the upper side of the small hole array 24 in the direction of transport of the developer by the developing roller 11 (the y direction side in the drawing). Further, between the end of the spacer 27 on the upper side in the developer conveying direction by the developing roller 11 and the developer passage control member 4, a spacer base 28 is provided so as to be in contact with the spacer 27 and the developer passage control member 4, respectively. Is provided.

The spacer base 28 is formed in such a size that it comes into contact with the upper end of the spacer 27 but does not come into contact with the lower end. Thus, only the upper end portion of the spacer 27 receives the force from the spacer base 28. As a result, the upper end portion of the spacer 27 curves toward the developing roller 11 side. The spacer base 28 has a thickness such that the curvature of the concave portion of the spacer 27 is curved so as to have substantially the same curvature as the curvature of the outer peripheral surface of the developing roller 11.

As described above, since the spacer 27 has the concave portion having substantially the same curvature as the curvature of the outer peripheral surface of the developing roller 11, the spacer 27 is positioned relative to the developing roller 11 at a position near the leading end in the insertion direction (FIG. 4). (Point C in the figure) and a point shifted from the point C in the circumferential direction of the developing roller 11, that is, a position (point D in the figure) in a direction intersecting the insertion direction. As a result, the spacer 27 can apply a pressing force F1 in the inserting direction of the developing roller 11 and a pressing force F2 having a component intersecting the inserting direction to the developing roller 11.

Further, the spacer base 28 is
7, when the developing roller 11 is bonded to the outer periphery of the developing roller 11, a position where the developing roller 11 can form an image accurately, that is, the distance x between the control electrode 39 around the small holes 23 and 24 and the outer periphery of the developing roller 11 _1, x ₂ is a predetermined distance, x ₁ and x ₂
Are arranged at positions where the spacers 27 are curved so that the distances are the same.

Next, the positioning of the developing roller 11 and the developer passage control member 4 by the spacer 27 and the spacer base 28 will be described.

When the developing devices 5a to 5d are inserted into the housing portions 2a to 2d of the housing member 2 to a predetermined position and the cover 36 is closed, pressing springs 38a to 38 attached to the inner surface of the cover 36 are provided.
d urges the developing devices 5a to 5d toward the back electrode 6 side. As a result, the developing roller 11 presses the developer passage control member 4 toward the back electrode 6. At this time, the developing roller 1
1 has a spacer 27 and a developing roller 1 from a point C.
1 from the line and point D along the longitudinal direction of developing roller 11
Contact at a line along the longitudinal direction of. That is, the developing roller 11 comes into contact with the spacer 27 at two points shifted from the peripheral surface of the developing roller 11.

Accordingly, in a state where the spacer 27 is interposed between the developing roller 11 and the developer passage control member 4, the pressing force F3 and the pressing force for pressing the developer passage control member 4 from the back side to the front side. F4 acts. On the other hand, since the other end 4 a of the developer passage control member 4 is suspended by the tension spring 26, the developing roller 11
The tension spring 26 is displaced by the pressing force F3 and the pressing force F4 that presses. Thus, the restoring force of the tension spring 26 causes the pressing force F <b> 1 and the pressing force F <b> 2 which are reaction forces to the pressing force F <b> 3 and the pressing force F <b> 4 to act on the developer passage control member 4 toward the developing roller 11. in this way,
The developer passage control member 4 is pressed toward the developing roller 11 in a direction along F1 and F2 with the spacer 27 interposed therebetween. As a result, the developer passage control member 4
And the developing roller 11 has a spacer 27 between them.
Are pressed against each other in the direction along the force F1 and the force F2 with the small holes 23 of the developer passage control member 4 interposed therebetween.
The distances x ₁ and x ₂ between the (back surface) and the outer peripheral surface of the developing roller 11 are maintained at the thickness of the spacer 27, and the developer passing control member 4 and the inserting direction of the developing roller 11 of the developing roller 11 (in the figure, The position in the direction (the y direction in the figure) intersecting with the (x direction) is also maintained by the spacer 27. The distance x ₁ , x ₂ between the image signal electrode 39 and the toner layer on the developing roller 11 and the position in the y direction orthogonal to the distances x ₁ , x ₂ are determined by the spacer 27 and the developer passage control member 4.
Is determined by the thickness of the insulating layer 41. Specifically, the distance between the toner layer on the developing roller 11 and the developer passage control means 4 by the spacer 27 is set with high accuracy in the range of 0 to 200 μm, and in the present embodiment, 50 μm.

As described above, according to the above embodiment,
The spacer 27 can be brought into contact with the developing roller 11 at two points C and D, which are shifted from the outer peripheral surface of the developing roller 11. As a result, the spacer 27 presses the developing roller 11 with the pressing force F1 having a component that intersects with the pressing force F1 in the direction of insertion of the developing roller
2 can act. As a result, the distance between the back surface of the developer passage control member 4 and the outer peripheral surface of the developing roller 11 is maintained at the thickness of the spacer 27, and the distance between the developer passage control member 4 and the developing roller 11 in the developing roller 11 insertion direction is maintained. The position in the crossing direction is also maintained by the spacer 27. In this manner, the positional relationship between the back surface of the developer passage control member 4 and the outer peripheral surface of the developing roller 11 is regulated to be constant, so that an image can be formed accurately.

According to the above-described embodiment, the conventional spacer 27 can be bent into an appropriate shape using a simple and inexpensive member such as the spacer base 28 without using any special spacer means. Can be. This can prevent an increase in the size of the device and an increase in cost.

In the above embodiment, the spacer 2
Although the embodiment has been described in the form in which the developing roller 11 and the developing roller 11 contact at points C and D, the spacer 27 and the developing roller 11 may be in contact with each other at two or more points shifted from the outer peripheral surface of the developing roller 11. good. The two or more points shifted to the outer peripheral surface of the developing roller 11 include lines extending in the longitudinal direction of the developing roller 11 from points C and D. Spacer 2
7 has a surface along the outer peripheral surface of the developing roller 11 (FIG. 4).
(A surface in the range indicated by E in the drawing).

In the above embodiment, the conventional spacer 27 is appropriately curved by using the spacer base 28. However, as shown in FIG. 5, the spacer base 28 and the spacer 27 are integrally formed. A configuration using the spacer 501 may be used. A concave portion 502 having substantially the same curvature as that of the outer peripheral surface of the developing roller 11 is formed in a portion of the spacer 501 facing the developing roller 11. Thereby, the spacer 501 is attached to the developing roller 11.
At two or more points C and D or between the points C and D. FIG. 5 is a diagram for explaining another example of the spacer according to the above embodiment.

In the above embodiment, the spacer 2
Although the description has been made using the plate-shaped spacer base 28 as a member that bends 7, the embodiment may use a spacer base 601 having an elliptical cross section as shown in FIG. The spacer table 601 also has a shape in which the spacer 27 is curved so as to be in contact with the outer peripheral surface of the developing roller 11 at two or more points C and D, or at a plane between the points C and D. FIG. 6 is a diagram for explaining another example of the spacer base according to the embodiment.

In the above embodiment, the spacer 2
7 is curved so that one spacer 27 is brought into contact with the outer peripheral surface of the developing roller 11 at two or more points C and D, or at a surface between the points C and D. May be used, and each spacer may be in contact with the outer peripheral surface of the developing roller 11 at two or more points C and D.

In the above embodiment, the spacer 2
7 and the spacer base 28 are provided only above the small holes 23 and 24, but the spacer 27 and the spacer base 2 are provided.
8 may be provided below, or above and below the small holes 23 and 24. However, since many members are provided in the vicinity of the developing roller 11 of the image forming apparatus and space is strict, it is preferable to provide only one spacer 27 and one spacer base 28. Further, since the space where the diaphragm 43 and the ultrasonic vibration generating means 44 are installed is very strict in the spacer 27 and the spacer base 28, the vibration plate 43 and the ultrasonic vibration generating means 44 are installed. It is preferably provided in a part different from a certain part.

[0067]

As described above, according to the present invention,
By the regulating means, the position of the developer carrier with respect to the developer passage control member can be regulated to a predetermined position in a position in the insertion direction of the developer supply unit and in a direction intersecting the insertion direction. It is possible to stabilize the interval between the small holes of the developer passage control means and prevent deterioration in the quality of the formed image.

[Brief description of the drawings]

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

FIG. 2 is a partially enlarged view showing a configuration of a recording portion of the image forming apparatus according to the embodiment.

3A is a partial plan view showing a front surface side of a developer passage control member according to the embodiment; FIG. 3B is a longitudinal sectional view showing a cross section of the developer passage control member according to the embodiment; Partial plan view showing the back side of the developer passage control member according to the embodiment.

FIG. 4 is an enlarged view of the vicinity of a spacer of the image forming apparatus according to the embodiment.

FIG. 5 is a view for explaining another example of the spacer according to the embodiment.

FIG. 6 is a view for explaining another example of the spacer base according to the embodiment.

FIG. 7 is a sectional view of a conventional image forming apparatus.

FIG. 8 is a first diagram illustrating a spacer of a conventional image forming apparatus.

FIG. 9 is a second diagram illustrating a spacer of the conventional image forming apparatus.

FIG. 10 is a third diagram illustrating a spacer of a conventional image forming apparatus.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 print head 2 housing member 3 main body case 4 developer passage control member 5 a to 5 d developing device 6 back electrode 7 intermediate image receiving belt 8 a to 8 d toner 9 developer storage container 10 developer supply opening 11 developing roller 12 regulating blade 13 supply Roller 14 Restriction collar 15 Guide shaft 19 Fixing portion 20 Stay portion 21 Spring hook 22 Insulating base material 23 Small hole 24 Small hole row 25 Fixing screw 26 Tension spring 27, 501 Spacer 28, 601 Spacer base 280 Head stopper 29 Belt roller 36 Cover Body 37 Hinge 38a-38d Press spring 39 Image signal electrode 40 Aperture electrode 41 Insulating layer 42 Lead wire

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2C162 AE12 AE25 AE31 AE47 AE56 AE69 AE74 AE84 AH14 CA03 CA12 CA24 2H029 DB04 DB13

Claims (3)

[Claims] A developer supply unit having a roller-shaped developer carrier that carries and transports the charged developer; a developer supply unit that integrates the developer carrier and a storage container that stores the developer; A developer supply unit holding means for detachably holding the developer supply unit in the apparatus main body; and a plurality of small holes through which the developer passes are formed in a row in a direction perpendicular to the developer conveyance direction. A developer passage control member that controls the passage of the developer through the small hole in accordance with a signal from the image forming apparatus, and an image receiving medium that attaches the developer that has passed through the small hole to the developer passage control member. A back electrode for generating an electric field for causing the developer to fly between the developer carrier and the developer supply control member provided at a position opposed to the developer carrier; Unit When the developer carrier is inserted into the image material supply unit holding means, the developer carrier and the developer carrier come into contact with each other at two or more different points in the circumferential direction or at a surface along the circumferential direction. Regulating means for regulating the position of the developer supply unit with respect to the small hole in the insertion direction of the developer supply unit holding means and the position in the direction intersecting with the insertion direction to predetermined positions, respectively. Image forming apparatus. 2. The image forming apparatus according to claim 1, wherein the restricting unit is a spacer having a concave portion having a curvature substantially equal to a curvature of a peripheral surface of the developer carrier at a portion facing the developer carrier. Item 2. The image forming apparatus according to Item 1. 3. The developer carrier according to claim 1, wherein the regulating unit is provided between the spacer and the developer passage control member, and a plate-shaped spacer provided at a position facing the developer carrier. And 2 in which the circumferential direction of the developer carrying member is different.
The image forming apparatus according to claim 1, further comprising: a spacer base that bends the spacer so as to be in contact with a point or more or a surface along the circumferential direction.